低温热解处理汞污染土壤对蔬菜总汞和甲基汞累积的影响

Effects of Low-temperature Pyrolysis of Mercury-contaminated Soil on the Accumulation of Total Mercury and Methylmercury in Vegetables

低温热解技术是汞污染土壤修复的有效工程措施之一,能降低土壤环境风险。本文选择矿区汞污染土壤进行低温热解修复并开展蔬菜种植,探索低温热解前后土壤理化性质和汞含量的变化,研究低温热解修复对土壤中总汞和甲基汞向蔬菜迁移及累积的影响。结果表明,低温热解后,土壤中有效磷提高了828.0%,阳离子交换量、有机质、全氮、碱解氮含量不同程度降低;土壤总汞去除率为86.63%,甲基汞去除率为95.34%;低温热解后土壤生长的白菜、白萝卜、小白菜、豌豆可食部位总汞、甲基汞含量分别降低了16.67%、36.36%、50.00%、50.00%和63.16%、37.50%、26.67%、22.22%。研究结果可为评估低温热解技术对汞污染土壤的治理修复成效提供数据参考。

Low-temperature pyrolysis technology is one of the effective engineering measures for remediation of mercury-contaminated soil, which can reduce soil environmental risks. In this paper, mercury-contaminated soil in mining area was selected for low-temperature pyrolysis remediation and vegetable planting. The changes of soil physical and chemical properties and mercury level before and after low-temperature pyrolysis were explored. The effects of low temperature pyrolysis remediation on the migration and accumulation of total mercury and methylmercury in soil to vegetables were studied. The results showed that after low-temperature pyrolysis, soil available phosphorus increased by 828.0%, CEC, organic matter, total nitrogen and alkali-hydrolyzable nitrogen decreased in varying degrees. The total mercury removal rate was 86.63%, and the methyl-mercury removal rate was 95.34%. The total mercury and methylmercury content in edible parts of Chinese-cabbage, radish, cabbage and pea decreased by 16.67%, 36.36%, 50.00%, 50.00% and 63.16%, 37.50%, 26.67%, 22.22% respectively after low-temperature pyrolysis. The results of this study can provide data reference for evaluating the remediation effect of low-temperature pyrolysis technology on mercury-contaminated soil.