title: Isomer-specific degradation of branched and linear 4-nonylphenol isomers in an oxic soil.
abstract: Using (14)C- and (13)C-ring-labeling, degradation of five p-nonylphenol (4-NP) isomers including four branched (4-NP(38), 4-NP(65), 4-NP(111), and 4-NP(112)) and one linear (4-NP(1)) isomers in a rice paddy soil was studied under oxic conditions. Degradation followed an availability-adjusted first-order kinetics with the decreasing order of half-life 4-NP(111) (10.3 days) > 4-NP(112) (8.4 days) > 4-NP(65) (5.8 days) > 4-NP(38) (2.1 days) > 4-NP(1) (1.4 days), which is in agreement with the order of their reported estrogenicities. One metabolite of 4-NP(111) with less polarity than the parent compound occurred rapidly and remained stable in the soil. At the end of incubation (58 days), bound residues of 4-NP(111) amounted to 54% of the initially applied radioactivity and resided almost exclusively in the humin fraction of soil organic matter, in which chemically humin-bound residues increased over incubation. Our results indicate an increase of specific estrogenicity of the remaining 4-NPs in soil as a result of the isomer-specific degradation and therefore underline the importance of understanding the individual fate (including degradation, metabolism, and bound-residue formation) of isomers for risk assessment of 4-NPs in soil. 4-NP(1) should not be used as a representative of 4-NPs for studies on their environmental behavior.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University , 163 Xianlin Avenue, 210046 Nanjing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Shan
authors.forename: Bingqi
authors.initials: B
authors.lastname: Jiang
authors.forename: Bin
authors.initials: B
authors.lastname: Yu
authors.forename: Chengliang
authors.initials: C
authors.lastname: Li
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Sun
authors.forename: Hongyan
authors.initials: H
authors.lastname: Guo
authors.forename: Jichun
authors.initials: J
authors.lastname: Wu
authors.forename: Erwin
authors.initials: E
authors.lastname: Klumpp
authors.forename: Andreas
authors.initials: A
authors.lastname: Schäffer
authors.forename: Rong
authors.initials: R
authors.lastname: Ji
mesh_terms: D002247:Carbon Isotopes; D005591:Chemical Fractionation; D004777:Environment; D006812:Humic Substances / Q000032:analysis; D007536:Isomerism; D007700:Kinetics; D008903:Minerals / Q000737:chemistry; D012275:Oryza; D010100:Oxygen / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D011851:Radioactivity; D012987:Soil / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D006812:Humic Substances; D008903:Minerals; D010636:Phenols; D012987:Soil; C041594:4-nonylphenol; D010100:Oxygen