Department of Chemical Engineering, McGill University, Montréal, Québec, Canada.
Environ Int. 2012 Feb;39(1):66-72. doi: 10.1016/j.envint.2011.09.008. Epub 2011 Nov 4.
The presence of the synthetic estrogen 17α-ethinylestradiol (EE2) in waters at low levels is a concern due to its ability to act as an endocrine disruptor. Ozone (O(3)) is commonly used in water treatment and reacts with EE2 to form by-products having characteristics that are mostly unknown. The aim of this study was to identify the by-products of E2 and EE2 ozonation and determine their estrogenicity and toxicity relative to the parent compound. Ozonation by-products were identified via LC-MS analysis. The estrogenicity was measured using the YES assay, and toxicity was determined by monitoring effects on histology of fetal rat testes and testosterone secretion by these tissues. Two EE2 by-products were identified with open phenolic ring structures (masses 302 and 344 u). The Yeast Estrogen Screening (YES) assay showed a decreased but incomplete removal of estrogenicity after ozonation of EE2. Histological analysis of fetal testes revealed that neither E2 nor EE2, with or without ozonation, had any effect on seminiferous cord formation; however, a remarkable negative effect on testosterone secretion was observed, with EE2 by-products after ozonation showing the most rapid and extensive inhibition. These results show that the removal of EE2 via reaction with O(3) resulted in the formation of by-products that are less estrogenic (as demonstrated by the YES assay), but have a greater negative impact on testosterone secretion. Thus, the disappearance of the parent compound is not a sufficient endpoint, as the by-products created may be more toxic. Care should be taken when implementing oxidation applications such as ozone during waste water treatment.
水中低浓度合成雌激素 17α-乙炔基雌二醇（EE2）的存在令人担忧，因为它具有作为内分泌干扰物的能力。臭氧（O3）常用于水处理，与 EE2 反应形成具有大多数未知特征的副产物。本研究旨在鉴定 E2 和 EE2 臭氧化的副产物，并确定它们的雌激素活性和相对于母体化合物的毒性。通过 LC-MS 分析鉴定臭氧化副产物。使用 YES 测定法测量雌激素活性，通过监测对胎儿大鼠睾丸组织学的影响和这些组织的睾酮分泌来确定毒性。鉴定出两种具有开环酚结构的 EE2 副产物（质量分别为 302 和 344 u）。酵母雌激素筛选（YES）测定法表明，EE2 臭氧化后雌激素活性虽有所降低，但并未完全去除。胎儿睾丸的组织学分析表明，E2 和 EE2 无论是否臭氧化，都对精曲细管形成没有任何影响；然而，发现睾酮分泌受到显著抑制，臭氧化后的 EE2 副产物表现出最快和最广泛的抑制作用。这些结果表明，通过与 O3 反应去除 EE2 会形成雌激素活性降低（如 YES 测定法所示）但对睾酮分泌有更大负面影响的副产物。因此，母体化合物的消失并不是一个充分的终点，因为所产生的副产物可能毒性更大。在废水处理中实施氧化应用（如臭氧）时应谨慎。
