Terphenyl, hydrogenated

Phototransformation in water

Administrative data

Endpoint:

phototransformation in water

Type of information:

other: Study on constituent of the UVCB substance.

Adequacy of study:

supporting study

Study period:

Exposure period from7 July to 5 August 1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented report which meets basic scientific principles. This study is added to the substance dataset in function of the PBT assessment. It concerns one of the constituents of the UVCB substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Study type:

direct photolysis

Test guideline

Qualifier:

according to guideline

Guideline:

other:

Deviations:

yes

Principles of method if other than guideline:

similar to the method described by Saeger V.W. and Adams W.J. “Method for conducting Sunlight photolysis screening of organic chemicals in aqueous solution”, Monsanto Report ES-81-M-23

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

o-terphenyl

EC Number:

201-517-6

EC Name:

o-terphenyl

Cas Number:

84-15-1

Molecular formula:

C18H14

IUPAC Name:

1,1':2',1''-terphenyl

Constituent 2

Reference substance name:

m-terphenyl

EC Number:

202-122-1

EC Name:

m-terphenyl

Cas Number:

92-06-8

Molecular formula:

C18H14

IUPAC Name:

1,1':3',1''-terphenyl

Constituent 3

Reference substance name:

p-terphenyl

EC Number:

202-205-2

EC Name:

p-terphenyl

Cas Number:

92-94-4

Molecular formula:

C18H14

IUPAC Name:

1,1':4',1''-terphenyl

Study design

Radiolabelling:

no

Analytical method:

gas chromatography

Details on sampling:

Sampling for the parent compounds:day 0, 1, 3, 7, 14 and 29

Light source:

sunlight

Duration of test at given test condition

Duration:

29 d

Temp.:

90 °F

Initial conc. measured:

20 other: mg/l (o- and m), 10 mg/l (p-)

Results and discussion

Spectrum of substance

Parameter:

not specified

Dissipation half-life of parent compound

DT50:

ca. 140 d

Test condition:

for m-terphenyl

Transformation products:

not specified

Any other information on results incl. tables

The results of the photolysis study on the 3 isomers are summarized in Table 2. The concentrations found for each sampling day are expressed as a percentage of the concentration pound at day 0.

It can be seen that for o- and p- terphenyl , the concentrations were constant, within experimental error, over the 29 day period.

Table 2: Photolysis results – percentage of compound remaining after exposure relative to concentration on day 0
Sampling day	o-Terphenyl	m-Terphenyl	p-Terphenyl
0	100	100	100
1 Exposed 1 Dark	86 96	105 108	62 93
3 Exposed 3 Dark	93 95	98 96	107 111
7 Exposed 7 Dark	95 89	86 96	93 97
14 Exposed 14 Dark	95 98	103 113	108 115
29 Exposed 29 Dark	92 91	76 88	90 101

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Three terphenyl isomers were tested for direct photolysis with sunlight during a 29 day period. The o- and p-isomer showed no significant decrease in concentration after 29 days of sunlight exposure, indicating that they are not susceptible to direct aqueous photolysis by sunlight. For m-terphenyl the half-life was calculated to be 140 days.
For none of the three terphenyl isomers photolysis is expected to be a significant pathway for transformation in aqueous solution.

Executive summary:

Polyphenyls are strong absorbers of UV light. It is well established that many compounds that absorb visible and UV light undergo rapid photodegradation in the environment. The purpose of this study was to examine the photolytic behavior of some compounds in the polyphenyl family to determine if

1)     they are likely to photodegrade In the environment and

2)     a relationship exists between compound structure and activity.

For the six compounds tested, biphenyl, cyclohexylbenzene, bicyclohexyl, o-, m- and p-terphenyl photolysis is not expected to be a significant pathway for transformation in aqueous solution.