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Environmental fate & pathways

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Release to air, with an estimated vapour pressure of 10 -32 Pa at 25 deg C, indicates that Direct Brown 44 will not exist if not in dust particles in the atmosphere. In vapour-phase it will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 0.6 hours; degradation in sunlight also occurs . If released to soil, it is expected to have very high mobility based upon a measured Koc of 1. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 10E-39 atm-cu m/mole. The substance is not ready biodegradable. If released into water, it is not expected to adsorb to suspended solids and sediment based upon the measured Koc. Estimated volatilization half-lives for a model river and model lake are 10E40 days. An estimated BCFof 3 suggests the potential for bioconcentration in aquatic organisms is low. Direct Brown 44 doesn’t hydrolyze easily.