IDENTIFYING METALLIC CONTAMINANTS OF CONCERN IN THE BREATHING ZONE USING X-RAY FLUORESCENT SPECTROSCOPY (XRF)

Human health risks from the inhalation of metallic dust particles are assessed using exposure rates and frequencies, toxicological parameters of the metals of concern, and most importantly good air-quality data. This study emphasizes the importance of the quick collection in the field of reliable air-quality data using a non-destructive analytical method.

Samples were collected by the Ohio Environmental Protection Agency (OEPA) Northeast District Office (NEDO) using air-quality monitoring equipment at sites adjacent to potential sources of industrial dust. The equipment pulls ambient air through filter cloths, traps particulates, and dries the sample. Each filter cloth was divided into two parts: one part was analyzed by methods that, by design, digest the sample -- thereby destroying it. The remaining part was saved intact and archived. The OEPA loaned our research team the archived cloths, which after our analysis are being returned unaltered.

We used a portable, hand-held x-ray fluorescence spectrometer (XRF) to analyze the metals on the archived cloths. The generated XRF spectra comprise a series of peaks whose x-axis coordinates are in thousands of electron volts (KeV), which identify each metallic element. XRF analysis was useful in screening the samples for metals of concern because the method uses samples that: (1) are not destroyed in the elemental analysis, but rather can be archived for future reference; (2) can be analyzed without time consuming sample preparation; (3) can be analyzed in the field with our portable, hand-held unit; (4) have an analytical turn-around time of a matter of minutes, and (5) thereby, can be reanalyzed immediately if the results warrant.