INDICATORS OF THE SOURCES AND 

DISTRIBUTION OF NITRATE IN WATER 

FROM SHALLOW DOMESTIC WELLS IN 

AGRICULTURAL AREAS OF THE NEW 

JERSEY COASTAL PLAIN

by E.F. Vomnkel and R.J. Tapper

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 93-4178

Prepared in cooperation with the

NEW JERSEY DEPARTMENT OF ENVIRONMENTAL PROTECTION 

AND ENERGY

West Trenton, New Jersey 

1995
U.S. DEPARTMENT OF THE INTERIOR 

Bruce Babbitt, Secretary

U.S. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director

For additional information write to:

District Chief

U.S. Geological Survey

Mountain View Office Park

810 Bear Tavern Road

Suite 206

West Trenton, New Jersey 08628

Copies of this report can be purchased from:

U.S. Geological Survey 

Earth Science Information Center 

Open-File Reports Section 

Box 25286, MS 517 

Denver Federal Center 

Denver, CO 80225
CONTENTS

Page

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

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

Purpose and scope ........................................................... 2

Previous investigations........................................................ 2

Acknowledgments ........................................................... 3

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

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

Agricultural land use and sources of nitrate........................................ 6

Methods of data collection and analysis .................................................. 8

Well-selection criteria.......................................................... 8

Water-quality sampling, chemical analyses, and quality control......................... 8

Quantification of land use near a well ............................................ 12

Statistical methods ........................................................... 12

Indicators of the sources and distribution of nitrate in water from shallow domestic wells.......... 13

Factors affecting or related to nitrate concentrations................................. 13

Sampling event ....................................................... 13

Hydrogeologic characteristics............................................ 15

Aquifer system................................................. 15

Hydrogeologic scenario .......................................... 17

Well-construction characteristics.......................................... 17

Type of well................................................... 17

Well depth..................................................... 19

Other water-quality characteristics and constituents........................... 19

Specific conductance ............................................ 22

Dissolved oxygen............................................... 22

Stable isotopes of nitrogen........................................ 25

Pesticides ..................................................... 25

Land-use activities..................................................... 27

Presence of livestock ............................................ 27

Distance of the wellhead from the septic system....................... 27

Predominant land use surrounding the wellhead ....................... 31

Multivariate statistical model to predict nitrate concentrations ......................... 31

Summary and conclusions............................................................ 34

References cited.................................................................... 37

Appendix 1: Well-construction characteristics of 12 domestic wells in agricultural

areas of the New Jersey Coastal Plaia ............................................... 40

Appendix 2: Results of water-quality analyses of samples from 12 domestic wells in

agricultural areas of the New Jersey Coastal Plain...................................... 41

A. Physical characteristics and chemical constituents measured in the field .............. 41

B. Dissolved major ions....................................................... 42

C. Dissolved trace elements.................................................... 43

D. Dissolved nutrients and nitrogen isotope ratios .................................. 44

E. Dissolved organic carbon, methylene blue active substances, fecal

coliform, and fecal streptococci ............................................ 45

F. Total triazine and acetanilide herbicides ........................................ 46

G. Total carbamate insecticides................................................. 47

H. Volatile organic compounds ................................................. 48

iii
CONTENTS

Page

ILLUSTRATIONS

Figure 1. Map showing the location of the study areas, agricultural land, and generalized

hydrogeologic section A-A' .............................................. 4

2. Generalized hydrogeologic section A-A' through the New Jersey Coastal Plain ....... 5

3. Generalized ground-water-flow patterns and concentrations of nitrate in agricultural

areas ................................................................ 5

4. Histogram showing the percentage of New Jersey land that was agricultural, 1900-

1990 ................................................................ 7

5. Maps showing locations of wells used to evaluate (A) the regional effects of land use 

on shallow-ground-water quality in the New Jersey Coastal Plain, (B) the local 

effects of agriculture on shallow ground-water quality in the outcrop area of the 

Kirkwood-Cohansey aquifer system, and (C) the local effects of agriculture on 

shallow ground-water quality in the outcrop area of the Potomac-Raritan-Magothy 

aquifer system......................................................... 9

6. Scatterplot showing the distribution of concentrations of nitrate in water from 12 

shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, by 

sampling event....................................................... 15

7. Boxplots showing the distributions of concentrations of nitrate in water from 12 

shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, by 

location of the well relative to the surface-water divide ....................... 18

8. Boxplots showing the distributions of concentrations of nitrate in shallow ground 

water in predominantly agricultural areas of the New Jersey Coastal Plain, by type 

of well.............................................................. 20

9. Boxplots showing the distributions of the depths to the top of the screened interval of 

12 shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, 

relative to the maximum contaminant level for nitrate ........................ 21

10. Boxplots showing the distributions of values of specific conductance of water from 12 

shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, 

relative to the maximum contaminant level for nitrate ........................ 23

11. Boxplots showing the distributions of concentrations of dissolved oxygen in water 

from 12 shallow domestic wells in agricultural areas of the New Jersey Coastal 

Plain, relative to the maximum contaminant level for nitrate ................... 24

12. Boxplots showing the distributions of values of 8 N15 in water from 12 shallow 

domestic wells in agricultural areas of the New Jersey Coastal Plain, relative to the 

maximum contaminant level for nitrate.................................... 26

13. Boxplots showing the distributions of concentrations of nitrate in water from 12 

shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, 

relative to the presence of pesticides in the water samples ..................... 28

14. Boxplots showing the distributions of concentrations of nitrate in water from 12 

shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, 

relative to the presence of livestock near the wellhead ........................ 29

iv
ILLUSTRATIONS-Continued

Page

Figure 15. Boxplots showing the distributions of distances between the wellhead and the septic 

system for 12 shallow domestic wells in agricultural areas of the New Jersey 

Coastal Plain, relative to the maximum contaminant level for nitrate............. 30

16. Boxplots showing the distributions of concentrations of nitrate in shallow ground 

water in predominantly agricultural areas of the New Jersey Coastal Plain, by 

aquifer system........................................................ 32

17. Scatterplot showing the relation between concentrations of nitrate in water from 

shallow domestic wells and the percentage of agricultural land within 800-meterradius buffer zones of the wellhead ....................................... 33

TABLES

Table 1. Number of livestock, dairy, and poultry raised on New Jersey farms............ 7

2. Physical characteristics and chemical constituents measured in the field and

determined in the laboratory in water samples during each sampling event..... 11

3. Physical characteristics and chemical constituents measured in the field and 

concentrations of water-quality constituents for 12 shallow domestic wells in 

agricultural areas of the New Jersey Coastal Plain, by sampling event......... 14

4. Physical characteristics and chemical constituents measured in the field and 

concentrations of water-quality constituents for 12 shallow domestic wells in 

agricultural areas of the New Jersey Coastal Plain, by aquifer system......... 16

5. Statistical summary of the concentrations of nitrate in water from 12 shallow 

domestic wells in agricultural areas of the New Jersey Coastal Plain, by 

location of the well relative to the surface-water divide .................... 18

6. Statistical summary of the concentrations of nitrate in shallow ground water in 

predominantly agricultural areas of the New Jersey Coastal Plain, by type of 

well............................................................. 20

7. Statistical summary of the depths to the top of the screened interval for 12 shallow 

domestic wells in agricultural areas of the New Jersey Coastal Plain, relative 

to the maximum contaminant level for nitrate............................ 21

8. Statistical summary of values of specific conductance of water from 12 shallow 

domestic wells in agricultural areas of the New Jersey Coastal Plain, relative 

to the maximum contaminant level for nitrate............................ 23

9. Statistical summary of concentration of dissolved oxygen in water from 12 

shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, 

relative to the maximum contaminant level for nitrate ..................... 24

10. Statistical summary of values of 8 N15 in water from 12 shallow domestic wells 

in agricultural areas of the New Jersey Coastal Plain, relative to the maximum 

contaminant level for nitrate ......................................... 26

11. Statistical summary of concentrations of nitrate in water from 12 shallow

domestic wells in agricultural areas of the New Jersey Coastal Plain, by the 

presence of pesticides in the water samples.............................. 28
TABLES-Continued

Page

Table 12. Statistical summary of the distributions of concentrations of nitrate in water from 

12 shallow domestic wells in agricultural areas of the New Jersey Coastal 

Plain, by the presence of livestock near the wellhead...................... 29

13. Statistical summary of the distances between the wellhead and the septic system 

for 12 shallow domestic wells in agricultural areas of the New Jersey Coastal 

Plain, relative to the maximum contaminant level for nitrate ................ 30

14. Statistical summary of concentrations of nitrate in shallow ground water in the

New Jersey Coastal Plain, by predominant land use....................... 32

15. Mean ratio of concentrations of dissolved-nitrogen species to concentrations of all 

dissolved nitrogen in water from shallow wells in predominantly agricultural 

areas of the New Jersey Coastal Plain, in the regional data set............... 33

16. Capability of single variables to predict the relation of the concentration of nitrate 

in water from 12 shallow domestic wells in agricultural areas of the New Jersey 

Coastal Plain to the maximum contaminant level for nitrate................. 35

17. Capability of multiple variables to predict the relation of the concentration of 

nitrate in water from 12 shallow domestic wells in agricultural areas of the 

New Jersey Coastal Plain to the maximum contaminant level for nitrate....... 36
CONVERSION FACTORS, VERTICAL DATUM, 

AND ABBREVIATED WATER-QUALITY UNITS

Multiply Bv To obtain

centimeter (cm) 0.3937 inch 

meter (m) .3048 foot 

kilometer (km) .6214 mile 

meter per kilometer 

cubic meter per day (m3/d) 264.2 gallon per day

hectare (ha) 2.471 acre 

square kilometer (km 2) .3861 square mile

kilogram (kg) 2.205 pound

liter (L) .2642 gallon

metric ton 1.1016 ton

degree Celsius (°C) 1.8 x °C + 32 degree Fahrenheit

mg/L = milligram per liter

ug/L = microgram per liter

meq/L = millequivalents per liter

(iS/cm = microsiemens per centimeter at 25 °C

°/00 = P^ mil

col/100 mL = colonies per 100 milliliters

Sea level: 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.
Indicators of the Sources and Distribution of Nitrate in Water from 

Shallow Domestic Wells in Agricultural Areas of the New Jersey

Coastal Plain

byE.F. Vowinkel and R.J. Tapper

ABSTRACT

Previously collected and new water-quality data from shallow wells (screened interval less than 30 

meters below the land surface) in predominantly agricultural areas of the New Jersey Coastal Plain were 

used to determine the relation of nitrate concentrations in shallow ground water to various hydrogeologic 

and land-use factors in the study area. Information on land use, well construction, hydrogeology, and water 

quality were used to predict the conditions under which concentrations of nitrate as nitrogen in water from 

domestic wells in predominantly agricultural areas are most likely to be equal to or larger than the U.S. 

Environmental Protection Agency maximum contaminant level (MCL) of 10 milligrams per liter.

Results of the analyses of water-quality samples collected during 1980-89 from 230 shallow wells in 

the outcrop areas of the Kirkwood-Cohansey and Potomac-Raritan-Magothy aquifer systems were used to 

evaluate the regional effects of land use on shallow-ground-water quality. Results of statistical analysis 

indicate that concentrations of nitrate in shallow ground water are significantly different (p = 0.001) in 

agricultural areas than in undeveloped areas in both aquifer systems. Concentrations of nitrate nitrogen 

exceeded the MCL in water from more than 33 percent of the 60 shallow wells in agricultural areas. 

Concentrations of nitrate in water from shallow wells in agricultural areas increased as the percentage of 

agricultural land within an 800-meter-radius buffer zone of the wellhead increased (r = 0.81). 

Concentrations of nitrate in water from domestic wells in agricultural areas were similar (p = 0.23) to those 

concentrations in water from irrigation wells. These results indicate that most of the nitrate in water from 

domestic wells in agricultural areas results from agricultural practices rather than other sources, such as 

septic systems.

Water-quality samples collected from 12 shallow domestic wells in agricultural areas screened in the 

outcrop areas of the Kirkwood-Cohansey and Potomac-Raritan-Magothy aquifer systems were used to 

evaluate the local effects of hydrogeologic conditions and land-use activities on shallow-ground-water 

quality. Concentrations of water-quality constituents in these wells were similar among four sampling 

events over a 1-year span. The concentration of nitrate in water from 6 of the 12 wells exceeded the MCL. 

Concentrations of nitrate greater than the MCL are associated with: values of specific conductance greater 

than 200 microsiemens per centimeter at 25 degrees Celsius, a screened interval whose top is less than 20 

meters below land surface, concentrations of dissolved oxygen greater than 6 milligrams per liter, presence 

of pesticides in the ground water, a distance of less than 250 meters between the wellhead and the surfacewater divide, and presence of livestock near the wellhead. Ratios of stable isotopes of nitrogen in the water 

samples indicate that the source of nitrate in the ground water was predominantly chemical fertilizers 

rather than livestock wastes or effluent from septic systems.

INTRODUCTION

Contamination of ground water by agricultural chemicals, especially nitrates, is a major concern of 

environmental and regulatory agencies throughout the nation. Nitrate is soluble in water and is transported 

from its source along local and regional ground-water flow paths. Although nitrate is relatively nontoxic, in 

the intestines of infants it can be reduced by bacteria to nitrite and may result in the disease 

methemoglobinemia. Infant mortality from this disease is rare where concentrations of nitrate as nitrogen
(as N) in drinking water are less than 10 mg/L; however, the incidence of mortality increases with 

increasing concentration (Walton, 1951). The U.S. Environmental Protection Agency (USEPA) has set a 

maximum contaminant level (MCL) of 10 mg/L for nitrate (as N) in water (U.S. Environmental Protection 

Agency, 1991). An MCL is the maximum permissible level of a contaminant in water that is delivered to 

any user of a public water system.

As a result of earlier studies that showed that concentrations of nitrate in ground water in agricultural 

areas commonly exceeded the MCL, a project was initiated by the U.S. Geological Survey (USGS) in 

cooperation with the New Jersey Department of Environmental Protection and Energy (NJDEPE) as part 

of the New Jersey Safe Drinking Water Program.

Purpose and Scope

The purpose of this report is to (1) document the seasonal variability of ground-water-quality 

constituents in shallow domestic wells in agricultural areas of the Coastal Plain of New Jersey; (2) describe 

the use of hydrogeologic, land-use, well-construction, and water-quality characteristics and constituents as 

indicators to predict whether the concentration of nitrate in water from a shallow domestic well in those 

areas will exceed the MCL; and (3) identify the predominant source(s) of nitrate in water from shallow 

domestic wells in agricultural areas.

Previous Investigations

In 1984, as part of its Toxic Substances Hydrology Program, the USGS began to evaluate the 

degradation of ground-water quality as a result of human activities. These studies were designed to test 

statistically the hypothesis that shallow-ground-water quality is related to human activities expressed as 

land use (Helsel and Ragone, 1984). Preliminary results from study areas in New York, New Jersey, 

Connecticut, Florida, Nebraska, and Colorado indicate that regional ground-water quality has been 

affected by human activities (Cain and others, 1989, p. 230).

