Assessing Background Values of Regulated Parameters in Groundwater Bodies of Sardinia (Italy)

Abstract The groundwater bodies in the European Union should be classified on the basis of their chemical status according to the European regulations. To this purpose, the background values for electrical conductivity, chloride, sulfate, fluoride and lead in groundwater bodies hosted in carbonatic rocks in Sardinia (Italy) were estimated. Background values were dependent on geological (lithology and mineralization) and geographical (distance from the coast) features of aquifers. Results indicate that statistical methods should be integrated with hydrogeochemical investigations for a correct assessment of the background values

Geochemistry, stable isotopes and statistic tools to estimate threshold and source of nitrate in groundwater (Sardinia, Italy)

In the European Union, nitrate vulnerable zone (NVZ) should be designed for the mitigation of nitrate (NO3−) contamination caused by agricultural practices. Before establishing new NVZ, the sources of NO3− must be recognized. A geochemical and multiple stable isotopes approach (hydrogen, oxygen, nitrogen, sulfur and boron) and statistical tools were applied to define the geochemical characteristics of groundwater (60 samples), calculate the local NO3− threshold and assess potential sources of NO3− contamination in two study areas (hereafter Northern and Southern), located in a Mediterranean environment (Sardinia, Italy). Results of the integrated approach applied to two case study, permits to highlight the strengths of integrating geochemical and statistical methods to provide nitrate source identification as a reference by decision makers to remediate and mitigate nitrate contamination in groundwater. Hydrogeochemical features in the two study areas were similar: near neutral to slightly alkaline pH, electrical conductivity in the range of 0.3 to 3.9 mS/cm, and chemical composition ranging from Ca-HCO3− at low salinity to Na-Cl− at high salinity. Concentrations of NO3− in groundwater were in the range of 1 to 165 mg/L, whereas the nitrogen reduced species were negligible, except few samples having NH4+ up to 2 mg/L. Threshold values in the studied groundwater samples were between 4.3 and 6.6 mg/L NO3−, which was in agreement with previous estimates in Sardinian groundwater. Values of δ34S and δ18OSO4 of SO42− in groundwater samples indicated different sources of SO42−. Sulfur isotopic features attributed to marine SO42− were consistent with groundwater circulation in marine-derived sediments. Other source of SO42− were recognize due to the oxidation of sulfide minerals, to fertilizers, manure, sewage fields, and SO42− derived from a mix of different sources. Values of δ15N and δ18ONO3 of NO3− in groundwater samples indicated different biogeochemical processes and NO3− sources. Nitrification and volatilization processes might have occurred at very few sites, and denitrification was likely to occur at specific sites. Mixing among various NO3− sources in different proportions might account for the observed NO3− concentrations and the nitrogen isotopic compositions. The SIAR modeling results showed a prevalent NO3− source from sewage/manure. The δ11B signatures in groundwater indicated the manure to be the predominant NO3− source, whereas NO3− from sewage was recognized at few sites. Geographic areas showing either a predominant process or a defined NO3− source where not recognize in the studied groundwater. Results indicate widespread contamination of NO3− in the cultivated plain of both areas. Point sources of contamination, due to agricultural practices and/or inadequate management of livestock and urban wastes, were likely to occur at specific sites

Combining hydrogeochemistry, statistics and explorative mapping to estimate regional threshold values of trace elements in groundwater (Sardinia, Italy)

