EPA/600/R-94/051
                                                May  1994
POTENTIAL GROUNDWATER CONTAMINATION FROM INTENTIONAL AND
          NONINTENTIONAL STORMWATER INFILTRATION
                              by
              Robert Pitt, Shirley Clark, and Keith Parmer
           Department of Civil and Environmental Engineering
                University of Alabama at Birmingham
                   Birmingham, Alabama 35294
               Cooperative Agreement No. CR 819573
                         Project Officer

                       Richard Field, Chief
          Storm and Combined Sewer Pollution Control Program
                Risk Reduction Engineering Laboratory
                    Edison, New Jersey 08837
           RISK REDUCTION ENGINEERING LABORATORY
            OFFICE OF RESEARCH AND DEVELOPMENT
           U.S. ENVIRONMENTAL PROTECTION AGENCY
                    CINCINNATI, OHIO 45268

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                                   TECHNICAL REPORT DATA
                            ffleae rod Juarucrioru on the rertne before completing
  REPORT NO.
                             2.
                                                          3. RE
                                                                      PB94-165354
4. TITLE AND SUBTITLE

   Potential Groundwater Contamination From  Intentional
   and Non-Intentional Stormwater Infiltration
             5. REPORT DATE
                        May 1994
             6. PERFORMING ORGANIZATION CODE

                        EPA/ORD
 7. AUTHOR(S)
   Robert Pitt, Shirley Clark, and Keith Parmer
             8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
    Department of Civil and Environmental Engineering
   University of Alabama at Birmingham
   Birmingham, AL  3529^
             10. PROGRAM ELEMENT NO.
             11. CONTRACT/GRANT NO.
              Cooperative Agreement
              CR819573
 12. SPONSORING AGENCY NAME AND ADDRESS
  U.S.  Environmental Protection Agency
  Risk  Reduction Engineering Research Laboratory
  Office of Research and Development
  Cincinnati, Ohio  ^5268
             13. TYPE OF REPORT AND PERIOD COVERED

             Pro.lect Report; 10/1/92-9/^0/9-
             14. SPONSORING AGENCY CODE

                EPA/600/14
 15. SUPPLEMENTARY NOTES

  Richard Field, Project Officer, 908-321-667^
 16. ABSTRACT
   This report is a summary of research conducted during the first year of  a three
   year  cooperative  agreement  to  identify  and  control  stormwater  toxicants,
   especially  from  adversely  impacting  groundwater.   Previous   projects   have
   identified  many organic and  heavy metal  toxicants in  stormwater and  surface
   receiving waters.  Several projects have also documented  the extensive  nature of
   receiving  water  impacts  from  stormwater  discharges  to  creeks  and  streams,
   especially  biological impacts.   Infiltration of stormwater has  received  much
   attention as a way  to reduce  these stormwater discharges to surface waters and
   to help  restore the  hydrologic balance  in  urban  areas.   The  purpose of  this
   research effort  was to review  the groundwater contamination  literature as  it
   relates to  stormwater.  Potential problem pollutants were  identified, based on
   their mobility,  their abundance  in stormwater, and their  treatability before
   discharge.  This information was used with earlier U.S. Environmental Protection
   Agency research results to identify the  likely source areas for these  potential
   problem pollutants.   Recommendations  are also made for stormwater infiltration
   guidelines in different areas  and  monitoring that should be conducted  to evaluate
   a specific  stormwater for groundwater  contamination potential.
17.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
Drainage  systems,  water
pollution control,  Ground
water  pollution,  *Storm
runoff, *Urban runoff,
Urban hydrology, Wafer
pollution  sources,  Water .
pollution  effects.'Hazardo
substances, S_qujiqe. control
c. COSATI Field/Group
 * Grounds-water;, Infiltration galleries,
  Percolation,  Hydrology, Drainage,
  *Surface  water runoff, *Runoff, Contamin-
  ants, *Storm  sewers,  "Water Quality,
  Sewage, *Water pollution, Wastewater
18. DISTRIBUTION STATEMENT
  Release to Public
                                              19. SECURITY CLASS fThaRtport)

                                              Unclassified    	
                           21. NO. OF PAGES

                           	195
                                              20. SECURITY CLASS (This ptgt>
                                               Unclassified
                                                                        22. PRICE
CPA Form 2220-1 (t-73)

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                                         NOTICE
       The information in this document had been funded wholly or in part by the United States
Environmental Protection Agency under cooperative agreement no. CR 819573 for the University of
Alabama at Birmingham. Although it has been subjected to the Agency's peer and administrative review
and has been approved for publication as an EPA document, it does not necessarily reflect the views of
the Agency and no official endorsement should be inferred. Also, the mention of trade names or
commercial products does not imply endorsement by the United States government.

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                                         FOREWORD


       Today's rapidly developing and changing technologies and industrial products and practices
frequently carry with them the increased generation of materials that, if improperly dealt with, can
threaten both public health and the environment. The U.S. Environmental Protection Agency is charged
by Congress with protecting the Nation's land, air, and water resources. Under a mandate of national
environmental laws, the Agency strives to formulate and implement actions leading to a compatible
balance between human activities and the ability of natural systems to support and nurture life. These
laws direct the EPA to perform research to define our environmental problems, measure the impacts and
search for solutions.

       The Risk Reduction Engineering Laboratory is responsible for planning, implementing, and
managing research, development, and demonstration programs to provide an authoritative, defensive
engineering basis in support of the policies, programs, and regulations of the EPA with respect to
drinking water, wastewater, pesticides, toxic substances, solid and hazardous wastes, and Superfund-
related activities. This publication is one of the products of that research and provides a vital
communication link between the researcher and user community.

       The purpose of this report is to provide guidance to stormwater planners, drainage engineers,
and local regulatory personnel concerning groundwater  contamination potential of stormwater infiltration
practices. It includes an extensive literature review of groundwater problems associated with stormwater.
Most stormwater can likely be infiltrated with minimal impacts. Removal processes in soils are likely to
reduce most infiltrated pollutants. However, some pollutants are much more likely to cause problems
than most. These must be more carefully considered in  infiltration projects. Critical pollutant source
areas need to be avoided and pretreatment before infiltration to remove particulate forms of the
pollutants should be considered.

       Future phases of this cooperative agreement are to examine pretreatment options to reduce
stormwater toxicants before discharge, and to perform an in-situ  evaluation of a stormwater infiltration
trench gallery.
                                                          E. Timothy Oppelt, Director
                                                          Risk Reduction Engineering Laboratory
                                              in

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                                          ABSTRACT


        This report is the result of research conducted during the first year of a three year cooperative
 agreement to identify and control stormwater toxicants. Many previous projects have identified many
 organic and heavy metal toxicants in stormwater and surface receiving waters. Several projects have
 also documented the extensive nature of receiving water impacts from stormwater discharges to creeks
 and streams, especially biological impacts. Infiltration of stormwater has received much attention as a
 way to reduce these stormwater discharges to surface waters and to help restore the hydrologic balance
 in urban areas. The purpose of this report was to review the groundwater contamination literature as it
 relates to stormwater and wastewater contaminants known to exist in stormwater. This information was
 used to supplement the few studies that have examined groundwater contamination problems associated
 with stormwater infiltration. Potential problem pollutants were identified, based on their mobility, their
 abundance in stormwater, and their treatability before discharge. This information was used with earlier
 EPA research results to identify the likely source areas for these potential  problem pollutants.
 Recommendations were also made for stormwater infiltration guidelines in different areas and monitoring
 that should be conducted to evaluate a specific stormwater for groundwater contamination potential.

        Other project activities during this first year included the design and installation of a special
treatment device that can be used at critical source areas to reduce groundwater contamination. Several
 inlet control devices have also been installed. These devices are being monitored during the second
 project year to evaluate their removal effectiveness for critical pollutants. The third project year will
 include the in-situ evaluation of an  existing groundwater infiltration trench gallery.

       This report was submitted in partial fulfillment of cooperative agreement no. CR 819573 under
the  sponsorship of the U.S. Environmental Protection Agency. This report  covers a period from October
 1, 1992 to September 30, 1993.
                                              IV

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                                        CONTENTS
Foreword	    iii
Abstract	     iv
Tables	    vi
Acknowledgments	   vii

       1. Summary and Conclusions  	     1
              Characteristics of Urban Runoff	    2
              Constituents of Concern	    3
              Treatment of Stormwater	    7
              Conclusions	    8
              Recommendations	     9
       2. Characteristics of Urban Runoff	   13
              Stormwater Characteristics	   13
              Combined Sewage Characteristics	    22
              Relative Contributions of Urban Runoff Flow Phases	   22
              Pollutant Contributions from Different Urban Source Areas	   30
       3. Potential Groundwater Contamination Associated with Urban Runoff	   42
              Groundwater Contamination Associated with Nutrients	   42
              Groundwater Contamination Associated with Pesticides	   48
              Groundwater Contamination Associated with Other Organic Compounds	   59
              Groundwater Contamination Associated with Pathogens	    67
              Groundwater Contamination Associated with Metals	   75
              Groundwater Contamination Associated with Salts and other Dissolved Minerals.  .   81
              Groundwater Contamination Associated with Suspended Solids	   84
              Dissolved Oxygen Groundwater Problems	   85
       4. Treatment Before Discharge of Stormwater	    86
              Solubilities and Treatment Potentials of Significant Urban Runoff Toxicants	   86

              Outfall Pretreatment Options Before Stormwater Infiltration	   94
              Local Pretreatment Options Before Source Area Stormwater Infiltration	   99

References	  102
Appendix	  116
       A. Annotated Bibliography of Groundwater Contamination	  116
              Groundwater Contamination Bibliography	  178

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                                          TABLES
 1 . Heavy metal source area observations .........................................      4
 2. Toxic organic source area observations .........................................     4
 3. Reported filterable fractions of stormwater toxicants from source areas .................     7
 4. Groundwater contamination potential for stormwater pollutants .......................      9
 5. Characteristics of stormwater runoff ............................................    14
 6. Median stormwater pollutant concentrations for all sites by land use ...................     15
 7. Pathogenic microorganisms found in urban stormwater .............................     17
 8. Summary of NURP priority pollutant analyses ....................................     20
 9. Hazardous and toxic substances found in urban runoff ..............................    21
 10. Pollutant concentrations in combined sewer overflows .............................    23
 1 1 . Selected combined sewer overflow bacteria data .................................    24
 12. Geometric mean densities of selected pathogens and indicator microorganisms in
      Baltimore stormwater and combined sewage ..................................    25
 13. Concentrations of heavy metals in combined sewer overflows .......................    26
 14. New York combined sewer overflow quality summary .............................     27
 15. Median concentrations observed at Toronto outfalls during warm weather ..............    28
 1 6. Median concentrations observed at Toronto outfalls during cold weather ...............     29
 17. Toronto cold weather snowmelt source area sheetflow quality  .......................    31
 1 8. Toronto warm weather source area sheetflow quality  .............................     33
 19. Ottawa sheetflow bacteria characteristics  ......................................    35
 20. Birmingham source area sheetflow quality ......................................    36
 21 . Groundwater nitrate contamination in the United States ............................    44
 22. Pesticides of potential concern in groundwater contamination studies .................     50
 23. Mobility class definition [[[     53
 24. Organic compound mobility for sandy loan soils ..................................    54
 25. Organic compound mobility classes for silt loan soils  .............................     56
 26. Pesticide toxicological data .................................................    60
 27. Organic compounds investigated during groundwater contamination studies ............    62
 28. Virus types [[[     68
 29. Soil characteristics for pathogen removal  ......................................     70
 30. Factors that influence viral movement in soil to groundwater .......................     72
 31 . Enteroviruses and diseases .................................................    74
 32. Metal mobility ............................................. '.'. . . ..........    77
 33. Metal removal mechanisms in soil  ...........................................     79
 34. Importance of environmental processes for the aquatic fates of various polycyclic
       aromatic hydrocarbons and phthalate esters .................................    95
 35. Importance of environmental processes for the aquatic fates of various phenols

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                                    ACKNOWLEDGMENTS


       The project was prepared with the assistance of many individuals. Two Coca Cola summer
interns, Shirita Scott and Camille Hubbard, assisted in the laboratory and helped prepare the
bibliographic information system on groundwater impacts. A number of University of Alabama at
Birmingham Civil and Environmental Engineering students also volunteered their time to help with
various aspects of this research. Robert Henderson and Ali Ayyoubi helped with the simulated evaluation
and design aspects of the critical area treatment device. Thanks are especially extended to Patty Barren,
Michael Richards, and Paul Latino, who helped Brian Robertson in the construction of the treatment
device that will be tested during the next project phase. Michelle Pickney and Ken Boyer also helped in
conducting many of the preliminary treatment column tests using soil and other media.

       Karyn Gordon, Marty Truscott, Keith Henderson, John Hess, Catherine Breen, and other
personnel of Henderson, Breen & Hess, Forked River, New Jersey, were instrumental in carrying out the
field sampling, coordinating with local agencies, and collecting necessary site data for the Stafford New
Jersey test sites. The City of Stafford and Ocean County, New Jersey, Public Works Departments and
the Stafford school board are especially acknowledged for their assistance for access to test sites.

       Richard Field, Chief of the Storm and Combined Sewer Pollution Control Program, EPA was the
Project Officer for this project and provided much valued direction during this research. Michael Brown
and Bill Vilkelis of his staff also provided important project assistance. Helpful comments from the report
reviewers are also gratefully acknowledged.
                                              VII

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                                           SECTION 1

                                 SUMMARY AND CONCLUSIONS


        Prior to urbanization, groundwater recharge resulted from infiltration of precipitation through
pervious surfaces, including grasslands and woods. This infiltrating water was relatively uncontaminated.
With urbanization, the permeable soil surface area through which recharge by infiltration could occur was
reduced. This resulted in much less groundwater recharge and greatly increased surface runoff. In
addition, the waters available for recharge generally carried increased quantities of pollutants. With
urbanization, new sources of groundwater recharge also occurred, including recharge from domestic
septic tanks, percolation basins and industrial waste injection wells, and from agricultural and residential
irrigation. This report addresses potential groundwater problems associated with stormwater toxicants,
and describes how conventional stormwater control practices can reduce these problems. This section is
a summary of the main findings, conclusions, and recommendations contained in the main report, where
more detailed and referenced discussions are contained.

        Section 2 of this report presents a summary of the characteristics of urban runoff, especially
from different source areas as monitored in an earlier phase of this EPA funded research. This
information is needed to identify critical sources of contaminants that may adversely affect ground and
surface receiving waters. These sources can either be controlled, or otherwise diverted from the
receiving waters. Section 3 is a literature review of potential groundwater impacts associated with
pollutants that may be found in stormwater. This information is based on literature describing
groundwater problem case studies associated with several classes of stormwater pollutants from different
types of source waters, including: stormwater, sanitary wastewater, agriculture operations, and some
industrial operations. Appendix A is an annotated  bibliography of this literature, including abstracts of the
references. The information  in Sections 2 and 3 can be used to identify which stormwater pollutants may
adversely affect groundwater, and where they may originate. Section 4 summarizes the available
treatment options for stormwater before discharge. This information can be used to suggest control
methods that should be used at critical source areas, or at an outfall, before groundwater discharge. If
treatment is not practicable for a specific area, then other control options may need to be considered,
especially pollution prevention or diversion of the runoff away from areas prone to groundwater
infiltration.

        The first year of this research project included conducting the literature review and preparation of
this report and the design and construction of a treatment device suitable for use at a class of critical
source areas, specifically automobile service areas (gas stations, vehicle repair shops, public works
maintenance yards, bus barns, etc.), and the installation of several inlet retro-fitted devices to control
runoff in residential and commercial areas. As part of this design effort, more than 20 samples were
collected from a residential area, a school bus maintenance area, and two public works yards in Stafford,
New Jersey. These samples were analyzed for a wide range of conventional and toxic pollutants that
could potentially affect groundwater quality (if the  water was infiltrated) and the design of the inlet
devices and special treatment device. This information was used in the design of the critical area
treatment device and will be included in a later report as part of the second year project effort.

        The second project phase will include monitoring three inlet and two source area treatment

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devices over an extended period of time for many compounds. Controlled tests for different filtering
media will also be conducted during the next project phase. The third project phase is expected to
include groundwater monitoring near an existing stormwater infiltrating trench gallery that has been
operating in Stafford, New Jersey, for several years.


CHARACTERISTICS OF URBAN RUNOFF

        Urban runoff is comprised of many different flow phases. These may include dry weather base
flows, stormwater runoff, combined sewer overflows (CSOs) and snowmelt. The relative magnitudes of
these discharges vary considerably based on a number of factors. Season (such as cold versus warm
weather, or dry versus wet weather) and land use have been identified as important factors affecting
base flow and stormwater runoff quality.

        Land development increases stormwater runoff volumes and pollutant concentrations.
Impervious surfaces, such as rooftops, driveways and roads, reduce infiltration of rainfall and runoff into
the ground and degrade runoff quality. The most important hydraulic factors affecting urban runoff
volume  (and therefore the amount of water available for groundwater infiltration) are the quantity of rain
and the extent of impervious surfaces directly connected to a stream or drainage system. Directly
connected impervious areas include paved streets, driveways, and parking areas draining to curb and
gutter drainage systems, and roofs draining directly to a storm or combined sewer pipe.
             and nutrient concentrations in stormwater are lower than in raw sanitary wastewater; they
are closer in quality to typically treated sanitary wastewaters. However, urban stormwater has relatively
high concentrations of bacteria, along with high concentrations of many metallic and some organic
toxicants.

Flow Phases

       Possibly 25 percent of all separate stormwater outfalls have water flowing in them during dry
weather,  and as much as 1 0 percent are grossly contaminated with raw sewage, industrial wastewaters,
etc. If stormwater is infiltrated before it enters the drainage system (such  as by using French drains,
infiltration trenches, grass swales, porous pavements or percolation ponds in upland areas) then the
effects of inappropriate contaminated discharges into the drainage system on groundwater will be
substantially reduced, compared to outfall infiltration practices. If outfall waters are to be infiltrated in
larger regional facilities, then the effects of contaminated dry weather flows will have to be considered.

Pathogenic Microorganisms

       Most of the effort in describing bacteria associated with urban runoff has involved fecal coliform
analyses, mainly because of its historical use in water quality standards. However, many researchers
have concluded that the fecal coliform test cannot be relied on to accurately assess the pathogenicity of
recreational waters receiving urban runoff from uncontaminated storm sewers. Pathogenic bacteria have
routinely  been found in urban runoff at many locations.

       Historically, fecal coliform standards of less than 200 organisms/100 ml_ have been
recommended because the frequency of Salmonella detection has been found to increase sharply at
fecal coliform concentrations greater than this value in waters receiving sanitary sewage discharges. The
occurrence of Salmonella biotypes in urban  runoff is generally low, with their reported densities ranging
from less than one, to a high of ten organism/100 ml_. However, numerous urban runoff studies have not
detected  any Salmonella. In addition, Salmonella observations in urban runoff have not correlated well
with fecal coliform observations. Salmonella is not usually considered a significant hazard in urban runoff

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because of the relatively large required infective dose and the low concentrations found in urban runoff.

        The evidence of low densities and required high infective doses for Salmonella cannot minimize
the health hazard of other pathogens that have been found in urban runoff (such as P. aeruginosa,
Shigella, or enteroviruses) that do not require ingestion, or only require very low infective doses. Shigella
species causing bacillary dysentery are one of the primary human enteric disease producing bacteria
present in water. Pseudomonas is reported to be the most abundant pathogenic bacteria organism in
urban runoff and streams. Several thousand Pseudomonas aeruginosa organisms per 100 mL have been
commonly found in many urban runoff samples. Relatively small populations of P. aeruginosa may be
capable of causing water contact health problems ("swimmers ear", and skin infections) and it is resistant
to antibiotics. Pathogenic E. coli can also be commonly found in urban runoff.

        Viruses may also be important pathogens in  urban runoff. Very small amounts of a virus are
capable of producing infections or diseases, especially when compared to the large numbers of bacteria
organisms required for infection. Viruses are usually detected, but at low levels, in urban receiving waters
and storm runoff.

Toxicants

        Nationwide testing has not indicated any significant regional differences in the toxicants
detected, or in their concentrations. However, land use (especially residential versus industrial areas) has
been found to be a significant factor in toxicant concentrations and yields. Concentrations of many urban
runoff toxicants have exceeded the EPA water quality criteria for human health protection by large
amounts.

        Pesticides  (a-BHC, y-BHC, chlordane and a-Endosulfan) are mostly found in dry weather flows
from residential areas, while heavy metals (As, Cd, Cr, Cu, Pb, and Zn) and other toxic materials
(pentachlorophenol, bis (2-ethylhexyl) phthalate, and the PAHs: chrysene, fluoranthene, phenanthrene,
and pyrene) are more prevalent in stormwater from industrial areas, although they are also commonly
found in runoff from residential and commercial areas. Many of the heavy metals found in industrial area
urban runoff were found at high concentrations during both dry weather and wet weather conditions.

Sources of Pollutants

        High bacteria populations have been found in sidewalk, road,  and some bare ground sheetflow
samples (collected  from locations where dogs would most likely be "walked"). Tables 1 and 2 summarize
toxicant concentrations and likely sources or locations having some of the highest concentrations found
during an earlier phase of this EPA funded research. The detection frequencies for the heavy metals are
all close to 100 percent for all source areas, while the detection frequencies for the organics shown
ranged from about  10 to 25 percent. Vehicle service areas had the greatest abundance of observed
organics, with landscaped areas having many of the observed organics.


CONSTITUENTS OF CONCERN

Nutrients

        Nitrates are one of the most frequently  encountered contaminants in groundwater. Groundwater
contamination of phosphorus has not been as widespread, or as severe, as for nitrogen compounds.

       Whenever nitrogen-containing compounds come into contact with soil, a potential for nitrate
leaching into groundwater exists, especially in rapid-infiltration wastewater basins, stormwater infiltration

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                   TABLE 1.  HEAVY METAL SOURCE AREA OBSERVATIONS
Toxicant

Cadmium
Chromium
Copper
Lead
Nickel
Zinc
Highest median
cone.
  8
100
160
 75
 40
100
Source

vehicle service area runoff
landscaped area runoff
urban receiving water
CSO
parking area runoff
roof runoff
Highest median
cone. (ng/L)
 220
 510
1250
 330
 130
1580
Source

street runoff
roof runoff
street runoff
storage area runoff
landscaped area runoff
roof runoff
                  TABLE 2 TOXIC ORGANIC SOURCE AREA OBSERVATIONS
Toxicant
Benzo (a) anthracene
benzo (b) fluoranthene
benzo (k) fluoranthene
Benzo (a) pyrene
Fluoranthene
Naphthalene
Phenanthrene
Pyrene

Chlordane
Butyl benzyl phthalate
Bis (2-chloroethyl) ether

Bis (2-chloroisopropyl) ether
1,3-Dichlorobenzene
Maximum
(H9/L)
60
226
221
300
128
296
69
102
Detection
Frequency (%)
12
17
17
17
23
13
10
19
                     2.2
                    128
                    204

                    217
                    120
               13
               12
               14

               14
               23
     Significant Sources

     gasoline, wood preservative
     gasoline, motor oils
     gasoline, bitumen, oils
     asphalt, gasoline, oils
     oils, gasoline, wood preservative
     coal tar, gasoline, insecticides
     oils, gasoline, coal tar
     oils, gasoline, bitumen, coal tar,
     wood preservative
     insecticide
     plasticizer
     fumigant, solvents, insecticides,
     paints, lacquers, varnishes
     pesticides
     pesticides
devices, and in agricultural areas. Nitrate has leached from fertilizers and affected groundwaters under
various turf grasses in urban areas, including golf courses, parks and home lawns. Significant leaching of
nitrates occurs during the cool, wet seasons.  Cool temperatures reduce denitrification and ammonia
volatilization, and limit microbial nitrogen immobilization and plant uptake. The use of slow-release
fertilizers is recommended in areas having potential groundwater nitrate problems. The slow-release
fertilizers include urea formaldehyde (UF), methylene urea, isobutylidene diurea (IBDU), and sulfur-
coated urea.

       Residual nitrate concentrations are highly variable in soil, due to soil texture, mineralization,
rainfall and irrigation patterns, organic matter content, crop yield, nitrogen fertilizer/sludge rate,
denitrification, and soil compaction. Nitrate is highly soluble (>1 kg/L) and will stay in solution in the
percolation water, after leaving the root zone, until it reaches the groundwater.

Pesticides

       Urban pesticide contamination of groundwater can result from municipal and homeowner use of
pesticides for pest control and their subsequent collection in stormwater runoff. Pesticides that have
been found in urban groundwaters include: 2,4-D, 2,4,5-T, atrazine, chlordane, diazinon, ethion,

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malathion, methyl trithion, silvex, and simazine. Heavy repetitive use of mobile pesticides on irrigated
and sandy soils likely contaminates groundwater. Fungicides and nematocides must be mobile in order
to reach the target pest and hence, they generally have the highest contamination potential. Pesticide
leaching depends on patterns of use, soil texture, total organic carbon content of the soil, pesticide
persistence, and depth to the water table.

        The greatest pesticide mobility occurs in areas with coarse-grained or sandy soils without a
hardpan layer, having low clay and organic matter content and high permeability. Structural voids, which
are generally found in the surface layer of finer-textured soils rich in clay, can transmit pesticides rapidly
when the voids are filled with water and the adsorbing surfaces of the soil matrix are bypassed. In
general, pesticides with low water solubilities, high octanol-water partitioning coefficients, and high
carbon partitioning coefficients are less mobile. The slower moving pesticides have been recommended
in areas of groundwater contamination concern. These include the fungicides iprodione and triadimefon,
the insecticides isofenphos and  chlorpyrifos and the herbicide glyphosate. The most mobile pesticides
include: 2,4-D, acenaphthylene, alachlor, atrazine, cyanazine, dacthal, diazinon, dicamba, malathion,
and metolachlor.

        Pesticides decompose in soil and water, but the total decomposition time can range from days to
years. Literature half-lives for pesticides generally apply to surface soils and do not account for the
reduced microbial activity found deep in the vadose zone. Pesticides with a thirty-day half life can show
considerable leaching. An order of magnitude difference in half-life results in a five to ten-fold difference
in percolation loss. Organophosphate pesticides are less persistent than organochlorine pesticides, but
they also are not strongly adsorbed by the sediment and are likely to leach into the vadose zone, and the
groundwater.

Other Organics

        The most commonly occurring organic compounds that have been found in urban groundwaters
include  phthalate esters (especially bis(2-ethylhexyl)phthalate) and phenolic  compounds. Other organics
more rarely found, possibly due to losses during  sample collection, have included the volatiles: benzene,
chloroform, methylene chloride, trichloroethylene, tetrachloroethylene, toluene, and xylene. PAHs
(especially benzo(a)anthracene, chrysene, anthracene and benzo(b)fluoroanthenene) have also been
found in groundwaters near industrial sites.

        Groundwater contamination from organics, like from other pollutants, occurs more readily in
areas with sandy soils and where the water table is near the land surface. Removal of organics from the
soil and recharge water can occur by one of three methods:  volatilization, sorption, and degradation.
Volatilization can significantly reduce the concentrations of the most volatile  compounds in groundwater,
but the rate of gas transfer from the soil to the air is  usually limited by the presence of soil water.
Hydrophobic sorption onto soil organic matter limits the mobility of less soluble base/neutral and acid
extractable compounds through organic soils  and the vadose zone. Sorption is not always a permanent
removal mechanism, however.  Organic re-solubilization can occur during wet periods following dry
periods. Many organics can be degraded by microorganisms, at least partially, but others cannot.
Temperature, pH, moisture content, ion exchange capacity of soil, and air availability may limit the
microbial degradation potential for even the most degradable organic.

Pathogenic Microorganisms

        Viruses have been detected in groundwater where stormwater recharge basins were located
short distances above the aquifer. Enteric viruses are more resistant to environmental factors than
enteric bacteria and they  exhibit longer survival times in natural waters. They can occur in potable and
marine waters in the absence of fecal coliforms.  Enteroviruses are also more resistant to commonly
used disinfectants than are indicator bacteria, and can occur in groundwater in the absence of indicator

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 bacteria.

        The factors that affect the survival of enteric bacteria and viruses in the soil include pH,
 antagonism from soil microflora, moisture content, temperature, sunlight, and organic matter. The two
 most important attributes of viruses that permit their long-term survival in the environment are their
 structure and very small size. These characteristics permit virus occlusion and protection within colloid-
 size particles. Viral adsorption is promoted by increasing cation concentration, decreasing pH and
 decreasing soluble organics. Since the movement of viruses through soil to groundwater occurs in the
 liquid phase and involves water movement and associated suspended virus particles, the distribution of
 viruses between the adsorbed and liquid phases determines the viral mass available for movement.
 Once the virus reaches the groundwater, it can travel laterally through the aquifer until it is either
 adsorbed or inactivated.

