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USGS2002

Snow chemistry of the Cascade-Sierra Nevada Mountains

This investigation assesses geographic variations in atmospheric deposition in Washington, Oregon, and California using snow cores from the Cascade-Sierra Nevada Mountains, collected from late February to mid-March 1983. A statistical analysis of the analytical and sampling precision was made. The snowpack in the higher Cascades and Sierra Nevada is not strongly influenced by anthropogenic activities at present. The pH of snow samples ranges from 5.11 to 5.88. Sulfate and nitrate correlate with H+ in some segments of the sample traverse. The SO4 data show apparent influence from major source areas in Washington and California; nitrate does not. An apparent decrease in NH4 in snow in Washington and California suggests atmospheric interactions resulting in the removal of NH4. The NH4 reduction raises questions about nutrient supply to the mountain vegetation. Heavy-metal correlations included Cd, Cu, and Fe with Pb, and Mn with K and DOC, among others. No correlation was found between constituents and snow-water content.

California, Oregon, Washington↗

USGS2002

Relations of benthic macroinvertebrates to concentrations of trace elements in water, streambed sediments, and transplanted bryophytes and stream habitat conditions in nonmining and mining areas of the upper Colorado River basin, Colorado, 1995-98

Intensive mining activity and highly mineralized rock formations have had significant impacts on surface-water and streambed-sediment quality and aquatic life within the upper reaches of the Uncompahgre River in western Colorado. A synoptic study by the U.S. Geological Survey National Water-Quality Assessment Program was completed in the upper Uncompahgre River Basin in 1998 to better understand the relations of trace elements (with emphasis on aluminum, arsenic, copper, iron, lead, and zinc concentrations) in water, streambed sediment, and aquatic life. Water-chemistry, streambed-sediment, and benthic macroinvertebrate samples were collected during low-flow conditions between October 1995 and July 1998 at five sites on the upper Uncompahgre River, all downstream from historical mining, and at three sites in drainage basins of the Upper Colorado River where mining has not occurred. Aquatic bryophytes were transplanted to all sites for 15 days of exposure to the water column during which time field parameters were measured and chemical water-quality and benthic macroinvertebrate samples were collected. Stream habitat characteristics also were documented at each site. Certain attributes of surface-water chemistry among streams were significantly different. Concentrations of total aluminum, copper, iron, lead, and zinc in the water column and concentrations of dissolved aluminum, copper, and zinc were significantly different between nonmining and mining sites. Some sites associated with mining exceeded Colorado acute aquatic-life standards for aluminum, copper, and zinc and exceeded Colorado chronic aquatic-life standards for aluminum, copper, iron, lead, and zinc. Concentrations of copper, lead, and zinc in streambed sediments were significantly different between nonmining and mining sites. Generally, concentrations of arsenic, copper, lead, and zinc in streambed sediments at mining sites exceeded the Canadian Sediment Quality Guidelines probable effect level (PEL), except at two mining sites where concentrations of copper and zinc were below the PEL. Concentrations of arsenic, copper, iron, and lead in transplanted bryophytes were significantly different between nonmining and mining sites. Bioconcentration factors calculated for 15-day exposure using one-half of the minimum reporting level were significantly different between nonmining and mining sites. In general, concentrations of trace elements in streambed sediment and transplanted bryophytes were more closely correlated than were the concentrations of trace elements in the water column with streambed sediments or concentrations in the water column with transplanted bryophytes. Stream habitat was rated as optimal to suboptimal using the U.S. Environmental Protection Agency Rapid Bioassessment Protocols for all sites in the study area. Generally, stream habitat conditions were similar at nonmining compared to mining sites and were suitable for diverse macroinvertebrate communities. All study sites had optimal instream habitat except two mining sites with suboptimal instream habitat because of disturbances in stream habitat. The benthic macroinvertebrate community composition at nonmining sites and mining sites differed. Mining sites had significantly lower total abundance of macroinvertebrates, fewer numbers of taxa, and lower dominance of Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies), and a larger percentage of tolerant species than did nonmining sites. The predominance of Baetis sp. (mayflies), Hydropsychidae (caddisflies), and large percentage of Orthocladiinae chironomids (midges) at mining sites indicated that these species may be tolerant to elevated trace-element concentrations. The absence of Heptageniidae (mayflies), Chloroperlidae (stoneflies), and Rhyacophila sp. (caddisflies) at mining sites indicated that these species may be sensitive to elevated trace-element concentrations. Comparison of field parameters and chemical water-quality characteristics to biological conditions was conducted using a water quality score (WQS) and a biological condition score (BCS). In general, as the WQS increased, the BCS also increased. Nonmining sites had higher WQS's and BCS's than mining sites. The BCS categorized the nonmining sites as nonimpaired, and the mining sites were categorized as slightly to severely impaired. Other important factors in this study that influenced surface-water quality include stream pH, chemical solubility of trace elements, stream temperature, stream elevation, organic inputs into the stream, basin geology, and stream habitat at a site. Although high concentrations of some trace elements may occur naturally, trace-element concentrations at mining sites were much higher. High trace-element concentrations appear to affect the macroinvertebrate communities more than the other factors at these sites. Mayfly, stonefly, and caddisfly abundance and the percentage of midge species are good indicators of mining effects at sites in the study area.

