Topical Application of Phosphate Amendments to Lead-Contaminated Small Arms Firing Range Soils

Abstract

Abstract : Because of the need for lead containment within small arms firing range (SAFR) impact areas, phosphate amendment has been proposed to reduce the release of lead via the surface and groundwater pathway. Both field and laboratory studies have evaluated the use of phosphates to stabilize lead in SAFR soils. The main goal of these studies was to determine the effectiveness of in situ phosphate treatment by demonstrating that phosphate addition to lead-contaminated soils resulted in soils that were stable to lead- leaching as measured by various standards. Because these studies were conducted using either large- or small-scale field demonstration projects or static laboratory procedures that were not capable of simulating conditions on actual ranges, their predictive value is limited. Prior to expending operational finds for large-scale soil amendment projects, further evaluation of the effectiveness of lead containment using phosphate amendment in a more realistic system is needed. This study evaluated the performance of two phosphate amendments in a more open dynamic system that simulated field conditions at SAFRs. The results of previous laboratory studies were extended by measuring and comparing losses of both soluble and insoluble lead in leachate and runoff from a treated and untreated SAFR soil using specially designed berm lysimeters. A rainfall simulation technique with the capability of increasing rainfall intensity and varying rainfall duration was developed to evaluate lead migration pathways at SAFRs.