EPA 560/3-75-006
                                   THE  IMPACT  OF  INTENSIVE
                                  APPLICATION  OF  PESTICIDES
                               AND FERTILIZERS ON UNDERGROUND
                                    WATER RECHARGE AREAS
                                   WHICH MAY CONTRIBUTE TO
                                   DRINKING WATER SUPPLIES
                                    A Preliminary Review
                                 Office of Toxic Substances
                            U.S. Environmental Protection Agency
                                   Washington, D.C.  20460
                                        January 1976

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Document is available to the public through the National
Technical Information Service, Springfield, Virginia  22151.

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EPA 560/3-75-006
                            THE IMPACT  OF  INTENSIVE
                           APPLICATION  OF  PESTICIDES
                        AND FERTILIZERS ON UNDERGROUND
                             WATER RECHARGE AREAS
                            WHICH MAY CONTRIBUTE TO
                            DRINKING WATER SUPPLIES
                            A Preliminary Review
                          Office of Toxic Substances
                     U.S. Environmental Protection Agency
                            Washington, D.C.  20460
                                  January 1976

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               PREFACE
This report is an initial technical review
of some of the problems which may be posed
by pesticides and fertilizers to drinking
water supplies.  Prepared for the Office
of Toxic Substances by Ecosystems Incor-
porated, this final version incorporates
some revisions made by the Special Projects
Branch of the Office of Toxic Substances
under the guidance of David Garrett,
Chief of that Branch.

This report has been reviewed by the Office
of Toxic Substances, EPA, and approved for
publication.  Approval does not signify
that the contents necessarily reflect
the views and policies of the Environmental
Protection Agency, nor does mention of
trade names or commercial products consti-
tute endorsement or recommendation for use.

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                        TABLE OF CONTENTS



SECTION 1 - AN INITIAL ASSESSMENT                                1

     I.   SUMMARY                                                1

    II.   GROUNDWATER RECHARGE AND TOXIFICATION FROM
          AGRICULTURAL SOURCES                                   3

          A.   Introduction and Overview                         3
          B.   Types of Contaminants                             5
          C.   Movement of Waste Fluids     .                     6
          D.   Control and Removal of Contaminants               7
          E.   Monitoring Groundwater Quality                    8
          F.   Sources of Information                            9
          G.   Groundwater Assessment                           20

   III.   NITRATES                                              21

          A.   Nitrogen Cycle                                   21
          B.   Health Effects of Nitrate                        26
          C.   Fertilizers                                      27
          D.   Feedlots                                         30
          E.   Septic Tank Systems (On Site Domestic
               Waste Disposal)                                  38

    IV.   AGRICULTURAL PESTICIDES                               39

          A.   Introduction and Overview                        39
          B.   Preliminary Correlation Between Organics
               Found in Drinking Water and Specific
               Pesticide and Fertilizer Uses                    44
          C.   Laboratory Testing Procedures for
               Pesticides                                       50

     V.   ECONOMIC IMPACT OF GROUNDWATER CONTAMINATION
          ABATEMENT                                             52

          A.   Introduction and Overview                        52
          B.   Cost-Benefit Analysis                            52
          C.   Intangible Benefits                              53
          D.   Economic Impact Analysis                         54

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          E.   Primary Costs                                     55
          F.   Secondary Costs                                   55

    VI.   GROUNDWATER FLOW MODELS                                56

          A.   Introduction and Overview                         56
          B.   Unsaturated Flow                                  57
          C.   Saturated Zone                                    57
          D.   Dispersion With No Adsorption                     59
          E.   Dispersion With Adsorption                        59
          F.   Summary of Dispersion Models                      60
          G.   Regional Models                                   60

SECTION 2 - A PROGRAM PLAN FOR MORE DETAILED INVESTIGATION       66

     I.   INTRODUCTION                   .                        66

    II.   GENERAL                                                67

          A.   Task G-l                                          67
          B.   Task G-2                  .         .               69
          C.   Task G-3                                          69
          D.   Task G-4                                         . 70

   III.   NITRATES              •    .  .      .                     70

          A.   Fertilizers                                       70

               1.   Task FR-1                      .              70
               2.   Task FR-2                  -                  72

          B.   Feedlots                           -              75

               1.   Task FE-1                                    75
               2.   Task FE-2                                    76
               3.   Task FE-3                 .   .                79

          C.   Septic Systems and Groundwater                    80

               1.   Task S-l                                     80

    IV.   PESTICIDES                    .           ,              81

          A.   Task P-l                                          81

     V.   ECONOMIC IMPACT OF MEASURES TAKEN TO REMEDY  ,
          GROUNDWATER CONTAMINATION                              83

          A.   Introduction and Overview     .                    83

                              ii            •

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          B.   Task E-l:  Choose Alternative Remedies            86
          C.   Task E-2:  Determine Primary Industry Effects     87
          D.   Task E-3:  Determine Secondary Effects            89

    VI.   Modeling                                               90

          A.   Task M-l                                          90

SECTION 3 - BIBLIOGRAPHY                                         93
                              111

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                         LIST OF FIGURES
FIGURE                                                           PAGE


l-II-l    Groundwater withdrawn, by regions, 1970 in            -
          million gallons a day                                  10

1-II-2    General Map Showing Annual Runoff and
          Productive Aquifers in the Conterminous United
          States                                                 12

1-II-3    Crop Producing Regions                                 13

1-II-4    Precipitation Map of the Conterminous United
          States                                                 15

1-II-5    "Precipitation Retained" Map of the
          Conterminous United States                            16

1-II-6    Farm Production Regions                                17

1-II-7    Fertilizer-Consuming Regions in the United
          States                                                 18

l-III-l   Major Phases of the Nitrogen Cycle                     23

1-III-2   Cattle Feeding Area                                    36

1-III-3   Feed Cattle Marketed in 23 Major States                37

2-1-1     Activity Streams                                       68

2-V-l     Flow Diagram of Economic Impact Analysis               85
                                 iv

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                         LIST OF TABLES
TABLE                                                       PAGE

l-III-l   Production of Wastes by Livestock in the
          United States                                      31

1-III-2   Population Equivalent of the Fecal Production
          by Animals, in Terms of Biochemical Oxygen
          Demand (BOD)                                       32

1-III-3   Average Daily Manure Production and Compo-
          sition                                             33

1-IV-l    Organic Compounds Identified in Drinking Water*    45,6,7

l-IV-2    Pesticide Chemicals Identified in Drinking
          Water Active Ingredients                           48

l-IV-3    Non-Active Ingredients of Pesticide
          Formulations Identified in Drinking Water          49
                                 v

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                      THE IMPACT OF INTENSIVE
                     APPLICATION OF PESTICIDES
                  AND FERTILIZERS ON UNDERGROUND
                       WATER RECHARGE AREAS
                      WHICH MAY CONTRIBUTE TO
                      DRINKING WATER SUPPLIES
                             Section 1
                       An Initial Assessment
I.   SUMMARY
     This report presents an Assessment of the impact of intensive
     application of pesticides and fertilizers on underground water
     recharge areas which may contribute to drinking water supplies; and
     also presents a Plan for developing additional information required
     to define the nature and extent of the impact of agricultural
     practices on groundwater supplies for public water systems, as
     required by the Safe Drinking Water Act (PL-93-523).

     In the perspective of what additional information is needed to
     determine the time extent of agricultural impacts on underground
     water recharge, the operation of feedlots represents a significant
     concern.  Special emphasis is therefore placed on this subject.
     Feedlots, in addition to being a most concentrated source of po-
     tential pollution, may also offer the greatest range of choices for
     abatement, some of which might even be economically profitable.

     Pesticides appear to offer only a marginal threat to groundwater
     because of their adsorptive properties on soil structure and/or
     their short-lived persistence.  The exception to this statement
     might be where pesticides are improperly applied, or there exist
     sandy soils or thin soils overlaying fissured rocks.  Groundwater
     recharge, from streams and lakes polluted with pesticide-contami-
     nated runoff has not been considered to fall within the scope of
     the present study even though such runoff originated from agri-
     cultural areas.  Pesticide pollution from "home garden" appli-
     cations may also represent a genuine problem in terms of use by
     unqualified persons and improper disposition of residues, con-
     tainers and excess supplies, but is defined as being outside the
     scope of the present study.

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Fertilizers are usually applied at rates designed to yield a
maximum agronomic return for the quantities of fertilizers applied,
but this is often done on a "rule of thumb" basis.  The application
rates, methods and associated tillage practices have generally been
established without regard to groundwater quality.  Surface water
runoff considerations have usually been assigned a greater impor-
tance.  More information is required as to how much nitrate is
reaching groundwater because the total annual fertilizers require-
ment was applied in one or two heavy treatments, rather than ligh-
ter applications made several times during the growing season.

Septic tanks on farms present an insignificant source of pollution
to groundwater as related to public drinking water supplies. How-
ever, the well water supply on that particular farm may be sus-
ceptible.  Often the design, construction, or maintenance of a
septic system or a water well has been inadequate to protect against
contamination.  On the other hand, cesspools are considered to have
a higher pollution potential to groundwater because essentially raw
sewage may move directly to the groundwaters.

Cesspool installations are now widely prohibited, however, and even
though thousands are still in use, it is not deemed necessary to
investigate this problem further.

There is a need for greater knowledge of the process of nitri-
fication and denitrification in various soils and subsoils as a
function of soil temperature, climate, and biochemistry.  Such
studies are needed for both animal waste applications, and for
fertilizer and crop cover sources of nitrogen.  With regard to
possible changes in law dealing with agricultural practices to
protect groundwater from toxification it is recognized that impacts
on the farmer could be dominant.  Not all these effects are ex-
pected to be detrimental; in fact, some changes may, in the long
run, contribute to increased productivity of the land.

Consideration is given to the geologic, edaphic, climatologic, and
hydrologic aspects of the problem.  In addition, the economic
impact of modification of agronomic practices is taken into ac-
count.  It is to be hoped that the cost of abatement measures may
be offset, at least in some instances, by the opportunity for waste
recovery as fertilizer or fuel.

The findings of the studies on the intrusion of toxic substances
into groundwater recharge areas, whether from nitrates or pesti-
cides, ought to be modeled to provide predictions of future con-
sequences as a result of the continued use of these substances.
Modeling will also permit parameters to be varied so as to deter-
mine the application levels at which these substances would no
longer toxify the groundwater.

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     The Plan for the future work consists of a series of tasks designed
     to fill the gaps in current knowledge of the degree—and by what
     mechanisms—groundwater becomes polluted from agricultural prac-
     tices,  and to provide information important for pollution abatement
     and control.  The tasks are grouped under four major headings:  (a)
     Nitrates; (b) Pesticides; (c) Economic Impacts; and (d) Modeling
     and Simulation.   Under the heading of Nitrates, sub-tasks deal with
     feedlots, fertilizers, septic tanks and problems which relate to
     several nitrate sources.

II.   GROUNDWATER RECHARGE AND TOXIFICATION FROM AGRICULTURAL SOURCES

     A.   Introduction and Overview

          This report has been prepared to help  identify  program ele-
          ments required to determine the nature and extent of the
          impact from agricultural practices on groundwater supplies to
          public water systems, as stated in the Safe Drinking Water Act
          (PL-93-523).

          About 97 percent of the earth's fluid fresh water is ground-
          water.  This groundwater is used as a water supply by about
          two-thirds of the people in the United States  [62].  To pre-
          serve this most valuable natural resource, a national program
          of groundwater quality protection and restoration is a neces-
          sity.  A major need in developing such a program is a defini-
          tion of groundwater pollution problems and potential problems
          and the scope and significance of each.  To determine the
          extent of these problems the Office of Research and Develop-
          ment of the U.S. Environmental Protection Agency has initiated
          a program to assess groundwater pollution problems throughout
          the United States.  Studies have been completed for Arizona,
          California, Nevada, and Utah  [26], the South Central States
          [62], the Northeastern States  [86], and the Northwestern
          States  [95].  The studies for the other regions of the country
          are at various stages of preparation.  These reports will
          cover the Southeast States  (report due March 1976),  the Mid-
          West States (October 1976), East  (March 1977), and Hawaii  and
          Alaska  (March 1977)  [100].

          Groundwater is a most important asset in  this  country in terms
          of  its freshness, usefulness  in quality,  and in general,
          quantity.  Even  though groundwater comprises at least 95 per-
          cent of the nation's freshwater reserves, only about 20  per-  ,
          cent of the total  quantity  of water now used in the  United
          States  is supplied  from underground sources  [94].

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Groundwater collection into aquifers is a direct result of
seepage of surface water through percolation, seepage through
cracks in underlying rocks and through the natural infilt-
ration from lakes and rivers.  This same groundwater is brought
up to the surface by wells for human, animal, and agricultural
consumption, making groundwater and surface water integral
parts of a single dynamic system in which the water contin-
uously flows between the two levels of the system.  The quality
of the water changes continuously as a result of this inter-
face.

Groundwater pollution usually takes place very slowly.  This
is due to the slow movement of the sub-surface water into the
aquifer.  It may take many years to pollute groundwater due to
its slow movement.  However, once groundwater is polluted it
may take many many more years, even centuries, and enormous
cost, to restore the quality of the water even after the
source of the pollution is removed.  It is cheaper and easier
to prevent pollution in subsurface water than to remove it.

There are two basic problems with groundwater contaminations.
The first is handling existing cases and the second is to
prevent new occurrences.  Groundwater pollution arises both
from natural phenomena and as the result of careless and
deliberate acts of man.  Subsurface water pollution can be the
result of excessive and uncontrolled fertilization, pesti-
cides, industrial and animal wastes, irrigation, disposal of
oil field brines and highway deicing salts, accidental spill-
age of hazardous and toxic materials, injection of contamina-
tion into wells for waste disposal, and other causes.

Groundwater quality is an important public concern because of
its effect on the health of man and animals and on the growth
of vegetation.  A lowering of groundwater quality can change
the pattern of living in a region because water usefulness has
deteriorated.  Poor water quality has caused towns to stop
expanding and even languish.  Feedlots have been obliged to be
relocated when the water supply became unfit for animal con-
sumption.

Man has also contributed to groundwater contamination by
dumping urban, industrial, and agricultural wastes, and by
polluting surface streams which recharge aquifers.  He has
created saline conditions in groundwater by means of oil wells
and extensive irrigations.  Although man's contribution to
contamination is large, not all groundwater contamination is
the result of man's activities.  Some contamination results

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     from minerals leaching from rock formations through which
     water percolates enroute to an aquifer.

B.   Types of Contaminants

     Biological contamination of groundwater may occur when human
     or animal wastes enter an aquifer.  Microorganisms present in
     the wastes may be carried by the groundwater into nearby water
     wells and may cause disease when ingested.  Inorganic chemical
     contamination differs from biological contamination in several
     important ways.  Most important are the indestructibility of
     some inorganic chemicals, the persistence of the pollution
     created by their presence, and the difficulty in their re-
     moval. Nitrates in groundwater from agricultural practices,
     for example, are of increasing concern.  The U. S. Public
     Health Service has specified certain "maximum" concentrations
     for such substances in drinking water [93].  In arid regions,
     inorganic chemical contamination is of great concern to agri-
     cultural water users.  Generally, the quality criteria most
     often applied relate to total salt concentration (total dis-
     solved solids), chloride, sodium, boron, and bicarbonate.
     Water low in salts is usually the most desirable for irri-
     gation, but sometimes only water containing several thousand
     milligrams per liter of salts is available.  High evaporation
     rates and lack of adequate flushing may cause salt accumu-
     lation in the root zone with a resulting decrease in crop
     yields.  Reuse and recycling of water for irrigation is a
     frequent source of salt buildup in both surface and ground-
     water  [32].

     Organic chemical contamination is most often caused by such
     substances as detergents, gasoline, oil, and phenolic com-
     pounds.  Phosphate contained in detergents and chemical fer-
     tilizers may constitute a hazard  if present in excessive
     concentrations in groundwater.  Gasoline and other hydro-
     carbons often end up as groundwater contaminants because of
     leaking tanks, pipeline breaks, or spills at the land surface.
     The presence of minute concentrations of hydrocarbons may
     result in abandonment of wells because of objectionable odors
     and tastes.  Frequently, chemical additives complicate the
     contamination pattern.  Phenols present in oil refinery or
     chemical plant wastes are often found in groundwaters.  The
     presence of  this contaminant is generally recognized by its
     taste  and odor, which can typically be detected at concent-
     rations as  low as 0.001 mg/1  (the U. S. Public Health Service
     recommended  limit for phenol in drinking water)  [42].

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C.   Movement of Waste Fluids

     To understand the health and other hazards associated with
     groundwater contamination, some familiarity with the basic
     principles of movement of contaminants in a groundwater body
     is necessary.  Groundwater can simply be described as water
     contained in the saturated pore spaces and fractures of hard
     rocks and sediments beneath the land surface.  It usually does
     not exist in a static condition but is constantly in motion.
   '  The rate of groundwater movement is highly variable both
     vertically and horizontally, and may vary from meters per day
     to centimeters per day or less. For example, in fractured
     crystalline rock the movement might be on the order of tens of
     meters per day, whereas in unconsolidated material it might be
     a few centimeters per day.

     The configuration and slope of the water table are important
     considerations in estimating the directions and rates of
     travel of wastes in the subsurface environment.  Contaminants
     dumped in an area where the water table is practically level
     and where little movement of groundwater is occurring will
     tend to stay in place.  However, low gradients can be asso-
     ciated with high aquifer transmissivities in a given area, and
     high gradients with low transmissivities are great, the pol-
     lutant can move rapidly in spite of a relatively flat water
     table.

     The thickness and composition of the unsaturated zone over-
     lying the saturated zone are also important factors.  Espe-
     cially in cases of biological contamination, a thick unsatu-
     rated zone of fine-grained soil can adsorb and filter much of
     the pollutants before they can be introduced into the ground-
     water body itself.

     Once at the top of the water table, fluid wastes generally
     will enter the groundwater system with only minor mixing with
     native groundwater or will float (nitrates for instance) on
     top of the saturated zone.  The contaminant will then move
     with the groundwater toward its ultimate discharge point,
     which commonly is a spring or a river.  Frequently, however,
     groundwater flow patterns are modified because of pumping from
     nearby wells.  In such cases, the hydraulic gradient or slope
     of the water table is toward such a well, and the contaminants
     converge upon the center of pumping and emerge in the well
     discharge.  In most cases, this is how groundwater pollution
     is discovered.

     Under natural conditions and in the absence of pumping,

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     water-table aquifers in the more humid regions discharge
     groundwater continuously into a nearby surface-water body such
     as a lake or river.   Thus,  the groundwater is entering the
     lake or stream and the aquifer itself cannot be contaminated
     by wastes carried by the stream.  When a well is put into
     operation in such an aquifer near a stream, however, ground-
     water levels are lowered and the hydraulic gradient between
     the well and river may be reversed, causing surface water to
     flow toward the well.  If the stream is polluted, contaminated
     river water may thereby be induced to flow to the well.

     According to the laws governing fluid movement in saturated
     material, the direction of groundwater flow will always be
     toward points where the total hydraulic head is lowest. In
     many parts of the Northwest, saline groundwater in deep aqui-
     fers is under high artesian heads, and it can be induced to
     move upward into freshwater aquifers where heads are lower.
     An example would be the situation in which two zones are
     interconnected through abandoned or improperly sealed wells.

D.   Control and Removal of Contaminants

     Because of the generally slow rate of movement of groundwater,
     a pollutant may exist for years before the problem is dis-
     covered.  Contaminating fluids of different densities do not
     always move with the main body of groundwater.  They can float
     near the top of the saturated sediments or sink toward the
     bottom of the aquifer [95].  Thus, determination of the di-
     rection of flow and areal extent of a contaminated groundwater
     body can be complex, and can be accomplished only by a rather
     detailed and costly investigation.
                                                          i
     Generally, the most common approach to dealing with contami-
     nated groundwater is to eliminate the source of pollution as
     quickly as possible, which is not always feasible. Even if the
     source of pollution can be removed, the groundwater contami-
     nation problem still may not be eliminated because a polluted
     groundwater body normally moves and disperses slowly.

     The degree of reduction in concentration of contaminants with
     time is related to such factors as the hydraulic properties of
     the aquifer and recharge conditions.  Nevertheless, long after
     a source of pollution has been  removed, it is not uncommon for
     the contaminated groundwater body to continue expanding in
     areal extent for many years and to travel  significant  dis-
     tances before its hazardous effects are minimized.  Few

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studies have been conducted to define the degree to which
contaminants will attenuate with time and distance from the
source.  Some recent modeling investigations simulating varia-
tion of groundwater quality with time and distance are ex-
pected to assist in the prediction of contaminant movement.

Other approaches to the solution of groundwater contamination
problems are containment or removal of the pollutant.  Con-
tainment involves limiting the spread of the pollutant within
an affected aquifer.  Pumping from wells, installation of
drains, excavation of affected soils, and artificial recharg-
ing are the most common methods used for containment or re-
moval .

Monitoring Groundwater Quality

Another aspect of groundwater contamination is the problem of
monitoring chemical and biological quality.  Several factors
are responsible for this difficulty, including:

(a)  The complex nature of aquifer systems and groundwater
     movement.

(b)  The variety of potential contamination sources.

(c)  The frequent lack of baseline data.

(d)  The economics of establishing, a monitoring system.

The complexity of hydrdgeplogic conditions was mentioned in
previous paragraphs.  In most cases it is necessary to define
the extent, thickness, direction and rate of movement of the
polluted body of groundwater.  This requires test wells and
often geophysical surveys.  The groundwater quality at various
depths below the surface must be determined.  Chemical tracers
may be introduced into the aquifer to study direction and rate
of flow of the groundwater. Many wastes are of complex chemi-
cal composition, and combinations of different wastes may
produce reactions necessitating extensive laboratory work and
research to establish the source of pollution.

A significant problem in monitoring groundwater quality is the
general lack of baseline data.  Usually, no thought is given
to a monitoring program until such time as a problem is de-
tected, often too late to establish a meaningful program.
Even where water quality baseline data are available, the
information is of limited value because in the past many

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     key constituents  were not  routinely  analyzed  [90].   This
     applies to many of  the trace elements  such as  selenium,  molyb-
     denum,  and cadmium,  and such other toxic metals as  lead  and
     zinc.

