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SEMINARIO REGIONALSOBREAPLICACIONES AMBIENTALES

DE LOS ISOTOPOSY LAS RADIACIONE

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ORIGINAL ]

COHEN ARCAL XVICOMISION CHILENA DE ENEAOIA NUCLEAR

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XWS~CI~WSEMINARIO REGIONAL

SOBRE APLICACIONES DE LOS ISOTOPOS Y RADIACIONES PARA PAISES

DE AMERICA LATINA Y EL CARIBE

Resumenes de los Trabajos presentados al Seminario Regional sob re Aplicaciones de los Isdtopos y Radiaciones para palses de America Latina y el Caribe, realizado en Santiago de Chile,

entre el 9 y el 13 de Agosto de 1993. Organizado por el Organismo Intemacional de Energla Atdmica y la

Comisidn Chilena de Energla Nuclear.

ORGANISMO INTERNACIONAL DE ENERGIA ATOMICA COM1SION CHILENA DE ENERGIA NUCLEAR

1993

INTRODUCCION

El hombre estd cada dla mds conciente de los enormes transtomos que el acelerado crecimiento industrial produce en su medioambiente. Es por esto que, sin querer detener el avance tecnoldgico e industrial, estd haciendo frente al desafio de darse y heredar a las futuras generaciones una mejor tierra donde vivir.

Este nuevo concepto de vida lo ha llevado a desarrollar, promover y ejecutar acciones que le permiten mitigar o eliminar los efectos deietereos que su propio progreso ha ido generando, sin con esto renunciar a los beneficios del desarrollo.

Hoy, cuando la conciencia ambientalista de la humanidad gobierna muchas de nuestras decisiones, la tecnologia nuclear ya no se presenta como un problema, sino que por el contrario como una herramienta util para avanzar en el conocimiento y control de los desvastadores efectos de la polucion, demos- trando asf, una vez mis, que lo nuclear es una tecnologia necesaria para el desarrollo del hombre y su entorno.

A comienzos de 1980, se pone en marcha en Latino America un programa tendiente a combinar los esfuerzos a nivel regional en actividades especificas donde las aplicaciones nucleares presentaban altos niveles de uso y proyeccion. De esta manera se da inicio al programa Arreglos Regionales Cooperatives para America Latina (ARCAL), el que ha generado un nutrido intercambio regional. Dentro de este marco, a partir de 1992, se crea ARCAL XVI «Aplicaciones Industrials de la Tecnologia Nuclear® bajo cuyo auspicio se organize el Seminario Regional sobre Aplicaciones Ambientales de los Isdtopos y Radiacio- nes para Raises de America Latina y el Caribe.

Este evento fud organizado conjuntamente por el Organismo Internacio- nal de Energia Atdmica (OIEA) y la Comisidn Chilena de Energia Nuclear (CCHEN), y se llevo a cabo entre el 9 y el 13 de Agosto de 1993 en Santiago de Chile, siendo sede de dste evento el Centro de Estudio Nucleares «La Reina».

Asistieron en calidad de participates y expertos 55 investigadores, representantes de palses de Latinoamdrica y el Caribe. De esta manera estuvie- ron representados: Argentina, Brasil, Colombia, Costa Rica, Cuba, Chile, Ecua­dor, Guatemala, Mexico, Paraguay, Peru, Uruguay y Venezuela. En calidad de expertos invitados asistieron investigadores de Brasil, Canadd, Chile, USA, Francia, Gran Bretana, Japon y del OIEA. Ademds el seminario atrajo la a tendon de mas de 50 observadores provenientes de distintos sectores de la actividad nacional.

Los objetivos del seminario fueron los siguientes:• Conocer el nivel de desarrollo y aplicacidn de las radiaciones, las tecnicas

analiticas nucleares y los trazadores en los problemas del medio ambiente en los parses de la region.

• Discutir la problematica actual del medio ambiente en los parses de la Region.• Analizar el uso de tecnologras de irradiation e isotopicas, como agentes que

contribuyen a la elimination y control de elementos contaminantes del medio ambiente.

• Discutir y proponer soluciones concretas mediante el uso de irradiaciones e isdtopos que contribuyan al desarrollo del medioambiente en los parses de la region.

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INDICE

ASPECTOS GENERALES

Las politicos medio ambientales en ejecucidn v la elaboration en America Latina y el Caribe. Desafios de la presente Decada, N. Gligo......................................................... 7

Tecnologla Nuclear y Medio Ambiente, Y. Tabata..........................................................8

Programa del OlEA Sob re Aplicaciones de las radiaciones en, el Medio Ambiente, V, Markovic............................................................................................................................ 8

Aplicaciones de tecnicas analiticas nucleares en la investigation y monitoreo del medio ambiente v su relation con la salud: Una visidn general sob re un nuevo programa del OlEA R. Parr....................................................................................................................... 9

Metodologias y medios usados en estudios experimentales con trazadores en el transpor- te de contaminantes en agua C. Andre...........................................................................10

Estudios de aerosoles biogcnicos y biomasa combustionada y su rol en estudios de cambio atmosferico global P. Artaxo, V. Martins, F. Gerab, M. Yamasoe................. 11

PROCESOS DE IRRADIACION

Aplicaciones de Ios procesos de irradiation para control ambiental N. Frank..........12

Tratamiento de gases de combustion de carbon, mediante irradiation con aceleradores de electrones, D. Poli, J. Vieira, C. Campos, P. Rela.................................................... 13

Analisis tecnico del uso del tratamiento de gases dechimenea con electrones en Mexico G. Pina Villalpando, N. Frank....................................................................................... 14

Desinfeccion de aguas senidas por medio de irradiation utilizando aceleradores de electrones, S. Borrely, M. De Oliveira Sampa...............................................................15

Diseno y construction de una planta piloto para tratamiento de aguas servidas v efluentes industriales, mediante un acelerador de electrones, M. De Oliveira Sampa, J. Vieira, W. Calvo, P. Rela, S. Borrely.............................................................................. 16

Proyeccion del tratamiento de aguas y lodos residuales, M. de Zepeda, S. Molina, Y. de Juarez, J. Moreno, A. Colin.............................................................................................17

Dcscontaminacidn del rio Machdngara por radiaciones ionizantes, M. Sdnchez......17

Provecto de planta piloto para la irradiation de barros, J. Graino, N. Kaupert, G. Maggio,R. Gonzalez.......................................................................................................................18

Tratamiento de residuos celuldsicos mediante la irradiation con aceleradores de electro­nes y amonia, O. Kikuchi and N. del Mastro...............................................................19

Procesos de irradiation como una emergente tecnologla: Oportunidad para el tratamien­to de residuos, C. Chuaqui..............................................................................................20

Desarrollo de la tecnologla de curado en el revestimiento de maderas, utilizando aceleradores de electrones, M. Yamasaki, E. Araujo, M. Campos, R. Coelho, J. Geraldo............................................................................................................................. 21

Vulcanization por irradiation en la fabrication de Guantes quirurgicos de latex natu­ral, A. Souza, V. Canavel, S. de Araujo, S. Guedes, M. Contim.................................. 22

Utilization de UV y aceleradores de electrones en la tecnologla de curado en Brasil, situation actual y proyecciones, M. Yamasaki, W. Lima, E. Araujo............................ 23

Degradation y estabilidad de policarbonatos, esterilizados por ray os gama, E. Araujo,S. Guedes.......................................................................................................................... 24

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Apllcaciones ambientales del procesamlento de pollmeros por radiacidnA. B. Lugao......................................................................................................................26

Degradacidn radiolnducida de componentes de madera, C. Chuaqul...................... 27

SECCION TRAZADORES RADIACTICOS

Uso de trazadores radiactivos y medidores nuclednicos para la determinacitin de partfculas contaminantes transportadas en agua, P. Brisset....................................... 27

Nivel de desarrollo en Chile de tArnicas con trazadores aplicadas al medio ambiente, N. Hdresi...........'................................................................................................................. 28

Determinacidn de zonas de filtracidn en estanque natural de almacenamiento de agua y su posible efecto en el medio ambiente, O. Durin, F. Diaz......................................... 29

Determinacidn del tiempo de residencia y estudio de la distribucidn de la concentracion de un radiotrazador en una laguna de oxidacidn, J. Duque, O. Espinosa, G. Herrera29

Aplicacidn de radiotrazadores a los estudios sob re remocidn de metales pesados en afluentes lfquidos, J. Borroto......................................................................................... 30

TArnicas de radiotrazadores aplicadas a estudios del medio ambiente y control en la CETESB, S. Nakahira, M. Meciano, A. Martins............................................................ 31

Respuestas al trazado y modelacidn de corrientes urbanas, R. Moreira, V. Bomtempo, A.

Aplicacidn de tArnicas isotdpicasen la caracterizacidn preliminar de la contaminacibn del acuifero del gran Santiago, A. Silva, C. Salazar, A. Merino, A. Pollastri................... 32

Evaluacidn de los procesos de transformacidn de partfculas sblidas en plantas de produccidn de cemento mediante el uso de trazadores radioactivos C. Sebastian .... 33

Determinacidn de recambio de aguas subterrdneas en Abadia de Goias, estado de Goiana, por aplicacidn del mdtodo de tritio marcado artificialmente D. Poli, P. Aoki, V. Lepki, S. Saad, L. Araujo, G. Pedroso........................................................................... 34

Uso deHZn como trazador radioactive en estudios debioacumulacidn de zinc en poecil ia reticulada, W. Malagrino, B. Mazzilli........................................................................... 35

SECCION TECNICAS ANALITICAS NUCLEARES

Tdcnicas analiticas nucleares en el monitoreo e investigacidn en Chile: una visidn del estado actual y perspectives futuras, N. Gras............................................................... 35

El desarrollo de las tArnicas nucleares analiticas en el programs ARCAL IV y su contribucidn al estudio del problems del medio ambiente, M. Cohen, N. Gras, H. Vera- Ruiz.................................................................... 36

Desarrollo del 4rea ambiental y sanitaria en el Institute Tecnoldgico de Costa Rica , G. Castro............................................................................................................................... 36

Radionuclides y elementos traza de muestras ambientales en Brasil, C. Munita, I. Cunha, R. Paiva, R. Figuereida.................................................................................................... 37

TArnicas analiticas nucleares: herramientas para el estudio de la contaminacion del aire urbano, S. Landsberger................................................................................................... 39

Cuantificacidn de sulfatos en los aerosoles atmosfdricos de Santiago de Chile mediante la tArnica de dilucibn isotbpica, M. Prendez, J. Ortiz, S. Zolezzi................................ 39

Estudio de partfculas transportadas por el aire en Santiago, utilizando m Aodos quimicos y nucleares, P. Toro, H. Sandoval, R. Morales, M. Dinator, C. Romo.V. Cassorla, X. Rojas, 5. Marin, S. Olave, C, Aguila, N.Gras, S. Cornejo.......................................................... 40

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Intercomparacidn de concentradones elementales en aerosoles atmosfdricos determina- dos por PlXE Y AAN, V. Cassorla, X. Rojas, N. Gras, L. Chuaqul M. Dinator, J. Morales, F. Llona and C. Romo..................................................................................................... 41

Estudiosde polucidnen Paraguay: Concentracidn deelementos en la atmdsfera, usando tdcnicas anali'ticas nucleates relacionadas, V. Romero de Gonzdlez, Z. de Diaz,J. Cabello........................................................................................................................ ...

Vnriacidn anual de concentradones de Si, Ca, S, K en aerosoles atmosfdricos de Temuco, Chile, determinadas por PlXE, R. Figueroa, D. Caro, R. Morales, M. Dinator...........43

Composicion elemental de tres anillos de la cuenca del Amazonas, medidos por tdcnicas PlXE, J. Martins*, P. Artaxo, E. Ferraz......................................................................... 43

An.ilisis elemental de la fraccion soluble e insoluble en aerosoles atmosfdricos por PlXE Y XRF, M. Romo Kroger................................................................................................44

Andlisis de aerosoles atmosfericos ambientales por TRXRF., V. Poblete, P. Castillo, R. Figueroa, J. Gdlvez..........................................................................................................45

Aniilisis cuantitativo de sedimentos usando EDXRF, A. Carneiro, V. Nascimento... 46

Espectrometria de energia dispersiva para andlisis cristalogrdfico y qufmico de muestras minerales, E. Greaves, L. Sajo-Bobus, J. Sosa................................................................47

Uso de EDXRF en el diagnostico de problemas ambientales, R. Odino, B. Souto.....47

Uso de EDXRF con excitacidn radioisotdpica en el estudio de la dindmica de la vinaza en el suelo, S. Simabuco, V. Nascimento........................................................................... 48

Aplicaciones de PlXE al estudiode bioacumulacidn de metales en pescados de Rape!, M. Dinator, I. Villa, P. Auriol........................................................................................ . 49

Determinacidn del grado de contaminacidn por metales pesados a lo largo del litoral chileno, utilizando Perumytillus purouratus como biomonitor y tdcnicas nucleates y no nucleares como metodologias analiticas, L. Muftoz, N. Gras, S. Hurtado, H. Pinochet, 1. de Gregory, D. Delgado................................................................................................. ...

AnSlisis de elementos mayores y trazas en plasma sanguineo por PlXE. F. Llona, R. Morales...............................................................................................................................

Niveles de mercuric total en mujeres embarazadas y nodrizas residentes en pueblos de Pescadores en la octava region de Chile, C. Bruhn, A. Rodriguez, C. Barrios, VTlaramillo, U. Gonzalez, J. Becerra, NT Gras, O. Reyes....................................................................52

Concentracion de As en cabello mediante andlisis por activacidn neutrdnica, un monitor ambiental, A. Jar*tt, L. Pefta, M. Santander, N. Gras, L. Muftoz................................53

Coleccion de muestras bioldgicas y agua en zonas aisladas, para andlisis de trazas y ultratrazas mediante AAN, N. Gras, R. Downing....................................................... 54

Andlisis cuantitativo del contenido de radionucleidos gama emisores en algunos de los

Eroductos alimenticios de la dieta basica del venezolano L. Saio-Bobus, E. Greaves, . 'ehollain, H. Ferrer H., M. Guerra, J. Broadway, H. Ferrer R....................................55

Evaluacion de efectos subletales inducidos por la contaminacidn orgSnica, sob re la macro fauna bentonica de bahia Concepcion a travds de /adiosdtopos naturales, L. Farias, M. Salamanca....................................................................................................................... ...

Fuentes de 2mPb en la bahia de Concepcidn, M. Salamanca.........................................57

Aplicacidn de tecnologias nucleares en descontaminacidn de liquidos R. Labayru, E. Andalaft, C. Albornoz and M. Correa......................................................................... 57

El uso de isdtopos estables en geologia del medio ambiente y el control en polucidn minera, C. Roeschmann........................................................................................ ....... 58

Lista de expertos............................................................................................................ ...Lista de participates..................................................................................................... ...

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Invited Paper y1

LAS POLITICAS MEDIO AMBIENTALES EN EJECUCION Y ELABORACION EN AMERICA LATINA Y EL CARIBE. DESA- FIOS DE LA PRESENTE DECADA

N. GligoCEPAL/PNUMA, Santiago, Chile.

'f0\£L

[_ When adding the environmental issue to development and political strategies the amount of information the general public is overwhelmed with through the mass media amazes everyone. This discussion is held by governments, busines­smen, researchers, trade unions, producers, and consumers, among others. They all agree on the need of rejoining the human being with nature. On the other hand, International Agencies support the implementation of "Agenda 21», approved by the Conference on Environment and Development held in Rio de Janeiro in 1992.

In Latin America and the Caribbean, however, environmental problems are gradually becoming more critical as a result of deterioration due to pollution or over-exploitation of our natural resources." The so-called «lost decade» for economic growth and social well being also applies to the environment.

Doubtlessly, all our environmental problems are linked to the type of develop­ment we have selected. Economic indicators are showing positive signs for the region, but countries are showing clear sings of deterioration as far as life quality is concerned. That is the time when the equity and environmental sustainability issues become important.

Clearly, economic growth in most countries in the region has gone against the environment, a fact that challenges the sustainability of the development model that has been adopted. In order to reverse the said situation, the conception of development should be greatly changed, by including the environmental issue, not as an additional variable, but as a dimension both intrinsic and overlapping development, f

\ The economicism has imposed a sort of fever for assessing everything from a( merely economic stand point. Many of the environmental problems are not

sensed by the economic measurement instrument because they do not go through the market or because its full development is so long that any measu­rement will minimize its current value. The said economicism in the develop­ment strategies of our countries tend to excessively favor the management of macroeconomic variables, thus making them a development end rather than

' useful tools for attaining an adequate life quality.

