Prepared in cooperation with the U.S. Environmental Protection Agency


Surface-Water Hydrology and Quality at the Pike Hill 

Superfund Site, Corinth, Vermont, 

October 2004 to December 2005 

Scientific Investigations Report 2007–5003 

U.S. Department of the Interior 

U.S. Geological Survey 
Cover. Top right, photograph of mine workings at the Pike Hill Superfund site, Corinth, Vermont. Middle, photograph of mine waste at

the Pike Hill Superfund site, Corinth, Vermont. Lower left, photograph of Pike Hill Brook above Richardson Road near Corinth, Vermont.
Surface-Water Hydrology and Quality at the 

Pike Hill Superfund Site, Corinth, Vermont, 

October 2004 to December 2005

By Richard G. Kiah, Jeffrey R. Deacon, Nadine M. Piatak, Robert R. Seal II, 

James F. Coles, and Jane M. Hammarstrom

Prepared in cooperation with U.S. Environmental Protection Agency

Scientific Investigations Report 2007–5003

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

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Suggested citation:

Kiah, R.G., Deacon, J.R., Piatak, N.M., Seal II, R.R., Coles, J.F., and Hammarstrom, J.M., 2007, Surface-water hydrology and quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005: U.S. Geological 

Survey Scientific Investigations Report 2007–5003, 61 p. 
iii

Acknowledgments

The authors acknowledge the effort provided by Thor Smith and Ann Chalmers, U.S. Geological Survey, for their assistance in the collection of data. Thanks also are extended to Edward 

Hathaway, U.S. Environmental Protection Agency, and Karen Rice, U.S. Geological Survey, for 

their technical reviews of this report.

v

Contents

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

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

Purpose and Scope ..............................................................................................................................2

Description of the Study Area ............................................................................................................2

Methods of Data Collection and Analysis .................................................................................................5

Hydrologic Data.....................................................................................................................................5

Water-Quality Data...............................................................................................................................5

Benthic Macroinvertebrate Data.......................................................................................................5

Quality-Control Procedures ................................................................................................................6

Data Analysis and Statistical Methods.............................................................................................6

Surface-Water Hydrology ............................................................................................................................7

Surface-Water Quality ..................................................................................................................................7

Specific Conductance and pH............................................................................................................7

Major Ions and Trace Elements........................................................................................................14

Sulfate and Calcium ..................................................................................................................14

Aluminum and Iron ....................................................................................................................24

Cadmium, Copper, and Zinc......................................................................................................28

Effects of Spring Rains and Snowmelt on Constituent Concentrations and Loads.................28

Measured and Estimated Constituent Concentrations and Loads.............................................33

Effect of Wetlands on Chemical Constituents................................................................................41

Biological Assessment of the Pike Hill Brook Watershed....................................................................43

Benthic Macroinvertebrate Assemblages .....................................................................................43

Comparison of Assemblages with Vermont Bioassessment Metrics........................................47

Summary and Conclusions.........................................................................................................................51

References Cited..........................................................................................................................................52

Appendix 1. Taxa and Total Number of Macroinvertebrates for Samples Collected in the 

Pike Hill, VT, Study Area ................................................................................................................56

Appendix 2. Vermont Department of Environmental Conservation (VT-DEC) Bioassessment 

Metrics for Macroinvertebrate Assemblages...........................................................................61
vi

Figures

1. Map showing sampling site locations and site-identification numbers in the 

Pike Hill, VT, study area................................................................................................................3

2–4. Graphs showing:

2. The relation of daily mean streamflow to daily mean specific conductance 

at the three continuously monitored sites in the Pike Hill, VT, study area.................8

3. The relation of daily mean streamflow to daily mean pH at the three 

continuously monitored sites in the Pike Hill, VT, study area.......................................9

4. Distribution of (A) specific conductance, and (B) pH at the synoptic 

monitoring sites in the Pike Hill, VT, study area............................................................11

5. Boxplots showing a comparison of daily mean (A) specific conductance, and 

(B) pH among the three continuously monitored sites in the Pike Hill, VT, study area...13

6–9. Graphs showing:

6. The typical response of instantaneous specific conductance and pH to 

streamflow events at the three continuously monitored sites in the Pike Hill, 

VT, study area.....................................................................................................................15

7. (A) Daily mean streamflow and time distribution of water-quality samples, 

and (B) flow-duration curve with streamflow distribution of water-quality 

samples for Pike Hill Brook above Richardson Road near Bradford, VT, 

station 01139830, site 1......................................................................................................19

8. (A) Daily mean streamflow and time distribution of water-quality samples, 

and (B) flow-duration curve with streamflow distribution of water-quality 

samples for Pike Hill Brook at Pike Hill Road, west crossing, near Bradford, 

VT, station 01139833, site 4 ...............................................................................................20

9. (A) Daily mean streamflow and time distribution of water-quality samples, 

and (B) flow-duration curve with streamflow distribution of water-quality 

samples for Pike Hill Brook at Pike Hill Road near Bradford, VT, station 

01139838, site 5...................................................................................................................21

10–11. Maps showing:

10. (A) Median concentrations of sulfate, and (B) mean instantaneous loads of 

sulfate in relation to percentiles of the data at synoptic sampling sites in the 

Pike Hill, VT, study area.....................................................................................................22

11. (A) Median concentrations of calcium, and (B) mean instantaneous loads of 

calcium in relation to percentiles of the data at synoptic sampling sites in the 

Pike Hill, VT, study area.....................................................................................................23

12. Boxplots showing a comparison of (A) concentrations of sulfate, (B) instantaneous 

loads of sulfate, (C) concentrations of calcium, and (D) instantaneous loads of 

calcium among the three continuously monitored sites in the Pike Hill, VT, 

study area ....................................................................................................................................25

13. Maps showing (A) median concentrations of aluminum in relation to U.S. 

Environmental Protection Agency National Recommended Water Quality Criteria, 

and (B) mean instantaneous loads of aluminum in relation to percentiles of the 

data at synoptic sampling sites in the Pike Hill, VT, study area..........................................26

14. Boxplots showing a comparison of (A) concentrations of aluminum, (B) instantaneous 

loads of aluminum, (C) concentrations of iron, and (D) instantaneous loads of iron 

among the three continuously monitored sites in the Pike Hill, VT, study area ...............27
vii

15–16. Maps showing:

15. (A) Median concentrations of cadmium in relation to U.S. Environmental 

Protection Agency National Recommended Water Quality Criteria, and 

(B) mean instantaneous loads of cadmium relative to percentiles of the 

data at synoptic sampling sites in the Pike Hill, VT, study area.................................29

16. (A) Median concentrations of copper in relation to U.S. Environmental 

Protection Agency National Recommended Water Quality Criteria, and 

(B) mean instantaneous loads of copper relative to percentiles of the data 

at synoptic sampling sites in the Pike Hill, VT, study area..........................................30

17. Boxplots showing a comparison of (A) concentrations of cadmium, (B) instantaneous 

loads of cadmium, (C) concentrations of copper, (D) instantaneous loads of copper, 

(E) concentrations of zinc, and (F) instantaneous loads of zinc among the three 

continuously monitored sites in the Pike Hill, VT, study area..............................................31

18. Photographs showing streamflow conditions at site 1 during early snowmelt and 

rain (April 2, 2005) and snowmelt (April 11, 2005), and graphs showing the distribution 

of concentrations of copper and zinc in relation to maximum streamflows resulting 

from early snowmelt and rain (April 2 to 4, 2005), and from snowmelt (April 5 to 11, 

2005) at (A) Pike Hill Brook above Richardson Road near Bradford, VT, station 

01139830, site 1; and (B) Pike Hill Brook at Pike Hill Road near Bradford, VT, 

station 01139838, site 5...............................................................................................................32

19–28. Graphs showing:

19. The relation of measured to estimated concentrations of (A) calcium at the 

three continuously monitored sites in the Pike Hill, VT, study area; and (B) sulfate; 

(C) aluminum; (D) iron; (E) cadmium; (F) copper; and (G) zinc at Pike Hill Brook 

above Richardson Road near Bradford, VT, station 01139830, site 1 ........................35

20. Estimated daily mean concentrations of (A) calcium at the three continuously 

monitored sites in the Pike Hill, VT, study area; and (B) sulfate; (C) aluminum; 

(D) iron; (E) cadmium; (F) copper; and (G) zinc at Pike Hill Brook above 

Richardson Road near Bradford, VT, station 01139830, site 1, from November 

2004 to December 2005 .....................................................................................................36

21. Annual and seasonal loads for (A) sulfate, (B) calcium, (C) aluminum, (D) iron, 

(E) cadmium, (F) copper, and (G) zinc at the three continuously monitored sites 

in the Pike Hill, VT, study area..........................................................................................40

22. Concentrations of dissolved iron at synoptic sampling sites in the Pike Hill, VT, 

study area, August 3, 2005................................................................................................42

23. (A) Concentrations of dissolved sulfate, and (B) instantaneous loads of 

sulfate at sampling sites in the Pike Hill, VT, study area, August 3, 2005 .................44

24. (A) Concentrations of dissolved copper, and (B) instantaneous loads of 

copper at sampling sites in the Pike Hill, VT, study area, August 3, 2005.................45

25. (A) Concentrations of dissolved zinc, and (B) instantaneous loads of zinc at 

sampling sites in the Pike Hill, VT, study area, August 3, 2005 ...................................46

26. The relation of Hazard Index and (A) total abundance, (B) Mayfly plus caddisfly 

richness, and (C) Chironomid richness at sampling sites in the Pike Hill, VT, 

study area ...........................................................................................................................48

27. The relation between values of site deviation from reference and the 

Hazard Index values (log) at sampling sites in the Pike Hill, VT, study area............50

28. The relation of macroinvertebrate data at the Pike Hill, VT, study area to 

data from Vermont reference streams...........................................................................50
viii

Tables

1. Selected characteristics of sampling sites for the Pike Hill, VT, study area ......................4

2. Summary statistics of physical parameters from the three continuously monitored 

sites in the Pike Hill, VT, study area.........................................................................................10

3. Summary statistics of physical parameters for synoptic sampling sites in the 

Pike Hill, VT, study area..............................................................................................................12

4. Summary of the U.S. Environmental Protection Agency national recommended 

water quality criteria for priority and non-priority pollutants and the percentage of 

exceedance at the Pike Hill, VT, study area...........................................................................16

5. Summary statistics for concentrations of sulfate, calcium, aluminum, iron, 

cadmium, copper, and zinc in water samples and a stream-sediment sample 

collected at sites in the Pike Hill, VT, study area...................................................................17

6. Summary statistics of instantaneous loads of sulfate, calcium, aluminum, iron, 

cadmium, copper, and zinc in water samples collected at sites in the Pike Hill, VT, 

study area ....................................................................................................................................18

7. Regression equations for estimating concentrations of sulfate, calcium, aluminum, 

iron, cadmium, copper, and zinc at the three continuously monitored sites in the 

Pike Hill, VT, study area..............................................................................................................34

8. Summary statistics for estimated daily mean concentrations of sulfate, calcium, 

aluminum, iron, cadmium, copper, and zinc from regression models at the three 

continuously monitored sites in the Pike Hill, VT, study area..............................................38

9. Regression equations for estimating loads of sulfate, aluminum, iron, cadmium, 

copper, and zinc at Pike Hill Brook at Pike Hill Road, west crossing, and Pike Hill 

Brook at Pike Hill Road near Bradford, VT .............................................................................39

10. Annual and seasonal loads estimated for the three continuously monitored sites 

in the Pike Hill, VT, study area...................................................................................................41

11. Selected parameters for sampling sites associated with the wetlands in the 

Pike Hill, VT, study area, August 3, 2005..................................................................................42

12. Hazard index values and the Vermont Department of Environmental Conservation 

(VT-DEC) assessment of U.S. Geological Survey macroinvertebrate assemblage 

data for sites in the Pike Hill, VT, study area..........................................................................47
ix

Conversion Factors, Abbreviated Water-Quality Units, and 

Datums

Multiply By To obtain

Length

inch (in) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Flow

cubic foot per second (ft3

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

Area

square mile (mi2

) 2.590 square kilometer (km2) 

acre 0.004047 square kilometer (km2

)

pH: pH is given in standard units and may be converted to hydrogen-ion (H+) concentration as 

follows:

 H+=10(-pH)

Temperature: Temperature is given in degrees Celsius (°C) and may be converted to degrees 

Fahrenheit (°F) as follows:

 °F=(1.8×°C)+32

Abbreviated water-quality units used in this report: Chemical concentrations in water are 

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 as weight (milligrams) of chemical 

per unit volume (liter) of water. Micrograms per liter is a unit expressing the concentration 

of chemical constituents as weight (micrograms) of chemical per unit volume (liter) of water. 

Chemical loads in water are reported in kilograms per day (kg/d).

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25°C).

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Abstract

The hydrology and quality of surface water in and 

around the Pike Hill Brook watershed, in Corinth, Vermont, 

was studied from October 2004 to December 2005 by the 

U.S. Geological Survey in cooperation with the U.S. Environmental Protection Agency (USEPA). Pike Hill was mined 

intermittently for copper from 1847 to 1919 and the site is 

known to be contributing trace elements and acidity to Pike 

Hill Brook and an unnamed tributary to Cookville Brook. The 

site has been listed as a Superfund site since 2004. Streamflow, specific conductance, pH, and water temperature were 

measured continuously and monthly at three sites on Pike Hill 

Brook to determine the variation in these parameters over an 

annual cycle. Synoptic water-quality sampling was done at 10 

stream sites in October 2004, April 2005, and June 2005 and 

at 13 stream sites in August 2005 to characterize the quality of 

surface water in the watershed on a seasonal and spatial basis, 

as well as to assess the effects of wetlands on water quality. 

Samples for analysis of benthic macroinvertebrate populations 

were collected at 11 stream sites in August 2005.

Water samples were analyzed for 5 major ions and 32 

trace elements. Concentrations of trace elements at sites in the 

Pike Hill Brook watershed exceeded USEPA National Recommended Water Quality Criteria acute and chronic toxicity standards for aluminum, iron, cadmium, copper, and zinc. Concentrations of copper exceeded the chronic criteria in an unnamed 

tributary to Cookville Brook in one sample. Concentrations of 

sulfate, calcium, aluminum, iron, cadmium, copper, and zinc 

decreased with distance from a site directly downstream from 

the mine (site 1), as a result of dilution and through sorption 

and precipitation of the trace elements. Maximum concentrations of aluminum, iron, cadmium, copper, and zinc were 

observed during spring snowmelt. Concentrations of sulfate, 

calcium, cadmium, copper, and zinc, and instantaneous loads 

of calcium and aluminum were statistically different (p<0.05) 

among the three continuously monitored sites (sites 1, 4, 

and 5). Instantaneous loads of aluminum, iron, and copper 

decreased by one to three orders of magnitude from site 1 to a 

site 1.1 mi downstream (site 4). Instantaneous loads of sulfate 

were similar between sites 1, 4, and at a site 3 mi downstream 

(site 5). Instantaneous loads of cadmium and zinc were similar 

between sites 1 and 4, and loads of iron and copper were similar between sites 4 and 5.

Loads of chemical constituents were compared at site 1 

(closest to the mine waste piles) and site 5 (near the mouth 

of Pike Hill Brook and below a majority of the wetlands). 

Annually, the loads of dissolved cadmium and zinc at site 1 

were about five times greater than loads at site 5, and the load 

of dissolved copper at site 1 was about 17 times greater than at 

site 5. The ratio of loads for dissolved cadmium, copper, and 

zinc to total cadmium, copper, and zinc at site 1 was about 1. 

Samples collected in Pike Hill Brook upstream and 

downstream from the wetlands during low flows in August 

2005 showed that oxidation of ferrous iron and precipitation 

of iron-hydroxides were probably not affecting trace metals in 

the wetlands through sorption; however, a significant portion 

of the iron entering the wetlands was in particulate form and 

may have transported sorbed copper and other trace metals. 

Thus, aerobic activity in the wetlands was probably not affecting metal cycling in the watershed. Concentrations and loads 

of sulfate may be unlikely to define unequivocally the role of 

the wetlands with regard to anaerobic bacterial sulfate reduction; however, bacterial sulfate removal may have affected 

loads of sulfate. Loads of copper increased downstream from 

the wetlands and may reflect the reductive dissolution of ferric hydroxide particulates in anaerobic parts of the wetlands. 

Concentrations of dissolved iron increased downstream from 

the wetlands.

The most apparent effects on the macroinvertebrate 

assemblages caused by high levels of acid rock drainage were 

seen in the abundance of organisms and richness of taxa. A 

decrease in the macroinvertebrate abundance was strongly 

correlated to increasing values of the Hazard Index (rho = 

-0.929); this response was most apparent in the Pike Hill 

Brook sites farther from the mine waste piles. At sites most 

affected by acid rock drainage, stoneflies were not quite as 

sensitive as mayflies and caddisflies.

Surface-Water Hydrology and Quality at the Pike Hill 

Superfund Site, Corinth, Vermont, October 2004 to 

December 2005

By Richard G. Kiah, Jeffrey R. Deacon, Nadine M. Piatak, Robert R. Seal II, James F. Coles, and 

Jane M. Hammarstrom
Introduction

The Pike Hill Brook watershed is in the town of Corinth 

in eastern Vermont (fig. 1). Pike Hill was mined intermittently 

for copper from 1847 to 1919, and the site is known to be 

contributing trace elements and acidity to Pike Hill Brook and 

an unnamed tributary to Cookville Brook (U.S. Environmental 

Protection Agency, 2004). The Pike Hill Superfund Site was 

placed on the U.S. Environmental Protection Agency (USEPA) 

National Priorities List in 2004 and consists of three abandoned mines.

The Pike Hill mines are primarily on the top and northeastern exposures of Pike Hill, in an area referred to as the 

Vermont copper belt (fig. 1). This area contains the Eureka 

and Union mines. A smaller mine, the Smith mine, is on the 

southern exposure of Pike Hill. The Pike Hill site includes 

open mine cuts, trenches, adits, shafts, waste rock, and several 

small piles of flotation tailings.

Copper was discovered on Pike Hill sometime before 

1847 (U.S. Environmental Protection Agency, 2004). Mining 

at Pike Hill exploited Besshi-type massive sulfide deposits 

in the Waits River Formation (Silurian), which consists of 

calcareous pelite, pelite, minor quartzose metalimestone and 

metadolostone, and sparse calcite marble (Piatak and others, 

2006a). The bedrock at Pike Hill contains large amounts of 

carbonate minerals that may contribute alkalinity and hardness 

to local surface waters.

Trace elements released into local streams and rivers 

may be toxic to aquatic life and possibly to human health. The 

weathering of mine wastes further releases trace elements and 

sulfate into waterways, affecting the local water quality. Trace 

elements may be transported downstream as dissolved material 

or sorbed to particulate matter. Dissolved trace elements are 

mainly removed from waters by precipitation and sorption, 

especially with hydroxides formed from iron and aluminum 

(Kelly, 1988). Sorbed trace elements can settle out of the 

water column or be transported downstream depending on 

water velocity.

