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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

96 h EbL50 = 5.4 mg/L, ErL50 = > 16 mg/L, NOEC = 0.5 mg/L, Pseudokichneriella subcapitata, OECD 201, EU Method C.3, EPA OPPTS 850.5400, EPA OTS 797.1050, Vryenhoef (2002)

Key value for chemical safety assessment

EC50 for freshwater algae:
16 mg/L

Additional information

The toxicity of the test material to aquatic plants was investigated in the algae Pseudokichneriella subcapitata in accordance with standardised guidelines OECD 201, EU Method C.3, EPA OPPTS 850.5400 and EPA OTS 797.1050. Following two range finding studies, the algal culture was exposed to Water Accommodated Fractions (WAFs) of the test material over a range of nominal loading rates on 0.5, 1, 2, 4, 8 and 16 mg/L for 96 hours, under constant illumination and shaking at a temperature of 24 ± 1 ºC. Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group, using a haemocytometer and light microscope. Under the conditions of the study, the effect of the test material on the growth of P. subcaptitata after an exposure period of 96 hours, gave a 96 hour EbL50 value of 5.4 mg/L loading rate WAF and a ErL50 value of greater than 16 mg/L loading rate WAF based on growth rate. The No Observed Effect Loading rate was determined to be 0.5 mg/L loading rate WAF. Total Organic Carbon (TOC) analysis of the control, 0.5 and 16 mg/L loading rate WAF test preparations was performed at 0 and 96 hours. Given the background level of carbon in the control vessels and also the low level of carbon in the test vessels, it was considered that the results gave no evidence of the presence of test material in the WAFs.