The Invasive Blue Crab Callinectes sapidus as a Model for Assessing Sub-Lethal Effects of Polyvinyl Alcohol

Polyvinyl alcohols (PVAs) are synthetic, water-soluble polymers widely used in industrial, medical, and personal care products. Their slow biodegradation raises concerns about potential impacts on marine ecosystems. This study examined how PVA exposure affects the blue crab Callinectes sapidus, an invasive species in the Mediterranean Sea. Crabs were exposed to three PVA concentrations (0.5, 5, and 25 mg L^-1) along with a control group, for periods of 10 and 20 days. Oxidative stress was assessed by measuring antioxidant enzyme activities, including superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GPx), and lipid peroxidation levels in muscle, gill, and hepatopancreas. Cell viability in the hemolymph and hepatopancreas was also evaluated. The results showed that hepatopancreas cells were more sensitive than hemolymph cells. Oxidative stress increased with exposure time and concentration, as indicated by elevated antioxidant enzyme activity and lipid peroxidation. After 10 days, early detoxification responses were observed, while after 20 days of exposure, clear dose- and time-dependent trends were evident, highlighting an intensification of physiological dysfunctions with increasing PVA concentrations and prolonged exposure duration. The histopathological observations showed limited alterations in muscle and hepatopancreas tissue but evident structural changes in gill tissues, particularly after prolonged exposure. The findings reveal a concentration- and time-dependent biological response to PVA, highlighting physiological changes at higher exposure levels and the need for further research on environmental consequences.