The relation between nitrate in shallow ground water and land use in the outcrop area of the 

Potomac-Raritan-Magothy aquifer system in the New Jersey Coastal Plain was assessed by Barton and 

others (1987) and Kish and others (1988). Louis and \fowinkel (1989) evaluated the presence of 

agricultural chemicals in ground water in the outcrop areas of the Potomac-Raritan-Magothy aquifer 

system and the Kirkwood-Cohansey aquifer systems. Vowinkel (1991) reported that the relation between 

land use and nitrate in shallow ground water was similar between the two Coastal Plain aquifer systems; 

concentrations of nitrate in shallow ground water were significantly different in agricultural areas than in 

undeveloped areas. Water from more than 33 percent of the shallow wells in predominantly agricultural 

areas contained concentrations of nitrate exceeding the MCL.

Results of the USEPA's National Pesticide Survey indicate that concentrations of nitrate in ground 

water were equal to or greater than the MCL in 1.2 percent of the community and 2.4 percent of the rural 

wells nationwide. A statistical analysis of the USEPA data indicated that well depth was the only consistent 

predictor of nitrate concentration in ground water in community and rural wells (U.S. Environmental 

Protection Agency, 1992); however, because the hydrogeologic variables used in the model, such as the 

presence of confining units, were determined at the county scale rather than at a site or hydrogeologic-unit 

scale, the results of this study were limited. The USEPA findings indicate that further stratification of the 

data is needed to accurately test hypotheses concerning the associations among variables.

Results of a study conducted in Mercer and Burlington Counties, New Jersey (Murphy, 1992) 

demonstrated that the concentrations of nitrate in water from shallow drinking-water wells (screened 

intervals less than 30 m below the land surface) were significantly different in agricultural and residential 

areas than in woodland areas. Concentrations of nitrate in shallow ground water were significantly 

different in wells less than 15m from a septic system than in wells farther than 15m from a septic system; 

this result indicates that effluent from septic systems may have a significant effect on nitrate concentrations 

in water from sampled wells.
Acknowledgments

The authors thank the homeowners and farmers who allowed access to their wells for collection of 

water samples. Their cooperation is greatly appreciated.

DESCRIPTION OF THE STUDY AREA

The Coastal Plain physiographic province covers about 10,900 km2 in southern New Jersey (fig. 1). 

The study area consists of a variety of hydrogeologic and land-use settings that can affect ground-water 

quality.

Hydrooeologic Setting

The Coastal Plain is underlain by a seaward-dipping wedge of unconsolidated sediments consisting 

of alternating layers of sand, silt, and clay of Cretaceous to Holocene age (fig. 2). The hydrogeologic 

framework of (Zapecza, 1989) and regional ground-water flow in (Martin, 1990) the New Jersey part of the 

Coastal Plain are well-documented. The Coastal Plain is separated from other physiographic provinces in 

New Jersey by the Fall Line, which extends from Raritan Bay in the northeast to Delaware Bay in the 

southwest. Two major aquifers, the Potomac-Raritan-Magothy aquifer system and the KirkwoodCohansey aquifer system, supply more than 90 percent of the freshwater used by the 3.2 million people 

living on the Coastal Plain in New Jersey. The Potomac-Raritan-Magothy aquifer system in the Cretaceous 

Potomac-Group, Raritan-Formation, and Magothy Formation underlies the entire Coastal Plain but crops 

out in a narrow 5- to 16-km-wide strip of land that comprises about 1,000 km2 and extends from Raritan 

Bay to Delaware Bay. The outcrop area of the Kirkwood-Cohansey aquifer system in the Miocene 

Kirkwood Formation and the Cohansey Sand exceeds 7,500 km2.

Hydrogeologic conditions in the Coastal Plain are such that shallow ground water is vulnerable to 

contamination from point and nonpoint sources. The land surface generally is flat; relief rarely is greater 

than 30 m in a drainage basin. Agricultural areas typically are in the upland parts of the drainage basin, 

where the soils are well-drained. Soils in agricultural areas in the northern part of the outcrop area of the 

Potomac-Raritan-Magothy aquifer system consist predominantly of sandy loam. In the outcrop area of the 

Kirkwood-Cohansey aquifer system, soils in agricultural areas consist mostly of gravelly sandy loam and 

loamy sand (Tedrow, 1986, pi. 1). Sandy loam- and loamy sand-type soils generally contain only small 

amounts of organic matter, which limits the ability of the soils to impede the movement of agricultural 

chemicals from the unsaturated zone to the water table.

The primary source of recharge to the aquifers in the Coastal Plain is precipitation. A long-term 

water budget under unstressed conditions consists of about 112 cm/yr of precipitation, 51 cm/yr of 

streamflow, and 61 cm/yr of evapotranspiration (Vowinkel and Foster, 1981, p. 1). Most of the ground 

water is discharged to surface-water bodies and only a small amount infiltrates through confining units to 

recharge the underlying confined aquifers (Martin, 1990, p. 45). The authors estimated from available 

water-level data that the median depth to the water table is about 5.8 m in the outcrop area of the PotomacRaritan Magothy aquifer system and 3.7 m in the outcrop area of the Kirkwood-Cohansey aquifer system. 

The horizontal hydraulic conductivity of the unconsolidated sediments comprising the aquifer systems 

commonly is between 40 and 60 m/d (Martin, 1990, p. 10-12).

Shallow ground water in the Coastal Plain generally flows from upland recharge areas toward 

discharge areas along streams and wetlands (fig. 3). The locations of the ground-water and surface-water 

divides typically coincide. The direction of ground-water flow is predominantly downward near the 

ground-water divide, horizontal in the center of a drainage basin, and nearly vertically upward at the 

discharge area. In areas unstressed by ground-water withdrawals for irrigation, the water typically is older 

in deeper parts of the aquifer system downgradient from the ground-water divide than in shallower parts of
EXPLANATION

Agricultural land (Source: Fegas 

and others, 1983)

- Extent of the outcrop area of the 

Kirkwood Formation (from U.S. 41< 

Geological Survey, 1967)

- Extent of the outcrop area of the 

Potomac Group and Raritan 

and Magothy Formations (from 

U.S. Geological Survey, 1967)

, Line of generalized hydrogeologic 

' section shown in figure 2

NEW YORK

74°

10 20 30 MILES

HII I

0 10 20 30 KILOMETERS

Delaware 

Bay

39

Figure 1. Location of the study areas, agricultural land, and generalized hydrogeologic 

section A-A?.
p||g COMPOSITE CONFINING LAYER 

'^-^ AND MINOR AQUIFER

See figure 1 for trace of section

SEA 

LEVEL

NOT TO SCALE

Figure 2. Generalized hydrogeologic section A-A1 through the New Jersey Coastal Plain. 

(Modified from Eckel and Walker, 1986, p. 10.)

Woodland and 

residential Farm field

Wooded area 

along stream

EXPLANATION

CONCENTRATION OF NITRATE

^H Significant nitrate levels

Minimal or no nitrate

Direction of groundwater flow

1 to 5 kilometers -

Figure 3. Generalized ground-water-flow patterns and concentrations of nitrate in agricultural 

areas. (Modified from Hamilton and Shedlock, 1992, p.5.)
the aquifer system near the divide. Concentrations of nitrate in ground water would be expected to 

decrease as the water flows downward and toward a stream because the nitrate disperses along the flow 

path and may be reduced by denitrifying bacteria under anaerobic conditions. Furthermore, water typically 

is older near ground-water-discharge areas and may be too old to have been affected by human activities at 

the land surface.

Aqricuihjral Land Use and Sources of Nitrate

New Jersey is composed of a variety of land-use and land-cover types that can affect ground-water 

quality. Most of the Coastal Plain is undeveloped and the effects of human activities on ground-water 

quality in these areas are small. About 70 percent of the outcrop area of the Kirkwood-Cohansey aquifer 

system is pineland forests and wetlands and about 20 percent of the outcrop area of the Potomac-RaritanMagothy aquifer system is undeveloped land. Urban land (residential and nonresidential) areas in the 

Coastal Plain are mostly near the Delaware and Raritan Rivers and along the Atlantic Coast.

The amount of agricultural land in New Jersey (fig. 1) has been declining steadily since the turn of 

the century. In 1900, almost 60 percent of the land in New Jersey was agricultural, compared to about 22 

percent in the early 1970's (fig. 4), and 18 percent in 1990 (New Jersey Department of Agriculture, 1990). 

Although the amount of land used for agriculture has been declining, agriculture remains a large part of the 

State's economy. Most of the agricultural land is cropland with smaller amounts of pasture, animal 

feedlots, nurseries, and orchards. The crops grown are diverse; 77 types of vegetables, 10 types of fruits, 

and 8 grain commodities are grown in New Jersey (Louis and others, 1989). New Jersey ranks in the top 

five States in the country in the production of snap beans, cabbage, cranberries, and peaches (New Jersey 

Department of Agriculture, 1990), most of which are grown in the Coastal Plain. Other important crops in 

this region include soybeans, hay, wheat, barley, potatoes, sweetcom, peppers, tomatoes, blueberries, 

strawberries, nursery crops, and fruit trees.

Agricultural land comprises nearly 20 percent of the outcrop areas of the Kirkwood-Cohansey and 

the Potomac-Raritan-Magothy aquifer systems. Possible sources of nonpoint contamination in agricultural 

areas include fertilizers used for plant production, pesticides used to control weeds and insects, animal 

wastes from feedlots, and effluent from septic systems and underground storage tanks.

Fertilizers are applied to agricultural land to increase plant productivity. In 1989, sales of about 

224,000 metric tons of fertilizer were reported to the New Jersey Agricultural Statistics Service; 145,000 

metric tons were for farm utilization and 79,000 metric tons were for nonfarm utilization. Nitrogen 

contained in mixed fertilizers was about 22,000 metric tons and sales of about 29,000 metric tons of 

chemical nitrogen materials were reported. Sales of about 14,000 metric tons of organic materials 

consisting of dried manure and sludge also were reported (New Jersey Department of Agriculture, 1990, 

p. 94).

Manures from livestock contain nitrogen that could potentially contaminate ground water. Generally, 

livestock production in New Jersey declined from 1960 to 1990 (table 1). Only the number of sheep and 

turkeys increased from 1970 to 1990. Because many types of livestock are raised in small, confined areas, 

problems commonly arise with the disposal of their wastes, runoff of manure into nearby surface-water 

bodies, and the leaching of nitrogen into ground water. The authors estimate that about 15,000 metric tons 

of nitrogen was produced in 1989 from beef, dairy, swine, and poultry wastes in New Jersey. The amount 

of nitrogen that leaches into ground water or surface water is not known, however.

Septic systems are the means of disposal of human wastes for about 18 percent of the population of 

New Jersey (Susan Lance, Rutgers University, written commun., 1992) and almost 100 percent of the 

population in agricultural areas of the New Jersey Coastal Plain. Nitrogen in septic-system effluent usually 

consists of about 75 to 80 percent ammonium and 20 to 25 percent organic nitrogen. Concentrations of 

total nitrogen in septic systems range from 25 to 100 mg/L. The typical annual nitrogen contribution from 

a family of four is estimated to be about 33 kg/yr (Hantzsche and Finnemore, 1992, p. 491). In 1987 there
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990

YEAR

Figure 4. Percentage of New Jersey land that was agricultural, 1900-1990. (Data from New Jersey 

Department of Agriculture, 1990, p. 93.).

Table 1. Number uf livestock, dairy, and poultry raised on New Jersey farms

[Modified from New Jersey Department of Agriculture, 1961, 1970, 1980, 1990]

Number of head x 1,000

Livestock

type

Cattle and calves

Milk cows

Hogs and pigs 

Sheep and lambs 

Chickens (layers) 

Turkeys

1960

200

140

172 

16 

12,596 

13

1970

132

69

121 

8 

4,547 

12

1979

108

41

45 

7 

1,483 

59

1989

75

28

30 

15 

1,687 

100
were about 9,000 farms in New Jersey. If the average farm household contains four persons, the annual 

load of total nitrogen from septic systems at these 9,000 farm homes is estimated to be about 300 metric 

tons. The estimated nitrogen load from septic systems is less than 1 percent of that reported for sales of 

fertilizers.

In almost all farming operations in New Jersey, both nutrients and pesticides are used to increase 

crop productivity. Pesticides are used to control weeds, insects, and fungi and as growth regulators. Almost 

10,000 formulated pesticide products containing 400 to 500 active ingredients are registered for use in 

New Jersey. Pesticides are used in most agricultural areas of the Coastal Plain. Farmers reported the 

application of about 859 metric tons of 176 different active ingredients on farming operations in New 

Jersey during 1985. The applied pesticides included 358 metric tons of fungicides, 266 metric tons of 

herbicides, 228 metric tons of insecticides, 6 metric tons of fumigants, and about 1 metric ton of growth 

regulators (Louis and others, 1989, p. 198). The greatest amount of herbicides applied were alachlor, 

metolachlor, and atrazine. The greatest amount of insecticides applied were parathion, oil, and methomyl. 

Sulfur was the most commonly used fungicide.

METHODS OF DATA COLLECTION AND ANALYSIS

Information on well-location, well-construction, hydrogeologic, water-quality, and land-use 

characteristics were collected and stored in a geographic information system (GIS). The GIS allows for the 

spatial referencing of the data. Two stratified data sets were developed to test hypotheses concerning the 

relations of shallow-ground-water quality to hydrogeologic, well-construction, and land-use variables.

Well-Selection Criteria

The first data set, which will be called the regional data set, was developed from available data to 

evaluate the relation between land use and shallow-ground-water quality at a regional scale. The regional 

data set consists of water-quality samples collected by the USGS during 1980-89 from 233 shallow wells 

screened in the outcrop areas of the Potomac-Raritan-Magothy aquifer system and the KirkwoodCohansey aquifer system. Well-selection criteria were established to reduce sampling biases associated 

with hydrogeologic conditions, well-construction characteristics, and spatial autocorrelation (\bwinkel 

and Battaglin, 1989; Barringer and others, 1990). Because water-quality observations from sites located 

near each other can be spatially autocorrelated and lack independence, only wells located within the 

outcrop area with screened intervals less than 30 m below land surface and a minimum well-separation 

distance of 1,600 m were included in the data set.

The second data set, which will be called the local data set, was developed to evaluate the effects of 

agricultural land use on the quality of water from shallow domestic wells at the local scale and to monitor 

seasonal variations in ground-water quality during about a 1-year span. Water samples were collected from 

12 shallow domestic wells between April 23,1991, and April 21, 1992. Six wells are screened in the 

outcrop area of the Potomac-Raritan-Magothy aquifer system (Study area 1) and six of the wells are 

screened in the outcrop area of the Kirkwood-Cohansey aquifer system (Study area 2) (fig. 5). The 

screened intervals of the 12 domestic wells were less than 30 m below the land surface and were located 

near (less than 250 m) or downgradient from a surface-water divide. Each house near the sampled 

domestic well was serviced by a septic system. Livestock were raised on four of the farms, within 400 m of 

the domestic well, but this was not a factor in the selection process.

Woter-QuaUtv Sampling. Chemical Analyses, and Qualftv Control

Water-quality samples were collected by using procedures described by Wood (1976) and Wershaw 

and others (1983). Wells were sampled at spigots near the wellhead prior to discharging into holding tanks. 

Before collecting a sample, a minimum of three casing volumes of water were evacuated from the well. 

