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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From Jan. 24, 1992 to Apr. 29, 1992
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units)
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
no
Radiolabelling:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on source and properties of surface water:
Not applicable
Details on source and properties of sediment:
Not applicable
Details on inoculum:
- Source of inoculum/activated sludge: Activated sludge freshly collected from the aeration tank of Hofstade Sewage Treatment Plant, Zemst, Belgium. This STP receives primarily domestic wastewater.
- Storage length: Fresh sludge was used in the study
- Preparation of inoculum for exposure: Not reported
- Pretreatment: Not reported
- Concentration of sludge: Adjusted to approx. 2.5 g/L after collection
- Initial cell/biomass concentration: Not reported
Duration of test (contact time):
67 d
Initial conc.:
10.5 other: mg/L (Running-in period)
Based on:
DOC
Initial conc.:
20 other: mg/L (Evaluation period-Phase I)
Based on:
DOC
Initial conc.:
0 other: mg/L (Evaluation period-Phase II)
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Volume of test solution/treatment: Not reported
- Composition of medium: The CAS influent consisted of test substance, tap water, and nutrient media (synthetic sewage). The nutrient media included peptone, beef extract, urea, and K2HPO4.
- Additional substrate: None
- Solubilising agent (type and concentration if used): Not used
- Test temperature: Temperature of mixed liquor during running-in and evaluation period was 17-19°C and 18.5-20.5°C respectively (measured each working day)
- pH: Ranged from 5.8-7.4 in both the test and control units. (measured twice a week by pH meter)
- Ammonia level: Ammonia levels were 0.4-11.2 mg/L (Test unit) and 0.4-10.2 mg/L (Control unit)
- Aeration of dilution water: Not reported
- Suspended solids concentration: TSS values were 1.16 to 2.51 g/L (Test unit) and 1.07-2.26 (Control unit. The TSS levels were determined twice weekly on a representative 100 mL aliquot of the wasted sludge by filtration through a Watman GF/A glass fiber filter and subsequent drying at 105°C for 24 h.
- Continuous darkness: Not reported
- Any indication of the test material adsorbing to the walls of the test apparatus: Not reported
- Other:
- HRT (Hydraulic Retention Time): 6 h.
- Influent flow rate: 480-520 mL/h. A new batch of influent (tap water, test substance and nutrient) was made every two days by dilution of the concentrated test and nutrient stock solution in the effluent collected during two days.

TEST SYSTEM
- Culturing apparatus: 2 CAS (Continuously Activated Sludge) units were used for this test-
Unit 1: Test unit
Unit 2: Control unit.
- Number of culture flasks/concentration: Single CAS unit (both for test and control)
- Method used to create aerobic conditions: Not reported
- Measuring equipment: DOC was measured by Dohrmann Carbon Analyzer.
- Test performed in open system: Not reported

SAMPLING
- Sampling frequency: On Day 1, 4-7, 11-15, 18-22, 25-29, 32-36, 39-43, 46-50, 53, 54, 56, 57, 60-62, 67 and 68
- Sampling method: Not reported
- Sample storage before analysis: Samples were analyzed within 2 h after collection

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: No
- Toxicity control: No

STATISTICAL METHODS: Not reported
Reference substance:
not required
Test performance:
No data
Compartment:
other: water / sediment, material (mass) balance
Remarks on result:
other: not reported
% Degr.:
97
St. dev.:
2
Parameter:
DOC removal
Sampling time:
27 d
Remarks on result:
other: Running-in period
% Degr.:
101.8
St. dev.:
1.1
Parameter:
DOC removal
Sampling time:
45 d
Remarks on result:
other: Evaluation period-Phase I
% Degr.:
101.9
St. dev.:
0.4
Parameter:
DOC removal
Sampling time:
67 d
Remarks on result:
other: Evaluation period-Phase II
Transformation products:
not measured
Details on results:
- DOC removal of the test substance was 94.4-100.2 (running-in period), 91.4-103.6 (Evaluation period-Phase I) and 101.5-102.3 (Evaluation period-Phase II). For details please refer to ‘Table 1’ under ‘Any other information on results incl. tables’
- The dissolved oxygen was > 5 mg/L during the entire test period.
Results with reference substance:
Not applicable

Table 1. Metabolite test of Alkyl sulphate (study # 35882)

Day

DOC removal (%)

