Temporal and spatial trends in freshwater fish tissue mercury concentrations associated with mercury emissions reductions.
Mercury (Hg) concentrations were monitored from 1999 to 2011 in largemouth bass (LMB) and yellow perch (YP) in 23 lakes in Massachusetts USA during a period of significant local and regional Hg emissions reductions. Average LMB tissue Hg concentration decreases of 44% were seen in 13 of 16 lakes in a regional Hg "hotspot" area. YP in all lakes sampled in this area decreased 43% after the major emissions reductions. Comparative decreases throughout the remainder of the state were 13% and 19% for LMB and YP respectively. Annual tissue mercury concentration rate decreases were 0.029 (LMB) and 0.016 mg Hg/kg/yr (YP) in the hotspot. In lakes around the rest of the state, LMB showed no trend and YP Hg decreased 0.0068 mg Hg/kg/yr. Mercury emissions from major point sources in the hotspot area decreased 98%, and 93% in the rest of the state from the early 1990s to 2008. The significant declines in fish Hg concentrations in many lakes occurred over the second half of a two decade decrease in Hg emissions primarily from municipal solid waste combustors and, secondarily, from other combustion point sources. In addition to the substantial Hg emissions reductions achieved in Massachusetts, further regional, national and global emissions reductions are needed for fish Hg levels to decrease below fish consumption advisory levels.
Office of Research and Standards, Massachusetts Department of Environmental Protection, 1 Winter Street, Boston, Massachusetts 02108, United States.
Michael S
MS
Hutcheson
C Mark
CM
Smith
Jane
J
Rose
Carol
C
Batdorf
Oscar
O
Pancorbo
Carol Rowan
CR
West
Joseph
J
Strube
Corey
C
Francis
D000818:Animals; D001492:Bass / Q000378:metabolism*; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D005843:Geography; D060106:Lakes / Q000737:chemistry; D008404:Massachusetts; D008628:Mercury / Q000032:analysis*; D010471:Perches / Q000378:metabolism*; D062611:Solid Waste; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*
D062611:Solid Waste; D014874:Water Pollutants, Chemical; D008628:Mercury