Lead in soil - an examination of paired XRF analysis performed in the field and laboratory ICP-AES results

Abstract

A major aspect of lead hazard control is the evaluation of soil lead hazards around housing with lead-based paint applied to specific exterior surfaces. The use of field-portable X-ray fluorescence (FPXRF) to do detailed surveying, with limited laboratory confirmation, can provide lead measurements in soil (especially for planning and monitoring abatement activities) in a more timely manner than laboratory analysis. To date, one obstacle to the acceptance of FPXRF as an approved method of measuring lead in soil has been a lack of correspondence between field and laboratory results. In order to minimize the differences between field and laboratory results, a new protocol has been developed for field drying and sieving of collected samples for field measurement by FPXRF. To evaluate this new protocol, composite samples were collected in the field following both HUD Guidelines and American Society for Testing and Materials (ASTM) protocols, measured after drying and sieving by FPXRF, and returned to the laboratory for confirmatory inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. Evaluation of study data from several diverse sites revealed no statistical difference between paired FPXRF and ICP-AES measurements when samples were dried and sieved to less than 250 µm particle size.