'j* The environmental problems, the use of our natural resources, the protectionist barriers in foreign market should all lead us to addres a development concept where science and technology play a major role. Yet, we must warn that the global environmental imbalance theory should not make us change our own priorities.

There are certain trends stating the environmental issue should be solved through technology transfer, not taking into consideration that most environ­

7

mental problems result from structural problems, such us ownership of natural resources, short-term attitude, rationality not encompassing external factors, and so forth.

The solution paths should start from the thorough knowledge of the meaning of our natural heritage within the integrated knowledge of the ecosystem, interac­ting with science and society knowledge. Such is a topic several presentation during this seminary will make a significant contribution to.H

Invited Paper QL/ TECNOLOGIA NUCLEAR Y MEDIO AMBIENTE

Y.TabataJapan Atomic Energy Commission, Tokio, Japan.

L Nuclear technologies are widely and closely related to the environmental matters. Environmental problems are now very urgent to be solved. Also, there is a strong need to find possible solutions for the future. Environmental issues, often, are not only of local importance, but may have also the global importance in terms of keeping the living environment to be clean and the nature preserved. Present status and future prospects of nuclear technologies in conjunction with environmental issues are reviewed and discussed.

The main subject of presentation include:- energy saving,- alternative energy sources,- detoxification of polluted waste gases,- radiation treatment of water,- radiation processing, n

Invited Paper/ PROGRAM A DEL OIEA SOBRE APLICACIONES DE LAS

RADIACIONES EN EL MEDIO AMBIENTE

V. MarkovicInternational Atomic Energy Agency, Vienna, Austria.

C It is the mandate of the International Atomic Energy Agency (IAEA) to promote peaceful applications of nuclear energy, radiation and isotope applica­tions. The environmental concerns have the high priority in the Agency progra­mmes. This presentation will focus on one particular segment of the Agency programme: radiation processing, or use radiation for different industrial applications. The environmental benefits of radiation processing can be sum­marized in two main categories:

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1. Radiation processing, as a clean technology, which does not produce neither radioactive nor other waste, can replace other, more polluting technologies. Several examples will be given: radiation sterilization, radiation curing, etc.

2. Radiation processing can be applied also for active conservation of environment: purification of flue gases, decontamination of water and municipal waste, cleaning of industrial and hospital waste, etc.

Most, if not all of these aspects are included in the Agency programme on development and transfer of radiation technology.

Promotion of technology and environmental benefits are emphasized through activities such as, international meetings (interregional, regional), support to the organization of national meeting, etc.

Development is supported through organization and implementation of coordinated research programme and small scientific meetings.

Transfer of technology is carried out mainly through technical assistance programme. These programmes can be the country programmes (bilateral), or more and more common, regional cooperative programmes. Regional progra­mmes on industrial applications of isotopes and radiation are being implemen­ted in all main regions. ARCAL XVI is one of the examples.

The main aspects and character of these programmes will be illustrated with some typical examples. *~7

/Invited Paper cLPi'WOftAPLICACIONES DE TECNICAS ANALITICAS NUCLEARES EN LA INVESTIGACION Y MONITORED DEL MEDIO AM- BIENTE Y SU RELACION CON LA SALUD: UNA VISION GENERAL SOBRE UN NUEVO PROGRAMA DEL OIEA

R. Parr.International Atomic Energy Agency, Vienna, Austria.

L Nuclear and nuclear-related analytical techniques (mainly NAA, ED- XRF and PIXE) have an important role in programmes of the IAEA on health- related environmental monitoring and research. Most of this work is supported through the Research Contract and Technical Co-operation Programmes. An overview of some recent programmes will be given in this presentation with examples drawn from studies of airborne particulate matter, solid wastes and biological indicators of pollution, such as human hair. A new programme, due to start in 1995, will deal with occupational health exposure. Much of the IAEA's work in these fields is concerned with analytical quality assurance (AQA). In addition to preparing and distributing its own analytical quality controls materials, the IAEA also maintains a database of biological and environmental reference materials, for trace elements and some other analytes, that are availa-

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ble internationally from any supplier. This database is currently being updated in a collaborative project with UNEP. Many of the materials in the database have been certified with the aid of NAA and/or are suitable for the quality control of measurements made by nuclear analytical techniques. New materials in preparation under the IAEA's own programme of Analytical Quality Control Services include a lichen reference material (for trace elements) and human hair (for total and methyl-mercury). Future AQA projects are expected to focus on (i) providing assistance in the implementation of ISO-25 requirements for the competence of calibration and testing laboratories, and (ii) the development of protocols for sampling and sample preparation of environmental samples for analysis by nuclear analytical techniques. An overview of all these programmes will be given in this presentation and illustrated by representative data. ~~

■ OL^OOOJ£Invited Paper

/ METODOLOGIAS Y MEDIOS USADOS EN ESTUDIOS EX-

PERIMENTaLES CON TRAZADORES EN EL TRANSPORTE DE CONTAMINANTES EN AGUA.

C. AndreCentre d'etudes Nucleates de Grenoble, Grenoble, France.

Transport of pollutant in hydrological environment is a problem largelly encountered in various fields, since it is a consequence of human activity.

It's prediction becomes a necessity as well for prevention purpose as for remediation operations. Such an objective needs a good knowledge of the pollutant and of the geological medium which interact eachotners, and of the hydrodynamic parameters of the natural medium since water is generally by the career of the pollution. This constitutes the first step of the methodology, which can be called a "characterization step», the second one beeing the use of a mathematical model that couples the two components:

- the transport component, and- the pollutant-natural medium interaction component.

In this methodology, radioactive tracers are of great help because:- they are specific, which means that one can select the right tracer element having the same property as the bulk component under interest (the water, the pollutant, or a specific component to be investigated),- they are sensitive because of the in tr insec property of radioactive material which allows detection at very low levels,- as far as gamma emitters are concerned, detection can be made in situ in a non intrusive and non destructive way through experimental vessels.

This last point permits to elaborate specific experiments which give a lot of informations not accessible by conver" nal means.

The presentation will focus on the approach used in our laboratory to solve practical pollution problems, that includes three points:

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- laboratory experiments (batch, column and diffusion cells) with the pollutant and soil sample to be studied: in these experiments, the transport component is generally well characterized so the main objective is to identify the interaction mechanims, and to select a relay substance which will act as the pollutant if field experiments are necessary for validation,- experimental site experiments: they are realized both with a good tracer of water in order to characterize the transport component (water velocity and dispersity parameters), and a selected relay substance: this substance gives access to the in situ parameters of the pollutant- soil interaction, which are often different from the parameters measured through labora­tory experiments since the soil sample can be damaged during the extrac­tion procedure.

Morever, it is choosed so that it's transit time is smaller than that of the pollutant (weaker soil interaction), giving observation times more realistic than with the pollutant.

- geochemical modelling tools which are validated by laboratory (small scale) and field (larger scale) experiments, and allow prediction of the pollutant migration in a natural medium whose parameters are well known.

Some experimental and field results will be given as illustration of this methology.

PInvited Paper

ESTUDIOS DE AEROSOLES BIOGENICOS Y BIOMASA COMBUSTIONADA Y SU ROL EN ESTUDIOS DE CAMBIO ATMOSFERICO GLOBAL

P. Artaxo, V. Martins, F. Gerab,M. YamasoeInstitute de Flsica, Universidad de Sao Paulo, Brasil.

j Large emissions of aerosol particles and gases result from biomass burfilng in tropical regions. These particles have strong radiactive properties and can travel for long distances. The southern hemisphere is heavily loaded with particle from biomass burning, particularly in the Amazon Basin, Africa and Southeast Asia.

In order to study properties of naturally-released and biomass burning- released particles, three long term aerosol monitoring stations are being opera­ted in the Amazon Basin. Aerosol mass concentration, black carbon and trace elements are determined continuously using stacked filter units (SFUs). Particle induced X-ray emission (PIXE) is used to measure concentrations of up to 22 elements. Ions chromatography is used to measure nitrates, sulphates and several other ionic components. A new dedicated PIXE facility at the "Labora­tory de Analise de Materials por Feixes Ionicos - LAMFI» is being used.

The effects of biomass burning emissions are clearly observed for all three

11

background monitoring sampling stations. The elements associated with these emissions are: potassium, phosphorus, chlorine, zinc, black carbon and others.

Inside the Amazon Basin, long range transport occurs for distances of several thousands kilometers. SFU samples collected at Ascension Island, in the middle of Atlantic Ocean, show clearly the long range transport from Africa and Brazil.

In Malaysia, very high concentrations of biomass burning aerosol are observed during the dry season. *1

Invited Paper

APLICACIONES DE LOS PROCESOS DE IRRADIACION PARA CONTROL AMBIENTAL

N. FrankEbara Environmental Co., USA.

L. During recent years electron beam accelerators have been widely used for several established technologies such as radiation sterilization of medical su­pplies, radiation cross-linking and radiation curing. All of these radiation processing applications use Cobalt-60 or conventional transformer type accele­rators.

These are many emerging technologies in the environmental field that are getting wide spread interest such as electron beam processing of flue gases and the processing of industrial and municipal waste and waste water. Most of the emerging technologies have had several test, pilot and demostration facilities using conventional electron beam accelerator technology. The environmental applications for electron beam accelerator technology are as follows: 1. Flue gas clean-up, SO, and NO, removal; 2. Potable water; 3. Waste water treatment; 4. Sludge disinfection; 5. VOC removal and toxic control; 6. Soil remediation; 7. Medical waste treatment; 8. Food irradiation; 9. Others.

The seminar will cover a historical review of the development of electron beam process for environmental purposes. The longest term applications using accelerators is for flue gas clean-up to simultaneous remove the SO, and NO from the flue gas to turn it into a useful by-product, namely agricultural fertilizer. The discussions will illustrate the advancements made from the beginning of the testing to the present day to show that this process can be a viable alternative to flue gas desulfurization and selective catalytic reduction for SO, and NO, respectively. The power consumption of the total process has been lessened by several recent innovations for the distribution of electrons in the process vessel, which makes it very competitive with FGD/SCR systems.

Other applications for this technology for the treatment of gases will be discussed illustrating how the process can be used to remove volatile organic compounds from ventilation systems and how the process can be used to lessen toxic emissions from various gases such as the combustion gases from a municipal waste incinerator. Other applications in the gas field will include systems for treating medical waste, and the control of heavy metal emissions

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from flue gases.

The technology can also be utilized for potable water or waste water treatment to remove the objectional elements that could be found in water effluents from waste water treatment plants or in the water supplies for urban areas.

The technology can also be utilized for the treatment of solid waste such as sludges from waste water treatment plants, paper mills, and other processes that produce a sludge from processing. The disinfection effect of electron beam processing can offer more purified effluents.

There are other potential applications of this technology in various chemical processing applications where the effluent from the process has to be treated before the water is returned to the ground. The initial processing, and waste reduction, will then eliminate the necessity of having ground water contamination in many areas which causes wide spread clean-up using nume­rous technologies, including electron beam technology. This falls under the category of soil remediation where the soil has been contamined with PCB'S or PCE'S, or other toxics which then leach into the ground water. The technology can be used both as a preventative measure and a clean-up measure.

Pulsed-power is also being developed which could lower the cost of accelerators, and save construction costs because of their smaller size.

/

Other potential applications of electron beam processing technology are also emerging and illustrations of these applications will be shown both in respect to the prevention of pollution and also in respect to the clean-up of polluted areas. 1

■ J QL°i XCO1%ll TRATAMIENTO DE GASES DE COMBUSTION DE CAR­

BON, MEDIANTE IRRADIACION CON ACELERADORES DE ELECTRONES

D. Poll*, J. Vieira*, C. Campos*, P. Rela* V. Rivelli**, A. Albuquerque** *Instituto de Pesquisas Energdticas e Nucleares, IPEN-CNEN/SP, Brasil. **Companhia de Tecnologia de Sanea- mento Ambiental, Sao Paulo, SP. Brasil.

]L The air pollution caused by combustion flue gases from industrial plants has become a serious problem nowadays. The emissions and the reactions of S02 and NO, in the atmosphere are the most responsible for environmental pollu­tion and the cause of «acid rain*.

Specially in relation to the electrical power generating sector, the exhaus­tion of the competitive hydroelectric power potential in Brazil during the decade 2011/2020 will demand a program for the development of the national techno­logy capacitation in thermoelectrical power plants.

Until the end of this century, the participation of thermoelectric power in

13

the national power balance will be increased in the ratio compatible with the country's natural resources.

In such case, the development of efficient flue gas removal techniques (mainly SO, and NO,), will be necessary once Brazil has already started to set up limits for such pollutants (CONAMA resolution 06/12/91).

The remova of SO, and NO, by electron beam irradiation from simulated coal-fired flue gas will be studied using a small scale flow system which is being set up in order to obtain basic data for the process technical and economical feasibility concerning industrial applications.

The gas irradiation will be performed using an electron beam accelerator with 1.5MeV power, 25mA current from the Radiation Dynamics Inc., USA. The irradiation system was projected in order to investigate single, double and riple irradiation processes. 1

ANALISIS TECNICO DEL USO DEL TRATAMIENTO DE GASES DE CHIMENEA CON ELECTRONES EN MEXICO

G. Pifia Villalpando, *N. Frank Institute Nacional de Investigaciones Nucleares, Mexico, D.F., Mexico.* Ebara Environmental Corp., U.S.A

(..This work presents the results of a technical economical feasibility study of the potential use of the electron beam flue gas treatment in a Mexican thermoelectrical utility where heavy oil-high sulphur content is used as fuel.

Mexico is facing serious atmospheric pollution problems in some regions; such problems have been growing in the last years. As part of the main causes of this sitation: high poblational and vehicular concentration in some zones, use of fossil fuels with high sulphur content in industries, lack of control equipment for pollution emissions, electricity production based in the use of heavy oil, erosion of extended zones near urban centers, etc.

Because of the electricity production is one of the principal pollutants sources, some studies have started, related with the evaluation of different processes for SO, and NO, emission reduction, with features as: high removal efficiencies, obtention of useful byproducts and adaptability to existing utilities.

In this study, operational parameters of the electrical power plant «Tula» were used. Such plant is located 100 km far from Mexico City and situated inside a critical pollution zones, according to Mexican ecological authorities. Five 300- MWe units are located in that utility and heavy oil (3.7% sulphur) is used.

Two cases were considered in that study: a demonstration facility (capacity 20,000 Nm3/h) and a large installation for treatment of total flue gas flow from a 300 MWe unit (capacity 1.2 million Nm3/h); also, two SO,/NO, removal efficiency options were taken into account the minimum required to fulfill Mexican standards and the maximum achievable for this process. Both conceptual and preliminary designs were prepared for the considered cases.

14

Installation costs were also evaluated for both cases, taking into account present development of required equipments, mainly accelerators; those costs were compares with EPRI data, for only SO, removal conventional processes. It was observed they were similar. Such comparison shows the technical and economical advantages of this process for the Mexican case."!

DESINFECCION DE AGUAS SERVIDAS FOR MEDIO DE IRRADIACION UTILIZANDO ACELERADORES DE ELEC- TRONES

S. Borrely, M. De Oliveira Sampa Institute de Pesquisas Energdticas e Nucleates, IPEN-CNEN/SP, Brasil.

[As a result of fast urbanization, problems with pollution have grown to unexpected levels compromising air, water, soil and living organisns. Water has become increasingly scarce day after day partially due to the different contami­nants reaching it

Chlorination as a disinfectant method is not efficient enough for sewage and its use can generate organochloride compounds with values higher than the maximum permissible. Besides, chlorination is recommended for cleaned water only. These are some of the reasons to justify the application of new technolo­gies.

This paper considers the effect of ionizing radiation as a disinfectant method to te applied on sanitary field. An electron beam accelerator, Dynami- tron, 1,5 MeV, 25 mA was utilized in this study.

Considering that wastewater microorganism contamination includes an indigenous population of human enteric pathogens and some of them are radioresistant Bacillus species, the use of very low doses of radiation to inacti­vate all of them is not possible. It was then supposed a minimum and ideal irradiation dose to kill 90% of all microorganisms that could be present in any sewage (DIO). This value was 1,0 kGy.

