Ethanol

Long-term toxicity to fish

Description of key information

OECD212: NOEC=250mg/l.

Chronic 2 generation limit dose study (104days): NOEC>79mg/L

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

250 mg/L

Additional information

In a study which approximated to an OECD212 Embryo and Sac-fry stage test, ethanol was found to exhibit a no effect level of 1000mg/l or more for most end points. However, for the end point of shortening of motoneuron axons (the study was specifically interested in neurotoxicity end points) a lower NOEC of 250mg/l was observed. Long term tests are expected to cover all stages of the life cycle to give an accurate estimate of chronic toxicity. It is therefore expected that the embryo and sac fry test would be less sensitive than a full early life stage test. However, for substances with a log Kow <4 that have a non specific narcotic mode of action (such as ethanol) the difference in sensitivity between the two tests would be expected to be small. An OECD 212 study can therefore be considered as an appropriate protocol to assess the long term toxicity of ethanol to fish (Zhang, 2013).

In two similar studies that examined the effect of short term acute exposure to ethanol at critical stages of zebrafish embryo development during the first 27 hours post fertilisation, and during the 6 -48 period post fertilisation, ethanol was found to exhibit a no effect level of 1000mg/l for all developmental end points examined (Zhang 2013, 2014).

In a study to assess the chronic effects of a known environmental toxicant on reproductive status of medaka (Oryzias latipes) over two generations of continuous exposure, ethanol was used as a solvent. The study therefore provided information on the chronic toxicity to fish of ethanol at a limit dose of 79mg/L, the concentration of vehicle used in the study. The exposure study of the parental (F0) medaka was begun on embryos within 24 h postfertilization and continued with monitoring through embryological development, hatching, posthatch survival, growth, sexual differentiation, and reproduction using flow-through exposures for up to 104 d. Eggs spawned from the F0 fish at 102 and 103 d posthatch were also examined for hatchability, survival after hatching, growth, and sexual differentiation until 60 d posthatch. There were no adverse effects seen in this study and therefore the NOEC can be considered to be in excess of 79mg/L from this study.