Publications

Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sedimen

Mercury is a ubiquitous global environmental toxicant responsible for most US fish advisories. Processes governing mercury concentrations in rivers and streams are not well understood, particularly at multiple spatial scales. We investigate how insights gained from reach-scale mercury data and model simulations can be applied at broader watershed scales using a spatially and temporally explicit wa

Quantitative geochemical calculations are not possible without thermodynamic databases and considerable advances in the quantity and quality of these databases have been made since the early days of Lewis and Randall (1923), Latimer (1952), and Rossini et al. (1952). Oelkers et al. (2009) wrote, “The creation of thermodynamic databases may be one of the greatest advances in the field of geochemist

An in situ bioaugmentation (BA) experiment was conducted to understand processes controlling microbial dechlorination of trichloroethene (TCE) in groundwater at the Naval Air Warfare Center (NAWC), West Trenton, NJ. In the BA experiment, an electron donor (emulsified vegetable oil and sodium lactate) and a chloro-respiring microbial consortium were injected into a well in fractured mudstone of Tri

To determine the prevalence of mycotoxins in streams, 116 water samples from 32 streams and three wastewater treatment plant effluents were collected in 2010 providing the broadest investigation on the spatial and temporal occurrence of mycotoxins in streams conducted in the United States to date. Out of the 33 target mycotoxins measured, nine were detected at least once during this study. The det

Mineralogy is the link between ore formation and ore extraction. It is the most fundamental component of geomet programs, and the most important aspect of a life-of-project approach to mineral resource projects. Understanding orebodies is achieved by understanding the mineralogy and texture of the materials, throughout the process, because minerals hold the information required to unlock the valu

Fluids co-produced with oil and gas production (produced waters) are often brines that contain elevated concentrations of bromide. Bromide is an important precursor of several toxic disinfection by-products (DBPs) and the treatment of produced water may lead to more brominated DBPs. To determine if wastewater treatment plants that accept produced waters discharge greater amounts of brominated DBPs

The role of live vegetation in sediment methylmercury (MeHg) production and associated biogeochemistry was examined in three types of agricultural wetlands (domesticated or white rice, wild rice, and fallow fields) and adjacent managed natural wetlands (cattail- and bulrush or tule-dominated) in the Yolo Bypass region of California's Central Valley, USA. During the active growing season for each w

The vulnerability of public supply wells to chlorinated ethene (CE) contamination in part depends on the availability of naturally occurring organic carbon to consume dissolved oxygen (DO) and initiate reductive dechlorination. This was quantified by building a mass balance model of the Kirkwood-Cohansey aquifer, which is widely used for public water supply in New Jersey. This model was built by t

Characterization of ore and waste-rock material using automated quantitative micro-mineralogical techniques (e.g., QEMSCAN® and MLA) has the potential to complement traditional acid-base accounting and humidity cell techniques when predicting acid generation and metal release. These characterization techniques, which most commonly are used for metallurgical, mineral-processing, and geometallurgica

A multiagency pilot study on mussels (Mytilus spp.) collected at 68 stations in California revealed that 98% of targeted contaminants of emerging concern (CECs) were infrequently detectable at concentrations ⩽1 ng/g. Selected chemicals found in commercial and consumer products were more frequently detected at mean concentrations up to 470 ng/g dry wt. The number of CECs detected and their concentr

To expand the utility of the Mussel Watch Program, local, regional and state agencies in California partnered with NOAA to design a pilot study that targeted contaminants of emerging concern (CECs). Native mussels (Mytilus spp.) from 68 stations, stratified by land use and discharge scenario, were collected in 2009–10 and analyzed for 167 individual pharmaceuticals, industrial and commercial chemi