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At least 415 records · Page 23Linked to original sources

Use of Numerical Models to Simulate Transport of Sewage-Derived Nitrate in a Coastal Aquifer, Central and Western Cape Cod, Massachusetts

The unconsolidated glacial sediments underlying Cape Cod, Massachusetts compose a regional aquifer system that is used both as a source of drinking water and as a disposal site for wastewater; in addition, the discharge of clean ground water from the aquifer system is needed for the maintenance of freshwater and marine ecosystems throughout the region. Because these uses of the aquifer conflict with one another in many areas of the Cape, local and regional planners have begun to develop sustainable wastewater plans that will facilitate the disposal of wastewater while protecting water supplies and improving the health of aquatic ecosystems. To assist local and regional planners in these efforts, the U.S. Geological Survey conducted a 2-year investigation to (1) assist local and regional planners in the evaluation of potential wastewater scenarios, (2) use results and interpretation from these analyses to develop hydrologic concepts transferable throughout the region, and (3) establish and test methods that would be of use in future evaluations. Wastewater-disposal scenarios need to be evaluated in the context of the regional ground-water-flow system. For a given rate of disposal, wastewater from sites at or near a regional ground-water divide is transported in a wider arc of flow directions, flows deeper in the system, and contaminates a larger part of the aquifer than does wastewater discharged from sites farther from the divide. Also, traveltimes of wastewater from sites near a ground-water divide to receptors are longer (as much as several hundred years) than traveltimes from sites farther from the divide. Thus, wastewater disposal at or near a divide will affect a larger part of the aquifer and likely contribute wastewater to more receptors than wastewater disposal farther from a divide; however, longer traveltimes could allow for more attenuation of wastewater-derived nitrate from those sites. Ground-water-flow models and particle tracking can be used to identify advective-transport patterns downgradient from wastewater-disposal sites and estimate traveltimes; however, these tools cannot predict the distribution of mass or concentrations of wastewater constituents, such as nitrate, in the aquifer. Flow-based particle-tracking analyses can be used to estimate mass-loading rates and time-varying concentrations at wells and ecological receptors by the accounting of mass-weighted particles discharging into the receptor of interest. This method requires no additional development beyond the flow model; however, post-modeling analyses are required. In addition, the method is based on the assumption that no mass is lost during transport, an assumption that likely is not valid in many systems. Solute-transport models simulate the subsurface transport of nitrate through the aquifer and predict the distribution of the mass of a solute in the aquifer at different transport times. This method does require additional model development beyond the flow model, but can predict timevarying concentrations at receptors. Estimates of mass-loading rates require minimal post-modeling analyses. Time-varying concentrations and mass-loading rates calculated for wells in eastern Barnstable by the two methods generally were in reasonable agreement. Inherent in the flow-based particle-tracking method is the assumption that mass is conserved along a given flow line and that there is no spreading of mass in the aquifer. Although the solute-transport models also incorporate a system-wide conservation of mass, these models allow for a spreading of mass in the aquifer, and mass is not conserved along a given flow line. As a result, estimates of concentrations and mass loading rates generally were higher in particle-tracking analyses than in solute-transport simulations. Results from the two types of simulations agreed best for wells that receive large amounts of wastewater with short traveltimes (less than 10 years) because insufficient transport

Scientific Investigations Report↗

Aquifer Tests and Characterization of Transmissivity, Ada-Vamoosa Aquifer on the Osage Reservation, Osage County, Oklahoma, 2006

The Ada-Vamoosa aquifer of northeastern Oklahoma is a sedimentary bedrock aquifer of Pennsylvanian age that crops out over 800 square miles of the Osage Reservation. The Osage Nation needed additional information regarding the production potential of the aquifer to aid them in future development planning. To address this need, the U.S. Geological Survey, in cooperation with the Osage Nation, conducted a study of aquifer properties in the Ada-Vamoosa aquifer. This report presents the results of the aquifer tests from 20 wells in the Ada-Vamoosa aquifer and one well in a minor aquifer east of the Ada-Vamoosa outcrop on the Osage Reservation. Well information for 17 of the 21 wells in this report was obtained from the Indian Health Service. Data collected by the U.S. Geological Survey during this investigation are pumping well data from four domestic wells collected during the summer of 2006. Transmissivity values were calculated from well pumping data or were estimated from specific capacity values depending on the reliability of the data. The estimated transmissivity values are 1.1 to 4.3 times greater than the calculated transmissivity values. The calculated and estimated transmissivity values range from 5 to 1,000 feet squared per day.

