Enzyme activity along depth in metal contaminated soils at Liberty State Park

A railroad that once passed through Liberty State Park (Jersey City, NJ) left the soil contaminated with heavy metals. Due to contamination, a section of the park was and remains closed to the public. Sites designated 25R and 25F in the park display similar contamination in the park, but 25F has vegetation while 25R does not. The purpose of this study is to investigate the relationship between enzyme activity and soil depth in these two sites. Soil cores, which maintain the structure of soil along depth, were sampled from both sites. Each core was ten centimeters deep and divided into two-centimeter cross-sections. We determined three enzymatic activities for each cross-section using fluorescence spectroscopy. The levels of phosphatase, cellobiohydrolase, and leucine-amino peptidase activities throughout the soil’s depth were examined for both sites. These enzymes are important for nutrient cycling pathways in the soil, with high enzyme activity indicating high soil function. Preliminary data for site 25R shows little phosphatase and leucine-amino peptidase activity overall and little variation throughout depth, while cellobiohydrolase shows an initial increase that reaches a maximum and then decreases throughout depth. Site 25F maintains higher phosphatase, cellobiohydrolase, and leucine-amino peptidase activity overall and a decreasing trend as deeper portions are examined. The decreased activity may be caused by lack of exposure to the microbes in the air and fewer naturally occurring disturbances in deeper soil. Studying the enzymatic activity of contaminated soil throughout depth will provide insight on a relationship between soil depth and soil functionality in contaminated soils. The relationship may provide a new understanding of how contaminated soil behaves and how it may be improved