Park Jin Hee, Bolan Nanthi S, Chung Jae Woo, Naidu Ravi, Megharaj Mallavarapu
Centre for Environmental Risk Assessment and Remediation (CERAR), University of South Australia, Mawson Lakes, SA 5095, Australia.
J Environ Monit. 2011 Aug;13(8):2234-42. doi: 10.1039/c1em10275c. Epub 2011 Jul 11.
Lead is a highly toxic element and forms stable compounds with phosphate, which is commonly used to immobilize Pb in soils. However, few studies have monitored the long-term stability of immobilized Pb, which is a critical factor in determining the effectiveness of the in situ stabilization technique. Both soluble and insoluble phosphate compounds were tested for Pb immobilization, and its subsequent mobility and bioavailability in a contaminated soil from a shooting range. Adding tricalcium phosphate, hydroxyapatite, rock phosphate and potassium dihydrogen phosphate reduced the concentration of ammonium-nitrate-extractable Pb in the contaminated soil by 78.6%, 48.3%, 40.5% and 80.1%, respectively. Insoluble phosphate amendments significantly reduced leached Pb concentration from the column while soluble potassium dihydrogen phosphate compound increased P and Pb concentrations in the leachate. Rock phosphate reduced Pb accumulation in earthworms by 21.9% compared to earthworms in the control treatment. The long-term stability of immobilized Pb was evaluated after 2 years' incubation of the contaminated soil with rock phosphate or soluble phosphate compounds. Bioavailable Pb concentration as measured by simple bioavailability extraction test (SBET) showed the long-term stability of immobilized Pb by P amendments. Therefore, Pb immobilization using phosphate compounds is an effective remediation technique for Pb-contaminated soils.
铅是一种剧毒元素，能与磷酸盐形成稳定化合物，磷酸盐常用于固定土壤中的铅。然而，很少有研究监测固定化铅的长期稳定性，而这是决定原位稳定技术有效性的关键因素。对可溶性和不溶性磷酸盐化合物进行了铅固定化测试，以及其在某射击场污染土壤中的后续迁移性和生物有效性测试。添加磷酸三钙、羟基磷灰石、磷矿石和磷酸二氢钾后，污染土壤中硝酸铵可提取铅的浓度分别降低了78.6%、48.3%、40.5%和80.1%。不溶性磷酸盐改良剂显著降低了柱中铅的淋溶浓度，而可溶性磷酸二氢钾化合物则增加了渗滤液中磷和铅的浓度。与对照处理中的蚯蚓相比，磷矿石使蚯蚓体内铅的积累减少了21.9%。在用磷矿石或可溶性磷酸盐化合物对污染土壤进行2年培养后，评估了固定化铅的长期稳定性。通过简单生物有效性提取试验（SBET）测得的生物可利用铅浓度表明了磷改良剂对固定化铅的长期稳定性。因此，使用磷酸盐化合物固定铅是一种修复铅污染土壤的有效技术。
