Effect of On-Site Wastewater Disposal on Quality of 

Ground Water and Base Flow—

A Pilot Study in Chester County, Southeastern Pennsylvania, 2005

By Lisa A. Senior and Peter J. Cinotto

In cooperation with the 

Chester County Water Resources Authority and 

Chester County Health Department 

Open-File Report 2007-1253

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. Meyers, Director

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

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

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

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

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report.

Suggested citation:

Senior, L.A., and Cinotto, P.J., 2007, Effect of on-site wastewater disposal on quality of ground water and base flow—

A pilot study in Chester County, southeastern Pennsylvania, 2005: U.S. Geological Survey Open-File Report 2007-1253,

50 p.
iii

Contents

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

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

Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

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

Hydrogeologic Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Land Use and Wastewater Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Previous Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Study Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Selection of Sampling Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Collection of Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Analysis of Samples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Ground-Water and Base-Flow Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

Inorganic Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

General Water Quality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Nitrate and Other Nutrients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Chloride . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Boron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Organic Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

Bacteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Seasonal Base-Flow Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Effects of On-Site Wastewater Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Comparison to Results from Previous Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Figures

1-3. Maps showing: 

1. Location of the Broad Run watershed, central Chester County, southeastern 

Pennsylvania. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

2. Bedrock geology in and near the Broad Run watershed, Chester County, 

Pennsylvania. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

3. Land use and location of streamflow-measurement station 01480638, observation 

well CH-12, and 2005 ground-water and base-flow sampling sites in and near 

the Broad Run watershed, Chester County, Pennsylvania . . . . . . . . . . . . . . . . . . . . . . .5

4. Graph showing streamflow at streamflow-measurement station 01480638, Broad Run 

at Northbrook, Pa., in 2005 and periods of base-flow and ground-water sample collection. . .6

5. Conceptual schematic showing predominant land use in tributaries selected for 

sampling in the Broad Run watershed, Chester County, Pennsylvania . . . . . . . . . . . . . . . . . .7

6. Map showing location of stream sites and specific conductance and stream 

temperature measured during field survey in and near Broad Run watershed, 

Chester County, Pa., May 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

7-16. Graphs showing: 

7. Nitrate concentrations in ground-water and base-flow samples in areas 

of different land uses in and near the Broad Run watershed, Chester 

County, Pa., May-June 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
iv

8. Chloride concentrations in ground-water and base-flow samples in areas 

of different land uses in and near the Broad Run watershed, Chester 

County, Pa., May-June 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

9. Sodium and chloride concentrations in ground-water and base-flow 

samples in areas of different land uses in and near the Broad Run watershed, 

Chester County, Pa., May-June 2005. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

10. Boron concentrations in ground-water and base-flow samples in areas 

of different land uses in and near the Broad Run watershed, Chester 

County, Pa., May-June 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

11. Number of wastewater compounds detected in ground-water and base-flow 

samples in areas of different land uses in and near the Broad Run watershed, 

Chester County, Pa., May-June 2005. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

12. Bacteria concentrations in ground-water and base-flow samples in areas of 

different land uses in and near the Broad Run watershed, Chester County, Pa., 

May-June 2005. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

13. Base flow in areas of different land uses in and near the Broad Run watershed, 

Chester County, Pa., in May and September 2005. . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

14. Boron concentrations in base flow in areas of different land uses in and near the 

Broad Run watershed, Chester County, Pa., in May and September 2005. . . . . . . . . . .25

15. Concentrations of (A) enterococci and (B) fecal coliform bacteria in base flow in 

areas of different land uses in and near the Broad Run watershed, Chester County, 

Pa., in May and September 2005. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

16. Number of organic wastewater compounds detected in base flow in 

areas of different land uses in and near the Broad Run watershed, Chester County, 

Pa., in May-June and September 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Tables

1. Description of stream sites where base-flow samples were collected in and near 

the Broad Run watershed, Chester County, Pa., May-June and September 2005. . . . . . . . . .9

2. Description of ground-water sites where samples were collected in and near the 

Broad Run watershed, Chester County, Pa., June 2005. . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

3. Concentrations of chloride, boron, and nitrate in ground-water and base-flow samples 

collected May-June 2005 in and near the Broad Run watershed, Chester County, 

Pa., listed by land use for each tributary drainage area. . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

4. Reported minimum, maximum, and average concentrations of selected constituents 

in septic-tank effluent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

5. Organic wastewater compounds detected in samples from 10 surface-water 

and 10 ground-water sites, May-June and September 2005, Broad Run watershed and 

vicinity, Chester County, Pa., listed in order of the number of surface-water sites 

with detections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

6. Results of laboratory analysis for nitrate, chloride, boron, and selected wastewater 

compounds in samples collected from 12 wells in summer 2000 or summer 2002 in 

areas possibly affected by on-site wastewater disposal, Chester County, Pennsylvania . . .31

7. Results of laboratory analysis of base-flow samples collected in and near the Broad 

Run watershed, Chester County, Pennsylvania, May-June and September 2005. . . . . . . . .35

8. Results of laboratory analysis of ground-water samples collected in and near the 

Broad Run watershed, Chester County, Pennsylvania, June 2005. . . . . . . . . . . . . . . . . . . . .45
v

Conversion Factors and Datum Conversion Factors and 

Datum

Multiply By To obtain

Length

inches (in.)

foot (ft)

mile (mi)

25.4

 0.3048

 1.609

millimeter (mm)

meter (m)

kilometer (km)

Area

acre

acre

square mile (mi2)

square mile (mi2)

4,047

0.4047

259.0

 2.590

square meter (m2

)

hectare (ha)

hectare (ha)

square kilometer (km2)

Mass

microgram

milligram

gram (g)

kilogram (kg)

35,270

352.7

0.03527

2.205

ounce, avoirdupois (oz)

ounce, avoirdupois (oz)

ounce, avoirdupois (oz)

pound avoirdupois (lb)

Temperature is given in degrees Celsius (°C) which may be converted to degrees Fahrenheit (°F) 

as follows:

°F = (1.8 x °C) + 32.

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

°C = (°F - 32) / 1.8

Vertical coordinate information is referenced to the National Geodetic Datum of 1929 (NVGD 29).

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

Altitude, as used in this report, refers to distance above the vertical datum.

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

25°C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or 

micrograms per liter (μg/L), which are approximately equivalent to parts per million (ppm) or 

parts per billion (ppb), respectively.

Concentrations of bacteria in water are given in colonies per 100 milliliters (col/100 mL), which is 

the same as colony forming units per 100 milliliters (CFU/100 mL).

Effect of On-Site Wastewater Disposal on Quality of Ground Water 

and Base Flow—A Pilot Study in Chester County, Southeastern 

Pennsylvania, 2005

by Lisa A. Senior and Peter J. Cinotto

Abstract

On-site wastewater disposal has the potential to introduce 

contaminants into ground water and subsequently, by groundwater discharge, to streams. A pilot study was conducted during 

2005 by the U.S. Geological Survey in cooperation with the 

Chester County Health Department and the Chester County 

Water Resources Authority to determine if wastewater components, including inorganic constituents and selected organic 

wastewater compounds, such as detergents, considered to be 

emerging contaminants, were present in ground water and 

stream base flow in areas with on-site wastewater disposal. The 

study area was a small watershed (about 7.1 square miles) of 

mixed land use drained by Broad Run in central Chester 

County, Pa. The area is underlain by fractured metamorphic 

rocks that form aquifers recharged by precipitation. Surfaceand ground-water sampling was done in areas with and without 

on-site wastewater disposal for comparison, including a relatively densely populated village with cesspools and septic systems, a residential area with septic systems, a residential area 

served by sewers, and agricultural land. Samples were collected 

in May-June and September 2005 from eight headwater stream 

sites under base-flow conditions and in June 2005 from eight 

wells and two springs. Samples were analyzed for major ions, 

nutrients, boron, bacteria, and a suite of organic wastewater 

compounds. Several emerging contaminant wastewater compounds, including detergent components, insect repellents, and 

flame retardants, were detected in base-flow and ground-water 

samples. Stream base-flow samples generally contained more 

compounds and higher concentrations of those compounds than 

did ground-water samples, and of the ground-water samples, 

samples from springs contained more compounds and higher 

concentrations than samples from wells. Concentrations of 

nitrate, chloride, and boron (inorganic constituents associated 

with wastewater) generally were all elevated in base-flow and 

ground-water samples in areas with relatively high densities of 

on-site wastewater disposal (septic systems or cesspools) compared to other areas sampled. Results of this pilot study should 

be considered preliminary because of limited data. 

Introduction

On-site wastewater disposal has the potential to introduce 

contaminants into ground water and subsequently, by groundwater discharge, to streams. In many rural to semi-rural areas, 

wastewater disposal through on-site systems is common. In 

these areas, water supply usually is from on-site wells or 

springs. Thus, the potential contamination of ground water by 

on-site wastewater disposal may affect those that use ground 

water for supply and also the quality of base flow (ground-water 

discharge to streams).

In Chester County, Pa., and other rural areas undergoing 

development, the change in land use consists of residential and 

commercial uses replacing forested or agricultural uses. In 

many of the areas being developed, residential wastewater is 

disposed of on-site rather than through sewers to a regional 

wastewater treatment plant. On-site disposal methods historically have included both septic systems and cesspools for individual residences. Cesspools are no longer permitted in Chester 

County and most cesspools have been removed from operation. 

In 2005, a pilot study of the effect of residential on-site wastewater disposal on ground-water and base-flow water quality 

was conducted by the U.S. Geological Survey (USGS), in cooperation with the Chester County Water Resources Authority and 

Chester County Health Department, to provide reconnaissance 

data that may assist in management of water resources in the 

county.

Purpose and Scope

This report presents and discusses the data collected for a 

pilot study of the effect of on-site wastewater disposal on 

ground-water and base-flow water quality in and near a small 

watershed in central Chester County, Pa., from May to September 2005. Ground-water and base-flow samples were collected 

in areas predominantly covered by a single land use and with 

different types of wastewater disposal, including areas with onsite disposal (septic systems and cesspools) and off-site disposal (area sewered). Base-flow samples were collected at 10 

headwater stream sites in May 2005, and at 8 of those 10 sites 

in September 2005, representing different hydrologic condi-
2 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

tions. Ground-water samples were collected from eight wells 

and two springs in June 2005. Water samples were analyzed for 

major ions, selected trace elements, nutrients, bacteria, and a 

suite of organic wastewater compounds considered to be 

emerging contaminants. Ground-water and base-flow water 

quality in the areas with different land uses are described. 

Nitrate, chloride, boron, and organic wastewater compounds 

were considered indicators of wastewater in the ground water 

and base flow. Differences and similarities in base-flow water 

quality in spring and fall 2005 are discussed.

Description of Study Area

The study area is approximately bounded by the 7.08 mi2

Broad Run watershed, a tributary to West Branch Brandywine 

Creek in central Chester County, Pa. (fig. 1). The area is in the 

Piedmont Physiographic Province, southeastern Pennsylvania. 

The topography is characterized by rolling hills. The area has a 

humid temperate climate and receives an average total annual 

precipitation of about 48 in. [30-year normal (1971-2000) for 

meteorological station West Chester 2 NW about 8 mi east of 

the study area is 47.89 in.] (National Oceanic and Atmospheric 

Administration, 2005a), which is distributed nearly evenly 

throughout the year. 

BROAD RUN WATERSHED

COUNTY BOUNDARY

EXPLANATION

0 10 20 30 MILES

0 10 20 30 KILOMETERS

39 45’

40 

76 

75 45’

75 30’

STATE BOUNDARY

PENNSYLVANIA

LOCATION OF STUDY AREA

COATESVILLE

HONEYBROOK

DOWNINGTOWN

WEST CHESTER

BRANDYWINE CREEK BASIN

West Branch Brandywine Creek

East Branch Brandywine Creek

Figure 1. Location of the Broad Run watershed, central Chester County, southeastern Pennsylvania.
Study Methods 3

Hydrogeologic Setting

The area is underlain by Paleozoic and older metamorphic 

rocks, including phyllite, schist, marble, and gneiss (fig. 2). A 

more complete description of the geologic units in the study 

area is given by Cinotto and others (2005). The competent bedrock is overlain by weathered bedrock (saprolite) and soil. 

Thickness of the saprolite varies but commonly is 10 to 40 ft. 

Soils in most of the area are moderately deep and well drained 

(Cinotto and others, 2005).

The bedrock and overlying saprolite form an unconfined 

aquifer recharged by precipitation. Recharge infiltrates through 

soils and saprolite to bedrock and flows through fracture openings in the bedrock and also in the saturated part of the saprolite. 

Under natural conditions, ground water discharges to streams 

and springs. The water table generally is a subdued replica of 

the land surface, as shown by a map of ground-water levels in 

the area (Garges, 1988), such that ground-water flowpaths commonly follow topography. Base flow (supplied by ground-water 

discharge to streams) comprises about 82 percent of total annual 

streamflow in the Broad Run watershed (Cinotto and others, 

2005, p. 21).

Depth to water typically varies by topography; depths to 

water are greater under hilltops than on slopes or in valleys. In 

a 2003-04 study of the Broad Run watershed, the depth to water 

in 14 wells ranged from less than 1 ft below land surface (bls) 

in the stream valley to about 86 ft bls below a hilltop; the magnitude of annual water-level fluctuations in these wells also differed by topographic setting, ranging from about 1 ft in the valley to about 10 ft under a hilltop. Ground-water levels fluctuate 

seasonally because of changes in net recharge rates; depth to 

water is greatest in the fall and least in the spring. Although precipitation is distributed nearly evenly throughout the year, net 

recharge generally is greater in the cooler months (OctoberApril), when evapotranspiration is reduced, than in the warmer 

months (May-September). Long-term average ground-water 

levels and base flow are highest in spring and lowest in fall in 

Chester County, Pa.

Drilled wells generally are completed as open holes in the 

bedrock, with casing extending through the saprolite to the top 

of competent bedrock. Hand-dug wells generally are completed 

in the saprolite. 

Land Use and Wastewater Disposal

Land use in the study area is mixed (fig. 3), consisting of 

agricultural (33 percent), wooded (29 percent), residential 

(27 percent), recreational (golf course) (8 percent), and other 

uses (schools, utilities, water) (about 3 percent) in the Broad 

Run watershed (Cinotto and others, 2005, p. 4). Agricultural 

products and uses include row crops, orchards, hay, and dairy 

cow and horse pasture. Residential areas can be characterized as 

relatively dense village (Marshallton), suburban (lot size of 1 to 

2 acres or smaller), or rural suburban (lot size greater than 

2 acres). The village of Marshallton has been settled since at 

least 1760. Most of the suburban residential development has 

occurred since 1970.

Wastewater disposal in most of the residential areas during 

the period of study (2005) was through on-site systems, largely 

consisting of septic systems but also including some cesspools 

in the village of Marshallton. In the northern part of the study 

area, a public wastewater system operated by the Utilities Inc. 

of Pennsylvania serves residential areas and there is little to no 

on-site wastewater disposal. Wastewater in this sewered area is 

exported out of the watershed, treated at the Broad Run sewer 

plant, and discharged to the East Branch Brandywine Creek. 

There is no in-stream discharge of treated wastewater within the 

study area. A municipal wastewater collection and land application system was under construction for some portions of the 

study area and that system has been in operation since the completion of this study. 

Previous Studies

Data on stream-water quality in the Broad Run watershed 

were collected during recent studies by Senior and Koerkle 

(2003a; 2003b) and Cinotto and others (2005). Ground-waterquality data in areas with on-site wastewater disposal have been 

collected by USGS in cooperation with the Chester County 

Water Resources Authority and Chester County Health Department since 2000 as part of an ongoing Chester County groundwater-quality monitoring program. These data included analyses for emerging contaminant organic wastewater compounds 

such as detergent metabolites, selected antibiotics, hormones, 

and others, as well as analyses for inorganic constituents that 

are wastewater indicators such as nitrate, ammonia, chloride, 

and boron. Most of the data have been published (Durlin and 

Schaffstall, 2001, p. 429-433; 2003, p. 512-515), but some of 

the data on emerging contaminants collected in 2000 and on 

antibiotics collected in 2002 have not been published prior to 

this report. 

Study Methods

Stream samples under base-flow conditions were collected 

twice and ground-water samples were collected once in the 

period from May to September 2005 to provide reconnaissancelevel data for the pilot study (fig. 4). Data were collected for a 

preliminary assessment of potential effects of on-site wastewater disposal on ground-water and base-flow water quality and 

were not intended to support statistical analyses. The assessment was done by describing results and comparing results 

within this study to other studies. Because of limited data and 

lack of statistical analysis to evaluate differences in water quality among land uses, conclusions should be considered preliminary and results should be interpreted with caution. Comparisons of concentrations in samples from various land uses were 

not tested statistically and are presented as being higher or 

lower in a relative sense. 
01480913 01480637 014806374 014806394 014806384 014806369 014806368 014806366 0148063522 0148063532 7556883 SP71 SP70 6882 6881 6879 6880 6878 6673 12 12 01480913 6881 75°45' 75°43'30" 75°42' 75°40'30"

39°55'30"

39°57'

39°58'30"

0 1 2 MILES

0 1 2 KILOMETERS

EXPLANATGEOLOGIC F

Coc

Oct

Pete

Wis

Dia

Fels

Peg

Ultr

Felsamp

Bro

Stre

Obs

StreGrospri

Geology from Sloto, 1994

West Branch Brandywine Creek

East Branch Brandywine Creek

Marshallton

Figure 2. Bedrock geology in and near the Broad Run watershed, Chester County, Pennsylvania.Location of wells and stream sites sampled in 2005 and long-term observation well CH-12 also are shown.
01480913

01480637

014806374

014806394

014806384

014806369

014806368

014806366

0148063522

0148063532

755

6883

SP71

SP70 6882

6881

6879

6880

6878

6673

12

01480638

12

6881

01480913

01480638

75°45' 75°43'30" 75°42' 75°40'30"

39°55'30"

39°57'

39°58'30"

0 1 2 MILES

0 1 2 KILOMETERS

EXPLANATILAND USE

Agric

Comm

InstitMultiPubli

Singl

TransVacaWateWoo

Sewe

Broa

Strea

Streaand sObseStreaGrousprin

Land use from Delaware Valley Regional Planning Commission, 2004

ROUTE 162

ROUTE 162

ROUTE 322

STRASBURG ROAD

Figure 3. Land use in 2000 and location of streamflow-measurement station 01480638, observation well CH-12, and 2005 ground-water and base-flow 

near the Broad Run watershed, Chester County, Pennsylvania. 
6 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

The sampling times were selected to collect stream samples under high base-flow (May-June 2005) and low base-flow 

(September 2005) conditions to determine if water quality was 

affected by hydrologic conditions. The ground-water samples 

were collected in mid-June 2005 to approximately represent 

ground-water quality at the time of the late May base-flow sampling. Streamflow in May and September 2005 in the study area 

was probably below average for those months. Long-term averages are not available for Broad Run because the streamflow 

record only began in 2003, but estimates can be made using 

streamflow data for nearby unregulated streams. Using longterm (1960-2005) data at streamflow-measurement station 

01480300, West Branch Brandywine Creek near Honeybrook, 

Pa., a site with a relatively small drainage area (18.7 mi2), May 

2005 streamflow was about 27 percent below average and September 2005 streamflow was about 66 percent below average 

(Durlin and others, 2006). Ground-water levels in a nearby 

observation well CH-12 (Durlin and others, 2006) were slightly 

higher in June 2005 than the long-term median for that month 

and slightly lower in September 2005 than the long-term 

median for that month. Descriptions of the sampling locations 

and procedures for collecting and analyzing samples follow.

