In cooperation with the 

Maryland Department of the Environment 

Occurrence and Distribution of 

Microbiological Contamination and 

Enteric Viruses in Shallow Ground Water in 

Baltimore and Harford Counties, Maryland 

Water-Resources Investigations Report 01-4216 

U.S. Department of the Interior 

U.S. Geological Survey 
The contents of this report have been approved for public release and unlimited distribution by the U.S. Army--

clearance number 3793-A-6

U.S. Department of the Interior 

U.S. Geological Survey 

Occurrence and Distribution of 

Microbiological Contamination and 

Enteric Viruses in Shallow Ground Water in 

Baltimore and Harford Counties, Maryland 

By William S.L. Banks (U.S. Geological Survey) and


David A. Battigelli


(Wisconsin State Laboratory of Hygiene)


Water-Resources Investigations Report 01-4216


In cooperation with the 

Maryland Department of the Environment 

Baltimore, Maryland 

2002 
U.S. Department of the Interior 

GALE A. NORTON, Secretary 

U.S. Geological Survey 

Charles G. Groat, Director 

The use of trade, product, or firm names in this report is for 

descriptive purposes only and does not imply endorsement 

by the U.S. Government. 

For additional information contact: 

District Chief 

U.S. Geological Survey 

8987 Yellow Brick Road 

Baltimore, MD 21237 

Copies may be purchased from: 

U.S. Geological Survey 

Branch of Information Services 

Box 25286 

Denver, CO 80225-0286 
CONTENTS

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

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

Background....................................................................................................................................................................2

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

Location and description of study area..........................................................................................................................3

Hydrogeologic setting...........................................................................................................................................3

Ground-water use..................................................................................................................................................4

Acknowledgments.........................................................................................................................................................4

Study design and methods......................................................................................................................................................4

Target population ...........................................................................................................................................................5

Site selection..................................................................................................................................................................5

Sample collection ..........................................................................................................................................................5

Sample analysis.....................................................................................................................................................8

Quality assurance and quality control...................................................................................................................9

Occurrence and distribution of viral contamination...............................................................................................................9

Summary and conclusions....................................................................................................................................................13

References cited ...................................................................................................................................................................13

Appendix: Microbiological and water-quality data for 91 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through November 2000 ..............................................16

Figures

1-3. Maps showing: 

1. Location of study area, Baltimore and Harford Counties, Maryland...................................................................3

2. Location of sampled public water-supply wells in Baltimore and Harford Counties, Maryland ........................6

3. Location of detected microbiological constituents and total oxidized nitrogen detection

above 10.0 milligrams per liter in sampled public water-supply wells in Baltimore and

Harford Counties, Maryland...........................................................................................................................10

Tables

1. Microbiological, nutrient, and field constituents sampled in Baltimore and Harford Counties, Maryland.........7

2. Kendall's Tau correlation coefficient for total coliform concentrations and continuous

explanatory variables......................................................................................................................................12

iii 
_____________________________________________________________________________________________________________________________________ 

_____________________________________________________________________________________________________________________________________ 

_____________________________________________________________________________________________________________________________________ 

Conversion Factors and Vertical Datum 

Multiply By To obtain 

inch (in.) 2.54 centimeter 

inch per year (in/yr) 2.54 centimeter per year 

million gallons per day (Mgal/d) 3,785 cubic meter per day 

gallon per day (gal/d) 3.785 liter per day 

gallon (gal) 3.785 liter 

mile (mi) 1.609 kilometer 

square mile (mi

2

) 2.590 square kilometer 

acre 4,047 square meter 

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

°

C = ( °F - 32) / 1.8 

Vertical datum: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929—a geodetic datum 

derived from a general adjustment of the first-order level nets of the United States and Canada, formerly called Sea Level 

Datum of 1929. 

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

micrograms per liter (μg/L), or molarity. 

Concentrations of microbiological constituents in water are given either in plaque-forming units (pfu) or 

colony-forming units (cfu) per unit volume. 

iv 
Occurrence and Distribution of Microbiological Contamination 

and Enteric Viruses in Shallow Ground Water in 

Baltimore and Harford Counties, Maryland 

By William S.L. Banks and David A. Battigelli 

Abstract 

The U.S. Geological Survey, in cooperation 

with the Maryland Department of the Environment 

and the Wisconsin State Laboratory of Hygiene, 

conducted a study to characterize the occurrence 

and distribution of viral contamination in small 

(withdrawing less than 10,000 gallons per day) 

public water-supply wells screened in the shallow 

aquifer in the Piedmont Physiographic Province in 

Baltimore and Harford Counties, Maryland. Two 

hundred sixty-three small public water-supply 

wells were in operation in these counties during 

the spring of 2000. Ninety-one of these sites were 

selected for sampling using a methodology that 

distributed the samples evenly over the population 

and the spatial extent of the study area. Each site, 

and its potential susceptibility to microbiological 

contamination, was evaluated with regard to hole 

depth, casing interval, and open interval. Each site 

was evaluated using characteristics such as on-site 

geology and on-site land use. 

Samples were collected by pumping between 

200 and 400 gallons of untreated well water 

through an electropositive cartridge filter. Water 

concentrates were subjected to cell-culture assay 

for the detection of culturable viruses and reversetranscription polymerase chain reaction/gene 

probe assays to detect viral ribonucleic acid; grab 

samples were analyzed for somatic and malespecific coliphages, Bacteroides fragilis, 

Clostridium perfringens, enterococci, Escherichia 

coli, total coliforms, total oxidized nitrogen, 

nitrite, organic nitrogen, total phosphate, orthophosphate, calcium, magnesium, sodium, potassium, chloride, sulfate, iron, acid-neutralizing 

capacity, pH, specific conductance, temperature, 

and dissolved oxygen. 

One sample tested positive for the presence of 

the ribonucleic acid of rotavirus through polymerase chain-reaction analysis. Twenty-nine percent of the samples (26 of 90) had bacterial contamination. About 7 percent of the samples (6 of 

90) were contaminated with either male-specific 

coliphage, somatic coliphage, or bacteriophages of 

Bacteroides fragilis. About 3 percent of the samples (3 of 87) had oxidized nitrogen concentrations that exceeded the U.S. Environmental 

Protection Agency’s Maximum Contaminant 

Level of 10.0 milligrams per liter. A statistical 

analysis showed that no significant relation exists 

between the presence of bacteria or coliphage and 

all variables, except the mean temperature of the 

water sample as measured in the field. Additionally, the concentration of total coliform bacteria had 

a statistically significant, moderately strong correlation with the concentration of sulfate and 

sample pH as measured at the U.S. Geological 

Survey National Water-Quality Laboratory in 

Denver, Colorado. 

Introduction 

In response to the 1996 Amendments to the Safe Drinking Water Act, the U.S. Environmental Protection Agency 

(USEPA) is developing the Ground-Water Rule (GWR) to 

protect users of public ground-water supplies from viral 

contamination (U.S. Environmental Protection Agency, 

2001a). Because total coliform bacteria often is used as an 

indicator of the possibility or likely presence of pathogenic 

contamination from microbial pathogens, many groundwater suppliers use the absence of coliform as justification 

for not disinfecting source water. In addition, because of the 

high cost and complex analytical methods involved, direct 

Abstract 1 
monitoring for viruses seldom is done in public-water 

supplies (U.S. Environmental Protection Agency, 1986). 

In 1998, the U.S. Geological Survey (USGS), in cooperation with the Maryland Department of the Environment 

(MDE) and the Wisconsin State Laboratory of Hygiene 

(WSLH), began a study to characterize the occurrence and 

distribution of enteric viruses in small (less than 10,000 gallons per day, or gal/d) public water-supply wells in the 

aquifers of the Piedmont Physiographic Province of 

Baltimore and Harford Counties, Maryland. Because of 

difficulties associated with direct monitoring for viral contamination (such as cost and turn-around time), it has not 

been feasible to routinely document the presence or absence 

of viruses in public-water supplies. Therefore, studies are 

needed to characterize the occurrence and distribution of 

viral contamination in ground water used for drinking water 

throughout the United States. 

Background 

Viruses are among the smallest of the disease-causing 

microorganisms found in the aquatic environment. In 1996, 

the U.S. Congress amended the Safe Drinking Water Act to 

require that all states develop methods for assessing the 

vulnerability of drinking-water supplies to various regulated 

contaminants. In addition, states were granted the authority 

to include other contaminants that might present a threat to 

public health. For this reason, Maryland included enteric 

viruses as a part of its assessment criteria. More than 120 

different types of potentially harmful enteric viruses are 

excreted in human feces, and are widely distributed in type 

and number in domestic sewage, agricultural wastes, and 

septic drainage systems (Gerba, 1988). Many of these 

viruses are stable in natural waters and have long survival 

times with half-lives ranging from weeks to months. Because they may cause disease even when just a few virus 

particles are ingested, low levels of environmental contamination may affect water consumers. From 1971 to 

1979, approximately 57,974 people in the United States were 

affected by outbreaks of waterborne pathogens (Craun, 

1986). Outbreaks of waterborne disease attributed to enteric 

viruses are poorly documented, even though viruses are 

commonplace in natural waters contaminated with human 

feces. Illnesses in humans caused by waterborne viruses 

range from severe infections such as myocarditis, hepatitis, 

diabetes, and paralysis to relatively mild conditions such as 

self-limiting gastroenteritis. It has not been possible to 

identify the etiologic agent or agents responsible for community illness in approximately half of the reported waterborne outbreaks because the isolation and identification of 

the causative agent was either unsuccessful or not attempted 

(Craun and McCabe, 1973; Craun, 1986; Sobsey, 1989). 

Additional analyses indicate that caliciviruses such as the 

Norwalk virus and other enteric viruses may be responsible 

for as much as 60 percent of the reported waterborne outbreaks of gastroenteritis since the clinical features of the 

cases in many of these epidemics are consistent with viral 

infections, and bacterial pathogens were ruled out as disease 

agents (Keswick and Gerba, 1980; Kaplan and others, 1982; 

U.S. Environmental Protection Agency, 1988; Herwaldt and 

others, 1992). Despite the inherent difficulties associated 

with the identification of viruses in water, disease outbreaks 

have been attributed to specific episodes of viral contamination in ground water (Craun and others, 1976; Hejkal and 

others, 1982; Herwaldt and others, 1992; Divizia and others, 

1993; Beller and others, 1997). Because approximately half 

of the reported outbreaks of waterborne disease in the United 

States from 1970 through 1990 had undefined etiologies, 

establishing causality between specific viral agents and 

illness caused by contaminated water supplies remains 

difficult. Nevertheless, enteric viruses such as the Norwalk 

and Norwalk-like viruses have been established as the major 

cause of viral gastroenteritis among adults world-wide 

(Beller and others, 1997). 

The USEPA has identified numerous potential sources of 

viral contamination in ground water, including wastewater in 

commercial and industrial settings, septic systems in residential and municipal settings, and condensed animal-feeding operations in rural or agricultural areas. Currently 

(summer 2001), the Total Coliform Rule is used to screen for 

fecal contaminants, and is the only Federal drinking-water 

regulation in effect for determining the presence of microbes 

in public ground-water systems not directly under the 

influence of surface water. 

Other nonpathogenic microorganisms also have been 

suggested as viral indicators. Coliphages are bacterial 

viruses that infect the coliform bacterial group. Some coliphages are superficially similar to the enteric viruses in that 

they share symmetrical structures, morphologies, and sizes, 

and have similar half-lives in natural waters. Some coliphages, particularly those that infect “male” strains of 

Escherichia coli (E. coli), or “male-specific” coliphages, can 

be found in human feces and have been identified in large 

numbers in human wastewater (Havelaar, 1986). Malespecific coliphages and other bacteriophages have been 

proposed as viral indicator microorganisms because (1) outbreaks of viral etiology have been documented in waters that 

met coliform criteria for drinking purposes (Kukkula and 

others, 1999); (2) viruses may be considerably more resilient 

in the environment than coliforms; and (3) the infectious 

dose of many viral diseases is considerably lower than that 

observed for enteric bacterial disease (Hejkal and others, 

1982). 

Other microorganisms under consideration as viral 

indicators include fecal streptococci and enterococci, 

certain anaerobic bacteria such as Clostridium perfringens 

(C. perfringens), Bacteroides fragilis (B. fragilis) and the 

Bifidobacteria. Low recovery rates have been reported for 

B. fragilis and Bifidobacteria; however, both of these 

bacteria are relatively sensitive to inactivation by chlorine 

and their reported presence in water has sometimes been 

inconsistent, rendering them equivocal as an indicator 

organism for human enteric viruses (Sartory, 1980; Allsop 

and Stickler, 1985). 

2 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Purpose and Scope 

The purpose of this report is to describe microbiological 

occurrence in ground water in small public water-supply 

systems and possible factors affecting well vulnerability to 

microbiological contamination in the aquifers of the 

Piedmont Physiographic Province in Baltimore and Harford 

Counties, Maryland. The report relates the occurrence of 

microorganisms to well information, on-site geology, on-site 

land use, and selected chemical constituents. 

One hundred and one samples were collected from 

April 10, 2000 to November 13, 2000. Ninety of these samples were selected based on a random, spatially distributed 

sample population. Ten replicate samples were collected to 

assess variability. One additional, randomly selected site in 

Baltimore County also was sampled. 

Location and Description of Study Area 

Baltimore and Harford Counties compose 1,039 mi

2 

(square miles) of north-central Maryland. The area is 

bordered to the north by York and Lancaster Counties, 

Pennsylvania, to the west by Carroll and Howard Counties, 

Maryland, and to the east and south by Cecil County, the 

Chesapeake Bay, and Anne Arundel County, Maryland, (fig. 

1). The study area includes parts of the two counties where 

public water-supply wells have been drilled into consolidated crystalline rock. This area generally is west of the 

Fall Line in both counties. The Fall Line (fig. 1) is a zone 

trending northeast to southwest that separates the unconsolidated sediments of the Atlantic Coastal Plain Physiographic Province from the igneous and metamorphic rocks 

of the Piedmont Physiographic Province. The study area is 

characterized by rolling hills and moderately to deeply incised valleys, with altitudes ranging from sea level to more 

than 900 ft (feet) above sea level. 

