ABSTRACT

Contamination of aquatic bodies with a vast array of pollutants has seriously increased the worldwide attention. Anthropogenic activities resulting from modern agricultural practices, rapid urbanization and industrialization involve the increased release of various chemical pollutants and toxicants, such as industrial effluents, biocides, pesticides and heavy metals. The aim of this study was to investigate the presence of heavy metals in muscle and kidney of fishes using histological and atomic absorption spectrophotometric techniques. This research study was conducted in Ovia north east and Egor local government areas of Benin City Edo state. Fish kidney and muscle samples were collected from selected fish ponds located in the study area. The samples were processed for the estimation of five heavy metals. The five heavy metals tested for include; lead, mercury, copper chromium and zinc using Atomic Absorption Spectrophotometer. The muscles and kidney tissues were also analyzed histologically. Results were analyzed using SPSS version 21 and then presented in tables. Results of the study showed that Cu, Zn, Cr, Cd, and Pb levels in the Muscles were significantly higher in the muscles than in the Kidney (P<0.05). Comparism of the heavy metal levels in the various locations showed no significant difference (P>0.05). The level of Cu in the muscles and kidney (41.52mg/kg and 15.86mg/kg respectively) exceeded the limit set by FAO and WHO (10mg/kg). Cr concentrations was found to be higher than the FAO/WHO permissible limits of 2.0mg/kg. Other metals analyzed fell within the permissible limits set by WHO/FAO. Sections of the muscle tissues showed normal myocytes and normal histological architecture while that of the kidneys showed histological damages marked by destroyed glomerulus and tubules. In conclusion, the heavy metals and metalloid concentrations in muscle of all fish were within the corresponding standards, except the Cr and Cu concentrations respectively.