A5001386770- Groundwater and Isotope Geochemistry
- Groundwater flow and contamination studies
- Hydrology and Watershed Management Studies
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Soil and Water Nutrient Dynamics
- Water Quality and Resources Studies
- Radioactive contamination and transfer
- Atmospheric and Environmental Gas Dynamics
- Coastal wetland ecosystem dynamics
- Geology and Paleoclimatology Research
- Particle Accelerators and Free-Electron Lasers
- Peatlands and Wetlands Ecology
- Methane Hydrates and Related Phenomena
- Electric Motor Design and Analysis
- Cryospheric studies and observations
- Archaeology and Natural History
- Water Treatment and Disinfection
- Plant Water Relations and Carbon Dynamics
- Marine and coastal ecosystems
- Tropical and Extratropical Cyclones Research
- Coastal and Marine Dynamics
- Reservoir Engineering and Simulation Methods
- Flood Risk Assessment and Management
- Soil erosion and sediment transport
Lawrence Livermore National Laboratory
2016-2025
California State University, East Bay
2012
Deltares
2009-2011
Utrecht University
2004-2009
Netherlands Organisation for Applied Scientific Research
2005
Fermi National Accelerator Laboratory
1973-1995
KWR Water Research Institute
1980-1982
Argonne National Laboratory
1965-1967
This paper describes a method for determining the potential of water supporting microbial regrowth in drinking distribution system. The is based on growth fluorescent pseudomonads as function concentration easily assimilable organic carbon (AOC) water. Using this method, authors analyzed samples from various stages treatment and which nonmetallic piping materials had been placed. AOC increased if was ozonated or placed contact with plasticized polyvinyl‐chloride.
Abstract One of the principal questions in hydrology is how and when water leaves critical zone storage as either stream flow or evapotranspiration. We investigated subsurface selection Southern Sierra Critical Zone Observatory (California, USA) within age‐ranked framework, constrained by a novel combination cosmogenic radioactive stable isotopes: tritium, sodium‐22, sulfur‐35, oxygen‐18. found significant positive correlation between tritium rate sulfur‐35 rate, indicating that age...
Abstract Groundwater ages provides insight into recharge rates, flow velocities, and vulnerability to contaminants. The ability predict groundwater based on more accessible parameters via Machine Learning (ML) would advance our guide sustainable management of resources. In this study, ML models were trained tested a large data set tritium concentrations tritium‐helium from the California Central Valley, basin with complex land use, irrigation, water practices. 63 features, including...
Groundwater age is a key aspect of production well vulnerability. Public drinking water supply wells typically have long screens and are expected to produce mixture groundwater ages. The distributions seven the Holten field (Netherlands) were estimated from tritium‐helium ( 3 H/ He), krypton‐85 85 Kr), argon‐39 39 Ar), using new application discrete distribution model existing mathematical models, by minimizing uncertainty‐weighted squared differences modeled measured tracer concentrations....
The Facility for Rare Isotope Beams (FRIB) at Michigan State University provides a unique opportunity to access some of the nation's most specialized scientific resources: radioisotopes. An excess useful radioisotopes will be formed as FRIB fulfills its basic science mission providing rare isotope beams. In order beams reach high-purity, many isotopes are discarded and go unused. If harvested, unused could enable cutting-edge research diverse applications ranging from medical therapy...
Nitrate is one of the most abundant contaminants in groundwater globally, United States, and California (CA). We studied well construction information, water chemistry, stable isotopes, noble gases to understand how travel time recharge source mechanism control nitrate concentrations domestic wells San Joaquin Valley (SJV), CA, a large semiarid, irrigated agricultural region. Using nonparametric statistics, we find decreasing trend nitrates with depth. Samples collected from that are closer...
