; or (B) mass per unit of area of land or water per unit of time. (7) Program The term program means the national mercury monitoring program established under section 4(a). (8) Surface sediment The term surface sediment means sediment in the uppermost 2 centimeters of a lakebed, riverbed, estuary, or coastal area. 4. Monitoring program (a) Establishment (1) In general The Administrator, in consultation with the Director of the United States Fish and Wildlife Service, the Director of the United States Geological Survey, the Director of the National Park Service, the Administrator of the National Oceanic and Atmospheric Administration, and the heads of other appropriate Federal agencies, shall establish a national mercury monitoring program. (2) Purpose The purpose of the program is to track— (A) long-term trends in atmospheric mercury concentrations and deposition; and (B) mercury levels in watersheds, surface water, and fish and wildlife in terrestrial, freshwater, coastal, and marine ecosystems in response to changing mercury emissions over time. (3) Monitoring sites (A) In general In carrying out paragraph (1), not later than 1 year after the date of enactment of this Act and in coordination with the Advisory Committee, the Administrator shall select multiple monitoring sites representing multiple ecoregions and associated coastal waters of the United States. (B) Locations Locations of monitoring sites shall include— (i) units of the National Park System; (ii) units of the National Wildlife Refuge System; (iii) units of the National Estuarine Research Reserve System