1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-ene-2,3-dicarboxylic anhydride

Phototransformation in air

Administrative data

Endpoint:

phototransformation in air

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: details on experimental conditions are lacking

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Materials and methods

Test guideline

Deviations:

not specified

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-ene-2,3-dicarboxylic acid

EC Number:

204-078-9

EC Name:

1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-ene-2,3-dicarboxylic acid

Cas Number:

115-28-6

Molecular formula:

C9H4Cl6O4

IUPAC Name:

1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid

Test material form:

not specified

Study design

Light source:

not specified

Details on light source:

UV light

Results and discussion

Dissipation half-life of parent compound

Dissipation half-life of parent compound 1

DT50:

16 d

Test condition:

on solid surface

Dissipation half-life of parent compound 2

DT50:

5 d

Test condition:

in aqueous solution

Dissipation half-life of parent compound 3

DT50:

140 d

Test condition:

in soil at 1 mg/kg concentration

Dissipation half-life of parent compound 4

DT50:

280 d

Test condition:

in soil at 10 mg/kg concentration

Applicant's summary and conclusion

Conclusions:

On a solid surface, chlorendic acid was degraded by UV light (half-life = 16 days) to a number of unknown products. The irradiation of chlorendic acid in aqueous solution with UV light showed that the half-life in this system was 5 days. In soil, the half-life of 14C-chlorendic acid was found to be 140 ± 37 days at a soil concentration of 1 mg/kg and 280 ± 35 days at 10 mg/kg. Ozone seems quite effective in dechlorinating chlorendic acid. The rate of dechlorination is affected by pH, UV light and bicarbonate concentration. 80% dechlorination was achieved in 1h with a 125mg/min ozone at pH 7.4.

Executive summary:

              
  From a comparison of the characteristics of the cyclodiene
      
  derivatives, chlorendic acid would be expected, on theoretical grounds, to degrade by direct photolysis or by reactions with hydroxyl
   radicals and ozone (Parlar & Korte, 1977).
 
        An experimental study was conducted to investigate the use of
   ozone to dechlorinate chlorendic acid. The dechlorination and
   subsequent degradation of chlorendic acid by ozonation was influenced
   by the pH, applied ozone dose and bicarbonate concentration. A change
   in the initial chlorendic acid concentration to 50, 100 and
   200 mg/litre did not influence the rate of degradation of chlorendic
   acid. Ultraviolet (UV) radiation alone dechlorinates chlorendic acid.
   UV radiation was also shown to greatly enhance the oxidation of
   chlorendic acid in the presence of ozone. In a typical case, 80%
   dechlorination of chlorendic acid was obtained in 60 min when using an
   ozone dose of 125 mg/min ozone at pH 7.4. Conditions favouring
   radicals in solution, such as high pH and exposure to UV light,
   resulted in much faster dechlorination. The conditions which did not
   favour radicals, such as low pH and the addition of bicarbonate,
   resulted in slower dechlorination (Stowell & Jensen, 1991).
 
        The photolysis of chlorendic acid by UV light and sunlight has
   been determined on solid surface and in aqueous solution. On a solid
   surface, chlorendic acid was degraded by UV light (half-life = 16
   days) to a number of unknown products. The irradiation of chlorendic
   acid in aqueous solution with UV light showed that the half-life in
   this system was 5 days (Yu & Atallah, 1978).
 
        In soil, the half-life of14C-chlorendic acid was found to be
   140 ± 37 days at a soil concentration of 1 mg/kg and 280 ± 35 days at
   10 mg/kg. However, it should be noted that the labelled carbon atoms
 
  From a comparison of the characteristics of the cyclodiene
  derivatives, chlorendic acid would be expected, on theoretical grounds, to degrade by direct photolysis or by reactions with hydroxyl
   radicals
   chlorendic acid in the presence of ozone. In a typical case, 80%
   dechlorination of chlorendic acid was obtained in 60 min when using an
   ozone dose of 125 mg/min ozone at pH 7.4. Conditions favouring
   radicals in solution, such as high pH and exposure to UV light,
   resulted in much faster dechlorination. The conditions which did not
 
   half-lives are more representative of that moiety than of chlorendic
   acid itself. Chlorendic acid can thus be considered fairly persistent
   in soil (Butz & Atallah, 1979a).
   acid itself. Chlorendic acid can thus be considered fairly persistent
   in soil (Butz & Atallah, 1979a).