Impaired Water Research Articles

Integration of renewable energy in wastewater treatment during COVID-19 pandemic: Challenges, opportunities, and progressive research trends

SARS-CoV-2 has aroused drastic effects on the global economy and public health. In response to this, personal protective equipment, hand hygiene, and social distancing have been considered the most important ways to prevent the direct spread of the virus. SARS-CoV-2 would be possible survive in wastewater for a few days, leading to secondary transmission via contact with water and wastewater. Thus, the most economical and practical approaches for decentralized wastewater treatment are renewable energies such as the solar energy disinfestation process. However, as freshwater requirements increase and fossil fuels become unsustainable, renewable energy becomes more attractive for desalination applications. Solar photovoltaic, membrane-based, and electricity desalination technologies are becoming increasingly popular due to their lower energy requirements. Several aquatic environments could be benefitted from solar energy wastewater disinfection. Besides, utilizing solar energy during the day can inactivate SARS-CoV-2 to nearly 90%. However, conventional membrane-based desalination practices have also been integrated, including reverse osmosis (RO) and electrodialysis (ED). Several exciting membrane processes have been developed recently, including membrane distillation (MD), pressure-reduced osmosis (PRO), and reverse electrodialysis (RED). Such operations can produce clean and sustainable electricity from brine and impaired water, generally considered hazardous to the environment. As a result, neither PRO nor RED can produce electricity without mixing a high salinity solution (such as seawater or brine and wastewater, respectively) with a low salinity solution. Herein, we critically review the progress in applying renewable energy such as solar energy and geothermal energy for generating electricity from wastewater treatment and uniquely discuss the effects of these two types of renewable energy on SARS-CoV-2 in air and wastewater treatment. We also highlight the significant process made on the membrane processes utilizing renewable energy and research gaps from the standpoint of producing clean and sustainable energy. The significant points of this review are: (1) among various types of renewable energy, solar energy and geothermal energy have been predominantly studied for wastewater treatment, (2) effects of these two types of renewable energy on SARS-CoV-2 in air and wastewater treatment are critically analyzed, and (3) the knowledge gaps and anticipated future research outlook have been consequently proposed thereof.

Disorder of the intestinal microbial tissue complex after a new coronavirus infection as an interdisciplinary problem

The occurrence of diarrhea in comorbid patients with COVID-19 infection against the background of microbiocenosis disorders may be a factor in the worse outcome of the disease. The biggest threat posed by diarrhea is dehydration. Evaluation, control and timely correction of disorders of the gastrointestinal tract, allowing to identify signs associated with dehydration, impaired water and electrolyte balance, intestinal microecology and phenomena of increased epithelial permeability. It is important to consider the risk of diarrhea in patients undergoing massive therapy for COVID-19. On the example of a specific clinical case, the most common mistakes in managing patients with acute/persistent diarrhea are analyzed. The tactics of managing a patient with diarrheal syndrome after a COVID-19 infection has been defined and substantiated, the importance of a holistic approach to solving patient problems from the standpoint of the one health concept has been substantiated.

A novel approach for produced water treatment: Supercritical water oxidation and desalination

Produced water generated from oil and gas operations contains significant quantities of environmentally hazardous hydrocarbons, organic chemicals, and inorganic salts. Environmental regulations with impaired water disposal mandates produced water treatment and desalination. Industry standard desalination technologies are energy-intensive and mandate extensive produced water pre-treatment including removal of hydrocarbons constituents for efficient operations. This study investigates a novel process intensification approach integrating supercritical water oxidation (SCWO) unit operation with a supercritical water desalination (SCWD) process for energy efficient produced water treatment and desalination. The coupled SCWD-SCWO process is found to be very energy-efficient and cost effective than existing industry standard desalination technologies. For energy efficient operation, the heat generated from the SCWO of hydrocarbons present in the produced water is used for power generation using a high efficiency and low-cost re-heat Rankine cycle process. The cost of treating produced water with proposed SCWO-SCWD process is independent of the salt concentration. The proposed process has the potential to offer step-change improvements over conventional processes in both the efficiency and cost of produced water treatment: for example, a cost and energy saving of 70% and 100% is calculated for the treatment of produced water containing 250 g/l salt and 10.6 g/l hydrocarbon.

Pattern Recognition versus Pathogenesis: Electrolytes in a Patient with Adrenal Insufficiency.