     Finally, the problem of economics influences  the establishment
     of a monitoring program.   Federal, state,  and  often county
     legislation have  pointed to the need for  increased  surveil-
     lance  of waste discharge movement.  Yet,  because of limited
     funds  and personnel, a hazard must be quite severe  before a
     polluter, enforcing agency, or water user assumes the economic
     burden of establishing a monitoring system.

     Certainly the majority of small municipal water-supply com-
     panies lack both  financing and personnel  to establish moni-
     toring programs routinely.  Also, most state agencies do not
     have adequate financial resources for sufficient trained
     personnel to enforce effective procedures.

F.   Sources of Information

     In determining the quality of groundwater to be used for
     public drinking water supplies, several sources of  information
     have been used.  Hydrologic, geologic, edaphic, climatic,
     chemical and agricultural data sources were found and uti-
     lized.

     Information on the quantities of groundwater were obtained
     from the U. S. Geological Survey  (Murray and Reeves, Circular
     676).   Here it is revealed that beneath the conterminous
     United States lie some 65 quadrillion gallons or 200 billion
     acre-feet of groundwater within a few thousand feet of  the
     land surface, part of which is renewable upon use.   About 69
     billion gallons a day  (77.3 million acre-feet a year) are
     derived from groundwater reservoirs.  This rate, amounting to
     approximately 20 percent of the total withdrawal use of water
     in th'e nation excluding hydroelectric use, constitutes  only a
     fraction of the development possible, and  the resource  is
     capable of a greatly enlarged role in national water supply
     [56].

     Figure l-II-l shows the magnitude and distribution of ground-
     water utilization in the United States [94].  Although  ground-
     water  is a significant source of water supply throughout  the
     country, predominant usage  is in  the western part, mainly  for
     irrigation.

     The nation's systems of groundwater reservoirs vary  from

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                         Figure  3.-II-1.  '  • .        •:•




Groundwater withdrawn, by regions,  1970 in, million gallons a day
                                10

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reservoirs that are drained and refilled naturally on an
annual cycle, to those in which the annual replenishment is
but a minor fraction of amounts in storage.  Many of the
groundwater reservoirs where replenishment is very low in
comparison to total volume in storage are in the arid West;
significant annual replenishment is more common in the East
and other relatively wet areas of the nation.  Beyond this
general regional classification, conditions of groundwater
availability are as varied as the multifarious hydrological
settings throughout the country [94].  (See Figure 1-II-2)
[85].

About one-third of the nation is underlain by groundwater
reservoirs generally capable of yielding at least 50 gallons a
minute to a well, and there are large areas where hundreds or
even thousands of gallons per minute can be obtained from
wells or springs [94].  (See Figure 1-II-2) Generally, if a
public water supply is drawn from a groundwater reservoir it
will require a well to pump at a rate of at least 50 gallons
per minute.  Figure 1-II-2 indicates those areas in which our
major productive aquifers occur [94, 74].

When a map of agricultural regions is superimposed on this map
large areas of the country were eliminated from consideration.
Crop producing areas are shown in Figure 1-II-3  [73, 80].  A
map of cattle feeding areas is given in the "Feedlots" sec-
tion.  The remaining areas became the focus for various  situa-
tions such as fertilizer application [30], pesticide appli-
cation [81], and feedlot operation  [77].

Alluvial soils in river basins make aquifers there parti-
cularly susceptible to high rates of recharge, and thus  po-
tentially vulnerable to contamination from, for example,
feedlot operations  [44].  These operations were identified
from the U. S. Department of Agriculture Statistical Reporting
Service.  It was ascertained that feedlot  operations have
indeed contaminated some groundwaters in some regions, es-
pecially along the Platte River  [44, 72] and in areas of Iowa
and Illinois  [88].  In Iowa and Illinois the sand content  in
the soils contribute  to this problem due to  their high per-
meability.

In areas where the high water  table  is lowered by heavy
pumping rates for summer irrigation, but raised again in the
winter, there have been problems of high levels of nitrate in
the Fall and Winter.   This is  related to enhanced precipi-
tation and  in part  to  the lower demand for nitrates  in  that
season by plants, the  decay of vegetation, and the
                        11

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UNtTED STATES DEPARTMENT OF THE INTERIOR
           GEOLOGICAL SURVEY
WATER-SUPPLY PAPER ISOO
       PLATE I
   Pattern* detiiM*tc BTCM underlain by o«e
    or nor* muiltn capable of rieldioc to
         l *dU *t lent M ffaa of wttcr
                                       ± «nifcn intertwhkd with
                               or ovcrtain by ODCWMbdMcd or »«jJeoo-
                                    i »juihn
                                Coatonnof «aDwlnmoff.»iaA«»
                                              GENERALIZED MAP  SHOWING  ANNUAL RUNOFF AND  PRODUCTIVE  AQUIFERS
                                                                    IN THE CONTERMINOUS UNITED STATES
                                                                                       SCALE MO 000 01
                                                                                    Figure  1-II-2

-------
Notes:
1.  Ref.:  C.R. Taylor and E.R.  Swanson,  The Economic Impact of Selected Nitrogen Restorations on
    Agriculture and 20 Other Regions in the United States,  University of Illinois at Urbana - Champaign
    March, 1975.
2.  List of areas corresponding  to region number as available from the authors.
3.  Crop production in the shaded areas is minimal.
                                    Figure 1-II-3  Crop Producing Regions

-------
decrease in tillage practices [1].

Figure 1-II-2 includes the surface runoff of water from the
land.  Relating this with the pattern of precipitation (Figure
1-II-5); an estimate of aquifer recharge potential is deve-
loped  (Figure 1-II-4).  It.should be recognized that the soil
retention level of the precipitation is not so high as would
appear from Figure 1-II-5 [94].  Evapotranspiration accounts
for much loss of water from the soil.  In the arid regions
west of the Mississippi River, there is often less than an
inch of recharge whereas Figure 1-II-4 suggests several inches
in most arid regions  [54].  The Agricultural Research Service
of USDA has investigated this rate for many soils and crops in
connection with practices and climatic conditions.  State and
county extension services in many regions have developed data
of this type also.  The evapotranspiration rates are highly
variable depending on a multitude of parameters [70].

Data is presented in various forms and formats.  The farm
producing regions are presented by the U. S. Department of
Agriculture as shown in Figure 1-II-6 [81].  The U. S. Bureau
of Census lists fertilizer consumption with the regions divi-
ded as shown in Figure 1-II-7  [37].

There  are several sources of data on fertilizer consumption.
The U. S. Department of Agriculture publishes Agricultural
Statistics and also Commercial Fertilizers, Consumption in
the United States [78].  The U. S. Bureau of Census publishes
Agricultural Statistics also  [79].  The National Fertilizer
Development Center of the Tennessee Valley Authority published
the 1974 Fertilizer Summary Data  (ed. Normal L. Hargett)  [30],
which  gives an extensive breakdown of fertilizer usage by
crop,  state and composition.  These data can be further de-
fined  by contacting individual state and local extension
service units.  The University of Maryland's Bureau of Busi-
ness and Economic Research has projected consumption of fer-
tilizers throughout the United States for the years 1971
through 1985.  In 1974 there were approximately 175 million
fertilized acres  [37].

Feedlot statistics have been obtained through the U. S. De-
partment of Agriculture, the EPA, and the Bureau of Census
[77].  The University of Maryland's Bureau of Business and
Economic Research has made predictions of growth rates of
feedlot beef production through 1983  [37]. Further feedlot
information is included in the "Feedlots" section of "Nit-
rates".
                        14

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         UNITED STATES DEPARTMENT OF THE  INTERIOR
                      GEOLOGICAL SURVEY
WATER-SUPPLY PAPER 1800
        PLATE 2
Ln
         for Select
  on National Water SUeourcee of
  the United Statee Senata by Usa
  United Statee Department of
  Agriculture. 1959.
                         Prepared fram feohyetal atop by
                         U. 8. Department of Commerce,
                         Weather Bureau data ba**d OB
                         JO year normal*, 19Zl-19SOof
                         2T4 etattona, •oppl.m.nled by
                                                                                                                 Isohyetal line
                                                                                                                 prtdpiuriofi, in irtchua.
                                                                                                                     irrtgultr
                                                                                                          Boundary of water-resource region
                                                                                                                Se« also plate 4
                                            PRECIPITATION MAP  OF  THE  CONTERMINOUS  UNITED  STATES
                                                                         300        0 	.  3QO	6OO	9OO KILOMETERS
                                                                                 Figure  1-II-4

-------
UNITED STATES  DEPARTMENT OF THE INTERIOR
            GEOLOGICAL' SURVEY .
SUPPLY PAPER 1800
 PLATE 3
                                                                                                                                       prepared for Select
                                                                                                                                               Vatar Resourcee of
                                                                                                                                       the Unit** &(•«*• Stn&te by tb*
                                                                                                                                       United Stttoe D«n*rtii>ent at
                                                                                            "Precipitation retained" line
                                                                                               s prtcipitotion mmul runoff,
                                                                                                incnts; mttrvtl
                           PRECIPITATION RETAINED  MAP  OF  THE  CONTERMINOUS UNITED  STATES
                                                           300       0	3OO	6OO	9OO KlLOMCTERS
                                                                   Figure  1-II-5

-------
U.S. DEPARTMENT OF AGRICULTURE
                                                          NEC. ERS 1399-42 (8) ECONOMIC RESEARCH SERVICE
                                    Figure 1-II-6




                              Farm Production Regions
                                            17

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SOURCE:  U.S. Bu.eou of Cenjui, 1964
                            Figure  1-II-7




        Fertilizer-Consuming Regions in the United  States
                                   18

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The distribution of soils [51] and geology throughout the
United States has been compiled and mapped by the Soil Con-
servation Service (USGS sheet number 86, titled "Soils" [91]
and USGS sheet number 74, titled "Geology") [92]. Thes'e map-
pings are not included in this report because of their size
and detail and multicoloring.  The soils map and the accom-
panying soils descriptions is very useful in conjunction with
other maps to focus our attention on areas where problems of
agricultural impact on groundwater are most likely to occur.
The USDA has also an ongoing program for defining soil pro-
perties throughout the United States. State and local agri-
cultural extension services have files on details of soils and
some geology within their jurisdiction.  Land grant colleges
in each state have received Federal funds over the years and
have studied local soils extensively.  However, there is still
a need to better characterize the relationships of soil, crop,
and nitrate-N reactions in many areas.

The groundwater quality data, while still relatively limited,
is available from several sources.  It has come from the Soil
Conservation Service, the U. S. Geological Survey, from state
geological surveys (often the state programs are cooperative
arrangements with the USGS), and EPA reports.  Further soil,
hydrology, and water quality information is available through
the files of the Water Resources Departments and the Water
Resources Research Centers of each state.  The latter source
is the more valuable source of information because of its
research nature.  The major problem involves access to the
data.  Although the data is available, it is not formally
published, but exists in reports in files in the various
centers and departments.  Fortunately the centers do publish a
list of the reports on a biweekly basis.  A note of interest
is that each Water Resources Research Center is given a grant
of $100,000 a year by the Department of Interior  [101].  It
is anticipated that cooperation with these centers will be
invaluable in identifying problems.  Data on water table
depths and aquifer profiles are compiled from well digger
reports.

It should be noted that  the mixing of agricultural pollutants
in an aquifer is minimal because of  the predominance of lami-
nal flow in these bodies  [95].  The nitrates and pesticides
that do enter an aquifer through percolation tend to "float"
in the upper level of the aquifer.  When using well data to
determine the degree of  contamination in an aquifer it  is
important to know the depth  in the aquifer at which the sample
was taken.  It is also important to know whether  the draw down
of the aquifer has been  sufficient to bring waters from the
                        19

-------
     upper layer into the pumped region.

     The condition of the well casing can affect the water drawn.
     If the casing is permeable the well is very susceptible to
     seepage of nitrates and fertilizers into the aquifer.

     Data taken during the Fall and Winter months will tend to show
     higher nitrate concentrations [2].  Data should therefore be
     identified as to the season in which it was taken.

     Climatological data is obtained primarily from the National
     Weather Service of the National Oceanographic and Atmospheric
     Administration (NOAA).  The data on surface runoff, evapo-
     transpiration, and percolation through the ground are the
     realm of the USGS, Soil Conservation Service, the Corps of
     Engineers and to a lesser degree, the US.DA.

G.   Groundwater Assessment

     Generally, groundwater quality in the United States has not
     yet suffered severe degradation from  agriculture.  Locally,
     aquifers have been degraded due to operations of feedlots
     without proper controls 6r in connection with excessive and
     poorly timed fertilizer applications and.other popr agri-
     cultural practices, including, in a few reported instances,
     careless pesticide applications.  The objective is to prevent
     further deterioration .of aquifers from"which public drinking
     supplies are drawn.  The second problem is to determine what
     future deterioration is to" be anticipated with respect to
     various agricultural practices, with projected changes in
     operational parameters incorporated.  This will require the
     use of mathematical modeling and computer simulation.

     It is believed that as farmers .become more scientific, and
     even more economical in their practices, the polluting impact
     of their operations will be reduced significantly.. Two major
     points need to be considered:   (a) more information is re-
     quired on plant demand for nutrients and the proper rotation
     of crops to minimize nitrate percolation through soils [67];
     (b) farmers must make better .use of extension services and
     other good agricultural sources to determine the characte-
     ristics of their, soils, even to. the extent of fertilizing and
     planting their farms at different times and rates  [102].

     Feedlot waste handling and. disposal needs further assessment
     [65.].  New containment, and .application practices are now
                            20

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          available and sometimes in use.   A broad program of assessing
          the effectiveness of these techniques in preventing ground-
          water (and surface water,  too) contamination is essential.
          This will require monitoring of various feedlot sites and the
          adjoining fields for a set of interesting locales (in terms of
          soil type, climate, animal population, etc.).
III. NITRATES

     A.   Nitrogen Cycle
          High nitrate concentrations in drinking water are a potential
          health hazard and should be of concern to the user. They not
          only render the water unsafe for use in infant feeding, but
          generally indicate that the supply is contaminated [50].

          The element nitrogen is a gas composing about 79 percent of
          the earth's atmosphere.  It is relatively inert to chemical
          reaction and ordinarily does not occur abundantly in rocks or
          water, either in elemental form or in compounds.  However,
          nitrogen and nitrogen compounds, which are essential to plant
          life and growth, do occur abundantly in soils and subsoils.
          Their presence there is due largely to bacterial action.
          Certain bacteria remove nitrogen from the air and fix it in
          plants and soils in the form of ammonia and more complex
          compounds, whereas other bacteria change nitrogen compounds
          from one form to another.  Other sources of nitrogen compounds
          in the soil are nitrogen-fixing legumes, decomposing plant and
          animal tissues, animal and human wastes, nitrogen fertilizers,
          and surprisingly, lightning [19].  Because urea, a nitrogen
          compound in the waste of all animals, is readily converted to
          nitrate by bacterial action, barnyard and feedlot wastes are
          locally important contributors of nitrogen compounds to the
          soil.  Septic tanks, cesspools, privies and sewage outlets to
          the soil, together with silo seepage, also are local sources
          of contamination.  Ways in which nitrogen compounds accumulate
          in the soil and are changed from one to another are referred
          to as the nitrogen cycle.

          There are three major forms of nitrogen in mineral soils:  (a)
          organic nitrogen compounds associated with the soil humus,  (b)
          ammonium nitrogen adsorbed by certain clay minerals, and  (c)
          soluble inorganic ammonium and nitrogen compounds  [50].
                                 21

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Most of the nitrogen in soils is associated with the organic
matter.  In this form it is protected from rapid microbial
release, only 2-3 percent a year being mineralized under
normal conditions [50]. About half the organic nitrogen is
known to be in the form of amino compounds.  The form of the
remainder is uncertain.

Some of the clay minerals have the ability to fix ammonium
nitrogen between their crystal units.  The amount fixed varies
depending on the nature and amount of clay present. Up to 8
percent of the total nitrogen in surface soils and 40 percent
of that in subsoils has been found to be in the "clay-fixed"
form [50].  In most cases, however, both these figures would
be considerably lower.  Even so, the nitrogen so fixed is only
slowly available to plants and microorganisms.

In all soils there is considerable intake and release loss of
nitrogen in the course of a year accompanied by many complex
transformations.  Some of these changes may be partially
controlled by man while others are beyond his command.  This
interlocking succession of largely biochemical reactions
constitutes the nitrogen cycle  (See Figure l-III-l) [4].
It has attracted scientific study for years, and its practical
significance is beyond question.

The nitrogen income of arable soils is derived from such
materials as commercial fertilizers, crop residues, green and
farm manures, and ammonium and nitrate salts brought down by
precipitation.  In addition, there is the fixation of at-
mospheric nitrogen accomplished by certain microorganisms.
The depletion is due to crop removal, drainage, erosion, and
to loss in a gaseous form.

Much of the nitrogen added to the soil undergoes many complex
transformations before it is removed.  Proteins are converted
into various decomposition products, and finally some of the
nitrogen appears in the nitrate form.  There are nitrifi-
cation, mineralization, and denitrification processes which
take place.

Mineralization  (or ammonification) is the breakdown of organic
nitrogen to ammonium.  Nitrification is the oxidation of this
ammonium, or ammonium from fertilizers, to nitrate. Factors
affecting this process are soil characteristics, water con-
tent, aeration, and temperature.  The rate of nitrification
tends to decrease sharply when the oxygen content of soil
falls below 2 percent or when soil air space is nearly saturated
                               22

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                                              ANIMALS
                   N-FIXATION
                      >r
                   FERTILIZER
                    and RAIN
                                                          LOSSES
GASEOUS LOSS
 RESIDUES,
 MANURES
and WASTES
                                       SOIL ORGANIC
                                          MATTER
                                           l\
                         -NH/
                        Figure l-III-l

            Major Phases of the  Nitrogen Cycle
                                23

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with water.  The maximum rate of nitrification occurs in soil
temperatures of about 30° C. and is very slow at 7° C.
Nitrate can be used by plants, denitrified, leached to ground-
water, or remain in the soil and be available for subsequent
crops.

Denitrification is the microbial reduction of nitrate to
harmless nitrogen gas [4].  It is an important factor in
determining the amount of nitrate available for leaching to
groundwater.  Denitrification generally takes place in soils
when anaerobic conditions prevail and an energy source such as
decaying organic matter is present.  Organic nitrogen and
ammonium forms must be oxidized to nitrate before denitri-
fication takes place.

Under favorable conditions, a substantial amount of denitri-
fication occurs in or near submerged tile drains.  This de-
creases the amount of nitrates present in the tile drain
effluent.  Denitrification also removes nitrate from the root
zones of crops, such as rice, that are submerged in water for
extended periods of time.

Temperature affects the mineralization or ammonification of
nitrogen, which influences the nutrient content of runoff and
leached waters.  During cold periods, plant activity is re-
tarded, thereby reducing the rate of nutrient utilization and
water consumption.  Variability in temperature is also im-
portant.  If frozen land is thawed at the surface by rainfall,
leaving a frozen sublayer that prevents percolation of water,
surface runoff and erosion occur.  Freezing of plant material
tends to rupture plant cells, and nutrients are then subject
to leaching during spring thaw.

The nutrient content, permeability, and structure of agri-
cultural soils are important factors that may have a bearing
on the nitrate in ground and surface water.  The nutrient
accumulation in the soil and substrata is a function of basic
soil properites, geologic deposits, decomposition of organic
matter and peat, presence of nitrogen-fixing plants, soil
organisms, animal and human wastes, and inorganic sources such
as fertilizer and precipitation.

The energy associated with the impact of falling raindrops
affects the amount of sediment in runoff and the rate of water
infiltration.  Adequate ground cover will absorb the raindrop
impact and protect the surface cover.  Forests and grasslands
generally have higher rates of water infiltration than plan-
tings of agricultural row crops when soil and slope conditions
are otherwise equal.
                     24

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Permeability and water retention characteristics of soil
affect the amount of water passing through the root zone. If
nitrate is present, it will move with the water and may even-
tually enter the groundwater.  The concentration of nitrate in
the groundwater depends on the amount of nitrate leached, the
volume of water passing through the soil profile, and the
transit time of the leachate from root zone to water table.
Transit time is related to the hydraulic conductivity of the
soil profile, depth of the water table, and degree of soil
saturation.  In some areas it may take 20-30 years for the
leachate to pass from the root zone to the water table.  A
sandy soil will not retain as much water in the root zone as a
loam soil, and so has a higher leaching hazard.  Therefore,
less nitrogen is utilized by plants and more nitrogen is
leached below the root zone in sandy than in less permeable
soils.

Geologic materials underlying soils may restrict the downward
movement of water.  Under such circumstances, nitrogen will
not contaminate deep aquifers, but may accumulate in perched
water tables.

Ordinarily, most of the nitrate in groundwater has been leach-
ed from the soil by infiltrating precipitation.  Thus, where
nitrate is especially abundant in the soil, the groundwater
generally is high in nitrate.  Very high concentrations in
well water often are due to contaminants reaching the water
table at or near the well site.  For example, a poorly fitting
well cover permits contaminants to enter the well directly,
and open space or highly porous material surrounding the well
casing permits contaminants  to infiltrate rapidly to depths
where they can enter the well through holes in the casing  or
through the screen.  Shallow dug wells, particularly those
walled with wood, stone, brick, or jointed tile, are the most
likely to yield high-nitrate water owing to introduction of
contaminants at or near the well site. Generally, high nitrate
concentrations in water from deeper drilled wells are due  to
leaching of nearby tracts of nitrate-enriched  soil and sub-
soil.

Drinking water standards have been set by the  U. S. Public
Health Service  (1962) at a safety limit of 45  ppm nitration,
or 10 ppm nitrate  as nitrogen, as a safeguard  for people using
municipal water  supplies.  Although no limit has been  set
specifically for rural domestic supplies, the  potential  dan-
gers of nitration  concentrations greater  than  45 ppm should be
recognized.
                      25

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B.   Health Effects of Nitrate

     The best known problem due to nitrate consumption is methe-
     moglobinemia, a cyanosis which is brought about by reduction
     of nitrate (NC>3) to nitrite (N02) by bacteria in the digestive
     tract, followed by absorption of the nitrite into the blood-
     stream where the nitrite oxidizes the ferrous ion (Fe  ) *n
     hemoglobin to ferric ion (Pe*44"), thereby preventing the
     transport of oxygen by the hemoglobin.  This results in a
     gradual suffocation (cyanosis).  Infants are most susceptible
     since the acidity of their stomachs is considerably less than
     that of adults, resulting in a more favorable environment for
     the nitrate-reducing bacteria. The digestive system of animals
     such as cattle (ruminants) also is conducive to this bacterial
     action.  Therefore, when a nitrate problem occurs, it is first
     reflected in health problems of cattle or human infants [50].

