A5008731491- Groundwater and Isotope Geochemistry
- Water Quality and Resources Studies
- Groundwater flow and contamination studies
- Soil and Water Nutrient Dynamics
- Pesticide and Herbicide Environmental Studies
- Fish Ecology and Management Studies
- Water Quality and Pollution Assessment
- Mine drainage and remediation techniques
- Radioactive element chemistry and processing
- Environmental Toxicology and Ecotoxicology
- Pharmaceutical and Antibiotic Environmental Impacts
- Analytical chemistry methods development
- Hydrology and Watershed Management Studies
- Marine and coastal ecosystems
- Freshwater macroinvertebrate diversity and ecology
- Arsenic contamination and mitigation
- Aquatic Ecosystems and Phytoplankton Dynamics
- Mercury impact and mitigation studies
- Tailings Management and Properties
- Archaeology and Natural History
- Heavy Metal Exposure and Toxicity
- Radioactivity and Radon Measurements
- American Environmental and Regional History
- Microbial Fuel Cells and Bioremediation
- Pesticide Residue Analysis and Safety
United States Geological Survey
1995-2022
California Water Science Center
2022
Denver Federal Center
2008
United States Department of the Interior
1995
University of Waterloo
1984
An assessment of nitrate concentrations in groundwater the United States indicates that are highest shallow, oxic beneath areas with high N inputs. During 1991−2003, 5101 wells were sampled 51 study throughout U.S. as part Geological Survey National Water-Quality Assessment (NAWQA) program. The well networks reflect existing used resource represented by domestic major aquifers (major aquifer studies), and recently recharged dominant land-surface activities (land-use studies). Nitrate shallow...
National Findings and Their ImplicationsAlthough the use of artificial fertilizer has supported increasing food production to meet needs a growing population, increases in nutrient loadings from agricultural and, lesser extent, urban sources have resulted concentrations many streams parts aquifers that exceed standards for protection human health (or) aquatic life, often by large margins.Do NAWQA findings substantiate national concerns health?National Water-Quality Assessment (NAWQA)...
The distribution of microbially mediated terminal electron‐accepting processes (TEAPs( was investigated in four hydrologically diverse groundwater systems by considering patterns electron acceptor (nitrate, sulfate) consumption, intermediate product (hydrogen (H 2 )) concentrations, and final (ferrous iron, sulfide, methane) production. In each hydrologic system a determination predominant TEAPs could be arrived at, but the level confidence appropriate for differed. portion lacustrine...
The virtual ubiquity of fertilizer-fed agriculture, increasing over several decades, has become necessary to support the global human population. Ironically, widespread use nitrogen (N) contaminated another vital resource: surficial fresh groundwater. Further, as nitrous oxide (N2O) is a potent greenhouse gas, anthropogenic manipulation N budgets ramifications that can extend far beyond national borders. To get handle on size problem, Puckett et al. present an approach track historical...
Cyanotoxins occur in rivers worldwide but are understudied lotic ecosystems relative to lakes and reservoirs. We sampled 11 large river sites located throughout the United States during June–September 2017 determine occurrence of cyanobacteria with known cyanotoxin-producing strains, cyanotoxin synthetase genes, cyanotoxins. Chlorophyll a concentrations ranged from oligotrophic eutrophic (0.5–64.4 µg L−1). Cyanobacteria were present algal communities all (82% samples, n = 50) rarely...
Summary 1. Algal‐community metrics were calculated for periphyton samples collected from 976 streams and rivers by the U.S. Geological Survey’s National Water‐Quality Assessment (NAWQA) Programme during 1993–2001 to evaluate national regional relations with water chemistry compare whether algal‐metric values differ significantly among undeveloped developed land‐use classifications. 2. Algal significant positive correlations nutrient concentrations included indicators of trophic condition,...
