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U.S. GEOLOGICAL SURVEY
Open-File Report 2005-1178

Sediment Chemistry of the Colorado River Delta of Lake Powell, Utah, 2001

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Prepared in cooperation with the
NATIONAL PARK SERVICE,
GLEN CANYON NATIONAL RECREATION AREA

By R.J. Hart, H.E. Taylor, R.C. Antweiler, D.D. Graham, G.G. Fisk, S.G. Riggins, and M.E. Flynn

ABSTRACT

Sediment delta deposits in Lake Powell provide a repository for the potential accumulation of various natural and human-introduced chemicals. The Colorado River delta of Lake Powell near Hite, Utah, extends for many miles into Lake Powell and is thickest near the mouth of the Dirty Devil River. Other significant deltas in Lake Powell occur at the mouths of the San Juan and Escalante Rivers.

Sediment samples collected from the Colorado River delta during July 2001 were analyzed for concentrations of major ions; trace elements; organic compounds, including low-level organochlorine pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons; and radionuclides. Three cores and six sediment samples from the sediment-water interface were collected near Hite marina in southeastern Utah where the delta is thickest. No trends were discernable between major-ion concentrations in different cores. Concentrations of several trace elements were correlative with sediment color and texture. Elements that are considered to be environmental contaminants, such as arsenic, uranium, selenium, and mercury, were detected in core samples. Some elements increased in concentration with core depth. Organochlorine pesticides and polychlorinated biphenyls were not detected in composited sections of the cores above the laboratory detection limit except for p,p’-DDE. A total of 19 parent polycyclic aromatic hydrocarbons and multiple alkyl-polycyclic aromatic hydrocarbons were detected in core samples. All core samples contained concentrations of gross alpha and gross beta radionuclides; concentrations in composited samples ranged from 11 to 17 picocuries per gram.

CONTENTS

Abstract
Introduction
Methods
Quality of Data
Sediment Chemistry, Water Chemistry, and Particle-Size Distribution
Considerations for Future Studies
Summary
References Cited
Basic Data

Tables 5 through 13 available in Excel format:

Table 5. Results of standard reference material analyses and associated analytical errors, Colorado River delta, Lake Powell, Utah, 2001

Table 6. Summary of results of standard reference material analyses, Colorado River delta, Lake Powell, Utah, 2001

Table 7. Concentrations of major and trace elements in sediment from the sediment-water interface samples, Colorado River delta, Lake Powell, Utah, 2001

Table 8 . Concentrations of major and trace elements in sediment from the sediment-water interface samples, Colorado River delta, Lake Powell, Utah, 2001

Table 9. Concentrations of low-level organchloride pesticides and polychlorinated biphenols (PCBs) in composited core sections, Colorado River delta, Lake Powell, Utah, 2001

Table 10. Concentrations of polycyclic aromatic hydrocarbons (PAHS) in composited core sections, Colorado River delta, Lake Powell, Utah, 2001

Table 11. Concentrations of radionuclides in composited core sections, Colorado River delta, Lake Powell, Utah, 2001

Table 12. Sediment particle-size distribution in composited core sections, Colorado River delta, Lake Powell, Utah, 2001

Table 13. Concentrations of major and trace elements for samples from sediment-water interface and pore waters, Colorado River delta, Lake Powell, Utah, 2001



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