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ANEXO 3: REPORT ON THE SOIL SAMPLING AND PRELIMINARY ANALYSIS

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Report on the soil sampling and analysis of the soil data

of the Determinación de línea base nacional de contenido de arsénico

en material particulado respirable Project

Contents:

ABSTRACT.......................................................................................................................................................... 2 RESUMEN ........................................................................................................................................................... 2

1. GENERAL REMARKS.................................................................................................................................. 3

2. DATA ACQUISITION ................................................................................................................................... 3

3. MATERIALS AND METHODS................................................................................................................... 4

SOIL SAMPLING .................................................................................................................................................. 4 PM10-SAMPLES ................................................................................................................................................. 5

4. SAMPLING STATIONS................................................................................................................................ 7

4.1 PICA ............................................................................................................................................................. 7 4.1.1 Pica sampling points .......................................................................................................................... 8

4.2 QUILLAGUA ...............................................................................................................................................10 4.2.1 Quillagua sampling points...............................................................................................................11

4.3 TOCONAO...................................................................................................................................................14 4.3.1 Toconao sampling points .................................................................................................................15

4.4 DIEGO DE ALMAGRO .................................................................................................................................18 4.4.1 Diego de Almagro sampling points .................................................................................................19

4.5 VALLENAR .................................................................................................................................................21 4.5.1 Vallenar sampling sites....................................................................................................................22

4.6 QUILLOTA ..................................................................................................................................................24 4.6.1. Quillota sampling points.................................................................................................................25

4.7 TALCA ........................................................................................................................................................27 4.7.1 Talca sampling points ......................................................................................................................28

5. INTERPRETATION OF THE SOIL DATA ............................................................................................ 29

6. GLOSSARY OF SOME GEOLOGICAL AND PEDOLOGICAL TERMS ....................................... 35

7. LITERATURE............................................................................................................................................... 36

APPENDICES .................................................................................................................................................... 38

APPENDIX I: CHEMICAL ANALYSES ................................................................................................................38 I.1. Soil samples .........................................................................................................................................38 I.2. PM10-samples .....................................................................................................................................39 I.3 Estimation of the uncertainty in analytical results of the soil samples.............................................39

APPENDIX II: SAMPLING SITE PICTURES ................................................¡ERROR! MARCADOR NO DEFINIDO.


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Abstract This advance report shows the results and a first analysis of Conama’s Determinación de línea base nacional de contenido de arsénico en material particulado respirable project’s soil sampling part. The concept of the soil sampling in this project is to understand the influence of breathable arsenic particles from the soil upon the breathable As particles suspended in the air. All the sampling sites in northern Chile show a high As content in the soils, some a very high one. One assumption was that a higher As content in the soil will lead to a higher As content in the surrounding atmosphere because the As content in the soil of a sampling station would have a direct impact upon the As suspended in the air at the same location. We also supposed that aeolian As deposition and distribution is higher close to the emitters and gradually decreases over distance. The aeolian As deposition was assumed to be even over the relatively small sampling site areas. The results from the air samplers show that the geogenic As content in the soil seems to have a very much smaller impact on the As content in the air than the industrially emitted As. The local distribution of As in the soils has no great influence and direct correlation on the As suspended in the air. Additionally the aeolian transport of the breathable As particles has no mayor impact on the soil contamination. The As content in the soil is mainly controlled by alluvial sedimentation processes.

Resumen Este informe de avance presenta los resultados de los primeros análisis de las muestras de suelo del proyecto de Conama Determinación de línea base nacional de contenido de arsénico en material particulado respirable. La idea de la parte de muestreo de suelos en este proyecto es entender la influencia de los particulos respirables del suelo hacia los particulos respirables suspendidos en el aire. Los sitios de muestreo en el Norte y el Norte Chico tienen un elevado contenido de As respirable en el suelo, algunos contenidos son muy altos. Una suposición era que un contenido elevado en el suelo efectará también el contenido de As en la atmósfera cercana en el mismo sitio de muestreo, considerando que el As eólico es depositado y distribuido de modo uniforme sobre los áreas de meustreo de suelo. Los resultados de los filtros de aire muestran que el impacto del As geogénico al As suspendido en el aire es probablemente mucho menor que el impacto industrial. La interpretación de los resultados lleva a la conclusión, que el As respirable del suelo no tiene un impacto muy grande y una correlación tan directa a el As suspendido en el aire. Ademas el transporte y la deposición del As eólico no tiene una influencia muy grande a la contaminación de los suelos. El As en el suleo es controlado por mayor parte de procesos sedimentarios aluviales.


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1. General remarks The soil sampling part of the Determinación de línea base nacional de contenido de arsénico en material particulado respirable project was completed between the 20th of November and the 12th of December 1999. The sampling comprised about 10 – 15 samples in 7 sampling stations from the First to the Sixth of the Chilean Regions. The basic geological data upon the selected sampling sites is rather poor. Most of the information is provided in 1:250 000 scaled geological maps. This scale gives a good overview upon the regional geology but is too poor for detailed studies. In addition, the Chilean geological maps focus mainly upon mining aspects and not environmental issues. Therefore the quaternary geology, which in this case is the most interesting, is not mapped in great detail. Several questions concerning the quaternary geology appeared during the fieldwork. These questions comprised matters of special concerns towards a latter interpretation of the local distribution of the natural arsenic. These questions lead to the decision to perform the field work within two weeks in order to spend the last week in the Servicio Nacional de Mineria y Geologia (Sernageomin) [National Service for Mining and Geology] and to try to find answers to the unsolved questions. The discussions in the Sernageomin and the obtained data were very helpful and cleared several doubts. They form a useful basis for the analysis and interpretation of the sampling results.

2. Data acquisition The project team tried to obtain as much of the available geological data as possible before the start of the project. Unfortunately much of the information is unavailable or very old and two sampling sites (Pica and Talca) totally dispose of official geological maps in the 1:250 000 scale. A detailed research within the Sernageomin provided important unpublished data and in addition to this, there was good cooperation with regional experts and the Chilean-German project “Proyecto Ambiental Geológico-Minero, Cooperación Técnica Chileno-Alemana”. The Chilean-German project contributed information on the regional geology and the arsenic content in the top and subsoils of their study area (Rio Loa), see Fritsch et al., 1999. The Chilean-German project has also offered the Conama project soil samples from nearly 200 sites (top and subsoil). It is not clear yet whether these will be used and analysed by the Conama project because of the tight financial situation. The samples are stored in the laboratory of Sernageomin and are at Conama’s disposal for a latter analysis.


