Hydrochemical, isotopic and microbiota characterization of telese mineral waters (Southern Italy).

The study deals with the analyses of springs and wells at the base of Montepugliano Hill that represents the SE edge of the wide carbonate Matese massif (Campania, southern Italy). At the base of the hill, from west to east and for almost one kilometre, cold springs HCO3-Ca type (Grassano springs, ~ 4.5 m3/s; TDS: about 0.45 g/L) pass to hypothermal, HCO3-Ca type, sulphurous and CO2-rich springs (~ 1 m3/s with TDS > 1 g/L). Some of the latter are widely used in Telese Spa and Centro Relax Spa. Chemical and isotopic analyses carried out for this study support the hypothesis that all these waters (mineral and non-mineral) have the same catchment area, which is located in the Matese massif. As regards the sulphurous springs, they receive both meteoric waters infiltration and uprising of deeper waters rich in endogenous CO2 and H2S gases through important faults systems. Far from these faults, the chemistry of groundwater is scarcely (or not at all) affected by these deep fluid enrichment processes. This scheme is very significant; in fact, when very important groundwater resources are present, it is possible to use both mineral waters in Spa and, in areas far from the faults, those not yet mineralized. Finally, at Montepugliano Hill, in the final stage of the flow path, groundwater is also affected by change in the microbiome: this could provide a basis for comparison between various mineral waters.

Characterization of the analytical performance of δ15 N and δ18 O measurements by the silver nitrate method in the framework of nitrate source apportioning.

RATIONALE: Nitrate pollution represents one of the most important issues for ground and surface water quality and source identification is essential for developing effective mitigation practices. Nitrate isotopic fingerprinting can be utilized to identify the sources of nitrate pollution in aquifers. However, it is crucial to assess the performances (precision and accuracy) of the analytical procedure applied to measure the δ15 N and δ18 O values of nitrates from field samples to correctly apply this tool. METHODS: Nitrates were extracted from a large number of KNO3 samples using the AgNO3 method, and the δ15 N and δ18 O values of these nitrate extracts were measured by isotope ratio mass spectrometry. The availability of this dataset, comprising 693 unprocessed quality control (QC) KNO3 samples and 618 processed samples, allowed us to rigorously quantify the performance of the procedures employed. A salt doping experiment was also performed from which the effects of contaminants on the performance of the method could be ascertained. RESULTS: The overall instrumental reproducibility for the analysis of unprocessed QC samples was 0.5‰ and 2‰ for δ15 N and δ18 O values, respectively, and a strict dependence on signal amplitude was observed. No isotope fractionation was reported for reference samples that were processed according to the "identical treatment" principle (ITP) but normalized by unprocessed reference materials. A significant increase in the standard deviation (SD) was, however, observed compared with that for unprocessed samples. The SD of the processed QC samples allowed us to quantify the reproducibility of the entire procedure as 0.6‰ and 1.0‰ for δ15 N and δ18 O values, respectively. This was comparable with the system reproducibility when normalization using processed reference materials was applied according to the ITP. CONCLUSIONS: Normalization with processed standards is essential to achieve high-precision measurements of the δ15 N and δ18 O values of nitrates extracted from unknown samples. This procedure allowed good accuracy to be guaranteed, and precision levels comparable with the observed instrumental performance to be achieved. A salt doping experiment showed a significant influence of the SO4 2- content on the δ15 N values.

[Water and suspended matter sampling in fresh water networks]. / Il campionamento di acque e particolato in sospensione in sistemi di acque dolci.

Metals and radionuclides in water systems can be easily adsorbed on suspended matter and, finally, they could eventually accumulate in the aquatic environment. The assessment of the health of a water body needs also sampling of the suspended matter fraction. In this paper sampling systems to characterise contaminants associated with the suspended matter fraction are described, with a particular attention to the collection and preservation of samples. Sampling must be representative, to obtain reliable conclusions. In this context it is stressed the importance of the evaluation of the sampling uncertainty, which contributes to a large extent to the total uncertainty.

Characterisation of a reference site for quantifying uncertainties related to soil sampling.

The paper reports a methodology adopted to face problems related to quality assurance in soil sampling. The SOILSAMP project, funded by the Environmental Protection Agency of Italy (APAT), is aimed at (i) establishing protocols for soil sampling in different environments; (ii) assessing uncertainties associated with different soil sampling methods in order to select the "fit-for-purpose" method; (iii) qualifying, in term of trace elements spatial variability, a reference site for national and international inter-comparison exercises. Preliminary results and considerations are illustrated.