Scientific Investigations Report↗

Peracute sodium toxicity in free-ranging black-bellied whistling duck ducklings

From 23 to 25 July 2002, 98–103 newly hatched black-bellied whistling ducks ( Dendrocygna autumnalis ) were observed alive at an inland saline lake (La Sal Vieja) in Willacy County, Texas (USA). Seventy-one (71%) died after showing signs indicative of sodium toxicity within 5 hr of entering the water; some died within minutes. Six carcasses were sent to the United States Geological Survey, National Wildlife Health Center (Madison, Wisconsin, USA) for analysis, and brain sodium levels of all ducklings were above 2,000 parts per million wet weight. More black-bellied whistling duck ducklings are likely to have been affected, but they were not observed after hatching.

Texas↗

Pharmaceutical pollution of the world’s rivers

Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world’s rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals.

Proceedings of the National Academy of Sciences↗

Water quality on the Prairie Band Potawatomi Reservation, northeastern Kansas, June 1996 through August 2006

This report describes surface- and ground-water-quality data collected on the Prairie Band Potawatomi Reservation in northeastern Kansas from November 2003 through August 2006 (hereinafter referred to as the "current study period"). Data from this study period are compared to results from June 1996 through August 2003, which are published in previous reports as part of a multiyear cooperative study with the Prairie Band Potawatomi Nation. Surface and ground water are valuable resources to the Prairie Band Potawatomi Nation as tribal members currently (2007) use area streams to fulfill subsistence hunting and fishing needs and because ground water potentially could support expanding commercial enterprise and development. Surface-water-quality samples collected from November 2003 through August 2006 were analyzed for physical properties, dissolved solids, major ions, nutrients, trace elements, pesticides, fecal-indicator bacteria, suspended-sediment concentration, and total suspended solids. Ground-water samples were analyzed for physical properties, dissolved solids, major ions, nutrients, trace elements, pesticides, and fecal-indicator bacteria. Chemical oxygen demand and volatile organic compounds were analyzed in all three samples from one monitoring well located near a construction and demolition landfill on the reservation, and in one sample from another well in the Soldier Creek drainage basin. Previous reports published as a part of this ongoing study identified total phosphorus, triazine herbicides, and fecal coliform bacteria as exceeding their respective water-quality criteria in surface water on the reservation. Previous ground-water assessments identified occasional sample concentrations of dissolved solids, sodium, sulfate, boron, iron, and manganese as exceeding their respective water-quality criteria. Fifty-six percent of the 55 surface-water samples collected during the current study period and analyzed for total phosphorus exceeded the goal of 0.1 mg/L (milligram per liter) established by the U.S. Environmental Protection Agency (USEPA) to limit cultural eutrophication in flowing water. Concentrations of dissolved solids frequently exceeded the USEPA Secondary Drinking-Water Regulation (SDWR) of 500 mg/L in samples from two sites. Concentrations of sodium exceeded the Drinking-Water Advisory of 20 mg/L set by USEPA in almost 50 percent of the surface-water samples. All four samples analyzed for atrazine concentrations showed some concentration of the pesticide, but none exceeded the Maximum Contaminant Level (MCL) established for drinking water by USEPA of 3.0 µg/L (micrograms per liter) as an annual average. A triazine herbicide screen was used on 55 surface-water samples, and triazine compounds were frequently detected. Triazine herbicides and their degradates are listed on the USEPA Contaminant Candidate List. In 41 percent of surface-water samples, densities of Escherichia coli ( E. coli ) bacteria exceeded the primary contact, single-sample maximum in public-access bodies of water (1,198 colonies per 100 milliliters of water for samples collected between April 1 and October 31) set by the Kansas Department of Health and Environment (KDHE). Nitrite plus nitrate concentrations in all three water samples from 1 of 10 monitoring wells exceeded the MCL of 10 mg/L established by USEPA for drinking water. Arsenic concentrations in all three samples from one well exceeded the proposed MCL of 10 µg/L established by USEPA for drinking water. Boron also exceeded the drinking-water advisory in three samples from one well, and iron concentrations were higher than the SDWR in water from four wells. There was some detection of pesticides in ground-water samples from three of the wells, and one detection of the volatile organic compound diethyl ether in one well. Concentrations of dissolved solids exceeded the SDWR in 20 percent of ground-water samples collected during the current study period, and concentrations of sulfate and chloride exceeded their respective SDWR in 10 percent of the ground-water samples. Concentrations exceeded the Drinking-Water Advisory Level set by USEPA for sodium in 50 percent of the ground-water samples. Results from the current study period remained similar to results from previous study periods. The median triazine herbicide concentration (triazine screen by ELISA) for the current study period decreased slightly compared to past study periods. In the event that ground water on the reservation is to be used as a drinking-water source, additional treatment may be necessary to remove excess dissolved solids, sulfate, sodium, and chloride.