O N D J F AM M N J J A S O D

1,000

100

10

1

STREAMFLOW, IN CUBIC FEET PER SECOND

MAY 

BASE-FLOW

SAMPLING

JUNE

GROUND-WATER

SAMPLING

SEPTEMBER

BASE-FLOW

SAMPLING

2004 2005

Figure 4. Streamflow at streamflow-measurement station 01480638, Broad Run at Northbrook, Pa., in 2005 and 

periods of base-flow and ground-water sample collection
Study Methods 7

Selection of Sampling Locations

Land use in headwater areas of some tributaries to Broad 

Run is relatively homogenous (fig. 3). Because recharge and 

discharge are local in the headwater areas, ground water and 

base flow in tributary subbasins might be expected to show the 

effects of those specific land uses. Sampling locations were 

selected to characterize ground-water and base-flow water quality in drainage areas of each land use. A conceptual schematic 

of land use in areas drained by tributaries selected for sampling 

is shown in fig. 5. Sites were selected for the following land-use 

areas: agricultural (minimal human on-site wastewater disposal), residential area with sewers, residential area with moderate density on-site wastewater disposal (septic systems), and 

residential area with high-density on-site wastewater disposal 

(cesspools and septic systems). Locations of the 10 stream sites 

and 10 ground-water sites sampled are shown in figs. 2 and 3. 

Prior to finalizing the location of stream-sampling sites, a 

field survey of stream temperature and specific conductance 

was completed in mid-May 2005 in tributaries within the Broad 

Run watershed to locate areas of ground-water discharge (on 

the basis of temperature) and to identify areas of different water 

quality (on the basis of specific conductance) (fig. 6). Stream 

temperatures ranged from 11.5 to 15.9 degrees Celsius, up to 

10 degrees Celsius cooler than the average air temperature 

(23 degrees Celsius) in the week prior to the survey, as reported 

at the meteorological station in West Chester (West Chester 2 

NW) by the National Oceanic and Atmospheric Administration 

(2005b); stream temperatures similar to ground-water temperature (about 12 degrees Celsius) indicate nearby ground-water 

discharge to the streams. In these small streams, water temperatures can be raised rapidly by exposure to sun and warm air. 

The specific conductance, a measure of dissolved constituents, 

ranged from 114 to 368 μS/cm. One of the stream sites 

(014806374, fig. 3) selected during the survey for sampling was 

a seep from a hillside in an agricultural area undergoing new 

land development, was near a suspected leaking sewer, and had 

the highest specific conductance of 368 μS/cm. This site is not 

discussed at length later in the report because it is unlike the 

other headwater stream sites selected for sampling, and sampling results indicate little or no water-quality problems there. 

RESIDENTIAL - SEWERED

RESIDENTIAL - MODERATE-DENSITY ON-SITE 

WASTEWATER DISPOSAL (SEPTIC SYSTEMS)

RESIDENTIAL - HIGH-DENSITY ON-SITE

WASTEWATER DISPOSAL (CESSPOOLS

AND SEPTIC SYSTEMS) AGRICULTURAL

Figure 5. Conceptual schematic showing predominant land use in tributaries selected for sampling in the Broad Run 

watershed, Chester County, Pennsylvania. 
194 13 196 13 174 12 188 12 146 13.8 180 13.1 253 13.2

16515.2

163

14.8

16915.9

12914.8

25015.1

24514.5

21713.4

14313.5

17215.1 146

13.9

36813.3

24515.2

12111.8

11413.3

341

11.9

17511.5

19912.1

16915.9

75°45' 75°43'30" 75°42' 75°40'30"

39°55'30"

39°57'

39°58'30"

0 1 2 MILES

0 1 2 KILOMETERS

EXPLANAT

Broa

Stre

Streis st(in mand temp

West Branch Brandywine Creek

East Branch Brandywine Creek

Figure 6. Location of stream sites and specific conductance and stream temperature measured during field survey in and near Broad Run watersheMay 2005.
Study Methods 9

Base-flow samples were collected at 10 stream sites in 

May-June 2005 and at 8 of the 10 sites in September 2005. 

Originally, all 10 stream sites were sampled in May but 3 had to 

be resampled for wastewater compound analysis in June 2005 

because of laboratory problems with the original samples. Two 

of the 10 stream sites could not be re-sampled in September 

2005 because there was no flow (site 0148063522 and 

014806374, fig. 3); 1 (site 014806374) of the 2 stream sites that 

went dry was from a hillside seep discussed above. Groundwater samples were collected from eight wells and two springs 

(fig. 3) in June 2005. Depths to water ranged from about 18 to 

64 ft bls in six wells in which water levels were measured. The 

depth to water measured in well CH-6673 in June 2005 was 30 

to 40 ft greater than had previously been measured in the well, 

suggesting that the well may have been pumped recently prior 

to the time of water-level measurement. Well depths ranged 

from 92 to 430 ft in four wells with construction information. 

Some differences in ground-water quality may be related to different depths and flow paths of ground water supplying wells 

and springs, which are unknown or little known in the study 

area. Descriptions of the stream sites and well characteristics 

are given in tables 1 and 2. 

Table 1. Description of stream sites where base-flow samples were collected in and near the Broad Run watershed, Chester County, 

Pa., May-June and September 2005.

[mi2, square miles; NAD 27, North American Datum of 1927; DDMMSS, degrees, minutes, seconds; --, no data]

U.S. Location 

Geological Drainage (NAD 27) Predominant land use in 

Survey site Site name area drainage area 

identification (mi2

) Latitude Longitude (type of wastewater disposal)

number (DDMMSS) (DDMMSS)

0148063522 Unnamed tributary to Broad Run above 0.24 39°58’21” 75°44’15” Residential (sewer)

school near Thorndale, Pa.

0148063532 Unnamed tributary to Broad Run at Chest- .27 39°58’02” 75°44’53” Agricultural (on-site wastewater disnut Lane near Thorndale, Pa. posal)1

014806366 Little Broad Run above Shadyside Road .11 39°58’02” 75°42’58” Residential (on-site wastewater disposal)

near Romansville, Pa.

014806368 Unnamed tributary to Little Broad Run .21 39°57’51” 75°43’04” Residential (on-site wastewater disposal) 

near Romansville, Pa. and some agricultural

014806369 Little Broad Run below Shadyside Road .49 39°57’50” 75°42’54” Residential (on-site wastewater disposal)

near Romansville, Pa.

01480637 Little Broad Run near Marshallton, Pa. .60 39°57’38” 75°42’44” Residential (on-site wastewater disposal)

014806374 Outfall tributary to Broad Run above Rt. -- 39°56’59” 75°42’21” Agricultural (possible leaking sewer?)

162 near Marshallton, Pa.

014806384 Unnamed tributary to Broad Run at Mar- .05 39°56’47” 75°41’07” Residential (high density on-site 

shallton, Pa. wastewater disposal-septic systems and 

cesspools)

014806394 Unnamed tributary to West Br. Brandy- .16 39°56’38” 75°40’30” Residential (high density on-site 

wine Cr. at Marshallton, Pa. wastewater disposal-septic systems and 

cesspools)

01480913 Unnamed tributary to East Br. Brandy- .06 39°57’19” 75°40’58” Residential (high density on-site 

wine Cr. at Marshallton, Pa. wastewater disposal-septic systems and 

cesspools) and wooded

1

In sewer-service area.
10 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Collection of Samples

Samples were collected and processed using standard 

methods (U.S. Geological Survey, variously dated). Samples of 

base flow were collected as grab samples because the streams 

were small (less than 5 ft in width) and shallow (less than 0.6 ft 

in depth) with low flows (less than 1 ft3

/s). These small streams 

were assumed to be well mixed. Streamflow at the time of baseflow sample collection was measured using a current meter or a 

flume if flow was too small to be measured with a current meter. 

Ground-water samples were collected from wells using existing 

pumps and plumbing but bypassing any treatment systems. 

Water levels in the wells were measured prior to pumping, and 

wells were pumped until field constituents (pH, temperature, 

specific conductance, and concentration of dissolved oxygen) 

stabilized before sample collection. For the two springs, samples were collected using a peristaltic pump immersed in the 

spring pool. 

Samples for dissolved-constituent analysis were filtered in 

the field using a 0.45 micron capsule filter. Samples for dissolved major ions and trace elements were preserved using 

nitric acid. Samples for analysis of organic wastewater compounds were unfiltered and collected directly in baked glass 

bottles from the stream or well head; these samples were subsequently filtered through a baked glass fiber filter at the laboratory before analysis. Whole-water samples for bacteriological 

analysis were collected in plastic bottles provided by the Chester County Health Department. As necessary, samples were 

chilled after collection and during shipment to the laboratory.

Three of the 10 base-flow sites sampled in May 2005 were 

re-sampled in June 2005 for organic wastewater compounds 

because the May 2005 samples from these sites were adversely 

impacted at the laboratory and could not be analyzed. The three 

affected samples were from sites 014806368, 014806369, and 

01480637 (fig. 3; table 7 at the back of the report).

Table 2. Description of ground-water sites where samples were collected in and near the Broad Run watershed, Chester County, Pa., June 

2005.

[NAD 27, North American Datum of 1927; DDMMSS, degrees, minutes, seconds; ft, feet; NGVD, National Geodetic Vertical Datum of 1929; ft bls, feet below land 

surface; --, no data; na, not applicable]

Location (NAD 27) Most U.S. Land- recent Geological U.S. Geological surface Date Well Depth to date of Survey Survey site elevation well Predominant land use in drainage depth water water- local well identification Latitude Longitude (ft above drilled area (type of wastewater disposal) (ft) (ft bls) level or spring number (DDMMSS) (DDMMSS) NGVD (year) measure- number 1929) ment

CH-755 395651075405601 39°56’52” 75°40’55” 390 92 1940 57.3 10/25/1963 Residential (high-density on-site 

wastewater disposal-septic systems 

and cesspools)

CH-6673 395735075425301 39°57’35” 75°42’54” 369 430 1990 1

62.95 6/1/2005 Residential (on-site wastewater disposal)

CH-6878 395654075405001 39°56’54” 75°40’51” 395 -- -- -- -- Residential (high density on-site 

wastewater disposal-septic systems 

and cesspools)

CH-6879 395752075424801 39°57’52” 75°42’49” 398 128 1958 41.34 6/2/2005 Residential (on-site wastewater disposal)

CH-6880 395815075435501 39°58’14” 75°43’56” 557 -- -- 38.25 6/2/2005 Residential (sewer)

CH-6881 395701075404401 39°57’00” 75°40’45” 405 150 -- 24.03 6/6/2005 Residential (high density on-site 

wastewater disposal-septic systems 

and cesspools)

CH-6882 395807075432201 39°58’07” 75°43’23” 535 -- -- 64.03 6/7/2005 Residential (on-site wastewater disposal)

CH-6883 395715075404401 39°57’15” 75°40’45” 354 -- -- 17.89 6/8/2005 Residential (high density on-site 

wastewater disposal-septic systems 

and cesspools) and wooded

CH-SP-70 395807075450201 39°58’06” 75°45’03” 425 na -- 0 -- Agricultural (on-site wastewater 

disposal)2

CH-SP-71 395642075403801 39°56’42” 75°40’39” 290 na -- 0 -- Residential (high density on-site 

wastewater disposal-septic systems 

and cesspools)

1

Previously, the depth to water measured monthly in well CH-6673 during the period from December 2002 to January 2004 ranged from a maximum of 34.70 ft bls 

on July 14, 2003, to a minimum of 18.70 ft bls on June 10, 2003, suggesting that the value of 62.95 ft bls may be related to recent pumping of the well.

2

In sewer-service area.
Ground-Water and Base-Flow Water Quality 11

Analysis of Samples

Analyses of samples were selected to characterize general 

water quality and to screen for wastewater indicators. Wastewater indicators included chloride, nutrients (nitrogen and phosphorus compounds), boron (a laundry additive), selected 

organic compounds, and bacteria.

The pH, water temperature, alkalinity (acid neutralizing 

capacity), specific conductance, and concentration of dissolved 

oxygen were measured in the field for ground-water and baseflow samples using standard methods (U.S. Geological Survey, 

variously dated). Water samples were sent to the USGS 

National Water Quality Laboratory (NWQL) in Denver, Colo., 

to be analyzed for selected dissolved inorganic constituents and 

organic compounds. Analyses for inorganic constituents 

included major ions (calcium, magnesium, sodium, potassium, 

silica, sulfate, chloride, and fluoride), nutrients (nitrate, nitrite, 

ammonia, and orthophosphate), and selected trace elements 

(boron, iron, and manganese). Analyses for organic compounds 

included a suite of about 65 compounds commonly present in 

domestic or industrial wastewater (such as detergent metabolites, food additives, fragrances, antioxidants, flame retardants, 

plasticizers, industrial solvents, disinfectants, fecal sterols, 

polycyclic aromatic hydrocarbons, and high-use domestic pesticides) (Zaugg and others, 2002; Zaugg and Leiker, 2006). 

Many of these wastewater compounds are potential endocrinedisrupters or are toxic (Zaugg and others, 2002). Complete listings of constituents and compounds analyzed and associated 

parameter codes are given with analyzed data in tables 7 and 8 

at the back of the report.

Fecal coliform and enterococci bacteria were analyzed by 

the Chester County Health Department Laboratory in West 

Chester, Pa., using standard membrane filtration methods (such 

as described by Myers and Wilde, 1997). Membrane filtration 

and plating of samples were done within 6 hours of sample collection. The minimum detection level for fecal coliform and 

enterococci bacteria was 0.4 col/100 mL. 

For quality assurance, a replicate base-flow sample was 

collected from site 01480637 in September 2005 for analysis of 

inorganic constituents, organic wastewater compounds, and 

bacteria (table 7 at the back the report). No field or equipment 

blanks were collected because, in other studies done recently by 

USGS using the same or similar equipment and procedures, 

organic and inorganic analytes were not or were rarely detected 

in field and equipment blanks (Loper and others, 2007; Senior 

and Sloto, 2006; Reif, 2002) and funds for this study were limited. Also, samples for organic and bacteria analyses were collected directly from the stream or well head in bottles and had 

little to no contact with field equipment. In addition, laboratory 

blanks routinely are run during these analyses. Results of replicate inorganic analyses were within 2 percent of each other 

except for dissolved iron, which differed by 30 percent (but iron 

concentrations were low and differed by only 3 μg/L). Results 

of replicate analyses for bacteria differed by about 22 percent 

for enterococci and 13 percent for fecal coliform. Results of 

replicate analyses for organic wastewater compounds showed 

that five wastewater compounds were detected in at least one of 

the replicate samples. Of those five wastewater compounds, 

phenol concentrations were identical and two compounds (4-

nonylphenol and p-cresol) were detected in both replicates, and 

two compounds (camphor and methyl salicylate) were detected 

in only one of the replicates in September but had been detected 

previously in the May 2005 sample from this site. Phenol and 

acetophenone results should be used with caution because in 

some studies these compounds were detected in both field and 

laboratory blanks (Zaugg and Leiker, 2006). Recovery rates of 

surrogate compounds (caffeine-13C3, fluoranthene-d10, decafluorobiphenyl, and bisphenol-d3) added at the NWQL to the 

wastewater sample and used by the laboratory to measure gross 

sample-processing problems and matrix effects were generally 

within the range commonly reported by the NWQL (Zaugg and 

Leiker, 2006). These surrogate recovery rates indicate acceptable analytical results but are of limited use for assessing 

method compound recoveries (Zaugg and others, 2002). However, the generally poor recovery rate of bisphenol A-d3

(tables 7 and 8) indicates results for analyte bisphonol A are not 

reliable. Overall, the replicate analyses indicate no major quality-assurance problems, given the limited quality control, low 

concentrations, and possible false detections of organic wastewater compounds, and natural variability of bacteria. 

Ground-Water and Base-Flow Water 

Quality

Potential sources of constituents in ground water and base 

flow include precipitation, weathering of minerals in soils and 

rocks, and human activities on the land surface and subsurface. 

Biochemical and geochemical processes may alter the concentrations of many constituents, including trace metals (iron, manganese, and others), major cations (calcium, magnesium, 

sodium, and potassium), nutrients (nitrogen and phosphorus 

compounds), and organic compounds (natural and introduced). 

Processes that can increase or decrease the concentrations of 

constituents include sorption/desorption, ion exchange, oxidation/reduction, and biologically mediated reactions. Constituents that can be altered by such processes are considered to be 

non-conservative or semi-conservative tracers in the environment. Some inorganic constituents, such as chloride and boron, 

generally are not very reactive and commonly are considered 

conservative tracers in the environment.

Ground-water quality may vary locally because of local 

differences in soil types, aquifer lithology, and land use or other 

factors. The base-flow component of streamflow is groundwater discharge from the drainage area, and therefore, baseflow quality integrates (is a volume-weighted mixture of) the 

locally variable ground-water quality in a drainage area. Additional chemical and physical processes can change the composition of ground-water discharge (base flow) while and after it 

enters and is transported within the stream channel.
12 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

For the purposes of discussion of results of this pilot study 

in and near the Broad Run watershed, ground-water and baseflow sites sampled in 2005 were assigned to land-use categories 

listed in table 3. 

