Alain Abarnou

A pollution-monitoring pilot study involving contaminant and biomarker measurements in the Seine Estuary, France, using zebra mussels (Dreissena polymorpha).

Zebra mussel (Dreissena polymorpha) is an invasive species that has proliferated in European and North American rivers and lakes during the last century. In this study, D. polymorpha has been used to provide information on contamination levels and biological effects in the Seine Estuary (France). The bivalves accumulated polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) to a high degree with values reaching 800 ng/g dry weight for PCBs (sum of 20 congeners), and 1,000 ng/g dry weight of PAHs (sum of 14 compounds) in the whole body. These values are among the highest reported of PCBs and, to a lesser extent, of PAHs in other contaminated areas in the world. Toxic equivalent quantities of PCBs and PAHs detected in zebra mussels varied from 20 to 40 pg dioxin equivalents/g dry weight for PCBs and up to 120 ng benzo[a]pyrene equivalents/ g dry weight for PAHs, indicating a high potential risk for animals feeding on them. Biological impacts, such as altered condition index, decreased lysosomal stability, and high levels of multixenobiotic resistance (MXR) proteins also were detected in mussels living downstream of Rouen, the main city of the Seine Estuary. Taken together, these results indicate that the Seine Estuary is a heavily polluted area with the potential to cause deleterious health effects in some endogenous living organisms. This study also shows that chemical and biological measurements bring different but complementary results that can help diagnose environmental health.

Validation of an analytical procedure for polychlorinated biphenyls, coplanar polychlorinated biphenyls and polycyclic aromatic hydrocarbons in environmental samples

This work describes an efficient analytical procedure for the analysis of PCBs (polychlorinated biphenyls), coplanar PCBs and PAHs (polycyclic aromatic hydrocarbons) from the same sample. The method includes a solvent extraction followed by a combined purification-separation step on an alumina-silica column. Coplanar PCBs are isolated from the first fraction (PCBs) by a further high-performance liquid chromatography (HPLC) fractionation on a PYE [2-(1-pyrenyl)ethyldimethylsilylated silica gel] column. PCBs are identified and quantified by gas chromatography (GC) with electron-capture detection whereas GC with flame ionization detection or mass spectrometry are used for PAH determinations. This method allows the measurement of these contaminants in biota and sediment at trace levels as low as 1 pg g(-1) for coplanar PCBs with a precision better than 20%.

A model of PCB bioaccumulation in the sea bass food web from the Seine Estuary (eastern English Channel)

A bioaccumulation model was developed to simulate the PCB contamination in the sea bass food web from the Seine Estuary. The model relies upon a contaminant mass balance budget for each biological species. Biological processes determine the extent of bioaccumulation: respiration and feeding rates control the uptake of contaminants whereas excretion, spawning, and growth act on the chemicals removal. A step-by-step modelling approach was followed. A first version was a steady-state model validated for the bioaccumulation processes. In the second version seasonal variation was taken into account, and finally in the third version, the model was coupled with a population dynamics model to describe PCB contamination in each age class.

Correlations between dioxin-like and indicators PCBs: Potential consequences for environmental studies involving fish or sediment

Among the numerous PCB congeners, most of the dioxin-like PCBs (DL-PCBs) need to be characterized by hyphenated techniques. It has been shown in several instances that these congeners are well related to the total PCB content in fish. We examined datasets collected mainly in France, on freshwater and marine fish and sediments. A statistical model linking DL- and indicator PCBs was developed for a dataset composed of freshwater fishes, and proved to predict well DL-PCBs from indicator PCBs in all other fish sets, including marine ones. Type II error rates remained low in almost all fish sets. A similar correlation was observed in sediments. Non-dioxin-like PCBs elicit various adverse effects and represent 95% of the total PCBs. A European guideline for them is needed; the correlation between DL- and indicator PCBs could help develop this standard in the future.

A steady-state model of PCB bioaccumulation in the sea bass (Dicentrarchus labrax) food web from the Seine estuary, France

Polychlorinated biphenyls (PCBs) were measured in six compartments of the sea bass (Dicentrarchus labrax) food web from the Seine estuary. Similar PCB patterns were observed in all samples. The main components possess the −245, 234, −2345 chlorine substitution Contamination increases with the trophic level. The highest concentrations were found in sea bass amounting 300 ng g−1 (d.w.) in the oldest individuals. A six-compartment steady-state food web model is proposed for the food web leading to the sea bass. Several exposure pathways are considered in the description of the accumulation by animals: the ingestion of particulate contaminants associated with either phytoplankton and detritus, and the respiratory uptake of truly dissolved contaminants in the overlaying, water. The application of this model indicates that feeding is the principal route of contamination, especially for PCBs which have more than four chlorine atoms and that feeding preference, phytoplankton lipid fraction, and organic carbon, content of detritus are parameters which mostly determine the bioaccumulation in this food web.

Distribution of Polychlorinated biphenyls in dab (Limanda limanda) from the baie de seine (Eastern Channel)

Abstract Polychlorinated biphenyls (PCBs) were determined in liver, muscle and gonad tissues of dab from the Baie de Seine. Very similar PCB patterns were observed in all samples; the main components possess the −245, −234, −2345 chlorine substitution. Contamination levels varied with the lipid content of the tissues. The highest concentrations were found in liver in the range 100–700 ng g 1 dry weight for the PCB congener No. 153 (22′44′55′ hexachlorobiphenyl). The concentrations in liver and muscle increased with age for both male and female fish. Gonads from male fish showed continued low contamination. However, the contamination in gonads from mature female fish (> 2 years) varied during the year: the highest concentrations were observed in early spring, just before the spawning which is an important pathway for the elimination of these contaminants.