Some Metal Elements Concentration in <i>Malletia cumingii</i> (Hanley, 1860) (Bivalvia) in Okpon River, Cross River State, Nigeria

Abstract

Molluscs are important food item all over the globe. They have been harvested from the wild and some cultured for food; such that 20% of aquatic animal protein comes from molluscs. They have also been widely used as indicator of pollution. On the other hand, many are intermediate hosts of parasitic disease of many animals and man. Malletia cumingii is usually harvested in Okpon River, a tributary of Cross River in Cross River State of Nigeria. Because of the value of Molluscs as indicator of pollution, this species was analyzed to ascertain the metal elements concentration levels for reason that some of these metals are toxic to man. Samples were collected from three locations along the River. Sampling was done two times to include the two main seasons of the year (dry and wet seasons). The samples were oven-dried (MAMMART) at 100°C and were pounded in mortar to powder form. Metal concentrations were measured using flame photometer (RP 7) and atomic absorption spectro-photometer. Metals analyzed included Copper, Cadmium, Chromium, Iron, Manganese, Nickel, Lead, Zinc, Calcium and Magnesium at different wavelengths. Results showed that metal concentration was increasing from the upper reaches of the river downward except zinc. It was suggested that zinc have a point source in the upper reaches while others metals were added to the water body by anthropogenic activities. However, the concentration of the metals did not reach toxic level in the molluscs for human consumption.