Potentially toxic elements in the soils of Campi Flegrei (south Italy) and the immediate surroundings: Spatial distribution, origin and probabilistic human health risk

Abstract

Campi Flegrei is an active volcanic field in south Italy where the potentially toxic elements (PTEs) are of growing concern because the intensive anthropogenic and volcanic activities might pose adverse human health effects. In this article, 394 topsoils (0–15 cm) are collected for instrumental analysis of the <2 mm fraction. The geochemical maps indicate that higher concentrations of Pb, Zn, Cd, Cr, Hg, Ni and Sb are related to the urban area, but greater levels of As, Tl, Co, Cu, Se and V are observed in the other parts. A robust principal component analysis detected: (1) the Pb–Zn–Hg–Cd–Sb–Cr–Ni association that probably highlights anthropogenic activities such as heavy traffic load and fossil fuel combustion in the urbanized area; (2) the Al–Fe–Mn–Ti–Tl–V–Co–As–U–Th association that mostly reveals the contribution of pyroclastic deposits; and (3) the Na–K–B association that feasibly indicates the weathering degree. The probabilistic health risk modeling for the children under 6 years old shows negligible Pb and Zn non-carcinogenic risk and unexpected Pb carcinogenic risk for exposure through soil ingestion. However, for the inhalation pathway, the children aged <1 year old have the highest chance (90%) of acceptable (i.e. between 1E-6 and 1E-4) Pb carcinogenic health risk. This should not be overlooked because Naples is under high environmental pressure and previous studies reported the increased Pb and Zn quantities in soil over a 26-year timespan. Overall, the results of geostatistical interpolation, compositional data analysis and probabilistic health risk modeling potentially uncover the link between soil geochemistry and human health.