Biochemical effects of bifenthrin on chironomids larvae under field and laboratory conditions

BALLESTEROS, M.L; LONG, S.; KELLAR, C.; MIGLIORANZA, K.S.B.; BISTONI, M.A; PETTIGROVE, V.

Berlin

Congreso; 6th SETAC World Congress / SETAC Europe 22nd Annual Meeting; 2012

Bifenthrin is a third generation synthetic pyrethroid pesticide that is widely used in Australia and is frequently found in freshwater sediments in relatively low concentrations. However, it is highly toxic to non-target species such as native chironomid larvae. Our main goal was to compare the effects of bifenthrin on chironomid larvae under different exposure conditions. Chironomus tepperi larvae (5 days old) were exposed to sub-lethal sediment concentrations of bifenthrin for 5 days. A field microcosms exposure with bifenthrin-spiked sediments (using the same concentrations as the laboratory exposure) was carried out for 50 days to allow for colonization and development of chironomid larvae. At the end of both experiments, larvae were collected and glutathione-s-transferase, glutathione reductase and glutathione peroxidase were measured. Field based microcosms were also conducted to evaluate the impact of sediments spiked with bifenthrin on macroinvertebrate assemblages. No significant effects were detected on survival or enzyme activity in C. tepperi larvae following laboratory exposure. Results provide evidence that short-term exposures to sublethal concentrations of bifenthrin did not cause significant effects of C.tepperi larvae. The microcosm method showed also to be a valuable tool in the risk assessment of contaminants and effects of pollutants on aquatic invertebrates.