Occurrences and toxicological risk assessment of eight heavy metals in agricultural soils from Kenya, Eastern Africa.
The concentration distribution and toxicological assessment of eight heavy metals including lead (Pb), cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), mercury (Hg), arsenic (As), and zinc (Zn) in agricultural soils from Kenya, Eastern Africa, were investigated in this study. The results showed mean concentrations of eight heavy metals of Zn, Pb, Cr, Cu, As, Ni, Hg, and Cd in agricultural soils as 247.39, 26.87, 59.69, 88.59, 8.93, 12.56, 8.06, and 0.42 mg kg(-1), respectively. These mean values of eight heavy metals were close to the toxicity threshold limit of USEPA standard values of agricultural soils, indicating potential toxicological risk to the food chain. Pollution index values revealed that eight heavy metals severely decreased in the order Hg > Cd > As > Cu > Pb > Zn > Ni > Cr and the mean value of the overall pollution index of Hg and Cd was 20.31, indicating severe agriculture ecological risk. Potential pollution sources of eight heavy metals in agricultural soils were mainly from anthropogenic activities and natural dissolution. The intensification of human agricultural activities, the growing industrialization, and the rapid urbanization largely influenced the concentration levels of heavy metals in Kenya, Eastern Africa. Moreover, the lack of agricultural normalization management and poor enforcement of environmental laws and regulations further intensified the widespread pollution of agricultural soils in Kenya.
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.|Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
Teresiah Muciku
TM
Mungai
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.|Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
Anita Awino
AA
Owino
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.|Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
Victorine Anyango
VA
Makokha
Wuhan Environmental Protection Bureau, Wuhan, 430022, China.
Yan
Y
Gao
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.|Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China.
Xue
X
Yan
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China. wangjun@wbgcas.cn.|Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, 430074, China. wangjun@wbgcas.cn.
Jun
J
Wang
D000383:Agriculture; D007630:Kenya; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity
D019216:Metals, Heavy; D012989:Soil Pollutants
Agriculture ecological risk; Concentrations; Eastern Africa; Heavy metals; Kenya; Toxicological risk assessment