Anthropogenic increase in atmospheric nitrogen (N) deposition in nature areas results in nitrate leaching to groundwater, threatening its quality. Member states of the European Union are obliged to reduce groundwater nitrate concentrations and to monitor this reduction. The relationship between N deposition and groundwater nitrate concentrations is quantified using a field survey and geographical information. Nitrate concentrations of the uppermost metre of groundwater in nature areas in the sandy regions in 1990 were related to geographical data by means of regression analysis. In this way nitrate concentrations could be explained by potential ammonia deposition, soil type, vegetation and land use. We found that about 35% of 54 kg ha(-1) a(-1) atmospheric N deposition was leached to the upper groundwater as nitrate, resulting in a mean NO3 concentration of about 30 mg L(-1). The critical N load for exceeding the EC limit value (50 mg L(-1)) in the sandy regions of The Netherlands composed of natural vegetation will be about 80 kg ha(-1) a(-1). Leaching is less than expected for nature areas but comparable with leaching of N surpluses in pastures in The Netherlands. A reduction in nitrate leaching by 25% or more can currently be detected via a new field survey.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1023/b:emas.0000016788.24386.be | DOI Listing |
iScience
January 2025
Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
The electroreduction of nitrate has emerged as a promising global strategy for water purification in the face of harmful nitrate in wastewater. However, the usually low concentration of nitrate in wastewater poses a great challenge to this process, thus necessitating more in-depth studies to optimize its efficiency. This perspective article briefly explores the various electrochemical pathways of nitrate reduction, including the conversion of nitrate to ammonia, the conversion of nitrate to dinitrogen, and the C-N coupled reduction process.
View Article and Find Full Text PDFPNAS Nexus
January 2025
Faculty of Health and Life Sciences, University of Exeter Medical School, University of Exeter, St Luke's campus, Exeter EX1 2LU, United Kingdom.
Apolipoprotein () genotype and nitric oxide (NO) deficiency are risk factors for age-associated cognitive decline. The oral microbiome plays a critical role in maintaining NO bioavailability during aging. The aim of this study was to assess interactions between the oral microbiome, NO biomarkers, and cognitive function in 60 participants with mild cognitive impairment (MCI) and 60 healthy controls using weighted gene co-occurrence network analysis and to compare the oral microbiomes between carriers and noncarriers in a subgroup of 35 MCI participants.
View Article and Find Full Text PDFPaediatr Perinat Epidemiol
January 2025
Department of Epidemiology, Boston University School of Public Health, Boston, Massachusetts, USA.
Background: Epidemiologic studies have demonstrated that ambient concentrations of particulate matter < 2.5 μm (PM) are associated with reduced fecundability, the per cycle probability of conception. The specific constituents driving this association are unknown.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, USA.
Discharge of wastewater containing nitrate (NO) disrupts aquatic ecosystems even at low concentrations. However, selective and rapid reduction of NO at low concentration to dinitrogen (N) is technically challenging. Here, we present an electrified membrane (EM) loaded with Sn pair-atom catalysts for highly efficient NO reduction to N in a single-pass electrofiltration.
View Article and Find Full Text PDFMar Environ Res
January 2025
Channel Islands National Marine Sanctuary, United States.
The Southern California Bight is an ecologically important region for many local and migratory fauna. We combine bulk and compound-specific amino acid stable isotope measurements in the skeletons of proteinaceous octocorals with new regional ocean modeling system model output to explore biogeochemical changes at two locations within the Bight - Santa Cruz Basin and Santa Barbara Channel. Separated by the Channel Islands, these sites display distinct oceanographic regimes.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!