APPLICABILITY OF GOLD AS AN ATMOSPHERIC AEROSOL TRACER

The present paper describes a method to determine the gold content of samples of atmospheric particulate matter. Both integral filter sample s as well as size-segregated impactor samples are accessible to the me thod. Results of the analysis of 29 filter samples and three size-segr egated impactor samples, taken at Ispra in Northern Italy, are reporte d. The frequency distribution of the gold concentrations can be descri bed by a log-normal distribution with a geometric mean concentration o f 23.2 pg m(-3) and a geometric standard deviation of 2.1. The method is validated by the analysis of a certified reference material, for wh ich a mean recovery of gold of 78% was obtained. Based on the variabil ity of the gold concentration in atmospheric aerosol, the maximum dist ance to which gold as a tracer can be quantified, assuming specific me teorological conditions, is estimated by means of the Gaussian Dispers ion Model. Using Pasquill Stability Classes to characterize atmospheri c stability, this distance is 33 and 104 km for stability classes C an d D, respectively, for a release of 65 g of gold. References to other tracer experiments are given. (C) 1997 Elsevier Science Ltd.