FATE EVALUATION: 1,2,4-Triazole - Revision to DT50s ... · Web viewTriazole Derived Metabolite:...

Commission Regulation 1107/2009

Triazole Derived Metabolite:

1,2,4-Triazole

Proposed revision to DT50

Summary, Scientific Evaluation and Assessment

July 2011, revised September 2011 (after comments from MS and EFSA) and further revised January 2013 (minor

clarifications added post-commenting)

1,2 4-Triazole– Revision of DT50 July 2011 (revised September 2011)

CONTENTS Page

Background 3

B.8 Environmental fate and behaviour 3B.8.1 Route and rate of degradation in soil 3B.8.1.1 Aerobic and anaerobic studies 3B.8.1.3 Field Dissipation studies 21B.8.10 References relied 68Appendix 1: List of endpoints June 2011 70Appendix 2 : Copy of endpoints agreed at PRAPeR 12 meeting of 15 – 18 January 2007

72

2


Background and summary

A number of the triazole fungicides that were evaluated in the 2nd and 3rd stages of the review programme (as referred to in Article 8(2) of Council Directive 91/414/EEC) have metabolites in common. These metabolites (triazole alanine, triazole acetic acid and 1,2,4-triazole) are collectively known as the ‘Triazole Derivative Metabolites’. A group of Notifiers of triazole fungicides have formed a task force called the Triazole Derivative Metabolite Group (TDMG) to produce a common data package to cover the risk assessment for these metabolites. The UK is acting as RMS for a number of parent triazole active substances, and also for the evaluation of a number of metabolite assessments.

This document presents a kinetic re-evaluation of previously submitted laboratory degradation data on the 1,2,4-triazole metabolite using the principles of the FOCUS Degradation Kinetics Guidance. In addition, the TDMG has generated field dissipation data to supplement the re-assessment of the laboratory data. The endpoints derived are presented in Appendix I.

Fate and behaviour endpoints for 1,2,4-triazole were previously discussed and agreed at the PRAPeR 12 meeting of 15 – 18 January 2007. The endpoints agreed at PRAPeR 12 are presented in Appendix II.

CRD proposes that the revised endpoints for metabolite 1,2,4-triazole are agreed by Member States, and then MS should use these endpoints in the re-registration assessments of the triazole fungicide group of parent active substances.

Note that the assessment of July 2011 (version 1) was amended in September 2011 (version 2) after comments from MS and EFSA, and again in January 2013 to provide further clarity of information (FINAL version 3). These latter amendments do not result in a change in the assessment or endpoints from those in version 2 and all changes are highlighted in turquoise.

B.8 ENVIRONMENTAL FATE AND BEHAVIOUR

B.8.1 Route and rate of degradation in soil (IIA 7.1.1, IIIA 9.1.1)

B.8.1.1 Aerobic and anaerobic studies (II 7.1.1, IIIA 9.1.1)

B.8.1.1.2 Soil rate of degradation studies - laboratory

The study subject to re-evaluation is that of Slangen 2000 which was presented in the DARs of a number of triazole fungicide a.s. which have subsequently been listed on Annex I of Directive 91/414/EEC. For completeness, the previous UK evaluation of this study has been re-presented below (in italics) to aid the consideration of the re-assessment.

i) The degradation of metabolite 1,2,4-triazole under aerobic conditions was investigated according to SETAC (1995), CTB (1995), EPA (Subdivision N, part 162-1, 1982) and BBA (part IV, 4-1, 1986) guidelines and GLP. The study is acceptable.

[3,5-14C] 1,2,4-triazole (radiochemical purity >98%) was applied to three soils at a dose of 0.06 mg/kg of dry soil, based on an assumption of 750 g of fungicide active

3


substance/ha, incorporation in 5 cm of soil and a bulk density of soil of 1.5 g/ml, crop interception of 50 %, 50 mol% of the fungicide is converted to 1,2,4-triazole and that the ratio of the molar mass triazole to parent is 0.25. Portions of 100 g (dry weight) of treated soil were transferred into incubation vessels and adjusted to 40 % of the water holding capacity. The test vessels were connected to a humidified air supply (reduced in CO2 content) and to trapping vessels for volatiles (2-methoxyethanol) and carbon dioxide (2 x NaOH). Monitoring and adjustment of the water content in the soil was performed regularly. Temperature for the incubation was maintained at 20 ± 2°C under dark conditions (incubation vessels were made from brown glass). Details of the soils are given in Table B.8.1.

Table B.8.1 Soils used in rate of degradation study on 1,2,4-triazole

Identity and provenance

Soil type (USDA)

Texture analysis( % )

Org.C

(% )

Water holding capacity

pH(CaCl2)

Microbial biomass

sand silt clay (g /100 g) (mg C/kg soil)

LaacherhofAXXa Germany

sandy loam

72.4 22.6 5.0 1.4 34.4 6.4 init.:334end: 198

BBA2.2 Hanhofen,

Germany

loamy sand

78.9 14.4 6.7 2.2 50.0 5.8 init.:294end: 138

LaacherhofAIII Germany

silt loam 36.9 51.1 12.0 0.98 36.4 6.7 init.:252end: 138

At each sample time, a single metabolism vessel with its traps was removed from the incubation system for analysis. Soil samples were extracted with methanol, methanol/water (x2) and finally with methanol under reflux conditions. After each extraction step residues were separated by centrifugation and volume and radioactivity of supernatants were determined. Analysis of extracts was performed by TLC combined with radiography scanning. The identity of metabolites and triazole was ascertained by co-chromatography with reference substances on selected samples. Residual radioactivity remaining in soil samples after extraction was determined by combustion in an oxidizer followed by LSC of the trapped carbon dioxide.

The sodium hydroxide traps were weighed and their radioactivity determined in an aliquot by LSC. The identity of the radioactivity as 14C-CO2 was confirmed by precipitation as barium carbonate in the solutions from the first trap of the samples from day 120. Volatiles others than carbon dioxide were estimated by determining the weight of the 2-methoxyethanol and measuring its radioactivity in an aliquot.

Results are presented in Tables B.8.2 – 4. Degradation rates calculated according to non-linear first order kinetics are presented in Table B.8.5. It should be noted that only data for the first 14 days of the incubation with the BBA 2.2 soil were used in the calculation. The absence of decline in residues of 1,2,4-triazole from day 30 onwards was considered by the study authors as being attributable to ‘reduced bioavailability’ and reduced microbial viability of the soil.

4


Table B.8.2 Results of aerobic soil incubation of 1,2,4-triazole in Laacherhof AXXa soil (% AR)

1,2,4-triazole total extracts

1,2,4-triazole shaking extracts

TAA shaking extracts

Dihydro-triazolone shaking extracts

CO2 Extr Unextr Mass balance

day 0 92.79 83.33 *) 93.72 7.50 101.22day 0 89.18 81.53 89.18 9.60 98.78day 1 61.84 55.33 2.95 0.04 65.56 31.27 96.87day 3 37.39 30.68 4.75 0.39 42.13 58.40 100.92day 7 30.82 23.83 6.30 0.89 37.12 56.14 94.15day 14

25.76 19.11 6.93 0.61 7.38 33.31 51.59 92.27

day 14

29.58 22.03 5.58 5.70 35.16 60.82 101.68

day 30

19.83 16.35 1.29 0.52 5.34 22.15 71.86 99.34

day 61

12.49 9.77 0.55 1.03 12.53 14.60 74.64 101.78

day120 11.99 7.75 19.63 11.99 63.21 94.83day120 11.94 8.18 11.10 11.94 66.16 89.20*) Additionally one unknown with a maximum amount of 0.93 % found for day 0

Table B.8.3 Results of aerobic soil incubation of 1,2,4-triazole in BBA 2.2 Hanhofen soil (% AR)






day 0 90.45 80.39 **) 90.45 8.98 99.43day 0 89.39 80.25 89.39 11.19 100.58day 1 76.15 58.80 0.01 76.15 24.31 100.47day 3 52.44 43.09 0.10 52.44 44.01 96.55day 7 45.68 34.47 0.13 45.68 49.73 95.55day 14

39.35 29.26 1.31 0.28 40.67 51.53 92.48

day 14

39.86 27.70 1.67 0.31 41.53 53.07 94.92

day 30

31.84 20.50 0.42 0.49 32.59 69.80 102.87

day 61

30.24 21.13 0.91 0.98 31.75 65.45 98.18

day120 32.12 21.00 1.42 32.12 54.13 87.67day120 29.85 21.22 1.58 29.85 65.01 96.44**) Additionally one unknown with a maximum amount of 0.63 % found for day 63

5


Table B.8.4 Results of aerobic soil incubation of 1,2,4-triazole in Laacherhof AIII soil (% AR)






day 0 85.21 75.14 ***) 85.21 16.87 102.08day 0 84.70 75.56 84.70 13.22 97.92day 1 75.38 62.36 0.1 75.38 24.72 100.20day 3 50.92 46.66 0.57 50.92 44.19 95.68day 7 45.24 41.85 1.84 45.24 49.38 96.45day 14

37.45 32.67 2.61 0.28 40.06 47.74 88.07

day 14

38.74 32.40 1.85 1.25 40.59 49.31 91.15

day 30

18.29 16.41 0.27 2.22 19.42 20.99 61.64 102.0

day 61

6.58 5.52 1.50 19.65 8.08 49.90 77.62

day 83

3.74 3.56 24.65 3.74 59.33 87.53

day120 1.73 1.32 33.70 1.73 38.47 73.90day120 2.39 1.61 32.22 2.39 41.79 76.40***) Additionally one unknown with a maximum amount of 0.19 % found for day 30

Table B.8.5 Degradation 1,2,4-triazole in three different soils under laboratory conditions (20˚C, 40% MWHC).

Soil Soil type Organic carbon

DT50 values1st order, non-

linearone compartment

r2

Laacherhof AXXa

sandy loam 1.4 % 6.32 days 0.75

BBA 2.2 loamy sand 2.19 % 9.91 days*) 0.81Laacherhof A III silt loam 0.98 % 12.27 days 0.95

Arithmetic mean 9.5 days*) Only 0-14 day data used for calculation.

The degradation rates calculated by the notifier have been confirmed as being acceptable by the Rapporteur.

(Slangen 2000)

Note that the final sentence relating to the kinetic calculations was in relation to the evaluation which was originally conducted prior to adoption of the FOCUS Degradation Kinetics Guidance Document.

6


The TDMG have now provided an updated kinetic assessment of the Slangen 2000 study.

ii) The following assessment relates to re-evaluation of the Slangen 2000 study results according to FOCUS Degradation Kinetics guidance. As such, there is no requirement for this evaluation to comply with GLP as it comprises mathematical modelling, but the study appears to have been conducted appropriately.

The applicant used the KinGUI 1.1 software with MatLab v 7.0.4.365 to perform the modelling analysis and statistical evaluation of kinetic fits. As the original data (see tables B.8.2 – 4) only had data from single replicate samples except for days 0 and 14, the two replicate data points from each of days 0 and 14 were averaged to give a single data point for each of these two sample times in the kinetic analysis. The fitting procedure started by free-fitting SFO to each data set. If the free-fitting approach was considered unacceptable, the fitting procedure was repeated but fixing the initial concentration. Following the SFO steps (free-fitting and fixed initial concentration), bi-phasic kinetics were considered. As the establishment of modelling parameters for 1,2,4-triazole was under consideration, HS and DFOP were tested for the Laacher Hof AXXa and BBA 2.2 datasets as the final concentrations were >10% and FOMC was used to model the Laacher Hof AIII dataset as final concentration was <10%. The data used in the fitting procedure is shown in Table B.8 6. It is noted that the FOCUS Degradation Kinetics guidance indicates that where concentrations do not reach 10% of the initial concentration at study end then HS or DFOP kinetics should be used. The study author has used both HS and DFOP for these soils. In addition, as DFOP appeared to represent the better kinetic for the Laacher Hof AXXa and BBA 2.2 soils, the Laacher Hof AIII dataset was also subject to analysis using DFOP kinetics to determine whether the endpoints from the database of three soils could be expressed by a single consistent kinetic.

