ECOLOGICAL AND HUMAN HEALTH RISKS ASSOCIATED WITH SOIL POLLUTION BY PAHS AND HEAVY METALS IN THE NIGER DELTA

Abstract

Despite the prevalence of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) in Niger Delta's crude oil regions, comprehensive research on their concentrations and combined risks in crude oil-contaminated soils is lacking. Our study focused on examining the concentration, source, spatial distribution, and health risk of 16 PAHs and 9different HMs in soils across a gradient of Niger Delta area Nigeria. The objective was to gain a comprehensive understanding of the HMs and PAHs' behavior in the environment and their potential impact on human health. The mean total concentrations of 16 PAHs (Σ16PAHs) were 779.58 ng/g for upland area, 749.46 ng/g for mid-slope area, and 679.37 ng g-1 for Low-land. The concentration of the HMs followed the order of Cu > Cd > Ni > Pb > Cr > Fe > Mn > Zn > Co, with Cu, Cd, Ni, and Pb exceeding the permissible levels. The study areas displayed varying concentrations of NO3-, PO42-, SO42- Ca, Na, and K, with some levels exceeding acceptable values, possibly influenced by crude oil contamination and the use of fertilizers. In the Niger Delta regions, the primary sources of soil PAH contamination include crude oil spills, natural crude oil seepage, and coal combustion. With this, the government of Nigeria should strengthen soil contamination monitoring, enforce spill regulations and promote eco-friendly farming.