Water and Streambed Sediment Quality, and Ecotoxicology 

of a Stream along the Blue Ridge Parkway, Adjacent to a 

Closed Landfill, near Roanoke, Virginia: 1999

Water-Resources Investigations Report 03-4116

U.S. Department of the Interior

U.S. Geological Survey
Water and Streambed Sediment Quality, 

and Ecotoxicology of a Stream along the 

Blue Ridge Parkway, Adjacent to a Closed 

Landfill, near Roanoke, Virginia: 1999

By Donna Belval Ebner1, Donald S. Cherry2, and Rebecca J. Currie2

1

 U.S. Geological Survey

2

 Virginia Polytechnic Institute and State University

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with

National Park Service

Water-Resources Investigations Report 03-4116
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2004

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iii

Contents

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

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Purpose and scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Description of the study area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Background information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Previous investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Study Design and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Site selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Water chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Streambed sediment chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Ecological sampling and toxicity testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Benthic macroinvertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Habitat assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Field measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Toxicity testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Water column acute and chronic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Quality assurance and quality control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Water and Streambed Sediment Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Field measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Inorganic constituents and total organic carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Organic compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Quality control samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Streambed sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Inorganic constituents and total organic carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Organic compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Quality control samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Ecotoxicology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Benthic macroinvertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Habitat assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Field measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Water column toxicity testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Sediment toxicity testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
iv

FIGURES

1-2. Maps showing:

1. Location of study area, the Blue Ridge Parkway, and physiographic provinces 

of Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

2. Sampling sites near Blue Ridge Parkway and a closed landfill, 

Roanoke County, Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

3. Photographs showing pool at base of closed landfill, at origin of sampled tributary 

 (site 2), showing 4-inch polyvinyl chloride (PVC) pipe and overflow pipe (A), and 

 the sampled tributary, looking downstream from site 2, facing west (B) 7

4-5. Graphs showing:

4. Ranges in percent difference in concentrations of inorganic constituents and

organic carbon between April 1999 sampling and September 1999 sampling . . . . . . . . . . . . . . . 22

5. Ranges in percent difference in concentrations of inorganic constituents 

associated with streambed sediment between April 1999 sampling and 

September 1999 sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

TABLES

1. Sites sampled for the study of an unnamed stream and its tributary near the 

Blue Ridge Parkway, Roanoke County, Virginia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2. Schedule of field measurements made at all sites, and benthic macroinvertebrate, 

water, and streambed samples collected for ecotoxicological 

assessment at site 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3. Habitat assessment metrics and possible rating for each metric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4. Field measurements of water quality and discharge of an unnamed stream and its 

tributary near the Blue Ridge Parkway, April and September, 1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5. Inorganic constituents analyzed for but not detected in water samples . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6. Inorganic constituents and total organic carbon detected in water samples, 

and associated Virginia Surface Water Quality Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

7. Organic compounds analyzed for but not detected in water and streambed 

sediment samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

8. Organic compounds detected in water samples, and associated Virginia Surface 

Water Quality Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

9. Organic compounds detected in water or streambed sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

10. Inorganic constituents, total organic carbon, and percent moisture in 

streambed sediment samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

11. Organic compounds detected in streambed sediment samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

12. Statistical analysis of benthic macroinvertebrate metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

13. Ranking and statistical analysis of sites for nine benthic 

macroinvertebrate metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

14. Mean values of benthic macroinvertebrate community metrics at each 

site for samples collected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

15. Statistical analysis of benthic macroinvertebrate metrics for samples collected . . . . . . . . . . . . . . . . . . 37

16. Ranking and statistical analysis of sites for nine benthic macroinvertebrate metrics . . . . . . . . . . . . . . 38

17. Benthic macroinvertebrate community metric averages at each site 

for samples collected in September 1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
v

18. Habitat assessment of sites sampled near the Blue Ridge Parkway, September 1999, 

and for the Sinking Creek reference site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

19. Field measurements made in association with collection of water from the 

polyvinyl chloride pipe at site 2 for toxicity tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

20. Results of 48-hour acute toxicity tests for water samples collected from the 

polyvinyl chloride pipe near site 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

21. Chironomus tentans percent survival and mean weight, from 10-day chronic 

toxicity tests of streambed sediment samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

22. Daphnia magna percent survival and mean neonate production, from 10-day chronic 

toxicity tests of streambed sediment samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Appendixes

1. Results of quality assurance samples for inorganic constituents and organic carbon

in water at Blue Ridge Parkway sampling sites, April and September 1999 . . . . . . . . . . . . . . . . . . . . . . . . 48

2. Quality assurance samples collected for organic constituents in water . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

3. Results of quality assurance samples collected for inorganic constituents, 

total organic carbon, and percent moisture in streambed sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

4. Results of quality assurance samples collected for organic constituents 

in streambed sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

5. Benthic macroinvertebrates collected at Blue Ridge Parkway sites and 

resultant summary statistics, April 1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

6. Benthic macroinvertebrates collected at Blue Ridge Parkway sites and

resultant summary statistics, September 1999 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
vi

Conversion Factors and Datum

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F = (1.8 x °C) + 32

Horizontal coordinate information is referenced to North American Datum of 1927 (NAD 27).

Vertical coordinate information is referenced to National Geodetic Vertical Datum 

of 1929 (NGVD 29).

Abbreviated water-quality units: Chemical concentration is reported in milligrams per liter (mg/L) 

or micrograms per liter (μg/L). Milligrams per liter is a unit expressing the concentration of chemical constituents in solution as weight (milligrams) of solute per unit volume (liter) of water. One 

thousand micrograms per liter is equivalent to one milligram per liter. For concentrations less 

than 7,000 mg/L, the numerical value is the same as for concentrations in parts per million. 

Specific electrical conductance of water is reported in microsiemens per centimeter at 25 

degrees Celsius (μS/cm). 

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2)

acre 0.4047 hectare (ha)

Volume

quart (qt) 0.9464 liter (L) 

gallon (gal) 3.785 liter (L)

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

Mass

ounce, avoirdupois (oz) 28.35 gram (g)
Water and Streambed Sediment Quality, and 

Ecotoxicology of a Stream along the Blue Ridge Parkway, 

Adjacent to a Closed Landfill, near Roanoke, Virginia: 

1999

By Donna Belval Ebner, Donald S. Cherry, and Rebecca J. Currie

Abstract

A study was done of the effects of a closed landfill on the quality of water and streambed sediment 

and the benthic macroinvertebrate community of an 

unnamed stream and its tributary that flow through 

Blue Ridge Parkway lands in west-central Virginia. 

The primary water source for the tributary is a 4-

inch polyvinyl chloride (PVC) pipe that protrudes 

from the slope at the base of the embankment bordering the landfill. An unusual expanse of precipitate was observed in the stream near the PVC pipe. 

Stream discharge was measured and water and 

streambed sediment samples were collected at a 

nearby reference site and at three sites downstream 

of the landfill in April and September 1999. Water 

samples were analyzed for major ions, nitrate, total 

and dissolved metals, total dissolved solids, total 

organic carbon, and volatile and semivolatile 

organic compounds, including organochlorine pesticides and polychlorinated biphenyls (PCBs). 

Streambed sediment samples were analyzed for total 

metals, total organic carbon, percent moisture, and 

volatile and semivolatile organic compounds, 

including organochlorine pesticides and PCBs.

The benthic macroinvertebrate community 

within the stream channel also was sampled at the 

four chemical sampling sites and at one additional 

site in April and September. Each of the five sites 

was assessed for physical habitat quality. Water collected periodically at the PVC pipe discharge 

between November 1998 and November 1999 was 

used to conduct 48-hour acute and 7-day chronic 

toxicity tests using selected laboratory test organisms. Two 10-day chronic toxicity tests of streambed sediments collected near the discharge pipe also 

were conducted.

Analyses showed that organic and inorganic constituents in water from beneath the landfill were discharged into the sampled tributary. In April, 79 

percent of inorganic constituents detected in water 

had their highest concentrations at the site closest to 

the landfill; at the same site, 59 percent of inorganic 

constituents detected in streambed sediments were 

at their lowest concentration. The low dissolvedoxygen concentration and relatively low pH in 

ground water from beneath the landfill probably had 

a direct effect on the solubility of metals and other 

constituents, resulting in the high concentration of 

inorganic constituents in water, low concentration in 

sediment, and the development of the precipitate. 

Most constituents in water in April were progressively lower in concentration from the landfill site 

downstream. The highest concentrations for 59 percent of constituents detected in sediment were at the 

farthest downstream site, suggesting that the inorganic constituents came out of solution as the stream 

water was exposed to the atmosphere. In September, 

52 percent of inorganic constituents detected in 

water were at their highest concentrations at the site 

nearest the landfill. Of inorganic constituents 

detected in streambed sediments in September, 60 

percent were at their highest concentrations near the 

landfill. A storm that occurred a few days prior to 

the September sampling probably affected the preceding steady-state conditions and the distribution 

of constituents in sediment along the stream. Concentrations of many inorganic constituents in water 

remained elevated at the farthest downstream site in 

comparison to the reference site in April and Sep-
2 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

tember, indicating that concentrations did not return 

to background concentrations. In April and September, most of the 17 organic compounds detected in 

water, including volatile organic and semivolatile 

organic compounds, were collected in samples near 

the landfill, and most concentrations were below 

their respective reporting limits. Probably because 

of their volatility, few organic compounds were 

detected at sites downstream of that site. A total of 

17 discrete organic compounds were detected in 

sediment samples in either April or September, 

including trichloroethene and tetrachloroethene 

along with their degradation products, 1, 1-dichloroethane and 1,2-dichloroethene; and 4, 4' DDT.

All benthic macroinvertebrate community metrics indicated significantly better conditions at the 

reference site in comparison to the site nearest the 

landfill. At the reference site and at three other sites, 

the taxa collected included several macroinvertebrates that would normally be found under good 

stream-quality conditions; those collected at the site 

near the landfill comprised primarily very tolerant 

macroinvertebrates, including snails, oligochaetes, 

and a pollution-tolerant dipteran.

The reaction of test organisms to samples of the 

water discharged from the PVC pipe showed acute 

toxicity in 10 out of 11 independent tests from 

November 1998 to November 1999. Organism mortality was observed in every acute test at 100-percent sample strength, and a 48-hr LC50 (the lethal 

concentration that causes 50-percent mortality of the 

test organisms after a defined period of exposure) 

was exceeded 89 percent of the time. Chronic toxicological impairment was reported for Ceriodaphnia dubia with survival and reproduction impaired at 

50- and 25-percent concentration of the sample 

water, respectively. No impairment occurred at 12.5-

percent concentration. Overall, the three most notable factors indicating stressed and (or) impacted 

conditions in the stream near the landfill consisted 

of (1) the layer of fine metal oxide precipitate in the 

streambed at and below the site nearest the landfill; 

(2) the significantly depressed numbers of benthic 

macroinvertebrate fauna, particularly of sensitive or 

pollution-intolerant groups; and (3) the consistent 

acute toxicity of water to Ceriodaphnia dubia.

Introduction

After obtaining its operating permit in 1974, the 

Roanoke Regional Sanitary Landfill served as the primary landfill for Roanoke City and County, Va., for 

nearly 20 years, and received a variety of solid wastes, 

including household and business waste, construction 

and wood products, and asbestos-contaminated materials. The approximately 100-acre landfill was capped and 

closed in 1995.

The closed landfill and the Blue Ridge Parkway, a 

roadway and park administered by the National Park Service (NPS), share a common boundary near the base of a 

steep, approximately 40-ft-high embankment at the western edge of the landfill. Near this boundary, a small firstorder stream ("the sampled tributary") originates at the 

base of the embankment and flows west through Parkway lands and beneath the Parkway road before merging 

into the mainstem of an unnamed stream.

The primary source of water to the sampled tributary 

is a 4-in. polyvinyl chloride (PVC) pipe that protrudes 

from beneath the landfill at the base of the embankment. 

Water flows steadily from this pipe into a small pool that 

is the farthest upstream point of the sampled tributary. 

The mainstem of the unnamed stream parallels the Parkway road along its western side, partly within NPS lands, 

and ultimately discharges into the Roanoke River.

In 1995, during routine observations along the Parkway, NPS personnel noted unusual conditions in the sampled tributary relative to similar streams in the area. 

"Yellowboy," an orange-yellow metal-oxide precipitate, 

was observed in the pool and streambed for a number of 

yards rather than the 1 to 3 ft observed in most local 

streams; also noted were unusual colors of algae, bacteria, and (or) flocculent and, at times, a pungent odor. 

Researchers from the Virginia Polytechnic Institute and 

State University (VPI) made preliminary field observations and measurements, and collected water samples 

from the tributary downstream of the landfill to conduct 

toxicological tests. Preliminary results of these tests, 

along with the steady flow of water from the PVC pipe 

and the unusual appearance of the stream, suggested that 

leachate from the landfill could be discharging with the 

ground water into the stream.

The chemical composition of the materials in many 

landfills is not well known. In Virginia, documentation of 

waste that was delivered to individual landfills, including 

chemicals and containers, was not required and enforced 

until the institution of Solid Waste Management regulations in December 1988 (A. Farahmand, Virginia Department of Environmental Quality, written commun., July 
Introduction 3

2001). It is possible that landfill leachate is transported 

with ground water, discharging, and affecting the stream 

system. This possibility has resulted in a concern for the 

health of the sampled tributary and the unnamed stream, 

particularly in lands owned by the NPS and open to the 

public. There also is concern for the potential effects of 

the contents of the landfill downstream of the landfill and 

on the Roanoke River.

In January 1999, NPS and the U.S. Geological Survey (USGS), along with researchers from VPI, entered 

into a cooperative agreement to investigate the effects of 

the closed landfill on the water, streambed sediment, and 

benthic macroinvertebrate community in the first-order 

tributary where the unusual conditions had been 

observed.

Purpose and Scope

This report presents the results of a study of the 

effects of a closed landfill along the Blue Ridge Parkway 

on the water chemistry, the streambed sediment chemistry, and the benthic macroinvertebrate community of a 

first-order tributary that originates from beneath the 

landfill and the unnamed stream into which it flows. 

Water and streambed sediment samples were collected at 

four sites on the unnamed stream and the sampled tributary in April and September 1999. Water samples were 

analyzed for major ions, nitrate, total and dissolved metals, total dissolved solids, total organic carbon, and volatile and semivolatile organic compounds, including 

organochlorine pesticides and polychlorinated biphenyls 

(PCBs). Streambed sediment samples were analyzed for 

total metals, total organic carbon, percent moisture, and 

volatile and semivolatile organic compounds, including 

organochlorine pesticides and PCBs.

Field ecotoxicological measurements were made at 

the four sites sampled for water and streambed sediment 

and at another site on the unnamed stream downstream 

of its confluence with the sampled tributary. At each of 

these five sites, habitat quality was assessed and benthic 

macroinvertebrates were collected and assessed using the 

Rapid Bioassessment Protocols (RBPs) of the U.S. Environmental Protection Agency (USEPA) (Plafkin and others, 1989; Barbour and others, 1999). Water samples 

collected from the 4-in. PVC pipe draining the landfill 

and sediment samples collected downstream from the 

pipe from November 1998 to November 1999 were used 

to test acute and chronic toxicity to laboratory test organisms. 

Description of the Study Area

The study area is within the boundaries of the Blue 

Ridge Parkway, in Roanoke County, near Roanoke, Va. 

(fig. 1). The Parkway is a 469-mi roadway and park 

administered by the NPS, extending from Shenandoah 

National Park in Virginia to Great Smoky Mountains 

National Park in North Carolina along the ridgeline of 

the Blue Ridge Mountains. Throughout most of its 

length, the Parkway boundary extends about 500 yards 

on either side of the road surface. Some areas, however, 

are wider to accommodate public rest areas, historical 

sites, and overlooks.

The study area is in the Blue Ridge Physiographic 

Province of southwestern Virginia, which has been 

described as a "rugged region with steep slopes, narrow 

ridges, broad mountains, and high relief" (Bailey, 1999). 

The study area is underlain by rocks of Middle Proterozoic age and is near the western edge of the Blue Ridge 

Thrust Sheet. The underlying geologic units include layered gneiss and granulite. Soils in the area are naturally 

iron-rich; within a few miles of the closed landfill are 

units of metasandstone and sandstone that have been 

mined extensively for iron (Henika, 1997).

Geologic structure, topography, and lithology control 

the occurrence and flow of ground water in the Blue 

Ridge Physiographic Province. The rocks underlying the 

thin soil layer are relatively impermeable except where 

fractured or weathered. Contact zones between different 

rock types, however, may accumulate water in some 

areas. Openings that provide ground-water storage in 

these rocks usually occur within a few hundred feet of 

the surface, although a thin layer of saprolite, or weathered rock, also may provide near-surface ground-water 

storage (State Water Control Board, 1988; David Nelms, 

U.S. Geological Survey, written commun., 2000). Small 

streams in this area tend to have stone substrates edged 

with boulder and rock, resulting in rocky riffle and cascade areas. The cascade areas are interspersed with pools 

where silt and sand collect.

Ground-water storage is limited in the Blue Ridge, 

and ground-water recharge and resultant discharge occur 

at a relatively fast rate. Age-dating studies of ground 

water in the Blue Ridge Physiographic Province north of 

the study site have shown that water discharging from 

springs near the crest of the Blue Ridge Mountains is of 

nearly modern age, from 0 to 2 years old, under wet and 

dry conditions. Samples collected from springs at 

Shenandoah National Park during a drought were only 

slightly older than those collected during years with nor
4 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Figure 1. Location of study area, the Blue Ridge Parkway, and physiographic provinces of Virginia.

APPALACHIAN 

PLATEAU

VIRGINIA

TENNESSEE NORTH CAROLINA

Sinking

Creek ROANOKE

COUNTY

BEDFORD

COUNTY

GILES

COUNTY

Great Smoky Mountains 

National Park

BLUE

RIDGE

PARKWAY

Chesapeake

ATLANTIC OCEAN

Bay

Shenandoah

National Park

STUDY AREA

Roanoke

River

Roanoke COASTAL PLAIN

PIEDMONT

BLUE RIDGE

VALLEY AND RIDGE

35o

37o

39o

84

o

82

o

80

o

78

o

76o

0 20 40 60 80 100 KILOMETERS

0 20 40 60 80 100 MILES

Base from U.S. Geological Survey, 1:2,000,000 Digital Line Graph

Physiographic provinces from U.S. Geological Survey, 1:2,000,000 Digital Line Graph

Blue Ridge Parkway from U.S. Department of Census, 1:100,000 TIGER files; U.S. Geological

 Survey, 1:24,000, 7.5-minute quadrangles; and U.S. Geological Survey, 1:100,000 Half panel

 quadrangles

Shenandoah National Park boundary from U.S. Geological Survey, 1:24,000, 7.5-minute quadrangles

Great Smoky Mountains National Park boundary from U.S. Geological Survey, 1:24,000, 7.5-minute quadrangles

Universal Transverse Mercator 17 projection, NAD 27, central meridian 81

o

00'W
Introduction 5

mal rainfall (Nelms and others, 1999; Plummer and others, 1999).

The topography of the closed Roanoke Regional Sanitary Landfill closely resembles that of the naturally 

broad, flat hills in this area. Near the landfill, the altitude 

ranges from more than 800 ft along the Roanoke River to 

near 1,200 ft at the highest point of the landfill. The 

closed landfill and the Blue Ridge Parkway share a common boundary (fig. 2), near the base of an approximately 

40-ft-high embankment at the west edge of the landfill.

The landfill and the basin of the unnamed stream 

sampled in this study are shown on the Roanoke, Stewartsville, Garden City, and Hardy, Va., USGS 7.5-minute 

topographic maps. Neither the unnamed stream nor its 

tributaries are shown on the topographic maps as either 

perennial or intermittent streams. However, all of these 

streams were flowing during state-wide drought conditions during the study period and during previous years 

and were therefore judged to be perennial.

Sampling was conducted downstream of the landfill 

in a first-order stream that originates at the base of the 

embankment at the western boundary of the landfill and 

flows approximately 0.2 mi west on Parkway land and 

through a culvert beneath the Parkway road. West of the 

Parkway road, the first-order tributary discharges into the 

mainstem of an unnamed stream, which flows north 

another 0.2 mi prior to discharging to the Roanoke River 

about 0.1 mi upstream (west) of the Blue Ridge Parkway 

Bridge. Sampling was also conducted on the unnamed 

stream. The length of the sampled tributary from the 

landfill boundary through NPS lands to where the 

unnamed stream discharges to the Roanoke River is 

approximately 0.4 mi. A reference site was chosen on the 

unnamed stream upstream of the confluence with the 

sampled tributary; another reference site, from which 

water and sediment samples were collected, was on 

Sinking Creek in Giles County, Va. There are no other 

tributaries to the unnamed stream downstream of its confluence with the sampled tributary.

