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Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The hydrolysis of MEKO was dependent on pH, but much less dependent on temperature. At pH 4, MEKO was hydrolytically unstable, regardless of the temperature (t1/2 < 0.3 min), at pH 7, the hydrolysis reaction is much slower; 14% hydrolysis at 20 °C was obtained after 4 days and 44% hydrolysis was obtained at 50 °C after 7 days and at pH 9, no measurable hydrolysis under any of the test conditions was observed. Since from the above results no DT50 could be determined at pH7 in the assessment it is assumed that MEKO is not hydrolysable.

The abiotic degradation rate constants used in the assessment of MEKO are:

Degradation rate constant for hydrolysis

6.93E-07 d-1

Degradation rate constant for photolysis

6.93E-07 d-1

Degradation rate constant in air

0 d-1

Biotic degradation

MEKO does not meet the requirements for ready biodegradation in an OECD 301 C guideline study, but is considered inherently biodegradable when evaluated in an OECD 302 B guideline study. As the specific criteria for inherent biodegradation are passes, in the assessment MEKO is characterised as “Inherently biodegradable, fulfilling specific criteria”.

The biotic degradation rate constants used in the assessment of MEKO are:

Degradation in the STP

2.4 d-1

Degradation rate in water

4.62E-03 d-1

Degradation rate in bulk sediment

2.31E-04d-1

Degradation rate in bulk soil

2.31E-03 d-1