The supposed ideal irradiation dose of 1,0 kGy was applied on samples from secondary effluent and on raw wastewater. In both situations this dose reduced total and fecal coliforms by 3 cycles log. After sample aeration, the irradiation efficiency was enhanced to 4 cycles log. The same dose was tested on Salmonella derby, Salmonella typhimurium, Salmonella meleagridis and Salmone­lla infantis added to phosphate buffer. In this case no colonies were formed, showing completely inactivation. "1

15

/^00y, ■■ / ’f«>

DISENO Y CONSTRUCCION DE UNA PLANTA PHOTO PARA TRATAMIENTO DE AGUAS SERVIDAS Y EFLUEN- TES INDUSTRIALES, MEDIANTS UN ACELERADOR DE

4 ELECTRON ES

M. De Oliveira Sampa, J. Vieira, W. Calvo, P. Rela, S. Borrely Institute de Pesquisas Energdticas e Nucleares, IPEN-CNEN,Sao Paulo, Brasil.

1_ In order to apply nuclear technology on environmental pollutants degra­dation and disinfection, IPEN developed a project including a pilot plant to treat wastewater and Industrial effluents In the Electron Beam Facility, 1,5 MeV Dynamitron type, beam current variable from 0 to 25 mA to obtain the desired dose. The electron beam is scanned to give an uniform coverage to a 120 cm length and 4cm width area.

Several experiments using high energy electron beam irradiation were performed in batch system. Samples were placed in Petri dishes and pyrex vessel to obtain different volumes. These results have encouraged the group to construct the plant.

The pilot plant was designed to receive 3 m3/h to 50Gy dose. Calorimetric system to control the dose was developed and the absorbed dose is measured in the stream immediately before and after the beam exposition.

After homogeneization, wastewater is taken from a storage tank (0.5 nV) by means of a pump leading through a flow meter, being the flow rate previously determined to submit the wastewater against the electron beam. To ob tain a homogeneous dose wastewater is then transported to an irradiation box especially buill; to this purpose.

Several parameters of the pilot plant and the Electron Beam Facility, such as current, voltage, flow, absorbed dose, are being monitored and recorded to determine the technical and economical evaluation of this methodology to be compared with conventional methods. ~l

16

PROYECCION DEL TRATAMIENTO DE AGUAS Y LODOS RESIDUALES . w?

M. de Zepeda*, S. Molina*,Y. de Juarez*, J. Moreno**, A. Colin***. * Nuclear Energy Directorate of Guate­mala** ININ Institute Nacional de Investiga- ciones Nucleares,***UAEM Universidad Autdnoma del Estado de Mexico, Mexico

l.The task undertaken in this paper is to motivate the participant at the

Seminar, to work inter institutionally in sludges and wastes water irradiation taken into consideration the advantages of this process. Guatemala Nuclear Energy Directorate and ININ, UAEM in Mexico started in this way and Guate­mala has been benefited from the ten years of the mexican experience and offer new investigations fields to them.

The sludges and wastes water irradiation is part of the OIEA-DGEN GUA 7185/RB (B-5 GUA 19438) contract recently started. The project was presented to relevant institutions in Guatemala who are worried because of the actual situation about the discharges to lakes and rivers (aproximatelly 30% of the city discharges are treated) offering support to this kind of projects and now they are involved on.

The Nuclear Directorate in Guatemala, had worked in a complete limno- logycal study of Amatitlan lake basin during last 5 years, including the carachte- rization of one of the city discharges, and its nocive effect to the basin as preliminary work.

The task is to evaluate reduction of bacterial load and recalcitrant subs­tances (polyaromatic hydrocarbons, detergents), total Nitrogen an Phospho­rous, orthophosphate and metals of sludge and waste waters. This results will permit to demonstrate the advantages of wastes water and sludges irradiation and to propose the agricultural use of them. ^

DESCONTAMINACION DEL RIO MACHANG ARA FOR RA- DIACIONES IONIZANTES

/ DP

M. SinchezEscuela PolitAcnica Nacional,Quito, Ecuador.

L The project is directed to present an alternative to solve the problem of microbiological contamination of the main river, Mach Angara, which crosses the city of Quito, capital of Ecuador. For this purpose two steps are planned: In the first one the quality of water of this river is studied, to use them as agriculture water for an surounding area close to Quito. The study includes: disolved

17

solids, biological of oxigen demand, disolved oxlgen, microbiological contami­nation, and the volume of water to be treated. In this first phase it is included the study of irradiation doses and the comparison of gamma irradiation and fast electrons irradiation to find cout the optimal conditions to reduce microbiologi­cal contamination of this river. The second phase of this project will cover the feasibility of the use the irradiation for the treatment of this river to use its water in agricultural purposes.

■ VJftOO&i1!PROYECTO DE PLANTA PILOTO PARA LA IRRADIACION DE BARROS

J. Graifio, N. Kaupert, G. Maggio, R.Gonzalez.Comisidn Nacional de Energfa Atdmica,Argentina

L In modem towns, the average inhabitant produces about 250 to 350 liters of sewage per day. Although these contain only a small quantity of solid wastes (sludges), it should be considered that, for example, the United States of America, some european countries and Canada are producing 10, 5 and 1 million tons a year, respectively. The figure for Argentina is estimated in the order of 1 million tons per year.

As the amounts of this type of waste shall be rapidly increasing, one of the problems that our civilization must face is how to dispose of such wastes in order to their distribution in the environment safely, avoiding the introduction of toxic and pathogenic substances.

Sewage treated with chlorine have some organic products that are toxic or carcinogenic. On the other hand, the sludge resulting from conventional treatments can be used as fertilizer. However, its utilization without a previous desinfection is not recommended and is considered, in fact, a source of pollu tion. Gamma radiation, as applied to sewage sludge, provides a method for the annihilation of pathogenes, the possibility of safely use of reusing the processed water. On these basis, the Atomic Energy National Commission (CNEA) designed a sewage slugde irradiation plant, using Co-60 radioactive sources that are being produced and exported by Argentina.

The irradiation plant will operate as an annex to a conventional treatment plant, which must provide aerobically digested sludges with a solid concentra­tion of 3% to 5%, The treatment will be accomplished in batches of 5.6 m3, with 30 min irradiation time, and a suitable recirculation and stirring system to ensure a uniform dose. Total activity of Co-60 will be 680.000 Ci. The required dose is 2 kGy with oxygenation and 3 kGy without oxygenation.

The Irradiation Plant will cover an area of 200 m1, will have a processing capability of 270 m3/day, and energy consuming less than 30 kw hour.

The designed plant can be adapted to the requirements of populations from 100.000 to 400.000 inhabitants without appreciable differences in the process efficiency.

18

The plant operation will be fully automatic and will be managed from a centralized control room by a minimum of personnel. It will have multiple safety and control systems to ensure a reliable and efficient operation.

The main characteristics of the desing are found in the irradiation recep­tacle, and next to which the transfering receptacle, both connected by the transfering duct for the new sources and all of them buried under ground -8m; also in the pumping systems for filling and emptying of the supplier and exit tanks, oxygenation system, refrigeration water circuit, and auxiliary systems such as the gantry crane.

The irradiation receptacle is a stainless steel cylinder 6 m'of capacity with a concrete bung 1.7 m of thickness, within which a ring-shaped cavity is holding the source.

The radioactive source is composed by pencils 33 cm long and 0.9 cm in diameter with and individual activity in the order of 7.000 Ci of Co-60, encap­sulated in groups of three in tubular elements which, in turn, are inserted into a ring-shaped source holder 50 cm in diameter that allows to store up to 113 elements, which is the estimated total need for 20 years operation. The initial load is 33 elements, aproximately equivalent to 700.000 Ci and the na tural decay makes it necessary to replace annualy 12.5% of the total activity, which is the achieved by adding new elements without removing the depleted ones.

The building will include also biochemical laboratory, repair workshop, administrative offices; and other installations.

Investment cost will be of aproximately US$ 2.000.000 without counting land value. The operation cost results to be US$ 4.8 per ton of treated sluge: it means 1 cent per inhabitant per month in a population of abou 1400.000 persons.

It has been carried out the basis engineering and made a mock-up representing the prototype plant. Nowadays it is going on with the product engineering, and the emplacement studies. 'I

TRATAMIENTO DE RESIDUOS CELULOSICOS MEDIAN­TS LA IRRADIACION CON ACELERADORES DE ELEC- TRONES Y AMONIA

O. Kikuchi and N. del Mastro Industrial Sc Engineering Application Coordination IPEN-CNEN,Sao Paulo, Brasil

In Brazil a huge amount of agricultural resources such as lignocellulosics coming from crop residues are discarded or under utilized. Upgrading of these wastes into useful end-products can be expected not only to recycle the agro- resources but also to reduce pollution. Cellulosic wastes are the most abundant renewable resource of organic carbon. The improvement of its quality is essential for cellulosic wastes to be used for animal feeds since the nutritive values of then are poor. Ionizing radiation can be used to degradate cellulose in

19

order to Increase the digestibility and ammonia could be used to increase N, content of those materials.

For a microscopical analysis, a combination of electron beam (EB) irradiation followed by gaseous anhydrous ammonnia treatment on cellulosic wastes such as sugarcane bagasse, cotton straw and rice hull was applied. Irradiation was carried out with an EB accelerator Dynamitron (Radiation Dynamic Inc), Energy 1.4 Mev, current 13.4 mA, doses 20 and 40 kGy. Cells were separated using a Franklin maceration solution modified by Norm and, dyed with safranin and observed under a Zeiss transmission and polarising micros­cope.

The tracheary elements, tracheids and vessel members, have their walls constituted mainly by polysaccharides, rich in cellulose microfibrils and with lignin deposited between the adjacent chains of polysaccharide. The fibres, one of the supportive tissue elements of the plant, have the second wall relatively tick, rich in cellulose, hemicellulose and lignin. The degradation of the cellulose and the hemicellulose by radiation occurs by a process of depolymerization. However, aromatic compounds in the lignin and other extractives seems to act as protective components against the radiation-induced scissions in the cellulo­se. The treatment and the doses used in this work was not enough to cause a drastic morphological changes within the fibres and the tracheary elements of sugarcane bagasse and other agricultural wastes, "j

Invited Paper

PROCESOS DE IRRADIACION COMO UNA EMERGENTE TECNOLOGIA: OPORTUNIDAD PARA EL TRATAMIENTO DE RESIDUOS

C. ChuaquiAECL Research, Winnipeg, Canada.

I_ In the presentation a brief description is given of the role of ionizing radiation in the treatment of different wastes. Wastes are classified according to physical state, origin and nature and the present status of radiation processing of wastes is given. The presentation continues by giving some detail informa­tion on the radiation treatment of sewage sludge, airline wastes, biomedical wastes, industrial and chemical wastes, flue gases and waste water. A brief discussion is presented on integrated processes, where wastes may yield several secondary products of commercial value. Finally, conclusions are presented. ]

20

w ‘uj'nuuu^ti-■DESARROLLO DE LA TECNOLOGIA DE CURADO EN EL REVESTIMIENTO DE MADERAS, UTILIZANDO ACELERA- DORES DE ELECTRONES

M. Yamasaki*, E Araujo*,M. Campos**, R. Coelho**,J. Geraldo*** Instituto de Pesquisas Energ£ticas e Nucleares, IPEN-CNEN, Sao Paulo, Brasil**Sayerlack Ind. Bras, de Vemizes S/A, Sao Paulo, Brasil.

LThe expanding worldwide concern about environmental protection and ects of releasing volatile organic compounds (VOC's) into the atmosphere is creating an increasing awareness of the utility and benefits of radiation curing

of inks, varnishes and coatings. Ultra-Violet and Electron Beam curing are known as a clear technology once they employ 100% solid chemicals and are for this reason used to replace polluting technologies.

The furniture industry, one of the largest consumers of low-solids, solvent-based coatings, needs consequently to reduce solvent emissons; in this case, radiation curing is one of the indicated technologies.

Low-energy electron beam and UV light combination is used to cure filters and clear varnishes or highly pigmented coatings applied to particle­board, hardboard or medium-density fiberboard (MDF). Coated products are used for furniture, doors and cabinets.

The Nuclear Energy Research Institute, IPEN-CNEN/SP and Sayerlack Brazilian Industry of Varnishes, have been working together since 1990, to develop the electron bean curing technology for wood derivate finishing. Highly pigmented such as white, black, brown and gray acrylated based coatings have been developed and studied.

This paper describes the irradiation conditions of the process and the dose distribution in function of the coating thickness. The influence of dose and dose rate on the end properties of the cured samples is presented. The experimental painting line with a curtain coaler, a reverse roll and a UV and a EB equipments installed at IPEN used to apply and cure fillers and topcoatings are also shown. The perfomance of the high gloss coated cured samples obtained for this process under physical, mechanical and chemical tests, is discussed, -i

CtftoW 77

VULCANIZACION POR IRRADIACION EN LA FABRICA- CION DE GUANTES QUIRURGICOS DE LATEX NATURAL

A. Souza*, V. Canavel*, S. de Araujo*, S. Guedes*, M. Contim**

, *Inst. de Pesquisas Energdticas e Nu-cleares-IPEN-CNEN/SP, Sao Paulo, Bra­sil.**F5brica de Artefatos de Ldtex Sao Ro­que, Sao Paulo, Brasil.

L The objective of thj<- work is to establish the best conditions for surgical

gloves fabrication by radiation vulcanization process of natural rubber latex.

Vulcanization process of natural rubber latex in the presence of sulfur is the most used in world, however there is an alternative vulcanization process with toxicological, economic and no pollutant advantages and producing rubber goods with best qualities. This alternative process is the radiation vulcanization of natural rubber latex. The method consists in the 1,4-cis- poliisoprene cross linking, dispersed in aqueous fase. It happens by radiation interaction of gamma rays from Co* or electrons beam from accelerators with polymeric molecules.

Gamma Rays

The vulcanization dose of 60% DRC national natural rubber latex was 200 kGy when it was vulcanized by gamma rays. Addition of compounds with high G value (sensitizer) to the latex increased the cross linking degree and decreased the vulcanization dose. Consequently this process becames more economical than traditional process when the vulcanization dose is small than 10 kGy. Ihe vulcanization dose of 200 kGy for natural rubber latex decreased to 40 kGy, to 10 kGy and to 9 kGy in the presence of CC14 / potassium laurate, n-butyl acrylate (n-BA) and n-BA / t-butyl hydroperoxide (t-BHP), respectively. Both n-BA and t-BHP tend to destabilize the natural rubber latex. The most effective stabilizer is KOH.

The results showed the sensitizing efficiency of three different systems. The CC14 / potassium laurate decreased 5 times the vulcanization dose and maximun tensile strength was small than without sensitizer. The n-BA / KOH decreased 20 times the vulcanization dose but in the presence of only 0.1 phr t- BHP decreased bellow 10 kGy and maximum tensile strength increased a little when compared with latex without sensitizer. The best sensitizer system was 3 phr n-BA-/ 0.1 phr t-BHP / 0.2 phr KOH.

Electrons Beam

The vulcanization dose of 60% DRC national natural rubber latex was the same 200 kGy. Therefore the dose rate did not affect the radiation vulcanization process without sensitizer. In the presence of the same sensitizer systems. The vulcanization dose decreased to 50 kGy for CC14 and n-BA and to 32 kGy for n- BA/t-BHP.

22

The effect of dose rate is on sensitizer. When the dose rate increased the vulcanization dose also increased and the maximum tensile decreased a little. The best sensitizer system for radiation vulcanization process with electrons beam was 5 phr n-BA / 0.1 phr t-BHP / 0.2 phr KOH.

Surgical Gloves Fabrication

National natural rubber latex was vulcanized by gamma rays and elec­trons beam and using each sensitizer system. Also it was vulcanized by the traditional process using sulfur. Surgical gloves were made in an factory by coagulant dipping process.

The comparative study of surgical gloves quality was carried out by physical and mechanical properties. The gamma rays vulcanization process is better than electrons beam vulcanization process.

When the surgical gloves was made by latex vulcanized by gamma rays the physical properties were the same and the mechanical properties obtained before and after aging at 70°C for 7 days were a little different for each sensitizer systems but they meet ASTM specification for surgical gloves. All properties were comparable to those of sulfur vulcanization gloves.

At point of view of mechanical properties the CC14 sensitizer was the best. But the economic point of view the n-BA / t-BPH was the best because can be vulcanized by gamma rays at small dose of 9 kGy. We chosen the last sensitizer system because the vulcanization dose was bellow 10 kGy and the mechanical properties were acceptable for surgical gloves commercialization.

Conclusions

1) The process of natural rubber latex vulcanization can be induced by gamma rays and electrons beam in the presence or absence of sensitizer.

2) The dose rate effects is on sensitizer.

3) The best conditions for surgical gloves fabrication by radiation vulcanization of natural rubber latex (60% DRC) were these: a) sensitizer 3 phr of n-BA / 0.1 phr of t-BHP / 0.2 phr of KOH; b) vulcanization dose = 9 kGy; c) gamma rays vulcanization, n

/ UTILIZACION DE UV Y ACELERADORES DE ELECTRONES EN LA TECNOLOGIA DE CURADO EN BRASIL. SITUACION ACTUAL Y PROYECCIONES

M. Yamasaki, W. Lima, E. Araujo Institute de Pesquisas Energeticas e Nucleares -IPEN-CNEN/SP, Brasil.

j Radiation curing using ultra violet and low energy electron beam of inks, varnishes, coatings and adhesives presents several important advantages from industrial point when compared to conventional systems based on polymers

23

' dispersed in volatile organic compounds (VOC's). Radiation curable materials are constituted by 100% solids, what means that UV/EB curable systems usually do not contain any solvents. The advantages within positive environmental impact, performance, productivity, quality improvement of cured products, energy saving, etc..., have resulted in the growth of this technology application with annual rates of 15% to 20%, since the early 1970s, in the most important North American, European and Asian countries.

In Brazil, the use of radiation curing began in 1960s, in wood finishing industries and this technology application is growing very slowly.

For this reason the Nuclear Energy Research Institute, IPEN-CNEN/SP, has been working since 1992, together with national formulators, equipments and chemicals suppliers, to detect the practical problems presented by the end users of UV/EB technology, other than spreading the radiation curing to the potential users.

The actual situation of radiation curing in Brazil and the prospects on several different industrial areas such as graphic arts, wood finishing, packa­ging, metal coatings and adhesives are presented. The number of UV and EB equipments installed and the consumption of radiation curable materials are shown. Besides, the results obtained with the training courses, technical seminars, workshops, debates and technical papers organized by IPEN and addressed to industrial representatives are discussed, "i

■GLCjloeO $£>DEGRADACION Y ESTABILIDAD DE POLICARBONATOS, ESTERILIZADOS FOR RAYOS GAMA

E. Araujo, S. GuedesInstitute de Pesquisas Energeticas eNucleares - IPEN-CNEN, Sao Paulo,Brasil.

H The purpose of this paper is to stabilize the national polycarbonate,

DUROLON, when it is sterilized by gamma rays and undesirable discoloration appears.

Aromatic polycarbonates are amorphous polymers usually prepared from bisphenols and phosgene by interfacial polymerization. It are employed in medical applications, including blood filters, dialyzers, oxygenators and sterilizing equipment. At present, the best process for sterilization of medical supplies is gamma irradiation. The two major effects of y-radiation in polymers are crosslinking and main chain scission. Both effects coexist and either one may predominate depending on the chemical structure of the polymer and the conditions of irradiation.

The national commercial polycarbonate studied was poly (bisphenol-A carbonate), DUROLON, used in medical applications, prepared by Policarbona- tosdp Brasil S/A. When this polymer is irradiated by gamma rays in air af room temperature occur scissions in main chain without crosslinking and its behavior is different from another polycarbonates, LEXAN and MACROLON. These scissions produce undesirable yellowness on DUROLON.

24

Degradation of Durolon

The radiolytic mechanism was investigated by FTIR, EPR, RMN and transmittance. FTIR spectra of irradiated samples (0-650 kGy). showed that the carbonyl index decreased when the dose increased. This fact is attributed to scissions in main chain in the carbonyl groups. The carbonyl index was determined by ration A1771/A758, where A758 is the absorbance of angular proportional to the amount of polymer, and not change during irradiation.

! A1771 is the absorbance characteristic of carbonyl groups, \jC=0. The trans- 1 mittance decreased when DUROLON is irradiated because the chromophors

organic radicals are formed in the radiolysis. On the other side, the transmittan­ce increases after irradiation indicating the reactive species are released from polymeric matrix traps slowly. The NMR and EPR spectra showed the recom­bination between fenoxi and fenil radicals. The polymeric radicals that no recombination it became trapped in polymeric matrix and are responsible for undesirable yellowness.

Stability of Durolon

The radiolytic protection of DUROLON was analyzed relating to several additives and different concentrations. Only two national additives using for protect polymers of UV effects and thermo oxidative reactions are efficients to the radiolytic protection. One is the quencher A and another is the radical scavenger B at 1% of total weight.

The films of DUROLON containing 1% of A and B additives and without additives were irradiated with 30 kGy. The protection coefficient (PC) and the energy capture factor (ECF) of additives, the degradation degree (G) and 10*/ Mv of DUROLON are showed in Table 1.

TABLE 1. Radiolytic Protection of DUROLON Using Additives

ADDITIVE lOVMv PC(%) ECF(%) G

WITHOUT 71.0 16.7A (1%) 62.6 82.0 82.2 1.1B (1%) 62.8 77.4 77.6 1.5AB (1%) 62.2 92.7 92.9 0.4

The additive A shown to be more effective to the radiolytic protection than additive B. It suggests that the scissions on DUROLON occur predominan­tly by mechanism of molecular excitation migration by main chain. The mixture of additives AB confer the best radiolytic protection, 92.7 %. The degradation degree decreased of 16.7 to 0.4. It was also observed the occurrence of synergistic effect in this mixture. Therefore, the mechanism of synergism involves the protection of additive B (radical scavenger) by additive A (quencher) by a mechanism of quenching.

25

Conclusions

The medical supplies made by national polycarbonate, DUROLON, can be sterilized by gamma rays without undesirable yellowness.

Three types of national industry are benefited with the success of this research: polycarbonate, medical supplies and additives makers.^

■ CUODODS/

APLICACIONES AMBIENTALESDELPROCESAMIENTODE POLIMEROS POR RADIACION

A. B. LugaoInstitute for Energy and Nuclear Re­search, IPEN-CNEN/SP, Sao Paulo, Brasil.

L Presently, IPEN is engaged in many industrial developments of irradia­ted polymers. It has been focused mainly the advantages of radiation processing products in connection with quality and specially properties. However, radia­tion processing of polymers offers a range of environmental benefits. It can be easily understood because is a cold process, solvent and peroxide free.

This paper describes briefly the IPEN installations for polymer proces­sing and the present research lines with their environmental significance.

PRESENT RESEARCH LINES ENVIRONMENTAL IMPORTANCE

formulation for wire and cable

heat shrinkable tubing and packing

curing of coatings*

vulcanization of natural rubber latex*

curing of composites

less scrap and less energy consumption

less scrap and less energy consumption

solvent free and less energy consumption

sulfur free and less energy consumption

solvent free and less energy consumption

* These subjects are deeply covered in others papers from IPEN.

It is worthy noticing that the common point among these processes is that all processes are energy savers. This is probably the most important environ­mental character of radiation polymer processing.

It is presented also the energy consumption comparison between conven­tional and radiation processing in actual Brazilian processing conditions. The results showed the right dimension of radiation processing energy savings." I

ctcwcd&'nvited Paper

DEGRADACION RADIOINDUCID A DE COMPONENTES DE MADERA

C. ChuaquiAECL Research. Winnipeg, Canada.

^Information is given on the composition of wood, their general characte­

ristics and uses in industrial processes. The presentation continues with the analysis of the chemical characteristics of lignin, a very stable component of wood, and its reaction-induced reactions. A discussion on the possibility to use ionizing radiation as a means to deal with certain pulping wastes follows. "I

Invited Paper

USO DE TRAZADORES RADIOACTIVOS Y MEDIDORES NUCLEONICOS PARA LA DETERMINACION DE PARTICU- LAS CONTAMINANTES TRANSPORTADAS EN AGUA

P. BrissetCommissariat a L'Energie Atomique, Centre D'etudes Nucleaires de Saclay, Gifsur - Ivette, France.

L The first experiments with radionuclides in the field of earth sciences were made more than 35 years ago.

This period has seen the birth and the development of methods and technologies and their confirmation by a great number of experiments.

In this lecture, we will present the methodologies and the possibilities of the two great families of radioactive tools used in the field of dynamic sedimen- tology and especially in the field of suspended particles mechanics.

The radioactive tracers to study the mass transferts in the environment, or inside various industrial plants such as water treatment plants:

* suspended load sediment transport in sea or rivers (coastal engineringpebbles or sand exploitation,......)

* urban and industrial wastewater or dredge materials dumpings in open water areas (pollution, management and optimization of dredging acti­vities)

* residence time distribution inside industrial plants (water treatmentplants, dumping pipes,...... )

27

The nucleonic gauges are designed for measurement, directly in-situ, of the concentration of suspend or deposited sediment or particules

• management and optimization of dredging operations• process control• control and management of dams voidance• measurement of sediment concentration during river floods in

arid areas

The methods an tools based on the use of radioactivity are the comple­ment of classical methods as well in laboratory as on the field. They are giving essential informations to solve the problems in the field of enginering and management of coastal or estuarian areas, rivers and water treatment plants."]

NIVEL DE DESARROLLO EN CHILE DE TECNICAS CON TRAZADORES APLICADAS AL MEDIO AMBIENTE

N. H6resi.H4resi Asociados S.A.C., Santiago, Chile.

E In Chile, most of the radioactive tracers techniques had been developped at the «La Reina>» Nuclear Center, because of the research laboratories and modem set of instruments that includes an RECH-1 experimental reactor. Today, consulting groups as ours, have started working in this field.

This work consits of two different parts, one done in collaboration with the Nuclear Center, and another done exclusively at the Center's laboratories.

The results obtained during the study of dispersion area of river pollu­tants, using radioactive and non-radioactive tracers, are presented in this report. Flow and dilution capacity measurements of the Mapocho river (10 m3/S), a spillway channel for the domestic sewage waters of Santiago, are also included.

Different works done by Chilean mining industries, in order to optimize processes that reduce pollutants's discharge, use a constituent element of an irradiated mineral as a radioactive tracer, to obtain residence time distributions and flow patterns in grinding mills, flotation cells and columns, electrolitical cells and leaching tanks.

The determination of parameters as velocity and dispersion, the mode­lling of river pollutants's transportation, and the study of flow in sewage waste treatment ponds are other tracers applications discussed here.

Finally, the trends for tracers's use in Chilean pollution studies are exposed here. ~j

28

■ OflWDSS

DETERMINACION DE ZONAS DE FILTRACION EN ESTAN- QUE NATURAL DE ALMACENAMIENTO DE AGUA Y SU POSIBLE EFECTO EN EL MEDIO AMBIENTE

O. Durin, F. DfazComlsl6n Chilena de Energfa Nuclear, Santiago, Chile.

^This is a report on the applied methodology used by the Tracer Labora­

tory at the Nuclear Chilean Energy Commission, for the location of filtration zones in a discharge reservoir of Maitenes Electrical Center Station.

The generation of electric energy, by means of flowing waters require of the storage of this element, for which purpose natural reservoirs are sometimes used. Those reservoirs had the wall and bottom covered with waterproof materials in order to avoid filtration or significant leakage. These kinds of problems had an important effect over the electric generation and can pose important risks to the environment.

When cause of the leakage is well known, it is necessary to detect the filtration zones and proceed to repair. The use of Radioactive Tracers enables these zones to be identified.

In order to use the apropriate radiotracer, absorption tests were made for 1-131 and Au-198. The last one was selected in order to avoid the watershed contamination.

The later study with the selected radiotracer was conducted in order to determine the specific filtration point of the water reservoir.

The results show that the safe use of a specific tracer without damage to the environment, optimize the use of the water resource and contribute to the prevention of undesirable changes in the field. 1

iDETERMINACION DEL TIEMPO DE RESIDENCIA Y ESTU- DIO DE LA DISTRIBUCION DE LA CONCENTRACION DE UN RADIOTRAZADOR EN UNA LAGUNA DE OXIDACION

J. Duque, O. Espinosa, G. Herrera Institute de Ciencias Nucleares y Ener- gia Alternatives, INEA, Santa F6 de Bo­gota, Colombia.

L This work permitted to study the residence time in an oxidation pond in a company of petroleum in Colombia, and it makes a first approximation of the radiotracer concentration distribution, and identify both dead and preference zones of flow. In the previous work, 1-131 was used in the form of sodium iodide, which was injected instantaneously at the entry of the pond.

29

The oxidation pond which is in study, has an average of 1.0-1.2 meters deep, a volume of 5(X),000 cubic meters approximately and a flow rate of 1.3 cubic meters per second and it is the last of trie series of four ponds that receive the wastewaters of a petroleum company.

Three detectors of Nal(Tl) were placed in the discharge pond. From a boat, a continuous monitoring was made for the preliminary evaluation of the distribution of the concentration and identifying dead zones and flows with their path curves.

The work resulted as a consequence of clear politics of the petroleum company which looks for conserving the environment and it is worried about the damage for the plants and animals living in the pond. The results of the this work has been successful! for the knowledge of the pond dynamics, to make the corrections, besides to take advantage of its potentials and to improve the sampling operation in order to determinate the contents of oxygen and conta­minants before discharging to the environment.^

■,/ APLICACION DE RADIOTRAZADORES A LOS ESTUDIOS

SOBRE REMOCION DE METALES PESADOS EN AFLUEN- TES LIQUIDOS

J. BorrotoInstitute Superior de Ciencias y Tecno- logfa Nucleares, La Habana, Cuba.

Llhe waste licour WL that is generated in the acid leaching of laterite for nickel and cobalt sulfid concentrates production is one of the principal contami­nation sources of seawaters at the Moa Bay. The feasibles solutions of this problem has the inconvenient that the world known technological process for the treatment of similar liquid wastes can increases the plant operational costs at a 25%. For an economic descontamination of this waste and the recovery of its metallic valours is studying and scheme of treatment based in the neutrali­zation with naturals products. A novel chemical approach that use a flocculant obtained from the bark of Pinus cubensis (Griseb), species that grow and its commercially exploted at the northwester of the east region of Cuba, is proposed like a third stage of the licours proccesing scheme. The researches combining the use of radiotracers MMn y “Co with the techniques of spectrophotometric analysis for iron and nickel allowed us to determine the percent of remotion and to define the principals variables for the scaled. The present of four phases: Mn203, Mn30. y aFe203 y Fe3Q4 in the obtained precipitates is proof. It is feasible to remove and 80% or 85% of manganese or iron, respectively. ''

Key words: Flocculant, heavy metal remotion, waste licour, radiotracers, cobalt-60, manganese-54.

30

TECNICAS DE RADIOTRAZADORES APLICADAS A ESTU- DIOS DEL MEDIO AMBIENTE Y CONTROL EN LA CETESB

S. Nakahira, M. Meciano, A. Martins Cia. de Tecnologia de Saneamiento Ambiental, CETESB, Sao Paulo, Brasil.

[This paper presents the techniques and experiencies acquired during 19 years of Radioactivity Division at CETESB, specially about radioactive tracer application on studies and determination of hydraulic and hydrological para­meters in environmental problems.

The Radioactivity Division of CETESB has been used the radioactive tracers as normal routine application and it has demonstrated to be a accurate and usefulness tool in this environmental field. Among several applications of radio tracer techniques at CETESB we have emphasized in this paper as follows:

Flow-rate measurement in streams, channels, industrial and do­mestic effluents using continues injection of radio tracer;Transit time and longitudinal dispersion in rivers using pulse injec­tion of tracers and monitoring the passage of radioactive cloud at downstream points;Detection of residence time, dead space and channeling using pulse injection method in systems of waste water like anaerobic digestors, tanks and lagoons;Detection of irregular waste water connection at pluvial water drainage channels and pipes;

- Studies of sewage systems performance and dispersion inbodies ofwater;Measurement of bed load transport of sediments in rivers using surface radio tracer labeling; andMeasurements of dispersion plumes and mixing zones in rives, downstream effluent discharge points. *1

MRESPUESTA AL TRAZADO Y MODELACION DE CORRIEN- TES URBANAS

/

R. Moreira, V. Bomtempo, A. Pinto Nuclear Technology Development Cen­ter, National Nuclear Energy Commis­sion, Belo Horizonte, Brasil.

Ci-The Arrudas River flows across Belo Horizonte, the third largest city in Brazil, and receives most of its liquid wastes and shows a highly transient regime over a day's period. A wastewater treatment plant being planned required a sampling scheme that would track the same parcel of water along succesive sampling stations. A radioactive tracer (Br82) was chosen to define time of passages, since high turbidity and excess of suspended solids prevented use of

31

dyes. An instantaneous injection and detection of the response at the four station sites was somewhat trivial.

The sampling stations bracketed individual reaches with quite distinctive hydrographic characteristics. It was realized that with a little more of experi­mental and computational effort a lot of additional information on the stream behaviour could be gained. This paper reports on how these extras were obtained. The first and most immediate of them was the flow rate, calculated by the total count method, using the tracer records.

