[en] The analysis of samples by means of X-ray fluorescence spectrometry has been used to monitor environmental pollutants in a collaborative project between the Department of Physics, the Centre for Materials Science of the University of Birmingham and latterly the University of Manitoba. Lead was chosen as the element of greatest environmental interest and the abundance of tree linedroads in the vicinity of the University suggested that leaves would be a convenient sampling medium for the investigation of atmospheric lead concentration in areas of high traffic density. The results indicate that about half of the lead present in the leaves can be removed by washing in a 5% solution of acetic acid. The lead concentrations in the leaves do not appear to be constant for a given species but vary with location and its proximity to traffic routes. The deciduous leaves were about six weeks old when the samples were taken. Broad beams grown in an atmosphere of exhaust fumes absorb a substantial quantity of elemental lead. (T.G.)