Geology topics

Laura E. Hubbard

Publications and source records attributed to Laura E. Hubbard.

33 records · Page 2Linked to original sources

USGS2018

A surrogate regression approach for computing continuous loads for the tributary nutrient and sediment monitoring program on the Great Lakes

Water quality (WQ) in many Great Lake tributaries has been degraded (increased nutrient and sediment concentrations) due to changes in their watersheds, resulting in downstream eutrophication. As part of the Great Lakes Water Quality Agreement, specific goals were established for loading of specific constituents (e.g., phosphorus). In 2010, the Great Lakes Restoration Initiative was launched to identify problem areas, accelerate restoration efforts, and track their progress. In 2011, the U.S. Geological Survey established a monitoring program on 30 tributaries to the lakes, representing ~ 46% of the U.S. draining area and the spectrum of land uses. Discrete measurements of nutrients and suspended sediment, and continuous measurements of flow and WQ surrogates (turbidity, temperature, specific conductance, pH, and dissolved oxygen) are being collected in these tributaries to document their WQ and estimate continuous (5-min) loading. To estimate loadings, two regression models were developed for each constituent for each site: one using continuous flow and a seasonality factor; and one using flow, seasonality, and continuous surrogates. Variables included in the final models for each constituent were chosen from the explanatory variables that worked “best” for all sites. In computing loads, when continuous surrogate data were unavailable for short periods, loads were computed using the flow and seasonality models. Prediction intervals for all loads were calculated using results from both models. These results provide a better understanding of short-term variability and long-term changes in loading affecting the environmental health of the Great Lakes than traditional regression techniques that employ only flow and seasonality parameters.

Great Lake↗

USGS2017

Flood-frequency characteristics of Wisconsin streams

Flood-frequency characteristics for 360 gaged sites on unregulated rural streams in Wisconsin are presented for percent annual exceedance probabilities ranging from 0.2 to 50 using a statewide skewness map developed for this report. Equations of the relations between flood-frequency and drainage-basin characteristics were developed by multiple-regression analyses. Flood-frequency characteristics for ungaged sites on unregulated, rural streams can be estimated by use of the equations presented in this report. The State was divided into eight areas of similar physiographic characteristics. The most significant basin characteristics are drainage area, soil saturated hydraulic conductivity, main-channel slope, and several land-use variables. The standard error of prediction for the equation for the 1-percent annual exceedance probability flood ranges from 56 to 70 percent for Wisconsin Streams; these values are larger than results presented in previous reports. The increase in the standard error of prediction is likely due to increased variability of the annual-peak discharges, resulting in increased variability in the magnitude of flood peaks at higher frequencies. For regulated streams, a graphical method for estimating flood-frequency characteristics was developed from the relations of discharge and drainage area for selected annual exceedance probabilities. Graphs for the major regulated streams in Wisconsin are presented in the report.

Wisconsin↗

USGS2017

Highlighting the complexities of a groundwater pilot study during an avian influenza outbreak: Methods, lessons learned, and select contaminant results

The highly pathogenic avian influenza (H5N2) outbreak in the Midwestern United States (US) in 2015 was historic due to the number of birds and poultry operations impacted and the corresponding economic loss to the poultry industry and was the largest animal health emergency in US history. The U.S. Geological Survey (USGS), with the assistance of several state and federal agencies, aided the response to the outbreak by developing a study to determine the extent of virus transport in the environment. The study goals were to: develop the appropriate sampling methods and protocols for measuring avian influenza virus (AIV) in groundwater, provide the first baseline data on AIV and outbreak- and poultry-related contaminant occurrence and movement into groundwater, and document climatological factors that may have affected both survival and transport of AIV to groundwater during the months of the 2015 outbreak. While site selection was expedient, there were often delays in sample response times due to both relationship building between agencies, groups, and producers and logistical time constraints. This study's design and sampling process highlights the unpredictable nature of disease outbreaks and the corresponding difficulty in environmental sampling of such events. The lessons learned, including field protocols and approaches, can be used to improve future research on AIV in the environment.

