Ecotoxicology of Aquatic Microorganisms Laboratory, EcotoQ, GRIL, TOXEN, Department of Biological Sciences, Université du Québec À Montréal, Montréal Succ. Centre-Ville, Montréal, QC, H3C 3P8, Canada.
Chemistry Department, Université du Québec À Montréal, EcotoQ-TOXEN, Succ Centre-Ville, Montreal, QC, H3C 3P8, Canada.
Environ Sci Pollut Res Int. 2024 Oct;31(49):59382-59397. doi: 10.1007/s11356-024-35122-8. Epub 2024 Oct 1.
The phytotoxicity and removal of atrazine and S-metolachlor in sterile duckweed systems were estimated in this study. Herbicides were added at environmentally relevant ranges: 0-400 µg/L for atrazine or 0-200 µg/L for S-metolachlor in systems with Spirodela polyrhiza or Lemna minor. Toxicity biomarkers, i.e., changes in plant biomass, surface area, chlorophyll fluorescence parameters, pigments, lipid peroxidation, protein concentration, and antioxidative enzyme activities in plants were estimated after 7 days. S. polyrhiza (RGR-EC = 164.8 µg/L) was more tolerant to atrazine than L. minor (RGR-EC = 101.0 µg/L). Atrazine caused damage to photosystem II (Φ), a reduction in electron transport between PSII and PSI (Φ'), as well as disruption in energy distribution pathways (decrease in qPrel and increase in UQFrel), most prominently in L. minor. However, L. minor (RGR-EC = 128.9 µg/L) was more tolerant to S-metolachlor than S. polyrhiza (RGR-EC = 15.5 μg/L). The highest sensitivity of S. polyrhiza to S-metolachlor was attributed to a decrease in absorbed energy used in photochemistry (qPrel) and an increase in lipid peroxidation, indicating that S. polyrhiza plants were experiencing oxidative stress. Residual pesticide analysis in the water after seven days allowed us to conclude that plants were responsible for reducing up to 16.5% of atrazine and 28.7% of S-metolachlor in the duckweed system. S. polyrhiza showed higher atrazine phytoremediation capacity than L. minor. S. polyrhiza was more efficient at an environmentally relevant concentration of S-metolachlor (25 μg/L) and L. minor at higher concentrations (200 μg/L).
本研究估计了无菌浮萍系统中莠去津和 S-甲草氯的植物毒性和去除率。在含有紫萍或浮萍的系统中，莠去津的添加浓度为 0-400μg/L，S-甲草氯的添加浓度为 0-200μg/L，这两个浓度范围均与环境相关。7 天后，测定了植物生物量、表面积、叶绿素荧光参数、色素、脂质过氧化、蛋白质浓度和抗氧化酶活性等毒性生物标志物的变化。与浮萍相比，紫萍对莠去津的耐受性更强（RGR-EC=164.8μg/L）。莠去津对 PSII（Φ）造成损伤，降低 PSII 和 PSI 之间的电子传递（Φ'），并破坏能量分配途径（qPrel 降低和 UQFrel 升高），对浮萍的影响最为显著。然而，浮萍对 S-甲草氯的耐受性（RGR-EC=128.9μg/L）比紫萍更强（RGR-EC=15.5μg/L）。紫萍对 S-甲草氯的高敏感性归因于用于光化学的吸收能量减少（qPrel）和脂质过氧化增加，这表明紫萍植物正在经历氧化应激。七天后对水中残留农药的分析使我们能够得出结论，植物负责减少浮萍系统中高达 16.5%的莠去津和 28.7%的 S-甲草氯。与浮萍相比，紫萍具有更高的莠去津植物修复能力。在环境相关浓度的 S-甲草氯（25μg/L）下，紫萍的效率更高，而在较高浓度（200μg/L）下，浮萍的效率更高。