The northern part of the study area is mostly rural, while 

areas to the south and east tend to be more urban. The total 

population of both counties in the year 2000 was 972,882. 

Towson, the county seat of Baltimore County, is located in 

the central part of Baltimore County and has a population of 

51,793. The town of Bel Air is the Harford County seat. 

The town and its suburbs have a combined population of 

75,589 (U.S. Bureau of the Census, 2001).

 The climate of the study area is temperate. Average 

temperatures range from about 35 °

F (degrees Fahrenheit) in 

the winter to about 70 °

F in the summer. Rain and snowfall 

vary seasonally, and average about 41 in/yr (inches per year) 

(National Oceanic and Atmospheric Administration, 1977). 

Hydrogeologic Setting Ground water in the study area 

can be found under water-table or confined conditions. As 

in the Coastal Plain Physiographic Province, ground water 

fluctuates seasonally in response to variations in precipiIntroduction 3 
tation, evapotranspiration, and local ground-water withdrawals. Ground water in the Piedmont Province is found 

under water-table conditions in the saprolite overburden and 

in the joints and fractures of the crystalline rock. The 

saprolite layer is formed by the chemical weathering of 

native rock material. The thickness of the saprolite layer 

and its capability to transmit water are dependent on the 

lithology and structure of the parent rock. As the rock is 

weathered, many features (such as joints and fractures) are 

preserved in the saprolite. The joints and fractures found in 

crystalline rock are the result of stresses in the Earth’s crust 

and occur with greater frequency and more interconnections 

closer to the Earth’s surface. In addition, these structures 

tend to be more localized in topographic lows than in 

topographic highs. Nutter and Otton (1969) noted that this 

localization is partly because valleys in the Piedmont 

Province develop along zones of fracture. 

The hydraulic properties of the Maryland Piedmont 

tend to reflect both unconsolidated material and crystalline 

rock. The porosity of 34 saprolite samples from Maryland 

and Georgia averaged 46.8 percent (Nutter and Otton, 1969). 

Where saprolite is present, its porosity varies with depth, 

reaching a maximum at about 30 to 40 ft below land surface. 

At greater depths, porosity decreases as saprolite grades to 

unweathered rock (Nutter and Otton, 1969). The porosity of 

unweathered rock is much lower on average than that of the 

saprolite, ranging from about 0.01 to 2 percent (Heath , 

1984). The hydraulic conductivity of saprolite also 

decreases with depth, but tends to increase near the contact 

between the saprolite and the unweathered rock. Well 

drillers often report encountering sand and gravel in this 

zone and many wells are finished to take advantage of this 

phenomenon. The most productive wells tend to be located 

in areas where multiple fractures or joints occur and where 

the overburden has sufficient hydraulic head and permeability. Because permeability decreases with depth in 

crystalline rock, well yields also tend to decrease with depth. 

The lower boundary of the surficial aquifer is defined as 

the base of the zone where interconnected fractures cease 

to be present (Davis and DeWiest, 1966; Heath, 1984; 

Bolton, 1998). Further information on the hydrogeology 

of the Maryland Piedmont can be found in Dingman and 

Ferguson (1956), Otton and others (1964), and Bolton 

(1998). 

Ground-Water Use Shallow ground water in northern 

Baltimore and northwestern Harford Counties is the major 

water-supply source for industry, agriculture, and domestic 

self-supplied drinking water. Approximately 10.63 Mgal/d 

(million gallons per day) of ground water is pumped from 

the water-table aquifer in the Piedmont Province of 

Baltimore and Harford Counties (Judith Wheeler, U.S. 

Geological Survey, oral commun., 2001). The majority of 

shallow ground water used in the two-county area is for 

domestic self-supply (8.2 Mgal/d) and commercial use 

(1.1 Mgal/d). Public water supply accounts for about 

0.37 Mgal/d. Agricultural activities account for about 

0.7 Mgal/d, and industry and mining use approximately 

0.33 Mgal/d. Well depths in the study area range from tens 

of feet in settings where fractures and joints are closely 

spaced and ground-water yields are substantial, to well over 

300 ft in areas where fractures and joints are farther apart. 

Nutter (1977) noted that well yields generally do not 

improve with depth and suggested that most, if not all, 

water-bearing fractures are within 300 ft of the land surface. 

The interconnected nature of joints and fractures in the 

Piedmont Province often obscures the source and direction 

of ground-water flow. This makes identification of contaminant sources difficult. Although no direct correlation 

has been established in the study area between the consumption of fecally contaminated water from a public watersupply system and waterborne illnesses, the relatively shallow depth to the water table and the common use of septic 

systems as a means of sewage disposal increase the potential 

for enteric viruses and other microbiological contamination 

to be transported to the water table. 

Acknowledgments 

The authors thank John Grace and Lyn Poorman of the 

Maryland Department of the Environment for logistical 

support in this study. Travis Sterner and Andrea Korsak, 

also of the Maryland Department of the Environment, 

assisted in providing information on water system owners 

and operators. Funding for this study was provided through 

a cooperative effort between the Maryland Department of 

the Environment and the U.S. Geological Survey. 

Study Design and Methods 

Viruses are not capable of reproduction outside of a suitable host or host cell; therefore, the occurrence of viruses in 

a water supply is directly related to the supply’s proximity to 

fecal contamination. Various studies have indicated that 

pathogen occurrence in ground-water supplies and pathogen 

transport in porous media may be affected by hydrogeology, 

soil type, and well-construction characteristics (Bales and 

others, 1995; DeBorde and others, 1998; Abbaszadegan and 

others, 1998; Gerba, 1999). Numerous studies on the traveltimes and inactivation rates of viruses in ground water have 

been conducted, and the results do not compare well. In 

experiments with live attenuated viruses, Noonan and 

McNabb (1979) documented that viruses could travel more 

than 2,953 ft, whereas Vaughn and Landry (1977) showed a 

maximum travel distance of 150 ft. Wellings and others 

(1975) suggested that virus survival time in ground water 

may be as little as 28 days, whereas Gerba and others (1975) 

suggested that at very low temperatures (below 4 °

C, or 

degrees Celsius), viruses can survive in ground water for 

months to years. In laboratory studies, Gerba (1999) related 

virus survival to soil moisture and depth to the water table 

stating that although many viruses are resistant to inactivation by desiccation, viruses that must pass through an unsaturated soil zone may be permanently adsorbed to soil 

particles, thus rendering them either inactive or unavailable 

for transport. 

4 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
One hundred forty-nine small public water supplies were 

available for sampling in Baltimore County, but only 114 

sites were available in Harford County. To ensure an approximately equal number of samples in each county, sites 

were chosen based on a modification of Madow’s (1949) 

method for constructing a spatially structured list frame. 

Samples were selected through a hierarchical randomization 

process that increased the probability of well selection in 

Harford County. After all sampling sites had been chosen, a 

geographic information system (GIS) was used to identify 

potential mappable characteristics that may be related to 

sources of fecal contamination. Land-use data (Maryland 

Department of the Environment, 1994) was used as a surrogate for potential sources of enteric viruses. Data on well 

depth, casing depth, open interval, and on-site geology 

(Cleaves, 1968) were used to evaluate the small public 

water-supply well’s susceptibility to contamination. 

Target Population 

For this study, only public water-supply systems that rely 

on ground water were evaluated. A public ground-water 

supply system in the State of Maryland includes any system 

that provides piped water for human consumption and has 

at least 15 service connections, or regularly serves at least 

25 individuals daily at least 60 days out of the year (State of 

Maryland, [n.d.]). Small public water supplies in Baltimore 

and Harford Counties can be classified this way and provide 

less than 10,000 gal/d for public use, draw water from shallow wells (typically less than 300 ft deep), and are located in 

rural and low-density suburban areas. Currently (2001), 

many small public water supplies do not have the regulatory 

need or the financial resources necessary to disinfect their 

finished water. As a result, they are among the most susceptible to contamination from viral pathogens. 

Small public supplies are divided into two categories, 

community water systems and non-community water systems. Community systems serve at least 15 connections 

used by year-round residents, or serve at least 25 residents 

throughout the year. Examples of community systems 

include mobile home parks and small apartment buildings. 

Non-community systems are further divided into transient 

and non-transient systems. A non-transient, non-community 

system serves at least 25 of the same people for more than 

6 months per year. Schools and day-care facilities are 

typical examples of non-transient non-community systems. 

A transient non-community system serves less than 25 of the 

same people for more than 6 months per year. Examples 

include offices, churches, and markets (State of Maryland, 

[n.d.]). 

Site Selection 

Sites were selected from the 263 small public watersupply systems that were active in Baltimore and Harford 

Counties in the spring of 2000. Some sites were east of the 

Fall Line, but were finished in the crystalline rock below a 

veneer of Coastal Plain sediment, and were therefore included in the study. Site selection was based on a modification of Madow’s (1949) method that used an inclusion 

probability proportional to an arbitrary weight for each 

county. The intended sample size was 90, with an approximately equal number of sites from each county. The proportion of the target population was computed based on 149 

sites in Baltimore County and 114 sites in Harford County. 

This assigned a weight of 1.0 to Baltimore County and a 

weight of 1.31 to Harford County (149/114 = 1.31). The 

total weight was 298.34 [(1.31*114) + 149]. To compute 

the inclusion probability for any given site, the weight of 

each site was multiplied by the sample size. The product 

was then divided by the total weight. Thus, the inclusion 

probabilities for Baltimore and Harford Counties were 0.334 

and 0.438, respectively. 

The sample selection procedure was used to increase the 

probability of selecting a near-equal distribution of sites 

between the two counties. The final result yielded 45 sites 

for both Baltimore and Harford Counties, after accounting 

for replacements. Sample selection began by placing all 

263 sites in random order. Each site was assigned a normalized weight equivalent to the total number of sites multiplied 

by the appropriate county weight. A cumulative sum for the 

normalized weight was kept for each site. A random starting point between 0 and 2.99 (total weight divided by sample 

size) was selected and a systematic sampling (Cochran, 

1977) was performed. This method was used to make three 

separate selections without replacements of 100 sites each, 

and provided 2 alternate sites in case the primary site was 

found unsuitable for sampling. 

Site canvassing began in March 2000. The owner or 

operator of each public water-supply system was contacted, 

and given a general description of the purpose of the study 

and asked to voluntarily participate. If the owner or 

operator declined participation, an alternate site was contacted. In 12 cases, the alternate site was the same as the 

primary site, so a second alternate site was contacted. Approximately 20 percent of the owners or operators contacted 

declined to participate in the study. Reasons for declining 

included a fear of increased resource regulation to a general 

distrust of Government. Selected sampling sites are shown 

in figure 2. 

Sample Collection 

One hundred and one samples were collected from 

April 10, 2000 to November 13, 2000. Ninety of these 

sample sites were selected based on the procedure described 

in the previous section. An additional site in Baltimore 

County, selected randomly, also was sampled. Ten replicate 

samples were collected to monitor the reproducibility of 

laboratory results. All samples were analyzed for a suite of 

enteric constituents, nutrients, and field parameters (table 1). 

Samples for microbiological analyses were submitted to the 

WSLH in Madison, Wisconsin. Nutrient samples were 

analyzed at the USGS National Water-Quality Laboratory 

(NWQL) in Denver, Colorado. Specific conductance, acidneutralizing capacity, dissolved oxygen, water temperature, 

and pH were measured in the field by employees of the 

USGS Baltimore, Maryland office using methods described 

in Wilde and Radtke (1998). 

Study Design and Methods 5 
6 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Table 1. Microbiological, nutrient, and field constituents sampled in Baltimore and 

 Harford Counties, Maryland

 [mL, milliliter; mg/L, milligrams per liter; °C, degrees Celsius; WSLH, Wisconsin State Laboratory of Hygiene;

 USGS NWQL, U.S. Geological Survey National Water-Quality Laboratory; USEPA, U.S. Environmental Protection Agency; 

 MPN, most probable number] 

Constituent Method Units Analytical laboratory Reference 

Enteric virus cell-culture presence / absence WSLH, Madison Wi. USEPA, 1996 

Enteric virus reverse- Electrophoresis WSLH, Madison Wi. Abbaszadegan and 

transcriptase, (presumptive) and others, 1999 

polymerase chain Membrane 

reaction (RT-PCR) Hybridization 

(confirmatory) 

Somatic coliphage quantitative, 1 MDS plaque-forming units WSLH, Madison, Wi. Sinton and others, 

filter / elution and per 500 mL 1996 

enrichment 

Male-specific coliphage quantitative, 1 MDS plaque-forming units WSLH, Madison Wi. Sinton and others, 

filter / elution and per 500 mL 1996 

enrichment 

Bacteroides fragilis quantitative, 1 MDS plaque-forming units WSLH, Madison Wi. USEPA, 1996 

phages filter / elution and per 500 mL 

enrichment 

Total coliforms Colilert colonies per 100 mL WSLH, Madison, Wi. USEPA, 1996 

Clostridium perfringens quantitative, colonies per 200 mL WSLH, Madison, Wi. Bisson and Cabelli, 

membrane filtration 1979 

Enterococci Enterolert MPN / 100 mL WSLH, Madison, Wi. USEPA, 1996 

Escherichia coli Colilert colonies per 100 mL WSLH, Madison, Wi. USEPA, 1996 

Total organic carbon infrared analyzer mg/L USGS NWQL, Wershaw and others, 

Denver, Co. 1987 

Nitrogen (nitrate, nitrite, colorimetry mg/L USGS NWQL, Fishman and 

ammonium, and organic Denver, Co. Friedman, 1989 

nitrogen) 

Phosphorus colorimetry mg/L USGS NWQL, Fishman and 

(total, ortho) Denver, Co. Friedman, 1989 

pH electrode pH units USGS, Field Wilde and Radtke, 

1998 

Specific conductance contact-type microsiemens per USGS NWQL, Wilde and Radtke, 

electrode centimeter at 25 °

C Denver, Co. 1998 

Acid-neutralizing titration mg/L as bicarbonate USGS, Field Wilde and Radtke, 

capacity 1998 

Temperature thermistor °

C USGS, Field Wilde and Radtke, 

1998 

Dissolved oxygen idometric mg/L USGS, Field Wilde and Radtke, 

1998 

Study Design and Methods 7 
Samples for microbiological analysis were collected 

based on protocols established under the Information 

Collection Rule (U.S. Environmental Protection Agency, 

1996). All equipment and sampling containers used to 

collect microbiological samples were sanitized and sealed at 

WSLH. Prior to sampling, public water-supply system 

wells were purged of standing water. Purging was done in 

accordance with protocols for measuring pH, water temperature, and specific conductance established for the USGS 

National Water-Quality Assessment Program and described 

in Koterba and others (1995). USGS personnel collected 

samples by passing between 200 and 400 gal (gallons) 

through a Virosorb 1 MDS A positively charged cartridge 

filter. Samples were collected from the hose connection 

closest to the well head. Systems using chlorination, 

filtration, or water-softening equipment were evaluated and 

samples from the well were collected before treatment. 

