酸雨条件下化肥中重金属的生物可利用性研究

Bioavailability of heavy metal in different chemical fertilizers under simulated acid rain

选用市面上常见的磷肥和复合肥,通过人为模拟不同酸雨环境,对其溶解时释放重金属的特点及所含重金属的生物可利用性进行了研究.结果表明,供试化肥样本中重金属总量均未超过限量标准,且磷肥中重金属的含量和溶解性均高于复合肥.不同酸雨环境对As、Cd和Cu的生物可利用性影响不大,Cr、Pb和V在pH为3.0的酸雨条件下,生物可利用性最高.化肥中重金属的溶解性由大到小排序为As、Cd、Cu、V、Cr、Pb,其溶解性受重金属总量、溶剂pH和化肥中其他离子的综合影响.相比于重金属总量,其可溶态含量更能反映出生物可利用性的程度.因此,可溶态重金属的含量应作为评判化肥施用潜在环境风险的重要指标.

Different acid rain environment was used to simulate release of heavy metals and bioavailability of heavy metals from both common phosphate fertilizers and compound fertilizers. The content of heavy metal did not exceed limits, heavy metals in phosphate fertilizer was higher than compound fertilizers. Acid rain environment was found to have little effect on bioavailability of As, Cd and Cu. Bioavailability of Cr, Pb and V was greatest at pH 3.0. The order of heavy metal solubility in chemical fertilizer was As〉Cd〉Cu〉V〉Cr〉 Pb, influenced by total amount of heavy metals, solvent pH and other ions. Compared with total amount of heavy metals, soluble content can better reflect bioavailability. Soluble heavy metal content should be evaluated as an important indicator of potential environmental risks of chemical fertilizers.