Introduction
Snow accumulation during the winter months can create unsafe driving conditions. The use of road salt to deice roads and other surfaces such as sidewalks is a method used to promote safe motor vehicle and pedestrian travel. According to the Salt Institute, the total number of accidents is eight times higher before deicing than after deicing on a two-lane roadway (Madison DPI 2000 road salt report). The most commonly used deicing salt is sodium chloride (NaCl), which is readily available and inexpensive and effective. Wisconsin has a Road Weather Information System that provides highway maintenance managers with information about how much salt should be used on the roads. Previously the managers had to guess how much they should use. This system has helped highway maintenance managers become more proficient and economical in terms of how much salt is used (Wisconsin Department of Transportation 2003-04). Today, salt is a necessary and generally accepted part of the winter environment; however, many do not think of the negative impacts that the salt has. According to a 1991 Lake Wingra study, road salt causes corrosion worth 3.5-7 billion per year in the U.S. The average amount of salt used on road ways is about 250 tons per year in the Lake Wingra watershed in the last decade (lakewingra.org). Those 250 tons become an environmental issue when the ice/snow melts because the water than soaks in the groundwater and into storm sewers into lakes/streams. Approximately 45% of road salt will be carried away overland and flow into lakes or streams, while 55% is absorbed in the shallow aquifer below the surface and slowly moves to contaminate groundwater and habitat around (Madison DPI 2000 road salt report). Knowing that there can be a negative impact on the soil, Lake Wingra, and its habitat, we studied how the road salt is distributed in the soil around Edgewood College, relative to distance from the curb. We also studied chloride levels at different soil depths. In order to do this we tested the conductivity of soil samples and the chloride levels within the soil samples. We believe the deeper levels farther from the curb will have the greater chloride and conductivity levels because we think that as the salt soaks into the soil it will become farther from the curb.