Using biomarkers to assess the toxicity of environmental concentrations of heavy metals to the marine gastropod Thais mutabilis

Abstract

This study investigated the effects of environmentally relevant concentration of heavy metals on the antioxidant, metabolic, and detoxifying enzymes activity of marine gastropod Thais mutabilis in Bandar Abbas (north of Persian Gulf). In this study, gastropod samples were collected from five transects in the coastal line, and in each transect, three sampling points were selected. Sampling was conducted in both cold season (autumn 2020) with temperatures of 13–25 °C and warm season (summer 2021) with temperatures of 29 and 40 °C, respectively. Sampled animals had an average weight of 15.38 ± 3.75 and 13.54 ± 4.44 g in cold and warm seasons, respectively. Soft tissues of T. mutabilis were collected and dried using the freeze drier. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to evaluate the concentration of heavy metals (Al, As, Ba, Fe, Pb, Cu, Cr, Cd, Hg, Mn, Ni, Ti, V, Zn). The activity of metallothionein, superoxidase dismutase, and Glutathione S-transferase were examined and possible correlations between heavy metals and enzymes were tested through this study. Results showed that the concentration of heavy metals in the body of T. mutabilis exceeded the values suggested by WHO, FAO, and USEPA. Heavy metals concentration showed the highest values for Fe and Al at transect 1 (cold and warm seasons), As, Ba and Cu at transect four (cold and warm seasons), Ni, Cr and Hg at transect four (warm season). SOD showed the highest activity at transect five in warm and cold seasons at 69.50 ± 9.59 and 64.88 ± 13.92 U/g protein, respectively. Transect three had the greatest values for SOD levels in warm and cold seasons at 41.50 ± 7.58 and 48.01 ± 20.60 U/g protein, respectively. GST demonstrated the largest activity at transect five in warm and cold seasons at 3.76 ± 1.15 U/g protein. MT had the highest levels at transect five in cold and warm seasons at 1.79 ± 0.30 and 1.96 ± 0.29 U/g protein. Oxidative, metabolic and detoxifying enzymes play a leading role as viable biomarkers in assessing the toxicity of hazardous compounds. In this study significant correlations were observed between MT activity and heavy metals (Pb, Al, Ba, Fe, and Zn) as well as SOD and Fe, so T.mutabilis could be a good bioindicator in the polluted marine biota.