Concentrations and Risk Evaluation of Selected Heavy Metals in Water and African Catfish Clarias gariepinus in River Kaduna, Nigeria

Abstract

Freshwater is a vital medium by which fish for human consumption are cultured, thus, preserving its quality is essential. The presence and bioaccumulation pattern of some heavy metal concentrations in wild African Catfish, Clarias gariepinus (Burchell, 1822) muscles and water samples, collected from River Kaduna during the dry season month of December was assessed, to determine their concentrations, physico-chemical parameters, and risk evaluation of selected metals and their effects on fish quality. Analysis was carried out using standard analytical procedures and methods. Risk assessment for Fe, Pb, Ni, Cd, and Hg were based on average daily dose, hazard quotient, and cancer risk was also determined. Result showed that physico-chemical parameters, were within WHO recommended threshold limits, and mean concentrations of heavy metals followed the order Fe>Pb>Hg>Ni>Cd. Carcinogenic risk ( ) via ingestion of fish muscles for Pb, Hg and Cd were higher than the acceptable limit (10 -6 ). Anthropogenic activities, especially indiscriminate waste disposal were suggested as the main contributor to environmental pollution. Findings reveals possible health implications, thus constant surveillance was suggested to guide appropriate response.

Heavy Metals Health Risk Index (HRI) in Human Consumption of Whole Fish and Water from Some Selected Dams in Katsina State Nigeria

“…The concentration values of Fe for sampled water in this study is lower than that reported for studies conducted in Bayelsa state, Nigeria [29] and Egypt [30] but similar to that of a study conducted in Kaduna state Nigeria [31]. Likewise, the concentration of Pb in the sampled waters is lower than that reported for studies conducted in Ibadan, Oyo state Nigeria [32], Koko creek Bayelsa state, Nigeria [29], lake Baringo Kenya [33] and river Kaduna, Kaduna state Nigeria [31]. Zinc is an essential trace metal for both plants and animals.…”

“…In man, Cd poisoning could lead to anemia, renal damage, bone disorders and cancer of the lungs [38]. The mean Cadmium concentration range for the C. gariepinus samples from the selected dams was 0.0130-0.0138 μg / g which is lower than that reported for C. gariepinus fish from Koko creek, Bayelsa state Nigeria, lake Baringo Kenya and C. gariepinus from Cirato dam west Java Indonesia [29,33,35] but similar to result reported for C. gariepinus analysed from river Kaduna [31], the levels were also low in comparison to the 0.58-1.26mg/100g recorded in fishes of Olomoro water body, [Idodo-Umeh, 2002 University of Ibadan unpublished PhD thesis). Okoronkwo (University of Ibadan unpublished MSc thesis, 1992] also recorded 0.270mg/100g for fishes of the River Niger.…”