Juvenile salmonids migrate hundreds of kilometers from their natal streams to mature in the ocean. Throughout this migration, they respond to environmental cues such as local water velocities and other stimuli to direct and modulate their movements, often through heavily modified riverine and estuarine habitats. Management strategies in an uncertain future of climate change and altered land use regimes depend heavily on being able to reliably predict their ocean entry timings, route use, and survival rates through rivers and estuaries. We developed a spatially-explicit agent-based model of fish movement in response to hydrodynamic flows that uses movement dynamics gleaned from multi-dimensional tracking datasets of acoustically tagged juveniles moving through an urbanized, branched tidal estuary. We demonstrate how such models can be calibrated, and we apply it to the Sacramento-San Joaquin Delta in Central California. The quality of the out-of-sample validation of the model to predict juvenile salmon survival and route selection indicates that the model is versatile and flexible enough to be used in novel hydroclimatological conditions.
Sandy beaches are important resources providing recreation, tourism, habitat, and coastal protection. They evolve over various time scales due to local winds, waves, storms, and changes in sea level. A common method used to monitor change in sandy beaches is to measure the movement of the shoreline over time. Typically, the rate of change is estimated by fitting a linear regression through a time series of shoreline positions. To best manage the valuable resources within a coastal environment, accurate forecasts of shoreline position are needed. A simple way to estimate future shoreline position is to extrapolate a linear regression into the future, this method is often used to establish management guidelines like construction setback lines. A more recently developed shoreline forecasting technique utilizes the Kalman filter to assimilate shoreline data and modify the linear regression. This paper calculates the uncertainty and accuracy of both the extrapolated linear regression and Kalman filter forecasting methods for 10- and 20-year hindcasts using data collected at five diverse study areas. These data are inherently sparse (8–10 measurements per location, collected over 150 years) and are representative of the observed historical data available for the continental United States for this timeframe. Both methods produced similar results and had regionally averaged forecast accuracies of 5–16 m. We determined that the inaccuracy of the forecasts is largely due to the effects of shorter time scale variability. This variability is roughly proportional to the standard error of the linear regression, which is a useful measure of forecast uncertainty.
Highly pathogenic avian influenza virus (HPAIV) H5N1 was introduced in North America in late 2021 through trans-Atlantic pathways via migratory birds. These introductions have resulted in an unprecedented epizootic, a widespread disease event in animals, heavily affecting poultry, wild birds, and recently mammals. The North American incursions occurred during the largest epidemic season (2021–2022) in Europe where H5N1 may now be endemic (i.e., continuously present). The continuing outbreak includes expansion into Mexico, Central and South America beginning in late 2022. Here, we provide an overview of the Eurasian origin H5N1 introduction to the Americas, including a significant shift in virus dynamics and severe disease in wild birds. Then, to investigate the global changes in confirmed detections in wild birds and poultry across time and geographic regions, we analyzed FAO's EMPRES-i + database. To examine the 2021 introduction and spread in North American wild birds and poultry, we collated publicly available data across USA and Canadian federal sources. Based on our assessment, the unique magnitude of the North American H5N1 spread indicates the need for effective decision framing to prioritize management needs and scientific inquiry, particularly for species at risk and interface areas for wildlife, poultry, and humans. We illustrate the rapidly occurring and likely increasing detrimental effects that this One Health issue has on wildlife, agriculture, and potentially human health, and we offer a reframing of HPAIV disease response towards a decision analytical context to guide scientific prioritization as a potentially valuable change in focus.
Future water use was projected for public-water systems in Tennessee. Water-use information was compiled for Tennessee for 2010, and projections were made to 2020 and 2030. The water-use models were based on two primary datasets: baseline water-use information for 2010 for Tennessee and projected population in Tennessee.
Population and water withdrawals in Tennessee are expected to increase through 2030. Because population served is projected to increase by about 1 million people during 2010 to 2030, the supply of finished water to meet demand in Tennessee is projected to increase from 921 to 1,137 million gallons per day, or 23 percent. The residential, commercial, and industrial water use, and treatment and nonrevenue water sectors of public supply are about 37, 32, and 30 percent, respectively, of the total water demand in Tennessee during 2010, 2020, and 2030.
In West Tennessee, public-supply water use is 26, 26, and 24 percent of the total water demand in Tennessee during 2010, 2020, and 2030, respectively. From 2010 to 2030, public-supply water use in West Tennessee is projected to increase 13 percent. In Middle Tennessee, public-supply water use is 38, 39, and 41 percent of the total water demand in Tennessee during 2010, 2020, and 2030, respectively. From 2010 to 2030, public-supply water use in Middle Tennessee is projected to increase 33 percent. In East Tennessee, public-supply water use is 36, 36, and 35 percent of the total water demand in Tennessee during 2010, 2020, and 2030, respectively. From 2010 to 2030, public-supply water use in East Tennessee is projected to increase 21 percent.
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\"}}]}","contact":"Director, Lower Mississippi-Gulf Water Science Center
U.S. Geological Survey
640 Grassmere Park, Suite 100
Nashville, TN 37211
We present new X-ray fluorescence compositions of 27 core samples from Phase 3, Hole G of the San Andreas Fault Observatory at Depth, nearly doubling the published dataset for the core. The new analyses consist of major and trace element compositions and the first published data for rare earth elements from Hole G. Whole-rock compositions were obtained to further the analysis of active geochemical processes within the creeping section of the San Andreas Fault in central California. In this report, we plot the new data along with previously published analyses to illustrate some of the compositional features of the Hole G core and to relate them to the core mineralogy.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/ofr20231019","usgsCitation":"Moore, D.E., and Bradbury, K.K., 2023, Chemical characterization of San Andreas Fault Observatory at Depth (SAFOD) Phase 3 core: U.S. Geological Survey Open-File Report 2023–1019, 15 p., https://doi.org/10.3133/ofr20231019.","productDescription":"iv, 15 p.","numberOfPages":"15","onlineOnly":"Y","ipdsId":"IP-142575","costCenters":[{"id":237,"text":"Earthquake Science Center","active":true,"usgs":true}],"links":[{"id":416448,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/2023/1019/ofr20231019.pdf","text":"Report","size":"10 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":499770,"rank":3,"type":{"id":36,"text":"NGMDB Index Page"},"url":"https://ngmdb.usgs.gov/Prodesc/proddesc_114706.htm","linkFileType":{"id":5,"text":"html"}},{"id":416447,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/of/2023/1019/covrthb.jpg"}],"contact":"Earthquake Science Center
U.S. Geological Survey
350 N. Akron Road
Moffett Field, CA 94035
Amaranthus pumilus (seabeach amaranth) is a federally threatened plant species that has been the focus of restoration efforts at Assateague Island National Seashore (ASIS). Despite several years with strong population numbers prior to 2010, monitoring efforts have revealed a significant decline in the seabeach amaranth population since that time, the causes of which have been unclear. To examine potential causes for the population decreases, and to help inform management practices for the future, we first evaluated 20 years of plant population data and three seasons of physical landscape characteristics of seabeach amaranth sites spanning the period of decline to assess how these may have contributed to decreases in habitat. Plant population trends, grazing data, and precipitation data indicate the population declines coincided with severe storms and periods of drought. Furthermore, we found that plants tended to occur at sites on portions of ASIS that were lower elevation on narrower regions of the island than sites where plants were not observed. Secondly, using two different data sampling schemes, we developed Bayesian networks to calculate probabilities of habitat and evaluate the importance of different variables, particularly morphologic metrics, included in the Bayesian networks. Model analyses showed that variables capturing the presence of, and proximity to, the seed bank were important for accurate hindcasts, and that specific barrier-island morphologies tended to occur at sites where seabeach amaranth was observed. More specifically, favorable habitat sites tended to be those more likely to experience overwash during high-water events, consistent with the long-held observations that the plants tend to occur in disturbance-prone settings. Model outputs provide spatially explicit maps of relative habitat suitability and helped to identify high-priority areas for amaranth protection. The modeling effort may also assist in determining the management actions most likely to result in the preservation of a long-term sustainable population.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/sir20235034","collaboration":"Prepared in cooperation with U.S. National Park Service, Assateague Island National Seashore","programNote":"Coastal and Marine Hazards and Resources Program","usgsCitation":"Gutierrez, B.T., and Lentz, E.E., 2023, Developing a habitat model to support management of threatened seabeach amaranth (Amaranthus pumilus) at Assateague Island National Seashore, Maryland and Virginia: U.S. Geological Survey Scientific Investigations Report 2023–5034, 62 p., https://doi.org/10.3133/sir20235034.","productDescription":"Report: viii, 62 p.; 2 Data Releases","numberOfPages":"62","onlineOnly":"Y","additionalOnlineFiles":"N","ipdsId":"IP-138169","costCenters":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":500902,"rank":8,"type":{"id":36,"text":"NGMDB Index Page"},"url":"https://ngmdb.usgs.gov/Prodesc/proddesc_114696.htm","linkFileType":{"id":5,"text":"html"}},{"id":416084,"rank":7,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9GKXN3H","text":"USGS data release","linkHelpText":"Seabeach amaranth presence-absence and barrier island geomorphology metrics as relates to shorebird habitat for Assateague Island National Seashore—2008, 2010, and 2014"},{"id":416083,"rank":6,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9IZMQ1B","text":"USGS data release","linkHelpText":"Assateague Island seabeach amaranth survey data—2001 to 2018"},{"id":416078,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/sir/2023/5034/coverthb.jpg"},{"id":416081,"rank":4,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/sir/2023/5034/sir20235034.XML"},{"id":416082,"rank":5,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/sir/2023/5034/images/"},{"id":416079,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/sir/2023/5034/sir20235034.pdf","text":"Report","size":"14.8 MB","linkFileType":{"id":1,"text":"pdf"},"description":"SIR 2023-5034"},{"id":416080,"rank":3,"type":{"id":39,"text":"HTML Document"},"url":"https://pubs.usgs.gov/publication/sir20235034/full","text":"Report","linkFileType":{"id":5,"text":"html"},"description":"SIR 2023-5034"}],"country":"United States","state":"Maryland, Virginia","otherGeospatial":"Assateague Island National Seashore","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -75.404961539858,\n 37.96286804133118\n ],\n [\n -75.43790635269107,\n 37.87190276298624\n ],\n [\n -75.41868854520543,\n 37.83288321389344\n ],\n [\n -75.3280903099138,\n 37.813365696066924\n ],\n [\n -75.18532945430236,\n 37.95204474129373\n ],\n [\n -75.11943982863623,\n 38.09046248604372\n ],\n [\n -75.07002260938577,\n 38.23940103731053\n ],\n [\n -75.06727720831641,\n 38.334217385797814\n ],\n [\n -75.08649501580261,\n 38.39664223886004\n ],\n [\n -75.15787544360805,\n 38.37297018430121\n ],\n [\n -75.25670988210835,\n 38.245869722482354\n ],\n [\n -75.28690929387204,\n 38.12502605709048\n ],\n [\n -75.37201672702491,\n 37.9780179817395\n ],\n [\n -75.404961539858,\n 37.96286804133118\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director, Woods Hole Coastal and Marine Science Center
U.S. Geological Survey
384 Woods Hole Road Quissett Campus
Woods Hole, MA 02543-1598
Integrating tracking technology and molecular approaches provides a comprehensive picture of contemporary and evolutionary mechanisms promoting connectivity. We used mitochondrial DNA and double digest restriction-site associated DNA (ddRAD) sequencing combined with satellite telemetry to investigate the connectivity of geographically disparate breeding populations of a declining boreal shorebird, the lesser yellowlegs (Tringa flavipes). We were able to track 33 individuals on their round-trip migrations to Central and South America and back to the boreal wetlands of North America. Nearly all (93%) adults captured on the breeding grounds returned to within 5 km of the original capture site, with a median dispersal distance of 629 m. While our telemetry data revealed limited breeding dispersal in adults, genetic data uncovered significant interconnectedness across the species’ range. Very little genetic structure was estimated at ddRAD autosomal (ΦST = 0.001), Z-linked (ΦST = 0.001), and mtDNA loci (ΦST = 0.020), and maximum likelihood-based clustering methods placed all individuals in a single cluster regardless of capture location, indicating the species is panmictic. Our data indicate that large-scale juvenile dispersal is the main mechanism maintaining connectivity in this species, resulting in the absence of genomic structure.
