Use of Neutron Activation Analysis to Determine Arsenic and Antimony Concentrations in Creosote Bushes Collected Near a Lead Smelter in El Paso, Texas

Abstract

El Paso, Texas continues to be a city with environmental concerns particularly for air quality. Both the US Environmental Protection Agency and the Texas Natural Resource Conservation Center have major programs to monitor the unusually high concentration of airborne particles that affect the general population. El Paso, being a border city is also affected by trans border air pollution. One research area that has seen increased visibility involves those industries that can adversely affect both air and soil. Smelters are a prime example of this emissions phenomenon. Typically in the smelting process, arsenic is a natural byproduct of ore processing to extract lead and copper. While processing these ores, arsenic as well as lead, copper, and other elements gain access to the environment through air deposition. Therefore, in areas near smelter activity, arsenic and other heavy metals emissions, can be found and can be a potential serious health concern. Recently the United Nations has proclaimed that as many as 45 million people living in Bangladesh may be at serious health risk from natural contamination of aquifers from arsenic. There have been many published data on elevated concentrations of heavy metals in soil resulting from smelter activities.1–4 Migration of lead from shotgun pellets to humus and plant species at a firing range has also been studied.5 It has been found that some soils adjacent to a lead smelter in El Paso, Texas possess lead and copper concentrations as high as 5,067 mg/kg (parts per million) and 4,955 mg/kg, respectively.6 These concentrations are at least one order of magnitude higher than naturally occurring levels. At present, there are no data reported on the distribution of arsenic concentrations in this area and no information on the uptake of arsenic and antimony by native vegetation. Vegetation may also be an ideal mechanism to bio-remediate soil and can be a natural and inexpensive way to clean up contaminated sites. Therefore, a preliminary investigation into the distribution of the arsenic, its depth in the soil as well as its potential for vegetation uptake would be of great environmental and remediation value. As well, it is known that antimony is a hardener used in lead processing and its determination would also be of value. We report herein the use of neutron activation analysis to determine arsenic and antimony concentrations in creosote bushes and soil samples.