USGS

Open-File Report 93-360

Organic Contaminants Associated with Suspended Sediment Collected During Five Cruises of the Mississippi River and its Principal Tributaries, May 1988 to June 1990

By Colleen E. Rostad, LaDonna M. Bishop, Geoffrey S. Ellis, Thomas J. Leiker, Stephanie G. Monsterleet, and Wilfred E. Pereira

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Table of Contents

Abstract

Introduction

Methods

Organic Contaminant Data

Literature Cited

Figures

Figure 1. Location of sampling sites on the Mississippi River and its princ...

Tables

Table 1. Cross-section sampling sites during cruises of May-June 1988, Marc...

Table 2. Mississippi River suspended-sediment concentration (smaller than 6...

Table 3. Instrumental analytical detection limit for 1 microliter of standa...

Table 4. Percent recovery for triplicate samples spiked at 20 nanograms of ...

Table 5. Halogenated organic compounds found in suspended-sediment samples ...

Table 6. Halogenated organic compounds found in suspended-sediment samples ...

Table 7. Halogenated organic compounds found in suspended-sediment samples ...

Table 8. Halogenated organic compounds found in suspended-sediment samples ...

Table 9. Halogenated organic compounds found in suspended-sediment samples ...

Table 10. Average relative standard deviation, in percent, for replicate an...

Table 11. Halogenated organic compounds in suspended-sediment depth-integra...

Table 12. Hydrophobic U.S. Environmental Protection Agency priority polluta...

Table 13. Hydrophobic U.S. Environmental Protection Agency priority polluta...

Table 14. Semiquantitative screening for organochlorine compounds and herbi...

Table 15. Semiquantitative screening for organochlorine compounds and herbi...


Abstract

Suspended-sediment samples were obtained from sites along the Mississippi River and its principal tributaries to determine the presence of halogenated hydrophobic organic compounds on the suspended sediment smaller than 63 micrometers. Sample collection involved pumping discharge-weighted volumes of river water along a cross section of the river into a continuous-flow centrifuge to isolate the suspended sediment. The suspended sediment was analyzed by gas chromatography/mass spectrometry for pentachlorobenzene, hexachlorobenzene, pentachloroanisole, chlorothalonil, pentachlorophenol, dachthal, chlordane, nonachlor, and penta-, hexa-, hepta-, and octachlorobiphenyls. Samples collected during June 1989 and February-March 1990 also were analyzed for U.S. Environmental Protection Agency priority pollutants, including polycyclic aromatic hydrocarbons, phthalate esters, and triazines. Samples were collected at sites on the Mississippi River from above St. Louis, Missouri to below New Orleans, Louisiana, and on the Illinois, Missouri, Ohio, Wabash, Cumberland, Tennessee, White, Arkansas, and Yazoo Rivers. Masses of selected halogenated hydrophobic organic compounds associated with the suspended sediment at each site are presented in this report in tabular format, along with suspended-sediment concentration, water discharge, and organic-carbon content.

Introduction

The Mississippi River is the major river of North America, draining 2.97 million square kilometers, or 40 percent of the contiguous United States, and parts of two provinces in Canada. It is an important resource for food, transportation, drinking water, recreation, and irrigation. The sediment load of the Mississippi River has decreased substantially over the last 50 years, mostly because of the extensive series of dams built on its tributaries (Meade and Parker, 1985; Keown and others, 1986; Meade and others, 1990).

There have been few studies of the organic compounds associated with suspended sediment. One study on sites in Louisiana reported that almost all compounds were below detection limits of 1 ng/g (Demas and Curwick, 1987; 1988). Suspended-sediment studies on other rivers also reported target compounds to be present below the detection limit of 4 ng/g (Merriman, 1988). Distribution of the organic compounds on the suspended sediment in the entire lower Mississippi River from above St. Louis, Missouri to below New Orleans, Louisiana, however, has not been previously addressed. Consequently, an assessment of the occurrence and distribution of organic contaminants is needed to provide a basis for evaluating contaminant transport associated with the suspended sediment.

Four interactive factors that have substantially affected the suspended-sediment regime over this same period of time include increases in: (1) agriculture; (2) commerce and industry; (3) transportation networks; and (4) population and urbanization (Keown and others, 1981). Industrial discharge and nonpoint-source agricultural runoff have increased the loads of anthropogenic organic compounds in the river. Some of these compounds remain in the aqueous phase and have been investigated throughout the river (Schafer and others, 1969; DeLeon and others, 1986; Pereira and Rostad, 1990). Some of the less-soluble compounds adsorb onto bed sediments and also have been investigated (Barthel and others, 1969; Lytle and Lytle, 1990). Most previous studies have focused only on the transport and deposition of the suspended sediment itself (Everett, 1971; Robbins, 1976; Wells, 1980; Meade and Parker, 1985; Grayman, 1985; Meade and others, 1990).

Suspended-sediment composition is affected by surface-soil runoff and by deposition and resuspension, which are dependent upon the ever-changing flow dynamics of the river. A comprehensive compilation of environmental characteristics and history of suspended sediment in the Mississippi River was provided by Keown and others (1981). Annually, the Ohio River contributes about 50 percent of the water but only about 37 percent of the sediment in the Mississippi River. In contrast, about 15 percent of the water and at least 40 percent of the sediment in the Mississippi River are contributed by the Missouri River (Moody and Meade, 1992). The Missouri River mainly drains agricultural areas; the Ohio River drains more industrial areas. Physical differences in suspended sediment and differences in chemical inputs from these two major tributaries may affect the distribution of organic compounds on the suspended sediment in the Mississippi River.

The Mississippi River Study of the U.S. Geological Survey is a multidisciplinary project to quantify environmental facets of an active river system, such as water and sediment transport, tributary mixing, and water quality. Specific aspects for study included trace metals, nutrients, pesticides, fecal sterols, surfactants, and halogenated organic compounds. The objectives of the portion of the study focusing on halogenated organic compounds included:

  1. To procure large enough suspended-sediment sample (smaller than 63 micron) to enable detection of target organic compounds.
  2. To extract suspended sediment in order to isolate target organic compounds.
  3. To utilize sensitive, specific gas chromatography/negative chemical ionization/mass spectrometry to compensate for complex matrix effects in the analysis for the target organic compounds.
  4. To determine the occurrence and distribution of halogenated organic compounds on the suspended sediment in the Mississippi River.

The variety of organic compounds and the trace levels present associated with the suspended sediment necessitate large sample sizes (hundreds of liters) to provide sufficient sample for analysis. Representative suspended sediment in suitable quantities for analysis of trace toxic organic compounds is much more difficult to obtain than the readily available bed sediments. In order to determine transport of organic contaminants on the suspended sediment in the Mississippi River, representative samples at selected sites were combined with information on the water discharge measured at each site.

Purpose and Scope

The purpose of this report is to describe the distribution of halogenated anthropogenic and U.S. Environmental Protection Agency (EPA) priority pollutant (Federal Register, 1980) compounds found on the suspended sediment smaller than 63 micron at selected sites on the Mississippi River for five cruises over a 2-year period, from May 1988 to June 1990.

Suspended sediment was obtained from sites along the Mississippi River and its principal tributaries as part of an ongoing, multidisciplinary study by the U.S. Geological Survey (USGS) (Leenheer and others, 1989; Meade and Stevens, 1990; Pereira and others, 1990; Rees and Ranville, 1990; Taylor and others, 1990). Five sampling cruises during May-June 1988, March-April 1989, June 1989, February-March 1990, and May-June 1990 included a variety of flow conditions. The sampling cruises on the Mississippi River covered over 1,700 km. Sampling locations included sites on the mainstem of the Mississippi River, as well as on the Illinois, Missouri, Ohio, White, Arkansas, and Yazoo Rivers.

The entire Midwest was in a severe drought during the sampling cruise in May-June 1988. For May and June 1988, total flow at the 181 USGS stream index stations in the conterminous United States and southern Canada was the lowest recorded for May and June in the previous 6 years (U.S. Geological Survey, and Canada, Department of the Environment, 1988a and 1988b). The later cruises in 1989 and 1990 were planned to sample the Mississippi River at high water. Detailed hydrologic conditions are given by Moody and Meade (1992 and 1993) for all cruises in this report.

Suspended sediment was collected and analyzed for organic compounds. The analytical protocol was chosen to focus on halogenated hydrophobic anthropogenic organic compounds. By combining large sample sizes with specialized analytical techniques, lower detection limits than those previously mentioned were achieved in this study. The use of highly specific, very sensitive gas chromatography/negative chemical ionization/mass spectrometry enabled a detection limit of 0.05 ng/g for most compounds in spite of the complex sample matrix. The compounds included pentachlorobenzene (present in hexachlorobenzene formulations), hexachlorobenzene (fungicide), pentachloroanisole (transformation product of pentachlorophenol), chlorothalonil (fungicide), pentachlorophenol (wood preservative and general herbicide), dachthal (preemergent herbicide), chlordane (insecticide), nonachlor (present in technical chlordane formulations), and penta-, hexa-, hepta-, and octachlorobiphenyls (PCBs, industrial chemicals).

For each cruise, masses of selected halogenated hydrophobic organic compounds were measured on the suspended sediment analyzed from each site. These data are presented in this report in tabular format, along with water discharge, suspended-sediment concentration, and percent organic carbon on the sediment. In addition, EPA priority pollutants were determined in selected samples from the June 1989 and February-March 1990 sampling cruises.

Acknowledgments

Suspended-sediment sampling of this scale requires the dedicated assistance of many individuals, particularly for the field work. The authors thank the following people for providing data and helping collect and process the samples that we analyzed: T. Brinton, P. Brown, J. Garbarino, J. Leenheer, D. Martin, R. Meade, J. Moody, T. Noyes, D. Peart, T. Rees, J. Ranville, J. Seeley, R. Stallard, H. Stevens, H. Taylor, and T. Willoughby. The authors also thank the crew of Research Vessel ACADIANA, owned and operated by Louisiana Universities Marine Consortium: Captains L. Black, C. LeBoeuf, W. Simoneaux, and S. Rabalais, and crewmen W. DeLaune, C. Guidry, D. Lapreyrouse, and R. Cutting.

Methods

Sample collection

Representative, discharge-weighted, suspended-sediment samples were collected during May-June 1988, March-April 1989, June 1989, February-March 1990, and May-June 1990 at various sites along the Mississippi River and its principal tributaries by using techniques described by Moody and Meade (1992 and 1993). The sampling sites for each cruise are shown on figure 1 and listed in table 1.

A Lagrangian sampling scheme (Nordin and others, 1983; Meade and Stevens, 1990) was used that attempted to follow the same parcel of water as it moved down the river channel, as determined by the mean water velocity. The Lagrangian sampling scheme was most successfully attained on the cruises of May-June 1988 and February-March 1990. On the first of these, the Mississippi River velocities were slow enough that tributaries could be sampled without interrupting the Lagrangian continuity; the second cruise was specifically designed to follow the late-winter discharge of the Ohio River from Uniontown, Ky., to Belle Chasse, La., and therefore no tributaries were sampled (Moody, 1993; Moody and Meade, 1993).

Two types of suspended-sediment samples were collected: depth-integrated composite sample (8 to 139 L) and a larger (299 to 916 L) pumped composite sample. Analyses listed in this report are for the pumped composite sample.

The depth-integrated composite samples were collected concurrently with the pumped composite samples, according to procedures described by Meade (1985), Meade and Stevens (1990), and Moody and Meade (1992). The discharge-weighted concentration of suspended sediment finer than 63 micrometers in the river at each site was determined by filtration through paired, preweighed Millipore filters (see Moody and Meade, 1992 and 1993 for details). The concentration of suspended sediment varies with depth. The sample taken for determination of the suspended-sediment concentration, collected concurrently with the pumped samples was discharge-weighted and depth-integrated according to procedures described by Meade (1985), Meade and Stevens (1990), and Moody and Meade (1992 and 1993). As such, this latter sample is more representative of the total suspended-sediment transport in the river than the pumped sample collected for organic analysis and therefore was used to determine the total suspended-sediment concentration. This discharge-weighted concentration of suspended sediment and the discharge as determined by the depth-integration method described by Moody and Troutman (1992) are presented in table 2. Further details of the water-discharge and suspended-sediment measurements are reported by Moody and Meade (1992).

At each sampling cross section, the water discharge was estimated at each of 5-30 equally spaced verticals, using the depth profile of the river and five depth-integrated velocity measurements. A discharge-weighted, pumped sample that was proportional to the estimated fractional discharge at each vertical was collected (Moody, 1993; Moody and Meade, 1993).

The 17-m research vessel from which the samples were collected was positioned in the river at each of as many as 30 verticals in the cross section by using microwave trisponders located on each bank. The discharge-weighted pumped sample was collected at each vertical from one-half the depth or 5 m, whichever was less. The maximum possible sampling depth for the equipment used was 5 m. The water was pumped through FEP Teflon tubing rigidly positioned parallel to the flow by using an air-driven, double-diaphragm Teflon pump, into a 63-micron nickel-mesh sieve. The water then flowed into a large (40 L) glass funnel, which provided constant head pressure into a continuous-flow, high-speed centrifuge (Sharples AS-12). The centrifuge was operated at 16,000 revolutions per minute and is described in detail by Leenheer and others (1989) and Rees and others (1991). To ensure high recovery efficiency of suspended sediment, the 2-L/min flow rate through the centrifuge was one-half that used by Ongley and Blachford (1982), who reported preferential losses of the organic-rich portion over the mineral-rich suspended sediment at 4 L/min. Sediment particles as small as 370 nm were recovered in the centrifuge (Rees and Ranville, 1990).