Iowa↗

USGS2016

U.S. Geological Survey science strategy for highly pathogenic avian influenza in wildlife and the environment (2016–2020)

Introduction Through the Science Strategy for Highly Pathogenic Avian Influenza (HPAI) in Wildlife and the Environment, the USGS will assess avian influenza (AI) dynamics in an ecological context to inform decisions made by resource managers and policymakers from the local to national level. Through collection of unbiased scientific information on the ecology of AI viruses and wildlife hosts in a changing world, the U.S. Geological Survey (USGS) will enhance the development of AI forecasting tools and ensure this information is integrated with a quality decision process for managing HPAI. The overall goal of this USGS Science Strategy for HPAI in Wildlife and the Environment goes beyond documenting the occurrence and distribution of AI viruses in wild birds. The USGS aims to understand the epidemiological processes and environmental factors that influence HPAI distribution and describe the mechanisms of transmission between wild birds and poultry. USGS scientists developed a conceptual model describing the process linking HPAI dispersal in wild waterfowl to the outbreaks in poultry. This strategy focuses on five long-term science goals, which include: Science Goal 1—Augment the National HPAI Surveillance Plan; Science Goal 2—Determine mechanisms of HPAI disease spread in wildlife and the environment; Science Goal 3—Characterize HPAI viruses circulating in wildlife; Science Goal 4—Understand implications of avian ecology on HPAI spread; and Science Goal 5—Develop HPAI forecasting and decision-making tools. These goals will help define and describe the processes outlined in the conceptual model with the ultimate goal of facilitating biosecurity and minimizing transfer of diseases across the wildlife-poultry interface. The first four science goals are focused on scientific discovery and the fifth goal is application-based. Decision analyses in the fifth goal will guide prioritization of proposed actions in the first four goals.

Open-File Report↗

USGS2016

Dairy-impacted wastewater is a source of iodinated disinfection byproducts in the environment

Iodinated disinfection byproducts (DBPs) are among the most toxic DBPs, but they are not typically measured in treated water. Iodinated DBPs can be toxic to humans, and they also have the potential to affect aquatic communities. Because of the specific use of iodine and iodine-containing compounds in dairies, such livestock operations can be a potential source of iodinated DBPs in corresponding receiving water bodies. DBPs [trihalomethanes (THMs), including iodinated THMs] were measured within dairy processing facilities (milking and cheese manufacturing) and surface waters that receive dairy-impacted effluents [either directly from the dairy or through wastewater treatment plants (WWTPs)] in three areas of the United States (California, New York, and Wisconsin). Iodo-THMs comprised 15−29% of the total THMs in surface water near WWTP effluents that were impacted by dairy waste and 0−100% of the total THMs in samples from dairy processing facilities.

California, New York, Wisconsin↗

USGS2016

Effect of variable annual precipitation and nutrient input on nitrogen and phosphorus transport from two Midwestern agricultural watersheds

Precipitation patterns and nutrient inputs affect transport of nitrate (NO 3 -N) and phosphorus (TP) from Midwest watersheds. Nutrient concentrations and yields from two subsurface-drained watersheds, the Little Cobb River (LCR) in southern Minnesota and the South Fork Iowa River (SFIR) in northern Iowa, were evaluated during 1996–2007 to document relative differences in timings and amounts of nutrients transported. Both watersheds are located in the prairie pothole region, but the SFIR exhibits a longer growing season and more livestock production. The SFIR yielded significantly more NO 3 -N than the LCR watershed (31.2 versus 21.3 kg NO 3 -N ha − 1 y − 1 ). The SFIR watershed also yielded more TP than the LCR watershed (1.13 versus 0.51 kg TP ha − 1 yr − 1 ), despite greater TP concentrations in the LCR. About 65% of NO 3 -N and 50% of TP loads were transported during April–June, and < 20% of the annual loads were transported later in the growing season from July–September. Monthly NO 3 -N and TP loads peaked in April from the LCR but peaked in June from the SFIR; this difference was attributed to greater snowmelt runoff in the LCR. The annual NO 3 -N yield increased with increasing annual runoff at a similar rate in both watersheds, but the LCR watershed yielded less annual NO 3 -N than the SFIR for a similar annual runoff. These two watersheds are within 150 km of one another and have similar dominant agricultural systems, but differences in climate and cropping inputs affected amounts and timing of nutrient transport.

