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The compatibility of dense non-aqueous phase liquids (DNAPLs), trichloroethylene (TCE), methylene chloride (MC), and creosote with commercially available sodium bentonite pellets was evaluated using stainless steel, double-ring, falling-head permeameters. The Hydraulic conductiv...

Several questions and uncertainties hinder widespread applications of geophysical methods for environmental and groundwater investigations. This contribution identifies three main impediments to the application of geophysics for environmental and groundwater investigations and pr...

Effects-based bioassays are expeditious and economic non-targeted chemical analysis tools frequently used in preliminary stages of water quality monitoring efforts, or as part of effects-directed analysis. Using in vitro effects-based methods, we previously detected biological ac...

1,4-Dioxane was one of the first 10 chemical substances undergoing the TSCA risk evaluation process after passage of the Frank R. Lautenberg Chemical Safety for the 21st Century Act, which amended TSCA in 2016. The 2023 Draft Supplement includes evaluation of additional conditio...

Many factors, including microbiome structure and activity in the drinking water distribution system (DWDS), affect the colonization potential of opportunistic pathogens. The present study aims to describe the dynamics of active bacterial communities in DWDS and identify the facto...

Soil gas samples are collected to evaluate human health risk from vapor intrusion into homes and other buildings. In order to meet risk assessment goals, the analytical reporting limit for many compounds of concern are down to part per billion ranges. The appropriate sampling t...

1,4-dioxane is a likely human carcinogen and has been found in groundwater and drinking water supplies throughout the United States. Historically, 90% of 1,4-dioxane production was used as a stabilizer in chlorinated solvents, such as 1,1,1-trichloroethane (TCA). The physical and...

Desalination drinking water systems and industrial processes generating high salinity streams require practical brine management options for disposal and/or treatment.  Treatment most often involves large capacity brine concentrating processes, on the order of 2000 m3/day, that r...

The U.S. Environmental Protection Agency’s (EPA) Office of Groundwater and Drinking Water (OGWDW) through the Office of Water (OW) is responsible for protecting the nation’s drinking water from known and emerging contaminants. Historically, OGWDW has used the Drinking...

This report focuses on the problem of diving plumes, a term which generally refers to plumes that go deeper into aquifers with distances from their sources. This document presents the mathematical basis of software for real-time development and refinement of site conceptual model...

Invited "mini" science presentation for the National EPA-Tribal Science Council Summer 2023 Meeting, co-hosted by the Santee Sioux Nation of Nebraska and the Ponca Tribe of Nebraska. They identified nutrients, groundwater, wetlands and wastewater treatment as issues of ...

ABSTRACT: We previously detected biological activity, indicative of endocrine disrupting compounds, in surface and source waters. However, the paucity of chemical contaminant occurrence data in unmonitored private-supply point-of-use (POU) tapwater, as well as the potential for u...

In the United States, onshore oil and gas extraction operations generate an estimated one trillion gallons of produced water annually, making it the largest waste stream associated with upstream development of petroleum hydrocarbons by volume. Produced water is defined as the inc...

Enhanced Aquifer Recovery (EAR) conveys stormwater runoff, wastewater or other source water into the subsurface for storage, potential reuse, and augment water supplies. The potential impacts to groundwater quality from the use of EAR are poorly understood. This presentation will...

The U.S. Environmental Protection Agency’s (EPA’s) Homeland Security Research Program (HSRP) conducts research to detect, respond to, and recover from the impacts of terrorist attacks, accidental contamination and natural disasters on the nation's water and wastewater infrastruct...

QUAL2K (or Q2K) is a river and stream water quality model that is intended to represent a modernized version of the QUAL2E (or Q2E) model (Brown and Barnwell 1987). Q2K is similar to Q2E in the following respects:<ul> <li>One dimensional. The channel is well-mixed vertically a...

Soil vapor extraction (SVE) can be applied for remediation, and also as an alternative to sub-slab depressurization (SSD) for vapor intrusion (VI) mitigation. This study compares capital, operation, and treatment costs of SVE and SSD systems using data collected during a multi-ye...

In response to a request for scientific support to assess whether chloride in Bitter and Killpecker Creeks in Wyoming may be naturally high, warranting site-specific criteria, the USEPA Office of Research and Development is providing for USEPA Region 8 use a characterization of b...

The Surface Water Treatment Rule (40 CFR 141.74 (a)(2)) requires a detectable disinfectant residual in the distribution system, measured as free or total chlorine, chlorine dioxide or ozone. Total chlorine includes free and combined chlorine. Combined chlorine includes inorganic ...

We present the results of a lab-scaled feasibility study to assess the performance of electrical resistivity tomography for detection, characterization, and monitoring of fuel grade ethanol releases to the subsurface.&nbsp; Further, we attempt to determine the concentration distr...

Impact of underground storage tank leaks on water quality of small drinking water systems.

Groundwater quality is often evaluated using microbial indicators. This study examines data from 12 international groundwater studies (conducted 1992-2013) of 718 public drinking-water systems located in a range of hydrogeological settings. Focus was on testing the value of indic...

Bacteriophages have been used in soil column studies for the last several decades as surrogates to study the fate and transport behavior of enteric viruses in groundwater. However, recent studies have shown that the transport behavior of bacteriophages and enteric viruses in poro...

Nonperennial streams dominate global river networks and are increasing in occurrence across space and time. When surface flow ceases or the surface water dries, flow or moisture can be retained in the subsurface sediments of the hyporheic zone, supporting aquatic communities and ...

<p>EPA announced the release of VELMA 2.1 Model and accompanying supplemental user's guide (Apr 2022) on the EPA website. EPA's VELMA tool helps assessor's model effective decisions for a wide array of environmental issues. It is a spatially explicit ecohydrological watershed mod...