Purpose

To make up for the deficiency of the distribution characteristics of mercury (Hg) pollution in soil and rice in a specific area, the relationship between more than ten soil indices and Hg in soil-rice system was analysed, and the main factors affecting mercury accumulation in rice were screened out. So as to provide reliable theoretical and scientific basis for the regulation and safe utilization of Hg-contaminated soil.

Methods

The Hg-polluted area of Siqian Dam, with a paddy field area of 1.34 million square meters, was selected as the research unit. Soil and corresponding rice samples were collected and analysed. Then, common Kriging interpolation was used to explore the spatial distribution differences of mercury content between soil and rice, Pearson correlation analysis and stepwise linear regression were used to analyse the relationship between mercury content and 14 soil indices.

Results

In the study area, the total mercury(THg) content in soil and rice was as high as 30.60 mg/kg and 160.19 µg/kg, respectively, and the methyl mercury(MeHg) content was as high as 14.56 µg/kg and 40.32 µg/kg, respectively, indicating that mercury pollution in soil and rice was serious. The horizontal spatial distribution of soil THg and MeHg was different. Flood with its sediment and topography were the main reasons for the uneven distribution of Hg content in the region. The spatial distribution of Hg was different between rice and soil. There was no significant correlation between rice and soil THg, but there was a significant correlation between rice and soil MeHg content. Among the 14 soil indices, available potassium was a vital index affecting the accumulation of Hg in rice, followed by pH, Zn, Mn and Fe.

Conclusions

The results showed that in weakly acidic and fertile soil, the appropriate reduction of soil pH, OM and available Se and Cr contents could inhibit soil Hg methylation, the reduction of potassium fertilizer application could further reduce rice Hg accumulation.

中文翻译：

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贵州铜仁市典型矿区稻田汞水平空间分布及稻米汞积累及其影响因素

 目的

为弥补特定区域土壤和水稻汞（Hg）污染分布特征的不足，分析了土-水稻系统中十余种土壤指标与Hg的关系，找出影响汞积累的主要因素。大米中的都被筛掉了。从而为汞污染土壤的治理和安全利用提供可靠的理论和科学依据。

 方法

选择司前坝汞污染区为研究单位，水田面积134万平方米。收集并分析土壤和相应的水稻样品。然后采用普通克里格插值法探究土壤和水稻汞含量的空间分布差异，采用Pearson相关分析和逐步线性回归分析汞含量与14个土壤指标的关系。

 结果

研究区土壤和水稻中总汞(THg)含量分别高达30.60 mg/kg和160.19 µg/kg,甲基汞(MeHg)含量高达14.56 µg/kg和40.32 µg/kg。分别为μg/kg，表明土壤和水稻中汞污染严重。土壤THg和MeHg水平空间分布不同。洪水及其沉积物和地形是造成该地区汞含量分布不均匀的主要原因。水稻和土壤中汞的空间分布存在差异。水稻与土壤THg不存在显着相关性，但水稻与土壤MeHg含量存在显着相关性。 14个土壤指标中，速效钾是影响水稻汞积累的重要指标，其次是pH、Zn、Mn和Fe。

 结论

结果表明，在弱酸性、肥沃的土壤中，适当降低土壤pH、OM和有效硒、有效铬含量可以抑制土壤汞甲基化，减少钾肥施用可以进一步减少水稻汞积累。