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At least 775 records · Page 43Linked to original sources

USGS2023

Application of surrogate technology to predict real-time metallic-contaminant concentrations and loads in the Clark Fork near Grant-Kohrs Ranch National Historic Site, Montana, water years 2019–20

Grant-Kohrs Ranch National Historic Site (GRKO) in southwestern Montana commemorates the frontier cattle era and its formative role in shaping the culture and history of the Western United States. The ranch was designated a national historic landmark in 1960 and a unit of the National Park Service (NPS) by Congress in 1972. The GRKO is unique because of its proximity to large-scale extraction, milling, and smelting of gold, silver, copper, and lead ore from the 1860s to the 1980s in the Butte mining district. During this time, mining and milling wastes were discarded in the upper Clark Fork Basin, resulting in the deposition of large amounts of waste materials (tailings) enriched with metallic contaminants (including cadmium, copper, iron, lead, manganese, zinc, and the metalloid trace element arsenic) in soils and in nearby streams and floodplains. Denuded vegetation and fish kills attributed to large concentrations of heavy metals caused the U.S. Environmental Protection Agency to designate a 120-mile section of the Clark Fork River (hereafter referred to as the “Clark Fork”), including GRKO, to be included on the National Priority List for Superfund cleanup in 1989. In 2018, with oversight from the Montana Department of Environmental Quality, the NPS began remediation of 2.6 miles of the Clark Fork as it flows through GRKO property. In 2019, the U.S. Geological Survey (USGS), in collaboration with the NPS, conducted a study using time-series data from backscatter signals from fixed-point turbidity and acoustic sensors with the intent to provide a high-resolution monitoring tool to estimate metallic-contaminant concentrations (MCCs) and loads during NPS remediation of the Clark Fork. Two monitoring sites at USGS streamgages on the Clark Fork on either side of GRKO property were instrumented with turbidity and acoustic sensors and surrogate relations were developed among time-series data and MCCs. The application of high-resolution surrogate data was used to infer contaminant source and fate and evaluate MCC values relative to aquatic-life standards. Using high-resolution surrogate data, it was determined that during spring runoff and storm-related runoff events, MCCs peaked at their highest values at streamflows markedly lower and prior to peak streamflow. Because MCCs peaked prior to streamflow peaks, it could be inferred that the source of MCCs originated from channel bed sediments in close spatial proximity to the monitoring site or from nearby streambanks and floodplains. High-resolution surrogate data revealed that copper concentrations in the Clark Fork exceeded chronic aquatic-life standards 90 percent of the time when streamflow exceeded 200 cubic feet per second (ft 3 /s) and exceeded acute aquatic-life standards 85 percent of the time when streamflow exceeded 260 ft 3 /s. These data helped support NPS management goals for evaluating variation in water quality during remediation of GRKO property, evaluating MCC values relative to aquatic-life standards, and quantifying benefits from Superfund remediation activities.

Montana↗

USGS2000

Organochlorine compounds in streambed sediment and in biological tissue from streams and their relations to land use, central Arizona

Streambed-sediment samples from 13 sites and biological-tissue samples from 11 sites in the Gila River Basin in central Arizona were analyzed for 32 organochlorine compounds in streambed sediment and 28 compounds in biological tissue during 1996 as part of the U.S. Geological Survey's National Water-Quality Assessment program. The objectives of the study were to determine the occurrence and distribution of organochlorine compounds and their relation to land use. Sampling sites were categorized on the basis of major land uses in the basin or the source of water in the stream. Because land uses were mixed or had changed over time, some land-use categories were combined. Sites were categorized as forest/rangeland (6), forest/urban (1), urban (4), or agricultural/urban (2). Thirteen organochlorine compounds were detected in streambed-sediment samples, and 10 were detected in tissue samples. The number of compounds found in streambed-sediment samples from individual sites ranged from 0 to 10, and the range for individual tissue samples was 0 to 7. Comparison of the number of detections in streambed-sediment samples to the number of detections in tissue samples from particular sites where both were sampled yielded five instances where more compounds were detected in streambed sediment, six instances where more compounds were detected in tissue, and five instances where the number of detections in streambed sediment and tissue were equal. The frequency of detection of particular compounds for sites where both streambed sediment and tissue were sampled resulted in five compounds being detected more frequently in streambed sediment, five more frequently in tissue, and three compounds that were equally frequent in streambed sediment and in tissue. Few contaminants were detected in samples from the forest/rangeland sites; greater numbers of compounds were detected at the urban sites and at the forest/urban site. The greatest number of compounds and the highest concentrations of many contaminants were detected at agriculture/urban sites. The compound detected most frequently in streambed-sediment and tissue samples was p,p'-DDE. Streambed-sediment guideline values for the protection of aquatic life for p,p'-DDE and total DDT were exceeded at both agricultural/urban sites, The streambed-sediment guideline value for the protection of aquatic life for total chlordane was exceeded at one agricultural/urban site, one urban site, and the forest/urban site. The streambed-sediment guideline value for the protection of aquatic life for total PCB’s was exceeded at one agricultural/urban site. Guideline values for the protection of fish-eating wildlife for total DDT and for toxaphene were exceeded only in samples from the two agricultural/urban sites. The guideline value for the protection of fish-eating wildlife for total PCB’s was equaled or exceeded in samples from two sites—one urban and one agricultural/urban site. Screening values established by the U.S. Environmental Protection Agency for the protection of human health for edible portions of fish were exceeded by total DDT and by toxaphene in fish-tissue samples from both agricultural/urban sites. The human-health criterion for total PCB’s was exceeded in two fish-tissue samples from an agricultural site and from an urban site. Tissue samples analyzed in this study were for whole fish, and thus, concentration data are not entirely comparable to the screening values of the U.S. Environmental Protection Agency. Because these exceedences were an order of magnitude above the criteria, however, it is possible that concentrations in the edible portions of fish from these locations could present a human- health risk. Analyses of samples of edible portions of fish from these locations would be needed to adequately assess the presence or absence of a human-health risk. The similarity of the results of this study to the results of other studies of organochlorine compounds in the environment suggests that there is a correlation between contaminants in sediment and biological-tissue samples and land uses. As with other studies of the occurrence and distribution of organochlorine contaminants in streambed sediments and biological tissue, this study shows that many organochlorine compounds continue to persist in the environment and thus could pose a threat to aquatic life, fish-eating wildlife, and possibly to humans who consume contaminated fish.

