Cycloheptapentylose

Toxicity to aquatic algae and cyanobacteria

Description of key information

The NOEC for named parameters is 32 mg/L, the LOEC is 100 mg test item/L. 

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

32 mg/L

Additional information

The toxicity of .beta.-Cyclodextrin (100.6% pure HPLC) to Desmodesmus subspicatus was assed in an Algal Growth Inhibition Test according to OECD Guideline 201. This study encompassed 8 treatment groups (7 dose rates of the test item of 100, 32, 10, 3.2, 1.0, 0.32 and 0.1 mg test item/L and a control) with three replicates per test concentration and six replicates for the control. At test start 50 ml Erlenmeyer flasks were inoculated with 5000 algal cells per ml test medium and defined volumes of the algal suspensions were sampled after 24, 48 and 72 hours for determination of cell densities by spectrophotometrical measurement. The analysis of the test item concentration in the test media was done by determination of TOC content as sum parameter since the test item is stable in aqueous solution and not volatile. During the test period test item concentrations were measured in the range from 83 % to 89 % of the nominal values (for the test concentrations of nominal 32 and 100 mg test item/L). Under the test conditions the test item was sufficiently stable during the test period of 72 hours. Therefore, all reported results are related to nominal concentrations of the test item. The 72-hours EC50 value for the growth rate, biomass and yield could not be calculated due to low effects of .beta.-Cyclodextrin and is supposed to be higher than 100 mg test item/L (the highest concentration tested). The NOEC for named parameters is 32 mg/L, the LOEC is 100 mg test item/L showing a reduction in growth rate of 6.8% , a reduction in yield of 28.6% and a reduction of 34.6% in biomass compared to the control group.