Publications

The mammalian aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that controls the expression of cytochrome P450 1A (CYP1A) genes in response to halogenated aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The natural ligand and normal physiologic function of this protein are as yet unknown. One approach to understanding AHR function and

Microtox® and Mutatox® were used to evaluate the acute toxicity and genotoxicity, respectively, of organic sediment extracts from Pensacola Bay and St. Andrew Bay, two estuaries that cover about 273 and 127 km2, respectively, along the Gulf coast of Florida, USA. The sensitivity and selectivity of these two bioluminescent toxicity assays were demonstrated in validation studies with over...

Measurements including soil respiration, soil moisture, soil temperature, and carbon export in suspended sediments from small watersheds were recorded at several field sites in northwestern Mississippi in support of hillslope process studies associated with the U.S. Geological Survey's Mississippi Basin Carbon Project (MBCP). These measurements were made to provide information about...

No abstract available.

Arsenic, Cd, Cu, Pb, Hg, and Zn were measured in sediments, biofilm, benthic macroinvertebrates, and fish from the Coeur d'Alene (CDA) River to characterize the pathway of metals transfer between these components. Metals enter the CDA Basin via tributaries where mining activities have occurred. In general, the ranking of food-web components from the greatest to smallest concentrations of...

The first phase of intensive data collection for the National Water-Quality Assessment (NAWQA) was completed during 1993−1995 in 20 major hydrologic basins of the United States. Groundwater land-use studies, designed to sample recently recharged groundwater (generally within 10 years) beneath specific land-use and hydrogeologic settings, are a major component of the groundwater quality...

Vertebrate embryos are particularly sensitive to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Identification of tissues that are susceptible to the adverse effects of TCDD is requisite for understanding the embryo toxic effects of TCDD. The objective of the present study was to quantitate the temporal appearance of and dose dependence of apoptosis in TCDD-exposed medaka embryos (Oryzias...

In 1986, Congress amended the Safe Drinking Water Act (SDWA) requiring the U.S. Environmental Protection Agency (USEPA) to promulgate disinfection requirements for all public-water supplies. The USEPA promulgated the Surface Water Treatment Rule (SWTR) in June 1989 to establish disinfection requirements for surface-water supplies and for ground water under the direct influence of surface...

A multi-functional spatial decision support system (SDSS) was,developed at the spatial analysis branch Of the National Wetlands Research Center, and the wildlife analysis module of the system was used to study habitat use by wintering pintail. We instrumented female pintails at Catahoula Lake, Louisiana, in October of 1992-94 and located the instrumented birds weekly through the...

Hurricanes are formidable forces that wreak havoc on society and nature alike. Mangrove ecosystems are especially vulnerable because they thrive in the intertidal zone of tropical regions where hurricanes originate and are most frequent. Because mangroves are found at the land-sea interface where hurricanes are often most intense, these coastal forests are subject to damage from both...

No abstract available.

No abstract available.