Arizona↗

USGS2002

Water quality, sediment quality, and stream-channel classification of Rock Creek, Washington, D.C., 1999-2000

Rock Creek Park is within the National Capital Region in Washington, D.C., and is maintained by the National Park Service. Part of Montgomery County, Maryland, and part of the District of Columbia drain into Rock Creek, which is a tributary of the Potomac River. Water quality in Rock Creek is important to biotic life in and near the creek, and in the Potomac River Basin and the Chesapeake Bay. The water quality of the Rock Creek Basin has been affected by continued urban and agricultural growth and development. The U.S. Geological Survey, in cooperation with the National Park Service, investigated water quality and sediment quality in Rock Creek over a 2-year period (1998?2000), and performed a stream-channel classification to determine the distribution of bottom sediment in Rock Creek. This report presents and evaluates water quality and bottom sediment in Rock Creek for water years 1999 (October 1, 1998 to September 30, 1999) and 2000 (October 1, 1999 to September 30, 2000). A synoptic surface-water assessment was conducted at five stations from June 23 to June 25, 1999, a temporal surface-water assessment was conducted at one station from February 18, 1999 to September 26, 2000, and bed-sediment samples were collected and assessed from three stations from August 17 to August 19, 1999. The synoptic surface-water assessment included pesticides (parent compounds and selected transformation products), field parameters, nutrients, and major ions. The temporal surface-water assessment included pesticides (parent compounds and selected transformation products) and field parameters. The bed-sediment assessment included trace elements and organic compounds (including low- and high-molecular weight polycyclic aromatic hydrocarbons, poly-chlorinated biphenyls, pesticides, and phthalates). Some, but not all, of the pesticides known to be used in the area were included in the synoptic water-quality assessment, the temporal water-quality assessment, and the bed-sediment assessment. In addition to the water-quality and sediment-quality assessments, a Rosgen stream-channel classification was performed on a 900-foot-long segment of Rock Creek. In the synoptic water-quality assessment, two pesticides were found to be above published criteria for the protection of aquatic life. In the temporal water-quality assessment, four pesticides were found to be above published criteria for the protection of aquatic life. In the bed-sediment assessment, 8 trace elements, 14 polycyclic aromatic hydrocarbons, 6 pesticides, and 1 phthalate compound were found to be above published criteria for the protection of aquatic life. In the Rosgen classification, a comparison to a previous classification for this segment showed an increase in sands and other fine-grained sediments in the creek bed.

Rock Creek, Washington D.C.↗

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↗

USGS2003

Occurrence and Distribution of Pesticides in the St. Lucie River Watershed, South-Central Florida, 2000-01, Based on Enzyme-Linked Immunosorbent Assay (ELISA) Screening

