ABACUS: Evaluation of availability to biota for organic compounds ubiquitous in soils and sediments

• Research unit: EU RFP
• Project number: 01.0088

Key words (English)

Environmental Protection; Waste Management

Alternative project number (English)

EU project number: EVK1-CT-2001-00101

Research programs (English)

EU-programme: 5. Frame Research Programme - 1.4a.1 Sustainable management and quality of water

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
EPF Lausanne
Institut des Sciences et Techn. de l'Environm., ISTE
Laboratoire de Pédologie, LPE

Abstract (English)

Short summary:

Contamination of soils and sediments by organic chemicals is a major threat to the environmental quality of freshwater and groundwater resources. At present, assessment of the risks of soil and sediment contamination is based on the assumption of bulk organic carbon-based equilibrium partitioning. However, it is generally accepted in scientific circles that this assumption is inappropriate and can lead to an overestimation of the risks of soil and sediment contamination. This project will investigate the mechanistic basis for the formation of different sorbed fractions of contaminants in soils and sediments and the bio-availability of these fractions. Methods will be developed to easily determine bio-available fractions of contaminants in relation to their sorption kinetics. These results will be exploited to develop protocols for the risk assessment of sorbed contaminants in soils and sediments.

Scientific objectives and approach:

The overall aim of the project is to provide methods to determine the actual bioavailable con-centrations of chemicals in soil and sediment in such a way that they may be compared to quality criteria for soil, sediment and water as part of a site-specific assessment of the risks for aquatic systems. The mechanistic basis of the formation of fast and slow sorbing fractions of contaminants in relationship to the role of fractions of particulate and dissolved organic matter will be investigated. The structural characteristics of natural organic matter and con-taminants that are important for sorption will be determined, in part using new computational chemical methods such as molecular modelling. New techniques such as the Tenax method will be further developed to quantify desorption rates from fast and slow sorbing fractions. Desorption rates will be related to the uptake by organisms and biodegradation of fractions of sorbed contaminants. Structure-activity relationships and kinetic models will be developed relating the kinetics of these processes to properties of sediment organic matter and contaminants.
The results of experimental work and modelling will be applied to develop protocols for the measurement of bioavailable contaminant concentrations in contaminated soils and sediments. Methods will be proposed for risk assessments in which the assessment is based on the actual bioavailability of the contaminants. A workshop will be organised in the final phase of this project to disseminate and discuss the proposed protocols under governmental and industrial policy makers.

Problems to be solved:

Soil and sediment contamination remains a major problem in Europe, with an estimated more than 300,000 contaminated sites requiring remediation in Europe. Many of these sites are potential threats to fresh- and groundwater resources. In order to protect these resources, the limited resources available be employed in a cost-efficient manner to clean up sites of polluted soil and sediment. Current environmental policy is based on the assumption of bulk organic carbon based equilibrium partitioning to derive quality standards for soil and sediment. However, it has become apparent over the last few years that this can lead to both enormously overestimated risks from organic contaminants as well as poor predictions of the potential for bioremediation of such sites. Clearly, there is a need for methods to measure the bioavailablity of contaminants in soils and sediments and risk assessment procedures in which the true bioavailability is taken into account in order to enable realistic priorities to be set for clean up of contaminated sites.

Expected Impacts:

The project will provide tools for decision making concerning the dangers of soil and sediment contamination for the quality of freshwater and groundwater resources. Controlling authorities will benefit from the risk assessment methods and harmonisation measures pro-posed. Analytical protocols will become available to help to evaluate risks due to the presence of chemical contamination in soils and sediments. Such protocols may be used in the monitoring of contaminated soils and sediments all over Europe.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 01.0088