| Abstrakt: |
In the context of the European legislation on chemicals (existing, new chemicals and biocides) a risk assessment for the environment and human health is performed. A technical guidance document (TGD), in support of Commission Directive 93/67/EEC on risk assessment for new notified substances and Commission Regulation (EC) No1488/64 on risk assessment for existing substances has been developed in 1996 and was recently adapted for the marine environment. The methodological concept is based on the relation between a value representing the contamination level of a chemical substance in the environment (exposure assessment) and a value representing its effects on the environment (effects assessment). The exposure value is expressed as PEC for ?Predicted Environmental Concentration? and the effect value is defined as the PNEC, for ?Predictive No effect Concentration?. The risk characterisation is represented by the value of the PEC/PNEC?ratio. The recent adaptation of the technical guidance document lead to two different aquatic assessments: one for the inland compartment and one for the marine compartment. This adaptation was conducted during two years and is the result of the co-operation of the European Commission and the OSPAR Convention. The main adaptations of the document to the marine environment concern the dilution rate in the water compartment, the behaviour of the substances, biodegradation, the local and regional exposure assessment scenario, effects assessment and secondary poisoning. A specific part dealing with PBT substances (Persistent, Bioaccumulable and Toxic) was also added. The initial concept of the guidance was however the same as for the inland environment. The document was used in the context of a specific study in France: ?Environmental risk assessment of chemical releases of nuclear installations in Nord-Cotentin, France?. The chemical releases of industrial sites were mainly composed of metals and a few organic chemicals. The releases of 27?substances in the marine environment were assessed. Limits and uncertainties of the methodology were underlined regarding, in particular, the determination of PNEC and the lack of ecotoxicological data for the marine environment. La l?gislation europ?enne sur les produits chimiques (substances existantes, substances nouvelles, biocides) impose une ?valuation du risque chimique afin d'assurer la protection de la sant? humaine et celle de l'environnement. Un document guide m?thodologique europ?en, appel? "Technical Guidance Document" (TGD) a ?t? ?labor? en 1996 pour permettre la mise en ?uvre d'une telle proc?dure qui soit commune ? l'ensemble des ?tats membres de l'Union europ?enne. Le concept m?thodologique utilis? consiste ? mettre en relation l'?valuation de la contamination du milieu, exprim?e en concentration pr?visible, baptis?e PEC ("Predicted Environmental Concentration") et l'?valuation des effets, exprim?e en terme de concentration pr?visible sans effets, baptis?e PNEC ("Predicted No-Effect Concentration"). La caract?risation du risque est bas?e sur la valeur du rapport PEC/PNEC. La r?vision du document guide europ?en a conduit ? scinder la proc?dure d'?valuation du risque environnemental dans les milieux aquatiques en deux chapitres distincts, l'un concernant le milieu continental, le second sp?cifiquement le milieu marin. Ce travail d'adaptation du TGD au milieu marin a ?t? men? durant deux ans dans le cadre d'une collaboration entre la Commission europ?enne et la Convention OSPAR. La premi?re version de ce document constitue un document de r?f?rence pour l'?valuation du risque chimique en milieu marin. Sans remettre en question le concept m?thodologique de base, les modifications apport?es pour adapter le TGD au milieu marin concernent?: le comportement des substances, la biod?gradation, l'?valuation de l'exposition et les sc?narios d'?mission envisag?s ? l'?chelle locale et r?gionale, l'?valuation des effets, l'?valuation de l'empoisonnement secondaire chez les pr?dateurs via le transfert trophique et la protection du milieu marin vis-?-vis des substances PBT (persistantes, bioaccumulables et toxiques). Dans le cadre de l'?valuation des risques environnementaux des rejets chimiques des installations nucl?aires du Nord-Cotentin, cette m?thodologie a ?t? utilis?e sur 27?substances parmi lesquelles quelques organiques et un grand nombre de m?taux. Les premiers r?sultats de cette ?tude mettent en ?vidence les limites et les incertitudes de la m?thode notamment dans la d?termination des PNEC en milieu marin o? les donn?es ?cotoxicologiques sont faibles. |
