Somasundar Yogesh, Burton Abigail E, Mills Matthew R, Zhang David Z, Ryabov Alexander D, Collins Terrence J
Institute for Green Science, Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA.
iScience. 2020 Dec 7;24(1):101897. doi: 10.1016/j.isci.2020.101897. eCollection 2021 Jan 22.
Oxidative water purification of micropollutants (MPs) can proceed via toxic intermediates calling for procedures for connecting degrading chemical mixtures to evolving toxicity. Herein, we introduce a method for projecting evolving toxicity onto composite changing pollutant and intermediate concentrations illustrated through the TAML/HO mineralization of the common drug and MP, propranolol. The approach consists of identifying the key intermediates along the decomposition pathway (UPLC/GCMS/NMR/UV-Vis), determining for each by simulation and experiment the rate constants for both catalytic and noncatalytic oxidations and converting the resulting predicted concentration versus time profiles to evolving composite toxicity exemplified using zebrafish lethality data. For propranolol, toxicity grows substantially from the outset, even after propranolol is undetectable, echoing that intermediate chemical and toxicity behaviors are key elements of the environmental safety of MP degradation processes. As TAML/HO mimics mechanistically the main steps of peroxidase catalytic cycles, the findings may be relevant to propranolol degradation in environmental waters.
微污染物（MPs）的氧化水净化过程可能会通过有毒中间体进行，这就需要有将降解化学混合物与不断变化的毒性联系起来的程序。在此，我们介绍一种方法，通过常见药物和微污染物普萘洛尔的TAML/HO矿化过程，将不断变化的毒性投射到污染物和中间体浓度不断变化的复合物上。该方法包括沿着分解途径识别关键中间体（超高效液相色谱/气相色谱 - 质谱联用仪/核磁共振仪/紫外 - 可见分光光度计），通过模拟和实验确定每种中间体在催化氧化和非催化氧化中的速率常数，并将由此得到的预测浓度随时间变化的曲线转化为不断变化的复合毒性，以斑马鱼致死率数据为例进行说明。对于普萘洛尔，即使在检测不到普萘洛尔之后，毒性从一开始就大幅增加，这反映出中间体的化学和毒性行为是微污染物降解过程环境安全性的关键因素。由于TAML/HO在机理上模拟了过氧化物酶催化循环的主要步骤，这些发现可能与环境水体中普萘洛尔的降解有关。
