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Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
03.08.1999 - 11.02.2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study, GLP
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Version / remarks:
) adopted 17 July 1992 and EU Method C.4-C, 31 July 1992
Deviations:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Type: inoculum was collected from a water treatment plant containing effluent from a predominantly domestic origin.
Collected from: the water treatment plant Emeraude (SIARR) (76141 Petit-Quevilly, France).
Sampling date: 28 July 1999.
Preparation: the inoculum was prepared by initially sieving sewage sludge and centrifuging three times for at least 5 minutes. For each centrifugation, the supernatant was rejected and the pellet was redispersed in the mineral medium.

In order to wash out the dissolved organic carbon (DOC) and to lower the carbon organic content, the inoculum was preconditioned for 7 days
before use. Air was bubbled through the inoculum during this preconditioning period.
Duration of test (contact time):
28 d
Initial conc.:
48 mg/L
Based on:
act. ingr.
Initial conc.:
10 mg/L
Based on:
other: TOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
Conditions during the test
Temperature: 20 -24°C.
lllumination: the test was carried out in dark glass bottles fitted with dark glass stoppers and aeration tubes to reduce the quantity of light reaching
the test suspensions.
Duration of the test: 28 days.
Culture homogeneity: in order to homogenize the solution, all test suspensions were agitated using magnetic stirrers.
Aeration: air was bubbled through each parallel at the rate of 30 - 100 mVmin (checked daily and reset if necessary) during the test.
pH: was measured before the beginning of the test in the mineral medium and at the end of the test in all test suspensions .
Loading: test vessels were loaded at 3 litres of suspension per flask.

Treatment
Five flasks were used for the test:
two flasks containing the inoculum (inoculum blanks),
two flasks containing the test substance (at 10 mg/I of TOC) and inocu!um (test so!utions),
one flask containing the reference substance (sodium acetate at 10 mg/I of TOC) and inoculum
(procedure control).

Parallel groups were prepared by adding 2.4 litres of mineral medium to each of the test flasks. Inoculum was added to provide a final concentration of 11 mg/I of suspended solids (dry weight) in 3 litres of suspension.
The test flasks were aerated with CO2 scrubbed air overnight to purge the system of carbon dioxide and then attached in parallel to a series of threewash bottles filled with 100 ml of 0.0125 M barium hydroxide solution (to trap any C02 released from the test vessels). The test
and reference (sodium acetate) substances were added, as appropriate, to the flasks to give a test and reference substance concentrations of 10 mg of TOC per litre. When all the substances had been added, the volume of the suspensions was made up to 3 litres. Carbon dioxide-scrubbed air was bubbled through the suspensions at the same rate for all preparations.
Reference substance:
acetic acid, sodium salt
Parameter:
% degradation (CO2 evolution)
Value:
91
Sampling time:
28 d
Parameter:
% degradation (CO2 evolution)
Value:
65
Sampling time:
16 d
Remarks on result:
other: End of 10 day window
Details on results:
Tbe 1O-day window (the 10 days irnrnediately following the attainment of 10% biodegradation) started on the 6th day. Biodegradation of the test substance BUTYL DIGLYCOL METHACRYLATE totalled 65% at the end of this 10-day window (16th day) and 91% at the end of the test.

Under our experimental conditions, the test substance BUTYL DIGLYCOL METHACRYLATE
was readily biodegradable in a 28-day modified Sturm test.

Cumulative percentage of biodegradation

 

Test substance

Reference substance

Day

No. 1

No. 2

Average

1

0.90

3.10

2.00

3.50

4

1.20

7.19

4.20

16.78

5

4.70

11.39

8.04

29.67

6

5.89

13.09

9.49

34.17

8

13.14

23.73

18.43

38.22

12

36.17

49.06

42.61

53.95

14

51.05

62.54

56.80

62.44

16

60.10

70.39

65.24

67.89

18

64.14

76.63

70.39

72.33

21

69.99

81.68

75.83

76.08

25

77.43

86.42

81.93

81.23

28

87.57

93.66

90.62

94.26

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
The ready biodegradation of Butyldiglycol methacrylate was investigated in a CO2 evolution test over a period of 28 days and using domestic sewage as inoculum. Inoculum blank and procedural/functional control with the reference substance sodium acetate were performed.
The 10-day window started on day 6. Biodegradation totalled 65% at the end of the 10 day window (day 16) and 91% at the end of the test period. The test item proved to be readily biodegradable and fulfilling the 10-d window criterion.
Executive summary:

The ready biodegradation of Butyldiglycol methacrylate was investigated in a study conducted according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) adopted 17 July 1992 and EU Method C.4-C, 31 July 1992, over a period of 28 days using sewage sludge sampled from the aeration tank of a predominantly domestic sewage treatment plant as inoculum. The biodegradation rate was determined by measurement of CO2 evolution. Inoculum blank and procedural/functional control with the reference substance sodium acetate were performed.

After 28 days the degradation of Butyldiglycol methacrylate reached 91 %.The functional control reached the pass level >60% after 14 d.

This study is regarded as reliable without restriction and satisfies the guideline requirements for ready biodegradation. Butyldiglycol methacrylate proved to be readily biodegradable and fulfilling the 10-d window criterion.

NOTE: Any of data in this dataset are disseminated by the European Union on a right-to-know basis and this is not a publication in the same sense as a book or an article in a journal. The right of ownership in any part of this information is reserved by the data owner(s). The use of this information for any other, e.g. commercial purpose is strictly reserved to the data owners and those persons or legal entities having paid the respective access fee for the intended purpose.

Description of key information

Butyldiglycol methacrylate is classified as readily biodegradable. The 10-day criterion for ready biodegradability was met.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

The ready biodegradation of Butyldiglycol methacrylate was investigated in a study conducted according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test) adopted 17 July 1992 and EU Method C.4-C, 31 July 1992, over a period of 28 days using sewage sludge sampled from the aeration tank of a predominantly domestic sewage treatment plant as inoculum. The biodegradation rate was determined by measurement of CO2 evolution. Inoculum blank and procedural/functional control with the reference substance sodium acetate were performed.

After 28 days the degradation of Butyldiglycol methacrylate reached 91 %.The functional control reached the pass level >60% after 14 d.

This study is regarded as reliable without restriction and satisfies the guideline requirements for ready biodegradation. Butyldiglycol methacrylate proved to be readily biodegradable and fulfilling the 10-d window criterion.