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EC number: 274-713-2 | CAS number: 70643-20-8
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
In this study 2,4-diaminophenoxyethanol sulphate dihydrate was found to inhibit the growth of the freshwater green alga Pseudokirchneriella subcapitata after 72 hours with the following effect values (geometric mean measured concentrations). The EC50 values with 95% confidence intervals for inhibition of specific growth rate (ErC50) and yield (EyC50) after 72 hours were 36.5 (34.6 - 38.2) mg test item/L and 10.2 (7.17 - 15.3) mg test item/L, respectively. The NOEC values for inhibition of specific growth rate and yield after 72 hours were 8.56 mg test item/L and 0.913 mg test item/L, respectively.
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 10.2 mg/L
- EC10 or NOEC for freshwater algae:
- 1.55 mg/L
Additional information
The toxicity of 2,4 -diaminophenoxyethanol sulphate dihydrate to the unicellular freshwater green alga Pseudokirchneriella subcapitata was determined according to the principles of OECD guideline 201. The aim of the study was to assess the effects on growth rate and yield over a period of 72 hours. The study was conducted under static conditions with an initial cell density of 5X10E3 cells/mL. Seven nominal concentrations were tested in a geometrical series : 0.100 - 0.320 - 1.00 - 3.20 - 10.0 - 32.0 - 100 mg/L corresponding to geometric mean measured concentrations of 0.0729 - 0.299 - 0.913 - 2.94 - 8.56 - 27.7 - 53.7 mg/L. Three replicates were tested for the test item concentrations and six replicates for the control. Environmental conditions were determined to be within the acceptable limits. The test item concentrations were analysed at all concentration levels at test start and test end via HPLC analysis. The measured concentrations at test start were in the range of 102 to 118% of the nominal values. Recovery rates at the end of the test were in the range of 28 to 82% of the nominal values, except the recovery of the lowest test item concentration which was below the limit of quantification. The EC50 values with 95% confidence intervals for inhibition of specific growth rate (ErC50) and yield (EyC50) after 72 hours were 36.5 (34.6 - 38.2) mg test item/L and 10.2 (7.17 - 15.3) mg test item/L, respectively. The NOEC values for inhibition of specific growth rate and yield after 72 hours were 8.56 mg test item/L and 0.913 mg test item/L, respectively.
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