Anaerobic oxidation of [1,2-14C]vinyl chloride and [1,2-14C]dichloroethene to 14CO2under humic acid-reducing conditions was demonstrated. The results indicate that waterborne contaminants can be oxidized by using humic acid compounds as electron acceptors and suggest that natural aquatic systems have a much larger capacity for contaminant oxidation than previously thought.
","language":"English","publisher":"American Society for Microbiology","doi":"10.1128/AEM.64.8.3102-3105.1998","issn":"00992240","usgsCitation":"Bradley, P., Chapelle, F.H., and Lovley, D.R., 1998, Humic acids as electron acceptors for anaerobic microbial oxidation of vinyl chloride and dichloroethene: Applied and Environmental Microbiology, v. 64, no. 8, p. 3102-3105, https://doi.org/10.1128/AEM.64.8.3102-3105.1998.","productDescription":"4 p.","startPage":"3102","endPage":"3105","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":479730,"rank":2,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://doi.org/10.1128/aem.64.8.3102-3105.1998","text":"External Repository"},{"id":231005,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"64","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3289e4b0c8380cd5e8aa","contributors":{"authors":[{"text":"Bradley, P. M. 0000-0001-7522-8606","orcid":"https://orcid.org/0000-0001-7522-8606","contributorId":29465,"corporation":false,"usgs":true,"family":"Bradley","given":"P. M.","affiliations":[],"preferred":false,"id":387549,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Chapelle, F. H.","contributorId":101697,"corporation":false,"usgs":true,"family":"Chapelle","given":"F.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":387550,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lovley, Derek R.","contributorId":107852,"corporation":false,"usgs":true,"family":"Lovley","given":"Derek","middleInitial":"R.","affiliations":[],"preferred":false,"id":387551,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70020760,"text":"70020760 - 1998 - Benthic sulfate reduction along the Chesapeake Bay central channel. I. Spatial trends and controls","interactions":[],"lastModifiedDate":"2019-02-04T09:28:04","indexId":"70020760","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2663,"text":"Marine Ecology Progress Series","active":true,"publicationSubtype":{"id":10}},"title":"Benthic sulfate reduction along the Chesapeake Bay central channel. I. Spatial trends and controls","docAbstract":"Factors controlling the spatial distribution of benthic sulfate reduction (SR) were investigated at 3 stations [upper (UB), mid (MB) and lower bay (LB)] along the Chesapeake Bay (eastern USA) central channel from early spring through late fall, 1989 to 1994. Annual rates of 0 to 12 cm depth-integrated SR were 0.96, 9.62 and 6.33 mol S m-2 yr-1 for UB, MB and LB, respectively, as calculated from 35SO42- incubations. SR was carbon limited at UB, LB, and at the sediment surface at MB, and SO42- limited at depth at MB. Temperature explained 33 to 68% of the variability in annual rates, with an apparent influence on SR which increased in the seaward direction in surface sediments. We speculate that the enhanced response of SR to temperature in LB surface sediments was linked to seasonal variations in macrofaunal activity associated with temperature. Estimates of reduced-S burial indicated that only 4 to 8% of sulfur reduced annually was buried as Fe-S minerals at MB and LB, with the remainder presumably being reoxidized. In contrast, >50% of the sulfur reduced annually was buried at UB, due to comparatively low SR rates and the high concentration of reactive iron in the oligohaline region. SR mineralized 18 to 32% of the annual primary production. Our results indicate that organic quality may be more important than the absolute quantity of organic loading in dictating the magnitude of benthic SR rates along an estuarine gradient. Spatial trends in SR reflected the combined influence of deposited organic matter quality and quantity, SO42- availability, the presence or absence of benthic macrofauna, overlying water dissolved O2 conditions, reduced-S reoxidation dynamics, and iron-sulfide mineral formation.","language":"English","publisher":"Inter-Research","doi":"10.3354/meps168213","issn":"01718630","usgsCitation":"Marvin-DiPasquale, M., and Capone, D., 1998, Benthic sulfate reduction along the Chesapeake Bay central channel. I. Spatial trends and controls: Marine Ecology Progress Series, v. 168, p. 213-228, https://doi.org/10.3354/meps168213.","productDescription":"16 p.","startPage":"213","endPage":"228","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":479853,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.3354/meps168213","text":"Publisher Index Page"},{"id":231080,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":266005,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.3354/meps168213"}],"volume":"168","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f0c2e4b0c8380cd4a8d1","contributors":{"authors":[{"text":"Marvin-DiPasquale, M. C.","contributorId":6605,"corporation":false,"usgs":true,"family":"Marvin-DiPasquale","given":"M. C.","affiliations":[],"preferred":false,"id":387392,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Capone, D.G.","contributorId":105876,"corporation":false,"usgs":true,"family":"Capone","given":"D.G.","email":"","affiliations":[],"preferred":false,"id":387393,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70020748,"text":"70020748 - 1998 - Reductive dissolution and reactive solute transport in a sewage-contaminated glacial outwash aquifer","interactions":[],"lastModifiedDate":"2019-02-04T10:16:50","indexId":"70020748","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1861,"text":"Ground Water","active":true,"publicationSubtype":{"id":10}},"title":"Reductive dissolution and reactive solute transport in a sewage-contaminated glacial outwash aquifer","docAbstract":"Contamination of shallow ground water by sewage effluent typically contains reduced chemical species that consume dissolved oxygen, developing either a low oxygen geochemical environment or an anaerobic geochemical