Table B.8.6 1,2,4-triazole metabolite data used in fitting (taken from Slangen 2000, % AR)

Laacher Hof AXXa

BBA 2.2 Laacher Hof AIII

DAA Residues %

0 90.99 89.92 84.961 61.84 76.15 75.383 37.39 52.44 50.927 30.82 45.68 45.2414 27.67 39.60 38.0930 19.83 31.84 18.2961 12.49 30.24 6.5883 Not determined Not determined 3.74120 11.96 30.99 2.06

7


In terms of initial concentration used in the fitting procedure, the mass balance at day 0 was used as there were significant unextracted residues (10 – 15% AR) by the time that the day zero sample was taken after dosing. Radiochemical purity of the test compound was also >98% indicating that radiolabelled impurities would be insignificant at this initial sample time; this is confirmed by the information on the extracted fraction which virtually completely comprised 1,2,4-triazole. Correction of the day 0 residue to account for unextracted residues etc. is appropriate and in accordance with FOCUS Kinetics guidance (see section 6.1.6 of the Kinetics guidance). Fitting was unconstrained except for attempts to achieve an acceptable fit with SFO kinetics where the initial concentration was constrained. As these attempts did not result in acceptable fit, results of SFO fit with constrained initial concentration have not been shown. The results obtained for all three soils are collated below.

Table B.8.7 Statistical results of the Applicant kinetic fits for 1,2,4-triazole in three laboratory soils: DT50 and DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.

Vis

ual

rank

ing

Res

id. f

it

Model DT50 / DT50-fast

DT90 / DT50-slow

χ2 test error

T-test k1

T-test k2

Other

[d]Laacher Hof AXXa

SFO 4.7 15.6 -- -- 29.7 0.028

HS 1.9 59.2 ++ ++ 8.5 <0.001 0.03 Tb: 3.2447 (T-test tb: 0.030)

DFOP 0.9 59.2 ++ ++ 5.1 0.001 0.006 “g”: 0.683 (P= <0.001)

BBA 2.2

SFO 40.9 136.2 -- -- 26.4 0.061

HS 3.2 203.9 + ++ 6.2 <0.001 0.047 Tb: 4.0139 (T-test tb: NA)

DFOP 1.5 247.6 ++ ++ 5.1 0.004 0.065 “g”: 0.580 P= <0.001)

Laacher Hof AIII

SFO 9.9 33.0 - - 19.3 0.003

FOMC 22.1 (from DT90) + + 12.3

DFOP 0.8 20.6 ++ ++ 4.5 0.003 <0.001 “g”: 0.443 P= <0.001)

Summary: Geomean all DFOP fits:

DFOP 1.0 d 67.1 d “g”: 0.5691

1 = arithmetic mean

The Applicants assessments for each individual soil are shown below in Table B.8.8 - 10 and Figures B.8.1 – 9. Note that for visual and residual assessment, the following key is used:++ = Very good; + = Good; - = Marginal; - - = Poor

8


Laacher Hof AXXa

Table B.8.8 Statistical results of the Applicant kinetic fits for Laacher Hof AXXa soil: DT50 and DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.

Kinetics DT50 DT90 Visual ranking

Resids fit

χ2 test error

T-test k

SFO 4.7 15.6 - - - - 29.7 0.028Kinetics DT50

-fastDT50-slow

Tb Visual ranking

Resids fit

χ2 test error

T-test k1

T-test k2

T-test tb

HS 1.9 59.2 3.2447 ++ ++ 8.5 <0.001 0.03 0.030Kinetics DT50

-fastDT50-slow

g Visual ranking

Resids fit

χ2 test error

T-test k1

T-test k2

T-test g

DFOP 0.9 59.2 0.683 ++ ++ 5.1 0.001 0.006 <0.001

9


Figure B.8.1 Laacher Hof AXXa Applicant SFO visual and residual fits

0 20 40 60 80 100 1200

10

20

30

40

50

60

70

80

90

100

Time

Concentration

Measured & Predicted vs. Time

Parent

0 20 40 60 80 100 120-20

-15

-10

-5

0

5

10

15

20

Time

Residuals

Residual Plot

Parent

10


Figure B.8.2 Laacher Hof AXXa Applicant HS visual and residual fits

0 20 40 60 80 100 1200

10

20

30

40

50

60

70

80

90

100

Time

Concentration


Parent

0 20 40 60 80 100 120-8

-6

-4

-2

0

2

4

6

Time

Residuals

Residual Plot

Parent

11


Figure B.8.3 Laacher Hof AXXa Applicant DFOP visual and residual fits

0 20 40 60 80 100 1200

10

20

30

40

50

60

70

80

90

100

Time

Concentration


Parent

0 20 40 60 80 100 120-4

-3

-2

-1

0

1

2

3

4

5

Time

Residuals

Residual Plot

Parent

12


BBA 2.2

Table B.8.9 Statistical results of the Applicant kinetic fits for BBA 2.2 soil: DT50 and DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.


Resids fit

χ2 test error

T-test k

SFO 40.9 136.0 - - - - 26.4 0.061Kinetics DT50

-fastDT50-slow

Tb Visual ranking

Resids fit

χ2 test error

T-test k1

T-test k2

T-test tb

HS 3.2 203.9 4.0139 + ++ 6.2 <0.001 0.047 NA a

Kinetics DT50-fast

DT50-slow

g Visual ranking

Resids fit

χ2 test error

T-test k1

T-test k2

T-test g

DFOP 1.5 247.6 0.580 ++ ++ 5.1 0.004 0.065 <0.001a = not available

13


Figure B.8.4 BBA 2.2 Applicant SFO visual and residual fits

0 20 40 60 80 100 1200

10

20

30

40

50

60

70

80

90

100

Time

Concentration


Parent

0 20 40 60 80 100 120-20

-10

0

10

20

30

40

Time

Residuals

Residual Plot

Parent

14


Figure B.8.5 BBA 2.2 Applicant HS visual and residual fits

0 20 40 60 80 100 1200

10

20

30

40

50

60

70

80

90

100

Time

Concentration


Parent

0 20 40 60 80 100 120-6

-4

-2

0

2

4

6

Time

Residuals

Residual Plot

Parent

15


Figure B.8.6 BBA 2.2 Applicant DFOP visual and residual fits

0 20 40 60 80 100 1200

10

20

30

40

50

60

70

80

90

100

Time

Concentration


Parent

0 20 40 60 80 100 120-5

-4

-3

-2

-1

0

1

2

3

4

5

Time

Residuals

Residual Plot

Parent

16


Laacher Hof AIII

Table B.8.10 Statistical results of the Applicant kinetic fits for Laacher Hof AIII soil: DT50 and DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.


Resids fit

χ2 test error

T-test k

SFO 9.9 33.0 - - 19.3 0.003Kinetics DT50 DT90 Visual

rankingResids

fitχ2 test error

FOMC 73.4 + + 12.3Kinetics DT50

-fastDT50-slow

g Visual ranking

Resids fit

χ2 test error

T-test k1

T-test k2

T-test g

DFOP 0.8 20.6 0.443 ++ ++ 4.5 0.003 <0.001 <0.001

17


Figure B.8.7 Laacher Hof AIII Applicant SFO visual and residual fits

0 20 40 60 80 100 1200

10

20

30

40

50

60

70

80

90

100

Time

Concentration


Parent

0 20 40 60 80 100 120-20

-15

-10

-5

0

5

10

15

20

Time

Residuals

Residual Plot

Parent

18


Figure B.8.8 Laacher Hof AIII Applicant FOMC visual and residual fits

0 20 40 60 80 100 1200

10

20

30

40

50

60

70

80

90

100

Time

Concentration


Parent

0 20 40 60 80 100 120-8

-6

-4

-2

0

2

4

6

8

10

12

Time

Residuals

Residual Plot

Parent

19


Figure B.8.9 Laacher Hof AIII Applicant DFOP visual and residual fits

0 20 40 60 80 100 1200

20

40

60

80

100

120

Time

Concentration


Parent

0 20 40 60 80 100 120-4

-3

-2

-1

0

1

2

3

4

Time

Residuals

Residual Plot

Parent

The Applicant proposed the following DT50 values for use in modelling. It should be noted that the slow phase DFOP values are significantly longer than those agreed at PRAPeR 12.

20


Table B.8.11 Applicant proposed soil degradation DT50 values of 1,2,4-triazole.

Location Model fitted:

“g” DT50-fast[d]

DT50-slow[d]

Laacher Hof AXXa DFOP 0.683 0.9 59.2BBA 2.2 DFOP 0.580 1.5 247.6Laacher Hof AIII DFOP 0.443 0.8 20.6

Geometric mean: 1.0 67.1Arithmetic mean: 0.569

Note that no normalisation for moisture content has been performed. This is considered appropriately conservative for 1,2,4-triazole as a terminal metabolite as normalisation for moisture content will result in faster degradation. However, assuming that under conditions of constant moisture status (40% of water holding capacity) the ‘g’ value will be unchanged and fast and slow phases are equally affected, the RMS has calculated the following corrected DT50 values. Note that the values for BBA 2.2 are unchanged as the moisture content in the study was the same as the FOCUS recommended pF2 value for a loamy sand soil.

Table B.8.11a RMS calculated DT50 values of 1,2,4-triazole corrected for moisture.

Location Model fitted:

“g” Moisture correction

factor

DT50-fast[d]

DT50-slow[d]

Laacher Hof AXXa DFOP 0.683 0.624 0.6 36.9BBA 2.2 DFOP 0.580 1 1.5 247.6Laacher Hof AIII DFOP 0.443 0.531 0.4 10.9

Geometric mean: 0.7 46.4Arithmetic mean: 0.569

The Evaluator agrees with the use of the initial concentration of 100% for all three soils based on the mass balance data from the original study for all three soils. The Evaluator also considers that whilst DFOP would not be normally be used on data sets where the applied substance reached at least 10% of the initial dose within the study, e.g. the data set for the Laacher Hof AIII soil, DFOP is considered the preferred kinetic for all three soils, this being a pragmatic choice for consistent modelling parameters. Overall, the Evaluator agrees with this kinetic assessment of 1,2,4-triazole in laboratory soils.

Chapple 2010a

B.8.1.3 Field studiesField dissipation

i) A field dissipation study was conducted on 1,2,4-triazole in accordance with BBA (Part IV, 4-1, 1986) and SETAC (1995) guidelines and to GLP.

21


The field dissipation study was conducted at four different locations, one each in Germany, UK, Italy and Spain. Details of the sites and soil properties are given in Table B.8.12 - 15. The study author stated that the sites had not been treated with chemicals which could influence the dissipation behaviour of 1,2,4-triazole or interfere with analysis. Site histories were presented, which indicated no apparent application of triazole fungicides in at least the previous three years at the German and Italian site. Site history was not actually available for the UK site although it was acknowledged that the site had been used for field testing of triazole fungicides previously. No history of previous pesticide use was available for the Spanish site. Untreated control plots were sampled at each site to determine background levels of 1,2,4-triazole.

Table B.8.12 Soil characteristics of German field dissipation site

22


Table B.8.13 Soil characteristics of Italy field dissipation site

Table B.8.14 Soil characteristics of UK field dissipation site

23


Table B.8.15 Soil characteristics of Spain field dissipation site

Note: MWHC = maximum water holding capacity; organic matter content calculated from % organic carbon x 1.724

At all sites, a single application of 100 g 1,2,4-triazole/ha was applied to bare soil plots which had been pre-prepared to have a fine crumb structure. Following application, grass seed was sown on the bare soil plots at all sites except the Spanish site. The staff conducting the Spanish site considered that given the time of year of application, i.e. June, and the prevailing drought conditions at the time of application, there was no prospect of grass emergence, and so no grass seed was sown at this site. The study author noted that the substance was incorporated almost immediately after application to a depth of 8cm by the grass seed sowing operation. Accuracy of application was checked using filter papers laid on the soil surface. Control plots were also left unsprayed to check for any background levels of 1,2,4-triazole.

Meteorological data were available for all four sites. For the German site, a weather station was available at the test location. For the Italian site, the weather station was located 200 m away from the site. For the UK, weather data was available for a weather station 32km away. For the Spanish site, weather data were available from a site 2.7 km away. Full daily weather data were not presented in the report, but meteorological data at selected dates and total precipitation and monthly mean temperature were available. Total precipitation and range of monthly mean temperature are presented with results of the residues for the individual sites in Tables B.8.20 – 23. It should be noted that daily resolution weather data were provided in another report (Chapple 2010b) detailing normalisation of field dissipation data.

