Castor oil, hydrogenated, lithium salt

Endpoint summary

Additional information

No data are available for the toxicity to terrestrial organisms. Category members exhibit no measureable 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 2008b) 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 substances.

Most of the substances in this category, those with a carbon chain length of below C22, have surface active properties. Due to the surfactant nature, these substances are not truly soluble in water but form stable dispersions instead. As these stable dispersions could not be removed, it was not possible to determine a water solubility value for lithium salts of monocarboxylic acids C14 to <C22 (Harlan 2012). Lithium behenate (C22) was determined to be not surface active, however an unbounded water solubility value could not be determined; the water solubility of lithium behenate was measured as <0.000046 g/L (Harlan 2013).

Due to the surface active nature of the substances, the partition coefficient also could not be determined for lithium salts of monocarboxylic acids C14 up to C22. For lithium behenate (C22), which does not have surface active properties, the partition coefficient could not be determined because the solubility in n-octanol was insufficient (Harlan 2013). The adsorption coefficient for lithium salts of monocarboxylic acids C14 to C22 could not be determined because the HPLC screening method is not valid for organic acids and could not be calculated as a partition coefficient was unavailable.

The vapour pressure of the lithium salts of monocarboxylic acids C14 to C22 could not be determined because the test is technically not feasible. Standard test methods, according to OECD guideline 104, are able to measure vapour pressure from 10 E-10 Pa to 10 E+05 Pa, but the predicted vapour pressures for the substances in the lithium salts of monocarboxylic acids C14 to C22 category are below 10 E-10 Pa (US EPA 2009).

Due to their surface active properties, partition coefficients could not be determined for these substances. As the water solubility, partition coefficient, adsorption/desorption coefficient and the vapour pressure 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 (2012e) 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 substances in this category are readily biodegradable and are 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 (2008b) 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 substances in this category are used as thickeners in lubricants and greases in open and closed systems and thus there is no direct application to soil. The fatty acid component of lithium salts of monocarboxylic acids are readily biodegradable. In addition, the lithium ion is not expected to partition to sludge or soil, but instead to remain in solution. Therefore these compounds are not expected to be present in any sewage sludge applied in agriculture. The vapour pressure of the lithium fatty acid salts in the category are estimated to be below 10 E-10 Pa and as the substances have very low volatility, they are not expected to enter the atmosphere. Thus aerial deposition of the substances will be negligible and deposition is not expected to be a relevant route of exposure. As the substances are readily biodegradable, have low volatility and are not applied directly to soil, it is generally assumed that they 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 thickeners is not considered to be relevant to the potential exposure of these substances in the environment.

Conclusion for terrestrial toxicity

The fatty acid component of these thickeners are readily biodegradable, and the lithium ion is not expected to partition to sewage sludge or soil, they have low volatility (so aerial deposition is unlikely), and are not applied directly to soil. Thus, terrestrial exposure of lithium salts of monocarboxylic acids C14-C22 is considered to be unlikely and as the terrestrial toxicity would not be environmentally relevant, these tests have not been conducted.

References

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

 

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

Harlan Laboratories (2012k). Lithium myristate: Determination of general physico-chemical properties. Testing laboratory: Harlan Laboratories Ltd., Shardlow Business Park, Shardlow, Derbyshire, DE72 2GD, UK. Report number: 41104042. Owner company: European REACH Grease Thickeners Consortium Escrow Foundation, Hemonylaan 26, 1074 BJ Amsterdam, The Netherlands.

Harlan Laboratories (2012l). Lithium 12-hydroxystearate: Determination of general physico-chemical properties. Testing laboratory: Harlan Laboratories Ltd., Shardlow Business Park, Shardlow, Derbyshire, DE72 2GD, UK. Report number: 41104045. Owner company: European REACH Grease Thickeners Consortium Escrow Foundation, Hemonylaan 26, 1074 BJ Amsterdam, The Netherlands.

Harlan Laboratories (2013d). Lithium behenate: Determination of general physico-chemical properties. Testing laboratory: Harlan Laboratories Ltd., Shardlow Business Park, Shardlow, Derbyshire, DE72 2GD, UK. Report number: 41104047. Owner company: European REACH Grease Thickeners Consortium Escrow Foundation, Hemonylaan 26, 1074 BJ Amsterdam, The Netherlands.

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

US EPA (United States Environmental Protection Agency) (2009). MPBPVP v1.43. Estimation Programs Interface (EPI) Suite, v4.00 developed by the US Environmental Protection Agency's Office of Pollution Prevention and Toxics and Syracuse Research Corporation (SRC)