HEAVY METAL IN SURFACE SOIL: AN EXAMPLE FROM TERRE HAUTE, INDIANA, U.S.A

The presence of heavy metals in the environment continues to be of much interest due to the potential impacts on human health. In order to study heavy metal distribution, a pilot study was undertaken to evaluate elemental concentrations in a local park. The study area, located within Fairbanks Park, is a popular recreational area in Terre Haute, IN, which is known for historically heavy traffic and industry. The park is bounded to the east by a road and to the west by the Wabash River. Approximately 80 surface soil samples were collected in a 100 m2 portion of the park. Samples were collected along eight north-south transects spanning the area near the road and near the river. Soil samples were sieved, ashed, and reacted with 2M HCl. Elemental concentrations of Pb, Zn, Co, and Cd were determined using ICP-AES. The initial results show that heavy metal concentrations are higher in the interior of the park and near the road than immediately adjacent to the Wabash River. For example, maximum Pb concentrations of 900 ug/g or higher were found in samples collected from the transect parallel to the road while the Pb concentrations for the transect parallel to the Wabash River average only 7 ug/g. All Cd concentrations are below the instrumental detection limit, except for the two transects nearest the road. Average Zn concentrations for all transects is uniformly high relative to typical background levels throughout the park, except near the river. Almost all Cu concentrations are at or near typical background levels; however, values near the Wabash River average approximately half the values found elsewhere in the park. These results support the importance of roadway sources of heavy metals to the park area.