Polyamide wax

Endpoint summary

Additional information

The test substance has a low water solubility value according to the OECD Guidance No. 23 definition (less than 100 mg/L).

 

The substance has to be considered as a difficult substance to be tested particularly for (i) achieving exposure concentration and (ii) preparing representative media.

 

The hydrolysis study was not conducted due to the low solubility of the test substance in water (< 0.2 mg/L). In a standard screening biodegradation test (CO2 evolution test), the percentage of biodegradation of test material was determined at 6% based on TCO2 after 28 days of exposure. The test substance does not meet the readily biodegradable criterion. Calculated log Koc values for the test substance were in the 7.4 - 11.55 range; the substance is likely to be of low mobility in soils.

 

Aquatic bioaccumulation testing was not conducted due to the fact that (i) the known components of the substance (cf. boundary composition) have log Kow values higher than 13 (13.28 to 20.60) and (ii) because of the high insolubility in water of the test substance (<0.1 µg/L). As a result, bioavailability for aquatic organisms is expected to be low. Indeed, the components have molecular weights ranged between 665 and 964 g/mol and log Kow values higher than 13 (13.28, 14.41 and 20.60). According to Lipinksi et al. (1997), a substance with such properties (log Kow > 5 and MW > 500 g/mol) and more than 5 H-bond donors and 10H-bond acceptors is unlikely to cross a biological membrane in amounts sufficient to exert toxic response. Moreover, Dimitrov et al. (2005) showed that substances with log Kow values higher than 10 had BCF values significantly lower (<1000 L/kg) than the threshold of 2000 L/kg ww. 

 

The BCF values predicted on the registered UVCB's constituents by the BCFBAF v3.01 model from EPISUITE software demonstrates these assomptions (see the table below). However, modelling a BCF or BAF value would not provide reliable information since the log Kow of the substance is high (> 6.0), so that there is no longer a relationship between the log Kow and the BCF/BAF.  

 

Compound	SMILES	Molecular weight (g.mol-1)	Log Kow estimation (KOWWIN v1.68)	Experimental Log Kow (KOWWIN database)	Estimated BCF (BCFBAF v 3.01), L/kg ww	Experimental BCF (BCFBAF Arnot Gobas), L/kg ww	Screening B conclusion
#1 (Parent substance UVCB) / Constituant No.1	CCCCCCC(O)CCCCCCCCCCC(=O)NCCCCCCNC(=O)CCCCCCCCCCC(O)CCCCCC	681	13.28	-	11.19	0.8934	Predicted Not B/vB
#1 (Parent substance UVCB) / Constituant No.2	C(CCCCCNC(CCCCCCCCCCC(CCCCCC)O)=O)NC(CCCCCCCCCCCCCCCCC)=O	665	14,4	-	3,1	-	Predicted Not B/vB
#1 (Parent substance UVCB) / Constituant No.3	N(C(CCCCCCCCCCC(CCCCCC)O)=O)CCCCCCNC(CCCCCCCCCCC(CCCCCC)OC(=O)CCCCCCCCCCC(CCCCCC)O)=O	963	20.6	-	3.1	-	Predicted Not B/vB