The principal source of water to the sampled tributary 

is a 4-in. polyvinyl chloride (PVC) pipe at the western 

boundary of the landfill that protrudes from beneath the 

landfill at the base of the embankment (fig. 3). The water 

from the 4-in. pipe flows directly into a small pool from 

which the sampled tributary originates. When asked 

about the pipe in 2000, landfill personnel recalled that a 

series of "spring boxes" had been produced at the periphery of the landfill when it was first constructed to provide outlets for known springs in the area (Katherine 

Glass, Virginia Department of Environmental Quality, 

personal commun., 2000). This 4-in. PVC pipe is one of 

several outlets subsequently found by Virginia Department of Environmental Quality (DEQ) personnel along 

the perimeter of the landfill. Other sources of water to 

the sampled tributary include intermittent ground-water 

seeps along the western boundary of the landfill embankment and ground water discharging from stream banks. 

In addition, in periods of high precipitation, excess water 

from a sedimentation pond near the western boundary of 

the landfill is channeled over the embankment via an 

overflow pipe to an approximately 1-ft-diameter galvanized tin pipe from which the water flows into the pool 

and the channel of the sampled tributary.

Background Information

Wastes in landfills undergo physical changes such as 

compaction and fragmentation, and chemical changes 

such as microbially mediated degradation. The rate of 

degradation of landfill waste is controlled by its composition, degree of compaction, and water content, and by 

the conditions within the landfill, such as availability of 

oxygen, internal temperature, and inhibitory substances 

such as bactericidal chemicals. In sanitary landfills, 

where wastes are compacted and covered with soil, 

chemical oxidation and the action of aerobic microbes 

quickly deplete oxygen. As oxygen availability 

decreases and the environment within the landfill 

becomes anaerobic, the rate of waste degradation also 

decreases.

By-products of the early stage of anaerobic degradation in a landfill include carbon dioxide and organic 

acids, substances that decrease pH and thereby promote 

dissolution of many inorganic materials. At this stage, 

landfill conditions are characterized by low pH (4.0 to 

5.0 units) and high specific conductance, high metals 

content, and high chemical-oxygen demand. In the later 

stage of anaerobic degradation, methanogenic bacteria 

produce methane by utilizing carbon dioxide and hydrogen ions, resulting in an increased pH (7.0 to 8.0 units). 

At this stage, chemical-oxygen demand and specific conductance are moderate (Ferrell and Smith, 1995). At any 

one time, wastes in various parts of a landfill can be in 

different stages of decomposition.

Leachate, the liquid produced by solid waste in landfills, is generated by percolation of water through the 

contents of the landfill, and its chemical characteristics 

parallel the stage of decomposition of the landfill. 

Leachate formed in the early anaerobic stage is characterized by a low pH, high specific conductance, and high 

concentrations of organic compounds and dissolved metals; the later anaerobic stage also has a low pH, high 
6 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Figure 2. Sampling sites near Blue Ridge Parkway and a closed landfill, Roanoke County, Virginia.

BLUE

RIDGE

PARKWAY

BLUE RIDGE PARKWAY BOUNDARY

SAMPLING SITE AND NUMBER ON UNNAMED STREAM

SAMPLING SITE AND NUMBER ON SAMPLED TRIBUTARY

MONITORING WELL AND NUMBER

USGS GAGING STATION 02056000

BASIN BOUNDARY FOR UNNAMED STREAM 

APPROXIMATE BOUNDARY OF CLOSED LANDFILL

618

658

618

Niagara Power Plant Dam

Sedimentation pond

79o53'

37

o

15'60"

79o

52'

37

o

14'60"

0 0.25 0.5 0.75 1 MILE

0 0.25 0.5 0.75 1 KILOMETER

1,3-BC, 4

MW-2

EXPLANATION

2, 3

Niagara

ROANOKE COUNTY

BEDFORD COUNTY

4

1

3-BC

MW-2

3

2

Base from U.S. Geological Survey, 1:100,000 Digital Line Graph

Hydrography from U.S. Geological Survey, 1:100,000, 

 7.5-minute quadrangles

Roanoke

River

Universal Transverse Mercator 17 projection, NAD 27, 

 central meridian 81

o

00'W
Introduction 7

Figure 3. Pool at base of closed landfill, at origin of sampled tributary (site 2), showing 4-inch polyvinyl chloride (PVC) 

pipe and overflow pipe (A), and the sampled tributary, looking downstream from site 2, facing west (B), 

near Roanoke, Virginia.

(A)

(B)

4-INCH PVC PIPE
8 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

organic acid concentration, and high specific conductance, but has lower concentrations of metals (Ferrell and 

Smith, 1995).

In this area of the Blue Ridge, soils are naturally ironrich. When iron-rich, low-oxygen ground water comes 

into contact with oxygen at land surface, iron and other 

metal constituents oxidize and precipitate out into a 

receiving stream, producing yellowboy. Yellowboy is a 

general term that may include not only the metal oxide 

precipitate (ferric hydroxide, for example), but also bacteria, algae, and (or) other organic matter, which combine 

to create the yellowish-red flocculent in the stream.

Yellowboy is found in many areas of the United 

States where low-oxygen, metal-rich ground water is discharged to land surface, and commonly occurs in this 

area of the Blue Ridge. Beginning in 1995, however, yellowboy was observed frequently in the pool and streambed near the landfill for a number of yards rather than the 

1 to 3 ft observed in most local streams. Unusual colors 

and forms of sheathed bacteria were observed in the 

pool, including a genus of bacteria (Sphaerotilis) associated with waters of high organic content. These bacteria 

commonly create problems at wastewater treatment 

plants by impeding water flow in discharge canals. 

Previous Investigations

Waste was no longer accepted at the landfill beginning May 1994, and capping and closure were completed 

in January 1995. In accordance with requirements of the 

DEQ Department of Waste Management, air vents and 

ground-water monitoring wells were installed at the landfill to monitor air and water quality. Currently (2003), an 

environmental contractor samples the monitoring wells 

once every six months, and air quality is monitored more 

frequently. Previous investigators analyzed gas emissions 

from the landfill (Marshall Miller and Associates, 1995, 

1996) and assessed potential hazards associated with 

soils and facilities areas at the landfill (Professional Service Industries, Inc., 1991).

Results of ground-water monitoring showed inorganic and organic constituents in downgradient wells, 

including MW-2, the monitoring well nearest to the sampled tributary (Virginia Department of Environmental 

Quality, unpub. data, 2000) (fig. 2). Constituents frequently detected in samples collected from MW-2 

between May 1996 through May 2000 include the metals 

cadmium, chromium, mercury, and zinc; and organic 

compounds benzene, delta-BHC, chloroethane, 2,4-

dichlorophenoxyacetic acid, p-dichlorobenzene, 1,1-

dichloroethane, cis-1,2-dichloroethene, methyl chloride, 

methylene chloride, tetrachloroethene, trichloroethene, 

vinyl chloride, and o-xylene. Of these constituents, the 

laboratory and industrial compounds methylene chloride, 

tetrachloroethene, trichloroethene, and vinyl chloride 

were detected at concentrations exceeding the USEPA 

maximum contaminant level for drinking water in all 

samples collected. Benzene concentrations exceeded the 

USEPA maximum contaminant level for drinking water 

in all but the May 2000 sample.

The potential effects of the landfill on the water 

resources of Blue Ridge Parkway lands were not investigated until 1996, when a preliminary study was completed for the NPS by VPI researchers (Cherry and 

Currie, 1996). As part of this reconnaissance investigation, general water chemistry and trace-element concentrations were evaluated, and possible toxicity of the water 

from the unnamed stream was investigated. Results 

included a 45-percent mortality of a water flea (Ceriodaphnia dubia) exposed to water samples collected 

from the stream and significant chronic reproductive 

impairment to the water flea Daphnia magna, which was 

exposed to streambed sediment samples from the same 

area. Concentrations of zinc in bed sediments of the 

unnamed stream were elevated relative to those in sediments from a background site. Findings from this study 

indicated the need for further investigation of the potential effects of the closed landfill on the water resources of 

Blue Ridge Parkway lands and adjoining lands (Cherry 

and Currie, 1996).

Numerous studies have described the chemical characteristics of landfill leachates, including nutrient content, organic and inorganic composition, and 

microbiology, but relatively few studies have characterized leachate toxicity (Cameron and Koch, 1980; Plotkin 

and Ram, 1984). Cameron and Koch (1980) reviewed 

landfill toxicity data obtained from bioassays utilizing 

rainbow trout (Salmo gairdneri, or Oncorhynchus 

mykiss) and concluded that landfill leachates usually are 

highly toxic to this species. A specific conclusion was 

that leachates are highly toxic within the confines of 

landfills and usually remain so at the point of discharge 

from the landfill despite dilution that might occur prior to 

that point from surface runoff and ground water. Plotkin 

and Ram (1984) tested the toxicity of a sanitary landfill 

leachate and found the leachate to be highly toxic to Photobacterium phosphorium, moderately toxic to Daphnia 

magna, and slightly toxic to Pimephales promelas (fathead minnow). Selenastrum capricornutum (a freshwater 

alga) growth was inhibited at exposure to a solution of 

10-percent leachate, but cells recovered after centrifuga-
Study Design and Methods 9

tion and reinoculation into algal nutrient medium (Plotkin and Ram, 1984).

Acknowledgments

In this effort, technical assistance was provided by 

Tom Davis and Bambi Teague, NPS. The authors also 

acknowledge Richard J. Ahlin and John M. Gearheart, 

USGS, for their experienced and focused sampling 

efforts. Mitchell Harris, Terrence Messinger, and Marty 

Gurtz are thanked for their technical reviews of this 

report.

Study Design and Methods

This study was divided into two components: the first 

component consisted of analysis of water and streambed 

sediment samples and measurements of stream discharge 

at each of four sites on the sampled tributary and the 

unnamed stream (sites 1, 2, 3, and 4). Water samples 

were analyzed for major ions, nitrate, total and dissolved 

metals, total dissolved solids, total organic carbon, and 

volatile and semivolatile organic compounds, including 

organochlorine pesticides and polychlorinated biphenyls 

(PCBs). Streambed sediment samples were analyzed for 

total metals, total organic carbon, percent moisture, and 

volatile and semivolatile organic compounds, including 

organochlorine pesticides and PCBs. Ground-waterquality data that had been provided to the DEQ Waste 

Management Division, and which showed the presence 

of inorganic and organic constituents in monitoring wells 

near the western boundary of the landfill, were used to 

determine potential groups of compounds for analysis.

Laboratory analyses for both water and streambed 

sediment samples were performed by Quanterra Environmental Services, Denver, Co. All containers for shipping sediment or water samples to the laboratory were 

washed, rinsed, and quality-assured by the contract laboratory, and preservatives were added prior to being sent 

to the USGS Virginia district office in Richmond, Va. 

The prepared containers were delivered to the USGS 

office within guidelines of chain-of-custody procedures.

Analytical results were provided to the investigators 

in a hard-copy report, which included a discussion of any 

anomalies observed during the analysis, a tabulation of 

analyses, a summary of all quality-control samples associated with the field samples, and a raw data set suitable 

for independent validation.

The second component of the study consisted of biological and toxicological analyses at each of the four 

sites sampled for water and streambed sediment, and 

benthic macroinvertebrate sampling at these four sites 

and one additional site on the unnamed stream. These 

analyses included (1) an assessment of stream habitat 

and measurements of the composition of the benthic 

macroinvertebrate community using the Rapid Bioassessment Protocols (RBPs) of the USEPA (Plafkin and 

others, 1989; Barbour and others, 1999) and (2) tests of 

acute and chronic toxicity. Toxicity tests quantitatively 

measure the survival or reproductive rate of test organisms in a particular environmental medium. Sediment 

toxicity testing was performed on samples collected at 

sites 1, 2, 3, and 4. In addition, water column toxicity 

testing was performed from samples collected from the 

PVC pipe draining the landfill at site 2. Both 48-hr acute 

and 7-day chronic toxicity tests of water collected from 

the PVC pipe were performed using selected laboratory 

test organisms, as were the two 10-day chronic toxicity 

tests of streambed sediments.

Sampling had been planned for two seasons, during 

what were anticipated to be periods of high base-flow 

(February, March or April) and low base-flow (July, 

August, or September) conditions. Prior to all but one 

sampling event, no substantial rainfall had occurred for 

several weeks. In September 1999, a storm occurred two 

days prior to sampling; however, near-base-flow conditions were re-established prior to sample collection on 

September 8. Water, streambed sediment, and benthic 

macroinvertebrate samples collected in April and September 1999 thus were considered to be under steadystate flow conditions.

Site Selection

Sampling sites for chemical and biological analyses 

were selected on the basis of their location within the 

watershed with respect to water sources to the unnamed 

stream, and by the appropriateness of the site for either 

water-and-sediment chemistry or biological sampling 

(fig. 2, table 1). The four sites that were selected 

included a reference site along the mainstem of the 

unnamed stream (site 1); two sites along a first-order 

tributary to the unnamed stream (the "sampled tributary"), one directly downstream of the landfill (site 2) 

and the other downstream of the Blue Ridge Parkway 

(site 3); and a site downstream of the confluence of the 

unnamed stream and the sampled tributary, the site closest to the Roanoke River (site 4). Benthic macroinvertebrate samples were collected at these four sites and at 

another site (site 3-BC, "below confluence") that was 

chosen to provide ecological information downstream 
10 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

from the confluence of the unnamed stream and the sampled tributary. The unnamed stream is a second-order 

stream throughout its sampled length, from the reference 

site (site 1) to where it discharges into the Roanoke 

River.

All samples for a sampling event were collected on 

the same day. Samples were collected beginning at the 

site farthest downstream (site 4) and working upstream 

(3 or 1, then 2) to prevent streambed disturbance or contamination from upstream. At each site, water samples 

were collected first, while field measurements were made 

and discharge was measured; then streambed sediment 

samples were collected; benthic macroinvertebrates were 

collected last.

A site on Sinking Creek was used as an independent 

reference site for the purpose of comparing the growth 

and toxicity of benthic macroinvertebrates from this 

study with other benthic macroinvertebrate data sets. 

Sinking Creek is in the rural area of Giles County, Va. 

(fig. 1), and has been used for the past 10 years by the 

ecotoxicology laboratory at VPI to provide water and 

streambed sediments for benthic macroinvertebrate studies. Water and streambed sediment samples obtained 

there have produced little or no deleterious effects on 

benthic macroinvertebrates in toxicity tests. In addition, 

Sinking Creek water was used as a second water source 

for the cultivation of test organisms and as an additional 

reference site for all toxicity tests in this study.

Water Chemistry

Samples were collected by USGS personnel using 

preparation, sampling, processing, and shipping methods 

as documented in Wilde and others (1997, 1998, 1999). 

All streams from which water samples were collected 

were small enough to assume that they were well mixed 

so that depth- and width-integrated samples were unnecessary. Water samples were analyzed for major ions, total 

and dissolved metals, nitrate, total dissolved solids, total 

organic carbon, and volatile and semivolatile organic 

compounds, including organochlorine pesticides and 

PCBs.

Because the water in a stream moves rapidly relative 

to movement of sediment and the biota, the stream sample provides a single, instantaneous view of the conditions and chemical composition of the stream at the time 

Site Station name

and location

USGS

station

number

Site description

Sample type collected

Water Streambed 

sediment

Benthic 

macroinvertebrates

Site 1

Roanoke River tributary 1 

below Rt. 618 at Niagara, 

Va.

0205599710

Reference site on unnamed 

stream, upstream of confluence 

with sampled tributary

XX X

Site 2

Roanoke River tributary 1 

to tributary 1 above Parkway at Niagara, Va. 0205599730 Sampled tributary, at outflow 

pipe from closed landfill XX X

Site 3

Roanoke River tributary 1 

to tributary 1 at Niagara, 

Va.

0205599740

Sampled tributary, west of Blue 

Ridge Parkway and upstream of 

confluence with unnamed 

stream

XX X

Site 3-BC

Roanoke River tributary 1 

below confluence with tributary 1 below Rt 618 at 

Niagara, Va.

n.a.

Unnamed stream, downstream 

of confluence with sampled 

tributary

 n.a. n.a. X

Site 4 Roanoke River tributary 1 

at mouth at Niagara, Va. 0205599760

Unnamed stream at farthest 

downstream point, approaching 

Roanoke River

XX X

Sinking 

Creek

Sinking Creek reference 

site n.a.

Reference site, adjacent to 

Route 42 near Route 460, near 

Newport, Va.

XX X

Table 1. Sites sampled for the study of an unnamed stream and its tributary near the Blue Ridge Parkway, Roanoke County, Virginia

[See fig, 2 for site locations; n.a., not applicable]
Study Design and Methods 11

of sampling. The instantaneous data have limited applicability, however, because stream chemistry can be 

affected by many variables, including the prevailing 

weather, seasonal changes, ambient temperature, any 

effects of recent precipitation, the preceding and current 

streamflow conditions, the geology of the immediate 

area, and chemical and biologic processes in the stream. 

Repeated field and laboratory analyses may be able to 

account for changes in conditions affecting stream chemistry over time. Because this study was limited to two 

sampling events, however, any changes noted in seasonal 

and temporal data may not constitute a trend.

Stream discharge was measured near the four waterchemistry sites to determine the amount and relative 

location of ground-water discharge and surface water 

inflow to the stream. Discharge was measured using a 

Price pygmy flow meter. Established streamflow measurement procedures for small, rocky streams were used 

(Rantz and others, 1982). Discharge was measured 

within 20 ft of each sampling site. Air and water temperature, dissolved oxygen, pH, and specific conductance 

were measured in the center-of-flow of the stream at 

each site. A Yellow Springs Instruments (YSI) multiparameter meter was used to make field measurements.

Water samples analyzed for major ions, total metals, 

nitrate, total dissolved solids, total organic carbon, and 

volatile and semivolatile organic compounds were collected directly into laboratory-prepared sample bottles. 

Samples analyzed for total organic carbon were collected 

into baked amber glass bottles and preserved with sulfuric acid to a pH less than 2. Samples for semivolatile 

organic compounds, including pesticides and PCBs, 

were collected into baked amber glass bottles. Samples 

for volatile organic compounds (VOCs) were collected in 

sets of three 40-mL vials and preserved with hydrochloric acid.

Samples analyzed for total metals were collected into 

acid-rinsed polyethylene bottles. Water from which "dissolved" (filtered) metals were to be analyzed was collected from the stream into an acid-rinsed Teflon holding 

bottle and filtered from the holding bottle into acidrinsed polyethylene bottles. A single-use 0.45-μm-poresize capsule filter was used to filter the sample. Both 

total and dissolved metals were preserved with nitric acid 

to a pH less than 2.

Filtration into sample bottles was completed as soon 

as possible after sample collection, usually within 15 

minutes. All filled sample bottles were chilled to 4oC 

immediately upon completion of processing. Prior to 

overnight shipment to the laboratory, samples were 

repacked in fresh ice and sealed.

Streambed Sediment Chemistry

Sediment is fragmental material derived primarily 

from the disintegration of rocks from the earth's crust 

and can range widely in terms of particle size, shape, 

specific gravity, and mineral composition (Edwards and 

Glysson, 1999). Within a stream, sediment is a major 

repository for the more persistent chemicals, including 

some pesticides and PCBs, which may be introduced 

into surface waters (Ingersoll and others, 1995). Streambed samples were collected from a range of depositional 

areas at each site, including pools, along stream margins, 

and in riffle areas. Areas where fine-grained streambed 

sediment was deposited were preferentially sampled over 

areas of coarse sediment; constituents adsorbed onto sediments tend to be concentrated in the finer sediment 

because of the larger surface area. Care was taken to disturb the stream as little as possible to minimize effects on 

stream chemistry and biological conditions immediately 

downstream. Because the streams were relatively free of 

leaves and other organic matter, sieving of the sediment 

was not necessary.

Although fine-grained areas were targeted, the 

streambed sediment at sites 1, 3, and 4 was limited to silt 

and sand collected from small pools in the sampling 

area, and some larger grained sediments also were 

included in the samples. In contrast, at site 2, the streambed sediment was several inches of a silt/mud/precipitate 

mixture, which was easily suspended in water. As samples were collected, the sediment/precipitate was 

allowed to settle as much as possible before the water 

was decanted and the sediment sample collected. The 

final sample resembled a silty slurry.

Streambed sediment samples were collected at each 

stream site using Teflon scoops. Samples were composited in a large, clean glass bowl, homogenized, and distributed into clean wide-mouthed containers for analysis 

by the laboratory, and into clean plastic bags for toxicity 

testing by VPI. Samples analyzed for total organic carbon were preserved with sodium bisulfite. All streambed 

sediment samples were chilled to 4oC. Samples were 

analyzed for total metals, total organic carbon, percent 

moisture, and volatile and semivolatile organic compounds, including organochlorine pesticides and PCBs. 

