Development and testing of a new flexible, easily and widely applicable chemical water quality index (CWQI).

Water quality indices (WQIs) are numeric parameters that summarize the overall quality status of freshwaters compared to quality standards by aggregating multiple physicochemical data into a single value. Among the available WQIs in the literature, several criticalities were recognized including: (a) mathematical complexity of the computation, (b) lack of inclusivity, (c) arbitrary weight assignment method, and (d) site-specificity of most of the indexes. The proposed index, the Chemical Water Quality Index (CWQI), aims to overcome these flaws and provides a computation based on simple mathematic equations that are easily manageable on spreadsheet software. The computation is divided into two steps: (i) parametrization of the variables and (ii) index determination. The parametrization consists of assigning a score (s) from ∼1 to 10 to each chemical variable based on (i) measured concentrations and (ii) quality targets (e.g., the limits provided by the European legislation for drinking waters). In the second step, a weight (w), directly proportional to the score (s), is assigned to each parameter, allowing to overcome any bias related to subjective assignments from the user. The resulting CWQI ranges from ∼1 (very good quality) to 10 (extremely poor quality). The reliability and accuracy of the CWQI were assessed by (i) applying the computation to 1,810 waters and (ii) comparing our results with another available WQI. The CWQI outputs showed an optimal response with the number of variables exceeding the quality target with high correlation coefficients (r = 0.94; R2 = 0.89). Due to the simplicity of its computation, the absence of arbitrariness in the weightage of selected variables, and the independence of the proposed approach regarding the choice of the chemical parameters, CWQI can be easily and universally applied.

Contamination Assessment and Temporal Evolution of Nitrates in the Shallow Aquifer of the Metauro River Plain (Adriatic Sea, Italy) after Remediation Actions.

Over the last decades, groundwater resources at global level have suffered a significant deterioration due to nitrate pollution, mainly related to the input of agricultural fertilizers, manure, sewage, and untreated urban and industrial effluents. The most impacted waters are those forming surface and shallow reservoirs, which usually play a key role in supplying waters to civil, agricultural, and industrial activities. The terminal portion of the Metauro River plain, located in central Italy along the Adriatic Sea coastline, hosts a strategic phreatic aquifer that, along with the surface water of the Metauro River, supplies water to the local population (i.e., about 60,000 people). This shallow coastal aquifer experiences a long-lasting story of nitrate contamination since the 1970s when the increase in the use of agricultural fertilizers contributed to very high levels of pollution (NO3- > 100 mg/L). This fact prompted the local authorities to carry out remediation actions that involve a pumping system to inject the NO3--poor waters from the Metauro River course directly into the shallow aquifer. The present work was aimed at defining the contamination of nitrates in this important water resource. The main geochemical characteristics and the temporal evolution of NO3- concentrations (between 2009 and 2020), in the shallow coastal aquifer of the Metauro River plain, were analyzed by means of classical geochemical analyses and multivariate methods accounting for the compositional nature of the data, to assess the efficiency of the in-situ remediation over time.

Could soluble minerals be hazardous to human health? Evidence from fibrous epsomite.

From a toxicological point of view, particulates and fibres with high solubility in water and/or in biological environments have not been considered in detail and the knowledge to date in this area is very scarce. In this study, the water-soluble natural epsomite fibres from Perticara Mine (Italy) were investigated using SEM-EDS, XRPD, ICP-AES and alpha spectrometry measurements which were combined and integrated to characterise the fibres' morphology, crystal chemistry and mineralogy. The morphological and morphometric results showed that most of the fibres are of inhalable size (Dae 5.09 µm) and can be potentially adsorbed from all parts of the respiratory tract. Chemical analysis reveals significant amounts of toxic elements (As, Co, Fe, Mn, Ni, Sr, Ti, Zn) and surprisingly high contents of radioactive isotopes (210Po and 228Th) in epsomite crystals, making the inhalation of these fibres potentially hazardous to human health. Through this study, we want to focus on soluble minerals, such as epsomite, which can be present in both natural and anthropic environments and have never been considered from the point of view of their potential hazard.