title: Uptake Pathway, Translocation, and Isomerization of Hexabromocyclododecane Diastereoisomers by Wheat in Closed Chambers.
abstract: To study the uptake pathways of 3 main hexabromocyclododecane diastereoisomers (α-, β-, and γ-HBCDs) in wheat, four closed chambers were designed to expose wheat to HBCDs via air and/or soil for 4 weeks. The results showed that HBCDs could be absorbed by wheat both via root from soil and via leaf from air. The Rt values (ratio of HBCDs from root-to-leaf translocation to the total accumulation in leaves) ranging from 14.4 to 29.8% suggested that acropetal translocation within wheat was limited. A negative linear relationship was found between log Rt and log Kow of the HBCD diastereoisomers (p < 0.05). The bioconcentration factors (BCFs, (μg/g wheat tissues)/(μg/g soil)) were in the order α- > β- > γ-HBCD in wheat roots and stems, being negatively related to their Kow values. No such correlation was found in leaves, where the HBCDs came mainly from air distribution. The results of enantiomeric fractions indicated that the (-)-enantiomer of α- and γ-HBCDs and the (+)-β-enantiomer were selectively accumulated. Furthermore, β- and γ-HBCDs were transformed to α-HBCD in the wheat, with 0.309-4.80% and 0.920-8.40% bioisomerization efficiencies at the end of the experiment, respectively, being the highest in leaves. Additionally, no isomerization product from α-HBCD was found.
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University , Tianjin 300071, China.
authors.forename: Hongkai
authors.initials: H
authors.lastname: Zhu
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University , Tianjin 300071, China.
authors.forename: Hongwen
authors.initials: H
authors.lastname: Sun
authors.affiliation: Agro-Environmental Protection Institute , Ministry of Agriculture, Tianjin 300191, China.
authors.forename: Yanwei
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University , Tianjin 300071, China.
authors.forename: Jiayao
authors.initials: J
authors.lastname: Xu
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University , Tianjin 300071, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.affiliation: MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University , Tianjin 300071, China.
authors.forename: Qixing
authors.initials: Q
authors.lastname: Zhou
mesh_terms: D001692:Biological Transport; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D006842:Hydrocarbons, Brominated / Q000378:metabolism / Q000493:pharmacokinetics*; D007536:Isomerism; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D012987:Soil; D012989:Soil Pollutants / Q000378:metabolism / Q000493:pharmacokinetics*; D013237:Stereoisomerism; D014908:Triticum / Q000378:metabolism*
chemical_list: D006842:Hydrocarbons, Brominated; D012987:Soil; D012989:Soil Pollutants; C089796:hexabromocyclododecane