FACTOR-ANALYSIS OF ATMOSPHERIC TRACE-ELEMENT DEPOSITION DATA IN THE NETHERLANDS OBTAINED BY MOSS MONITORING

Monte Carlo-Assisted Factor Analysis has been applied to a data set of trace element concentrations in samples of the moss species Pleurozium schreberi, collected in 1992 from 66 locations in the Netherlands. A Monte Carlo approach was used to give more insight in the uncertainties and significance levels of the factor analysis results. Using a selection of 23 elements, factor analysis enabled the identification of 8 significant pollution source types. Two source types were assumed to be related to the influence of foliar leaching from higher plants. The remaining source types were found to correspond with the major source types obtained in earlier biomonitoring surveys in the Netherlands using lichen and bark, i.e. crustal material, sea aerosol and various types of industrial pollution sources, associated with metallurgical industries, refuse incineration and oil combustion or processing of oil products. The contribution of the industrial pollution sources appeared to have decreased between 1987 and 1992.