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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The inhibition of the degradation activity of activated sludge is not anticipated when the parent compound methyl formate or its hydrolysis products formic acid and methanol are introduced in appropriate low concentrations.

Key value for chemical safety assessment

Additional information

Parent compound methyl formate

The key study regarding toxicity to microorganisms is a growth inhibition test with Pseudomonas putida following theGerman Industrial Standard DIN 38412, part 8(1980). The EC50was determined to be > 10000 mg/L. The EC10is 8117 mg/L (BASF AG, 1988). However, according to the available hydrolysis study for the substance, Methyl formates' susceptibility to hydrolysis increases with pH as well as with temperature. The hydrolysis half-life ranges from 410 h at pH 4 and 20 °C to less than 1 hour at pH 9 and 25 °C (OECD 111, BASF SE, 2010). Therefore, it can be concluded, that under environmentally relevant conditions (pH 7-9) the rapid hydrolysis will be the major fate process of the methylformate due to the short half-life in aqueous solution. Therefore, this estimate may be of low relevance. Thus, the assessment of the aquatic toxicity of the substance is based on the available experimental data for the hydrolytic products: the inhibition of the degradation activity of activated sludge is not anticipated when the parent compound methyl formate or its hydrolysis products formic acid and methanol are introduced in appropriate low concentrations.formic acid and methanol.

Hydrolysis product formic acid/formate

In a key study conducted according to OECD TG 209 with domestic activated sludge the 3 -h IC50 for the hydrolysis product formic acid was determined to be higher than 10000 mg/L (BASF SE, rep. no.: 16EM1XA, 2016).

Hydrolysis product methanol

In an activated sludge respiration inhibition test according to OECD TG 209 an EC50 value of >1000 mg/L was reported by Klecka et al. (1985).

Overall, based on the available experimental data it can be concluded, that the inhibition of the degradation activity of activated sludge is not anticipated when the parent compound methyl formate or its hydrolysis products formic acid and methanol are introduced in appropriate low concentrations.