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Open-File Report 01-282

Sediment-Deposition Rates and Organic Compounds in Bottom Sediment at Four Sites in Lake Mead, Nevada, May 1998

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Table 9. Furan concentrations in bottom-sediment cores at three sites in Lake Mead, May 1998

[Abbreviations: TCDF, tetrachlorodibenzofuran; PeCDF, pentachlorodibenzofuran; HxCDF, hexachlorodibenzofuran; HpCDF, heptachlorodibenzofuran; OCDF, octachlorodibenzofuran. Symbols: <, less than; *, estimated (reported when the compound has passed all criteria used to identify its presence and only the concentration is estimated). All concentrations are in picograms per gram]

Depth interval (centimeters)

Total TCDF

2,3,7,8 TCDF

Total PeCDF

1,2,3,7,8 PeCDF

2,3,4,7,8 PeCDF

Total HxCDF

1,2,3,4,7,8 HxCDF

Site 1: Las Vegas Bay -- shallow

5-10

85

4.5

54

*10

<4.7

46

15

15-20 86 5.3 36 *8.2 <4.1 19 *10
25-30 110 6.1 44 *9.5 <4.5 33 *11
35-40 150 9.0 100 15 *7.5 72 20
55-60 92 5.4 28 *7.9 <3.6 20 *8.4
75-80 32 2.1 7.4 <3.3 <1.2 8.2 *4.1
95-100 48 2.8 49 *8.0 <3.4 48 13

Site 2: Las Vegas Bay -- deep

5-10

97

6.8

64

*12

<5.8

50

17

15-20 320 20 220 27 13 180 41
25-30 260 16 220 25 13 190 42
35-40 85 5.4 62 9.5 *4.5 28 12
55-60 41 3.0 9.7 <3.7 <2.2 <4.3 <4.5
75-80 36 *2.1 17 <3.4 <1.7 <4.4 <4.4
95-100 19 *1.3 <5.2 <1.8 <1.2 <1.8 <1.8

Site 4: Colorado and Virgin Rivers confluence (pre-impoundment)

3-6

<.76

<.76

<1.6

<1.6

<1.6

<.66

<.59

9-12 <.72 <.72 <1.1 <1.1 <1.1 <.65 <.56
15-18 <.89 <.33 <1.5 <1.5 <1.5 <.73 <.58
21-24 <.74 <.74 <2.1 <2.1 <2.1 <.96 <.85
45-50 <.55 <.55 <.60 <.60 <.60 <.69 <.60
65-70 <.64 <.64 <1.5 <1.4 <1.5 <.67 <.58

 

Depth interval (centimeters)

1,2,3,6,7,8 HxCDF

2,3,4,6,7,8 HxCDF

1,2,3,7,8,9 HxCDF

Total HpCDF

1,2,3,4,6,7,8 HpCDF

1,2,3,4,7,8,9 HpCDF

OCDF

Site 1: Las Vegas Bay -- shallow

5-10

*9.2

<2.2

<2.2

60

29

*11

100

15-20 <5.9 <1.7 <1.6 30 16 *6.7 58
25-30 *6.9 <1.5 <1.6 35 19 *8.2 66
35-40 12 <3.3 <2.3 66 31 15 110
55-60 <4.4 <1.5 <1.2 20 13 *6.9 44
75-80 <2.5 <.87 <1.6 8.0 *8.0 <2.8 23
95-100 *8.8 <2.2 <2.1 65 32 11 90

Site 2: Las Vegas Bay -- deep

5-10

*9.6

<2.0

<2.1

60

28

*13

100

15-20 24 *5.9 *4.5 150 72 31 260
25-30 24 *6.4 *4.4 150 69 32 280
35-40 *6.4 <1.4 <1.4 39 19 7.8 67
55-60 <2.9 <.73 <.63 7.6 *7.6 <2.5 23
75-80 <2.7 <1.1 <.80 13 *7.8 <2.8 26
95-100 <1.3 <.38 <.30 <3.8 <3.8 <1.6 *11

Site 4: Colorado and Virgin Rivers confluence (pre-impoundment)

3-6

<.64

<.57

<.66

<1.8

<1.6

<1.8

<4.8

9-12 <.63 <.58 <.65 <.85 <.85 <.43 <.74
15-18 <.63 <.61 <.73 <.65 <.47 <.65 <.89
21-24 <.90 <.79 <.96 <.68 <.68 <.68 <2.4
45-50 <.66 <.58 <.69 <.52 <.38 <.52 <1.5
65-70 <.64 <.55 <.67 <.70 <.46 <.70 <1.3