Role of dissolved organic matter, nitrate, and bicarbonate in the photolysis of aqueous fipronil
Role of dissolved organic matter, nitrate, and bicarbonate in the photolysis of aqueous fipronil
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DOI：
10.1021/es0349047
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发表时间：
2004-07-15
影响因子：
11.4
通讯作者：
Ferry, JL
中科院分区：
文献类型：
--
作者：
Walse, SS;Morgan, SL;Ferry, JL
开发了一个氟虫腈水溶液光降解的多变量动力学模型，该模型是溶解有机物（DOM）、碳酸氢盐和硝酸盐浓度的函数，这些浓度涵盖了天然沃茨中常见的浓度（约100 mg/L）。0-10 mg/L）的浓度下进行。在该系统中，氟虫腈的光降解有几种途径，包括直接光解和自然沃茨光照过程中产生的物种的间接光氧化（例如，（NOM）-N-3*，O-1（2）*，（OH）-O-.，（CO31-）-C-，（OOR）-O-.，（OOH）-O-，e（aq）（-），O-2（.-））。产品研究表明，氟虫腈在数量上转化为氟虫腈双烯虫酰，这是一种仅与直接光解有关的产品。DOM是影响氟虫腈降解的唯一变量;它主要通过竞争性光吸收（即，衰减）和氟虫腈 * 的淬灭。与不含氯化钠的等效实验相比，添加氯化钠（30份/千份）导致氟虫腈损失速度更快（约20%），这意味着氟虫腈在海洋环境中可能更不耐光。
A multivariate kinetic model of aqueous fipronil photodegradation was developed as a function of dissolved organic matter (DOM), bicarbonate, and nitrate at concentrations that bracket those commonly observed in natural waters (ca. 0-10 mg/L). Several pathways were available for fipronil photodegradation in this system, including direct photolysis and indirect photooxidation by species produced during the illumination of natural waters (e.g., (NOM)-N-3*, O-1(2)*, (OH)-O-., (CO31-)-C-., (OOR)-O-., (OOH)-O-., e(aq)(-), O-2(.-)). Product studies indicated that fipronil was quantitatively converted to fipronil desulfinyl, a product that is associated with direct photolysis alone. DOM was the only variable that affected fipronil degradation; it decreased the rate of fipronil photodegradation primarily through competitive light absorption (i.e., attenuation) and the quenching of fipronil*. The addition of sodium chloride (30parts per thousand) resulted in a more rapid rate (similar to20%) of fipronil loss in comparison to equivalent experiments performed without sodium chloride, implying that fipronil may be more photolabile in marine environments.