Heavy metal concentrations in the West African clam, Egeria radiata (Lammark, 1804) from McIver market, Warri, Nigeria.

Abstract

Samples of Egeria radiata were purchased from local dealers in McIver mar et, Warri, Nigeria, to investigate the presence and concentrations of some heavy metals in order to ascertain the suitability of the clam for human consumption. Analyses using Atomic Absorption Spectrophotometer (AAS) show that E. radiata accumulated some heavy metals with the following sequence of concentration: Iron> Nic el> Lead> Copper> Arsenic> Manganese> Chromium> Cadmium> Mercury. The variability of heavy metals concentration observed in E. radiata during the period of study was affected by rainfall amount. A negative relationship between changes in rainfall and body weight of clams show that the higher the rainfall the lower the mean dry weight. Individual heavy metal differed significantly (P< 0.05) in concentration. However, heavy metal concentrations did not vary significantly (P> 0.05) by months. Out of the nine heavy metals found in E. radiata tissues, lead and cadmium were higher than the WHO/FAO set limit. E. radiata sold in McIver mar et during this period of study were contaminated with lead and cadmium and therefore not fit for consumption.