Science of the Total Environment↗

USGS2016

Pre/post-closure assessment of groundwater pharmaceutical fate in a wastewater‑facility-impacted stream reach

Pharmaceutical contamination of contiguous groundwater is a substantial concern in wastewater-impacted streams, due to ubiquity in effluent, high aqueous mobility, designed bioactivity, and to effluent-driven hydraulic gradients. Wastewater treatment facility (WWTF) closures are rare environmental remediation events; offering unique insights into contaminant persistence, long-term wastewater impacts, and ecosystem recovery processes. The USGS conducted a combined pre/post-closure groundwater assessment adjacent to an effluent-impacted reach of Fourmile Creek, Ankeny, Iowa, USA. Higher surface-water concentrations, consistent surface-water to groundwater concentration gradients, and sustained groundwater detections tens of meters from the stream bank demonstrated the importance of WWTF effluent as the source of groundwater pharmaceuticals as well as the persistence of these contaminants under effluent-driven, pre-closure conditions. The number of analytes (110 total) detected in surface water decreased from 69 prior to closure down to 8 in the first post-closure sampling event approximately 30 d later, with a corresponding 2 order of magnitude decrease in the cumulative concentration of detected analytes. Post-closure cumulative concentrations of detected analytes were approximately 5 times higher in proximal groundwater than in surface water. About 40% of the 21 contaminants detected in a downstream groundwater transect immediately before WWTF closure exhibited rapid attenuation with estimated half-lives on the order of a few days; however, a comparable number exhibited no consistent attenuation during the year-long post-closure assessment. The results demonstrate the potential for effluent-impacted shallow groundwater systems to accumulate pharmaceutical contaminants and serve as long-term residual sources, further increasing the risk of adverse ecological effects in groundwater and the near-stream ecosystem.

Iowa↗

USGS2016

Understanding the hydrologic impacts of wastewater treatment plant discharge to shallow groundwater: Before and after plant shutdown

Effluent-impacted surface water has the potential to transport not only water, but wastewater-derived contaminants to shallow groundwater systems. To better understand the effects of effluent discharge on in-stream and near-stream hydrologic conditions in wastewater-impacted systems, water-level changes were monitored in hyporheic-zone and shallow-groundwater piezometers in a reach of Fourmile Creek adjacent to and downstream of the Ankeny (Iowa, USA) wastewater treatment plant (WWTP). Water-level changes were monitored from approximately 1.5 months before to 0.5 months after WWTP closure. Diurnal patterns in WWTP discharge were closely mirrored in stream and shallow-groundwater levels immediately upstream and up to 3 km downstream of the outfall, indicating that such discharge was the primary control on water levels before shutdown. The hydrologic response to WWTP shutdown was immediately observed throughout the study reach, verifying the far-reaching hydraulic connectivity and associated contaminant transport risk. The movement of WWTP effluent into alluvial aquifers has implications for potential WWTP-derived contamination of shallow groundwater far removed from the WWTP outfall.

Iowa↗

USGS2016

The effect of restored and native oxbows on hydraulic loads of nutrients and stream water quality