The St. Lucie River watershed is a valuable estuarine ecosystem and resource in south-central Florida. The watershed has undergone extensive changes over the last century because of anthropogenic activities. These activities have resulted in a complex urban and agricultural drainage network that facilitates the transport of contaminants, including pesticides, to the primary canals and then to the estuary. Historical data indicate that aquatic life criteria for selected pesticides have been exceeded. To address this concern, a reconnaissance was conducted to assess the occurrence and distribution of selected pesticides within the St. Lucie River watershed. Numerous water samples were collected from 37 sites among various land-use categories (urban/built-up, citrus, cropland/pastureland, and inte-grated). Samples were collected at inflow points to primary canals (C-23, C-24, and C-44) and at control structures along these canals from October 2000 to September 2001. Samples were screened for four pesticide classes (triazines, chloroacetanilides, chlorophenoxy compounds, and organophosphates) by using Enzyme-Linked Immunosorbent Assay (ELISA) screening. A temporal distribution of pesticides within the watershed was made based on samples collected at the integrated sites during different rainfall events between October 2000 and September 2001. Triazines were detected in 32 percent of the samples collected at the integrated sites. Chloroacetanilides were detected in 60 percent of the samples collected at the integrated sites, with most detections occurring at one site. Chlorophenoxy compounds were detected in 17 percent of the samples collected at the integrated sites. Organophosphates were detected in only one sample. A spatial distribution and range of concentration of pesticides at the 37 sampling sites in the watershed were determined among land-use categories. Triazine concentrations ranged from highest to lowest in the citrus, urban/built-up, and integrated areas, respectively. The highest median triazine concentration was found in the cropland/pastureland area. Chloroacetanilide concentra-tions ranged from highest to lowest in the citrus, integrated, urban/built-up, and cropland/pastureland areas, respectively. Chlorophenoxy compound concentrations ranged from highest to lowest in the urban/built-up, integrated, citrus, and cropland/pastureland areas, respectively. The maximum concentrations of triazines, chloroacetanilides, and chlorophenoxy compounds were 0.63, 1.0, and 14 micrograms per liter, respectively. Organophosphate was detected once at an integrated site at a concentration of 0.20 microgram per liter. Currently, the U.S. Environmental Protection Agency has no aquatic life guidelines for atrazine and metolachlor. However, assuming that all triazine and metolachlor concentrations from ELISA and gas chromatography/mass spectrometry (GC/MS) analyses were the result of atrazine and metolachlor detections, no concentrations exceeded the Canadian aquatic life guidelines for atrazine and metolachlor. One organophosphate detection (0.2 microgram per liter) did exceed the U.S. Environmental Protection Agency aquatic life guideline for chlorpyrifos. The deethylatrazine/atrazine ratio (DAR) is an important indicator of atrazine transport in the environment. The DAR ranged from 0.25 to 0.33, indicating that postapplication runoff was the most likely source of atrazine to the environment at the time of sampling. Deisopropylatrazine is a metabolite of atrazine and structurally similar compounds, such as simazine and cyanazine. The deisopropylatrazine/deethylatrazine ratio (D2R) is an indicator of nonpoint sources of deisopropylatrazine to the environment. The ratio ranged from 1 to 3 in this study, indicating simazine was an important source of deisopropylatrazine to the environment at the time of sampling, as opposed to atrazine alone. Confirmation analyses by GC/MS for triazines detected by ELISA indicated the presence of atrazine, simazine, deethylatrazine, and deisopropylatrazine. Metolachlor, however, or any of the pesticides for which the ELISA test is cross reactive (acetochlor, butachlor, propachlor, or alachlor) were not detected by GC/MS analysis. The chloroacetanilide detections may be the result of antibody cross reactivity with two metolachlor metabolites; namely, metolachlor ethane sulfonic acid (ESA) and metolachlor oxanilic acid (OA). Metalaxyl, a fungicide also used in the watershed, cross reacts with metolachlor antibodies at low concentrations. Quality assurance efforts included the collection of duplicate samples and equipment blanks for every 10 and 20 environmental samples collected, respectively. All equipment blank test results showed concentrations below the method detection limit (MDL) for triazines, chlorophenoxy compounds, and organophosphates. Chloroacetanilide concentrations ranged from the method detection limit of 0.05 to 0.07 microgram per liter. Further results indicated statistically significant differences between triazines by ELISA and atrazine by GC/MS when ELISA results are converted to the MDL. There was, however, no statistically significant difference between triazines determined by ELISA and atrazine determined by GC/MS when ELISA results were converted to one-half the MDL.

Florida↗

USGS1988

Reconnaissance investigation of water-quality, bottom sediment, and biota associated with irrigation drainage in the Lower Rio Grande Valley and Laguna Atascosa National Wildlife Refuge, Texas, 1986-87

In 1986, the Department of the Interior conducted reconnaissance investigations in nine areas of the western conterminous United States to determine whether irrigation drainage has caused or has the potential to cause harmful effects to human health, fish, and wildlife, or may adversely affect the suitability of water for beneficial uses. Data collected in the lower Rio Grande valley and Laguna Atascosa National Wildlife Refuge reconnaissance investigation indicate that concentrations of dissolved minor elements in water are small. The maximum dissolved concentrations of arsenic, cadmium, mercury, chromium, selenium, and zinc exceed the 75th-percentile baseline values developed for the study; however, maximum dissolved concentrations of cadmium, mercury, and selenium exceeded the 75th-percentile baseline values by 1 microgram per liter or less. Concentrations of dissolved boron increased significantly from west to east. The smallest concentration of dissolved boron, 220 micrograms per liter, was detected in International Falcon Reservoir. The largest concentration of dissolved boron, 11,000 micrograms per liter, was detected on the refuge in Athel Pond. No chlorophenoxy herbicides were detected in water during the June 1986 sampling. Simazine, prometone, and atrazine were the only triazine herbicides detected, and concentrations of these herbicides did not exceed 0.8 microgram per liter. DDE, the only organochlorine Insecticide detected in water, was detected at two locations at concentrations of 0.01 micrograms per liter. Methyl parathion, malathion, and diazinon were the only organophosphorus compounds detected in the June 1986 sampling, and the maximum concentrations of these compounds were 0.75, 0.71, and 0.26 micrograms per liter, respectively. The analysis of three samples collected in August 1986 indicate that the types of pesticides collected during runoff were similiar to those detected during the June 1986 sampling. The exception was that the herbicide 2,4-D was detected during runoff. Concentrations of dissolved cadmium exceeded the chronic criteria for freshwater aquatic life in the Cayo Atascoso in the Laguna Atascosa National Wildlife Refuge. Chromium exceeded the acute and chronic freshwater criteria at four locations in the refuge and in the Laguna Madre. Chromium also exceeded the chronic saltwater criteria in Athel Pond. Concentrations of dissolved copper exceeded the acute and chronic criteria for saltwater aquatic life at 13 locations. Mercury exceeded the chronic criteria for freshwater and saltwater aquatic life at three locations, and dissolved nickel concentrations exceeded the chronic criteria for saltwater aquatic life in the Rio Grande at Anzalduas Dam and in the Resaca de los Frenos near Russeltown. No organophosphorus insecticides, polychlorinated napthalenes, or polychlorinated biphenyl compounds were detected in four bed-sediment samples. DDE, an organochlorine insecticide, was detected in all four samples at concentrations ranging from 0.2 to 34 micrograms per kilogram. Chlordane, ODD, DDE, DOT, and dieldrin were all detected in the Resaca de los Fresnos at U.S. Highway 77 at San Benito with concentrations of 4.0, 9.7, 9.3, 7.3, and 0.1 micrograms per kilogram, respectively. Data collected by U.S. Fish and Wildlife Service in 1985 indicate that DDE was detected in approximately 75 percent of the bed sediment samples analyzed. The maximum concentration detected in that study was 6.0 micrograms per gram; the median concentration was 0.01 micrograms per gram. Minor-element data from 22 fish samples indicate that the maximum concentrations of arsenic, copper, mercury, selenium, and zinc exceeded the 85thpercentile baseline concentrations established by the U.S. Fish and Wildlife Service for the National Contaminant Biomonitoring Program. None of the median concentrations of these minor elements exceeded the baseline concentrations. The maximum concentrations of aluminum, barium, iron, manganese, and tin were detected in fish collected from International Falcon Reservoir. This reservoir stratifies in the summer, and minor elements may be released from the bed sediments in the deep parts of the reservoir and incorporated into the food chain. Toxaphene was detected in 11 fish samples; detectable concentrations ranged from 0.98 to 5.1 micrograms per gram, wet weight. DOT also was detected in 11 fish samples with concentrations ranging from 0.021 to 0.066 micrograms per gram, wet weight. ODD was detected in 21 fish samples; concentrations ranged from 0.015 to 0.16 micrograms per gram, wet weight. DDE was detected in all 22 fish samples, and concentrations ranged from 0.36 to 9.9 micrograms per gram, wet weight. The maximum concentrations of DOT and ODD exceeded the 1980-81 baseline concentrations. The median and maximum concentrations of toxaphene and DDE exceeded the 1980-81 baseline concentrations. The largest concentrations of toxaphene, ODD, and DDE in fish were all measured in samples collected at the Main Floodway near Progreso.

