Amines, C16-18 (even numbered)-alkyl , salts with phosphoric acid, mono- and di-C16-18 (even numbered) alkyl esters

Short-term toxicity to fish

Description of key information

The registered substance is an Alkyl phosphate and stearyl amine salts (EC = 952-252-4) are mainly composed by primary alkylamines (CAS 90640-32-7, UVCB) and Phosphoric acid, octadecyl ester (CAS 39471-52-8, Multi-Constituent). Both elements present a long hydrogenated (saturated) carbon chain combination mono/diester phosphate with primary amine (16 to 18 carbon atoms). 

 

Regarding the other part of the salt, the fish acute was waived because the phosphoric acid, octadecyl ester (CAS 39471-52-8) the multiconstituent did not show any chronic effects on fish according a TG OECD 210 and GLP. The No Observed Effect Loading Rate was 100 mg/L (WAF).

 

Regarding the primary alkylamines (CAS 90640-32-7), the key value for this endpoint was obtained with Amines, coco alkyl and corresponds to an LC50 of 0.84 mg/L for fish. The key value is then converted to the corresponding value of the salt, resulting to an LC50 of about 2,9 mg/L (MW of Amines, coco alkyl = 194-204 g/mol, MW of the registered substance = 710,7 g/mol = 256 g/mol Primary alkylamine salt + 454,7 g/mol Phosphoric acid, octadecyl ester).

 

Therefore, it is relevant to use the available ecotoxicity data of the primary alkylamine by a read-across approach for the registered salt.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

2.92 mg/L

Additional information

Data available for primary alkyl amines:

Most of the tests available with fish were conducted in the end of the 1980s. Since the concentrations were not analytically verified, the reliability of the results is limited. Hence, most of the tests were considered to be valid with restrictions.

The available data reveal an increasing toxicity with raising chain length. The only exception is stearylamine (C18) where only a summary test report is available which indicates a slight drop of toxicity.

96h-LC50 reported for fish is 0.11 mg/l (nominal) for oleylamine (C18). In this study the short-term toxicity to Pimephales promelas was examined by Mark (1995) in the presence and absence of humic acid using a static water test system according to the OECD Guideline 203 (1984). Fish were exposed at about 21°C for 96 h in reconstituted freshwater (pH 7.7-8.3, oxygen content 9.0-8.3 mg/l). Since the test material was insoluble in water, stock dispersions (approx. 0.1 g/l) were freshly prepared by ultrasonic treatment before each test was started. During each dosing step, the stock solutions were stirred to prevent any inhomogeneity of the stock solutions. At the start of the tests, all test solutions were clear and homogeneous. Five test concentrations in the nominal concentration range between 0.05 and 0.49 mg/l were employed. During all tests the test substance content decreased strongly showing a rather wide spread of the recovery rates. The test protocol explained this by the following factors:

-        Adsorption onto the walls of test vessels or – especially - on other surfaces (such like the surfaces of the test animals).

-        Reaction with organic materials (humic acid).

-        Humic acid might act as an emulsifier and hence is likely to influence the extraction process during the chemical analysis (HPLC).

-        An incomplete water removal during the analytical procedure causes disturbances of the chemical analysis.

However, based on nominal concentrations a 96 h-LC50 of 0.11 mg/l was derived from this study. When taking the results of the chemical analysis into account by using the mean recovery rate (about 51%) as the actual test concentration throughout the test, the 96 h-LC50 can be calculated as 0.06 mg/l.

From this study it can also be concluded that humic acid clearly has an effect on bioavailability of oleylamine for fish. As compared to the test results without humic acid, the addition of 10 mg/l humic acid resulted in an approximate 14-fold decrease the calculated LC50 based on nominal concentrations and about 20-fold based on analytically determined concentrations.

Additional acute fish 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 ecotoxicty result. For risk assessment purposes these ecotoxicity results can be compared with the total or bulk concentration in surface water. The lowest LC50_96h was obtained with Amines, coco alkyl and was 0.84 mg/L.