In cooperation with the City of Fort Worth

Particle-Associated Contaminants in Street 

Dust, Parking Lot Dust, Soil, Lake-Bottom 

Sediment, and Suspended and Streambed 

Sediment, Lake Como and Fosdic Lake 

Watersheds, Fort Worth, Texas, 2004

Data Series 211

U.S. Department of the Interior

U.S. Geological Survey
Blank Page
Particle-Associated Contaminants in Street 

Dust, Parking Lot Dust, Soil, Lake-Bottom 

Sediment, and Suspended and Streambed 

Sediment, Lake Como and Fosdic Lake 

Watersheds, Fort Worth, Texas, 2004 

By Jennifer T. Wilson, Peter C. Van Metre, Charles J. Werth, and Yanning Yang 

U.S. Department of the Interior

U.S. Geological Survey

In cooperation with the City of Fort Worth

Data Series 211
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

U.S. Geological Survey, Reston, Virginia: 2006

For sale by U.S. Geological Survey, Information Services

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply

endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to

reproduce any copyrighted materials contained within this report.

Suggested citation:

Wilson, J.T., Van Metre, P.C., Werth, C.J., and Yang, Yanning, 2006, Particle-associated contaminants in street dust,

parking lot dust, soil, lake-bottom sediment, and suspended and streambed sediment, Lake Como and Fosdic Lake

watersheds, Fort Worth, Texas, 2004: U.S. Geological Survey Data Series 211, 24 p.
iii

Contents

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Study Design and Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Analytical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Organic Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Major and Trace Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Organic Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Radionuclides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Particle-Associated Contaminants in Street Dust, Parking Lot Dust, Soil, Lake-Bottom Sediment, 

and Suspended and Streambed Sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figures

1–2. Maps showing: 

1. Sites where samples of street dust, parking lot dust, soil, lake-bottom sediment, 

and suspended and streambed sediment were collected in Lake Como watershed, 

October 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2. Sites where samples of street dust, parking lot dust, soil, lake-bottom sediment, 

and suspended and streambed sediment were collected in Fosdic Lake watershed, 

October 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Tables

1. Selected chlorinated hydrocarbon compound concentrations in street dust, parking lot 

dust, soil, lake-bottom sediment, and suspended and streambed sediment samples 

collected in Lake Como and Fosdic Lake watersheds, October 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, 

soil, lake-bottom sediment, and suspended and streambed sediment samples collected

in Lake Como and Fosdic Lake watersheds, October 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3. Major and trace element concentrations street dust, parking lot dust, soil, lake-bottom 

sediment, and suspended and streambed sediment samples collected in Lake Como and 

Fosdic Lake watersheds, October 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4. Organic carbon concentrations in street dust, parking lot dust, soil, and lake-bottom 

sediment samples collected in Lake Como and Fosdic Lake watersheds, October 2004 . . . . . . . . . . . 23

5. Grain-size distribution in lake-bottom and streambed sediment samples collected in Lake 

Como and Fosdic Lake watersheds, October 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6. Radionuclide activities in lake-bottom sediment samples collected in Lake Como and 

Fosdic Lake watersheds, October 2004 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Blank Page
Particle-Associated Contaminants in Street 

Dust, Parking Lot Dust, Soil, Lake-Bottom 

Sediment, and Suspended and Streambed 

Sediment, Lake Como and Fosdic Lake 

Watersheds, Fort Worth, Texas, 2004 

By Jennifer T. Wilson1, Peter C. Van Metre1, Charles J. Werth2, and Yanning Yang2

Abstract

A previous study of impaired water bodies in Fort Worth, 

Texas, by the U.S. Geological Survey, reported elevated but 

variable concentrations of particle-associated contaminants 

(PACs) comprising chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, and trace elements in suspended and bed 

sediment of lakes and streams affected by urban land use. The 

U.S. Geological Survey, in cooperation with the City of Fort 

Worth, collected additional samples during October 2004 to 

investigate sources of PACs in the watersheds of two impaired 

lakes: Lake Como and Fosdic Lake. Source materials and 

aquatic sediment were sampled and analyzed for PACs. Source 

materials sampled consisted of street dust and soil from areas 

with residential and commercial land use and parking lot dust 

from sealed and unsealed parking lots. Aquatic sediment sampled consisted of bottom-sediment cores from the two lakes and 

suspended and streambed sediment from the influent stream of 

each lake. Samples were analyzed for chlorinated hydrocarbons 

(organochlorine pesticides and polychlorinated biphenyls), 

polycyclic aromatic hydrocarbons, major and trace elements, 

organic carbon, grain size, and radionuclides.

Introduction

Particle-associated contaminants (PACs) are an important 

component of urban nonpoint-source pollution to aquatic 

systems. PACs, which include chlorinated hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and trace elements, pose 

a threat to aquatic biota and humans because many are persistent, bioaccumulative, or toxic (U.S. Environmental Protection 

Agency, 1997). Occurrence of PACs has resulted in the impairment of thousands of streams, lakes, and reservoirs. PACs were 

responsible for fish-consumption advisories for 35 percent of 

total lake acreage and 24 percent of total river mileage in the 

United States in 2004 (U.S. Environmental Protection Agency, 

2005), and PACs comprise more than 20 percent of total maximum daily loads (TMDLs) nationwide (U.S. Environmental 

Protection Agency, 2006). Lakes and streams in Fort Worth, 

Tex., are among these impaired water bodies: Lake Como, Echo 

Lake, Fosdic Lake, and segments of the West Fork Trinity River 

and Clear Fork Trinity River are under fishing advisories or fish 

consumption bans and are included in part of a study of TMDLs 

for legacy pollutants (Van Metre and others, 2003). A “legacy 

pollutant” is a constituent once widely used for certain applications but now banned or withdrawn from such use.

The U.S. Geological Survey (USGS) studied the occurrence of and trends in PACs in several Fort Worth water bodies 

(Van Metre and others, 2003) and found relatively high concentrations of chlorinated hydrocarbons, PAHs, and trace elements 

in the more urban sites. The USGS also found that legacy pollutants and PAHs were not uniformly preserved in bottom sediment in the lakes as they were in suspended sediment in 

streams (Van Metre and Mahler, 2004). 

Higher concentrations of some organic pollutants in 

streams relative to the downstream reservoirs raises several 

questions, including: Are some contaminant concentrations in 

street dust and soil much higher than indicated by measurements in aquatic sediment? One potential PAH contaminant 

source of particular interest is parking lot sealcoat, the black, 

shiny substance sprayed or painted on the surfaces of parking 

lots and driveways to protect the underlying asphalt and to 

enhance appearance. A recent study of PAH sources to urban 

water bodies (Mahler and others, 2005), found that sealcoats 

have extremely high concentrations of PAHs and that sealcoats 

could account for the majority of PAHs in the streams studied. 

1 U.S. Geological Survey.

2 University of Illinois Urbana-Champaign.
2 Particle-Associated Contaminants, Lake Como and Fosdic Lake Watersheds, Fort Worth, Texas, 2004

Those streams included the inflows to Lake Como and Fosdic 

Lake in Fort Worth. 

This report, prepared by the USGS in cooperation with the 

City of Fort Worth and in collaboration with the University of 

Illinois, documents measured concentrations of PACs in various source materials and aquatic sediment in the Lake Como 

and Fosdic Lake watersheds (figs. 1 and 2). Source materials 

consisted of street dust, parking lot dust, and soil. Aquatic sediment consisted of bottom-sediment cores from the two lakes 

and suspended and streambed sediment from the influent 

stream to each lake.

Approach 

Study Design and Sampling

Samples of source materials and aquatic sediment from the 

watersheds of Lake Como and Fosdic Lake were collected and 

analyzed for PACs. Samples of residential street dust, parking 

lot dust from sealed and unsealed commercial parking lots, 

commercial soil, residential soil, lake-bottom sediment (core), 

and suspended and streambed sediment were collected from 

each watershed. Sampling of street and parking lot dust, soil, 

and lake-bottom sediment was done during October 20–21, 

2004. The street and parking lot dust and soil samples were 

composed of material expected to wash off (street and parking 

lot dust) or deemed most likely to erode (soil) in the next rain 

storm. Sampling of suspended sediment was done during a 

storm on October 22, 2004. Sampling of streambed sediment 

was completed after the stormflow receded on October 25, 

2004. 

Street and parking lot dust samples were collected by 

sweeping with clean, nylon push brooms and dust pans. Parking 

lot samples were a composite sample from three commercial 

parking lots of each surface type, sealed or unsealed. Residential asphalt street dust samples were a composite of sweepings 

from three blocks of residential roadway in each watershed 

(figs. 1 and 2). These samples were sieved using a 1-millimeter 

sieve, homogenized, and split for chemical analyses. Samples 

for analyses of organic compounds were stored chilled pending 

analysis. 

Each soil sample was a composite of material scraped from 

an exposed area of soil (scraped to about 1-centimeter deep or 

less) within a few meters of the street. About 40 locations distributed randomly over a several-block commercial or residential area were sampled to form each composite sample (figs. 1 

and 2). About 4 liters of material were collected, air-dried under 

a hood, broken up, and passed through a 1-millimeter sieve. The 

material that passed the sieve was homogenized and split for 

chemical analyses. 

Bottom-sediment core samples from the lakes were collected using a 14- by 14-centimeter-square, 50-centimeter-tall 

box corer following the sampling methods of Van Metre and 

others (2004). Four cores were collected from a single site in 

each lake (figs. 1 and 2), corresponding to the lower lake site in 

Lake Como and mid-lake site in Fosdic Lake reported by Van 

Metre and others (2003). The cores were sliced at 5-centimeter 

intervals by vertical extrusion, and segments from corresponding depth intervals from the four cores were combined to form 

six composite samples to a depth of 30 centimeters. Samples 

were homogenized, split, and stored chilled. 

