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USGS2016

New perspectives on a 140-year legacy of mining and abandoned mine cleanup in the San Juan Mountains, Colorado

The Gold King mine water release that occurred on 5 August 2015 near the historical mining community of Silverton, Colorado, highlights the environmental legacy that abandoned mines have on the environment. During reclamation efforts, a breach of collapsed workings at the Gold King mine sent 3 million gallons of acidic and metal-rich mine water into the upper Animas River, a tributary to the Colorado River basin. The Gold King mine is located in the scenic, western San Juan Mountains, a region renowned for its volcano-tectonic and gold-silver-base metal mineralization history. Prior to mining, acidic drainage from hydrothermally altered areas was a major source of metals and acidity to streams, and it continues to be so. In addition to abandoned hard rock metal mines, uranium mine waste poses a long-term storage and immobilization challenge in this area. Uranium resources are mined in the Colorado Plateau, which borders the San Juan Mountains on the west. Uranium processing and repository sites along the Animas River near Durango, Colorado, are a prime example of how the legacy of mining must be managed for the health and well-being of future generations. The San Juan Mountains are part of a geoenvironmental nexus where geology, mining, agriculture, recreation, and community issues converge. This trip will explore the geology, mining, and mine cleanup history in which a community-driven, watershed-based stakeholder process is an integral part. Research tools and historical data useful for understanding complex watersheds impacted by natural sources of metals and acidity overprinted by mining will also be discussed.

Colorado↗

USGS2005

Gulf of Mexico integrated science - Tampa Bay study, the impact of groundwater and contaminants on Tampa Bay

Despite the recreational and economic value of coastal bays and estuaries, these ecosystems are often among our most 'troubled' natural environments. Urbanization, agriculture, mining, and shipping are just a few activities that can have a profound and lasting impact on the coastal zone. In order to maintain a healthy coastal ecosystem, it is crucial to develop reasonable management practices around expert scientific information. We still have much to learn about the quantity and quality of groundwater being discharged into Tampa Bay, Florida. We also need to improve our knowledge of a wide range of contaminants entering the bay and must be able to determine where they accumulate in seafloor sediments. Such buried contaminants can potentially be harmful to biota if they are released to the water column. U.S. Geological Survey (USGS) scientists and research partners from the University of South Florida (USF), the University of Florida (UF), and the Florida Marine Research Institute (FMRI) are mapping sources of groundwater, measuring groundwater flow into Tampa Bay, and assessing the impact of contaminants and sediments on bay water quality and ecosystem health.

Open-File Report↗

USGS2010

Aquatic assessment of the Ely Copper Mine Superfund site, Vershire, Vermont

The Ely Mine, which operated from 1821 to 1905, and its area of downstream impact constitute the Ely Copper Mine Superfund site. The site was placed on the National Priorities List in 2001. The mine comprises underground workings, foundations from historical structures, several waste-rock piles, roast beds associated with the smelting operation, and slag piles resulting from the smelting. The mine site is drained by Ely Brook, which includes several tributaries, one of which drains a series of six ponds. Ely Brook empties into Schoolhouse Brook, which flows 3.3 kilometers and joins the Ompompanoosuc River. The aquatic ecosystem at the site was assessed using a variety of approaches that investigated surface-water quality, sediment quality, and various ecological indicators of stream-ecosystem health. The degradation of surface-water quality is dominated by copper with localized effects caused by iron, aluminum, cadmium, and zinc. Chronic water-quality criteria for copper are exceeded in the surface water of four of the six ponds on the Ely Brook tributary, and all of Ely Brook and Schoolhouse Brook, and of the Ompompanoosuc River downstream of the confluence with Schoolhouse Brook. Comparison of hardness-based and Biotic Ligand Model-based water-quality criteria for copper yields similar results with respect to extent of impairment. However, the Biotic Ligand Model criteria are mostly lower than the hardness-based criteria and thus suggest a greater degree of impairment, particularly in the Ely Brook watershed, where dissolved organic carbon concentrations and pH values are lower. Surface-water toxicity testing correlates strongly with the extent of impact. Likewise, riffle-habitat benthic invertebrate richness and abundance data support these results through the stream environment. Similarly, the index of biotic integrity for the fish community in Schoolhouse Brook and the Ompompanoosuc River document degraded habitats throughout Schoolhouse Brook from Ely Brook down to the Ompompanoosuc River. The sediment environment shows similar extents of impairment also dominated by copper, although localized degradation due to chromium, nickel, lead, and zinc was documented on the basis of probable effects concentrations. In contrast, equilibrium-partitioning sediment benchmarks indicate no toxic effects would be expected in sediments at the reference sites, and uncertain toxic effects throughout Ely Brook and Schoolhouse Brook, except for the reference sites and site EB-600M. The results for site EB-600M indicate predicted toxic effects. Acute toxicity testing of in situ pore waters using Hyalella azteca indicates severe impacts in Ely Brook reaching 100 percent lethality at site EB-90M. Acute toxicity testing of in situ pore waters using Chironomus dilutus shows similar, but not as severe, toxicity. Neither set of in situ pore-water toxicity tests showed significant impairment in Schoolhouse Brook or the Ompompanoosuc River. Chronic sediment toxicity testing using Hyalella azteca indicated significant toxicity in Ely Brook, except at site EB-90M, and in Schoolhouse Brook. The low toxicity of EB-90M may be a reflection of the low lability of copper in that sediment as indicated by a low proportion of extractable copper (1.1 percent). Depositional-targeted habitat invertebrate richness and abundance data support these conclusions for the entire watershed, as do the index of biotic integrity data from the fish community. The information was used to develop an overall assessment of the impact on the aquatic system that appears to be a result of the acid rock drainage at the Ely Mine. More than 700 meters of Ely Brook, including two of the six ponds, were found to be severely impacted, on the basis of water-quality data and biological assessments. The reference location was of good quality based on the water quality and biological assessment. More than 3,125 meters of Schoolhouse Brook are also severely impacted, on the basis of water-quality data and biological assessments. The biological community begins to recover near the confluence with the Ompompanoosuc River. The evidence is less conclusive regarding the Ompompanoosuc River. The sediment data suggest that the sediments could be a source of toxicity in Ely Brook and Schoolhouse Brook. The surface-water assessment is consistent with the outcome of a surface-water toxicity testing program performed by the U.S. Environmental Protection Agency for Ely Brook and Schoolhouse Brook and a surface-water toxicity testing program and in situ amphibian testing program for the ponds.

