Reaction mass of (R)-cyano(3-phenoxyphenyl)methyl rel-(1R,3R)-3-((1Z)-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylate and (R)-cyano(3-phenoxyphenyl)methyl rel-(1S,3S)-3-((1Z)-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylate

Phototransformation in water

Administrative data

Endpoint:

phototransformation in water

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

September 2005- November 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study was conducted in compliance with GLP and OECD Guidelines for the Testing of Chemicals (Phototransfonnation of Chemicals in Water- Direct and Indirect Photolysis - Draft, August 2000) and Japanese Ministry of Agriculture, Forestry and Fisheries, Test Data for Registration of Agricultural Chemicals, 12 Nousan No 8147, Agricultural Production Bureau, November 24,2000 revised 26th June 2001.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline draft (Phototransformation of Chemicals in Water - Direct and Indirect Photolysis)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries, Test Data for Registration of Agricultural Chemicals, 12 Nousan No 8147, Agricultural Production Bureau, November 24,2000 revised 26th June 2001

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of (R)-cyano(3-phenoxyphenyl)methyl rel-(1R,3R)-3-((1Z)-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylate and (R)-cyano(3-phenoxyphenyl)methyl rel-(1S,3S)-3-((1Z)-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylate

EC Number:

932-389-6

Molecular formula:

C23H19ClF3NO3

IUPAC Name:

Reaction mass of (R)-cyano(3-phenoxyphenyl)methyl rel-(1R,3R)-3-((1Z)-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylate and (R)-cyano(3-phenoxyphenyl)methyl rel-(1S,3S)-3-((1Z)-2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylate

Study design

Radiolabelling:

yes

Applicant's summary and conclusion

Conclusions:

The study is considered to be reliable.

Executive summary:

The photolysis of cyhalothrin was investigated in natural water treated and maintained under sterile conditions.

¹⁴C-cyclopropyl and¹⁴C-phenoxy labelled cyhalothrin were applied, at a nominal concentration of 0.005 μg m/L, to the sterilised natural water in individual photolysis vessels. The treated solutions were continuously irradiated using light from a xenon arc lamp, which emitted light filtered to give a spectral distribution close to that of natural sunlight. The samples were maintained at 25°C ± 2°C and were irradiated for periods up to 16 days (equivalent to 17 – 18 days summer sunlight at 30 – 50°N and 57 days Tokyo spring sunlight). Duplicate samples (one¹⁴C-cyclopropyl-Iabelled and one¹⁴C-phenoxy-Iabelled) were taken for analysis at 7 intervals during irradiation, including zero-time samples. Duplicate "dark control" samples were also prepared and maintained at 25 ± 2°C °C for 16 days, after which they were analysed. The mean mass balance for irradiated samples treated with¹⁴C-cyclopropyllabelled cyhalothrin was 96.0 %, of which up to 7.7 % was characterised as¹⁴C02. The mean mass balance for irradiated samples treated with 14C-phenoxy labelled cyhalothrin was 94.7 %, of which up to 13.8 % was characterised as¹⁴C02. The entire volatile radioactivity trapped in this study was assumed to be due to¹⁴C02 based on the characterization of radioactivity regenerated from the precipitation.

Degradation of cyhalothrin followed first order kinetics. The estimated overall half-life was 4.9 days of continuous irradiation. Degradation was observed in the "dark controls", indicating that the degradation in irradiated samples was not due to photodegradation alone. As sterility had been maintained, this degradation was assumed to have been hydrolytic. This overall halflife was adjusted to account for this hydrolytic degradation by substracting the dark control rate constant from the overall rate constant. The photolytic half-life was, therefore, 5.4 days of continuous irradiation, which was equivalent to 5.9 - 6.2 days of summer sunlight at latitudes of 30,40 and 500N and 19.5 days of Tokyo spring sunlight.

Two degradates were observed from irradiation¹⁴C-cyc1opropyllabelled samples, Compound la (maximum of 39.2 % after 16 days irradiation) and Compound Ib (maximum of 13.6 % after 14days irradiation). No other degradate was observed at levels of greater than 10% of applied radioactivity.

Three degradates were observed from irradiation¹⁴C-phenoxy labelled samples, Compound V(maximum of 19.7 % after 7 days irradiation), Compound IV (maximum of 11.5 % after 7 days irradiation) and Compound VI (maximum of 4.4 % after 10 days irradiation). No other degradate was observed at levels of greater than 10% of applied radioactivity.

Compound la was observed in the 14C-cyc1opropyllabelled dark control sample at a level of 19.8 % of applied radioactivity. No Compound Ib was observed in this sample, suggesting that this was a product of photo-isomerism. No other degradate was observed at > 5 % of applied radioactivity.

Only one degradate was observed in the 14C-phenoxy labelled dark control sample, namely Compound IV at a level of 13.1 % of applied radioactivity.

The cyhalothrin isomer ratio was altered by irradiation. After irradiation, the remaining cyhalothrin was predominantly comprised of thetrans-D'isomer pair.

.