Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA, Australia.
Sci Total Environ. 2011 Jan 15;409(4):853-60. doi: 10.1016/j.scitotenv.2010.11.003. Epub 2010 Dec 4.
The mobility and bioavailability of lead (Pb) in soils can be mitigated by its immobilization using both soluble and insoluble phosphate (P) compounds. The effectiveness of insoluble P sources on Pb immobilization depends on their rate of dissolution which can be enhanced by phosphate solubilizing bacteria (PSB). In this study, the effect of soluble (potassium dihydrogen phosphate) and insoluble (rock phosphate in the presence and absence of PSB) P compounds on the immobilization of Pb, and leaching of Pb and P was examined using both naturally contaminated (SR soil: NH₄NO₃ extractable Pb: 28.7 mg/kg, pH: 5.88, organic matter: 0.7%) and Pb spiked (AH soil: NH(4)NO(3) extractable Pb: 42.7 mg/kg, pH: 5.23, organic matter: 10.9%) soils. Phosphate compounds were added at the rate of 200 mg P/kg and 800 mg P/kg for SR and AH soils, respectively. Soluble P treatment immobilized 80% and 57% of Pb in SR and AH soils, respectively. Insoluble rock phosphate immobilized 40% and 9% of Pb without PSB, and 60% and 17% with PSB in SR and AH soils, respectively. Lead leaching was the lowest when soils were amended with rock phosphate in the presence of PSB, which reduced Pb leaching by 36% for SR soil and 18% for AH soil compared to the control. The leaching of Pb increased when the soils were amended with soluble P because soluble P treatment increased dissolved organic carbon (DOC) concentration of soil, thereby increasing Pb mobility. Soluble P treatment significantly increased P leaching and 9% of total added P was leached from low P retaining AH soil. The optimum level of P amendment is a critical issue when soluble P is used as a Pb immobilizing agent because of eutrophication resulting from excessive P leaching to surface and ground water. While the soluble P compound was effective in the immobilization of Pb, it resulted in P leaching which increased with increasing levels of P addition. However, rock phosphate amendment with PSB achieved the immobilization of Pb with a minimum effect on both Pb and P leaching.
土壤中铅（Pb）的迁移性和生物可利用性可以通过使用可溶性和不溶性磷酸盐（P）化合物将其固定化来减轻。不溶性 P 源对 Pb 固定化的有效性取决于其溶解速率，而这可以通过磷酸盐溶解菌（PSB）来增强。在这项研究中，使用天然污染（SR 土壤：NH₄NO₃可提取 Pb：28.7 mg/kg，pH：5.88，有机质：0.7%）和 Pb 污染（AH 土壤：NH(4)NO(3)可提取 Pb：42.7 mg/kg，pH：5.23，有机质：10.9%）土壤，研究了可溶性（磷酸二氢钾）和不溶性（存在和不存在 PSB 时的磷矿粉）P 化合物对 Pb 固定化和 Pb 和 P 浸出的影响。磷酸盐化合物的添加量分别为 SR 和 AH 土壤的 200 mg P/kg 和 800 mg P/kg。可溶性 P 处理分别固定了 SR 和 AH 土壤中 80%和 57%的 Pb。在没有 PSB 的情况下，不溶性磷矿粉固定了 SR 和 AH 土壤中 40%和 9%的 Pb，而有 PSB 时则分别固定了 60%和 17%的 Pb。与对照相比，当土壤中添加 PSB 存在的磷矿粉时，Pb 的浸出量最低，SR 土壤的 Pb 浸出量减少了 36%，AH 土壤的 Pb 浸出量减少了 18%。当土壤中添加可溶性 P 时，Pb 的浸出量增加，因为可溶性 P 处理增加了土壤中溶解有机碳（DOC）的浓度，从而增加了 Pb 的迁移性。可溶性 P 处理显著增加了 P 的浸出量，而从低磷保持 AH 土壤中浸出了 9%的总添加 P。当可溶性 P 用作 Pb 固定剂时，P 添加剂的最佳水平是一个关键问题，因为过量 P 浸出到地表水和地下水会导致富营养化。虽然可溶性 P 化合物有效地固定了 Pb，但它导致 P 浸出量增加，而随着 P 添加量的增加，P 浸出量也增加。然而，添加 PSB 的磷矿粉处理实现了 Pb 的固定化，同时对 Pb 和 P 的浸出影响最小。
