Topographically distributed energy- and water-balance models can accurately simulate both the development and melting of a seasonal snowcover in the mountain basins. To do this they require time-series climate surfaces of air temperature, humidity, wind speed, precipitation, and solar and thermal radiation. If data are available, these parameters can be adequately estimated at time steps of one to three hours. Unfortunately, climate monitoring in mountain basins is very limited, and the full range of elevations and exposures that affect climate conditions, snow deposition, and melt is seldom sampled. Detailed time-series climate surfaces have been successfully developed using limited data and relatively simple methods. We present a synopsis of the tools and methods used to combine limited data with simple corrections for the topographic controls to generate high temporal resolution time-series images of these climate parameters. Methods used include simulations, elevational gradients, and detrended kriging. The generated climate surfaces are evaluated at points and spatially to determine if they are reasonable approximations of actual conditions. Recommendations are made for the addition of critical parameters and measurement sites into routine monitoring systems in mountain basins.
An analytical method useful for the quantification of a range of pesticides and pesticide degradation products associated with suspended sediments was developed by testing a variety of extraction and cleanup schemes. The final extraction and cleanup methods chosen for use are suitable for the quantification of the listed pesticides using gas chromatography-ion trap mass spectrometry and the removal of interfering coextractable organic material found in suspended sediments. Methylene chloride extraction followed by Florisil cleanup proved most effective for separation of coextractives from the pesticide analytes. Removal of elemental sulfur was accomplished with tetrabutylammonium hydrogen sulfite. The suitability of the method for the analysis of a variety of pesticides was evaluated, and the method detection limits (MDLs) were determined (0.1-6.0 ng/g dry weight of sediment) for 21 compounds. Recovery of pesticides dried onto natural sediments averaged 63%. Analysis of duplicate San Joaquin River suspended-sediment samples demonstrated the utility of the method for environmental samples with variability between replicate analyses lower than between environmental samples. Eight of 21 pesticides measured were observed at concentrations ranging from the MDL to more than 80 ng/g dry weight of sediment and exhibited significant temporal variability. Sediment-associated pesticides, therefore, may contribute to the transport of pesticides through aquatic systems and should be studied separately from dissolved pesticides.
","language":"English","publisher":"Taylor & Francis","doi":"10.1080/02772249909358713","issn":"02772248","usgsCitation":"Bergamaschi, B., Baston, D., Crepeau, K., and Kuivila, K., 1999, Determination of pesticides associated with suspended sediments in the San Joaquin River, California, USA, using gas chromatography-ion trap mass spectrometry: Toxicological and Environmental Chemistry, v. 69, no. 3-4, p. 305-319, https://doi.org/10.1080/02772249909358713.","productDescription":"15 p.","startPage":"305","endPage":"319","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":229168,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"69","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ffbce4b0c8380cd4f37e","contributors":{"authors":[{"text":"Bergamaschi, B.A. 0000-0002-9610-5581","orcid":"https://orcid.org/0000-0002-9610-5581","contributorId":22401,"corporation":false,"usgs":true,"family":"Bergamaschi","given":"B.A.","affiliations":[],"preferred":false,"id":389956,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Baston, D.S.","contributorId":49131,"corporation":false,"usgs":true,"family":"Baston","given":"D.S.","email":"","affiliations":[],"preferred":false,"id":389958,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Crepeau, K.L.","contributorId":9018,"corporation":false,"usgs":true,"family":"Crepeau","given":"K.L.","affiliations":[],"preferred":false,"id":389955,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kuivila, K.M.","contributorId":34529,"corporation":false,"usgs":true,"family":"Kuivila","given":"K.M.","email":"","affiliations":[],"preferred":false,"id":389957,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70021442,"text":"70021442 - 1999 - Estimation of long-term discharge statistics by regional adjustment","interactions":[],"lastModifiedDate":"2024-05-24T11:17:28.698495","indexId":"70021442","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","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":"Estimation of long-term discharge statistics by regional adjustment","docAbstract":"A regional adjustment relationship was developed to estimate long-term (30-year) monthly median discharges from short term (three-year) records. This method differs from traditional approaches in that it is based on site-specific discharge data but does not require correlation of these data with discharges from a single hydrologically similar long-term gage. The method is shown to be statistically robust, and applicable to statistics other than the median.A regional adjustment relationship was developed to estimate long-term (30-year) monthly discharges from short term (three-year) records. This method differs from traditional approaches in that it is based on site-specific discharge data but does not require correlation of these data with discharges from a single hydrologically similar long-term gage. The method is shown to be statistically robust, and applicable to statistics other than the median.","language":"English","publisher":"American Water Resources Association","doi":"10.1111/j.1752-1688.1999.tb04184.x","issn":"1093474X","usgsCitation":"Bakke, P., Thomas, R., and Parrett, C., 1999, Estimation of long-term discharge statistics by regional adjustment: Journal of the American Water Resources Association, v. 35, no. 4, p. 911-921, https://doi.org/10.1111/j.1752-1688.1999.tb04184.x.","productDescription":"11 p.","startPage":"911","endPage":"921","numberOfPages":"11","costCenters":[],"links":[{"id":229423,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"35","issue":"4","noUsgsAuthors":false,"publicationDate":"2007-06-08","publicationStatus":"PW","scienceBaseUri":"505a0b97e4b0c8380cd527b5","contributors":{"authors":[{"text":"Bakke, P.D.","contributorId":82083,"corporation":false,"usgs":true,"family":"Bakke","given":"P.D.","email":"","affiliations":[],"preferred":false,"id":389890,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Thomas, R.","contributorId":79205,"corporation":false,"usgs":true,"family":"Thomas","given":"R.","affiliations":[],"preferred":false,"id":389889,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Parrett, C.","contributorId":43400,"corporation":false,"usgs":true,"family":"Parrett","given":"C.","email":"","affiliations":[],"preferred":false,"id":389888,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70021439,"text":"70021439 - 1999 - A hydrometric and geochemical approach to test the transmissivity feedback hypothesis during snowmelt","interactions":[],"lastModifiedDate":"2012-03-12T17:19:38","indexId":"70021439","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2342,"text":"Journal of Hydrology","active":true,"publicationSubtype":{"id":10}},"title":"A hydrometric and geochemical approach to test the transmissivity feedback hypothesis during snowmelt","docAbstract":"To test the transmissivity feedback hypothesis of runoff generation, surface and subsurface waters were monitored and sampled during the 1996 snowmelt at various topographic positions in a 41 ha forested headwater catchment at Sleepers River, Vermont. Two conditions that promote transmissivity feedback existed in the catchment during the melt period. First, saturated hydraulic conductivity increased toward land surface, from a geometric mean of 3.6 mm h-1 in glacial till to 25.6 mm h-1 in deep soil to 54.0 mm h-1 in shallow soil. Second, groundwater levels rose to within 0.3 m of land surface at all riparian sites and most hillslope sites at peak melt. The importance of transmissivity feedback to streamflow generation was tested at the catchment scale by examination of physical and chemical patterns of groundwater in near-stream (discharge) and hillslope (recharge/lateral flow) zones, and within a geomorphic hollow (convergent flow). The presence of transmissivity feedback was supported by the abrupt increase in streamflow as the water table rose into the surficial, transmissive zone; a flattening of the groundwater level vs. streamflow curve occurred at most sites. This relation had a clockwise hysteresis (higher groundwater level for given discharge on rising limb than at same discharge on falling limb) at riparian sites, suggesting that the riparian zone was the dominant source area during the rising limb of the melt hydrograph. Hysteresis was counterclockwise at hillslope sites, suggesting that hillslope drainage controlled the snowmelt recession. End member mixing analysis using Ca, Mg, Na, dissolved organic carbon (DOC), and Si showed that stream chemistry could be explained as a two-component mixture of groundwater high in base cations and an O-horizon/overland flow water high in DOC. The dominance of shallow flow paths during events was indicated by the high positive correlation of DOC with streamflow (r2 = 0.82). Despite the occurrence of transmissivity feedback, hillslope till and soil water were ruled out as end members primarily because their distinctive high-Si composition had little or no effect on streamwater composition. Till water from the geomorphic hollow had a chemistry very close to streamwater base flow, and may represent the base flow end member better than the more concentrated riparian groundwater. During snowmelt, streamwater composition shifted as this base flow was diluted - not by shallow groundwater from the hillslope, but rather by a more surficial O-horizon/overland flow water.Surface and subsurface waters were analyzed to test the transmissivity feedback of runoff generation during the 1996 snowmelt in a catchment at Sleepers River, Vermont. The importance of transmissivity feedback to stream flow generation was tested by examination of physical and chemical patterns of groundwater in near-stream and hillslope zones within a geomorphic hollow. End member mixing analysis of Ca, Mg, Na, dissolved organic carbon (DOC), and Si showed that stream chemistry could be explained as a two-component mixture of groundwater high in base cations and an O-horizon/overland flow water high in DOC. The dominance of shallow water paths during the events was indicated by the high positive correlation of DOC with streamflow (r2 = 0.82).","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier Science B.V.","publisherLocation":"Amsterdam, Netherlands","doi":"10.1016/S0022-1694(99)00059-1","issn":"00221694","usgsCitation":"Kendall, K., Shanley, J.B., and McDonnell, J.J., 1999, A hydrometric and geochemical approach to test the transmissivity feedback hypothesis during snowmelt: Journal of Hydrology, v. 219, no. 3-4, p. 188-205, https://doi.org/10.1016/S0022-1694(99)00059-1.","startPage":"188","endPage":"205","numberOfPages":"18","costCenters":[],"links":[{"id":229347,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206303,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(99)00059-1"}],"volume":"219","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e42be4b0c8380cd4646c","contributors":{"authors":[{"text":"Kendall, K.A.","contributorId":94811,"corporation":false,"usgs":true,"family":"Kendall","given":"K.A.","email":"","affiliations":[],"preferred":false,"id":389875,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Shanley, J. B.","contributorId":52226,"corporation":false,"usgs":true,"family":"Shanley","given":"J.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":389873,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"McDonnell, Jeffery J. 0000-0002-3880-3162","orcid":"https://orcid.org/0000-0002-3880-3162","contributorId":62723,"corporation":false,"usgs":false,"family":"McDonnell","given":"Jeffery","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":389874,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70021429,"text":"70021429 - 1999 - Spectroscopic confirmation of uranium(VI)-carbonato adsorption complexes on hematite","interactions":[],"lastModifiedDate":"2018-12-19T08:47:34","indexId":"70021429","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","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":"Spectroscopic confirmation of uranium(VI)-carbonato adsorption complexes on hematite","docAbstract":"Evaluating societal risks posed by uranium contamination from waste management facilities, mining sites, and heavy industry requires knowledge about uranium transport in groundwater, often the most significant pathway of exposure to humans. It has been proposed that uranium mobility in aquifers may be controlled by adsorption of U(VI)−carbonato complexes on oxide minerals. The existence of such complexes has not been demonstrated, and little is known about their compositions and reaction stoichiometries. We have used attenuated total reflectance Fourier transform infrared (ATR-FTIR) and extended X-ray absorption fine structure (EXAFS) spectroscopies to probe the existence, structures, and compositions of ≡FeOsurface−U(VI)−carbonato complexes on hematite throughout the pH range of uranyl uptake under conditions relevant to aquifers. U(VI)−carbonato complexes were found to be the predominant adsorbed