Contamination Risk Assessment of Physico-chemical and Heavy Metal Distribution in Water and Sediments of the Choba Section of the New Calabar River, Nigeria

Abstract

This study is aimed at assessing geo-environmental risk of physico-chemical and heavy metal distribution in water and sediments of New Calabar River, Eastern Niger Delta. Seven (7) river sediments and twelve (12) surface water samples were collected for the study. Heavy metals (Mn, Pb, Zn, Fe, Mg, Cd, Cr, and Cu) were tested for in both river sediment and surface water. Heavy metals were analysed in river sediments, so as to determine their Contamination Factor (CF), Pollution Load Index (PLI) and Geo-accumulation Index (IGEO) within the study area. W.H.O. limits were also used in evaluating Pollution Index (P1) of heavy metals in surface water. The Pollution Load Index (PLI) level of river sediments ranged from 5.12-33.26. PLI values <1 was considered unpolluted; all samples analysed showed high pollution levels. Of all the heavy metals, Cu, Mg. Cr and Mn had moderate considerable CF levels, while the others were of low levels. IGEO levels were all <1, indicating low levels. For surface water, Pb and Zn had the worst Pollution Index values, with Pb having P values ranging 10-211. There was considerable contribution of pollutants from human activities into the river. Discharge from municipal storm water into the river, and the continued corrosion of sea vessels abandoned along the river flow path have been established. It is recommended that regulatory bodies responsible for protecting the environment pay adequate attention to this stretch of the river.