To understand the fate and transport of contamination 

associated with acid rock drainage (ARD) at the Pike Hill 

Superfund Site, the U.S. Geological Survey (USGS), in cooperation with USEPA, used an integrated (physical, chemical, 

and biological) approach to assess the hydrology and quality 

of waters in and around the Pike Hill Brook watershed. A 

streamflow- and surface-water-quality monitoring network 

was operated from October 2004 to September 2006. Waterquality samples were collected monthly from November 2004 

to September 2006. Biological samples were collected in 

August 2005. This report presents data collected from October 

2004 to December 2005, complements a companion study 

focused on the geochemistry of the solid mine wastes and 

drainage environments of the abandoned mine sites (Piatak 

and others, 2006a), and will be used by water-resources managers to help determine the nature and extent of contamination and what additional studies may be necessary to perform 

as part of a remedial investigation and feasibility study for 

cleanup of the Pike Hill Superfund Site.

Purpose and Scope

This report (1) characterizes the surface-water hydrology 

and water quality of Pike Hill Brook over an annual cycle; 

(2) provides estimates of annual and seasonal constituent loads 

in Pike Hill Brook; (3) describes the effects of natural wetlands on the water quality of Pike Hill Brook; and (4) explains 

the correlation of the benthic macroinvertebrate assemblage 

data with the water-quality data. The data presented in this 

report were collected at 14 stream sites from October 2004 

to December 2005 (fig. 1, table 1) and include streamflow; 

specific conductance; pH; water temperature; concentrations 

of sulfate (SO4

), calcium (Ca), aluminum (Al), iron (Fe), 

cadmium (Cd), copper (Cu), zinc (Zn); and benthic macroinvertebrate assemblages. Concentrations of Ca, Al, Cd, Cu, Fe, 

and Zn are presented in this report as dissolved unless noted as 

total. A dissolved sample is derived from a filtered (less than 

0.45 micron) water sample. Cd, Cu, and Zn are recognized 

as priority pollutants by the USEPA, whereas Al and Fe are 

considered non-priority pollutants.

Streamflow and water-quality data collected for the 

study are stored in the USGS National Water Information 

System (http://nwis.waterdata.usgs.gov/nwis). The taxonomic 

identification and count for benthic macroinvertebrates are 

listed in appendix 1. The State of Vermont Department of 

Environmental Conservation (VT-DEC) biocriteria metrics are 

listed in appendix 2.

Description of the Study Area

The study area, in the town of Corinth in east-central 

Vermont, is in the Connecticut River Basin (fig. 1). The area 

is mountainous with elevations ranging from about 1,190 ft at 

the mouth of Pike Hill Brook to 1,965 ft at the summit of Pike 

Hill (fig. 1). Mean annual precipitation varies with elevation 

and ranges from 39 to 42 in/yr (accessed at http://water.usgs.

gov/osw/streamstats/Vermont.html on June 5, 2005). The local 

mean annual temperature from 1971 to 2000 was 5.1o

C with 

a range of –2.2 to 12.3o

C (National Oceanic and Atmospheric 

Administration, 2002). Surface water from the northeastern 

exposure of Pike Hill discharges primarily to Pike Hill Brook. 

Pike Hill Brook originates near the mines and waste piles, has 

a total stream length of about 4.2 mi, and a contributing drainage area of 4.67 mi2 at the mouth (accessed at http://water.

usgs.gov/osw/streamstats/Vermont.html on June 5, 2005). Pike 

Hill Brook flows approximately 2.2 mi from its source before 

entering a series of natural wetlands and then flows approximately 2 mi before entering the Waits River (fig. 1). The 

wetlands constitute about 0.2 percent of the total drainage area 

or 0.83 mi2 (accessed at http://water.usgs.gov/osw/streamstats/

Vermont.html on June 5, 2005). A stream also drains the 

southern exposure of Pike Hill. This unnamed tributary flows 

approximately 1 mi to the confluence with Cookville Brook, 

which flows into the Waits River.

   Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Figure 1. Sampling site locations and site-identification numbers in the Pike Hill, VT, study area.

noC

cit

c

en

t u

R vi

re

Pike Hill Brook Pike Hill Brook

Cookville Brook Unnamed tributary to Cookville Brook

Union Mine

Montpelier

Concord

NEW

HAMPSHIRE

VERMONT

Study

Area

VermontCopperBelt

Eureka

Mine

Smith Mine

Pike

Hill

Base from U.S. Geological SurveyWest Topsham, 1981, 1:24,000 andEast Corinth, 1973, 1:24,000Vermont State Plane Coordinate System

0 0.25 0.5 0.75 1 MILE0 0.25 0.5 0.75 1 KILOMETER

2

0 1 2A

3

10

4

7

6

5 4A

5A

72° 17' 72° 15' 72° 13'

44°04'

44° 03'

9

8

EXPLANATION

 Synoptic sampling site with identification Continuous and synoptic sampling site with identification Additional sampling site with identification Mine

2

1

5A

Introduction 
Table 1. Selected characteristics of sampling sites for the Pike Hill, VT, study area.

[USGS, U.S. Geological Survey; Latitude and longitude are given in degrees°, minutes', and seconds"; mi2, square miles; L, August 2005 low-flow sampling site; B, benthic invertebrate sampling site; 

C, continuously monitored site; S, synoptic sampling site; ft, feet; mi, mile]

Site

number

(fig. 1)

Site name

USGS 

station 

number

Latitude Longitude

Drainage 

area

(mi2

)

Monitoring

status

Purpose of monitoring site

0 Pike Hill Brook below Eureka and Union 

mines near Bradford, VT

011398299 44°03'50" 72°18'18" 0.05

L Represented water-quality conditions directly downstream from the 

Eureka and Union mines and waste rock piles.

1 Pike Hill Brook above Richardson Road 

near Bradford, VT

01139830 44°03'50" 72°18'07" .11 B,C,S,L Represented water-quality conditions 800 ft downstream from 

site 0.

2 Tributary to Pike Hill Brook at 

Richardson Road near Bradford, VT

011398302 44°03'53" 72°18'06" .06 B,S,L Represented background water-quality conditions. Flows into 

Pike Hill Brook 100 ft downstream from site 1.

2A Pike Hill Brook at Richardson Road near 

Bradford, VT

01139831 44°03'49" 72°17'36" .36

L Represented water-quality conditions 0.5 mi downstream from site 1.

3 Pike Hill Brook at Carpenter Place near 

Bradford, VT

01139832 44°03'45" 72°17'19" .45 B,S,L Represented water-quality conditions 0.7 mi downstream from site 1 

after initial opportunity for precipitation and sorption of metals.

4 Pike Hill Brook at Pike Hill Road, west 

crossing, near Bradford, VT

01139833 44°03'28" 72°16'54" 1.10 B,C,S,L Represented water-quality conditions above the wetlands, 1.1 mi 

downstream from site 1.

4A Pike Hill Brook above wetlands near 

Bradford, VT

01139834 44°03'14" 72°16'26" 1.6

B Represented benthic invertebrate assemblages directly above the 

wetlands, 1.6 mi downstream from site 1.

5 Pike Hill Brook at Pike Hill Road near 

Bradford, VT

01139838 44°03'12" 72°15'12" 3.64 B,C,S,L Represented water-quality conditions after a majority of the 

wetlands, 3 mi downstream from site 1.

5A Tributary to Pike Hill Brook at Brook 

Road near Bradford, VT

011398378 44°02'54" 72°15'20" .26

L Represented background water-quality conditions. Flows into 

Pike Hill Brook 900 ft upstream from site 5. 

6 Pike Hill Brook at Miller Road near 

Bradford, VT

01139839 44°03'19" 72°14'45" 4.39 B,S,L Represented water-quality conditions below the wetlands, 3.8 mi 

downstream from site 1.

7 Pike Hill Brook at mouth near 

Bradford, VT

01139840 44°03'44" 72°14'06" 4.67 B,S,L Represented water-quality conditions at the mouth of Pike Hill 

Brook.

8 Waits River at VT 25 near 

Bradford, VT

01139826 44°04'38" 72°15'36" 42.7 B,S,L Represented background water-quality conditions, 1.8 mi 

upstream from confluence with Pike Hill Brook.

9 Waits River at Village Road near 

Bradford, VT

01139841 44°03'19" 72°13'18" 50.6 B,S,L Represented water-quality conditions 0.8 mi downstream from 

confluence with Pike Hill Brook.

10 Unnamed tributary to Cookville Brook 

near Bradford, VT

01139940 44°02'43" 72°17'56" .41 B,S,L Represented water-quality conditions down-gradient of Smith mine 

and in headwaters of unnamed tributary to Cookville Brook that drains the southern exposure of Pike Hill.

   Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Methods of Data Collection and 

Analysis

The sampling program for the study integrated physical, 

chemical, and biological data to assess water quality at 14 

stream sites: 9 sites on Pike Hill Brook, 2 sites on the Waits 

River, 2 sites on tributaries to Pike Hill Brook, and 1 site on 

a tributary to Cookville Brook (fig. 1, table 1). Three sites 

(sites 2, 5A, and 8) were selected to represent background 

water-quality conditions. Continuous monitoring of streamflow, specific conductance, pH, and water temperature was 

conducted at three sites (sites 1, 4, and 5) in Pike Hill Brook 

to characterize the variations in these parameters during 

an annual cycle. Water samples representing the different 

weather conditions that can affect constituent concentrations 

in samples, such as those observed from an increase in runoff 

during rain or snowmelt events, were collected monthly at the 

three continuously monitored sites. Synoptic water samples, 

representing a range in streamflows, were collected at 10 sites 

to assess the water quality of streams in and around the Pike 

Hill Brook watershed spatially and seasonally. Water samples 

were collected during summer low-flow conditions at 13 sites 

to evaluate the effects of the wetlands on the water quality of 

Pike Hill Brook (fig. 1, table 1). Benthic macroinvertebrate 

samples were collected during summer low-flow conditions at 

11 sites (table 1).

Hydrologic Data

Continuous record streamflow-gaging stations were 

established using protocols described in Rantz and others 

(1982). Records of stage were obtained using electronic data 

loggers and stage sensors. Stage readings were related to 

measurements of streamflow to obtain a stage-streamflow 

relation used in computing continuous streamflow. Continuous streamflow-gaging stations were at Pike Hill Brook above 

Richardson Road near Bradford, VT (USGS station 01139830, 

site 1), Pike Hill Brook at Pike Hill Road, west crossing, near 

Bradford, VT (USGS station 01139833, site 4), and Pike Hill 

Brook at Pike Hill Road near Bradford, VT (USGS station 

01139838, site 5) (fig. 1, table 1). Stage values were recorded 

every 5 minutes at site 1 and every 15 minutes at site 5 from 

October 2004 to December 2005. Stage values were recorded 

every 15 minutes at site 4 from June 2005 to December 2005. 

Instantaneous streamflow measurements were made at all 

water-quality synoptic sites. Streamflow was measured by 

the conventional current meter method, by use of a portable 

Parshall flume, volumetrically, or with an acoustic Doppler 

current profiler using published USGS protocols (Rantz and 

others, 1982; Buchanan and Somers, 1969; Kilpatrick and 

Schneider, 1983; and Oberg and others, 2005).

Water-Quality Data

Specific conductance, pH, and water temperature data 

were collected continuously at sites 1, 4, and 5 using published USGS protocols (Wagner and others, 2000). Values 

were recorded every 5 minutes at site 1 and every 15 minutes at site 5 from November 2004 to December 2005, and 

every 15 minutes at site 4 from June 2005 to December 2005. 

Water samples were collected using standard USGS protocols 

(Wilde and Radtke, 1998; Wilde and others, 1999) at sites 1 

and 5 from November 2004 to December 2005 and at site 4 

from June 2005 to December 2005. Additional samples were 

collected at sites 1 and 5 during spring rains and snowmelt. 

Four synoptic water samples were collected at sites 1 through 

9 during a range in streamflow conditions in November 2004, 

April 2005, June 2005, and August 2005. Three synoptic water 

samples were collected at site 10 in November 2004, June 

2005, and August 2005. The synoptic samples were collected 

to represent low, normal, and high streamflow conditions. 

Based on recorded streamflow at site 5, November samples 

represented the 75th percentile flow-duration, April samples 

represented the 5th percentile flow duration, June samples represented the 30th percentile flow duration, and August samples 

represented the 95th percentile flow duration. Flow-duration 

percentiles, in this usage, are the percentage of time a streamflow is expected to be equaled or exceeded at a given location. 

The April samples were used to describe high-flow conditions and are referred to in this report as the high streamflow 

samples. The August samples were used to describe low-flow 

conditions and are referred to in this report as the low streamflow samples. The median constituent concentration and mean 

instantaneous load of the four synoptic samples was used to 

describe normal streamflow samples.

Specific conductance, pH, and water temperature were 

determined by use of a combination of continuous monitors 

and discrete measurements at the time of water sample collection. Water samples were collected for the analysis of 5 major 

ions and 32 trace elements. All water samples were analyzed 

by the USGS Geologic Discipline Analytical Chemistry 

Services Group in Denver, CO. Major-ion and trace-element 

concentrations were analyzed using inductively coupled 

plasma-mass spectrometry unless otherwise noted. Sulfate 

concentrations were analyzed using ion chromatography.

Benthic Macroinvertebrate Data

Benthic macroinvertebrate samples were collected in 

August 2005 during low streamflows using a Slack sampler 

with a 500-micron mesh designed to cover 2.69 ft2

 (0.25 m2) 

of substrate area (Cuffney and others, 1993). At each site, 

macroinvertebrates were collected at four locations in a swiftflowing area of a sampling reach (typically riffles), and these 

four samples were composited to characterize the macroinvertebrate assemblage in a 10.76-ft2

 (1-m2) area of substrate. 

Under typical sampling situations, the USGS method 

Methods of Data Collection and Analysis   
recommends collections at five locations for a composite, 

thereby covering a substrate area of 13.45 ft2 (1.25 m2). The 

change to sampling 10.76 ft2

, however, was based on the 

method used by VT-DEC for high-gradient streams. The 

composited samples were preserved in 70-percent isopropyl 

alcohol and shipped to EcoAnalysts Inc., Moscow, ID, for a 

300-individual organism count for taxonomic identifications 

and metric calculations (abundance, dominance, richness, 

composition, functional feeding groups, diversity/evenness, 

and biotic indices).

Quality-Control Procedures

Daily mean streamflow computations were based upon 

records of stage and discrete measurements of streamflow 

in addition to observations of other factors, such as weather 

conditions, as described in Rantz and others (1982). The 

accuracies of the continuous streamflow and water-quality 

records listed in the appendixes are based on a scale of four 

classifications ranging from excellent to poor (Novak, 1985; 

Wagner and others, 2000).

Field quality-control procedures included the collection 

of blanks and replicates. Field blanks provide information on 

bias or the potential for contamination of analytical results by 

sample collection, processing, and analysis. Analytical results 

from the field-blank samples showed that concentrations for 

constituents presented in this report were less than the laboratory reporting level. Replicate samples provide information on 

the variability of analytical results caused by sample collection, processing, and analysis. Differences in concentrations in 

environmental and replicate samples for SO4

, Ca, Al, Fe, Cd, 

Cu, and Zn were less than 5 percent, so sample processing and 

analysis did not introduce enough variation in the environmental data to affect interpretation of results. Analytical laboratory 

quality-control procedures are summarized in Taggart (2002).

Data Analysis and Statistical Methods

Selected results from the three continuously monitored 

sites and the synoptic sampling sites are presented in the following sections and are shown as a series of graphs and plots 

used to analyze the data. Mean pH values for samples in this 

report were determined by converting instantaneous pH values 

to hydrogen-ion (H+

) concentrations, calculating the mean of 

the instantaneous H+

 concentrations, and converting the mean 

H+

 concentration back into pH units (Wagner and others, 

2000). Statview statistical software was used for all statistical 

analyses (SAS Institute, Inc., 1998).

A statistical analysis of the physical and water-quality 

parameters was conducted to investigate the fate and transport 

of constituents in Pike Hill Brook. The Kruskal-Wallis statistical test, a non-parametric analysis of variance (ANOVA) 

test that uses ranked data, was performed on physical and 

water-quality parameters to determine if there were statistical differences among the three continuously monitored sites. 

The level of significance for ANOVA was set at alpha equal 

to 0.05. If a significant difference was found, the Tukey’s 

multiple-comparison test was used to determine which groups 

differed significantly (Helsel and Hirsch, 1992). Specific conductance and pH values along with measured concentrations 

and instantaneous loads for SO4

, Ca, Al, Fe, Cd, Cu, and Zn 

were examined among sites by use of boxplots. A Spearman 

rho correlation test, which calculates a correlation coefficient 

based on the ranks of data, was used to determine the relation among concentrations of SO4, Ca, Al, Fe, Cd, Cu, and Zn. 

Spearman rho tests whether two constituent concentrations 

are independent of each other and ranges from values of -1 to 

+1. A value of -1 indicates that high ranks of one constituent 

are correlated to low ranks of the other constituent, whereas 

a value of +1 indicates that high ranks of one constituent are 

correlated to high ranks of the other constituent.

Standards outlined in the USEPA National Recommended Water Quality Criteria (NRWQC) and adopted by the 

State of Vermont were used to compare trace-element concentrations from this study to water-quality guidelines (U.S. Environmental Protection Agency, 2006). The Criteria Maximum 

Concentration (CMC) standards were used to assess acute 

toxicity to the aquatic community and are referred to in this 

report as acute toxicity standards. The Criterion Continuous 

Concentration (CCC) standards were used to assess chronic 

toxicity to the aquatic community and are referred to in this 

report as chronic toxicity standards. The acute and chronic 

toxicity standards for Cd, Cu, and Zn were adjusted based 

on hardness according to the NRWQC (U.S. Environmental 

Protection Agency, 2006).

The LOAD ESTimator (LOADEST) computer program 

(Runkel and others, 2004) was used to estimate loads of dissolved and total SO4

, Al, Fe, Cd, Cu, and Zn at sites 4 and 5. 

LOADEST is based on a regression equation in which time 

series of streamflow and constituent concentration are used 

as calibration data for the estimation of constituent loads. 

Explanatory variables within the regression model include 

various functions of streamflow and time (seasonality). 

Regression equations were developed for each constituent 

(SO4, Ca, Al, Fe, Cd, Cu, and Zn) at each site, models were fit 

using all possible combinations of these variables, and the best 

model was selected on the basis of the Akaike Information 

Criteria (Akaike, 1981). The specific method used for model 

calibration and load estimation is described by Runkel and 

others (2004).