Inorganic Constituents

Water samples were analyzed for inorganic constituents to 

provide data about general water quality in each of the areas 

potentially affected by human activities. Inorganic analyses 

included major ions, nutrients, and the trace elements iron, manganese, and boron (tables 7and 8 at the back of the report). 

Nutrients, chloride, and boron are potential wastewater indicators, because they all typically are present in domestic sewage. 

Concentrations of chloride, boron, and nitrate are listed by sample type and land-use category in table 3. The range and average 

concentrations of selected inorganic constituents reported in 

septic-tank effluent are listed in table 4.

Table 3. Concentrations of chloride, boron, and nitrate in ground-water and base-flow samples collected May-June 2005 in and near the 

Broad Run watershed, Chester County, Pa., listed by land use for each tributary drainage area. Location of samples shown in fig. 3

[mg/L, milligrams per liter; μg/L, micrograms per liter; E, estimated value; <, less than]

U.S. 

Geological 

Survey local 

number or 

station 

number

Site 

type

Predominant land use -

type of wastewater disposal

Concentrations in water samples

Chloride 

(mg/L)

Dissolved Boron Nitrate 

oxygen (μg/L) (mg/L as N) (mg/L)

Manganese 

(μg/L)

Ground-water sites1

CH-6880 well residential - sewered 63.6 12 2.46 10.1 20.5

CH-SP-70 spring agricultural - on-site system2 26.1 8.3 9.18 8.3 .5E

CH-6882

CH-6879

well

well

residential - moderate-density on-site system2

residential - moderate-density on-site system2

32.3

242

23

4.9E

5.69

.97

9.0

8.5

5.1

8.4

CH-6673 well residential - moderate-density on-site system2 4.91 7.7 .40 2.7 25.0

CH-6878

CH-755

well

well

residential - high-density on-site system3

residential - high-density on-site system3

27.4

66.5

3.9E

27

6.26

10.7

5.8

9.1

2.9

39.2

CH-SP-71 spring residential - high-density on-site system3 30.4 11 2.68 8.9 <.6

CH-6881

CH-6883

well

well

residential - high-density on-site system3

residential - high-density on-site system3

wooded

373

5.37

26

8.2

3.11

7.32

5.3

9.7

279

.3E

Base-flow sites4

0148063522 stream residential - sewered 50.5 6.4E 3.23 11.0 4.8

0148063532 stream agricultural - on-site system2 21.4 8.5 6.37 10.0 16

014806368

014806366

stream

stream

residential - moderate-density on-site system2

residential - moderate-density on-site system2

29.1

39.3

33

28

6.29

4.45

10.5

11.0

3.7

5.4

014806369 stream residential - moderate-density on-site system2 37.1 29 4.14 10.3 51.9

01480637 stream residential - moderate-density on-site system2 34.6 29 4.01 10.6 19

014806374 seep undefined 20.0 7.5 3.33 5.8 17.5

014806384 stream residential - high-density on-site system3 65.0 44 6.61 10.5 2.1

014806394 stream residential - high-density on-site system3 30.6 14 2.82 10.7 4.6

01480913 stream wooded and residential - high-density on-site system3 11.7 11 1.94 10.4 37.1

1

Local number used for ground-water sites, where CH is the county code, SP denotes spring, and up 

spring in the county. 

to a 4-digit number is sequentially assigned for well or 

2

Typically septic system. 

3Septic system or cesspool. 

4Station number used for surface-water sites is assigned in downstream order.
Ground-Water and Base-Flow Water Quality 13

Chloride and boron are relatively stable (conservative indicators), but the nutrients may not be conservative. Denitrification and oxidation/reduction reactions can affect nitrogen compounds (nitrate, nitrite, and ammonia), and sorption can affect 

phosphorus compounds and ammonia. Most nitrogen enters the 

septic tanks as organic nitrogen and ammonia, but after the 

effluent leaves the tanks, it is oxidized in the soil zone to nitrate 

if sufficient oxygen is available. The oxidation of these nitrogen 

compounds and organic carbon produces acid and may lower 

pH in the vicinity of the plume from the tank (Robertson and 

Blowes, 1995). Wastewater disposal may change the geochemical environment through oxidation of organic compounds in 

wastewater that enter the ground-water system, resulting in 

depletion of oxygen in ground water. Nitrate is not stable in 

reducing environments, and subsequently, nitrate reduction 

decreases concentrations of nitrate. Concentrations of dissolved 

iron and manganese can be elevated in oxygen-depleted or 

reducing environments.

General Water Quality

In samples collected in the study area in 2005, ground 

water generally was acidic (pH ranged from 5.2 to 6.8), with 

low alkalinity [ranged from 9 to 47 mg/L as calcium carbonate 

(CaCO3)] and moderate hardness (based on calcium and magnesium concentrations, hardness ranged from 48 to 100 mg/L as 

CaCO3). The composition of ground water in the study area 

generally was within the range reported for water in schist aquifers in Chester County (Sloto, 1994), although the study-area 

ground water is slightly more acidic. Water samples from two 

wells (CH-6879 and CH-6881) had higher concentrations of 

calcium and magnesium than the other samples and, consequently, could be categorized as very hard (hardness of 286 and 

418 mg/L, respectively); these samples also had the highest 

concentrations of sodium and chloride and were in residential 

areas with on-site wastewater disposal. Ground water in all but 

three samples was well oxygenated (dissolved-oxygen saturation greater than 80 percent); concentrations of dissolved oxygen and percent saturation were lowest (ranging from 2.7 to 

5.8 mg/L and 26 to 55 percent, respectively) in samples from 

wells CH-6673, CH-6879, and CH-6881 (table 3 and table 8 at 

the back of the report), indicating oxygen depletion resulting 

from chemical or biochemical reactions. These three wells were 

in residential areas with on-site wastewater disposal. 

In comparison to the ground-water samples, base-flow 

samples collected in May-June 2005 had a more neutral to 

slightly alkaline pH (pH ranged from 7.0 to 8.0), with similarly 

low alkalinity (range for nine sites was 17 to 56 mg/L as 

CaCO3) and moderate hardness (range for eight sites was 53 to 

101 mg/L as CaCO3). Base flow from the seep site 014806374 

(fig. 5) had relatively high alkalinity (154 mg/L as CaCO3) and 

calcium and magnesium hardness (212 mg/L as CaCO3), suggesting that the water may be derived in part from the thin 

occurrence of carbonate bedrock in the study area (fig. 2). 

Table 4. Reported minimum, maximum, and average concentrations of selected constituents in 

septic-tank effluent. Modified from Senior, 1993.

[Sources: 1 = Canter and Knox (1985); 2 = Walker and others (1973); 3 = Andreoli and others (1979); 4 = Robertson and others (1991); 

5 = Roberston and Blowes (1995); 6 = Minnesota Pollution Control Agency (1999); 7 = Schreffler and others (2005); 8 = Vengosh and others 

(1994); mg/L milligrams per liter; μg/L, micrograms per liter; N, nitrogen; P, phosphorus; --, not reported]

Constituent or property Minimum Maximum Average Sources

Nitrate (mg/L as N) 0.1 1 0.1 3,4

Ammonia (mg/L as N) 40 100 70 2

Organic N (mg/L as N) 5 25 15 2

Phosphate (mg/L as P) -- -- 15 1

Chloride (mg/L) 37 200 53 1,2,4

Iron (mg/L) 0 20 2.6 1

pH (pH units) 6.5 7.5 6.9 1,3

Alkalinity -- -- 186 3

Calcium (mg/L)1 2855

Magnesium (mg/L)1 021.5 5

Sodium (mg/L)1 25 50 38 4, 5

Potassium (mg/L)1 12 40 26 4, 5

Sulfate (mg/L)1 0 36 -- 4

Boron (μg/L) 55 13,248 2

400 6, 7, 8

1

Constituent concentration adjusted for background concentrations in source water (upgradient ground water).

2Median of three studies (for 8 septic systems in Minnesota, median was 616 μg/L; for spray effluent in Chester County 

site, median was less than 200 μg/L; for raw sewage, adjusted for background, in Israel, median was about 400 μg/L).
14 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Concentrations of dissolved iron and manganese in ground 

water generally were low. In ground-water samples collected in 

June 2005, concentrations of dissolved iron were near or below 

the reporting level of 6 μg/L in water from all but one well. The 

concentration of dissolved iron was 619 μg/L in water from well 

CH-6881, exceeding the U.S. Environmental Protection 

Agency (USEPA) secondary maximum contaminant level 

(SMCL) of 300 μg/L for iron in drinking water. Similarly, concentrations of dissolved manganese were less than 40 μg/L in 

water from all but the same well (CH-6881), which had a concentration of dissolved manganese of 279 μg/L, exceeding the 

USEPA SMCL of 50 μg/L for manganese. Water from this well 

had oxygen concentrations below saturation (table 8 at the back 

of the report).

Concentrations of dissolved iron and manganese in baseflow samples collected May-June 2005 also were relatively 

low, ranging from less than 6 to 43 μg/L for dissolved iron and 

2.1 to 51.9 μg/L for dissolved manganese. The highest baseflow concentrations of dissolved iron and manganese were in 

samples from stream site 014806369 that drains a residential 

area with septic systems (fig. 3).

Nitrate and Other Nutrients

Natural background concentrations of nitrate in ground 

water and base flow are about 1 mg/L as nitrogen (N) or less in 

the study area, as estimated from precipitation chemistry 

(Senior and others, 1997). Nitrate concentrations were greater 

than background concentrations of 1 mg/L as N in most groundwater samples and all base-flow samples collected in the study 

area (table 3; fig. 7), indicating probable addition of nitrate 

from human activities, such as application of fertilizers and use 

of septic systems. Nitrate was elevated above natural background in samples from all land-use areas—agricultural, residential with sewers, and residential with on-site wastewater disposal.

Nitrate concentrations were more variable in ground-water 

samples than in base-flow samples and ranged from 0.4 mg/L 

up to 10.7 mg/L as N. Nitrate concentrations were highest 

(greater than 6 mg/L as N) in ground-water samples from the 

agricultural area (spring CH-SP-70) and the residential area 

with high-density on-site wastewater disposal systems (wells 

CH-755, CH-6883, and CH-6878) (fig. 7). The highest nitrate 

concentration (10.7 mg/L as N) was in water from residential 

well CH-755, which exceeded the drinking-water maximum 

contaminant level (MCL) of 10 mg/L as N for nitrate established by the USEPA to protect human health. The low concentrations of nitrate in some ground-water samples in areas with 

septic systems may be partly attributable to loss through oxidation-reduction reactions. Some of the lower concentrations of 

nitrate observed are associated with lower concentrations of 

dissolved oxygen (table 3).

The highest concentrations of nitrate in the May 2005 

base-flow samples (about 6 mg/L as N) also were in streams 

draining the agricultural area (site 0148063522) and the residential area with high-density on-site wastewater disposal (site 

014806384), in addition to a stream draining a residential area 

with septic systems (site 014806368) (fig. 7). The lowest concentrations of nitrate in the May 2005 base-flow samples (about 

2 to 3 mg/L as N) were in streams draining the residential area 

with sewers (site 0148063522), one of the residential areas with 

high-density on-site wastewater disposal (site 014806394), and 

a mixed forested/residential area (site 01480913) (fig. 7). About 

half the drainage area above stream site 01480913 that had the 

lowest nitrate concentration in base flow apparently is forested 

(fig. 3). Base-flow concentrations of nitrate in the residential 

area with moderate-density on-site wastewater disposal generally were about 4 mg/L as N in May 2005.

Concentrations of nitrite and ammonia, nitrogen compounds that are stable under reducing conditions, were low in 

ground-water and base-flow samples collected May-June 2005 

(table 8 at the back of the report). Nitrite and ammonia commonly are present in septic-system effluent and fertilizers. 

Nitrite concentrations were below the reporting level of 

0.008 mg/L as N in all but the base-flow samples from site 

014806369 and nearby downstream site 01480637, which drain 

a residential area with moderate-density on-site wastewater disposal (fig. 3), in which nitrite concentrations were 0.027 and 

0.019 mg/L as N, respectively. Ammonia concentrations were 

below the reporting level of 0.04 mg/L as N in base-flow samples from all but site 014806389, which had 0.06 mg/L as N of 

ammonia and also had the highest detected nitrite concentration. 

Concentrations of dissolved orthophosphate, a soluble 

form of phosphorus, in ground-water and base-flow samples 

collected in May-June 2005 were low (tables 7 and 8 at the back 

of the report). Orthophosphate concentrations were less than the 

reporting level of 0.02 mg/L as P in all spring 2005 base-flow 

samples. Orthophosphate concentrations in ground-water samples were slightly higher than in base-flow samples and ranged 

from 0.01 to 0.04 mg/L as P. The highest orthophosphate concentrations in ground water (0.3 to 0.4 mg/L as P) were in the 

four wells CH-755, CH-6878, CH-6883, and CH-6882 in residential areas; three of these four wells were in the residential 

areas with high-density on-site wastewater disposal, and the 

remaining well was in the residential area with moderate-density on-site wastewater disposal (table 8 at the back of the 

report; fig. 3).

Chloride

Natural background concentrations of chloride in ground 

water and base flow are about 10 mg/L or less, as estimated 

from precipitation chemistry (Senior and others, 1997). Chloride concentrations were greater than 10 mg/L in most groundwater samples and all base-flow samples collected in the study 

area (table 3; fig. 8), indicating probable additions of chloride 

from human activities, such as road salting and septic systems. 

Chloride was elevated above natural background levels in sam-
Ground-Water and Base-Flow Water Quality 15

ples from all land-use areas—agricultural, residential with sewers, and residential with on-site wastewater disposal. 

Chloride concentrations were more variable in groundwater samples than in base-flow samples and were highest in 

ground-water samples from residential areas (table 3). The 

highest measured chloride concentrations of 373 and 242 mg/L 

in samples from wells CH-6881 and CH-6879, respectively, 

both in areas with on-site wastewater disposal (septic or septic 

and cesspool), were near or greater than the USEPA SMCL for 

chloride of 250 mg/L in drinking water. The highest concentrations of chloride in base-flow samples (50 to 65 mg/L) were in 

streams draining the residential area with sewers (site 

0148063522) and a residential area with high-density on-site 

wastewater disposal (site 014806384); the lowest chloride concentrations (11.7 to 21.4 mg/L) were in streams draining agricultural (site 0148063532) or mixed forested/residential areas 

(site 01480913) (table 3, fig. 8). Base-flow concentrations of 

chloride in the residential area with moderate-density on-site 

wastewater disposal ranged from 29 to 39 mg/L.

The predominant source of chloride is salt, either as 

sodium or calcium chloride in road salt or in septic effluent. 

Chloride concentrations are correlated most strongly with 

sodium concentrations in samples collected in May-June 2005 

and to a lesser extent with magnesium, calcium, and potassium 

0 2 4 6 8 10 12

NITRATE, IN MILLIGRAMS PER LITER AS NITROGEN

ESTIMATED NATURAL 

BACKGROUND LEVEL

DRINKING-WATER MAXIMUM 

CONTAMINANT LEVEL

EXPLANATION - Concentrations shown by land use and site type, in approximate downgradient order from ground-water site to 

base-flow site in each land-use category. 

RESIDENTIAL

(SEWERED)

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

CH-6880

0148063522

CH-SP-70

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

0148063532

014806368

014806366

014806369

01480637

014806374

014806384

014806394

01480913

GROUND WATER

BASE FLOW

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

UNDEFINED

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SITE TYPE

SITE

IDENTIFICATION

NUMBER 

Figure 7. Nitrate concentrations in ground-water and base-flow samples in areas of different land uses in and near the Broad Run 

watershed, Chester County, Pa., May-June 2005. See figure 3 for location of sites.
16 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

concentrations. Sodium enrichment is likely to occur with chloride enrichment in ground water and base flow, regardless of the 

source of chloride. Sodium concentrations above 20 mg/L may 

pose a health concern and above 60 mg/L may pose a taste problem (U.S. Environmental Protection Agency, 2006). The relation between sodium and chloride concentrations for the MayJune 2005 base-flow and ground-water samples (fig. 9) shows 

that base-flow and ground-water concentrations of sodium and 

chloride are similar for each of the land uses. Points plotting 

near the line showing the 1:1 molar ratio of sodium to chloride 

indicate that most of the chloride is associated with sodium; 

points plotting above the line indicate excess sodium relative to 

chloride, and points plotting below the line indicate excess chloride relative to sodium. 

Boron

Natural background concentrations of boron in ground 

water and base flow will vary by lithology and probably are 

about 20 μg/L or less in the study area based on previous investigations (Sloto, 1994; Senior and others, 1997). Boron concentrations were greater than 20 μg/L in 3 of 10 ground-water samples and in 5 of 10 base-flow samples collected May-June 2005 

0 20 40 60 80 100

CHLORIDE, IN MILLIGRAMS PER LITER

ESTIMATED NATURAL 

BACKGROUND LEVEL

OFF SCALE

AT 242 MG/L

OFF SCALE

AT 373 MG/L

RESIDENTIAL

(SEWERED)

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

CH-6880

0148063522

CH-SP-70

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

0148063532

014806368

014806366

014806369

01480637

014806374

014806384

014806394

01480913

GROUND WATER

BASE FLOW

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

UNDEFINED

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SITE TYPE

EXPLANATION - Concentrations shown by land use and site type, in approximate downgradient order from ground-water site to 

base-flow site in each land-use category. 

SITE

IDENTIFICATION

NUMBER 

Figure 8. Chloride concentrations in ground-water and base-flow samples in areas of different land uses in and near the Broad 

Run watershed, Chester County, Pa., May-June 2005. See figure 3 for location of sites.
Ground-Water and Base-Flow Water Quality 17

(table 3), suggesting some possible addition of boron from 

human activities, such as laundry discharge into septic systems. 

Boron was elevated above 20 μg/L (estimated maximum natural 

background concentration in study area) only in samples from 

the residential areas with on-site wastewater disposal (fig. 10). 

Boron concentrations ranged up to 27 μg/L in the June 

2005 ground-water samples and up to 44 μg/L in the May 2005 

base-flow samples. No sample contained boron in concentrations above the current USEPA life-time health advisory of 

1 mg/L (1,000 μg/L) for drinking water (U.S. Environmental 

Protection Agency, 2006). The highest concentrations of boron 

in ground water (26 to 27 μg/L) were in samples from wells in 

the residential area with high-density on-site wastewater disposal (CH-6881 and CH-755) (table 3, fig. 10). The highest 

concentrations of boron in base flow (28 to 44 μg/L) were in 

streams draining the residential areas with moderate-density 

and high-density on-site wastewater disposal (sites 014806366, 

014806369, 01480637, 014806368, and 014806384), and the 

lowest concentrations (6 to 11 μg/L) were in streams draining 

the agricultural area (site 0148063532), the residential area with 

sewers (site 0148063522), and the mixed forested/residential 

area (site 01480913) (table 3, fig. 10). 