Suspended sediment samples were obtained during a storm 

that caused runoff on October 22, 2004, the day after street and 

parking lot dust, soil, and lake-bottom sediment sampling was 

completed. Samples were collected by filling three 25-liter 

polycarbonate containers with water during storm runoff and 

then filtering the samples at the USGS Texas Water Science 

Center (WSC) in Fort Worth to isolate the sediment following 

the method of Mahler and Van Metre (2003). Samples were 

collected at the same site on each influent stream that was 

monitored for suspended-sediment chemistry and loads by 

Van Metre and others (2003). The 25-liter containers were 

filled by submerging them in the center of the small (1- to 2-

meter wide) channel of each stream (figs. 1 and 2). Sediment for 

elemental analyses was isolated by filtration using 0.45-

micrometer Teflon filters held in 140-millimeter-diameter 

acrylic filter holders. Sediment for organic-compound analyses 

was isolated by filtration using 0.45-micrometer Teflon filters 

held in 293-millimeter-diameter stainless steel filter holders. 

Two organic-compound filters (reused twice each) and eight 

elemental-analyses filters were used for the Lake Como inflow 

sample. Three organic-compound filters (reused twice each) 

and five elemental-analyses filters were used to isolate sediment from the Fosdic Lake inflow sample. For both lakes, all 

75 liters were filtered. 

Streambed sediment samples were collected 3 days after 

the storm, on October 25, 2004, from pools in the influent 

streams to the two lakes near the locations where suspended 

sediment samples were collected (figs. 1 and 2). Samples 

were collected from areas of the channel where fine-grained 

sediment tends to accumulate by scooping the soft, relatively 

fine-grained sediment with a 125-milliliter baked glass sampling jar. Numerous scoops were combined in 4-liter baked 

glass sampling jars (total of 6.5 liters from Lake Como inflow 

channel and 9 liters from Fosdic Lake inflow channel). The wet 

material was chilled and sieved using a 1-millimeter mesh sieve 

at the USGS Texas WSC in Austin. The material that passed the 

sieve was homogenized and split into subsamples for chemical 

analyses.

Analytical

Analyses included chlorinated hydrocarbons (organochlorine pesticides and polychlorinated biphenyls [PCBs]), 

PAHs, and major and trace elements. Selected samples were 

analyzed for organic carbon, grain size, and radionuclides. 

Samples for analysis of organic compounds were chilled and 

shipped wet to the USGS National Water Quality Laboratory 
Figure 1. Sites where samples of street dust, parking lot dust, soil, lake-bottom sediment, and suspended and streambed sediment were collected in 

October 2004. 
4 Particle-Associated Contaminants, Lake Como and Fosdic Lake Watersheds, Fort Worth, Texas, 2004

Figure 2. Sites where samples of street dust, parking lot dust, soil, lake-bottom sediment, and suspended and streambed sediment were 

collected in Fosdic Lake watershed, October 2004.
Approach 5

(NWQL) in Denver, Colo. Samples for analyses of major and 

trace elements, forms of carbon, and radionuclides were freezedried and ground to a fine powder at the USGS Texas WSC in 

Austin, prior to analyses by the USGS Geology Discipline Mineral Resources Team Laboratory in Denver, Colo. Samples for 

analysis of organic carbon were chilled and shipped wet to the 

laboratory of the University of Illinois Urbana-Champaign, in 

Urbana, Ill. Samples for analysis of grain size were chilled and 

shipped wet to the USGS Iowa WSC sediment laboratory in 

Iowa City. The Iowa sediment laboratory did the grain-size 

analyses of lake-bottom and streambed sediment samples using 

sieve and pipet methods (Guy, 1969). Brief descriptions of the 

other analytical procedures follow.

Organic Compounds

Organochlorine pesticides, PCBs, PAHs, and alkylsubstituted PAHs (alkyl-PAHs) were extracted, isolated, and 

analyzed using the procedures of Noriega and others (2003) and 

Olson and others (2003). Briefly, wet lake-bottom sediment and 

streambed sediment were extracted overnight with dichloromethane in a Soxhlet apparatus. The extract was reduced in 

volume and filtered. Two aliquots of the sample extract were 

quantitatively injected into a polystyrene-divinylbenzene gel 

permeation column and eluted with dichloromethane to remove 

sulfur and partially isolate the target analytes. The first aliquot 

was analyzed for PAHs and alkyl-PAHs by capillary-column 

gas chromatography with detection by full-scan mass spectrometry (MS) or by selected ion monitoring MS. Eighteen parent 

PAHs, nine specific alkyl-PAHs, and the homologous series of 

alkyl-PAHs for 2- to 5-ringed PAH were determined. 

The second aliquot was split into two sample fractions by 

combined alumina/silica adsorption chromatography, followed 

by Florisil adsorption chromatography for further cleanup of 

the second fraction. Both fractions were analyzed by dual capillary-column gas chromatography with electron capture detection (GC-ECD) for the determination of the organochlorine pesticides and PCBs. Organochlorine pesticides were reported as 

individual compounds, and PCBs were reported as individual 

Aroclor (1016/1242, 1254, or 1260) equivalents. 

The PCB fraction of the organic compound analysis was 

analyzed for 27 (of 209 possible) selected PCB congeners along 

with the other analytes during GC-ECD analysis. The congeners chosen for this analysis were some of the more dominant 

congeners in the most widely used Aroclors (1016, 1242, 1254, 

and 1260). In addition to the dominance of these congeners, 

potential coelution issues and signal response for this analytical 

method were considered. A series of dilutions of a custom mixture containing the 27 selected PCB congeners was used to 

make the calibration standards. Calibration standards were prepared at four concentrations, and a minimum of three points 

were used for the calibration curves. An additional congener 

solution, prepared at a concentration that was mid-range on the 

curve, was used as a check standard to verify the calibration 

curve.

Quality assurance for organic compound analyses was provided by analyzing an environmental duplicate sample, a blank 

sample, and a spiked sample and by monitoring recovery of surrogate compounds with each set of 12 environmental samples. 

Van Metre and others (2004) reported that the median relative 

percent differences using these methods for chlorinated hydrocarbons was 11.8 percent for 41 duplicate samples and for 

PAHs was 11.9 percent for 40 samples.

Major and Trace Elements

Elemental concentrations were determined on concentrated-acid (hydrochloric-nitric-perchloric-hydrofloric) digests 

(“total” digestions) by inductively coupled plasma/mass spectrometry at the Mineral Resources Team laboratory in Denver 

(Briggs and Meier, 2003). Concentrations of mercury were 

determined by cold-vapor atomic adsorption spectroscopy 

(Brown and others, 2003). Total carbon was measured by combustion with an automatic carbon analyzer, inorganic carbon 

was measured as carbon dioxide by coulometric titration, and 

organic carbon was computed by difference (Arbogast, 1996). 

Quality assurance was provided by analyzing several standard 

reference materials, sample replicates, and a blank sample with 

each batch of as many as 20 samples. 

Organic Carbon

Percent organic carbon was determined for selected sediment samples at the University of Illinois Urbana-Champaign 

laboratory. Sediment was air-dried, ground, and passed through 

a 200-mesh (75-micrometer) sieve. Inorganic carbon was 

removed with a 4-normal (N) hydrochloric acid (HCl) treatment, followed by 22-N hydrofluoric acid (HF) and 6-N HCl 

treatments to remove silicate minerals (Durand and Nicaise, 

1980). Easily extracted organic matter such as polysaccharides 

and other hydrolyzable organic matter was removed by treatment with trifluoroacetic acid (Gelinas and others, 2001). 

Humic and fulvic acids then were extracted from the sample 

(Swift, 1996). Humic acid was extracted using 0.1-molar 

sodium hydroxide (NaOH) and precipitated by neutralization 

using 6-molar HCl. Fulvic acid, which is not precipitated with 

6-molar HCl, was separated by passing through a column of 

XAD-8 (acrylic ester composition). At this point, the remaining 

carbon material was enriched in kerogen and black carbon. 

Kerogen was removed by heat treatment leaving only black carbon. After each treatment step, total organic carbon was analyzed using a carbon dioxide coulometer and thermal combustion at 950 degrees Celsius (Li and Werth, 2001). 

Radionuclides 

Selected samples from the two lake-bottom sediment cores 

were analyzed for lead-210 (210Pb), radium-226 (226Ra), and 
6 Particle-Associated Contaminants, Lake Como and Fosdic Lake Watersheds, Fort Worth, Texas, 2004

cesium-137 (137Cs) at a USGS laboratory in Menlo Park, Calif. 

Activities of total 210Pb, 226Ra, and 137Cs were measured 

simultaneously by gamma spectrometry on the basis of 

American Society for Testing and Materials (ASTM) methods 

C 1402–98 and E 181–98. The analytical method used for 

the samples in this study is similar to methods described by 

Robbins and Edgington (1975), Baskaran and Naidu (1994), 

and Fuller and others (1999). Subsamples of dried sediment 

samples were counted for radionuclide activity using a highresolution intrinsic germanium detector gamma spectrometer. 

The supported 210Pb activity, defined by the 226Ra activity, was 

determined on each sample from the 352 and 609 kiloelectronvolt gamma emission lines of lead-214 and bismuth-214 (the 

short-lived daughters of 226Ra), respectively. Self-absorption of 

the gamma emission line for each isotope was accounted for 

using an attenuation factor for each counting container calculated from an empirical relation between self-absorption and 

bulk density developed for this geometry on the basis of the 

method of Cutshall and others (1983). Detector efficiency for 

each isotope was determined from National Institute of Standards and Technology traceable standards. National Institute of 

Standards and Technology and International Atomic Energy 

Agency reference materials were counted monthly to check 

detector calibration. The reported uncertainty in the measured 

activity was calculated from the random counting error of samples, and background spectra at the one standard deviation level 

was typically within ±10 percent. The measured activities of 

replicate analysis of material from the same sample agreed to 

within 15 percent. 

Particle-Associated Contaminants in Street 

Dust, Parking Lot Dust, Soil, Lake-Bottom 

Sediment, and Suspended and Streambed 

Sediment

Results of selected physical and chemical analyses 

(detected constituents only) are presented in tables 1–6 (at end 

of report). Analyses were not completed for samples collected 

from parking lots in the Fosdic Lake watershed because sample 

jars were broken during shipment to the laboratory. Total DDT 

was computed as the sum of the detected and estimated (identified with an “E” before the concentration) concentrations of 

p,p’-DDD, p,p’-DDE, and p,p’-DDT. Technical chlordane was 

computed as 1.6 times the sum of the detected and estimated 

concentrations of cis-chlordane, trans-chlordane, and transnonachlor (Dennis Markovich, U.S. Geological Survey 

National Water Quality Laboratory, written commun., 2006). 

