Amines, C11-C13 (linear and branched) alkyl

Toxicity to aquatic algae and cyanobacteria

Description of key information

Acutely very toxic for algae

Key value for chemical safety assessment

EC50 for freshwater algae:

0.015 mg/L

EC50 for marine water algae:

0.2 mg/L

EC10 or NOEC for freshwater algae:

0.003 mg/L

Additional information

Tridecylamine, branched and linear (CAS 86089-17-0) is a mixture of C13 isomers (branched and linear; 99.8 -100%).

1 -Tridecanamine (CAS 2869 -34-3 = linear isomer) was selected as a representative C13 substance due t its expected higher toxicity (see Summary of IUCLID Ch. 6.1). Therefore, the assessment of the toxicity of the substance to fish was based on the available experimental data of the compound itself and on the read-across data for the source chemical CAS 2869-34-3.

The assessment of the toxicity to algae of TDA, b+l is based on the experimental data of the substance itself and the experimental from the read-across to the structurally similar substance 1 –Tridecanamine (CAS 2869 -34 -3). Toxicity to freshwater algae is based on information for TDA, b+l, while toxicity to marine algae is based on two tests with the structurally similar 1-tridecanamine (CAS 2869-34-3).

Freshwater algae:

Several algae toxicity studies with Desmodesmus subspicatus are available, mainly performed at BASF AG. In some of the studies Cremophor was used as solvent. There is no evidence that the solvent influenced the toxicity of the substance. The exposure concentrations were not verified in any of the studies.

Since more than one EC50 value for the same endpoint and species is available, according to the EU-Technical Guidance Document (ECB, 2003) the geometric mean of the results can be used to calculate a 72-h ErC50 of 0.015 mg/L. In analogy to the EC50, the geometric mean was also calculated for the available five ErC10 values. The chronic effect value used for the risk assessment is 0.0032 mg/L.

Supporting information on the toxicity to algae are available from a non-GLP screening study with Rhaphidocelis subcapitata (previously named: Pseudokirchneriella subcapitata) which was conducted to study the potential mitigating effect of humic acid on the toxicity of tridecylamine, branched and linear (BASF SE, 2016; report no. 86E0391/03E011). The screening study followed a modified protocol of OECD 201 (reduced number of replicates, higher spacing factor, no concentration control analysis). Test solutions were prepared as water accomodated fractions at loading rates of 1, 10 and 100 mg test item/L (nominal). The screening test was performed to evaluate the potential of natural carbon for toxicity mitigation. Humic acid was used to simulate the carbon source. One experiment was performed without addition of humic acid, while two others were performed with addition of humic acid (Na salt) at concentrations of 3 and 10 mg/L. The ErL50 was < 1 mg/L in all three experiments. It can be concluded that there was no clear trend in the estimated EL50 values; thus, the results demonstrate no potential mitigation through humic acid on the acute toxicity of tridecylamine, branched and linear. However, due to considerable restrictions (e.g. no analytical verification of test item concentrations, the high spacing factor, low number of replicates, low number of test item concentrations), the screening study is disregarded in terms of the chemical safety assessment.

 

Marine algae:

With the marine algae species Dunaliella parva and Amphora coffeaeformis results of growth inhibition tests are available. Related to biomass at test end, the 96-h EC50 was ca. 0.2 mg/l for Dunaliella parva and ca. 0.8 mg/l for Amphora coffeaeformis (Finlay and Callow, 1996). The effect value for Dunaliella parva was selected as key study for the marine environment.

 

Based on the available experimental data for the target substance and experimental read-across data for its structural analogue, it can be concluded that tridecylamine, branched and linear (CAS 86089 -17 -0) is acutely very toxic to aquatic algae and cyanobacteria.