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Ziegler Bottoms are characterized as comprising of two primary constituents; icosan-1-ol and docosan-1-ol. Together these constituents represent a structural class of components (alcohols) that constitute approximately 82% of the composition of Ziegler Bottoms. Study data, where available, for each of the primary constituents has been evaluated and considered together. In a conservative approach the most sensitive study result from across the two constituents has been identified and used to adequately address the Ziegler Bottoms endpoint in question.

Reliable studies (Klimisch score 2) were performed in accordance with OECD Guideline 301B (Ready Biodegradability: CO2 Evolution Test) on the two primary constituents of Ziegler Bottoms, icosan-1-ol and docosan-1-ol. 88.4% and 87.9% of icosan-1-ol and docosan-1-ol respectively degraded after 28 days with an unacclimated sewage sludge inoculum. The test substances also achieve 60% degradation with a 10-day window indicating ready biodegradability. As both constituents are readily biodegradable, Ziegler Bottoms can also be regarded as readily biodegradable. Minor residual constituents which include, ethers, esters and alkanes are also expected to degrade rapidly.

Annex IX column 2 of the REACH Regulation states that a study on the Biodegradation in Water and Sediment and a study on Biodegradation in Soil do not need to be conducted if the substance is readily biodegradable. Therefore, a study on Biodegradation in Water and Sediment and a study on Biodegradation in soil do not have to be conducted for Ziegler Bottoms.