Triclosan, a widely used biocide broadly found in aquatic environments, is cause of concern due to its unknown effects on non-targets organisms. In this study, a multi biomarker approach was used in order to evaluate the 72 h-effect of triclosan on the freshwater alga Pseudokirchneriella subcapitata (Raphidocelis subcapitata). Triclosan, at environmental relevant concentrations (27 and 37 μg L⁻¹), caused a decrease of proliferative capacity, which was accompanied by an increase of cell size and a profound alteration of algae shape. It was found that triclosan promoted the intracellular accumulation of reactive oxygen species, the depletion of non-enzymatic antioxidant defenses (reduced glutathione and carotenoids) and a decrease of cell metabolic activity. A reduction of photosynthetic pigments (chlorophyll a and b) was also observed. For the highest concentration tested (37 μg L⁻¹), a decrease of photosynthetic efficiency was detected along with a diminution of the relative transport rate of electrons on the photosynthetic chain. In conclusion, triclosan presents a deep impact on the microalga P. subcapitata morphology and physiology translated by multiple target sites instead of a specific point (cellular membrane) observed in the target organism (bacteria). Additionally, this study contributes to clarify the toxicity mechanisms of triclosan, in green algae, showing the existence of distinct modes of action of the biocide depending on the microalga.

三氯生（Triclosan）是在水生环境中广泛发现的一种广泛使用的杀生物剂，由于其对非目标生物的未知作用而引起人们的关注。在这项研究中，为了评价三氯生对72的h-效果中使用的多生物标志物的方法的淡水藻类门Pseudokirchneriella subcapitata（Raphidocelis subcapitata）。三氯生，与环境有关的浓度（27和37μgL ^-1），导致增殖能力下降，并伴随着细胞大小的增加和藻类形状的深刻改变。发现三氯生可促进细胞内活性氧的积累，非酶抗氧化剂防御作用的减少（减少谷胱甘肽和类胡萝卜素）以及细胞代谢活性的降低。还观察到光合色素（叶绿素a和b）的减少。对于最高测试浓度（37μgL ^-1），检测到光合作用效率降低，同时电子在光合作用链上的相对迁移率降低。综上所述，三氯生对微藻假单胞菌具有深远的影响。形态和生理学由多个目标位点而不是在目标生物（细菌）中观察到的特定点（细胞膜）翻译而成。此外，这项研究有助于阐明三氯生在绿藻中的毒性机理，显示了取决于微藻的杀生物剂的不同作用方式的存在。