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3. Materials and Methods The topsoil sampling design comprised two transects that crossed each air sampling station, including one soil sample next to each air sampler. This design was adapted to feasible conditions in the field, i.e. several roads and paths that the team expected to use were in inaccessible. One transect of every sampling site had a length of approx. 5 km and contained 6-7 sampling points and followed the main atmospheric wind direction in Chile, North-South. A second transect, approx. 5 km long, (6-7 samples) crossed the first one, in the main local wind direction, generally East-West. The local topographical and infrastructural conditions made it sometimes impossible to follow straight lines within the transects; some transects follow more an ideal direction. Additionally the team took some samples of different parent rock material or from smaller creek-sediments aside of the major river system of a sampling point (“off-road samples”). The off-road samples play an important role in the final interpretation because they belong either to a different geological unit or to a creek that has sedimented a different kind of material than the one which is predominating in the area. The project financial frame did not allow a very detailed soil survey. Therefore the additional information of the “off-road” samples helps to explain doubtful variations in the As content of a certain area. For example, if the As content in samples of the same geological unit of an area is very high but the one of the “off-road” sample is not, then we can expect that the As in the soil is mainly of geogenic and not of anthropogenic origin. In Pica and Talca it was not possible to find an appropriate area for “off-road” samples. The total amount of samples per sampling station comprised 12 - 14 topsoil and 1 subsoil samples. The depth of the subsoil sample varied according to the development of the local soils. The sampling depth of the topsoil samples was 5 cm. This is the depth that generally shows the highest concentration of anthropogenic arsenic (see Fritsch et al., 1999). The climatic conditions contribute to the accumulation of the anthropogenic arsenic in the topsoil because the atmospherically deposited As is generally not washed into the deeper soil layers. The precipitation rates in the study area vary between 0-10 mm/a in the northern most points and up to 100 mm/a in Vallenar. Quillota presents 300 mm/a, Linares 700 mm/a. The potential evaporation exceeds the precipitation in all the air sampling sites except the one in Linares (see also Weischet, 1970). The sampling depth of 5 cm therefore yields the maximum amount of anthropogenic arsenic plus the natural arsenic contained in the soil.

Soil sampling

The soil samples were taken with a plastic shovel. The shovel was cleaned after each sampling point mechanically (wiping). The samples were sieved < 2 mm fraction at the sample site. The total amount of sieved sample was 1 l (1-2 kg). The sieved sample was packed in a 1 l plastic bag, which was placed inside a 2 l plastic bag. Both of the bags were labelled with the corresponding sample site code. The bags were closed tightly and the air was pressed out. The sieve was cleaned between every sample by tapping the sieve gently, brushing, and sieving a little amount of the next soil sample to the waste before sieving the real sample. All the sampling sites were recorded with a Global positioning


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system (GPS). The lack of detailed topographical maps made it impossible to check the exactness of the GPS coordinates in the field. To avoid misinterpretations caused by wrong GPS data, the team always made a detailed description of the sampling points and marked them on a road map. Generally the GPS results are very good but there are a few mistakes. The mistakes are explained in the text. A list of samples was enclosed to the samples before they were transported to the Chemical Laboratory of Sernageomin in Santiago for further handling. In the chemical laboratory of Sernageomin, the samples were dried in a temperature <40 oC. The dried sample was split and half of the sample was sieved to the <0.063 mm (<63 µm) fraction. The sieves were cleaned between each sample. An unsieved half of the sample was put back in an original plastic bag and stored. A maximum amount of 20-30 g of the sieved sample was weighed to the 0.5 l plastic bag and a sticker with a corresponding sample site code was attached to the bag. The bags were closed tightly and the air was pressed out to save space during transportation. The samples were sent to GTK's laboratory for analysis. The list with corresponding sample codes was enclosed. If more than 20-30 g fine fraction was gathered, the remaining part was put in a clean 0.5 l plastic bag, marked with a corresponding sticker and stored.

PM10-samples

The filters used for the collection of the PM10-particles were pre-weighed in the Chemical laboratory of the GTK before starting the monitoring. The accuracy was of one hundredth of a milligram (0.00001 g). Each filter was packed into its own plastic cover and marked with a stick-on label. The filters were transported to CONAMA and further to sampling stations. After the collection of the particles, the filters were put back to their covers and kept there until starting the analysis to avoid access of dust or other particles to filters, which might distort the results. Before starting the analysis, the filters were re-weighed in the chemical laboratory of the GTK. The total amount of particles collected in the filters could be calculated from the separation of the masses of filters after and before the sampling. An overview of the first sampling results shows that there is no obviuos and clear dependency in the relation between the breathable As in the soils an the the As collected in air samplers (see Table 1, Figures 1 and 2).


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Table 1: Overview on the As content in the soil samples

As mg/kg PICA QUILLAQUA TOCONAO DIEGO DE

ALMAGRO VALLENAR QUILLOTA TALCA

Number of samples

14 13 14 15 14 13 13

Minimum 29.7 144 38.5 26.4 12.6 7.2 8.6

Maximum 83.7 450 153 95.3 49.1 25.4 19.0

Median 43.1 276 61.4 42.4 24.9 17.5 12.6

Average 50.2 288 67.0 47.7 25.1 16.8 13.0


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4. Sampling Stations

4.1 Pica


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Pica is lying on a slope that dipps from the mountain range Altos de Pica towards the west, the valley Alto Matilla. The Altos de Pica are gently folded Palaeozoic sediments overlain by tertiary and younger Liparites (volcanic sediments, Rhyolites) and tuff. The overburden in the area is exclusively of quaternary origin, mainly alluvial. In the North and west dominate sand and sand dunes. To the east and the South of Pica the overburden consists of alluvial fans as well as sediments from mountain rivers. The Quebrada de Quisma, passing South of Pica in a deep valley, intersects most of the mentioned sediments (see also Bruggen 1916). If not mentioned otherwise, there is no in situ organic content in any of the Pica sampling sites.

4.1.1 Pica sampling points Pica-S (subsoil) and Pica-1: Altitude: 1300 m.a.s.l. The soil texture is purely sandy and finer (no stones at all); at least up to a depth of over 1m where we took the subsoil sample. The local guide said that the sand layer is very thick here and that the groundwater table is around 40m below the surface in the whole area. The sampling site is on a gentle slope just outside the city. The GPS recording was totally wrong; therefore the spot was artificially moved on the map to a representative location. Artificial contamination is possible in the whole area from eventual traffic (see tyre tracks in the pictures). According to local people, it is a recreation and local sport in the whole Atacama Desert to drive over the sandy plains with four wheel drive vehicles. This sport may cause local contamination. Another source of contamination is the aeolian transport of pesticides (“Homite”) used in the citrus fruit plantations in Pica (see Picture2). Pica-2: On the gentle slope north of Pica. The soil has a high Ca-content and is of sandy and finer texture (no stones). No organic content. The possible contaminations are the same as Pica 1 (Picture3). Pica-3: Sand dune. The texture is sandy and finer. There is no organic content. The sand dune is covered with dry leaves transported by wind from the citrus fruit plantations in Pica. This might also lead to a contamination with pesticides. (See Pictures 4 and 5). Pica-4: Same soil texture as in Pica-2 but with hardened carbonate horizons (costra; Picture 6). Silicate weathering processes free Ca and Mg, the lack of rain hinders Ca and Mg from moving into deeper soil horizons and they form endurated horizons. Pica-5: Sandy soil texture with very few stones. There is no organic content. The site is close to the local waste deposit, which can lead to human contamination. Pica-6: The sampling point lies on an old river terrace which is buried under young alluvial sediments. Close to the spot is a quarry for sand, gravel and boulders. The soil texture is sandy with a clast content of 20-30% in the topsoil.