U(VI) species at all pH values examined, a much wider pH range than previously postulated based on analogy to aqueous U(VI)−carbonato complexes, which are trace constituents at pH < 6. This result indicates the inadequacy of the common modeling assumption that the compositions and predominance of adsorbed species can be inferred from aqueous species. By extension, adsorbed carbonato complexes may be of major importance to the groundwater transport of similar actinide contaminants such as neptunium and plutonium.","language":"English","publisher":"ACS","doi":"10.1021/es990048g","issn":"0013936X","usgsCitation":"Bargar, J.R., Reitmeyer, R., and Davis, J., 1999, Spectroscopic confirmation of uranium(VI)-carbonato adsorption complexes on hematite: Environmental Science & Technology, v. 33, no. 14, p. 2481-2484, https://doi.org/10.1021/es990048g.","productDescription":"4 p.","startPage":"2481","endPage":"2484","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":479512,"rank":10000,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://digital.library.unt.edu/ark:/67531/metadc624285/","text":"External Repository"},{"id":229754,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206436,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1021/es990048g"}],"volume":"33","issue":"14","noUsgsAuthors":false,"publicationDate":"1999-05-29","publicationStatus":"PW","scienceBaseUri":"505b95aee4b08c986b31b05f","contributors":{"authors":[{"text":"Bargar, John R.","contributorId":14970,"corporation":false,"usgs":true,"family":"Bargar","given":"John","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":389840,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Reitmeyer, Rebecca","contributorId":68917,"corporation":false,"usgs":true,"family":"Reitmeyer","given":"Rebecca","email":"","affiliations":[],"preferred":false,"id":389841,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Davis, James A.","contributorId":69289,"corporation":false,"usgs":true,"family":"Davis","given":"James A.","affiliations":[],"preferred":false,"id":389842,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70021411,"text":"70021411 - 1999 - The relative importance of light and nutrient limitation of phytoplankton growth: A simple index of coastal ecosystem sensitivity to nutrient enrichment","interactions":[],"lastModifiedDate":"2018-12-19T08:40:31","indexId":"70021411","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":863,"text":"Aquatic Ecology","active":true,"publicationSubtype":{"id":10}},"title":"The relative importance of light and nutrient limitation of phytoplankton growth: A simple index of coastal ecosystem sensitivity to nutrient enrichment","docAbstract":"Anthropogenic nutrient enrichment of the coastal zone is now a well-established fact. However, there is still uncertainty about the mechanisms through which nutrient enrichment can disrupt biological communities and ecosystem processes in the coastal zone. For example, while some estuaries exhibit classic symptoms of acute eutrophication, including enhanced production of algal biomass, other nutrient-rich estuaries maintain low algal biomass and primary production. This implies that large differences exist among coastal ecosystems in the rates and patterns of nutrient assimilation and cycling. Part of this variability comes from differences among ecosystems in the other resource that can limit algal growth and production - the light energy required for photosynthesis. Complete understanding of the eutrophication process requires consideration of the interacting effects of light and nutrients, including the role of light availability as a regulator of the expression of eutrophication. A simple index of the relative strength of light and nutrient limitation of algal growth can be derived from models that describe growth rate as a function of these resources. This index can then be used as one diagnostic to classify the sensitivity of coastal ecosystems to the harmful effects of eutrophication. Here I illustrate the application of this diagnostic with light and nutrient measurements made in three California estuaries and two Dutch estuaries.
","language":"English","publisher":"Kluwer Academic Publishers","doi":"10.1023/A:1009952125558","issn":"13862588","usgsCitation":"Cloern, J., 1999, The relative importance of light and nutrient limitation of phytoplankton growth: A simple index of coastal ecosystem sensitivity to nutrient enrichment: Aquatic Ecology, v. 33, no. 1, p. 3-16, https://doi.org/10.1023/A:1009952125558.","productDescription":"14 p. ","startPage":"3","endPage":"16","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"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":230074,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206514,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1023/A:1009952125558"}],"volume":"33","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505baf2ce4b08c986b3245da","contributors":{"authors":[{"text":"Cloern, J. E.","contributorId":59453,"corporation":false,"usgs":true,"family":"Cloern","given":"J. E.","affiliations":[],"preferred":false,"id":389785,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70021403,"text":"70021403 - 1999 - Cu(II) binding by a pH-fractionated fulvic acid","interactions":[],"lastModifiedDate":"2020-01-04T14:52:40","indexId":"70021403","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":760,"text":"Analytica Chimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"Cu(II) binding by a pH-fractionated fulvic acid","docAbstract":"The relationship between acidity, Cu(II) binding and sorption to XAD resin was examined using Suwannee River fulvic acid (SRFA). The work was based on the hypothesis that fractions of SRFA eluted from an XAD column at various pH's from 1.0 to 12.0 would show systematic variations in acidity and possibly aromaticity which in turn would lead to different Cu(II) binding properties. We measured equilibrium Cu(II) binding to these fractions using Cu2+ ion-selective electrode (ISE) potentiometry at pH 6.0. Several model ligands were also examined, including cyclopentane-1,2,3,4-tetracarboxylic acid (CP-TCA) and tetrahydrofuran-2,3,4,5-tetracarboxylic acid (THF-TCA), the latter binding Cu(II) much more strongly as a consequence of the ether linkage. The SRFA Cu(II) binding properties agreed with previous work at high ionic strength, and binding was enhanced substantially at lower ionic strength, in agreement with Poisson-Boltzmann predictions for small spheres. Determining Cu binding constants (K(i)) by non-linear regression with total ligand concentrations (L(Ti)) taken from previous work, the fractions eluted at varying pH had K(i) similar to the unfractionated SRFA, with a maximum enhancement of 0.50 log units. We conclude that variable-pH elution from XAD does not isolate significantly strong (or weak) Cu(II)-binding components from the SRFA mixture.
