3,5-diethyl-1,2-dihydro-1-phenyl-2-propylpyridine

Ecotoxicological Summary

Conclusion on classification

In the absence of adequate chronic aquatic toxicity information from all three trophic levels, the classification was based on the lowest of the short-term aquatic toxicity values from the three trophic levels (48-h EC₅₀ = 43% saturated solution in daphnids). Although analytical monitoring was conducted in the study, the substance was reported below the limit of quantitation (0.052 mg/L) in all test solutions for which chemical analysis was performed. The limit of quantitation was slightly below the water solubility of the substance of 0.05323 mg/L. Therefore, the toxicity of the substance was based upon the percent saturation of the predicted water solubility of the substance (i.e., 43% of 0.5323 mg/L), resulting in an estimated EC₅₀ of 0.023 mg/L. This estimated EC₅₀ value is uncertain (as it is based on neither directly measured or nominal concentrations nor an experimentally-determined water solubility); therefore, use of this value in environmental classification is highly precautionary. The substance was predicted to be not readily biodegradable through QSAR modeling. The octanol-water partition coefficient was experimentally determined to be log K_ow > 6.5 and predicted by QSAR modelling to be log K_ow= 6.53. Therefore, the substance was assigned a classification of Category Acute 1 and Category Chronic 1 for hazards to the aquatic environment, each with an M-factor of 10.