Natural Attenuation of Heavy Metals and Explosive Residues at Military Demolition Sites in Agrarian Ecosystems

Abstract

This study investigated the natural attenuation of heavy metals and explosive residues resulting from military ammunition demolition activities in agrarian ecosystems of Nigeria, with Alamala serving as the primary focus. It examined the environmental and health risks associated with both historical and current disposal practices, evaluating the persistence and reduction of contaminants such as RDX, TNT, HMX, perchlorate, and various heavy metals. Seasonal and spatio-temporal sampling was conducted across soil, water, air, and vegetation in the demolition zones and surrounding communities. Samples were analysed for physicochemical parameters including pH, BOD, COD, TDS, and metal concentrations. The results revealed consistent patterns in iron and zinc levels, notable fluctuations in copper, and elevated concentrations of lead, particularly at the Alamala site. Seasonal variations influenced contaminant migration, with chloride and sulphate dominating the water chemistry. Explosive residues and heavy metals showed distinct attenuation behaviours across environmental compartments. Over a 90-day post demolition period, contaminant concentrations changed at varying rates, reflecting the natural remediation processes occurring in soil, water, and plants. Statistical analyses, including time series and regression models, identified compartment-specific attenuation rates and highlighted the complex interactions between environmental factors and contaminant behaviour. The study provided critical insights into the ecological impacts of demolition activities, contributing to informed risk assessment and environmental policy development in militarized agrarian regions.