Study on the Ecotoxic Effects of Uranium and Heavy Metal Elements in Soils of a Uranium Mining Area in Northern Guangdong

Abstract

To investigate the heavy metal contamination of soil in a uranium mining area in northern Guangdong, a physicochemical evaluation method was used to evaluate the contaminated soil near the pit and tailings pond of the uranium mining area, determine its heavy metal content and evaluate its ecological risk using the Nemerow integrated contamination index, ground accumulation index and potential ecological risk index. The results show that the average content of nine heavy metal elements in the soil of the uranium mining area exceeds the background value of red soil in Guangdong Province. Three pollution evaluation indices all indicate that Cd, As and U have serious pollution and high ecological risk, while the remaining elements are weakly polluted and the potential ecological risk of the six sampling sites all show very strong risk. On this basis, soil ecotoxicity was evaluated using ostracods (Cypridopsis vidua and Heterocypris sp.), Vibrio fischeri and Vicia faba L. Higher concentrations of heavy metals at individual sites (T1, T2, P2) resulted in higher mortality of ostracods, higher inhibition of Vibrio fischeri luminescence and a significant reduction in germination and pigmentation of broad beans. The results of the biotoxicity evaluation were consistent with the results of the physicochemical evaluation, allowing for a more direct and comprehensive evaluation of the ecotoxic effects of uranium and heavy metals in the mine soils.

Untitled

“…Due to need to concentrate one of its isotope for being used as a military weapon or fuel in a nuclear reactor, the industrial process involved, the waste dumped in the planet and the residues in atomic bomb explosions and leaks in nuclear reactors, made this toxic radioactive element more concentrated in the surface of the Earth than wanted [46, [53][54][55]. Its presence in the air and in the soil, especially the so-called depleted uranium (depleted of its isotope 238) is reported and is the main source of contamination of crops and humans [56][57][58][59]. In 1985, the NIH published in the site the concentrations of uranium found in some foods in the USA.…”

Identification of the single and combined acute toxicity of Cr and Ni with Heterocypris sp. and the quantitative structure-activity relationship (QSAR) model

“…They have been widely used in the study of the toxicity of single or mixed heavy metals (ppb-ppm) in water [ 10 – 12 ], soil [ 13 – 16 ], and sediments [ 17 , 18 ]. Zhang et al [ 19 ] investigated the soil heavy metal pollution in a uranium mine in South China, using Cypridopsis vidua and Heterocypris sp. to assess the soil ecological toxicity.…”