会泽铅锌矿区农田土壤镉、铅和养分分布特征及污染评价

Distribution and Evaluation of Nutrient and Cd/Pb Content in Agricultural Soils in Huize Lead-Zinc Mine Area

【目的】了解会泽铅锌矿区农田土壤镉、铅和养分分布特征,探究镉、铅含量与形态和养分之间的相关性。【方法】采集0～60 cm的农田土壤,测定土壤中镉、铅与养分含量,利用单因子污染指数法、内梅罗多因子综合污染指数法和潜在生态风险评价法,评价土壤中镉、铅污染程度。【结果】(1) 0～20 cm农田土壤镉、铅污染严重。土壤镉污染达到重度污染水平(P_i、P_N>3),毗邻矿山和远离矿山土壤铅污染分别处于重度污染(P_i、P_N>3)和安全范围(PN<0.7)。矿区土壤镉、铅污染分别为高生态风险(E_i>110)和安全生态风险(E_i<55)。(2)镉、铅主要以残渣态存在于土壤中,占比为52.54%和50.26%。矿区土壤潜在生物可利用态铅和毗邻矿山土壤潜在生物可利用态镉的质量分数较高(>44%)。(3)矿区农田土壤养分水平较低,远离矿山采样点土壤养分含量平均高于毗邻矿山采样点。全量和可交换态镉、铅含量与全磷、速效磷含量呈显著(P<0.05)或极显著(P<0.01)负相关。【结论】矿区农田土壤镉的污染程度和生态风险均高于铅,磷与镉、铅之间相关性显著。

[Purpose]To investigate the distribution and pollution evaluation of cadmium(Cd) and lead(Pb), and to explore the correlation between nutrient and heavy metal forms in agricultural soil in Huize lead-zinc mine area. [Method]We collected 0-60 cm soil and analyzed the Cd and Pb and soil nutrient content. The risks of Cd and Pb were evaluated using the single factor index evaluation method and Nemerow integrated index method and potential ecological risk index proposed by Hakanson. [Result](1) 0-20 cm soil has seriously Cd and Pb pollution than other depth. The pollution of Cd has achieved the high levels(P_i, P_N>3). The pollution of Pb were high levels(P_i, P_N>3)and safety scope(PN<0.7) pollution in adjacent and far away mine sampling points of agricultural soil,respectively. There were high potential ecological risk of Cd pollution(Ei>110) and safe range of ecological risk for Pb pollution(E_i<55) in all soils.(2) Cd and Pb mainly existed as residual fraction and proportion for 52.54% and 50.26%. The potential bio-available of Pb in all soils and the potential bioavailable of Cd in adjacent mine sampling points of agricultural soil were higher than 44%.(3) Agricultural soil had a low nutrient level in mine area. The nutrient content of adjacent mine sampling points of agricultural soil were higher than far away sampling points. Total and exchangeable Cd and Pb contents had the negative correlation with the total and available phosphorus content(P<0.05 or P<0.01). [Conclusion]The pollution and ecological risk of Cd were higher than Pb and it was significant correlation between Cd, Pb and phosphorus.