Kansas↗

Investigation of fish communities in natural channel sections of the Mohawk River, New York

Little is known about the natural resources in the natural channel sections of the Mohawk River between Rome and Frankfort, New York, where the river channel runs separately from and parallel to the Erie Canal. This river section runs through multiple locations that are listed as active remediation sites under New York’s Inactive Hazardous Waste Disposal Site Program and has negligible public or commercial access. As a result, there is minimal recreational usage of this river section, and efforts to conduct biological sampling have been limited. To better understand the composition of fish communities and contaminant concentrations in the natural channel of the Mohawk River, the U.S. Geological Survey, in cooperation with the New York State Department of Environmental Conservation, sampled resident fish in the 34-kilometer section from the mouth of Oriskany Creek downstream to Frankfort. Fish communities were sampled using boat electrofishing during 2021, 2023, and 2024 across multiple reaches within this section. These data were used to estimate species richness (number of species), relative abundance and biomass (catch rates), population size structure (distribution of lengths), and fish condition (a proxy for health). Some gamefish specimens were also analyzed to determine contaminant concentrations in fish tissue. A total of 1,531 individual fish and 38 fish species were captured across all surveys. Seventeen of the 38 (45 percent) species were classified as native to the Mohawk River watershed, whereas 21 of the 38 (55 percent) species were classified as nonnative. Some popular gamefish species such as largemouth bass ( Micropterus salmoides ) and smallmouth bass ( Micropterus dolomieu ) were abundant in most reaches, whereas others such as walleye ( Sander vitreus ) and northern pike ( Esox lucius ) were found sporadically. Only one round goby ( Neogobius melanostomus ) was captured, indicating that this high-profile invasive species remains uncommon in this habitat. A backwater reach had the greatest relative abundance and condition of many species. This indicates connected lentic habitats such as oxbows and backwaters may be important nursery and refuge areas in the aquatic ecosystem. Polychlorinated biphenyl (PCB) concentrations in fish tissue were highly elevated relative to the New York State Department of Health (NYSDOH) fish consumption “don’t eat” advisory guideline. Some specimens exceeded the guideline by an order of magnitude or more, particularly those from a localized area downstream from the Utica Harbor Dam. Concentrations of perfluorooctanesulfonic acid (PFOS) often approached the NYSDOH “don’t eat” consumption guideline but only one sample exceeded the guideline. Concentrations of other contaminants such as mercury and pesticides were consistently measured at less than the “don’t eat” consumption guidelines. These data indicate PCBs remain the primary contaminant of concern in the natural channel of the Mohawk River and are readily bioaccumulating in aquatic organisms despite prior remediation measures. Taken together, the findings in this report are intended to inform future decisions related to fisheries management, public access, recreational usage, and fish consumption advisories.

New York↗

Evaluation of four structural best management practices for highway runoff in Beaufort and Colleton Counties, South Carolina, 2005–2006

