Coastal Zones

Biography

Biography: Dr John Paul Unyimadu

Abstract

Polychlorinated Biphenyls (PCBs) are semi-volatile chlorinated hydrocarbons, which are toxic and bio-accumulate in the environment. This research was the first study to report the levels and distribution patterns of PCBs along River Niger, Nigeria. Between 2008-2009, fifteen representative sites along River Niger; three each from Gurara River (tributary) in Niger State, Lokoja (confluence) in Kogi State, Onitsha in Anambra State, Brass and Nicolas Rivers (tributaries) in Bayelsa State, were purposefully selected for sampling over a 24-month period. One hundred and twenty sediment samples (30 per quarter) were collected using Van Veen grab sampler. The sediments were extracted and cleaned up using standard methods. The levels of PCB congeners in the samples were determined using gas chromatograph HP 5890 Series 11 equipped with electron capture detector. The possible ecological risks of the PCB levels in the sediments were assessed using US EPA sediment quality guidelines. The total PCBs (µg/kg) dry weight ranged between 536 to 2964 (µg/kg) dry weight. The US EPA sediment quality guideline, probable effect concentration (PEC) of (676 µg/kg) for PCBs were exceeded in 93.3 % of the samples, sometimes four folds. The highest concentration was detected at the delta region of the River Niger (Nicolas and Brass Rivers) which act as repositories of these contaminants. The level of PCBs in sediments of River Niger presents potential danger for benthic and human health. Therefore, continuous monitoring of this River is very important.