","language":"English","publisher":"MDPI","doi":"10.3390/d15050595","usgsCitation":"Christie, K., Wilson, R., Johnson, J., Friis, C., Harwood, C., McDuffie, L.A., Nol, E., and Sonsthagen, S.A., 2023, Movement and genomic methods reveal mechanisms promoting connectivity in a declining shorebird: The lesser yellowlegs: Diversity, v. 15, 595, 16 p., https://doi.org/10.3390/d15050595.","productDescription":"595, 16 p.","ipdsId":"IP-149982","costCenters":[{"id":198,"text":"Coop Res Unit Atlanta","active":true,"usgs":true}],"links":[{"id":443703,"rank":0,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.3390/d15050595","text":"Publisher Index Page"},{"id":432340,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"Canada, United States","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n 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-78.59286401382221,\n 53.213119625415345\n ],\n [\n -79.796842410287,\n 51.58530529480413\n ],\n [\n -82.16812268307521,\n 54.98614649169525\n ],\n [\n -94.65739223478931,\n 59.48497356409462\n ],\n [\n -96.74379033321011,\n 65.60027490091005\n ],\n [\n -137.15626298561665,\n 69.02662634861974\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"15","noUsgsAuthors":false,"publicationDate":"2023-04-26","publicationStatus":"PW","contributors":{"authors":[{"text":"Christie, Katherine","contributorId":340821,"corporation":false,"usgs":false,"family":"Christie","given":"Katherine","affiliations":[{"id":81671,"text":"Alaska Department of Fish and Game, Threatened","active":true,"usgs":false}],"preferred":false,"id":907584,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Wilson, Robert E.","contributorId":340822,"corporation":false,"usgs":false,"family":"Wilson","given":"Robert E.","affiliations":[{"id":16610,"text":"University of Nebraska-Lincoln","active":true,"usgs":false}],"preferred":false,"id":907585,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Johnson, James A.","contributorId":340823,"corporation":false,"usgs":false,"family":"Johnson","given":"James A.","affiliations":[{"id":40296,"text":"United States Fish and Wildlife Service","active":true,"usgs":false}],"preferred":false,"id":907586,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Friis, Christian","contributorId":340824,"corporation":false,"usgs":false,"family":"Friis","given":"Christian","affiliations":[{"id":36681,"text":"Environment and Climate Change Canada","active":true,"usgs":false}],"preferred":false,"id":907587,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Harwood, Christopher","contributorId":340825,"corporation":false,"usgs":false,"family":"Harwood","given":"Christopher","affiliations":[{"id":36188,"text":"U.S. Fish and Wildlife Service","active":true,"usgs":false}],"preferred":false,"id":907588,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"McDuffie, Laura Anne 0000-0003-2071-7204","orcid":"https://orcid.org/0000-0003-2071-7204","contributorId":299040,"corporation":false,"usgs":true,"family":"McDuffie","given":"Laura","email":"","middleInitial":"Anne","affiliations":[{"id":117,"text":"Alaska Science Center Biology WTEB","active":true,"usgs":true}],"preferred":true,"id":907589,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Nol, Erica","contributorId":340826,"corporation":false,"usgs":false,"family":"Nol","given":"Erica","affiliations":[{"id":36679,"text":"Trent University","active":true,"usgs":false}],"preferred":false,"id":907590,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Sonsthagen, Sarah A. 0000-0001-6215-5874 ssonsthagen@usgs.gov","orcid":"https://orcid.org/0000-0001-6215-5874","contributorId":3711,"corporation":false,"usgs":true,"family":"Sonsthagen","given":"Sarah","email":"ssonsthagen@usgs.gov","middleInitial":"A.","affiliations":[{"id":117,"text":"Alaska Science Center Biology WTEB","active":true,"usgs":true},{"id":114,"text":"Alaska Science Center","active":true,"usgs":true}],"preferred":true,"id":907591,"contributorType":{"id":1,"text":"Authors"},"rank":8}]}} ,{"id":70246285,"text":"70246285 - 2023 - Challenges and solutions for automated avian recognition in aerial imagery","interactions":[],"lastModifiedDate":"2023-09-06T16:14:37.067823","indexId":"70246285","displayToPublicDate":"2023-04-26T06:52:57","publicationYear":"2023","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":5347,"text":"Remote Sensing in Ecology and Conservation","active":true,"publicationSubtype":{"id":10}},"title":"Challenges and solutions for automated avian recognition in aerial imagery","docAbstract":"Remote aerial sensing provides a non-invasive, large geographical-scale technology for avian monitoring, but the manual processing of images limits its development and applications. Artificial Intelligence (AI) methods can be used to mitigate this manual image processing requirement. The implementation of AI methods, however, has several challenges: (1) imbalanced (i.e., long-tailed) data distribution, (2) annotation uncertainty in categorization, and (3) dataset discrepancies across different study sites. Here we use aerial imagery data of waterbirds around Cape Cod and Lake Michigan in the United States to examine how these challenges limit avian recognition performance. We review existing solutions and demonstrate as use cases how methods like Label Distribution Aware Marginal Loss with Deferred Re-Weighting, hierarchical classification, and FixMatch address the three challenges. We also present a new approach to tackle the annotation uncertainty challenge using a Soft-fine Pseudo-Label methodology. Finally, we aim with this paper to increase awareness in the ecological remote sensing community of these challenges and bridge the gap between ecological applications and state-of-the-art computer science, thereby opening new doors to future research.
Colorado Pikeminnow Ptychocheilus lucius, the Colorado River’s top native predatory fish, was historically distributed from the Gulf of California delta to the upper reaches of the Green, Colorado, and San Juan rivers in the Colorado River basin in the Southwestern US. In recent decades Colorado Pikeminnow population abundance has declined, primarily due to predation by warmwater nonnative fish and habitat modification following dam construction. Small, reproducing populations remain in the Green and upper Colorado rivers, but their current population trajectory is declining and the San Juan River population is maintained primarily through stocking. As such, establishment of an additional population could aid recovery efforts and increase the species’ resilience and population redundancy. The Colorado River in Grand Canyon once supported Colorado Pikeminnow, but until recently habitat suitability in this altered reach was considered low due to a depressed thermal regime and abundant nonnative predators. Climate change and ongoing drought has presented an opportunity to evaluate the feasibility of native fish restoration in a system where declining reservoir storage has led to warmer releases and re-emergence of riverine habitat. These changes in the physical attributes of the river have occurred in concert with a system-wide decline in nonnative predators. Conditions ten years ago were not compatible with reintroduction feasibility in Grand Canyon; however, due to rapidly changing conditions an expert Science Panel was convened to evaluate whether the physical and biological attributes of this reach could now support various life stages of Colorado Pikeminnow. Here, we report on the evaluation process and outcome from the Science Panel, which developed a science-based recommendation to the U.S. Fish and Wildlife Service on reintroduction feasibility. The Science Panel concluded that current habitat attributes in Grand Canyon could satisfy some, but perhaps not all, Colorado Pikeminnow life history requirements. This reach has the potential to support adult and sub-adult growth, foraging, migrations, and spawning, but low juvenile survival may limit recruitment. However, populations of other native species are successfully reproducing and increasing in western Grand Canyon, even in areas once considered suboptimal habitat. Should managers decide to move to the next phase of this process, actions such as experimental stocking and monitoring, telemetry studies, bioenergetics modeling, and laboratory-based research may provide additional information to further evaluate a potential reintroduction effort in this rapidly changing but highly altered system.
Chromium concentrations in rock and aquifer material in Hinkley and Water Valleys in the Mojave Desert, 80 miles northeast of Los Angeles, California, are generally low compared to the average chromium concentration of 185 milligrams per kilogram (mg/kg) in the average bulk continental crust. Chromium concentrations in felsic, coarse-textured “Mojave-type” deposits, composed of Mojave River stream (alluvium) and lake-margin (beach) deposits sourced from the Mojave River, are as low as 5 mg/kg, with a median concentration of 23 mg/kg in aquifer materials adjacent to the screened intervals of sampled wells. The most abundant chromium-containing mineral within aquifer materials in Hinkley and Water Valleys is magnetite. Magnetite is resistant to weathering, and about 90 percent of chromium remains within unweathered mineral grains. However, chromium-containing hornblende diorite and basalt are present in surrounding uplands, and chromium-containing actinolite is present within some aquifer materials.
Although geologic abundance of chromium is clearly important, hexavalent chromium, Cr(VI), concentrations in alkaline oxic groundwater are related to additional factors. Hexavalent chromium concentrations in groundwater are influenced by a combination of processes including (1) mineralogy and the weathering rates of chromium-containing minerals; (2) texture of aquifer deposits; (3) accumulation of chromium weathered from minerals within surface coatings on mineral grains; (4) oxidation of accumulated Cr(III) to Cr(VI) in the presence of manganese oxides (Mn oxides), including the abundance and oxidation states of those Mn oxides; (5) pH-dependent desorption of chromium from coatings on the surfaces of mineral grains into groundwater during appropriate aqueous geochemical conditions; and (6) age (time since recharge) of groundwater. The pH of groundwater increases with groundwater age (time since recharge) as a result of silicate weathering, and desorption of Cr(VI) from aquifer deposits increases with increasing pH as long as groundwater remains oxic. In the absence of the detailed geologic, geochemical, and hydrologic data collected as part of this study, pH-dependent sorption, evaluated as the Cr(VI) occurrence probability at the measured pH, is an effective indicator of natural or anthropogenic Cr(VI).
The Pacific Gas and Electric Company (PG&E) Hinkley compressor station is used to compress natural gas as it is transported through a pipeline from Texas to California. Between 1952 and 1964, cooling water containing Cr(VI) was discharged to unlined ponds and released into groundwater in unconsolidated aquifers. The extent of groundwater containing evidence of at least some anthropogenic Cr(VI) was 5.5 square miles (mi2) and was estimated using a summative scale incorporating geologic, geochemical, and hydrologic data collected from more than 100 wells between March 2015 and November 2017. The summative-scale Cr(VI) plume extent is larger than the 2.2 mi2 extent of the October–December 2015 (Q4 2015) regulatory Cr(VI) plume but is smaller than the 8.3 mi2 maximum mapped extent of Cr(VI) greater than the interim regulatory Cr(VI) background concentration of 3.1 micrograms per liter (μg/L). The summative-scale Cr(VI) plume is within felsic, low-chromium aquifer material deposited by the Mojave River described as Mojave-type deposits and is within the area covered by the PG&E monitoring well network.
