Bioaccumulation of Heavy Metals in the Tissues of Periwinkle and Clam from the Mud Flats of Andoni River, Rivers State, Nigeria

Bioaccumulation of heavy metals in periwinkle (Tympanotonus fuscatus) and clam (Senilla senilis) collected from the mud flats of Andoni River was carried out over a six months period. Surface sediment samples were collected with a hand trowel into polythene bags while periwinkle and clam samples were collected by hand picking during low tide, washed thoroughly and transported in an ice-container to the Research Laboratory of the Department of Biology, Ignatius Ajuru University of Education, Port Harcourt for further analysis. Sample preparation followed standard analytical protocols and heavy metal analysis was by Atomic absorption spectroscopy. The concentration of heavy metals (mg/kg) in T. fuscatus was 10.06 ± 0.22, 5.86 ± 0.25, 3.67 ± 0.1, 3.33 ± 0.42 and 0.65 ± 0.09 for Zn>Cr>Ni>Pb>Cd respectively, while that of clam is 6.54±0.51, 6.41±0.15, 4.10±0.6, 2.67±0.1 and 0.39±0.01 respectively for Zn>Cr>Ni>Pb>Cd in descending order of magnitude. All the heavy metals under investigation showed bioaccumulation in the tissues of periwinkle, except cadmium and except cadmium and zinc for clam. Similarly, the concentrations of all heavy metals were above their Rivers State Ministry of Environment and World Health Organization stated limits save for zinc in periwinkle and zinc and cadmium in clam. Thus, indicating that the continued consumption (particularly in large quantities) of periwinkle and clam from the mud flats of Andoni River could lead to far-reaching health implications.