Sertraline is an antidepressant belonging to the class of selective serotonin reuptake inhibitors. It is frequently detected in aquatic environment because it cannot be completely degraded in the sewage plants. The effects and mechanisms of sertraline in mammals are well understood. However, its chronic effects in fish have been poorly evaluated. In this study, Japanese medaka (Oryzias latipes) was exposed to sertraline for 14 days, and the effects of sertraline on the fish brain were evaluated using a metabolomics approach. Exposure to 115 µg/L sertraline increased glutamate levels; however, this effect was suggested to be suppressed by several amino acids after 14 days of exposure. The effects in fish exposed to sertraline are unlikely to occur in actual aquatic environments.

We review the current challenges in the ecological risk assessment of ethylenediaminetetraacetic acid (EDTA) and cationic surfactants under Japan’s Chemical Substances Control Law. The complexity of EDTA toxicity assessment arises from its chelating properties, which influence metal bioavailability and ecological toxicity, making conventional assessment methods inadequate. Meanwhile, the toxicity of cationic surfactants is significantly affected by environmental factors, particularly organic matter content and water quality parameters. These variations pose substantial difficulties in achieving reliable toxicity assessments. While the Biotic Ligand Model (BLM) has been applied to address similar challenges in metal toxicity assessment, its effectiveness in evaluating EDTA and cationic surfactants has yet to be fully demonstrated. This paper examines existing evaluation methods, identifies their limitations, and proposes potential approaches for improving the reliability of risk assessments for these difficult-to-test substances.