Uptake and physiological effects of the neonicotinoid imidacloprid and its commercial formulation Confidor ® in a widespread freshwater oligochaete.

Uptake and physiological effects of the neonicotinoid imidacloprid and its commercial formulation Confidor® in a widespread freshwater oligochaete. Environ Pollut. 2020 Sep;264:114793 Authors: Contardo-Jara V, Gessner MO Abstract The neonicotinoid imidacloprid (IMI) is one of the most extensively applied neuro-active insecticides worldwide and continues to enter surface waters in many countries despite a recent ban for outdoor use in the EU. Yet little is known about ecotoxicological effects on non-target benthic freshwater species exposed to environmentally relevant concentrations of IMI and its marketed products. The aim of the present study was to narrow this gap by assessing effects of pure IMI and its commercial formulation Confidor® on the aquatic oligochaete Lumbriculus variegatus, a key species in freshwater sediments. To this end, we determined dose-response relationships in 24 h toxicity tests, bioconcentration during 24 h and 5 d of exposure to 0.1, 1 and 10 μg IMI L-1, and physiological stress responses by measuring glutathione S-transferase, glutathione reductase and catalase activity in the same conditions. Maximum neonicotinoid concentrations reported from the field were lethal to L. variegatus within 24 h (LC50 of 65 and 88 μg IMI L-1 in pure form and as active ingredient of Confidor®, respectively). At sub-lethal exposure concentrations, tissue content of IMI significantly increased with exposure time. Th...
Source: Environmental Pollution - Category: Environmental Health Authors: Tags: Environ Pollut Source Type: research