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Environmental fate & pathways

Phototransformation in water

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Administrative data

Endpoint:
phototransformation in water
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Incomplete evaluation of rate coefficients. Determination of the effects in natural sunlight were not assessed.

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Photodecomposition of chlorine dioxide and chlorite by U.V.-irradiation – Part I. Photo-products
Author:
Karpel Vel Leitner N, De Laat J and Dore M
Year:
1992
Bibliographic source:
Wat. Res., 26 (12): 1655-1664
Reference Type:
publication
Title:
Photodecomposition of chlorine dioxide and chlorite by U.V.-irradiation – Part II. Kinetic study
Author:
Karpel Vel Leitner N, De Laat J and Dore M
Year:
1992
Bibliographic source:
Wat. Res., 26 (12): 1665-1672

Materials and methods

Study type:
direct photolysis
Principles of method if other than guideline:
The photolysis of chlorine dioxide and sodium chlorite was assessed using batch reactors equipped with a mercury vapour lamp. Photodegradation tests were performed at 20 °C and pH values ranging from 4 to 8.8 in buffered ultra-pure water. Degradation product concentrations were assessed by HPLC, colorimetric and potentiometric methods.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Chlorine dioxide
EC Number:
233-162-8
EC Name:
Chlorine dioxide
Cas Number:
10049-04-4
Molecular formula:
ClO2
IUPAC Name:
Chlorine dioxide generated from sodium chlorate and hydrogen peroxide in the presence of a strong acid
Details on test material:
Purity: not stated (chlorine dioxide prepared from acidification of sodium chlorite solution).
Solutions of chlorine dioxide were prepared in ultra-pure buffered water (phosphate buffer: 4

Study design

Radiolabelling:
no
Analytical method:
other: acid chrome violet K colorimetric method
Details on sampling:
Not specified
Buffers:
Phosphate buffer: 4
Light source:
other: Low pressure mercury vapour lamp
Light spectrum: wavelength in nm:
253.7
Details on light source:
Incident photonic flux at 253.7 nm = 1.1 E+06 Einstein s-1 and 1.53 E+06 Einstein s-1
Details on test conditions:
Temperature: 20 °C
pH: initial ≈ 7, final ≈ 3 (when carried out in non-buffed ultra-pure water)
Duration of the test: 70 - 130 minutes
Reference substance:
no
Dark controls:
no

Results and discussion

Preliminary study:
Not applicable
Quantum yield (for direct photolysis):
0.27
Transformation products:
yes
Results with reference substance:
Not applicable

Any other information on results incl. tables

Table A7_1_1_1_2-5:       Specification and amount of transformation products from reaction of chlorine dioxide solution with uv light

CAS-Number

CAS and/or IUPAC Chemical Name(s)

Amount [%] of parent compound measured at

pH 7

pH 4

pH 8

-

Chlorate

60 (final)

60 (final)

60 (final)

-

Chlorite (intermediate only – max % indicated)

5 (temporary)

-

Chloride

40 (final)

40 (final)

40 (final)

7782-50-5

Chlorine (intermediate only – max % indicated)

12 (temporary)

Table A7_1_1_1_2-6:       Specification and amount of transformation products from reaction of sodium chlorite solution with uv light

CAS-Number

CAS and/or IUPAC Chemical Name(s)

Amount [%] of parent compound measured at

pH 7

pH 5

pH 8.8

-

Chlorate

40 (final)

40 (final)

40 (final)

10049-04-4

Chlorine dioxide (intermediate only – max % indicated)

12 (temporary)

12 (temporary)

12 (temporary)

-

Chloride

60 (final)

60 (final)

60 (final)

7782-50-5

Chlorine (intermediate only – max % indicated)

17 (temporary)

17 (temporary)

17 (temporary)

Applicant's summary and conclusion

Validity criteria fulfilled:
not applicable