Propargite

Field studies

Administrative data

Endpoint:

field studies

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23rd August 2002 to 3rd January 2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

See field "Any other information on materials and methods incl. tables" for information.

GLP compliance:

yes

Type of measurement:

Field dissipation of residues

Media:

Soil

Test material

Test material information

Constituent 1

Reference substance name:

Propargite

EC Number:

219-006-1

EC Name:

Propargite

Cas Number:

2312-35-8

Molecular formula:

C19H26O4S

IUPAC Name:

propargite

Details on test material:

- Name of test material (as cited in study report): Omite 570 EW
- Storage condition of test material: ambient temperature

Results and discussion

Any other information on results incl. tables

Samples were stored for up to 397 days and storage stability was demonstrated over this timescale. The mean overall procedural recovery was 89 % (n = 67, RSD = 16.4). Details of the mean measured propargite residues in the 0-10 cm layer are given in Table 2. Residues in the 10-20 cm layer were always below the Limit of Quantification (0.05 mg/kg) except on day 1 at the Italian site when a value of 0.05 mg/kg was obtained in one replicate. Residues in the untreated plots were always below the Limit of Quantification. First-order dissipation DT50 and DT90 values in the 0-10 cm layer were calculated using a non-linear regression program and can be found in Table 3.

Table 2: Mean residues of propargite in the 0-10 cm layer

Northern France		Germany		Italy		Southern Spain
Day after application	Propargite (mg/kg dw)	Day after application	Propargite (mg/kg dw)	Day after application	Propargite (mg/kg dw)	Day after application	Propargite (mg/kg dw)
-0	<0.05	-0	<0.05	-0	<0.05	-0	<0.05
0	0.720	0	0.665	0	0.730	0	0.5825
1	0.605	1	0.480	1	0.465	1	0.465
7	0.575	7	0.375	7	0.3675	7	0.310
15	0.300	14	0.285	14	0.515	14	0.305
28	0.185	27	0.180	29	0.255	28	0.355
41	0.175	43	0.175	42	0.345	42	0.170
69	0.215	74	0.165	70	0.0225	71	0.095
97	0.270	103	0.115	98	0.225	99	0.110
125	0.230	127	0.100	131	0.450	126	0.110
153	0.260	154	0.090	155	0.340	155	0.050
208	0.185	204	0.105	208	0.145	201	0.055
285	0.070	285	<0.05	285	<0.05	284	<0.05
362	<0.05	369	<0.05	363	<0.05	369	<0.05

Table 3: DT50 and DT90 values

Site	DT50 (days)	DT90 (days)	r^2
Northern France	90*	298*	0.78
Germany	28	94	0.85
Italy	64**	213**	0.78
Southern Spain	38	128	0.89

*data from day 28 and 41 were visually excluded from regression analysis as outliers

**data from day 131 and 155 were visually excluded from regression analysis as outliers

Applicant's summary and conclusion

Conclusions:

Under the conditions of the test, first order dissipation DT50 and DT90 values at four field sites (Northern France, Germany, Italy, Southern Spain) ranged from 28-90 days and 94-298 days, respectively. Residues of propargite were found to remain primarily in the surface 10 cm of soil, and were not typically quantifiable in the 10-20 cm layer, demonstrating the test material's limited soil mobility.

Executive summary:

Four residue trials were conducted on soil, one in Northern France, one in Germany, one in Italy and one in Southern Spain. A single application of Omite 570 EW was applied at a nominal rate of 1280 g a.i./ha to bare soil at each site, diluted with water immediately prior to application to a spray volume of 300 L/ha. Soil specimens were taken immediately prior to application for characterisation and microbial biomass analysis.

30 cm soil core specimens from the treated plots were taken by using a soil auger immediately prior to application, 1, 7, 14, 28, 42, 70, 98, 126, 154, 204 and 284 days and 52 weeks after the final application. Untreated plots were taken immediately prior to application, 28, 126 days and 52 weeks after the final application. Residue analysis was performed on the 0-10 and 10-20 cm horizons only.

Crop specimens were analysed for residues of propargite. This method involves extraction with acetone followed by purification using dichloromethane and re-dissolving in hexane followed by quantitation using GC.

The LOD of propargite in soil is set at 0.05 mg/kg.

The overall mean recovery for soil/propargite is 89 %.

Untreated and treated specimens received a duplicate. No residues above the LOD were found in any of the untreated specimens. Soil residues of propargite were found to remain primarily in the surface 10 cm of soil, demonstrating the test material's limited soil mobility. Residues of propargite in soil were typically not quantifiable at a depth of 10 to 20 cm at any of the sites.

First order DT50 values were calculated from the average concentrations in the 0-10 cm layer using a non-linear regression technique. In the approach taken, both the rate constant and the initial concentration were varied to optimise the fit.

At the the Northern France site, some variability in the concentrations was seen over time and, in the curve fitting process, the data at 28 and 41 days were excluded as outliers. At the Italian site, similar variability was seen in the concentrations over time and, in the curve fitting process, the data at 131 and 155 days were excluded as outliers. Measured soil concentrations over time, including the outliers, are shown below:

Country	DT50 (days)	DT90 (days)	R2
Northern France	90	298	0.78
Germany	28	94	0.85
Italy	64	213	0.78
Southern Spain	38	128	0.89