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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information



In an inherent biodegradation study (modified Zahn-Wellens) in industrial, aerobic, non-adapted activated sludge, the degradation of the hydrolysis products of dimethyl sulphate is reported to be 80% after 15 days. Details of this study are not available.

In a recently performed Modified OECD Screening Test (301 E) with a municipal/industrial activated sludge, DMS (and hydrolysis products) was found to be ready biodegradable (Industry report 1998). An important deviation from the OECD test protocol was that the inoculum was pre-exposed to the test concentration. The relevance of this test is therefore limited to industrial Sewage Treatment Plants (STPs) (regular DMS inflow).

It is difficult to classify DMS into one of the current biodegradation categories on the basis of the above-mentioned information. It should be noticed, however, that the high hydrolysis rate of the substance would anyhow lead to a high removal percentage of DMS in an STP in the present risk assessment. DMS will be regarded as readily biodegradable in industrial STPs.

Recently another biodegradation test result became available. In an OECD 301B, CO2Evolution Test MMS was found to be ready biodegradable (Hoechst Marion Roussel report, 1998a). This result supports the OECD 301 E test result for DMS.