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USGS2014

Health status of Largescale Sucker ( Catostomus macrocheilus ) collected along an organic contaminant gradient in the lower Columbia River, Oregon and Washington, USA

The health of Largescale Sucker ( Catostomus macrocheilus ) in the lower Columbia River (USA) was evaluated using morphometric and histopathological approaches, and its association with organic contaminants accumulated in liver was evaluated in males. Fish were sampled from three sites along a contaminant gradient In 2009, body length and mass, condition factor, gonadosomatic index, and hematocrit were measured in males and females; liver and gonad tissue were collected from males for histological analyses; and organ composites were analyzed for contaminant content in males. In 2010, additional data were collected for males and females, including external fish condition assessment, histopathologies of spleen, kidney and gill and, for males, liver contaminant content. Multivariate analysis of variance indicated that biological traits in males, but not females, differed among sites in 2009 and 2010. Discriminant function analysis indicated that site-related differences among male populations were relatively small in 2009, but in 2010, when more variables were analyzed, males differed among sites in regards to kidney, spleen, and liver histopathologies and gill parasites. Kidney tubular hyperplasia, liver and spleen macrophage aggregations, and gill parasites were generally more severe in the downstream sites compared to the reference location. The contaminant content of male livers was also generally higher downstream, and the legacy pesticide hexachlorobenzene and flame retardants BDE-47 and BDE-154 were the primary drivers for site discrimination. However, bivariate correlations between biological variables and liver contaminants retained in the discriminant models failed to reveal associations between the two variable sets. In conclusion, whereas certain non-reproductive biological traits and liver contaminant contents of male Largescale Sucker differed according to an upstream-downstream gradient in the lower Columbia River, results from this study did not reveal the specific environmental factors responsible for the differences in health status among fish populations.

Science of the Total Environment↗

USGS2022

Plague and trace metals in natural systems

All pathogenic organisms are exposed to abiotic influences such as the microclimates and chemical constituents of their environments. Even those pathogens that exist primarily within their hosts or vectors can be influenced directly or indirectly. Yersinia pestis , the flea-borne bacterium causing plague, is influenced by climate and its survival in soil suggests a potentially strong influence of soil chemistry. We summarize a series of controlled studies conducted over four decades in Russia by Dr. Evgeny Rotshild and his colleagues that investigated correlations between trace metals in soils, plants, and insects, and the detection of plague in free-ranging small mammals. Trace metal concentrations in plots where plague was detected were up to 20-fold higher or lower compared to associated control plots, and these differences were >2-fold in 22 of 38 comparisons. The results were statistically supported in eight studies involving seven host species in three families and two orders of small mammals. Plague tended to be positively associated with manganese and cobalt, and the plague association was negative for copper, zinc, and molybdenum. In additional studies, these investigators detected similar connections between pasturellosis and concentrations of some chemical elements. A One Health narrative should recognize that the chemistry of soil and water may facilitate or impede epidemics in humans and epizootics in non-human animals.

International Journal of Environmental Research an↗

USGS2025

Waterfront property owners' shoreline preferences amid salt marsh to mangrove transitions

1. We examined the influence of mangrove encroachment into salt marsh areas along the northern Gulf of Mexico (USA) on waterfront property owners' perceptions of coastal health and preferences for shoreline management. 2. Using mail-in and online surveys, we targeted over 3000 waterfront property owners across four jurisdictions experiencing or anticipating mangrove encroachment. 3. Our findings revealed a nuanced perception of coastal health, with many respondents recognizing the potentially environmental impacts of mangrove encroachment but favouring low-cost management strategies, such as maintaining current shoreline or passive monitoring. This reluctance to engage in active management highlights a perception-behaviour gap, likely influenced by the gradual nature of mangrove transitions, which diminishes urgency for active intervention. 4. Socio-demographic factors such as age, gender, income, residency and reliance on coastal resources significantly shaped preferences for shoreline management and regional responses. These preferences varied across jurisdictions, reflecting the importance of incorporating localized community values into management decisions. 5. Our findings highlight the need for a balanced approach to shoreline management that integrates ecological insights with the socio-cultural priorities of local communities. By aligning adaptation strategies with regional perceptions and values, it is possible to protect individual properties while enhancing the long-term resilience of coastal ecosystems under climate change pressures.

Florida, Texas↗

USGS2021

The 4th paradigm in multiscale data representation: Modernizing the National Geospatial Data Infrastructure

The need of citizens in any nation to access geospatial data in readily usable form is critical to societal well-being, and in the United States (US), demands for information by scientists, students, professionals and citizens continue to grow. Areas such as public health, urbanization, resource management, economic development and environmental management require a variety of data collected from many sources to identify problems, monitor trends and propose solutions. Such information needs and demands have driven the coordination of federal and regional government agencies with respective private sector participation to develop national geospatial data infrastructures in many countries.