Running in period

1

99

4

96

5

99.2

6

99.3

7

96.5

11

100.2

12

96

14

98

15

100.2

18

95.3

19

94.4

20

96.8

21

97

22

98.9

25

94.4

26

98.6

Evaluation period

Phase I

27

91.4

28

98.8

29

99.1

32

102

33

100.9

34

101.2

35

100.5

36

102.8

39

101.3

40

100.5

41

100.8

42

101.5

43

101.6

46

100.4

47

101.7

48

103.3

49

102.1

50

101.2

53

101.7

54

103.6

Phase II

56

102.3

57

102.3

60

102.3

61

101.6

62

101.7

67

101.5

68

101.6

Validity criteria fulfilled:
yes
Conclusions:
C12-14 Alkyl Sulphate underwent complete biodegradation in Continuous Activated Sludge (CAS) units. At Day 67, the % biodegradation was 101.9 and there was no indication of the presence of any biodegradation residues or non-biodegradable minor components.
Executive summary:

The biodegradation of C12-14 Alkyl Sulphate was evaluated in a Continuous Activated Sludge (CAS) test, conducted under aerobic conditions in accordance with the OECD 303A guideline, following the OECD Coupled Units method. The test was run in three periods: running-in period (42 days; dosed with 10.5 mg/L as DOC after the first week); phase I (30 days, dosed with 20 mg/L as DOC); and phase II (12 days; no test substance added). The inoculum was activated sludge from a municipal wastewater treatment plant receiving predominantly domestic waste.

The biodegradation of alkyl sulphate at the end of each phase was:

         Running-in period: 97%

         Evaluation period (Phase I): 101.8%

         Evaluation period (Phase II): 101.9%

Hence, C12-14 Alkyl Sulphate was completely removed and there was no indication of the presence of any biodegradation residues or non-biodegradable minor components.

This metabolite test satisfied the guideline requirements for the OECD 303 A simulation tests to assess the primary and/or ultimate biodegradation of chemicals discharged in wastewater

Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
From March 10, 1994 to July 18, 1994
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, followed guideline, GLP
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study
Qualifier:
equivalent or similar to guideline
Guideline:
other: OECD 314D. Deviations, reliability, and validity evaluated against current OECD 314D (Oct. 3, 2008)
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes
Remarks:
EPA GLP
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable
Radiolabelling:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
other: Mixture of Surface water, sewage effluent and activated sludge
Details on source and properties of surface water:
- Details on collection: The river water was collected from the Lower East Fork of the Little Miami River (Milford, OH) above the outfall of the Lower East Fork Sewage Treatment Plant (STP). The sample was collected on April 4, 1994
- Storage conditions: The water was aerated until use
- Storage length: Not specified
Details on source and properties of sediment:
Not applicable
Details on inoculum:
- Source of inoculum/activated sludge: The effluent was collected from the lower East Fork STP (Milford Ohio), and the activated sludge was collected from Sycamore Sewage Treatment Plant (Cincinnati, OH). The samples were collected on April 4, 1994
Duration of test (contact time):
31 d
Initial conc.:
75 µg/L
Based on:
act. ingr.
Parameter followed for biodegradation estimation:
CO2 evolution
test mat. analysis
other: biomass... (see attached file)
Details on study design:
TEST CONDITIONS
- Volume of test solution/treatment: 560 µL dosing solution was used for each flask
- Additional substrate: None
- Solubilising agent: Not used
- Test temperature: The test bottles were incubated at 22°C and gently mixed on shaker table.
- pH: The pH of biotic and abiotic flasks was 8.2 prior to dosing the test material
- Aeration of dilution water: Not reported
- Continuous darkness: Not reported

TEST SYSTEM
- Culturing apparatus: 2 L Erlenmeyer flask consisted of 1.4 L of a river water mixture (89% river water, 10% sewage effluent, 1% activated sludge supernatant) and 560 µL dosing solution
- Number of culture flasks/concentration: Two
- Method used to create aerobic conditions: The headspace of the test flasks were continuously purged with CO2 free air.
- Measuring equipment: Carbon dioxide measuring apparatus consisted of: (a) CO2 scrubber: i) Ascarite trap and ii) Three methyl red indicating traps to serve as a CO2 indicator trap. These traps connected in series with to a pressurized air source (b) CO2 production apparatus: 2 L Erlenmeyer flasks connected by tubing to the CO2-free air source; (c) Three CO2 absorber bottles: Absorber bottles filled with 1.5 N KOH
- Test performed in closed vessels: Yes
- Test performed in open system: No
- Details of trap for CO2 and volatile organics if used: Bottles containing 1.5 N KOH were used as base traps for CO2
- Other: To terminate the experiment, the test flasks were acidified with 5mL of concentrated HCI, injected through a sampling port. The flasks were purged with CO2 free air for several days and the base traps were sampled a final time.

