WORLD EXPOSURE ASSESSMENT TOOLS AND SCENARIOS Amy M. Ritter, J. Mark Cheplick

Waterborne Environmental, Inc., USA

ABSTRACTModelling platforms have been developed to evaluate the potential impact of crop protection chemicals on the environment throughout the world. The tools currently have been configured with scenarios containing crop, soil, and weather conditions for major agricultural areas in Brazil, Canada, Colombia, the European Union, Norway, the People’s Republic of China, and the United States. Additionally, agricultural scenarios have been developed for countries such as Peru, Ecuador, Taiwan, Philippines, and South Korea. All these scenarios are simulated using fate and transport models that have been accepted for regulatory assessment in the U.S. and the European Union, including the Pesticide Root Zone Model (PRZM), Exposure Analysis Modeling System (EXAMS), Rice Water Quality Model (RICEWQ), and Toxic Subtances in Surface Waters (TOXSWA). Development of country specific scenarios and tools are described in this poster. A key strength of the tools are that scenarios can be added for addtional geographical areas with relative ease and the appropriate regulatory endpoints.

DISCUSSION OF CAPABILITIES

As discussed in the guidance document for FOCUS surface water scenarios (FOCUS, 2001), “the existence of standard scenarios will make a uniform procedure for assessing the predicted environmental concentrations (PECs) of plant protection products in surface water possible.” A tool that contains a variety of models for simulating PECs in surface water and groundwater with country-specific standard scenarios could help expand the use of regulatory modelling to countries which currently do not employ these methods. Development of this tool also allows for easier programming maintenance as country specific modelling shells would no longer be required. WEAT provides scenarios that cover a wide variety of hydrologic, soil, weather, and cropping conditions and provide output specific to the regulatory endpoints of selected countries.

The advantage of the WEAT shell is the ability to simulate groundwater and surface water predicted environmental concentrations (PECs) with one tool (Figure 2). In addition, WEAT can simulate exposure from products used on rice with the RICEWQ model. For evaluation of PECs in groundwater, the winPRZM model is run for PECs at 1-m depth and the ADAM model is run for dilution in groundwater at greater depths (Figure 3). Other advantages of WEAT include the ability to recall/share previously created user simulations (master project files) and the ability to use/import scenarios created by other user/regulators around the world.

CURRENT STATUS

Several features of WEAT are completed such as compatibility with FOCUS GW, RICEWQ windows, PRAESS, Norway, Brazil, and Colombian Scenario tool. Some intended features are not yet completed: FOCUS-SW capability (current TOXSWA limitations 1-yr hard coded), full implementation of PWC (PWC is still evolving).

INTENDED USERSSome of the intended users of the current WEAT shell will be modelers who wish to:1) Augment the existing scenarios found in the FOCUS GW shell - i.e. add to the 125 current scenarios2) PWC users who wish to utilize features found in WinPRZM - for example to compare scenario results with using Kinetic Sorption vs. No Kinetic Sorption, etc...3) Modelers in countries who do not have well developed modeling shells specific to their country

REFERENCES 1. FOCUS (2001) - FOCUS Surface Water Scenarios in the EU Evaluation Process under 91/414/EEC. Report of the FOCUS Working Group on Surface Water Scenarios, EC Document Reference

SANCO/4802/2001-rev. 2 final (May, 2003) . 2. FOCUS (2000) - FOCUS groundwater scenarios in the EU review of active substances. Report of the FOCUS Groundwater Scenarios Workgroup, EC Document Reference SANCO/321/2000 rev.

2, 202pp.3. FOCUS (2007) Landscape And Mitigation Factors In Aquatic Ecological Risk Assessment. Volume 1. Extended Summary and Recommendations, The Final Report of the FOCUS Working Group

on Landscape and Mitigation Factors in Ecological Risk Assessment, EC Document Reference Sanco/10422/2005, version 2.0, September 2007

Figure 1: World Exposure Assessment Tool (WEAT) - Main Screen

World Exposure Assessment Tool, v1.0 ( beta coming fall 2011)

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Figure 2: Scenario selection screenshowing China scenarios

Figure 3: Output results shown in graphical post processing tool

For more information, contact: Amy Ritter or Mark Cheplick, 897-B Harrison Street, Leesburg, VA 20175email: or , phone: 00+1+703 777-0005rittera@waterborne-env.com cheplickm@waterborne-env.com

A SUMMARY EXISTING REGULATORY SHELLS, INPUT PARAMETER DATABASES, OUTPUT ENDPOINTS Selecting appropriate models and developing inputs has proven to be a difficult and expensive task. The USEPA and EFSA first created scenarios and tools starting 1996 and 2001, respectively. These same tasks continue today with refinements, corrections, and additions to the scenarios. ICAMA (China) started in 2009 and is just completing a first release now in 2015. Different philosophies are utilized in the development of scenarios and model selection between regulatory bodies. However, comparison of the various approaches has yielded valuable insights in model performance and scenario development. The creation of a tool like WEAT can further this effort by making the comparison easier and more consistent. Additionally, newer regulatory agencies can more easily understand the differences in the approaches with a tool that allows direct comparison of scenarios within the same tool.Regulatory Body

Media Surface Water Ground Water RICE Surface Water Ground Water RICE Surface Water Ground Water RICE Surface Water RICE GW Surface Water Ground Water RICE

Tool Name Pesticide Water PRZM- GW PFAM SWASH Various GW models EU-RICE None China-PEARL TOP-RICE PRAESS PRAESS WEAT WEAT WEAT

Calculator (PWC)

Models PRZM5 - VVWM PRZM5 PFAM PRZM/TOXSWA or PEARL, PELMO, MEDRICE + - PEARL PEARL PRZM/EXAMS RICEWQ/VADOFT/ PRZM/EXAMS or WinPRZM PFAM or

MACRO/TOXSWA MACRO, WinPRZM RICEWQ ADAM PRZM/VVWM RICEWQ

# of Scenarios 127 6 11 (unofficial) 125 2 MEDRICE - 28 2 4 18 TBD TBD TBD

Output Endpoints 90th (1-10 year) 90th Dissolved water 90th (1-10 year) 1-year 80th (1-5 year) Paddy soil/water - 90th Dissolved water SW - peak in water 90th (1-10 year) 90th (1-10 year) 90th (1-10 year) 90th (1-10 year) 90th (1-10 year)

water,benthic,sed conc. 6 or 10m water,benthic,sed 96 hr PEC Dissolved water Canal Soil/water at 1m GW - 90th dissolved water,benthic,sed water,benthic,sed,gw water,benthic,sed 1m, 10m, 11m aquifer water,benthic,sed,gw

peak, 4,21,60,90 Peak, Breakthrough, peak, 4,21,60,90 conc. 1m water at 1m peak, 4,21,60,90 peak, 4,21,60,90 peak, 4,21,60,90 peak, 4,21,60,90

365 day (Pond/Res) Simulation ave. 365 day (Paddy) 365 day (Pond/Res) 365 day (Pond/Riv.) 365 day (Pond/Res) 365 day (Pond/Riv.)

WEAT Compatible Yes Yes Yes Yes when new TOXSWA Yes - WINPRZM Yes - Unsure Unsure Yes Yes Yes Yes Yes

MEP - CHINA (NIES) Others* (Norway,Brazil,Colombia, Korea, Japan, Vietnam) EPA - USA EFSA - EU ICAMA - China