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Environmental fate & pathways

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:
29.10.1998-26.11.1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
GLP compliance:
yes
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 98/Ba736/1 11 09 98
- Expiration date of the lot/batch: not specified
- Purity test date: not specified

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room tempearture, away from moisture
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: no solubility
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: not reported

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: not specified
- Preliminary purification step (if any): not needed
- Final dilution of a dissolved solid, stock liquid or gel: not applicable
- Final preparation of a solid: not applicable
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): The source of test organisms was activated sludge freshly obtained from a municipal sewage treatment plant: Chantilly 60, France, receiving predominantly domestic sewage.
- Storage conditions: used immidiately
- Storage length: used immidiately
- Pretreatment: The freshly obtained sludge was used immediately. The concentration of suspended micro-organisms was determined to be 1.10^5 /mL in the concentrated sludge. Before use, the sludge was allowed to settle and the supernatant liquid was used as inoculum at the amount of 30 mL/L of mineral medium.
- Initial cell/biomass concentration: 1.10^5 micro-organisms/mL
Duration of test (contact time):
ca. 28 d
Initial conc.:
>= 10 - <= 20 mg/L
Based on:
TOC
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Composition of medium: see table 1 below
- Additional substrate: not specified
- Test temperature: ca. 20C
- pH: 7.55
- pH adjusted: not specified
- CEC (meq/100 g): not specified
- Aeration of dilution water: CO2 free compressed air
- Suspended solids concentration: not specified
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions:
- Method used to create anaerobic conditions:
- Measuring equipment:
- Details of trap for CO2 and volatile organics if used:

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes
Reference substance:
aniline
Key result
Parameter:
% degradation (CO2 evolution)
Value:
ca. 27
St. dev.:
3
Sampling time:
28 d

Table 1: CO degradation

Day CO2 Degradation Cumulative CO2 production Theoretical CO2 %
  Blanks Assay Assay Assay
  FB1+FB2 FB3 FB average FB9 FB10 FB total FB9 FB10 FB total FB9 FB10 FB average FB total
1 2.09 5.28 3.66 1.65 1.98 3.74 0 0 0.05 0 0 0 0.02
4 5.83 11.44 8.83 7.37 8.89 43.67 0 0.05 35.05 0 0.02 0.01 15.92
5 13.66 15.62 14.74 17.93 22.66 81.52 3.19 7.92 70.78 2.9 3.6 3.25 34.9
6 14.74 15.95 15.34 19.47 27.5 133.96 4.12 12.15 118.83 3.75 5.52 4.84 53.92
7 16.39 16.81 16.61 21.56 31.46 153.45 4.95 14.85 136.64 4.5 6.75 5.82 62.2
8 17.93 17.49 17.71 24.2 35.66 167.88 6.49 18 150.15 5.9 8.25 7.07 68.25
11 18.15 19.03 18.59 28.6 44 186.78 10.01 15 168.18 9.1 11.56 10.32 76.45
12 18.15 19.8 18.97 30.36 42.74 193.34 11.38 25.41 174.4 10.35 13.07 11.71 79.27
14 18.37 20.02 19.19 32.56 52.14 200.75 13.38 28.78 181.55 12.15 14.97 13.56 82.52
15 18.58 20.13 19.36 34.32 55.33 205.15 14.96 32.94 185.79 13.6 16.35 14.97 84.75
18 18.58 20.57 19.56 37.16 59.07 214.83 17.6 35.97 195.25 16 18.2 17.1 88.75
20 19.25 21.01 20.13 39.27 63.14 220.33 19.14 40.04 200.2 17.4 19.55 18.47 91
22 20.66 21.01 20.84 42.48 65.47 222.42 21.61 43.01 201.52 18.85 20.32 20.01 91.42
25 21.56 21.01 21.28 45.87 66.42 222.42 24.58 44.82 201.13 22.35 21.42 21.89 91.42
27 22.66 21.01 21.83 47.65 66.63 223.96 26.01 47.13 202.12 23.85 21.72 22.69 91.87
28 22.99 21.01 22 54.34 74.25 225.3 32.34 47.79 203.5 29.4 23.75 26.57 92.5

Table 2: Theoretical CO2 %

  Stepantex X 1240
Flask FB 9
10 mg/L
FB 10
20 mg/L
Days - -
4 0.0% 0.0%
7 4.5% 6.7%
14 12.1% 15.0%
22 19.6% 20.4%
28 29.4% 23.7%
Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
Under the conditions and duration of the test the product Stepantex X 1240 shows a low degradation.
Executive summary:

Objective of the study

Determine under defined conditions, the biodegradability of an organic product in a mineral liquid medium inoculates a microbial flora of wastewater.

The biodegradability is experimee in% of theoretical CO2 produced.

Method of the study:

OECD Guideline for the Testing of Chemicals: Ready Biodegradability - Method 301B (17 July 1992): CO2 evolution test (modified Sturm).

Substances tested:

Agent 2076 -43D

Agent X 2197 -7 -7

Stepantex X 1040/2

Stepantex X 1040/1

Stepantex X 1240

Concentrations used:

10 and 20 mg / l organic carbon (initial, nominal)

Reference substance:

Aniline; 20 mg/l organic carbon

Inoculum:

Prepared from a sample of activated sludge from an urban wastewater treatment plant.

Duration of the study:

28 days

Results of the tests

The biodegradability of the five substances is evaluated at the end of the test (28 days):

As a percentage of theoretical CO2:

Concentration Agent 2076-43D Agent X 2197-7-7 Stepantex X 1040/2 Stepantex X 1040/1 Stepantex X 1240 Aniline
(ref.)
10 mg/L 50% 37% 70% 74% 29% -
20mg/L 53% 43% 69% 77% 24% 93%
Average 51% 40% 70% 75% 27% -

As percentage of TOC removal:

Concentration Agent 2076-43D Agent X 2197-7-7 Stepantex X 1040/2 Stepantex X 1040/1 Stepantex X 1240 Aniline
(ref.)
10 mg/L 77% 60% 84% 80% 49% -
20mg/L 72% 66% 92% 90% 44% 98%
Average 75% 63% 88% 85% 47% -

Conclusion:

Under the conditions and the test period, only the two ST and SP substances meet the criteria for ready biodegradability.

Description of key information

Under the conditions and duration of the test the product Stepantex X 1240 shows a low degradation.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:
freshwater

Additional information