SAMPLING
- Sampling frequency: At 1, 15, 30 min and 1, 2, 4, 5, 6, 9.25, 13.25, 17.25, 22.5, 30 h, and on Days 2, 3, 6, 7, 8, 10, 14, 21, 28, and 31 (after acidification).
- Sampling method: At each sampling time, the following samples were collected:
For analysis of Evolved 14CO2: The first KOH trap in the series was opened and sampled. Triplicate 1 mL aliquots were removed and mixed with 15 mL Ultima Gold scintillation cocktail. This trap was reconnected or removed, in which case the traps were moved forward and a fresh trap added behind the existing traps.

For analysis of Dissolved CO2: A 7 mL sample was removed and the pH adjusted to approx. 10 with 200 µL of 1.5 N KOH. Six 1mL aliquots were placed in separate microcentrifuge tubes, three of these samples were centrifuged and the supernatant was collected for further analysis. The remaining three tubes were centrifuged, the supernatant was transferred to scintillation vials and acidified with 250 µL of 10% HCI.

For analysis of parent compound, metabolite and radioactivity associated with solids: 15 mL sample was removed from each test flask and immediately flash frozen in a dry ice-acetone bath.
- Sample storage before analysis: Not specified

CONTROL AND BLANK SYSTEM
- Inoculum blank: No
- Abiotic sterile control: Yes (River water was autoclaved and amended with mercuric chloride (1g/L) to serve as an abiotic control)
- Toxicity control: No

STATISTICAL METHODS:
The loss of parent (%) data were fitted to various decay equations and the mineralization (%CO2) and complete biodegradation (% CO2 +% biomass) data were fitted to production equations using nonlinear regression. Regression analysis was performed using Jandel Table Curve 2D (version 2.00) software. The equation that provided the best fit were identified based upon statistical considerations (r2 and number of parameters estimates) and visual inspection of the fit and residuals
Reference substance:
not required
Test performance:
No data
Compartment:
other: water, material (mass) balance
% Recovery:
97.4
St. dev.:
3.2
% Degr.:
52.9
Parameter:
CO2 evolution
Remarks:
(Mineralization)
Sampling time:
22.5 h
% Degr.:
39.5
Parameter:
other: % of radioactivity associated with solids
Sampling time:
22.5 h
% Degr.:
0
Parameter:
other: % of radioactivity as parent and metabolite
Sampling time:
22.5 h
Compartment:
water
DT50:
0.22 h
Type:
other: First order
Remarks on result:
other: Half-life of primary biodegradation
Other kinetic parameters:
first order rate constant
other: 3/2 order rate constant without growth (provided the best statistical fit) 2.12±0.27 h-1 for ultimate biodegradation ... (see attached file)
Transformation products:
yes
No.:
#1
No.:
#2
Details on transformation products:
See ‘Details on results’ below.
Evaporation of parent compound:
no
Volatile metabolites:
no
Residues:
yes
Details on results:
TEST CONDITIONS
- Aerobicity, moisture, temperature and other experimental conditions maintained throughout the study: Yes

MAJOR TRANSFORMATION PRODUCTS: Fatty alcohol, fatty acid

MINOR TRANSFORMATION PRODUCTS: Not determined in the study

TOTAL UNIDENTIFIED RADIOACTIVITY (RANGE) OF APPLIED AMOUNT: Not reported

EXTRACTABLE RESIDUES: TLC analysis revealed the presence of a single peak at Rf 0.54, which corresponded to the parent alkyl sulfate). The disappearance of parent from the bioactive treatment was rapid, and no parent was detected after 4h. This loss of parent was associated with thepresence of two new peaks, at Rf 0.86 and 0.98 which co-chromatographed with authentic fatty alcohol and fatty acid standards. Fatty alcohol was the most prominent intermediate reaching a maximum level of 22 % after 30 min. Fatty acid was at a maximum level of 12% after 13 h. Both intermediates completely disappeared by 22 h.
- % of applied amount at Day 0: 93.4% in active flask (parent; sample time was 0.08 h)

