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Cyanotoxins are a group of organic compounds biosynthesized intracellularly by many species of cyanobacteria found in surface water. The United States Environmental Protection Agency has listed cyanotoxins on the Safe Drinking Water Act's Contaminant Candidate List 3 for consideration for future regulation to protect public health. Cyanotoxins also pose a...

This report is a release of digital data from a helicopter electromagnetic and magnetic survey conducted by Fugro Airborne Surveys in areas of eastern Nebraska as part of a joint hydrologic study by the Lower Platte North and Lower Platte South Natural Resources Districts, and the U.S. Geological Survey. The...

The Energy Independence and Security Act of 2007 (EISA) requires the U.S. Department of the Interior (DOI) to develop a methodology and conduct an assessment of carbon storage, carbon sequestration, and greenhouse-gas (GHG) fluxes in the Nation's ecosystems. The U.S. Geological Survey (USGS) has developed and published the methodology (U.S....

Scientists and geographers have provided multiple datasets and maps to document temporal changes in vegetation types and land-water relationships in coastal Louisiana. Although these maps provide useful historical information, technological limitations prevented these and other mapping efforts from providing sufficiently detailed calculations of areal changes and shifts in habitat coverage....

Interactions between hydrothermal fluids and rock alter mineralogy, leading to the formation of secondary minerals and potentially significant physical and chemical property changes. Reactive transport simulations are essential for evaluating the coupled processes controlling the geochemical, thermal and hydrological evolution of geothermal systems. The objective of this preliminary investigation is...

Lake Maumelle is one of two principal drinking-water supplies for the Little Rock and North Little Rock metropolitan areas. Lake Maumelle and the Maumelle River (its primary tributary) are more pristine than most other reservoirs and streams in the region. However, as the Lake Maumelle watershed becomes increasingly more urbanized...

Reductive biostimulation is currently being explored as a possible remediation strategy for U-contaminated groundwater, and is being investigated at a field site in Rifle, CO, USA. The long-term stability of the resulting U(IV) phases is a key component of the overall performance of the...

Wastewater treatment plants are often the most substantial contributor of trace organic compounds including pharmaceuticals, steroidal hormones, and surfactants to surface waters. Studying stream reaches below wastewater treatment plants provide valuable information on the environmental persistence of these compounds. Three methods for conducting field...

This review summarises and evaluates the present knowledge on the behaviour, the biological effects and the routes of uptake of silver nanoparticles (Ag NPs) to organisms, with considerations on the nanoparticle physicochemistry in the ecotoxicity testing systems used. Different types of Ag NP syntheses, characterisation techniques and predicted current and future concentrations in the environment...

The fate of hydrocarbons in the subsurface near Bemidji, Minnesota, has been investigated by a multidisciplinary group of scientists for over a quarter century. Research at Bemidji has involved extensive investigations of multiphase flow and transport, volatilization, dissolution, geochemical interactions, microbial populations, and biodegradation with the...

No abstract available....

Blue oak tree-ring chronologies correlate highly with winter–spring precipitation totals over California, with Sacramento and San Joaquin river stream flow, and with seasonal variations in the salinity gradient in San Francisco Bay. The convergence of fresh and saline currents can influence...

Increasing salinity loading in the Colorado River has become a major concern for agricultural and municipal water supplies. The Colorado Salinity Control Act was implemented in 1974 to protect and enhance the quality of water in the Colorado River Basin. The U.S. Geological Survey, in cooperation with the Bureau of...

The project was initiated in April 2010, and to date has included four sampling events of surface water (April, May, June/July, and August 2010) and five sampling events of biota (April, May, June/July, August, and September 2010) and three sampling events for surface...

No abstract available....

The concept of a nonreactive or conservative tracer, commonly invoked in investigations of solute transport, requires additional study in the context of electrical geophysical monitoring. Tracers that are commonly considered conservative may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system. As a result,...

Two hydrologic models, MODFLOW with the Farm Process (MF-FMP) and the Integrated Water Flow Model (IWFM), are compared with respect to each model’s capabilities of simulating land-use hydrologic processes, surface-water routing, and groundwater flow. Of major concern among the land-use processes was the consumption of water through evaporation and transpiration...

More than half of the original Everglades extent formed a patterned peat mosaic of elevated ridges, lower and more open sloughs, and tree islands aligned parallel to the dominant flow direction. This ecologically important landscape structure remained in a dynamic equilibrium for millennia prior to rapid degradation over the past...

The concentration and form of dissolved organic C (DOC) and N species (NH4+ and NO3-) were investigated as part of a larger hydrogeochemical study of the Cottonwood Lake Study Area within the Prairie Potholes region. Groundwater, pore water and surface wetland water data were used to help characterize the relationships...

The potential effects of long-term urbanization and climate change on the freshwater resources of the Flint River basin were examined by using the Precipitation-Runoff Modeling System (PRMS). PRMS is a deterministic, distributed-parameter watershed model developed to evaluate the effects of various combinations of precipitation, temperature, and land cover on streamflow...

Streams and their surrounding catchments exchange water and solutes on a range of physical scales. Exchange with the stream may extend into the interstitial areas of the streambed, the hyporheic zone, the riparian area, or the catchment's groundwater flow system. Even at the smaller scales, the exchanges significantly influence solute...

This chapter presents some examples of nanoparticles formed by only a few microbial species that are cultivated in only a handful of laboratories worldwide. The investigations so far have just scratched the surface of the potential of the natural world to yield bionanomineral producers. While future research should involve screening...

This chapter provides an overview of the linkages between hydrology and biogeochemistry in terrestrial and aquatic systems. Selected topics include hydrological pathways on drainage basin slopes, mountain environments, within-river (or in-stream) processes, wetlands, groundwater (and groundwater–surface water interactions), and lakes. Beginning from catchment...

The time frame for natural attenuation of crude oil contamination in the subsurface has been studied for the last 27 years at a spill site located near Bemidji, Minnesota, USA. Data from thegroundwater contaminant plume show that dissolved benzene concentrations adjacent to the oil decreased by 50% between 1993 and...