State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, People's Republic of China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, People's Republic of China.
J Hazard Mater. 2017 Oct 5;339:256-263. doi: 10.1016/j.jhazmat.2017.06.040. Epub 2017 Jun 21.
Hand-to-mouth activity is an important pathway for children's exposure to contaminated soils, which is often co-contaminated by Pb and As in mining and smelting sites. To reduce soil Pb risk to humans by oral exposure, phosphate amendments have been used to reduce Pb relative bioavailability (RBA), but its efficiency has not been investigated using validated in vitro assays nor its influence on As-RBA. Here, 5 contaminated soils (A-E) were amended with 0.5% phosphoric acid (PA) to study its effect on Pb- and As- RBA using a newly-developed mouse kidney model and bioaccessibility using 4 in vitro assays including UBM, SBRC, IVG, and PBET. Based on the mouse kidney model, Pb-RBA in PA-amended soils decreased from 14.2-62.5% to 10.1-29.8%. In contrast, As-RBA decreased from 26.5% to 15.9% in soil B but increased from 27.5 to 41.2% in soil D, with changes being insignificant in 3 other soils (35.8-58.8 to 28.1-61.1%). When assessing Pb bioaccessibility in PA-amended soils, decreased bioaccessibility were found using PBET and SBRC. For As, its bioaccessibility increased in PA-amended soils, inconsistent with in vivo data. Our results shed light on the importance of method selection to assess risk in Pb- and As-contaminated soils amended with phosphate.
手口活动是儿童接触受污染土壤的重要途径，而采矿和冶炼场的土壤往往同时受到 Pb 和 As 的污染。为了通过口服暴露降低土壤 Pb 对人类的风险，已经使用了磷酸盐来降低 Pb 的相对生物可利用性（RBA），但尚未使用经过验证的体外测定来研究其效率，也没有研究其对 As-RBA 的影响。在这里，使用 0.5%的磷酸（PA）对 5 种受污染土壤（A-E）进行了改良，使用新开发的小鼠肾模型研究了其对 Pb 和 As-RBA 的影响，并使用 4 种体外测定方法（UBM、SBRC、IVG 和 PBET）研究了生物可利用性。基于小鼠肾模型，PA 改良土壤中 Pb-RBA 从 14.2%-62.5%降低至 10.1%-29.8%。相比之下，土壤 B 中的 As-RBA 从 26.5%降低至 15.9%，但在土壤 D 中从 27.5%增加至 41.2%，而其他 3 种土壤（35.8%-58.8%至 28.1%-61.1%）的变化不显著。在评估 PA 改良土壤中 Pb 的生物可利用性时，发现使用 PBET 和 SBRC 后生物可利用性降低。对于 As，其在 PA 改良土壤中的生物可利用性增加，与体内数据不一致。我们的研究结果阐明了在受 Pb 和 As 污染的土壤中添加磷酸盐时选择方法评估风险的重要性。
