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UNT College of Arts and Sciences
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Geography
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2010-2019
Nitrate and Chloride Concentrations in Groundwater beneath a Portion ofn the Trinity Group Outcrop Zone, Texas
Date: 2012
Creator: Hudak, Paul F.
Description: This article discusses nitrate and chloride concentrations in groundwater beneath a portion of the Trinity Group outcrop zone in Texas. Abstract: Using a geographic information system and statistics, the author evaluated spatial distributions of nitrate and chloride concentrations in groundwater in an area of north-central Texas with agricultural activity, in addition to oil and natural gas exploration and production. Data were compiled from 40 water wells sampled in 2007. Nitrate concentrations in three wells exceeded the maximum contaminant level (44 mg/L) for drinking water. The highest nitrate concentration was 149 mg/L, and concentrations were generally higher in shallower wells. Chloride concentrations exceeded the 250 mg/L secondary drinking water standard in two wells, with no significant association between chloride concentration and well depth. Results of this study suggest localized human impacts, especially for nitrate, and identify areas warranting future monitoring.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152435/
Geographic Distribution of HIV/AIDS in Texas
Date: December 1, 2011
Creator: Oppong, Joseph R.
Description: This presentation is part of the faculty lecture series UNT Speaks Out on HIV/AIDS. This presentation discusses the geographic distribution of HIV/AIDS in Texas and the associated factors.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc71783/
Potential Hazards of Wind Energy For Rare, Tereatened, and Endangered Birds and Batsin Texas
Date: 2011
Creator: Graham, T. L. & Hudak, Paul F.
Description: This article discusses the potential hazards of wind energy for rare, tereatened, and endangered birds and Batsin, Texas. The purpose of this study was to estimate relative potential hazard index (PHI) for 31 bird and ten bat species based upon the percentage of known or observed species range area (by county) within each wind speed classification. Results demonstrate considerable range in relative hazard, with the lesser prairie chicken and ferruginous hawk among the most potentially impacted birds; and the pale Townsend's bat, western small-footed bat, and big free-tailed bat among the most potentially impacted bats. While additional data are necessary to establish actual impacts of wind developments, relative potential hazard indices may help prioritize future studies.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152434/
Spatial Distribution of Solutes in Aquifer Outcrop Zones along the Brazos River, East-Central Texas
Date: 2011
Creator: Hudak, Paul F.
Description: This articles discusses the spatial distribution of solutes in Aquifer outcrop zones along the Brazos River in east-central, Texas. Concentrations of several solutes - nitrate, arsenic, sulfate, boron, chloride, and bromide - along with total dissolved solids (TDS) in ten counties bordering the Brazos River in east-central, Texas were compiled, mapped, and analyzed relative to regional land use and geology. Agriculture and oil/gas production are major activities and potential sources of groundwater contamination in the study area. Data were compiled from 104 water wells with a median depth of 446 ft (136 m) in the outcrop zones of six sedimentary aquifers: Carizzo-Wilcox, Queen City, Sparta, Yegua-Jackson, Gulf Coast, and Brazos Alluvium. Only two observations surpassed the 44.3 mg/L drinking water standard for nitrate, and four observations exceeded the 10 ug/L standard for arsenic. The median chloride concentration was 53 mg/L; however, the maximum level was almost three times the secondary drinking water standard of 250 mg/L. Chloride, bromide, sulfate, and boron concentrations resembled TDS patterns, with numerous samples exceeding secondary TDS drinking water standards in the Yegua-Jackson Aquifer. Most chloride/bromide ratios were between 100 and 300. Overall, results of this study suggest that natural processes exert a primary control on ...
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152433/
Nitrate, Arsenic and Selenium Concentrations in The Pecos Valley Aquifer, West Texas, USA
Date: 2010
Creator: Hudak, Paul F.
Description: This article discusses nitrate, arsenic, and selenium concentrations in the Pecos Valley Aquifer in west Texas. Abstract: Nitrate, arsenic, and selenium concentrations in the Pecos Valley Aquifer of west Texas compiled, mapped, and analyzed in the context of local geology and land use. Alluvial deposits of sand, silt, clay, and gravel compose the unconfined aquifer. Ranching and farming are predominant land uses in the rural study area. Data were tabulated from 79 water wells with a median depth of 75 m and mapped with a geographic information system (GIS). The wells were sampled between the years 2003 and 2008. Total dissolved solids (TDS) concentrations in the aquifer were very high, with a median value of 2,687 mg/L. Approximately 18% of observations exceeded the 44.27 mg/L drinking water standard for nitrate, whereas 6% exceeded the 10 μg/L standard for selenium. There was a statistically significant, direct correlation between arsenic and selenium, as well as between nitrate and selenium concentrations. Moreover, arsenic and selenium concentrations were significantly higher in shallower wells. Probable sources of groundwater contamination in the study area include natural (geological) sources and agricultural activity.
Contributing Partner: UNT College of Arts and Sciences
Permallink:digital.library.unt.edu/ark:/67531/metadc152432/