Fatty acids, C16-18, calcium salts

Endpoint summary

Description of key information

It is considered from the results that all the substances in the category of calcium salts of C14-C22 monocarboxylic acids exhibit a similar lack of acute oral and dermal toxicity potential across the entire category. There is no evidence of a relevant intrinsic acute oral or dermal toxicity requiring classification or substance specific RMMs.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

High

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

High

Additional information

The substances in the category are considered to be similar on the basis that they have common structures of a calcium ion varying only by the length of the fatty acid chain and the presence of unsaturated and/or hydroxyl functional groups. As a result it is expected that the substances will have similar, predictable properties. REACH Annex V, Entry 9, groups fatty acids and their potassium, sodium, calcium and magnesium salts, including C6 to C24, predominantly even-numbered, unbranched, saturated or unsaturated aliphatic monocarboxylic acids. Provided that they are obtained from natural sources and are not chemically modified, the substances included in REACH Annex V, Entry 9 are exempt from registration, unless they are classified as dangerous (except for flammability, skin irritation or eye irritation) or they meet the criteria for PBT/vPvB substances. The metal fatty acid substances in the category are therefore not expected to be hazardous. Due to the close structural similarity and the narrow range of carbon chain numbers covered in this category, the acute toxicity properties are expected to be predictable across the category.

Since REACH Annex V groups together calcium, potassium, sodium and magnesium salts of C6 to C24 fatty acids as being potentially exempt from registration, these metal cations are therefore not considered to contribute to any health hazard. On this basis, relevant published or proprietary data on any potassium, sodium or magnesium salt within the fatty acid category range of C14 to C22 can be used to read across to the calcium salts of C14-C22 fatty acid category.

Lithium salts of fatty acids are not included in REACH Annex V as being potentially exempt from registration. For these salts it is expected that the lithium cation would be the species with the potentially higher toxicity profile when compared to calcium, potassium, sodium, and magnesium cations. However, the substance fatty acids C18 (unsaturated) lithium salts contains a fatty acid anion that falls within the C14-C22 range. Experimental data for all the mammalian toxicity Annex VIII endpoints have been generated on this substance and the results obtained are relevant to read across to the calcium salts of C14-C22 fatty acids either in a weight of evidence approach or as key studies due to the structural similarity and its position within the category fatty acid range. This is clearly relevant when the results from the lithium fatty acid salts are negative.

HERA (2002) reviews published data on fatty acid and fatty acid salt acute toxicity. The HERA review also considers data presented in CIR (1982) and IUCLID (2000). All the data on simple metal salts of fatty acids show evidence of low acute oral and dermal toxicity, e.g. >5000 mg/kg bw for sodium stearate and >2000 mg/kg bw for fatty acids, C16-18 and C18-unsaturated, sodium salts. Since the salts of fatty acids will exhibit a similar toxicity profile as the comparable free acids, the available data for relevant fatty acids within the C14-C22 range provide a clear picture of low acute toxicity for this class of substance, with all oral LD₅₀values >2000 mg/kg bw for palmitic, stearic, oleic, fatty acids C18-22, etc.

The category substances are exclusivelymanufactured in situ in base oil and not in isolated form. They have vapour pressures of less than 10 E-10 Pa and melting points of greater than 120°C, so the potential for the generation of inhalable forms is low, also the use of the grease forms will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be unlikely to occur.In accordance with REACH Regulation, Annex VIII, 8.6.1, column 2 as well as Annex XI, 1, the performance of acute inhalation toxicity studies is not justified due to exposure as well as toxicological considerations.

In order to provide an additional weight of evidence conclusion concerning acute toxicity, a number of key acute oral and dermal toxicity studies in rats have been conducted on lithium salts of C14, C18 (hydroxylated), C18, and C22 monocarboxylic acids. The results from these studies showed no evidence of acute toxicity up to the highest doses tested (2000 mg/kg bw or greater).

While this information was obtained from an assessment of lithium fatty acid salts within the carbon range C14-C22, it is considered relevant to read the results across to the calcium fatty salts in this category since lithium is a simple metal in group one of the periodic table, along with sodium and potassium (see also the introduction to this section). Additionally, whereas the lithium cation might be expected to demonstrate higher acute hazard potential than the calcium, magnesium, potassium and sodium cations, the lack of acute toxicity from the studies on lithium fatty acid salts up to the maximum concentrations tested is directly applicable to the C14-C22 calcium (or magnesium, potassium, sodium) fatty acid salts.

Therefore, it is considered that the substances in the category of calcium fatty acid salts exhibit a lack of acute oral and dermal toxicity potential across the entire category.

Reference

HERA (Human Health and Environmental Risk Assessment on ingredients of European household cleaning products) (2002) Fatty Acid Salts (Soap) Environmental and Human Health Risk Assessment

IUCLID (2000) IUCLID Datasets for fatty acids. Created February 2000. European Chemical Bureau, Ispra, Italy.

Justification for selection of acute toxicity – oral endpoint
This substance is a representative fatty acid salt that can be read across to the calcium salts of C14-C22 fatty acids category

Justification for selection of acute toxicity – dermal endpoint
This substance is a representative fatty acid salt that can be read across to the calcium salts of C14-C22 fatty acids category

Justification for classification or non-classification

The oral and dermal LD50 values are greater than 2000 mg/kg bw.