Flow velocities and dispersion coefficients at the distinc reaches were determined via model fitting. The one dimensional dispersion model was employed; however with the exception of the first reach, the recorded tracer signals were responses to an impulse but rather to those arbitrary signals recorded at the entrance of the reach. Hence a deconvolution procedure had to be applied which used a nonlinear least squares algorithm to match the model impulse response function h(t) to the entrance and exit signals, x(t) and y(t):

y (t) =/ h(T) x (t-t) dTJo

Where h(t) is the solution of the dispersion equation with the appropriate boundary conditions at the open ends of the reach. The entrance and exit signals are Fourier transformed, which changes the cumbersome integration above into a much easier product. The model parameter values thus determined reflected the physiographic traits of each reach.

By means of BOD and DO analyses combined with the information on the time of passages and the associated dispersion, the self-purification characteris­tics could be evaluated (the deoxygenation constant K, of the Streeter-Phelps model) without recourse to a non realistic plug flow assumption.

The transport model was checked by cross-correlation of the physicoche­mical parameters at different stations and in fact even predicted the time of passage of the diurnal flow rate transient. Thus, although not exactly the same thing, the derived mass transport model can be also used for a fairly good determination of the hydraulic crest movement in the composite reach - a much needed information in flood propagation prediction in urban streams. J

■ Ci^ToDoeto

APLICACION DE TECNICAS ISOTOPICAS EN LA CARAC- TERIZACION PRELIMINAR DE LA CONTAMINACION DEL ACUIFERO DEL GRAN SANTIAGO

A. Silva*, C. Salazar*, A. Merino*, A. Pollastri*** Direccidn General de Aguas, MOP, Santiago, Chile.** Comisidn Chilena de Energia Nuclear, Santiago, Chile.

T In Santiago City, is concentrated almost 5 million inhabitants and 50% of

32

country industrial activity. Naturals channels present a high grade of pollution due to direct discharges of waste waters without previous treatment. The volume of these discharges to the acquifer is unknown.

The most significatives industrials area from point of view of hydric pollution are: nourishing and agroindustrial, metallurgy-metalmechanic, che­mical, leather and textile. The majority of the industries discharge their wastes to sewerage system, melting them with domestic wastes.

Actually four samplings have been done (July-92, October-92, January-93 and April-93), considering both superficial and underground waters; embra­cing the whole acquifer of Santiago. Aproximately 300 samples have been tested for physic-chemical analysis (macroelements, nitrates, nitrites, copper and iron) and isotopics (D, 018) which correpond them to 55 wells and 20 superficial points. Additionally exists other physic-chemical information from recently studies realized.

The objective of this study is to identify, in general terms, the source, extension and possible propagation of contaminant elements, which are incor­porate to the acquifer. The aim of study is to carry out a sectorization of contaminated areas according to their characteristics, quantity and extension, based on isotopics and standard techniques for a determinated period.

On the basis of the results obtained, a specific monitoring networks is spec ted to be formulated to propose recommendations for the prevention, control and vigilance of detected and prevented problems.j

■ e^^oooqr EVALUACION DE LOS PROCESOS DE TRANSFORMA-

CION DE PARTICULAS SOLIDAS EN PLANTAS DE PRO- DUCCION DE CEMENTO MEDIANTS EL USO DE TRAZA- DORES RADIOACTIVOS

C. SebastiinInstitute Peruano de Energia Nuclear IPEN., Lima Peru.

! Transformation and modification of solid materials in the cement indus­try requires movement. Radionuclides techniques can greatly help in unders­tanding these mechanism. Their advantage lies in the contactless measurement of radioactively labeled flows of materials by the radiation emited, even though thick walls of equipment or rigorous process conditions (high pressures or high temperatures).

It has been datermined the retention time distributions in one of the rotary kiln systems at «Cemento Andino» plant in Tarma-Peru, by using fine grain powder of La-140 in the form of La203 as a radiactive tracer. In this way, the isotope helped to establish a subdivision into the various process zones. This information is important in discussing the effects of the heating-up rate on clinker formation and quality of products.

The radiation measurements were performed with four scintillation detectors installed outside the kiln in different parts of the total lengh, and at the

33

end of cooler. The measured counting rates were recorded as a function of time by means of recording instrumens.

Even though the highests concentrations of residual radiactivity at the end of determinations in different parts of the plant were found to be below the permissible values, it is important to take special attention in regards to transportation and handling of radioactive tracers such as Lantanum 140. It has a half life of 40 hours, and emit gamma radiation with maximum energy of 1.60 MeV with 100% of intensity. J

■j DETERMINACION DE RECAMBIO DE AGUAS SUBTERRA-

NEAS EN ABADIA DE GOIAS. ESTADO DE GOT ANA. FOR APLICACION DEL METODO DETRITIO MARCADO ARTI- FICIALMENTE.

D. Poll*, P. Aoki*, V. Lepki*, S. Saad**, L. Araujo**, G. Pedroso***lnstituto de Pesquisas Energdticas e Nucleares, Sao Paulo, Brasil. **Comissao Nacional de Energia Nu­clear, Rio de Janeiro, Brasil.

[_ The movement of the moisture in the unsaturated zone can be monitored using both environmental and artificial tritium. Artificial tritiated water was used as a tracer for determining the groundwater recharge in the radioactive waste disposal site at Abadia de Goids-Goiania. Groundwater recharge is the input rain into the saturated zone and is essential for urban water supply, agriculture and resource evaluation.

The region studied is located in the central part of Brazil. The area is covered by lateri tic soil. The climate is semi-arid tropical with mean temperature of 23.2°C, mean annual humidity of 66% and mean annual precipitation of 1520 mm. Almost all of the total rain precipitation, 75%, is concentrated between november to march. The driest time is from june to august with precipitations corresponding to 2% of the total amount.

Injections of tritiated water were made in july 1991 at depth of 50 cm below the surface out of the root zone of vegetation. Five points injections were made at 10 cm radial distance in the form of a cross. In each point was injected 2.5 ml of tritiated water with concentration of 5.55 x 10*Bq/ml. Soil samples were taken with hand auger after four, nine and twelve months from injection. For extraction of moisture, the soil samples were distilled in a vacuum system and the estimation of tritium was carried out by liquid scintillation counting. The recharge was calculated from tritium and moisture profiles.

The results have shown a good correspondence bew teen the soil the groundwater recharge. The highest recharge obtained was 30.07 cm and the lowest one was 11.63 cm. The mean value for the recharge was 21.32 cm, corresponding to 14.36% of the precipitation in the period of july 1991 to july 1992. It was obtained a value of 30% for the tracer recover that is considered good for this kind of work. ~|

34

cumoics.!/■

USO DE MZn COMO TRAZADOR RADIACTIVO EN ES- TUDIOS DE BIOACOMULACION DE ZINC FOR POECILIA RETICULATA

W. Malagrino, B. Mazzilli ComissSo Nacional de Energia Nuclear, Sao Paulo, Brasil.

TjTte bioaccumulation of zinc by Poecilia Reticulata from the water as well as the elimination of the metal previously absorbed were determined by using “Zn as radioactive tracer.

The exposure time varied from 5 days, short term experiment, to 30 days, long term experiment. 'The results obtained show that the absorption and elimination of zinc by Poecilia Reticulata is slow, 30 days being necessary for the elimination of 70% of the previously absorbed zinc. T

Invited Paper

TECNICAS ANALITICAS NUCLEARES EN EL MONITORED E INVESTIG ACION EN CHILE: UNA VISION DEL ESTADO ACTUAL Y PERSPECTIVAS FUTURAS

N. GrasComisidn Chilena de Energia Nuclear, Santiago, Chile.

I An outline is given for nuclear analytical techniques laboratories and how to find opportunities for the application of these techniques in some chemical measurements in environmental studies that are becoming a particular case in point with the public's and goverments institutions, such as ministries of health, industry, agriculture and the food export sector are growing awareness about the environment.

Goverment research institutes often have access to one or more nuclear trace element analysis techniques and they can be used as complementary analytical techniques in interdisciplinary environmental studies. Some advan­tages of these techniques are: non destructivity in some cases, high degree of accuracy, independent of sample types, reliability, posibility for samples with sizes up to few grams to be analyzed which contributes to representability, sensitivity, an important aspect when only limited material is available (e g. air particulate matter). The tecniques discussed are nuclear activation analysis (NAA), delayed neutron countring; energy dispersive X-ray fluorescence (ED- XRF) and particle induced X-ray emission (FIXE).

This lecture outlines how opportunities can be found as part of interdis- • ciplinary team for environmental research are discussed. *T

35

An overview of current applications are discussed given examples of the studies. Future prospects are outlined.

■ <L°i}aX£5i/el desarrollo de las tecnicas nucleares anali-

TICAS EN EL PROGRAMA ARCALIV Y SU CONTRIBUCION AL ESTUDIO DEL PROBLEMA DEL MEDIO AMBIENTE

M. Cohen*, N. Gras**, H. Vera-Ruiz*»»*Comisi6n Nacional de Energia Atdmica, Buenos Aires, Argentina. **Comisi6n Chilena de Energia Nuclear, Santiago, Chile.***Organismo Intemacional de Energia Atdmica, Viena, Austria.

1 The evaluation of the project Nuclear Analytical Techniques (ARCAL IV)

in terms of activities performed, techniques used and subjects of interest, are described. The applications to the study of environmental problems are specifically detailed.

The results of two different intercomparison runs, carried out as put of the Coordinated Research Programme of Nuclear Analytical Technique is the Analysis of Food stuffs and Agricultural Products are received. The conclusions is that the analytical quality has significantly in proved in the last years, this fact being are of the must relevant contribution of the ARCAL IV project to the development of the nuclear analytical tecniques in the Latinamerican region. In addition, some of the countries are now actively working in the preparation regional reference materials, in connection with one of the main objectives of the project.^

■ (LWX)(s>bV DESARROLLO DEL AREA AMBIENTAL Y SANITARIA EN

EL INSTITUTO TECNOLOGICO DE COSTA RICA

G. CastroDepto. de Quimica, Institute Tecnoldgico de Costa Rica, Costa Rica.

l_This is a summary of what the Institute Tecnoldgico de Costa Rica (ITRC) is doing in the environmental area.

f!Costa Rica is a tropical country, with a great diversity of flora and fauna,

located within a small geographical area. It has the natural resources and the human potencial to develop sustainable models. Because of what it is necessary to have studies that would give base to sustainable development based on long term planification policies.

As well as other countries in Latin America, Costa Rica has suffered an accelerated deterioration of its resources in the last decades. Therefore some

36

sectors are working to promote a gradual transformation of economical and social structures that would allow the establishment of sustainable model of development.

The ITCR is a technological University, devoted to contribute significati- vely to the development of science and technology. It participates in activities aimed to improve the quality of life of the Costa Ricans. ITRC has developed some research and-teaching areas that include: Manageament of tropical ecosys­tems, Environmental education. Occupational health, Pollution and environ­mental sanitation.

Undergoing projects include:«Quality control of drinking water for some communities in urban and rural areas®, "Evaluation of drainage water®, "Characterization of industrial waste waters®, "Design and evaluation of water treatment plants®, "Acid rain due to the Arenal volcano activity® and "Atmos­pheric corrosion map for Costa Rica®.

Traditional standard methodes ( ASTM, APHA, AWWA and WPCF, Standard Methods for Examination of water and wastewater) have been used in the evaluation of the chemical parameters involved in such projects.

Through a multidisciplinary group, ITCR is presently trying to colaborate an action plan to incorporate the nuclear technology in several areas of research and development.

Also, ITCR is in the process of establishing a Research Center in Environmental Protection (CIPA ). Wich is expected to give answers to the present necessities. The goal of such center would be to work in sustainable development.

ITCR is very interested in developing and training personel in the field of industrial applications of isotopic and radiation techniques, to monitor pollu­tion and improve the quality of the environment. These new techniques are of special importance and can be used as another tool to improve the quality of the environment.

^RADIONUCLIDOS Y ELEMENTOS TRAZA DE MUESTRAS AMBIENT ALES EN BRASIL

C. Munita, I. Cunha, R. Paiva, R. Figue- reidaComissSo N acional de Energia Nuclear, Sao Paulo, Brasil.

fin the last years there has been an increasing interest in various elements present in the environment and their possible effects on human health due to the increase of pollutant emissions from fuel combustion, automobile exhaust and industrial activities.

The pollutants can be transported across long distances from their emis­sion source, removed from the atmosphere and deposited in the biosphere and hydrosphere by a number of mechanisms. They can get into the human body by

37

means of ingestion of contaminated food, air inhaling or by direct absorption from the biosphere.

Artificial radionuclides, such as cesium-137 and strontium-90 are produ­ced regularly in nuclear power plants and reach the environment by means of effluent discharges, nuclear weapons tests and from accidental releases as the Chernobyl accident. These two radionuclides are important due to their nuclear and chemical characteristics. They have long physical half lives and high fission yields. Besides they have physiological and chemical behaviour similar to K and Ca, respectively, that are important elements from the biological point of view. These radionuclides can enter the human population by several pathways and one of them is the marine environment.

Considering these problems and the lack of information concerning our country, it is relevant to investigate the trace element contents as well as radionuclide levels in environmental samples, such as aerosol and marine samples.

Aerosol samples were collected in the city of S3o Paulo using a Dichoto­mous Sampler that fractionates suspended particles into two size fractions, 2.5 to 10pm and less than 2.5pm on two37mm teflon membrane filters. Aluminium, Br, Ca, Ce, Cl, Co, Cr, Fe, K, La, Mn, Na, P, Pb, S, Sb, Sc, Se, Si, Sm, Th, V, and Zn contents were determined by ED-XRF and INAA.

The elemental concentration data were analysed by means of linear correlation coefficients, enrichment factors and absolute principal component analysis. The main aerosol sources are marine, re-suspended soil, fuel oil combustion, phosphatic rocks, refuse incineration and residual high temperatu­re processes.

In order to determine the radionuclide levels in our country, marine samples (seawater and fish) were collected from 7 points of the Brazilian coast from State of Rio Grande do Sul (southern coast, 32° ll'S) to State of Para (northern coast, 00°26’S).

For seawater analysis, cesium was preconcentrated from 100 liters of sample using ammonium phosphomolybdate (AMP) and determined by gam­ma spectrometry, while strontium was preconcentrated using sodium carbona­te, purified by iron hydroxide scavenger and stored for 14 days to reach the radioactive equilibrium. Ytrium-90 was separated as oxalate from Sr-90 and counted in a low background Geiger Muller detector.

For fish analysis, the edible part (2 Kg) was weighed and dried at 110°C for one week and later the temperature was gradually increased up to 450°C until ashes were obtained. Ashes were counted in polyethylene pots in a hyperpure Ge detector to determine Cs-137 contents. Further, they were submitted to wet digestion and to tire same procedure employed for seawater in order to determine Sr-90.

The main fish species consumed by our population, such as sardine, ballisted, weak fish, dog fish, mullet, saw fish, red, mackerel scad, Brazilian croakar and white grunt were analysed. Cesium-137 and strontium-90 radioac­tivity levels were typical fallout deposition values and were lower than the values obtained in the North hemisphere.

38

The authors wish to acknowlegde finantial support trom FINEP, FA- PESP, CNPq, the International Atomic Energy Agency (Research Contracts n 4957 and 5245) and COPESP.

/nvited Paper

TECNICAS ANALITICAS NUCLEARES: HERRAMIENTAS PARA EL ESTUDIO DE LA CONTAMINACION DEL AIRE URBANO

S. LandsbergerUniversity of Illinois, Department of Nuclear Engineering, USA.

L Over the last few decades, the concentrations of many trace metals in the atmosphere have risen dramatically to the point where industrial and automo­bile emissions now dominate the natural biogeochemical cycling in many urban environments.

There have also been many studies suggesting that increased urban air concentrations of toxic metals, such as chromium, arsenic, cadmium and lead, have been associated with cancer risk factors. Airbone particulate matter is a complex pollutant in which needs reliable analytical methods to measure the elemental concentrations of urban air. Besides good trace element analitycal techniques, proper sampling methodologies and the use of source-receptor models are needed. Nuclear analytical methods such ais neutron activation analysis, X-ray flourescence and particle induced X-ray emission are ideally suited to be implemented in research and routine air monitoring programs, particularly in urban environments. This talk will emphasize the importance of these methods, their usefulness in several programs conducted in the United States and how critical they are in using source receptor models including factor analysis, source apportionment and chemical mass balances, - j

■ CL <WQS1CUANTIFICACION DE SULFATOS EN LOS AEROSOLES ATMOSFERICOS DE SANTIAGO DE CHILE MEDIANTE LA TECNICA DE DILUCION ISOTOPICA.