From 2005 to 2006, the U.S. Geological Survey worked cooperatively with the South Carolina Department of Transportation in Beaufort and Colleton Counties, South Carolina, to assess the performance of four different structural devices that served as best management practices (BMPs). These structural devices were installed to mitigate the effects of stormwater runoff on waterways near State roads. The South Carolina Department of Transportation is required to address the quality of stormwater runoff from State-maintained roadways as part of the National Pollutant Discharge Elimination System stormwater program mandated in the Clean Water Act. The performance assessment of the four structural best management practices was based on stormflow measurements and chemical analyses of stormwater-quality samples collected during a 20-month period from March 2005 through October 2006, which represented a range of seasons and rainfall intensities. A total of 49 sample sets that included stormwater from the inlet and outlet of each of the four structural devices were collected as flow-weighted composites to provide event-mean concentrations of suspended sediment, nutrients, and trace metals. In addition, each set included grab samples that were collected to provide the first flush concentrations of oil and grease and fecal-indicator bacteria. A tiered statistical approach was used in the data analysis. Performances of the four structural BMPs were assessed individually based on how well the BMPs were able to reduce the selected constituents. Descriptive statistics and nonparametric Wilcoxon signed rank tests were applied to event-mean concentrations and loads in the water entering the inlet and in the water leaving the outlet of each BMP for each constituent to identify if significant reductions occurred. If significant reductions occurred, the BMP was considered efficient at reducing the constituent. To quantify efficiency, a simplistic approach was applied to compute mean and geometric mean efficiency ratios for the significantly reduced constituents in each BMP. Each BMP performance was ranked based on its computed efficiency ratios, however, the computed efficiency ratios were not sufficient to determine if statistical differences occurred among the performances of the four BMPs. Consequently, a more complex approach was used to apply statistical comparison tests to reduction percentages computed for individual storms (a modified removal efficiency of individual storm-load approach) to determine if differences in event-mean concentrations, loads, and reduction percentages for significantly reduced constituents occurred among the four structural BMPs. Overall, the four BMPs were efficient in reducing suspended-sediment event-mean concentrations and loads in the stormwater entering the inlets of the BMPs to significantly lower event-mean concentrations before discharging the stormwater from the outlets. The cumulative suspended-sediment event-mean load in stormwater entering the BMPs from the storms sampled during the data-collection period was 1,026 kilograms (1.13 tons). The BMPs removed a cumulative suspended-sediment load of 558 kilograms (0.62 ton). The BMPs tended to preferentially trap the sand-size fraction of the sediment, thereby releasing a greater percentage of fine-grained (silt and clay) sediment in the water discharging from the outlet. The preferential trapping of fine-grained sediment by the BMPs could explain, at least in part, why the BMPs were not successful at significantly reducing these constituents. In general, the four BMPs were not successful at significantly reducing fecal bacteria, nutrients, and total organic carbon (including associated properties of biochemical oxygen demand and chemical oxygen demand). Three of the four BMPs significantly lowered oil and grease concentrations before the stormwater discharged from the outlet. Additionally, only one BMP was effective at reducing all total and particulate trace-metal event-mean concentrations and particulate trace-metal event-mean loads in stormwater entering the inlet. With respect to trace-metal event-mean concentrations, however, minimal or no improvement in outlet water quality was observed for the four BMPs, and the majority of the outlet concentrations were above the established acute and chronic aquatic-life criteria by the South Carolina Department of Health and Environmental Control. No statistical differences among the removal-efficiency of the four BMPs were determined for suspended-sediment event-mean concentrations, total suspended solids event-mean concentrations, or oil and grease concentrations. These statistical findings indicated that differences among the mean efficiency ratios were not significant among the BMPs for these properties. Additionally, one BMP generally had statistically greater removal efficiency for total and particulate cadmium, copper, lead, and zinc than one or more of the other three BMPs. Statistical correlation tests were unable to identify a single major factor that would explain the high variability in inlet and outlet water concentrations and in removal efficiencies estimated by reduction percentage. Highly variable inlet and outlet concentrations for each BMP that produced highly variable reduction percentages were probably the result of multiple interacting factors, particularly rainfall intensity, the amount of rainfall between sampling events, traffic density, and the period of time since the last maintenance (clean out) of the BMP.

South Carolina↗

Human interactions with sirenians (manatees and dugongs)

There are three extant sirenian species of the Trichechidae family and one living Dugongidae family member. Given their close ties to coastal and often urbanized habitats, sirenians are exposed to many types of anthropogenic activities that result in challenges to their well-being, poor health, and even death. In the wild, they are exposed to direct and indirect local pressures as well as subject to large-scale stressors such as global climate change acting on regions or entire genetic stocks. In captivity, they are subject to husbandry and management practices based on our collective knowledge, or in some cases lack thereof, of their needs and welfare. It is therefore reasonable to consider that their current imperiled status is very closely linked to our actions. In this chapter, we identify and define human interactions that may impact dugongs and manatees, including hunting, fisheries, boat interactions, negative interactions with man-made structures, disease and contaminants, and global climate change. We examine techniques used to investigate these impacts and the influence of sirenian biology and of changing human behaviors on potential outcomes. We examine how this differs for dugongs and manatees in the wild and for those held in captivity. Finally, we provide possible mitigation strategies and ways to assess the efforts we are making to improve the welfare of individuals and to conserve these species. This chapter identifies how the welfare of these species is intrinsically linked to the human interactions these animals experience, and how the nature of these interactions has changed with societal shifts. We proffer suggested ways to minimize negative impacts. Current knowledge should be used to minimize negative human interactions and impacts, to promote positive impacts, and to protect these animals for the future.

