中国南方稻田土壤汞含量及潜在危害评价

选择我国南方水稻主产区安徽、浙江、湖南、湖北以及广西5个省,采集213个稻田土壤样品,探究我国南方稻田土壤中汞的空间分布特征与土壤理化参数(如p H值和有机质)的相关关系及汞富集的潜在危害。结果表明:不同省份的稻田土壤汞含量存在显著的差异(P0.05,n=213),含量范围是0.029~0.326 mg·kg~(-1)(干重),平均值为(0.094±0.036)mg·kg~(-1),与农用地土壤环境质量标准0.30 mg·kg~(-1)(GB15618—1995)相比,除湖北省以外均有轻度汞污染。Pearson相关性分析表明,稻田土壤中的汞含量与有机质含量呈显著正相关关系(P0.01,r=0.445),说明适度偏高的有机质有利于土壤汞的富集。不同省份稻田土壤潜在危害等级除浙江省外均在轻微到中等的范围内,浙江省的为强等级。

Mercury Concentrations and Potential Risk Assessment of Paddy Soil in South China

This study was designed to explore the relationship between spatial distribution characteristics of mercury (Hg) and the physicochemical properties (such as pH and organic matter) of paddy soils. The potential risk assessment of Hg in paddy soil ecosystem was also conducted by Potential Ecological Risk Index method. The total 213 paddy soil samples were collected in five provinces, namely Anhui, Zhejiang, Hunan, Hubei and Guangxi Province, which are main rice producing areas in South China. There were significant differences (P < 0.05, n = 213) among Hg concentration in paddy soils from five provinces, which ranged from 0.029 mg?kg^-1 to 0.326 mg?kg^-1 (dry weight) with an average of (0.094±0.036) mg?kg^-1. Except for Hubei Province, the paddy soils from other four provinces were slightly polluted by Hg when compared with 0.30 mg?kg^-1 of soil environmental quality standard for agricultural land in China (GB 15618-1995). Results from Pearson correlation analysis indicated that a positive correlation (P < 0.01, r = 0.445) was observed between organic matter and Hg concentration in paddy soils. It is implied that moderately high content of organic matter can result in the enrichment of Hg in the soil. The potential risk of the Hg-polluted paddy soils is strong in Zhejiang Province, while that of the other four provinces varied from mild to medium.