All exposed centrifuge surfaces were coated with or directly machined from TFA or FEP Teflon to minimize sample contamination. The suspended sediment from a total of 299 to 916 L of water was deposited on the cylindrical wall of the centrifuge bowl, which was lined with a removable sheet of 0.35-mm-thick FEP Teflon. The liner was easily transferred from the bowl, using Teflon tweezers and FEP Teflon gloves, into an FEP Teflon sample bag, where the sediment sample was resuspended by gentle massage of the liner from outside the bag. The suspended sediment from the 299 to 916 L of river water was then contained in 1 to 2 L of water. This solution was transferred to 1-L glass jars, preserved with five drops of chloroform, refrigerated, transported on ice to the laboratory, allowed to settle for at least 1 week, aspirated to remove the supernatant, and air-dried in the original container.

Comparative studies (J.A. Moody and R.H. Meade, U.S. Geological Survey, written commun., 1992) indicated that the size distribution of suspended particles smaller than 63 micrometers in the pumped samples was virtually identical to that in the composite depth-integrated samples; thus, the pumped sample is representative of the fine fraction (smaller than 63 micrometers) of suspended sediment transported by the river.

The organic carbon content in percent (table 2) for the analyzed suspended sediment, was determined by Huffman Laboratories, Golden, Colo. Duplicate samples varied less than 2 percent from the mean. These data enable calculation of loads.


Location of sampling sites

Figure 1. Location of sampling sites on the Mississippi River and its principal tributaries (modified from Moody and Meade, 1992 and 1993).


Table 1. Cross-section sampling sites during cruises of May-June 1988, March-April 1989, June 1989, February-March 1990, and May-June 1990.

[X designates that the cross section was sampled]

Sampling site River mile1 May-June 1988 Mar-April 1989 June 1989 Feb-Mar 1990 May-June 1990
Mississippi River near Winfield, Mo. UM 239.2 X X X            
Illinois River below Meredosia, Ill. IL 67.2 X                        
Illinois River at Valley City, Ill. IL 61.0                         X
Illinois River at Hardin, Ill. IL 21.8       X X            
Mississippi River below Grafton, Ill. UM 214.6                         X
Missouri River at Hermann, Mo. MO 97.9 X X X            
Mississippi River at St. Louis, Mo. UM 179.3 X X X            
Mississippi River at Thebes, Ill. UM 43.9 X X X       X
Mississippi River near Cache, Ill. UM 14.8                   X      
Ohio River at Uniontown, Ky. OH 842.4                   X      
Wabash River near New Haven, Ill. WA 13.8                   X      
Cumberland River near Smithland, Ky. CU 6.8                   X      
Tennessee River near Calvert City, Ky. TE 11.1                   X      
Ohio River at Olmsted, Ill. OH 965.0 X X X X X
Mississippi River below Hickman, Ky. LM 916.8 X X X X      
Mississippi River at Fulton, Tenn. LM 777.3 X       X            
Mississippi River below Fulton, Tenn. LM 773.5       X       X      
Mississippi River below Memphis, Tenn. LM 731.2                         X
Mississippi River at Helena, Ark. LM 663.9 X X X X      
White River at Mile 11.5, Ark. WH 11.5 X X X            
Arkansas River at Pendleton, Ark. AR 22.4       X X            
Mississippi River above Arkansas City, Ark. LM 566.0 X X X X      
Mississippi River below Arkansas City, Ark. LM 551.7                         X
Yazoo River at Mile 10.0, Miss. YZ 10.0 X                        
Yazoo River below Steele Bayou, Miss. YZ 9.0       X X       X
Mississippi River below Vicksburg, Miss. LM 433.4 X X X X X
Old River Outflow Channel near Knox Landing, Ark. OR 5.5 X X X            
Mississippi River near St. Francisville, La. LM 266.4 X X X X X
Mississippi River below Belle Chasse, La. LM 73.1 X X X X X

1UM, Upper Mississippi River miles measured upriver of confluence with Ohio River.

IL, Illinois River miles measured upriver of confluence with Mississippi River (UM 218.0).

MO, Missouri River miles measured upriver of confluence with Mississippi River (UM 195.3).

OH, Ohio River miles measured downriver of Pittsburgh, PA. Ohio-Mississippi River confluence is at Ohio River Mile 981.5 and Lower Mississippi River mile 953.8.

WA, Wabash River miles measured upriver of confluence with Ohio River (OH 848.0).

CU, Cumberland River miles measured upriver of confluence with Ohio River (OH 923.2).

TE, Tennessee River miles measured upriver of confluence with Ohio River (OH 935.5).

LM, Lower Mississippi River miles measured upriver of Head of Passes, La.

WH, White River miles measured upriver of confluence with Mississippi River (LM 598.9).

AR, Arkansas River miles measured upriver of confluence with Mississippi River (LM 581.5).

YZ, Yazoo River miles measured upriver of confluence with Mississippi River (LM 437.2).

OR, Old River Outflow Channel miles measured downriver of the Old River control structure (LM 314.5).


Table 2. Mississippi River suspended-sediment concentration (smaller than 63 micrometer), water discharge, and organic-carbon content.

[mg/L, milligrams per liter; m3/sec, cubic meters per second; Suspended-sediment and discharge data from Moody and Meade, 1992 and 1993]

Date River Sample site Suspended-sediment concentration (mg/L) Water discharge (m3/s) Organic- carbon content (percent)
MAY-JUNE 1988
5-17 Mississippi River near Winfield, Mo. 34 1,700 6.70
5-16 Illinois River below Meredosia, Ill. 58 330 4.28
5-19 Missouri River at Hermann, Mo. 79 1,500 3.38
5-20 Mississippi River at St. Louis, Mo. 66 3,300 3.61
5-22 Mississippi River at Thebes, Ill. 74 3,600 3.81
5-23 Ohio River at Olmsted, Ill. 32 3,200 3.84
5-24 Mississippi River below Hickman, Ky. 60 6,800 3.47
5-26 Mississippi River at Fulton, Tenn. 68 7,200 3.47
5-28 Mississippi River at Helena, Ark. 76 7,100 3.26
5-29 White River at Mile 11.5, Ark. 96 440 2.02
5-30 Mississippi River above Arkansas City, Ark. 87 8,200 3.37
6-01 Yazoo River at Mile 10.0, Miss. 72 70 1.66
6-02 Mississippi River below Vicksburg, Miss. 80 8,000 3.79
6-04 Old River Outflow Channel near Knox Landing, La. 74 2,200 3.00
6-05 Mississippi River near St. Francisville, La. 214 5,700 1.54
6-07 Mississippi River below Belle Chasse, La. 18 5,600 3.74
MARCH-APRIL 1989
3-10 Mississippi River near Winfield, Mo. 23 850 15.42
3-09 Illinois River at Hardin, Ill. 99 410 2.78
3-12 Missouri River at Hermann, Mo. 74 1,480 2.33
3-13 Mississippi River at St. Louis, Mo. 68 3,940 4.57
3-15 Mississippi River at Thebes, Ill. 105 4,890 3.69
3-16 Ohio River at Olmsted, Ill. 152 20,400 2.27
3-17 Mississippi River below Hickman, Ky. 133 24,700 2.47
3-19 Mississippi River below Fulton, Tenn. 138 24,800 2.36
3-21 Mississippi River at Helena, Ark. 133 25,900 2.26
3-22 White River at Mile 11.5, Ark. 44 1,500 1.95
3-23 Arkansas River at Pendleton, Ark. 41 1,900 3.08
3-24 Mississippi River above Arkansas City, Ark. 124 26,800 2.16
3-26 Yazoo River below Steele Bayou, Miss. 150 1,500 1.42
3-27 Mississippi River below Vicksburg, Miss. 122 26,600 2.11
3-29 Old River Outflow Channel near Knox Landing, La. 162 6,160 1.65
3-30 Mississippi River near St. Francisville, La. 116 23,100 2.06
4-01 Mississippi River below Belle Chasse, La. 146 22,500 1.71
JUNE 1989
6-05 Mississippi River near Winfield, Mo. 70 2,320 4.09
6-04 Illinois River at Hardin, Ill. 708 780 2.20
6-07 Missouri River at Hermann, Mo. 472 1,760 2.72
6-08 Mississippi River at St. Louis, Mo. 122 4,760 3.14
6-10 Mississippi River at Thebes, Ill. 117 5,230 3.19
6-11 Ohio River at Olmsted, Ill. 115 8,760 2.46
6-12 Mississippi River below Hickman, Ky. 130 14,100 2.50
6-14 Mississippi River at Fulton, Tenn. 182 15,300 2.11
6-17 Mississippi River at Helena, Ark. 216 16,900 2.03
6-18 White River at Mile 11.5, Ark. 92 770 1.81
6-19 Arkansas River at Pendleton, Ark. 68 3,600 2.64
6-20 Mississippi River above Arkansas City, Ark. 170 23,300 2.14
6-22 Yazoo River below Steele Bayou, Miss. 272 1,070 1.20
6-23 Mississippi River below Vicksburg, Miss. 153 24,800 1.98
6-25 Old River Outflow Channel near Knox Landing, La. 160 4,890 2.18
6-26 Mississippi River near St. Francisville, La. 154 19,000 1.81
6-28 Mississippi River below Belle Chasse, La. 170 20,100 1.72
FEBRUARY-MARCH 1990
2-25 Mississippi River near Cache, Ill. 108 4,240 2.76
3-01 Ohio River at Uniontown, Ky. 204 6,620 2.65
2-28 Wabash River near New Haven, Ill. 148 2,340 2.62
2-23 Cumberland River near Smithland, Ky. 32 2,170 2.35
2-24 Tennessee River near Calvert City, Ky. 48 6,570 1.99
3-03 Ohio River at Olmsted, Ill. 144 16,100 2.41
3-04 Mississippi River below Hickman, Ky. 158 2,100 2.19
3-05 Mississippi River below Fulton, Tenn. 141 22,800 2.12
3-07 Mississippi River at Helena, Ark. 146 23,300 2.43
3-08 Mississippi River above Arkansas City, Ark. 126 33,200 2.11
3-10 Mississippi River below Vicksburg, Miss. 126 34,100 1.95
3-12 Mississippi River near St. Francisville, La. 98 26,300 2.02
3-14 Mississippi River below Belle Chasse, La. 140 26,700 1.75
MAY-JUNE 1990
6-07 Illinois River at Valley City, Ill. 98 1,230 2.98
6-11 Mississippi River below Grafton, Ill. 464 5,040 2.24
6-13 Mississippi River at Thebes, Ill. 1115 12,600 1.83
6-14 Ohio River at Olmsted, Ill. 177 9,550 1.87
6-18 Mississippi River below Memphis, Tenn. 432 20,800 2.06
6-20 Mississippi River below Arkansas City, Ark. 334 25,500 1.92
6-23 Mississippi River below Vicksburg, Miss. 273 27,300 2.00
6-25 Mississippi River near St. Francisville, La. 184 23,200 1.83
6-27 Mississippi River below Belle Chasse, La. 183 23,300 2.03

Sample preparation

Ultra-high-purity distilled-in-glass (Burdick and Jackson GC2) solvents were used. All glassware was baked 8 hours at 340°C prior to use. The suspended sediment (smaller than 63 micrometers) was air-dried at about 23°C, ground in a glass mortar, weighed, and mixed well; a portion was taken for organic-carbon analysis. From the remaining sediment, about 15 g (from the first cruise; larger amounts when possible from later cruises) was weighed into a 150-mL centrifuge bottle and spiked with 10 microliters of 40 ng/microliter 4,4'-dibromooctafluorobiphenyl and 128 ng/microliter of terbuthylazine. The sample was tumbled for 15 minutes to equilibrate the spiked compounds with the sediment. The sample was then extracted twice with 20 mL acetone and once with 5 mL hexane using a sonic probe (Tekmar), pulsed for 3 minutes at 60-percent duty cycle, 40-percent output control, centrifuged at 1,500 revolutions per minute for 10 minutes, and the organic solvent was decanted. The extracts were combined, dried over anhydrous Na2SO4, and concentrated to less than 10 mL in a Kuderna-Danish apparatus. Under a gentle stream of dry N2, the sample extract was reduced to about 0.5 mL. The extract was fractionated either on 3 g of neutral alumina (Bio-Rad AG-7) with 10-mL fractions of (a)hexane; (b)benzene; (c)dichloromethane; (d)1:1 dichloromethane:methanol; and (e)methanol, or on 5 g of 2 percent deactivated florisil with 100-mL fractions of (aa)hexane; (bb)1:1 hexane:ethyl ether; (cc)dichloromethane; (dd)ethyl acetate. The (a) and (b) or (aa), (bb), and (cc) fractions were combined and concentrated to less than 0.5 mL as before. The (d), (e), and (dd) fractions were stored for future analysis. All concentrated extracts were stored in a freezer until analyzed.

Sample analysis

The combined fractions were spiked with injection standards, decafluorobiphenyl and d-10 phenanthrene, and analyzed in triplicate by gas chromatography/negative chemical ionization/mass spectrometry (GC/NCI/MS). The extracts were injected at 280°C on a 30-m, 0.25-mm inside-diameter, 0.25-micron Rtx-5 Restec GC column, at 50oC for 1 minute, ramped to 300°C at 10°C/min and held for 12 minutes. Electron-capture negative chemical ionization was achieved with ultra-high-purity methane reagent gas at 0.30 Torr in the ion source at 100°C, with a filament emission current of 0.25 microamperes and electron energy of 100 electron volts. The Finnigan MAT TSQ-46 mass spectrometer scanned the first quadrupole from 50 to 600 daltons in 1 second, with the electron multiplier at 1,000 volts.