Book chapter↗

Impact of West Nile virus and other mortality factors on American white pelicans at breeding colonies in the northern plains of North America

American white pelicans (Pelecanus erythrorhynchos) are colonial-nesting birds and their breeding sites are concentrated in a few small areas, making this species especially vulnerable to factors that can influence productivity, such as disease, disturbance, predation, weather events and loss of nesting habitat. Nearly half of the American white pelican population breeds at four colonies in the northern plains: Chase Lake National Wildlife Refuge (NWR) in North Dakota, Bitter Lake (Waubay NWR) in South Dakota, Medicine Lake NWR in Montana, and Marsh Lake in Minnesota. Thus, sustained productivity at these colonies is crucial to the health of the entire species. During the latter half of the 2002 and 2003 breeding seasons, unusually high mortality of pelican chicks was observed at these colonies. West Nile virus (WNv) was identified as one source of these losses. In 2004-2007 we monitored three major colonies in the northern plains to assess mortality of chicks during the late breeding season. We documented severe weather events, disturbance, and WNv as factors contributing to chick mortality. Before WNv arrived in the region in 2002, chick mortality after mid-July was ???4%, and then jumped to as high as 44% in the years since WNv arrived. WNv kills older chicks that are no longer vulnerable to other common mortality factors (e.g., severe weather, gull predation) and typically would have survived to fledge; thus WNv appears to be an additive mortality factor. Persistence of lower productivity at American white pelican colonies in the northern plains might reduce the adult breeding population of this species in the region.

Montana, North Dakota, South Dakota↗

Arsenic in ground water in Genesee County, Michigan

Previous studies of ground-water resources in Michigan by the Michigan Department of Community Health (MDCH), the Michigan Department of Environmental Quality (MDEQ), and the U.S. Geological Survey (USGS) indicate that in several counties in the southeastern part of the State the concentrations of arsenic in ground water may exceed the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 50 micrograms per liter [µg/L]. This MCL was established in 1986. The Safe Drinking Water Act, as amended in 1996, requires USEPA to revise this standard in 2000. In June 2000, the USEPA proposed a revised MCL of 5 µg/L. In 1996, the USGS, in cooperation with the MDEQ and the Health Departments of Genesee, Huron, Lapeer, Livingston, Oakland, Sanilac, Shiawassee, Tuscola and Washtenaw counties, began a study of the factors controlling arsenic occurrence and concentrations in ground water in southeastern Michigan. This study is one of four USGS Drinking Water Initiative projects throughout the United States.

Michigan↗

Arsenic in ground water in Livingston County, Michigan

Previous studies of ground-water resources in Michigan by the Michigan Department of Community Health (MDCH), the Michigan Department of Environmental Quality (MDEQ), and the U.S. Geological Survey (USGS) indicate that in several counties in the southeastern part of the State the concentrations of arsenic in ground water may exceed the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 50 micrograms per liter [µg/L]. This MCL was established in 1986. The Safe Drinking Water Act, as amended in 1996, requires USEPA to revise this standard in 2000. In June 2000, the USEPA proposed a revised MCL of 5 µg/L. In 1996, the USGS, in cooperation with the MDEQ and the Health Departments of Genesee, Huron, Lapeer, Livingston, Oakland, Sanilac, Shiawassee, Tuscola and Washtenaw counties, began a study of the factors controlling arsenic occurrence and concentrations in ground water in southeastern Michigan. This study is one of four USGS Drinking Water Initiative projects throughout the United States.

Michigan↗

Arsenic in ground water in Shiawassee County, Michigan

Previous studies of ground-water resources in Michigan by the Michigan Department of Community Health (MDCH), the Michigan Department of Environmental Quality (MDEQ), and the U.S. Geological Survey (USGS) indicate that in several counties in the southeastern part of the State the concentrations of arsenic in ground water may exceed the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 50 micrograms per liter [µg/L]. This MCL was established in 1986. The Safe Drinking Water Act, as amended in 1996, requires USEPA to revise this standard in 2000. In June 2000, the USEPA proposed a revised MCL of 5 µg/L. In 1996, the USGS, in cooperation with the MDEQ and the Health Departments of Genesee, Huron, Lapeer, Livingston, Oakland, Sanilac, Shiawassee, Tuscola and Washtenaw counties, began a study of the factors controlling arsenic occurrence and concentrations in ground water in southeastern Michigan. This study is one of four USGS Drinking Water Initiative projects throughout the United States.

Michigan↗

Arsenic in ground water in Sanilac County, Michigan

Previous studies of ground-water resources in Michigan by the Michigan Department of Community Health (MDCH), the Michigan Department of Environmental Quality (MDEQ), and the U.S. Geological Survey (USGS) indicate that in several counties in the southeastern part of the State the concentrations of arsenic in ground water may exceed the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 50 micrograms per liter [µg/L]. This MCL was established in 1986. The Safe Drinking Water Act, as amended in 1996, requires USEPA to revise this standard in 2000. In June 2000, the USEPA proposed a revised MCL of 5 µg/L. In 1996, the USGS, in cooperation with the MDEQ and the Health Departments of Genesee, Huron, Lapeer, Livingston, Oakland, Sanilac, Shiawassee, Tuscola and Washtenaw counties, began a study of the factors controlling arsenic occurrence and concentrations in ground water in southeastern Michigan. This study is one of four USGS Drinking Water Initiative projects throughout the United States.