environment. Based on the load of reduced chemical species discharged to shallow ground water and the amounts of reactants in the aquifer matrix, it should be possible to determine chemical processes in the aquifer and compare observed results to predicted ones. At the Otis Air Base research site (Cape Cod, Massachusetts) where sewage effluent has infiltrated the shallow aquifer since 1936, bacterially mediated processes such as nitrification, denitrification, manganese reduction, and iron reduction have been observed in the contaminant plume. In specific areas of the plume, dissolved manganese and iron have increased significantly where local geochemical conditions are favorable for reduction and transport of these constituents from the aquifer matrix. Dissolved manganese and iron concentrations ranged from 0.02 to 7.3 mg/L, and 0.001 to 13.0 mg/L, respectively, for 21 samples collected from 1988 to 1989. Reduction of manganese and iron is linked to microbial oxidation of sewage carbon, producing bicarbonate and the dissolved metal ions as by-products. Calculated production and flux of CO2 through the unsaturated zone from manganese reduction in the aquifer was 0.035 g/m2/d (12% of measured CO2 flux during winter). Manganese is limited in the aquifer, however. A one-dimensional, reaction-coupled transport model developed for the mildly reducing conditions in the sewage plume nearest the source beds showed that reduction, transport, and removal of manganese from the aquifer sediments should result in iron reduction where manganese has been depleted.","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.1998.tb02832.x","issn":"0017467X","usgsCitation":"Lee, R.W., and Bennett, P., 1998, Reductive dissolution and reactive solute transport in a sewage-contaminated glacial outwash aquifer: Ground Water, v. 36, no. 4, p. 583-595, https://doi.org/10.1111/j.1745-6584.1998.tb02832.x.","productDescription":"13 p.","startPage":"583","endPage":"595","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":230921,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"36","issue":"4","noUsgsAuthors":false,"publicationDate":"2005-12-23","publicationStatus":"PW","scienceBaseUri":"50e4a3e9e4b0e8fec6cdba1f","contributors":{"authors":[{"text":"Lee, R. W.","contributorId":86757,"corporation":false,"usgs":true,"family":"Lee","given":"R.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":387364,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bennett, P.C.","contributorId":24357,"corporation":false,"usgs":true,"family":"Bennett","given":"P.C.","email":"","affiliations":[],"preferred":false,"id":387363,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70020747,"text":"70020747 - 1998 - Hydrologic modeling of two glaciated watersheds in Northeast Pennsylvania","interactions":[],"lastModifiedDate":"2024-05-29T00:06:38.910386","indexId":"70020747","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2529,"text":"Journal of the American Water Resources Association","active":true,"publicationSubtype":{"id":10}},"title":"Hydrologic modeling of two glaciated watersheds in Northeast Pennsylvania","docAbstract":"ABSTRACT: A hydrologic modeling study, using the Hydrologic Simulation Program - FORTRAN (HSPF), was conducted in two glaciated watersheds, Purdy Creek and Ariel Creek in northeastern Pennsylvania. Both watersheds have wetlands and poorly drained soils due to low hydraulic conductivity and presence of fragipans. The HSPF model was calibrated in the Purdy Creek watershed and verified in the Ariel Creek watershed for June 1992 to December 1993 period. In Purdy Creek, the total volume of observed stream-flow during the entire simulation period was 13.36 × 106 m3 and the simulated streamflow volume was 13.82 × 106 m3 (5 percent difference). For the verification simulation in Ariel Creek, the difference between the total observed and simulated flow volumes was 17 percent. Simulated peak flow discharges were within two hours of the observed for 30 of 46 peak flow events (discharge greater than 0.1 m3/sec) in Purdy Creek and 27 of 53 events in Ariel Creek. For 22 of the 46 events in Purdy Creek and 24 of 53 in Ariel Creek, the differences between the observed and simulated peak discharge rates were less than 30 percent. These 22 events accounted for 63 percent of total volume of streamflow observed during the selected 46 peak flow events in Purdy Creek. In Ariel Creek, these 24 peak flow events accounted for 62 percent of the total flow observed during all peak flow events. Differences in observed and simulated peak flow rates and volumes (on a percent basis) were greater during the snowmelt runoff events and summer periods than for other times.
The contribution of hydroxylated atrazine degradation products (HADPs) to the total atrazine load (i.e., atrazine plus stable metabolites) in streams needs to be determined in order to fully assess the impact of atrazine contamination on stream ecosystems and human health. The objectives of this study were (1) to determine the contribution of HADPs to the total atrazine load in streams of nine midwestern states and (2) to discuss the mechanisms controlling the concentrations of HADPs in streams. Stream samples were collected from 95 streams in northern Missouri at preplant and postplant of 1994 and 1995, and an additional 46 streams were sampled in eight midwestern states at postplant of 1995. Samples were analyzed for atrazine, deethylatrazine (DEA), deisopropylatrazine (DIA), and three HADPs. Overall, HADP prevalence (i.e., frequency of detection) ranged from 87 to 100% for hydroxyatrazine (HA), 0 to 58% for deethylhydroxyatrazine (DEHA), and 0% for deisopropylhydroxyatrazine (DIHA) with method detection limits of 0.04−0.10 μg L-1. Atrazine metabolites accounted for nearly 60% of the atrazine load in northern Missouri streams at preplant, with HA the predominant metabolite present. Data presented in this study and a continuous monitoring study are used to support the hypothesis that a combination of desorption from stream sediments and dissolved-phase transport control HADP concentrations in streams.