Soil sampling was conducted before and immediately after application at all sites. Day 0 samples were taken to a depth of 10cm (50 mm diameter, 40 cores per sample). On 11 subsequent occasions up to 454 days after application, samples were taken down to a maximum of 50cm depth. Dates and depths of samples are given in the following

24


results tables. Note that the Italian study was terminated at day 180 as the site became no longer available.

Soil samples were deep frozen within 24 hours and stored frozen at -18ºC or below until preparation for analysis. Prior to analysis, cores were divided into 10cm segments and the sample from the appropriate segment homogenised. 15 g subsamples of the homogenised soil were then extracted with acetonitrile/water (6:4 v/v) at 65-70ºC for one hour. Following centrifugation, an aliquot of the extract was derivitised using dansyl chloride in acetone and aqueous sodium sulphate to form dansyl triazole; derivitisation was stated to have been performed to enable analysis to be performed using a non-polar HPLC system and to allow production of more transitional ions in mass spectrometric analysis, aiding sensitivity and detection. Following addition of ammonium hydroxide solution, the derivatives were partitioned into ethyl acetate and dried with anhydrous sodium sulphate. The study author stated that possible matrix effects on the determination of dansyl triazole were eliminated by the use of an internal standard solution of a mixture of isotopically labelled reference items added to an aliquot of the extract. Extracts were concentrated to dryness and reconstituted in acetonitrile/water (1:1 v/v). Following filtering, the extracts were analysed by HPLC-MS/MS. The claimed LOQ was 3 µg/kg for each of the four test sites, and LOD was set at 1 µg/kg. Procedural recovery at the claimed LOQ was in the range 67 – 118% with a mean of 94%. Filter papers from day 0 application checks were also extracted and analysed in a similar method. Procedural recovery at a fortified level of 0.1 µg/cm2 was in the range 75 – 101% with a mean of 89%.

In the context of the day 0 samples, the LOQ of 3 µg/kg represents:

Germany 4.9 – 5.9% of day 0 sample concentrationsItaly 6.0 – 8.6% of day 0 sample concentrationsUK 6.9 – 7.3% of day 0 sample concentrationsSpain 6.6 – 9.7% of day 0 sample concentrations

Representative chromatograms were presented for this study, which demonstrated good separation of peaks and close agreement of peaks from actual residues and the internal standard.

Further assessment of methods of analysis data are presented in B.8.1.3 iii); in summary, the methods of analysis are considered acceptable.

Results of analysis were presented as both 1,2,4-triazole equivalents in both wet and dry weight of soil, but only dry weight concentrations are presented here, in line with normal practice. Residues below LOQ were treated in the following manner:

Values between LOD and LOQ were set to measured values Values <LOD were set 0.5LOD for samples of the next deeper soil layer in

case the detection had been >LOD for the previous soil layer. The curve was stopped after the first non detect of <LOD if no later value >LOD followed

At day 0, values <LOD in deep horizons were set to 0

This procedure is in line with FOCUS kinetics guidance on treatment of values below LOQ and LOD.

25


The concentrations of 1,2,4-triazole in dry weight soil were also used to calculate g/ha doses in 10cm of soil at individual time points for the purpose of kinetic calculations. The bulk density of soil was assumed to be 1.5 g/cm3 for this calculation. The Evaluator confirms that this conversion is acceptable. The study author used MatLab with KinGUI to fit SFO, FOMC and DFOP kinetics to the experimental data.

Results of residues in µg/kg (dry weight) are shown in Tables B.8.16 – 19, and results converted to g/ha in 10cm soil depth are presented in Tables B.8.20 – 23. Results of filter paper analysis are also shown in Table B.8.15a.

Table B.8.15a Results of filter paper analysis as dose check (1,2,4-triazole)

ng/cm2 mg/m2 g/ha Amount recovered %

Germany 873.9 8.739 87.4 87Italy 901.0 0.010 90.1 90UK 869.9 8.699 87.0 87Spain 804.9 8.049 80.5 81

26


Table B.8.16 Residues of 1,2,4-triazole in German field dissipation study (µg/kg).

27


Table B.8.17 Residues of 1,2,4-triazole in Italian field dissipation study (µg/kg).

28


Table B.8.18 Residues of 1,2,4-triazole in UK field dissipation study (µg/kg).

29


Table B.8.19 Residues of 1,2,4-triazole in Spanish field dissipation study (µg/kg).

30


It is noted that in the Italian, UK and Spanish sites, residues of 1,2,4-triazole were found at day 0 in untreated plots, this being particularly noticeable at the Italian site. Subsequent calculation of g/ha residues and kinetic assessments did not correct residues for the concentrations in the untreated plots. The RMS considers that the non-correction of residues would not significantly influence DT50 values recorded.

Table B.8.20 Residues of 1,2,4-triazole in German field dissipation study (g/ha)

Total Rainfall 1381mm; Mean monthly air temperature range 0 – 18ºC

Table B.8.21 Residues of 1,2,4-triazole in Italian field dissipation study (g/ha)

Total rainfall 431mm; Mean monthly air temperature range 5 – 23ºC

31


Table B.8.22 Residues of 1,2,4-triazole in UK field dissipation study (g/ha)


Table B.8.23 Residues of 1,2,4-triazole in Spanish field dissipation study (g/ha)


Results of the kinetic assessment performed by the applicant are shown in Table B.8.24. Note this is on the basis of data not normalised to standard temperature and moisture conditions. The kinetics selected by the study author as the best fit are highlighted in bold text. Visual and residual fits are shown in Figures B.8.10 – 12 for the German trial, Figures B.8.13 – 15 for the Italian trial, Figures B.8.16 – 18 for the UK trial and Figures B.8.19 – 21 for the Spanish site.

32


Table B.8.24 Results of kinetic assessment on 1,2,4-triazole un-normalised field dissipation data

Location Kinetic Model

DT50 [days]

DT90 [days]

Visual Assess*

Chi2 t-test

Germany

SFO 22.9 75.9 - 24.9 k 0.0037FOMC 7.8

α 0.4454366.7β 2.0966

+ 15.2 -

DFOP 11.3k1 0.1149

241.6k2 0.0051g 0.6602

O 18.5 k1 0.0449k2 0.1137g 7.2x10-4

Italy

SFO 48.8 162.2 O 17.9 k 0.0026FOMC 16.3

α 0.3883>1000β 3.2894

+ 11.3 -

DFOP 21.2k1 0.3500

207.4k2 0.0086g 0.4000

+ 10.7 k1 0.0853k2 0.0060g 0.0018

UK

SFO 21.8 72.3 O 25.4 k 0.0064FOMC 8.1

α 0.5728188.4β 3.4434

+ 20.2 -

DFOP 6.8k1 0.4863

109.3k2 0.0154g 0.4633

+ 17.8 k1 0.0868k2 0.0178g 0.0024

Spain

SFO 85.6 284.4 O 21.8 k 0.0031FOMC 28.6

α 0.3618>1000β 4.9336

+ 12.6 -

DFOP 28.1k1 0.0632

717.6k2 0.0020g 0.5732

+ 13.3 k1 0.0395k2 0.0903g 4.5x10-4

*Visual assessment: + = good O = medium -- = badt-test: SFO, for rate constant; DFOP, for k1, k2 and g; FOMC, t-test not applicable, no confidence intervals for α or β parameters given

Note α and β values for FOMC and k values for DFOP fast and slow phases and associated g values have been added for clarity if these are required for e.g. PECsoil calculation. The DT50 and DT90 values in each case refer to the whole decline curve.

33


Figure B.8.10 SFO visual and residual fits for 1,2,4-triazole at German field dissipation site

34


Figure B.8.11 FOMC visual and residual fits for 1,2,4-triazole at German field dissipation site

Figure B.8.12 DFOP visual and residual fits for 1,2,4-triazole at German field dissipation site

35


Figure B.8.13 SFO visual and residual fits for 1,2,4-triazole at Italian field dissipation site

Figure B.8.14 FOMC visual and residual fits for 1,2,4-triazole at Italian field dissipation site

36


Figure B.8.15 DFOP visual and residual fits for 1,2,4-triazole at Italian field dissipation site

Figure B.8.16 SFO visual and residual fits for 1,2,4-triazole at UK field dissipation site

37


Figure B.8.17 FOMC visual and residual fits for 1,2,4-triazole at UK field dissipation site

Figure B.8.18 DFOP visual and residual fits for 1,2,4-triazole at UK field dissipation site

38


Figure B.8.19 SFO visual and residual fits for 1,2,4-triazole at Spanish field dissipation site

Figure B.8.20 FOMC visual and residual fits for 1,2,4-triazole at Spanish field dissipation site

39


Figure B.8.21 DFOP visual and residual fits for 1,2,4-triazole at Spanish field dissipation site

Based on the good visual fits, the RMS accepts the Applicant choice of best fit kinetics as reported in Table B.8.24 above. However, it should be noted that care should be exercised in the use of these endpoints as they only represent dissipation/disappearance of this substance which has been applied as the starting material. In the real agricultural field situation, formation will be occurring from the parent at the same time as degradation and other dissipation processes which would lead to a longer dissipation rate.

Tarara 2010

ii) A modelling procedure was conducted on the results of the field dissipation studies described in Tarara 2010 to normalise the field dissipation DT50 and DT90 to standard temperature and moisture conditions of 20ºC and pF2. As this was a modelling exercise, GLP is not applicable, but the procedure appeared to have been conducted in an appropriate manner.

The study author investigated the suitability of the field dissipation study data for normalisation to standard temperature and moisture conditions. It was noted that volatilisation may be an important route of loss for 1,2,4-triazole as the substance has a vapour pressure of 3.4 x 10-1 Pa at 25ºC (reported in the DAR for the substance difenoconazole; it is also noted from the DAR for difenoconazole that the Henry’s law constant is calculated to be 3 x 10-5 Pa.m3.mol-1 at 25ºC). In addition, it was noted that soil photolysis may be a potential route of degradation.

40


The study author noted that in three of the four field dissipation sites (i.e. not the Spanish site), the substance was incorporated almost immediately after application to a depth of 8cm by the grass seed sowing operation. Reference to sections 3.3. and Appendix 5 of the Tarara 2010 study demonstrate that whilst grass was not sown at the Spanish site, an incorporation procedure was included at this site. The study author stated that in each study, four samples were taken at day 0, two before incorporation and two after. The study author analysed the day 0 data set for the four sites using ANOVA (analysis of variance) techniques, and whilst finding that the mean difference in residue before and after incorporation was small (mean residue before 46.4, mean residue after 44.9, units not stated but assumed to µg/kg dry weight), the difference was not statistically significant. Difference between sites was significant. From this, they concluded that any effect of volatilisation and photolysis would have been only slight or non-existent. The Evaluator notes that the residues measured at day zero were relatively scattered at all sites, and only at the Spanish site was there much of a difference apparent between the first two and the second two day 0 samples (see Table B.8.20); the magnitude of difference between the pre- and post-incorporation residues is similar to the magnitude of scatter at other sites, suggesting that differences between pre- and post-incorporation residues at the Spanish sites may not be a real reduction in residues over time but a chance arrangement of scattered data. The Evaluator also notes that there were no volatile substances other than CO2 captured in the Slangen 2000 laboratory study on 1,2,4-triazole which adds additional weight to the hypothesis that volatilisation would have been minimal. In addition, whilst the vapour pressure is relatively high, the Henry’s Law constant is relatively low suggesting that volatilisation from moist soil would be relatively low. Overall, the Evaluator concludes that significant losses via volatilisation and/or photolysis would have been minimal.

The study author also noted that plant uptake may also influence the results from this procedure. However, whilst acknowledging that this normalisation procedure did not explicitly take plant uptake into consideration, they stated that any subsequent groundwater modelling should specifically set crop uptake for this metabolite to 0. The Evaluator notes that grass cropping was implemented in the subsequent PEARL procedure to simulate soil temperature and soil moisture, but this procedure did not actually simulate pesticide fate. Thus the study author is correct to make this specific recommendation to avoid crop uptake being double counted in any exposure assessment.

