由于持久性有机污染物的显著特征,二恶英在公共卫生和环境保护方面引起关注。评估二恶英降解途径的毒性风险至关重要。OCDD,1,2,3,4,6,7,8-HpCDD,和1,2,3,4,6,7,8-HpCDF,它们在环境中非常丰富,具有很强的生物降解能力,在这项研究中被选为前体分子。首先,它们的转化途径是在生物代谢代谢过程中推导出来的,微生物好氧,微生物厌氧,和光降解途径,利用密度泛函理论(DFT)计算吉布斯自由能,推断转化途径发生的可能性。其次,使用TOPKAT建模方法评估了前体及其降解产物的致癌潜力。借助正指标(0-1)归一化方法和热图分析,发现某些转化产物的毒性作用显着增加,推断与转化产品的结构有关。同时,使用分子对接和主观分配方法定量评估二恶英转化产物的内分泌干扰作用强度,研究发现,具有较高含量的氯原子和类似于甲状腺激素的分子的二恶英转化产物表现出更高的内分泌干扰风险。最后,借助负指标(1-2)标准化方法对各降解途径引起的环境健康风险进行综合评估,为避免二恶英降解转化带来的毒性风险提供了理论依据。此外,利用3D-QSAR模型验证了本研究的必要性和合理性。本文为从降解途径推断二恶英降解副产物的毒性评价提供了理论支持和参考意义。
Due to the significant POPs characteristics, dioxins caused concern in public health and environmental protection. Evaluating the toxicity risk of dioxin degradation pathways is critical. OCDD, 1,2,3,4,6,7,8-HpCDD, and 1,2,3,4,6,7,8-HpCDF, which are highly abundant in the environment and have strong biodegradation capabilities, were selected as precursor molecules in this study. Firstly, their transformation pathways were deduced during the metabolism of biometabolism, microbial aerobic, microbial anaerobic, and photodegradation pathways, and density function theory (DFT) was used to calculate the Gibbs free energy to infer the possibility of the occurrence of the transformation pathway. Secondly, the carcinogenic potential of the precursors and their degradation products was evaluated using the TOPKAT modeling method. With the help of the positive indicator (0-1) normalization method and heat map analysis, a significant increase in the toxic effect of some of the transformation products was found, and it was inferred that it was related to the structure of the transformation products. Meanwhile, the strength of the endocrine disrupting effect of dioxin transformation products was quantitatively assessed using molecular docking and subjective assignment methods, and it was found that dioxin transformation products with a higher content of chlorine atoms and molecules similar to those of thyroid hormones exhibited a higher risk of endocrine disruption. Finally, the environmental health risks caused by each degradation pathway were comprehensively assessed with the help of the negative indicator (1-2) standardization method, which provides a theoretical basis for avoiding the toxicity risks caused by dioxin degradation transformation. In addition, the 3D-QSAR model was used to verify the necessity and rationality of this study. This paper provides theoretical support and reference significance for the toxicity assessment of dioxin degradation by-products from inferred degradation pathways.