- % of applied amount at end of study period: 0% in active flask (parent; sample time was 144 h)

NON-EXTRACTABLE RESIDUES: Incorporation into biomass was very rapid and reached a maximum of 53% after 2 h and subsequently plateaued at approx. 25% for the remainder of the study.
- % of applied amount at Day 0: 6.6 % in active flask (sample time was 0.08 h)

- % of applied amount at end of study period: 30.7 % in active flask (sample time was 144h)

MINERALISATION: The evolution of 14CO2 was rapid and reached 25% after 1h, 50% after 30 h, and 75% after 14 d.
- % of applied radioactivity present as CO2 at end of study: 65.8% in bioactive test flask (sample time was 144 h). CO2 evolution was not analyzed for abiotic flask as radioactivity in the abiotic control was recovered primarily as intact parent. For details, please refer to ‘table 1’ in the ‘Any other information on results incl. tables’ section.

VOLATILIZATION
- % of the applied radioactivity present as volatile organics at end of study: No volatilization of test material was observed as the TLC analysis of the abiotic control revealed that the parent test material remained intact throughout the experiment.


Results with reference substance:
Not applicable

Mineralization test of Alkyl sulfate (study # 35563)

Table 1: Bioactive flask

Time (h)

%Parent

%CO2

%Metabolites

Total % biomass

* Total biodegradation

Mass balance

0.08

93.4

NA

0

6.6

NA

100

0.25

59.4

9.7

10.6

20.3

30

100

0.5

45.9

7

25

22.2

29.2

100.1

1

14.1

25.1

18

42.9

67.9

100.1

4

0

33

18.5

48.9

81.9

100.4

6

0

34.7

17

48.5

83.2

100.2

13.25

0

42.6

14.2

43.2

85.8

100

22.5

0

52.9

0

39.5

92.4

92.4

30

0

51

0

36

87

87

48

0

63.8

0

31

94.8

94.8

72.5

0

61.1

0

35.9

97

97

144

0

65.8

0

30.7

96.4

96.5

Mean

97.4±3.2

Abiotic control (mean± S.D)

89.7±7.7

NA

3.6±3.6

5.8 ± 1.1

NA

* CO2 +incorporation into biomass

Table 2: Abiotic flask

Sample Time (h)

% Parent

%CO2

% Metabolite

Total % biomass

Mass balance

0.25

90.1

NA

3.3

6.6

100

4

94.1

NA

0

6

100.1

22.5

83.3

NA

9.7

7

100

Mean

100.03±0.04

Validity criteria fulfilled:
yes
Conclusions:
Alkyl sulfate was completely removed from surface water. After 23 h, 53% was mineralized, 40% was non-extractable (solids), and 0% remained as either parent compound or metabolite. The rate constants for primary biodegradation, ultimate biodegradation, and mineralization in surface water were 3.17, 2.12, and 0.34 h-1, respectively.
Executive summary:

A simulation of the biodegradation of Alkyl sulfate in surface water (89% river water, 10% sewage effluent and 1% activated sludge supernatant) was conducted under aerobic conditions in accordance with the OECD 314D guideline. A solution of radiolabeled tetradecyl alkyl sulfate was tested at 75 µg/L. The inoculum was river water, supplemented with a small portion of effluent and activated sludge ( 89% river water, 10% sewage effluent, 1% activated sludge supernatant). The river water was obtained from the East Fork of the Little Miami River above the outfall of the Lower East Fork Sewage Treatment Plant (STP), which was the source of the effluent. Activated sludge was collected from the Sycamore Sewage Treatment Plant. The test treatments were measured in duplicate.

After 23 h, 53% was mineralized, 40% was non-extractable (solids), and 0% remained as parent or metabolite. 

The rate constants for biodegradation of alkyl sulfate in surface water were:

Primary biodegradation: 3.17 h-1

Ultimate biodegradation: 2.12 h-1Mineralization: 0.34 h-1

This biodegradation simulation test satisfied the guideline requirements for the OECD 314 D simulation tests to assess the biodegradability of chemicals discharged in wastewater.

