Environmental Engineering Reference
In-Depth Information
Table 28
Chlordane concentrations in agricultural soils in the Newport Bay Watershed
0-12 inch Sample Depth
12-24 inch Sample Depth
>24 inch Sample Depth
Range of
Detected
Chlordane
(ppm)
Range of
Detected
Chlordane
(ppm)
Range of
Detected
Chlordane
(ppm)
Total Non-
detect
Samples
Total Non-
detect
Samples
Total Non-
detect
Samples
Detection Limits
(ppm)
Year
Total
Samples
Total Samples
Total Samples
1989
0.240 - 0.240
3
2
--
1
1
0.120 - 0.190
5
3
0.08 or 0.12
1990
0.170 - 0.170
2
1
0.210 - 0.210
1
0
0.190 - 0.190
3
2
0.08 or 0.12
1995
0.047 - 0.055
24
22
0.03
2000
--
28
28
0.05 or 0.50
2002
0.050 - 0.130
174
161
--
27
27
--
2004
--
230
230
--
45
45
0.1 - 10.0
2006
0.077 - 0.160
6
1
--
6
6
0.05
Sources
: Unpublished technical reports provided by The Irvine Company (1985-2006)
Data were not available for shaded areas
60
50
40
30
20
10
0
Date
Lower Newport Bay
Upper Newport Bay
San Diego Creek Watershed
Fig. 25
Chlordane concentrations above method detection limits in sediments from Newport Bay
and Watershed (1997-2011).
Sources
: Masters and Inman (
2000
); SCCWRP BIGHT 98 Survey
(
1998
); Bay and Greenstein (
2003
); Bay et al. (
2004
); unpublished technical reports provided by
The Irvine Company (2000-2004); SARWQCB (
2006
); Orange County Watersheds (2010-2011)
4.1.2
Sediments
Chlordane levels in Bay and Creek sediments are available for lower Newport Bay,
upper Newport Bay, and San Diego Creek for the period 1997 through 2011 (Fig.
25
).
As with DDT, it is diffi cult to infer trends in sediment chlordane concentration over
time from these data for several reasons. First, sampling was conducted by multiple
agencies, using multiple methodologies, at varying locations and sample depths. Given
this diversity in sampling approach and location, direct comparisons among data from
year to year are inappropriate. Second, there is signifi cant movement of sediment into,
Search WWH ::
Custom Search