     Methemoglobinemia is not well understood.  The nitrate or
     nitrite concentration at which methemoglobinemia becomes a
     problem may vary widely, and is most likely influenced by some
     as yet unidentified factor or factors.  Because of the methe-
     moglobinemia problem, the U. S. Public Health Service has set
     a recommended maximum limit of 45 ppm nitration for potable
     water.  However, water containing over 1000 ppm nitrate has
     been found with no apparent ill effects to the local popu-
     lation.  In other areas, methemoglobinemia has resulted from
     using water with as little as 50 ppm nitration [9].   Clearly,
     more work is needed in the whole area of methemglobinemia.

     One point deserves further clarification.  The high suscepti-
     bility of animals and human infants to methemoglobinemia
     derives from the bacteria in their digestive systems which can
     convert nitrate to nitrite.  If the water which is being
     consumed already contains nitrite, however, even healthy
     adults will be susceptible.  The presence of nitrite in drink-
     ing water results from at least two known causes.  First, if
     the contamination is from surface pollution (e.g., barnyards
     or septic tanks) nitrite can be present due to incomplete
     oxidation of the nitrogenous waste materials.  Second, nitrate
     in the groundwater can be reduced to nitrite by a chemical
     reaction with iron pipe or zinc coated (galvanized) pipe.
     This reaction consists of corrosion of the metal, with the
     nitrate acting as a hydrogen depolarizer.

     Water contaminated with nitrate cannot be purified by boiling.
     The nitrate concentration will instead be increased due to the
     loss of water by evaporation.
                          26

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     There is increasing evidence that nitrate and especially
     nitrite may be linked to cancer.   It was shown by Lijinsky and
     Epstein [43] that nitrite can react, under the conditions of
     temperature and acidity in the human stomach, with secondary
     amines (from cooked foods) to form nitrosamines, some types of
     which are highly carcinogenic.  Other studies also indicate a
     relationship between nitrate and cancer.  If such a relation-
     ship is proven, the Public Health Service limit of 45 ppm for
     nitration in drinking water will have to be reevaluated.  In
     addition, it may be even more important to set limits on
     nitrite in drinking water.

     Clearly not all the effects of nitrate are yet known; but it
     is believed that livestock may develop thyroid problems,
     rickets, enteritis, arthritis, and generally poor health from
     ingesting nitrates.

C.   Fertilizers

     Fertilizer Nitrogen.  Fertilizers are one of the major agri-
     cultural sources of potential pollution of the groundwater.
     The three major elements in fertilizers are nitrogen (N),
     phosphorous (P) and potassium (K).  Nitrogen is the main
     pollutant in the form of nitrates.  During 1973, 43 million
     tons of fertilizer material were applied throughout the United
     States, of which 8.3 million, 5.1 million, and 4.6 million
     tons were nitrogen, phosphorous, and potassium, respectively
     [30].
       • .                                                  i
     To meet the increasing demand for food by an expanding popu-
     lation, oxidized soluble forms of nitrogen have been intro-
     duced through new technology  to supplement the slow process of
     nitrification and symbiotic N fixation.  This effort has
     resulted in greater use of commercial nitrogen, often in
     addition to heavy application of manure.  All nitrates are
     water soluble and have the potential to move into the ground-
     water and thereby create a potential health hazard.  The
     atmosphere  is usually considered to contribute from 2 to 6
     pounds of nitrogen  to an acre of land per year  (Allison  [3],
     Eliassen, et al  [18], Hutchinson, et al  [34]).

     Several studies have been conducted on  the occurrence of
     nitrite and nitrate in water  supply systems  (Smith  [66],
     Doneen  [15]; McHarg; Erwin, et al  [20]; Murphy et al  [49]).
     Very little is known of the extent  of fluctuation in nitrate
     concentration  in water wells.  Contaminating sources have
     seldom been pinpointed.   Environmental  variables, well  depth,
     well location, precipitation  and agricultural practices  con-
     tribute to  the above fluctuations.
                          27

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Nitrate derived from biological fixation of atmospheric
nitrogen and nitrification are discussed in the following
reports:  Starky [71]; Hirsch [33]; Marshall, et al [46];
Brezonik [7]; McCoy [47]; Thompson [75], and other reports.
Nitrate from naturally occurring deposits were discussed by
Mansfield,  et al [45], and Ingols, et al [35].  The intrusion
of inorganic nitrogen originating from farmland as a potential
source of nitrate-nitrogen in both surface and groundwater
supply is discussed in the following papers:  Corey, et al
[11], Stewart, et al  [72], Commoner  [10], Krause, et al  [40],
Harmeson, et al [31], Welch and Kohl, et al  [39].

The concentration of nitrate in groundwater is generally
highest following wet periods and lowest during dry periods.
Seasonal variations may be further enhanced by other factors
such as geologic structures i.e.:  characteristics and depth
of soil, subsoil and bedrock formation, degree of and inter-
connecting crevices in rock formation, presence of a recharge-
able aquifer and amount of recharge water, as well as amounts
of nitrogen applied.

Olson reported that the maximum downward migration rate of N03
in silt loam soil is in the range of 1 to 1-1/2 feet per year.
The rates for sandy soil will be much higher while those for
clay soils will be lower.

Shallow wells (less than 50 feet in depth) are more apt to
show large and frequent increases or decreases of nitrate
concentration.  Deeper wells tend to show less intensity of
nitrate fluctuations.

Efforts to obtain higher yields per unit of land through
fertilization, whether the fertilizer is organic or inorganic,
nearly always create greater potential for nitrate to be
carried into waterways.  When the efficiency of nitrogen use
becomes low, greater losses of nitrogen occur, particularly in
well drained soils, and the nitrogen may then escape to leach-
ing waters.  Low cost fertilizers tend to encourage ineffi-
cient and excessive usage of nitrogen fertilizer on the farm.

Because intensification of agriculture favors greater decom-
position of native soil nitrogen, the nitrate content of
underground waters may rise.  However, in oxygen-deficient
soils with high water tables, the nitrate may be converted to
nitrogen gas.

In humid regions, the nitrate concentration  in water perco-
lating through cultivated soils is a function of the fertility
                     28

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level of the soils.  The amounts of water percolating through
the soil at any given time, the degree of nitrate removal by
crops, and the activity of denitrifying microorganisms deter-
mine the nitrate concentration in soil leachates.

Industrial nitrogen fertilizers may cause some temporary
changes in the biological processes essential for soil fer-
tility, but the changes are neither permanent nor irrever-
sible.  The benefits of fertilizer use, associated with the
increased availability of an element essential for plant
growth, far outweigh the temporary inhibition of certain soil
microorganisms.

Reducing nutrient losses to groundwater from agricultural
nonpoint sources can be accomplished with two general app-
roaches:  (a) determining and applying appropriate amounts of
plant nutrients at the proper time and in the proper place,
and (b) adopting improved cultural practices, including con-
servation tillage and crop rotations, that minimize nutrient
losses.  Control measures should be selected in light of their
economic and technical feasibility, as well as their effect in
reducing nutrient losses.

Phosphorous in Fertilizers.  When fertilizer phosphate is
added to the soil it is rapidly incorporated into relatively
insoluble compounds.  Because of the insolubility of these
compounds, leaching losses are minimal and so groundwater
contamination from fertilizer phosphorous is not a problem.
Phosphate compounds are generally non-toxic, but tend to cause
eutrophication of surface waters.

Potassium in Fertilizers.  The third macronutrient commonly
added to soils is potassium.  Little is known about its  function
in plants.  Drainage waters from soils to which  potassium has
been added have been shown to contain  considerable quantities
of potassium.  In other instances, more than 90  percent  of the
added potassium has been recovered by  crop removal.

Leaching of potassium depends on the mineral composition, the
amount  of soluble organic matter, and  the base exchange  capa-
city of the soil.

Potassium has not been found to be harmful to humans or  live-
stock.  On the contrary, potassium is  known to be essential to
muscle  tissues in animals.  Some people have been found  to
have a  potassium deficiency.  Though potassium may enter a
groundwater supply,  its effects have not been found to be
harmful.
                      29

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D.   Feedlots
     Animal Wastes/General.  Livestock and poultry production in
     the U. S. is becoming concentrated in large scale, confinement
     type operations.  These include multi-hundred - cow dairy
     operations, multi-thousand - head beef and hog feedlots and
     enterprises with many thousands of birds.  Such large con-
     centration of animals and birds have greatly magnified the
     problem of handling the animal wastes.  Production of wastes
     by livestock is summarized in Table l-III-l [98]. , Population
     equivalent by various kinds of livestock is given in Table 1-
     III-2 [98].  For example, a feedlot of 10,000 head of cattle
     has about the same waste disposal problem as a city of 164,000
     people.   Such a city will use approximately 8.2 mgd to carry
     off the sewage  [98].  Such quantities of water are never used
     and seldom available at feedlots.  The composition of some
     animal wastes are given in Table 1-III-3 [57].

     The primary problem in handling animal wastes involves coping
     with the high BOD.  Untreated municipal sewage has a BOD of
     about 100 to 400 ppm.  Wastes carried in runoff from barnyards
     and feedlots may vary in BOD from 100 to 10,000.  Many in-
     stallations use lagoons for oxidation but success has not been
     complete.  Such wastes, when deposited on the soil, can lead
     to higher nitrate concentration as well as higher salt loads
     in the adjacent waters, surface and underground.

     Heterotrophic Nitrification.  The nitrate in soil and ground-
     water may originate from microbial transformation of manure
     returned into the soil.  Traditionally, nitrification was
     considered the work of autotrophus in which ammonium is oxi-
     dized to nitrite and subsequently, to nitrate.  Heterotrophic
     nitrifiers have been reported as potential nitrate by Hirsch,
     et al [33], and Marshall, et al  [45].  Thus, the compounds
     important for nitrification are no longer limited to inorganic
     nitrogen but include a series of amino acids (peptides) which
     may be converted to nitrates.  Thompson  (1969) concluded that
     it is reasonable to assume that nitrate pollution of ground-
     water may be attributed to heterotrophic nitrifiers where
     large amounts of wastes are returned to the soil.

     Denitrifying Organisms.  Present day farming practices often
     lead to situations in which nitrates accumulate faster, by
     nitrification due to heavy application of commercial ferti-
     lizers,  than they are removed by either crops or denitrifi-
     cation.   Crabtree (1972) reported that the total number of

                              30

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                                                     TABLE l-III-l




                            Production  of wastes  by  livestock in the United States. [98]
u>
Livestock

Cattle
Horses [1]
Hogs
Sheep
Chickens
Turkeys
Ducks
rn _ +. _ 1
lotaj.
U.S. population
1965
Millions
107
3
53
26
375
104
11


Solid wastes [1]
G. /cap. /day
23,600
16,100
2,700
1,130
182
448
336


Total production
of solid waste
Million tons/yr.
1,004.0
17.5
57.3
11.8
27.4
19.0
1.6
11 IB f.
, X JO . O
Liquid
wastes
G./cap. /day
9,000
3,600
1,600
680
	
	
	


Total production
of liquid wastes
Million tons/yr.
390.0
4.4
33.9
7.1
	
	
	
A i R A
H JJ . t
        [1]  Geldreich and others.




        [2]  Horses and mules on  farms as work stock.

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                        TABLE 1-III-2




        Population equivalent of the fecal production




by animals, in terms of biochemical oxygen demand (BOD).  [98]
Biotype
Man
Horse
Cow
Sheep
Hog
Hen
Fecal
(G. /cap. /day)
150
16,100
23,600
1,130
2,700
182
Relative BOD/
unit of waste
(lb.)
1.0
0.105
0.105
0.325
0.105
0.115
Population
equivalent
1.0
11.3
16.4
2.45
1.90
.14
                           32

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                    TABLE 1-III-3




Average Daily Manure Production and Composition [57]
ITEM
Wet Manure
Total Solids
Volatile Solids
Nitrogen
P2^5
K20

HOGS
7.000
1.120
0.950
0.050
0.030
0.048
(After Proctor, 1964)
CHICKENS
(lb/d)
0.2500
0.0720
0.0550
0.0040
0.0031
0.0014

CATTLE
(lb/d)
64.00
10.20
8.20
0.38
0.11
0.31

                       33

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denitrifiers increased as the rate of manure application in-
creased.  Denitrifying bacteria were found regardless of
aerated or water logged soils, with or without tho presence of
detectable nitrites or nitrates.  Denitrification and nitrate
reduction by heterotrophics may occur only when a sufficient
amount of nitrite or nitrate is present in a given microbial
environment lacking in other more suitable hydrogen acceptor.

A question inevitably raised is why the accumulation of such
high nitrate content in the groundwater supply exists in the
presence of large number of nitrifiers.  A reasonable ex-
planation is that the denitrifying bacteria formed may not be
active in the denitrification process because the soils are
sufficiently aerobic or lacking in hydrogen donor compounds;
aerobic conditions inhibit the denitrification process re-
gardless of the presence of nitrates.

Feedlot Operations.  Presently, the large, mechanized com-
mercial feedlot accounts for many of the livestock fed for
slaughter. . In the past, animals were fed in small units, and
wastes were considered an asset.  Today, the concentration of
many animals in one unit creates enormous waste-management
problems.  A cattle feedlot of 50,000 capacity covers ap-
proximately 200 acres and produces approximately 450,000 tons
of wet manure and urine annually.  This manure contains about
15,000 tons of dry mineral matter, 60,000 tons of dry organic
matter, and 2,800 tons of nitrogen. Pollution of groundwater
can occur directly beneath the pens, beneath basins used to
impound runoff, and beneath cropland treated with wastes or
runoff from the feedlots.

Increased nitrate concentrations found in Missouri water
supplies have been attributed to feedlots and not to ferti-
lizer use on farms.  In a Colorado study  [72] profile, samples
were obtained from the surface to bedrock or to the water
table.  Nitrate content of the profiles was influenced by land
use.  Nitrate content in 20 feet of profile under cattle
feedlots was as high as 5,000 Ib per acre, the average for 47
feedlots being 1,436 Ib.  For other kinds of land use the
average values were:  virgin grassland, 90 Ib.; unfertilized
wheat-fallow land, 261 Ib.; and irrigated land not in alfalfa,
506 Ib.  Nitrate gradients in the profile showed accumulations
at the soil surface, with concentrations decreasing with
depth.  Nitrate content in the water at the water table sur-
face, and at the 20 ft. depth in the soil showed little dif-
ference for each land-use [72],  The question is what happened
to the nitrate?  There was evidence that water was moving
                         34

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through the profile and that some nitrate was moving with it.
The decrease in nitrate with depth was attributed to denit-
rification, the process whereby microorganisms reduce nitrate
to nitrogen gas.  The greatest decrease in nitrate concent-
ration occurred under feedlots where an abundant supply of
carbonaceous material was present in the soil water to serve
as an energy source for the microorganisms.  Denitrification,
therefore, appears to be significant in determining the fate
of nitrate moving through soil profiles, particularly those
under barnyards and feedlots.

Even if nitrate concentrations remain low, other pollutants
can degrade the quality of groundwater.  The Colorado study
revealed that several wells were abandoned near feedlots, even
for livestock use, because of poor water quality.  The largest
differences between water samples collected under feedlots and
adjacent irrigated fields were in the concentration of ammo-
nium and organic carbon, a measure of soluble organic matter
[72].

The literature has shown that feedlots can have a notable
impact on the quality of groundwater.  Feedlot design factors
which may affect groundwater should be investigated and manage-
ment techniques re-evaluated.

Cattle-Feeding Areas.  Not long ago cattle feeding was almost
synonymous with Corn Belt feeding.  There the surplus grains
were available for feeder cattle brought from the range areas.
Since then cattle feeding has begun to develop in other re-
gions also.  Areas in California, Arizona, the Plains States,
and Colorado represent some of the newer centers of concent-
ration of cattle feeding. (Figure 1-III-2) [77].

Cattle feeding is a major activity in those areas where the
combination of feed supplies, feeder cattle, markets, and
other resources are favorably balanced.  In each region,
however, there are specific locations in which feeding oper-
ations are concentrated.  Some of these locations cover broad
geographic areas, as in the northern portion of the Corn Belt
while in other regions, the industry is confined to small
areas.  The fed cattle marketed in 23 major states is given in
Figure 1-III-3  [65],

Nearly all parts of the country now have some cattle feeding,
Such regions as the Southeastern and mountain States account
for hardly more than 2 or 3 percent of the number of cattle
fed nationally, but each region has several areas of concen-
tration.  These areas are small, but their level of output

                         35

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  Colllt Ittding arioi nprtsont location
    but not Kolumt of tollli lit.
U.S. DEPAtTMENT OF AGIICUITUIE
                                              NEC. EIS 7*91-70 (5)   ECONOMIC IESEAICH SERVICE
                              Figure  1-III-2

                           Cattle  Feeding  Area
                                       36

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CO
                                                    Figure 1-III-3




                                        Feed Cattle Marketed in 23 Major States

-------
     is sufficient to make feeding of significance to the agri-
     cultural economy of the local areas.

E.   Septic Tank Systems (On Site Domestic Waste Disposal)

     The three most commonly used systems for on site domestic
     waste disposal are the septic tank and its associated sub-
     surface distribution system, the cesspool and the privy.  The
     septic tank system is the most acceptable and sophisticated of
     the on site domestic disposal methods, and is installed at new
     housing sites when local ordinances permit and when public
     sewer service is unavailable.  The cesspool, which is no
     longer generally approved, is usually an underground sump
     filled with stones and is intended to settle out larger solids
     discharged from domestic plumbing.  These systems work well
     only in very coarse or highly fissured materials, but in
     essence discharge raw sewage which moves easily to ground-
     water.  The privy is usually designed as an open pit privy or
     closed vault privy.  These are usually located where pres-
     surized water is not available.  Because the open pit gene-
     rally receives only human wastes and paper the potential for
     groundwater pollution is small.  Closed vault privies retain
     all wastes and must be pumped out periodically, and so are not
     usually a groundwater problem. Problems often associated with
     privies are odor, disease-carrying insects, and maintenance.

     About twenty million individual housing units, representing
     about 29% of the United States, discharge their domestic
     wastes through individual on-site disposal units.  These are
     primarily (85%) septic tanks and cesspools.  Of this number
     cesspools account for about two hundred thousand units [89].
     The principal factors and variables which determine the mag-
     nitude of the problems from septic systems as would be found
     on farms are the geology, the depth to the water table, the
     precipitation, and the location and design of the system with
     respect to other facilities  [42].

     Individual problems of well contamination can occur anywhere
     in the country, but when the problem is the result of con-
     tamination from the septic system it can usually be corrected
     by the redesign or relocation of the well or septic system.
     Very often the well has been poorly cased or located, in which
     event nitrate and coliform contamination can be expected  [89].

     Areas in which there are less than 10 septic systems per
     square mile do not present a threat to public drinking water
     supplies which draw from groundwater, except where the septic
                              38

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          system is  located  too  close  to  the  well  and  causes  direct
          contamination [89].

          It is hard to differentiate  the effects  of nitrate  pollution
          of groundwater by  a  septic system from those of  a barnyard
          or feedlot,  if these sources are within  close proximity of
          each other.

          Data on the density  of septic systems has been obtained
          through the 1970 Census of Housing  [83]. The control of
          septic systems is  generally  through local, county,  or state
          agencies.   The records of well  contaminations and septic tank
          failures are kept  in the files  of these  agencies.  The in-
          dividual Water Resources Research Centers also have collected
          data within their  jurisdictions. Most state Environmental
          Health Departments will test water  samples for nitrates free
          of charge.

          Within the EPA the Office of Air and Waste Management has a
          Solid Waste Management Program that includes the assessment of
          problems created by  septic  tank systems.  They are presently
          engaged in determining the dimensions of this problem [89].
          EPA's R. S.  Kerr Environmental  Research  Laboratory at Ada,
          Oklahoma,  has recently initiated a  long  term septic system
          study.
IV.  AGRICULTURAL PESTICIDES

     A.   Introduction and Overview

          In 1964, 693 million pounds of agricultural pesticides -
          insecticides, fungicides and herbicides - were applied to some
          83 million acres of land [98].  When these chemicals are
          applied directly to the environment, it is obviously impossi-
          ble to avoid exposing most, if not all, of the organisms in
          our environment to the insecticides.  In addition, these
          chemicals may not only be hazardous to non-target living
          organisms but may move to other parts of the environment by
          various vectors [24].

          The potential hazard of an agricultural pesticide as a ground7
          water contaminant depends on its solubility, adsorption charac-
          teristics, and biodegradability [87].  A pesticide may be
          extremely toxic, but if its chemical composition is unstable, .
          is rapidly biodegradable or has a low solubility, it may not
          pose a hazard because it may never reach the groundwater.
                              39

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In general, pesticides used in agriculture can be grouped into
five major classes.  Each of these classes has certain phy-
sical and chemical characteristics which are of primary im-
portance in evaluating the potential hazard of such a class as
a groundwater pollutant.  These five classes of pesticides
are:  organic botanicals, organic phosphates, carbamates,
chlorinated hydrocarbons (CH) and organometallic compounds.  A
brief discussion on the potential of each one of these classes
for contaminated groundwater supply is given below.

Chlorinated hydrocarbons are among the most stable of all
pesticides in use today  [28].  Some of the most noted pesti-
cides of this group are DDT, aldrin, dieldrin, endrin, lin-
dane, chlordane, heptachlor and toxaphene.

These pesticides produce long-lasting toxic residues that are
stable in a wide variety of environmental conditions. In some
cases the residues or metabolites may be more toxic than the
original pesticides.  Chlorinated hydrocarbons are known to
have extreme longevity  [67].

