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Federal
USGS Water-Quality Data for the Nation - National Water Information System (NWIS)
Department of the Interior —
The USGS compiles online access to water-resources data collected at approximately 1.5 million sites in all 50 States, the District of Columbia, Puerto Rico, the... -
Federal
USGS National Structures Dataset - USGS National Map Downloadable Data Collection NGDA
Department of the Interior —
USGS Structures from The National Map (TNM) consists of data to include the name, function, location, and other core information and characteristics of selected... -
Federal
Map of Arsenic concentrations in groundwater of the United States
Department of the Interior —
The map graphic image at https://www.sciencebase.gov/catalog/file/get/63140561d34e36012efa2b7f?name=arsenic_map.png illustrates arsenic values, in micrograms per...