National Research Council, Institute of Biology and Agricultural Biotechnology (IBBA), Pisa Unit, Research Area of Pisa, Via Moruzzi 1, 56124, Pisa, Italy.
Ecotoxicol Environ Saf. 2011 Mar;74(3):253-8. doi: 10.1016/j.ecoenv.2010.10.039. Epub 2010 Nov 18.
Nonylphenol ethoxylates (NPnEOs, where n is the number of ethoxylic units in the molecule) are non-ionic surfactants widely used for domestic and industrial purposes. 4-Nonylphenol (4-NP), the main product of NPnEO biodegradation, is a toxic xenobiotic compound classified as endocrine disrupter. While numerous studies reported the toxicity and oestrogenic activity of nonylphenols, little is known about the mutagenicity of these compounds. In this paper, the genotoxicity of 4-NP and NPnEO mixtures was evaluated by using the D7 strain of Saccharomyces cerevisiae as experimental model. The same genotoxicity tests were applied to effluents deriving from experimental packed-bed bioreactors, developed for the treatment of NPnEO contaminated wastewater, in order to evaluate the residual genotoxic potential with respect to the influent waste. The target compounds fed to the bioreactors were 4-NP and NPnEO mixtures possessing an average of 5 or 1.5 ethoxylic units (Igepal CO-520 and Igepal CO-210, respectively). The results showed that 4-NP induced significant cytotoxic effect on S. cerevisiae cells at 50 mg/L, as well as mutagenic effects at the lowest tested concentrations (12 and 25 mg/L). 4-NP was the most genotoxic compound among those assayed, followed by Igepal CO-210, whereas Igepal CO-520 did not induce genotoxicity at any of the assayed concentrations. The genotoxic effects of 4-NP on yeast cells disappeared after the treatment of 4-NP artificially contaminated water in the bioreactor. This indicates that the biological treatment is capable of removing not only the pollutant, but also the toxicity associated to the compound and its degradation metabolites. This study represents, to the best of our knowledge, the first report that evaluates the genotoxicity of both 4-NP, NPnEOs and their potential aerobic degradation products on an eukaryotic organism. The obtained results suggest that the S. cerevisiae D7 strain is a very effective model microorganism to study the induction of genotoxic damage by the compounds under study. Moreover, this yeast assay has been proved effective to evaluate the detoxification effect deriving from biotreatment processes.
壬基酚乙氧基化物（NPnEOs，其中 n 是分子中乙氧基单元的数量）是广泛用于家庭和工业用途的非离子表面活性剂。4-壬基酚（4-NP）是 NPnEO 生物降解的主要产物，是一种有毒的异生物质化合物，被归类为内分泌干扰物。虽然许多研究报告了壬基酚的毒性和雌激素活性，但对这些化合物的致突变性知之甚少。在本文中，使用酿酒酵母 D7 菌株作为实验模型，评估了 4-NP 和 NPnEO 混合物的遗传毒性。同样的遗传毒性测试也应用于实验填充床生物反应器的流出物中，该生物反应器是为处理 NPnEO 污染废水而开发的，以评估相对于进水废物的残留遗传毒性潜力。进料到生物反应器的目标化合物是 4-NP 和具有 5 或 1.5 个乙氧基单元的 NPnEO 混合物（分别为 Igepal CO-520 和 Igepal CO-210）。结果表明，4-NP 在 50mg/L 时对酿酒酵母细胞产生了显著的细胞毒性作用，并且在最低测试浓度（12 和 25mg/L）下也产生了致突变作用。在测试的化合物中，4-NP 是最具遗传毒性的化合物，其次是 Igepal CO-210，而 Igepal CO-520 在测试的任何浓度下均未产生遗传毒性。在生物反应器中对人工污染水进行 4-NP 处理后，4-NP 对酵母细胞的遗传毒性作用消失了。这表明生物处理不仅能够去除污染物，还能够去除与化合物及其降解代谢物相关的毒性。就我们所知，这项研究代表了首次评估 4-NP、NPnEOs 及其潜在好氧降解产物对真核生物遗传毒性的研究。所得结果表明，酿酒酵母 D7 菌株是研究研究化合物诱导遗传毒性损伤的非常有效的模式微生物。此外，该酵母测定法已被证明可有效评估生物处理过程产生的解毒效果。
