N-(2-nitrophenyl)phosphoric triamide

Distribution modelling

Administrative data

Endpoint:

distribution modelling

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

supporting study

Study period:

2006-09-28

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Model:

other: PELMO (Pesticide Leaching Model )

Calculation programme:

PELMO 3.0, developed by the Fraunhofer-Institut für Umweiichemie und Ökotoxikologie

Media:

water - soil

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

477-690-9

EC Name:

-

Cas Number:

874819-71-3

Molecular formula:

Hill formula: C6H9N4O3P CAS formula: C6H9N4O3P

IUPAC Name:

N-(diaminophosphoryl)-2-nitroaniline

Test material form:

solid: crystalline

Study design

Test substance input data:

Mobility and degradability of a pesticide predominantly influence its leaching behaviour. The koc-values available for N-(2-nitrophenyl)phosphoricacid triamids were in the range of 20 L/kg to 180 L/kg (soil/water ratio = 5/1, n=3 and soii/water ratio 1/1, n=3) indicating only weak to moderately sorption to soil. For the simulations a koc value of 100 (ar. mean of 6) was considered.

The experimental DT50 of N-(2-nitrophenyl)phosphoricacid triamide were in the range of 3.91 days to 8.61 days. For the simulations a DT50 value of 8.61 days (related to 40 % field capacity as recommended by German authorities as a standard value) was considered representing the worst case situation.

First order kinetics was assumed for the degradation in all simulations. Temperature corrections (QlO-factor of 2.2) and soil moisture corrections (moisture exponent of 0.7) were performed. The correction was in agreement with the European FOCUS recommendations.

Four different application patterns were analysed on the basis of the sponsor's information that N-(2-nitrophenyl)phosphoricacid triamide is used in winter wheat winter barley, winter rape, and maize. The annual dose was 150 g/ha for all simulations. However, the application dates were selected individually dependent on the crop type based on information given by the sponsor. Crop interception was considered dependent on the crop and the crop development stage according to the European (FOCUS) and German recommendations. The standard plant uptake factor of plants 0.5 was used for all simulations. All simulations were performed with a single soil scenario (Borstef soil). The Borstel soil is the official soil scenario in German pesticide registration. A single climate variation was considered alternating Hamburg wet (872 mm annual rainfall) and Hamburg normal (778 mm annual rainfall) conditions.

Results and discussion

Percent distribution in media

Water (%):

0

Applicant's summary and conclusion

Conclusions:

Annual percolate concentrations at 110 cm depth were simulated to be 0.000 µg/L independent on the crop simulated.

If the input data on degradation and sorption which were used in the computer simulations are valid under agricultural conditions considerable annual concentrations of N-(2-nitrophenyl)phosphoricacid triamide above 0.1 µg/L in the percolate at 1.1 m soil depth are not expected.

Executive summary:

To assess the leaching potential of pesticides PELMO, the Pesticide Leaching MOdel was usecd by German authorities who are involved in the licensing procedure of plant protection products (ÜBA Umweltbundesamt Berlin, and BBA Biologische Bundesanstalt Braunschweig). The versions PELMO 1.0 and 2,01 were developed by the Fraunhofer-Institut für Umweiichemie und Ökotoxikologie and is based on R.F. Carsel's PRZM-Model. The current version PELMO 3.0 is additionally able to simulate the fate of metabolites (development of the institute „SLFA" in Neustadt (Germany). PELMO is a compartmental model for the simulation of chemical movement in the unsaturated soil system within and below the plant root zone. Transport on the passage of time including advection and dispersion are represented in the program. Sorption is estimated based on the Freundlich equation, degradation of pesticides in soil is corrected based on temperature and soil moisture. In this study the fate of N-(2-nitrophenyl)phosphoricacid triamide was simulated using the German standard scenario for applications in winter wheat, winter barley, winter rape, and maize according to the GAP.

Annual percolate concentrations at 110 cm depth were simulated to be 0.000 µg/L independent on the crop simulated. If the input data on degradation and sorption which were used in the computer simulations are valid under agricultural conditions considerable annual concentrations of N-(2-nitrophenyl)phosphoricacid triamide above 0.1 µg/L in the percolate at 1.1 m soil depth are not expected.