VPI researchers used subsamples of the streambed sediments to analyze toxicity of the sediment to laboratory 

organisms.
12 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Ecological Sampling and Toxicity Testing

Field and laboratory ecotoxicological measurements, 

including routine water chemistry and field measurements, a volumetric estimate of flow, an assessment of 

habitat quality, and collections of benthic macroinvertebrates were done at sites within the sampled tributary and 

unnamed stream. Several 48-hr acute tests, one 7-day 

chronic test of the leachate to Ceriodaphnia dubia (a 

water flea), and two 10-day chronic sediment toxicity 

tests were conducted with Chironomus tentans (a midge) 

and Daphnia magna (a water flea). Water samples for 

ecotoxicological analyses were collected periodically 

from the PVC pipe at site 2 between November 1998 and 

November 1999 (table 2). These samples provided background field measurements and were used to determine if 

toxicity from the water occurred intermittently or consistently.

Benthic Macroinvertebrates

The use of benthic macroinvertebrates as biological 

indicators is the cornerstone of many water-quality 

assessments. The importance of invertebrates in biological monitoring is demonstrated by the development of 

the USEPA RBPs by Plafkin and others (1989), and Barbour and others (1999), and by the Ohio Environmental 

Protection Agency’s (OEPA) development of the Invertebrate Community Index (Ohio Environmental Protection 

Agency, 1988, 1989).

VPI researchers collected benthic macroinvertebrates 

in April and September 1999 at sites 1, 2, 3, 4, and 3-BC, 

using a combination of the methods described in the 

USEPA RBPs (Plafkin and others, 1989; Barbour and 

others, 1999) and OEPA (1988, 1989) guidelines, with 

some modifications. Organisms were collected from the 

natural substrate using D-frame nets with 800-μm mesh 

and forceps to remove organisms from the net. Benthic 

macroinvertebrates were collected for a minimum of 20 

minutes per sample, and collection continued until no 

new taxa were observed in gross examination. Sampling 

effort is assumed to be consistent among sites and 

between sampling teams. Four replicates were collected 

at each site; each replicate sample was a composite that 

included, whenever possible, a pool, riffle, margin, and 

run area. An attempt was made to sample similar habitats 

at each site. Macroinvertebrates on rocks and pebbles as 

well as in sand, silt, and leaf packs were collected. Samples were preserved initially with 70-percent ethanol in 

the field and transported to the laboratory at VPI for sort

Date Field 

measurements

Benthic macroinvertebrates

Water Streambed 

sediment

48-hour

acute toxicity

7-day

chronic toxicity 

(survival and 

reproduction)

10-day

chronic

toxicity

11/29/98 X – X – –

12/9/98 X – – – –

1/26/99 – – X – –

2/18/99 X – X – –

2/19/99 X – – – –

3/12/99 X – X – –

*4/26/99 X X – – X

6/18/99 X – X – –

7/24/99 X – X – –

7/30/99 X – X – –

7/31/99 – – – X –

8/2/99 X – – – –

8/26/99 X – X – –

9/6/99 X – X – –

*9/8/99 – X – – X

10/14/99 X – X – –

11/28/99 X – X – –

Table 2. Schedule of field measurements made at all sites, and benthic macroinvertebrate, water, and streambed 

samples collected for ecotoxicological assessment at site 2, near the Blue Ridge Parkway, Roanoke, Virginia

[–, not collected or measured; *, indicates collection date of water and sediment samples]
Study Design and Methods 13

ing and identification. In the laboratory, samples 

were washed with water and stored in 70-percent ethanol. Prior to identification and enumeration, samples 

were sieved through a 500-μm mesh and rinsed. Macroinvertebrates were identified to the lowest practical taxonomic level following taxonomic keys by Pennak (1989), 

Merritt and Cummins (1996), and Wiggins (1996). No 

subsampling was necessary due to the small number of 

organisms obtained.

On the basis of the organisms identified, nine benthic 

macroinvertebrate community metrics were evaluated 

statistically, with four replicates taken per station. The 

metrics evaluated were total abundance, taxa richness, 

caddisfly abundance, stonefly abundance, mayfly abundance, percent mayfly abundance, Ephemeroptera/Plecoptera/Trichoptera (EPT) abundance, percent EPT 

abundance, and EPT richness.

Statistical analysis of the summary metrics for 

benthic macroinvertebrates was performed using the Statistical Analysis System (SAS) developed by the Statistical Analysis System Institute, Inc. (1996). Data were 

analyzed for normality using the Shapiro-Wilk Test for 

normality (α=0.05). Data that were distributed significantly differently than normal were transformed to meet 

assumptions of normality. The data were square-root 

transformed with percentages using an arcsine square 

root transformation. A parametric analysis of variance 

(ANOVA, α=0.05) was conducted on normally distributed data, while a nonparametric ANOVA (NPAR1Way 

(Kruskal-Wallis), α=0.05) was used to analyze data that 

did not meet the assumption of normality either before or 

after data transformation (U.S. Environmental Protection 

Agency, 1993; Hollander and Wolfe, 1973). A Least 

Squares Difference (LSD) multiple comparison (α=0.05) 

was conducted on ranked data to determine whether 

there were statistically significant differences among the 

four stations. Raw benthic macroinvertebrate identification data are found in Appendixes 5 and 6.

Habitat Assessment

The USEPA's RBPs were used to conduct habitat 

assessments at the five sites sampled for benthic macroinvertebrates and also at Sinking Creek, the reference 

site, prior to field data collection. Habitat is a major 

determinant of aquatic community potential, with both 

the quality and quantity of available habitat affecting the 

structure and composition of resident biological communities (Plafkin and others, 1989). The RBPs assess differences in habitat quality that are attributed to bank erosion 

and channel sedimentation, processes that indirectly 

influence water quality.

Habitat is assessed by means of nine metrics within 

three categories–substrate and instream cover, channel 

morphology, and riparian and bank structure (table 3). 

The habitat metrics, which are evaluated on the basis of 

habitat use by aquatic life, are used to identify potential 

sources of limitation to the aquatic biota. Sites are rated 

from Excellent to Poor, depending upon the scores for 

each metric (Plafkin and others, 1989).

 Habitat Metric

Rating

Poor Fair Good Excellent

Primary-Substrate and Instream Cover

1. Bottom substrate and available cover 0-5 6-10 11-15 16-20

2. Embeddedness 0-5 6-11 11-15 16-20

3. Flow/velocity 0-5 6-12 11-16 16-20

Secondary-Channel Morphology

4. Channel alteration 0-3 4-7 8-11 12-15

5. Bottom scouring and deposition 0-3 4-7 8-11 12-15

6. Pool/riffle, run/bend ratio 0-3 4-7 8-11 12-15

Tertiary-Riparian and Bank Structure

7. Bank stability 0-2 3-5 6-8 9-10

8. Bank vegetation 0-2 3-5 6-8 9-10

9. Streamside cover 0-2 3-5 6-8 9-10

Minimum to Maximum Possible Score 0-30 39-66 75-102 111-135 

Table 3. Habitat assessment metrics and possible rating for each metric (Plafkin and others, 1989; Barbour and others, 1999)
14 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Field Measurements

Field measurements were made under different flow 

conditions at site 2 between November 1998 and November 1999 during trips to collect water for use in acute and 

chronic toxicity testing. Field measurements also were 

made prior to each biological sampling event. Those 

measurements included temperature, specific conductance, DO, pH, and alkalinity. DO was measured using a 

YSI Model 55 oxygen meter; specific conductance and 

temperature were measured using an Orion Model 122 

specific conductance meter. A Fisher Scientific Accumet 

1001 with a combination electrode was used to measure 

pH. The three meters were calibrated and used following 

standard operating procedures provided by the manufacturer. Alkalinity was determined at the laboratory with a 

standard titration method to pH 4.5, using bromocresol 

green as the indicator.

Toxicity Testing

Laboratory toxicity testing consisted of acute and 

chronic water column and chronic sediment toxicity 

tests. Laboratory toxicity testing has been used extensively for the past 50 years, and specific guidelines and 

protocols have been developed to provide reliable and 

accurate data (U.S. Environmental Protection Agency, 

1993, 1994; American Society for Testing and Materials, 

1995).

Water Column Acute and Chronic

The objective of acute toxicity testing is to determine 

the concentration of a test material (for example, a chemical or effluent) or the value of a chemical measurement 

(for example, temperature or pH) that produces a deleterious effect on test organisms during a short-term exposure under laboratory conditions (Parrish, 1985). Acute 

toxicity test results are reported in terms of LC50, the 

concentration at which 50 percent of the test organisms 

die during a defined exposure period. Acute toxicity tests 

with C. dubia were analyzed by the Connecticut Department of Environmental Protection's CT-TOX program to 

determine LC50 values using the Spearman-Karber 

method (Connecticut Department of Environmental Protection, 1990).

Acute water column testing was conducted with C. 

dubia, less than 24 hrs old, following USEPA (1993) protocols. Five ceriodaphnids were used per replicate with 

four replicates per concentration. Testing was done with 

a control of moderately hard synthetic water (EPA100) 

and five concentrations based on a 0.5 serial dilution 

starting at 100 percent. Survivorship was the endpoint 

value determined after 48 hours. Water samples for use in 

toxicity testing were collected in November and December 1998 and in January, February, March, April, June, 

July, August, September, October, and November 1999. 

All samples were collected from the PVC pipe draining 

the landfill at site 2.

Chronic toxicity tests are used to determine whether 

impairment of test organism growth and reproduction 

occurs in waters or sediments that do not cause acute toxicity. Such impairment would indicate disruption of ecological integrity and the subsequent loss of invertebrate 

community populations from impacted fresh waters 

(Nebeker and others, 1984). In this report, chronic toxicity endpoint values for water samples are survival, 

expressed as percent survival of test organisms, and 

reproduction, expressed as mean number of young (neonates) produced.

Chronic water column testing also used C. dubia, less 

than 24 hrs old, following USEPA (1994) protocols. 

Moderately hard synthetic water (EPA100) was used as 

test diluent. Testing consisted of a control with five concentrations of leachate based on a 0.5 serial dilution starting at 100 percent. Chronic toxicity tests were conducted 

for 7 days or until 60 percent of the control organisms 

had their third brood of offspring.

Sediment

Nebeker and others (1984) first described general 

methods for conducting toxicity tests with sediments 

using invertebrates. The water flea Daphnia magna and 

the midge Chironomus tentans are the most frequently 

used test organisms to evaluate toxicity of freshwater 

sediments (Doi, 1998). Daphnia generally have been 

shown to be the most sensitive organisms used for sediment tests, especially to metals, while midges maintain 

intimate contact with and burrow into the sediment and 

may be sensitive to toxic organic chemicals (Nebeker and 

others, 1984). Standard methods for conducting toxicity 

tests using both D. magna and C. tentans have been 

developed (American Society of Testing and Materials, 

1995; Environmental Protection Agency, 1994).

Streambed sediment samples were collected from 

depositional areas at each site; approximately 500 g of 

sediment from each site were placed into a sterile plastic 

bag that was returned to the VPI laboratory on ice, and 

then refrigerated at 4°C for up to two weeks before testing. Sediment toxicity tests using whole organisms were 

conducted with D. magna and C. tentans, with survival, 
Study Design and Methods 15

growth, and reproduction as endpoints. Testing protocols 

followed those described by the American Society of 

Testing and Materials (1995) and USEPA (1994).

Testing with D. magna consisted of the placement of 

one daphnid, 5 days old, into a 50-ml beaker with 

approximately 10 ml (by volume) of sediment and 30 ml 

of site water. Site water was used in the sediment toxicity 

tests instead of reference water to simulate environmental conditions and to prevent dilution of sediment toxicity 

by the reference water. The overlaying water was 

renewed each day by siphoning and refilling. Daphnia

were fed, observed, and checked for survival and reproduction daily. Eight replicates were used per site, and an 

additional control was added with Sinking Creek water 

and sediments.

Chironomus testing was conducted by placing ten 8-

day old midge larvae into a 600-ml glass beaker with 100 

g (by weight) of sediment and 400 ml of overlaying site 

water, with five replicates per site. Overlaying water in 

the beakers was renewed each day. Midges were also fed 

and observed over 10 days for survival and growth. All 

sediment tests required aeration due to the anaerobic 

conditions of some of the sediments.

Sediment toxicity test endpoint values included survival, reproduction, and growth, expressed as mean 

weight. Sediment toxicity test results were analyzed 

using recommended USEPA guidelines (1994). All survival, reproduction, and growth data were tested for normality (Shapiro-Wilk test for normality, α=0.05) and 

then analyzed using the appropriate parametric or nonparametric statistical tests (one-way parametric ANOVA 

or NPAR1Way ANOVA, α=0.05).

Quality Assurance and Quality Control

Quality assurance (QA) and quality control (QC) 

measures were implemented to ensure that data were 

obtained using appropriate methods and were of known 

precision, accuracy, and completeness. QA measures 

included using established procedures for the preparation 

of field equipment and collection and preservation of 

samples; adhering to consistent individual sampling 

responsibilities; using procedures that minimize crosscontamination of samples; and collecting QC samples 

for testing field and laboratory methodologies. These QA 

methods were determined based on guidelines provided 

in Averett and Schroeder (1994) and Shampine and others (1992).

For water and sediment chemistry sampling, equipment blanks were used to document any systematic contamination from cleaning and preparation of the equipment, as well as from processing of the samples in the 

field. Similarly, a method blank run by the laboratory for 

each analytical method used documented any systematic 

contamination of the laboratory equipment.

QC samples collected along with water (environmental) samples included an equipment blank prepared at the 

beginning of each day, a trip blank, a replicate sample, 

and a matrix spike and matrix spike duplicate. Replicate 

samples were collected to ensure analytical and field 

reproducibility. The trip blank was used to document any 

volatile organic compounds that may have contaminated 

similarly prepared bottles or permeated the sample bottles along the sequence of sample shipment. The matrix 

spike and spike duplicate samples were collected as a 

second and third sample at one site and injected with a 

known solution to determine recovery to qualify the performance of the analytical equipment for these individual samples and to measure any potential interference by 

the sample water (the matrix) on the sample.

QC samples collected along with streambed sediment 

samples included a replicate sample at one station and 

two replicate samples collected at a different station: one 

used as a matrix spike and the other used as a matrix 

spike duplicate. The laboratory ran a method blank for 

each analytical method used. Chain-of-custody procedures were followed throughout the study for sample 

collection, sample shipping and receiving, analysis, and 

delivery of final data. Results of analyses of QA samples 

are in Appendixes 1-4.

Standard benthic macroinvertebrate QA/QC procedures were followed (American Society of Testing and 

Materials, 1995; American Public Health Asssociation, 

the American Water Works Association, and the Water 

Environment Federation, 1998; USEPA, 1994). All samples were labeled and preserved in 70-percent ethanol 

and returned to the laboratory at VPI for sorting and 

identification by an analyst using a dissection microscope (Zeiss, Stemi SV11) and the appropriate taxonomic keys. Sample check-in sheets and sample chainof-custody records are on file at VPI. Ten percent of the 

sorted samples were re-examined by laboratory personnel. Any additional organisms found were enumerated, 

identified, and added to the original sample vial. If the 

difference from the original sample was fewer than 10 

percent in samples with more than 100 organisms, or 

fewer than 10 organisms in smaller samples, the sample 

was accepted (Barbour and others, 1999). Raw benthic 

macroinvertebrate identification data are in Appendixes 

5 and 6.

Standard QA/QC procedures were followed with 

regard to handling sediment samples, organism cultur-
16 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

ing, and testing of the effects of sediment on laboratory 

organisms. In order to ensure organism health throughout 

the period of toxicity testing, acute and chronic reference 

tests were conducted monthly and quarterly; data were 

reported to DEQ on a quarterly basis and kept on file in 

the VPI laboratory. Chain-of-custody records, laboratory 

check-in records and test data records, including all endpoint data and water chemistry, are on file at VPI.

Water and Streambed Sediment Quality

Although sampling for this study was planned for 

periods of high and low base-flow conditions, 1998 and 

1999 were extremely dry years, with little of the higher 

seasonal precipitation expected for winter months. Sampling in both April and September 1999, accordingly, 

was conducted during low base-flow conditions. Record 

low streamflows had been recorded in most parts of Virginia throughout the winter of 1998 and into the spring 

and summer of 1999, and little significant rainfall 

occurred until September 1999 (White and others, 2000).

Water

Even under low streamflow conditions, water was 

observed to flow from the 4-in. PVC pipe at the base of 

the landfill, and in the sampled tributary and the 

unnamed stream throughout the study period. On September 5 and 6, 1999, between 3 and 4 in. of rain fell in 

the area (National Climatic Data Center, 1999). Because 

of the dry antecedent conditions, however, base-flow 

conditions were re-established by the time sampling was 

conducted on September 8.

Field Measurements

Because of the pre-existing dry conditions, all of the 

discharge measured in April in the unnamed stream and 

its tributaries can be attributed to ground-water discharge. As the result of the storm two days prior to September sampling, the discharge in September cannot 

solely be attributed to ground water; however, the discharge measured at each site in September was less than 

that measured in April (table 4). The increase in discharge from site 2 downstream to site 4 in both April and 

September shows that these are gaining streams, resulting from the discharge of ground water to the stream 

throughout the stream length.

At sites 1, 2, 3, and 4, water temperature ranged from 

12.0oC to 13.7oC in April and from 17.5oC to 19.0oC in 

September. The smallest seasonal temperature change 

was observed at site 2, nearest the landfill, with the highest temperature in April and the lowest in September. 

The water being discharged from the PVC pipe is ground 

water that has been isolated from the atmosphere, in contrast to the water at sites 1, 3, and 4. Due to the insulating 

qualities of the Earth, ground-water temperatures tend to 

remain relatively constant, unlike surface waters that are 

affected by wide-ranging air temperature (Todd, 1980).

In both April and September, specific conductance 

was lower at site 1, the reference site, than at the other 

Name

Site 1 Site 2 Site 3 Site 4

Sinking

Creek

reference

sitea

Apr Sept Apr Sept Apr Sept Apr Sept

Water temperature, in °C 12.6 19 13.7 17.5 12.4 18.4 12.0 18.6 –

Specific conductance, in μS/cm 100 118 426 912 327 501 156 232 220-230

Dissolved oxygen, in mg/L 8.8 7.8 4.4 4.1 8.7 7.9 9.6 8.4 7.2-10.0

pH, in standard units 7.6 6.7 6.6 5.9 7.3 7.1 7.5 7.3 –

Instantaneous stream discharge, in ft3/s 0.047 0.017 0.010 0.008 0.030 0.021 0.171 0.096 –

Alkalinity, in mg/L – – – – – – – – 120-130

Table 4. Field measurements of water quality and discharge of an unnamed stream and its tributary near the Blue Ridge Parkway, April and 

September, 1999, and usual ranges for selected water-quality field measurements at the Sinking Creek reference site

[°C, degrees Celsius; μS/cm, microsiemens per centimeter at 25°C; mg/L, milligrams per liter; ft3/s, cubic feet per second; –, not known]

a

Usual range during historical collection period 1990-2000
Water and Streambed Sediment Quality 17

sites. The high conductance at site 2 affected all sites 

downstream, such that conductance at both sites 3 and 4 

did not recover to the value measured at site 1. The progressively lower conductance values at sites 3 and 4 as 

compared to site 2 probably resulted from one or more 

factors: dilution by ground-water inflow along the stream 

banks; dilution of the sampled tributary by the unnamed 

stream; and (or) removal of conductive constituents that 

were in solution at site 2 by precipitation. Researchers 

from VPI periodically measured the specific conductance at site 2 from November 1998 to November 1999, 

at values ranging from 510 to 850 μS/cm. There are no 

State or Federal water-quality standards for specific conductance, and the water is not considered toxic at a measurement lower than 3,000 μS/cm. Specific conductance 

also is not considered to be a limiting factor to the biological community structure (Latimer, 1999).

The dissolved-oxygen (DO) concentration at site 2 

was much lower than that at other sites, at a concentration of 4.4 mg/L in April and 4.1 mg/L in September. At 

sites 1, 3, and 4, DO concentrations ranged from 8.7 to 

9.6 mg/L in April and from 7.8 to 8.4 mg/L in September. DO concentrations measured at site 2 in April and 

September were lower than the Virginia Surface Water 

Quality Criteria of 5.0 mg/L (daily average minimum 

concentration) and at or slightly higher than the Surface 

Water Quality Minimum of 4.0 mg/L (State Water Control Board, 1997). DO concentrations at other sites were 

higher than the standards. Similar DO concentrations 

were measured at this site by VPI between November 

1998 and November 1999; concentrations ranged from a 

low of 3.6 mg/L to 6.0 mg/L, with most values lower 

than 5.0 mg/L. Low DO conditions cannot be tolerated 

by sensitive fish and insect groups (for example, mayflies).