Nash and Wilson (1971) reported that 39 percent of the origi-
nal DDT applied to a test plot was recoverable after 17 years.
Dieldrin was reported to be even more stable than DDT. Ter-
riere (1956) investigated the persistence of various chlo-
rinated hydrocarbons and concluded that dieldrin is the most
persistent.  The retention and releases of chlorinated hydro-
carbon residues from soils is dependent on many factors.
Temperature, soil type, and solubility of the pesticide are
the most important factors.  Studies in Wisconsin by Lich-
tenstein (1962) suggest that persistence is also influenced by
the chemical specificity of the insecticide, soil, moisture,
cover crop, soil cultivation, mode of application and soil
micro-organisms [97],

Lichtenstein (1956, a) reported no residue release from chlo-
rinated hydrocarbons where soils are frozen; under higher
temperatures there is a positive correlation between tempera-
ture and the amount of residue released from CH (chlorinated
hydrocarbons).  Swanson  (1954) concluded that adsorption and
not cation or base exchange was the principal mechanism in
retaining lindane residues in soils.  High organic content
soils were shown to retain more CH residue than sandy or mine-
ral soils.  Similar results were obtained by Lichtenstein
(1959, b).  Wheatley  (1960) determined that the half life of
dieldrin in a mineral soil is approximately four years while
the half life in an organic soil is approximately five to
seven years.  Thus, it  can be concluded that the organic

                         40

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content of the soil is a dominant factor in the retention of
CH pesticides residues.

CH pesticide residue can be removed from soil by plants as was
demonstrated by Wheeler (1967).  A few microorganisms are
capable of degrading dieldrin but the factors involved in
microbiological degradation are complex and not well under-
stood (Matsumura 1960).

Due to adsorption processes in soil, the chlorinated hydro-
carbons and their metabolites do not normally percolate into
the subsoil [68].  However, in soils, such as montmorillonite,
which are high in clays of an expanding nature, pesticides can
be transported readily through the cracks which form in these
soils during dry weather.  Chlorinated hydrocarbons have been
found as deep as 70 feet under these conditions [102].

Even though several of the chlorinated hydrocarbon pesticides
have had their registrations cancelled in the U. Si, their
residues may still be present because of their chemical sta-
bility and therefore they may be a potential hazard to ground-
water.  The registration of DDT, aldrin, dieldrin, and endrin
have been cancelled.  Chlordane and heptachlor are presently
being considered for cancellation.

Contamination of groundwater by CH pesticide residue is de-
pendent on their solubility in water as well as adsorption in
the soil matrix.  CH pesticides are considered to be only
slightly soluble in water.  Tests by the Georgia Agricultural
Experiment Station  [98] have shown that:   (a) lindane was one
of the most readily leached; 54 to 88 percent of this chemical
was removed from six soils, (b) no trace of endrin was found
in the leachate .from three soils but 51 to 95 percent of that
added to the other three soils was leached,  (c) dieldrin
showed wide variability in behavior among  six soils.  Only 1
percent was leached from Magnolia sandy loam, whereas 65
percent was removed from Lakeland sand.  Results from the
other four soils were scattered in between these extremes,  (d)
Aldrin was very resistant to leaching.  Only a trace was
removed from five of the soils and 16 percent from the Lake-
land sand, (e) Heptachlor also was very resistant to leaching.
It is interesting to note that these results were obtained
from six sandy soils found within a 50 mile radius of Tifton,
Georgia.  One can only conclude that a greater scatter in the
results will occur  if a wider  range of soils obtained from
different parts .of  the United  States is used.

                         41

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Eye [21] concluded that for one foot of penetration of die-
Idrin residue level of 20 ppb, water must infiltrate a dis-
tance of 360 to 480 feet into the soil.  However, the number
of cases where groundwaters were reported GH contaminated in
the literature is minimal.

It is difficult to estimate the degree of contamination of
groundwater resources because well-water analyses of CH are
not common.  In addition, data on CH residue in groundwater is
usually not reported in the literature unless it is a part of
some particular study.      • •           >

In view of the evidence reported in the literature surveyed it
is likely that chlorinated hydrocarbon-pesticide residue can
be a slight hazard to deep groundwater aquifers.  However, in
areas where shallow water table aquifers are present, a real
potential hazard exists.
                                            i
Carbaryl type pesticides containing nitrogen, .such as Sevin,
break down in the soil in a comparatively short,time and the
resultant metabolic products are non-toxic.  No health hazards
are known to exist from carbaryl pesticides at  the present
time  [17].     •                   ,                  ,

Triazine type heterocyclic pesticides  such as diazinone and
triazinone and their metabolites persist much longer in the
soil  [99].  Very little is known, about the metabolites of
diazinones or triazinones with regard  to toxicity or solu-
bility.  Chemical literature  is still  lacking on groundwater
pollution by these pesticides.  They have not yet been found
to be groundwater pollutants.

Organophosphorous and organosulfur pesticides are broken down
easily  and rapidly in soil and subsoil.  These  compounds are
commonly called nonpersistent pesticides because they are
degraded to less toxic compounds in a  relatively short time
(3-6 months, according to  some studies)  [102].  The degradation
of these compounds is achieved by sunlight, soil bacteria, and
water.  Because of the instability of  the original chemical
structure  and of the  less  toxic, biodegradable  secondary
compounds, it is unlikely  that such compounds may contaminate
deep  groundwater sources.  The time required for these com-
pounds  to  reach deep  groundwaters is sufficient for soil
bacteria to attach and degrade them.

Organometallic pesticides  are those which contain metallic
elements in the  structure.   There are  spotty references  to
those toxic metals.   More emphasis  is  put on arsenic-

                          42

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containing pesticides [41].  Arsenic reacts with the cations
of iron, aluminum and calcium.  These are water insoluble
metallic arsenates which pose no health hazard to groundwater.
The presence of phosphorous in the soil affects the phyto-
toxicity of arsenic.  Phosphorous and arsenic are in the same
periodic group and hence have similar chemistry. Arsenic is
removed from the soil by bacterial metabolism which transforms
it into arsenic hydride and its methyl derivatives.  These
metabolites are gaseous and easily removed by volatilization.
Many of the metallic elements in this group of pesticides have
been found to persist in the soil and interfere with plant
growth, but apparently pose little hazard to groundwater.

Organic botanicals are pesticides derived from plant matter
[28].  Such pesticides are manufactured either by extracting
naturally occurring insecticidal compounds from plants or by
grinding plant matter - roots, stems, leaves - of plants which
contain certain insecticidal compounds.  Because of their
origin organic botanicals are quite low in toxicity, both to
plants and warm-blooded animals.  Their primary use is in home
gardens and control of household insects.  Although these
compounds are widely used in households, they are of limited
use in agriculture because of their high cost, very specific
action and a tendency to deteriorate in storage.  In general
organic botanicals have low solubility in water and are ra-
pidly biodegradable, a characteristic which will tend to limit
their potential as a source of contamination of groundwater.
Some of the common members of this group are nicotine sulfate,
rotenone and pyrethrins.

Only a limited number of instances of groundwater contami-
nation by pesticides and herbicides have been reported in the
literature.  It is unlikely that groundwater contamination
from these sources is a serious problem nationwide; as was
pointed out earlier, only chlorinated hydrocarbons residues
are persistent and therefore of concern  [102]. A study con-
ducted by Eye  [21] concluded that for one foot of penetration
of dieldrin residue at a residual level of 20 parts per bil-
lion, water must infiltrate from 360 to 480 feet into the
soil.  Crosby  [13] suggested that if an effective rainfall of
about ten inches infiltrated a given area it would remove only
0.003 of a gram of dieldrin residue per square foot and transport
it to a depth of approximately one-half inch.  The soil for
this case was sandy silt with about 20 percent clay.  Because
of the low solubility, partial degradation, uptake by plants,.
biological attack, volatilization and co-distillation, con-
tamination of groundwater sources by CH residue on a national
                         43

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     scale is not believed to be a problem.   However, in certain
     areas, local contamination of groundwater may occur; this
     would be primarily in areas of soils of very high permeabi-
     lity, high water table, and/or slow moving groundwater.

     Data on intensive farming regions where CH pesticides have
     been used heavily are available from standard sources (e.g.,
     U. S. Census Bureau) and also through the U. S. Department of
     Agriculture, Federal and state agricultural experimental
     stations, agricultural extension services, and the EPA.  The
     data on soils and hydrology can be obtained from the Soil
     Conservation Service, U. S. Geological Survey, USDA, state
     geological surveys,  the Water Resource Department of each
     state, and the Water Resources Research Center of each state.
     The USDA's Agricultural Statistics is a particularly useful
     data source.

B.   Preliminary Correlation Between Organics Found in Drinking
     Water and Specific Pesticide and Fertilizer Uses

     The nationwide occurrence of organic compounds identified in
     drinking water are listed in Table 1-IV-l which follows [96].
     Those which are active ingredients in pesticide formulations
     are listed in Table l-IV-2 and those which are inactive in-
     gredients, such as solvents, are listed in Table l-IV-3.

     The list of compounds in Table 1-IV-l comprise the total or-
     ganics identified in drinking water but are only a small
     fraction by weight of the total organics in drinking water
     [96].

     Many of the chemicals which appear on Table 1-IV-l could be
     chemical or biochemical degradation products of pesticide
     formulations, both active and nonactive ingredients.  There is
     no evidence of fertilizer ingredients.

     The majority of pesticides in drinking water arises from
     agricultural and urban runoff.  A significant number of the
     chemicals listed on Tables l-IV-2 and l-IV-3 are chlorinated
     which is the more persistent category.   To help put this
     matter of organic pesticide correlation with organics in
     perspective it has been determined that for one foot of pene-
     tration of dieldrin residue at a residual level of 20 ppb,
     water must infiltrate from 360 to 480 feet into the soil
     [103].  This throws some light on the likelihood the cor-
     relation which exists for surface water pesticides and or-
     ganics occurring for ground water.

                              44

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                          TABLE 1-IV-l

         Organic Compounds Identified in Drinking Water*
acenaphthylene
acetic acid
acetophenone
aldrin
de ethyl atrazine
behenic acid, methyl ester
benzene sulfonic acid
benzopyrene
benzothiophene
borneol
bromochlorobenzene
bromofonn
bromophenyl phenyl ether
butyl bromide
e-caprolactam
carbon tetrachloride
chlorobenzene
b-chloroethyl methyl ether
chlorohydroxy benzophenone
chloromethyl ether
m-chloromitrobenzene
o-cresol
DDT
dibromobenzene
dibromodichloroethane
1,4-dichlorobenzene
1,2-dichloroethane
dieldrin
di(2-ethyl hexyl) phthalate
dihydrocarvone
di-isobutyl phthalate
1,3-dimethyl naphthalene
2,4-dimethyl phenol
acanaphthene
bladex
chlordene
crotonaldehyde
cycloheptanone
acetaldehyde
acetone
acetylene dichloride
atrazine
barbital
benzene
benzoic acid
benzothiazole
benzy butyl phthalate
bromobenzene
bronodichloromethane
bromoform butanal
butyl benzene
camphor
carbon disulfide
chlordane
1,2-bis-chloroethoxyethane
chloroform
b-chlorethyl methyl ether
chloromethyl ethyl ether
3-chloropyridine
DDE
decane
dibromochloromethane
dibutyl phthalate
dichlorodifluoroethane
dichloroethyl ether
diethyl phthalate
dihexyl phthalate
di-isobutyl carbinol
1,2-dimethoxybenzene
dimethyl sulfoxide
dimethyl phthalate
benzaldehyde
carbon dioxide
1-chloropropene
cyanogen chloride
1,3-dichlorobenzene
*Source:  "Identification of Organic Compounds in Effluents from
          Industrial Sources"
          Prepared for Office of Toxic Substances - EPA
          Prepared by Versar Inc., Springfield, Virginia
          April, 1975, EPA 560/3-75-002
                            45

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 1,l-dichloro-2-hexanone
 dichloropropane
 di-(2-ethyl hexyl) adipate
 diphenyl hydrazine
 p-ethyl toluene
 hexachlorophene
 methyl methacrylate
 pentachlorophenyl methyl ether
 propazine
 trimethyl benzene
 o-xylene
 m-xylene
 alachlor
 butyl octyl maleate
 ethyl acetate
 1,1,1-trichloropropane
 methyl-2,3-dihydroindene
 tetrachlorophenol
 methyl cyclohexane
 diraethoxy acetophenone
 o-phenyl phenol
 tetramethyl benzene
 trichloropropane
 dichloroiodomethane
 bis-(2-ethoxy ethy) ether
 chloroiodomethane
 Acetylene chloride
 isopropanol
 chloroethyl ether
 4,6-dinitro-2-aminaphenol
 dioctyl adipate
 docosane
 eicosane
 ethanol
 ethyl benzene
 cis-2-ethyl-4-methyl-l,3-
   dioxolane
 o-ethyl toluene
 heptachlor
 1,2,3,4,5,7,7-heptachloronor
   bornene
.hexachloro-1,3-butadiene
 hexachloroethan
 2-hydroxadiponitrile
.isodecane
 isoborneol
 isopropyl benzene
 methyl ester of lignoceric acid
 methanol
 methyl benzoate
2,4-dichlorophenol
1,3-dichloropropene
diethyl benzene
m-ethyl toluene
geosmin
o-methoxy-phenol
methyl tetracosamoate
piperidine
simazine
3,5,5-trimethyl-bicyclo-(4,1,0)-
   heptene-2-one
p-xylene
butachlor
dicyclopentaciene
pentachloroethane
2,3-dihydroindene
methyl benzothiophene
ethyl hexanol
ethyl acetophenone
2,6-di-t-butyl-4-methylphenol
butyl benzene sulfonamide
isocyanic acid
trichloropropene
chloral
bromomethane
chloropropane
bromotrichloroethylene
biphenyl
diethyl ether
2,6-dinitrotoluene
dipropyl phthalate
n-dodecane
endrin
ethylamine
2-ethyl-n-hexane
trans-2-ethyl-4-methyl-l,3-
   dioxolane
guaiacol
heptachlor epoxide
hexachlorobenzene
hexachlorocyclohexane
hexadecane
indene
isophorone
isopropenyl-4-isopropyl
   benzene
limonene
methane.
2-methoxy biphenyl
methyl benzothiazole
                             46

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methyl biphenyl
methyl chloride
2-methyl-5-ethyl-pyridine
methyl naphthalene
methyl phenyl carbinol
methyl stearate
naphthalene
nitrobenzene
octadecane
octylchloride
pentachlorophenol
pentane
phenyl benzoate
propanol
propyl benzene
1,1,3,3-tetrachloroacetone
tetrachloroethane
toluene
trichlorobiphenyl
1,1,2-trichloroethylene
2,4,6-trichlorophenol
l,3,5-trimethyl-2,4,6-trioxo-
   hexahydro-triazene
vinyl benzene
3-methyl butanol
methyl ethyl ketone
methyl indene
methyl palmitate
2-methyl propanal
methylene chloride
nitroanisole
nonane
octane
pentachlorob ipheny1
pentadecane
pentanol
phthalic anhydride
propylamine
1-terpineol
tetrachlorobiphenyl
tetrachloroethylene
trichlorobenzene
1,1,2-trichloroethane
trichlorfluoromethane
n-tridecane
triphenyl phosphate
n-undecane
xylene
                            47

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                          TABLE l-IV-2

        Pesticide Chemicals Identified in Drinking Wnter
                     Active Ingredients [94]
acenaphthylene
acetic acid
aldrin
atrazine
(de-ethyl)atrazine
bromoform
carbon disulfide
carbon tetrachloride
chlordane
chloroform
DDE
DDT
1,4-dichlorobenzene
dichlorethyl ether
dieldrin
4,6-dinitro-2-aminophenol
endrin
heptachlor
heptachlorepoxide
1,2,3,4,5,7,7-heptachloronor-
   bornene
hexachlorobenzene
hexachlorocyclohexane
isophorome
naphthalene
pentachlorophenol
2,4,5-trichlorophenol
                                48

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                          TABLE l-IV-3
        Non-Active Ingredients of Pesticide Formulations
                Identified in Drinking Water [94]
acetone
benzene
benzoic acid
camphor
chlorobenzene
o-cresol
dibutyl phthalate
dimethyl benzene (xylene)
2,4-dimethyl phenol
dimethyl phthalate
dimethyl sulfoxide
ethanol
hexachloroethane
1imonene
methanol
(3-methy1-2-butane)
methyl chloride
methyl ethyl ketone
methyl naphthalene
(methylated naphtalenes)
methyleve chloride
nitrobenzene
pentane
propanol
1-terpineol
tetrachloroethane
tetrachloroethylene
toluene
(1,1,1-trichloroethane)
1,1,2-trichlorethylene
trichlorofluromethane
xylenol
                                49

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     ingredients should not be considered comprehensive not only
     because of the lack of information on degradation products
     but also because of the possibility of the presence of un-
     reacted pesticide raw materials.   In addition many of the
     pesticide ingredients are also potentially derived from in-
     dustrial, medical, and natural environmental sources.

     It should not be inferred from this correlation presentation
     that the presence of pesticide chemicals and/or their degra-
     dation products in drinking water is explained by pesticide
     pollution of groundwater nor is the inference intended that
     the presence of these chemicals in drinking water does or
     does not lead one to the conclusion that they can be expected
     to be found in groundwater because of the characteristic
     flow patterns which relate groundwater and surface water.

C.   Laboratory Testing Procedures for Pesticides

     There is a definite need in some areas for laboratory work to
     supplement the statistical data available.  This is especially
     true in areas where edaphic and hydro-geologic factors are
     unique and conducive to pesticide transport into groundwater.
     Areas where data is marginal but show a need for further
     investigation should be sampled.

     Analytical methodology for determination of pesticide residues
     and their metabolites and degradation products in environ-
     mental samples is in a state of constant development with
     rapid advances in analytical chemistry and instrumentation.
     There are several analytical methods available for pesticide
     residue analysis.  At present, the most accurate and most
     advanced method available is gas-liquid chromatography.   In
     the discussion of laboratory analysis, gas chromatography will
     be considered as a prime tool for pesticide residue analysis.
     If and when analysis warrants other methods to supplement gas
     chromatography, these more suitable methods should be em-
     ployed.

     All methods and procedures must follow the procedures de-
     scribed and published in the Association of Official Analy-
     tical Chemists (AOAC) [23].  The Food and Drug Administration,
     Environmental Protection Agency,  and the Agriculture Research
     Service of the USDA all follow the AOAC.  By strictly fol-
     lowing the methodology of AOAC the data obtained will be
     within the limits and variables of data published by the above
     mentioned agencies.  The procedures for processing and analyz-
     ing samples are given in the AOAC manual.  Laboratory testing
     procedures are highlighted below.
                           50

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Gas Chromatography.  It is necessary to use preparative thin
layer chromatography to separate and isolate pesticide resi-
dues from other contaminants.   A pesticide residue separated
from other contaminants should be analyzed using gas-chroma-
tography equipped with electron capture detectors for its
quantitative determination.

Injection technique and injection is one of the important
starting functions of the gas chromatographic analysis.  It is
important that both standard and sample solutions be handled
in precisely the same way in order to minimize errors caused
by variable response of the instruments.  It is also important
that sample injection be carried out at least twice, as should
be standard, to minimize errors.

Only glass columns should be used since they minimize de-
composition.  These columns must be conditioned at an elevated
temperature before use.  All columns will be standardized with
various standard samples to check their efficiency and reli-
ability.

Electron capture detection with a tritium source should be
employed since these types of detectors are most accurate.
When necessary, the tritium foils can be changed easily.

The areas under the peaks of the sample graphs and the stand-
ard graphs must be calculated in an identical manner so as to
minimize measuring errors.

There is probably no need for nitrate determination in the
laboratory.  Sufficient published data is available at present
to define and assess the problem.
                                                   >
Time and Temperature.  Samples should be analyzed as soon as
they are received in the laboratory.  This will minimize
physical and chemical changes that may occur.  A waterless
sample must be stored below 0°C in airtight glass bottles.
Since light has an effect on pesticides and they do degrade
under exposed light, samples must be kept in the dark and in
amber colored glass bottles.  It is necessary to avoid plastic
or metal containers for storing samples, since they affect the
pesticide concentrations or cause contamination. The caps used
on the amber storage bottles should be equipped with teflon
liners to prevent contamination.

Extraction Methods.  A standard method of extraction should be
employed to get the sample free from water and soil particles.
Standard techniques such as blending or tumbling of the sam-
ples and solvents for rapidity and ease of handling
                       51

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          should be employed.  A mixture of relatively polar and non-
          polar solvents has to be employed to get a thorough extraction
          of the pesticide residue.

          Cleanup Procedure.  It is necessary to use the standard clean-
          up procedure before GLC analysis.  This should be done for two
          reasons.  First, a cleaned sample will give specificity and
          ease of analysis, and secondly it will prevent undue con-
          tamination of gas chromatograph injection ports, columns, and
          detectors.

V.   ECONOMIC IMPACT OF GROUNDWATER CONTAMINATION ABATEMENT

     A.   Introduction and Overview

          The approach which is proposed to the evaluation of the econo-
          mic effects of the regulation of groundwater contamination is
          related to cost-benefit analysis.  This interconnection is
          important for two reasons.  One is the legitimacy conferred on
          the suggested procedure through its compatibility with the
          generally-used and officially-suggested cost-benefit tool.*
          The second reason is that the cost-benefit framework is a
          useful one for clarifying the assumptions underlying the
          suggested economic impact analysis.  Explanation of these
          interrelationships and assumptions should therefore introduce
          the economic evaluation of the regulation of groundwater
          contamination.

     B.   Cost-Benefit Analysis

          Cost-benefit analysis is the generally-accepted current prac-
          tice used for the economic evaluation of public programs.  As
          Mishan argues, cost-benefit analysis is not fundamentally
          different from the accounting for profitability employed by a
          private firm when considering an investment in the production
          of goods or services.  Rather, the same sort of question is
          being asked about a wider group of people—who comprise so-
          ciety—and this question is being asked more searchingly.
          Instead of asking whether the owners of the enterprise will
          become better off by the firm's engaging in one activity
          rather than another, the economist asks whether society as a
          whole will become better off by undertaking this project
          rather than by not undertaking it, or by undertaking, instead,
          any of a number of alternative projects [36].

