title: Occurrence and speciation of polymeric chromium(III), monomeric chromium(III) and chromium(VI) in environmental samples.
abstract: Laboratory experiments suggest that polymeric Cr(III) could exist in aqueous solution for a relative long period of time. However, the occurrence of polymeric Cr(III) has not been reported in environmental media due partially to the lack of method for speciating polymeric Cr. We observed an unknown Cr species during the course of study on speciation of Cr in the leachates of chromated-copper-arsenate (CCA)-treated wood. Efforts were made to identify structure of the unknown Cr species. Considering the forms of Cr existed in the CCA-treated woods, we mainly focused our efforts to determine if the unknown species were polymeric Cr(III), complex of Cr/As or complex of Cr with dissolved organic matter (DOM). In order to evaluate whether polymeric Cr(III) largely exist in wood leachates, high performance liquid chromatography coupled with inductively coupled mass spectrometry (HPLC-ICPMS was used) for simultaneous speciation of monomeric Cr(III), polymeric Cr(III), and Cr(VI). In addition to wood leachates where polymeric Cr (III) ranged from 39.1 to 67.4%, occurrence of the unknown Cr species in other environmental matrices, including surface waters, tap and waste waters, was also investigated. It was found that polymeric Cr(III) could exist in environmental samples containing μg/L level of Cr, at a level up to 60% of total Cr, suggesting that polymeric Cr(III) could significantly exist in natural environments. Failure in quantifying polymeric Cr(III) would lead to the underestimation of total Cr and bias in Cr speciation. The environmental implication of the presence of polymeric Cr(III) species in the environment deserves further study.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; Department of Chemistry & Biochemistry, Florida International University, University Park, Miami, FL 33199, USA. Electronic address: lghu@rcees.ac.cn.
authors.forename: Ligang
authors.initials: L
authors.lastname: Hu
authors.affiliation: Department of Chemistry & Biochemistry, Florida International University, University Park, Miami, FL 33199, USA; Institute of Environment and Health, Jianghan University, Wuhan 430056, China. Electronic address: cai@fiu.edu.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang
mesh_terms: D001149:Arsenates / Q000737:chemistry*; D002274:Carcinogens, Environmental / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D004784:Environmental Monitoring; D013058:Mass Spectrometry / Q000379:methods; D011108:Polymers / Q000032:analysis / Q000737:chemistry; D014934:Wood / Q000737:chemistry*
chemical_list: D001149:Arsenates; D002274:Carcinogens, Environmental; D011108:Polymers; D002857:Chromium; C074702:chromium hexavalent ion; C040890:chromated copper arsenate
keywords: CCA; Chromium speciation; Cr(III); Cr(VI); Polymeric Cr(III)