Sites with treatment systems that could not be bypassed were 

not sampled. Samples with a pH of greater than 8.0 were 

neutralized by continuously injecting a 1.0 Normal solution 

of hydrochloric acid to the sample stream through a one-way 

vacuum valve prior to filtration. Samples were shipped on 

ice by overnight courier to NWQL in Denver, Colorado, and 

WSLH in Madison, Wisconsin. Sample holding times were 

within USEPA standards for routine monitoring of ground 

water (U.S. Environmental Protection Agency, 1996). 

Holding times for two samples (samples BA Bd 239 and 

HA Cc 196) exceeded 24 hours. The USEPA recommends 

that viral samples not be held more than 48 hours (U.S. 

Environmental Protection Agency, 1996). The WSLH 

requires that sample temperatures be below 19 °

C upon 

arrival at the laboratory. Both samples arrived within the 

criteria outlined above, and when analyzed, did not contain 

microbiological contamination. 

Sample Analysis Viral analysis was performed at 

WSLH by cell culture and a modification to the reversetranscript-ase, polymerase chain reaction (RT-PCR) method 

developed by Abbaszadegan and others (1999). Viruses 

were eluted from the 1 MDS filter using alkaline beef 

extract/glycine solution. The extract was concentrated and 

eluted again with a 1.5 molar sodium phosphate solution. 

Gene probe assays were conducted by subjecting a portion of 

the water concentrate (650 μL, or microliters) to 

guanidinium isothio-cyanate-phenol/chloroform extraction 

under acid conditions to extract viral ribonucleic acid 

(RNA). Samples then were purified through molecular 

exclusion drip columns com-posed of sephadex G-100 and 

RNA was ethanol-precipitat-ed in a vacuum evaporator. 

Viral RNA then was reverse-transcribed and subjected to 

PCR in a thermal cycler B according to a thermal profile 

specific to each virus group. For hepatitis A viruses, 

enteroviruses, and rotaviruses, the thermal profile included a 

4-minute pre-incubation at 95 °

C to denature viral RNA, 

A. Cuno Corporation, Meriden, Connecticut. B. Stratagene, La Jolla, California. C. Bio-Rad Corporation, Hercules, California. D. Hyclone Laboratories, Logan, Utah. 

followed by 35 cycles of de-naturation (75 seconds), 

annealing (75 seconds), and polymerization (75 seconds) at 

95 °

C, 55 °C, and 72 °C, respectively. For the caliciviruses, 

following the initial 

95 °

C denaturation step, the thermal profile included 40 

cycles of 94 °

C (75 seconds), 50 °C (75 seconds), and 60 °C 

(120 seconds). Following PCR, all virus samples were 

incubated at 72 °

C for 10 minutes to extend incompletely 

polymerized deoxyribonucleic acid (DNA) strands. Following nucleic acid amplification, samples were subjected to 

agarose gel electrophoresis to identify presumptive viralpositive samples. DNA then was transferred to nylon 

membranes under vacuum C , membranes were crosslinked 

by ultraviolet irradiation and then were probed using 

3’-digoxigenin end-labeled oligoprimers specific to each 

virus group to confirm identity. Only the samples that were 

confirmed by oligoprobing were considered positive for viral 

nucleic acid. 

A portion of the water concentrate also was reserved for 

inoculation into cell cultures in order to determine if culturable viruses were present. An inoculum equivalent to 

100 liters of the original sample was divided into 10 aliquots 

and introduced onto confluent monolayers of Buffalo green 

monkey kidney (BGMK) cells in 25-cm2

 (square centimeter) tissue culture flasks according to the Information 

Collection Rule (ICR) method (U.S. Environmental Protection Agency, 1996). Following a 60-minute adsorption 

period, flasks were supplemented with maintenance medium 

containing 2 percent fetal calf serum D and flasks were 

incubated for 2 weeks at 37 °

C. Flasks were examined on 

days 1, 2, 3, 7, and 14 following infection to identify if viral 

cytopathic effects (CPE) were evident. Samples negative 

for viral CPE were reinoculated onto a second series of 

flasks that were examined using the same method for 

2 weeks. Samples confirmed as positive for culturable 

viruses were serotyped to identify viral species. 

Samples for total coliforms, E. coli, and enterococci were 

collected in two 100-mL (milliliter) sterile containers prior 

to the installation of the virus filtration apparatus at the 

sampling sites. The Enterolert Quanti-tray system was used 

to enumerate enterococci. E. coli and total coliforms were 

analyzed using the Colilert Quanti-tray system. Both kits 

are approved for use by the USEPA (U.S. Environmental 

Protection Agency, 1996). The kits commonly are used and 

are available from Idexx Laboratories in Westbrook, Maine. 

Analysis for C. perfringens was performed according to 

methods previously described (U.S. Environmental 

Protection Agency, 1996). These methods require that a 

200-mL sample be anaerobically incubated after membranefiltration onto mCP medium. 

Samples were analyzed for male-specific and somatic 

coliphage using a two-step enrichment method that was 

recently incorporated into the USEPA draft method for 

8 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
coliphage detection (U.S. Environmental Protection Agency, 

2001b). For this study, 500 mL grab samples were 

supplemented with magnesium chloride and bacterial 

nutrients and were then inoculated with 2.5 mL log-phase 

host bacteria specific for each bacteriophage group (somatic 

or male-specific). Following overnight enrichment at 35 °

C, 

10 μL droplets from the enriched cultures were spotted onto 

nutrient agar plates containing confluent lawns of host 

bacteria. Plates were examined for zones of lysis following 

a second incubation at 36 °

C. Samples with clear zones 

within the bacterial lawn were considered positive for 

bacteriophages. B. fragilis, a class of bacteriophage that 

infect anaerobic bacteria, were extracted from a 100-mL 

sample and plated under anaerobic conditions using a B. 

fragilis HSP40 host cell. Inoculated plates were incubated 

for 24 hours. 

Quality Assurance and Quality Control Qualityassurance and quality-control (QA/QC) samples were 

collected to ensure that equipment cleaning and sterilization 

techniques were adequate, to assess possible field contamination of samples, and to determine sampling and 

analytical variability. Replicate samples are used to assess 

the variability introduced by sampling or analytical procedures. Ten replicate samples were collected for this study. 

Because none of the environmental samples or their 

associated replicates were reported to be contaminated with 

viral or coliphage contamination, no measure of variability 

can be quantified for these constituents. Two samples, 

BA Fb 82 and HA Dc 122, were contaminated with total 

coliforms, however. The environmental sample for site 

BA Fb 82 had 28 cfu/100 mL (colony-forming units per 

100 mL). Its replicate sample had 27 cfu/100 mL. Sample 

HA Dc 122 had 3 cfu/100 mL and its replicate had 

2 cfu/100 mL. These values are not sufficient to quantify 

variability, but they do indicate qualitatively that sampling 

and analytical methods are capable of detecting total coliform bacteria at levels above the method reporting level. 

Two samples collected for a companion study using the same 

sample-collection and analytical procedures served as 

negative controls (Klohe and Feehley, 2001). The samples 

were collected from public water-supply wells with properties not vulnerable to contamination and were located 

outside the study area. Negative controls are used to 

identify the reliability of contamination at or near a censoring level, and to ensure that sampling equipment is sterilized 

and that no contamination of the sample occurs in the field. 

Ground water from the study area was not used as a negative 

control because no single source could be guaranteed to be 

free of pathogens. Additionally, it was considered impractical to sterilize a sufficient volume of source water to 

create a secure supply of microbial-free water. Therefore, 

wells that were deep (greater than 500 ft) and distant from 

the study area were used as a probable virus-free source of 

negative control water. The two wells selected were located 

in St. Marys County, Maryland (fig. 1), and were part of a 

network of wells being monitored in a water-resource study 

(Klohe and Feehley, 2001). The two wells sampled were 

finished 575 ft and 600 ft below sea level. Neither negativecontrol sample contained detectable microbiological 

material. 

Field spikes provide information on sampling and 

analytical bias. Because the use of live attenuated poliovirus near a public water supply was considered an unacceptable health risk, field spikes were not collected for this 

study. 

Occurrence and Distribution of Viral 

Contamination 

Results from enteric virus, coliphage, bacteria, and 

nutrient contamination are shown in figure 3. All other data 

including microbiological data are presented in the 

Appendix. Twenty-nine percent of the environmental 

samples (26 out of 90), had detections for one or more fecalindicator bacteria (enterococci and (or) C. perfringens or 

E. coli). Nineteen of 90 samples contained total coliform 

bacteria. About 7 percent of the environmental samples had 

detections of bacteriophage (male-specific coliphage and 

(or) B. fragilis or somatic coliphage). The viral RNA for 

rotavirus was detected at site HA Bd 82. No sites were 

contaminated with culturable viruses. Three samples 

(BA Ac 154, BA Bd 239, and BA Df 356) had nitrate levels 

that were above the USEPA maximum contaminant level for 

drinking water of 10 mg/L (milligrams per liter). 

For statistical analysis, bacteria and coliphage results 

were recoded to a nominal scale of presence or absence. 

Any sample showing a positive result for one or multiple 

occurrences of bacterial contamination was identified as 

having a positive bacterial presence. A similar procedure 

was used for the three types of coliphage. These nominal 

data were compared among variables such as well depth, 

well age, casing depth, open interval, and all nutrient and 

field data using the large sample approximation of the ranksum test (Helsel and Hirsch, 1992). Kruskal-Wallis contingency tables for ordinal response variables were used to 

compare the categorical components such as on-site land use 

and on-site geology. Null hypotheses, that the distribution 

of data in each response category are the same, were rejected 

at the 95-percent confidence level (α = 0.05). 

Twenty-six of 90 samples were contaminated with fecalindicator bacteria (19 of 26 contained total coliform bacteria) 

and 6 of 90 samples (1 sample did not have coliphage or 

bacterial analysis performed) were contaminated with one 

or multiple forms of coliphage. A rank-sum analysis 

determined that no significant relation could be determined 

between the presence of bacteria and coliphage and virtually 

all continuous variables, including the concentration of total 

oxidized nitrogen. The rank-sum test did indicate that a 

significant difference was present between the mean 

temperature of the water sample measured in the field as a 

function of bacterial contamination (p = 0.035). Water 

temperature was measured continuously during the wellOccurrence and Distribution of Viral Contamination 9 
10 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
purging procedure. Once temperature stabilized (when 

there was less than a 0.2 °

C change between three measurements over a 3- to 5-minute sample interval), a final water 

temperature was recorded. Samples contaminated with 

fecal-indicator bacteria and (or) total coliform bacteria had a 

mean water temperature of 13.9 °

C. Samples in which no 

bacteria were detected had a mean water temperature of 

14.4 °

C. No significant relations were found among bacteria 

or coliphage contamination and well depth, well age, casing 

depth, or the open interval of the sampled well. 

Categorical data for on-site land use and on-site geology 

(rock type) were compared among nominal data for bacteria 

contamination using Kruskal-Wallis contingency tables. 

Land use was based on a MDE 1:63,360 scale map 

(Maryland Department of the Environment, 1994) and for 

this study, aggregated into four categories: agricultural, 

urban, residential, and forest. Site geology was based on 

1:24,000 scale maps produced by the Maryland Geological 

Survey (Cleaves, 1968). Aquifer lithologies used by Bolton 

(1998) in Baltimore County (carbonate, schist, gneiss, and 

mafic) were extended into Harford County and used to 

categorize geology for this study. No significant relations 

were found between bacteria contamination and any 

categorical data for land use or geology. 

Nineteen of the 26 water-supply wells that contained 

some form of bacteria were contaminated with total coliform 

bacteria. The concentration of total coliform bacteria in 

samples ranged from 1 to 1,046 cfu/100 mL. Kendall’s Tau, 

a test of monotonic correlation between two variables, was 

used to determine if the concentration of total coliform 

bacteria was related to continuous variables such as well 

depth, well age, casing depth, open interval, and all nutrient 

and field data (table 2). Kendall’s Tau is calculated on the 

ranked values of the data pairs and generally is more robust 

for variables that are non-normal, such as water-quality data. 

Tau generally will have lower values than other means that 

assess correlation with the same strength. Strong linear 

correlations of 0.9 or above correlate to Tau values of about 

0.7 and above (Helsel and Hirsch, 1992). 

A moderately strong, statistically significant correlation 

is present between the concentration of total coliform 

bacteria and pH as measured at NWQL (table 2). A somewhat weaker but still significant correlation is present between the age of the well, the pH as measured at WSLH, the 

acid-neutralizing capacity as measured at NWQL, and the 

concentration of total coliform bacteria. Finally, a moderate 

to weak but statistically significant correlation is present 

between sulfate concentration and the concentration of totalcoliform bacteria. 