The base peak in the negative molecular-ion cluster of each selected compound was used for quantitation, based on the base peak of the surrogate internal standard, 4,4'-di-bromooctafluorobiphenyl. A six-point calibration curve was generated for each selected compound. Calibration curves for the reference standard solutions ranging up to four orders of magnitude had correlation coefficients ranging from 0.988 to 0.998, and averaged 0.995 for the selected organic compounds. DDT and its degradation products, DDE and DDD, were not quantitated using this protocol because of their low, nonspecific response to NCI.

With time, the instrument loses sensitivity due to contamination of the ion source. Contamination occurs from the chemical ionization, but also from the complex matrix of the samples. The ion volume in the ion source was replaced often to compensate for this problem. Because the response is dependent upon reagent gas pressure, fluctuations in the reagent gas pressure also can cause variations in the data. Because there could be instrumental reasons for variation of the data, especially nondetected values, samples were analyzed at least twice—more if a substantial loss in sensitivity may have occurred.

The instrumental analytical detection limit for the selected hydrophobic, anthropogenic organic compounds per 1-microliter injection of standard solution are shown in table 3 in nanograms. This value represents approximately 0.05 ng/g for penta- and hexachlorobenzene for a 100-microliter extract of a 20-g sample. Higher detection limits exist, especially for pentachlorophenol and chlorthalonil, due to their polarity. The selected compounds were below detection limits in all blanks analyzed.

Because variation in the extent of halogenation causes variations in the NCI response, the polychlorinated biphenyl quantitation was based on a reference standard compound with the same level of chlorination (Erhardt-Zabik and others, 1990). One isomer each of penta-, hexa-, hepta-, and octachlorobiphenyl was arbitrarily chosen as the quantitation reference standard. As discussed in American Society for Testing and Materials Special Technical Publication 976 (Alford-Stevens and Budde, 1988), the magnitude of the inherent error due to this quantitation approach is unknown. No attempt was made to match the isomer distribution pattern to a single technical Arochlor mixture, new or weathered.

Recovery studies require a similar sample matrix devoid of the compounds of interest. Noncontaminated suspended sediment was not available, so a well-mixed composite of excess sediment from several sites was used for recovery studies. An unspiked composite sample and triplicates spiked with the target compounds at 20 ng/g were carried through the entire extraction and analysis. The background levels from the unspiked composite sample were subtracted to produce the percent recovery for the target compounds shown in table 4, along with the percent relative standard deviation for the triplicate extractions. Chlorothalonil recovery was only 1 percent.

Table 3. Instrumental analytical detection limit for 1 microliter of standard solution.

Compound Detection limit, in nanograms
Pentachlorobenzene 0.01
Hexachlorobenzene 0.01
Pentachloroanisole 0.01
Chlorothalonil 1.00
           
Pentachlorophenol 10.00
Dachthal 0.01
Chlordane, cis- + trans- 0.10
Nonachlor, trans- 0.10
           
Pentachlorobiphenyls 0.50
Hexachlorobiphenyls 0.50
Heptachlorobiphenyls 0.05
Octachlorobiphenyls 0.05

Table 4. Percent recovery for triplicate samples spiked at 20 nanograms of target compound per gram suspended sediment.

[RSD = relative standard deviation]

Compound Percent recovery Percent RSD
Pentachlorobenzene 159 11
Hexachlorobenzene 136 13
Pentachloroanisole 168 5
Chlorothalonil 1 66
Pentachlorophenol 102 97
Dachthal 122 25
Chlordane, cis- + trans- 147 17
Nonachlor, trans- 107 11
Pentachlorobiphenyls 207 49
Hexachlorobiphenyls 139 93
Heptachlorobiphenyls 115 35
Octachlorobiphenyls 106 38

Seventeen June 1989 and eight February-March 1990 extracts were reanalyzed for EPA priority pollutants by GC/MS at the U.S. Geological Survey National Water Quality Laboratory in Denver using standard protocol (Wershaw and others, 1983). The sample extracts also were screened semiquantitatively for some organochlorines, triazines, and carbamates. Some of these semiquantitative compounds, such as atrazine, are water soluble and would not be expected to associate with the suspended sediment. Quantitation was based on the internal injection standard, d-10 phenanthrene.

Organic Contaminant Data

The mass in nanograms of each of the selected hydrophobic halogenated compounds in each sample was determined by duplicate or triplicate analysis of the same extract. In tables 5-9, the original sample weight in grams is shown along with the nanograms of target compound from the reported mass of sample. The data are not corrected for recovery. The detection limit in ng/g is dependent on sample size. By reporting the data in mass, the detection limits are the same for all samples. ND indicates the constituent was not detected. Sample sites are listed in downstream order, with the tributaries included. Not all sites were sampled each cruise, as noted in table 1. Further details on sampling sites may be found in reports by Moody and Meade (1992 and 1993).

Table 5. Halogenated organic compounds found in suspended-sediment samples collected during the May-June 1988 cruise.

[ND, not detected; --, no data; masses not corrected for recovery; all masses rounded to two significant figures]

            Mass of compound, in nanograms
            Replicate samples
Sampling site and sample weight Compound A B C Average
Mississippi River near Winfield, Mo. 12-gram sample Pentachlorobenzene 3.6 3.7 -- 3.6
Hexachlorobenzene 5.4 5.5 -- 5.4
Pentachloroanisole 35 32 -- 34
Chlorothalonil 4.3 ND -- 4.3
Pentachlorophenol ND ND -- ND
Dachthal 21 13 -- 17
Chlordane, cis- + trans- 45 50 -- 48
Nonachlor, trans- 14 21 -- 18
Pentachlorobiphenyls 290 380 -- 340
Hexachlorobiphenyls 850 530 -- 690
Heptachlorobiphenyls 66 77 -- 72
Octachlorobiphenyls 14 11 -- 12
     
Illinois River below Meredosia, Ill., 15-gram sample Pentachlorobenzene 5.8 3.5 -- 4.6
Hexachlorobenzene 6.5 6.3 -- 6.4
Pentachloroanisole 14 14 -- 14
Chlorothalonil 2.2 ND -- 2.2
Pentachlorophenol ND ND -- ND
Dachthal 17 15 -- 16
Chlordane, cis- + trans- 160 180 -- 170
Nonachlor, trans- 40 41 -- 40
Pentachlorobiphenyls 700 600 -- 650
Hexachlorobiphenyls 1200 1200 -- 1200
Heptachlorobiphenyls 270 300 -- 280
Octachlorobiphenyls 72 18 -- 45
     
Missouri River at Hermann, Mo., 15-gram sample Pentachlorobenzene 6.7 ND ND 6.7
Hexachlorobenzene 4.2 2.2 2.7 3
Pentachloroanisole 9.6 3.6 2.9 5.4
Chlorothalonil 0.98 0.44 ND 0.71
Pentachlorophenol ND 62 ND 62
Dachthal 1.6 1.5 1.1 1.4
Chlordane, cis- + trans- 68 62 54 61
Nonachlor, trans- 28 8 9.6 15
Pentachlorobiphenyls ND ND 260 260
Hexachlorobiphenyls 360 460 430 420
Heptachlorobiphenyls 22 34 39 32
Octachlorobiphenyls 10.3 8.9 5.2 8.1
Mississippi River at St. Louis, Mo., 15-gram sample Pentachlorobenzene 5.3 4.7 2.4 4.1
Hexachlorobenzene 5.1 3.9 3.7 4.2
Pentachloroanisole 11.1 7 6.2 8.1
Chlorothalonil 7.28 0.71 ND 4
Pentachlorophenol ND 192 ND 190
Dachthal 28 31 26 28
Chlordane, cis- + trans- 83 47 51 60
Nonachlor, trans- 35 23 19 26
Pentachlorobiphenyls ND 360 250 300
Hexachlorobiphenyls 470 470 410 450
Heptachlorobiphenyls 67 54 51 57
Octachlorobiphenyls 20 23 7.9 17
     
Mississippi River at Thebes, Ill., 15-gram sample Pentachlorobenzene 4 3.9 -- 4
Hexachlorobenzene 4.6 4.8 -- 4.7
Pentachloroanisole 12 12 -- 12
Chlorothalonil 0.44 ND -- 0.44
Pentachlorophenol 74 ND -- 74
Dachthal 17 15 -- 16
Chlordane, cis- + trans- 79 74 -- 76
Nonachlor, trans- 23 15 -- 19
Pentachlorobiphenyls 520 500 -- 510
Hexachlorobiphenyls 1,000 810 -- 920
Heptachlorobiphenyls 115 94 -- 100
Octachlorobiphenyls 31 24 -- 28
     
Ohio River at Olmsted, Ill., 8-gram sample Pentachlorobenzene ND ND 11 11
Hexachlorobenzene 14 28 27 23
Pentachloroanisole ND 5.7 5.6 5.6
Chlorothalonil ND 0.45 ND 0.45
Pentachlorophenol ND ND ND ND
Dachthal 3.4 5.6 5.2 4.7
Chlordane, cis- + trans- 17 60 58 45
Nonachlor, trans- ND 28 24 26
Pentachlorobiphenyls ND 500 400 450
Hexachlorobiphenyls 410 1,000 910 780
Heptachlorobiphenyls 50 160 150 120
Octachlorobiphenyls 17 28 10 18
     
Mississippi River below Hickman, Ky., 15-gram sample Pentachlorobenzene 12 10 -- 11
Hexachlorobenzene 20 19 -- 20
Pentachloroanisole 14 12 -- 13
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal 10.8 9.6 -- 10.2
Chlordane, cis- + trans- 58 60 -- 59
Nonachlor, trans- 14 18 -- 16
Pentachlorobiphenyls 660 490 -- 580
Hexachlorobiphenyls 1,100 990 -- 1,000
Heptachlorobiphenyls 130 140 -- 140
Octachlorobiphenyls 38 31 -- 34
     
Mississippi River at Fulton, Tenn., 15-gram sample Pentachlorobenzene 7.3 8.1 6.3 7.2
Hexachlorobenzene 12 12 12 12
Pentachloroanisole ND 7.2 2.4 4.8
Chlorothalonil 0.77 ND ND 0.77
Pentachlorophenol ND ND ND ND
Dachthal 3.6 ND ND 3.6
Chlordane, cis- + trans- 30 49 37 39
Nonachlor, trans- 21 14 13 16
Pentachlorobiphenyls ND 610 470 540
Hexachlorobiphenyls 1,200 1,300 1,000 1,200
Heptachlorobiphenyls 88 150 136 120
Octachlorobiphenyls 30 25 11 22
     
Mississippi River at Helena, Ark., 15-gram sample Pentachlorobenzene 7 6.9 -- 7
Hexachlorobenzene 15 14 -- 14
Pentachloroanisole 6.5 5.8 -- 6.2
Chlorothalonil 2.1 1.6 -- 1.8
Pentachlorophenol 33 ND -- 33
Dachthal 1.9 0.33 -- 1.1
Chlordane, cis- + trans- 71 64 -- 68
Nonachlor, trans- 24 20 -- 22
Pentachlorobiphenyls 440 430 -- 440
Hexachlorobiphenyls 960 870 -- 920
Heptachlorobiphenyls 170 140 -- 160
Octachlorobiphenyls 48 28 -- 38
     
White River at Mile 11.5, Ark., 15-gram sample Pentachlorobenzene 2.3 2.3 1.6 2.1
Hexachlorobenzene 3.7 3.5 1.5 2.9
Pentachloroanisole 2.9 2.9 2.1 2.6
Chlorothalonil ND ND ND ND
Pentachlorophenol ND ND ND ND
Dachthal 1.8 1.8 1.6 1.7
Chlordane, cis- + trans- 3.3 ND 5.4 4.4
Nonachlor, trans- ND ND 1.9 1.9
Pentachlorobiphenyls 142 72 64 93
Hexachlorobiphenyls 380 ND 430 400
Heptachlorobiphenyls 9.4 8.3 21.9 13
Octachlorobiphenyls 2.4 170 4 59
     
Mississippi River above Arkansas City, Ark., 15-gram sample Pentachlorobenzene 12.6 9.8 -- 11.2
Hexachlorobenzene 16 16 -- 16
Pentachloroanisole 9 8.5 -- 8.8
Chlorothalonil 1.7 1.6 -- 1.6
Pentachlorophenol ND ND -- ND
Dachthal 2.9 ND -- 2.9
Chlordane, cis- + trans- 61 80 -- 70
Nonachlor, trans- 15 16 -- 16
Pentachlorobiphenyls 440 460 -- 450
Hexachlorobiphenyls 1,300 970 -- 1,100
Heptachlorobiphenyls 190 190 -- 190
Octachlorobiphenyls 19 39 -- 29
     
Yazoo River at Mile 10.0, Miss., 15-gram sample Pentachlorobenzene 6.9 7.5 -- 7.2
Hexachlorobenzene 4.8 17.3 -- 11
Pentachloroanisole 5.8 6.9 -- 6.4
Chlorothalonil ND ND -- ND
Pentachlorophenol 34 ND -- 34
Dachthal 2.2 1.2 -- 1.7
Chlordane, cis- + trans- 8.8 13.6 -- 11
Nonachlor, trans- 2.9 5.6 -- 4.2
Pentachlorobiphenyls 86 81 -- 84
Hexachlorobiphenyls 310 310 -- 310
Heptachlorobiphenyls 10 14 -- 12
Octachlorobiphenyls 0.48 0.53 -- 0.5
     
Mississippi River below Vicksburg, Miss., 15-gram sample Pentachlorobenzene 11.1 10.9 8.7 10.2
Hexachlorobenzene 30 32 27 30
Pentachloroanisole 12.6 8.4 6.5 9.2
Chlorothalonil 6.1 2.3 1.8 3.4
Pentachlorophenol ND ND ND ND
Dachthal 8.8 6.5 5.4 6.9
Chlordane, cis- + trans- 84 65 53 67
Nonachlor, trans- 33.4 19.8 8.8 21
Pentachlorobiphenyls ND 470 360 420
Hexachlorobiphenyls 1,300 1,130 790 1,100
Heptachlorobiphenyls 180 170 170 170
Octachlorobiphenyls 50 11 15 25
     
