Determination of Spatial Continuity of Soil Lead Levels in an Urban Residential Neighborhood

This study uses geostatistical techniques to model and estimate soil lead levels in an urban, residential neighborhood. Sixty-two composite soil samples (median 1773 ppm; range 175 to 7953 ppm) in a four-block area of brick and stone homes were obtained. The spatial continuity of soil lead levels was modeled with a semi-variogram, which was then used to estimate lead levels at unsampled locations, a process called kriging. Because soil lead levels were spatially correlated, it is likely that a “nonrandom” process generated the lead distribution found. This finding signifies the existence of lead sources which were tentatively identified on historical maps of the area and from past traffic volume patterns. The distribution of kriged estimates of soil lead levels provides an explanatory tool for exploring and identifying potential sources and may be useful for targeting urban soil abatement efforts.