Salinization and nitrate pollution are generally ascertained as the main issues affecting coastal aquifers worldwide. In arid zones, where agricultural activities also result in soil salinization, ...both phenomena tend to co-exist and synergically contribute to alter groundwater quality, with severe negative impacts on human populations and natural ecosystems’ wellbeing. It becomes therefore necessary to understand if and to what extent integrated hydrogeochemical tools can help in distinguishing among possible different salinization and nitrate contamination origins, in order to provide adequate science-based support to local development and environmental protection. The alluvial plain of Bou-Areg (North Morocco) extends over about 190 km
2
and is separated from the Mediterranean Sea by the coastal Lagoon of Nador. Its surface is covered for more than 60% by agricultural activities, although the region has been recently concerned by urban population increase and tourism expansion. All these activities mainly rely on groundwater exploitation and at the same time are the main causes of both aquifer and lagoon water quality degradation. For this reason, it was chosen as a case study representative of the typical situation of coastal aquifers in arid zones worldwide, where a clear identification of salinization and pollution sources is fundamental for the implementation of locally oriented remedies and long-term management strategies. Results of a hydrogeochemical investigation performed between 2009 and 2011 show that the Bou-Areg aquifer presents high salinity (often exceeding 100 mg/L in TDS) due to both natural and anthropogenic processes. The area is also impacted by nitrate contamination, with concentrations generally exceeding the WHO statutory limits for drinking water (50 mg/L) and reaching up to about 300 mg/L, in both the rural and urban/peri-urban areas. The isotopic composition of dissolved nitrates (δ
15
N
NO3
and δ
18
O
NO
) was used to constrain pollution drivers. The results indicate two main origins for human-induced pollution: (i) manure and septic effluents, especially in urban areas, and (ii) synthetic fertilizers in agricultural areas. In the latter, δ
15
N-enriched values highlight a mixture of those sources, possibly related to unbalanced fertilization and agricultural return flow. Boron isotopes (δ
11
B) were hence studied to further distinguish the nitrate origin in the presence of multiple sources and mixing processes. The results indicate that in the study area, the high geochemical background for B and Cl, associated to the complex water-rock interaction processes, limit the application of the coupled δ
11
B and δ
15
N isotopic systematics to the detection of sources of groundwater pollution. In fact, despite the exceedingly high nitrate contents, the depleted δ
11
B values that characterize synthetic fertilizers and sewage leakages could not be detected. Therefore, even if in saline groundwater the anthropogenic contribution has a negligible effect in terms of salinity input, with both sewage and irrigation water not very charged, the associated nitrate content fuels up water-rock interaction processes, eventually leading to a mineralization increase.
Nitrate contamination still remains one of the main groundwater quality issues in several aquifers worldwide, despite the perduring efforts of the international scientific community to effectively ...tackle this problem. The classical hydrogeological and isotopic investigations are obviously of paramount importance for the characterization of contaminant sources, but are clearly not sufficient for the correct and long-term protection of groundwater resources. This paper aims at demonstrating the effectiveness of the socio-hydrogeological approach as the best tool to tackle groundwater quality issues, while contributing bridging the gap between science and society. An integrated survey, including land use, hydrochemical (physicochemical parameters and major ions) and isotopic (δ15NNO3 and δ18ONO3) analyses, coupled to capacity building and participatory activities was carried out to correctly attribute the nitrate origin in groundwater from the Grombalia Basin (North Tunisia), a region where only synthetic fertilizers have been generally identified as the main source of such pollution. Results demonstrates that the basin is characterized by high nitrate concentrations, often exceeding the statutory limits for drinking water, in both the shallow and deep aquifers, whereas sources are associated to both agricultural and urban activities.