Endpoint:
biodegradation in water: sediment simulation testing
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance is readily biodegradable
Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
From May 15, 1995 to July 14, 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Reason / purpose for cross-reference:
reference to same study
Qualifier:
according to guideline
Guideline:
other: OECD 314B. Deviations, reliability, and validity evaluated against current OECD 314B (Oct. 3, 2008)
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
no
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable
Radiolabelling:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on source and properties of surface water:
Not applicable
Details on source and properties of sediment:
Not applicable
Details on inoculum:
- Source of inoculum/activated sludge: Two sources of activated sludge were used in the study for two experiments:
Experiment 1: Polk Run Sewage Treatment Plant (STP) (sludge collection date: May 15, 1995)
Experiment 2. Sycamore Sewage Treatment Plant (STP) (sludge collection date: June 25, 1995).
Both STPs receive predominantly domestic waste. Both STPs are located in the greater Cincinnati, Ohio area. 
- Storage conditions: Activated sludge was aerated until use.
- Storage length: Not reported
- Preparation of inoculum for exposure: Not reported
- Pretreatment: None
- Concentration of sludge: 2500±300 mg/L
- Initial cell/biomass concentration: Not reported
- Note: The study report references a study protocol and several P&G testing standards.
Duration of test (contact time):
24 h
Initial conc.:
1 mg/L
Based on:
act. ingr.
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
TEST CONDITIONS
- Volume of test solution/treatment: 500 mL
- Composition of medium: Each 500m L test flask contained:
500 mL activated sludge
Dosing solution 1.3 mL (experiment 1) and 0.55 mL (experiment 2)
- Test temperature: Room temperature
- pH: The pH of flasks prior to dosing solution were as follows:
Experiment 1:The pH of biotic and abiotic flasks was 6.8 and 6.5 respectively
Experiment 2: The pH of biotic and abiotic flasks was 6.5 prior to dosing the test material.
- Aeration of dilution water: Not reported
- Suspended solids concentration: Not reported
- Continuous darkness: Not reported
- Other: The test flasks were gently stirred continuously at a speed fast enough to keep solids well mixed.

TEST SYSTEM
- Culturing apparatus: 2 L Erlenmeyer flask consisted of 500 mL of fresh or abiotic activated sludge with dosing solution 1.3 mL (experiment 1) and 0.55 mL (experiment 2)
- Number of culture flasks/concentration: Two (both for biotic and abiotic flasks)
- Method used to create aerobic conditions: Not reported
- Measuring equipment: CO2 measuring apparatus is not reported in the study and mineralization to 14CO2 was determined indirectly by measuring the difference in total radioactivity between samples from the biotic and abiotic treatments.
- Details of trap for CO2 and volatile organics if used: Not reported
- Other: Erlenmeyer flasks were pretreated with a 5 mg/L solution of unlabeled test material prior to the experiment to reduce sorption to glassware

SAMPLING
- Sampling frequency: At 1, 10, 15, 30, 45 min and 1, 1.5, 2, 4, 6, 8.5 and 24 h (for both experiments 1&2)
- Sampling method: At each sampling time, the following samples were collected:
For analysis of mineralization: Triplicate 1 mL mixed liquor suspended solids samples (MLSS) were removed from each test flask and acidified with 1 mL of 0.5% HCL and allowed to sit overnight.
For analysis of parent compound and radioactivity associated with solids: 10 mL sample was removed from each test flask and immediately flash frozen in a dry ice-acetone bath. These frozen samples were then lyophilized on a Virtis Benchtop Freeze Dryer.
- Sample storage before analysis: Not specified.

CONTROL AND BLANK SYSTEM
- Inoculum blank: No
- Abiotic sterile control: Yes (Sludge was autoclaved and amended with mercuric chloride (1g/L) to serve as an abiotic control)
- Toxicity control: No