Colorado↗

USGS2011

Simultaneous speciation of arsenic, selenium, and chromium: species, stability, sample preservation, and analysis of ash and soil leachates

An analytical method using high-performance liquid chromatography separation with inductively coupled plasma mass spectrometry (ICP-MS) detection previously developed for the determination of Cr(III) and Cr(VI) has been adapted to allow the determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) under the same chromatographic conditions. Using this method, all six inorganic species can be determined in less than 3 min. A dynamic reaction cell (DRC)-ICP-MS system was used to detect the species eluted from the chromatographic column in order to reduce interferences. A variety of reaction cell gases and conditions may be utilized with the DRC-ICP-MS, and final selection of conditions is determined by data quality objectives. Results indicated all starting standards, reagents, and sample vials should be thoroughly tested for contamination. Tests on species stability indicated that refrigeration at 10° C was preferential to freezing for most species, particularly when all species were present, and that sample solutions and extracts should be analyzed as soon as possible to eliminate species instability and interconversion effects. A variety of environmental and geological samples, including waters and deionized water [leachates] and simulated biological leachates from soils and wildfire ashes have been analyzed using this method. Analytical spikes performed on each sample were used to evaluate data quality. Speciation analyses were conducted on deionized water leachates and simulated lung fluid leachates of ash and soils impacted by wildfires. These results show that, for leachates containing high levels of total Cr, the majority of the chromium was present in the hexavalent Cr(VI) form. In general, total and hexavalent chromium levels for samples taken from burned residential areas were higher than those obtained from non-residential forested areas. Arsenic, when found, was generally in the more oxidized As(V) form. Selenium (IV) and (VI) were present, but typically at low levels.

Analytical and Bioanalytical Chemistry↗

USGS2015

Estuarine bed-sediment-quality data collected in New Jersey and New York after Hurricane Sandy, 2013

This report describes a reconnaissance study of estuarine bed-sediment quality conducted June–October 2013 in New Jersey and New York after Hurricane Sandy in October 2012 to assess the extent of contamination and the potential long-term human and ecological impacts of the storm. The study, funded through the Disaster Relief Appropriations Act of 2013 (PL 113-2), was conducted by the U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency and the National Oceanographic and Atmospheric Administration. In addition to presenting the bed-sediment-quality data, the report describes the study design, documents the methods of sample collection and analysis, and discusses the steps taken to assure the quality of the data. Bed-sediment samples were collected from June to October 2013 from 167 estuarine sites extending from Cape May, New Jersey, to the New York Harbor and the eastern end of Long Island. Each sampling location and study region was characterized by using geographic information to identify potential contaminant sources. Characterizations included land cover, locations and types of businesses (industrial, financial, and others), spills (sewage, chemical, and others), bulk storage facilities, effluent discharges within 2 kilometers of the sampling point, and discharges within inundated and non-inundated regions near the sampling location. Samples were analyzed for particle size, total organic carbon, metals and trace elements, semivolatile organic compounds, wastewater compounds, hormones, and sediment toxicity. Samples were also screened using x-ray fluorescence, Fourier transform infrared spectroscopy, and x-ray diffraction. In addition, bioassays for endocrine disruptors and protein phosphatase 2A inhibition were conducted. The study was designed to provide the data needed to understand the extent and sources of contamination resulting from Hurricane Sandy, to compare the chemistry and toxicity of estuarine bed sediments before and after the storm, and to evaluate the usefulness of rapid screening and bioassay approaches in disaster settings.

New Jersey, New York↗

USGS2022

Environmental geochemistry of an epigenetic Pb-Zn-Ag deposit at the abandoned Cecilia mine, Puno region, Peru

