Publications

The Yellowstone River is a vital natural resource to the residents of southeastern Montana and is a primary source of water for irrigation and recreation and the primary source of municipal water for several cities. The Yellowstone River valley is the primary east-west transportation corridor through southern Montana. This complex of infrastructure makes the Yellowstone River especially...

[1] While it is widely recognized that highly permeable ‘large‐scale' fractures dominate chemical migration in many fractured aquifers, recent studies suggest that the pervasive ‘small‐scale’ fracturing once considered of less significance can be equally important for characterizing the spatial extent and residence time associated with transport processes. A detailed examination of...

Many national and regional groundwater studies have correlated land use "near" a well, often using a 500 m radius circle, with water quality. However, the use of a 500 m circle may seem counterintuitive given that contributing areas are expected to extend up-gradient from wells, and not be circular in shape. The objective of this study was to evaluate if a 500 m circle is adequate for...

No abstract available.

Four wells downgradient from a landfill near Elkhart, Indiana were sampled during 2000–2002 to evaluate the presence of waste-indicator and pharmaceutical compounds in landfill-leachate-affected ground water. Compounds detected in leachate-affected ground water included detergent metabolites (p-nonylphenol, nonylphenol monoethoxylate, nonylphenol diethoxylate, and octylphenol...

The giant garter snake (GGS; Thamnophis gigas) is a federally listed threatened species endemic to wetlands of the Central Valley of California. Habitat destruction has been the main factor in the decline of GGS populations, but the effects of contaminants on this species are unknown. To contribute to the recovery of these snakes, the U.S. Geological Survey (USGS) began studies of the...

Streamflow characteristics in the Yukon River Basin of Alaska and Canada have changed from 1944 to 2005, and some of the change can be attributed to the two most recent modes of the Pacific Decadal Oscillation (PDO). Seasonal, monthly, and annual stream discharge data from 21 stations in the Yukon River Basin were analyzed for trends over the entire period of record, generally spanning 4...

The Mauna Loa carbon dioxide record is an iconic symbol of the human capacity to alter the planet. Yet this record would not have been possible without the remarkable work of one man, Charles David Keeling. We describe three emergent themes that characterized his work: (1) his desire to study and understand the processes that control atmospheric CO2 and the global carbon cycle, (2) his...

Biodegradation of 17β-estradiol (E2), estrone (E1), and testosterone (T) was investigated in three wastewater treatment plant (WWTP) affected streams in the United States. Relative differences in the mineralization of [4-14C] substrates were assessed in oxic microcosms containing saturated sediment or water-only from locations upstream and downstream of the WWTP outfall in each system...

Short-term weathering rates (chemical denudation) of primary weathering products were derived from an analysis of fluxes in precipitation and streamwater. Rainfall, streamflow (runoff), and related water quality have been monitored at the Panola Mountain Research Watershed (PMRW) since 1985. Regression relations of stream solute concentration of major ions including weathering products...

Distribution and characteristics of heavy metals enrichment in sediment were surveyed including the bio-available form analyzed for assessment of the Luan River source water quality. The approaches of sediment quality guidelines (SQG), risk assessment code and Hakanson potential ecological risk index were used for the ecological risk assessment. According to SQG, The results show that in...

We recorded bulk electrical conductivity (σb) along a soil column during microbially-mediated selenite oxyanion reduction. Effluent fluid electrical conductivity and early time σb were modeled according to classic advective-dispersive transport of the nutrient medium. However, σb along the column exhibited strongly bimodal breakthrough which cannot be explained by changes in the...