Search USGS⌕ Search

SEARCH · Search USGS

Results for “Biodegradation”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

322 records · Page 18Linked to original sources
USGS2011

Guidance manual for forensic analysis of perchlorate in groundwater using chlorine and oxygen isotopic analyses

Increased health concerns about perchlorate (ClO4-) during the past decade and subsequent regulatory considerations have generated appreciable interest in source identification. The key objective of the isotopic techniques described in this guidance manual is to provide evidence concerning the origin of ClO4- in soils and groundwater and, more specifically, whether that ClO4- is synthetic or natural. Chlorine and oxygen isotopic analyses of ClO4- provide the primary direct approach whereby different sources of ClO4- can be distinguished from each other. These techniques measure the relative abundances of the stable isotopes of chlorine (37Cl and 35Cl) and oxygen (18O, 17O, and 16O) in ClO4- using isotope-ratio mass spectrometry (IRMS). In addition, the relative abundance of the radioactive chlorine isotope 36Cl is measured using accelerator mass spectrometry (AMS). Taken together, these measurements provide four independent quantities that can be used to distinguish natural and synthetic ClO4- sources, to discriminate different types of natural ClO4-, and to detect ClO4- biodegradation in the environment. Other isotopic, chemical, and geochemical techniques that can be applied in conjunction with isotopic analyses of ClO4- to provide supporting data in forensic studies are also described. This guidance manual is intended to provide details of the methodology used to (1) collect ClO4- samples from the environment, particularly from groundwater, which is the main medium of interest for ClO4- source identification; (2) purify the collected ClO4- samples; (3) conduct oxygen (O) and chlorine (Cl) isotopic analyses on the purified samples; and (4) determine probable sources using the resulting isotope data. Current practices for groundwater sampling and quality assurance for sample collection, purification, and measurement of Cl and O isotopes in ClO4- are provided. A detailed case study of source evaluation in groundwater on Long Island is given along with the current literature on the subject of ClO4- source discrimination. ClO4- in the environment is derived from both synthetic and natural sources. Synthetic ClO4- salts, including ammonium perchlorate (NH4ClO4) and potassium perchlorate (KClO4), have been widely used as oxidants by the military and aerospace industry. A variety of commercial products also contain synthetic ClO4-,including fireworks, matches, air bags, chlorine bleach, safety flares, perchloric acid, and chlorate herbicides. Historical disposal practices by the military, aerospace industry, and chemical manufacturers have resulted in groundwater and drinking water contamination with ClO4- in the United States. Isolated contamination from fireworks, road flares, explosives, and perchloric acid has also been reported. However, ClO4- is also a naturally occurring anion. It is present with sodium nitrate (NaNO3) in surficial deposits in the Atacama Desert of Chile at an average concentration of around 0.1% (by mass) of the total soluble salt, and these deposits (sometimes referred to as “Chilean caliche”) were widely used in the United States during the first half of the 20th century as a source of inorganic nitrogen fertilizer. Natural ClO4- that is not associated with Chilean fertilizers has also recently been detected in the vadose zone, groundwaters, and mineral deposits collected from the arid southwestern United States, including 155,000 km2 of groundwater in the Southern High Plains (SHP) of Texas and New Mexico. In addition to synthetic sources, natural ClO4- from both Chilean fertilizers and indigenous sources represents a potentially large source of ClO4- in groundwater and drinking water in the United States.