Pattern Recognition versus Pathogenesis: Electrolytes in a Patient with Adrenal Insufficiency.

Impacts of Surface Water Quality in the Awash River Basin, Ethiopia: A Systematic Review

Water quality impairment, due to anthropogenic activities and limited enforcement capacity, is a rapidly growing threat to water security as well as public health in developing countries. Cumulative effects of deteriorating water quality undoubtedly put pressure on public health and socio-economic developments. For example, most industries in Ethiopia discharge their effluent directly into freshwater systems without any treatment process. The problem is severe for rivers such as the Awash that pass through major cities. Although there were a few studies that looked into the issue, there is a lack of comprehensive water quality impact assessment on agriculture, health, and socio-economics. This article systematically summarizes current research on water quality issues in the Awash River Basin to generate comprehensive information that captures the water quality status of the river and impacts of water contamination, and identify information and management gaps. Results showed that water quality degradation along the river course and in selected tributaries exceeds water quality standards by the WHO and national guidelines. For example, E-coli bacteria concentration in two tributaries, Tinishu and Tiliku Akaki, reach up to 6.68 and 6.61 billion CFU 100 ml/L. Virological profile of creeks receiving wastewater from hospitals in the City of Addis Ababa contains coliphages levels reaching as high as 5.2 × 103 pfu/100 ml for urban rivers and up to 4.92 × 103 pfu/100 ml. Heavy metals that far exceed the tolerable levels for humans were also detected in vegetables produced using impaired water. Heavy metals such as Cd, Cr, Cu, Hg, Ni, and Zn were detected in potato, Zn and Hg in Cabbage, and Cr in onion and red beet. Lettuce irrigated with Akaki river water found to contain 0.263 (Cd), 420 (Fe), 13.44 (Zn), 7.87 (Cr), 7.49 (Cu), and 6.55 (Pb) in mg/kg both in excess of WHO guideline. In addition, a high concentration of Cr has been also found in fish tissues. There has never been a systematic evaluation of the impact of contaminated water in the Awash Basin. Comprehensive impact of water quality investigation that takes into account the different pollutants dynamic needs to be made to protect the well being of downstream beneficiaries including the aquatic ecosystem. In conclusion the systematic review has shown that for a river that cross-through emerging mega-city like Addis Ababa, the human and ecosystem health impact of aquatic ecosystems pollution should not afterthought action

Conservation practices induce tradeoffs in soil function: Observations from the northern Great Plains

AbstractOver the past 30 years, agricultural land use in the northern Great Plains has negatively affected soil health and associated ecosystem services through grassland conversion to cropland and a transition away from small‐grain cropping systems to warm‐season crops. Mitigating these effects requires adoption of conservation practices, but information about how conservation practices influence on soil condition and function are needed. This study sought to quantify near‐surface soil responses to crop diversity and intensity, cover crops, and livestock integration under controlled experimental conditions, and land use (dryland cropping vs. perennial agroecosystems) on working farms and ranches, all on a common Haplustoll soil in southcentral North Dakota, USA. Among dryland cropping practices, diverse, continuous cropping led to improvements in soil structure, nutrient supply potential, and biological habitat, but increased soil acidification and soil NO3–N accumulation. Cover crops had a negligible effect on soil condition and function, while livestock integration on cropland improved nutrient supply potential and biological habitat but impaired water intake into soil. Relative to dryland cropping, soil conditions and functions were consistently improved under perennial agroecosystems. Retention of perennial agroecosystems and adoption of diverse, nutrient‐efficient dryland cropping practices should be prioritized to enhance soil health in the northern Great Plains.

Cost-Benefit Analysis of Green Infrastructure for Sustainable Stormwater Management of the Built Environment

Green infrastructure is a modern network of decentralized stormwater management applications that can capture and infiltrate rain where it falls, thus diminishing stormwater runoff and improving the health of surrounding waterways. While there are unique scales of green infrastructure, such as large swaths of land set aside for preservation. Green infrastructure such as bioretention, green roofs, trees, and permeable pavement is important in today’s world since many municipalities are faced with the issues of aging gray infrastructure, impaired local water way, and projected population growth by 2030. Green stormwater infrastructure helps strengthen communities’ economy while providing environmentally and economically sustainable solutions to stormwater management issues. This study found that current stormwater runoff issues in municipalities across the United States will be substantially decreased with about 1.05 billion gallons diverted from sewer. This will yield about millions of dollars in annual savings and decrease buildings energy metered water use by 1.37 million kWh of carbon dioxide. Green infrastructure is needed to address and plan for the future impacts of climate change by preventing increased flood risks and public health stresses.

