3-aminopropyldimethylamine

Toxicity to aquatic algae and cyanobacteria

Description of key information

The substance is acutely harmful to aquatic algae.

Key value for chemical safety assessment

EC50 for freshwater algae:

34 mg/L

EC10 or NOEC for freshwater algae:

26 mg/L

Additional information

The effects of 3 -aminopropyldimethylamine (DMAPA, CAS 109-55-7) on freshwater algae have been assessed using data from a growth inhibition test with DMAPA according to DIN 38412-9 (BASF AG, 1987) and read-across data from three tests with the structurally similar substance 3 -aminopropyldiethylamine (DEAPA, CAS 104-78-9).

In a static growth inhibition test, the freshwater algaePseudokirchneriella subcapitatawas exposed to the read-across substance 3-aminopropyldiethylamine (CAS 104 -78 -9) for 72 hours according to OECD 201 and under GLP conditions. The algae were exposed to nominal concentrations between 4.77 and 50 mg/L. The test item concentrations were analytically verified and the final concentrations were maintained within the designated limit of 80% of the initial concentrations in non-inoculated flasks. Therefore, the effect concentrations and NOEC have been calculated using the nominal concentrations. The 72-h ErC50 and the 72-h NOEC were determined to be 34 and 19.53 mg/L, respectively. The 72-h ErC10 was determined to be 26 mg/L (Arkema, 2000, report no.: 57/99/A. The pH values of the test solutions were not adjusted. They were in acceptable range of 7.6 to 9.3 at the beginning of the test and 8.0 to 9.4 after 72 hours of exposure. Therefore, an effect of the pH level on the toxicity of the test substance can be excluded. The validity criteria of the study were fulfilled. The results were selected as key values for the further risk assessment.

In addition, acute toxicity of the read-across substance toDesmodesmus subspicatuswas investigated according to German Industrial Standard DIN 38412-9. The 72-h ErC50 was determined to be between 100 and 150 mg/L using not pH-adjusted test solutions (BASF AG, 1990, report no.: 02/90/134). The concentrations were not measured in the vessels during the test but the substance is expected to be stable in water as shown in the study mentioned above. Another test with the source substance was conducted according to German Industrial Standard DIN 38412-9. But the stock solution was neutralised with hydrochloric acid to pH 7. In this study, the 72-h ErC10 and the 72-h ErC50 were determined to be 3.45 g/L and 7.12 g/L, respectively (BASF AG, 1990, report no.: 04/90/154). The first two studies were performed without adjustment of the pH as no preferred pH range is described in the guideline. However, in the third study the pH was adjusted, leading to clearly higher effect values. The result of the study suggests that the toxicity of the source substance 3-aminopropyldiethylamine is related to the increase of the medium pH but not to a specific mode of toxic action.

For the target substance 3-aminopropyldimethylamine (CAS 109-55-7), two studies are available, which further support the result of the key study. The 72-h static test withDesmodesmus subspicatuswas performed according to the German Industrial Standard Test Guideline DIN 38412-9. The results were recalculated using ToxRatPro v2.09. The concentrations were not analytically verified but 3-aminopropyldimethylamine is expected to be stable in water due to the high water solubility, the low Henry´s law constant and the low adsorption potential (log Kow and log Koc < 3) of the substance. The re-evaluation showed that the validity criteria of the recent guideline OECD 201 were not fully met, but are in agreement with the above-mentioned results of the structurally similar substance 3-aminopropyldiethylamine. After 72 hours an ErC50 of 64.3 mg/L and an ErC10 of 48.4 mg/L were determined, related to nominal concentration (BASF AG, 1987, report no.: 2/0556/87; BASF SE, 2009).

 

In an additional marine study performed with 3 -aminopropyldimethylamine according to ISO 10253 using Skeletonema costatum as test species a 72-h ErC50 of 55 mg/L was determined, based on nominal test concentrations (Eide-Haugmo, 2009, 2012).

 

Based on the available results, it can be concluded that DMAPA is acutely harmful to aquatic algae.