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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

2-ethylhexanol was readily biodegradable in a MITI-I Test, (equivalent to OECD TG 301-C, reliability category 1). This is in line with the observation that the chemical oxygen demand (COD) was reduced by >95%  in the  Zahn-Wellens test (OECD 302B guideline; reliability 2)  within 5 days demonstrating rapid biodegradation. 

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Data contained in Japanese government's report (pre-guideline and pre-GLP, however equivalent to OECD 301 C and compliant to a GLP-similar system used then in Japan) demonstrate reliably (RL 1) that 2-ethylhexanol is readily biodegradable in the MITI test I (OECD TG 301 C), as evidenced by complete removal of TOC (100%) and test substance (100%, measured using GC-FID) within 2 weeks. The degradation by BOD (O2 consumption) was reported as 99.9 % and 79.0 % in this study (duplicate samples). The starting chemical concentration was 100 mg/L and concentration of activated sludge was 30 mg/L (NITE, 1977).

In a reliable (with restrictions) supporting study on inherent biodegradability the chemical oxygen demand (COD) of 2 -Ethylhexanol was reduced by >95% (Zahn-Wellens-test, OECD 302B) within 5 days. Kinetic of test substance (in %; Hoechst, 1979):

 Day  % degraded
 1  23
 2  36
 5  96
 7  97
 9  96

Further not assignable (RL 4) studies on inherent biodegradabiltity showing similar results are in support of these data.