Texas↗

USGS1995

Water-quality assessment of the upper Snake River Basin, Idaho and western Wyoming — Summary of aquatic biological data for surface water through 1992

The 35,800-square-mile upper Snake River Basin in eastern Idaho and western Wyoming was one of 20 areas selected for water-quality study under the National Water-Quality Assessment Program. As part of the initial phase of the study, data were compiled to describe the current (1992) and historical aquatic biological conditions of surface water in the basin. This description of natural and human environmental factors that affect aquatic life provides the framework for evaluating the status and trends of aquatic biological conditions in streams of the basins. Water resource development and stream alterations, irrigated agriculture, grazing, aquaculture, and species introductions have affected stream biota in the upper Snake River Basin. Cumulative effects of these activities have greatly altered cold-water habitat and aquatic life in the middle Snake River reach (Milner Dam to King Hill). Most of the aquatic Species of Special Concern in the basin , consisting of eight native mollusks and three native fish species, are in this reach of the Snake River. Selected long-term studies, including comprehensive monitoring on Rock Creek, have shown reduced pollutant loadings as a result of implementing practice on cropland; however, aquatic life remains affected by agricultural land use. Community level biological data are lacking for most of the streams in the basin, especially for large river. Aquatic life used to assess water quality of the basin includes primarily macroinvertebrate and fish communities. At least 26 different macroinvertebrate and fish community metrics have been utilized to assess water quality of the basin. Eight species of macroinvertebrates and fish are recognized as Species of Special Concern. The native fish faunas of the basin are composed primarily of cold-water species representing 5 families and 26 species. An additional 13 fish species have been introduced to the basin. Concentrations of synthetic organic compounds and trace-element contaminants in whole fish collected in the basin during 1970-90 generally did not exceed National Academy of Sciences and National Academy of Engineering concentration guidelines or the 1980-81 geometric mean concentrations from samples collected as part of the U.S. Fish and Wildlife Service National Contaminant Biomonitoring Program. Currently, there are no State fish consumption advisories on any streams in the basin, The organochlorine compounds DDT and PCB's were the most frequently detected fish tissue contaminant. Selected long-term data on DDT, its metabolites, and PCB's indicate decreasing concentrations of these compounds. Arsenic, mercury, and selenium were slightly elevated compared with nationwide baseline concentrations and may indicate bioaccumularion in the food chain. Concentrations of most other trace elements in fish tissue were below levels of concerns for the protection of humans and wildlife.

Idaho, Wyoming↗

USGS1999

Evaluation of processes affecting 1,2-dibromo-3-chloropropane (DBCP) concentrations in ground water in the eastern San Joaquin Valley, California: Analysis of chemical data and ground-water flow and transport simulations

Future use of the sole-source aquifer near Fresno in the eastern San Joaquin Valley, California, will depend, in part, on how long 1,2-dibromo-3-chloropropane (DBCP), an agricultural fumigant banned from use since the late 1970's, persists at concentrations greater than the maximum contaminant level of 0.2 micrograms per liter (mg/L). Field data indicate that DBCP concentrations in ground water have decreased since the late 1970's. Laboratory experiments by earlier investigators show that DBCP transformed to 2-bromoallyl alcohol (BAA) under conditions similar to in situ conditions, with an estimated half-life ranging from 6.1 (pH 7.8, 21.1 degrees Celsius) to 141 years (pH 7.0, 15 degrees Celsius). For this current study, a detailed hydrogeologic investigation was done to assess the relative importance of chemical transformation, dispersion, and ground-water pumping and reapplication of irrigation water in affecting DBCP concentrations. Ground-water samples were collected from 20 monitoring wells installed along a 4.6-kilometer transect. DBCP concentrations in these samples ranged from less than the detection limit of 0.03 mg/L to a maximum of 6.4 mg/L. Results of chlorofluorocarbon (CFC) age dating indicate that DBCP occurs in water that ranges in age from about 2 to 41 years. The primary transformation product BAA, which was identified during previous laboratory studies, was not detected at or greater than 0.03 mg/L in any of the 20 ground-water samples. The lack of detection of BAA indicates that transformation to BAA is insignificant relative to other processes controlling DBCP concentrations. Results from this current study indicate that the in situ hydrolysis half-life for DBCP to BAA is much greater than the laboratory-determined values. Estimated initial concentrations of DBCP, calculated using CFC-estimated travel times and a half-life of 6.1 years, indicate that maximum initial concentrations are consistent with maximum measured concentrations in ground water. In contrast to initial DBCP concentrations, the estimated initial nitrate concentrations indicate that nitrate concentrations in recharge water have increased with time. A conceptual two-dimensional numerical flow and transport modeling approach was used to test hypotheses addressing dispersion, transformation rate, and in a relative sense, the effects of ground- water pumping and reapplication of irrigation water on DBCP concentrations in the aquifer. The flow and transport simulations, which represent hypothetical steady-state flow conditions in the aquifer, were used to refine the conceptual understanding of the aquifer system rather than to predict future concentrations of DBCP. Results indicate that dispersion reduces peak concentrations, but this process alone does not account for the apparent decrease in DBCP concentrations in ground water in the eastern San Joaquin Valley. Ground-water pumping and reapplication of irrigation water may affect DBCP concentrations to the extent that this process can be simulated indirectly using first-order decay. Transport simulation results indicate that the in situ 'effective' half-life of DBCP caused by processes other than dispersion and transformation to BAA could be on the order of 6 years.