Old River Outflow Channel near Knox Landing, La., 15-gram sample Pentachlorobenzene 6.6 12.1 9.6 9.4
Hexachlorobenzene 12 13 13 13
Pentachloroanisole 5.6 8.8 9.2 7.9
Chlorothalonil 1.3 ND 1.4 1.4
Pentachlorophenol ND ND ND ND
Dachthal 8.6 7.5 5.3 7.1
Chlordane, cis- + trans- 52 55 56 54
Nonachlor, trans- 13 10 17 13
Pentachlorobiphenyls ND 500 440 470
Hexachlorobiphenyls 1,100 1,100 1,000 1,100
Heptachlorobiphenyls 110 180 170 150
Octachlorobiphenyls 27 34 12 24
     
Mississippi River near St. Francisville, La., 15-gram sample Pentachlorobenzene 6 5.1 -- 5.6
Hexachlorobenzene 14 13 -- 14
Pentachloroanisole 6.5 5.1 -- 5.8
Chlorothalonil 1.3 0.4 -- 0.85
Pentachlorophenol 250 ND -- 250
Dachthal 3.5 2.5 -- 3
Chlordane, cis- + trans- 25 23 -- 24
Nonachlor, trans- 5.4 5.2 -- 5.3
Pentachlorobiphenyls 270 260 -- 260
Hexachlorobiphenyls 820 440 -- 630
Heptachlorobiphenyls 86 69 -- 78
Octachlorobiphenyls 10 8.3 -- 9.2
     
Mississippi River below Belle Chasse, La., 9-gram sample Pentachlorobenzene 8.2 7.4 -- 7.8
Hexachlorobenzene 39 36 -- 38
Pentachloroanisole 7 6.5 -- 6.8
Chlorothalonil 0.2 ND -- 0.2
Pentachlorophenol ND ND -- ND
Dachthal 0.47 ND -- 0.47
Chlordane, cis- + trans- 66 44 -- 55
Nonachlor, trans- 21.9 8.4 -- 15
Pentachlorobiphenyls 290 290 -- 290
Hexachlorobiphenyls 860 790 -- 820
Heptachlorobiphenyls 120 95.4 -- 110
Octachlorobiphenyls 42.7 1.3 -- 22

     

Table 6. Halogenated organic compounds found in suspended-sediment samples collected during the March-April 1989 cruise.

[ND, not detected; --, no data; masses not corrected for recovery; all masses rounded to two significant figures]

            Mass of compound, in nanograms
            Replicate samples
Sampling site and sample weight Compound A B C Average
Mississippi River near Winfield, Mo., 7.2-gram sample Pentachlorobenzene ND 6.6 7.6 7.1
Hexachlorobenzene 7 11 8.5 8.8
Pentachloroanisole 66 48 46 53
Chlorothalonil 6.7 1.5 3.1 3.8
Pentachlorophenol 600 1,500 670 920
Dachthal 6.7 10.4 10.1 9.1
Chlordane, cis- + trans- ND 49 37 43
Nonachlor, trans- ND 79 38 58
Pentachlorobiphenyls 1,300 1,100 900 1,100
Hexachlorobiphenyls 1,900 2,200 1,300 1,800
Heptachlorobiphenyls 24 73 36 44
Octachlorobiphenyls ND 20.4 1.6 11
     
Illinois River at Hardin, Ill., 39.96-gram sample Pentachlorobenzene 15 9.4 -- 12
Hexachlorobenzene 14 9.1 -- 12
Pentachloroanisole 50 32 -- 41
Chlorothalonil 2.7 1.8 -- 2.2
Pentachlorophenol 890 ND -- 890
Dachthal 17.2 8.4 -- 13
Chlordane, cis- + trans- 135 99 -- 120
Nonachlor, trans- 110 ND -- 110
Pentachlorobiphenyls 1,600 770 -- 1,200
Hexachlorobiphenyls 4,200 2,800 -- 3,500
Heptachlorobiphenyls 340 120 -- 230
Octachlorobiphenyls 68 37 -- 52
     
Missouri River at Hermann, Mo., 21.15-gram sample Pentachlorobenzene 5 5.8 -- 5.4
Hexachlorobenzene 5.3 4.6 -- 5
Pentachloroanisole 13 20 -- 16
Chlorothalonil 1.7 2.6 -- 2.2
Pentachlorophenol 750 950 -- 850
Dachthal 5.8 3.2 -- 4.5
Chlordane, cis- + trans- 30 18 -- 24
Nonachlor, trans- 57 ND -- 57
Pentachlorobiphenyls 94 ND -- 94
Hexachlorobiphenyls 270 620 -- 440
Heptachlorobiphenyls 20 20 -- 20
Octachlorobiphenyls ND ND -- ND
Mississippi River at St. Louis, Mo., 20.80-gram sample Pentachlorobenzene 4.6 5.1 -- 4.8
Hexachlorobenzene 8.1 4.5 -- 6.3
Pentachloroanisole 22 27 -- 24
Chlorothalonil 0.99 0.6 -- 0.8
Pentachlorophenol ND 1,400 -- 1,400
Dachthal 10.8 5.2 -- 8
Chlordane, cis- + trans- 53 51 -- 52
Nonachlor, trans- 32 108 -- 70
Pentachlorobiphenyls 520 220 -- 370
Hexachlorobiphenyls 1,700 1,100 -- 1,400
Heptachlorobiphenyls 51 30 -- 40
Octachlorobiphenyls 9.8 9 -- 9.4
                                   
Mississippi River at Thebes, Ill., 24.81-gram sample Pentachlorobenzene 12.3 3.5 -- 7.9
Hexachlorobenzene 8.2 6.4 -- 7.3
Pentachloroanisole 21 47 -- 34
Chlorothalonil 7 3.3 -- 5.2
Pentachlorophenol ND 540 -- 540
Dachthal 9.9 4.1 -- 7
Chlordane, cis- + trans- 99 76 -- 88
Nonachlor, trans- 110 130 -- 120
Pentachlorobiphenyls 2,000 340 -- 1,200
Hexachlorobiphenyls 1,200 1,200 -- 1,200
Heptachlorobiphenyls 85 56 -- 70
Octachlorobiphenyls 9 17 -- 13
                                   
Ohio River at Olmsted, Ill., 39.97-gram sample Pentachlorobenzene 35 26 -- 30
Hexachlorobenzene 73 70 -- 72
Pentachloroanisole 109 98 -- 104
Chlorothalonil ND 2.7 -- 2.7
Pentachlorophenol 760 ND -- 760
Dachthal 9.7 7 -- 800
Chlordane, cis- + trans- 108 98 -- 100
Nonachlor, trans- 150 260 -- 200
Pentachlorobiphenyls 580 860 -- 720
Hexachlorobiphenyls 4,400 4,800 -- 4,600
Heptachlorobiphenyls 200 230 -- 220
Octachlorobiphenyls 44 80 -- 62
                                   
Mississippi River below Hickman, Ky., 21.51-gram sample Pentachlorobenzene 11 21 -- 16
Hexachlorobenzene 21 26 -- 24
Pentachloroanisole 36 39 -- 38
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal 2.5 5 -- 3.8
Chlordane, cis- + trans- 34 67 -- 50
Nonachlor, trans- 80 101 -- 90
Pentachlorobiphenyls 570 670 -- 620
Hexachlorobiphenyls 1,600 2,400 -- 2,000
Heptachlorobiphenyls 71 170 -- 120
Octachlorobiphenyls 19 30.2 -- 25
     
Mississippi River below Fulton, Tenn., 39.87-gram sample Pentachlorobenzene 38 16 -- 27
Hexachlorobenzene 52 31 -- 42
Pentachloroanisole 91 70 -- 80
Chlorothalonil 6.8 ND -- 6.8
Pentachlorophenol ND ND -- ND
Dachthal 9.3 4.6 -- 7
Chlordane, cis- + trans- 87 57 -- 72
Nonachlor, trans- 220 120 -- 170
Pentachlorobiphenyls 1,400 550 -- 980
Hexachlorobiphenyls 4,900 1,800 -- 3,400
Heptachlorobiphenyls 320 124 -- 220
Octachlorobiphenyls 80 37 -- 58
     
Mississippi River at Helena, Ark., 39.96-gram sample Pentachlorobenzene 19 34 -- 26
Hexachlorobenzene 32 47 -- 40
Pentachloroanisole 57 62 -- 60
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal 5.1 5.7 -- 5.4
Chlordane, cis- + trans- 66 96 -- 81
Nonachlor, trans- 110 120 -- 120
Pentachlorobiphenyls 450 900 -- 680
Hexachlorobiphenyls 2,400 4,000 -- 3,200
Heptachlorobiphenyls 130 230 -- 180
Octachlorobiphenyls 24 45 -- 34
     
White River at Mile 11.5, Ark., 7.81-gram sample Pentachlorobenzene 5 5.2 6 5.4
Hexachlorobenzene 5.8 5.6 6.8 6.1
Pentachloroanisole 11.9 4.4 10.6 9
Chlorothalonil 0.5 ND 1.2 0.85
Pentachlorophenol 450 ND 400 420
Dachthal 7.8 5.2 7.8 6.9
Chlordane, cis- + trans- 8.2 4 24 12
Nonachlor, trans- 13 ND ND 13
Pentachlorobiphenyls 75 263 145 160
Hexachlorobiphenyls 480 240 360 360
Heptachlorobiphenyls 5.4 4 7.2 5.5
Octachlorobiphenyls 1.5 ND ND 1.5
     
Arkansas River at Pendleton, Ark., 11.86-gram sample Pentachlorobenzene ND 6.1 -- 6.1
Hexachlorobenzene 2.8 2.4 -- 2.6
Pentachloroanisole ND 32 -- 32
Chlorothalonil 1.6 1.5 -- 1.6
Pentachlorophenol ND ND -- ND
Dachthal 2.4 2.1 -- 2.2
Chlordane, cis- + trans- 28 35 -- 32
Nonachlor, trans- 81 ND -- 81
Pentachlorobiphenyls 160 550 -- 360
Hexachlorobiphenyls 520 310 -- 420
Heptachlorobiphenyls 15 14 -- 14
Octachlorobiphenyls 10 11 -- 10
     
Mississippi River above Arkansas City, Ark., 35.06-gram sample Pentachlorobenzene 17 21 -- 19
Hexachlorobenzene 33 33 -- 33
Pentachloroanisole 57 78 -- 68
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal ND 4.2 -- 4.2
Chlordane, cis- + trans- 59 69 -- 64
Nonachlor, trans- 92 115 -- 104
Pentachlorobiphenyls 1,600 930 -- 1,300
Hexachlorobiphenyls 3,400 3,500 -- 3,400
Heptachlorobiphenyls 150 180 -- 160
Octachlorobiphenyls 42 53 -- 48
Yazoo River below Steele Bayou, Miss., 37.31-gram sample Pentachlorobenzene 10 26 -- 18
Hexachlorobenzene 6.9 10.7 -- 8.8
Pentachloroanisole 30 37 -- 34
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal 2.9 2.1 -- 2.5
Chlordane, cis- + trans- 32 ND -- 32
Nonachlor, trans- ND ND -- ND
Pentachlorobiphenyls ND 310 -- 310
Hexachlorobiphenyls 210 720 -- 460
Heptachlorobiphenyls 20 31 -- 26
Octachlorobiphenyls ND 12 -- 12
     
Mississippi River below Vicksburg, Miss., 38.24-gram sample Pentachlorobenzene 23 17 27 22
Hexachlorobenzene 44 32 41 39
Pentachloroanisole 78 53 70 67
Chlorothalonil 4.1 2.6 3.3 3.3
Pentachlorophenol 820 ND ND 820
Dachthal 10 6.1 8.6 8.2
Chlordane, cis- + trans- 105 76 89 90
Nonachlor, trans- 220 96 140 152
Pentachlorobiphenyls 1,070 1,360 750 1,100
Hexachlorobiphenyls 2,600 3,100 2,600 2,800
Heptachlorobiphenyls 220 180 200 200
Octachlorobiphenyls 42 41 52 45
     
Old River Outflow Channel near Knox Landing, La., 39.96-gram sample Pentachlorobenzene 23 23 -- 23
Hexachlorobenzene 30 22 -- 26
Pentachloroanisole 45 41 -- 43
Chlorothalonil 2.4 ND -- 2.4
Pentachlorophenol 470 1,200 -- 840
Dachthal 7.2 6.4 -- 6.8
Chlordane, cis- + trans- 74 59 -- 66
Nonachlor, trans- 54 116 -- 85
Pentachlorobiphenyls 610 800 -- 700
Hexachlorobiphenyls 1,800 2,700 -- 2,200
Heptachlorobiphenyls 140 130 -- 140
Octachlorobiphenyls 29 40 -- 34
     
Mississippi River near St. Francisville, La., 34.36-gram sample Pentachlorobenzene 16 13 22 17
Hexachlorobenzene 19 18 23 20
Pentachloroanisole 68 46 54 56
Chlorothalonil 1 2 4.3 2.4
Pentachlorophenol 1,130 290 670 700
Dachthal 5.7 5.6 8.4 6.6
Chlordane, cis- + trans- 52 52 66 57
Nonachlor, trans- 84 50 99 78
Pentachlorobiphenyls 550 380 460 460
Hexachlorobiphenyls 1,700 1,600 2,000 1,800
Heptachlorobiphenyls 99 88 140 110
Octachlorobiphenyls 24 14 25 21
     
Mississippi River below Belle Chasse, La., 37.17-gram sample Pentachlorobenzene 30 34 26 30
Hexachlorobenzene 86 81 59 75
Pentachloroanisole 47 46 39 44
Chlorothalonil 4.8 4.4 ND 1.6
Pentachlorophenol ND 950 920 940
Dachthal 11 11 11 11
Chlordane, cis- + trans- 66 108 36 70
Nonachlor, trans- 77 106 105 96
Pentachlorobiphenyls 1,100 800 880 930
Hexachlorobiphenyls 3,000 2,500 2,400 2,600
Heptachlorobiphenyls 120 160 130 140
Octachlorobiphenyls 36 26 41 34

     

     

Table 7. Halogenated organic compounds found in suspended-sediment samples collected during the June 1989 cruise.

