Inorganic contaminants from diffuse pollution in shallow groundwater of the Campanian Plain (Southern Italy). Implications for geochemical survey

Abstract

The Campanian Plain (CP) shallow aquifer (Southern Italy) represents a natural laboratory to validate geochemical methods for differentiating diffuse anthropogenic pollution from natural water-rock interaction processes. The CP is an appropriate study area because of numerous potential anthropogenic pollution vectors including agriculture, animal husbandry, septic/drainage sewage systems, and industry. In order to evaluate the potential for geochemical methods to differentiate various contamination vectors, 538 groundwater wells from the shallow aquifer in Campanian Plain (CP) were sampled. The dataset includes both major and trace elements. Natural water-rock interactions, which primarily depend on local lithology, control the majority of geochemical parameters, including most of the major and trace elements. Using prospective statistical methods in combination with the traditional geochemical techniques, we determined the chemical variables that are enriched by anthropogenic contamination (i.e. NO3, SO4 and U) by using NO3 as the diagnostic variable for detecting polluted groundwater. Synthetic agricultural fertilizers are responsible for the majority of SO4 and U pollution throughout the CP area. Both SO4 and U are present in the groundmass of synthetic fertilizers; the uranium concentration is specifically applicable as a tracer for non-point source agricultural fertilizer contamination. The recognition of non-geological (anthropogenic) inputs of these elements has to be considered in the geochemical investigations of contaminated aquifers.

Geolithological and anthropogenic controls on the hydrochemistry of the Volturno river (Southern Italy)

“…Although the median concentrations for major ions do not differ much among base and peak flow campaigns, maximum values for some ions may vary a lot, with the base flow samples always showing higher values. For instance, maximum NO 3 − and SO 4 2 − concentrations (31.4 and 74.6 mg/l, respectively) were found to be even three times more than the ones of the peak flow samples, suggesting the impact of the anthropogenic activities (Cuoco et al, ) in the plain in the first case and the effect of the discharge of deep mineralized water in the sandstone outcropping area in the latter case (Tables S1 and S2 in supporting information).…”

“…The most abundant cation is Ca 2+ both in the base and in the peak campaigns (median 65.8 and 61.6 mg/L, respectively), followed by were found to be even three times more than the ones of the peak flow samples, suggesting the impact of the anthropogenic activities (Cuoco et al, 2015) in the plain in the first case and the effect of the discharge of deep mineralized water in the sandstone outcropping area in the latter case (Tables S1 and S2 in supporting information).…”

“…The analysis of stream base flow, rainfall, and springs samples used in‐house facilities at the DISTABIF of the Second University of Naples. Major cation and anion analyses were carried out using Dionex ion chromatography (IC) systems (Cuoco et al, ; Jackson, ); a Dionex DX 500 system was used for cation analysis and a Dionex ICS‐2000 system for anion analysis. All samples were filtered through a sterile Millex mixed cellulose esters membrane 0.45 μm HA syringe driven filter units and stored in a 10 ml plastic Dionex ion chromatography vials.…”

“…The analysis of stream base flow, rainfall, and springs samples used in-house facilities at the DISTABIF of the Second University of Naples. Major cation and anion analyses were carried out using Dionex ion chromatography (IC) systems (Cuoco et al, 2015;Jackson, 2000); a Dionex DX 500 sys- Radon-in-air analyzer RAD7 (Durridge Company, USA). The RAD7 analyzer was equipped with the RADH20 kit, for water measurements (Tommasone et al, 2011;De Francesco, Tommasone, Cuoco, & Tedesco, 2010).…”

Simplified two-dimensional modelling to constrain the deep groundwater contribution in a complex mineral water mixing area, Riardo Plain, southern Italy

“…The volcanic aquifer shows a low mineralisation (electrical conductivity (EC) around 350 μS/cm) and HCO 3 -Na, K water type, with a moderate amount of dissolved carbon dioxide (around 200 mg/L; Cuoco et al 2010Cuoco et al , 2015. The mean hydraulic head, measured under static conditions in all wells tapping this aquifer layer, was around 112 m a.s.l.…”