DNA of crayfish spermatozoa as a target of waterborne pesticides - An ex vivo approach as a tool to short-term spermiotoxicity screening.

The spermiotoxic properties of aquatic contaminants might be the cause of low fertilization rate and decreased prolificacy, affecting the success of the impacted populations. The genotoxic potential of pesticides in spermatozoa as an undesirable effect on non-target organisms, namely aquatic invertebrates with external fertilization, emerges as a key question in ecogenotoxicological research. Thus, this study aimed to clarify if DNA integrity of red swamp crayfish (Procambarus clarkii) spermatozoa is affected by waterborne pesticides at environmentally relevant concentrations. By adopting an ex vivo approach, six pesticides were addressed in a short-term assay: herbicides glyphosate (9 and 90 μg L-1) and penoxsulam (2.3 and 23 μg L-1); insecticides dimethoate (2.4 and 24 μg L-1) and imidacloprid (13.1 and 131 μg L-1); fungicides pyrimethanil (2.2 and 22 μg L-1) and imazalil (16 and 160 μg L-1). Genotoxicity was observed in higher concentrations of glyphosate, penoxsulam, dimethoate, pyrimethanil, and imazalil. Imidacloprid was the only pesticide that did not cause non-specific DNA damage, although displaying pro-oxidant properties. Overall, the present study demonstrated the suitability of the ex vivo approach on spermiotoxicity screening, highlighting the potential ecological impact of pesticides on non-target species, such as P. clarkii, compromising sperm DNA integrity and, subsequently, the population success.