Although the pH also was lower at site 2 than at the 

other sites during both sampling events, the pH values 

measured in April and September were between 5.9 and 

7.6 at all stations. These values are within the acceptable 

range for surface waters, according to Virginia waterquality criteria, and are consistent with the values 

obtained from periodic sampling by VPI.

The lower DO concentration, higher specific conductance, and lower pH at site 2 relative to the other sites are 

indicative of reducing conditions normally found in landfills where anaerobic degradation is taking place. Downstream of site 2, aeration of the water as it flowed toward 

the Roanoke River resulted in progressively higher DO 

concentrations at sites 3 and 4, exceeding the concentration at the reference site, site 1. Oxygenation of the water 

downstream of site 2 also probably contributed to the 

increase in pH downstream of site 2, as metals in solution formed metal oxides and were precipitated. The 

unusual extent of precipitate along the streambed, therefore, was a result of the low pH and low DO (reducing) 

conditions in the interior of the landfill and the high concentration of constituents in solution, particularly metals, 

as would be expected in landfill leachate.

Inorganic Constituents and Total Organic Carbon

Of 55 inorganic constituents sampled for, 20 were not 

detected in either the April or September samples 

(table 5). Virginia water-quality criteria exist for 10 of 

the 35 constituents that were detected in April or September (table 6). Some constituents were detected at 

concentrations less than their respective reporting limits, 

and these concentrations are considered estimated values. Constituents that were not detected or that had estimated concentrations on both sampling dates were not 

used in the comparisons among sites; these constituents 

include total fluoride, dissolved aluminum, dissolved 

antimony, dissolved and total arsenic, total copper, dissolved lead, total mercury, dissolved and total vanadium, 

and dissolved and total zinc. If the constituent was at a 

concentration greater than its reporting limit at least 

once, it was considered in these comparisons. Constituents that were detected at equal concentrations at two 

different sites were not included in the subtotals used in 

the site comparisons that follow.

Site 1, the reference site, had the lowest concentrations for 13 of the 33 inorganic constituents detected at 

the four sites in April. Present at other sites, total nitrate 

and total aluminum were not detected at site 2; the lowest concentrations of dissolved and total iron were at site 

3; and the lowest concentrations of total organic carbon 

and dissolved and total barium were at site 4. Dissolved 

and total vanadium were not detected at any sites in 

April. In September, the lowest concentrations again 

were most often at site 1 (20 of 31 constituents detected). 

At site 2, total nitrate and total sulfate were detected at 

concentrations lower than their respective reporting limits; total aluminum and total lead were not detected. No 

constituents were at their lowest concentration at site 3; 

total iron was at its lowest concentration at site 4. Dissolved aluminum, dissolved antimony, total copper, and 

total mercury were not detected at any sites in September.
18 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

The larger number of lowest concentrations of inorganic constituents detected at site 1 confirms that it is an 

appropriate reference site. Although some constituents 

were detected at lower concentrations at other sites, these 

lower concentrations may have resulted from conditions 

at those sites that caused the removal of that constituent 

from the water. For example, in April and September, 

both total aluminum and total nitrate either were not 

detected or were at their lowest concentrations at site 2. 

In September, total sulfate also was lowest at site 2. 

These low concentrations probably resulted from reducing conditions within the landfill. The oxidized species 

nitrate and sulfate were likely not present in waters coming from the anoxic environment of the landfill because 

nitrogen within a landfill is converted to ammonia or 

nitrogen gas, and sulfur is converted to hydrogen sulfide, 

also a gas. Aluminum normally is detected in very small 

concentrations in natural water and tends to be incorporated into metal or organic complexes when the pH of the 

water is near 7 (neutral), and therefore may have been 

precipitated from the water at site 2. Aluminum concentrations increased progressively downstream of site 2 to 

values that are similar to those at the reference site. In 

April, the concentration of total organic carbon was lowest at site 4 and showed a progressive decrease from site 

2, and also may have been incorporated into organic 

complexes in the water. The low concentrations of dissolved and total barium at site 4 were comparable to 

those at site 1 in both April and September samples.

The highest concentrations for 26 of the 33 inorganic 

constituents detected in April (79 percent) were at site 2, 

closest to the landfill. The only exceptions were total lead 

(0.64 μg/L) and total copper (2.9 μg/L) at site 1, both at 

concentrations less than their respective reporting limit; 

nitrate (820 μg/L) and total mercury (0.084 μg/L, less 

than the reporting limit), which were highest at site 3; 

and total aluminum, highest at site 4 (360 μg/L). In September, highest concentrations were distributed primarily 

between sites 2 and 3. Of 31 constituents detected in September, 16 (52 percent) were at highest concentrations at 

site 2, and 13 of 31 constituents detected (42 percent) 

were highest at site 3. The only exception was total lead 

(1.1 μg/L), which was highest at site 1.

Constituent concentrations that were highest at site 2 

in both April and September included total dissolved solids, and total and dissolved forms of barium, calcium, 

cobalt, iron, magnesium, and manganese. Concentrations 

that were highest at site 2 in April and at site 3 in September included total chloride, total organic carbon, total 

sulfate, total and dissolved potassium, and total and dissolved sodium. Total nitrate was highest at site 3 in both 

April and September. In September, only total lead was 

highest at site 1; no constituent was highest at site 4.

In April, most constituent concentrations were progressively lower at sites 3 and 4 compared to those at site 

2. The exceptions were total nitrate, highest at site 3, and 

total aluminum, highest at site 4. On the other hand, several constituents were higher at site 3 than at site 2 in 

September. The different distribution may be a result of 

changed conditions near the landfill as a result of the 

storm two days prior to the September sampling.

The concentrations of total and dissolved iron and of 

manganese decreased in samples from sites downstream 

of site 2 in both April and September. Like aluminum, 

iron and manganese are readily dissolved in acidic water. 

Both constituents were at relatively high concentrations 

near site 2 and at nearly equal concentrations in water 

discharged from beneath the landfill (dissolved/total ratio 

of 103 percent for iron and 100 percent for manganese). 

By the time the water reached site 3, most of the iron and 

manganese had precipitated out, resulting in a dissolved/

Constituent

Analytical 

method

number

Reporting limit, 

in μg/L

Non-metals

Phosphate as P, ortho 300.0A 500

Metals

Antimony, total 6020 2

Beryllium, dissolved 6010B 2

Beryllium, total 6010B 2

Cadmium, dissolved 6010B 5

Cadmium, total 6010B 5

Copper, dissolved 6010B 20

Chromium, dissolved 6010B 10

Chromium, total 6010B 10

Mercury, dissolved 7470A 0.2

Molybdenum, dissolved 6010B 20

Molybdenum, total 6010B 20

Nickel, dissolved 6010B 40

Nickel, total 6010B 40

Selenium, dissolved 6010B 5

Selenium, total 6010B 5

Silver, dissolved 6010B 10

Silver, total 6010B 10

Thallium, dissolved 6010B 7.4

Thallium, total 6010B 7.4

Table 5. Inorganic constituents analyzed for but not detected in 

water samples at Blue Ridge Parkway sampling stations, April 

and September 1999

[μg/L, micrograms per liter]
Table 6. Inorganic constituents and total organic carbon detected in water samples, and associated Virginia Surface Water Quality Criteria at Blue Ridge Parkway sampling st

April and September, 1999

[Virginia Surface Water Quality Criteria are maximum contaminant levels for aquatic life and human health as defined by the State Water Control Board (1997); μg/L, microgramND, not detected; –, no criterion]

Concentration, in μg/L Virginia Surface W

i

April September Aquatic Life 

Constituent

Analytical 

method 

number

Reporting 

limit,

in μg/L

Site 1 Site 2 Site 3 Site 4 Site 1 Site 2 Site 3 Site 4 Acute Chronic

NonmetalsChloride, total 300.0A 3,000 4,600 48,200a 23,200 6,300 4,100 24,800 54,100b 12,600 860,000 230,000 

Dissolved solids, total 160.1 10,000 93,000 487,000 230,000 120,000 105,000 402,000 329,000 186,000 – – Fluoride, total 300.0A 1,000 230c 230c 240c 250c 270c 230c 310c 300c –– 

Nitrate, total 300.0A 500 700 ND 820 530 550 210c 1,700 640 – – 

Organic carbon, total 9060 1,000 1,300 5,600 2,600 960c 1,500 4,900 6,600 2,600 – – 

Sulfate, total 300.0A 5,000 2,700c 3,900c 3,100c 3,300c 3,700c 2,600c 9,800 5,400 – – 

MetalsAluminum, dissolved 6010B 100 43c 35c 41c 36c ND ND ND ND – – 

Aluminum, total 6010B 100 340 ND 110 360 440 ND 440 240 – – Antimony, dissolved 6020 2 ND 0.38c ND ND ND ND ND ND – – 

Arsenic, dissolved 6020 5 ND 1.1c 0.27c ND ND 1.2c 0.75c 0.39c – – 

Arsenic, total 6020 5 ND 1.1c 0.47c ND 0.24c 0.89c 1.1c 0.61c –– Barium, dissolved 6010B 10 42 540 77 40 48 550 120 54 – – Barium, total 6010B 10 44 540 77 42 54 560 130 58 – – Calcium, dissolved 6010B 200 7,900 69,900 27,600 13,500 9,600 65,400 39,000 19,600 – – Calcium, total 6010B 200 7,900 68,600 27,400 13,200 9,600 65,300 39,300 19,500 – – Cobalt, dissolved 6010B 10 ND 20 ND ND ND 26 ND ND – – Cobalt, total 6010B 10 ND 19 ND ND ND 25 ND ND – – Copper, total 6010B 20 2.9c ND ND ND ND ND ND ND – – 

Iron, dissolved 6010B 100 11.1c 9,100 ND 13.5 38c 11,800 47c 52c – – 

Iron, total 6010B 100 390 8,800 140 530 810 11,900 990 600 – – 
Lead, dissolved 6020 1 ND 0.079c ND ND ND 0.091c 0.094c 0.14c 120 14 

Lead, total 6021 1 0.64c 0.087c ND 0.20c 1.1 ND 0.44c 0.77c –– 

Magnesium, dissolved 6010B 200 4,200 37,000 15,200 7,100 4,700 32,100 21,400 10,000 – – Magnesium, total 6010B 200 4,100 36,100 15,100 7,000 4,700 32,100 21,600 9,900 – – Manganese, dissolved 6010B 10 1.9c 3,200 2.2c 9c 14 3,300 23 27 – – 

Manganese, total 6010B 10 9.8c 3,200 27 32 31 3,300 100 44 – – 

Mercury, total 7470A 0.2 ND ND 0.084c ND ND ND ND ND – – 

Potassium, dissolved 6010B 5,000 1,600c 5,200 4,200c 1,800c 1,900c 4,800c 7,000 2,800c –– 

Potassium, total 6010B 5,000 1,600c 5,100 4,100c 2,200c 1,600c 4,600c 7,300 2,900c –– Sodium, dissolved 6010B 5,000 6,300 35,500 17,500 7,500 6,600 23,800 33,100 10,100 – – Sodium, total 6010B 5,000 6,900 34,800 17,100 7,600 6,600 23,500 33,400 10,800 – – Vanadium, dissolved 6010B 10 ND ND ND ND ND 1.6c ND ND – – 

Vanadium, total 6010B 10 ND ND ND ND 1.7c ND 2.2c ND – – 

Zinc, dissolved 6010B 20 ND 3.0c ND ND 3.4c 5.4c 3.7c 3.7c 120 110 

Zinc, total 6010B 20 3.5c 3.8c ND ND 6.1c 6.3c 13c 3.9c –– 

Concentration, in μg/L Virginia Surface 

April September Aquatic Life 

Constituent Analytical method number Reporting limit, in μg/L Site 1 Site 2 Site 3 Site 4 Site 1 Site 2 Site 3 Site 4 Acute Chroni

aElevated reporting limit due to matrix interference bElevated reporting limit due to high analyte levels cEstimated value–value is less than reporting limit Table 6. Inorganic constituents and total organic carbon detected in water samples, and associated Virginia Surface Water Quality Criteria at Blue Ridge Parkway sampling st

April and September, 1999—Continued [Virginia Surface Water Quality Criteria are maximum contaminant levels for aquatic life and human health as defined by the State Water Control Board (1997); μg/L, microgram

ND, not detected; –, no criterion]
Water and Streambed Sediment Quality 21

total ratio of zero percent iron and 8 percent manganese 

at site 3, and 2 percent iron and 30 percent manganese at 

site 4, showing the downstream changes in solution. 

Iron, which ranged in concentration at site 2 from 8,800 

to 11,900 μg/L and manganese, at concentrations from 

3,200 to 3,300 μg/L, were the only inorganic constituents at concentrations greater than their Virginia Water 

Quality Criteria (300 μg/L and 50 μg/L, respectively) in 

April and September. Both of these standards, however, 

are standards for taste and odor in drinking water, a standard that is not currently applicable for this stream.

A comparison between site 4 and site 1, the reference 

site, indicates whether concentrations in the unnamed 

stream recovered to background conditions downstream 

of the confluence with the sampled tributary. Generally, a 

downstream decrease in constituent concentrations may 

be a result of (1) dilution of the constituents in the stream 

by inflow from tributaries, (2) dilution of constituents by 

ground-water discharge, (3) precipitation of constituents, 

(4) adsorption and concentration of constituents onto 

sediment particles, or (5) other in-stream processes.

Although concentrations of some constituents 

decreased downstream from site 2, concentrations for the 

majority of constituents at site 4 did not recover to the 

concentrations at the reference site, site 1. Concentrations for 17 of 24 constituents detected at both sites in 

April (71 percent) and 23 of 28 detected at both sites in 

September (82 percent) were greater at site 4 than at site 

1. In April, concentrations of total organic carbon, total 

nitrate, and total and dissolved barium were less at site 4 

than at site 1. In September, total aluminum, total iron, 

and total lead had concentrations lower at site 4 than 

those at site 1.

To determine whether there were seasonal or other 

time-related differences in water chemistry among the 

four sites, relative percent differences in constituent concentrations between the two sampling periods were calculated for each constituent by subtracting the 

concentration in April from the concentration in September, dividing that difference by the concentration in 

April, and multiplying the result by 100. This served to 

normalize the data around a value of zero. Constituents 

were divided into nonmetals, dissolved metals, and total 

metals, and then concentrations were plotted to determine whether there was an observable pattern in relative 

percent difference within and between groups having 

similar chemical structure and (or) reactivity (fig. 4). It is 

important to note that when values are low, as at site 1, a 

small difference in concentration can result in a large relative percent difference.

The boxplots for sites 1 and 2 show small ranges in 

percent difference in total nonmetals. Although there are 

wider ranges for dissolved metals and total metals at site 

1 relative to site 2, the medians for both sites are near 

zero, indicating that constituent concentrations in the 

stream were consistent (at these streamflows) for these 

two sample-collection dates. Larger percent differences 

in concentrations at sites 3 and 4 are seen in the wider 

ranges and the higher median values of the boxplots. The 

highest medians for each group of constituents are at site 

3, showing the greatest change in constituent concentrations from the April sample to the September sample.

Several hypotheses may explain the differences in 

concentrations between April and September samples. 

For example, prior to the April sampling, conditions 

were dry; water discharged from the PVC pipe at site 2 

and throughout the basin of the unnamed stream would 

have been representative of steady-state conditions. In 

contrast, the brief but significant storm in September two 

days prior to sampling after a prolonged dry period 

would have flushed the water in the stream as well as the 

sediment in the streambed. Although flow conditions 

were similar to conditions in April, the storm would have 

effectively redistributed any precipitate or constituents 

associated with sediment throughout the basin. These 

different sampling conditions probably affected the concentrations and the distribution of sediment and associated constituents in the basin. Another possible 

explanation for the differences in concentrations between 

the two sampling dates is seasonal changes in air and 

water temperatures, which affect conductance, pH, and 

DO concentration. These field conditions can change the 

potential for chemical precipitation and other in-stream 

processes. Also, ground water being discharged along 

the banks of streams may contain elevated concentrations of inorganic constituents as a result of contamination from the landfill and subsequent subsurface flow 

through saprolite or cracks and fissures in the rock. 

Because ground-water storage time along the crest of the 

Blue Ridge Physiographic Province can be relatively 

short (on the order of 0-2 years for springs) (Plummer 

and others, 1999), recharge from the September storm 

may have resulted in increased discharge from groundwater storage.

Organic Compounds

Of 121 organic compounds analyzed for, 104 were 

not detected in either water or bottom-sediment samples 

(table 7). Of the 17 discrete compounds that were 

detected in water in either April or September, most
22 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Figure 4. Ranges in percent difference in concentrations of inorganic constituents and organic carbon between April 1999 

sampling and September 1999 sampling, at sites near the Blue Ridge Parkway, Virginia.

(6) (7) (10) (5) (11) (10) (6) (7) (8) (6) (7) (9)

3,700

3,600

1,000

800

600

400

0

200

-100

TN DM TM TN DM TM TN DM TM TN DM TM

Site 1 Site 2 Site 3 Site 4

CONSTITUENT

DIFFERENCE IN CONCENTRATION FROM

APRIL TO SEPTEMBER, IN PERCENT

Number of observations

Outlier data value more than 3 times the 

interquartile range

Outlier data value less than or equal to 3 and 

more than 1.5 times the interquartile range

Data value less than or equal to 1.5 times

the interquartile range

(6)

75th percentile

Median

25th percentile

Total nonmetal constituent (chloride, fluoride, nitrate, 

sulfate, dissolved solids, and organic carbon)

Total/dissolved metal constituent (aluminum, arsenic,

barium, calcium, iron, lead, magnesium, manganese,

potassium, sodium, and zinc)

TN

TM/DM

EXPLANATION
Water and Streambed Sediment Quality 23

Reporting limit, in μg/kg

Constituent Water Sediment

 Method 8260B–Volatile organic compounds analyzed by GC/MS

1,1,1-Trichloroethane 1.0 5.0

1,1,2,2-Tetrachloroethane 1.0 5.0

1,1,2-Trichloroethane 1.0 5.0

1,1-Dichloroethene 1.0 5.0

2-Hexanone 5.0 20

4-Methyl-2-pentanone 5.0 20

Bromodichloromethane 1.0 5.0

Bromoform 1.0 5.0

Bromomethane 2.0 10

Carbon disulfide 1.0 5.0

Carbon tetrachloride 1.0 5.0

Chlorodibromomethane 1.0 5.0

Chloromethane 2.0 10

cis-1,3-Dichloropropene 1.0 5.0

Styrene 1.0 5.0

trans-1,3-Dichloropropene 1.0 5.0

Method 8270C–Semivolatile organic compounds analyzed by GC/MS 

1,2,4-Trichlorobenzene 10 330

1,2-Dichlorobenzene 10 330

1,3-Dichlorobenzene 10 330

2,2'-oxybis(1-Chloropropane) 10 330

2,4,5-Trichlorophenol 10 330

2,4,6-Trichlorophenol 10 330

2,4-Dichlorophenol 10 330

2,4-Dimethylphenol 10 330

2,4-Dinitrophenol 50 1,600

2,4-Dinitrotoluene 10 330

2,6-Dinitrotoluene 10 330

2-Chloronapthalene 10 330

2-Chlorophenol 10 330

2-Methylnapthalene 10 330

2-Methylphenol 10 330

2-Nitroaniline 50 1,600

2-Nitrophenol 10 330

3,3-Dichlorobenzidene 50 1,600

3-Methylphenol 10 330

3-Nitroaniline 50 1,600

Table 7. Organic compounds analyzed for but not detected in water and streambed 

sediment samples at Blue Ridge Parkway sampling stations

[μg/L, micrograms per liter, μg/kg, micrograms per kilogram, GC/MS, 

gas chromatography/mass spectrometry; PCBs, polychlorinated biphenyl

 compounds]
24 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

4,6-Dinitro-2-methylphenol 50 1,600

4-Bromophenyl phenyl ether 10 330

4-Chloro-3-methylphenol 10 330

4-Chloroaniline 10 330

4-Chlorophenyl phenyl ether 10 330

4-Methylphenol 10 330

4-Nitroaniline 50 1,600

4-Nitrophenol 50 1,600

Acenapthene 10 330

Acenapthylene 10 330

Anthracene 10 330

Benzo(a)anthracene 10 330

Benzo(a)pyrene 10 330

Benzo(b)fluoranthene 10 330

Benzo(g,h,i)perylene 10 330

Benzo(k)fluoranthene 10 330

bis(2-Chloroethoxy)methane 10 330

bis(2-Chloroethyl)ether 10 330

bis(2-Ethylhexyl)phthalate 10 330

Butylbenzyl phthalate 10 330

Chrysene 10 330

Dibenzo(a,h)anthracene 10 330

Dibenzofuran 10 330

Dibutylphthalate 10 330

Diethyl phthalate 10 330

Dimethyl phthalate 10 330

Di-n-octyl phthalate 10 330

Fluoranthene 10 330

Fluorene 10 330

Hexachlorobenzene 10 330

Hexachlorobutadiene 10 330

Hexachlorocyclopentadiene 50 1,600

Hexachloroethane 10 330

Indeno (1,2,3-c,d) pyrene 10 330

Isophorone 10 330

Napthalene 10 330

Nitrobenzene 10 330

N-Nitroso di-n-propylamine 10 330

Reporting limit, in μg/kg

Constituent Water Sediment

Table 7. Organic compounds analyzed for but not detected in water and streambed 

sediment samples at Blue Ridge Parkway sampling stations—Continued

[μg/L, micrograms per liter, μg/kg, micrograms per kilogram, GC/MS, 

gas chromatography/mass spectrometry; PCBs, polychlorinated biphenyl

 compounds]
Water and Streambed Sediment Quality 25

N-Nitrosodimethylamine 10 330

Pentachlorophenol 50 1,600

Phenanthrene 10 330

Phenol 10 330

Pyrene 10 330

Method 8081–Semivolatile organic compounds analyzed by GC (PCBs)

Arochlor 1016 1.0 33

Arochlor 1221 1.0 33

Arochlor 1232 1.0 33

Arochlor 1242 1.0 33

Arochlor 1248 1.0 33

Arochlor 1254 1.0 33

Arochlor 1260 1.0 33

 Method 8081A–Semivolatile organic compounds analyzed by GC 

(Organochlorine pesticides)

4,4'-DDE 0.05 1.7

a-BHC 0.05 1.7

a-Chlordane 0.05 1.7

Aldrin 0.05 1.7

Chlorobenzilate 0.05 1.7

d-BHC 0.05 1.7

Dieldrin 0.1 1.7

Endosulfan I 0.05 1.7

Endosulfan II 0.05 1.7

Endosulfan sulfate 0.05 1.7

Endrin 0.05 1.7

Endrin ketone 0.05 1.7

g-BHC A37(Lindane) 0.05 1.7

g-Chlordane 0.05 1.7

Heptachlor 0.05 1.7

Heptachlor epoxide 0.05 1.7

Methoxychlor 0.5 3.3

Toxaphene 5 67

Reporting limit, in μg/kg

Constituent Water Sediment

Table 7. Organic compounds analyzed for but not detected in water and streambed 

sediment samples at Blue Ridge Parkway sampling stations—Continued

[μg/L, micrograms per liter, μg/kg, micrograms per kilogram, GC/MS, 

gas chromatography/mass spectrometry; PCBs, polychlorinated biphenyl

 compounds]
26 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

organic compounds were detected only at site 2 (table 8). 

