Partition of metallic and organochlorinated pollutants and monoorthosubstituted PCB pattern in the trophic web from different areas of the river Seine

Polychlorinated biphenyls, polybrominated diphenyl ethers, and phthalates in roach from the Seine River basin (France): impact of densely urbanized areas

Endocrine disruptors (EDs) from three chemical classes-polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and phthalates-were investigated in the Seine River and one tributary, the Orge River, upstream and downstream of urban areas. The impact of urban areas was characterized by a concentration increase of all compounds in the Seine River and for phthalates and PBDEs in the Orge River. In the Seine River, from upstream (Marnay) to downstream (Triel) of urban areas, water concentration increases were greater for diethylhexyl phthalate (DEHP) (6 times, p < 0.05) and ∑tri-hexa BDE (5 times [p < 0.05]) than for ∑7PCBi (2.6 times). Simultaneously, sediments displayed a strong accumulation of contaminants downstream and compared with upstream values, their concentrations increased greatly: 202-fold for DEHP, 69-fold for BDE209, 25-fold for ∑tri-hexa-BDE, and 11-fold for ∑7PCBi. Variations of fish ED concentrations gave an indication of their habitat contamination increase observed downstream of densely urbanized areas of the Seine River, especially for PBDEs (∑tri-hexa-PBDEs = 14-fold increase ≤15.7 ± 6.9 ng g(-1) dry weight [dw; p < 0.001]) and for PCBs (∑7PCBi eightfold increase ≤211 ± 55 ng g(-1) dw [p < 0.01]). PCA results highlighted relationships between the different ED classes. A correlation (p < 0.05) was observed between PCB and PBDE fish concentrations, suggesting common sources and similar absorption mechanisms. For PCBs, which were poorly biodegraded, the bioaccumulation factor was strongly correlated (p < 0.001) to molecular hydrophobicity, whereas for PBDEs a negative correlation (p < 0.05) was observed related active debromination processes. This multichemical study investigates for the first time the occurrence of a wide range of EDs in roach, which was chosen as a sentinel species for this survey of surface water contamination.

Differential hepatic metal and metallothionein levels in three Feral fish species along a metal pollution gradient

The accumulation of cadmium, copper and zinc and the induction of metallothioneins (MT) in liver of three freshwater fish species was studied. Gudgeon (Gobio gobio), roach (Rutilus rutilus) and perch (Perca fluviatilis) were captured at 6 sampling sites along a cadmium and zinc gradient and one reference site in a tributary of the Scheldt River in Flanders (Belgium). At each site up to 10 individuals per species were collected and analyzed on their general condition factor (K), hepatosomatic index (HSI) and gonadosomatic index (GSI). From each individual fish the liver was dissected and analyzed on Cd, Cu and Zn and MT-content. Although not all species were present at each site, hepatic Cd and Zn levels generally followed the pollution gradient and highest levels were measured in perch, followed by roach and gudgeon. Nevertheless also an effect of site was observed on this order. MT-levels appeared to be the highest in gudgeon although differences with the other species were not very pronounced and depended on the site. Significant relationships were found between hepatic zinc accumulation and MT levels. For each species the ratio MT(theoretical)/ MT(measured) was calculated, which gives an indication of the relative capacity to induce MTs and thus immobilize the metals. Perch had the lowest capacity in inducing MTs (highest ratio). Relationships between hepatic metal levels and fish condition indices were absent or very weak.

Organochlorine pesticides and polychlorinated biphenyls in sediments and fish from freshwater cultured fish ponds in different agricultural contexts in north-eastern France

Organochlorine pesticides (HCB, HCH with α-, β-, and γ isomers, heptachlor, cis-heptachlor epoxyde, trans-heptachlor epoxyde, endosulfan with α- and β isomers, sulfate endosulfan, o,p'-DDT, p,p'-DDT, o,p'-DDE, p,p'-DDE, o,p'-DDD, p,p'-DDD, chlorothalonil, alachlor, aldrin, dieldrin, methoxychlor, oxychlordane, chlordane with α- and γ isomers, p,p'-dicofol and o,p'-dicofol) and indicators PCBs (IUPAC nos. 28, 52, 101, 118, 138, 153, and 180) were studied both in sediments and muscles of farmed fish species (Cyprinus carpio and Perca fluviatilis). Samples were collected from fish ponds located in the hydrographic basin of the Moselle River (Lorraine Region, France). OCPs and PCBs were present at low concentrations both in sediments and fish muscles. Concerning sediments, ∑DDTs revealed concentrations ranging from 0.2 to 2.30 ng g(-1) dw and ∑PCBs ranged from 0.3 to 3.5 ng g(-1) dw. Concerning fish muscles, the highest concentrations in OCPs were those of p,p'-DDE, with average concentrations of 0.57±0.44 ng g(-1) ww for carp and 0.58±0.29 ng g(-1) ww for perch. The contamination profiles proved to be different depending on the fish species. Indeed, HCH-isomers, HCB, and dieldrin were detected only for the carp and always at low concentrations. For example, the highest concentration of HCHs was observed for β-HCH with a mean value of 0.64±0.15 ng g(-1) ww for carp. As for PCBs, the levels of ∑PCBs ranged from 0.3 to 6.4 ng g(-1) ww in carp muscles and from 0.90 to 5.60 ng g(-1) ww in perch muscles.

