SUMMARY OF COMPOUND DETECTIONS AND CONCENTRATIONS

EXPLANATION

	Guideline for the protection of aquatic life¹ Range of detections in fish tissue in all 20 NAWQA Study Units Range of detections in bed sediment in all 20 NAWQA Study Units Detection in bed sediment or fish tissue in the Red River of the North Study Unit

Semivolatile organic compound	Rate of detection²	Concentration, in µg/Kg
1,2-Dimethylnaphthalene	-- 14%
1,6-Dimethylnaphthalene	-- 22%
1-Methyl-9H-fluorene	-- 14%
1-Methyl-phenanthrene	-- 31%
1-Methylpyrene	-- 33%
2,2-Biquinoline	-- 6%
2,3,6-Trimethylnaphthalene	-- 14%
2,6-Dimethylnaphthalene	-- 47%
2-Ethylnaphthalene	-- 19%
2-Methylanthracene	-- 22%
3,5-Dimethyl-phenol	-- 6%
4,5-Methylene-phenanthrene	-- 25%
4-Chloro-3-methylphenol	-- 3%
9H-Carbazole	-- 44%
9H-Fluorene	-- 44%
Acenaphthene	-- 22%
Acenaphthylene	-- 22%
Acridine	-- 6%
Anthracene	-- 47%
Anthraquinone	-- 42%
Benz[ a ]anthracene	-- 42%
Benzo[ a ]pyrene	-- 42%
Benzo[ b ]fluoranthene	-- 61%
Benzo[ ghi ]perylene	-- 17%
Benzo[ k ]fluoranthene	-- 64%
Butylbenzyl-phthalate	-- 83%
Chrysene	-- 53%
Di- n -butylphthalate	-- 97%
Di- n -octylphthalate	-- 17%
Dibenz[ a,h ]anthracene	-- 14%
Dibenzothiophene	-- 28%
Diethylphthalate	-- 81%
Dimethyl-phthalate	-- 6%
Fluoranthene	-- 83%
Indeno[1,2,3cd ]pyrene	-- 39%
Isoquinoline	-- 3%
Naphthalene	-- 8%
N-Nitrosodiphenylamine	-- 3%
Phenanthrene	-- 53%
Phenanthridine	-- 6%
Phenol	-- 81%
Pyrene	-- 86%
Quinoline	-- 3%
bis(2-Ethylhexyl)phthalate	-- 92%
p-Cresol	-- 64%
Organochlorine compound	Rate of detection²	Concentration, in µg/kg
total Chlordane	9% 0%
p,p'-DDE	73% 19%
total-DDT	73% 22%
PCB, total	36% 0%
Trace element	Rate of detection²	Concentration, in µg/g
Arsenic	62% 100%
Cadmium	62% 98%
Chromium	62% 100%
Copper	100% 100%
Lead	13% 100%
Mercury	86% 88%
Nickel	13% 100%
Selenium	100% 100%
Zinc	100% 100%

² Rates 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 only counting detections equal to or greater than 0.01 µg/L in order 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 µg/L, or the detection rate rounds to less than one percent. 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).

³ Detections 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).

U.S. Geological Survey Circular 1169

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