New insight into effect of pesticides on aquatic life

Research by an international team of scientists has provided new insight into the effects of pesticides on shrimps and snails. The study considered three pesticides – diazinon, imidacloprid and propiconazole – and their toxicokinetic effect on Gammarus pulex and Gammarus fossarm (both freshwater shrimp) and Lymnae stagnalis (pond snail). Previous research has shown that aquatic invertebrate respond to pollution differently, with a large variation in sensitivity among organisms. Not only do species vary in their sensitivities to a given toxicants, given species can vary greatly in sensitivity across toxicants. The latest study, published in Environmental Science & Technology, studies the biotransformation and distribution of the toxicants as a means of explaining the variation in sensitivity to chemicals. “We produced images of the pesticide distribution within the shrimps and snails to better understand which organs are at risk,” said Dr Roman Ashauler from the University of York’s Environmental Department, previously at Eawag where the research was conducted. “It turns out that for some pesticides the distribution in the body matters a lot, whereas for other pesticides it is the organism’s ability to detoxify.” Ashauler said the study has introduced a systematic way of understanding the differences between species’ reactions to pesticides. [caption id="attachment_38462" align="alignright" width="200"] Imaging the distribution of a pesticide in a freshwater shrimp. Blue and green indicate low concentrations, red and brown indicate high concentrations. Credit:Eawag/Harlan Laboratories[/caption] Diazinon and imidacloprid are both neurotoxic, whose toxicity varies among species. This study showed the shrimp were much more sensitive than the pond snail. “But what makes some species more at risk than others? Is it the differences in the nervous system and the target receptors?” said Dr Anna-Maija Nyman, corresponding author now at the University of Eastern Finland. “We cannot answer these questions before linking the effects first to chemical concentrations in the tissues where the target receptors are present.” “Earlier studies have investigated interspecies variation mainly based on exposure concentrations. We were surprised how much the difference in accumulation in the target tissues could explain the interspecies variation in sensitivity and how little variation is therefore due to the differences in target receptors themselves.” Importance of Toxicokinetics for Interspecies Variation in Sensitivity to Chemicals https://www.youtube.com/watch?v=Lzo4ZgqhmE0