Organic Compounds

Of the 62 compounds in the emerging contaminant analysis, 30 different organic wastewater compounds were detected 

(table 5). The types of compounds detected included disinfectants, flavors, fragrances, detergent metabolites, flame retardants, fumigants, components of coal tar and feces, pesticides, 

solvents, and wood preservatives. Generally low levels of the 

wastewater compounds were measured. The concentrations of 

most compounds were at or below reporting levels (tables 7 

and 8 at the back of the report) that ranged from less than 

0.5 μg/L to less than 5 μg/L. The reporting levels were less than 

0.5 μg/L for 42 compounds, less than 1 μg/L for 11 compounds, 

less than 2 μg/L for 6 compounds, and less than 5 μg/L for 

3 compounds. Most compounds detected in samples are 

reported as “measured” concentrations (listed as “M” in tables 7 

and 8), which means the compound was detected below the laboratory method reporting level (MRL) but the concentration 

could not be quantified precisely. Some compounds are 

reported as “estimated” concentrations (listed as “E” in tables 7 

and 8), which means the laboratory was relatively confident in 

quantifying a concentration that was less than the MRL for that 

analyte. Phenol was the only compound for which concentrations consistently were reported in quantity above the MRL.

More compounds were detected in base-flow samples 

(25 compounds) collected May-June and September 2005 than 

in ground-water samples (17 compounds) collected June 2005, 

DISSOLVED SODIUM, IN MILLIGRAMS PER LITER

DISSOLVED CHLORIDE, IN MILLIGRAMS PER LITER

1

10

100

Ground water - residential, sewered

Ground water - residential, on-site wastewater disposal

(septic systems and cesspools)

Ground water - agricultural

Base flow- residential, sewered

Base flow- residential, on-site wastewater disposal

(septic systems and cesspools)

Base flow- residential, agricultural

EXPLANATION

1 :1 MO LAR

R ATIO

Mixed residential/wooded

sites

Estimated natural

background for chloride

1 10 100 1,000

Figure 9. Sodium and chloride concentrations in ground-water and base-flow samples in areas of different land uses in and 

near the Broad Run watershed, Chester County, Pa., May-June 2005.
18 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

BORON, DISSOLVED, IN MICROGRAMS PER LITER

0 10 20 30 40 50

ESTIMATED NATURAL 

BACKGROUND LEVEL

RESIDENTIAL

(SEWERED)

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

CH-6880

0148063522

CH-SP-70

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

0148063532

014806368

014806366

014806369

01480637

014806374

014806384

014806394

01480913

GROUND WATER

BASE FLOW

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

UNDEFINED

LAND USE

(TYPE OF WASTEWATER 

DISPOSAL) SITE TYPE

EXPLANATION - Concentrations shown by land use and site type, in approximate downgradient order from ground-water site to 

base-flow site in each land-use category. 

SITE

IDENTIFICATION

NUMBER 

Figure 10. Boron concentrations in ground-water and base-flow samples in areas of different land uses in and near the Broad Run 

watershed, Chester County, Pa., May-June 2005. See figure 3 for location of sites.
Ground-Water and Base-Flow Water Quality 19

Table 5. Organic wastewater compounds detected in samples from 10 surface-water and 10 ground-water sites, May-June and September 2005, Broad Run watershed and vicinity, Chester County, Pa., listed in order of the number of surface-water sites with detections.

[μg/L, micrograms per liter; sp, spring; Other studies: H = Hinkle and others (2005); K = noted by Hinkle and others (2005) to be also frequently detected in 

wastewater-affected surface water by Kolpin and others (2002); C = detected in ground water in Chester County (see table 6)]

Organic wastewater compound (use or origin) Parameter 

code

Method 

reporting 

level

(μg/L)

Number of surface-water 

sites with detections1

Number of groundwater sites with 

2 detections

Compound 

frequently 

detected in 

other studies 

of on-site 

wastewater

May-June September 

2005 20053

10 sites 8 sites 

sampled sampled

June

2005 

10 sites 

sampled

Phenol (disinfectant, leachate)

Methyl salicylate (food, liniment)

Camphor (flavor, ointments)

para-Nonylphenol (detergent metabolite)

Isophorone (solvent)

para-Cresol (wood preservative)

Tri(dichloroisopropyl)phosphate (flame retardant)

Skatol4

 (constituent in feces, coal tar)

DEET5 (insect repellent)

Metolachlor (agricultural pesticide)

4-n-Octylphenol (detergent metabolite)

AHTN6

 (musk fragrance)

Fluoranthene (coal tar, asphalt)

Indole (fragrance in coffee)

Octylphenol,monoethoxy- (detergent metabolite)

Phenanthrene

Pyrene (coal tar, asphalt)

Anthracene (wood preservative)

Menthol (flavor, fragrance)

1,4-dichlorobenzene (fumigant)

Caffeine (beverages)

Napthalene (fumigant)

Tri (2-chloroethyl)phosphate7 (flame retardant)

Chlorpyrifos (pesticide - termites)

Octylphenol, diethoxy (detergent metabolite)

Tetrachloroethylene (solvent)

Tri(2-butoxyethyl)phosphate (flame retardant)

Acetophenone (fragrance in detergent, tobacco.)

Benzophenone (perfumes, soaps)

4-tert-Octylphenol (detergent metabolite)

34466

62081

62070

62085

34409

62084

62088

62058

62082

39415

62061

62065

34377

62706

61706

34462

34470

34221

62080

34572

50305

34443

62087

38933

61705

34476

62093

62064

62067

62062

0.5

.5

.5

5

.5

1

.5

1

.5

.5

1

.5

.5

.5

1

.5

.5

.5

.5

.5

.5

.5

.5

.5

1

.5

.5

.5

.5

1

9

2

3

0

5

3

4

3

2

3

3

3

0

2

2

2

0

2

2

2

2

0

1

1

1

0

0

0

0

0

7 (6)

8 (2)

6 (2)

5 (0)

0 

3 (2)

0

1 (0)

2 (1)

1 (1)

0

0

3 (0)

1(0)

0

2(1)

3(0)

0

0

0

1(1)

2 (0)

0

0

0

0

0

0

0

0

9 (2 sp)

2 (2 sp)

1 (1 sp)

0

2 (2 sp)

2 (2 sp)

1

0

3 (2 sp)

1 (1sp)

0

0

0

0

0

0

0

2

2 (2 sp)

1 

0

0

1

0

0

2 (1 sp)

2 (1 sp)

2 (1 sp)

2 (2 sp) 

1

C

H, K

C

H

H, K, C

C

H

C

H

C

H

H, K, C

H, K, C

C

C

C

1All compounds except phenol were detected at concentrations below the method reporting level. 

2Total number of ground-water sites with detections (with number of springs shown in parentheses).

3

Number of surface-water sites that had detections in both fall and spring shown in parentheses.

4

3-methyl-1H-indole.

5N,N-diethyl-meta-toluamide.

6

acetyl-hexamethyl-tetrahydro-napthalene.

7

FYROL CEF.
20 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

suggesting potential preferential pathways for on-site wastewater disposal to streams through shallow ground-water flow. 

Comparing results of base-flow and ground-water sampling 

during the spring period only (May-June 2005), 12 of the 

21 compounds detected at base-flow sites also were detected in 

1 or more ground-water sites. For ground water, more compounds were detected in samples from the 2 springs (12 compounds) than in samples from the 8 wells (9 compounds) 

(table 5, table 8 at the back of the report). 

In samples from springs, a larger number of organic wastewater compounds were detected in the sample collected in the 

agricultural area (12 compounds, spring CH-SP-70) than in the 

sample collected in the residential area with high-density onsite wastewater disposal (8 compounds, spring CH-SP-71) 

(fig. 11). Many of the specific compounds detected in the 

ground-water samples from the two springs were the same and 

included phenol, methyl salicylate, isophorone, para-Cresol, 

DEET, menthol, and benzophenone (table 5 and table 8 at the 

back of the report). Of the well-water samples, more compounds generally were detected in samples from wells in the 

residential areas with high-density on-site wastewater disposal 

(up to three compounds in samples from wells CH-755 and

CH-6878) than elsewhere, although the largest number of 

wastewater compounds detected in a well-water sample (four 

compounds) was from well CH-6879 in the residential area with 

moderate-density on-site wastewater disposal (fig. 11). Compounds detected in well-water samples included phenol, DEET, 

a few flame retardants, a solvent, a fragrance, a detergent 

metabolite, and a fumigant (table 5 and table 8 at the back of the 

report).

Of the base-flow samples collected in May-June 2005, the 

largest number of organic wastewater compounds (10 to 14 

compounds) were detected in samples from sites in the residential area with moderate-density on-site wastewater disposal 

(sites 014806369, 01480637, 014806368) and the fewest 

(1 compound) was in a sample from the sewered residential area 

(site 0148063522) (fig. 11). The base-flow sample from the site 

in the agricultural area (0148063532) had more compounds (7 

compounds) than base-flow samples from the residential area 

with high-density on-site wastewater disposal (2 to 4 compounds) (fig. 11).

Bacteria

Bacteria were detected in all base-flow samples but in only 

3 of the 10 ground-water samples, 2 of which were springs, in 

the June 2005 sampling period. Bacteria concentrations could 

not be determined in one ground-water sample from well 

CH-6881 because suspended sediment impaired bacteria 

growth on the plate. Bacteria concentrations in the groundwater samples from springs ranged from 2 to 18 col/100 mL for 

enterococci and 0.8 to 6 col/100 mL for fecal coliform. Enterococci bacteria were detected in only one well-water sample at a 

concentration of 0.4 col/100 mL (just at the detection level); this 

well (CH-6673) is in a residential area with septic systems 

(fig. 3). The highest concentration of bacteria in ground-water 

samples was from spring CH-SP-70 in the agricultural area. To 

protect human health in drinking water, the USEPA recommends a MCL goal (MCLG) of zero total coliforms [including 

fecal coliforms and Escherichia coli (E. coli)] (U.S. Environmental Protection Agency, 2006). The sample from spring 

CH-SP-70 (fig. 12) had 6 col/100 mL of fecal coliform bacteria, 

exceeding the MCLG for drinking water. 

Enterococci bacteria were detected in base-flow samples 

from all 10 sites and fecal coliform were detected in base-flow 

samples from all but 1 of the 10 stream sites in May 2005. 

Enterococci ranged in concentration from 20 to 960 col/100 mL 

and fecal coliform concentrations ranged from less than 1 to 

310 col/100 mL in base-flow samples. Enterococci concentrations were greater than fecal coliform concentrations in 9 of the 

10 base-flow samples (table 7). The highest concentrations of 

bacteria in May 2005 base-flow samples (greater than 

100 col/100 mL for both enterococci and fecal coliform) were 

from the residential area with sewers (site 0148063522), the 

agricultural area (site 0148063532), the residential area with 

moderate-density on-site wastewater disposal (site 014806369), 

and the residential area with high-density on-site wastewater 

disposal (site 014806384) (fig. 12). 

Bacteria were present in relatively elevated concentrations 

in base flow from all land-use areas. Sources of the bacteria are 

unknown but could include wildlife or domesticated animals. In 

an evaluation of bacteria in Chester County, Pa., in 1998-99, the 

median concentration of fecal coliform in base flow did not 

appear to differ by land use and were about 250 col/100 mL for 

areas draining agricultural, forested, residential, and mixed land 

uses (Town, 2001, p. 12).

To protect human health in recreational waters, the 

USEPA recommends using E. coli bacteria in fresh waters and 

enterococci bacteria in fresh or marine waters and suggests the 

standards of 126 col/100 mL for E. coli and 33 col/100 mL for 

enterococci bacteria in fresh waters (U.S. Environmental Protection Agency, 1986). The Commonwealth of Pennsylvania 

uses a standard of 200 col/100 mL for fecal coliform bacteria in 

recreational waters during the swimming season, May 1 

through September 30 (Pennsylvania Department of Environmental Protection, 1996). On the basis of the one-time sampling 

(rather than the 5-day geometric mean specified in the standards), bacteria in samples from eight stream sites exceeded the 

USEPA standard of 33 col/100 mL for enterococci and from 

one of the eight stream sites exceeded the state standard of 

200 col/100 mL for fecal coliform (fig. 12, table 7 at the back of 

the report). 
Ground-Water and Base-Flow Water Quality 21

NUMBER OF WASTEWATER COMPOUNDS DETECTED

0 5 10 15

RESIDENTIAL

(SEWERED)

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

CH-6880

0148063522

CH-SP-70

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

0148063532

014806368

014806366

014806369

01480637

014806374

014806384

014806394

01480913

GROUND WATER

BASE FLOW

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

UNDEFINED

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SITE TYPE

EXPLANATION - Concentrations shown by land use and site type, in approximate downgradient order from ground-water site to 

base-flow site in each land-use category. 

SITE

IDENTIFICATION

NUMBER 

Figure 11. Number of wastewater compounds detected in ground-water and base-flow samples in areas of different land uses in 

and near the Broad Run watershed, Chester County, Pa., May-June 2005. See figure 3 for location of sites.
22 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

EXPLANATION - Concentrations shown by land use and site type, in approximate downgradient order from ground-water site to 

base-flow site in each land-use category. [Abbreviation: U.S. EPA, U.S. Environmental Protection Agency]

ENTEROCOCCI CONCENTRATION, IN COLONIES PER 100 MILLILITERS

0.1 1 10 100 1,000

U.S. EPA 

MAXIMUM LEVEL OF 

33 COL/100 ML 

FOR RECREATIONAL 

WATER

RESIDENTIAL

(SEWERED)

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

CH-6880

0148063522

CH-SP-70

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

0148063532

014806368

014806366

014806369

01480637

014806374

014806384

014806394

01480913

GROUND WATER

BASE FLOW

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

UNDEFINED

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SITE TYPE

NO DATA

REPORTED DETECTION

OF 0.4 COL/100 ML 

MINIMUM REPORTING

LEVEL OF 0.4 COL/100 ML 

SITE

IDENTIFICATION

NUMBER 

A.

Figure 12. Bacteria concentrations in ground-water and base-flow samples in areas of different land uses in and near the Broad 

Run watershed, Chester County, Pa., May-June 2005. 

See fig. 3 for location of sites.
Ground-Water and Base-Flow Water Quality 23

RESIDENTIAL

(SEWERED)

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

CH-6880

0148063522

CH-SP-70

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

0148063532

014806368

014806366

014806369

01480637

014806374

014806384

014806394

01480913

GROUND WATER

BASE FLOW

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

GROUND WATER

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

BASE FLOW

UNDEFINED

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SITE TYPE

EXPLANATION - Concentrations shown by land use and site type, in approximate downgradient order from ground-water site to 

base-flow site in each land-use category. [Abbreviation: PADEP, Pennsylvania Department of Environmental Protection]

FECAL COLIFORM CONCENTRATION, IN COLONIES PER 100 MILLILITERS

PADEP MAXIMUM LEVEL OF 

200 COL/100 ML FOR 

RECREATIONAL WATER

REPORTED AS 

LESS THAN 1 COL/100 ML 

0.1 1 10 100 1,000

NO DATA MINIMUM REPORTING

LEVEL OF 0.4 COL/100 ML 

SITE

IDENTIFICATION

NUMBER 

B.

Figure 12. Bacteria concentrations in ground-water and base-flow samples in areas of different land uses in and near the Broad 

Run watershed, Chester County, Pa., May-June 2005.—Continued 

See figure 3 for location of sites.
24 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Seasonal Base-Flow Quality

Of the 10 stream sites sampled in May-June 2005, only 8 

were re-sampled in September 2005 because 2 sites 

(0148063522 and 014806374) were dry in September. Base 

flow at the eight sites with flow in September 2005 was about 

25 percent of the flow (range 7 to 34 percent) in May 2005 

(fig. 13). The hydrograph for streamflow-measurement station 

014806368 Broad Run at Northbrook, Pa., near the bottom of 

the watershed (fig. 3), shows the decline in streamflow (fig. 4). 

Ground-water levels also declined from May to September 

2005 as measured in a nearby long-term observation well, 

CH-12 (fig. 3), in which the water level declined about 5 ft 

(4.86 ft) from 32.40 to 37.26 ft bls during that period (Durlin 

and others, 2006, p. 493).

Despite the decrease in streamflow, concentrations of most 

major ions in base flow remained relatively constant from May 

to September 2005 (table 7 at the back of the report). Generally, 

the concentrations of most major ions in September base-flow 

samples were similar or slightly (commonly about 5 to 20 percent) higher than concentrations in the May base-flow samples. 

Nitrate concentrations in base-flow samples were about 10 percent lower in September than in May 2005. The lower nitrate 

concentrations in September may be related to nutrient uptake 

by algae in the stream. The relatively constant composition of 

0 0.2 0.4 0.6 0.8 1.0

STREAMFLOW, IN CUBIC FEET PER SECOND

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SAMPLE DATE

0148063532

0148063532

014806368

014806368

014806366

014806366

014806369

014806369

01480637

01480637

014806384

014806384

014806394

014806394

01480913

01480913

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

SITE

IDENTIFICATION

NUMBER 

Figure 13. Base flow in areas of different land uses in and near the Broad Run watershed, Chester County, Pa., in May and 

September 2005. 

See figure 3 for location of sites.
Ground-Water and Base-Flow Water Quality 25

base flow during this period indicates that the overall composition of ground water discharging to the stream also did not vary 

much. 

The concentrations of boron and bacteria, however, did 

change generally by more than 20 percent in base-flow samples 

from May to September 2005. The concentrations of boron in 

base-flow samples were two to three times higher in September 

than in May 2005. The reason for the apparent increase in boron 

concentrations from May to September and the lack of comparable increases of other constituents of probable anthropogenic 

origin, such as chloride, is unknown. Concentrations of boron in 

September 2005 base-flow samples ranged from 26 to 90 μg/L; 

the highest concentrations (greater than 45 μg/L) were in base 

flow draining the residential area with moderate-density on-site 

wastewater disposal (sites 01480368, 014806366, 014806369, 

and 01480637) and a residential area with high-density on-site 

wastewater disposal (site 014806384) (fig. 14). The sites with 

the highest concentrations of boron in base flow in September 

2005 also had the highest concentrations of boron in base flow 

in May 2005. 