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Pica-7: The sampling point is next to the riverbed of a temporarily flowing mountain river (quebrada). The texture is coarse sandy with 20-30% clast in the topsoil. The strong wind deflates the fine sand and leads to an accumulation of quartz grains in the surface (Pictures 7 and 8). Pica-8: The sampling point lies on an alluvial fan. The soil texture is sandy-clayey, the clast content 20-30%, lots of pebbles in the surface. Pica-9: South west of Pica, close to the valley of the quebrada de Quisma. The soil texture is coarse sandy, 10-20% of clasts in the topsoil. Pica-10: The sampling point lies on the slope of the Quebrada de Quisma valley (see picture 9 and 10. The soil is Sandy with low organic content. The valley is under agricultural use and the slopes are used as feeding places for domestic animals. Pica-11: The soil texture is coarse sandy with a hardened carbonate horizon (compare Picture4). The clast content is 10-20%; the organic content is low. Contamination is possible from pesticides. Pica-12: Reference sample for Pica11. The soil texture is coarse sandy with a hardened carbonate horizon (compare Picture4). The clast content is 10-20%; the organic content is low. Contamination is possible from pesticides. Pica-13: The sampling point is in the schoolyard, just next to the air sampler. The texture is coarse sandy. The clast content is 0-10%, the organic content 2%. Contamination is possible from the school activities and the former land-use, a scrap deposit. The distribution of the arsenic in the area of Pica is very inhomogeneous (see map). There is no clear tendency for areas with a distinctively higher or lower As content than can be explained geologically. The direct anthropogenic pollution is expected to be low and is mainly caused by pesticides from the citrus fruit plantations. The higher As peaks than average in Pica 2 and Pica 4 are very local anomalies. All the surrounding sampling points show a considerably lower As-content. The strong winds in the area rather tend to the conclusion that the As distribution should be very homogenous in the topsoil layer. Except for Pica 2 and 4 the As content in the area of Pica’s soils present a low variation of around 20%. The lowest arsenic content is in the sand dune sample (Pica 3). Sand dunes exclusively consist of material that is transported by the wind; therefore we expected a rather high content of anthropogenic As in the sand dune. The low As content in the sand dune and the inhomogeneous distribution of the As in general suggest that the breathable particles that are transported by the wind play a minor role in the soil pollution. The dried leaves from the citrus plantations might lead to a very local As contamination while the wind distributes them over the area. The irregularity of their distribution and deposition might lead to the described As anomalies.


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4.2 Quillagua


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Quillagua is situated in a valley on the lower terrace of the Rio Loa. The local geology consists of intercalated lacustrine and fluvio-lacustrine sediments, which are overlain by evaporites. Some carbonates and gypsum of this trough are found on the plain surface just North of Quillagua. The Western terraces of the Rio Loa consist of fluvial sediments with volcanic intercalations. The surroundings of Quillagua are of Jurassic limestones, tertiary volcanites and quaternary sediments and evaporites. The Jurassic limestone belongs mainly to the Cordillera de Domeyko (East of Quillagua) and covers a large area in the Río Loa catchment between Calama and Quillagua (210 and 220W). Westwards from the Cordillera del Domeyko the limestones disappear under huge alluvial fans. The largest of these fans is the Arcas fan whose distal points reach Quillagua. The limestone appears again in some small outcrops that surround Quillagua North-West-South. In the West of Quillagua Cretaceous intrusions are predominating. The intrusions form a small mountain chain situated just E of the Coastal Cordillera (see also Dörr et al., 1995; May et al., 1995; Jensen et al., 1995; Sáez et al., 1995 and Skarmenta et al., 1981). The water of the Rio Loa in Quillagua is extremely salty and has a very high As content. This contamination is not only directly from industrial pollution but mostly a secondary phenomenon. The natural As and salt content of the river Loa is very high. The strong evaporation in the desert causes the river natural high water losses in its course. Normally the water would freshen up by groundwater inflow, but this is nowadays very restricted because of industrial pumping activities along the banks of the river course. This has the effect that water level is very low and the amount of minerals in the water rises continuously (see also Fritsch, et al., 1999). One effect of the low groundwater level is that in earlier times Quillagua produced and exported Alfalfa, a plant that has a relatively high salt tolerance. Nowadays the Alfalfa production is nearly terminated and the plant must be imported. For more information about Quillagua and the Rio Loa catchment area see Fritsch et al., 1999.

4.2.1 Quillagua sampling points Quilla-1: Altitude: 790 m.a.s.l. The sampling point is located just north of Quillagua. The texture of the sample is coarse sandy-silty and it shows a high content of carbonates (Picture 11). The clast is 20-40% and the organic content is low. The groundwater level is >10m deep. There is no land use; a possible contamination source is the road. Quilla-2: The material is coarse sandy, 20-40% of clasts and a low organic content. The soil has a hard cover of carbonates and evaporates (Picture12). There is no land use; a possible contamination source is the road. Quilla-3: The sampling site is situated in a small Algarrobo (carob tree) forest called Monte de Oro. The soil texture is fine sandy-silty, the clast 0-10% and the organic content is low (Picture13). Possible contaminations include the road, eventual traffic and animals.


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Quilla-4: On a slope along the railway Iquique-Baquedano, north of Pica. The spot lies in the tertiary lime sediments. The soil is fine sandy-silty, the clast top 20-40%. Low organic content. Quilla-5 and Quilla-S: The sampling spot lies on the quaternary river terrace in one of the last fields under agricultural use in Pica. The field was just burnt a few days before the sampling (overview on the farm Picture 15, detail Picture 16). The texture of the soil is loamy-silty; the clast in the top and the subsoil 20-30% and the organic content is low. Contamination sources are the agricultural use and ashes. Quilla-6: The sampling site lies just above Quillagua, in the Tertiary lime sediments (Picture 17). The soil texture is sandy-silty, the clast content 20-30%, no organic content. There is no land use; a possible contamination source is the road. Quilla-7: The “off-road sample” is located in the Quillagua granite. The sampling point is in an isolated valley about 4km west of Quillagua. The underlying sediments are lacustrine, the overburden alluvial fans (see Picture 18). The wind is strong and causes strong deflation. Therefore the accumulation of stones and pebbles on the soil surface. The soil texture is sandy and the clast content 10-20%. There is no organic content and no direct sources of contamination. Quilla-8: Picture 19. The sample is close to the Panamericana, the underlying geology tertiary lime sediments. The texture is sandy-silty, the clast 20-40% with no organic content. A possible source of contamination is the Panamericana. Quilla-9: The sample is from the quaternary terraces of the Rio Loa, compare Pictures 20 (overview riverbed and terraces north of Pica) and 21 (sampling point). The terraces are 15-20m high. The materials in some of the layers contain poorly rounded material that was deposited by quick debris flows. The soil texture is sandy, the clast content 10-20%. The organic content is low and there is no direct contamination. Quilla10: In the riverbed of the Rio Loa, see Picture 22. The soil texture is loamy-sandy and the clast 10-20%. The humus content is low and the organic content is high. The possible sources of contamination come from the river sediments, especially from the flooding that occurred after heavy rainfalls in 1997 (compare Fritsch et al., 1999). Quilla-11: The sampling point is in the east of Quillagua, next to the cemetery (Picture23). The parent material is of tertiary lime sediments. The texture is sandy and the clasts 10-20%. There is no organic content and the possible sources of contamination are from the cemetery activities. Quilla-12: The sampling point is in the schoolyard, just next to the air sampler. The texture is coarse sand-loamy, the clasts 30-40%. The organic material is low and the possible sources of contamination come from the school activities.


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The analysis of the field recordings, the soil data and the map lead to a correction of the Quillagua map presented in this report: During the field work we recorded that the sampling points Quilla-1 and 2 are on the quaternary river banks of the Rio Loa, the sites 3 and 4 on the tertiary lime sediments (compare with the corresponding Pictures). The map of Quillagua in this report suggests that Quilla-2 lies in the tertiary calcareous limestone and Quilla-4 in the Quaternary. These mistakes derive from wrong GPS results or mistakes in the digitised maps. The distribution of the arsenic in Quillagua shows a very clear tendency: The As contents in the samples in the quaternary alluvial of the Rio Loa are very much higher than those of the surrounding samples from the tertiary sediments or the granite. The schoolyard has a lower As content, but consists of different parent material than the quaternary sediments. In general the mean arsenic content in Quillagua is far higher than in all the other sampling stations. This is partly due to geological factors because the natural As in the whole Rio Loa basin is exceptionally high. The elevated As contents in the Quaternary terraces come from industrial pollution after flooding events and from the industrial pumping of the acquifers explained earlier in this text. The results of Quillagua also lead to the conclusion that the aeolian deposition of breathable arsenic plays a minor role in the overall As pollution of the soils.