Report↗
USGS2011

Laboratory simulated transport of microcystin-LR and cylindrospermopsin in groundwater under the influence of stormwater ponds: implications for harvesting of infiltrated stormwater

Water shortages in the southeastern United States have led to a need for more intensive management and usage of stormwater for beneficial uses such as irrigation. Harvesting of infiltrated stormwater from horizontal wells in sandy aquifer sediments beneath stormwater ponds has emerged as an alternative in need of evaluation. Cyanobacteria may proliferate in stormwater ponds; cyanotoxins produced by these organisms represent potential public health concerns. Results of two, saturated flow, sand column experiments indicate breakthrough of microcystin-LR (MCLR) and cylindrospermopsin (CYL) within 1―2 pore volumes indicating little removal attributable to sorption. Concentration-based MCLR removal efficiencies up to 90% were achieved, which we hypothesize were predominantly due to biodegradation. In contrast, CYL removal efficiencies were generally less than 15%. On the basis of these results, removal of sandy soil in the stormwater pond bottom and addition of sorption media with greater binding affinities to cyanotoxins may enhance natural attenuation processes prior to water withdrawal.

Conference Paper↗
USGS2008

Subsurface fate and transport of sulfamethoxazole, 4-nonylphenol, and 17β-estradiol

Subsurface fate and transport of the antibiotic sulfamethoxazole (SX), the non-ionic surfactant degradation product 4-nonylphenol (NP), and the sex hormone 17β-estradiol (E2) were evaluated in a plume of contaminated groundwater at Cape Cod, Massachusetts, USA. The plume is the result of 60 years of wastewater treatment plant effluent disposal into rapid infiltration beds. Natural-gradient, in situ tracer experiments were used to evaluate subsurface transport of SX, NP, and E2 (injected at 300, 530, and 0.55 µg/L, respectively) relative to the conservative tracer bromide. Two geochemical zones were evaluated: (1) uncontaminated groundwater overlying the plume, and (2) contaminated groundwater within the plume that has recently become oxic after decades of anoxic conditions. The uncontaminated groundwater is characterized by a microbial community unacclimated to treated wastewater, whereas the contaminated groundwater is characterized by microbes acclimated to wastewater contaminants. Results from the tracer tests in both zones showed that the antibiotic SX was co-transported with the conservative tracer bromide, with little retardation or mass removal. In contrast, NP and E2, which are more hydrophobic and biodegradable, showed sorption (relative retardation factors ranged up to 5.9) and mass loss at both the uncontaminated and contaminated sites.

Conference Paper↗
USGS1988

Microbial degradation of crude oil and some model hydrocarbons

Research on microbial degradation of crude oil in the shallow subsurface at a spill site near Bemidji, Minn. (fig. C-l), began in 1983 (Hull, 1984; Chang and Ehrlich, 1984). The rate and extent of crude oil and model hydrocarbon biodegradation by the indigenous microbial community was measured in the laboratory at several concentrations of inorganic nutrients, conditions of oxygen availability, incubation temperatures, and incubation time.

Conference Paper↗
USGS1998

Ground-water age and atmospheric tracers: Simulation studies and analysis of field data from the Mirror Lake site, New Hampshire

The use of environmental tracers in characterization of ground-water systems is investigated through mathematical modeling of ground-water age and atmospheric tracer transport, and by a field study at the Mirror Lake site, New Hampshire. Theory is presented for modeling ground-water age using the advective-dispersive transport equation. The transport equation includes a zero-order source of unit strength, corresponding to the rate of aging, and can accommodate matrix diffusion and other exchange processes. The effect of temperature fluctuations and layered soils on transport of atmospheric gases to the water table is investigated using a one-dimensional numerical model of chlorofluorocarbon (CFC-11) transport. The nonlinear relation between temperature and Henry's Law coefficient (reflecting air/water phase partitioning) can cause the apparent recharge temperature to be elevated above the annual mean temperature where the water table is shallow. In addition, fine-grained soils can isolate the air phase in the unsaturated zone from the atmosphere. At the USGS' Mirror Lake, New Hampshire fractured-rock research site CFC concentrations near the water table are depleted where dissolved oxygen is low. CFC-11 and CFC-113 are completely absent under anaerobic conditions, while CFC-12 is as low as one-third of modern concentrations. Anaerobic biodegradation apparently consumes CFC's near the water table at this site. One area of active degradation appears to be associated with streamflow loss to ground water. Soil gas concentrations are generally close to atmospheric levels, although some spatial correlation is observed between depleted concentrations of CFC-11 and CFC-113 in soil gas and water-table samples. Results of unsaturated-zone monitoring indicate that recharge occurs throughout the year in the watershed, even during summer evapotranspiration periods, and that seasonal temperature fluctuations occur as much as 5 meters below land surface. Application of ground-water age and CFC-11 transport models to the large-scale ground-water system at Mirror Lake illustrates the similarities between age and chemical transport. Generally, bedrock porosities required to match observed apparent ages from CFC concentrations are high relative to porosities measured on cores. Although matrix diffusion has no effect on steady-state age, it can significantly reduce CFC concentrations in fractured rock in which the effective porosity is low.

