C16-18-(even numbered, C18-unsaturated)-alkylamines acetates

Toxicity to aquatic algae and cyanobacteria

Description of key information

The lowest effect values (nominal) for aquatic algae have been found for coco alkyl amine (96h-EBC50 = 0.0008 mg/L, 96-NOEC = 0.0002 mg/L), hydrogenated tallow alkyl amine (96h-EBC50 = 0.012 mg/L, 96-NOEC = 0.008 mg/L) and tallow alkyl amine (96h-EBC50 = 0.007 mg/L, 96-NOEC = 0.002 mg/L). These studies were conducted according to the OECD Guideline 201 (1984) with Scenedesmus subspicatus as test organism by Berol Nobel (1991c-e):

For the preparation of the stock solutions solubilizer were used. The test vessels were exposed to the test substance overnight to allow pre-adsorption onto the surface of the glassware. At the start of the tests the glassware was rinsed with the test solution to be tested and then refilled with the fresh test solution. Samples for measurement of growth were taken every 24 hours and the absorbance was determined with a photometer at 665 nm. The cell densities of the control cultures at initiation and at termination were measured by direct counting. As no analytical measurements were performed, test results were based on nominal concentrations.

The actual cell concentration in the control after 72 hours is not given in the test reports but estimation can be made by plotting the absorbance against cell number of the 0 and 96 h control values and assuming that the calibration was linear up to the maximum absorbance used. This estimation leads to conclusion that in the studies with coco alkyl amine and hydrogenated tallow alkyl amine the increase of cell concentration in the control was to low (well below factor 16). For this reason and due to the missing analytical data at very low effect concentration levels, the test results of Berol Nobel (1991) are regarded as not suitable for effects assessment purposes.

Other EC50-values reported for primary fatty amines are in the nominal concentration range between 0.04 mg/l (oleylamine, tested in synthetic medium) and 0.46 mg/l (oleylamine, tested in natural river water).

For coco alkyl amine, tallow alkyl amine and oleylamine test results are available, which were determined in natural, unfiltered river water (Noack 2002). Studies were conducted according to the OECD Guideline 201 (1984) in a static test system (temperature approx. 23°C, pH approx. 8) with Desmodesmus subspicatus (Scenedesmus subspicatus) as test organism. A pre-treatment of test vessels was not performed. Water of the river “Böhme” was used as dilution water. Exposure concentrations were analytically verified at 0 and 72 h in the highest tested concentration using GC/MS-analysis. Due to variations in the content of suspended matter and the adsorbing properties of the test substances, decreasing test concentrations associated with strongly varying recovery rates were observed (coco alkyl amine: 0-120%, mean 60%; tallow alkyl amine: 73-23%, mean 48%; oleylamine: 72-0%, mean 36%). Test results were therefore based on nominal concentrations. Referring to nominal concentrations for coco alkyl amine a 72h-ERC50 of 0.16 mg/l (72h-NOEC of 0.06 mg/L), for tallow alkyl amine a 72h-ERC50 of 0.39 mg/L (72h-NOEC of 0.125 mg/L) and for oleylamine a 72h-ERC50 of 0.46 mg/L (72h-NOEC of 0.15 mg/L) was determined indicating a slight decrease of toxicity with raising chain length.

After the algae have been exposed for 72 hours recovery of the algae has been observed upto 1 mg/L for the coco, 2.5 mg/L for the oleyl and 4 mg/L for the C16-18 amine showing that under environmental conditions the effect on algae is reversible (algaestatic)

Key value for chemical safety assessment

EC50 for freshwater algae:

0.16 mg/L

EC10 or NOEC for freshwater algae:

0.06 mg/L