The randomly distributed nature of the study design 

and the absence of detected culturable viruses (and a single 

detection of viral RNA) strongly indicate that viruses are 

not frequently detected among small, public water-supply 

wells in Baltimore and Harford Counties, Maryland. These 

same data, however, do not indicate which combination of 

environmental or anthropogenic factors are responsible for 

the absence of viral contamination. Inferences made 

beyond the study area on the occurrence and distribution of 

viruses in public-supply wells assume that the factors that 

contribute to the absence of viruses within the study area are 

present elsewhere. Similarly, Banks and others (2001) in a 

study of microbiological contamination of a similar population in two Maryland counties in the Coastal Plain 

Physiographic Province failed to identify any factors that 

related to viral occurrence even though 11 percent of the 

wells sampled showed some form of viral contamination. 

The incidence of fecal-indicator bacteria and total coliform 

bacteria contamination in both studies indicates that several 

environmentally controlled factors such as pH for total 

coliform bacteria in the Piedmont and a mean overall vulnerability-rank score for sites in the Coastal Plain correlate with 

the occurrence of bacteria in the sampled wells (Banks and 

others, 2001). These relations are not clearly understood, 

and should not be used as surrogates for the environmental 

occurrence of bacterial contamination. 

Occurrence and Distribution of Viral Contamination 11 
Table 2. Kendall’s Tau correlation coefficient for total coliform concentrations 

and continuous explanatory variables

 [USGS NWQL, U.S. Geological Survey National Water-Quality Laboratory; WSLH, Wisconsin State Laboratory of Hygiene; p, probability] 

Kendall’s Tau Significance Number 

Variable correlation of Correlation of 

coefficient (p value) samples 

pH of sample at USGS NWQL 0.473 0.005 19


Age of well .409 .017 19


Acid-neutralizing capacity at USGS NWQL .353 .038 19


pH at WSLH .350 .047 18


Sulfate, dissolved .341 .045 19


Acid-neutralizing capacity, field .333 .068 17


pH, field .329 .061 18


Water temperature, field .226 .208 19


Magnesium, dissolved .162 .342 19


Air temperature .085 .621 19


Specific conductance .078 .647 19


Phosphorus, dissolved .047 .797 19


Calcium, dissolved .018 .916 19


Cased interval of well .006 .972 19


Iron, dissolved .000 1.000 19


Chloride, dissolved -.102 .549 19


Oxygen, dissolved -.120 .492 18


Sodium, dissolved -.138 .418 19


Well depth -.177 .305 19


Uncased interval of well -.192 .260 19


Potassium, dissolved -.258 .130 19


Total oxidized nitrogen -.305 .073 19


Ammonia, dissolved -.372 .059 19


12 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Summary and Conclusions 

In 1999, the U.S. Geological Survey, in cooperation with 

the Maryland Department of the Environment and the 

Wisconsin State Laboratory of Hygiene, began to assess the 

occurrence and distribution of viral contamination in small 

(less than 10,000 gallons per day) public water-supply wells 

in Baltimore and Harford Counties, Maryland. 

Ninety sites were selected based on a method that used 

an inclusion probability proportional to an arbitrary weight 

for each county. An additional site, selected randomly in 

Baltimore County, also was sampled. Forty-six sampling 

sites were in Baltimore County, and 45 sampling sites were 

in Harford County. 

None of the 91 environmental samples contained culturable viruses; however, viral ribonucleic acid for rotavirus 

was detected at one site in Harford County. These data 

indicate that viruses are not frequently found in small public 

water-supply wells in the Piedmont Physiographic Province 

of Baltimore and Harford Counties, Maryland. 

Twenty-nine percent of the environmental samples (26 

out of 90) had detections for one or more fecal-indicator 

bacteria and (or) total coliform bacteria. About 7 percent 

of the environmental samples had detections of bacteriophage. Three sites had nitrate levels that were above the 

U.S. Environmental Protection Agency maximum contaminant level for drinking water (10 milligrams per liter). 

A statistical analysis determined that no significant 

relation is present between the presence of bacteria and 

coliphage, and all variables except the mean temperature of 

the water sample as measured in the field. Additionally, the 

concentration of total coliform bacteria had a statistically 

significant, moderately strong correlation with the age of the 

well, the sulfate concentration, and sample pH as measured 

at the U.S. Geological Survey National Water-Quality 

Laboratory in Denver, Colorado and the sample pH as 

measured at the Wisconsin State Laboratory of Hygiene. 

These relations are not clearly understood and should not be 

used as surrogates for the environmental occurrence of 

bacterial contamination. 

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Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000 

[cfu/mL, colony-forming units per milliliter; pfu/mL, plaque-forming units per milliliter; °C, degrees Celsius; μS/cm, microsiemens per

 centimeter; mg/L, milligrams per liter; NGVD, National Geodetic Vertical Datum of 1929, also referred to as sea level; <, less than;

 n/a, not applicable; ND, not detected; –, no data collected; P, present; E, estimated value (not quantitative); R, replicate sample] 

Total 

coliforms, Escherichia Male- Bacteroides 

Local membrane coli, specific Somatic fragilis, Clostridium 

well Date filtered filtered coliphage coliphage bacteriophage perfringens 

number sampled (cfu/100mL) (cfu/100mL) (pfu/1,000mL) (pfu/500mL) (pfu/500mL) (cfu/200mL) 

BA Ab 53 10/10/2000 <1 <1 ND ND ND <1 

BA Ac 154 11/01/2000 1 <1 – – ND <1 

BA Ad 150 09/18/2000 <1 <1 P ND ND <1 

BA Bc 276 08/21/2000 <1 <1 – – ND <1 

BA Bc 277 10/30/2000 <1 <1 ND ND ND <1 

BA Bd 239 10/16/2000 <1 <1 ND ND ND <1 

BA Bd 240 10/25/2000 3 <1 ND ND ND <1 

BA Bd 241 11/01/2000 1 <1 ND ND ND <1 

BA Bd 242 11/06/2000 <1 <1 ND ND ND <1 

BA Be 39 09/19/2000 <1 <1 ND ND ND <1 

BA Cb 97 07/24/2000 119 <1 ND ND ND <1 

BA Cb 145 06/21/2000 <1 <1 ND ND ND <1 

BA Cc 167 08/08/2000 <1 <1 ND ND ND <1 

BA Cc 260 11/06/2000 <1 <1 ND ND ND <1 

BA Cc 261 11/09/2000 <1 <1 ND ND ND <1 

BA Cd 242 08/16/2000 <1 <1 ND ND ND <1 

BA Cd 243 08/16/2000 <1 <1 ND ND ND <1 

BA Cd 244 08/23/2000 <1 <1 ND ND ND <1 

BA Ce 317 06/13/2000 – – – – – – 

BA Ce 318 07/19/2000 <1 <1 ND ND ND <1 

BA Da 54 08/07/2000 358 <1 ND ND ND <1 

BA Db 262 10/30/2000 <1 <1 ND ND ND <1 

BA Db 263 11/09/2000 30 <1 ND ND ND <1 

BA Dc 454 05/03/2000 <1 <1 ND P ND <1 

BA Dc 455 05/01/2000 <1 <1 ND ND ND <1 

BA Dc 456 05/01/2000 <1 <1 ND ND ND <1 

BA Dc 457 05/09/2000 <1 <1 ND ND ND <1 

BA Dc 458 05/30/2000 <1 <1 ND ND ND <1 

BA Dc 459 05/30/2000 <1 <1 ND ND ND <1 

BA Dc 460 06/13/2000 <1 <1 ND ND ND <1 

16 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 101 public water-supply wells in Baltimore and 

Harford Counties, Maryland, April through October 2000--Continued

Calicivirus Local 

Enterococci Cell Cytopathic Hepatitis A genotypes well 

(cfu/100mL) culture effects Resolved virus Enterovirus Rotavirus I, II number 

<1 negative n/a n/a negative negative negative negative BA Ab 53 

<1 negative n/a n/a negative negative negative negative BA Ac 154 

<1 negative n/a n/a negative negative negative negative BA Ad 150 

<1 negative n/a n/a negative negative negative negative BA Bc 276 

<1 negative n/a n/a negative negative negative negative BA Bc 277 

<1 negative n/a n/a negative negative negative negative BA Bd 239 

<1 negative n/a n/a negative negative negative negative BA Bd 240 

<1 negative n/a n/a negative negative negative negative BA Bd 241 

<1 negative n/a n/a negative negative negative negative BA Bd 242 

<1 negative n/a n/a negative negative negative negative BA Be 39 

2 negative n/a n/a negative negative negative negative BA Cb 97 

<1 negative n/a n/a negative negative negative negative BA Cc 145 

<1 negative n/a n/a negative negative negative negative BA Cc 167 

<1 negative n/a n/a negative negative negative negative BA Cc 260 

<1 negative n/a n/a negative negative negative negative BA Cc 261 

<1 negative n/a n/a negative negative negative negative BA Cd 242 

<1 negative n/a n/a negative negative negative negative BA Cd 243 

<1 negative n/a n/a negative negative negative negative BA Cd 244 

– negative n/a n/a negative negative negative negative BA Ce 317 

<1 negative n/a n/a negative negative negative negative BA Ce 318 

<1 negative n/a n/a negative negative negative negative BA Da 54 

<1 negative n/a n/a negative negative negative negative BA Db 262 

<1 negative n/a n/a negative negative negative negative BA Db 263 

1 negative n/a n/a negative negative negative negative BA Dc 454 

<1 negative n/a n/a negative negative negative negative BA Dc 455 

2 negative n/a n/a negative negative negative negative BA Dc 456 

<1 negative n/a n/a negative negative negative negative BA Dc 457 

<1 negative n/a n/a negative negative negative negative BA Dc 458 

<1 negative n/a n/a negative negative negative negative BA Dc 459 

<1 negative n/a n/a negative negative negative negative BA Dc 460 

Appendix 17 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Total 

coliforms, Escherichia Male- Bacteroides 

Local membrane coli, specific Somatic fragilis, Clostridium 

well Date filtered filtered coliphage coliphage bacteriophage perfringens 

number sampled (cfu/100mL) (cfu/100mL) (pfu/1,000mL) (pfu/500mL) (pfu/500mL) (cfu/200mL) 

BA Dc 461 06/29/2000 <1 <1 ND ND ND <1 

BA Dc 462 10/31/2000 <1 <1 ND ND ND <1 

BA Dc 462 R 10/31/2000 <1 <1 ND ND ND <1 

BA Dc 463 11/13/2000 <1 <1 ND ND ND <1 

BA De 643 07/18/2000 <1 <1 ND ND ND <1 

BA De 644 08/30/2000 <1 <1 ND P ND <1 

BA De 645 08/30/2000 9 <1 ND ND ND <1 

BA Df 356 11/13/2000 <1 <1 ND ND ND <1 

BA Dg 118 04/25/2000 <1 <1 ND ND ND <1 

BA Dg 119 05/10/2000 <1 <1 ND ND ND <1 

BA Dg 120 05/08/2000 <1 <1 ND ND ND <1 

BA Dg 120 R 05/08/2000 <1 <1 ND ND ND <1 

BA Ea 92 04/10/2000 22 <1 ND ND ND <1 

BA Ea 96 09/20/2000 <1 <1 ND ND ND <1 

BA Ea 97 10/18/2000 <1 <1 ND ND ND <1 

BA Eb 292 04/10/2000 <1 <1 ND ND ND <1 

BA Eg 259 11/07/2000 <1 <1 ND ND ND <1 

BA Eg 259 R 11/07/2000 <1 <1 ND ND ND <1 

BA Fb 82 04/11/2000 28 <1 ND ND ND <1 

BA Fb 82 R 04/11/2000 27 <1 ND ND ND <1 

HA Ac 57 07/10/2000 1 <1 ND – ND <1 

HA Ac 58 09/11/2000 4 <1 ND ND ND <1 

HA Ac 59 10/25/2000 <1 <1 ND ND ND <1 

HA Ad 16 09/18/2000 <1 <1 ND ND ND <1 

HA Ba 88 10/17/2000 <1 <1 ND ND ND <1 

HA Bb 105 07/31/2000 <1 <1 ND ND ND <1 

HA Bb 106 08/28/2000 <1 <1 ND ND ND <1 

HA Bb 107 08/29/2000 <1 <1 ND P ND <1 

HA Bc 34 06/14/2000 <1 <1 ND ND ND <1 

HA Bc 34 R 06/14/2000 <1 <1 ND ND ND <1 

18 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 101 public water-supply wells in Baltimore and 

Harford Counties, Maryland, April through October 2000--Continued

Enterococci 

(cfu/100mL) 

Cell 

culture 

Cytopathic 

effects Resolved 

Hepatitis A 

virus Enterovirus Rotavirus 

Calicivirus 

genotypes 

I, II 

Local 

well 

number 

<1 

<1 

<1 

<1 

<1 

negative 

negative 

negative 

negative 

negative 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

BA Dc 461 

BA Dc 462 

BA Dc 462 R 

BA Dc 463 

BA De 643 

<1 

15 

<1 

<1 

1 

negative 

negative 

negative 

negative 

negative 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

BA De 644 

BA De 645 

BA Df 356 

BA Dg 118 

BA Dg 119 

<1 

<1 

1 

<1 

<1 

negative 

negative 

negative 

negative 

negative 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

BA Dg 120 

BA Dg 120 R 

BA Ea 92 

BA Ea 96 

BA Ea 97 

<1 

<1 

<1 

<1 

<1 

negative 

negative 

negative 

negative 

negative 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

BA Eb 292 

BA Eg 259 

BA Eg 259 R 

BA Fb 82 

BA Fb 82 R 

<1 

<1 

<1 

<1 

<1 

negative 

negative 

negative 

negative 

negative 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

HA Ac 57 

HA Ac 58 

HA Ac 59 

HA Ad 16 

HA Ba 88 

<1 

<1 

<1 

<1 

<1 

negative 

negative 

negative 

negative 

negative 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

n/a 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

negative 

HA Bb 105 

HA Bb 106 

HA Bb 107 

HA Bc 34 

HA Bc 34 R 

Appendix 19 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Total 

coliforms, Escherichia Male- Bacteroides 

Local membrane coli, specific Somatic fragilis, Clostridium 

well Date filtered filtered coliphage coliphage bacteriophage perfringens 

number sampled (cfu/100mL) (cfu/100mL) (pfu/1,000mL) (pfu/500mL) (pfu/500mL) (cfu/200mL) 

