Richard L. Smith, Ph.D.

Science and Products

• Science
  Label

  link

  

  February 23, 2017

  Nitrate Addition Enhances Arsenic Immobilization in Groundwater

  The addition of nitrate in a low oxygen groundwater resulted in the immobilization of naturally occurring dissolved arsenic and the conversion of nitrate to innocuous nitrogen gas.

  By

  Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology

  link

  February 23, 2017

  Nitrate Addition Enhances Arsenic Immobilization in Groundwater

  The addition of nitrate in a low oxygen groundwater resulted in the immobilization of naturally occurring dissolved arsenic and the conversion of nitrate to innocuous nitrogen gas.

  Learn More

  link

  

  June 21, 2016

  USGS Scientists Measure New Bacterial Nitrogen Removal Process in Groundwater

  For the first time, U.S. Geological Survey (USGS), Virginia Institute of Marine Science, and the University of Connecticut scientists have detected active anammox bacteria in groundwater.

  By

  Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology

  link

  June 21, 2016

  USGS Scientists Measure New Bacterial Nitrogen Removal Process in Groundwater

  For the first time, U.S. Geological Survey (USGS), Virginia Institute of Marine Science, and the University of Connecticut scientists have detected active anammox bacteria in groundwater.

  Learn More
• Data
  Label

  July 2, 2021

  Chemical Data From 40 Years of Monitoring a Treated-Wastewater Groundwater Plume in a Sand and Gravel Aquifer, Cape Cod, Massachusetts, 1978-2018

  This U.S. Geological Survey data release provides a comprehensive dataset of water-quality data and sampling-site characteristics collected in 1978-2018 during a study of the effects of land disposal of treated wastewater on groundwater quality in an unconsolidated sand and gravel aquifer on Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to rapid-infiltration beds at Joi

  By

  New England Water Science Center

  June 14, 2021

  Microbial Community and N-cycling gene abundance from Ponds and Groundwater on Cape Cod, MA (2015 - 2018)

  Surface water, pore water, pond bottom sediments, and groundwater were sampled within and downgradient from five groundwater flow-through ponds that ranged from oligotrophic to eutrophic in Cape Cod, Massachusetts during different seasons from 2015 – 2018. The sampled ponds included Ashumet, Santuit, Snake, Shubael, and Longs. Pore water was collected between 15 to 100 cm below the pond bottoms on

  By

  Water Resources Mission Area

  December 1, 2020

  Surface Water and Porewater Chemistry of Cell 3A, Prado Wetlands, Riverside, CA, USA (2018)

  The data presented here was collected at Prado Wetlands in Riverside County, CA, USA. Physical water column parameters were collected using a multprobe sonde and includes date and time of sample collection, location (inlet, outlet), temperature (degrees Celsius), pH, specific conductivity (mircoSiemens per centimeter), and dissolved oxygen (milligrams per liter). An ISCO autosampler was utilized t

  By

  Water Resources Mission Area

  June 5, 2020

  Nitrogen biogeochemistry in a boreal headwater stream network in Interior Alaska, 2008 to 2011

  High latitude, boreal watersheds are nitrogen-limited ecosystems that export large amounts of organic carbon. Key controls on carbon cycling in these environments are the biogeochemical processes affecting the nitrogen cycle. This data release presents results of a 3-year field study from 2008-2011 to document the relation between seasonal and transport-associated changes in carbon and nitrogen

  By

  Water Resources Mission Area

  June 27, 2019

  Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed

  The U.S. Geological Survey Toxic Substances Hydrology Program at Cape Cod has been investigating the fate and transport of a treated-wastewater, groundwater contaminant plume. A portion of the contaminated groundwater discharges into Ashumet Pond, a kettle hole, freshwater lake. A study was conducted from June 2013 to June 2015 to document transport, transformation, and discharge of dissolved inor

  By

  Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology

  January 30, 2019

  Natural gradient, lakebed tracer tests using nitrite in a nitrate-contaminated groundwater discharge zone in Ashumet Pond, Massachusetts

  The U.S. Geological Survey Toxic Substances Hydrology Program at Cape Cod has been investigating the fate and transport of a treated-wastewater, groundwater contaminant plume. A portion of the contaminated groundwater discharges into Ashumet Pond, a kettle hole, freshwater lake. A study was conducted from June 2013 to June 2015 to document transport, transformation, and discharge of dissolved inor

  By

  Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology
• Multimedia
  Label

  

  link
• Publications
  Filter Total Items: 37

  Publication Type (field_pub_type)

  TypeArticleBookBook ChapterConference PaperNewsletterOtherReportThesis

  Release Date (field_release_date)

  Year20232022202120202019201820172016201520142013201220112010200920082007200620052004200320022001200019991998199719961995

  Label

  April 10, 2021

  Nitrogen biogeochemistry in a boreal headwater stream network in interior Alaska

  High latitude, boreal watersheds are nitrogen (N)-limited ecosystems that export large amounts of organic carbon (C). Key controls on C cycling in these environments are the biogeochemical processes affecting the N cycle. A study was conducted in Nome Creek, an upland headwater tributary of the Yukon River, and two first-order tributaries to Nome Creek, to examine the relation between seasonal

