C18 (branched) fatty acids, esters with mono-, di-, and tri-glycerol

Endpoint summary

Additional information

The registration substance is used as a cosmetic emoliant and water oil emulsifier. This function is related to its unpolar isostearate moieies and free hydroxyl groups.In contrast to alkanoate triglycerid oils with an extreme low water solubility, the registration substance has a low but measureable water solubility of 3 mg/L at 20 deg C (see IUCLID Chapter 4.8). Above the water solubility a dispersion of the registration substance is formed and testing water filtrating daphnia are then at risk to get harmed based on physico-chemical effects by this emulsion droplets rather than toxic interactions e.g. via membranes.The registration substance is a complex mixture and a specific analysis e.g. with LC MS MS could not be performed reliably. Instead the TOC of the test media were measured.

The aqueous test media were prepared by dispersing the registration substance at different loadings by stirring for 72h at 1100 rpm. After separation of the phases for 1h, the WAF were taken from the homogenous liquid phase from the center of the glass flask. In the table below the nominal loading rates in mg/L were compared with the measured TOC in mg/L of the daphnia test media at the test beginn and test end.

 

Table Loading rate and TOC of the Daphnia test media (Details s. IUCLID Chapter 6.1.3 Daphnia test)

 

 

Loading rate WAF (mg/L)	TOC at test start(mg/L)	TOC at test end(mg/L)
100	8.1	8.2
50	3.3	3.2
25	3.2	3.1
12.5	2.6	2.8
6.25	< 2	2.4
Control	< 2	< 2

 

There seems to be no correlation between loading rate and measured TOC. Using Diglyceryl diisostearate as model substance in the complex mixture with a composition of C42H82O7 & Molweight of 699.12 g/Mol the TOC is 72,2% and a water solubility of 3 mg/L would correspond to 2.2 mg/L TOC. The loading rate of 12.5 mg/L corresponding to 2.6 -2.8 mg/L TOC may be regarded as already above the water solubility.

In the WAF tests with Fish (see IUCLID Chapter 6.1.1) and Algae (see IUCLID Chapter 6.1.5) no toxicity was observed after 96h respectively 72h even at a loading rate of 100 mg/L respectively 250 mg/L.

The WAF test with Daphnia (see IUCLID Chapter 6.1.3) no immobilization was observed after 48h up to a loading rate of 12.5 mg/L which may be regarded already above water solubility. At loading loading rates 25, 50 and 100 mg/L immobilization was observed but it is very likely that this a secondary effect caused by the oil droplets of the emulsion interfering with the ability to filtrate water by the daphnia.

In an OECD 209 study no effects on the respiration rate of municipal activated sludge were observed at the highest tested concentration of 1000 mg/L which means no hazard identfied.

The observed low ecotoxity is supported by a caluclated Log Kow of >14 for the model substance Diglyceryl diisostearate which means that uptake into organisms and hence bioaccumulation are very low.

 

The chronic toxicity was asssessed by using data from OECD SIDS and HERA Risk assessment reports in combination of accepted calculation methods. The values found are either above the water solubility or unlikely to come into effect. Therefore no hazard is identified for chronic endpoints.

 

CONCLUSION

Fish, Daphnia and Algae were tested with Diglyceryl diisostearate in WAF (Water Accomodated Fraction) media using different loading rates. Up to the water solubility of the registration substance of 3 mg/L at 20 deg C no ecotoxicty was observed for fish, daphnia and algae which is in line with the high Log Kow resulting in very low uptake into organisms, very low bioaccumulation and ecotoxicity. Based on this findings no PNECs were derived. For fish, daphnia, algae and microorganisms no hazards were identified in the forementioned tests.