Multivariate analysis of the spatial patterns of 8 trace elements using the French soil monitoring network data

Geostatistical and spatially constrained multivariate analysis methods (MULTISPATI-PCA) have been applied at the scale of France to differentiate the influence of natural background from the pollution due to human activities on the content of 8 trace elements in the topsoil. The results of MULTISPATI-PCA evidence strong spatial structures attributed to different natural and artificial processes. The first axis can be interpreted as an axis of global richness in trace elements. Axis 2 reflects geochemical anomalies in Tl and Pb. Axis 3 exhibits on one hand natural pedogeogenic anomalies and on the other hand, it shows high values attributable to anthropogenic contamination. Finally, axis 4 is driven by anthropogenic copper contamination. At the French territory scale, we show that the main factors controlling trace elements distribution in the topsoil are soil texture, variations in parent material geology and weathering, and various anthropogenic sources.