The impact on ground water quality from increasing fertilizer application rates over the past 40 years is evaluated within a glacial aquifer system beneath a thick unsaturated zone. Ground water ages within the aquifer could not be accurately determined from the measured distribution of 3H and as a result, chlorofluorocarbon (CFC) and 3H/3He dating techniques were applied. Beneath a 25 m thick unsaturated zone, ground water ages based on CFC‐11 concentrations were greater than 3H/3He ground water ages by 6 to 10 years, due to the time lag associated with the diffusion of CFCs through the unsaturated zone. Using the corrected CFC‐11 and 3H/3He ground water ages and the estimated travel time of 3H within the unsaturated zone, the approximate position of ground water recharged since the mid‐1960s was determined. Nitrate concentrations within post mid‐1960s recharge were generally elevated and near or above the drinking water limit of 10 mg‐N/L. In comparison, pre mid‐1960s recharge had nitrate concentrations <2.5 mg‐N/L. The elevated NO3− concentrations in post mid‐1960s recharge are attributed mainly to increasing fertilizer application rates between 1970 and the mid‐ to late 1980s. Anaerobic conditions suitable for denitrifkation are present within pre mid‐1960s recharge indicating that removal of DO is a slow process taking tens of years. Over the next 10 to 20 years, nitrate concentrations at municipal well fields that are currently capturing aerobic ground water recharged near the mid‐1960s are expected to increase because of the higher fertilizer application rates beginning in the 1970s and 1980s.
","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.1998.tb01078.x","issn":"0017467X","usgsCitation":"Johnston, C., Cook, P., Frape, S., Plummer, N., Busenberg, E., and Blackport, R., 1998, Ground water age and nitrate distribution within a glacial aquifer beneath a thick unsaturated zone: Groundwater, v. 36, no. 1, p. 171-180, https://doi.org/10.1111/j.1745-6584.1998.tb01078.x.","productDescription":"10 p.","startPage":"171","endPage":"180","costCenters":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":230997,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"36","issue":"1","noUsgsAuthors":false,"publicationDate":"2005-08-04","publicationStatus":"PW","scienceBaseUri":"505a2aa2e4b0c8380cd5b332","contributors":{"authors":[{"text":"Johnston, C.T.","contributorId":100146,"corporation":false,"usgs":true,"family":"Johnston","given":"C.T.","email":"","affiliations":[],"preferred":false,"id":387101,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cook, P.G.","contributorId":103807,"corporation":false,"usgs":true,"family":"Cook","given":"P.G.","email":"","affiliations":[],"preferred":false,"id":387103,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Frape, S.K.","contributorId":105335,"corporation":false,"usgs":true,"family":"Frape","given":"S.K.","affiliations":[],"preferred":false,"id":387104,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Plummer, Niel 0000-0002-4020-1013 nplummer@usgs.gov","orcid":"https://orcid.org/0000-0002-4020-1013","contributorId":190100,"corporation":false,"usgs":true,"family":"Plummer","given":"Niel","email":"nplummer@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":387100,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Busenberg, Eurybiades ebusenbe@usgs.gov","contributorId":2271,"corporation":false,"usgs":true,"family":"Busenberg","given":"Eurybiades","email":"ebusenbe@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":387099,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Blackport, R.J.","contributorId":100573,"corporation":false,"usgs":true,"family":"Blackport","given":"R.J.","email":"","affiliations":[],"preferred":false,"id":387102,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70046227,"text":"70046227 - 1998 - Structure contours of base of upper Arapahoe aquifer in \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742","interactions":[],"lastModifiedDate":"2013-06-03T13:23:35","indexId":"70046227","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":6,"text":"USGS Unnumbered Series"},"title":"Structure contours of base of upper Arapahoe aquifer in \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742","docAbstract":"This digital geospatial data set consists of structure contours on the base of the upper member of the Arapahoe aquifer. The U.S. Geological Survey developed this data set as part of a project described in the report,\"Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado\" (Robson and others, 1998)","language":"English","publisher":"U.S Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/70046227","usgsCitation":"Rafferty, S., 1998, Structure contours of base of upper Arapahoe aquifer in \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742, Dataset, https://doi.org/10.3133/70046227.","productDescription":"Dataset","costCenters":[],"links":[{"id":273100,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":273097,"type":{"id":16,"text":"Metadata"},"url":"https://water.usgs.gov/GIS/metadata/usgswrd/XML/co_arapbase_ha742.xml"}],"country":"United States","state":"Colorado","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -105.22675297,39.83151222 ], [ -105.22675297,39.91838553 ], [ -105.1413434,39.91838553 ], [ -105.1413434,39.83151222 ], [ -105.22675297,39.83151222 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"51adbae9e4b07c214e64bd29","contributors":{"authors":[{"text":"Rafferty, Sharon","contributorId":99025,"corporation":false,"usgs":true,"family":"Rafferty","given":"Sharon","affiliations":[],"preferred":false,"id":479228,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70046128,"text":"70046128 - 1998 - Location of wells shown in \"Structure, outcrop,, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742","interactions":[],"lastModifiedDate":"2013-05-28T11:24:09","indexId":"70046128","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":6,"text":"USGS Unnumbered Series"},"title":"Location of wells shown in \"Structure, outcrop,, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742","docAbstract":"This digital geospatial data set consists of locations of coal, oil, gas and water wells shown as data points in the report, \"Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado\" (Robson and others, 1998).","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/70046128","usgsCitation":"Rafferty, S., 1998, Location of wells shown in \"Structure, outcrop,, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742, Dataset, https://doi.org/10.3133/70046128.","productDescription":"Dataset","costCenters":[],"links":[{"id":272879,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":272878,"type":{"id":16,"text":"Metadata"},"url":"https://water.usgs.gov/GIS/metadata/usgswrd/XML/co_wells_ha742.xml"}],"country":"United States","state":"Colorado","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -105.25683628,39.2254652 ], [ -105.25683628,40.88667734 ], [ 104.58906752,40.88667734 ], [ 104.58906752,39.2254652 ], [ -105.25683628,39.2254652 