        The major bacterial removal mechanisms in soil are straining at the soil surface and at intergrain
 contacts, sedimentation, sorption by soil particles,  and inactivation. Because of their larger size than for
 viruses, most bacteria are therefore retained near the soil surface due to this straining effect. In general,
 enteric bacteria  survive in soil between two and three months, although survival times up to five years
 have been documented.

 Heavy Metals and Other Inorganic Compounds

        Heavy metals and other inorganic compounds in stormwater of most environmental concern,
 from a groundwater pollution standpoint, are aluminum, arsenic, cadmium, chromium, copper, iron, lead,
 mercury, nickel,  and zinc. However, the majority of these compounds, with the consistent exception of
 zinc, are mostly  found associated with the paniculate solids in stormwaters and are thus relatively easily
 removed through sedimentation practices. Filterable forms of the metals may also be removed by either
 sediment adsorption or are organically complexed with other particulates.

        In general, studies of recharge basins receiving large metal loads found that most of the heavy
 metals are removed either in the basin sediment or in the vadose zone. Dissolved metal ions are
 removed from stormwater during infiltration mostly by adsorption onto the near-surface particles in the
 vadose zone, while the particulate metals are filtered out at the soil surface. Studies at recharge basins
 found that lead, zinc, cadmium, and copper accumulated at the soil surface with little  downward
 movement over many years. However, nickel, chromium, and zinc concentrations have exceeded
 regulatory limits  in the soils below a recharge area at a commercial site. Allowing percolation ponds to go
 dry between storms can be counterproductive to the removal of lead from the water during recharge.
 Apparently, the adsorption bonds between the sediment and the metals can be weakened during the
 drying period.

        Similarities in water quality between runoff water and groundwater has show that there is
 significant downward movement of copper and iron in sandy and loamy soils. However, arsenic, nickel,
 and  lead did not  significantly move downward through the soil to the groundwater. The exception to this
 was  some downward movement of lead with the percolation water in sandy soils beneath stormwater
 recharge basins. Zinc, which is more soluble than iron, has been found in higher concentrations in
 groundwater than iron. The order of attenuation in the vadose zone from infiltrating stormwater is:  zinc
 (most mobile) > lead > cadmium > manganese > copper > iron > chromium > nickel > aluminum (least
 mobile).

 Salts

       Salt applications for winter traffic safety is a common practice in many northern areas and the
sodium and chloride, which are collected in the snowmelt, travel down through the vadose zone to the
groundwater with little attenuation.  Soil is not very effective at removing salts. Salts that are still in the

-------
percolation water after it travels through the vadose zone will contaminate the groundwater. Infiltration of
stormwater has led to increases in sodium and chloride concentrations above background
concentrations. Fertilizer and pesticide salts also accumulate in urban areas and can leach through the
soil to the groundwater.

       Studies of depth of pollutant penetration in soil have shown that sulfate and potassium
concentrations decrease with depth, while sodium, calcium, bicarbonate, and chloride concentrations
increase with depth. Once contamination with salts begin, the movement of salts into the groundwater
can be rapid. The salt concentration may not lessen until the source of the salts is removed.


TREATMENT OF STORMWATER


       Table 3 summarizes the filterable fraction of toxicants found in stormwater runoff sheet flows
from many urban areas found during an earlier phase of this EPA funded  research. Pollutants that are
mostly in filterable forms have a greater potential of affecting groundwater and are more difficult to
control using conventional stormwater control practices that mostly rely on sedimentation and filtration
principles. Luckily, most of the toxic organics and metals are associated with the non-filterable
(suspended solids) fraction of the wastewaters during wet weather. Likely exceptions include zinc,
fluoranthene, pyrene, and 1,3-dichlorobenzene, which may be mostly found in the filtered sample
portions. However, dry-weather flows in storm drainage tend to have much more of the toxicants
associated with filtered sample fractions.

   TABLE 3. FILTERABLE FRACTIONS OF STORMWATER TOXICANTS FROM SOURCE AREAS

Constituent                                   Filterable Fraction (%)
Cadmium                                      20 to 50
Chromium                                     <10
Copper                                        <20
Iron                                           small amount
Lead                                          <20
Nickel                                         small amount
Zinc                                           >50
Benzo (a) anthracene                            none found in filtered fraction
Fluoranthene                                   65
Naphthalene                                   25
Phenanthrene                                  none found in filtered fraction
Pyrene                                        95
Chlordane                                      none found in filtered fraction
Butyl benzyl phthalate                           irregular
Bis (2-chloroethyl) ether                         irregular
Bis (2-chlrorisopropyl)  ether                      none found in filtered fraction
1,3-dichlorobenzene                            75

       Sedimentation is the most common fate and control mechanism for paniculate related pollutants.
This would be common for most stormwater pollutants, as noted above. Particulate removal can occur in
many conventional stormwater control processes, including catchbasins, screens, drainage systems, and
detention ponds. Sorption of pollutants onto solids and metal precipitation increase the sedimentation
potential of these pollutants and also encourages more efficient bonding of the pollutants in soils,
preventing their leaching to groundwaters. Detention ponds are probably the most common management
practice for the control of stormwater runoff. If properly designed, constructed, and maintained, wet
detention ponds can be very effective in controlling a wide range of pollutants. The monitored

-------
 performance of wet detention ponds can be more than 90 percent removal of suspended solids, 70
 percent for BOD5 and COD, nutrient removals of about 60 to 70 percent, and heavy metal removals of
 about 60 to 95 percent. Catchbasins are very small sedimentation devices. Adequate cleaning can help
 to reduce the total solids and lead urban runoff yields by between 10 and 25 percent, and COD, total
 Kjeldahl nitrogen, total phosphorus, and zinc by between 5 and 10 percent. Other important fate
 mechanisms available in wet detention  ponds, but which are probably not as important in small sump
 devices such as catchbasins, include volatilization and photolysis. Biodegradation, biotransformation,
 and bioaccumulation (into plants and animals) may also occur in ponds.

        Upland infiltration  devices (such as infiltration trenches, porous pavements, percolation ponds,
 and grass roadside drainage swales) are located at urban source areas. Infiltration (percolation) ponds
 are usually located at stormwater outfalls, or at large paved areas. These basins, along with perforated
 storm sewers, can infiltrate flows and pollutants from all upland sources combined. Infiltration devices
 can safely deliver large fractions of the surface flows to groundwater, if carefully designed and located.
 Local conditions that can make stormwater infiltration inappropriate include steep slopes,  slowly
 percolating soils, shallow groundwater, and nearby groundwater uses. Grass filter strips may  be quite
 effective in removing particulate pollutants from overland flows. The filtering effects of grasses, along
 with increased  infiltration/recharge, reduce the particulate sediment load from urban landscaped areas.
 Grass swales are another  type of infiltration device and can be used in place of concrete curb and gutters
 in most land uses, except possibly strip  commercial and high density  residential areas. Grass swales
 allow the recharge of significant amounts of surface flows. Swales can also reduce the concentration of
 pollutants, due to filtration. Soluble and  particulate heavy metal (copper, lead, zinc, and cadmium)
 concentrations can be reduced by at least 50 percent, COD, nitrate nitrogen, and ammonia nitrogen
 concentrations can be reduced by about 25 percent, but only very small concentration reductions can be
 expected for organic nitrogen, phosphorus, and bacteria.

        Sorption of pollutants to soils is  probably the most significant fate mechanism of toxicants in
 biofiltration devices. Many  of the devices also use sedimentation and filtration to remove the  particulate
 forms of the pollutants from the water. Incorporation of the pollutants  onto soil with subsequent
 biodegradation, with minimal resultant leaching to the groundwater, is desired. Volatilization,  photolysis,
 biotransformation, and bioconcentration may also be significant in grass filter strips and grass swales.
 Underground french drains and porous pavements offer little biological activity to reduce toxicants.


 CONCLUSIONS

        This entire research project will  provide guidance on critical source treatment, especially for the
 protection of groundwater quality. Much  of the information will also be useful for surface water discharge
 analyses and modeling. Several reports will be periodically prepared during the project phase.

        Table 4 is a summary of the pollutants found in stormwater that may cause groundwater
 contamination problems for various reasons. This table does not consider the risk associated with using
 groundwater contaminated with these pollutants.  Causes of concern include  highly mobility (low sorption
 potential) in the vadose zone, high abundance (high concentrations and high detection frequencies) in
 stormwater, and high soluble fractions (small fraction associated with particulates which would have little
 removal potential using conventional stormwater sedimentation controls) in the stormwater. The
 contamination potential is the lowest rating of the influencing factors. As an example, if no pretreatment
 was to be used before percolation through surface soils, the mobility and abundance criteria are most
 important. If a compound was mobile, but was in  low abundance (such as for VOCs), then the
 groundwater contamination potential would be low. However, if the compound was mobile and was also
 in high abundance (such as for sodium chloride, in certain conditions), then the groundwater
contamination would be high. If sedimentation pretreatment was to be used before infiltration, then some
of the pollutants will likely be removed before infiltration.  In this case, all three influencing  factors

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  TABLE 4.  GROUNDWATER CONTAMINATION POTENTIAL FOR STORMWATER POLLUTANTS
Nutrients
Pesticides
Other
organics
Pathogens
Heavy metals
Salts
             Compounds
nitrates
Mobility
(sandy/low
organic
soils)

mobile
                             Abundance
                             in storm-
                             water
            Fraction
            filterable
                                          low/moderate   high
2,4-D
Y-BHC (lindane)
malathton
atrazine
chlordane
diazinon
mobile
intermediate
mobile
mobile
intermediate
mobile
tow
moderate
tow
tow
moderate
tow
                                                       likely low
                                                       likely low
                                                       likely low
                                                       likely low
                                                       very low
                                                       likely low
enterovi ruses
Shigella
Pseudomonas
  aeruginosa
protozoa

nickel
cadmium
chromium
lead
zinc

chloride
mobile
low/inter.
low/inter.

low/inter.

low
low
inter./very low
very low
low/Yerytow

mobile
likely present
likely present
very high
high
moderate
moderate
high
low
moderate
moderate
high

seasonally
high
low
moderate
very low
very tow
high

high
           Contamination
           potential -
           (surface infill.
           and no
           pretreatment)
           low/moderate

           tow
           moderate
           tow
           tow
           moderate
           tow
VOCs
1 ,3-dichloro-
benzene
anthracene
benzo(a)
anthracene
bis (2-ethylhexyl)
phthalate
butyl benzyl
phthalate
fluoranthene
fluorene
naphthalene
pentachlorophenol
phenanthrene
pyrene
mobile
tow

intermediate
intermediate

intermediate

tow

intermediate
intermediate
low/inter.
intermediate
intermediate
intermediate
tow
high

tow
moderate

moderate

low/moderate

high
tow
tow
moderate
moderate
high
very high
high

moderate
very tow

likely low

moderate

high
likely low
moderate
likely low
very tow
high
low
tow

tow
moderate

moderate

tow

moderate
tow
tow
moderate
moderate
moderate
high
low/moderate
low/moderate
                                          likely present   moderate    low/moderate
low
tow
low/moderate
tow
tow

high
Contamination
potential -
(surface infill
with sediment-
ation)
low/moderate

tow
tow
tow
tow
low
tow

tow
tow

tow
tow

low

tow

moderate
tow
tow
tow
tow
moderate

high
low/moderate
low/moderate

low/moderate

tow
tow
tow
tow
low

high
Contamination
potential (if
sub-surface inj.
with minimal
pretreatment)
low/moderate

tow
moderate
low
tow
moderate
tow

tow
high

tow
moderate

moderate

low/moderate

high
tow
tow
moderate
moderate
high

high
high
high

high

high
tow
moderate
moderate
high

high
(mobility, abundance in stormwater, and soluble fraction) would be considered important. As an example,
chlordane would have a low contamination potential with sedimentation pretreatment, while it would have
a moderate contamination potential if no pretreatment was used. In addition, if subsurface
infiltration/injection was used instead of surface percolation, the compounds would most likely be more
mobile, making the abundance criteria the most important, with some regard given to the filterable
fraction information for operational considerations.

        This table is only appropriate for initial estimates of contamination potential because of the
simplifying assumptions made, such as the likely worst case mobility measures for sandy soils having
low organic content. If the soil was clayey and had a high organic content, then most of the organic
compounds would  be less mobile than shown on this table. The abundance and filterable fraction
information is generally applicable for warm weather stormwater runoff at residential  and commercial
area outfalls. The concentrations and detection frequencies would likely be  greater for critical source

-------
 areas (especially vehicle service areas) and critical land uses (especially manufacturing industrial areas).

        The stormwater pollutants of most concern (those that may have the greatest adverse impacts
 on groundwaters) include:

        • nutrients: nitrate has a low to moderate groundwater contamination potential for both surface
 percolation and subsurface infiltration/injection practices because of its relatively low concentrations
 found in most stormwaters. If the stormwater nitrate concentration was high, then the groundwater
 contamination potential would  likely also be high.

        • pesticides: lindane and chlordane have moderate groundwater contamination potentials for
 surface percolation practices (with no pretreatment) and for subsurface injection (with minimal
 pretreatment). The groundwater contamination potentials for both of these compounds would likely be
 substantially reduced with adequate sedimentation pretreatment.

        • other organics: 1,3-dichlorobenzene may have a high groundwater contamination potential for
 subsurface infiltration/injection (with minimal pretreatment). However, it would likely have a lower
 groundwater contamination potential  for most surface percolation practices because of its relatively
 strong sorption to vadose zone soils.  Both pyrene and fluoranthene would also likely have high
 groundwater contamination potentials for subsurface infiltration/injection practices, but lower
 contamination potentials for surface percolation  practices because of their more limited mobility through
 the unsaturated zone (vadose  zone). Others (including benzo(a)anthracene, bis (2-ethylhexyl) phthalate,
 pentachlorophenol, and phenanthrene) may also have moderate groundwater contamination potentials, if
 surface percolation with no pretreatment,  or subsurface injection/infiltration is used. These compounds
 would have low groundwater contamination potentials if surface infiltration was used with sedimentation
 pretreatment. Volatile organic carbons (VOCs) may also have high groundwater contamination potentials
 if present in the stormwater (likely for some industrial and commercial facilities and vehicle service
 establishments).

        • pathogens: enteroviruses likely  have a high groundwater contamination potential for all
 percolation practices and subsurface infiltration/injection practices, depending on their presence in
 stormwater (likely, especially if contaminated with sanitary sewage). Other pathogens, including Shigella,
 Pseudomonas aeruginosa, and various protozoa, would also have high groundwater contamination
 potentials if subsurface infiltration/injection practices are used without disinfection. If disinfection
 (especially by chlorine or ozone) is used, then disinfection byproducts  (such as trihalomethanes or
 ozonated bromides) would have high groundwater contamination potentials.

        • heavy metals: nickel  and zinc would likely have high groundwater contamination potentials if
 subsurface infiltration/injection  was used.  Chromium and lead would have moderate groundwater
 contamination potentials for subsurface infiltration/injection practices. All metals would likely have low
 groundwater contamination potentials if surface infiltration was used with sedimentation pretreatment.

        • salts: chloride would  likely have a high groundwater contamination potential in northern  areas
 where road salts are used for traffic safety, irrespective of the pretreatment, infiltration or percolation
 practice used.

        Pesticides have been mostly  found in urban runoff from residential areas, especially in dry
 weather flows associated with landscaping irrigation runoff. The other organics, especially the volatiles,
 are mostly found in industrial areas. The phthalates are found in all areas. The PAHs are also found in
 runoff from all areas, but they are in higher concentrations and occur more frequently in industrial areas.
 Pathogens are most likely associated with sanitary sewage contamination of storm drainage systems, but
several bacterial  pathogens are commonly found in surface runoff in residential areas. Zinc is mostly
                                               10

-------
found in roof runoff and other areas where galvanized metal comes into contact with rainwater. Salts are
at their greatest concentrations in snowmelt and early spring runoff in northern areas.

        The control of these compounds will require a varied approach, including source area controls,
end-of-pipe controls, and pollution prevention. All dry weather flows should be diverted from infiltration
devices because of their potentially high concentrations of soluble heavy metals, pesticides, and
pathogens. Similarly, all runoff from manufacturing industrial areas should also be diverted from
infiltration devices because of their relatively high concentrations of soluble toxicants. Combined sewer
overflows should also be diverted because of sanitary sewage contamination. In areas of extensive snow
and ice, winter snowmelt and early spring runoff should also be diverted from infiltration devices.

        All other runoff should include pretreatment using sedimentation processes before infiltration, to
both minimize groundwater contamination and to prolong the life of the infiltration device (if needed).
This pretreatment can take the form of grass filters, sediment sumps, wet detention ponds, etc.,
depending on the runoff volume to be treated and other site specific factors. Pollution prevention can
also play an important role in minimizing groundwater contamination problems, including reducing the
use of galvanized metals, pesticides, and fertilizers in critical areas. The use of specialized treatment
devices, such as being developed and tested during this research, can also play an important role in
treating runoff from critical source areas before these more contaminated flows commingle with cleaner
runoff from other areas. Sophisticated treatment schemes, especially the use of chemical processes or
disinfection, may not be warranted, except in special cases,  especially considering the potential of
forming harmful treatment by-products (such as THMs and soluble aluminum).

        The use of surface percolation devices (such as grass swales and percolation ponds) that have a
substantial depth of underlying soils above the groundwater, is preferable to using subsurface infiltration
devices (such as dry wells, trenches orfrench drains, and especially injection wells), unless the runoff
water is known to be relatively free of pollutants. Surface devices are able to take greater advantage of
natural soil pollutant removal processes. However, unless all percolation devices are carefully designed
and maintained, they may not function properly and may lead to premature hydraulic failure or
contamination of the groundwater.


RECOMMENDATIONS

        It has been commonly suggested that, with a reasonable degree of site-specific design
considerations to compensate for soil characteristics, infiltration can be very effective in controlling both
urban runoff quality and quantity problems. This strategy encourages infiltration of urban runoff to
replace the natural infiltration capacity lost through urbanization and to use the natural filtering and
sorption of capacity of soils to remove pollutants. However, potential groundwater contamination through
infiltration of some types of urban runoff requires some restrictions. Infiltration of urban runoff having
potentially high concentrations of pollutants that may pollute groundwater requires adequate
pretreatment, or the diversion of these waters away from infiltration devices. The following general
guidelines for the infiltration of stormwater and other storm drainage effluent are recommended in the
absence of comprehensive site-specific evaluations:

        • Dry weather storm drainage effluent should be diverted from infiltration devices because of
their probable high concentrations of soluble heavy metals, pesticides, and pathogenic microorganisms.

        • Combined sewage overflows should be diverted from infiltration devices because of their poor
water quality, especially high pathogenic microorganism concentrations, and high clogging potential.

        • Snowmelt runoff should also be diverted from  infiltration devices because of its potential for
                                               11

-------
having high concentrations of soluble salts.

        • Runoff from manufacturing industrial areas should also be diverted from infiltration devices
because of its potential for having high concentrations of soluble toxicants.

        • Construction site runoff must be diverted from stormwater infiltration devices (especially
subsurface devices) because of its high suspended solids concentrations which would quickly clog
infiltration devices.

        • Runoff from other critical source areas, such as vehicle service facilities and large parking
areas, should at least receive adequate pretreatment to eliminate their groundwater contamination
potential before infiltration.

        • Runoff from residential areas (the largest component of urban runoff from most cities) is
generally the least polluted urban runoff flow and should be considered for infiltration. Very little
treatment  of residential area stormwater runoff should be needed before infiltration, especially if surface
infiltration  is through the use of grass swales. If subsurface infiltration (french drains, infiltration trenches,
dry wells, etc.) is used, then some pretreatment may be needed, such as by using grass filter strips, or
other surface filtration devices.

Recommended Stormwater Quality Monitoring to Evaluate Potential Groundwater Contamination

        Most past stormwater quality monitoring has not been adequate to completely evaluate
groundwater contamination potentials. The following list shows the parameters that are recommended if
stormwater contamination potential needs to be considered, or infiltration devices are to be used. Other
analyses are appropriate for additional monitoring objectives (such as evaluating surface water
problems). In addition, all phases of urban runoff should be sampled, including stormwater runoff, dry
weather flows, and snowmelt.

        • Contamination potential:
                Nutrients (especially nitrates)
                Salts (especially chloride)
               - VOCs (if expected in the runoff, such as from manufacturing industrial or
                vehicle service areas, could screen for VOCs with purgable organic carbon, POC,
                analyses)
               - Pathogens (especially enteroviruses, if possible, along with other pathogens such as
                Pseudomonas aeruginosa, Shigella, and pathogenic protozoa)
               - Bromide and total organic carbon, TOC (to estimate disinfection by-product generation
                potential, if disinfection by either chlorination or ozone is being considered)
               - Pesticides, in both filterable and total sample components (especially lindane and
                chlordane)
               - Other organics, in both filterable and total sample components (especially 1,3
                dichlorobenzene, pyrene, fluoranthene, benzo (a) anthracene, bis (2-ethylhexyl)
                phthalate, pentachlorophenol, and phenanthrene)
                Heavy metals, in both filterable and total sample components (especially chromium,
                lead, nickel, and zinc)
        • Operational considerations:
                Sodium, calcium, and magnesium (in order to calculate the sodium adsorption ratio to
                predict clogging of clay soils)
               - Suspended solids (to determine the need for sedimentation pretreatment to prevent
                clogging)
                                               12

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                                          SECTION 2

                            CHARACTERISTICS OF URBAN RUNOFF
        Unfortunately, some stormwaters from urban areas may be badly polluted. These waters may
pose a potential threat to both surface and subsurface receiving waters. In order to protect these
receiving water resources, treatment before discharge is likely needed. This report section summarizes
urban runoff quality. This water quality data can be compared to the information presented in the
previous section to identify which urban runoff waters need treatment to protect groundwaters. Many
studies  have investigated stormwater quality, with the EPA's Nationwide Urban Runoff Program (NURP)
(EPA 1983) providing the largest and best known data base. Unfortunately, the extensive analytical
results reported by NURP, and  other studies, have not included all of the pollutants that are likely to
cause the greatest concern in groundwater, as described in the next report section.

        Urban runoff is comprised of many different flow types. These include dry weather base flows,
stormwater runoff, combined sewer overflows (CSOs) and snowmelt. The relative magnitudes of these
discharges vary considerably based on a number of factors. Season (especially cold versus warm
weather) and land use have been identified as important factors affecting base flow and stormwater
runoff quality, respectively (Pitt and McLean 1986). This section briefly summarizes a number of
different observations of runoff quality for these different phases and land uses, along with summaries of
observations of source area flows contributing to these combined discharges. This information can be
used to identify the best stormwater candidates for infiltration controls, and which ones to avoid.


STORMWATER CHARACTERISTICS

        Land development increases stormwater pollutant concentrations and volumes. Impervious
surfaces, such as rooftops, driveways and roads, reduce infiltration of rainfall and runoff into the ground
and degrade runoff quality. Maintenance of landscaped  areas further degrades runoff quality. The
average runoff volume from developing subdivisions has been reported to be more than ten times
greater than that of typical pre-development agricultural areas (Madison, et al.  1979).

        Factors affecting runoff water volume (and therefore the amount of water available for
groundwater infiltration) include rainfall  quantity and intensity, slope, soil permeability, land cover,
impervious area and depression storage. Research during the  Nationwide Urban Runoff Program
(NURP) showed that the most important hydraulic factors affecting urban runoff volume were the
quantity of rain and the extent of impervious surfaces directly connected to a stream or drainage system
(EPA 1983). Directly connected impervious areas include paved streets, driveways, and parking areas
draining to curb and gutter drainage systems, or roofs draining directly to a storm sewer.

       Table 5 presents historical stormwater quality data (APWA 1969) while Table 6 is a summary of
the Nationwide Urban Runoff Program stormwater data  collected from about 1979 through 1982  (EPA
1983). BODs and  nutrient concentrations in stormwater  are lower than associated values for raw sanitary
                                              13

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                       TABLE 5. CHARACTERISTICS OF STORMWATER RUNOFF

1.




2.


3.

4.




5.
6.
7.
8.
9.
10.


11.
City
East Bay Sanitary District:
Oakland, California
Minimum
Maximum
Average
Cincinnati, Ohio
Maximum Seasonal Means
Average
Los Angeles County
Average 1962-63
Washington, D.C.
Catch-basin samples during storm
Minimum
Maximum
Average
Seattle, Washington
Oxney, England
Moscow, U.S.S.R.
Leningrad, U.S.S.R.
Stockholm, Sweden
Pretoria, South Africa
Residential
Business
Detroit, Michigan
BODs
(mq/L)


3
7,700
87

12
17

161


6
625
126
10
100a
186-285
36
17-80

30
34
96-234
Total Solids
(mg/L.)


726

1,401

260


2,909






2,045
1 ,000-3,500a
14,541
30-8,000



310-914
Suspended
Solids Chlorides
(mq/L) (mg/L)


16 300
4,400 10,260
613 5,100


227

199


26 11
36,250 160
2,100 42








1 02-21 3b
COD
(mg/L)






110
111











18-3,100

29
28

aMaximum
bMean
Source: APWA 1969

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            TABLE 6. MEDIAN STORMWATER POLLUTANT CONCENTRATIONS FOR ALL SITES BY LAND USE
                                    (Nationwide Urban Runoff Program, NURP)
Pollutant
BOD5, mg/L
COD, mg/L
TSS, mg/L
Total Kjeldahl Nitrogen, jxg/L
NO2 - N + NO3 - N, ng/L
Total P, ng/L
Soluble P, ng/L
Total Lead, |j.g/L
Total Copper, ng/L
Total Zinc, ng/L
Resid
Median
10.0
73
101
1900
736
383
143
144
33
135
ential
COV1
0.41
0.55
0.96
0.73
0.83
0.69
0.46
0.75
0.99
0.84
Mixed L
Median
7.8
65
67
1288
558
263
56
114
27
154
and Use
COV
0.52
0.58
1.14
0.50
0.67
0.75
0.75
1.35
1.32
0.78
Comrr
Median
9.3
57
69
1179
572
201
80
104
29
226
lercial
COV
0.31
0.39
0.85
0.43
0.48
0.67
0.71
0.68
0.81
1.07
Open/N
Median
-
40
70
965
543
121
26
30
-
195
onurban
COV
--
0.78
2.92
1.00
0.91
1.66
2.11
1.52
-
0.66
^COV: coefficient of variation = standard deviation/mean

Source: EPA 1983

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wastewater; they are closer in quality to typically treated sanitary wastewaters. However, urban
stormwater has relatively high concentrations of bacteria, along with high concentrations of many
metallic and some organic toxicants. As will be shown later, land use and source areas (parking areas,
rooftops, streets, landscaped areas, etc.) all have important effects on stormwater runoff quality.

Urban Runoff Bacteria and their Associated Public Health Significance

        Most of the effort in describing bacteria characteristics of urban runoff has involved fecal coliform
analyses, mainly because of its historical  use in water quality  standards. Fecal coliform bacteria
observations have long been used as  an indicator of sanitary  sewage contamination and therefore has
been used as an indicator of possible  pathogenic microorganism contamination (Field and O'Shea 1992).
Fecal streptococci analyses are also relatively common for urban runoff. Unfortunately, relatively few
analyses of specific pathogenic microorganisms have been made for urban runoff.

        The fecal coliform test is not specific for any one coliform type, or groups of types, but instead
has an excellent positive correlation for coliform bacteria derived from the intestinal tract of warm blooded
animals (Geldreich, et al. 1968). The fecal coliform test measures Escherichia coll as well as all other
coliforms that can ferment lactose at 44.5°C and are found  in  warm blooded fecal discharges. Geldreich
(1976) found that the fecal coliform test represents over 96 percent of the coliforms derived from human
feces and from 93 to 98 percent of those discharged in feces  from other warm blooded animals, including
livestock, poultry, cats, dogs, and rodents. In many urban runoff studies, all of the fecal coliforms were E.
co// (Quresh and Dutka 1979). Field and O'Shea (1992) conclude that the fecal coliform test cannot be
relied on to accurately assess the pathogenicity of recreational waters receiving urban runoff from
uncontaminated storm sewers. The fecal  streptococci test is sensitive to all of the intestinal Streptococci
bacteria from warm blooded animal feces (Geldreich and Kenner 1969).