Prior to kinetic fitting, the same pre-processing of raw field dissipation residues data was conducted as performed in the Tarara 2010 study. Consequently the residues data, expressed in g/ha and assumed to be in the top 10cm, and shown in Tables B.8.21 – 24, were used in the analysis. The Evaluator notes that soil residues from 0-30cm and on occasion 0-40cm were used to derive the residues in g/ha. It is also noted that FOCUS leaching models assume that degradation slows at increasing soil depth and thus if this was not taken into consideration in the normalisation procedure for residues reaching depth, there could be an over-estimation of speed of degradation. The general assumption in FOCUS models is that degradation slows by a factor of 0.5 at soil depths of 30-60cm; there is no depth-related reduction in degradation in the 0-30cm layer. In the 1,2,4-triazole residues data set, residues were only infrequently analysed for soil depths of 30-40cm, but these were present below LOD in all instances. On further questioning from the Evaluator, the Applicant stated that 88-98% of residues

41


were found in the 0-10cm layer and considered that any influence of change in temperature, moisture or depth dependent degradation rate would be relatively small over this soil depth. They also demonstrated that normalising the timesteps based on just the top 5cm depth compared to a 30cm depth had a very small impact on the normalised timesteps in the case of these four soils; this is shown in Table B.8.24a. The Evaluator considers that whilst the effect of moisture was not considered in this response, the fact that the majority of the residue was located in the top most layer means that effectively restricting consideration to the top 10cm in this case has little impact on the normalisation procedure.

Table B.8.24a Effect of target soil depth (5 cm v. 30 cm) on timestep calculations for correction of field trial time scale to temperature (20 °C) and soil moisture (pF2)

Germany ItalyDays 5 cm 30 cm Days 5 cm 30 cm

0 0.0 0.0 0 0.0 0.01 0.3 0.3 1 0.8 0.93 0.9 0.9 3 2.9 2.88 3.3 3.1 7 7.3 7.014 5.8 5.6 14 11.9 12.028 12.8 12.4 25 21.9 22.159 31.5 29.7 60 56.4 57.491 58.4 56.2 90 76.5 78.4121 76.0 73.9 118 92.9 94.4185 96.3 94.5 180 112.7 114.7364 136.9 133.9451 190.5 186.8

UK SpainDays 5 cm 30 cm Days 5 cm 30 cm

0 0.0 0.0 0 0.0 0.01 0.3 0.4 1 0.7 0.82 0.7 0.7 3 1.9 2.47 3.4 3.2 8 4.8 5.814 8.1 7.8 16 9.6 10.428 14.0 14.0 28 17.3 18.563 35.1 34.3 64 44.7 45.091 57.0 55.8 93 64.1 63.0135 78.6 77.4 140 81.6 80.9191 98.3 97.1 210 98.9 98.1364 145.6 143.9 330 133.8 133.0454 189.4 186.2 415 192.1 191.0

42


Free-fitting of the data was allowed. The four replicate samples taken at day 0 were averaged due to the variability of the residue values and because it was considered that the four replicates at this single time point compared to the single replicate at other times would inappropriately weight the fit to the day 0 data.

The daily weather data from the local weather stations for the study period were used to derive the .met files for use in PEARL. Whilst the daily resolution weather data are not available in the Tarara 2010 field dissipation study report, the study author for the normalisation procedure has included the daily weather data as an appendix. Soil descriptions were input into PEARL using the available textural information from the Tarara 2010 report. Additional hydraulic parameters were then derived using the ROSETTA software. Soil profiles of 1m depth were described; the profile was discretised at 2.5cm intervals for the first 60cm and then at 5cm intervals for the remaining profile. The three sites where grass was sown had grass implemented as the crop using relevant development stages and leaf area indices taken from the FOCUSgw report.

Using this information, PEARL was run for each soil to generate daily soil temperature and soil moisture information for each of the field dissipation sites. The daily values at 1.25, 3.75, 6.25 and 8.75cm were averaged to give a value for the top 10cm. The daily difference between predicted soil temperature and moisture and the standard conditions, i.e. 20ºC and pF2 were then calculated and used in a time step normalisation procedure to amend the sampling times used in kinetic analysis. Temperature normalisation used a Q10 value of 2.58 as recommended by the EFSA PPR Panel in their opinion of 2007. Moisture normalisation used a Walker exponent of 0.7 as recommended in the FOCUSgw report.

The study author stated that volumetric water contents at pF2 were calculated for each soil. These values (shown below) are different to those quoted in the Tarara 2010 study. However, given that the soil moisture parameters used in PEARL were derived from ROSETTA, it was appropriate that the pF2 values for the simulated soils be calculated from ROSETTA parameters for consistency. This seems to be an acceptable approach in the opinion of the evaluator. In addition, the calculated values are, in most cases, quite close to the measured values (see Tables B.8.12 – 15 for measured values).

Table B.8.25 Calculated pF2 values for field soils

43


Table B.8.26 Calculated timesteps for use in kinetic evaluation

Following calculation of the timesteps, kinetic analysis was undertaken with these new values to derive kinetic parameters for use in modelling. The modelling was undertaken using KinGUI v 1.1 with MatLab v 7.0.4.365. The methodology used generally agreed with principles outlined in the FOCUS Degradation Kinetics guidance document. FOMC kinetics was not attempted for the Italian and Spanish sites because residues at the end of the study were >10% of the day 0 residue However, it is noted that they considered a t-test value of<0.1 to be acceptable for field studies. The Evaluator notes that this is not specifically stated in FOCUS Degradation Kinetics; FOCUS Degradation Kinetics uses a general assumption that t-test values <0.05 can be considered as indicating the parameter is significantly different from zero at a 5% significance level and that values between 0.05 and 0.1 can be considered as acceptable provided that there is further discussion and justification based on fit and weight of evidence. However, the Evaluator can understand the reasons for using this assumption given the general observation that field dissipation data can be more scattered than laboratory data. It is noted that the study author attempted to obtain DFOP kinetic endpoints for each trials site in order to maintain consistency for selection of mean input parameters but also to make use of the bi-exponential approaches for groundwater modelling as detailed in FOCUS Degradation Kinetics guidance. Results of statistics generated from the kinetic analyses are given in Tables B.8.27 – 30, and graphical fits in Figures B.8.22 – 35.

44


Table B.8.27 Statistical results of the Applicant kinetic fits for SFO model to normalised field dissipation data: DT50 and DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.

Table B.8.28 Statistical results of the Applicant kinetic fits for FOMC model to normalised field dissipation data: DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.

Note: t-test is not directly applicable to the α and β parameters; assessment of confidence intervals for both FOMC assessments indicates that the ranges include zero for the β parameter for both sites and therefore may be unreliable

Table B.8.29 Statistical results of the Applicant kinetic fits for Hockey Stick model to normalised field dissipation data: DT50 and DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.

45


Table B.8.30 Statistical results of the Applicant kinetic fits for DFOP model to normalised field dissipation data: DT50 and DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.

Errata: Note that the k1 t-test result for the Vilobi, Spain site above is incorrect, it is actually 0.082.

In every case, the kinetic behaviour observed was bi-phasic rather than SFO. The Evaluator considers that for the UK site that DFOP is a slightly better fit than FOMC. In the case of the Italian and Spanish sites, there seems to be no advantage in choosing DFOP over HS except for the pragmatic choice of consistency and using DFOP in leaching models.

In the study author’s view, the preferred kinetic at the German site was FOMC. In an attempt at obtaining consistency of modelling endpoints conforming to DFOP, a further assessment of the German site was conducted. In this, the initial data point was removed and the DFOP kinetics re-fitted. This resulted in an improved visual and residual fit and improved χ2 error test. However, the applicant considered that removal of the data point could not be justified and thus in a further analysis, the g parameter in the DFOP assessment was fixed at the value of 0.655, i.e. that achieved when the initial data point was removed, but the initial data point was re-instated in the dataset. This improved the visual and residual fits, but resulted in a poorer χ2 error test. The statistical results of this further assessment are shown below.

Table B.8.31 Statistical results of the Applicant kinetic fits for DFOP model to normalised field dissipation data for German site: DT50 and DT90 [d], visual ranking and quality of fits, visual assessment of random-ness of residuals, scaled error ε to pass the 2 test, and T-test for relevant parameter fit.

It is noted that relying solely on the outcome of the statistical evaluation in Table B.8.31 above indicates that the procedure fixing g to 0.655 results in a poorer χ2 value compared to the free fit to the German site dataset but improved t-test for the k1 value. However, whilst the procedure fixing g results in a poorer χ2 value, the visual fit is improved for data points 5 onwards, i.e. from a residue of approx 30 g/ha or 35% of

46


the initial (contrast Figures B.8.29 for free fit and B.8.31 for fixed g). The Evaluator postulates that the reason why χ2 becomes higher in value with fixing of g is that the residuals for the first three data points have become much greater, indicating that the initial data points are fitted less well (indeed, estimated M0 for free fit is 86.96 g/ha vs. 73.60 g/ha for fit with g fixed; actual M0 was 87.5 g/ha). Thus the Evaluator considers that the study author conclusion that the overall fit of the curve was better as a result of fixing ‘g’ to 0.655 is subjective and that the choice of DFOP fits is marginal. Comparisons of k and g values for the two fits with the German site dataset and the difference in overall geometric mean parameters for all 4 soils based on DFOP kinetics are given in Tables B.8.32 and 33.

Table B.8.32 Comparison of DFOP kinetic values for the German field dissipation site with free fitting of g and fixing g

Fast phase DT50

Slow phase DT50

g Estimated M01

Free fit g 0.21 days 30.1 days 0.4687 86.96Fixed g 2.5 days 70.7 days 0.6550 73.601 Actual M0 87.5 g/ha

Table B.8.33 Comparison of geomean modelling parameters from all four field dissipation sites using alternative DFOP parameters from German site

Fast phase DT50

Slow phase DT50

g1

Free fit g 0.91 48.8 0.442Fixed g2 1.68 60.5 0.4891 arithmetic mean 2 study author proposed values

Overall, the Evaluator considers that there is little to choose between the mean parameters. Free fitting of ‘g’ at the German site leads to slightly faster degradation but less substance in the faster degrading compartment, whereas fixed ‘g’ at the German site leads to slightly slower degradation but a higher proportion of substance in the faster degrading compartment. Thus, taking all considerations into account, the Evaluator considers that the study authors choice of parameters based on the fixed g value for the German site is acceptable, particularly if 1,2,4-triazole is the terminal metabolite in the leaching assessment. The final presentation of the study author’s choice of modelling endpoints for 1,2,4-triazole is given below.

