January 11, 2011 EMPM Agenda and Abstracts

PRESENTER Time TOPIC Duration
Shelby/Garber 9:00 am Welcome and Introduction 10 minutes

Russell Jones

, ECPA Kinetics Group 9:10 am Estimating Confidence Intervals for Metabolite Degradation Rates 35 minutes

Cody Howard, USDA/ARS 9:45 am Determining the Fate and Transport of Pesticide

Emissions in the Chesapeake Bay Region 35 minutes

10:20 am Break 10 minutes

Ed Odenkirchen,

USEPA/EFED 10:30 am Developments in Terrestrial Exposure Modeling 45 minutes

Tom Purucker, NERL/EPA 11:15 am Dermal Contact, Movement, and Amphibian Pesticide Exposure 35 minutes

William Stiteler, PhD,

ARCADIS US Inc. 11:50 am Habitat Classification for Ecological Risk Assessment Using Aerial Photography and GIS Data

in a Two

- stage Expert System 35 minutes

Shelby/Garber 12:25 pm Wrap

- up, Next Meeting 5 minutes
Shelby/Garber 12:30 pm AdjournmentEstimating Confidence Intervals for Metabolite Degradation Rates R. L. Jones, C. Beigel, B. Erzgraeber, Z. Gao , J. W. Green, B. Harvey, S. Hayes, N. Mackay, K. Paul, W. Schmitt, and D. Yon, ECPA Kinetics Group

Regulatory agencies around the world are switch to formation decline kinetics for estimating degradation rates of metabolites. Estimating confidence inter vals of metabolite degradation rates obtained using such kinetic analysis has become an important element of the registration process, especially in Europe. When confidence intervals are estimated using ordinary least squares regression techniques, the re sulting confidence intervals are overly broad. Other standard techniques such as IRLS (Iteratively Reweighted Least Squares) and MCMC (Markov Chain Monte Carlo) provide more appropriate estimates of confidence intervals since these two techniques do not a ssume that the error variance is the same for parent and metabolites.

Determining the Fate and Transport of Pesticide Emissions in the Chesapeake Bay Region Cody Howard, USDA/ARS

Environmental scientists have primarily focused on the fate, transport, and toxicity of pesticide active ingredients, but relatively little research has been conducted to examine the environmental fate of pesticide inactive ingredients, sometimes termed formulants or inerts. Many formulants are volatile organic compounds that ma y contribute to ground

- level ozone pollution. In California, a system of formulation testing using thermogravimetric analysis (TGA) is used to estimate VOC emission potential for pesticide products. A critical analysis of several available

methods for es timating VOC emissions and ozone formation potential (OFP) of pesticide products was evaluated. The methods examined were TGA alone; TGA with calculated OFP from confidential formulation information; TGA

- FTIR of evolved gases and calculation of OFP; and g as

- chromatography

- mass spectrometry and calculation of OFP.

Further research studies are focused on measuring the concentration of selected pesticides, agriculturally

- related emerging contaminants, and VOCs in surface agricultural soils collected

from r epresentative sites across the agriculture

- urban interface of the Chesapeake Bay. The collected data will be used to develop emissions inventories for selected gaseous compounds using the Pesticide Emissions Model. Input files for initial model calibrati on will be populated with soil concentration, soil property, soil moisture, and meteorological data from a multi

- year study of pesticide fate carried out at the USDA.

Developments in Terrestrial Exposure Modeling Ed Odenkirchen, USEPA/EFED

The Environmen tal Fate and Effects Division, Office of Pesticide P rograms, United States Environmental Protection Agency (EFED) has been working to enhance it's methods for problem

formulation and e xposure assessment phases of the ecological risk assessment process for terrestrial wildlife to be more mindful of the potential for toxicologically significant exposures from a variety of pathways beyond the traditionally assessed dietary route. These enhanced

m ethods are intended to provide transparent, reasonable, concise and consistent evaluations of the potential pesticide risks posed by the drinking water, inhalation, and dermal exposure routes.This presentation will discuss past assumptions, present problem formulation screening tools for prioritizing data collection and risk assessment efforts, and development efforts for first tier screening risk assessment tools.

Dermal Contact, Movement, and Amphibian Pesticide Exposure

Tom Purucker

, National Exposure Research Lab, ORD Athens, GA Tanja Crk, Ed Odenkirchen, USEPA, EFED

The more terrestrial an amphibian’s life cycle is, the more likely it is to use the skin to regulate its water content in order to maintain hydration. Therefore, amphibian dermal contact from enhanced skin permeability can be a key exposure pathway compared to non

- amphibian receptors. Hydrophilic and lipophilic molecules have separate pathways for dermal exposure, with neutral, lipophilic molecules traditionally getting the most attention in humans and other mammals. However, preferential water upt ake by the seat patch in amphibians increases the effective surface area for osmosis and may enhance the potential for low Kow dermal contaminant exposures. Therefore, although amphibian epidermis has some capability to limit exposures to contaminants, po sitive linear relationships between Kow and contaminant flux across amphibian skin are significantly higher in amphibians versus mammals. In addition, sustained direct contact with soil from daily movement patterns, overnight burrowing, and

aestivation/hi bernation periods further complicates chronic exposure estimation for amphibians. We review recent data and methods concerning amphibian exposures to identify a set of algorithms and parameters for screening and higher

- tier model selection purposes that accounts for the increased dermal contact exposure potential and movement behavior.

Habitat Classification for Ecological Risk Assessment Using Aerial Photography and GIS

Data in a Two

- stage Expert System William Stiteler, PhD, ARCADIS US Inc.

There are many challenges in performing a land cover classification that can be used for habitat suitability analysis of multiple species in ecological risk assessments. The classification scheme must be detailed enough to allow for use to several different habitat requirements, as well as flexible enough to be applicable to different species. Because habitat suitability often has minimum area requirements, but does not require regular shapes of contiguous cover, high spatial resolution is useful, but imagery of hi gh spatial resolution often lacks the spectral resolution useful for habitat classification. We present the results of a land cover classification designed to allow for the modeling of habitat suitability for a variety of receptors, such as shrews, robins , and deer. A hybrid remote sensing / GIS approach was developed that uses both aerial photography and ancillary GIS data. A two

- stage expert system is used to bring together different data sources. This expert system was designed to work with a particu lar set of data sources, but it can be easily adapted to other sources. The result is a land cover classification with fourteen classes, a minimum mapping unit of 1/20 acre, and distinct polygons that can be as

narrow as four feet wide. Ground reference data from field visits showed an overall accuracy of approximately 80% for qualitatively different classes and 60% for the full classification scheme containing quantitative class divisions, such as those between closed, intermediate, and open

canopy cover classes.