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Environmental fate & pathways

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The biodegradation of 2,2',2''-nitrilotriethanol (TEA), the major constituent, was best examined by West & Gonsior (1996). Tests were conducted with 14C-labelled TEA regarding the biodegradation in soil, river water and river water-sediment systems as well as the activated sludge reaction. In a water-sediment microcosm-study with natural sediment and water samples a maximum biodegradation half-life of 0.6 days and a maximum mineralization half-life of 7.2 days was found.

In a river-water microcosm-study with natural river water samples a maximum biodegradation half-life of 1.7 days and a maximum mineralization half-life of 1.9 days was found.

Depending on the initial test substance concentration under semi-realistic conditions with soil microcosms using natural sandy loam soil a maximum biodegradation half-life of 1.8 days and a maximum mineralization half-life of 5.4 days were determined.

In a test with activated sludge biodegradation half-lifes between 0.01 and 0.51 days and mineralization half-lifes between 0.24 and 0.67 days were found, depending on the initial concentration of the test substance (164 and 818 mg/L) and the concentration of the activated sludge (0.6 and 5.7 mg/L MLSS).

These results indicate, that2,2’,2’’-nitrilotriethanol is readily biodegradable. A ready test performed by Gerike (1978) according to a precursor of the Modified OECD Screeening Test (OECD TG 301 E) using non-adapted effluent from a waste water treatment plant as inoculum supports these results.

In the Guidance on the application of CLP criteria, a substance can be identified as rapidly biodegradable if the measured rate constant in the different environmental compartments is > 0.043 d-1 (Guidance on the application of CLP criteria, Guidance to regulation (EC) No 1272/2008 on classification, labelling and packaging (CLP) of substances and mixtures, ANNEX II, 2.3). The measured rate constant for biodegradation and mineralization are all > 0.043 d-1. Therefore, according to CLP criteria, TEA is rapidly biodegradable. These results also lead to the conclusion, that TEA is readily biodegradable. Hence, TEA degrades rapidly in the environmental compartments water, sediment and soil.

Also DEA was found readily biodegradable in an OECD 301F screening test.

From these data it can be concluded that the multiconstituent substance is also readily biodegradable.