School of Environmental and Chemical Engineering, Shanghai University, 99 Shangda Road, Shanghai, 200444, China.
Environ Sci Pollut Res Int. 2020 Jun;27(17):20807-20816. doi: 10.1007/s11356-020-08500-1. Epub 2020 Apr 4.
The occurrence of anticancer drugs in the environment has attracted wide attention due to its potential environmental risks. The aim of this study was to investigate degradation characteristics and mechanism of anticancer drug capecitabine (CPC) by electron beam (EB) irradiation. The results showed that EB was an efficient water treatment process for CPC. The degradation followed pseudo-first-order kinetics with dose constants ranged from 1.27 to 3.94 kGy. Removal efficiencies in natural water filtered or unfiltered were lower than pure water due to the effect of water matrix components. The degradation was restrained by the presence of NO, NO and CO, and fulvic acid due to competition of reactive radical •OH. It demonstrated that oxidizing radical played important role in irradiation process. The appropriate addition of HO and KSO providing with oxidizing agents •OH and •SO was favorable to improve degradation efficiency of CPC. The possible transformation pathways of CPC including cleavage of the ribofuranose sugar and defluorination were proposed based on intermediate products and were consistent with the theoretical calculation of charge and electron density distribution. Toxicity of CPC and intermediate products were estimated by ECOSAR program. It was found that CPC was transformed to low toxicity products with EB.
由于其潜在的环境风险，抗癌药物在环境中的出现引起了广泛关注。本研究旨在探讨电子束（EB）辐照下抗癌药物卡培他滨（CPC）的降解特性和机制。结果表明，EB 是一种有效的 CPC 水处理工艺。降解遵循准一级动力学，剂量常数范围为 1.27 至 3.94 kGy。由于水基质成分的影响，过滤或未过滤的天然水中的去除效率低于纯水。由于反应性自由基 •OH 的竞争，存在 NO、NO 和 CO 以及富里酸会抑制降解。这表明氧化自由基在辐照过程中起重要作用。适当添加 HO 和 KSO 提供氧化剂 •OH 和 •SO 有利于提高 CPC 的降解效率。基于中间产物提出了 CPC 的可能转化途径，包括核糖呋喃糖的裂解和脱氟，这与电荷和电子密度分布的理论计算一致。通过 ECOSAR 程序评估了 CPC 和中间产物的毒性。结果发现，EB 可将 CPC 转化为低毒性产物。