Vermont↗

USGS1996

Influences of environmental settings on aquatic ecosystems in the Apalachicola-Chattahoochee-Flint River basin

The watershed boundary of the Apalachicola-Chattahoochee-Flint (ACF) River basin defines an aquatic ecosystem whose water quality is the result of complex interactions of natural and human influences on land and water resources. Topics relating to the basin's environmental setting-its physical, biological, and cultural characteristics-are summarized to provide an understanding of factors that influence water quality and the health of aquatic ecosystems. The ACF River basin lies partly in southwestern Georgia, southeastern Alabama, and northwestern Florida and covers 19,800 square miles in the Blue Ridge, the Piedmont, and the Coastal Plain Provinces. The basin includes the drainages of the Chattahoochee River and the Flint River, which meet to form the Apalachicola River. The Apalachicola River flows into the Gulf of Mexico at Apalachicola Bay. Basin hydrology and water quality are influenced by 16 mainstem reservoirs, 13 of which are on the Chattahoochee River. Ground water in the basin is contained in six aquifers-the surficial aquifer system, the Floridan aquifer system, the Claiborne aquifer, the Clayton aquifer, the Providence aquifer, and the crystalline-rock aquifer. Physiography, climate, and hydrology of the ACF River basin provide natural conditions that support a rich and abundant diversity of plants and animals. Although most of the ACF River basin has been altered by human activities, the basin's environment is noteworthy for its remaining biological diversity and the role it plays in sustaining biological productivity in Apalachicola Bay. The Bay produces 90 percent of Florida's and 13 percent of the Nation's oyster harvest; and functions as a nursery for penaeid shrimp, blue crabs, and a variety of fin fish. The diversity of the basin's aquatic fauna is noteworthy because the basin is home to (1) the largest number of fish species among Gulf Coast drainages east of the Mississippi River, (2) the largest assemblage of freshwater fish in Florida, (3) the largest number of mollusc species among western Florida drainages, and (4) the highest species density of amphibians and reptiles on the continent north of Mexico. Population of the ACF River basin in 1990 was estimated at 2.6 million. Nearly 90 percent of the total population lived in Georgia, and nearly 60 percent lived in the Metropolitan Atlanta area. The 1990 basin population is projected to increase by 15 percent to 3.0 million by the year 2000, and by 30 percent to 3.4 million by 2010. The largest increases in populations are projected for the Metropolitan Atlanta area. In 1972-76, approximately 59 percent of the basin was covered by forest, 29 percent was agricultural, 5 percent was wetland, 4 percent was urban, and 3 percent was water or barren land. Most of the original land cover of the basin has been transformed by human activity. Timber is the basin's largest cash crop and most forests consist of second-growth stands or large acreages of planted pine. The dominant agricultural land use in the Piedmont Province is pasture and confined feeding for dairy, livestock, and poultry production. Row-crop agriculture, orchards, and silviculture are most common in the Coastal Plain Province. The top five crops in order from most to least acres harvested in 1990 were peanuts, corn, soybeans, wheat, and cotton. The water in the basin is used for public and industrial supply, irrigation, power generation, navigation, and recreation. Although most public-supply withdrawals in the Blue Ridge and Piedmont Provinces are from surface-water sources, with the exception of counties near or immediately below the Fall Line, all publicly supplied water in the Coastal Plain is withdrawn from ground-water sources. Ground water supplied 18 percent of the basin's population served by public supply. Total water withdrawn in the ACF River basin in 1990 was 2,098 million gallons per day (Mgal/d), of which Georgia withdrew 82 percent and Florida and Alabama each withdrew 9 percent. Power generation is the single largest water use. Sixteen of the basin's 22 power generating plants are located along the mainstem of the Chattahoochee River. The U.S. Army Corps of Engineers maintains a navigation channel from the mouth of the Apalachicola River to Columbus, Ga., on the Chattahoochee River and to Bainbridge, Ga., on the Flint River. Water quality in the basin is influenced by the operation of 137 municipal wastewater-treatment facilities. In 1990, 354 Mgal/d of municipal wastewater was discharged within the ACF River basin. Eighty-eight percent of the wastewater was discharged into the Chattahoochee River basin, 10.6 percent into the Flint River basin, and 1.4 percent into the Apalachicola River basin. Two-thirds of the 938 stream miles in the Georgia portion of the ACF River basin having water quality that does not meet or only partially meets the designated-use criteria in the Chattahoochee River basin. The Chattahoochee River is the most heavily-used water resource both in the ACF River basin and in Georgia. Urban runoff or unknown nonpoint sources are cited as the causes of water-quality regulations in 72 percent of violations. The remaining causes primarily are combined sewer overflows in the Atlanta area, and discharges from municipal or industrial treatment facilities with inadequate treatment capabilities or operational deficiencies.

