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Chromium is widely used as a tanning agent and can become a contaminant of concern in aquatic ecosystems receiving discharges from industrial or artisanal tanning activities. In a companion study, we showed that Cr discharged by tanneries was bioavailable to indigenous chironomids with accumulation via sediment ingestion likely to represent the predominant exposure route. However, Cr accumulation by chironomids did not directly reflect the degree of sediment contamination and the potential adverse effects of Cr accumulation on chironomids were not evaluated. In the present study, chironomids were exposed to homogenised, field-collected sediments in the laboratory and to intact sediments in situ using a customized caging system. Chromium concentrations were assessed in sediments, exposed larvae of laboratory-reared Chironomus riparius and overlying waters of in situ cages. Experimental results of Cr bioaccumulation were compared with expected Cr body burden in chironomids calculated using biodynamic modelling. Our data provided strong support to the hypothesis that Cr bioaccumulation in the field is specifically controlled by the deposition of contaminated suspended particulate matter (SPM) containing a pool of Cr readily bioavailable to surface deposit feeders. Considering freshly deposited SPM as an additional route of exposure for surface deposit feeders leads to a good agreement between the modelling and experimental results. Additionally, a Cr body burden of about 77 mu g g(-1) d.w. was identified as a tentative threshold above which effects on the growth of C. riparius may appear. While both laboratory and in situ experiments provide evidence for the availability of Cr in aquatic systemimpacted by tannery wastewaters, standard laboratory exposure conditions may miss additional exposure routes in the field and underestimate possible adverse effects on benthic organisms. (c) 2018 Elsevier B.V. All rights reserved.

An ever-increasing diversity of potentially toxic chemical compounds are being developed and released into the environment as a result of human activities (e.g. agriculture, drugs, and cosmetics). Among these, pesticides have been shown to affect non-targeted wildlife since the 1960s. A range of ecotoxicological tests are used to assess the toxicity of pesticides on various model organisms. However most model organisms are metazoans, while the majority of Eukaryotes are unicellular microorganisms known as protists. Protists are ubiquitous organisms of key functional roles in all ecosystems but are so far little studied with respect to pesticide impact. To fill this gap, we developed a new ecotoxicological test based on Euglypha rotunda, a common soil amoeba, grown in culture flask with Escherichia coli as sole food source. We tested this assay with the herbicide S-metolachlor, which is known to affect cell division in seedling shoots and roots of weeds. Reproducible growth conditions were obtained for E. rotunda. The growth of E. coli was not affected by the herbicide. The growth of E. rotunda was affected by the herbicide in a non-linear way, growth being significantly reduced at ca. 15 μg/L, but not at 150 μg/L. Our results show the potential for using soil protists in ecotoxicology and adds to the growing body of evidence for non-linear impacts of pesticides on non-target organisms. With the acquisition of additional data, the protocol should be suitable for standard ecotoxicological tests.

Gammarids were exposed to sediments from a deposition site located on the Rhône River (France) downstream of a fluoropolymer manufacturing plant. Gammarids accumulated to various extents four long-chain perfluoroalkyl carboxylic acids (PFCAs) from C9 to C13, one sulfonate, perfluorooctane sulfonate (PFOS) and three of its precursors (the perflurooctane sulfonamide (FOSA), the N-methyl perfluorooctane sulfonamidoacetic acid (MeFOSAA), the N-ethyl perfluorooctane sulfonamidoacetic acid (EtFOSAA) and the 6:2 fluorotelomer sulfonic acid (6:2 FTSA). Whatever the compound, the steady state was not achieved after a 3-week exposure; elimination was almost complete after a 3-week depuration period for perfluorononanoic acid (PFNA), PFOS, the three precursors and the 6:2FTSA. However, this was not the case for long-chain PFCAs, whose elimination rates decreased with increasing chain length. PFAS accumulation in gammarids occurred via the trophic and respiratory pathways, in proportions varying with the carbon chain length and the terminal moiety.

Triplicate aqueous leachates of a municipal solid waste incineration bottom ash (MSWIBA) were produced according to a European standardised method. Leachates analysis showed relatively low concentrations (less than 1 mgl 1 ) for four metals (iron, cadmium, lead and copper). No mutagenic activity was revealed after performing the Salmonella/microsome assay with and without microsomal activation. With the Vicia root tip micronucleus assay, a significant increase in micronucleated cells was observed between 3.4% and 100% leachate concentration. Significant and elevated antioxidant stress enzyme activities, e.g., superoxide dismutase (SOD), catalase (CAT), peroxidase (PER) and glutathione reductase (GR), were detected in Vicia root tissues even at the lowest tested leachate concentration (i.e., 0.3%), whereas this was not always the case in leaf tissues, which showed tissue specificity for the tested enzymes. At the lowest concentration (i.e., 0.3%), a higher increase was observed (respectively 197% and 45% compared to the control) for root glutathione reductase and peroxidase activities over those of other enzymes (superoxide dismutase and catalase). Our results suggest that MSWIBA aqueous leachates need to be formally tested with genotoxic sensitive tests before recycling and support the hypothesis that plant genotoxicity is related to the cellular production of reactive oxygen species (ROS). D 2004 Elsevier B.V. All rights reserved.

In four countries (France, Greece, Italy, and Sweden) occurrence in sewage treatment plant (STP) effluents and ecotoxicity of the pharmaceuticals carbamazepine, clofibric acid, and diclofenac were investigated. Bioassays were performed on bacteria, algae, microcrustaceans, and fishes in order to calculate their predicted no-effect concentrations (PNEC) and to perform a first approach of risk characterization. For this aim, risk has been estimated by the predicted environmental concentration/PNEC ratio and the measured environmental concentration/PNEC ratio. First, regarding the PNEC, carbamazepine appears to be the more hazardous compound. Second, even though it is demonstrated that carbamazepine, clofibric acid, and diclofenac have been detected in effluents, only carbamazepine have been detected in all sewage treatment plants with the greatest concentrations. Third, risk quotients greater than unity were calculated only for carbamazepine, suggesting that risk for the water compartment is expected.