The only exceptions are methylene chloride, a common 

laboratory solvent, which was detected at least once at 

each of the four sites, and 2-butanone, or methyl ethyl 

ketone, which was detected at site 2 and at a concentration less than its reporting limit at site 3 in September. 

Although organic compounds detected in water at site 2 

included both volatile and semivolatile organic compounds, no organochlorine pesticides or PCBs were 

detected in any water samples. Volatile or semivolatile 

compounds are quickly converted to a gaseous state (volatilized) when exposed to the atmosphere. This volatility 

probably explains their presence in water sampled from 

site 2, closest to the landfill, and their absence from samples collected at sites 3 and 4. Constituents that were not 

detected or had estimated concentrations on either sampling date were not used in the comparisons among sites. 

A compound is included in the following discussion if it 

was detected at a concentration greater than its reporting 

limit in at least one sample.

Constituents detected were primarily industrial and 

(or) manufacturing solvents (table 9), some of which 

tend to persist in the environment and have a high potential for bioconcentration (the accumulation of persistent 

contaminants in plants and animals). Although several of 

these compounds detected have water-quality criteria 

related to human health, no compounds detected in either 

April or September were present at concentrations 

greater than the Virginia Water Quality Criteria (State 

Water Control Board, 1997) (table 6). Several of the 

organic compounds found in April or September also 

were detected in ground-water samples collected and 

reported to DEQ during periodic monitoring from 1996-

2000. These include benzene, chloroethane, dichlorobenzene, 1,1-dichloroethane, cis-1,2-dichloroethene, methylene chloride, tetrachloroethene, trichloroethene, vinyl 

chloride and o-xylene (Virginia Department of Environmental Quality, unpub. data, 2000).

Quality Control Samples

The results of analyses of QC samples associated 

with water samples collected are in Appendixes 1 and 2. 

Duplicate analyses showed good reproducibility for all 

constituents analyzed in both April and September.

In April, total and dissolved aluminum, dissolved 

antimony, total iron, total magnesium, and total and dissolved sodium were detected in laboratory method 

blanks. Dissolved aluminum, magnesium, and sodium in 

the equipment blank that was collected prior to the environmental samples reflect detections in the laboratory 

method blank. This indicates that any contamination 

from these constituents probably was due to laboratory 

practices. Concentrations of all constituents in blanks 

were less than their reporting limits, however, so that no 

qualification of the environmental data is needed for 

April.

In September, total dissolved solids, total organic carbon, total chloride, dissolved iron, dissolved sodium, and 

total zinc were detected in laboratory method blanks, all 

at concentrations lower than their reporting limits. The 

equipment blank reflects the detection of dissolved iron, 

sodium, and zinc in the laboratory method blank. All 

constituents in blanks are at concentrations less than the 

reporting limit, so that no qualification of the environmental data is needed for September.

A duplicate sample collected for organic constituents 

at site 2 in April showed very good reproducibility. No 

organic compounds analyzed for were detected in equipment blanks that were collected prior to collection of 

environmental samples in either April or September. The 

trip blank in September showed the detection of methylene chloride, a solvent commonly used in laboratory 

analysis of organic compounds and often found in low 

concentrations as a laboratory contaminant. Based on 

these QA results, no qualification of the results of 

organic compounds is necessary for either April or September samples. 

Streambed Sediment

Sediment moves along a streambed at a relatively 

slow rate, making it useful in evaluating any long-term 

effects of the water quality of the stream. Hydrophobic 

organic compounds and metal ions tend to bind or adhere 

to sediment particles; therefore, chemical analysis of any 

material on the surface of streambed sediment that has 

been exposed to consistent concentrations of constituents 

in stream water over a period of time may display a 

"record" of the constituents.

The movement rate of sediment is largely determined 

by grain size, because water moves lighter particles such 

as clays and silts faster than heavier particles. As water 

slows and flow rates drop (for example, after a storm), 

particles will tend to be sorted by size, with the heavier 

(larger) grains on the bottom and finer (smaller) grains 

on top. Finer particles also are deposited along stream 

margins, where flow rate may be reduced by friction or 

reduction in water depth.

A mass of fine-grained sediments has a larger surface 

area than an equal mass of larger particles such as sand, 

rocks, or boulders. Therefore, organic or inorganic com-
Constituent Reporting limit, in μg/L

Concentration, in μg/L Virginia Surface W

in 

April September Aquatic Life 

Site 1 Site 2 Site 3 Site 4 Site 1 Site 2 Site 3 Site 4 Acute Chronic

Method 8260B–Volatile organic compounds analyzed by GC/MS1,1-Dichloroethane 2.0 ND 28 ND ND ND 27 ND ND – – 1,2-Dichloroethane 2.0 ND 2.3 ND ND ND 2.6 ND ND – – cis-1,2-Dichloroethene 2.0 ND 57 ND ND ND 71 ND ND – – trans-1,2-Dichloroethene 1.0 ND 1.3 ND ND ND 1.2 ND ND – – 1,2-Dichloroethene (total) 2.0 ND 59 ND ND ND 73a ND ND – – 

1,2-Dichloropropane 2.0 ND 2.5 ND ND ND 2.7 ND ND – – Benzene 2.0 ND 9.5 ND ND ND 10 ND ND – – 2-Butanone (methyl ethyl ketone) 5.0 ND ND ND ND ND ND 2.4b ND – – 

2-Butanone (methyl ethyl ketone) 10.0 ND ND ND ND ND 44 ND ND – – Chlorobenzene 2.0 ND 0.74b ND ND ND 0.87b ND ND – – 

Chloroethane 4.0 ND 5.4 ND ND ND 3.5b ND ND – – Ethylbenzene 2.0 ND 8.3 ND ND ND 13 ND ND – – Methylene chloride 2.0 ND 4.5 0.24b ND 0.23b,c 5.1c ND 0.21b,c –– 

Tetrachloroethene 2.0 ND 8.1 ND ND ND 5.9 ND ND – – Toluene 2.0 ND 18 ND ND ND 30 ND ND – – Trichloroethene 2.0 ND 16 ND ND ND 12 ND ND – – Vinyl chloride 4.0 ND 6.7 ND ND ND 7.1 ND ND – – Xylenes (total) 2.0 ND 55 ND ND ND 74 ND ND – – Method 8270C–Semivolatile organic compounds analyzed by GC/MS1,4-Dichlorobenzene 10.0 ND 10 ND ND ND 11 ND ND – – 

Table 8. Organic compounds detected in water samples, and associated Virginia Surface Water Quality Criteria at Blue Ridge Parkway sampling stations, April and Se[μg/L, micrograms per liter; GC/MS, gas chromatography/mass spectrometry; ND, not detected; –, no criterion]

a Elevated reporting limit due to high analyte levelsb Estimated value–value is less than reporting limitc Associated method blank contains the target analyte at a reportable level
28 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Analyte Use Environmental fate

Potential for 

bioconcentration

in aquatic

organisms

Method 8260B–Volatile organics compounds analyzed by GC/MS

1,1-Dichloroethane

Solvent for plastics, oils, and fats; cleaning agent; degreaser; fumigant and insecticide spray; formerly used as an 

anesthetic.

Volatilizes rapidly if released on land, although it 

may leach into ground water, where fate is 

unknown. Half-life of 62 days in the atmosphere, 

2 to 9 days from surface water.

Low

1,2-Dichloroethane

Manufacturing, fumigant, solvent for fats, 

oils, waxes, gum resins, and particularly 

rubber, cleaning agent.

Evaporates rapidly. Half-life in atmosphere 

approximately 1 month, up to 10 days from 

water.

Low

cis-1,2-Dichloroethene

Solvent for perfumes, dyes, and lacquers, 

thermolastics, fats, and phenols. Agent in 

retarding fermentation. Very flammable.

Under anaerobic conditions, may likely be found 

as breakdown products of reductive dehalogenation of trichloroethylene and tetrachloroethylene. 

Will evaporate on soil, or leach into ground water 

where slow biodegradation will occur. In water, 

will volatilize (half-life 3 hours).

Data not available

trans-1,2-Dichloroethene

Solvent for waxes and resins, extraction 

of rubber, as refrigerant, in manufacturing, extraction of oils from fish and 

meat.Very flammable.

Priority pollutant. In anaerobic conditions that 

may exist in landfills or sediments, can be 

formed as a breakdown product from reductive 

halogenation of trichloroelthylene, tetrachloroethylene, and 1,1,2,2,-tetrachloroethane. Evaporates on soil or leaches into ground water, where 

slow bidegradation should occur. Half-life in 

water, 3 hours. Half-life in atmosphere 3.6 days.

Data not available

1,2-Dichloropropane

Insecticide mixture for stored grain for 

livestock, solvent in plastics, resins, and 

metals industries, rubber processing, 

degreasing, oil and fat solvent, fumigant, 

insecticide for nematodes, dry cleaning 

fluids.

Evaporates on soil. Detected in ground water 

where fate is unknown. Half-life in water 6 hours 

to 10 days. Half-life in atmosphere greater than 

23 days.

Low

Benzene

Manufacturing for medicinal chemicals, 

dyes, organic compounds, artifical 

leather, linoleum, varnishes, lacquer, 

printing, paints, degreaser.

In soil, will rapidly evaporate, and that which 

does not will be highly mobile in soil, and may 

leach to ground water. Subject to biodegradation 

on shallow, anaerobic ground waters, but probably not under anaerobic conditions. Half-life in 

water, 3 hours. Half-life in atmosphere 17 days.

Low

2-Butanone 

(methyl ethyl ketone)

Solvent, surface coating industry, lacquer 

and varnish industry, pharmaceuticals and 

cosmetics, synthetic rubber manufacturing, cements and adhesives.

On ground, partially evaporates, partly leaches 

into ground. Degradation in soil is unknown. In 

water, volatilizes (half-life 3-12 days) or is 

slowly biodegraded. In atmosphere, half-life 2.3 

days or less.

Low

Chloroethane

Chemical intermediate, refrigerant, solvent, alkylating agent, manufacturing, 

solvent, insecticides.

Evaporates rapidly in soils where release is possible, but hydrolyzes rapidly in water, and is susceptible to leaching. Half-life in atmosphere ~40 

days. Half-life in water 1-6 days. In moist soil 

systems or in ground water, hydrolysis may be 

the most important mechanism, estimated to be 

38 days at 25°C.

Low

Ethylbenzene Intermediate for styrene monomer production, solvent.

Volatilizes. Moderate adsorption in soil, may biodegrade. Half-life in atmosphere is 0.5 to 2 days. 

Half-life in water several days to 2 weeks. 

Data not available

Methylene chloride

Paint strippers, aerosols, chemical processing, foam blowing agent, metal 

degreasing, electronics.

Volatilizes. Probably will leach through subsoil 

into ground water. Degradation in ground water 

is unknown. In water, volatilizes (half-life is 

hours). Biodegradation will be slow compared to 

evaporation. In soil, may biodegrade. Half-life in 

atmosphere is several months.

Low

Table 9. Organic compounds detected in water or streambed sediment at Blue Ridge Parkway sampling stations, April and September, 1999,

their use, environmental fate, and potential for bioconcentration (Spectrum Laboratories, Inc., 2001; U.S. Environmental Protection 

Agency, 1998)
Water and Streambed Sediment Quality 29

Tetrachloroethene

Solvent in drycleaning, degreasing solvent, chemical intermediate for fluorocarbons, agent in textile manufacture.

If released to soil, subject to evaporation into the 

atmosphere and to leaching into the ground 

water. Biodegradation may be important in 

anaerobic soils. In water, subject to rapid volatilization (half-life 3 hours to 14 days). In atmosphere, half-life of up to 2 months. 

Low

Toluene

Chemical intermediate for benzene and 

other chemicals, solvent, gasoline blending.

At soil surface, lost by evaporation, although it is 

relatively mobile in soil and may reach ground 

water and remain there. In water, lost by volatilization and biodegradation (half-life days to several weeks) In atmosphere, half-life is 3 hours to 

less than 2 days.

Low

Trichloroethene

Degreasing of metals, chemical intermediate, solvent, refrigerant and heat 

exchange liquid.

May be transported through soil; low potential to 

adsorb to sediments. Rapid evaporation from 

water (half-life several minutes to hours)

Moderate

Vinyl chloride In plastic industry to produce PVC, as 

refrigerant, chemical intermediate.

In soil, subject to rapid volatilization. Any which 

does not evaporate will be expected to be highly 

mobile in soil and may leach to the groundwater. 

Subject to degradation under anaerobic conditions, but some data suggest that it is resistant to 

biodegradation in aerobic systems. Half-life in 

water less than 1 hour, half-life in atmosphere of 

1.5 days.

Data not available

Xylenes (total)

Used in gasoline, solvents, chemical 

intermediates, manufacturing, pharmaceutical synthesis, insecticides.

In soil, volatilizes and leaches into ground. In 

water, volatilization, half-life 1-6 days. Can persist in ground water. In atmosphere, half-life of 

1.7 to 18 hours. Some adsorption to sediment.

Data not available

Method 8270C–Semivolatile organic compounds analyzed by GC/MS

1,4-Dichlorobenzene Insecticidal fumigant, dye intermediate 

and insecticide manufacture.

In soil, moderately to tightly adsorbed. Leaching 

to ground water can occur. Volatilization or slow 

biodegradation may occur. Volatile from water 

with half-life of 4.3 hours. Half-life in atmosphere is estimated at 31 days. Adsorption to sediments is a major environmental fate process. Not 

expected to biodegrade under anaerobic conditions.

Data not available

Method 8081A–Semivolatile organic compounds analyzed by GC

4,4'DDT Pesticide

Banned from general use in the United States 

since 1972. Very persistent in the environment. 

Significant evidence that it significantly bioconcentrates in fish, and adsorbs strongly to sediment.High

Analyte Use Environmental fate

Potential for 

bioconcentration

in aquatic

organisms

Table 9. Organic compounds detected in water or streambed sediment at Blue Ridge Parkway sampling stations, April and September, 1999,

their use, environmental fate, and potential for bioconcentration (Spectrum Laboratories, Inc., 2001; U.S. Environmental Protection 

Agency, 1998)—Continued
30 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

pounds that adhere to the surface of sediment particles 

tend to be concentrated in areas where fine-grained materials are located. This sorting and concentrating also 

result in a streambed sediment chemistry that may be 

more highly variable than the water chemistry of the 

stream.

Inorganic Constituents and Total Organic Carbon

Of 25 constituents in streambed sediment samples 

analyzed for in April and September, including total metals and total organic carbon (excluding percent moisture, 

a physical measurement), 22 were detected in April, and 

20 were detected in September, for a total of 24 constituents detected (table 10). Sodium was the only constituent 

analyzed for and not detected at any site. In April, the 

highest concentrations of 13 of 22 constituents detected 

(59 percent) were at site 4, including copper, lead, and 

zinc. Concentrations of 6 of 22 constituents (27 percent) 

were highest and concentrations of 13 constituents (59 

percent) were lowest at site 2. Excluding arsenic, selenium, and silver, for which concentrations at all sites 

were less than the reporting limit, concentrations for 18 

out of 19 constituents detected (95 percent) were greater 

at one of the sites influenced by the landfill (sites 2, 3, or 

4) than at site 1. The exception was nickel, which was 

highest at site 1 (5.6 mg/kg).

In September, the lowest concentrations for 12 of the 

20 constituents detected (60 percent) were in samples 

from site 1. The highest concentrations for 12 of the 20 

constituents detected (60 percent), including cadmium, 

copper, mercury, and zinc, were at site 2. The highest 

concentrations for 6 of 20 constituents (30 percent) were 

detected in samples from site 3, while the highest concentration of lead (10 mg/L) was at site 4. Concentrations 

for all 20 constituents detected were higher at either site 

2, 3, or 4 than at site 1. (Because some constituents were 

at equal concentrations at two sites, percentages do not 

sum to 100.)

Overall, these data show a change in the distribution 

of constituents associated with sediment between April 

and September. In April, most of the lowest concentrations were at site 2 and most of the highest concentrations at site 4, with a few high concentrations at site 3. In 

September, most of the lowest concentrations were at the 

reference site (site 1) and the highest concentrations were 

at site 2, with a few high concentrations at sites 3 and 4. 

In April, concentrations of several constituents increased 

from site 2 downstream to site 4, while in September, the 

opposite occurred: several constituents decreased from 

their highest concentrations at site 2 to site 4.

As with water samples, the relative percent differences in constituent concentrations between April and 

September streambed sediment samples were calculated 

by subtracting the concentration in April from that of 

September, then dividing by the concentration in April. 

The result was then multiplied by 100 to represent the 

relative change between the two sampling dates as a percentage (fig. 5). This approach serves to normalize the 

data around a value of zero. The greatest relative difference, indicating the greatest change from April to September, is seen at site 2. Medians are very close to zero at 

the other three sites, indicating little change in sediment 

concentration of metal constituents between April and 

September.

There are several possible reasons for the change in 

constituent concentrations in sediment at site 2. These 

include seasonality, including changes in temperature 

and DO concentration, as well as other factors that are 

not discernible from two sampling events. For example, 

in April, the lack of recent significant rainfall allowed the 

streams to reach a steady-state flow condition. Streamwater chemistry downstream of the PVC pipe probably 

was much like ground-water chemistry within the landfill, including a lower pH than at site 1 and very low DO 

concentrations. It is likely that conditions within the 

landfill were such that dissolved metal and nonmetal 

constituents remained in solution until they were discharged, and yellowboy was formed as a precipitate as 

the constituents became oxidized downstream. Because 

constituents remained either in solution or in the precipitate, concentrations in the streambed sediments were low 

at site 2 relative to concentrations at the other sites. Precipitation of the metals on sediment occurred downstream, as the DO concentration increased.

In September, the storm two days prior to sample collection disrupted the pre-existing steady-state conditions, 

but base-flow conditions and low DO concentrations 

were quickly re-established. However, the inflow of fresh 

water at the site changed water and sediment conditions 

so that they were no longer in a steady state. Most of the 

top layer of sediment and associated precipitate was 

washed away. The streambed sediment that was collected 

for sampling, although still very fine silt and (or) precipitate, was from deeper in the streambed.