HA Bc 35 10/23/2000 <1 <1 ND ND ND <1 

HA Bd 82 07/31/2000 50 3 P ND P <1 

HA Bd 87 10/11/2000 <1 <1 ND ND ND <1 

HA Bd 88 10/17/2000 <1 <1 ND ND ND <1 

HA Be 40 10/24/2000 162 <1 ND ND ND <1 

HA Bf 19 09/06/2000 <1 <1 ND ND ND <1 

HA Bf 20 09/06/2000 <1 <1 ND – ND <1 

HA Ca 29 09/07/2000 <1 <1 ND ND ND <1 

HA Cb 286 07/12/2000 <1 <1 ND ND ND <1 

HA Cb 287 08/01/2000 <1 <1 ND ND ND <1 

HA Cb 288 08/08/2000 <1 <1 ND ND ND <1 

HA Cb 289 08/23/2000 1 <1 ND ND ND <1 

HA Cb 290 10/23/2000 <1 <1 ND ND ND <1 

HA Cc 196 06/19/2000 <1 <1 ND ND ND <1 

HA Cc 197 07/11/2000 <1 <1 ND ND ND <1 

HA Cc 197 R 07/11/2000 <1 <1 ND ND ND <1 

HA Cc 198 07/24/2000 <1 <1 ND ND ND <1 

HA Cc 199 08/22/2000 276 <1 ND ND ND 2 

HA Cc 200 09/07/2000 <1 <1 ND ND ND <1 

HA Cc 201 10/18/2000 2 <1 ND ND ND <1 

HA Cd 199 07/13/2000 <1 <1 ND ND ND <1 

HA Cd 200 07/17/2000 <1 <1 ND ND ND <1 

HA Cd 201 07/25/2000 <1 <1 ND ND ND <1 

HA Cd 201 R 07/25/2000 <1 <1 ND ND ND <1 

HA Ce 119 08/23/2000 1,046 <1 ND ND ND <1 

HA Ce 120 09/18/2000 <1 <1 ND ND ND <1 

HA Cf 171 07/20/2000 <1 <1 ND ND ND <1 

HA Cf 176 08/03/2000 <1 <1 ND ND ND <1 

HA Cf 176 R 08/03/2000 <1 <1 ND ND ND <1 

20 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 101 public water-supply wells in Baltimore and 

Harford Counties, Maryland, April through October 2000--Continued

Calicivirus Local 

Enterococci Cell Cytopathic Hepatitis A genotypes well 

(cfu/100mL) culture effects Resolved virus Enterovirus Rotavirus I, II number 

<1 negative n/a n/a negative negative negative negative HA Bc 35 

<1 negative n/a n/a negative negative positive negative HA Bd 82 

<1 negative n/a n/a negative negative negative negative HA Bd 87 

<1 negative n/a n/a negative negative negative negative HA Bd 88 

4 negative n/a n/a negative negative negative negative HA Be 40 

<1 negative n/a n/a negative negative negative negative HA Bf 19 

<1 negative n/a n/a negative negative negative negative HA Bf 20 

<1 negative n/a n/a negative negative negative negative HA Ca 29 

<1 negative n/a n/a negative negative negative negative HA Cb 286 

<1 negative n/a n/a negative negative negative negative HA Cb 287 

<1 negative n/a n/a negative negative negative negative HA Cb 288 

<1 negative n/a n/a negative negative negative negative HA Cb 289 

<1 negative n/a n/a negative negative negative negative HA Cb 290 

<1 negative n/a n/a negative negative negative negative HA Cc 196 

<1 negative n/a n/a negative negative negative negative HA Cc 197 

<1 negative n/a n/a negative negative negative negative HA Cc 197 R 

<1 negative n/a n/a negative negative negative negative HA Cc 198 

<1 negative n/a n/a negative negative negative negative HA Cc 199 

<1 negative n/a n/a negative negative negative negative HA Cc 200 

<1 negative n/a n/a negative negative negative negative HA Cc 201 

<1 negative n/a n/a negative negative negative negative HA Cd 199 

<1 negative n/a n/a negative negative negative negative HA Cd 200 

<1 negative n/a n/a negative negative negative negative HA Cd 201 

<1 negative n/a n/a negative negative negative negative HA Cd 201 R 

<1 negative n/a n/a negative negative negative negative HA Ce 119 

<1 negative n/a n/a negative negative negative negative HA Ce 120 

<1 negative n/a n/a negative negative negative negative HA Cf 171 

<1 negative n/a n/a negative negative negative negative HA Cf 176 

<1 negative n/a n/a negative negative negative negative HA Cf 176 R 

Appendix 21 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Total 

coliforms, Escherichia Male- Bacteroides 

Local membrane coli, specific Somatic fragilis, Clostridium 

well Date filtered filtered coliphage coliphage bacteriophage perfringens 

number sampled (cfu/100mL) (cfu/100mL) (pfu/1,000mL) (pfu/500mL) (pfu/500mL) (cfu/200mL) 

HA Cf 178 08/28/2000 <1 <1 ND ND ND <1 

HA Dc 121 05/24/2000 <1 <1 ND ND ND <1 

HA Dc 122 06/26/2000 3 <1 ND ND ND <1 

HA Dc 122 R 06/26/2000 2 <1 ND ND ND <1 

HA Dc 123 08/01/2000 2 <1 ND P ND <1 

HA Dc 124 10/16/2000 <1 <1 ND ND ND <1 

HA Dd 108 05/02/2000 <1 <1 ND ND ND <1 

HA De 297 05/31/2000 <1 <1 ND ND ND <1 

HA De 297 R 05/31/2000 <1 <1 ND ND ND <1 

HA De 298 06/20/2000 <1 <1 ND ND ND <1 

HA De 299 07/18/2000 <1 <1 ND ND ND <1 

HA De 300 10/11/2000 <1 <1 ND ND ND <1 

22 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 101 public water-supply wells in Baltimore and 

Harford Counties, Maryland, April through October 2000--Continued

Calicivirus Local 

Enterococci Cell Cytopathic Hepatitis A genotypes well 

(cfu/100mL) culture effects Resolved virus Enterovirus Rotavirus I, II number 

<1 negative n/a n/a negative negative negative negative HA Cf 178 

1 negative n/a n/a negative negative negative negative HA Dc 121 

<1 negative n/a n/a negative negative negative negative HA Dc 122 

<1 negative n/a n/a negative negative negative negative HA Dc 122 R 

<1 negative n/a n/a negative negative negative negative HA Dc 123 

<1 negative n/a n/a negative negative negative negative HA Dc 124 

2 negative n/a n/a negative negative negative negative HA Dd 108 

<1 negative n/a n/a negative negative negative negative HA De 297 

<1 negative n/a n/a negative negative negative negative HA De 297 R 

<1 negative n/a n/a negative negative negative negative HA De 298 

<1 negative n/a n/a negative negative negative negative HA De 299 

<1 negative n/a n/a negative negative negative negative HA De 300 

Appendix 23 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Local 

well 

number 

Date 

sampled 

Viral a 

presence 

Bacterial b 

presence 

Bacteriophage c 

presence 

Water 

temperature 

( °

C) 

Air 

temperature 

( °

C) 

Specific 

conductance, 

laboratory 

(μS/cm) 

Oxygen, 

dissolved 

(mg/L) 

BA Ab 53 

BA Ac 154 

BA Ad 150 

BA Bc 276 

BA Bc 277 

10/10/2000 

11/01/2000 

09/18/2000 

08/21/2000 

10/30/2000 

no 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

yes 

no 

no 

13 

13 

14 

14.5 

15 

12.5 

9.5 

23 

20 

11 

– 

– 

– 

– 

– 

8.91 

9.37 

5.84 

8.90 

7.70 

BA Bd 239 

BA Bd 240 

BA Bd 241 

BA Bd 242 

BA Be 39 

10/16/2000 

10/25/2000 

11/01/2000 

11/06/2000 

09/19/2000 

no 

no 

no 

no 

no 

no 

yes 

yes 

no 

no 

no 

no 

no 

no 

no 

14 

14.5 

12.5 

14 

13.5 

15.5 

20.5 

13.5 

6.5 

18.5 

– 

– 

– 

– 

– 

6.84 

9.55 

9.20 

9.28 

2.87 

BA Cb 97 

BA Cb 145 

BA Cc 167 

BA Cc 260 

BA Cc 261 

07/24/2000 

06/21/2000 

08/08/2000 

11/06/2000 

11/09/2000 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

no 

no 

no 

no 

14 

13 

18 

12.5 

12 

19 

26 

34 

12.5 

15 

– 

306 

– 

127.4 

– 

9.17 

6.04 

7.77 

8.46 

5.39 

BA Cd 242 

BA Cd 243 

BA Cd 244 

BA Ce 317 

BA Ce 318 

08/16/2000 

08/16/2000 

08/23/2000 

06/13/2000 

07/19/2000 

no 

no 

no 

no 

no 

no 

no 

no 

– 

no 

no 

no 

no 

– 

no 

15.5 

13.4 

13.5 

16.5 

13.5 

28 

28 

23 

19 

21 

– 

– 

– 

1,535 

29 

3.25 

2.90 

7.42 

8.42 

9.37 

BA Da 54 

BA Db 262 

BA Db 263 

BA Dc 454 

BA Dc 455 

08/07/2000 

10/30/2000 

11/09/2000 

05/03/2000 

05/01/2000 

no 

no 

no 

no 

no 

yes 

no 

yes 

yes 

no 

no 

no 

no 

yes 

no 

13 

13 

13.5 

13 

13.5 

31 

12 

14.5 

21 

19 

136 

85.8 

110 

172 

403 

1.32 

7.64 

4.53 

8.93 

6.57 

BA Dc 456 

BA Dc 457 

BA Dc 458 

BA Dc 459 

BA Dc 460 

05/01/2000 

05/09/2000 

05/30/2000 

05/30/2000 

06/13/2000 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

no 

no 

no 

no 

13.5 

14.5 

14 

13 

14 

19 

28.5 

14 

16 

21 

410 

50 

430 

145 

468 

6.65 

7.90 

7.30 

7.81 

9.16 

24 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 101 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through October 2000--Continued

Depth Depth of 

pH Nitrogen, of well casing 

whole water, Acid-neutral- ammonia plus Nitrite Elevation of (feet (feet 

field izing capacity, organic, plus nitrate, Phosphorus, land surface below below Local 

(standard field (mg/L total dissolved ortho (feet above land land well 

units) as CaCO3) (mg/L as N) (mg/L as N) (mg/L as P) NGVD) surface) surface) number 

5.78 12 E 0.05 2.26 <0.02 760 140 52 BA Ab 53 

5.39 9.5 < .08 11.05 < .02 780 125 40 BA Ac 154 

5.15 9 E .07 7.66 .01 820 125 42 BA Ad 150 

5.40 7 < .10 2.39 < .01 600 350 62 BA Bc 276 

5.21 12 < .08 8.47 .02 800 305 47 BA Bc 277 

5.58 18 E .05 10.09 < .02 650 150 57 BA Bd 239 

6.50 34 < .08 2.33 .03 580 400 100 BA Bd 240 

5.78 26 < .08 6.38 .02 620 500 63 BA Bd 241 

5.30 3.5 < .08 9.63 < .02 660 170 25 BA Bd 242 

5.69 52 < .10 1.84 .02 600 300 80 BA Be 39 

6.02 14.5 < .10 5.00 .04 590 142 50 BA Cb 97 

6.07 42 < .10 2.17 .02 720 125 77 BA Cb 145 

6.03 32 < .10 6.35 < .01 450 250 30 BA Cc 167 

5.99 24.5 < .08 4.29 .03 380 116 79 BA Cc 260 

6.13 36 < .08 .68 < .02 450 294 – BA Cc 261 

6.93 90 < .10 .19 < .01 460 225 24 BA Cd 242 

6.37 100 .18 .14 < .01 460 400 34 BA Cd 243 

5.68 72.5 E .08 4.94 < .01 300 175 39 BA Cd 244 

5.52 8.5 E .07 1.16 < .01 680 200 36 BA Ce 317 

6.56 8 E .08 .98 < .01 600 250 24 BA Ce 318 

– – E .05 2.70 < .01 580 250 60 BA Da 54 

6.00 19.5 .14 2.58 .03 560 145 50 BA Db 262 

5.82 28 < .08 3.88 .05 640 118 67 BA Db 263 

6.52 58 E .06 1.09 < .01 480 100 69 BA Dc 454 

6.05 35 < .10 .94 < .01 540 525 50 BA Dc 455 

6.15 34 < .10 .93 < .01 540 250 25 BA Dc 456 

5.70 8 E .07 1.86 < .01 670 308 66 BA Dc 457 

7.68 164 E .06 2.23 < .01 370 250 45 BA Dc 458 

8.30 64 < .10 .25 .02 380 300 64 BA Dc 459 

7.76 215 E .05 .89 < .01 370 223 50 BA Dc 460 

Appendix 25 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Local 

well 

number 

Date 

sampled 

Viral a 

presence 

Bacterial b 

presence 

Bacteriophage c 

presence 

Water 

temperature 

( °

C) 

Air 

temperature 

( °

C) 

Specific 

conductance, 

laboratory 

(μS/cm) 

Oxygen, 

dissolved 

(mg/L) 

