6,6',6''-(1,3,5-triazine-2,4,6-triyltriimino)trihexanoic acid, compound with 2,2',2''-nitrilotriethanol (1:3)

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: sediment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP non-guideline study, well documented, suitable test system, acceptable for assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Fate of 14C-labeled test substance in an artificial water-sediment system (biodegradation study in river-microcosms)

GLP compliance:

not specified

Radiolabelling:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

natural water / sediment

Details on source and properties of surface water:

- Details on collection (e.g. location, sampling depth, contamination history, procedure): Water and sediment samples were collected from two sites
1) Tittabawassee river near Midland, Michigan, USA (date: 16 June 1992)
2) Chippewa River near Mount Pleasant, Michigan, USA (28 June 1992).
- Procedure: Water samples were collected in sterile amber glass bottles from the upper 1 to 5 cm of the water column near the center of each river.
- Storage conditions: transported on ice to laboratory; stored at 4 °C
- Water filtered: no
- pH at time of collection: 7.7 / 7.7
- Total organic carbon: 8.1 / 8.7
- Total inorganic carbon: 48.7 / 46.6
- Biomass (Bacteria/mL): 6.4E03 / 3.3E03

Details on source and properties of sediment:

- Details on collection (e.g. location, sampling depth, contamination history, procedure): Water and sediment samples were collected from two sites
1) Tittabawassee river near Midland, Michigan, USA (date: 16 June 1992)
2) Chippewa River near Mount Pleasant, Michigan, USA (28 June 1992).
- Procedure: Sediment samples were collected in sterile jars from the upper 5 cm of strata immediately underlying the water collection sites.
- Storage conditions: transported on ice to laboratory; stored at 4 °C
- Textural classification (i.e. %sand/silt/clay): 1) 90% sand, 4% silt, 6% clay; 2) 96% sand, 0% silt, 4% clay
- pH: 8.1 / 7.8
- Organic carbon (%): 0.52 / 0.23
- CEC (meq/100 g): 6.1 / 6.3
- Biomass (bacteria/g d.w.): 2.5E07 / 5.9E06
- Sediment samples sieved: yes (2 mm)

Duration of test (contact time):

> 7 - < 15 d

Initial conc.:

>= 100 - <= 489 µg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

radiochem. meas.

Details on study design:

TEST CONDITIONS
- Volume of test solution/treatment: 1) river water only: 50 mL; 2) sediment-amended river water: 50 mL river water, 10 g d.w. sediment
- Solubilising agent (type and concentration if used): no
- Test temperature: 25 °C
- pH adjusted: no
- Aeration of dilution water: no
- Continuous darkness: yes
- Other: shaken (100 rpm)

TEST SYSTEM
- Culturing apparatus: 100-mL glass serum bottle
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: headspace purged with oxygen gas (>= 99.5% v/v)
- Measuring equipment:
- Test performed in closed vessels due to significant volatility of test substance: bottles sealed with Teflon-faced butyl rubber septa and Al crimp seals
- Details of trap for CO2 and volatile organics if used: Two traps were connected containing 10 mL 1 N NaOH.

SAMPLING
- Sampling frequency: 1) Tittabawassee: primary biodegradation after 0, 1, 2 d; mineralisation after 0, 1, 7 d
2) Chippewa: primary biodegradation after 0, 1, 2, 3 d; mineralisation after 0, 1, 3, 15 d
- Sampling method: CO2 was collected after acidification of the microcosms (pH <=2, 85% H3PO4) and purging with nitrogen gas. Collection of CO2 in traps.

CONTROL AND BLANK SYSTEM
- Abiotic sterile control: yes (biologically inhibited control, 2 % w/w formaldehyde)

% Degr.:

100

Parameter:

test mat. analysis

Sampling time:

2 d

Remarks on result:

other: initial TEA conc.: 100 µg/L; Tittabawassee, sediment-amended river water

% Degr.:

100

Parameter:

test mat. analysis

Sampling time:

3 d

Remarks on result:

other: initial TEA conc.: 100 µg/L; Chippewa, sediment-amended river water

% Degr.:

ca. 100

Parameter:

test mat. analysis

Sampling time:

20 d

Remarks on result:

other: initial TEA conc.: 100 µg/L; Tittabawassee, river water only

% Degr.:

ca. 100

Parameter:

test mat. analysis

Sampling time:

35 d

Remarks on result:

other: initial TEA conc.: 100 µg/L; Chippewa, river water only

Compartment:

other: water-sediment

DT50:

0.2 - 0.6 d

Type:

(pseudo-)first order (= half-life)

Temp.:

25 °C

Remarks on result:

other: Sediment-amended river water; values depending on test concentration and source of sediment and water. First-order half life for mineralization: 1.0 - 7.2 days

Compartment:

water

DT50:

0.8 - 1.7 d

Type:

(pseudo-)first order (= half-life)

Temp.:

25 °C

Remarks on result:

other: River water only; values depending on test concentration and source of water. First-order half life for mineralization: 1.2 - 1.9 days

Transformation products:

not specified

Details on transformation products:

- Formation and decline of each transformation product during test: Degradation products were sporadically detected, but remained below quantification limits. Complete removal coincided with complete removal of TEA

Evaporation of parent compound:

no

Volatile metabolites:

not specified

Residues:

not specified

Details on results:

TEST CONDITIONS
- Aerobicity (or anaerobicity), moisture, temperature and other experimental conditions maintained throughout the study: Yes
- Anomalies or problems encountered (if yes): no

MINERALISATION
- % of applied radioactivity present as CO2 at end of study: River water only: 58% to 64%; Sediment-amended river water: 49% to 63%

STERILE TREATMENTS (if used)
- Transformation of the parent compound: no

Matrix	Initial TEA conc. (µg/L)	Biodegradation		Mineralisation		%Theroretical CO2 yield  (mean±SD, n = 2)
		Rate constant (/d)	Half-life (d)	Rate constant (/d)	Half-life (d)
River water
Chippewa	100	0.402	1.7	not measured	not measured	not measured
Tittabawassee	100	0.685	1.0	0.359	1.9	64±2
	489	0.841	0.8	0.558	1.2	58±3
Sediment-amended river water
Chippewa	100	2.40	0.3	0.724	1.0	52±7
	489	1.07	0.6	0.563	1.2	63±1
Tittabawassee	100	3.25	0.2	0.385	1.8	49±3
	489	1.63	0.4	0.096	7.2	58±1

 

Recovery of TEA in biologically inhibited controls:

water-sediment: 92-100%

river: 100-126%

 

Incorporation of sediment into the test matrix did not result in increased abiotic losses of the test material.

Validity criteria fulfilled:

yes

Conclusions:

TEA is rapidly biodegraded and mineralized within a sediment-water test system.

Description of key information

Triethanolamine is rapidly biodegraded and mineralized within a sediment-water test system.

Additional information

For the purpose of this registration data on the biodegradation in water and sediment: simulation tests are not required. The present compound consists of a triazine part and an amine part. Under environmental conditions it is present in its dissociated form. Data for the present endpoint are only available for the amine part CAS 102 -71 -6.

A key study regarding biodegradation of the amine part in a sediment-water microcosm test performed by West et al. (1996) is identified. In a sediment-water microcosm-study with natural sediment and water samples a maximum biodegradation half-life of 0.6 days and a maximum mineralization half-life of 7.2 days was found, depending on the initial concentration of the test substance and the origin of the test water and sediment.

In a river-water microcosm-study with natural river water samples a maximum biodegradation half-life of 1.7 days and a maximum mineralization half-life of 1.9 days was found, depending on the initial concentration of the test substance and the origin of the test water and sediment.