47


Table B.8.34 Proposed kinetic endpoints for 1,2,4-triazole for modelling (normalised to 20°C and pF2)

aThe proportion of the substance described by k1. bFixed to 0.655. cArith. mean

48


Germany

Figure B.8.22 SFO visual and residual fits for 1,2,4-triazole at German field dissipation site, timestep normalised

49


Figure B.8.23 FOMC visual and residual fits for 1,2,4-triazole at German field dissipation site, timestep normalised

50


Figure B.8.24 DFOP visual and residual fits for 1,2,4-triazole at German field dissipation site, timestep normalised

51


Figure B.8.25 DFOP visual and residual fits for 1,2,4-triazole at German field dissipation site, timestep normalised, initial data point removed

52


Figure B.8.26 DFOP visual and residual fits for 1,2,4-triazole at German field dissipation site, timestep normalised, initial data point included, ‘g’ fixed at 0.655

53


Italy

Figure B.8.27 SFO visual and residual fits for 1,2,4-triazole at Italian field dissipation site, timestep normalised

54


Figure B.8.28 HS visual and residual fits for 1,2,4-triazole at Italian field dissipation site, timestep normalised

55


Figure B.8.29 DFOP visual and residual fits for 1,2,4-triazole at Italian field dissipation site, timestep normalised

56


UK

Figure B.8.30 SFO visual and residual fits for 1,2,4-triazole at UK field dissipation site, timestep normalised

57


Figure B.8.31 FOMC visual and residual fits for 1,2,4-triazole at UK field dissipation site, timestep normalised

58


Figure B.8.32 DFOP visual and residual fits for 1,2,4-triazole at UK field dissipation site, timestep normalised

59


Spain

Figure B.8.33 SFO visual and residual fits for 1,2,4-triazole at Spanish field dissipation site, timestep normalised

60


Figure B.8.34 HS visual and residual fits for 1,2,4-triazole at Spanish field dissipation site, timestep normalised

61


Figure B.8.35 DFOP visual and residual fits for 1,2,4-triazole at Spanish field dissipation site, timestep normalised

Chapple 2010b

Evaluator’s final note: The geomean slow phase DT50 from this evaluation is in reasonable agreement with that from the kinetic assessment of the laboratory studies. Overall, it is considered that the laboratory and the field data give strong support for 1,2,4-triazole demonstrating bi-phasic degradation. If 1,2,4-triazole is being considered as a terminal metabolite in a leaching assessment, it is appropriate to simulate degradation of this metabolite using two compartments, one for the rapid degradation phase and the other the slow degradation phase. The separate flows from

62


the precursor to the rapid and slow phases should be specified along a similar scheme as shown in chapter 8.3.3.2.2 and Box 8-2 of the FOCUS Degradation Kinetics guidance. Specifically, the proportion of flow to the rapid phase of degradation would be specified by ffM x g (i.e. formation fraction for precursor to 1,2,4-triazole multiplied by the DFOP ‘g’ parameter) and the proportion of flow from precursor to the slow phase would be specified by ffM x (1-g) (i.e. formation fraction for precursor to 1,2,4-triazole multiplied by 1-‘g’). Given that this method divides the formation fraction for the metabolite between fast and slowly degrading compartments using the ‘g’ parameter as part of the simulation, it is considered unnecessary to run the model twice as specified in FOCUS degradation kinetics (i.e. it is unnecessary to run the fast and slow compartments separately and add the results together). However, due to the 1/n value for 1,2,4-triazole being less than 1, the recommendation that the application rate in the simulation is doubled and the resulting leaching concentrations divided by 2 is supported.

Note that no PEC calculations are considered in this evaluation document as the concentrations of 1,2,4-triazole will be dependent on the amount of formation from each separate triazole parent a.s. and the GAP details for the parent.

iii) An assessment of freezer storage stability and analytical methods in support of these data is given below.

Freezer Storage Stability of lH-l,2,4-Triazole[3,5-14C] in Soil; (report no. 108303)

Samples of loamy sand soil from a site in Fresno, California, USA were fortified with [14C]-1, 2, 4-triazole at a concentration of 10.3 mg/kg and stored frozen at -25°C for up to 42 months. Duplicate samples were removed from the freezer and analysed for residues of 1, 2, 4-triazole at day 0 and after 1, 3, 6, 12, 21 and 42 months storage. A “control” sample, freshly fortified was also analysed at each time point

Analysis for residues of 1, 2, 4-triazole was conducted as follows:

Samples were extracted for 1 hour at room temperature (by magnetic stirrer) with methanol: water 4:1 (v/v) and centrifuged. The supernatant was decanted. The samples were then extracted for 30 minutes with two aliquots of methanol and centrifuged. Finally the samples were extracted for 2 hours with methanol: ammonium hydroxide (aq) 7:3 (v/v) and centrifuged.

Radioactive residues were determined by LSC or LSC following combustion in the case of the post extraction solids. Aliquots of the extracts were filtered, concentrated under a stream of oxygen free nitrogen and analysed by TLC against certified reference standards. Further analyte confirmation was conducted by LC-MS (ESI mode). The results are shown below:

The Evaluator considers that the results indicate that residues of 1, 2, 4-triazole are stable in samples of loamy sand soil stored frozen for up to 42 months.

63


Table B.8.35: Radioactive residues in samples of soil stored frozen for up to 42 months

64


Table B.8.36: Residues of 1,2,4 – triazole samples of soil stored frozen for up to 42 months of soil

Shadrick et al, 1999

65


Analytical method JA005-W04-01 was used in field dissipation studies. The method utilises derivation of 1, 2, 4-triaozle with dansyl chloride to give dansyl-1, 2, 4-triazole. The following justification for using a derivatisation method was provided:

“Derivatisation allowed triazole to be run in a non-polar HPLC system, similar to other fungicide metabolites. Also, derivatisation provided larger mass; therefore more transitional ions within the mass spectrometer environment, which aided sensitivity and detection.”

This is considered acceptable by the Evaluator.

Analytical Method for the Determination of Triazole in Soil and Sediment; Method JA005-W04-01

Samples of soil were extracted by ultrasonication for 1 hour with acetonitrile: water 6:4 (v/v) at 65-70°C. Samples of sediment were extracted in the same manner but using 1% sodium hydroxide: acetonitrile 6:4 (v/v). A 1ml aliquot of the extract was taken and derivatised with dansyl chloride to give dansyl 1, 2, 4-triazole. The derivatised extract was partitioned with ethyl acetate, filtered through anhydrous sodium sulphate, concentrated to dryness and reconstituted in acetonitrile: water 1:1 (v/v). Extracts were analysed by LC/MS/MS in positive ionisation mode; luna C13 column, 100 x 4.6mm, 5 µm i.d. Stable isotope [15N]-1, 2, 4-triazole was used as an internal standard by addition to the extract prior to derivatisation. Quantitative analysis was performed using reference standards of dansyl 1, 2, 4-triazole and stable isotope [15N]-dansyl 1, 2, 4-triazole. The ion transitions monitored were 303→170 for dansyl 1, 2, 4-triazole and 306→170 for the stable isotope internal standard. Results were expressed in terms of 1, 2, 4-triazole.

The LOQ was stated to be 10µg/kg. Validation data were provided using soil from Saskatchewan, Canada as follows:

Linearity: demonstrated in the range 2.5 – 100 ng/ml (equivalent to 5 – 200 µg/kg in the samples). R2 > 0.99.

Precision: 7 determinations made at 10µg/kg. RSD = 1.84%. 5 determinations made at 100 ppb. RSD = 2.29%

Accuracy: Mean recovery values at fortification levels of 10µg/kg and 100 µg/kg for several different soil types were in the range 79-105%. Further details are given in the table below:

66


Table B.8.37 Average recoveries of 1,2,4-traiazole in soils

The Evaluator considers that the method is suitably validated/fit for purpose.

I. M. Murphy, 2004

Determination of the Residues of 1,2,4-Triazole in/on soil after spraying of 1,2,4-Triazole (1000 TS) in the field in Germany, Italy, Great Britain and Spain Analytical Phase; report PF/04/004.

Samples were analysed according to the method JA005-W04-01 above. The filter paper samples were extracted in the same way as the soil samples but extracts were diluted by 1:20 with acetonitrile: water 6:4 (v/v) before an aliquot was taken for derivatisation.

The LOQ was stated to be 3µg/kg for soil and 0.1µg/cm2 for filter papers.

A separate validation study for the method was provided (S Jones 2005. Report CX/05/035). The results are summarised in the table below

67


Table B.8.38 Validation of Analytical Method for the Determination of 1,2,4-Triazole in Soil and Filter Papers.

Matrix Method Analyte LOQ (µg/kg)

Recovery fortification level(µg/kg)

Recoveries % range (mean*)

Repeatability% RSD (n)

Linearity

SoilHPLC–MS/MS

Dansyl 1,2,4-triazole

3.0

3.0

30

65-100(82.6)

64-79(72.0)

11.7(12)

4.7(12) 0.75-100

ng/mlr2 = 0.9996

Filter paper

HPLC–MS/MS

Dansyl 1,2,4-triaozle

0.1 µg/cm2

0.1 µg/cm2

1.0 µg/cm2

75-101 (89)

80-89 (83)

10.9 (6)

Some of the control samples used for fortification had apparent residues at levels >30% of the LOQ – recoveries were corrected to take these residues into account. The potential residues in the blank samples may explain the variable recoveries. Whilst some individual recoveries are outside of the range 70-110%, the mean recoveries are within the acceptable range and the precision (repeatability) is acceptable. It has been demonstrated that the derivative is formed reproducibly by the use of an external standard of the derivate. The method is considered suitably validated.

Further procedural recoveries in the soil at fortification levels of 3µg/kg were in the range 67-118% with a mean of 94% and for a fortification level of 100µg/kg were in the range 70-80% with a mean of 75%. These are considered acceptable by the Evaluator.

S Jones 2005; M Fitzmaurice 2010

68


B.8.10 References relied on

Annexpoint

Author Year TitleSource (where different from company)Company, Report No.GLP or GEP status (where relevant)Published or Unpublished

Data protection claimed Y/N

Owner

B.8.1.1.2 Slangen, P.J. 2000 Degradation of 1,2,4-triazole in three soils under aerobic conditionsNOTOX Safety & Environmental Research B.V., 's-Hertogenbosch, NetherlandsBayer CropScience AG,Report No.: 278336, Date: 2000-05-08GLP, unpublished

Yes TDMG

B.8.1.1.2 Chapple, A. 2010a Kinetic evaluation of the degradation in soil of 1,2,4-triazole under laboratory conditionsBayer CropScience AGReport No. MEF-10/556Date: 2011-02-09Non-GLP, unpublished

Yes TDMG

B.8.1.3 Tarara, G. 2010 Determination of the residues of 1,2,4-triazole in/on soil after spraying of 1,2,4-tiazole (1000 xx) in the field in Germany, Italy, Great Britain and SpainBayer CropScience AGReport No.: RA-2145/04Date: 2010-03-04GLP, unpublished

Yes TDMG

B.8.1.3 Chapple, A. 2010b Kinetic evaluation of the dissipation in soil of 1,2,4-triazole under field conditionsBayer CropScience AGReport No.: MEF-10/069Date: 2010-03-17Non-GLP, unpublished

Yes TDMG

B.8.1.3 Shadrick, B.A; Bloomberg, A.M; Helfrich, K.K.

1999 Freezer storage stability of 1H-1,2,4-triazole [3,5-14C] in soilBayer CropScience AGReport No.: 108303Date: 1999-12-22GLP, unpublished

Yes TDMG

B.8.1.3 Murphy, I.M. 2004 Analytical method for the determination of triazole in soil and sedimentBayer CropScience AGReport No. 200516Method No. JA005-W04-01Date: 2004-02-20GLP, unpublished

Yes TDMG

69


Annexpoint

Author Year TitleSource (where different from company)Company, Report No.GLP or GEP status (where relevant)Published or Unpublished

Data protection claimed Y/N

Owner

B.8.1.3 Jones, S. 2005 Validation of analytical method for the determination of triazole in soil and filter papersBattelle UK Ltd, Ongar, Essex, UKBayer CropScience AGDate: 2005-06-20GLP, unpublished

Yes TDMG

B.8.1.3 Fitzmaurice, M. 2010 Determination of the residues of 1,2,4-triazole in/on soil after spraying of 1,2,4-triazole (1000 TS) in the field in Germany, Italy, Great Britain and Spain, analytical phaseBattelle UK Ltd, Ongar, Essex, UKBayer CropScience AGDate: 2010-02-23GLP, unpublished

Yes TDMG

70

1,2 4-Triazole– Revision of DT50 – APPENDIX I July 2011

List of end points (based on EPCO Manual E4 - rev. 4 (September 2005))Rapporteur Member State

Month and year Active Substance (Name)

United Kingdom July 2011 1,2 4-Triazole

Fate and behaviour in the environment

Appendix I – List of end points July 2011

Rate of degradation in soil (Annex IIA, point 7.1.1.2, Annex IIIA, point 9.1.1)

Laboratory studies – modelling kinetic parameters

1,2,4-triazole (applied as parent)

Aerobic conditions

Soil type X1 pH t. oC / % MWHC

DT50 fast phase/DT50

slow phase(d)/g

DT50 (d)

20C pF2/10kPa

St.

(r2)

Method of calculation

Sandy loam 6.4 20 oC / 40 % 0.9/59.2/ 0.683

DFOP

Loamy sand 5.8 20 oC / 40 % 1.5/247.6/0.580

DFOP

Silt loam 6.7 20 oC / 40 % 0.8/20.6/ 0.443

DFOP

Geometric mean/median 1.0/67.1/ 0.569

DFOP

Field studies ‡


Aerobic conditions, kinetics calculated for ambient conditions. Bare soil with grass sown immediately after application (with exception of Spain site where no grass sown).

