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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The determination of the growth inhibition of the freshwater algae Pseudokirchneriella subcapitata (previously known as Raphidocelis subcapitata and Selenastrum capricornutum) exposed to the test item N,N’- Diphenyl Thiourea for a duration of 72 hours was assessed according to the OECD Guideline 201.
 
Algae were exposed to 100 to 5 mg/L of N,N’- Diphenyl Thiourea dissolved in dilution water. The toxic effect measured during the assay was the inhibition of cellular multiplication over a time period of 72 hours.
The concentrations of test item causing a 50 % reduction in biomass (EbC50) and in growth rate (ErC50) were estimated respectively at 7.8 mg/l and 15 mg/l.

Key value for chemical safety assessment

EC50 for freshwater algae:
14 mg/L
EC10 or NOEC for freshwater algae:
4.7 mg/L

Additional information

The determination of the growth inhibition of the freshwater algaePseudokirchneriella subcapitata(previously known asRaphidocelis subcapitataandSelenastrum capricornutum) exposed to the test item N,N’- Diphenyl Thiourea for a duration of 72 hours was assessed according to the OECD Guideline 201.

 

Algae were exposed to graded series of N,N’- Diphenyl Thiourea concentrations. Growth rate inhibition was estimated over a 3 -day period. The concentrations of test item causing 50% and 10% reduction in growth rate (ErCx) were estimated by the registrant from the raw data included in the study report with Toxrat 3.2.0. EC50 was 14 mg/L and EC10 was 4.7 mg/L for growth rate inhibition.