The recent commercial availability of in situ optical sensors, together with new techniques for data collection and analysis, provides the opportunity to monitor a wide range water-quality constituents on time scales which environmental conditions actually change. Of particular interest is application ultraviolet (UV) photometers determination nitrate concentrations rivers streams. variety UV sensors currently available differ several important ways related instrument design that affect...

Field evidence collected along two groundwater flow paths shows that anaerobic biodegradation naturally attenuates a plume of chlorinated volatile organic compounds as it discharges from an aerobic sand aquifer through wetland sediments. A decrease in concentrations parent contaminants, trichloroethylene (TCE) and 1,1,2,2‐tetrachloroethane (PCA), concomitant increase daughter products occurs upward the The 1,2‐dichloroethylene, vinyl chloride, 1,1,2‐trichloroethane, 1,2‐dichloroethane are...

Degradation reactions controlling the fate of 1,1,2,2-tetrachloroethane (PCA) in a freshwater tidal wetland that is discharge area for contaminated aquifer were investigated by combined field and laboratory study. Samples from nested piezometers porous-membrane sampling devices (peepers) showed PCA concentrations decreased less chlorinated daughter products formed as groundwater became increasingly reducing along upward flow paths through sediments. The cis trans isomers 1,2-dichloroethylene...

Groundwater samples have been collected in California as part of statewide investigations groundwater quality conducted by the U.S. Geological Survey for Ambient Monitoring and Assessment (GAMA) Priority Basin Project (PBP). The GAMA-PBP is being cooperation with State Water Resources Control Board to assess monitor resources used drinking-water supply improve public knowledge California. Quality-control (source-solution blanks, equipment field blanks) were order ensure sample results. Olsen...

A total of 2,541 constituents were evaluated and prioritized for national- regional-scale ambient monitoring water sediment in the United States. This prioritization was done by U.S. Geological Survey (USGS) preparation upcoming third decade (Cycle 3; 2013–23) National Water-Quality Assessment (NAWQA) Program. report provides methods used to prioritize results that prioritization. Constituents NAWQA Target Analyte Strategy (NTAS) work group on basis available information physical chemical...

The wide range of redox conditions and diversity microbial populations in organic-rich wetland sediments could enhance biodegradation chlorinated solvents. To evaluate potential rates trichloroethylene (TCE) its anaerobic daughter products (cis-1,2-dichloroethylene; trans-1,2-dichloroethylene; vinyl chloride), laboratory microcosms were prepared under methanogenic, sulfate-reducing, aerobic using sediment groundwater from a freshwater that is discharge area for TCE contaminant plume. Under...

Trace-element quality-control samples (for example, source-solution blanks, field and replicates) were collected as part of a statewide investigation groundwater quality in California, known the Priority Basins Project Groundwater Ambient Monitoring Assessment (GAMA) Program. The GAMA is being conducted by U.S. Geological Survey (USGS) cooperation with California State Water Resources Control Board (SWRCB) to assess monitor resources used for drinking-water supply improve public knowledge...

Volatile organic compounds (VOCs) were analyzed in quality-control samples collected for the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. From May 2004 through September 2010, a total of 2,026 groundwater samples, 211 field blanks, 109 source-solution blanks concentrations 85 VOCs. Results from analyses these 2,411 laboratory instrument during same time period used to assess quality data samples. Eighteen VOCs detected or blanks: acetone,...

First posted September 28, 2016 For additional information, contact: Chief, Water Science Field Team U.S. Geological Survey 520 North Park Avenue Tucson, Arizona 85721 http://az.water.usgs.gov/ Potential sources of analytical bias and error associated with laboratory analyses for selected trace elements where concentrations were greater in filtered samples than paired unfiltered evaluated by (USGS) Quality Specialists collaboration the USGS National Laboratory (NWQL) Branch Systems...

First posted May 16, 2019 For additional information, contact: Director, Lower Mississippi-Gulf Water Science Center U.S. Geological Survey640 Grassmere Park Drive Nashville, TN 37211 This report presents revised results for four parameters reported suspended-sediment samples that were collected in the lower Mississippi-Atchafalaya River Basin as part of a cooperative program between Army Corps Engineers, Mississippi Valley Division, New Orleans District and Survey (USGS). The has been...

The Field Contamination Study (FCS) was designed to determine the field processes that tend result in clean blanks and identify potential sources of contamination collected from selected volatile organic compounds (VOCs) wastewater-indicator (WICs). VOCs WICs analyzed FCS were detected by U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program during 1996–2008 2002–08, respectively. To minimize number variables, study required ordering supplies just before sampling,...

A natural-gradient ground-water tracer test was designed and conducted in a tidal freshwater wetland at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The objectives of the were to characterize solute transport site, obtain data more accurately determine velocity upper sediments, compare conservative, ionic (bromide) volatile (sulfur hexafluoride) ascertain whether volatilization could be an important process attenuating organic compounds ground water. within peat unit layer...

This report presents water-quality data for ground-water and surface-water samples water-level collected by the U.S. Geological Survey from October 1998 through September 1999 at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The also provides a description of sampling analytical methods that were used to collect analyze samples, includes an evaluation quality-assurance data. network 88 wells or piezometers, including four 2-inch wells, two 4-inch thirty 0.75-inch piezo-meters,...

This report presents lithologic and groundwater- quality data collected during April May 2000 in the remote areas of tidal wetland West Branch Canal Creek, Aberdeen Proving Ground, Maryland. Contamination Creek aquifer with volatile organic compounds has been documented previous investigations area. study was conducted to investigate that were previously inaccessible because deep mud shallow water, support ongoing fate transport aquifer. A unique vibracore drill rig mounted on a hovercraft...

In 1993, a study of pesticide movement and degradation in soils was intitated the Beaver Creek watershed, which consists about 95,000 acres includes some Nation's most highly erodible soils. Resource-management agencies this locality have recommended conservation tillage or "no-tillage" as best management practices to control soil erosion. The aldicarb selected for because it is both mobile extremely toxic. Horizontal its metabolites negligible. Vertical limited top 2.5 feet soil. Most...

This report presents ground-water and surface-water quality data from samples collected by the U.S. Geological Survey November 1999 through May 2001 at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The also provides a description of sampling analytical methods that were used to collect analyze samples, includes an evaluation quality-assurance data. network included two 4-inch wells, 2-inch sixteen 1-inch piezometers, one hundred thirteen 0.75-inch 0.25-inch flexible-tubing...