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BIODEGRADATION IN WATER: SCREENINGTESTS

The primary and inherent biodegradability were determined in the Zahn-Wellens-Test / EMPA Test with a non adapted activated sludge for the test itemMonoethylenglykoldimethylether over a period up to 48 days. The study was conducted from 2010-05-05 to 2010-06-22 according to OECD 302 B at Dr. U. Noack-Laboratorien.

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/L in duplicates, corresponding to a DOC of 50.4mg 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.

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 at 95 mg/L until test end. At the concentration 300 µg/L and 600 µg/L the physico-chemical elimination (volatilisation) was in the range 29 - 34% on day 7. Until test end the mean volatilisation reached a maximum of 37 %.

The primary and inherent biodegradability of the test item in comparison to the degradable functional control and the elimination in the sterile controls is given in the Table below.

For the calculation of the primary biodegradation, the concentration of the test item replicates was corrected for the mean elimination of the sterile control values. The primary degradation started after a long lasting adaptation phase of 39 days. The course of the biodegradation was slow and on day 48 a biodegradation of only 14 % was reached.

The inherent degradation started after a long lasting adaption phase of 26 days. The course of the biodegradation was slow and the biodegradation did not reach the 70 % pass level. After 48 days a biodegradation of 16 % was reached.

Primary and inherent Biodegradability of the Test Item Monoethylenglykoldimethylether in Comparison to the Functional Control and the Sterile Control

Primary and inherent Biodegradation / Elimination [%]

Replicate

7

14

21

26

28

35

48

test item

95 mg/L

5

1

3

10

11

12

16

functional control

120 mg/L

99

97

100

100

100

98

100

Sterile control1)

95 mg/Ltest item

0

0

0

0

0

0

0

Test item2)

600 µg/L

-7

-1

2

-

5

-

14

Sterile control1)

300 µg/L test item

34

28

22

-

38

-

37

Sterile control1)

600 µg/L test item

29

31

46

-

35

-

36

This is supported by two other screening tests (OECD 302B) which shows also no inherent Biodegradability under the test conditions.

BIODEGRADATION IN WATER: SCREENING TESTS

Monoglyme is neither readily nor inherently biodegradable. Stripping from aqueous solution is considerable (almost complete loss from an aqueous solution with 5 g/l Monoglyme during 24 h) which is important for the loss in Sewage treatment plants. It is not expected that the DT90 of Monoglyme 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 Monoglyme 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 US EPA property estimation program KOCWIN V2.00 calculates for the Koc of Monoglyme 2.4 L/kg (Molecular Connectivity Index) or 4.2 L/kg (beased on Log Kow of -0.21. Due to the low estimated Koc of Monoglyme a transfer to agricultural soil via sewage sludge can be neglected. Indirect exposure via deposition from air is unlikely as Monoglyme is readily photodegrated in air. Because of the low soil exposure by Monoglyme 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, 9.2.1.3: "The study need not be conducted if direct and indirect exposure of soil is unlikely."