Disparities in drinking water compliance: Implications for incorporating equity into regulatory practices

AbstractDisparities in drinking water quality pose harm to public health across the United States. Yet, few studies have systematically analyzed disproportionate exposure to impaired drinking water. This study sheds light on disparities in health‐based drinking water violations and the shortcomings of regulatory assessment that only considers equity in terms of variation in compliance across system size. We examine the relationship between health‐based violations, utility size, and socioeconomic factors, using probit regression and a balanced panel dataset of 1693 community water systems in California from 2000 to 2018. Demographics of water systems are developed using areal weighting. We find evidence of water equity concerns. Violation rates are several times higher at systems serving low‐income areas and communities of color. These disparities are present even in models stratified by size of service population. Our findings highlight that equity in environmental regulation could be improved by considering factors beyond system scale.

Comparing normative and descriptive methods for multi-criteria decision analysis: A case study evaluating wetland restoration opportunities in the Chesapeake Bay watershed, USA

Normative and descriptive multi-criteria decision analysis methods were compared to understand their differences in providing decision insights, with a wetland restoration planning study, Chesapeake Bay watershed, USA. Excessive nutrient and sediment runoff is causing impaired water quality and degradation of aquatic habitat in the Chesapeake Bay. A team at The Nature Conservancy evaluated a decision to prioritize large-scale wetland restoration opportunities. A total of 964 potentially restorable wetland alternatives were delineated using spatial analysis. The alternatives were evaluated on seven water quality and climate resilience criteria. Normative methods included ranking the alternatives based on scaling and averaging criteria values per alternative using value and distance functions. Descriptive methods included grouping the alternatives based on their statistical similarities and dissimilarities using principal component analysis. Sensitivity analysis incorporated different data transformations based on risk and riskless decision contexts, different criteria weighting scenarios, and two formats for grouping alternatives. The descriptive method provided inherent information about tradeoffs that normative methods did not, whereas the normative methods provided a similar type of information about tradeoffs. Inherent tradeoff information can provide useful decision insights without complicated criteria scaling and weighting methods, which can be favorable to researchers that desire a more objective analysis. However, descriptive methods do not guarantee favorable results and should be considered along with preferences and judgments. Multiple methods can guide a more comprehensive approach to thinking about tradeoffs in other similar contexts. Data AvailabilitySupporting data are available on request: David.Martin@tnc.org.

Surface water quality analysis using multivariate statistical techniques: a case study of Fars Province rivers, Iran.

This study aimed to transform the input of a large dataset into the output of interpretable information. Hence, multivariate statistical methods were carried out to analyze physicochemical parameters in 34 rivers during a 17-year period (1997-2014). Cluster analysis divided the study area into spatially different riverine water quality sub-regions described in ascending order of water quality as severely polluted (SP), highly polluted (HP), polluted (P), moderately polluted (MP), lightly polluted (LP), and not polluted (NP). By diagnosing threats and identifying fragile zones, water contamination sources responsible for impaired water quality in the study area recognized as natural pollutants in LP, municipal wastes in P, discharge of industrial effluents in MP, natural geochemical formations in SP and HP, and superficial flows of agricultural lands in SP, HP, and MP. The dominant water type in each zone wasclassified into Na-Cl, Na-Cl, Na-Mg-Ca-Cl-SO4, Na-Ca-Mg-Cl-SO4, Na-Ca-Cl, and Ca-Mg-HCO3-SO4 groups for SP, HP, P, MP, LP, and NP, respectively. To explore aesthetic aspects of drinking water application, hazard quotient (HQ) was applied for children and adults in terms of ingestion and dermal exposure. Overall health risk assessment revealed the order of impacts of the secondary water quality parameters as Cl- > Na+ > total dissolved solids (TDS) > Ca2+ > SO42- > Mg2+. Furthermore, hazard index (HI) ranged from 0.011 to 31.439 and 0.010 to 30.122 for children and adults, respectively, indicating a potential health risk regarding chloride throughout the whole region excluding NP. To identify significant agents in water quality, principal component analysis extracted 3 varifactors (VFs), with the eigenvalues of 4.74, 1.19, and 0.85, respectively, explained about 83% of the variance. The most important parameters in the first factor were TDS, electrical conductivity, SAR, TH, Na+, Cl-, and SO42- accounting for 58% of the total variance. The most influenced parameters in the second and third factors were pH and HCO3-, respectively, with variance coverage of 26%. These factors indicated that the hydrochemical characteristics of the water originated by natural interactions (existing salt domes, evaporation, weathering, and soil erosion) and anthropogenic activities (fertilizer-rich flows of agro-fields and domestic/industrial disposals), which must be minimized in rivers to supply the population with hygienic water.