Pumping continued until temperature, pH, specific conductance, and dissolved-oxygen concentration was 

stable for at least three consecutive measurements. After stabilization, an incremental field titration for
I I I 

0 10 20 30 KILOMETERS

Agricultural land (Source: Fegas 

and others, 1983)

 County boundary

Extent of the outcrop of the 

Kirkwood Formation (from 

U.S. Geological Survey, 1987)

 Extent of the outcrop of the 

Potomac Group and Raritan 

and Magothy Formation (from 

U.S. Geological Survey, 1987)

33-685. Location of well and well number

I 1 I 

0246 KILOMETERS

Figure 5. Locations of wells used to evaluate (A) the regional effects of land use on shallow-ground-water quality in the New Jersey Coastal Plain, (B) the local effects of agriculture on shallow ground-water quality in the outcrop area of the Kirkwood-Cohansey 

aquifer system, and (C) the local effects of agriculture on shallow ground-water quality in 

the outcrop area of the Potomac-Raritan-Magothy aquifer system.
alkalinity was performed and was followed by sample preparation, preservation, and analysis as described 

by Fishman and Friedman (1985) for dissolved and suspended inorganic constituents and by Wershaw and 

others (1983) for organic compounds. Major ion and nutrient samples were filtered in the field.

Minimum reporting levels of physical characteristics and chemical constituents measured in the field 

and constituents determined in the laboratory are listed in table 2. Results of the analyses are provided in 

appendix 2. All samples were refrigerated and all, except those to be analyzed for purgeable organic 

compounds, were mailed within 72 hours to the U.S. Geological Survey National Water Quality 

Laboratory (NWQL) in Arvada, Colorado. Samples collected for determination of purgeable organic 

compounds were analyzed at the USGS's New Jersey District laboratory by using a purge-and-trap gas 

chromatograph with a Hall detector in series with a photoionization detector (Kammer and Gibs, 1989). 

NWQL laboratory procedures are identified by Feltz and others (1984). Methods of sample preparation 

and methods of analysis for determination of dissolved and suspended inorganic constituents in and 

physical characteristics of water are documented by Fishman and Friedman (1985). Wershaw and others 

(1983) describe the procedures used for analyzing water samples for concentrations of organic carbon and 

pesticides.

A quality-assurance program was used to evaluate the accuracy of the water-quality data presented 

in this report. The internal quality-control program followed by the NWQL is documented by Friedman 

and Erdman (1982), Peart and Thomas (1983), and Wershaw and others (1983). The program involves 

analyzing a large percentage of samples to evaluate accuracy and precision. The NWQL also is checked by 

the USGS's Quality Assurance Program, under which standard samples are submitted for analysis and 

tabulated statistics on the results are reported.

The quality-assurance program developed for the local data set consisting of 12 wells included 

comparisons of values reported from field and laboratory measurements, cation and anion balance checks, 

replicate samples, field- and laboratory-blank samples, a spiked sample for pesticides, and comparison of 

analytical results among multiple laboratories. The median percent difference between cations and anions 

was less than 3 percent, and the percent difference did not exceed 8 percent in any sample. The median 

percent difference between measurements of pH and specific conductance made in the field and in the 

laboratory was less than 6 percent. Because pH and specific conductance can change during sample 

collection and analysis at the NWQL, field measurements are used exclusively in any statistical analyses.

Replicate samples from the local data set were collected from two wells and analytical results for all 

constituents were compared. Concentrations of inorganic constituents were similar between replicate 

samples, and pesticides were detected at similar concentrations in both samples. Duplicate samples were 

collected at 10 sites during the first sampling event and were submitted to two laboratories for analysis for 

concentrations of nitrate. One sample was sent to the NWQL and the second sample was sent to a 

laboratory at Heidelberg College in Tifton, Ohio, for analysis (Baker, 1990). The concentrations reported 

by the two laboratories were similar (r = 0.83).

Three samples containing deionized water were analyzed for triazine and acetanilide herbicides and 

carbamate insecticides. One sample was sent directly from the USGS New Jersey District's preparation 

room as a check of possible contamination at the NWQL. The second sample was brought into the field to 

a site where pesticides had been detected previously in ground-water samples. This sample was a check to 

determine whether sampling procedures may introduce contaminants into the water samples. No pesticides 

were detected in the either the field-blank or laboratory-blank water samples. These results indicate that 

contamination of water samples by pesticides in the field or in the laboratory was unlikely. The third 

deionized water sample was spiked in the New Jersey District's laboratory with known concentrations of 

carbamate insecticides and triazine and acetanilide herbicides. The NWQL detected all the pesticides in the 

sample at concentrations at or near the known concentrations.

10
Table 2. Physical characteristics and chemical constituents measured in the field and determined 

in the laboratory in water samples during each sampling event

[°C, degrees Celsius; mg/L, milligrams per liter; ug/L, micrograms per liter, CaCO^ calcium 

carbonate; uS/cm; microsiemens per centimeter at 25 degrees Celsius; N, nitrogen; P, phosphorous]

Water-quality characteristic

or constituent

Minimum

laboratory

reporting

level 1

Sampling event

2 3 4

Physical characteristics and constituents 

measured in the field

Water temperature (°C) 0.1

pH .1

Dissolved oxygen (mg/L) . 1

Alkalinity (mg/L as CaCO3) 11

Specific conductance (p.S/cm) 1

Laboratory analyses

Dissolved major ions (mg/L) .1

Dissolved metals variable 

ItolO

Dissolved nutrients (mg/L)

Nitrate plus nitrite (as N) .01

Nitrite (as N) .01

Ammonia (as N) .01

Ammonia plus organic nitrogen (as N) .2

Orthophosphate (as P) .01

Nitrogen N ' isotope ratio (8N , in per mil) .1

Bacteria (colonies per 100 milliliters)

Fecal coliform bacteria 1

Fecal streptococci bacteria 1

Dissolved organic carbon (mg/L) .1

Methylene blue active substances (MBAS) (mg/L) .01

Volatile organic compounds (p.g/L) .2

Carbamate insecticides (p.g/L) .5

Triazine and acetanilide herbicides (|J.g/L) .05

Yes 1 

Yes 

Yes 

Yes 

Yes

Yes 

Yes

Yes 

Yes 

Yes 

Yes 

Yes

Yes

Yes 

Yes

Yes 

Yes

Yes 

Yes 

Yes

Yes 

Yes 

Yes 

Yes 

Yes

No

No

Yes 

Yes 

Yes 

Yes 

Yes

Yes

Yes 

Yes

No 

Yes

No 

Yes 

Yes

Yes 

Yes 

Yes 

Yes 

Yes

No 

No

Yes 

Yes 

Yes 

Yes 

Yes

Yes

Yes 

Yes

No 

Yes

No 

Yes 

Yes

Yes 

Yes 

Yes 

Yes 

Yes

No 

No

Yes 

Yes 

Yes 

Yes 

Yes

No

Yes 

Yes

No 

No

No 

No 

No

1A "yes" indicates that water samples were collected and analyzed for the indicated characteristic or constituent. A "no" indicates that samples were not collected for this analysis.

11
During the fourth sampling event, two samples containing deionized water were taken into the field 

to sites in agricultural areas of the New Jersey Coastal Plain where fecal streptococci bacteria had been 

detected previously in ground-water samples. The deionized water samples were exposed to the air to 

determine whether samples had been contaminated by airborne fecal streptococci bacteria. Those samples 

exposed to the air contained small concentrations of fecal streptococci bacteria, indicating that 

contamination of the samples in the field was likely. For this reason, any results relating the presence of 

fecal streptococci bacteria to concentrations of nitrate in ground water are used with caution.

The results of the quality-assurance program indicate that the concentrations of constituents reported 

by the NWQL are reasonable and that sampling procedures (except in the case of fecal streptococci 

bacteria) and laboratory procedures did not introduce biases in the water-quality analyses.

Quantification of Land Use Near a Well

For the regional data set used to evaluate the effects of land use on shallow-ground-water quality at a 

regional scale, percentages of undeveloped, agricultural, residential, and urban-nonresidential land within 

an 800-m-radius buffer zone centered on the wellhead were calculated from digital land-use and landcover data obtained from the National Cartographic Information Center (Anderson and others, 1976; 

Fegeas and others, 1983). The buffer zone was used as a crude measure to quantify the land area 

surrounding a well that potentially could affect water quality. Problems associated with using land use to 

predict ground-water quality are discussed in Barringer and others (1990); these problems include data 

closure, the misclassification of land uses, and spatial autocorrelation resulting from the overlapping of 

buffer zones.

For the regional data set, the predominant-land-use method was used to quantify the relation 

between ground-water quality and land use (Vowinkel and Battaglin, 1989). In the predominant-land-use 

method, the land use comprising the largest area! extent within a buffer zone is assumed to have the 

greatest effect on the quality of water from a well. A limitation of the predominant-land-use method is that 

land uses within the buffer zone that are not the predominant land use are not considered to affect 

significantly the quality of water in the well.

For the local data set, more detailed land-use data were collected in the field at the time of sampling. 

Types of land-use data collected included the presence of livestock, the use of pesticides and chemical 

fertilizers on fields and lawns near the domestic well, the locations of agricultural plots, and the distance 

between the domestic well and septic system(s).

Statistical Methods

The median and interquartile range (25th and 75th percentiles) are used to evaluate the distributions 

and central tendencies of the water-quality-constituent concentrations. The median is reported rather than 

the mean because the water-quality-concentration data typically are nonnormally distributed (skewed) and 

are left-censored (truncated) as a result of a minimum laboratory reporting level. Concentrations below the 

laboratory reporting level were assigned the same value below the laboratory reporting level to distinguish 

them from concentrations at the reporting level. Boxplots are used to summarize graphically the 

characteristics of the data sets; they display the median, quartiles, spread, skewness, and presence of 

unusual values.

Nonparametric statistical procedures were used to test hypotheses to determine differences in waterquality concentrations among groups. When applied to nonnormal data, the power of parametric 

procedures is low and their results may be in error (Helsel, 1987, p. 179). Because the data typically were 

nonnormally distributed, correlation coefficients were determined with ranked independent and dependent 

variables to evaluate linear relations between variables. The Kruskal-Wallis test was used to test 

hypotheses about the distributions of concentrations among groups. In these statistical tests, the data are 

assumed to be random and independent. Because the data from each well site may be serially

12
autocorrelated, statistical tests were conducted independently for each sampling event and the results were 

averaged over all the sampling events. If a test statistic met or exceeded a 0.05 significance level, the 

distribution of values in one group was considered significantly different from that of another group.

Multivariate statistical methods are used to identify groups of intercorrelated variables, reduce the 

number of variables being studied, and rewrite the data in an alternative form. Discriminant analysis, 

which makes use of the general linear model with nominally measured dependent variables (Johnson, 

1980, p. 225-231), was used in this study to determine whether the variability in the distributions of certain 

water-quality, well-construction, land-use, and hydrogeologic variables are similar. The statistical model 

developed in this report is used to determine which variables are useful to predict whether the 

concentration of nitrate will be below (Group 1) or equal to or greater than (Group 2) the MCL. The 

independent variables were ranked prior to the discriminant analysis to avoid problems associated with 

nonnormally distributed values and outliers.

INDICATORS OF THE SOURCES AND DISTRIBUTION OF NITRATE 

IN WATER FROM SHALLOW DOMESTIC WELLS

Land-use variables describe the sources of nitrate in the environment, whereas hydrogeologic, wellconstruction, and water-quality variables affect the distribution of nitrate in ground water. Each variable is 

tested independently to determine whether a significant association with nitrate concentration exists. 

Groups of variables are then tested to determine which variables best describe the conditions when nitrate 

in shallow ground water is equal to or greater than 10 mg/L.

Factors Affecting or Related to Nitrate Concentrations

Before testing hypotheses concerning relations among hydrogeologic, well-construction, land-use, 

and water-quality variables, it was necessary to determine whether the time of year during which the 

sample was collected or the aquifer system from which the sample was collected could affect statistical 

results. Because sample sizes generally are small, biases that can affect the results need to be eliminated or 

minimized.

Sampling Event

Because agricultural chemicals are applied seasonally (mostly during spring), variability in 

concentrations of water-quality constituents was expected in shallow wells affected by agricultural 

applications of fertilizers and pesticides. To test this hypothesis, water-quality samples were collected from 

the 12 domestic wells on four occasions during the year. Values and concentrations reported for physical 

characteristics and chemical constituents measured in the field and water-quality constituents determined 

in the laboratory were compared for significant differences among the four sampling events (table 3). The 

results indicate that concentrations of most physical characteristics and constituents were similar among 

the four sampling events. The exceptions are that the temperature of the air and ground water and the 

concentration of ammonia plus organic nitrogen differed during at least one of the four sampling events. 

The air temperature varied as expected; median temperatures ranged from 22.5 to -1.0°C. The seasonal 

variability of the temperature of the ground water was significant; however, the median water temperatures 

during the four sampling events did not differ by more than 1 °C. Concentrations of ammonia plus organic 

nitrogen (p = <0.001) and orthophosphate (p = 0.051) in ground water varied among sampling events, 

probably because the analytical technique used at the NWQL was changed to a less sensitive technique just 

prior to the third sampling run (Jacob Gibs, U.S. Geological Survey, oral commun, 1991); for this reason 

these two constituents are not used in any of the statistical comparisons in this report.

13
Table 3. Physical characteristics and chemical constituents measured in the field and concentrations of water-quality constituents for 12 shallow domestic wells in agricultural areas of the New 

Jersey Coastal Plain, by sampling event.

[°C, degrees Celsius; mg/L, milligrams per liter, CaCO3, calcium carbonate; u.S/cm; microsiemens 

per centimeter at 25 degrees Celsius; N, nitrogen; P, phosphorous; col/100 mL, colonies per 100 

milliliters; ug/L, micrograms per liter; ND, not detected; NA, not applicable. All concentrations are 

in mg/L except where noted]

Water-quality characteristic 

or constituent

Median value or concentration for sampling event Kruskal-

_________________________ Wallis test

12 34 p-value 1

.45 

<.01 

10.8

.60 

<.01 

9.7

-1.0

12.5

5.1

6.0

187

9.0

.05

8.5

12.6

5.3

8.0

187

8.7

Physical characteristics and chemical 

constituents measured in the field

Air temperature (°C) 22.5 27.5 

Water temperature (°C) 13.4 13.5 

pH 5.2 5.0 

Alkalinity (CaCO3) 3.0 2.0 

Specific conductance (j4.S/cm) 191 213 

Dissolved oxygen 8.5 8.8

Laboratory analyses

Dissolved nutrients

Ammonia (as N)

Ammonia plus organic nitrogen (as N)

Nitrite (as N) <.01 <.01

Nitrate (as N) 10.8 9.7 10.7

Orthophosphate (as P)2 <.01 <.01 <.01

Nitrogen N15/14 isotope ratio (8N15 , in per mil) 3.7 3.3 2.9

Organic constituents

Methylene blue active substances (MBAS) (mg/L) .09 .11 .12 

Fecal coliform (col/100 mL) <1 <1 <1 

Fecal streptococci (col/100 mL) 7.5 <1 <1 

Total pesticides (p.g/L) ND ND ND 

Total carbamate insecticides Qig/L) <.5 <.5 <.5 

Total triazine and acetanilide <.05 <.05 <.05 

herbicides (|J.g/L)

12.0

NA

NA

NA 

NA 

NA

<0.0001 

.028 

.763 

.839 

.772 

.607

.364 

<.0001 

.218 

.982 

.051

.152

.620

.783

.783

.879

.864

.654

The Kruskal-Wallis test is used to test the hypothesis that the distributions of values or concentrations of one or more sampling

events is different from those of the other events. A p-value equal to or less than 0.05 is considered significant. 

2 Results of analyses for ammonia plus organic nitrogen and orthophosphate differed between the second and third sampling event,

causing the significant difference among events.