The sum of the PCB Aroclors was computed as the sum of 

the detected and estimated concentrations of PCB Aroclors 

1016/1242, 1254, and 1260. The sum of the PCB congeners was 

computed as the sum of the detected and estimated concentrations of 18 congeners ranging from PCB 52 to PCB 206. Total 

PAH was computed as the sum of the detected and estimated 

concentrations of 13 PAHs: napthalene, 2-methylnaphthalene, 

acenaphthylene, acenaphthene, 9H-fluorene, phenanthrene, 

anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, 

dibenzo(a,h)anthracene, and benzo(a)pyrene (Ingersoll and 

others, 2000). 

The most notable result is the very high PAH concentration in the sample from sealed parking lots in the Lake Como 

watershed. Total PAH concentration in the sealed parking lot 

sample is 980,000 micrograms per kilogram, more than 30 

times greater than the total PAH concentration of 32,000 micrograms per kilogram measured in the unsealed parking lot sample (table 2). These concentrations are consistent with concentrations in particles collected from runoff from sealed and 

unsealed parking lots as reported by Mahler and others (2005) 

for parking lots in Austin. Also noteworthy are the few high 

concentrations of organochlorine pesticides in commercial and 

residential soil. 

References

Arbogast, B.F., ed., 1996, Analytical methods manual for the 

Mineral Resources Surveys Program: U.S. Geological 

Survey Open-File Report 96–525, 248 p.

Baskaran, M., and Naidu, A.S., 1994, 210Pb-derived chronology and the fluxes of 210Pb and 137Cs isotopes into continental shelf sediments, East Chukchi Sea, Alaskan Arctic: 

Geochimica et Cosmochimica Acta, v. 59, p. 4,435–4,448.

Briggs, P.H., and Meier, A.L., 2003, The determination of 

forty-two elements in geological materials by inductivelycoupled plasma-mass spectrometry, in Taggart, J.E., Jr., ed., 

Analytical methods for chemical analysis of geologic and 

other materials, U.S. Geological Survey: U.S. Geological 

Survey Open-File Report 02–223–I, 14 p.

Brown, Z.A., O'Leary, R.M., Hageman, P.L., and Crock, J.G., 

2003, Mercury in water, geologic, and plant materials by 

continuous flow-cold vapor-atomic absorption spectroscopy, 

in Taggart, J.E., Jr., ed., Analytical methods for chemical 

analysis of geologic and other materials, U.S. Geological 

Survey: U.S. Geological Survey Open-File Report 

02–223–M, 9 p.

Cutshall, N.H., Larsen, I.L., and Olsen, C.R., 1983, Direct 

analysis of 210Pb in sediment samples—Self-absorption 

corrections: Nuclear Instruments and Methods, v. 306, 

p. 309–312.

Durand, B., and Nicaise, G., 1980, Procedures for kerogen isolation, in Durand, B., ed., Kerogen—Insoluble organic matter 

from sedimentary rocks: Paris, Editions Technip, p. 35–53. 

Fuller, C.C., van Geen, A., Baskaran, M., and Anima, R., 1999, 

Sediment chronology in San Francisco Bay, California, 

defined by 210Pb, 234Th, 137Cs, and 239,240Pu: Marine 

Chemistry, v. 64, p. 7–27.

Gelinas, Yves, Prentice, K.M., Baldock, J.A., and Hedges, J.I., 

2001, An improved thermal oxidation method for the quantification of soot/graphitic black carbon in sediments and soils: 
References 7

Environmental Science & Technology, v. 35, no. 17, 

p. 3,519–3,525. 

Guy, H.P., 1969, Laboratory theory and methods for sediment 

analysis: U.S. Geological Survey Techniques of WaterResources Investigations, book 5, chap. C1, 58 p.

Ingersoll, C.G., MacDonald, D.D., Wang, N., Crane, J.L., 

Field, L.J., Haverland, P.S., Kemble, N.E., Lindskoog, R.A., 

Severn, C., and Smorong, D.E., 2000, Prediction of sediment 

toxicity using consensus-based freshwater sediment quality 

guidelines: U.S. Environmental Protection Agency, Great 

Lakes National Program Office, EPA 905/R–00/007, 

33 p.

Li, Jun, and Werth, C.J., 2001, Evaluating competitive sorption 

mechanisms of volatile organic compounds in soils and sediments using polymers and zeolites: Environmental Science 

& Technology, v. 35, no. 3, p. 568–574.

MacDonald, D.D., Ingersoll, C.G., and Berger, T.A., 2000, 

Development and evaluation of consensus-based sediment 

quality guidelines for freshwater ecosystems: Archives of 

Environmental Contamination and Toxicology, v. 39, 

p. 20–31.

Mahler, B.J., and Van Metre, P.C., 2003, A simplified approach 

for monitoring hydrophobic organic contaminants associated 

with suspended sediments—Methodology and applications: 

Archives of Environmental Contamination and Toxicology, 

v. 44, no. 3, p. 288–297.

Mahler, B.J., Van Metre, P.C., Bashara, T.J., Wilson, J.T., and 

Johns, D.A., 2005, Parking lot sealcoat—An unrecognized 

source of urban polycyclic aromatic hydrocarbons: Environmental Science & Technology, v. 39, no. 15, p. 5,560–5,566.

Noriega, M.C., Wydoski, D.S., and Foreman, W.T., 2003, 

Methods of analysis by the U.S. Geological Survey National 

Water Quality Laboratory—Determination of organochlorine pesticides and polychlorinated biphenyls in bottom and 

suspended sediment by gas chromatography with electroncapture detection: U.S. Geological Survey Water-Resources 

Investigations Report 03–4293, 46 p.

Olson, M.C., Iverson, J.L., Furlong, E.T., and Schroeder, M.P., 

2003, Methods of analysis by the U.S. Geological Survey 

National Water Quality Laboratory—Determination of polycyclic aromatic hydrocarbon compounds in sediment by gas 

chromatography/mass spectrometry: U.S. Geological Survey 

Water-Resources Investigations Report 03–4318, 45 p.

Robbins, J.A., and Edgington, D.N., 1975, Determination of 

recent sedimentation rates in Lake Michigan using 210Pb 

and 137Cs: Geochimica et Cosmochimica Acta, v. 39, 

p. 285–304.

Swift, R.S., 1996, Part 3–Chemical methods, in Sparks, D.L., 

ed., Methods of soil analysis: Madison, Wis., Soil Science 

Society of America, Book Series No. 5. 

U.S. Environmental Protection Agency, 1997, The incidence 

and severity of sediment contamination in surface waters of 

the United States, v. 1 of National sediment quality survey: 

U.S. Environmental Protection Agency, Office of Science 

and Technology, EPA 823–R–97–006.

U.S. Environmental Protection Agency, 2005, 2004 National 

listing of fish and wildlife advisories: Washington, D.C., 

U.S. Environmental Protection Agency, Office of Water, 

Fact Sheet EPA 823–F–02–010, 6 p. 

U.S. Environmental Protection Agency, 2006, Total maximum 

daily loads—National section 303(d) list fact sheet: accessed 

June 30, 2006, at http:\\oaspub.epa.gov/waters/

national_rept.control

Van Metre, P.C., and Mahler, B.J., 2004, Contaminant trends in 

reservoir sediment cores as records of influent stream quality: Environmental Science & Technology, v. 38, no. 11, 

p. 2,978–2,986.

Van Metre, P.C., Wilson, J.T., Fuller, C.C., Callender, Edward, 

and Mahler, B.J., 2004, Collection, analysis, and age-dating 

of sediment cores from 56 U.S. lakes and reservoirs sampled 

by the U.S. Geological Survey, 1992–2001: U.S. Geological 

Survey Scientific Investigations Report 2004–5184, 180 p.

Van Metre, P.C., Wilson, J.T., Harwell, G.R., Gary, M.O., 

Heitmuller, F.T., and Mahler, B.J., 2003, Occurrence, trends, 

and sources in particle-associated contaminants in selected 

streams and lakes in Fort Worth, Texas: U.S. Geological 

Survey Water-Resources Investigations Report 03–4169, 

66 p.
Table 1 Table 1. Selected chlorinated hydrocarbon compound concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and 

samples collected in Lake Como and Fosdic Lake watersheds, October 2004. [In micrograms per kilogram except as indicated; parking lot dust samples not available from Fosdic Lake; concentration in bold exceeds probable effect concentration (MacDon

ID, identifier; resid., residential; <, nondetection at indicated value; comm., commercial; pkng., parking; lab. dup., laboratory duplicate; E, estimated; --, not applicable; na, not a

Sample ID (core interval, in centimeters) Sample type Laboratory set number Sample mass (grams) Aldrin p,p’-DDD p,p’-DDE p,p’-DDT Dieldr

Lake Como CMO resid. asphalt street dust Street dust (sweeping) 200512301 25.0 <2.0 <24 1.8 <42 <5.0 

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512301 27.4 <2.0 <25 <1.5 <20 <5.0 CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512301 24.9 <2.0 <2.5 <1.5 <1.0 <.5 CMO comm. soil Soil (grab) 200512301 23.2 <2.0 <2.5 1.4 1.4 1.6 CMO comm. soil lab. dup. Soil (grab) 200512301 23.2 <2.0 <2.5 1.3 1.7 2.0 CMO resid. soil #1 Soil (grab) 200512301 24.5 <2.0 <2.5 7.4 <1.0 17 CMO resid. soil #2 Soil (grab) 200512301 23.8 <2.0 31 110 35 71 CMO (0–5) Lake-bottom sediment (core) 200509402 8.9 E3.3 17 8.4 <2.0 14 CMO (10–15) Lake-bottom sediment (core) 200509402 10.2 <4.0 16 E9.4 <2.0 7.5 CMO (25–30) Lake-bottom sediment (core) 200509402 11.1 <4.0 16 E12 <2.0 6.8 Como inflow Suspended sediment 200509402 .50 <94 <118 <71 <47 61 Como inflow Streambed sediment (grab) 200506805 21.1 <2.0 E1.9 3.5 E1.0 6.9 

Fosdic Lake FOS resid. asphalt street dust Street dust (sweeping) 200512301 24.9 <2.0 <2.5 4.6 <2.4 2.9 

FOS comm. soil Soil (grab) 200515209 29.4 <2.0 E2.0 180 63 23 FOS resid. soil #1 Soil (grab) 200512301 24.5 <2.0 E5.5 17 4.5 23 FOS resid. soil #2 Soil (grab) 200515209 29.1 <2.0 6.1 19 12 51 FOS (0–5) Lake-bottom sediment (core) 200509402 8.4 4.6 27 28 3.0 24 FOS (5–10) Lake-bottom sediment (core) 200509402 7.6 <6.0 31 32 15 21 

FOS (10–15) Lake-bottom sediment (core) 200509402 7.4 <6.0 23 28 4.9 12 FOS (15–20) Lake-bottom sediment (core) 200509402 8.3 <2.0 37 27 E1.8 7.2 FOS (20–25) Lake-bottom sediment (core) 200515209 11.5 <4.0 16 22 E1.3 3.0 FOS (25–30) Lake-bottom sediment (core) 200515209 12.1 <4.0 22 37 E1.2 3.5 

Fosdic inflow Suspended sediment 200509402 1.2 <40 <50 <30 31 17 Fosdic inflow Streambed sediment (grab) 200509402 23.7 <2.0 12 E5.4 18 17 Sediment-quality guidelinesThreshold effect concentration -- -- -- na 4.88 3.16 4.16 1.9 Probable effect concentration -- -- -- na 28 31.3 62.9 61.8 
Table 1. Selected chlorinated hydrocarbon compound concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and 

samples collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. 