Book chapter↗

USGS2017

Mercury contamination and stable isotopes reveal variability in foraging ecology of generalist California gulls

Environmental contaminants are a concern for animal health, but contaminant exposure can also be used as a tracer of foraging ecology. In particular, mercury (Hg) concentrations are highly variable among aquatic and terrestrial food webs as a result of habitat- and site-specific biogeochemical processes that produce the bioaccumulative form, methylmercury (MeHg). We used stable isotopes and total Hg (THg) concentrations of a generalist consumer, the California gull ( Larus californicus ), to examine foraging ecology and illustrate the utility of using Hg contamination as an ecological tracer under certain conditions. We identified four main foraging clusters of gulls during pre-breeding and breeding, using a traditional approach based on light stable isotopes. The foraging cluster with the highest δ 15 N and δ 34 S values in gulls (cluster 4) had mean blood THg concentrations 614% (pre-breeding) and 250% (breeding) higher than gulls with the lowest isotope values (cluster 1). Using a traditional approach of stable-isotope mixing models, we showed that breeding birds with a higher proportion of garbage in their diet (cluster 2: 63–82% garbage) corresponded to lower THg concentrations and lower δ 15 N and δ 34 S values. In contrast, gull clusters with higher THg concentrations, which were more enriched in 15 N and 34 S isotopes, consumed a higher proportion of more natural, estuarine prey. δ 34 S values, which change markedly across the terrestrial to marine habitat gradient, were positively correlated with blood THg concentrations in gulls. The linkage we observed between stable isotopes and THg concentrations suggests that Hg contamination can be used as an additional tool for understanding animal foraging across coastal habitat gradients.

Ecological Indicators↗

USGS2016

Volcanic air pollution over the Island of Hawai'i: Emissions, dispersal, and composition. Association with respiratory symptoms and lung function in Hawai'i Island school children

Background Kilauea Volcano on the Island of Hawai'i has erupted continuously since 1983, releasing approximately 300–12000 metric tons per day of sulfur dioxide (SO 2 ). SO 2 interacts with water vapor to produce an acidic haze known locally as “vog”. The combination of wind speed and direction, inversion layer height, and local terrain lead to heterogeneous and variable distribution of vog over the island, allowing study of respiratory effects associated with chronic vog exposure. Objectives We characterized the distribution and composition of vog over the Island of Hawai'i, and tested the hypotheses that chronic vog exposure (SO 2 and acid) is associated with increased asthma prevalence, respiratory symptoms, and reduced pulmonary function in Hawai'i Island schoolchildren. Methods We compiled data of volcanic emissions, wind speed, and wind direction over Hawai'i Island since 1992. Community-based researchers then measured 2- to 4-week integrated concentrations of SO 2 and fine particulate mass and acidity in 4 exposure zones, from 2002 to 2005, when volcanic SO 2 emissions averaged 1600 metric tons per day. Concurrently, community researchers recruited schoolchildren in the 4th and 5th grades of 25 schools in the 4 vog exposure zones, to assess determinants of lung health, respiratory symptoms, and asthma prevalence. Results Environmental data suggested 4 different vog exposure zones with SO 2 , PM2.5, and particulate acid concentrations (mean ± s.d.) as follows: 1) Low (0.3 ± 0.2 ppb, 2.5 ± 1.2 μg/m 3 , 0.6 ± 1.1 nmol H +/m 3 ), 2) Intermittent (1.6 ± 1.8 ppb, 2.8 ± 1.5 μg/m 3 , 4.0 ± 6.6 nmol H +/m 3 ), 3) Frequent (10.1 ± 5.2 ppb, 4.8 ± 1.9 μg/m 3 , 4.3 ± 6.7 nmol H +/m 3 ), and 4) Acid (1.2 ± 0.4 ppb, 7.2 ± 2.3 μg/m 3 , 25.3 ± 17.9 nmol H +/m 3 ). Participants (1957) in the 4 zones differed in race, prematurity, maternal smoking during pregnancy, environmental tobacco smoke exposure, presence of mold in the home, and physician-diagnosed asthma. Multivariable analysis showed an association between Acid vog exposure and cough and strongly suggested an association with FEV1/FVC < 0.8, but not with diagnosis of asthma, or chronic persistent wheeze or bronchitis in the last 12 months. Conclusions: Hawai'i Island's volcanic air pollution can be very acidic, but contains few co-contaminants originating from anthropogenic sources of air pollution. Chronic exposure to acid vog is associated with increased cough and possibly with reduced FEV1/FVC, but not with asthma or bronchitis. Further study is needed to better understand how volcanic air pollution interacts with host and environmental factors to affect respiratory symptoms, lung function, and lung growth, and to determine acute effects of episodes of increased emissions.

Hawai'i↗

USGS2023

Biocrusts indicators of livestock grazing effects on soil stability in sagebrush steppe: A case study from a long-term experiment in the northern Great Basin

Biocrusts are sensitive to changes in livestock grazing intensity in arid rangelands and may be useful indicators of ecosystem functions, particularly soil properties like soil stability, which may suggest the potential for soil erosion. We compared biocrust community composition and surface soil stability in a big sagebrush (Artemisia tridentata) steppe rangeland in the northwestern Great Basin in several paired sites, with or without long-term cattle grazing exclusion, and similar soils (mostly sandy loams), climate, and vegetation composition. We found that livestock grazing was associated with both lower surface soil stability and cover of several biocrust morphogroups, especially lichens, compared with sites with long-term livestock exclusion. Surface soil stability did not modify the effects of grazing on most biocrust components via interactive effects. Livestock grazing effects on total biocrust cover were partially mediated by changes in surface soil stability. Though lichens were more sensitive to grazing disturbance, our results suggest that moss (mostly Tortula ruralis in this site) might be a more readily observable indicator of grazing-related soil stability change in this area due to their relatively higher abundance compared with lichens (moss: mean, 8.5% cover, maximum, 96.1%, lichens: mean, 1.0% cover, maximum, 14.1%). These results highlight the potential for biocrust components as sensitive indicators of change in soil-related ecosystem functions in sagebrush steppe rangelands. However, further research is needed to identify relevant indicator groups across the wide range of biocrust community composition associated with site environmental characteristics, variable grazing systems, other rangeland health metrics, and other disturbance types such as wildfire.

