Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

In a 7-day algal growth inhibition test with Anabaena flos-aquae EC25 and EC50 values of 7.3 and 11.7 mg/L were determined, respectively. Anabaena flos-aquae was the most sensitive species tested.

Key value for chemical safety assessment

Additional information

Freshwater

Key study (American Cyanamid Company, 981 -86 -175, 1987)

A 7-day static freshwater test with cyanobacteria Anabaena flos-aquae was conducted equivalent to OECD guideline 201. Cyanobacteria were exposed to the test substance at nominal concentrations of 0, 5.6, 10, 18, 32, 56 and 100 mg/L. These nominal concentrations corresponds to the following mean measured concentrations: <0.02, 5.26, 9.6, 17.6, 30.2, 55.1 and 103 mg/L. Biomass was determined by cell counts on day 2, 3, 4 and 7. Percent inhibition or stimulation, relative to the control, was calculated for each concentration based upon the mean standing crop in cells/mL at seven days. Effects ranged from 4.8% stimulation to 99.4% inhibition. The 7-day EC25 was 7.3 mg/L (95% CI <0.0001 - 51.4 mg/L) and the 7-day EC50 was 11.7 mg/L (95% CI <0.0001 - 105.5 mg/L), based on mean measured concentrations. 

Supporting study (American Cyanamid, Company, 981-86-172, 1987)

An additional 7-day freshwater test with freshwater algae Pseudokirchneriella subcapitata performed equivalent to OECD guideline 201 is available. The algae was exposed to nominal test substance concentrations of 0, 10, 18, 32, 56, and 100 mg/L. These nominal concentrations corresponds to the mean measured concentrations of <0.5, 9.4, 16.8, 30.8, 50.9 and 101.2 mg/L. Biomass was determined by cell counts on days 2, 3, 4 and 7. Percent inhibition or stimulation, relative to the control, was calculated for each test concentration based upon the standing crop in cells/mL at seven days. The 7-day EC25 and the 7-day EC50 was determined to be 48 and 71 mg/L respectively. 

 

Supporting study (American Cyanamid, Company, 981-86-173, 1987)

An additional 7-day freshwater test with freshwater diatom Navicula pelliculosa performed equivalent to OECD guideline 201 is available. The freshwater diatom Navicula pelliculosa was exposed to nominal test substance concentrations of 0, 10, 18, 32, 56, and 100 mg/L. These nominal concentrations corresponds to the mean measured concentrations of <0.5, 8.2, 10.5, 23.5, 55.8 and 41.0 mg/L (the mean measured concentration for the highest nominal concentration, 100 mg/L, was actually lower than the mean measured concentration for the 56 mg/L nominal concentration). Biomass was determined by cell counts on days 2, 3, 4 and 7. Percent inhibition or stimulation, relative to the control, was calculated for each test concentration based upon the standing crop in cells/mL at seven days. All test concentrations were somewhat stimulatory to pelliculosa. Therefore, EC values could not be determined from the data. The 7-day EC25 and the 7-day EC50 would be greater than the highest mean measured test concentration of the test substance, 55.8 mg/L. 

 

Marine water

Supporting study (American Cyanamid Company, 981-86-174, 1987)

In a 7-day study with the marine diatom Skeletonema costatum is available. Skeletonema costatum was exposed to the nominal test substance concentrations 0, 10, 18, 32, 56 and 100 mg/L, which corresponds to the mean measured concentrations of <1, 8.9, 15.9, 28.7, 47.4 and 90.5 mg/L. Biomass was determined by cell counts on day 2, 3, 4 and 7. Percent inhibition, relative to the control, was calculated for each concentration based upon the mean standing crop in cells/mL at seven days. Effects ranging from 0.7% to 54.0% inhibition were observed. The 7-day EC25 was 42.2 mg/L and the 7-day EC50 was 85.5 mg/L, based on mean measured test concentrations.

 

Conclusion:

Anabaena flos-aquae was the most sensitive species of the three tested algae species with an EC25 and EC50 of 7.3 and 11.7 mg/L, respectively.