Chlorpyrifos Transformation by Aqueous Chlorine in the Presence of Bromide and Natural Organic Matter

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• 作者：Stephen E. Duirk ; J. Christopher Tarr ; Timothy W. Collette
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2008
• 出版时间：February 27, 2008
• 年：2008
• 卷：56
• 期：4
• 页码：1328 - 1335
• 全文大小：184K
• 年卷期：v.56,no.4(February 27, 2008)
• ISSN：1520-5118

文摘

The aqueous chlorination of chlorpyrifos (CP) was investigated in the presence of bromide and natural organic matter (NOM), which were identified as naturally occurring aqueous constituents that could affect CP transformation rates to the toxic product chlorpyrifos oxon (CPO). Bromide can be oxidized by chlorine to form hypobromous acid (HOBr), which was found to oxidize CP at a rate that was 3 orders of magnitude faster than was the case with chlorine: k_HOBr,CP = 1.14 (± 0.21) × 10⁹ M⁻¹ h⁻¹ and k_HOCl,CP = 1.72 × 10⁶ M⁻¹ h⁻¹, respectively. Similar to previous findings with the hypochlorite ion, hypobromite (OBr⁻) was found to accelerate the hydrolysis of CP and CPO: k_OBr,CP = 965 (± 110) M⁻¹ h⁻¹ and k_OBr,CPO = 1390 (± 160) M⁻¹ h⁻¹, respectively. Treated water from the Athens-Clarke County (ACC) water treatment plant in Athens, GA, was used in some of the experiments as a NOM source. A mechanistic model was used to adequately predict the loss of CP as well as the formation of CPO and the hydrolysis product 3,5,6-trichloro-2-pyridinol (TCP) in the presence of the ACC water.