Use of carbon-14 labeled trichloroethene to assess degradation potential in rock core microcosms.

In fractured rock aquifers contaminated with trichloroethene (TCE), the extent of groundwater plumes is impacted by degradation occurring within the rock matrix. The objective of this study was to evaluate TCE degradation in rock samples from three sites where in situ conditions may favor natural or enhanced attenuation. Intact rock core microcosms (94 total) were used to assess in situ conditions and enhancement by addition of lactate or lactate + sulfate.

Predicting COVID-19 Infected Individuals in a Defined Population from Wastewater RNA Data.

Wastewater surveillance of SARS-CoV-2 RNA has become an important tool for tracking the presence of the virus and serving as an early indicator for the onset of rapid transmission. Nevertheless, wastewater data are still not commonly used to predict the number of infected individuals in a sewershed. The main objective of this study was to calibrate a susceptible-exposed-infectious-recovered (SEIR) model using RNA copy rates in sewage (i.

Dual C-Br Isotope Fractionation Indicates Distinct Reductive Dehalogenation Mechanisms of 1,2-Dibromoethane in - and -Containing Cultures.

Brominated organic compounds such as 1,2-dibromoethane (1,2-DBA) are highly toxic groundwater contaminants. Multi-element compound-specific isotope analysis bears the potential to elucidate the biodegradation pathways of 1,2-DBA in the environment, which is crucial information to assess its fate in contaminated sites. This study investigates for the first time dual C-Br isotope fractionation during in vivo biodegradation of 1,2-DBA by two anaerobic enrichment cultures containing organohalide-respiring bacteria (i.

Effect of biostimulation and bioaugmentation on biodegradation of high concentrations of 1,4-dioxane.

1,4-Dioxane is a pervasive and persistent contaminant in numerous aquifers. Although the median concentration in most contaminant plumes is in the microgram per liter range, a subset of sites have contamination in the milligram per liter range. Most prior studies that have examined 1,4-dioxane concentrations in the hundreds of milligrams per liter range have been performed with industrial wastewater.

Anaerobic Biodegradation of Chloroform and Dichloromethane with a Enrichment Culture.

Chloroform (CF) and dichloromethane (DCM) are among the more commonly identified chlorinated aliphatic compounds found in contaminated soil and groundwater. Complete dechlorination of CF has been reported under anaerobic conditions by microbes that respire CF to DCM and others that biodegrade DCM. The objectives of this study were to ascertain if a commercially available bioaugmentation enrichment culture (KB-1 Plus CF) uses an oxidative or fermentative pathway for biodegradation of DCM and to determine if the products from DCM biodegradation can support organohalide respiration of CF to DCM in the absence of an exogenous electron donor.

COVID-19 wastewater epidemiology: a model to estimate infected populations.

Background: Wastewater-based epidemiology provides an opportunity for near real-time, cost-effective monitoring of community-level transmission of SARS-CoV-2. Detection of SARS-CoV-2 RNA in wastewater can identify the presence of COVID-19 in the community, but methods for estimating the numbers of infected individuals on the basis of wastewater RNA concentrations are inadequate.

Methods: This is a wastewater-based epidemiology study using wastewater samples that were collected weekly or twice a week from three sewersheds in South Carolina, USA, between either May 27 or June 16, 2020, and Aug 25, 2020, and tested for SARS-CoV-2 RNA.

Establishing the prevalence and relative rates of 1,4-dioxane biodegradation in groundwater to improve remedy evaluations.

Options for remediating 1,4-dioxane at groundwater sites are limited due to the physical-chemical properties of this compound. The relevance of natural attenuation processes for 1,4-dioxane was investigated through data from field, lab, and modeling efforts. The objectives were to use multiple lines of evidence for 1,4-dioxane biodegradation to understand the prevalence of this activity and evaluate convergence between lines of evidence.

Evaluation of natural attenuation of 1,4-dioxane in groundwater using a C assay.

Monitored Natural Attenuation (MNA) is a preferred remedy for sites contaminated with 1,4-dioxane due to its low cost and limited environmental impacts compared to active remediation. Having a robust estimate of the rate at which biodegradation occurs is an essential component of assessing MNA. In this study, an assay was developed using C-labeled 1,4-dioxane to measure rate constants for biodegradation based on accumulation of C products.