","language":"English","publisher":"Elsevier","doi":"10.1016/S0003-2670(99)00521-8","issn":"00032670","usgsCitation":"Brown, G., Cabaniss, S., MacCarthy, P., and Leenheer, J., 1999, Cu(II) binding by a pH-fractionated fulvic acid: Analytica Chimica Acta, v. 402, no. 1-2, p. 183-193, https://doi.org/10.1016/S0003-2670(99)00521-8.","productDescription":"11 p.","startPage":"183","endPage":"193","numberOfPages":"11","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":229952,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"402","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059fd03e4b0c8380cd4e5b1","contributors":{"authors":[{"text":"Brown, G.K.","contributorId":62362,"corporation":false,"usgs":true,"family":"Brown","given":"G.K.","email":"","affiliations":[],"preferred":false,"id":389747,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cabaniss, S.E.","contributorId":76487,"corporation":false,"usgs":true,"family":"Cabaniss","given":"S.E.","email":"","affiliations":[],"preferred":false,"id":389749,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"MacCarthy, P.","contributorId":88081,"corporation":false,"usgs":true,"family":"MacCarthy","given":"P.","email":"","affiliations":[],"preferred":false,"id":389750,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Leenheer, J.A.","contributorId":75123,"corporation":false,"usgs":true,"family":"Leenheer","given":"J.A.","affiliations":[],"preferred":false,"id":389748,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70021402,"text":"70021402 - 1999 - Simultaneous determination of Ca, Cu, Ni, Zn and Cd binding strengths with fulvic acid fractions by Schubert's method","interactions":[],"lastModifiedDate":"2018-12-19T08:18:02","indexId":"70021402","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":760,"text":"Analytica Chimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"Simultaneous determination of Ca, Cu, Ni, Zn and Cd binding strengths with fulvic acid fractions by Schubert's method","docAbstract":"The equilibrium binding of Ca2+, Ni2+, Cd2+, Cu2+ and Zn2+ with unfractionated Suwannee river fulvic acid (SRFA) and an enhanced metal binding subfraction of SRFA was measured using Schubert’s ion-exchange method at pH 6.0 and at an ionic strength (μ) of 0.1 (NaNO3). The fractionation and subfractionation were directed towards obtaining an isolate with an elevated metal binding capacity or binding strength as estimated by Cu2+ potentiometry (ISE). Fractions were obtained by stepwise eluting an XAD-8 column loaded with SRFA with water eluents of pH 1.0 to pH 12.0. Subfractions were obtained by loading the fraction eluted from XAD-8 at pH 5.0 onto a silica gel column and eluting with solvents of increasing polarity. Schuberts ion exchange method was rigorously tested by measuring simultaneously the conditional stability constants (K) of citric acid complexed with the five metals at pH 3.5 and 6.0. The log K of SRFA with Ca2+, Ni2+, Cd2+, Cu2+ and Zn2+ determined simultaneously at pH 6.0 follow the sequence of Cu2+ > Cd2+ > Ni2+ > Zn2+ > Ca2+ while all log K values increased for the enhanced metal binding subfraction and followed a different sequence of Cu2+ > Cd2+ > Ca2+ > Ni2+ > Zn2+. Both fulvic acid samples and citric acid exhibited a 1 : 1 metal to ligand stochiometry under the relatively low metal loading conditions used here. Quantitative
The transformation of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] and alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide] in aquatic systems was investigated using outdoor tank mesocosms. Metolachlor and alachlor levels and their ethane sulfonic acid (ESA) and oxanillic acid breakdown products were monitored over time under five experimental treatments (each in quadruplicate). Background water conditions were identical in all treatments with each treatment differing based on the level and type(s) of herbicide present. Treatments included a no-herbicide control, 10 μg/L metolachlor, 25 μg/L metolachlor, 25 μg/L alachlor, and 25 μg/L alachlor plus 25 μg/L metolachlor in combination. The experiment was initiated by adding herbicide(s) to the units to the target concentrations; herbicide and breakdown product levels and other chemical parameters were then monitored for 85 days. In general, metolachlor half-lives were longer than alachlor half-lives under all treatments, although the differences were not statistically significant. Metolachlor half-lives (±95% confidence limits) ranged from 33.0 d (±14.1 d) to 46.2 d (±40.0 d), whereas alachlor half-lives ranged from 18.7 d (±3.5 d) to 21.0 d (±6.5 d) for different treatments. Formation patterns of ESA were similar in all treatments, whereas oxanillic acid formation differed for the two herbicides. Alachlor oxanillic acid was produced in larger quantities than metolachlor oxanillic acid and either ESA under equivalent conditions. Our results suggest that the transformation pathways for alachlor and metolachlor in aquatic systems are similar and resemble the acetochlor pathway in soils proposed by Feng (Pestic. Biochem. Physiol. 1991, 34, 136); however, the oxanillic acid branch of the pathway is favored for alachlor as compared with metolachlor.
Bacteriophage PRD1 and silica colloids were co-injected into sewage-contaminated and uncontaminated zones of an iron oxide-coated sand aquifer on Cape Cod, MA, and their transport was monitored over distances up to 6 m in three arrays. After deposition, the attached PRD1 and silica colloids were mobilized by three different chemical perturbations (elevated pH, anionic surfactant, and reductant). PRD1 and silica colloids experienced less attenuation in the contaminated zone where adsorbed organic matter and phosphate may be hindering attachment of PRD1 and silica colloids to the iron oxide coatings. The PRD1 collision efficiencies agree well with collision efficiencies predicted by assuming favorable PRD1 deposition on iron oxide coatings for which the surface area coverage was measured by microprobe analysis of sediment thin sections. ζ potentials of the PRD1, silica colloids, and aquifer grains corroborated the transport results, indicating that electrostatic forces dominated the attachment of PRD1 and silica colloids. Elevated pH was the chemical perturbation most effective at mobilizing the attached PRD1 and silica colloids. Elevated surfactant concentration mobilized the attached PRD1 and silica colloids more effectively in the contaminated zone than in the uncontaminated zone.
