Total mercury distribution in different crops at Wanshan mercury mining area, China: implication for managing mercury risk

Jicheng Xia a,b, C. W.N. Andersonc, J. Wang a and X. Feng a

a Institute of Geochemistry, Chinese Academy of Sciences, P.R. China

b College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, P.R. China

c Institute of Agriculture and Environment, Massey University, New Zealand

xiajicheng@mail.gyig.ac.cn

Soil surrounding mercury (Hg) mining areas (MMAs) is heavily contaminated with Hg, causing Hg contamination in crops grown from the soil. The inhabitants living in MMAs are exposed to Hg by consumption of Hg-contaminated crops. Therefore, the management for safety crop production at MMAs is necessary to protect the human health. Wanshan mercury mining area (WMMA) located Guizhou province, China, was studied to screen the crops that are low Hg accumulative, based on the distribution of Hg in air, soil and crops. The Hg concentrations in the atmospheres at the study sites greatly exceeded those at background sites. Mercury concentrations in soil range from 0.6 to 943.6 mg kg-1. The total Hg concentrations in the edible parts of 43 types of crops vary greatly from 2.4 to 1274.9 μg kg-1. The edible part of five of the crops (radish, strawberries, corn and potato), which were grown within respective soil Hg concentrations, had Hg concentrations lower than the Chinese National Food Quality Standard. We plant these four category crops into two Hg-contaminated farmlands in the second year, had Hg concentrations lower, too. These crops are deemed low Hg accumulative crops. Based on these results and on the database of land use, a safety agricultural regulation scheme is proposed, which can largely ensure the original agricultural use of farmland and the benefits to farmers by encouraging them to grow these low Hg-accumulative crops. By adapting to this new scheme, the Hg exposure in local inhabitants in MMAs could be significantly reduced.

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