Potentially Toxic Elements (PTEs) distribution and main geochemical processes in Sabato river catchment basin (Southern Italy): a focus on cadmium

The Sabato river (~50 km) is located in a large industrial and urbanized area of the Campania region (Southern Italy), between the cities of Avellino and Benevento. Thus, a study on the distribution of Potentially Toxic Elements (PTEs) and their potential sources was done. Here, we focused on the particular behavior of Cadmium. Firstly, we compared the raw geochemical dataset and the log-ratio (clr) transformed one, found that the latter can improve the readability of the Cd data distribution. Applying a linear regression between the clr-values and the log-transformed cumulative area (estimated by the sample catchment basin approach), we emphasized a possible contaminant source at the headwaters followed by a decreasing trend, potentially explained by a downstream dilution effect. Since there is no evidence of any Cd-related industrial activity at the headwaters, and anomalies seem to be highly localized in the southern part of the basin, we supposed that its main source could be found in the use of some phosphate fertilizers for local agricultural practice.