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

Toxicity to microorganisms

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 combinaison mono/diester phosphate with primary amine (16 to 18 carbon atoms). 

 

Regarding the other part of the salt, the Phosphoric acid, octadecyl ester (CAS 39471-52-8) the multiconstituent didn't show any effects on micro-organisms according a TG OECD 209 and GLP. The toxicity of microorganisms was measured by an EC50 of 1000 mg/L and a No observed effect concentration (NOEC) of 1000 mg/L.

 

Regarding primary alkylamine part of the salt, the key value for this endpoint was obtained with coco alkyl amine and corresponds to an EC10 of 5.5 mg/L. This data correspond to the worst case value and have been used as read-across for the registered substance.

 

The key value is then converted to the corresponding value of the salt, resulting to an EC10 of 19,1 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).

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

19.1 mg/L

Additional information

Data available for primary alkyl amines:

 

A number of tests on inhibition of respiration according to OECD Guideline 209 were conducted. An overview of the results is presented in the table below:

 

 

Table: Respiration tests according to OECD 209 [mg/l]

Substance	EC10	EC20	EC50	EC80	Remarks	Reference
Coco	5.5	7.5	14	25	Suspended with ultra-turrax	Hoechst AG (1989b)
		2.7	14.2	75.3	direct addition of TS	Hoechst AG (1992a)
Tallow	7	12	32	90		Hoechst AG (1989c)
Hydrog. tallow		214	490	>1000	direct addition of TS	Hoechst AG (1993b)
Octadecenyl		62.7	222.5	790	direct addition of TS	Hoechst AG (1992b)

The results of the respiration tests suggest that the toxicity of hydrogenated tallow amine and octadecenylamine to sewage sludge is much lower than that of coco and tallow amine. Regarding the test results with other organisms, similar toxicity of the compounds is expected. It can be assumed that the different results may be caused by different bioavailability of the test substances. As discussed earlier, bioavailability of the test substances is largely dependent on the method of preparation of the test medium, although there is no real explanation for the differences of individual tests. For the PNEC derivation, the lowest effect value observed with coco amine as test substance are used.