  By

  Water Resources Mission Area

  October 31, 2019

  Reactive transport modeling to understand attenuation of arsenic concentrations in anoxic groundwater during Fe(II) oxidation by nitrate

  A previously published field-experimental investigation showed that injection of nitrate in anoxic groundwater that contained aqueous and sediment-bound Fe(II) diminished concentrations of As(V) and As(III) to below drinking-water limits. In the current study, reactive transport modeling confirmed that the observed attenuation was consistent with oxidation of Fe(II) by nitrate, leading to precipit

  By

  Water Resources Mission Area, Toxic Substances Hydrology, Environmental Health Program

  June 24, 2019

  Seasonal and spatial variation in the location and reactivity of a nitrate-contaminated groundwater discharge zone in a lakebed

  Groundwater discharge delivering anthropogenic N from surrounding watersheds can impact lake nutrient budgets. However, upgradient groundwater processes and changing dynamics in N biogeochemistry at the groundwater-lake interface are complex and difficult to resolve. In this study, hydrograph variations in a groundwater flow-through lake altered discharge patterns of a wastewater-derived, groun

  By

  Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, New England Water Science Center

  May 30, 2019

  Methane and nitrous oxide temporal and spatial variability in two midwestern USA streams containing high nitrate concentrations

  Concentrations and emissions of greenhouse gases CO2, CH4, and N2O commonly are examined individually in aquatic environments in which each is expected to be relatively important; however, their co-occurrence and dynamic interactions in fluvial settings could provide important information about their controlling biogeochemical processes and potential contributions to global climate change. Spatial

  By

  Water Resources Mission Area

  March 14, 2019

  Constraining the oxygen isotopic composition of nitrate produced by nitrification

  Measurements of the stable isotope ratios of nitrogen (15N/14N) and oxygen (18O/16O) in nitrate (NO3–) enable identification of sources, dispersal, and fate of natural and contaminant NO3– in aquatic environments. The 18O/16O of NO3– produced by nitrification is often assumed to reflect the proportional contribution of oxygen atom sources, water, and molecular oxygen, in a 2:1 ratio. Culture and s

  By

  Water Resources Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology

  September 23, 2016

  Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer

  Nitrate has become an increasingly abundant potential electron acceptor for Fe(II) oxidation in groundwater, but this redox couple has not been well characterized within aquifer settings. To investigate this reaction and some of its implications for redox-sensitive groundwater contaminants, we conducted an in situ field study in a wastewater-contaminated aquifer on Cape Cod. Long-term (15 year) ge

  March 11, 2016

  Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake

  The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water chemistry, seepage

  By

  Water Resources Mission Area, Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program, New England Water Science Center

  September 24, 2015

  Role of anaerobic ammonium oxidation (anammox) in nitrogen removal from a freshwater aquifer

  Anaerobic ammonium oxidation (anammox) couples the oxidation of ammonium with the reduction of nitrite, producing N2. The presence and activity of anammox bacteria in groundwater were investigated at multiple locations in an aquifer variably affected by a large, wastewater-derived contaminant plume. Anammox bacteria were detected at all locations tested using 16S rRNA gene sequencing and quantific

  By

  Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program

  January 1, 2015

  Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

  Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sedimen

  By

  Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program

  January 28, 2013

  Long-term groundwater contamination after source removal—The role of sorbed carbon and nitrogen on the rate of reoxygenation of a treated-wastewater plume on Cape Cod, MA, USA

  The consequences of groundwater contamination can remain long after a contaminant source has been removed. Documentation of natural aquifer recoveries and empirical tools to predict recovery time frames and associated geochemical changes are generally lacking. This study characterized the long-term natural attenuation of a groundwater contaminant plume in a sand and gravel aquifer on Cape Cod, Mas

  July 11, 2012

  Potential For Denitrification near Reclaimed Water Application Sites in Orange County, Florida, 2009

  The potential for denitrification was tested in water samples from four Upper Floridan aquifer wells near a reclaimed water application site, in west Orange County Florida, and two adjacent springs. Results of the study indicate that denitrifying bacteria are present in the groundwater and spring water samples, and that these bacteria can readily denitrify the waters when suitable geochemical cond

  By

  Water Resources Mission Area, Caribbean-Florida Water Science Center (CFWSC)

  March 15, 2012

  Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006-08

  A plume of contaminated groundwater extends from former disposal beds at the Massachusetts Military Reservation's wastewater-treatment plant toward Ashumet Pond, coastal ponds, and Vineyard Sound, Cape Cod, Massachusetts. Treated sewage-derived wastewater was discharged to the rapid-infiltration beds for nearly 60 years before the disposal site was moved to a different location in December 1995. W

  By

  New England Water Science Center

  Non-USGS Publications**

  Smith, R. L., Kent, D. B., Repert, D. A., and Böhlke, J.K., 2017, Anoxic nitrate reduction coupled with iron oxidation and attenuation of dissolved arsenic and phosphate in a sand and gravel aquifer, Geochim. Cosmochim. Acta, 196:102-120, doi: http//dx.doi.org/10.1016/j.gca.2016.09.025.

  **Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.