","language":"English","publisher":"ACS","doi":"10.1021/es980350+","issn":"0013936X","usgsCitation":"Ryan, J.N., Elimelech, M., Ard, R., Harvey, R., and Johnson, P., 1999, Bacteriophage PRD1 and silica colloid transport and recovery in an iron oxide-coated sand aquifer: Environmental Science & Technology, v. 33, no. 1, p. 63-73, https://doi.org/10.1021/es980350+.","productDescription":"11 p.","startPage":"63","endPage":"73","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":230521,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"33","issue":"1","noUsgsAuthors":false,"publicationDate":"1998-11-19","publicationStatus":"PW","scienceBaseUri":"5059efa7e4b0c8380cd4a395","contributors":{"authors":[{"text":"Ryan, J. N.","contributorId":102649,"corporation":false,"usgs":true,"family":"Ryan","given":"J.","email":"","middleInitial":"N.","affiliations":[],"preferred":false,"id":392580,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Elimelech, M.","contributorId":105469,"corporation":false,"usgs":true,"family":"Elimelech","given":"M.","affiliations":[],"preferred":false,"id":392581,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Ard, R.A.","contributorId":13005,"corporation":false,"usgs":true,"family":"Ard","given":"R.A.","email":"","affiliations":[],"preferred":false,"id":392578,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Harvey, R.W. 0000-0002-2791-8503","orcid":"https://orcid.org/0000-0002-2791-8503","contributorId":11757,"corporation":false,"usgs":true,"family":"Harvey","given":"R.W.","affiliations":[],"preferred":false,"id":392577,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Johnson, P.R.","contributorId":37332,"corporation":false,"usgs":true,"family":"Johnson","given":"P.R.","email":"","affiliations":[],"preferred":false,"id":392579,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70021325,"text":"70021325 - 1999 - The effect of frozen soil on snowmelt runoff at Sleepers River, Vermont","interactions":[],"lastModifiedDate":"2024-03-25T23:16:29.10803","indexId":"70021325","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"The effect of frozen soil on snowmelt runoff at Sleepers River, Vermont","docAbstract":"Soil frost depth has been monitored at the Sleepers River Research Watershed in northeastern Vermont since 1984. Soil frost develops every winter, particularly in open fields, but its depth varies greatly from year to year in inverse relation to snow depth. During the 15 years of record at a benchmark mid-elevation open site, the annual maximum frost depth varied from 70 to 390 mm. We empirically tested the hypothesis that frozen soil prevents infiltration and recharge, thereby causing an increased runoff ratio (streamflow/(rain+snowmelt)) during the snowmelt hydrograph rise and a decreased runoff ratio during snowmelt recession. The hypothesis was not supported at the 111 km2 W-5 catchment; there was no significant correlation of the runoff ratio with the seasonal maximum frost depth for either the pre-peak or post-peak period. In an analysis of four events, however, the presence of frost promoted a large and somewhat quicker response to rainfall relative to the no-frost condition, although snow cover caused a much greater time-to-peak regardless of frost status. For six years of flow and frost depth measured at the 59 ha agricultural basin W-2, the hypothesis appeared to be supported. The enhancement of runoff due to soil frost is evident on small plots and in extreme events, such as rain on frozen snow-free soil. In the northeastern USA and eastern Canada, the effect is often masked in larger catchments by several confounding factors, including storage of meltwater in the snowpack, variability in snowmelt timing due to elevational and aspect differences, interspersed forested land where frost may be absent, and the timing of soil thawing relative to the runoff peak.
A study site underlain by a claypan soil was instrumented to examine the transport of fertilizer nitrogen (N) under corn (Zea mays L.) cultivation. The study was designed to examine N transport within the unsaturated zone and in intedlow (the saturated flow of water on top of the claypan). A 15N-labeled fertilizer (labeled N), bromide (Br), and chloride (Cl) were used as field tracers. Rapid or prolonged infiltration events allowed water and dissolved solutes to perch on the claypan for brief periods. However, a well-developed network of preferential flow paths quickly diverted water and solutes through the claypan and into the underlying glacial till aquifer. Excess fertilizer N in the unsaturated zone supplied a continuous, but declining input of N to ground water for a period of 15 mo after a single fertilizer application. Calculated solute velocities through the claypan matrix (6.4 × 10−6 cm s−1) were similar to horizontal transport rates along the claypan (3.5 to 7.3 × 10−6 cm s−1) but much slower than infiltration rates determined for preferential flow paths (1.67 × 10−3 cm s−1). These flow paths accounted for 35% of the transport. A seasonally variable, dual mode of transport (matrix and preferential flow) prevented the daypan from being an effective barrier to vertical transport. Simulations of selected field observations, conducted using the variably saturated two-dimensional flow and transport model, VS2DT, confirmed the presence of a dual flow regime in the claypan.
Enzymatic and histopathologic alterations of the digestive gland, gill, gonad, and kidney were studied in Asian clam (Potamocorbula amurensis) in April, 1997 from each of four United States Geological Survey (USGS) stations in the San Francisco Estuary. Stations were selected based on differing body burdens of metallic contaminants in clams (Stn 4.1>6.1>8.1>12.5) observed over 7 years. Because no pristine sites are known within the estuary and because no laboratory-reared stocks of P. amurensis were available, clams from station 12.5 served as reference animals. Histopathologic analysis revealed no lesions in clams collected from station 12.5. Mild digestive gland atrophy and moderate distal kidney tubular vacuolation were seen in clams collected from station 8.1. Mild digestive gland atrophy, moderate kidney tubular atrophy, and moderate gill inflammation were seen in clams collected from station 6.1. Lesions found only in clams from station 4.1 were: (1) severe inflammation and moderate atrophy of primary ducts and diverticula, and decreased numbers of heterophagosomes and heterolysosomes in diverticula of the digestive gland; (2) severe gill inflammation; (3) severe kidney tubular atrophy; (4) severe ovarian and testicular inflammation and necrosis (5) decreased numbers of mature ova; and (6) decreased number of glycogen storage cells in the ovary and testis. Localization of specific enzymes including adenosine triphosphatase (ATP), acid phosphatase (ACP), alkaline phosphatase (ALKP), gamma-glutamyl transpeptidase (GGT), and glucose-6-phosphate dehydrogenase (G6PDH) was performed and correlated, in serial sections with glycogen (PAS) and haematoxylin and eosin stains. Enzymatic analysis revealed: (1) increased digestive diverticula ATP in stations 6.1 and 4.1; (2) decreased digestive diverticula ACP in stations 6.1 and 4.1 and proximal kidney tubular ACP deficiency in station 4.1; (3) no ALKP differences among stations; (4) increased distal kidney tubular GGT at station 12.5 and decreased distal kidney tubular GGT at station 4.1; (5) decreased digestive diverticula G6PDH G6PDH in all stations except 12.5 and decreased proximal kidney tubular G6PDH in stations 8.1 and 6.1. It is possible that other anthropogenic and natural stressors may have affected the results in this study. However, the prevalence and increased severity of lesions in clams with highest metal body burden suggests a contaminant- associated etiology. Enzymatic and histopathologic biomarker alterations identified in this study were positively correlated with the metal body burden. Clams with the higher prevalence of diseases and enzyme alterations also showed a lower condition index and glycogen content in the month when histopathological assessment was performed. Further study will seek to develop enzymatic and histopathologic biomarkers for use in controlled laboratory conditions to help validate the field study.
