Registration Dossier

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:
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

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Details on test material:
Lot No 4103TH (p-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.