3,3'-[butane-1,4-diylbis(oxy)]bispropanamine

Toxicity to aquatic algae and cyanobacteria

Description of key information

The substance is with high probability is acutelly not harmfull to aquatic algae and cyanobacteria.

Key value for chemical safety assessment

EC50 for freshwater algae:

500 mg/L

EC10 or NOEC for freshwater algae:

31.3 mg/L

Additional information

No experimental data are available for 3,3'-[butane-1,4-diylbis(oxy)]bispropanamine (CAS 7300 -34 -7). Read across is made from the analogue substance 3,3'-oxybis(ethyleneoxy)bis(propylamine) (CAS 4246 -51 -9).

An algae growth inhibition study was performed with 3,3'-oxybis(ethyleneoxy)bis(propylamine) according to the German Industrial Standard DIN 38412, Part 9 using Desmodesmus subspicatus (BASF AG, 1990; report no. 2/0505/8). The study was performed using not pH-adjusted test solutions (3.9, 7.8, 15.625, 31.25, 62.5, 125, 250 and 500 mg/L). As the test substance causes a pH-shift to more alkaline conditions with increasing test substance concentrations, two test concentrations along with the highest test concentration were also tested after pH-adjustment (15.625, 125 and 500 mg/L). The test solutions without pH-adjustment showed initial pH values between 8.62 and 10.25. However, the acceptable pH range for algae is given in the OECD TG 201 as pH 6.6 to 9.6. This pH range is only kept in the three lowest test concentrations (≤ 15.625 mg/L), while the other test solutions showed initial pH values above 9.22. After 72 hours, the pH shifted to acceptable levels in the treatments.

The concentrations were not analytically verified. However, the test concentrations are assumed to be stable over the exposure period based on a sufficient water solubility, a low Henry's Law constant (7.86E-8 Pa*m³/mol, calc., see IUCLID Ch. 5.4.2) and a low adsorption potential (log Kow = -2.5, meas., see IUCLID Ch.4.7; log Koc = 1.48, calc., see IUCLID Ch. 5.4.1).

The report did not provide estimates of the EC10 and EC20 for the response variables evaluated as part of the original study. Consequently, the data generated have been re-analyzed in an attempt to provide these values.

The ecotoxicological endpoints were re-calculated using the program ToxRatPro (v2.09, 2008). Regarding the validity criteria, the factor of cell number measured in the control between 0 and 72 h was 40.8, which is > 16. The mean coefficient of variation of sectional growth rates calculated for the individual control replicates was not higher than 35 % (7.6 %). The coefficient of variation of average specific growth rates in control cultures was 1.1 % after 72 h, which is < 7 %. Overall, it can be concluded that the test fulfils the validity criteria and, therefore, it is considered to be valid. The statistical re-analysis was performed using not pH-adjusted test solutions (8 test item concentrations) and pH-adjusted test solutions (3 test item concentrations)

The statistical re-analysis revealed that the mean inhibition of growth rate in the not pH-adjusted solutions ranged between 1.1 and 43% after 72 hours. Mean inhibition of growth rate in the pH-adjusted solutions after 72 hours was between 14.5 and 40.1%. The mean inhibition of growth rate after 72 hours in the highest test concentrations of both pH-adjusted and not pH-adjusted treatments was 40.1 and 36% respectively. Therefore, it can be concluded, the 72-h EC50 value is higher than the highest test concentration of 500 mg/L in pH-adjusted and not pH-adjusted solutions. The calculated 72-h EC10 at environmentally relevant pH is not considered to be reliable due to a small amount of the test item treatments. Therefore, for the long-term ecotoxicity assessment the 72-h ErC10 value of 31.3 mg/L was used (not pH-adjusted).

Therefore, it can be concluded that based on the available read-across experimental data from the structurally similar substance (CAS 4246-51-9), DODA (CAS 7300-34-7) is with high probability acutely not harmful for aquatic algae.