Alabama, Florida, Georgia↗

USGS2011

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

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

Report↗

USGS2013

Validation of chlorine and oxygen isotope ratio analysis to differentiate perchlorate sources and to document perchlorate biodegradation

Report↗

USGS2020

Occurrence and geochemistry of lead-210 and polonium-210 radionuclides in public-drinking-water supplies from principal aquifers of the United States

On the basis of lifetime cancer risks, lead-210 ( 210 Pb) and polonium-210 ( 210 Po) ≥ 1.0 and 0.7 pCi/L (picocuries per liter), respectively, in drinking-water supplies may pose human-health concerns. 210 Pb and 210 Po were detected at concentrations greater than these thresholds at 3.7 and 1.5%, respectively, of filtered untreated groundwater samples from 1263 public-supply wells in 19 principal aquifers across the United States. Nationally, 72% of samples with radon-222 ( 222 Rn) concentrations > 4000 pCi/L had 210 Pb ≥ 1.0 pCi/L. 210 Pb is mobilized by alpha recoil associated with the decay of 222 Rn and short-lived progeny. 210 Pb concentrations ≥ 1.0 pCi/L occurred most frequently where acidic groundwaters inhibited 210 Pb readsorption (felsic-crystalline rocks) and where reducing alkaline conditions favored dissolution of iron–manganese- (Fe–Mn-) oxyhydroxides (which adsorb 210 Pb) and formation of lead–carbonate complexes (enhancing lead (Pb) mobility). 210 Po concentrations ≥ 0.7 pCi/L occurred almost exclusively in confined Coastal Plain aquifers where old (low percent-modern carbon-14) groundwaters were reducing, with high pH (>7.5) and high sodium/chloride (Na/Cl) ratios resulting from cation exchange. In high-pH environments, aqueous polonium (Po) is poorly sorbed, occurring as dihydrogen polonate (H 2 PoO 3 (aq)) or, under strongly reducing conditions, as a hydrogen-polonide anion (HPo – ). Fe–Mn- and sulfate-reduction and cation-exchange processes may mobilize polonium from mineral surfaces. Po 2+ occurrence in low-to-neutral-pH waters is attenuated by adsorption.

Environmental Science Technology↗

USGS2020

Waterfowl occurrence and residence time as indicators of H5 and H7 avian influenza in North American Poultry

Avian inﬂuenza (AI) affects wild aquatic birds and poses hazards to human health, food security, and wildlife conservation globally. Accordingly, there is a recognized need for new methods and tools to help quantify the dynamic interaction between wild bird hosts and commercial poultry. Using satellite-marked waterfowl, we applied Bayesian joint hierarchical modeling to concurrently model species distributions, residency times, migration timing, and disease occurrence probability under an integrated animal movement and disease distribution modeling framework. Our results indicate that migratory waterfowl are positively related to AI occurrence over North America such that as waterfowl occurrence probability or residence time increase at a given location, so too does the chance of a commercial poultry AI outbreak. Analyses also suggest that AI occurrence probability is greatest during our observed waterfowl northward migration, and less during the southward migration. Methodologically, we found that when modeling disparate facets of disease systems at the wildlife-agriculture interface, it is essential that multiscale spatial patterns be addressed to avoid mistakenly inferring a disease process or disease-environment relationship from a pattern evaluated at the improper spatial scale. The study offers important insights into migratory waterfowl ecology and AI disease dynamics that aid in better preparing for future outbreaks.

Scientific Reports↗

USGS2012

Threats and stressors to the health of the ecosystems of Lakes Mead and Mohave: Chapter 6 in A synthesis of aquatic science for management of Lakes Mead and Mohave

Ecosystem impacts from visitor activities or natural environmental change are important concerns in all units of the National Park system. Possible impacts to aquatic ecosystems at Lake Mead National Recreation Area (LMNRA) are of particular concern because of the designation of Lakes Mead and Mohave as critical habitat for the federally listed endangered razorback sucker (Xyrauchen texanus), the significance of the sport fishery, and the regional importance of its habitats to more than 90 documented species of waterbirds. Potential threats to shoreline habitats are of concern not only for their ecosystem values but also for maintaining the recreational setting. Many areas adjacent to the shorelines of Lakes Mead and Mohave are designated wilderness areas. For purposes of this document, stressors are any chemical, biological, or physical agent that has a detrimental effect on aquatic ecosystems at the organism, population, or community level. Human-made stressors at Lakes Mead and Mohave include direct effects of recreation on the lakes, like boating and fishing, as well as indirect effects of activities away from the lakes, such as growing population and increasing urbanization. Common natural environmental stressors include extended changes in climate (precipitation or temperature), or the erosion, transport, and loading of chemical constituents in rocks and sediments to aquatic environments. Human activity also can exacerbate natural stressors in a variety of ways.