"*Senate Document 97 encourages the use of cost-benefit analysis in
public decision-making.
                                52

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     A critical part of any economic evaluation is the careful
     delineation of the relevant costs and returns.   James and Lee
     categorize the benefits and costs associated with water re-
     source planning [48].   In addition to the (a) tangible primary
     benefits gained directly from project-produced goods and
     services—examples are irrigation water and flood control—
     James and Lee categorize benefits as (b) tangible secondary,
     including gains accruing to output-receiving and input-pro-
     viding industries interrelated with the directly-affected
     industry groups (c) tangible employment benefits (d) tangible
     public benefits and (e) intangible benefits. Tangible employ-
     ment benefits are the new jobs created to construct, maintain
     or operate the project.  Tangible public benefits include such
     often serendipitous gains as economic stabilization, income
     redistribution, and regional development.

C.   Intangible Benefits

     Intangible benefits are consequences which cannot be assigned
     market value and which must be evaluated on a judgmental
     basis.  Examples are the saving of life, improvement of health
     and the preservation of a desirable environment.  Because
     these benefits involve value judgments, authors like James and
     Lee typically have less to offer about assessing them.

     The above list of benefits shows the disadvantages of standard
     cost-benefit analysis for the assessment of the regulation of
     groundwater contamination.  The benefits from such regulation
     are primarily intangible.  They are also future-oriented.
     Groundwater typically moves slowly and is contaminated as a
     result of a long-term and gradual process.  Once contaminated,
     nature's ability to cleanse the water is also slow  (or even
     non-existent).  This long-term situation means many,of the
     most significant benefits from regulation of contamination
     accrue to future populations rather than to the current so-
     ciety.

     Intangible benefits from maintaining pure groundwater are
     quite complex as well as very important.  Economists like
     Weisbrod, Cicchetti, Freeman, Aaron and Fisher have identified
     at least four different "option values" for such forms of
     regulation.  One of these, "option demand," is the value to  .
     individuals of having future access to a resource for economic.
     uses.  A second option value, "existence demand," is the
     demand of people who do not ever plan to use a resource, but.
     who derive value from knowing it is preserved in its natural  •
     state.  "Bequest demand," the third option value, is a derivative

                              53

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    . of option demand in which individuals wish to guarantee the
     option of using a resource for their heirs.  Finally, there is
     "safety or hazard-aversion demand" from individuals who want
     to avert the risk of damage to their health.   -

     All four option values result from the regulation of ground-
     water contamination.  However, it is doubtful these values
     could ever be separated empirically, much less assigned a
     quantitative value.  Furthermore, if one were to attempt to
     measure the various benefits as outlined by James and Lee,
     regulation of the contamination of groundwater would.usually
     end up with a negative quantitative benefit value and a set of
     qualifying statements.  Such a statement of benefits runs a
     risk of misinterpretation by anyone who does not read the
     report with care.

D.   Economic Impact Analysis

     Negative benefit values do not invalidate" cost-benefit analy-
     ses, but they do make such analyses awkward to handle. Con-
     sequently, economic analysts often shift away from cost-
     benefit analysis in such cases, and use economic impact
     analysis instead.  Economic impact analysis starts with the a-
     priori presumption that the benefits are great enough to
     justify the public program.  The goal of the analysis becomes
     the assessment of the costs of the program.  Costs are not
     restricted to the direct and ^associated costs of the* project's
     construction as they are in cost-benefit analysis. Rather,
     costs are defined to be the costs of cost-benefit analysis
     plus any quantifiable negative benefits.  A major purpose of
     doing an economic impact analysis is to allow the initial
     assumption of the worthiness of the public program to be re-
     evaluated via a more informed judgment.

     It is suggested here, and later in the "plan" section, that
     economic impact analysis best suits the economic analysis of
     the regulation of groundwater contamination.  Such an analysis
     provides a suitable analytical context which is consistent
     with cost-benefit analysis and which is clear in interpre-
     tation.  The framework of the approach emphasizes the central
     and a-priori nature of the judgment made about the intangible
     benefits and it encourages the re-evaluation of -this judgment.

     In the suggested economic impact analysis, costs would be
     defined as primary and secondary.  Primary costs would be
     those incurred by the directly-regulated firms or households
     in complying with the.regulation.  Secondary costs are the
     negative secondary, employment and public benefits expressed
     as positive quantities.  Any positive tangible benefits
                           54

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     would,  of course,  be subtracted from these secondary costs.

     The costs used in the impact analysis would be expressed as
     marginal values.   Only the increase due to the introduction  of
     the regulatory program would be measured.   This allows the
     cost to be viewed as an impact.  Also, it  often simplifies the
     technical derivation of the cost coefficients.

E.   Primary Costs

     Some of the techniques which could be used to measure primary
     costs at the firm or household level are partial budgeting,
     mathematical programming and economic engineering analysis.
     These techniques have a comparative advantage over other
     econometric methods at this level of dis-aggregation.  Partial
     budgeting has the additional advantages of simplicity and un-
     expensiveness; however, its use depends on the availability  of
     good accounting data.  Mathematical programming can yield the
     same type of answers as budgeting plus additional results, but
     this more formal method is better suited for optimizing re-
     turns than for assessing impacts.  Economic-engineering—
     called unit operation analysis by engineers—has an advantage
     whenever the costs of new productive enterprises are needed
     and the necessary accounting data is not available.

F.   Secondary Costs

     Primary costs would have to be determined at the firm or
     household level and then aggregated to a regional level by
     using firm and household distributions.  Secondary costs can
     be measured at the regional level via such techniques as
     input-output analysis, economic base analysis, social ac-
     counting techniques or by consumer and producer surplus mea-
     sures of social welfare.  Input-output analysis and economic
     base analysis focus on the costs incurred by industries that
     are economically linked to the regulated firms and households.
     The consumer-surplus oriented method focuses on the impacts on
     final consumers and on the suppliers of labor.  All of these
     more formal methods are time-consuming, expensive and data-
     demanding.  Yet they do not always incorporate all the secon-
     dary cost factors.  As a consequence, they should be used only
     when a particular secondary cost is so significant that care-
     ful formal measurement is necessary.

     The inter-relationships of the various measurement techniques
     will be more clearly specified in the tasks outlined later.  It
     should be noted, however, that these tasks stress a careful
     and sometimes elaborate delineation of which primary and
                           55

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          secondary costs are important as the quantification .of a
          particular cost.  Also, the proposed tasks stress simplicity
          of measurement, whenever possible, with the more complicated
          and expensive methodologies .relegated to a back-up role. The
          keynote.criterion of the proposed procedure is a uniformly
          accurate measurement of all significant costs.  Such an ap-
          proach should adequately serve the need for an economic eva-
          luation of the regulation of groundwater contamination.

VI.  GROUNDWATER FLOW MODELS

     A.   Introduction and Overview

          Porous soil media is a complex matrix.  Such a matrix may be
          viewed as a solid body with irregular interconnected voids.
          These interconnecting voids or pore channels are of primary
          interest in understanding the flow of miscible fluids in
          porous media.  There are two approaches to the study of flow
          through porous media; the investigation of the particular
          porous media matrices that exist in nature, or the mathe-
          matical modeling of various types of matrices.  Experimen-
          tally, the investigations would be limited to a small number
          of different porous media matrices; with theoretical model
          studies many different possible porous media structures could
          be investigated.  However, the validity of the theoretical
          model must be assured through experimental verification.

          Experimental techniques have been carried out to a-high degree
          of refinement.  Generally, a .given substance is.injected into
          the medium, and then the medium is sampled at various, depths
          by cutting into it or extracting liquid from it for analysis.
          Theoretical modeling includes two distinct.approaches  (a) the
          deterministic model, and (b) the probabilistic model.  The
          deterministic model is based on the solution of the basic
          differential equations for viscous fluids subject to dis-
          persion and adsorption.  The probabilistic models on the other
          hand concentrate on the statistical character of the porous
          media.  The present state of the art of analytic - numerical
          methods for solving particular flow problems in porous media
          flow is to solve a set of coupled nonlinear partial diffe-
          rential equations with appropriate boundary and initial, etc.
          conditions.

          In dealing with the movement of pesticides and nitrates from
          the soil surface down to the water table one must look at
          flows in the unsaturated region as well as flows in the satu-
          rated region..  The unsaturated-region consists pf the
                               56

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     layers overlying the groundwater table;  in this region the
     soil pores are filled by two materials - water and air.   Water
     movement in these layers consists of three phases -solid
     mineral grains, fluid water and gaseous air.   The transport of
     water is more complicated in this region than it is in the
     saturated region (region below the water table) where the soil
     pores are completely filled with water.

B.   Unsaturated Flow

     In the unsaturated region the infiltration process is a com-
     plex phenomenon.  It consists of a hydraulic transfer of
     water, accompanied by extraction, and subsequent retention, of
     liquid by the sediment as the infiltrating liquid passes
     through it.  For example, the water retention in gravel is
     negligible, while in sands the retention is due primarily to
     capillary action.  In clays, however, the retention, which is
     essentially an osmotic pressure mechanism, is very large.  The
     shrinkage cracks in a dry clay result in large amounts of
     water being transmitted.  This lasts until the dry matrix has
     swelled and closed up, at which time the clay ceases to trans-
     mit appreciable amounts of water.  From these considerations
     it appears that sediments or soils consisting of gravel, sand
     and silt are, in addition to fissured rocks, make up the
     principal soil formation capable of transmitting substantial
     volumes of water and contaminants into groundwater basins.

     As .stated earlier, the mathematics of flow in the unsaturated
     media is extremely complicated.  In only a few cases have
     solutions been obtained.  These solutions were obtained using
     one-dimensional, two-dimensional, and simplified models.
     Little is known of the adsorption mechanism of pesticides on
     soil matrices.  Experimental studies indicate various amounts
     of CH are leached from different soils. In summary, knowledge
     of moisture movement in the unsaturated zone is not advanced
     to the stage where one can accurately predict transient mois-
     ture changes under actual field conditions; complete models
     that accurately predict migrations of various pesticides and
     nitrates in the unsaturated zone have not been fully deve-
     loped.

C.   Saturated Zone

     The theory of  dispersion of miscible fluids in porous media
     has received considerable attention in  recent years.  Interest
     in dispersion  has resulted from water quality considerations
     of waste disposal operations,  sea water intrusion and seepage
     from canals into aquifers.
                            57

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Hydrodynamic dispersion or miscible dispersion is a spreading
phenomenon.  Experiments show that when a flow containing a
certain mass of solute (known as a tracer) is moving, the
tracer usually spreads and occupies an ever increasing portion
of the flow domain, beyond the region it Is expected to occupy
according to the average flow alone.  The mixing of the tracer
mass with the remaining portion of the flowing liquid is a
transient, irreversible process. Hydrodynamic dispersion is
the macroscopic outcome of the actual movements of the in-
dividual tracer particles through the soil pores and also the
outcome of various physical and chemical phenomena that take
place within the pores.

The two basic transport phenomena involved in dispersion are
convection and molecular dispersion.  The two basic elements
of convection or mixing are the flow (variation in local
velocity, both in magnitude and direction) and the geometry of
the pore system.  Molecular dispersion is a mass transport
phenomenon resulting from variations in the tracer concent-
rations within the liquid phase.  The interaction between the
solid surface of the porous matrix and the liquid may take
several forms:  adsorption of tracer particles on the solid
surface, deposition, solution, ion exchange, etc. [38].  All
of these phenomena, as well as chemical reactions within the
liquid, may cause changes in the concentration of the tracer
in the flowing liquid.

Because of the complexity of the dispersion-adsorption pheno-
menon in porous media, no general model has been formulated
and solved.  Solutions to various specific miscible displace-
ment problems in porous media have been obtained by a number
of investigators.  Common to most of these studies is the
basic assumption that the concentration at one boundary is in
the form of a step function; that is, the concentration of the
tracer to be introduced at one boundary changes instantane-
ously from zero to some predetermined value and is maintained
thereafter (conservative model). In addition, most models
assume that convection and dispersion are the principal fac-
tors in mass transport while other mass transport mechanisms
are considered insignificant and therefore neglected.

The model studies which have been performed by various in-
vestigators can be placed into one of two categories:  (a)
dispersion with no adsorption, and  (b) dispersion with ad-
sorption.  A brief summary of each type of modeling is given
below.
                58

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D.   Dispersion With No Adsorption

     Some of the early analytical solutions for longitudinal dis-
     persion within a semi-infinite non-adsorbing porous media were
     obtained by Ebach, et al (1958) and Ogata, et al (1961). In
     both cases, a steady undirectional flow was assumed; the Ebach
     study assumed an input concentration that is a periodic func-
     tion of time while the Ogata study considered the   1
     input concentration to be a constant.  Hoopes, et al (1965)
     investigated the problem of dispersion in radial flow from a
     fully penetrating well operating in a homogeneous, isotropic
     confined aquifer.  The study was directed primarily at dis-
     persion from injection wells where the solute was non-ad-
     sorbing.  Shamiz, et al (1960) obtained analytical solutions
     for longitudinal dispersion in a semi-infinite non-adsorbing
     layered medium.  In their model, the flow was assumed to be
     perpendicular to the layers of longitudinal dispersions and
     parallel to the layers for the lateral dispersion case.  In
     both cases the input concentration was assumed to be constant
     and adsorption was neglected.  Bruch and Street  (1966) in-
     vestigated the flow in a semi-infinite non adsorbing porous
     media subject to longitudinal and lateral dispersion.  As in
     the previous studies, it was assumed that there  is steady
     undirectional flow which was subject to a constant concent-
     ration input.

E.   Dispersion With Adsorption

     Nielsen, et al (1962) presented several examples of break-
     through curves in which interaction between the  liquid and the
     solid phase has taken place.  Several theoretical models have
     been suggested for dispersion with adsorption.   Lindstrom, et
     al  (1967) examined various solutions to the dispersion equat-
     ion subject to linear adsorption under input conditions of
     continuous flux and plug type.  Ogata (1964) obtained an
     analytical solution to the one dimensional dispersion equation
     subject to linear adsorption. Similar solutions  were also
     obtained by means of the integral transform method by Cleasy
     and Adrian (1973).  Banks and Ali (1964) presented an analy-
     tical solution to the dispersion equation subject to a linear
     adsorption isotherm. The flow was considered to  be steady and
     one-dimensional under a constant concentration input.  The
     case of non-linear adsorption was also investigated subject to.
     no  dispersion.  Gershon, et al  (1969) studied the effects of
     boundary conditions of various models on tracer  distribution .
     in  flow through porous media.  A solution for one-dimensional •
     dispersion subject to a semi-infinite adsorpting porous media
     was presented.
                             59

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     Numerical solutions of the dispersion equation for different
     adsorption equilibriums was reported by Lai, et al (1972).
     Solution to the one dimensional dispersion equation subject to
     non-linear adsorption was given by Tagamets, et al (1974), and
     by Gupta, et al (1973) for a bilinear rate of adsorption.
     Solution of the dispersion equation with adsorption was also
     reported by Rubin (1973).  A summary of some analytical so-
     lutions to the dispersion equation is given by DeWiest (1969)
     and Ogata (1970).

F.   Summary of Dispersion Models

     In general, the available analytical solutions of.the dis-
     persion equation are for simple one dimensional flow with
     constant concentration input.  In all of these cases adsorp-
     tion has been neglected or assumed linear.  The available
     numerical techniques provide approximate solutions for dis-
     persion with non-linear adsorption in one dimensional flow.
     All of the above cases are ideal, i.e. homogeneous, isotropic
     soils, constant initial concentration, and well defined ad-
     sorption isotherms.  Unfortunately, conditions in nature
     cannot be duplicated by the models; soils are not homogeneous
     and isotropic, concentration varies with time and space, and
     the adsorption isotherms of many pesticides are not well
     known.

C.   Regional Models

     A physical-chemical model for predicting the movement of
     contaminants in an isothermal groundwater system  in which
     there are no chemical reactions was developed by  Bredehoeft
     and Finder  [5, 6].  The mass transport equation and the equa-
     tion of motion have been coupled and solved numerically for a
     saturated groundwater system.

     The authors tested their model by analyzing the movement of
     contaminants in the principal aquifer at Brunswick, Georgia
     [59, 60].  The particular contaminant studied was salt water
     contamination  (chloride) and the model was used to predict
     future chloride distributions.  The model was calibrated using
     data available due to extensive geohydrological investigations
     conducted by USGS at Brunswick.  The use of this.model to
     predict changes in ground water quality is limited.  The
     complete physical - chemical description of moving groundwater
     must include chemical reactions in a multicomponent fluid and
     requires simultaneous solutions of the differential equations
     that describe  the transport of mass  (including dispersion,
     adsorption) momentum and energy in porous media.  Finder  [55]
     used the Galerkian method in conjunction with the finite
     element method to simulate the movement of groundwater con-
     taminants.  The mathematical model was used to simulate  the
                          60

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movement of a plume of chromium contaminated groundwater on
Long Island, N.Y.  The two dimensional model considered poro-
sity and hydrodynamic dispersion to be the principal aquifer
properties affecting mass transport.  Values of longitudinal
and lateral dispersion were estimated based on tests conducted
on similar material due to lack of actual data.  Adsorption
was neglected in this study.  Calibration of the model was
based on historical record of chromium distribution and was
used to predict the location of the plume in future years.
The model requires extensive data and is limited to cases
where the point where the effluent concentration enters the
aquifer is known.

In 1974 a digital computer program  [22] was developed to esti-
mate concentration of total dissolved solids (TDS) of ex-
tracted water from a multiaquifer groundwater basin.  The
model considered salt input from natural sources due to man's
uses of water:  domestic, industrial, and agricultural.  The
model was tested on the Santa Clara - Calleguas area in Ven-
tura County, California.  That area was selected because a
water quality model was already available for the area and
could be used to simulate groundwater movement.

The quality model considers six inflows such as rainfall
infiltration, percolation, etc. and three outflows:  sub-
surface outflow, extraction and consumption by phreatophytes.
The model does not account for chemical reactions, adsorption
of dispersion.  It is basically a tool for management to
predict TDS concentration subject to different inflow para-
meters.

During 1974 the U.S. Geological Survey (USGS)  [61,53] com-
pleted a study, wherein a conservative model was developed.
The linear mathematical model used  in the USGS study is an
idealized representation of the San Juan Valley groundwater
basin.  It describes in concise quantitative terms the re-
sponse of the groundwater system to various conditions of
stress or development.  Once such a quantitative response has
been obtained, the model can be used to facilitate an under-
standing of the hydrologic system and aid in determining how
climate, geology, and man influence the groundwater basin.
The model was developed according to the theory and analytical
approach developed by Finder and Bredehoeft  [5],  (1968)  [6].

In order to use this mathematical model as a predictive tool .
it must first be calibrated.  Model calibration is accomplished
                       61

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by combining, in the model, hypothetical distributions of
transmissivity and specific yield values with sets of known or
estimated groundwater flow conditions.  The correct, or cali-
brated, combination of aquifer parameters and flow conditions
is determined when model-generated water levels approximate
historical water levels within some predetermined limit of
accuracy.

Recently the Agricultural Research Service of the USDA pub-
lished an Agricultural Chemical Transport Model (ACTMO) [25].
The objectives of this model are to predict the concentration
and amount of the chemical in the runoff water and in the
sediment at the watershed outlet, and to predict the location
and concentration of chemicals that are leached and moved
spatially through the soil of the watershed.  The model in-
cludes such management options as the time, rate, and type of
chemical applied, changes in crop pattern, and tillage prac-
tices.  To facilitate application, topographic, soil, and land
use maps of the watershed are used to estimate model para-
meters.  The model's authors assume that published, data from
the field and laboratory can be used for estimating the chemi-
cal interaction with the soils and water.

The model is divided into three submodels:  a chemical, an
erosional, and a hydrological submodel.  The erosion submodel
receives data from the hydrology submodel while the chemical
submodel receives data from both the hydrological and ero-
sional submodels.  This separation facilitates the interchange
of other chemical, erosional or hydrological submodels and
modifications.  Objectives of the initial effort were to
achieve an operating version of ACTMO for certain limited
conditions.

Unfortunately, ACTMO which is a dynamic model, is aimed pri-
marily at surface water runoff from a specific farm.  However,
it could be modified to reflect the groundwater recharge
problem, and by manipulating and adding parameters, it could
be used over large section of soil regions.

A model, called the Pesticide Transport and Runoff  (PTR)
Model  [12] was developed by the EPA.  This model is primarily
a surface model, but like ACTMO it gives results adaptable to
groundwater needs.  Four pesticide storage zones with assigned
depths within the soil profile are assumed:, surface zone,
upper zone, lower zone, and groundwater zone.  The assumed .
zone depths are necessary to specify  the mass of soil involved
in the pesticide-soil interactions.

The PTR Model estimates the loss of pesticides from the land
surface by simulating the mechanisms  of surface runoff,

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sediment loss, pesticide adsorption-desorption, and pesticide
volatilization and degradation.  There are various loss
mechanisms and submodels included within the PTR Model. The
hydrologic submodel is responsible for the determination of
surface runoff and soil moisture storage.  The sediment loss
submodel estimates sediment production from the land surface
based on input rainfall and surface runoff provided by the
hydrologic model.  The division of applied pesticide among the
various phases (adsorbed, dissolved, and crystalline) is
determined by the pesticide adsorption-desorption submodel.
This submodel, in conjunction with the hydrologic and sediment
loss submodels, determines the amount of pesticide removed
from the land surface by surface runoff and sediment loss.
This model also considers the loss of pesticides by vola-
tilization and degradation.

Another recent model  [14] developed for the EPA describes
pesticide movement through soils.  In this work a numerical
simulation procedure for describing the simultaneous transport
of water and adsorbed and nonadsorbed solutes was developed
and evaluated.  The combined effect of convection, adsorption-
desorption, and dispersion (diffusion and mechanical dis-
persion) were considered as well as a correction for numerical
dispersion in the finite difference solution of the solute
transport equation.  Experimental laboratory and field data
were used to evaluate the suitability of the two numerical
solutions to describe the movement of each phase.  Adsorption
and desorption was also studied for several herbicide-soil
systems.  Several adsorption models were considered and eva-
luated in the solute  transport equation.  However, a numerical
solution has not been developed and tested for simultaneous
transfer of water and adsorbed solutes in a soil.
                                                    >
It appears that, given reasonable time to develop or modify
subsections from existing models, a working model could be
developed which would describe the percolation of nitrates
and/or pesticides through various soil types and into  ground-
water.  Although such a model can be developed, there  are  two
obstacles which potentially limit the usefulness of the model:
(a) the amount of data available for input into the model; and
(b) the surface area  over which the model can be applied.  The
PTR and ACTMO models  can now characterize only a few acres of
surface, which indicates the degree of difficulty still to be
met in modeling larger areas.

