中文摘要：

以三氯牛（TCS）为目标化合物，考察了Nordic湖腐植酸（NLHA）及Nordic湖富里酸（NLFA）对TCS光化学行为的影响，并初步探讨了溶解性有机质（DOM）对TCS光降解的影响机制。结果表明，2种DOM均显著抑制TCS的光解，NLFA及NLHA分别使TCS的光解半减期从103min延长至116和165min通过比较理论光屏蔽系数和实验获得的表观光屏蔽系数发现，对于NLFA，其抑制TCS的光解主要以光屏蔽作和为主。但是，NLHA除光屏蔽作用外，还存往其他影响机制。通过透析实验测试了NLFA和NLHA与TCS的结合常数（10gKDOC）分别为2．81和4．60，并计算了TCS的形态分布，在NLFA存在时，TCS主要以游离态存在，而NLHA存在时，16．6％的TCS以结合态存在。通过动/静态淬灭计算分析表明，除光屏蔽作用以外，NLHA可能通过动态淬灭抑制TCS的光解。

英文摘要：

Effects of two dissolved organic matters （DOM） including Nordic Lake fulvic acid （NLFA） and Nordic Lake hu- mic acid （NLHA） on the photolysis of TCS were studied. Results showed that the presence of NLFA and NLHA extends the half life time of TCS from 103 rain to 116 min and 165 min respectively. According to comparison of predicted and observed light screening factor, it was found that light screening effect successfully accounts for inhibition of the photolysis of TCS in the presence of NLFA, while there is other mechanism for NLHA except for light screening effect. To study the speciation of TCS, the association constants of TCS with the two DOM were measured using dialysis technique, with association constants of TCS as 2.81 and 4.60 for NLFA and NLHA. Free TCS is dominant in the presence of NLFA, while 16.6% of TCS is binding with NLHA. The predicted photolysis rate of free TCS is larger than the observed photolysis rate, which indicates that dynamic quenching also makes a contribution to the inhibition of TCS photolysis, besides light screening effect.