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"51a5d1ebe4b0605bc571efd9","contributors":{"authors":[{"text":"Rafferty, Sharon","contributorId":99025,"corporation":false,"usgs":true,"family":"Rafferty","given":"Sharon","affiliations":[],"preferred":false,"id":478974,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70046127,"text":"70046127 - 1998 - Study-area boundary for \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742","interactions":[],"lastModifiedDate":"2013-05-28T11:07:12","indexId":"70046127","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":6,"text":"USGS Unnumbered Series"},"title":"Study-area boundary for \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742","docAbstract":"This digital geospatial data set consists of outlines of the study area in the report \"Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado\" (Robson and others, 1998).","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/70046127","usgsCitation":"Rafferty, S., 1998, Study-area boundary for \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of the Denver Basin, Colorado.\" Hydrologic Atlas 742, Dataset, https://doi.org/10.3133/70046127.","productDescription":"Dataset","costCenters":[],"links":[{"id":272877,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":272874,"type":{"id":16,"text":"Metadata"},"url":"https://water.usgs.gov/GIS/metadata/usgswrd/XML/co_studyarea_ha742.xml"}],"country":"United States","state":"Colorado","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -105.27975774,39.21441296 ], [ -105.27975774,40.75322131 ], [ -104.59333318,40.75322131 ], [ -104.59333318,39.21441296 ], [ -105.27975774,39.21441296 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"51a5d1eee4b0605bc571f010","contributors":{"authors":[{"text":"Rafferty, Sharon","contributorId":99025,"corporation":false,"usgs":true,"family":"Rafferty","given":"Sharon","affiliations":[],"preferred":false,"id":478973,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70046125,"text":"70046125 - 1998 - Structure contours of top of Laramie-Fox Hills aquifer in \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of Denver Basin, Colorado.\" Hydrologic Atlas 742","interactions":[],"lastModifiedDate":"2013-05-28T10:57:01","indexId":"70046125","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":6,"text":"USGS Unnumbered Series"},"title":"Structure contours of top of Laramie-Fox Hills aquifer in \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of Denver Basin, Colorado.\" Hydrologic Atlas 742","docAbstract":"This digital geospatial data set consists of structure contours of the top of the Laramie-Fox Hills aquifer along the Front Range of Colorado. The U.S. Geological Survey developed this data set as part of a project described in the report, \"Structure, Outcrop, and Subcrop of the Bedrock Aquifers Along the Western Margin of the Denver Basin, Colorado\" (Robson and others, 1998).","language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Reston, VA","doi":"10.3133/70046125","usgsCitation":"Rafferty, S., 1998, Structure contours of top of Laramie-Fox Hills aquifer in \"Structure, outcrop, and subcrop of the bedrock aquifers along the western margin of Denver Basin, Colorado.\" Hydrologic Atlas 742, Dataset, https://doi.org/10.3133/70046125.","productDescription":"Dataset","costCenters":[],"links":[{"id":272871,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/usgs_thumb.jpg"},{"id":272870,"type":{"id":16,"text":"Metadata"},"url":"https://water.usgs.gov/GIS/metadata/usgswrd/XML/co_lfhtop_ha742.xml"}],"country":"United States","state":"Colorado","geographicExtents":"{ \"type\": \"FeatureCollection\", \"features\": [ { \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ [ -104.96266486,40.10504503 ], [ -104.96266486,40.88457484 ], [ -104.59900529,40.88457484 ], [ -104.59900529,40.10504503 ], [ -104.96266486,40.10504503 ] ] ] } } ] }","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"51a5d1eee4b0605bc571f009","contributors":{"authors":[{"text":"Rafferty, Sharon","contributorId":99025,"corporation":false,"usgs":true,"family":"Rafferty","given":"Sharon","affiliations":[],"preferred":false,"id":478971,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70020666,"text":"70020666 - 1998 - Aqueous infrared carboxylate absorbances: Aliphatic di-acids","interactions":[],"lastModifiedDate":"2019-02-04T10:18:41","indexId":"70020666","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3463,"text":"Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy","active":true,"publicationSubtype":{"id":10}},"title":"Aqueous infrared carboxylate absorbances: Aliphatic di-acids","docAbstract":"Aqueous attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra of 18 aliphatic di-carboxylic acids are reported as a function of pH. The spectra show isosbestic points and intensity changes which indicate that Beer's law is obeyed, and peak frequencies lie within previously reported ranges for aqueous carboxylates and pure carboxylic acids. Intensity sharing from the symmetric carboxylate stretch is evident in many cases, so that bands which are nominally due to alkyl groups show increased intensity at higher pH. The asymmetric stretch of the HA− species is linearly related to the microscopic acidity constantof the H2A species, with σpK<0.25 log units; this relationship falls on the same line as previously observed for mono-carboxylic acids. The linear relationship applies to the acidity constant of the HA− species only when the two acid groups are well separated (>2 intervening atoms). The results suggest that aqueous ATR-FTIR may be able to estimate `intrinsic' pKa values of carboxylic acids, in addition to providing quantitative estimates of ionization.
The disposal of radioactive wastes in Arctic seas has made it important to understand the processes affecting the accumulation of radionuclides in food webs in coldwater ecosystems. We examined the effects of temperature on radionuclide assimilation and retention by the bioindicator bivalve Macoma balthica using three representative nuclear waste components, 241Am, 57Co, and 137Cs. Experiments were designed to determine the kinetics of processes that control uptake from food and water, as well as kinetic constants of loss. 137Cs was not accumulated in soft tissue from water during short exposures, and was rapidly lost from shell with no thermal dependence. No effects of temperature on 57Co assimilation or retention from food were observed. The only substantial effect of polar temperatures was that on the assimilation efficiency of 241Am from food, where 10% was assimilated at 2 °C and 26% at 12 °C. For all three radionuclides, body distributions were correlated with source, with most radioactivity obtained from water found in the shell and food in the soft tissues. These results suggest that in general Arctic conditions had relatively small effects on the biological processes which influence the bioaccumulation of radioactive wastes, and bivalve concentration factors may not be appreciably different between polar and temperate waters.