","language":"English","publisher":"Taylor and Francis","doi":"10.1080/135475099230660","usgsCitation":"Teh, S., Clark, S., Brown, C.L., Luoma, S., and Hinton, D., 1999, Enzymatic and histopathologic biomarkers as indicators of contaminant exposure and effect in Asian clam (Potamocorbula amurensis): Biomarkers, v. 4, no. 6, p. 497-509, https://doi.org/10.1080/135475099230660.","productDescription":"13 p.","startPage":"497","endPage":"509","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"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":229946,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"4","issue":"6","noUsgsAuthors":false,"publicationDate":"2008-09-29","publicationStatus":"PW","scienceBaseUri":"505a09f0e4b0c8380cd52110","contributors":{"authors":[{"text":"Teh, S.J.","contributorId":29596,"corporation":false,"usgs":true,"family":"Teh","given":"S.J.","email":"","affiliations":[],"preferred":false,"id":389345,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Clark, S.L.","contributorId":88113,"corporation":false,"usgs":true,"family":"Clark","given":"S.L.","email":"","affiliations":[],"preferred":false,"id":389349,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Brown, C. L.","contributorId":35678,"corporation":false,"usgs":true,"family":"Brown","given":"C.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":389346,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Luoma, S. N.","contributorId":86353,"corporation":false,"usgs":true,"family":"Luoma","given":"S. N.","affiliations":[],"preferred":false,"id":389348,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Hinton, D.E.","contributorId":75489,"corporation":false,"usgs":true,"family":"Hinton","given":"D.E.","email":"","affiliations":[],"preferred":false,"id":389347,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70021284,"text":"70021284 - 1999 - Seasonal change in precipitation, snowpack, snowmelt, soil water and streamwater chemistry, northern Michigan","interactions":[],"lastModifiedDate":"2024-03-25T23:24:14.206984","indexId":"70021284","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"Seasonal change in precipitation, snowpack, snowmelt, soil water and streamwater chemistry, northern Michigan","docAbstract":"No abstract available.
","language":"English","publisher":"Wiley","doi":"10.1002/(SICI)1099-1085(199910)13:14/15<2215::AID-HYP882>3.0.CO;2-V","issn":"08856087","usgsCitation":"Stottlemyer, R., and Toczydlowski, D., 1999, Seasonal change in precipitation, snowpack, snowmelt, soil water and streamwater chemistry, northern Michigan: Hydrological Processes, v. 13, no. 14-15, p. 2215-2231, https://doi.org/10.1002/(SICI)1099-1085(199910)13:14/15<2215::AID-HYP882>3.0.CO;2-V.","productDescription":"17 p.","startPage":"2215","endPage":"2231","numberOfPages":"17","costCenters":[],"links":[{"id":229906,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"13","issue":"14-15","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b887fe4b08c986b3169d1","contributors":{"authors":[{"text":"Stottlemyer, R.","contributorId":44493,"corporation":false,"usgs":true,"family":"Stottlemyer","given":"R.","email":"","affiliations":[],"preferred":false,"id":389344,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Toczydlowski, D.","contributorId":9790,"corporation":false,"usgs":true,"family":"Toczydlowski","given":"D.","email":"","affiliations":[],"preferred":false,"id":389343,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70021280,"text":"70021280 - 1999 - Transformations of snow chemistry in the boreal forest: Accumulation and volatilization","interactions":[],"lastModifiedDate":"2024-03-25T23:26:41.034256","indexId":"70021280","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"Transformations of snow chemistry in the boreal forest: Accumulation and volatilization","docAbstract":"This paper examines the processes and dynamics of ecologically-important inorganic chemical (primarily NO3-N) accumulation and loss in boreal forest snow during the cold winter period at a northern and southern location in the boreal forest of western Canada. Field observations from Inuvik, Northwest Territories and Waskesiu, Saskatchewan, Canada were used to link chemical transformations and physical processes in boreal forest snow. Data on the disposition and overwinter transformation of snow water equivalent, NO3-, SO42- and other major ions were examined. No evidence of enhanced dry deposition of chemical species to intercepted snow was found at either site except where high atmospheric aerosol concentrations prevailed. At Inuvik, concentrations of SO42- and Cl- were five to six times higher in intercepted snow than in surface snow away from the trees. SO4-S and Cl loads at Inuvik were correspondingly enhanced three-fold within the nearest 0.5 m to individual tree stems. Measurements of snow affected by canopy interception without rapid sublimation provided no evidence of ion volatilization from intercepted snow. Where intercepted snow sublimation rates were significant, ion loads in sub-canopy snow suggested that NO3- volatized with an efficiency of about 62% per snow mass sublimated. Extrapolating this measurement from Waskesiu to sublimation losses observed in other southern boreal environments suggests that 19-25% of snow inputs of NO3- can be lost during intercepted snow sublimation. The amount of N lost during sublimation may be large in high-snowfall, high N load southern boreal forests (Quebec) where 0.42 kg NO3-N ha-1 is estimated as a possible seasonal NO3- volatilization. The sensitivity of the N fluxes to climate and forest canopy variation and implications of the winter N losses for N budgets in the boreal forest are discussed.This paper