The abandoned Cecilia Pb-Zn-Ag mine is located at the headwaters of the Lake Titicaca watershed in the Altiplano of Peru. The site is characterized by three months of high precipitation and nine months of limited precipitation. The environmental geochemical characterization of the abandoned mine was done to evaluate environmental risks at the site from mine wastes and mine drainage, and their potential for downstream impacts on water quality in Lake Titicaca. The approach included sampling of mine waste, water, and sediment. Composite mine waste samples were collected from six main piles (four tailings, two waste rock). The surface water was collected from (1) drainage from mine portals; (2) the Cecilia and Crucero rivers upstream of mine influences; (3) the impacted reach of the Cecilia River down to its confluence with the Crucero River; and (4) the Crucero River, which receives drainage from the Cecilia River. Sampling in the dry season did not identify seeps from the waste rock or tailings piles. This study documents the capacity of the site to generate acid mine drainage from the mine waste and underground workings. Mine waste has elevated concentrations of As (up to 883 mg/kg), Cu (up to 20,106 mg/kg), Pb (up to 16,716 mg/kg), and Zn (up to 11,937 mg/kg). Results for dissolved concentrations from leaching experiments on mine waste samples showed high leachability for As (0.001 to 0.95 mg/L), Cu (0.01 to 57.34 mg/L), Cd (0.001 to 1.13 mg/L), Fe (0.42 to 785 mg/L), Zn (0.01 to 91 mg/L), and Mn (0.05 to 279 mg/L) with an acidic pH (2.5 to 6.0). Water chemistry at the site varied on the basis of water type. The Cecilia and Crucero rivers had neutral pH and low concentrations of metals upstream of mine influences. In contrast, samples collected at the mine portal were highly acidic (pH 1.4 to 3.7) with high dissolved concentrations of Fe (up to 4,720 mg/L), Al (up to 400 mg/L), sulfate (up to 19,428 mg/L), As (up to 5.92 mg/L), Cd (up to 9.84 mg/L), Cu (up to 1.56 mg/L), Pb (up to 1.95 mg/L), and Zn (up to 4,065 mg/L), causing an increase in metal concentrations in the river downstream after mixing. Carbonate rocks in the watershed produce alkaline waters that neutralize acid drainage prior to its confluence with the Crucero River. Proposed remediation methods include capping mine waste to limit contact with rainwater and passive treatment of mine portal drainage.

Cecilia mine↗

USGS2014

An evaluation of the toxicity of contaminated sediments from Waukegan Harbor, Illinois, following remediation

Waukegan Harbor in Illinois was designated as a Great Lakes Area of Concern due to high concentrations of sediment-associated polychlorinated biphenyls (PCBs). The objective of this study was to evaluate the toxicity of 20 sediment samples collected after remediation (primarily dredging) of Waukegan Harbor for PCBs. A 42-day whole sediment toxicity test with the amphipod Hyalella azteca (28-day sediment exposure followed by a 14-day reproductive phase) and sediment toxicity tests with Microtox® were conducted to evaluate sediments from Waukegan Harbor. Endpoints measured were survival, growth, and reproduction (amphipods) and luminescent light emission (bacteria). Survival of amphipods was significantly reduced in 6 of the 20 sediment samples relative to the control. Growth of amphipods (either length or weight) was significantly reduced relative to the control in all samples. However, reproduction of amphipods identified only two samples as toxic relative to the control. The Microtox basic test, conducted with organic extracts of sediments identified only one site as toxic. In contrast, the Microtox solid-phase test identified about 50% of the samples as toxic. A significant negative correlation was observed between reproduction and the concentration of three polynuclear aromatic hydrocarbons (PAHs) normalized to total organic carbon. Sediment chemistry and toxicity data were evaluated using sediment quality guidelines (consensus-based probable effect concentrations, PECs). Results of these analyses indicate that sediment samples from Waukegan Harbor were toxic to H. azteca contaminated at similar contaminant concentrations as sediment samples that were toxic to H. azteca from other areas of the United States. The relationship between PECs and the observed toxicity was not as strong for the Microtox test. The results of this study indicate that the first phase of sediment remediation in Waukegan Harbor successfully lowered concentrations of PCBs at the site. Though the sediments were generally not lethal, there were still sublethal effects of contaminants in sediments at this site observed on amphipods in long-term exposures (associated with elevated concentrations of metals, PCBs, and PAHs).

Archives of Environmental Contamination and Toxico↗

USGS1999

Stable lead isotopic analyses of historic and contemporary lead contamination of San Francisco Bay estuary

Variations in stable lead isotopic composition (240Pb, 206Pb, 207Pb, 208Pb) in three sediment cores from the San Francisco Bay estuary document temporal changes in sources of lead during the past two centuries. Sediment, with lead from natural geologic sources, and relatively homogeneous lead isotopic compositions are overlain by sediments whose isotopic compositions indicate change in the sources of lead associated with anthropogenic modification of the estuary. The first perturbations of lead isotopic composition in the cores occur in the late 1800s concordant with the beginning of industrialization around the estuary. Large isotopic shifts, toward lower 206Pb/207Pb, occur after the turn of the century in both Richardson and San Pablo Bays. A similar relationship among lead isotopic compositions and lead concentrations in both Bays suggest contamination from the same source (a lead smelter). The uppermost sediments (post 1980) of all cores also have a relatively homogenous lead isotopic composition distinct from pre-anthropogenic and recent aerosol signatures. Lead isotopic compositions of leachates from fourteen surface sediments and five marsh samples from the estuary were also analyzed. These analyses suggest that the lead isotopic signature identified in the upper horizons of the cores is spatially homogeneous among recently deposited sediments throughout the estuary. Current aerosol lead isotopic compositions [Smith, D.R., Niemeyer, S., Flegal, A.R., 1992. Lead sources to California sea otters: industrial inputs circumvent natural lead biodepletion mechanisms. Environmental Research 57, 163-175] are distinct from the isotopic compositions of the surface sediments, suggesting that the major source of lead is cycling of historically contaminated sediments back through the water column. Both the upper core sediments and surface sediments apparently derive their lead predominantly from sources internal to the estuary. These results support the idea that geochemical cycling of lead between sediments and water accounts for persistently elevated lead concentrations in the water column despite 10-fold reduction of external source inputs to San Francisco Bay [Flegal, A.R., Rivera-Duarte, I., Ritson, P.I., Scelfo, G., Smith, G.J., Gordon, M., Sanudo-Wilhelmy, S.A., 1996. Metal contamination in San Francisco Waters: historic perturbations, contemporary concentrations, and future considerations in San Francisco Bay. In: Hollobaugh, J.T. (Ed.), The Ecosystem. AAAS, pp. 173-188].