        Pathogenic bacteria have been found in urban runoff  at many locations and are probably from
several different sources (Field, et  al. 1976; Oliveria, et al. 1977; Qureshi and  Dutka 1979; Environment
Canada 1980; Pitt 1983; Pitt and McLean 1986; and  Field and O'Shea 1992). Table 7 summarizes the
occurrence of various pathogenic bacteria types found in  urban stormwaters at Burlington, Ontario;
Milwaukee; and Cincinnati. The observed ranges of concentrations and percent isolations of these
biotypes vary significantly from site to  site and at the same  location for different times. However, it is seen
that many of the potentially pathogenic bacteria biotypes can  be present in urban stormwater runoff. The
occurrence of Salmonella biotypes is generally low and their reported density is usually less than one
organism/100 ml_. Pseudomonas aeruginosa are frequently encountered at densities greater than ten
organisms/100 ml_.

        Some authors do not feel that urban runoff presents a significant health problem. Olivieri, et al.
(1977) do not believe that urban runoff constitutes a major health problem because of the large numbers
of viable bacteria cells that must be consumed to establish  an infection for many of the pathogens found
in urban runoff. For urban runoff, it may be impossible to consume  enough bacteria cells to establish the
infective dose. The importance of urban runoff in disease transmission in the Ottawa area was also
questioned by  Gore and Storrie/Proctor and Redfern (1981). They stated that  little or no correlation was
found between fecal coliform indicator bacteria and pathogenic bacteria in Ottawa stormwater runoff and
local receiving waters. They further stated that the currently applied objectives in Ontario for fecal
coliforms for body contact recreation are neither universal nor absolute standards relating to disease or
infection. They concluded that these numeric objectives should be reviewed for their applicability to the
local swimming beaches. However, Field and O'Shea (1992)  pointed out that the evidence of low
densities and required high infective doses for some  pathogens cannot minimize the health hazard of
other pathogens that  have been found in urban runoff (such as P. aeruginosa, Salmonella typhosa,
                                               16

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     TABLE 7. PATHOGENIC MICROORGANISMS FOUND IN URBAN STORMWATER (organisms/1 OOmL)

City, Province/               Staphylo-
State

Burlington,
Ontario



Milwaukee, Wl

Cinncinnati,
OH




catchment/
land-use
Aldershot
Plaza

Malvem
Road
highway
runoff
business
district
residential
area
rural area

coccus Pseudomonas
aureus aeruginosa
14-3,000


<1-740

all all
<1,000 <1,000







Salmonella
S. seftenberg
& S. newport
isolated
100% negative

45% positive








Streptococci







79% positive n

80% positive2

87% positive 3


Reference
Qureshi and
Dutka, 1979

Qureshi and
Dutka, 1979
Gupta, et al,
1981
Geldreich and
Kenner, 1969
Geldreich and
Kenner, 1969
Geldreich and
Kenner, 1969
"* Strep, bacteria types found:
2Strep. bacteria types found:
3Strep. bacteria types found:
S. bovis/S. equinus (2%)
Atypical S. faecalis (1 %)
S. faecalis liquifaciens (18%)

S. thompson: 4,500/1 OOmL

S. bovis/S. equinus (0.5%)
Atypical S. faecalis (1 %)
S. faecalis liquifaciens (18%)

S. bovis/S. equinus (0.5%)
Atypical S. faecalis (0.2%)
S. faecalis liquifaciens (12%)
                                                 17

-------
Shigella, or enteroviruses) that do not require ingestion, or only require very low infective doses.

Urban Runoff Salmonella Observations--
        Salmonella has been reported in some, but not all, urban stormwaters. Oureshi and Dutka (1979)
frequently detected Salmonella in southern Ontario stormwaters. They did not find any predictable
patterns of Salmonella isolations as they were found throughout the various sampling periods. Olivieri, et
al. (1977) frequently found Salmonella in Baltimore runoff, but at relatively low concentrations. Typical
concentrations were from five to 300  Salmonella organisms per ten liters. The concentrations of
Salmonella were about ten times higher in the Baltimore stormwater samples than in the urban stream
receiving the runoff. They also did not find any marked seasonal variations in Salmonella concentrations.
Almost all of the stormwater samples that had fecal  coliform concentrations greater that 2000
organisms/100 mL had detectable Salmonella concentrations. However, about 27 percent of the samples
having fecal coliform concentrations less than 200 organisms/100 mL had detectable Salmonella.

        Quite a few urban runoff studies did not detect Salmonella. Schillinger and Stuart (1978) found
that Salmonella isolations were not common in a Montana subdivision study and that the isolations did
not correlate well with fecal coliform concentrations. Environment Canada (1980) stated that Salmonella
were virtually absent from Ottawa storm drainage samples obtained in 1979. They concluded that
Salmonella are seldom present in significant numbers in Ottawa urban runoff. The types of Salmonella
found in southern Ontario were S. thompson and  S. tvphimuriumvar.  Copenhagen (Qureshi and Dutka
1979).

        Olivieri, et al. (1977) stated that the primary human enteric disease producing Salmonella
biotypes associated with the ingestion of water include S. typhi (typhoid fever), S. paratyphi (paratyphoid
fever), and Salmonella species (salmonellosis). These biotypes are all rare, except for Salmonella. The
dose of Salmonella required to produce an infection in a healthy adult is quite large (approximately
100,000 organisms). However, more  sensitive individuals, such as children and the elderly, are much
more susceptible to disease. The salmonellosis health hazard associated with urban streams is believed
to be small because of this relatively  large infective dose. If two liters of stormwater having typical
Salmonella concentrations (ten Salmonella organisms per/ten liters) is ingested, less than 0.001 of the
required infective dose would be ingested. If a worse case Salmonella stormwater concentration of
10,000 organisms/ten liters occurred, the ingestion of  20 liters of stormwater would be necessary for an
infective dose. They stated that the low concentrations of Salmonella, coupled with the unlikely event of
consuming enough stormwater, make the Salmonella  health hazard associated with  urban runoff small.

        Geldreich (1965) recommended a fecal coliform standard of 200 organisms/100 mL because the
frequency of Salmonella detection increased sharply at fecal coliform concentrations greater than this
value. Setmire and Bradford (1980) stated that the National Academy of Sciences recommended a fecal
coliform standard of 70/100 mL in waters with shellfish harvesting to restrict Salmonella concentrations in
edible tissues. However, Field, et al.  (1976) concluded that the use of indicator bacteria to protect
Salmonella ingestion is less meaningful in stormwater runoff than in other waters.

Urban Runoff Shigella Observations-
        Olivieri, et al. (1977) stated that there  is circumstantial evidence that Shigella is present in urban
runoff and receiving waters and could present  a significant health hazard. There have been problems in
isolating and quantifying  Shigella bacteria. Shigella species causing bacillary dysentery are one of the
primary  human enteric disease producing bacteria agents present in water. The infective dose of Shigella
necessary to cause dysentery is quite low (10 to 100 organisms). Because of this low required infective
dose and the assumed presence of Shigella in urban waters, it may be a significant health hazard
associated with urban runoff.
                                              18

-------
Urban Runoff Pseudomonas aeruginosa Observations--
        Pseudomonas is reported to be the most abundant pathogenic bacteria organism in urban runoff
and streams (Olivieri, et al. 1977). Pitt and McLean (1986) found P. aeruginosa populations of several
thousand organisms per 100 ml_ in many urban runoff samples. No information could be found
concerning the problems associated with ingestion of P. aeruginosa contaminated drinking waters.
However, relatively small populations of P. aeruginosa may be capable of causing water contact health
problems ("swimmers ear", and skin infections) and it is resistant to antibiotics.

Other Urban Runoff Pathogen Observations-
        E. co// and Vibrio cholerae are disease producing pathogens associated with the ingestion of
water. The cholera pathogen is quite rare, but E. coli is more common in urban runoff. The required
infective oral dose of both of these pathogens is about 10** organisms for healthy adults (Olivieri, et al.
1977).

        Viruses may also be significant pathogens in urban runoff. Very small amounts of a virus are
capable of producing infections or diseases, especially when compared to the large numbers of bacteria
organisms required for infection (Berg 1965). Olivieri, et al. (1977) stated that viruses are usually
detected at low levels in urban receiving waters and storm runoff.

Summary of Urban Runoff Pathogenic Microorganism Observations-
        Many potentially pathogenic bacteria biotypes may be present in urban runoff. Because of the
low probability of direct ingestion of urban runoff, many of the potential human diseases associated with
these biotypes are not likely to occur in normal receiving waters. The pathogenic organisms of most
concern in urban runoff (and therefore that have received the most attention) are usually associated with
skin infections and body contact in recreation waters. The most significant stormwater biotype causing
skin infections would be Pseudomonas aeruginosa. This biotype has been detected frequently in  most
urban runoff studies in concentrations that may cause potential infections. Shigella may be present in
urban runoff and receiving waters. This pathogen, when ingested in low numbers, can cause dysentery. A
number of other pathogenic microorganisms have been periodically reported in urban runoff.

Significant Stormwater Toxicants

        Stormwater research has quantified some inorganic and organic hazardous and toxic substances
frequently found in urban runoff. The NURP data (Table 8), collected from mostly residential areas
throughout the U.S., did not indicate any significant regional differences in the substances detected, or in
their concentrations (EPA 1983). However, the residential and industrial data obtained by Pitt and
McLean (1986) in Toronto found significant concentration and yield differences for these two distinct land
uses and for dry weather and wet weather urban runoff flows.

       The concentrations of many of these toxic pollutants exceeded the U.S. EPA water quality
criteria for human health protection by large amounts. As  an  example, typical standards for PAHs in
surface waters used as drinking water supplies are 2.8 ng/L (EPA 1986). As shown on Table 8, urban
runoff concentrations of chrysene (600 to 10,000 ng/L), fluoranthene (300 to 21,000 ng/L), phenanthrene
(300 to 10,000 ng/L) and pyrene (300 to 16,000 ng/L) (four of the most common PAHs found in urban
runoff) have been reported to be from 100 to as much as several thousand times greater than this
criteria.

       Table 9 lists the toxic and hazardous substances that have been found in more than 10 percent
of the industrial and residential urban runoff samples analyzed (Galvin and Moore 1982; EPA 1983; and
Pitt and McLean 1986). As noted above, available NURP data do not reveal toxic urban runoff conditions
                                              19

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                        TABLE 8. SUMMARY OF NURP PRIORITY POLLUTANT ANALYSES1
                      (Only those compounds found in greater than 10% of outfall samples are shown)

Pesticide
a-BHC
f - BHC (lindane)
Chlordane
a - Endosulfan
Metals and Cyanide
Antimony
Arsenic
Beryllium
Cadmium
Chromium
Copper
Cyanides
Lead
Mercury
Nickel
Selenium
Zinc
PCBs and Related Compounds
(none detected in greater than 1% of all samples)
Haloqenated Aliphatics
Methylene chloride
Ethers
(None detected in any of the samples)
Monocvclic Aromatics
(None detected in greater than 6% of all samples)
Phenols and Cresols
Phenol
Pentachlorophenol
4-nitro phenol
Phthalate Esters
bis (2-ethylhexyl) phthalate
Polvcvclic Aromatic Hydrocarbons
Chrysene
Fluoranthene
Phenanthrene
Pyrene
Frequency of
Detection
%
20
15
17
19
13
52
12
48
58
91
23
94
10
43
11
94
11
14
19
10
22
10
16
12
15
Range of Detected
Concentrations
(ua/L)
0.0027 to 0.1
0.007 to 0.1
0.01 to 10
0.008 to 0.2
2.6 to 23
1 to 51
1 to 49
0.1 to 14
1 to 190
1 to 100
2 to 300
6 to 460
0.6 to 1.2
1 to 182
2 to 77
10 to 2400
5to15
1 to13
1 to 115
1 to 37
4 to 62
0.6 to 10
0.3 to 21
0.3 to 10
0.3 to 16
1 Based on 121 samples from 17 cities

Source: EPA 1983.
                                                   20

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              TABLE 9. HAZARDOUS AND TOXIC SUBSTANCES FOUND IN URBAN RUNOFF*
Haloginated Aliphatics
     1,2,-dichlorethene
     Methylene chloride
     Tetrachloroethylene
                                                     Residential
                                                       Areas
                   Industrial
                     Areas
                       x
                       x
                       x
Phthalate Esters
     Bis (2-Ethylene) phthalate
     Butylbenzyl phthalate
     Diethyl phthalate
     Di-N-Butyl phthalate
x
x
                       X

                       X
                       X
Polvcvclic Aromatic Hydrocarbons
     Phenanthrene
     Pyrene
Other Volatiles
     Benzene
     Chloroform
     Ethylbenzene
     N-Nitro-sodimethylamine
     Toluene
                       x
                       x
                       X
                       X
                       X
Heavy Metals
     Aluminum
     Chromium
     Copper
     Lead
     Zinc
                       x
                       x
                       x
                       x
                       x
Pesticides and Phenols
     BHC
     Chlordane
     Dieldrin
     Endosulfan sulfate
     Endrin
     Isophorone
     Methoxychlor
     PCB-1254
     PCB-1260
     Pentachlorophenol
     Phenol
x
x
x
x
x
x
x
x
x
x
x
x
x
*Substances found in at least 10 percent of the stormwater samples analyzed

Sources:  Galvin and Moore (1982), EPA (1983), and Pitt and McLean (1986).
                                                21

-------
significantly different from different parts of the U.S. (EPA 1983). The pesticides shown were mostly
found in urban runoff from residential areas, while heavy metals and other hazardous materials were
much more prevalent in industrial areas. Urban runoff dry weather base flows may also be significant
contributors of hazardous and toxic pollutants. Lindane (gamma-BHC) and dieldrin may be common in
residential dry weather storm sewer flows, while PCBs may be common in industrial dry weather storm
sewer flows. Many of the heavy metals found in industrial area urban runoff were found at high
concentrations during both dry weather and wet weather conditions.


COMBINED  SEWAGE CHARACTERISTICS

       Combined sewage is made up of sanitary wastewater during dry-weather flow conditions, but
also includes stormwater during wet-weather flow conditions. Because of the relatively slow sewage flow
rates during dry weather, many combined sewage systems experience deposition of solids in the
sewerage system. When stormwater enters the system during wet weather, this deposited material is
flushed from the system. This flush therefore typically has greater pollutant concentrations than either
separate stormwater or separate sanitary sewage (Moffa 1989). Tables 10 through 14 summarize various
aspects of combined sewage. Table 12 compares bacteria densities of combined sewage with separate
stormwater in Baltimore (Olivieri, et al. 1977). This table shows very little difference in the bacteria
densities of these two sample types. Tables 13 and 14 show heavy metal and other toxicant
concentrations in combined sewage. Pitt and Barren (1990) found all of the heavy metals investigated in
New York City combined sewage samples, but only two of the base-neutral organic compounds were
found in more than one of the 20 samples analyzed. None of the base-neutrals were detected (at a
detection limit of about 1 /^g/L) in the filtered sample portions, but most of the metals were found in the
filtered samples.


RELATIVE CONTRIBUTIONS OF URBAN RUNOFF FLOW PHASES

       Tables 15 and  16 summarize Toronto residential/commercial and industrial urban runoff
characteristics during both warm and cold weather (Pitt and McLean 1986). These tables show the
relative importance of wet weather and dry weather flows coming from separate stormwater systems. If
urban runoff is to be directed to an outfall infiltration device, then the dry weather flows will also be
present at the outfalls.  Possibly 25 percent of all separate stormwater outfalls have water flowing in them
during dry weather, and as much as 10 percent are grossly contaminated with raw sewage, industrial
wastewaters, etc. (Pitt, et al. 1993). The EPA's Stormwater Permit program requires municipalities to
conduct stormwater outfall surveys to identify, and then  correct, inappropriate discharges into separate
storm drainage. However, it can be expected that substantial outfall contamination will exist for many
years. If stormwater is  infiltrated before it enters the drainage system  (such as by using French drains,
infiltration trenches, grass swales, porous pavements or percolation ponds in upland areas) then the
effects of contamination problems in the drainage system on groundwater will be substantially reduced. If
outfall waters are to be infiltrated in larger regional facilities, then these periods of dry weather flows will
have to be considered.

       Similar problems occur in areas having substantial snowfalls. Table 16 summarizes Toronto
snowmelt and cold weather baseflow characteristics (Pitt and McLean 1986). The bacteria densities
during cold weather are substantially than during warm weather, but are still relatively high (EPA 1983).
However, chloride concentrations and dissolved solids are much higher during cold weather. Early spring
stormwater events also contain high dissolved solids concentrations (Bannerman, personal
communication, Wl DNR). Unfortunately, upland infiltration devices do not work well during cold weather
due to freezing soils. Outfall flows occur under ice into receiving waters (including detention ponds) and
may enter regional infiltration devices if not specifically  diverted.
                                              22

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                                         TABLE 10. POLLUTANT CONCENTRATIONS IN COMBINED SEWER OVERFLOWS
to
U)
Average Pollutant Concentration (mg/L)

Des Moines, Iowa
Milwaukee, Wisconsin
New York City, New York
Newtown Creek
Spring Creek
Poissy, France c
Racine, Wisconsin
Rochester, New York
Average (not weighted)
Range
Syracuse, New York^
Hartford, Connecticut6
TSS
413
321

306
347
751
551
273
370
273-551
306
727
VSS
117
109

182
-
387
154
-
140
109-182
98.4
-
BOD
64
59

222
111
279
158
65
115
59-222
64.3
33
COD
--
264

481
358
1005
-
-
367
264-481
-
319
Kjeldahl
nitrogen
—
4.9

-
--
-
-
2.6
3.8
2.6-4.9
2.83
6.20(NHs)
Total
nitrogen
4.3
6.3

-
16.6
43
-
-
9.1
4.3-16.6
--
~
P04-P
1.86
1.23

--
4.5^
17^
2.78
-
1.95
1.23-2.78
0.35b
~
OPO4-P Lead
1.31
0.86

0.60
--
..
0.92
0.88 0.14
1.00 0.37
0.86-1.31 0.14-0.60
„
-
Fecal
coliforms3
-
-

-
-
--
201
1140
670
201-1140
1,407
2,600
             a1000 organisms/100ml.
             ^Total P (not included in average)
             cNot included in average because of high strength of municipal sewage when compared to the United States.
             ^O'Brien & Gere, 1979.  "Combined Sewer Overflow Abatement Program," a report to Onondaga County, NY.
             eCalocerinos & Spina, 1988. "Hartford Combined Sewer Overflow Facility Plan," a report to the Metropolitan District Commission, Hartford, CT.
             Ref. EPA 600/8-77-014  Urban Stormwater Management and Technology, Update and Users Guide.

             Source: Moffa 1989

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           TABLE 11. SELECTED COMBINED SEWER OVERFLOW BACTERIA DATA
                                    (organisms/1 OOmL)
                    City (reference)
   Fecal
  Conforms
   Fecal
   strep
Ottawa
(Ontario Ministry of the Environment 1983)

Toronto
(Ontario Ministry of the Environment 1982)

Detroit
(Geldreich1976)

Selected Nationwide Data
(Field & Struzeski 1972)
5x105-9x106


    10b

  10b-107


2x104-2x107
    105
2x104-2x10fc>
                                          24

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               TABLE 12. GEOMETRIC MEAN DENSITIES OF SELECTED PATHOGENS AND INDICATOR MICROORGANISMS
                                   IN BALTIMORE STORMWATER AND COMBINED SEWAGE
Sampling
Station
Stoney Run
Glen Avenue
Howard Park
Jones Falls
Bush Street
Northwood
Sample
Type
combined
combined
combined
combined
stormwater
stormwater
Enterovirus
PFU/
10 liters
190
75
280
30
6.9
170
Salmonella sp.
MPN/
10 liters
30
24
140
25
30
5.7
P. aeruginosa
MPN/
10 liters
1300
3300
5200
6600
2000
590
Step/7, aureus
MPN/
10 mL
12
14
36
40
120
12
TC
MPN/100mL
(x104)
4.8
24
120
29
38
3.8
FC
MPN/100mL
(x103)
19
81
450
120
83
6.9
FS
no./100 mL
(x104)
4.1
66
24
28
56
5
Enterococci
no./1 OOmL
(x104)
1.4
21
5.9
8.7
12
2.1
Source: Olivieri, et al. 1977

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                     TABLE 13.  CONCENTRATIONS OF HEAVY METALS
                           IN COMBINED SEWER OVERFLOWS

                                        Copper          Zinc            Lead
            Land Use Type                fcg/L) _ (jxg/L)
COMBINED SEWER OVERFLOW

   Medium Density Residential1                77           191               93
   High Density Residential2                  48           185               84
   Residential/Commercial                   100           255              135
   Light Industrial                            58           136               47
   Heavy Industrial                    _ 98           447              223

   Mean for All Land Uses                    76           242              116


1 Medium Density Residential         3 to 8 dwelling units per acre
^High Density Residential            9 and more dwelling units per acre

Source: Johnson 1990
                                          26

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             TABLE 14.  NEW YORK CITY COMBINED SEWER OVERFLOW QUALITY SUMMARY
                                       (average of observed values)
                                          total sample
                                        mean   detection
                                     of observ.  frequency

Microtox toxicity (I35, % light decrease)     59      20 of 20
pH                                     6.8      20 of 20
Suspended solids (mg/L)                  94      20 of 20
Turbidity (NTU)                          22      20 of 20
Particle size (median, microns)            50      20 of 20

Base Neutrals (1 ng/L detection limit)
Nitrobenzene
Isophorone
Bis(2-chloroethyl) ether
1,3-Dichlorobenzene
Naphthalene
Diethyl phthalate
Fluorene
Di-n-butyl phthalate
Phenanthrene
Benzyl butyl phthalate
Fluoranthene
Bis(2-ethyl hexyl) phthalate
Pyrene
Di-n-octyl phthalate
Benzo(a) anthracene
Chrysene

Pesticides (0.3 jig/L detection limit)
BHC                                    0.3      1 of 20
ODD                                    1.2      1of20
Chlordane                               0.5      1 of 20

Heavy Metals (1 (ig/L detection limit)
Aluminum (5 ng/L detection limit)           1890    20 of 20
Cadmium (0.1 ng/L detection limit)         2.8      20 of 20
Chromium                               21.7     20 of 20
Copper                                 93.5     20 of 20
Lead                                    45.3     20 of 20
Nickel                                  15.3     20 of 20
Zinc                                    116     20 of 20
26.5
10.4
15.5
22
7.7
103
9.3
33.2
33.2
82.3
6.6
11500
15.3
42.6
10.9
8.2
1 of 20
1 of 20
1 of 20
1 of 20
1 of 20
1 of 20
1 of 20
4 of 20
1 of 20
1 of 20
1 of 20
5 of 20
1 of 20
1 of 20
1 of 20
1 of 20
     filtered sample
  mean     detection
of observ.   frequency
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    nd
    204
    0.9
    13.9
    12.8
    3.5
    8.8
    35.5
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
Oof 20
14 of 20
20 of 20
9 of 20
20 of 20
14 of 20
19 of 20
20 of 20
             percent
             filterable 2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
11
32
64
14
8
58
31
(1) A split sample portion was also filtered through a 0.45nm membrane filter before analysis to determine the
filterable pollutant concentrations.

(2) The "percent filterable" is the percentage of the total sample concentration associated with the filtered sample
portion:  (filtered sample conc.Aotal sample conc.)X100.

(3) nd: not detected

   Source: Pitt and Barren 1990
                                                  27

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        TABLE 15. MEDIAN CONCENTRATIONS OBSERVED AT TORONTO OUTFALLS
                              DURING WARM WEATHER1
Constituent
(mg/L unless noted)
Stormwater volume (m^/ha/season)
Baseflow volume (m^/ha/season)
Total residue
Total dissolved solids (TDS)
Suspended solids (SS)
Chlorides
Total phosphorus
Phosphates
Total Kjeldahl nitrogen
(organic N plus NH^)
Ammonia nitrogen
Chemical oxygen demand (COD)
Fecal coliform bacteria (#/1 OOmL)
Fecal strep, bacteria (#/100mL)
Pseudo. aeruginosa bacteria (#/1 OOmL)
Arsenic
Cadmium
Chromium
Copper
Lead
Selenium
Zinc
Phenolics (ng/L)
a - BHC (ng/L)
Y - BHC (Lindane) (ng/L)
Chlordane (ng/L)
Dieldrin (ng/L)
Polychlorinated biphenois (PCBs) (ng/L)
Pentachlorophenol (PCP) (ng/L)
Warm W
Base
Residential
—
1700
979
973
<5
281
0.09
<0.06
0.9
<0.1
22
33,000
2,300
2,900
<0.03
<0.01
<0.06
0.02
<0.04
<0.03
0.04
<1.5
17
5
4
4
<20
280
'eather
rlow
Industrial
--
2100
554
454
43
78
0.73
0.12
2.4
<0.1
108
7,000
8,800
2,380
<0.03
<0.01
0.42
0.05
<0.04
<0.03
0.18
2.0
<1
<2
<2
<5
<20
50
Warm W
Storms
Residential
950
--
256
230
22
34
0.28
0.02
2.5
<0.1
55
40,000
20,000
2,700
<0.03
<0.01
<0.06
0.03
<0.06
<0.03
0.06
1.2
1
<1
<2
<2
<20
70
'eather
water
Industrial
1500
-
371
208
117
17
0.75
0.16
2.0
<0.1
106
49,000
39,000
11,000
<0.03
<0.01
0.32
0.06
0.08
<0.03
0.19
5.1
3.5
<1
<2
<2
33
705
(1) Warm weather samples were obtained during the late spring, summer, and early fall months when the
air temperatures were above freezing and no snow was present.

Source: Pitt and McLean 1986
                                        28

-------
        TABLE 16. MEDIAN CONCENTRATIONS OBSERVED AT TORONTO OUTFALLS
                               DURING COLD WEATHER2
Constituent
(mg/L unless noted)
Stormwater volume (m^/ha/season)
Baseflow volume (nrVha/season)
Total residue
Total dissolved solids (TDS)
Suspended solids (SS)
Chlorides
Total phosphorus
Phosphates
Total Kjeldahl nitrogen
(organic N plus NH^)
Ammonia nitrogen
Chemical oxygen demand (COD)
Fecal coliform bacteria (#/1 OOmL)
Fecal strep bacteria (#/1 OOmL)
Pseudo. aeruginosa bacteria (#/1 OOmL)
Cadmium
Chromium
Copper
Lead
Zinc
Phenolics (mg/L)
a - BHC (ng/L)
Y - BHC (Lindane) (ng/L)
Chlordane (ng/L)
Dieldrin (ng/L)
Pentachlorophenol (PCP) (ng/L)
Cold W<
Base
Residential
—
1100
2230
2210
21
1080
0.18
<0.05
1.4
<0.1
48
9800
1400
85
<0.01
<0.01
0.02
<0.06
0.07
2.0
NA*
NA
NA
NA
NA
Bather
low
Industrial
—
660
1080
1020
50
470
0.34
<0.02
2.0
<0.1
68
400
2400
55
<0.01
0.24
0.04
<0.04
0.15
7.3
3
NA
NA
NA
NA
ColdW
Snow
Residential
1800
—
1580
1530
30
660
0.23
<0.06
1.7
0.2
40
2320
1900
20
<0.01
<0.01
0.04
0.09
0.12
2.5
4
2
11
2
NA
sather
melt
Industrial
830
- •
1340
1240
95
620
0.50
0.14
2.5
0.4
94
300
2500
30
0.01
0.35
0.07
0.08
0.31
15
5
1
2
NA
40
(1) Cold weather samples were obtained during the winter months when the air temperatures were
commonly below freezing. Snowmelt samples were obtained during snowmelt episodes and when rain
fell on snow.

(2) NA:  not analyzed

Source: Pitt and McLean 1986
                                         29

-------
POLLUTANT CONTRIBUTIONS FROM DIFFERENT URBAN SOURCE AREAS

       Limited source area sheetflow quality data is available from several studies conducted in
California, Washington, Nevada, Wisconsin, Illinois,  Ontario, Colorado, New Hampshire, New York, and
Alabama since 1979. A relatively large amount of parking and roof runoff quality data has been obtained
from all of these locations, but only a few of these studies evaluated a broad range of source areas or
land uses. This information can  be used to identify which upland areas can be controlled by direct
infiltration, which ones would require significant pretreatment before infiltration, and which ones should
not be discharged to the groundwater because of potentially high concentrations of problem pollutants
that may not be adequately treated. The major urban source area categories that have been studied
include:

       • roofs
       • paved parking areas
       • paved storage areas
       • unpaved parking and storage areas
       • driveways
       • streets
       • landscaped areas
       • undeveloped areas
       • freeway paved lanes and shoulders
       • vehicle  service areas
Tables 17 through 20, summarize much of the data available describing urban area runoff pollutants
from these source areas for different land uses and seasons.