Background Cr(VI) concentrations were calculated using the computer program ProUCL 5.1 as the upper 95-percent tolerance limit, UTL95, using data from wells outside the summative-scale Cr(VI) plume extent collected between April 2017 and March 2018. The overall UTL95 for undifferentiated, unconsolidated deposits in the eastern and western subareas and the northern subarea upgradient of the Mount General fault in Hinkley Valley was 3.8 μg/L; this value is similar to the overall UTL95 value of 3.9 μg/L calculated for Mojave-type deposits in Hinkley and Water Valleys, and is similar to the maximum Cr(VI) concentration of older groundwater in contact with Mojave-type deposits of 3.6 μg/L.
In most cases the overall UTL95 value may be an acceptable Cr(VI) background value near the Cr(VI) plume margin; however, UTL95 values for the various subareas in Hinkley and Water Valleys provide greater resolution of Cr(VI) background that may be important for some purposes. The UTL95 values for undifferentiated, unconsolidated deposits in the eastern, western, and northern subareas upgradient of the Mount General fault were 2.8, 3.8, and 4.8 μg/L, respectively. The UTL95 value of 2.8 μg/L for wells screened in undifferentiated, unconsolidated deposits in the eastern subarea is important for plume management because the Hinkley compressor station and most of the summative-scale Cr(VI) plume are within the eastern subarea. A UTL95 value of 2.3 μg/L was calculated for Mojave-type deposits downgradient from the Hinkley compressor station. This value represents Cr(VI) concentrations that may have been present in that part of the aquifer had Cr(VI) not been released from the Hinkley compressor station, and it reflects coarser textured deposits in this area and the proximity of those deposits to recharge areas along the Mojave River that results in younger (post-1952), less alkaline groundwater than in wells farther downgradient. This value may be a suitable metric for Cr(VI) cleanup goals within the Cr(VI) plume after regulatory updates. A separate UTL95 value of 5.8 μg/L was calculated for mudflat/playa deposits and older groundwater near Mount General in the eastern subarea. The UTL95 values calculated for undifferentiated, unconsolidated deposits in the northern subarea downgradient from the Mount General fault and in Water Valley, including lacustrine (lake) deposits and material eroded from basalt and Miocene deposits, were 9.0 and 6.4 μg/L, respectively.
Hexavalent chromium concentrations in more than 70 domestic wells sampled between January 27 and 31, 2016, ranged from less than the study reporting level of 0.1–4.0 μg/L, with a median concentration of 1.2 μg/L. Hexavalent chromium concentrations in water from domestic wells did not exceed UTL95 values within subareas where the wells were located. Water from 47 percent of domestic wells sampled between January 27 and 31, 2016, had arsenic, uranium, or nitrate concentrations above a maximum contaminant level.
Anthropogenic Cr(VI) within groundwater downgradient from the Hinkley compressor station is treated by PG&E using bioremediation by adding ethanol as a reductant within a volume of aquifer known as the in situ reactive zone (IRZ). Laboratory microcosm studies showed that Cr(VI) is rapidly reduced to Cr(III) with additions of ethanol. Reduced Cr(III) is sorbed and is sequestered into crystalline iron and manganese oxides on the surfaces of mineral grains within the microcosms during a period of several months. Trivalent chromium was reoxidized back to Cr(VI) within 2 weeks of return to oxic (oxygen present) conditions within the microcosms. As much as 10 percent of added Cr was oxidized to Cr(VI) in microcosms prepared using recent Mojave River aquifer material, and as much as 20 percent of added Cr was oxidized to Cr(VI) in microcosms prepared using older Mojave River aquifer material. Less Cr(VI) (less than 3 percent of Cr added before reduction) was released to the aqueous phase, and this release occurred following longer time periods of oxygen exposure. Sequestration of chromium with manganese oxides during reduction facilitates reoxidation of Cr(III) to Cr(VI) under oxic conditions. Future maintenance of anoxic (oxygen absent) conditions would ensure continued sequestration of chromium as Cr(III) within IRZ treated portions of the Cr(VI) plume.
Although Cr(VI) within the summative-scale Cr(VI) plume may have an anthropogenic history associated with releases from the Hinkley compressor station, Cr(VI) concentrations less than the UTL95 values for the various subareas may not require regulatory attention. The regulatory Cr(VI) plume can be updated using the UTL95 values calculated as part of this study. The updated regulatory Cr(VI) plume extent would lie within the summative-scale Cr(VI) plume extent. The authority to establish regulatory Cr(VI) background values, clean-up goals, and future site management practices resides with the Lahontan Regional Water Quality Control Board.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885J","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Izbicki, J.A., Groover, K.D., Seymour, W.A., Miller, D.M., Warden, J.G., and Miller, L.G., 2023, Summary and conclusions, Chapter J of Natural and anthropogenic (human-made) hexavalent chromium Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-J, 55 p., https://doi.org/10.3133/pp1885J.","productDescription":"Report: x, 55 p.; 5 Data Releases","numberOfPages":"55","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":416312,"rank":6,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9CU0EH3","text":"Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California","description":"Groover, K.D., and Izbicki, J.A., 2018, Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9CU0EH3."},{"id":416309,"rank":4,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/j/images"},{"id":416308,"rank":3,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/j/pp1885j.xml"},{"id":416307,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/j/pp1885j.pdf","text":"Report","size":"10 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416306,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/j/covrthb.jpg"},{"id":417468,"rank":10,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"},{"id":416315,"rank":9,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9HUPMG0","text":"Grain size, mineralogic, and trace-element data from field samples near Hinkley, California","description":"Morrison, J.M., Benzel, W.M., Holm-Denoma, C.S., and Bala, S., 2018, Grain size, mineralogic, and trace-element data from field samples near Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9HUPMG0."},{"id":416314,"rank":8,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9U8C82V","text":"Aqueous and solid phase chemistry of sequestration and re-oxidation of chromium in experimental microcosms with sand and sediment from Hinkley, CA","description":"Miller, L.G., Bobb, C., Bennett, S., and Baesman, S.M., 2020, Aqueous and solid phase chemistry of sequestration and re-oxidation of chromium in experimental microcosms with sand and sediment from Hinkley, CA: U.S. Geological Survey data release, https://doi.org/10.5066/P9U8C82V."},{"id":416313,"rank":7,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9BUXAX1","text":"Hydrologic data in Hinkley and Water Valleys, San Bernardino County, California, 2015–2018","description":"Groover, K.D., Izbicki, J.A., Larsen, J.D., Dick, M.C., Nawikas, J., and Kohel, C.A., 2021, Hydrologic data in Hinkley and Water Valleys, San Bernardino County, California, 2015–2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9BUXAX1."},{"id":416311,"rank":5,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9ENBLGY","text":"Optical Petrography, Bulk Chemistry, Microscale Mineralogy/Chemistry, and Bulk/Micron-Scale Solid-Phase Speciation of Natural and Synthetic Solid Phases Used in Chromium Sequestration and Re-oxidation Experiments with Sand and Sediment from Hinkley, CA","description":"Foster, A.L., Wright, E.G., Bobb, C., Choy, D., and Miller, L.G., 2023, Optical petrography, bulk chemistry, micro-scale mineralogy/chemistry, and bulk/micro-scale speciation of solid phases used in chromium sequestration and re-oxidation experiments with sand and sediment from Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9ENBLGY."}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Groundwater containing hexavalent chromium, Cr(VI), downgradient from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert, 80 miles northeast of Los Angeles, California, is undergoing bioremediation using added ethanol as a reductant in a volume of the aquifer defined as the in situ reactive zone (IRZ). This treatment reduces Cr(VI) to trivalent chromium, Cr(III), which is rapidly sequestered by sorption to aquifer particle surfaces and by co-precipitation within iron (Fe) or manganese (Mn) bearing minerals forming in place as reduction proceeds. Successful mitigation of the Cr(VI) plume is projected to require 10–95 years, at which time bioremediation with ethanol will likely cease. This projection assumes that Cr(VI) removal is permanent and that no Cr(III) will oxidize back to Cr(VI) in the event of changing hydrologic conditions that may cause oxygen-rich water to re-enter the IRZ. Laboratory microcosm experiments were done to explore the process of reductive sequestration of Cr(VI) to Cr(III) and the potential for reoxidation of Cr(III) to Cr(VI).
In reductive sequestration experiments, batch microcosms were prepared with aquifer materials collected from sites upgradient of the Cr(VI) regulatory plume. Control microcosms were prepared using Fe- and Mn-coated quartz sand. Unfiltered Mojave River groundwater containing an added tracer of isotopically labeled chromium-50 were reacted with microcosm materials for up to 2 years; during this time, bio-reduction was stimulated by repeated additions of diluted ethanol to maintain reduced conditions within appropriate ranges, avoiding sulfate reducing or methanogenic conditions as much as possible while mimicking field conditions. Analysis of chromium-50, Fe, and Mn obtained by sequential extraction from microcosms harvested (incubation terminated and microcosm contents analyzed) at various times showed that some aqueous chromium (Cr) was sorbed to particle surfaces within hours; reduction to Cr(III) and incorporation into amorphous and crystalline solid phases occurred during the next few months. Amorphous Cr-containing fractions included Fe and Mn hydroxides and organic matter. Ultimately, most of the chromium-50 tracer was present in the less reactive crystalline phase. However, Fe and Mn were broadly distributed at later stages of reduction, and both were spatially co-located with Cr on a micrometer (μm) scale. Solid-phase data collected using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and X-ray absorption spectroscopy (XAS) indicated that some Cr(III) was associated with mixed valence Fe oxides like magnetite and Fe-Mn oxides like jacobsite. Additionally, Cr(III) was observed within several μm of Fe and Mn embedded in clays and in mineral coatings.
To evaluate the potential for reoxidation of Cr(III) to Cr(VI), additional batch microcosms of aquifer materials and mixtures of Fe- and Mn-coated sand were first reduced for more than 1 year and subsequently oxidized for almost 2 years. Hexavalent chromium was formed and was available for release to the aqueous phase during oxidation of all materials; however, the timing and amount of Cr(VI) formed and released varied among substrates. Artificial substrates containing more Mn produced more Cr(VI). Site material characteristic of recent Mojave River deposits contained within the IRZ produced the least Cr(VI) during oxidation, while site materials composed of older Mojave River aquifer material (containing more Mn) produced more Cr(VI). Site material collected from within the IRZ contained more Cr but produced an intermediate amount of Cr(VI) following oxidation. The combined results of microcosm chemistry and solid-phase analyses showed that the nature and locus of Cr(III) sequestration influenced its vulnerability to reoxidation to Cr(VI). It was concluded that co-location of Cr with Mn at later stages of reduction influenced the susceptibility of Cr(III) to reoxidation in microcosms.