14
Concentrations of nitrate in ground water from the 12 domestic wells were similar (p = 0.98) among 

the four sampling events (fig. 6). Concentrations of nitrate (as N) rarely varied by more than 1 mg/L at any 

well. Seasonal loadings of nitrate at the land surface are not apparent in water samples from these 12 wells, 

probably because the nitrate is transported and dispersed along the ground-water flow path.

zee

zi

25

20

15

5

-

S

° 0 A 4, m m a B ©

 ^

_ ffl ffl

Bl KB

EXPLANATION

O Event 1

A Event 2

+ Event 3 

D Event 4

NEW JERSEY WELL NUMBER

Figure 6. Distribution of concentrations of nitrate in water from 12 shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, by sampling event.

From these observations, several inferences are made about the quality of shallow ground water 

from wells with screened intervals between 16 and 30 m below the land surface: (1) concentrations of 

nitrate and other water-quality constituents probably do not vary seasonally; (2) sampling of wells for 

water-quality analyses more frequently than on a yearly cycle probably is not necessary; and (3) seasonal 

sampling probably does not affect statistical relations between concentrations of nitrate and other 

variables, such as land use.

Hydrogeologic Characteristics

Prior to determining the effects of land use on shallow-ground-water quality, the effects of 

hydrogeologic conditions on water quality must be considered. Water-quality characteristics and 

constituent concentrations are compared between the two aquifer systems and between wells located on or 

near the surface-water divide and those located downgradient from the divide.

Aquifer System

One of the goals of this analysis is to test the transfer value of the relations between shallow-groundwater quality and land use to other areas of similar hydrogeology and land use where water-quality data are 

sparse. Because only 12 sampling sites were used in the statistical analysis (6 in Study area 1 in the 

Potomac-Raritan-Magothy aquifer system and 6 in Study area 2 in the Kirkwood-Cohansey aquifer 

system), it was necessary to determine whether the values and concentrations of water-quality 

characteristics and constituents are similar between the two aquifer systems (table 4). If the values are

15
Table 4. Physical characteristics and chemical constituents measured in the field and concentrations of water-quality constituents for 12 shallow domestic wells in agricultural areas of the New 

Jersey Coastal Plain, by aquifer system

[ C, degrees Celsius; mg/L, milligrams per liter, CaCC^, calcium carbonate; ja.S/cm, microsiemens 

per centimeter at 25 degrees Celsius; N, nitrogen; P, phosphorous; col/100 mL, colonies per 100 

milliliters; |xg/L, micrograms per liter; ND, not detected; NA, not applicable. All concentrations are 

in mg/L except where noted]

Median value or concentration for the:

Water quality Study area 1 Study area 2 Kruskalcharacteristic Potomac-Raritan- Kirkwood-Cohansey Wallistest

constituent Magothy aquifer system aquifer system p-value1

Physical characteristics and chemical 

constituents measured in the field

Water temperature (°C) 12.4 13.7 <0.0001

pH 5.4 4.6 <.0001

Alkalinity (as CaCC^) 7.5 <.l <.0001

Specific conductance (in u.S/cm) 168 211 .278

Dissolved oxygen 8.7 9.0 .373

Laboratory analyses

Dissolved nutrients

Ammonia (as N) <.l <.l .879 

Nitrite (as N) <01 <.01 .373 

Nitrate (as N) 9.3 12 .671

Nitrogen N15/14 isotope ratio (5N15, in per mil) 2.9 3.5 .447

Organic constituents

Dissolved organic carbon .3 .4 .257 

Methylene blue active substances (MB AS) (mg/L) .09 .12 .356 

Fecal coliform (col/100 mL) <1 <1 .498 

Fecal streptococci (col/100 mL) <1 3 .113

Total pesticides (|j.g/L) ND ND .741

Total carbamate insecticides (|J.g/L) <.5 <.5 .583

Total triazine and acetanilide herbicides (|J.g/L) <.05 <.05 .396

lrThe Kruskal-Wallis test is used to test the hypothesis that the distribution of values or concentrations in one 

aquifer system is different from that in the other aquifer system. A p-value equal to or less than 0.05 is considered to be significant.

16
similar between the two aquifer systems, then combining the data sets from both aquifer systems would not 

be expected to introduce biases when testing hypotheses related to the effects of other hydrogeologic, wellconstruction, and land-use factors on shallow-ground-water quality.

The values of some of the physical characteristics and concentrations of chemical constituents in 

water samples measured in the field differed between the two aquifer systems; however, the concentrations 

of most water-quality constituents generally were similar between the two aquifer systems. The pH and 

alkalinity of shallow ground water in agricultural areas were significantly lower in the outcrop area of the 

Kirkwood-Cohansey aquifer system than in the outcrop area of the Potomac-Raritan-Magothy aquifer 

system. The median pH of shallow water was about 0.5 pH units lower in the outcrop area of the 

Kirkwood-Cohansey aquifer system than in the outcrop area of the Potomac-Raritan-Magothy aquifer 

system.

The results of the statistical analysis indicate that values and concentrations of most water-quality 

characteristics and constituents generally are similar between the two aquifer systems. The distributions of 

concentrations of nitrate in shallow ground water in agricultural areas are similar (p = 0.67) in both aquifer 

systems. This result indicates that combining the data from the two aquifer systems to test hypotheses 

probably does not significantly affect the statistical results when comparing other variables. Also, this 

suggests that there is transfer value of the relations between ground-water quality and land use to other 

areas of similar conditions where water-quality data is scarce.

Hydroaeoloqic Scenario

Domestic wells used to supply drinking water to farm homes typically are located at higher 

elevations near the surface-water divide or at lower elevations near discharge areas such as streams or 

ponds. Nitrate concentrations were expected to be larger in water from domestic wells near the divide 

where the ground water is relatively young than in water from domestic wells near a stream where the age 

of the water commonly is much older.

In water from the 12 domestic wells in the local data set, the median concentration of nitrate was 

larger in those five wells near (less than 250 m from) the surface-water divide than in those seven wells 

downgradient (equal to or greater than 250 m) from the divide (table 5 and fig. 7). The median 

concentration of nitrate (as N) in shallow ground water in agricultural areas was 12 mg/L near the divide 

and 8.3 mg/L downgradient from the divide. The range of concentrations of nitrate in ground water near 

the surface-water divide is relatively small, partly because the ground-water flow paths are short and the 

water is young. The range of concentrations of nitrate in water from the wells downgradient from the 

divide is larger, possibly as a result of the dispersion of the nitrates along the ground-water flow path; also, 

in some cases, the water is too old to have been affected by nitrate sources at the land surface.

Well-Construction Characteristics

Prior to determining the effects of land use on shallow-ground-water quality, the effects of well 

construction on water quality must be determined. Water-quality characteristics and constituent 

concentrations are compared between well types and wells of different depth.

Type of Well

The type of well sampled may bias results when comparing regional water quality to land-use or 

other factors. Domestic wells in the outcrop area of the Potomac-Raritan-Magothy aquifer system typically 

are shallow and are screened in unconfined parts of the aquifer system, whereas irrigation wells typically 

are deeper and are screened in confined parts of the aquifer system. Domestic and irrigation wells in the 

Kirkwood-Cohansey aquifer system, commonly are of similar depths and generally are screened in 

unconfined parts of the aquifer system.

17
Table 5. Statistical summary of the concentrations of nitrate in water from 12 shallow domestic 

wells in agricultural areas of the New Jersey Coastal Plain, by location of the well relative to the 

surface-water divide

[<, less than; >, equal to or greater than; m, meter]

Concentration of nitrate as nitrogen, 

in milligrams per liter

Location of the well

relative to the Number of

surface-water divide wells/samples

25th 

percentile Median

75th 

percentile

KruskalWallis test 

p-value

Downgradient (> 250 m) 7/28 

Near(<250m) 5/20 9.3

8.3

12

14

14

0.39

tt>

<

LLjCfl 

2<OCcC

toZ 5=

LL_UJ

25

ro o

-* in

ZZ-1 10

HZ"^ 0-cc 

5

zz

o 

o

DOWNGRADIENT NEAR

EXPLANATION

OUTLIER

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER-The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

LOCATION OF THE WELL RELATIVE 

TO THE SURFACE-WATER DIVIDE

Figure 7. Distributions of concentrations of nitrate in water from 12 shallow domestic wells in 

agricultural areas of the New Jersey Coastal Plain, by location of the well relative to the surfacewater divide.

18
To determine whether the type of well sampled may bias statistical results, wells from the regional 

data set in predominantly agricultural areas with screened intervals equal to or less than 30 m below the 

land surface were selected to determine whether concentrations of nitrate in water are similar in samples 

from domestic and irrigation wells (table 6 and fig. 8). The results of the analysis indicate that the 

concentrations of nitrate in shallow ground water in agricultural areas are similar (p = 0.23) in domestic 

and irrigation wells. The median concentration of nitrate (as N) in shallow ground water was 8.5 mg/L in 

domestic wells and 9.8 mg/L in irrigation wells. The results indicate that the type of well sampled probably 

does not affect the relation between the concentration of nitrate in shallow ground water and the 

predominant land use surrounding the well. Because the concentrations of nitrate are similar in water from 

domestic wells and irrigation wells, it is suspected that agricultural land-use practices rather than septic 

systems may be the predominant source of nitrate in water from domestic wells.

Well Depth

All wells completed in the unconsolidated sediments of the New Jersey Coastal Plain have screens, 

and almost all wells are screened in only one aquifer. The depth of the well is defined by the depth to the 

top and the depth to the bottom of the screened interval below the land surface. The median depth to the 

bottom of the screened interval of a domestic well in the Coastal Plain of New Jersey is about 25 m. The 

screened lengths typically are from 1 to 10 m with a median length of about 3 m. The location of the well 

along the ground-water flow path and the depth of the well probably affect the concentrations of nitrate 

measured in water from the well. The concentration of nitrate in ground water was expected to decrease 

with depth in the aquifer.

In the local data set, the concentration of nitrate observed in ground water is affected by well depth. 

The depths to the top of the screened interval (p = 0.189) and the depths to the bottom of the screened 

interval (p=0.108) are shallower in wells in which the concentrations of nitrate exceeded the MCL than in 

wells in which the concentrations were less than the MCL (table 7 and fig. 9). The depth to the top of the 

screened interval typically was less than 20 m in those wells containing water with concentrations of 

nitrate greater than the MCL.

Other Water-Quality Characteristics and Constituents

Results of analyses of ground-water samples for physical characteristics and chemical constituents in 

the field and for chemical constituents in the laboratory may be useful indicators of sources of nitrate 

contamination in ground water and of whether the concentration of nitrate in the ground water is likely to 

exceed the MCL.

The physical characteristics of and chemical constituents in ground water measured in the field at the 

time the sample was collected were specific conductance, dissolved-oxygen concentration, pH, alkalinity, 

and temperature. If any of these characteristics was related to the concentration of nitrate in the ground 

water, it would provide a quick and inexpensive screening technique to determine whether the 

concentration of nitrate is large and may exceed the MCL. Results of statistical tests indicate that the 

values of pH, alkalinity, and temperature of the water sample are not significantly related to the 

concentration of nitrate, whereas the specific conductance of and the concentration of dissolved oxygen in 

the water sample are significantly related to the concentration of nitrate in the sample. The relation of 

specific conductance and dissolved-oxygen concentration to nitrate concentration are discussed later in the 

report.

It was expected that if the quality of water in wells in the local data set was affected by effluent from 

a septic system, contaminants such as fecal coliform bacteria, certain volatile organic compounds (VOC's), 

such as those found in household cleaners, and methylene blue active substances (MBAS), which are 

found in detergents, may be present in the water samples. None of the 31 VOC's analyzed for was reported 

at concentrations greater than the laboratory reporting level concentration of 0.2 jj,g/L in water samples 

from any of the 12 domestic wells. Fecal coliform bacteria were detected in three water samples and at a

19
Table 6. Statistical summary of the concentrations of nitrate in shallow ground water in predominantly agricultural areas of the New Jersey Coastal Plain, bv type of well

Concentration of nitrate as nitrogen, 

in milligrams per liter

Type of well

Number of 

wells/samples

25th 

percentile Median

75th 

percentile

KruskalWallis test 

p-value

Domestic 

Irrigation

28/28 

17/17

3.4 

5.0

8.5 

9.8

12.8

21.5

0.233

o

«> on

: NITRATE A

LLIGRAMS 

 R

ro c

o enc

05h- 15

zz-1

O~oc 10

<UJ°-

°£C3 5

z°

Sfc o 

zz

0

-

" 

_

> 

>

_l

^ c

IRRIGATION

TYPE OF WELL

EXPLANATION

OUTLIER

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER--The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

Figure 8. Distributions of concentrations of nitrate in shallow ground water in predominantly agricultural areas of the New Jersey Coastal Plain, by type of well.

20
Table?. Statistical summary of the depths to the top of the screened interval for 12 shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant level for nitrate

Depth to the top of the screened interval, 

in meters below the land surface

Concentration of

nitrate as nitrogen, Number of 25th

in milligrams per liter wells/samples percentile Median

75th 

percentile

KruskalWallis test 

p-value

Less than 10 

10 or greater

6/24 

6/24

18.3

14.6

21.5

17.8

23.2

19.2

0.189

CE

LULU

0. _Ej £<»

ILU Z

2 ' 

XLu2

J-ZLU Q-LUffi 

LULU

Qcr

0

25 

20

15 

10 

5 

n

_

T -

_L_

TT

LESS THAN 10 GREATER THAN OR 

EQUAL TO 10

CONCENTRATION OF NITRATE AS NITROGEN, 

IN MILLIGRAMS PER LITER

EXPLANATION

OUTLIER

UPPER WHISKER-The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER-The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

Figure 9. Distributions of the depths to the top of the screened interval of 12 shallow domestic 

wells in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant 

level for nitrate.

21
maximum concentration of 3 col/100 mL; all of these samples contained concentrations of nitrate (as N) 

greater than 10 mg/L. Because VOC's and fecal coliform bacteria generally are not present in water 

samples from the local data set, these results indicate that the effect of the septic systems on the quality of 

water in, and concentrations of nitrate in samples from, the wells was minor, probably because none of the 

septic systems was located upgradient from the well.

Specific Conductance

Specific conductance is a measure of the conductance of water of a unit length and unit cross section 

at a specified temperature; it is reported in units of (iS/cm (microsiemens per centimeter at 25° Celsius). 

Specific-conductance values provide an indication of the concentration of total ions in solution. A 

significant positive relation between the values of specific conductance and the concentration of nitrate in 

the ground-water samples was expected because the nitrate ions contribute to the specific conductance of 

the water.

In water samples from the local data set, the values of specific conductance were significantly 

different (p = 0.005) in water from wells in which the concentration of nitrate exceeded the MCL than in 

water from wells in which the concentration of nitrate was less than the MCL (table 8 and fig. 10). In all 

cases except one, the specific conductance of the water sample was greater than 200 uS/cm when the 

concentration of nitrate exceeded the MCL. The correlation coefficient between the ranked concentrations 

of nitrate and specific conductance is 0.82. These results indicate that specific conductance increases as the 

concentrations of nitrate and other ions such as chloride, sulfate, calcium, and magnesium increase. Nitrate 

ions commonly constitute a large percentage of the ions contributing to the specific conductance of ground 

water in agricultural areas.