[ND, not detected; --, no data; masses not corrected for recovery; all masses rounded to two significant figures]

            Mass of compound, in nanograms
            Replicate samples      
Sampling site and sample weight Compound A B C D E Average
Mississippi River near Winfield, Mo., 19.90-gram sample Pentachlorobenzene 1 ND -- -- -- 1
Hexachlorobenzene 3 2.1 -- -- -- 2.6
Pentachloroanisole ND ND -- -- -- ND
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 7 4 -- -- -- 5.5
Chlordane, cis- + trans- 13 ND -- -- -- 13
Nonachlor, trans- ND ND -- -- -- ND
Pentachlorobiphenyls 540 260 -- -- -- 400
Hexachlorobiphenyls 1,400 510 -- -- -- 960
Heptachlorobiphenyls 20.7 6.9 -- -- -- 14
Octachlorobiphenyls ND ND -- -- -- ND
     
Illinois River at Hardin, Ill., 39.74-gram sample Pentachlorobenzene 18 27 -- -- -- 22
Hexachlorobenzene ND 3.3 -- -- -- 303
Pentachloroanisole ND ND -- -- -- ND
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 12 22 -- -- -- 17
Chlordane, cis- + trans- 21 129 -- -- -- 75
Nonachlor, trans- ND 150 -- -- -- 150
Pentachlorobiphenyls 140 1,300 -- -- -- 720
Hexachlorobiphenyls 970 3,400 -- -- -- 2,200
Heptachlorobiphenyls 31 180 -- -- -- 110
Octachlorobiphenyls ND 30 -- -- -- 30
     
Missouri River at Hermann, Mo., 40.11-gram sample Pentachlorobenzene 3.6 1.3 -- -- -- 2.4
Hexachlorobenzene 4.9 2.6 -- -- -- 3.8
Pentachloroanisole 4.3 1.8 -- -- -- 3
Chlorothalonil 1.2 ND -- -- -- 1.2
Pentachlorophenol 130 ND -- -- -- 130
Dachthal 7.8 4.7 -- -- -- 6.2
Chlordane, cis- + trans- 31 18 -- -- -- 24
Nonachlor, trans- 41 15 -- -- -- 28
Pentachlorobiphenyls 47 ND -- -- -- 47
Hexachlorobiphenyls 310 150 -- -- -- 230
Heptachlorobiphenyls 15.5 6.4 -- -- -- 11
Octachlorobiphenyls 1.4 ND -- -- -- 1.4
Mississippi River at St. Louis, Mo., 40.17-gram sample Pentachlorobenzene 7.2 7.9 -- -- -- 7.6
Hexachlorobenzene 7.2 7.5 -- -- -- 7.4
Pentachloroanisole 16 14 -- -- -- 15
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 15 14 -- -- -- 14
Chlordane, cis- + trans- 54 48 -- -- -- 51
Nonachlor, trans- 60 62 -- -- -- 61
Pentachlorobiphenyls 410 410 -- -- -- 410
Hexachlorobiphenyls 1,400 1,300 -- -- -- 1,400
Heptachlorobiphenyls 60 58 -- -- -- 59
Octachlorobiphenyls 9.9 11 -- -- -- 10
     
Mississippi River at Thebes, Ill., 30.99-gram sample Pentachlorobenzene 5.4 5.7 -- -- -- 5.6
Hexachlorobenzene 5.1 5.5 -- -- -- 5.3
Pentachloroanisole 11 12 -- -- -- 12
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 11 11 -- -- -- 11
Chlordane, cis- + trans- 60 55 -- -- -- 58
Nonachlor, trans- 68 68 -- -- -- 68
Pentachlorobiphenyls 500 420 -- -- -- 460
Hexachlorobiphenyls 1,500 1,600 -- -- -- 1,600
Heptachlorobiphenyls 104 96 -- -- -- 100
Octachlorobiphenyls 20 16 -- -- -- 18
     
Ohio River at Olmsted, Ill., 40.21-gram sample Pentachlorobenzene 26 25 -- -- -- 26
Hexachlorobenzene 92 88 -- -- -- 90
Pentachloroanisole 41 37 -- -- -- 39
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 22 22 -- -- -- 22
Chlordane, cis- + trans- 67 64 -- -- -- 66
Nonachlor, trans- 140 120 -- -- -- 130
Pentachlorobiphenyls 1,400 1,500 -- -- -- 1,400
Hexachlorobiphenyls 3,000 3,200 -- -- -- 3,100
Heptachlorobiphenyls 170 160 -- -- -- 160
Octachlorobiphenyls 33 26 -- -- -- 30
     
Mississippi River below Hickman, Ky., 37.94-gram sample Pentachlorobenzene 15 15 -- -- -- 15
Hexachlorobenzene 57 56 -- -- -- 56
Pentachloroanisole 20 24 -- -- -- 22
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 15 14 -- -- -- 14
Chlordane, cis- + trans- 64 71 -- -- -- 68
Nonachlor, trans- 91 101 -- -- -- 96
Pentachlorobiphenyls 1,300 1,400 -- -- -- 1,400
Hexachlorobiphenyls 2,600 2,700 -- -- -- 2,600
Heptachlorobiphenyls 146 144 -- -- -- 140
Octachlorobiphenyls 23 22 -- -- -- 22
     
Mississippi River at Fulton, Tenn., 37.47-gram sample Pentachlorobenzene 16 18 -- -- -- 17
Hexachlorobenzene 40 41 -- -- -- 40
Pentachloroanisole 11 21 -- -- -- 14
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 11 12 -- -- -- 12
Chlordane, cis- + trans- 40 42 -- -- -- 41
Nonachlor, trans- 45 44 -- -- -- 44
Pentachlorobiphenyls 670 820 -- -- -- 740
Hexachlorobiphenyls 2,200 2,100 -- -- -- 2,200
Heptachlorobiphenyls 96 107 -- -- -- 100
Octachlorobiphenyls 16 18 -- -- -- 17
     
Mississippi River at Helena, Ark., 40.10-gram sample Pentachlorobenzene 15 16 -- -- -- 16
Hexachlorobenzene 34 34 -- -- -- 34
Pentachloroanisole 18 16 -- -- -- 17
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 10.2 8.6 -- -- -- 9.4
Chlordane, cis- + trans- 34 36 -- -- -- 35
Nonachlor, trans- 41 ND -- -- -- 41
Pentachlorobiphenyls 750 600 -- -- -- 680
Hexachlorobiphenyls 2,200 2,200 -- -- -- 2,200
Heptachlorobiphenyls 102 96 -- -- -- 99
Octachlorobiphenyls 19 18 -- -- -- 18
     
White River at Mile 11.5, Ark., 28.99-gram sample Pentachlorobenzene 5.1 4.6 -- -- -- 4.8
Hexachlorobenzene 6.2 5.6 -- -- -- 5.9
Pentachloroanisole ND ND -- -- -- ND
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 7.4 7.2 -- -- -- 7.3
Chlordane, cis- + trans- ND ND -- -- -- ND
Nonachlor, trans- ND ND -- -- -- ND
Pentachlorobiphenyls ND ND -- -- -- ND
Hexachlorobiphenyls ND ND -- -- -- ND
Heptachlorobiphenyls ND ND -- -- -- ND
Octachlorobiphenyls ND ND -- -- -- ND
     
Arkansas River at Pendleton, Ark., 15.03-gram sample Pentachlorobenzene ND ND -- -- -- ND
Hexachlorobenzene ND ND -- -- -- ND
Pentachloroanisole ND ND -- -- -- ND
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 2.9 2.8 -- -- -- 2.8
Chlordane, cis- + trans- ND ND -- -- -- ND
Nonachlor, trans- ND ND -- -- -- ND
Pentachlorobiphenyls ND ND -- -- -- ND
Hexachlorobiphenyls 44 90 -- -- -- 67
Heptachlorobiphenyls 5.1 4.4 -- -- -- 4.8
Octachlorobiphenyls ND ND -- -- -- ND
     
Mississippi River above Arkansas City, Ark., 39.44-gram sample Pentachlorobenzene 11 15 -- -- -- 13
Hexachlorobenzene 38 38 -- -- -- 38
Pentachloroanisole 14 14 -- -- -- 14
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 8.7 9 -- -- -- 8.8
Chlordane, cis- + trans- 23 21 -- -- -- 22
Nonachlor, trans- ND ND -- -- -- ND
Pentachlorobiphenyls 610 500 -- -- -- 560
Hexachlorobiphenyls 2,100 1,900 -- -- -- 2,000
Heptachlorobiphenyls 110 84 -- -- -- 97
Octachlorobiphenyls 15 12 -- -- -- 14
     
Yazoo River below Steele Bayou, Miss., 40.22-gram sample Pentachlorobenzene 16 ND -- -- -- 16.3
Hexachlorobenzene 3.4 ND -- -- -- 3.41
Pentachloroanisole 9.6 ND -- -- -- 9.62
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 1.8 ND -- -- -- 1.78
Chlordane, cis- + trans- ND ND -- -- -- ND
Nonachlor, trans- ND ND -- -- -- ND
Pentachlorobiphenyls ND ND -- -- -- ND
Hexachlorobiphenyls ND ND -- -- -- ND
Heptachlorobiphenyls ND ND -- -- -- ND
Octachlorobiphenyls ND ND -- -- -- ND
     
Mississippi River below Vicksburg, Miss., 39.01-gram sample Pentachlorobenzene 12 21 ND ND 17 17
Hexachlorobenzene 39 48 27 32 42 38
Pentachloroanisole 5.6 24 ND ND 16 15
Chlorothalonil ND ND ND ND ND ND
Pentachlorophenol ND ND ND ND ND ND
Dachthal 6.4 10.7 ND 5.2 8 7.6
Chlordane, cis- + trans- ND 40 ND ND 21 30
Nonachlor, trans- ND 49 ND ND 16 32
Pentachlorobiphenyls 270 770 ND ND 480 510
Hexachlorobiphenyls 1,400 2,000 450 980 1,900 1,300
Heptachlorobiphenyls 74 157 28 40 90 78
Octachlorobiphenyls 13 30 ND ND 16 20
     
Old River Outflow Channel near Knox Landing, La., 35.86-gram sample Pentachlorobenzene 13 16 -- -- -- 14
Hexachlorobenzene 31 29 -- -- -- 30
Pentachloroanisole 18 16 -- -- -- 17
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 5.9 5.5 -- -- -- 5.7
Chlordane, cis- + trans- 25 27 -- -- -- 26
Nonachlor, trans- 25 30 -- -- -- 28
Pentachlorobiphenyls 420 490 -- -- -- 460
Hexachlorobiphenyls 1,700 1,700 -- -- -- 1,700
Heptachlorobiphenyls 90 92 -- -- -- 91
Octachlorobiphenyls 14 16 -- -- -- 15
     
Mississippi River near St. Francisville, La., 39.79-gram sample Pentachlorobenzene 17 18 -- -- -- 18
Hexachlorobenzene 39 37 -- -- -- 38
Pentachloroanisole 17 16 -- -- -- 16
Chlorothalonil ND ND -- -- -- ND
Pentachlorophenol ND ND -- -- -- ND
Dachthal 7.5 6.8 -- -- -- 7.2
Chlordane, cis- + trans- 36 29 -- -- -- 32
Nonachlor, trans- 31 18 -- -- -- 24
Pentachlorobiphenyls 530 600 -- -- -- 560
Hexachlorobiphenyls 1,800 1,700 -- -- -- 1,800
Heptachlorobiphenyls 98 87 -- -- -- 92
Octachlorobiphenyls 18 15 -- -- -- 16
     
Mississippi River below Belle Chasse, La., 39.78-gram sample Pentachlorobenzene 12 15 17 5.8 -- 12
Hexachlorobenzene 110 130 130 100 -- 120
Pentachloroanisole ND 17 20 ND -- 18
Chlorothalonil ND ND ND ND -- ND
Pentachlorophenol ND ND ND ND -- ND
Dachthal 6.6 7 7.6 5 -- 6.6
Chlordane, cis- + trans- ND ND 19 ND -- 19
Nonachlor, trans- ND ND ND ND -- ND
Pentachlorobiphenyls 220 680 410 100 -- 350
Hexachlorobiphenyls 1,200 2,700 1,600 730 -- 1,600
Heptachlorobiphenyls 54 107 86 41 -- 72
Octachlorobiphenyls 6.6 23 17 ND -- 16

     

Table 8. Halogenated organic compounds found in suspended-sediment samples collected during the February-March 1990 cruise.