Reoxidation of Cr(III) to Cr(VI) was observed in experiments with previously reduced material after just 14 days exposure to oxygen. As much as 10 percent of added Cr was oxidized to Cr(VI) in microcosms prepared using recent Mojave River aquifer material, and as much as 20 percent of added Cr was oxidized to Cr(VI) in microcosms prepared using older Mojave River aquifer material. Less Cr(VI) (less than 3 percent of Cr added before reduction) was released to the aqueous phase, and this release occurred following longer oxygen exposure. Site managers may need to plan for long-term monitoring and the possibility of active maintenance of anoxic conditions within the IRZ to ensure permanent sequestration of Cr after bioremediation with ethanol ceases.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885I","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Miller, L.G., Bobb, C.E., Foster, A.L., Wright, E.G., Bennett, S.C., Groover, K.D., and Izbicki, J.A., 2023, Sequestration and reoxidation of chromium in experimental microcosms, Chapter I of Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-I, 72 p., https://doi.org/10.3133/pp1885I.","productDescription":"Report: xii, 72 p.; 4 Data Releases","numberOfPages":"72","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":417467,"rank":9,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"},{"id":416302,"rank":8,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/i/images"},{"id":416300,"rank":6,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/i/pp1885i.pdf","text":"Report","size":"13 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416299,"rank":5,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/i/covrthb.jpg"},{"id":416298,"rank":4,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9HUPMG0","text":"Grain size, mineralogic, and trace-element data from field samples near Hinkley, California","description":"Morrison, J.M., Benzel, W.M., Holm-Denoma, C.S., and Bala, S., 2018, Grain size, mineralogic, and trace-element data from field samples near Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9HUPMG0."},{"id":416297,"rank":3,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9U8C82V","text":"Aqueous and solid phase chemistry of sequestration and re-oxidation of chromium in experimental microcosms with sand and sediment from Hinkley, CA","description":"Miller, L.G., Bobb, C., Bennett, S., and Baesman, S.M., 2020, Aqueous and solid phase chemistry of sequestration and re-oxidation of chromium in experimental microcosms with sand and sediment from Hinkley, CA: U.S. Geological Survey data release, https://doi.org/10.5066/P9U8C82V."},{"id":416296,"rank":2,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9CU0EH3","text":"Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California","description":"Groover, K.D., and Izbicki, J.A., 2018, Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9CU0EH3."},{"id":416295,"rank":1,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9ENBLGY.","text":"Optical petrography, bulk chemistry, micro-scale mineralogy/chemistry, and bulk/micro-scale speciation of solid phases used in chromium sequestration and re-oxidation experiments with sand and sediment from Hinkley, California","description":"Foster, A.L., Wright, E.G., Bobb, C., Choy, D., and Miller, L.G., 2023, Optical petrography, bulk chemistry, micro-scale mineralogy/chemistry, and bulk/micro-scale speciation of solid phases used in chromium sequestration and re-oxidation experiments with sand and sediment from Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9ENBLGY."},{"id":416301,"rank":7,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/i/pp1885i.xml"}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Hydrologic and geophysical data were collected to support updates to an existing groundwater-flow model of Hinkley Valley, California, in the Mojave Desert about 80 miles northeast of Los Angeles, California. These data provide information on predevelopment (pre-1930) water levels, groundwater recharge, and selected hydrologic properties of aquifer materials.
A predevelopment groundwater-level map, drawn using water-level measurements from 48 wells collected as early as 1918, showed groundwater movement from recharge areas along the Mojave River to evaporative discharge areas near the margin of Harper (dry) Lake in Water Valley. During predevelopment conditions, depth to water ranged from near land surface along the Mojave River to above land surface near Harper (dry) Lake, consistent with flowing wells in Water Valley at that time. Depths to water in much of Hinkley Valley downgradient from the Lockhart fault were less than 20 feet below land surface. By 2017, water-level declines as a result of agricultural pumping, were as much as 60 feet near the Hinkley compressor station.
Areal recharge from infiltration of precipitation on the valley floor is negligible. Average annual recharge as infiltration of runoff from upland drainages to Hinkley and Water Valleys averages 64.7 acre-feet per year. In most years recharge does not occur; in years when it occurs, recharge to Hinkley Valley is typically about 296 acre-feet. In contrast, average recharge as infiltration of streamflow from the Mojave River from 1931 to 2015 was between 13,400 and 17,100 acre-feet per year; in some years recharge from the Mojave River exceeded 100,000 acre-ft. Estimates of predevelopment groundwater movement through Hinkley Gap and groundwater discharge to Harper (dry) Lake ranged from 570 to 1,900 and 820 to 2,460 acre-feet per year, respectively; at the time of this study in 2017, groundwater movement through Hinkley Gap was estimated to be about 83 acre-feet per year.
Hydraulic-conductivity values estimated from slug-test data for 95 monitoring wells ranged from less than 0.1 to 680 feet per day (ft/d); values generally decreased with depth. Median hydraulic-conductivity values calculated from nuclear magnetic resonance (NMR) data for Mojave River alluvium and near-shore lake deposits were 73 and 11 ft/d, respectively; median hydraulic-conductivity values for locally derived alluvium and weathered bedrock were 6 and 2 ft/d, respectively. Hydraulic-conductivity values, estimated from NMR data for formerly saturated deposits overlying the 2017 water table, were as high as 300 ft/d near the Hinkley compressor station. Downgradient from the Hinkley compressor station, formerly saturated deposits had hydraulic-conductivity values of about 150 ft/d, which were higher than values in saturated material. Coarse-textured, permeable material in formerly saturated deposits above the 2017 water table may have allowed groundwater, released from the Hinkley compressor station that may have contained Cr(VI), to move rapidly downgradient.
The Lockhart fault is an impediment to groundwater flow within Hinkley Valley. Groundwater-flow directions from horizontal point-velocity probe data were deflected to the west on the upgradient side of the fault compared to the nominal direction of groundwater flow estimated from water-level data. Younger groundwater was present on the upgradient and downgradient sides of the fault, and older groundwater with unadjusted carbon-14 ages as old as 5,650 years before present was in water from wells within splays of the Lockhart fault, consistent with limited groundwater movement across the fault. As a result, groundwater and Cr(VI) released from the Hinkley compressor station moved to the northwest along the downgradient side of the fault.
Coupled well-bore flow and depth-dependent water-quality data show water from wells C-01 and IW-03 within the Q4 2015 (October–December 2015) regulatory Cr(VI) plume was yielded from thin layers within the aquifer that are composed of well-sorted lake-margin (beach) deposits that likely have high lateral and longitudinal connectivity. Collectively, data show highly permeable deposits above the regional water table and thin permeable deposits within saturated portions of the upper aquifer that may have conducted groundwater and Cr(VI) downgradient when releases from the Hinkley compressor station first occurred.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885H","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Groover, K.D., Izbicki, J.A., Seymour, W.A., Brown, A.N., Bayless, R.E., Johnson, C.D., Pappas, K.L., Smith, G.A., Clark, D.A., Larsen, J., Dick, M.C., Flint, L.E., Stamos, C.L., and Warden, J.G., 2023, Predevelopment water levels, groundwater recharge, and selected hydrologic properties of aquifer materials, Hinkley and Water Valleys, California, Chapter H of Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-H, 64 p., https://doi.org/10.3133/pp1885H.","productDescription":"Report: x, 64 p.; Data Release; 5 Appendixes","numberOfPages":"64","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":417466,"rank":11,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"},{"id":416347,"rank":10,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/h/tables/pp1885h_appendtable_h.1.5.xlsx","text":"Appendix table H 1.5","linkFileType":{"id":3,"text":"xlsx"}},{"id":416346,"rank":9,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/h/tables/pp1885h_appendtable_h.1.4.xlsx","text":"Appendix table H 1.4","linkFileType":{"id":3,"text":"xlsx"}},{"id":416345,"rank":8,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/h/tables/pp1885h_appendtable_h.1.3.xlsx","text":"Appendix table H 1.3","linkFileType":{"id":3,"text":"xlsx"}},{"id":416344,"rank":7,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/h/tables/pp1885h_appendtable_h.1.2.xlsx","text":"Appendix table H 1.2","linkFileType":{"id":3,"text":"xlsx"}},{"id":416343,"rank":6,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/h/tables/pp1885h_appendtable_h.1.1.xlsx","text":"Appendix table H 1.1","linkFileType":{"id":3,"text":"xlsx"}},{"id":416293,"rank":5,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/h/images"},{"id":416291,"rank":3,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/h/pp1885h.pdf","text":"Report","size":"12 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416290,"rank":2,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/h/covrthb.jpg"},{"id":416292,"rank":4,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/h/pp1885h.xml"},{"id":416289,"rank":1,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9BUXAX1","text":"Hydrologic data in Hinkley and Water Valleys, San Bernardino County, California, 2015–2018","description":"Groover, K.D., Izbicki, J.A., Larsen, J.D., Dick, M.C., Nawikas, J., and Kohel, C.A., 2021, Hydrologic data in Hinkley and Water Valleys, San Bernardino County, California, 2015–2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9BUXAX1."}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Hexavalent chromium, Cr(VI), was released between 1952 and 1964 from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station, in the Mojave Desert about 80 miles northeast of Los Angeles, California. Geologic, geochemical, and hydrologic data from more than 100 wells collected between March 2015 and November 2017 were interpreted using a summative-scale analysis to define the extent of anthropogenic (human-made) Cr(VI) in groundwater. The summative scale consisted of eight questions requiring binary (yes or no) answers for each sampled well. The questions were intended to (1) provide a transparent framework for data interpretation in which all stakeholders participated; (2) provide unbiased interpretation of data traceable to numerical measurements; (3) provide a framework that enabled geologic, geochemical, and hydrologic data to be considered collectively; and (4) consolidate different types of data into a simple, easy-to-understand interpretation. When data from each well are scored using questions and metrics within the summative scale, all stakeholders would score each well the same way and would draw the same summative-scale Cr(VI) plume extent.
The areal extent of the summative-scale Cr(VI) plume was 5.5 square miles (mi2); this is larger than the 2.2-mi2 extent of the October–December 2015 (Q4 2015) regulatory Cr(VI) plume but smaller than the 8.3-mi2 maximum mapped extent of Cr(VI) greater than the interim regulatory Cr(VI) background value of 3.1 micrograms per liter (μg/L). The summative-scale Cr(VI) plume is within the area covered by the PG&E monitoring well network and lies within “Mojave-type” deposits composed of low-chromium stream and near-shore lake deposits sourced from the Mojave River. The summative-scale Cr(VI) plume included all shallow wells within the footprint of the Q4 2015 regulatory Cr(VI) plume, but summative-scale scores indicate that anthropogenic Cr(VI) was not present in several wells within the footprint of the regulatory Cr(VI) plume that were screened within the deep zone of the upper aquifer. The summative-scale Cr(VI) plume extent was consistent with mineralogic and geochemical data collected as part of this study that were not used within the summative-scale analysis.
Data from wells outside the summative-scale Cr(VI) plume collected for regulatory purposes from April 2017 through March 2018 were used to estimate Cr(VI) background concentrations as the upper 95-percent tolerance limit (UTL95) in different parts of Hinkley and Water Valleys. The UTL95 values were calculated using the computer program ProUCL 5.1 and are suitable for use by regulatory agencies in support of (1) updating the regulatory Cr(VI) plume extent and management of Cr(VI) near the plume margins, (2) establishing cleanup goals for Cr(VI) within the updated regulatory Cr(VI) plume, and (3) identifying unusual Cr(VI) concentrations outside the regulatory Cr(VI) plume. The nonparametric UTL95 values for wells screened in Mojave-type deposits in the eastern, western, and northern subareas of Hinkley Valley were 3.7, 3.9, and 4.0 μg/L, respectively. The normal UTL95 values for wells screened in undifferentiated, unconsolidated deposits in the eastern and western subareas and the northern subarea upgradient from the Mount General fault were 2.8, 3.8, and 4.8 μg/L, respectively. An overall normal UTL95 value of 3.8 μg/L was calculated for undifferentiated, unconsolidated deposits in these areas. This value is similar to the overall nonparametric UTL95 value of 3.9 μg/L calculated for Mojave-type deposits and similar to the maximum Cr(VI) concentration of older groundwater in contact with Mojave-type deposits of 3.6 μg/L. The provenance of most PG&E monitoring wells is not precisely known, and the UTL95 values for wells screened in undifferentiated, unconsolidated deposits in the different subareas may be more widely applicable for regulatory purposes than the UTL95 values for Mojave-type deposits.