Time series incubations were conducted to provide estimates for the size selectivities and rates of protistan grazing that may be occurring in a sandy, contaminated aquifer. The experiments involved four size classes of fluorescently labeled groundwater bacteria (FLB) and 2- to 3-μm-long nanoflagellates, primarily Spumella guttula(Ehrenberg) Kent, that were isolated from contaminated aquifer sediments (Cape Cod, Mass.). The greatest uptake and clearance rates (0.77 bacteria · flagellate−1 · h−1 and 1.4 nl · flagellate−1 · h−1, respectively) were observed for 0.8- to 1.5-μm-long FLB (0.21-μm3 average cell volume), which represent the fastest growing bacteria within the pore fluids of the contaminated aquifer sediments. The 19:1 to 67:1 volume ratios of nanoflagellate predators to preferred bacterial prey were in the lower end of the range commonly reported for other aquatic habitats. The grazing data suggest that the aquifer nanoflagellates can consume as much as 12 to 74% of the unattached bacterial community in 1 day and are likely to have a substantive effect upon bacterial degradation of organic groundwater contaminants.
Paleoclimatic interpretations of the Upper Triassic Chinle Formation (Colorado Plateau) based on plants conflict with those based on the sedimentary rocks. The plants are suggestive of a humid, equable climate, whereas the rocks are more consistent with deposition under highly seasonal precipitation and ground-water conditions. Fossil plant assemblages are limited to the lower members of the Chinle Formation, which were deposited within incised valleys that were cut into underlying Lower to Middle Triassic and older rocks. In contrast, the upper members of the formation, which were deposited across the fluvial plain after the incised valleys were filled, have few preserved fossil plants. The taphonomic characteristics of the plant fossil assemblages, within the stratigraphic and hydrologic context of the incised valley-fill sequence, explain the vertical and lateral distribution of these assemblages. The depositional, hydrological, and near-surface geochemical conditions were more conducive to preservation of the plants. Fossil plant assemblages in fully terrestrial incised-valley fills should be taphonomically biased toward riparian wetland environments. If those assemblages are used to interpret paleoclimate, the paleoclimatic interpretations will also be biased. The bias may be particularly strong in climates such as those during deposition of the Chinle Formation, when the riparian wetlands may reflect local hydrologic conditions rather than regional climate, and should be taken into account when using these types of plant assemblages in paleoclimatic interpretations.
We present results of an intensive sampling program designed to measure weekly changes in ecosystem respiration (oxygen consumption in the water column and sediments) around the 1996 spring bloom in South San Francisco Bay, California, USA. Measurements were made at a shallow site (2 m, where mean photic depth was 60% of the water column height) and a deep site (15 m, mean photic depth was only 20% of the water column). We also estimated phytoplankton primary production weekly at both sites to develop estimates of net oxygen flux as the sum of pelagic production (PP), pelagic respiration (PR) and benthic respiration (BR). Over the 14 wk period from February 5 to May 14, PP ranged from 2 to 210, PR from 9 to 289, and BR from 0.1 to 48 mmol O2 m-2 d-1, illustrating large variability of estuarine oxygen fluxes at the weekly time scale. Pelagic production exceeded total respiration at the shallow site, but not at the deep site, demonstrating that the shallow domains are net autotrophic but the deep domains are net heterotrophic, even during the period of the spring bloom. If we take into account the potential primary production by benthic microalgae, the estuary as a whole is net autotrophic during spring, net heterotrophic during the nonbloom seasons, and has a balanced net metabolism over a full annual period. The seasonal shift from net autotrophy to heterotrophy during the transition from spring to summer was accompanied by a large shift from dominance by pelagic respiration to dominance by benthic respiration. This suggests that changes in net ecosystem metabolism can reflect changes in the pathways of energy flow in shallow coastal ecosystems.