M. Prendez, J. Ortiz, S. Zolezzi Fac. de Cs. Qufmicas y Farmacduticas, Universidad de Chile, Santiago, Chile

[ Sulfates are found in the atmosphere as a result of the transformation that undergoes here through the process of gas-particle conversion.

Sulfates thus ocurring in atmospheric aerosol are potentially dangerous for human health, for terrestrial and aquatic animal life, and for materials.

39

Sulfates may represent up to 50% at the fine fractions of aerosols in urban and suburban atmospheres.

The purpose of this study is to show the results obtained for aerosols in Santiago, Chile, through the analytical technique of isotope dilution.

Quantifications were done on total particulate matter, that is, smaller than 45 pm, and on a highly breathable fraction (smaller than 3 pm) separated in six fraction.

The mean concentrations for total particulate matter are about 30 pg m- 3 downtown in wintertime. In the suburbs the concentrations reach 22 pg m-3.

The mean concentrations for the breathable fraction in the urban section reach about 15 pg m-3, with some values as high as 30 pg m-3, in the winter­spring period. In the spring-summer period values fall to one-half or one-third of the winter values.

Experimental evidence shows that sulfates concentrate in the smaller than 2.5 pm fraction.

The detailed study of the smaller than 3.0 pm fraction shows that sulfates concentrate in the fraction smaller or equal to 0.41 pm, making up 23% of aerosols of that size.

In Chile there is no regulatory standard for this pollutant, but a compa­rison of the results with the California standard (25 pg m-3) shows that sulfates constitute an actual health risk for the population of Santiago.^

■ cunwo^oV ESTUDIO DE PARTICULASTRANSPORTADAS POR EL AIRE

EN SANTIAGO, UTILIZANDO METODOS QUIMICOS Y NUCLEARES

P. Toro*, H. Sandoval*, R. Morales*, M. Dinator*, C. Romo*, V. Cassorla**, X. Rojas**, S. Marin**, S. Olave**, C. Agui- la**, N.Gras**, S. Cornejo**.*Facultad de Ciencias, Universidad de Chile, Santiago, Chile.**Comisi6n Chilena de Energia Nuclear, Santiago, Chile.

^.Nuclear (PIXE, NAA, ID) and chemical (AAS, IC) analytical methods have been applied to the multielemental and some ionic characterization of aerosols from Santiago, Chile. Gravimetrical determination was also perfomed.

Here we present preliminary results from a set of samples collected in an urban site during nine days in the winter season of 1992.

The main objective in this stage has been to compare the capability, sensitivity of different techniques in order to distinguish the most significant elemental contributions of the aerosol in the city.

40

The collection equipment was a two stage SFU (Stacked Filter Unit) unit with polycarbonate filters separating in modes coarse (15-2.5 pm) and fine (<2.5 pm).

The elements determined by each technique are the followings

FIXE : Al, Si, Cl, K, Ca, S, Cu, Zn, Ti, Mn, Fe.NAA: Sb, Cu, As, Br, Cr, Co, Fe, CL Na, V, Al, Mn, Ca.AAS : K, Pb, Na.

In addiation the following ionic compounds were determined:

IC : sulphate, nitrate, cloride.ID : sulphate.

The overlap of a set of commun elements has allowed a comparison of sensitivity.

These results obtained from the same filters studies by five different analytical techniques, represent the first multidisciplinary study of aerosols in Santiago. Thus allowing the determination of a broad profile including both elements and compounds in atmospherical urban aerosols. The gravimetrical results show a cyclic dairly fluctuation. J

m/INTERCOMPARACION DE CONCENTRACIONES ELE-

v MENTALES EN AEROSOLES ATMOSFERICOS DETERMI- NADOS FOR FIXE Y NAA

V. Cassorla*, X. Rojas*, N. Gras*,L. Chuaqui*, M. Dinator**, J. Mora­les**, F. Llona** and C. Romo** *Comisi6n Chilena de Energia Nuclear, Santiago, Chile.**Universidad de Chile, Santiago, Chile.

[two analytical methods PIXE (Proton Induced X-ray Emission) and NAA (Neutron Activation Analysis) were used to analyze atmospheric aerosol sam­ples collected in the city of Santiago, Chile. The main objective of this work was to compare both techniques in their application to environmental problems.

The aerosols were collected in Nucleopore filters with a two stage SFU (Stacked Filter Unit) classifying the samples in coarse mode (aerodinamic diameter between 15 y 2.5 pm) and fine mode (< 2.5 pm). The campaign was carried out during nine days of the month of July (1991). The SFU equipment was installed at the La Reina Nuclear Centre, an Andes foothill sector, a semi-urban area.

The samples were analyzed firstly by PIXE with 2.2 MeV proton beams supplied by Universidad de Chile's isocrone cyclotron accelerator and then by NAA in the nuclear reactor RECH-1 of the Comisidn Chilena de Energia Nuclear. PIXE allowed the determination of 12 elements: Al, Si, S, K, Ca, Ti, Cr,

41

Mn, Fe, Cu, Zn and Pb, on the other hand by NAA15 elements were determined Na, Al, Cl, Ca, Sc, V, Mn, Fe, Co, Cu, Zn, As, Br, Sb and Au. Both techniques detected 21 different elements in the aerosols, including trace and major ele­ments. There is a set of six common elements, Al, Ca, Mn, Fe, Cu and Zn, which allowed us to perform intercomparison runs.

The elemental concentrations of the common elements in the coarse mode, showed good agreement between both techniques. In the case of the aerosols collected in the fine mode, the agreement is not so good due to the lower mass collected.

This work shows a good complementation of both methods covering a wide elemental spectrum which includes natural origin elements and others, known as anthropogenic elements. The later being of interest for health popu­lation i.e. S, As and Pb."]

ESTUDIOS DE POLUCION EN PARAGUAY: CONCENTRA- CION DE ELEMENTOS EN LA ATMOSFERA, USANDO TECNICAS ANALITICAS NUCLEARES RELACIONADAS

V. Romero de Gonzilez, Z. de Dfaz,J. CabelloComisidn Nacional de Energia Atdmica, Asuncidn, Paraguay.

[The main objective of this research is the study of the elemental compo­sition (sulphur and heavy elements) of air particulate matter in the lower atmosphere of the city of San Lorenzo an residential area near Asuncidn.

In order to compare the results on airbone particulate pollution in the city, sampling was also perfomed in two rural stations, at Pozo Colorado and Jhere, respectively 430 and 150 km from Asuncidn. The concentrations obtained in the latter are considered as base line measurements.

Samples were collected on Millipore type Ha filters at a flow rate of 10 L/ min provided by a Andersen Series 110 constant flow air sampler. The loaded Millipore filters are analyzed with secondary target x-ray flourescence. XRF offers a very interesing approach so environmental analytical problems as it enables the simulteneous detection of several trace elements.

The energy-dispersive x-ray fluorescence system includes a Mo-anode x- ray tube and various secondary targets (Fe, Cu, Zr and Mo). The excitation and the resulting flourescence radiation in collimated at 45" with respect to the sample. A total reflection unit is also attached to the x-ray tube. Characteristic x-rays are measured with a liquid nitrogen cooled Si(Li)-detector. After pulse processing the spectra are accumulated in a Canberra S 100 multichannel analyser card installed in a IBM compatible 386 PC. Spectrum evaluation and quantisation are done with the AXIL-QXAS software, i

42

_ . CW%0M3

VARIACION ANUAL DE CONCENTRACIONES DE Si, Ca, S, K EN AEROSOLES ATMOSFERICOS DE TEMUCO, CHILE, DETERMINADAS FOR FIXE

R. Figueroa*, D. Caro*, R. Morales**, M. Dinator***Departamento de Fisica Universidad de la Frontera, Temuco, Chile.** Facultad de Ciencias, Universidad de Chile, Santiago, Chile.

L Particulate mailer in the size range below 15 pm have been collected with a two stage SFU (Stacked Filter Unit) during several months in years 1990,1991 and 1992. The sampling unit, located in the university campus in downtown Temuco, separated the aerosol in two modes: coarse, from 15 to 2.5 pm and fine below 2.5pm. Nuclepore filters of pore sizes 8.0 pm and 0.4 pm were used. Air volumes of around 10 cubic meters were sampled in periods of about 24 hours. Total mass in each filter was determined, prior to elemental analysis by FIXE (Proton Induced X Ray Emission). Which was performed at the nuclear Physics Laboratory of the University of Chile in Santiago, Proton beams of 2.2 Me V were provided by the isochronous cyclotron.

The gravimetric measurenment show that concentration of airborne particulate matter increases during winter periods, both in the coarse and fine modes. This is something that is also observed in the pullated cities like Santiago and Mexico, where temperature inversion cases are frequent. Total mass concentration of coarse and fine matter reached values in the range of 200 pg/ m3 in some the sample days.

FIXE allowed detecction of eleven elements in the aerosols: Al, Si, K, Ca, Ti, V, Mn, Cr, Fe and Cu. Four of these elements have been selected for this study. Si, Ca, S and K. The first two are typical soils components while the others can be tracer to anthropogenic origin, it is observed that in general the fluctua­tions in silicon and calcium concentration, in coarse and fine modes, follow similar trends. Instead, sulfur and potassium increments in winter months, are mostly in the fine mode. This could be due to larger concentrations of sulfur compounds from vehicle emissions trapped by temperature inversion episodes, and potassium compounds emitted from wood burning for heating, -j

v COMPOSICION ELEMENTAL DE TRES ANILLOS DE LA CUENCA DEL AMAZONAS, MEDIDOS PORTECNICAS FIXE

J. Martins*, P. Artaxo*, E. Ferraz**'Institute de Fisica, Universidade de Sao Paulo, BrasiL**CENA-Centro de Estudos Nucleares na Agricultura, Sao Paulo, Brasil.

L There is very few possibilities to obtain historical records of climate change in the Amazon Basin. The analysis of sediments and tree rings can

43

provide information on anthropogenic induced environmental changes in the Amazon Basin. The dendocronology of tree rings has provided important paleoclimatic information in temperate regions. For tropical regions, the isotopic ratio '-XZ/'KT and 14C dating can provide accurate chronology data. The absorption of trace elements and heavy metals by roots and leaves from the soil or atmosphere can be correlated with ambient pollution and climate variations. The extensive mining activities in the Amazon Basin and the high particulate matter in the atmosphere due to biomass burning are possibly changing the pattern of several heavy metals in the Amazon Basin environment.

The FIXE analysis is being performed in a new dedicated PIXE/RBS 5SDH Pelletron accelerator from the Institute of Physics, University of Sao Paulo. A special irradiation procedure was developed to eliminate the charging of the sample. An 4.8 MeV alpha particle beam is used to enhance the detection limits. The X-ray spectra are analyzed by the AXIL and PIXAN software packages. Thick target corrections are checked with biological reference mate­rials from NIST and IAEA and an accuracy of better than 15% is obtained for most of the detected elements. A special sample preparation technique was developed to avoid contamination during sample preparation.

Three samples were analyzed: Lecythis usitata Miers (Castanha Sapu- caia), Hymeneae sp (Jatoba) and Pimus Caribeae hondurencis. These samples are also being analyzed by carbon isotopes and dendocronology using X-ray absorption at CENA. For the PIXE analyses, the wood samples were cut to a thickness of 7.5 to 23 mg/cm2, allowing the elemental analysis of individual tree rings. It was possible to measure the concentration of 11 elements: Mg, Si, S, K, Ca, Cr, Mn, Fe, Ni, Cu, and Zn. The detection limits were in accord with the expected concentrations in the Amazon Basin trees. We are planning to use a 3 MeV proton beam to measure heavy elements, following with irradiation using a 4.8 MeV alpha particle beam to enhance detection limits for both light and heavy elements. The density data obtained by the X-ray absorption technique will be used to enhance the precision of the thick target corrections. A large number of samples can be analyzed by PIXE allowing mapping the anthropo­genic influences in the Amazon Basin. J

■ Is/analisis elemental de la fraccion soluble e in­

soluble EN AEROSOLES ATMOSFERICOS FOR PIXE Y XRF

M. Romo KrogerFacultad de Ciencias, Universidad de Chile, Santiago, Chile.

[ Analysis on the soluble and insoluble fractions of aerosol material was performed by PIXE (Particle Induced X-ray Emission) at the cyclotron of University of Chile, and by XRF (X-ray fluorescence) at University of Santiago, Sample preparation was by immersing in alcohol a portion of glass fiber filter collected upon high volume flux downtown Santiago. Aerosol was extracted and homogenized by ultrasonic vibration. Then, liquid was filtered through a0.2 pm Millipore filter and the soluble fraction separated. This solution was dried over a Kapton foil, where the resulting solid material was adhered (soluble

44

aerosol sample). Other sample was prepared with the unfiltered liquid, in the same way of prior sample (total aerosol sample).

On the base of PIXE and XRF results, the group of elements Si, Ti, Pb have almost nule solubility. Na, Cl, S and Br are me most soluble elements. The estimated (soluble/total) ratios for the Santiago aerosols are: 1.0 (Na), 0.5 (Al), 0.0 (Si), 0.7 (S), 1.0 (Cl), 0.3 (K), 0.2 (Ca), 0.0 (Ti), 0.2 (Fe), 0.3 (Cu), 0.3 (Zn), 0.8 (Br), 0.0 (Pb)

The solubility trend of elements is similar to the obtained for rain water from Florida State, U.S. (Darzi et al., Env.Sci. Tech.15,1981, p.354), although Pb, Ca and K have different behaviour. Florida samples were prepared in a similar way, on Mylar foils and analized by PIXE.

Rain water samples have been collected in Santiago and soluble and total fraction separated, as described for aerosol samples. Solid samples on thin foils are good for fluorescence analysis (PIXE and XRF) and other techniques like microscopy (optic and electronic). J

■ 04%)%%%/ANALYSIS DE AEROSOLES ATMOSFERICOS AMBIENTA-

LES FOR TRXRF

V. Poblete, P. Castillo, R. Figueroa*,J. Gilvez.Comisidn Chilena de Energla Nuclear, Santiago, Chile.* Universidad de La Frontera, Temuco, Chile.

L In this study, adaptation of Total Reflection X-Ray Fluorescence Techni­que (TRXRF) to the analysis of traces in atmospherics aerosols from the city of Temuco is reported. The samples were taken after the last eruption of Lonqui- may volcano.

The analysis by this technique, was mainly introduced by two groups (1 2). The great success of this technique is owing to the following advantages: the conventional XRF and the Total Reflection System, whose geometry allows the multielemental analysis, with low detection limits in the ppb level, using only 5 pi of sample solution. This fact turn this technique into a competitive one related to other traditional methods, like Atomic Absorption Spectrometry (AAS), Plasma Atomic Emission Spectrometry (ICP) and Neutron Activation Analysis (NAA), with the additional advantage that it is multielemental and short measurement time. The disadvantage consists in that it uses quartz sample holders, which are expensive and must be cleaned and purified, after each analysis with hight purity (ultrapure) reactives, in order to avoid the contamination of the sample holder surface.

11 elements were analysed simultaneously, with concentration ranks between 0.001 to 0.878 pg / m3.

The results show TRXRF technique is a powerfull analytical tool, that allows to obtain both, accurate and reproducible data for a wide spectra of elements, j

45

U ■ : gt^OO bty

ANALISIS CUANTITATIVO DE SEDIMENTOS USANDO EDXRF

A. Cameiro*, V. Nascimento*** Departamento de Fisica, UNIMEP,Sao Paulo, Brasil.••Departamento de Fisica e Meteorolo- gia, ESALQ/USP, Sao Paulo, Brasil.

Lah energy dispersive X-ray fluorescence analysis with radioisotopic excitation is proposed for analysis of sediment, biological and environmental samples, presenting high light fractions (elements with atomic number less than 13). The procedure is based on the fundamental parameters method for element concentrations evaluation with Z > 13, and in the coherent and incoherent scattered radiation for the evaluation of the light fraction.

In the fundamental parameters method, standard pellets produced from pure chemical compounds was used, to estimate the relationship between the fluorescent intensity and the element concentration, through elemental sensiti­vity and geometry factors for fluorescence. These same standards were also used to determine the relationship between light fraction content and coherent and incoherent geometric factors.

To excite the elements in the Mn to Zr range a 109Cd - 0.37 GBq annular radioactive source was used, and HFe - 3.7 GBq for A1 to Cr. For the X-ray detection a Si(Li) detector coupled to an multichannel emulation card was employed. The characteristic net X-ray intensities, and coherent and incoheren­tly intensities were obtained using the AXIL software.

