Single and combined effects of insecticides on multi-level biomarkers in the non-target amphipod Gammarus fossarum exposed to environmentally realistic levels

This study aims at assessing the effects of two current-use insecticides, imidacloprid and chlorpyrifos, on Gammarus fossarum using multi-level biomarkers. In microcosms, gammarids were exposed for 72 h to insecticides tested individually or in mixture at 0.01, 0.1 and 1 µg/L of each chemical. Multi-metric responses were assessed at the individual level (behavioural traits: locomotion, respiration and amplexus formation) and the cellular level (enzymes involved in growth, moulting, digestion and cell stress). The results showed insecticide-elicited behavioural and biochemical responses from the lowest concentration of 0.01 µg/L. Overall, single exposures stimulated behavioural traits and inhibited enzymatic activities, highlighting subtle impacts at different organizational levels but these were not dose related. For binary mixtures, antagonistic effects (i.e. less-than-additive) on biomarkers were mainly observed when compared with single exposures. Multi-variable analyses indicated the complementarity of behavioural and biochemical biomarkers in identifying sublethal biological alterations and dose-dependent multiple action sites of insecticides. Besides, the mortality observed only for the mixture at 1 µg/L demonstrated a high lethal potential of insecticides in a simple binary combination. To conclude, this study demonstrates disturbances in individual performances and cellular impairments occurring at environmentally realistic exposure levels in a non-target w...
Source: Aquatic Toxicology - Category: Toxicology Source Type: research