Università di Torino, Dipartimento di Chimica, Via Pietro Giuria 5, 10125 Torino, Italy; Università di Torino, Centro Interdipartimentale NatRisk, Largo Paolo Braccini 2, 10095 Grugliasco TO, Italy.
FCC Aqualia S.A., C/ Montesinos 28, 06002, Badajoz, Spain.
Chemosphere. 2018 May;198:473-481. doi: 10.1016/j.chemosphere.2018.01.156. Epub 2018 Feb 3.
We predicted the possible direct and indirect phototransformation kinetics of carbamazepine (CBZ), ibuprofen (IBU) and diclofenac (DIC) in river water, based on data of water chemistry obtained for the Guadiana River near Badajoz (Southwestern Spain) during a year-round sampling campaign. The three compounds were chosen, (i) because they occurred at the outlet of the wastewater treatment plant (WWTP) in Badajoz, as well as in river water sampled 1 km downstream of the WWTP, and (ii) because their photochemical fate in surface waters is known well enough to be modelled. The predicted phototransformation kinetics would be negligible in winter and fastest in April-August, with comparable rate constants in April through August despite differences in sunlight irradiance. Favourable water chemistry would in fact offset the lower irradiance, and vice versa. Half-life times of at least three weeks - one month are predicted for CBZ and IBU. Photodegradation may be an important attenuation pathway for biorecalcitrant CBZ, while IBU photochemistry is unlikely to be competitive with other processes including biodegradation. The predicted DIC photochemical half-life times of 7-10 days in April-August would be comparable with the biodegradation kinetics data reported in the literature. Photochemistry might not induce extensive phototransformation of xenobiotics in the Guadiana River under normal flow conditions, but it could become important in the case of low flow produced by water scarcity.
我们预测了卡马西平（CBZ）、布洛芬（IBU）和双氯芬酸（DIC）在瓜迪亚纳河水中可能的直接和间接光转化动力学，该数据基于在西班牙巴达霍斯附近的瓜迪亚纳河进行的全年采样活动中获得的水化学数据。选择这三种化合物，（i）是因为它们出现在巴达霍斯污水处理厂（WWTP）的出水口，以及在 WWTP 下游 1 公里处采集的河水中，（ii）是因为它们在地表水中的光化学命运已经足够了解，可以进行建模。预测的光转化动力学在冬季可忽略不计，在 4 月至 8 月最快，尽管阳光辐照度存在差异，但 4 月至 8 月的速率常数相当。实际上，有利的水化学会抵消较低的辐照度，反之亦然。预计 CBZ 和 IBU 的半衰期至少为三周 - 一个月。光降解可能是生物难降解 CBZ 的重要衰减途径，而 IBU 的光化学不太可能与包括生物降解在内的其他过程竞争。预测的 DIC 在 4 月至 8 月的光化学半衰期为 7-10 天，与文献中报道的生物降解动力学数据相当。在正常流量条件下，光化学可能不会导致瓜迪亚纳河中外来污染物的广泛光转化，但在缺水导致流量低的情况下，它可能变得很重要。
