TOXMAP: a GIS-based gateway to environmental health resources.

The National Library of Medicine (NLM) has an extensive collection of environmental health information, including bibliographic and technical data on hazardous chemical substances, in its TOXNET <http://toxnet.nlm.nih.gov> databases. TOXNET also provides access to the United States Environment Protection Agency (EPA)'s Toxics Release Inventory (TRI) data, which covers release of specific chemicals via air, water, and land, and by underground injection, as reported by industrial facilities around the United States. NLM has developed a Web-based geographic information system (GIS), TOXMAP <http://toxmap.nlm. nih.gov/>, which allows users to create dynamic maps that show where TRI chemicals are released and that provides direct links to information about the chemicals in TOXNET. By extracting the associated regional geographic text terms from the displayed map (e.g., rivers, towns, county, state), TOXMAP also provides customized chemical and/or region-specific searches of NLM's bibliographic biomedical resources. This paper focuses on TOXMAP's features, data accuracy issues, challenges, user feedback techniques, and future directions.