title: Spatial patterns and temporal trends in mercury concentrations, precipitation depths, and mercury wet deposition in the North American Great Lakes region, 2002-2008.
abstract: Annual and weekly mercury (Hg) concentrations, precipitation depths, and Hg wet deposition in the Great Lakes region were analyzed by using data from 5 monitoring networks in the USA and Canada for a 2002-2008 study period. High-resolution maps of calculated annual data, 7-year mean data, and net interannual change for the study period were prepared to assess spatial patterns. Areas with 7-year mean annual Hg concentrations higher than the 12 ng per liter water-quality criterion were mapped in 4 states. Temporal trends in measured weekly data were determined statistically. Monitoring sites with significant 7-year trends in weekly Hg wet deposition were spatially separated and were not sites with trends in weekly Hg concentration. During 2002-2008, Hg wet deposition was found to be unchanged in the Great Lakes region and its subregions. Any small decreases in Hg concentration apparently were offset by increases in precipitation.
authors: U.S.Geological Survey, 5957 Lakeside Boulevard, Indianapolis, IN 46278, USA. mrrisch@usgs.gov
authors: Martin R
authors: MR
authors: Risch
authors: David A
authors: DA
authors: Gay
authors: Kathleen K
authors: KK
authors: Fowler
authors: Gerard J
authors: GJ
authors: Keeler
authors: Sean M
authors: SM
authors: Backus
authors: Pierrette
authors: P
authors: Blanchard
authors: James A
authors: JA
authors: Barres
authors: J Timothy
authors: JT
authors: Dvonch
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D004784:Environmental Monitoring; D019015:Geologic Sediments / Q000737:chemistry; D006114:Great Lakes Region; D060106:Lakes / Q000737:chemistry; D008628:Mercury / Q000032:analysis*; D009864:Ontario; D011792:Quebec; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*; D014887:Weather
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury