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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

In accordance with column 2 of REACH Regulation 1907/2006/EC Annex IX section 9.2.1.2, the study “Biodegradation in water: simulation test” does not need to be conducted as the test substance can be regarded as inorganic.
A biodegradation study (screening test) with sodium cyanate was conducted but It was not technically feasible to calculate the ready biodegradation parameters.

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Additional information

DOC (dissolved organic carbon) measurement must be made for the assessment of degradation. DOC is the TOC of a filtrated solution. The content of TOC (total organic carbon) is determined by measuring the TC (total carbon) and the IC (inorganic carbon). Then the content of organic carbon is calculated as difference between TC and IC. When measuring the inorganic carbon (IC) in the carbon analyser, the CO2 is driven out by adding phosphoric acid. Under these acidic conditions, the cyanate of the test item is partly decomposed.

A determination of the biodegradation based on total carbon in the test vessels isn’t possible because the test item contains 5 % carbonate. Therefore a differentiation between carbon from cyanate and carbon from carbonate and hydrogencarbonate wasn’t possible.

Furthermore within the study, a significant reduction of the TOC was observed after three hours. Without much doubt the cyanate was degraded by abiotic processes and decomposed to CO2 and NH3.

Therefore a determination of the ready biodegradability isn’t possible.