Reductive transformation of dioxins: An assessment of the contribution of dissolved organic matter to dechlorination reactions
Reductive transformation of dioxins: An assessment of the contribution of dissolved organic matter to dechlorination reactions
复制标题
二恶英的还原转化： 评估溶解有机物对脱氯反应的贡献
DOI：
10.1021/es981342w
复制
发表时间：
1999-11-01
影响因子：
11.4
通讯作者：
Adriaens, P
中科院分区：
文献类型：
--
作者：
Fu, QS;Barkovskii, AL;Adriaens, P
以1，2，3，4，6，7，9-七氯二苯并二恶英（HpCDD）、奥德里奇腐殖酸（AHA）和聚马来酸（PMA）为模型化合物，研究了二恶英对溶解有机碳（DOC）介导的脱氯反应的敏感性.脱氯产率约为4-20%，当归一化为酚酸时，与腐殖成分儿茶酚和间苯二酚存在下观察到的产率相当。根据;关于脱氯率与酚酸酸度和电子转移能力的函数关系，电子转移效率与二恶英的差异可能是与官能团的特异性相互作用和非特异性疏水相互作用的综合效应。Hexa-and pentaCDD同系物在所有孵育中占主导地位，diCDD构成脱氯的最终产物。较少氯化产物的出现率（pM-nM/d）与沉积物系统中观察到的相似，并遵循热力学考虑，因为它们随着氯化水平的降低而降低。一般来说，绝对和酚酸标准化的速率常数AHA介导的反应是高达2倍以上的PMA的影响。这些结果表明，沉积物DOC的电子穿梭能力可能会显着影响二恶英的命运，部分通过脱氯反应。
The susceptibility of dioxins to dissolved organic carbon (DOC)-mediated dechlorination reactions was investigated using 1,2,3,4,6,7,9-heptachlorodibenzo-p-dioxin (HpCDD), Aldrich humic acid (AHA), and polymaleic acid (PMA) as model compounds. The dechlorination yields were on the order of 4-20% which, when normalized to phenolic acidity, was comparable to yields observed in the presence of the humic constituents catechol and resorcinol. Based; on the ratio of dechlorination yields as a function of phenolic acidity and electron transfer capacity, differences in electron transfer efficiency to dioxins a re likely combined effects of specific interactions with the functional groups and nonspecific hydrophobic interactions. Hexa-and pentaCDD homologues were dominant in all incubations, and diCDD constituted the final product of dechlorination. The rates of appearance of lesser chlorinated products (pM-nM/d) were similar to those observed in sediment systems and followed thermodynamic considerations as they decreased with a decrease in level of chlorination. Generally, both absolute and phenolic acidity-normalized rate constants for AHA-mediated reactions were up to 2-fold higher than those effected by PMA. These results indicate that the electron shuttling capacity of sediment DOC may significantly affect the fate of dioxins, in part through dechlorination reactions.