Circular↗

USGS2020

Spatial and temporal patterns in streamflow, water chemistry, and aquatic macroinvertebrates of selected streams in Fairfax County, Virginia, 2007–18

Urbanization substantially alters the landscape in ways that can impact stream hydrology, water chemistry, and the health of aquatic communities. Stormwater best management practices (BMPs) are the primary tools used to mitigate the effects of urban stressors such as increased runoff, decreased baseflow, and increased nutrient and sediment transport. To date, Fairfax County Virginia’s stormwater management program has made substantial investments into the implementation of both structural and nonstructural BMPs aimed at restoring and protecting watersheds. The U.S. Geological Survey (USGS), in cooperation with Fairfax County, Virginia, established a long-term water-resources monitoring program to evaluate the watershed-scale effects of these investments. Monitoring began at 14 stations in 2007 and was expanded to 20 stations in 2013. This report utilized the first 10 years of data collection to (1) assess water quantity and quality, as well as ecological condition; (2) compute annual nutrient and sediment loads; and (3) evaluate trends in streamflow, water quality, and ecological condition. Efforts are underway to link the biotic and abiotic patterns described herein to watershed management practices as well as factors such as land use change, public works infrastructure, and climate. Hydrologic, chemical, and benthic macroinvertebrate community conditions in the streams monitored were similar to those observed in other studies of urban streams. Multidecadal trends in baseflow indices and runoff ratios at long-term Chesapeake Bay Non-tidal Network streamgages (CB-NTN) indicate a decrease in groundwater recharge and increase in storm runoff as a result of urbanization. Streamflow yields varied spatially with land cover, geology, and soil characteristics, whereas flashiness was positively related to impervious area. Dissolved oxygen typically was lowest in the Coastal Plain and across all Triassic Lowlands streams, and highest in the Piedmont. Dissolved oxygen concentrations generally were above Virginia’s minimum criterion of 4.0 milligrams per liter (mg/L), most violations occurred at Paul Spring Branch in the Coastal Plain during the warmest months of the year owing to increased chemical and biological oxygen demand. Typical pH values of the monitored streams centered on neutrality (pH = 7); however, diurnal fluctuations were most prevalent in the continuous pH data at Flatlick Branch (FLAT; a Triassic Lowlands station), as a result of increased photosynthesis catalyzed by phosphorus-rich geology. Specific conductance (SC) varied spatially owing to geology (highest at Triassic Lowlands stations) and anthropogenic disturbance (watersheds with high impervious land cover). Specific conductance typically was inversely related to streamflow except in winter months following deicing road salt applications, when values increased by several orders of magnitude. A significant increase in SC of about 2 percent per year was observed from the combined trend result of all monitoring stations over the 10-year period. Significant SC increases occurred at nearly all monitoring stations. Increasing trends were observed during winter and nonwinter months, which suggests that salts applied to deice roadways and other impervious surfaces are stored in the environment and released year-round. Suspended-sediment (SS) concentrations in monthly samples did not vary significantly between most stations, but typically were highest in the spring and lowest in the fall as a result of seasonal differences in streamflow and climate. Suspended-sediment yields ranged from 62 to 1,428 tons per square mile (ton/mi 2 ), with a median of 302 ton/mi 2 . Annual loads were greatest during the wettest water years (October 1-September 30; 2008, 2011, and 2014), with the greatest interannual variability occurring at Difficult Run above Fox Lake (DIFF) and South Fork Little Difficult Run (SFLIL). Suspended sediment was primarily composed of silts and clays; however, the proportion of sand in suspended sediment was related positively to streamflow. Cross-correlation analyses suggested the dominant sources of SS were streambank erosion and resuspension of in-channel material at DIFF and FLAT; whereas, upland sources and erosion of upper streambanks were more common at Dead Run (DEAD), Long Branch (LONG), and SFLIL. Median total phosphorus (TP) concentrations ranged from 0.016 to 0.077 mg/L, with a networkwide median of 0.022 mg/L, were highest in the warm season (April-September), and were composed primarily of dissolved phosphorous. Although TP concentrations were relatively low across the network, the highest concentrations were consistently at stations located in the Triassic Lowlands, owing to phosphorous-rich geology, and in the Coastal Plain, owing to the low-phosphorous sorptive capacity of those soils. A significant increase in TP concentration occurred in a few stations, but the combined trend results from all stations demonstrated a significant increase of about 4 percent per year. Networkwide increases were also observed in total dissolved phosphorus, orthophosphate, and total particulate phosphorus. The composition of TP shifted from dissolved to particulate as streamflow increased and for this reason loads primarily were composed of particulate phosphorous. Median annual TP loads were highest at FLAT and DEAD and ranged from 247 to 642 pounds per square mile (lbs/mi 2 ) networkwide. Interannual variability in phosphorous yields was apparent at most stations; the highest loading years were also the wettest years during the study period and coincident with the highest peak annual flows. Total nitrogen (TN) concentrations typically were low throughout the network with exceptions occurring at stations located in watersheds with a high density of septic infrastructure. Elevated TN concentrations also were observed in some watersheds without a high density of septic systems and may be attributable to geologic and soil properties that limit denitrification as well as other unknown anthropogenic inputs. Total nitrogen typically was dominated by nitrate during baseflows; however, the proportion of particulate nitrogen increased during stormflows. Total nitrogen yields were similar across stations, with medians ranging from about 3,600 to 6,300 lbs/mi 2 and were related to annual streamflow volume. Total nitrogen concentrations and flow-normalized concentrations decreased over the 10-year period at 7 stations, with median reductions of about 2.5 percent. Increasing trends were observed at the two stations with the highest median TN concentration (Captain Hickory Run and SFLIL, 3–5 mg/L), both watersheds contain a high density of septic infrastructure. The combined trend results from all stations revealed no trend in TN and a declining trend in nitrate of about 2 percent per year. Overall, benthic community metrics indicated that streams throughout Fairfax County were initially of poor health; however, many metrics show an improving trend (from poor to fair based on the Fairfax County Index of Biological Integrity [IBI]). Significant increasing trends in IBI occurred at the network-scale and at 4 individual stations; additionally, scores improved by at least 1 qualitative category (for example, poor to fair, fair to good) at 11 of the 14 stations between 2009 (the first year all 14 stations were sampled) and 2017. Changes in all metrics suggest that the biodiversity, function, and condition of streams in Fairfax County are improving, but some of these improvements are driven by increased diversity and percent composition of organisms that are tolerant of the urban environment.

