![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Probabilistic Model Informing Pesticide Risk Assessment
On a daily basis people encounter a variety of chemicals that enter the body through food, water, and air, as well as by skin contact. Scientists with the U.S. Environmental Protection Agency's Office of Research and Development are developing tools to estimate how we are exposed to different chemicals and to better understand the human health risks from exposure to mixtures of chemicals. The Stochastic Human Exposure and Dose Simulation (SHEDS)-Multimedia Model is the primary tool used by ORD for simulating chemical exposures.
The dietary (food and drinking water) module of the SHEDS-Multimedia model is being applied to support EPA's cumulative risk assessment for n-methyl carbamate pesticides. This group of closely related pesticides is commonly used in homes, gardens and agriculture and can affect the functioning of the nervous system, leading to overstimulation of nerves and muscles and causing such symptoms as weakness or paralysis of the muscles.
The overall goal of the n-methyl carbamate cumulative risk project is to develop models to meet EPA's assessment needs under the Food Quality Protection Act. Specifically, researchers are developing models that will allow them to provide accurate estimates of human exposure and to assist risk management decisions
“The new model for assessing children's exposure via hand-to-mouth is particularly important to helping determine potential risk,” said Jack E. Housenger, Associate Director, Health Effects Division, Office of Pesticide Programs. “In addition, n-methyl carbamates challenge us to assess hourly dietary exposure and the enhanced capability of SHEDS is providing risk managers with timely sensitivity analyses.”
Because of the unique SHEDS time series approach, the SHEDS-Multimedia dietary module is able to help answer regulatory-related questions regarding the contribution of different foods and number of eating occasions. In the end, EPA's cumulative risk assessment of n-methyl carbamates will help to protect human health by providing better guidance regarding the possible dangers from exposure to a variety of common pesticides.