STATISTICAL METHODS: The loss of parent (%) data was fitted to various decay equations, and the mineralization (%CO2) and complete biodegradation (%CO2+% Biomass) data were fitted to various production equations using nonlinear regression. Regression analyses were performed using Jandel Table Curve 2D (version 2.00) software.
Reference substance:
not required
Test performance:
No data
Compartment:
other: water, material (mass) balance
% Recovery:
86.6
St. dev.:
5.3
% Degr.:
69
Parameter:
CO2 evolution
Remarks:
(mineralization)
Sampling time:
24 h
Remarks on result:
other: Normalized to 100% mass balance. (inoculum source: Polk run STP)
% Degr.:
1.5
Parameter:
other: % of radioactivity as parent
Sampling time:
24 h
Remarks on result:
other: Normalized to 100% mass balance. (inoculum source: Polk run STP)
% Degr.:
9.7
Parameter:
other: % of radioactivity as metabolite
Sampling time:
24 h
Remarks on result:
other: Normalized to 100% mass balance. (inoculum source: Polk run STP)
% Degr.:
19.8
Parameter:
other: % of radioactivity associated with solids
Sampling time:
24 h
Remarks on result:
other: Normalized to 100% mass balance. (inoculum source: Polk run STP)
% Degr.:
66
Parameter:
CO2 evolution
Remarks:
(mineralization)
Sampling time:
24 h
Remarks on result:
other: Normalized to 100% mass balance. (inoculum source: Sycamore STP)
% Degr.:
2
Parameter:
other: % of radioactivity as parent
Sampling time:
24 h
Remarks on result:
other: Normalized to 100% mass balance. (inoculum source: Sycamore STP)
% Degr.:
6
Parameter:
other: % of radioactivity as metabolite
Sampling time:
24 h
Remarks on result:
other: Normalized to 100% mass balance. (inoculum source: Sycamore STP)
% Degr.:
26
Parameter:
other: % of radioactivity associated with solids
Sampling time:
24 h
Remarks on result:
other: Normalized to 100% mass balance. (inoculum source: Sycamore STP)
Other kinetic parameters:
other: 3/2 order rate constant without growth (provided the best statistical fit) 73.9±5.0 h-1 for primary degradation (inoculum source: Polk run STP)... (see attached file)
Transformation products:
yes
No.:
#1
No.:
#2
Details on transformation products:
See "details on results" below.
Evaporation of parent compound:
no
Volatile metabolites:
not measured
Residues:
yes
Details on results:
TEST CONDITIONS
- Aerobicity, moisture, temperature and other experimental conditions maintained throughout the study: Yes

MAJOR TRANSFORMATION PRODUCTS: Fatty alcohols, fatty acids (see description of Extractable Residues below).

MINOR TRANSFORMATION PRODUCTS: Not determined in the study

TOTAL UNIDENTIFIED RADIOACTIVITY (RANGE) OF APPLIED AMOUNT: Not reported

EXTRACTABLE RESIDUES:

Experiment 1: All samples from the abiotic control exhibited a single peak at Rf 0.33, which corresponded to the parent sodium tetradecyl sulfate. This peak was also observed in the biologically active treatment. The most prominent peaks that appeared in the biologically active treatment were at Rf 0.84 and Rf 0.94, and corresponded to fatty alcohol and fatty acid standards, respectively. A single unidentified polar peak was briefly observed at Rf 0.06, and another unidentified peak was observed at Rf 0.44, which accounted for no more than 9% of the initial radioactivity. The most prominent metabolite corresponded to fatty acid, which reached a maximum of20% after 30 minutes. A peak corresponding to fatty alcohol was highest at the first sampling (8%).

Experiment 2: All samples from the abiotic control exhibited a single peak at Rf 0.04, which corresponded to the parent test sodium tetradecyl sulfate. This peak was also observed in the biologically active treatment. The most prominent peaks that appeared in the biologically active treatment were at Rf 0.90 and Rf 0.95, and co-chromatographed with fatty alcohol and fatty acid standards, respectively. A single unidentified polar peak was briefly observed at Rf 0.05, and another unidentified peak was observed at Rf 0.5, which accounted for less than 5% of the initial radioactivity. The most prominent metabolite corresponded to fatty acid, which reached a maximum of 37% after 10 minutes. A peak corresponding to fatty alcohol was highest, also at the 10 minute sampling (20%)

- % of applied amount at Day 0: 30.78 % (experiment 1) and 40.9% (experiment 2)in active flask (parent; sample time was 0.017 h)
- % of applied amount at end of study period: 1.35% (experiment 1) and 1.5% (experiment 2) in active flask (parent; sample time was 24h)

NON-EXTRACTABLE RESIDUES:

Experiment 1: Incorporation into biomass began immediately, and was reached its maximum level after 10 min (24%). After 24 h, it had decreased to 17%. The majority of the radioactivity was incorporated into proteins, nucleic acids, and cell wall fractions.