Assessing geochemical baseline and threshold values of potentially toxic elements at adequate scales is fundamental for distinguishing geogenic contamination from anthropogenic pollution in groundwater. This study was aimed to estimate the regional threshold values of Li, Be, B, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Te, Ba, Hg, Tl, Pb, Bi, and U (elements listed according to atomic numbers) in groundwater, compare results to guidelines established for drinking water and the protection of groundwater from contamination, investigate the geographical distribution of trace elements, and assess the potential influence of water-rock interaction. A pre-selection aimed at excluding groundwater samples affected by known anthropogenic activities was carefully carried out based on hydrogeochemical characteristics of waters and considering the potential sources of contamination. The resulting dataset was comprised of 1227 groundwater sampling sites located in Sardinia (Italy). Undetected values were treated using the Regression on Order Statistics method. For elements containing >75 % of undetected values and/or a limited number of samples in the dataset (Li, Rb, Sr, Mo, Ag, Te, Tl, Sb, Hg and Bi), the threshold values were estimated using either the 95th or 97.7th percentiles. For the other elements the mean + 2SD (Standard Deviation), the median + 2MAD (Median Absolute Deviation), and the TIF (Tukey Inner Fence) estimators were also calculated. Geochemical maps allowed to recognize the threshold value of each element at different scales. Regional threshold values of the regulated elements B, Al, V, Cr, Cu and Cd in groundwater were below the Italian and World Health Organization drinking water guidelines, whereas Mn and As were above them. Regional threshold values estimated with TIF exceeded the drinking water guidelines for Ni, Se, Pb and U. Results of this study showed that high concentrations of trace elements in groundwater were primarily dependent on the corresponding amount in parent materials with which the groundwater came into contact. Physical-chemical parameters and geochemical characteristics may contribute to enhancing concentrations of some trace elements in groundwater, e.g. As via reductive dissolution of Fe(III)-Mn(IV) hydroxides/oxides, Pb via formation of stable aqueous complexes, and other elements via adsorption onto fine particles with size below 0.4 μm (i.e. the pore size of filters used). Maps drawn on the centered log-ratio (clr) transformation of hydrogeochemical data, following the CoDA (Compositional Data Analysis) approach, allowed to pinpoint critical areas to be investigated in more detail. For each geological complex, groundwater samples likely representing nearly pristine conditions were identified. The monitoring of these representative groundwater samples may help to pinpoint eventual changes in environmental conditions

A Methodological Approach For The Effective Infiltration Assessment In A Coastal Groundwater

Accurate estimates of spatial and temporal distribution of groundwater recharge are of utmost importance to protect groundwater systems. In coastal areas, the fragility of the systems makes such estimates critical for the correct management and protection of water resources from saltwater intrusion. The Muravera coastal plain, in the south-eastern Sardinia, has been studied since 1960, due to important saltwater intrusion phenomena. Since the early fifties, the natural hydrodynamic equilibrium between groundwater, surface-water and seawater has been deeply modified by the construction of four dams across the Flumendosa river and the development of agriculture, tourism and aquaculture activities along the coast. To implement an integrated and sustainable management system addressed to slow down the process of saltwater intrusion and, on the other, satisfy human requirements, it is important to develop a flexible scenario analysis system that considers changes of land-use and inputs to the hydrogeological system, also in relation to climate change. In this study, the innovative Soil Water Balance code (SWB) has been applied to the Muravera plain groundwater body to calculate spatial and temporal variations of groundwater recharge. The code calculates the recharge (R) by using geographic system (GIS) data layers in combination with tabular climatological data. It is based on a modified Thornthwaite - Mather soil water balance approach, with components of the soil water balance calculated at a daily time-step. A combined experimental approach of hydrogeological, satellite remote sensing and pedological methodologies has been applied to derive data layers describing local features of: (1) land-use classification, (2) hydrologic soil group, (3) flow direction, and (4) soil-water capacity. The code has proved to be promising for the effective infiltration assessment and it can be easily updated with high resolution data acquired in the field and from satellite images

Active elderly and health-can moderate exercise improve health and wellbeing in older adults? Protocol for a randomized controlled trial

Abstract Background: Aging is marked by a progressive rise in chronic diseases with an impact on social and healthcare costs. Physical activity (PA) may soothe the inconveniences related to chronic diseases, has positive effects on the quality of life and biological rhythms, and can prevent the decline in motor functions and the consequent falls, which are associated with early death and disability in older adults. Methods: We randomized 120 over-65 males and females into groups of similar size and timing and will give each either moderate physical activity or cultural and recreational activities. Being younger than 65 years, inability to participate in physical activity for any medical reason, and involvement in a massive program of physical exercise are the exclusion criteria. The primary outcome measures are quality of life, walking speed, and postural sway. Participants are tested at baseline, post-treatment, and 6-month (24 weeks) and 12-month (48 weeks) follow-ups. Discussion: This study aims at improving the quality of life, wellness, and cognitive functioning in the elderly through a low-cost affordable program of moderate physical activity. Given the growing aging of the world population and the social and economic burden of disability in the elderly, our results might have a major impact on future practices

