Publications

Denitrification is a critical process regulating the removal of bioavailable nitrogen (N) from natural and human-altered systems. While it has been extensively studied in terrestrial, freshwater, and marine systems, there has been limited communication among denitrification scientists working in these individual systems. Here, we compare rates of denitrification and controlling factors across a ra

No abstract available.

During 2004, a study to document the occurrence of herbicides and herbicide degradation products was conducted for 10 major Iowa rivers draining to the Missouri and Mississippi Rivers. Seventy-five water-quality samples were collected to measure isoxaflutole, acetamide, and triazine herbicides and their herbicide degradation products. An analytical method to measure isoxaflutole and its degradatio

A method for the determination of 69 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals on aquatic organisms in wastewater. This method also is useful for evaluating the effects of combined sanitary and storm-sewer overflow on the water quality of urban streams. T

This report contains water-quality and sediment-quality data from samples collected in the Yukon River Basin from March through September during the 2004 water year (WY). Samples were collected throughout the year at five stations in the basin (three on the main stem Yukon River, one each on the Tanana and Porcupine Rivers). A broad range of physical, chemical, and biological analyses are presente

In accordance with the mission of the U.S. Geological Survey (USGS) Toxic Substances Hydrology Program, a pesticide study was conducted during 2003–04 to determine the occurrence of the fungicide chlorothalonil and its degradation products at 22 surface-water sites in five Southern States. Water-quality samples were collected during the peanut-growing season (June–September) in 2003. During the pe

Veterinary antibiotics (VAs) are widely used in many countries worldwide to treat disease and protect the health of animals. They are also incorporated into animal feed to improve growth rate and feed efficiency. As antibiotics are poorly adsorbed in the gut of the animals, the majority is excreted unchanged in faeces and urine. Given that land application of animal waste as a supplement to fertil

No abstract available.

Mass spectrometry is an analytical technique used to measure the composition of a substance by isolating specific analyte components according to their individual atomic or molecular mass‐to‐charge ratios. Inorganic mass spectrometry is specifically used to determine the elemental and isotopic composition of the material being analyzed. The techniques are capable of the measurement of a range of c

Water-quality data were collected from sites in the Blue River Basin from July 1998 to October. Sites upstream from wastewater-treatment plants or the combined sewer system area had lower concentrations of total nitrogen, phosphorus, organic wastewater compounds, and pharmaceuticals, and more diverse aquatic communities. Sites downstream from wastewater-treatment plants had the largest concentrati

Water-quality data were collected from sites in the Blue River Basin from July 1998 to October. Sites upstream from wastewater-treatment plants or the combined sewer system area had lower concentrations of total nitrogen, phosphorus, organic wastewater compounds, and pharmaceuticals, and more diverse aquatic communities. Sites downstream from wastewater-treatment plants had the largest concentrati

In many natural and contaminated aquifers, geochemical processes result in the production or consumption of dissolved gases. In cases where methanogenesis or denitrification occurs, the production of gases may result in the formation and growth of gas bubbles below the water table. Near the water table, entrapment of atmospheric gases during water table rise may provide a significant source of O2