Dissolved Oxygen

The concentration of dissolved oxygen in ground water can provide an indication of whether the 

ground water was recently in contact with the atmosphere and whether oxygen has been consumed as a 

result of geochemical or microbiological reactions with inorganic and organic substances in the subsurface. 

When oxygen is present in ground water, ammonia in the system usually is converted to nitrate by 

nitrifying bacteria. Conversely, if dissolved oxygen is absent in ground water, anaerobic denitrifying 

bacteria can reduce the nitrate in the ground water.

In the regional data set, concentrations of dissolved oxygen in shallow ground water in agricultural 

areas typically were greater than 3 mg/L; the median concentration of dissolved oxygen in shallow ground 

water was 8.4 mg/L in the Potomac-Raritan Magothy aquifer system and 7.4 mg/L in the KirkwoodCohansey aquifer system. Because shallow ground water in agricultural areas typically contains dissolved 

oxygen, the predominant form of nitrogen in the ground water is nitrate.

In the local data set, the concentration of dissolved oxygen in water from shallow wells was larger 

(p = 0.26) in wells where the concentration of nitrate exceeded the MCL than in wells where the 

concentration of nitrate was less than the MCL (table 9 and fig. 11). The concentration of dissolved oxygen 

in ground water was larger than 6 mg/L in water from wells containing water with a concentration of 

nitrate greater than the MCL. Concentrations of dissolved oxygen are typically less than 1 mg/L in water 

from wells near discharge areas. A positive correlation between the ranked concentrations of nitrate and 

dissolved oxygen in ground water was observed (r = 0.81).

22
Table 8. Statistical summary of values of specific conductance of water from 12 shallow domestic 

wells in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant 

level for nitrate

Specific conductance, 

in microsiemens per centimeter at 25 degrees Celsius

Concentration of

nitrate as nitrogen, Number of 25th

in milligrams per liter wells/samples percentile Median

75th 

percentile

KruskalWallis test 

p-value

Less than 10 

10 or greater

6/23 

6/24

153

218

162

295

165

387

0.005

cc

HI ZH 500

2 ^ 400

<HIIU 

HOO

liJliJ

8i2200

o^S

LLLLJLO

ow~

£g<

WQ

- 

0 0

LESS THAN 10 GREATER THAN OR 

EQUAL TO 10

CONCENTRATION OF NITRATE AS NITROGEN, 

IN MILLIGRAMS PER LITER

EXPLANATION

OUTLIER

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE 

MEDIAN

25th PERCENTILE

LOWER WHISKER--The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

Figure 10. Distributions of values of specific conductance of water from 12 shallow domestic wells 

in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant level 

for nitrate.

23
Table 9. Statistical summary of concentration of dissolved oxygen in water from 12 shallow 

domestic wells in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant level for nitrate

Concentration of dissolved oxygen, 

in milligrams per liter

Concentration of 

nitrate as nitrogen, 

in milligrams per liter

Number of 

wells/samples

25th 

percentile Median

75th 

percentile

KruskalWallis test 

p-value

Less than 10 

10 or greater

6/23 

6/23

0.2 

8.0

8.6 

9.0

9.1 

9.7

0.26

cc

QUJ

0*

Q i

zo

on

fl

LESS THAN 10 GREATER THAN OR 

EQUAL TO 10

CONCENTRATION OF NITRATE AS NITROGEN, 

IN MILLIGRAMS PER LITER

EXPLANATION

OUTLIER

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER--The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

Figure 11. Distributions of concentrations of dissolved oxygen in water from 12 shallow domestic 

wells in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant 

level for nitrate.

24
Stable Isotopes of Nitrogen

Ratios of stable isotopes of nitrogen can be used to determine possible sources of nitrate 

contamination in water. The isotopic composition of N2 (nitrogen) in a water sample is expressed in terms 

of its 6N15 value where

8N (°/00) = [(^sample " ^standard) / ^standard! x ^ 

In the common practice for stable-isotope notation, R, is denned as the atomic N15/N14 ratio. 

Because the isotopic concentration is considered to be globally uniform, the standard is the ratio for 

atmospheric N2 (Heaton, 1986). Most fertilizers used for agricultural purposes are processed by means of 

the Haber process, which incorporates atmospheric nitrogen. The isotopic signature of atmospheric N2 is 

0.0 SN150/^

A 8N15 value for a water sample from -2 to 7 °/00 indicates that the source is from commercial 

fertilizers, whereas a value from 10 to 23 °/00 indicates that the source is from animal wastes (Tyler 

Coplen, U.S. Geological Survey, written commun., 1990). Kreitler and others (1978) demonstrated a 

relation between land use and N15 values for shallow ground water on Long Island, New York. The 8N 

values for water from the upper glacial aquifer were isotopically lighter where the land was predominantly 

agricultural than where the land was predominantly suburban and serviced by septic systems or sewers. 

The authors suggest that chemical fertilizers are the predominant source of nitrogen in ground water in 

agricultural areas and human wastes from septic systems are the primary source of nitrogen in ground 

water in the residential areas on Long Island.

6N15 values for the local set ranged from 1.5 to 6.3 °/00; these are below the range of 8N15 values in 

water containing nitrogen solely from animal sources. The 6N15 values indicate that the nitrogen is 

isotopically heavier (p = 0.06) in water from wells that contained a concentration of nitrate greater than the 

MCL (table 10 and fig. 12) than in water from wells that contained a concentration of nitrate less than the 

MCL. The 5N15 values for the water samples from wells in areas where livestock were present were 

similar (p = 0.19) to those from wells located in areas where livestock were absent. These results indicate 

that the predominant source of nitrate in samples in the local data set was probably chemical fertilizers 

rather than livestock wastes or effluent from septic systems.

Pesticides

Results of statistical analyses of constituent concentration data from the regional data set indicate a 

significant relation between the concentration of nitrate and the presence of pesticides in shallow ground 

water in agricultural areas (Louis and Vowinkel, 1989). Pesticides were detected in water from 33 percent 

of the 81 sampled wells; pesticides were detected in 43 percent of the irrigation wells, 29 percent of the 

domestic wells, and 10 percent of the public supply wells. The frequency with which the concentrations of 

one or more pesticides in water were above the laboratory reporting level was similar for the domestic and 

irrigation wells. The concentrations of nitrate were significantly different (p = 0.004) in water samples 

from the 27 wells where pesticides were present than those from the 54 wells where pesticides were absent.

Samples collected from wells in the local data set during the first three sampling events were 

analyzed fortriazine and acetanilide herbicides and carbamate insecticides (app. 2F and 2G). Atrazine, 

alachlor, metolachlor, metribuzin, and carbofuran were the most frequently reported pesticides in ground 

water. Concentrations of one or more pesticides were above the minimum reporting level in water from 

four wells during all three sampling events and in water from a fifth well during only one sampling event.

25
Table 10. Statistical summary of values of 5N15 in water from 12 shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant level for 

nitrate

Nitrogen N15/14 isotope ratio (8N15, in per mil)

Concentration of

nitrate as nitrogen, Number of

in milligrams per liter wells/samples

25th 

percentile Median

75th 

percentile

KruskalWallis test 

p-value

Less than 10 

10 or greater

6/15 

6/18

2.0 

3.2

2.6 

3.8

3.2 

4.5

0.06

DC

Ijj _ 

Q.-I

Occ

CflLU 

Q_

zz

LESS THAN 10 GREATER THAN OR 

EQUAL TO 10

CONCENTRATION OF NITRATE AS NITROGEN, 

IN MILLIGRAMS PER LITER

EXPLANATION

OUTLIER

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER-The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

Figure 12. Distributions of values of 8N15 in water from 12 shallow domestic wells in agricultural 

areas of the New Jersey Coastal Plain, relative to the maximum contaminant level for nitrate.

26
A significant relation between nitrate concentration and the presence of one or more pesticides in ground 

water was observed (table 11 and fig. 13). The concentrations of nitrate in the water samples were 

significantly different in wells with water that contained pesticides than in wells with water that did not 

contain pesticides (p = 0.022). In all but one of the samples that contained a pesticide, the concentration of 

nitrate was above the MCL.

Land-Use Activities

The concentrations of nitrate in water from shallow wells previously was shown to be significantly 

related to land use at the regional scale (Vowinkel, 1991). Detailed land-use information near the 12 

domestic wells was collected to evaluate the effects of the presence of livestock, septic systems, and land 

uses surrounding the well on the water quality.

Presence of Livestock

Because livestock are kept in small areas, nitrogen compounds derived from their wastes typically 

are a source of large concentrations of nitrate in ground water in agricultural areas. Livestock are raised at 

4 of 12 sites at which ground water was sampled. It was suspected that the concentration of nitrate in water 

from shallow domestic wells would be larger at farms where livestock were present within 400 m of the 

wellhead than in water from the domestic wells where livestock were absent.

In water samples in the local data set, the concentrations of nitrate were similar (p = 0.74) between 

the four sites where livestock were present and the eight sites where livestock were absent (table 12 and 

fig. 14). The distributions of concentrations of nitrate in ground water in both groups show considerable 

overlap. Both groups contain samples with concentrations of nitrate greater than the MCL; however, the 

smallest concentrations of nitrate in water samples are not associated with wells near livestock. These 

results indicate that nitrogen loads from fertilizers alone and loads from fertilizers and farm-animal wastes 

can cause concentrations of nitrate in ground water to exceed the MCL.

Distance of the Wellhead from the Septic System

A field evaluation of the location(s) and distance(s) of the septic system(s) and the domestic well 

relative to the probable direction of ground-water flow was conducted for each of the 12-domestic well 

sites in the local data set. During the well-selection process, no wells were found that were directly 

downgradient from a septic system. The lateral distance between the well and the septic system was 

estimated in the field. The direction of ground-water flow was estimated by observing the locations of the 

highest elevation (surface-water divide) and the lowest elevation (discharge area). The five wells near the 

surface-water divide probably were the only wells that could be affected by effluent from a septic system 

because the elevations of the septic system and the wellhead at these five sites were similar.

If effluent from septic systems affects the concentration of nitrate in water from the wells in the local 

data set, a negative relation between the distance of the wellhead from the septic system and the nitrate 

concentration would be expected. Additionally, the distance would be expected to be shorter for those 

wells containing water with nitrate in concentrations equal to or greater than the MCL than for those 

containing water with nitrate concentrations less than the MCL. A low positive correlation between the 

ranked distance and ranked nitrate concentration (r = 0.13) was determined. The distributions of the 

distances from the well to the septic system are similar (p = 0.41) for wells containing water with nitrate 

concentrations equal to or greater than the MCL and those wells containing water with nitrate 

concentrations less than the MCL (table 13 and fig. 15). These results indicate that the distance between the 

septic system and the domestic well is not related to the concentration of nitrate in water from the wells in 

this data set.

27
Table 11. Statistical summary of concentrations of nitrate in water from 12 shallow domestic wells 

in agricultural areas of the New Jersey Coastal Plain, by the presence of pesticides in the water 

samples

Concentration of nitrate as nitrogen, 

in milligrams per liter

Presence of pesticides 

in water sample

Number of 

wells/samples

25th 

percentile Median

75th 

percentile

KruskalWallis test 

p value

Absent 

Present

7/23 

5/13

0.1 

7.9

8.5 

10.7

12

14

0.022

LUC/>

25

20

15

10

CC(rj 

°

ABSENT PRESENT

PRESENCE OF PESTICIDES IN 

WATER SAMPLE

EXPLANATION

OUTLIER

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER--The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

Figure 13. Distributions of concentrations of nitrate in water from 12 shallow domestic wells in 

agricultural areas of the New Jersey Coastal Plain, relative to the presence of pesticides in the water 

samples.

28
Table 12. Statistical summary of the distributions of concentrations of nitrate in water from 12 

shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, by the presence of 

livestock near the wellhead

Concentration of nitrate as nitrogen, 

in milligrams per liter

Presence of livestock Number of 

near wellhead wells/samples

25th 

percentile Median

75th 

percentile

KruskalWallis test 

p value

Absent 

Present

8/32 

4/16

2.1 

9.0

9.3

12.5

14 

13.!

0.74

UJ</J il

to

zn

"--a: osj

zzt g--i 

HZ'OC

<LULLJ

FC3°-

zz

8JS

20

15

10

ABSENT PRESENT

PRESENCE OF LIVESTOCK NEAR 

THE WELLHEAD

EXPLANATION

OUTLIER

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER-The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

Figure 14. Distributions of concentrations of nitrate in water from 12 shallow domestic wells in 

agricultural areas of the New Jersey Coastal Plain, relative to the presence of livestock near the 

wellhead.

29
Table 13. Statistical summary of the distances between the wellhead and the septic system for 12 

shallow domestic wells in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant level for nitrate

Distance between well and septic system, 

in meters

Concentration of

nitrate as nitrogen, Number of 25th

in milligrams per liter wells/samples percentile Median

75th 

percentile

KruskalWallis test 

p value

Less than 10 

10 or greater

6/24 

6/24

18

17

30

26

49

28

0.41

Q

ZW

<QC

H-HU1C/5 

CQ>

UJ W 

00

80

60

40

20

LESS THAN 10 GREATER THAN OR 

EQUAL TO 10

CONCENTRATION OF NITRATE AS NITROGEN, 

IN MILLIGRAMS PER LITER

EXPLANATION

OUTLIER

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER-The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

Figure 15. Distributions of distances between the wellhead and the septic system for 12 shallow 

domestic wells in agricultural areas of the New Jersey Coastal Plain, relative to the maximum contaminant level for nitrate.

30
Predominant Land Use Surrounding the Wellhead

Natural sources of nitrate in ground water in undeveloped areas are limited, although nitrate can be 

transported from agricultural and urban areas through atmospheric deposition and ground-water and 

surface-water flow. In agricultural areas, sources of nitrate to ground water include septic systems, crop 

fertilizers, and manure from stock and poultry farms. Nitrate concentrations were expected to be smallest 

in ground water beneath undeveloped areas because human sources of nitrate are scarce, whereas the 

largest concentrations of nitrate were expected beneath agricultural land as a result of the presence of 

multiple sources and the high intensity of nitrate use.

The relation between the concentration of nitrate in shallow ground water and land use for each 

aquifer system was tested by using data sets with a minimum well-separation distance of 1,600 m and the 

predominant land use within an 800-m-radius buffer zone of the wellhead (table 14). Nitrate concentrations 

in shallow ground water in undeveloped areas were smaller than concentrations in agricultural areas; the 

median nitrate (as N) concentration in undeveloped areas was less than the laboratory reporting level of 

0.1 mg/L for both aquifer systems.

Nitrate in shallow ground water in agricultural areas comprises about 75 percent of the total nitrogen 

concentrations in ground water in the outcrop area of the Potomac-Raritan-Magothy aquifer system and 

about 90 percent of the total nitrogen concentrations in ground water in the outcrop area of the KirkwoodCohansey aquifer system (table 15). Nitrate is predominant over ammonia in part because the ground water 

in agricultural areas typically contains oxygen, and ammonia is converted to nitrate by microorganisms.

The distributions of concentrations of nitrate in shallow ground water in agricultural areas are 

similar in both aquifer systems (fig. 16). The median concentrations of nitrate (as N) in shallow ground 

water from agricultural areas in the outcrop areas of the Kirkwood-Cohansey aquifer system and the 

Potomac-Raritan-Magothy aquifer system were 7.2 mg/L and 8.5 mg/L respectively; concentrations 

exceeded the MCL in water from more than 33 percent of the wells in both aquifer systems.

