C16-18-(even numbered)-alkyl fatty acid, compound with C16-18-(even numbered)-alkylamine

Short-term toxicity to aquatic invertebrates

Description of key information

The key value for this endpoint was obtained with Amines, coco alkyl and corresponds to an EC50 of 0.32 mg/L for daphnia.
These data have been used as read-across for the registered substance. They are then converted to the corresponding value of the salt, resulting to an EC50 of about 0.88 mg/L (MW of Amines, coco alkyl = 194-204 g/mol, MW of the registered substance = 547.5 g/mol (263 g/mol hydrogenated tallow alkyl amine + 284.5 g/mol acid stearic)).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.88 mg/L

Additional information

Data available for primary alkyl amines:

Regarding the acute toxicity data towards Daphnia magna, a dependence on the chain length of primary fatty amines cannot be stated.

A study was conducted with oleylamine (Akzo Nobel, 1995a) according to the OECD Guideline 202 (1984) in the presence or absence of humic acid. Daphnia were exposed to five test concentrations in the nominal concentration range between 0.006 and 0.09 mg/l in a static system for 48 h at a temperature of 19.1-19.7°C and a pH of 8.0-8.2.For the preparation of the stock dispersions (0.1 g/l) ultrasonic treatment was used and during each dosing step the stock solutions were stirred. At the start of the tests, all test solutions were clear and homogeneous. Again, during all tests the test substance content (measured at 0 hand 48 h via HPLC) decreased strongly showing a wide spread of the recovery rates(test without humic acid: recovery 48-118%, mean value 81%; test with 10 mg/l humic acid: recovery 23-98%, mean value 56%; test with 20 mg/l humic acid: recovery 0-23%, mean value 7.4%). Due to this, no calculations based on measured concentrations were performed.

Based on nominal concentrations the 48h-EC50 values were calculated as 0.011 mg/l (without humic acid), 0.43 mg/l (10 mg/l humic acid) and 0.56 mg/l (20 mg/l humic acid). Compared to the test results without humic acid, the addition of 10 mg/l humic acid resulted in an approximate 40-fold higher EC50.

Additionally, studies using different species of invertebrates describing effects of pH, temperature and stage of insect development are reported for different primary fatty amines. An enhancement of toxicity of octylamine and decylamine on larval mortality of Elminius modestus at higher pH and lower temperature is described by Christie & Crisp (1966). Larvae of Culex pipiens quinquefasciatus are more sensitive to primary fatty amines than pupae (Mulla 1967 a, b) and Aedes aegypti (Cline 1972). Larvae and pupae of Anopheles sp. and Aedes sp. are of similar sensivity to oleylamine and coco alkyl amines (Mulla 1970).

Additional acute daphnia tests in natural river water (River Boehme) with a DOC of 6.3 mg/l and suspended matter of 16.7 mg/L (Noack, 2006a & b) were carried out. In river water the Primary alkyl amines which are cationic surfactants at pH relevant in the environment, are either dissolved in water or sorbed to dissolved and particulate matter. No sorption to glass ware occurs under these conditions which were confirmed by measurements. This ensures reliable as well as reproducible results. Ecotoxicity is mitigated due to sorption but this kind of tests at least ensures that all added test substance is present in the test system and available for the exposure of the organism in dissolved or sorbed form. Mitigation can be taken into account by a factor of 10 applied to the ecotoxicity result. For risk assessment purposes these ecotoxicity results can be compared with the total or bulk concentration in surface water.