Heavy metal concentrations in whole soft tissues of Anodonta implicate (class: Bivalvia) from Makera industrial discharge point of Kaduna river, Nigeria

Abstract

The whole soft tissues of forty sampled Anodonta implicata of different mean weight range (15.0±0.7-100±0.1 g) from a major industrial discharge point of Kaduna River were analyzed for four heavy metals by use of Atomic Absorption Spectrophotometer. The mean concentrations (ppm) of lead, zinc, copper and cadmium were 0.0494±0.01, 1.5866±0.10, 0.4792±0.24 and 0.0054±0.00, respectively. The differences in tissue weights of the bivalve did not have any significant influence on the concentrations of the different heavy metals (p> 0.05). There was no variation in concentrations of the metals between rainy and dry seasons. The strong positive relationship of the different weight categories of A. implicata is an indication of a similarity in the pattern by which the heavy metals concentrate in the soft tissues. This similarity could be attributed to interactions by the heavy metals in the uptake/accumulation through synergic and antagonistic actions in the soft tissues of the bivalve. The concentrations of Pb and Cd in the different weight categories of the bivalve can be toxic to the organism even at low concentrations. Human consumption or use of the soft tissues as fish bait could constitute a serious health risk. The persistence of Pb and Cd in the biological system could impair the bivalve from performing its ecological roles and cause negative effects on organisms in the higher trophic levels of the aquatic food chain.

Keywords: heavy metals, Anodonta implicata, Kaduna River.