       Lead and zinc concentrations are generally the highest in sheetflows from paved parking areas
and streets, with some high zinc concentrations also found in roof drainage samples. High bacteria
populations have been found in sidewalk, road, and some bare ground sheetflow samples (collected from
locations where dogs would most likely be "walked").

       Pentachlorophenol was detected (400 to 500 ng/L concentrations) in four of the five industrial
source area samples analyzed for priority pollutants in Toronto (Pitt and McLean 1986). These samples
were collected from an industrial subdrainage area and from a paved storage yard. Two of the five
industrial source area priority pollutant sheetflow samples analyzed also had detectable PCBs (80  and
190 ng/L), alpha-BHC (8 and 10 ng/L), and gamma-BHC (2 and 10 ng/L) concentrations.

       Some of the sheetflow contributions observed at these locations were not sufficient to explain the
concurrent concentrations observed in runoff at outfalls. The low chromium surface sheetflow
concentrations and the high outfall concentrations at the Toronto industrial area, as an example,
indicated a high potential for direct industrial wastewater  connections to the storm drainage system.
Chromium was rarely detected in any sheetflow samples, but was commonly found in potentially problem
concentrations at the industrial outfall. Similarly, most of the fecal coliform populations observed in
sheetflows were significantly lower than those observed at the outfall.

       The following paragraphs  briefly summarize  likely sources of important pollutants in urban areas:

       Cadmium was commonly detected by Pitt and Barron (1990) in almost all stormwater source
area runoff samples. They found the highest median concentration (8 ng/L) in vehicle service area
runoff, while a street runoff sample had the highest concentration observed (220 ng/L).  Durum (1974)
                                              30

-------
                         TABLE 17. TORONTO COLD WEATHER SNOWMELT SOURCE AREA SHEETFLOW QUALITY
                                               (median observed concentrations, mg/L)


Source Area

Industrial
Previous Areas:
Grass/open areas
Unpaved storage/parking
Impervious Areas:
Sidewalks
Paved pk./storage & driveways
Road gutters
Residential/Commerical
Pervious Areas:
Grass/open areas
Impervious Areas:
Sidewalks
Paved pk., driveways & loading
Paved roads
Road gutters
Roadside grass swales


Total
Solids


390
2925

1050
1690
1320


94

390
918
890
530
380
Total
Dissolved
Solids
(TDS)


282
1000

200
349
575


78

29
274
166
190
155

Suspended
Solids
(SS)


77
2105

847
392
625


40

281
380
284
152
50



Chlorides


100
113

48
260
230


4.0

6.4
81
56
25
37


Total
Phosphorus


0.33
1.1

0.45
0.55
0.60


0.29

0.63
0.64
0.30
0.54
0.59



Phosphates


0.10
0.46

0.20
0.18
0.15


0.20

0.38
0.08
0.06
0.28
0.17



TKN


1.4
5.3

1.6
3.8
1.8


1.2

2.6
2.5
1.8
2.3
1.8



Ammonia


<0.1
0.2

<0.1
<0.1
<0.1


0.4

2.6
<0.1
<0.1
<0.1
0.1



COD


47
160

63
135
230


26

98
110
140
66
40
Source: Pitt and McLean 1986
                                                                                                    (continued)

-------
TABLE 17. (Continued)


Source Area
Industrial
Previous Areas:
Grass/open areas
Unpaved storage/parking
Impervious Areas:
Sidewalks
Paved pk./storage & driveways
Road gutters
Residential/Commerical
Pervious Areas:
Grass/open areas
Impervious Areas:
Sidewalks
Paved pk., driveways & loading
Paved roads
Road gutters
Roadside grass swales
Fecal
coliforms
Fecal
strep.
Pseudo.
aerug.
| (counts/1 OOmL)


<20
<100

<50
<100
<100


<20
75

<20
50
60
60


100
100

<50
450
100


350
600

200
200
4600
1300


<20
<20

<20
<20
<20


<10
<20

10
<10
<10
<10

Cadmium



<0.005
0.011

<0.005
<0.005
<0.005


<0.005
<0.005

<0.005
<0.005
<0.005
<0.005

Chromium



0.01
0.07

0.02
0.02
0.05


<0.01
<0.01

0.02
0.01
0.01
<0.01

Copper



0.01
0.13

0.11
0.05
0.12


<0.01
0.02

0.04
0.05
0.02
0.01

Lead



0.01
0.26

0.09
0.20
0.45


0.04
0.15

0.23
0.26
0.12
0.05

Zinc



0.06
0.51

0.47
0.40
0.66


0.02
0.16

0.23
0.26
0.09
0.08
phenolics
(W/L)



3.0
9.0

3.7
4.0
9.0


1.4
1.4

2.6
3.2
1.8
1.6

-------
                               TABLE 18. TORONTO WARM WEATHER SOURCE AREA SHEETFLOW QUALITY
                                                (median observed concentrations, mg/L)

Source Area

Industrial
Previous Areas:
Bare ground
Unpaved driveway & pk/storage
Impervious Areas:
Roofs
Sidewalks
Paved pk./storage & driveways
Paved Roads
Residential
Pervious Areas:
Bare ground
Impervious Areas:
Roofs
Sidewalks
Paved driveways & parking
Paved roads

Total
Solids


488
1148
113
580
315
992


1240
44
49
952
185
Total
Dissolved
Solids
(TDS)


240
420
107
145
112
188


436
39
28
78
51

Suspended
Solids
(SS)


247
805
5
435
202
871


807
<3
20
687
136


Chlorides


400
1160
MA1
257
240
220


250
56
63
92
79

Total
Phosphorus


0.62
1.09
<0.05
0.82
0.9
0.9


0.20
<0.04
0.8
0.62
0.49


Phosphates


0.20
0.09
<0.02
0.03
0.06
0.06


0.66
<0.02
0.64
<0.02
0.03


TKN


2.7
2.8
1.7
4.7
3.1
3.5


1.3
0.8
1.1
2.2
1.6


Ammonia


0.2
<0.1
0.35
<0.1
0.15
<0.1


0.5
0.1
0.3
<0.1
<0.1


COD


40
247
55
98
132
326


66
36
62
67
66
NA1: not analyzed

Source: Pitt and McLean 1986
                                                                                                      (continued)

-------
TABLE 18. (Continued)


Source Area

Industrial
Previous Areas:
Bare ground
Unpaved driveways & pk/storage
Impervious Areas:
Roofs
Sidewalks
Paved pk./storage & driveways
Paved roads
Residential/Commerical
Pervious Areas:
Bare ground
Impervious Areas:
Roofs
Sidewalks
Paved driveways & parking
Paved roads
Fecal
coliforms




Fecal
strep.
Pseudo.
aerug.
(1 ,000
counts/1 OOmL)


3.3
26

1
55

.6

2.8
19



MA

0
11
2
4

.5

.0
.8


43
6.2

0.6
3.6
0.4
8.5


NA

0.9
1.8
1.0
7.9


2.1
0.5

0.06
3.7
0.7
5.1


NA

0.1
0.6
0.4
0.1

Cadmium




<0.03
<0.004

<0.004
<0.004
<0.004
<0.004


<0.001

<0.003
<0.004
<0.004
<0.004

Chromium




<0.15
<0.06

<0.06
<0.06
<0.06
<0.06


<0.01

<0.03
<0.06
<0.06
<0.03

Copper




<0.1
0.13

0.015
0.03
0.05
0.13


0.02

0.01
0.02
0.05
0.02

Lead




<0.3
0.25

<0.04
0.04
0.19
0.51


0.03

<0.03
0.08
0.35
0.13

Zinc




0.05
0.50

0.07
0.06
0.34
0.59


0.04

0.31
0.06
0.45
0.16
phenolics
(MA.)




0.8
9.0

1.2
8.7
8.6
14.7


<0.4

2.8
8.6
11.8
6.3

-------
             TABLE 19. OTTAWA SHEETFLOW BACTERIA CHARACTERISTICS
                      (August 15 and September 23, 1981 samples)

Fecal
Coliforms



Fecal
Strep.




geometric mean (#/1 OOmL)
min(#/100mL)
max (#/1 OOmL)
number of observations
geometric mean (#/100mL)
min(#/100mL)
max (#/1 OOmL)
number of observations
rooftop
runoff

85
10
400
4
170
20
3,600
4
vacant land
and park
runoff

5,600
360
79,000
7
16,500
12,000
57,000
7
parking lot
runoff

2,900
200
19,000
6
1 1 ,900
1,600
40,000
6
gutter
flow

3,500
500
10,000
7
22,600
1,800
1 ,200,000
7
Source: Pitt 1983
                                       35

-------
                              TABLE 20. BIRMINGHAM, AL, SOURCE AREA SHEETFLOW QUALITY (AVERAGE CONCENTRATIONS OF OBSERVED COMPOUNDS)

                                      Residential Roofs      Commercial Roofs

     Pollutant OigA. unless noted)           total     filtered       total     filtered
Microlox toxfclry (I35, % light decrease)         41
pH (pH units.)                              6.5
Suspended solids (mgA.)                   26.8
Turbidity (NTU)                             4.2
Particle  size (median, microns)              22.4

Metals:
Aluminum                                 1910
Cadmium                                  6.4
Chromium                                12.2
Copper                                     46
Lead                                       51
Nickel                                      15
Zinc                                      476

Base-Neutrals:
Bis(2-chloroethyl) ether                      4.5
1,3-Olchlorobenzene                         14
Bis(chlorobopropl) ethei                      46
Bls(2-chloroethoxy) methane
Hexachloroethane
Napthalene
Dl-n-butyl phthalate                          6.6
Acenaphylene
Ruorene
Phenanthrena
Anthracene
Bend butyl phthalale
Fluorantheno
Bbp-elhyl hex!) phthalate
Pyrene
Benzo(a) anthracene
Chrysene
Benzo(b) fluoranthene                        4.4
Benzo(k) fluoranthene                        3.4
Benzo(a) pyrene                            9.3
Benzo(g,h,i) perytene

Pesticide*:
alpha BHC
delta BHC
AWrln
DDT                                       9.4
Chlordane                                0.37
Mathoxychlor
Endrin
 362
0.14
0.86
 2.8
 438
 3.8
            29
           6.2
             3
           3.3
            27
 152
0.43
 170
 5.1
28.9
24.4
 181
29.2
29.8
22.9

18.9
62.7
           7.7
           8.2
          35.2
          15.3

           9.5
           5.8
          24.7
            89
          74.1
           100

           100
            0.2
           0.15
  82
0.08
                     0.85
                      128
                       5.9
                       7.9
                      4.6
            1.9
lustrlal Roofs

totaJ filtered
20
8
5
4
14
319 167
1.2 0.47
6.2 0.75
240 (.6
37.8 0.66
4
33.5 21.B
5.5



12.3 5.7


6 3.8




7.3
3.3
13.3

0.29
0.39
0.29
ResldTlrtat. Streets

total filtered
9.5
72
14.5
5.5
30
181 155
0.46 0.31
3 0.9
10 1.34
15.8 2.73
2.23
37.5 37.5








153










Industrial Street!

total filtered
34
7.9
65.5
43.1
27
4520 1250
55.7 0.25
11 1.6
410 42
56.3 0.9
19.9
67.5 27.3
42 1
(.6 1.1





0.5

0.6 0.6


3.9
42
5.1




ResM. Pvd Parking

total filtered
37
7.1
15.5
15.3
35
2500 610
35.3 02
290
285 2.1
68.7 1
35.3
64 55.5

21.4 5.1
41


20.S
1 .8 1 .9
47.4 2.7

40.3 9.8
28.3
14.9
66.4
5.9
39.4
10.1



Com/Insl Pvd
Parking
total fin
30
6.8
41
7.9
34.4
558
2.6
19.6
39.3
45.4
33.1
178
2.4
8
40.2
11.4
9.4
2
3.1
2.4

5.5
2.5

3.8
6.6
5.5





ated





94.4
0.5
1.5
15.8
1.5
2.8
144

2.5


1.3














                                0.66
                                                                         0.31
                                                                                              0.23
                                                                                                                                                   0.78
                                                                                                                 OJ6
                                                                                                                 0.17
                                                                                                                                                             0.18
Blanks: all samples had non-delectable quantities
          Heavy mstals: 1 (ig/L detection limits, except lor 5 (ig/L for aluminum and 0.1 u,g/L for cadmium.
          Bass neutrals: general)/ 1 (ig/L detection limits.
          Pesticides: generally 0.3 |ig/L detection limits.
Source: Pitt and Barren 1990.
                                                                                                                                                                            (continued)

-------
                                                                   TABLE 20. (CONTINUED)
       Polkitant (ugA. unless noted)

Microtox toxiety (1,,, % fight decrease)
pH (pH unte)
Suspended solids (mgAJ
Turbidity (NTU)
Particle size (median, microns)

Metils:
Aluminum
Cadmium
Chromium
Copper
Lead
Nickel
Zinc

B«se-Neutnls:
Bisp-chbroelhyl) ethar
1,3-Dichlorobenzene
B'B(chlorolsopropl) ether
Bb(2-chloroethoxy) methane
Hexadifcroethane
Napthalene
Dl-n-biityl phthalate
Acenaphylene
Fluorene
Phenanthrene
Anthracene
Benzl butyl phthalate
Ruoranthene
Bbp-ethyl hexQ phthalate
Pyrene
Benzo(a) anthracene
Chrysene
Benzo(b) fluoranthena
Benzo(k) fluoranlhene
Banzo(a) pyrene
Benzo(g.h,() perylane

Pesticides:
alpha BHC
delta BHC
Aldrln
DDT
Chlordane
Methoxychlor
Endrln
IroL Unpvd
Parking
total filtered
29
82
391
392
38
11600 370

15 1.5
390 2.3
6S.5 0.9
30
81.5 18
12.2


















Indus. Unpvd
Parking
total filtered
18
7.9
170
42.4
42.7
3140 1070
1
6.5 1.9
13.3 3.6
28 1.7
73.3
28 JJ 19



















Com/Indus Pvd
Storage
total filtered
45
fi.1
15
10.2
47.3
514 267
4.6 12
33.8 3
16.7 0.9
21 1.7
30.6
48 392












10.7






Indus Unpvd
Loading Docks
Vehicle Service
Storage
total
46
62
152
81.7
23.8
2940
6.7
100
458
155
69
2740

3.6









1.3

2





filtered
_
.
.
.
•
52.9
22
9.4
305
2.8
17.8
7.8

3.3

















total filtered
30
7.8
40
16.5
31.7
777 7.7
1.4 0.44
17.1
21.6 S3
55.1 1.1
6.7 0.8
36.8 222



















total
25
12
23.8
10.2
37
705
62
74.3
135
63.4
42
105
9.4
28.8
47.3

11.9
28.4
0£
0.6
2.6
9J
10.5
15.9

18.1
14.3
5.4
39.7
23.9
362
filtered
.
-
.
•
•
136
023
03
6.8
14
6.6
72.8
4.9
10.6


11.1
16.8
0.8


2.6
42
1.7

1.9





Landscaped
A/eas
total
24
6.6
37.6
55
292
2310
029
94.4
94.4
28.5
382
263
11.7
13.5
17.4
3.8

10 J


6
45
26
62

2.4
112

6.3
12.7
112
filtered
.
•
.
-
•
1210
024
1.8
3.3
0.7

165

2.6

1.6







0.7







0.89
                 0.43
                                   028
                                   0.18

-------
stated that concentrations of the carbonate and hydroxide forms of cadmium, with pH values equal to or
less than 7, are relatively high and that the U.S. Public Health Service (USPHS) standard of 10 ^g/L may
occur in many stable water systems, including both surface and groundwaters.

        Chromium was detected by Pitt and Barron (1990) at concentrations above 1 ng/L in almost all of
the stormwater source area sheetflow and receiving water samples analyzed. Landscaped area samples
had the highest median total chromium concentrations observed (100 |ig/L), while a roof runoff sample
had the highest sample concentration observed (510 i^g/L). Phillips and Russo (1978) stated that in
water, trivalent (+3) chromium exists as a complex, colloid or precipitate, depending on pH. The more
toxic hexavalent (+6) chromium form is usually present only as an ion and would therefore not be directly
removable through filtering or sedimentation practices.

        Copper was detected by Pitt and Barron (1990) at concentrations greater than 1 ng/L in
practically all  of the stormwater samples analyzed. Urban creek samples contained the greatest median
concentrations (160 ng/L), while a street runoff sample had the highest copper concentration observed
(1250 ng/L). Callahan, et at. (1979) stated that copper in  unpolluted waters occurs mostly as a carbonate
complex and  in  polluted waters forms complexes with organic materials.  Pitt and Amy (1973) found that
inorganic copper is mostly found with valence states of plus one and  plus two in natural water systems
near pH 7. The common inorganic copper forms at these pH include copper combined with sulfides,
sulfates, oxides, hydroxides, cyanides, and iodide. Phillips and Russo (1978) stated that alkalinity  and
pH are believed to be the major factors controlling copper speciation. Callahan, et al. (1979) stated that
copper speciation  with organics is most important in polluted waters.  Cu++ is especially likely to form
complexes with humic materials.

       The EPA (1976) stated that the ferrous form of iron can persist in waters void of dissolved
oxygen, and originates usually from anaerobic groundwaters or from  mine drainage. Iron can exist in
natural organometallic, humic, and colloidal  forms. Black or brown "swamp waters" may contain iron
concentrations of several milligrams per liter in the presence or absence of dissolved oxygen, but this
iron form has  little effect on aquatic life because it is complexed and relatively inactive chemically  or
physiologically.

        Pitt and Barron (1990) found lead at concentrations greater than 1 ng/L in all of the stormwater
runoff and CSO samples analyzed. Vehicle service area  samples contained the greatest median
concentrations (75 (xg/L), while a storage area runoff sample had the highest lead concentration
observed (330 ng/L). Lead  exists in nature mainly as lead sulfide  (Galena) (EPA 1976). Other common
natural forms  of lead are lead carbonate (Cerussite), lead sulfate (Anglesite) and lead chlorophosphate
(Pyromorphite). Stable complexes result from the interaction of lead with organic materials. The toxicity
of lead in water  is  affected by pH,  hardness, organic materials and the presence of other metals. Pitt and
Amy (1973) reported that most inorganic lead in runoff water systems near pH 7 exist in the plus 2  or
plus 4 valence states as lead sulfide, carbonate, sulfate,  chromate, hydroxide, or chloride. Rolfe and
Reinbold (1977) found that about 46 percent of the total lead input in  a test watershed remained  airborne.
The total input included gaseous and particulate vehicle emissions. About 5 percent of the total  lead
input to the watershed occurred with rainfall  and about 60 percent occurred with atmospheric settleable
particulates. The streamflow accounted for the majority of all of the lead discharged from the watershed
(about 7 to 8 percent of the total lead input) .
       Nickel was detected at concentrations greater than 1 ng/L in most of the stormwater samples
analyzed by Pitt and Barron (1990). Parking area runoff samples contained the greatest median
concentrations (40 ng/L), while a landscaped area runoff sample had the highest nickel concentration
observed (130fig/L).
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       Zinc was detected by Pitt and Barron (1990) at concentrations greater than 1 ng/L in all of the
stormwater runoff samples analyzed. Roof runoff samples contained the greatest median concentration
(100 ng/L) and the highest concentration observed (1580 ng/L). The EPA (1976) stated that zinc is
usually found in nature as the sulfide.  It is often associated with the sulfides of other metals, especially
lead, copper, cadmium and iron. Callahan, et al. (1979) stated that zinc in unpolluted waters is mostly  as
the hydrated divalent cation (+2) but in polluted waters complexation of zinc predominates.  Pitt and Amy
(1973) reported that zinc is mostly found as the divalent form, as a sulfide, oxide, sulfate or hydroxide.

       The polycyclic aromatic hydrocarbon (PAH) compounds found in urban runoff (most commonly
anthracene, chrysene, fluoranthene and phenanthrene) are formed by  incomplete combustion when
organic compounds are burned with insufficient oxygen. Most of the PAHs are associated with
suspended solids and humic materials, with little dissolved fractions found in natural waters. There are
some studies that have examined the carcinogenic risk associated with the ingestion of PAHs by
humans. Many animal studies have established the wide range of carcinogenicity of PAHs by skin
contact and ingestion (Varanasi 1989). The concentrations of PAHs needed to produce cancers can be
extremely low. As an example, the  PAH concentration associated with a cancer risk level of 10"^  is only
9.7 X 10~4 ng/i_. Tissue damage and systemic toxicity has also been associated with PAH exposure
(PHS1981).

       Benzo (a) anthracene, a PAH,  was detected at concentrations  of about 2 to 60 ^g/L in 12  percent
of the stormwater samples analyzed by Pitt and Barron (1990). The greatest concentration observed was
found in an urban creek sample. A major source of benzo  (a) anthracene is gasoline, with an emission
factor as high as 0.5 mg emitted in the exhaust condensate per liter of gasoline consumed (Verschueren
1983). Wood preservative use may also contribute benzo (a)  anthracene. Typical domestic sewage
effluent values ranged from  0.2 to more than 1 |j.g/L (in heavily industrialized areas). During heavy rains,
sewage concentrations of benzo (a) anthracene increased substantially to more than 10 fig/L Benzo (a)
anthracene was reported to be both carcinogenic and mutagenic (Verschueren 1983).

       Pitt and Barron (1990) detected benzo (b) fluoranthene in concentrations greater than about 1 \i
g/L in 17 percent of the stormwater samples analyzed. The greatest concentration observed was 226 \i
g/L, found in a roof runoff sample. Benzo  (b) fluoranthene,  a PAH,  is found in gasoline,  in addition to
fresh and used motor oils (Verschueren 1983). The automobile emission factor for benzo (b)
fluoranthene is about 20 to 50 ng in the exhaust condensate per liter of gasoline consumed. It is also
found in bitumen, an ingredient of roofing  compounds. Benzo (b) fluoranthene was found in domestic
wastewater effluent in concentrations of about 0.04 to 0.2 ^g/L Raw sewage concentrations were as high
as 0.9 ng/L in areas of heavy industry.  Typical sewage concentrations were about 0.04 ng/L, but
increased to about 10 jxg/L during heavy rains. The IARC (1979) has found sufficient evidence of
carcinogenicity of benzo (b)  fluoranthene  in animals.

       Pitt and Barron (1990) detected benzo (k) fluoranthene in concentrations greater than 1 ng/L in
17 percent of all stormwater runoff samples analyzed. The  greatest concentration observed was 221 \i
g/L, found in a roof runoff sample. Benzo  (k) fluoranthene,  a PAH, is found in crude  oils, gasoline, and
bitumen (Verschueren 1983). Sewage  sludges have been found to contain from 100 to 400 \ig/L benzo
(k) fluoranthene. Domestic sewage effluent can contain from  0.03 to 0.2 ng/L benzo (k) fluoranthene,
while sewage in heavily industrialized areas may contain concentrations as great as 0.5 ng/L. During
heavy rains, sewage concentrations of benzo (k) fluoranthene increased to more than 4
       Benzo (a) pyrene, a PAH, was detected by Pitt and Barron (1990) in concentrations greater than
about 1 jig/L in 17 percent of the stormwater samples analyzed. The greatest concentration observed
was 300 ng/L, found in a roof runoff sample. Benzo (a) pyrene can be synthesized by various bacteria
                                              39

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(including Escherichia coif) at a rate of about 20 to 60 ug per dry kg of bacterial biomass (Verschueren
1983). It is also a potential leachate of asphalt and is present in oils and gasoline. Benzo (a) pyrene is
present in domestic sewage effluents at concentrations of about 0.05 ng/L and in raw sewage sludge at
concentrations of about 400 ng/L Benzo (a) pyrene is a known carcinogen and mutagen.
        Fluoranthene, a PAH, was detected in concentrations greater than about 1 ^ig/L in 23 percent of
the stormwater samples analyzed by Pitt and  Barren (1990). The greatest concentration observed was
128 ng/L, found in an urban creek sample. Fluoranthene was the only PAH found in an EPA drinking
water survey of 1 1 0 samples in 1 977 (Ham's 1 982) . Fluoranthene is found in crude oils, gasoline, motor
oils and wood preservatives (Verschueren 1983). It is found in the exhaust condensate of gasoline
engines at a rate of about 1 mg per liter of gasoline consumed. It is found in domestic sewage effluents
in concentrations of about 0.01 to 2.5 ng/L, and in raw sewage sludge at concentrations of up to about
1200 ng/L. In one case, sewage effluent had concentrations of fluoranthene of about 0.4 (ig/L during dry
weather, but increased to about 16 (ig/L during heavy rains. Several studies have shown that
fluoranthene is a potent carcinogen which substantially increases the carcinogenic potential of other
known carcinogens (EPA 1980).

        Naphthalene, a PAH, was detected in concentrations greater than about 1 jig/L in 13 percent of
the runoff samples analyzed by Pitt and Barren (1990). The greatest concentration observed was 296 (i
g/L, found in an urban creek sample. Naphthalene is the single most abundant component of coal tar,
and is present in gasoline and insecticides (especially moth balls). Naphthalene may also originate from
natural uncontrolled combustion,  such as forest fires, along with house fires in urban areas (Howard
1989). However, vehicle emissions are probably the most significant urban source of naphthalene.
Additional major urban  naphthalene sources included detergents, solvents, and asphalt (Verschueren
1983). Carcinogenicity  and mutagenicity tests were negative for naphthalene (Howard 1989).

        Phenanthrene, a PAH, was detected in concentrations greater than about 1 (ig/L in 10 percent of
the runoff samples analyzed by Pitt and Barren (1990). The greatest concentration observed was 69 n
g/L, found in an urban creek sample. Phenanthrene is found in crude oil, gasoline, and coal tar. Its
emission factor in gasoline engine exhaust condensate is about 2.5 mg per liter of gasoline consumed.
Carcinogenicity  and mutagenicity tests were negative for phenanthrene (Verschueren 1983).

        Pyrene, a PAH, was detected  in concentrations greater than about 1 (ig/L in 19 percent of the
runoff samples analyzed by Pitt and Barren (1990). The greatest concentration observed was 102 ng/L,
found in an urban creek sample. Pyrene is found in crude oils, gasoline, motor oils, bitumen, coal tar,
and wood preservatives (Verschueren 1983). The emission factor of pyrene from gasoline engine
exhaust condensates is about 2.5 mg per liter of gasoline consumed. It was degraded in seawater by 85
percent from an initial concentration of 365 |ig/L after 12 days. Pyrene is discharged in domestic
wastewater effluents at concentrations of about 2 ng/L. In one study, dry weather raw sewage had pyrene
concentrations of about 0.2 ng/L,  while pyrene concentrations in raw sewage during a heavy rain
increased to about 16 ng/L Mutagenicity test results of pyrene were negative, but pyrene is considered a
human carcinogen (Verschueren  1983).

       Pitt and Barren (1990) detected chlordane in concentrations greater than about 0.3 ng/L in 13
percent of the stormwater samples analyzed. The greatest concentration observed was 2.2 ng/L, found in
a roof runoff sample. Chlordane is a non-systemic insecticide and its registered use has been canceled
by the EPA. The food chain concentration potential of chlordane is considered high. The  EPA has also
revoked chlordane residual tolerances in foods (Federal Register, Vol. 51 , No. 247, page 46665 Dec  24
1986).
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       Butyl benzyl phthalate (BBP), a phthalate ester, was detected in concentrations greater than
about 1 ng/L in 12 percent of the stormwater samples analyzed by Pitt and Barren (1990). The greatest
concentration observed was 128 ng/L, found in a landscaped area runoff sample. BBP is used chiefly as
a plasticizer in polyvinylchlorides (Verschueren 1983). BBP is not tightly bound to the plastic and is
readily lost and enters aqueous solutions in contact with the plastic. The typical average concentration of
BBP in natural U.S. waters is about 0.4 ng/L, but was reported to be as high as 4.1
       Bis (2-chloroethyl) ether (BCEE) was detected in concentrations greater than about 1 ng/L in 14
percent of the stormwater samples analyzed by Pitt and Barren (1990). The greatest concentration
observed was 204 ng/L, found in an urban creek sample. BCEE is used as a fumigant, and as an
ingredient in solvents, insecticides, paints, lacquers and varnishes (Verschueren 1983). It is also formed
by the chlorination of waters that contain ethers.

