Sampling the Soils Around a Residence Containing Lead-Based Paints: An X-ray Fluorescence Experiment

Abstract

Sampling experiments utilizing field portable instruments are instructional since students collect data following regulatory protocols, evaluate it, and begin to recognize their civic responsibilities upon collecting useful data. A lead-in-soil experiment educated students on a prevalent exposure pathway. The experimental site was a pre-1950 construction known to have lead-based paint. Soil sampling occurred at multiple locations within the house dripline and a background sample was selected away from the house. Student teams sampled in situ following U.S. EPA Method 6200. Students obtained data quickly with an X-ray fluorescence (XRF) instrument and recognized the importance of sampling. A risk assessment was inherent to the experiment because the XRF generates X-rays. A more than five fold increase in soil lead content for dripline samples was observed relative to the background. Students reported their data and provided advice on methods to minimize contact with this soil to the homeowner. This sampling lab was a valuable general science lab and could be adapted for environmental chemistry and instrumental analysis courses.