Aniline

Endpoint summary

Additional information

Abiotic degradation:

Half lifes for the direct and indirect photochemical degradation of Aniline in the atmosphere and the top layer of surface water are short.The assessment of photodegradation using AOP v1.92 revealed a half life of 3.6 hours for aniline in the atmosphere. Furthermore, under favoured light conditions, photolysis is an important elimination path near the water surface.The available studies show that aniline is photolytically degraded within about 4 to 11 h under spring or summer conditions in the top layer of surface waters.However, it was found that, regarding the total water body, biodegradation should be the major elimination pathway in the hydrosphere.

Biotic degradation:

Aniline is readiliy biodegradable (according to OECD criteria). Furthermore, in surface water biodegradation studies, primary degradation and mineralization was measured using environmentally relevant test substance concentrations. Degradation rates of > 80% were measured within a few days underlining the readily biodegradability of aniline. In sediment and soil, two competing processes are at hand, biodegradation and the formation of non-hydrolyzable covalent bonds to humic substances. This binding leads to long half lifes for bound aniline of 350 and 3500 days for soil and sediment, respectively. In EU-Risk Assessment report (2004) it was assumed that approximately, 80% of Aniline is covalently bound in soil. Measurements in sediment tests gave a similar observation.

Distribution:

Adsorption measurements on soil and sewage sludge revealed moderate adsorption properties of aniline (log Koc < 3). However, it should be considered, that in soil, two competitive reactions occur: biodegradation and formation of covalent bounds onto the organic matter. The latter pathway leads to aniline-humic acid adducts, which are immobile and only slowly degraded. Thus accumulation of the reaction product with humic substances occurs. The fate in sediments is considered to be similar than in soils. The formation of covalent bonds with humic matter is a general property of aniline and its derivatives. With a Henry's law constant in the range of 0.1-0.2 Pa m3 mol-1, aniline is expected to be low volatile from aqueous solution. A calculation of the environmental distribution, using Mackay Level 1, revealed that the target compartment after release will be the hydrosphere.

Bioaccumulation:

Both, a measured BCF of 2.6 ± 0.06 in Danio rerio and a log Kow of 0.9 indicate no bioaccumulation potential of aniline. This is supported by measurements on Lumbriculus variegatus revealing accumulation factors < 1.