Soil type (indicate if bare or cropped soil was used).

Location (country or USA state).

X1 pH Depth (cm)

DT50 (d)

actual

DT90(d)

actual

St.

(χ2)

DT50 (d)

Norm.


Silt loam Germany 6.4 0-30 7.8 366.7 15.2 FOMC

Silty clay loam Italy 7.6 0-40 21.2 207.4 10.7 DFOP

Sandy loam UK 7.4 0-40 6.8 109.3 17.8 DFOP

Loam Spain 5.8 0-30 28.1 717.6 13.3 DFOP

1 X This column is reserved for any other property that is considered to have a particular impact on the degradation rate.

71

1,2 4-Triazole– Revision of DT50 – APPENDIX I July 2011



United Kingdom July 2011 1,2 4-Triazole


Geometric mean/median


Aerobic conditions, kinetics calculated timestep normalised to 20ºC and pF2 moisture. Bare soil with grass sown immediately after application (with exception of Spain site where no grass sown).

Soil type Location pH Depth (cm)

DT50 (d)

Fast phase

DT50 (d)

Slow phase

‘g’ St.

(χ2)


Silt loam Germany 6.4 0-30 2.5 70.7 0.655

18.8 DFOP

Silty clay loam Italy 7.6 0-40 1.4 59.8 0.364

10.6 DFOP

Sandy loam UK 7.4 0-40 0.5 25.1 0.458

18.1 DFOP

Loam Spain 5.8 0-30 4.6 126.0 0.489

12.7 DFOP

Geometric mean (‘g’ value is arithmetic mean) 1.68 60.5 0.489

DFOP

Repeat for as many metabolites as necessary

pH dependence ‡(yes / no) (if yes type of dependence)

No

72

1,2 4-Triazole– Revision of DT50 - APPENDIX II July 2011



EFSA January 2007 Triazole fungicides and their metabolites


Appendix 2 – copy of endpoints agreed at PRAPeR 12 meeting of 15 – 18 January 2007

Route of degradation (aerobic) in soil (Annex IIA, point 7.1.1.1.1)

Mineralization after 100 days ‡ Bitertanol1,2,4-triazole1.6-52% after 90-120 days triazole label (n=6)

Epoxiconazole- Metabolite [3,5-14C] 1,2,4-triazole:Study duration 360 days, (CO2 % TAR)soil 1, pre-adapted 24 % after 90 days

39.1 % after 180 dayssoil 2, pre-adapted 51.6 % CO2 after 90 days soil 3, non-adapted: 15/14 % CO2 after 90 days

- Metabolite [3,5-14C] 1,2,4-triazole, rate study:Sandy loam 20/11 % CO2 after 120 days (study end)Loamy sand: 1.4/1.6 % CO2 after 120 days (study end)Silt loam: 34/32 % CO2 after 120 days (study end)

Triadimenol1,2,4-triazole

1.6-52% after 90-120 days triazole label (n=6)

Agreed End Point (PRAPeR 12)

Non-extractable residues after 100 days ‡ Bitertanol

1,2,4-triazole38-67% after 90-120 days triazole label (n=6)

Epoxiconazole- Metabolite [3,5-14C] 1,2,4-triazole (% TAR):soil 1, pre-adapted - max. 75 % after 28 days, 43 % after 360 d (study end)soil 2, pre-adapted - max. 53.5 % after 28 days,

73






33.7 % after 360 d (study end)Triadimenol1,2,4-triazole 38-67% after 90-120 days triazole label (n=6)Agreed End Point (PRAPeR 12)

Metabolites requiring further consideration ‡- name and/or code, % of applied (range and maximum)

Bitertanol1,2,4-triazole 44% at 62 d (n=1) declining to 36% at study end (120 days)CyproconazoleTriazole ( triazole label), 17.36 % at 140 d (n= 1), max 17.36%, day 140Triazole acetic acid (triazole label), 0-6.7 % at 140 d (n= 1).Bromuconazole1,2,4-triazole is no major metabolite in soil, No end points derived.

Difenoconazole 1, 2, 4-triazole (CGA 71019) max. 20.6-23.4% after 190/271 d [14C-triazole]-label (n=2)

EpoxiconazoleInvestigated: triazole 14C-labelled epoxiconazole (% TAR): Study duration 343 d, only study end data:Loamy sand: 5.0 % (4.6/5.4 %) 1,2,4-triazole

2.4 % others after 343 d Sandy loam: 1.9 % 1,2,4-triazole after 343 d

3.3 % others after 343 d Sandy loam: 6,6 % (5.3/7.9 %) 1,2,4-triazole after 175 d.(study end, only study end data).

FenbuconazoleRH-0118 (1,2,4-triazole) peaked at 12.4% AR after 363 d [14C-TR] label (25°C)FlunquiconazoleTriazole – 9.0-18.9% after 119-182 d, [14C]-Fluquinconazole – triazolyl label (n = 3 soils at 20 C)

74






Paclobutrazol1,2,4-triazole is no major metabolite in soil, however some end points were derived.

TetraconazoleLaboratory study (dark): no metabolite formationLaboratory study under sunlight:TAA (Triazolyl acetic acid):max: 4.55 and 4.89% after 60 and 112 days (n=1)

TriadimenolTriazole ring not labelled; in absence of other information, 1,2,4-triazole assumed to be formed at 100% for environmental exposure assessment

Route of degradation in soil - Supplemental studies (Annex IIA, point 7.1.1.1.2)

Anaerobic degradation ‡

BitertanolAnaerobic degradation ‡ 1,2,4-triazole

Mineralisation 1.3% after 126 d triazole label (n=1)Non extractable residues max 21% 64 days declining to 16% at study end 126d triazole label (n=1)Major metabolite Triazole acetic acid 50% at study end 126 days triazole label (n=1)

TriadimenolAnaerobic degradation ‡ 1,2,4-triazole

Mineralisation 1.3% after 126 d triazole label (n=1)Non extractable residues max 21% 64 days declining to 16% at study end 126d triazole label (n=1)Major metabolite Triazole acetic acid 50% at study end 126 days triazole label (n=1)

Agreed end point

75






Rate of degradation in soil (Annex IIA, point 7.1.1.2, Annex IIIA, point 9.1.1)

Laboratory studies ‡

BitertanolLaboratory studies (range or median, with n value,with r2 value) ‡

DT50lab (20C, aerobic): ‡1,2,4-triazole20C: 6.3-12.3 d (n=3, r2= 0.75-0.95)triazole acetic acid20C: 6-11 d (n=3, r2= 0.76-0.9)

For FOCUS modelling geometric mean first order 20ºC DT50lab normalised to -10kPa soil moisture:1,2,4-triazole: 7.4 d

DT90lab (20C, aerobic): ‡

1,2,4-triazole20C: 21-41 d (n=3, r2= 0.75-0.95)triazole acetic acid20C: 20-37 d (n=3, r2= 0.76-0.9)

CyproconazoleTriazoleSoil type pH

©

t. oC / % MWHC

DT50/ DT90

(d)

f. f. kdp/kf

DT50 (d)

20C pF2/10kPa

St.

(r2)


Sandy loam

(Laacherhof AXXa)

6.4 20 oC / 34.4 %

6.32 5 0.75 SFO

Loamy sand

(Hanhofen)

5.8 20 oC / 50 %

9.91 13 0.81 SFO

Silt loam

(Laacherhof A III)

6.7 20 oC / 36.4 %

12.27 8 0.95 SFO

Geometric mean/median 9.15/9.91 8.06/8.2

76






DifenoconazoleCGA 71019 1,2,4-triazole

Aerobic conditions

Soil type pH t. oC / % MWHC

DT50/ DT90 (d)

f. f. kdp/kf

DT50 (d)20 C

pF2/10kPa

St.(r2)


sandy loam 6.4 20 / 40 6.3 / 21 - 4.3 0.75 SFOloamy sand 5.8 20 / 40 9.9 / 33 - 7.6 0.81 SFOsilt loam 6.7 20 / 40 12 / 41 - 7.5 0.95 SFOGeometric mean 9.1 / 30.5 6.3Median 9.9 / 33 7.5

EpoxiconazoleLaboratory studies (range or median, with n value, with r2 value) ‡

DT50lab (20C, aerobic): standardised to field capacity pF2 if test soil moisture < field capacity, -10kPa, with Q10 2.2, Walker-equation exponent 0.7. r² > 0.7

Metabolite 2 = 1,2,4-triazole 20 °C, moisture 1st order

not standardised 20 °C, pF2 Loamy sand 10 d 10 dSandy loam 6 d 5 dSilt loam 12 d 9 dgeometric mean DT50lab: 9 d 8 d

Fenbuconazole1,2,4-triazole

Aerobic conditions

Soil type (USDA)

pH(CaCl2

)

t. oC / % MWHC DT50 /DT90 (d) DT50 (d)20C pF2/10kPa

St.(r2)


Sandy loam 6.4 20oC / 40 % MWHC

6.32 / 21.0 5.0 0.75 SFO

Loamy sand 5.8 20oC / 40 % MWHC

9.91 / 33.0 9.9 0.81 SFO

Silt loam 6.7 20oC / 40 % MWHC

12.27 / 40.8 8.2 0.95 SFO

Arithmetic mean 7.7

77






FluquinconazoleLaboratory studies (range or median, with n value, with r2 value)

Aerobic studies:Triazole DT50lab (20 C, aerobic, sfo non-linear regression): 6.32, 9.91, 12.27 d, mean = 9.5 d (n = 3 soils, r2 = 0.75-0.95)Triazole DT50lab (20 C, aerobic, multi-compartment model): 2.34, 9.34, 12.27 d, mean = 7.98 d (n = 3 soils, r2 = 0.95-0.99)

Triazole DT90lab (20 C, aerobic, sfo non-linear regression): 21.0, 32.9, 40.8 d, mean =31.6 d (n = 3 soils, r2 = 0.75-0.95)

For FOCUS gw modelling:Triazole DT50lab (aerobic, 1st order kinetics): mean = 7.0 d (normalized to 10kPa, 20 C with Q10 of 2.2 and B-value of 0.7)

TetraconazoleTriazolyl acetic acid (TAA)

Aerobic conditions

Soil type X1 pH t. oC / % MWHC

DT50/

DT90

(d)

F.F. kdp/kf

DT50 (d)

20C pF2/10kPa

2 Method of calculation

Sand 5.2 (0.01M CaCl2)

20°C / 60% (pF=2.5)

9.6/ 31.8 10.9 12.0 SFO

Loamy sand 5.6 (0.01M CaCl2)

20°C / 60% (pF=2.5)

8.4/ 27.8 8.6 14.1 SFO

Sandy loam 6.3 (0.01M CaCl2)

20°C / 60% (pF=2.5)

18.7/ 62.1

16.7 9.5 SFO

Geometric mean/median DT50:

11.5/ 9.6

11.6 / 10.9

78






TriadimenolLaboratory studies (range or median, with n value,with r2 value) ‡

Aerobic DT50:1,2,4-triazole 20C: 6.3-12.3 d (n=3, r2= 0.75-0.95)triazole acetic acid 20C: 6-11 d (n=3, r2= 0.76-0.9)

Aerobic DT90:1,2,4-triazole 20C: 21-41 d (n=3, r2= 0.75-0.95)triazole acetic acid 20C: 20-37 d (n=3, r2= 0.76-0.9)

Agreed end point

1,2,4-triazole Aerobic conditions

Soil type (USDA)

pH

(CaCl2

)

t. oC / % MWHC

DT50/ DT90 (d)

f. f. kdp/kf

DT50 (d)

20C pF2/10kPa

St.

(r2)


Sandy loam 6.4 20oC / 40 % MWHC

6.32 / 21.0

5.0 0.75 SFO

Loamy sand 5.8 20oC / 40 % MWHC

9.91 / 33.0

9.9 0.81 SFO

Silt loam 6.7 20oC / 40 % MWHC

12.27 / 40.8

8.2 0.95 SFO

Geometric mean 7.4

Agreed End-point for calculating PEC soil for EU assessments 12 days (Not normalised).

79






Laboratory studies ‡ anaerobic

BitertanolDT50lab (20C, anaerobic): ‡1,2,4-triazole58 d (n=1, r2= 0.77.)

