Risk Assessment of Heavy Metals and Endocrine Disruptive Compounds in Water, Sediment, and Biota in Igbariam, Anambra State

Abstract

Riverine communities across Nigeria's Niger-Benue and associated tributary systems, including the Anambra (Omambala) River system bordering Igbariam, face documented risks of heavy metal and endocrine disruptive compound (EDC) contamination linked to agricultural runoff, artisanal and small-scale mining activity upstream, inadequate wastewater management, and, in some catchments, oil and gas-related activity. This paper presents a risk assessment framework for evaluating heavy metal and endocrine disruptive compound contamination in water, sediment, and biota within the Igbariam area of Anambra State, synthesizing established environmental risk assessment methodologies with findings drawn from comparable published studies of Nigerian surface water systems. Rather than presenting original laboratory sampling data, which was outside the scope of this desk-based study, the paper develops and specifies a comprehensive risk assessment protocol, encompassing sampling design across water, sediment, and biota matrices, target contaminant selection informed by regional land-use and industrial activity patterns, appropriate analytical methods, and the calculation of standard risk indices, including hazard quotients, hazard indices, and bioaccumulation factors, that would be required to generate a rigorous, site-specific risk characterization for the Igbariam area. The paper reviews documented contamination patterns and associated ecological and human health risks reported in comparable Nigerian riverine and tributary systems, and uses this comparative evidence to identify the specific heavy metals (including lead, cadmium, mercury, and chromium) and endocrine disruptive compound classes (including phthalates, bisphenol A, and certain organochlorine pesticide residues) most warranting priority investigation in the Igbariam context. The paper concludes that a formally executed empirical risk assessment following the proposed framework is warranted given the documented contamination patterns in comparable regional water systems and the direct human exposure pathways associated with the Igbariam community's reliance on local water resources for domestic and agricultural use.