title: Phytoavailability and mechanism of bound PAH residues in filed contaminated soils.
abstract: Understanding the phytoavailability of bound residues of polycyclic aromatic hydrocarbons (PAHs) in soils is essential to assessing their environmental fate and risks. This study investigated the release and plant uptake of bound PAH residues (reference to parent compounds) in field contaminated soils after the removal of extractable PAH fractions. Plant pot experiments were performed in a greenhouse using ryegrass (Lolium multiflorum Lam.) to examine the phytoavailablility of bound PAH residues, and microcosm incubation experiments with and without the addition of artificial root exudates (AREs) or oxalic acid were conducted to examine the effect of root exudates on the release of bound PAH residues. PAH accumulation in the ryegrass after a 50-day growth period indicated that bound PAH residues were significantly phytoavailable. The extractable fractions, including the desorbing and non-desorbing fractions, dominated the total PAH concentrations in vegetated soils after 50 days, indicating the transfer of bound PAH residues to the extractable fractions. This transfer was facilitated by root exudates. The addition of AREs and oxalic acid to test soils enhanced the release of bound PAH residues into their extractable fractions, resulting in enhanced phytoavailability of bound PAH residues in soils. This study provided important information regarding environmental fate and risks of bound PAH residues in soils.
authors.affiliation: Institute of Organic Contaminant Control and Soil Remediation, College of Resource and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China. Electronic address: gaoyanzheng@njau.edu.cn.
authors.forename: Yanzheng
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Institute of Organic Contaminant Control and Soil Remediation, College of Resource and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Hu
authors.affiliation: Institute of Organic Contaminant Control and Soil Remediation, College of Resource and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Ziyuan
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Institute of Organic Contaminant Control and Soil Remediation, College of Resource and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Yize
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Organic Contaminant Control and Soil Remediation, College of Resource and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Bingqing
authors.initials: B
authors.lastname: Sun
mesh_terms: D001673:Biodegradation, Environmental; D004787:Environmental Pollution; D008129:Lolium / Q000378:metabolism*; D019815:Oxalic Acid / Q000737:chemistry / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; D019815:Oxalic Acid
keywords: Bound residue; Organic acid; Phytoavailability; Polycyclic aromatic hydrocarbons; Root exudates