中文摘要：

研究了腐植酸（HA）存在下冰相体系中γ-六氯环己烷（γ-HCH）的光转化规律.结果表明,HA浓度对γ-HCH的光转化率呈现低浓度促进而高浓度抑制的现象;盐离子浓度、NO2-及NO3-对γ-HCH的光转化率均有促进作用;低浓度Fe3＋对γ-HCH的光转化率有促进作用,当Fe3＋的浓度增大到50μmol/L时,呈现抑制效应;γ-HCH在不同p H值条件下光转化速率的大小顺序为碱性〉中性〉酸性.冰相中HA通过产生单线态氧（1O2）、羟基自由基（·OH）及三重激发态（HA＊）加速γ-HCH的光转化.HA存在下γ-HCH的光转化产物主要是五氯环己烯、邻二氯苯和对二氯苯、一氯苯,光转化过程中1O2通过消耗中间产物间接加速了γ-HCH的光转化过程.

英文摘要：

The photoconversion regularity of γ-hexachlorocyclohexane（γ-HCH） in snow and ice in the presence of humic acid（HA） were studied. The results showed that the photoconversion efficiency of γ-HCH was promoted at low initial concentration of HA,but inhibited at high concentration of HA. Salt ion concentration,NO2-and NO3-all promoted the photoconversion efficiency of γ-HCH. The photoconversion efficiency ofγ-HCH was promoted at low initial concentration of Fe3＋,but inhibited when the concentration of Fe3＋reached50 μmol/L. The sequence of photoconversion rate of γ-HCH at different p H was alkalineneutralacidic. HA accelerated the photoconversion of γ-HCH by producing singlet oxygen（1O2）,hydroxyl free radical（·OH）and triple excited state（HA＊） in ice. Photoproducts of γ-HCH in the presence of HA are mainly pentachlorocyclohexene,p-dichlorobenzene and o-dichlorobenzene,1-chlorobenzene,and1O2 indirectly accelerated the photoconversion of γ-HCH by consuming the intermediate products.