The small drainage area of 0.11 mi2

 at site 1 precludes 

it from being modeled using LOADEST. Concentrations of 

chemical constituents, however, may be correlated to physical 

factors of surface waters such as streamflow, water temperature, specific conductance, and pH (Christensen and others, 

2000). Multiple regression analysis was used to evaluate 

variables that can affect concentrations of SO4

, Al, Fe, Cd, 

Cu, and Zn at site 1, and concentrations of Ca at sites 1, 4, 

and 5. A stepwise regression procedure was used to select 

variables that were significant in predicting concentrations of 

dissolved and total SO4

, Ca, Al, Fe, Cd, Cu, and Zn. A vari-

 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
able was considered significant if the difference between the 

mean and hypothesized standard error (t value) was greater 

than the absolute value of 2 (Helsel and Hirsch, 1992), and if 

the probability (p value) of the dependent variable was less 

than 0.01. The relation of significant variables with respect to 

concentrations was assessed graphically. If the graph showed 

curvature to the relationship, the log of the variable was used 

to transform it to a more linear relation. Multiple regression 

equations to estimate constituent concentrations were developed with the significant predictor variables for concentrations of SO4

, Ca, Al, Fe, Cd, Cu, and Zn. The strength of the 

regression equations was evaluated by use of the coefficient 

of determination (R2

) and the mean square error (MSE). The 

R2

 is a dimensionless measure of the fraction of the variance 

explained by regression and ranges from 0 to 1. The greater 

the explained variability is compared to the unexplained variability, the stronger the equation. The MSE is a measure of the 

variance between the measured and estimated concentrations 

and represents the portion of the data that is not explained 

by the regression equation. For the purposes of this study, a 

regression equation was acceptable if the R2

 was greater than 

0.75 and the MSE was less than 0.50.

The regression equations were applied to the continuous 

water-quality data to estimate instantaneous concentrations for 

SO4, Ca, Al, Fe, Cd, Cu, and Zn at site 1. Estimated daily mean 

concentrations and the recorded daily mean streamflow were 

used to estimate annual and seasonal loads of SO4, Ca, Al, Fe, 

Cd, Cu, and Zn (in kilograms per day) at site 1 and estimated 

annual and seasonal loads of Ca (in kilograms per day) at 

sites 4 and 5.

Surface-Water Hydrology

Based on 48 years of streamflow record (1958–2005) at 

the USGS streamflow-gaging station East Orange Branch at 

East Orange, VT (USGS station 01139800), local streamflow 

conditions during the study were normal. Normal streamflow 

is defined as annual mean streamflow that falls within the 25th

to 75th percentile streamflow-duration. Mean streamflow for 

water year 2005 at East Orange Branch at East Orange, VT 

was 15.1 ft3

/s, and was similar to the annual mean streamflow 

of 15.7 ft3

/s for the period of record (Kiah and others, 2005).

Base-flow conditions, where streamflow is sustained 

by ground-water discharge, were present in Pike Hill Brook 

for much of the fall of 2004. Streamflow increased during 

November and December 2004 as a result of seasonal rains 

and reduced evapotranspiration. Streamflow decreased to base 

flow for the remainder of the winter. Spring snowmelt and 

rains increased streamflow above normal during April and 

May 2005. Streamflow decreased seasonally to base flow, 

again, for the summer and fall of 2005. Seasonal rains in midto late-October and November 2005 resulted in streamflows 

above normal through December 2005.

Surface-Water Quality

Sites 1, 4, and 5 have small drainage areas and are 

subject to rapid changes in streamflow and water chemistry during periods of intense rainfall. Specific conductance 

generally increased with an increase in streamflow at site 1 

and decreased with an increase in streamflow at sites 4 and 5 

(fig. 2). During summer base flow at sites 1 and 5, however, 

there was an increase in specific conductance as streamflow 

decreased (fig. 2). pH generally decreased with an increase in 

streamflow at site 1 and remained stable or decreased slightly 

with an increase in streamflow at sites 4 and 5 (fig. 3). Minimum water temperatures were observed periodically during 

the winter; maximum temperatures were recorded in July 

2005. Summary statistics for the three continuously monitored 

sites on Pike Hill Brook are listed in table 2.

Specific Conductance and pH

The distribution of specific conductance and pH values 

in Pike Hill Brook with respect to distance from site 1 over 

a range in streamflows is shown in figure 4. The observed 

specific conductance and pH values at background sites and 

site 10 also are presented on this graph. Specific conductance 

values at background sites generally were lower than those 

observed at other synoptic sites (fig. 4A, table 3). The specific 

conductance in Pike Hill Brook decreased in a downstream 

direction from site 1 to site 5 and was similar among sites 5, 6, 

and 7 before the confluence with the Waits River. The specific 

conductance at site 10 was greater than values at background 

sites and similar to the specific conductance values at site 4. 

The specific conductance increased with increased streamflow 

at sites 1 and 3 and decreased when streamflow increased at 

site 2 and sites 4 through 10 (fig. 4A).

The pH values at background sites were greater than pH 

values at site 1 and were similar to pH values at sites 3, 4, 5, 6, 

7, 9, and 10 during low and normal streamflows (fig. 4B, 

table 3). The pH in Pike Hill Brook generally increased from 

site 1 to site 7. The pH generally was greater than 7 standard 

units at site 5. The pH at site 10 was 7.9 standard units for the 

three samples.

Specific conductance and pH values among the three 

continuously monitored sites were tested to determine if 

there were statistically significant differences in the data. 

Specific conductance and pH values were significantly 

different among the three continuously monitored sites 

(p<0.05) (fig. 5). Changes in specific conductance and 

pH values at sites 1, 4, and 5 are likely the result of rapid 

dilution from rain and inflows (ground- and surface water). 

Specific conductance and pH can be affected by a flushing 

of efflorescent sulfate salts, which form on waste sulfide 

materials (Alpers and others, 1992). Efflorescent sulfate salts 

were found during a geochemical characterization of the Pike 

Hill mine waste (Piatak and others, 2006a). During a typical 

rain event, there is an initial dilution of waters in Pike Hill 

Surface-Water Quality 
EXPLANATION

 Streamflow

 Specific conductance

100

10

1

0.1

0.01

2,500

1,500

1,000

500

0

2,000

DAILY MEAN SPECIFIC CONDUCTANCE, IN MICROSIEMENS PER CENTIMETER AT 25° CELSIUS

DAILY MEAN STREAMFLOW, IN CUBIC FEET PER SECOND

Site 4

100

10

1

0.1

0.01

400

200

100

0

300

Site 1

MONTH AND YEAR

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec

2004 2005

Site 5

100

10

1

0.1

0.01

400

200

100

0

300

Figure 2. The relation of daily mean streamflow to daily mean specific conductance at the three continuously monitored 

sites in the Pike Hill, VT, study area.

 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Figure 3. The relation of daily mean streamflow to daily mean pH at the three continuously monitored sites in the Pike 

Hill, VT, study area.

EXPLANATION

 Streamflow

 pH

100

10

1

0.1

0.01

8

6

3

2

7

DAILY MEAN pH, IN STANDARD UNITS

DAILY MEAN STREAMFLOW, IN CUBIC FEET PER SECOND

Site 4

100

10

1

0.1

0.01

8

Site 1

Site 5

100

10

1

0.1

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec

2004 2005

MONTH AND YEAR

5

4

6

3

2

7

5

4

8

6

3

2

7

5

4

Surface-Water Quality 
Table 2. Summary statistics of physical parameters from the three continuously monitored sites in the Pike Hill, VT, study area.

[ft3/s, cubic feet per second; μS/cm, microsiemens per centimeter at 25 degrees Celsius; oC, degrees Celsius; min, minimum; max, maximum. Refer to figure 1 and table 1 for site names, station numbers, and 

locations]

Site number

(table 1; 

fig. 1)

Streamflow

(ft3/s)

Specific conductance 

(μS/cm)

pH

(standard units)

Water temperature 

(°C)

Min Mean Median Max Min Mean Median Max Min Mean Median Max Min Mean Median Max

1

1 0.01 0.26 0.17 2.5 134 705 628 2,210 2.7 3.6 3.6 4.4 0.0 7.2 5.4 22.7

2

4 .06 1.75 .89 16.0 130 240 253 327 6.1 7.2 7.6 7.8 .0 10.6 13.2 20.6

1

5 .21 6.20 4.32 108 100 204 194 364 7.1 7.5 7.6 7.9 .0 7.8 4.7 26.9

1 Statistics based on data collected from November 2004 to December 2005.2 Statistics based on data collected from June 2005 to December 2005.

10 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
pH, IN STANDARD UNITS

SPECIFIC CONDUCTANCE, 

IN MICROSIEMENS PER CENTIMETER AT 25° CELSIUS

10,000

1,000

100

A

B

(1) (3) (4) (5) (6) (7) (9) (10) (2, 8)

EXPLANATION

 High flow

 Normal flow 

 Low flow

(9) Site number

9

6

3

(1) (3) (4) (5) (6) (7) (9) (10) (2, 8)

UNNAMED

TRIBUTARY

TO COOKVILLE

BROOK

BACKGROUND

SITES

0 1 2 3 4 5

DISTANCE DOWNSTREAM FROM SITE 1, IN MILES

0 1 2 3 4 5

8

7

5

4

Figure 4. Distribution of (A) specific conductance, and (B) pH at the synoptic monitoring sites in the Pike Hill, 

VT, study area.

Surface-Water Quality 11
Table 3. Summary statistics of physical parameters for synoptic sampling sites in the Pike Hill, VT, study area.

[ft3/s, cubic feet per second; μS/cm, microsiemens per centimeter at 25 degrees Celsius; oC, degrees Celsius; min, minimum; max, maximum. Refer to figure 1 and table 1 for site name, station number, and 

location]

Site 

number

(table 1; 

figure 1)

Streamflow

(ft3/s)

Specific conductance

(μS/cm)

pH

(standard units)

Water temperature

(oC)

Min Mean Median Max Min Mean Median Max Min Mean Median Max Min Mean Median Max

1 0.04 0.22 0.16 0.50 623 864 745 1,340 3.2 3.3 3.3 3.7 2.6 9.3 6.5 18.8

1

2 .01 .15 .03 .41 133 175 180 208 6.8 7.2 7.5 7.7 1.7 9.0 6.5 18.8

3 .14 .90 .55 2.4 247 298 302 341 6.0 6.5 7.0 7.4 1.8 9.4 6.7 19.8

4 .24 2.5 1.2 7.4 187 214 216 237 6.6 6.9 7.1 7.6 1.5 7.9 6.8 15.3

5 .92 9.3 4.0 28 143 200 210 236 7.2 7.4 7.5 7.8 1.0 7.6 7.0 14.8

6 1.1 10 4.6 31 144 199 206 240 7.3 7.5 7.5 7.7 1.2 9.8 7.2 21.0

7 1.2 10 4.6 31 139 202 214 238 7.3 7.7 8.0 8.3 1.0 9.6 6.9 21.0

1

8 27 118 89 238 143 184 189 217 7.2 7.6 8.0 8.4 1.7 7.5 5.6 15.3

1

9 31 138 111 271 145 193 202 223 7.7 8.0 8.0 8.5 1.8 8.1 6.5 15.9

210 .19 .41 .41 .63 214 226 214 251 7.9 7.9 7.9 7.9 7.1 13.5 14.9 18.6 

1 Streamflow statistics based on three observations.2 Streamflow statistics based on two observations; specific conductance, pH, and water temperature statistics based on three observations.

12 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
A

 SPECIFIC CONDUCTANCE, IN MICROSIEMENS PER CENTIMETER AT 25oCELSIUS

EXPLANATION

Number of samples

 Site 1—401

 Site 4—165

 Site 5—406

Multiple comparison group - A

Outlier

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

Outlier

100

1,000

10,000

A

B C

B

Site 1 Site 4 Site 5

pH, IN STANDARD UNITS

A

B C

3

4

5

6

7

8

SAMPLING SITE

Figure 5. A comparison of daily mean (A) specific conductance, and (B) pH 

among the three continuously monitored sites in the Pike Hill, VT, study area.

Surface-Water Quality 13
Brook at site 1, which results in an initial decrease in specific 

conductance and an increase in pH (fig. 6). Overland flow and 

rapid infiltration through the waste rocks and tailings piles 

may dissolve and flush the highly soluble efflorescent sulfate 

salts, resulting in an increase in specific conductance and a 

decrease in pH (fig. 6).

Pike Hill Brook mixes with waters from tributaries as it 

flows downstream to site 4. Specific conductance decreases 

and pH increases with the dilution of constituents from 

an increase in streamflow in Pike Hill Brook (fig. 6). The 

mixing of ARD with waters of high pH may also cause the 

precipitation of Al and Fe hydroxides and sorption of trace 

metals (Lee, 2001). This may result in an initial decrease 

in specific conductance and an increase in pH. During the 

streamflow recession, the specific conductance increases to 

values greater than those measured prior to the event and pH 

decreases (fig. 6). Increases in specific conductance are likely 

the result of the associated increases in sulfate related to the 

acid generated by sulfide oxidation. Decreases in pH may 

result from a breakdown of the bicarbonate buffering system 

downstream of ARD as waters with more total acidity flow 

downstream following rain events, lessening the capacity of 

the water to buffer changes in pH (Kelly, 1988). Furthermore, 

oxidation of ferrous iron consumes acid, and hydrolysis of 

the ferric iron produces acid. Although hydrolysis of ferric 

iron at a pH greater than or equal to 7 standard units can take 

only minutes, the process may require hours as pH levels drop 

below 7 standard units (Haddad and Jenkins, 1984).

As streamflow increases at site 5 during rain events, the 

specific conductance decreases and the pH remains stable 

or slightly decreases (fig. 6). Over the streamflow recession 

following a rainfall event, the specific conductance and pH 

increase to levels similar to those observed prior to the event, 

suggesting that there is no or limited breakdown of the carbonate buffering system during rainfall events (fig. 6).

Major Ions and Trace Elements

Acute and chronic toxicity standards used in this report 

and the percentage of samples found exceeding the standards 

at eight sites and two background sites (sites 2 and 8) are 

listed in table 4. The acute and chronic toxicity standards 

for Cd, Cu, and Zn were calculated using a median hardness 

value from the 10 water-quality sampling sites of 98 mg/L 

(as CaCO3

). Concentrations of Al, Fe, Cd, Cu, and Zn were 

above acute and chronic toxicity standards at some sites, 

whereas no concentrations of Al, Fe, Cd, Cu, and Zn were 

above acute and chronic toxicity standards at background sites 

(table 4). Summary statistics for water-quality concentrations 

and instantaneous loading data are listed in tables 5 and 6, 

respectively. Concentrations of Al, Fe, Cd, Cu, and Zn in the 

stream sediments also are listed in table 5 (Piatak and others, 

2006b).

Median concentrations and mean instantaneous loads 

are presented in the following sections. Median concentrations are presented to characterize typical concentrations and 

the repeated daily exposure to trace elements that may be 

observed at each site. Mean instantaneous loads are presented to characterize the average quantity of a trace element 

observed at each site and to describe the fate and transport of 

trace elements between sites.

A daily mean streamflow hydrograph for the datacollection period, the dates and instantaneous streamflow 

for the water-quality samples, and the distribution of water 

samples with respect to time for the three continuously 

monitored sites are shown in figures 7, 8, and 9. The 

variability in streamflow chemistry was represented by the 

collection of 24 water samples at site 1 (fig. 7A), 9 water 

samples at site 4 (fig. 8A), and 19 water samples at site 5 

(fig. 9A). Because the instantaneous streamflow is used to 

represent the water samples, occasionally these data points do 

not fall on the line representing the daily mean streamflow. A 

cumulative frequency-duration curve showing the percentage 

of time that a given daily mean streamflow is expected to be 

equaled or exceeded, the streamflow at which water samples 

were collected, and the distribution of water samples across 

the various streamflows observed at sites 1, 4, and 5 are shown 

in figures 7B, 8B, and 9B, respectively. Ninety percent of 

the streamflows expected at sites 1 and 5 were represented 

by a water sample and represent the range in flow duration, 

except for extreme low streamflows (streamflows greater than 

90th percentile flow duration) (figs. 7B and 9B). Eighty 

percent of the streamflows expected at site 4 were represented 

by a water sample and represent the range in flow duration, 

except for extreme low streamflows (streamflows greater than 

80th percentile flow duration) (fig. 8B).

Sulfate and Calcium

SO4 is derived from the oxidation of sulfide minerals and 

may be used to indicate the presence of ARD. Ca is derived 

from the weathering of carbonate minerals and can indicate 

additions of alkalinity and hardness to local surface waters.

The spatial distributions of median concentrations and 

mean instantaneous loads for SO4

 and Ca are shown in 

figures 10 and 11, respectively. Median concentrations of 

SO4

 and Ca at sites in Pike Hill Brook generally decreased 

with distance downstream from site 1, 3, and 4, and were 

similar at sites 5, 6, and 7 (figs. 10A and 11A, table 5). 

SO4

 concentrations at sites in Pike Hill Brook and site 

10 were greater than concentrations at background sites. 

Ca concentrations at sites 1, 3, and 10 were greater than 

concentrations at background sites, whereas concentrations 

at sites 4, 5, 6, and 7 were similar to concentrations at 

background sites (table 5). The median concentrations of 

SO4 and Ca at sites in the Waits River above and below the 

confluence with Pike Hill Brook (sites 8 and 9, respectively) 

were similar (table 5).

14 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Figure 6. The typical response of instantaneous specific conductance and pH to streamflow events at the three 

continuously monitored sites in the Pike Hill, VT, study area.

EXPLANATION

 Streamflow

 Specific conductance

 pHINSTANTANEOUS SPECIFIC CONDUCTANCE, IN MICROSIEMENS PER CENTIMETER AT 25° CELSIUS

INSTANTANEOUS STREAMFLOW, IN CUBIC FEET PER SECOND

INSTANTANEOUS pH, IN STANDARD UNITS

DAY AND MONTHINSTANTANEOUS STREAMFLOW, IN CUBIC FEET PER SECOND

Site 1

0

 400

800

1,200

1,600

2,000

0

0.2

0.4

0.6

0.8

1.0

Site 1

3.0

3.2

3.4

3.6

3.8

4.0

0

0.2

0.4

0.6

0.8

1.0

Site 4

140

180

220

260

300

340

0

4

8

12

16

20

Site 4

6.0

6.4

6.8

7.2

7.6

8.0

0

4

8

12

16

20

Site 5

140

180

220

260

300

340

0

10

20

30

40

50

15 16 17 18 19 20

October 2005

Site 5

0

10

20

30

40

50

15 16 17 18 19 20

October 2005

6.0

6.4

6.8

7.2

7.6

8.0

Surface-Water Quality 15
Table 4. Summary of the U.S. Environmental Protection Agency National Recommended Water Quality Criteria for priority and 

non-priority pollutants and the percentage of exceedance at the Pike Hill, VT, study area. 