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4.3 Toconao


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Toconao is located East of Chile’s largest salt lake, the “Salar de Atacama” and lies in a closed hydrological basin at the foot of the Andes. The slopes to the East of Toconao are composed of different ignimbrites. The underlying recent geology consists of lacustrine layers. The salt lake was formed several thousands of years ago at the end of the quaternary ice age. The water of the lake contains a lot of minerals washed out from the volcanic rocks. The closed basin structure of the Salar de Atacama (no outflow of water) and the climatic conditions of the Atacama desert led to the evaporation the greater part of the lake. The Salar de Atacama consists of different types of evaporites. The salt lake is still active and does not dry out entirely due to the continuos inflow of groundwater from melted snow of the high Andes. The groundwater rises to the surface of the lake and evaporates there, forming new salt crusts. The melting water also contains a lot of minerals from volcanic rocks. The quaternary overburden around the Salar de Atacama is alluvial (see also Bevacqua et al., 1995 and Ramirez et al., 1995). Normally all the areas surrounding Toconao are covered with of boulders, rocks and pebbles because the finer materials, sand, silt and clay, are deflated by strong winds. Places where the boulders are still buried in the sand consist of younger sediments from periodically flowing rivers and/or alluvial fans that are more recent and/or still active; the wind has not yet taken the sand away. The project team tried to take samples of the various geomorphological forms of different ages.

4.3.1 Toconao sampling points Toco-1 and Toco-S: Altitude 2480m.a.s.l. The sampling site consists of lake sediments overlain by quaternary alluvial material. (Pictures 25 and 26). The Picture of the subsoil sample shows the lacustrine character of the sediments. The texture of the topsoil is coarse sandy, the subsoil texture is fine sandy-clayey. The material in the subsoil shows some carbonate crusts. The clast in the topsoil is 10-20%, in the subsoil 0%. There is no organic content and probable pollution might come from the road. Toco-2: The soil texture of this spot is silty-sandy and the clast content is 10-20%. There is no organic content and the probable source of contamination is the road (Picture 27). Toco-3: The surface of the soil shows a very different pattern from Toco-2 (Picture 28). Here are far more rocks and pebbles on the surface that clearly show strong deflation effects. The soil texture is sandy and the clast content in the soil is 10%. There is no organic matter and direct contamination is probable from the road. Toco-4: The sampling spot shows a different surface pattern Toco-3 because there are strong deflation effects but no major rocks on the surface (Picture 29). Geomorphologically this spot lies on a middle bank of two quebradas and can be reached by occasional floods. The soil texture is fine sandy with rounded gravel and the clast content is 20%; there is no organic content and the road is the only direct pollution source.


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Toco-5: The soil texture is fine sandy, the clast content 10-20%; there is no organic content and the road is a possible contamination source. Picture 30 shows the sampling devices and the sample in the plastic bag. Toco-6: This sampling point clearly shows the effect of wind deflation. We spotted the riverbed of the quebrada, clearly marked by the dried up plants, from sampling point 5 and drove back to find an ideal sampling point. Picture 31 shows an overview on the site, Picture 32 is a close up. A clear line marks the difference between younger and older riverbed sediments. The younger surface is indicated by the lack of a stone cover because the deflation did not yet have a great impact on these younger sediments. The soil texture is the same as in Toco-5. Toco-7: The soil texture is the same as in Toco-5 and Toco-6 (Picture 33). Toco-8: This sampling spot lies close to the shoreline of the former lake that covered the area. Picture 34 shows an outcrop with intersected alluvial and lacustrine sediments. The boulders on the surface show alluvial fan sediments, the stones are residual from deflation. The texture of the sample is sandy, the clast content 20-40%. There is no organic content and no direct pollution. Toco-9: This is the highest sampling point over Toconao (Picture 35). The rocks on the surface are weathered ignimbrites. The wind is very strong in this area; there are no fine particles at all between the stones on the surface. We have sampled the fine material under the stone cover. The texture is fine sandy-silty, the clast content 40%; there is no organic content and no direct pollution. Toco-10: The parent rock material from this sample is alluvial material from the Cajón ignimbrite. The texture is sandy-silty, 10-20% clast content and no organic material. A possible contamination source is the road. Toco-11: The soil is sandy; the clast content is 20-40% with no organic content and the road as a possible source of contamination. Toco-12: The sampling site is similar to Toco-6 because it is part of a quebrada. The sediments of this quebrada are of different parent material than Toco-6. It has a fine sand cover and the plants indicates periodically flowing surface or surface near groundwater (see Picture 36). The soil is sandy and the clast content10%. The organic content is low and direct contamination is possible from the road. Toco-13: In the Schoolyard. The sample is taken just under the spot of the air sampler. The texture is sandy, the clast content 20-40%. The organic content is low and the direct contamination comes from school activities. The distribution of the arsenic content in Toconao follows an interesting pattern. The arsenic content in the subsoil sample is higher than in all the other samples. Taking the climatic conditions into consideration, there is no great inflow of anthropogenic arsenic


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into the soil. This means that the high arsenic content in the lake sediments have accumulated in the period of the forming and drying up of the lake. These sediments were later covered by alluvial material. The lowest arsenic contents are found in Toco-3 and Toco-6. Both of these points are not located on the typical and average surface that surrounds Toconao. Toco-3 lies in an area with rather big rocks on its surface. The rocks show a very strong influence of wind erosion. This is an indicator that this area is older than the surrounding ones. The wind has had more time to blow the sand away and shape the rocks than in other areas. Toco-6 on the other hand is a very much younger area than the surrounding. The other very young sediment sampled in Toconao, the sampling point 12, has a different geological background, therefore it is not directly comparable to Toco-6. It shows the same range of concentrations as the other two sampling points with this geological background, Toco-10 and 11. The alluvial processes play a more important role in the distribution of the breathable As content in the soil than aeolian processes.


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4.4 Diego de Almagro


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Diego de Almagro is located between the quaternary terrace system of the Rio Salado in the south and andesine volcanic rocks in the north. Just north of Diego de Almagro is an extensive alluvial fan. The air sampling station is in a school that lies on the contact zone of the alluvial fan with the higher river terrace. Other geological units in the area of Diego de Almagro consist of andesine lava; they form considerable copper deposits which were mined in passed years; as well as tertiary alluvial and evaporitic deposits (see also Godoy et al., 1998). The main winds in the city of Diego de Almagro follow the valley of the Rio Salado. In the mornings there is a strong wind towards the sea, in the evening the winds come from the sea. North of the city, just behind the mountain range, is a rather large aeolian deposit. The material of this deposit consists mainly of sand dunes. The fine material is transported here and to Diego de Almagro from the desert and the seaside, and it presumably contains material of old tailings from the El Salvador mine and smelter. These tailings were washed down the Rio Salado until 1994, and nowadays form an extensive artificial beach in Chañaral. The tailings are drying out and the strong local winds transport parts of them back into the hinterland. The possible air contamination of these old tailings should be considered, also in the centre of Diego de Almagro. Since 1994 the El Salvador tailings are deposited in the tailing pond “Tranque Pampa Austral”, approx. 15km North of Diego de Almagro (see Picture 45). This tailing pond is so new that it does not appear yet in the geological maps. A source of local air pollution could be a small mining cooperation that operates just West of the city. The project team could experience that the smell nuisance of this cooperative is very high. If not indicated otherwise, possible direct pollution might come from the terminated mining activities and road traffic. Atmospheric pollution is possible from several larger and smaller smelters and from the tailings in Chañaral. There is no organic content in the topsoil in the whole area.