New Hampshire↗
USGS2011

Long-term natural attenuation of crude oil in the subsurface

The time frame for natural attenuation of crude oil contamination in the subsurface has been studied for the last 27 years at a spill site located near Bemidji, Minnesota, USA. Data from the groundwater contaminant plume show that dissolved benzene concentrations adjacent to the oil decreased by 50% between 1993 and 2007. To assess how this decrease is related to benzene concentrations in the crude oil, samples of oil were bailed from floating oil in five wells and analysed for volatile components. Compared to reference oil collected from the pipeline in 1984, benzene concentrations in the well located farthest downgradient in the oil have decreased an average of 50%. Benzene and ethylbenzene depletion are linearly correlated with oil saturation in the pore space suggesting that dissolution is the primary removal mechanism and biodegradation within the oil body is insignificant.

Conference Paper↗
USGS2000

Primary food resources in the Sacramento-San Joaquin Delta

The Sacramento-San Joaquin River Delta, a complex mosaic of tidal freshwater habitats, is now a focus of ecosystem rehabilitation because of changes in critical functions associated with its geographic location at the landestuary interface. One of these functions is the production, transport, and transformation of organic matter that constitutes the “primary food supply,” that is, the food supply to the base of the food web. Interest in the primary food supply is motivated by evidence for sub-optimal food quantity or quality at trophic levels that support fish recruitment, including primary consumers such as clams, mysids, cladocerans, rotifers, and native copepods. We used the historical data set to examine the magnitudes of the most important organic matter sources for the Delta, the factors underlying their interannual and longer-term variability, and the implications of ecosystem rehabilitation actions for these sources. Here, we present a summary of the first phase of the analysis, including the quantitative importance of different organic matter sources and some of the hydrological controls on their year-to-year variability. The full report of this first phaseincluding data sources, the methods of calculation, and references, is in press elsewhere (Jassby and Cloern forthcoming). The historical data analysis is part of a larger project in which measurements of stable isotopes and biogeochemical markers, and experiments on organic matter biodegradation and zooplankton growth rates, are being used collectively to define the primary food resources and their quality.

California↗
USGS2004

Application of cross-borehole radar to monitor fieldscale vegetable old injection experiments for biostimulation

