The National Environmental Public Health Tracking Network  
http://ephtracking.cdc.gov/showHome.action
 http://ephtracking.cdc.gov/showHome.action
"Environmental causes of chronic diseases are hard to identify. Measuring amounts of hazardous substances in our environment in a standard way, tracing the spread of these over time and area, seeing how they show up in human tissues, and understanding how they may cause illness is critical. The National Environmental Public Health Tracking Network is the start of that system.
The National Environmental Public Health Tracking Network is a system  of integrated health, exposure, and hazard information and data from a variety  of national, state, and city sources. On the Tracking Network, you can explore  information and view maps, tables, and charts about health and environment  across the country. Learn more about tracking."