Investigation of the relationship between heavy metals (Lead, Nickel, Cadmium) bioaccumulation and levels of catalase and superoxide dismutase enzymes in the tissue of rocky oyster (Saccostrea cucullata) of the Oman Sea

Abstract

Introduction: The body's antioxidant defense system acts as a neutralizer of the effect of reactive oxygen species (ROS) produced under adverse conditions. The aim of this study was to investigate the bioaccumulation of heavy metals in sediment and soft tissue of Saccostrea cucullata and to measure the levels of catalase and superoxide dismutase enzymes as biomarkers of heavy metal pollutants in the Oman Sea coasts.
Materials & Methods: 180 rocky oysters and 18 sediment samples were collected from 6 stations on the shores of the Oman Sea and transferred to the laboratory. The total length and weight of the samples were measured and the soft tissue of the oyster was separated. The concentration of heavy metals was measured using an atomic absorption spectrometer and the level of enzymes was
measured by an enzyme assay kit.
Results: The mean concentrations of cadmium, nickel and lead in rocky oyster soft tissue were 14.9±4.04, 3.9±1.62 and 6.75±2.01, respectively, and in sediment 2.63±0.81, 19.8±2.8 and 22.95±7.77 micrograms per gram of dry weight. Mean levels of catalase and superoxide dismutase were recorded 11.44±4.88 and 22.07±7.94 nmol/min/mg protein, respectively. The pattern of heavy metal accumulation in soft tissue and sediment was Ni<Pb<Cd and Cd< Ni<Pb respectively. The study of the relationship between enzyme levels and metal concentrations showed that increasing the bioaccumulation of heavy metals increases the level of enzymes. So that Ramin station, enzymes showed the highest levels.
Conclusion: The concentration of heavy metals in sediment was higher than the soft tissue of rocky oysters. However, compression of heavy metals concentration in the sediment with the sediment quality standards showed that the amount of metals studied in the sediments of the study area does not threat to organisms in this area.