California↗

USGS1991

National water summary 1988–89 — Hydrologic events and floods and droughts

National Water Summary 1988-89 - Hydrologic Events and Floods and Droughts documents the occurrence in the United States, Puerto Rico, and the U.S. Virgin Islands of two types of extreme hydrologic events floods and droughts on the basis of analysis of stream-discharge data. This report details, for the first time, the areal extent of the most notable floods and droughts in each State, portrays their severity in terms of annual peak discharge for floods and annual departure from long-term discharge for droughts for selected stream-gaging stations, and estimates how frequently floods and droughts of such severity can be expected to recur. These two types of extreme hydrologic events are very different in their duration, cause, areal extent, and effect on human activities. Floods are short-term phenomena that typically last only a few hours to a few days and are associated with weather systems that produce unusually large amounts of rain or that cause snow to melt quickly. The large amount of runoff produced causes rivers to overflow their banks and, thus, is highly dangerous to human life and property. In contrast, droughts are long-term phenomena that typically persist for months to a decade or more and are associated with the absence of precipitation producing weather. They affect large geographic areas that can be statewide, regional, or even nationwide in extent. Droughts can cause great economic hardship and even loss of life in developing countries, although the loss of life results almost wholly from diminished water supplies and catastrophic crop failures rather than from the direct and obvious peril to human life that is common to floods. The following discussion is an overview of the three parts of this 1988-89 National Water Summary "Hydrologic Conditions and Water-Related Events, Water Years 1988-89," "Hydrologic Perspectives on Water Issues," and "State Summaries of Floods and Droughts." Background information on sources of atmospheric moisture to the States from a study sponsored by the U.S. Geological Survey to enable related information to be presented in each of the State summaries also is given.

Water Supply Paper↗

USGS2017

No substitute for survival: Perturbation analyses using a Golden Eagle population model reveal limits to managing for take

Conserving populations of long-lived birds of prey, characterized by a slow life-history (e.g., high survival and low reproductive output), requires a thorough understanding of how variation in their vital rates differentially affects population growth. Stochastic population modeling provides a framework for exploring variation in complex life histories to better understand how environmental and demographic variation within individual vital rates affects population dynamics. Specifically, we used life-stage simulation analysis (LSA) to identify those life-history characteristics that most affect population growth and are amenable to management actions. The Golden Eagle ( Aquila chrysaetos ) is a wide-ranging raptor of conservation concern, which has been adopted as a focal species for conservation planning. Golden Eagle population trends in western North America currently appear stable. Yet an expanding human footprint that may increase mortality stimulated our investigation into the ability of populations to sustain reduced survival. We fit mixed-effects models to published estimates of vital rates to estimate the mean and process variation of productivity (young fledged per pair) and survival for use in a LSA framework. As expected, breeding adult survival had the greatest relative effect on population growth, though productivity explained the most variation in growth. Based on perturbation analyses, we demonstrate that even minor reductions in breeding adult survival (<4.5%) caused otherwise stable populations to decline. Despite its importance, precise estimates of spatial and temporal variation in breeding adult survival are poorly documented. Importantly, we found that the ability for increases in reproductive output to compensate for decreased survival was very limited. To maintain stable populations, declines in survival >4% required increases in productivity that generally exceed the evolutionary potential for Golden Eagles. Our findings support the current U.S. Fish and Wildlife conservation strategy which mitigates eagle “take” via efforts to reduce mortality elsewhere.

Journal of Raptor Research↗

USGS2026

Age and colony variation in Adélie penguin metapopulation vital rates: Insights from a 25-year mark–recapture study

