EVALUATING IMPACTS OF ANTHROPOGENIC SALT INFLUXES TO CONNECTICUT'S GROUNDWATER THROUGH WATER QUALITY MONITORING AND TRACER STUDIES

The use of salt as a chemical-deicer has been a widespread practice beginning in the mid 20^th century. Recent efforts to reduce runoff through enhancing infiltration, while effective in their purpose, may be amplifying impacts of chloride contamination. To evaluate these impacts we are developing a series of maps which incorporate water quality data ranging from 1895 to the present. These maps reveal a trend of increasing chloride concentration in Connecticut’s groundwater from an average of 2 mg/L in 1895 to 44mg/L at present. Elevated chloride concentrations can be observed not only in overburden aquifers, but also fractured crystalline bedrock. Spatial and temporal trends in chloride concentration permit correlations with major roads, urban development, salt storage facilities, population growth, and land use changes. To assist in evaluating impacts resulting from the large influx of salt to the environment we are conducting water quality monitoring in conjunction with several salt tracer tests. We will install electrical conductivity meters beneath the University of Connecticut motor pool, and beneath a heavily salted bus and pedestrian route. The data gathered from this field work will allow us to produce estimates of the impacts contributed from runoff, the rate at which salt impacts the water table, and the duration of this impact. The monitoring will also allow us to approximate the degree to which salt contamination is transmitted from the overburden to the fractured crystalline rock. Additionally we will be able to use the water quality monitoring data to determine the rates of fluxes in fractured rock as well as predict trends of long term salt accumulation.