Zhan Manjun
Nanjing Research Institute of Environmental Protection, Nanjing 210013, China.
J Environ Sci (China). 2009;21(3):303-6. doi: 10.1016/s1001-0742(08)62268-8.
Reactive oxygen species (ROS) can be produced by interactions between sunlight and light-absorbing substances in natural water environment. ROS may participate in the indirect photolysis of trace organic pollutants, therefore resulting in changes in their environmental fates and ecological risks in natural water systems. Bisphenol A (BPA), an endocrine-disrupting chemical, exits widely in natural waters. The photodegradation of BPA promoted by ROS (OH, 1O2, HO2/O2(*-)), which were produced on the excitation of ubiquitous constituents (such as nitrate ion, humic substances and Fe(III)-oxalate complexes) in natural water under simulated solar radiation was investigated. Both molecular probe method and electron spin resonance (ESR) test were used for the characterization of the generated ROS. It was found that *OH was photochemically produced in the presence of nitrate ions, humic substances and Fe(III)-oxalate complexes and that 102 was produced with the presence of humic substances. The steady-state concentrations of *OH was 1.27x10(-14) mol/L in a nitrate solution, and the second-order rate constant of BPA with *OH was 1.01 x 10(10) L/(mol x s).
活性氧（ROS）可通过自然水环境中阳光与光吸收物质之间的相互作用产生。ROS可能参与微量有机污染物的间接光解，从而导致其在天然水系统中的环境归宿和生态风险发生变化。双酚A（BPA）是一种内分泌干扰化学物质，广泛存在于天然水体中。研究了在模拟太阳辐射下，天然水中普遍存在的成分（如硝酸根离子、腐殖质和铁（III）-草酸盐络合物）激发产生的ROS（OH、¹O₂、HO₂⁻/O₂⁻）对BPA光降解的促进作用。采用分子探针法和电子自旋共振（ESR）测试对生成的ROS进行表征。研究发现，在硝酸根离子、腐殖质和铁（III）-草酸盐络合物存在下可光化学产生OH，在腐殖质存在下可产生¹O₂。在硝酸盐溶液中，OH的稳态浓度为1.27×10⁻¹⁴ mol/L，BPA与OH的二级反应速率常数为1.01×10¹⁰ L/（mol·s）。
