万山汞矿区水稻吸收无机汞及甲基汞影响因素探讨

为了探讨贵州万山汞矿区土壤等因素对水稻吸收无机汞和甲基汞的影响,通过在万山垢溪、熬寨、四坑和五坑典型区域采集水稻和土壤样品进行测试,利用相关分析研究了水稻在分蘖期吸收无机汞和甲基汞的影响因素。研究表明水稻根与茎中积累的无机汞含量和土壤中无机汞含量显著正相关(r=0.987和0.786),而叶中无机汞含量与土壤pH显著负相关(r=-0.645),与土壤中总硫显著正相关(r=0.621)。水稻根和叶吸收的甲基汞含量与土壤中甲基汞含量显著正相关(r=0.710和0.599),但与土壤中其他参数没有明显的相关性。垢溪水稻根表铁膜量高于其他区域,根表铁膜吸附无机汞与水稻根吸收无机汞具有显著的正相关关系(r=0.891),而吸附的甲基汞并没有与根中甲基汞存在相关性。因此,在万山汞矿区,土壤中无机汞和甲基汞含量是影响水稻吸收无机汞和甲基汞的关键因素,同时反映出水稻对甲基汞和无机汞的吸收存在不同的路径。

Investigation of the factors affecting the absorption of inorganic mercury and methylmercury by rice in the Wanshan mercury mining area

The health risk caused by the accumulation of mercury(Hg) and methylmercury(MeHg) in rice grain has gained increasing attention. To investigate the factors that affect the uptake of inorganic Hg and MeHg in rice in the Wanshan mercury mine area of Guizhou Province, rice plant and soil samples were collected at Gou Xi village, Aozhai village, and Sikeng and Wukeng. Using correlation analysis, we investigated the effects of soil factors, such as inorganic Hg and sulfur content, soil pH, total sulfur, organic matter, and MeHg, on the absorption of methylmercury and inorganic mercury by rice at the tillering stage. The results showed that the contents of inorganic Hg in the roots and stems of rice and in soil were positively correlated(r=0.987 and 0.786, respectively). There was a further negative correlation between inorganic Hg in rice leaves and soil pH value(r=-0.645), and a positive correlation between inorganic Hg in leaves and total sulfur in soil(r=0.621). A positive correlation was also found between the concentration of MeHg in roots and leaves and that in soil(r=0.710 and 0.599, respectively). However, there were no significant correlations with other soil parameters such as total sulfur, inorganic Hg, organic matter, and pH value. The amount of iron plaque on the roots of rice at Gou Xi was greater than that at the other sites, and there was a posi tive correlation between the content of inorganic Hg in roots and the adsorption of iron plaque(r=0.891). No similar relationship was detected for MeHg. The findings of this study showed that the content of inorganic Hg and MeHg in the soil was the key factor influencing the absorption of inorganic Hg and MeHg by rice plants in the Wanshan mercury mine area, and indicated that there were different paths for the absorption of inorganic Hg and MeHg in rice.