To test the proposed procedure, two certified samples (Soil-5/IAEA and SARM-4/SABS) were analysed. These samples were diluted with boric acid in 1:4 proportion and pelleted with superficial density of aproximately 100 mg.cm2.

Initially the light fraction was evaluated from the primary coherent and incoherent scattered Ka Ag X-rays intensities, resulting 29.5% 0 and 70.5% Ne to the Soil-5, and 78.7% 0 and 21.3% Ne for SARM-4.

For the S5Fe excitation, the primary coherent and incoherent scattered Ka Mn X-rays intensities were used, resulting 71.5% N and 28.5% O to the Soil-5, and 10.14% O and 89.86% N for SARM-4. To obtain speed in the analysis a software in Basic language for IBM compatible microcomputer was developed.

It was possibly to carry out with this proposed method simultaneous and quantitative analysis of Al, Si, K, Ca, Ti, V, Mn, Fe, Zn, Rb, Sr and Zr. The errors in the concentration related to the certified values were aproximately 20%, except for Fe, wich was near 1%.

This method gives advantages over empiric and semi-empiric methods, because requires a small number of standard samples, prepared from pure chemical compounds, and permits quantitative analysis of some elements, whose standards sometimes not available in the laboratory. ~j

46

CLWOOOW

ESPECTROMETRIA DE ENERGIA DISPERSIVA PARA ANA- LISIS CRISTALOGRAFICO Y QUIMICO DE MUESTRAS MINERALES

E. Greaves*, L. Sajo-Bohus*, J. Sosa** •Departamento de Fisica, Universidad Sim6n Bolivar, Caracas, Venezuela. **Instituto de Geologia y Paleontologia, La Habana, Cuba

L The principles and practice of X-ray diffraction and fluorescence by energy dispersive spectrometry in total reflection geometry are described. The diffractometer is based on a modular system. The X-ray tube supplies either a camera for energy dispersive diffraction (EDXRD) or a unit for total reflection' fluorescence (TXRF)- The diffraction and fluorescence signals are collected with a high resolution'^i(Ll)'solid stateHetgctOT) the signal manipulation is done with nuclear electronics thaFIncludes a PC-based multichannel analyzer. The PC combines the functions of signal acquisitionand data processing. Among the main features the system incorporates the means for calibration of this dual uni t spectrometer-difractometer. Acquisition and storage of diffractograms as well as iterative chi-square fitting of signal intensities is done by means of the QXAS package. Calculation of interplanar spacings of samples is accomplished with a routine using the fitted energy spectra. Sample chemical element identification is obtained with QXAS. Computerized search of the crystalline phase is carried out with the JCPDS file which is in a CD-Rom connected to the same system. We present results as examples of sample analyses. The potential and limitations of the technique are discussed as well as recent results from the literature (1,2).

1. N. Ojeda, E. Greaves, J. Alvarado y L. Sajo-Bohus. Dertermination of V, Fe, Ni and S in petroleum crude oil by reflection X-ray fluorescence. Spectrochimica Acta 48B, 247-252 (1993), (4th Workshop of TXRF, Gees- tachth, Germany, May 1992).

2. K. Hayashi, K. Ishida, T. Horiuchi y K. Matsushihge. In situ X-ray observation of in plane cohesive structure in evaporated thin film. Dep. of Applied Science, Fac. of Engineering, Kyushu University, Fukuoka 812, Japan (Preprint 1992) (4th Workshop if TXRF, Geestachth, Germany, May 1992).

Work partially financed by IAEA, Vienna, Austria throug project VEN/ 2/006 and project PC-79 of CONICYT, Caracas, Venezuela, "j

■ aiwonUSD DE ED-XRF EN EL DIAGNOSTIC© DE PROBLEMAS AMBIENTALES

R. Odino, B. SoutoDireccidn National de Tecnologia Nu­clear, Montevideo, Uruguay.

£ This work was originated due the necesity to determinate the amount of

47

K and Ca in sedimentable dust samples taken from the surrandings of a Portland Cement Factory, which constitued a significant focus of air containation of the area. The samples were obtained following PAN AIRE (Panamerican Net of Normalized Sampling of Air) from OPS since 1988 until 1993.

By the way, the contamination in soils and muds generated by a Sodium Hidroxide-Chloride Factory was analyzed, in this case, the assey of Hg was solicitated, which is used as an electrode in the production of chloride. The samples have been obtained since 1992.

As the ED-XRF is a multielemental technique with application to major, minor and higher trace elements, in both cases the presence of other contami­nant elements not considered before was evidenced in the Factory's areas.

The Enrichment Factors are calculated for several elements of the sam­pling stations using Fe as the reference element. As there are no date of the chemical elements mean abundance in the soils of Uruguay the values given by the Mason's Table for the Earth Crust (EFc).

Due to possible differences that may arise from the use of the table named above, those elements with EFc>3 are considered as «enriched».

After studying the results of the the factories had to change the way of contaminants disposal to the observed assays in Ca for the Cement Factory, which installed centrifuge filters: and Hg in the case of the Sodium Hidroxide - Chloride Factory which install filters in the wastewater discharge.

The improvements were checked analysing the new samples by ED-XRF, where again it is demostrated the great utility of e few multielemental technique. The technique was validated by certified standards.

These process were studied by the following elements: K, Ca, Ti, Mn, Fe, Cu, Zn, Ni, Cr, As, Pb, Hg, Br y Sr. J

g G^lOOOtQl/USO DE EDXRF CON EXCITACION RADIOISOTOPICA EN

EL ESTUDIO DE LA DINAMICA DE LA VINAZA EN ELSUELO V' r

S. Simabuco*, V. Nascimento*** Depart amento de Hidraulica e Sanea- mento.FEC/UNICAMP, Sao Paulo, Bra­sil.**Departamento de Fisica e Meteorolo- gia. ESALQ/USP, Sao Paulo, Brasil.

I_ X-ray fluorescence is a multielemental and simultaneous analytical tech­nique based on the measurement of the characteristics X-rays emitted by the chemical elements present in the sample.

For the element excitation two annular radioactive sources (55Fe -3.7 GBq and 109Cd - 0.37 GBq) were employed and for analysis samples in the pellet shape

48

were used, with superficial density of aproximately 100 mg.cm1, diluted with boric acid in 1:4 proportion. For the characteristic X-rays detection an high- resolution system were used, based in Si(Li) semiconductor detector coupled to a multichannel emulation card inserted in a microcomputer.

This technique requires calibration methods to convert characteristic X- ray intensities to elemental concentrations, based in empirical curves or mathe­matical relationships derived from physical properties of the elements and physical characteristics of the detector system, and taking into account the matrix effect correction.

The precision of the analysis depend on the methods applied for the X-ray spectra evaluation and calibration of the system. In this work the X-ray spectra fitting was done using the AXIL software and the calibration of the system (determination of elemental sensitivities, efficiency of the detector system and geometry factor) was carried out using the fundamental parameters method, employing chemical compound standard samples.

When the 109Cd source was used for excitation of the elements on the ran ge from “Ti to "Mo, the absorption of the characteristic X-ray was corrected using the transmission or irradiator technique. For the elements in the range 13A1 to UV excited with “Fe, it was necessary to use another procedure, based in the absorption edges, as the sample is not transparent for the incident and emergent X-rays in this range. To obtain analytical speed a software in Basic language was developed for IBM compatible microcomputer.

To evaluate the proposed method, three certified samples (Soil-5/ IAEA, SL-l/IAEA and SARM-4/SABS) were analysed and the results compa­red. The errors were about 10 - 20% for majority of the elements, and less than 10% for Fe and Zn in the Soil-5, Mn in SL-1 and Ti, Fe and Zn in SARM-4 samples.

The technique was then employed for the instrumental and simultaneous concentration determination of several elements present in sandy and cleyey soils treated with vinasse (4000 m,ha1), in experiments conducted in laboratory conditions. In all column profiles treated or not with vinasse were possible to verify the distribution of Al, Si, S, Cl, K, Ca, Ti, V, Mn, Fe, Cu, Zn, Br, Rb, Sr, Y, Zr and Nb.

A significative concentration increase of S, CL K and Ca was observed in the two soil profiles up to 30 cm depth, and the same could be infered to Cu, Zn, Rb and Sr contents. With reference to other elements, there was no difference compared to the control, due to their high content in natural soils accomplished by a low content in the vinasse.

/APLICACIONES DE PIXE AL ESTUDIO DE BIOACUMULA- CION DE METALES, EN PESCADOS DE RAPEL

M. Dinator, I. Villa, P. AuriolFacultad de Ciencias, Universidad de Chile, Santiago, Chile.

The Rapel freshwater reservoir located in central Chile (34.1* S, 71.4* W)

49

presents a case of potential pollution due to tailings from copper processing plants discharged to Alhud River.

PIXE analysis of different tissues from Odontesthes bonarienses. the most abundant species in the lake, have been performed as a part of a project developed to evaluate the impact of metal pollution to this ecosystem.

Samples of muscle, liver and gills were irradiated with 2.2 MeV proton beams provided by the cyclotron of the University of Chile. Ten elements were detected: P, S, Cl, K, Ca, Fe, Co, Ni, Cu, and Zn. Five of these elements were common to all samples, while Cl, Co, Ni, Cu and Zn appeared in some of them.

In Table I, We present the enrichment factors of each element in liver and gills relative to the corresponding ones in muscles, using potassium as a reference.

In order to have an estimation of the pollution levels in fishes from Rapel reservoir we calculated enrichment factors with respect to same tissues from fishes from Adriatic Sea. Results are given on Table II.

Table I shows that enrichment factors for all the detected heavy metals are higher in gills, except for iron which is higher in liver as expected.

From Table II, we see that in liver the elemental contents are rather similar in both species, except for Ca, Cl and Ni. In gills the differences are more dramatic specially in Ca, Ni and Cu, showing a preference of this tissue to absorb these elements. Cu was detected in only one individual. Muscles are much more enriched in all elements.

TABLE I

P S Cl Ca Fe Co Ni Cu Zn

Liver/Muscle 0.77 1.5 2.3 0.30 3.7 1.3 0.40 1.5 1.9Gills/Muscle 2.1 0.86 0.92 3.1 1.4 2.6 2.9 2.4 2.2

TABLE II

S Cl Ca Fe Ni Cu Zn

Liver 1.5 0.13 5.5 0.86 0.5 0.7 0.9Gills 1.4 0.26 40.0 1.9 34.0 50.0 1.5Muscle 1.8 1.5 53.0 12.0 303.0 38.0 8.8

Work supported in part by FONDECYT Grant 1074-91

50

m oL^i^toD^DETERMINACION DELGRADO DE CONTAMINACION FOR MET ALES PESADOS A LO LARGO DEL LITORAL CHILENO, UTILIZANDO PERUMYTILLUS PURPURATUS COMO BIO MONITOR Y TECNICAS NUCLEARES Y NO NUCLEARES COMO METODOLOGIAS ANALITICAS

L. Muftoz*, N. Gras*, S. Hurtado*, H. Pinochet**, I. de Gregory**, D. Delga­do*** Comisldn Chilena de Energia Nuclear, Santiago, Chile.**Universidad Catdlica de Valparaiso, Valparaiso, Chile.

1_ Chile has a favourable position to develop fishing activities since it has approximately 4.500 km of coastline bordering the South Pacific Ocean, the seawater is rich in nutrients and contains a great variety of marine organisms, are susceptible to be polluted by trace elements produced specially by the mining industrial processing of ore and metals.

In this paper we present the results obtained for Cadmium, Copper and Zinc contents in water, sediment and mollusk samples collected from different geographical areas located along the Chilean coast

The main reason to use of the mollusk Perumytillus Purpuralus (chorito maico) like a biomontor is determined for the ocurrence of this biological spices through all the Chilean coast. The mollusk samples were analyzed by instru­mental and radiochemical neutron activation analysis. The seawater and sediments were analyzed using differential pulse anodic stripping voltametry and atomic absorption spectroscopy. *"l

ANALISIS DE ELEMENTOS MAYORESYTRAZAS EN PLAS­MA SANGUINED FOR FIXE

F. Llona, R. Morales Departamento de Fisica, Fac. de Cs., Universidad de Chile, Santiago, Chile.

L Besides the eleven major elements that are essential to humans organisms there are some nutrients elements at trace levels like Mn, Fe, Cu, Zn, etc. That are forming part of enzimatric and proteinic systems. Some clinic disorders and pathologies of high importance in Chile like chronic diarrhea, some kind of anemias, growing alterations and anticipated birhts are associated with the presence of this micronutrients.

Chile with high mining activity has in certain areas environmental problems with the presence of toxic elements like Mn, As, Pb, Cd, etc. Also in

51

Santiago the Capital with a confined geographic situation where the 40% of the population lives have a high airborne particulate exposure and lead pollution coming from industrial operations ana vehicular traffic.

In this work it's developed the optimisation of the PIXE Technique using the isochronous cyclotron of the University of Chile for the analyses of major and trace elements with emission lines between the 2 keV and 12 keV of energy.

The advantages in the use of PIXE technique are two: there is no sample treatment except the addition of Ittrium as internal standard, the other advan­tage is the posibility of thin target preparation, where the matrix effects are lower.

As an application of this method were analyzed samples of plasma b lood of sixteen pregnant women in there last weeks. Were determinated five major elements: P, S, Cl, K, Ca and four trace elements: Mn, Fe, Cu and Zn.

/■ zCWOOOA

NIVELES DE MERCURIC TOTAL EN MUJERES EMB ARAZA- DAS Y NODRIZAS RESIDENTES EN PUEBLOS DE PESCA­DORES EN LA OCTAVA REGION DE CHILE

C. Bruhn*, A. Rodriguez*, C. Barrios*, V. Jaramillo*, U. Gonzilez**, J. Bece­rra**, N. Gras***, O. Reyes****, SEREMI-Salud****.* Facultad de Farmacia, Universidad de Concepcion, Concepcion, Chile.** Universidad de Chile, Santiago, Chile. ***Comisi6n Chilena de Energia Nuclear, Santiago, Chile.****SEREMI-Salud, Octava Region.

[_ Mercury pollution resulting in particular from industrial activity (e.g., chloroalkali plants), is well know since 1977 in the coastal zone of the Eighth Region of Chile comprising the Bays of Concepcion and San Vicente and the Arauco Gulf. Relatively high mercury levels were found in waters, sediments, and seafood samples in previous research studies conducted by the University of Concepcion under contract with the Regional Ministery for Planning. The aim of the present work is the assessment of the environmental exposure to mercury mainly through the diet (e.g., consumption of fish and fish products) by high risk human groups in this area. Human scalp hair was selected as indicator for exposure and total mercury (Hg-T) was determined in hair by cold vapor atomic absorption spectrometry (CVAAS) after sample dissolution by acid wet digestion in sealed Pyrex ampoules. The population under study is composed by pregnant and nursing women residents of 10 fishing villages (FVs) in the Eighth Region (Dichato, Coliumo, Cocholgue, Lenga, Tumbes, Chome, Laraquete, Tubul, Punta Lavapie and Quidico), mainly with at least one fish meal eaten per week, and the control group was an equivalent population with negligible or no fish cnsumption and resident in Pinto, a small town located inland far from the coast. Both populations were surveyed by the application of a questionnaire including nutritional history, habits and morbidity during the last two weeks.

52

Preliminar work dealt with the characterization and validation of the methodology in use, through the assessment of linear working range, characte­ristic mass reproducibility, precision, accuracy and detection limit. Instrumen­tal neutron activation analysis (INAA) was used as reference method for external quality control of hair Hg determinations. The absolute detection limit by CVAAS was estimated as 0.13 ± 0.01 ng Hg-T (3 x oBl). Accuracy and precision were assessed with the aid of various biological and environmental certified and standard reference materials including human hair, and were satisfactory for ppm and sub-ppm Hg-T. There was a significant correlation between hair mercury content obtained by CVAAS and INAA for 21 women studied (r2 = 0.81, pS 0.0001 at 95% conf. level) and no significant differences were stablished by paired t-test (mean = 0.09,, std error = 0.19,, t calc. = 0.475, p = 0.640).

