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

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented publication, suitable test system used, though non-guideline non-GPL study acceptable for assessment.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Fate of the test substance in soil. Measurement of mineralisation. Use of 14C-labeled test substance.

GLP compliance:

not specified

Test type:

laboratory

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

USDA (US Department of Agriculture)

Year:

1979

Soil no.:

#1

Soil type:

sandy loam

% Clay:

ca. 10

% Silt:

ca. 18

% Sand:

ca. 72

% Org. C:

2.4

pH:

7.7

CEC:

9.7 meq/100 g soil d.w.

Details on soil characteristics:

SOIL COLLECTION AND STORAGE
- Geographic location: non-cultivated plot in Midland, Michigan
- Pesticide use history at the collection site: none
- Sampling depth (cm): 15 cm
- Soil preparation (e.g., 2 mm sieved; air dried etc.): 2 mm sieved
- Storage: at 4°C with a field moisture of 9% w/w

Soil No.:

#1

Duration:

>= 8 - <= 15 d

Soil No.:

#1

Initial conc.:

1.4 mg/kg soil d.w.

Based on:

test mat.

Soil No.:

#1

Initial conc.:

201 mg/kg soil d.w.

Based on:

test mat.

Soil No.:

#1

Initial conc.:

2 000 mg/kg soil d.w.

Based on:

test mat.

Parameter followed for biodegradation estimation:

radiochem. meas.

Soil No.:

#1

Temp.:

25°C

Humidity:

no data

Microbial biomass:

6.6E06 bacteria/g d.w.

Details on experimental conditions:

1. PRELIMINARY EXPERIMENTS:

2. EXPERIMENTAL DESIGN
- Soil condition: fresh
- Soil (g/replicate): 20 (d.w.)
- Control conditions, if used (present differences from other treatments, i.e., sterile/non-sterile, experimental conditions): sterilised soil (autoclaved (60 min, 121 °C, 15 psi on three consecutive days)
- Test apparatus (Type/material/volume): batch microcosm experiments performed in 100-mL glass serum bottles sealed with Teflon-faced butyl rubber septa and aluminum crimp seals
- Details of traps for CO2 and organic volatile, if any: Two traps were connected containing 10 mL 1 N NaOH.
- If no traps were used, is the system closed/open: closed

Test material application
- Volume of test solution used/treatment: 20 mL deionised water
- Application method (e.g. applied on surface, homogeneous mixing etc.): mixed (shaken (100 rpm) )

Experimental conditions (in addition to defined fields)
- Moisture maintenance method: cosed system
- Continuous darkness: Yes

3. OXYGEN CONDITIONS (delete elements as appropriate)
- Methods used to create the an/aerobic conditions: headspace purged with oxygen gas (>= 99.5% v/v)

4. SAMPLING DETAILS
- Sampling intervals: not specified
- Sampling method for soil samples:
- Method of collection of CO2 and volatile organic compounds: CO2 was collected after acidification of the microcosms (pH <=2, 85% H3PO4) and purging with nitrogen gas. Collection of CO2 in traps.

Soil No.:

#1

% Degr.:

100

Parameter:

test mat. analysis

Remarks:

(initial TEA conc.: 1.4 mg/kg dw)

Sampling time:

2 d

Soil No.:

#1

% Degr.:

100

Parameter:

test mat. analysis

Remarks:

(initial TEA conc.: 201 mg/kg dw)

Sampling time:

7 d

Soil No.:

#1

DT50:

>= 0.5 - <= 1.8 d

Type:

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

Remarks on result:

other: Degradation half-life depends on the concentration of the test substance. Mineralization half-lifes: >= 1.4 - <= 5.4 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: 46% to 56%

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

TEA primary biodegradation and mineralisation

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)
1.4	1.38	0.5	0.406	1.7	55±3
201	0.607	1.1	0.498	1.4	56±1
2000	0.380	1.8	0.129	5.4	46±17

Conclusions:

TEA is rapidly biodegraded and mineralized in soil.

Description of key information

Triethanolamine is rapidly biodegraded and mineralized in soil under semi-realistic conditions.

Additional information

For the purpose of this registration data on the biodegradation in soil is 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.

As key study regarding the biodegradation of the amine part in soil performed by West et al. (1996) is identified. Depending on the initial test substance concentration under semi-realistic conditions with soil microcosms using natural sandy loam soil a maximum biodegradation half-life of 1.8 days and a maximum mineralization half-life of 5.4 days were determined.