Mercury in snow at Acadia National Park reveals watershed dynamics
Nelson SJ. 2009. Mercury in snow at Acadia National Park reveals watershed dynamics. Park Science. 26(1):35 - 38
Field Work: winter 2004-2005. A brief article, written for non-scientists, on the problem of mercury in snow at Acadia National Park. Following taken from portion of text, under key findings: 'This study generated three major findings. First, the concentration of Hg under conifer forests after snowfall events in winter was similar to that found during the growing season in rain (fig. 2). As with rain throughfall, conifer forested sites had the greatest Hg concentration and deposition, followed by mixed sites, then deciduous sites, and finally nonvegetated sites. This finding differed from results of the few published studies from other sites, which suggested little Hg in snow (e.g., Mason et al. 2000). Second, estimates of Hg in snow throughfall deposition varied by a factor of as much as three, depending on the collection method (fig. 3). When snow bags remained open to the atmosphere all winter, Hg could be emitted from the deposited snow back to the atmosphere. This method provided a low estimate of Hg deposition to watersheds. The closed snow bags collected after each event provided the greatest estimates of Hg flux to watersheds. Previous research at other sites (e.g., Mason et al. 2000) reported relatively low Hg burdens in snow, but their samples were left uncovered, allowing Hg to escape. This research demonstrates that closing collection devices after snowfall events effectively traps Hg. Third, I documented that soils and leaf litter could contribute Hg to the overlying snowpack (fig. 3). I applied a labeled Hg tracer to soils and litter in late autumn. I then sampled the snowpack near the end of winter to determine whether any of the tracer moved vertically up into the snowpack. I recovered the labeled tracer in all the snowpack samples from sites that had been treated, and found greater amounts and percentages of total Hg of the tracer in the bottom portion of snowpack than in the top portion.' /STUDY LOCATIONS:/ /MOUNT DESERT ISLAND/
- Type
- Journal Article
- Authors
- Nelson, Sarah
- Units
- ACAD
- Keywords
- Air, Air Quality, Atmosphere, deposition quality, Dry Deposition, Mercury, Mercury (Hg), Mount Desert Island, Pollution: non-point source, Precipitation, Snow, Water Quality