4.4.1 Diego de Almagro sampling points Diego-1: Altitude: 750m.a.s.l. At the foot of the Cerro Tres Cruces (see Picture 37). The area is below an abandoned copper mine. The area is covered with rocks that contain traces of copper, Atacamita, Iron and Crizocola. The texture of the soil is sandy, the clast content 10-20%. Diego-2: Also this sampling point is on the slope of the Cerro Tres Cruces (Picture 39). Opposite of the sampling point is the plant of the small mining cooperative that is mentioned earlier in this text. The soil texture is the same as in Toco-1. Diego-3: The sampling point is on a small alluvial cone of a hill without mining activities (Picture 38). The soil texture is sandy, the clast content 20-40%. Diego-4: The sampling point lies on an alluvial fan than has brought material from further inside the mountain range (Picture 40). The soil texture is sandy and the clast content 10-20%.


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Diego-5: The sampling point is in the west of Diego, in the quaternary alluvial banks of the Rio Salado. The soil texture is loamy-sandy and the clast content 10-20% (Picture40) Diego-6 and Diego-S: The texture of the sample is sandy, the clast content 10%. Picture 42 shows roots in the subsoil (<25cm)that indicate occasional rainfall in the area. This was the only sample in Diego de Almagro that contained organic matter. In >50cm depth appear pebbles. Diego-7: This is an “off-road” sample that was taken from a road that is not marked in the map. We drove this road and crossed the mountain range north of Diego de Almagro to take a sample that is not in the line of the direct wind effect of the Rio Salado Valley. The parent rocks of the sample are of andesine volcanic material so that the sample is comparable to those taken in the valley. The texture of the sample is coarse sand, the clast >50%. Diego-8: The sampling point 8 has the same soil texture as Diego-7 (Picture 45). Diego-9: The soil texture is sandy and the clast 10-20%. Diego-10: This sampling spot is located on the other side of the mountain range that borders the Rio Salado valley on the northern side. The texture is sandy and the clast 20-40%. Diego-11: The sampling spot is just above Diego de Almagro (see Picture 46). The parent bedrock geology is not quaternary as indicated in the map; it consists of andesine volcanites. The place is extremely windy. The soil structure is sandy, the clast >50%. Diego-12: The sampling place is in the southern part of Diego, on the vast plain terrace system of the Rio Salado. The soil texture is sandy, the clast 20-40%. Diego-13: Compare with Picture 48. The sample has the same properties as Diego-12. Diego-14. In the schoolyard, approx. 10m from the soil sampler. The soil is sandy, the clast content >50%. The distribution of the breathable arsenic in Diego de Almagro follows a different pattern than the other sampling sites. The highest As concentrations are found along the main riverbed. The samples S, 2, 3, 4 and 5 were taken from the distal points of alluvial cones that reach the riverbed, not from terrace material. The river-terrace samples 1, 12 and 13 have a rather low As content. The subsoil sample Diego-S shows a that the geogenic arsenic is very high in the area. In Diego de Almagro the water is the main transporting agent for the breathable As in the topsoil.


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4.5 Vallenar


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Vallenar lies on the lower quaternary terrace of the Rio Huasco that flows in a deep valley and shows a distinct terrace system. The height difference between the lowest and the upper terrace is over 120m; the highest terraces belong to the upper tertiary (Moscoso et al., 1982). One of those highest terraces was sampled during the Conama project and showed some soil forming processes, such as oxidisation. This indicates that the terraces have passed through a more humid climate than the present one because the present dry desert climate does not allow this kind of soil forming processes. All the soil samples in this area were taken on river and mountain creek terraces. Vallenar is a more populated area than the more northern sampling sites and most of the spots surrounding the city are or have been under anthropogenic use. It was very difficult to find undisturbed soils. The least disturbed soils were found on the floodplain, just above the Rio Huasco riverbed.

4.5.1 Vallenar sampling sites Valle-1: Altitude 400m.a.s.l. The sampling site lies at the foot of the first high terrace, in the city of Vallenar. The terrace bears many boulders (see Picture 49). The soil texture is sandy, the clast content >50%. The organic content is low and possible contamination sources comprise several urban activities, such as traffic, dumping of garbage and others. Valle-2: The sampling point is located on the first high terrace of the Rio Huasco (see Picture 50). The former land use of this spot was pasture for domestic animals until approx. 15 years ago. The centre of Picture 50 shows the ditch of a former irrigation channel. The soil is sandy, the clast content 15-40%. The organic content is low and the possible contamination sources comprise the several urban impacts. Valle-3: (Picture 51). The site is located on the second high terrace of the Rio Huasco; the Picture shows the third terrace in the background. The soil texture is the same as in Valle-2. Additional contamination sources are a chalk fabric 1km to the north and a waste deposit located 1km to the east. Valle-4 and Valle-S: The sampling spot is located on the highest terrace of the Rio Huasco, approx. 120 m above the city. Picture 52 shows the sampling point and the Chehueque volcano in the background. The sampling spot is located so close to the road because it was the only spot without industrial land use in the surrounding. The soil texture is sandy-loamy, the clast content 15-40%. The organic content is low and the possible contamination sources identical to those of the former sampling sites. Picture 53 shows the subsoil sample. Valle-5: The sampling spot is located on the first high terrace of the Rio Huasco in an irrigated pasture land. The site is regularly burned. The soil is sandy-loamy and the clast content 15-40%. Valle-6: Picture 62 shows an overview of the sampling spot 6, the terrace system of the Rio Huasco and Vallenar in the centre of the Picture. The sampling spot lies on the second high river terrace. The soil texture is the same as in Valle-5.


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Valle-7: The site is in the western outskirts of Vallenar on the lowest river terrace (see Picture 55). The soil texture is loamy-sand and the clast content 15-40%. Valle 8: Picture 63 shows an overview on the sampling spot, from the west into the city of Vallenar. The soil texture is the same as in Valle-7. Valle-9: The sampling point 9 is a so-called "off-road" sample because it does not lie in the main geological units of the other sampling points. Valle-9 (see Picture 56) is taken from a very small creek which sediments contain a lot of pyrite. The soil texture is the only one of the Vallenar area which is purely sandy and has only 0-2% of clasts. There is no organic content and no direct source of pollution. Valle-10: The sampling spot lies on volcanic rocks that are not marked on the geological map, probably due to the small scale (see Picture 57). Picture 58 shows an overview over the sampling site towards the north. The spot lies 20m above the river, in the background is the corresponding northern first high terrace. The soil texture is loamy, the clast content15-40% and the organic content is high. Valle-11: Picture 60 shows sampling point 11. The land use is pasture for animals. Geomorphologically the site is on the lowest river terrace that is flooded irregularly. The soil is loamy, the clast content 5-10% and the organic content 30%. Contamination is possible from the animals. Valle-12: The sampling spot lies in the junction of the migrating riverbed of the Rio Huasco and a small creek (see Picture 59). The Picture points to the west and shows that the creek has recently cut itself into the lower terrace of the Rio Huasco. The texture of the creek sediments is sandy-loamy and the clast content >50%. Valle-13: Picture 61 shows the sampling point in the schoolyard. The house in front is the base of the air sampler. The texture is sandy-loamy, the clast content 15-40% and the organic content 20%. The As distribution in Vallenar follows a very clear pattern: The highest concentrations are found in the quaternary sediments of the river's lowest and first high terrace. The samples Valle-10 and 12 show a lower As concentration than the other samples because sample 10 lies on a volcanic outcrop and sample 12 is from the sediments of a small creek that discharges into the Rio Huasco (compare above). The “off-road” sample which is also not from Rio Huasco sediments but from a creek that has deposited material from another geological unit, also shows a lower As concentration. The distribution of the As over the river terraces clearly indicates that water and not the air is the main transporting media of As in Vallenar.


