Triethyl O-acetylcitrate

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods

Remarks:

test procedure in accordance with national standard methods EPA method OPPTS 835.3300; ASTM D 5988

Data source

Reference

Reference Type:

grey literature

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3300 (Soil Biodegradation)

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Tributyl O-acetylcitrate

EC Number:

201-067-0

EC Name:

Tributyl O-acetylcitrate

Cas Number:

77-90-7

Molecular formula:

C20H34O8

IUPAC Name:

Acetyltributylcitrate

Specific details on test material used for the study:

99.0% minimum specification

Radiolabelling:

no

Study design

Oxygen conditions:

aerobic

Soil classification:

not specified

Year:

2000

Duration of test (contact time)

Duration:

42 d

Initial test substance concentration

Initial conc.:

>= 0 - <= 12 other: mg C/g dry soil

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on experimental conditions:

A standard laboratory soil mix was prepared, characterized, adjusted to 60% of its water holding capacity (WHC) and preincubated for 48 hours. The soil was amended with 67 to 1149 mg test substance per 50 g dry soil and placed in a 250-ml reactor vessels fitted with a side-arm chamber charged containing 20 ml of 0.5-M KOH. Reactors were similarly prepared for positive (cellulose) and negative controls. Reactors were prepared in triplicate for each treatment, stoppered and incubated in the dark at 30±1°C for 42 days.

Results and discussion

% Degradation

Remarks on result:

other: see table below

Half-life / dissipation time of parent compound

Remarks on result:

other: see table below

Transformation products:

not specified

Details on results:

Substrate decay of the test substance reached 166.8, 124.4, 97.2, 97.4 and 72.9% as ThCO2 by Day 42 in test vessels containing 0.8, 1.6, 3.2, 6.0 and 12.0 mg C/g soil, respectively. Total net mineralization of ATBC (expressed as %ThCO2) varied as a function of substrate concentration.

Any other information on results incl. tables

The mineralization of ATBC in soil over 42 days was as follows:

Substrate Loading (mg C/g soil)	% ThCO2	Lag (days) a	Decay Constant (day^-1) b	t50(days) c	t60(days) d
Cellulose (300)	61.6	3.5	0.1028	32.9	32.9
0.8	166.8	1.5	0.0445	8.4	8.4
1.6	124.4	2	0.0570	10.9	10.9
3.2	97.2	3	0.0485	19.9	19.9
6	97.4	3	0.0362	25.8	25.8
12	72.9	4.5	0.0233	57.9	57.9

a Time required for test substance mineralization to reach 10% MAXCO2.

b Based on % decrease in substrate concentration and calculated using the following equation: y = y0 + a exp(-bx).

c Time required for test substance mineralization to reach 50% ThCO2.

d Time required for test substance mineralization to reach 60% ThCO2.

Applicant's summary and conclusion

Conclusions:

ATBC is considered to be readily biodegradable at concentrations <3.2 mg C/g soil, based on >60% ThCO2 observed within a 10- to 14-day window following the lag.

Executive summary:

ATBC is considered to be readily biodegradable at concentrations <3.2 mg C/g soil, based on >60% ThCO2 observed within a 10- to 14-day window following the lag.