Effects of cement flue dusts from a Nigerian cement plant on air, water and planktonic quality.

Effects of cement flue dust from Ewekoro cement Kilns were monitored at some aquatic receptor locations. High levels of total suspended particulates (TSPs) and atmospheric deposition rates (ADRs) were recorded within the factory compared to ancillary locations outside the factory. The TSP and ADR levels which were location dependent were significantly higher (P < 0.05) during the dry periods than in the wet season. Irrespective of seasonal variations, the key elements in the emissions were Ca(2+) and Fe(2+). The concentrations of Zn(2+), Mn(2+) and Pb(+) which were trace elements were significantly higher (P < 0.05) in the deposited than in the airborne particulates. The planktonic flora and fauna of the river systems draining the area were poor with 16 phytoplanktonic and nine zooplanktonic species. Numerically, the phytoplanktons were dominated by diatoms (Bacillariophyta) with Synedra sp. being the most abundant species. The zooplanktonic fauna dominated by rotifers had Lecane curvicornis as a regular occurrence in all the three catchment rivers. The physicochemical parameters assayed were significantly higher (P < 0.05) in the factory effluent discharges than in water samples from each of the catchment rivers. Seasonal variations inclusive, HCO(-)(3), CO(2-)(3), Ca(2+) and Mg(2+) constituted the major ionic component of water samples analysed irrespective of location. Alaguntan River which receives effluents directly from the factory had significantly higher levels (P < 0.05) of the assayed ions than the other two rivers draining the cement factory catchment areas.