[ND, not detected; --, no data; masses not corrected for recovery; all masses rounded to two significant figures]

            Mass of compound, in nanograms
            Replicate samples
Sampling site and sample weight Compound A B C Average
Mississippi River near Cache, Ill., 20.19-gram sample Pentachlorobenzene ND ND -- ND
Hexachlorobenzene 1.8 3.5 -- 2.6
Pentachloroanisole 18 46 -- 32
Chlorothalonil ND 0.78 -- 0.78
Pentachlorophenol ND ND -- ND
Dachthal 2 3.1 -- 2.6
Chlordane, cis- + trans- 53 ND -- 53
Nonachlor, trans- 23 ND -- 23
Pentachlorobiphenyls 460 480 -- 470
Hexachlorobiphenyls 1,700 1,600 -- 1,600
Heptachlorobiphenyls 79 46 -- 62
Octachlorobiphenyls 17 12 -- 14
     
Ohio River at Uniontown, Ky., 20.04-gram sample Pentachlorobenzene 22 12 -- 17
Hexachlorobenzene 110 80 -- 95
Pentachloroanisole 63 71 -- 67
Chlorothalonil ND 3.2 -- 3.2
Pentachlorophenol 620 ND -- 620
Dachthal 3.5 ND -- 3.5
Chlordane, cis- + trans- 73 ND -- 73
Nonachlor, trans- 130 ND -- 130
Pentachlorobiphenyls 1,300 890 -- 1,100
Hexachlorobiphenyls 3,800 3,900 -- 3,800
Heptachlorobiphenyls 290 130 -- 210
Octachlorobiphenyls 60 20 -- 40
     
Wabash River near New Haven, Ill., 21.61-gram sample Pentachlorobenzene ND 2.9 -- 2.9
Hexachlorobenzene 2.7 5.8 -- 4.2
Pentachloroanisole 32 49 -- 40
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal 2.4 2.6 -- 2.5
Chlordane, cis- + trans- 66 ND -- 66
Nonachlor, trans- 120 ND -- 120
Pentachlorobiphenyls 260 290 -- 280
Hexachlorobiphenyls 520 500 -- 510
Heptachlorobiphenyls 20 17 -- 18
Octachlorobiphenyls 0.9 3.3 -- 2.1
     
Cumberland River near Smithland, Ky., 6.24-gram sample Pentachlorobenzene 2.2 ND -- 2.2
Hexachlorobenzene 4.7 ND -- 4.7
Pentachloroanisole 7.1 11.7 -- 9.4
Chlorothalonil ND 1.2 -- 1.2
Pentachlorophenol 510 ND -- 510
Dachthal 1 ND -- 1
Chlordane, cis- + trans- 13 ND -- 13
Nonachlor, trans- ND ND -- ND
Pentachlorobiphenyls 190 ND -- 190
Hexachlorobiphenyls 420 ND -- 420
Heptachlorobiphenyls 16 ND -- 16
     
Tennessee River near Calvert City, Ky., 8.14-gram sample Pentachlorobenzene 2.8 ND -- 2.8
Hexachlorobenzene 7.1 7.4 -- 7.2
Pentachloroanisole 6.7 9.3 -- 8
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal 0.71 ND -- 0.71
Chlordane, cis- + trans- 6.6 6.7 -- 6.65
Nonachlor, trans- ND ND -- ND
Pentachlorobiphenyls 140 ND -- 140
Hexachlorobiphenyls 330 260 -- 300
Heptachlorobiphenyls 21 7.1 -- 14
Octachlorobiphenyls 0.69 0.7 -- 0.7
     
Ohio River at Olmsted, Ill., 21.50-gram sample Pentachlorobenzene 14 13 -- 14
Hexachlorobenzene 90 73 -- 82
Pentachloroanisole 48 57 -- 52
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal ND ND -- ND
Chlordane, cis- + trans- 67 44 -- 56
Nonachlor, trans- 140 130 -- 140
Pentachlorobiphenyls 800 800 -- 800
Hexachlorobiphenyls 3,000 2,400 -- 2,700
Heptachlorobiphenyls 180 93 -- 140
Octachlorobiphenyls 40 24 -- 32
     
Mississippi River below Hickman, Ky., 19.04-gram sample Pentachlorobenzene 13 10 -- 12
Hexachlorobenzene 64 65 -- 64
Pentachloroanisole 39 37 -- 38
Chlorothalonil ND ND -- ND
Pentachlorophenol ND 720 -- 720
Dachthal 2.1 1.7 -- 1.9
Chlordane, cis- + trans- 26 40 -- 33
Nonachlor, trans- 110 70 -- 90
Pentachlorobiphenyls 440 340 -- 390
Hexachlorobiphenyls 2,360 1,400 -- 1,900
Heptachlorobiphenyls 108 55 -- 82
Octachlorobiphenyls 25 15 -- 20
     
Mississippi River below Fulton, Tenn., 19.48-gram sample Pentachlorobenzene 13.4 9.2 -- 11
Hexachlorobenzene 91 86 -- 88
Pentachloroanisole 30 37 -- 34
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal 0.8 2.4 -- 1.6
Chlordane, cis- + trans- 48 56 -- 52
Nonachlor, trans- 126 36 -- 81
Pentachlorobiphenyls 1000 680 -- 840
Hexachlorobiphenyls 2,300 1,800 -- 2,000
Heptachlorobiphenyls 93 74 -- 84
Octachlorobiphenyls 11 22 -- 16
     
Mississippi River at Helena, Ark., 18.97-gram sample Pentachlorobenzene 6.1 9.6 -- 7.8
Hexachlorobenzene 24 32 -- 28
Pentachloroanisole 40 41 -- 40
Chlorothalonil ND ND -- ND
Pentachlorophenol 200 ND -- 200
Dachthal 1 2.2 -- 1.6
Chlordane, cis- + trans- 35 46 -- 40
Nonachlor, trans- 65 60 -- 62
Pentachlorobiphenyls 240 580 -- 410
Hexachlorobiphenyls 1,500 1,300 -- 1,400
Heptachlorobiphenyls 68 58 -- 63
Octachlorobiphenyls 17 16 -- 16
     
Mississippi River above Arkansas City, Ark., 17.26-gram sample Pentachlorobenzene 5.4 6 -- 5.7
Hexachlorobenzene 18 28 -- 23
Pentachloroanisole 25 26 -- 25.5
Chlorothalonil ND ND -- ND
Pentachlorophenol ND 770 -- 770
Dachthal 0.76 1.13 -- 0.94
Chlordane, cis- + trans- 22 22 -- 22
Nonachlor, trans- 72 ND -- 72
Pentachlorobiphenyls 640 760 -- 700
Hexachlorobiphenyls 170 1,000 -- 585
Heptachlorobiphenyls 49 37 -- 43
Octachlorobiphenyls 8.8 11 -- 9.9
     
Mississippi River below Vicksburg, Miss., 20.46-gram sample Pentachlorobenzene 5.3 4.6 -- 5
Hexachlorobenzene 14 23 -- 18
Pentachloroanisole 33 35 -- 34
Chlorothalonil ND 1.9 -- 1.9
Pentachlorophenol ND ND -- ND
Dachthal ND 1.7 -- 1.7
Chlordane, cis- + trans- 19 26 -- 22
Nonachlor, trans- ND 49 -- 49
Pentachlorobiphenyls 220 490 -- 360
Hexachlorobiphenyls 860 1,300 -- 1,100
Heptachlorobiphenyls 43 78 -- 60
Octachlorobiphenyls 13 15 -- 14
     
Mississippi River near St. Francisville, La., 15.55-gram sample Pentachlorobenzene ND 13 -- 13
Hexachlorobenzene 7.7 9.7 -- 8.7
Pentachloroanisole 13 26 -- 20
Chlorothalonil ND 1.5 -- 1.5
Pentachlorophenol ND ND -- ND
Dachthal ND ND -- ND
Chlordane, cis- + trans- ND 23 -- 23
Nonachlor, trans- ND ND -- ND
Pentachlorobiphenyls 480 420 -- 450
Hexachlorobiphenyls 640 1,100 -- 870
Heptachlorobiphenyls 28 42 -- 35
Octachlorobiphenyls 11 8.3 -- 10
     
Mississippi River below Belle Chasse, La., 20.12-gram sample Pentachlorobenzene 5.1 11.4 -- 8.2
Hexachlorobenzene 29 43 -- 36
Pentachloroanisole 20 25 -- 22
Chlorothalonil 0.63 1.21 -- 0.92
Pentachlorophenol ND ND -- ND
Dachthal 0.52 1.45 -- 0.99
Chlordane, cis- + trans- 18 42 -- 30
Nonachlor, trans- 34 ND -- 34
Pentachlorobiphenyls 160 350 -- 260
Hexachlorobiphenyls 600 1,100 -- 850
Heptachlorobiphenyls 36 48 -- 42
Octachlorobiphenyls 11 15 -- 13

     

Table 9. Halogenated organic compounds found in suspended-sediment samples collected during the May-June 1990 cruise.

[ND, not detected; --, no data; masses not corrected for recovery; all masses rounded to two significant figures]

            Mass of compound, in nanograms
            Replicate samples
Sampling site and sample weight Compound A B C Average
Illinois River at Valley City, Ill., 21.735-gram sample Pentachlorobenzene 2.5 2.5 -- 2.5
Hexachlorobenzene 5.1 4.6 -- 4.8
Pentachloroanisole 12 11 -- 12
Chlorothalonil 3.1 4 -- 3.6
Pentachlorophenol 190 120 -- 160
Dachthal 10.2 9.2 -- 9.7
Chlordane, cis- + trans- 46 44 -- 45
Nonachlor, trans- 36 29 -- 32
Pentachlorobiphenyls 380 340 -- 360
Hexachlorobiphenyls 1,900 1,500 -- 1,700
Heptachlorobiphenyls 66 63 -- 64
Octachlorobiphenyls 18 19 -- 18
     
Mississippi River below Grafton, Ill., 100.034-gram sample Pentachlorobenzene 5 4.5 -- 4.8
Hexachlorobenzene 15 13 -- 14
Pentachloroanisole 12 10 -- 11
Chlorothalonil 12.1 7.8 -- 10
Pentachlorophenol 220 ND -- 220
Dachthal 4 2.8 -- 3.4
Chlordane, cis- + trans- 59 ND -- 59
Nonachlor, trans- 38 ND -- 38
Pentachlorobiphenyls 540 430 -- 480
Hexachlorobiphenyls 4,000 1,800 -- 2,900
Heptachlorobiphenyls 99 69 -- 84
Octachlorobiphenyls 35 13 -- 24
     
Mississippi River at Thebes, Ill., 69.657-gram sample Pentachlorobenzene 4.4 4.4 8.6 5.8
Hexachlorobenzene 9.3 9.6 11.8 10
Pentachloroanisole 24 20 22 22
Chlorothalonil ND 1.9 ND 1.9
Pentachlorophenol 860 830 1,679 1,100
Dachthal 4.8 5.4 7 5.7
Chlordane, cis- + trans- 60 24 37 40
Nonachlor, trans- 38 17 26 27
Pentachlorobiphenyls 210 460 190 290
Hexachlorobiphenyls 570 1,500 940 1,000
Heptachlorobiphenyls 17 44 33 31
Octachlorobiphenyls 2.8 9.9 6.8 6.5
     
Ohio River at Olmsted, Ill., 38.585-gram sample Pentachlorobenzene 19 16 17 17
Hexachlorobenzene 170 160 150 160
Pentachloroanisole 65 58 56 60
Chlorothalonil 3.5 4.5 3.2 3.7
Pentachlorophenol 510 310 370 400
Dachthal 6.1 6.6 6.5 6.4
Chlordane, cis- + trans- 32 39 67 46
Nonachlor, trans- 34 34 66 45
Pentachlorobiphenyls 520 650 450 540
Hexachlorobiphenyls 1,900 2,700 1,800 2,100
Heptachlorobiphenyls 94 149 70 100
Octachlorobiphenyls 20 40 17 26
     
Mississippi River below Memphis, Tenn., 50.890-gram sample Pentachlorobenzene 7.5 6.8 7.9 7.4
Hexachlorobenzene 49 52 42 48
Pentachloroanisole 44 44 40 43
Chlorothalonil 1 33 2 12
Pentachlorophenol 390 320 440 380
Dachthal 4.1 4.4 4.1 4.2
Chlordane, cis- + trans- 14 57 30 34
Nonachlor, trans- 9.8 54 31 32
Pentachlorobiphenyls 570 520 350 480
Hexachlorobiphenyls 2,100 1,700 1,800 1,900
Heptachlorobiphenyls 110 73 67 83
Octachlorobiphenyls 31 20 22 24
     
Mississippi River below Memphis, Tenn., 73.072-gram sample Pentachlorobenzene 13 12 40 22
Hexachlorobenzene 88 79 76 81
Pentachloroanisole 18 24 35 26
Chlorothalonil 11.3 3.1 ND 7.2
Pentachlorophenol 390 170 380 310
Dachthal 4 4.5 17.8 8.8
Chlordane, cis- + trans- 62 64 73 66
Nonachlor, trans- 73 56 84 71
Pentachlorobiphenyls 780 430 600 600
Hexachlorobiphenyls 3,000 2,300 3,800 3,000
Heptachlorobiphenyls 120 120 190 140
Octachlorobiphenyls 69 62 64 65
     
Mississippi River below Arkansas City, Ark., 53.084-gram sample Pentachlorobenzene 10.5 10.4 9.2 10
Hexachlorobenzene 22 22 18 21
Pentachloroanisole 41 36 35 37
Chlorothalonil 2.4 4.4 3.5 3.4
Pentachlorophenol 360 240 250 280
Dachthal 7.1 7.7 6.4 7
Chlordane, cis- + trans- 42 21 20 28
Nonachlor, trans- 32 18 16 22
Pentachlorobiphenyls 260 300 360 310
Hexachlorobiphenyls 1,700 2,100 1,700 1,800
Heptachlorobiphenyls 74 116 78 89
Octachlorobiphenyls 16 37 25 26
     
