Metals in fish from the upper Benue River and Lakes Geriyo and Njuwa in Northeastern Nigeria

Metal levels (calcium, magnesium, zinc, iron, lead, copper) were determined in fish collected from Geriyo lake, Njuwa lake and the upper Benue river in north-eastern Nigeria. The fish sampled were Tilapia zilli, Alestes baremose, Alestes nurse, Mormyrus macrophthalmus, Heterotis niloticus, Clairas geripienus, Synodontis ocellifer and Citharinus citharus. Zinc, copper and iron concentrations in the fish from the 2 lakes and river were within acceptable limits of the Food Standards Committee for these metals in food. Lead levels were relatively high. The highest mean concentration of 14.4 mg per kg was 7-fold higher than the Food Standards Committee recommended limit of 2 mg per kg for fish. The high levels of lead were not traceable to industrial activities around the river.