"Investigation Of Concentration Levels And Associated Risks Of Selected Heavy Metals In Niger Seed Crop And Supporting Soil Produced Around Cement Factories In Adea Berga District Of West Showa Zone, Oromia Regional State, Ethiopia"

Abstract

Economic activities including urbanization, industrial activities, and agricultural intensification practices contribute to environmental pollution and pose undesirable human health effects. In this study concentration levels and associated risks of selected heavy metals (HMs) in Niger seed (Guizotia abyssinica Cass.) and supporting soil were investigated after collecting from agricultural lands surrounding three cement factories (Dangote (DCF), Bedrock (BCF), and Mugher (MCF)) in the Adea Berga districts of West Showa Zone, Ethiopia. The determination of HMs was performed using Flame Atomic Absorption Spectrometer (FAAS) following the digestion of the samples using oxidizing inorganic acids. The used analytical method was validated for its linearity (r2 = 0.994 – 0.999), precision (%RSD = 0.0003 – 4.18%), and accuracy (Recovery = 88.9 – 97.8%). The studied heavy metals were ubiquitously measured in both soil and Niger seed samples across the different sampling sites. The results of the study showed that the studied heavy metals (Ni, Co, Ni, Cr, Cd, Pb, Zn, Cu) were found in the mean range of 3.4 ±0.30 - 1299.5±1.7, 3.00±0.36 - 1501.9±35.4, and 3.30±0.20 - 2038.7±184.2 in mg.kg in soil samples taken from nearby of DCF, BCF and MCF cement factories, respectively. Similarly, in the Niger grain samples the measured mean concentration values of the HMs were lied in the range of 2.43±0.31 - 52.33±0.25, 1.33±0.58 - 38.02±0.25, and ND - 34.07± 0.09 in mg/kg for the samples collected from agricultural field in the vicinity of DCF, BCF and MCF cement factories, respectively. Higher concentration levels of the studied HMs were observed in both samples collected in the vicinity of MCF. Cd and Pb showed high bioaccumulation as the transfer factor result indicated. The human health risk assessment results revealed that Ni, Cd, and Cr are the major health concern under both non-carcinogenic and carcinogenic risks, particularly to children. The pollution assessment result indicated that Ni, Mn, Zn and Cu are the priority concern to the agricultural soil of the study area. Moreover, the ecological risk assessment results depicted that the studied heavy metals pose low ecological risk to the agricultural ecosystem of the study area. The study highlights the Possible HMs contamination in agricultural soils and crops grown near cement factories, emphasizing the need for regular monitoring and mitigation strategies to protect human and environmental health.