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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Test substance EC 907 -996 -4 (Reaction mass of 3,6,9,12 -tetraoxahexadecan-1 -ol and 2 -(2 -(2 -butoxyethoxy)ethoxy)ethanol: OECD301D: 76% in 28days, Readily biodegradable

Test substance CAS 9044-77-3 (Poly(oxy-1,2,-ethanediyl), α-butyl, ω-hydroxyl) OECD301D; 69% in 28 days, Readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

In a guideline (OECD 301D) and GLP ready biodegradability study, a substance corresponding to the description "Reaction mass of 3,6,9,12 -tetraoxahexadecan-1 -ol and 2 -(2 -(2 -butoxyethoxy)ethoxy)ethanol" gave a positive result (>60% degradation relative to the COD value) with a maximum of 76% biodegradation recorded on day 28. In a similar GLP study to the same protocol, the substance "Poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy" attained 69% degradation after 28 days. Both substances are glycol ethers consisting predominantly of 3 -4 units of ethylene oxide and butanol. The results indicate that these and similar substances can be considered as ready biodegradable under the strict terms of this definition. The BOD5 value for this substance (nominal concentration 50 mg/l) was determined to be 3.23 mg O2/L. The COD value for BP DCP 208 was determined to be 97.33 mg O2/L

All of these substances are oligomers of they ethylene glycol butyl ether series, with the main components being tri, tetra and pentaethylene glycol ethyl ethers. The tetra (the subject of this registration) is typically 15-25% of the composition. All three main components are expected to show similar biodegradability and therefore the result for the 'mixture' can be considered representative of all three main components individually. This is supported by the results from the Biowin QSAR which predicts that all three substances will be readily biodegradable. On this basis, it is concluded that tetraethylene glycol butyl ether is considered readily biodegradable.