Dimethyl sebacate

Toxicity to aquatic algae and cyanobacteria

Description of key information

The effect of the test item on the growth of Pseudokirchneriella subcapitata has been investigated according to OECD 201 guideline over a 72-Hour period and gave the following results based on the time-weighted mean measured test concentrations: 
Inhibition of Growth Rate
ErC10 (0 - 72 h) : 0.49 mg/L
ErC50 (0 - 72 h) : 1.5 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

1.5 mg/L

EC10 or NOEC for freshwater algae:

0.49 mg/L

Additional information

A study was performed to assess the effect of the test item on the growth of the green alga Pseudokirchneriella subcapitata. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) No 761/2009.

 

Following a preliminary range-finding test, Pseudokirchneriella subcapitata was exposed to an aqueous solution of the test item at concentrations of 1.0, 3.2, 10, 32 and 100 mg/L (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1 °C. Samples of the algal populations were removed daily and cell concentrations determined for each control and treatment group, using a Coulter®Multisizer Particle Counter.

Chemical analysis of the test preparations at 0 hours showed measured test concentrations to range from 86% to 94% of nominal. Given that chemical analysis of the range-finding test preparations had shown a decline in measured test concentration occurred over the test period, additional test samples were prepared at 0 hours and incubated alongside the test to provide samples for analysis at 24 and 48 hours. Analysis of the test preparations at 24 hours showed measured test concentrations to range from less than the limit of quantitation (LOQ) of the analytical method employed (which was determined to be 0.0049 mg/L) at 1.0 mg/L through to 104% of nominal at 100 mg/L. Measured concentrations in the range of less than the LOQ at 1.0, 3.2 and 10 mg/L through to 87% of nominal at 100 mg/L were observed at 48 hours whilst concentrations in the range of less than the LOQ at 1.0, 3.2, 10 and 32 mg/L through to 26% of nominal at 100 mg/L were observed at 72 hours

 

Given this decline in measured test concentrations it was considered justifiable to base the results on the time-weighted mean measured test concentrations in order to give a "worst case" analysis of the data. Exposure of Pseudokirchneriella subcapitata to the test item gave the following results based on the time-weighted mean measured test concentrations:

 

Inhibition of Growth Rate

ErC10(0 - 72 h) : 0.49 mg/L

ErC20(0 - 72 h) : 0.71 mg/L

ErC50(0 - 72 h) : 1.5 mg/L