Organic Compounds

Organic compounds detected in April and September 

in streambed sediment included both volatile organic and 

semivolatile organic compounds and one organochlorine 

pesticide (table 11). Six compounds within these groups 
Water and Streambed Sediment Quality 31

Constituent Method Units Reporting 

limit

Concentration, in units noted

April September

Site 1 Site 2 Site 3 Site 4 Site 1 Site 2 Site 3 Site 4

Aluminum 6010B mg/kg 10 7,650 3,350 8,100 14,400 5,690a 10,600a 8,280a 7,260a

Antimonyb 6020 μg/kg 200 ND ND ND 60.3c ND ND ND ND

Arsenic 6020 μg/kg 500 481c 1,060 319c 390c 680 1,100 510 540

Barium 6010B mg/kg 1.0 62.3 77.2 74.2 83.6 61.3a 120a 94.5a 57.3a

Beryllium 6010B mg/kg 0.2 0.71 0.63 1.0 1.1 0.79 1.5 1.3 1.0

Cadmium 6010B mg/kg 0.5 ND ND ND ND 0.24c 0.7 0.34c 0.33c

Calcium 6010B mg/kg 20 675 1,120 1,130 1,160 657a 2,690a 1,850a 894a

Chromium 6010B mg/kg 1.0 11.8 1.8 10.4 14.4 8.7a 9.8a 10.3a 10.3a

Cobalt 6010B mg/kg 1.0 5.4 2.7 8.2 8.0 4.1a 5.6a 11.2a 6.6a

Copper 6010B mg/kg 2.0 3.5 1.9c 4.2 7.0 3.7 5.6 5.5 5.5

Iron 6010B mg/kg 10 15,900 34,700 17,900 23,400 14,100 42,200 21,000 18,800

Lead 6020 μg/kg 100 8,250 2,340 5,270 15,600 9.4 7.9 7.8 10

Magnesium 6010B mg/kg 20 798 568 1,130 1,410 796a 1,970a 1,690a 1,410a

Manganese 6010B mg/kg 1.0 278 73.6 760 383 230a 198a 1,090a 270a

Mercury 7471A mg/kg 0.033 ND ND ND ND 0.0056c 0.013c 0.0075c ND

Molybdenum 6010B mg/kg 2.0 ND 1.2c ND ND ND ND ND ND

Nickel 6010B mg/kg 4.0 5.6 2.1c 4.6 4.5 2.4c 3.1c 4.7 3.2c

Potassium 6010B mg/kg 500 430c 223c 500 878 457c 845 849 820

Selenium 6020 μg/kg 500 78.8c 114c 93.4c 76.8c 0.099c 0.15c 0.16c 0.074c

Silver 6010B mg/kg 1.0 0.33c 0.46c 0.29c 0.37c ND ND ND ND

Sodium 6010B mg/kg 500 ND ND ND ND ND ND ND ND

Thalliumb 6020 μg/kg 100 86.6c 39.5c 117 204 ND ND ND ND

Total organic carbon 9060 mg/kg 2,000 9,820 36,800 3,970 1,380c 7,300 14,600 22,100 5,660

Vanadium 6010B mg/kg 1.0 17.8 8.3 23.1 29 15.9a 24.9a 22.6a 20.0a

Zinc 6010B mg/kg 2.0 59.7 33.9 37.6 63.6 52a 66.2a 41.1a 45.5a

Percent moisture ASTM % 0.2 38.6 88.6 28.3 41.3 40.1 61.6 51.3 31.8

Table 10. Inorganic constituents, total organic carbon, and percent moisture in streambed sediment samples at Blue Ridge Parkway sampling 

stations, April and September, 1999

[mg/kg, milligrams per kilogram; μg/kg, micrograms per kilogram; ND, not detected; ASTM, American Society of Testing and Materials; 

%, percent]

a Serial dilution of a digestate in the analytical batch indicates that physical and chemical interferences are present 

b Analysis in September using method 6010B with reporting limit of 1,000 μg/kg resulted in no detections of this constituent

c

Estimated result–result is less than reporting limit
32 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Figure 5. Ranges in percent difference in concentrations of inorganic constituents associated with streambed sediment 

between April 1999 sampling and September 1999 sampling, at sites near the Blue Ridge Parkway, Virginia.

500

-100

0

100

200

300

400

-200

DIFFERENCE IN CONCENTRATION FROM 

APRIL TO SEPTEMBER, IN PERCENT

M1 M2 M3 M4

(14) (14) (14) (14)

CONSTITUENT

Number of observations

Outlier data value more than 1.5 times 

the interquartile range 

Data value less than or equal to 1.5 times

the interquartile range 

(14)

75th percentile

Median

25th percentile

Metal constituent and site number (aluminum, arsenic,

barium, calcium, iron, lead, magnesium, manganese, 

potassium, sodium, zinc)

M3

EXPLANATION
Water and Streambed Sediment Quality 33

Compound Reporting 

limit

Concentration, in μg/kg

April September

Site 1 Site 2 Site 3 Site 4 SIte 1 Site 2 Site 3 Site 4

Method 8260B–Volatile organic compounds analyzed by GC/MS

1, 1-Dichloroethane 5.0 ND 15 ND ND ND 2.8a ND ND

1, 2-Dichloroethene (total) 5.0 ND 13 ND ND ND 1.4a ND ND

Acetone 20 4.8a 9.2a ND ND ND ND ND ND

Benzene 5.0 ND 2.4a ND ND ND ND ND ND

Chloroethane 10 ND 2.1a ND ND ND ND ND ND

cis-1,2-Dichloroethene 2.5 ND 13 ND ND ND 1.4a ND ND

Cyclotetrasiloxane, octamethl- – ND ND ND ND 8c,e ND ND ND

Methylene chloride 5.0 0.93a,d 3.5a,d 1.0a,d 0.98a,d 0.94a,d 0.58a,d 1a,d 0.73a,d

Tetrachloroethene 5.0 ND 18 ND ND ND ND ND ND

Trichloroethene 5.0 ND 8.0 ND ND ND 0.82a ND ND

Vinyl chloride 10 ND 1.3a ND ND ND ND ND ND

Method 8270C–Semivolatile organic compounds analyzed by GC/MSe

Gamma-sitosterol – ND ND ND ND ND ND 3,600a,c ND

1-Heptadecene – ND ND ND ND ND 950a,c ND ND

Cholesterol – ND ND ND ND ND 2,100a,c ND ND

Docosane – ND ND ND ND ND 900a,c ND ND

Stigmast-4-en-3-one – ND ND ND ND ND 1,900a,c ND ND

Method 8081A–Semivolatile organic compounds analyzed by GC (Organochlorine Pesticides)

4, 4'-DDT 1.7 ND ND ND 7.5 ND 4.2 ND ND

4, 4'-DDT (duplicated by laboratory) 1.7 ND ND ND 7.8 ND 5.3 ND ND

4, 4’-DDD 1.7 ND ND ND ND ND 0.94a ND ND

4, 4’-DDD (duplicated by laboratory) 1.7 ND ND ND ND ND 1.1a ND ND

Table 11. Organic compounds detected in streambed sediment samples at Blue Ridge Parkway sampling stations, April and September, 1999

[μg/kg, micrograms per kilogram; GS/MS, gas chromatography/mass spectrometry; GC, gas chromatography; ND, not detected; –, not determined]

a Estimated result–result is less than reporting limit

b

 Confident identification–major ions and ratios largely agree

c Result measured against nearest internal standard assuming a response factor of 1

d

 Associated method blank contains the target analyte at a reportable limit

e

 Tentatively identified
34 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

were termed "tentatively identified" by the laboratory. 

Only those constituents that were confidently identified 

and were present at concentrations greater than their 

reporting limits are discussed below. Unknown compounds were detected at all sites, including the reference 

site, and were not included in this report. There are no 

aquatic life or human health criteria for organic constituents associated with sediment in Virginia.

In April, the pesticide 4,4'-DDT was detected at a 

concentration greater than its reporting limit at site 4, and 

1,1-dichloroethane, and 1,2-dichloroethene were greater 

than their reporting limits at site 2. DDT is a compound 

with very low solubility that strongly adheres to sediment 

particles; little degradation is expected. Its use in the 

United States has been banned since the 1970s. The compounds 1,1-dichloroethane and 1,2-dichloroethene also 

were detected in water samples collected at site 2 in both 

April and September. Under anaerobic conditions as in a 

landfill, 1,1-dichloroethane and 1,2-dichloroethene are 

degradation products of trichloroethene and tetrachloroethene, both of which also were detected in water samples in both April and September at site 2.

In September, the only organic constituent detected at 

a concentration greater than its reporting limit was 4,4'-

DDT, at site 2. Similar to the majority of metal and nonmetal constituents associated with streambed sediment, 

4,4'-DDT was found at the farthest downstream site 

(site 4) in April and near the landfill (site 2) in September.

Quality Control Samples

The results of analyses of QC samples associated 

with streambed sediment for each sampling date are in 

Appendixes 3 and 4. For metals and nonmetals, the laboratory method blanks show the detection of cadmium and 

cobalt in April and of beryllium, iron, and manganese in 

September. The concentration of each of these constituents is less than the reporting limit for each constituent, 

so that no qualification of environmental data is necessary. In the results for the September data, analysts noted 

that physical and chemical interference was present. The 

constituents that may have been affected by this interference are noted in table 11. Duplicate sediment samples 

collected at site 2 were comparable to the results for the 

original samples.

For organic constituents, the laboratory method blank 

for sediment in April showed detection of four compounds, two of which were unknowns and are not 

included in this report. A compound that results from an 

aldol reaction, generally described as "aldol condensation product," was detected in the laboratory method 

blank, but in no environmental samples. Methylene chloride, on the other hand, was detected in all samples, probably as a contaminant from its use as a solvent in the 

analysis. In September, methylene chloride again was 

detected in the blank as well as in all samples. Other 

compounds detected in September were chloroform, 

which was detected in no other sample, and four 

unknown compounds. All compounds detected in QC 

samples were at concentrations less than their reporting 

limits. No qualification of the results of organic compounds in sediment is necessary. A duplicate sample was 

collected at site 2, and results were comparable to the 

original sample.

Ecotoxicology

Ecological sampling and toxicity testing were done to 

assess stream conditions at the five sampled sites with 

regard to the benthic macroinvertebrate community. 

These assessments included the number of organisms 

and the state of the benthic macroinvertebrate community, stream habitat conditions, and toxicity of the organisms to the water and sediment collected near the landfill.

Benthic Macroinvertebrates

From samples collected in April, six of nine benthic 

macroinvertebrate community metrics were determined 

to be significantly different from normal (Shapiro-Wilk 

Test, α=0.05) (table 12). Data transformation increased 

the number of metrics that were distributed normally 

from three to four. An analysis of variance (ANOVA) 

(α=0.05) was conducted on the normal data, and nonparametric statistics were used to analyze data that did 

not meet the assumption of normality (nonparametric 

one-way, or NPAR1Way ANOVA, α=0.05). An 

NPAR1Way analysis was conducted on both the transformed and untransformed data that failed the assumption of normality (table 12). A General Linear Model 

(GLM, α=0.05) on ranked data was used to determine 

whether there were significant relations among all sites 

(Least Squares Difference, or LSD, α=0.05) (table 13).

The ANOVA conducted on the four metrics where 

data were normally distributed determined that there 

were significant differences among sites for stonefly 

abundance, mayfly abundance, percent mayfly abundance and EPT abundance (table 12). Nonparametric statistics on non-normal data determined that the five 

remaining metrics also were significantly different from 
Ecotoxicology 35

Benthic macroinvertebrate metric

Normality

(Shapiro-Wilk 

Test, α=0.05)

Normality after 

transformation

(α=0.05)

ANOVA

(α=0.05)

NPAR1Way 

ANOVAa

(α=0.05)

NPAR1Way 

ANOVAb

(α=0.05)

Abundance 0.0075 0.0013c n.a. 0.0051 <0.0001

Taxa richness 0.0072 0.0017c n.a. 0.0051 <0.0001

Caddisfly abundance 0.0101 0.0485c n.a. 0.0055 <0.0001

Stonefly abundance 0.0024 0.0989c <0.0001 n.a. 0.0030

Mayfly abundance 0.2092 Not needed <0.0001 n.a. n.a.

Percent mayfly abundance 0.3507 Not needed <0.0007 n.a. n.a.

EPT abundance 0.1015 Not needed <0.0001 n.a. n.a.

Percent EPT abundance 0.0069 0.0023d n.a. 0.0034 0.0001

EPT richness 0.0098 0.0001c n.a. 0.0171 0.0001

Table 12. Statistical analysis of benthic macroinvertebrate metrics for samples collected at Blue Ridge Parkway sampling 

sites in April 1999

[ANOVA, analysis of variance; NPAR1Way ANOVA, nonparametric one-way analysis of variance; EPT, 

Ephemeroptera/Plecoptera/Trichoptera; α, probability of incorrectly rejecting the null hypothesis; <, actual 

value is known to be less than value shown; n.a., not applicable]

a

 Statistics conducted on transformed data

b Statistics conducted on untransformed data

c Square root transformation

d Percent arcsine (Asin) square root transformation

Benthic macroinvertebrate

metric

Ranking of Sites

High Low

Abundance 1 3-BC 4 3 2

Taxa richness 1 3-BC 3 4 2

Caddisfly abundance 1 3-BC 3 4 2

Stonefly abundance 3-BC 3 1 4 2

Mayfly abundance 1 3-BC 4 3 2

Percent mayfly abundance 1 3-BC 3 4 2

EPT abundance 1 3-BC 3 4 2

Percent EPT abundance 3-BC 1 3 4 2

EPT richness 3-BC 1 4

2 4 3

Table 13. Ranking and statistical analysis of sites for nine benthic macroinvertebrate 

metrics at Blue Ridge Parkway sampling sites in April 1999.

[Sites are ranked from high to low for each metric with high values generally associated with 

good water-quality conditions. Each outlined dark gray block contains a group of sites that do 

not differ significantly from each other. Light gray blocks contain an individual site that is 

significantly different from other sites.]
36 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

each other. Using both parametric and nonparametric statistics, significant differences among sites were determined for all nine benthic macroinvertebrate metrics 

assessed in April.

Site 1 was ranked highest (least degraded) for six of 

the nine metrics; site 3-BC was ranked highest three 

times (table 13). Site 2 was ranked lowest for all nine 

benthic macroinvertebrate metrics, and was significantly 

lower than the other sites for eight of the nine metrics. 

No environmentally sensitive orders of EPT were collected at site 2, nearest the landfill, and the only species 

found in all four replicates was the dipteran Ptychoptera

(Ptychopteridae), an organism that is highly tolerant to 

environmental stress (app. 5). Other tolerant organisms at 

site 2 included snails (Physidae), worms (Oligochaeta), 

and other chironomids.

The mean abundance and taxa richness metrics were 

much lower at site 2 relative to all sites sampled in April 

1999 (table 14). For example, mean abundance and taxa 

richness were 12.5 and 3.0 at site 2 compared to 120 and 

18.8 at site 1. Caddisflies, stoneflies, and mayflies were 

not found at site 2; numbers of caddisflies and mayflies 

were highest at site 1 relative to sites 3, 3-BC, and 4. 

Mean stonefly abundance (34.5 organisms) was highest 

at site 3-BC (table 14). Sites 1, 2, 3, and 4 had significantly lower numbers of stoneflies relative to site 3-BC. 

Site 1 had the highest number of mayflies (65) and percent mayflies, representing 54 percent of the sample. 

Sites 3, 3-BC, and 4 had similar numbers for mayflies 

(23.5–37.8) and percent mayflies (34.3–38.2 percent). 

The highest EPT abundance was at site 1 (93.3). Site 3-

BC had the highest percent EPT (82.4 percent) due to the 

large number of stoneflies collected there, followed by 

site 1 (77.6 percent). EPT richness was the same (12.0) at 

sites 1 and 3-BC.

The same nine benthic macroinvertebrate community 

metrics were evaluated for samples collected in September 1999 as for the April 1999 samples. Samples collected in September showed a substantial overall 

decrease from April in mean abundance and taxa richness, so that statistical differences were minimized 

among the nine metrics (table 15). For samples collected 

in September, six of the nine benthic macroinvertebrate 

metrics were determined to be statistically different from 

normal (Shapiro-Wilk Test, α=0.05); data transformation 

increased the number of metrics that were distributed 

normally from three to five. An ANOVA (α=0.05) was 

conducted on the normal data while nonparametric statistics were used to analyze data that did not meet the 

assumption of normality (NPAR1Way ANOVA, α=0.05) 

(table 15). An NPAR1Way analysis was conducted on 

both the transformed and untransformed data that failed 

the assumption of normality. As in April, a General Linear Model (GLM, α=0.05) on ranked data was used to 

determine whether there were significant relations 

among all sites in September (LSD, α=0.05) (table 16).

The ANOVA determined that there were significant 

differences among sites for four of the five metrics that 

were tested parametrically, including caddisfly abundance, EPT abundance, percent EPT abundance, and 

EPT richness. The NPAR1Way ANOVA (α=0.05) on 

transformed data determined that there were significant 

differences among all four metrics analyzed nonparametrically, including total abundance, stonefly abundance, 

mayfly abundance, and percent mayfly abundance. In 

summary, the results of both parametric and nonparametric ANOVAs revealed significant differences among all 

benthic macroinvertebrate metrics sampled in September, 

except for taxa richness.

Site 4 was ranked highest (least degraded) for five of 

the nine benthic macroinvertebrate metrics, with site 3-

BC ranked highest four times (table 16). Site 2 was 

ranked lowest for all nine parameters, and was significantly lower than the other parameters four of nine times. 

Mean abundance was highest at site 3-BC (35.5) and site 

4 (33.5), and both sites had the highest mean taxa richness (11.3) (table 17). Sites 3-BC and 4 were higher than 

the other sites for caddisfly abundance, stonefly abundance, EPT abundance, percent EPT abundance, and 

EPT richness. The organisms that were collected in September at site 2 were similar to those collected in April, 

and included organisms in the families Corydalidae, Sialidae, Dytiscidae, Hydrophilidae, and Tipulidae. The 

dipteran Ptychoptera (Ptychopteridae) continued to have 

the highest abundance followed by chironomids (Chironomidae) and snails (Physidae).

Comparisons of April and September samples 

showed that mean abundance was reduced at all sites in 

September except site 2 where mean abundance (12.5) 

was the same as in April 1999 (table 17). Site 2, however, 

was still lower than all other sites in mean abundance and 

taxa richness; again, no caddisflies, stoneflies or mayflies 

were collected. The decrease in the number of organisms 

collected in September compared with April 1999 probably was due to the extremely dry conditions from June to 

September. These differences may also be due to natural 

seasonal variance in organism emergence and (or) migration downstream in summer. Limited flow and reduced 

dilution capacity typically contribute to low survival and 

reproduction during the summer months.
Ecotoxicology 37

Benthic macroinvertebrate

metric

Mean values

Site 1 Site 2 Site 3 Site 3-BC Site 4

Abundance 120 12.5 69.5 99.5 97.0

Taxa richness 18.8 3.0 13.5 16.0 13.0

Caddisfly abundance 15.5 0.0 4.75 10.0 2.5

Stonefly abundance 12.8 0.0 15.0 34.5 3.75

Mayfly abundance 65.0 0.0 23.5 37.8 33.3

Percent mayfly abundance 54.1 0.0 35.3 38.2 34.3

EPT abundance 93.3 0.0 43.3 82.3 39.5

Percent EPT abundance 77.6 0.0 63.7 82.4 40.7

EPT richness 12.0 0.0 8.5 12.0 9.75

Table 14. Mean values of benthic macroinvertebrate community metrics at each site for 

samples collected at Blue Ridge Parkway sampling sites in April 1999

[EPT, Ephemeroptera/Plecoptera/Trichoptera]

Benthic macroinvertebrate 

metric

Normality

(Shapiro-Wilk 

Test, (α=0.05)

Normality after 

transformation

(α=0.05)

ANOVA

(α=0.05)

NPAR1Way 

ANOVAa

(α=0.05)

NPAR1Way 

ANOVAb

(α=0.05)

Abundance 0.0002 0.0371c n.a. 0.0437 0.0436

Taxa richness 0.1392 Not needed 0.1254 n.a. n.a.

Caddisfly abundance 0.0002 0.0555c 0.0139 n.a. 0.0740

Stonefly abundance 0.0001 0.0188c n.a. 0.0411 0.2323

Mayfly abundance 0.0021 0.0267c n.a. 0.0259 0.1005

Percent mayfly abundance 0.0111 0.0091d n.a. 0.0139 0.0141

EPT abundance 0.0002 0.2073c 0.0030 n.a. 0.1548

Percent EPT abundance 0.1163 Not needed 0.0001 n.a. n.a.

EPT richness 0.1711 Not needed 0.0019 n.a. n.a.