The UTL95 value of 2.8 μg/L for wells screened in undifferentiated, unconsolidated deposits in the eastern subarea is important for plume management because most of the summative-scale Cr(VI) plume is within the eastern subarea. A UTL95 value of 5.8 μg/L was calculated for older (pre-1952) groundwater associated with mudflat/playa deposits in the eastern subarea near Mount General. A UTL95 value of 2.3 μg/L was calculated for Mojave-type deposits within the Cr(VI) plume downgradient from the Hinkley compressor station after regulatory updates. This lower value is consistent with neutral to slightly alkaline, younger (post-1952) groundwater within coarse-textured, low-chromium Mojave-type deposits in this area and may be a suitable metric for Cr(VI) cleanup goals. The UTL95 value of 4.8 μg/L for wells screened in undifferentiated, unconsolidated deposits in the northern subarea upgradient from the Mount General fault provides for possible increases in Cr(VI) concentrations if water levels continue to decline. Downgradient from the Q4 2015 regulatory Cr(VI) plume and the summative-scale Cr(VI) plume, UTL95 values of 9.0 and 6.4 μg/L were calculated for wells screened in undifferentiated, unconsolidated deposits in the northern subarea downgradient from the Mount General fault and for Water Valley, respectively, consistent with different geologic and geochemical conditions in these areas.
The UTL95 values calculated as part of this study provide scientifically defensible estimates of background Cr(VI) concentrations that differ with local geologic, geochemical, and hydrologic conditions in Hinkley and Water Valleys. The regulatory Cr(VI) plume extent can be updated on the basis of these values. The summative-scale Cr(VI) plume extent may contain wells having anthropogenic Cr(VI) concentrations less than the UTL95 values for their respective subareas that may not require regulatory attention, and an updated regulatory Cr(VI) plume extent may be less than the summative-scale Cr(VI) plume extent. The UTL95 values are not background Cr(VI) concentrations for regulatory purposes, and the authority to establish regulatory values resides solely with the Lahontan Regional Water Quality Control Board.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885G","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Izbicki, J.A., Warden, J.G., Groover, K.D., and Seymour, W.A., 2023, Evaluation of natural and anthropogenic (human-made) hexavalent chromium, Chapter G of Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-G, 51 p., https://doi.org/10.3133/pp1885G.","productDescription":"Report: x, 51 p.; 2 Data Releases; 3 Appendixes","numberOfPages":"51","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":417465,"rank":10,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"},{"id":416337,"rank":9,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/g/tables/pp1885g_appendtable_g.2.2.csv","text":"Appendix table 2.2","linkFileType":{"id":7,"text":"csv"}},{"id":416336,"rank":8,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/g/tables/pp1885g_appendtable_g.2.1.csv","text":"Appendix table 2.1","linkFileType":{"id":7,"text":"csv"}},{"id":416335,"rank":7,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/g/tables/pp1885g_appendtable_g.1.1.csv","text":"Appendix table 1.1","linkFileType":{"id":7,"text":"csv"}},{"id":416287,"rank":6,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/g/images"},{"id":416286,"rank":5,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/g/pp1885g.xml"},{"id":416285,"rank":4,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/g/pp1885g.pdf","text":"Report","size":"5 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416284,"rank":3,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/g/covrthb.jpg"},{"id":416283,"rank":2,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9CU0EH3","text":"Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California","description":"Groover, K.D., and Izbicki, J.A., 2018, Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9CU0EH3."},{"id":416282,"rank":1,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9ENBLGY","text":"Optical petrography, bulk chemistry, micro-scale mineralogy/chemistry, and bulk/micro-scale speciation of solid phases used in chromium sequestration and re-oxidation experiments with sand and sediment from Hinkley, California","description":"Foster, A.L., Wright, E.G., , Bobb, C., Choy, D., and Miller, L.G., 2023, Optical petrography, bulk chemistry, micro-scale mineralogy/chemistry, and bulk/micro-scale speciation of solid phases used in chromium sequestration and re-oxidation experiments with sand and sediment from Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9ENBLGY."}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Hexavalent chromium, Cr(VI), was discharged in cooling wastewater to unlined surface ponds from 1952 to 1964 and reached the underlying unconsolidated aquifer at the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert, 80 miles northeast of Los Angeles, California. A suite of environmental tracers was analyzed in water samples collected from more than 100 wells to characterize the source, age, and geochemical evolution of groundwater within and near the Cr(VI) plume in Hinkley and Water Valleys. This information was used to help determine the extent of Cr(VI) associated with releases from the Hinkley compressor station and to identify Cr(VI) associated with natural sources.
The source of water in most wells, indicated by stable oxygen and hydrogen isotope values for water, delta oxygen-18 and delta deuterium, was recharge by infiltration of intermittent surface flows in the Mojave River. With the exception of small flows in 1958, the Mojave River was largely dry between 1952 and 1969. This dry period spans the period of Cr(VI) releases from the Hinkley compressor station; 1952–69 also spans the period of high tritium levels in precipitation resulting from the atmospheric testing of nuclear weapons and, as a consequence, tritium concentrations in groundwater in Hinkley Valley were comparatively low. Groundwater ages (time since recharge) increased downgradient from the Mojave River and with depth. Tritium, measured by helium ingrowth with a study reporting level of 0.05 tritium unit, was detected in water from 51 percent of wells, with detectable tritium as far as 7 miles downgradient from the Mojave River. Tritium concentrations were higher, and tritium/helium-3 groundwater ages younger, in water from wells near the Mojave River and in water from shallower wells downgradient. Agricultural pumping has decreased groundwater levels as much as 60 feet since 1952. As a result of this pumping, some groundwater containing tritium, and presumably anthropogenic Cr(VI), has been removed from the aquifer. The distribution of wells having carbon-14 activities near or greater than 100-percent modern carbon, consistent with post-1952 recharge water, was similar to the distribution of wells containing detectable tritium. Carbon-14 activities as low as 8.9-percent modern carbon, with carbon-14 ages (unadjusted for reactions with aquifer materials) of almost 20,000 years before present (ybp), were sampled in water from some deep wells. Hexavalent chromium concentrations in older groundwater were as high as 11 micrograms per liter but did not exceed 3.6 micrograms per liter in older water from wells completed in “Mojave-type” deposits (composed of felsic Mojave River stream and near-shore lake deposits sourced from the Mojave River); this value may represent an upper limit on Cr(VI) concentrations in groundwater within Mojave-type deposits that likely approximates background Cr(VI) concentrations in the study area. Chlorofluorocarbons were released to the atmosphere and hydrologic cycle as a result of industrial activity beginning in the 1930s. Chlorofluorocarbon data were not generally suitable for groundwater-age dating in Hinkley and Water Valley because of nonatmospheric contributions from local sources.
Strontium-87/86 isotope ratios and stable chromium isotopes, delta chromium-53, provide information on the geochemical evolution of groundwater in the aquifer. Highly radiogenic strontium-87/86 ratios greater than 0.71000 were present in water from wells completed in coarse-textured Mojave-type deposits having low chromium concentrations but were not diagnostic of these materials. Nonradiogenic strontium-87/86 ratios less than 0.70950 were diagnostic of weathered materials in the northern subarea of Hinkley and in Water Valley that were eroded from Miocene (23–5 million ybp) deposits east of the study area. Values for delta chromium-53 ranged from near 0 to 2.8 parts per thousand (‰) difference. The extent of reductive fractionation, mixing with native groundwater, and longitudinal dispersion within the October–December 2015 (Q4 2015) regulatory Cr(VI) plume can be estimated on the basis of the delta chromium-53 isotope composition of groundwater within the plume. Reduction of Cr(VI) to trivalent chromium, Cr(III), can occur in the presence of natural reductants in oxic groundwater. Although not diagnostic of anthropogenic chromium at the concentrations of interest near the Q4 2015 regulatory Cr(VI) plume margin, delta chromium-53 data indicate anthropogenic Cr(VI) within the plume is not conservative and has reacted with aquifer materials; these reactions have removed some anthropogenic Cr(VI) from groundwater.
Environmental tracers, and the distribution of modern (post-1952) and premodern (pre-1952) groundwater, inform understanding of the extent of anthropogenic and naturally occurring Cr(VI) near the Q4 2015 regulatory Cr(VI) plume and the understanding of geochemical processes occurring in and near the margins of the Cr(VI) plume. The oxygen and hydrogen isotope compositions of water, tritium/helium-3 groundwater-age data, and carbon-14 data were used with mineralogy and chemistry data as part of a summative-scale analysis to determine the Cr(VI) plume extent later in this professional paper (chapter G).
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885F","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Warden, J.G., Izbicki, J.A., Sültenfuß, J., Scheiderich, K., and Fitzpatrick, J., 2023, Environmental tracers of groundwater source, age, and geochemical evolution, Chapter F of Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-F, 74 p., https://doi.org/10.3133/pp1885F.","productDescription":"Report: xii, 74 p.; 2 Data Releases; 2 Appendixes","numberOfPages":"74","onlineOnly":"N","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":416331,"rank":8,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/f/tables/pp1885f_appendtable_f.2.1.xlsx","text":"Appendix table 2.1","linkFileType":{"id":3,"text":"xlsx"}},{"id":416277,"rank":3,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/f/covrthb.jpg"},{"id":417464,"rank":9,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"},{"id":416275,"rank":1,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9CU0EH3","text":"Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California","description":"Groover, K.D., and Izbicki, J.A., 2018, Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9CU0EH3."},{"id":416276,"rank":2,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9HUPMG0","text":"Grain size, mineralogic, and trace-element data from field samples near Hinkley, California","description":"Morrison, J.M., Benzel, W.M., Holm-Denoma, C.S., and Bala, S., 2018, Grain size, mineralogic, and trace-element data from field samples near Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9HUPMG0."},{"id":416278,"rank":4,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/f/pp1885f.pdf","text":"Report","size":"8 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416279,"rank":5,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/f/pp1885f.xml"},{"id":416280,"rank":6,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/f/images"},{"id":416330,"rank":7,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/f/tables/pp1885f_appendtable_f.1.1.csv","text":"Appendix table 1.1","linkFileType":{"id":7,"text":"csv"}}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Water samples collected by the U.S. Geological Survey from more than 100 wells between March 2015 and November 2017 in Hinkley and Water Valleys, in the Mojave Desert 80 miles northeast of Los Angeles, California, were analyzed for field parameters, major ions, nutrients, and selected trace elements, including hexavalent chromium, Cr(VI). Water from most wells was alkaline and oxic. The pH ranged from 6.9 in water-table wells near recharge areas along the Mojave River to 9.4 in deeper wells farther downgradient in the northern subarea.
