Use of x-ray fluorescence as a rapid, onsite screening tool in the assessment of cadmium surface contamination

Abstract

Portable x-ray fluorescence (XRF) has successfully been used in the past to quickly and nondestructively evaluate occupational exposure to airborne and surface metal contaminants. Traditional methods of evaluating metal surface contamination involve the costly and time-consuming collection and laboratory analysis of wipe samples, thereby making XRF an attractive method to screen worksites and reduce delays in risk assessment decision making. Existing research into this use of XRF has primarily been centered on the analysis of airborne and surface lead contamination and there is very little literature which examines the use of XRF with other metals. The present study evaluated the use of XRF in the screening of cadmium surface contamination. Wipe samples were collected and screened with XRF prior to being sent to the laboratory for analysis to assess the correlation between XRF semi-quantitative readings in percent mass with laboratory quantitative results in μg/ft2. XRF readings were strongly linearly correlated with laboratory results, as indicated by the R2 value of 0.9929. This linearity of the results demonstrates that with a more sensitive instrument and greater sample size, this is a fruitful avenue for research. The methodology described could be practically used as a screening tool of wipe samples for clearance.