Microbiome of Bacterially Impaired Watersheds: Distribution of Potential Bacterial Pathogens

Bacterial impairment of freshwater systems is a commonly studied global problem. However, studies on the relative distribution of bacterial pathogens in different impaired aquatic systems have been limited. Frequently, impaired freshwater systems are classified by the presence of fecal indicator bacteria (FIB) and the identification of sources of fecal contamination through microbial source tracking. In this study, we assessed the relative abundance of DNA sequences related to potential human bacterial pathogens along with human fecal indicator bacteria in three impaired watersheds. These watersheds consistently showed a high abundance of FIB for the past several years. Using Illumina paired-end DNA sequencing of 16S rRNA gene amplicons, we observed variation in the relative distribution of DNA sequences related to Legionellaceae, Enterobacteriaceae and Bacteroidaceae families across different sites. We identified potential hotspots sites in these impaired water systems, which showed a relatively high abundance of pathogen-related DNA sequences. This study demonstrates the significance of Next-Gen DNA sequencing for the initial screening of waterborne pathogens and the identification of high-risk sites for preferential remediation efforts in impaired water systems. Secondly, the frequent temporal monitoring of specifically identified pathogens that are in high abundance in a watershed can help in the accurate prediction and prevention of disease outbreaks.

Oryeongsan (Wulingsan) ameliorates impaired ANP secretion of atria from spontaneously hypertensive rats

Oryeongsan (ORS), a herbal medicine formula, has long been used for the treatment of impaired body water balance in Asian countries. Recently, it was shown that ORS administration modulates the renin-angiotensin system (RAS). Purpose of the present study was to determine characteristics of atrial ANP secretion and effects of ORS on the secretion in the atria from spontaneously hypertensive rats (SHR). Normotensive WKY groups (WKY-V, WKY-ORS, WKY-LOS) and hypertensive SHR groups (SHR-V, SHR-ORS, SHR-LOS) treated with vehicle, ORS, and losartan as a positive control group, respectively, were used. Experiments were performed in perfused beating atria (1.3 Hz) allowing atrial distension, acetylcholine (ACh) stimulation, and serial collection of atrial perfusates. The secreted ANP concentration was measured using radioimmunoassay. Interstitial fluid (ISF) translocation was measured using [3H]inulin clearance. Stepwise increase in atrial distension by 1.1, 2.0, and 2.7 cmH2O above basal distension further increased ANP secretion proportionally in the atria from WKY-V, but the response was significantly suppressed in the atria from SHR-V. Cardiomyocyte ANP release, the first step of atrial ANP secretion, was suppressed in the atria from SHR-V compared to those from WKY-V (−8.02 ± 2.86, −15.86 ± 2.27, and −20.09 ± 3.62%; n = 8, for SHR-V vs. 8.59 ± 2.81, 15.65 ± 7.14, and 38.12 ± 8.28%; n = 8, for WKY-V; p < 0.001 for all stepwise distension, respectively). Chronic treatment with ORS reversed the suppressed ANP release in atria from SHR-ORS group (6.76 ± 3.92, 9.12 ± 2.85, and 28.79 ± 1.79% for SHR-ORS; n = 5 vs. SHR-V; n = 8; p = 0.01, p < 0.001, p < 0.001, respectively). The effects of ORS were comparable to those of losartan. Trans-endocardial translocation of ISF, the second step of atrial ANP secretion was similar in the atria from the hypertensive SHR-V and normotensive WKY-V. ACh-induced ANP secretion and cardiomyocyte ANP release were also suppressed in the atria from SHR-V compared to WKY-V and ORS reversed the suppression. These findings were accompanied with accentuation of the AT1 receptor expression and suppression of the AT2/Mas receptor, M2 mACh receptor and GIRK4, a molecular component of KACh channel, expression in the atria from SHR-V. Further, treatment with ORS or losartan reversed the expressions in the groups of SHR-ORS and SHR-LOS. These results show that ANP secretion is suppressed in the atria from SHR in association with accentuation of AT1 receptor and suppression of AT2/Mas receptor and KACh channel expression. Treatment with ORS ameliorates impaired ANP secretion through improving cardiomyocyte ANP release with modulation of the cardiac RAS and muscarinic signaling. These findings provide experimental evidence which supports the effect of ORS on the regulation of atrial ANP secretion in the atria from SHR.

