Chronic effects of diclofenac on a freshwater gastropod, Lymnaea stagnalis

Non-steroidal anti-inflammatory drugs (NSAIDs) are a particularly well-represented drug class in traces of drugs found in surface waters. Among these drugs, diclofenac is one of the most prescribed and consumed NSAIDs with healthy use against pains and symptoms induced by chronic inflammatory diseases. In Europe, concentrations noticed in freshwater range from few ng/L to 15 µg/L for the most important concentration detected. In aquatic ecotoxicology, a lot of studies have been conducted on fish showing an impact of low-ranges concentrations of diclofenac on neurotransmitter, on feeding behaviour, on reproduction and hatching. There is also studies on aquatic invertebrates and most of them were conducted on marine bivalves showing a diclofenac impact on metabolism, fertilization, immunity, embryo development, growth… Compared to study on marine invertebrate and on fish, the impact of diclofenac on freshwater gastropods has been only scarcely explored. The aim of this study is to provide information on chronic effects of environmental concentrations of diclofenac on a freshwater mollusk, Lymnaea stagnalis, with integration of different omics levels. On the first generation exposed, no effect on feeding behavior, locomotion or reproduction were highlighted, but metabolism pathways have been shown impacted. A transcriptomic analysis was also conducted to improve our understanding of molecular mechanism involved in diclofenac effect on non-targeted species. On the second generation exposed, we can see an impact of diclofenac on feeding behavior and reproduction.