The EPA laboratory at Athens,  Georgia, is developing a water
basin study using an  area of approximately twenty square miles
in Iowa [103].  This  region will be instrumented and

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modeled for surface and subsurface runoff evapotranspiration,
rainfall, crop cover, soil porosity and moisture, pesticide
(and fertilizer) applications, rates of denitrificatibn, etc.
An estimate will be made as to How much water percolates
through the soil as part of the materials balance, but a
measurement of the effects on groundwater as such are not
projected at present.  It would seem feasible that this multi-
year study could be modified to include considerations of
groundwater, and the model extended to include this dimension.
Putting this project in perspective, one of the intents of
this study is to give the EPA and the manufacturers of pes-
ticides a "standardized" method for calculating the potential
impact of a pesticide on surface waters before registration is
granted.

The U.S. Geological Survey and certain contracting firms have
developed models [60] for the U.S. Energy Research and De-
velopment Administration (formerly the U.S. Atomic Energy
Commission) which characterize the transport of radioactive
and chemical wastes from buried materials.  Reeves and Duguid
[16,58] have developed a two-dimensional transient model for
water movement through saturated-unsaturated porous media
which can cope with multi-layered geologic formations.  This
model uses the Galerkin finite-element method.

With these point source models available, it appears feasible
that with additional submodels included, a feedlot (or septic
system) could be adequately modeled to estimate groundwater
impacts.

Many other models have been developed and come to our atten-
tion, but an extensive evaluation of each model at this point
is not in order.  Such' an effort, however, has been assigned
by EPA (Ada, Oklahoma) to the Commission on Simulation Mo-
deling of the Scientific Committee on Problems of the Environ-
ment, headed by Drs. Frenkiel and Munn  [64]. This project,
titled "Evaluation of Existing Groundwater Basin Management
Models," is funded in part by EPA under project control number
R803713-01.  This project is directed to the EPA program
catalogue number and title 66.505 Water Pollution Control-
Research Development and Demonstration. This year long effort
is expected to be completed in late Spring-early Summer of
1976.

The objective of this study is to evaluate existing ground-
water basin models in order to judge the state of knowledge
and state of the art in this,complex art-technology.  The
intent is to provide guidelines for future modeling develop-
ment work to insure a sound and logical baseline.  Indirectly,

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the project may provide guidelines for optimizing the design
of monitoring networks.

It is,strongly suggested that there be a high level of inter-
change between this committee and the EPA task force concerned
with groundwater modeling efforts in order to more rapidly
implement the findings of other groups already working in this
field.
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                    THE IMPACT OF INTENSIVE
                   APPLICATION OF PESTICIDES
                AND FERTILIZERS ON UNDERGROUND
                     WATER RECHARGE AREAS
                    WHICH MAY CONTRIBUTE TO
                    DRINKING WATER SUPPLIES

                           Section 2

         Approaches For A More Detailed Investigation
I.    INTRODUCTION

     This study has considered major agricultural practices with regard
     to their possible adverse impact upon groundwater recharge areas.
     Information has been gathered from many sources including lite-
     rature search, interviews, personal communications and review of
     other related studies and investigations.   In the light of current
     knowledge, it is apparent that all of the  complexities and inter-
     relationships of the many facets of groundwater pollution are not
     yet fully comprehended.

     Therefore, a set of tasks has been formulated which illustrates
     an approach to better understand the total problem and would pro-
     vide a basis for judging the need for measures of abatement and
     control.  These tasks and any further work on the problem will
     be considered within the context of competing priorities for ful-
     filling the charges under the Safe Drinking Water Act.

     These tasks, which could be carried out in a period of about fifteen
     months, have been carefully defined to avoid duplicating efforts
     completed or in progress elsewhere.  A considerable effort is
     already underway at various institutions pertaining to the broad
     topic of intrusion of toxic substances into groundwater from the
     use of such chemicals and also from the operation of feedlots and
     septic systems.  The related problem (not  dealt with in this study)
     of saline buildup, in connection with irrigation practices, is also
     under extensive investigation.  The results of these studies will
     provide inputs to the various tasks described here below.

     Some tasks do complement work already carried out, but are included
     here in order to broaden or fill-out these other projects.  Tasks
     which require very long  term efforts, even though potentially
     valuable, have not been  included; also projects of marginal payoff
     have been omitted.  A set of econometric tasks, in which the costs
     and rewards of optimal corrective measures would be evaluated,
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      illustrates an approach to defining the financial impact and/or
      justification of any recommendations ultimately considered by the
      Agency.

      Some of the proposed tasks are common to, or impinge upon, topics
      under consideration, whereas others are germane only to specific
      components, such as pesticides, fertilizers, feedlots, etc.   The
      presentation, therefore, is structured into "activity streams"
      (Figure 2-1-1) in which the investigations may be conducted con-
      currently.  Four major subject areas are considered:

           1.   Nitrates
                o    Fertilizers
                o    Feedlots
                o    Septic Tanks
           2.   Pesticides
           3.   Economic Impacts
           4.   Modeling and Simulation

      The "general" activity stream (Tasks G-l, G-2, G-3, et seq)  is
      designed to generate basic information relatable to all three
      sources of nitrates and to pesticides.  A separate activity stream
      is then pursued for fertilizers (Tasks FR-1, etc.) feedlots (Tasks
      FE-1, etc.), septic tanks (Task S-l, etc.), and pesticides (Task
      P-l, etc.) and finally all five streams are brought together for
      the economic impact (Task E-l) and modeling (Task M-l) activities.

      In the following pages, the objectives, scope and technical ap-
      proach to each set of tasks are described.  To support and illu-
      minate these descriptions, a detailed discussion of each subject
      area and the present state of knowledge in each is given in a
      series of appendices to the plan.

II.   GENERAL

      A.   Task G-l

           Objective:  To identify and map those areas of the country
           which may be vulnerable to groundwater contamination from
           agricultural practices.

           Scope;  The nation's systems of groundwater reservoirs are
           influenced by climate, soil characteristics, depths of im-
           pervious layers, water tables, and other factors.  Those areas
           in which major productive aquifers occur, i.e., aquifer whicfi
           can yield more than 50 gallons of water per minute to the
           public water supplies are to be located and identified, in
           terms of their vulnerability to contamination.
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00
       FEEDLOTS
       FERTILIZERS
       GENERAL
       PESTICIDES
       SEPTIC TANKS
RECOMMENDED
 MEASURES
    FOR
  CONTROL
                                               Figure 2-1-1   Activity Streams

-------
     Approach;  From data available through such agencies as the
     U.S. Geological Survey (USGS), State Water Resource Research
     Centers, U.S. Department of Agriculture (USDA), U.S. Environ-
     mental Protection Agency (EPA) and others, a map will be
     prepared to show those areas where public water supply is
     drawn from groundwater reservoirs which are most vulnerable to
     contamination by virtue of being overlain with thin or sandy
     soils, highly fractured rock or by having relatively high
     water tables.
B.   Task G-2
     Objective;  To define and map predominant agricultural acti-
     vities practiced in the vulnerable areas identified in Task G-
     1.

     Scope;  Agricultural activities on the land determine the
     nature and extent of possible groundwater contamination. The
     range of activities in areas of productive aquifers with
     vulnerable edaphic and geologic characteristics will be iden-
     tified.

     Approach;  A map of agricultural activity regions will be
     superimposed on the vulnerable areas map prepared in Task G-l.
     This will enable the crop producing and cattle feeding areas
     of the country to be related to groundwater supply and the
     regimes of pesticides and fertilizer applications and feedlot
     operations to be determined.
C.   Task G-3
     Objective;  Within the vulnerable areas, to compare available
     water quality data from productive aquifers with predicted
     values obtained from Tasks G-l and G-2.

     Scope;  Groundwater quality data, while imcomplete, is avail-
     able from several sources.  These data can be used as a bench-
     mark to measure the accuracy of the regimes used in Task G-2
     for predicting groundwater contamination.

     Approach;  A review of groundwater data quality files for
     areas in which intensive agriculture is practiced within the
     vulnerable areas is a priority project task.  Data of this
     type is available through the U.S. Geological Survey  (USGS),
     state Water Resource Research Centers, U.S. Bureau of Census,
     U.S. Department of Agriculture (USDA), U.S. Environmental
     Protection Agency (EPA), Soil Conservation Service (SCS),

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          state Agricultural Extension Services, Land Grant College's
          agricultural research programs, and U.S. Army Corp of Engi-
          neers.

          These data will be compared to the effects of nitrates and
          fertilizers on groundwaters from known agricultural practices
          in the vulnerable areas, as calculated in the previous task.
     D.   Task G-4
          Objective;  To determine whether or not "best" agricultural
          practices can be used to abate groundwater problems.

          Scope;  Up-to-date scientific knowledge and procedures are
          used in the management of many farms, particularly those
          operated as large corporate entities.  The effectiveness of
          those practices, in areas of groundwater contamination, will
          be evaluated and compared to the less structured procedures
          used by the individual farm operator.

          Approach;  In each vulnerable area, an "economic" farm will be
          selected, if possible, and the procedures and extent of use
          and control of pesticides and nitrates on that farm deter-
          mined.  The groundwater quality of these areas will then be
          compared to areas in which no "economic" farm is operated.
          Soil, water tables, and geologic characteristics will be taken
          into consideration in the subsequent evaluations.

III. NITRATES

     A.   Fertilizers

          1.   Task FR-1

               Objective;  To determine the degree to which nitrate
               contamination of groundwater is attributable to agri-
               cultural application of fertilizers. [It may be possible
               to estimate how much nitrate in groundwater derives
               directly from fertilizers and how much from plant decay,
               nitrogen fixation, animal wastes and septic systems by a
               technique* using isotopes of nitrogen which are indi-
               cators—to a degree—of the nature of the source.]

*This technique has been developed at Washington University, St. Louis,
Missouri.
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Scope;  The areas of investigation are limited to those
in which there is intensive farming and high rate of
nitrate fertilizer application.  Regions with deep aqui-
fers and low recharge levels need not be considered.
Aquifers which can yield more than 50 gallons of water
per minute to public water supplies are of primary con-
cern.

Approach:  It is recognized that nitrates usually per-
colate into soils at a greater rate during the winter
months when plant uptake of nitrogen ceases, plant
decay adds nitrogen to the soil, and groundwater recharge
rates tend to increase.  When assessing groundwater
quality data, the time of testing needs to be determined,
if it is obtainable.  Data should be collected preferably
in winter or early spring.

Areas of fractured rock overlain by a shallow soil mantle
are areas of high hazard since nitrates readily pass
through the porous fissures in such rocks as creviced
dolomite, limestone and shale.

Areas of high water table  (only a few feet below the
surface) are less hazardous to groundwater from the
nitrate point of view because  the soil is in an anaerobic
state  (deficient in oxygen) where denitrification  (nit-
rate may be converted to nitrogen gas) is promoted  if
carbonaceous material is present.

Nitrates do not quickly mix with the deeper levels  of
groundwater under conditions of laminar flow, but nor-
mally  "ride on top" of the groundwater water layer  for
many months.  In taking samples it is well to know  if the
sample was taken from the  top  of the aquifer.

With data obtained  from G-l, G-2 and G-3, the following
tasks will be carried out:

Task FR-1A.  Prepare mappings  of the agricultural  areas
of  the country to show levels  of nitrate  above  acceptable
levels  (choose several levels  greater  than 5 ppm,  greater.
than  10 ppm, greater than  20 ppm, greater than  45  ppm and
greater than 100 ppm)  for  different years of testing so
as  to  indicate visually the increased  level of  nitrate
pollution where  it  exists.

Task FR-1B.  Correlate fertilizer application levels
versus crop  and  tillage practices, climatic conditions
and aquifer  flow rate.  This data will allow for
                     71

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     estimation of nitrate concentration increases in the
     groundwater through the increase of fertilizer appli-
     cation rates.  Other factors such as a change in the time
     of application, or the use of less soluble forms of
     nitrogen—such as urea—can then be studied as to their
     effect on nitrate leaching into groundwater.

     Task FR-1C.  The effort to study groundwater recharge
     must include some estimate as to the degree of recharge
     from local streams and ponds which are either high or low
     in nitrate.

     Surface streams tend to recharge the aquifers (and the
     aquifers recharge the streams).  Often, during the late
     summer, the aquifer recharges the stream more than the
     stream recharges the aquifer.  Nitrates from the top of
     the aquifer pass to the stream.  In the winter the aqui-
     fer is recharged by the stream carrying nitrates and
     other soluble substances into the aquifer.

     A study of this balance will help to indicate the source
     of intrusion of toxic substances into the groundwater.

2.   Task FR-2

     Objective;  To determine how farmers can control nitrate
     percolation into groundwater in those areas where ground-
     water nitrate problems have been traced to fertilizer
     applications.

     Scope;  In each agricultural region there are some farms
     that are operated on a scientific and cost effective
     basis.  Some of these farms are operated probably in
     areas experiencing groundwater nitrate toxification
     problems.  It is in these areas, where fertilizer appli-
     cation is suspected of being the primary contributor to
     this groundwater problem, that farms should be selected
     for study.

     There should be strong similarity between each selected
     farm and the "control" farms in the area in topography
     and the crops grown.  A number of farms should be selec-
     ted, with preferably two or three in each area studied.
     A selected pair of farms in one area may be as much as 20
     to 50 miles apart.

     Approach;  With data obtained from G-4, the tasks defined
     below will be pursued.  In the event that this approach

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is successful, there will be a strong indication that an
appropriate farm management training program would be bene-
ficial.  Also required will be effective research to determine
the capacity of crops to take up nitrates (and other nut-
rients) from fertilizers and soils.   Fertilizer applications
could then be made in optimum amounts and at judicious times
so as to minimize the leaching and runoff potential.

Task FR-2A.  The first order of business is to set criteria
and then to select and contact the farms to be used in the
study.  State or federal agricultural farms and previously
studied farms can be included if they meet the criteria listed
in the "Scope" above, but private operations will generally be
chosen. Negotiations will determine the degree of cooperation
(and the possible fee for the use of the farmer's time and
facilities) which is required.  It may be possible to in-
corporate additional funding into the study from interested
state agricultural agencies and extension services, and Water
Resources Research Centers of the State, USDA Agricultural
Research Service, USGS, soil conservation service, and land
grant college agricultural programs.  In some instances the
use of equipment and personnel from these sources may sub-
stitute for cash input to the study. For example, the state
may provide the testing of water samples free.

Task FR-2B.  A file of the farm characteristics will be made,
consisting of:  (a) a topographical map of the farm which will
also show locations of fences, buildings, wells, septic tanks,
etc.  (b) the history of the farm extending back at least 5
years, preferably 10 years or more, including all pertinent
data that will help in determining what factors contributed to
the local groundwater quality.  These data include, but are
not limited to the following:

               DATA OUTLINE

     o    Cropping patterns and amounts planted

     o    Yields

     o    Fertilizer applications and types  (include manner of
          application)

     o    Pesticide usage
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o    Tillage practices

o    Building additions and other physical changes to
     farm such as pond construction or creek dams, etc.
     (include timing information)

o    Livestock history

o    Climatic factors affecting crop

o    History of soils tests

o    History of any drilling of wells (test, drinking,
     irrigation)

o    Any practices which would affect groundwater (dump
     area for farm wastes, fertilizer and pesticide
     containers, etc.)

o    Septic tank and outhouse locations and periods of
     use (installed or stopped usage)

o    Other pertinent data such as water table levels,
     years when well was dry or low, etc.

(c) test the present farm wells for nitrate levels and
drill test wells at judicious locations about the pro-
perty to obtain edaphic, geological, and hydrological
characteristics of the farm.  Lysimeters should be placed
where appropriate.

Nutrient and microbiotic matter in the soil, soil mois-
ture, hydrologic conductivity, water quality in each of
the wells placed on the property, etc. shall be recorded
at least monthly.  Precipitation, water runoff, tem-
perature and humidity levels can be recorded automati-
cally.  The water runoff may be difficult to obtain due
to topographical characteristics and may have to go
unknown on some farms.

Task FR-2C.  Record the farm activities that take place
during the year of study, including but not limited to
the following:

o    Time of all activities

o    Record of pertinent weather conditions

o    Amounts of pertinent materials used

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          o    Tillage of various fields (plowing,  disking, etc.)

          o    Planting of seeds

          o    Fertilizer applications

          o    Irrigation water used

          o    Changes in livestock patterns

          o    Soils analyses

          o    Crop yields

          o    Pesticide applications

          o    Cutting of hay, alfalfa, etc.

          o    Changes in topographical features (e.g., new pond,
               or an old pond drained or serious erosion of an
               area)

          o    Dumping on spillage of fertilizers and pesticides on
               the farm property

          o    Dumping of wastes on the farm property

          o    Any other significant operations

          Task FR-2D.  Digest the data recorded and investigate for
          correlations between farming activities and the data
          developed on groundwater quality  (nitrates and pesticide
          residues).
B.   Feedlots

     1.   Task FE-1
          Objective;  To establish a method of standardizing
          animal waste analysis and research reporting.

          Scope;  Standardization will allow for a clear statement
          of any measurements or analysis techniques that may be
          required in future feedlot regulations as they apply to
          protecting groundwater from contamination (and as they
          apply also to runoff contamination). In order to compare
          research results and establish application rates there
          must be standardized data reporting.
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     Approach:   Data on location of research by climate and
     soil characteristics will be made.   The depth of im-
     pervious layers, water tables, and  other pertinent infor-
     mation will be reported.   This is necessary in that
     future regulations may require analyses of the quality
     and quantity of minerals  percolating through the soil as
     a result of feedlot operations.

     This approach can best be pursued by forming a team of
     experts in the field of animal wastes analysis and re-
     search.  Using data provided from Task G-l, the team will
     carry out the following:

     Task FE-1A.  Review the work previously accomplished in
     the areas of animal wastes analysis and research. Con-
     sideration must be given  to the various conditions under
     which data must be collected and the purposes for which
     it is recorded.  It is recommended  that analyses be
     expressed on a dry weight basis, except possibly for
     liquids of low solids content (approximately 1% or lo-
     wer).

     There must be a procedure established whereby data taken
     in various locations and  under extremely different cli-
     matological, edaphic, geological, and hydrological con-
     ditions can be related.  The important point of the work
     is that the method of analysis and  reporting be stan-
     dardized so that regulations can be written and enforced
     in a meaningful way.

2.   Task FE-2.

     Objective;  To assess the success of the various methods
     to control feedlot runoff and manures, particularly in
     relation to groundwater contamination. A secondary ob-
     jective is to develop a set of criteria for required
     sizes for waste storage facilities  and for maximum feed-
     lot sizes and animal densities for  specified control
     techniques used at sites in various regions of the nation.

     Scope;  During the past five years  or so techniques for
     collecting and holding feedlot runoff and manures have
     been adopted at many feedlot locations.  The effective-
     ness of these techniques must be assessed. This project
     cannot be entirely segregated from efforts to prevent
     runoff of effluents into streams and ponds which also
     recharge groundwater.

     Approach:  Investigate those feedlots which have been

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instrumented to determine the level of nitrate pene-
tration into underlying soils, and ultimately into ground-
water.  Simultaneously select additional feedlots to be
instrumented, which do not duplicate the above situat-
ions, which use alternative collection and storage tech-
niques.  This selection is to be made to represent varied
feedlot design, size, manure types, soil and climatic
conditions, geology, and hydrology.  Beef and dairy
cattle, hog, and poultry feed operations will be con-
sidered, with cattle operations receiving major emphasis.

This approach will be best accomplished by performing the
following tasks:

Task FE-2A.  Review available studies on projects which
have analyzed certain feedlot designs for collecting and
holding effluents and solids from feedlots.  It is noted
that many studies have been concerned primarily with
preventing runoff into streams and ponds.  Measurements
of nitrate levels in nearby streams are usually avail-
able.  Many studies have identified the percolation of
nitrates into the soil at points within the feedlot and
about  the perimeter. The most significant data are those
from measurements made during the winter and spring
seasons when nitrate concentrations usually appear higher.

The review should be especially concerned with areas that
include soils with  shallow groundwater  (15-50 feet)
depth.  Here nitrate concentrations in soils are im-
portant because leaching into groundwater is potentially
high.

In humid zones  the  concentration of waste salts should be
recorded and the degree of leaching determined. Where
records exist on the quality  of groundwater in the di-
rection of flow away from the feedlot the dispersion
pattern and amount  of dilution should be calculated.

Task  FE-2B.  In areas where feedlot operations are lo-
cated on permeable  soils overlying shallow aquifers, the
groundwater contamination levels need to be investigated
more  extensively.   The feedlots to be tested  for ground-
water contamination are to be those in  regions repre-
senting soil and manure types, geological, hydrological,
and  climatological  conditions not  covered by  existing
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studies as identified in Task FI5-2A.  Where feasible,
when existing studies have incomplete data, efforts to
test for the additional necessary data should be made at
these sites.

Tests should be conducted so as to obtain data which
coincides with the standardization procedures being
developed in Task FE-1.  Since both tasks FE-1 and FE-2
will be in operation simultaneously, effective coope-
ration will be needed between the two Task groups.

The testing shall be performed around the feedlot pe-
rimeter and at locations where the groundwater flows down
stream of the feedlot.  Existing wells should be utilized
when feasible, but test wells should be installed as
appropriate.  Testing should be done at several intervals
during the year to observe seasonal variations.

Test wells should be drilled to a depth which will draw
water samples from the upper levels of the aquifer.  It
is in this region that contaminants concentrate because
of the minimal vertical mixing which occurs under con-
ditions of laminar flow.  Profiles of nitrate and salt
concentrations in the soil should be obtained.  Soil
moisture, bio-oxygen demand (BOD), hydrological con-
ductivity, and other parameters should be measured as
required.  In areas where the groundwater has not been
contaminated, these data are invaluable in building a
history for the feedlot region and feedlot design.