Understanding how vital rates vary with age, life-history stage, and among populations is fundamental for predicting the demographic consequences of environmental change, especially in longer-lived species with complex life histories. These species often exhibit delayed maturity and iteroparity, making nuanced demographic insights critical for assessing their long-term viability. This study investigated age- and colony-related variation in Adélie penguin vital rates including survival, recruitment, and breeding propensity. We used mark–recapture data collected over 25 years (1996–2020) from three Adélie penguin breeding colonies that differed in population sizes and trends but comprised a metapopulation located at capes Royds, Bird, and Crozier on Ross Island, Antarctica. We used multi-state models to estimate survival and detection rates relative to reproductive state and breeding colony and estimated transition probabilities reflecting movements between reproductive states and colonies. Apparent survival varied by reproductive state, colony, and age and averaged 0.80 (SD = 0.02) at Bird, and 0.72 (SD = 0.03) and 0.73 (SD = 0.03) at Crozier and Royds, respectively, for pre-breeders age 2–7 years with strong declines in pre-breeder survival after age 8. We observed less age-related variation in survival of breeders and non-breeders, but we observed differences between colonies with lower survival for breeders (0.72 to 0.80) compared to non-breeders (0.75 to 0.82). The average probability of surviving the first 2 years after fledging ranged from 0.43 (SD = 0.14) at Royds and Crozier (0.43, SD = 0.10) to 0.55 (SD = 0.15) at Bird. Movement between colonies was highest for pre-breeders (0.00%–12.00% depending on age and colony) and lowest for breeders (<0.20%). We observed the lowest age-related recruitment rates at Royds, with recruitment at Crozier almost twice as high, and intermediate at Bird. Breeding propensity was highest at Crozier and lowest at Bird. Colony-specific variation in vital rates likely contributed differently to population trajectories, suggesting that care must be taken to extrapolate vital rate estimates across colonies even within a metapopulation. These findings also highlight the importance of considering age, life-history stage, and geographic variation when assessing population vital rates in species with complex life histories.

Frontiers in Ecology and Environment↗

USGS2026

A genomic tool to tackle cryptic diversity demonstrates the potential for off-target use of GT-seq panels

A comprehensive understanding of life history is vital to successful species conservation and management. When different life history stages are accompanied by considerable morphological or cryptic variation, such as the egg and larval phases exhibited by most fishes, genomic tools are essential for identifying species so that early-life ecology questions can be studied. Genotyping-in-thousands by sequencing (GT-seq) has recently emerged as a targeted and efficient approach for species identification. We leveraged existing genomic and transcriptomic data to develop a GT-seq panel capable of differentiating the members of the Coregonus artedi complex, a radiation of salmonids in the Laurentian Great Lakes whose members are indistinguishable with mitochondrial DNA barcoding loci and are the focus of bi-national conservation initiatives. Our panel of 494 loci was able to assign fishes in the C. artedi complex to species and lake. We examined cross-amplification in other coregonines with overlapping distributions and found that congeneric Lake Whitefish ( C. clupeaformis ) cross-amplified at 94% of loci and confamilial Round and Pygmy Whitefish ( Prosopium spp.) cross-amplified at 42% and 38% of loci, respectively. We adapted bioinformatic probes to account for Prosopium -specific variants including 22 new SNPs and developed a whitelist of 428 SNPs capable of distinguishing these whitefishes. Finally, we demonstrated performance by identifying 3,066 coregonine larvae and juveniles collected in spring 2019-2021 from Lake Superior. These results hold promise for future insights into the species-specific ecology of early life coregonines and demonstrate the flexibility of GT-seq panels, which may cross-amplify hundreds of informative genome-wide loci in related taxa.

BioRxiv↗

USGS2008

Estimating total population size for adult female sea turtles: Accounting for non-nesters

Assessment of population size and changes therein is important to sea turtle management and population or life history research. Investigators might be interested in testing hypotheses about the effect of current population size or density (number of animals per unit resource) on future population processes. Decision makers might want to determine a level of allowable take of individual turtles of specified life stage. Nevertheless, monitoring most stages of sea turtle life histories is difficult, because obtaining access to individuals is difficult. Although in-water assessments are becoming more common, nesting females and their hatchlings remain the most accessible life stages. In some cases adult females of a given nesting population are sufficiently philopatric that the population itself can be well defined. If a well designed tagging study is conducted on this population, survival, breeding probability, and the size of the nesting population in a given year can be estimated. However, with published statistical methodology the size of the entire breeding population (including those females skipping nesting in that year) cannot be estimated without assuming that each adult female in this population has the same probability of nesting in a given year (even those that had just nested in the previous year). We present a method for estimating the total size of a breeding population (including nesters those skipping nesting) from a tagging study limited to the nesting population, allowing for the probability of nesting in a given year to depend on an individual's nesting status in the previous year (i.e., a Markov process). From this we further develop estimators for rate of growth from year to year in both nesting population and total breeding population, and the proportion of the breeding population that is breeding in a given year. We also discuss assumptions and apply these methods to a breeding population of hawksbill sea turtles (Eretmochelys imbricata) from the Caribbean. We anticipate that this method could also be useful for in-water studies of well defined populations.

Book chapter↗

USGS2000

Impacts of toxic thresholds of sediment-associated contaminants to robust redhorse (Moxostoma robustum) in the Lower Oconee River

The robust redhorse is a ?Species-at-Risk? in the lower Oconee River, GA. The population is composed of aging adults with little natural recruitment. Factors contributing to the loss of early-life stages are unknown, but contaminants associated with fine sediments may play a role. The objectives of this study were to determine toxicities of sediments and pore waters from the Oconee River to early-life stages of robust redhorse and to establish toxic thresholds of metals (Cd, Cu, Mn, Zn) and ammonia, elements potentially threatening this species. Depositional sediments were collected from the only known spawning site and three sites downstream of major tributaries. Sediment pore waters were extracted in the laboratory from all sites and in situ at two sites. Toxicity tests with sediments, pore waters and metal solutions were initiated with eggs, yolk-sac fry and swim-up fry to determine effects on the life stage initially exposed as well as effects manifested in later developmental stages. Survival and growth were test endpoints, and toxicity was observed in both sediments and pore waters. Although the yolk- sac stage was the most sensitive across all tests, sediment toxicity was elicited only in tests initiated with eggs that developed through the yolk-sac stage. Toxicity appeared to be due to Mn in sediment and pore water exposures, but was more prevalent in pore waters. Sediment handling and the associated effects on redox potential contributed to the elevated concentrations of Mn in pore waters. Pore waters extracted in situ had significantly less Mn and were less toxic than laboratory-extracted pore waters. These data suggest that sediment-associated Mn may impact early-life stages of robust redhorse in the Oconee River.

