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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

The lowest 96-h LC50 is 193 mg/Lfor the freshwater Pimephales promelas. For marine water fish the lowest toxicity value was the 96-h LC50 97 mg/l found in Fundulus heteroclitus.

Key value for chemical safety assessment

LC50 for freshwater fish:
193 mg/L
LC50 for marine water fish:
97 mg/L

Additional information

Freshwater

Eleven acute toxicity studies are reported for 5 freshwater fish species. Three studies were conducted using a flow-through system with analysis of the test solutions, on Pimephales promelas. The results were based on measured concentrations and are considered valid, with 96h LC50s of 193 mg/L (Alexander et al., 1978) 330 mg/L (Geiger et al., 1986) and 502 mg/L (Dill et al, 1987); a 192 -h LC50 of 471 mg/L was also reported (Dill et al, 1987). Although there is some difference between the different 96-h LC50 values, they appear equally reliable. An EC50 based on loss of equilibrium was also reported (Geiger et al., 1986) but was identical to the LC50, which suggests there were no such effects at concentrations below those that caused mortality. A study with Lepomis macrochirus (Buccafusco et al., 1981) was carried out as a static test in a closed system but without analysis. The result could be used with restrictions, but was not lower than the lowest valid LC50.

Other studies were static tests and all of them were conducted without analysis of the test concentrations, and were considered not valid.

 

Marine water

Two acute toxicity studies are reported for 2 marine fish species. The study with Fundulus heteroclituswas expressed as measured concentrations and provided some information on the decline in concentration with time. The salinity for the study was 10‰, approximately 30% full seawater. The study is valid and gave a 96h LC50 of 97 mg/L which is the lowest toxicity value for marine fish (Burton and Fisher, 1990).

The study with Cyprinodon variegatus(Heitmüller et al, 1981) is not considered valid because it was a static test without analysis and with no apparent measures to prevent volatile loss of the substance. LeBlanc (1980) and US Department of Commerce (1978) appear to be secondary sources for the same study, although the LC50 quoted is slightly different (331 mg/L rather than 330 mg/L).