Michigan↗

Arsenic in ground water in Tuscola County, Michigan

Previous studies of ground-water resources in Michigan by the Michigan Department of Community Health (MDCH), the Michigan Department of Environmental Quality (MDEQ), and the U.S. Geological Survey (USGS) indicate that in several counties in the southeastern part of the State the concentrations of arsenic in ground water may exceed the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 50 micrograms per liter [µg/L]. This MCL was established in 1986. The Safe Drinking Water Act, as amended in 1996, requires USEPA to revise this standard in 2000. In June 2000, the USEPA proposed a revised MCL of 5 µg/L. In 1996, the USGS, in cooperation with the MDEQ and the Health Departments of Genesee, Huron, Lapeer, Livingston, Oakland, Sanilac, Shiawassee, Tuscola and Washtenaw counties, began a study of the factors controlling arsenic occurrence and concentrations in ground water in southeastern Michigan. This study is one of four USGS Drinking Water Initiative projects throughout the United States.

Michigan↗

Arsenic in ground water in Washtenaw County, Michigan

Previous studies of ground-water resources in Michigan by the Michigan Department of Community Health (MDCH), the Michigan Department of Environmental Quality (MDEQ), and the U.S. Geological Survey (USGS) indicate that in several counties in the southeastern part of the State the concentrations of arsenic in ground water may exceed the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 50 micrograms per liter [µg/L]. This MCL was established in 1986. The Safe Drinking Water Act, as amended in 1996, requires USEPA to revise this standard in 2000. In June 2000, the USEPA proposed a revised MCL of 5 µg/L. In 1996, the USGS, in cooperation with the MDEQ and the Health Departments of Genesee, Huron, Lapeer, Livingston, Oakland, Sanilac, Shiawassee, Tuscola and Washtenaw counties, began a study of the factors controlling arsenic occurrence and concentrations in ground water in southeastern Michigan. This study is one of four USGS Drinking Water Initiative projects throughout the United States.

Michigan↗

On-site evaluation of the suitability of a wetted instream habitat in the Middle Rio Grande, New Mexico, for the Rio Grande silvery minnow (Hybognathus amarus)

Two in-situ exposure studies were conducted with the federally-listed endangered Rio Grande silvery minnow (Hybognathus amarus). One-year-old adults were exposed in cages deployed at three sites in the Middle Rio Grande, N. Mex., for 4 days to assess survival and for 26 days to evaluate survival, growth, overall health, and whole-body elemental composition. The test sites were located on the Pueblo of Isleta in the (1) main channel of the Middle Rio Grande, (2) 240-Wasteway irrigation return drain, and (3) wetted instream habitat created below the outfall of the 240-Wasteway irrigation return drain. During the cage exposures, temperature, dissolved oxygen, pH, conductivity, and turbidity were monitored continuously (15-minute intervals) and common constituents, nutrients, carbons, metals, and pesticides were measured at discrete intervals. In both studies, there were statistical differences in several water-quality parameters among sites; and except for turbidity, these differences were small and were not considered to be biologically significant. The cages used in the 4-day exposure study were ineffective at preventing access to the fish by predators, and survival was highly variable (20 percent to 90 percent) across sites. In the 26-day chronic exposure study, weight and condition factor of caged-exposed fish at all sites were significantly lower than those at test initiation. After 26 days of exposure, there were no significant differences in survival, total length, weight, or condition factor of fish across sites, but absolute weight loss and relative reduction in condition factor were significantly greater in fish at the wetted instream habitat site compared to those at the Middle Rio Grande site. There were no statistical differences in health assessment indices, mesenteric fat indices, or prevalence of abnormalities in cage-exposed fish among sites. Cage-exposed fish had higher health assessment indices and prevalence of fin anomalies and a lower mesenteric fat indices compared to pre-exposed fish. Prevalence of macrophage aggregates in the kidney, liver, and spleen of caged-exposed fish was similar across sites and also was similar to those in pre-exposed fish. Absolute and relative weight loss and relative reduced condition factors were inversely correlated with water depth in the cages, which were the lowest at the WIH site.

