A multifractal analysis of spatial variability in top soil compositions in the Campanian Region

The spatial distribution of elements in topsoils of the Campanian Region are controlled by a number of factors. Chief among them, geogenic controls based on the geological substrate and the influence of anthropogenic activity.... [ view full abstract ]

The spatial distribution of elements in topsoils of the Campanian Region are controlled by a number of factors. Chief among them, geogenic controls based on the geological substrate and the influence of anthropogenic activity. The Campanian region comprises a diverse range of morphologies and land uses. Over 50% of available land is committed to agriculture and cultivation, while urbanization has claimed ~15% of the region. A total of 3535 soil samples were collected over the 13,593 km2 study area using a 16 km2 grid from suburban and agricultural areas, and a ~4 km2 grid in urban zones. These samples were analysed for 53 elements using LA-ICPMS, and spatial analysis was performed on each element using multifractal methods. Distribution maps were obtained using an IDW algorithm, and applying a Concentration-Area (C-A) filter to discriminate common behaviours in the spatial distribution of elemental concentrations. A Spectrum-Area (S-A) filter was also used in order to separate the baseline values from anomalies.

Most elements were clearly correlated with the underlying Na–K volcanism (e.g., La, Th, Ti, Na, K) and were generally enriched in areas surrounding the Campi Flegrei and Somma–Vesuvius volcanic regions, while Ca, Mg, and Sr were also enriched in the N and NE of the region, where limestones and dolostones dominate the substrate. Enrichments in Co, Cr, and Ni were associated with the flysch deposits of the NE, while clear enrichments in Pb, Cd, P and Cr were found in areas affected by urbanization, agricultural fertilization, and industrialization.