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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

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Diss Factsheets

Environmental fate & pathways

Phototransformation in water

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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
phototransformation in water
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Study type:
other: direct and indirect photolysis
Principles of method if other than guideline:
Measurement of direct and indirect photolysis in the presence of dissolved organic matter
GLP compliance:
not specified
Radiolabelling:
no
Light source:
other: Suntest CPS+ solar simulator (Atlas Devices)
DT50:
22 h
Test condition:
River fulvic acids
DT50:
17.4 h
Test condition:
Lake fulvic acids
DT50:
32.2 h
Test condition:
Artificial wetlands
DT50:
235 h
Test condition:
Control in deionised water
Transformation products:
not measured

DIRECT PHOTOLYSIS:

Some loss of bisphenol A was reported in the controls (Milli-Q water, no DOM) held under light. A pseudo-first order rate constant of 8.07E-7 / sec was calculated. This yields a half-life of 235 hours or 9.8 days.

INDIRECT PHOTOLYSIS:

Observed rate constants (Kobs) and half-lives (t1/2):

River fulvic acids: Kobs = 86.2 E-7 /sec; t1/2 = 22.0 hours

Lake fulvic acids: Kobs = 111 E-7 /sec; t1/2 = 17.4 hours

Artificial wetlands: Kobs = 59.8 E-7 /sec; t1/2 = 32.2 hours

CONCLUSION:

Bisphenol A degradation in the presence of dissolved organic matter (DOM) under natural sunlight may result in photo-degradation rate coefficients that are significantly higher than, or at least on the order of, those reported for biodegradation. Depending upon the latitude of the water body, the season, and the DOM levels present in the water body, this translates into half-lives on the order of or faster than degradation by microorganisms.

Conclusions:
Bisphenol A has a half-life of 235 h for direct photolysis and 17.4 to 32.2 h for indirect photolysis.
Executive summary:

Bisphenol A has a half-life of 235 h for direct photolysis and 17.4 to 32.2 h for indirect photolysis.

Description of key information

Bisphenol A has a half-life of 0.5 to 10 days for direct photolysis and 0.7 to 1.3 days for indirect photolysis.

Key value for chemical safety assessment

Half-life in water:
0.5 d

Additional information

Bisphenol A may undergo both direct and indirect photolysis in water. Direct photolysis half-lives of 0.5 to 10 days have been reported from laboratory experiments. Indirect photolysis (in the presence of various dissolved organic matter) half-lives of about 0.7 to 1.3 days have been reported from laboratory experiments.