Heavy metal concentration in soft tissues of freshwater clam (Galatea paradoxa Born 1778) from Diebu Creek, Bayelsa State, Nigeria

Abstract

Heavy metal concentration in soft-tissues of freshwater clam (Galatea paradoxa) from Diebu Creek, Bayelsa State, Nigeria, was investigated. Clam samples were obtained from the creek for three consecutive months from February to April 2022 and categorized into three class sizes: big (>50 mm), medium (36 - 50 mm) and small (20-35mm). Samples were analysed for cupper (Cu), lead (Pb), iron (Fe) and zinc (Zn). The results show that the big-size clams (17.37±0.01 mg/kg) had the highest copper concentration and small-size clams the lowest concentration (0.00±0.00 mg/kg). For lead, the big-size clams (1.48±2.52 mg/kg) also recorded the highest concentration and small-size clams (0.32±0.02 mg/kg) the lowest concentration. For iron, the highest concentration was established in big-size clams (21.81±0.17 mg/kg) and lowest concentration in small-size clams (3.55±0.10 mg/kg). In the case of zinc, the highest concentration was likewise noticed in big-size clams (30.00±0.16 mg/kg) and lowest concentration in small-size clams (0.14±0.00 mg/kg). Heavy metal concentration mean values recorded from the different sizes of clams portrayed a significant difference (P<0.05) between the mean values of big-size clams from the medium and small size clams. The concentration level of metals in the clams from Diebu Creek were within the acceptable limits therefore, meets the acceptable standards and are safe for human consumption. Heavy metals generally have relatively high density and are poisonous even at low concentrations therefore should be curtailed to the barest minimum level to reduce seafood contamination in water bodies particularly in Diebu Creek and its environs in Bayelsa State.