Fatty acids, tall-oil, compds. with triethanolamine

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991 - 1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Read accross justification is attached in section 13

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1996

Materials and methods

Test guideline

Guideline:

other: Not specified

Principles of method if other than guideline:

Biodegradation of TEA was examined in a series of reaction mixtures containing combinations of 4.0 or 38.2 µmol/L (600 or 5,700 µg/L) TEA and 164 or 818 mg/L Mixed Liquor Suspended Solids (MLSS) in a minimal salts basal medium. Duplicate reactions containing each combination of test material and mixed liquor solids concentrations were prepared in 500 mL polypropylene Erlenmeyer flasks.
Single biologically inhibited control reactions were prepared for each configuration to measure potential abiotic losses of TEA. These were prepared in a manner similar to the viable reactions, with the exception that formaldehyde was incorporated at a final concentration of 2.8% (w/v). All reactions were amended with [U-14C]TEA to yield approximately 0.7 µCi/ml reaction solution. The specific activity of the [U-14C]TEA was adjusted with concentrated aqueous TEA solution to yield the desired total concentrations of test material.
The reaction flasks were sealed using rubber stoppers fitted with 16 x 150-mm glass tubular CO2 traps containing 4 mL of a 1 N KOH solution.
These traps consisted of capped culture tubes with openings cut near the bottom to allow headspace gas contact with the trap solution as the reaction mixtures were agitated. The activated sludge reactions were incubated in darkness at 25C, with agitation provided at 125 rpm on a gyratory shaker.
The distribution of [14C] radiolabel among TEA and its degradation products was determined using a strong cation-exchange HPLC (SCX- HPLC) separation coupled with flow-cell radiochemical detection.
The activated sludge experiments were designed to estimate the effect of varied initial TEA and biomass (as MLSS) concentrations on the rates of primary and ultimate biodegradation. The rate constants determined for primary biodegradation and mineralization indicate that both processes were generally first order in biomass (MLSS) and TEA concentrations over the range of concentrations studied. Mineralization closely followed primary biodegradation, with maximum yields of CO2 at experimental termination equivalent to between 52 and 56% conversions of the added organic carbon as TEA.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

2,2',2''-nitrilotriethanol

EC Number:

203-049-8

EC Name:

2,2',2''-nitrilotriethanol

Cas Number:

102-71-6

Molecular formula:

C6H15NO3

IUPAC Name:

2,2',2''-nitrilotriethanol

Test material form:

not specified

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No. of test material: Radiolabelled source from DuPont NEN Research Products. Nonradiolabelled source from Aldrich Chemical Company. Lot/batch not specified.
- Expiration date of the lot/batch: Not specified
- Purity test date: >99%

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: >98%
- Specific activity: 17.61 mCi/mmol
- Locations of the label: 14C
- Expiration date of radiochemical substance: Not stated

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Not specified
- Stability under test conditions: Not specified
- Solubility and stability of the test substance in the solvent/vehicle: Not specified
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: n/a

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Not specified
- Preliminary purification step (if any): Not specified
- Final dilution of a dissolved solid, stock liquid or gel: Not specified
- Final preparation of a solid: n/a

FORM AS APPLIED IN THE TEST (if different from that of starting material) n/a

TYPE OF BIOCIDE/PESTICIDE FORMULATION (if applicable) n/a

OTHER SPECIFICS: n/a

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks:

mixed liquor (secondary effluent)

Details on inoculum:

- Temperature (°C) at time of collection: Not specified- pH at time of collection: Not specified - Oxygen concentration (mg/l) initial/final:
- Dissolved organic carbon (%): not specified
- Source of activated sludge (e.g. location, contamination history): West Bay County Wastewater Treatment Plant, Bay City, Michigan. Facility represented a typical municipal activated sludge process treating a daily flow of between 3 and 4 million gallons of primarily municipal (>90% v/v) sewage. A consolidated mixed liquor sample was collected just prior to secondary clarification.
- Laboratory culture: Not specified
- Method of cultivation: Not specified
- Storage conditions: Not specified
- Storage length: Not specified
- Preparation for exposure: Not specified
- Pretreatment: The sample was aerated in the laboratory for approximately 22 hours to provide for removal of residual dissolved organic substrates. The mixed liquor was used in its collected state and diluted to achieve desired MLSS levels in the experimental reaction mixtures.
- Biomass concentration (mg/L) used in test: Not specified

Duration of test (contact time):

ca. 144 ca. h

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

ca. 600 µg/L

Based on:

test mat.