Virginia↗

USGS2013

Aquatic assessment of the Pike Hill Copper Mine Superfund site, Corinth, Vermont

The Pike Hill Copper Mine Superfund site in Corinth, Orange County, Vermont, includes the Eureka, Union, and Smith mines along with areas of downstream aquatic ecosystem impairment. The site was placed on the U.S. Environmental Protection Agency (USEPA) National Priorities List in 2004. The mines, which operated from about 1847 to 1919, contain underground workings, foundations from historical structures, several waste-rock piles, and some flotation tailings. The mine site is drained to the northeast by Pike Hill Brook, which includes several wetland areas, and to the southeast by an unnamed tributary that flows to the south and enters Cookville Brook. Both brooks eventually drain into the Waits River, which flows into the Connecticut River. The aquatic ecosystem at the site was assessed using a variety of approaches that investigated surface-water quality, sediment quality, and various ecological indicators of stream-ecosystem health. The degradation of surface-water quality is caused by elevated concentrations of copper, and to a lesser extent cadmium, with localized effects caused by aluminum, iron, and zinc. Copper concentrations in surface waters reached or exceeded the USEPA national recommended chronic water-quality criteria for the protection of aquatic life in all of the Pike Hill Brook sampling locations except for the location farthest downstream, in half of the locations sampled in the tributary to Cookville Brook, and in about half of the locations in one wetland area located in Pike Hill Brook. Most of these same locations also contained concentrations of cadmium that exceeded the chronic water-quality criteria. In contrast, surface waters at background sampling locations were below these criteria for copper and cadmium. Comparison of hardness-based and Biotic Ligand Model (BLM)-based criteria for copper yields similar results with respect to the extent or number of stations impaired for surface waters in the affected area. However, the BLM-based criteria are commonly lower values than the hardness-based criteria and thus suggest a greater degree or magnitude of impairment at the sampling locations. The riffle-habitat benthic invertebrate richness and abundance data correlate strongly with the extent of impact based on water quality for both brooks. Similarly, the fish community assessments document degraded conditions throughout most of Pike Hill Brook, whereas the data for the tributary to Cookville Brook suggest less degradation to this brook. The sediment environment shows similar extents of impairment to the surface-water environment, with most sampling locations in Pike Hill Brook, including the wetland areas, and the tributary to Cookville Brook affected. Sediment impairment is caused by elevated copper concentrations, although localized degradation due to elevated cadmium and zinc concentrations was documented on the basis of exceedances of probable effects concentrations (PECs). In contrast to impairment determined by exceedances of PECs, equilibrium-partitioning sediment benchmarks (based on simultaneously extracted metals, acid volatile sulfides, and total organic carbon) predict no toxic effects in sediments at the background locations and uncertain toxic effects throughout Pike Hill Brook and the tributary to Cookville Brook, with the exception of the most downstream Cookville Brook location, which indicated no toxic effects. Acute laboratory toxicity testing using the amphipod Hyalella azteca and the midge Chironomus dilutus on pore waters extracted from sediment in situ indicate impairment (based on tests with H. azteca ) at only one location in Pike Hill Brook and no impairment in the tributary to Cookville Brook. Chronic laboratory sediment toxicity testing using H. azteca and C. dilutus indicated toxicity in Pike Hill Brook at several locations in the lower reach and two locations in the tributary to Cookville Brook. Toxicity was not indicated for either species in sediment from the most acidic metal-rich location, likely due to the low lability of copper in that sediment, as indicated by a low proportion of extractable copper (simultaneously extracted metal (SEM) copper only 5 percent of total copper) and due to the flushing of acidic metal-rich pore water from experimental chambers as overlying test water was introduced before and replaced periodically during the toxicity tests. Depositional habitat invertebrate richness and abundance data generally agreed with the results of toxicity tests and with the extent of impact in the watersheds on the basis of sediment and pore waters. The information was used to develop an overall assessment of the impact of mine drainage on the aquatic system downstream from the Pike Hill copper mines. Most of Pike Hill Brook, including several wetland areas that are all downstream from the Eureka and Union mines, was found to be impaired on the basis of water-quality data and biological assessments of fish or benthic invertebrate communities. In contrast, only one location in the tributary to Cookville Brook, downstream from the Smith mine, is definitively impaired. The biological community begins to recover at the most downstream locations in both brooks due to natural attenuation from mixing with unimpaired streams. On the basis of water quality and biological assessment, the reference locations were of good quality. The sediment toxicity, chemistry, and aquatic community survey data suggest that the sediments could be a source of toxicity in Pike Hill Brook and the tributary to Cookville Brook. On the basis of water quality, sediment quality, and biologic communities, the impacts of mine drainage on the aquatic ecosystem health of the watersheds in the study area are generally consistent with the toxicity suggested from laboratory toxicity testing on pore water and sediments.