Taquacetuba Compartment of Billings Reservoir (SP, Brazil): differential influence of the main water body and tributaries in the water quality

Abstract Aim This research evaluated the water quality of the Taquacetuba Compartment, Billings Reservoir (Brazil), through analyzes of water quality data. The Taquacetuba Compartment has multiple uses such as public water supply and professional fishing activity and is of fundamental importance for the population of São Paulo State. Methods Sampling were conducted at the Compartment entrance (P1), close to the collecting point for public water supply transposition (P2), and in the mouths of the main tributaries (P3 - P6) forming the Compartment. Samplings were concentrated in the wet and dry periods of 2017. The physical and chemical variables measured were temperature, dissolved oxygen, pH, electrical conductivity, turbidity, chlorophyll α, ammonia nitrogen, nitrite, nitrate, total nitrogen, orthophosphate and total phosphorus. Results The Taquacetuba Compartment exhibited impaired water quality evidenced by high electrical conductivity, chlorophyll α and total phosphorus, above the legislation limits, classifying the sampling point as super or hyper eutrophic condition. The P1 sampling point presented the greatest environmental stress with worse water quality during the rainy season, while the other points (P2 - P6) showed an improvement during rainfalls. The P5 and P6, located at the tributaries mouth of the Monos and Curucutu River respectively, presented the best environmental conditions, evidenced by tendency to higher oxygen levels and lower turbidity in the rainy period. Conclusions From the observed result, we recognized two principal sources responsible for the impairment of the water quality in the Taquacetuba Compartment: i) the contribution from the central body of Billing Reservoir, related to the greater negative influence of the water pumping from the Pinheiros River with great organic load, especially in the wet period, and ii) the contribution from the tributaries, being that the Monos and Curucutu tributaries, as they are in an indigenous reserve area have better water quality. This study recognize the importance of land use and soil occupation around the tributaries and contribute with original data to support management measures for improving water quality in the Taquacetuba Compartment.

Synthesis and validation of polystyrene-based polyethylenimine composite for Cr(VI) removal from aqueous solution: Performance and mechanism

With increasing groundwater and surface water contamination due to improper discharge of chromium-laden wastewaters, it is compelling to synthesize a material that can selectively remove Cr(VI) from the impaired water at neutral or near-neutral pH. In this study, various composites were synthesized through chemical grafting of polyethylenimine (PEI) polymer on the surface of INDION PA 800 polystyrene beads by varying the PEI loading and glutaraldehyde (GA) crosslinking for Cr(VI) removal. The adsorbent called PS-7 with 16% PEI and 2.5% GA crosslinking performed best, demonstrating Cr(VI) removal greater than 99% even at pH 9. The adsorbent showed significant trace Cr(VI) removal from the impaired solution containing competing anions at 500 times the concentration of Cr(VI) at neutral pH. Further, 1.0 g/L adsorbent showed 100% Cr(VI) removal from a solution containing 5 mg/L Cr(VI) at pH 7 and 9. PS-7 showed significant adsorption capacity of 355.26 and 143.6 mg/g for fixed-bed column runs at influent pH 3 and 5, respectively. An insightful investigation revealed that the use of hydrophobic matrix for PEI immobilization played an important role in Cr(VI) removal at neutral pH, as opposed to the other reported PEI-based adsorbents with hydrophilic matrix which were capable of removing chromate anions at acidic pH only. The phenomenon of redox reaction occurring in the adsorbent was validated by X-ray photoelectron spectroscopy, where Cr(VI) was reduced to Cr(III) with the help of electron-donating NH2 groups and the adsorbent got oxidized. Thus, PS-7 adsorbent holds immense potential for treating real-life Cr(VI)-contaminated waters.

