Vinyl chloroacetate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

other: An assessment was performed based on literature data on the degradation products of VCA

Adequacy of study:

weight of evidence

Study period:

09 May 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: An assessment was performed based on literature data on the degradation products of the substance

Justification for type of information:

An experimental study to determine the toxicity of VCA to aquatic algae and cyanobacteria was not considered necessary, nor scientifically justified, since the registered substance is expected to undergo rapid abiotic transformation upon contact with water. Therefore the degradation products of VCA were assessed instead in order to calculate an EC50 value for VCA.

Qualifier:

no guideline required

Principles of method if other than guideline:

An assessment was performed based on literature data on the degradation products of VCA

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.036 mg/L

Remarks on result:

other: Expert assessment based on literature data on degradation products

Validity criteria fulfilled:

not applicable

Conclusions:

It is not scientifically necessary to perform a study on the toxicity of VCA to aquatic algae and cyanobacteria, since it hydrolyses rapidly in water to form Chloroacetic acid and Acetaldehyde. The aquatic toxicity of VCA is expected to be driven by the toxicity of these degradation products. The EC50 of VCA was calculated to be 0.03584 mg/L based on the lowest calculated EC50 values across both degradation products. This is the most sensitive trophic level with regards to the aquatic toxicity of VCA.

Executive summary:

VCA has been found to hydrolyse rapidly (t1/2 12 hrs) upon contact with water to give two main degradation products: Chloroacetic acid (CAS 79-11-8 / EC 201-178-4) and Acetaldehyde (CAS 75-07- 0 / EC 200-836-8). Subsequently, the toxicity of VCA to aquatic algae and cyanobacteria was determined by means of expert assessment, based on the ecotoxicity of its degradation products, for which substantial literature data is already available. A literature search was conducted to obtain a value for the toxicity of Chloroacetic acid and Acetaldehyde to aquatic algae and cyanobacteria.

Considering the uses of VCA, it is the toxicity to freshwater species that was considered.

The lowest calculated EC50 value was taken from across both degradation products, in order to take the most conservative approach. Chloroacetic acid was found to be the degradation product with the lowest EC50. For the purpose of the assessment it was assumed that VCA hydrolyses entirely into the two degradation products. The 48 hour EC50 value for chloroacetic acid is 0.028 mg/L. To produce this amount of chloroacetic acid, 0.03584 mg/L VCA must be hydrolysed. Therefore, it can be concluded that the 48 hour EC50 for the toxicity of VCA to aquatic algae and cyanobacteria is 0.03584 mg/L.

Description of key information

It is not scientifically necessary to perform a study on the toxicity of VCA to aquatic algae and cyanobacteria, since it hydrolyses rapidly in water to form Chloroacetic acid and Acetaldehyde. The 48 hour EC50 for the toxicity of VCA to aquatic algae and cyanobacteria was calculated to be 0.03584 mg/L based on the amount of VCA required to produce 0.028 mg/L of chloroacetic acid. This value is the lowest calculated EC50 value across the degrdation products. This is the most sensitive trophic level with regards to the aquatic toxicity of VCA, and therefore the PNEC calculation and classification are based upon this value.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.036 mg/L