Hexavalent chromium concentrations measured by ion chromatography using U.S. Environmental Protection Agency Method 218.6 and a version of that method used for detection of Cr(VI) concentrations as low as 0.06 micrograms per liter (μg/L), produced results comparable to field speciation with subsequent analyses by graphite furnace atomic absorption spectroscopy (coefficient of determination, R2, of 0.97). Hexavalent chromium concentrations ranged from less than the study reporting level of 0.10 to 2,500 μg/L. The highest concentrations were within the October–December 2015 (Q4 2015) regulatory Cr(VI) plume downgradient from the Hinkley compressor station. Hexavalent chromium concentrations outside the Q4 2015 regulatory Cr(VI) plume were as high as 11 μg/L. Hexavalent chromium concentrations in water from most wells were distributed in a narrow redox potential and pH band within the overlapping chromate ion, CrO42−(aqueous), and manganese-3, Mn(III)(solid), stability fields. The redox potential of water from some wells completed in carbonate-rich mudflat/playa deposits approached the more oxic manganese-4, Mn(IV)(solid), stability field. However, Cr(VI) concentrations in porewater pressure-extracted from Mn(IV)-containing deposits in the eastern subarea did not exceed 3.3 μg/L, and porewater does not appear to be a source of Cr(VI) concentrations greater than this concentration in water from wells in the eastern subarea.
On the basis of comparison with California-wide data, Cr(VI) concentrations at the measured pH were higher than expected for uncontaminated water from wells (1) within the Q4 2015 regulatory Cr(VI) plume, (2) within the eastern subarea nominally crossgradient from the Hinkley compressor station and upgradient from the Q4 2015 regulatory Cr(VI) plume, and (3) from shallow wells in the northern subarea downgradient from the leading edge of the Q4 2015 regulatory Cr(VI) plume. Hexavalent chromium concentrations in alkaline water from wells in the northern subarea of Hinkley Valley and in Water Valley were within ranges expected for uncontaminated water elsewhere in California given their pH and trace-element composition. Hexavalent chromium concentrations were higher than expected on the basis of selected trace-element concentrations that co-occur with Cr(VI) in water from wells within the Q4 2015 regulatory Cr(VI) plume and from wells in the eastern and northern subareas near the plume margins. Hexavalent chromium concentrations did not exceed 4 μg/L in water from domestic wells sampled in Hinkley and Water Valleys and were generally within ranges expected for uncontaminated groundwater given their pH and trace-element composition.
Interpretations derived from Cr(VI) and pH, and from Cr(VI) and selected trace-element concentrations collected between March 2015 and November 2017 were used within a summative-scale analysis to determine the Cr(VI) plume extent (chapter G). However, Cr(VI) background concentrations (chapter G) were calculated from regulatory data collected from selected wells between April 2017 and January 2018.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885E","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Izbicki, J.A., McCleskey, R.B., Burton, C.A., Clark, D.A., and Smith, G.A., 2023, Groundwater chemistry and hexavalent chromium, Chapter E of Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-E, 63 p., https://doi.org/10.3133/pp1885E.","productDescription":"Report: x, 63 p.; Data Release; 3 Appendixes","numberOfPages":"63","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":417463,"rank":9,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"},{"id":416329,"rank":8,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/e/tables/pp1885e_appendtable_e.1.3.xlsx","text":"Appendix table 1.3"},{"id":416328,"rank":7,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/e/tables/pp1885e_appendtable_e.1.2.xlsx","text":"Appendix table 1.2"},{"id":416327,"rank":6,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/e/tables/pp1885e_appendtable_e.1.1.xlsx","text":"Appendix table 1.1"},{"id":416273,"rank":5,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/e/images"},{"id":416272,"rank":4,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/e/pp1885e.xml"},{"id":416271,"rank":3,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/e/pp1885e.pdf","text":"Report","size":"8 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416270,"rank":2,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/e/covrthb.jpg"},{"id":416267,"rank":1,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9CU0EH3","text":"Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California","description":"Groover, K.D., and Izbicki, J.A., 2018, Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9CU0EH3."}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from the Pacific Gas and Electric Company (PG&E) Hinkley compressor station in the Mojave Desert 80 miles northeast of Los Angeles, California. The Pacific Gas and Electric Company has monitored groundwater near Hinkley, California, for Cr(VI) and other constituents since the late 1980s. By June 2017, more than 20,000 samples had been collected and analyzed for Cr(VI) for regulatory purposes. Most Cr(VI) samples were analyzed using the U.S. Environmental Protection Agency (EPA) Method 218.6 with a laboratory reporting level (LRL) of 0.2 micrograms per liter (μg/L). Between July 2012 and June 2017, selected samples were analyzed for low-level Cr(VI) concentrations using a modified version of EPA Method 218.6 with an LRL of 0.06 μg/L. Field-blank data and duplicate samples collected during this period indicate a study reporting level (SRL) of 0.2 μg/L for most analyses and a SRL of 0.12 μg/L for low-level Cr(VI) analyses. The overall precision for Cr(VI) data analyzed by both methods at the interim regulatory Cr(VI) background concentration of 3.1 μg/L was 0.09 μg/L, or about 3 percent.
Hexavalent chromium concentration trends were calculated for 564 monitoring wells for the period from July 2012 through June 2017. Upward Cr(VI) concentration trends were present in water from 102 monitoring wells throughout Hinkley and Water Valleys. Upward Cr(VI) concentration trends in water from wells near the margins of the October–December 2015 (Q4 2015) regulatory Cr(VI) plume (1) within strands of the Lockhart fault east and southeast of the Hinkley compressor station and (2) in water from shallow wells within the northern subarea were consistent with expansion of the Cr(VI) plume in these areas between 2012 and 2017. Upward Cr(VI) concentration trends were widely distributed elsewhere in Hinkley and Water Valleys outside the Q4 2015 regulatory Cr(VI) plume and were commonly associated with declining water levels. These upward trends may result from natural Cr(VI) sources, including movement of Cr(VI) containing groundwater from (1) weathered bedrock, (2) fine-textured deposits, or (3) secondarily oxidized material distributed throughout aquifer deposits. Downward Cr(VI) concentration trends were observed in 146 monitoring wells. Downward trends were largely within the Q4 2015 regulatory Cr(VI) plume and can be attributed to remediation activities downgradient from the Hinkley compressor station. Hexavalent chromium concentration trends also were calculated for 219 domestic wells from July 2012 through June 2017. Upward Cr(VI) concentration trends in 8 domestic wells and downward trends in 23 domestic wells were clustered largely within former residential areas west of the Q4 2015 regulatory Cr(VI) plume. Results of Cr(VI) trend analyses (including upward, downward, and no trend) were used with other data as part of a summative-scale analysis (chapter G) to define the extent of anthropogenic Cr(VI) and natural Cr(VI) within Hinkley and Water Valleys.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885D","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Izbicki, J.A., and Seymour, W.A., 2023, Analyses of regulatory water-quality data, Chapter D of Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-D, 28 p., https://doi.org/10.3133/pp1885D.","productDescription":"Report: viii, 28 p.; 6 Appendixes","numberOfPages":"28","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":417462,"rank":11,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"},{"id":416326,"rank":10,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/d/tables/pp1885d_appendtable_d.1.6.xlsx","text":"Appendix table D.1.6"},{"id":416325,"rank":9,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/d/tables/pp1885d_appendtable_d.1.5.xlsx","text":"Appendix table D.1.5"},{"id":416323,"rank":7,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/d/tables/pp1885d_appendtable_d.1.3.xlsx","text":"Appendix table D.1.3"},{"id":416322,"rank":6,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/d/tables/pp1885d_appendtable_d.1.2.xlsx","text":"Appendix table D.1.2"},{"id":416321,"rank":5,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/d/tables/pp1885d_appendtable_d.1.1.xlsx","text":"Appendix table D.1.1"},{"id":416262,"rank":3,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/d/pp1885d.xml"},{"id":416261,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/d/pp1885d.pdf","text":"Report","size":"9 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416260,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/d/covrthb.jpg"},{"id":416324,"rank":8,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/d/tables/pp1885d_appendtable_d.1.4.xlsx","text":"Appendix table D.1.4"},{"id":416263,"rank":4,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/d/images"}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from a Pacific Gas and Electric Company (PG&E) compressor station in Hinkley, California, in the western Mojave Desert 80 miles northeast of Los Angeles, California. In 2015, the extent of anthropogenic Cr(VI) in groundwater in Hinkley and Water Valleys was uncertain, but some Cr(VI) in groundwater may be naturally occurring from rock and aquifer material.
To evaluate potential sources of natural Cr(VI), chromium and other selected trace-element concentrations were measured by inductively coupled plasma-mass spectrometry (ICP-MS), with multi-acid digestion, on 34 samples of surficial alluvium and core material from Hinkley and Water Valleys, California, and on 2 samples of alluvium from the mafic Sheep Creek fan to the southwest. Chromium concentrations in Hinkley and Water Valleys ranged from 2 to 110 milligrams per kilogram (mg/kg), with a median concentration of 14 mg/kg; concentrations were highest in weathered mafic hornblende diorite associated with Iron Mountain. High chromium concentrations also were present within fine-textured materials and visually abundant iron- and manganese-oxide coatings on the surfaces of mineral grains. For comparison, chromium concentrations as high as 170 mg/kg were measured in mafic alluvium from the Sheep Creek fan. In contrast, chromium concentrations were lowest in Mojave-type deposits (Mojave River stream and lake margin deposits), with a median of 6 mg/kg. Chromium concentrations measured by ICP-MS compared favorably with concentrations measured by portable (handheld) X-ray fluorescence (pXRF; chapter B), on the basis of least-squares regression results and a coefficient of determination (R2) of 0.97.
Minerals in bulk samples and the heavy (dense) mineral fractions isolated from those samples were identified using optical techniques, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Quartz and feldspar were the most abundant minerals, especially within recent and older Mojave River deposits. Chromium concentrations were as high as 1,250 mg/kg in the heavy-mineral fraction, with specific gravity greater than 3.32. Chromium was not commonly detected in the light-mineral fraction, with specific gravity less than 2.85. Most chromium within the heavy-mineral fraction was substituted within magnetite mineral grains less than 100 micrometers (μm) in diameter, and almost no chromite was present within the heavy-mineral fraction. Although magnetite is resistive to weathering, weathering of magnetite to hematite was identified (1) in Miocene materials underlying unconsolidated deposits in the western subarea of Hinkley Valley and (2) in alluvium within Water Valley that contains weathered minerals eroded from Miocene rock. Less-dense, more easily weathered chromium-containing amphiboles, such as actinolite in older Mojave River alluvium and hornblende in locally derived alluvium from Iron Mountain, were identified optically. Magnetite was not identified in weathered hornblende diorite and was less abundant in locally derived materials and in Miocene materials than in Mojave-type deposits. A comparison of ICP-MS data and sequential extraction data shows that approximately 90 percent of chromium in aquifer material within Hinkley and Water Valleys was not extractable and was interpreted to reside within unweathered mineral grains. Most extractable chromium was within the strong acid extractable fraction. Chromium within the weakly sorbed, and specifically sorbed extractable fractions in oxide accumulations within the regulatory Cr(VI) plume is potentially mobile into groundwater with changes in ionic strength or pH.