The use of oxbow wetlands has been identified as a potential strategy to reduce nutrient transport from agricultural drainage tiles to streams in Iowa. In 2013 and 2014, a study was conducted in north-central Iowa in a native oxbow in the Lyons Creek watershed and two restored oxbow wetlands in the Prairie Creek watershed (Smeltzer west and Smeltzer east) to assess their effectiveness at reducing nitrogen and phosphorus loads. The tile line inlets carrying agricultural runoff to the oxbows, the outfall from the oxbows, and the surface waters in the streams receiving the outfall water were monitored for discharge and nutrients from February 2013 to September 2015. Smeltzer west and east also had four monitoring wells each, two in the upland and two between the oxbow and Prairie Creek to monitor surface water-groundwater interaction. The Smeltzer west and east oxbow sites also were instrumented to continuously measure the nitrate concentration. Rainfall was measured at one Lyons Creek and one Smeltzer site. Daily mean nitrate-N concentrations in Lyons Creek in 2013 ranged from 11.8 mg/L to 40.9 mg/L, the median daily mean nitrate-N concentration was 33.0 mg/L. Daily mean nitrate-N concentrations in Prairie Creek in 2013 ranged from 0.07 mg/L in August to 32.2 mg/L in June. In 2014, daily mean nitrate-N concentrations in Prairie Creek ranged from 0.17 mg/L in April to 26.7 mg/L in July; the daily mean nitrate-N concentration for the sampled period was 9.78 mg/L. Nutrient load reduction occurred in oxbow wetlands in Lyons and Prairie Creek watersheds in north-central Iowa but efficiency of reduction was variable. Little nutrient reduction occurred in the native Lyons Creek oxbow during 2013. Concentrations of all nutrient constituents were not significantly (P>0.05, Wilcoxon rank sum) different in water discharging from the tile line than in water leaving the Lyons Creek oxbow. A combination of physical features and flow conditions suggest that the residence time of water in the oxbow may not have been sufficient to allow for removal of substantial amounts of nutrients. Approximately 54 percent less nitrate-N was measured leaving the Smeltzer west oxbow than was measured entering from a small 6-inch field tile. The efficiency of nitrate-N removal in the oxbow was not able to be definitively quantified as other hydrologic factors such as overland and groundwater flow into and through the oxbow were not addressed and may provide alternative routes for nutrient transport. Damage to the Smeltzer east oxbow outfall weir prevented analysis of its nutrient load reduction capability. The study provides important information to managers and land owners looking for strategies to reduce nutrient transport from fields. Additional research is needed to understand how increased discharge from larger field tiles and drainage district mains may influence the efficiency of nutrient reduction in relation to the size, type, and landscape setting of a wetland.

Iowa↗

USGS2015

Genes indicative of zoonotic and swine pathogens are persistent in stream water and sediment following a swine manure spill

Manure spills to streams are relatively frequent, but no studies have characterized stream contamination with zoonotic and veterinary pathogens, or fecal chemicals, following a spill. We tested stream water and sediment over 25 days and downstream for 7.6 km for: fecal indicator bacteria (FIB); the fecal indicator chemicals cholesterol and coprostanol; 20 genes for zoonotic and swine-specific bacterial pathogens by presence/absence polymerase chain reaction (PCR) for viable cells; one swine-specific Escherichia coli toxin gene ( STII ) by quantitative PCR (qPCR); and nine human and animal viruses by qPCR, or reverse-transcriptase qPCR. Twelve days post-spill, and 4.2 km downstream, water concentrations of FIB, cholesterol, and coprostanol were 1-2 orders of magnitude greater than those detected before, or above, the spill, and genes indicating viable zoonotic or swine-infectious Escherichia coli , were detected in water or sediment. STII increased from undetectable before, or above the spill, to 10 5 copies/100 mL water 12 days post-spill. Thirteen of 14 water (8/9 sediment) samples had viable STII -carrying cells post-spill. Eighteen days post-spill porcine adenovirus and teschovirus were detected 5.6 km downstream. Sediment FIB concentrations (per gram wet weight) were greater than in water, and sediment was a continuous reservoir of genes and chemicals post-spill. Constituent concentrations were much lower, and detections less frequent, in a runoff event (200 days post-spill) following manure application, although the swine-associated STII and stx 2e genes were detected. Manure spills are an underappreciated pathway for livestock-derived contaminants to enter streams, with persistent environmental outcomes, and the potential for human and veterinary health consequences.

Iowa↗

USGS2015

2013 Survey of Iowa groundwater and evaluation of public well vulnerability classifications for contaminants of emerging concern

