Imidazolium compounds, 2-C17-unsatd.-alkyl-1-(2-C18-unsatd. amidoethyl)-4,5-dihydro-N-methyl, Me sulfates

Endpoint summary

Additional information

No test results for bioaccumulation with oleic-acid based IQAC, DMS quaternised itself are at hand. Considering the rapid hydrolysis at pH 7 (2.9 days) and pH 9 (1.2 days) as well as the inherent biodegradability, demonstrating the ability of organisms to metabolize the substance, a relevant bioaccumulation potential of oleic-acid based IQAC, DMS quaternised is not expected.

This is also supported by the outcome of three toxicokinetical studies with mammals (rats) made with radiolabelled IQAC, DMS quaternised (3 tests, 1.: Oleic acid based IQAC, 2.: tallow acid based IQAC and 3.: hydrogenated tallow acid based IQAC). The toxicokinetical studies resulted in poor absorption (dermal and intestinally) and fast elimination of the small amount of substance being absorbed (see 5.1.3. Summary and discussion of toxicokinetics).

The expectation of no relevant bioaccumulation of the substance is also supported by a modeling approach performed by Meylan et al. (1999). To develop a model on bioaccumulation, Meylan et al. (1999) collected measured BCF (sources: AQUIRE, CITI, HSDB and EFDB), log Kow (sources: MEDCHEM 'star list', Sangster's LOGKOW DATABANK or sources referenced in the EFDB or KOWWIN estimates), and pKa values for ionizing substances (sources: SRC's PHYSPROP database, compilation of Perrin and Serjeant and Dempsey and reference handbooks such as Handbook of Organic Chemistry, the Handbook of Chemistry and Physics and other sources cited in the EFDB or calculated using pKalc 3.1 software or SPARC). The database of 694 compounds with recommended BCF values contained 84 compounds defined as ionic, including carboxylic acids, sulfonic acids, and quaternary ammonium compounds. Based on the correlation of measured log BCF values and log Kow, log BCF values were deduced. The results were used to develop the computer program BCFWIN. BCFBAF, an update of the original BCFWIN program, was used to calculate the BCF values for the oleic-acid based IQAC, DMS quaternised. For the update, a more recent and better evaluated database of BCF values was used for both training and validation. The BCF data were re-regressed using the same methodology as in the original BCFWIN program. (The original estimation methodology used by the original BCFWIN program is described in a document prepared for the U.S. Environmental Protection Agency (Meylan et al., 1997). The estimation methodology was then published in journal article (Meylan et al, 1999).)   
The calculation yielded values in the range between 1 (Arnot-Gobas calculation method (upper trophic)) and 71 L/kg wet-wt (regression-based calculation method). Based on the calculated BCFs a low potential for bioaccumulation is to be expected for oleic-acid based IQAC, DMS quaternised. Measured BCFs for oleic-acid based IQAC, DMS quaternised are not available.

 

A measured BCF of 10.7 is the result of an open domain study with a closely related structural homologue (partially unsaturated IQAC, DMS quaternised, CAS-No. 68122-86-1), cited by NICNAS (1999). This homologue has been tested in a study with bluegill sunfish in a flow through system. The study is indicating a low bioaccumulation potential (BCF = 10.7) of IQAC.