","language":"English","publisher":"Inter-Research","doi":"10.3354/meps172001","issn":"01718630","usgsCitation":"Caffrey, J., Cloern, J., and Grenz, C., 1998, Changes in production and respiration during a spring phytoplankton bloom in San Francisco Bay, California, USA: Implications for net ecosystem metabolism: Marine Ecology Progress Series, v. 172, p. 1-12, https://doi.org/10.3354/meps172001.","productDescription":"12 p.","startPage":"1","endPage":"12","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true},{"id":552,"text":"San Francisco Bay-Delta","active":false,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true},{"id":5079,"text":"Pacific Regional Director's Office","active":true,"usgs":true}],"links":[{"id":479869,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.3354/meps172001","text":"Publisher Index Page"},{"id":231031,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":266006,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.3354/meps172001"}],"country":"United States","state":"California","otherGeospatial":"San Francisco Bay","volume":"172","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f420e4b0c8380cd4bb68","contributors":{"authors":[{"text":"Caffrey, J.M.","contributorId":98750,"corporation":false,"usgs":true,"family":"Caffrey","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":386756,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cloern, J. E.","contributorId":59453,"corporation":false,"usgs":true,"family":"Cloern","given":"J. E.","affiliations":[],"preferred":false,"id":386755,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Grenz, C.","contributorId":40753,"corporation":false,"usgs":true,"family":"Grenz","given":"C.","affiliations":[],"preferred":false,"id":386754,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70020555,"text":"70020555 - 1998 - Development and testing of a contamination potential mapping system for a portion of the General Separations Area, Savannah River Site, South Carolina","interactions":[],"lastModifiedDate":"2017-01-18T12:48:56","indexId":"70020555","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1539,"text":"Environmental Geology","active":true,"publicationSubtype":{"id":10}},"title":"Development and testing of a contamination potential mapping system for a portion of the General Separations Area, Savannah River Site, South Carolina","docAbstract":"A methodology was developed to evaluate and map the contamination potential or aquifer sensitivity of the upper groundwater flow system of a portion of the General Separations Area (GSA) at the Department of Energy's Savannah River Site (SRS) in South Carolina. A Geographic Information System (GIS) was used to integrate diverse subsurface geologic data, soils data, and hydrology utilizing a stack-unit mapping approach to construct mapping layers. This is the first time that such an approach has been used to delineate the hydrogeology of a coastal plain environment. Unit surface elevation maps were constructed for the tops of six Tertiary units derived from over 200 boring logs. Thickness or isopach maps were created for five hydrogeologic units by differencing top and basal surface elevations. The geologic stack-unit map was created by stacking the five isopach maps and adding codes for each stack-unit polygon. Stacked-units were rated according to their hydrogeologic properties and ranked using a logarithmic approach (utility theory) to establish a contamination potential index. Colors were assigned to help display relative importance of stacked-units in preventing or promoting transport of contaminants. The sensitivity assessment included the effects of surface soils on contaminants which are particularly important for evaluating potential effects from surface spills. Hydrogeologic/hydrologic factors did not exhibit sufficient spatial variation to warrant incorporation into contamination potential assessment. Development of this contamination potential mapping system provides a useful tool for site planners, environmental scientists, and regulatory agencies.A methodology was developed to evaluate and map the contamination potential or aquifer sensitivity of the upper groundwater flow system of a portion of the General Separations Area (GSA) at the Department of Energy's Savannah River Site (SRS) in South Carolina. A Geographic Information System (GIS) was used to integrate diverse subsurface geologic data, soils data, and hydrology utilizing a stack-unit mapping approach to construct mapping layers. This is the first time that such an approach has been used to delineate the hydrogeology of a coastal plain environment. Unit surface elevation maps were constructed for the tops of six Tertiary units derived from over 200 boring logs. Thickness or isopach maps were created for five hydrogeologic units by differencing top and basal surface elevations. The geologic stack-unit map was created by stacking the five isopach maps and adding codes for each stack-unit polygon. Stacked-units were rated according to their hydrogeologic properties and ranked using a logarithmic approach (utility theory) to establish a contamination potential index. Colors were assigned to help display relative importance of stacked-units in preventing or promoting transport of contaminants. The sensitivity assessment included the effects of surface soils on contaminants which are particularly important for evaluating potential effects from surface spills. Hydrogeologic/hydrologic factors did not exhibit sufficient spatial variation to warrant incorporation into contamination potential assessment. Development of this contamination potential mapping system provides a useful tool for site planners, environmental scientists, and regulatory agencies.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Environmental Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Springer-Verlag GmbH & Company KG","publisherLocation":"Berlin, Germany","doi":"10.1007/s002540050313","issn":"09430105","usgsCitation":"Rine, J., Berg, R.C., Shafer, J., Covington, E., Reed, J., Bennett, C., and Trudnak, J., 1998, Development and testing of a contamination potential mapping system for a portion of the General Separations Area, Savannah River Site, South Carolina: Environmental Geology, v. 35, no. 4, p. 263-277, https://doi.org/10.1007/s002540050313.","startPage":"263","endPage":"277","numberOfPages":"15","costCenters":[{"id":13634,"text":"South Atlantic Water Science Center","active":true,"usgs":true}],"links":[{"id":231305,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206942,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s002540050313"}],"country":"United States","state":"South Carolina","otherGeospatial":"Savannah River Site","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -81.9854736328125,\n 32.87382044499353\n ],\n [\n -81.9854736328125,\n 33.42341844641943\n ],\n [\n -81.26174926757812,\n 33.42341844641943\n ],\n [\n -81.26174926757812,\n 32.87382044499353\n ],\n [\n -81.9854736328125,\n 32.87382044499353\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"35","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0027e4b0c8380cd4f5fc","contributors":{"authors":[{"text":"Rine, J.M.","contributorId":53145,"corporation":false,"usgs":true,"family":"Rine","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":386682,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Berg, R. C.","contributorId":11673,"corporation":false,"usgs":true,"family":"Berg","given":"R.