Society of Environmental Toxicology and Chemistry,↗

USGS1985

Limnocythere bradburyi n.sp.: a modern ostracode from central Mexico and a possible Quaternary paleoclimatic indicator

Limnocythere bradburyi is a new species of nonmarine ostracode that is living in several lakes in the central Mexican Plateau. These lakes are shallow, turbid, and pan-shaped, having relatively unstable and fluid substrates. Water levels of these lakes are high in the summer and low or dry in the winter. These lakes usually contain fresh to slightly saline water during the rainy season (summer-fall) and slightly saline water during the dry season (winter-spring), and have solute composition that is dominated by Na+, HCO3--CO32-, Cl- ions. The regional climate is characterized as humid temperate with mild equitable temperatures throughout the year. Winter temperatures are usually above 0oC, whereas summer temperatures are commonly below 30oC. The water temperature of the lakes containing L. bradburyi generally reflects atmospheric temperatures. The ostracode's life cycle coincides with the climatic wet cycle and is therefore completed during the warmest period of the year, which is in marked contrast to ostracodes living in lakes in the US and Canada that usually begin their life cycle with the spring rain and snow melt in cold water and complete their life cycle in warm water. This contrasting climatic life-cycle pattern between central Mexico and the US may be sufficient to explain why L. bradburyi occurs commonly in many Quaternary deposits in the southwestern US, but has not been found living in the US.

Journal of Paleontology↗

USGS2011

Growth characteristics and otolith analysis on age-0 American shad

Otolith microstructure analysis provides useful information on the growth history of fish (Campana and Jones 1992, Bang and Gronkjaer 2005). Microstructure analysis can be used to construct the size-at-age growth trajectory of fish, determine daily growth rates, and estimate hatch date and other ecologically important life history events (Campana and Jones 1992, Tonkin et al. 2008). This kind of information can be incorporated into bioenergetics modeling, providing necessary data for estimating prey consumption, and guiding the development of empirically-based modeling scenarios for hypothesis testing. For example, age-0 American shad co-occur with emigrating juvenile fall Chinook salmon originating from Hanford Reach and the Snake River in the lower Columbia River reservoirs during the summer and early fall. The diet of age-0 American shad appears to overlap with that of juvenile fall Chinook salmon (Chapter 1, this reoprt), but juvenile fall Chinook salmon are also known to feed on age-0 American shad in the reservoirs (USGS unpublished data). Abundant, energy-dense age-0 American shad may provide juvenile fall Chinook salmon opportunities for rapid growth during the time period when large number of age-0 American shad are available. Otolith analysis of hatch dates and the growth curve of age-0 American shad could be used to identify when eggs, larvae, and juveniles of specific size classes are temporally available as food for fall Chinook salmon in the lower Columbia River reservoirs. This kind of temporally and spatially explicit life history information is important to include in bioenergetics modeling scenarios. Quantitive estimates of prey consumption could be used with spatially-explicit estimates of prey abundance to construct a quantitative assessment of the age-0 American shad impact on a reservoir food web. Analysis of the age-0 American shad growth trajectory or individual growth records may show evidence of differential growth rates over time that may be linked to environmental conditions such as water temperature (Leach and Houde 1999, Meekan et al. 2003), size-selective mortality (Folkvord et al. 1997), developmental changes in metabolic rate (Bang and Gronkjaer 2005, Bochdanksy et al. 2005), feeding ability (Schmitt and Holbrook 1984, Luecke 1986, Johnson and Dropkin 1995, Johnson and Dropkin 1996), and intra- and inter-specific competition (Crecco and Savoy 1987, Marchand and Boisclair 1998, Gadomski and Wagner 2009). For example, environmental conditions associated with John Day reservoir may eliminate or reduce the availability of many aquatic and terrestrial insect prey types (Rondorf et al. 1990). Many juvenile fishes, including age-0 American shad and juvenile fall Chinook salmon may be foraging on limited insect prey in John Day Reservoir (Gadomski and Wagner 2009). Because larger insect prey has higher energy densities than most zooplankton prey, and insect availability may be limited in John Day reservoir, the growth of American shad may be constrained once fish grow to a size where they could exploit larger, more energy-dense insect prey (Mayer and Wahl 1997). Similarly, as age-0 American shad grow, they are able to forage on larger zooplankton with higher energy densities than smaller individuals of the same species, or other smaller-bodied zooplankton species (Schael et al. 1991, Mayer and Wahl 1997). Intra- and inter-specific demand for larger-bodied and higher energy zooplankton prey may reduce the availability of these prey items (Tabor et al. 1996). Constrained growth increments on the otolith microstructure of juvenile American shad or other planktivorous fish could help identify important interactions between fishes that may be linked to the year class strength of age-0 American shad and prey partitioning in John Day reservoir. The objective of this study was to determine time of hatch and size-at-age of age-0 American shad in lower Columbia River reservoirs for use with the American shad and fall Chinook salmon bioenergetic models. Size-at-age data on age-0 American shad can be used to generate quantitative estimates of prey consumption with the American shad bioenergetics model. Otolith microstructure analysis was used to provide reference points on the temporal availability of early life stages and sizes of American shad in the reservoir (Limburg 1996a,b, Limburg et al. 1999). Additional analyses on the age-0 American shad growth trajectory in John Day reservoir may reveal differential growth patterns during the early life history of these fish that are linked to developmental differences between individual fish, transient environmental conditions, or food web constraints (Limburg 1996a).

