Geoenvironmental Site Characterization to Treatment: Lead Contaminated Firing Range Case Study

The methodologies employed and the results obtained during the performance of a comprehensive geoenvironmental site characterization case study are presented. The study demonstrates the need to integrate research tools from various disciplines including geotechnical, analytical and mineralogical specialties in order to develop a thorough understanding of both the nature and extent of the environmental issues associated with the site and the most viable alternatives for its remediation. Particle size distribution coupled with contaminant fractionation studies and mineralogical and micromorphological analyses were performed on the soil samples collected onsite to identify the metals present, their concentrations and the mechanisms of transformation. Lead fragments found in the soil samples were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Quantitative phase analysis studies showed that the fine soil fractions contained considerable amounts of lead carbonates, which owing to their colloidal nature could not be readily removed using gravitational methods. To mitigate this deficiency, a bench-scale chemical treatment experiment based on dissolution of the Pb was performed. Although the study is still in progress, the benefits derived from using the multi-disciplinary approach for site characterization described herein warrant consideration by others who may face similar challenges in the future