Ongoing Monitoring of Forest Soil Mercury in Vermont, USA


TitleOngoing Monitoring of Forest Soil Mercury in Vermont, USA
Publication TypeConference Paper and Presentation
Year of Publication2017
AuthorsRoss, DS, Shanley, JB, Bailey, S, Villars, T, Quintana, A, Duncan, J
Conference Name13th International Conference on Mercury as a Global Pollutant (ICMGP2017)
Date Published2017/07
Conference LocationProvidence, RI
Abstract

Continued monitoring of total mercury (THg) concentration in soils is
essential for detecting, predicting and addressing environmental change. In cooperation with the Vermont Monitoring Cooperative (now the Forest Ecosystem Monitoring Cooperative), we have established a long-term soil monitoring study in forested sites in the northeastern USA where annual wet deposition of Hg has been in the range of 6-10 μg/m2. Five 50 x 50 m plots were located in protected areas, three on Mt. Mansfield in north-central Vermont and two in the Lye Brook Wilderness Area in southwestern Vermont. Elevation ranges from 590 to 1140 m with forest type changing from typical northern hardwood (Acer saccharum, Betula alleghaniensis and Fagus grandifolia) to high-elevation spruce-fir (Picea rubens and Abies balsamea). Each plot contains 100 5 x 5 m subplots with sampling date assigned randomly (10 per date). The initial sampling
of these plots took place in the summer of 2002 and resampling occurred in 2007 and 2012. Small pits were dug in the center of each plot and the soils were sampled both by genetic horizon and depth increments. These samples have been analyzed for a suite of chemical parameters, including exchangeable cations, carbon and nitrogen. Separate samples of the uppermost humified horizon (Oa or A) were taken for total Hg (THg) analysis using appropriate protocols. Average THg concentration at each site ranged from ~200-500 ng/g. The average carbon concentration in these horizons varied between ~100-420 g/kg. There was a positive elevational gradient of THg concentration, consistent with greater deposition and with other studies. The THg:C ratio (ng/g) ranged from 0.6-1.8, with the highest ratio at the highest elevation. Continued sampling at 5-year intervals will allow detection of environmental change in response to both a changing climate and changing Hg deposition.

URLhttp://mercury2017.com/program/technical-program/p1h/
Status: 
Published
Attributable Grant: 
BREE
Grant Year: 
Year2
Acknowledged VT EPSCoR: 
Ack-Yes