Identification_Information: Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2012 Title: Model-Predicted Probabilities of Arsenic Occurring in Pennsylvania Groundwater at Concentrations of 4 micrograms per liter or Greater (prob_as4_pa) Geospatial_Data_Presentation_Form: raster digital data Online_Linkage: http://pubs.usgs.gov/sir/2012/5257/ Larger_Work_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2012 Title: Arsenic concentrations, related environmental factors, and the predicted probability of elevated arsenic in groundwater in Pennsylvania Series_Information: Series_Name: U.S. Geological Survey Scientific Investigations Report Issue_Identification: 2012-5257 Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Other_Citation_Details: Gross, E.L., and Low, D.J., 2012, Arsenic concentrations, related environmental factors, and the predicted probability of elevated arsenic in groundwater in Pennsylvania: U.S. Geological Survey Scientific Investigations Report 2012-5257, XX p., at http://pubs.usgs.gov/sir/2012/5257. Online_Linkage: http://pubs.usgs.gov/sir/2012/5257/ Description: Abstract: Probabilities of arsenic occurrence in groundwater at concentrations greater than or equal to 4 micrograms per liter (ug/L) were predicted using multivariate logistic regression modeling developed for use by the Pennsylvania Environmental Public Health Tracking Program (PAEPHT). This dataset is in ESRI grid format with 100-meter cells and represents the model of arsenic concentrations occurring at or above 4 ug/L. About 1 percent of Pennsylvania groundwater was identified as having at least a 50 percent chance of containing an arsenic concentration greater than or equal to 4 ug/L. The northwestern counties of Crawford, Erie, and Forest have the greatest potential for having arsenic concentrations greater than or equal to 4 ug/L in groundwater. Significant predictors of arsenic in groundwater in Pennsylvania being greater than or equal to 4 ug/L included geologic, geochemical, and soil characteristic factors. Explanatory variables included (1) siliciclastic major aquifer type (1 = siliciclastic, 0 = all other), (2) surficial major aquifer type (1 = surficial, 0 = all other), (3) estimated groundwater specific conductance in microsiemens per centimeter (µS/cm), (4) estimated groundwater pH, and (5) average soil available water capacity in percent (%). More than 40 statewide individual predictor variables were assembled for this study and tested as potential predictor variables for the model. More than 5,000 individual measurements of arsenic concentration from a combination of public and private water-supply wells served as the dependent (or predicted) variable in the model. Purpose: In many areas worldwide, including Pennsylvania, drinking water is the primary route of human exposure to arsenic. Arsenic data are sparse for groundwater because statewide testing of private wells to determine where concentrations exceed the health-based maximum contaminant level (MCL) of 10.0 micrograms per liter (µg/L) for drinking water, established in 2001 by the U.S. Environmental Protection Agency (USEPA), is not required throughout Pennsylvania. Domestic wells used for private water supplies in Pennsylvania are not required to be routinely tested for arsenic and other contaminants, so homeowners may not know whether their well water has arsenic concentrations greater than the MCL. An arsenic probability model was developed for the Pennsylvania Environmental Public Health Tracking (PA EPHT) Program to predict the probability of arsenic concentrations greater than or equal to 4 µg/L occurring in groundwater throughout the State. The PAEPHT Program is part of the National Environmental Public Health Tracking Program funded by the Centers for Disease Control and Prevention (CDC) to improve public health by providing science-based information about the presence of and trends in environmentally related diseases. A focus area for the PAEPHT Program is that of understanding the occurrence of arsenic in both public and private drinking-water supplies throughout the State. The geospatial data representing the probability model can be used as a tool for resource decision-making and risk assessment. This dataset is available from the USGS at http://pubs.usgs.gov/sir/2012/5257/ and is intended to be available through the online databases of the CDC and the PAEPHT programs. Supplemental_Information: This work was performed under the collaborative sub-grant 5U38EH000191-4 from the Pennsylvania Environmental Public Health Tracking (PA EPHT) program of the Pennsylvania Department of Health, Bureau of Epidemiology and the Pennsylvania Department of Environmental Protection. Others involved with data and model review: Scott A. Hoffman, dataset and model reviewer, U.S. Geological Survey, Pennsylvania Water Science Center, New Cumberland, Pennsylvania Lisa A. Senior, model reviewer, U.S. Geological Survey, Pennsylvania Water Science Center, Exton, Pennsylvania Joseph D. Ayotte, model reviewer, U.S. Geological Survey, New Hampshire Water Science Center, Pembroke, New Hampshire Dennis W. Risser, model reviewer, U.S. Geological Survey, Pennsylvania Water Science Center, New Cumberland, Pennsylvania Bruce D. Lindsey, model reviewer, U.S. Geological Survey, Pennsylvania Water Science Center, New Cumberland, Pennsylvania Charles A. Cravotta III, model reviewer, U.S. Geological Survey, Pennsylvania Water Science Center, New Cumberland, Pennsylvania Kevin J. Breen, model reviewer, U.S. Geological Survey, Pennsylvania Water Science Center, New Cumberland, Pennsylvania Robert C. Smith II, geologic