Table 15. Statistical analysis of benthic macroinvertebrate metrics for samples collected at Blue Ridge Parkway sampling sites 

in September 1999

[ANOVA, analysis of variance; NPAR1Way ANOVA, nonparametric one-way analysis of variance; EPT, 

Ephemeroptera/Plecoptera/Trichoptera; α, probability of incorrectly rejecting the null hypothesis; <, actual value is 

known to be less than value shown; n.a., not applicable]

a

 Statistics conducted on transformed data

b

 Statistics conducted on untransformed data

c

 Square root transformation

d Percent arcsine (Asin) square root transformation
38 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Benthic macroinvertebrate 

metric

Ranking of Sites

High Low

Abundance 3-BC 4 3 1 2

Taxa richness 4 3-BC 1 3 2

Caddisfly abundance 4 3-BC 1 3 2

3-BC 1 3

Stonefly abundance 3-BC 4 1 3 2

1 3

Mayfly abundance 3-BC 3 4 1 2

Percent mayfly abundance 3-BC 3 4 1 2

4 1

EPT abundance 4 3-BC 3 1 2

Percent EPT abundance 4 3-BC 2

3-BC 1 3

EPT richness 4 3-BC 1 3 2

Table 16. Ranking and statistical analysis of sites for nine benthic macroinvertebrate 

metrics at Blue Ridge Parkway sampling sites in September 1999.

[Sites are ranked from high to low for each metric with high values generally associated with 

good water-quality conditions. Each outlined dark gray block contains a group of sites that do 

not differ significantly from each other. Light gray blocks contain an individual site that is 

significantly different from other sites; EPT, Ephemeroptera/Plecoptera/Trichoptera]

Benthic macroinvertebrate

metric Site 1 Site 2 Site 3 Site 3-BC Site 4

Abundance 27.3 12.5 29.3 35.5 33.5

Taxa richness 10.8 5.75 10.3 11.3 11.3

Caddisfly abundance 5.0 0.0 3.5 7.75 14.5

Stonefly abundance 4.25 0.0 3.0 10.3 5.75

Mayfly abundance 1.0 0.0 4.25 5.0 3.5

Percent mayfly abundance 2.5 0.0 14.4 14.5 10.6

EPT abundance 10.3 0.0 10.8 23.0 23.8

Percent EPT abundance 38.2 0.0 35.3 56.2 66.9

EPT richness 5.0 0.0 3.75 6.5 6.75

Table 17. Benthic macroinvertebrate community metric averages at each site for samples collected 

in September 1999

[EPT, Ephemeroptera/Plecoptera/Trichoptera]
Ecotoxicology 39

Habitat Assessment

Habitat assessment was conducted in September 

1999 at the five sampled sites and at the Sinking Creek 

reference site. The Sinking Creek reference site was 

rated Excellent, and sites 1, 3, and 4 were rated Good to 

Excellent, reflecting the similarity in habitat among 

these sites (table 18). These three sites are slightly 

impaired by sediment-laden runoff from the headwater 

regions of both the unnamed stream and the sampled 

tributary. Site 3-BC was rated Good, but received a lower 

score (100) due to sediment loading and scouring below 

the confluence of the sampled tributary and the unnamed 

stream.

Site 2, which is affected by extensive erosion along 

both stream banks and adjacent riparian zones, was rated 

Fair. Stream bank erosion at site 2 results from storm 

flow through the overflow pipe that extends down the 

embankment from the landfill sedimentation pond as 

well as from the sides of the embankment and outer 

perimeter of the landfill property. Temporary retaining 

fences and riprap installed at the base of the embankment 

have offered minimal protection against erosion. Under 

storm conditions, the sampled tributary receives base 

flow from ground water as well as overflow water from 

the sedimentation pond once it reaches holding capacity 

from the surrounding landfill surface. This increased 

flow and volume of water have eroded and destabilized 

the stream banks.

Field Measurements

Field measurements were made on water samples 

collected from the 4-in. PVC pipe at site 2 between 

November 1998 and November 1999 (table 19). The 

samples appeared to have little or no turbidity, but at 

times had a pungent odor. Specific conductance values 

ranged from 510 to 850 μS/cm2

; DO concentration was 

highest in July (6.0 mg/L) and lowest in August and 

November (3.6 mg/L). Values for pH ranged from a high 

of 7.6 in December to a low of 5.8 in August. Alkalinity 

determined in samples returned to the laboratory varied 

from 326 to 380 mg/L as calcium carbonate except for a 

value of 160 mg/L, determined after the water sample 

was aerated for use in a chronic toxicity test. Flow from 

the 4-in. pipe was measured using a stopwatch and a 1-L 

bottle, and ranged from a low of 0.0012 ft3

/s in August 

and November 1999 to 0.0021 ft3

/s in July 1999. 

Water Column Toxicity Testing

Acute 48-hr water column toxicity tests were conducted 11 times, between November 1998 and November 1999, using water collected from the 4-in. PVC pipe 

at site 2. LC50 values ranged from 45.6 to 84.1 at 100-

percent sample concentration (table 20). The water sample from site 2 was considered acutely toxic in 10 of the 

11 tests when a 48-hr LC50 value was generated. All 11 

acute tests had at least 30-percent mortality at 100-percent sample concentration, with the greatest mortality 

occurring in March and November 1999 when 90 percent 

of the test organisms died.

Chronic toxicity endpoint values, the "no observable 

adverse effects concentration" (NOAEC) and "lowest 

observable adverse effects concentration" (LOAEC) for 

survival and reproduction, were determined for C. dubia

exposed over a 7-day period to water from site 2 (Fisher's 

Exact Test, Steel's Many-One Rank Test, α=0.05). The 

NOAEC is the lowest test concentration of the water 

from the PVC pipe at site 2 that was considered to be 

nontoxic for either survival or reproduction. The 

NOAEC for survival was 25-percent sample concentration and 12.5 percent for reproduction. This means that 

12.5 parts of water from site 2 was diluted with 87.5 

parts dilution water to cause no toxic effect to reproduction for the test organisms. The LOAEC indicated that 

survival of test organisms was impaired at 50-percent 

Site 

Habitat

assessment 

score

Rating Observations

Site 1 107 Good to Excellent Some sediment deposition in pools

Site 2 59 Fair Heavy sedimentation and erosion of banks

Site 3 107 Good to Excellent Some sediment deposition in pools

Site 3-BC 100 Good Some sediment deposition and scouring

Site 4 107 Good to Excellent Some sediment deposition in pools

Sinking Creek reference site 117 Excellent No visible signs of impairment

Table 18. Habitat assessment of sites sampled near the Blue Ridge Parkway, September 1999, and for the Sinking Creek reference 
40 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

l

Date

Water 

temperature,

in oC

Specific 

conductance,

in μS/cm 

Dissolved oxygen 

concentration,

in mg/L

pH, in

standard 

units

Alkalinity, in 

mg/L

Discharge from 

PVC pipe, in ft3

/s

11/29/98 – 600 – 6.3 326 0.0015

12/9/98 – 510 5.3 7.6 – –

2/18/99 – 700 5.8 6.0 360 0.0015

2/19/99 – 700 4.8 6.0 340 –

3/12/99 – 720 4.8 6.1 340 0.0015

*4/26/99 – 690 – 6.5 160a –

6/18/99 – 670 4.8 6.0 – 0.0015

7/24/99 18.8 690 6.0 6.1 – 0.0021

7/30/99 18.9 650 6.0 6.1 380 0.0021

8/2/99 18.7 620 4.2 5.8 360 –

8/26/99 17.5 660 3.6 6.0 330 0.0012

9/6/99 18.9 750 4.0 5.9 360 0.0018

*9/8/99 – – – – – –

10/14/99 18.0 750 4.0 6.0 352 0.0015

11/28/99 17.0 850 3.6 6.0 360 0.0012

Table 19. Field measurements made in association with collection of water from the polyvinyl chloride pipe at 

site 2 for toxicity tests

[

oC, degrees Celsius; μS/cm, microsiemens per centimeter, mg/L, milligrams per liter; PVC, polyvinyl chloride; 

ft3/s, cubic feet per second; *, date when water chemistry, bottom sediment chemistry and benthic invertebrate 

samples were collected; –, no measurement made]

a

Sample aerated prior to alkalinity measurement

Test date LC50 value Estimated discharge, in 

ft3

/s

Test conducted

Mortality in 100-percent 

sample concentration, in 

percent 

11/29/98 84.1 0.0015 Full acutea 65

1/26/99 72.6 .0014 Full acute 80

2/18/99 84.1 .0015 Full acute 65

3/12/99 45.6 .0015 Range findingb 90

6/18/99 None .0015 Full acute 30

7/23/99 72.6c .0021 Range finding 80

7/30/99 73.5 .0021 Full acute 80

8/26/99 70.7 .0012 Full acute 85

9/6/99 76.5 .0018 Full acute 80

10/14/99 74.9 .0015 Full acute 75

11/28/99 70.7 .0012 Full acute 90

Table 20. Results of 48-hour acute toxicity tests for water samples collected from the polyvinyl chloride pipe near site 2, 

Blue Ridge Parkway, Virginia

[LC50 value, the concentration that causes 50-percent mortality of the test organisms after a defined period of exposure; ft3/s, 

cubic feet per second]

a

Full acute test is composed of five different dilutions of sample water and one control; four replicates are done, each with 20 organisms

bRange finding test is composed of 100-percent and 50-percent sample water and one control, and is used in determining a range of 

toxicity in preparation for the next full acute test

c

Approximate LC50 value estimated from 80-percent mortality in a 100-percent water sample
Summary and Conclusions 41

site sample concentration, and reproduction was affected 

at 25-percent sample concentration.

Sediment Toxicity Testing

In April 1999, Chironomus (midge) survival ranged 

from 64 percent at site 4 to 98 percent at both site 1 and 

at the Sinking Creek reference site (table 21). Survival 

for chironomids in sediments at sites 3 and 4 was significantly lower (Fisher's Exact Test, α=0.05) than at the two 

reference sites.

Chironomid weight ranged from 3.60 mg at site 4 to 

4.04 at Sinking Creek and 4.49 mg at site 1. The mean 

midge weight at site 2 was 3.72 mg. No significant differences were found among sites for chironomid weight 

(Dunnett's Test, α=0.05).

At site 2, survival was high (80 percent), and mean 

weight was comparable to that at other sites, including 

the Sinking Creek reference site. Ceriodaphnia had substantial mortality to the sample from site 2 after 2 days, 

while Chironomus survival was high after a 10-day test 

exposure. This suggests that the midge was highly tolerant to the conditions at site 2.

Daphnia survival of sediment toxicity tests in April 

ranged from 100 percent using Sinking Creek sediment 

and sediment from site 3, to 87.5 percent using sediment 

from sites 1, 2, and 4 (table 22) with no significant differences found among sites for survival (Fisher's Exact 

Test, α=0.05). D. magna reproduction was significantly 

lower at site 2, however, than at the other three sampling 

sites and at the Sinking Creek site. The mean number of 

neonates ranged from a high of 27.1 using Sinking Creek 

sediments to a low of 16.8 using sediment from site 2 

(Dunnett's Test, α=0.05). D. magna has been reported to 

be a more sensitive test organism to environmentally 

stressed conditions than C. tentans (Yeager, 1994). That 

difference in sensitivity was confirmed in this study.

For samples collected in September, D. magna survival in the Sinking Creek reference sediments was 100 

percent, with survival at 87.5 percent at sites 1 and 3, and 

75 percent at site 4. No significant differences were 

observed among these four sites for survival. D. magna

survival was significantly lower at site 2 at only 37.5 percent.

Mean neonate production in September ranged from 

a high of 23.1 in sediments and water from Sinking 

Creek to 13.4 at site 3. Sites 1 and 4 were similar, with 

18.9 and 18.8 neonates produced, respectively (table 22). 

Site 2 had the lowest neonate production (6.25) and was 

significantly different from the other sites for reproduction. Toxicity testing using Chironomus was not conducted in September 1999 due to poor organism 

condition prior to testing.

Summary and Conclusions

Until its closure in 1995, the primary landfill for 

Roanoke City and County, Va., situated near the Blue 

Ridge Parkway, received a variety of solid wastes for 

nearly 20 years. This report presents the results of a 

study by the U. S. Geological Survey and Virginia Polytechnic Institute and State University, in cooperation 

with the National Park Service, to examine the effects of 

the closed landfill on the water chemistry, the streambed 

sediment chemistry, and the benthic macroinvertebrate 

community of an unnamed stream and a tributary to that 

stream. The primary water source for the tributary is a 4-

inch polyvinyl chloride (PVC) pipe, which protrudes 

from the slope at the base of the embankment bordering 

the landfill. An expanse of precipitate in the stream near 

the PVC pipe indicated unusual stream conditions. The 

tributary flows through National Park Service land, and 

merges with the unnamed stream prior to discharging 

into the Roanoke River. Stream discharge was measured 

and water and streambed sediment samples collected at 

four sites on the stream and its tributary in April and 

September 1999. Water samples were analyzed for major 

ions, nitrate, total and dissolved metals, total dissolved 

solids, total organic carbon, and volatile and semivolatile 

organic compounds, including organochlorine pesticides 

and polychlorinated biphenyls (PCBs). Streambed sediment samples were analyzed for total metals, total 

organic carbon, percent moisture, and volatile and semivolatile organic compounds, including organochlorine 

pesticides and PCBs.

Field ecotoxicological measurements were made at 

the four sites sampled for water and streambed sediment 

and at one additional site; habitat quality was assessed 

and benthic macroinvertebrates were collected and evaluated using the Rapid Bioassessment Protocols of the 

U.S. Environmental Protection Agency. Water samples 

collected from the 4-inch PVC pipe at site 2, and sediment samples collected at site 2 from November 1998 to 

November 1999 were used to conduct 48-hour acute and 

7-day chronic toxicity tests using selected laboratory test 

organisms. Two 10-day chronic toxicity tests of streambed sediments collected near the discharge pipe also 

were conducted.

In April, concentrations of 79 percent of inorganic 

constituents detected in water samples were higher at the 

site nearest the landfill than at all other sites, while in 
42 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Site

April September

Survival, 

in 

percent

Significant

(α =0.05)

Mean 

number of

neonates

Significant

(α =0.05)

Survival,

in

percent

Significant

(α =0.05)

Mean 

number of

neonates

Significant

(α =0.05)

Site 1 87.5 No 20.4 No 87.5 No 18.9 No

Site 2 87.5 No 16.8 Yes 37.5 Yes 6.25 Yes

Site 3 100 No 24.1 No 87.5 No 13.4 No

Site 4 87.5 No 19.4 No 75 No 18.8 No

Sinking Creek 

reference site 100 No 27.1 No 100 No 23.1 No

Table 22. Daphnia magna percent survival and mean neonate production, from 10-day chronic toxicity tests of streambed sediment samples collected near 

the Blue Ridge Parkway, and at the Sinking Creek reference site, April and September 1999

Site Survival,

in percent

Significant

(α =0.05)

Mean weight, 

in mg

Significant

(α =0.05)

Site 1 98 No 4.49 No

Site 2 80 Yes 3.72 No

Site 3 100 No 4.03 No

Site 4 64 Yes 3.60 No

Sinking Creek reference site 98 No 4.04 No

Table 21. Chironomus tentans percent survival and mean weight, from 10-day chronic toxicity tests of streambed sediment 

samples collected near the Blue Ridge Parkway, and at the Sinking Creek reference site, April 1999

[mg, milligrams]
Summary and Conclusions 43

September, highest concentrations were distributed 

between the landfill site (52 percent) and the next site 

downstream (42 percent). This is an indication that constituents were discharged from the landfill into the 

stream. The changed distribution of constituents in September may be a result of a storm that occurred two days 

before sampling, although prior to sampling, water levels 

had returned to low levels that had existed prior to the 

storm. Water at the site near the landfill showed little 

change in median concentrations of total metals, dissolved metals, and nonmetals from April to September, 

and had low dissolved oxygen and relatively low pH, 

indicating a consistent ground-water source for these 

constituents. Concentrations of many inorganic constituents in water remained higher at the farthest downstream 

site than the reference site in April and September.

In contrast, concentrations of constituents associated 

with sediment were lowest near the landfill in April and 

increased at downstream sites. These conditions were 

probably a consequence of low pH-low dissolved oxygen 

waters within the landfill that allowed some inorganic 

constituents (such as metals) to remain in solution near 

the landfill, resulting in low concentrations in the streambed sediments until exposed to atmospheric oxygen. The 

constituents in solution precipitated out onto sediment 

particles and the streambed itself as the dissolved oxygen 

concentration increased downstream; the highest concentrations for 59 percent of constituents detected in streambed sediment in April, including lead, zinc, and copper, 

occurred at the site farthest downstream, near the 

Roanoke River. In September, 60 percent of higher constituent concentrations associated with sediment were 

closest to the landfill, and concentrations of many constituents decreased downstream. Higher streamflows 

resulting from the storm prior to sampling probably 

scoured out the pool and the surficial layer of precipitate 

near the landfill along with the streambed. This redistribution of sediments may have disrupted the water-sediment chemical equilibrium.

Most of the 17 organic compounds detected in water 

were at the site near the landfill. Organic constituents 

detected were primarily industrial and (or) manufacturing solvents, and included volatile organic and semivolatile organic compounds, some of which had been 

detected in ground-water monitoring wells at the periphery of the landfill. Because of their volatility, the compounds were not detected in water at sites downstream of 

the landfill. A total of 17 discrete organic compounds 

were detected in sediment samples in either April or September, and concentrations of most were below their 

respective reporting limits. Organic compounds detected 

above their reporting limits in sediment in April included 

trichloroethene and tetrachloroethene, along with their 

degradation products, 1, 1-dichloroethane and 1,2-

dichloroethene, at the site near the landfill; and 4,4' DDT, 

at the most downstream site. In September, 4,4' DDT was 

detected at the site closest to the landfill.

The site closest to the landfill (site 2) not only 

showed limited macroinvertebrate abundance but also 

had minimal taxa richness (0-3 in April and 5.75 in September 1999). Contaminated sediments impaired the 

habitat quality, thus reducing numbers of the most sensitive insect orders. Mayflies (Ephemeroptera), stoneflies 

(Plecoptera) and caddisflies (Trichoptera), or EPT, were 

especially affected. The benthic macroinvertebrate community also appeared to be affected at the site on the 

sampled tributary just before the confluence with the 

unnamed stream (site 3), especially in April 1999, with 

only 58 percent of the abundance there relative to the reference site. In the September 1999 sampling, however, 

abundance and taxa richness metrics were slightly higher 

at this site than at the reference site, perhaps due to the 

limiting drought conditions at the reference site. There 

was no detectable difference in the macroinvertebrate 

community metrics along the unnamed stream from site 

1 to site 3-BC to site 4 for either sampling period.

Overall, evaluation of nine benthic macroinvertebrate 

community metrics indicated significant effects on the 

macroinvertebrates only at the site closest to the landfill. 

The main groupings of macroinvertebrates found at this 

site consisted of snails, worms, and dipterans, all representing tolerant taxa; the sensitive EPT orders were 

absent. All benthic macroinvertebrate community metrics indicated significantly better conditions at the reference site in comparison to the site nearest the landfill. 

The reference site averaged as many as 93.2 organisms, 

ranging from 84 to 102 among four replicate samples. 

