ARE WINTERTIME DE-ICING SALTS HARMING OUR ENVIRONMENT?: THE RESPONSE OF SOIL, QUERCUS RUBRA, AND PINUS STROBUS TO NACL ROCK SALT TREATMENT

Each year, several thousand tons of rock salt are spread on American highways, roads, sidewalks, and porches following winter precipitation storms. When the salt successfully melts the ice and snow, it enters the natural environment in the form of runoff. This study examines the effects on soil quality and tree health by mimicking rock salt runoff in a controlled experiment. Two tree species, the deciduous northern red oak (Quercus rubra) and the coniferous eastern white pine (Pinus strobus) are being sprayed with a 10% NaCl rock salt solution. Monthly soil samples are tested for conductivity, pH, soil moisture content, and concentrations of nitrogen, phosphorous, and potassium (NPK). Tree height is measured bi-weekly and leaf samples are analyzed monthly for chlorophyll content to assess overall tree health. Together, these analyses provide a comprehensive assessment of the impacts of de-icing salts. It is expected that both soil quality and plant health will be negatively affected. With continued application of the rock salt treatment, soil conductivity is expected to increase, while soil moisture and NPK nutrients are expected to decrease. Because soil nutrient and water availability will be limited, the treated trees are expected to experience stunted growth and decreased chlorophyll levels. This experiment has important implications because rock salt is used in large amounts in areas that experience winter precipitation. Although it is effective and inexpensive, its application may lead to unforeseen costs due to losses in ecosystem services.