New insight into barium toxicity in the gills of the European clam (Ruditapes decussatus): a focus on redox status, fatty acids profiles, and histological structures
Abstract
Barium (Ba) is a naturally occurring alkaline earth metal, which is mined and used for industrial purposes. Through aquatic discharges resulting from industrial activities, Ba can easily impact common organisms in coastal zones, particularly marine bivalves. The aim of the present study is to assess the potential toxic effects of barium chloride (BaCl2), on fatty acid profiling, redox status, and histopathological aspects of Ruditapes decussatus gills under exposure to a set of concentrations (0, 20, 40, and 80 mg/L), for 5 days. Our results revealed, in BaCl2-treated clams, altered levels of saturated fatty acids, decreased content of monounsaturated fatty acids, and increased levels of polyunsaturated fatty acids. Moreover, alterations in arachidonic acid were observed in the gills of treated specimens, accompanied by significant increases in its precursors: linoleic and α-linolenic acids. Our findings also showed changes in the levels of eicosapentaenoic and docosahexaenoic acids. Our results indicated a bioaccumulation of barium, as evidenced by a significant increase in Ba levels in BaCl2-treated specimens. BaCl2 exposure increased the levels of hydrogen peroxide, lipid hydroperoxide, malondialdehyde and protein carbonyl along with enzymatic (glutathione peroxidase and glutathione s-transferase) and non-enzymatic (reduced glutathione, non-protein thiols, metallothioneins and vitamin c) antioxidant. Moreover, our data showed a decrease in ferric-reducing antioxidant power, superoxide dismutase and catalase. The outcomes of biochemical findings were confirmed by histopathological injuries. Our investigation underscores the significance of fatty acid composition as an early sensitive biomarker for elucidating the toxicity mechanisms of BaCl2 in aquatic bivalves, and highlights the broader implications of BaCl2 contamination in coastal ecosystems, emphasizing the need for monitoring and mitigation strategies. By demonstrating the link between oxidative stress and fatty acid profile disruptions, our findings provide valuable insights into the environmental impact of BaCl2 and underscore the importance of continued research into its effects on marine life.