DETERMINATION OF HEAVY METALS IN CRAYFISH SOLD IN SELECTED TOWNS (Asaba, Ozoro, Patani and Sapele), DELTA STATE NIGERIA

Igbuku, A.U.

Department of Science Laboratory Technology

Delta State Polytechnic, Ozoro.

Email; Igbukuaugustinaufuoma@gmail.com

Abstract: Anthropogenic inputs of pollutants such as heavy metals into the marine environment have increased their levels to large extents within the past few decades. This study investigated the level of heavy metals in crayfish sold in selected towns (Asaba, Ozoro, Patani and Sapele) Delta State Nigeria. Crayfish samples were purchased from the local markets and digested using nitric acid/hydrochloric acid mixture. Heavy metal concentration was determined using Atomic Absorption Spectrophotometer (Buck 200). The result obtained ranged from 0.161 – 4.466mg/kg for Fe; 2.666 – 5.050mg/kg for Co; 0.074 – 0.517mg/kg for Cr; 0.235 – 0.758mg/kg for Mn and 0.513 – 4.875. Chromium was the most dominant metal while cadmium was the least occurring metal. The mean concentration of the metals follows in the order: Cr>Zn>Pb>Fe>Cu>Mn>Ni>Cd. The result revealed that Cr, Ni, Co and Pb exceeded the guideline safe limits by WHO/IAEA. The level of Cr, Ni, Co and Pb in this study calls for concern considering the toxic nature of the metals. There is thus the need to regularly monitor the prevalence of heavy metals in crayfish sold in the region.