Some geological and environmental aspects of the Sàrrabus-Gerrei Region (SE Sardinia, Italy)

This paper focus on some geological and environmental aspects of the Sàrrabus-Gerrei region (SE Sardinia, Italy). The first part (leader: Francesco Secchi) is dedicated to the Sàrrabus igneous massif that outcrops over an area of about 400 km2 and is a shallow calcalkaline pluton characterized by multiple intrusions emplaced in the frontal part of a nappe pile at the end of hercynian orogeny. The second part of the trip (leader: Mario Lorrai) is dedicated to the abandoned antimony mine of Su Suergiu (Villasalto, Gerrei) where an important metallurgical activity has been joined with mining works since 1882. In this area, the hydrogeochemical characterization of both ground and surface waters provide useful information about the impact of the past mining activity on the environment

Assessing background values of chloride, sulfate and fluoride in groundwater: A geochemical-statistical approach at a regional scale

The Sardinia island (Italy) is one of the European areas least affected by potentially anthropogenic impacts, such as spreading urbanization, intensive agriculture and regional atmospheric contamination. Such characteristics allow to consider Sardinia a good site for testing an approach that integrates geochemical tools, hierarchical cluster and geographical information system, aimed at estimating background concentrations of chloride, sulfate and fluoride at the regional scale. Analytical data were obtained from several hydrogeochemical surveys and from the groundwater-monitoring program established by the Sardinian Regional Government. Groundwater samples were grouped according to their circulation in the predominant hydrogeologic complex: Quaternary sediments, Quaternary basalts, Tertiary sediments, Tertiary volcanic rocks, Mesozoic carbonatic rocks, Paleozoic carbonatic rocks, granitic rocks and metamorphic rocks. Samples surely affected by anthropogenic inputs, thermal waters, waters collected at wells with unknown construction details and poor quality analyses were excluded. The resulting dataset included 1414 groundwater sampling sites distributed over an area of 24,090 km2 (All data). Another dataset comprised of 641 sampling sites (Selected data) was derived by All data excluding the groundwater with NO3- > 10 mg/L. Hierarchical clustering analysis was performed on both datasets considering Ca2+, Mg2+, Na+, K+, Cl-, HCO3-, SO42-, NO3- and F-. The values of total dissolved solids (TDS) were a major distinguishing factor among clusters, but distinct signatures related to the median nitrate and fluoride concentrations were also recognized. The geographic distribution of clusters reflected the role of geological and geographic characteristics on the geochemistry of groundwater. Background ranges of the regulated parameters chloride, sulfate and fluoride in each cluster, identified either using All data or Selected data, were calculated using the median±2MAD. Although results were found in general agreement, the threshold using the median+2MAD was calculated using the Selected data only, because the Selected data better represents near pristine conditions. Chloride threshold values above the drinking water limit were mainly observed in groundwater located in western Sardinia, where sediments and volcanic rocks prevalently outcrop, and also in some coastal areas. Threshold values of sulfate and fluoride above the limit were related to local conditions. Specifically, high threshold values of sulfate were observed in groundwater interacting with the Tertiary volcanic rocks that host known sulfide mineralization and at sites where evaporitic deposits occur. Threshold values of fluoride above the limit were often observed in the areas where fluoride mineralization occurs. High fluoride values may also result from cation exchange and/or supersaturation with respect to calcite. The results of this study indicate that the integration of hierarchical clustering analysis with the geochemical characteristics of groundwater, also taking into account the geological context, allow the repartition of groundwater samples in distinct hydrogeochemical groups, which in turn allow to calculate the background ranges and reliable threshold values in groundwater. This approach can be applied to assess the background concentrations of chemical parameters at a regional scale when a large dataset is available