Sample ID

(core interval, in centimeters)

Sample

type

Laboratory

set number

cisChlordane trans- Chlor- dane trans- Non- achlor PCB Aroclor 1016/1242 PCB Aroclor 1254 PCB Aroclor 1260 P

Lake Como

CMO resid. asphalt street dust Street dust (sweeping) 200512301 <1.0 <1.0 <1.0 <5.0 6.3 6.8 <CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512301 <10 <5.0 <10 <5.0 7.8 E3.8 <CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512301 E.7 <.5 <1.0 <5.0 23 E2.5 ECMO comm. soil Soil (grab) 200512301 1.0 1.7 1.3 <5.0 <5.0 7.9 <CMO comm. soil lab. dup. Soil (grab) 200512301 1.3 2.2 2.1 <5.0 <5.0 7.2 <CMO resid. soil #1 Soil (grab) 200512301 13 10 27 <5.0 24 41 <CMO resid. soil #2 Soil (grab) 200512301 21 26 53 <5.0 E3.8 25 <CMO (0–5) Lake-bottom sediment (core) 200509402 13 14 13 10 13 17 <2CMO (10–15) Lake-bottom sediment (core) 200509402 9.0 11 8.5 E6.3 E13 E20 <2CMO (25–30) Lake-bottom sediment (core) 200509402 12 14 10 E9.3 E21 E29 <2Como inflow Suspended sediment 200509402 E27 34 E32 <235 <235 <235 <4Como inflow Streambed sediment (grab) 200506805 3.4 3.5 3.3 <5.0 9.1 9.9 <

Fosdic Lake

FOS resid. asphalt street dust Street dust (sweeping) 200512301 2.8 2.7 2.2 <5.0 13 E3.6 EFOS comm. soil Soil (grab) 200515209 3.1 4.6 2.5 <5.0 10 8.3 <FOS resid. soil #1 Soil (grab) 200512301 2.3 2.0 6.8 <5.0 6.3 16 <FOS resid. soil #2 Soil (grab) 200515209 <1.0 <.5 <1.0 E2.3 E3.4 E6.2 <FOS (0–5) Lake-bottom sediment (core) 200509402 25 33 25 <10 31 40 <2FOS (5–10) Lake-bottom sediment (core) 200509402 24 29 23 <15 34 42 <FOS (10–15) Lake-bottom sediment (core) 200509402 15 18 13 <15 31 47 <3FOS (15–20) Lake-bottom sediment (core) 200509402 8.3 12 6.9 <5.0 35 48 <FOS (20–25) Lake-bottom sediment (core) 200515209 6.3 9.7 5.1 33 29 49 EFOS (25–30) Lake-bottom sediment (core) 200515209 6.3 12 4.9 <10 37 65 EFosdic inflow Suspended sediment 200509402 E8.3 E9.2 E8.2 <100 <100 <100 <2Fosdic inflow Streambed sediment (grab) 200509402 3.7 4.1 4.1 <5.0 E2.4 E3.0 <Sediment-quality guidelinesThreshold effect concentration -- -- na na na na na na Probable effect concentration -- -- na na na na na na 
Table 1. Selected chlorinated hydrocarbon compound concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and 

samples collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. Sample ID (core interval, in centimeters) Sample type Laboratory set number PCB 110 PCB 118 PCB 138 PCB 146 PCB 149 PCB 151 PCB 170 P

1

Lake Como CMO resid. asphalt street dust Street dust (sweeping) 200512301 <1.0 <1.0 E0.6 <1.0 <1.0 <1.0 <1.0 <

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512301 E.7 E.5 <1.0 <1.0 <1.0 <1.0 <1.0 ECMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512301 2.2 1.8 1.6 <1.0 1.0 <1.0 <1.0 <CMO comm. soil Soil (grab) 200512301 <1.0 <1.0 E.8 <1.0 <1.0 <1.0 <1.0 <CMO comm. soil lab. dup. Soil (grab) 200512301 <1.0 <1.0 E.7 <1.0 <1.0 <1.0 <1.0 <CMO resid. soil #1 Soil (grab) 200512301 2.7 3.0 9.0 E.9 2.6 E.5 2.3 CMO resid. soil #2 Soil (grab) 200512301 <1.0 <1.0 2.2 <1.0 E.6 <1.0 E.9 ECMO (0–5) Lake-bottom sediment (core) 200509402 E1.3 <2.0 2.0 <2.0 E1.1 <2.0 <2.0 <2CMO (10–15) Lake-bottom sediment (core) 200509402 E1.4 <2.0 2.1 <2.0 E1.3 <2.0 <2.0 <2CMO (25–30) Lake-bottom sediment (core) 200509402 2.3 E1.5 3.3 <2.0 2.0 <2.0 E1.1 EComo inflow Suspended sediment 200509402 <47 <47 <47 <47 <47 <47 <47 <4Como inflow Streambed sediment (grab) 200506805 E.7 E.5 1.5 <1.0 E.5 <1.0 E.5 <

Fosdic Lake FOS resid. asphalt street dust Street dust (sweeping) 200512301 1.2 1.1 1.4 <1.0 E.6 <1.0 <1.0 <

FOS comm. soil Soil (grab) 200515209 1.7 1.2 2.2 <1.0 E.9 <1.0 E.6 <FOS resid. soil #1 Soil (grab) 200512301 E.6 E.9 2.3 <1.0 E.8 <1.0 E.8 <FOS resid. soil #2 Soil (grab) 200515209 <1.0 <1.0 1.5 <1.0 <1.0 <1.0 <1.0 <FOS (0–5) Lake-bottom sediment (core) 200509402 2.8 2.4 5.1 <2.0 2.8 <2.0 E1.6 EFOS (5–10) Lake-bottom sediment (core) 200509402 3.2 E2.5 5.7 <3.0 3.3 <3.0 E1.8 EFOS (10–15) Lake-bottom sediment (core) 200509402 3.1 E2.4 5.8 <3.0 3.4 <3.0 E1.9 EFOS (15–20) Lake-bottom sediment (core) 200509402 3.5 E2.6 6.5 <1.0 3.8 <1.0 E2.1 EFOS (20–25) Lake-bottom sediment (core) 200515209 4.8 4.0 7.7 E1.8 5.4 E1.3 4.0 2FOS (25–30) Lake-bottom sediment (core) 200515209 5.9 4.9 9.2 2.4 6.8 2.5 5.0 3Fosdic inflow Suspended sediment 200509402 <20 <20 <20 <20 <20 <20 <20 <2Fosdic inflow Streambed sediment (grab) 200509402 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <Sediment-quality guidelinesThreshold effect concentration -- -- na na na na na na na nProbable effect concentration -- -- na na na na na na na n
Table 1. Selected chlorinated hydrocarbon compound concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and 

samples collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. 

Sample ID

(core interval, in centimeters)

Sample

type

Laboratory

set number

PCB

187 

PCB

194 

PCB

206 

Calculate

Total

DDT

Technical

chlordane

Lake Como

CMO resid. asphalt street dust Street dust (sweeping) 200512301 <1.0 <1.0 <1.0 E1.8 <3.0 CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512301 <1.0 <1.0 <1.0 <47 <25 CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512301 <1.0 <1.0 <1.0 <5.0 E1.1 CMO comm. soil Soil (grab) 200512301 <1.0 <1.0 E.6 E2.8 E6.4 CMO comm. soil lab. dup. Soil (grab) 200512301 <1.0 <1.0 <1.0 E3.0 E9.0 CMO resid. soil #1 Soil (grab) 200512301 1.2 <1.0 E.5 E7.4 E80 CMO resid. soil #2 Soil (grab) 200512301 1.5 <1.0 <1.0 176 E160 

CMO (0–5) Lake-bottom sediment (core) 200509402 <2.0 <2.0 <2.0 E26 E64 

CMO (10–15) Lake-bottom sediment (core) 200509402 E1.0 <2.0 <2.0 E25 E45 CMO (25–30) Lake-bottom sediment (core) 200509402 E1.6 <2.0 <2.0 E28 E57 Como inflow Suspended sediment 200509402 <47 <47 <47 <236 E149 Como inflow Streambed sediment (grab) 200506805 E.6 <1.0 <1.0 E6.4 E16 

Fosdic Lake

FOS resid. asphalt street dust Street dust (sweeping) 200512301 <1.0 <1.0 <1.0 E4.6 E12 FOS comm. soil Soil (grab) 200515209 E.6 <1.0 <1.0 245 E16 FOS resid. soil #1 Soil (grab) 200512301 E.8 <1.0 E.8 E27 E18 FOS resid. soil #2 Soil (grab) 200515209 E.6 <1.0 <1.0 37 <2.5 FOS (0–5) Lake-bottom sediment (core) 200509402 2.2 E1.1 <2.0 58 E132 