Testing of the soils and groundwater should be coor-
dinated with testing programs presently being conducted
by the EPA's R. S. Kerr Laboratories (Ada, Oklahoma), Lhe
U.S. Department of Agriculture, and the U.S. Geological
Survey.  Some of these programs involve in-house offoris
and others are in connection with land grant schools and
state water resource research programs.

Task FE-2C.  The task force will continually synthesize
data and project the outlook for the future with respect
to feedlot designs, manure types, edaphic, geological and
hydrological conditions.  This perspective will provide
the context within which to develop the understanding
required for the design of sound regulations for ground-
water protection.
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3.   Task FE-3

     Objective;  To determine the degree of. groundwater tox L-
     fication resulting from recharge from animal waste ap-
     plications which are occasioned by feedlot operation.

     Scope;  It is recognized that there are many means of
     disposing of animal wastes, including spreading, treat-
     ing, refeeding, synthesizing, burning and so forth.  This
     task is concerned with the discharge of wastes on lands
     after various levels of treatment in holding and treating
     ponds.  This study is most concerned with the effects on
     groundwater toxification as a function of application
     rates, edaphic characteristics, climate, geology, hy-
     drology and time of application.

     Approach;  The following tasks will be carried out:

     Task FE-3A.  A survey of areas where the application of
     animal wastes is affecting permeable soils with shallow
     groundwater (15-50 feet) will probably show that these
     conditions offer higher potential of groundwater con-
     tamination than areas that are arid. A survey of the
     nitrate levels in groundwater in these regions is re-
     quired, using files from local well testing data.  This
     data will often mesh with the data collected in Task FE-2
     and there should be a close working relation between the
     two task groups.

     Task FE-3B.  Methods of application of animal wastes, as
     well as composition of the wastes, the amount and time of
     application, crop cover, climate, edaphic conditions and
     hydrology will be surveyed to determine which methods are
     applicable, and which are not, in identified regions and
     seasons.

     In Illinois, for example, nearly all recharge to ground-
     water occurs between the first of November and the end of
     April, during periods when evapotranspiration losses are
     minimal, soil moisture, deficiencies have been satisfied,
     and during periods when the ground is unfrozen.  It would
     probably be inappropriate to apply animal wastes during
     this period, unless mitigating factors allow for winter
     applications.

     Plant capacities for nitrogen uptake, and the optimum
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          times and rates of application, should be «ssesoed for
          the edaphlc conditions existing at various feedlot areas.
          Much of this data will have to be gathered from the land
          grant colleges, state agricultural research services,
          extension services, and the USDA's Agricultural Research
          Service (Dr. Stanford, USDA, Beltsville).  Minimal data
          is now available in this area.

          These factors should be identified for all areas where
          waste spreading is conducive to groundwater contami-
          nation.

          Task FE-3C.  Use the findings of this study to formulate
          guidelines or rules for upper limits on manure spreading
          in feedlot regions under specified conditions.

C.    Septic Systems and Groundwater

     1.    Task S-l

          Objective;  To determine the extent of groundwater con-
          tamination that exists on farms as a result of septic
          tank use.

          Scope;  The investigation will be limited to farms and
          will be further limited to areas representative of spe-
          cified soil conditions, geology, depth of water table,
          climate (precipitation available to dilute the waste
          water) and tank design.

          Approach:  With data obtained from Task G-l, the fol-
          lowing activities will be pursued:

          Task S-1A.  Since the density of septic tanks in farm
          areas is usually low (less than 10 units per square mile)
          the pollution potential for serious regional groundwater
          contamination probably does not exist, but local problems
          do occur.  A set of areas around the country will be
          selected for which well test records are available.  The
          areas are to be defined and segregated by soil types and
          geology.  In cases where well contaminations occur at a
          statistically significant level, investigations will be
          extended to determine the pollution source.  When septic
          sources are suspected, a study of well construction will
          be made and the corresponding septic tank history re-
          viewed.  Poor design of either the well casing or
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               positioning  may  be more  at  fault  than  the  septic  tank.
               Conversely,  the  septic design  and construction may  be
               inadequate.   A determination of  the  facets of the problem
               will thus be made.   Areas without high water  tables will
               not be included, but areas  with  fractured  porous  rock
               below a thin soil cover  should be investigated, even with
               only moderately  high water  tables.

               It is suggested  that this study  of farm  septic  tank
               pollution be made as a subset  of a national study by the
               EPA Office of Air and Waste Management in  their Solid
               Waste Management Program and that coordination be ar-
               ranged with the  R.  S. Kerr  Experimental  Research  Labo-
               ratory (Ada, Oklahoma),  where  a  long term  septic  tank
               study is already underway.

               It is anticipated from preliminary reviews that farm
               septic systems are an insignificant source of groundwater
               pollution, except on a local basis,  in relation to  the
               other sources of potential  groundwater pollution  from
               agriculture practices.   Septic systems are too  sparsely
               situated in a farm setting  to  be a major source of  nit-
               rate contamination of groundwater.

               The only farming areas where a potential for widespread
               groundwater contamination may  exist is where a  farm or
               ranch supplies a concentrated  area of housing for ranch
               and farm hands,  and septic  systems process the  human
               wastes.  This also applies  to  areas where  migrant worker
               camps service substantial numbers of people in  concent-
               rated pockets of farmland.
IV.   PESTICIDES

     A.    Task P-l
          Objective;  To determine the potential severity of toxifica-
          tion of groundwater that is suited to use for public drinking
          water supplies based on the history of past applications and
          the projected use of pesticides in the near future.

          Scope:  Since groundwater contamination by pesticides and
          herbicides has been reported in only a limited number of
          instances it will be necessary that the records of Water
          Resource Research Centers in each state be reviewed. .Only
          those states and areas with intensive farming on permeable
          soil  (sandy soil or thin permeable soil mantle over layered
                               81

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fractured rock, e.g., limestone,) with high water table
and slow moving groundwater, need to be considered. Also,
only those areas in which persistent varieties of pesti-
cides are used would require such study.

A minimum level of CH (chlorinated hydrocarbon - a per-
sistent class of pesticides) pesticide concentration in
groundwater would be set for the investigation. Only in
areas where the minimum CH levels are surpassed will
records of lower levels be investigated; this is to
identify trend patterns.

Approach;  With data obtained from Task G-l, the fol-
lowing will be carried out:

Task P-1A.  The task force formed to investigate this
problem will review the records of CH usage in agri-
culture.  These data have been published by and in the
files of the USDA, Agricultural Experimental Stations and
Agricultural Extension Services.  Only those data need to
be researched which lie within areas of intensive farm-
ing, very permeable soils (sand soils), high water table,
and slow moving groundwater.  Also, areas where the soil
mantle is thin and is underlain by a fractured rock
matrix, such as limestone, shale, etc. are candidate
areas.  The soil, geological, and hydrological data is
provided by the Soil conservation Service of the USDA,
U.S. Geological Survey, and state Geological Surveys.
The areas to be investigated are those where a high water
table is actually used for drinking water supplies.

Task P-1B.  With or without a formal groundwater mode!2
the data made available from the files of the various
state agencies identified above will be used to determine
the past, present and future migrations of CH residues.
The future migrations will have to be  (a) based on recent
(last two years) application rates of  CH; (b) based on
the projected reduced rates because of present and pend-
ing regulations; and (c) based on possible increased
applications rates if warranted.

Task P-1C.  In areas where contamination of groundwater
is known to exist, arrangements will be made for ob-
taining a new and representative set of groundwater
samples using the methodology and procedures described by
the Association of Official and Analytical Chemists
(AOAC).
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V.   ECONOMIC IMPACT OF MEASURES TAKEN TO REMEDY GROUNDWATER
     CONTAMINATION

     A.   Introduction and Overview

          This section will present a possible approach for
          assessing the economic impact of the measures taken to
          remedy groundwater contamination problems.   It consists
          of a flow diagram of the complete procedure, a set of
          three objectives and a list of specific tasks necessary
          to meet the objectives.

          The economic impact portion of the plan of  work would be
          undertaken whenever a groundwater contamination problem is
          discovered and defined.  It would begin immediately after
          standards, guidelines or other remedies had been established
          to guarantee the future purity or safety of the groundwater;
          the benefits* of these remedies are expected to exceed the
          costs of enacting them.  The economic impact analysis would
          determine the costs of the abatement more precisely and would
          allow a second posteriori assessment of the benefit assump-
          tion.

          The economic impact analysis will concentrateon the primary
          cost impacts and on the significant secondary impacts** as-
          sociated with the abatement of groundwater  contamination.
          Primary impacts are changes in the output,  costs or returns
          of firms or individuals whose operations would be directly
          affected by the standards, guidelines or remedies.  Secondary
          impacts are the changes in prices, costs or quantities of
          goods occurring in the support industries,  competing indus-
          tries or at the retail level.  An example of a support in-
          dustry is the fertilizer industry.  An example of a competing
          industry is the grassfed beef industry which would probably
          feel the impact of any feedlot regulations.  Of course, we
          are all affected by higher retail prices and by shortages.

*These benefits are primarily increases in the safety and health of
current and future generations of human beings, of other animals,
and of plants.

**It should be noted that not all secondary impacts are costs.  An
increase in the cost to one firm or an industry may benefit a competing
firm or industry.
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The procedure to be used in the economic impact analysis can
be structured according to three main objectives.  These are:
(a) to choose the best set of possible alternative remedies to
groundwater problems, (b) to determine the primary impacts of
these alternative remedies on a firm, industry and regional
basis, and (c) to identify and assess the significant secon-
dary impacts of the most promising remedies.  Inferior re-
medies will be discarded at the completion of each phase of
the analysis.  This will keep the procedure efficient.  On the
other hand, the effort made to explore alternative methods of
abatement under the first objective will help insure that the
most rational remedies are subjected to the impact analysis.

The three objectives are represented in the flow chart of the
procedure (Figure 2-V-l) as three columns.  In the lefthand
column are the tasks to be performed in choosing the best
abatement methods.  As can be noted from the diagram, either a
task-force approach or a Delphi technique can be used to
complete this objective.  In the middle column, the tasks
necessary to assess the primary impacts are shown. Firm-level
output and cost impacts would be determined while meeting the
initial objective; hence, the tasks needed to complete the
second objective are mostly concerned with aggregation to the
industry and regional levels.  The right-hand column and the
third objective are concerned with delineating the major
secondary impacts.  Tasks required to fulfill this final
objective are identification of impacts important enough to be
analyzed; choice of analytical technique to use in the anal-
ysis; and performance of the analysis itself.

Two other aspects of the flow-charted procedure should be
noted.  An option to bypass Objective 1 is included to account
for a situation where the standard, guideline or remedy is
already known and/or specified by law.  This option is not
under any of the three objectives.  Also noteworthy is the
branch in the left-hand column which indicates that if a
byproduct can be found from an abatement remedy which will pay
for the remedy, then no further study of impacts is needed.
An example of the first option might be a pesticide ground-
water pollutant for which there is a substitute pesticide.
Objective 1 can be bypassed if there is confidence that the
one pesticide will be substituted for the other.  An example
of the second option would be a manure byproduct that makes it
feasible to capture the liquid and solid wastes before they
penetrate the soil surface.
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      DBJECTIV!

          1
 Determine Remedies
           Primary Impacts
                               Secondary Impacts
Input:  Description of Contamination,
Acceptable Standards  & Affected Firms
   Choose  Remedies
   or Method of
 Evaluating Remedies
   Choose  Experts
 (Delphi Technique)
        or
   Form Task Force
               Define
          Current Production
               Regions
Remedy
  is
 Known
     Survey  for
    or  Calculate
    Technical  and
 Economic  Parameters
     Determine
Number, Type & Size
        of
  Affected Firms
I       Choose       I
I    Best Remedies   t
I                    I
L	,	1
              Use Firm
            Parameters to
          Calculate Primary
               Impacts
                                   Delineate
                                Major Secondary
                                    Impacts
      Select
Economic Technique
     to Assess
 Secondary Impacts
                                    Compute
                               Secondary Impacts
                                Using Selected
                                   Technique
                                                                     1
        I       Exit if
        I   Primary Impacts
        I     Negligible
        L	
                                   Summarize
                                Impacts & Exit
I       Exit if
I Remedy Covers Cost
                   J
            Figure 2-V-l  Flow Diagram of Economic Impact Analysis

                                       85

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B.   Task E-l:  Choose Alternative Remedies

     Objective;  The goal here is to determine the most technically
     and economically feasible ways of abating groundwater con-
     tamination.  In many cases, the most feasible abatement al-
     ternative may be well known and/or well documented in the
     literature.  For example, it may be well known that one pes-
     ticide will readily substitute for another and that this
     substitution will relieve the need for major changes in
     current agricultural production practices.  Objective 1 would
     be bypassed in this case.  A case in which Objective 1 would
     not be bypassed might be a feedlot waste disposal problem
     where the remedies could range from building an effluent and
     solid waste holding system to manufacturing a byproduct such
     as composted manure or methane gas.  In such a case, feasible
     alternatives have to be defined and their technical and econo-
     mic parameters determined before the remedies most likely to
     be used can be chosen.

     Scope;  Limited to those specific contamination problems where
     several attractive abatement alternatives exist and where
     choice of the most feasible remedy is not easily made.

     Approach;  Either a Delphi procedure or a Task Force approach
     will be used.  The Delphi approach will be preferred for the
     easier choice problems.  The more complicated Task Force
     approach would be used if the choice problem is difficult.

     Task E-1A.  Choose analytical method to be used in determining
     most feasible contamination remedies.  To do this, one would
     (a) assemble information about scope, seriousness and attri-
     butes of groundwater contamination problem (from earlier
     phases in project), (b) gather what easilyobtainable infor-
     mation about possible abatement procedures exists, and  (c) in
     conference with EPA representatives, choose either the Delphi
     technique, the Task Force approach or the most likely remedy-
     (ies).  If a remedy, or a set of remedies, is chosen during
     completion of this task, the other tasks under Objective 1
     would be omitted.

     Task E-1B.  Choose experts to be polled in Delphi technique
     or choose members of task force.  Experts for the Delphi
     procedure would come from both inside and outside government
     and would be knowledgeable about both the technical and the
     business aspects of the agricultural firms contributing to the
     groundwater contamination.  The group should include some
     representatives of the firms which would be affected by the
     abatement practices.  If a task force is formed it should
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     include  Agricultural  Scientists  (who would know about plant
     varieties,  row  spacings,  cultivation practices, etc.)> Agri-
     cultural and/or Civil Engineers  (who would know equipment  and
     processes),  and Agricultural  Economists  (who would know mar-
     kets  and comparative  costing  techniques). Such a  task force
     could use a systems approach  in  studying  the alternative
     abatement possibilities.   The credibility of this approach is
     attested to by  such successes as the development  of mechanical
     harvesting for  tomatoes.

     Task  E-1C.   Perform analyses  needed to make choice of abate-
     ment  alternatives and calculate  cost and  returns  of each
     alternative remedy.   These analyses need  to generate two kinds
     of information:  technical parameters and economic parameters.
     In the final rounds of the Delphi procedure, if it were used,
     experts  would be polled about such items  as fertilizer appli-
     cation rates, recommended varieties, sizes of holding ponds,
     equipment needed for  methane  gas production, costs of appli-
     cation,  equipment, etc. and prices of composted manure, etc.
     These questions would be formulated for  only a few of the  most
     promising remedies and only near the completion of the Delphi
     procedure;  otherwise, the response rate  of the experts will be
     inadequate.   If a task force  approach is  used, the member  of
     the force who has the relevant expertise  will take final
     responsibility  for providing  each relevant parameter.  Since
     cost  and price  parameters are included,  one output of this
     task will be the direct impacts  of the pollution  abatement on
     the affected firms.   If this  task is not  performed,  the direct
     economic impacts of  the known remedy would be calculated  as
     part  of  Task E-2C.

     Final Note;  A task  Force analysis might turn up  a byproduct
     process which will abate the  groundwater  pollution and pay for
     itself while doing so.  Objectives 2  and 3 would  be  omitted  in
     this  case as additional cost  impacts would be well outweighed
     by the benefits accruing from the pollution  abatement.

C.   Task E-2:  Determine Primary  Industry  Effects

     Objective:  Cost and/or output impacts  on the  industries
     containing the polluting firms are to  be determined  during the.
     completion of this objective.  Also,  if  the  cost  impacts
     directly associated  with polluting firms were  not calculated
     under Objective 1, they will  be determined  here.   Industry
     impacts are of  critical importance in order  to  assess  the
     national and international trade effects of  the  abatement
     remedies.  If these are negligible, costs of  abatement  will
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be borne primarily by the polluters.  If they are significant,
abatement will also include social costs.  Since these costs
may vary by region, a regional stratification will be made.
If primary impacts at the industry level are negligible,
Objective 3 can be omitted.

Scope;  Attention will be focused only on U.S. agricultural
production industries directly affected by corrective action.
The impacts of remedial action upon supportive and competitive
industries or on final consumers will be determined in Objec-
tive 3.

Approach;  The impact of corrective action will be determined
via collection and revision of existing USDA and Bureau of the
Census data.

Task E-2A.  Define Current Production Regions.  Efforts to
determine the regional distribution of production should be
closely coordinated with executors of the technical and engi-
neering phases of the total analysis.  It will be necessary to
arrive jointly at relevant regional definitions. Soil types,
and location of major market areas and supportive industries
should be considered.  Regional delineation is of critical
importance because the imposition of corrective measures could
alter significantly the nature of competition that exists
between major production areas.

Task E-2B.  Determine number and size distribution of firms
affected in each region.  It is possible that remedial action
will affect only small firms in one region.  If the region is
characterized by a wide range of firm sizes, the effects of
corrective action in all probability will be small.  However,
if the instituted action affects a large firm which accounts
for a large share of regional and national output, the econo-
mic impact could be rather significant.  Therefore, to arrive
at a realistic assessment of the primary effects it will be
necessary to consult USDA and Bureau of the Census data.
These data and associated studies will be used to derive size
distributions of firms by region.

Task E-2C.  Use firm parameters to calculate total impact on
industry by region.  Given the isolation of areas where cor-
rective action is necessary (output technical and engineering
phase) and firm parameters developed under Objective 1 of the
economic impact analysis, the total impact on the industry
will be calculated by region.  Changes in firm cost structure
reported under Objective 1 will be translated into industry
                    88

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     and regional price and quantity changes.   If the cost impacts
     on the affected firms have not been calculated previously,
     they will be computed as part of this task.   Partial budgeting
     procedures will be used to carry out this computation.

D.   Task E-3.  Determine Secondary Effects

     Objective;  The purpose of this objective is the quantifica-
     tion of the effects remedial action has on supportive and
     competitive industries.  Demand for outputs and/or services
     rendered by industries serving in support roles, such as the
     feed grain industry in the case of feedlots, could be severely
     altered by the institution of corrective measures. Competing
     industries, such as the grass-fed beef industry once again in
     the case of feedlots, may find the demand for their products
     increased as a result of government intervention.  An addi-
     tional possible outgrowth of the correction of spillover
     activities is the increase in prices at the consumer level.
     The nature of the effect on consumers, as well as the pre-
     viously mentioned secondary impacts, will be derived using the
     results generated under Objectives 1 and 2.

     Scope;  The analysis will be limited only to supportive and
     comparative industries indicated to be affected by results
     derived under Objectives 1 and 2.  Consumer impacts will be
     determined only in situations where significant price changes
     are indicated.

     Approach;  Examination of results of tasks accomplished under
     Objectives 1 and 2 to determine impact areas.   Select appro-
     priate economic tools and execute the analysis.

     Task E-3A.  Delineate major impacts which should be  studied.
     Assessment of secondary impacts will require identification of
     affected supportive and competitive industries.  Findings
     under Objectives 1 and 2 will set the initial boundaries.  For
     example, evidence discovered in the execution of tasks con-
     tained in Objective 2 may indicate a decrease in the  demand
     for feed grains as a result of feedlot regulation.   Given  this
     information, the analysis can proceed to the determination of
     the feedgrains affected.  Results obtained under Objectives 1
     and 2 will be used also in the assessment of the effects
     remedial action will have upon consumers.

     Task E-3B.  Selection  of Economic Tools.  Several possible
     economic tools are available which can be used  to perform
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          an impact analysis.   Budgeting aggregation, commodity section
          models, input-output analysis, and economic base analysis are
          examples of possible techniques which could be used to deter-
          mine the impact of remedial action on supportive and competi-
          tive industries.

          The final decision as to the technique used will be based on
          output generated under Objectives 1 and 2, in consultation
          with informed industry, EPA representatives and other quali-
          fied sources.  Consumer impacts will be derived via the use of
          the price elasticity of transmission and Griliches' social
          welfare approach.

          Task E-3C.  Execution of Analysis.  Once the boundaries for
          the analysis have been established and tools selected, it will
          be necessary only to collect the relevant data and to locate
          the necessary parameters and proceed with the chosen analy-
          tical procedure.
VI.  MODELING

     A.   Task M-l
          Objective;  The objectives of modeling a particular situation
          such as the intrusion of toxic substances into groundwater
          recharge, whether from nitrates or pesticides, is to be able
          to predict on a fairly reliable basis what the future conse-
          quences will be with continued use of these substances.
          Modeling should also permit us to vary certain parameters so
          as to determine the application level at which the substance
          would no longer toxify the groundwater. It is desired that
          modeling be capable of dealing with large land areas in order
          to describe adequately the expected effect on an aquifer for
          several years in advance.

          Scope;  At present the state-of-the-art in groundwater model-
          ing does not permit the modeling of large areas.  It will be
          necessary therefore to determine the extent to which various
          existing models can be adapted to this purpose, and the degree
          of reliable prediction to be expected and the number of input
          parameters required.  The task will be to select a model or to
          adapt a set of models and suitable submodels which can fulfill
          the objective of this program. Modeling of a sophisticated
          nature is not warranted for areas showing small changes of
          nitrate in groundwater over a period of a decade or more since
          fertilizer and animal waste applications obviously do not add
          significantly to these groundwater contaminations.
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Approach;  The objectives of the program will be reached by
the accomplishment of the following tasks:

Task M-1A.  During June of 1975 the EPA awarded a contract to
the Commission on Stimulation Modeling of the Scientific
Committee on Problems of the Environment to evaluate the
existing groundwater basin management models (EPA project
control number R803713-01).  A liaison with this committee
should be established by the EPA groups concerned with model-
ing the effects of fertilizers, pesticides, feedlots, and
septic tanks on groundwater recharge.  Even though the commit-
tee's work is scheduled for completion in July 1976, the
modeling groups will receive invaluable benefit from the
collected ideas and will also be able to share their insights.

