Soil contamination compositional index: A new approach to quantify contamination demonstrated by assessing compositional source patterns of potentially toxic elements in the Campania Region (Italy)

摘要

Potentially toxic elements (PTEs) are a major worldwide threat to the environment due to the constant global increase in industrial activity and urbanisation. Several studies have provided detailed maps and a better understanding of the spatial distribution patterns of PTEs in different matrices, but the majority of these studies have simply neglected the compositional nature of geochemical data. The aims of this study are to reveal the compositional behaviour and relative structure of 15 PTEs (subcomposition) in Campania, one of the most contaminated regions in Italy, and to quantify the spatial abundance and identify the possible origins of these PTEs. Robust compositional biplots were used to understand the natural grouping and origin of the PTEs. Ratios of specific subcompositions (balances) of PTEs were calculated to map the spatial patterns and identify the spatial variability of the PTEs. This study presents the preliminary steps needed to quantify and analyse the relative difference in the spatial abundance of PTEs by applying a compositional abundance index. In addition, a new soil contamination compositional index (SCCI) was elaborated to quantify topsoil contamination by the 15 PTEs and related subgroups following the compositional structure of the geochemical data.