and geochemical interpretation, Pennsylvania Department of Conservation and Natural Resources, Pennsylvania Geological Survey, Middletown, Pennsylvania Jayanth K. Devasundaram, dataset reviewer, Pennsylvania Department of Health, Bureau of Epidemiology, Environmental Public Health Tracking, Harrisburg, Pennsylvania Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20121010 Currentness_Reference: Model completed Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -80.617747 East_Bounding_Coordinate: -74.616103 North_Bounding_Coordinate: 42.284942 South_Bounding_Coordinate: 39.673150 Keywords: Theme: Theme_Keyword_Thesaurus: SAS Institute, 1990, SAS/STAT user's guide: Cary, NC., SAS Institute, Inc., 1,686 p. Theme_Keyword: Logistic regression Theme_Keyword: Modeling Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Categories Theme_Keyword: arsenic Theme_Keyword: probability modeling Theme_Keyword: logistic regression Theme_Keyword: groundwater Theme_Keyword: human health Theme_Keyword: drinking water Theme_Keyword: domestic wells Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Pennsylvania, United States Place: Stratum: Stratum_Keyword_Thesaurus: None Stratum_Keyword: None Temporal: Temporal_Keyword_Thesaurus: None Temporal_Keyword: None Access_Constraints: None Use_Constraints: The statewide probability model is not designed to predict arsenic concentration in any single well, but it is expected to provide useful information in areas of the State that currently contain little to no data on arsenic concentration. It is intended to provide statistical estimates of the chance of having concentrations of arsenic greater than or equal to 4 ug/L in groundwater. Although the probability grid can be useful to water-resource managers to identify areas that can benefit from increased monitoring or to identify populations at risk, the model cannot determine which individual wells will be at risk. Only testing of individual wells for concentrations of arsenic in the groundwater can reliably provide that level of information. The scales of the data that went into the models vary from 1:24,000 to 1:250,000; therefore, the use of the data at larger scales may not represent conditions at specific locations. Data_Set_Credit: U.S. Geological Survey, Pennsylvania Water Science Center, Eliza L. Gross Security_Information: Security_Classification_System: None Security_Classification: Unclassified Native_Data_Set_Environment: Microsoft Windows Vista Version 6.1 (Build 7600) ; ESRI ArcCatalog 9.3.1.3000 Cross_Reference: Citation_Information: Originator: Langland, M.J. Originator: Dugas, D.L. Publication_Date: 1996 Title: Assessment of severity and distribution of corrosive ground water in Pennsylvania Series_Information: Series_Name: Open-File Report Issue_Identification: 95-377 Publication_Information: Publication_Place: New Cumberland, PA Publisher: U.S. Geological Survey Other_Citation_Details: Langland, M.J. and Dugas, D.L., 1996, Assessment of severity and distribution of corrosive ground water in Pennsylvania: U.S. Geological Survey Open-File Report 95-377, 2 p. Cross_Reference: Citation_Information: Originator: Low, D.J. Originator: Chichester, D.C. Publication_Date: 2006 Title: Ground-water-quality data in Pennsylvania - A compilation of computerized [electronic] databases, 1979-2004 Series_Information: Series_Name: Data Series Issue_Identification: 150 Publication_Information: Publication_Place: New Cumerland, PA Publisher: U.S. Geological Survey Other_Citation_Details: Low, D.J. and Chichester, D.C., 2006, Ground-water-quality data in Pennsylvania - A compilation of computerized [electronic] databases, 1979-2004: U.S. Geological Survey Data Series 150, 22 p. 1 CD. Online_Linkage: http://pubs.usgs.gov/ds/ds150/ Cross_Reference: Citation_Information: Originator: Pennsylvania Geological Survey Publication_Date: 2001 Title: Bedrock geology of Pennsylvania Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: digital data Publication_Information: Publication_Place: Harrisburg, PA Publisher: Pennsylvania Geological Survey Other_Citation_Details: Pennsylvania Geological Survey, 2001, Bedrock geology of Pennsylvania: Pennsylvania Geological Survey, digital data, accessed June 23, 2008, at http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx Online_Linkage: http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx Cross_Reference: Citation_Information: Originator: Lindsey, B.D Originator: Bickford, T.M. Publication_Date: 1999 Title: Hydrogeologic framework and sampling design for an assessment of agricultural pesticides in ground water in Pennsylvania Publication_Information: Publication_Place: Lemoyne, PA Publisher: U.S. Geological Survey Other_Citation_Details: Lindsey, B.D. and T.M. Bickford, 1999, Hydrogeologic framework and sampling design for an assessment of agricultural pesticides in ground water in Pennsylvania: U.S. Geological Survey, Water-Resources Investigation Report 99-4076, 49 p. Cross_Reference: Citation_Information: Originator: Soller, D.R. Originator: Packard, P.H. Publication_Date: 1998 Title: Digital representation of a map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Soller, D.R., and Packard, P.H., 1998, Digital representation of a map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains: U.S. Geological Survey Digital Data Series DDS-38, 1 CD. Cross_Reference: Citation_Information: Originator: U.S. Bureau of the Census Publication_Date: 1990 Title: 1990 county & county equivalent areas [digital data] Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: digital data Publication_Information: Publication_Place: Washington, D.C. Publisher: U.S. Bureau of the Census Other_Citation_Details: U.S. Bureau of the Census, 1990, 1990 county & county equivalent areas [digital data]: accessed June 11, 2008, at http://www.census.gov/geo/www/cob/co1990.html Online_Linkage: http://www.census.gov/geo/www/cob/co1990.html Cross_Reference: Citation_Information: Originator: U.S. Bureau of the Census Publication_Date: 1990 Title: 1990 state & state equivalent areas [digital data] Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: digital data Publication_Information: Publication_Place: Washington, D.C. Publisher: U.S. Bureau of the Census Other_Citation_Details: U.S. Bureau of the Census, 1990, 1990 state & state equivalent areas [digital data]: accessed June 11, 2008, at http://www.census.gov/geo/www/cob/st1990.html Online_Linkage: http://www.census.gov/geo/www/cob/st1990.html Cross_Reference: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2004 Title: National Uranium Resource Evaluation (NURE) hydrogeochemical and stream sediment reconnaissance data Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: digital data Publication_Information: Publisher: U.S. Geological Survey Other_Citation_Details: U.S. Geological Survey, 2004, National Uranium Resource Evaluation (NURE) hydrogeochemical and stream sediment reconnaissance data: U.S. Geological Survey, digital data, accessed September 29, 2008, at http://tin.er.usgs.gov/nure/sediment/ Online_Linkage: http://tin.er.usgs.gov/nure/sediment/ Cross_Reference: Citation_Information: Originator: Wolock, D.M. Publication_Date: 1997 Title: STATSGO soil characteristics for the conterminous United States Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Open-File Report Issue_Identification: 656 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Wolock, D.M., 1997, STATSGO soil characteristics for the conterminous United States: U.S. Geological Survey Open-File Report 656, digital data, accessed May 28, 2008, at http://water.usgs.gov/GIS/metadata/usgswrd/XML/muid.xml Online_Linkage: http://water.usgs.gov/GIS/metadata/usgswrd/XML/muid.xml Cross_Reference: Citation_Information: Originator: SAS Institute Publication_Date: 1990 Title: SAS/STAT user's guide Publication_Information: Publication_Place: Cary, NC Publisher: SAS Institute, Inc. Other_Citation_Details: SAS Institute, 1990, SAS/STAT user's guide: Cary, NC., SAS Institute, Inc., 1,686 p. Cross_Reference: Citation_Information: Originator: Nakagaki, N., Price, C.V., Falcone, J.A., Hitt, K.J., Ruddy, B.C. Publication_Date: 2007 Title: Enhanced national land cover data 1992 (NLCDe 92) Geospatial_Data_Presentation_Form: raster digital data Publication_Information: Publisher: U.S. Geological Survey Other_Citation_Details: Nakagaki, N., Price, C.V., Falcone, J.A., Hitt, K.J., Ruddy, B.C., 2007, Enhanced national land cover data 1992 (NLCDe 92): U.S. Geological Survey, digital data, accessed March 31, 2008, at http://water.usgs.gov/GIS/metadata/usgswrd/XML/nlcde92.xml Online_Linkage: http://water.usgs.gov/GIS/metadata/usgswrd/XML/nlcde92.xml Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: No attributes within floating-point raster dataset. Quantitative_Attribute_Accuracy_Assessment: Attribute_Accuracy_Value: VALUE Attribute_Accuracy_Explanation: Values indicate the predicted probability of elevated (greater than 4 micrograms per liter) arsenic concentrations in groundwater, in percent. "No data" values indicate areas where there are no modeled data. Logical_Consistency_Report: Dataset is a floating-point raster format. Completeness_Report: This dataset is complete for the modeled area, which includes the state of Pennsylvania, with regard to datasets used in the development. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Dataset is accurate at a scale of 1:250,000. The threshold accuracy value for a scale of 1:250,000, as established by National Map Accuracy Standards, is 127 meters (417 feet) in ground units. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Not Applicable Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Langland, M.J. Originator: Dugas, D.L. Publication_Date: 1996 Title: Assessment of severity and distribution of corrosive ground water in Pennsylvania Geospatial_Data_Presentation_Form: Open-File Report Series_Information: Series_Name: Open-File Report Issue_Identification: 95-377 Publication_Information: Publication_Place: New Cumberland, PA Publisher: U.S. Geological Survey Other_Citation_Details: Langland, M.J. and Dugas, D.L., 1996, Assessment of severity and distribution of corrosive ground water in Pennsylvania: U.S. Geological Survey Open-File Report 95-377, 2 p. Source_Scale_Denominator: 1:250,000 Type_of_Source_Media: Open-File Report Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1996 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (Langland and Dugas, 1996) Source_Contribution: This source contributed maps that were used to create boundaries defining areas with different groundwater corrosivity rankings. These boundaries were used in the creation of the inverse distance weighted interpolation of specific conductance and pH groundwater quality variables. Source_Information: Source_Citation: Citation_Information: Originator: Low, D.J. Originator: Chichester, D.C. Publication_Date: 2006 Title: Ground-water-quality data in Pennsylvania - A compilation of computerized [electronic] databases, 1979-2004 Geospatial_Data_Presentation_Form: Point digital data Series_Information: Series_Name: Data Series Issue_Identification: 150 Publication_Information: Publication_Place: New Cumberland, PA Publisher: U.S. Geological Survey Other_Citation_Details: Low, D.J. and Chichester, D.C., 2006, Ground-water-quality data in Pennsylvania - A compilation of computerized [electronic] databases, 1979-2004: U.S. Geological Survey Data Series 150, 22 p. 1 CD. Online_Linkage: http://pubs.usgs.gov/ds/ds150/ Source_Scale_Denominator: 1:24,000 Type_of_Source_Media: Point digital data Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2006 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (Low and Chichester, 2006) Source_Contribution: This source contributed arsenic groundwater-quality data used to predict the probability of elevated (greater than or equal to 4 ppb) arsenic concentrations in groundwater in Pennsylvania. This source also contributed specific conductance and pH groundwater-quality data that were used in the creation of the inverse distance weighted interpolation of specific conductance and pH groundwater quality variables. Source_Information: Source_Citation: Citation_Information: Originator: Pennsylvania Geological Survey Publication_Date: 2001 Title: Bedrock geology of Pennsylvania Geospatial_Data_Presentation_Form: vector digital data Publication_Information: Publication_Place: Harrisburg, PA Publisher: Pennsylvania Geological Survey Other_Citation_Details: Pennsylvania Geological Survey, 2001, Bedrock geology of Pennsylvania: Pennsylvania Geological Survey, digital data, accessed June 23, 2008, at http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx Online_Linkage: http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx Source_Scale_Denominator: 1:250,000 Type_of_Source_Media: Vector digital data Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2001 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (Pennsylvania Geological Survey, 2001) Source_Contribution: This source contributed "Bedrock Geology of Pennsylvania" digital data (Pennsylvania Geological Survey, 2001) used to create variables describing four major aquifers of Pennsylvania: (1) carbonate, (2) crystalline, (3) siliciclastic, and (4) surficial. These four geologic variables were modeled as discrete variables by performing a spatial intersection with mapped geologic units across the State to assign each well with associated arsenic groundwater-quality data to a major aquifer. The discrete major aquifer variables were coded as “one” if a well was located in a particular major aquifer and coded as “zero” if the well was not located in an aquifer. For example, the carbonate major aquifer variable would code all wells spatially intersecting carbonate aquifers as “one” and all wells spatially intersecting the other major aquifers (crystalline, siliciclastic, and surficial) as “zero.” Mapped geologic units in Pennsylvania were divided by major aquifers according to their reported primary lithology descriptions (Pennsylvania Geological Survey, 2001). Carbonate bedrock aquifers consist of primary lithologies of argillaceous dolomite, argillaceous limestone, dolomite, graphitic marble, high-calcium limestone, limestone, limestone conglomerate, marble, and shaly limestone. Crystalline bedrock aquifers consist of primary lithologies of albite-chlorite schist, andesite, anorthosite, chlorite-sericite schist, diabase, feldspathic quartzite, felsic gneiss, granitic gneiss, granitic pegmatite, graphitic felsic gneiss, graphitic gneiss, greenstone schist, mafic gneiss, metabasalt, metadiabase, metagabbro, metarhyolite, oligoclase-mica schist, phyllite, quartzite, serpentinite, and slate. Siliciclastic bedrock aquifers consist of primary lithologies of argillaceous sandstone, argillite, arkosic sandstone, black shale, calcareous sandstone, calcareous shale, graywacke, mudstone, quartz conglomerate, quartzite, sandstone, shale, siliceous sandstone, siltstone, and silty mudstone. Surficial aquifers for mapped geologic units consist of primary lithologies of feldspathic quartz sand, ferruginous clay, gravelly sand, and sand. Additionally, bedrock aquifers in some areas of the State are overlain by unconsolidated material (Lindsey and Bickford, 1999; Soller and Packard, 1998) of sufficient depths to serve as an aquifer. These additional areas of the State where surficial materials consist of coarse-grained sediments were designated as surficial aquifers for this report and are indicated in Appendix 1 of SIR 2012-5257. "Bedrock Geology of Pennsylvania" digital data (Pennsylvania Geological Survey, 2001) were also used as the framework for assigning groundwater corrosivity rankings to geologic units according to maps created by Langland and Dugas in their 1996 report. These rankings provided boundaries that were used in the inverse distance weighted interpolation of specific conductance and pH groundwater quality variables. Source_Information: Source_Citation: Citation_Information: Originator: Lindsey, B.D. Originator: Bickford, T.M. Publication_Date: 1999 Title: Hydrogeologic framework and sampling design for an assessment of agricultural pesticides in ground water in Pennsylvania Geospatial_Data_Presentation_Form: Scientific Investigations Report Publication_Information: Publication_Place: Lemoyne, PA Publisher: U.S. Geological Survey Other_Citation_Details: Lindsey, B.D. and T.M. Bickford, 1999, Hydrogeologic framework and sampling design for an assessment of agricultural pesticides in ground water in Pennsylvania: U.S. Geological Survey, Water-Resources Investigation Report 99-4076, 49 p. Source_Scale_Denominator: 1:250,000 Type_of_Source_Media: Scientific Investigations Report Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1999 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (Lindsey and Bickford, 1999) Source_Contribution: This source contributed to the data used to create variables describing four major aquifers of Pennsylvania: (1) carbonate, (2) crystalline, (3) siliciclastic, and (4) surficial. This source provided a map indicating bedrock aquifers in some areas of the State that are overlain by unconsolidated material (Lindsey and Bickford, 1999; Soller and Packard, 1998) of sufficient depths to serve as an aquifer. These additional areas of the State where surficial materials consist of coarse-grained sediments were designated as surficial aquifers for this report and are indicated in Appendix 1 of SIR 2012-5257. Source_Information: Source_Citation: Citation_Information: Originator: Soller, D.R. Originator: Packard, P.H. Publication_Date: 1998 Title: Digital representation of a map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains Geospatial_Data_Presentation_Form: Polygon digital data Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Soller, D.R., and Packard, P.H., 1998, Digital representation of a map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains: U.S. Geological Survey Digital Data Series DDS-38, 1 CD. Source_Scale_Denominator: 1:1,000,000 Type_of_Source_Media: Polygon digital data Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1998 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (Soller and Packard, 1998) Source_Contribution: This source contributed to the data used to create variables describing four major aquifers of Pennsylvania: (1) carbonate, (2) crystalline, (3) siliciclastic, and (4) surficial. This source provided a polygon digital data indicating bedrock aquifers in some areas of the State that are overlain by unconsolidated material (Lindsey and Bickford, 1999; Soller and Packard, 1998) of sufficient depths to serve as an aquifer. These additional areas of the State where surficial materials consist of coarse-grained sediments were designated as surficial aquifers for this report and are indicated in Appendix 1 of SIR 2012-5257. Source_Information: Source_Citation: Citation_Information: Originator: U.S. Geological Survey Publication_Date: 2004 Title: Uranium Resource Evaluation (NURE) hydrogeochemical and stream sediment reconnaissance data Geospatial_Data_Presentation_Form: Point digital data Publication_Information: Publisher: U.S. Geological Survey Other_Citation_Details: U.S. Geological Survey, 2004, National Uranium Resource Evaluation (NURE) hydrogeochemical and stream sediment reconnaissance data: U.S. Geological Survey, digital data, accessed September 29, 2008, at http://tin.er.usgs.gov/nure/sediment/ Online_Linkage: http://tin.er.usgs.gov/nure/sediment/ Source_Scale_Denominator: 1:24,000 Type_of_Source_Media: Point digital data Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2004 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (U.S. Geological Survey, 2004) Source_Contribution: This source contributed specific conductance and pH hydrogeochemical groundwater quality data that were used in the creation of the inverse distance weighted interpolation of specific conductance and pH groundwater quality variables. Source_Information: Source_Citation: Citation_Information: Originator: Wolock, D.M. Publication_Date: 1997 Title: STATSGO soil characteristics for the conterminous United States Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: Open-File Report Issue_Identification: 656 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Other_Citation_Details: Wolock, D.M., 1997, STATSGO soil characteristics for the conterminous United States: U.S. Geological Survey Open-File Report 656, digital data, accessed May 28, 2008, at http://water.usgs.gov/GIS/metadata/usgswrd/XML/muid.xml Online_Linkage: http://water.usgs.gov/GIS/metadata/usgswrd/XML/muid.xml Source_Scale_Denominator: 1:250,000 Type_of_Source_Media: Raster digital data Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1997 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (Wolock, 1997) Source_Contribution: This source contributed the available water capacity soil characterization data. Source_Information: Source_Citation: Citation_Information: Originator: U.S. Bureau of the Census Publication_Date: 1990 Title: 1990 state & state equivalent areas [digital data] Geospatial_Data_Presentation_Form: vector digital data Publication_Information: Publication_Place: Washington, D.C. Publisher: U.S. Bureau of the Census Other_Citation_Details: U.S. Bureau of the Census, 1990, 1990 state & state equivalent areas [digital data]: accessed June 11, 2008, at http://www.census.gov/geo/www/cob/st1990.html Online_Linkage: http://www.census.gov/geo/www/cob/st1990.html Source_Scale_Denominator: 1:100,000 Type_of_Source_Media: Vector digital data Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1990 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (U.S. Bureau of the Census, 1990) Source_Contribution: The Pennsylvania state boundary was extracted from this source and used to clip other datasets to the study area size. Source_Information: Source_Citation: Citation_Information: Originator: Nakagaki, N., Price, C.V., Falcone, J.A., Hitt, K.J., Ruddy, B.C. Publication_Date: 2007 Title: Enhanced national land cover data 1992 (NLCDe 92) Geospatial_Data_Presentation_Form: raster digital data Publication_Information: Publisher: U.S. Geological Survey Other_Citation_Details: Nakagaki, N., Price, C.V., Falcone, J.A., Hitt, K.J., Ruddy, B.C., 2007, Enhanced national land cover data 1992 (NLCDe 92): U.S. Geological Survey, digital data, accessed March 31, 2008, at http://water.usgs.gov/GIS/metadata/usgswrd/XML/nlcde92.xml Online_Linkage: http://water.usgs.gov/GIS/metadata/usgswrd/XML/nlcde92.xml Source_Scale_Denominator: 1:24,000 Type_of_Source_Media: Raster digital data Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2007 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: (Nakagaki and others, 2007) Source_Contribution: This source was used as a snap raster in order to ensure the cell alignment of each output raster would be the same. Process_Step: Process_Description: The following explanatory variable datasets and their associated data were obtained and/or created according to the following methods described in the next four process steps: (1) siliciclastic major aquifer type (1 = siliciclastic, 0 = all other), (2) surficial major aquifer type (1 = surficial, 0 = all other), (3) estimated groundwater specific conductance (µS/cm), (4) estimated groundwater pH, and (5) average soil available water capacity (%). Source_Used_Citation_Abbreviation: (Pennsylvania Geological Survey, 2001) Source_Used_Citation_Abbreviation: (U.S. Geological Survey, 2004) Source_Used_Citation_Abbreviation: (Geyer and Wilshusen, 1982) Source_Used_Citation_Abbreviation: (Low and Chichester, 2006) Source_Used_Citation_Abbreviation: (Langland and Dugas, 1996) Source_Used_Citation_Abbreviation: (Wolock, 1997) Process_Date: 2010 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: 1.) Major aquifers of Pennsylvania: (1) carbonate, (2) crystalline, (3) siliciclastic, and (4) surficial -- "Bedrock Geology of Pennsylvania" digital data (Pennsylvania Geological Survey, 2001) were used for dividing geologic units according to their primary lithology. The four resulting geologic variables were modeled as discrete variables by performing a spatial intersection with mapped geologic units across the State to assign each well with associated arsenic groundwater-quality data to a major aquifer. The discrete major aquifer variables were coded as “one” if a well was located in a particular major aquifer and coded as “zero” if the well was not located in an aquifer. For example, the carbonate major aquifer variable would code all wells spatially intersecting carbonate aquifers as “one” and all wells spatially intersecting the other major aquifers (crystalline, siliciclastic, and surficial) as “zero.” Mapped geologic units in Pennsylvania were divided by major aquifers according to their reported primary lithology descriptions (Pennsylvania Geological Survey, 2001). Carbonate bedrock aquifers consist of primary lithologies of argillaceous dolomite, argillaceous limestone, dolomite, graphitic marble, high-calcium limestone, limestone, limestone conglomerate, marble, and shaly limestone. Crystalline bedrock aquifers consist of primary lithologies of albite-chlorite schist, andesite, anorthosite, chlorite-sericite schist, diabase, feldspathic quartzite, felsic gneiss, granitic gneiss, granitic pegmatite, graphitic felsic gneiss, graphitic gneiss, greenstone schist, mafic gneiss, metabasalt, metadiabase, metagabbro, metarhyolite, oligoclase-mica schist, phyllite, quartzite, serpentinite, and slate. Siliciclastic bedrock aquifers consist of primary lithologies of argillaceous sandstone, argillite, arkosic sandstone, black shale, calcareous sandstone, calcareous shale, greywacke, mudstone, quartz conglomerate, quartzite, sandstone, shale, siliceous sandstone, siltstone, and silty mudstone. Surficial aquifers for mapped geologic units consist of primary lithologies of feldspathic quartz sand, ferruginous clay, gravelly sand, and sand. Additionally, bedrock aquifers in some areas of the State are overlain by unconsolidated material (Lindsey and Bickford, 1999; Soller and Packard, 1998) of sufficient depths to serve as an aquifer. These additional areas of the State where surficial materials consist of coarse-grained sediments were designated as surficial aquifers for this report and are indicated in Appendix 1 of SIR 2012-5257. The geologic unit shapefile was converted from a feature to a raster four different times to create four raster datasets describing presence (1) or absence (0) of each of the major aquifer types (carbonate, crystalline, siliciclastic, surficial). Only the siliclastic and surficial raster major aquifer datasets were included in the final model. Source_Used_Citation_Abbreviation: (Pennsylvania Geological Survey, 2001) Source_Used_Citation_Abbreviation: (Lindsey and Bickford, 1999) Source_Used_Citation_Abbreviation: (Soller and Packard, 1998) Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: 2.) Estimated groundwater specific conductance -- Specific conductance groundwater quality data were obtained from a U.S. Geological Survey data series compiled by Low and Chichester in 2006 and from 2004 U.S. Geological Survey National Uranium Resource Evaluation hydrogeochemical reconnaissance data. These groundwater quality data were used to interpolate a surface using an inverse distance weighted (IDW) technique to calculate statewide specific conductance groundwater concentrations. This process was performed for each grouping of geologic units according to groundwater corrosivity rankings (Langland and Dugas, 1996). A dataset depicting groundwater corrosivity rankings was recreated by grouping geologic units (Pennsylvania Geological Survey, 2001) into appropriate rankings based on the resulting map from the Langland and Dugas (1996) open-file report. Since there are 12 different rankings in the state, a separate IDW surface was calculated for each grouping of units. All of the surfaces were then mosaiced into a statewide raster dataset using a mosaic tool in ArcMap. Source_Used_Citation_Abbreviation: (Pennsylvania