       Bis (2-chloroisopropyl) ether (BCIE) was detected by Pitt and Barron (1990) in stormwater at
concentrations greater than about 1 ng/L in 14 percent of the samples analyzed. The greatest
concentration observed was 217 ng/L, found in a parking area runoff sample.  BCIE was not found to be
carcinogenic during rat tests (HEW 1979).

       1 ,3-Dichlorobenzene (1 ,3-DCB) was detected in concentrations greater than about 1 jig/L in 23
percent of the stormwater samples analyzed by Pitt and Barron (1990). The greatest concentration
observed was 120 ng/L, found in an urban creek sample.
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                                         SECTION 3

      POTENTIAL GROUNDWATER CONTAMINATION ASSOCIATED WITH URBAN RUNOFF


       This report section addresses several categories of constituents that are known to affect
groundwater quality, or the operation of infiltration or recharge devices, as documented in the
groundwater contamination literature. The categories that can adversely affect groundwater quality
include nutrients, pesticides, other organics, pathogens, metals, and salts and other dissolved minerals.
Suspended solids, dissolved oxygen, and the sodium adsorption ratio (the ratio of monovalent, Na+, to
divalent cations, Ca++ and Mg++) are also important for the operation of recharge and infiltration
devices.  The intention of this report section is to identify known stormwater contaminants as to their
potential to contaminant groundwater. Many of the references describe problems with these classes of
pollutants from sanitary sewage and agricultural sources, not specifically from stormwater sources.
Therefore, care must be taken when assuming that similar problems would  occur with stormwater
sources. Major differences between stormwater and these other sources which may  affect groundwater
contamination likely include the rate of pollutant application, intermittent versus continuous applications,
and the presence of interfering compounds. However, the information included in this section enables the
recognition of pollutants which should be considered when investigating stormwater infiltration. The
following section reviews the characteristics of stormwater, especially for these constituents of most
concern in groundwater contamination investigations.


GROUNDWATER CONTAMINATION ASSOCIATED WITH NUTRIENTS

Definition

       Primary nutrients are defined as "compounds or constituents that contain nitrogen (N),
phosphorus (P) and other elements that are essential for plant growth" (Hampson 1986). Other needed
aspects of nutrient use include the organic matter and bacteria that are needed to convert the primary
nutrient from its natural form to a form that the organism can use. Nitrogen-containing compounds of
interest are primarily from fertilizers and sanitary sewage, with the available nitrogen forms being nitrate,
nitrite, ammonium, and urea.  The phosphorus containing compounds of interest are generally found in
fertilizers, with the available phosphorus form being orthophosphate.  Nitrogen and phosphorus are cyclic
elements in that the combined forms may be changed and metabolized by decomposition and synthesis
(Reichenbaugh 1977).

Examples of Nutrients Contaminating Groundwaters

       Nutrients can originate from many different sources, including natural occurrence, sanitary
sewage discharges and combined sewage overflows, landscaping/lawn maintenance and other urban
sources (including septic tank and sewer  system leakage, waste decomposition, and highway runoff) plus
agricultural sources.  Nitrates are one of the most frequently encountered contaminants in groundwater
(AWWA1990).
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       Phosphorus compounds of interest are associated with phosphorus containing fertilizers (Lauer
1988a and 1988b) and detergents. Groundwater contamination by phosphorus has not been as
widespread, or as severe, as for nitrogen compounds. Nitrogen loadings are usually much greater than
phosphorus loadings, especially from nonagricultural sources (Hampson 1986).  Spray-irrigation with
secondary-treated sanitary wastewater was found to increase both the total nitrogen and nitrate
concentrations in a shallow aquifer in Florida, but these, and the total phosphorus concentrations, were
significantly  reduced within 200 feet of the test site (Brown 1982).

Natural Sources-
       Nitrogen occurs naturally both in the atmosphere and in the earth's soils. Natural nitrogen can
lead to groundwater contamination by nitrates. As an example, in regions with relatively unweathered
sedimentary deposits or loess beneath the root zone, residual exchangeable ammonium in the soil can
be readily oxidized to nitrate if exposed to the correct conditions. Leaching of this naturally occurring
nitrate caused groundwater contamination (with concentrations greater than 30 ng/L) in non-populated
and non-agricultural areas of Montana and North Dakota (Power and Schepers 1989).

       Forms of nitrogen from precipitation may be either nitrate or ammonium. Atmospheric nitrate
results from combustion, with the highest ambient air concentrations being downwind of power plants,
major industrial areas, and major automobile activity.  Atmospheric ammonium results from volatilization
of ammonia from soils, fertilizers, animal wastes and vegetation (Power and Schepers 1989).

Urban Areas-
       Roadway runoff has been documented as the major source of groundwater nitrogen
contamination in urban areas of Florida (Hampson 1986; Schiffer 1989; and German 1989). This occurs
from both vehicular exhaust onto road surfaces and onto adjacent soils, and from roadside fertilization of
landscaped areas.  Roadway runoff  also contains phosphorus from motor oil use and from other nutrient
sources,  such as bird droppings and animal remains, that has contaminated groundwaters (Schiffer
1989). Nitrate has leached from fertilizers and affected groundwaters under various turf grasses in urban
areas, including at golf courses, parks and home lawns (Petrovic 1990; Ku and Simmons 1986;  and
Robinson and Snyder 1991).

       Leakage from sanitary sewers and septic tanks in urban areas can contribute significantly to
nitrate-nitrogen contamination of the soil and  groundwater (Power and Schepers 1989).  Nitrate
contamination of groundwater from sanitary sewage and sludge disposal has been documented  in New
York (Ku and Simmons 1986; and Smith and Myott 1975), California (Schmidt and Sherman 1987),
Narbonne, France (Razack, et al. 1988), Florida (Waller, et al. 1987) and Delaware (Ritter, et al. 1989).

       Elevated groundwater nitrate concentrations have been found in the heavily industrialized areas
of Birmingham, UK, due to industrial area stormwater infiltration (Lloyd, et al. 1988).  The deep-well
injection of organonitrile and nitrate containing industrial wastes in Florida has also increased the
groundwater nitrate concentration in parts of the Floridan aquifer (Ehrlich, et al. 1979a and 1979b).

Agriculture Operations-
       In the United States, the areas with the greatest nitrate contamination of groundwater include
heavily-populated states with large dairy and  poultry industries, or states having extensive agricultural
irrigation. Extensively irrigated areas of the United States include the corn-growing areas  of Delaware,
Pennsylvania and Maryland; the vegetable growing areas of New York and the Northeast;  the potato
growing areas of New Jersey; the tobacco, soybean and corn growing areas of Virginia, Delaware and
Maryland (Ritter, et al. 1989); the chicken, com and soybean production areas in New York (Ritter, et al.
1991); the western Corn Belt states (Power and Schepers 1989); and the citrus, potato and grape
vineyard areas in California (Schmidt and Sherman 1987). Table 21 groups the states according to the
percentage of wells in the state which have groundwater nitrate concentrations greater than 3.0  mg/L.
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 TABLE 21.  GROUNDWATER NITRATE CONTAMINATION IN THE UNITED STATES
       Contaminated Well Percentage - Between 0.0 and 10.0%
       Alabama (7.4%)              Alaska (5.2%)
       Florida (4.3%)                Georgia (4.8%)
       Hawaii (9.1%)                Louisiana (2.4%)
       Massachusetts (5.5%)         Michigan (3.9%)
       Mississippi (1.8%)            Missouri (8.7%)
       Nevada (8.4%)               New Hampshire (4.3%)
       North Carolina (5.9%)         North Dakota (9.0%)
       Ohio  (8.5%)               Oregon (6.6%)
       South Carolina (4.1%)         Tennessee (5.5%)
       Vermont (6.9%)              Virginia (3.9%)
       West Virginia (5.5%)

       Contaminated Well Percentage - Between 10.1 and 20.0%
       Arkansas (12.4%)             Connecticut (16.7%)
       Idaho (14.6%)                Illinois (14.0%)
       Indiana (11.1%)              Iowa (18.4%)
       Kentucky (17.2%)             Maine (14.2%)
       Montana (11.5%)             New Jersey (11.4%)
       New Mexico  (12.7%)          South Dakota (14.9%)
       Utah (10.4%)                 Wisconsin (18.9%)
       Wyoming (11.4%)

       Contaminated Well Percentage - Between 20.1 and 30.0%
       Colorado (22.9%)             Maryland (28.8%)
       Minnesota (20.2%)            Texas (23.5%)
       Washington (22.9%)

       Contaminated Well Percentage - Between 30.1 and 40.0%
       California (32.6%)            Delaware (34.6%)
       Nebraska (32.7%)            Oklahoma (35.9%)
       Pennsylvania (30.3%)         Puerto Rico (35.4%)

       Contaminated Well Percentage - Between 40.1 and 50.0%
       Arizona (49.3%)              New York (40.3%)
       Rhode Island (45.1%)

       Contaminated Well Percentage - Greater than 50.0%
       Kansas (54.2%)

Source: Power and Schepers 1989.
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        Nitrogen leaching from agricultural fertilizers to irrigation return/drainage waters and eventually
to underlying aquifers has been documented in California (Schmidt and Sherman 1987), Arizona and
New Mexico (Sabol, et al. 1987).  Groundwater nitrate contamination has increased in these areas since
the 1930s, when large-scale irrigation was instituted (Sabol, et al. 1987). Typical nitrate concentrations
in shallow vadose-zone water beneath agricultural fields in Nebraska exceed 10 mg/L (Power and
Schepers 1989; and Spalding and Kitchen 1988).  Irrigation is necessary to leach and reduce salt
accumulation in plant root zones in many agricultural areas (Power and Schepers 1989). This leaching
generally leads to increased groundwater contamination. Similar processes are likely to occur under
irrigated urban landscaped areas,  including private homes,  parks, and golf courses.

        Rates of nitrate concentration increases in groundwater in Nebraska can be from 0.4 to 1.0
mg/L/year (as nitrogen) in well-drained agricultural soils.  In areas with fine-textured soils and thick
vadose zone sediments, the increase is smaller, from 0.1 to 0.2 mg/L/year, (Spalding and Kitchen 1988).

        Leachate from waste decomposition can also contribute nitrogen-containing compounds to
groundwater. The urine of grazing animals was the source of groundwater nitrate contamination in New
Zealand (Close 1987).  Grazing cattle return to the soil between seventy-five and eighty percent of the
nitrogen, phosphorus and potassium from their food (Reichenbaugh 1977). Land spreading of animal
waste from large-scale, concentrated dairy and poultry industries in the Northeast U.S., the Great Lakes
states (Power and Schepers 1989), and Maryland (Ritter, et al. 1989) caused the nitrate contamination of
groundwater. Poorly managed feed lots can cause enhanced nitrate production from animal wastes
which in turn leach through soil during rainfalls and enter the groundwater (Power and Schepers 1989).

Nutrient Leaching and Soil Removal Processes

        Whenever nitrogen-containing compounds come into contact with soil, a potential for nitrate
leaching into groundwater exists, especially in rapid-infiltration wastewater basins, stormwater infiltration
devices, and  in agricultural areas.  Nitrate is highly soluble (>1 kg/L) and will stay in solution in the
percolation water, after leaving the root zone,  until it reaches the groundwater. Therefore, vadose-zone
sampling can be an effective tool in predicting nonpoint sources that may adversely affect groundwater
(Spalding and Kitchen 1988).

Urban Areas-
        Nitrogen containing compounds in urban stormwater runoff may be carried long distances before
infiltration into soil and subsequent contamination of groundwater, affecting South Carolina's approach to
golf course stormwater management (Robinson and Snyder 1991). The amount of nitrogen available for
leaching is directly related to the impervious cover in the watershed (Butler 1987).  Nitrogen infiltration is
controlled by soil texture and the rate and timing of water application (either through irrigation or rainfall)
(Petrovic 1990; and Boggess 1975).  Landfills, especially those that predate the RCRA Subtitle D
Regulations, often produce significant nitrogen contamination in nearby groundwater, as demonstrated in
Lee County, Florida (Boggess 1975). Studies in Broward County, Florida, found that nitrogen
contamination problems can also occur in areas with older septic tanks and sanitary sewer systems
(Waller, et al. 1987).

        Nutrient leachates usually move vertically through the soil and dilute  rapidly downgradient from
their source.  The primary factors affecting leachate movement are the layering of geologic materials,
the hydraulic gradients, and the volume of the leachate discharge. Sandy soils show less rapid dilution of
the contaminant (mixing of leachate with groundwater), compared to limestone (Waller, et al. 1987).

        Once the leachate, or the waste liquid from an industrial injection well, is in the soil/groundwater
system, decomposition by denitrification can occur, with the primary decomposition product being
elemental nitrogen (Mickey and Vecchioli 1986). As an example, deep well injection of organonitriles
and nitrates in a limestone aquifer acts like an anaerobic filter with nitrate respiring bacteria being the
                                              45

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dominant microorganism. These bacteria cause an eighty percent reduction of the waste within one
hundred meters of injection in the Floridan aquifer, near Pensacola (Ehrlich, et al. 1979b).

       Gold and Groffman (1993) reported groundwater leaching losses from residential lawns to be low
for nitrates (typically <2mg/L), when using application rates recommended for residential lawn care.

Agricultural Areas--
       Nitrogen entry, use and removal in agricultural soils is best described in terms of the nitrogen
cycle:  plant uptake, atmospheric loss (NH3 volatilization and denitrification), soil storage, runoff into
surface water and/or leaching into groundwater (Petrovic 1990). Nitrogen  leaching from soils is common
in irrigated agricultural areas. Besides supplying required moisture, irrigation is also needed to prevent
the accumulation of salts in the crops' root zone. If salt flushing occurs when there is nitrate in the root
zone, the nitrates are leached farther into the soil and potentially into the groundwater (Power and
Schepers  1989).

       Irrigated areas in the Midwest and Upper Midwest States have a greater potential to leach
nitrates to the groundwater than most other areas because: (1)  irrigation is concentrated in areas with
high soil hydraulic conductivities; (2) irrigated lands generally receive heavy applications of  nitrogen
fertilizers to increase crop yield to offset the high cost of irrigation; and (3)  irrigation accelerates the
movement of nitrates,  other soluble constituents and percolating water to the groundwater (Mossbarger
and Yost 1989). These irrigated areas also have higher water tables than non-irrigated arid areas, further
increasing the  nitrate leachate potential.

       The mass of nitrate leached to groundwater during irrigation is related to the drainage volume
(Ritter, et al. 1989).  Nitrates that are already in the soil or groundwater also travel faster during periods
of maximum recharge (when the water table  is highest) (Boggess 1975).

       Factors that influence the degree of nitrogen leaching in agriculture areas are soil type, irrigation
amounts and practices, nitrogen source and application rate, and the season of application.  Significant
leaching occurs during the cool, wet seasons.  Cool temperatures reduce denitrification and  ammonia
volatilization, and limit microbial nitrogen  immobilization and plant uptake; however, they also limit
nitrification. The combination of low evapotranspiration and high precipitation means that more water
drains out of the root zone into the vadose zone and groundwater (Petrovic 1990). Humid agricultural
areas have shown a greater potential for nutrient leaching when compared to arid environments because
of the availability of water for leaching during the cool seasons (Close 1987). Land use and soil
permeability greatly affect groundwater chemistry, and ultimately its contamination potential, as shown in
the Coastal Plains of the East Coast by Ritter,  et al. (1989) and in California by Schmidt and Sherman
(1987).

       Although no one has indicated that the potential for nitrate contamination can be prevented,
adjustments in fertilizer practices may control the rate of degradation of groundwater (Power and
Schepers  1989). Use of slow-release fertilizers is recommended in areas with significant leaching
problems, such as coastal golf courses. The slow-release fertilizers include urea formaldehyde (UF),
methylene urea, isobutylidene diurea (IBDU), and sulfur-coated urea.  The fast-release fertilizers that  are
not recommended include calcium nitrate, sodium nitrate, ammonium sulfate and urea (Horsley and
Moser 1990).

       Methods of fertilizer application also  affect groundwater contamination. Side-dressing  of
fertilizers can increase groundwater nitrate concentrations faster than fertigation, the mixing of fertilizers
with irrigation water (Ritter, et al. 1991). However, other researchers (Saffigna and Keeney  1977) found
that side-dressing can reduce leaching, if irrigation is irregular. No difference in the depth of penetration
of phosphorus  was found between applying the same amount of fertilizer in one application versus the
same amount spread over several applications (Lauer 1988a).  Frequent fallowing of the soil (leaving
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unplanted) was found to contribute to nitrate contamination below the root zone.  Cultivation (plowing or
disking), as part of the planting process, increases aeration and mixes crop residues (which are readily
available carbon sources) with soil organisms. A flush of mineralization and nitrification usually occurs
after cultivation and results in the accumulation of leachable nitrate in the soil (Power and Schepers
1989). Nitrate contamination, however, appears to be controlled more by denitrification than by
preferential flow through the soil (Steenhuis, et al. 1988).

        Controlled application of wastewater sludge is an effective fertilizer; it has not reduced crop
yields where it has been applied and it does not contaminate the groundwater to any greater extent than
chemical fertilizer applications. Sludge applications to crop lands are generally controlled by heavy
metal accumulations in the soil and plants, not by groundwater contamination of nutrients.  Like chemical
fertilizers, sludge use in amounts that provide soil with nitrogen in excess of what plants need results in
leaching.  Liquid sludges mineralize nitrogen faster than  composted sludges with the application rate and
soil type not affecting the mineralization rate (Chang 1988). The decomposition potential in the
groundwater below wastewater irrigation areas is considerable, as the decomposition is controlled by
bacteria which are already in the wastewater (Wolff 1988):

        5  C + 4 NO3 +  2 H2O ^  2 N2 + 4 HCO3 + CO2

        Decomposition of crop waste affects nitrogen leaching potential. Non-legume residues, such as
cornstalks, decompose much slower and initially immobilize inorganic nitrogen in the biomass (Power
and Schepers 1989). The ammonium cation (NH4+) tends to decompose more readily to form ammonia
in alkaline soils than in  acid soils  (White and Dornbush 1988).

General-
        During percolation through the soil, some nutrients are removed and the nutrient concentrations
affecting the groundwater are significantly reduced.  Phosphorus, in the form of soluble orthophosphate,
may be either directly precipitated or chemically adsorbed onto soil surfaces through reactions with
exposed iron, aluminum or calcium on solid soil surfaces (Crites 1985).  Phosphorus fixation is a two-
step process, sorption onto the soil solid and then conversion of the sorbed phosphorus into mineraloids
or minerals.  If the sorption sites are filled either with phosphate anions or another ion, phosphorus
sorption will be low.  The sorption of phosphorus per unit of percolation liquid decreases with each year
of recharge (White and  Dornbush 1988).

        Downward movement of phosphorus in different soils was found to be directly related to the
reactivity index measured for each soil, especially for surface-applied phosphorus fertilizer.  In
Washington, a difference in depth of penetration was noted, however, between sandy- and clayey-
textured soils, with sandy-textured soils showing the greater depth of penetration.  If the fertilizer was
surface applied, instead of sprinkler applied, and the soil was not inverted, most of the phosphorus
remained  within the top 5 to 7.5 cm of the surface (Lauer 1988b).

        If the nitrogen is not used by the plant, it will leach through the soil toward the groundwater, with
some being removed in the soil prior to its reaching the aquifer. Under certain conditions, losses of
dissolved  nitrate and nitrite could  be described by zero-order kinetics (Hampson 1986). In general,
however, the process is regulated by so many limiting factors that such a simplified description is not
possible (Follet 1989).  Residual nitrate concentrations were found to be highly variable in soil due to
factors such as soil texture, mineralization, rainfall, irrigation, organic matter content, crop yield, nitrogen
fertilizer/sludge rate, denitrification, and soil compaction  (Ferguson, et al. 1990).  However, on sludge
application plots, it was noted that if the soil receives the same annual amount of organic residue,  it will
accumulate organic  nitrogen until the equilibrium concentration is reached. As shown in Riverside,
California, once the  sludge application is terminated, the organic nitrogen will continue to mineralize for
many years and crop yields will continue to be enhanced (Chang, et al. 1988). The amount of ammonia
                                               47

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 volatilization is influenced by the position of the nitrogen in the soil/turf grass after application. This
 position is highly influenced by rainfall and/or irrigation (Bowman, et al. 1987, as reported by Petrovic
 1990).

        Nitrate concentrations in the vadose zone of an agricultural field generally are highest near the
 surface, although during irrigation and in times of winter recharge, nitrate can be leached below the zone
 where it will be taken up by crops or denitrified.  In such cases, nitrate will eventually reach groundwater
 if excess water is added to overlying soil. As nitrogen passes through the soil, NH4+ is removed by
 cation exchange between the NH4+ and the  H+ on the soil (Ragone 1977).  Nitrogen is also removed by
 the soil aquifer treatment process through denitrification, a biological process that needs anaerobic
 conditions and organic carbon for food for the denitrifying  bacteria, which in turn produce free nitrogen
 gas and nitrous oxides (Bouwer 1985).

        Phosphorus concentrations generally decrease with depth in agricultural soils because
 phosphorus is adsorbed to soil minerals and also precipitates readily with calcium, iron, or aluminum
 (Lauer 1988b and Ragone 1977). The dominant precipitation reactions are pH dependent, forming
 mostly iron and aluminum phosphates in acid soils and calcium phosphates under alkaline conditions. In
 neutral soils, the precipitation reactions are strongly rate-limited,  so that the apparent solubility of the
 phosphate compounds is higher than under either acid or alkaline conditions ( Bouwer 1985).

 Health Problems

        Excessive nutrient concentrations can cause both environmental and human health problems.

 Environmental Problems--
        Nitrogen and phosphorus are fertilizers in aquatic  environments, just as they are on land.  The
 continual fertilization of the aquatic environment increases production of less desirable species and
 alters the  aquatic community structure (Nightingale and Bianchi 1977a).  Excess agricultural nitrogen
 applications can reduce both yields and  quality of cotton, tomatoes, sugar beets, sugar cane, potatoes,
 citrus,  avocados, peaches, apricots, apples, and grapes (Bouwer 1987).  Nitrate ingestion by livestock
 has been  linked to health problems, although livestock can tolerate up to ten times the maximum
 permissible concentrations allowed for humans with no significant adverse effects (Mossbarger and Yost
 1989).

       Excess agricultural phosphorus may  reduce crop yields because the excess phosphorus reduces
 the availability to the plants of some micronutrients, such as copper, iron, and zinc. Excess soil
 phosphorus also increases calcium precipitation (Bouwer 1987).

 Human Health Problems-
       Excess nitrate concentrations in water (>10 mg/L as N) consumed by infants causes
 methemoglobinemia, or "blue-baby disease". In infants, nitrate is converted to nitrite which binds to red
 blood cells at the oxygen binding sites and asphyxiates the child  by causing insufficient oxygen
 adsorption (Crites 1985). Nitrates may also increase the risk of stomach cancer through nitrate  reduction
 to nitrite in the mouth or stomach. The nitrites then react with the amines to form carcinogenic
 nitrosamines (Bouwer 1989).


 GROUNDWATER CONTAMINATION ASSOCIATED WITH PESTICIDES

 Definition

       Pesticides are generally classified into one of the following three groups, depending on their
targets: herbicides, fungicides, or insecticides.  Table 22 lists pesticides of potential concern in
                                              48

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groundwater contamination studies and their typical uses from Environment Canada/Agriculture Canada
(1987) and Pierce and Wong (1988).


Examples of Pesticide Contamination of Groundwaters

Urban Areas-
        Pesticides have also been used in urban areas, primarily for weed and insect control in houses,
along roadsides, in parks, on golf courses, and on private lawns (Racke and Leslie 1993).  The pesticide
loading in runoff water has been correlated to the amount of impervious cover and to the distance the
runoff will travel prior to infiltration or decomposition, as demonstrated by Lager (1977) and confirmed in
Austin, Texas by Butler, et al. (1987). Urban pesticide contamination of groundwater in central Florida
likely results from municipal  and homeowner use of these chemicals for pest control and their
subsequent collection in stormwater runoff.  Samples from the upper part of the Floridan aquifer have
contained detectable amounts of diazinon, malathion, 2,4-D,  ethion, methyl trithion, silvex ,and 2,4,5-T
(German 1989).  In California, chlordane groundwater contamination has been traced to its application
adjacent to residential foundations where it had been used for termite and ant control (Greene 1992).
Atrazine and simazine groundwater contamination was related to their use to control weeds along
roadways (Domagalski, et al. 1992). In Arizona, diazinon, dacthal, and dioxathion were detected in
stormwater runoff entering urban dry wells that recharge the aquifer (Wilson, et al. 1990).  Diazinon (at
30 jig/L) and methyl parathion (at 10 ng/L) were detected in groundwater below municipal waste
treatment plants in Florida which used land spreading or well injection of wastes (Pruitt, et al. 1985).
Gold and Groffman (1993) reported groundwater leaching losses from residential lawns to be low for
dicamba and 2,4-D (<1|u.g/L), when using  application rates  recommended for residential lawn care.

        In contrast, groundwater below Fresno, California, stormwater recharge basins only contained
one  of the organophosphorus pesticides, diazinon.  None of the ten chlorinated pesticides (aldrin,
chlordane, endosulfan I, endosulfan II, endosulfan sulfate,  DDD-mixed isomers, DDT-mixed isomers,
DDE-mixed isomers, gamma-BHC, and methoxychlor) and none of the chlorophenoxy herbicides were
found (Nightingale 1987b; and Salo, etal. 1986).

Agricultural Operations-
        Groundwater contamination by agricultural  use of pesticides has been documented in the United
States and Canada. There have been numerous observations  of pesticide contamination of
groundwater, including: alachlor (Wisconsin), aldicarb (Wisconsin, Arkansas, and California), atrazine
(Wisconsin), bromacil (South Carolina, Georgia, and Florida), DBCP (California and South Carolina),
EDB (South Carolina, Georgia, and Florida), and metolachlor (Wisconsin) (Krawchuk and Webster
1987). San Joaquin Valley (California) groundwater has been contaminated by atrazine, bromacil,  2, 4-
DP, diazinon, DBCP, 1,2-dibromoethane, dicamba, 1,2-dichloropropane, diuron, prometon, prometryn,
propazine, and simazine. Atrazine and simazine were detected in 37.5% of the shallow wells sampled
(Domagalski and Dubrovsky 1992).  In Bakersfield, California, EDB has been found in wells in
concentrations of 4 ng/L, or less (Schmidt and Sherman 1987).Sandy soils in the Coastal Plains states in
the East and Southeast are also very susceptible to pesticide leaching, primarily because the aquifer is
directly below the recharge areas (Ritter, et al. 1989). However, tile drain water samples in the
southeastern desert valleys of California showed minimal pesticide residue (Schmidt and Sherman
1987).

