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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 exposed to the test item 1,3 – Diethyl-2-thiourea for a duration of 72 hours was assessed according to the OECD Guideline 201 and GLP requirements. ErC50 was determined: ErC50-72h=310 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:
310 mg/L
EC10 or NOEC for freshwater algae:
73 mg/L

Additional 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 1,3 – Diethyl-2-thiourea for a duration of 72 hours was assessed according to the OECD Guideline 201.

 

Algae were exposed to 500 to 50 mg/L 1,3 – Diethyl-2-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. It was possible to determine No Observable Effect Concentrations (NOEC). The results were as follows:

Endpoint

EC50-72h, mg/L (95% CI)

NOEC, mg/L

Cell growth – Biomass (b)

 

200 (150 – 270)

73

Growth rate – Cell multiplication (r)

 

310 (230 – 470)

73

  CI: confidence intreval