School of Environment and Natural Resources, 210 Kottman Hall, 2021 Coffey Road, The Ohio State University, Columbus, OH 43210, United States.
U.S. Environmental Protection Agency, National Risk Management Research Laboratory, Land Remediation and Pollution Control Division, Cincinnati, OH 45224-1701, United States.
Environ Pollut. 2017 Jan;220(Pt A):549-556. doi: 10.1016/j.envpol.2016.10.002. Epub 2016 Oct 14.
Lead (Pb) contaminated soils are a potential exposure hazard to the public. Amending soils with phosphorus (P) may reduce Pb soil hazards. Soil from Cleveland, OH containing 726 ± 14 mg Pb kg was amended in a laboratory study with bone meal and triple super phosphate (TSP) at 5:1 P:Pb molar ratios. Soil was acidified, neturalized and re-acidified to encourage Pb phosphate formation. PRSTM-probes were used to evaluate changes in soil solution chemistry. Soil acidification did not decrease in vitro bioaccessible (IVBA) Pb using either a pH 1.5, 0.4 M glycine solution or a pH 2.5 solution with organic acids. PRSTM-probe data found soluble Pb increased 10-fold in acidic conditions compared to circumnetural pH conditions. In acidic conditions (p = 3-4), TSP treated soils increased detected P 10-fold over untreated soils. Bone meal application did not increase PRSTM-probe detected P, indicating there may have been insufficient P to react with Pb. X-ray absorption spectroscopy suggested a 10% increase in pyromorphite formation for the TSP treated soil only. Treatments increased soil electrical conductivity above 16 mS cm, potentially causing a new salinity hazard. This study used a novel approach by combining the human ingestion endpoint, PRSTM-probes, and X-ray absorption spectroscopy to evaluate treatment efficacy. PRSTM-probe data indicated potentially excess Ca relative to P across incubation steps that could have competed with Pb for soluble P. More research is needed to characterize soil solutions in Pb contaminated urban soils to identify where P treatments might be effective and when competing cations, such as Ca, Fe, and Zn may limit low rate P applications for treating Pb soils.
受铅（Pb）污染的土壤对公众构成潜在的暴露危害。用磷（P）改良土壤可能会降低 Pb 土壤危害。在一项实验室研究中，用骨粉和三料过磷酸钙（TSP）以 5:1 的 P:Pb 摩尔比处理了来自俄亥俄州克利夫兰的土壤，该土壤含 726±14mg Pb kg。酸化、中和和再酸化土壤以促进 Pb 磷酸盐的形成。使用 PRSTM 探针评估土壤溶液化学变化。使用 pH 1.5、0.4 M 甘氨酸溶液或 pH 2.5 有机酸溶液，土壤酸化并未降低体外生物可利用性（IVBA）Pb。PRSTM 探针数据发现，与周围 pH 条件相比，在酸性条件下可溶性 Pb 增加了 10 倍。在酸性条件下（p=3-4），TSP 处理土壤中检测到的 P 比未处理土壤增加了 10 倍。骨粉的应用并未增加 PRSTM 探针检测到的 P，表明可能没有足够的 P 与 Pb 反应。X 射线吸收光谱仅表明 TSP 处理土壤中焦磷酸铅的形成增加了 10%。处理使土壤电导率增加到 16 mS cm 以上，可能会造成新的盐度危害。本研究采用了一种新方法，将人类摄入终点、PRSTM 探针和 X 射线吸收光谱相结合，评估处理效果。PRSTM 探针数据表明，在整个孵育过程中，潜在的 Ca 相对于 P 过量，这可能会与 Pb 竞争可溶性 P。需要进一步研究受 Pb 污染的城市土壤的土壤溶液，以确定 P 处理在何处可能有效，以及在哪些情况下，Ca、Fe 和 Zn 等竞争阳离子可能会限制低速率 P 应用于处理 Pb 土壤。
