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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 2011-12-21 to 2012-03-28
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: Testing Methods for New Chemical Substances; No. 0331-7, Ministry of Health, Labour and Welfare; 2011.03.29, No. 5, Ministry of Economy, Trade and Industry; No. 110331009, Ministry of Environment, Japan.
Deviations:
no
GLP compliance:
yes

Test material

Constituent 1
Details on test material:
- Name of test material (as cited in study report): PSF-58
- Physical state: white crystalline powder
- Analytical purity: 100%
- Lot/batch No.: KNC110310
- Stability under test conditions: stable for 2 years in ambient temperature

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: standard activated sludge purchased from Chemicals Evaluation and Research Institute, Japan
- Laboratory culture: cultured at the test facility in 25 °C (± 2 °C), not less than 5 mg/L dissolved oxygen and pH 7 (± 1).
- Concentration of sludge: 2979 mg/L
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimationopen allclose all
Parameter followed for biodegradation estimation:
O2 consumption
Parameter followed for biodegradation estimation:
test mat. analysis
Details on study design:
TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 25.0 °C
- pH: 6.78 - 6.92 (sludge + test substance), 5.92 (water + test substance)
- pH adjusted: yes
- Suspended solids concentration: 30 mg/L

TEST SYSTEM
- Culturing apparatus: test flasks with a fill volume of 300 mL
- Number of culture flasks/concentration: 3
- Measuring equipment: Coulometer Type OM-2001A, Ohkura Electric Co., Ltd

SAMPLING
- Sampling frequency: (BOD) continuous
- Sampling method: (BOD) manometric method equipped with Coulometer

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 1 replicate
- Abiotic sterile control: no
- Toxicity control: no
- Other: Abiotic control: yes, 1 replicate; Activity control: yes, 1 replicate
Reference substance
Reference substance:
aniline

Results and discussion

Test performance:
This test is valid because the differences between the maximum and the minimum in the degradation rates of " sludge + test substance " were less than 20% ( 5% from BOD, 4% from direct determination ( LC ) and 6% from TOC ), and the degradation rate of activity control substance, aniline, calculated from BOD was not less than 60% ( 83% ) after 14 days exposure.
% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
1
Sampling time:
28 d
Remarks on result:
other: BOD, mean of three replicates
Parameter:
% degradation (test mat. analysis)
Value:
19
Sampling time:
28 d
Remarks on result:
other: LC-analysis, mean of three replicates
Parameter:
% degradation (TOC removal)
Value:
11
Sampling time:
28 d
Remarks on result:
other: TOC analysis, mean of three replicates

BOD5 / COD results

Results with reference substance:
83% after 14 d, 60% pass level was reached

Any other information on results incl. tables

Table 1: Degradation rates based on oxygen consumption

 

 

 

7th day

14th day

21st day

28th day

Test solutions

Amount of test substance added [mg]

TOD [mg]

BOD [mg]

Degradation rate

BOD [mg]

Degradation rate

BOD [mg]

Degradation rate

BOD [mg]

Degradation rate

Sludge + aniline

29.9

89.9

69.6

73

80.4

83

83.0

84

86.3

86

Control blank

-

-

4.2

-

6.1

-

7.6

-

9.1

-

Sludge + test substance

30.0

37.8

4.2

0

3

7.5

4

7

8.7

3

5

8.7

-1

1

Sludge + test substance

30.0

37.8

5.0

2

8.2

6

9.6

5

9.6

1

Sludge + test substance

30.0

37.8

6.5

6

9.7

10

10.5

8

10.5

4

Water + test substance

30.0

-

0.0

-

0.1

-

0.1

-

1.2

-

Table 2: Material balance by direct determination (LC-analysis)

Test solutions

Residual rate of test substance [%]

Production rate of transformation product 1 [%]

Production of transformation product 2 [%]

Material balance [%]

Sludge + test substance

83

9

0

92

94

Sludge + test substance

86

11

0

97

Sludge + test substance

82

10

0

92

Water + test substance

104

0

0

104

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The test substance was not readily biodegradable in the test.
Executive summary:

The biodegradation test was conducted in accordance with OECD 301C.

From results of oxygen consumption (BOD) measurement, the degradation rate was 1 % on average.

From results by LC analysis, the residual rate of test item was 84% on average in "sludge + test substance" and 104% in "water + test substance ", and the degradation rate of test item was 19% on average.

From results by IC analysis, the production rate of sulphate ion was 15% on average in "sludge + test substance" and 0%"' in "water + test substance ".

From results by total organic carbon (TOC) measurement, the residual rate was 98% on average in "sludge + test substance " and 110% in " water + test substance ", and the degradation rate was 11 % on average.

It is concluded from these results that the test substance was not readily biodegradable in the test.