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Roux Associates
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Publications (46)
Source apportionment of observed PM2.5 concentrations is of growing interest as communities seek ways to improve their air quality. We evaluated publicly available PM2.5 data from the USEPA in the Dallas–Fort Worth metropolitan area to determine the contributions from various PM2.5 sources to the total PM2.5 observed. The approach combines interpol...
This document serves as supplemental information to Shapero et al. (2023), which is itself a comment on Nowell et al. (2022). Environmental Health Perspective’s publishing standards for article comments have strict word counts and do not allow the addition of new primary data analyses; therefore, this document provides an additional level of detail...
As the once carbon-fueled world of energy turns to renewables, there is one component which is essential for developing robust and resilient systems: batteries. Through the last two centuries, batteries have been steadily improving in functionality, size, environmental impact, and safety. The market for battery use today is in the multi-hundred bil...
Desert ecosystems are an environment of climatic extremes, to which many forms of life have adapted. These systems are characterized by scarce water and often sparsely vegetated lands where ecological adaptation to arid conditions has its underpinnings in the universal dependency on water to support life. Understanding the ecohydrological similarit...
While water sources that sustain many of the springs in the Mojave Desert have been poorly understood, desert wildlife and ecosystems can be highly dependent on such resources. With ever expanding use of desert groundwater, the effect of groundwater extraction on groundwater-dependent ecosystems in the Sonoran and Mojave Deserts is an ongoing conce...
Upfront consideration of historical operations and potentially valuable forensic information/data helps to ensuring the cleanup liability at dry cleaner sites can be equitably divided. While each site is different and requires site-specific evaluation, the associated environmental impacts from any given year of dry cleaning operations can vary sign...
Allocating costs for hazardous waste site cleanup among potentially responsible parties is unique to the specific circumstances, history, and data for the site. As such, distinct technical approaches are often needed considering the Gore and Torres factors to develop an overall allocation. These factors include both technical and nontechnical consi...
While the desert ecosystem is highly dependent on the water resources that sustain it, the Fish Slough spring complex is an arid, spring-dependent wetland undergoing a multidecadal decline in spring outflow. This evaluation updates the source water forensics of the Fish Slough Spring complex, a substantial spring complex in the northern Owens Valle...
Estimating groundwater recharge in arid or semiarid regions can be a difficult and complex task, since it is dependent on a highly variable set of spatial and temporal hydrologic parameters and processes that are dependent on the local climate, the land surface properties, and subsurface characteristics. As a result, traditional methods for estimat...
While water sources that sustain many of the springs in the Mojave Desert have been poorly understood, the desert ecosystem can be highly dependent on such resources. This evaluation updates the water resource forensics of Bonanza Spring, the largest spring in the southeastern Mojave Desert. The source of spring flow at Bonanza Spring was evaluated...
Base Realignment and Closure (“BRAC”) of military bases has occurred in waves over the last few decades. Many of these properties were operational through World War I, World War II, the Korean War, the Vietnam conflict, and into the modern Cold War. As part of the United States military's transfer of these properties to the local municipalities, wh...
The rapid evolution of legal and regulatory developments related to per- and polyfluoroalkyl substances (PFAS) has already resulted in some high-dollar legal settlements and is expected to generate numerous environmental claims. Currently, most major PFAS sites are associated with the primary chemical production of select PFAS and the application o...
The current conceptual hydrogeologic model established for source water to the Amargosa River was tested in order to help inform management decisions regarding the Amargosa River's Federal designation as Wild and Scenic through an Act of Congress. The limited availability of water in this region results in the critical need for effective management...
A system according to one embodiment includes a moisture trap for drying air; at least one of a first container and a second container; and a mechanism for at least one of: bubbling dried air from the moisture trap through a hydrogen peroxide solution in the first container for producing a hydrogen peroxide vapor, and passing dried air from the moi...
While it is well established that the dominant degradation mechanism for the chemical warfare agent, sarin, is hydrolysis via an SN2 mechanism in aqueous environments, the same cannot be said when hydrophilic or hydrophobic surfaces are present. Utilizing first-principles molecular dynamics simulations based on density functional theory, potential...
Decontaminating civilian facilities or large urban areas following an attack with Bacillus anthracis poses daunting challenges because of the lack of resources and proven technologies. Nevertheless, lessons learned from the 2001 cleanups together with advances derived from recent research have improved our understanding of what is required for effe...
Bench-scale testing was used to evaluate the efficacy of four decontamination formulations on typical indoor surfaces following exposure to the liquid chemical warfare agents sarin (GB), soman (GD), sulfur mustard (HD), and VX. Residual surface contamination on coupons was periodically measured for up to 24h after applying one of four selected deco...
In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility reuse and re-entry could require hours to multiple days. While restoration timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and deci...
In the event of a chemical terrorist attack on a transportation hub, post-event remediation and restoration activities necessary to attain unrestricted facility re-use and re-entry could require hours to multiple days. While timeframes are dependent on numerous variables, a primary controlling factor is the level of pre-planning and decision-making...
Researchers at the Institute of Environmental and Human Health (TIEHH) at Texas Tech University, USA, are developing a wipe for warfare agents and hazardous chemicals. The decontamination wipe, called Fibertect™, is said to have outperformed 30 different decontamination materials. It is made of an activated carbon core sandwiched between an absorbe...
