DDT, Chlordane, Toxaphene and PCB Residues in Newport Bay and Watershed: Assessment of Hazard to Wildlife and Human Health - Reviews of Environmental Contamination and Toxicology - page 139

400

350

300

250

200

150

100

50

0

Jan-1980 Jan-1985 Jan-1990 Jan-1995 Jan-2000 Jan-2005

Date

y = 7E+06e -0.0003x
R 2 = 0.2611

y = 1E+08e -0.0004x
R 2 = 0.7101

y = 2E+07e -0.0004x
R 2 = 0.3975

Red Shiner (1983-1991) Red Shiner (1992-2000) Red Shiner (1983-2000)

Expon. (Red Shiner (1983-1991)) Expon. (Red Shiner (1992-2000)) Expon. (Red Shiner (1983-2000))

Fig. 26 Chlordane concentrations in red shiner, San Diego Creek and Peters Canyon Wash
(1983-2000). Data from California Toxic Substances Monitoring Program ( 1983 -2000). Red
shiner data from 2002 to the present are not available

100

90

80

70

60

50

40

30

20

10

0

Jan-1992 Jan-1995 Jan-1998 Jan-2001 Jan-2004 Jan-2007 Jan-2010

Date

Red Shiner (1983-2000) Expon. (Red Shiner (1983-2000))

Fig. 27 Chlordane concentrations in red shiner in San Diego Creek and Peters Canyon Wash
projected through 2010. Data from California Toxic Substances Monitoring Program ( 1983 -2000).
Red shiner data from 2002 to the present are not available

both periods. Therefore, the downward trend observed in the complete data set
(1983-2000) is not simply the result of a temporally localized effect, but rather is an
accurate portrayal of declines in chlordane concentrations over the entire period.
The decay rate (−0.00046 per day or −0.17 per year) obtained for the full red shiner
data set (1983-2000) is equivalent to a half-life of 4.1 years.