Remarks:

Lower concentration

Initial test substance concentration 2

Initial conc.:

ca. 5 700 µg/L

Based on:

test mat.

Remarks:

Upper concentration

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation 1

Parameter followed for biodegradation estimation:

CO2 evolution

Remarks:

14CO2 was trapped and quantified

Parameter followed for biodegradation estimation 2

Parameter followed for biodegradation estimation:

test mat. analysis

Remarks:

Ion exchange HPLC, with radiochemical detection.

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment: 600 µg/L (lower conc.) or 5700 µg/L (upper conc.), with 164 mg/L (lower) or 818 mg/L (upper) mixed liquor suspended solids (MLSS). All reactions were amended with [14C]TEA to yield approximately 0.7 µCi/ml reaction solution.
- Composition of medium: Minimal salts basal medium
- Additional substrate: Not specified
- Solubilising agent (type and concentration if used): Not specified
- Test temperature: 25ºC
- pH: Not specified
- pH adjusted: Not specified
- CEC (meq/100 g): Not specified
- Aeration of dilution water: Activated sludge was aerated for 22 hours
- Suspended solids concentration: 164 mg/L (lower) and 818 mg/L (upper)
- Continuous darkness: Yes
- Any indication of the test material adsorbing to the walls of the test apparatus: Not specified - Other: Continuous agitation was provided on a gyratory shaker at 125 rpm.

TEST SYSTEM
- Culturing apparatus: 00-ml polypropylene Erlenmeyer flasks.
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: The sample was aerated in the laboratory for approximately 22 hours to provide for removal of residual dissolved organic substrates.
- Method used to create anaerobic conditions: n/a
- Method used to control oxygen conditions: The reaction flasks were sealed using rubber stoppers
- Measuring equipment: Not specified
- Test performed in closed vessels due to significant volatility of test substance: Yes
- Test performed in open system: No
- Details of trap for CO2 and volatile organics if used: The reaction flasks were sealed using rubber stoppers fitted with 16 x 150-mm glass tubular CO2 traps containing 4 ml of a 1 N KOH solution. These traps consisted of capped culture tubes with openings cut near the bottom to allow headspace ga s contact with the trap solution as the reaction mixtures were agitated.
- Other: n/a

SAMPLING
- Sampling frequency: Not specified
- Sampling method used per analysis type: Not specified
- Sterility check if applicable: Not specified
- Sample storage before analysis: Not specified - Other: Not specified

DESCRIPTION OF CONTROL AND/OR BLANK TREATMENT PREPARATION
CONTROL AND BLANK SYSTEM
- Inoculum blank: Not specified
- Abiotic sterile control: Single biologically inhibited control experiments were prepared for each configuration to measure potential abiotic losses of TEA. These were prepared in a manner similar to the viable reactions, with the exception that formaldehyde was incorporated at a final concentration of 2.8% (w/v).
- Toxicity control: Not specified
- Other: Not specified

STATISTICAL METHODS:
First-order mineralisation rate constants, determined by fitting the CO2 versus time data to a form of the logistics function previously described by Larson (1984).

Reference substance

Reference substance:

not specified

Results and discussion

Preliminary study:

Not specified

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (test mat. analysis)

Remarks:

experimentally determined first-order half-life for test substance

Value:

ca. 100

Sampling time:

5 d

Remarks on result:

other:

Remarks:

Maximum value, with 5700 µg/L TEA and 164 mg/L MLSS: range 0.10-0.51 days

% Degradation 2

Key result

Parameter:

% degradation (test mat. analysis)

Remarks:

experimentally determined first-order half-life for mineralisation

Value:

ca. 100

Sampling time:

1 d

Remarks on result:

other:

Remarks:

Maximum value, with 5700 µg/L TEA and 164 mg/L MLSS: range 0.24-0.67 days

Details on results:

Kinetics of both primary biodegradation and mineralization appeared to be first-order in TEA concentration over the range of concentrations studied (600 and 5700 µg/L) in both 164 mg/L (lower) or 818 mg/L (upper) mixed liquor suspended solids (MLSS). The first-order half-life for mineralization of TEA (mineralization) in the activated sludge had a maximum of 0.67 d and the first-order half-life for biodegradation of [U-14C]TEA had a maximum of 0.51 days, with % of theoretical CO2 yield of between 52 and 56%.

