EVALUATING PRE-EXISTING SOIL CONDITIONS AT A REHABILITATED COMMUNITY GARDEN LOCATION ON THE WEST SIDE OF SAN ANTONIO, TEXAS

St. Mary’s University, a four-year Catholic liberal arts university located in a mixed residential/commercial area on the westside of San Antonio, TX recently started a campus Community Garden as part of a broader effort to improve campus-wide sustainability. Previously, the site had been maintained as a garden by one of the members of the Society of Mary, but the site had fallen into disuse following his passing. In an urban setting such as the St. Mary’s campus, however, many anthropogenic factors can contaminate soil; if harmful elements are in the garden it can be detrimental to the health of the community. Prior to the rehabilitation of the existing site, soil samples were collected for heavy metal analysis from the 19 raised beds being utilized for the new garden. A NITON XL3t 500 Handheld XRF Analyzer was used for an initial analysis of bulk soil samples. The soils are dominated by Ca, Fe, and K, with measurable levels of other metals such as Pb, Cu, and Zn, although the latter were well below protective limits established by the Texas Commission on Environmental Quality. To develop more homogeneous samples, and to improve analytical precision, each sample was dried, disaggregated, split, and sieved into two size fractions (> 125 μm and < 125 μm). These samples were then loaded into Teflon sample rounds for analysis using the portable XRF analyzer. The XRF results provided information for what is necessary to mitigate the soil chemistry of the garden, whether it would be by conditioning the soil using amendments or clean fill, or removing the soil in each plot.