Idaho, Montana, Oregon, Washington, Wyoming↗

USGS2005

Forestry practices and aquatic biodiversity: Fish

In the Pacific Northwest, fish communities are found in a diverse array of aquatic habitats ranging from the large coastal rivers of the temperate rainforests, to the fragmented and sometimes ephemeral streams of the xeric interior basins, and high-elevation streams and lakes in the mountainous areas (Rieman et al. 2003). Only high-elevation lakes and streams isolated above barriers to fish passage remained historically devoid of fish because they were never invaded following Pleistocene glaciation (Smith 1981). Despite this widespread distribution and once great population abundances, taxonomic diversity of fishes in these forested systems is naturally lower than in aquatic habitats in the eastern U.S. (Reeves, Bisson, and Dambacher 1998). Interactions among factors that influence species richness in aquatic systems (e.g., basin size, long-term stability of habitat, and barriers to colonization; Smith 1981) continue to influence the occurrence and persistence of fishes in these systems today. Consequently, the larger low-elevation rivers and estuaries support the greatest variety of fish species. In the high-elevation tributary streams, fish communities are less complex because these aquatic systems were less climatically and geologically stable, and fish populations were smaller and more prone to local extirpation. Furthermore, barriers to fish passage inhibited dispersal and colonization (Smith 1981). Streams in forested landscapes generally support salmon and trout, Oncorhynchus spp., whitefish Prosopium spp., sculpins Cottus spp., suckers Catostomus spp., and minnows (Cyprinidae), but in some of the colder streams, chars (e.g., Salvelinus confluentus and Salvelinus malma ) and lampreys (Petromyzontidae)may also occur (Rieman et al. 2003). Although biodiversity defined in terms of fish species richness is low in the Pacific Northwest, intraspecific variability is high, and polytypic fish species are common in the diverse aquatic habitats of the region. For example, the salmonids in the coastal rivers and streams, and the larger interconnected streams, rivers, and lakes of the interior exhibit a variety of ecotypes and migratory life histories (Healey 1986; Trotter 1989; Larson and McIntire 1993; Northcote 1997). This life-history variation appears to be associated with adaptation to spatial and temporal variation in environment (e.g., Schaffer and Elson 1975; Carl and Healey 1984; Beacham and Murray 1987), and there is some evidence of the genetic heritability of life-history traits (Carl and Healey 1984; Gharrett and Smoker 1993; Hankin, Nicholas, and Downey 1993). Persistence of any level of biological organization (e.g., life-history type, population, metapopulation, subspecies, species, community) is related to the interaction of environmental and biological components, and intraspecific diversity is a means of spreading risk ( sensu den Boer 1968) of extirpation in dynamic environments (Gresswell 1999). Unfortunately, despite the broad distribution and extensive intraspecific diversity, persistence of native fishes is uncertain in the Pacific Northwest. Many populations of anadromous salmonids, once synonymous with vigorous biological communities throughout the region, are threatened with extinction (Nehlsen, Williams, and Lichatowich 1991; Frissell 1993; Thurow, Lee, and Rieman 1997). Furthermore, over half of the native taxa in the Columbia River Basin are either listed under the Endangered Species Act, are being considered for listing, or are deemed sensitive by the management agencies (Lee et al. 1997; Thurow, Lee, and Rieman 1997). Potamodromous species like bull trout Salvelinus confluentus are estimated to occur as strong populations in less than 5% of their potential range (Rieman, Lee, and Thurow 1997). Although not currently listed under the endangered species list, the coastal cutthroat trout Oncorhynchus clarki is managed as a sensitive species in Oregon and California (Hall, Bisson, and Gresswell 1997). Native non-game fishes have rarely been monitored, but populations of species such as large-scale suckers ( Catostomus macrocheilus ), squawfish ( Ptychocheilus umpquae ), and Pacific lamprey ( Lampetra tridentata ) also are declining in some drainages (Oregon Department of Fish and Wildlife, unpublished data).

Pacific Northwest↗

USGS2007

Viability criteria for steelhead of the south-central and southern California coast

Recovery planning for threatened and endangered steelhead requires measurable, objective criteria for determining an acceptably low risk of extinction. Here we propose viability criteria for two levels of biological organization: individual populations, and groups of populations within the SouthCentral/Southern California Coast Steelhead Recovery Planning Domain. For populations, we adapt criteria commonly used by the IUCN (The World Conservation Union) for identifying at-risk species. For groups of populations we implement a diversity-based “representation and redundancy rule,” in which diversity includes both life-history diversity and biogeographic groupings of populations. The resulting criteria have the potential for straightforward assessment of the risks posed by evolutionary, demographic, environmental, and catastrophic factors; and are designed to use data that are readily collected. However, our prescriptive approach led to one criterion whose threshold could not yet be specified due to inadequate data, and others in which the simplicity of the criteria may render them inefficient for populations with stable run sizes or stable life-history polymorphisms. Both of these problems could likely be solved by directed programs of research and monitoring aimed at developing more efficient (but equally risk-averse) “performance-based criteria.” Of particular utility would be data on the natural fluctuations of populations, research into the stabilizing influence of life-history polymorphisms, and research on the implications of drought, wildfires, and fluvial sediment regimes. Research on estuarine habitat could also yield useful information on the generality and reliability of its role as nursery habitat. Currently, risk assessment at the population level is not possible due to data deficiency, highlighting the need to implement a comprehensive effort to monitor run sizes, anadromous fractions, spawner densities and perhaps marine survival. Assessment at the group level indicates a priority for securing inland populations in the southern Coast Ranges and Transverse Ranges, and a need to maintain not just the fluvial-anadromous life-history form, but also lagoon-anadromous and freshwater-resident forms in each population.

Report↗