New Mexico↗

Baseline assessment of groundwater quality in Pike County, Pennsylvania, 2015

The Devonian-age Marcellus Shale and the Ordovician-age Utica Shale, which have the potential for natural gas development, underlie Pike County and neighboring counties in northeastern Pennsylvania. In 2015, the U.S. Geological Survey, in cooperation with the Pike County Conservation District, conducted a study that expanded on a previous more limited 2012 study to assess baseline shallow groundwater quality in bedrock aquifers in Pike County prior to possible extensive shale-gas development. Seventy-nine water wells ranging in depths from 80 to 610 feet were sampled during June through September 2015 to provide data on the presence of methane and other aspects of existing groundwater quality in the various bedrock geologic units throughout the county, including concentrations of inorganic constituents commonly present at low values in shallow, fresh groundwater but elevated in brines associated with fluids extracted from geologic formations during shale-gas development. All groundwater samples collected in 2015 were analyzed for bacteria, dissolved and total major ions, nutrients, selected dissolved and total inorganic trace constituents (including metals and other elements), radon-222, gross alpha- and gross beta-particle activity, dissolved gases (methane, ethane, and propane), and, if sufficient methane was present, the isotopic composition of methane. Additionally, samples from 20 wells distributed throughout the county were analyzed for selected man-made volatile organic compounds, and samples from 13 wells where waters had detectable gross alpha activity were analyzed for radium-226 on the basis of relatively elevated gross alpha-particle activity. Results of the 2015 study show that groundwater quality generally met most drinking-water standards for constituents and properties included in analyses, but groundwater samples from some wells had one or more constituents or properties, including arsenic, iron, manganese, pH, bacteria, sodium, chloride, sulfate, total dissolved solids, and radon-222, that did not meet (commonly termed failed or exceeded) primary or secondary maximum contaminant levels (MCLs) or Health Advisories (HA) for drinking water. Except for iron, dissolved and total concentrations of major ions and most trace constituents generally were similar. Only 1 of 79 well-water samples had any constituent that exceeded a MCL, with an arsenic concentration of about 30 micrograms per liter (µg/L) that was higher than the MCL of 10 µg/L. However, total arsenic concentrations were higher than the HA of 2 µg/L in samples from another 12 of 79 wells (about 15 percent). Secondary maximum contaminant levels (SMCLs) were exceeded most frequently by pH and concentrations of iron and manganese. The pH was outside of the SMCL range of 6.5–8.5 in samples from 24 of 79 wells (30 percent), ranging from 5.5 to 9.2; more samples had pH values less than 6.5 than had pH values greater than 8.5. Total iron concentrations typically were much greater than dissolved iron concentrations, indicating substantial presence of iron in particulate phase, and exceeded the SMCL of 300 µg/L more often [35 of 79 samples (44 percent)] than dissolved iron concentrations [samples from 8 of 79 wells (10 percent)]. Total manganese concentrations exceeded the SMCL of 50 µg/L in samples from 31 of 79 wells (39 percent) and the HA of 300 µg/L in samples from 13 of 79 wells (about 16 percent). A few (1–2) samples had concentrations of sodium, chloride, sulfate, or TDS higher than the SMCLs of 60, 250, 250, and 500 mg/L, respectively. However, dissolved sodium concentrations were higher than the HA of 20 mg/L in samples from 15 of 79 wells (nearly 20 percent). Total coliform bacteria were detected in samples from 25 of 79 wells (32 percent) but Escherichia coli were not detected in any sample. Radon-222 activities ranged from 11 to 5,100 picocuries per liter (pCi/L), with a median of 1,440 pCi/L, and exceeded the proposed and the alternate proposed drinking-water standards of 300 and 4,000 pCi/L, respectively, in samples from 60 of 79 wells (75 percent) and in samples from 2 of 79 wells (3 percent), respectively. Groundwater samples from all wells were analyzed for dissolved methane by one contract laboratory that determined water from 19 of the 79 wells (24 percent) had concentrations of methane greater than the reporting level of 0.010 milligrams per liter (mg/L) with a maximum methane concentration of 2.5 mg/L. Methane concentrations in 18 replicate samples submitted to a second laboratory for dissolved gas and isotopic analysis generally were higher by as much as a factor of 2.7 from those determined by the first laboratory, indicating potential bias related to combined sampling and analytical methods, and therefore, caution needs to be used when comparing methane results determined by different methods. The isotopic composition of methane in 9 of 10 samples with sufficient dissolved methane (about 0.3 mg/L) for isotopic analysis is consistent with values reported for methane of microbial origin produced through carbon dioxide reduction; an isotopic shift in 1 or 2 samples may indicate subsequent methane oxidation. The low concentrations of ethane relative to methane in these samples further indicate that the methane may be of microbial origin. Groundwater samples with relatively elevated methane concentrations (near or greater than 0.3 mg/L) also had chemical compositions that differed in some respects from groundwater with relatively low methane concentrations (less than 0.3 mg/L) by having higher pH (greater than 8) and higher concentrations of sodium, lithium, boron, fluoride, arsenic, and bromide and chloride/bromide ratios indicative of mixing with a small amount of brine of probable natural occurrence. The spatial distribution of groundwater compositions differs by topographic setting and lithology and generally shows that (1) relatively dilute, slightly acidic, oxygenated, calcium-carbonate type waters tend to occur in the uplands underlain by the undivided Poplar Gap and Packerton members of the Catskill Formation in southwestern Pike County; (2) waters of near neutral pH with the highest amounts of hardness (calcium and magnesium) generally occur in areas of intermediate altitudes underlain by other members of the Catskill Formation; and (3) waters with pH values greater than 8, low oxygen concentrations, and the highest arsenic, sodium, lithium, bromide, and methane concentrations can be present in deep wells in uplands but most frequently occur in stream valleys, especially at low altitudes (less than about 1,200 feet above North American Vertical Datum of 1988) where groundwater may be discharging regionally, such as to the Delaware River in northern and eastern Pike County. Thus, the baseline assessment of groundwater quality in Pike County prior to gas-well development shows that shallow (less than about 1,000 feet deep) groundwater generally meets primary drinking-water standards for inorganic constituents but varies spatially, with methane and some constituents present in high concentrations in brine (and connate waters from gas and oil reservoirs) present at low to moderate concentrations in some parts of Pike County.

