Surveying and localized screening of soil contamination with the growth of urban community agriculture in Northern Utah

Abstract

Abstract Urban soil contamination has become an increasing concern within residential developments and with the expansion of urban agriculture, which has grown across the United States. In Salt Lake County, Utah, there are 39 community gardens and urban farms, with more in development. Only limited data exist to determine whether these soils may be considered contaminated. The purpose of this study was to conduct an urban soil survey in Salt Lake County for initial screening of soils in community gardens and urban farms for common contaminants, including the trace elements lead and arsenic (total concentrations), along with organic contaminant benzo (A) pyrene (BAP). Site selection included an emphasis on sites serving at least nine families and those with greater potential for soil contamination based on identified risk factors. Measured soil test concentrations were compared to US EPA regional screening levels (RSLs) and other US background levels. Lead concentrations ranged from 14.8 to 516 mg kg−1, with a mean concentration of 91.8 mg kg−1. Measured arsenic ranged from 2.83 to 39.3 mg kg−1 with a mean of 11.8 mg kg−1. All measured arsenic concentrations exceeded the US EPA RSL of 0.68 mg kg−1. BAP was the primary hydrocarbon of concern, and concentrations above detectable limits ranged from 0.01 to 0.44 mg kg−1, with a mean concentration of 0.09 mg kg−1. By determining the baseline degree of soil contamination in key urban agricultural sites in Utah's most populated county, local screening levels were developed into soil management plans for producers.