The Hg-T content in hair of the study group was significantly higher than that of the control group. In the former (n = 59), the arithmetic mean ±s.d., the median and the geometric mean were 2.06 ± 1.45, mg/ Kg (range 0.16-7.12mg/ Kg), 1.70 mg/Kg and 1.66 mg/Kg, respectively, whereas in the control group (n=7)the corresponding results were 0.43 ± 0.18, mg/Kg (range 0.20-0.79) mg/ Kg), 0.40 mg/Kg and 0.40 mg/Kg, respectively. Upon application of t-test, the mean of the study group was significantly higher than the mean of the control group (t calc. = -7.680 for unequal variances), p = 0.0001. These results are presented and discussed to charactize the study group according to geographi­cal location, fish and seafood consumption, age and residence period in the fishing village. J

Article to be publised in J. Trace Elem. Electrolytes Health Dis.

This study was supported by IAEA under research contract N“ 6331 / RB and by the Direccidn de Investigacidn, Universidad de Concepcion, Concepcion (Project 4.91.71.001)

CONCENTRACION DE As EN CABELLO MEDIANTE ANA­LYSIS FOR ACTIVACION NEUTRONICA, UN MONITOR AMBIENTAL

A. Jamett*, L. Pena*, M. Santander*N. Gras**, L. Munoz**•Universidad de Antofagasta, Antofa­gasta, Chile.**Comisi6n Chilena de Energia Nuclear, Santiago, Chile.

J This work presents an environmental application of Neutron Activation Analysis determining As concentration in human hair samples.

Samples were collected from several localities in the North of Chile, Second Region. For many years this zone has presented high arsenical contents in its grounds, as in its waters supplies.

The increasing mineral activities and the water supplies without and adequate treatment contribute to the presence of Arsenic in the environment.

53

Regional inhabitants are exposed at different degrees to this element or its compounds.

The arsemic level in hair samples is considered as good indicator of the total presence of As at non occupational ambients. There are a large amount of factors influencing the arsenical concentration in hair samples, so to obtain a great homogeneity we worked with groups of individuals of same age, like children of six years old, with a minimum permanence of four year in their localities.

We obtain samples in Chuquicamata, Calama, Sam Pedro de Atacama, Maria Elena and Antofagasta. At Chuquicamata and San Pedro de Atacama, we have information obtained with four years of difference. The concentrations of samples from Antofagasta were considered as reference, due the characteristics of this city.

The results present a high level of Arsenic at Chuquicamata. Neverthe­less, the concentration obtained four years later is aproximately 50% lower that the level obtained in 1987. J

m Of)WcD%COLECCION DE MUESTRAS BIOLOGICAS Y AGUA EN ZONAS AISLADAS, PARA ANALISIS DE TRAZAS Y ULTRA- TRAZAS MEDIANTS AAN

N. Gras*, R. Downing***Comisi6n Chilena de Energia Nuclear, Santiago, Chile.•‘National Institute of Standards and Technology, Maryland, USA.

//increasingly, the desire to improve industrial development and the quality of life has resulted in undesired changes in the environment. Sometimes the changes are immediate, causing loss of plant and animal life or the loss of jobs, homes, and health. More often the consequences are quite subtle, taking years to reveal themselves. To correctly identify pollution and its effects requires that the techniques used to collect samples and for the analysis are appropliately chosen for the concentration levels of interest. Equally important, the samples must be meaningful for the questions being ask about the environ­ment. Furthermore, the samples must be of high integrity, that is, representative of the material being sampled. This process is particularly difficult as environ­mental samples are commonly taken from such diverse sources as air, water, soil and a variety of biomonitors.

In this work we have concentrated on obtaining representative samples of the highest integrity even though the environmental conditions for collecting the samples were severe and the sampling locations were quite remote from clean room conditions. Clever adaptations in the sampling methods were devised to overcome difficulties encountered in the field with wind and dust, cold and heat, and the lack of laboratory conveniences such as filtered air or electrical appliances.

54

Samples were collected specifically for elemental determinations using

Etron activation analysis (NAA) techniques,

ANALISIS CUANTITATIVO DEL CONTENIDO DE RADIO- NUCLEIDOS GAMMA EMISORES EN ALGUNOS DE LOS PRODUCTOS ALIMENTICIOS DE LA DIETA BASICA DEL VENEZOLANO

L. Sajo-Bohus*, E. Greaves*, P. Deho- llain*, H. Ferrer H.*, M. Guerra*, J. Broadway**, H. Ferrer R.***•Universfdad Sim6n Bolivar, Caracas, Venezuela"National Air and Radiation Environ­mental Laboratory, USEPA, Montgo­mery, USA.•"Universidad del Zulia, Maracaibo, Venezuela.

Lin this study we present the gamma emitter radionuclide concentration present in a set of few recurrent product in the basic diet of the Venezuelan population. The analytical technique consists in measuring the gamma energy in a pulse high spectrum from which a selected radioisotope concentration can be determined.

A statistical method is applied to the characteristic parameter that chan­ges with time during low level counting in the presence of low background, observing that the system has a good operational stability. With the aim to optimize the quality of the results, samples were measured in four different laboratories.

The counting efficiency was measured for different geometry, food stuff and gamma radiation energies, showing that for this spectrometer system a LLD value less than 0,5 (Bq/1) (Efa» 0.661 Mev) us attainable. The software for radioisotopes identification and concentration determination is SPECTRAN- AT (Canberra Ind, USA) and it was tested by comparison with data calculated manually.

Few comments on the risk derived by consuming food products with low content of radioactive Cesium-136 conclude this work J

Work supported by the IAEA, Project VEN/9/005

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EVALUACION DE EFECTOS SUBLETALESINDUCIDOS FOR LA CONTAMINACION ORGANICA, SOBRE LA MACRO­FAUNA BENTONICA DE BAHIA CONCEPCION, A TRAVES DE RADIOISOTOPOS NATURALES

L. Farias, M. SalamancaDepartamento de Oceanografia, Univer- sidad de Concepcidn, Concepcidn, Chi­le.

L-The sediment distribution of “Th (half life 24.1 days) and 210Pb (half life 22.3 years) reflect the benthic macrofauna bioturbation activity. Therefore, any natural and antropogenic process that affect the burrowing activity of benthic organisms will affect the distribution of these nuclides in sediments. Thus, the in situ sublethal effects of pollution processes on burrowing activity of macro- benthic infauna of Concepcion Bay sediments was studied using radiochemical parameters (DB and inventory).

Both sediment radiochemical and benthic samples were collected in four locations along a transect from Talcahuano Port to the central of Concepcidn Bay in January and August, 1991.

The vertical distribution of 2MTh, 22*U, 110Pb and derived radiochemical parameters (inventary of “‘Thxs and 210Pbxs, accumulation rate and biopertur­bation coefficient) together with X-radiograph of sediments column were ana- lized and compared.

The numerical abundance, biomass and species diversity were measured and a numerical clasification analysis of benthic infauna was made to anaiize variations in community characteristics to evaluate them as function of radio­geochemical parameters.

The X-radiographs shows, in Station 1 close to Talcahuano Port, and in both sampling periods the inexcistence of biogenic structures in the sediment column and laminations.

This stations shows a higher homogeneity, as result of continuous resus­pension and deposition. In the other station far from the point of maximum discharge of sewage sludge, perturbation caused organisms activities, e.g. the polichaet Paraprionospio Pinnata, between the water-sediment interface and 6- 9 cm into sediment was observed.

The calculated sediment mixing coefficients (DB) show high correlation with biomass, abundance and diversity. On the other hand, the DB's values normalized to biomass showed that there is an increase in biological activity in direction to bay entrance. This means that the organisms closet to the point of organic discharge present less biological activity.

Due to high correlation found between the DB's values and the invento­ries from %*Thxs and 210Pbxs with community parameters, it can be suggested that these radiochemical indices are apropiate in situ indicators of pollution processes acting on the macrobentic comunity of organisms. 1

56

PUENTES DE 110Pb EN LA BAHIA DE CONCEPCION

M. Salamanca.Universidad de Concepcidn,Concepcidn, Chile.

i-The sources and sinks of 210Pb to Concepcidn Bay waters were evaluated

to discern the relative importance of the main removal and supply mechanims of this radionuclide to the waters of Concepcidn Bay.

The main inputs of ,10Pb are the atmospheric supply and the ad vection of offshore upwelling waters. The atmospheric inputs was measured in precipita­tions using a collector and in Rocuant and Raqui marsch sediments. Both estimates agree very well and the average supply of 2,0Pb for Concepcion area in about 0.3 dpm cm 2 yr*. The advective input from upwelling varies between0.6±1.3 to 2.1±2.0 dpm cm2 yr1. ,10Pb is removed efficiently from the water column as shelf water with 2WPb content crosses the continental shelf off Concepcion Bay, with 210Pb/226Ra that decreases by a factor of 3 to 4 before reaching the interior of the bay. This is coincident with an increase of suspended matter concentration towards inside the bay. The 210Pb supplied by the Andalien River and in situ production from “‘Ra are neglible.

The main removal of 2l0Pb from Concepcion Bay waters is deposition in sediments. There is an increase of the excess 2l0Pb inventories toward the bay entrance (by a factor of 2) and outside the bay sediments (by a factor of 7). This pattern can be explained by an increase of mixing of sediments by the benthic infauna and enhanced removal of 2l0Pb from the water column by particles near the mouth. Mass balance calculations indicate that within the uncertainnities of the calculations the inputs (0.9±1.2 to 2412.0 dpm cm 2 yr1) and outputs (0.512 dpm cm2' yr1) of 210Pb are in balance in Concepcion Bay. The residence time of 2,iPb vary between 43 to 17 days.

The results of this research indicate that 2l0Pb and maybe other particle- reactive contaminants (such as heavy metals) are retained and redistributed inside the bay by circulation, resuspension and biological mixing. *J

m c i^ooojoAPLICACIONDETECNOLOGIAS NUCLEARES ENDESCON- TAMINACION DE LIQUIDOS

R. Labayru, E. Andalaft, C. Albornoz and M. CorreaComisidn Chilena de Energia Nuclear, Santiago, Chile.

F_ The discharge of contaminated industrial liquid wastes is regulated by increasingly tighter legal and environmental standards.

57

The potential applications of the novel separation processes, such as micro and ultrafiltration, osmosis, electrodialysis and ion exchange, for treating industrial wastes from different aqueous streams is under consideration.

The production of inorganic membranes has been studied in order to obtain one suitable to work in radioactive media, to be able to separate and concentrate cations presents in nuclear wastes streams. The present report describes work in which electrodialysis has been carried out using a barium phosphosilicate membrane (BPS).

The average pore size of the membrane was found to be 15.2 nm (BJH average pore diameter) with a surface area equal to 7.5 square meter per gram. The average pore size of the support used was about 2.5pm for both filter paper Whatman 50 and ceramic.

The effect of gamma irradiation on membranes has been studied. The superficial area changed from 7.5 to 8.4 sq.mt./gram of membrane, and the total porosity increased post irradiation test at 7.5 Mrads in a Co-60 source.

It was noted an improvement of the inorganic membranes after irradia­tion test. This is necesary to obtain membranes for NF, UF and MF with an average pore diameter ranging from few Amstrongs to hundred micrometers.

The development of the new inorganic materials has turned interest in membrane processes, and particulary, the results obtained show that membrane processes is a potentially useful method for treating nuclear, aqueous wastes and decontaminate different industrial effluents. These processes may be opti­mized by using radioactive tracers. ~]

EL USO DEISOTOPOS ESTABLES EN GEOLOGIA DEL ME­DIO AMBIENTE Y EL CONTROL EN POLUCION MINERA

C. RoeschmannServicio Nacional de Geologia yMinerfa, SERNAG EOMIN,Santiago, Chile.

i_ Chile has major world reservs of copper and lithium, natural nitrates and other mineral resources, this is why the mining activity is the principal incoming of money from abroad.

The mining activity has some centuries and was hardly increased in the last century without adecuated environmental control. This has deteriorated the natural environment, situation in some cases of dangerous levels. The increased activity that mining will have in the next decades makes necessary to take environmental controls.

For the environmental control in general and for the mining activity in particular the knowledge of the Geology of the Country and the Physical- Chemical procedures that model the continental crust and the marine platform are essential for the definition of the call antrophogenic pollution.

58

The National Geologycal and Mining Service of thile is called to give up an interpretation, difinition and control of the different kinds of pollutions at the present and the impact for the future and specially the one that is coming from the mining activity.

For this task the National Geological Chart and the Metallogenic, Hydro- geological, Geochemical maps are the base for the discrimination between the natural phenomenous and pollution.

In order to carry on this tasks the National Geological and Mining Service must use the most modem techniques, and as a very important tool the use of stable isotopes that are essential in the interpretation of geologic processes and sources of information for the description of the environmental degradation.

The study of isotopes of H, O, C, S, N and isotopes of the nobel gasses He, Ar, Kr, Xe and Rd along with the heavy isotopes of radiogenic origin like Sr, Nd,

Pb, can define the relations between the Atmospher, Hydrospher, Bios- pher, Litospher and Superior Crust in relation with the man increased activity that alterates the natural environment.

The development of the Isotopic and Environmental Geology requires an interdisciplinary contribution. The high cost of the instrumentation and the insufficient economical resources of the Goberment institutions makes neces­sary there coordination in specific tasks.

The present work propose the means of diferent application of the Isotopes in Environmental Geology and the projects that the Geological Service must develop in agreement with the Comisidn Chilena de Energia Nuclear in relation to nuclear techniques. 1

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BRASIL PAULO E. ARTAXO NETTO*UNIVERSIDADE DE SAO PAULO Instituto de FfslcaCalxa Postal 20516 CEP 01498-970,SAO PAULO EMAIL: (INTERNET) ARTAXO® USPIF.IF.USP.BR FONO: 55-11-81 55 599 r.7016Fesidencia 55-11-87 24 997 FAX : 55-11-81 40 503

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SECRETERIAOO DEL SEMINAR1Q

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ARGENTINA JORGE G. GRAINO Gerencia de Area de Radioisotopes y radiacio- nes (cp 1429)Avda. del Libertador 8250Buenos AiresFONO: 54-1-701 9856FAX: 54-1-70 0229 BRASIL

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BRASILBRASIL SELMA MATHEUS

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BRASIL OLIVIA KIMIKO KIKUCHI Travessa R.400 Cidade Universitaria.CEP: 05508-900 S3o PauloFONO: 55-11-260 2947 (Ext, 1593)FAX: 55-11-212 3546

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RUBENS MARTINS MOREIRA Centro de Desenvolvimiento da Tecnologia Nuclear COMISSAO NACIONAL DE ENERGIA NUCLEAR R. Prof. Mdrio Werneck s/n Campus U.F.M.G.Caixa Postal 1941 Belo Horizonte FONO: 55-031-441 5422 (R.132)FAX: 55-031-443 4744

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BRASIL DORA DE CASTRORUBIO POLI TravessaR.400Cidade Unlversitdrla-SP- SPCEP 05508-900Sdo PauloFONO: 55-11-211 6011 (Ext. 1583)FAX: 55-11-212 3546

CHILE

CHILE

OSCAR URBANODURAN FASTEN ' COMISION CHILENA DE ENERGIA NUCLEAR Amundtegui N8 95.Casilla 188-D Santiago FONO: 56-2-6990070FAX : 56-2-6991618

LAURA FARIAS UNIVERSIDAD DE

BRASIL MARIA HELENA DE OLIVEIRA SAMPA INSTITUTO DE PESOUI- SAS ENERGETICAS E NUCLEARES-IPENCaixa Postal 11049CEP 05499-970Sdo PauloFONO: 55-11-211 6011

CONCEPCIONDepto. de Oceanogralia. Casilla 2407-10 ConcepcidnFONO: 56-41-234985- 2502FAX : 56-41-240280

Ext. 1596FAX: 55-11-212 3546

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BRASIL MARIA CRISTINA ROSA YAMASAKI TravessaR.400 Cidade Universita- ria CEP 05508-900S5o PauloFONO: 55-11-211 6011Ext. 1592FAX: 55-11-212 3546

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2598 CHILE NELIDA EMILIA HERESI MILAD"HERESI Y ASOCIADOS

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CHILE

CHILE

CHILE

CHILE

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SantiagoFONO: 56-2-6990070 FAX: 56-2-6991618

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URUGUAY ROSARIO ODINO MOURE, DIRECCION NACIONAL DE TECNO­LOGIA NUCLEAR Encargada de Laborato­ryMercedes 1041, MontevideoFONO: 598-2-906919/ 612653FAX: 598-2-921619

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VENEZUELA LASZLO SAJO-BOHUS UNIVERSIDAD SIMON BOLIVARDepto. de FisicaApartado 89000, Caracas YV-1080ACaracasEMAIL: LSAJO@USB.VE FONO: 58-2-906 3659 / 937 429 01.FAX ; 58-2-963 3230 / 963 4102

* Panelistas invitados

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