FOS (5–10) Lake-bottom sediment (core) 200509402 E2.3 <3.0 <3.0 79 E121 

FOS (10–15) Lake-bottom sediment (core) 200509402 E2.5 <3.0 <3.0 51 E73 FOS (15–20) Lake-bottom sediment (core) 200509402 E2.7 <1.0 <1.0 E65 E44 FOS (20–25) Lake-bottom sediment (core) 200515209 3.1 2.4 E1.9 E39 E34 

FOS (25–30) Lake-bottom sediment (core) 200515209 4.2 3.1 2.7 E60 E37 

Fosdic inflow Suspended sediment 200509402 <20 <20 <20 E31 E41 

Fosdic inflow Streambed sediment (grab) 200509402 <1.0 <1.0 <1.0 E35 E19 

Sediment-quality guidelinesThreshold effect concentration -- -- na na na 5.28 3.24 Probable effect concentration -- -- na na na 572 17.6 
Table 2 Table 2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and strea

collected in Lake Como and Fosdic Lake watersheds, October 2004. [In micrograms per kilogram except for ratios; parking lot dust samples not available from Fosdic Lake; concentration in bold exceeds probable effect concentration (MacDonal

ID, identifier; resid., residential; <, nondetection at indicated value; E, estimated; comm., commercial; pkng., parking; --, not applicable; na, not available] Sample ID (core interval, in centimeters) Sample type Laboratory set number Mass of sample (grams) Naph- thalene C1-128 Isomers, methylated naphtha- lenes 2- Ethyl- naph- thalene 2,6- Dimethyl- naphtha- lene 1,6- Dimethyl- naphtha- lene 

Is

a

t

Lake Como CMO resid. asphalt street dust Street dust (sweeping) 200512303 25.0 <10 E26 <10 <10 <10 

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512303 27.4 490 E617 E167 E156 240 CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512303 24.9 38 E87 <10 18 21 CMO comm. soil Soil (grab) 200512303 23.2 18 E39 <11 12 <11 CMO resid. soil #1 Soil (grab) 200512303 24.5 <10 E15 <10 <10 <10 CMO resid. soil #2 Soil (grab) 200512303 23.8 E9.8 E22 <11 <11 <11 CMO (0–5) Lake-bottom sediment (core) 200509403 8.9 <30 E130 <30 2,180 443 ECMO (10–15) Lake-bottom sediment (core) 200509403 10.1 <25 E189 <25 1,720 385 ECMO (25–30) Lake-bottom sediment (core) 200509403 11.1 30 E307 <20 1,960 168 EComo inflow Suspended sediment 200509403 .5 <470 E70 <470 <470 <470 Como inflow Streambed sediment (grab) 200506806 21.1 20 E45 <12 74 28 

Fosdic Lake FOS resid. asphalt street dust Street dust (sweeping) 200512303 24.9 <10 E155 <10 22 <10 

FOS comm. soil Soil (grab) 200515210 29.4 142 E402 32 80 78 FOS resid. soil #1 Soil (grab) 200512303 24.5 <10 E14 <10 <10 <10 FOS resid. soil #2 Soil (grab) 200515210 29.1 E7.9 E34 <9 E8.1 E8.4 FOS (0–5) Lake-bottom sediment (core) 200509403 8.4 <30 E160 <30 1,570 425 EFOS (5–10) Lake-bottom sediment (core) 200509403 7.6 <35 E153 <35 1,380 248 EFOS (10–15) Lake-bottom sediment (core) 200509403 7.4 <35 E160 <35 1,550 294 EFOS (15–20) Lake-bottom sediment (core) 200509403 8.3 <30 E187 <30 1,470 266 EFOS (20–25) Lake-bottom sediment (core) 200515210 11.5 <22 E305 <22 1,050 184 EFOS (25–30) Lake-bottom sediment (core) 200515210 12.1 <21 E312 <21 991 175 EFosdic inflow Suspended sediment 200509403 1.2 <200 E63 <200 <200 <200 Fosdic inflow Streambed sediment (grab) 200509403 23.7 E10 E14 <11 20 16 Sediment-quality guidelinesThreshold effect concentration -- -- -- 176 na na na na Probable effect concentration -- -- -- 561 na na na na 
Table 2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and strea

collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. 

Sample ID

(core interval, in centimeters) Sample type

Laboratory

set

number

Acenaphthene 

C3-128

Isomers,

C3-

alkylatednaphthalenes

2,3,6-

Trimethylnaphthalene 9H- Fluor- ene

C4-128

Isomers,

C4-

alkylated

naphthalenes

1-Meth

9Hfluoren

Lake Como

CMO resid. asphalt street dust Street dust (sweeping) 200512303 E7.9 <45 <10 11 <30 <10 CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512303 2,670 E1,250 <180 4,740 E884 404 

CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512303 118 <140 <10 198 <75 23 

CMO comm. soil Soil (grab) 200512303 70 E88 <11 66 <35 <11 CMO resid. soil #1 Soil (grab) 200512303 <10 E47 <10 <10 <20 <10 CMO resid. soil #2 Soil (grab) 200512303 34 <50 <11 41 <20 <11 CMO (0–5) Lake-bottom sediment (core) 200509403 E13 <330 <30 49 <260 <30 CMO (10–15) Lake-bottom sediment (core) 200509403 31 <370 <25 71 <260 <25 CMO (25–30) Lake-bottom sediment (core) 200509403 39 <350 <20 79 <260 <20 Como inflow Suspended sediment 200509403 <470 <470 <470 E219 <650 <470 

Como inflow Streambed sediment (grab) 200506806 76 E73 <12 80 <45 26 

Fosdic Lake

FOS resid. asphalt street dust Street dust (sweeping) 200512303 36 <95 <10 44 <45 <10 FOS comm. soil Soil (grab) 200515210 1,260 E954 66 1,590 E467 170 

FOS resid. soil #1 Soil (grab) 200512303 13 <40 <10 15 <15 <10 FOS resid. soil #2 Soil (grab) 200515210 52 E53 <9 64 <19 12 FOS (0–5) Lake-bottom sediment (core) 200509403 38 <360 <30 89 <200 <30 FOS (5–10) Lake-bottom sediment (core) 200509403 37 <340 <35 86 <160 <35 FOS (10–15) Lake-bottom sediment (core) 200509403 38 <390 <35 82 <180 <35 FOS (15–20) Lake-bottom sediment (core) 200509403 52 <400 <30 90 <150 <30 FOS (20–25) Lake-bottom sediment (core) 200515210 65 E305 <22 88 <130 26 FOS (25–30) Lake-bottom sediment (core) 200515210 60 E343 <21 98 <120 33 Fosdic inflow Suspended sediment 200509403 <200 <520 <200 E146 <650 E103 

Fosdic inflow Streambed sediment (grab) 200509403 29 E61 E6.7 40 E47 E8.5 Sediment-quality guidelinesThreshold effect concentration -- -- na na na 77.4 na na Probable effect concentration -- -- na na na 536 na na 
Table 2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and strea

collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. Sample ID (core interval, in centimeters) Sample type Laboratory set number C5-128 Isomers, C5-alkylated naphtha- lenes 2- Methyl- anthra- cene 4,5- Methylene- phenan- threne C1-178 Isomers, methylated phenanthrene/ anthracenes 1- Methyl- phenan- threne 

Lake Como CMO resid. asphalt street dust Street dust (sweeping) 200512303 <10 <10 10 E37 <10 

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512303 <180 1,560 13,600 E27,800 5,280 CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512303 <10 54 561 E1,050 184 

CMO comm. soil Soil (grab) 200512303 <10 34 149 E425 78 CMO resid. soil #1 Soil (grab) 200512303 <10 <10 <10 E32 <10 CMO resid. soil #2 Soil (grab) 200512303 <11 16 89 E195 36 CMO (0–5) Lake-bottom sediment (core) 200509403 <55 <30 77 E264 <30 CMO (10–15) Lake-bottom sediment (core) 200509403 <45 <25 96 E267 <25 CMO (25–30) Lake-bottom sediment (core) 200509403 <35 <20 <20 E416 <20 Como inflow Suspended sediment 200509403 <470 E230 E296 E1,510 E276 Como inflow Streambed sediment (grab) 200506806 <30 29 172 E419 86 

Fosdic Lake FOS resid. asphalt street dust Street dust (sweeping) 200512303 <15 <10 52 E143 24 

FOS comm. soil Soil (grab) 200515210 <100 668 1,880 E4,940 1,800 

FOS resid. soil #1 Soil (grab) 200512303 <10 17 17 E70 E8.4 FOS resid. soil #2 Soil (grab) 200515210 <9 25 110 E284 49 FOS (0–5) Lake-bottom sediment (core) 200509403 <40 <30 123 E271 <30 FOS (5–10) Lake-bottom sediment (core) 200509403 <40 <30 123 E294 <30 FOS (10–15) Lake-bottom sediment (core) 200509403 <40 <35 122 E285 <35 FOS (15–20) Lake-bottom sediment (core) 200509403 <40 <30 151 E341 <30 FOS (20–25) Lake-bottom sediment (core) 200515210 <70 44 162 E403 61 FOS (25–30) Lake-bottom sediment (core) 200515210 <45 48 190 E411 65 Fosdic inflow Suspended sediment 200509403 <210 E154 250 E1,830 258 Fosdic inflow Streambed sediment (grab) 200509403 <11 20 99 E253 47 Sediment-quality guidelinesThreshold effect concentration -- -- na na na na na Probable effect concentration -- -- na na na na na 
Table 2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and strea

collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. 

