Trichloroethylene

Phototransformation in water

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in water

Type of information:

experimental study

Adequacy of study:

key study

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

Study type:

direct photolysis

Principles of method if other than guideline:

Aliquots of 15 ml 1.00 ppm solution were placed in quartz tubes, which were placed horizontally on a tray on the roof of the laboratory.
The tubes were washed once a week during the entire experiment. Tubes were removed periodically for analysis by a hollow fiber-mass spectroscopic method.

GLP compliance:

no

Radiolabelling:

no

Analytical method:

other: hollow fiber-mass spectroscopy

Light source:

sunlight

Type of sensitiser:

not specified

Details on test conditions:

15 ml of the test solution was placed in 22-mm i.d. x 53-mm quartz tubes. The ice cooled tubes, previously constricted at the neck, were sealed. The tubes were placed horizontally on a tray on the roof of the laboratory. The tubes were washed once a week during the entire experiment to remove soot and (or) snow and shaken once a week during the entire year. The temperature range of these tube was estimated to be between -20 and 40 oC. Tubes were removed periodically for analysis.

Duration:

1 yr

Initial conc. measured:

1 mg/L

Dark controls:

yes

Key result

% Degr.:

>= 70 - < 79

Sampling time:

1 yr

Test condition:

outdoor exposure

Rate constant (for indirect photolysis):

0.105 other: month-1

Key result

DT50:

6.6 mo

Test condition:

outdoor conditions

Transformation products:

not specified

Conclusions:

Trichloroethylene (1 mg/l) in water was degraded by 52-56% after one year in the dark and by 70-79% in the presence of sunlight.

Description of key information

Degradation of trichloroethylene in water by photolysis is slow, with a half-life of 201 days (6.6 month)

Key value for chemical safety assessment

Half-life in water:

201 d

Additional information

Photolysis is not likely to be a significant removal process for trichloroethylene.

Trichloroethylene (1 mg/l) in water was degraded by 52-56% after one year in the dark and by 70-79% in the presence of sunlight (Dilling et al., 1975).