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4.6 Quillota


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Quillota lies on quaternary terraces belonging the Rio Aconcagua (Rivano, S. et al., 1993 and Skarmenta, J. and Mainovic, N., 1981). Besides the “offroad” sample all the sampling spots are on the lower terrace and the floodplains of the river. The predominating material of the river terraces is alluvial material originating from the higher Andes. Weathered material from the local geological units is intercalated with the terraces. The whole area is under the influence of human beings; either by built up areas or agriculture. It was impossible to find any undisturbed soils. The project team therefore tried to find most representative and/or less disturbed soils. Main sources of contamination are pesticides used in the agriculture, such as "Monitor 600, Baytroid and Tamarón". According to the information from people in the agricultural school, the main component of the pesticides is methyl bromid (CH3Br) which is very toxic. They also mentioned that the pesticides have a high As content. The farmers expressed that they hardly use pesticides and that none of the pesticides contaminates the soil, which seems to be a rather unreliable information because the project team observed direct pesticide spraying during the sampling.

4.6.1. Quillota sampling points Quillo-1: Altitude 130 m.a.s.l. The soil texture is loamy-sandy, the clast 0-2%; the humus content is low, the organic content high (Picture 64). The fine material of the soil sample belongs to a fine overburden over the gravel of the river terrace. This fine material is an indicator that floods sometimes reach the area. The point is so far away from the riverbed that only fine material can be sedimented here. Quillo-2: The soil texture is loamy, the clast content 0-2%; raw humus and high organic content (picture 65). Quillo-3: The soil texture is loamy-sandy with a clast content of 15-40%. There is no humus and high organic content (picture 66). Quillo-4: The soil texture is loamy-clayey and the clast content 15-40%. There is no humus and high organic content (picture 67). Quillo-5: This sampling site is on the flood bed the Rio Aconcagua, outside of the agricultural land. The Picture 70 shows an overview on the site. A dam prevents the spring floods from reaching the agricultural land (compare also Picture 71). The soil is sandy and even though boulders are abundant, the clast content is rather low, 0-2%. There no humus and a low organic content (Picture 69). Quillo-6: The sampling spot lies close to the river Aconcagua that runs behind the dam (picture 71). The river smells very bad because of its heavy pollution. Earlier floods from this river must have caused very strong contamination to the surrounding soils. The texture of the sample is sandy-loamy and the clast content over 50%. There is no humus and a low organic content.


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Quillo-7: This sampling spot presents the same overburden of fine material over the terrace as the sampling spots Quillo-1 and 2. The present land use is pastureland. Traces of ashes indicate a regular burning of the area which eventually is under agricultural use (compare Picture's 72 and 73). The soil texture is loamy sand with a clast content of 5-10%. There is little raw humus and a high organic content. Quillo-8: The sampling site is located next to a ditch that leads along the main road (Picture 74). The texture is loamy and the clast content 15-40%. There is no humus and a low organic content. Quillo-S: The sample was taken from a very fresh excavation (Picture 68). The soil texture is sandy loamy with a clast content of 2-15%. The organic content is low. Quillo-9: The sample is located in a farmland similar to Quillo 2, 3 and 4. A loamy overburden over the terrace gravel is about 60 cm thick. The soil is loamy and the clast content 15-40%. There is no humus and a high organic content. Quillo-10: The sample lies in a cornfield (compare Picture 75). The soil texture is the same as in sample Quillo-9. Quillo-11: This is the "off-road sample" of the area. It is situated in the granite intrusion of the coastal cordillera (syenite granite). Picture 76 shows an overview upon the valley of the Rio Aconcagua from the south. Picture 77 shows a close up of the heavily weathered granite. The soil structure is coarse sandy, the clast content is 5-10%. There is no humus and a low organic content. Quillo-12: The sample was taken in the schoolyard, about 100m from the air sampler. The texture is loamy and the clast content 15-40%. There is no humus and a low organic content. The As content in the soils of Quillagua is difficult to interpret. The highest As content was measured in the subsoil sample where the As is most probably of natural origin. The topsoil samples show a great variation in the As content. Most probably the pesticides used in the agriculture play a major role in the local As distribution.


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4.7 Talca


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The sampling station is located close to Linares and lies on quaternary alluvial terraces of the Rio Maule. All the samples have been taken on the alluvial sediments of this river or creeks of the same river system (Hauser, A. (1995). As in Quillota, the material originates from the higher Andes. Also here it was impossible to find any undisturbed soil; the samples were exclusively taken from areas under agricultural use. Many farmers assured at several sites that their fields are under agricultural use just recently and that the soil has not been ploughed or moved. They also expressed that they do not use a lot of pesticides. The information appears to be rather unreliable. In general it can be expected that all the samples from Talca have had a strong anthropogenic, especially agricultural, impact.

4.7.1 Talca sampling points Talca-1: The sample lies on a field under wild vegetation. Fields with different crops surround it. The soil texture is loamy and the clast content of 15-40%. The organic content is low. Talca-2 and Talca-S: These samples lie along an irrigation channel that runs parallel to the Rio Maule. The land use of the area is nowadays pastureland for different domestic animals. The topsoil sample is loamy and has a clast content of 15-40%. There is little humus and a high organic content. The texture of the subsoil sample is loamy and the clast content 5-10%. There is no humus and a low organic content. Talca-3 to Talca 12: The whole area is very homogeneous. All the samples were taken from land under agricultural use. Animals frequently graze the sites. All the samples have a soil texture that is loamy and a clast content of 15-40%. Like in Quillota, we expect that the impact of pesticides and the agricultural land use activities play the major role in the local As distribution in the soil.


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5. Interpretation of the soil data This chapter analyses the distribution of some elements relevant towards environmental pollution in the soils surrounding the air sampling stations which helps in indentifying the sources and the media of transport of pollutants. The analysis of the As distributed in the soils shows that the northern Chilean sampling sites have a high amount of As in the soils, some a very high one. One assumption was that a higher As content in the soil will lead to a higher As content in the surrounding atmosphere because the As content in the soil of a sampling station would have a direct impact upon the As suspended in the air at the same location. Nevertheless, the results from the air samplers show that the geogenic As content in the soil has a rather small impact on the As content in the air. Industrial emissions are the main source of the suspended As particles in the atmosphere. On the other hand, aeolian transport of the breathable As particles has no major impact on soil contamination. The As content in the soil is mainly controlled by alluvial sedimentation processes. In this project the elemental concentrations in the soil samples were compared to the concentrations in the PM10-particles. To assure the comparability of the results from different sample materials, the samples were dissolved by using a strong acid leaching, which is able to totally dissolve most minerals in the samples. Thus the analytical results are very close to the total concentrations of elements in the samples. The elements that are both abundant in the natural Chilean geology and anthropogenical emissions (Na, Fe, Al and others) are therefore not respected in the analisis of geogenic or anthropogenic enrichment. The natural average concentrations of the elements discussed in this chapter are well studied (Koljonen 1992). An excess to the average natural amount of an element is assumed to indicate anthropogenical origins. The figures show the median concentration of all the topsoil samples from one sampling station and the concentration of the corresponding subsoil sample.


