Methyl formate

Short-term toxicity to aquatic invertebrates

Description of key information

The parent compound methyl formate along with its hydrolysis products formic acid and methanol are with high probability acutely not harmful to aquatic invertebrates.

 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Remarks:

Parent compound (CAS 107-31-3)

Effect concentration:

> 500 mg/L

Fresh water invertebrates

Dose descriptor:

EC50

Remarks:

Hydrolysis product formic acid

Effect concentration:

365 mg/L

Fresh water invertebrates

Dose descriptor:

EC50

Remarks:

Hydrolysis product methanol

Effect concentration:

> 10 000 mg/L

Marine water invertebrates

Marine water invertebrates

Dose descriptor:

LC50

Remarks:

Parent compound (CAS 107-31-3)

Effect concentration:

>= 320 - <= 560 mg/L

Marine water invertebrates

Dose descriptor:

LC50

Remarks:

Hydrolysis product formic acid

Effect concentration:

1 308 mg/L

Additional information

Parent compound (CAS 107-31-3)

Data on acute toxicity to aquatic invertebrates are available for Daphnia magna and a marine species. The Daphnia magna study was performed according to EU Method C.2 in a static test system. The 48 -h EC50 is > 500 mg/L, related to the nominal concentration (BASF AG, 1988). With the marine Crustacea Chaetogammarus marinus a 96 -LC50 of 320 -560 mg/L was determined (Adema & Bakker, 1984).

Moreover, 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 methyl formate due to the short half-life in aqueous solution. Therefore, this estimate may be of low relevance. Thus, the assessment of the short-term toxicity of the substance is also based on the available experimental data for the hydrolytic products: formic acid and methanol.

 

Hydrolysis product formic acid (CAS 64-18-6):

After 48 hours of exposure of Daphnia magna to ammonium formate in a GLP study following OECD TG 202, an EC50 of 365 mg/L (nominal, verified analytically) was determined (Fraunhofer, 2005).

In a static saltwater study according to a national British guideline using brown shrimp (Crangon crangon) a 96-LC50 of 1308 mg/L was determined (Huntington, 1992). A potassium formate was used as a test substance in this study.

The ammonium formate as well as the potassium formate are salts of the hydrolysis product formic acid. Formic acid changes the pH of the test solutions towards acidic conditions. When using ammonium and potassium salts as test substances, the pH is not affected. Therefore, both substances are suitable to investigate the sensitivity of fish towards formic acid under pH-neutralised conditions.

Hydrolysis product methanol (CAS 67-56-1):

In the key study conducted according to the DIN 38412 P. 11 with Daphnia magna as a test specie. No adverse effects were reported up to the highest test concentration of 10000 mg/L (nominal, Kuehn et al., 1989)

This result was supported by a study conducted according to the OECD 202 with Daphnia magna as a test specie. No adverse effects were were reported up to 18260 mg/L after 96-h exposure (Dom et al., 2012).

 

Overall, based on the available experimental data it can be concluded, that the parent compound methyl formate along with its hydrolysis products formic acid and methanol are with high probability acutely not harmful to aquatic invertebrates.