Airborne and Dermal Collection Methods of Gunshot Residue for Toxicity Studies

Abstract

Gunshot residue (GSR) has potential negative health effects on humans as a result of inhalation and dermal exposure to the chemical and physical characteristics of GSR such as Pb, Sb, Ba, nitrocellulose, nitroglycerine, and particulate size fraction. Filter (size selective) and double-sided tape (non-size selective) samples collected airborne GSR during single and triple firing of a 0.22 caliber revolver. Dermal exposures were considered using hand swabs and de-leading wipes, designed to remove the heavy metals. The samples underwent analysis to investigate physical (morphology, size distribution, zeta potential), chemical (black carbon and element concentrations), and potential to induce oxidative stress (oxidative potential via the dithiothreitol (DTT) assay). All sample types detected Pb concentrations higher than national ambient air standards. The de-leading wipes reduced the metal content on the hands of the shooter for Pb (15.57 ± 12.99 ppb and 3.13 ± 4.95 ppb). Filter samples provided health relevant data for airborne PM2.5 for all of the analysis methods except for GSR morphology. This work identified collection and analysis methods for GSR in an outdoor setting, providing protocols and considerations for future toxicological studies related to inhalation and dermal exposures to particulate GSR. Future studies should investigate the influence of meteorological factors on GSR exposure in an outdoor setting.