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Figure 3: Distribution of Copper in the soil samples Copper is a vital nutrient to all living forms but an excess of copper can be toxic to both plants and animals. In soils Cu is normally bound to the organic substance as well as Mn- and Fe-oxides. Usually the solubility and availability of Cu rises in pH values <5 (Scheffer et al., 1989). The average amount of copper in the world soils is 25 mg/kg (Koljonen, 1992). Figure 3 shows that the amount of copper is generally elevated in all the soil sampling sites. Some of the copper contents in the soils are so high that they become toxical to plants and animals. This can lead to considerable loss of agricultural yield and illnesses. The anthropogenic sources of copper in the environment are mainly the copper industry, sludges and pesticides (Scheffer, 1989). Figure 3 leads to the conclusion that the elevated copper in the most of the sampling sites comes from the use of pesticides in agriculture. There are two exceptions: In Toconao the high copper content in the topsoil is really considerable and its origin unclear. The high copper content in Diego de Almagro comes from the past and present heavy copper mining in the surroundings of the city and in the catchment area of the Rio Salado.

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Figure 4: Distribution of Zinc in the soil samples

Figure 5: Distribution of Cadmium in the soil samples Zinc and Cadmium are in a relatively constant realtionship to each other because they are chemically strongly related. In rocks the relationship is around 500 and in soils around 100 (Scheffer et al., 1989). Therefore the two elements are discussed together in this chapter. Zinc is an indispensable trace element for human beings, animals and plants. Too high Zn concentrations can be toxical to plants and microorganisms. In pH regimes over 6.5 Zinc

Zn

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is normally strongly bound to organic compounds in the soils; at a pH under 5 it is highly mobile and available for the plants (these figures could be different for the northern Chilean soils because of the low organic content). Anthropogenic Zn is mostly emitted from heavy industries, especially the iron and steel production uses it in the corrosion protection. In general the recommended limit value for Zn is of 300 mg/kg. (Scheffer et al., 1989). The average distribution of Zn in the world’s soils is of 70 mg/kg (Koljonen 1992). Cadmium is no nutrient and it is toxic to all life forms. The average distribution of Cd is of 0.3mg/kg in the world wide comparison (Koljonen et al., 1992). Scheffer et al. (1989) mentions that the Cd availability rises with lower pH values and that 0.1mg/l of cadmiun in the soil solution already has toxical effects on plants. Example: The suggested limit value in soils for Cd at pH 7 is 2.2 mg/kg and for pH 6 1.1 mg/kg. The main sources of Cadmiun are heavy industry, sludges, traffic and P-fertilizers (Scheffer et al., 1989). As mentioned earlier, natural Zn and Cd are strongly linked to each other. Also the anthropogenical emissions often contain both Cd and Zn but not necessarily in the same relationship. Figure 4 and 5 show that the natural relationship between the two elements is very well presented in most of the sampling sites. The relation between the two elements is disturbed in Pica, Quillagua and Toconao, which indicates an anthropogenical impact. In general the values for both Cd and Zn do not exceed recommended critical loads. Figure 6: Distribution of lead in the soil samples

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Lead is not as toxical as Cd but in high concentrations it is dangerous to the health of human beings and animals. (Scheffer et al., 1989). Globally the transportation of Pb occurs mainly the atmosphere. Over 60% of the emitted Pb is from leaded gasoline; Other major Pb sources are ore smelters. In comparison to As and Zn, lead is rather immobile. The availability of lead rises strongly at low pH values around 4, depending on the organic matter: The higher the organic matter, the lesser the availability. Because of its immobility, the general limit value recommendation is 100mg/kg of Pb (Scheffer et al., 1989). The world’s average amount of Pb in soils is 17 mg/kg (Koljonen et al., 1992). Figure 6 shows that incomparison to this number, the lead content in the subsoil is elevated in over 50% of the sampled soils. Quillagua, which is the only sampling area that is not directly crossed by a major road and has not much traffic, lies in vicinity of a large smelter. Since the soils in Quillagua have a lower Pb content than most of the other sampling points, this indicates that the traffic causes most of the lead contamination in all

the sampled soils. Figure 7: Distribution of S in the soil samples Sulfur is a basic nutrient to plants, animals and human beings. An excess of sulphur is toxical to all life forms. Anthropogenical Sulfur is mostly emitted by heavy industries and transported in the atmosphere (Scheffer et al., 1989). The average distribution of S in world’s soils is of 180 +/-140 mg/kg (Koljonen et al., 1992). According to Scheffer et al. (1989), a concentration of over 300 mg/kg cannot be tolerated by many agricultural plants and should therefore be avoided. Figure 5 shows that the S concentration in the topsoil of Quillagua is exeptionally high and that the soils of Pica, Toconao and Diego also have elevated S-levels.

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0.002000.004000.006000.008000.00

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Figure 8: Phosphorous in the soil samples Phosphorous is a vital nutrient for all life forms and it is widely used as a fertilizer in agriculture. The figure 7 shows a clear tendency of higher P concentrations in Quillota and Talca. This tendency is even clearer when calculating average values. The extensive agricultural land use made it difficult to find undisturbed soils in Quillota and Talca. The higher phosphorous content in these soils is a clear indicator of the agricultural land use. Hence many fertilizers and pesticides also contain arsenic, the As content in these southern most sampling sites is difficult to interpret. The agricultural land use probably has a very high impact and a soil analysis would require a more detailed geochemical study. The conclusion of this chapter is that the soil sampling can attribute important information to the air sampling and modelling because it can help to explain the natural distribution of elements as well as anomalies that are caused by anthropogenical influence. Furthermore, the soil sampling could give a good overview on the industries’ impact upon Chilean soils, even on large distances from the potential emitters. Unfortunately it was not possible during this project to take enough soil samples for a representative statistical soil analysis. We strongly recommend to perform a larger soil sampling project in combination with a further air sampling and PM distribution modelling. This will help to understand the geochemical baseline of the Chilean soils and will clearly depict present and historical contaminations which can be relevant for the health of human beings, animals and plants.

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6. Glossary of some geological and pedological terms - Aeolian: Belonging to or caused by wind. Sand dunes are aeolian deposits. - Alluvial cones: Cones that consist of weathered material and lie at the foot of a

mountain or a hill. The transporting agent of the material is water (alluvial). - Andesite: Fine grained, dark coloured volcanic rock. - Clast: The amount of stones and pebbles in a soil in % of the fine soil material. The

clast content can help to explain the sedimentary regime: If the clast content is low, the energy of the sedimentation was not strong enough to transport a lot of big material. The clast content also gives explanation towards the parent rock material and its state of weathering.

- Debris flow: Very quickly moving mass of mud, soil and rock fragments. - Deflation: removal of material by the action of wind - Evaporite: Sediment deposited from a saline solution as a result of partial or total

evaporation of water. - Granite: Medium to coarse-grained rock solidified from melted material that

solidified at great depth. - Ignimbrite: Deposits of volcanic pyroclastic flows (clastic rock material from

volcanic explosions) - Lacustrine: Related to or produced (sedimented) by lakes - Organic content: Amount of organic material in the soil, in %. The organic content of

a soil can absorb and bound several contaminating elements, e.g. arsenic. - Quaternary: The earth’s youngest geological era, < 1 million years. The quaternary

was characterised by a glaciation period that ended +/- 12000 years ago. In northern and central Chile the glaciers glaciers the higher mountain ranges of the Andes. When the glaciers melted, large amounts of sediments were transported to the valleys, forming extensive alluvial cones and river terraces.