Abstract Salt marshes exist at the terrestrial-marine interface, providing important ecosystem services such as nutrient cycling and carbon sequestration. Tidal inputs play a dominant role in salt marsh porewater mixing, terrestrially derived freshwater are increasingly recognized sources of water solutes to intertidal wetlands. However, there remains critical gap understanding on hydrology, how this may impact subsurface salinity plant productivity. Here, we address knowledge by examining...
The ability of an Aeromonas hydrophila isolate obtained from filtered river water to grow at low substrate concentrations was studied in batch experiments with tap supplied substrates. Growth assessed by colony count determinations. only multiplied the used (2 3 mg dissolved organic carbon per liter) after addition a small amount assimilable compound. d -Glucose especially caused growth organism even initial below 10 μg C liter. At glucose K s value (12 liter), generation times and yield...
The production of gases in groundwater under contaminated locations by geochemical and biological processes is not uncommon. Degassing these from repartitioning noble between water gas phase distorts dating 3 H/ He. We observed concentrations below atmospheric equilibrium 20 out 34 samples agriculturally polluted sandy areas the Netherlands. From absence nitrate degassed samples, we conclude that denitrification causes degassing. 22 Ne/ Ne ratios show degassing had attained solubility caused...
Gas exchange across the air-water interface is a critical process that maintains adequate dissolved oxygen (DO) in water column to support life. Oxygen reaeration rates can be accurately measured using deliberate gas tracers, like sulfur hexafluoride (SF6) or xenon (Xe). Two continuous release experiments were conducted different creeks Sierra Nevada of California: Sagehen Creek September, 2009, SF6 and Martis August, 2012, both Xe. Measuring loss along creek, which was approximated with...
Abstract. High nitrogen (N) and phosphorus (P) fluxes from upstream agriculture threaten aquatic ecosystems in surface waters estuaries, especially areas characterized by high agricultural N P inputs densely drained catchments like the Netherlands. Controlled drainage has been recognized as an effective option to optimize soil moisture conditions for reduce unnecessary losses of fresh water nutrients. This is achieved introducing control structures with adjustable overflow levels into...
Abstract Groundwater is not a sustainable resource, unless abstraction balanced by recharge. Identifying the sources of recharge in groundwater basin critical for management. We studied importance river water to south‐eastern San Joaquin Valley (24,000 km 2 , population 4 million). combined dissolved noble gas concentrations, stable isotopes, tritium, and carbon‐14 analyses analyse sources, mechanisms, timescales Area‐representative sampling numerical model input data enabled isotope mass...
A new method is described for measuring dissolved gas concentrations in small volumes of xylem sap using membrane inlet mass spectrometry. The technique can be used to determine atmospheric gases, such as argon, reported here, or any gases and their isotopes a variety applications, rapid detection trace from groundwater only hours after they were taken up by trees rooting depth estimation. Atmospheric content directly affects the conditions mechanisms that allow removal embolisms, because...
Large detectors employing xenon are a leading technology in existing and planned searches for new physics, including neutrinoless double beta decay ($0\nu\beta\beta$) dark matter. While upcoming will employ target masses of ton or more, further extending gas liquid phase Xe to the kton scale would enable extremely sensitive next-generation rare phenomena. The key challenge this well beyond is acquisition itself. We describe motivation time projection chambers (TPCs) possible avenues that...
Land use changes and the intensification of agriculture since 1950s have resulted in a deterioration groundwater quality many European countries. For protection quality, it is necessary to (1) assess current status, (2) detect or trends (3) threat (4) predict future quality. A variety approaches tools can be used extrapolate ranging from simple linear statistics distributed 3D contaminant transport models. In this paper we report on comparison four methods for detection extrapolation...
Abstract The atmospheric abundance of 81 Kr is a global integrator cosmic rays. It insensitive to climate shifts, geographical variations, and short‐term solar cycle activity, making it an ideal standard test models cosmic‐ray flux on the time scale 10 5 years. Here we present first calculation absolute production rates in atmosphere, measurement Kr/Kr via Atom Trap Trace Analysis method. result significantly deviates from previously reported values. agreement between model prediction...