Sample ID

(core interval, in centimeters) Sample type

Laboratory

set

number

Pyrene 

C3-178

Isomers,

C3-alkylated

phenanthrene/

anthracenes

C4-178

Isomers,

C4-alkylated

phenanthrene/

anthracenes

1-

Methylpyrene

I

m

fluo

Lake Como

CMO resid. asphalt street dust Street dust (sweeping) 200512303 131 <15 <10 <10 CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512303 215,000 E2,410 E1,720 5,870 ECMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512303 6,610 <30 <30 199 CMO comm. soil Soil (grab) 200512303 2,250 <25 <15 78 CMO resid. soil #1 Soil (grab) 200512303 104 <15 <15 <10 CMO resid. soil #2 Soil (grab) 200512303 1,470 E19 <11 48 CMO (0–5) Lake-bottom sediment (core) 200509403 1,160 <245 <80 <95 CMO (10–15) Lake-bottom sediment (core) 200509403 1,470 <220 <100 <100 CMO (25–30) Lake-bottom sediment (core) 200509403 2,000 <240 <80 <110 Como inflow Suspended sediment 200509403 9,240 E1,140 <520 <470 Como inflow Streambed sediment (grab) 200506806 2,060 <170 <40 76 

Fosdic Lake

FOS resid. asphalt street dust Street dust (sweeping) 200512303 791 <20 <10 23 FOS comm. soil Soil (grab) 200515210 34,500 <1,260 <500 1,040 E

FOS resid. soil #1 Soil (grab) 200512303 346 <10 <10 12 FOS resid. soil #2 Soil (grab) 200515210 1,210 <40 <15 45 FOS (0–5) Lake-bottom sediment (core) 200509403 1,380 <150 <60 <100 FOS (5–10) Lake-bottom sediment (core) 200509403 1,550 <170 <80 <120 FOS (10–15) Lake-bottom sediment (core) 200509403 1,550 <190 <90 <120 FOS (15–20) Lake-bottom sediment (core) 200509403 2,030 <190 <70 <120 FOS (20–25) Lake-bottom sediment (core) 200515210 2,060 <120 <55 76 FOS (25–30) Lake-bottom sediment (core) 200515210 1,940 <150 <70 77 Fosdic inflow Suspended sediment 200509403 5,740 E1,150 <360 253 Fosdic inflow Streambed sediment (grab) 200509403 1,470 E133 <40 51 Sediment-quality guidelinesThreshold effect concentration -- -- 195 na na na Probable effect concentration -- -- 1,520 na na na 
Table 2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and strea

collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. Sample ID (core interval, in centimeters) Sample type Laboratory set number C5-178 Isomers, C5-alkylated phenanthrene/ anthracenes Benz(a)- anthra- cene Chry- sene C3-202 Isomers, C3-alkylated fluoranthene/ pyrenes C1-22

me

be

ant

ch

Lake Como CMO resid. asphalt street dust Street dust (sweeping) 200512303 <20 56 97 <30 

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512303 <19,000 94,900 131,000 <14,500 <3CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512303 <610 2,620 4,150 <370 <

CMO comm. soil Soil (grab) 200512303 <260 1,100 1,650 <190 

CMO resid. soil #1 Soil (grab) 200512303 <30 49 76 <30 CMO resid. soil #2 Soil (grab) 200512303 <210 738 1,190 <110 CMO (0–5) Lake-bottom sediment (core) 200509403 <200 439 1,160 <137 CMO (10–15) Lake-bottom sediment (core) 200509403 <210 586 1,240 <190 CMO (25–30) Lake-bottom sediment (core) 200509403 <240 808 1,740 <240 

Como inflow Suspended sediment 200509403 <1,390 2,760 7,690 <940 <

Como inflow Streambed sediment (grab) 200506806 <330 1,100 1,580 <110 

Fosdic Lake FOS resid. asphalt street dust Street dust (sweeping) 200512303 <70 316 483 <55 

FOS comm. soil Soil (grab) 200515210 <260 16,200 25,600 <4,930 <

FOS resid. soil #1 Soil (grab) 200512303 <45 150 275 <45 FOS resid. soil #2 Soil (grab) 200515210 <15 643 888 <110 FOS (0–5) Lake-bottom sediment (core) 200509403 <200 606 1,040 <170 FOS (5–10) Lake-bottom sediment (core) 200509403 <230 672 1,200 <190 FOS (10–15) Lake-bottom sediment (core) 200509403 <260 662 1,230 <210 FOS (15–20) Lake-bottom sediment (core) 200509403 <290 866 1,540 <220 

FOS (20–25) Lake-bottom sediment (core) 200515210 <45 899 1,710 <230 

FOS (25–30) Lake-bottom sediment (core) 200515210 <40 965 1,800 <210 

Fosdic inflow Suspended sediment 200509403 <810 2,090 4,600 <680 <

Fosdic inflow Streambed sediment (grab) 200509403 <170 727 1,050 <130 Sediment-quality guidelinesThreshold effect concentration -- -- na 108 166 na Probable effect concentration -- -- na 1,050 1,290 na 
Table 2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and strea

collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. 

Sample ID

(core interval, in centimeters) Sample type

Laboratory

set

number

C5-202

Isomers,

C5-alkylated

fluoranthene/

pyrenes

C2-228 Isomers,

C2-alkylated

benzo(a)-

anthracene/

chrysenes

Benzo(b)-

fluoranthene

Benzo(k)-

fluoranthene Benzo

pyre

Lake Como

CMO resid. asphalt street dust Street dust (sweeping) 200512303 <15 <40 E103 E72 7CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512303 <1,540 <8,130 E131,000 E90,000 80,40

CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512303 <55 <200 E4,320 E2,760 2,58CMO comm. soil Soil (grab) 200512303 <25 <140 E1,930 E1,180 1,09CMO resid. soil #1 Soil (grab) 200512303 <15 <55 E91 E65 7CMO resid. soil #2 Soil (grab) 200512303 <20 <95 E1,640 E829 93CMO (0–5) Lake-bottom sediment (core) 200509403 <66 <161 E1,240 E909 74CMO (10–15) Lake-bottom sediment (core) 200509403 <70 <210 E1,290 E1,080 88CMO (25–30) Lake-bottom sediment (core) 200509403 <50 <270 E1,820 E1,440 1,20Como inflow Suspended sediment 200509403 <580 <900 8,630 5,610 4,96Como inflow Streambed sediment (grab) 200506806 <65 <140 1,440 987 91

Fosdic Lake

FOS resid. asphalt street dust Street dust (sweeping) 200512303 <10 <40 E487 E432 31FOS comm. soil Soil (grab) 200515210 <550 <1,810 28,100 21,500 18,60

FOS resid. soil #1 Soil (grab) 200512303 <10 <30 E444 E245 22FOS resid. soil #2 Soil (grab) 200515210 <18 <30 737 650 61FOS (0–5) Lake-bottom sediment (core) 200509403 <200 <170 E1,230 E937 76FOS (5–10) Lake-bottom sediment (core) 200509403 <55 <180 E1,440 E1,160 90FOS (10–15) Lake-bottom sediment (core) 200509403 <60 <200 E1,360 E1,240 96FOS (15–20) Lake-bottom sediment (core) 200509403 <60 <190 E1,970 E1,460 1,21FOS (20–25) Lake-bottom sediment (core) 200515210 <40 <110 1,720 1,260 1,49FOS (25–30) Lake-bottom sediment (core) 200515210 <50 <90 1,720 1,410 1,52Fosdic inflow Suspended sediment 200509403 <340 <790 4,800 3,400 3,26Fosdic inflow Streambed sediment (grab) 200509403 <35 <120 1,040 764 73Sediment-quality guidelinesThreshold effect concentration -- -- na na na na na Probable effect concentration -- -- na na na na na 
Table 2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and strea

collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. Sample ID (core interval, in centimeters) Sample type Laboratory set number C1-252 Isomers, C1-methylated benzopyrene/ perylenes C3-228 Isomers, C3-benzo(a)- anthracene/ chrysenes C2-252 Isomers, C2-alkylated benzopyrene/ perylenes C4-228 Isomers, C4-benzo(a)- anthracene/ chrysenes Benz

(g,h,

peryle

Lake Como CMO resid. asphalt street dust Street dust (sweeping) 200512303 <70 <30 <75 <30 E4

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512303 E45,500 <7,190 <20,700 <12,300 81,60CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512303 E1,510 <150 <580 <420 2,65CMO comm. soil Soil (grab) 200512303 E658 <90 <350 <190 1,02CMO resid. soil #1 Soil (grab) 200512303 E95 <50 <90 <30 E5CMO resid. soil #2 Soil (grab) 200512303 E545 <70 <270 <180 87CMO (0–5) Lake-bottom sediment (core) 200509403 <460 <109 <280 <123 92CMO (10–15) Lake-bottom sediment (core) 200509403 <570 <130 <410 <170 1,01CMO (25–30) Lake-bottom sediment (core) 200509403 <780 <140 <490 <230 1,30Como inflow Suspended sediment 200509403 <3,350 <710 <2390 <960 5,35Como inflow Streambed sediment (grab) 200506806 <600 <90 <350 <60 1,03

Fosdic Lake FOS resid. asphalt street dust Street dust (sweeping) 200512303 <190 <45 <120 <60 25

FOS comm. soil Soil (grab) 200515210 E7,310 <1,020 <3,200 <510 17,20FOS resid. soil #1 Soil (grab) 200512303 <100 <30 <80 <30 E10FOS resid. soil #2 Soil (grab) 200515210 E266 <30 <150 <15 50FOS (0–5) Lake-bottom sediment (core) 200509403 <500 <100 <300 <140 88FOS (5–10) Lake-bottom sediment (core) 200509403 <600 <100 <360 <160 1,04FOS (10–15) Lake-bottom sediment (core) 200509403 <670 <130 <410 <180 1,12FOS (15–20) Lake-bottom sediment (core) 200509403 <750 <150 <450 <190 1,32FOS (20–25) Lake-bottom sediment (core) 200515210 E651 <65 <230 <60 1,36FOS (25–30) Lake-bottom sediment (core) 200515210 E773 <65 <240 <60 1,42Fosdic inflow Suspended sediment 200509403 <2,060 <640 <1,810 <670 3,47Fosdic inflow Streambed sediment (grab) 200509403 E428 <75 <300 <120 67Sediment-quality guidelinesThreshold effect concentration -- -- na na na na na Probable effect concentration -- -- na na na na na 
Table 2. Polycyclic aromatic hydrocarbon (PAH) concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and strea

collected in Lake Como and Fosdic Lake watersheds, October 2004—Continued. 