Northern Great Basin↗

USGS2020

Macroinvertebrate oviposition habitat selectivity and egg-mass desiccation tolerances: Implications for population dynamics in large regulated rivers

Aquatic insects exhibit complex life cycles that include egg, larval, adult, and, in some instances, pupal stages. Disturbances at any of these life stages can affect overall population dynamics. Yet, efforts to understand the effects of disturbances, such as hydrologic alterations, overwhelmingly focus on the larval life stage of aquatic insects. We evaluated the potential for load-following flows associated with hydroelectric power production to act as a population bottleneck for aquatic insects via reductions in the availability and temporal persistence of optimal oviposition habitats. Specifically, we quantified the oviposition habitat selectivity of Baetis spp. (Baetidae), Brachycentrus occidentalis (Brachycentridae), Chironomidae (Diptera), and Hydropsyche occidentalis (Hydropsychidae) downstream of Flaming Gorge Dam, Utah, USA. We found that all taxa except H. occidentalis preferentially laid eggs on large emergent substrates located along the river edge. Peak discharge associated with load-following flows substantially reduced the number of emergent substrates available for oviposition, and daily low flows exposed eggs in these habitats to desiccation and drying. When subjected to experimental drying, both Baetis and H. occidentalis eggs experienced nearly 100% mortality after 2 h, whereas most B. occidentalis remained viable after 8 h. Our paired field and experimental results are consistent with the hypothesis that load-following flows from hydroelectric dams produce a population bottleneck for aquatic insects by short circuiting recruitment processes. Environmental flows that seek to improve the health of tailwater aquatic insect populations would benefit from consideration of habitat requirements for all life stages of aquatic insects.

Utah↗

USGS2019

Alaska Geochemical Database Version 3.0 (AGDB3)—Including “Best Value” Data Compilations for Rock, Sediment, Soil, Mineral, and Concentrate Sample Media

The Alaska Geochemical Database Version 3.0 (AGDB3) contains new geochemical data compilations in which each geologic material sample has one “best value” determination for each analyzed species, greatly improving speed and efficiency of use. Like the Alaska Geochemical Database Version 2.0 before it, the AGDB3 was created and designed to compile and integrate geochemical data from Alaska to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, element concentrations and associations, environmental impact assessments, and studies in public health associated with geology. This relational database, created from data-bases and published datasets of the U.S. Geological Survey (USGS), Atomic Energy Commission National Uranium Resource Evaluation (NURE), Alaska Division of Geological & Geophysical Surveys (DGGS), U.S. Bureau of Mines, and U.S. Bureau of Land Management serves as a data archive in support of Alaskan geologic and geochemical projects and contains data tables in several different formats describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 112 laboratory and field analytical methods on 396,343 rock, sediment, soil, mineral, heavy-mineral concentrate, and oxalic acid leachate samples. Most samples were collected by personnel of these agencies and analyzed in agency laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various agency programs and projects from 1938 through 2017. In addition, mineralogical data from 18,138 nonmagnetic heavy-mineral concentrate samples are included in this database. The AGDB3 includes historical geochemical data archived in the USGS National Geochemical Database (NGDB) and NURE National Uranium Resource Evaluation-Hydrogeochemical and Stream Sediment Reconnaissance databases, and in the DGGS Geochemistry database. Retrievals from these data-bases were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. In other words, the data of AGDB3 supersedes data in the AGDB and the AGDB2, but the background about the data in these two earlier versions are needed by users of the current AGDB3 to understand what has been done to amend, clean up, correct and format this data. Corrections were entered, resulting in a significantly improved Alaska geochemical dataset, the AGDB3. Data that were not previously in these databases because the data predate the earliest agency geochemical data-bases, or were once excluded for programmatic reasons, are included here in the AGDB3 and will be added to the NGDB and Alaska Geochemistry. The AGDB3 data provided here are the most accurate and complete to date and should be useful for a wide variety of geochemical studies. The AGDB3 data provided in the online version of the database may be updated or changed periodically.

Alaska↗

USGS2017

Phytoforensics—Using trees to find contamination

The water we drink, air we breathe, and soil we come into contact with have the potential to adversely affect our health because of contaminants in the environment. Environmental samples can characterize the extent of potential contamination, but traditional methods for collecting water, air, and soil samples below the ground (for example, well drilling or direct-push soil sampling) are expensive and time consuming. Trees are closely connected to the subsurface and sampling tree trunks can indicate subsurface pollutants, a process called phytoforensics. Scientists at the Missouri Water Science Center were among the first to use phytoforensics to screen sites for contamination before using traditional sampling methods, to guide additional sampling, and to show the large cost savings associated with tree sampling compared to traditional methods.

