Start |Author Index | View Uploaded Presentations | Meeting Information

Northeastern Section - 36th Annual Meeting (March 12-14, 2001)

Paper No. 5
Presentation Time: 9:50 AM

LINKED BEHAVIOR OF MERCURY AND ORGANIC CARBON TRANSPORT IN AN UPLAND LANDSCAPE DURING SNOWMELT


SHANLEY, James B.1, SCHUSTER, Paul F.2, REDDY, Michael M.3, ROTH, David A.2, TAYLOR, Howard E.2 and AIKEN, George R.2, (1)U.S. Geological Survey, Water Rscs Div, U.S. Post Office and Courthouse, Room 330, Montpelier, VT 05601, (2)U.S. Geological Survey, Water Rscs Div, 3215 Marine Street, Suite E-127, Boulder, CO 80303, (3)U.S. Geological Survey, Water Rscs Div, PO Box 25046, Denver Federal Center, MS 418, Denver, CO 80225, mmreddy@usgs.gov

We investigated the transport dynamics of dissolved and particulate fractions of both mercury (Hg) and organic carbon during the spring 2000 snowmelt in 10 forested and pastured watersheds (2 ha to 111 km2) at Sleepers River, Vermont. Samples were filtered and preserved on-site within 4 hours of collection using ultraclean handling protocols and double-distilled acid. Mercury determination of duplicates by cold-vapor atomic fluorescence spectrometry (n=65) yielded a precision of +/- 6%. Despite a 6-order-of-magnitude lower concentration, dissolved and particulate Hg concentrations tracked variations in the respective dissolved and particulate carbon fractions remarkably close at each site. Significant positive correlations between Hg and carbon also existed when data were pooled from the 10 watersheds of diverse size, land use, elevation, and slope. Dissolved mercury (HgD) ranged from 0.3 to 2.0 ng/L and correlated strongly with dissolved organic carbon (DOC) in stream water (n=64, r2=0.50, p<.0001). The HgD/DOC ratio increased somewhat through the melt period, suggesting that the available supply of DOC was more easily depleted during sustained high flow conditions. HgD correlated positively with stream specific discharge (n=56, r2=0.46, p<.0001) and inversely with alkalinity (n=64, r2=0.43, p<.0001). Particulate Hg (HgP) ranged from 0.3 to 11.5 ng/L and correlated strongly to particulate organic carbon (POC) (n=63, r2=0.84, p<.0001). HgD and HgP behavior was similar (albeit concentrations were generally lower) to that at other Vermont sites, where episodic export of HgP was found to dominate the streamwater flux. Our results are not definitive as to whether the mobility of Hg and organic carbon are biogeochemically linked, or whether they behave alike simply because they reside in a common reservoir – the surficial organic soil horizon -- which accumulates atmospheric mercury deposition throughout the year and is flushed during snowmelt.

Session No. 23

T7. Geologic Aspects of Environmental Problems in the Northeast
Tuesday, 13 March 2001: 8:15 AM-12:15 PM
Geological Society of America Abstracts with Programs. Vol. 33, No. 1, February 2001
© Copyright 2001 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.
Back to: T7. Geologic Aspects of Environmental Problems in the Northeast
<< Previous Abstract | Next Abstract >>