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Environmental fate & pathways

Biodegradation in soil

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Due to exposure considerations, further simulation testing for biodegradation in water and sediment is not required.

The substance is solely used as an intermediate to manufacture other substances, mainly polymers, performed in closed industrial processes. During these intermediate uses the substance is fully consumed. These intermediate uses are under full supervision of environmental legislation at industrial sites and releases of the substance to the environment are negligible. No professional uses or consumer uses do exist, nor are there any service life scenarios to be considered, as the substance is an intermediate. Hence, there is no significant exposure to the environment.
All RCRs derived for the intermediate uses (fresh water, marine water, sediment, sewage treatment plant and agricultural soil) are below 0.01 and thus, far from any risk to any of the environmental compartments, even without consideration of a biological treatment of this inherently degradable substance (see exposure scenarios). It should be noted that the substance was found being inherently biodegradable when exposed to sewage sludge from a municipal sewage treatment plant but degradation of 90% was achieved, when exposing effluent water to an adapted sewage sludge, as common in industrial settings (see supporting study, Hoechst AG). Thus, in an industrial setting, associated with on-site sewage treatment plant, the substance is considered being readily biodegradable (see REACH Annex IX waiving argument for this study in column 2). Basis for the RCRs documented in the exposure scenarios for the environment are the PNECs derived from currently available acute ecotox study data, but also data from substance concentrations in effluent data derived from an industrial site (higher tier data). So, the current assessment as outlined in the exposure scenarios for the environment are based on absolute worst-case assessments.
Furthermore, it should be recognized that the substance is ionic, having a negative log Pow (-1.01) and thus, no adsorptive capacity to bind to sediment or soil. Additionally, the substance, as well as industrial sewage sludge (e.g. from industrial sewage treatment plants) that could potentially contain the substance are not applied (e.g. as fertilizer) to soil. Also, due to the negligible vapour pressure (6.4 10E-7 Pa), volatilization and deposition to soil via air can be excluded.
By ECHA decision number CCH-D-2114554616-43-01/F long-term ecotox studies were requested, currently being performed and it is expected that the outcome of these studies will allow to reduce the safety factors, resulting in even higher PNECs for the environmental compartments and thus, even lower RCRs (PNEC for agricultural soil are derived by the equilibrium partitioning method).
Based on all reasons provided above, including worst-case exposure considerations, no simulation testing for biodegradation in soil is required.

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