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Environmental fate & pathways

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One experimental study according to OECD 301C confirmed that aminoiminomethanesulphinic acid (CAS No. 1758-73-2) is readily biodegradable according to the OECD criteria (80.6% biodegradation after 28 d). Aminoiminomethanesulphinic acid was found to be unstable under alkaline conditions forming urea and sulfoxylate ion, SO2-. Considering the high water solubility (27 g/L) and the low potential for adsorption to organic soil and sediment particles (log Koc: -0.96 - 0, KOCWIN v2.00), the main compartment for environmental distribution is expected to be the surface water. Nevertheless, persistency in this compartment is not expected since the substance is readily biodegradable and it will be rapidly and ultimately degraded in sewage treatment plants and natural waters. Evaporation from the water phase into air and the transport through the atmospheric compartment is not expected in significant amounts for aminoiminomethanesulphinic acid based on the low vapour pressure of 0.000161 Pa at 25 °C. However, if released into air, aminoiminomethanesulphinic acid is susceptible to indirect photodegradation by OH-radicals with a DT50 value of 18.22 h (AOPWIN v1.92). Therefore, the potential for accumulation in air and the subsequent transport to other environmental compartments is low. The potential for bioaccumulation of aminoiminomethanesulphinic acid is assumed to be low based on the log Kow of -3.38.