Trichloroethylene

Hydrolysis

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Remarks:

Non-GLP non-guideline experimental study, published in peer reviewed literature, notable limitations in design and/or reporting, but adequate for assessment

Principles of method if other than guideline:

Aliquots of 15 ml 1.00 ppm solution were placed in Pyrex tubes, which were placed in a light-proof conatiner and kept in the laboratory at 25 C.
Tubes were removed periodically for analysis by a hollow fiber-mass spectroscopic method.

GLP compliance:

not specified

Remarks:

study conducted before implementation of GLP

Radiolabelling:

not specified

Analytical monitoring:

yes

Estimation method (if used):

Not specified in report

Details on test conditions:

15 ml of the test solution was placed in 18-mm i.d. x 150-mm Pyrex tubes. The icecooled tubes, previously constricted at the neck, were sealed.
The tubes were placed in a light-proof container and kept in the laboratory at 25 C. The tubes were shaken every week or two.

Duration:

1 yr

Temp.:

25 °C

Initial conc. measured:

1 mg/L

Transformation products:

not specified

% Recovery:

> 44 - < 48

Temp.:

25 °C

Duration:

1 yr

Key result

pH:

7

Temp.:

25 °C

DT50:

10.7 mo

Type:

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

Remarks on result:

other: dark

Conclusions:

The abiotic degradation half-life for trichloroethylene was measured to be 10.7 months using a closed system (Pyrex tubes) in the dark at room temperature of 25°C.

Reference 2

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Remarks:

Published in peer reviewed literature, notable limitations in design and/or reporting, but adequate for assessment

Principles of method if other than guideline:

Hydrolysis of a series of chlorinated hydrocarbon test chemicals was measured in dilute aqueous solutions at varying temperatures(0 to 180 oC) and varying pH (3 to 14) in zero dead-volume stainless steel tubes or flame sealed glass bulbs.

GLP compliance:

not specified

Remarks:

study conducted before implementation of GLP

Transformation products:

not specified

Key result

pH:

7

Temp.:

25 °C

DT50:

1 300 000 yr

A half-life for abiotic degradation of trichloroethylene of 1.3 million years at pH 7 and 25 °C was calculated

Conclusions:

A half-life for abiotic degradation of trichloroethylene of 1.3 million years at pH 7 and 25 °C was calculated.

Reference 3

Endpoint:

hydrolysis

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

(only secondary source), but adequate for assessment

Principles of method if other than guideline:

The half-life for hydrolysis of trichloroethylene has been measured at 25°C and various pHs

GLP compliance:

not specified

Transformation products:

not specified

Key result

pH:

3

Temp.:

25 °C

DT50:

2 809 h

Key result

pH:

7

Temp.:

25 °C

Remarks on result:

other: no hydrolysis observed

Key result

pH:

9

Temp.:

25 °C

DT50:

3 489 h

The half life for hydrolysis of trichloroethylene has been measured at 25°C and various pHs. At pH 3 the half life was 2,809 hours (117 days), at pH 7 no hydrolysis was observed and at pH 9 the half life was 3,489 hours (145 days).

Conclusions:

The half life for hydrolysis of trichloroethylene has been measured at 25°C and various pHs.
At pH 3 the half life was 2,809 hours (117 days), at pH 7 no hydrolysis was observed and at pH 9 the half life was 3,489 hours (145 days).

Description of key information

Hydrolysis is not a significant removal process for trichloroethylene.

Key value for chemical safety assessment

Half-life for hydrolysis:

1 300 000 yr

at the temperature of:

298 K

Additional information

Within a weight of evidence, the endpoint hydrolysis of trichloroethylene was evaluated.

Reliable information from literature is available with consistent evidence to conclude that hydrolysis is not an important removal process for trichloroethylene.

Half-lives in the range from 10.7 months to 1.3 million years have been reported.

The abiotic degradation half-life for trichloroethylene was measured to be 10.7 months using a closed system (Pyrex tubes) in the dark at room temperature of 25°C. (Dilling et al., 1975)

A half-life for abiotic degradation of 1.3 million years at pH 7 and 25 °C was calculated by Jeffers et al., 1989.

Korte reported measured half-life for hydrolysis of trichloroethylene at 25°C and various pHs. At pH 3 the half-life was 2,809 hours (117 days), at pH 7 no hydrolysis was observed and at pH 9 the half-life was 3,489 hours (145 days). (Korte et al., 1981)

The information is in agreement with assessments from European Union and US EPA.