ABSTRACT
During a decade (1996-2006), ecotoxicological studies were carried out in biota of the Vaccarès Lagoon (Biosphere Reserve in Rhone Delta, France). A multicontamination was shown at all levels of the trophic web due to a direct bioconcentration of chemical from the medium combined with a food transfer. Here, the pollutants investigated were organochlorines, among which many compounds banned or in the course of prohibition (or restriction) (PCB, lindane, pp'-DDE, dieldrin, aldrin, heptachlor, endosulfan...) and some substances likely still used in the Rhone River basin (diuron, fipronil). The results confirmed the ubiquity of contamination. It proves to be chronic, variable and tends to regress; however contamination levels depend on the trophic compartment. A biomagnification process was showed. A comparison of investigation methods used in other Mediterranean wetlands provides basis of discussion, and demonstrates the urgent need of modelling to assess the ecotoxicological risk in order to improve the management of such protected areas.
Subject(s)
Aquatic Organisms/metabolism , Food Chain , Hydrocarbons, Chlorinated/metabolism , Seawater/chemistry , Water Pollutants, Chemical/metabolism , Aldrin/analysis , Aldrin/metabolism , Animals , Dichlorodiphenyl Dichloroethylene/analysis , Dichlorodiphenyl Dichloroethylene/metabolism , Dieldrin/analysis , Dieldrin/metabolism , Endosulfan/analysis , Endosulfan/metabolism , Environmental Monitoring , France , Heptachlor/analysis , Heptachlor/metabolism , Hexachlorocyclohexane/analysis , Hexachlorocyclohexane/metabolism , Hydrocarbons, Chlorinated/analysis , Polychlorinated Biphenyls/analysis , Polychlorinated Biphenyls/metabolism , Water Pollutants, Chemical/analysis , WetlandsABSTRACT
European eels (Anguilla anguilla), crucian carps (Carassius carassius) and catfish (Ictalurus nebulosus) were collected in three coastal locations of the Vaccarès lagoon (French National Nature Reserve of Camargue). The purpose of this paper is to report results of the first biomonitoring investigation in fish living in this protected coastal wetland. Residues of organochlorine (OC) contaminants (i.e. SigmaPCBs, gammaHCH, HCB, dieldrin, pp'-DDE) were determined in hepatic and muscular tissues, in order to compare geographical and seasonal distribution. Total exposure levels appeared to be more important in fatty fish such as eels than in crucian carps and catfish. The highest OC concentrations in liver (SigmaPCB) and in muscle (gammaHCH) were detected in Spring in some fish coming from a site located near the mouth of a canal draining irrigation waters of rice fields. Morphophysiological parameters (condition factor, organo-somatic indexes and lipid tissue composition) were measured concomitantly. Correlations between the hepatic and muscular burdens of OC and condition factor or organo somatic indexes were infrequent and rather negative. Localization of lipid accumulation (neutral or polar lipids) depended on metabolic rates of different species and appeared related to the fish trophic level.