Environmental and Socio-Economic Impacts of Kariba Weed Infestation of Lakes Kyoga and Kwania, Uganda

The objective of this study was to quantify the coverage of Kariba weed (Salvinia molesta) on lakes Kyoga and Kwania and document the environmental and socio-economic impacts associated with its infestation. Data on weed infestation status was collected in 2017 and compared with pre-infestation period of 2013. Weed infestations were approximately 15,643 and 13,688 ha on lakes Kyoga and Kwania respectively. The infestation impaired fishing activities, water quality, water abstraction and water transport. They also led to 20.4, 60.1, 7.7, 17.6 and 5.7 kg reduction in catches per day for Tilapia, Mukene, Catfish, Nile perch and Mudfish respectively. The infestations were also associated with a general increase in the prices of the fish. Individual fishermen registered losses in fish revenue. Household spent approximately UGX 108,523 annually as treatment costs for diseases associated with weed infestation. While 32% of the respondents tried to manually control the waterweed at approximately UGX 83,988/year, the mobile nature of the weed rendered these efforts unsuccessful. A strategy to sustainably control the waterweed using specific bio-control agents (Cyrtobagous salviniae) is recommended.

Arbuscular mycorrhizae alleviate water deficit in Dipteryx alata Vogel: seedling quality and resilience

Dipteryx alata Vogel (Fabaceae) is a fruit tree species native to the Cerrado with ecological and economic potential. However, a water deficit can be a limiting factor to the initial growth of this species, requiring knowledge on technologies that can alleviate this stressful effect. We hypothesized that inoculation with arbuscular mycorrhizae fungi contributes to stress mitigation during and after water deficit. Dipteryx alata seedlings were subjected to two water regimes (control: seedlings irrigated daily; and water deficit: irrigation suspension), associated with inoculation with arbuscular mycorrhizal fungi (AMF) (AM–, without inoculation; AM+, inoculation with Rhizophagus clarum), and three evaluation periods (T0, time zero; F0, zero photosynthesis (7 days of water restriction); REC, recovery (100 days)). Water deficit impaired water relations, decreasing the quality of D. alata seedlings. AM+ seedlings showed higher relative water content (RWC), leaf area ratio, chlorophyll index, and Rubisco carboxylation capacity (A/Ci), which helped in photosynthetic metabolism. Inoculation with R. clarum alleviated the impact of stress on water use efficiency, water potential, RWC, and A/Ci in REC. Inoculation with AMF is a promising management technique in the production of D. alata seedlings for increasing seedling quality and resilience to water deficit.

Evaluation of Methionine Sources in Protein Reduced Diets for Turkeys in the Late Finishing Period Regarding Performance, Footpad Health and Liver Health

Footpad dermatitis and hepatic lipidosis are health problems in fattening turkeys where a positive influence of higher methionine content in feed is discussed. The effects of the methionine supplements DL-methionine (DLM) and liquid methionine hydroxyl analogue free acid (MHA-FA) under the aspect of low protein diets were investigated in this study based on performance parameters, footpad health, liver health and oxidative stress. In this study, 80 female turkeys (B.U.T. Big 6) of 63 day-old, were randomly assigned to four groups characterising a 2 × 2 factorial design with five replicates each over five weeks. The groups were fed with diets differing in methionine source (DLM vs. MHA-FA, assuming a biological activity of MHA-FA of 65%) and crude protein content (15% vs. 18%) for 35 days. The results showed no significant interactions between the protein content and methionine source. Strong protein reduction significantly impaired water intake, feed intake, weight gain and feed conversation ratio, but improved footpad health. DLM and MHA-FA addition had no significant effect on weight gain, crude fat and protein contents in the liver, but DLM resulted in a significant increase in livers antioxidative capacity compared to MHA-FA. Although the protein reduction resulted in reduced performance, the study showed that MHA-FA can be replaced by DLM in a 100:65 weight ratio without compromising performance but with certain advantages in the antioxidative capacity of the liver.

