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Two hummock cores (separated by 1 m), two hollow cores (separated by 1 m and both within 5 m of the hummock) from ombrotrophic Big Heath, and a single core from Sargent Mountain Pond (12 km north-northeast of the bog), Mt. Desert Island, Acadia National Park Maine, USA were collected in 1983 and dated using Pb-210 and analyzed for a suite of major and trace metals. The hummock cores correspond closely in terms of dating profiles, concentrations of Hg and Pb, and thus trends and values for accumulation rates. The hollow cores agree generally with each other but give more subdued peaks in concentration and lower integrated anthropogenic burdens of Hg and Pb and 50% lower unsupported Pb-210 than the hummock cores. Sigma(210)Pb(uns.) (Bq/cm(2)), Sigma Hg-anth. (ng/cm(2)), and Sigma Pb-anth. (mu g/cm(2)) for the two hummock cores were 0.744 and 0.773, congruent to 130 and 130 (ng/cm(2)), and congruent to 159 and 138 (mu g/cm(2)), respectively. The values for Sargent Mountain Pond were 0.411, 269, and 72, respectively. Hummock cores agree closely with the lake sediment core with respect to timing of maximum accumulation rates which occurred in the 1970s;

Background atmospheric deposition rates of Hg and Pb to coastal Maine appear to have been about 2.5 to 3 ng/cm(2)/yr and <0.2 mu g/cm(2)/yr, respectively. Atmospheric deposition of Hg acid Pb increased to as much as 20 ng/cm(2)/yr and 2 mu g/cm(2)/yr, respectively, by the 1970s and has decreased since then. Probably more than 50% of the Hg and Pb are deposited in dry and occult deposition.