Analysis of trace elements in air-borne particulates, by neutron activation and gamma-ray spectometry

Abstract

Neutron activation provides a direct method for the analysis of trace elements in air-borne paniculate material collected on filters. Py means of γ-ray spectrometry and utilizing computer techniques the elements sodium, manganese chlorine, vanadium, aluminium, bromine and possibly copper and indium may be determined simultaneously. A number of filter materials have been analysed for interfering trace elements. Teflon (P.T.F.E.) filters are found to have particularly low chlorine concentration in comparison with other materials examined. The esparto grass filters currently used at the nuclear weapon fallout sampling stations operated by A.E.R.E. Harwell, have high trace impurity concentrations. Nevertheless the volume of air filtered is so large that it was found possible to carry out a series of measurements using samples from these stations. Weekly samples from Chilton (Berks.), Lerwick (Shetland), and Milford Haven (Pembs.) have been collected and analysed over periods of several months. Mean concentrations (μg m −3) at Chilton for the year April 1965 to March 1966 were chlorine 2.2, manganese 0.033, sodium 0.85, aluminium 0.25, bromine 0.040 and vanadium 0.015. A small number of daily samples from Salford (Lancs.) indicate concentrations 2–10 times higher than those from Chilton.