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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Under the conditions of this study, the EL50 for growth was determined to be 38 mg/L loading rate WAF, with the NOELR and LOELR 6.25 and 12.5 mg/L, respectively.
As a result of the EL50 value, in conjunction with the substance's physico-chemical properties, the test material requires classification for being hazardous to the aqueous environment and as such is categorised as Chronic Category 3 in accordance with EU criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:
38 mg/L
EC10 or NOEC for freshwater algae:
6.25 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. It was assigned a reliability score of 1 in accordance with the criteria detailed by Klimisch (1997).

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 6.25, 12.5, 25, 50 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 38 mg/L loading rate WAF, with the NOELR and LOELR 6.25 and 12.5 mg/L, respectively.

Total Organic Carbon (TOC) analysis of the WAFs containing no algal cells was conducted at 0 and 72 hours and showed measured concentrations to range from 6.39 to 53.99 mg C/L at 0 hours and from 4.62 to 52.55 mg C/L 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.

As a result of the EL50 value, in conjunction with the substance's physico-chemical properties, the test material requires classification for being hazardous to the aqueous environment and as such is categorised as Chronic Category 3 in accordance with EU criteria.