Radiolabeled intermediate degradation products were detected on a transient basis in each of the viable activated sludge reactions. Maximum yields of these products ranged from 29 to 72% of the initial TEA concentration for all experiments. These products were removed to below detectable levels (<2% of initial TEA concentration) concurrently with TEA removal. Disappearance of [14C]TEA and resultant formation of [14]CO2 in viable reactions was attributed to biological activity associated with the activated sludge. Recovery of TEA in biologically inhibited control reactions ranged from 100 to 126% of the initial concentration over the duration of all experiments.

Biodegradation of TEA was observed in activated slugde within the first sampling time period. The absence of lag periods for TEA biodegradation in the activated sludge reactions indicates that adequate populations of TEA-degrading microorganisms are routinely present in these environmental matrices.

BOD5 / COD results

Results with reference substance:

n/a

Any other information on results incl. tables

Summary of TEA primary biodegradation and mineralisation in activated sludge

Matrix  Initial TEA Concentration (µg/L)   Biodegradation Rate Constant (kb)^a (d^-1) Biodegradation Half-life (d)  Mineralisation Rate Constant (km)^a (d^-1)  Mineralisation Half-life (d)  % Theorectical CO2 Yield (mean +/- SD, n = 2)   164 mg/L    MLSS^b 600 (4.0  µmol/L) 6.86  0.10  1.92  0.36  56 +/- 10  5,700  (38.2µmol/L) 1.36  0.51  1.04  0.67  54 +/- 3   818 mg/L    MLSS 600 (4.0µmol/L)  30.0  0.02  2.86  0.24  55 +/- 1  5,700 (38.2µmol/L)  6.70  0.10  1.69  0.41  52 +/- 0  ^akbandkmrepresent first-order rate constants for primary biodegradation and mineralisation, respectively. ^bMixed liquor suspended solid (MLSS)

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Interpretation of results:

other:

Remarks:

Based on the physical–chemical properties of TEA and the results of this experiment, biodegradation would indeed be the dominant process controlling the fate and lifetime of this material in aquatic environments. Comparison of the half-lives determined for TEA biodegradation and mineralisation to typical chemical residence times in surface water environments indicates that biodegradation should occur to an extent that would prevent accumulation of this compound and its transformation products in the environment.

Conclusions:

Measurement of TEA and its transformation products was achieved through use of a [14C] radiolabelled test material in the biodegradation studies, carried out within an activated sludge system using biomass as mixed liquor suspended solids (MLSS). Duplicate reactions containing each combination of test material and mixed liquor solids concentrations were prepared in 500 mL polypropylene Erlenmeyer flasks. Radiolabelled TEA was added to the activated sludge system to yield approximately 0.7 µCi/mL activity. Additional TEA was added as a concentrated aqueous solution to yield total concentrations of 4.0 and 38.2 µmol/L (600 and 5700 µg/L). Evolved 14C-CO2 was trapped and quantified. The dissipation of [U14C]-TEA over time was followed by HPLC coupled with radiochemical detection.
Degradation of TEA was found to be rapid, with a first-order half-life ranging from 0.10 to 0.51 days, depending on initial concentration of TEA and concentration of MLSS.
Based on the physical–chemical properties of TEA and the results of this experiment, biodegradation would indeed be the dominant process controlling the fate and lifetime of this material in aquatic environments, and TEA can be considered as being rapidly biodegraded by activated sludge.

Executive summary:

The degradation of radiolabelled TEA ([U-14C]TEA) within an activated sludge system was investigated using biomass in the form of mixed liquor suspended solids (MLSS), collected from a Wastewater Treatment Plant. Duplicate samples containing different combinations of test material and MLSS concentrations were incubated in the dark for up to 144 hours at 25C, with gentle agitation. The dissipation of  [U14C]-TEA over time was followed by HPLC coupled with radiochemical detection, and evolved 14CO2 was also trapped and quantified.

Degradation of TEA was found to be rapid, with a first-order half-life ranging from 0.10 to 0.51 days, depending on initial concentration of TEA and concentration of MLSS.

Based on the physical–chemical properties of TEA and the results of this experiment, biodegradation would indeed be the dominant process controlling the fate and lifetime of this material in aquatic environments, and TEA can be considered as being rapidly biodegraded by activated sludge.

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