Cross-borehole radar methods were used to monitor a field-scale biostimulation pilot project at the Anoka County Riverfront Park (ACP), located downgradient of the Naval Industrial Reserve Ordnance Plant, in Fridley, Minnesota. The goal of the pilot project is to evaluate biostimulation using emulsified vegetable oil to treat ground water contaminated with chlorinated hydrocarbons. Vegetable oil is intended to serve as substrate to naturally occurring microbes, which ultimately break down chlorinated hydrocarbons into chloride, carbon dioxide, and water through oxidation-reduction reactions. In support of this effort, cross-borehole radar data were acquired by the U.S Geological Survey in five site visits over 1.5 years. This paper presents level-run (zero-offset profile) and time-lapse radar tomography data collected in multiple planes. Comparison of pre- and post-injection data sets provides valuable insights into the spatial and temporal distribution of both emulsified vegetable oil and also the extent of ground water with altered chemistry resulting from injections — information important for understanding microbial degradation of chlorinated hydrocarbons at the site. In order to facilitate data interpretation and test the effectiveness of radar for monitoring oil-emulsion placement and movement, three injection mixtures with different radar signatures were used: (1) vegetable oil emulsion, (2) vegetable oil emulsion with a colloidal iron tracer, and (3) vegetable oil emulsion with a magnetite tracer. Based on petrophysical modeling, mixture (1) is expected to increase radar velocity and decrease radar attenuation relative to background — a water-saturated porous medium; mixtures (2) and (3) are expected to increase radar velocity and also increase radar attenuation due to their greater electrical conductivity compared to native ground water. Radar slowness (inverse radar velocity) tomograms and level-run profiles show decreases in slowness in the vicinity of injection wells. Slowness anomalies are observed only in planes connected to injection wells, indicating that the emplaced emulsified vegetable oil does not migrate far after injection. In contrast to the localization of slowness anomalies, attenuation anomalies are observed in all level-run profiles, particularly those downgradient of the injection wells. Despite the expected signatures of different tracers, increases in attenuation are observed downgradient of all three injections; thus, we infer that the attenuation changes do not result from the iron tracers. One viable explanation for the observed attenuation changes is that products of oil-enhanced biodegradation (for example, ferrous iron) increase electrical conductivity of ground water and thus radar attenuation. Application of radar methods to data from the ACP demonstrated the utility of radar for monitoring biostimulation. Results of level-run and tomographic surveys identified (1) the distribution of emulsified vegetable oil, and (2) the distribution of ground water with oil-affected chemistry. Ongoing research efforts include simultaneous tomographic inversion of radar data from multiple planes, petrophysical modeling, geostatistical interpolation, and development of an integrated interpretation considering conventional borehole logs and surface-to-borehole radar data.

Minnesota↗
USGS2002

Environmental impacts of petroleum production: The fate of petroleum and other organics associated with produced water from the Osage-Skiatook Petroleum Environmental Research sites, Osage County, OK

We are involved in a multidisciplinary investigation to study the transport, fate, and natural attenuation of inorganic salts, trace metals, radionuclides and organic compounds present in produced water, and their impacts on soil, surface and ground water and the local ecosystem at the Osage-Skiatook Petroleum Environmental Research (OSPER) A and B sites, located in Osage County, OK. About one hectare of land at each of the OSPER A and B sites is affected by salt scarring, soil salinization and brine and petroleum contamination. The main environmental concern results because the sites are adjacent to Skiatook Lake, a 4250-hectare reservoir that provides drinking water to the local communities and is a major recreational fishery. Petroleum wells and tank batteries at the A site have been inactive for some time and the bulk of the hydrocarbon (now degraded and weathered oil) and produced water releases occurred more than 60 years ago. One pit at this site however, contains relatively fresh asphaltic oil and high salinity brine. The B site includes an active production tank battery and adjacent brine and oil pit, an inactive tank battery and an injection well with a small brine pit. For this study oil, gas and/or brine samples were obtained from several oil wells at the B site and areas adjoining the A and B sites, from the two active brine pits at the B site, from the asphaltic pit and adjacent weathered oil pit at the A site and from several of the 40 boreholes (1-71 m deep), recently drilled and completed. Water samples for dissolved organics were obtained from selected boreholes with high salinity water and measurable hydrocarbon gases in the unsaturated zone. Soil and rock core samples were obtained from these selected boreholes to determine the amount and composition of oil sorbed onto the sediments. Finally samples of sediments and/or water from these selected boreholes and from the brine and oil pits were obtained for bacterial characterization. Chemical analysis and bacterial determinations on the collected samples are continuing. Results completed to date show the crude oil source (samples from B and adjacent production wells) is a typical paraffinic-naphthenic light (API gravity of ~35) oil, containing n-alkanes as the dominant components. The four samples examined are identical in their maturity and chemical characteristics. Even though petroleum production is from shallow sandstones (300-600 m depth), these fresh oils show no sign of biodegradation, indicating that bacteria are unable to survive in the associated high salinity (~150,000 mg/L total dissolved solids) brine. Bacterial action, volatilization and water washing are likely responsible for the transformation of source oil to the surficial asphaltic and weathered oil observed at the A site. The leakage of oil with brine from the main active pit at the B site is indicated by the detection of a thin, but discrete oil phase in at least one borehole, the presence of hydrocarbon gases in several boreholes and the smell of oil in many sediment cores from the impacted area located down gradient from this pit. The measured concentrations of DOC, acetate and other organic acid anions, BTEX, phenols and other organics in the source brine are relatively low, but their values in water samples from the impacted areas are not yet available.