Vermont↗

USGS2008

Chemical contaminants, health indicators, and reproductive biomarker responses in fish from rivers in the Southeastern United States

Largemouth bass ( Micropterus salmoides ) and common carp ( Cyprinus carpio ) were collected from 13 sites located in the Mobile (MRB), Apalachicola–Flint–Chattahoochee (ARB), Savannah (SRB), and Pee Dee (PRB) River Basins to document spatial trends in accumulative chemical contaminants, health indicators, and reproductive biomarkers. Organochlorine residues, 2,3,7,8-tetrachlorodibenzo- p -dioxin-like activity (TCDD-EQ), and elemental contaminants were measured in composite samples of whole fish, grouped by species and gender, from each site. Mercury (Hg) and polychlorinated biphenyls (PCBs) were the primary contaminants of concern. Concentrations of Hg in bass samples from all basins exceeded toxicity thresholds for piscivorous mammals (> 0.1 μg/g ww), juvenile and adult fish (> 0.2 μg/g ww), and piscivorous birds (> 0.3 μg/g ww). Total PCB concentrations in samples from the MRB, ARB, and PRB were > 480 ng/g ww and may be a risk to piscivorous wildlife. Selenium concentrations also exceeded toxicity thresholds (> 0.75 μg/g ww) in MRB and ARB fish. Concentrations of other formerly used (total chlordanes, dieldrin, endrin, aldrin, mirex, and hexachlorobenzene) and currently used (pentachlorobenzene, pentachloroanisole, dacthal, endosulfan, γ-hexachlorocyclohexane, and methoxychlor) organochlorine residues were generally low or did not exceed toxicity thresholds for fish and piscivorous wildlife. TCDD-EQs exceeded wildlife dietary guidelines (> 5 pg/g ww) in MRB and PRB fish. Hepatic ethoxyresorufin O -deethylase (EROD) activity was generally greatest in MRB bass and carp. Altered fish health indicators and reproductive biomarker were noted in individual fish, but mean responses were similar among basins. The field necropsy and histopathological examination determined that MRB fish were generally in poorer health than those from the other basins, primarily due to parasitic infestations. Tumors were found in few fish ( n = 5; 0.01%); ovarian tumors of smooth muscle origin were found in two ARB carp from the same site. Intersex gonads were identified in 47 male bass (42%) representing 12 sites and may indicate exposure to potential endocrine disrupting compounds. Comparatively high vitellogenin concentrations (> 0.35 mg/mL) in male fish from the MRB, SRB, and PRB indicate exposure to estrogenic or anti-androgenic chemicals.

Science of the Total Environment↗

USGS2016

Vegetation of semi-stable rangeland dunes of the Navajo Nation, Southwestern USA

Dune destabilization and increased mobility is a worldwide issue causing ecological, economic, and health problems for the inhabitants of areas with extensive dune fields. Dunes cover nearly a third of the Navajo Nation within the Colorado Plateau of southwestern USA. There, higher temperatures and prolonged drought beginning in 1996 have produced significant increases in dune mobility. Vegetation plays an important role in dune stabilization, but there are few studies of the plants of the aeolian surfaces of this region. We examined plant species and their attributes within a moderately vegetated dune field of the Navajo Nation to understand the types and characteristics of plants that stabilize rangeland dunes. These dunes supported a low cover of mixed grass-scrubland with fifty-two perennial and annual species including extensive occurrence of non-native annual Salsola spp. Perennial grass richness and shrub cover were positively associated with increased soil sand composition. Taprooted shrubs were more common on sandier substrates. Most dominant grasses had C4 photosynthesis, suggestive of higher water-use efficiencies and growth advantage in warm arid environments. Plant cover was commonly below the threshold of dune stabilization. Increasing sand movement with continued aridity will select for plants adapted to burial, deflation, and abrasion. The study indicates plants tolerant of increased sand mobility and burial but more investigation is needed to identify the plants adapted to establish and regenerate under these conditions. In addition, the role of Salsola spp. in promoting decline of perennial grasses and shrubs needs clarification.

Arizona, Colorado, New Mexico, Utah↗

USGS1996

Detailed study of selenium and other constituents in water, bottom sediment, soil, alfalfa, and biota associated with irrigation drainage in the Uncompahgre Project area and in the Grand Valley, west-central Colorado, 1991-93