BA Dc 461 

BA Dc 462 

BA Dc 462 R 

BA Dc 463 

BA De 643 

06/29/2000 

10/31/2000 

10/31/2000 

11/13/2000 

07/18/2000 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

13.5 

13.6 

13.6 

15 

15 

25 

15.5 

15.5 

11 

31 

90 

765 

– 

178 

421 

7.55 

6.09 

6.09 

6.58 

1.50 

BA De 644 

BA De 645 

BA Df 356 

BA Dg 118 

BA Dg 119 

08/30/2000 

08/30/2000 

11/13/2000 

04/25/2000 

05/10/2000 

no 

no 

no 

no 

no 

no 

yes 

no 

no 

yes 

yes 

no 

no 

no 

no 

13.5 

13 

16.5 

15 

13.5 

25 

21 

10.5 

10 

26 

134 

120 

470 

217 

356 

8.21 

6.08 

7.72 

2.69 

7.26 

BA Dg 120 

BA Dg 120 R 

BA Ea 92 

BA Ea 96 

BA Ea 97 

05/08/2000 

05/08/2000 

04/10/2000 

09/20/2000 

10/18/2000 

no 

no 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

no 

no 

15 

15 

14 

14 

16 

29 

29 

15 

22 

15.5 

260 

– 

190 

409 

99.1 

4.75 

4.75 

7.23 

3.77 

7.10 

BA Eb 292 

BA Eg 259 

BA Eg 259 R 

BA Fb 82 

BA Fb 82 R 

04/10/2000 

11/07/2000 

11/07/2000 

04/11/2000 

04/11/2000 

no 

no 

no 

no 

no 

no 

no 

no 

yes 

yes 

no 

no 

no 

no 

no 

13.5 

14 

14 

15 

15 

9.5 

10 

10 

10 

10 

193 

915 

– 

1,475 

– 

7.29 

– 

– 

2.75 

2.75 

HA Ac 57 

HA Ac 58 

HA Ac 59 

HA Ad 16 

HA Ba 88 

07/10/2000 

09/11/2000 

10/25/2000 

09/18/2000 

10/17/2000 

no 

no 

no 

no 

no 

yes 

yes 

no 

no 

no 

no 

no 

no 

no 

no 

14.5 

13 

15 

12 

14.5 

30 

25 

20.5 

18 

13 

– 

– 

– 

– 

– 

3.35 

8.75 

5.49 

10.05 

6.80 

HA Bb 105 

HA Bb 106 

HA Bb 107 

HA Bc 34 

HA Bc 34 R 

07/31/2000 

08/28/2000 

08/29/2000 

06/14/2000 

06/14/2000 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

yes 

no 

no 

15 

16.5 

13.5 

13 

13 

30 

23 

24 

20 

20 

– 

– 

– 

– 

– 

1.09 

8.83 

9.61 

9.05 

9.05 

26 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 101 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through October 2000--Continued

pH 

whole water, 

field 

(standard 

units) 

Acid-neutralizing capacity, 

field (mg/L 

as CaCO3) 

Nitrogen, 

ammonia plus 

organic, 

total 

(mg/L as N) 

Nitrite 

plus nitrate, 

dissolved 

(mg/L as N) 

Phosphorus, 

ortho 

(mg/L as P) 

Elevation of 

land surface 

(feet above 

NGVD) 

Depth 

of well 

(feet 

below 

land 

surface) 

Depth of 

casing 

(feet 

below 

land 

surface) 

Local 

well 

number 

5.68 

7.27 

7.30 

7.98 

6.75 

14 

280 

284 

110 

41 

<0.10 

< .08 

– 

< .08 

< .10 

0.44 

3.62 

– 

1.21 

.07 

0.02 

< .02 

– 

E .01 

< .01 

660 

400 

400 

600 

490 

180 

200 

200 

300 

250 

– 

30 

30 

93 

46 

BA Dc 461 

BA Dc 462 

BA Dc 462 R 

BA Dc 463 

BA De 643 

5.60 

5.35 

6.78 

6.25 

5.80 

24 

19 

160 

78 

34 

< .10 

E .06 

E .04 

E .06 

.11 

3.03 

1.00 

10.28 

< .05 

5.00 

.05 

< .01 

.03 

< .01 

< .01 

500 

500 

260 

100 

110 

294 

150 

72 

125 

200 

20 

20 

22 

34 

– 

BA De 644 

BA De 645 

BA Df 356 

BA Dg 118 

BA Dg 119 

6.01 

5.94 

6.75 

6.48 

6.13 

50 

51 

52 

84 

29 

E .08 

– 

< .10 

< .10 

E .06 

6.61 

– 

3.25 

4.35 

2.93 

< .01 

– 

.02 

< .01 

.05 

300 

300 

540 

600 

480 

185 

185 

420 

500 

294 

47 

47 

44 

70 

58 

BA Dg 120 

BA Dg 120 R 

BA Ea 92 

BA Ea 96 

BA Ea 97 

6.20 

6.70 

6.69 

6.90 

6.90 

54 

485 

475 

213 

217 

< .10 

4.24 

– 

.10 

.11 

3.07 

< .05 

– 

2.85 

2.63 

.04 

< .02 

– 

< .01 

< .01 

480 

60 

60 

100 

100 

150 

115 

115 

200 

200 

58 

100 

100 

120 

120 

BA Eb 292 

BA Eg 259 

BA Eg 259 R 

BA Fb 82 

BA Fb 82 R 

5.47 

5.80 

5.94 

5.68 

6.36 

– 

32 

12 

14 

29.5 

E .05 

< .10 

< .08 

< .10 

< .08 

8.46 

8.13 

7.93 

1.17 

4.68 

< .01 

.07 

E .01 

.03 

< .02 

500 

500 

580 

300 

740 

175 

250 

60 

175 

108 

21 

68 

34 

38 

20 

HA Ac 57 

HA Ac 58 

HA Ac 59 

HA Ad 16 

HA Ba 88 

5.95 

6.65 

4.83 

5.85 

5.66 

15 

95 

3 

9 

8 

E .06 

E .05 

E .05 

< .10 

< .10 

7.23 

2.46 

6.16 

1.04 

1.04 

< .01 

.01 

< .01 

.01 

.01 

620 

550 

550 

300 

300 

350 

250 

300 

150 

150 

32 

39 

40 

20 

20 

HA Bb 105 

HA Bb 106 

HA Bb 107 

HA Bc 34 

HA Bc 34 R 

Appendix 27 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Local 

well 

number 

Date 

sampled 

Viral a 

presence 

Bacterial b 

presence 

Bacteriophage c 

presence 

Water 

temperature 

( °

C) 

Air 

temperature 

( °

C) 

Specific 

conductance, 

laboratory 

(μS/cm) 

Oxygen, 

dissolved 

(mg/L) 

HA Bc 35 

HA Bd 82 

HA Bd 87 

HA Bd 88 

HA Be 40 

10/23/2000 

07/31/2000 

10/11/2000 

10/17/2000 

10/24/2000 

no 

yes 

no 

no 

no 

no 

yes 

no 

no 

yes 

no 

yes 

no 

no 

no 

14 

15 

14 

15.5 

14 

14 

30 

24 

14.5 

13 

– 

– 

– 

– 

– 

6.00 

16.43 

8.70 

3.14 

4.54 

HA Bf 19 

HA Bf 20 

HA Ca 29 

HA Cb 286 

HA Cb 287 

09/06/2000 

09/06/2000 

09/07/2000 

07/12/2000 

08/01/2000 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

no 

13 

15 

13 

14.5 

15 

19 

19.5 

19 

27 

31 

– 

– 

– 

– 

– 

8.36 

1.82 

6.70 

1.90 

3.69 

HA Cb 288 

HA Cb 289 

HA Cb 290 

HA Cc 196 

08/08/2000 

08/23/2000 

10/23/2000 

06/19/2000 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

no 

15 

14 

15 

14.5 

32 

19 

11 

20 

– 

– 

– 

317.6 

5.68 

3.49 

5.48 

18.22 

HA Cc 197 

HA Cc 197 R 

HA Cc 198 

HA Cc 199 

HA Cc 200 

07/11/2000 

07/11/2000 

07/24/2000 

08/22/2000 

09/07/2000 

no 

no 

no 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

no 

13.5 

13.5 

16.5 

14.5 

14.5 

29 

29 

19 

23.5 

14.5 

310 

– 

– 

582 

– 

5.26 

5.26 

1.77 

3.00 

7.50 

HA Cc 201 

HA Cd 199 

HA Cd 200 

HA Cd 201 

HA Cd 201 R 

10/18/2000 

07/13/2000 

07/17/2000 

07/25/2000 

07/25/2000 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

no 

no 

no 

no 

14.5 

17 

15 

15 

15 

16 

24 

25.5 

21.5 

21.5 

168.6 

237 

– 

– 

– 

3.13 

– 

8.23 

– 

– 

HA Ce 119 

HA Ce 120 

HA Cf 171 

HA Cf 176 

HA Cf 176 R 

08/23/2000 

09/18/2000 

07/20/2000 

08/03/2000 

08/03/2000 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

no 

no 

no 

no 

15.5 

15 

14 

14 

14 

23 

14 

28 

29 

29 

– 

– 

78 

150 

– 

6.60 

5.57 

1.38 

3.10 

3.10 

28 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 101 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through October 2000--Continued

Depth Depth of 

pH Nitrogen, of well casing 

whole water, Acid-neutral- ammonia plus Nitrite Elevation of (feet (feet 

field izing capacity, organic, plus nitrate, Phosphorus, land surface below below Local 

(standard field (mg/L total dissolved ortho (feet above land land well 

units) as CaCO3) (mg/L as N) (mg/L as N) (mg/L as P) NGVD) surface) surface) number 

5.96 41 <0.08 7.24 0.03 540 500 75 HA Bc 35 

7.00 80 < .10 2.77 < .01 450 64 55 HA Bd 82 

6.30 49 < .08 4.56 .03 380 199 42 HA Bd 87 

6.45 87 E .05 4.54 < .02 440 62 62 HA Bd 88 

7.11 116 < .08 1.71 E .02 410 250 50 HA Be 40 

6.61 52 < .10 .65 < .01 150 200 20 HA Bf 19 

7.77 101 E .05 .06 < .01 150 405 24 HA Bf 20 

5.60 15.5 E .06 6.78 .03 550 100 40 HA Ca 29 

7.35 41 < .10 .08 < .01 520 162 75 HA Cb 286 

6.59 120 < .10 1.88 .01 570 550 42 HA Cb 287 

6.08 27 < .10 5.38 .01 540 200 51 HA Cb 288 

5.61 28 .14 3.17 .03 500 280 58 HA Cb 289 

5.36 15 < .08 5.83 E .01 520 225 79 HA Cb 290 

6.33 108 < .10 2.60 .03 360 107 20 HA Cc 196 

6.59 – < .10 4.09 .03 460 300 111 HA Cc 197 

6.59 – < .10 4.05 .03 460 300 111 HA Cc 197 R 

7.51 207 E .07 1.82 .01 480 59 25 HA Cc 198 

6.61 182 E .06 .33 .04 450 205 22 HA Cc 199 

5.33 11.5 < .10 3.08 < .01 400 300 30 HA Cc 200 

5.97 34.5 E .07 3.95 .05 450 150 20 HA Cc 201 

5.82 22 .33 1.02 < .01 240 200 45 HA Cd 199 

5.94 14 E .06 2.92 .04 400 200 80 HA Cd 200 

5.68 20 < .10 5.75 .01 400 150 47 HA Cd 201 

5.68 20 < .10 6.28 .01 400 150 47 HA Cd 201 R 

5.65 54 E .07 8.16 .02 350 39 24 HA Ce 119 

6.60 45 .16 7.60 .02 400 125 43 HA Ce 120 

6.64 30 < .10 .69 < .01 42 144 112 HA Cf 171 

6.35 31 < .10 2.61 .02 40 70 60 HA Cf 176 

6.35 31 < .10 2.57 .02 40 70 60 HA Cf 176 R 

Appendix 29 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Local 

well 

number 

Date 

sampled 

Viral a 

presence 

Bacterial b 

presence 

Bacteriophage c 

presence 

Water 

temperature 

( °

C) 

Air 

temperature 

( °

C) 

Specific 

conductance, 

laboratory 

(μS/cm) 

Oxygen, 

dissolved 

(mg/L) 

HA Cf 178 

HA Dc 121 

HA Dc 122 

HA Dc 122 R 

HA Dc 123 

08/28/2000 

05/24/2000 

06/26/2000 

06/26/2000 

08/01/2000 

no 

no 

no 

no 

no 

no 

yes 

yes 

yes 

yes 

no 

no 

no 

no 

yes 

16 

13.5 

13.5 

13.5 

14 

26 

21 

27 

27 

31 

– 

204 

105 

– 

617 

8.82 

7.20 

– 

– 

4.52 

HA Dc 124 

HA Dd 108 

HA De 297 

HA De 297 R 

10/16/2000 

05/02/2000 

05/31/2000 

05/31/2000 

no 

no 

no 

no 

no 

yes 

no 

no 

no 

no 

no 

no 

15 

14 

14.5 

14.5 

17 

20.5 

15.5 

15.5 

219 

254 

387 

– 

.67 

2.88 

4.42 

4.42 

HA De 298 

HA De 299 

HA De 300 

06/20/2000 

07/18/2000 

10/11/2000 

no 

no 

no 

no 

no 

no 

no 

no 

no 

15 

16 

14 

26 

31 

14.5 

251 

229 

18.4 

1.08 

.60 

5.69 

a. Viral presence; positive cell culture or the positive presence of Hepatitis A, Enterovirus, Rotavirus, or Calicivirus Ribonucleic acid. 

b. Bacterial presence; positive presence of either Total coliforms, Escherichia coli, or Enterococci. 

c. Bacteriophage presence; positive presence of either Male-specific coliphage, Somatic coliphage, or Bacteroides fragilis. 