Chlorinated Ethene Degradation Rate Coefficients Simulated with Intact Sandstone Core Microcosms.

Abiotic transformation of trichloroethene (TCE) in fractured porous rock such as sandstone is challenging to characterize and quantify. The objective of this study was to estimate the pseudo first-order abiotic reaction rate coefficients in diffusion-dominated intact core microcosms. The microcosms imitated clean flow through a fracture next to a contaminated rock matrix by exchanging uncontaminated groundwater, unamended or lactate-amended, in a chamber above a TCE-infused sandstone core.

Impact of biological wastewater treatment on the reactivity of N-Nitrosodimethylamine precursors.

N-Nitrosodimethylamine (NDMA) is a probable human carcinogen which forms during chloramination of wastewater-impacted drinking waters. Municipal wastewater effluents are considered as major sources of NDMA precursors affecting downstream water quality. To evaluate the deactivation mechanisms and efficiencies of NDMA precursors during secondary treatment with the activated sludge (AS) process, NDMA formation potentials (FPs) of selected model precursor compounds and sewage components (i.

Simulation of in situ biodegradation of 1,4-dioxane under metabolic and cometabolic conditions.

Bioaugmentation is an option for aerobic remediation of groundwater contaminated with 1,4-dioxane. One approach uses microbes that cometabolize 1,4-dioxane following growth on a primary substrate (e.g.

Diffusion-Coupled Degradation of Chlorinated Ethenes in Sandstone: An Intact Core Microcosm Study.

Matrix diffusion must be considered when assessing natural attenuation and remediation of chlorinated ethenes in fractured porous bedrock aquifers. In this study, intact sandstone rock and groundwater from a trichloroethene (TCE)-contaminated site were used in microcosms (maintained for approximately 600 days) to simulate a single fracture-matrix system with a chamber at the top of the core allowing advection to represent fracture flow. Diffusion-coupled degradation with and without biostimulation were evaluated and compared to crushed-rock, batch microcosms.

Draft Genome Sequence of the 1,4-Dioxane-Degrading Bacterium Pseudonocardia dioxanivorans BERK-1.

strain BERK-1 grows aerobically with 1,4-dioxane as its sole substrate. Reported here is its draft genome sequence, with a size of 7.1 Mbp.

Aerobic biodegradation kinetics for 1,4-dioxane under metabolic and cometabolic conditions.

Biodegradation of 1,4-dioxane has been studied extensively, however, there is insufficient information on the kinetic characteristics of cometabolism by propanotrophs and a lack of systematic comparisons to metabolic biodegradation. To fill in these gaps, experiments were performed with suspended growth cultures to determine 16 Monod kinetic coefficients that describe metabolic consumption of 1,4-dioxane by Pseudonocardia dioxanivorans CB1190 and cometabolism by the propanotrophic mixed culture ENV487 and the propanotroph Rhodococcus ruber ENV425. Maximum specific growth rates were highest for ENV425, followed by ENV487 and CB1190.

Remediation of chlorinated ethenes in fractured sandstone by natural and enhanced biotic and abiotic processes: A crushed rock microcosm study.

Biostimulation was identified as a potential technology to treat a fractured sandstone aquifer contaminated with trichloroethene (TCE) and cis-1,2-dichloroethene (cis-DCE). Most of the mass of TCE and cis-DCE resides within the rock matrix and strategies to restore groundwater to pre-existing conditions are severely limited by back diffusion. A microcosm study using crushed rock and groundwater from the site was performed to assess biostimulation and natural attenuation.

Hydrogen Isotope Fractionation during the Biodegradation of 1,2-Dichloroethane: Potential for Pathway Identification Using a Multi-element (C, Cl, and H) Isotope Approach.

Even though multi-element isotope fractionation patterns provide crucial information with which to identify contaminant degradation pathways in the field, those involving hydrogen are still lacking for many halogenated groundwater contaminants and degradation pathways. This study investigates for the first time hydrogen isotope fractionation during both aerobic and anaerobic biodegradation of 1,2-dichloroethane (1,2-DCA) using five microbial cultures. Transformation-associated isotope fractionation values (ε) were -115 ± 18‰ (aerobic C-H bond oxidation), -34 ± 4‰ and -38 ± 4‰ (aerobic C-Cl bond cleavage via hydrolytic dehalogenation), and -57 ± 3‰ and -77 ± 9‰ (anaerobic C-Cl bond cleavage via reductive dihaloelimination).

