Z-85

Short-term toxicity to aquatic invertebrates

Description of key information

The acute toxicity of the test material to the freshwater invertebrate Daphnia magna has been investigated and gave a 48 hour EL50 value of 82 mg/L loading rate WAF with 95% confidence limits of 68 – 110 mg/L loading rate WAF.  The No Observed Effect Loading rate at 48 hours was 32 mg/L loading rate WAF.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

82 mg/L

Additional information

A key study study to OECD Guideline 202 and EC Method C.2 was performed to assess the acute toxicity of the test material to Daphnia magna. Following a preliminary range-finding test, twenty daphnids (2 replicates of 10 animals) were exposed to Water Accommodated Fractions (WAFs) of the test material over a range of nominal loading rates of 10, 18, 32, 56, and 100 mg/L for 48 hours at a temperature of 21 to 22 degrees C under static test conditions. The number of immobilised Daphnia were recorded after 24 and 48 hours.

The 48 hour EL50 for the test material to Daphnia magna based on nominal loading rates was 82 mg/L loading rate WAF with 95% confidence limits of 68 to 110 mg/L loading rate WAF. The No Observed Effect Loading rate was 32 mg/L loading rate WAF. 

Analysis of samples taken at 0 hours showed results of less than the limit of quantitation (LOQ) of the analytical method which was assessed to be 0.0047 mg/L. Given that the 0-hour samples were less than the LOQ, analysis of samples at 48 hours was not conducted as it would provide no additional information on exposure concentrations. Therefore, given that toxicity cannot be attributed to a single component or a mixture of components but to the test material as a whole, and the dissolved test material was below the quantifiable limit of the analytical method, the results were based on nominal loading rates only.