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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

A study according to OECD 201 was performed to assess the effect of the test item on the growth of the green alga Pseudokirchneriella subcapitata. Following a preliminary range-finding test, Pseudokirchneriella subcapitata was exposed to an aqueous solution of the test item at concentrations 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. The test item was known to be volatile and hence testing was conducted in completely filled, stoppered test vessels in order to minimise possible losses due to volatilisation. Following the recommendations of published data (Hermanet al1990) in order to prevent inhibition of growth due to the restriction of gaseous exchange, additional sodium bicarbonate was added to the culture medium to provide a source of carbon dioxide for algal growth.
Exposure of Pseudokirchneriella subcapitata to the test item gave the following results: 72h-ErC50 16 mg/L and NOECr 3.2 mg/L.
Analysis of the test preparations at 0 and 72 hours showed measured test concentrations to range from 81% to 110% of nominal and so the results are based on nominal test concentrations only.
Due to the volatile nature of the test item, additional test replicates were prepared at 0 hours and incubated alongside the test to provide samples for unopened vessel analysis at 72 hours. Analysis of these preparations showed measured test concentrations to range from 78% to 108% of nominal.

Key value for chemical safety assessment

EC50 for freshwater algae:
16 mg/L
EC10 or NOEC for freshwater algae:
3.2 mg/L

Additional information