Fact Sheet↗

USGS2004

Chester County ground-water atlas, Chester County, Pennsylvania

Chester County encompasses 760 square miles in southeastern Pennsylvania. Groundwater-quality studies have been conducted in the county over several decades to address specific hydrologic issues. This report compiles and describes water-quality data collected during studies conducted mostly after 1990 and summarizes the data in a county-wide perspective. In this report, water-quality constituents are described in regard to what they are, why the constituents are important, and where constituent concentrations vary relative to geology or land use. Water-quality constituents are grouped into logical units to aid presentation: water-quality constituents measured in the field (pH, alkalinity, specific conductance, and dissolved oxygen), common ions, metals, radionuclides, bacteria, nutrients, pesticides, and volatile organic compounds. Water-quality constituents measured in the field, common ions (except chloride), metals, and radionuclides are discussed relative to geology. Bacteria, nutrients, pesticides, and volatile organic compounds are discussed relative to land use. If the U.S. Environmental Protection Agency (USEPA) or Chester County Health Department has drinking water standards for a constituent, the standards are included. Tables and maps are included to assist Chester County residents in understanding the water-quality constituents and their distribution in the county. Ground water in Chester County generally is of good quality and is mostly acidic except in the carbonate rocks and serpentinite, where it is neutral to strongly basic. Calcium carbonate and magnesium carbonate are major constituents of these rocks. Both compounds have high solubility, and, as such, both are major contributors to elevated pH, alkalinity, specific conductance, and the common ions. Elevated pH and alkalinity in carbonate rocks and serpentinite can indicate a potential for scaling in water heaters and household plumbing. Low pH and low alkalinity in the schist, quartzite, and gneiss rocks can indicate a potential for corrosive water. The only constituent measured in the field that has a USEPA Secondary Maximum Contaminant Level (SMCL) is pH. The SMCL for pH is 6.5-8.5; 64 percent of samples analyzed for pH were acidic (below pH 6.5). Only 1 percent of samples were basic (above pH 8.5). Of the common ions, the USEPA has SMCLs for chloride, sulfate, and total dissolved solids. The USEPA has a SMCL and a Primary Maximum Contaminant Level (PMCL) for fluoride. Chloride is more closely related to land use than geology. In Chester County, chloride exceeded the SMCL (250 mg/L) only in 5 percent of the services (commercial services, community services, and military) land-use areas. No samples analyzed for sulfate exceeded the SMCL (250 mg/L). Only 3 percent of samples analyzed for total dissolved solids exceeded the SMCL (500 milligrams per liter) (mg/L). No samples analyzed for fluoride equaled or exceeded the SMCL (2.0 mg/L) or PMCL (4.0 mg/L). Iron concentrations exceeded the USEPA SMCL in 11 percent of samples and were highest in schist (14 percent) and gneiss (13 percent). Manganese concentrations exceeded the SMCL in 19 percent of samples and were highest in quartzite and schist (both 28 percent). Lead and arsenic were present in low concentrations: the highest concentrations of lead occurred in water from quartzite (8 percent exceeded the USEPA Action Level), and arsenic was detected mostly in Triassic sedimentary rocks (9 percent exceeded the USEPA PMCL). The highest concentrations of copper occurred more frequently in quartzite rocks, and to a lesser extent were evenly distributed between ground water in gneiss, schist, and Triassic sedimentary rocks. Elevated concentrations of radon-222 and the combined radium-226/radium-228 radionuclides were common in water from quartzite and schist. Gross alpha and gross beta particle activities were elevated in water from quartzite and carbonate rocks. In contrast, elevated concentrations of uranium primarily were measured in water from Triassic sedimentary and carbonate rocks. Despite a sampling bias towards agricultural land use, only two samples indicated the presence of fecal coliforms. Samples analyzed for nutrients generally exhibited low concentrations, but about 11 percent of samples collected for nitrate exceeded the USEPA PMCL. Only one nitrite sample (less than 1 percent) exceeded the respective USEPA PMCL. Approximately 190 samples were collected for each of the three pesticides in this report: lindane, dieldrin, and diazinon. Sampling was biased towards agricultural, low-medium density residential, and wooded land uses. Approximately 95 percent of samples for each pesticide were below minimum reporting levels (MRL). Only lindane has a USEPA PMCL, and only one sample exceeded the standard. Results for dieldrin and diazinon were similar, except results for two diazinon samples where concentrations were 57.0 and 490 micrograms per liter (μg/L). Volatile organic compounds in this report were analyzed in water from 198 samples. Sampling was biased towards agricultural, low-medium density residential, and wooded land uses. Two percent of samples analyzed for trichloroethylene and less than 1 percent of samples analyzed for tetrachloroethylene exceeded their respective USEPA PMCLs (each 5.0 μg/L). No samples analyzed for 1,1,1-trichloroethane exceeded the USEPA PMCL (200 μg/L). No samples analyzed for methyl tert-butyl ether exceeded the USEPA Drinking Water Advisory (20μg/L).

Open-File Report↗

USGS1995

A preliminary assessment of the occurrence and possible sources of MTBE in ground water of the United States, 1993-94

The 1990 Clean Air Act Amendments require fuel oxygenates to be added to gasoline used in some metropolitan areas to reduce atmospheric concen- trations of carbon monoxide or ozone. Methyl tert-butyl ether (MTBE), is the most commonly used fuel oxygenate and is a relatively new gasoline additive. Nevertheless, out of 60 volatile organic chemicals analyzed, MTBE was the second most frequently detected chemical in samples of shallow ambient ground water from urban areas that were collected during 1993-94 as part of the U.S. Geological Survey's National Water-Quality Assessment program. Samples were collected from 5 drinking-water wells, 12 springs, and 193 monitoring wells in urban areas. No MTBE was detected in drinking-water wells. At a reporting level of 0.2 ug/L (micrograms per liter), MTBE was detected most frequently in shallow ground water from urban areas (27 percent of 210 wells and springs sampled in 8 areas) as compared to shallow ground water from agricultural areas (1.3 percent of 549 wells sampled in 21 areas) or deeper ground water from major aquifers (1 percent of 412 wells sampled in 9 areas). Only 3 percent of the shallow wells sampled in urban areas had concentrations of MTBE that exceed 20 ug/L, which is the estimated lower limit of the U.S. Environmental Protection Agency draft drinking-water health advisory. Because MTBE is persistent and mobile in ground water, it can move from shallow to deeper aquifers with time. In shallow urban ground water, MTBE generally was not found with benzene, toluene, ethylbenzene, or xylenes (BTEX) compounds which commonly are associated with gasoline spills. This disassociation causes uncertainty as to the source of MTBE. Possible sources of MTBE in ground water include point sources, such as leaking storage tanks, and nonpoint sources, such as recharge of precipitation and storm-water runoff.