Bench-scale evaluation of aerosol delivery for biostimulation and bioaugmentation in the vadose zone.

Aerosol delivery was evaluated for distributing biostimulation and bioaugmentation amendments in vadose zones. This technique involves transporting amendments as micron-scale aerosol droplets in injected gas. Microcosm experiments were designed to characterize reductive dechlorination of trichloroethene (TCE) under unsaturated conditions when delivering components as aerosols.

Biodegradation of high concentrations of halomethanes by a fermentative enrichment culture.

A fermentative enrichment culture (designated DHM-1) that grows on corn syrup was evaluated for its ability to cometabolically biodegrade high concentrations of chloroform (CF), carbon tetrachloride (CT), and trichlorofluoromethane (CFC-11). When provided with corn syrup and vitamin B12 (0.03 mol B12 per mol CF), DHM-1 grew and biodegraded up to 2,000 mg/L of CF in 180 days, with only minor transient accumulation of dichloromethane and chloromethane.

Isolation of an aerobic vinyl chloride oxidizer from anaerobic groundwater.

Vinyl chloride (VC) is a known human carcinogen and common groundwater contaminant. Reductive dechlorination of VC to non-toxic ethene under anaerobic conditions has been demonstrated at numerous hazardous waste sites. However, VC disappearance without stoichiometric production of ethene has also been observed at some sites and in microcosms.

Anaerobic oxidation of ethene coupled to sulfate reduction in microcosms and enrichment cultures.

Ethene is considered recalcitrant under anaerobic conditions, but biological reduction to ethane and oxidation to CO2 have been reported; however, little is known about these processes or the organisms carrying them out. In this report we describe sulfate dependent ethene consumption in microcosms prepared with sediments from a freshwater canal. A first dose of 0.

Kinetics of 1,2-dichloroethane and 1,2-dibromoethane biodegradation in anaerobic enrichment cultures.

1,2-Dichloroethane (1,2-DCA) and 1,2-dibromoethane (ethylene dibromide [EDB]) contaminate groundwater at many hazardous waste sites. The objectives of this study were to measure yields, maximum specific growth rates (μ), and half-saturation coefficients (K(S)) in enrichment cultures that use 1,2-DCA and EDB as terminal electron acceptors and lactate as the electron donor and to evaluate if the presence of EDB has an effect on the kinetics of 1,2-DCA dehalogenation and vice versa. Biodegradation was evaluated at the high concentrations found at some industrial sites (>10 mg/liter) and at lower concentrations found at former leaded-gasoline sites (1.

Anaerobic abiotic transformations of cis-1,2-dichloroethene in fractured sandstone.

A fractured sandstone aquifer at an industrial site is contaminated with trichloroethene to depths greater than 244 m. Field data indicate that trichloroethene is undergoing reduction to cis-1,2-dichloroethene (cDCE); vinyl chloride and ethene are present at much lower concentrations. Transformation of cDCE by pathways other than reductive dechlorination (abiotic and/or biotic) is of interest.

Efficacy of pentane, toluene, and benzene to support aerobic cometabolism of ethylene dibromide.

The ability of pentane, benzene, and toluene to support aerobic cometabolism of ethylene dibromide (1,2-dibromoethane, EDB) was evaluated. A pentane enrichment culture cometabolized EDB, with a transformation capacity of 0.35 μmol EDB/mg biomass (66.

Henry's law constants of chlorinated solvents at elevated temperatures.

Henry's law constants for 12 chlorinated volatile organic compounds (CVOCs) were measured as a function of temperature ranging from 8 to 93°C, using the modified equilibrium partitioning in closed system (EPICS) method. The chlorinated compounds include tetrachloroethylene, trichloroethylene, cis-1,2-dichloroethylene, vinyl chloride, 1,1,1-trichloroethane, 1,1-dichloroethane, 1,2-dichloroethane, chloroethane, carbon tetrachloride, chloroform, dichloromethane, and chloromethane. The variation in Henry's constants for these compounds as a function of temperature ranged from around 3-fold (chloroethane) to 30-fold (1,2-dichloroethane).