Methanol

Long-term toxicity to fish

Description of key information

NOEC: 450 mg/L

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

450 mg/L

Additional information

Guideline studies on chronic toxicity of methanol to fish are not available.

Kaviraj et al. investigated the toxicity of methanol towards fish (Oreochromic mossambicus) in a 90 day outdoor chronic toxicity test. The authors observed effects on the gonadosomatic index, the fecundity (not mentioned if and how this was observed) and maturity index (not mentioned if and how this was observed) and derived a NOEC of 23.75 mg/L

Due to several deficiencies in the test design this study has to be considered to be invalid. Furthermore, it can be concluded that the results observed are very much likely due to a statistically significant decrease in water quality at higher tests concentrations (probably due to the excess of bacterial growth) rather than direct methanol effects.

In an early-life-stage bioassay conducted with Oryzias latipes available by Gonzales-Doncel et al. (2008) NOECs range between 7900 - 15800 mg/L. Althoug this study cannot be used for the derivation of the PNEC aqua (in-vitro study with reduced duration of exposure) the result indicates that methanol has a very low long-term toxicity to fish.

Toxicity of methanol to early-life stages of fish (embryos, fish eggs, oocytes) has indeed been investigated according to several references in addition to Gonzales-Doncel et al., 2008, see for example Lammer et.al., Comparative Biochemistry and Physiology, Part C 149 (2009) 196–209; Chromcova et. al., Neuro Endocrinol Lett. 2012; 33 Suppl 3:60-5.; Zeljenkova et.al., Reprod Toxicol 2006 Aug; 22(2):285; Plachinta et.al., Cryo Letters. 2004 Nov-Dec; 25(6):415-24.

Methanol belongs to the category of organic chemicals exerting toxicity for aquatic organisms with a non-specific mode of action. The acute and chronic toxicity may be estimated for such kind of chemicals using QSAR methods. The ECOSAR model (version 1.11, US EPA, July 2012) predicts for methanol a chronic toxicity value of about 450 mg/L (equivalent to a NOEC).

The prediction fulfils the OECD criteria on evaluation on QSARs and grouping of chemicals:

Algorithm used for the prediction:

log 30-d chronic Value (mmol/L): -0.8508 logKow + 0.6063 (r² = 0.7393, n = 46)

Applicability domain

Application: Solvents, non-reactive, non-ionizable neutral organic compounds 1. Alcohols 2. Acetals 3. Ketones 4. Ethers 5. Alkyl halides 6. Aryl halides 7. Aromatic hydrocarbons 8. Halogenated aromatic hydrocarbons 9. Halogenated aliphatic hydrocarbons 10. Sulfides and di-sulfides

Maximum LogKow: 8.0 Maximum MW: 1000

Goodnes-of fit and robustness

Training set is provided in the document "Neutral Organics - QSAR Equation Document" availabble in the software documentation of ECOSAR

Predictivity

The QSAR has appropriate measures of predictivity as determinrd by external validation. For details see De Haas et al., Internal and external validation of the long-term QSARs for neutral organics to fish from ECOSAR (SAR and QSAR in Environmental Research, Vol. 22, No. 5-6, p. 545-559, 2011)

Mechanistic interpretation

Mechanistic basis of the model is the reversible, drug-induced loss of consciousness (general anaesthesia), better known as baseline toxicity

The predicted value is therefore used as NOEC as key value for chemical safety assessment