BORON CONCENTRATIONS, IN MICROGRAMS PER LITER

0 20 40 60 80 100

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SAMPLE DATE

0148063532

0148063532

014806368

014806368

014806366

014806366

014806369

014806369

01480637

01480637

014806384

014806384

014806394

014806394

01480913

01480913

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

ESTIMATED NATURAL 

BACKGROUND LEVEL 

SITE

IDENTIFICATION

NUMBER 

Figure 14. Boron concentrations in base flow in areas of different land uses in and near the Broad Run watershed, Chester County, 

Pa., in May and September 2005. 

See figure 3 for location of sites.
26 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Enterococci concentrations in base-flow samples were 

greater by one to two orders of magnitude (factors of 10 to 100) 

in September 2005 compared to May 2005 (fig. 15a). In contrast to enterococci, concentrations of fecal coliform in baseflow samples were about the same order of magnitude in September and May 2005 except at two sites (01480913 and 

014806394) where the September concentrations were two 

orders of magnitude greater than the May concentrations 

(fig. 15b). Bacteria concentrations in streams commonly are 

greatest during the warmest months of the year, from June to 

September in Chester County, Pa. (Town, 2001, p. 14-15). In 

the study area, base-flow temperatures were 2 to 5 degrees Celsius higher in September than in May 2005 (table 7 at the back 

of the report). 

ENTEROCOCCI CONCENTRATIONS, IN COLONIES PER 100 MILLILITERS

A.

1 10 100 1,000 10,000

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SAMPLE DATE

0148063532

0148063532

014806368

014806368

014806366

014806366

014806369

014806369

01480637

01480637

014806384

014806384

014806394

014806394

01480913

01480913

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

U.S. EPA MAXIMUM LEVEL 

OF 33 COL/100 ML 

FOR RECREATIONAL WATER

EXPLANATION - [Abbreviations: U.S. EPA, U.S. Environmental Protection Agency]

SITE

IDENTIFICATION

NUMBER 

Figure 15. Concentrations of (A) enterococci and (B) fecal coliform bacteria in base flow in areas of different land uses in and near 

the Broad Run watershed, Chester County, Pa., in May and September 2005. 

See figure 3 for location of sites.
Ground-Water and Base-Flow Water Quality 27

FECAL COLIFORM CONCENTRATIONS, IN COLONIES PER 100 MILLILITERS

1 10 100 1,000 10,000

B.

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

LAND USE

(TYPE OF WASTEWATER

DISPOSAL) SAMPLE DATE

0148063532

0148063532

014806368

014806368

014806366

014806366

014806369

014806369

01480637

01480637

014806384

014806384

014806394

014806394

01480913

01480913

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

PADEP MAXIMUM LEVEL 

OF 200 COL/100 ML 

FOR RECREATIONAL WATER

LESS THAN 1 COL/100ML

EXPLANATION - [Abbreviation: PADEP, Pennsylvania Department of Environmental Protection]

SITE

IDENTIFICATION

NUMBER 

Figure 15. Concentrations of (A) enterococci and (B) fecal coliform bacteria in base flow in areas of different land uses in and near 

the Broad Run watershed, Chester County, Pa., in May and September 2005.—Continued

See figure 3 for location of sites.
28 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

The number and concentrations of the analyzed emerging 

contaminant organic wastewater compounds differed in MayJune and September 2005 samples. More compounds were 

detected in May-June 2005 base flow than in September 2005 

base flow (fig. 16). Twenty-one organic wastewater compounds 

were detected in May-June 2005 base-flow samples and 14 

compounds were detected in September 2005 base-flow samples (table 5). Eight compounds, including phenol, methyl salicylate, camphor, para-Cresol, DEET, metolachlor, phenanthrene, and caffeine, were detected in both the May-June and 

the September 2005 base-flow samples (table 5). Given the low 

reported concentrations of most of the organic wastewater compounds, some of the differences between the May-June and 

September detections could be caused by variations in recovery 

and analysis at the laboratory. Phenol is the only compound 

with sufficient quantified concentrations to compare May-June 

and September 2005 results. Phenol concentrations in baseflow samples were greater in September 2005 than in May-June 

2005 at six of the eight sites sampled in both periods (table 7 at 

the back of report).

NUMBER OF WASTEWATER COMPOUNDS DETECTED

0 2 4 6 8 10 12 14 16

AGRICULTURAL

RESIDENTIAL

(MODERATE DENSITY

ON-SITE)

RESIDENTIAL

(HIGH DENSITY 

ON-SITE)

LAND USE

(TYPE 0F WASTEWATER

DISPOSAL) SAMPLE DATE

0148063532

0148063532

014806368

014806368

014806366

014806366

014806369

014806369

01480637

01480637

014806384

014806384

014806394

014806394

01480913

01480913

MAY 2005

SEPTEMBER 2005

JUNE 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

JUNE 2005

SEPTEMBER 2005

JUNE 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

MAY 2005

SEPTEMBER 2005

SITE

IDENTIFICATION

NUMBER 

Figure 16. Number of organic wastewater compounds detected in base flow in areas of different land uses in and near the Broad 

Run watershed, Chester County, Pa., in May and September 2005. 

See figure 3 for location of sites.
Ground-Water and Base-Flow Water Quality 29

Effects of On-Site Wastewater Disposal 

On the basis of the limited data, results of the pilot study in 

the Broad Run watershed indicate that the combination of 

nitrate, chloride, and boron were inorganic indicators of effects 

of on-site wastewater disposal on ground-water and associated 

base-flow water quality. Nitrate concentrations were higher in 

residential areas with on-site disposal than in residential areas 

with sewers. Nitrate concentrations were as high as 10.7 mg/L 

as N in ground water and 6.6 mg/L as N in base flow from the 

residential areas with on-site disposal. Chloride concentrations 

in ground-water and base-flow samples generally were higher 

in residential areas (with sewers and on-site wastewater disposal) than in the agricultural areas. Boron concentrations in 

most base-flow samples and in some ground-water samples 

were higher in residential areas with on-site disposal than in residential areas with sewers or in agricultural areas. 

The presence of some organic wastewater compounds in 

both ground water and base flow in the study area indicates that 

the effects of on-site wastewater disposal are not limited to an 

increase in concentrations of nitrate, boron, and chloride. 

Apparently, some of the organic wastewater compounds can 

enter the ground-water system and later be discharged to 

streams. The results showing that the largest number of organic 

wastewater compounds were detected in streams and that the 

springs had the larger number of wastewater compounds 

detected compared to the well-water samples suggest transport 

of these compounds along shallow flow paths. More organic 

wastewater compounds were detected in ground-water samples 

from the residential area with high-density on-site wastewater 

disposal (septic systems and cesspools) than from the residential area with moderate-density on-site wastewater disposal 

(septic systems only), although the converse is apparent for base 

flow in those two areas, which possibly could be related to differences in soil properties or other physical properties in the two 

areas or in differences in retention/degradation rates or in maintenance and age of the cesspools relative to the septic systems 

or be an artifact of variable recovery and detection rates in laboratory analyses. Depth to water in the residential area with 

high-density on-site wastewater disposal (about 18 and 24 ft in 

two wells with water-level data) tended to be less than in the 

residential area with moderate-density on-site wastewater disposal (about 41 to 64 ft in three wells) (table 8 at the back of the 

report). Additional studies would be needed to determine the 

role of soil properties, depth to water, and type of on-site disposal system on the transport of organic wastewater compounds 

to ground water.

Enterococci and fecal coliform bacteria do not appear to be 

independent indicators of the effects of on-site wastewater disposal on ground-water and base-flow water quality, because 

elevated concentrations of bacteria were measured in samples 

from all land uses in the pilot study.

Comparison to Results from Previous Studies

As part of a previous stream assessment for Broad Run, 

base-flow and biological samples were collected at three sites 

along the main stem of Broad Run in the period 1999 to 2002 

(Cinotto and others, 2005). The data from these three sites on 

the upper, middle, and lower reaches of the Broad Run, which 

integrate the effects of all land uses in the drainage area, showed 

that base-flow concentrations of nitrate ranged from about 2.1 

to 2.8 mg/L as N and generally were slightly higher in the upper 

reach than in the middle or lower reaches. The main-stem concentrations of nitrate, chloride (19.2 to 22.6 mg/L), and boron 

(16 to 38 mg/L) were higher or slightly higher than concentrations of those constituents at a background reference site in 

Chester County (Cinotto and others, 2005, p. 40). The biological (benthic macroinvertebrates) data indicate that water quality 

in the main stem of Broad Run was good but slightly affected, 

because organisms intermediate in pollution tolerance were 

present (Cinotto and others, 2005, p. 40). Compared to the 

main-stem concentrations of nitrate, chloride, and boron measured in 1999-2002, concentrations of those constituents in base 

flow in most tributaries of the current study in 2005 were similar or higher. Nitrate concentrations were highest in tributaries 

draining an agricultural area (5.7 to 6.4 mg/L as N) and residential areas with on-site wastewater disposal (septic systems and 

(or) cesspools) (3.8 to 6.6 mg/L as N) in base flow in 2005. 

Chloride concentrations were highest in tributaries draining 

predominantly residential areas and ranged from 21 to 65 mg/L 

for base flow in 2005. Boron concentrations were highest in 

tributaries draining residential areas with on-site wastewater 

disposal and ranged from 14 to 90 μg/L for base flow in 2005.

As part of an assessment of the role of nonpoint sources on 

water quality in the Christina River Basin, base-flow and stormflow samples were collected in 1998 from site 01480637 (fig. 3) 

on a tributary to Broad Run that drains an area of predominantly 

residential land with septic systems (Senior and Koerkle, 

2003a; Senior and Koerkle, 2003b). Selected sub-basins with a 

predominant land use were instrumented for flow monitoring 

and water-quality sample collection. These data showed that 

nitrate concentrations in base flow from the residential area 

with septic systems (3 to 5 mg/L as N) were higher than in base 

flow from sewered residential, forested, and urban areas (0.5 to 

2 mg/L as N) but somewhat lower than from agricultural areas 

(3.5 to 6 mg/L) of the Christina River Basin. 

In an evaluation of water quality of West Valley Creek 

Basin, which is about 2 mi east of the Broad Run watershed of 

this study, base-flow concentrations of nitrate were about 

3 mg/L as N in tributaries draining residential areas with septic 

systems (Senior and others, 1997, p. 81-83). These residential 

areas are underlain by the same or similar rocks as those that 

underlie the Broad Run watershed, and the associated nitrate 

concentrations in base flow are similar but slightly lower than 

those measured in base flow in 2005 from the residential areas 

with septic systems (3.8 to 6.3 mg/L as N) in the current study. 

Wells in other areas possibly affected by on-site wastewater disposal were sampled in 2000 and 2002 as part of an ongo-
30 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

ing ground-water-quality monitoring program in Chester 

County, Pa., conducted by USGS in cooperation with the Chester County Health Department and Chester County Water 

Resources Authority. In 2000, samples from 6 wells in areas 

with different types of on-site wastewater disposal (table 6) 

were analyzed for major ions, nutrients, boron, selected antibiotics, human drugs, hormones, and wastewater compounds as 

part of a national reconnaissance for which 47 ground-water 

samples were collected by USGS nationwide (Barnes and others, 2005). In 2002, samples from six wells in areas with either 

drip or spray-irrigation on-site wastewater disposal (table 6) 

were analyzed for major ions, nutrients, boron, selected antibiotics, and wastewater compounds. Results of the 2000 and 2002 

sampling of 12 wells indicate ground-water quality was 

affected by anthropogenic constituents: nitrate concentrations 

generally were above the natural background of about 1 mg/L 

and ranged up to 12 mg/L as N; boron concentrations above natural background (greater than about 20 to 30 μg/L) and as high 

as 250 μg/L were measured in samples from 3 wells; chloride 

concentrations above natural background (greater than 10 to 

20 mg/L) were measured in samples from 10 wells; 18 wastewater compounds, 4 pesticides or pesticide degradates, and 1 

antibiotic (sulfamethoxole) were detected at low concentrations, with at least of 1 of these compounds detected in samples 

from 11 wells. The highest measured concentrations of boron 

(250 μg/L) and the antibiotic sulfamethoxole (0.37 μg/L) were 

in a sample from a monitor well at a drip-irrigation site. Several 

of the wastewater compounds detected in the 2000 and 2002 

ground-water samples, including phenol and DEET, also were 

detected in base flow and ground water in the Broad Run watershed in 2005 (tables 5 and 6).

Summary and Conclusions

On-site wastewater disposal has the potential to introduce 

contaminants into ground water and subsequently, by groundwater discharge, to streams. In Chester County, Pa., and other 

rural areas undergoing development, the change in land use 

consists of residential and commercial uses replacing forested 

and agricultural uses. In many of the areas being developed, residential wastewater is disposed of on-site. In 2005, the U.S. 

Geological Survey, in cooperation with the Chester County 

Water Resources Authority and the Chester County Health 

Department, conducted a pilot study of the effect of residential 

on-site wastewater disposal on stream base-flow and groundwater quality based on reconnaissance-level data. 

The Broad Run watershed drains about 7.1 mi2 in central 

Chester County. The area is underlain by Paleozoic and older 

metamorphic rocks (primarily schist and gneiss), which form 

fractured-rock aquifers. Soils are generally permeable. Depth to 

water typically varies by topography; depths to water are 

greater under hilltops than on slopes or in valleys and can range 

from 1 to 86 ft below land surface. Ground-water levels and 

base flow fluctuate seasonally because of changes in net 

recharge rates; depth to water is greatest in the fall and least in 

the spring. Ground-water discharge to streams (base flow) comprises about 80 percent of streamflow in Broad Run. 

Sites selected for base-flow and ground-water sampling 

were in tributary areas predominantly covered by one land use. 

Land uses in tributary areas included row-crop agriculture, residential with sewers, moderate-density residential (lot sizes 1 to 

2 acres or greater) with on-site wastewater disposal (septic systems), and high-density residential (village) with on-site wastewater disposal (cesspools and septic systems). Data were collected for a preliminary assessment of potential effects of onsite wastewater disposal on ground-water and base-flow water 

quality and were not intended to support statistical analyses. 

Because of limited data and lack of statistical analysis, conclusions should be considered preliminary and results interpreted 

with caution. 

Stream samples under base-flow conditions were collected 

twice at 8 sites and once at 2 other sites, and ground-water samples were collected once at 10 sites (8 wells and 2 springs) in the 

period from May to September 2005 (fig. 4). The sampling 

times were selected to collect stream samples under high baseflow (May-June 2005) and low base-flow (September 2005) 

conditions to determine if water quality was affected by hydrologic conditions. The ground-water samples were collected in 

mid-June 2005 to approximately represent ground-water quality at the time of the late May base-flow sampling. Streamflow 

in May and September 2005 in the study area was probably 

below average for those months. Samples were analyzed for 

dissolved major ions, nutrients, boron, manganese, iron, 

selected organic wastewater compounds, and bacteria.

Nitrate, chloride, and boron were considered possible indicators of wastewater on ground-water and base-flow quality, 

and concentrations of all three constituents were relatively elevated in the residential areas with on-site wastewater disposal. 

Concentrations of these constituents were more variable in 

ground-water samples than in base-flow samples. Concentrations of nitrate generally were higher in ground-water and baseflow samples from the agricultural and residential areas with 

on-site wastewater disposal than in the residential area with 

sewers. Nitrate concentrations of 10 mg/L as N, exceeding the 

USEPA MCL of 10 mg/L as N in drinking water, were measured in a ground-water sample from a well in the residential 

area with high-density on-site wastewater disposal. Base-flow 

concentrations of nitrate in the residential areas with on-site 

wastewater disposal ranged from 2 to 6.6 mg/L as N. Concentrations of chloride were higher in ground-water and base-flow 

samples from the residential areas (with on-site wastewater disposal and with sewers) than in the agricultural area. Chloride 

concentrations up to 373 mg/L, exceeding the USEPA SMCL of 

250 mg/L in drinking water, were measured in a ground-water 

sample from a well in the residential area with septic systems. 

Concentrations of boron were higher in ground-water and baseflow samples from the residential areas with on-site wastewater 

disposal than in the residential area with sewers and the agricultural area. 
Summary and Conclusions 31

Table 6. Results of laboratory analysis for nitrate, chloride, boron, and selected wastewater compounds in samples collected from 12 

wells in summer 2000 or summer 2002 in areas possibly affected by on-site wastewater disposal, Chester County, Pennsylvania

[mg/L as N; milligrams per liter as nitrogen; mg/L, milligrams per liter; μg/L, micrograms per liter; <, less than; E, estimated value less than method reporting level; M, measured value for compound detected but not quantifiable below method reporting level]

U.S. 

Geological 

Survey 

local well 

number

Date of 

sample Possible waste source

Ground-water sample concentrations

Nitrate

(mg/L as 

N)

1 Chloride Boron Wastewater compounds

(mg/L) (μg/L) (μg/L) 

Parameter 

code

Summer 2000

CH-75 8/8/2000

CH-1281 8/7/2000

CH-3331 8/9/2000

CH-3516 8/24/2000

CH-4413 8/24/2000

CH-4730 8/3/2000

Summer 2002 

CH-410 7/29/2002

CH-5178 7/31/2002

CH-6653 8/1/2002

CH-6654 8/5/2002

CH-6655 8/6/2002

CH-6656 8/7/2002

Treated sewage effluent applied by 

spray irrigation to land

Cow manure -pasture, crop land and 

human septic system

Human septic system

Large-animal veterinary center and 

human septic system

Large-animal veterinary center and 

human septic system

Spent compost from mushroom operations and human septic systems

Treated sewage effluent applied by 

spray irrigation to land and human 

septic effluent

Treated sewage effluent applied by 

spray irrigation to land

Treated sewage effluent applied by 

spray irrigation to land

Treated sewage effluent applied by 

drip irrigation to land

Treated sewage effluent applied by 

spray irrigation to land

 Treated sewage effluent applied by 

spray irrigation to land

4.75

9.93

5.98

11.1

5.01

11.8

<.05

1.61

3.46

7.79

3.80

5.35

33

18

34

34

59

52

47

66

6

91

62

88

<16

<16

67

17

<16

<16

30

20

20

250

90

20

E0.086 Octylphenol, monoethoxy

E0.083 Octylphenol, monoethoxy 

0.563 bisphenol A2

E0.348 phenol

0.099 bisphenol A2

0.04 sulfamethoxole3

2.21 bisphenol A2

0.01 sulfamethoxole3

E0.031 tri(2-chloroethyl) phosphate

E0.047 caffeine

E.1 acetophenone

M benzophenone

E0.1 DEET

0.6 phenol

E0.1 triphenylphosphate4

E0.1 tri (2-butoxy)phosphate

0.05 sulfamethoxole3

E0.1 AHTN

M metolachlor

M DEET

E0.1 tri (2-chloroethyl) phosphate

E0.2 Tri(dichloroisopropyl)phosphate 

0.37 sulfamethoxole3

M DEET

M tri (2-chloroethyl) phosphate

M Tri(dichloroisopropyl)phosphate 

0.06 sulfamethoxole3

5 E0.1 bromoform

M metalaxyl6

M triclosan7

61706

61706

62069

34466

62069

62069

62087

50305

62064

62067

62082

34466

62092

62093

62065

39415

62082

62087

62088

62082

62087

62088

34288

50359

62090

1Includes selected pharmaceuticals; if compound not listed in table 5, use listed in footnote of this table.

