1,2-dimethylimidazole

Endpoint summary

Additional information

A GLP study performed according to OECD Guideline 208 (2006) is available for the test substance. Six plant species from five different plant families were tested: Brassica napus, Glycine max, Cucumis sativus, Solanum lycopersicum, Lolium perenne and Zea mays. The most sensitive species in terms of fresh weight was Brassica napus with an EC10 value of 24.32 mg/kg soil dry weight. This species was followed by Cucumis sativus and Glycine max with EC50 values of 125.95 and 66.10 mg/kg soil dry weight, respectively). The least sensitive species was Zea mays with NOEC value of 320 mg /kg soil dry weight. No ECx values could be calculated for Zea mays and due to the lacking concentration/response Solanum lycopersicum. The determined NOEC value for Solanum lycopersicum is 80 mg/kg soil dry weight.

Therefore, no other data doesn’t need to be conducted since an appropriate long-term study on terrestrial plants is available.

Additionally, a GLP study conducted according to OECD guideline 216 was performed with the test substance. As there were no meaningful concentration response curves obtained for day 0, day 7, day 15 and day 28 values (p(F) > 0.05; i.e., slope of the relationship is not significantly different from zero), ECx values derived from the statistical analysis are not valid are therefore, not scientifically reliable. The EC50 value is likely to be higher than the highest test concentration assessed.

No studies on the long-term reproductive toxicity to birds are available for the substance.

In Annex X, Section 9.6.1, Column 2 of Regulation (EC) No 1907/2006, it is laid down that any need for testing should be carefully considered taking into account the large mammalian dataset that is usually available at this tonnage level. In case of the substance a mammalian dataset is available. Furthermore, ECHA (2017) states in the "Guidance on information requirements and chemical safety assessment Chapter R.7c" (R.7.10.16) that "given that mammalian toxicity is considered in detail for human health protection, the need for additional data for birds must be considered very carefully – new tests are a last resort in the data collection process."

In case of 1,2-dimethylimidazole (CAS 1739-84-0) a mammalian dataset is available.

In addition, based on the low log Kow, significant bioaccumulation in organisms is not to be expected (see IUCLID Ch. 5.3.1). The Substance is also biodegradable based on an enhanced ready biodegradability test passing the degradation level of 60% CO2/ThCO2 but not meeting the 10-day window (BASF SE, 2012; see IUCLID Ch 5.2.1); therefore, the substance is assessed to be not P/vP. Hence, secondary poisoning is of no concern.

Therefore, and for reasons of animal welfare, long-term or reproductive toxicity tests on birds do not need to be conducted.

Following Table R.7.11-2 of REACH Guidance Document R.7c (ECHA, 2017), the substance belongs to soil hazard category 3. Therefore, the risk to the soil compartment will be assessed based on the comparison of the PNEC derived using the equilibrium partitioning method (EPM) and the results of a long-term soil toxicity test with the most sensitive organism group as indicated from aquatic toxicity data.