In 1985, the U.S. Department of the Interior began a program to study the effects of irrigation drainage in the Western United States. These studies were done to determine whether irrigation drainage was causing problems related to human health, water quality, and fish and wildlife resources. Results of a study in 1991-93 of irrigation drainage associated with the Uncompahgre Project area, located in the lower Gunnison River Basin, and of the Grand Valley, located along the Colorado River, are described in this report. The focus of the report is on the sources, distribution, movement, and fate of selenium in the hydrologic and biological systems and the effects on biota. Generally, other trace- constituent concentrations in water and biota were not elevated or were not at levels of concern. Soils in the Uncompahgre Project area that primarily were derived from Mancos Shale contained the highest concentrations of total and watrer-extractable selenium. Only 5 of 128 alfalfa samples had selenium concentrations that exceeded a recommended dietary limit for livestock. Selenium data for soil and alfalfa indicate that irrigation might be mobilizing and redistributing selenium in the Uncompahgre Project area. Distribution of dissolved selenium in ground water is affected by the aqueous geochemical environment of the shallow ground- water system. Selenium concentrations were as high as 1,300 micrograms per liter in water from shallow wells. The highest concentrations of dissolved selenium were in water from wells completed in alluvium overlying the Mancos Shale of Cretaceous age; selenium concentrations were lower in water from wells completed in Mancos Shale residuum. Selenium in the study area could be mobilized by oxidation of reduced selenium, desorption from aquifer sediments, ion exchange, and dissolution. Infiltration of irrigation water and, perhaps nitrate, provide oxidizing conditions for mobilization of selenium from alluvium and shale residuum and for transport to streams and irrigation drains that are tributary to the Gunnison, Uncompahgre, and Colorado Rivers. Selenium concentrations in about 64 percent of water samples collected from the lower Gunnison River and about 50 percent of samples from the Colorado River near the Colorado-Utah State line exceeded the U.S. Environmental Protection Agency criterion of 5 micrograms per liter for protection of aquatic life. Almost all selenium concentrations in samples collected during the nonirrigation season from Mancos Shale areas exceeded the aquatic-life criterion. The maximum selenium concentrations in surface-water samples were 600 micrograms per liter in the Uncompahgre Project area and 380 micrograms per liter in the Grand Valley. Irrigation drainage from the Uncompahgre Project and the Grand Valley might account for as much as 75 percent of the selenium load in the Colorado River near the Colorado-Utah State line. The primary source areas of selenium were the eastern side of the Uncompahgre Project and the western one-half of the Grand Valley, where there is extensive irrigation on soils derived from Mancos Shale. The largest mean selenium loads from tributary drainages were 14.0 pounds per day from Loutsenhizer Arroyo in the Uncompahgre Project and 12.8 pounds per day from Reed Wash in the Grand Valley. Positive correlations between selenium loads and dissolved-solids loads could indicate that salinity-control projects designed to decrease dissolved-solids loads also could decrease selenium loads from the irrigated areas. Selenium concentrations in irrigation drainage in the Grand Valley were much higher than concentrations predicted by simple evaporative concentration of irrigation source water. Selenium probably is removed from pond water by chemical and biological processes and incorporated into bottom sediment. The maximum selenium concentration in bottom sediment was 47 micrograms per gram from a pond on the eastern side of the Uncompahgre Project.

Water-Resources Investigations Report↗

USGS2009

Water-Quality and Biological Assessment of the Iowa River and Tributaries Within and Contiguous to the Meskwaki Settlement of the Sac and Fox Tribe of the Mississippi in Iowa, 2006-07

In cooperation with the Sac and Fox Tribe of the Mississippi in Iowa (Meskwaki Nation), the U.S. Geological Survey conducted a 2-year baseline assessment of the chemical and biological quality of streams within the Meskwaki Settlement in central Iowa. The Meskwaki Nation is a federally recognized tribe that wishes to establish water-quality standards to safeguard the integrity of surface waters and aquatic biota within the settlement for the health and welfare of the tribal community. The settlement is drained by the Iowa River and four tributaries (Onion, Cattail, Raven, and Bennett Creeks). Water-quality samples were collected at three sites on the Iowa River, two sites on Onion Creek, and one site each on Cattail, Raven, and Bennett Creeks from April 2006 through July 2007. Biological and habitat assessments were conducted at all three sites on the Iowa River and the downstream-most site on Onion Creek from June through August 2007. Analysis of physical properties, major ions, nutrients, trace compounds, bacteria, and total suspended solids in water, and trace metals and organic compounds in streambed sediment provided information about the effects of anthropogenic (human related) activities on the water quality of settlement streams. Analysis of biological samples collected during the summer of 2007, including fish community, benthic macroinvertebrates, and periphyton samples, as well as physical habitat characteristics, provided information on the effects of water quality on the condition of the aquatic environment. The majority of surface water sampled within the settlement was predominately a calcium bicarbonate type. Nitrates (nitrate plus nitrite as nitrogen) exceeded the U.S. Environmental Protection Agency's (USEPA) primary drinking-water Maximum Contaminant Level of 10 ug/L in 19 of 36 samples from sites on the Iowa River and Raven and Bennett Creeks but not in samples from Onion and Cattail Creeks. None of the samples analyzed for pesticides, trace metals, wastewater, or fuel contaminants were found to exceed drinking-water regulations for the USEPA or State of Iowa targeted constituents. Bacteria densities for Escherichia coli (E. coli) ranged from less than 10 to more than 600,000 colony-forming units per 100 milliliters of water and were largest following intense rainfall runoff. The largest densities were recorded in samples collected from the tributaries, most notably from Cattail Creek downstream from the tribal headquarters area and Onion Creek downstream from the sewage lagoons. Arsenic and nickel concentrations in bottom sediment from Onion Creek exceeded the USEPA threshold effects level in a composite sample collected during the habitat assessment in July 2007. Suspended-sediment concentration was estimated in terms of total suspended solids. Overall, Onion and Bennett Creeks were the least turbid, whereas the ephemeral Cattail Creek had the most turbid samples. Aquatic-community data were collected at four sites on the Meskwaki Settlement during the summer of 2007 to provide a baseline biological assessment of stream conditions. This assessment was based on sampling of the fish, benthic macroinvertebrate, and periphyton communities along with physical habitat characteristics. Individual biological metrics were derived from the data collected during the community surveys. These metrics were used to calculate Indexes of Biological Integrity (IBIs). The calculated values from the IBIs provided a numerical value that was used to provide an assessment of the biological condition at each biological sampling site. The fish community samples indicated that all of the sampling sites would be considered in fair condition, with one exception being a collection site on the Iowa River at Highway 49 near Tama, Iowa, which was classified in poor condition. The benthic macroinvertebrate IBI indicated a classification of good for three of the four biological sampling sites, with the Iowa River near Montour, Iowa,

Scientific Investigations Report↗

USGS2016

Contamination with bacterial zoonotic pathogen genes in U.S. streams influenced by varying types of animal agriculture