- Palaeozoic: Geological era, 570-225 million years ago. - Soil texture: In this report the soil texture describes the grain size of the soil which

gives an indication of its parent material, the sedimentation processes and its age in relation to the surrounding soils.

- Terrace: Sediment deposited by rivers - Tertiary: Second youngest of the earth’s geological era’s 65-1 million years before

today. It was mainly characterised by a more humid and warm climate than nowadays.


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7. Literature

- Araya Vergara, J. (1997): Evolución de la Depresión de Santiago junto a su Borde Occidental. In: Anales de la Sociedad Chilena de Ciencias Geográficas, p. 315 – 323, Santiago.

- Arias, J. (et al.), (1991): Atlas geoquimico al Noreste de Antofagsta, Chile: Resultados, en: Resumenes del Congreso Geologico Chileno, Santiago.

- Bevacqua, P and D.G. Chong (1995): The Salar de Atacama of Northern Chile: Evolution and Stratigraphy of its Nucleus. In: Recent and Ancient Lacustrine Systems in Convergent Margins, Glopals – IAS Meeting, Abstracts, p. 21, Antofagasta.

- Boric, R. (et al.), (1987): Geologia y Yacimientos Metaliferos de la Region de Antofagsta, Sectores Norte y Sur, 1:500 000. Servicio Nacional de Geologia y Mineria.

- Bruggen, J. (1916): Informe Preliminar acerca de la Geologia de la Falda occidental de los Andes al Oriente de Pica, Santiago.

- Bruggen, J. (1950): Fundamentos de la geologia de Chile, Santiago.

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and Ancient Lacustrine Systems in Convergent Margins, Glopals – IAS Meeting, Abstracts, p. 9, Antofagasta.

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APPENDICES

Appendix I: Chemical analyses

I.1. Soil samples 0.200 g of the sample was accurately weighed in a Teflon vessel and treated with strong nitric acid to decompose possibly existing organic matter in the sample. Nitric acid was evaporated in mild temperature, and the samples were digested by using hydrofluoric acid-perchloric acid treatment. The solutions were analysed by using an inductively coupled plasma-mass spectrometer (ICP-MS) and inductively coupled plasma-atomic emission spectrometer (ICP-AES). The method code of the Chemical laboratory for this method is 307MP. The analysed elements and their detection limits are shown in table 1. Table I.1. Elements determined from soil samples and their detection limits

Element Detection limit

Unit Method Code1


Unit Method Code1

Ag 2 mg/kg 307M Mn 10 mg/kg 307P Al 50 mg/kg 307P Mo 0.4 mg/kg 307M As 0.1 mg/kg 307M Na 150 mg/kg 307P Ba 1 mg/kg 307M Ni 2 mg/kg 307M Be 0.01 mg/kg 307M P 100 mg/kg 307P Bi 0.1 mg/kg 307M Pb 10 mg/kg 307M Br 10 mg/kg 307M Rb 0.5 mg/kg 307M Ca 100 mg/kg 307P S 50 mg/kg 307P Cd 0.05 mg/kg 307M Sb 0.4 mg/kg 307M Co 0.2 mg/kg 307M Sr 3 mg/kg 307M Cr 3 mg/kg 307M Th 0.2 mg/kg 307M Cu 1.5 mg/kg 307M Ti 10 mg/kg 307P Fe 100 mg/kg 307P Tl 0.01 mg/kg 307M K 100 mg/kg 307P U 0.04 mg/kg 307M Li 0.8 mg/kg 307M V 0.5 mg/kg 307M

Mg 50 mg/kg 307P Zn 5 mg/kg 307M 1The Method code letter M refers to ICP-MS-determination and letter P to ICP-AES-determination 5 % of the samples were digested and analysed as duplicate samples. Together with the samples, reagent blanks and certified reference materials were digested and analysed.


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I.2. PM10-samples The filter used for collection of the particles was folded and placed into a plastic test-tube. The particles in the filter were dissolved by using a mixture of hydrofluoric acid and nitric acid and the solutions were analysed by using ICP-MS-technique (Method code 317M). Together with the samples, reagent blanks and certified reference materials were digested and analysed. The analysed elements with their detection limits are shown in table 2. Table I.2. Elements determined from PM10-samples and their detection limits


Unit Method code


Unit Method code

Ag 0.001 µg 317M Mn 0.03 µg 317M Al 0.01 µg 317M Mo 0.005 µg 317M As 0.01 µg 317M Na 1 µg 317M B 0.05 µg 317M Ni 0.01 µg 317M Ba 0.01 µg 317M Pb 0.005 µg 317M Be 0.03 µg 317M Rb 0.001 µg 317M Bi 0.002 µg 317M S 0.03 mg 317M Br 0.02 µg 317M Sb 0.003 µg 317M Ca 2 µg 317M Se 0.05 µg 317M Cd 0.003 µg 317M Si 20 µg 317M Cl 0.1 mg 317M Sr 0.01 µg 317M Co 0.003 µg 317M Th 0.002 µg 317M Cr 0.04 µg 317M Ti 0.05 µg 317M Cu 0.005 µg 317M Tl 0.001 µg 317M Fe 0.5 µg 317M U 0.001 µg 317M K 1 µg 317M V 0.005 µg 317M Li 0.01 µg 317M Zn 0.03 µg 317M

Mg 0.05 µg 317M

I.3 Uncertainty estimation of the in analytical results of the soil samples The uncertainty in the analytical results of the soil samples was estimated by using standard deviation data from replicate samples and the results of the certified reference materials analysed together with the samples. For most elements, the uncertainty is dependent on the analyte level, and thus two estimations of the uncertainty level are given. In table 1 below, the estimates of uncertainty are given as percentages of the measured concentration.


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Table I.3: Uncertainty estimation of the in analytical results of the soil samples

Concentration of element in sample

mg/kg

Uncertainty in analytical result

%

Concentration of element in sample

mg/kg

Uncertainty in analytical result

% Ag 2-20 20 >20 10 Al 50-1000 20 >1000 10 As 0.1-2 20 >2 10 Ba 1-20 20 >20 10 Be 0.01-0.2 20 >0.2 10 Bi 0.1-2 20 >2 10 Br 10-100 20 >100 10 Ca 100-2000 20 >2000 10 Cd 0.05-1 20 >1 10 Co 0.2-4 20 >4 10 Cr 3-30 20 >30 10 Cu 2-15 20 >15 10 Fe >100 10 - - K >100 10 - - Li 1-16 20 >16 10 Mg >50 10 - - Mn >10 10 - - Mo 0.4-8 20 >8 10 Na >150 10 - - Ni 2-13 20 >13 10 P >100 10 - - Pb 10 20 >100 10 Rb 1-10 20 >10 10 Sb 0.4-8 20 >8 10 Sr 3-20 20 >60 10 Th 0.2-4 20 >4 10 Ti 10-200 20 >200 10 Tl 0.01-0.2 20 >0.2 10 U 0.04-0.8 20 >1 10 V 1-10 20 >10 10 Zn 5-10 20 >10 10 Example: Measured arsenic concentration in a sample is 1.5 mg/kg. The estimated uncertainty of the result in that concentration level is 20 % of the measured concentration. 20 % of 1,5 mg/kg is 0.3 mg/kg, and the correct result is estimated to lie between 1,2 - 1,8 mg/kg. If the measured arsenic concentration in sample is 200 mg/kg, the estimated uncertainty is 10 % of the measured concentration, and the correct result is estimated to be between 180-220 mg/kg.

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