2

Polycarbonate resins manufacture, antioxidant, flame retardant, plasticizer.

3

Antibiotic.

4Plasticizer, flame retardant.

5

Wastewater ozonation product.

6

Pesticide.

7Disinfectant.
32 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Organic wastewater compounds were detected at low concentrations in ground-water and base-flow samples from the 

study area, indicating that the effects of on-site wastewater disposal is not limited to an increase in concentrations of nitrate, 

boron, and chloride. Of the 62 compounds in the emerging contaminant organic wastewater analysis, 30 different organic 

wastewater compounds were detected at low levels. More compounds were detected in base-flow samples than in groundwater samples. Of the ground-water samples, more compounds 

were detected in samples from springs than from wells. The difference in number of detections among base flow, springs, and 

well samples suggests the presence of shallow ground-water 

flowpaths. Of the well-water samples, more compounds generally were detected in samples from wells in the residential areas 

with high-density on-site wastewater disposal than elsewhere. 

Of the base-flow samples collected in May-June 2005, the largest number of organic wastewater compounds (10 to 14 compounds) were detected in samples from sites in the residential 

area with moderate density on-site wastewater disposal (septic 

systems), and the fewest were in samples from the sewered residential area. Base-flow samples from the site in the agricultural 

area had more compounds than base-flow samples from the residential area with high-density on-site wastewater disposal.

Bacteria were detected in samples from one well and two 

springs and in all base-flow samples. Enterococci and fecal 

coliform bacteria do not appear to be independent indicators of 

on-site wastewater disposal on ground-water and base-flow 

water quality, because elevated concentrations of bacteria were 

measured in samples from all land uses in the pilot study.

Seasonal base-flow samples showed some differences. 

Base flow in September 2005 was about 25 percent of base flow 

in May 2005, and in September, two of the 10 stream sites were 

dry. Despite the decrease in streamflow, concentrations of most 

major ions in base flow remained relatively constant from May 

to September 2005. Generally, the concentrations of most major 

ions in September base-flow samples were similar or slightly 

(commonly about 5 to 20 percent) higher than concentrations in 

May base-flow samples. Nitrate concentrations in base-flow 

samples were about 10 percent lower in September than in May 

2005, which may be related to seasonal differences in nutrient 

uptake by algae in the stream. The concentrations of boron and 

of bacteria, however, did change generally by more than 20 percent in base-flow samples from May to September 2005. The 

concentrations of boron in base-flow samples were two to three 

times higher in September than in May 2005 and were not 

accompanied by comparable increases of other constituents of 

probable anthropogenic origin, such as chloride. The sites with 

the highest concentrations of boron in base flow in September 

2005 also had the highest concentrations of boron in base flow 

in May 2005. The number and concentrations of the analyzed 

emerging contaminant organic wastewater compounds differed 

in the May-June and the September 2005 samples. More compounds were detected in base-flow samples collected in MayJune 2005 than in base-flow samples collected in September 

2005, suggesting seasonal factors such as higher springtime 

ground-water levels may affect base-flow quality. Twenty-one 

organic wastewater compounds were detected in base-flow 

samples collected in May-June 2005 and 14 compounds were 

detected in base-flow samples collected in September 2005. 

Eight compounds were detected in both May-June and September 2005 base-flow samples, including phenol, methyl salicylate, camphor, para-Cresol, DEET, metolachlor, phenanthrene, 

and caffeine. Bacteria concentrations in base-flow samples 

were greater in September 2005 compared to May 2005. 

Enterococci concentrations were greater by one to two orders of 

magnitude, and fecal coliform concentrations were similar 

(except at two sites where the September concentrations were 

two orders of magnitude greater than the May concentrations). 

Bacteria concentrations in streams commonly are greatest during the warmest months of the year, from June to September in 

Chester County, Pa.

Comparison of results of the pilot study in and near Broad 

Run watershed to other studies in Chester County, Pa., and elsewhere indicates that some of the same wastewater compounds 

were detected and elevated concentrations of nitrate, boron, and 

chloride were measured in ground water in areas of on-site 

wastewater disposal. The combination of relatively elevate 

nitrate, boron, and chloride concentrations appear to be an indicator of the presence of wastewater in ground water and associated base flow. Concentrations of nitrate in base flow in drainage areas of residential land uses with on-site wastewater 

disposal in these studies ranged from to 3 to more than 6 mg/L 

as N and were higher than in forested areas or in residential 

areas with sewers.

Acknowledgments

The cooperation of the Chester County Water Resources 

Authority, the Chester County Health Department, and the 

property owners in and near the Broad Run watershed who permitted collection of base-flow and ground-water samples is 

gratefully acknowledged. The assistance of Lindsay Hale, 

Elaine Gee, and Leif Olson of the U.S. Geological Survey in 

sample collection is appreciated. Bacteria analyses were coordinated through Nanette Morrone of the Chester County Health 

Department laboratory.

References Cited

Andreoli, Aldo, Bartilucci, Nicholas, Forgione, Robert, and 

Reynolds, Royal, 1979, nitrogen removal in a subsurface disposal system: Journal of Water Pollution Control Federation, 

v. 51, no. 4, p. 841-854. 

Barnes, K.K., Kolpin, D.W., Furlong, E.T., Zaugg, S.D., Meyer, 

M.T., Barber, L.B., and Focazio, M.J., 2005, Studies examine 

contaminants: Pharmaceuticals, hormones and other organic 

wastewater contaminants in ground water resources. National 

Driller Magazine v. 26, no. 3, March 2005, p. 38-39.
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Canter, L.W., and Knox, R.C., 1985, Septic tanks effects on 

ground water quality: Chelsea, Mich., Lewis Publishers, Inc. 

336 p. 

Cinotto, P.J., Reif, A.G., and Olsen, L.E., 2005, Envronmental 

setting, water budget, and stream assessment for the Broad 

Run Watershed, Chester County, Pennsylvania: U.S. Geological Survey Scientific Investigations Report 205/5156, 59 p.

Durlin, R.R., and Schaffstall, W.P., 2001, Water resources data, 

Pennsylvania, water year 2000, volume 1. Delaware River 

Basin: U.S. Geological Survey Water-Data-Report PA-00-1, 

676 p.

Durlin, R.R., and Schaffstall, W.P., 2003, Water reources data, 

Pennsylvania, water year 2002, volume 1. Delaware River 

Basin: U.S. Geological Survey Water-Data-Report PA-02-1, 

527 p.

Durlin, R.R., and Schaffstall, W.P., and Beaver, M.R., 2006, 

Water reources data, Pennsylvania, water year 2005, 

volume 1. Delaware River Basin: U.S. Geological Survey 

Water-Data-Report PA/205/1, 575 p.

Garges, J.A., 1988, Ground-water levels in the lower Paleozoic 

and Precambrian crystalline rocks, of East Bradford and West 

Bradford Townships, Chester County, Pennsylvania, July and 

August 1987: U.S. Geological Survey Water-Resources 

Investigations Report 88-4052, 1 plate, scale 1:24,000.

Hinkle, S.R., Weick, R.J., Johnson, J.M., Cahill, J.D., Smith 

S.G., and Rich, B.J., 2005, Organic wastewater compounds, 

pharmaceuticals, and coliphage in ground water receiving 

discharge from onsite wastewater treament systems near 

LaPine, Oregon: Occurrence and Implications for transport: 

U.S. Geological Survey Scientific Investigations Report 

2005-5055, 98 p.

Kolpin, D.W., Furlong, E.T., Meyer, M.T., Thurman, E.M., 

Zaugg, S.D., Barber, L.B., and Buxton, H.T., 2002, Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: A national reconnaissance: 

Environmental Science and Technology, v. 36, p. 1202-1211.

Loper, C.A., Crawford, J.K., Otto, K.L., Manning, R.L., Meyer, 

M.T., and Furlong, E.T., 2007, Concentrations of selected 

pharmaceuticals and antibiotics in south-central Pennsylvania waters, March through September 2006: U.S. Geological 

Survey Data Series 300, 101 p.

Minnesota Pollution Control Agency, 1999, Effects of septic 

systems on ground water quality - Baxter, Minnesota: St. 

Paul, Minn., Minnesota Pollution Control Agency, May 

1999, 37 p. 

Myers, D.N., and Wilde, F.D., 1997, Biological indicators: U.S. 

Geological Survey Techniques of Water-Resources Investigations, book 9, chap. A7, 38 p.

National Oceanic and Atmospheric Administration, 2005a, Climatological data, annual summary, Pennsylvania, 2005: 

National Climatic Data Center, v. 110, no. 13.

National Oceanic and Atmospheric Administration, 2005b, Climatological data, Pennsylvania, May 2005: National Climatic Data Center, v. 110, no. 5.

Pennsylvania Department of Environmental Protection, 1996, 

Pennsylvania Code, Title 25, Chapter 93, Water Quality Standards: Commonwealth of Pennsylvania, 213 p. 

Reif, A.G., 2002, Assessment of stream conditions and trends in 

biological and water-chemistry data from selected streams in 

chester County, Pennsylvania, 1981-97: U.S. Geological 

Survey Water Resources Investigations Report 02-4242, 

77 p.

Robertson, W.D., and Blowes, D.W., 1995, Major ion and trace 

metal geochemistry of an acidic septic-system plume in silt: 

Groundwater, v. 33, no. 2, p. 275-283.

Robertson, W.D., Cherry, J.A., and Sudicky, E.A., 1991 

Ground-water contamination from two small septic systems 

on sand aquifers: Groundwater, v. 29, no. 1, p. 82-92. 

Schreffler, C.L., Galeone, D.G., Veneziale, J.M., Olson, L.E., 

and O’Brien, D.L., 2005, Effects of spray-irrigated treated 

effluent on water quanty and quality, and the fate and transport of nitrogen in a small watershed, New Garden Township, 

Chester County, Pennsylvania: U.S. Geological Survey Scientific Investigations Report 2005-5043, 158 p. 

Senior, L.A., 1993, Geohydrology of, and nitrogen and chloride 

in, the glacial aquifer, Milford-Matamoras area, Pike County, 

Pennsylvania: U.S. Geological Survey Water-Resources 

Investigations Report 93-4109, 43 p. 

Senior, L.A., and Koerkle, E.H., 2003a, Simulation of streamflow and water quality in the Brandywine Creek subbasin of 

the Christina River Basin, Pennsylvania and Delaware, 1994-

98: U.S. Geological Survey Water-Resources Investigations 

Report 02-4279, 207 p.

Senior, L.A., and Koerkle, E.H., 2003b, Simulation of streamflow and water quality in the Christina River subbasin and 

overview of simulations in other subbasins of the Christina 

River Basin, Pennsylvania, Maryland, and Delaware, 1994-

98: U.S. Geological Survey Water-Resources Investigations 

Report 03-4193, 144 p.

Senior, L.A., and Sloto, R.A., 2006, Arsenic, boron, and fluoride concentrations in ground water in and near diabase intrusions, Newark Basin, southeastern Pensylvania: U.S. Geological Survey Scientific Investigations Report 2006-5261, 

105 p. 

Senior, L.A., Sloto, R.A., and Reif, A.G., 1997, Hydrogeology 

and water quality of the West Valley Creek Basin, Chester 

County, Pennsylvania: U.S. Geological Survey WaterResources Investigations Report 94-4137, 160 p. 

Sloto, R.A., 1994, Geology, hydrology, and ground-water quality of Chester County, Pennsylvania: West Chester, Pa., 

Chester County Water Resources Authority Water-Resource 

Report 2, 127 p. 

Town, D.A., 2001, Historical trends and concentrations of fecal 

coliform bacteria in the Brandywine Creek Basin, Chester 

County, Pennsylvania: U.S. Geological Survey WaterResources Investigations Report 01-4026, 46 p. 

U.S. Environmental Protection Agency, 1986, Ambient water 

quality for bacteria - 1986: U.S. Environmental Protection 

Agency EPA440/5-84-002, 18 p.
34 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

U.S. Environmental Protection Agency, 2006, 2006 Edition of 

the drinking water standards and health advisories: U.S. 

Environmental Protection Agency EPA 822-R-6/013. 

U.S. Geological Survey, variously dated, National field manual 

for the collection of water-quality data: U.S. Geological 

Survey Techniques of Water-Resources Investigations, book 

9, chaps. A1-A9, available online at

http://pubs.water.usgs.gov/twri9A. 

Vengosh, A., Heumann, K.G., Juraske, S., and Kasher, R., 

1994, Boron isotope application for tracing sources of contamination in groundwater: Environmental Science & Technology v. 28, p. 1968-1974.

Walker, W.G., Bouma, J., Keeney, D.R., and Olcott, P.G., 

1973, Nitrogen transformations during subsurface disposal of 

septic tank effluent in sands—2. Ground water 

quality: Journal of Environmental Quality, v. 2, no. 4, p. 

521-525.

Zaugg, S.D., Smith, S.G., Schroeder, M.P., Barber, L.B., and 

Burkhardt, M.R., 2002, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory---Determination of wastewater compounds by polystyrene-divinylbenzene solid-phase extraction and capillary-column gas 

chromatography/mass spectrometry: U.S. Geological Survey 

Water-Resources Investigations Report 01-4186, 37 p.

(Method ID: O-1433-01)

Zaugg, S.D., and Leiker, T.J., 2006, Review of methods performance and improvements for determining wastewater compounds (Schedule 1433): U.S. Geological Survey National 

Water Quality Technical Memorandum 2006.01.
Table 7 35

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005. (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

U.S. 

Geological 

Survey 

station 

identification 

number

Station name Date Time

Agency 

analyzing 

sample, 

code 

(00028)

Altitude of 

land 

surface

feet 

(72000)

Instantaneous 

discharge, 

ft3

/s 

(00061)

Drainage 

area, 

mi2

 

(81024)

0148063532

0148063532

0148063522

014806368

014806368

014806368

014806366

014806366

014806369

014806369

014806369

01480637

01480637

01480637

01480637

014806374

014806384

014806384

014806394

014806394

01480913

01480913

Unn Trib to Broad Run at Chestnut Ln nr Thorndale, Pa. 

Unn Trib to Broad Run at Chestnut Ln nr Thorndale, Pa. 

Unn Trib to Broad Run ab school nr Thorndale, Pa.

Unn Trib to Little Broad Run nr Romansville, Pa.

Unn Trib to Little Broad Run nr Romansville, Pa.

Unn Trib to Little Broad Run nr Romansville, Pa.

L Broad Run ab Shadyside Rd nr Romansville, Pa.

L Broad Run ab Shadyside Rd nr Romansville, Pa.

L Broad Run bl Shadyside Road near Romansville, Pa.

L Broad Run bl Shadyside Road near Romansville, Pa.

L Broad Run bl Shadyside Road near Romansville, Pa.

Little Broad Run near Marshallton, Pa.

Little Broad Run near Marshallton, Pa.

Little Broad Run near Marshallton, Pa.

Little Broad Run near Marshallton, Pa.

Outfall Trib to Broad Run ab Rt 162 nr Marshallton, Pa. 

Unnamed Tributary to Broad Run at Marshallton, Pa.

Unnamed Tributary to Broad Run at Marshallton, Pa.

Un Tr to Un Tr to WB Brandywine Cr at Marshallton, Pa. 

Un Tr to Un Tr to WB Brandywine Cr at Marshallton, Pa. 

Unn Trib to EB Brandywine Creek at Marshallton, Pa.

Unn Trib to EB Brandywine Creek at Marshallton, Pa.

5/26/2005

9/27/2005

5/26/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

9/28/2005

5/26/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

1130

1130

1230

1100

1010

1000

0830

0900

1210

0800

1100

1310

1120

1200

1201

1315

1010

0900

0900

1030

0730

0800

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

411.8

411.8

436.7

365

365

365

386.4

386.4

340.7

340.7

340.7

307.6

307.6

307.6

307.6

273.4

308.9

308.9

257.8

257.8

295

295

0.19

.04

.10

.12

.12

.01

.20

.06

.69

.52

.20

.90

.82

.24

.24

.02

.12

.03

.12

.04

.19

.01

0.27 

.27 

.24 

.21 

.21 

.21 

.11 

.11 

.49 

.49 

.49 

.6

.6

.6

.6

--

.05 

.05 

.16 

.16 

.06 

.06 
36 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

U.S. 