Studies in Iowa have long documented the vulnerability of wells with less than 50 feet (15 meters) of confining materials above the source aquifer to contamination from nitrate and various pesticides. Recent studies in Wisconsin have documented the occurrence of viruses in untreated groundwater, even in wells considered to have little vulnerability to contamination from near-surface activities. In addition, sensitive methods have become available for analyses of pharmaceuticals and pesticides. This study represents the first comprehensive examination of contaminants of emerging concern in Iowa’s groundwater conducted to date, and one of the first conducted in the United States. Raw groundwater samples were collected from 66 public supply wells during the spring of 2013, when the state was recovering from drought conditions. Samples were analyzed for 206 chemical and biological parameters; including 20 general water-quality parameters and major ions, 19 metals, 5 nutrients, 10 virus groups, 3 species of pathogenic bacteria, 5 microbial indicators, 108 pharmaceuticals, 35 pesticides and pesticide degradates, and tritium. The wells chosen for this study represent a diverse range of ages, depths, confining material thicknesses, pumping rates, and land use settings. The most commonly detected contaminant group was pesticide compounds, which were present in 41% of the samples. As many as 6 pesticide compounds were found together in a sample, most of which were chloroacetanilide degradates. While none of the measured concentrations of pesticide compounds exceeded current benchmark levels, several of these compounds are listed on the U.S. Environmental Protection Agency’s Contaminant Candidate List and could be subject to drinking water standards in the future. Despite heavy use in the past decade, glyphosate was not detected, and its metabolite, aminomethylphosphonic acid, was only detected in two of 60 wells tested (3%) at the detection limit of 0.02 μg/L. Pharmaceutical compounds were detected in 35% of 63 samples. Of the 14 pharmaceuticals detected, six had reported concentrations above the method reporting limit, with the maximum reported concentration of 826 ng/L for acetaminophen. Diphenhydramine was the only pharmaceutical to have two detections above the reporting limit, at 24.5 and 145 ng/L. Eight pharmaceuticals had confirmed detections at concentrations below the method reporting limit. Caffeine was the most frequently detected pharmaceutical compound (25%), followed by the caffeine metabolite, 1,7- dimethylxanthine (16%). Microorganisms were detected in 21% of the wells using quantitative polymerase chain reaction methodologies. The most frequently detected microorganism was the pepper mild mottle virus (PMMV), a plant pathogen found in human waste. PMMV was detected in 17% of samples at concentrations ranging from 0.4 to 6.38 gene copies per liter. GII norovirus, human polyomavirus, bovine polyomavirus, and Campylobacter were also detected, while adenovirus, enterovirus, GI norovirus, swine hepatitis E, Salmonella, and enterohemmorhagic E. coli were not detected. No correlations were found between viruses or pathogenic bacteria and microbial indicators. Wells with less than 50 feet (15 meters) of confining material were shown to have greater incidence of surface-related contaminants; however, significant relationships (p<0.05) between confining layer thickness and contaminants were only found for nitrate and herbicides.

Iowa↗

USGS2014

Riverbank filtration potential of pharmaceuticals in a wastewater-impacted stream

Pharmaceutical contamination of shallow groundwater is a substantial concern in effluent-dominated streams, due to high aqueous mobility, designed bioactivity, and effluent-driven hydraulic gradients. In October and December 2012, effluent contributed approximately 99% and 71%, respectively, to downstream flow in Fourmile Creek, Iowa, USA. Strong hydrologic connectivity was observed between surface-water and shallow-groundwater. Carbamazepine, sulfamethoxazole, and immunologically-related compounds were detected in groundwater at greater than 0.02 μg L −1 at distances up to 6 m from the stream bank. Direct aqueous-injection HPLC-MS/MS revealed 43% and 55% of 110 total pharmaceutical analytes in surface-water samples in October and December, respectively, with 16% and 6%, respectively, detected in groundwater approximately 20 m from the stream bank. The results demonstrate the importance of effluent discharge as a driver of local hydrologic conditions in an effluent-impacted stream and thus as a fundamental control on surface-water to groundwater transport of effluent-derived pharmaceutical contaminants.

Iowa↗

USGS2014

Mycotoxins: diffuse and point source contributions of natural contaminants of emerging concern to streams

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 detections of mycotoxins were nearly ubiquitous during this study even though the basin size spanned four orders of magnitude. At least one mycotoxin was detected in 94% of the 116 samples collected. Deoxynivalenol was the most frequently detected mycotoxin (77%), followed by nivalenol (59%), beauvericin (43%), zearalenone (26%), β-zearalenol (20%), 3-acetyl-deoxynivalenol (16%), α-zearalenol (10%), diacetoxyscirpenol (5%), and verrucarin A (1%). In addition, one or more of the three known estrogenic compounds (i.e. zearalenone, α-zearalenol, and β-zearalenol) were detected in 43% of the samples, with maximum concentrations substantially higher than observed in previous research. While concentrations were generally low (i.e. < 50 ng/L) during this study, concentrations exceeding 1000 ng/L were measured during spring snowmelt conditions in agricultural settings and in wastewater treatment plant effluent. Results of this study suggest that both diffuse (e.g. release from infected plants and manure applications from exposed livestock) and point (e.g. wastewater treatment plants and food processing plants) sources are important environmental pathways for mycotoxin transport to streams. The ecotoxicological impacts from the long-term, low-level exposures to mycotoxins alone or in combination with complex chemical mixtures are unknown

