Ralph Seiler - Academia.edu (original) (raw)

Papers by Ralph Seiler

Scientific Investigations Report, 2004

Scientific Investigations Report, 2009

Science of The Total Environment, 2016

Scientific Investigations Report, 2004

Scientific Investigations Report, 2004

Circular, 1999

Introduction 1 Background 1 Purpose and scope 2 Acknowledgments 2 Sources of selenium 2 Study met... more Introduction 1 Background 1 Purpose and scope 2 Acknowledgments 2 Sources of selenium 2 Study methods 5 Physical classification of areas 7 Geology 7 Climate 7 Hydrology 11 Classification of study areas by selenium concentrations 12 Water 12 Biota 12 Use of geographic information system to create maps 14 Geologic data layers 14 Climatologic data layers 15 Land-use data layers 16 Factors affecting selenium concentrations in water 16 Geology 16 Climate 18 Hydrology 18 Deformities in aquatic birds and selenium concentrations in bird eggs 20 Map identifying areas susceptible to selenium contamination 21 Assessing map reliability 21 Test areas 21 Correctness of analysis 25 Accuracy and precision of maps 27 Land use within susceptible areas 28 Discussion and summary 28 References cited 32

Open-File Report, 2002

SAR 18. NUMBER OF PAGES 216 19a. NAME OF RESPONSIBLE PERSON

Science of The Total Environment, 2006

Many owners of domestic wells shock chlorinate their wells to treat for bacterial contamination o... more Many owners of domestic wells shock chlorinate their wells to treat for bacterial contamination or control bad odors from sulfides. Analysis of well water with four wells from Fallon, Nevada, showed that following recommended procedures for shock chlorinating wells can cause large, short-lasting increases in trace-element concentrations in ground water, particularly for Cu, Fe, Pb, and Zn. Lead concentrations increased up to 745 fold between samples collected just before the well was shock chlorinated and the first sample collected 22-24 h later; Zn concentrations increased up to 252 fold, Fe concentrations increased up to 114 fold, and Cu concentrations increased up to 29 fold. Lead concentrations returned to near background levels following pumping of about one casing volume, however, in one well an estimated 120 mg of excess Pb were pumped before concentrations returned to prechlorination levels. Total Pb concentrations were much greater than filtered (0.45 microm) concentrations, indicating the excess Pb is principally particulate. Recommended procedures for purging treated wells following shock chlorination may be ineffective because a strong NaOCl solution can remain in the casing above the pump even following extended pumping. Only small changes in gross alpha and beta radioactivity occurred following shock chlorination. USEPA has not promulgated drinking-water standards for 210Pb, however, measured 210Pb activities in the study area typically were less than the Canadian Maximum Acceptable Concentration of 100 mBq/L. By consuming well water shortly after shock chlorination the public may inadvertently be exposed to levels of Pb, and possibly 210Pb, that exceed drinking-water standards.

Science of The Total Environment, 2008

It is well known to the public in Lahontan Valley in rural Nevada, USA, that local aquifers produ... more It is well known to the public in Lahontan Valley in rural Nevada, USA, that local aquifers produce water with varied, but sometimes very high concentrations of arsenic (>4 ppm). As a result, many residents of the area have installed household reverse-osmosis (RO) systems to produce drinking water. We examined performance of RO systems and factors associated with arsenic removal efficiency in 59 households in Lahontan Valley. The sampling results indicated that RO systems removed an average of 80.2% of arsenic from well water. In 18 of the 59 households, arsenic concentrations exceeded 10 ppb in treated water, with a maximum in treated water of 180 ppb. In 3 of the 59 households, RO treatment had little effect on specific conductance, indicating that the RO system was not working properly. Two main factors lead to arsenic levels in treated water exceeding drinking-water standards in the study area. First, arsenic concentrations were high enough in some Lahontan Valley wells that arsenic levels exceeded 10 ppb even though RO treatment removed more than 95% of the arsenic. Second, trivalent As(+3) was the dominant arsenic species in approximately 15% of the wells, which significantly reduced treatment efficiency. Measurements of specific conductance indicated that efficiency in reducing arsenic levels did not always correlate with reductions in total dissolved solids. As a consequence, improvements in taste of the water or simple measurements of specific conductance made by technicians to test RO systems can mislead the public into assuming the water meets safety standards. Actual measurements of treated water are necessary to assure that household RO systems are reducing arsenic concentrations to safe levels, particularly in areas where groundwater has high arsenic concentrations or where As(+3) is the dominant species.