Animal waste, stream water, and streambed sediment from 19 small (< 32 km 2 ) watersheds in 12 U.S. states having either no major animal agriculture (control, n = 4), or predominantly beef ( n = 4), dairy ( n = 3), swine ( n = 5), or poultry ( n = 3) were tested for: 1) cholesterol, coprostanol, estrone, and fecal indicator bacteria (FIB) concentrations, and 2) shiga-toxin producing and enterotoxigenic Escherichia coli , Salmonella , Campylobacter , and pathogenic and vancomycin-resistant enterococci by polymerase chain reaction (PCR) on enrichments, and/or direct quantitative PCR. Pathogen genes were most frequently detected in dairy wastes, followed by beef, swine and poultry wastes in that order; there was only one detection of an animal-source-specific pathogen gene ( stx1 ) in any water or sediment sample in any control watershed. Post-rainfall pathogen gene numbers in stream water were significantly correlated with FIB, cholesterol and coprostanol concentrations, and were most highly correlated in dairy watershed samples collected from 3 different states. Although collected across multiple states and ecoregions, animal-waste gene profiles were distinctive via discriminant analysis. Stream water gene profiles could also be discriminated by the watershed animal type. Although pathogen genes were not abundant in stream water or streambed samples, PCR on enrichments indicated that many genes were from viable organisms, including several (shiga-toxin producing or enterotoxigenic E. coli , Salmonella , vancomycin-resistant enterococci) that could potentially affect either human or animal health. Pathogen gene numbers and types in stream water samples were influenced most by animal type, by local factors such as whether animals had stream access, and by the amount of local rainfall, and not by studied watershed soil or physical characteristics. Our results indicated that stream water in small agricultural U.S. watersheds was susceptible to pathogen gene inputs under typical agricultural practices and environmental conditions. Pathogen gene profiles may offer the potential to address both source of, and risks associated with, fecal pollution.

Arizona, Indiana, Iowa, Kentucky, Maryland, Michig↗

USGS2020

Development of a suite of functional immune assays and initial assessment of their utility in wild smallmouth bass health assessments

Methods were developed for measuring immune function in Micropterus dolomieu (smallmouth bass). The ultimate objective is to monitor and evaluate changes over time in immune status and disease resistance in conjunction with other characteristics of fish health and environmental stressors. To test these methods for utility in ecotoxicological studies, 192 smallmouth bass, age 2 years and older, were collected from three sites within the Susquehanna River Basin and one site in the Ohio River Basin during spring and fall 2016 and 2017. The anterior kidney was aseptically removed and homogenized for leukocyte isolation. Leukocytes were tested for bactericidal activity against two species of bacteria; respiratory burst activity when stimulated with phorbol 12-myristate 13-acetate; and mitogenesis activity when stimulated with concanavalin A, phytohemagglutinin, and lipopolysaccharide. Tissues were preserved for histopathological analyses. Two of the sites were part of a monitoring program at which surface-water samples were collected monthly (bimonthly in spring) for chemical contaminants. Significant seasonal and (or) site differences in all three immune function tests were observed. Interpretations of seasonal trends in immune function of wild fish or correlations with environmental variables and other factors are difficult to make owing to the complex nature of the immune response and the environment. Differences in immune function could potentially be related to a variety of confounding factors; therefore, additional endpoints and repeated sampling over an extended period are essential to draw conclusions on the immune status of wild fish.

Pennsylvania↗

USGS2018

Contaminants in tropical island streams and their biota

Environmental contamination is problematic for tropical islands due to their typically dense human populations and competing land and water uses. The Caribbean island of Puerto Rico (USA) has a long history of anthropogenic chemical use, and its human population density is among the highest globally, providing a model environment to study contaminant impacts on tropical island stream ecosystems. Polycyclic Aromatic Hydrocarbons, historic-use chlorinated pesticides, current-use pesticides, Polychlorinated Biphenyls (PCBs), and metals (mercury, cadmium, copper, lead, nickel, zinc, and selenium) were quantified in the habitat and biota of Puerto Rico streams and assessed in relation to land-use patterns and toxicological thresholds. Water, sediment, and native fish and shrimp species were sampled in 13 rivers spanning broad watershed land-use characteristics during 2009–2010. Contrary to expectations, freshwater stream ecosystems in Puerto Rico were not severely polluted, likely due to frequent flushing flows and reduced deposition associated with recurring flood events. Notable exceptions of contamination were nickel in sediment within three agricultural watersheds (range 123–336 ppm dry weight) and organic contaminants (PCBs, organochlorine pesticides) and mercury in urban landscapes. At an urban site, PCBs i n several fish species (Mountain Mullet Agonostomus monticola [range 0.019–0.030 ppm wet weight] and American Eel Anguilla rostrata [0.019–0.031 ppm wet weight]) may pose human health hazards, with concentrations exceeding the U.S. Environmental Protection Agency (EPA) consumption limit for 1 meal/month. American Eel at the urban site also contained dieldrin (range < detection-0.024 ppm wet weight) that exceeded the EPA maximum allowable consumption limit. The Bigmouth Sleeper Gobiomorous dormitor , an important piscivorus sport fish, accumulated low levels of organic contaminants in edible muscle tissue (due to its low lipid c ontent) and may be most suitable for human consumption island-wide; only mercury at one site (an urban location) exceeded EPA's consumption limit of 3 meals/month for this species. These results comprise the first comprehensive island-wide contaminant assessment of Puerto Rico streams and biota and provide natural resource and public health agencies here and in similar tropical islands elsewhere with information needed to guide ecosystem and fisheries conservation and management and human health risk assessment.

Environmental Research↗