SUMMARY OF COMPOUND DETECTIONS AND CONCENTRATIONS
Organochlorine Compounds and Trace Elements
Concentrations of semivolatile organic compounds, organochlorine compounds, and trace elements detected in fish and clam tissue and bed sediment of the Trinity River Basin Study Unit.
[µg/kg, micrograms per kilogram; --, not measured; %, percent; µg/g, micrograms per gram; trade names may vary]
| EXPLANATION
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| Organochlorine compound (Trade name) |
Rate of detectionb
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Concentration, in mg/kg 
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| Aldrin (HHDN, Octalene) |
3% 0% |
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total Chlordane |
60% 20% |
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| DCPA (dacthal, chlorthal-dimethyl) |
3% 0% |
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| p,p’-DDE |
61% 49% |
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| total DDT |
67% 49% |
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| Dieldrin (Panoram D-31, Octalox) |
42% 18% |
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| gamma-HCH (lindane, gamma-BHC) |
11% 0% |
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| Heptachlor epoxide |
14% 2% |
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| Heptachlor (heptachlore, Velsicol 104) |
3% 0% |
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| Mirex (Dechlorane) |
0% 2% |
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| PCB, total |
28% 4% |
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| Pentachloroanisole |
8% 0% |
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| Toxaphene (camphechlor, Hercules) |
3% 0% |
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| Trace element | Rate of detectionb | Concentration, in mg/g 
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| Arsenic |
73% 100% |
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| Cadmium |
73% 98% |
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| Chromium |
93% 100% |
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| Copper |
100% 100% |
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| Lead |
67% 100% |
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| Mercury |
67% 67% |
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| Nickel |
73% 100% |
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| Selenium |
100% 100% |
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| Zinc |
100% 96% |
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a Selected water-quality standards and guidelines (Gilliom and others, in press).
bRates of detection are based on the number of analyses and detections in the Study Unit, not on national data. Rates of detection for herbicides and insecticides were computed by counting only detections equal to or greater than 0.01 m/L to facilitate equal comparisons among compounds, which had widely varying detection limits. For herbicides and insecticides, a detection rate of “<1%” means that all detections are less than 0.01 mg/L, or the detection rate rounds to less than 1%. For other compound groups, all detections were counted and minimum detection limits for most compounds were similar to the lower end of the national ranges shown. Method detection limits for all compounds in these tables are summarized in (Gilliom and others, in press).
cDetections of these compounds are reliable, but concentrations are determined with greater uncertainty than for the other compounds and are reported as estimated values (Zaugg and others, 1995).
dThe guideline for methyl tert-butyl ether is between 20 and 40 mg/L if the tentative cancer classification C is accepted, the lifetime health advisory will be 20 mg/L (Gilliom and others, in press).
eSelected sediment-quality guidelines (Gilliom and others, in press).