California↗

USGS2023

Arsenic, chromium, uranium, and vanadium in rock, alluvium, and groundwater, Mojave River and Morongo Areas, western Mojave Desert, southern California

Trace elements within groundwater that originate from aquifer materials and pose potential public-health hazards if consumed are known as geogenic contaminants. The geogenic contaminants arsenic, chromium, and vanadium can form negatively charged ions with oxygen known as oxyanions. Uranium complexes with bicarbonate and carbonate to form negatively charged ions having aqueous chemistry similar to oxyanions. The concentrations of arsenic, chromium, uranium, and vanadium in groundwater result from the combined effects of (1) geologic abundance within aquifer materials; (2) the fraction of these elements that have weathered from and sorbed to the surfaces of mineral grains and are potentially available to groundwater; and (3) the aqueous chemistry of dissolved oxyanions in groundwater during different redox conditions and pH, both of which are affected by hydrogeology, including the length of time groundwater has been in contact with aquifer materials. Concentrations of arsenic, chromium, uranium, and vanadium were measured in samples of (1) rock, surficial alluvium, and drill cuttings using portable (handheld) X-ray fluorescence (pXRF); (2) operationally defined fractions extractable from these materials; and (3) water from wells sampled between 2000 and 2018 within the 3,500 square mile Mojave River area and Morongo area of the western Mojave Desert, southern California. Regionally, rock and surficial alluvium in the Mojave River and Morongo areas are high in arsenic, low in chromium and uranium, and near the average bulk continental crust concentration for vanadium. Locally, high chromium concentrations are present in mafic rock within the San Gabriel Mountains; high uranium concentrations are present in felsic rock within the San Bernardino Mountains; and high arsenic, uranium, and vanadium concentrations are present in extrusive (volcanic) felsic rock within uplands surrounding groundwater basins along the Mojave River downstream from Barstow, California. Elemental assemblages identified using principal component analyses (PCA) of pXRF data were used to characterize felsic, mafic, and felsic volcanic source terranes in rock, surficial alluvium, and in geologic material penetrated by selected monitoring wells drilled between 1994 and 2018. Highly felsic alluvium associated with recent deposition from the Mojave River was identified along the 90-mile length of the floodplain aquifer along the river. The thickness of these highly felsic alluvial deposits ranged from 200 feet (ft) near Victorville and near Barstow to a thin veneer about 30 ft thick downstream from Victorville and downstream portions of the floodplain aquifer within the Mojave Valley. Groundwater in the Mojave River and Morongo areas was generally oxic and alkaline (pH≥7.5). Maximum concentrations of arsenic, hexavalent chromium [Cr(VI)], uranium, and vanadium in water from as many as 498 wells sampled between 2000 and 2018 were 360, 140, 1,470, and 690 micrograms per liter (μg/L), respectively. Water from 22 percent of sampled wells exceeded the U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) for arsenic of 10 μg/L, with arsenic concentrations commonly exceeding the MCL in water from wells east of Barstow, deep wells in the Victorville fan, and in suboxic or reduced groundwater within the floodplain aquifer. Water from about 1 percent of sampled wells had Cr(VI) concentrations greater than the California MCL for total chromium of 50 μg/L, whereas 13 percent of sampled wells had Cr(VI) concentrations greater than the former California MCL of 10 μg/L. Hexavalent chromium concentrations were highest in water from wells in the Sheep Creek alluvial fan, eroded from mafic rock in the San Gabriel Mountains, although Cr(VI) concentrations greater than the former California MCL also were present elsewhere in the study area where mafic materials or older groundwater were present. Water from about 9 percent of sampled wells exceeded the EPA MCL for uranium of 30 μg/L, with concentrations exceeding the MCL commonly associated with irrigation return from agricultural land overlying the floodplain aquifer. Water from about 7 percent of sampled wells had vanadium concentrations greater than the California notification level of 50 μg/L; most of these wells were in the Victorville fan within the Mojave River area. In general, arsenic concentrations were higher in suboxic or reduced water; chromium concentrations were higher in oxic, alkaline (pH≥7.5) water; uranium concentrations were higher in circumneutral to slightly alkaline water (pH≤7.4); and vanadium concentrations were higher in highly alkaline (pH≥8.0) water, independent of redox status. Concentrations within geologic source terranes are not the sole factor controlling the concentrations of geogenic elements in groundwater. Differences in mineral weathering, pH-dependent sorption to surface-exchange sites on mineral grains, and aqueous geochemistry (especially redox status and pH) affect geogenic element concentrations in groundwater. Consequently, the relative abundances of arsenic, Cr(VI), uranium, and vanadium in groundwater differ from their relative abundances in the average bulk continental crust and their regional abundances in rock and surficial alluvium within groundwater basins of the western Mojave Desert. Processes that control the concentrations of arsenic, chromium, uranium, and vanadium in groundwater operate at the mineral-grain and aquifer scale. At the mineral-grain scale, sequential chemical extraction data show arsenic and uranium are more available to groundwater (under specific geochemical conditions) than chromium or vanadium, which largely are unavailable within unweathered mineral grains. Additionally, chromium and vanadium form few aqueous complexes and bind tightly with iron minerals within surface coatings on mineral grains making them less available to groundwater, whereas complexation with other dissolved ions enhances the solubility of uranium and, to a lesser extent, arsenic. Complexation also increases the valence (less negative charge) and increases the size of dissolved oxyanions and uranium complexes with bicarbonate and carbonate making them less readily sorbed to aquifer materials. At the aquifer scale, hydrogeology (including isolation of water in aquifers from surface sources of recharge, older groundwater age, and long contact times between groundwater and aquifer materials) combined with geochemical processes (such as silicate weathering) to produce alkaline groundwater. Desorption from sorption sites on the surfaces of mineral grains with increasing pH increases arsenic, chromium, and vanadium concentrations in water from wells and increases Cr(VI) concentrations as long as water remains oxic. Aqueous geochemistry and concentrations of geogenic contaminants also are affected by anthropogenic activities including (1) discharge of treated municipal wastewater, which may change the redox status of groundwater; (2) return from irrigated agriculture, which may alter the chemistry of groundwater and increase the solubility of trace elements such as uranium; and (3) groundwater pumping and subsequent water-level declines, which may change the source of water yielded by wells. The quality of water imported from northern California and infiltrated from ponds for groundwater recharge may be altered by naturally present trace elements, especially uranium in areas of agricultural land use or chromium within mafic alluvium.

