2,4-dichlorobenzyl alcohol

Toxicity to aquatic algae and cyanobacteria

Description of key information

The toxicity of the test substance to the freshwater alga Desmodesmus subspicatus was determined in a study (BASF SE, 01/0492/60/1, 2002) according to the principles of OECD 201 (1984) under GLP conditions. The following effect concentrations (mg/L) were obtained after 72-h based on nominal concentration: The 72-hour ErC50 value was determined to be 37 mg test item/L. The 72-hour NOErC was determined to be 12.5 mg/L and the associated 72-hour ErC10 was determined to be 22.1 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

37 mg/L

EC10 or NOEC for freshwater algae:

22.1 mg/L

Additional information

The toxicity of the test substance to the freshwater alga Desmodesmus subspicatus was determined in a study (BASF SE, 01/0492/60/1, 2002) according to the principles of OECD 201 (1984) and according to the Directive 92/69/EEC, Annex V, Part C.3. (1992) under GLP conditions. The aim of the study was to assess the effects on growth rate and the effect on the development of biomass over a period of 72 hours. The study was conducted under static conditions. This study encompassed 6 treatment groups with three replicates per test concentration and three replicates for the control. At test start 100 mL of the test concentrations were inoculated with 290 000 algal cells per mL test medium and defined volumes of the algal suspensions were sampled after 0, 24, 48 and 72 hours for determination of cell densities by fluorescence measurements (wavelength of 435 nm). The nominal test concentrations of the test substance were 0 (control), 0.39, 0.78, 1.56, 3.13, 6.25, 12.5, 25, 50 and 100 mg/L. The concentration control analysis were performed with test solutions of the following nominal concentrations of the test substance (mg/L): 0.39, 6.25 and 100 mg/L. The measured concentrations were determined to be < 0.1, 0.37, 5.75 and 88.3 mg/L (mean values). The analytical results yielded 80 % or higher recoveries; they varied between 88 and 95 % of the nominal concentrations at test initiation and between 89 to 95 % at test termination. Therefore the results were based on nominal concentrations of the test substance. A positive control with potassium dichromate was performed. The EbC50 of the control substance potassium dichromate was determined to be 0.5 mg/L after 72 hours. The cell multiplication factor in the untreated control was after 72 hours was determined to be 113-fold. There was no variation of the pH-values within the test period of 72 h about more than 2 units in the control. Therefore the validity criteria were met and the test was valid. The following effect concentrations (mg/L) were obtained after 72-h based on nominal concentration: The 72-hour ErC50 value was determined to be 37 mg test item/L and the 72-hour EbC50 was determined to be 28 mg test item/L. The 72-hour NOErC and the 72-hour NOEbC were determined to be 12.5 mg/L and the associated 72 -hour LOErC and LOEbC were determined to be 25 mg/L. The 72-hour ErC10 value was determined to be 22.1 mg/L and the associated 72-hour EbC10 was determined to be 15.6 mg/L.