Registration Dossier

Environmental fate & pathways

Additional information on environmental fate and behaviour

Administrative data

Endpoint:
additional information on environmental fate and behaviour
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2008-12-02 to 2009-01-27
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted according to GLP and following ISO 11734 (1995) testing guideline.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: ISO 11734 (1995)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study / information:
Information on the biodegradation of SLI(76) stripped in digested sludge

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Name of test material as cited in test report: SLI (76) Stripped.

Results and discussion

Any other information on results incl. tables

The study was terminated after 56 days. The TIC measured in the liquid phase of two of the control bottles was below the calibration range, so these results were omitted from the calculations.   Percentage biodegradability data are given in Table 2. The mean final level of biodegradation achieved by the reference substance, PEG-400, was 80%, indicating that the sludge contained viable organisms. The mean final level of biodegradation achieved by SLI(76) Stripped was 67% in the 100 mg C/L bottles and 75% in the 50 mg C/L test bottles. There was some variation in gas production between replicates during the study, but, in most cases, there was Iittle difference between the final biodegradation results, as the bottles where higher gas pressures were measured tended to have lower TIC measurements. The exceptions to this were the SLI(76) Stripped at 50 mg C/L, where there was a large difference between the calculated percentage biodegradation in the three replicates, but this may be partly due to increased errors in the calculated values at the lower test concentration.   The organic carbon of the PEG 400 stock solution measured on day 0 of the study was 4910 mg C/L, and of the SLI(76) Stripped stock solution was 4750 mg C/L. These values are within 5% of the nominal value of 5000 mg C/L.   The Redox indicator (Resazurin) showed pink coloration in only two of the control bottles after day 7, and this had disappeared by day 13, so it is considered that anaerobic conditions were maintained throughout the study.   All the measured pHs at the start of the study were between 7.0 and 7.1, and on day 56 were in the range 6.4 to 6.7.

Table 2: Mean biodegradability

Sample description

Bottle No

dP

(bar)

Carbon (mg)

Biodegradation (%)

Headspace

Inorganic in liquid phase

Total

-

Mean

Control

2

0.139

3.91

1.76

5.67

-

-

3

0.104

2.92

2.24

5.16

-

-

4

0.242

6.80

<1.0

<7.8

-

-

16

0.149

4.19

1.94

6.13

-

-

17

0.118

3.32

2.43

5.75

-

-

18

0.224

6.30

<1.0

<6.3

-

-

PEG 400 (100 mg C/L)

6

0.337

9.48

3.90

13.4

77

80

7

0.338

9.50

4.13

13.6

79

8

0.418

11.8

2.26

14.1

84

SLI(76) stripped (100 mg C/L)

10

0.379

10.7

1.30

12.0

63

67

11

0.333

9.36

3.39

12.8

71

12

0.397

11.2

1.09

12.3

66

SLI(76) stripped (50 mg C/L)

13

0.192

5.40

2.73

8.13

49

75

14

0.352

9.90

1.20

11.1

108

15

0.231

6.50

2.52

9.02

67

dP Cumulative gas pressure readings

Applicant's summary and conclusion

Conclusions:
SLI(76) Stripped showed extensive biodegradation during the study reaching 67% by day 56 in the 100 mg C/L bottles, and 75% biodegradation in the 50 mg C/L bottles. The reference substance, PEG 400, also showed extensive biodegradation during the study, reaching 80% by day 56, showing the inoculum was behaving normally.
Executive summary:

The anaerobic biodegradability of SLI(76) stripped was determined according to GLP and ISO 11734 (1995) guideline. SLI(76) Stripped showed extensive biodegradation during the studyreaching 67% by day 56 in the 100 mg C/L bottles, and 75% biodegradation in the 50 mg C/L bottles. The reference substance, PEG 400, also showed extensive biodegradation during the study, reaching 80% by day 56, showing the inoculum was behaving normally.