4,4'-isopropylidenediphenol

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:

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.