       The EPA has conducted extensive surveys to investigate the potential contamination of drinking
water wells by agricultural pesticides (EPA 1990). 46 pesticides have been found in groundwater of 35
states. California had 31 pesticides detected, Illinois had 17, Minnesota and New York each had 14
pesticides detected, Wisconsin had 13 detected, and Iowa had  11 detected. Natarajan and Rajagopal
                                              49

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Herbicides

Alachlor

Atrazine

Bromoxynil


2,4-D


Difenzoquat

Diclofop-methyl


Glyphosate

MCPA


Metolachlor

Triallate


Trifluralin
TABLE 22. PESTICIDES OF POTENTIAL CONCERN IN
    GROUNDWATER CONTAMINATION STUDIES

        Major Commercial Use

        Weed control in beans, corn, potatoes and soybeans

        Grassy weed control in com; soil sterilant on non-crop land

        Weed control in barley, canary seed, corn, flax, oats and seed-
        producing grasses

        Weed control in field crops and on non-crop land; soil sterilant;
        aquatic weed control (restricted use)

        Post-emergent wild oat control in barley, canary grass and wheat

        Annual grass control in alfalfa, barley, soybeans, vegetable, wheat,
        flax and canola

        Non-selective weed control in field crops, non-crop land and turf

        Weed control in alfalfa, barley, corn, flax, oats, rye, wheat and
        pastures

        Weed control in corn, soybeans and potatoes

        Pre-emergent wild oat control in barley, flax, mustard, peas, canola,
        sugar beets and wheat

        Pre-emergent weed control in field crops, vegetables and
        ornamentals
Insecticides

Carbaryl


Carbofuran



Chlorpyrifos


Diazinon
        Major Commercial Use

        Specific insect control in livestock buildings, field crops and fruits and
        vegetables

        Specific root worm, maggot, beetle and leaf hopper control in
        vegetables; grasshopper, alfalfa weevil and other insect control in
        field crops (restricted product)

        Specific insect control in field crops, vegetables and fruits; seed
        treatment for corn, beans and peas; mosquito control

        Specific insect control on fruits, vegetables, turf and non-crop land;
        insect control in livestock buildings; seed treatment
                                                                               (continued)
                                              50

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                                   TABLE 22. (CONTINUED)
Fenitrothion


Fonofos

Lindane

Malathion

Phorate

Terbufos
Specific insect control on fruits, vegetables, turf and non-crop land;
insect control in livestock buildings; seed treatment

Specific insect control in corn, onions, potatoes and tobacco

Insect control on livestock, lawns, certain grains; seed treatment

Specific insect control on livestock and in certain field crops

Specific insect control on beans, corn, lettuce and potatoes

Specific worm control in corn and sugar beets;  flea beetle control in
mustard and canola
Fungicides

Captan


Chlorothalonil


Mancozeb


Maneb


Metiram


Thiram
Major Commercial Use

Specific fungal disease control on potato seed pieces, flower, fruit,
vegetables, turf and tobacco

Fungal disease control on vegetables, potatoes, tomatoes, turf and
conifers

Specific fungal disease control on various fruits, vegetables and corn
and potato seeds

Specific fungal disease control on certain fruits and vegetables; seed
treatment for barley, flax, oats, rye, sugar beets and wheat

Specific fungal disease control on potato seed pieces; seed
treatment for barley, flax, oats and wheat

Specific fungal disease control in turf; seed treatment for vegetables,
mustard, canola, barley, wheat, rye, oats, flax, corn, soybeans,
alfalfa and fruits
Adapted from Environment Canada/Agriculture Canada (1987) and Pierce and Wong (1988).
                                              51

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(1993) summarized Iowa DNR studies that concluded that hydrology, pesticide chemistry, and time of
sampling all affected the observed occurrence of agricultural pesticides in public drinking ground water
supplies. One or more pesticides were detected in less than 10 percent of the 865 public drinking water
supply wells tested by Iowa DNR (Iowa DNR 1988 and 1990). Atrazine occurred most often and was
found in concentrations as high as 21  ng/L. Almost all atrazine was found in concentrations at less than 1
ng/L. Infiltration of soluble pesticides through the soil column was found to be the major route of
pesticides to Iowa's shallow ground water, even though the entry of surface runoff through fractures was
responsible for relatively high doses of some pesticides.

Pesticide Removal Processes in Soil

       Heavy repetitive use of mobile pesticides, such as EDB,  on irrigated and sandy soils likely
contaminates groundwater. Fungicides and nematocides must be mobile in order to reach the target
pest and hence, they generally have the highest contamination potential. Pesticide leaching depends on
patterns of use, soil texture, total organic carbon content of the soil, pesticide persistence, and depth to
the water table (Shirmohammadi and Knisel 1989). A pesticide leaches to groundwater when its
residence time in the soil is less than the time required to remove it, or transform  it to an innocuous form
by chemical or biological processes. The residence time is controlled by two factors: water applied and
chemical adsorption to stationary solid surfaces.  Volatilization losses of soil-applied pesticides can be a
significant removal mechanism for compounds having large Henry's constants (Kn), such as DBCP or
EPTC  (Jury, et al. 1983). However, for mobile compounds having low Kn values, such as atrazine,
metolachlor, or alachlor, it is a negligible loss pathway compared to the leaching  mechanism (Alhajjar, et
al. 1990).

Mobility of Pesticides--
       Estimates of pesticide mobility can be made based on the three removal mechanisms affecting
organic compounds (volatilization,  sorption, and solubility), as shown on Tables 23 through 25
(Armstrong and Llena 1992). Application  methods and formulation state can also play a significant role in
pesticide mobility. The type of pesticide formulation will affect their loss, with wettable powders exhibiting
the greatest losses to the soil (Domagalski, et al. 1992). Residues of foliar-applied water soluble
pesticides appear in high concentrations in runoff (Pierce and Wong 1988).  Pesticide movement can be
retarded or enhanced depending upon the soil conditions (Alhajjar, et al. 1990). Leaching  is enhanced in
alluvial soils (Domagalski, et al. 1992), but if the vadose zone contains restricting  layers, pesticide
movement will be slower (Sabol, et al. 1987).  Leaching is also enhanced by flood-irrigation, in areas
needing high recharge rates, and in areas with preferential flow.  The greatest pesticide mobility occurs
in areas with coarse-grained or sandy soils without a hardpan layer, having low clay and organic matter
content and high permeability  (Domagalski, et al. 1992). Structural voids, which are generally found  in
the surface layer of finer-textured soils rich in clay, can transmit pesticides rapidly when the voids are
filled with water and the adsorbing  surfaces of the soil matrix are  bypassed. This  preferential (bypass)
flow is  demonstrated in areas where the observed mobility of the pesticide in the soil is greater than the
predicted value. This flow occurs in structured, coarse grained soils, or soils with  cracks, root holes, or
worm holes. It generally does not occur on continuously flooded loam soil.  It likely results from
unsaturated flow processes and is  controlled by the mobile and immobile fractions, soil heterogeneity,
and soil spatial variability.  Preferential flow allows the pesticide to flow easily  through the  soil and
bypass the area with the greatest microbial activity and degradation (Rice, et al. 1991; and Steenhuis et
al. 1988).

       Pesticide transport past the root zone through the unsaturated zone depends on the lipophilic
nature  and other chemical characteristics of the  compound, on how the compound is used in relation to
climate and irrigation practices, and on the properties of the soil and aquifer media, including hydraulic
conductivity and total organic carbon (Domagalski, et al. 1992). Basic (high pH) pesticides, such as
atrazine, become more mobile in soils having high pH values.  Acidic pesticides ionize, depending on
                                              52

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                           TABLE 23. MOBILITY CLASS DEFINITION


Class	KfdL
1 - Mobile
II - Intermediate
mobility
III - Low mobility
IV - Very low
<0.1 to 1.0
1.0 to 10.0
10.0 to 100.0
>100.0
0.1 to 1.0
0.01 to 0.1
0.001 to 0.01
<0.001
       mobility


       Where K(d) is the soil adsorption coefficient
              M(l) is the mobility index (ratio of pollutant's migration velocity to migration velocity of
              water under saturated flow).

Source: Armstrong and LJena 1992.
                                              53

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             TABLE 24. ORGANIC COMPOUND MOBILITY FOR SANDY LOAM SOILS
Mobile (Class I)
       Organic Carbon = 0.01%
              Dicamba
              Dacthal
              2,4-D
              Diazinon
              Alachlor
       Organic Carbon = 0.1%
              Dicamba
              2,4-D
              Alachlor
              Cyanazine
       Organic Carbon = 1.0%
              Dicamba
              Diazinon
              Dacthal

Intermediate Mobility (Class II)
       Organic Carbon = 0.01%
              2,4'-Dichlorobiphenyl
              Fluorene
              Phenanthrene
              2,4,4'-Trichlorobiphenyl
              Pyrene
              Methoxychlor
              2,3',4',5-Tetrachlorobiphenyl

       Organic Carbon = 0.1%
              Malathion
              2,4'-Dichlorobiphenyl
              Fluorene

       Organic Carbon = 1.0%
              Atrazine
              Metolachlor
Cyanazine
Metolachlor
Malathion
Atrazine
Acenaphthylene

Dacthal
Diazinon
Atrazine
Metolachlor

2,4-D
Alachlor
Pentachlorophenol
Anthracene
Chlordane
Fluoranthene
Benzo(a) anthracene
Bis(2-ethylhexyl) phthalate
2,3,3',4',6-Pentachlorobiphenyl
Acenaphthylene
Pentachlorophenol
Cyanazine
                                                                              (continued)
                                             54

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                                   TABLE 24.  (CONTINUED)
Low Mobility (Class III)
        Organic Carbon = 0.01%
               Chrysene
               Benzo(a) pyrene
               Benzo(b) fluoranthene
               2,21,3,4,41,5,5'-heptachlorobiphenyl
        Organic Carbon = 0.1%
               Anthracene
               Chlordane
               Fluoranthene
               Benzo(a) anthracene
               Bis(2-ethylhexyl) phthalate
               2,3,3',4',6-Pentachlorobiphenyl
        Organic Carbon = 1.0%
               Malathion
               2,4'-Dichlorobiphenyl
               Fluorene

Very Low Mobility (Class IV)
        Organic Carbon = 0.01%
               lndeno(1,2,3-cd) Pyrene
        Organic Carbon = 0.1%
               2,3,3',4',6-Pentachlorobiphenyl
               Benzo(a) pyrene
               Benzo(b) fluoranthene
               2,2',3,414',515'-Heptachlorobiphenyl
               lndeno(1,2,3-cd) pyrene
        Organic Carbon = 1.0%
               Anthracene
               Chlordane
               Fluoranthene
               Benzo(a) anthracene
               Bis(2-ethylhexyl) phthalate
               2,3,3',4',6-Pentachlorobiphenyl
               Benzo(a) pyrene
               Benzo(b) fluoranthene
               2,2',3,4,4',515'- heptachlorobiphenyl
               lndeno(1,2,3-cd) pyrene

Source: Armstrong and Llena 1992.
2,2',4,4',515'-Hexachlorobiphenyl
Benzo(k) fluoranthene
Benzo(ghi) perylene
Phenanthrene
2,4,4'-Trichlorobiphenyl
Pyrene
Methoxychlor
2,3',4',5-Tetrachlorobiphenyl
Acenaphthylene
Pentachlorophenol
Chrysene
2,2'4,4',5,5'-hexachlorobiphenyl
Benzo(k) fluoranthene
Benzo(ghi) perylene
Phenanthrene
2,4,4'-Trichlorobiphenyl
Pyrene
Methoxychlor
2,3',4',5-Tetrachlorobiphenyl
Chrysene
2,2',4,4',5,5'-Hexachlorobiphenyl
Benzo(k) fluoranthene
Benzo(ghi) perylene
                                               55

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         TABLE 25.  ORGANIC COMPOUND MOBILITY CLASSES FOR SILT LOAM SOILS
Mobile (Class I)
       Organic Carbon = 0.01%
              Dicamba
              Dacthal
              2,4-D
              Diazinon
              Alachlor
              2,4'-Dichlorobiphenyl
       Organic Carbon = 0.1%
              Dicamba
              2,4-D
              Alachlor
              Cyanazine
       Organic Carbon = 1.0%
              Dicamba
              Diazinon
              Dacthal

Intermediate Mobility (Class II)
       Organic Carbon = 0.01%
              Pentachlorophenol
              Fluorene
              Phenanthrene
              2,4,4'- trichlorobiphenyl
              Pyrene
              Bis(2-ethylhexyl) phthalate
              2,3',4',5-tetrachlorobiphenyl
       Organic Carbon = Q.1%
              Malathion
              2,4'-Dichlorobiphenyl
              Fluorene
              Phenanthrene
       Organic Carbon = 1.0%
              Atrazine
              Metolachlor
Cyanazine
Metolachlor
Malathion
Atrazine
Acenaphthylene
Dacthal
Diazinon
Atrazine
Metolachlor

2,4-D
Alachlor
Methoxychlor
Anthracene
Chlordane
Fluoranthene
Benzo(a) anthracene
2,3,3',4',6-Pentachlorobiphenyl
Acenaphthylene
Pentachlorophenol
Anthracene
Cyanazine
Malathion
                                                                              (continued)
                                             56

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                                   TABLE 25.  (CONTINUED)
Low Mobility (Class III)
       Organic Carbon = 0.01%
              Chrysene
              Benzo(a) pyrene
              Benzo(b) fluoranthene
              2,2',3,414',5,5'- heptachlorobiphenyl
       Organic Carbon = 0.1%
              Chlordane
              Fluoranthene
              Benzo(a) Anthracene
              Bis(2-ethylhexyl) phthalate
              2,3,3',4',6-Pentachlorobiphenyl
       Organic Carbon = 1.0%
              Acenaphthylene
              2,4'-Dichlorobiphenyl
              Fluorene

Very Low Mobility (Class IV)
       Organic Carbon = 0.1%
              Chrysene
              Benzo(a)  pyrene
              Benzo(b) fluoranthene
              2,21,3,4,41>5,5'-Heptachlorobiphenyl
       Organic Carbon = 1.0%
              Chlordane
              Fluoranthene
              Benzo(a) anthracene
              Bis(2-ethylhexyl) phthalate
              2,3,3',4',6-Pentachlorobiphenyl
              Benzo(a) pyrene
              Benzo(b) fluoranthene
              2,2',3,4,4',5,5'-heptachlorobiphenyl
              lndeno(1,2,3-cd) pyrene

Reference: Armstrong and Llena 1992.
2,2',4,4',5,5'-Hexachlorobiphenyl
Benzo(k) fluoranthene
Benzo(ghi) perylene
lndeno(1,2,3-cd) pyrene

2,4,4'-Trichlorobiphenyl
Pyrene
Methoxychlor
2,3',4',5-Tetrachlorobiphenyl
2,2'4,4',5,5'-Hexachlorobiphenyl

Anthracene
Pentachlorophenol
Phenanthrene
2,2'4,4',5,5'-hexachlorobiphenyl
Benzo(k) fluoranthene
Benzo(ghi) perylene
lndeno(1,2,3-cd) pyrene

2,4,4'-Trichlorobiphenyl
Pyrene
Methoxychlor
2,3',4',5-Tetrachlorobiphenyl
Chrysene
2,2',4,41,5,5'-Hexachlorobiphenyl
Benzo(k) fluoranthene
Benzo(ghi) perylene
                                               57

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their dissociation constants, to form cationic and anionic species, and under neutral soil conditions (pH of
5 to 9), the anionic form predominates. Since these anions are negatively charged, they do not adsorb
onto the negatively charged clay mineral surfaces.  Similarly, acidic pesticides tend to be more mobile in
neutral soils (Pierce and Wong 1988). Pesticide movement will often slow as the depth increases in the
vadose zone, allowing more soil contact time. However, the soil still may not be able to completely
remove the pesticide from the water due to reduced biodegradation activity deeper in the soil (Bouwer
1987).

       Pesticide mobility comparisons have been performed for atrazine, metolachlor and alachlor in
the same soil type and it was found that alachlor mobility > metolachlor » atrazine (Alhajjar, et al.
1990), with faster movement generally occurring in sandy loam soils versus loam soils (Krawchuk and
Webster 1987).

       Restricted pesticide usage on coastal golf courses has been recommended by regulatory
agencies. The slower moving pesticides were recommended provided they were used in accordance
with the label's instructions. These included the fungicides Iprodione and Triadimefon, the insecticides
Isofenphos and Chlorpyrifos and the herbicide Glyphosate. Others were recommended against, even
when used in accordance with the  label's instructions. These included the fungicides Anilazine,
Benomyl, Chlorothalonil and Maneb and the herbicides Dicamba and Dacthal. No insecticides were on
the "banned list" (Horsley and Moser 1990).

Solubility and Sorbtivity of Pesticides--
       Leaching of the less water soluble  compounds is determined by the sorption ability of the
chemicals to the soil particles, especially the colloids. The sorption ability of the pesticide determines
whether it will remain in solution until it reaches the groundwater (Pierce and Wong 1988). Adsorption of
a pesticide to the soil stops its travel with the percolating water and prevents its contamination of the
groundwater (Bouwer 1987).  In general, pesticides with low water solubilities, high octanol-water
partitioning coefficients, and high carbon partitioning coefficients are less mobile. Also,  in general, basic
and nonionic water soluble pesticides are lost in greater amounts in surface runoff than acidic and
nonionic, low to moderate water soluble, pesticides with less traveling through the soil toward the
groundwater (Pierce and Wong 1988).

       Adsorption and desorption control the movement of pesticides in groundwater (Sabatini and
Austin 1988). Modeling of pesticide movement using physical non-equilibrium expressions for mass
transfer and diffusion most closely mimics  the actual movement in soil (Pierce and Wong 1988).

Decomposition of Pesticides-
       Pesticides decompose in soil and water, but the total decomposition time can range from days to
years. Decomposition and dispersion rates in the soil depend upon many factors, including pH,
temperature, light, humidity, air movement, compound volatility, soil type, persistence/half-life and
microbiological activity (Ku and Simmons 1986).

       Historically,  pesticides were thought to adsorb to the soil during recharge, with decomposition
then occurring from the sorbed sites. The decomposition rates are a function of temperature, moisture,
and organic content, with the microbiological community being stable.  Decomposition half-lives of many
pesticides have been determined.  However, literature half-lives generally apply to surface soils and do
not account for the reduced microbial activity found  deep in the vadose zone  (Bouwer 1987).

       Pesticides with a thirty-day half life can show considerable leaching. An  order of magnitude
difference in half-life results in a five to ten-fold difference in percolation loss  (Knisel and Leonard 1989).
Organophosphate pesticides are less persistent than organochlorine pesticides, but they also are not
strongly adsorbed by the sediment and are likely to leach into the vadose zone, and possibly the
groundwater (Norberg-King, et al. 1991).
                                              5S

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       As demonstrated in Central Florida and on Long Island, New York, sediment analysis in recharge
basins can show sediment with significant organic content, indicating that basin storage and recharge
may effectively remove a large percentage of the pesticides (Schiffer 1989; and Ku and Simmons 1986).
Most organophosphate and carbamate insecticides are regarded as nonpersistent, but they have been
found in older, organic soils used for vegetable production and in the surrounding drainage systems
(Norberg-King, et al. 1991). Studies of recharge basins in Nassau and Suffolk Counties on Long Island,
New York, showed that the DDT concentration in each basin correlated well with the basin's age and
showed that DDT can survive in recharge basins for many years (Seaburn and Aronson 1974).  Residues
of atrazine, triallate and trifluralin have carried over from year to year in Canadian field soils (Smith
1982, as reported by Pierce and Wong 1988).  Carbofuran has also survived for long periods in soil in
Manitoba, Canada, with resulting detection in the groundwater the following year (11.5 to 158.4 ng/L)
(Krawchuk and Webster 1987).

       Observed chlorothalonil in groundwater (10.1 to 272.6 ng/L) possibly resulted from one of three
sources:  1)  carryover  in the soil from the previous year before leaching to the groundwater (most
probable); 2) use in other fields and subsequent movement of the groundwater; and 3) movement of tile
drain water through the soil to the area in question.  The source water for removing the pesticide from
the soil in Manitoba, Canada, the following year was believed to be snow melt water that leached into the
ground in the early spring  (Krawchuck, et al. 1987).

       The following pesticides used in the San Joaquin Valley, California, have high leaching potential:
alachlor,  aldicarb, atrazine, bromacil, carbaryl, carbofuran, carboxin, chlorothalonil,  cyanazine,  2,4-D,
dalapon, DCPA,  diazinon, dicamba, 1,2-dichloropropane, dinoseb, disulfoton, diuron, methomyl,
metolachlor, metribuzin, oxamyl, simazine, tebruthiuron, and trifluralin (Domagalski, et al. 1992), with
some having already been detected in the groundwater. Controlling pesticide leaching to prevent future
groundwater contamination requires a reevaluation of current agricultural and residential practices and
implementation of the more progressive ones (Lee 1990).

Health Effects

       Some pesticides affect only those workers directly working with them, while others affect people
or animals near and/or downwind of the application site (Bouwer 1989). Pesticides have been linked to
cancer, nervous system disorders, birth defects, and other systemic disorders. DBCP has been linked to
male sterility in the manufacturer's employees and to cancer in animals (Sabol, et al. 1987).  Aldicarb
has not been found to  be carcinogenic, but it is highly toxic and causes a reversible inhibition of
cholinesterase, an enzyme necessary for nerve function (Bouwer  1987).  Methyl parathion and
carbofuran are the organic toxic agents in the Colusa Basin water in California. Studies of the aquatic
toxicity of these compounds found their toxicological effects to be additive when used in mixtures
(Norberg-King, et al. 1991). Table 26 lists the toxicological data for  many common pesticides.


GROUNDWATER CONTAMINATION ASSOCIATED WITH OTHER ORGANIC COMPOUNDS

Definition

       Organic compounds are defined as compounds that are comprised  mainly of carbon, nitrogen,
and hydrogen. The organic compounds discussed in this section are generally analyzed using GC/MSD
techniques and are divided into several categories, depending on  the analytical technique used or the
chemical class. The most common organic compounds that have  been investigated during groundwater
contamination studies are  listed in Table 27.
                                              59

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Pesticide

Aldicarb

Atrazine


Azinphos-methyl

Bromoxynil


Bromoxynil Octanoate

Carbaryl


Carbofuran


Chlorothalonil

Chlorpyrifos


2,4-D


Decamethrin

Diazinon


Dicamba

Diclofop-methyl

Difenzoquat


Disulfoton

EPTC

Fenitrothion
TABLE 26.  PESTICIDE TOXICOLOGICAL DATA

                  LD50/Species

                  0.93 mg/kg rat

                  3080 mg/kg rat
                  200- >5000 mg/kg quail/mallard

                  11-20 mg/kg rat

                  190 mg/kg rat
                  >5000 mg/kg quail/mallard

                  260 mg/kg rat

                  850 mg/kg rat
                  2290->10000mg/kg quail/mallard

                  8.2-14.1 mg/kg rat
                  0.397-46 mg/kg quail/mallard

                  > 10000 mg/kg rat

                  135-163 mg/kg rat
                  15.9-492 mg/kg quail/mallard

                  375 mg/kg rat
                  412- >5000 mg/kg quail/mallard

                  128 mg/kg rat

                  108 mg/kg rat
                  3.54-101 mg/kg quail/mallard

                  1040-29 00 mg/kg rat

                  557-580 mg/kg rat

                  470 mg/kg rat
                  >5000 mg/kg quail/mallard

                  2.6-12.5 mg/kg rat

                  1630 mg/kg rat

                  500 mg/kg rat
                  652-1662 mg/kg quail/mallard
                                                                             (continued)
                                            60

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                                  TABLE 26.  (CONTINUED)
Fonofos


Glyphosate


LJndane


Malathion


Mancozeb

MCPA

Metiram

Metolachlor

Metribuzin

Paraquat

Phorate


Propanil

Terbufos


Triallate

Trifluralin

Source: Krawchuk and
                      8-17 mg/kg rat
                      16.9-290 mg/kg quail/mallard

                      4320 mg/kg rat
                      >5000 mg/kg quail/mallard

                      76-200 mg/kg rat
                      490->2000 mg/kg quail/mallard

                      1200 mg/kg rat
                      1485-2968 mg/kg quail/mallard

                      5000 mg/kg rat

                      700 mg/kg rat

                      10000 mg/kg rat

                      2750 mg/kg rat

                      2200 mg/kg rat

                      150 mg/kg rat

                      2 mg/kg rat
                      0.62-575 mg/kg quail/mallard

                      1400 mg/kg rat

                      4.5-9.0 mg/kg rat
                      225 mg/kg quail/mallard

                      1675-2166 mg/kg rat

                      > 10000 mg/kg rat

Webster 1987; Pierce and Wong 1988.
                                             61

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                  TABLE 27. ORGANIC COMPOUNDS INVESTIGATED DURING
                         GROUNDWATER CONTAMINATION STUDIES
Volatile Organic Compounds

Benzene
Carbon Tetrachloride
Chlorodibromomethane
2-Chloroethylvinyl ether
1,2-Trans-dichloroethylene
Dichlorofluoromethane
1,2-Dichloroethane
1,2-Dichloropropane
Ethylbenzene
1,1,2,2-Tetrachloroethane
Toluene
1,1,2-Trichloroethane
Trichlorofluoromethane
Dibromochloropropane
Bromoform
Chlorobenzene
Chloroethane
Chloroform
Diclorobomomethane
1,1-Dichloroethane
1,1-Dichloroethylene
1,3-Dichloropropene
Methyl bromide
Tetrachloroethane
1,1,1-Trichloroethane
Trichloroethylene
Vinyl Chloride
Acid Extractable Organic Compounds
p-Chloro-m-cresol
2,4-Dichlorophenol
4,6-Dinitro-o-cresol
2-Nitrophenol
Pentachlorophenol
2,4,6-Trichlorophenol
2-Methylphenol
3-Methylphenol
3,4-Dimethylphenol
3,5-Dimethylphenol
2,3,5-Trimethylphenol
2,3,5,6-Tetramethylphenol
2-Chlorophenol
2,4-Dimethylphenol
2,4-Dinitrophenol
4-Nitrophenol
Phenol
2-Ethylphenol
2,6-Dimethylphenol
2,5-Dimethylphenol
2,3-Dimethylphenol
2,4,6-Trimethylphenol
2,3,6-Trimethylphenol
2-Napthol
                                                                              (continued)
                                             62

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Base-Neutral Extractables

Acenaphthene
Antracene
Benzo(a) anthracene
Benzo(g,h,i)perylene
Benzo(b)fluoranthene
Butyl benzyl phthalate
Bis(2-chloroethyl) ether
2-Chloronaphthalene
Chrysene
Di-n-butyl phthalate
1,4-Dichlorobenzene
3,3'-Dichlorobenzidene
Dimethyl phthalate
2,4-Dinitrotoluene
Bis(2-ethylhexyl) phthalate
Hexachlorobenzene
Hexachlorocyclopentadiene
lndeno(1,2,3-cd)pyrene
Naphthalene
N-nitrosodi-n-propylamine
N-nitrosodiphenylamine
Pyrene
Benzo(b)pyrene
                                   TABLE 27.  (CONTINUED)
Acenaphthylene
Benzidene
Benzo(a)pyrene
Benzo(k)fluoranthene
4-Bromophenyl phenyl ether
Bis(2-chloroethyoxy) methane
Bis(2-chloroisopropyl) ether
4-Chlorophenyl phenyl ether
Dibenzo(a,h)anthracene
1,3-Dichlorobenzene
1,2-Dichlorobenzene
Diethyl phthalate
2,6-Dinitrotoluene
Dioctylphthalate
Fluoranthene
Hexachlorobutadiene
Hexachloroethane
Isophrone
Nitrobenzene
N-nitrosodimethylamine
Phenanthrene
1,2,4-Trichlorobenzene
Butyl benzylphthalate
Source: German 1989; Troutman, et al. 1984; Wanielista, et al. 1991; and Salo, et al. 1986.
                                              63

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Examples of Organic Compounds Contaminating Groundwater

        Many organic compounds are naturally occurring, although many of concern in groundwater
contamination investigations are man-made.  Sources of organic contaminants include natural sources,
landfills, leaky sewerage systems, highway runoff, agricultural runoff, urban stormwater runoff, and other
urban and industrial sources and practices.

Natural Occurrence-
        Organic compounds occur naturally from decomposing animal wastes, leaf litter, vegetation, and
soil organisms (Reichenbaugh, et  al. 1977). Aerosols in groundwater usually are from precipitation
(Seaburn and Aronson 1974).

Urban Areas-
        Concentrations of organic compounds in urban runoff are related to land use, geographic
location and traffic volume (Hampson 1986).  These compounds result from gasoline and oil drippings,
tire residuals and vehicular exhaust material (Seaburn and Aronson 1974; Hampson 1986). The primary
source is from the use  of petroleum products, such as lubrication oils, fuels, and combustion emissions
(Schrffer 1989). The organic compounds on many street surfaces consists of: cellulose, tannins, lignins,
grease and oil, automobile exhaust hydrocarbons, carbohydrates and animal droppings (Hampson 1986).
Toluene and 2,4-dimethyl phenol are also found in urban runoff and are used in making asphalt  (German
1992).  Polynuclear aromatic hydrocarbons (PAHs) are also commonly found in urban runoff and result
from combustion processes, and include fluoranthene, pyrene, anthracene, and chrysene (German 1989;
Greene 1992).

        In Florida, organic compounds found  in runoff were attenuated in the soil, with only one  priority
pollutant being detected in the Floridan aquifer as a result of stormwater runoff. This compound was
bis(2-ethylhexyl) phthalate, which  is a plasticizer which readily leaches from plastics (German 1989). In
Pima County, Arizona,  base/neutral compounds appeared in groundwater from residential areas, while
phenols in the groundwater were noted only near a commercial site. Groundwater from a commercial
site, also in Pima County, has been contaminated with ethylbenzene and toluene.  Perched groundwater
samples from residential sites showed the presence of toluene, xylene, and phenol (Wilson, et al. 1990).
On Long Island, New York, benzene (groundwater concentrations of 2 to 3 ng/L); bis(2-ethylhexyl)
phthalate (5 to 13 fig/L); chloroform (2 to 3 ng/L); methylene chloride (stormwater concentration  of 230  \i
g/L and groundwater concentrations of 6 to 20 i^g/L); toluene (groundwater  concentrations of 3 to 5 ng/L);
1,1,1-trichloroethane (2 to  23 i^g/L); p-chloro-m-cresol (79 ng/L); 2,4-dimethyl phenol (96 ng/L); and 4-
nitrophenol (58 ng/L) were detected in groundwater beneath stormwater recharge basins (Ku and
Simmons 1986).