CyproconazoleTriazoleSoil type pH t. oC / %

MWHCDT50/ DT90 (d)

f. f. kdp/kf

DT50 (d)20C pF2/10kPa

St.(r2)


Silt loam 7.31 (KCl)

20/40 81/291 ---- ------ 0.972 SFO

Geometric mean/median 81/291DifenoconazoleLaboratory studies 1,2,4- Triazole‡Anaerobic conditions

g/ha1

pH t. oC / % MWHC

DT50 / DT90 (d)

DT50 (d)20 C

pF2/10kPa

St.(r2)


128 7.2 20 / flooded stable - - -

1 Test concentration re-calculated into corresponding g a.s./ha dose for comparison with the representative uses.

TriadimenolAnaerobic:1,2,4-triazole20˚C: DT50 = 58 d (n=1, r2= 0.77.)

Agreed end point

80






Soil adsorption/desorption (Annex IIA, point 7.1.2)

BitertanolKf /Koc ‡

Kd ‡

pH dependence (yes / no) (if yes type ofdependence) ‡

1,2,4-triazoleKfoc:43-120 ml/g, 1/n 0.83-1.016 (n=4)No evidence of pH dependenceArithmetic mean values for FOCUS modelling 89ml/g, 1/n 0.91

Cyproconazole1,2,4-Triazole‡

Soil Type OC % Soil pH Kd Koc Kf Kfoc 1/nAlpaugh Silty clay 1.2 8.8 0.833 120 0.897Hollister Clay loam 3.0 6.9 0.748 43 0.827

Lawrenceville Silty clay 1.2 7.0 0.722 104 0.922Pachappa Sandy loam 1.4 6.9 0.719 89 1.016

Arithmetic mean 0.7555 89 0.91

pH dependence (yes or no) No.DifenoconazoleCGA 71019 (1,2,4-Triazole)‡Soil Type OC % Soil

pHKd

(mL/g)Koc

(mL/g)Kf

(mL/g)Kfoc

(mL/g)1/n

silty clay 0.70 8.8 - - 0.83 120 0.90clay loam 1.74 6.9 - - 0.75 43 0.83silty clay loam 0.70 7.0 - - 0.72 104 0.92sandy loam 0.81 6.9 - - 0.72 89 1.02Arithmetic mean 0.75 89 0.91Median 0.74 82 0.91pH dependence (yes or no) No

81






Epoxiconazole

Kf /Koc ‡


metabolite 1,2,4-triazoleKoc: 43-120, arithmetic mean 89 (n=4)soil pH Koc Kf 1/n Sandy loam 6.9 89 0.720 1.016(62 % sand, 21 % silt, 17 % clay, 1.4 % org. matter, Corg 0.812 %.)Clay loam 6.9 43 0.748 0.827(26 % sand, 46 % silt, 28 % clay, 3.0 % org. matter, Corg 1.74 %.)Silty clay 8.8 120 0.833 0.897(11 % sand, 44 % silt, 45 % clay, 1.2 % org.C matter, Corg 0.696)Silty clay loam 7.0 104 0.722 0.922(9 % sand, 62 % silt, 29 % clay, 1.2 % org. matter, Corg 0.696)

yes (metabolite), increasing sorption with increasing pH

Fenbuconazole

1,2,4-triazoleSoil Type (USDA) OC % Soil pH

(CaCl2)Kf Kfoc 1/n r2

Silty clay 0.70 8.8 0.833 120 0.897 0.996Clay loam 1.74 6.9 0.748 43 0.827 0.997Sand 0.12 4.8 0.234 202 0.885 0.997Silty clay loam 0.70 7.0 0.722 104 0.922 0.998Sandy loam 0.81 6.9 0.720 89 1.016 0.997

Mean1 0.756 89 0.916 -1Results from the sand soil excluded as an outlier

FluquinconazoleKf/Koc

Kd

pH dependence (yes/no) (if yes type of dependence)

Triazole:Kf: 0.234-0.833 mL/g (mean = 0.651 mL/g, 5 soils)Kfoc: 43-202 mL/g (mean = 111.6 mL/g, 5 soils)1/n: 0.827-1.016 (mean = 0.909, 5 soils)Kd: Not determined

No pH dependence for Fluquinconazole or its metabolite, dione.

82






PaclobutrazolMetabolite 1,2-4 triazole ‡

Soil Type OC % Soil pH

(CaCl2)

Kd (mL/g)

Koc

(mL/g)

Kf

(mL/g)

Kfoc

(mL/g)

1/n

Alpaugh 0.70 8.8 0.833 120 0.833 120 0.897Hollister 1.74 6.9 0.748 43 0.748 43 0.827Lakeland 0.12 4.8 0.234 202 0.2341 2021 0.8851

Lawrenceville 0.70 7.0 0.722 104 0.722 104 0.922

Pachappa 0.81 6.9 0.719 89 0.720 59 1.016

Arithmetic mean 0.7561 891 0.91551

pH dependence (yes or no) Yes. Positive correlation with organic carbon, pH and clay content

1 Results from the Lakeland soil were excluded on the basis of being an outlier

83






TetraconazoleTAA(Triazole acetic acid)Soil Type OC % Soil pH Kd Koc Kf Kfoc 1/n

Loamy sand 14.42 3.38

(0.01M CaCl2)

0.150 1.04 adsorb:

0.903;

desorb:

0.786

Clay 0.89 7.55

(0.01M CaCl2)

0.178 20 adsorb:

0.911;

desorb:

0.865

Silt loam 2.13 5.16

(0.01M CaCl2)

0.448 21 adsorb:

0.926;

desorb:

0.820

Geometric mean/median 0.229/ 0.178

7.59/ 20.0

adsorb:

0.913/ 0.911;

desorb:

0.823/ 0.820

pH dependence, Yes or No no

TriadimenolKf /Koc ‡

Kd ‡


1,2,4-triazole Kfoc:43-120 ml/g, 1/n 0.83-1.016 (n=4)No evidence of pH dependence

84






Agreed end pointMetabolite 1,2-4 triazole ‡

Soil Type(USDA) OC % Soil pH

(CaCl2)

Kd (mL/g)

Koc

(mL/g)

Kf

(mL/g)

Kfoc

(mL/g)

1/n

Silty clay 0.70 8.8 0.833 120 0.897Clay loam 1.74 6.9 0.748 43 0.827Sand 0.12 4.8 0.234 202 0.8851

Silty clay loam 0.70 7.0 0.722 104 0.922

Sandy loam 0.81 6.9 0.720 89 1.016

Arithmetic mean (of 4 values excluding the very low OC sand that was considered not representative of agricultural soils)

0.756 89 0.9155

pH dependence (yes or no) No

Mobility in soil (Annex IIA, point 7.1.3, Annex IIIA, point 9.1.2)

Tetraconazole

Column leaching ‡

Tetraconazole metabolites column leaching in slightly humous sand:elution: 200 mm

time period : 2 daysTetraconazole metabolites column leaching in slightly humous sand:Triazole: 59.04% (of applied Triazole)

TAA: 95.53% (of applied TAA)

85






TetraconazoleAged residues leaching ‡

Laboratory study (dark):Aged for (d): 30 dTime period (d): 2 d Elution (mm): 200 mmLaboratory study under sunlight:Aged for (d): 53 d (samples D2 and D3), 48 d (sample D1)Time period (d): 2 d Elution (mm): 200 mmSoil residues post ageingLaboratory study (dark) : % of 14C-Tetraconazole: 96.21%AR% of bound residues: 2.32%ARLaboratory study under sunlight:% of bound residues: 8.50%AR (53 d); 8.38%AR (48d)Characterization of soil residue before leaching was performed just for the 53 d aged sample; Tetraconazole in D2 sample (53 d): 41.80 %ARM14360-alcohol in D2 sample (53 d):8.07 %ARTriazole in D2 sample (53 d):1.97 %ARDFA in D2 sample (53 d):9.97 %ARM14360-acid in D2 sample (53 d): 2.74 %ARTAA in D2 sample (53 d): 4.11 %ARAnalysis of leachateLaboratory study:tetraconazole equivalents in the leachate: 0.15%AR bound residues: 2.13%ARStudy under sunlight:Total residues/radioactivity: 33.15%ARActive substance: 0.00%ARMetabolites: 0.45%AR (M14360-alcohol), 1.88%AR (Triazole), 10.01%AR (DFA), 4.12%AR (M14360-acid), 5.69%AR (TAA)Radioactivity retained in soil segment: 12.93%AR in top 5 cm; 15.29%AR in top 30 cm

86






PEC (soil) (Annex IIIA, point 9.1.3)

CyproconazoleMetabolite I


Triazole

Molecular weight relative to the parent: 0.236 (69.1 g/mol)DT50 (d): 12.3 days.Kinetics: SFO,

Lab worst case

DifenoconazoleCGA 71019 (1,2,4-Triazole)Method of calculation

Initial PECs=Max parent PECs x Max. metabolite in soil x Mol. Wt fraction.where:Max. parent PECs: 0.016 mg/kg (seed treatment); 0.136 mg/kg (apples); 0.096 mg/kg (carrots)Max. CGA 71019 in soil: 23%Molecular weight fraction: 0.170.

EpoxiconazoleMethod of calculation PEC: 1st order kinetic, DT50Lab worst case

standardised to 15 °C of 3 studies: 18 d, 5 cm soil layer, 1.5 kg/L bulk density, with interception (FOCUS) for cereal scenario f = 0.5 (BBCH 25) and 0.7 (BBCH 61). Interval between applications 21 d. ModelMaker, k1_deg = 1st order rate constant BAS 480 F to metabolite 1 1,2,4-triazole 0.0038/d, , k2_deg = 1st order rate constant BAS 480 to metabolite 0.039/d, molar mass correction BAS 480 F to metabolite 1,2,4-triazole 0.211 (69.1 g/mol/329.8g/mol).

FluquinconazoleTriazole

Method of calculation Kinetics: first orderDT50: 12.27 d (worst case first order laboratory value)Soil depth: 5 cm

87






PaclobutrazolMetabolite II: 1,2,4-triazole (CGA 71019)


Peak formation of 1,2,4-triazole from paclobutrazol of 3% AR from laboratory studies (correction factor from parent paclobutrazol = 0.007 taking into account differences in molecular weights).

TetraconazoleTAAMethod of calculation

Molecular weight relative to the parent: MWM = 127.1; MWP = 372.16

DT50 (d): 15 days

Kinetics: 1st order, best fit according to Slide Write Plus software

Field or Lab: representative worst case from laboratory studies.

TriadimenolMethod of calculation

Application rate For M04, a conservative approach has been taken for PECsoil calculation, assuming 100% formation. The longest laboratory DT50 at 20˚C and pF2 with an r2 value ≥0.85 is 8.2 days. Molecular weight correction factor is 0.234. With multiple application scenarios and metabolites, there is uncertainty with respect to peak metabolite formation, and as a worst case, PECsoil for this metabolite is calculated on the basis of the maximum total dose of triadimenol.

The metabolite 1,2-dihydro-triazolone was formed at maximum of 30.8% AR in a study on degradation of M04. Therefore the initial PECsoil has been calculated on the basis of the maximum total dose of triadimenol, molecular weight correction factor of 0.288 and 30.8% AR formation. The initial PECsoil for this metabolite is 0.009 mg/kg.

88






Agreed end pointMetabolite I


Molecular weight relative to the parent: DT50 (d): x daysKinetics: SFOField or Lab: representative worst case from field studies.