30 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 101 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through October 2000--Continued

Depth Depth of 

pH Nitrogen, of well casing 

whole water, Acid-neutral- ammonia plus Nitrite Elevation of (feet (feet 

field izing capacity, organic, plus nitrate, Phosphorus, land surface below below Local 

(standard field (mg/L total dissolved ortho (feet above land land well 

units) as CaCO3) (mg/L as N) (mg/L as N) (mg/L as P) NGVD) surface) surface) number 

5.81 10 <0.10 1.64 <0.01 400 110 65 HA Cf 178 

6.36 46 < .10 4.23 .03 140 200 60 HA Dc 121 

6.18 26 < .10 2.24 .03 380 125 53 HA Dc 122 

6.18 26 < .10 2.32 .03 380 125 53 HA Dc 122 R 

7.04 80 < .10 4.42 < .01 300 150 30 HA Dc 123 

6.89 106 E .05 < .05 < .02 180 350 90 HA Dc 124 

7.94 120 .15 < .05 .02 – 300 56 HA Dd 108 

7.75 143 E .06 < .05 < .01 – 245 64 HA De 297 

7.72 142 – – – – 245 64 HA De 297 R 

7.14 125 < .10 < .05 .05 160 200 60 HA De 298 

7.30 110 E .06 < .05 < .01 100 400 72 HA De 299 

5.45 5.5 < .08 E .02 < .02 8 170 163 HA De 300 

Appendix 31 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Local 

well 

number 

Date 

sampled 

Length of 

open hole 

(feet) 

Acid-neutralizing capacity, 

bicarbonate, 

field (mg/L 

as CaCO3) 

Nitrogen 

ammonia, 

dissolved 

(mg/L as N) 

Nitrite, 

dissolved 

(mg/L as N) 

Nitrogen, 

ammonia plus 

organic, 

dissolved 

(mg/L as N) 

Phosphorus, 

dissolved 

(mg/L as P) 

Phosphorus, 

total 

(mg/L as P) 

BA Ab 53 

BA Ac 154 

BA Ad 150 

BA Bc 276 

BA Bc 277 

10/10/2000 

11/01/2000 

09/18/2000 

08/21/2000 

10/30/2000 

88 

85 

83 

288 

258 

14.6 

11.6 

11 

9 

14.6 

<0.04 

< .04 

< .02 

< .02 

< .04 

<0.01 

< .01 

< .01 

< .01 

< .01 

<0.10 

< .10 

< .10 

< .10 

< .10 

<0.01 

E .01 

.01 

< .01 

.03 

0.11 

.01 

.01 

< .01 

.03 

BA Bd 239 

BA Bd 240 

BA Bd 241 

BA Bd 242 

BA Be 39 

10/16/2000 

10/25/2000 

11/01/2000 

11/06/2000 

09/19/2000 

93 

300 

437 

145 

220 

22 

41.5 

31.7 

4.3 

63 

< .04 

< .04 

< .04 

< .04 

< .02 

< .01 

< .01 

< .01 

< .01 

< .01 

< .10 

E .05 

< .10 

E .07 

< .10 

< .01 

.03 

.01 

< .01 

.02 

.01 

.04 

.01 

E .00 

.03 

BA Cb 97 

BA Cb 145 

BA Cc 167 

BA Cc 260 

BA Cc 261 

07/24/2000 

06/21/2000 

08/08/2000 

11/06/2000 

11/09/2000 

92 

48 

220 

37 

– 

17 

51 

39 

29.9 

44 

< .02 

< .02 

< .02 

< .04 

< .04 

< .01 

< .01 

< .01 

< .01 

< .01 

E .06 

< .10 

< .10 

E .08 

E .06 

.05 

.03

E .00 

.04 

E .00 

.05 

.03 

< .01 

.05 

.01 

BA Cd 242 

BA Cd 243 

BA Cd 244 

BA Ce 317 

BA Ce 318 

08/16/2000 

08/16/2000 

08/23/2000 

06/13/2000 

07/19/2000 

201 

366 

136 

164 

226 

110 

122 

88 

10 

10 

< .02 

< .02 

< .02 

< .02 

< .02 

< .01 

< .01 

< .01 

< .01 

< .01 

< .10 

< .10 

< .10 

E .05 

< .10 

.01 

< .01 

.01 

< .01 

.01 

E .00 

.02 

E .01 

< .01 

.01 

BA Da 54 

BA Db 262 

BA Db 263 

BA Dc 454 

BA Dc 455 

08/07/2000 

10/30/2000 

11/09/2000 

05/03/2000 

05/01/2000 

190

95 

51 

31 

475 

– 

23.8 

34 

71 

43 

< .02 

< .04 

< .04 

< .02 

< .02 

.03 

< .01 

< .01 

< .01 

< .01 

< .10

< .10 

< .10 

< .10

< .10 

.01 

.04 

.05 

.01 

< .01 

.01 

.04 

.05 

E .01 

E .00 

BA Dc 456 

BA Dc 457 

BA Dc 458 

BA Dc 459 

BA Dc 460 

05/01/2000 

05/09/2000 

05/30/2000 

05/30/2000 

06/13/2000 

225 

242 

205 

236 

173 

41 

10 

200 

78 

262 

< .02 

< .02 

< .02 

< .02 

< .02 

< .01 

< .01 

< .01 

< .01 

< .01 

< .10 

< .10 

< .10 

< .10 

< .10 

< .01 

< .01 

< .01 

.02 

< .01 

E .00 

< .01 

< .01 

.02 

< .01 

32 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through November 2000—Continued

pH pH 

whole water, whole water, 

Calcium, Magnesium, Sodium, Potassium, Chloride, Sulfate, Iron, Denver Wisconsin 

dissolved dissolved dissolved dissolved dissolved dissolved dissolved laboratory laboratory Local 

(mg/L (mg/L (mg/L (mg/L (mg/L (mg/L (mg/L (standard (standard well 

as Ca) as Mg) as Na) as K) as Cl) as SO4) as Fe) units) units) number 

5.86 3.25 19.05 1.02 38.18 0.54 35.09 5.78 5.78 BA Ab 53 

14.21 6.90 8.82 1.20 23.27 2.36 <10 5.46 5.39 BA Ac 154 

18.45 12.45 78.80 7.32 158.02 27.32 E 9.15 5.25 5.19 BA Ad 150 

2.25 2.57 2.52 1.47 5.44 .62 16.07 6.21 5.40 BA Bc 276 

12.84 6.72 13.73 1.06 33.75 .68 <10 5.34 5.21 BA Bc 277 

57.29 30.50 86.16 5.93 306.33 7.89 32.70 7.33 5.58 BA Bd 239 

25.13 10.75 12.98 1.04 68.94 .43 <10 6.24 6.50 BA Bd 240 

9.86 4.65 4.07 2.46 7.65 .93 <10 5.83 5.78 BA Bd 241 

5.90 7.78 7.56 2.48 19.33 .30 <10 5.73 5.30 BA Bd 242 

13.27 3.26 7.67 1.38 5.43 1.45 <10 6.00 5.69 BA Be 39 

15.80 6.70 9.02 1.33 28.18 15.07 <10 6.22 6.02 BA Cb 97 

23.23 7.44 16.46 3.40 60.39 1.62 16.68 6.47 6.57 BA Cb 145 

23.50 10.33 6.53 3.13 34.36 10.66 25.10 6.07 6.03 BA Cc 167 

15.44 5.21 7.44 1.16 7.59 24.08 E 5.13 6.24 5.91 BA Cc 260 

29.61 14.92 31.93 3.53 114.97 7.47 <10 6.33 6.13 BA Cc 261 

35.13 6.55 10.02 2.33 18.01 21.92 E 5.42 7.08 – BA Cd 242 

36.50 6.60 10.03 2.33 17.49 22.05 <10 7.57 – BA Cd 243 

25.70 9.97 15.69 5.29 16.02 31.78 <10 6.41 5.65 BA Cd 244 

44.06 23.75 206.34 7.37 486.50 15.09 E 6.38 5.52 6.24 BA Ce 317 

1.27 .84 2.24 .96 2.53 < .31 <10 6.20 6.56 BA Ce 318 

7.69 5.76 6.65 2.61 6.01 10.15 <10 7.01 7.00 BA Da 54 

8.52 3.16 5.45 2.00 4.00 14.94 E 7.53 6.39 6.00 BA Db 262 

10.41 4.39 8.57 2.10 7.95 9.54 <10 6.12 5.82 BA Db 263 

17.86 5.40 5.29 2.62 10.11 1.46 <10 6.63 6.50 BA Dc 454 

32.71 13.59 11.15 4.11 88.42 8.52 116.54 6.31 – BA Dc 455 

32.58 13.64 11.19 4.03 86.54 8.53 133.81 6.65 – BA Dc 456 

2.13 1.66 3.51 1.34 2.31 3.79 E 6.20 5.92 6.31 BA Dc 457 

63.23 12.49 4.45 1.22 15.62 9.39 <10 7.63 7.64 BA Dc 458 

16.93 5.94 1.83 1.50 3.11 1.30 <10 8.11 7.96 BA Dc 459 

44.24 23.67 1.83 2.47 4.64 3.54 <10 7.56 7.77 BA Dc 460 

Appendix 33 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Local 

well 

number 

Date 

sampled 

Length of 

open hole 

(feet) 

Acid-neutralizing capacity, 

bicarbonate, 

field (mg/L 

as CaCO3) 

Nitrogen 

ammonia, 

dissolved 

(mg/L as N) 

Nitrite, 

dissolved 

(mg/L as N) 

Nitrogen, 

ammonia plus 

organic, 

dissolved 

(mg/L as N) 

Phosphorus, 

dissolved 

(mg/L as P) 

Phosphorus, 

total 

(mg/L as P) 

BA Dc 461 

BA Dc 462 

BA Dc 462 R 

BA Dc 463 

BA De 643 

06/29/2000 

10/31/2000 

10/31/2000 

11/13/2000 

07/18/2000 

– 

170 

170 

207 

204 

17 

342 

347 

134 

50 

<0.02 

< .04 

– 

< .04 

< .02 

<0.01 

< .01 

– 

< .01 

< .01 

<0.10 

< .10 

– 

< .10 

< .10 

0.03 

< .01 

– 

.01 

< .01 

0.03 

< .01 

– 

.01 

.15 

BA De 644 

BA De 645 

BA Df 356 

BA Dg 118 

BA Dg 119 

08/30/2000 

08/30/2000 

11/13/2000 

04/25/2000 

05/10/2000 

274 

130 

50 

91 

– 

29 

23 

195 

95 

41 

< .02 

< .02 

< .04 

< .02 

< .02 

< .01 

< .01 

< .01 

< .01 

< .01 

< .10 

< .10 

< .10 

< .10 

E .07 

.06 

E .01

.03 

E .00 

.01 

.06 

.01 

.03 

.02 

.01 

BA Dg 120 

BA Dg 120 R 

BA Ea 92 

BA Ea 96 

BA Ea 97 

05/08/2000 

05/08/2000 

04/10/2000 

09/20/2000 

10/18/2000 

138 

138 

376 

430 

236 

61 

– 

63.4 

102 

35.4 

< .02 

– 

< .02 

< .02 

< .04 

< .01 

– 

.01 

.01 

< .01 

E .07 

– 

< .10 

< .10 

E .05 

.01 

– 

.01 

.01 

.06 

E .00 

– 

.02 

.01 

.06 

BA Eb 292 

BA Eg 259 

BA Eg 259 R 

BA Fb 82 

BA Fb 82 R 

04/10/2000 

11/07/2000 

11/07/2000 

04/11/2000 

04/11/2000 

92 

15 

15 

80 

80 

66 

592 

580 

260 

– 

< .02 

3.23 

– 

< .02 

< .02 

< .01 

.01 

– 

< .01 

< .01 

< .10 

4.30 

– 

.11 

.11 

.05 

E .00 

– 

E .00 

E .00 

.05 

.01 

– 

E .00 

.01 

HA Ac 57 

HA Ac 58 

HA Ac 59 

HA Ad 16 

HA Ba 88 

07/10/2000 

09/11/2000 

10/25/2000 

09/18/2000 

10/17/2000 

154 

182 

26 

137 

88 

– 

39 

14.6

17 

36 

< .02 

< .02 

< .04 

< .02 

< .04 

< .01 

< .01 

< .01 

< .01 

< .01 

< .10 

< .10 

E .05 

< .10 

< .10 

.01 

.08 

.02 

.03 

E .00 

.01 

.09 

.02 

.03 

.01 

HA Bb 105 

HA Bb 106 

HA Bb 107 

HA Bc 34 

HA Bc 34 R 

07/31/2000 

08/28/2000 

08/29/2000 

06/14/2000 

06/14/2000 

318 

211 

260 

130 

130 

18 

116 

4 

11 

– 

< .02 

< .02 

< .02 

< .02 

< .02 

< .01 

< .01 

< .01 

< .01 

< .01 

.11 

< .10 

< .10 

< .10 

< .10 

.01 

< .01 

< .01 

.02 

.01 

.03 

.01 

< .01 

.01 

.01 

34 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through November 2000—Continued

Calcium, 

dissolved 

(mg/L 

as Ca) 

Magnesium, 

dissolved 

(mg/L 

as Mg) 

Sodium, 

dissolved 

(mg/L

 as Na) 

Potassium, 

dissolved 

(mg/L 

as K) 

Chloride, 

dissolved 

(mg/L 

as Cl) 

Sulfate, 

dissolved 

(mg/L 

as SO4) 

Iron, 

dissolved 

(mg/L 

as Fe) 

pH 

whole water, 

Denver 

laboratory 

(standard 

units) 

pH 

whole water, 

Wisconsin 

laboratory 

(standard 

units) 