Mississippi River below Vicksburg, Miss., 49.499-gram sample Pentachlorobenzene 8.5 10.6 -- 9.6
Hexachlorobenzene 20 18 -- 19
Pentachloroanisole 29 23 -- 26
Chlorothalonil ND ND -- ND
Pentachlorophenol ND ND -- ND
Dachthal 4.6 4.1 -- 4.4
Chlordane, cis- + trans- ND ND -- ND
Nonachlor, trans- ND ND -- ND
Pentachlorobiphenyls 550 160 -- 360
Hexachlorobiphenyls 4,100 3,500 -- 3,800
Heptachlorobiphenyls 140 110 -- 120
Octachlorobiphenyls 23 19 -- 21
     
Mississippi River below Vicksburg, Miss., 31.603-gram sample Pentachlorobenzene 4 4.9 -- 4.4
Hexachlorobenzene 26 41 -- 34
Pentachloroanisole 19.2 5.4 -- 12
Chlorothalonil 15 27 -- 21
Pentachlorophenol 160 310 -- 240
Dachthal 1.1 1.3 -- 1.2
Chlordane, cis- + trans- 17 22 -- 20
Nonachlor, trans- ND 14 -- 14
Pentachlorobiphenyls 170 140 -- 160
Hexachlorobiphenyls 1,700 1,900 -- 1,800
Heptachlorobiphenyls 47 46 -- 46
Octachlorobiphenyls 69 25 -- 47
     
Mississippi River near St. Francisville, La., 56.237-gram sample Pentachlorobenzene 15 15 -- 15
Hexachlorobenzene 31 29 -- 30
Pentachloroanisole 48 43 -- 46
Chlorothalonil 3.2 7.6 -- 5.4
Pentachlorophenol 230 260 -- 240
Dachthal 7.3 7 -- 7.2
Chlordane, cis- + trans- 18 32 -- 25
Nonachlor, trans- 19 27 -- 23
Pentachlorobiphenyls 370 320 -- 340
Hexachlorobiphenyls 2,000 2,000 -- 2,000
Heptachlorobiphenyls 103 74 -- 88
Octachlorobiphenyls 28 29 -- 28
     
Mississippi River below Belle Chasse, La., 54.391-gram sample Pentachlorobenzene 17 15 -- 16
Hexachlorobenzene 73 67 -- 70
Pentachloroanisole 40 35 -- 38
Chlorothalonil 1.1 1.2 -- 1.2
Pentachlorophenol 180 220 -- 200
Dachthal 5.6 5.4 -- 5.5
Chlordane, cis- + trans- 19 14 -- 16
Nonachlor, trans- 12 390 -- 200
Pentachlorobiphenyls 420 270 -- 340
Hexachlorobiphenyls 2,400 2,000 -- 2,200
Heptachlorobiphenyls 130 110 -- 120
Octachlorobiphenyls 39 27 -- 33

     

The data were not censored below the detection limit to avoid statistical distortions of the data that can occur (Helsel and Cohn, 1988). When no response occurred for a compound, a "not detected" (ND) designation is used. According to Helsel (1990), "deletion of censored data or fabrication of values for less-thans leads to undesirable and unnecessary errors."

Halogenated organic compounds found associated with suspended sediment in samples collected during the May-June 1988 cruise are shown in table 5. Sixteen sites were sampled during this cruise. The usual sample size was 15 g although less suspended sediment was available from some sites, such as the Ohio River at Olmsted.

Halogenated organic compounds found associated with suspended sediment in samples from 17 sites from the March-April 1989 cruise are shown in table 6. Spring runoff conditions on the Ohio River resulted in higher suspended-sediment concentrations, as seen in table 2, than in May-June 1988. Larger sample sizes of nearly 40 g were extracted when available.

Suspended-sediment data from samples collected at 17 sites from the June 1989 cruise are shown in table 7. Spring runoff conditions on the Missouri River again produced high suspended-sediment concentrations on the Mississippi River, enabling larger sample sizes to be collected and extracted.

During the February-March 1990 cruise, samples were collected at only 13 sites, many of them different from previous trips, as shown in table 8. Sample sizes averaged about 18 g.

The organic compound data for samples collected during the May-June 1990 cruise are shown in table 9. The extracted sample sizes varied widely. A new, higher capacity balance allowed sample weights to be measured to thousandths of a gram.

The relative standard deviation (RSD) was determined for the replicate analyses of each compound for each sample, data permitting. For each cruise, the average RSD was determined for each compound and is shown in table 10, along with an average for all cruises.

Table 10. Average relative standard deviation, in percent, for replicate analyses.

[--, insufficient data for calculation]

      Cruise      
Compound May-June 1988 March-April 1989 June 1989 February-March 1990 May-June 1990 Average
Pentachlorobenzene 15 29 17 24 17 20
Hexachlorobenzene 16 19 9 22 10 15
Pentachloroanisole 20 20 20 20 18 19
Chlorothalonil 50 38 -- 44 48 45
Pentachlorophenol -- 34 -- -- 27 30
Dachthal 25 29 13 39 17 25
Chlordane, cis- + trans- 18 26 20 21 31 23
Nonachlor, trans- 29 34 23 31 48 33
Pentachlorobiphenyls 13 42 28 24 27 27
Hexachlorobiphenyls 15 29 25 26 20 23
Heptachlorobiphenyls 19 29 27 33 23 26
Octachlorobiphenyls 52 35 17 30 32 34

At the Missouri River site on June 7, 1989, there was sufficient material from the depth-integrated composite sample to compare it with the pumped composite sample. Both suspended-sediment samples were discharge-weighted water samples taken at each vertical; however, the pumped sample was not depth integrated. Different sample sizes were extracted. Table 11 includes compound mass and sample weight of the suspended sediment from the discharge-weighted samples collected by pumping and by depth integration.

The suspended-sediment extracts from 17 samples collected during the June 1989 cruise and 8 samples collected during the February-March 1990 cruise were reanalyzed for EPA priority pollutants. The concentration, in microgram/kg of dry suspended sediment (rather than mass as in previous tables), of each of the selected priority pollutants in selected samples is presented in table 12 for the June 1989 cruise and table 13 for the February-March 1990 cruise. The compounds of primary interest were the polycyclic aromatic hydrocarbons.

Table 11. Halogenated organic compounds in suspended-sediment depth-integrated and pumped samples collected June 7, 1989 from the Missouri River at Hermann, Missouri.

[ND, not detected]

            Mass in nanograms
            Replicates      
Sample type and weight Compound A B Average
Pumped, 40.11-gram sample Pentachlorobenzene 3.66 1.3 2.5
Hexachlorobenzene 4.9 2.6 3.8
Pentachloroanisole 4.3 1.8 3
Chlorothalonil 1.2 ND 1.2
Pentachlorophenol 130 ND 130
Dachthal 7.8 4.7 6.2
Chlordane, cis- + trans- 31 18 24
Nonachlor, trans- 41 15 28
Pentachlorobiphenyls 47 ND 47
Hexachlorobiphenyls 310 150 231
Heptachlorobiphenyls 15.5 6.4 11
Octachlorobiphenyls 1.4 ND 1.4
     
Depth integrated, 21.16-gram sample Pentachlorobenzene 4.4 5.1 4.8
Hexachlorobenzene 5.1 5.2 5.2
Pentachloroanisole 3.9 2.4 3.2
Chlorothalonil ND ND ND
Pentachlorophenol ND ND ND
Dachthal 8.2 8.4 8.3
Chlordane, cis- + trans- 7.5 5.8 6.6
Nonachlor, trans- ND 6.8 6.8
Pentachlorobiphenyls 34 15 24.5
Hexachlorobiphenyls 76 73 74.6
Heptachlorobiphenyls 3.4 3.8 3.6
Octachlorobiphenyls ND ND ND

Table 12. Hydrophobic U.S. Environmental Protection Agency priority pollutants detected in suspended-sediment samples collected during the June 1989 cruise.

[All concentrations in micrograms per kilogram dry sediment; ND, not detected]

      Sampling site
Compound Mississippi River near Winfield, Mo. Illinois River at Hardin, Ill. Missouri River at Hermann, Mo.
phenol 18 ND 33
benzene, 1,3-dichloro- ND ND 1.8
benzene, 1,4-dichloro- ND ND 0.32
benzene, 1,2-dichloro- ND ND 0.25
nitrobenzene ND ND ND
benzene, 1,2,4-trichloro- ND ND ND
naphthalene 7.2 2.3 2.8
acenaphthylene 7.6 20 0.31
dimethylphthalate 40 16 10
acenaphthene 2.8 2.4 0.88
toluene, 2,4-dinitro- ND ND ND
fluorene 9.9 4.7 1.2
diethylphthalate 200 80 60
hexachlorobenzene ND ND ND
phenanthrene 58 29 12
anthracene 7.6 6 0.67
di-n-butylphthalate 760 630 290
fluoranthene 43 66 11
pyrene 36 78 8.3
butylbenzylphthalate 510 260 53
benz(a)anthracene 10 28 3.8
chrysene 21 44 7.5
bis(2-ethylhexyl)phthalate 1,500 660 1,100
di-n-octylphthalate ND ND 4.2
benzo(b)fluoranthene 23 65 6
benzo(k)fluoranthene 14 39 5
benzo(a)pyrene 20 25 39
indeno(1,2,3-cd)pyrene 28 60 11
dibenz(a,h)anthracene ND 14 ND
benzo(g,h,i)perylene 25 56 ND
      Sampling site
Mississippi River at St. Louis, Mo. Mississippi River at Thebes, Ill. Ohio River at Olmsted, Ill.
phenol 38 33 39
benzene, 1,3-dichloro- 2.6 4 3.6
benzene, 1,4-dichloro- 0.51 0.74 1.1
benzene, 1,2-dichloro- 0.44 0.62 0.93
nitrobenzene 0.43 0.96 ND
benzene, 1,2,4-trichloro- ND ND 4
naphthalene 8.4 6.2 33
acenaphthylene 5.2 6.7 13
dimethylphthalate 28 17 29
acenaphthene 2.5 3 6.2
toluene, 2,4-dinitro- ND ND ND
fluorene 5.4 6.3 13
diethylphthalate 160 96 120
hexachlorobenzene ND ND 2
phenanthrene 53 41 124
anthracene 6.8 6 120
di-n-butylphthalate 370 320 400
fluoranthene 46 62 97
pyrene 42 60 76
butylbenzylphthalate 170 110 390
benz(a)anthracene 22 37 46
chrysene 40 51 89
bis(2-ethylhexyl)phthalate 2,000 770 1,400
di-n-octylphthalate 34 ND ND
benzo(b)fluoranthene 63 85 190
benzo(k)fluoranthene 40 36 97
benzo(a)pyrene 19 27 22
indeno(1,2,3-cd)pyrene 45 45 170
dibenz(a,h)anthracene 8.4 8.9 50
benzo(g,h,i)perylene 44 41 180
      Sampling site
Mississippi River below Hickman, Ky. Mississippi River at Fulton, Tenn. Mississippi River at Helena, Ark.
phenol 18 45 0.95
benzene, 1,3-dichloro- 2.5 3.2 3.7
benzene, 1,4-dichloro- 0.47 0.76 1
benzene, 1,2-dichloro- 0.43 0.62 0.94
nitrobenzene ND ND ND
benzene, 1,2,4-trichloro- 0.94 1.8 1.8
naphthalene 8.7 16 20
acenaphthylene 13 7.3 3.9
dimethylphthalate 38 38 27
acenaphthene 5.5 2.1 ND
toluene, 2,4-dinitro- ND ND ND
fluorene 11 5.6 6.1
diethylphthalate 200 190 140
hexachlorobenzene ND 0.78 0.69
phenanthrene 98 59 48
anthracene 16 8.2 4.4
di-n-butylphthalate 220 200 130
fluoranthene 98 67 50
pyrene 97 58 40
butylbenzylphthalate 210 180 95
benz(a)anthracene 50 29 26
chrysene 69 50 46
bis(2-ethylhexyl)phthalate 410 810 570
di-n-octylphthalate ND ND 12
benzo(b)fluoranthene 120 88 200
benzo(k)fluoranthene 38 53 8.7
benzo(a)pyrene 48 14 13
indeno(1,2,3-cd)pyrene 64 63 86
dibenz(a,h)anthracene 12 10 17
benzo(g,h,i)perylene 59 59 79
      Sampling site
White River at Mile 11.5, Ark. Arkansas River at Pendleton, Ark. Mississippi River above Arkansas City, Ark.
phenol 34 39 120
benzene, 1,3-dichloro- 2 4.9 0.99
benzene, 1,4-dichloro- 0.28 0.75 0.85
benzene, 1,2-dichloro- 0.3 0.79 1.3
nitrobenzene ND ND ND
benzene, 1,2,4-trichloro- ND ND 2.4
naphthalene 4 7.4 25
acenaphthylene 0.19 0.97 9.4
dimethylphthalate 61 42 23
acenaphthene ND ND 4.1
toluene, 2,4-dinitro- ND ND ND
fluorene 2.2 5 8.6
diethylphthalate 34 220 120
hexachlorobenzene ND ND 0.87
phenanthrene 23 31 61
anthracene 0.28 1.9 11
di-n-butylphthalate 290 220 110
fluoranthene 6.6 19 60
pyrene 3.4 16 53
butylbenzylphthalate 180 130 200
benz(a)anthracene 1.5 11 32
chrysene 3.6 22 56
bis(2-ethylhexyl)phthalate 1,200 5,800 5,400
di-n-octylphthalate 42 ND ND
benzo(b)fluoranthene 1.9 19 80
benzo(k)fluoranthene 1.7 11 57
benzo(a)pyrene ND 6.6 29
indeno(1,2,3-cd)pyrene ND 8.7 90
dibenz(a,h)anthracene ND ND 15
benzo(g,h,i)perylene ND 14 88
      Sampling site
Yazoo River below Steele Bayou, Miss. Mississippi River below Vicksburg, Miss. OutflowChannel near Knox Landing, La.
phenol 56 15 150
benzene, 1,3-dichloro- 0.93 1.2 1.6
benzene, 1,4-dichloro- 0.93 0.16 1.1
benzene, 1,2-dichloro- 0.74 0.21 1.3
nitrobenzene ND ND ND
benzene, 1,2,4-trichloro- ND 0.7 2.1
naphthalene 3.4 6.7 22
acenaphthylene 0.22 2.1 10
dimethylphthalate 17 8.6 13
acenaphthene ND 0.72 3.5
toluene, 2,4-dinitro- ND ND ND
fluorene 0.8 2.4 3.5
diethylphthalate 91 44 29
hexachlorobenzene ND 0.34 ND
phenanthrene 7 25 55
anthracene 0.35 3 7
di-n-butylphthalate 120 48 85
fluoranthene 5 30 45
pyrene 3.2 27 40
butylbenzylphthalate 72 41 110
benz(a)anthracene 0.72 14 22
chrysene 2.7 19 46
bis(2-ethylhexyl)phthalate 150 1,800 650
di-n-octylphthalate 3 ND 11
benzo(b)fluoranthene 4.4 11 120
benzo(k)fluoranthene 1.7 15 69
benzo(a)pyrene 5.8 4.3 14
indeno(1,2,3-cd)pyrene ND 14 110
dibenz(a,h)anthracene ND ND 24
benzo(g,h,i)perylene ND 12 120
      Sampling site            
Mississippi River near St. Francisville, La. Mississippi River belowBelle Chasse, La. Procedure blank Procedure blank
phenol 44 33 5.3 10
benzene, 1,3-dichloro- 2.3 2.4 0.82 0.77
benzene, 1,4-dichloro- 1.4 0.4 0.14 0.12
benzene, 1,2-dichloro- 1.1 0.4 0.15 0.15
nitrobenzene ND ND ND ND
benzene, 1,2,4-trichloro- 2 1.1 ND ND
naphthalene 17 8.5 0.55 0.5
acenaphthylene 3.4 6.9 ND ND
dimethylphthalate 27 33 1.5 1.6
acenaphthene 3 3.3 ND ND
toluene, 2,4-dinitro- 1.3 ND ND ND
fluorene 5 5.6 ND ND
diethylphthalate ND 190 4.1 3.8
hexachlorobenzene 0.76 2.7 ND ND
phenanthrene 50 57 0.38 0.35
anthracene 4.1 8.4 ND ND
di-n-butylphthalate 120 210 23 25
fluoranthene 48 59 0.29 0.2
pyrene 40 51 ND ND
butylbenzylphthalate 110 220 0.98 ND
benz(a)anthracene 21 29 ND ND
chrysene 33 47 ND ND
bis(2-ethylhexyl)phthalate 320 2,300 11,200 15,000
di-n-octylphthalate ND ND 570 290
benzo(b)fluoranthene 110 80 ND ND
benzo(k)fluoranthene 59 32 ND ND
benzo(a)pyrene 19 21 ND ND
indeno(1,2,3-cd)pyrene 70 49 ND ND
dibenz(a,h)anthracene 17 12 ND ND
benzo(g,h,i)perylene 72 51 ND ND

