A fluvial mercury budget for Lake Ontario

Joseph S. Denkenberger, Charles T. Driscoll, Edward Mason, Brian Branfireun, Ashley Warnock

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Watershed mercury (Hg) flux was calculated for ten inflowing rivers and the outlet for Lake Ontario using empirical measurements from two independent field-sampling programs. Total Hg (THg) flux for nine study watersheds that directly drain into the lake ranged from 0.2 kg/yr to 13 kg/yr, with the dominant fluvial THg load from the Niagara River at 154 kg/yr. THg loss at the outlet (St. Lawrence River) was 68 kg/yr and has declined approximately 40% over the past decade. Fluvial Hg inputs largely (62%) occur in the dissolved fraction and are similar to estimates of atmospheric Hg inputs. Fluvial mass balances suggest strong in-lake retention of particulate Hg inputs (99%), compared to dissolved total Hg (45%) and methyl Hg (22%) fractions. Wetland land cover is a good predictor of methyl Hg yield for Lake Ontario watersheds. Sediment deposition studies, coupled atmospheric and fluvial Hg fluxes, and a comparison of this work with previous measurements indicate that Lake Ontario is a net sink of Hg inputs and not at steady state likely because of recent decreases in point source inputs and atmospheric Hg deposition.

Original languageEnglish (US)
Pages (from-to)6107-6114
Number of pages8
JournalEnvironmental Science and Technology
Volume48
Issue number11
DOIs
StatePublished - Jun 3 2014

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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