        Leaky sanitary sewerage in the Munich, Germany urban area has caused elevated
concentrations in groundwater of total organic carbon, chloroform, trichloroethylene, and
tetrachloroethylene (Merkel, et al.  1988). Volatile organic compounds (chloroform concentrations of 4.5
to 29 ng/L) were detected in the groundwater  below twelve of fifteen municipal wastewater treatment
plants throughout Florida (Pruitt, et al. 1985).

        Organic compounds can leach from municipal waste landfills and other disposal sites, including
unlined industrial surface impoundments and  older hazardous waste landfills.  Municipal waste landfills
are sources of phthalate compounds that leach from plastic and detergents. Bis(2-ethylhexyI)phthalate
can become airborne during municipal waste  incineration, can be leached from plastics in a landfill, and
was detected in water samples from the Floridan aquifer (German 1989). Surface impoundments used
to contain industrial wastewater at a wood treatment plant showed significant amounts of residual
pentachlorophenol (PCP),  creosote, and diesel fluids and has led to the phenolic contamination  of the
groundwater near a wood treatment facility  near Pensacoia, Florida (Troutman, et al. 1984).
                                             64

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        Industrial areas contribute heavily to the organic compound load that could potentially leach to
the groundwater. Surface impoundments may be used to contain industrial wastes, deep well injection
may be used to dispose of water, and stormwater runoff may collect organics as it passes over an
industrial site. Phenols and the PAHs benzo(a)anthracene, chrysene, anthracene and
benzo(b)fluoroanthenene, have been found in groundwater near an industrial site in Pima County,
Arizona. The phenols are primarily used as disinfectants and as wood preservatives and were present in
the stormwater runoff, although they were significantly reduced in concentration by the time they reached
the groundwater (generally less than 50 ng/L). At an Arizona recharge site, the groundwater has higher
concentrations of trichloroethylene, tetrachloroethylene, and pentachloroanisole, than the inflow water,
indicating past industrial contamination (Bouwer et al. 1984).

        Documented industrial groundwater contamination is not limited to the United States.  In
Birmingham, UK, groundwater contamination resulted from hydrocarbon oil and volatile chlorinated
solvent use.  The metals-related industries have contributed significant amounts of trichloroethylene
(groundwater concentrations of up to 4.9 mg/L have been noted) to the groundwater in this area, and
since trichloroethylene has been replaced by  1,1,1-tri-chloroethane in industry,  1,1,1-tri-chloroethane
contamination is beginning to occur. The other organic compound to show up in significant
concentrations in Birmingham is perchloroethylene,  a solvent used primarily in the laundry industry
(Lloyd, et al.  1988). On the left bank of the Danube, the petrochemical refinery Slovnaft has contributed
to groundwater contamination by leaking oil during tanker loading and unloading (Marlon and Mohler
1988).

Soil Removal Processes for Organic Compounds

        The appearance in groundwater of organic compounds, along with elevated nitrate
concentrations, has been used as an indicator of groundwater contamination (Lloyd 1988).  Most
organics are  reduced in concentration during  percolation through the soil, although they may still be
detectable in the groundwater. Groundwater  contamination from organics, like from other pollutants,
occurs readily in areas with pervious soils, such as sand and gravel, and where the water table is near
the land surface  (Troutman, et al. 1984). Based on septic tank  effluent studies, sand seems to be more
effective than limestone in filtering the organic material  (Schneider, et al. 1987). In coastal areas and
valleys, direct interaction of groundwater and  surface water will result in groundwater contamination if the
surface water is contaminated (Troutman, et al. 1984).  Organic removal from the soil and recharge
water can occur by one of three methods: volatilization, sorption, and degradation (Crites 1985; and
Nellor, et al. 1985). Estimates of organic compound  mobility can be made based on the three removal
mechanisms affecting organic compounds (volatilization, sorption, and solubility), as previously shown
on Tables 23 through 25 (Armstrong and Llena 1992).

Volatilization of Organics-
        The rate of volatilization is controlled  by the  compound's physical and chemical properties; its
concentration; the soil's sorptive characteristics; the soil-water content; air movement; temperature; and
the soil's diffusion ability.  Volatilization can occur both during application and from soil sites after
infiltration. Volatilization during application is  controlled by the compound's physical and chemical
characteristics, atmospheric conditions, and application method (Crites 1985) and  has been measured by
observing the reduction in the organic concentration across an infiltration basin.

        Volatilization from sorbed sites of soils is a function of: transfer of the organic from the soil's
sorbed sites to the solution, movement from the solution to the  air trapped in the soil and diffusion of the
compound in the soil air to the atmosphere. The extent of each of the above reactions depends on the
compound's solubility, its concentration gradient in the soil, and proximity of the molecule of interest to
the soil surface (Crites 1985).
                                               65

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        Volatile organic compounds are rarely found in stormwater recharge basins (<2.4 ng/L), drY wells
 (<175 ng/L), or the vadose zone or groundwater below the basins (<4 ng/L), as indicated by studies in
 Fresno, California, by Nightingale (1987b) and in Pima County, Arizona by Wilson, et al. (1990).

 Sorption of Organic Compounds--
        There are at least six different sorption mechanisms:  cation exchange, anion exchange, cation-
 dipole and coordination bonds, hydrogen bonding, van der Waals attraction, and hydrophobic bonding
 (Crites 1985).  Sorption is a function of the following soil-water-compound system characteristics: sorbate
 shape/configuration (including structure and position of functional groups and presence and degree of
 molecular saturation); sorbate chemical characteristics (including acidity or basicity; water solubility;
 charge distribution; polarity and polarizability); and sorbent nature (including mineralogical composition,
 organic matter content and cation exchange capacity (CEC) (Crites 1985) with the clay  and  particulate
 organic matter content controlling the sorption (Bouwer et al. 1984).

        Hydrophobic sorption onto organic matter were found to limit the mobility of less soluble
 base/neutral and acid extractable compounds through organic soils and the vadose zone in  Orlando,
 Florida (German 1989). The degree of removal in soil of nonhalogenated organic compounds is greater
 than that of the halogenated organics (Bouwer et al. 1984).  Benzene, toluene and xylene were found in
 the soils and in the perched water table in Arizona and, as these compounds are relatively soluble, they
 may percolate easily through the vadose zone. The toluene concentration in the perched-water table was
 54 ng/L, while the toluene concentration in the water table was 3.7 ng/L (Wilson, et al. 1990).
        Sorption is not always a permanent removal mechanism. A study in Florida has shown that
organic solubilization can occur for several storms following dry periods. However, extended periods of
complete aeration of bottom sediments may be counter-productive when trying to reduce organic
compound concentrations (Hampson 1986).

Degradation and Decomposition of Organic Compounds-
        The third process for organic compound attenuation is chemical or biological degradation.
Examples of chemical degradation processes include hydrolysis and photodegradation. However, most
of the trace organic removal is the result of biologic degradation (Smith and Myott 1975).  Many organics
can be degraded by microorganisms, at least partially, but others cannot.  Temperature, pH, moisture
content, cation exchange capacity, and air availability may limit the microbial degradation potential for
even the most degradable organic (Crites 1985). The end products of complete aerobic degradation
include  carbon dioxide, sulfate, nitrate, phosphate, and water, while the end products under anaerobic
conditions include carbon dioxide, nitrogen, hydrogen sulfide, and methane (EPA 1992).

        Conditions in the thick, aerobic, unsaturated zone provide a good environment for wastewater
detergent concentration reduction through biochemical degradation and adsorption (Smith and Myott
1975). Halogenated one- and two-carbon aliphatic compounds are biotransformed under methanogenic,
but not aerobic, conditions (Bouwer, et al. 1984). The rate of breakdown of chlorinated hydrocarbons in
the soil increases with temperature, water content, and organic matter content (Bouwer 1987).
Nonhalogenated hydrocarbons decreased fifty to ninety percent during percolation through the soil, with
concentrations in the renovated water being detectable, but near, or below, the detection limit. The
halogenated organic compounds generally decreased to a lesser extent during percolation.

        The chlorinated aromatics are relatively refractory and mobile in the ground and have lesser
concentration decreases than nonchlorinated aromatic hydrocarbons. Significant reductions of TOC
concentrations occurred during the first several meters of soil percolation and a gradual decrease in TOC
concentration occurred with longer underground travel times at the Phoenix 23rd Ave. recharge project
site (Bouwer, et al. 1984).
                                              66

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       Pretreatment of the recharge water in Arizona by chlorination resulted in higher chloroform
concentrations and in the formation of three brominated trihalomethanes (Bouwer, et al. 1984).  Ponds
and lakes affected by stormwater runoff have a high potential for the formation of trihalomethanes
(THMs) with chlorination because of the precursor organics existing in the stormwater. Factors which
affect THM formation include the chlorine contact time, pH, and temperature. Precursors to THM
formation in stormwater include algae, bacteria, and humic substances (Wanielista, et al. 1991).

       At an injection well site in Florida, organic carbon compounds were microbially converted to
carbon dioxide and ammonia within 100 meters of the injection well (Mickey and Vecchioli 1986).  In
general, deep well injection in Florida showed that organic compounds are being mineralized in  the
Floridan aquifer (Ehrlich, et al. 1979b).

       Anaerobic methanogenic bacteria in a surface impoundment located at a wood treatment plant
near Pensacola, Florida, reduced the total phenol concentration by forty-five percent. However, the
presence of pentachlorophenol inhibits methanogenesis, reducing the removal of some organics in the
impoundment (Troutman, et al. 1984).  In Arizona, partial degradation of the chlorinated benzenes
occurs during percolation through the aerobic zone, but the poor overall removal efficiency of chlorinated
aromatics probably results  from their lack of degradation under anoxic conditions.  In general, infiltration
and percolation through the soil has the effect of dampening concentration fluctuations and eliminating
occasional extreme values (Bouwer, et al. 1984).

Health Effects

       Some of the organics listed as hazardous to human health include: benzene, ethylenimine,
ethylene dibromide, benzidene, carbon tetrachloride, tricresyl phosphate, chloroform, allyl chloride,
aroclor 1254, and  benzolalpyrene (Crites 1985).  Disease outbreaks due to water contamination by
organics has been documented for the following compounds: cutting oil, developer fluid  (hydroquinone,
paramethylamino  phenol),  ethyl acrylate, fuel oil, leaded gasoline, mixtures of lubricating oil and
kerosene, phenol, and polychlorinated biphenyl.  In Wisconsin, an accidental phenol spill caused an
illness in the area  residents that was characterized by diarrhea, mouth sores, burning of the mouth, and
dark urine (Craun  1979). Runoff from paved areas in urban Arizona commonly was found to contain the
following four suspected carcinogenic PAHs: benzo(a)anthracene, benzo(b)fluoranthene,
dibenzo(a,h)anthracene and chrysene (Wilson, et al. 1990).


GROUNDWATER CONTAMINATION ASSOCIATED WITH PATHOGENS

Definition

       Microorganism human pathogens include viruses, protozoa, or bacteria that cause specific
human diseases.  When evaluating the potential contamination of groundwater,  all microorganisms are
important because not only do those that are harmful need to be controlled, but those that are necessary
for decomposition of other nutrients and contaminants need to be encouraged. Human enteric viruses of
concern in water are shown in Table 28.

       Microorganisms that have been studied in urban runoff (both the harmful and the
environmentally necessary ones) include: Shigella, Salmonella, Giardia lamblia,  Yersinia Enterocolitica,
E. colt, Methanogenic bacteria, Azonmonas, Acinetobacter, Pseudomonas, Bacillus, Flavobacterium,
Alcaligenes, Thiobacillus, Leptothrix, Siderocapseceae, Metallogenium, Vibrio, Campylobacter,
Leptospira, Streptococci, Beggiotoa, Micrococus, Proteus, Aeromonas, Serratia, and Gallionella.
                                              67

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                                   TABLE 28.  VIRUS TYPES

Virus Group                               Number Of Types
Enteroviruses
       Poliovirus                                   3
       Echovirus                                   34
       Coxsackie Virus A                            24
       Coxsackie Virus B                            6
       New Enteroviruses
Hepatitis Type A (probably                            1
       an enterovirus)
Rotavirus (reovirus family)                            2
       (gastroenteritis Type B)
Reovirus                                           3
Adenovirus                                         >30
Parvovirus                                          3
Adeno-Associated Virus

Source: Crites 1985.
Examples of Microorganism Contamination of Groundwater

       Pathogen sources that potentially contaminate groundwater include waste decomposition,
sanitary sewage, agriculture, urban runoff, and natural occurrence.

Natural Occurrence--
       Several types of bacteria occur naturally in water. The bacteria groups found in flowing water
include sheathed bacteria, iron-manganese bacteria and some of the sulfur oxidizing bacteria
(Wanielista, et al. 1991). Bacteria that affix to carbon and are water and soil chemoorganotrophs include
Azonmonas, Acinetobacter,  Pseudomonas, Bacillus, Flavobacterium and Alcaligenes.

       Beggiatoa are filamentous bacteria that produce polysaccharidic sheath-like slimes. They are
found at the sulfide/oxic interface of fresh or marine waters or estuaries. Gallionella is chemolithotrophic
(it oxidizes inorganic ferrous iron and assimilates carbon dioxide).  It is characterized by twisted stalks
containing the organic material to which the ferric hydrate is bound.  Leptothrix, if it is the dominant
bacteria in water, indicates a high iron and/or manganese concentration in the water. Metallogenium are
aerobic, chemoorganotroph/parasitic  organisms that are found in surface waters near anaerobic
sediments, decomposing layers of leaf litter, or bottom deposits of lakes. The Siderocapsaceae family of
bacteria are non-filamentous, aerobic/anaerobic, facultative/obligate slime-encapsulated bacteria that
precipitate iron and manganese. They occur in swamp ditches, stagnant waters, and in the hypolimnion
of lakes, and use organic carbon of iron-manganese humates.  Thiobacillus is an aerobic, non-
aggregating bacteria which oxidizes reduced sulfur into sulfate and is found in sulfur-bearing water.
Thiothrix bacteria are found  in sulfide or thiosulfide containing waters and in wastewater treatment plants
(Reichenbaugh, et al. 1977).

       The bacteria found in the aquifer at a recharge site at Bay Park, New York, included obligate
a jrobes and facultative  anaerobes such as Alcaliganes, Micrococus, Flavobacterium, Acinebacter,
Proteurs, Aeromonas, and Serratia. These bacteria used the soluble organic matter  in the recharge
                                              68

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water as food. Denitrifying strains of Pseudomonas fluorescens grow under the anaerobic conditions of
the Magothy aquifer by using nitrate as a terminal electron acceptor.  Several Pseudomonas species,
including P. fluorescens, P. aeruginosa, P. putida, P. alcaligenes, and P. pseudoalcaligenes can sustain
themselves under anaerobic conditions by decomposing arginine, an amino acid, through substrate level
phosphoration (Ehrlich, et al. 1979a).

Urban Areas--
        When comparing urban runoff on Long Island,  New York, low-density residential and
nonresidential areas contributed the fewest bacteria to the storm runoff, while medium-density residential
and commercial areas contributed the most. The amount of each bacteria species in the runoff varied by
season, with the warm seasons having significantly more fecal coliforms and fecal streptococci than the
colder seasons. However, total coliform concentrations were not affected by the season (Ku and
Simmons 1986).

        Viruses were detected in groundwater on Long Island at sites where stormwater recharge basins
were located  less than thirty-five feet above the aquifer (Vaughn, et al. 1978). At other locations, viruses
are likely removed from the percolation water by either adsorption and/or inactivation.

        Rain water infiltration through solid  wastes readily carries decomposition products, in addition to
bacteria and viruses,  downward through the soil to the  groundwater. The highest contaminant
concentrations occur when the water table is near the land surface (Boggess 1975).  Bacterial pathogens
found in human and animal feces and the resulting wastewater include Escherichia coll, Salmonella,
Shigella, Yersinia, Vibrio, Campylobacter and Leptospira (Amoros, et  al. 1989).  Leaky sanitary sewerage
systems or septic tanks may leach these bacteria into storm drainage systems or directly into
groundwater.

        Shigella is not as common in wastewater as Salmonella in developed countries, although it is
more  prevalent in the tropics and subtropics. Salmonella is the most common disease-causing bacteria
found in wastewater (Crites 1985).

Agricultural Operations--
        Agricultural uses of treated effluent in fertilization can also promote the spread of pathogens to
the soil where, during irrigation, they can pass through  the soil to the groundwater (Robinson and Snyder
1991). Bacteria also can be returned to humans through vegetables irrigated with inadequately
disinfected sewage effluent (Amoros, et al.  1989).

Soil Removal Processes for Pathogens

        During land application or burial of sewage sludge, pathogens may leach from the sludge and
contaminate groundwater, although most are removed  in the soil during percolation (Gerba  and Haas
1988).

       The factors that affect the survival of enteric bacteria and viruses in the soil include pH,
antagonism from soil  microflora, moisture content, temperature, sunlight, and organic matter. The effect
of each  of these factors is given in Table 29 (Crites 1985). In general, drying of the soil will kill both
bacteria and viruses.

Viruses-

       Viral adsorption-Viral adsorption is promoted by increasing cation concentration, decreasing pH
and decreasing soluble organics (EPA 1992) and is controlled by both the efficiency of short-term virus
retention and the long-term behavior of viruses in the soil  (Crites 1985).  The effect of each of these
                                              69

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                TABLE 29.  SOIL CHARACTERISTICS FOR PATHOGEN REMOVAL
Factor
pH
Pathogen Type
Antagonism
 from soil
 microflora

Moisture
 content
Temperature


Sunlight
Organic
 matter
Source: Crites 1985.
Bacteria



Viruses

Bacteria

Viruses

Bacteria and
 viruses
Bacteria and
 viruses

Bacteria and
viruses

Bacteria and
viruses
                                                  Remarks
Shorter survival in acid
 soils (pH = 3 to 5) than
 in alkaline and neutral
 soils.
Insufficient data.

Increased survival time
 in sterile soil.
Insufficient data.

Longer survival  in moist
 soils and during periods
 of high rainfall.

Longer survival at low
 (winter) temperatures.

Shorter survival at the
 soil surface.

Longer survival (regrowth
 of some bacteria) when
 sufficient amounts of
 organic matter are
 present.
                                             70

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factors is given in Table 30 (EPA 1992 and Crites 1985).
       The downward movement and distribution of viruses are controlled by convection and hydraulic
dispersion mechanisms. Since the movement of viruses through soil to groundwater occurs in the liquid
phase and involves water movement and associated suspended virus particles, the distribution of viruses
between the adsorbed and liquid phases determines the viral mass available for movement.

       The distribution (or sorption) of virus particles in the soil matrix is largely due to electrostatic
double layer interactions and Van der Waals forces. Adsorption of viruses in soil is rapid and reversible
and can be adequately described by an equilibrium (linear Freundlich isotherm) expression (Tim and
Mostaghim 1991). Viral adsorption by the soil does not necessarily result in virus inactivation and has
been shown to be reversible after a change in soil conditions, such as the ionic environment (Jansons, et
al. 1989b; and Vaughn, et al. 1978). Also, once the virus reaches the groundwater, it can travel laterally
through the aquifer until it is either adsorbed or inactivated (Vaughn, et al. 1978).

       Viral inactivation-Enterovirus survival in groundwater is highly variable and is influenced by a
number of factors, including: virus type, pH, temperature, dissolved oxygen concentration, and microbial
antagonism (Jansons, et al. 1989b; and Tim and Mostaghim  1991). The two most important attributes of
viruses that permit their long-term survival in the environment are their structure and very small size.
These characteristics permit virus occlusion and protection within colloid-size particles.  Viruses in
wastewater applied to the soil are integral  parts of submicron particles and are small enough to move
with the applied water to the groundwater (Wellings 1988).

       Dissolved oxygen is a significant factor in loss of virus activity in groundwater, possibly because
direct oxidation of components of the virus capsid inactivates the virus  or, as with temperature, the level
of dissolved oxygen influences the activity of antagonistic microorganisms. At temperatures below 4°C,
microorganisms can survive for months or even years, whereas at higher temperatures, inactivation or
dieoff occurs rapidly. Decreasing pH promotes virus adsorption and results in shorter survival times, both
of the virus and of the antagonistic bacteria. High levels of organic matter appear to shield viruses from
adsorption (Treweek 1985). Virus inactivation in the subsurface environment can be described by a first
order decay reaction (Tim and Mostaghim 1991).  It is difficult to describe a soil that will remove all
viruses effectively, as different soil types affect each virus differently (Jansons, et al. 1989a).

       Enteric viruses are more resistant to environmental factors than enteric bacteria and they exhibit
longer survival times in natural waters. They can occur in potable and marine waters in the absence of
fecal coliforms. Enteroviruses are more resistant to commonly used disinfectants than are indicator
bacteria, and can occur in groundwater in the absence of indicator bacteria (Marzouk, et al. 1979).

Removal of bacterial pathogens-
       The major bacterial removal mechanisms in soil are straining at the soil surface and at intergrain
contacts, sedimentation, sorption by soil particles, and inactivation  (Crites 1985).  Potable water use
requires continuous disinfection to prevent disease outbreaks in the water consumers (Craun 1979).

       Not all bacteria are harmful and need to be removed from the water. For example,
methanogenic bacteria  are responsible for the decomposition of phenolic compounds in potential
recharge water (Troutman, et al. 1984).

       Bacterial movement-The characteristics of bacterial movement through porous media, such as
an aquifer, include the following (Ehrlich, et al. 1979a):

       • Bacteria travel with the flow of water, not against the hydraulic gradient.
       • The rate of bacterial movement through filtering is a function  of the nature of the aquifer
        materials, with silt and sand having high clay contents being the best materials for bacterial
                                               71

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  TABLE 30. FACTORS THAT INFLUENCE VIRAL MOVEMENT IN SOIL AND TO GROUNDWATER
Soil Type. Fine-textured soils retain viruses more effectively than light-textured soils. Iron oxides
increase the adsorptive capacity of soils.  Muck soils are poor adsorbents. The higher the clay content
of the soil, the greater the expected removal of the virus. Sandy loam soils and other soils containing
organic matter are also favorable for virus removal. Soils with a small surface area do not achieve good
virus removal.

pH. Generally, adsorption increases when pH decreases. However, the reported trends are not clear due
to complicating factors.

Cations. Adsorption increases in the presence of cations (cations help reduce repulsive forces on both
virus and soil particles). Rain water may desorb viruses from soil due to its low conductivity.

Soluble organics.  Organics generally compete with viruses for adsorption sites. No significant
competition at concentrations found in waste water effluents. Humic and fulvic acids reduce virus
adsorption to soils.

Virus type.  Adsorption to soils varies with virus type and strain. Viruses may have different isoelectric
points.

Flow rate. The higher the flow rate, the lower virus adsorption to soils.

Saturated vs. unsaturated flow. Virus movement is less under unsaturated flow conditions.

Rainfall. Viruses retained near the soil surface may be eluted after a heavy rainfall because of the
establishment of ionic gradients within the soil column.
Sources: EPA 1992; and Crites 1985.
                                              72

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  removal.
        • The rate of bacterial removal by filtering can be characterized by the filter efficiency of the
         aquifer (filterability).
        • Typically, the maximum distance that bacteria travel in a porous media ranges from fifty to
         one hundred feet.
        • Under favorable condition, bacteria may survive as long as five years.

        Stable populations of bacteria in soil and water may become established due to an increased
concentration of adsorbed organics and due to the large surface area of the granules to which they
attach themselves (Wanielista, et al. 1991).

        Bacteria survival-Factors such as temperature, pH, metal concentration, nutrient availability and
other environmental characteristics affect the ability of a bacterial colony to survive in the water or soil
(Ku and Simmons 1986). Once the microorganisms are retained in the soil, their survival depends upon
the sunlight exposure, oxidation rates, desiccation and antagonism from the established soil microbial
population (Crites 1985).

        Bacteria survive longer in acid soils and when large amounts of organic matter are present.
Bacteria and larger organisms in wastewater are usually removed during percolation through a short
distance of soil (EPA 1992). When recharging using deep well injection, the logarithm of the coliform
bacteria density decreases linearly with distance from the recharge well (Ehrlich 1979).

        In general, enteric bacteria survive in soil between two and three months, although survival
times up to five years have been documented (Crites 1985).  E. colican survive and multiply on trapped
organic matter and Salmonella and Shigella have survived for forty-four days and twenty-four days,
respectively, at a recharge site in Israel (Goldschmid 1974).

        Significant dieoff can be achieved using intermittent rapid infiltration of wastewater and allowing
the recharge basin to dry out (Crites 1985). When the recharge is stopped,  the bacteria multiply, using
the accumulated organic debris for food.  The decomposition of the organic  matter starts as an aerobic
process. After the oxygen has been consumed, the process turns anaerobic and septic. At this stage,
some denitrification and sulfate reduction takes place and the decomposition of the organic matter will
lead to a partial reduction in clogging. Pathogenic enterobacteria are unable to multiply under these
conditions, but they can survive for a relatively long time. About a hundred  days after recharge, the
decomposition process ended and no more coliform bacteria were found in the pumped water from the
recharged aquifer in Israel (Goldschmid 1974).

Health Effects

        Human health can be affected through waterborne diseases transmitted by bacteria, viruses,
protozoa, and parasites (Crites 1985). Many microorganism caused diseases may be spread by person-
to-person contact, or through contact of infected  material (Gerba and Goyal 1988). Health effect
research now goes beyond the acute effect of pathogens to the chronic problems associated with
carcinogens and mutagens, and the other problems caused by long-term ingestion of low concentrations
of these organisms (DeBoer 1983).

       The development of clinical illness depends on numerous factors, including the immune status of
the host, the age of the host, virulence of the microorganisms, type and strain of the microorganisms,
and the route of infection. Mortality rates are affected  by many of the same factors that determine the
development of clinical illness (Gerba and Haas 1988).

Viruses-
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       Enteric viruses can survive typical sewage treatment processes, including chlorination, in
sufficient numbers to be detectable in the discharged water.  Peak concentrations of these viruses occur
in the late summer and early autumn.  The documented outbreaks of viral diseases from groundwater
contamination have been limited primarily to infectious hepatitis (Crites 1985; Craun 1979).
       Human enteric viruses of concern, and their diseases or symptoms, are given in Table 31.
Virus Group

Poliovirus
Echovirus
Coxsackie Virus A
Coxsackie Virus B

New Enteroviruses

Hepatitis Type A
Rotavirus
Reovirus
Adenovirus
Parvovirus

Adeno-associated
 virus
Norwalk virus
Astrovirus
Renovirus
   TABLE 31.  ENTEROVIRUSES AND DISEASES

Disease Or Symptom

Paralysis,  meningitis, fever, encephalitis, gastroenteritis
Meningitis, respiratory diseases, rash, diarrhea, fever
Herpangina, respiratory disease, fever meningitis, myocarditis, diabetes
Myocarditis,  congenital heart anomalies, rash, fever, meningitis, respiratory
        disease, pleurodynia, encephalitis
Meningitis, encephalitis, respiratory disease, acute hemorrhagic
        conjunctivitis, fever,  gastroenteritis
Infectious  hepatitis
Epidemic vomiting and diarrhea, chiefly in children, gastroenteritis
Respiratory infections
Respiratory disease, eye infections, conjunctivitis, gastroenteritis
Associated with respiratory diseases in children, but etiology not clearly
        established
Associated with respiratory diseases in children, but etiology not clearly
        established
Vomiting, diarrhea, fever, acute gastrointestinal disease
Gastroenteritis
Not clearly established
Sources: Crites 1985; Tim and Mostaghim 1991.
Bacteria-
       Shigella and Shiga bacillus are dysentery bacilli and cause mild to acute diarrhea, abdominal
pains and blood in the stool. Acute gastroenteritis and typhoid fever result from the Salmonella bacteria.
Symptoms of Salmonella contamination include abdominal cramps, nausea, vomiting and diarrhea
(Craun 1979).  Most outbreaks of salmonellosis can be traced to transmission of the bacteria via food,
milk or direct contact, but its contamination of water supplies, with a resulting disease outbreak, occurred
as recently as 1963. The bacteria Escherichia coli are responsible for some of the diarrhea diseases, just
like Shigella and Salmonella (Crites 1985). Azomonas, Acinetobacter, Pseudomonas bacillus and
Flavobacterium do not pose an immediate threat to human health, but they are opportunistic pathogens,
chlorine resistant and/or suppressors of total coliform (Wanielista, et al. 1991).