Table 13. Hydrophobic U.S. Environmental Protection Agency priority pollutants detected in suspended-sediment samples collected during the February-March 1990 cruise.

[All concentrations in micrograms per kilogram dry sediment; ND, not detected]

      Sampling site
Compound Ohio River at Olmsted, Ill. Mississippi River below Hickman, Ky. Mississippi River below Fulton, Tenn.
phenol 53 44 44
benzene, 1,3-dichloro- 0.5 0.5 ND
benzene, 1,4-dichloro- 5.3 3.3 2
benzene, 1,2-dichloro- 2.5 1.1 0.54
nitrobenzene ND ND ND
benzene, 1,2,4-trichloro- 17 9.7 4.4
naphthalene 47 29 23
acenaphthylene 7.8 29 18
dimethylphthalate 7 8 6.4
acenaphthene 13 9.3 6.9
toluene, 2,4-dinitro- ND ND ND
fluorene 19 16 12
diethylphthalate 5.9 6.9 6.8
hexachlorobenzene 3.6 2.6 2.8
phenanthrene 160 120 92
anthracene 27 38 26
di-n-butylphthalate 31 23 88
fluoranthene 200 200 150
pyrene 180 180 140
butylbenzylphthalate 41 70 45
benz(a)anthracene 130 98 72
chrysene 180 140 100
bis(2-ethylhexyl)phthalate 730 1,000 670
di-n-octylphthalate ND ND ND
benzo(b)fluoranthene 210 160 130
benzo(k)fluoranthene 100 100 75
benzo(a)pyrene 100 89 65
indeno(1,2,3-cd)pyrene 130 130 100
dibenz(a,h)anthracene 34 22 16
benzo(g,h,i)perylene 110 120 90
      Sampling site
Mississippi River at Helena, Ark. Mississippi River above Arkansas City, Ark. Mississippi River below Vicksburg, Miss.
phenol 62 15 15
benzene, 1,3-dichloro- 0.71 0.23 0.26
benzene, 1,4-dichloro- 2.9 1.3 1.7
benzene, 1,2-dichloro- 2 0.42 0.62
nitrobenzene ND ND ND
benzene, 1,2,4-trichloro- 7.5 3.9 4.1
naphthalene 20 16 15
acenaphthylene 20 14 13
dimethylphthalate 8.6 6.6 7.5
acenaphthene 6.4 4.2 5.4
toluene, 2,4-dinitro- ND ND ND
fluorene 11 9.6 9.2
diethylphthalate 8.7 5.4 7.4
hexachlorobenzene 0.88 1.3 ND
phenanthrene 89 72 63
anthracene 26 17 16
di-n-butylphthalate 33 18 21
fluoranthene 110 100 100
pyrene 96 87 96
butylbenzylphthalate 220 59 47
benz(a)anthracene 73 66 48
chrysene 110 87 70
bis(2-ethylhexyl)phthalate 11,200 820 560
di-n-octylphthalate 270 ND ND
benzo(b)fluoranthene 110 90 110
benzo(k)fluoranthene 53 74 65
benzo(a)pyrene 57 42 44
indeno(1,2,3-cd)pyrene 110 76 65
dibenz(a,h)anthracene 21 13 ND
benzo(g,h,i)perylene 110 72 61
      Sampling site
Mississippi River near St. Francisville, La. Mississippi River below Belle Chasse, La.      
phenol ND 11      
benzene, 1,3-dichloro- 0.28 0.3      
benzene, 1,4-dichloro- 2.1 0.5      
benzene, 1,2-dichloro- 0.67 0.38      
nitrobenzene ND ND      
benzene, 1,2,4-trichloro- 3.8 2.6      
naphthalene 18 11      
acenaphthylene 14 8.3      
dimethylphthalate 17 13      
acenaphthene 4 ND      
toluene, 2,4-dinitro- ND ND      
fluorene 7.3 7      
diethylphthalate 14 14      
hexachlorobenzene ND 1.6      
phenanthrene 51 48      
anthracene 14 14      
di-n-butylphthalate 26 30      
fluoranthene 89 61      
pyrene 84 54      
butylbenzylphthalate 74 70      
benz(a)anthracene 39 38      
chrysene 58 53      
bis(2-ethylhexyl)phthalate 780 520      
di-n-octylphthalate ND ND      
benzo(b)fluoranthene 70 50      
benzo(k)fluoranthene 48 37      
benzo(a)pyrene 23 49      
indeno(1,2,3-cd)pyrene 83 47      
dibenz(a,h)anthracene 22 8.7      
benzo(g,h,i)perylene 79 47      

Hexachlorobenzene was targeted by both the halogenated organic compound analysis (by GC/NCI/MS) and the priority pollutant analysis (by GC/EI/MS). The detection limit for the priority pollutant technique was higher than the halogenated technique, and varied with sample size. For samples with data by both techniques, the values in microgram/kg were compared. The GC/NCI/MS values were consistently slightly higher, but the variation of the values from the two techniques averaged about 15 percent of their mean.

The semiquantitative data for organochlorine compounds and herbicides are presented in table 14 for June 1989 and table 15 for February-March 1990. Recoveries of these polar compounds, using the extraction and fractionation technique that targeted isolation of hydrophobic organic compounds, are unknown.

Table 14. Semiquantitative screening for organochlorine compounds and herbicides found in suspended-sediment samples collected during the June 1989 cruise.

[All concentrations in micrograms per kilogram dry sediment; ND, not detected]

      Sampling site
Mississippi River near Winfield, Mo. Illinois River at Hardin, Ill. Missouri River at Hermann, Mo.
Organochlorine compounds
Pentachloronitrobenzene ND ND ND
DDE 12 8.7 0.98
DDD 7.3 4.3 2.5
DDT 13 22 1.1
Herbicides
Trifluralin 0.34 0.81 0.39
Atrazine ND 1.6 0.6
Alachlor 10 9.5 3.2
Metolachlor 2.3 0.22 2.9
Carbamate
Eptan (EPTC) ND ND 2.7
     
      Sampling site
      Mississippi River at St. Louis, Mo. Mississippi River at Thebes, Ill. Ohio River at Olmsted, Ill.
Pentachloronitrobenzene ND ND ND
DDE ND 2.2 5
DDD ND 3.4 10
DDT ND 1 40
Herbicides
Trifluralin 0.17 ND 7
Atrazine 0.88 ND 1.4
Alachlor 4.8 2.8 420
Metolachlor 1 0.74 34
Carbamate
Eptan (EPTC) ND ND ND
      Sampling site
Mississippi River below Hickman, Ky. Mississippi River at Fulton, Tenn. Mississippi River at Helena, Ark.
Pentachloronitrobenzene ND ND ND
DDE ND 2.4 6.2
DDD ND 5.9 17
DDT ND 1.4 46
Herbicides
Trifluralin ND 0.94 0.73
Atrazine 6 ND ND
Alachlor 30 12 13
Metolachlor 3.1 1.5 3.7
Carbamate
Eptan (EPTC) ND ND ND
      Sampling site
      White River at Mile 11.5, Ark. Arkansas River at Pendleton, Ark. Mississippi River above Arkansas City, Ark.
Organochlorine compounds
Pentachloronitrobenzene ND ND ND
DDE 7.9 4 2.2
DDD 9.1 2.8 16
DDT 6.3 0.98 17
Herbicides
Trifluralin 0.14 ND 0.79
Atrazine ND ND ND
Alachlor ND ND 10
Metolachlor ND ND 3.4
Carbamate
Eptan (EPTC) ND ND ND
      Sampling site
      Yazoo River below Steele Bayou, Miss. Mississippi River below Vicksburg, Miss. OutflowChannel near Knox Landing, La.
Organochlorine compounds
Pentachloronitrobenzene 0.97 ND ND
DDE 18 1.8 16
DDD 55 5.1 79
DDT 100 0.38 23
Herbicides
Trifluralin 0.39 0.11 1.2
Atrazine 1.1 ND ND
Alachlor ND 1.5 18
Metolachlor 0.94 0.36 3.7
      Sampling site
Yazoo River below Steele Bayou, Miss. Mississippi River below Vicksburg, Miss. OutflowChannel near Knox Landing, La.
Carbamate
Eptan (EPTC) ND ND ND

      Sampling site            
      Mississippi River near St. Francisville, La. Mississippi River below Belle Chasse, La. Procedure blank Procedure blank
Organochlorine compounds
Pentachloronitrobenzene ND ND ND ND
DDE 16 4.6 ND ND
DDD 34 13 ND ND
DDT 16 9.9 ND ND
Herbicides
Trifluralin 0.84 0.22 ND ND
Atrazine 0.31 ND ND ND
Alachlor 9 2.7 ND ND
Metolachlor 2 0.89 ND ND
Carbamate
Eptan (EPTC) ND ND ND ND

Table 15. Semiquantitative screening for organochlorine compounds and herbicides found in suspended-sediment samples collected during the February-March 1990 cruise.

[All concentrations in micrograms per kilogram dry sediment; ND, not detected]

      Sampling site
Ohio River at Olmsted, Ill. Mississippi River below Hickman, Ky. Mississippi River below Fulton, Tenn.
Organochlorine compounds
Pentachloronitrobenzene ND ND ND
DDE ND 11 ND
DDD ND 7.8 ND
DDT 16 40 ND
Herbicides
Trifluralin 1.9 0.96 1.1
Atrazine 3.1 ND 2.7
Alachlor ND 4.3 5.2
Metolachlor ND 1.5 ND
Carbamate
Eptan (EPTC) ND ND ND
      Sampling site
      Mississippi River at Helena, Ark. Mississippi River above Arkansas City, Ark. Mississippi River below Vicksburg, Miss.
Organochlorine compounds
Pentachloronitrobenzene ND ND ND
DDE ND 3.4 18
DDD ND 5.7 41
DDT ND 18 13
Herbicides
Trifluralin 0.89 0.91 0.85
Atrazine ND 1.2 ND
Alachlor 2.8 2.9 2.6
Metolachlor ND 1.2 ND
Carbamate
Eptan (EPTC) ND ND ND
      Sampling site
Mississippi River near St. Francisville, La. Mississippi River below Belle Chasse, La.      
Organochlorine compounds
Pentachloronitrobenzene ND ND      
DDE 24 14      
DDD 57 44      
DDT 21 9.3      
Herbicides
Trifluralin 0.69 0.55      
Atrazine ND 1.6      
Alachlor 2.5 2      
Metolachlor ND 0.72      
Carbamate
Eptan (EPTC) ND ND      

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