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Granato G.E., Church, P.E., Stone V.J., 1995, Mobilization of Major and Trace Constituents of Highway Runoff in Groundwater Potentially Caused by Deicing-Chemical Migration, Transportation Research Record 1483, Transportation Research Board, National Research Council, Washington D.C., p. 92-104. Mobilization of major and trace constituents of highway runoff in groundwater
potentially caused by deicing-chemical migration is indicated by analyses of groundwater
samples collected at test sites adjacent to Route 25 in southeastern Massachusetts during
February and August 1991 and March, August, and November 1993. Analyses indicate that
concentrations of major and trace chemical constituents of highway runoff in groundwater
are substantially higher downgradient than upgradient from the highway. Highway runoff
containing road salt and calcium-magnesium acetate seems to have the greatest effect on
groundwater quality at one test site where highway runoff discharges locally to the land
surface. This site has an open-drainage system typical of many highways. Analyses from
these five sampling rounds are indicative but not conclusive because additional spatial
and temporal data are needed. However, this information, when combined with 4 years of
monthly groundwater-level measurements and water-quality analysis of groundwater and
highway-runoff samples, show that potential mobilization processes include winter
recharge, effects related to ion exchange, and acidification and mineral weathering caused
by deicing-chemical migration. These processes are hypothesized because 75 percent of
annual recharge occurred during the winter months, sodium was exchanged for calcium in
infiltrating water, and pH decreased significantly in downgradient groundwater. Return to GGRANATO |