Publications

Whereas feeding inhibition caused by exposure to contaminants has been extensively documented, the underlying mechanism(s) are less well understood. For this study, the behavior of several key feeding processes, including ingestion rate and assimilation efficiency, that affect the dietary uptake of Cu were evaluated in the benthic grazer Lymnaea stagnalis following 4–5 h exposures to Cu adsorbed t

We measured total mercury (THg) and monomethyl mercury (MMHg) concentrations and mercury (Hg) isotopic compositions in sediment and aquatic organisms from the Yuba River (California, USA) to identify Hg sources and biogeochemical transformations downstream of a historical gold mining region. Sediment THg concentrations and δ202Hg decreased from the upper Yuba Fan to the lower Yuba Fan and the Feat

The awareness of insects as pollinators and indicators of environmental quality has grown in recent years, partially in response to declines in honey bee (Apis mellifera) populations. While most pesticide research has focused on honey bees, there has been less work on native bee populations. To determine the exposure of native bees to pesticides, bees were collected from an existing research area

Geophysical technologies have the potential to improve site characterization and monitoring in fractured rock, but the appropriate and effective application of geophysics at a particular site strongly depends on project goals (e.g., identifying discrete fractures) and site characteristics (e.g., lithology). No method works at every site or for every goal. New approaches are needed to identify a se

Polyoxyethylene tallow amine (POEA) is an inert ingredient added to formulations of glyphosate, the most widely applied agricultural herbicide. POEA has been shown to have toxic effects to some aquatic organisms making the potential transport of POEA from the application site into the environment an important concern. This study characterized the adsorption of POEA to soils and assessed its occurr

Pharmaceutical pollution in surface waters poses risks to human and ecosystem health. Wastewater treatment facilities are primary sources of pharmaceutical pollutants, but little is known about the factors that affect drugs entering the wastewater stream. This paper investigates the effects of student pharmaceutical use and disposal behaviors and an annual demographic shift on pharmaceutical pollu

Low-flow synoptic sampling campaigns are often used as the primary tool to characterize watersheds affected by mining. Although such campaigns are an invaluable part of site characterization, investigations which focus solely on low-flow conditions may yield misleading results. The objective of this paper is to demonstrate this point and elucidate the mechanisms responsible for the release of meta

Concentrations of dissolved organic matter (DOM) and ultraviolet/visible light absorbance decrease systematically as groundwater moves through the unsaturated zones overlying aquifers and along flowpaths within aquifers. These changes occur over distances of tens of meters (m) implying rapid removal kinetics of the chromophoric DOM that imparts color to groundwater. A one-compartment input-output

Explosives used in construction have been implicated as sources of NO3– contamination in groundwater, but direct forensic evidence is limited. Identification of blasting-related NO3– can be complicated by other NO3– sources, including agriculture and wastewater disposal, and by hydrogeologic factors affecting NO3– transport and stability. Here we describe a study that used hydrogeology, chemistry,

Water, bed sediment, and biota were sampled in streams from Butte to near Missoula, Montana, as part of a monitoring program in the upper Clark Fork Basin of western Montana. The sampling program was led by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to characterize aquatic resources in the Clark Fork Basin, with emphasis on trace elements associated w

Time-lapse electrical resistivity (ER) was used to capture the dilution of a seasonal pulse of acid mine drainage (AMD) contamination in the subsurface of a wetland downgradient of the abandoned Pennsylvania mine workings in central Colorado. Data were collected monthly from mid-July to late October of 2013, with an additional dataset collected in June of 2014. Inversion of the ER data shows the d

Methylation of tracer and ambient mercury (200Hg and 202Hg, respectively) equilibrated with four different natural organic matter (NOM) isolates was investigated in vivo using the Hg-methylating sulfate-reducing bacterium Desulfobulbus propionicus 1pr3. Desulfobulbus cultures grown fermentatively with environmentally representative concentrations of dissolved NOM isolates, Hg[II], and HS− were ass