Modeling the Photochemical Attenuation of Down-the-Drain Chemicals during River Transport by Stochastic Methods and Field Measurements of Pharmaceuticals and Personal Care Products
Modeling the Photochemical Attenuation of Down-the-Drain Chemicals during River Transport by Stochastic Methods and Field Measurements of Pharmaceuticals and Personal Care Products
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DOI：
10.1021/es4035478
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发表时间：
2013-12-03
影响因子：
11.4
通讯作者：
Tanaka, Hiroaki
中科院分区：
文献类型：
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作者：
Hanamoto, Seiya;Nakada, Norihide;Tanaka, Hiroaki
现有的用于预测水环境中向下排放的化学物质浓度的随机模型没有考虑到阳光直接光解的日变化，尽管它是自然衰减的一个重要因素。为了克服这一局限，我们开发了一个包含直接光解过程中时间变化的随机模型。为了验证模型，我们在一条7.6公里长的城市河流中测量了57种药品和个人护理产品(PPCP)，并在实验室实验中确定了它们的物理和生物特性。在沿河运输过程中，包括酮洛芬和阿奇霉素在内的8种PPCP被衰减20%，主要是由于直接光解和吸附在沉积物上。耐光性的PPCP在白天显著减弱，但在夜间持续。观察到的结果与光解模型对耐光性多氯联苯(即酮洛芬、双氯芬酸和速尿)的预测值相似，但与现有模型预测的值不同。本研究所建立的随机模型是一种新的、实用的随机模型，可以用来评价河流运输过程中排放的化学物质的直接光解。
Existing stochastic models for predicting concentrations of down-the-drain chemicals in aquatic environments do not account for the diurnal variation of direct photolysis by sunlight, despite its being an important factor in natural attenuation. To overcome this limitation, we developed a stochastic model incorporating temporal variations in direct photolysis. To verify the model, we measured 57 pharmaceuticals and personal care products (PPCPs) in a 7.6-km stretch of an urban river, and determined their physical and biological properties in laboratory experiments. During transport along the river, 8 PPCPs, including ketoprofen and azithromycin, were attenuated by >20%, mainly owing to direct photolysis and adsorption to sediments. The photolabile PPCPs attenuated significantly in the daytime but persisted in the nighttime. The observations were similar to the values predicted by the photolysis model for the photolabile PPCPs (i.e., ketoprofen, diclofenac and furosemide) but not by the existing model. The stochastic model developed in this study was suggested to be a novel and useful stochastic model for evaluating direct photolysis of down-the-drain chemicals, which occurs during the river transport.