California↗

USGS2004

Combination of LC/TOF-MS and LC/Ion Trap MS/MS for the Identification of Diphenhydramine in Sediment Samples

Diphenhydramine (Benadryl) is a popular over-the-counter antihistaminic medication used for the treatment of allergies. After consumption, excretion, and subsequent discharge from wastewater treatment plants, it is possible that diphenhydramine will be found in environmental sediments due to its hydrophobicity (log P = 3.27). This work describes a methodology for the first unequivocal determination of diphenhydramine bound to environmental sediments. The drug is removed from the sediments by accelerated solvent extraction and then analyzed by liquid chromatography with a time-of-flight mass spectrometer and an ion trap mass spectrometer. This combination of techniques provided unequivocal identification and confirmation of diphenhydramine in two sediment samples. The accurate mass measurements of the protonated molecules were m/z 256.1703 and 256.1696 compared to the calculated mass of m/z 256.1701, resulting in errors of 0.8 and 2.3 ppm. This mass accuracy was sufficient to verify the elemental composition of diphenhydramine in each sample. Furthermore, accurate mass measurements of the primary fragment ion were obtained. This work is the first application of time-of-flight mass spectrometry for the identification of diphenhydramine and shows the accumulation of an over-the-counter medication in aquatic sediments at five different locations.

Analytical Chemistry↗

USGS2000

Stormflow chemistry in the Santa Ana River below Prado Dam and at the diversion downstream from Imperial Highway, southern California, 1995-98

The Santa Ana River drains about 2,670 square miles of the densely populated coastal area of southern California, near Los Angeles. Almost all the flow in the river, more than 200,000 acre-feet annually, is diverted into ponds where it infiltrates and recharges underlying aquifers. About 2 million people are dependent on these aquifers for water supply. Stormflow in the Santa Ana River is considered a source of "high-quality" water suitable for use as a source of ground-water recharge. To test this assumption, stormflow samples were collected at two locations--below Prado Dam and at the diversion point downstream from Imperial Highway--for 12 winter storms between 1995 and 1998. Nitrate concentrations decreased during stormflow from a median concentration of 7.8 milligrams per liter in base flow to concentrations less than 1 milligram per liter in some large storms. Concentrations of chemically reduced forms of nitrogen (nitrite, ammonia, and organic nitrogen) increased during stormflow and are the predominant forms of nitrogen in large stormflows. Dissolved organic carbon (DOC) concentrations increased from a median concentration of 4.6 milligrams per liter in base flow to more than 20 milligrams per liter in some stormflows. Concentrations of DOC were especially high during the first storm of the rainy season, and large increases in DOC concentrations were measured even as a result of small early season storms that did not cause large increases in streamflow. DOC present during early season stormflow had less ultraviolet absorbance at 254 nanometers (UV 254 ) per unit of carbon than did DOC from late season stormflows. DOC in water held in storage behind Prado Dam had the highest UV 254 absorbance per unit of carbon. Maximum pesticide concentrations in stormflow did not exceed U.S. Environmental Protection Agency Maximum Contaminant Levels. Most pesticide concentrations were less than 1 microgram per liter and less than the detection limits obtained using standard drinking water analyses. Increases in concentrations of pesticides such as diazinon, malathion, and chlorpyrifos in stormflow result from runoff from urban areas downstream from Prado Dam. In general, large late season stormflows have the most pesticide detections of all stormflows sampled. Concentrations of methyl tert-butyl ether (MTBE), a gasoline additive, during base flow were as high as 0.9 microgram per liter and concentrations decreased during stormflow. Like pesticides, the concentrations did not exceed the U.S. Environmental Protection Agency Maximum Contaminant Levels for MTBE.