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":386680,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Shafer, J.M.","contributorId":72995,"corporation":false,"usgs":true,"family":"Shafer","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":386686,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Covington, E.R.","contributorId":58157,"corporation":false,"usgs":true,"family":"Covington","given":"E.R.","email":"","affiliations":[],"preferred":false,"id":386684,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Reed, J.K.","contributorId":38031,"corporation":false,"usgs":true,"family":"Reed","given":"J.K.","email":"","affiliations":[],"preferred":false,"id":386681,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Bennett, C.B.","contributorId":61308,"corporation":false,"usgs":true,"family":"Bennett","given":"C.B.","email":"","affiliations":[],"preferred":false,"id":386685,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Trudnak, J.E.","contributorId":56938,"corporation":false,"usgs":true,"family":"Trudnak","given":"J.E.","email":"","affiliations":[],"preferred":false,"id":386683,"contributorType":{"id":1,"text":"Authors"},"rank":7}]}} ,{"id":70020540,"text":"70020540 - 1998 - Benthic invertebrate distributions in the San Joaquin River, California, in relation to physical and chemical factors","interactions":[],"lastModifiedDate":"2019-02-01T06:15:02","indexId":"70020540","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1169,"text":"Canadian Journal of Fisheries and Aquatic Sciences","active":true,"publicationSubtype":{"id":10}},"title":"Benthic invertebrate distributions in the San Joaquin River, California, in relation to physical and chemical factors","docAbstract":"The invertebrate fauna of nontidal portions of the lower San Joaquin River and its major tributaries is described in relation to water quality and habitat using canonical correspondence analysis, autecological metrics, and indicator species analysis. A large-scale (basin-wide) pattern in community response to salinity (sulfate-bicarbonate type) was detected when standardized, stable substratum was sampled. Community structure, taxa richness, and EPT (ephemeropterans, plecopterans, and trichopterans) richness varied with dissolved solids concentration (55-1700 mg total dissolved solids. L-1), and distributions of many taxa indicated salinity optima. Distinct assemblages associated with either high or low salinity were evident over this range. Large-scale patterns in community structure were unrelated to pesticide distributions. Structure and taxa richness of invertebrate assemblages in sand substratum varied both with salinity and with microhabitat heterogeneity. The benthic fauna generally was dominated by a taxa-poor assemblage of specialized psammophilous species, contributing to a weaker relationship between community structure and water quality than was observed using standardized substratum. Habitat types and associated dominant species were characterized using indicator species analysis. Species assemblages did not vary substantially with irrigation regime or fiver discharge, indicating that structure of invertebrate communities was a conservative measure of water quality.","language":"English","publisher":"Canada Science Publishing ","doi":"10.1139/f97-316","issn":"0706652X","usgsCitation":"Leland, H., and Fend, S., 1998, Benthic invertebrate distributions in the San Joaquin River, California, in relation to physical and chemical factors: Canadian Journal of Fisheries and Aquatic Sciences, v. 55, no. 5, p. 1051-1067, https://doi.org/10.1139/f97-316.","productDescription":"17 p.","startPage":"1051","endPage":"1067","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":231029,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California ","otherGeospatial":"San Joaquin River","volume":"55","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f0bce4b0c8380cd4a8ad","contributors":{"authors":[{"text":"Leland, H.V.","contributorId":82455,"corporation":false,"usgs":true,"family":"Leland","given":"H.V.","email":"","affiliations":[],"preferred":false,"id":386608,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Fend, S.V. 0000-0002-4638-6602","orcid":"https://orcid.org/0000-0002-4638-6602","contributorId":99702,"corporation":false,"usgs":true,"family":"Fend","given":"S.V.","affiliations":[],"preferred":false,"id":386609,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70020518,"text":"70020518 - 1998 - Relation of usage to the occurrence of cotton and rice herbicides in three streams of the Mississippi delta","interactions":[],"lastModifiedDate":"2019-02-04T10:04:31","indexId":"70020518","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1565,"text":"Environmental Science & Technology","onlineIssn":"1520-5851","printIssn":"0013-936X","active":true,"publicationSubtype":{"id":10}},"title":"Relation of usage to the occurrence of cotton and rice herbicides in three streams of the Mississippi delta","docAbstract":"During the 1995 growing season water samples were collected from three streams in the Mississippi delta and were analyzed for selected cotton and rice herbicides and metabolites. The purpose of the study was to relate the use of these herbicides to their occurrence in streams of the delta, to describe how the geochemistry of these herbicides affects their occurrence, and to report the occurrence of selected metabolites. The total concentration of eight herbicides and their metabolites exceeded 5 μg/L throughout most of the growing season with a median total of 15 μg/L. The order of occurrence was molinate > fluometuron > cyanazine > metolachlor > norflurazon > atrazine > prometryn > propanil. The distribution and duration of the total herbicide concentration found in this study are much different from that found in regional studies of herbicides in the U.S. Midwest. In the Midwest, the total herbicide concentration in surface water showed a sharp peak during the spring immediately after application of herbicides to crops, followed by a gradual decrease. In the Mississippi delta, the total herbicide concentration in surface water was more sustained, with multiple peaks due to different application times and postemergent applications to cotton and rice.
