Uranium contamination of milk from cattle in the uranium-mining area in Siavonga District of Zambia: a preliminary human health risk assessment
Titus Haakonde, John Yabe, Kennedy Choongo, Gershom Chongwe, Gilbert Nchima, Md. Saiful Islam
Abstract
Abstract Background Contamination of cow milk with uranium (U) is attracting global attention owing to U’s radio-toxicity and chemical toxicity in humans and animals. Concentrations of U in 223 cow milk samples from indigenous breeds reared in the proximity of a U mine in Zambia were measured using the inductively coupled mass spectrometry, and the human health risks from exposure to U through milk consumption were assessed. Results Milk from cattle reared in the U-mining area showed a significantly higher U-mean concentration (0.83 ± 0.64 µg/L; t = 9.95; tα = 0.05, p > 0.05) than milk from cattle reared in the non-mining area (0.08 µg/L ± 0.05). Among the residents of the U-mining area, the mean estimated daily intake (EDI), the target hazard quotients (THQs) and the target carcinogenic risks (TCRs) were all significantly ( p < 0.05) elevated than among the residents of the non-mining area. Conclusions Since the EDIs, THQs and TCRs and the U level in the cow milk were all within the World Health Organization’s and the United States Environmental Protection Agency’s permissible limits of 0.6 µg/kg-bw/day, < 1, < 10 –4 and 30 µg/L, respectively. The current study, therefore, has insufficient evidence to implicate U exposure through consumption of cow milk in any non-carcinogenic or carcinogenic human health complications that are currently prevailing in the study area. Graphic abstract