Climate change and emerging chemical contaminants in marine organisms: Bioaccumulation, ecotoxicology and public health impacts

Abstract

Chemical contamination and climate change constitute two of the greatest environmental problems related with the increase of anthropogenic activities. Despite both factors acting alone can have negative effects at different levels of biological organization, as well as in seafood safety, the underlying interactions between them are still poorly understood. In this context, this PhD thesis aimed to assess the combined effects of seawater warming and/or acidification on the bioaccumulation of different emerging chemical contaminants (ECCs; MeHg, iAs, DCF, VFX, TCS, Decs, TBBPA, PFOS e PFOA) and ecotoxicological responses of two marine taxonomic groups (fish and bivalves). Overall, warming promoted the bioaccumulation of lipophilic and persistent ECCs (e.g. MeHg, Decs and TBBPA), suggesting increased risks of human exposure to these compounds through the consumption of contaminated seafood in tomorrow’s ocean. Conversely, warming and/or acidification elicited lower bioaccumulation of ionisable and/or less persistent compounds (e.g. iAs, VFX and TCS). Yet, this trend may not necessarily represent lower human risks, as it may be associated with enhanced biotransformation of parental ECCs, potentially representing increased levels of metabolites for which the toxicological attributes (to both biota and humans) are still unknown. Regarding the ecotoxicological effects, overall, the simultaneous exposure to ECCs, warming and acidification promoted more severe responses (at the biochemical, animal condition and behavioural levels) than the ones elicited when each stressor acted in isolation. Such results reveal that the exposure to ECCs in a climate change context will likely defy the resilience of marine organisms, particularly those inhabiting coastal areas. Hence, climate change will greatly challenge the sustainability and management of fisheries and aquaculture resources, thus, calling for urgent regulatory, mitigation and/or adaptive actions at a global scale.