California↗

USGS2004

Dissolved pesticide and organic carbon concentrations detected in surface waters, northern Central Valley, California, 2001-2002

Field and laboratory studies were conducted to determine the effects of pesticide mixtures on Chinook salmon under various environmental conditions in surface waters of the northern Central Valley of California. This project was a collaborative effort between the U.S. Geological Survey (USGS) and the University of California. The project focused on understanding the environmental factors that influence the toxicity of pesticides to juvenile salmon and their prey. During the periods January through March 2001 and January through May 2002, water samples were collected at eight surface water sites in the northern Central Valley of California and analyzed by the USGS for dissolved pesticide and dissolved organic carbon concentrations. Water samples were also collected by the USGS at the same sites for aquatic toxicity testing by the Aquatic Toxicity Laboratory at the University of California Davis; however, presentation of the results of these toxicity tests is beyond the scope of this report. Samples were collected to characterize dissolved pesticide and dissolved organic carbon concentrations, and aquatic toxicity, associated with winter storm runoff concurrent with winter run Chinook salmon out-migration. Sites were selected that represented the primary habitat of juvenile Chinook salmon and included major tributaries within the Sacramento and San Joaquin River Basins and the Sacramento?San Joaquin Delta. Water samples were collected daily for a period of seven days during two winter storm events in each year. Additional samples were collected weekly during January through April or May in both years. Concentrations of 31 currently used pesticides were measured in filtered water samples using solid-phase extraction and gas chromatography-mass spectrometry at the U.S. Geological Survey's organic chemistry laboratory in Sacramento, California. Dissolved organic carbon concentrations were analyzed in filtered water samples using a Shimadzu TOC-5000A total organic carbon analyzer.

California↗

USGS1997

Physical and chemical characteristics of Terrace Reservoir, Conejos County, Colorado, May 1994 through May 1995

Terrace Reservoir receives drainage of low-pH, metal-enriched water from mineralized areas, including the Summitville Mine, within the Alamosa River Basin. Drainage from the Summitville Mine has contributed a substantial part of the metal load to Terrace Reservoir. From May 1994 through May 1995, a study was done by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to evaluate the physical and chemical characteristics of Terrace Reservoir. Terrace Reservoir was thermally stratified from about mid-May through August 1994. Thermal stratification was absent from September\x111994through March 1995. During periods of stratification, underflow of the Alamosa River was predominant, and residence times of the underflow were shortened by 40 to 75\x11percent of the theoretical residence times for a well-mixed reservoir. Transport and deposition of suspended solids in Terrace Reservoir varied spatially and temporally. Most of the suspended solids were deposited in Terrace Reservoir. The concentration of dissolved oxygen in the reservoir varied little spatially or temporally and generally was within a few tenths of the dissolved-oxygen concentration of the inflow. The pH of water in the reservoir generally ranged from about 4.0 to about 7.0, depending on date, depth, and location. The largest pH values were measured during May. A markeddecrease of about 1.5\x11pH units occurred at site T5 in the reservoir about mid-June. The pH of the reservoir remained at or below 5.5 from mid-June through November. Dissolved-metal concentrations varied spatially and temporally in response to several factors, which included inflow characteristics, reservoir stratification and mixing, inflow-routing and flow-through patterns, residence times, sedimentation, dissolved oxygen, and pH.Inflow chemistry is the dominant controlling factor of metal chemistry within Terrace Reservoir.During periods of stratification, large vertical variations in metal concentrations occurred. The highest metal concentrations in the reservoir generally were measured in the hypolimnion between June and August. During June, epilimnetic water of the reservoir had pH values greater than 6.0, and metal concentrations were lower than hypolimnetic concentrations. In the hypolimnion, pH values were less than 5.5. The difference between the chemistry of the epilimnion and the hypolimnion was due to differences in flow routing and residence times of water in those respective layers. The dissolved-metal concentrations were larger during July and August than during June.During September, small vertical variations in metalconcentrations occurred, and the dissolved-metal concentrations were nearly equivalent to the average August metal concentrations, indicatingthat the metal concentrations measured during September resulted largely from reservoir mixing.During March, the largest metal concentrationsoccurred in the epilimnion, where pH was about 5.5; in the hypolimnion, where the pH was about 6.0, dissolved-metal concentrations were substantially lower and reflected inflow concentrations.

