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EC number: 205-594-7 | CAS number: 143-24-8
BIODEGRADATION IN WATER: SCREENING TESTS
Read across justification for the of use the Diglyme test
Dimethylated glycols and polyglycols are not readily biodegradable. Obviously microorganism can not easily cleave the O-Methyl bond. Nevertheless Diglyme can be biodegraded under inherent conditions, e.g. Zahn-Wellens test OECD 302 B.
Monomethylated glycols on the other hand can be biodegraded rapidly. An example is the monomethylated triglycole (TEGME,CASNo 112-35-6) which is readily as well as inherently biodegradable ((MSDS Dow, 2007, Hoechst 1986, W 86-223).
Based on the facts given above it is reasonable to use the data on inherent biodegradation of Diglyme (REACH Registration No. 01-2119485900-34-0000) also for Tetraglyme.
It can be concluded from these facts that rapid biodegradation of dimethylated glycols can occur when one of the methylgroups is cleaved off. This also means that Tetraglyme is not a recalcitrant substance.
Details on the biodegradation sceening test of Diglyme (REACH Registration No.01-2119485900-34-0000)
For the determination of the primary biodegradation the test item was tested at a concentration of 600 µg/L in duplicates. The primary biodegradation was determined by SPME GC/MS analysis of the test item. For the determination of the inherent biodegradation the test item was tested at a concentration of 95 mg/Lin duplicates, corresponding to a DOC of 51.3mg C/L in the test vessel. The inherent biodegradation of the test item was followed by determination of DOC. The ratio of eliminated DOC, corrected for the control at each time interval to the initial DOC value is expressed as the percentage biodegradation at each sampling date.
In order to check the activity of the test system diethylene glycole in a concentration of 120 mg/L was used as functional control. After 14 days a degradation rate of 100 % was reached.
The physico-chemical elimination (volatilisation) of the test item was monitored in separate sterile controls. At the test item concentration of 95 mg/L a sterile control without inoculum and poisoned with HgCl2was used. For determination of the primary biodegradation sterile controls (with inoculum and poisoned with HgCl2) with a test item concentration of 300 µg/L and 600 µg/L were tested. No physico-chemical elimination (volatilistion) occurred in the sterile controls until test end.
The primary degradation started after an adaptation phase of 16 days. The biodegradation was fast and on day 23 the pass level of 70 % was reached. After 28 days the primary degradation came to 95 %.
The inherent degradation started after a long lasting adaption phase of 21 days. The biodegradation was fast and the biodegradation reached the 70 % pass level after 29 days. After 36 days a biodegradation of 99 % was reached.
The test item is classified as primary biodegradable after 23 days and inherent biodegradable after 29 days.
Table 1: Primary and Inherent Biodegradability of the Test Item Diethylenglykoldimethylether in Comparison to the Functional Control and the Sterile Control
Inherent Biodegradation / Elimination [%]
test item95 mg/L
functional control120 mg/L
Sterile control*95 mg/Ltest item
Primary Biodegradation / Elimination [%]
Test item600 µg/L
Sterile control*600 µg/L test item
Sterile control*300 µg/L test item
BIODEGRADATION IN WATER: SIMMULATION TESTS
Tetraglyme is not readily but inherently biodegradable. It is not expected that the DT90 of Tetraglyme in an OECD 308 or 309 would indicate a rapid biodegradation in sediment and surface water e.g. < 100 d. Due to the fact that Tetraglyme is classified R62 strict risk reduction measures have to be applied which means that release to the environmental compartments have to be minimized. Based on these facts the simulation tests according OECD 308 and 309 are not warranted.
BIODEGRADATION IN SOIL
The Exposuire Modelling program calculates for the Koc of Tetraglyme 3.8 L/kg (non hydrophobic substances). Due to the low estimated Koc of Tetraglyme a transfer to agricultural soil via sewage sludge can be neglected. Indirect exposure via deposition from air is unlikely as Triglyme is readily photodegraded in air. Because of the low soil exposure by Triglyme a soil biodegradation study is not warranted. The statement given above fulfills the requirement for waiving as given in 1907/2006/EC Annex IX, Column 2, 220.127.116.11: "The study need not be conducted if direct and indirect exposure of soil is unlikely."
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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