examines the processes and dynamics of ecologically-important inorganic chemical (primarily NO3-N) accumulation and loss in boreal forest snow during the cold winter period at a northern and southern location in the boreal forest of western Canada. Field observations from Inuvik. Northwest Territories and Waskesiu, Saskatchewan, Canada were used to link chemical transformations and physical processes in boreal forest snow. Data on the disposition and overwinter transformation of snow water equivalent, NO3-, SO42- and other major ions were examined. No evidence of enhanced dry deposition of chemical species to intercepted snow was found at either site except where high atmospheric aerosol concentrations prevailed. At Inuvik, concentrations of SO42- and Cl- were five to six times higher in intercepted snow than in surface snow away from the trees. SO4-S and Cl loads at Inuvik were correspondingly enhanced three-fold within the nearest 0.5 m to individual tree stems. Measurements of snow affected by canopy interception without rapid sublimation provided no evidence of ion volatilization from intercepted snow. Where intercepted snow sublimation rates were significant, ion loads in sub-canopy snow suggested that NO3- volatized with an efficiency of about 62% per snow mass sublimated. Extrapolating this measurement from Waskesiu to sublimation losses observed in other southern boreal environments suggests that 19-25% of snow inputs of NO3- can be lost during intercepted snow sublimation. The amount of N lost during sublimation may be large in high-snowfall, high N load southern boreal forests (Quebec) where 0.42 kg NO3-N ha-1 is estimated as a possible seasonal NO3- volatilization. The sensitivity of the N fluxes to climate and forest canopy variation and implications of the winter N losses for N budgets in the boreal forest are discussed.","language":"English","publisher":"Wiley","doi":"10.1002/(SICI)1099-1085(199910)13:14/15<2257::AID-HYP874>3.0.CO;2-G","issn":"08856087","usgsCitation":"Pomeroy, J., Davies, T., Jones, H., Marsh, P., Peters, N., and Tranter, M., 1999, Transformations of snow chemistry in the boreal forest: Accumulation and volatilization: Hydrological Processes, v. 13, no. 14-15, p. 2257-2273, https://doi.org/10.1002/(SICI)1099-1085(199910)13:14/15<2257::AID-HYP874>3.0.CO;2-G.","productDescription":"17 p.","startPage":"2257","endPage":"2273","numberOfPages":"17","costCenters":[],"links":[{"id":229862,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"13","issue":"14-15","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb6f3e4b08c986b326f6c","contributors":{"authors":[{"text":"Pomeroy, J.W.","contributorId":49223,"corporation":false,"usgs":true,"family":"Pomeroy","given":"J.W.","email":"","affiliations":[],"preferred":false,"id":389322,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Davies, T.D.","contributorId":86513,"corporation":false,"usgs":true,"family":"Davies","given":"T.D.","email":"","affiliations":[],"preferred":false,"id":389323,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Jones, H.G.","contributorId":106757,"corporation":false,"usgs":true,"family":"Jones","given":"H.G.","email":"","affiliations":[],"preferred":false,"id":389325,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Marsh, P.","contributorId":99279,"corporation":false,"usgs":true,"family":"Marsh","given":"P.","affiliations":[],"preferred":false,"id":389324,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Peters, N.E.","contributorId":33332,"corporation":false,"usgs":true,"family":"Peters","given":"N.E.","email":"","affiliations":[],"preferred":false,"id":389321,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Tranter, M.","contributorId":22525,"corporation":false,"usgs":true,"family":"Tranter","given":"M.","email":"","affiliations":[],"preferred":false,"id":389320,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70021276,"text":"70021276 - 1999 - Occurrence and transport of acetochlor in streams of the Mississippi River Basin","interactions":[],"lastModifiedDate":"2018-12-19T08:23:54","indexId":"70021276","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2262,"text":"Journal of Environmental Quality","active":true,"publicationSubtype":{"id":10}},"title":"Occurrence and transport of acetochlor in streams of the Mississippi River Basin","docAbstract":"The herbicide acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl) acetamide] was first used on corn (Zea mays L.) in the USA during the growing season of 1994. By 1996, it was the third most heavily used corn herbicide in the midwestern USA. During the growing season of 1997, 78% of 375 samples collected at 32 stream sites in the Mississippi River Basin contained detectable concentrations of acetochlor. However, concentrations in only 2% of the samples exceeded 2/µg/L, the maximum annual average concentration allowable in public water supplies derived primarily from surface water. The largest acetochlor concentrations were detected in streams draining basins in parts of Illinois, Indiana, and Iowa. The median concentration of acetochlor in streams was about 10% that of atrazine (6-chloro-N-ethyl-N-isopropyl-1,3,5-triazine-2,4-diamine), about 25% that of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide], about 50% that of cyanazine [2-[[4-chloro-6-(ethylamino)-l,3,5-triazin-2-yl]amino]-2-methylpropionitrile], and about threefold that of alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide]. Load estimates indicate that, during the growing season of 1997, agricultural subbasins draining areas of Illinois, Indiana, and Iowa contributed about 37 000 kg, or 74%, of the 50 000 kg of acetochlor measured in streams of the Mississippi River Basin.
