State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, P. R. China.
University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
Environ Sci Technol. 2020 Mar 17;54(6):3228-3236. doi: 10.1021/acs.est.9b06486. Epub 2020 Mar 5.
Mercury (Hg) bioaccumulation in rice poses a health issue for rice consumers. In rice paddies, selenium (Se) can decrease the bioavailability of Hg through forming the less bioavailable Hg selenides (HgSe) in soil. Rice leaves can directly uptake a substantial amount of elemental Hg from the atmosphere, however, whether the bioaccumulation of Hg in rice leaves can affect the bioaccumulation of Se in rice plants is not known. Here, we conducted field and controlled studies to investigate the bioaccumulation of Hg and Se in the rice-soil system. In the field study, we observed a significantly positive correlation between Hg concentrations and BAFs of Se in rice leaves ( = 0.60, < 0.01) collected from the Wanshan Mercury Mine, SW China, suggesting that the bioaccumulation of atmospheric Hg in rice leaves can facilitate the uptake of soil Se, perhaps through the formation of Hg-Se complex in rice leaves. This conclusion was supported by the controlled study, which observed significantly higher concentrations and BAFs of Se in rice leaf at a high atmospheric Hg site at WMM, compared to a low atmospheric Hg site in Guiyang, SW China.
汞（Hg）在水稻中的生物累积对食用水稻的人群的健康构成威胁。在稻田中，硒（Se）可以通过在土壤中形成生物利用度较低的 Hg 硒化物（HgSe）来降低 Hg 的生物可利用性。然而，水稻叶片可以直接从大气中大量吸收元素 Hg，目前尚不清楚水稻叶片中 Hg 的生物累积是否会影响水稻植株中 Se 的生物累积。在这里，我们进行了田间和控制研究，以调查 Hg 和 Se 在水稻-土壤系统中的生物累积。在田间研究中，我们观察到来自中国西南万山汞矿区的水稻叶片中 Hg 浓度与 Se 的生物浓缩因子（BAFs）之间存在显著正相关（ = 0.60， < 0.01），这表明大气 Hg 在水稻叶片中的生物累积可以促进土壤 Se 的吸收，这可能是通过在水稻叶片中形成 Hg-Se 配合物。在中国西南贵阳的低大气 Hg 位点与万山汞矿区的高大气 Hg 位点相比，控制研究观察到水稻叶片中 Se 的浓度和 BAFs 明显更高，这一结论得到了支持。