Human energy consumption during harvesting of saffron flowers

In this paper the oxygen uptake using a metabolic measurement system and energy cost of a human operator during the harvesting of saffron flowers are discussed. The measurement of energy cost was performed for a traditional harvesting handmade activity compared to a harvesting phase with a facilitator machine. In the paper the facilitator machine prototype is described and its mechanical performances are presented. The metabolic measurements layout and results are then discussed, the test protocols are declared and the measures outlined and discussed comparing the energy cost with and without facilitator machine. For the experimental evaluation of the energy consumption a significant number of measurement samples for a statistically reliable evaluation has been used. A quantity synoptic parameter has been proposed for the comparison of energy consumption with and without the facilitator machine

Long-Term Annual Average Aquifer Recharge assessment for the island of Sardinia (Italy)

Evaluation of Long-Term Annual Average Recharge (LTAAR) is a challenge for sustainable management of groundwaters. Despite many methods were developed based on different kind of input dataset, inverse water balance is one of the most effective approach when long term climatic data series are available. In this work, the inverse water balance for all the aquifers of the Hydrographic District of Sardinia (Arras et al. 2019) is presented. The proposed model adopts a geographically based integrated evaluation system. Daily precipitation and temperatures data from the official weather stations network of Sardinia was collected for the periods 1981-2010 and 2009-2018, while average precipitation and temperature maps, elaborated by the Sardinian Regional Agency for Environmental Protection (ARPAS: Hydro-meteoclimatic Department), were used for the period 1971-2000. Elevation data comes from the 10 m grid Digital Terrain Model (DTM) of Sardinia, downscaled to a 40 meters grid. Daily measurements were used to calculate climate Normal according to the World Meteorological Organization guidelines (WMO 2017). Spatial interpolation of punctual Normal was performed through the application of the ordinary kriging of residuals from linear regression between climatic data and elevation. The method provides good results in terms of accuracy in reproducing missing data for both the climatic dataset, as demonstrated in similar context (Di Piazza et al. 2015). The Turc modified method by Santoro (1970) was used to calculate the actual evapotranspiration term. Based on literature data and field measurements potential infiltration indexes were evaluated. Then, runoff was calculated as difference between effective precipitation and effective annual aquifer recharge. Results have shown that LTAAR for the whole hydrographic district of Sardinia ranges from 1600 (1971-2000) to 1540 (1981-2010) and 1690 (2009-2018) Mm3, representing 15% of the average annual precipitation; more than 65% of the annual available water is lost through evapotranspiration; the remaining 20% occurs as runoff

Methodology for identifying groundwater-dependent ecosystems (GDE) and allowing the groundwater status assessment accordingly in Sardinia.

The Water Framework Directive (WFD; 2000/60/EC) aims to establish a framework for protecting waters. Among the WFD’s objectives, the achievement of a good groundwater status is required, including a good groundwater quantitative and chemical status. The ecosystems directly dependent on groundwater (terrestrial and aquatic GWDE) can affect the status of a groundwater body (GWB), where is causing significant damage to the GDE. In the framework of updating the River basin management plan of Sardinia, a methodological approach for identifying (SWBs) and terrestrial ecosystems directly dependent from GWB has been proposed. In the first step, a priority has been assigned to the SWBs with a “not good” status or being at risk of failing to meet the objectives set for each body under Article 4 according to their characterization (PdG, 2016). Springs and low-lying coastal areas were considered as potential terrestrial ecosystems in Sardinia, as internal wetlands are usually temporary and feed by rain (Bagella et al., 2010). The GIS-based methodology envisages a cross-referencing procedure of various thematisms, according to the following work-flow: 1- Identify fresh perennial, intermittent and ephemeral and transitional SWB according to their “not good” status or being at risk of failing to meet the objectives set for each body under Article 4 (PdG, 2016). 2- Select springs 3- Use the Special Protection Areas (SPAs), Sites of Community Importance (SCIs), and Special Areas of Conservation, SACs; 4- Use the Nature map (Camarda et al, 2015) to identify the Ecological data; 5- Select the groundwater (GW) with poor quantitative status. 6- Establish whether a connection between GWB and SWB occurs on the base of the hydrogeological information. According to the schema, the potential GDE will be identified. Remotely satellite acquired data, morphometric and geological data, and field surveys will mainly support the identification, particularly where hydrogeological information is missing