Calcium(2+) 12-hydroxyoctadecanoate

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 on 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 substances.

The water solubilities of the calcium salts of monocarboxylic acids C14-C22 are all similar, in the range of 0.15 to 3.07 mg/L at 20°C. The data are taken from proprietary studies on calcium myristate, calcium 12-hydroxystearate and calcium behenate (Harlan 2013) as well as calcium stearate (TUV Bayern 1992).

The partition coefficient could not be determined because the solubility in n-octanol was insufficient. The adsorption coefficient for calcium 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 not available.

The vapour pressure of the calcium 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 calcium salts of monocarboxylic acids C14 to C22 category are below 10 E-10 Pa.

Due to their low solubility in water and octanol, partition coefficients could not be determined for these substances. As the 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 R7c (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 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 on 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 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. Calcium salts of monocarboxylic acids are readily biodegradable and therefore are not expected to be present in any sewage sludge applied in agriculture. The vapour pressures of the calcium 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 (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 thickeners are readily biodegradable, are generally formed in-situ in the grease base, have low volatility (so aerial deposition is unlikely), and are not applied directly to soil. Thus, terrestrial exposure of calcium 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 (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

Harlan Laboratories (2013). Calcium myristate: Determination of general physico-chemical properties. Testing laboratory: Harlan Laboratories Ltd., Shardlow Business Park, Shardlow, Derbyshire, DE72 2GD, UK. Owner company: European REACH Grease Thickeners Consortium Escrow Foundation, Hemonylaan 26, 1074 BJ Amsterdam, The Netherlands. Report date: 2013 -04 -11.

Harlan Laboratories (2013). Calcium 12-hydroxystearate: Determination of general physico-chemical properties. Testing laboratory: Harlan Laboratories Ltd., Shardlow Business Park, Shardlow, Derbyshire, DE72 2GD, UK. Owner company: European REACH Grease Thickeners Consortium Escrow Foundation, Hemonylaan 26, 1074 BJ Amsterdam, The Netherlands. Report date: 2013 -04 -11.

Harlan Laboratories (2013). Calcium behenate: Determination of general physico-chemical properties. Testing laboratory: Harlan Laboratories Ltd., Shardlow Business Park, Shardlow, Derbyshire, DE72 2GD, UK. Owner company: European REACH Grease Thickeners Consortium Escrow Foundation, Hemonylaan 26, 1074 BJ Amsterdam, The Netherlands. Report date: 2013 -04 -11.

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

TUV Bayern (1992). Investigation report: Implementation of ecotoxicological tests of products. Testing laboratory: TUV Bayern, Westendstrasse 199, Postfach 210420, D-8000 Munchen 21. Report no.: G3-UTA 10-Dr. re. Owner company: European REACH Grease Thickeners Consortium member company. Study number: A. -Nr. 114 2011. Report date: 1992-09-22.