Action C.1

ANALYTICAL DETERMINATION OF MOBILITY AND BIOAVAILABILITY OF POLLUTANTS

IN PILOT-SCALE FIELDS

Coordinator: Salvatore Di Rosa (ARPAC)

Personnel:Bruna Coletta, Diego Guglielmelli, Angela Vetromile (ARPAC)Paola Adamo, Maria A. Rao, Claudia Rocco (UNINA)

The long term stability of pollutants in soils subjected to bioremediation and phytostabilization can be predicted by selected environmental scenarios by conducting simple leaching tests and more detailed chemical extractions and by direct soil analysis using advanced spectroscopic techniques (Adamo and Zampella, 2007).Knowing what kind of compounds and molecular bonds prevail between pollutants and soil constituents, allows the prediction of their possible fate in soil-plant system.

Background

Adamo P., Zampella M. (2007) Chemical speciation to assess potentially toxic metals (PTMs) bioavailability and geochemical forms in polluted soils. In: (De Vivo B. et al. Eds.) Environmental geochemistry: Site characterization, data analysis, case histories, Elsevier.

“Bioremediation: Caratterizzazione Microbiologica di un sito contaminato da idrocarburi nella provincia di Napoli”. Biologi Italiani n. 7/2006,- S. Di Rosa, et al.

total or “pseudototal” content of trace elements in soil might minimize the risks

Mobility and bioavailability

Risk/toxicity

Remediation techniques

Management

Italian legislation (D.Lgs 152/06) based on total content

Objectives :

1. investigate the mobility/bioavailability of pollutants before, during and after the applied bioremediation processes;

2. test the effects of applied bioremediation processes on soil through its chemical and biological properties;

Analytical techniques for PTMs (Potentially Toxic Metals)

Determination PTMs total content

Official Chemical Methods for soil analysis (DM 13/09/99)H2 O2 pre-oxidation, Acid digestion by 3HCl+1HNO3

Determination PTMs bioavailability and mobility

Single chemical extraction procedures recommended by EU:0.05 M EDTA (pH 7.0)0.43 M acetic acid solutions

Three-stage sequential chemical extraction procedure recommended by EU:0.11 M acetic acid (step 1) 0.5 M hydroxylamine hydrochloride, pH 1.5 (step 2) 8.8 M hydrogen peroxide, then 1 M ammonium acetate, pH 2 (step 3)

Quality of measurements checked by reference materials CRM 700 and 701

The characterization of the level of pollution of PAHs, is performed through accelerated solvent extraction of soil samples, purification of the extract on a column of silica gel and subsequent determination of the concentration of organic pollutants by GC / MS (EPA Method 8270D).

Determination of the bioavailability of PAHs, in terms of resistance to desorption, will be carried out by single and sequential elutions from solid phase and analysis by GC/MS (EPA Method 8270D) (Instrumentation: Agilent GC model. 7890A/Detector MS 5975C).

Analytical techniques for PAHs

Leaching tests simulating the process of washing away from soil of metals and organic micro-pollutants (PAHs) by rain water will be carried out in laboratory.

On eluate, the following parameters will be determined:

Leaching tests

pH;

Cations (NH4

+, Na+, K+, Ca2+ e Mg2+) and anions (F-, Cl-, NO2-, NO3

-, SO42-

e PO43-) by ion chromatography (Dionex ICS 3000);

Total and Dissolved Organic Carbon (T.O.C and D.O.C.) by combustion analyzer with IR detector (Uni En 1484 – Instrumentation TOC VCHS Shimadzu);

PAHs, extraction on SPE membrane, purification on silica chromatographic column, analysis by GC-MS (EPA Method 8270D - Instrumentation: Agilent 7890A/5975C);

PTMs, after acidification of eluate with 2% HNO3 , by ICP-MS (Method EN ISO 17294-2).

Effects of bioremediation processes on soil chemical and biochemical properties and nutrient contents

Soil samples sieved at 2 mm mesh analyzed for:

particle-size distribution (by laser granulometry)pH in a 1:2.5 (w/v) soil/deionised water slurryorganic carbon and carbonates (total combustion)cation exchange capacity (CEC) (BaCl2 method)exchangeable bases (atomic absorption spectrometry)total-N (total combustion)available soil phosphorus (Olsen method)

In addition, microbial biomass carbon and activities of enzymes involved in the main soil biological functions (phosphatase, dehydrogenase, sulphatase, etc.) and known to be sensitive to the presence of heavy metals (sulphydryl or free amino groups at the active site) will be assayed on soils to evaluate the efficacy of the applied bioremediation process on the microbial and enzymatic parameters so far described (Rao et al., Journal of Soil Science and Plant Nutrition 10, 2010).

The majority of planned analytical determinations and measurements will be carried out at the:

ARPA Campania Regional Centre for Polluted Sites (CENTRO REGIONALE SITI CONTAMINATI or CRSC).

Single and sequential chemical extractions, and enzymatic activities will be carried out in the laboratory of Prof. Paola Adamo at the Department of Soil, Plant, Environment and Animal Production Sciences of Naples University Federico II.

Where

Laboratory analyses will be carried out on soil samples taken from selected field pilot experiments before (end of 1st project year), during and after ongoing bioremediation and phytostabilization actions.Moreover pollutant (mainly organic) content in soil will be measured also in support of action B1a of isolation and selection activity of bacteria strains and microbial community.

Timing

Chemical Monitoring Report 1 (start 31-12-2013): analytical results before bio- and phyto-remediation activity.

Chemical Monitoring Report 2 (intermediate 31-12-2015) and Chemical Monitoring Report 3 (end 31-01-2017): analytical results during and after bio- and phyto-remediation activity.

Thanks for your attention!