Quaternary ammonium compounds, di-C8-10-alkyldimethyl, chlorides

Endpoint summary

Description of key information

A reliable OECD 301B test guideline study (Klimisch 1) to determine the ready biodegradability for the read across substance, N,N-Didecyl-N,N-dimethylammonium carbonate (DDACarbonate) (NOACK, 2007), measured 10 % biodegradation (beginning of biodegradation) after 5 days and the pass level of 60 % after 12 days. The 2nd test item replicate reached the 10 % level after 4 days and the pass level of 60 % after 10 days. At test end a biodegradation rate of 99 % was reached. The positive control and toxicity controls both passed the test criteria, demonstrating the test system was functioning well and the test substance was not toxic to the microorganisms. The results indicate the test substance is readily biodegradable.

Another reliable OECD 301B test guideline study (Klimisch 1) to determine the ready biodegradability for the read across substance, N,N-Didecyl-N,N-dimethylammonium carbonate (DDACarbonate) (NOACK, 2008). Again, the positive control and toxicity controls both passed the test criteria, with percentage degradation of the positive control reaching the pass level of 60 % after 6 days, with 81 % after 14 days. In the toxicity control containing both test and reference item a biodegradation rate of 62 % occurred within 14 days and came to 97 % after 28 days. In the test vessels, the 10 % level (beginning of biodegradation) was reached after 11 days and the pass level of 60 % after 19 days. The mean biodegradation came to 96 % after 28 days.

In addition, four reliable studies are available for the read across substance (DDAC). A reliable study by Clariant (1992) included two separate experiments, one conducted according to OECD 301A (Die away test) and the other conducted according to OECD 302B guidelines (inherent biodegradability, Zahn Wellens). Activated sludge from a sewage treatment plant was used for the OECD 302B test, which after 28 days, was used as pre-adapted sludge for the Die-away study. In the Zahn-Wellens Test elimination of DDAC after 28 days was 95.5 % (related to 3 h-value). In the DOC Die-Away Test the maximum degradation was 90 % and fulfilled the 10-day window criteria. A further reliable study was carried out by Wildlife (1996) according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) using DDAC. The results of this study indicated that both un-complexed and test substance complexed to bentonite clay were biodegradable when exposed to unacclimated microorganisms obtained from a receiving system representative of a site where these test substances may be expected to be discharged. Degradation of 77.5 % was attained for non-complexed test substance after 28 days, and slightly lower when DDAC was complexed with clay. A further Wildlife study (2001) conducted not according to guidelines, in which activated sludge pre-exposed to non-labelled DDAC, was exposed to radiolabelled DDAC for a 28 days period and the DDAC (plus metabolites) in the different phases (sludge, water and mineralisation) were measured. 14CO2 production reached 71.82 % at Day 1, 88.36 % at Day 7, and 93.30 % at Day 28, with low amounts of DDAC or metabolites measured in the sludge or water phases. The fourth study on DDAC by ABC Laboratories (1993) was conducted according to the EPA OPTS 796.3100 guideline, using a mix of inoculum from soil, activated sludge and influent sewage. Degradation of 80.92% was attained after 28 days.

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