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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Parent compound: no data available

Hydrolysis product mehanol: with high probability acutely not harmful to algae

Hydrolysis product HCl: Acutely very toxic for aquatic algae (pH dependent)

Key value for chemical safety assessment

Additional information

No data for the parent methyl chloroformate (CAS 79-22-1) are available. However, the parent compound rapidly hydrolyses in contact with water and forms methanol (CAS 67-56-1), HCl (CAS 7647-01-0) and CO2 (CAS 124 -38 -9). Therefore, the toxicity to aquatic green algae and cyanobacteria will be assessed based on the information available for the hydrolysis products methanol and HCl.

 

Parent compound methyl chloroformate:

No data available.

Hydrolysis product methanol:

In a key study conducted according to OECD 201 Guideline a concentration causing 50% inhibition in growth rate of 22000 mg/L for the green algae Selenastrum capricornutum was determined (Cho et al. 2008). The duration of the study was 96 hours. In a supporting study the toxicity threshold of methanol for the alga Scenedesmus quadricauda after an exposure of 8 days was reported to be at 8000 mg/L (Bringmann and Kuehn, 1978). Moreover, in another supporting study the 14-d EC50 value with different test species of blue-green algae was in the range between 20300 - 43290 mg/L (Stratton, 1987). The average concentration causing 50% inhibition in growth rate was found to be at 28400 mg/L during an exposure period of 10 – 14 days (Chlorella pyrenoidosa, Stratton and Smith, 1988).

Based on the available experimental data the hydrolysis product methanol is with high probability acutely not harmful to algae

Hydrolysis product HCl:

HCl was tested in a semi-static acute toxicity test according to OECD 203 with Cyprinus carpio. The 72-h ErC50 was 0.492 mg/L (acid equivalent to pH 5.3; MITI, 1999; peer reviewed data: OECD SIDS, 2002).

Based on the available experimental data the hydrolysis product HCl is considered to be acutely very toxic for aquatic algae (pH dependent). These data have not been taken into consideration to evaluate aquatic toxicity as observed effects are caused by a pH-shift in the test medium.