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Environmental fate & pathways

Phototransformation in water

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Endpoint:
phototransformation in water
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1996
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
unsuitable test system
Remarks:
Acetone is a photosynthesizer and should therefore not be used for the purpose of a photolysis study
Study type:
not specified
Qualifier:
no guideline followed
Principles of method if other than guideline:
Photolysis of Hexachlorocyclopentadiene in acetone. Radiolabelled substance was exposed to 15 Watt UV lamps for 15 days with sampling at 0, 15 min, 30 min, 2-h, 8-h, 1-day, 5-day, 8-day, and 15-day intervals
GLP compliance:
not specified
Radiolabelling:
yes
Analytical method:
gas chromatography
high-performance liquid chromatography
other: thin layer chromatography
Details on sampling:
- Sampling intervals for the parent/transformation products: 0, 15 min, 30 min, 2-h, 8-h, 1-day, 5-day, 8-day, and 15-day intervals
Light source:
other: UV lamps
Details on light source:
15 watt UV lamps (GE Champion Germicidal G15T8)
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test apparatus/vessels: 20 ml screw-capped Pyrex culture tubes
Reference substance:
not specified
Dark controls:
not specified
Details on results:
The half-life of hexachlorocyclopentadiene was below 1 day with no trace of Hex after 15 days. Most of the degradation products were more polar than the test substance as examined by GC. Some of these products appeared to be the same as the ones resulting from the hydrolysis of the substance. Apolar degradation products were also detected.
Validity criteria fulfilled:
not applicable
Conclusions:
The photolysis of Hexachlorocyclopentadiene resulted in the substance having a half-life < 1 day. No traces of the substance were detected after 15 days of photolysis.
Executive summary:

The photolysis of hexachlorocyclopentadiene in acetone was assessed. The substance was exposed for 15 days to two 15 Watts UV lamps. The photolysis of Hexachlorocyclopentadiene resulted in the substance having a half-life < 1 day. No traces of the substance were detected after 15 days of photolysis.

Endpoint:
phototransformation in water
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1982
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Study type:
not specified
Qualifier:
no guideline followed
Principles of method if other than guideline:
Photolysis of hexachlorocyclopentadiene in water irradiated with a mercury vapour lamp.
GLP compliance:
no
Radiolabelling:
yes
Details on sampling:
- Sampling method: Roller mill
Light source:
other: 450 Watt medium-pressure mercury vapour lamp
Details on light source:
A 450 Watt medium-pressure mercury vapour lamp (N° 7825-34, Ace Glass Inc) was used with the following output:
- 40 to 48% ultraviolet;
- 40 to 43% visible;
- infrared radiation (remainder).
Details on test conditions:
TEST SYSTEM
- Type, material and volume of test apparatus/vessels: 1-liter capacity photoreactor with stopcock (N° 7844-12, Ace Glass Inc) and borosilicate immersion well (N° 7857-10, Ace Glass Inc)

TEST MEDIUM
- Volume used/treatment: Distilled water
Dark controls:
yes
% Degr.:
100
Sampling time:
10 min
% Degr.:
100
Sampling time:
5 h
DT50:
1.03 min
Transformation products:
yes
Details on results:
The substance is rapidly converted to ethyl acetate extractable compounds (36%) and water soluble compounds (44%). Pentachlorocyclopentenone may be the primary photoproduct.
Validity criteria fulfilled:
not specified
Conclusions:
The half-life of hexachlorocyclopentadiene was determined to be less than 1.03 minutes. No substance was detected after 10 minutes. The substance is rapidly converted to ethyl acetate extractable compounds (36%) and water soluble compounds (44%). Pentachlorocyclopentenone may be the primary photoproduct.
Executive summary:

The photolysis of hexachlorocyclopentadiene in water was assessed using a mercury vapour lamp. The half-life of hexachlorocyclopentadiene was determined to be less than 1.03 minutes. No substance was detected after 10 minutes. The substance is rapidly converted to ethyl acetate extractable compounds (36%) and water soluble compounds (44%). Pentachlorocyclopentenone may be the primary photoproduct.

Description of key information

The photolysis of Hexachlorocyclopentadiene in water was investigated using a mercury vapour lamp. The half-life of hexachlorocyclopentadiene was determined to be less than 1.03 minutes. No substance was detected after 10 minutes. It was rapidly converted to ethyl acetate extractable compounds (36%) and water soluble compounds (44%). Pentachlorocyclopentenone may be the primary photoproduct.

In addition the photolysis of Hexachlorocyclopentadiene was assessed using acetone instead of water. The results were consistent with the outcome of the photolysis study performed in water.

Key value for chemical safety assessment

Half-life in water:
1.03 min

Additional information