","language":"English","publisher":"ACSESS","doi":"10.2134/jeq1999.00472425002800060014x","issn":"00472425","usgsCitation":"Clark, G.M., and Goolsby, D.A., 1999, Occurrence and transport of acetochlor in streams of the Mississippi River Basin: Journal of Environmental Quality, v. 28, no. 6, p. 1787-1795, https://doi.org/10.2134/jeq1999.00472425002800060014x.","productDescription":"9 p.","startPage":"1787","endPage":"1795","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":229783,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"28","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6b81e4b0c8380cd74731","contributors":{"authors":[{"text":"Clark, G. M.","contributorId":90325,"corporation":false,"usgs":true,"family":"Clark","given":"G.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":389310,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Goolsby, D. A.","contributorId":50508,"corporation":false,"usgs":true,"family":"Goolsby","given":"D.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":389309,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70021261,"text":"70021261 - 1999 - Characterizing a sewage plume using the 3H-3He dating technique","interactions":[],"lastModifiedDate":"2018-12-21T06:17:11","indexId":"70021261","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","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":"Characterizing a sewage plume using the 3H-3He dating technique","docAbstract":"An extensive 3H-3He study was performed to determine detailed characteristics of a regional flow system and a sewage plume over a distance of 4 km in a sand and gravel aquifer at Otis Air Base in Falmouth, Massachusetts. 3H-3He ages increase with depth in individual piezometer clusters and with distance along flowpaths. However, the age gradient with depth (Δt/Δz) is smaller in the plume than that in the regional waters, due to the intense recharge in the infiltration beds. The 1960s bomb peak of tritium in precipitation is archived longitudinally along a flowline through the main axis of the plume and vertically in individual piezometer clusters. On the eastern side of the sampling area, where water from Ashumet Pond forces plume water deeper into the flow system, 3H-3He ages are young at depth because the 3H-3He \"clock\" is reset due to outgassing of helium in the pond. A reconstruction of the tritium input functions for the regional and plume samples shows that there is no offset in the peak [3H]+[3Hetrit] concentrations for the plume and regional water, indicating that the water from supply wells for use on the base is young. The 3H-3He ages and detergent concentrations in individual wells are consistent with the beginning of use of detergents and the time period when their concentrations in sewage would have been greatest. Ages and hydraulic properties calculated using the 3H-3He data compare well with those from previous investigations and from particle-tracking simulations.","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.1999.tb01185.x","issn":"0017467X","usgsCitation":"Shapiro, S.D., LeBlanc, D., Schlosser, P., and Ludin, A., 1999, Characterizing a sewage plume using the 3H-3He dating technique: Ground Water, v. 37, no. 6, p. 861-878, https://doi.org/10.1111/j.1745-6584.1999.tb01185.x.","productDescription":"18 p.","startPage":"861","endPage":"878","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":230142,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":278552,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1111/j.1745-6584.1999.tb01185.x"}],"volume":"37","issue":"6","noUsgsAuthors":false,"publicationDate":"2005-08-04","publicationStatus":"PW","scienceBaseUri":"5059f4ede4b0c8380cd4bfeb","contributors":{"authors":[{"text":"Shapiro, Stephanie Dunkle","contributorId":82738,"corporation":false,"usgs":true,"family":"Shapiro","given":"Stephanie","email":"","middleInitial":"Dunkle","affiliations":[],"preferred":false,"id":389254,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"LeBlanc, Denis","contributorId":11363,"corporation":false,"usgs":true,"family":"LeBlanc","given":"Denis","affiliations":[],"preferred":false,"id":389252,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Schlosser, Peter","contributorId":50936,"corporation":false,"usgs":true,"family":"Schlosser","given":"Peter","email":"","affiliations":[],"preferred":false,"id":389253,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ludin, Andrea","contributorId":93232,"corporation":false,"usgs":true,"family":"Ludin","given":"Andrea","email":"","affiliations":[],"preferred":false,"id":389255,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70021244,"text":"70021244 - 1999 - Bacterial respiration of arsenic and selenium","interactions":[],"lastModifiedDate":"2018-12-19T08:42:05","indexId":"70021244","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1621,"text":"FEMS Microbiology Reviews","active":true,"publicationSubtype":{"id":10}},"title":"Bacterial respiration of arsenic and selenium","docAbstract":"Oxyanions of arsenic and selenium can be used in microbial anaerobic respiration as terminal electron acceptors. The detection of arsenate and selenate respiring bacteria in numerous pristine and contaminated environments and their rapid appearance in enrichment culture suggest that they are widespread and metabolically active in nature. Although the bacterial species that have been isolated and characterized are still few in number, they are scattered throughout the bacterial domain and include Gram- positive bacteria, beta, gamma and epsilon Proteobacteria and the sole member of a deeply branching lineage of the bacteria, Chrysiogenes arsenatus. The oxidation of a number of organic substrates (i.e. acetate, lactate, pyruvate, glycerol, ethanol) or hydrogen can be coupled to the reduction of arsenate and selenate, but the actual donor used varies from species to species. Both periplasmic and membrane-associated arsenate and selenate reductases have been characterized. Although the number of subunits and molecular masses differs, they all contain molybdenum. The extent of the environmental impact on the transformation and mobilization of arsenic and selenium by microbial dissimilatory processes is only now being fully appreciated.","language":"English","publisher":"FEMS","doi":"10.1016/S0168-6445(99)00024-8","issn":"01686445","usgsCitation":"Stolz, J., and Oremland, R., 1999, Bacterial respiration of arsenic and selenium: FEMS Microbiology Reviews, v. 23, no. 5, p. 615-627, https://doi.org/10.1016/S0168-6445(99)00024-8.","productDescription":"13 p.","startPage":"615","endPage":"627","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":487419,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1016/s0168-6445(99)00024-8","text":"Publisher Index Page"},{"id":229821,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206458,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0168-6445(99)00024-8"}],"volume":"23","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059efa4e4b0c8380cd4a385","contributors":{"authors":[{"text":"Stolz, J.F.","contributorId":94022,"corporation":false,"usgs":true,"family":"Stolz","given":"J.F.","email":"","affiliations":[],"preferred":false,"id":389186,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Oremland, R.S.","contributorId":97512,"corporation":false,"usgs":true,"family":"Oremland","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":389187,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ]}