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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

ErL50 = 20 mg/L loading rate WAF

NOELR = 10 mg/l

LOELR = 32 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:
20 mg/L

Additional information

The key study was conducted in line with GLP and the standardised guidelines OECD 201and EU Method C.3 and assessed the effect of the test material on the growth of the green alga Pseudokirchneriella subcapitata.

Due to the low aqueous solubility and complex nature of the test material, it was prepared as a Water Accommodated Fraction (WAF).

Following preliminary range-finding tests, the algal cells were exposed to WAFs of the test material over a range of nominal loading rates of 1.0, 3.2, 10, 32 and 100 mg/L (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1 °C.

Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group.

Under the conditions of this study, the EL50 for growth was determined to be 20 mg/L loading rate WAF (95 % confidence limits 10 - 32 mg/L loading rate WAF), with the NOELR and LOELR being 10 and 32 mg/L, respectively.

Analysis of the test preparations at 0 hours showed measured test concentrations to range from 0.91 mg/L at 1.0 mg/L loading rate WAF through to 98 mg/L at 100 mg/L loading rate WAF whilst concentrations in the range of 0.92 mg/L at 1.0 mg/L loading rate WAF through to 72 mg/L at 100 mg/L loading rate WAF were obtained at 72 hours.

Given that the toxicity cannot be attributed to a single component or a mixture of components but to the test item as a whole the results were based on nominal loading rates only.