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Environmental fate & pathways

Field studies

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Administrative data

Endpoint:
field studies
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
not documented
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:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: BBA Guideline Part IV, 4-1
Deviations:
no
GLP compliance:
yes
Type of measurement:
Residues
Media:
Soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: granular
Details on test material:
- Name of test material (as cited in study report): Casoron G
- Physical state: solid
- Composition of test material, percentage of components: 6.75 % dichlobenil
- Lot: MI-0935

Results and discussion

Any other information on results incl. tables

Untreated samples of Goch-Nierswalde (1989) were used for preparation of spiked samples. The limit of quantification (LOQ) was 0.01 mg/kg. The average percent recovery found for spiked samples was 80 % for addition levels between 0.01 and 2.0 mg/kg. All recovery values were between 73 and 91 %. Spiked samples were analysed after storage at -20 °C for periods of 9 and 15 months, in order to check for storage effects. Average recoveries were 69 % indicating no major storage effects. Residues of 2,6-dichlorobenzonitrile were found predominantly in the top layer of the soil (0-10 cm) (see Table 2).

Table 2: Test material residues (mg/kg) in the topsoil layer (0-10 cm)

 Time period  Goch-Nierswalde  Eschwege  Goch-Nierswalde  Nottuln
 Application date  08.06.1989  15.06.1989  09.02.1990  10.02.1990
 Before application  <0.01  <0.01  <0.01  <0.01
 After application  5.53  5.57  1.36  2.09
 1 day  5.17**  6.56  1.60  1.77
 3 days  1.98  6.79  0.556  2.37
 1 week  1.22  1.39  20.6  0.846
 2 weeks  0.654  1.58  0.635  1.82
 4 weeks  0.293  0.404  2.68  2.09
 2 months  0.273  0.371  1.02  0.877
 6 months  0.099  0.525  0.186  0.187
 12 months  0.112  0.277  0.122  0.219
 DT50 (in days)  2  19  -***  102
 DT90 (in days)  54  205  -***  337

*based on the dry weight of the soil; **2 days after application; ***no curve could be fitted

The DT50 and DT90 values were determined according to Timme (1986); only for the second year Goch-Nierswalde, the values did not fit.

Applicant's summary and conclusion

Conclusions:
Under the conditions of this test, the mean DT50 was calculated to be 35 days and the mean DT90 value was 202 days. The theoretical maximum fraction formation of BAM in these field dissipation studies was 12.04 %.
Executive summary:

In a GLP compliant field dissipation study conducted in line with non-standardised guideline BBA Guideline Part IV, 4-1, the DT50 and DT90 values of the test material were determined. Under the conditions of the test, the DT50 was calculated to be 35 days and the mean DT90 value to be 202 days. The theoretical maximum fraction formation of the major metabolite in these field dissipation studies was 12.04 %.