Oklahoma↗
USGS2019

Natural Attenuation in Source Zone and Groundwater Plume - Bemidji Crude Oil Spill

A long-term study of a 40-year-old crude oil spill provides insights about petroleum hydrocarbon natural attenuation processes and rates. In the source zone, fermentation coupled to methanogenesis is the dominant natural source zone depletion (NSZD) process, and most of the carbon mass exits the surface as CO2 efflux. Monitored natural attenuation (MNA) of the groundwater plume shows that benzene degradation is coupled to iron reduction and that the benzene plume is stable. A plume of hydrocarbon oxidation products measured as nonvolatile dissolved organic carbon (NVDOC) expanded ~20 m in 20 years. Most of the NVDOC is biodegraded by 200 m from the source, but optical data suggest there are components that persists for 300 m. Biological effects screening indicates decreasing biological effects with distance from the source.

Minnesota↗
USGS2015

Performance of an anaerobic, static bed, fixed film bioreactor for chlorinated solvent treatment

Anaerobic, fixed film, bioreactors bioaugmented with a dechlorinating microbial consortium were evaluated as a potential technology for cost effective, sustainable, and reliable treatment of mixed chlorinated ethanes and ethenes in groundwater from a large groundwater recovery system. Bench- and pilot-scale testing at about 3 and 13,500 L, respectively, demonstrated that total chlorinated solvent removal to less than the permitted discharge limit of 100 μg/L. Various planned and unexpected upsets, interruptions, and changes demonstrated the robustness and reliability of the bioreactor system, which handled the operational variations with no observable change in performance. Key operating parameters included an adequately long hydraulic retention time for the surface area, a constant supply of electron donor, pH control with a buffer to minimize pH variance, an oxidation reduction potential of approximately −200 millivolts or lower, and a well-adapted biomass capable of degrading the full suite of chlorinated solvents in the groundwater. Results indicated that the current discharge criteria can be met using a bioreactor technology that is less complex and has less downtime than the sorption based technology currently being used to treat the groundwater.

Biodegradation↗
USGS2005

Effectiveness of methyl bromide as a cargo fumigant for brown treesnakes

The effectiveness of methyl bromide as a fumigant for brown treesnake ( Boiga irregularis ) management was evaluated on Guam. Eighteen snakes in secured cloth bags were randomly positioned in a 47.7-m 3 tarpaulin-covered cargo container for each fumigation treatment. Methyl bromide treatments tested were: 24 g m −3 and and 12 g m −3 , both for 2-h and 1-h exposures. All treatments, except for 12 g m −3 for 1 h, resulted in 100% mortality. Two-hour exposures to methyl bromide at 24 and 12 g m −3 appear to be effective in killing brown treesnakes within reasonable time-frames for shippers under Guam field conditions.