A natural-gradient tracer test was conducted in an unconfined sand and gravel aquifer on Cape Cod, Massachusetts. Molybdate was included in the injectate to study the effects of variable groundwater chemistry on its aqueous distribution and to evaluate the reliability of laboratory experiments for identifying and quantifying reactions that control the transport of reactive solutes in groundwater. Transport of molybdate in this aquifer was controlled by adsorption. The amount adsorbed varied with aqueous chemistry that changed with depth as freshwater recharge mixed with a plume of sewage-contaminated groundwater. Molybdate adsorption was strongest near the water table where pH (5.7) and the concentration of the competing solutes phosphate (2.3 micromolar) and sulfate (86 micromolar) were low. Adsorption of molybdate decreased with depth as pH increased to 6.5, phosphate increased to 40 micromolar, and sulfate increased to 340 micromolar. A one-site diffuse-layer surface-complexation model and a two-site diffuse-layer surface-complexation model were used to simulate adsorption. Reactions and equilibrium constants for both models were determined in laboratory experiments and used in the reactive-transport model PHAST to simulate the two-dimensional transport of molybdate during the tracer test. No geochemical parameters were adjusted in the simulation to improve the fit between model and field data. Both models simulated the travel distance of the molybdate cloud to within 10% during the 2-year tracer test; however, the two-site diffuse-layer model more accurately simulated the molybdate concentration distribution within the cloud.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98WR02163","usgsCitation":"Stollenwerk, K.G., 1998, Molybdate transport in a chemically complex aquifer: Field measurements compared with solute-transport model predictions: Water Resources Research, v. 34, no. 10, p. 2727-2740, https://doi.org/10.1029/98WR02163.","productDescription":"14 p.","startPage":"2727","endPage":"2740","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":228233,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Massachusetts","otherGeospatial":"Cape Cod","volume":"34","issue":"10","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a5d27e4b0c8380cd701c3","contributors":{"authors":[{"text":"Stollenwerk, Kenneth G. kgstolle@usgs.gov","contributorId":578,"corporation":false,"usgs":true,"family":"Stollenwerk","given":"Kenneth","email":"kgstolle@usgs.gov","middleInitial":"G.","affiliations":[],"preferred":true,"id":385214,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70020439,"text":"70020439 - 1998 - Preferential flow and transport of nitrate and bromide in claypan soil","interactions":[],"lastModifiedDate":"2019-01-30T09:27:28","indexId":"70020439","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1861,"text":"Ground Water","active":true,"publicationSubtype":{"id":10}},"title":"Preferential flow and transport of nitrate and bromide in claypan soil","docAbstract":"The in situ measurement of water flow and chemical transport through clay pan soils is crucial to understanding potential water contamination from agricultural sources. It is important due to the large areal extent of these soils in agricultural regions of the midwestern United States and because of preferential flow paths caused by desiccation cracks, worms burrowing, and root development. A study plot at the Missouri Management Systems Evaluation Area near Centralia, Missouri, was instrumented to determine the rate of preferential flow of water and transport of NO3−1 fertilizer in the unsaturated zone through a claypan soil using 15N‐NO3−1 and Br‐1 tracers. The areal distribution of preferential flow paths was between 2 and 20% in the topsoil. Gravity lysimeter flow caused by preferential flow through the claypan was as much as 150 times greater than the estimated average rate of vertical recharge. As much as 2.4% of the volume of the soil below the clay pan may be occupied by preferential flow paths.
","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.1998.tb02820.x","issn":"0017467X","usgsCitation":"Kelly, B.P., and Pomes, M., 1998, Preferential flow and transport of nitrate and bromide in claypan soil: Ground Water, v. 36, no. 3, p. 484-494, https://doi.org/10.1111/j.1745-6584.1998.tb02820.x.","productDescription":"11 p.","startPage":"484","endPage":"494","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":231332,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"36","issue":"3","noUsgsAuthors":false,"publicationDate":"2005-12-23","publicationStatus":"PW","scienceBaseUri":"505a821de4b0c8380cd7b8f6","contributors":{"authors":[{"text":"Kelly, B. P.","contributorId":30653,"corporation":false,"usgs":true,"family":"Kelly","given":"B.","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":386221,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Pomes, M.L.","contributorId":84393,"corporation":false,"usgs":true,"family":"Pomes","given":"M.L.","affiliations":[],"preferred":false,"id":386222,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70185696,"text":"70185696 - 1998 - Feldspars as a source of nutrients for microorganisms","interactions":[],"lastModifiedDate":"2019-02-04T07:38:37","indexId":"70185696","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":738,"text":"American Mineralogist","active":true,"publicationSubtype":{"id":10}},"title":"Feldspars as a source of nutrients for microorganisms","docAbstract":"Phosphorus and nitrogen are essential macronutrients necessary for the survival of virtually all living organisms. In groundwater systems, these nutrients can be quite scarce and can represent limiting elements for growth of subsurface microorganisms. In this study we examined silicate sources of these elements by characterizing the colonization and weathering of feldspars in situ using field microcosms. We found that in carbon-rich anoxic groundwaters where P and N are scarce, feldspars that contain inclusions of P-minerals such as apatite are preferentially colonized over similar feldspars without P. A microcline from S. Dakota, which contains 0.24% P2O5 but ,1 mmol/ g NH , was heavily colonized 1 4 and deeply weathered. A similar microcline from Ontario, which has no detectable P or NH , was barren of attached organisms and completely unweathered after one year. An- 1 4 orthoclase (0.28% P2O5, ;1 mmol/g NH ) was very heavily colonized and weathered, 1 4 whereas plagioclase specimens (,0.01% P, ,1 mmmol/g NH ) were uncolonized and 1 4 unweathered. In addition, the observed weathering rates are faster than expected based on laboratory rates. We propose that this system is particularly sensitive to the availability of P, and the native subsurface microorganisms have developed biochemical strategies to aggressively scavenge P (or some other essential nutrient such as Fe31 ) from resistant feldspars. The result of this interaction is that only minerals containing P will be signifi- cantly colonized, and these feldspars will be preferentially destroyed, as the subsurface microbial community scavenges a limiting nutrient.
","language":"English","publisher":"GeoScienceWorld ","doi":"10.2138/am-1998-11-1241","usgsCitation":"Rogers, J., Bennett, P., and Choi, W., 1998, Feldspars as a source of nutrients for microorganisms: American Mineralogist, v. 83, p. 1532-1540, https://doi.org/10.2138/am-1998-11-1241.","productDescription":"9 p.","startPage":"1532","endPage":"1540","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":338423,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"83","noUsgsAuthors":false,"publicationDate":"1998-12-01","publicationStatus":"PW","scienceBaseUri":"58da253be4b0543bf7fda86d","contributors":{"authors":[{"text":"Rogers, J.R.","contributorId":189897,"corporation":false,"usgs":false,"family":"Rogers","given":"J.R.","email":"","affiliations":[],"preferred":false,"id":686422,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bennett, P.C.","contributorId":24357,"corporation":false,"usgs":true,"family":"Bennett","given":"P.C.","email":"","affiliations":[],"preferred":false,"id":686423,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Choi, W.J.","contributorId":189896,"corporation":false,"usgs":false,"family":"Choi","given":"W.J.","email":"","affiliations":[],"preferred":false,"id":686424,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ]}