Local 

well 

number 

3.26 

70.06 

– 

29.08 

27.01 

2.05 

40.49 

– 

7.86 

13.73 

9.16 

58.85 

– 

2.64 

13.56 

1.49 

1.09 

– 

1.82 

6.10 

15.83 

134.53 

– 

4.72 

74.15 

2.71 

11.67 

– 

3.04 

24.70 

<10 

<10 

– 

<10 

<10 

5.77 

7.29 

– 

7.81 

6.68 

5.68 

7.27 

7.30 

7.98 

6.75 

BA Dc 461 

BA Dc 462 

BA Dc 462 R 

BA Dc 463 

BA De 643 

8.62 

13.81 

58.93 

15.25 

19.52 

3.86 

5.41 

15.31 

8.73 

6.75 

7.31 

12.30 

28.63 

6.23 

33.14 

2.09 

2.53 

5.63 

3.07 

2.12 

12.87 

32.33 

28.31 

17.70 

57.84 

<0.31 

15.37 

44.45 

1.16 

17.15 

<10 

<10 

<10 

5,884 

19.44 

5.84 

5.63 

6.93 

6.45 

5.91 

5.60 

5.35 

6.63 

6.25 

6.21 

BA De 644 

BA De 645 

BA Df 356 

BA Dg 118 

BA Dg 119 

20.09 

– 

12.14 

30.25 

8.56 

7.95 

– 

10.42 

22.37 

2.28 

14.64 

– 

2.90 

7.58 

9.22 

1.24 

– 

2.84 

1.81 

1.41 

22.79 

– 

11.03 

42.49 

8.87 

7.17 

– 

3.14 

24.80 

4.40 

<10 

– 

<10 

<10 

<10 

– 

6.08 

6.82 

6.66 

6.16 

6.64 

6.00 

6.35 

6.48 

6.13 

BA Dg 120 

BA Dg 120 R 

BA Ea 92 

BA Ea 96 

BA Ea 97 

12.56 

86.07 

88.69 

141.61 

140.75 

12.16 

39.59 

40.11 

37.81 

37.27 

3.17 

59.13 

53.95 

63.11 

67.07 

.34 

13.70 

14.20 

6.50 

4.84 

7.88 

58.46 

56.43 

258.74 

258.62 

11.57 

69.56 

70.38 

102.60 

109.64 

<10 

30,378 

30,196 

18.13 

23.35 

6.35 

6.67 

6.62 

6.91 

6.93 

6.20 

6.70 

6.69 

6.90 

6.98 

BA Eb 292 

BA Eg 259 

BA Eg 259 R 

BA Fb 82 

BA Fb 82 R 

78.98 

13.41 

26.40 

4.60 

8.79 

21.89 

20.70 

5.92 

1.22 

8.64 

43.82 

10.25 

12.06 

3.21 

11.83 

3.69 

.86 

1.31 

.42 

1.86 

257.97 

12.83 

43.66 

5.31 

27.70 

2.16 

47.33 

5.89 

E .22 

.81 

<10 

<10 

<10 

<10 

11.47 

5.48 

6.16 

5.70 

6.05 

7.84 

5.47 

5.80 

5.94 

5.47 

6.36 

HA Ac 57 

HA Ac 58 

HA Ac 59 

HA Ad 16 

HA Ba 88 

9.97 

5.33 

2.56 

3.07 

3.04 

7.56 

3.77 

5.62 

2.36 

2.35 

8.56 

101.20 

2.76 

4.55 

4.55 

2.82 

2.05 

1.51 

.80 

.79 

22.44 

64.91 

8.96 

10.82 

11.18 

4.53 

.42 

< .31 

.83 

.79 

<10 

<10 

<10 

<10 

<10 

5.91 

6.88 

5.07 

5.90 

5.73 

5.95 

6.65 

4.80 

5.96 

6.01 

HA Bb 105 

HA Bb 106 

HA Bb 107 

HA Bc 34 

HA Bc 34 R 

Appendix 35 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Local 

well 

number 

Date 

sampled 

Length of 

open hole 

(feet) 

Acid-neutralizing capacity, 

bicarbonate, 

field (mg/L 

as CaCO3) 

Nitrogen 

ammonia, 

dissolved 

(mg/L as N) 

Nitrite, 

dissolved 

(mg/L as N) 

Nitrogen, 

ammonia plus 

organic, 

dissolved 

(mg/L as N) 

Phosphorus, 

dissolved 

(mg/L as P) 

Phosphorus, 

total 

(mg/L as P) 

HA Bc 35 

HA Bd 82 

HA Bd 87 

HA Bd 88 

HA Be 40 

10/23/2000 

07/31/2000 

10/11/2000 

10/17/2000 

10/24/2000 

425 

9 

157 

0 

200 

50 

98 

59.8 

106.1 

141.5 

<0.04 

< .02 

< .04 

< .04 

< .04 

<0.01 

< .01 

< .01 

< .01 

< .01 

E 0.08 

< .10 

E .09 

< .10 

E .06 

0.03 

< .01 

.03 

< .01 

.02 

0.04 

< .01 

.04 

E .00 

.02 

HA Bf 19 

HA Bf 20 

HA Ca 29 

HA Cb 286 

HA Cb 287 

09/06/2000 

09/06/2000 

09/07/2000 

07/12/2000 

08/01/2000 

180 

381 

60 

87 

508 

63 

123

20 

50 

146 

< .02 

.05 

< .02 

< .02 

< .02 

< .01 

< .01 

< .01 

< .01 

< .01 

<

<

< 

<

<

 .10 

.10 

.10 

.10 

.10 

< .01 

< .01 

.04 

< .01 

< .01 

<

<

<

 .01 

.01 

.04 

.01 

.01 

HA Cb 288 

HA Cb 289 

HA Cb 290 

HA Cc 196 

08/08/2000 

08/23/2000 

10/23/2000 

06/19/2000 

149 

222 

146 

87 

33 

34 

18.3 

132 

< .02 

.05 

< .04 

< .02 

< .01 

< .01 

< .01 

< .01 

<

E 

E 

< 

.10 

.08 

.07 

.10 

.01 

.04 

.01 

.03 

.03 

.04 

.02 

.03 

HA Cc 197 

HA Cc 197 R 

HA Cc 198 

HA Cc 199 

HA Cc 200 

07/11/2000 

07/11/2000 

07/24/2000 

08/22/2000 

09/07/2000 

189 

189 

34 

183 

270 

– 

– 

253 

222 

15 

< .02 

< .02 

< .02 

< .02 

< .02 

< .01 

< .01 

< .01 

< .01 

< .01 

< 

<

< 

E 

< 

.10 

.10 

.10 

.05 

.10 

.03 

.03 

.01 

.04 

E .01 E

.03 

.03 

.01 

.04 

.01 

HA Cc 201 

HA Cd 199 

HA Cd 200 

HA Cd 201 

HA Cd 201 R 

10/18/2000 

07/13/2000 

07/17/2000 

07/25/2000 

07/25/2000 

130 

155 

120 

103 

130 

42.1 

27 

17 

24 

– 

< .04 

< .02 

< .02 

< .02 

< .02 

< .01 

.04 

< .01 

< .01 

< .01 

< 

< 

<

<

<

.10 

.10 

.10 

.10 

.10 

.06 

< .01 

.04 

.02 

.02 

.07 

1.05 

.05 

.01 

.01 

HA Ce 119 

HA Ce 120 

HA Cf 171 

HA Cf 176 

HA Cf 176 R 

08/23/2000 

09/18/2000 

07/20/2000 

08/03/2000 

08/03/2000 

15 

82 

32 

10 

10 

66 

55 

37 

38 

– 

< .02 

.08 

< .02 

< .02 

< .02 

< .01 

< .01 

< .01 

< .01 

< .01 

E 

E

<

E 

E

.05 

.05 

.10 

.08 

.06 

.02 

.02 

< .01 

.01 

.01 

<

E

.02 

.02 

.01 

.01 

.01 

36 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through November 2000—Continued

pH pH 

whole water, whole water, 

Calcium, Magnesium, Sodium, Potassium, Chloride, Sulfate, Iron, Denver Wisconsin 

dissolved dissolved dissolved dissolved dissolved dissolved dissolved laboratory laboratory Local 

(mg/L (mg/L (mg/L (mg/L (mg/L (mg/L (mg/L (standard (standard well 

as Ca) as Mg) as Na) as K) as Cl) as SO4) as Fe) units) units) number 

– – – – – – – 5.82 5.96 HA Bc 35 

14.38 18.81 2.65 0.29 28.55 6.40 <10 6.55 7.00 HA Bd 82 

11.71 6.48 5.58 .65 10.22 1.28 <10 6.67 6.34 HA Bd 87 

27.20 17.98 12.01 .34 42.07 7.52 20.49 6.56 6.45 HA Bd 88 

18.55 23.45 4.62 .54 12.36 16.95 <10 6.77 7.11 HA Be 40 

21.42 2.06 5.55 1.46 3.11 8.98 <10 7.61 6.61 HA Bf 19 

21.12 8.77 18.69 .71 3.56 22.36 <10 5.81 5.61 HA Bf 20 

16.37 9.00 49.54 3.02 106.81 5.06 E 7.0 6.86 7.35 HA Ca 29 

7.06 4.51 6.54 3.12 6.41 10.66 417.18 6.22 6.59 HA Cb 286 

59.96 23.01 35.99 6.58 159.12 10.64 <10 5.96 6.08 HA Cb 287 

20.13 10.21 14.42 3.84 59.55 3.28 <10 5.91 5.60 HA Cb 288 

28.24 13.44 45.26 4.83 133.27 8.42 E 8.42 5.40 5.36 HA Cb 289 

– – – – – – – – – HA Cb 290 

29.88 15.90 6.43 .52 23.89 15.27 <10 6.61 7.22 HA Cc 196 

24.54 17.98 3.96 .98 28.53 7.64 <10 6.83 6.59 HA Cc 197 

24.17 17.76 3.91 .98 28.12 7.69 <10 6.74 6.59 HA Cc 197 R 

27.90 153.30 27.24 .82 392.81 24.97 <10 7.68 7.51 HA Cc 198 

46.09 26.54 26.33 E .19 45.07 32.45 <10 6.89 – HA Cc 199 

5.39 4.88 20.09 1.77 50.99 4.10 40.6 5.63 – HA Cc 200 

13.43 7.27 14.05 1.58 15.32 21.89 <10 6.06 5.97 HA Cc 201 

8.78 8.47 8.33 3.13 41.68 1.81 244.57 6.03 5.82 HA Cd 199 

16.59 2.96 18.97 .70 52.31 .45 56.06 6.20 5.94 HA Cd 200 

30.17 19.76 30.96 2.82 133.07 5.57 E 5.03 5.80 5.68 HA Cd 201 

30.11 19.72 30.78 2.85 134.03 5.58 <10 5.83 5.68 HA Cd 201 R 

49.69 23.64 11.60 .71 112.33 14.44 E 6.90 6.39 5.61 HA Ce 119 

16.64 8.23 5.26 .47 11.45 2.22 13.31 6.59 6.51 HA Ce 120 

5.55 2.01 6.32 .75 4.95 2.64 221.72 6.43 6.64 HA Cf 171 

8.38 4.73 10.71 1.01 17.09 3.95 <10 5.86 6.35 HA Cf 176 

8.49 4.81 10.79 1.02 16.86 3.95 <10 5.87 6.35 HA Cf 176 R 

Appendix 37 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in 

Baltimore and Harford Counties, Maryland, April through November 2000—Continued 

Local 

well 

number 

Date 

sampled 

Length of 

open hole 

(feet) 

Acid-neutralizing capacity, 

bicarbonate, 

field (mg/L 

as CaCO3) 

Nitrogen 

ammonia, 

dissolved 

(mg/L as N) 

Nitrite, 

dissolved 

(mg/L as N) 

Nitrogen, 

ammonia plus 

organic, 

dissolved 

(mg/L as N) 

Phosphorus, 

dissolved 

(mg/L as P) 

Phosphorus, 

total 

(mg/L as P) 

HA Cf 178 

HA Dc 121 

HA Dc 122 

HA Dc 122 R 

08/28/2000 

05/24/2000 

06/26/2000 

06/26/2000 

45 

140 

72 

72 

12 

56 

32 

– 

<0.02 

< .02 

< .02 

< .02 

<0.01 

< .01 

< .01 

< .01 

<0.10 

< .10 

< .10 

< .10 

E 0.00 

.03 

.03 

.03 

E 0 .01 

.03 

.04 

.03 

HA Dc 123 08/01/2000 120 98 < .02 < .01 < .10 .01 .01 

HA Dc 124 

HA Dd 108 

HA De 297 

HA De 297 R 

10/16/2000 

05/02/2000 

05/31/2000 

05/31/2000 

260 

244 

181 

181 

129.3 

146 

174 

– 

E .03 

.07 

.02 

– 

.01 

< .01 

< .01 

– 

< .10 

E .06 

< .10 

– 

< .01 

.02 

.01 

– 

E .00 

.02 

E .01 

– 

HA De 298 

HA De 299 

HA De 300 

06/20/2000 

07/18/2000 

10/11/2000 

140 

328 

7 

153 

134 

6.7 

< .02 

< .02 

< .04 

< .01 

< .01 

< .01 

< .10 

< .10 

< .10 

.02 

< .01 

< .01 

.82 

< .01 

< .01 

38 Microbiological Contamination and Enteric Viruses in Baltimore and Harford Counties, MD 
Appendix. Microbiological and water-quality data for 91 public water-supply wells in

Baltimore and Harford Counties, Maryland, April through November 2000—Continued

pH pH 

whole water, whole water, 

Calcium, Magnesium, Sodium, Potassium, Chloride, Sulfate, Iron, Denver Wisconsin 

dissolved dissolved dissolved dissolved dissolved dissolved dissolved laboratory laboratory Local 

(mg/L (mg/L (mg/L (mg/L (mg/L (mg/L (mg/L (standard (standard well 

as Ca) as Mg) as Na) as K) as Cl) as SO4) as Fe) units) units) number 

8.50 3.92 7.27 0.53 2.37 E 0.17 <10 5.99 5.80 HA Cf 178 

18.99 6.55 8.59 .73 6.86 18.49 E 5.13 6.45 6.49 HA Dc 121 

8.83 3.81 5.08 .79 5.20 1.49 <10 6.85 6.18 HA Dc 122 

9.15 3.94 5.31 .86 5.17 1.42 <10 7.15 6.24 HA Dc 122 R 

51.95 21.37 9.00 .75 111.98 .70 <10 6.51 7.04 HA Dc 123 

22.31 11.76 6.63 1.45 7.12 11.88 3,619.90 6.88 6.89 HA Dc 124 

17.94 2.29 32.18 3.64 1.51 6.54 16.40 7.93 7.90 HA Dd 108 

32.25	 19.58 11.34 2.55 32.12 2.74 157.65 – 7.66 HA De 297 

– – – – – – – 7.64 7.64 HA De 297 R 

22.12 10.05 12.41 2.19 4.78 9.98 896.32 6.97 7.20 HA De 298 

21.29 11.76 5.74 1.57 4.59 3.21 610.99 7.49 7.30 HA De 299 

.83 .33 2.19 0.43 2.20 1.70 18.63 5.97 5.45 HA De 300 

Appendix 39