Open-File Report↗

USGS2006

Spatial variations in fish-tissue mercury concentrations in the St. Croix River basin, Minnesota and Wisconsin, 2004

Parts of the St. Croix River in Minnesota and Wisconsin are under fish-consumption advisories because of elevated mercury concentrations that have been measured in fish from this river. The U.S. Geological Survey, National Park Service, and the University of Wisconsin, LaCrosse, cooperated in a study to determine the spatial variation of mercury in fish in the St. Croix River and selected tributaries. Game and nongame fish were collected at 14 sites during summer 2004 and identified to species. One hundred ninety-three (193) composite tissue samples were analyzed for total mercury as whole fish, skin-on fillet, or skin-off fillet. A model of mercury in fish was used to standardize fish-tissue mercury concentrations to a common species, tissues sampled, and length of fish allowing for more consistent comparisons among sites. Rush Creek near Rush City, Minnesota, was identified as having high median standardized fish-tissue mercury concentrations compared to other tributaries sampled. Previous studies identified Rush Creek as having high concentrations of methylmercury in water and high concentrations of total mercury in sediment when compared to other sites in the St. Croix River Basin. Sites in the St. Croix River Basin that drained forest/wetland watersheds had significantly higher median fish-tissue mercury concentrations than sites draining agricultural/forested watersheds (p=0.0003). There also was a significant relation between fish-tissue mercury concentration and methylmercury concentration in water (rho=0.580, p=0.02) and between fish-tissue mercury and total mercury in sediment (rho=0.569, p=0.03). Observed fish-tissue mercury concentrations exceeding the U.S. Environmental Protection Agency’s (USEPA) human-health criterion of 300 micrograms per kilogram occurred at 7 of the 14 sampling sites. The model predicted concentrations exceeding USEPA’s criterion at all of the seven sites where exceedances were observed and four of the seven sites where exceedances were not observed. The implication is that fish-consumption advisories that are based on observed concentrations (of a subset of the species that occur at the site or smaller fish) could underestimate the threat to human health. Using the model to predict fish-tissue mercury concentrations allows site-specific fish-consumption advisories to be developed for multiple species and different lengths of fish. Potential mercury exposure to fish consumers may be reduced because an individual can choose to consume sizes and species of fish that are expected to have lower fish-tissue mercury concentrations. The National Park Service can use these results to more reliably monitor fish-tissue mercury concentrations in the St. Croix River Basin and better assess potential health effects of fish consumption to humans and wildlife.

Minnesota, Wisconsin↗

USGS2009

Pesticides in ground water in selected agricultural land-use areas and hydrogeologic settings in Pennsylvania, 2003-07

