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Environmental fate & pathways

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After release into the environment, IBDU may be rapidly degreaded by photodegradation in air. However, the main sink for IBDU will be biodegradation in water or soil (substance is readiliy biodegradable according to OECD criteria). IBDU is potentially susceptible to hydrolysis. Hydrolysis of IBDU will be influenced by pH. Measurements gave an increase of total nitrogen and urea nitrogen in the solution as pH decreased. Through its use as slow-release fertilizer, IBDU granules are directly applied on soil. In soil, dissolved IBDU is hydrolyzed to urea and isobutyraldehyde (Hamamoto, 1966). Both substances are at least inherently biodegradable. Urea is decomposed by urease into NH3 and CO2 (ammonification) and NH3 then protonated into the ammonium ion. The latter volatilizes or is oxidized via nitrite into nitrate (nitrification). Low pH (pH 6), high temperatures, high soil moisture and small granular size increase solubilisation of IBDU and, hence, mineralization (Hamamoto, 1966; Hughes, 1976; Markova, 1978).

Due to the low log Pow (-0.903), accumulation in organisms is not to be expected. Furthermore, the substance is not expected to adsorb to suspended solids and sediment. When dissolved in water the substance will not significantly evaporate into air (Henry´s Law constant < 1 Pa m3/mol). In general, the main target for environmental distribution will be water (Mackay Level 1 calculation, BASF AG 2004).