Trimethyl orthoformate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2002-02-15 to 2002-05-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: ISO/DIS 14593 (1997)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of activated sludge: Marl-Ost municipal sewage treatment plant
- Storage conditions: Under aeration in the dark
- Storage length: Six days
- Preparation of inoculum for exposure: Aeration of inoculum in mineral medium for six days.
- Concentration of sludge: Dry matter content in inoculum was 3.05 g/L. Content of colony forming units (CFU) was 370000 CFU/mL
- Initial cell/biomass concentration: 5.2 mg/L
- Bidestilled water was used for the preparation of the mineral medium

Duration of test (contact time):

28 d

Initial conc.:

49.2 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

inorg. C analysis

Details on study design:

TEST CONDITIONS
The test was carried out in accordance with Directive 92/69/EEC C.4-C, OECD 301 B and ISO/DIS 14593.
- Composition of medium: carried out to guideline, with bidest. water
- Test temperature: 20.6-22.7°C (mean 21.8°C)
- pH: Measured at the end of the test
Blank pH7.5
Sodium benzoate pH7.0
Trimethylorthoformate pH6.9
- Aeration of dilution water: sealed vessels
- Suspended solids concentration: Initial 5.2 mg/L
- Continuous darkness: yes
- Test vessles placed on an orbital shaker and shake with 180 rpm

TEST SYSTEM
- Culturing apparatus: ca 210 ml gas-tight glass vessels sealed with butyl rubber septa and aluminium crimp seals.
The test material was dosed to a defined volume of liquid mineral medium which was already inoculated with an activated-sludge inoculum.
- Number of culture flasks/concentration:
20 vessels without test item with inoculum
20 vessels containing reference item and inoculum
20 vessels containing test item and inoculum
- Measuring equipment: Evolved CO2 measured via TIC analysis in a Shimadzu carbon analyser


SAMPLING
- Sampling frequency: sampling after 0, 3, 7, 10, 14, 21 and 28 days
- Sampling method: Sacrificial vessels. TIC analysis of the bound CO2


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
No other controls

STATISTICAL METHODS:
Calculations performed with Excel

Reference substance:

benzoic acid, sodium salt

Preliminary study:

No preliminary test was performed

Test performance:

All validity criteria were fulfilled

Parameter:

% degradation (inorg. C analysis)

Value:

88

Sampling time:

10 d

Details on results:

Since the degradation of Trimethylorthoformate was > 60 % in the course of 10 days after the lag phase (10% biodegradation), Trimethylorthoformate is considered to be „readily biodegradable".

Trimethylorthoformat was completely mineralised (108%) over the 28 day test period.

Results with reference substance:

The reference item sodium benzoate was completely mineralised (97 % degradation) over the 28 day test period. It can be concluded that the inoculum used had a sufficient biological activity.

 

Concentration: 49.2 mg/L => 22.3 mg C/L

                        2.9 mg C/vessel

  

Test duration (days)	TIC (mg/L)		TIC (mg/vessel)		Degradation %	Degradation %
	test item	mean of the blank value	test item	mean of the blank value		mean
0	1.86	1.98	0.24	0.26	-0.69	-1
0	1.74	1.98	0.23	0.26	-1.03
3	9.86	1.98	1.28	0.26	35.17	36
3	10.04	1.98	1.31	0.26	36.21
7	17.07	2.00	2.22	0.26	67.59	68
7	17.40	2.00	2.26	0.26	68.97
10	22.62	2.02	2.94	0.26	92.41	88
10	20.64	2.02	2.88	0.26	83.45
14	23.76	2.20	3.09	0.29	96.55	93
14	22.29	2.20	2.90	0.29	90.00
21	24.87	1.96	3.23	0.25	102.76	101
21	23.82	1.96	3.10	0.25	98.28
28	27.33	2.22	3.55	0.29	112.41	108
28	25.23	2.22	3.28	0.29	103.10

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Trimethylorthoformate is considered to be „readily biodegradable”.

Executive summary:

The ready biodegradability of Trimethylorthoformate (CAS 149-73-5) was tested according to OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test, 1992) or EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test, 1992). Activated sludge from the Marl-Ost municipal sewage treatment plant was used in the test. The test material (Trimethylorthoformate, 99.5% purity) was dosed at 49.2 mg/L .

Since the degradation of of the test substance was > 60 % in the course of 10 days after the lag phase (10% biodegradation), Trimethylorthoformate is considered to be „readily biodegradable”.

The reference item sodium benzoate was completely mineralised (97 % degradation) over the 28 day test period. It can be concluded that the inoculum used had a sufficient biological activity.

Description of key information

Readily biodegradable, OECD 301B

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The guideline study of Ernst & Diefenbach (2002), which is considered to be reliable and accurate concludes that trimethylorthoformate is readily biodegradable. The study is considered reliable for classification and for use in risk assessments.