This report was prepared by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Agriculture (PDA) as part of the Pennsylvania Pesticides and Ground Water Strategy (PPGWS). Monitoring data and extensive quality-assurance data on the occurrence of pesticides in ground water during 2003–07 are presented and evaluated; decreases in the land area used for agriculture and corresponding changes in the use of pesticides also are documented. In the Pennsylvania ground waters assessed since 2003, concentrations of pesticides did not exceed any maximum contaminant or health advisory levels established by the U.S. Environmental Protection Agency; PPGWS actions are invoked by the PDA at fractions of these levels and were needed only in areas designated by the PDA for special ground-water protection. Previous investigations through 1998 of pesticides in Pennsylvania ground water identified land use, as a surrogate for pesticide use, and rock type of the aquifer combined with physiography as key hydrogeologic setting variables for understanding aquifer vulnerability to contamination and the common occurrence of atrazine and metolachlor in ground water. Of 20 major hydrogeologic settings in a framework established in 1999 for pesticide monitoring in Pennsylvania, 9 were identified as priorities for data collection in order to change the monitoring status from "inadequate" to "adequate" for the PPGWS. Agricultural and forested land-use areas are decreasing because of urban and suburban growth. In the nine hydrogeologic settings evaluated using 1992 and 2001 data, decreases of up to 12 percent for agricultural land and 10 percent for forested land corresponded to increases of up to 11 percent for urban land. Changes in agricultural pesticide use were computed from crop data. For example, from 1996 to 2004–05, atrazine use declined by about 15 percent to 1,314,000 lb/yr (pounds per year) and metolachlor use increased by about 20 percent to 895,000 lb/yr; these compounds are the two most-used agricultural pesticides statewide. In 2003–07, a baseline assessment of pesticides was conducted in five of nine hydrogeologic settings with inadequate monitoring data—the Blue Ridge crystalline and Triassic Lowland siliciclastic, Eastern Lake surficial, Devonian-Silurian carbonate, Great Valley siliciclastic, and Northeastern Glaciated surficial settings. Between 20 and 30 wells in each setting were monitored. Of the 126 wells sampled, 96 well-water samples were analyzed for at least 52 pesticide compounds at the USGS National Water Quality Laboratory (NWQL) using a method with a minimum reporting level (MRL) at or above 0.002 µg/L (micrograms per liter). Of the 96 well waters analyzed by NWQL, 43 had measureable concentrations of one or more pesticides. Atrazine and (or) deethylatrazine (CIAT), a degradation product of atrazine, were reported at or above the MRL in 39 of the 43 well waters. Neither atrazine nor CIAT were reported at concentrations exceeding 0.10 µg/L; all measured concentrations in these five settings were below PPGWS action levels. Metolachlor was present in 7 of the 43 well waters with measureable concentrations of 1 or more pesticides; however, concentrations were below the MRL. The other 30 samples (10 of 20 wells in the Blue Ridge crystalline and Triassic Lowland siliciclastic setting and all 20 wells in the Eastern Lake surficial setting) were analyzed for at least 19 pesticide compounds at the Pennsylvania Department of Environmental Protection Laboratory (PADEPL); the PADEPL reported no concentrations of pesticides at or above an MRL of 0.10 µg/L. Statistical tests using the NWQL analytical results showed correlations between pesticide occurrence and two indicators of water-quality degradation—the occurrence of total coliform bacteria and nitrate concentration. A 2 × 2 contingency-table test indicated a relation between presence or absence of atrazine or metolachlor and presence or absence of bacteria only for the 10 wells representing the Blue Ridge crystalline and Triassic Lowland siliciclastic setting. Results of Spearman’s rank test showed strong positive correlations in the Devonian-Silurian carbonate setting between 1) the number of pesticides above the MRLs and nitrate concentration, and 2) concentrations of atrazine and nitrate. Atrazine concentration and nitrate concentration also showed a statistically significant positive correlation in the Great Valley siliciclastic setting. An additional component of baseline monitoring was to evaluate changes in pesticide concentration in water from wells representing hydrogeologic settings most vulnerable to contamination from pesticides. In 2003, 16 wells originally sampled in the 1990s were resampled—4 each in the Appalachian Mountain carbonate, Triassic Lowland siliciclastic, Great Valley carbonate, and Piedmont carbonate settings. Nine of these wells, where pesticide concentrations from 1993 and 2003 were analyzed at the NWQL, were chosen for a paired-sample analysis using concentrations of atrazine and metolachlor. A statistically significant decrease in atrazine concentration was identified using the Wilcoxon signed-rank test (p = 0.004); significant temporal changes in metolachlor concentrations were not observed (p = 0.625). Monitoring in three areas of special ground-water protection, where selected pesticide concentrations in well water were at or above the PPGWS action levels, was done at wells BE 1370 (Berks County, Oley Township), BA 437 (Blair County, North Woodbury Township), and LN 1842 (Lancaster County, Earl Township). Co-occurrence of pesticide-degradation products with parent compounds was documented for the first time in ground-water samples collected from these three wells. Degradation products of atrazine, cyanazine, acetochlor, alachlor, and metolachlor were commonly at larger concentrations than the parent compound in the same water sample. Pesticide occurrence in water from wells neighboring the hot-spot wells was highly variable; however, the same sets of pesticide compounds that were present in wells BA 437, BE 1370, and LN 1842 were present to some degree in water from neighboring wells. To evaluate temporal changes in concentration, nonparametric statistical tests were used to determine overall and seasonal monotonic trends. Concentrations of alachlor, atrazine, metolachlor, and nitrate were examined using the 5-year (2003–07) and the long-term data from wells BA 437 and LN 1842 (1996–2007 and 1995–2007, respectively), and the long-term data for well BE 1370 (1998–2007); results showed either downward trends or no trends. Trends in acetochlor concentrations were tested only at well LN 1842 using the 5-year data; no trends were observed. Homogeneity of trend tests indicated statistically significant downward concentration trends in the long-term data were due to seasonal trends as follows: BA 437—alachlor and atrazine (summer); BE 1370—atrazine and metolachlor (winter) and alachlor (winter and spring); LN 1842—alachlor (summer and fall) and atrazine (spring and fall).

Pennsylvania↗

USGS2010

Surface-water quantity and quality, aquatic biology, stream geomorphology, and groundwater-flow simulation for National Guard Training Center at Fort Indiantown Gap, Pennsylvania, 2002-05

Base-line and long-term monitoring of water resources of the National Guard Training Center at Fort Indiantown Gap in south-central Pennsylvania began in 2002. Results of continuous monitoring of streamflow and turbidity and monthly and stormflow water-quality samples from two continuous-record long-term stream sites, periodic collection of water-quality samples from five miscellaneous stream sites, and annual collection of biological data from 2002 to 2005 at 27 sites are discussed. In addition, results from a stream-geomorphic analysis and classification and a regional groundwater-flow model are included. Streamflow at the facility was above normal for the 2003 through 2005 water years and extremely high-flow events occurred in 2003 and in 2004. Water-quality samples were analyzed for nutrients, sediments, metals, major ions, pesticides, volatile and semi-volatile organic compounds, and explosives. Results indicated no exceedances for any constituent (except iron) above the primary and secondary drinking-water standards or health-advisory levels set by the U.S. Environmental Protection Agency. Iron concentrations were naturally elevated in the groundwater within the watershed because of bedrock lithology. The majority of the constituents were at or below the method detection limit. Sediment loads were dominated by precipitation due to the remnants of Hurricane Ivan in September 2004. More than 60 percent of the sediment load measured during the entire study was transported past the streamgage in just 2 days during that event. Habitat and aquatic-invertebrate data were collected in the summers of 2002-05, and fish data were collected in 2004. Although 2002 was a drought year, 2003-05 were above-normal flow years. Results indicated a wide diversity in invertebrates, good numbers of taxa (distinct organisms), and on the basis of a combination of metrics, the majority of the 27 sites indicated no or slight impairment. Fish-metric data from 25 sites indicated results similar to the invertebrate data. Stream classification based on evolution of the stream channels indicates about 94 percent of the channels were considered to be in equilibrium (type B or C channels), neither aggrading nor eroding. A regional, uncalibrated groundwater-flow model indicated the surface-water and groundwater-flow divides coincided. Because of folding of rock layers, groundwater was under confined conditions and nearly all the water leaves the facility via the streams.