[μg/L, micrograms per liter; acute standard, Criteria Maximum Concentration; chronic standard, Criteria Continuous Concentration. Refer to table 1 and 

figure 1 for site names, station numbers, and locations]

Pollutants

Acute 

standard

(μg/L)

Percentage of samples exceeding acute toxicity standards 

Site 1 Site 3 Site 4 Site 5 Site 6 Site 7 Site 9 Site 10 Background1

Priority pollutant

Cadmium2 2.0 100 50 44 0 0 0 0 0 0

Copper2 13 100 100 78 32 25 25 0 0 0

Zinc2 120 100 100 56 0 0 0 0 0 0

Non-priority pollutant

Aluminum3 750 100 0 0 0 0 0 0 0 0

Pollutants

Chronic 

standard

(μg/L)

Percentage of samples exceeding chronic toxicity standards

Site 1 Site 3 Site 4 Site 5 Site 6 Site 7 Site 9 Site 10 Background1

Priority pollutant

Cadmium2 0.24 100 100 100 26 25 25 0 0 0

Copper2 8.8 100 100 89 58 50 50 0 33 0

Zinc2 120 100 100 56 0 0 0 0 0 0

Non-priority pollutant

Aluminum3 87 100 0 0 0 0 0 0 0 0

Iron 1,000 100 25 11 0 0 0 0 0 0

1 Sites 2 and 8 (refer to table 1).

2 Acute and chronic toxicity standards adjusted for hardness of 98 milligrams per liter (mg/L).

3 Acute and chronic toxicity standards for waters with pH 6.5–9.0 and for total recoverable concentrations.

16  Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Table 5. Summary statistics for concentrations of sulfate, calcium, aluminum, iron, cadmium, copper, and zinc in water samples and a stream-sediment sample collected at sites 

in the Pike Hill, VT, study area.

[QW, water quality; mg/L, milligrams per liter; μg/L, micrograms per liter; min, minimum; max, maximum; <, less than; --, not calculated; %, percent; mg/kg, milligrams per kilogram. Refer to figure 1 and table 1 for site name, station number, and location]

Site 

number

(table 1; 

figure 1)

Number 

of QW 

samples

Dissolved concentration

Sulfate

(mg/L)

Calcium

(mg/L)

Aluminum (Al)

(μg/L)

Iron (Fe)

(μg/L)

Min Mean Median Max Min Mean Median Max Min Mean Median Max Min Mean Median Max

1 24 242 373 324 691 54.1 64.7 62.2 96.8 5,680 8,630 7,860 15,200 8,440 37,500 25,000 150,000

2 4 7.6 8.1 8.0 8.9 21.9 32.8 34.3 40.9 2 3 2 4 <50 -- <50 <50

3 4 95.0 118 106 162 36.7 44.8 45.0 52.6 10 14 14 20 <50 -- <50 18,700

4 9 31.7 56.8 51.0 97.0 26.1 36.8 37.4 45.1 <2 -- 8 22 <50 -- -- 2,680

5 19 7.1 16.2 14.1 32.2 14.7 27.8 29.5 39.8 2 9 8 18 <50 -- -- 230

6 4 5.7 12.6 14.3 16.3 20.3 31.0 32.3 39.0 4 7 6 12 70 120 120 160

7 4 6.7 12.5 13.6 16.1 19.1 30.5 31.8 39.4 3 7 7 13 <50 -- -- 110

8 4 6.0 6.8 6.5 8.0 21.9 31.5 32.3 39.5 5 11 12 16 <50 -- <50 <50

9 4 6.9 10.4 8.2 18.1 22.3 32.0 33.8 37.9 6 11 11 17 <50 -- <50 240

10 3 11.6 14.2 15.0 16.0 41.6 46.8 45.1 53.8 15 36 30 64 <50 -- <50 <50

Site 

number

Number 

of QW 

samples

Dissolved concentration Stream sediment concentration1

Cadmium (Cd)

(μg/L)

Copper (Cu)

(μg/L)

Zinc (Zn)

(μg/L) Al Fe Cd Cu Zn 

Min Mean Median Max Min Mean Median Max Min Mean Median Max (%) (%) (mg/kg) (mg/kg) (mg/kg)

1 24 8.11 25.6 18.8 92.8 1,940 6,900 3,720 30,800 1,870 3,230 2,670 7,340 3.03 21.5 5.8 8,070 1,070

2 4 <0.02 -- <0.02 <0.02 0.5 0.8 0.7 1.5 <0.5 -- 1 2 5.76 3.36 0.5 262 134

3 4 1.61 6.40 2.54 18.9 24.0 848 38.0 3,290 247 674 380 1,690 5.08 7.64 3.2 3,530 675

4 9 .45 2.29 1.05 5.84 7.9 85.5 25.5 299 42 295 124 631 4.96 6.67 4.8 3,540 834

5 19 .08 .19 .16 .49 3.9 12.2 9.6 37.1 9 27 22 65 5.36 2.72 1.6 298 283

6 4 .09 .18 .15 .32 4.9 14.0 9.6 33.0 10 21 14 46 4.62 1.84 .9 119 191

7 4 .04 .12 .07 .28 4.3 13.0 8.0 30.0 5 16 9 40 4.29 1.4 1.4 98.1 224

8 4 <.02 -- <.02 <.02 <.5 -- <.5 0.5 <.5 -- -- 3 3.8 2.04 .1 7.7 44

9 4 <.02 -- <.02 .02 .6 1.1 1.1 1.7 1 2 2 4 4.06 1.35 .1 8.0 43

10 3 .10 .13 .11 .18 3.6 6.3 4.0 11.0 13 18 15 25 4.74 2.43 1.5 539 685

1 From Piatak and others, 2006b.

Surface-Water Quality 17
Table 6. Summary statistics of instantaneous loads of sulfate, calcium, aluminum, iron, cadmium, copper, and zinc in water samples collected at sites in the Pike Hill, VT, 

study area. 

[min, minimum; max, maximum; <, less than. Refer to figure 1 and table 1 for site name, station number, and location]

Site 

number 

(table 1; 

figure 1)

Number of 

samples

Instantaneous load, in kilograms per day

Sulfate Calcium Aluminum Iron

Min Mean Median Max Min Mean Median Max Min Mean Median Max Min Mean Median Max

1 24 33.5 415 209 1,540 6.9 64.4 42.6 217 0.59 9.81 5.49 31.3 1.02 52.5 21.4 333

2 4 0.2 2.8 0.6 7.7 0.8 8.5 2.7 22.0 <.01 <0.01 <0.01 <0.01 <0.01 0.01 <0.01 0.02

3 4 33.0 313 144 932 15.0 89.0 64.0 211 <.01 .03 .02 .06 .01 27.0 .03 108

4 9 26.9 325 137 935 24.3 174 89.2 469 .01 .03 .02 .06 .01 6.72 .05 48.2

5 19 18.0 411 271 1,570 89.6 682 464 2,560 .02 .42 .11 3.14 .06 1.60 .82 9.42

6 4 15.0 384 156 1,210 105 594 369 1,530 .01 .27 .08 .93 .29 3.05 1.08 9.75

7 4 20.0 366 152 1,140 116 569 358 1,440 .02 .28 .07 .97 .07 2.39 .51 8.47

8 3 525 1,800 1,370 3,490 2,220 7,230 6,710 12,760 .31 3.27 2.75 6.76 1.64 7.22 5.45 15.0

9 3 714 4,860 1,870 12,000 2,720 8,680 8,530 14,790 .44 3.62 3.26 7.16 1.88 28.0 17.0 66.0

10 2 7.4 15.0 15.0 23.0 21.0 43.0 43.0 64.0 .01 .05 .05 .10 .01 .02 .02 .04

Site 

number

Number of 

samples

Instantaneous load, in kilograms per day

Cadmium Copper Zinc

Min Mean Median Max Min Mean Median Max Min Mean Median Max

1 24 0.001 0.035 0.014 0.182 0.19 10.5 2.38 68.4 0.22 3.84 1.78 15.4

2 4 <.001 <.001 <.001 <.001 <.01 <0.01 <0.01 <0.01 <.01 <0.01 <0.01 <0.01

3 4 .001 .029 .004 .109 .01 4.76 .06 19.0 .08 2.72 .54 9.72

4 9 <.001 .022 .004 .105 .01 1.10 .05 5.32 .05 2.58 .49 9.755 19 <.001 .006 .002 .032 .02 .49 .16 2.46 .02 .85 .46 4.28

6 4 <.001 .007 .002 .024 .02 .67 .11 2.46 .03 .95 .17 3.45

7 4 <.001 .006 .001 .021 .02 .62 .09 2.27 .01 .81 .11 3.018 3 <.001 .003 .002 .006 .02 .07 .05 .15 .02 .15 .13 .299 3 <.001 .006 .005 .013 .04 .51 .35 1.13 .08 1.12 .90 2.39

10 2 <.001 <.001 <.001 <.001 <.01 .01 .01 .02 .01 .02 .02 .04

18  Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
A

B

DAILY MEAN STREAMFLOW, IN CUBIC FEET PER SECOND

0

0.2

0.4

0.6

0.8

1.2

1.4

1.6

1.0

Oct 1 Jan 1 Apr 1 Jul 1 Oct 1 Jan 1

2004 2005

MONTH AND YEAR

Daily mean streamflow

Water-quality sample

 Flow-duration curve

 Water-quality sample

0.01

0.1

1

10

0.01 .1 1 5 10 20 30 50 70 80 90 95 99 99.9 99.99 2

PROBABILITY OF EXCEEDENCE, IN PERCENT

Site 1, station 01139830

Figure 7. (A) Daily mean streamflow and time distribution of water-quality samples, and (B) flow-duration curve with 

streamflow distribution of water-quality samples for Pike Hill Brook above Richardson Road near Bradford, VT, station 

01139830, site 1.

Surface-Water Quality 19
Figure 8. (A) Daily mean streamflow and time distribution of water-quality samples, and (B) flow-duration curve with 

streamflow distribution of water-quality samples for Pike Hill Brook at Pike Hill Road, west crossing, near Bradford, VT, 

station 01139833, site 4.

A

B

DAILY MEAN STREAMFLOW, IN CUBIC FEET PER SECOND

0

2

4

6

8

10

Oct 1 Jan 1 Apr 1 Jul 1 Oct 1 Jan 1

2004 2005

MONTH AND YEAR

 Daily mean streamflow

 Water-quality sample

0.1

1

10

0.01 .1 1 5 10 20 30 50 70 80 90 95 99 99.9 99.99 2

PROBABILITY OF EXCEEDENCE, IN PERCENT

Site 4, station 01139833

 Flow-duration curve

 Water-quality sample

20 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Figure 9. (A) Daily mean streamflow and time distribution of water-quality samples, and (B) flow-duration curve with 

streamflow distribution of water-quality samples for Pike Hill Brook at Pike Hill Road near Bradford, VT, station 01139838, 

site 5.

A

B

DAILY MEAN STREAMFLOW, IN CUBIC FEET PER SECOND

0

10

20

30

40

60

70

80

50

Oct 1 Jan 1 Apr 1 Jul 1 Oct 1 Jan 1

2004 2005

MONTH AND YEAR

 Daily mean streamflow

 Water-quality sample

 Flow-duration curve

 Water-quality sample

0.1

1

10

100

0.01 .1 1 5 10 20 30 50 70 80 90 95 99 99.9 99.99 2

PROBABILITY OF EXCEEDENCE, IN PERCENT

Site 5, station 01139838

Surface-Water Quality 21
Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

0 0.5 1 MILE

0 0.5 1 KILOMETER

Base from U.S. Geological Survey

West Topsham, 1981, 1:24,000 and

East Corinth, 1973, 1:24,000

Vermont State Plane Coordinate System

44°05'

A

Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

44°05'

B

EXPLANATION 

 Sampling site with identification

 Greater than 75th percentile

 50th to 75th percentile

 25th to less than 50th percentile

 Less than 25th percentile

 Mine

Sulfate

2

Figure 10. (A) Median concentrations of sulfate, and (B) mean instantaneous loads of sulfate in relation to 

percentiles of the data at synoptic sampling sites in the Pike Hill, VT, study area.

22 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

0 0.5 1 MILE

0 0.5 1 KILOMETER

Base from U.S. Geological Survey

West Topsham, 1981, 1:24,000 and

East Corinth, 1973, 1:24,000

Vermont State Plane Coordinate System

44°05'

A

Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

44°05'

B

EXPLANATION 

 Sampling site with identification

 Greater than 75th percentile

 50th to 75th percentile

 25th to less than 50th percentile

 Less than 25th percentile

 Mine

Calcium

2

Figure 11. (A) Median concentrations of calcium, and (B) mean instantaneous loads of calcium in relation 

to percentiles of the data at synoptic sampling sites in the Pike Hill, VT, study area.

Surface-Water Quality 23
Instantaneous SO4

 loads at sites in Pike Hill Brook 

were similar with distance downstream from site 1 (fig. 10B, 

table 6), whereas instantaneous Ca loads at sites in Pike Hill 

Brook generally increased with distance downstream from 

site 1 (fig. 11B, table 6). The mean instantaneous load of SO4

at site 10 generally was less than those at sites in Pike Hill 

Brook, whereas the mean instantaneous Ca load at site 10 was 

similar to those at sites 1 and 3 and less than at sites 4, 5, 6, 

and 7 (fig. 10B, table 6). The mean instantaneous SO4

 and Ca 

loads at site 9 were greater than those at site 8 (table 6).

A statistical analysis of SO4

 and Ca concentrations 

among the three continuously monitored sites showed 

significant differences in the data (p<0.05) (fig. 12A and 

12C). Mean instantaneous loads of SO4

, however, decreased 

from site 1 (415 kg/d) to site 4 (325 kg/d) and increased from 

site 4 to site 5 (411 kg/d) (table 6) but were not significantly 

different among the three sites (p>0.05) (fig. 12B). This 

similarity indicated that dilution was affecting the change 

in concentrations of SO4

 in Pike Hill Brook. Instantaneous 

loads of Ca were significantly different among the three sites 

(p<0.05) (fig. 12D). The considerable increase in Ca loads 

between sites, in a downstream direction (table 6), probably 

resulted from an influx of Ca with the increase in streamflow.

Aluminum and Iron

Al and Fe are considered non-priority pollutants by the 

USEPA. Al and Fe sorb to particulates and precipitate out of 

the water column as Al and Fe hydroxides, as the pH of ARD 

increases. The critical pH for Al precipitation is about 5.2 

standard units, whereas the critical pH for Fe precipitation is 

about 4.3 standard units (Kelly, 1988).

Concentrations of Al and Fe for 24 water-quality 

samples (100 percent) at site 1 were greater than the NRWQC 

standards for acute and chronic toxicity (table 4). The 

NRWQC standards for Al are based on the total concentration 

and on a pH range of 6.5 to 9.0, which is a higher pH range 

than that observed at site 1. Chronic toxicity standards were 

exceeded in one high streamflow sample for Fe at sites 3 and 

4 (table 4). No sample concentrations of Al or Fe exceeded 

toxicity standards at background sites or sites 5, 6, 7, 9, and 

10. Sample concentrations of Al and Fe at background sites 

generally were lower than those observed at other synoptic 

sites (table 5).

The spatial distribution of median concentrations and 

mean instantaneous loads for Al is shown in figure 13. The 

median concentration of Al at each site is shown relative to the 

NRWQC. The mean instantaneous loads at each site are shown 

in relation to percentiles of the observed loads for all synoptic 

samples. Percentiles, in this usage, are the percentage of the 

observed constituent loads that were equal to or smaller than 

the mean constituent load at each site.

Concentrations of Al and Fe differed in magnitude but 

were positively correlated (rho = 0.92, p<0.0001) and showed 

similar patterns in relation to streamflow. Concentrations of 

Al and Fe varied considerably among sites in Pike Hill Brook 

(table 5). Median concentrations of Al and Fe were greatest at 

site 1 and generally decreased with distance downstream from 

site 1. Median Fe concentrations, however, were greater at 

sites below the wetlands (sites 5, 6, and 7) than at sites 3 and 

4 (table 5). Median Al concentrations at site 10 were greater 

than those in Pike Hill Brook downstream from site 1 

(table 5). Concentrations of Fe at site 10 were below the 

detection limit of 50 μg/L for all streamflows sampled. 

Median Al concentrations at sites in the Waits River (sites 8 

and 9) were similar to those in Pike Hill Brook downstream 

from site 1 (table 5).

The mean instantaneous Al and Fe loads generally decreased with distance between site 1 and site 4 and 

increased with distance between site 4 and site 6. Instantaneous Al loads increased in Pike Hill Brook downstream 

from site 4 during high flow, whereas instantaneous Fe loads 

increased in Pike Hill Brook downstream from site 4 during normal and low flows. The mean instantaneous Al loads 

at site 10 were similar to those at site 3 in Pike Hill Brook 

(table 6). The mean instantaneous Al and Fe loads in the Waits 

River below the confluence with Pike Hill Brook (site 9) were 

greater than those above the confluence with Pike Hill Brook 

(site 8) (table 6).

Concentrations and instantaneous loads of Al and Fe 

among the three continuously monitored sites were tested to 

determine if there were statistically significant differences 

in the data. Concentrations of Al and Fe were significantly 

greater at site 1 than at sites 4 and 5 (p<0.05) but were not 

significantly different between sites 4 and 5 (p>0.05) 

(figs. 14A and 14C, table 5). Concentrations of Fe, however, 

ranged from less than 50 to 2,680 μg/L at site 4 and ranged 

from less than 50 to 230 μg/L at site 5 (table 5). Instantaneous 

loads of Al were significantly different among the three 

continuously monitored sites (p<0.05) (fig. 14B) as mean 

instantaneous loads of Al decreased from site 1 (9.81 kg/d) 

to site 4 (0.03 kg/d) and increased from site 4 to site 5 

(0.42 kg/d) (table 6). Instantaneous loads of Fe were significantly different between sites 1 and 4 and between sites 1 and 

5 (p<0.05) but did not differ between sites 4 and 5 (p>0.05) 

(fig. 14D).

Concentrations of Al and Fe decreased with distance 

from site 1 as the result of dilution and through sorption and 

precipitation of the trace elements. These constituents were 

sorbed and precipitated as ARD became diluted with waters 

of high pH between sites 1 and 4. This dilution resulted in the 

sorption of trace elements to hydroxides formed from Al and 

Fe (Kelly, 1988). Instantaneous loads for dissolved Al and Fe 

decreased by 1 to 3 orders of magnitude between sites 1 and 

4, most likely the result of sorption and precipitation with an 

increase in pH. Instantaneous Al loads increased between 

sites 4 and 5 during high streamflows, whereas instantaneous 

Fe loads increased between sites 4 and 5 during low and normal streamflows. The increase in Al loads probably resulted 

from an influx of Al from tributaries entering Pike Hill Brook. 

The increased Fe loads probably resulted from the dissolution 

of Fe hydroxides in the anaerobic areas of the wetlands. 

