Oxoaluminium, C16-C18-alkyl esters

Endpoint summary

Description of key information

There is no evidence from the experimental studies to indicate that the substance is absorbed systemically. No information on distribution, metabolism or excretion can be derived from the experimental data.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

Experimental data for the mammalian toxicity Annex VII and VIII endpoints have been generated on this and a related substance.

The following conclusions can be drawn on the basis of a review of available key experimental data from physico-chemical and toxicological studies on the registered substance performed according to international technical guidelines and in compliance with GLP in internationally recognised contract research organisations and read across from aluminum, benzoate C16 -18 fatty acid complexes:

· The substance does not appear to be absorbed via the gastrointestinal tract. This is supported by the lack of systemic toxicity at single doses of up to 2000 mg/kg b.w., as a suspension in poly alpha olefin via oral gavage in an acute oral toxicity study in male and female Wistar rats. Also, read-across data from a supporting repeated daily oral gavage dosing at lower concentrations to male and female rats for at least 42 days with aluminum, benzoate C16-18 fatty acid complexes would corroborate this conclusion. Alternatively, though the lack of toxicity via the oral route may also be indicative of high threshold toxicity for the substance over the relatively short-term exposures examined.

A lack of any systemic toxicity was observed in the acute oral toxicity study, which was conducted on the substance as a suspension in poly alpha olefin, at doses up to 2000 mg/kg bw.

An OECD 422 study was conducted in rats by daily oral gavage administration of aluminium, benzoate, C16-18 fatty acids complexes manufactured in situ in a medicinal grade white oil base and the results have been read across to the registered substance . There were no effects on any of the reproductive or developmental parameters measured. As the maximum dose that could be administered was limited by the physico-chemical characteristics of the dosing preparation, the limit dose of actual aluminium, benzoate C16-18 fatty acid complexes could not be attained and the maximum dose was below the limit dose of 1500 mg/kg/day (actual maximum dose achieved was 225 mg/kg bw/day, which was considered to be the NOAEL).

The registered substance is manufactured and used solely in situ in an inert carrier. The registered substance and aluminium, benzoate, C16 -18 fatty acids complexes are used specifically as thickeners in industrial greases and lubricants and, as such, typically occur in base oil. The interactions between the thickener and base oil do not strictly fall under the definitions of a reaction product nor do they act as a simple mixture of components due to the matrix effects which occur in the manufacturing/ blending process. Matrix effects should be taken into account when assessing whether adverse effects would be seen in grease products because entrainment of grease thickeners during the manufacturing process as part of the grease matrix severely limits exposure and will have a significant impact on the outcome of any risk assessments. The fact that matrix effects do occur is a point recognised in the OECD Lubricant Emission Scenario document (2004) and it is therefore reasonable to assess the influence the process of manufacturing the thickener in an inert base oil has on factors such as availability, which are critical to assessing the potential risks posed by the grease thickeners when in the grease.

Leaching tests have been undertaken to assess whether the metallic components of the metal-soap and metal-complex-soap grease thickeners remain in base grease(s) and hence determine the degree of availability of the thickeners (see section 4.5 and Appendix 2 of the CSR). The results of the study show no leaching of the thickener from the base oil and a lack of bioavailability of the substance in aqueous media. The same lack of bioavailability is expected in GI fluids as well and, as a further demonstration of this lack of availability, it is proposed to conduct leaching studies on aluminium thickeners in base oil using fed state simulated intestinal fluid (FeSSIF).

This substance has been registered by a Member of the European REACH Grease Thickeners Consortium (ERGTC). A number of decisions have been made in the dossier with regard to the approach taken for registering the substance including the testing strategy and the justification for waiving certain endpoints. Several of the decisions reflect the technical difficulties of testing the substance and the relevance of data with regard to the potential for exposure, given that the substance typically occurs in situ in base oil. A face to face meeting between the ERGTC and ECHA was held in Helsinki on 8th September 2016 which discussed many of these topics and a copy of the minutes from the meeting are attached to the dossier (See section 13 of IUCLID). Therefore, if there are any queries or concerns which arise when the dossier is reviewed, it is requested that the reviewer discuss these with the ERGTC ([e-mail]) as there may be background information and previous discussions between the ERGTC and ECHA which are relevant.

· There are no experimental data for the registered substance to show lack of absorption via the skin. However, read-across data from a supporting acute dermal toxicity study with aluminum, benzoate C16-18 fatty acid complexes at doses up to 2000 mg/kg b.w. in male and female Wistar rats showed a lack of any systemic toxicity via the dermal route. Also there was an absence of any change in stimulation index following topical application of aluminum, benzoate C16 -18 fatty acid complexes in a propylene glycol suspension in a local lymph node assay. Although lack of dermal absorption is the likely scenario for the absence of systemic effects via this route of exposure, the alternative explanation of high threshold toxicity over the short-term exposure examined cannot be ruled out.

No available data from these studies allows conclusions to be drawn regarding distribution, metabolism or excretion of the registered substance.