Scientific Investigations Report↗

USGS2015

Water-quality characteristics in runoff for three discovery farms in North Dakota, 2008-12

The U.S. Geological Survey, in cooperation with North Dakota State University Agriculture Research Extension and in collaboration with North Dakota State Department of Health, North Dakota State Water Commission, U.S. Environmental Protection Agency, and several agricultural producers, helped organize a Discovery Farms program in North Dakota in 2007. Discharge measurements and water-quality samples collected at the three Farms (Underwood, Dazey, and Embden) were used to describe water-quality characteristics in runoff, and compute estimates of annual loads and yields for selected constituents from spring 2008 through fall 2012. Consistent patterns in water quality emerged at each individual farm, but similarities among farms also were observed. Suspended sediment, total phosphorus, and ammonia concentrations generally decreased downstream from feeding areas, and were primarily affected by surface runoff processes such as dilution, settling out of sediment, or vegetative uptake. Because surface runoff affects these constituents, increased annual surface runoff volume tended to result in increased loads and yields. No significant change in nitrate plus nitrite concentration were observed downstream from feeding areas because additional processes such as high solubility, nitrification, denitrification, and surface-groundwater interaction affect nitrate plus nitrite. For nitrate plus nitrite, increases in annual runoff volume did not consistently relate to increases in annual loads and yields. It seems that temporal distribution of precipitation and surface-groundwater interaction affected nitrate plus nitrite loads and yields. For surface drainage sites, the primary form of nitrogen was organic nitrogen whereas for subsurface drainage sites, the primary form of nitrogen was nitrate plus nitrite nitrogen.

North Dakota↗

USGS2016

Perchlorate and selected metals in water and soil within Mount Rushmore National Memorial, South Dakota, 2011–15

Mount Rushmore National Memorial is located in the east-central part of the Black Hills area of South Dakota and is challenged to provide drinking water to about 3 million annual visitors and year-round park personnel. An environmental concern to water resources within Mount Rushmore National Memorial has been the annual aerial fireworks display at the memorial for the Independence Day holiday during 1998–2009. A major concern of park management is the contamination of groundwater and surface water by perchlorate, which is used as an oxidizing agent in firework displays. A study by the U.S. Geological Survey, in cooperation with the National Park Service, was completed to characterize the occurrence of perchlorate and selected metals (constituents commonly associated with fireworks) in groundwater and surface water within and adjacent to Mount Rushmore National Memorial during 2011–15. Concentrations of perchlorate and metals in 106 water samples (collected from 6 groundwater sites and 14 surface-water sites) and 11 soil samples (collected from 11 soil sites) are reported. Within the Mount Rushmore National Memorial boundary, perchlorate concentrations were greatest in the Lafferty Gulch drainage basin, ranging from less than 0.20 to 38 micrograms per liter (μg/L) in groundwater samples and from 2.2 to 54 μg/L in surface-water samples. Sites within the Starling Gulch drainage basin also had some evidence of perchlorate contamination, with concentrations ranging from 0.61 to 19 μg/L. All groundwater and surface-water samples within the unnamed tributary to Grizzly Bear Creek drainage basin and reference sites outside the park boundary had concentrations less than 0.20 μg/L. Perchlorate concentrations in samples collected at the 200-foot-deep production well (Well 1) ranged from 17 to 38 μg/L with a median of 23 μg/L, whereas perchlorate concentrations in samples from the 500-foot-deep production well (Well 2) ranged from 2.1 to 17 μg/L, with a median of 6.1 μg/L. Perchlorate concentrations in samples of the treated groundwater were similar to the concentrations from Well 1, which was the predominant source of the water supply at Mount Rushmore National Memorial during the study period (2011–15). Springflow upstream from the production wells in the West Fork Lafferty Gulch drainage had the greatest perchlorate concentrations, ranging from 21 to 54 μg/L. The groundwater site within Lafferty Gulch drainage basin but downstream from the park boundary also had a perchlorate concentration less than 0.20 μg/L in the one sample collected at the site. Water samples collected at reference sites generally had concentrations of metals within the same range of those sites within the Mount Rushmore National Memorial boundary, presenting little evidence of metal contamination due to anthropogenic factors within the park boundary. Soil samples were collected near most water sampling sites and within the Hall of Records Canyon where fireworks were launched. Perchlorate concentrations in soil were greatest in the West Fork Lafferty Gulch drainage and Hall of Records Canyon, which are topographically higher than the two groundwater wells. The perchlorate concentrations in groundwater and surface water within Lafferty Gulch drainage basin during 2011–15 were greater than the U.S. Environmental Protection Agency’s Interim Drinking Water Health Advisory benchmark of 15 μg/L. The perchlorate concentrations in the Mount Rushmore water supply relative to this benchmark are of concern; however, this health advisory is based on the assumption that consumers are using the supply as their primary water source and currently is not a regulated standard. The groundwater system at West Fork Lafferty Gulch is highly susceptible to contamination by way of recharge and is isolated from downstream movement by an intrusive body acting as a dam, which may explain why a contamination problem is not likely to disappear or disperse, as could happen in larger aquifer systems. The observed deposition of firework debris within Lafferty Gulch drainage basin coupled with the lack of alternative perchlorate sources indicates that past firework displays are the most probable source of perchlorate contamination.