Concentrations of nitrate in shallow ground water were expected to increase as the percentage of 

agricultural land near a well increased. A positive correlation (r = 0.81) was determined between the 

ranked concentration of nitrate in water from shallow domestic wells and the ranked percentage of 

agricultural land within 800-m-radius buffer zones of the wellheads (fig. 17). Domestic wells surrounded 

by more than 50 percent agricultural land have a greater chance of being contaminated by sources of 

nitrates from agricultural practices that are upgradient from the well. In water from wells surrounded by 

less than 50 percent agricultural land, the concentration of nitrate (as N) was typically between 3 and 10 

mg/L but rarely exceeded 10 mg/L. Elevated concentrations of nitrate in water from shallow domestic 

wells where agriculture is less than 50 percent of the land use near the well may result from (1) the 

transport of nitrates in ground water from agricultural areas that are upgradient from the well, (2) the 

transport of wastes from septic systems near the well, (3) the use of lawn fertilizers, and (4) the conversion 

of previously agricultural land surrounding the well to other land uses since the early 1970's, when the 

land-use data used in the analysis were collected. The fourth scenario is likely because much of the 

agricultural land in New Jersey was converted to other land uses from the 1940's to the 1970's.

Multivariate Statistical Model to Predict Nitrate Concentrations

Discriminant analysis was used to determine those variables (table 16) that best describe the 

presence of nitrate in water samples from shallow domestic wells in agricultural areas in the local data set. 

Several combinations of variables were used to predict into which of two groups the water samples would 

fall: (1) nitrate concentration is less than the MCL, or (2) nitrate concentration is equal to or greater than 

the MCL. Some variables are better predictors of nitrate concentrations in Group 1, whereas other 

variables are better predictors of nitrate concentrations in Group 2. For example, the presence or absence of 

livestock predicted correctly 86.4 percent of the observations in Group 1 but only 50 percent of the 

observations in Group 2.

31
Table 14. Statistical summary of concentrations of nitrate in shallow ground water in the 

New Jersey Coastal Plain, by predominant land use

[<, less than the laboratory reporting level]

Concentration of nitrate as nitrogen, 

in milligrams per liter

Aquifer system Predominant Number of 25th 

outcrop area land use wells/samples percentile Median

75th 

percentile

KruskalWallis test 

p value

KirkwoodCohansey

PotomacRaritanMagothy

Undeveloped 

Agricultural

Undeveloped 

Agricultural

99/99 

36/36

15/15 

24/24

4.1

1.2

7.2

.1 

8.5

0.7 

14.8

1.2 

12.8

0.001

<.001

LU</5

P

tS

ZH

"--t 

02

Q--J

<LULU 

CC(rjQm t-

§5

8^

30

ro 01

rvs o

15

10

EXPLANATION

CKKD MRPA

OUTLIER

AQUIFER SYSTEM OUTCROP AREA

UPPER WHISKER--The largest data value greater 

than or equal to the upper quartile plus 1.5 

times the interquartile range

75th PERCENTILE

MEDIAN

25th PERCENTILE

LOWER WHISKER--The smallest data value less 

than or equal to the lower quartile minus 

1.5 times the interquartile range

AQUIFER SYSTEM 

CKKD Kirkwood-Cohansey 

MRPA Potomac-Raritan-Magothy

Figure 16. Distributions of concentrations of nitrate in shallow ground water in predominantly 

agricultural areas of the New Jersey Coastal Plain, by aquifer system.

32
Table 15. Mean ratio of concentrations of dissolved-nitrogen species to concentrations of all dissolved nitrogen in water from shallow wells in predominantly agricultural areas of the New Jersey 

Coastal Plain, in the regional data set

[<, less than]

Nitrogen species

Aquifer system 

outcrop area

Number of 

wells/samples Nitrate Nitrite Ammonia

Organic 

nitrogen

Kirkwood-Cohansey 24/24 

Potomac-Raritan-Magothy 23/23

88.9

74.4

0.9 

8.5

10.3

17.1

30

LU 25

8cr 

zfE 20

15

a 10

Q3

Si a fe~ 5

8 0 

oooo

o° o 0

oo

O 

O

%^

<9

20 40 60 80 

PERCENTAGE OF AGRICULTURAL LAND

100

Figure 17. Relation between concentrations of nitrate in water from shallow domestic wells and 

the percentage of agricultural land within 800-meter-radius buffer zones of the wellhead.

33
Data sets for the independent and dependent variables listed in table 16 were complete for a total of 

46 samples; nitrate concentrations were below the MCL in 22 of the samples and were equal to or greater 

than the MCL in 24. Specific conductance was the single best discriminator between nitrate concentrations 

below and above the MCL; it was able to predict correctly more than 90 percent of the nitrate 

concentrations in Group 1 and Group 2. The variables 8N15 value, depth to the bottom of the screened 

interval, and presence or absence of pesticides were able to correctly predict whether the concentration of 

nitrate was in Group 1 or Group 2 more than 70 percent of the time.

The variables specific conductance, presence or absence of pesticides, presence or absence of 

livestock, and concentration of dissolved oxygen were able to predict correctly 100 percent of nitrate 

concentrations in both Group 1 and Group 2 (table 17). Because specific conductance explained about 95.5 

percent of the nitrate concentrations in either Group 1 or Group 2, little predictive information is gained by 

including the other variables. When the variable specific conductance was excluded, the best model for 

predicting nitrate concentrations in Groups 1 and 2 combined included the variables depth to the top of the 

screened interval, the presence or absence of pesticides, and the presence or absence of livestock. This 

model correctly predicted nitrate concentrations in 90.9 percent of the samples in Groups 1 and 2.

In general, the model results indicate that the conditions that best describe those domestic wells in 

agricultural areas containing water with concentrations of nitrate equal to or greater than the MCL (Group 

2) are associated with: specific conductance greater than 200 mg/L, top of the screened interval less than 

20 m below the land surface, concentration of dissolved oxygen greater than 6 mg/L, presence of pesticides 

in the water sample, a distance of less than 250 m between the wellhead and the surface-water divide, and 

presence of livestock near the wellhead.

SUMMARY AND CONCLUSIONS

Previously collected and new water-quality data from shallow wells (screened interval less than 

30 m below the land surface) in predominantly agricultural areas of the New Jersey Coastal Plain were 

used to determine the relation of nitrate concentrations in shallow ground water to various hydrogeologic 

and land-use factors in the study area. Information on land use, well construction, hydrogeology, and water 

quality were used to predict the conditions under which concentrations of nitrate as nitrogen in water from 

domestic wells in predominantly agricultural areas are most likely to be equal to or larger than the USEPA 

MCL of 10 mg/L.

Results of the analyses of water-quality samples collected during 1980-89 from 230 shallow wells in 

the outcrop areas of the Kirkwood-Cohansey and Potomac-Raritan-Magothy aquifer systems were used to 

evaluate the regional effects of land use on shallow-ground-water quality. Results of statistical analysis 

indicate that concentrations of nitrate in shallow ground water are significantly different (p = 0.001) in 

agricultural areas than in undeveloped areas in both aquifer systems. Concentrations of nitrate nitrogen 

exceeded the MCL in water from more than 33 percent of the 60 shallow wells in agricultural areas. 

Concentrations of nitrate in water from shallow wells in agricultural areas increased as the percentage of 

agricultural land within an 800-meter-radius buffer zone of the wellhead increased (r = 0.81). 

Concentrations of nitrate in water from domestic wells in agricultural areas were similar (p = 0.23) to those 

concentrations in water from irrigation wells. These results indicate that most of the nitrate in water from 

domestic wells in agricultural areas is derived from agricultural practices rather than from other sources, 

such as septic systems.

Water-quality samples collected from 12 shallow domestic wells in agricultural areas screened in the 

outcrop areas of the Kirkwood-Cohansey and Potomac-Raritan-Magothy aquifer systems were used to 

evaluate the local effects of hydrogeologic conditions and land-use activities on shallow ground-water

34
quality. Concentrations of water-quality constituents in these wells were similar among four sampling 

events over a 1-year span. The concentration of nitrate in water from 6 of the 12 wells exceeded the MCL. 

Concentrations of nitrate greater than the MCL are associated with the following characteristics: values of 

specific conductance greater than 200 u.S/cm, a screened interval whose top is less than 20 m below land 

surface, concentrations of dissolved oxygen greater than 6 mg/L, the presence of pesticides in the ground 

water, a distance of less than 250 m between the wellhead and the surface-water divide, and presence of 

livestock near the wellhead. Ratios of stable isotopes of nitrogen in the water samples indicate that the 

source of nitrate in the ground water was predominantly chemical fertilizers rather than livestock wastes or 

effluent from septic systems.

Table 16. Capability of single variables to predict the relation of the concentration of nitrate in 

water from 12 shallow domestic wells in agricultural areas of the New Jersey Coastal Plain to the 

maximum contaminant level for nitrate

[<, less than; >, equal to or greater than; MCL, U.S. Environmental Protection Agency's Maximum 

Contaminant Level]

Percent correctly predicted

Variable

Variable-weighting 

or transformation method

Group 1 

(<MCL)

Group 2 Both 

(>MCL) groups

Water quality 

PH

Specific conductance 

Dissolved oxygen 

8N15 value 

Pesticides

Well-construction characteristics 

Depth of screened interval 

Top of screen ranked 

Bottom of screen ranked

ranked 

ranked 

ranked 

ranked 

present (1) or absent (2)

Hydrogeologic characteristics 

Hydrogeologic scenario

Distance to surface-water

divide

Distance to nearest stream

Land-use conditions 

Livestock 

Distance to septic tank

near (1) or downgradient (2) 

from the surface-water divide 

baselO log

base 10 log

present (1) or absent (2) 

base 10 log

54.5

95.5

50.0

78.6

72.7

68.2

81.8

63.6

50.0

50.0

86.4

63.6

62.5

95.5

56.5

83.3

75.0

70.8

70.8

50.0

50.0

50.0

50.0

66.7

58.7

95.5

53.3

81.3

73.9

69.6

76.1

54.2

50.0

50.0

67.4

65.2

35
Table 17. Capability of multiple variables to predict the relation of the concentration of nitrate in 

water from 12 shallow domestic wells in agricultural areas of the New Jersey Coastal Plain to the 

maximum contaminant level for nitrate

[<, less than; >, equal to or greater than; MCL, U.S. Environmental Protection Agency's Maximum 

Contaminant Level]

Percent correctly predicted

Discriminant 

analysis 

run number

1

2

3

4

Variables used in analysis

Specific conductance, depth to top of screen, 

presence of livestock

Specific conductance, presence of pesticides, 

presence of livestock, dissolved-oxygen 

concentration

Depth to top of screen, presence of pesticides, 

presence of livestock

Presence of pesticides, ratio of nitrogen isotopes,

Group 1 

(<MCL)

95.5

100

86.4

92.9

Group 2 

(>MCL)

91.7

100

100

83.3

Both 

groups

93.5

100

90.9

87.5

depth to bottom of screen

36
REFERENCES CITED

Anderson. J.R., Hardy, E.E., Roach, J.T., and Witmer, R.E., 1976, A land use and land cover classification 

system for use with remote sensor data: U.S. Geological Survey Professional Paper 964, 28 p.

Baker, D.B., 1990, Groundwater quality assessment through cooperative private well testing, an Ohio 

example: Journal of Soil and Water Conservation, v. 45, no. 2, p. 230-235.

Barringer, T., Dunn, D., Battaglin, W., and Vowinkel, E., 1990, Problems and methods involved in relating 

land use to ground-water quality: Water Resources Bulletin, v. 26, no. 1, p. 1-9.

Barton, G, Vowinkel, E.F., and Nawyn, J.P., 1987, Preliminary assessment of water quality and its relation 

to hydrogeology and land use: Potomac-Raritan-Magothy aquifer system, New Jersey: U.S. 

Geological Survey Water-Resources Investigations Report 87-4023, 79 p.

Cain, Doug, Helsel, D.R., and Ragone, R.E., 1989, Preliminary evaluations of regional ground-water 

quality in relation to land use: Ground Water, v. 27, no. 2, p. 230-244.

Eckel, J.A., and Walker, R.L., 1986, Water levels in major artesian aquifers of the New Jersey Coastal 

Plain, 1983: U.S. Geological Survey Water-Resources Investigations Report 86-4028, 62 p., 7 pi.

Fegeas, R.G., Claire, R.W, Guptil, S.C., Anderson, K.E., and Hallam, C.A., 1983, Land use and land cover 

digital data: U.S. Geological Survey Circular 895-E, 21 p.

Feltz, H.R., Anthony, E.R., and Sadler, Pamela, eds., 1984,1984 water quality laboratory services catalog: 

U.S. Geological Survey Open-File Report 83-758,118 p.

Fishman, M.J., and Friedman, L.C., 1985, Methods for determination of inorganic substances in water and 

fluvial sediments: U.S. Geological Survey Techniques of Water-Resources Investigations 

Report 85-495, book 5, chap. Al, 709 p.

Friedman, L.C., and Erdman, D.E., 1982, Quality assurance practices for the chemical and biological 

analyses of water and fluvial sediments: U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 5, chap. A6, 181 p.

Hamilton, PA., and Shedlock, R.J., 1992, Are fertilizers and pesticides in the ground water? A case study 

of the Delmarva Peninsula, Delaware, Maryland, and Virginia: U.S. Geological Survey Circular 

1080, 16 p.

Hantzsche, N.N., and Finnemore, E.J.,1992, Predicting ground-water nitrate-nitrogen impacts: Ground 

Water, v. 30, no. 4, July-August 1992, p. 490-499.

Heaton, T.H., 1986, Isotopic studies of nitrogen pollution in the hydrosphere and atmosphere: A review: 

Chemical Geology, v. 59, p. 87-102.

Helsel, D.R., 1987, Advantages of nonparametric procedures for analysis of water-quality data: Journal of 

Hydrological Sciences, v. 32, no. 2, p. 179-190.

37
REFERENCES CITED--Continued

Helsel, D.R., and Ragone, S.E., 1984, Evaluation of regional ground-water quality in relation to land use: 

U.S. Geological Survey Toxic Waste-Ground-Water Contamination Program: U.S. Geological 

Survey Water-Resources Investigations Report 84-4217, 33 p.

Johnson, R.L., 1980, Multivariate statistical analysis in geography: New York, Longman Scientific & 

Technical, John Wiley & Sons, 280 p.

Kammer, J.A., and Gibs, Jacob, 1989, An analytical technique for screening purgeable organic compounds 

in water: U.S. Geological Survey Open-File Report 89-53, 13 p.

Kish, G.R., Vowinkel, E.F., Fusillo, T.V., and Battaglin, W.A., 1988: Relation of land use to ground-water 

quality in the outcrop area of the Potomac-Raritan-Magothy aquifer system, New Jersey, in Moody, 

D.W, Carr, Jerry, Chase, E.B., and Paulson, R.W, compilers, National Water Summary 1986-- 

Hydrologic events and ground-water quality: U.S. Geological Survey Water-Supply Paper 2325, 

p. 109-114.

Kreitler, C.W, Ragone, S.E., and Katz, B.C., 1978, N15/N14 ratios of ground-water nitrate, Long Island, 

New York: Ground Water, v. 16, no. 6, p. 404-408.

Louis, J.B., Robson, M.G., and Hamilton, G.C., 1989, New Jersey pesticide use survey, in Weigman, D.L., 

ed., Pesticides in terrestrial and aquatic environments-Proceedings of the 1989 National Research 

Conference, May 11-12, 1989, Virginia Water Resources Research Center, Blacksburg, Virginia, 

p. 194-205.

