Methyl and propyl paraben impact the physiology of daphnids

With the eminent threat of pollution rising as a result of human actions, many pollutants highlighted as emerging contaminants are appearing in the environment. Parabens are preservatives which are more frequently found to be present in food preservatives and personal care products. These compounds are frequently detected in freshwater ecosystems at concentrations ranging from ng/L to mg/L, and as such they are recognized as emerging contaminants posing ecological risks. In this study, we investigated the effects of methyl and propyl parabens, individually and in combination, on the physiology of daphnids. Using mortality and ingestion rate as phenotypic endpoints and key enzyme activities, we identified different responses to parabens. Feeding rate is crucial for the assessment of environmental impacts as it directly influences growth, reproduction, and survival in aquatic populations. Our findings showed that environmentally relevant concentrations of parabens have significant impacts on the ingestion rate of daphnids, potentially impairing population dynamics. Additionally, assays revealed complex biochemical responses to parabens and dose-dependent alterations in enzyme activity. These results suggest that exposure to parabens impacts the physiology of daphnids through distinct and potentially long-lasting mechanisms. We highlighted the need for further investigation into the effects of mixture of parabens in freshwater ecosystems, providing insights into their ecological risks.