Geological 

Survey 

station 

identification 

number

Date

Barometric 

pressure, 

mm Hg 

(00025)

Dissolved 

oxygen, 

mg/L 

(00300)

Dissolved 

oxygen, 

percent of 

saturation 

(00301)

pH, 

water, 

unfltrd 

field, 

std units 

(00400)

pH, 

water, 

unfltrd lab, 

std units 

(00403)

Specific 

conductance, 

wat unf 

lab, 

μS/cm 

25 °C 

(90095)

Specific 

conductance, 

water, unf, 

μS/cm 

25 °C 

(00095)

Temperature, 

air, 

°C 

(00020)

Temperature, 

water, 

°C 

(00010)

Calcium 

water, 

fltrd, 

mg/L 

(00915)

Magnesium, 

water, 

fltrd, 

mg/L 

(00925)

0148063532

0148063532

0148063522

014806368

014806368

014806368

014806366

014806366

014806369

014806369

014806369

01480637

01480637

01480637

01480637

014806374

014806384

014806384

014806394

014806394

01480913

01480913

5/26/2005

9/27/2005

5/26/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

9/28/2005

5/26/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

741

748

741

749

754

753

749

753

749

755

753

749

755

753

753

741

741

748

741

748

741

748

10.0

8.7

11.0

10.5

9.7

9.6

11.0

10.0

10.3

9.0

9.0

10.6

9.0

10.0

10.0

5.8

10.5

8.5

10.7

8.6

10.4

8.3

93

88

104

98

97

92

100

96

95

94

89

100

96

103

103

57

98

86

99

89

94

83

7.2

7.4

8.0

7.5

7.3

7.8

7.1

7.3

7.0

6.8

7.2

7.2

7.2

7.5

7.5

7.3

7.1

7.2

7.5

7.5

7.0

7.2

7.5

6.6

7.8

7.4

--

5.9

7.3

6.4

7.5

--

6.2

7.2

--

6.2

6.3

7.7

7.5

6.6

7.5

6.7

7.3

6.8

217

272

292

261

--

385

215

250

239

--

271

231

--

265

266

437

427

375

220

264

155

144

221

271

295

262

281

386

216

253

245

270

276

232

255

269

269

444

408

368

225

264

155

144

15.0

--

17.5

11.0

27.5

14.0

11.0

14.0

11.5

25.5

17.5

--

25.0

22.0

22.0

20.5

14.5

--

13.5

--

13.5

--

12.3

16.2

12.8

11.4

15.5

13.7

11.3

13.4

11.8

17.6

15.2

11.7

18.4

16.6

16.6

13.8

12.2

15.5

11.7

16.8

11.2

15.3

19.1

26.3

17.9

19.5

--

32.9

9.57

11.2

16.7

--

18.4

16.4

--

19.0

19.0

61.6

24.0

23.4

14.9

18.4

12.2

12.2

10.6

12.3

12.9

12.7

--

14.1

7.82

8.13

10.3

--

10.2

8.63

--

8.62

8.83

14.2

19.1

15.4

8.20

10.0

5.49

4.31
Table 7 37

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

U.S. 

Geological 

Survey 

station 

identification 

number

Date

Potassium, 

water, 

fltrd, 

mg/L 

(00935)

Sodium, 

water, 

fltrd, 

mg/L 

(00930)

Alkalinity, 

water, flt 

inc tit 

field, 

mg/L as 

CaCO3 

(39086)

Chloride, 

water, 

fltrd, 

mg/L 

(00940)

Fluoride, 

water, 

fltrd, 

mg/L 

(00950)

Silica, 

water, 

fltrd, 

mg/L

(00955)

Sulfate, 

water, 

fltrd, 

mg/L 

(00945)

Ammonia 

water, 

fltrd, 

mg/L as N 

(00608)

Nitrite + 

nitrate

water, 

fltrd, 

mg/L as N 

(00631)

Nitrite 

water, 

fltrd, 

mg/L as N 

(00613)

Orthophosphate, 

water, 

fltrd, 

mg/L as P 

(00671)

0148063532

0148063532

0148063522

014806368

014806368

014806368

014806366

014806366

014806369

014806369

014806369

01480637

01480637

01480637

01480637

014806374

014806384

014806384

014806394

014806394

01480913

01480913

5/26/2005

9/27/2005

5/26/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

9/28/2005

5/26/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

1.07 

1.74 

1.05 

2.60 

--

2.19 

1.31 

1.25 

1.39 

--

1.44 

1.37 

--

1.46 

1.48 

2.00 

3.29 

2.74 

2.23 

2.52 

1.76 

2.12 

7.61

7.08

20.2

13.5

--

19.3

20.4

20.0

16.8

--

16.4

15.3

--

15.6

15.5

14.3

32.2

23.2

15.3

14.6

8.78

7.56

41

48

46

36

--

58

17

10

30

--

32

31

--

36

36

154

56

42

34

27

30

24

21.4

21.5

50.5

29.1

--

44.1

39.3

43.6

37.1

--

40.3

34.6

--

39.8

39.6

20.0

65.0

51.8

30.6

34.7

11.7

9.61

<0.10

<.10

<.10

<.10

--

E.07

<.10

<.10

<.10

--

<.10

<.10

--

<.10

<.10

E.08

<.10

<.10

<.10

<.10

<.10

<.10

11.3

14.7

7.2

8.7

--

12.3

5.6

5.9

8.7

--

9.3

9.1

--

9.6

9.6

16.4

11.8

12.8

14.8

17.2

14.7

16.5

11.1

9.54

14.8

24.4

--

29.6

13.0

12.4

16.4

--

16.0

15.0

--

14.7

14.5

30.7

27.4

22.5

16.8

18.3

17.4

14.7

E0.03

<.04

<.04

<.04

--

<.04

<.04

<.04

.06

--

.05

E.03

--

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

6.37

5.69

3.23

6.30

--

5.52

4.45

5.17

4.17

--

3.93

4.03

--

3.83

3.82

3.33

6.61

5.32

2.82

2.71

1.94

1.17

E0.006

<.008

E.005

.008

--

<.008

<.008

<.008

.027

--

.033

.019

--

E.005

E.004

<.008

<.008

<.008

<.008

<.008

<.008

<.008

<0.02

E.01

<.02

E.01

--

.02

E.01

<.02

<.02

--

<.02

<.02

--

E.01

E.01

<.02

E.02

.02

<.02

.03

<.02

<.02
38 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

U.S. 

Geological 

Survey 

station 

identification 

number

Date

Enterococi, 

m-E MF, 

water, 

col/100 mL 

(31649)

Fecal 

coliform, 

M-FC 

0.7μ MF 

col/100 mL 

(31625)

Boron, 

water, 

fltrd, 

μg/L 

(01046)

Iron, 

water, 

fltrd, 

μg/L

(01046)

Manganese, 

water, 

fltrd, 

μg/L

(01056)

1,4-Dichlorobenzene 

water, 

fltrd, 

μg/L

(34572)

1-Methylnaphthalene, 

water, 

fltrd, 

μg/L 

(62054)

2,6-Dimethylnaphthalene, 

water, 

fltrd, 

μg/L

(62055)

2-Methylnaphthalene, 

water, 

fltrd, 

μg/L 

(62056)

3-betaCoprostanol,

water, 

fltrd, 

μg/L 

(62057)

3-Methyl1Hindole, 

water, 

fltrd, 

μg/L

(62058)

0148063532

0148063532

0148063522

014806368

014806368

014806368

014806366

014806366

014806369

014806369

014806369

01480637

01480637

01480637

01480637

014806374

014806384

014806384

014806394

014806394

01480913

01480913

5/26/2005

9/27/2005

5/26/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

9/28/2005

5/26/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

570

2,900

960

60

--

350

60

610

200

--

4,100

190

--

7,500

9,200

60

80

3,700

10

8,000

20

1,480

310

330

110

10

--

48

40

94

190

--

130

60

--

34

30

10

140

410

10

2700

<1

620

8.5

26

E6.4

33

--

90

28

47

29

--

48

29

--

49

49

7.5

44

55

14

31

11

31

16

17

E4

<6

--

6

7

E3

43

--

74

19

--

13

10

12

<6

E5

7

E6

28

106

39.1

12.2

4.8

3.7

--

4.5

5.4

.8

51.9

--

24.9

8.7

--

7.6

7.5

17.5

2.1

1.2

4.6

3.1

37.1

55.1

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

M

<.5

--

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<2

<2

<2

--

<2

<2

<2

<2

--

<2

<2

--

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

M

<1

<1

--

<1

M

<1

<1

--

M

<1

--

M

<1

<1

<1

<1

<1

<1

<1

<1

<1
Table 7 39

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

U.S. 

Geological 

Survey 

station 

identification 

number

Date

3-tertButyl4-hydroxyanisole 

water, 

fltrd, 

μg/L

(62059)

4-Cumylphenol, 

water, 

fltrd, 

μg/L 

(62060)

4-Octylphenol, 

water, 

fltrd, 

μg/L 

(62061)

4-Nonylphenol, 

water, 

fltrd, 

μg/L

(62085)

4-tertOctylphenol, 

water, 

fltrd, 

μg/L 

(62062)

5-Methyl1H-benzotriazole, 

water, 

fltrd, 

μg/L

(62063)

9,10-

Anthraquinone 

water, 

fltrd, 

μg/L 

(62066)

Acetophenone 

water, 

fltrd, 

μg/L

(62064)

AHTN, 

water, 

fltrd, 

μg/L 

(62065)

Anthracene, 

water, 

fltrd, 

μg/L 

(34221)

Benzo-

[a]-

pyrene, 

water, 

fltrd, 

μg/L 

(34248)

0148063532

0148063532

0148063522

014806368

014806368

014806368

014806366

014806366

014806369

014806369

014806369

01480637

01480637

01480637

01480637

014806374

014806384

014806384

014806394

014806394

01480913

01480913

5/26/2005

9/27/2005

5/26/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

9/28/2005

5/26/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

<5

<5

<5

--

<5

<5

<5

<5

--

<5

<5

--

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<1

<1

<1

--

<1

<1

<1

<1

--

<1

<1

--

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

M

<1

<1

--

<1

<1

<1

<1

--

<1

<1

--

<1

<1

<1

<1

M

<1

<1

<1

M

<1

<5

E1

<5

--

<5

<5

<5

M

--

<5

<5

--

<5

M

M

<5

<5

M

<5

E1

<5

<5

<1

<1

<1

--

<1

<1

<1

<1

--

<1

<1

--

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<2

<2

<2

--

<2

<2

<2

<2

--

<2

<2

--

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

M

<.5

<.5

<.5

--

M

<.5

--

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

M

<.5

--

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5
40 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

U.S. 

Geological 

Survey 

station 

identification 

number

Date

Benzophenone 

water, 

fltrd, 

μg/L

(62067)

betaSitosterol, 

water, 

fltrd, 

μg/L 

(62068)

betaStigmastanol, 

water, 

fltrd, 

μg/L 

(62086)

Bisphenol A, 

water, 

fltrd, 

μg/L 

(62069)

Bisphenol Ad3 

sur Sch 

2033 & 

8033, 

water, fltrd, 

pct rcv 

(99583)

Bromacil, 

water, 

fltrd, 

μg/L 

(04029)

Caffeine, 

water, 

fltrd, 

μg/L 

(50305)

Caffeine13C 

sur Sch 

2033 & 

8033, 

water, fltrd, 

pct rcv 

(99584)

Camphor 

water, 

fltrd, 

μg/L 

(62070)

Carbaryl, 

water, 

fltrd 

0.7u GF 

μg/L 

(82680)

Carbazole, 

water, 

fltrd, 

μg/L 

(62071)

0148063532

0148063532

0148063522

014806368

014806368

014806368

014806366

014806366

014806369

014806369

014806369

01480637

01480637

01480637

01480637

014806374

014806384

014806384

014806394

014806394

01480913

01480913

5/26/2005

9/27/2005

5/26/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

9/28/2005

5/26/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<2

<2

<2

--

<2

<2

<2

<2

--

<2

<2

--

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

--

<2

<2

<2

<2

--

<2

<2

--

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

--

--

--

--

<1

--

--

--

--

<1

--

--

<1

--

--

--

--

--

--

--

M

--

13.6

.0

27.6

--

.0

.0

72.4

.0

--

.0

.0

--

.0

16.3

.0

22.1

24.9

.0

25.0

.0

25.4

.0

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

M

M

<.5

<.5

--

<.5

<.5

--

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

81.0

85.7

83.6

--

77.8

110

86.1

100

--

76.2

94.5

--

84.3

91.6

96.0

81.9

80.9

90.0

80.0

87.0

81.3

86.7

<0.5

M

<.5

--

M

<.5

<.5

<.5

--

M

M

--

M

<.5

M

<.5

<.5

M

<.5

M

<.5

M

<1

<1

<1

--

<1

<1

<1

<1

--

<1

<1

--

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5
Table 7 41

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

U.S. 

Geological 

Survey 

station 

identification 

number

Date

Chlorpyrifos 

water, 

fltrd, 

μg/L 

(38933)

Cholesterol, 

water, 

fltrd, 

μg/L 

(62072)

Cotinine, 

water, 

fltrd, 

μg/L 

(62005)

DecaFbiphenl 

sur Sch 

2033 & 

8033, 

water, fltrd, 

pct rcv 

(99585)

DEET, 

water, 

fltrd, 

μg/L 

(62082)

Diazinon, 

water, 

fltrd, 

μg/L

(39572)

Diethoxynonylphenol, 

water, 

fltrd, 

μg/L 

(62083)

Diethoxyoctylphenol, 

water, 

fltrd, 

μg/L 

(61705)

D-Limonene, 

water, 

fltrd, 

μg/L 

(62073)

Ethoxyoctylphenol,

water,

fltrd 

μg/L

(61706)

Fluoranthene 

water, 

fltrd, 

μg/L 

(34377)

0148063532

0148063532

0148063522

014806368

014806368

014806368

014806366

014806366

014806369

014806369

014806369

01480637

01480637

01480637

01480637

014806374

014806384

014806384

014806394

014806394

01480913

01480913

5/26/2005

9/27/2005

5/26/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

9/28/2005

5/26/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

M

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<2

<2

<2

--

<2

<2

<2

<2

--

<2

<2

--

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<1.00

<1.00

<1.00

--

<1.00

<1.00

<1.00

<1.00

--

<1.00

<1.00

--

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

78.7

56.3

75.7

--

61.2

86.2

76.8

69.3

--

48.7

74.7

--

62.1

88.5

67.4

74.1

73.4

48.8

61.5

68.1

64.3

51.7

<0.5

<.5

<.5

--

M

M

M

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<5

<5

<5

--

<5

<5

<5

<5

--

<5

<5

--

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<1

<1

<1

--

<1

<1

<1

<1

--

M

<1

--

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<1

<1

<1

--

<1

<1

<1

<1

--

M

<1

--

M

<1

<1

<1

<1

<1

<1

<1

<1

<1

<0.5

<.5

<.5

--

<.5

M

<.5

<.5

--

<.5

M

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M
42 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

U.S. 

Geological 

Survey 

station 

identification 

number

Date

Fluoranthene -

d10, 

sur Sch 

20/8033 

water, fltrd, 

pct rcv 

(99586)

HHCB, 

water, 

fltrd, 

μg/L 

(62075)

Indole, 

water, 

fltrd, 

μg/L 

(62076)

Isoborneol, 

water, 

fltrd, 

μg/L 

(62077)

Isophorone 

water, 

fltrd, 

μg/L 

(34409)

Isopropylbenzene 

water, 

fltrd, 

μg/L 

(62078)

Isoquinoline, 

water, 

fltrd, 

μg/L 

(62079)

Menthol 

water, 

fltrd, 

μg/L 

(62080)

Metalaxyl, 

water, 

fltrd, 

μg/L 

(50359)

Methyl 

salicylate, 

water, 

fltrd, 

μg/L 

(62081)

Metolachlor, 

water, 

fltrd, 

μg/L 

(39415)

0148063532

0148063532

0148063522

014806368

014806368

014806368

014806366

014806366

014806369

014806369

014806369

01480637

01480637

01480637

01480637

014806374

014806384

014806384

014806394

014806394

01480913

01480913

5/26/2005

9/27/2005

5/26/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

5/25/2005

6/10/2005

9/28/2005

9/28/2005

5/26/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

5/26/2005

9/27/2005

72.7

85.7

74.7

--

72.1

95.1

78.9

97.6

--

70.7

95.5

--

75.9

94.0

97.0

73.5

76.1

84.1

73.8

87.9

72.6

85.7

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

M

<.5

<.5

--

M

<.5

--

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M

<0.5

<.5

--

M

<.5

<.5

<.5

--

M

<.5

--

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M

<0.5

<.5

--

M

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

--

<.5

<.5

<.5

<.5

--

<.5

<.5

--

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

E.1

<.5

--

M

M

<.5

M

--

<.5

M

--

M

<.5

M

<.5

<.5

M

<.5

M

<.5

E.1

<0.5

<.5

<.5

--

M

E.1

<.5

<.5

--

M

<.5

--

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5
Table 7 43

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

Tri- Penta- Tetra- Tri- U.S. Naphth- Phenan- Prome- butyl p-Cresol, chloro- Phenol, Pyrene, chloro- bromo- Geological alene, threne, ton, phos- water, phenol, water, water, ethene, methane Survey water, water, water, phate, Date fltrd, water, fltrd, fltrd, water, water, station fltrd, fltrd, fltrd, water, 

μg/L fltrd, μg/L μg/L fltrd, fltrd, identification μg/L μg/L μg/L fltrd, (62084) μg/L (34466) (34470) μg/L μg/L number (34443) (34462) (04037) μg/L (34459) (34476) (34288) (62089)

0148063532 5/26/2005 <0.5 <1 -- <0.5 E0.3 <0.5 <0.5 <0.5 <0.5 <0.5

0148063532 9/27/2005 <.5 M -- <.5 <.5 <.5 <.5 <.5 <.5 <.5

0148063522 5/26/2005 <.5 <1 -- <.5 E.2 <.5 <.5 <.5 <.5 <.5

014806368 5/25/2005 -- -- -- -- -- -- -- -- -- --

014806368 6/10/2005 <.5 M <2 <.5 E.2 <.5 <.5 <.5 <.5 <.5

014806368 9/28/2005 M M -- M 1.4 <.5 M <.5 <.5 <.5

014806366 5/25/2005 <.5 <1 -- <.5 E.2 <.5 <.5 <.5 <.5 <.5

014806366 9/28/2005 <.5 <1 -- <.5 1.0 <.5 <.5 <.5 <.5 <.5

014806369 5/25/2005 -- -- -- -- -- -- -- -- -- --

014806369 6/10/2005 <.5 M <2 M E.1 <.5 <.5 <.5 <.5 <.5

014806369 9/28/2005 M <1 -- M 1.1 <.5 M <.5 <.5 <.5

01480637 5/25/2005 -- -- -- -- -- -- -- -- -- --

01480637 6/10/2005 <.5 M <2 M E.5 <.5 <.5 <.5 <.5 <.5

01480637 9/28/2005 <.5 M -- <.5 .6 <.5 <.5 <.5 <.5 <.5

01480637 9/28/2005 <.5 M -- <.5 .6 <.5 <.5 <.5 <.5 <.5

014806374 5/26/2005 <.5 <1 -- <.5 E.1 <.5 <.5 <.5 <.5 <.5

014806384 5/26/2005 <.5 <1 -- <.5 E.3 <.5 <.5 <.5 <.5 <.5

014806384 9/27/2005 <.5 <1 -- <.5 E.1 <.5 <.5 <.5 <.5 <.5

014806394 5/26/2005 <.5 <1 -- <.5 E.1 <.5 <.5 <.5 <.5 <.5

014806394 9/27/2005 <.5 <1 -- <.5 E.2 <.5 <.5 <.5 <.5 <.5

01480913 5/26/2005 <.5 <1 -- <.5 <.5 <.5 <.5 <.5 <.5 <.5

01480913 9/27/2005 <.5 <1 -- <.5 E.1 <.5 M <.5 <.5 <.5
44 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Table 7. Results of laboratory analysis of base-flow samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, May-June and September 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