Scientific Investigations Report, 2004

Scientific Investigations Report, 2009

Science of The Total Environment, 2016

Scientific Investigations Report, 2004

Scientific Investigations Report, 2004

Circular, 1999

Introduction 1 Background 1 Purpose and scope 2 Acknowledgments 2 Sources of selenium 2 Study met... more Introduction 1 Background 1 Purpose and scope 2 Acknowledgments 2 Sources of selenium 2 Study methods 5 Physical classification of areas 7 Geology 7 Climate 7 Hydrology 11 Classification of study areas by selenium concentrations 12 Water 12 Biota 12 Use of geographic information system to create maps 14 Geologic data layers 14 Climatologic data layers 15 Land-use data layers 16 Factors affecting selenium concentrations in water 16 Geology 16 Climate 18 Hydrology 18 Deformities in aquatic birds and selenium concentrations in bird eggs 20 Map identifying areas susceptible to selenium contamination 21 Assessing map reliability 21 Test areas 21 Correctness of analysis 25 Accuracy and precision of maps 27 Land use within susceptible areas 28 Discussion and summary 28 References cited 32

Open-File Report, 2002

SAR 18. NUMBER OF PAGES 216 19a. NAME OF RESPONSIBLE PERSON

Science of The Total Environment, 2006

Many owners of domestic wells shock chlorinate their wells to treat for bacterial contamination o... more Many owners of domestic wells shock chlorinate their wells to treat for bacterial contamination or control bad odors from sulfides. Analysis of well water with four wells from Fallon, Nevada, showed that following recommended procedures for shock chlorinating wells can cause large, short-lasting increases in trace-element concentrations in ground water, particularly for Cu, Fe, Pb, and Zn. Lead concentrations increased up to 745 fold between samples collected just before the well was shock chlorinated and the first sample collected 22-24 h later; Zn concentrations increased up to 252 fold, Fe concentrations increased up to 114 fold, and Cu concentrations increased up to 29 fold. Lead concentrations returned to near background levels following pumping of about one casing volume, however, in one well an estimated 120 mg of excess Pb were pumped before concentrations returned to prechlorination levels. Total Pb concentrations were much greater than filtered (0.45 microm) concentrations, indicating the excess Pb is principally particulate. Recommended procedures for purging treated wells following shock chlorination may be ineffective because a strong NaOCl solution can remain in the casing above the pump even following extended pumping. Only small changes in gross alpha and beta radioactivity occurred following shock chlorination. USEPA has not promulgated drinking-water standards for 210Pb, however, measured 210Pb activities in the study area typically were less than the Canadian Maximum Acceptable Concentration of 100 mBq/L. By consuming well water shortly after shock chlorination the public may inadvertently be exposed to levels of Pb, and possibly 210Pb, that exceed drinking-water standards.

Science of The Total Environment, 2008

It is well known to the public in Lahontan Valley in rural Nevada, USA, that local aquifers produ... more It is well known to the public in Lahontan Valley in rural Nevada, USA, that local aquifers produce water with varied, but sometimes very high concentrations of arsenic (>4 ppm). As a result, many residents of the area have installed household reverse-osmosis (RO) systems to produce drinking water. We examined performance of RO systems and factors associated with arsenic removal efficiency in 59 households in Lahontan Valley. The sampling results indicated that RO systems removed an average of 80.2% of arsenic from well water. In 18 of the 59 households, arsenic concentrations exceeded 10 ppb in treated water, with a maximum in treated water of 180 ppb. In 3 of the 59 households, RO treatment had little effect on specific conductance, indicating that the RO system was not working properly. Two main factors lead to arsenic levels in treated water exceeding drinking-water standards in the study area. First, arsenic concentrations were high enough in some Lahontan Valley wells that arsenic levels exceeded 10 ppb even though RO treatment removed more than 95% of the arsenic. Second, trivalent As(+3) was the dominant arsenic species in approximately 15% of the wells, which significantly reduced treatment efficiency. Measurements of specific conductance indicated that efficiency in reducing arsenic levels did not always correlate with reductions in total dissolved solids. As a consequence, improvements in taste of the water or simple measurements of specific conductance made by technicians to test RO systems can mislead the public into assuming the water meets safety standards. Actual measurements of treated water are necessary to assure that household RO systems are reducing arsenic concentrations to safe levels, particularly in areas where groundwater has high arsenic concentrations or where As(+3) is the dominant species.