Enrichment and solubility of trace metals associated with magnetic extracts in industrially derived contaminated soils.
Magnetic fractions (MFs) in industrially derived contaminated soils were extracted with a magnetic separation procedure. Total, soluble, and bioaccessible Cr, Cu, Pb and Zn in the MFs and non-magnetic fractions (NMFs) were analyzed using aqua regia and extraction tests, such as deionized water, toxicity characteristic leaching procedure (TCLP), and gastric juice simulation (GJST) test. Compared with the non-magnetic fractions, soil MFs were enriched with Fe, Mn, Pb, Cd, Cr, Cu, and Ni. Extraction tests indicated that soil MFs contained higher water, TCLP, and GJST-extractable Cr, Cu, Pb, and Zn concentrations than the soil NMFs. The TCLP-extractable Pb concentration in the MFs exceeded the USEPA hazardous waste criteria, suggesting that soil MFs have a potentially environmental pollution risk. Solubility of trace metals was variable in the different extraction tests, which has the order of GJST > TCLP > water. TCLP test showed Cu and Zn were more mobile than Cr and Pb while bioaccessibility of trace metal defined by GJST test showed the order of Cu ≈ Cr ≈ Zn > Pb. These findings suggested that the MFs in the industrially derived contaminated soils had higher possibility of polluting water bodies, and careful environmental impact assessment was necessary.
Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China. lusg@zju.edu.cn
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D000818:Animals; D002681:China; D005750:Gastric Juice / Q000378:metabolism; D006801:Humans; D059346:Magnets / Q000737:chemistry; D008670:Metals / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D008855:Microscopy, Electron, Scanning; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D012995:Solubility; D013052:Spectrometry, X-Ray Emission; D014131:Trace Elements / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity
D008670:Metals; D012989:Soil Pollutants; D014131:Trace Elements