Pennsylvania↗

Assessment of rangeland ecosystem conditions in Grand Canyon-Parashant National Monument, Arizona

Sustainability of dryland ecosystems depends on the functionality of soil-vegetation feedbacks that affect ecosystem processes, such as nutrient cycling, water capture and retention, soil erosion and deposition, and plant establishment and reproduction. Useful, common indicators can provide information on soil and site stability, hydrologic function, and biotic integrity. Evaluation of rangeland health thus relies on describing the condition and sustainability of these individual, measurable, and observable indicators that are linked to important ecosystem processes. This report focuses on the ~200,000 acres of the Grand Canyon-Parashant National Monument that is administered by the National Park Service (NPS)—one of the largest NPS units where livestock grazing is a permitted land-use activity. Many ecosystems in the monument are characterized by a low degree of resilience to improper grazing because of low and variable precipitation. The monument is marked by a high degree of environmental heterogeneity, including a large elevation gradient, widely differing precipitation patterns, a diversity of geologic substrates, and unique combinations of plant species. The objective of this report is to (1) increase our understanding of the underlying landscape, soil, and climate setting factors that affect Grand Canyon-Parashant National Monument dryland ecosystem structure and function (also referred to as land potential) and (2) characterize the condition of monument ecosystems in relation to management concepts, such as rangeland health. Data were analyzed by elevation zone using both univariate and multivariate approaches. Survey results document the high level of diversity within the study area, including 15 unique soil taxa and 271 species of plants. We collected three new plant species for Grand Canyon-Parashant National Monument and 17 new species for the NPS portion of the monument. Results also document a strong association between rangeland health indicators and elevation, topographic setting, and soils. Soil factors found to explain important variation across plots include the amount of exposed bedrock, soil rockiness, soil texture (and associated hydrologic properties), and soil depth. We also found that dominant species turnover across elevation may represent species’ differences in adaptation to climates, including Larrea tridentata , Coleogyne ramosissima , and Artemisia spp. Bromus rubens is the most common invasive species of concern recorded in this study, but other common invasive species are Bromus tectorum , Erodium cicutarium , and Schismus arabicus . Correlations between an index of cattle use and indicators of rangeland health suggest that areas with high cattle use have increased bare ground, decreased ground cover, increased frequency of Schismus arabicus , decreased cover of Coleogyne ramosissima and Ephedra spp., and increased cover of Gutierrezia spp. The few strong correlations observed between indicators of vascular plant community cover or abundance and indicators of cattle activity support rangeland assessment and monitoring strategies that do not rely solely on plant-based indicators are needed. This work supports management of dryland ecosystems, including Grand Canyon-Parashant National Monument, using concepts of land potential. We conclude the report with recommendations on improving existing land-potential-based classification systems, associated interpretations, and methods for moving forward with a Grand Canyon-Parashant National Monument rangeland monitoring program.

Arizona↗