HEAVY METAL ACCUMULATION ALONG THE PALISADES INTERSTATE PARKWAY, NJ

Roadside soils are major sinks for heavy metals released from automobile traffic through emissions and mechanical wear. In heavily urbanized regions such as the New York / New Jersey Metropolitan Area these contaminants may be remobilized by during road construction or by stormwater runoff. This study examines heavy metal accumulation along the Palisades Interstate Parkway (PIP) and the adjacent Route 9W. This area was chosen due to its history rooted in conservation. The Palisades Interstate Parkway was constructed between 1947 and 1958 on land gifted by John D. Rockefeller. Photographs of the PIP construction suggest that no outside fill was used and only local materials were used in construction and landscaping. Rockefeller’s stipulation that the land surrounding the parkway be restricted to public park use creates a unique opportunity to study roadside metal enrichment in an area without interference from other industrial activities. This study examines metal concentrations and physicochemical characteristics at 3 roadside locations relative to a distal site within a nature preserve located > 0.5 miles away from the road, and relative to the soil’s parent material, the Palisades Sill. Soil cores were taken at 0, 1, 2, 5, and 10 meters from the roadway. The surficial pH (6.13 to 7.16), organic carbon content (4.89 to 14.0%), and moisture content (8.22 to 19.2%) are typical for urban soils. Electrical Conductivity is high at the roadside (572 to 791 μS/cm) suggesting a greater concentration of dissolved solids than in the nature preserve soil (160 μS/cm). Pb and Cr are present in the 10s to 100s of ppm levels. As and Cu are also present. Metals concentrations decrease with distance from the roadside. Data collected from this study will aid in the goal of determining risk of metal exposure from modern and legacy traffic contaminants, and establishing a remediation strategy capable of handling the observed metal loads.