USGS Open-File Report 01-282 -- Table 6

Open-File Report 01-282

Sediment-Deposition Rates and Organic Compounds in Bottom Sediment at Four Sites in Lake Mead, Nevada, May 1998

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Table 6. Summary of selected synthetic organic compounds, with maximum concentration and depth, in bottom-sediment cores at four sites in Lake Mead, May 1998

[Abbreviations: cm, centimeters; µg/kg, micrograms per kilogram; pg/g, picograms per gram; NA, not analyzed; DDD, dichlorodiphenyldichloroethane; DDE, dichlorodiphenyldichloroethylene; TCDD, tetrachlorodibenzo-p-dioxin; OCDD, octochlorodibenzo-p-dioxin; TCDF, tetrachlorodibenzofuran; OCDF, octochlorodibenzofuran. Symbols: -- , not determined; <, less than; *, estimated (reported when the compound has passed all criteria used to identify its presence and only the concentration is estimated)]

Site	Number of organic compounds detected	Synthetic organic compounds
Site	Number of organic compounds detected	Pesticides and total polychlorinated biphenyls	Maximum concentration (µg/kg)	Depth interval (cm)	Dioxins	Maximum concentration (pg/g)	Depth interval (cm)
Site 1: Las Vegas Bay -- shallow	48	DDD	11	30-45	TCDD	39	5-10
Site 1: Las Vegas Bay -- shallow	48	DDE	25	30-35	OCDD	93	95-100
Site 2: Las Vegas Bay -- deep	57	DDD	38	20-25	TCDD	22	15-20
Site 2: Las Vegas Bay -- deep	57	DDE	57	20-25	OCDD	44	5-10
Site 3: Overton Arm	26	DDD	<1.5	0-5	TCDD	NA	--
Site 3: Overton Arm	26	DDE	1.4	30-35	OCDD	NA	--
Site 4: Colorado and Virgin Rivers confluence (pre-impoundment)	31	DDD	2.0	24-35	TCDD	<.76	3-6
	31	DDE	2.3	18-21	OCDD	<11	3-6

Site	Synthetic organic compounds
Site	Furans	Maximum concentration (pg/g)	Depth interval (cm)	Polycyclic aromatic hydrocarbons	Maximum concentration (µg/kg)	Depth interval (cm)	Phenols	Maximum concentration (g/kg)	Depth interval (cm)
Site 1: Las Vegas Bay -- shallow	TCDF	150	35-40	Benzo[g,h,i]perylene	16.5	30-35	Phenol	*9.8	20-25
	OCDF	110	35-40	2,6-dimethylnaphthalene	81.9	60-65
				Indeno[1,2,3-c,d]pyrene	15.3	30-35
				Perylene	*7.6	10-15
				Pyrene	10.7	10-15
Site 2: Las Vegas Bay -- deep	TCDF	320	15-20	Benzo[g,h,i]perylene	17.4	20-25	Phenol	18.3	80-85
	OCDF	280	25-30	2,6-dimethylnaphthalene	123	60-65
				Indeno[1,2,3-c,d]pyrene	21.2	80-85
				Perylene	11.3	80-85
				Pyrene	8.8	80-85
Site 3: Overton Arm	TCDF	NA	--	Benzo[g,h,i]perylene	*3.4	0-5	Phenol	*8.2	0-5
	OCDF	NA	--	2,6-dimethylnaphthalene	70.7	30-35
				Indeno[1,2,3-c,d]pyrene	*3.5	0-5
				Perylene	197	30-35
				Pyrene	*3.6	10-15
Site 4: Colorado and Virgin Rivers confluence (pre-impoundment)	TCDF	<.89	15-18	Benzo[g,h,i]perylene	*7.6	40-45	Phenol	33	50-55
	OCDF	<4.8	3-6	2,6-dimethylnaphthalene	77.8	18-21
				Indeno[1,2,3-c,d]pyrene	*5.8	40-45
				Perylene	259	75-80
				Pyrene	*5.8	40-45