Sample ID

(core interval, in centimeters) Sample type

Laboratory

set

number

C3-252

Isomers,

C3-

alkylated

benzopyrene/

perylenes

C4-252

Isomers,

C4-

alkylated

benzopyrene/

perylenes

C5-228

Isomers,

C5-

benzo(a)-

anthracene/

chrysenes

C5-252

Isomers,

C5-

alkylated

benzopyrene/

perylenes

Ca

Total

PAH

Fl

t

p

Lake Como

CMO resid. asphalt street dust Street dust (sweeping) 200512303 <25 <25 <25 <30 650 CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 200512303 <3,490 <2,550 <2,360 <28,000 980,000 

CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 200512303 <60 <65 <100 <640 32,000 

CMO comm. soil Soil (grab) 200512303 <60 <45 <55 <250 11,000 CMO resid. soil #1 Soil (grab) 200512303 <35 <20 <30 <25 490 CMO resid. soil #2 Soil (grab) 200512303 <45 <35 <40 <230 7,600 CMO (0–5) Lake-bottom sediment (core) 200509403 <128 <166 <187 <447 5,700 CMO (10–15) Lake-bottom sediment (core) 200509403 <120 <140 <130 <440 7,100 CMO (25–30) Lake-bottom sediment (core) 200509403 <160 <160 <120 <510 10,000 Como inflow Suspended sediment 200509403 <910 <900 <700 <3,520 43,000 

Como inflow Streambed sediment (grab) 200506806 <90 <85 <90 <425 11,000 

Fosdic Lake

FOS resid. asphalt street dust Street dust (sweeping) 200512303 <25 <30 <20 <60 3,900 FOS comm. soil Soil (grab) 200515210 <420 <530 <280 <160 170,000 

FOS resid. soil #1 Soil (grab) 200512303 <30 <20 <20 <45 1,900 FOS resid. soil #2 Soil (grab) 200515210 <25 <17 <14 <20 6,500 FOS (0–5) Lake-bottom sediment (core) 200509403 <90 <120 <100 <350 7,000 FOS (5–10) Lake-bottom sediment (core) 200509403 <110 <130 <60 <380 7,700 FOS (10–15) Lake-bottom sediment (core) 200509403 <120 <110 <90 <380 7,700 FOS (15–20) Lake-bottom sediment (core) 200509403 <130 <120 <90 <440 9,900 FOS (20–25) Lake-bottom sediment (core) 200515210 <40 <40 <60 <210 11,000 FOS (25–30) Lake-bottom sediment (core) 200515210 <50 <50 <60 <210 11,000 Fosdic inflow Suspended sediment 200509403 <790 <580 <470 <2,150 27,000 

Fosdic inflow Streambed sediment (grab) 200509403 <90 <70 <60 <400 7,400 Sediment-quality guidelinesThreshold effect concentration -- -- na na na na 1,610 Probable effect concentration -- -- na na na na 22,800 
Table 3 Table 3. Major and trace element concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and streambed sedimen

Como and Fosdic Lake watersheds, October 2004. [In micrograms per gram except as indicated; parking lot dust samples not available from Fosdic Lake; concentration in bold exceeds probable effect concentration (MacDonald 

ID, identifier; resid., residential; --, not analyzed or not applicable; comm., commercial; pkng., parking; rep., replicate; na, not available; <, nondetection at indicated value] Sample ID (core interval, in centimeters) Sample type Laboratory set number Total carbon (percent) Inorganic carbon (percent) Organic carbon (percent) Alumi- num Cal- cium Iron 

Lake Como CMO resid. asphalt street dust Street dust (sweeping) 5824 -- -- -- 5,550 158,000 11,00

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 5824 -- -- -- 4,860 169,000 8,60CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 5824 -- -- -- 10,200 125,000 19,00CMO comm. soil Soil (grab) 5824 -- -- -- 18,300 55,900 12,00CMO resid. soil # 1 Soil (grab) 5824 -- -- -- 17,700 116,000 14,00CMO resid. soil # 2 Soil (grab) 5824 -- -- -- 32,100 55,000 19,00CMO (0–5) Lake-bottom sediment (core) 5885 -- -- -- 44,900 204,000 25,00CMO (0–5) rep. Lake-bottom sediment (core) 5885 -- -- -- 43,600 208,000 26,00CMO (0–5) rep. Lake-bottom sediment (core) 5885 -- -- -- 44,800 211,000 26,00CMO (10–15) Lake-bottom sediment (core) 5885 -- -- -- 46,200 175,000 24,00CMO (25–30) Lake-bottom sediment (core) 5885 -- -- -- 40,000 180,000 23,00Como inflow Suspended sediment 5713 -- -- -- 45,600 131,000 26,10Como inflow rep. Suspended sediment 5713 -- -- -- 45,400 131,000 26,10Como inflow rep. Suspended sediment 5713 -- -- -- 43,400 126,000 25,00Como inflow Streambed sediment (grab) 5710 7.50 4.64 2.86 20,100 185,000 16,40

Fosdic Lake FOS resid. asphalt street dust Street dust (sweeping) 5824 -- -- -- 5,870 108,000 16,00

FOS resid. asphalt street dust rep. Street dust (sweeping) 5824 -- -- -- 6,160 108,000 16,00FOS resid. asphalt street dust rep. Street dust (sweeping) 5824 -- -- -- 6,240 111,000 17,00FOS comm. soil Soil (grab) 5824 -- -- -- 18,300 49,400 15,00FOS resid. soil # 1 Soil (grab) 5824 -- -- -- 22,600 39,300 17,00FOS resid. soil # 2 Soil (grab) 5824 -- -- -- 24,000 12,000 14,00FOS (0–5) Lake-bottom sediment (core) 5885 -- -- -- 48,300 91,400 27,00FOS (5–10) Lake-bottom sediment (core) 5885 -- -- -- 47,100 77,800 27,00FOS (10–15) Lake-bottom sediment (core) 5885 -- -- -- 51,500 98,200 29,00FOS ((15–20)) Lake-bottom sediment (core) 5885 -- -- -- 50,200 105,000 28,00FOS (20–25) Lake-bottom sediment (core) 5885 -- -- -- 43,700 90,300 25,00FOS (25–30) Lake-bottom sediment (core) 5885 -- -- -- 46,000 88,500 27,00Fosdic inflow Suspended sediment 5713 -- -- -- 62,400 108,000 35,10Fosdic inflow Streambed sediment (grab) 5710 5.03 3.21 1.82 12,100 116,000 19,00Sediment-quality guidelinesThreshold effect concentration -- -- na na na na na na Probable effect concentration -- -- na na na na na na 
Table 3. Major and trace element concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and streambed sedimen

Como and Fosdic Lake watersheds, October 2004—Continued. 

Sample ID

(core interval, in centimeters) Sample type Laboratory set number Sodium Phos- phorus Titan- ium Arsenic Barium Beryll- ium 

Lake Como

CMO resid. asphalt street dust Street dust (sweeping) 5824 600 370 490 4.1 257 0.28 CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 5824 879 330 420 3.0 165 .21 CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 5824 2,120 390 1,100 3.9 174 .36 CMO comm. soil Soil (grab) 5824 1,120 960 3,000 16 178 .68 CMO resid. soil # 1 Soil (grab) 5824 858 700 2,900 6.9 157 .68 CMO resid. soil # 2 Soil (grab) 5824 1,140 1,000 3,300 11 220 1.3 CMO (0–5) Lake-bottom sediment (core) 5885 815 1,400 2,300 13 303 1.4 CMO (0–5) rep. Lake-bottom sediment (core) 5885 793 1,500 2,200 13 288 1.4 CMO (0–5) rep. Lake-bottom sediment (core) 5885 798 1,500 2,400 13 300 1.4 CMO (10–15) Lake-bottom sediment (core) 5885 927 1,300 2,300 12 298 1.6 CMO (25–30) Lake-bottom sediment (core) 5885 788 1,600 2,200 13 269 1.3 Como inflow Suspended sediment 5713 1,100 2,050 2,440 12.5 313 1.4 Como inflow rep. Suspended sediment 5713 1,090 2,040 2,530 12.6 312 1.5 Como inflow rep. Suspended sediment 5713 1,040 1,970 2,320 12.4 303 1.5 Como inflow Streambed sediment (grab) 5710 1,140 686 1,190 7.6 174 .85 

Fosdic Lake

FOS resid. asphalt street dust Street dust (sweeping) 5824 365 360 480 5.9 115 .51 FOS resid. asphalt street dust rep. Street dust (sweeping) 5824 394 360 440 5.9 104 .51 FOS resid. asphalt street dust rep. Street dust (sweeping) 5824 396 380 480 5.9 116 .47 FOS comm. soil Soil (grab) 5824 1,940 530 3,000 5.5 174 .93 FOS resid. soil # 1 Soil (grab) 5824 725 710 3,000 7.6 147 .92 FOS resid. soil # 2 Soil (grab) 5824 1,070 490 3,200 6.5 180 .94 FOS (0–5) Lake-bottom sediment (core) 5885 1,090 1,300 2,700 11 237 1.6 FOS (5–10) Lake-bottom sediment (core) 5885 1,110 1,300 2,800 11 231 1.6 FOS (10–15) Lake-bottom sediment (core) 5885 1,100 1,400 3,100 12 245 1.7 FOS (15–20) Lake-bottom sediment (core) 5885 1,070 1,500 2,900 12 241 1.7 FOS (20–25) Lake-bottom sediment (core) 5885 1,000 1,300 2,600 12 223 1.5 FOS (25–30) Lake-bottom sediment (core) 5885 1,110 1,300 2,800 12 232 1.6 Fosdic inflow Suspended sediment 5713 1,060 1,870 2,420 14.2 299 2.0 Fosdic inflow Streambed sediment (grab) 5710 1,060 409 752 8.4 153 .68 Sediment-quality guidelinesThreshold effect concentration -- -- na na na 9.79 na na Probable effect concentration -- -- na na na 33 na na 
Table 3. Major and trace element concentrations in street dust, parking lot dust, soil, lake-bottom sediment, and suspended and streambed sedimen

Como and Fosdic Lake watersheds, October 2004—Continued. Sample ID (core interval, in centimeters) Sample type Laboratory set number Cop- per Mer- cury Lith- ium Manga- nese Nickel Lead Scan- dium 

Lake Como CMO resid. asphalt street dust Street dust (sweeping) 5824 10.5 0.03 6.3 276 8.0 73.4 1.2 

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 5824 60.1 <.02 5.7 219 5.5 133 .9 

CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 5824 24.8 6.8 9.3 338 9.0 215 1.8 

