Registration Dossier

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: Study meets generally accepted scientific principles, acceptable for assessment

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Sites of Attack of Hydroxyl Radicals on Amides in Aqueous Solution. II. The Effects on Branching alpha to Carbonyl and to Nitrogen.
Author:
Hayon E, Ibata T, Lichtin NN and Simic M (1971).
Year:
1971
Bibliographic source:
J Am Chem Soc 93(21): 5388-5394.
Reference Type:
publication
Title:
Nitrate-induced photooxidation of trace organic chemicals in water.
Author:
Zepp RG, Hoigné J and Bader H
Year:
1987
Bibliographic source:
Environ Sci Technol 21: 443-450.

Materials and methods

Study type:
indirect photolysis
Test guideline
Qualifier:
no guideline followed
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- test substance: N-Methylacetamide
- purity: no data

Study design

Analytical method:
not specified
Sensitiser (for indirect photolysis)
Type of sensitiser:
OH radical
Details on test conditions:
- source of OH radicals: pulse radiolysis of N2O
- measurement at pH 5-6 under competition with 0.01 M thiocyanate in the presence of 1 atm of N2O
- concentration range: 25-100 mM (1.8-7.31 g/l)
- Rate constant for the reaction of OH radicals with N-methylacetamide in aqueous solution determined by competition with thiocyanate (1.1E10 M-1 s-1): 1.6E9 m-1 s-1

Results and discussion

Dissipation half-life of parent compound
DT50:
> 20.1 - < 1 671 d

Any other information on results incl. tables

As described by Zepp et al. (1987) for the small lake Greifensee in Switzerland, 
the OH radical concentration reaches 2.5E-16 mol/l in the summer time at noon
near the surface. From this "best case", a half-life in terms of aquatic 
photolysis of 20.1 days can be calculated for N-methylacetamide. 
The average OH-radical concentration over the whole water column (14 m) over 
the whole year is 3.0E-18 mol/l. From this, a half-life in terms of aquatic 
photolysis of 4.6 years can be calculated.

Applicant's summary and conclusion