Experiment 2: Incorporation into biomass began quickly, and reached its maximum level after 2 h (30%). After 24 h, it had decreased to 20%. The majority of the radioactivity was incorporated into proteins, nucleic acids, and cell wall fractions.
- % of applied amount at Day 0: 13.10% (experiment 1) and 7.5% (experiment 2) in active flask (sample time was 0.017 h)
- % of applied amount at end of study period: 17.17% (experiment 1) and 20.5% (experiment 2) in active flask (sample time was 24 h)

MINERALISATION
- % of applied radioactivity present as CO2 at end of study: 60% (experiment 1) and 52% (experiment 2) in bioactive test flask (sample time was 24 h). CO2 evolution was not analyzed for abiotic flask as radioactivity in the abiotic control was recovered primarily as intact parent. For details, please refer to ‘table 1’, ‘table2’, ‘table3’ and ‘table 4’ in the ‘Any other information on results incl. tables’ section.

VOLATILIZATION: No volatilization of test material was observed as the TLC analysis of the abiotic control revealed that the parent test material remained intact in both the experiments (experiment 1 and experiment 2)

OTHERS: The rate constants were also calculated by other models in both experiments (1&2) such as 3/2 Order without growth and First order. The details can be found in the study report.
Results with reference substance:
Not applicable

Experiment 1: Aerobic die-away of Tetradecyl sulfate in activated sludge from Polk run sewage treatment plant (Study # 35966)

Table 1: Biotic flask

Time (h)

% Parent

% CO2

% Metabolites

Total % Biomass

* Total Biodegradation

Mass balance

0.017

30.78

NA

26.35

13.1

13.1

70.23

0.08

10.34

26.2

36.37

24.12

50.31

97.03

0.25

3.99

31.24

25.63

23.15

54.4

84.01

0.5

2.94

34.56

34.99

13.79

48.34

86.28

0.75

3.02

37.37

22.72

21.1

58.48

84.21

1

2.55

41.09

21.45

21.78

62.87

86.87

1.5

2

42.62

22.44

19.61

62.23

86.67

2

2.36

44.17

12.74

17.24

61.41

76.51

4

1.75

48.08

21.76

21.34

69.42

92.93

6

1.69

50.33

16.6

21.48

71.81

90.1

8.5

2.41

52.1

19.57

23.57

75.66

97.65

24

1.35

59.84

8.43

17.17

77.01

86.79

Mean

86.6±5.3

Abiotic Control Mean±S.D.

89.66±10.63

NA

Not Detected

2.16±1.43

NA

* CO2 +incorporation into biomass

Table 2: Abiotic flask

Sample Time (h)

% Parent

%CO2

% Metabolite

Total % biomass

Mass balance

0.25

93.1

NA

0

0.9

94

8.5

85.3

NA

0

3.1

88.4

24

98.7

NA

0

0.7

99.4

Mean

94±3.7

Experiment 2: Aerobic die-away of Tetradecyl sulfate in activated sludge from Sycamore sewage treatment plant (Study # 35966)

Table 3: Biotic flask

Time (h)

% Parent

% CO2

% Metabolites

Total % Biomass

* Total Biodegradation

Mass balance

0.017

40.9

NA

26.8

7.5

7.5

75.2

0.08

14.2

11.7

58.9

7.2

18.9

92

0.25

5.2

21.8

26.35

23.2

45

76.55

0.5

3

29.8

25.3

24.2

54

82.3

0.75

1.4

32.3

24.1

28.8

61.1

86.6

1

1.8

33.7

25.1

20.1

53.8

80.7

1.5

0

36.5

27.3

18.3

54.9

82.1

2

1.9

38.1

13.1

29.5

67.6

82.6

4

2.4

42.2

11.9

26.1

68.3

82.6

6

2.3

51.2

10.5

26.6

77.8

90.6

8.5

2.5

45.6

11.6

28.4

74

88.1

24

1.5

52

4.9

20.5

72.4

78.9

Mean

83.18±4.01

Abiotic Control Mean±S.D.

