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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

Data were taken from phenol dossier - read across appreach was chosen because the content of phenol in the registered substance could be up to 50% (w/w).
Reliable 96 h LC50 values results are available from 18 short-term tests with several fish species. The LC50 values are in the range 8.9 to 67.5 mg/L. The tests were conducted under flow-through conditions or semi-static conditions and the exposure concentrations were analytically verified in most of the studies. Colgan et al. (1982) demonstrated the stability of phenol under semi-static conditions (48 h interval).
The most sensitive endpoint was the LC50 of 8.9 mg/L, based on measured concentrations, obtained in a 96-h acute toxicity study under flow-through conditions (DeGraeve et al 1980) with the cold water fish rainbow trout O. mykiss.

Key value for chemical safety assessment

LC50 for freshwater fish:
8.9 mg/L

Additional information

The data on short term toxicity of phenol on fish is presented in EU RAR (2006) in Section 3.2.1 (Aquatic compartment (incl. Sediment), page 36ff). It is stated that 96-hour LC50-values are in the range of 5.02 mg/L to 47.5 mg/L.Oncorhynchus mykiss seems to be the most sensitive fish species. The lowest effect LC50 value of 5.02 mg/L was obtained with this species in a semi-static system. The experimental values are in reasonable agreement with QSAR estimation according to the TGD (1996) which results in a fish (96-hour) LC50 of 55 mg/L for polar narcotic acting substances.

For the current assessment the study of McLeay (1976, LC50 5.02 mg/L) was regarded not valid due to the deviations from the standard conditions of OECD/ISO /EEC guidelines and should not be used as relevant endpoint for risk assessment (Fish loading (1.5 g/L) higher, temperature (20.5°C) higher than requested in OECD 203). The high fish loading and the high temperature will induce stress symptoms in the cold water fish O. mykiss and may result in higher sensitivity to phenol.

Reliable 96 h LC50 values results are available from 18 short-term tests with several fish species and a 14 days GLP study whose LC50 fits within the range of the other studies. The LC50 values are in the range 8.9 to 67.5 mg/L. The tests were conducted under flow-through conditions or semi-static conditions and the exposure concentrations were analytically verified in most of the studies. Colgan et al. (1982) demonstrated the stability of phenol under semi-static conditions (48 h interval). The most sensitive endpoint was the LC50 of 8.9 mg/L, based on measured concentrations, obtained in a 96-h acute toxicity study under flow-through conditions (DeGraeve et al., 1980) with the cold water fish rainbow trout O. mykiss. The study was conducted according to the US EPA Guideline (Methods for acute toxicity tests with fish, macroinvertebrates, and amphibians, 1974). The effect concentration is confirmed by the result of the 96-h acute toxicity study with Pimephales promelas exposed under flow through conditions at 25 °C, conducted according to US EPA Guideline (DeGraeve et al., 1980). The LC50 was found to be 24.9 mg/L, based on measured concentrations.

Moreover, the prolonged toxicity of phenol to Poecilia reticulata was investigated in a study conducted according to OECD Guideline 204 (Fish, Prolonged Toxicity Test: 14-day Study) under semi-static conditions. The stability of the test solution was investigated over a period of 5 days via TOC analysis. After 5 d 92.1% of the initial test substance concentration was found. The 14 d NOEC, LC50, and LC100 were determined to be 4, 21.93, and >16 mg/L nominal, respectively.