title: [Effects of Low-Molecular-Weight Organic Acids on the Speciation of Pb in Purple Soil and Soil Solution].
abstract: Lead (Pb) in purple soil was selected as the research target, using one-step extraction method with 0.01 mol · L⁻¹ sodium nitrate as the background electrolyte to study the release effect of citric acid (CA), tartaric acid (TA) and acetic acid (AC) with different concentrations. Sequential extraction and geochemical model (Visual Minteq v3.0) were applied to analyze and predict the speciation of Pb in soil solid phase and soil solution phase. Then the ebvironmental implications and risks of low-molecule weight organic acid (LMWOA) on soil Pb were analyzed. The results indicated that all three types of LMWOA increased the desorption capacity of Pb in purple soil, and the effect followed the descending order of CA > TA > AC. After the action of LMWOAs, the exchangeable Pb increased; the carbonate-bound Pb and Fe-Mn oxide bound Pb dropped in soil solid phase. Organic bound Pb was the main speciation in soil solution phase, accounting for 45.16%-75.05%. The following speciation of Pb in soil solution was free Pb, accounting for 22.71%-50.25%. For CA and TA treatments, free Pb ions and inorganic bound Pb in soil solution increased with increasing LMWOAs concentration, while organic bound Pb suffered a decrease in this process. An opposite trend for AC treatment was observed compared with CA and TA treatments. Overall, LMWOAs boosted the bioavailability of Pb in purple soil and had a potential risk to contaminate underground water. Among the three LMWOAs in this study, CA had the largest potential to activate soil Pb.
authors.forename: Jiang
authors.initials: J
authors.lastname: Liu
authors.forename: Tao
authors.initials: T
authors.lastname: Jiang
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
authors.forename: Jin-zhong
authors.initials: JZ
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
mesh_terms: D019342:Acetic Acid / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry*; D007854:Lead / Q000737:chemistry*; D008970:Molecular Weight; D009566:Nitrates; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry; D012996:Solutions; D013644:Tartrates / Q000737:chemistry*
chemical_list: D009566:Nitrates; D012987:Soil; D012989:Soil Pollutants; D012996:Solutions; D013644:Tartrates; D019343:Citric Acid; D007854:Lead; D019342:Acetic Acid; C029768:tartaric acid