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.
