Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Primary producers (aquatic plants or algae):

72h-EC50 = 16.8 mg/L (green alga, grwoth reduction)

72h-EC10 = 2.84 mg/L (green alga, grwoth reduction)

Primary consumers (aquatic invertebrates):

24h-EC50 = 30 mg/L (daphnia, immobility)

Secondary consumers (fresh water fish):

96h-LC50 = 14.83 mg/L (Brachydanio rerio, mortality)

Toxicity to microorganisms:

3h-EC50 = 132 mg/L (activated sludge, respiration inhibition)

Additional information

Primary producers (aquatic plants or algae):

In a 72 h growth inhibition test on freshwater green alga Desmodesmus subspicatus according to relevant guideline and performed complient to GLP (key study, reliability category 1) 2 -chlorobenzaldehyd was found to inhibit the growth after 72 h with the following effect values (geometric mean measured exposure concentrations, growth reduction, mg/L): NOEC = 2.25; LOEC = 7.41; EC10 = 2.84; EC20 = 3.46; EC50 = 16.8.

Primary consumers (aquatic invertebrates):

The reliable (with restrictions, RL 2) experimental key study was performed close to guideline OECD 202. The test duration however is only 24h (according to OECD 202 part I (1984) instead of 48 h. The validity criteria are fulfilled and a reference substance (potassium dichromate) confirms the reliability of the study. The values for acute toxicity of 2 -chlorobenzaldehyde on Daphnia magna are

EC0 = 21 mg/L

EC10 = 24 mg/L

EC50 = 30 mg/L.

Secondary consumers (fresh water fish):

The key study from Hoechst on Brachydanio rerio was performed according to OECD guideline 203 with a static system. Determination of actual test concentrations had been precluded because of substance instability (reliability category 2). The 96h LC50 value for Brachydanio rerio determined in this study is 14.83 mg/L.

Toxicity to microorganisms:

In a respiration inhibition test with activated sludge from a municipal sewage treatment plant performed according to OECD 209 and GLP (reliability category 1) the test item had been found to inhibit microbial respration by half at a concentration of 132 mg/L (EC50, 95% CI 60.3 - 331 mg/L ).

Thus, for the freshwater compartment of the three trophic levels tested, testing for acute fish toxicity resulted in the lowest LC50 value of 14.83 mg/L.