Monitoring organic contaminants in small French coastal lagoons : comparison of levels in mussel, passive sampler and sediment

Abstract : In this study, the distribution of organic contaminants was investigated in the particular context of three Mediterranean coastal lagoons, where pollution input was hypothesised to come mainly from sediments resuspension. Mussels and semi-permeable membrane devices (SPMDs) were exposed to the water column for one month and then their content in estrogen-, benzo[a]pyrene- and dioxin-like substances as well as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls and alkylphenols was determined with biological and chemical analyses. PAH concentration was high in sediments (up to 1028 ng g-1 dry weight), however the aqueous PAH concentrations estimated from SPMD data could be considered below the levels inducing adverse effects according to the environmental quality standards proposed by the Water Framework Directive. Dioxin-like activity was observed in sediments but not in mussels and SPMDs. In the two sewage-impacted lagoons, nonylphenols could be quantified in sediments, SPMDs and mussels. Nonylphenol concentrations in mussels were among the highest found in the literature. However, since nonylphenols contributed only to a small part of the estrogenic activities observed, natural or synthetic steroids originating from wastewater discharges could be also implicated in these responses in sediments.