Geological Survey, 2001) Source_Used_Citation_Abbreviation: (U.S. Geological Survey, 2004) Source_Used_Citation_Abbreviation: (Low and Chichester, 2006) Source_Used_Citation_Abbreviation: (Langland and Dugas, 1996) Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: 3.) Average soil available water capacity -- Average soil available water capacity data (Wolock, 1997) were related to mapping unit identification numbers within ArcMap in order to create the available water capacity dataset. Source_Used_Citation_Abbreviation: (Wolock, 1997) Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: 4.) Estimated groundwater hydrogen ion concentration as pH -- Groundwater quality data for pH were obtained from a U.S. Geological Survey data series compiled by Low and Chichester in 2006 and from 2004 U.S. Geological Survey National Uranium Resource Evaluation hydrogeochemical reconnaissance data. These groundwater quality data were used to interpolate a surface using an inverse distance weighted (IDW) technique to calculate statewide pH groundwater concentrations. This process was performed for each grouping of geologic units according to groundwater corrosivity rankings (Langland and Dugas, 1996). A dataset depicting groundwater corrosivity rankings was recreated by grouping geologic units (Pennsylvania Geological Survey, 2001) into appropriate rankings based on the resulting map from the Langland and Dugas (1996) open-file report. Since there are 12 different rankings in the state, a separate IDW surface was calculated for each grouping of units. Each of the interpolated surfaces were then mosaiced into a statewide raster dataset using a mosaic tool in ArcMap. Source_Used_Citation_Abbreviation: (Pennsylvania Geological Survey, 2001) Source_Used_Citation_Abbreviation: (U.S. Geological Survey, 2004) Source_Used_Citation_Abbreviation: (Low and Chichester, 2006) Source_Used_Citation_Abbreviation: (Langland and Dugas, 1996) Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: Explanatory variable datasets were clipped to the state of Pennsylvania's political boundary (U.S. Bureau of the Census, 1990) and snapped to a common dataset (Nakagaki and others, 2007). Each variable was compiled within 30-meter grid cells for estimating the probability of elevated arsenic in groundwater in Pennsylvania. The grid layers line up with a template representing the state of Pennsylvania consisting of 9,493 rows and 16,508 columns, which totals 156,710,444 cells with each containing data. Each cell measures 30-meters by 30-meters. Environmental settings within ArcMap enabled converted, created, and existing raster data for each variable to be clipped to the Pennsylvania state boundary (U.S. Bureau of the Census, 1990) and snapped to a common 30-meter grid, which consisted of a land cover dataset (Nakagaki and others, 2007). The snap raster ensured that the cell alignment of each output raster would be the same. Source_Used_Citation_Abbreviation: (U.S. Bureau of the Census, 1990) Source_Used_Citation_Abbreviation: (Nakagaki and others, 2007) Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: Explanatory variable data were extracted for each well within the dependent dataset. Explanatory data were extracted for each well using the "extract by points" tool in ArcMap in order to extract the data from the raster datasets using a set of points. Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: The logistic regression model was developed using SAS statistical software (SAS Institute, 1990) with data extracted for 5,009 wells and contains the following variables: (1) siliciclastic major aquifer type (1 = siliciclastic, 0 = all other) [SIL] (Estimated coefficient: 0.2327, Wald p-value: <0.0001), (2) surficial major aquifer type (1 = surficial, 0 = all other) [SURF] (Estimated coefficient: 0.2289, Wald p-value: <0.0001), (3) estimated groundwater specific conductance (µS/cm) [SPCIDW] (Estimated coefficient: 0.2071, Wald p-value: <0.0001), (4) estimated groundwater pH [PHIDW] (Estimated coefficient: 0.1722, Wald p-value: <0.0001), and (5) average soil available water capacity (%) [AWCAVE] (Estimated coefficient: -0.1417, Wald p-value: <0.0001). Source_Used_Citation_Abbreviation: (SAS Institute, 1990) Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: The statewide probability dataset was created. In order to make the statewide probability map depicting the predicted probability of elevated arsenic concentrations in groundwater in Pennsylvania, the values from the 30-m grid cells for each explanatory variable are put into the logistic regression model equation in the Raster Calculator using the Spatial Analyst extension. The following model equation is a Map Algebra expression using a combination of the resulting model coefficients and geospatial layers, which represent the explanatory variables. Refer to Table 5 of Scientific Investigations Report 2012-5257 (http://pubs.usgs.gov/sir/2012/5257/) for a complete list of model variables. PROB_AS4_PA = 1 / ( 1 + (Exp( - ( -4.1987 + ( 0.8697 * [SIL] ) + ( 1.4432 * [SURF] ) + ( 0.000701 * [SPCIDW]) + ( 0.4189 * [PHIDW]) + ( -11.3568 * [AWCAVE] ))))). This process calculates the probability that arsenic in groundwater exceeds 4 micrograms per liter for each cell as a fraction. Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: The units for the statewide probability dataset were converted from fraction to percentage. The "times" tool in the Spatial Analyst math toolbox was used to multiply the values of the statewide probability dataset by a constant value of 100 in order to convert the dataset units from fraction to percentage. Dataset units were converted from fraction to percentage in order to produce a probability dataset with units that are consistent with those units used for resulting probability datasets produced by similar studies. Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: The resolution of the statewide probability dataset was reduced by aggregating the dataset. The "aggregate" tool within the Spatial Analyst generalization toolbox was used to generate a reduced resolution version of the statewide probability dataset. The cell size of the dataset was multiplied by 3 in order to create a 90-meter by 90-meter grid from the original 30-meter by 30-meter grid. The output value for each cell in the resulting dataset represents the mean of the input cells that the coarser output cells encompass. The resolution of the dataset was reduced in order to keep the dataset resolution consistent with the input explanatory dataset having the lowest resolution, which was the soils dataset with a cell size of 100 meters. Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: The proportions of the statewide probability dataset were altered by resampling the dataset. The "resample" tool within the Data Management raster toolbox was used to change the cell size of the dataset from 90 meters to 100 meters in order to correspond with the 100-meter accuracy of the average soil available water capacity dataset. Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: The dataset was projected using the Project Raster tool within the Data Management Projections and Transformations toolbox. The output coordinate system was defined as WGS_1984_Web_Mercator, and the NAD_1983_To_WGS_1984_5 and WGS_1984_Major_Auxiliary_Sphere_To_WGS_1984 geographic transformations were used. The nearest neighbor assignment resampling technique was applied during this process in order to preserve the original cell values. The dataset was required to be projected since the PA EPHT program data portal and other ArcGIS applications being developed within the state of Pennsylvania will be using ESRI ArcGIS online web mapping services. Therefore the resulting dataset must match the coordinate system and projection utilized by ESRI. Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: Metadata were created. Process_Date: 2012 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Eliza L. Gross Contact_Organization: U.S. Geological Survey Pennsylvania Water Science Center Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: Pennsylvania Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Hours_of_Service: M - F, 8:00 am - 4:30 pm Process_Step: Process_Description: Metadata imported. Source_Used_Citation_Abbreviation: C:\Users\egross\AppData\Local\Temp\2\xmlF8D8.tmp Process_Date: 20101207 Process_Time: 15182200 Cloud_Cover: Not Applicable Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 3852 Column_Count: 6681 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Mercator Mercator: Standard_Parallel: 0.000000 Longitude_of_Central_Meridian: 0.000000 False_Easting: 0.000000 False_Northing: 0.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: row and column Coordinate_Representation: Abscissa_Resolution: 100.000000 Ordinate_Resolution: 100.000000 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: D_User_Defined Ellipsoid_Name: User_Defined_Spheroid Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: infinity Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: VALUE Entity_Type_Definition: prob_as4_pa is a continuous floating point raster grid representing the predicted probabilities of arsenic occurring at 4 micrograms per liter or greater in the groundwater. The values range from 0 to 100. Entity_Type_Definition_Source: SIR 2012-5257 Attribute: Attribute_Definition: prob_as4_pa is a continuous floating point raster grid representing the predicted probabilities of arsenic occurring at 4 micrograms per liter or greater in the groundwater. The values range from 0 to 100. Attribute_Definition_Source: SIR 2012-5257 Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: VALUE Enumerated_Domain_Value_Definition: prob_as4_pa is a continuous floating point raster grid representing the predicted probabilities of arsenic occurring at 4 micrograms per liter or greater in the groundwater. The values range from 0 to 100. Enumerated_Domain_Value_Definition_Source: SIR 2012-5257 Attribute_Value_Accuracy_Information: Attribute_Value_Accuracy: As coded Attribute_Value_Accuracy_Explanation: As coded Attribute_Measurement_Frequency: None planned Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing and physical address Address: 12201 Sunrise Valley Drive City: Reston State_or_Province: VA Postal_Code: 20192 Contact_Voice_Telephone: (800) 426-9000 Resource_Description: Downloadable Data Distribution_Liability: Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Transfer_Size: 105.539 Technical_Prerequisites: This dataset can be used by Geographic Information System (GIS) or image-processing software. Metadata_Reference_Information: Metadata_Date: 20121208 Metadata_Review_Date: February 1, 2013 Metadata_Future_Review_Date: None planned Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pennsylvania Water Science Center Contact_Person: Eliza L. Gross Contact_Position: Physical Scientist Contact_Address: Address_Type: mailing and physical address Address: 215 Limekiln Road City: New Cumberland State_or_Province: PA Postal_Code: 17070 Country: USA Contact_Voice_Telephone: 717-730-6973 Contact_Facsimile_Telephone: 717-730-6997 Contact_Electronic_Mail_Address: egross@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile