Hexachlorocyclopentadiene

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

other: Assessment based on available data on the toxicity of the substance to aquatic plants identified in the literature.

Adequacy of study:

weight of evidence

Study period:

2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Assessment based on available data on the toxicity of the substance to aquatic plants identified in the literature.

Principles of method if other than guideline:

Assessment based on available data on the toxicity of the substance to aquatic plants identified in the literature.

GLP compliance:

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.24

Nominal / measured:

not specified

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: Assessment based on available data on the toxicity of the substance to aquatic plants identified in the literature.

Validity criteria fulfilled:

yes

Conclusions:

An assessment was performed based on available data on the toxicity of the substance to aquatic plants identified in the literature. An EC50 of 0.24 mg/l (growth rate; 48 hour) has been identified as the key value for calculation of the Predicted No Effect Concentration (PNEC) in water and subsequent determination of the Risk Characterisation Ration (RCR).

Executive summary:

The results of a limited number of studies on the toxicity of hexachlorocyclopentadiene were obtained from the EU RAR (European Commission, 2007) on the substance and evaluated for relevance, reliability and adequacy for use in this Registration Assessment Report for REACH registration purposes.

The studies on freshwater algae were of mixed relevance. All reported results on marine species of algae were found to be of limited relevance, due to lack of access to original sources of data which prevents confirmation of the test species remaining in the exponential growth stage for the duration of the study.

Based on this assessment of the relevance, reliability and adequacy of the available data an EC50 of 0.24 mg/l (growth rate; 48 hour) has been identified as the key value for calculation of the Predicted No Effect Concentration (PNEC) in water and subsequent determination of the Risk Characterisation Ration (RCR).

The data used to form this Registration Assessment Report supports the harmonised classification of the substance as Aquatic Acute 1 and Aquatic Chronic 1, with the respective Hazard Statements H-400 (Very toxic to aquatic life) and H-410 (Very toxic to aquatic life with long lasting effects). Based on the availability of reliable data for evaluation purposes, and the presence of this harmonised classification, it can be concluded that further testing for this endpoint would not be necessary and would be unlikely to provide further information on toxicity to aquatic plants for use in the REACH registration of hexachlorocyclopentadiene.

Description of key information

An assessment was conducted based on available data on the toxicity of the substance to aquatic plants identified in the literature. A 48-hour EC50 of 0.24 mg/l has been determined based on the inhibition of the growth rate of Scenedesmus subspicatus.

Key value for chemical safety assessment

EC50 for freshwater algae:

0.24 mg/L