COMMUNITY OUTREACH IN GEOSCIENCE: TESTING ORGANIC FARM SOIL FOR HEAVY METAL CONTAMINATION

With urban and organic farming becoming more prevalent it is essential for farmers to know what is in their soil. Metals such as arsenic and lead have well established toxicity when ingested in quantities as low as 2mg/kg of As and 50mg/kg of Pb. In this study samples were collected from 15 private farms and gardens across New England in collaboration in Northeast Organic Farmers Association(NOFA). Samples were analyzed using an X-ray Fluorescence Spectrometer(XRF) to identify the concentrations of As, Pb, Cd, and Hg. Concentrations of the target metals range as follows; Pb 1.3mg/kg - 1729 mg/kg, As 2.9 mg/kg - 106 mg/kg, Pb, when detectible, 3.8 mg/kg - 16.3 mg/kg and Cd, when detectible, 9mg/kg – 23mg/kg. Metal concentrations were spatially analyzed using ArcGIS a geographic information system. Results of the analysis were given to the farmers. Informational packets on what the results potentially mean for their crops, and suggestions for potential mitigation for plot with high concentrations of heavy metals were also provided.