Effects and bioaccumulation of Cr(III), Cr(VI) and their mixture in the freshwater mussel Corbicula fluminea.

Chromium has two main oxidation states, Cr(III) and Cr(VI), that can occur simultaneously in natural waters. Current consensus holds that Cr(VI) is of high ecotoxicological concern, but regards Cr(III) as poorly bioavailable and relatively non-toxic. In this work, the effects and bioaccumulation of Cr(III), Cr(VI) and their mixture were studied using the freshwater clam Corbicula fluminea as a model organism.

Toxicity mechanisms of ZnO UV-filters used in sunscreens toward the model cyanobacteria Synechococcus elongatus PCC 7942.

Zinc oxide (ZnO) nanoparticles are commonly used in sunscreens for their UV-filtering properties. Their growing use can lead to their release into ecosystems, raising question about their toxicity. Effects of these engineered nanomaterials (ENMs) on cyanobacteria, which are important primary producers involved in many biogeochemical cycles, are unknown.

Chromium hazard and risk assessment: New insights from a detailed speciation study in a standard test medium.

Despite the consensus about the importance of chemical speciation in controlling the bioavailability and ecotoxicity of trace elements, detailed speciation studies during laboratory ecotoxicity testing remain scarce, contributing to uncertainty when extrapolating laboratory findings to real field situations in risk assessment. We characterized the speciation and ecotoxicological effects of chromium (Cr and Cr ) in the International Organization for Standardization (ISO) medium for algal ecotoxicity testing. Total and dissolved (< 0.

Integrated multi-biomarker responses in two dreissenid species following metal and thermal cross-stress.

With current global changes, the combination of several stressors such as temperature and contaminants may impact species distribution and ecosystem functioning. In this study, we evaluated the combined impact of two metals (Ni and Cr) with a thermal stress (from 12 to 17 °C) on biomarker responses in two bivalves, Dreissena rostriformis bugensis and Dreissena polymorpha. Biomarkers are informative tools to evaluate exposure and effects of stressors on organisms.

Single and combined effects of cadmium and arsenate in Gammarus pulex (Crustacea, Amphipoda): understanding the links between physiological and behavioural responses.

This study aimed at investigating the individual and interactive effects of cadmium (Cd) and arsenate (AsV) in Gammarus pulex (Crustacea, Amphipoda) through the use of several biomarkers. Individuals were exposed for 240 h to two concentrations of AsV or Cd alone, and all the possible binary mixtures of these concentrations of AsV and Cd in a complete factorial design. The pattern of the biomarkers' responses to Cd and AsV alone or in mixture was similar in Gammarus pulex, even if the response intensity varied depending on the tested conditions.

Impaired leaf litter processing in acidified streams : learning from microbial enzyme activities.

Anthropogenic acidification in headwater streams is known to affect microbial assemblages involved in leaf litter breakdown. Far less is known about its potential effects on microbial enzyme activities. To assess the effects of acidification on microbial activities associated with decaying leaves, a 70-day litter bag experiment was conducted in headwater streams at six sites across an acidification gradient.

Behavioural and physiological responses of Gammarus pulex exposed to cadmium and arsenate at three temperatures: individual and combined effects.

This study aimed at investigating both the individual and combined effects of cadmium (Cd) and arsenate (AsV) on the physiology and behaviour of the Crustacean Gammarus pulex at three temperatures (5, 10 and 15 °C). G. pulex was exposed during 96 h to (i) two [Cd] alone, (ii) two [AsV] alone, and (iii) four combinations of [Cd] and [AsV] to obtain a complete factorial plane.

Antagonistic toxicity of arsenate and cadmium in a freshwater amphipod (Gammarus pulex).

Because toxicants rarely occur alone in the environment, a major challenge in risk assessment is to address the combined effects of chemicals on aquatic organisms. This work is aimed at investigating the joint toxicity action of binary mixtures of cadmium and arsenate on Gammarus pulex. Individuals were exposed during 240 h to four single arsenate or cadmium concentrations and binary mixtures of these metals according to a complete factorial plane.

Comparison of arsenate and cadmium toxicity in a freshwater amphipod (Gammarus pulex).

Cadmium is largely documented on freshwater organisms while arsenic, especially arsenate, is rarely studied. The kinetic of the LC50s values for both metals was realized on Gammarus pulex. Physiological [i.

Effect of gender on physiological and behavioural responses of Gammarus roeseli (Crustacea Amphipoda) to salinity and temperature.

The importance of potentially interacting factors in organisms responses to a stress are often ignored or underestimated in ecotoxicology. In laboratory experiments we investigated how gender, temperature and age influence the behaviour and the physiology of the freshwater amphipod Gammarus roeseli under salinity stress. Our results revealed a significant higher sensitivity of females in survival, ventilation and ionoregulation whereas no inter-age differences were reported.