CMO comm. soil Soil (grab) 5824 19.9 .02 12.4 308 10.7 76.4 3.1 CMO resid. soil # 1 Soil (grab) 5824 14.1 .06 11.8 422 10.7 74.9 3.3 CMO resid. soil # 2 Soil (grab) 5824 238 .06 18.4 547 16.0 105 5.5 CMO (0–5) Lake-bottom sediment (core) 5885 35.8 .08 26.4 721 23.0 93.6 7.4 CMO (0–5) rep. Lake-bottom sediment (core) 5885 35.6 na 24.4 734 23.0 91.2 7.4 CMO (0–5) rep. Lake-bottom sediment (core) 5885 36.1 na 24.8 740 23.3 93.0 7.6 CMO (10–15) Lake-bottom sediment (core) 5885 38.8 .09 29.2 622 22.8 120 7.6 CMO (25–30) Lake-bottom sediment (core) 5885 43.2 .13 23.3 616 21.1 160 6.8 

Como inflow Suspended sediment 5713 79.5 .13 25.5 559 39.1 95.6 7.6 

Como inflow rep. Suspended sediment 5713 80.9 na 24.9 564 40.5 98.8 7.7 Como inflow rep. Suspended sediment 5713 77.3 na 24.0 536 38.0 93.1 7.4 Como inflow Streambed sediment (grab) 5710 20.3 .04 14.7 410 13.8 137 3.8 

Fosdic Lake FOS resid. asphalt street dust Street dust (sweeping) 5824 7.6 .14 7.3 439 7.2 40.0 1.5 

FOS resid. asphalt street dust rep. Street dust (sweeping) 5824 9.2 na 7.9 430 7.4 26.7 1.4 FOS resid. asphalt street dust rep. Street dust (sweeping) 5824 7.8 na 7.7 454 7.3 40.1 1.4 FOS comm. soil Soil (grab) 5824 23.9 .06 15.0 347 20.8 180 3.1 

FOS resid. soil # 1 Soil (grab) 5824 22.1 .15 18.1 479 12.2 78.8 4.1 FOS resid. soil # 2 Soil (grab) 5824 11.6 .05 20.4 449 11.1 70.7 4.1 FOS (0–5) Lake-bottom sediment (core) 5885 34.9 .20 33.6 630 23.5 118 8.2 FOS (5–10) Lake-bottom sediment (core) 5885 36.6 .21 34.2 581 23.6 118 8.4 FOS (10–15) Lake-bottom sediment (core) 5885 40.6 .24 36.6 652 26.0 121 9.0 FOS (15–20) Lake-bottom sediment (core) 5885 42.9 .27 34.5 641 25.7 129 8.9 

FOS (20–25) Lake-bottom sediment (core) 5885 42.3 .30 29.9 544 23.4 148 7.6 

FOS (25–30) Lake-bottom sediment (core) 5885 44.2 .36 32.1 519 24.9 182 8.2 

Fosdic inflow Suspended sediment 5713 56.7 .47 42.7 765 61.1 90.3 10.0 Fosdic inflow Streambed sediment (grab) 5710 9.6 .02 10.6 427 12.1 80.0 2.5 Sediment-quality guidelinesThreshold effect concentration -- -- 31.6 .18 na na 22.7 35.8 na Probable effect concentration -- -- 149 1.06 na na 48.6 128 na 
Table 4 23

Table 4

Table 4. Organic carbon concentrations in street dust, parking lot dust, soil, and lake-bottom sediment samples collected in Lake Como 

and Fosdic Lake watersheds, October 2004. 

[Parking lot dust samples not available from Fosdic Lake. ID, identifier; resid., residential; comm., commercial; pkng., parking] 

Sample ID

(core interval, in centimeters) Sample type

Organic

carbon

(percent)

Sample ID

(core interval, in centimeters) Sample type

Organic

carbon

(percent)

Lake Como Fosdic Lake

CMO resid. asphalt street dust Street dust (sweeping) 2.87 FOS resid. asphalt street dust Street dust (sweeping) 1.85

CMO comm. sealed pkng. lot dust Parking lot dust (sweeping) 3.53

CMO comm. unsealed pkng. lot dust Parking lot dust (sweeping) 2.78 FOS comm. soil Soil (grab) 4.25

FOS resid. soil #1 Soil (grab) 3.96

CMO comm. soil Soil (grab) 2.92 FOS resid. soil #2 Soil (grab) 3.51

CMO resid. soil #1 Soil (grab) 2.80

CMO resid. soil #2 Soil (grab) 4.58 FOS.1 (0–2) Lake-bottom sediment (core) 6.90

FOS.1 (2–4) Lake-bottom sediment (core) 7.43

CMO.2 (0–2) Lake-bottom sediment (core) 4.20 FOS.1 (4–6) Lake-bottom sediment (core) 7.10

CMO.2 (2–4) Lake-bottom sediment (core) 3.64 FOS.1 (6–8) Lake-bottom sediment (core) 8.49

CMO.2 (4–6) Lake-bottom sediment (core) 4.90

CMO.2 (6–8) Lake-bottom sediment (core) 4.87 FOS.1 (8–10) Lake-bottom sediment (core) 7.31

FOS.1 (10–12) Lake-bottom sediment (core) 6.77

CMO.2 (8–10) Lake-bottom sediment (core) 4.29 FOS.1 (12–14) Lake-bottom sediment (core) 6.52

CMO.2 (10–12) Lake-bottom sediment (core) 4.48 FOS.1 (14–16) Lake-bottom sediment (core) 7.45

CMO.2 (12–14) Lake-bottom sediment (core) 5.65

CMO.2 (14–16) Lake-bottom sediment (core) 4.71 FOS.1 (16–18) Lake-bottom sediment (core) 6.81

FOS.1 (18–20) Lake-bottom sediment (core) 7.32

CMO.2 (16–18) Lake-bottom sediment (core) 4.95 FOS.1 (20–22) Lake-bottom sediment (core) 7.38

CMO.2 (18–20) Lake-bottom sediment (core) 4.48 FOS.1 (22–24) Lake-bottom sediment (core) 8.36

CMO.2 (20–22) Lake-bottom sediment (core) 3.75

CMO.2 (22–24) Lake-bottom sediment (core) 4.69 FOS.1 (24–26) Lake-bottom sediment (core) 7.04

FOS.1 (26–28) Lake-bottom sediment (core) 6.87

CMO.2 (24–26) Lake-bottom sediment (core) 5.36 FOS.1 (28–30) Lake-bottom sediment (core) 6.76

CMO.2 (26–28) Lake-bottom sediment (core) 5.04 FOS.1 (30–32) Lake-bottom sediment (core) 6.06

CMO.2 (28–30) Lake-bottom sediment (core) 4.94

CMO.2 (30–32) Lake-bottom sediment (core) 4.10 FOS.1 (32–34) Lake-bottom sediment (core) 6.02

FOS.1 (34–36) Lake-bottom sediment (core) 5.94

FOS.1 (36–38) Lake-bottom sediment (core) 5.75

FOS.1 (38–40) Lake-bottom sediment (core) 5.04
24 Particle-Associated Contaminants, Lake Como and Fosdic Lake Watersheds, Fort Worth, Texas, 2004

Table 6

Table 5. Grain-size distribution in lake-bottom and streambed sediment samples collected in 

Lake Como and Fosdic Lake watersheds, October 2004. 

[ID, identifier; <, less than] 

Table 6. Radionuclide activities in lake-bottom sediment samples collected in Lake Como and Fosdic Lake watersheds, October 2004.

[ID, identifier; pCi/g, picocuries per gram; 1-sig, one standard deviation; dpm/g, disintegrations per minute per gram] 

Sample ID

(core interval, 

in centimeters)

Sample type

Percentage

silt and clay

(<0.063 millimeter)

Percentage

clay

(<0.004 millimeter)

Lake Como

CMO (0–5) Lake-bottom sediment (core) 98.3 59.4

CMO (10–15) Lake-bottom sediment (core) 97.5 61.0

CMO (25–30) Lake-bottom sediment (core) 96.8 64.3

Como inflow Streambed sediment (grab) 37.4 14.1

Fosdic Lake

FOS (0–5) Lake-bottom sediment (core) 79.7 45.3

FOS (5–10) Lake-bottom sediment (core) 78.1 42.6

FOS (10–15) Lake-bottom sediment (core) 84.0 51.6

FOS (15–20) Lake-bottom sediment (core) 83.0 46.2

FOS (20–25) Lake-bottom sediment (core) 71.9 42.2

FOS (25–30) Lake-bottom sediment (core) 76.9 40.4

Fosdic inflow Streambed sediment (grab) 11.7 5.6

Sample ID

(core interval, 

in centimeters)

Sample type

Cesium137

(pCi/g)

Cesium137

1-sig

(pCi/g)

Lead-210

(dpm/g)

Lead-210

1-sig

(dpm/g)

Radium226

(dpm/g)

Radium226

1-sig

(dpm/g)

Calculated values

Excess

lead-210

(dpm/g)

Excess

lead-210

1-sig

(dpm/g)

Natural

log of

excess

lead-210

Lake Como 

CMO (0–5) Lake-bottom sediment (core) 0.076 0.016 25.05 1.01 2.07 0.17 22.98 1.03 3.13

CMO (10–15) Lake-bottom sediment (core) .303 .029 57.00 2.10 4.10 .29 52.90 2.12 3.97

CMO (25–30) Lake-bottom sediment (core) .215 .021 19.40 .82 1.37 .14 18.03 .83 2.89

Fosdic Lake

FOS (0–5) Lake-bottom sediment (core) .163 .046 15.26 .80 1.41 .10 13.85 .80 2.63

FOS (5–10) Lake-bottom sediment (core) .314 .078 15.66 .82 1.51 .10 14.15 .82 2.65

FOS (10–15) Lake-bottom sediment (core) .222 .057 15.10 .79 1.24 .10 13.86 .80 2.63

FOS (15–20) Lake-bottom sediment (core) .240 .062 14.39 .76 1.38 .10 13.01 .77 2.57

FOS (20–25) Lake-bottom sediment (core) .251 .061 12.42 .61 1.14 .06 11.28 .61 2.42

FOS (25–30) Lake-bottom sediment (core) .336 .082 10.79 .61 1.39 .09 9.40 .62 2.24
Prepared by the USGS Texas Water Science Center:

8027 Exchange Drive

Austin, TX 78754–4733

Information regarding water resources in Texas is available at 

http: //tx.usgs.gov/