Heavy metals bioaccumulation in water and some organs of <i>Oreochromis niloticus</i> of Wasai Reservoir, Kano State Nigeria

Abstract

Heavy metals contamination of water and food sources in the urban centers poses a threat to public health concerned. Efforts need to be concerted to tackle the menace. One such strategy is to identify the levels of heavy metals contamination of the food sources so as to provide lasting solution to the problem. This research was conducted to assess the levels of heavy metals bioaccumulation in water and Oreochromis niloticus in Wasai Reservoir, Kano State. Four different locations were mapped out as sampling stations. Heavy metals concentration in water of Wasai Reservoir was analyzed as well as their bioaccumulation in gills, and muscles of O. niloticus. The experiment was arranged in Completely Randomized Design with three replications. The data obtained were analyzed using Analysis of Variance with Tuckey’s Test used to separate significant means. The result for the level of heavy metals in surface water of Wasai Reservoir revealed significant difference (P<0.05) in the levels of heavy metals in different locations with months. The result also showed that the levels of heavy metals were higher in station 1 due to high discharge from anthropogenic activities carried out in the area. More so, the levels of heavy metals bioaccumulation in gills and muscles of Oreochromis niloticus are above tolerable limits. The trend in the heavy metal’s bioaccumulation in the tissues and organs of the fish species followed the following order: Cr˃Pb˃Cd with their accumulation in gills above tolerable limits (Cr 0.26 mg/l, Pb 0.12 mg/l, Cd 0.35 mg/l). Thus, the gills of the fish species obtained from Wasai Reservoir especially during the dry season of the year should be discarded and not be consumed by the populace.