Si Haoyu, Zhou Guoquan, Luo Yu, Wang Zhuoxuan, Pan Xuejun, Dao Guohua
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
Yunnan Academy of Ecological and Environmental Science, Yunnan Key Laboratory of Pollution Process and Control of Plateau Lake-Watersheds, Kunming 650034, China.
Toxics. 2024 Aug 17;12(8):596. doi: 10.3390/toxics12080596.
The threat posed by water pollutants to aquatic ecosystems and human health cannot be overlooked, and the assessment of the toxicity of these contaminants is paramount to understanding their risks and formulating effective control measures. Luminescent bacteria-based assays, as a vital tool in evaluating contaminant toxicity, encounter a challenge in ensuring accuracy due to the phenomenon of "Hormesis" exhibited by pollutants towards biological entities, which may skew toxicity assessments. This study elucidated the specific effects of pollutants on luminescent bacteria at different concentrations, used modeling to characterize the effects and predict their toxicity trends, and explored the applicable concentration ranges for different pollutants. Research revealed that six typical pollutants, namely PAHs, endocrine disruptors, antibiotics, pesticides, heavy metals, and phytosensory substances, could promote the luminescence intensity of luminescent bacteria at low concentrations, and the promotional effect increased and then decreased. However, when the concentration of the substances reached a certain threshold, the effect changed from promotional to inhibitory, and the rate of inhibition was directly proportional to the concentration. The EC50 values of six types of substances to luminescent bacteria is as follows: endocrine disruptors > pesticides > antibiotics > heavy metals > polycyclic aromatic hydrocarbons > chemosensory agents. The effect curves were further fitted using the model to analyze the maximum point of the promotion of luminescence intensity by different substances, the threshold concentration, and the tolerance of luminescent bacteria to different substances. The maximum promotion of bacterial luminescence intensity was 29% for Bisphenol A at 0.005 mg/L and the minimum threshold concentration of chromium was 0.004 mg/L, and the maximum bacterial tolerance to erythromycin is 6.74. In addition, most of the current environmental concentrations had a positive effect on luminescent bacteria and may still be in the range of concentrations that promote luminescence as the substances continue to accumulate. These findings will enhance the accuracy and comprehensiveness of toxicity assessments, thereby facilitating more informed and effective decision-making in the realms of environmental protection and pollution management.
水污染物对水生生态系统和人类健康构成的威胁不容忽视，评估这些污染物的毒性对于了解其风险并制定有效的控制措施至关重要。基于发光细菌的检测方法作为评估污染物毒性的重要工具，由于污染物对生物实体表现出“兴奋效应”现象，在确保准确性方面面临挑战，这可能会使毒性评估产生偏差。本研究阐明了不同浓度污染物对发光细菌的具体影响，利用建模来表征这些影响并预测其毒性趋势，同时探索了不同污染物的适用浓度范围。研究发现，六种典型污染物，即多环芳烃、内分泌干扰物、抗生素、农药、重金属和植物感知物质，在低浓度时可促进发光细菌的发光强度，且促进作用先增大后减小。然而，当这些物质的浓度达到一定阈值时，作用从促进变为抑制，抑制率与浓度成正比。六种物质对发光细菌的半数效应浓度（EC50）值如下：内分泌干扰物＞农药＞抗生素＞重金属＞多环芳烃＞化学感知剂。利用该模型进一步拟合效应曲线，分析不同物质促进发光强度的最大值点、阈值浓度以及发光细菌对不同物质的耐受性。双酚A在0.005mg/L时对细菌发光强度的最大促进率为29%，铬的最低阈值浓度为0.004mg/L，发光细菌对红霉素的最大耐受性为6.74。此外，当前大多数环境浓度对发光细菌有积极影响，随着物质不断积累，可能仍处于促进发光的浓度范围内。这些研究结果将提高毒性评估的准确性和全面性，从而有助于在环境保护和污染管理领域做出更明智、有效的决策。
