Registration Dossier

Administrative data

toxicity to soil microorganisms
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because direct and indirect exposure of the soil compartment is unlikely
Justification for type of information:
As set out in the endpoint summary, terrestrial toxicity studies are not considered to be scientifically relevant for the substances in the lithium salts of monocarboxylic acids C14-C22 category.
Lithium salts of monocarboxylic acids C14-C22 are readily biodegradable, have low potential for bioaccumulation, and show no acute or chronic aquatic toxicity at the limit of solubility. No data are available on the partition coefficient or potential for adsorption/desorption of these substances.
The substances in this category are used as thickeners in greases; the identified uses do not involve direct application to soil. The uses are not expected to lead to significant quantities entering the sewage system and the substances are readily biodegradable so the compounds are not expected to be present in sewage sludge applied in agriculture (see sections 9 and 10 of the CSR). The substances have very low vapour pressures, so would not be expected to enter the atmosphere and aerial deposition would not be relevant for soil exposure.
The substances are expected to dissociate in the aquatic environment into lithium cations and fatty acid anions. The dissociation and biodegradation in the environment would result in carbon dioxide, water and lithium ions, with no stable degradation products. The fatty acids are exempt from REACH under Annex V and, therefore, by extrapolation, represent a known and controllable hazard. Lithium ions in the aqueous environment would remain in solution and, as lithium is a naturally occurring element, “found in small amounts in nearly all igneous rocks and in the waters of many mineral springs” (Lide 2009), the adsorption/desorption of lithium in the environment is not expected to be scientifically relevant.
The identified uses of the substances relate to their use as thickeners in formulated greases, for which the substances are typically manufactured in situ in base oil so exposure to the isolated thickeners would not occur. Furthermore, the majority of greased parts are designed to keep the grease within the contact zone, even in the event of catastrophic failure, and most grease-lubricated parts are sealed for life, so the potential for exposure to the even the formulated grease is limited.
The formulated greases are designed to minimise the leaching of the thickener from the base oil to water, and the very low solubility of the substances in water, the concentrations of the substances which would be available for adsorption to soil or sediment are limited. This is supported by the leaching studies undertaken on lithium 12-hydroxystearate grease (see leaching summary in IUCLID and CSR), which showed lithium concentrations of <0.1 mg/L in the WAF and SPME readings equivalent to background concentrations. Lithium soap-based grease thickeners are concluded as not bioaccessible and the measured concentration of lithium in the WAF of the leaching studies was below the ecotoxicological effect values.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion