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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

EC50(72h)= 3.7mg/L, NOEC(growth rate)= 0.069 mg/L, JME 2005
EC50(72h)= 4.94mg/L, Pseudokirchnerella subcapitata, Aruoja 2011

Key value for chemical safety assessment

EC50 for freshwater algae:
3.7 mg/L
EC10 or NOEC for freshwater algae:
0.069 mg/L

Additional information

Amongst the six studies available in the literature four were not conducted following standard guidelines, with a short duration of exposure: Cronin 2004 (15 minutes exposure), Knie 1983 (4 hours exposure), Chen 2007 and Wang 2007 (48 hours exposure). As a consequence, these data were discarded.

Aruoja (2011) carried out a study following recent guidelines, where Pseudokirchnerella subcapitata algae were incubated in glass scintillation vials with the test item during 72 hours at 24 ± 1 °C and pH 8.0. All assays were run twice, all samples in duplicate with eight controls. The toxicity to aquatic algae was reported as EC50(72h)= 4.94 mg/L, 95 % CL= 4.74 - 5.57. However, it is unclear if the result is based on growth rate of biomass, and no NOEC was reported.

JME (2005) performed a study according to recent guidelines and under GLP. The report was unvailable and the results were extracted from a secondary source. The toxicity to aquatic algea and cyanobacteria was reported as EC50(72h)= 3.7 mg/L and NOEC = 0.069 mg/L.

The result EC50=3.7mg/L from JME (2005) were selected for risk assessment and classification purposes, because they should be the most reliable (modern guideline, GLP), the results unambiguously refer to growth rate and the value is the most conservative. In accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.2, the available data is considered reliable and adequate for the purposes of risk assessment, classification and labelling, based on a weight of evidence.

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