Pollution loads and the ecological risk assessment of soil heavy metals around a mega cement factory in Southwest Nigeria

Cement production is noted for particulate pollution of the environment because of high dust emissions and heavy metals that later deposited in soils, serving as a sink. This study aimed to assess the concentrations and potential ecological risk of heavy metals around a mega cement factory in southwest Nigeria. Soil samples were randomly collected in the eastern, western, and southern axes of the factory. The samples were subjected to Nitric-perchloric acid digestion, and an atomic absorption spectrophotometer was used to determine the concentrations of Pb, Cu, Cd, Cr, and Zn. Data were analyzed with ANOVA and Duncan Multiple Range Test. The results showed that the mean concentrations of Pb, Cu, Cd, and Cr (666.1 mg/kg, 613.4 mg/kg, 547.9 mg/kg, and 188.5 mg/kg, respectively) were above the international standard limits. Nemerow pollution indices, according to the axes, indicated serious pollution with heavy metals. The Single Potential Ecological Risk Index (PERI) showed that soil contamination from Cd in the 3 axes had very high potential ecological risk, which translated into the high value of Comprehensive Potential Ecological Risk (RI) value (11,488.3) for the entire study area. The urgent need for the bioremediation of the soil around the cement factory, especially for Cd, is needed to avert a potential environmental disaster.