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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The 96 hour EL50 (presented as “EC50” in report) for both 'cells per mL' and 'growth rate' is >1,000 mg/L nominal WAF loading rate. The 96 hour NOELR (presented as “NOEC” in report) is 360 mg/L nominal WAF loading rate as calculated using the number of cells per mL, and 220 mg/L nominal WAF loading rate as calculated using average specific growth rate.
Test results reported in original study as “effect concentrations (EC)” and “no observed effect concentrations (NOEC)” are reported in this summary as “effect loading (EL)” and “no observed effect loading rate (NOELR)”, respectively, because test results are based on nominal WAF loading rates.

Key value for chemical safety assessment

EC50 for freshwater algae:
1 000 mg/L
EC10 or NOEC for freshwater algae:
220 mg/L

Additional information

In the key study, the acute toxicity of the water accommodated fraction (WAF) of five mixtures of the test material and water to the Selenastrum capricornutum, was investigated during a study conducted at T.R. Wilbury Laboratories, Inc. The test, which was designed to determine the toxicity of the test substance, was performed from November 8 to 12, 1996 and was conducted according to OECD Guideline 201 (Alga, Growth Inhibition Test).

This study is presented as the key information as the reliability rating for this study is 1, according to the criteria of Klimisch, 1997, and this study was conducted most recently and therefore is considered the most reliable study.

There is also a supporting study available:

- The T.J. Ward, 1993 study (T.R. Wilbury Laboratories, Inc., report number: 73-CM-608) was not considered the key study as it was conducted less recently than the above key study. The study was conducted according to the OECD Guideline 201 (Alga, Growth Inhibition Test) and GLP and was considered to have a reliability rating of 1, according to the criteria of Klimisch, 1997.

Nominal concentrations: 72 & 96-h EL50 >1,000 mg/L and 72 & 96-h NOELR = 1000 mg/L based on both growth rate and biomass measurements.