The concentrations of some ferruginous ore associated heavy metals were determined in freshwater from River Niger. Water samples were collected from both upstream and downstream along the mainstream drainage channel, traversing past the steel production industry Ajaokuta between 2003 and 2005. The water samples were digested according to standard methods and tested for Cadmium (Cd), Manganese (Mn), Chromium (Cr), Nickel (Ni), Cupper (Cu), Zinc (Zn) and Lead (Pb) using Unicam 969 atomic absorption spectrophotometer. The mean concentrations (mg/L) of heavy metals were: Mn, 3.85 ± 0.93; Zn, 2.72 ± 0.57; Cu, 2.17 ± 0.73; Cr, 2.08 ± 1.27; Ni, 0.78 ± 0.12; Cd, 0.05 ± 0.02; Pb, 0.03 ± 0.02. The concentration of Mn, 1.74 to 8.37 mg/L; Cu, 0.58 to 4.50 mg/L; Cd, 0.02 to 0.13 mg/L were variable and inundating. The variations in heavy metal levels between sampling stations were not significant (P > 0.05) with relative standard deviation from 2% for Cd and Pb to 12.7% for Cr. The order of dispersion (2 to 14%) showed that the measured metals are nearly homogenously distributed in the water with Cr, Mn, Cu and Zn having the highest concentration variations in the water samples. The concentrations of the evaluated heavy metals were within the guideline levels for freshwaters, and did not appear to have significant negative impact on the water quality.

This study investigated levels and distribution pattern of chlorinated organic compounds (COCs) otherwise known as organochlorine pesticides in sediment samples at downstream of Aiba watercourse in Iwo, South-western Nigeria. Soxhlet extraction method followed by GC–ECD analysis were used to ascertain levels of COCs in the sediment samples collected from four different locations along the stream. Eighteen COCs were detected with trans permethrin and endosulfan sulfate having highest and lowest concentrations of 375.70 ± 689.41 and 0.03 ± 0.05 µg/g, respectively. The varying levels of COCs as obtained in this study were attributed to organochlorine pesticides contamination emanated from different agricultural practices and domestic sewage loads of the study area.

-(<0.01-2.8 mg/l) and SO 4 2-(0.6 -4.7 mg/l). The concentrations of anions and major cations in most of the investigated boreholes were found to be chemically conformable with WHO standard for safe water. However, most of the trace elements with exception of Cr and Co were found to be significantly higher than the WHO standards for safe water.