Route and rate of degradation in water (Annex IIA, point 7.2.1)

Hydrolytic degradation of the active substance and metabolites > 10 % ‡

pH 5: 1,2,4-triazole: stable at 25 °

pH 7: stable at 25 °

pH 9: 1,2,4-triazole: stable at 25 °

Photolytic degradation of active substance and metabolites above 10 % ‡

Bitertanolmetabolites formed (triazole label, natural water)1,2,4-triazole max 86% AR at 6 test system

days

EpoxiconazoleMetabolite: 1,2,4-triazole, 14C-labelled80 mg/L triazole in distilled water containing humic acid (Fluka). No photochemical loss after 30 days (natural sun light).absorption coefficient < 10 L/mol x cm

Fluquinconazole

[Triazole is not expected to photodegrade in water under environmental conditions, with mean molar extinction coefficients for triazole determined at <0.1 L mol-1 cm-1]

Agreed end point

89






Degradation in water / sediment

Fluquinconazole

Degradation in - DT50 waterwater/sediment - DT90 water

- DT50 whole system - DT90 whole system

Water phase (two different multi-compartment modelling methods used):

Metabolites: Triazole (aerobic) DT50 = 41.9-190 d, (1st order compartmental model TopFit v1, n = 2, r2 = 0.8714-0.9620), DT50 = 11.6-92.5 d, (1st order 5-compartmental model TopFit v2, n = 2, r2 = 0.752-0.936)

Whole system:Metabolites: not determined

Distribution in water / sediment systems (metabolites)

Water phase:Triazole (aerobic) = 0.0-2.3% (day 0), 3.9-5.1% (day 1), 28.8% and 31.6% (day 14 and 63, respectively), 4.5-21.4% (day 100) (n = 2 systems)SN 616368 (aerobic) = max. 2.1% (day 2), 0.6% (day 26), not detected (day 100)

Sediment phase:Triazole (aerobic) = 0.0-0.9% (day 0), 0.0-0.5% (day 1), 21.5% and 37.4% (day 26 and 63, respectively), 26.3-33.7% (day 100) (n = 2 systems)

Triazole: Maximum of 37.4% applied radioactivity in sediment after 100 d.Triazole (aerobic) DT50 in sediment = 105.3-6931.5 d, (1st order 5-compartmental model TopFit v2, n = 2, r2 = 0.937-0.977)For FOCUS surface water modelling a DT50 value in sediment of was set to 730 days.

90






Paclobutrazol1,2-4 triazole Max in water 9.4% A.R. after 84 d.

Water / sediment system

pH water phase

pH sed

t. oC DT50-DT90

whole sys.

St.

(r2)

DT50-DT90

water

r2 DT50- DT90

sed

St.

(r2)


Basing (14C triazole label)

7.6 N/R 22 N/R N/R N/R N/R N/R N/R -

Geometric mean/median

TriadimenolDistribution in water / sediment systems (metabolites) ‡

No metabolites in water or sediment at >1.7% at any time.For environmental exposure assessment, M-04 assumed to form at 100% AR.

Agreed end pointPEC (surface water) and PEC sediment (Annex IIIA, point 9.2.3)

Bitertanol


FOCUS step 2 ‘STEPS 1-2 in FOCUS’, ‘FOCUS surface water tool version 1.1’

1,2,4-triazoleSoil DT50Soil formation fractionWhole aquatic system DT50Aquatic system formation fractionKfoc

7.4 d44 % (x69/337)*999 d*100% (x69/337)89 ml/g

91






CyproconazoleMetabolite TriazoleParameters used in FOCUSsw step 1 and 2

Parameters used in FOCUSsw step 3Molecular weight:69.1Water solubility (mg/L):1,250,000Soil or water metabolite:SoilKoc/Kom (L/kg): 89DT50 soil (d): 8.6 days [Average Lab value, FOCUS normalised]DT50 water/sediment system (d): 300DT50 water (d):300DT50 sediment (d):300Crop interception (%): For Step 3, the model performs this calculation

Parameters used in FOCUSsw step 3 (if performed)

Vapour pressure:2.2 x10-4 PaKom/Koc: 891/n: 0.92 (Freundlich exponent general)Metabolite kinetically generated in simulation-yes:Formation fraction in soil (kdp/kf): (If formation degradation of metabolite is kinetically simulated by PRZM)For FOCUS calculations the maximum occurrence of triazole with respect to parent was set at 90 %

Difenoconazole

CGA 71019 (1,2,4-triazole)Parameters used in FOCUSsw step 1 and 2

Molecular weight (g/mol): 69Water solubility (mg/L): 730Soil or water metabolite: BothKOC (mL/g): 89 (mean value)DT50 soil (d): 6.45 (arithmetic mean of normalised lab values) DT50 water/sediment system (d): 1000 (worst case assumption)DT50 water (d): 1000 (worst case assumption)DT50 sediment (d): 1000 (worst case assumption)Simulated together with parent compound:Crop interception (%): 0 (seed treatment); 70 (apples and carrots)"No drift" option used for seed treatment scenario.Max. occurrence observed (%): Water/Sediment: 9.6 (worst case assumption calc. by RMS)Soil: 23.4

92






EpoxiconazoleMethod of calculation

not required, maximum 1.7 % in water phase of water/sediment study

Fenbuconazole

Parameter 1,2,4-triazoleMol wt. (g/mol) 69.1Water solubility (mg/l) 1000*Max. observed in soil studies (%)

12.4

Max. observed in water/sediment studies

0

Kfoc (ml/g) 89DT50 soil (d) 7.7DT50 water/sediment (d) 999*DT50 water (d) 999*DT50 sediment (d) 999*Application Single application of

7.12g/ha based on total dose of parent of 4 x 70g

a.s./ha used on pome fruit

*worst case assumptions

FlunquinconazoleTriazoleParameters used in FOCUSsw step 1 and 2 Molecular weight (g/mol): 69.07

Water solubility (mg/l): 50.0 mg/lKoc/Kom (ml/g): Koc = 89.0 (mean of 4 values)1/n: 0.91 (mean of 4 values)DT50 soil (d): 7 d (geometric mean)DT50 water/sediment system (d): Not applicableDT50 water (d): 52.1 d (mean value)DT50 sediment (d): 730 d (worst-case value)Maximum occurrence observed (%): 65% (soil), 59.0% (sediment)


Not applicable

Tetraconazole

TAA (triazol acetic acid)Parameters used in FOCUSsw step 1: calculation of initial PECsw

Molecular weight: 372.16Water solubility (mg/l): not providedSoil or water metabolite: soil metaboliteKoc (L/kg): 11.7

93






DT50 soil (d): not usedDT50 water/sediment system (d): not usedDT50 water (d): not usedDT50 sediment (d): not usedCrop interception (%):not usedMaximum occurrence observed (% molar basis with respect to the parent): 14.11 % in soilRatio of field to water body: 10Effective sediments depth of the surface water: 1cmSediment bulk density (kg/L): 0.8Sediment organic carbon content (%): 5Sediment depth of the surface water: 5 cm

Equations from FOCUS Step 1 were used

Triadimenol

Step 2 – M04 (1,2,4-Triazol)Summary of chemical property parameters input to FOCUS Step 2 (version 1.1) for triadimenol and M04 surface water modelling

Input parameter Unit M04 (1,2,4 – triazol)Physico-chemical parametersMolecular mass g.mol-1 69.1Water solubility mg.l-1 700000Soil degradation parameters$Geometric mean Half-life days 9.9***Max. observed formation % 100%**Sediment/water degradation parametersMean Half-life (whole system)

days @999

Max. observed formation % 100%**Sorption parameters£Median KfOC cm3.g-1 89+

@ arbitrary high value as measured data not available, also set for degradation DT50 in water and sediment compartments $ half lives were from field dissipation studies normalised to 20˚C and field capacity moisture content (-10kPa), as recommended by FOCUS guidance. £ see section B.8.2.4. * also set for degradation DT50 in water and sediment compartments; value from 22˚C study, NOT normalised to 20˚C. **extreme worst case assumption *** notifier stated that DT50 soil used was 7 days, geometric mean of temperature and moisture normalised lab data. In practice, value used was 9.9 days, the median uncorrected DT50. + mean value

94






95






Agreed end point 1,2,4-triazoleParameters used in FOCUSsw step 1 and 2

Molecular weight:Water solubility (mg/L):Soil or water metabolite:Koc/Kom (L/kg): (if necessary, soil metabolites)DT50 soil (d): x days (If necessary, Lab or field. In accordance with FOCUS SFO)DT50 water/sediment system (d): (representative worst case from sediment water studies)DT50 water (d):DT50 sediment (d):Crop interception (%):Maximum occurrence observed (% molar basis with respect to the parent)Water:Sediment:


Vapour pressure:Kom/Koc:1/n: (Freundlich exponent general or for soil ,susp. solids or sediment respectively)Metabolite kinetically generated in simulation (yes/no):Formation fraction in soil (kdp/kf): (If formation degradation of metabolite is kinetically simulated by PRZM)

PEC (groundwater) (Annex IIIA, point 9.2.1)

BitertanolMethod of calculation and type of study (e.g. modelling, monitoring, lysimeter )

FOCUSPELMO 3.2.2 modelling for scenarios pertinent to top fruit and cereals.

1,2,4-triazoleGeometric mean Soil DT50 (-10kPa 20ºCSoil formation fractionKfoc1/n

7.4 d100 % 89 ml/g0.91

96






CyproconazoleMethod of calculation and type of study (e.g. modelling, field leaching, lysimeter)

PECgw were calculated using the FOCUS PELMO modelMetabolites Triazole Data as for parent (cyproconazole) with the following exceptions:Median parent DT50 field 8.6 d (normalisation to 10 kPa or pF2, 20°C with Q10 of 2.2).Koc: triazole, mean 89, 1/n= 0.92.Assuming a 90 % transformation rate from parent to metabolite.

DifenoconazoleMethod of calculation and type of study (e.g. modelling, field leaching, lysimeter )

Model used: FOCUS PEARL 2.2.2Scenarios: Difenoconazole and the metabolites CGA71019 and CGA 205375 were simulated in separate model runs.

CGA 71019 (1,2,4-triazole):DT50 soil (d): 6.45 (arithmetic mean of normalised lab values)Koc (mL/g): 89 (mean value)1/n: 0.9 (mean value)

EpoxiconazoleMethod of calculation and type of study (e.g. modelling, monitoring, lysimeter )

FOCUS-PELMO 2.2.2 and FOCUS-Macro 3.3.1 Metabolite 1,2,4-triazole: DT50 lab 8 (20°C, pF2 standardised). Koc 43, 1/n 0.827, water sol. 700 mg/L,pH independent, TSCF (crop uptake default 0.5)

FenbuconazoleMethod of calculation and type of study (e.g. modelling, field leaching, lysimeter )

Mean 1,2,4-triazole Kfoc: 89 ml/gMean 1,2,4-triazole 1/n: 0.9 (default)

FluquinconazoleMethod of calculation and type of study (e.g. modelling, monitoring, lysimeter)

Modelling using FOCUS groundwater scenarios

Model used: FOCUS PELMO 3.3.2 including the FOCUS shell and simulation model.

Triazole: calculations were based on a mean DT50 value of 7.0 d (determined from a laboratory study, corrected to pF2 moisture and

97






20 C where appropriate). Averaged Freundlich sorption data used were Kfoc 89.0 ml/g and 1/n = 0.91. A temperature correction exponent (Q10) of 2.2 and a moisture correction exponent (B) of 0.7 were used. A transformation rate of 65% (Fluquinconazole to triazole) was used, based on a calculated formation fraction.

TetraconazoleTAAMethod of calculation and type of study (e.g. modelling, field leaching, lysimeter )

For FOCUS gw modelling, values used –Model(s) used: FOCUS-PELMO 3.3.2TAADT50 lab :9.7 (mean value, not normalized)Koc: 11.7 (worst case mean value); 1/nads = 0.9 (default value)

TriadimenolM04

ParametersMolecular weight 69.1Solubility in water (mg/l at 20˚C)Vapour pressure (Pa at 20˚C)First order DT50 (days) 7Reference temperature (˚C) 20Reference soil moisture (pF) 2Activation energy (kJ/mole) 54Moisture exponent 0.7Kom-value (ml/g) 51.7Exponent of the Freundlich isotherm 0.92Formation fraction 1

Agreed end pointMethod of calculation and type of study (e.g. modelling, field leaching, lysimeter )

Geometric mean or median DT50lab/field x d (normalisation to 10kPa or pF2, 20 C with Q10 of 2.2).KOC: parent, arithmetic mean or median x, 1/n= y.

98






99

Date post:	22-Mar-2020
Category:	Documents
Upload:	others
View:	38 times
Download:	2 times

FATE EVALUATION: 1,2,4-Triazole - Revision to DT50s ... · Web viewTriazole Derived Metabolite:...

Documents