Modeling the potential influence of particle deposition on the accumulation of organic contaminants by submerged aquatic vegetation

Submerged aquatic vegetation can act as both a mitigating factor(e.g., reducing downstream impacts of pesticides following runoff/spray drift) and mobilizing factor (e.g., remobilization of contaminants from sediments) influencing the fate and distribution of organic contaminants in the environment. Consequently, there has been wide scientific and regulatory interest in assessing the role of these plants in different contamination scenarios. Mechanistic models describing the environmental fate of contaminants in submerged aquatic vegetation are useful tools for interpreting laboratory and field measurements in addition to providing valuable information to risk assessors. In this study, we developed a fugacity-based model to investigate the influence of particle deposition to plant surfaces on the fate and distribution of two substances in small ponds. The main motivation for conducting this study was to address the fact that the potential contribution of this process is not typically considered by many types of models describing contaminant dynamics in submerged aquatic vegetation. For the hydrophobic substance included in this evaluation (lambda-cyhalothrin), model performance was greatly improved by including this process. The model was also applied in a generic context to compare the importance of particle deposition versus directwater uptake as a function of chemical properties (log Kow) and concentration of suspended solids in the water column. The generic application demonstrated that contaminant mass transfer is dominated by particle deposition for chemicals with log Kow greater than approximately 5.5--6 across a wide range of suspended solid concentrations and can be important even for low log Kow substances in some circumstances. Further empirical and modeling studies are recommended to explore this process more comprehensively.

Seasonal variation of the distribution of PCBs in sediments and biota in a PCB-contaminated estuary

To elucidate the effects of seasonal variation of precipitation on the distribution of polychlorinated biphenyls (PCBs) in estuarine sediments and benthic feeders, PCB concentrations of river surface sediments and mullet fish (Liza macrolepis) were investigated in the estuary of Er-Jen River near former PCB contamination sites before and after each wet season from 2002 to 2004. Analyses of grain size distribution and organic matter revealed that the pre-existing surface sediments were covered by and mixed with the soil particulates brought by surface runoff after each wet season. Obvious increment of PCB content and significantly elevated fraction (p<0.005) of light PCBs of the river mouth's sediments after each wet season indicated that the invading particles were rich in un weathered PCBs. PCBs previously buried in the surface soil of heavily contaminated sites were flushed into this estuary through surface runoff. The precipitation altered the PCB patterns in sediment organic matter, the dietary source of mullet, and consequently changed that of mullets accordingly, which all possessed significant greater fraction of light PCBs. In this study, it was demonstrated that seasonal summer precipitation affected the distribution of PCBs on surface sediments and the mullets of this estuary. PCB residuals retained in this region still pose potential threats to biota resided here.

Concentrations of PCBs, organochlorine pesticides and heavy metals (lead, cadmium, and copper) in fish from the Drôme river: potential effects on otters (Lutra lutra)

In this study samples of ten species of fish were analyzed for concentrations of organochlorine pesticides, PCBs and heavy metals (Pb, Cd, and Cu). Fish were captured using electric fishing on ten sites along the Drôme river (Rhône-Alpes region). Quantitative determination of the organochlorine and PCBs compounds was performed by gas chromatography-electron-capture detection (GC-ECD). The concentrations of heavy metals were determined by atomic absorption spectrophotometry. Samples contained detectable concentrations of lindane, PCBs, and heavy metals but at concentrations below the maximum residue limit (MRL). Non-parametric statistical analysis was performed to distinguish groups of sites with different levels of contamination. PCBs concentrations increased along the river with four groups of sites significantly different from each other. Cadmium concentrations were below the MRL. Lead contamination showed two groups significantly different and a repartition similar to PCBs. Copper contamination was correlated with the localization of vineyards. We assessed the potential effects of contamination the otter (Lutra lutra). The concentrations of all pollutants analyzed in fish sampled in this study are lower than the threshold values described in literature. The Drôme river is relatively unpolluted river, and the establishment of otter populations should not be affected by pollution.

Equilibrium partition theory applied to PCBs in macrophytes

The applicability of the equilibrium partition theory (EPT) for PCB accumulation in submerged macrophyte shoots was investigated using field data. The equilibrium state of PCBs between macrophyte shoots and sediments was verified by testing the direct proportionality (slope = 1 in a log-log relationship) between congener concentrations in the lipids of macrophyte shoots (Cli) and in the organic fraction of sediments (Cso), using the slope-range method. A significant proportionality was found between Cli and Cso (slope of the log-log relationship: 0.978 +/- 0.041; R2 = 0.847; P < 0.001). The biota-sediment accumulation factor (BSAF) predicted from this relationship (3.74, SE: 1.14) was in the 1-4 range that is suggested in the literature. These results indicate that, in our study sites, EPT is applicable to PCBs in macrophyte shoots. This opens interesting perspectives in environmental monitoring.

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.