Table 1. Concentrations of selected organochlorine compounds in two Clear Creek sediment cores

[See text for additional compounds not detected; cm, centimeters; µg/kg, micrograms per kilogram; E, estimated; <, less than; TEC, threshold effect concentration (MacDonald and others, 2000); --, not applicable; PEC, probable effect concentration (MacDonald and others, 2000)

Core
interval
(cm)

Estimated
date of
deposition

Chlor-
dane
(
µg/kg)

DDE
(
µg/kg)

DDD
(
µg/kg)

Dieldrin
(
µg/kg)

Total
PCB
(
µg/kg)

Organic
carbon
(percent)

CCA

 

 

 

 

 

 

 

0–5

2001

E5.4  

E.4  

<1.0

<1.0

E6.6

1.5

10–15

1998

E3.5  

<1.5  

<1.5

<1.5

E3.1

1.5

20–25

1996

E2.2  

E.3  

<0.5

<.5

E3.5

1.3

30–35

1993

<10     

E.5  

<1.0

<1.0

E6.5

1.2

40–45

1990

<5.0  

E.4  

<.5

<.5

E6.0

1.3

50–55

 

1987

<15    

E1.2  

<1.5

<1.5

E24

1.3

65–70

1982

<5.0  

E.5  

<.5

<.5

E8.9

1.3

80–85

1977

<5.0  

1.8  

<.5

<.5

E12  

1.4

95–100

1971

<5.0  

2.9  

<.5

<.5

E19  

1.4

110–115

1966

<10    

7.2  

<1.0

<1.0

E36  

1.6

125–130

 

1960

<10     

6.2 

<1.0

<1.0

E67 

2.3

CCD

 

 

 

 

 

 

 

0–4

2001

E8.3 

<1.5  

<1.5

<1.5

<45  

1.3

8–12

1999

<20    

E1.0  

<2.0

<2.0

E29  

1.2

16–20

1995

<5.0  

E.3  

<.5

<.5

E4.9

1.1

24–28

1992

<15    

E.3  

<1.5

<1.5

E11 

1.0

32–36

 

1988

<10    

E.3  

<1.0

<1.0

E11  

1.1

40–44

1984

<5.0  

<.50

<.5

<.5

E9.0

1.0

52–56

1979

<5.0  

<.50

<.5

<.5

<15  

1.2

64–68

1973

<5.0  

1.6  

1.0

<.5

31 

1.2

76–80

1968

<5.0  

4.8  

<.5

.7

114  

1.2

88–92

 

1962

<10     

2.1  

E.4

<1.0

<30  

1.0

TEC

--

3.24

3.16

4.88

1.9

59.8

--

PEC

--

17.6

31   

28.0

61.8

676  

--

 

Back to Text | Contents