Although Hinkley and Water Valleys are regionally low in chromium, natural geologic sources of chromium may be present in aquifer materials penetrated by wells completed in (1) weathered hornblende diorite bedrock underlying the western subarea; (2) Miocene deposits underlying the western subarea and unconsolidated material in the northern subarea and Water Valley containing basalt or weathered minerals eroded from Miocene deposits; (3) unconsolidated material containing visually abundant iron- and manganese-oxide coatings on the surfaces of mineral grains that are present near the water table and near lithologic or geologic contacts; and (4) brown clay and mudflat/playa deposits in the northern subarea. Brown clay and mudflat/playa deposits in the eastern subarea near Mount General have a low-chromium, felsic mineralogy similar to Mojave River deposits and do not contain high concentrations of chromium; however, manganese(IV) oxides within these materials may facilitate oxidation of trivalent chromium, Cr(III), to Cr(VI).
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885C","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Groover, K.D., Izbicki, J.A., Benzel, W., Morrison, J., and Foster, A.L., 2023, Chromium in minerals and selected aquifer materials, Chapter C of Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-C, 49 p., https://doi.org/10.3133/pp1885C.","productDescription":"Report: xii, 49 p.; 3 Data Releases; Appendix","numberOfPages":"49","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":416255,"rank":3,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9HUPMG0","text":"Grain size, mineralogic, and trace-element data from field samples near Hinkley, California","description":"Morrison, J.M., Benzel, W.M., Holm-Denoma, C.S., and Bala, S., 2018, Grain size, mineralogic, and trace-element data from field samples near Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9HUPMG0."},{"id":416254,"rank":2,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9CU0EH3","text":"Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California","description":"Groover, K.D., and Izbicki, J.A., 2018, Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9CU0EH3."},{"id":416257,"rank":5,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/c/pp1885c.pdf","size":"7 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416256,"rank":4,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/c/covrthb.jpg"},{"id":416253,"rank":1,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9ENBLGY.","text":"Optical petrography, bulk chemistry, micro-scale mineralogy/chemistry, and bulk/micro-scale speciation of solid phases used in chromium sequestration and re-oxidation experiments with sand and sediment from Hinkley, California","description":"Foster, A.L., Wright, E.G., , Bobb, C., Choy, D., and Miller, L.G., 2023, Optical petrography, bulk chemistry, micro-scale mineralogy/chemistry, and bulk/micro-scale speciation of solid phases used in chromium sequestration and re-oxidation experiments with sand and sediment from Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9ENBLGY."},{"id":416258,"rank":6,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/c/pp1885c.xml"},{"id":416259,"rank":7,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/c/images"},{"id":416320,"rank":8,"type":{"id":3,"text":"Appendix"},"url":"https://pubs.usgs.gov/pp/1885/c/tables/pp1885c_appendtable_c.1.1.xlsx","text":"Appendix Table C.1.1","size":"100 KB","linkFileType":{"id":3,"text":"xlsx"}},{"id":417460,"rank":9,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Between 1952 and 1964, hexavalent chromium, Cr(VI), was released into groundwater from the Pacific Gas and Electric Company (PG&E) compressor station in Hinkley, California, in the western Mojave Desert 80 miles northeast of Los Angeles, California. In 2015, the extent of anthropogenic Cr(VI) in groundwater in Hinkley and Water Valleys was uncertain, and some Cr(VI) in groundwater may be naturally occurring from rock and aquifer material.
On the basis of more than 1,500 portable (handheld) X-ray fluorescence (pXRF) measurements on more than 250 samples of rock, surficial alluvium, and core material from selected wells in Hinkley and Water Valleys, chromium concentrations are commonly low compared to the average bulk continental abundance of 185 milligrams per kilogram (mg/kg). However, chromium concentrations are as high as 530 mg/kg in mafic hornblende diorite that crops out along the western margin of Hinkley Valley in Iron Mountain. Other chromium-containing rocks in the area are either (1) not consistently high in chromium, (2) have limited areal extent, or (3) in the case of basalt, are present only in Water Valley.
Chromium concentrations in core material adjacent to the screened intervals of wells sampled for water chemistry and isotopic composition as part of the U.S. Geological Survey Cr(VI) background study ranged from less than the study reporting level (SRL) of 5 mg/kg to 410 mg/kg, with a median concentration of 23 mg/kg. Chromium concentrations in core material were lower in the eastern subarea and higher in the western and the northern subareas of Hinkley Valley and in Water Valley. The highest chromium concentration in core material was in weathered hornblende diorite bedrock. Chromium concentrations in core material adjacent to the screened interval of sampled wells were log-normally distributed below a threshold of 85 mg/kg, and 3 percent of chromium concentrations were greater than 85 mg/kg. Manganese can oxidize trivalent chromium, Cr(III), to Cr(VI). Similar to chromium, manganese concentrations in core material also were log-normally distributed below a threshold of 970 mg/kg, and 5 percent of manganese concentrations were greater than 970 mg/kg. Both chromium and manganese concentrations were higher in fine-textured core material and in visually abundant iron- and manganese-oxide coatings on the surfaces of mineral grains. High concentrations of chromium and manganese in core material commonly co-occurred. Fine-textured core material, chromium concentrations greater than 85 mg/kg, and manganese concentrations greater than 970 mg/kg in core material adjacent to the screened interval of sampled wells were selected for use as metrics (threshold values) within a summative-scale analysis (SSA) developed to identify natural and anthropogenic Cr(VI) in water from wells later within this professional paper (chapter G).
Principal component analysis (PCA) of 18 elements within surficial alluvium, rock, and core material measured using pXRF shows distinct elemental assemblages associated with (1) older and more recent “Mojave-type” deposits, including alluvium and lake-margin (beach) deposits sourced from the Mojave River, (2) alluvium eroded from mafic rock, including hornblende diorite that crops out on Iron Mountain, (3) alluvium eroded from felsic volcanic and hydrothermal rock that crops out on Mount General along the eastern margin of Hinkley Valley, (4) playa/mudflat and other fine-textured deposits, and (5) material with visually abundant iron- and manganese-oxide coatings. Most wells sampled as part of this study were completed in Mojave-type deposits. Portable (handheld) X-ray fluorescence data measured on core material from those wells do not appear to be different or unusual compared to the magnitude and range of data from the larger Mojave River groundwater basin, and the core material has a low-chromium, felsic composition consistent with a Mojave River origin. In general, the elemental composition of core material from wells was not measurably altered by admixtures with local mafic, felsic volcanic, or hydrothermal source materials; although, where present, admixtures with basalt may contribute chromium to core material.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/pp1885B","collaboration":"Prepared in cooperation with the Lahontan Regional Water Quality Control Board","usgsCitation":"Izbicki, J.A., and Groover, K.D., 2023, Survey of chromium and selected element concentrations in rock, alluvium, and core material, Chapter B of Natural and anthropogenic (human-made) hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California: U.S. Geological Survey Professional Paper 1885-B, 37 p., https://doi.org/10.3133/pp1885B.","productDescription":"Report: viii, 37 p.; 2 Data Releases","numberOfPages":"37","onlineOnly":"N","additionalOnlineFiles":"Y","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":416250,"rank":5,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9CU0EH3","text":"Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California","description":"Groover, K.D., and Izbicki, J.A., 2018, Field portable X-ray fluorescence and associated quality control data for the western Mojave Desert, San Bernardino County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9CU0EH3."},{"id":416249,"rank":4,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/pp/1885/d/images"},{"id":416248,"rank":3,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/pp/1885/b/pp1885b.xml"},{"id":416247,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/pp/1885/b/pp1885b.pdf","text":"Report","size":"8 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416246,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/pp/1885/d/covrthb.jpg"},{"id":416251,"rank":6,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9HUPMG0","text":"Grain size, mineralogic, and trace-element data from field samples near Hinkley, California","description":"Morrison, J.M., Benzel, W.M., Holm-Denoma, C.S., and Bala, S., 2018, Grain size, mineralogic, and trace-element data from field samples near Hinkley, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9HUPMG0."},{"id":417461,"rank":7,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20231043","text":"Open-File Report 2023-1043","linkHelpText":"- Natural and Anthropogenic Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California"}],"country":"United States","state":"California","city":"Hinkley","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116,\n 35.25\n ],\n [\n -117.75,\n 35.25\n ],\n [\n -117.75,\n 34.25\n ],\n [\n -116,\n 34.25\n ],\n [\n -116,\n 35.25\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Director,
California Water Science Center
U.S. Geological Survey
6000 J Street, Placer Hall
Sacramento, California 95819
Louisiana has high coastal wetland loss rates due to natural processes such as subsidence and anthropogenic activities such as construction of river levees and dams, pervasive alteration of surface hydrology by local industries such as oil and gas, and navigation. With the exception of the Atchafalaya River discharge area, most of Louisiana's marsh coastline is retreating and coastal marshes are degrading. In the inactive degrading delta regions, there exists a previously uncharacterized landform referred to colloquially as coastal ‘land bridge’ marshes. Land bridge marshes are saline or brackish marshes fronting large estuarine bays or lakes with sufficient fetch and wave energy to supply high levels of resuspended sediments to the marsh surface. They are generally linear features that are oriented parallel to the coast and the shoreline front retreats landward due to erosion from wave energy. These marshes persist over time vertically due to input of resuspended sediments but are experiencing rapid edge erosion due to wave attack. Comparison of data from Louisiana's Coastal Reference Monitoring System (CRMS) sites show that land bridge marshes have a greater frequency of higher soil surface elevation and higher soil bulk density than non-land bridge marshes. Because land bridges are vertically stable relative to other coastal wetlands, identification of measures to sustain these landscape features is important. Simulations using MarshMorpho2D, a process-based reduced-complexity morphology model, suggest that protection barriers installed on the seaward side of land bridge marshes will attenuate wave energy and, thus, edge erosion. Shoreline protection that can reduce wave energy but still allow sediment input to marshes include living shorelines, rock barriers, and/or breakwaters. Periodic thin layer nourishment of the marsh surface may be necessary to help sustain vertical growth. Further, marsh creation projects directly landward of land bridge marshes may benefit from their protection from waves and as a source of sediment. Consideration of land bridge marshes as distinct marsh types in the State Master Plan and integrated modeling could help to identify measures to sustain these landscape features.
Trace-metal concentrations in sediment and in the clam Limecola petalum (World Register of Marine Species, 2020; formerly reported as Macoma balthica and M. petalum), clam reproductive activity, and benthic macroinvertebrate community structure were investigated in a mudflat 1 kilometer (km) south of the discharge of the Palo Alto Regional Water Quality Control Plant (PARWQCP) in south San Francisco Bay, California. This report includes the data collected by the U.S. Geological Survey (USGS) for January 2020–December 2020 (Cain and others, 2022). These data append to long-term datasets extending back to 1974. A major focus of the report is an integrated description of the 2020 data within the context of the longer, multidecadal dataset. This dataset supports the City of Palo Alto’s Near-Field Receiving- Water Monitoring Program, initiated in 1994.
Silver and copper contamination substantially decreased at the site in the 1980s following the implementation by PARWQCP of advanced wastewater-treatment and source-control measures. Since the 1990s, concentrations of these elements in surface sediments have continued to decrease, although more slowly. For example, from 1994 to 2020, the minimum annual mean silver concentration—0.20 milligram per kilogram (mg/kg)—was observed in multiple years. In 2020, silver concentrations ranged from 0.18 to 0.28 mg/kg. These concentrations are 2 to 3 times higher than the regional background concentration. Presently (2020), sediment-copper concentrations appear to be near the regional background level. Over the same period (1994–2020), sedimentary iron and zinc exhibited modest decreases. Sedimentary aluminum, chromium, mercury, nickel, and selenium have not exhibited any trend. Since 1994, silver and copper concentrations in L. petalum have varied seasonally, apparently in response to a combination of site-specific metal exposures and cyclic growth and reproduction, as reported previously. Seasonal patterns for other elements, including chromium, mercury, nickel, selenium, and zinc, generally were similar in timing and magnitude as those for silver and copper. Downward trends in the silver and zinc concentrations in L. petalum during 1994–2020 were evident and appeared to be related to the general physiological condition of the clam, indicated by a condition index.
