Seshadri B, Bolan N S, Choppala G, Kunhikrishnan A, Sanderson P, Wang H, Currie L D, Tsang Daniel C W, Ok Y S, Kim G
Global Institute for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), P.O. Box 486, Salisbury, SA 5106, Australia.
Global Institute for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), P.O. Box 486, Salisbury, SA 5106, Australia.
Chemosphere. 2017 Oct;184:197-206. doi: 10.1016/j.chemosphere.2017.05.172. Epub 2017 Jun 5.
Shooting range soils contain mixed heavy metal contaminants including lead (Pb), cadmium (Cd), and zinc (Zn). Phosphate (P) compounds have been used to immobilize these metals, particularly Pb, thereby reducing their bioavailability. However, research on immobilization of Pb's co-contaminants showed the relative importance of soluble and insoluble P compounds, which is critical in evaluating the overall success of in situ stabilization practice in the sustainable remediation of mixed heavy metal contaminated soils. Soluble synthetic P fertilizer (diammonium phosphate; DAP) and reactive (Sechura; SPR) and unreactive (Christmas Island; CPR) natural phosphate rocks (PR) were tested for Cd, Pb and Zn immobilization and later their mobility and bioavailability in a shooting range soil. The addition of P compounds resulted in the immobilization of Cd, Pb and Zn by 1.56-76.2%, 3.21-83.56%, and 2.31-74.6%, respectively. The reactive SPR significantly reduced Cd, Pb and Zn leaching while soluble DAP increased their leachate concentrations. The SPR reduced the bioaccumulation of Cd, Pb and Zn in earthworms by 7.13-23.4% and 14.3-54.6% in comparison with earthworms in the DAP and control treatment, respectively. Bioaccessible Cd, Pb and Zn concentrations as determined using a simplified bioaccessibility extraction test showed higher long-term stability of P-immobilized Pb and Zn than Cd. The differential effect of P-induced immobilization between P compounds and metals is due to the variation in the solubility characteristics of P compounds and nature of metal phosphate compounds formed. Therefore, Pb and Zn immobilization by P compounds is an effective long-term remediation strategy for mixed heavy metal contaminated soils.
靶场土壤含有包括铅（Pb）、镉（Cd）和锌（Zn）在内的混合重金属污染物。磷酸盐（P）化合物已被用于固定这些金属，尤其是铅，从而降低其生物有效性。然而，关于铅的共污染物固定化的研究表明了可溶性和不溶性磷化合物的相对重要性，这对于评估原位稳定化实践在混合重金属污染土壤可持续修复中的整体成功至关重要。测试了可溶性合成磷肥（磷酸二铵；DAP）以及活性（塞丘拉；SPR）和非活性（圣诞岛；CPR）天然磷矿石（PR）对镉、铅和锌的固定化作用，以及随后它们在靶场土壤中的迁移性和生物有效性。添加磷化合物分别使镉、铅和锌的固定率达到1.56% - 76.2%、3.21% - 83.56%和2.31% - 74.6%。活性SPR显著降低了镉、铅和锌的淋溶，而可溶性DAP增加了它们的渗滤液浓度。与DAP处理和对照处理中的蚯蚓相比，SPR使蚯蚓体内镉、铅和锌的生物积累分别减少了7.13% - 23.4%和14.3% - 54.6%。使用简化生物可及性提取试验测定的生物可及性镉、铅和锌浓度表明，磷固定的铅和锌比镉具有更高的长期稳定性。磷化合物和金属之间磷诱导固定化的差异效应是由于磷化合物的溶解度特性和形成的金属磷酸盐化合物的性质不同。因此，磷化合物对铅和锌的固定化是混合重金属污染土壤的一种有效的长期修复策略。
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