24 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
EXPLANATION

Number of samples

 Site 1—24

 Site 4—9

 Site 5—19

Multiple comparison group - A

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

CONCENTRATION, IN MILLIGRAMS PER LITER

A

1

100

1,000

A

B

C

10

SULFATE

INSTANTANEOUS LOAD, IN KILOGRAMS PER DAY

B

10

1,000

10,000

A A

A

100

SULFATE

C

Site 1 Site 4 Site 5

100

A

B

C

SAMPLING SITE

10

CALCIUM

D

Site 1 Site 4 Site 5

10

1,000

10,000

A

B

C

100

CALCIUM

SAMPLING SITE

Figure 12. A comparison of (A) concentrations of sulfate, (B) instantaneous loads of sulfate, (C) concentrations of calcium, and 

(D) instantaneous loads of calcium among the three continuously monitored sites in the Pike Hill, VT, study area.

Surface-Water Quality 25
Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

0 0.5 1 MILE

0 0.5 1 KILOMETER

Base from U.S. Geological Survey

West Topsham, 1981, 1:24,000 and

East Corinth, 1973, 1:24,000

Vermont State Plane Coordinate System

44°05'

A

Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

44°05'

B

EXPLANATION 

 Sampling site with

 identification

 Greater than 75th 

 percentile

 50th to 75th 

 percentile

 25th to less than 50th

 percentile

 Less than 25th 

 percentile

 Mine

Aluminum

EXPLANATION 

Sampling site 

 with identification

Greater than acute 

 toxicity standard

 Less than chronic 

 toxicity standard

 Mine

2

2

Figure 13. (A) Median concentrations of aluminum in relation to U.S. Environmental Protection Agency National Recommended 

Water Quality Criteria, and (B) mean instantaneous loads of aluminum in relation to percentiles of the data at synoptic sampling sites in 

the Pike Hill, VT, study area.

26  Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Figure 14. A comparison of (A) concentrations of aluminum, (B) instantaneous loads of aluminum, (C) concentrations of iron, and 

(D) instantaneous loads of iron among the three continuously monitored sites in the Pike Hill, VT, study area.

EXPLANATION

Number of samples

 Site 1—24

 Site 4—9

 Site 5—19

Multiple comparison group - A

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

CONCENTRATION, IN MICROGRAMS PER LITER

A

1

100

100,000

A

B B 10

ALUMINUM

INSTANTANEOUS LOAD, IN KILOGRAMS PER DAY

B

A

B

C

Site 1 Site 4 Site 5

A

B

B

SAMPLING SITE

10

IRON

D

Site 1 Site 4 Site 5

0.01

100

1,000

A

B

B

100

IRON

SAMPLING SITE

10,000

1,000

Detection limit

ALUMINUM

0.001

0.1

100

0.01

10

1

100

100,000

10,000

1,000

0.1

10

C

Detection limit

Surface-Water Quality 27
Kelly (1988) showed that the deep mixing of oxygen in water 

bodies caused adsorption of trace elements to the sediments. 

These trace elements may be desorbed during periods of 

anaerobic activity, which was expected during low streamflows.

Cadmium, Copper, and Zinc

Cd, Cu, and Zn are toxic to aquatic life and are considered priority pollutants by the USEPA. Cd, Cu, and Zn are 

removed from waters by precipitation and sorption, especially 

with hydroxides formed from Al and Fe (Kelly, 1988), can 

then settle out of the water column, or be transported downstream depending upon water velocity.

Concentrations of Cd, Cu, and Zn for all water samples 

at site 1 were greater than the NRWQC standards for acute 

and chronic toxicity (table 4). Concentrations of Cd exceeded 

acute toxicity criteria at sites 1, 3, and 4 during high flow, 

at sites 1 and 3 during normal flow, and at site 1 during 

low flow. Concentrations of Cd exceeded chronic toxicity 

criteria at all sites on Pike Hill Brook during high flow and at 

sites 1, 3, and 4 during normal and low flows. Concentrations 

of Cu exceeded acute toxicity criteria at all sites on Pike Hill 

Brook during high flow, at sites 1, 3, 4, and 5 during normal 

flow, and at sites 1 and 3 during low flow. Concentrations of 

Cu exceeded chronic toxicity criteria at all sites on Pike Hill 

Brook during high and normal flows, at site 10 during normal 

flows, and at sites 1, 3, and 4 during low flows. Concentrations 

of Zn exceeded acute and chronic toxicity criteria at sites 1, 3, 

and 4 during high flow conditions and at sites 1 and 3 during 

normal and low flow conditions. No concentrations of Cd, Cu, 

or Zn exceeded toxicity standards at background sites or site 9.

The spatial distribution of median concentrations and 

mean instantaneous loads for Cd and Cu is shown in figures 15 

and 16. The median concentrations of Cd and Cu at each site 

are shown relative to the NRWQC. The mean instantaneous 

loads at each site are shown in relation to percentiles of the 

observed loads for all synoptic samples. Percentiles, in this 

usage, are the percentage of the observed constituent loads 

that were equal to or smaller than the mean constituent load at 

each site.

Concentrations of Cd and Zn differed in magnitude but 

were positively correlated (rho = 0.99, p<0.0001) and showed 

similar patterns in relation to streamflow. Cd, Cu, and Zn concentrations and instantaneous loads at sites in Pike Hill Brook 

(sites 1, 3, 4, 5, 6, and 7) generally decreased with distance 

downstream from site 1 (table 5). The median Cd and Zn concentrations at site 10 were similar to those in Pike Hill Brook 

at sites 5, 6, and 7, whereas the median Cu concentration at 

site 10 was less than those at sites in Pike Hill Brook (table 5). 

Concentrations of Cd in the Waits River (sites 8 and 9) were 

equal to or below the detection limit of 0.2 μg/L for all streamflows sampled (table 5). The median Cu and Zn concentrations 

in the Waits River below the confluence with Pike Hill Brook 

(site 9) were greater than those above the confluence with 

Pike Hill Brook (site 8) (table 5).

Mean instantaneous loads of Cd, Cu, and Zn at sites in 

Pike Hill Brook (sites 1, 3, 4, 5, 6, and 7) generally decreased 

with distance downstream from site 1 (figs. 15B and 16B, 

table 6). Median Cu loads in Pike Hill Brook, however, 

increased with distance from site 4 to site 5 (table 6). Instantaneous Cd, Cu, and Zn loads at site 10 were lower than 

those observed at sites in Pike Hill Brook for all streamflows 

sampled (table 6). Mean instantaneous Cd, Cu, and Zn loads 

in the Waits River below the confluence with Pike Hill Brook 

(site 9) were greater than those above the confluence with 

Pike Hill Brook (site 8) (table 6).

A statistical analysis of concentrations of Cd, Cu, and 

Zn among the three continuously monitored sites showed 

significant differences among the three sites (p<0.05) (fig. 17). 

Instantaneous loads of Cd and Zn, however, were significantly 

different between sites 1 and 5 (p<0.05) but not significantly 

different between sites 1 and 4 or between sites 4 and 5 

(p>0.05) (fig. 17). Instantaneous loads of Cu were significantly different between sites 1 and 4 and between sites 1 and 

5 (p<0.05) but did not differ between sites 4 and 5 (p>0.05) 

(fig. 17).

Concentrations of Cd, Cu, and Zn decreased with distance 

from site 1 as the result of dilution and through sorption and 

precipitation of the trace elements. These constituents were 

sorbed and precipitated as ARD became diluted with waters of 

high pH between sites 1 and 4. Sorbed trace elements settled 

out of the water column or were transported downstream as 

the result of a decrease in water velocity between sites 4 and 

5. Instantaneous loads for dissolved Cu decreased by two 

orders of magnitude between sites 1 and 4, most likely the 

result of sorption and precipitation with an increase in pH. 

Instantaneous loads of Cd and Zn, however, were similar 

between sites 1 and 4. This similarity indicated that dilution is 

affecting the change in concentrations of Cd and Zn between 

sites 1 and 4 and that Cu was sorbed to Al and Fe hydroxides. 

Similarly to instantaneous loads of Fe, instantaneous loads 

of Cu increased between sites 4 and 5 during low and normal 

streamflows, probably resulting from the dissolution of Fe 

hydroxides in anaerobic areas of the wetlands.

Effects of Spring Rains and Snowmelt on 

Constituent Concentrations and Loads

Samples collected at sites 1 and 5 in late March and 

early- to mid-April were used to describe the effects of spring 

rains and snowmelt on constituent concentrations and loads. 

The distribution of Cu and Zn concentrations over time at 

sites 1 and 5 is shown in figure 18. Although the magnitude of 

concentrations was different, the changes in Cu concentration 

relative to changes in streamflow were similar to those of SO4

and Fe concentrations, whereas changes in Zn concentrations 

relative to changes in streamflow were similar to those of Al 

and Cd concentrations. Therefore, concentrations of Cu and 

Zn were used to describe the patterns for the constituents 

during spring rains and snowmelt in the following sections. 

28   Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

0 0.5 1 MILE

0 0.5 1 KILOMETER

Base from U.S. Geological Survey

West Topsham, 1981, 1:24,000 and

East Corinth, 1973, 1:24,000

Vermont State Plane Coordinate System

44°05'

A

Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

44°05'

B

EXPLANATION 

 Sampling site with

 identification

 Greater than 75th 

 percentile

 50th to 75th 

 percentile

 Less than 25th 

 percentile

 Mine

Cadmium

EXPLANATION 

 Sampling site 

 with identification

Greater than acute 

 toxicity standard

Greater than chronic

 and less than acute 

 standards

 Less than chronic 

 toxicity standard

 Mine

2

2

Figure 15. (A) Median concentrations of cadmium in relation to U.S. Environmental Protection Agency National Recommended 

Water Quality Criteria, and (B) mean instantaneous loads of cadmium relative to percentiles of the data at synoptic sampling sites in 

the Pike Hill, VT, study area.

Surface-Water Quality 29
Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

0 0.5 1 MILE

0 0.5 1 KILOMETER

Base from U.S. Geological Survey

West Topsham, 1981, 1:24,000 and

East Corinth, 1973, 1:24,000

Vermont State Plane Coordinate System

44°05'

A

Pike Hill Brook

Pike Hill Brook

Cookville Brook

Unnamed tributary 

to Cookville Brook

Union

Mine Eureka

Mine

Smith Mine

Pike

Hill

2

1 3

10

4

7

6

5

72° 17' 72° 15' 72° 13'

44° 03'

44°04'

9

8

44°05'

B

EXPLANATION 

 Sampling site with 

 identification

 Greater than 75th 

 percentile

 50th to 75th 

 percentile

 Less than 25th 

 percentile

 Mine

Copper

EXPLANATION 

Sampling site 

 with identification

Greater than acute 

 toxicity standard

Greater than chronic

 and less than acute 

 standards

 Less than chronic 

 toxicity standard

 Mine

2

2

Figure 16. (A) Median concentrations of copper in relation to U.S. Environmental Protection Agency National Recommended Water 

Quality Criteria, and (B) mean instantaneous loads of copper relative to percentiles of the data at synoptic sampling sites in the Pike 

Hill, VT, study area.

30 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
EXPLANATION

Number of samples

 Site 1—24

 Site 4—9

 Site 5—19

Multiple comparison group - A

90th percentile

75th percentile

50th percentile (median)

25th percentile

10th percentile

CONCENTRATION, IN MICROGRAMS PER LITER

INSTANTANEOUS LOAD, IN KILOGRAMS PER DAY

D

0.001

10

100

A

B

B

1

COPPER

0.01

0.1

E

Site 1 Site 4 Site 5

A

SAMPLING SITE

1

ZINC

10

10,000

1,000

100

B

C

A

0.01

100

A

B

C

0.1

CADMIUM

10

1

B

A

CADMIUM

B B

0.0001

1

0.001

0.1

0.01

A

C

A

1

COPPER

100

100,000

10,000

1,000

B

10 C

F

Site 1 Site 4 Site 5

0.001

10

100

A

B B

1

ZINC

SAMPLING SITE

0.01

0.1

A

Figure 17. A comparison of (A) concentrations of cadmium, (B) instantaneous loads of cadmium, (C) concentrations of copper, 

(D) instantaneous loads of copper, (E) concentrations of zinc, and (F) instantaneous loads of zinc among the three continuously 

monitored sites in the Pike Hill, VT, study area.

Surface-Water Quality  31
Figure 18. Streamflow conditions at site 1 during early snowmelt and rain (April 2, 2005) and snowmelt (April 11, 2005), and 

graphs showing the distribution of concentrations of copper and zinc in relation to maximum streamflows resulting from early 

snowmelt and rain (April 2 to 4, 2005), and from snowmelt (April 5 to 11, 2005) at (A) Pike Hill Brook above Richardson Road 

near Bradford, VT, station 01139830, site 1; and (B) Pike Hill Brook at Pike Hill Road near Bradford, VT, station 01139838, site 5.

April 2, 2005 April 11, 2005

1,000

10,000

100,000

A

0.4

0.8

1.2

1.6

2.0

Site 1, station 01139830

0

1.8

1.4

1.1

0.6

0.2

1

10

100

0

10

20

30

40

50

60

70

80

90

100

April 2005

DATE

29 30 31 1 2 3 4 5 6 7 8 9 10 11

March 2005

RAIN, IN INCHES PER HOUR

0

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0.36

0.40

STREAMFLOW, IN CUBIC FEET PER SECOND

EXPLANATION

 Copper Streamflow

 Zinc Rainfall

CONCENTRATION, IN MICROGRAMS PER LITER

B

Site 5, station 01139838

32 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Concentrations of Cu and Zn in relation to the instantaneous 

streamflow at site 1 from March 29, 2005 to April 11, 2005 

are graphically shown in figure 18A. Hourly rain totals 

recorded at USGS streamflow-gaging station 01139800 

East Orange Branch at East Orange, VT, are also shown in 

figure 18A. Concentrations of Cu and Zn in relation to the 

instantaneous streamflow at site 5 from March 29, 2005 to 

April 11, 2005 are graphically shown in figure 18B.

Samples were collected on March 29, 2005 to 

document conditions before the spring snowmelt. Samples 

were collected on April 2 and 3, 2005 to document conditions 

during the rise in streamflow resulting from early spring 

snowmelt and rain. Samples were collected on April 4, 2005 

to document conditions during the recession in streamflow. 

Samples were collected at site 1 on April 9 and 11, 2005 to 

document conditions during the rise in streamflow resulting 

from snowmelt only.

At sites 1 and 5, the maximum concentrations of Al, Fe, 

Cd, Cu, and Zn were observed during the early spring rains 

and snowmelt (April 3 and 4, 2005). At site 1 the maximum 

concentrations were not at the maximum streamflow sampled, 

whereas at site 5 the maximum concentrations were at the 

maximum streamflow sampled (fig. 18). Samples collected at 

high streamflows at site 1 (April 9 and 11, 2005) had lower 

concentrations of trace elements than those observed during early spring rains and snowmelt, most likely the result of 

flushing of the efflorescent sulfate salts from the waste rock 

during early spring snowmelt and rains and dilution from 

snowmelt during high streamflows. Maximum concentrations of SO4

, Fe, and Cu were observed during the maximum 

streamflow sampled on April 3, 2005, whereas the maximum 

Al, Cd, and Zn concentrations were observed during the recession in streamflow on April 4 for site 1. Early spring rains 

probably flushed the mine wastes and pooled mine waters, 

thus increasing the trace-element concentrations in Pike Hill 

Brook. The difference in timing for the maximum observed Al 

and Fe concentrations at site 1 was likely the result of changes 

in pH and its effects on the precipitation of these elements. 

The timing of the maximum concentrations of Cd, Cu, and Zn 

at site 1 may be related to the order of adsorption or desorption to Fe hydroxides with changes in pH. The timing of the 

maximum observed concentrations of Al, Cd, Cu, Fe, Zn, and 

SO4

 at site 5 may reflect the travel time required for waters 

from site 1 to reach site 5.

Measured and Estimated Constituent 

Concentrations and Loads

Concentrations of SO4, Ca, Al, Fe, Cd, Cu, and Zn at 

site 1 and Ca at sites 4 and 5 were estimated using multiple 

linear regressions. Regression equations were developed using 

streamflow, specific conductance, pH, and water temperature 

as variables to estimate concentrations of SO4

, Ca, Al, Fe, Cd, 

Cu, and Zn at site 1. The regression equations are listed in 

table 7. In general, the estimated concentrations were similar 

to the measured concentrations (fig. 19). The R2

 for the regression equations ranged from 0.82 to 0.96, whereas the MSE for 

regression equations ranged from 0.031 to 0.17 (table 7).

The regression analysis was applied to the continuous 

water-quality data recorded at site 1 to compute estimated 

daily mean concentrations of SO4

, Ca, Al, Fe, Cd, Cu, and Zn, 

and at sites 4 and 5 to compute estimated daily mean concentrations of Ca (fig. 20, table 8). All estimated Al, Cd, Cu, 

and Zn concentrations were above acute and chronic toxicity 

standards. All estimated Fe concentrations were above chronic 

toxicity standards.

Seasonal and annual loads were estimated for SO4

, Ca, 

Al, Fe, Cd, Cu, and Zn at site 1 using the estimated daily mean 

concentrations and the daily mean streamflow record. Seasonal and annual loads were estimated at site 5 using LOADEST for the dissolved and total SO4

, Al, Fe, Cd, Cu, and Zn 

phases and using the estimated daily mean concentrations and 

daily mean streamflow record for Ca. Summer and fall loads 

were estimated at site 4 using LOADEST for the dissolved 

and total SO4

, Al, Fe, Cd, Cu, and Zn phases and using the 

estimated daily mean concentrations and daily mean streamflow record for Ca. The LOADEST regression equations are 

listed in table 9. Annual loads were estimated for the period of 

January to December 2005.

Annual loads for dissolved SO4

 and Ca were greater at 

site 5 than at site 1 (fig. 21, table 10). The ratio of total to 

dissolved annual loads was about 1 for Al, Cd, Cu, and Zn at 

site 1 (table 10). Annual loads for dissolved Al and Fe were 

greater at site 1 than at site 5 (fig. 20, table 10). Annual 

loads for total Al, however, were similar at sites 1 and 5, 

whereas the annual loads for total Fe were greater at site 1 

than at site 5 (fig. 21, table 10). Annual loads for dissolved 

Cd and Zn at site 1 were about four to five times greater than 

at site 5, whereas the annual load for dissolved Cu at site 1 

was about seventeen times greater than at site 5 (fig. 21, 

table 10). Annual loads for total Cd and Zn at site 1 were 

about three times greater than at site 5, whereas the annual 

load for total Cu at site 1 was about six times greater than 

at site 5.

Dissolved and total loads for SO4

, Ca, Al, Fe, Cd, Cu, and 

Zn varied seasonally. Minimum seasonal loads were estimated 

for the summer except for dissolved Al at site 5, which was 

estimated for the winter (fig. 21, table 10). The maximum 

seasonal loads were estimated for the spring and fall except 

for SO4

 at site 5, which was estimated for the winter (fig. 21, 

table 10). The ratio of dissolved to total loads at site 5 for 

Al, Fe, Cd, Cu, and Zn sharply decreased during the spring 

relative to the other seasons. Dissolved SO4

 loads increased 

from site 1 to 4 and decreased from site 4 to site 5 during the 

summer and fall (fig. 21, table 10). An increase in dissolved 

loads was estimated from site 4 to site 5 for the summer and 

fall for Al and for the summer for Fe. Total Al and Fe loads, 

however, decreased with distance from site 1 during the 

summer and fall (fig. 21, table 10). Total and dissolved Cd, 

Cu, and Zn loads generally decreased with distance from site 1 

during the summer and fall (fig. 21, table 10).