The public participation of local actors proved to be a fundamental element for the development of the hydrogeological investigation, as it permitted to obtain relevant information to support data interpretation, and eventually guaranteed the correct assessment of contaminant sources in the studied area. In addition, such activity, if adequately transferred to regulators, will ensure the effective adoption of management practices based on the research outcomes and tailored on the real needs of the local population, proving the added value to include it in any integrated investigation.
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•Effectiveness of socio-hydrogeology in groundwater quality assessment is proven.•Dual origin of nitrate contamination: fertilizers and anthropogenic organic matter.•High nitrates in the deep aquifer suggest hydraulic connections with the shallow.•Dissolution of evaporites is triggered by nitrate contamination.•Public participation provides essential information for correct data interpretation.
Fecal contamination of water is a worrying problem because it is associated with the transmission of enteric pathogenic microorganisms that can cause many infectious diseases. In this study, an ...environmental survey was conducted to assess the level of viral contamination by viable enterovirus and rotavirus genome in two recreational rivers (Suquía and Xanaes) of Córdoba, Argentina. Quantitative microbial risk assessment (QMRA) was calculated to estimate the risk of rotavirus infection. Water sampling was carried out during a one-year period, the presence of total and fecal coliforms was determined and water samples were then concentrated for viral determination. Cell culture and indirect immunofluorescence were applied for enterovirus detection and RT-qPCR for rotavirus quantification. Coliform bacteria levels found in Suquía River often far exceeded the guideline limits for recreational waters. The Xanaes exhibited a lower level of bacterial contamination, frequently within the guideline limits. Enterovirus and rotavirus were frequently detected in the monitoring rivers (percentage of positive samples in Suquía: 78.6% enterovirus, 100% rotavirus; in Xanaes: 87.5% enterovirus, 18.7% rotavirus). Rotavirus was detected at a media concentration of 5.7×105 genome copies/L (gc/L) in the Suquía and 8.5×100gc/L in the Xanaes. QMRA revealed high risk of rotavirus infection in the Suquía, at sampling points with acceptable and non-acceptable bacteria numbers. The Xanaes showed significantly lower health risk of rotavirus infection but it proved to be a public health hazard. The viral occurrence was not readily explained by the levels of bacteria indicators, thus viral monitoring should be included to determine microbiological water quality. These findings provide the first data of QMRA for recreational waters in Argentina and reveal the need for public awareness of the health implications of the use of the river waters.
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•Enteroviruses were frequently detected in both rivers of Córdoba.•Enteric viruses were identified in recreational waters with low bacterial loads.•QMRA revealed that recreational rivers represented a public health hazard.•Bacterial indicators do not reflect the risk from rotavirus infection.•Viral monitoring should be included to determine microbiological water quality.
In the last few years, the 28 nm CMOS technology has raised interest in the High Energy Physics community for the design and implementation of readout integrated circuits for high granularity ...position sensitive detectors. This work is focused on the characterization of the 28 nm CMOS node with a particular focus on the analog performance. Small signal characteristics and the behavior of the white and 1/f noise components are studied as a function of the device polarity, dimensions, and bias conditions to provide guidelines for minimum noise design of front-end electronics. Comparison with data extracted from previous CMOS generations are also presented to assess the performance of the technology node under evaluation.
In Argentina, the rotavirus disease exhibits seasonal variations, being most prevalent in the fall and winter months. To deepen the understanding of rotavirus seasonality in our community, the ...influence of meteorological factors on the rotavirus load and the genetic diversity in urban raw sewage from Córdoba city, Argentina were evaluated. Wastewater samples were collected monthly during a three-year study period and viral particles were concentrated by polyethylene glycol precipitation. RT-nested PCR was applied for rotavirus detection, and VP7/VP4 characterization and real-time PCR for rotavirus quantification. Both molecular techniques showed relatively similar sensitivity rates and revealed rotavirus presence in urban wastewater in cold and warm seasons, indicating its circulation in the local community all year round. However, a slight trend for rotavirus circulation was noted by real-time PCR in the fall and winter seasons, showing a significantly higher peak of rotavirus concentration at mean temperatures lower than 18°C and also higher, although not statistically different during drier weather. VP7 and VP4 gene characterization showed that G1 and P8 genotypes were dominant, and temporal variations in genotype distribution were not observed. Rotavirus spread is complex and our results point out that weather factors alone cannot explain the seasonal quantitative pattern of the rotavirus disease. Therefore, alternative transmission routes, changes in human behavior and susceptibility, and the stability and survivability of the virus might all together contribute to the seasonality of rotavirus. The results obtained here provide evidence regarding the dynamics of rotavirus circulation and maintenance in Argentina.
