Publications

A field experiment consisting of geophysical logging and tracer testing was conducted in a single well that penetrated a sand‐and‐gravel aquifer at the U.S. Geological Survey Toxic Substances Hydrology research site on Cape Cod, Massachusetts. Geophysical logs and flowmeter/pumping measurements were obtained to estimate vertical profiles of porosity ϕ, hydraulic conductivity K...

Nutrients and freshwater delivered by the Mississippi and Atchafalaya Rivers drive algal production in the northern Gulf of Mexico, which eventually results in the widespread occurrence of hypoxic bottom waters along the Louisiana and Texas coast. Researchers have demonstrated a relation between the extent of the hypoxic zone and the magnitude of streamflow, nutrient fluxes, and nutrient

OTEQ is a mathematical simulation model used to characterize the fate and transport of waterborne solutes in streams and rivers. The model is formed by coupling a solute transport model with a chemical equilibrium submodel. The solute transport model is based on OTIS, a model that considers the physical processes of advection, dispersion, lateral inflow, and transient storage. The...

Human health so often depends on the health of the environment and wildlife around us. The presence of naturally occurring or human environmental contaminants and the emergence of diseases transferred between animals and humans are growing concerns worldwide. The USGS is a source of natural science information vital for understanding the quantity and quality of our earth and living...

Beginning in the late 1990's, the U.S. Geological Survey began to develop analytical methods to detect, at concentrations less than 1 microgram per liter (ug/L), emerging water contaminants such as pharmaceuticals, personal-care chemicals, and a variety of other chemicals associated with various human and animal sources. During 1998-2005, the U.S. Geological Survey analyzed the following...

With the increased importance of water resources in the western United States and many areas worldwide, the remediation of impacts from historical mining becomes ever more important. A possible process of making decisions about remediation for a catchment might include identification of principal sources of metals in the catchment, classification of the sources as natural or...

Historical phosphorus (P) dynamics were studied using sediment cores from three oligotrophic, acidic lakes in Maine, USA. Long-term oligotrophy of these lakes is consistent with high sediment aluminum (as Al(OH)3) concentrations, as Al inhibits internal P loading, even under reducing conditions. The role of microbially-mediated reactions in controlling redox conditions was evaluated by...

Fate of radium (Ra) in liquid regeneration brine wastes from water softeners disposed to septic tanks in the New Jersey Coastal Plain was studied. Before treatment, combined Ra (226Ra plus 228Ra) concentrations (maximum, 1.54 Bq L−1) exceeded the 0.185 Bq L−1 Maximum Contaminant Level in 4 of 10 studied domestic-well waters (median pH, 4.90). At the water table downgradient from...

We explored the use of continuous waterborne electrical imaging (CWEI), in conjunction with fiber‐optic distributed temperature sensor (FO‐DTS) monitoring, to improve the conceptual model for uranium transport within the Columbia River corridor at the Hanford 300 Area, Washington. We first inverted resistivity and induced polarization CWEI data sets for distributions of electrical...

Isotopes are a potentially powerful component of monitoring and assessment programs aimed at quantifying and mitigating alterations to environments from human activities. In particular, isotopic techniques have proved useful for tracing sources and sinks of various pollutants in large river basins, wetlands, and airsheds. Many of these studies have been conducted at the regional to...

This 18-month field study addresses the seasonal and spatial patterns and processes controlling methylmercury (MeHg) production, bioaccumulation, and export from natural and agricultural wetlands of the Yolo Bypass Wildlife Area (YBWA). The data were collected in conjuntion with a Proposition 40 grant from the State Water Resources Control Board in support of the development of Best...

No abstract available.