Physicochemical Assessment of Soils from Selected Metal Scrap Dumpsites in Anambra State, Nigeria

Abstract

Soils are prone to pollution due to the influence of climate change, globalization and industrialization. Soil samples used in this research were collected from two different metal scrap dumpsites while the controls were taken 500m away from sampling sites all in Anambra state, Nigeria. The physico-chemical parameters analyzed were pH, electrical conductivity, total organic carbon (TOC), moisture content, nitrate, phosphate and heavy metals. Heavy metals viz: Cd, Co, Fe, Mn, Pb and Zn concentrations (mg/kg) were determined using Varian AA240 model of atomic absorption spectrophotometer (AAS). The pH and electrical conductivity determinations were done in situ using Searchtech, PHS-7010 multimeter scale. Moisture content of the samples were determined in DHG-9053A oven.  The soil samples in the studied areas contained Cd, Co, Fe, Mn, Pb and Zn. The analysed heavy metals concentrations were attributed to anthropogenic sources and geological formation of the areas since the control samples equally had appreciable concentrations of some of these heavy metals. The pH, EC, salinity, nitrate and phosphate values obtained in this study pose no harm on the soils yet. However, the concentrations of some heavy metals assayed are significantly higher than WHO permissible limit for heavy metals on soils. Therefore, good management of metal scrap activities is highly recommended in Anambra State since metal scrappers occupy most large vacant lands near farm lands, water bodies and human settlements thereby increasing the potency of toxic chemicals in the ecosystem.