•Rotavirus circulates in the community all year-round.•A trend for rotavirus circulation is noted during the colder and drier seasons.•Significantly higher peaks of rotavirus concentration occur at mean temperatures lower than 18°C.•Temporal variations in genotype distribution were not observed.
The assessment of nitrate pollution origin using stable isotope techniques is a fundamental prerequisite for the application of sustainable groundwater management plans. Although nitrate pollution is ...a worldwide groundwater quality problem, existing knowledge on the origin of nitrate pollution in arid and semi-arid regions is still scarce. Using the example of the Grombalia aquifer (NE Tunisia), this work summarizes the main strengths and constraints of multi-isotope techniques targeting at nitrate source identification and apportionment The results highlighted that, even in the case of well-established methodologies, like those of isotope hydrogeochemistry (δ15NNO3, δ 18ONO3 and δ 11B) and mixing modelling for source apportionment, it is fundamental to take into account regional and local end-members to avoid biased data interpretation and to fully exploit the potential of such accurate tools.
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•Current knowledge of nitrate pollution origin in (semi)arid regions is still scarce.•New frontiers for nitrate source apportionment in (semi)arid regions are discussed.•δ15N/δ11B systematics: not effective for groundwater with high B natural background.•SIAR outcomes are highly dependent on the values attributed to the sources.•Unbiased source apportionment is fundamental to support groundwater management.
Despite being a vector of pollution towards connected ecosystems, groundwater is often underestimated or not taken into account in management frameworks. To fill this gap, we propose to add ...socio-economic data to hydrogeological investigations to identify past and present pollution sources linked to human activities at watershed scale in order to forecast threats towards groundwater-dependent ecosystems (GDEs). The aim of this paper is to demonstrate, by a cross-disciplinary approach, the added value of socio-hydrogeological investigations to tackle anthropogenic pollution fluxes towards a GDE and to contribute to more sustainable management of groundwater resources. A survey combining chemical compounds analysis, data compilation, land use analysis and field investigations with a questionnaire was carried out on the Biguglia lagoon plain (France). Results show a pollution with a two-fold source, both agricultural and domestic, in all water bodies of the plain. The pesticide analysis reveals the presence of 10 molecules, including domestic compounds, with concentrations exceeding European groundwater quality standards for individual pesticides, as well as pesticides already banned for twenty years. On the basis of both the field survey and the questionnaire, agricultural pollution has been identified as very local highlighting the storage capacity of the aquifer, whereas domestic pollution is diffuse over the plain and attributed to sewage network effluents and septic tanks. Domestic compounds present shorter residence time within the aquifer highlighting continuous inputs, related to consumption habits of the population. Under the Water Framework Directive (WFD), member states are required to preserve the good ecological status, quality and quantity of water bodies. However, for GDEs it is difficult to achieve the ‘good status’ required without considering the groundwater's pollutant storage capacity and pollution legacy. To help resolve this issue, socio-hydrogeology has proved to be an efficient tool as well as for implementing effective protection measures for Mediterranean GDEs.