Surface-Water Quality  33
Table 7. Regression equations for estimating concentrations of sulfate, calcium, aluminum, iron, cadmium, copper, and zinc at the 

three continuously monitored sites in the Pike Hill, VT, study area.

[MSE, mean square error; R2, coefficient of determination; SC, specific conductance; Q, streamflow; Temp, water temperature; log, logarithm. Location for 

sites is shown on figure 1]

Constituent Phase Equation MSE R2

Concentration Pike Hill Brook above Richardson Road near Bradford, VT (station 01139830, site 1)

Sulfate (SO4

) Dissolved log10(SO4) = 1.12log10(SC) – 0.683 0.033 0.94

Calcium (Ca) Dissolved log10(Ca) = 0.299log10(SC) – 0.137log10(Q) + 0.868 .042 .96

Aluminum (Al) Dissolved log10(Al) = 1.346log10(SC) + 0.068log10(Q) + 2.542log10(pH) – 1.3 .04 .89

Aluminum (Al) Total log10(Al) = 1.341log10(SC) + 0.075log10(Q) + 2.23log10(pH) – 1.106 .031 .94

Iron (Fe) Dissolved log10(Fe) = 2.686log10(SC) + 0.355log10(Q) – 3.163 .15 .85

Iron (Fe) Total log10(Fe) = 2.455log10(SC) + 0.393log10(Q) – 2.383 .17 .82

Cadmium (Cd) Dissolved log10(Cd) = 1.905log10(SC) + 0.282log10(Q) – 0.008(Temp) – 3.99 .077 .94

Cadmium (Cd) Total log10(Cd) = 1.909log10(SC) + 0.341log10(Q) – 4.013 .09 .91

Copper (Cu) Dissolved log10(Cu) = 1.919log10(SC) + 0.462log10(Q) – 1.589 .086 .94

Copper (Cu) Total log10(Cu) = 1.954log10(SC) + 0.459log10(Q) – 1.687 .084 .94

Zinc (Zn) Dissolved log10(Zn) = 1.418log10(SC) + 0.118log10(Q) – 0.558 .04 .95

Zinc (Zn) Total log10(Zn) = 1.447log10(SC) + 0.122log10(Q) – 0.638 .04 .96

Concentration Pike Hill Brook at Pike Hill Road west crossing near Bradford, VT (station 01139833, site 4)

Calcium (Ca) Dissolved log10(Ca) = 0.299log10(SC) – 0.137log10(Q) + 0.868 .042 .96

Concentration Pike Hill Brook at Pike Hill Road near Bradford, VT (station 01139838, site 5)

Calcium (Ca) Dissolved log10(Ca) = 0.299log10(SC) – 0.137log10(Q) + 0.868 .042 .96

34 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
MEASURED ZINC CONCENTRATION,

IN MICROGRAMS PER LITER

MEASURED COPPER CONCENTRATION,

IN MICROGRAMS PER LITER

A

Dissolved Ca

 %Diff = –0.1%

|%Diff| = 7.9%

Line of best fit

10

100

10 100

ESTIMATED CALCIUM CONCENTRATION,

IN MILLIGRAMS PER LITER

B

Line of best fit

100

1,000

100 1,000

ESTIMATED SULFATE CONCENTRATION,

IN MILLIGRAMS PER LITER

Dissolved SO4

 % Diff = –0.9%

|% Diff| = 4.9%

Total Cu

 % Diff = –1.8%

|% Diff| = 14.9%

 Dissolved Cu

 % Diff = –1.8%

|% Diff| = 15.9%

F

Line of best fit

1,000

10,000

1,000 10,000

ESTIMATED COPPER CONCENTRATION,

IN MICROGRAMS PER LITER

EXPLANATION

 Dissolved concentration

Total concentration

G

ESTIMATED ZINC CONCENTRATION,

Line of best fit

IN MICROGRAMS PER LITER

Total Zn

 % Diff = –0.2%

|% Diff| = 6.9%

 Dissolved Zn

 % Diff = –0.4%

|% Diff| = 7.2%

1,000

10,000

1,000 10,000

E

Line of best fit

1

100

1 100

ESTIMATED CADMIUM CONCENTRATION,

IN MICROGRAMS PER LITER

10

10

Dissolved Cd

 % Diff = –12.9%

|% Diff| = 21.1%

Total Cd

 % Diff = –9.0%

|% Diff| = 19.2%

D

Line of best fit

1,000

1,000,000

1,000 1,000,000

ESTIMATED IRON CONCENTRATION,

IN MICROGRAMS PER LITER

10,000

10,000

100,000

100,000

Total Fe

% Diff = –6.7%

|%Diff| = 31.1%

Dissolved Fe

 % Diff = –5.2%

|% Diff| = 28.5%

C

Line of best fit

4,000

16,000

4,000 16,000

ESTIMATED ALUMINUM CONCENTRATION,

IN MICROGRAMS PER LITER

6,000 8,000 10,000 12,000 14,000

Dissolved Al

 % Diff = –0.2%

|% Diff| = 7.2%

Total Al

% Diff = –0.6%

|%Diff| = 5.3% 6,000

8,000

10,000

12,000

14,000

% Diff—Median percent difference between instantaneous measured 

 concentrations and instantaneous estimated concentrations 

|% Diff|—Median of the absolute value of the percent difference between instantaneous 

 measured concentrations and instantaneous estimated concentrations

MEASURED IRON CONCENTRATION,

IN MICROGRAMS PER LITER

MEASURED SULFATE CONCENTRATION,

IN MILLIGRAMS PER LITER

MEASURED CALCIUM CONCENTRATION,

IN MILLIGRAMS PER LITER

MEASURED ALUMINUM CONCENTRATION,

IN MICROGRAMS PER LITER

MEASURED CADMIUM CONCENTRATION,

IN MICROGRAMS PER LITER

Figure 19. The relation of measured to estimated concentrations of (A) calcium at the three continuously monitored sites in 

the Pike Hill, VT, study area; and (B) sulfate; (C) aluminum; (D) iron; (E) cadmium; (F) copper; and (G) zinc at Pike Hill Brook above 

Richardson Road near Bradford, VT, station 01139830, site 1.

Surface-Water Quality  35
D

250,000

Oct 1 Jan 1

2005

DATE

Jan 1 Apr 1 Jul 1 Oct 1

2004

200,000

150,000

100,000

50,000

0

IRON,

IN MICROGRAMS PER LITER

A

B

ALUMINUM,

IN MICROGRAMS PER LITER

C

25,000

20,000

15,000

10,000

5,000

0

SULFATE,

IN MILLIGRAMS PER LITER

300

400

500

600

700

800

200

900

CALCIUM,

IN MILLIGRAMS PER LITER

0

20

40

60

80

100

120

Figure 20. Estimated daily mean concentrations of (A) calcium at the three continuously monitored sites in the Pike Hill, VT, 

study area; and (B) sulfate; (C) aluminum; (D) iron; (E) cadmium; (F) copper; and (G) zinc at Pike Hill Brook above Richardson 

Road near Bradford, VT, station 01139830, site 1, from November 2004 to December 2005.

36  Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Figure 20. Estimated daily mean concentrations of (A) calcium at the three continuously monitored sites in the Pike Hill, VT, 

study area; and (B) sulfate; (C) aluminum; (D) iron; (E) cadmium; (F) copper; and (G) zinc at Pike Hill Brook above Richardson 

Road near Bradford, VT, station 01139830, site 1, from November 2004 to December 2005.—Continued

Surface-Water Quality  37

Oct 1 Jan 1

2005

DATE

Jan 1 Apr 1 Jul 1 Oct 1

2004

E

F

ZINC,

IN MICROGRAMS PER LITER

G

10,000

8,000

6,000

4,000

2,000

0

COPPER,

IN MICROIGRAMS PER LITER

5,000

10,000

15,000

20,000

25,000

30,000

0

35,000

CADMIUM,

IN MICROGRAMS PER LITER

0

20

40

60

80

100

120

EXPLANATION

 Estimated, total concentration, site 1

 Estimated, dissolved concentration, site 1

 Estimated, dissolved concentration, site 4

 Estimated, dissolved concentration, site 5
Table 8. Summary statistics for estimated daily mean concentrations of sulfate, calcium, aluminum, iron, cadmium, copper, and 

zinc from regression models at the three continuously monitored sites in the Pike Hill, VT, study area. 

[mg/L, milligrams per liter; μg/L, micrograms per liter. Location for sites is shown on figure 1]

Constituent Phase

Concentration 

Minimum Mean Median Maximum

Pike Hill Brook above Richardson Road near Bradford, VT (station 01139830, site 1)

Sulfate (mg/L) Dissolved 208 323 283 836

Calcium (mg/L) Dissolved 48 68 64 104

Aluminum (μg/L) Dissolved 4,840 7,330 6,940 22,600

Aluminum (μg/L) Total 4,940 7,400 7,040 23,000

Iron (μg/L) Dissolved 7,830 19,800 13,000 213,000

Iron (μg/L) Total 9,320 24,100 15,800 222,000

Cadmium (μg/L) Dissolved 9.2 17.2 14 102

Cadmium (μg/L) Total 7.4 15.9 12 95.8

Copper (μg/L) Dissolved 1,340 3,820 2,570 24,200

Copper (μg/L) Total 1,370 3,870 2,580 25,100

Zinc (μg/L) Dissolved 1,570 2,490 2,190 9,000

Zinc (μg/L) Total 1,560 2,500 2,190 9,240

Pike Hill Brook at Pike Hill Road, west crossing, near Bradford, VT (station 01139833, site 4)

Calcium (mg/L) Dissolved 25 40 40 54

Pike Hill Brook at Pike Hill Road near Bradford, VT (station 01139838, site 5)

Calcium (mg/L) Dissolved 17 30 29 46

38  Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Table 9. Regression equations for estimating loads of sulfate, aluminum, iron, cadmium, copper, and zinc at Pike Hill Brook at Pike Hill Road, west crossing, and Pike Hill 

Brook at Pike Hill Road near Bradford, VT. 

[MSE, mean square error; R2, coefficient of determination; Q, centered streamflow; ln, natural logarithm; dtime, centered decimal time, in years. Location for sites is shown on figure 1]

Constituent Phase Equation MSE R2

Load Pike Hill Brook at Pike Hill Road, west crossing, near Bradford, VT (station 01139833, site 4)

Sulfate (SO4) Dissolved ln(SO4) = 5.6564 + 0.8410ln(Q) – 0.0323ln(Q2) – 0.198sin(2πdtime) – 0.758cos(2πdtime) – 0.1184dtime + 2.7005dtime2 0.061 0.98

Aluminum (Al) Dissolved ln(Al) = -3.3902 + 0.3929ln(Q) – 0.3465ln(Q2) + 0.0825sin(2πdtime) + 0.3768cos(2πdtime) + 0.4758dtime .159 .80

Aluminum (Al) Total ln(Al) = -0.2799 + 2.1387ln(Q) + 0.8506dtime .349 .95

Iron (Fe) Dissolved ln(Fe) = -2.4362 + 2.2209ln(Q) + 0.8039ln(Q)2 – 1.0391dtime .613 .92

Iron (Fe) Total ln(Fe) = 1.0884 + 2.194ln(Q) .626 .90

Cadmium (Cd) Dissolved ln(Cd) = -5.5781 + 1.5989ln(Q) + 0.2501ln(Q)2 .337 .91

Cadmium (Cd) Total ln(Cd) = -5.4561 + 1.6028ln(Q) + 0.2199ln(Q)2 .336 .91Copper (Cu) Dissolved ln(Cu) = -2.9096 + 2.335ln(Q) + 0.5036ln(Q2) + 0.7047sin(2πdtime) + 0.1365cos(2πdtime) .221 .97

Copper (Cu) Total ln(Cu) = -0.5698 + 2.3372ln(Q) .599 .91

Zinc (Zn) Dissolved ln(Zn) = -0.422 + 1.5776ln(Q) .44 .87

Zinc (Zn) Total ln(Zn) = -0.2725 + 1.5759ln(Q) .399 .88

Load Pike Hill Brook at Pike Hill Road near Bradford, VT (station 01139838, site 5)

Sulfate (SO4) Dissolved ln(SO4) = 5.8695 + 0.8644ln(Q) – 0.1243ln(Q2) – 0.3077sin(2πdtime) – 0.2965cos(2πdtime) .082 .94

Aluminum (Al) Dissolved ln(Al) = -1.7750 + 1.397ln(Q) + 0.1172ln(Q2) + 0.6302sin(2πdtime) + 0.1686cos(2πdtime) .069 .97

Aluminum (Al) Total ln(Al) = 0.4339 + 2.3288ln(Q) + 0.3748ln(Q2) – 0.5015sin(2πdtime) – 0.543cos(2πdtime) .333 .97

Iron (Fe) Dissolved ln(Fe) = 0.1137 + 0.7294ln(Q) – 1.1607dtime .415 .68

Iron (Fe) Total ln(Fe) = 1.7552 + 1.9065ln(Q) + 0.4655ln(Q)2 – 0.6532dtime .336 .95

Cadmium (Cd) Dissolved ln(Cd) = -5.3819 + 1.0413ln(Q) – 0.1435ln(Q)2 .193 .89

Cadmium (Cd) Total ln(Cd) = -5.3218 + 1.4706ln(Q) + 0.2197ln(Q)2 – 0.3042sin(2πdtime) – 0.072cos(2πdtime) .066 .98

Copper (Cu) Dissolved ln(Cu) = -1.3764 + 1.1708ln(Q) + 0.6534dtime .182 .91

Copper (Cu) Total ln(Cu) = -0.6892 + 1.8529ln(Q) + 0.2599ln(Q)2 + 0.3985dtime .091 .98

Zinc (Zn) Dissolved ln(Zn) = -0.6342 + 0.9074ln(Q) – 0.1523ln(Q)2 – 0.6475sin(2πdtime) – 0.1409cos(2πdtime) .213 .91

Zinc (Zn) Total ln(Zn) = -0.4285 + 1.4581ln(Q) + 0.1638ln(Q)2 – 0.6199sin(2πdtime) – 0.1558cos(2πdtime) .073 .98

Surface-Water Quality  39
A. Sulfate B. Calcium

F. Copper

G. Zinc

E. Cadmium

C. Aluminum D. Iron

LOAD, IN KILOGRAMS PER DAY

0

50

100

150

200

250

300

350

400

1 5 1 5 1 5 1 4 5 1 4 5

Annual Winter Spring Summer Fall

0

50

100

150

200

250

300

350

400

1 5 1 5 1 5 1 5 4 1 5 4

Annual Winter Spring Summer Fall

0

5

10

15

20

25

1 5 1 5 1 5 1 5 4 1 5 4

Annual Winter Spring Summer Fall

0

5

10

15

20

25

30

35

40

45

50

1 5 1 5 1 5 1 5 4 1 5 4

Annual Winter Spring Summer Fall

1 5 1 5 1 5 1 5 4 1 5 4

Annual Winter Spring Summer Fall

0

0.005

0.01

0.015

0.02

0.025

0.03

0

1

2

3

4

5

6

7

8

1 5 1 5 1 5 1 5 4 1 5 4

Annual Winter Spring Summer Fall

SITE AND SEASON

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1 5 1 5 1 5 1 5 4 1 5 4

Annual Winter Spring Summer Fall

SITE AND SEASON

EXPLANATION

 Total load

Dissolved load

1 Site number

Figure 21. Annual and seasonal loads for (A) sulfate, (B) calcium, (C) aluminum, (D) iron, (E) cadmium, (F) copper, and (G) zinc 

at the three continuously monitored sites in the Pike Hill, VT, study area.

40 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Table 10. Annual and seasonal loads estimated for the three continuously monitored sites in the Pike Hill, VT, study area.

[Winter, December to February; Spring, March to May; Summer, June to August; Fall, September to November; --, no data. Refer to figure 1 and table 1 for 

site name, station number, and location]

Season 

site

Load, in kilograms per day

Sulfate 

dissolved

Calcium 

dissolved

Aluminum Iron Cadmium Copper Zinc

Dissolved Total Dissolved Total Dissolved Total Dissolved Total Dissolved Total

Annual

Site 1 216 40 5.43 5.50 18.7 23.3 0.015 0.015 3.85 3.88 1.87 1.88

Site 5 259 416 .13 5.91 .87 9.98 .003 .005 .22 .62 .44 .68

Winter

Site 1 166 36 3.60 3.68 9.10 11.8 .009 .008 2.11 2.12 1.31 1.31

Site 5 338 391 .06 1.00 .92 3.41 .003 .004 .19 .33 .62 .66

Spring

Site 1 290 57 8.14 8.15 22.9 29.6 .021 .020 5.35 5.37 2.51 2.51

Site 5 326 608 .25 20.56 1.54 28.4 .005 .010 .33 1.36 .67 1.32

Summer

Site 1 84 19 2.10 2.08 3.54 4.43 .004 .003 .76 .76 .61 .61

Site 4 95 65 .03 1.07 .41 4.83 .005 .005 .19 1.02 .67 .76

Site 5 86 246 .10 .64 .50 2.41 .002 .001 .10 .18 .11 .13

Fall

Site 1 320 47 7.72 7.92 38.6 46.4 .028 .026 7.04 7.15 3.01 3.04

Site 4 353 145 .02 6.33 2.27 20.8 .017 .019 1.30 4.70 2.08 2.38

Site 5 289 414 .13 1.30 .53 5.48 .003 .004 .25 .61 .38 .58

Effect of Wetlands on Chemical Constituents

Wetlands can interact chemically with ARD through 

aerobic and anaerobic pathways. The aerobic pathway is 

dominated by the oxidation of reduced iron, with the potential for precipitation of ferric hydroxides and the associated 

adsorption of metals. The anaerobic pathway is dominated by 

sulfate-reducing bacteria, which consume sulfate and organic 

matter to produce sulfide and alkalinity. The resultant sulfide 

is available to remove metals through the precipitation of 

sulfide minerals in the wetlands. The anaerobic pathway also 

offers the possibility of reducing previously formed hydrated 

ferric hydroxides.

A series of wetlands occurs along Pike Hill Brook 

between the mine site and the confluence with the Waits River 

(fig. 1). Throughout the wetlands, Pike Hill Brook maintains a 

discrete channel. Thus, water that discharges from the wetlands includes both ground and surface waters that have interacted with the wetlands, and surface waters in Pike Hill Brook 

that have flowed through with minimal interaction. To evaluate 

the potential of aerobic and anaerobic pathways, water was 

sampled in August 2005 from Pike Hill Brook upstream 

and downstream from the wetlands during base-flow conditions to maximize geochemical signatures attributable to the 

wetlands (fig. 1, table 1). Additional surface waters unrelated 

to the mine site that were contributing to the wetlands also 

were sampled. The Pike Hill Brook tributary at Brook Road 

(site 5A) was the only tributary to have significant streamflow 

during the sampling (fig. 1, table 11). Streamflows for sites 1, 

4, and 5 were measured at the continuous streamflow-gaging 

stations. Streamflows for sites 3, 6, and 7 were estimated on 

the basis of drainage area. Streamflow measurements were 

made at Pike Hill Brook at Pike Hill Road, northwest crossing 

(site 2A) and at site 5A (table 11). Streamflows at sites 4, 5, 

and 6 indicated that ground water contributes over half of the 

discharge from the wetlands.

The concentrations of dissolved Fe entering the wetlands 

were low, and it appears unlikely that oxidation of ferrous Fe 

and precipitation of ferric hydroxides have a significant effect 

on trace metals in the wetlands through sorption (fig. 22). 

Total Fe concentrations, however, were about three times the 

dissolved Fe concentrations entering the wetlands. Therefore, 

a large amount of the Fe entering the wetlands is in particulate form and may have transported sorbed copper and other 

trace metals. Thus, aerobic activity related to oxidation of iron 

within the wetlands is not likely to play an important role in 

metal cycling in the watershed.

Surface-Water Quality 41
 Sample

 Below detection limit

 1 4 5

1

100

100,000

SAMPLING SITE

10

10,000

1,000

0 2 3 6 7 8

CONCENTRATION OF IRON, IN MICROGRAMS PER LITER

Site 0

 Site 1

Site 2A Site 3 Site 5A

Site 4

Site 5 Site 6

Site 7

Figure 22. Concentrations of dissolved iron at synoptic sampling sites in the Pike Hill, VT, study area, 

August 3, 2005.

Table 11. Selected parameters for sampling sites associated with the wetlands in 

the Pike Hill, VT, study area, August 3, 2005.

[ft3/s, cubic feet per second; μg/L, micrograms per liter; mg/L, milligrams per liter; --, no value; <, less 

than; e, estimated. Refer to figure 1 and table 1 for site name, station number, and location]

Site number

(table 1; figure 1)

Streamflow

(ft3

/s)

Dissolved concentrations

pH Iron1

(μg/L)

Sulfate

(mg/L)

0 -- 4.2 717 373

1 0.04 3.2 10,600 342

2A .11 6.8 <20 125

3 e.14 6.8 <20 95

4 .24 6.9 59 50

5A .14 8.2 <20 11

5 .92 7.3 130 8.0

6 e1.1 7.4 163 5.7

7 e1.2 8.3 52 6.7

1

 Analyzed using Inductively Coupled Plasma.

42 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
above and below the wetland (sites 4A and 5, respectively). 

The difference in the macroinvertebrate assemblages between 

sites 4A and 5, when compared to changes between other 

consecutive sites along Pike Hill Brook, could indicate the 

relative degree that the wetland reduced the affects of ARD on 

the macroinvertebrate assemblages. Because site 4A was not 

part of the initial site network for water-quality sampling, the 

Hazard Index for site 4A was estimated by interpolation, 

based on the drainage area of the site and the relation between 

the drainage area and the median concentration of metals at 

sites 3, 4, and 5.

An ordination of the macroinvertebrate assemblage 

data was done with the use of correspondence analysis to 

determine the differences among sites based on patterns 

in the assemblage structure (taxa richness and abundance 

of organisms). The correspondence analysis indicated that 

the assemblage structure of the macroinvertebrates was 

related to drainage area as well as contamination at the sites, 

determined from correlations of the first-axis site scores of the 

correspondence analysis with the drainage area (spearman rho 

= 0.936) and with the Hazard Index (spearman rho = 0.505). 

These results also indicated that stream size (= drainage 

area) affected the assemblage structure most strongly. The 

consequence of comparing macroinvertebrate assemblages 

among sites with dissimilar drainage areas is that the streams 

are ecologically very different, and this difference is a primary 

factor in the structure of the macroinvertebrate assemblage at 

a site. For example, sites 8 and 9 have relatively wide channels 

with open canopy, which can contribute to the production of 

benthic algae as a primary food base. Conversely, site 2 is a 

closed canopy headwater stream that is not shown on a USGS 

1:24,000-scale map, has summer flows in a channel that is 

typically less than 3.28 ft (1 m) wide, and has a food base 

that comes mainly from fallen leaf litter. Among the sites, 

therefore, physical differences related to watershed size as 

well as the chemical differences caused by ARD were factors 

that would likely affect the macroinvertebrate assemblages.

To investigate the effects of ARD on changes in the 

macroinvertebrate assemblages, it is important to take into 

account that the sites not directly affected by ARD were the 

smallest (2) and largest (8 and 9) among all the study sites 

in terms of drainage areas and stream size. Although these 

sites were appropriate for use as water-quality indicators to 

characterize relatively uncontaminated sites in this study, 

the biological assemblages at these sites were not directly 

comparable to the sites affected by ARD. Furthermore, a 

comparison of site 2 with sites 8 and 9 showed they had very 

different macroinvertebrate assemblages (appendix 1), which 

are likely a result of stream size and not ARD. Therefore, 

to determine the effect of ARD on macroinvertebrate 

assemblages, several comparisons were made only among 

the sites most affected by ARD (sites 1, 3–7, and 10). It 

is important to note, however, that the macroinvertebrate 

data collected at site 2 (appendix 1) indicated the potential 

for a diverse macroinvertebrate assemblage at a headwater 

stream, such as site 1, if ARD was absent. In this context, 

Concentrations of SO4

 showed a steady decrease downstream (fig. 23). Unaffected tributaries (sites 2 and 5A) had 

sulfate concentrations that were comparable to those in Pike 

Hill Brook downstream from the wetlands at sites 5, 6, and 7. 

Therefore, concentrations and loads of SO4

 may be unlikely 

to define unequivocally the role of the wetlands with regard 

to anaerobic bacterial sulfate reduction. However, sites 1, 2A, 

3, and 4 had similar loads. Sites 5, 6, and 7 had similar, but 

lower loads that indicated sulfate removal. Therefore, bacterial 

sulfate removal may have affected loads of SO4

.

Concentrations of Cu and Zn also decreased in Pike Hill 

Brook with distance downstream from the Eureka and Union 

mines (site 0) (figs. 24 and 25). Cu loads increased at site 5, 

downstream from the wetlands, whereas Zn loads decreased. 

Total concentrations of Cu were about twice the dissolved 

concentrations at site 4, upstream from the wetlands, but total 

and dissolved Zn concentrations were similar. The increase 

in Cu loads may reflect the reductive dissolution of ferric 

hydroxide particulates in anaerobic parts of the wetlands. 

Dissolved Fe concentrations increased at site 5, downstream 

from the wetlands (fig. 22), which is consistent with this 

hypothesis. The lack of a similar increase in Zn loads is 

consistent with most of the Zn load being in the dissolved 

form rather than the total form.

Biological Assessment of the Pike Hill 

Brook Watershed

To determine the effects of ARD on the macroinvertebrate assemblages at sites in the study area, the benthic 

macroinvertebrate data were compared with hazard quotients 

(HQ), which were based on median metal concentrations at 

the sampling sites. The HQ for each synoptic sampling site 

was calculated by dividing median concentrations of Cd, Cu, 

and Zn by their respective chronic toxicity value, then these 

HQ values were summed to provide a single Hazard Index 

value for each site (table 12). A Hazard Index often is used 

to represent the cumulative toxicity of multiple contaminants 

(U.S. Environmental Protection Agency, 1986). In this study, 

a Hazard Index greater than 1 indicates the median concentrations of Cd, Cu, and Zn exceed their additive chronic toxicity 

values. The relative toxicity of the ARD, therefore, is represented by the Hazard Index.

Benthic Macroinvertebrate Assemblages

Macroinvertebrate samples were collected at the 10 synoptic water-quality sites and at an additional site (4A) on Pike 

Hill Brook about 0.5 mi below site 4 and immediately above 

the dominant wetland in the basin. This wetland confines 

the flow of Pike Hill Brook for approximately 1.25 mi and is 

between site 4A and site 5 (fig. 1, table 1). Site 4A was added 

to allow a comparison of the macroinvertebrate assemblages 

Biological Assessment of the Pike Hill Brook Watershed 43
Figure 23. (A) Concentrations of dissolved sulfate, and (B) instantaneous loads of sulfate 

at sampling sites in the Pike Hill, VT, study area, August 3, 2005.

A

B

 CONCENTRATION OF SULFATE, IN MILLIGRAMS PER LITER LOAD OF SULFATE, IN GRAMS PER SECOND

4 10

1

100

SAMPLING SITE

10

1,000

0 2 6 8

Site 0 Site 1

Site 2A

Site 2 Site 5A

Site 3

Site 4

Site 5

Site 6 Site 7 Site 8 Site 9

0

0.10

0.20

0.30

0.40

SAMPLING SITE

0 1 2 3 4 5 6 7 8

Site 1 Site 2A

Site 5A

Site 3

Site 4

Site 5

 Site 6

Site 7

44 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Figure 24. (A) Concentrations of dissolved copper, and (B) instantaneous loads of copper 

at sampling sites in the Pike Hill, VT, study area, August 3, 2005.

A

B

 CONCENTRATION OF COPPER, IN MICROGRAMS PER LITER LOAD OF COPPER, IN MILLIGRAMS PER SECOND

4 10

0.1

SAMPLING SITE

10

0 2 6 8

Site 0

Site 1

Site 2A

Site 2

Site 3

Site 4

Site 5 Site 6 Site 7

Site 8

Site 9

0

0.2

0.3

2.1

2.2

SAMPLING SITE

0 1 2 3 4 5 6 7 8

Site 1

Site 2A

Site 3 Site 4

Site 5 Site 6

Site 7

0.1

100

10,000

1

1,000

Biological Assessment of the Pike Hill Brook Watershed 45
Figure 25. (A) Concentrations of dissolved zinc, and (B) instantaneous loads of zinc at 

sampling sites in the Pike Hill, VT, study area, August 3, 2005.

A

B

 CONCENTRATION OF ZINC, IN MICROGRAMS PER LITER LOAD OF ZINC, IN MILLIGRAMS PER SECOND

SAMPLING SITE

10

Site 0

Site 1

Site 2A

Site 3

Site 4

Site 5 Site 6

Site 7

Site 2 Site 5A

0

1.5

2.0

2.5

3.0

SAMPLING SITE

0 1 2 3 4 5 6 7 8

Site 1

Site 2A

Site 3

Site 4

Site 5

 Site 6

Site 7

1.0

100

10,000

1

1,000

0 1 2 3 4 5 6 7 8

0.5

Site 5A

46  Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Table 12. Hazard Index values and the Vermont Department 

of Environmental Conservation (VT-DEC) assessment of 

U.S. Geological Survey macroinvertebrate assemblage data for 

sites in the Pike Hill, VT, study area.

[Values in BOLD are downgradient from mines. Refer to figure 1 and table 1 

for site name, station number, and location]

Site number

(table 1; fig. 1) Hazard Index VT-DEC assessment

1 503 Poor

2 .2 Good

3 17 Poor

4 7.9 Poor

4A 6.9 Poor

5 1.9 Fair

6 1.7 Good-fair

7 1.2 Fair

8 .1 Very good

9 .2 Very good

10 1.0 Good

the comparison between sites 1 and 2 is relevant because 

the change in the macroinvertebrate assemblages moving 

downstream on Pike Hill Brook was more a function of ARD 

than basin area.

The most apparent effects on the macroinvertebrate 

assemblages caused by high contaminant levels from ARD 

(represented by Hazard Index values) were seen in the 

abundance of organisms and richness of taxa. Although other 

metrics and indices indicted a response to ARD, additional 

investigation showed that these responses were correlated to 

a general decrease in macroinvertebrate density (abundance) 

and richness. For example, an increase in the Hazard Index 

resulted in a decrease in three functional-group richness 

metrics that represent Filterers, Gatherers, and Predators; 

however, these three metrics were responding because taxa 

richness, in general, was decreasing, and not because a 

specific taxonomic group was being displaced by another.

A decrease in the macroinvertebrate abundance was 

strongly correlated to increasing values of the Hazard Index 

(rho = -0.929). This response was clearly indicated by the progressive decrease in Hazard Index with a concurrent increase 

in macroinvertebrate abundance among the Pike Hill Brook 

sites as their distance increased from the waste piles; the 

site closest to the waste piles (site 1) had the highest Hazard 

Index value and lowest abundance, whereas the site farthest 

from the waste piles (site 7) had the lowest Hazard Index 

value and highest abundance (fig. 26A). Site 1 was the most 

affected by ARD (Hazard Index = 503), and this site had an 

abundance value of 30 individuals (lowest of all sites), which 

was markedly less than the abundance of 539 individuals at 

site 2. Although sites 1 and 2 are not directly comparable (as 

explained above), a higher abundance would be expected at 

site 1, in the absence of ARD, because of its larger drainage 

area. Of the stations along Pike Hill Brook, site 7 was the most 

downstream and least affected by ARD, and had the highest 

macroinvertebrate abundance of 814 individuals.

In addition to a general decrease in taxa abundance with 

increasing ARD, the richness of certain taxonomic groups also 

decreased. The EPT (Ephemeroptera, Plecoptera, Trichoptera) 

richness is a metric commonly used to indicate the level of 

increased disturbance based on the loss of mayfly, stonefly, 

and caddisfly taxa (Barbour and others, 1999). At the ARD 

sites, however, the stoneflies appeared not quite as sensitive 

as the mayflies and the caddisflies. The likely reason for this 

is that stoneflies can be somewhat resistant to metals contamination and low pH, and the mayflies are typically the most 

sensitive to ARD (Earle and Callaghan, undated, accessed 

on March 15, 2006 at http://www.leo.lehigh.edu/envirosci/

enviroissue/amd/links/wildlife1.html). An example of this type 

of tolerance to ARD was seen at site 1, where two of the six 

taxa collected were stoneflies. The ET Richness (Ephemeroptera + Trichoptera), therefore, responded more strongly to the 

Hazard Index than did EPT Richness (rho = -0.884 and -0.771, 

respectively). Neither mayflies nor caddisflies were present at 

site 1, and although downstream caddisfly richness increased 

steadily to site 5, mayflies were not present until site 4A 

(fig. 26B). Compared to the mayflies and caddisflies, Chironomids, as a group, often are regarded as more tolerant 

to disturbance, although the reason for this categorization 

has primarily been based on a relatively greater tolerance to 

organic pollution (Barbour and others, 1999). In contrast, however, Chironomid richness was fairly well correlated with the 

Hazard Index (rho = -0.837), indicating that some midge taxa 

were sensitive to ARD (fig. 26C). This finding was supported 

by the Chironomid richness of 19 at site 2, which was a value 

that was not reached until site 5.

Comparison of Assemblages with Vermont 

Bioassessment Metrics

The VT-DEC has conducted biological assessments of 

streams near Pike Hill mines since 1997 to determine the 

extent of effects from ARD. These assessments have evaluated 

macroinvertebrate and fish assemblages, and have consistently 

indicated that the standards for Class B Aquatic Life Support 

have not been met for the entire length of Pike Hill Brook 

(S. Fiske and R. Langdon, Vermont Department of Environmental Conservation, and J.F. Coles, U.S. Geological Survey, 

written commun., 2006). These ratings are most likely a 

direct result of the ARD because no other major stressor to 

the aquatic community was identified in the watershed. As a 

component of these assessments, the VT-DEC evaluated the 

Biological Assessment of the Pike Hill Brook Watershed 47
Figure 26. The relation of Hazard Index and (A) total abundance, (B) Mayfly plus caddisfly richness, and 

(C) Chironomid richness at sampling sites in the Pike Hill, VT, study area.

48  Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005

1,000

100

20

15

10

0

25

10

5

0

Sampling site with number

Sampling site with number

Sampling site with number

1

3

4 4A

5

6

10

TOTAL ABUNDANCE

A

6

MAYFLY PLUS CADDISFLY RICHNESS

5

7

10 5

6

4A

4

3

1

6

B

6

7 5

10 6

4A

4 3

1

20

15

HAZARD INDEX

1 10 100 1,000

CHIRONOMID RICHNESS

C

1 10 100 1,000

1 10 100 1,000

7
macroinvertebrate-assemblage data collected on August 29, 

2005 by the USGS (table 12). As typically done by VT-DEC, 

these assessments are based primarily on how the macroinvertebrate assemblage data compare to threshold values of 

eight biocriteria metrics, which are regarded by VT-DEC 

(appendix 2) as responsive to various stream impairments.

In addition, fish surveys by VT-DEC have been conducted along reaches of Pike Hill Brook that were near USGS 

sites 4 (in 1997 and 2002), 5 (in 1997), and 7 (in 2002 and 

2005), and all have been assessed as “Poor” on the basis of 

fish assemblages. Cookville Brook was surveyed for fish at 

USGS site 10, concurrent to the USGS macroinvertebrate 

sampling (in 2005), and it was assessed as “Excellent” on the 

basis of the fish assemblage.

To characterize the macroinvertebrate assemblages 

among sites in a way that was relevant to the biological 

assessments made by VT-DEC (S. Fiske and R. Langdon, 

Vermont Department of Environmental Conservation, and 

J.F. Coles, U.S. Geological Survey, written commun., 2006), 

five of the eight metrics used by VT-DEC were applied to 

the USGS macroinvertebrate data and then compared to 

median values of the metrics from Vermont reference sites. 

The metrics used were Density, Richness, EPT Index, Percent 

Model Affinity of Orders, and Pinkham-Pearson Coefficient 

of Similarity-Functional Groups (appendix 2). Metrics not 

used were EPT/EPT+Chironimidae, percent Oligochaeta, and 

Hilsenhoff Biotic Index, because they were likely to be more 

responsive to organic enrichment than to ARD. Based on 

information provided by VT-DEC, the USGS sites represented 

three stream types (headwaters = sites 1, 2, 3, 10; small highgradient streams (SHG) = sites 4, 4A, 5, 6, 7; and medium 

high-gradient streams (MHG) = sites 8, 9). By the use of this 

classification method, the assessment threshold values of 

the metrics were specific to the stream type. This approach, 

therefore, overcomes some of the problems associated with the 

influence of stream size on macroinvertebrate assemblages, as 

discussed previously.

The macroinvertebrate characterizations were made by 

first calculating the five metric values for the macroinvertebrate data (site metrics), then dividing each of these values by 

the respective metric value for reference sites (reference metrics). For this purpose, each reference metric was the median 

of the metric values from reference streams for the specific 

type (headwaters, SHG, or MHG). The quotient that resulted 

from dividing the site metric by the reference metric was 

multiplied by 100, which resulted in a standardized percentage 

value that was not, therefore, dependent on the stream type. To 

provide a single comprehensive value to relate the site metrics 

with reference metrics, the geometric mean was calculated for 

the five metric quotients, from which 100 was subtracted. This 

single value was termed the “site deviation from reference,” 

which characterized the difference between a sampling site 

and its respective reference site by deriving the average of the 

percentage difference between site-metric values and reference-metric values. A zero value would, therefore, result when 

the values of the site metrics were the same as the reference 

metrics; a positive or negative value would indicate the percent 

deviation above or below the reference metric.

The results of this analysis from the 11 sampling sites 

indicated that site deviation from reference values were 

highly correlated with the Hazard Index values (rho = -0.936) 

(fig. 27). This relation indicated a trend of gradually improving conditions in Pike Hill Brook along the continuum of sites 

from the waste-rock headwaters (site 2) to the end of the brook 

(site 7) before it enters the Waits River (fig. 28). Additionally, the wetland between sites 4A and 5 may have a mitigating effect on the water quality of Pike Hill Brook, possibly 

because it traps much of the sediment that was transported 

from the waste rock. A comparison between the qualitative 

assessment categories provided by VT-DEC and values of site 

deviation from reference indicates relative agreement among 

all sites. These results help confirm consistency in the evaluations of the sites, which increases the confidence in recognizing the level of ecological risk associated with each site.

Biological Assessment of the Pike Hill Brook Watershed 49
50

0

-50

-100

-1 0 1 2 3

HAZARD INDEX (LOG)

DEVIATION FROM REFERENCE, IN PERCENT

Site 8

Site 6

Site 9

Site 2

Site 10

Site 7

Site 5

Site 4 Site 3

Site 4A

Site 1

 Sites on Pike Hill Brook

 Sites not on Pike Hill Brook

Figure 27. The relation between 

values of site deviation from 

reference and the Hazard Index 

values (log) at sampling sites in the 

Pike Hill, VT, study area.

Figure 28. The relation of 

macroinvertebrate data at the 

Pike Hill, VT, study area to data 

from Vermont reference streams.

50

0

-50

-100

10 12 8 9

SAMPLING SITES

DEVIATION FROM REFERENCE, IN PERCENT

3 4 4A 5 6 7

Headwaters Small high gradient

Medium

high

gradient

Waste rock drainageLocation of wetland

 Sites on Pike Hill Brook

 Sites not on Pike Hill Brook

50 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Summary and Conclusions

The Pike Hill Superfund Site, placed on the U.S. Environmental Protection Agency (USEPA) National Priorities List 

in 2004, consists of three abandoned mines, the Eureka, the 

Smith, and the Union mines, and is in the town of Corinth, VT. 

The site is contributing trace elements to Pike Hill Brook and 

an unnamed tributary to Cookville Brook. The U.S. Geological Survey (USGS), in cooperation with USEPA, used an integrated (physical, chemical, and biological) approach to assess 

the current water-quality conditions in and around the Pike 

Hill Brook watershed and describe the fate and transport of 

contamination associated with the acid rock drainage (ARD).

A combination of continuous monitors and water-quality 

sampling was used to characterize the surface-water hydrology and water quality of Pike Hill Brook over an annual cycle. 

Continuous monitors were used at three sites on Pike Hill 

Brook to measure streamflow, specific conductance, pH, and 

water temperature from October 2004 to December 2005. 

Water samples were collected monthly for analysis of trace 

elements and major ions at the three continuously monitored 

sites from October 2004 to December 2005.

Water samples from the three continuously monitored 

sites showed that some concentrations of aluminum (Al), 

cadmium (Cd), copper (Cu), iron (Fe), and zinc (Zn) exceeded 

the USEPA National Recommended Water Quality Criteria for 

acute and chronic toxicity. Concentrations of sulfate (SO4

), Al, 

Cd, Cu, Fe, and Zn decreased with distance from a site on Pike 

Hill Brook directly downstream from the mines (site 1) as a 

result of dilution and through sorption and precipitation of the 

trace metals. Significant statistical differences among the three 

continuously monitored sites were found for concentrations of 

SO4

, Ca, Cd, Cu, and Zn; however, instantaneous loads of Cd, 

Cu, and Zn at some of the three continuously monitored sites 

were statistically similar. Instantaneous loads of SO4

 also were 

statistically similar among the three sites.

Synoptic water-quality samples were collected for 

major ions and trace elements at 10 sites in November 2004, 

April 2005, and June 2005 and at 13 sites in August 2005 to 

describe the spatial and seasonal variability in the water quality of streams in and around the Pike Hill Brook watershed. 

Synoptic sites represented conditions in Pike Hill Brook, 

a tributary to Cookville Brook, the Waits River below the 

confluence with Pike Hill Brook, and background conditions. 

Concentrations of Al, Fe, Cd, Cu, and Zn at background sites 

generally were lower than those observed at other synoptic 

sites. Some concentrations of Al, Fe, Cd, Cu, and Zn were 

above acute and chronic toxicity standards at sites in Pike Hill 

Brook (sites 1, 3, 4, 5, 6, and 7). The concentration of Cu from 

one sample was above the chronic standard at a tributary to 

Cookville Brook (site 10). No concentrations of Al, Fe, Cd, 

Cu, or Zn were above toxicity standards at background sites 

(sites 2 and 8) or in the Waits River below the confluence with 

Pike Hill Brook (site 9).

Estimates of annual and seasonal loads at the three 

continuously monitored sites showed that loads of Cd and Zn 

in Pike Hill Brook directly below the mines (site 1) were about 

five times greater than at a site about 3 mi downstream (site 5), 

whereas the annual load for Cu at site 1 was about seventeen 

times greater than at site 5. The annual load for SO4

 was 

greater at site 5 than at site 1.

Wetlands can interact chemically with ARD through 

both aerobic and anaerobic pathways. Samples collected 

from Pike Hill Brook upstream and downstream from a series 

of wetlands during low flows in August 2005 showed that 

oxidation of ferrous Fe and precipitation of Fe-hydroxides 

were probably not affecting trace metals in the wetlands 

through sorption. A significant portion of the iron entering the 

wetlands was in particulate form, however, and may transport 

sorbed copper and other trace metals. Thus, aerobic activity 

in the wetlands probably is not affecting metal cycling in the 

watershed. Anaerobic bacterial sulfate reduction, however, 

may have affected loads of SO4

. Loads of Cu increased 

downstream from the wetlands and may reflect the reductive 

dissolution of ferric hydroxide particulates in anaerobic parts 

of the wetlands.

The most apparent effects on the macroinvertebrate 

assemblages caused by high levels of ARD were seen in the 

abundance of organisms and richness of taxa. A decrease in 

the macroinvertebrate abundance was strongly correlated to 

increasing values of the Hazard Index. This response was 

clearly indicated by the progressive decrease in Hazard Index 

with a concurrent increase in macroinvertebrate abundance 

among the Pike Hill Brook sites as the distance increased 

from the waste piles. In addition to a general decrease in taxa 

abundance with increasing ARD, a decrease in the richness 

of certain taxonomic groups also occurred. At the ARD 

sites, stoneflies were not quite as sensitive as the mayflies 

and the caddisflies. Neither mayflies nor caddisflies were 

present at site 1, and although downstream caddisfly richness 

increased steadily to site 5, mayflies were not present until a 

site about 2.5 mi downstream of site 1 (site 4A). In contrast, 

Chironomids as a group are typically regarded as relatively 

tolerant organisms, but their richness values were fairly well 

correlated with the Hazard Index, indicating that some midge 

taxa were sensitive to ARD. Results of this investigation will 

aid water-resources managers in determining what additional 

studies may be necessary for a remedial investigation and 

feasibility study for cleanup of the Pike Hill Superfund Site.

Summary and Conclusions 51
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for collecting benthic invertebrate samples as part of the 

National Water-Quality Assessment Program: U.S. Geological Survey Open-File Report 93–406, 66 p.

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water resources: New York, Elsevier Science Publishers, 

522 p.

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cleanup & reuse in New England, Pike Hill Mine, accessed 

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References Cited 53

Appendixes 1–2
Appendix 1.  Taxa and total number of macroinvertebrates for samples collected in the Pike Hill, VT, study area.—Continued

[Refer to figure 1 and table 1 for site names, station numbers, and locations. Cells with no values (blank) indicate no individuals of the taxon were collected at 

the site]

Taxa

Site number

1 2 3 4 4A 5 6 7 8 9 10

Ephemeroptera

Acentrella turbida 5 132 48

Baetis flavistriga 5 756 151 41

Baetis intercalaris 144 119

Baetis sp. 2 2 48 8 1

Epeorus sp. 72 24

Ephemera sp. 12

Ephemerella sp. 5 84 48

Heptageniidae 36 16

Isonychia sp. 71

Leptophlebiidae 8

Leucrocuta sp. 12 24

Paraleptophlebia sp. 12

Plauditus sp. 216 71

Procloeon sp. 1

Rhithrogena sp. 24

Stenonema sp. 156 40

Odonata

Boyeria grafiana 3 2 8

Boyeria sp. 1

Boyeria vinosa 2

Coenagrionidae 1

Cordulegaster sp. 6 5 3 7 2 5

Gomphidae 2 2 1 3 5

Ophiogomphus sp. 8

Plecoptera

Acroneuria abnormis 1 2 8

Agnetina capitata 1

Chloroperlidae 1 2

Leuctridae 7 1

Malirekus sp. 12 1

Paragnetina immarginata 7 56

Paragnetina sp. 1 53 12

Peltoperlidae 1

Perlidae 1

Perlodidae 3 1 1 26 4

Pteronarcys sp. 1 12 8

Soyedina sp. 33 7 1 2 1

Sweltsa sp. 1 7 2 3 35

Coleoptera

Anacaena sp. 1

Helichus sp. 5 1 4

Hydrobius sp. 2

Optioservus ovalis 58 7 25 2 156 5

56 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Appendix 1.  Taxa and total number of macroinvertebrates for samples collected in the Pike Hill, VT, study area.—Continued

[Refer to figure 1 and table 1 for site names, station numbers, and locations. Cells with no values (blank) indicate no individuals of the taxon were collected at 

the site]

Taxa

Site number

1 2 3 4 4A 5 6 7 8 9 10

Coleoptera—Continued

Optioservus sp. 63

Optioservus trivittatus 3

Oulimnius latiusculus 9 4 2 4 1

Promoresia tardella 2 1 6

Psephenus herricki 132 32

Stenelmis sp. 3 22 12 24

Megaloptera

Nigronia serricornis 7 12

Sialis sp. 3 1 1

Diptera-Chironomidae

Brillia sp. 4 2 2 3 1 7 12 6

Brundiniella sp. 4

Chaetocladius sp. 4

Chironomini 1 5

Cladotanytarsus sp. 12 24

Corynoneura sp. 5 26 12 16 1

Cricotopus bicinctus gr. 1 1 2 12

Cricotopus sp. 1 4 36

Cricotopus trifascia gr. 12

Diamesa sp. 1 12 1

Diplocladius sp. 7

Eukiefferiella brehmi gr. 8

Eukiefferiella claripennis gr. 10

Eukiefferiella coerulescens gr. 1 24

Heleniella sp. 23

Heterotrissocladius marcidus gr. 2

Krenopelopia sp. 2

Limnophyes sp. 20 14 1 7 1 10 12 4

Micropsectra sp. 4 1 1 3 24 16

Microtendipes pedellus gr. 12 40

Microtendipes rydalensis gr. 12 2 36

Nanocladius sp. 8

Orthocladius (Symp.) lignicola 2 1 1 12

Orthocladius Complex 2 1 5 24 4

Orthocladius sp. 8

Pagastia sp. 24

Parachaetocladius sp. 7

Parakiefferiella sp. 5

Parametriocnemus sp. 2 8 27 22 48 8

Paraphaenocladius sp. 2 2

Pentaneurini 1

Phaenopsectra sp. 1

Polypedilum aviceps 2 348 135

Appendix 1 57
Appendix 1.  Taxa and total number of macroinvertebrates for samples collected in the Pike Hill, VT, study area.—Continued

[Refer to figure 1 and table 1 for site names, station numbers, and locations. Cells with no values (blank) indicate no individuals of the taxon were collected at 

the site]

Taxa

Site number

1 2 3 4 4A 5 6 7 8 9 10

Diptera-Chironomidae—Continued

Polypedilum illinoense gr. 1

Polypedilum sp. 1 36 16

Polypedilum tritum 5 6 12 6

Potthastia gaedii gr. 97 2 10

Procladius sp. 1

Psilometriocnemus sp. 16

Rheocricotopus sp. 12 1 1

Rheotanytarsus exiguus gr. 1 12 24

Rheotanytarsus pellucidus gr. 2 144 16

Stempellinella sp. 24 8

Stenochironomus sp. 2 2 2 6

Stilocladius sp. 2

Sublettea sp. 12

Tanytarsus sp. 7 36

Thienemanniella sp. 5 36 16 1

Thienemannimyia gr. sp. 1 6 19 2 24 8

Tribelos jucundum 2

Tvetenia bavarica gr. 14 1 7 1 302 72

Tvetenia discoloripes gr. 8

Diptera - non Chironomidae

Antocha sp. 2 24

Atrichopogon sp. 1

Bezzia/Palpomyia sp. 84 2 3 12 15 2 32 17

Cryptolabis sp. 1

Culicidae 2

Dasyhelea sp. 6

Dicranota sp. 11 1 2 1

Diptera 1

Dixidae 1 1

Empididae 5

Hemerodromia sp. 3 17 12

Hexatoma sp. 35 6 1 1 4 2 36 32

Limonia sp. 2

Molophilus sp. 12 2 1

Neoplasta sp. 3

Pedicia sp. 7 1

Simulium sp. 6 6 5 24 8 3

Stilobezzia sp. 23 1

Tabanidae 1 1

Tipula sp. 2 1 10 1

Tipulidae 2 6 1 12 3

Wiedemannia sp. 7 1 1 22 8 3

58 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Appendix 1.  Taxa and total number of macroinvertebrates for samples collected in the Pike Hill, VT, study area.—Continued

[Refer to figure 1 and table 1 for site names, station numbers, and locations. Cells with no values (blank) indicate no individuals of the taxon were collected at 

the site]

Taxa

Site number

1 2 3 4 4A 5 6 7 8 9 10

Trichoptera

Brachycentrus appalachia 2 24 63

Ceraclea sp. 24

Cheumatopsyche sp. 1 21 84 143 1

Chimarra aterrima 4 6 151

Diplectrona sp. 2 3 1 2 1 6 7 7

Dolophilodes sp. 28 12 8

Glossosoma sp. 24

Glossosomatidae 2 127

Helicopsyche borealis 300 975

Hydropsyche betteni 11 66

Hydropsyche bronta 8

Hydropsyche morosa 84 95

Hydropsyche morosa gr. 28 1 8

Hydropsyche slossonae 74

Hydropsyche ventura 26 13

Lepidostoma sp. 2 216 56 31

Limnephilidae 23 1 1 1

Mystacides sp. 1 10 12

Neophylax sp. 24

Oecetis avara 8

Oxyethira sp. 1 1

Parapsyche apicalis 3 2

Parapsyche sp. 21 2

Philopotamidae 2

Phryganeidae 1 1

Polycentropus sp. 1 5 24

Psilotreta sp. 1 12

Ptilostomis sp. 1 1

Rhyacophila acutiloba 5

Rhyacophila atrata 1

Rhyacophila fuscula 1 7 8 3

Rhyacophila invaria gr. 28 8

Rhyacophila minora 9

Rhyacophila sp. 1 1 8 2

Setodes sp. 84 16

Lepidoptera

Lepidoptera 2 8 3

Pyralidae 1

Gastropoda

Lymnaeidae 24 16

Physa (Physella) sp. 1 12

Bivalvia

Sphaeriidae 2

Appendix 1 59
Appendix 1.  Taxa and total number of macroinvertebrates for samples collected in the Pike Hill, VT, study area.—Continued

[Refer to figure 1 and table 1 for site names, station numbers, and locations. Cells with no values (blank) indicate no individuals of the taxon were collected at 

the site]

Taxa

Site number

1 2 3 4 4A 5 6 7 8 9 10

Annelida

Oligochaeta 21 4 1 7 3 19 132 16 20

Acari

Acari 8

Atractides sp. 12

Hygrobates sp. 2

Lebertia sp. 2 1 4 2 2

Oribatei 9 1 7 2 3 3 17 12 8 4

Panisus sp. 2 2 1

Protzia sp. 12

Sperchon sp. 2 5 12

Crustacea

Hyalella sp. 6

Other

Nematoda 25 2 1 9 1 2 24 3

Turbellaria 2 1

Total abundance 30 539 42 152 155 198 504 814 4,262 2,855 289

Taxa richness 6 49 17 31 24 55 51 52 65 57 47

60 Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005
Appendix 2.  Vermont Department of Environmental Conservation (VT-DEC) bioassessment metrics for macroinvertebrate

assemblages.

[The evaluation that is the basis for figure 28 used metrics 1–5 because they appeared to be more responsive to acid rock drainage, whereas metrics 6–8 appear 

to generally be more representative to changes in organic pollution]

1. Density - The relative abundance of invertebrates in a sample.

2. Richness - The number of taxa in a sample.

3. EPT Index - A subset of the richness measure, it is the number of taxa in the generally more environmentally sensitive orders of 

Ephemeroptera, Plecoptera, and Trichoptera.

4. Percent Model Affinity of Orders - (PMA-O) - A measure of order-level similarity that is based on finding the percentage composition 

for each major order in the sample and comparing these values to the percentage values for an appropriate reference stream. 

5. Pinkham-Pearson Coefficient of Similarity - Functional Groups - (PPCS-F) - A measure of functional-feeding group similarity to 

a model based on an appropriate reference stream. It is similar in concept to the PMA-O in that a site is compared to a model of the 

composition of the functional feeding groups.

6. EPT/EPT & Chironomidae - A measure of the ratio of the abundance of the intolerant EPT orders to the generally tolerant Diptera 

family Chironomidae.

7. Percent Oligochaeta - A measure of the percent of the macroinvertebrate community made up of the Oligochaeta.

8. Hilsenhoff Biotic Index - HBI (0–10) - A measure of the macroinvertebrate assemblage tolerance toward organic (nutrient) enrichment. 

The HBI is metric that is an indicator of sensitive taxa as well as functional groups, because taxa that become more dominant in moderately enriched streams are usually responding to changes in the available food base.

Appendix 2 61
Prepared by Publications Service Center 1

For more information concerning the research in this report, contact:

Keith W. Robinson, Director

U.S. Geological Survey

New Hampshire-Vermont Water Science Center

361 Commerce Way

Pembroke, NH 03275

or visit our Web site at:

http://nh.water.usgs.gov
Kiah, Richard G., and others—Surface-Water Hydrology and Quality at the Pike Hill Superfund Site, Corinth, Vermont, October 2004 to December 2005— 

Scientific Investigations Report 2007–5003