Geochemical data obtained between 1979 and 1983 from a network of piezometer nests cores three inactive uranium tailings impoundments in the Elliot Lake district indicate that oxidation pyrite taking place shallow part zone above water table is causing chemistry pore below to change. A two-layer hydrochemical zonation has developed which infiltration rain snow resulted an upper low-pH with high concentrations SO 4 , Fe, heavy metals. This gradually expanding downward at rates generally 0.2 2...
Protection of ground water for present and future use requires monitoring understanding the mechanisms controlling long-term quality water. In this study, spatial temporal trends in concentrations nitrate pesticides eastern San Joaquin Valley, California, were evaluated to determine effects agricultural urban development on regional ground-water quality. Trends nitrate, nematocide 1,2-dibromo-3-chloropropane, herbicide simazine during last two decades are generally consistent with known...
A comprehensive national analysis of the distribution and trends nutrient concentrations in streams groundwater from 1992 through 2004 is provided by National Water-Quality Assessment (NAWQA) Program United States Geological Survey (USGS). Findings describe causes varying throughout Nation examine primary sources that contribute to elevated concentrations. Results show excessive enrichment a widespread cause ecological degradation nitrate contamination used for drinking water, particularly...
The presence of contaminants in a source water can constrain its suitability for drinking. quality groundwater used public supply was assessed 25 principal aquifers (PAs) that account 84% pumped the U.S. (89.6 million people on proportional basis). Each PA sampled across lateral extent using an equal-area grid, typically with 60 wells per PA. Samples were analyzed 502 constituents, which 374 had either regulatory or nonregulatory human health benchmark (HHB). Nationally, elevated...
This report is intended to summarize major findings that emerged between 1992 and 1995 from the water-quality assessment of San Joaquin-Tulare Basins Study Unit relate these issues regional national concern. The information primarily for those who are involved in water-resource management. Yet, contained here may also interest simply wish know more about quality water rivers aquifers area where they live.
Abstract Rainfall‐induced runoff mobilized pesticides to the San Joaquin River and its tributaries during a 3.8‐cm rainstorm beginning evening of 7 February lasting through morning 8 Feb. 1993. Two distinct peaks organophosphate pesticide concentrations were measured at mouth River. These two attributed contrasts between soil texture, basin size, pesticide‐use patterns, hydrology eastern western Valley. The fine texture small size tributary basins contributed rapid runoff. In valley streams,...
First posted September 29, 2016 Revised December 18, 2017 For additional information, contact: Coordinator, National Water Quality Program U.S. Geological Survey12201 Sunrise Valley DriveReston, VA 20192https://www.usgs.gov Cyanobacterial harmful algal blooms (CyanoHABs) are increasingly a global concern because CyanoHABs pose threat to human and aquatic ecosystem health cause economic damages. Despite advances in scientific understanding of cyanobacteria associated compounds, many...
Abstract Investigations of the geochemistry inactive pyritic uranium tailings in Elliot Lake Mining district Ontario have focused on Nordic management area, where two impoundments are located natural bedrock basins. The 8-12 m thick and overlie a localized deposit glaciofluvial sands. Analyses solid, liquid, gas phases vadose zone show that gas-phase oxygen levels drop rapidly within 0.7 to 1.5 surface, indicating rapid consumption during pyrite oxidation. Oxidation past 15 20 years has...
Hydrograph separation was used to determine the base-flow component of streamflow for 148 sites sampled as part National Water-Quality Assessment program. Sites in Southwest and Northwest tend have index values greater than 0.5. Midwest eastern portion Southern Plains generally less Base-flow Southeast Northeast are mixed with Hypothesized flow paths based on relative scaling soil bedrock permeability explain some differences found index. areas impermeable soils (areas where overland may be...
Abstract Simazine, diuron, and bromacil are the most frequently detected currently registered pesticides in California groundwater. These herbicides have been used for several decades Fresno Tulare counties, California; however, previous data inadequate to determine whether detections a result of recent or historical applications (i.e., within last decade, 20–30 yr ago). Chlorofluorocarbon (CFC) groundwater age‐dating was conjunction with one‐dimensional transport modeling address this...