Occurrence and fate of the pharmaceutical drug diclofenac in surface waters: Rapid photodegradation in a lake
Occurrence and fate of the pharmaceutical drug diclofenac in surface waters: Rapid photodegradation in a lake
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DOI：
10.1021/es980301x
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发表时间：
1998-11-15
影响因子：
11.4
通讯作者：
Muller, MD
中科院分区：
文献类型：
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作者：
Buser, HR;Poiger, T;Muller, MD
在瑞士的河流和湖泊中检出了药物双氯芬酸(2-[(2，6-二氯苯基)氨基]苯乙酸)。这些数据强烈表明，双氯芬酸是通过废水处理厂从人类医疗用途中输入的。有趣的是，一个湖泊的主要支流(格雷芬湖)的浓度(高达370毫微克/L)显著高于该湖流出水的浓度(高达12毫微克/L)。据估计，进入湖中的双氯芬酸有90%以上是在湖中消除的，很可能是通过光解降解。在湖泊的沉积物中没有检测到双氯芬酸，在实验室实验中，它在沉积物颗粒上的吸附可以忽略不计。用双氯芬酸强化的湖水孵化在黑暗中没有降解，这表明化学和生物降解很少。然而，当强化水暴露在阳光下时，观察到快速光降解符合(伪)一级动力学，半衰期不到1h(10月和北纬47度)。根据格雷芬塞的情况对这些实验数据进行了建模，数据表明，光降解可以解释双氯芬酸在湖泊中的快速消除。几种光产物在实验室实验中得到了表征，但到目前为止还没有在湖里的自然条件下检测到。虽然光降解往往是环境污染物的几种降解途径之一，但光解实验和计算机模拟表明，这一过程是双氯芬酸在湖泊中的主要降解途径。
The pharmaceutical drug diclofenac (2-[(2,6-dichlorophenyl)amino]benzeneacetic acid) was detected in rivers and lakes in Switzerland. The data strongly suggest inputs of diclofenac from human medical use via wastewater treatment plants. Interestingly, the concentrations in a major tributary to a lake (Greifensee) were significantly higher (up to 370 ng/L) than those in the outflow of this lake (up to 12 ng/L). It is estimated that more than 90% of the diclofenac entering the lake is eliminated in the lake, most likely by photolytic degradation. Diclofenac was not detected in the sediments of the lake, and in a laboratory experiment, it showed negligible adsorption onto sediment particles. Incubation of lake water, fortified with diclofenac, showed no degradation in the dark, suggesting minimal chemical and biological degradation. However, when the fortified water was exposed to sunlight, rapid photodegradation was observed with a (pseudo) first-order kinetic and a half-life of less than 1 h (October and 47 degrees N latitude). Modeling these experimental data for the situation of Greifensee, the data indicated that photodegradation can account for the rapid elimination of diclofenac in the lake. Several photoproducts were characterized in the laboratory experiments but were so far not detected under the natural conditions in the lake. Whereas photodegradation is often one among several degradation pathways for environmental contaminants, the photolysis experiments and the computer simulation suggested this process to be the predominant one for diclofenac in the lake.