Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Because the test substance was not stable in the test medium, the validation was related to double hydrolysed product (main hydrolytic product, which is more stable in the dilution water) according to Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures (OECD SERIES ON TESTING AND ASSESSMENT No. 23). The analytical determination of the test substance concentrations will also be based on this double hydrolysed product.

Because concentrations of the double hydrolysed product (in the two highest concentrations) have not been satisfactorily maintained within ± 20 percent of the nominal or measured initial concentration throughout the test, geometric means of measured concentrations were used for evaluations and results.

The evaluation using geometric means of measured concentrations:

72 hour - ErC50 = not evaluated (95% confidence limit: not evaluated)

72 hour - EyC50 = 2.81 mg· L-1 (95% confidence limit: 0.187 - 47.8 mg· L-1)

72 hour - ErC10 = 0.308 mg· L-1 (95% confidence limit: 0.078 - 1.22 mg· L-1)

72 hour - EyC10 = 0.007 mg· L-1 (95% confidence limit: 0.00 I -0.096 mg· L-1)

72 hour - NOECr < 3.26 mg· L-1

72 hour - NOECy < 3.26 mg· L-1

In addition, there was a deviation in the process of evaluating data in this test. At the calculation of the geometric mean of measured concentrations it is showed that the value of highest concentration (100 mg/L) is lower than the second highest concentration (56 mg/L) . For this reason, in the calculation of EC value the highest concentration was excluded, then the statistical software ToxRat Professional Version 3.2.1. was not able to calculate the value of 72 hour ErC50 (due to low inhibition). In this case, considering the inhibition, we temporarily consider the ErC50 is > 55.5 mg/L(geometric mean measured concentration of the second highest concenteation).

Key value for chemical safety assessment

EC50 for freshwater algae:
55.5 mg/L
EC10 or NOEC for freshwater algae:
0.308 mg/L

Additional information