South Dakota↗

USGS2020

Groundwater quality in relation to drinking water health standards and hydrogeologic and geochemical characteristics for 47 domestic wells in Potter County, Pennsylvania, 2017

As part of a regional effort to characterize groundwater in rural areas of Pennsylvania, water samples from 47 domestic wells in Potter County were collected from May through September 2017. The sampled wells had depths ranging from 33 to 600 feet in sandstone, shale, or siltstone aquifers. Groundwater samples were analyzed for physicochemical properties that could be evaluated in relation to drinking-water health standards, geology, land use, and other environmental factors. Laboratory analyses included concentrations of major ions, nutrients, bacteria, trace elements, volatile organic compounds (VOCs), ethylene and propylene glycol, alcohols, gross-alpha/beta-particle activity, uranium, radon-222, and dissolved gases. A subset of samples was analyzed for radium isotopes (radium-226 and -228) and for the isotopic composition of methane. Results of this 2017 study show that groundwater quality generally met most drinking-water standards that apply to public water supplies. However, a percentage of samples exceeded maximum contaminant levels (MCLs) for total coliform bacteria (69.6 percent), Escherichia coli (30.4 percent), arsenic, and barium; and secondary maximum contaminant levels (SMCLs) for field pH, manganese, sodium, iron, total dissolved solids, aluminum, and chloride. All of the analyzed VOCs were below limits of detection and associated drinking water criteria. Radon-222 activities exceeded the proposed drinking-water standard of 300 picocuries per liter in 80.9 percent of the samples. The field pH of the groundwater ranged from 4.6 to 9.0. Generally, the lower pH samples had greater potential for elevated concentrations of dissolved metals, including beryllium, copper, lead, nickel, and zinc, whereas the higher pH samples had greater potential for elevated concentrations of total dissolved solids, sodium, fluoride, boron, and uranium. Near-neutral samples (pH 6.5 to 7.5) had greater hardness and alkalinity concentrations than other samples with pH values outside this range. Calcium/bicarbonate waters were the predominant hydrochemical type for the sampled aquifers, with mixed water types for many samples, including variable contributions from calcium, magnesium, and sodium combined with bicarbonate, sulfate, chloride, and nitrate. Water from 45 wells had concentrations of methane greater than the 0.0002 milligrams per liter (mg/L) detection limit. One sample had the maximum value of 11 mg/L, which exceeds the Pennsylvania action level of 7 mg/L. Additionally, three other samples had concentrations of methane greater than 4 mg/L. Outgassing of such levels of methane from the water to air within a confined space can result in a potential hazard. The elevated concentrations of methane generally were associated with suboxic groundwater (dissolved oxygen less than 0.5 mg/L) that had near-neutral to alkaline pH with relatively elevated concentrations of iron, manganese, ammonia, lithium, fluoride, and boron. Other constituents, including barium, sodium, chloride, and bromide, commonly were elevated, but not limited to, those well-water samples with elevated methane. Low levels of ethane (as much as 1.2 mg/L) were present in eight samples with the highest methane concentrations. Five samples were analyzed for methane isotopes. The isotopic and hydrocarbon compositions in these five samples suggest the methane may be of microbial origin or a mixture of thermogenic and microbial gas, but differed from the compositions reported for mud-gas logging samples collected during drilling of gas wells. The concentrations of sodium (median 8.2 mg/L), chloride (median 7.64 mg/L), and bromide (median 0.02 mg/L) for the 47 groundwater samples collected for this study ranged widely and were positively correlated with one another and with specific conductance and associated measures of ionic strength. Sixty percent of the Potter County well-water samples had chloride concentrations less than 10 mg/L. Samples with higher chloride concentrations had variable bromide concentrations and corresponding chloride/bromide ratios that are consistent with sources such as road-deicing salt and septic effluent (low bromide) or brine (high bromide). Brines are naturally present in deeper parts of the regional groundwater system and, in some cases, may be mobilized by gas drilling. It is also possible that valley wells were drilled close to or into the brine-freshwater interface, so brine signatures do not necessarily indicate contamination due to drilling. The chloride, bromide, and other constituents in road-deicing salt or brine solutions tend to be diluted by mixing with fresh groundwater in shallow aquifers used for water supply. Although 1 of 8 groundwater samples with the highest methane concentrations (greater than 0.2 mg/L) had concentrations of chloride and bromide with corresponding chloride/bromide ratios that indicated mixing with road-deicing salt, the other 7 of 8 samples with elevated methane had concentrations of chloride and bromide with corresponding chloride/bromide ratios that indicated mixing with a small amount of brine (0.02 percent or less) similar in composition to those reported for gas and oil well brines in Pennsylvania. In several eastern Pennsylvania counties where gas drilling is absent, groundwater with comparable chloride/bromide ratios and chloride concentrations have been reported. Approximately 50 percent of Potter County well-water samples, including two samples with the fourth (72.9 mg/L) and fifth (47.0 mg/L) highest chloride concentrations, have chloride/bromide ratios that indicate predominantly anthropogenic sources of chloride, such as road-deicing salt or septic effluent.

Pennsylvania↗