Colorado↗

USGS2015

Suburban groundwater quality as influenced by turfgrass and septic sources, Delmarva Peninsula, USA

Suburban land use is expanding in many parts of the United States and there is a need to better understand the potential water-quality impacts of this change. This study characterized groundwater quality in a sandy, water-table aquifer influenced by suburban development and compared the results to known patterns in water chemistry associated with natural, background conditions and agricultural effects. Samples for nutrients, major ions, and isotopes of N and O in NO 3 − were collected in 2011 beneath turfgrass from 29 shallow wells (median depth 3.7 m) and from 18 deeper wells (median depth 16.9 m) in a long-term suburban development. Nitrate (as N) concentrations in groundwater beneath turfgrass were highly variable (0.02–22.3 mg L −1 ) with a median of 2.7 mg L −1 , which is higher than natural water chemistry (>0.4 mg L −1 ; Na + –Cl − –HCO 3 − water type), but significantly lower than concentrations beneath a nearby agricultural area (median 16.9 mg L −1 ; p < .0001). Dissolved Fe concentrations in shallow suburban groundwater, attributed to chelated Fe in turfgrass fertilizers, were significantly higher ( p < .005) than concentrations from the agricultural site, although a Ca 2+ –Mg 2+ –Cl − –NO 3 − water type was dominant in both areas. A Na + –Cl − –NO 3 − water type indicated a septic-system source for nitrate in deep suburban groundwater (0.06–6.0 mg L −1 ; median 1.5 mg L −1 ). Isotopic data indicated denitrification; however, geochemical techniques were more helpful in identifying nitrate sources. Results indicate that suburban expansion into agricultural areas may significantly decrease overall nitrate concentrations in groundwater, but excessive turfgrass fertilization could result in localized contamination.

Delaware↗

USGS1996

Physical and chemical characteristics of Terrace Reservoir, Conejos County, Colorado, May 1994 through May 1995; interim report

Terrace Reservoir receives drainage of low-pH, metal-enriched water from mineralized areas, including the Summitville Mine, within the Alamosa River Basin. Drainage from the Summitville Mine has contributed a substantial part of the metal load to Terrace Reservoir. From May 1994 through May 1995, a study was done by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to evaluate the physical and chemical characteristics of Terrace Reservoir. Terrace Reservoir was thermally stratified from about mid-May through August 1994. Thermal stratification was absent from September\x111994through March 1995. During periods of stratification, underflow of the Alamosa River was predominant, and residence times of the underflow were shortened by 40 to 75\x11percent of the theoretical residence times for a well-mixed reservoir. Transport and deposition of suspended solids in Terrace Reservoir varied spatially and temporally. Most of the suspended solids were deposited in Terrace Reservoir. The concentration of dissolved oxygen in the reservoir varied little spatially or temporally and generally was within a few tenths of the dissolved-oxygen concentration of the inflow. The pH of water in the reservoir generally ranged from about 4.0 to about 7.0, depending on date, depth, and location. The largest pH values were measured during May. A markeddecrease of about 1.5\x11pH units occurred at site T5 in the reservoir about mid-June. The pH of the reservoir remained at or below 5.5 from mid-June through November. Dissolved-metal concentrations varied spatially and temporally in response to several factors, which included inflow characteristics, reservoir stratification and mixing, inflow-routing and flow-through patterns, residence times, sedimentation, dissolved oxygen, and pH. Inflow chemistry is the dominant controlling factor of metal chemistry within Terrace Reservoir. During periods of stratification, large vertical variations in metal concentrations occurred. The highest metal concentrations in the reservoir generally were measured in the hypolimnion between June and August. During June, epilimnetic water of the reservoir had pH values greater than 6.0, and metal concentrations were lower than hypolimnetic concentrations. In the hypolimnion, pH values were less than 5.5. The difference between the chemistry of the epilimnion and the hypolimnion was due to differences in flow routing and residence times of water in those respective layers. The dissolved-metal concentrations were larger during July and August than during June. During September, small vertical variations in metal concentrations occurred, and the dissolved-metal concentrations were nearly equivalent to the average August metal concentrations, indicatingthat the metal concentrations measured during September resulted largely from reservoir mixing.During March, the largest metal concentrationsoccurred in the epilimnion, where pH was about 5.5; in the hypolimnion, where the pH was about 6.0, dissolved-metal concentrations were substantially lower and reflected inflow concentrations.

