Aluminum, benzoate C16-18-fatty acids complexes

Endpoint summary

Additional information

No data are available for the toxicity to terrestrial organisms. Aluminum, benzoate C16-18-fatty acids complexes exhibits no measurable aquatic toxicity or bioavailability and direct and indirect emissions are unlikely. Therefore no testing has been proposed for toxicity to terrestrial organisms and the endpoints have been waived on the basis that there is expected to be no exposure of the terrestrial environment.

Equilibrium partitioning

The ECHA guidance document Chapter R.10 – Dose [Concentration]-Response Regarding Environment guidance document (ECHA 2008) states that “when no toxicity data are available for soil organisms, the equilibrium partitioning method is applied to identify a potential risk to soil organisms”. Equilibrium partitioning is based on estimation of the toxicity to terrestrial organisms from the aquatic toxicity and the physico-chemical and environmental fate properties of the substance.

The water solubility of aluminum, benzoate C16-18-fatty acids complexes was measured as <0.00026 g/L (Harlan 2013) at 20ºC and the vapour pressure was determined to be 0.000044 Pa at 25ºC (Harlan 2013), therefore it is possible to make an estimation of Henry’s Law Constant. However, no determination of the partition coefficient was possible by the shake-flask method as detailed in Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 107 of the OECD Guidelines for Testing of Chemicals, 27 July 1995. This was due to the insolubility of aluminum, benzoate C16-18-fatty acids complexes in both n-octanol and water. Further to this, determination of the partition coefficient by the HPLC estimation method as detailed in Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Method 117 of the OECD Guidelines for Testing of Chemicals, 13 April 2004, was also not possible. This was due to the insolubility of aluminum, benzoate C16-18-fatty acids complexes in suitable reverse phase HPLC solvents.

As the partition coefficient and adsorption/desorption coefficient could not be determined, it is not possible to use the equilibrium partitioning method to estimate the toxicity to terrestrial organisms.

Exposure

These endpoints may be waived if it can be demonstrated that direct and indirect exposure of soil is unlikely to occur. ECHA (2012) states that “In the case of readily biodegradable substances which are not directly applied to soil, it is generally assumed that the substances will not enter the terrestrial environment and as such there is no need for testing of soil organisms”. Therefore, as the substance is readily biodegradable and is not applied directly to soil testing of terrestrial ecotoxicity endpoints is not required.

ECHA guidance document REACH Chapter R.10 – Dose [Concentration]-Response Regarding Environment (2008) states that chemicals can reach the soil via several routes: application of sewage sludge in agriculture, direct application of chemicals and deposition from the atmosphere. The substance is used as a thickener in lubricants and greases in open and closed systems and thus there is no direct application to soil. The fatty acid and benzoic acid components of the substance are readily biodegradable. At environmental pH (ca 7.0) aluminium will mainly be in the form of essentially insoluble hydrated oxide species which are likely to absorb onto sewage sludge. However, hydrated aluminium oxides occur naturally in the environment and are not considered hazardous. The vapour pressure of aluminum, benzoate C16-18-fatty acids complexes was determined to be 0.000044 Pa at 25 ºC (Harlan 2013). As the substance has very low volatility it is not expected to enter the atmosphere. Thus aerial deposition of the substance will be negligible and deposition is not expected to be a relevant route of exposure. As the substance is readily biodegradable, has low volatility and is not applied directly to soil, it is generally assumed that it will not enter the terrestrial environment.

In most cases the reactions to form the grease thickener occur in situ during the grease manufacturing process and consequently these grease thickeners normally only exist in the base oil matrix. The matrix effect, as recognised by the OECD Lubricant Emission Scenario document (OECD 2004), needs to be taken into account as the process of manufacturing the thickener in an inert base oil is likely to influence factors such as availability of the thickeners. In the grease manufacturing process unique interactions, more appropriately defined as physical bonding effects, occur between the base oils and the thickeners. The chemistry is complex and 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. In realistic use scenarios, the thickeners will be contained in base oil, with the formulated greases specifically designed to minimise the leaching of the thickener. Therefore during use, the concentrations of the substances which would be bioavailable are limited.

The isolated thickener is unlikely to come in contact with the terrestrial environment. Thus the derivation of terrestrial toxicity data on the isolated thickener is not considered to be relevant to the potential exposure of the substance in the environment.

Conclusion for terrestrial toxicity

The fatty acid and benzoic acid components of the thickener are readily biodegradable, and the aluminium component, while it is expected to partition to sewage sludge or soil in the form of hydrated aluminium oxides, is not expected to be hazardous. Since the thickener has low volatility, aerial deposition is unlikely, and the substance is not applied directly to soil. Thus, terrestrial exposure of aluminum, benzoate C16-18-fatty acids complexes is considered to be unlikely and as the terrestrial toxicity would not be environmentally relevant, these tests have not been conducted.

References

ECHA (2012) Guidance on information requirements and chemical safety assessment – Chapter R.7c: Endpoint Specific Guidance. European Chemicals Agency

 

ECHA (2008) Guidance on information requirements and chemical safety assessment – Chapter R.10: Dose [Concentration]-Response Regarding Environment. European Chemicals Agency

 

OECD (2004) OECD Series on emission scenario documents, Number 10: Emission scenario document on lubricants and lubricant additives. Environment directorate: Joint meeting of the chemicals committee and the working part on chemicals, pesticides and biotechnology. ENV/JM/MONO(2004)21