International Biodeterioration and Biodegradation↗
USGS2015

Structural degradation of Thar lignite using MW1 fungal isolate: optimization studies

Biological degradation of low-rank coals, particularly degradation mediated by fungi, can play an important role in helping us to utilize neglected lignite resources for both fuel and non-fuel applications. Fungal degradation of low-rank coals has already been investigated for the extraction of soil-conditioning agents and the substrates, which could be subjected to subsequent processing for the generation of alternative fuel options, like methane. However, to achieve an efficient degradation process, the fungal isolates must originate from an appropriate coal environment and the degradation process must be optimized. With this in mind, a representative sample from the Thar coalfield (the largest lignite resource of Pakistan) was treated with a fungal strain, MW1, which was previously isolated from a drilled core coal sample. The treatment caused the liberation of organic fractions from the structural matrix of coal. Fungal degradation was optimized, and it showed significant release of organics, with 0.1% glucose concentration and 1% coal loading ratio after an incubation time of 7 days. Analytical investigations revealed the release of complex organic moieties, pertaining to polyaromatic hydrocarbons, and it also helped in predicting structural units present within structure of coal. Such isolates, with enhanced degradation capabilities, can definitely help in exploiting the chemical-feedstock-status of coal.

Thar coalfield↗
USGS2015

Characterization of the extremely arsenic-resistant Brevibacterium linens strain AE038-8 isolated from contaminated groundwater in Tucumán, Argentina

Brevibacterium linens AE038-8, isolated from As-contaminated groundwater in Tucumán (Argentina), is highly resistant to arsenic oxyanions, being able to tolerate up to 1 M As(V) and 75 mM As(III) in a complex medium. Strain AE038-8 was also able to reduce As(V) to As(III) when grown in complex medium but paradoxically it could not do this in a defined minimal medium with sodium acetate and ammonium sulfate as carbon and nitrogen sources, respectively. No oxidation of As(III) to As(V) was observed under any conditions. Three copies of the ars operon comprising arsenic resistance genes were found on B. linens AE038-8 genome. In addition to the well known arsC , ACR3 and arsR , two copies of the arsO gene of unknown function were detected.

Tucumán↗
USGS2002

Economic costs of electrical system instability and power outages caused by snakes on the Island of Guam

The Brown Tree Snake, Boiga irregularis , is an introduced species on Guam where it causes frequent electrical power outages. The snake's high abundance, its propensity for climbing, and use of disturbed habitats all contribute to interruption of Guam's electrical service and the activities that depend on electrical power. Snakes have caused more than 1600 power outages in the 20-yr period of 1978–1997 and most recently nearly 200 outages per year. Single outages spanning the entire island and lasting 8 or more hours are estimated to cost in excess of \$3,000,000 in lost productivity, but the costs of outages that involve only parts of the island or those of shorter durations are more difficult to quantify. Costs to the island's economy have exceeded $4.5 M per year over a 7-yr period without considering repair costs, damage to electrical equipment, and lost revenues. Snakes pose the greatest problem on high voltage transmission lines, on transformers, and inside electrical substations.

Guam↗
USGS1998

Damage reduction to ponderosa pine seedlings from northern pocket gophers by vegetation management through grass seeding and herbicide treatment

2,4-D herbicide treatment was applied to 2 treatment units to remove the forbs that are the preferred food of pocket gophers. One of these units also was seeded with grasses prior to the 2,4-D treatment. The effect of 2,4-D and grass seeding plus 2,4-D treatments were compared to an untreated control unit. Long-term monitoring (7 yr) was conducted on the 3 units for vegetative cover (7 yr), pocket gopher activity, and individual survival times and time until gopher damage for 2 cohorts of seedlings (5 and 6 yrs). The 2,4-D treatments greatly reduced vegetative cover of the forbs and seeding increased grass cover on the unit receiving that treatment. Pocket gopher activity was reduced somewhat on the unit receiving only the 2,4-D treatment and more so on the unit receiving grass seeding and 2,4-D, although gophers remained active to some degree throughout the study. Both cohorts of seedlings for both treatments units showed greater average times until gopher damage over seedlings on the control unit. However, seedling survival from all sources of mortality was not positively affected by the treatments for the first cohort of seedlings. The 2,4-D treatment appeared to have killed some of the seedlings; however, seedlings that survived the treatment were in a situation where they were less likely to be damaged by gophers and seemed to have improved growth rates.

Oregon↗