Analysis of Soil Geochemistry Around Industrial Zones in Port Harcourt, Rivers State

Industrial activities in Port Harcourt, the commercial hub of Rivers State in the South South geopolitical zone, have generated concerns about soil geochemical contamination resulting from petroleum refining, chemical manufacturing, and transport emissions. This study analyses the geochemical characteristics and heavy metal loading of topsoils collected from industrial zones and adjacent residential areas in Port Harcourt, with a focus on petroleum-related contaminants and metallic pollutants. Soil samples were collected at a depth of zero to fifteen centimetres from a systematic sampling grid encompassing industrial estates and three residential neighbourhoods at varying distances from emission sources. Total petroleum hydrocarbons were determined by gas chromatography after n-hexane extraction, while heavy metals including zinc, copper, nickel, vanadium, and barium were quantified by inductively coupled plasma optical emission spectrometry following aqua regia digestion. Contamination assessment employed geo-accumulation indices, pollution load index, and principal component analysis to identify contamination sources and pathways. Results are contextualised against background geochemical data for unimpacted soils in the region. The study identifies elevated vanadium and nickel consistent with petroleum-derived contamination in soils near the refinery corridor. Findings are reported to the Rivers State Environmental Protection Agency and the National Oil Spill Detection and Response Agency. Keywords: soil geochemistry, heavy metals, Port Harcourt, industrial contamination, petroleum hydrocarbons.