PRELIMINARY RESULTS OF HEAVY METAL CONCENTRATIONS IN DIFFERENT SIZE FRACTIONS OF URBAN SOILS, JERSEY CITY, NJ

Heavy metal contents of urban soils are commonly used to evaluate surface environmental quality. The level of heavy metal contamination in soils and their potential health effects are often assessed by comparing the measured concentration with those of the guideline value, where the heavy metal concentrations were determined in their bulk size fraction (< 2 mm). However, it has been well established that particle size distribution of soil samples play a significant role not only in the loading of the heavy metals but also in their bioavailability.

Extensive urbanization and industrialization in Jersey City have resulted in the degradation of environmental quality since the beginning of the 19^th century. In this study, we determined the heavy metal contents of urban soils (surface samples) from Jersey City, NJ in both bulk (< 2 mm) and fine (< 63µm) size fractions. We utilized a portable handheld pXRF (NITON XL3t) to determine As, Pb, Zn, Fe and Mn concentrations in the soils. The data was validated by using several standard reference materials including SRM-2710a and SRM-2711a. Particle size distribution of the soil samples were also determined to assess the loading distribution of the heavy metals. The preliminary results of this study reveal that heavy metal concentrations in fine size fraction are statistically higher than those in bulk size fraction with 95% confidence level. The level of enrichment of heavy metal in the fine size fraction compared to those in the bulk size (Element_i in <63 µm / Element_i in < 2 mm) varied from 1.1 to 5.6 depending on the sample location and type of elements. Among the analyzed elements, level of Zn enrichment in fine size fraction (range: 1.6 -5.6) is the highest in all sample locations, which is followed by Pb (1.4 - 4.1), As (range: 1.3 - 3.2), Mn (1.1 - 2.2) and Fe (1.3 - 1.9).