69.5 ±11.9

NA

Not Detected

1.0±0.8

NA

Table 4: Abiotic flask

Sample Time (h)

% Parent

%CO2

% Metabolite

Total % biomass

Mass balance

0.5

66.5

NA

0

2

68.5

8.5

68.4

NA

0

1.6

70

24

81.5

NA

0

0.2

81.7

Mean

 

 

 

 

73.4±5.53

Validity criteria fulfilled:
yes
Conclusions:
The removal of sodium tetradecyl sulfate was 98-98.5% in two activated sludge die-away tests (24 hours). The tetradecyl sulfate was mineralized (66-69%), incorporated into solids (20-26%), transformed into a metabolite (6-10%), or remained as parent (1.5-2%), after 24 hours. (See Executive Summary for rate constants.)
Executive summary:

The biodegradation of Sodium tetradecyl sulfate (C14AS) was evaluated in two activated sludge die-away studies, conducted under aerobic conditions in accordance with the OECD 314B guideline. A solution of radiolabeled Sodium tetradecyl sulfate was tested at 1 mg/L. The activated sludge die-away tests used inoculum collected from either the Polk Run or the Sycamore sewage treatment plants. These municipal wastewater treatment plants receive predominantly domestic waste. Each test treatment was measured in duplicate.

Experiment 1 (Polk Run STP activated sludge): 

98.5% of C14AS was removed (24 hrs). After 24 h, 69% was mineralized, 19.8% was non-extractable (solids), 9.7% was metabolite, and 1. 5% remained as parent. The rate constants for biodegradation of Sodium tetradecyl sulfate in Polk Run activated sludge were:

Primary biodegradation: 74 h-1

Complete biodegradation: 20.5 h-1

Mineralization: 10 h-1

Experiment 2 (Sycamore STP activated sludge):

98.0% of C14AS was removed (24 hrs). After 24 h, 66% was mineralized, 26% was non-extractable (solids), 6% was metabolite, and 2% remained as parent. The rate constants for biodegradation of Sodium tetradecyl sulfate in Sycamore activated sludge were:

Primary biodegradation: 53.5 h-1

Complete biodegradation: 3.6 h-1

Mineralization: 3.4 h-1

This biodegradation simulation test satisfied the guideline requirements for the OECD 314 B simulation tests to assess the biodegradability of chemicals discharged in wastewater.

Endpoint:
biodegradation in water: simulation testing on ultimate degradation in surface water
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance is readily biodegradable
Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Reason / purpose for cross-reference:
read-across source
% Degr.:
97
St. dev.:
2
Parameter:
DOC removal
Sampling time:
27 d
Remarks on result:
other: Running-in period
Remarks:
Source, key, 85586-07-8, 1992
% Degr.:
101.8
St. dev.:
1.1
Parameter:
DOC removal
Sampling time:
45 d
Remarks on result:
other: Evaluatio period-Phase I
Remarks:
Source, key, 85586-07-8, 1992
% Degr.:
101.9
St. dev.:
0.4
Parameter:
DOC removal
Sampling time:
67 d
Remarks on result:
other: Evaluation period-Phase II
Remarks:
Source, key, 85586-07-8, 1992
Transformation products:
not measured

Description of key information

Biodegradation of 100% after 67 days based on DOC removal (OECD 303A)

Key value for chemical safety assessment

Additional information

In accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5, read-across to other structurally related category members was conducted. Read-across data for similar substances, C12-14AS Na (CAS 85886-07-8) and C14AS Na (1191-50-0) was used.

The key simulation biodegradation test with C12-14AS Na (CAS 85886-07-8) was conducted according to OECD 303 A by Potoms (1992). It was demonstrated that approximately 100% of the DOC were eliminated using domestic non-adapted activated sludge after 67 days. There was no indication of the presence of any biodegradation residues or non-biodegradable minor components.

Two supporting studies performed according OECD guideline 314 B and 314 D (Federle 1996a, Federle 1996 b, respectively) are available for C14AS Na (1191-50-0). The OECD 314 B test showed that the removal of C14AS Na (CAS 1191-50-0) was around 98.5% in two activated sludge die-away tests (24 hours). The substance was mineralized (66-69%), incorporated into solids (20-26%), transformed into a metabolite (6-10%), or remained as parent (1.5-2%), after 24 hours. The OECD 314 D test revealed that the substance was completely removed from surface water. After 23 hours 53% was mineralized, 40% was non-extractable (solids), and no substance remained as either parent compound or metabolite. The rate constants for primary biodegradation, ultimate biodegradation, and mineralization in surface water were 3.17, 2.12, and 0.34 h-1, respectively.