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•Pollutant legacies accumulated pose a long term threat to GDEs.•Identification of domestic pollution from sewage water degrading waterbodies' quality•The socio-hydrogeological approach supported the identification of pollution sources.•Effectiveness of transdisciplinary approaches to understand hydrosystem's behavior•Implication of different actors necessary to improve Mediterranean GDEs management
Background. Stavudine is widely used in developing countries. Lipoatrophy and mitochondrial toxicity have been linked to stavudine use, but it is unclear whether switching to a lower dose can reduce ...these toxicities while maintaining human immunodeficiency virus (HIV) suppression. Methods. HIV-infected subjects receiving standard-dose stavudine with undetectable HIV type 1 RNA for ⩾6 months were randomized (ratio, 3:2) to receive one-half of the stavudine dose (switch arm) or to maintain the dose (continuation arm) while continuing to receive all other prescribed antiretrovirals. The following measurements were obtained at baseline and week 48: fasting lactate, pyruvate, and lipid levels; results of whole-body dual-energy x-ray absorptiometry; and mitochondrial DNA (mtDNA) measurements in fat and peripheral blood mononuclear cells. Change from baseline to week 48 was compared within and between groups. Results. Twenty-four patients (79% of whom were men and 79% of whom were African American; median age, 45 years) were enrolled in the study, 15 were enrolled in the switch arm, and 9 were enrolled in the continuation arm. The median duration of stavudine treatment was 55 months (range, 21–126 months). The median CD4 cell count was 558 cells/mm3 (range, 207–1698 cells/mm3). At baseline, the study arms had similar demographic characteristics and laboratory indices, except for body mass index, total lean body mass, and triglyceride levels (all of which were higher in the switch arm). Three patients (2 in the switch arm) discontinued the study because of study-unrelated reasons. CD4 cell counts remained unchanged. At 48 weeks, 6 patients (4 27% in the switch arm and 2 22% in the continuation arm) had detectable HIV RNA levels (median, 972 copies/mL; range, 60–49,400 copies/mL). All patients with detectable HIV RNA levels reported significant lapses in treatment adherence; none exhibited mutations in HIV genotype. After the treatment switch, significant changes from study entry to week 48 were noted only for lactate level (median change, −0.27 mmol/L; range, −1.2 to 0.25 mmol/L; P=.02) and fat mtDNA (median change, 40 copies/cell; range, −49 to 261 copies/cell; P=.02). In the continuation arm, a significant loss of bone mineral density was seen at week 48 (median change, −1.7%; range, −6.3% to 0.8%; P=.02). The only significant between-group difference was the change in bone mineral density from baseline (P=.003). Conclusions. Reducing stavudine dose by one-half increased fat mtDNA and decreased lactate levels, suggesting improvement in mitochondrial indices while preserving HIV suppression in subjects who maintained adherence. A significant loss of bone mineral density was seen in patients receiving standard-dose stavudine but not in those receiving low-dose stavudine. These results suggest that switching to low-dose stavudine may improve mitochondrial indices while maintaining virological suppression.
Summary
Given that low muscle mass can lead to worse health outcomes in patients with chronic infections, we assessed whether chronic hepatitis C virus (HCV) infection was associated with low muscle ...mass among US adults. We performed a cross‐sectional study of the National Health Examination and Nutrition Study (1999–2010). Chronic HCV‐infected patients had detectable HCV RNA. Low muscle mass was defined as <10th percentile for mid‐upper arm circumference (MUAC). Multivariable logistic regression was used to determine adjusted odds ratios (aORs) with 95% confidence intervals (CIs) of low muscle mass associated with chronic HCV. Among 18 513 adults, chronic HCV‐infected patients (n = 303) had a higher prevalence of low muscle mass than uninfected persons (13.8% vs 6.7%; aOR, 2.22; 95% CI, 1.39–3.56), and this association remained when analyses were repeated among persons without significant liver fibrosis (aOR, 2.12; 95% CI, 1.30–3.47). This study demonstrates that chronic HCV infection is associated with low muscle mass, as assessed by MUAC measurements, even in the absence of advanced liver disease.
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