In Situ Fixation of Metal(loid)s in Contaminated Soils: A Comparison of Conventional, Opportunistic, and Engineered Soil Amendments
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- 作者：Elena Mele ; Erica Donner ; Albert L. Juhasz ; Gianluca Brunetti ; Euan Smith ; Aaron R. Betts ; Paola Castaldi ; Salvatore Deiana ; Kirk G. Scheckel ; Enzo Lombi
- 刊名：Environmental Science & Technology
- 出版年：2015
- 出版时间：November 17, 2015
- 年：2015
- 卷：49
- 期：22
- 页码：13501-13509
- 全文大小：394K
- ISSN：1520-5851
文摘
This study aimed to assess and compare the in vitro and in vivo bioaccessibility/bioavailability of As and Pb in a mining contaminated soil (As, 2267 mg kg鈥?; Pb, 1126 mg kg鈥?), after the addition of conventional (phosphoric acid), opportunistic [water treatment residues (WTRs)], and engineered [nano- and microscale zero valent iron (ZVI)] amendments. Phosphoric acid was the only amendment that could significantly decrease Pb bioaccessibility with respect to untreated soil (41 and 47% in the gastric phase and 2.1 and 8.1% in the intestinal phases, respectively), giving treatment effect ratios (TERs, the bioaccessibility in the amended soil divided by the bioaccessibility in the untreated soil) of 0.25 and 0.87 in the gastric and intestinal phase, respectively. The in vivo bioavailability of Pb decreased in the phosphate treatment relative to the untreated soil (6 and 24%, respectively), and also in the Fe WTR 2% (12%) and nZVI-2 (13%) treatments. The ZVI amendments caused a decrease in As bioaccessibility, with the greatest decrease in the nZVI2-treated soil (TERs of 0.59 and 0.64 in the gastric and intestinal phases, respectively). Arsenic X-ray absorption near-edge spectroscopy analysis indicated that most of the As in the untreated soil was present as As(V) associated with Fe mineral phases, whereas in the treated soil, the proportion of arsenosiderite increased. Arsenite was present only as a minor species (3鈥?%) in the treated soils, with the exception of an nZVI treatment [鈭?4% of As(III)], suggesting a partial reduction of As(V) to As(III) caused by nZVI oxidation.