Heavy Metal Contamination, Source Identification, Human Health Risk and Sustainability Assessment of Soils Across Industrial, Agricultural, and Residential Land-Use Areas in Rivers State, Nigeria

Abstract

Heavy metal contamination poses significant ecological and public health concerns due to its persistence, toxicity, and bioaccumulative potential of toxic metals, threatening environmental quality and sustainable development. This study evaluated the distribution, pollution status, health risks, and sources of heavy metals in soils from industrial, agricultural, and residential areas of Rivers State, Nigeria, using Inductively Coupled Plasma–Mass Spectrometry (ICP-MS). Elevated concentrations of As, Mn, Se, Zn, and Co were detected across the study locations. Arsenic recorded the highest concentration in the Trans-Amadi industrial area (366.8 mg/kg), while Mn and Zn reached maximum concentrations of 1312 mg/kg and 327.9 mg/kg in Woji and Egi, respectively, exceeding the DPR limits for soil HMs. Pollution indices, including contamination factor, geo-accumulation index, enrichment factor, pollution load index, and Nemerow Integrated Pollution Index, revealed moderate to severe contamination, with the industrial zone exhibiting a NIPI value of 12.5. Health risk assessment identified ingestion as the dominant exposure pathway. Hazard quotient values for As (9.15) in the children category exceeded USEPA-acceptable limits, indicating potential non-carcinogenic risks. Carcinogenic risk assessment identified arsenic as the principal carcinogenic contaminant, with ingestion-derived Incremental Lifetime Cancer Risk (ILCR) values in the industrial area exceeding the USEPA maximum acceptable lifetime cancer risk threshold (1 × 10−4), particularly among children, whereas the carcinogenic risks associated with the other investigated metals generally remained within acceptable or tolerable limits. Source identification indicated that industrial emissions, vehicular activities, waste disposal, and agricultural practices were the primary contributors to heavy metal accumulation. These findings provide critical scientific evidence for targeted remediation, pollution prevention, and informed health-risk environmental management to protect soil quality, ecosystem integrity, and public health. The study supports evidence-based policies that advance sustainable land management, environmental protection, and progress in Rivers State, Nigeria.