• Hg concentration in precipitation ranged from 7.8 to 10.5 ppb at Underhill, Vermont.
• Annual average deposition at Underhill was 9.7 µg/m2/yr in 2002.
• A new mercur y model estimated total deposition in the Northeast f rom 3.0 to 41.0 µg/m2/yr.
• Higher concentrations of Hg occured in spring and summer.
• The highest levels of Hg in precipitation were associated with regional t ransport from the west and southwest, regardless of season.

Sediments (Papers 7 and 8)

• The total Hg in sediment ranged from 0.01 to 3.7 ppm.
• MeHg in sediments ranged from 0.15 to 21.0 ppb.
• Sediment cores Hg accumulation has declined since 1970–1980.
• Hg accumulation rates in sediment were 3-5x above background.
• At least 44% of waters across the region had sediments in excess of U.S. guidelines.
• Highest Hg values values were observed in lakes.
• No spatial pattern was detected, but high values occur more commonly in Massachusetts and southeastern New Hampshire.

Water (Papers 9, 10 and 11)

• Total Hg values in surface waters across the region ranged from below detection of 0.5 to 19.5 ppt.
• MeHg levels ranged from 0.01 to 3.12 ppt. The highest average value occured in Nova Scotia.
• MeHg was generally 15% of total mercury, except in urbanized Massachusetts which was lower.
• Waters with t he highest total Hg and MeHg levels were distant from point sources and had abundant wetlands.
• Waters with ver y high total Hg were detected near urbanized regions of Boston, Massachusetts and Portland, Maine; areas with high MeHg are
  reported in central Massachusetts and southern New Hampshire.

Aquatic Birds (Papers 15, 17 and 18)

• Hg in aquatic birds increased from marine areas to estuaries and rivers, and was highest in lakes.
• Hg levels ranged from low to high as follows: wood duck < tree swallow < belted kingfisher < common merganser < common loon.
• Adult blood Hg was 5-10x > nestling blood.
• Male loon Hg levels were > female levels due to males averaging 20% larger.
• Hg levels increased wit h age if Hg consumption exceeded elimination.
• Ratio of liver, muscle, blood Hg levels in loons followed t he 7:3:1 rule.
• Some waterfowl species exceeded the EPA MeHg criterion in their breast muscle; although most edible species were below 0.30 ppm.
• More than 1,800 blood and egg Hg levels in loons indicated at least 9 distinct biological hotspots.
• Insect-eating songbird Hg levels generally increased with body mass.
• Some insect-eating songbirds (such as nort hern waterthrush) had blood Hg levels that exceed much larger fish-eating species (such as eagles)
• The percent of wetlands within 500 feet of common loon territory were positively correlated with loon blood mercury levels.
• 92% of adult loons in Kejimkujik National Park in Nova Scotia had blood mercur y levels >4.0 ppm, levels associated with lowered reproduction.

Fish (Paper 13)

• Hg levels across all fish species ranged
  from 0.09 to 1.02 ppm.
• 42% of waters had average Hg levels in yellow perch above current U.S. EPA MeHg tissue criterion.
• 15% of waters had average Hg levels in brook trout that exceeded t he U.S. EPA MeHg tissue criterion.
• Highest Hg concentration occured in white perch in reser voirs (1.02 ppm).
• Fish lengt h was an important predictor of Hg content.
• In 8 of t he 13 fish species analyzed, Hg was highest in reservoirs.
• Forested areas wit h acidic or tannic waters showed higher fish Hg concentrations.

Crayfish (Paper 12)

• Hg concentrations ranged from 0.04 to 0.50 ppm.
• Half of t he crayfish examined had mercur y levels above t he expected background level of 0.10 ppm.
• Larger crayfish and crayfish living in streams had the highest Hg.
• Nearly all of the Hg existed in t he toxic MeHg form (88%).

Salamanders (Paper 14)

• Mercur y concentrations in salamanders ranged from 0.02 to 0.08 ppm.
• MeHg comprised up to 97% of total Hg in larval salamander composites.
• The highest concentrations of Hg were in salamanders in t he unburned watersheds of Acadia National Park (ANP).
• Acidic streams in the Bear Brook Watershed had significantly higher total Hg in salamander larvae.
• Both larval and adult salamanders had significantly higher total Hg concent rations than brook trout.

Forest Songbirds (Paper 16)

• Hg concentrations in blood ranged from 0.10 to 0.80 ppm and were highest in the Bicknell’s thrush (BT).
• Hg content in feathers ranged from 0.10 to
  1.60 ppm and was highest in BT.
• Blood Hg levels were highest in the western mountains of Maine and southernmost Quebec, and lowest in t he Gaspe Peninsula of Quebec.
• Average feat her Hg levels in BT were highest in birds >2 yrs.
• Average blood Hg levels in BT were higher in their wintering grounds.
• All four bird species showed MeHg to Hg ratios of 1:1.

Mink & Otter (Paper 19)

• The average Hg concent rations in mink liver ranged from 1.01 to 3.01 ppm.
• The highest levels occurred in Massachusetts and Connecticut.
• Average Hg levels in river otter liver ranged from 0.85 to 2.10 ppm.
• There was no clear regional pattern for otter Hg.
• 36% of t he mink and otter had levels of Hg in fur that exceeded the adverse effects threshold of 20 ppm.
• The maximum Hg levels in mink and otter fur exceed the acute toxicity thresholds.
• Hg in the liver of otters decreased approximately 26% between 1982–1984 and 1998–2000.
• Hg in mink liver declined roughly 37% between 1982–1984 and 1998–2000.