Acute toxicity tests indicated toxic conditions in water 

samples from the 4-inch PVC pipe 10 out of 11 times 

between November 1998 and November 1999. Test 

organism mortality in water samples from the landfill at 

100-percent concentration ranged from 65 to 90 percent 

and generated 48-hr LC50 values from 45.6 to 84.1 percent. Chronic water-column testing indicated impairment 

of Ceriodaphnia dubia at 50-percent sample concentration, with reproductive impairment occurring down to 

25-percent sample concentration. Results from sediment 

toxicity tests with Daphnia magna indicated significant 

differences for reproduction in sediment from the site 

close to the landfill in relation to the others in the watershed. The three most notable factors indicating stressed 

and (or) impacted conditions in the stream near the land-
44 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

fill consisted of (1) the layer of fine metal oxide precipitate in the streambed at and below the site nearest the 

landfill; (2) the significantly depressed numbers of 

benthic macroinvertebrates, particularly of sensitive or 

pollution-intolerant groups; and (3) the consistent acute 

toxicity of water to Ceriodaphnia dubia. 
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Appendixes 47

Appendixes 1-6
48 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Analyte Method

number

Reporting

limit,

in μg/L

Concentration, in μg/L

April September

Site 2

replicate

Method

blank

Equipment

blank

Site 2

replicate

Method

blank

Equipment

blank

Nonmetals

Dissolved solids, total 160.1 10,000 468,000 ND – 395,000 7a –

Organic carbon, total 9060 1,000 5,900 ND – 4,700 620a –

Chloride 300.0A 3,000 52,600b ND – 24,700 940c –

Fluoride 300.0A 1,000 240a ND – 230a ND –

Sulfate 300.0A 5,000 4,000a ND – 2,500a ND –

Metals

Aluminum, dissolved 6010B 100 54a 43a 53a ND ND ND

Aluminum, total 6010B 100 27a 52a – ND ND –

Antimony, dissolved 6020 2 ND 0.54a ND ND ND ND

Arsenic, dissolved 6020 5 1.1a ND ND 0.96a ND ND

Arsenic, total 6020 5 0.91a ND – 0.94a ND –

Barium, dissolved 6010B 10 540 ND ND 550 ND ND

Barium, total 6010B 10 540 ND – 560 ND –

Calcium, dissolved 6010B 200 70,300 ND ND 65,000 ND ND

Calcium, total 6010B 200 69,100 ND – 64,700 ND –

Cobalt, dissolved 6010B 10 22 ND ND 25 ND ND

Cobalt, total 6010B 10 19 ND – 26 ND –

Iron, dissolved 6010B 100 8,970 ND ND 11,700 10a 25a

Iron, total 6010B 100 9,100 7.7a – 11,700 ND –

Lead, dissolved 6020 1 0.13a ND ND 0.082a ND ND

Lead, total 6020 1 0.094a ND – ND ND –

Magnesium, dissolved 6010B 200 37,000 ND 14a 31,900 ND ND

Magnesium, total 6010B 200 36,200 24a – 31,800 ND –

Manganese, dissolved 6010B 10 3,200 ND ND 3,300 ND ND

Manganese, total 6010B 10 3,200 ND – 3,300 ND –

Potassium, dissolved 6010B 5,000 5,600 ND ND 4,700a ND ND

Potassium, total 6010B 5,000 5,400 ND – 4,800a ND –

Sodium, dissolved 6010B 5,000 36,000 600a 980a 23,400 680a 640a

Sodium, total 6010B 5,000 35,800 1,700a – 23,000 ND –

Vanadium, total 6010B 10 ND ND – 1.7a ND –

Zinc, dissolved 6010B 20 3.3a ND ND 6.1a ND 3.7a

Zinc, total 6010B 20 5.2a ND – 7a 3.5a –

Appendix 1. Results of quality assurance samples for inorganic constituents and organic carbon in water at Blue Ridge Parkway 

sampling sites, April and September 1999

[μg/L, micrograms per liter; ND, not detected; –, not analyzed]

a

 Estimated result-result is less than reporting limit

b Elevated reporting limit due to high analyte levels

c Associated method blank contains the target analyte at a reportable level
Appendixes 49

Analyte

Reporting 

limit,

in μg/L

Concentration, in μg/L

April September

Site 2 

replicate

Equipment 

blank

 Trip 

blank

Laboratory

method 

blank

Equipment 

blank

Trip 

blank

Laboratory 

method

blank

Method 8260B–Volatile organic compounds analyzed by GC/MS

1,1-Dichloroethane 2 28 ND ND ND ND ND ND

1,2-Dichloroethane 2 2.4 ND ND ND ND ND ND

cis-1,2-Dichloroethene 2 59 ND ND ND ND ND ND

trans-1,2-Dichloroethene 1 1.2 ND ND ND ND ND ND

1,2-Dichloroethene (total) 2 60 ND ND ND ND ND ND

1,2-Dichloropropane 2 2.5 ND ND ND ND ND ND

Benzene 2 9.7 ND ND ND ND ND ND

Chlorobenzene 2 0.72a ND ND ND ND ND ND

Chloroethane 4 5.4 ND ND ND ND ND ND

Ethylbenzene 2 8.2 ND ND ND ND ND ND

Methylene chloride 2 4.6 ND ND 0.37a ND 0.37a,b ND

Tetrachloroethene 2 8.1 ND ND ND ND ND ND

Toluene 2 18 ND ND ND ND ND ND

Trichloroethene 2 16 ND ND ND ND ND ND

Vinyl chloride 4 6.5 ND ND ND ND ND ND

Xylenes (total) 2 56 ND ND ND ND ND ND

Method 8270C–Semivolatile organic compounds analyzed by GC/MS

1,4-Dichlorobenzene 10 10 ND ND ND ND ND ND

Appendix 2. Quality assurance samples collected for organic constituents in water at Blue Ridge Parkway sampling stations, 

April and September 1999

[μg/L, micrograms per liter; GC/MS, gas chromatography/mass spectrometry]

a

 Estimated value-value is less than reporting limit

b Associated method blank contains the target analyte at a reportable level
50 Water and Streambed Sediment Quality, and Ecotoxicology of a Stream along the Blue Ridge Parkway

Analyte Method Units Reporting 

limit

April September

Laboratory 

method

blank

Site 2 

replicate

Laboratory

method

blank

Site 2 

replicate

Aluminum 6010B mg/kg 10 ND 3,630 ND 9,970a

Arsenic 6020 μg/kg 500 ND 1,190 – –

Arsenic 6020 mg/kg 10 – – ND 1.0

Barium 6010B mg/kg 1.0 ND 86.1 ND 113a

Beryllium 6010B mg/kg 0.2 ND 0.62 0.093b 1.5

Cadmium 6010B mg/kg 0.2 0.062b ND ND 0.55

Calcium 6010B mg/kg 20 ND 1260 ND 2,850a

Chromium 6010B mg/kg 1.0 ND 2.0 ND 9.5a

Cobalt 6010B mg/kg 1.0 0.22b 3.1 ND 5.3a

Copper 6010B mg/kg 2.0 ND 1.9b ND 5.7

Iron 6010B mg/kg 10 ND 38,500 2.6b 41,200

Lead 6020 μg/kg 100 ND 2,680 – –

Lead 6020 mg/kg 0.1 – – ND 8.6

Magnesium 6010B mg/kg 20 ND 628 ND 2,080a

Manganese 6010B mg/kg 1.0 ND 82.9 0.065b 193a

Mercury 7471A mg/kg 0.033 ND NDb ND 0.011b

Molybdenum 6010B mg/kg 2.0 ND 1.2b ND NDb

Nickel 6010B mg/kg 4.0 ND 1.9b ND 3.0

Potassium 6010B mg/kg 500 ND 263b ND 844

Selenium 6020 μg/kg 500 ND 173 – –

Selenium 6020 mg/kg 0.50 – – ND 0.15b

Silver 6010B mg/kg 1.0 ND 0.57b ND ND

Thallium 6020 ug/kg 100 ND 44.6 ND ND

Total Organic Carbon 9060 mg/kg 2,000 ND 36,800 ND 12,500

Vanadium 6010B mg/kg 1.0 ND 8.9 ND 25.7a

Zinc 6010B mg/kg 2.0 ND 34.7 ND 70.9a

Percent Moisture ASTM % 0.2 – 88.8 – 65.6

a

 Serial dilution of a digestate in the analytical batch indicates that physical and chemical interferences are present 

b Estimated result -result is less than reporting limit

Appendix 3. Results of quality assurance samples collected for inorganic constituents, total organic carbon, and percent 

moisture in streambed sediment at Blue Ridge parkway sampling sites, April and September 1999

[mg/kg, milligrams per kilograms; μg/kg, micrograms per kilogram; ND, not detected; – analysis not done or reported at 

different level for that constituent; ASTM, American Society of Testing and Materials]
Appendixes 51

Analyte Reporting 

limit

Concentration, in μg/kg

April September

Method 

blank

Site 2 

replicate

Method 

blank

Site 2 

replicate

Method 8260B–Volatile organic compounds analyzed by GC/MS

1,1-Dichloroethane 5.0 ND 15 ND 2.9a

1,2-Dichloroethene (total) 5.0 ND 12 ND 1.6a

1,2-Dichloropropane 5.0 ND 0.65a ND ND

Acetone 20 ND 11a ND ND

Benzene 5.0 ND 1.7a ND ND

Chloroethane 10 ND 1.7a ND ND

Chloroform 5 ND ND 1.3a ND

cis-1,2-Dichloroethene 2.5 ND 12 ND 1.6a

Methylene chloride 5.0 1.2a 2.7a,b 4.6a 0.79a,b

Tetrachloroethene 5.0 ND 16 ND ND

Trichloroethene 5.0 ND 7.0 ND 0.83a

Method 8270C–Semivolatile organic compounds analyzed by GC/MS

Aldol condensation product –c 32,000a ND ND ND

Method 8081A–Semivolatile organic compounds analyzed by GC (Organochlorine Pesticides)

beta-BHC 1.7 ND ND ND 0.8a

Appendix 4. Results of quality assurance samples collected for organic constituents in streambed 

sediment at Blue Ridge sampling sites, April and September 1999

[ug/kg, micrograms per kilogram; GC/MS, gas chromatography/mass spectrometry; ND, not detected; 

–, not determined]

a

 Estimated result-result is less than reporting limit

b Method blank contamination-the associated method blank contains the target analyte at a reportable level

c

 Result was measured against nearest internal standard assuming a response factor of 1
Taxon Family Genus Site 1 Site 2 Site 3 Site 3-BC 

A B C D TOT A B C D TOT A B C D TOT A B C D TOT A 

Gastropoda Physidae Physella 1 – 1 2 – – 7 3 10 – – – – – – – – – – – Oligochaeta – – – – – – 2 – 8 1 11 1 5 – 2 8 – – 1 – 1 – Decapoda Cambaridae – 2 3 3 3 11 – – – – – 3 – 2 1 6 – – 1 – 1 1 Collembola – – – – – – – – – – – – 1 – – – 1 – – – – – – Ephemeroptera Baetidae – – – – – – – – – – – – – – – – – – – – – – Ephemeroptera Baetidae Labiobaetis – – – – – – – – – – – 6 11 4 21 3 – 9 – 12 – Ephemeroptera Baetidae Paracloeodes 2 4 2 3 11 – – – – – – 7 24 31 2 2 2 2 8 2 Ephemeroptera Ephemeridae Ephemera – – – – – – – – – – – – 1 – 1 – 1 – – 1 – Ephemeroptera Ephemerellidae Ephemerella 21 38 22 27 108 – – – – – 3 4 1 7 15 16 23 16 27 82 7 Ephemeroptera Ephemerellidae Eurylophella 1 2 1 1 5 – – – – – – – 1 – 1 – 1 – – 1 2 Ephemeroptera Heptageniidae Stenonema 6 3 10 8 27 – – – – – 3 1 – – 4 7 5 4 5 21 – Ephemeroptera Leptophlebiidae Leptophlebia 1 2 – 1 4 – – – – – – – 1 1 2 4 – – – 4 – Ephemeroptera Siphlonuridae Ameletus 35 18 20 32 105 – – – – – – 1 11 7 19 4 17 1 – 22 12 Odonata Cordulegastridae Cordulegaster 5 2 4 4 15 – – – – – – 2 1 – 3 – – – – – – Odonata Gomphidae Stylogomphus – – – – – – – – – – – – 1 – 1 – – 1 – 1 – Plecoptera Capniidae – – – – – – – – – – – – – – – – 1 1 – – 2 – Plecoptera Nemouridae Amphinemura 5 4 6 5 20 – – – – – 10 19 22 3 54 10 31 4 40 85 1 Plecoptera Peltoperlidae Tallaperla 4 10 5 5 24 – – – – – – – 2 – 2 11 10 11 7 39 – Plecoptera Perlidae Acroneuria 1 2 1 2 6 – – – – – – – – – – 2 1 – – 3 – Plecoptera Perlidae Eccoptura – – – 1 1 – – – – – – – – – – 3 – 1 – 4 – Plecoptera Perlodidae Isoperla – – – – – – – – – – 1 1 2 – 4 2 1 2 – 5 – Megaloptera Corydalidae Nigronia 1 3 4 3 11 – – – – – – – – – – – – 1 1 1 – Megaloptera Sialidae Sialis – – – – – – – – – – 1 – – – 1 – – – – – – Trichoptera Brachycentridae – – – – – – – – – – – – – – – – – 2 – – 2 – Trichoptera Hydropsychidae Cheumatopsyche 6 7 8 7 28 – – – – – – 1 1 – 2 5 4 6 9 24 – Trichoptera Hydropsychidae Hydropsyche – – – – – – – – – – 3 – 10 1 14 – – – – – – Trichoptera Limnephilidae Pycnopsyche – – – – – – – – – – – – – – – – – – – – – Trichoptera Philopotamidae Wormaldia 1 2 2 2 7 – – – – – – – – – – – 1 2 – 3 1 Trichoptera Rhyacophilidae Rhyacophila 7 5 7 8 27 – – – – – 1 1 1 3 3 4 3 1 11 – Coleoptera Elmidae – – – – – 1 – – – – – – 1 – – 1 – – – – – – Coleoptera Hydrophilidae – – – – – – 1 – – – 1 – – – 1 1 – – – – – – Diptera Chironomidae – 10 10 12 8 40 1 6 – – 7 7 28 39 5 79 5 12 20 12 49 75 Diptera Ptychopteridae Ptychoptera – – – – – 2 12 3 4 21 – – – – – – – – – – – 

Appendix 5. Benthic macroinvertebrates collected at Blue Ridge Parkway sites and resultant summary statistics, April 1999[A-D, replicate identifier; TOT, replicate total; AVG, average; –, not found]
Diptera Simuliidae – 2 2 1 3 8 – – – – – – – – – – 1 – 2 – 3 – Diptera Tipulidae Antocha – – – – – – – – – – – – – – – – – – 1 1 – 

Diptera Tipulidae Tipula 4 5 6 4 19 – – – ––121 – 4 2 4 3 2 11 1 

Replicate and site totals 115 123 115 127 480 6 18 18 8 50 35 78 108 57 278 81 120 90 107 398 102 

Summary Statistic A B C D AVG A B C D AVG A B C D AVG A B C D AVG A 

Abundance 115 123 115 127 120 6 18 18 8 12.5 35 78 108 57 69.5 81 120 90 107 99.5 102 Taxa richness 19 19 18 19 18.75 4 2 3 3 3 12 13 17 12 13.5 17 17 19 11 16 9 Caddisfly (Trichoptera) abundance 14 14 17 17 15.5 – – – – – 4 1 12 2 4.75 8 11 11 10 10 1 Stonefly (Plecoptera) abundance 10 16 12 13 12.75 – – – – – 11 20 26 3 15 29 44 18 47 34.5 1 Mayfly (Ephemeroptera) abundance 66 67 55 72 65 – – – – – 6 19 26 43 23.5 36 49 32 34 37.75 23 Percent mayfly 57.39 54.47 47.82 56.69 54.09 0 0 0 0 0 17.14 24.35 24.07 75.43 35.25 44.44 40.83 35.55 31.77 38.15 22.54 EPT abundance 90 97 84 102 93.25 – – – – – 21 40 64 48 43.25 73 104 61 91 82.25 25 

EPT richness 12 12 11 13 12 – – – – – 6 8 12 8 8.5 14 15 12 7 12 6 

Percent EPT 78.26 78.86 73.04 80.31 77.62 0 0 0 0 0 60 51.28 59.25 84.21 63.68 90.12 86.66 67.77 85.04 82.4 24.5 

Taxon Family Genus

Site 1 Site 2 Site 3 Site 3-BC 

A B C D TOT A B C D TOT A B C D TOT A B C D TOT A 

Appendix 5. Benthic macroinvertebrates collected at Blue Ridge Parkway sites and resultant summary statistics, April 1999—Continued[A-D, replicate identifier; TOT, replicate total; AVG, average; –, not found]
Taxon Family Genus Site 1 Site 2 Site 3 Site 3-BC 

A B C D TOT A B C D TOT A B C D TOT A B C D TOT A 

Gastropoda Physidae Physella –––––11518–––––––––––

Oligochaeta – – – – 4 –4– 4––4–– 2 13––––––Decapoda Cambaridae – 1 4 7 2 14 – – – – – 9 5 2 – 16 4 3 6 2 15 1 Ephemeroptera Baetidae – ––––––––––– 1––1––––––Ephemeroptera Baetidae Labiobaetis ––1–1–––––– 2––2 5–– 38–Ephemeroptera Baetidae Paracloeodes – – 1 1––––– 6 3 3 – 12 – – 1–1–Ephemeroptera Ephemeridae Ephemera ––––––––––––––– 1–––1 1Ephemeroptera Ephemerellidae Ephemerella –––––––––––––––––––––Ephemeroptera Ephemerellidae Eurylophella ––––––––––––– 22––––––Ephemeroptera Heptageniidae Leucrocuta –––––––––––––––––– 11–Ephemeroptera Heptageniidae Stenonema – – 2–2–––––––––– 6 2 – 1 9 6 Odonata Calopterygidae Calopteryx ––––––––––––––– 4–––4–Odonata Cordulegastridae Cordulegaster – – 3 36––––– 3–– 14– 1––1–Odonata Gomphidae Stylogomphus – – 1 23––––– 1 1 3 16––––– 1Plecoptera Capniidae – –––––––––––––––––––––Plecoptera Leuctridae – – – 1 45–––––– 5––5– 1––1–Plecoptera Nemouridae Amphinemura –––––––––––––––––––––Plecoptera Peltoperlidae Tallaperla ––– 11–––––– 1 2 1 4 24 1 2 1 28 3 Plecoptera Perlidae Acroneuria ––––––––––––––– ––––– Plecoptera Perlidae Eccoptura – 2 5 29–––––––– 2 2 1 – 1 1 3 2Plecoptera Perlodidae Isoperla 2–––2–––––––– 1 1 5 3 – 19–Megaloptera Corydalidae Nigronia ––––– 1 – 2 14– 3 1–4 4 1 1 1 7 1 Megaloptera Sialidae Sialis –––––– 1 1–2––––– 1 1 2–4–Trichoptera Hydropsychidae Cheumatopsyche – – 1 34–––––– 8 3 3 14 12 – 1 6 19 6Trichoptera Hydropsychidae Hydropsyche – 1––1–––––––––– 6–––6 Trichoptera Limnephilidae Pycnopsyche 3 5 3 1 12 – – – – – – – – – – – – – – – – Trichoptera Odontoceridae – – 1 – 12––––––––––––––––Trichoptera Philopotamidae Wormaldia – 1––1–––––––––– 4–– 1 5 3 Trichoptera Rhyacophilidae Rhyacophila ––––––––––––––– 1–––1–Coleoptera Dytiscidae – ––––– 1–– 12–––––––––––Coleoptera Elmidae – ––– 22––––––– 1–1––––––Coleoptera Hydrophilidae – ––––––– 1–1 1 1 1–3––––––Coleoptera Psephenidae Psephenus – – 1–1–––––––– 1 1 1–––1 1Diptera Chironomidae – 12 4 5 5 26 3 1 3 5 12 6 5 9 8 28 10 4 1 1 16 5 Diptera Ptychopteridae Ptychoptera – 1 – 1 2 7 3 3 1 14 – – – – – – – – – – – Diptera Simuliidae – –––––––––––––––––––––

Appendix 6. Benthic macroinvertebrates collected at Blue Ridge Parkway sites and resultant summary statistics, September 1999[A-D, replicate identifier; TOT, replicate total; AVG, average; –, not found]
Diptera Tipulidae Antocha –––––––––––––22––––––Diptera Tipulidae Hexatoma 1 – 1 13––––––––––––––––Diptera Tipulidae Tipula 2 – 4 1 7 2 1––3– 2 3 1 6 2–––2 1 

Replicate and site totals 21 19 40 29 105 15 11 15 9 50 26 37 30 24 98 91 17 15 19 142 31 

Summary Statistic A B C D AVG A B C D AVG A B C D AVG A B C D AVG A 

Abundance 21 19 40 29 27.25 15 11 15 9 12.5 26 37 30 24 29.25 91 17 15 19 35.5 31 Taxa richness 6 8 15 14 10.75 6 6 6 5 5.75 6 12 11 12 10.25 17 9 8 11 11.25 12 Caddisfly (Trichoptera)abundance 3 8 4 5 5–––––– 8 3 3 3.5 23 – 1 7 7.75 9 Stonefly (Plecoptera)abundance 2 2 6 7 4.25 – – – – – – 6 2 4 3 30 5 3 3 10.25 5 Mayfly (Ephemeroptera) abundance

– – 4 – 1––––– 6 6 3 2 4.25 12 2 1 5 5 7 

Percent mayfly – – 10 – 2.5 0 0 0 0 0 23.07 16.21 10 8.33 14.4 13.18 11.76 6.67 26.31 14.48 22.58 EPT abundance 5 10 14 12 10.25 – – – – – 6 20 8 9 10.75 65 7 5 15 23 21 EPT richness 2 5 7 6 5 – – – – – 1 6 3 5 3.75 10 4 4 8 6.5 6Percent EPT 23.8 52.63 35 41.37 38.2 0 0 0 0 0 23.07 54.05 26.66 37.5 35.32 71.42 41.17 33.33 78.94 56.22 67.74 

Taxon Family Genus

Site 1 Site 2 Site 3 Site 3-BC 

A B C D TOT A B C D TOT A B C D TOT A B C D TOT A 

Appendix 6. Benthic macroinvertebrates collected at Blue Ridge Parkway sites and resultant summary statistics, September 1999—Continued[A-D, replicate identifier; TOT, replicate total; AVG, average; –, not found]