Among the above group of individuals interacting with the
Committee the EPA should assign a team of persons who-will be
responsible for developing a groundwater model.

Task M-1B.  (a) Using the findings of the Scientific Committee
on Problems of the Environment, a modeling effort for fertili-
zers can develop a non-point source model to predict the
quantity of groundwater which will be toxified by applications
of fertilizer under various assumptions.  The initial phase of
this Task will be to develop a working model which will pre-
dict the effects on groundwater from various levels of ferti-
lizer applications versus suitable parameters within a water-
shed or basin.  This will be utilized to determine the time
period in which toxification will occur  (if indeed it will).
It will also be an aid to agricultural extension services
around the country in recommending fertilizer application
rates so as to protect groundwater recharge.

Task M-1B would be designed to model a watershed or basin
using available data from well tests.  The well data will have
to span at least a decade or more and be correlated to ferti-
lizer application levels  (along with crop practices, clima-
tology, hydrology, etc.) of the affected area.  The modeling
effort will be designed to produce a simplified model which
will take into consideration the change  in fertilizer appli-
cation patterns over the years and relate them to the changes
in the nitrate levels in the groundwater (as recorded from
well test sample taken over the last decade). Once an histo-
rical pattern is determined, fertilizer  application levels
should be simulated which show how the groundwater nitrate
level can be influenced by fertilizing at versus other
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relevant factors including changes of crop or tillage prac-
tices.

The data for Task M-1B will be supplied through the efforts of
the Fertilizer Task group determining the extent of nitrate
toxification of groundwater as resulting from fertilizer
usage.  (b) Part 2 of Task M-1B is the same as Part 1, except
that it would be applied to pesticides using data supplied by
the Pesticide Task group.

Task M-1C.  In that the EPA, Athens, Georgia, laboratory is
already concerned with modeling the effects of pesticide in
sub-surface and surface run-off situations, and are funding an
approximately 20 square mile test area to calibrate the model,
it would be reasonable to extend the program by means of
additional funding to include the effects of pesticides on
underground recharge areas in addition to those of subsurface
run-off aquifers, (i.e., those aquifers which intersect a
surface water body such as a river or lake.)  Only a modest
increment in funds would be required to develop a subprogram
to handle the case in hand.

Task M-1C would be a more detailed effort that Task M-1B and
would demand more specific data to be taken and cover a less
extensive area than Task M-1C.

Task M-1D.  An effort to model point sources of nitrate in-
trusion into soils, (i.e., from feedlots, barnyards, dairy cow
milking areas, poultry houses, and septic tank operation)
should be attempted using models developed by ERDA, which
already account for various ground factors and chemical chan-
ges.  This modeling group can be the same group as described
in Modeling Task M-1B; if a different group, it should operate
in a manner similar to that of modeling Task M-1B.  The model
should include operation of the point source during the start-
up period, normal operation period, and phase-out period.  The
model should predict what limits are to be set on size, dis-
tance from the aquifer and/or wells, and the conditions of
operation of the point source, in order to preserve the quali-
ty of the underground waters.

Note on Modeling Task;  Modeling is not a problem in itself
but a tool for analysis.  The sophistication of the model
should be of the same order of magnitude as the precision of
the data which will be available as input to the model.
                    92

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                     THE IMPACT OF INTENSIVE
                    APPLICATION OF PESTICIDES
                 AND FERTILIZERS ON UNDERGROUND
                      WATER RECHARGE AREAS
                     WHICH MAY CONTRIBUTE TO
                     DRINKING WATER SUPPLIES

                            Section 3

                          Bibliography
1.   Aldrich, S.R.,  Determining Application Rates of Livestock Wastes
          to the Land, Livestock Waste Management Conference, 1973.

2.   	.   Plant Nutrients, Illinois Pollution Control
          Board, 1972.

3.   Allison, F.E.,  "Nitrogen and Soil Fertility, "U.S. Yearbook of
          Agriculture, pp. 86, 1957.

4.   Brady, N.C., The Nature and Properties of Soils, MacMillan
          Publishing Company Inc., Newark 8th Edition, 1974.

5.   Bredehoeft, J.D., Finder, G.F., Application of Transport Equations
          to Groundwater Systems, Underground Waste Management and
          Environmental Implications Proceedings of a Symposium held
          jointly by the USGS and the American Association of
          Petroleum Geologists, pp. 191, 1972.

6.   	.   "Mass Transport in Flowing Groundwater," Water
          Resources Research, Volume 9, Number 1, pp. 194, 1973.

7.   Brezonik, P.L.  and Lee, G.F., "Denitrification as a Nitrogen Wink
          in Lake Mendota, Wisconsin," Environmental Science and
          Technology,  1968.

8.   Butchbaker et al, Evaluation of Beef Cattle Feedlot Waste
          Management Alternatives, EPA, 1971.

9.   Case, A.A., The Health Effects of Nitrate in Water, Proceedings
          of the 12th Sanitary Engineering Conference, University of
          Illinois,  1970.

10.  Commoner, B., The Killing of a great Lake, World Book Year Book,
          1968.
                                93

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11.  Corey, R.B. et al, Excessive Water Fertilization, Report to  the
          Water Subcommittee of State Agencies, 1967.

12.  Crawford, N.H. and Donigian, A.S., Pesticide Transport and Runoff
          Model for Agricultural Lands, EPA, Office of Research and
          Development, 1973.

13.  Crosby, J.W. Ill, Johnstone, D.L., Drake, C.E., and Fenton,  R.L.,
          "Migration of Pollutants in a Glacial Outwash Environment,"
          Water Resources Research, Volume 4, Number 5, 1968.

14.  Davidson, J.M. et al, Use of Soil Parameters for Describing
          Pesticide Movement Through Soils, EPA, National Environmental
          Research Center, 1975.       •

15.  Doneen, L.D., Effects of Soil Salinity and Nitrates on the
          Drainage in San Joanquin Valley, California, Water Sciences
          and Engineering, paper 4002.

16.  Duguid and Reeves, Material Transport Through Porous Media:  A
          Finite-Element Galerkin Model, Oak Ridge National Laboratory,
          ERDA, 1975.

17.  EcoSystems, Incorporated, A Manual for Executing Short-Run Studies
          on the Economic Impact of the Restriction of Carbaryl or
          Other Insecticides, 1975.

18.  Eliassen, R. and Techobanoglous, G., Removal of Nitrogen and
          Phosphorous from Waste Water, Environmental Science and
          Technology, 1969.

19.  Engberg, Richard A., The Nitrate Hazard in Well Water With Special
          Reference to Holt County, Nebraska, USGS Professional Papers,
          1967.

20.  Erwin, B. and Waterworth, A., Nitrogen Cycle in Surface and
          Subsurface Waters, EPA, Office of Research and Monitoring,
          1973.

21.  Eye, J.D., Aqueous Transport of Dieldrin Residues in Soils,  J.
          Water Poll. Contr. Fed., 40(8), Pt. 2, pp. 316-331, 1968.

22.  Faye, R.E., Mathematical Model of the San Juan Valley Groundwater
          Basin, San Benito County, California, USGS, 1974.

23.  Federal Working Group on Pest Management.  Guidelines on Sampling
          and Statistical Methodologies for Ambient Pesticides Moni-
          toring, October 1974.
                              94

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24.   Frere, M.H., "Adsorption and Transport of Agricultural Chemicals
          in Watersheds," Transactions of the American Society of
          Agricultural Engineers, Volume 16, Number 3, 1973.

25.   Frere, M.H., Onstad, C.A. and Holtan, H.N., ACTMO:  An Agricultural
          Chemical Transport Model, Agricultural Research Service,
          USDA, 1975.

26.   Fuhriman and Barton, Groundwater Pollution in Arizona, California,
          Nevada and Utah, EPA, 1971.

27.   Garner and Smith, The Disposal of Cattle Feedlot Wastes by
          Pyrolysis, EPA, 1973.

28.   Green, R.E.,.Pesticide Mobility and Degradation in Soil-Waste
          Systems,  University of Hawaii, 1974.

29.   Griliches, A., "Research Costs and Social Returns:  Hybrid Corn
          and Related Innovations," Journal of Political Economics,
          66:419-431.

30.   Hargett, N.L., Fertilizer Summary Data, National Fertilizer
          Development Center, 1974.

31.   Harmeson, R.H. and Larson, T.E., Interim Report on the Presence
          of Nitrates in Illinois Surface Waters, Proc. 111.
          Fertilizer Conf., 111. Fertilizer Ind. Assoc., Champaign,
          111. pp. 33, 1969.

32.   Harshbarger, et al, Arizona Water, USGS, 1966.

33.   Hirsch, P., Overein, L. and Alexander, M., Formation of Nitrite
          and Nitrite by Actinomycetes and Fungi, J. Bacteriol.
          82:442-448.

34.   Hutchison, G.L. and Viets, F.G., Jr., "Nitrogen Enrichment of
          Surface Water by Absorption of Ammonia Volatilized from
          Cattle Feedlots," Science, Number 166, pp. 514-515,  1969.

35.   Ingols, R.S. and Navarre, A.T., "Polluted Water from the  Leaching
          of Igneous Rock," Science, Number 116, pp. 595-596,  1952.

36.   James, L., and Lee, R.E., Economics of Water Resources Planning,
          McGraw-Hill Book Company, New York, pp. 615,  1971.

37.   Karubian, J.F., Polluted Groundwater:  Estimating  the  Effects  of
          Man's Activities, EPA, National Environmental Research
          Center, Las Vegas, Nevada, 1974.
                                95

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38.  Keeley, J.W.,  and Sealf, M.R., "Aquifer Storage Determination by
          Radiotracer Techniques," Groundwater, Volume 7, Number 1, 1969.

39.  Kohl, D.H., Shearer, G.B. and Commoner, B., "Fertilizer Nitrogen:
          Contribution to Nitrate in Surface Water in a Corn Belt
          Watershed," Science, Number 174, pp. 1331-1334, 1971.

40.  Krause, H.H. and Batsh, W., "Movement in Fall-Applied Nitrogen
          in Sandy Soil," Can. J. Soil Science, Number 48, pp. 363-365,
          1968.

41.  Lagerwerff, J.V., Heavy Metal Contamination of Soils, USDA, 1966.

42.  Lehr, et al, Proceedings of the Second National Groundwater Quality
          Symposium, EPA, 1974.

43.  Lijinsky, W.,  and Epstein, S., "Nitrosamines as Environmental
          Carcinogens," Nature, 225, 21, 1970.

44.  Lorimor, J.C.  et al, "Nitrate Concentrations in Groundwater
          Beneath A Beef Cattle Feedlot," Water Resources Bulletin,
          Volume 8, Number 5, 1972.

45.  Mansfield, G.R. and Boardman, Leona, "Nitrate Deposits in the
          United States," U. S. Geological Survey Bulletin, Number 838,
          1932.

46.  Marshall, K.C. and Alexander, M., Nitrification by Aspergillus
          Flavus, J. Bacteriol, Number 83, pp. 572-578, 1962.

47.  McCoy, E., Nitrogen Cycle in Surface and Subsurface Waters, Tech.
          Compl., Rep. OWRR B-004-Wis., pp. 30-42, 1968.

48.  Mishan, E.J.,  Economics for Social Decisions;  Elements of Cost-
          Benefit Analysis, Praeger Publishers, New York, pp. 151, 1973.

49.  Murphy, L.S. and Gosch, J.W., Nitrate Accumulation in Kansas
          Groundwater, Proj. Compl. Rep. Kan. Water Resources Res. Ins.,
          Kan. State University, Manhattan, Kansas, 1970.

50.  National Academy of Sciences, Accumulation of Nitrate, pp. 106,
          1972.

51.  National Research, Council, "Agricultural Soil Maps," Highway
          Research Board, 1957.

52.  National Science Foundation, Executive Summary and Continuation
          Proposal for Study of Certain Ecological and Economic
          Consequences of the Use of Inorganic Nitrogen Fertilizer,
          1974.
                                96

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53.  Papadopulos and Winograd, Storage of Low-Level Radioactive Wastes
          in the Ground:  Hydrogeologic and Hydrochemical Factors, EPA,
          1974.

54.   Pauszek, F.H., Digest of the 1972 Catalog of Information on Water
          Data, USGS Water Resources Investigations Number 63-73, 1973.

55.   Pinder, G.F., "A Galerkin-Finite Element Simulation of Groundwater
          Contamination on Long Island, New York," Water Resources
          Research, Volume 9, Number 6, pp. 1657-1669, December 1973.

56.   Porter, L.K. and Beard, W.E., "Retention and Volatilization of
          Lindane and DDT in the Presence of Organic Colloids Isolated
          from Soils and Leonardite," Agricultural and Food Chemistry,
          Volume 16, Number 2, pp. 344, March/April, 1968.

57.   Proctor, D.E., Amounts, Composition, Characteristics and Pollutional
          Properties of Animal Wastes, Proceedings of the Pacific
          Northwest Animal Industry Waste Conference, 1964.

58.   Reeves and Duguid, Water Movement Through Saturated-Unsaturated
          Porous Media:  A Finite-Element Galerkin Model, AEG, Oak
          Ridge National Laboratory, 1975.

59.   Robbins, J.W.D. and Kriz, G.J., "Groundwater Pollution By
          Agriculture," Groundwater Pollution, 1973.

60.   Robertson, J.B., Digital Modeling of Radioactive and Chemical
          Waste Transport in the Snake River Plain Aquifer at the
          National Reactor Testing Station, Idaho, USGS, 1974.

61.   Robson, S.G., Feasibility of Digital Water-Quality Modeling
          Illustrated By Application at Barstow, California, USGS, 1973.

62.   Scalf, M.R. et al, Fate of DDT and Nitrate in Groundwater, Robert
          S. Kerr Water Research Center, ADA, Oklahoma, 1968.

63.   Schmitz and Seckler, "Mechanized Agriculture and Social Welfare:
          The Case of the Tomato Harvester," Journal of Agricultural
          Economics. Volume 52, Number 4, pp. 569-577, 1970.

64.   Scientific Committee on Problems of the Environment, Evaluation
          of Existing Groundwater Basin Management Models, to be
          published in 1976.

65.   Shuyler, L., National Animal Feedlot Wastes Research Program,
          EPA, 1973.
                                97

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66.  Smith, G.E., Nitrate Problems in Plants and Water Supplies in
          Missouri, Mo. Agr. Exp. Sta., Columbia, Mo., 1965.

67.  Soils Science Society of America, Symposium on Pesticides and
          Their Effects on Soils and Water, ASA Special Publication
          Number 8, 1966.

68.  Spencer, W.F., "Distribution of Pesticides Between Soil, Water
          and Air," Pesticides in the Soil;  Ecology, Degradation
          and Movement, 1970.

69.  Stanford, George, Development and Utilization of Improved
          Methods for Predicting Nitrogen Fertilizer Needs in
          Agriculture:  A Preliminary RANN-NSF Proposal, 1975.

70.  Stanford, George, Epstein, Eliot, "Nitrogen Mineralization-Water
          Relations in Soils," Soil Science Society of America
          Proceedings, Volume 38, Number 1, pp. 103, 1974.

71.  Starkey, R.L., Interrelationships Between Microorganisms and Plant
          Roots in the Rhizosphere, Bacteriol. Rev., 22:154-176, 1958.

72.  Stewart, B.A. et al, Distribution of Nitrates and Other Water
          Pollutants Under Fields and Corrals in the Moddle South
          Platte Valley of Colorado, U.S. Department of Agriculture,
          1967.

73.  Taylor, C.R., Swanson, E.R., Economic Impact of Imposing Per
          Acre Restrictions on Use of Nitrogen Fertilizer in
          Illinois, Illinois Agricultural Economics, 1974.

74.  Thomas, H.E., "Groundwater Regions of the U.S. - The Storage
          Facilities," The Physical and Economic Foundation of
          Natural Resources, Volume 3, 1952.

75.  Thomson, T.L., The Occurrence of Nitrifying Microorganisms in
          Aquatic Environment, University of Wisconsin, 1966.

76.  Tiebout, C.M., The Community Economic Base Study, Committee for
          Economic Development, 1962.

77.  U. S. Department of Agriculture.  Cattle Feeding in the U. S.,
          Economic Research Service, 1970.

78.  	.  "Commercial Fertilizers," Statistical Reporting
          Service, Bulletin Number 472, 1971.

79.  	.  Commercial Fertilizers:  Consumption in the
          U. S. FY 1974, Statistical Reporting Service, 1975.
                                98

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80.   	.   Cropping Practices:  Corn, Cotton, Soybeans
          and Wheat 1964-70, Statistical Reporting Service.

81.   Quantities of Pesticides Used by Farmers in 1966, Economic Research
          Service, Agricultural Economic Report Number 179, 1970.

82.   U. S. Department of Commerce, "A Multiregional Input-Output Model
          for the United States," Economic Development Administration,
          1970.

83.   	.   Detailed Housing Chatacteristics, Bureau of the
          Census, 53 Volumes, 1970.

84.   U. S. Department of Commerce, Groundwater Pollution, Part 2:
          Pollution from Irrigation and Fertilization, A Bibliography
          with Abstracts, National Technical Information Service, 1975.

85.   U. S. Environmental Protection Agency, Abbreviated List of Publications
          and Guideline Documents Dealing with Monitoring Quality
          Insurance, Office of Monitoring Systems, 1974.

86.   	.   Groundwater Contamination in the Northeast States,
          Office of Research and Development, June 1974.

87.   	.   The Movement and Impact of Pesticides Used for
          Vector Control on the Aquatic Environment in the Northeastern
          U. S., Office of Water Programs, 1972.

88.   	.   The National Groundwater Quality Symposium.

89.   	.  On Site Domestic Waste Disposal, Office of Air
          and Waste Management, June 1975.

90.   U.S. Geological Survey, Catalog of Information On Water Data,
          Volumes 1-19, Office of Water Data Coordination, 1973.

91.   	.  Distribution of Principal Kinds of  Soils:  Orders,
          Suborders, and Great Groups  (map), 1967.

92.   	.  Geology  (map),  1966.

93.   U. S. Public Health Service, U. S. Public Health Service Chemical  "
          Standards of Drinking Water, 1962.

94.   U. S. Water Resources Council, Essentials of Groundwater Hydrology
          Pertinent to Water Resource  Planning, Hydrology  Committee,
          1973.
                                99

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95.  VanderLeeden, F., Cerrillo, L.A., and Miller, D.W.^ Groundwater
          Pollution Problems in the Northwestern United States, EPA,
          Office of Research and Development, 1974.

96.  Versar Inc., "Identification of Organic Compounds in Effluents
          from Industrial Sources," April 1975, for Office of Toxic
          Substances, EPA.

97.  Viets, F.G. and Hageman, R.H., "Factors Affecting the Accumulation
          of Nitrate in Soil, Water and Plants," Agricultural Handbook,.
          Number 413, 1971.

98.  Wadleigh, C.H., Wastes in Relation to Agriculture and Forestry,
          Agricultural Research Service, 1968.

99.  Weber, J.B. et al, "Pesticides:  How They Move and React in the
          Soil," Crops Soils, Volume 25, Number 1, pp. 14-17, 1972.

100. Private communication with Hend Gorchev, P.E., Ph.D. EPA Office
          of Research and Development, Washington, D.C.

101. Private communication with Dr. Yaron Sternberg, Engineering,
          Univ. of Maryland.

102. Private communication with Dr. Charles Helling, USDA, Agricultural
          Research Service, Beltsville, Md.

103. Private communication, Dr. H. P. Nicholson, EPA Southeast
          Environmental Research Laboratory, Athens, Georgia.
                               100

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
 1. REPORT NO.
  EPA 560/3-75-006
                             2.
                                                           3. RECIPIENT'S ACCESSION-NO.
 4. TITLE AND SUBTITLE
 The Impact of  Intensive Application of Pesticides  and
 Fertilizers on Underground Water Recharge Areas Which
 May Contribute to  Drinking Water Supplies	
                  6. REPORT DATE
                    December 11.  1975
                  6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
    David Garrett,  P.E.,  Francis P. Maxey,
    Herbert Katz
                                                           8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
    Special Projects Branch
    Office of  Toxic Substances (WH-557)
    Washington,  D.C.  20460
                                                           10. PROGRAM ELEMENT NO.
                          N/A  .
                   11. CONTRACT/GRANT NO.
 12. SPONSORING AGENCY NAME AND ADDRESS
    U.S. Environmental Protection Agency
    Office  of  Toxic Substances
    Washington,  D.C.   20460
                                                           13. TYPE OF REPORT AND PERIOD COVERED
                   14. SPONSORING AGENCY CODE
 15. SUPPLEMENTARY NOTES
 16. ABSTRACT
 A report was  submitted on an assessment  of  the impact of intensive application of
 pesticides  and fertilizers on underground water recharge areas which may  contribute to
 drinking water supplies and also a plan  for developing additional information required
 to define  the nature and extent of the impact of agricultural practices on groundwater
 supplies for  public water systems, as required by the Safe Drinking Water Act (PL-93-
 523).

 Both  the assessment and the plan were subsumed under the four headings of nitrates,
 pesticides, economic impacts, and modeling  and simulation.

 Sources of  groundwater pollutants were considered with a view towards determining thei
 relative contribution to the overall problem.  Special emphasis was placed on feedlot
 operation,  a source of significant concern.  Fertilizers, pesticides, and septic tanks
 were  also  examined, along with a detail  examination of the nitrogen cycle.  Economic
 impact of  changes in a&ronswie jp-raetices y&?p t.akfiji intp ac.c,ountj, and  suggestions
 were  nade  concenuiisg; the
 7.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
 Pesticides  in Groundwater
 Fertilizers in Groundwater
 Groundwater
 Pesticides  in Drinking Water
 Fertilizers in Drinking Water
 Groundwater as Drinking Water Supply
Nitrates in Groundwater     Groundwater
Nitrates in Drinking Water    Vulnerability
Phosphates in  Drinking Water  Modeling Ground-
Phosphates in  Groundwater       water
Feedlot Pollution  of Ground-    Contamination
  water
Septic Tank Pollution of Groundwater
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