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Last modified
8/11/2009 11:32:57 AM
Creation date
8/10/2009 4:56:06 PM
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UCREFRP
UCREFRP Catalog Number
9343
Author
Greve, A. I., N. E. Spahr, P. C. Van Metre and J. T. Wilson.
Title
Identification of Water-Quality Trends Using Sediment Cores from Dillon Reservoir, Summit County, Colorado.
USFW Year
2001.
USFW - Doc Type
Denver.
Copyright Material
NO
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<br />Reservoir-Water Sampling <br /> <br />Quality-control samples (one replicate and <br />one field blank) were collected during the reservoir- <br />water sampling. Differences in the concentrations <br />for trace elements in the replicate samples were gener- <br />ally within I Ilg/L with the exception of dissolved <br />barium, 3 Ilg/L (28 Ilg/L compared to 31 Ilg/L); <br />dissolved zinc, 41lg/L (29 Ilg/L compared to 33 Ilg/L); <br />total zinc, 10 Ilg/L (40 Ilg/L compared to 30 Ilg/L); and <br />total iron, 20 Ilg/L (50 Ilg/L compared to 30 Ilg/L). <br />Total zinc and total iron are reported <br />to the nearest 10 Ilg/L. RPDs are not presented as <br />they do not realistically reflect variability in data <br />sets that span orders of magnitude and are reported <br />with different numbers of significant figures. No <br />detections of trace elements greater than the minimum <br />laboratory reporting limit were found in the blank <br />sample. Variability and bias as a result of reservoir- <br />water sample collection, processing, and analysis <br />did not substantially affect results presented for <br />this study. <br /> <br />IDENTIFICATION OF WATER-QUALITY <br />TRENDS <br /> <br />Pesticides and Polychlorinated Biphenyls <br />in Reservoir-Sediment Cores <br /> <br />Of the 14 pesticides and 3 PCBs for which <br />the reservoir-core samples were analyzed, only <br />2 pesticides were detected. Low concentrations of <br />DDE and DDD, metabolites of DDT, were found <br />at core depths of 5 cm and below 15 cm in core <br />DLN (table I). These findings are reasonable, espe- <br />cially for the sediment below 15 cm, which corre- <br />sponds to the time period of 1963 through 1977. <br />Use of DDT in the United States peaked in the 1960's <br />and was banned in 1972. Sediment cores taken in a <br />number of other lakes and reservoirs had elevated <br />DDE, DDD, and DDT concentrations in the <br />pre-1970 sediment, followed by a slow decline <br />in younger sediment (Van Metre and Callender, <br />1996; Van Metre and others, 1997; Kalkhoff and <br />Van Metre, 1997). No trend analysis was conducted <br />for DDE and DDD due to the large number of <br />censored values. <br /> <br />Table 1. Presence of dichlorodiphenyldichloroethylene <br />(DOE) and dichlorodiphenyldichloroethane (ODD) in <br />core DLN collected in August 1997 <br /> <br />[em. centimeter; E. estimated value; <. less than; /lglkg. micrograms per <br />kilogram dry weight] <br /> <br />Depth Estimated date DDE DDD <br />(cm) of deposition' (/lg/kg) (/lg/kg) <br />0-2 1995.8 <l <l <br />2---4 1992.9 <1 <l <br />4-6 1989.8 1.2 E1.9 <br />6-8 1986.8 <1 <l <br />8-10 1984.4 <l <l <br />10-12 1982.1 <1 <1 <br />12-14 1979.0 <1 <l <br />14-16 1974.5 l.l E1.7 <br />16-18 1968.9 1.2 E1.9 <br />18-19 1964.0 1.4 E2 <br /> <br />*See explanation in text on page 7. <br /> <br />Polycyclic Aromatic Hydrocarbons in <br />Reservoir-Sediment Cores <br /> <br />PAHs, some of which have carcinogenic and <br />mutagenic properties, are a group of petroleum-related <br />compounds that sorb strongly to sediment. They are <br />produced by the burning of coal, oil, gas, wood, and <br />refuse or from uncombusted sources such as oil and <br />petroleum products. Combustion-derived PAHs (in <br />comparison to noncombustion-derived PAHs) tend to <br />have greater proportions of 4- or 5-ringed compounds <br />than 2- or 3-ringed compounds, greater amounts of <br />fluoranthene than pyrene, and more phenanthrene than <br />anthracene than noncombustion-derived PAHs (Heit <br />and others, 1988). In an effort to detect changes due to <br />urban development, the three ratios described above, <br />total PAHs, and total combustion PAHs were analyzed. <br />Total PAHs is the sum all PAH compounds <br />including parent compounds and isomers except <br />perylene. Perylene is excluded from the sum of total <br />PAHs because it is believed to form in situ and not <br />be a petroleum-related compound (LaFlamme and <br />Hites, 1978). Total combustion PAHs refers to the <br />sum of nine compounds that are most commonly <br />found in combustion emissions regardless of the <br />type of fuel being burned. The compounds summed <br />to produce total combustion PAH concentration are <br />fluoranthene, pyrene, benz(a)anthracene, chrysene, <br />benzofluoranthenes, benzo( a)pyrene, benzo( e )pyrene, <br />indeno( I ,2,3-c,d)pyrene, and benzo(g,h,i)perylene <br />(Prahl and Carpenter, 1983). <br /> <br />10 Identification of Water-Quality Trends Using Sediment Cores from Dillon Reservoir, Summit County, Colorado <br /> <br />
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