Tri- Tris (2- Tris (2- Tris (di Tri- Sample U.S. Triclo- phenyl butoxy- chloro- chloro- ethyl volume, Geological san, phos- ethyl) ethyl) i-Pr) citrate wastewater Survey water, phate, phosphate, phosphate, phosphate, Date water, method station fltrd, water, water, water, water, fltrd, water, fltrd, identification μg/L fltrd, fltrd, fltrd, fltrd, 

μg/L mL number (62090) μg/L μg/L μg/L μg/L (62091) (99587) (62092) (62093) (62087) (62088)

0148063532 5/26/2005 <1 <0.5 <0.5 <0.5 E0.1 M 798

0148063532 9/27/2005 <1 <.5 <.5 <.5 <.5 <0.5 868

0148063522 5/26/2005 <1 <.5 <.5 <.5 <.5 <.5 826

014806368 5/25/2005 -- -- -- -- -- -- --

014806368 6/10/2005 <1 <.5 <.5 <.5 <.5 <.5 786

014806368 9/28/2005 <1 <.5 <.5 <.5 <.5 <.5 838

014806366 5/25/2005 <1 <.5 <.5 <.5 <.5 <.5 866

014806366 9/28/2005 <1 <.5 <.5 <.5 <.5 <.5 797

014806369 5/25/2005 -- -- -- -- -- -- --

014806369 6/10/2005 <1 <.5 <.5 <.5 <.5 <.5 870

014806369 9/28/2005 <1 <.5 <.5 <.5 <.5 <.5 846

01480637 5/25/2005 -- -- -- -- -- -- --

01480637 6/10/2005 <1 <.5 <.5 <.5 <.5 <.5 821

01480637 9/28/2005 <1 <.5 <.5 <.5 <.5 <.5 525

01480637 9/28/2005 <1 <.5 <.5 <.5 <.5 <.5 887

014806374 5/26/2005 <1 <.5 <.5 <.5 <.5 <.5 --

014806384 5/26/2005 <1 <.5 <.5 <.5 <.5 M 845

014806384 9/27/2005 <1 <.5 <.5 <.5 <.5 <.5 798

014806394 5/26/2005 <1 <.5 <.5 <.5 <.5 M 811

014806394 9/27/2005 <1 <.5 <.5 <.5 <.5 <.5 874

01480913 5/26/2005 <1 <.5 <.5 <.5 <.5 M 785

01480913 9/27/2005 <1 <.5 <.5 <.5 <.5 <.5 891
Table 8 45

Table 8. Results of laboratory analysis of ground-water samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, June 2005. (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

Local 

identifier

U.S. Geological 

Survey 

station 

identification 

number

Date Time

Agency 

analyzing 

sample, 

code 

(00028)

Depth of 

well, 

feet below 

LSD 

(72008)

Depth to 

water level, 

feet below 

LSD 

(72019)

Altitide of 

land 

surface 

feet 

(72000)

Flow rate, 

instantaneous 

gal/min 

(00059)

Pump or 

flow period 

prior to 

sampling, 

minutes 

(72004)

Barometric 

pressure, 

mm Hg 

(00025)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

395807075450201

395815075435501

395807075432201

395752075424801

395735075425301

395654075405001

395651075405601

395642075403801

395701075404401

395715075404401

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

0830

1210

1020

1050

1130

0850

1120

1000

1130

1140

80020

80020

80020

80020

80020

80020

80020

80020

80020

80020

--

--

--

128

430

--

92

--

150

--

--

38.25

64.03

41.34

62.95

--

--

--

24.03

17.89

425

557

535

398

369

395

390

290

405

354

0.25

1.5

1.5

1.5

1.5

1.2

1.5

.2

1.5

1.5

27

32

58

66

51

52

35

21

61

53

748

752

745

751

757

756

746

753

750

750

Local 

identifier Date

Dissolved 

oxygen, 

mg/L 

(00300)

Dissolved 

oxygen, 

percent of 

saturation 

(00301)

pH, 

water, 

unfltrd field, 

std units 

(00400)

pH, 

water, 

unfltrd lab, 

std units 

(00403)

Specific 

conductance, 

wat unf lab, 

μS/cm 

25 degC 

(90095)

Specific 

conductance, 

wat unf, 

μS/cm 

25 degC 

(90095)

Temperature, 

air, 

deg C 

(00020)

Temperature, 

water, 

deg C 

(00010)

Calcium, 

water, 

fltrd, 

mg/L 

(00915)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

8.3

10.1

9

8.5

2.7

5.8

9.1

8.9

5.3

9.7

78

94

87

81

26

55

87

83

52

93

5.7

5.6

5.2

5.8

6.8

5.9

5.3

5.9

5.3

5.5

5.9

5.8

5.6

6.1

7.2

6.3

5.6

6.2

5.8

6

230

295

192

831

148

248

340

223

1350

181

244

312

207

871

152

264

371

239

1340

189

23.5

18.5

23.5

17

22.5

10

27.5

28.5

28

29.5

12.4

11.9

13.8

13.3

14

12.7

13.3

12.1

14.2

13.7

18.3

8.69

8.82

59.9

17.6

17.3

21

15.6

80.5

15.1
46 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Table 8. Results of laboratory analysis of ground-water samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, June 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

Local 

identifier Date

Magnesium, 

water, 

mg/L 

(00925)

Potassium, 

water, 

fltrd, 

mg/L 

(00935)

Sodium, 

water, 

fltrd, 

mg/L 

(00930)

Alkalinity, 

water,

fltrd, 

inc tit field, 

mg/L as CaCO3 

(39086)

Chloride, 

water, 

fltrd, 

mg/L 

(00940)

Fluoride, 

water, 

fltrd, 

mg/L 

(00950)

Silica, 

water, 

fltrd, 

mg/L 

(00955)

Sulfate, 

water, 

fltrd, 

mg/L 

(00945)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

8.39

10.6

6.33

21.1

3.94

13.5

8.47

8.93

52.7

7.6

2.16

1.11

1.45

2.4

1.34

1.61

2.42

2.32

4.8

3.56

10.3

35.5

16.8

72.4

5.59

12.9

28.8

13.6

86.1

6.11

18

19

9

29

43

47

13

35

26

27

26.1

63.6

32.3

242

4.91

27.4

66.5

30.4

373

5.37

<0.10

<.10

<.10

<.10

E.08

E.06

<.10

<.10

E.06

<.10

11.7

5.1

5.5

14.8

17

27.3

15.8

17.3

17.6

13

17.9

19.2

12.9

6.45

17.8

13.6

12.8

19

36.1

22.4

Local 

identifier Date

Ammonia 

water, 

fltrd, 

mg/L as N 

(00608)

Nitrite + 

nitrate

water fltrd, 

mg/L as N 

(00631)

Nitrite 

water, 

fltrd, 

mg/L as N 

(00613)

Orthophosphate, 

water, 

fltrd, 

mg/L as P 

(00671)

Enterococi, 

m-E mf, 

water, 

col/100 mL 

(31649)

Fecal 

coliform, 

M-FC 

0.7μ MF 

col/100 mL 

(31625)

Boron, 

water, 

fltrd, 

μg/L 

(01046)

Iron, 

water, 

fltrd, 

μg/L

(01046)

Manganese, 

water, 

fltrd, 

μg/L

(01056)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

<0.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

<.04

9.18

2.46

5.69

.97

.4

6.26

10.7

2.68

3.11

7.32

<0.008

<.008

<.008

<.008

<.008

<.008

<.008

<.008

E.006

<.008

0.02

E.01

.03

<.02

<.02

.04

.03

E.01

<.02

.03

18

<.4

<.4

<.4

0

<.4

<.4

2

--

<.4

6

<.4

<.4

<.4

<.4

<.4

<.4

0

<.4

<.4

8.3

12

23

E4.9

7.7

E3.9

27

11

26

8.2

<6

9

<6

<6

<6

E4

<6

<6

619

<6

E0.5

20.5

5.1

8.4

25

2.9

39.2

<.6

279

E.3
Table 8 47

Table 8. Results of laboratory analysis of ground-water samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, June 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

Local 

identifier Date

1,4-Dichlorobenzene 

water, 

fltrd, 

μg/L

(34572)

1-Methylnaphthalene, 

water, 

fltrd, 

μg/L 

(62054)

2,6-Dimethylnaphthalene, 

water, 

fltrd, 

μg/L

(62055)

2-Methylnaphthalene, 

water, 

fltrd, 

μg/L 

(62056)

3-betaCoprostanol,

water, 

fltrd, 

μg/L 

(62057)

3-Methyl1Hindole, 

water, 

fltrd, 

μg/L

(62058)

3-tertButyl4-hydrozyanisole 

water, fltrd, 

μg/L

(62059)

4-Cumylphenol, 

water, 

fltrd, 

μg/L 

(62060)

4-Octylphenol, 

water, 

fltrd, 

μg/L 

(62061)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

<0.5

<.5

<.5

<.5

<.5

M

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

Local 

identifier Date

4-Nonylphenol, 

water, 

fltrd, 

μg/L

(62085)

4-tertOctylphenol, 

water, 

fltrd, 

μg/L 

(62062)

5-Methyl1H-benzotriazole, 

water, fltrd, 

μg/L

(62063)

9,10-Anthraquinone 

water, 

fltrd, 

μg/L 

(62066)

Acetophenone 

water, 

fltrd, 

μg/L

(62064)

AHTN, 

water, 

fltrd, 

μg/L 

(62065)

Anthracene, 

water, 

fltrd, 

μg/L 

(34221)

Benzo-

[a]-

pyrene, 

water, 

fltrd, 

μg/L 

(34248)

Benzophenone 

water, 

fltrd, 

μg/L

(62067)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<1

<1

<1

M

<1

<1

<1

<1

<1

<1

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

E0.2

<.5

<.5

<.5

<.5

<.5

<.5

E.1

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

M

<.5

<.5

<.5

<.5

M

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5
48 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Table 8. Results of laboratory analysis of ground-water samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, June 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

Local 

identifier Date

beta-Sitosterol, 

water, 

fltrd, 

μg/L 

(62068)

betaStigmastanol, 

water, 

fltrd, 

μg/L 

(62086)

Bisphenol A, 

water, 

fltrd, 

μg/L 

(62069)

Bisphenol Ad3 sur Sch 

2033 & 

8033, 

water, fltrd, 

pct rcv 

(99583)

Bromacil, 

water, 

fltrd, 

μg/L 

(04029)

Caffeine, 

water, 

fltrd, 

μg/L 

(50305)

Caffeine-13C 

sur Sch 

2033 & 

8033, 

water, fltrd, 

pct rcv 

(99584)

Camphor 

water, 

fltrd, 

μg/L 

(62070)

Carbaryl, 

water, 

fltrd 

0.7u GF 

μg/L 

(82680)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<1

<1

<1

<1

--

<1

<1

<1

<1

<1

59.4

80.6

25.1

78.2

24.4

67.1

28.3

30.3

32.7

74.3

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

75.5

78.6

77.2

78.6

86.3

76.5

79.3

80.7

73.3

71.9

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

Local 

identifier Date

Carbazole, 

water, 

fltrd, 

μg/L 

(62071)

Chlorpyrifos 

water, 

fltrd, 

μg/L 

(38933)

Cholesterol, 

water, 

fltrd, 

μg/L 

(62072)

Cotinine, 

water, 

fltrd, 

μg/L 

(62005)

DecaF-biphenl 

sur Sch 2033 

& 8033, 

water, fltrd, 

pct rcv 

(99585)

DEET, 

water, 

fltrd, 

μg/L 

(62082)

Diazinon, 

water, 

fltrd, 

μg/L

(39572)

Diethoxynonylphenol, 

water, 

fltrd, 

μg/L 

(62083)

Diethoxyoctylphenol, 

water, 

fltrd, 

μg/L 

(61705)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<2

<2

<2

<2

<2

<2

<2

<2

<2

<2

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

<1.00

96.3

78.6

74.5

83.9

101

88.9

78

65.4

84.3

89

M

<.5

<.5

<.5

<.5

<.5

M

M

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<5

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1
Table 8 49

Table 8. Results of laboratory analysis of ground-water samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, June 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

Local 

identifier Date

D-Limonene, 

water, 

fltrd, 

μg/L 

(62073)

Ethoxyoctylphenol,

water,

fltrd 

μg/L

(61706)

Fluoranthene 

water, 

fltrd, 

μg/L

(34377)

Fluoranthene

-d10, 

sur Sch 

20/8033 

water, fltrd, 

pct rcv 

(99586)

HHCB, 

water, 

fltrd, 

μg/L 

(62075)

Indole, 

water, 

fltrd, 

μg/L 

(62076)

Isoborneol, 

water, 

fltrd, 

μg/L 

(62077)

Isophorone 

water, 

fltrd, 

μg/L 

(34409)

Isopropylbenzene 

water, 

fltrd, 

μg/L 

(62078)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<1

<1

<1

<1

<1

<1

<1

<1

<1

<1

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

70.9

75

75.6

73.8

83.6

73.7

76.5

76.7

72.6

68.9

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

Local 

identifier Date

Isoquinoline, 

water, 

fltrd, 

μg/L

(62079)

Menthol 

water, 

fltrd, 

μg/L 

(62080)

Metalaxyl, 

water, 

fltrd, 

μg/L 

(50359)

Methyl 

salicylate, 

water, 

fltrd, 

μg/L 

(62081)

Metolachlor, 

water, 

fltrd, 

μg/L 

(39415)

Naphthalene, 

water, 

fltrd, 

μg/L 

(34443)

p-Cresol, 

water, 

fltrd, 

μg/L 

(62084)

Pentachlorophenol, 

water, 

fltrd, 

μg/L 

(34459)

Phenanthrene, 

water, 

fltrd, 

μg/L 

(34462)

CH-SP-70

CH-6880

CH-6882

CH-6879

CH-6673

CH-6878

CH-755

CH-SP-71

CH-6881

CH-6883

6/7/2005

6/2/2005

6/7/2005

6/2/2005

6/1/2005

6/2/2005

6/7/2005

6/8/2005

6/6/2005

6/8/2005

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5

<.5

<.5

<.5

<.5

M

<.5

<.5

M

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

M

<1

<1

<1

<1

<1

<1

M

<1

<1

<2

<2

<2

<2

-

<2

<2

<2

<2

<2

<0.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5

<.5
50 Effect of On-Site Wastewater Disposal on Quality of Ground Water and Base Flow

Table 8. Results of laboratory analysis of ground-water samples collected in and near the Broad Run watershed, Chester County, Pennsylvania, June 2005.—Continued (Results listed by land-use category as shown in table 3.)

[ft3/s, cubic feet per second; mi2, square miles; mm Hg, millimeters of mercury; °C, degrees Celsius; μS/cm, microsiemens per centimeter; fltrd, filtered; mg/L, 

milligrams per liter; col/100 mL, colonies per 100 milliliters; μg/L, micrograms per liter; <, less than; E, estimated value; M, measured where presence verified 

but not quantified; mL, milliliters; --, no data]

Tri- Tri- Tetra- Tri- Tri- Prome- butyl Triclo- phenyl Phenol, Pyrene, chloro- bromo- ethyl ton, phos- san, phos- water, water, ethene, methane citrate Local water, phate, water, phate, Date fltrd, fltrd, water, water, water, identifier fltrd, water, fltrd, water, 

μg/L μg/L fltrd, fltrd, fltrd, 

μg/L fltrd, μg/L fltrd, (34466) (34470) μg/L μg/L μg/L (04037) μg/L (62090) μg/L (34476) (34288) (62091) (62089) (62092)

CH-SP-70 6/7/2005 E0.2 <0.5 <0.5 M <0.5 <0.5 <1 <0.5 <0.5

CH-6880 6/2/2005 E.2 <.5 <.5 <.5 <.5 <.5 <1 <.5 <.5

CH-6882 6/7/2005 E.3 <.5 <.5 <.5 <.5 <.5 <1 <.5 <.5

CH-6879 6/2/2005 E.2 <.5 <.5 <.5 <.5 <.5 <1 <.5 <.5

CH-6673 6/1/2005 .6 <.5 <.5 <.5 <.5 <.5 <1 <.5 <.5

CH-6878 6/2/2005 E.4 <.5 <.5 M <.5 <.5 <1 <.5 <.5

CH-755 6/7/2005 E.3 <.5 <.5 <.5 <.5 <.5 <1 <.5 <.5

CH-SP-71 6/8/2005 E.4 <.5 <.5 <.5 <.5 <.5 <1 <.5 <.5

CH-6881 6/6/2005 <.5 <.5 <.5 <.5 <.5 <.5 <1 <.5 <.5

CH-6883 6/8/2005 E.1 <.5 <.5 <.5 <.5 <.5 <1 <.5 <.5

Tris (2- Tris (2- Tris (di Sample 

butoxy- chloro- chloro- volume, Sampler Sampling ethyl) ethyl) i-Pr) wastewater Local type, condition, Date phosphate, phosphate, phosphate, method identifier code code water, fltrd, fltrd, water, fltrd, water, fltrd (84164) (72006) μg/L μg/L μg/L mL 

(62093) (62087) (62088) (99587)

CH-SP-70 6/7/2005 E0.2 <0.5 <0.5 832 4080 .10

CH-6880 6/2/2005 <.5 <.5 <.5 897 4040 .10

CH-6882 6/7/2005 <.5 <.5 <.5 873 4090 .10

CH-6879 6/2/2005 E.3 <.5 <.5 905 4040 .10

CH-6673 6/1/2005 <.5 <.5 <.5 864 4040 .10

CH-6878 6/2/2005 <.5 <.5 <.5 891 4040 .10

CH-755 6/7/2005 <.5 <.5 M 847 4040 .10

CH-SP-71 6/8/2005 <.5 <.5 <.5 831 4080 .10

CH-6881 6/6/2005 <.5 M <.5 837 4040 .10

CH-6883 6/8/2005 <.5 <.5 <.5 827 4040 .01