Louis, J.B., and Vowinkel, E.F., 1989, Effect of agricultural chemicals on ground-water quality in the New 

Jersey Coastal Plain, in Weigman, D.L., ed., Pesticides in terrestrial and aquatic environmentsProceedings of the 1989 National Research Conference, May 11-12,1989, Virginia Water Resources 

Research Center, Blacksburg, Virginia, p. 80-89.

Martin, Mary, 1990, Ground-water flow in the New Jersey Coastal Plain: U.S. Geological Survey OpenFile Report 87-528, 182 p.

Murphy, E., 1992, Nitrate in drinking water wells in Burlington and Mercer Counties: Journal of Soil and 

Water Conservation, v. 47, no. 2, p. 183-187.

New Jersey Department of Agriculture, 1990, New Jersey agriculture 1990, annual report-Ag statistics: 

New Jersey Department of Agriculture Circular 526, 96 p.

New Jersey Department of Agriculture, 1980, New Jersey agricultural statistics 1980: New Jersey 

Department of Agriculture Circular 493, 61 p.

New Jersey Department of Agriculture, 1970, New Jersey agricultural statistics 1970: New Jersey 

Department of Agriculture Circular 458, 60 p.

New Jersey Department of Agriculture, 1961, New Jersey agricultural statistics 1961: New Jersey 

Department of Agriculture Circular 422, 72 p.

38
REFERENCES CITED-Continued

Peart, D.B., and Thomas, N.A., 1983, Quality-assurance data for routine water analysis in the laboratories 

of the U.S. Geological Survey for water year 1992: U.S. Geological Survey Water-Resources 

Investigations Report 83-4264, 38 p.

Tedrow, J.C., 1986, Soils of New Jersey: Malabar, Florida, Robert E. Krieger Publishing Company, 479 p.

U.S. Environmental Protection Agency, 1992, Another look: National survey of pesticides in drinking 

water wells, Phase II Report: EPA 570/9-91-020, 166 p.

U.S. Environmental Protection Agency, 1991, Fact sheet: National primary drinking-water standards: 

EPA 570/9-91-012FS. August 1991, 8 p.

U.S. Geological Survey, 1967, Engineering geology of the Northeast Corridor, Washington, D.C., to

Boston, Massachusetts: Coastal Plain and surficial deposits: U.S. Geological Survey Miscellaneous 

Geologic Investigations Map-I-514-B, 1 pi., 1:250:000 scale.

Vowinkel, E.F., and Battaglin, W.A., 1989, Methods of evaluating the relation of ground-water quality to 

land use in a New Jersey Coastal Plain aquifer system, in Mallard, G.E., and Ragone, S.E., eds., U.S. 

Geological Survey Toxic Substances Hydrology Program-Proceedings of the technical meeting, 

Phoenix, Ariz., September 26-30, 1988: U.S. Geological Survey Water-Resources Investigations 

Report 88-4220, p. 405-410.

Vowinkel, E.F., 1991, Comparison of relations between shallow-ground-water quality and land use in two 

New Jersey Coastal Plain aquifer systems, in Mallard, G.E., and Aronson, D.A., eds., U.S. 

Geological Survey Toxic Substances Hydrology Program-Proceedings of the technical meeting, 

Monterey, California, March 11-15, 1991: U.S. Geological Survey Water-Resources Investigations 

Report 91-4034, p. 307-313.

Vowinkel, E.F., and Foster, W.K., 1981, Hydrogeologic conditions in the Coastal Plain of New Jersey: 

U.S. Geological Survey Open-File Report 81-405, 39 p.

Walton, G., 1951, Survey of literature relating to infant methemoglobinemia due to nitrate-contaminated 

water: American Journal of Public Health, v. 41, p. 986-996.

Wershaw, R.L., Fishman, M.J., Grabbe, R.R., and Lowe, L.E., 1983, Methods for the determination of 

organic substances in water and fluvial sediments: U.S. Geological Survey Techniques of WaterResources Investigations Report 82-1004, book 5, chap. A3 , 173 p.

Wood, W.W., 1976, Guidelines for collection and field analysis of ground-water samples for selected 

unstable constituents: U.S. Geological Survey Techniques of Water-Resources Investigations, 

book l.chap. D2, 24 p.

Zapecza, O.S., 1989, Hydrogeologic framework of the New Jersey Coastal Plain: U.S. Geological Survey 

Professional Paper 1404-B, 49 p., 24 pi.

39
Appendix 1. Well-construction characteristics of 12 domestic wells in agricultural areas of the New Jersey Coastal Plain 

[--, information not available; Is, land surface; si, sea level; MM-DD-YY, month-day-year, min, minute]

New

Jersey

well 

number1

Date of

construction 

(MM-DD-YY)

Primary

use of 

water2

Altitude

of land

surface

above si 

(meters)

Depth to 

top of

open

interval

below Is 

(meters)

Depth to 

bottom

of open

interval

below Is 

(meters)

Discharge

rate 

(h'ters/min)

Date of 

discharge

and waterlevel

measurement 

(MM-DD-YY)

Depth to 

static

water

level

below Is 

(meters)

Depth to 

pumping

water

level

below Is 

(meters)

Aquifer 

code3

Potomac-Raritan-Magothv aquifer system

21-240

21-280

23-786

23-1010

23-1066

23-1069

10-03-76

11-20-79 

09-01-76 

01-25-85 

08-00-65

25.9

27.4

30.5

18.3

27.4

32.0

21.6

16.8

22.2

24.4

18.6

23.2

24.4

19.2

24.1

27.4

19.5

132

246

57

68

227

10-03-76

11-20-79 

09-01-67 

01-07-85 

08-00-65

10.7

2.1

2.1

13.7

4.0

16.8

16.7

18.3

7.6

211MRPAM

211MRPA

211MRPAM

211MRPAM

211MRPAM

211MRPAU

Kirkwood-Cohansey aquifer system

33-462

33-464

33-674

33-679

33-684

33-685

05-01-85

11-22-74

11-05-83

01-05-87

11-15-84

- -52

H

H

H

H

H

H

29.0

35.1

44.2

42.7

32.0

42.7

18.3

14.6

21.3

17.1

19.2

21.3

17.7

24.4

20.1

21.3

12.2

121CKKD

121CKKD

121CKKD

121CKKD

121CKKD

121CKKD

locations of wells shown in figure 5. The New Jersey well number consists of a two-digit county code followed by a consecutive number 

assigned to that well. The county codes are as follows: 21, Mercer, 23, Middlesex; and 33, Salem.

2H, domestic.

3Aquifer codes: 121CKKD, Cohansey Sand and Kirkwood Formation, undifferentiated; 

211MRPA, Potomac-Raritan-Magothy aquifer system, undifferentiated; 

211MRPAM, Potomac-Raritan-Magothy aquifer system, middle aquifer, 

211MRPAU, Potomac-Raritan-Magothy aquifer system, upper aquifer.

40
Appendix 2. Results of water-quality analyses of samples from 12 domestic wells in agricultural areas of the New Jersey 

Coastal Plain

A. Physical characteristics and chemical constituents measured in the field

[MM-DD-YY, month-day-year, <, less than; °C, degrees Celsius; mg/L, milligrams per liter, ^S/cm, microsiemens per 

centimeter at 25 degress Celsius; -- analysis not performed; CaCQj, calcium carbonate]

New 

Jersey 

well 

number

Date 

sampled 

(MM-DD-YY)

Air 

temperature 

(°Q

Water 

temperature 

(°C)

PH 

(standard 

units)

Alkalinity 

(mg/L 

as CaCO3)

Specific 

conductance 

(uS/cm)

Dissolved 

oxygen 

(mg/L)

Pototnac-Raritan-Magothv aquifer system

21-240

21-280

23-786

23-1010

23-1066

23-1069

05-01-91

08-13-91

12-19-91

02-11-92

04-30-91

09-05-91

12-17-91

03-10-92

05-01-91

08-14-91

12-19-91

03-11-92

04-30-91

08-15-91

12-16-91

03-10-92

05-02-91

08-15-91

12-16-91

03-11-92

05-08-91

08-13-91

12-17-91

02-11-92

24.5

28.0

-5.0

8.0

24.0

22.0

-3.0

-

23.0

28.0

0.0

~

16.0

25.0

-1.0

~

17.0

27.0

-2.0

~

19.0

30.5

-6.0

-

12.6

12.9

11.2

11.2

12.6

12.6

12.0

12.2

13.1

13.5

12.3

12.6

12.2

13.0

12.3

12.5

12.3

13.5

11.7

11.5

12.8

13.3

11.9

11.8

5.5

5.5

5.5

5.7

5.5

4.8

5.5

5.3

5.0

5.0

5.0

4.9

7.9

7.8

7.7

7.8

5.4

5.4

5.5

5.3

5.1

5.0

5.1

5.3

6

6

10

10

9

14

10

3

2

-

69

68

64

72

3

4

12

-

3

2

2

6

163

214

176

162

268

264

273

260

162

200

164

155

158

164

165

153

152

162

170

161

360

463

371

390

8.9

9.7

9.3

8.7

6.9

7.3

7.6

7.2

8.6

8.8

9.4

8.7

0.2

.2

.1

.1

9.1

8.8

9.5

9.1

8.3

8.6

8.6

8.8

Kirkwood-Cohansgy aquifer system

33-462

33-464

33-674

33-679

33-684

33-685

04-24-91

08-22-91

12-23-91

02-19-92

04-24-91

09-04-91

12-09-91

02-19-92

04-26-91

08-21-91

12-12-91

04-23-91

08-21-91

12-12-91

02-20-92

04-21-92

04-26-91

08-22-91

12-10-91

04-21-92

04-23-91

08-20-91

12-09-91

02-20-92

04-21-92

22.0

~

-

-

13.8

-

20.0

-

27.0

-

23.0

-

14.5

-

23.5

31.0

13.5

-

20.5

-

-

9.0

-

13.8

14.0

12.9

13.9

13.8

13.7

13.7

13.2

14.2

13.8

12.6

13.7

12.8

13.0

13.0

13.7

14.2

14.9

13.0

13.6

13.9

14.3

14.6

13.7

14.0

4.5

4.5

4.5

4.5

5.2

4.5

5.1

5.1

4.6

4.6

4.6

4.9

4.9

5.0

5.0

5.0

4.4

4.4

4.4

4.5

5.7

5.7

5.8

5.8

5.9

<1

<1

<1

<1

3

<1

-

<1

<1

<1

2

~

<1

<1

<1

<1

11

13

47

62

61

53

218

220

210

203

163

176

164

412

418

396

415

406

222

211

197

187

377

348

335

317

287

.3

.2

.2

.1

9.0

9.8

10.2

9.3

5.9

6.7

6.3

9.1

10.6

9.7

9.0

9.2

10.3

10.1

-

8.0

9.0

8.3

7.7

41
Appendix 2. Results of water-quality analyses of samples from 12 domestic wells in agricultural areas of the New Jersey

Coastal Plain 

B. Dissolved major ions

[All concentrations in milligrams oer liter: <,

New

Jersey 

well 

number

Date 

sampled 

(MM-DD-YY)

Dissolved 

solids Calcium Magnesium

. less than

Sodium

: MM-DD-YY month-dav-vearl

Constituent

Potassium Silica Chloride Sulfate Fluoride

Potomac-Raritan-Magothy aquifer system

21-240

21-280

23-786

23-1010

23-1066

23-1069

05-01-91

04-30-91

05-01-91

04-30-91

05-02-91

05-08-91

117

111

113

113

82

167

12

23

11

14

9.9

23

2.8

8

4.1

3.3

3.4

15

9.8

8.4

6

11

10

7.8

2.7

3.2

2.8

2.0

2.2

7.9

14

16

9.1

43

15

11

19

26

21

5.4

17

26

0.2 <0.1

16 <.l

.2 <.l

2.7 .2

.2 <.l

38 <.l

Kirkwood-Cohansey aquifer system

33-462

33-464

33-674

33-679

33-684

33-685

04-24-91

04-24-91

04-26-91

04-23-91

04-26-91

04-23-91

44

109

84

220

133

238

.74

8.4

9.3

32

16

28

.49

13

3.7

20

5.2

24

2

3.1

7.6

4.7

2.8

5.9

1.1

3.3

1.5

1.6

3.6

2.0

18

9.5

12

12

7

10

<.l

22

20

18

21

26

9.5 <.l

3.3 <.l

7.8 <.l

62 <.l

.5 <.l

80 <.l

42
C. Dissolved trace elements

[All concentrations in micrograms per liter; <, less than; MM-DD-YY, month-day-year]

Constituent

New

Jersey Date 

well sampled Beryl- Cad- Chronumber (MM-DD-YY) Arsenic Barium lium Boron mium mium Cobalt Copper Iron

21-240 05-01-91 <1 180

21-280 04-30-91 <1 320

23-786 05-01-91 <1 250

23-1010 04-30-91 <1 48

23-1066 05-02-91 <1 19

23-1069 05-08-91 <1 65

33-462 04-24-91 <1 15

33-464 04-24-91 <1 100

33-674 04-26-91 <1 52

33-679 04-23-91 <1 61

33-684 04-26-91 <1 110

33-685 04-23-91 <1 47

Potomac-Raritan-Magothv aquifer system

0.6 <10 <1 <5 <3 20 12

<.5 <10 <1 <5 <3 20 13

.6 <10 2 <5 <3 20 <3

<.5 50 <1 <5 <3 <10 410

<.5 <10 <1 <5 <3 40 <3

3 <10 1 <5 10 130 150

Kirkwood-Cohansev aauifer system

<.5 <10 <1 <5 <3 <10 780

<5 20 <1 <5 6 60 18

<.5 <10 <1 <5 3 30 210

<.5 10 <1 <5 <3 20 41

1 10 <1 <5 7 20 8

<.5 10 <1 <5 <3 <10 6

Lead

2

3

1

<1

3

9

^

3

1

7

3

2

Constituent

New

Jersey Date 

well sampled 

number (MM-DD-YY) Lithium

21-240 05-01-91 <4

21-280 04-30-91 <4

23-786 05-01-91 <4

23-1010 04-30-91 4

23-1066 05-02-91 <4

23-1069 05-08-91 4

33-462 04-24-91 <4

30-464 04-24-91 <4

33-674 04-26-91 <4

33-679 04-23-91 <4

33-684 04-26-91 <4

33-685 04-23-91 <4

Manga- Molyb- Stron- Vananese Mercury denum Nickel Silver tium dium

Potomac-Raritan-Magotfav aquifer system

9 0.1 <10 <10 <1 160 <6

19 .2 <10 <10 <1 350 <6

18 .3 <10 <10 <1 130 <6

280 .2 <10 <10 <1 140 <6

7 .1 <10 <10 <1 130 <6

310 .2 <10 <10 <1 210 <6

Kirkwood-Cohansey aquifer system

9 .2 <10 <10 <1 8 <6

19 .2 <10 <10 <1 140 <6

15 .2 <10 <10 <1 26 <6

20 .3 <10 <10 <1 200 <6

36 .2 <10 <10 <1 62 <6

54 .2 <10 <10 <1 290 <6

Zinc

12

26

23

4

12

60

16

5

42

31

12

26

43
Appendix 2. Results of water-quality analyses of samples from 12 domestic wells in agricultural areas of the New 

Jersey Coastal Plain

D. Dissolved nutrients and nitrogen isotope ratios

[All concentrations in milligrams per liter, except where noted; <, less than; --, no sample collected; MM-DD-YY, month-day-year]

Constituent

New 

Jersey 

well 

number

Date 

sampled 

(MM-DD-YY)

Ammonia 

as 

nitrogen

Ammonia 

Nitrite plus organic 

as nitrogen 

nitrogen as nitrogen

Nitrite 

plus 

nitrate 

as nitrogen

Nitrogen15/14 

isotope ratio 

Ortho- (dn15 , 

phosphate in per mil)

Potomac-Raritan-Magothy aquifer system

21-240

21-280

23-786

23-1010

23-1066

23-1069

05-01-91

08-13-91

12-19-91

02-11-92

04-30-91

09-05-91

12-17-91

03-10-92

05-01-91

08-14-91

12-19-91

03-11-92

04-30-91

08-15-91

12-16-91

03-10-92

05-02-91

08-15-91

12-16-91

03-11-92

05-08-91

08-13-91

12-17-91

02-11-92

<0.01

.01

.01

<.01

_

<.01

<.01

.02

<.01

<.01

.02

_

.52

.53

.52

<.01

.02

<.01

.02

<.01

<.01

<.01

<.01

<0.01 0.4

<.01 .6

<.01 <.2

<.01 <.2

_

<.01 .7

 cOl <.2

<.01 <.2

<.01 .4

..