Biological effects of elevated silver and copper contamination at the Palo Alto site have been interpreted from data collected during and after the recession of these contaminants. Concentrations of both elements in the soft tissues of L. petalum decreased with sedimentary copper and silver. This pattern was associated with changes in the reproductive activity of L. petalum, as well as the structure of the benthic invertebrate community. Reproductive activity of L. petalum increased as metal concentrations in L. petalum decreased (Hornberger and others, 2000), and presently is stable with almost all animals initiating reproduction in the fall and spawning the following spring. Analyses of the benthic community structure indicate that the infaunal invertebrate community has shifted from one dominated by several opportunistic species when silver and copper exposures were highest to one in which the species abundance is more evenly distributed, a pattern that indicates a more stable community that is subjected to fewer stressors. Importantly, this long-term change is unrelated to other metals and other measured environmental factors, including salinity and sediment composition. In addition, two of the opportunistic species (Ampelisca abdita and Streblospio benedicti) that brood their young and live on the surface of the sediment in tubes have shown a continual decrease in dominance coincident with the decrease in metals. Both species had short-lived rebounds in abundance in 2008, 2009, and 2010 and showed signs of increasing abundance in 2020. Heteromastus filiformis (a subsurface polychaete worm that lives in the sediment, consumes sediment and organic particles residing in the sediment, and reproduces by laying its eggs on or in the sediment) showed a concurrent increase in dominance and, in the last several years before 2008, showed a stable population. H. filiformis abundance increased slightly from 2011 to 2012 and returned to pre-2011 numbers in 2020.
The reproductive mode of most species that were present in 2020 was indicative of species that were capable of movement either as pelagic larvae or as mobile adults. Although oviparous species were lower in number in this group, the authors hypothesize that these species will return slowly as more species move back into the area. The use of functional ecology was highlighted in the 2020 benthic community data, which showed that the animals that have now returned to the mudflat are those that can respond successfully to a physical, nontoxic disturbance. Today, community data show a mix of species that consume the sediment, or filter feed, those that have pelagic larvae that must survive landing on the sediment, and those that brood their young. The long-term recovery observed after the 1970s can be ascribed to the decrease in sediment pollutants.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/ofr20231017","collaboration":"Prepared in cooperation with the City of Palo Alto, California","usgsCitation":"Cain, D.J., Croteau, M.-N., Thompson, J.K., Parchaso, F., Stewart, R., Zierdt Smith, E.L., Shrader, K.H., Kieu, L.H., and Luoma, S.N., 2023, Near-field receiving-water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California—2020: U.S. Geological Survey Open-File Report 2023–1017, 51 p., https://doi.org/10.3133/ofr20231017.","productDescription":"Report: ix, 51 p.; Data Release","numberOfPages":"51","onlineOnly":"Y","ipdsId":"IP-133169","costCenters":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true},{"id":37277,"text":"WMA - Earth System Processes Division","active":true,"usgs":true}],"links":[{"id":416134,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/of/2023/1017/covrthb.jpg"},{"id":416135,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/of/2023/1017/ofr20231017.pdf","text":"Report","size":"3 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416139,"rank":6,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20181107","text":"Open-File Report 2018-1107","linkHelpText":"- Near-field receiving-water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California—2017"},{"id":416136,"rank":3,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P9IBQ23S","text":"Data for monitoring trace metal and benthic community near the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay, California (ver 2.0, November 2022)","description":"Cain, D.J., Croteau, M., Parchaso, F., Stewart, R., Zierdt Smith, E.L., Thompson, J.K., Kieu, L., Turner, M., and Baesman, S.M., 2022, Data for monitoring trace metal and benthic community near the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay, California (ver 2.0, November 2022): U.S. Geological Survey data release, https://doi.org/10.5066/P9IBQ23S."},{"id":416140,"rank":5,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20171135","text":"Open-File Report 2017-1135","linkHelpText":"- Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California; 2016"},{"id":499767,"rank":9,"type":{"id":36,"text":"NGMDB Index Page"},"url":"https://ngmdb.usgs.gov/Prodesc/proddesc_114697.htm","linkFileType":{"id":5,"text":"html"}},{"id":416137,"rank":8,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20211079","text":"Open-File Report 2021-1079","linkHelpText":"- Near-Field Receiving-Water Monitoring of Trace Metals and a Benthic Community Near the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay, California—2019"},{"id":416138,"rank":7,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20191084","text":"Open-File Report 2019-1084","linkHelpText":"- Near-Field Receiving-Water Monitoring of Trace Metals and a Benthic Community Near the Palo Alto Regional Water Quality Control Plant in South San Francisco Bay, California—2018"},{"id":416141,"rank":4,"type":{"id":22,"text":"Related Work"},"url":"https://doi.org/10.3133/ofr20161118","text":"Open-File Report 2016-1118","linkHelpText":"- Near-field receiving water monitoring of trace metals and a benthic community near the Palo Alto Regional Water Quality Control Plant in south San Francisco Bay, California; 2015"}],"country":"United States","state":"California","otherGeospatial":"South San Francisco Bay","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -122.26067527634044,\n 37.52598582053362\n ],\n [\n -122.26067527634044,\n 37.38564942805466\n ],\n [\n -121.8210169399245,\n 37.38564942805466\n ],\n [\n -121.8210169399245,\n 37.52598582053362\n ],\n [\n -122.26067527634044,\n 37.52598582053362\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Contact Information,
Geology, Minerals, Energy, & Geophysics Science Center
Menlo Park, California
U.S. Geological Survey
Building 19, 350 N. Akron Rd.
P.O. Box 158
Moffett Field, CA 94035
We surveyed for Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) along the upper San Luis Rey River near Lake Henshaw in Santa Ysabel, California, in 2022. Surveys were completed at four locations: three downstream from Lake Henshaw, where surveys occurred from 2015 to 2021 (Rey River Ranch [RRR], Cleveland National Forest [CNF], Vista Irrigation District [VID]), and one at VID Lake Henshaw (VLH) that has been surveyed annually since 2018. There were 71 territorial flycatchers detected at 3 locations (RRR, CNF, VLH), and 6 transient flycatchers of unknown subspecies detected at VID and VLH. Downstream from Lake Henshaw, four territorial flycatchers, including two males and two females, were detected at RRR and CNF. In total, two territories were established consisting of two pairs at these locations. At VLH, we detected 67 territorial flycatchers, including 30 males, 34 females, and 3 flycatchers of unknown sex. In total, 40 territories were established, containing 35 pairs (24 monogamous pairings and 5 polygynous groups consisting of 4 males each pairing with 2 different females, and 1 male pairing with 3 different females), and 5 flycatchers of undetermined breeding status (3 males and 2 flycatchers of unknown sex). Brown-headed cowbirds (Molothrus ater; cowbird) were detected at all four survey locations.
Flycatchers used five habitat types in the survey area: (1) mixed willow riparian, (2) willow-cottonwood, (3) willow-oak, (4) willow-ash, and (5) oak-sycamore. Of the flycatcher locations, 83 percent were located in habitat characterized as mixed willow riparian, and 92 percent were in habitat with greater than 95-percent native plant cover. Exotic vegetation was not prevalent in the survey area.
There were 22 nests incidentally located during surveys: 5 were successful, 1 was seen with eggs on the last visit, 10 failed, and the outcome of the remaining 6 nests was unknown. Three of these nests were parasitized by cowbirds. There were 13 juveniles detected at VLH; no juveniles were detected at RRR or CNF.
Five banded flycatchers were detected during surveys, three of which were confirmed to be adults that held territories in previous years. In addition, two flycatchers with a single dark blue federal band, indicating that they were banded as nestlings in a previous demographic study downstream from Lake Henshaw (Howell and others, 2022), were resighted during surveys.
","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/dr1173","programNote":"Ecosystems Mission Area—Species Management Research Program","usgsCitation":"Howell, S.L., and Kus, B.E., 2023, Distribution and abundance of Southwestern Willow Flycatchers (Empidonax traillii extimus) on the upper San Luis Rey River, San Diego County, California—2022 data summary: U.S. Geological Survey Data Report 1173, 12 p., https://doi.org/10.3133/dr1173.","productDescription":"Report: vi, 12 p.; Data Release","numberOfPages":"12","onlineOnly":"Y","ipdsId":"IP-147974","costCenters":[{"id":651,"text":"Western Ecological Research Center","active":true,"usgs":true}],"links":[{"id":416147,"rank":6,"type":{"id":39,"text":"HTML Document"},"url":"https://pubs.usgs.gov/publication/dr1173/full"},{"id":416146,"rank":5,"type":{"id":34,"text":"Image Folder"},"url":"https://pubs.usgs.gov/dr/1173/images"},{"id":416145,"rank":4,"type":{"id":31,"text":"Publication XML"},"url":"https://pubs.usgs.gov/dr/1173/dr1173.xml"},{"id":416144,"rank":3,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/dr/1173/covrthb.jpg"},{"id":416143,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/dr/1173/dr1173.pdf","text":"Report","size":"4 MB","linkFileType":{"id":1,"text":"pdf"}},{"id":416142,"rank":1,"type":{"id":30,"text":"Data Release"},"url":"https://doi.org/10.5066/P96VC5Y4","text":"Southwestern Willow Flycatcher (Empidonax traillii extimus) surveys and nest monitoring in San Diego County, California","description":"Howell, S.L., and Kus, B.E., 2022, Southwestern Willow Flycatcher (Empidonax traillii extimus) surveys and nest monitoring in San Diego County, California: U.S. Geological Survey data release, https://doi.org/ 10.5066/ P96VC5Y4."}],"country":"United States","state":"California","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -116.55,\n 33.21\n ],\n [\n -116.55,\n 33.07\n ],\n [\n -116.41,\n 33.07\n ],\n [\n -116.41,\n 33.21\n ],\n [\n -116.55,\n 33.21\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","contact":"Western Ecological Research Center
U.S. Geological Survey
3020 State University Drive East
Sacramento, California 95819
The proliferation of genomic sequencing approaches has significantly impacted the field of phylogenetics. Target capture approaches provide a cost-effective, fast and easily applied strategy for phylogenetic inference of non-model organisms. However, several existing target capture processing pipelines are incapable of incorporating whole genome sequencing (WGS). Here, we develop a new pipeline for capture and de novo assembly of the targeted regions using whole genome re-sequencing reads. This new pipeline captured targeted loci accurately, and given its unbiased nature, can be used with any target capture probe set. Moreover, due to its low computational demand, this new pipeline may be ideal for users with limited resources and when high-coverage sequencing outputs are required. We demonstrate the utility of our approach by incorporating WGS data into the first comprehensive phylogenomic reconstruction of the freshwater mussel family Margaritiferidae. We also provide a catalogue of well-curated functional annotations of these previously uncharacterized freshwater mussel-specific target regions, representing a complementary tool for scrutinizing phylogenetic inferences while expanding future applications of the probe set.