Colorado↗

USGS2000

Properties and potential environmental applications of carbon adsorbents from waste tire rubber

The properties of tire-derived carbon adsorbents (TDCA) produced from select tire chars were compared with those derived from an Illinois coal and pistachio nut shells. Chemical analyses of the TDCA indicated that these materials contain metallic elements not present in coal-and nut shell-derived carbons. These metals, introduced during the production of tire rubber, potentially catalyze steam gasification reactions of tire char. TDCA carbons contained larger meso-and macopore volumes than their counterparts derived from coal and nut shell (on the moisture-and ash-free-basis). Adsorptive properties of the tire-derived adsorbent carbons for air separation, gas storage, and gas clean up were also evaluated and compared with those of the coal-and nut shell derived carbons as well as a commercial activated carbon. The results revealed that TDCA carbons are suitable adsorbents for removing vapor-phase mercury from combustion flue gases and hazardous organic compounds from industrial gas streams.

ACS Division of Fuel Chemistry, Preprints↗

USGS2000

A hydrologic primer for New Jersey watershed management

The U.S. Geological Survey (USGS) and the N.J. Department of Environmental Protection (NJDEP), and many other agencies and organizations are striving to educate the public about New Jersey’s water resources. In 1996, the NJDEP began implementing a “watershed management approach” to maintain the physical, chemical, and biological integrity of New Jersey’s waters. This approach concentrates on managing individual watershed areas by (1) defining the physical geographic boundaries of the watersheds, (2) basing water policy on sound scientific principles, and (3) developing partnerships with the public--the people most affected by watershed-management policies. New Jersey can be divided into five water regions as defined by the NJDEP: the Northeast, Raritan, Northwest, Lower Delaware, and Atlantic Coastal water regions (fig. 1). Each water region has been divided into three to five “watershed-management areas,” each of which encompasses a particular group of major rivers (fig. 2a-e). Each watershed management area consists of many smaller watersheds. Hydrologic data collected by Federal and State government agencies are invaluable as resources to policymakers who make decisions that affect the use of water in a particular watershed. The purpose of this report is to educate water-resource managers, policymakers, government officials, and the public about hydrologic concepts and the water-resource data needed to make informed decisions about water-management issues. (“Hydrologic” means relating to the occurrence, distribution, movement, and chemistry of all waters of the Earth (Fetter, 1980)). The first part of the report describes basic hydrologic concepts and includes explanations of the hydrologic cycle, the water budget, the surfacewater and ground-water flow systems, water-quality concepts and standards, and water use. The second part of the report summarizes the types of waterresource data that are available from Federal and State government agencies. Instructions on how to obtain the data and contact the appropriate Federal and State agencies, as well as suggestions for additional reading, also are included.

New Jersey↗

USGS2011

Changes in the chemistry of acidified Adirondack streams from the early 1980s to 2008

Lakes in the Adirondack region of New York have partially recovered in response to declining deposition, but information on stream recovery is limited. Here we report results of Adirondack stream monitoring from the early 1980s to 2008. Despite a 50% reduction in atmospheric deposition of sulfur, overall increases in pH of only 0.28 and ANC of 13 μeq L −1 were observed in 12 streams over 23 years, although greater changes did occur in streams with lower initial ANC, as expected. In the North Tributary of Buck Creek with high dissolved organic carbon (DOC) concentrations, SO 4 2 − "> SO42− concentrations decreased from 1999 to 2008 at a rate of 2.0 μmol L −1 y −1 , whereas in the neighboring South Tributary with low DOC concentrations, the decrease was only 0.73 μmol L −1 y −1 . Ca 2+ leaching decreased in the North Tributary due to the SO 4 2 − "> SO42− decrease, but this was partially offset by an increase in Ca 2+ leaching from increased DOC concentrations.

New York↗

USGS2026

A review of extraction techniques for per- and polyfluoroalkyl substances in graminaceous plants

Per- and polyfluoroalkyl substances (PFAS) are a wide-ranging class of manufactured chemicals that are environmentally persistent. Due to their ubiquity and resistance to degradation, PFAS readily bioaccumulate in a variety of environmental matrices and elicit a range of toxicological impacts. Despite an increase in research into these compounds, there is a clear gap in consensus on extraction techniques to quantify many PFAS in certain environmental media, particularly at critical points in agricultural food systems such as pasture grasses and feedstocks. Developing methods for more comprehensive and accurate extraction of PFAS in plant tissues is crucial for the biomonitoring of PFAS contamination in these ecosystems. This review seeks to identify relevant information pertaining to the partitioning of PFAS in plant matrices and evaluate the performance of previously established methods for the extraction of PFAS in graminaceous plants. Evaluated methods varied widely in extraction techniques, limits of detection and accuracy. This review provides a framework for enhancing PFAS analysis by tailoring extraction and cleanup strategies to both complex plant matrices and diverse analyte properties. Standardizing these methodologies will provide the high-quality data essential for ecotoxicologists and policymakers to accurately map the metabolic fate and ecological risks of these pollutants across food webs.

Critical Reviews in Analytical Chemistry↗