<.01 <.2

<.01 <.2

__

<.01 .6

<.01 .5

<.01 .5

<.01 .5

<.01 .5

<.01 <.2

<.01 <.2

<.01 .8

<.01 .7

.01 <.2

<.01 <.2

9.5

9.7

9.3

9.2

_

13

13

13

8.5

8.3

8.2

_

<.05

.06

<.05

8.7

9.2

9.2

9.3

17

20

21

22

<0.01 2.6

<.01 2.7

<.01 1.7

<.01

6.3

<.01 5.5

.01 5.8

<.01

<.01 3.7

3.3

<.01 2.4

<.01

3.0

.08 2.0

.08 1.4

.08

<.01 2.6

<.01 2.5

.01 2.0

<.01

<.01 3.7

<.01 4.7

.01 3.5

<.01

Kirkwood-Cohansey aquifer system

33-462

33-464

33-674

33-679

33-684

33-685

04-24-91

08-22-91

12-23-91

02-19-92

04-24-91

09-04-91

12-09-91

02-19-92

04-26-91

08-21-91

12-12-91

04-23-91

08-21-91

12-12-91

02-20-92

04-21-92

04-26-91

08-22-91

12-10-91

04-21-92

04-23-91

08-20-91

12-09-91

02-20-92

04-21-92

.03

<.01

.02

<.01

.02

<.01

<.01

.01

<.01

<.01

.02

<.01

<.01

.02

.01

<.01

<.01

<.01

.01

<.01

<.01

.04

<.01

.021

<.01

.05 <.2

<.01 <.2

 cOl <.2

<.01 <.2

.06 .4

<.01 .5

 cOl <.2

<.01 <.2

<.01 1

<.01 .6

<.01 <.2

<01 .6

<.01 .6

.01 <.2

<.01 <.2

<.01 <.2

<.01 .7

<.01 .7

<.01 <.2

<.01 <.2

<.01 .4

<01 .6

<.01 <.2

<.01 <.2

<.01 <.2

.09

<.05

<.05

<.05

12

12

12

12

7.5

8.0

7.9

16

14

14

14

14

14

15

14

14

13

15

15

14

13

<.01

<.01

.01

<.01

<.01 2.6

<.01 1.9

<.01 1.6

<.01

<.01 3.6

<.01 3.2

<.01 2.9

<.01 4.4

<.01 3.8

<.01 3.7

<.01

<.01

<.01 4.0

<.01 3.9

<.01 3.1

<.01

<.01 4.2

<.01 3.3

<.01 3.5

<.01

<.01

44
E Dissolved organic carbon, methylene blue active substances fecal coliform. and fecal streptococci

[mg/L, milligrams per liter, mL, milliters; <, less than; K, nonideal colony count; , no sample collected; MM-DD-YY, month-day-year]

New 

Jersey 

well 

number

21-240

21-280

23-786

23-1010

23-1066

23-1069

33-462

33-464

33-674

33-679

33-684

33-685

Date 

sampled 

(MM-DD-YY)

05-01-91 

08-13-91 

12-19-91 

02-11-92

04-30-91 

09-05-91 

12-17-91 

03-10-92

05-01-91 

08-14-91 

12-19-91 

03-11-92

04-30-91 

08-15-91 

12-16-91 

03-10-92

05-02-91 

08-15-91 

12-16-91 

03-11-92

05-08-91 

08-13-91 

12-17-91 

02-11-92

04-24-91 

08-22-91 

12-23-91 

02-19-92

04-24-91 

09-04-91 

12-09-91 

02-19-92

04-26-91 

08-21-91 

12-12-91

04-23-91 

08-21-91 

12-12-91 

02-20-92 

04-21-92

04-26-91 

08-22-91 

12-10-91 

04-21-92

04-23-91 

08-20-91 

12-09-91 

02-20-92 

04-21-92

Constituent

Dissolved Methylene Fecal 

organic blue active coliform 

carbon substances (colonies 

(mg/L) (mg/L) per 100 mL)

Potomac-Raritan-Magothy aquifer system 

0.2 0.08 <1 

.08 <1 

.09 <1

.6 .12 <1 

.11 <1 

.14 <1

.3 .08 <1 

.06 <1 

.11 <1

.3 .01 <1 

.01 <1

.2 .08 <1 

.08 <1 

.09 <1

.8 .16 <1 

.16 <1 

.18 <1 

IK

Kirkwood-Cohansey aquifer system 

.3 <.01 <1 

.01 <1

.11 3K 

.11 <1 

.12 <1

.3 .07 <1 

.13 <1 

.14 <1

.8 .12 <1 

.14 <1 

.08 <1

.4 .14 <1 

.13 <1 

.14 <1

.8 .10 <1 

.15 <1 

.14 2K

Fecal 

streptococci 

(colonies 

per 100 mL)

3K 

IK

41 

76 K 

20 K

9K

38

IK

15 K 

IK

6K 

IK

3K 

3K

IK 

81 K 

16K

6K 

37 K

2K

54

28 K 

110 

36

3K

45
Appendi 2. Results of water-quality analyses of samples from 12 domestic wells in agricultural areas of the New Jersey Coastal Plain 

F. Total triazine and acetanilide herbicides

[All concentrations in micrograms per liter, <, less than; MM-DD-YY, month-day-year]

New 

Jersey 

well 

number

Triazine herbicides

Date 

sampled 

(MM-DD-YY)

Ametryne

Alra- Atrazine, 

zine desethyl

Atrazine, 

deiso- Cyanapropyl zine

PrometonePrometryne

PropaazineSimazine

Acetenilide herbicides

AlachlorMetolachlorMetribuzin

Potomac-Raritan-Maeothv aauifer system

21-240

21-280

23-786

23-1010

23-1066

23-1069

05-01-91 

08-13-91 

12-19-91

04-30-91 

09-05-91 

12-17-91

05-01-91 

08-14-91 

12-19-91

04-30-91 

08-15-91 

12-16-91

05-02-91 

08-15-91 

12-16-91

05-08-91 

08-13-91 

12-17-91

<0.05 

<.05 

<.05

<.05 

<.05 

.5

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<0.05 <0.05 

<.05 <.05 

<.05 <.05

<.05 <.05 

<.05 <.05 

<.05 <.05

<.05 <.05 

<.05 <.05 

<.05 <.05

<.05 <.05 

<.05 <.05 

<.05 <.05

<.05 <.05 

<.05 <.05 

<.05 <.05

<.05 .08 

<.05 <.05 

<.05 <.05

<0.05 <0.2 

 COS <.2 

<.05 <.2

<.05 <.2 

<.05 <.2 

<.05 <.2

<.05 <.2 

<.OS <.2 

<.05 <.2

c05 <.2 

c05 <.2 

c05 <.2

<.05 <.2 

<.05 <.2 

<.05 <.2

c05 <.2 

c05 <.2 

c05 <.2

<0.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<0.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<0.05 

<.05 

<.05

<-05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<0.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<0.05 

<05 

<.05

8.8 

8.0 

8.0

<.05 

c05 

<.05

c05 

<.05 

<.05

<.05 

<.05 

c05

<.05 

<.05 

.14

<0.05 

<.05 

.09

<.05 

<.05 

<.05

<.05 

<-05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

.25 

.19 

.17

<0.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

.22 

<.05 

.08

Kirkwood-Cohansey aquifer systern

33-462

33-464

33-674

33-679

33-684

33-685

04-24-91 

8-22-91 

12-23-91

04-24-91 

09-04-91 

12-09-91

04-26-91 

08-21-91 

12-12-91

04-23-91 

08-21-91 

12-12-91

04-26-91 

08-22-91 

12-10-91

04-23-91 

08-20-91 

12-09-91

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 <.05 

<.05 <.05 

<.05 <.05

<.05 <.05 

<.05 <.05 

<.05 <.05

<.05 <.05 

<.05 <.05 

<.05 <.05

<.05 .20 

<.05 <.05 

<.05 .22

<.05 <.05 

<.05 <.05 

<.05 <.05

.44 .19 

<.05 <.05 

.54 .46

<.05 <.2 

<05 <.2 

<05 <.2

<.05 <.2 

c05 <.2 

<.05 <.2

c05 <.2 

c05 <2 

c05 <.2

c05 <.2 

c05 <.2 

c05 <.2

c05 <.2 

<05 <.2 

<05 <.2

.48 <.2 

c05 <.2 

.92 <.2

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

c05 

c05 

c05

<.05 

c05 

c05

<.05 

c05 

c05

c05 

<05 

<.05

<.05 

<05 

<.05

.07 

.18 

.18

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

.09

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<.05 

<.05 

<-05

<.05 

<.05 

<.05

<.05 

<.05 

<.05

<-05 

<.05 

<.05

46
Appendix 2. Results of water-quality analyses of samples from 12 domestic wells in agricultural areas of the New Jersey Coastal Plain 

G. Total carbamate insecticides 

[All concentrations in micrograms per liter, <, less than; MM-DD-YY, month-day-year]

New 

Jersey 

well 

number

21-240

21-280

23-786

23-1010

23-1066

23-1069

33-462

33-464

33-674

33-679

33-684

33-685

Insecticide

Aldi- Aldi- 3- 

Date carb carb hydroxy 

sampled Aldi- aul- sulfox- Carb- Carbo- carbo- Metho- 1-Naph- 

(MM-DD-YY) carb phone ide ayl furan furan myl thol Oxymyl Propham

Potomac-Raritan-Magothy aquifer system

05-01-91 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5

08-13-91 <-5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-19-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

04-30-91 <.5 <.5 <.5 <.5 1.5 <.5 2.1 <.5 <.5 <.5

09-05-91 <.5 <.5 <.5 <.5 2.1 <.5 4.2 <.5 <.5 <.5

12-17-91 <.5 <.5 <.5 <.5 5.8 <.5 5.6 <-5 <.5 <.5

05-01-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <5 <.5 <.5

08-14-91 <-5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-19-91 <-5 <.5 <.5 <.5 <.5 <.5 <.5 <5 <.5 <.5

04-30-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

08-15-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-16-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

05-02-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

08-15-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-16-91 <5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

05-08-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

08-13-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-17 91 <.5 .5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

Kirky wd'Cohansey aquifer system

04-24-91 ^.5 ^5 ^5 ^5 ^5 ^5 ^5 ^.5 ^5 ^5

08-22-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-23-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

04-24-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

09-04-91 <5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-09-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <-5 <.5 <.5

04-26-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <-5 <.5 <.5

08-21-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-12-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

04-23-91 <-5 <.5 <.5 <.5 1.8 <.5 <.5 <.5 <.5 <.5

08-21-91 <.5 <.5 <.5 <.5 2.6 <.5 <.5 <-5 <.5 <.5

12-12-91 <.5 <.5 <.5 <.5 2.1 <.5 <.5 <.5 <.5 <.5

04-26-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

08-22-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-10-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <5 <.5 <.5

04-23-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

08-20-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

12-09-91 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5 <.5

47
Appendix 2. Results of water-quality analyses of samples from 12 domestic wells in agricultural areas of the New Jersey Coastal Plain

H. Volatile organic compounds

[All concentrations in micrograms per liter, <, less than; MM-DD-YY, month-day-year]

New 

Jersey

well

number

21-240

21-280

23-786

23-1010

23-1066

23-1069

33-462

33-464

33-674

33-679

33-684

33-685

Date

sampled

(MM-DD-YY) Benzene

05-01-91 <0.2

04-30-91 <.2

05-01-91 <.2

04-30-91 <2

05-02-91 <2

05-08-91 <-2

04-24-91 <.2

04-24-91 <.2

04-26-91 <.2

04-23-91 <.2

04-26-91 <.2

04-23-91 <.2

Carbon- 2-Chloro- Ditetra- Bromodi- ethyl- bromoBromo- Bromo- chlo- Chloro- chloro- Chloro- vinyl- Chloro- chloroform methane ride benzene methane ethane ether form methane

Potomac-Raritan-Magothv aquifer svstem

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

Kirkwood-Cohansev aquifer svstem

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <2 <.2 <.2 <.2 <2

<.2 <.2 <.2 <.2 <2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <2 <.2 <.2 <.2 <2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

1,1-Dichloroethene

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

New

Jersey

well

number

21-240

21-280

23-786

23-1010

23-1066

23-1069

33-462

33-464

33-674

33-679

33-684

33-685

Date 1,2-Disampled chloro-

(MM-DD-YY) ethane

05-01-91 <0.2

04-30-91 <.2

05-01-91 <.2

04-30-91 <.2

05-02-91 <.2

05-08-91 <.2

04-24-91 <.2

04-24-91 <.2

04-26-91 <.2

04-23-91 <.2

04-26-91 <.2

04-23-91 <.2

New Date

Jersey sampled

well (MM-DDnumber YY)

21-240 05-01-91

21-280 04-30-91

23-786 05-01-91

23-1010 04-30-91

23-1066 05-02-91

23-1069 05-08-91

33-462 04-24-91

33-464 04-24-91

33-674 04-26-91

33-679 04-23-91

33-684 04-26-91

33-685 04-23-91

cis- trans- trans- Methyl- 1,1,2,2-

1,1-Di- 1,2-Di- 1,2-Di- 1,2-Di- 1,3-Di- ene Tetrachloro- chloro- chloro- Chloro- chloro- chloro- Ethyl- chlo- chloroethylene ethylene ethyene methane propane propene benzene ride ethane

Potomac-Raritan-Magothv aquifer system

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <2 <.2 <.2 <.2 <.2 <.2

Kirkwood-Cohansev aquifer svstem

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <2 <.2 <.2 <.2 <.2 <.2

1,1,1- 1,1,2- cis transTri- Tri- Vinyl 1,2-Di- 1,3-Di- 1,4-Di- 1,3-Di- 1,3-Dichloro- chloro- chlo- chloro- chloro- chloro- chloro- chloroToluene ethane ethane ride benzene benzene propene propene propene

Potomac-Raritan-Magothv aquifer system

<0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2

<.2 <.2 <.2 <.2 <.2 <2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

Kirkwood-Cohansey aquifer system

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

<.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2 <.2

Tetrachloroethylene

<0.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

<.2

48