Improved salinity tolerance in early growth stage of maize through salicylic acid foliar application

Soil salinity threatens agricultural production worldwide by constraining plant growth and final crop yield. The early stages are most sensitive to salinity, in response to which salicylic acid (SA) has demonstrated beneficial effects in various plant species. Based on this, a maize (Zea mays L.) pot experiment was set up combining three levels of soil salinity (0, 6 and 12 dS m–1), obtained through NaCl addition, with three levels of SA (0, 300 and 600 mM), applied by leaf spraying 20 days after seedling emergence. Fifteen days later, the following traits were assessed: morphology (plant height, leaf number), growth (root and shoot dry weight), leaf water status [relative water content (RWC), electrolyte leakage (EL)], pigments (chlorophyll a and b, carotenoids, anthocyanin), antioxidant enzymes (peroxidase, catalase, ascorbate peroxidase, vitamin C), oxidative stress markers (H2O2, malondialdehyde), osmo-regulating compounds (free amino acids, soluble proteins and sugars, proline), hormones [indole-3-acetic acid, gibberellic acid (GA), abscisic acid (ABA), ethylene], element (Na, K, Ca, Mg and Cl) concentration and content in roots, stem and leaves. Salinity severely affected maize growth (–26% total dry weight), impaired leaf water status (–31% RWC), reduced photosynthetic pigments, enhanced all antioxidant enzymes and oxidative stress markers, two osmo-regulating compounds (soluble sugars and proline) out of four, and all hormones except GA. SA was shown effective in containing most of the stress effects, while supporting plant defences by upgrading antioxidant activities (reduced oxidative stress markers), increasing cell membrane stability (–24% EL) and leaf water status (+20% RWC), and reducing plant stress signalling (–10% ABA and -20% ethylene). Above all, SA contrasted the massive entry of noxious ions (Na+ and Cl–), in favour of K+, Ca2+ and Mg2+ accumulation. Lastly, salicylic acid was shown beneficial for maize growth and physiology also under non-saline condition, suggesting a potential use in normal field conditions. Highlights - Foliar applied salicylic acid alleviated salinity effects on maize growth at early plant stage. - Salicylic acid improved leaf water status, chlorophyll content, and strengthened anti-oxidant enzymes under salinity. - Salicylic acid reduced oxidative stress markers while enhancing osmo-regulating and hormonal responses to salinity. - Salicylic acid hampered Na and Cl entry and translocation to above ground organs, preserving leaf cell membrane integrity. - Salicylic acid was shown beneficial for maize growth and physiology also under non-saline conditions.

Long‐Term Disconnect Between Nutrient Inputs and Riverine Exports in a Semi‐Arid, Agricultural Watershed: Yakima River Basin 1945–2012

AbstractNutrient budgets are useful tools in addressing impaired water quality from increasing anthropogenic nitrogen (N) and phosphorus (P) inputs to watersheds. Long term analyses can identify temporal ecological responses to past nutrient management strategies. Multidecadal watershed analyses of nutrient dynamics traditionally have been limited to large humid or mesic river basins focused primarily on a single nutrient (N or P). Here we present a long term, dual N and P input‐output budget for the agriculturally rich Yakima River Basin (YRB) located in the semi‐arid western U.S. We quantified N and P terrestrial inputs from 1945 to 2012 using past agricultural and water quality data to investigate interactions between water flow and N and P exports in the YRB. Between 1945 and 2012, N and P inputs to agricultural lands increased by over 18 and 10‐fold, respectively, with synthetic fertilizer accounting for the majority of input increases. While such increases in nutrient inputs were comparable to other U.S. basins, observed riverine N and P export did not significantly increase over time. Rather, we found that since the mid‐1970s both N and P loads and concentrations in the Yakima River have decreased, indicating a temporal disconnect between nutrient inputs and riverine exports in the YRB. This disconnect highlights a need to further investigate nutrient dynamics at local scales in semi‐arid watersheds. Our analysis raises questions about long‐term N and P retention in the YRB and potential impacts on future water quality across the western US.

The Effect of Class C Fly Ash on the Water Impermeability of Brick Body

The effect of fluidized fly ash (Tisová, ČEZ Group Czech Republic, class C according to ASTM C618) on the porosity (water absorption, bulk density, capillarity) and water impermeability of brick body used for the production of clay roofing tiles (Wienerberger, Czech Republic). The properties of plastic body (mixing water, drying shrinkage) are discussed too. The addition (10 %wt) of fluidized fly ash in the raw materials mixture for the production of clay roofing tiles generally reduces the sensitivity to the formation of reducing cores during firing thanks to higher porosity of dried green body (higher mixing water) - this is also related to the higher water absorption and capillarity of the fired body and hence to the impaired water impermeability when the fly ash is used.