Science of the Total Environment↗

USGS2013

Chemical contaminants in water and sediment near fish nesting sites in the Potomac River basin: determining potential exposures to smallmouth bass (Micropterus dolomieu)

The Potomac River basin is an area where a high prevalence of abnormalities such as testicular oocytes (TO), skin lesions, and mortality has been observed in smallmouth bass (SMB, Micropterus dolomieu). Previous research documented a variety of chemicals in regional streams, implicating chemical exposure as one plausible explanation for these biological effects. Six stream sites in the Potomac basin (and one out-of-basin reference site) were sampled to provide an assessment of chemicals in these streams. Potential early life-stage exposure to chemicals detected was assessed by collecting samples in and around SMB nesting areas. Target chemicals included those known to be associated with important agricultural and municipal wastewater sources in the Potomac basin. The prevalence and severity of TO in SMB were also measured to determine potential relations between chemistry and biological effects. A total of 39 chemicals were detected at least once in the discrete-water samples, with atrazine, caffeine, deethylatrazine, simazine, and iso-chlorotetracycline being most frequently detected. Of the most frequently detected chemicals, only caffeine was detected in water from the reference site. No biogenic hormones/sterols were detected in the discrete-water samples. In contrast, 100 chemicals (including six biogenic hormones/sterols) were found in a least one passive-water sample, with 25 being detected at all such samples. In addition, 46 chemicals (including seven biogenic hormones/sterols) were found in the bed-sediment samples, with caffeine, cholesterol, indole, para-cresol, and sitosterol detected in all such samples. The number of herbicides detected in discrete-water samples per site had a significant positive relation to TO rank (a nonparametric indicator of TO), with significant positive relations between TO rank and atrazine concentrations in discrete-water samples and to total hormone/sterol concentration in bed-sediment samples. Such significant correlations do not necessarily imply causation, as these chemical compositions and concentrations likely do not adequately reflect total SMB exposure history, particularly during critical life stages.

Potomac River Basin↗

USGS2010

Phytoestrogens and mycotoxins in Iowa streams: An examination of underinvestigated compounds in agricultural basins

This study provides the first broad-scale investigation on the spatial and temporal occurrence of phytoestrogens and mycotoxins in streams in the United States. Fifteen stream sites across Iowa were sampled five times throughout the 2008 growing season to capture a range of climatic and crop-growth conditions. Basin size upstream from sampling sites ranged from 7 km 2 to >836,000 km 2 Atrazine (herbicide) also was measured in all samples as a frame-of-reference agriculturally derived contaminant. Target compounds were frequently detected in stream samples: atrazine (100%), formononetin (80%), equol (45%), deoxynivalenol (43%), daidzein (32%), biochanin A (23%), zearalenone (13%), and genistein (11%). The nearly ubiquitous detection of formononetin (isoflavone) suggests a widespread agricultural source, as one would expect with the intense row crop and livestock production present across Iowa. Conversely, the less spatially widespread detections of deoxynivalenol (mycotoxin) suggest a more variable source due to the required combination of proper host and proper temperature and moisture conditions necessary to promote Fusarium spp. infections. Although atrazine concentrations commonly exceeded 100 ng L -1 (42/75 measurements), only deoxynivalenol (6/56 measurements) had concentrations that occasionally exceeded this level. Temporal patterns in concentrations varied substantially between atrazine, formononetin, and deoxynivalenol, as one would expect for contaminants with different source inputs and processes of formation and degradation. The greatest phytoestrogen and mycotoxin concentrations were observed during spring snowmelt conditions. Phytoestrogens and mycotoxins were detected at all sampling sites regardless of basin size. The ecotoxicological effects from long-term, low-level exposures to phytoestrogens and mycotoxins or complex chemicals mixtures including these compounds that commonly take place in surface water are poorly understood and have yet to be systematically investigated in environmental studies.

Iowa↗