New, non-particulate decontamination materials promise to reduce both military and civilian casualties by enabling individuals to decontaminate themselves and their equipment within minutes of exposure to chemical warfare agents or other toxic materials. One of the most promising new materials has been developed using a needlepunching nonwoven proc...
A compact and low-power microcantilever-based sensor array has been developed and used to detect various chemical vapor analytes. In contrast to earlier micro-electro-mechanical systems (MEMS) array sensors, this device uses the static deflection of piezoresistive cantilevers due to the swelling of glassy polyolefin coatings during sorption of chem...
Science-based decision making required robust and high-fidelity mechanistic data about the system dynamics and impacts of system changes. Alkaloid cyanotoxins have the characteristics to warrant consideration for their potential threat. Since insufficient information is available to construct a systems model for the alkaloid cyanotoxins, saxitoxins...
The Cyanotoxins Workgroup was charged with the identification and prioritization of research needs associated with: the identification of cyanotoxins; toxicokinetics and toxicodynamics of cyanotoxins; human susceptibility to the toxins; cyanobacterial genetics/omics and factors for inclusion in predictive models of toxin production; and risk reduct...
The United States is faced with having to address critical issues that have not been addressed in the past, as recent security interests have placed new and more pressing demands on the assessment of risk from exposure to potential threats resulting from deliberate contamination. Such assessments are the basis for decisions about future research pr...
New, nonparticulate decontamination materials promise to reduce both military and civilian casualties by enabling individuals to decontaminate themselves and their equipment within minutes of exposure to chemical warfare agents or other toxic materials. One of the most promising decontaminating materials has been developed using a needle-punching n...
Engineering the surface functional groups of silica aerogels has resulted in greatly enhanced separation capabilities. This approach is used to design a material that is effective at reducing the dissolved organic components of produced water. This study reports the initial results of removing dissolved hydrophobic organics using a hydrophobic (CH2...
Accelerator mass spectrometry (AMS) traces isotopically labeled biochemicals and provides significant new directions for understanding molecular kinetics and dynamics in biological systems. AMS traces low-abundance radioisotopes for high specificity but detects them with MS for high sensitivity. AMS reduces radiation exposure doses to levels safe f...
Laboratory experiments were conducted to determine environmental variables that affect the affinities and persistence of the nerve agent O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate (VX) at dilute concentrations in environmental matrices. Quantitative analyses of VX and its degradation products were performed using LC-MS. Batch hydro...
Direct measurement of tritium atoms by accelerator mass spectrometry (AMS) enables rapid low-activity tritium measurements from milligram-sized samples and permits greater ease of sample collection, faster throughput, and increased spatial and/or temporal resolution. Because existing methodologies for quantifying tritium have some significant limit...
Annual tritium exposures were reconstructed using tree cores from Pinus jeffreyi and Eucalyptus globulus near a tritiated water vapor release stack. Both tritium (3H) and carbon-14 (14C) from the wood were measured from milligram samples using accelerator mass spectrometry. Because the annual nature of the eucalyptus tree rings was in doubt, 14C me...
Two sediment cores were collected from a marina in the San Francisco Bay to characterize historical sediment contamination resulting from the direct discharge of industrial wastewater from Naval Air Station Alameda. Depth profiles of trace metals, petroleum hydrocarbons, and radionuclides were determined with a 12-cm spacing down to a depth of 120...
The capability to prepare samples accurately and reproducibly for analysis of tritium (3H) content by accelerator mass spectrometry (AMS) greatly facilitates isotopic tracer studies in which attomole levels of 3H can be measured in milligram-sized samples. A method has been developed to convert the hydrogen of organic samples to a solid, titanium h...
There are numerous instances where historical exposures to contaminants can determine future health impacts, but limited means exist to reconstruct those exposures from current measurements and models. The National Tritium Labeling Facility at Lawrence Berkeley National Laboratory (LBNL) has released tritiated water into the atmosphere through an a...
Public concerns over the health effects associated with low-level and long-term exposure to tritium released from industrial point sources have generated the demand for better methods to evaluate historical tritium exposure levels for these communities. The cellulose of trees accurately reflects the tritium concentration in the source water and may...
Tritium (3H) is a radioisotope that is extensively utilized in biological and environmental research. For biological research, 3H is generally quantified by liquid scintillation counting requiring gram-sized samples and counting times of several hours. For environmental research, 3H is usually quantified by 3He in-growth which requires gram-sized s...
Quantitative information on the environmental transport and fate of organophosphorus nerve agents has been limited to studies conducted at high concentration representative of acute doses (Munroe et al. 1999). Nerve agents have relatively rapidly degradation rates at acute levels, and first order degradation pathways and half-lives have been charac...
Man-made organophosphorus compounds have been widely distributed throughout our environment as pesticides since their development during and after WWII. Many important studies have documented their relative persistence and toxicity. Development and use of some organophosphorus compounds as nerve agents gave rise to a separate but parallel effort to...
The early detection of the deliberate biological and chemical contamination of water distribution systems is a necessary capability for securing the nation's water supply. Current and emerging early-detection technology capabilities and shortcomings need to be identified and assessed to provide government agencies and water utilities with an improv...
This slide presentation outlines information on a technology acquisition strategy for the security of water distribution networks. The Department of Homeland Security (DHS) has tasked a multi-laboratory team to evaluate current and future needs to protect the nation's water distribution infrastructure by supporting an objective evaluation of curren...