       Reviews of past disease outbreaks due to water contamination has shown that acute
gastrointestinal illnesses were slightly higher in  groundwater systems, compared to surface water
systems, due to the lack of treatment, or the use of poor treatment practices.  For surface water systems,
contamination and the resulting outbreaks were caused by contaminated ice or containers,
backsiphonage, cross-connections, water main breaks, or accidental contamination of treated storage
reservoirs (Craun 1979).
                                              74

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GROUNDWATER CONTAMINATION ASSOCIATED WITH METALS

       Even in small concentrations, metals may be a problem when infiltrating stormwater, especially
when using a rapid infiltration system (Crites 1985).  The heavy metals of most concern include lead,
copper, nickel, chromium, and zinc.  However, most of these metals have very low solubilities at the pHs
found in most natural waters and they are readily removed by either sedimentation or sorption removal
processes (Hampson 1986). Many are also filtered, or otherwise sorbed, in the surface layers of soils in
infiltrating devices using surface infiltration.

Examples of Metals Contaminating Groundwater

Urban Areas-
       Nickel, chromium, and zinc concentrations exceeded the regulatory limits in the soil below a
recharge area at an Arizona commercial site. However, only manganese was present at an elevated
concentration in the groundwater at a residential site (Wilson, et al. 1990).

       At a site in  Lee County,  Florida, groundwater near an unlined landfill had elevated iron
concentrations due to landfill leachate. The leachate also may have increased the groundwater
manganese concentrations (Boggess 1975). In New York, cesspool leachates have elevated the
concentrations of boron and barium in the shallow groundwaters of the Magothy Aquifer (Smith and
Myott1975).

       Boron concentrations were found to be high in groundwaters below industrialized areas in
Birmingham, UK, as it is used in many metal-related industries. The presence of high concentrations of
aluminum, cadmium, manganese, and titanium was also noted in the groundwaters near metals
industries in the Birmingham industrial area (Lloyd, et al. 1988).

Agricultural Operations-
       In the Tulare Lake region of the Central Valley of California, the metals that have adversely
affected groundwater quality include: boron, cadmium, chromium, copper, molybdenum, nickel, and
selenium. Areas being irrigated had lower groundwater selenium concentrations, while the groundwater
concentrations of barium,  molybdenum, vanadium, and zinc were elevated (Deason 1989). At other
agricultural sites, elevated groundwater concentrations of selenium, molybdenum, chromium, and
mercury are of concern (Deason 1987).

       Soils below drainage irrigation canals and basins have shown higher concentrations of selenium,
arsenic, and uranium than normal for the Western United States (Deason 1989). Selenium groundwater
contamination beneath irrigated  lands was also documented in Wyoming (Peterson 1988).

Metal Removal Processes in Soils

       The interaction of surface water and groundwater has resulted in selenium contamination of
groundwater in Wyoming (Peterson 1988). Sandy soils  performed minimal removal of boron and nickel
while the  percolate  water had no cobalt (Crites 1985). In general, studies of recharge basins receiving
large metal loads show that most of the heavy metals are removed either in the basin sediment or in the
vadose zone (Ku and Simmons  1986; and Hampson 1986).

       Removal of metals by soil may be accomplished through one of several processes,  including:
(1) soil surface association, (2) precipitation, (3) occlusion with other precipitates, (4) solid-state diffusion
into soil minerals, (5) biologic system or residue incorporation,  and (6) complexation and chelation
(Crites 1985).
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Adsorption-
        Dissolved metaJ ions are removed from stormwater mostly by adsorption onto the near-surface
particles in the vadose zone, while the paniculate metals are filtered out at the soil surface (Ku and
Simmons 1986). Studies of dissolved lead ions in recharge ponds in Jacksonville, Florida, found that
allowing the ponds to go dry between storms was counterproductive to the removal of lead from the
water during recharge (Hampson 1986). Apparently, the adsorption bonds were weakened during the
drying period.  Studies in Fresno, California, recharge basins found that lead, zinc, cadmium, and copper
accumulated at the soil surface with little downward movement over five years. However, the
microtopographic features, such as small depressions and basin inlet and outlet locations, influenced the
metal's  distribution in the soil (Nightingale 1987a).

        Similarities in water quality between the runoff water and the groundwater show that there is
downward movement of copper and iron in sandy and loamy soils. However, the other metals of concern
(arsenic, nickel, and lead) did not significantly move downward through the soil to the groundwater. The
exception to this was some downward movement of lead with the percolation water in the sandy soils of
Fresno  stormwater recharge basins (Nightingale 1987b).

Cation Exchange, Organic Complexation, and Chelation of Metals-
        In soils, heavy metals enter into general cation exchange reactions with clay and organic matter
and into chelation reactions with organic molecules. As the organic molecules are  decomposed, the
metals become free to react with iron and aluminum hydroxides, calcium, and other compounds.  These
new compounds are immobilized in the soil profile. The immobilization reactions are more pronounced
at high pH and in an aerobic environment.  Boron is adsorbed to iron and aluminum hydroxide coatings
on clay  minerals, to iron and aluminum oxides, to micaceous clay minerals, and to  magnesium hydroxide
coatings on weathering surfaces of ferro-magnesium minerals.  In sandy soils and quartz, boron is not
significantly immobilized (Bouwer 1985). Interactions of certain metals with phosphors can form either
soluble  or insoluble complexes. The  type of clay mineral also affects heavy  metal adsorption.  However,
the higher the cation exchange capacity (CEC) of the soil, the generally greater will be the binding of
metallic cations (Nightingale 1987a).

Precipitation of Metals--
        Selenium in agricultural drainage water is generally in its fully oxidized state, as selenate.
Although selenites can be readily precipitated from water, even in the presence of salts, selenate
precipitation is inhibited. The precipitation  process relies upon the bacteria which occur naturally in the
drainage water which convert the inorganic selenate to an organic complex.  Part of the selenate is
assimilated into the complex, part is reduced to a  lower oxidation state, and the rest is reduced to zero
valent selenium (Squires,  et al. 1987). Further testing confirms that selenite can be readily precipitated
from drainage water, even in the presence of salts, but selenate precipitation is inhibited in the presence
of nitrate and sulfate (Squires, et al. 1989). In central Florida, the dissolved iron concentrations in
recharge water is much greater than in the groundwater, indicating that dissolved iron ions are being
removed from the recharge water during percolation. The reduction of dissolved iron concentrations
resulted from precipitation of iron or complexation into other nonsoluble species (Schiffer 1989).

        Iron and manganese transformations in groundwater are controlled by both the oxidation-
reduction conditions and the acid-alkali balance in the water. The  migration  and diffusion speed of iron
(Fe+2) and oxygen is rather slow in water,  but is accelerated by iron  bacteria. The amount of iron
oxidized by iron bacteria is ten, or even hundreds of times, greater than that oxidized by the chemical
reaction alone  (Bao-rui  1988). In central Florida, zinc, which is more soluble than iron,  was commonly
found  in higher concentrations in groundwater than iron (Schiffer 1989).

Dissolved  Metal Concentration Increases in Groundwater-
       The dissolved iron concentration in the Magothy aquifer was greater after recharge than in the
                                              76

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native groundwater and in the recharge water itself. The observed increase in iron concentration from
less than 0.5 mg/L to 3 mg/L indicated a constituent of the recharge water reacting with the pyrite and
marcasite (FeSg) in the aquifer (Ragone 1977).  For the first twenty feet from the well in the aquifer, the
dissolved oxygen in the recharge water reacted with the pyrite to produce ferrous iron, sulfate, and
hydrogen ions, according to the following equation:
FeS2 + 7/2 O2 + H2O --> Fe+2 + 2
                                               2 H+
At distances greater than twenty feet, the dissolved oxygen concentration was zero. The reason for the
increase in the dissolved iron concentration was unknown (Ragone 1977).

Mobility--
        In dry recharge wells in Arizona, manganese was the only metal that was mobile in the nearly-
neutral vadose zone sediments and was the only metal to show up in the groundwater at elevated
concentrations (Wilson, et al. 1990).

        Experiments in Orlando, Florida, concerning metal mobility in soil and its resultant stability have
led to the ranking of pollutants in order of attenuation from recharge water:  zinc (most mobile) > lead >
cadmium > manganese > copper > iron > chromium > nickel > aluminum (least mobile)  (Harper 1988).
Other studies of metal pollutant mobility in soil have led to the generation of mobility classes, as shown
in Tables 23 and 32 (Armstrong and Llena 1992).
                                 TABLE 32.  METAL MOBILITY
Inorganic
Pollutant
                             Concentration
                             (ma/L)
        Mobility Class
Sandy Loam	
Silt Loam
Arsenic                             1.0
Arsenic                             0.01

Cadmium                           1.0
Cadmium                           0.01

Chromium                           1.0
Chromium                           0.01

Copper                             1.0
Copper                             0.01

Lead                                1.0
Lead                                0.01

Nickel                               1.0
Nickel                               0.01

Zinc                                1.0
Zinc                                0.01

Source: Armstrong and Llena 1992.
                                                   IV
                          IV
                                                                        IV
                                                   IV

                                                   IV
                                                   IV

                                                   IV
                                                   IV

                                                   III
                          IV
                          IV

                          IV
                          IV
                                                                        IV
                                              77

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General-
       Table 33 summarizes the principal removal mechanisms in the soil for each metal (Crites 1985).
The surface water heavy metals concentrations were the most significant variables in predicting the
concentrations of the heavy metals in the groundwater (Harper 1988).

Health and Ecological Effects

       Metals in groundwater can cause environmentaJ and ecological problems, as well as human
health problems. Groundwater contamination will mostly affect human  consumers of the groundwater,
although  the discharge of contaminated groundwaters into surface waters can also have deleterious
effects on aquatic organisms.

Environmental Problems-
       Boron concentrations in sago pondweed from several lakes and reservoirs affected by irrigation
water have been found to be large enough to damage sole consumers of that pondweed and is toxic,
especially to citrus crops (Bouwer and Idelovitch 1987). In Wyoming, boron and selenium concentrations
from local agriculture had concentrated in the wildlife in sufficient quantities to damage bird livers and
eggs, to reduce fish reproduction and to kill waterfowl (Peterson 1988; Deason  1989).  Molybdenum is
toxic to animals that forage on plants with high  molybdenum concentrations (Bouwer and Idelovitch
1987). Many different heavy metals also affect  aquatic organisms, including microinvertebrates, fish, and
plants.

Human Health Problems-
       Human health problems due to metal poisoning have been linked to water supplies. Iron and
manganese removal in most water supplies is primarily for aesthetic reasons and for taste.  However,
excess concentrations of certain elements, including arsenic, copper, lead and selenium, in the potable
water have caused disease outbreaks (Craun 1979). The following list  of human health effects is
summarized from Craun (1979) and Crites (1985):

       • Arsenic is readily adsorbed from the gastrointestinal system and/or the lungs and distributed
throughout the body where it can bioaccumulate. Symptoms of mild chronic arsenic poisoning include
fatigue and loss of energy, while symptoms of severe poisoning include gastrointestinal mucous
membrane inflammation, kidney degeneration,  fluid accumulation in the body, polyneuritis  and bone
marrow injury.

       • Barium enters the body through either inhalation or ingestion. Barium  ingestion can cause toxic
effects on the heart, blood vessels and nerves.

       • Cadmium, because of its similarities to zinc, will bind to sites on enzymes intended for zinc.
Symptoms of mild chronic poisoning include  proteinurea. Continued exposure to cadmium will lead to
renal degradation, respiratory disorders such as emphysema, gastric and intestinal dysfunctions, anemiz,
and hypertensive heart disease.  Exposures  to  very large quantities of cadmium have caused itai-itai
disease, erthyrocyte destruction, and testicular damage, but are unlikely in groundwater. All disease
outbreaks from very large doses of cadmium have resulted from direct industrial exposure.

       • Chromium is necessary for glucose tolerance in animals, including man, however, large
quantities of hexavalent chromium can cause tumors if inhaled or through skin contact.

       •  Copper is also essential for animals, and a lack of copper can cause nutritional anemia in
infants. Large doses of copper can produce  vomiting and liver damage.  Disease outbreaks have been
traced to  copper leaching from plumbing.
                                              IS

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TABLE 33.  METAL REMOVAL MECHANISMS IN SOIL
Principal Forms
Element
Arsenic
Barium
Cadmium
Chromium

Cobalt
Copper


Iron

Lead
Manganese
Mercury

in Soil Solution
AsO4 -3
Ba+2
Cd+2
complexes
chelates
Cr+3
Cr+6
CrO4 -2
Co+2
Co+3
Cu+2
Cu(OH) +
anionic
chelates
Fe+2
Fe+3
polymeric
forms
Pb+2
Mn+2
Hg+
HgS
HgCI4-2
OJJB*
Principal Removal Mechanisms
Strong associations with clay fractions of soil.
Precipitation and sorption onto metal oxides and
hydroxides.
Ion exchange, sorption, and precipitation.
Sorption, precipitation, and ion exchange.

Surface sorption, surface
complex ion formation,
lattice penetration, ion
exchange, chelation, and
precipitation.
Surface sorption, surface complex ion formation,
ion exchange, and chelation.


Surface sorption and surface complex ion.

Surface sorption, ion exchange, chelation, and
precipitation.
Surface sorption, surface complex ion formation,
ion exchange, and chelation, precipitation.
Volatilization, sorption, and chemical and microbial
degradation.

                                                  (continued)
                     79

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                                  TABLE 33. (CONTINUED)
Element
Nickel

Selenium


Silver

Zinc
Principal Forms
in Soil Solution
Principal Removal Mechanisms
Ni+2

SeO3 -2
SeO4-2

Ag+

Zn+2
complexes
chelates
Surface sorption, ion exchange, and chelation.

Ferric-oxide selenite complexation.


Precipitation

Surface sorption, surface complex ion formation,
lattice penetration, ion exchange, chelation, and
precipitation.
Source: Crites 1985.
                                             SO

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        • Iron, common in most metal pipes, is not a desired constituent in drinking water due to taste,
fixture staining and deposit accumulation.

        • Lead enters the body by either inhalation or ingestion and accumulates in the liver, kidney and
bones.  Chronic high lead exposures can lead to burning in the mouth, severe thirst, vomiting, and
diarrhea. Acute toxicity starts with convulsions and anemia, and may proceed to peripheral nerve
disease, joint swelling, kidney degeneration, mental confusion, brain damage, and eventually, death.

        • Manganese, like iron, is objectionable in drinking water because it affects taste, stains fixtures,
spots laundered clothes and collects in distribution systems.

        • Mercury damages while it  bioaccumulates in the liver, kidney and brain.  Chronic exposure
results in mouth and gum inflammation, salivary gland swelling, teeth loosening, kidney damage, muscle
spasms and personality changes. Acute mercury poisoning causes severe diarrhea, vomiting, kidney
damage and death. Mercury also deforms fetuses.

        • Chronic selenium poisoning results in red staining of the fingers, teeth and hair; depression;
nose and throat irritation; upset stomach; and skin rashes. Acute poisoning is characterized by
nervousness, vomiting, convulsions, hypertension, and respiratory failure.

        • Silver poisoning results in  skin, eye and mucous membrane discoloration and silver is retained
in the body tissue indefinitely.

        • Zinc, although it is necessary for life, affects the taste of water if in excessive amounts.


GROUNDWATER CONTAMINATION ASSOCIATED WITH SALTS AND OTHER DISSOLVED
MINERALS

Definition

        The dissolved minerals of concern in groundwater contamination are primarily salts. These salts
include compounds containing combinations of calcium, potassium, sodium, chloride, fluoride, sulfate, or
bicarbonate.

Examples of Salts Contaminating Groundwater

        Increasing chloride concentrations in groundwater have been used as an indicator of early
groundwater contamination in Great Britain (Lloyd, et al. 1988).  When using rapid infiltration for
recharge, inorganic dissolved solids are of concern and include chloride, sulfate, and sodium  (Crites
1985). Sources of the dissolved solids include naturally occurring salts, landfill leachate, leaky
sewerage, cesspool leachate, and other urban and agricultural sources.

Natural Occurrence--
        On Long Island, New York, one of the  sources of dissolved solids in the recharge water was salt
spray from the sea (Seabum and Aronson  1974).  Salt water from an adjacent surface water body can
infiltrate into the aquifer if the hydraulic gradient flows in that direction. A brackish lagoon near
Narbonne, France has contaminated groundwater (Razack, et al. 1988).

Urban Areas-
       Satt applications for winter traffic safety is a common practice in many northern areas and the
sodium and chloride, which are collected in the snowmelt, travel down through the vadose zone to the
                                              81

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groundwater with little attenuation. Fertilizer and pesticide salts also accumulate in urban areas and
leach through the soil to the groundwater (Merkel, et al. 1988).  In Arizona, stormwater infiltration in dry
wells dissolves native salts in the vadose zone which are then carried to the groundwater (Wilson, et al.
1990).

        Investigations of groundwater near a landfill in Lee County, Florida, showed that the
concentrations of sulfates, potassium, chloride, and sodium were ten to 100 times greater than in the
unaffected aquifer (Boggess 1975). Elevated sulfate concentrations in the groundwater beneath the city
center in Narbonne, France, originated from leaking sanitary sewerage. The use of saltpeter (potassium
nitrate) in the numerous wine cellars in the area  also contaminated the groundwater (Razack, et al.
1988). Elevated chloride, sodium, and sulfate groundwater concentrations resulted from cesspool
leachate on  Long Island, New York, (Smith and Myott 1975) and from septic tank leachate in Florida
(Waller, etal. 1987).

Agricultural Operations--
        Major sources of dissolved solids in groundwaters in agricultural areas include fertilizers and
pesticides. Elevated groundwater total dissolved solids concentrations of 200 mg/L and chloride and
sulfate concentrations of about 10 mg/L and 20 mg/L, respectively, have been reported on Long Island,
New York (Seaburn and Aronson 1974). The concentrations of sodium, chloride, and sulfate vary with
the season and are likely related to precipitation  and irrigation patterns (Hampson 1986).

        In areas of sustained irrigation, some leaching must occur periodically to remove the salts that
accumulate in the root zone of the crops (Power and Schepers 1989). Evapotranspiration concentrates
the salts in the root zone which, during irrigation, are flushed into the vadose zone and eventually into
the groundwater (Schmidt and Sherman 1987).  Spray irrigation  with secondary treated effluent can
increase chloride concentrations and specific conductance in shallow aquifers (Brown 1982). Grazing
cattle return  seventy-five to eighty percent of the of the potassium in their forage to the soil
(Reichenbaugh  1977).

        High groundwater salinity has  been noted in the San Joaquin Valley, under the agricultural areas
near Fresno, California, in irrigated areas of Arizona and New Mexico, where the salinity has been
increasing since the 1930s, and in the Corn Belt  and Great Lake states (Schmidt and Sherman 1987;
Deason 1989; Bouwer 1989; Sabol, et al. 1987; and Mossbarger and Yost 1989). Most salts in
groundwater below irrigated areas have resulted from the leaching of natural salts from the arid soils.
Use of sludge as fertilizer on sandy loam soil in New Jersey increased the total dissolved solids
concentration of the groundwater (Higgins 1984). On Long Island, New York, recharge of the
groundwater has led to an increase in the sodium and chloride concentrations above the background
concentrations (Schneider, et al. 1987).  Mathematical modeling has led to the conclusion that salt from
agricultural return flows is the greatest single contributor (about 40%) of salt to Upper Midwest
groundwater (Schmidt and Sherman 1987).

Salt Removal Processes in Soils

        Most salts are not attenuated during movement through soil. In fact, salt concentrations typically
increase due to  leaching of salts out of soils. Groundwater salt concentration decreases may occur with
dilution of less saline recharging waters.  Use of lower salinity water as recharge water at the Leaky Acres
stormwater recharge facility  in Fresno, California, was shown to  decrease the salt concentrations in the
groundwater (Nightingale and Bianchi  1977a). Reduction in the  pH of groundwater, such as would result
from nitrification and the biodegradation of carbonaceous substances, resulted in the dissolution of soil
minerals and subsequent increases in  the total dissolved solids concentrations and the hardness of
groundwater at the Whittier Narrows site in Los Angeles County, California (Nellor, et al. 1985).  This
effect was noted in  Florida during the deep-well injection of acidic, high-oxygen  demanding industrial
waste. At first, neutralization of the waste occurred through solution of the calcium carbonate in the
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limestone. Later, the calcium concentration in the aquifer increased and the pH decreased, but the
effects have still been confined to the lower strata of the Floridan aquifer (Goolsby 1972).

Leaching of Salts--
        Salt leaching is a greater concern in arid areas of the United States because the irrigation
requirements for the arid areas are great and  the irrigation water collects the salts that have been
concentrated in the  soil by increased evapotranspiration.  Salts that are still in the percolation water after
it travels through the vadose zone will contaminate the groundwater (Sabol, et al. 1987; and Bouwer
1987). The rate of contaminated water movement in a water-table aquifer is highest when the water
table is highest (Boggess 1975).

        Nonuniform irrigation and preferential flow allows the percolation water to reach the groundwater
much faster and reduces the amount of salt removal that could occur during slower water passage
through the soil (Bouwer 1987), especially for the chloride ion, which is not readily adsorbed.  Irrigation
efficiency and interval significantly affect groundwater chloride concentrations. For example, fields in
Arizona and New Mexico that were irrigated at nearly 100% efficiency had much higher chloride
concentrations in the root zone of the soil (Sabol, et al. 1987). The higher the salt concentration of the
soil solution, the higher the soil hydraulic conductivity will be for a given sodium adsorption ratio  (SAR)
(Bouwer and Idelovitch 1987).  Schmidt and Sherman (1987) found a direct relationship between
concentrations of groundwater nitrates and salts.

Solubility Equilibrium of Salts-
       An equilibrium exists between the recharge water and the high groundwater for  calcium and total
dissolved solids. For chloride, sodium, and sulfate, reductions in concentrations entering the recharge
system are likely accounted for by differences in seasonal precipitation, with a higher loading  in the
summer than in the  winter. Changes in the groundwater concentration reflect these loading differences
(Hampson 1986). Potassium exchanges with hydrogen ions on the clay during percolation. Other
exchanges cause the calcium and magnesium concentrations to be much greater than had been
predicted (Ragone 1977).  Deep-well injection waters have shown an increase in alkalinity and
bicarbonate concentrations, reflecting the mineralization of the organic compounds. Dissolved calcium
and  bicarbonate are the primary products of limestone dissolution. Many parameters in natural
groundwater systems are controlled, or are influenced, by the calcium carbonate equilibrium system.

Removal of Salts in Soil-
       The soil is not very effective at removing most salts. Studies of depth of pollutant penetration in
soil have been studied in relation to a shallow, unconfined aquifer and have shown that sulfate and
potassium concentrations decrease with depth, while sodium,  calcium, bicarbonate and  chloride
concentrations increase with depth in the soil. The dissolution of the aquifer material may be the source
of many of the chloride, bicarbonate, calcium, and sodium ions (Close 1987). The same increase in salt
concentrations with  depth was noted in the agricultural (irrigated) areas of Arizona and New Mexico, and
may be a result of little water and salt uptake by the plants.  On Long Island, New York,  it was  noted that
the heavy metals load was significantly reduced during passage through the soil, while chloride was not
reduced significantly. This indicated that the soil does not contain an effective removal process for
chloride salts (Ku and Simmons 1986). However, fluorine is removed  in soil through sorption and
precipitation processes (Crites 1985).

       Chloride and sulfate concentrations from septic tanks increased with depth below the leach field,
but were rapidly diluted downgradient. The primary controls on the leachate movement are the lithology
and layering of the geologic materials, hydraulic gradient slopes, and the volume and type of use the
septic system receives. Dilution occurs more rapidly in limestone than in sand (Waller, et al. 1987).

       Once contamination with salts begin, the movement of salts into the groundwater can be rapid.
The salt concentration may not lessen until the source of the salts is removed. The cations sodium,
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potassium, calcium, and magnesium appeared in a shallow aquifer three to six months after the source
water was applied to the soil (Higgins 1984).

        Control of groundwater salt contamination in agricultural areas should result from maintaining
irrigation rates at near the minimum leaching rate (Bouwer 1987).  This control, with other crop
management practices, will slow the leaching rate of the salt to the groundwater (Lee 1990). Reduction
of the dissolved solids concentrations will decrease by dilution through recharge with "cleaner" water
(Nightingale, et al. 1983).

Health and Other Effects

        Besides direct effects, dissolved solids concentrations can also affect the pH of the water.
Problems may then  be caused by the effect of pH on high concentrations of undesirable elements, such
as iron, manganese and aluminum in acid waters, and sodium, carbonates and bicarbonates in alkaline
waters (Bouwer 1987).

Human Health Problems--
        High total dissolved solids concentrations are objectionable because of possible physiologic
effects, mineral taste, and corrosion. High concentrations of chloride ions in water affects its taste and
accelerates the corrosion of pipes and household appliances. Excess sodium can cause health
problems, especially for people who are on sodium-restricted diets, due either to hypertension, edema
from congestive cardiac failure and pregnant women with toxemia. High concentrations of sulfate ions
affect the taste of the water and are a laxative to humans (Crites 1985). Although small quantities of
fluoride are recommended in water by the American Dental Association, excessive amounts of fluoride
can mottle, instead of protect, teeth.  The National Toxicity Program has classified fluoride as an
equivalent carcinogen in mice.

Agricultural Problems-
        Sodium can adversely affect crops by causing leaf burn in almonds, avocados and stone fruits.
Bicarbonate in spray applied irrigation will leave an unappealing white residue after the water
evaporates. Sulfate affects the growth of many plants and can cause leaf burn in still others (Bouwer
and Idelovitch 1987).


GROUNDWATER CONTAMINATION ASSOCIATED WITH  SUSPENDED SOLIDS

Definition

        The term suspended solids is usually defined as the  non-filterable portion of a water sample after
filtering through a 0.45 micron filter. This definition does not accurately describe the fate of this material.
Depending on specific gravity and particle sizes, the "suspended"  material also includes floatable matter,
rapidly settleable matter, and matter that could settle out of suspension over highly variable periods of
time.

Soil Removal Processes of Suspended Solids

        Suspended solids are of concern  because of the potential  for clogging the infiltration area (Crites
1985).  The recharge water should be of low salinity and turbidity (Nightingale and Bianchi 1977b).
When the groundwater salinity was reduced by using less salty recharge water in Fresno, California, the
turbidity of the groundwater increased. Leaching of poorly crystallized and extremely fine colloids from
the soil and into the groundwater had occurred. This effect was only temporary,  with the groundwater
returning to its original turbidity soon after recharge began and was not observed outside of the recharge
basin area. Changes in the recharge water salinity, however, may cause this effect to return (Nightingale

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andBianchi1977b).

       Laboratory studies on the movement of fine participate matter through sand aquifers found that
the movement is controlled first by the nature of the particle, second by the cation and anion
concentrations of the percolating water, and third by the pore size distribution of the soil to the aquifer
(Nightingale and Bianchi 1977b). As water flows through passages formed by the soil particles,
suspended and colloidal particles too small to be retained at the surface are thrown off their streamline
through hydrodynamic actions, diffusion, Impingement, and sedimentation. The particles may then be
adsorbed onto stationary soil particles. The degree of trapping and adsorption of suspended solids by
soils is a function of the suspended solids concentration and size distribution, soil characteristics, and
hydraulic loading (EPA 1992). The soil profile will filter out suspended solids from recharge water and,
once the particles are in the soils, biological and chemical degradation may occur.  Fine to medium
textured soils remove essentially all suspended solids from the wastewater by straining (Bouwer 1985),
while coarse textured soils enable deeper penetration of suspended and colloidal particles in the soil
(Treweek1985).


DISSOLVED  OXYGEN GROUNDWATER PROBLEMS

       Dissolved oxygen (DO) in any water is controlled not only by how much DO exists and how much
can be produced by aquatic plants, but also by the oxygen needs of the other organisms and compounds
in the water. As groundwater recharging proceeds, dissolved oxygen is depleted due to the proliferation
of iron bacteria and T. thioparus, which leads to anaerobic conditions in the groundwater (Bao-rui 1988).
Increases in both dissolved oxygen and temperature should  increase virus inactivation (Jansons, et al.
1987b). Groundwater has no natural reaeration process available, so once depleted, groundwater DO will
remain very low.

       COD  levels from injection well wastes were reduced approximately eighty percent within
relatively short distances from an injection point near Pensacola, Florida (Ehrlich, et al. 1979b). During
recharge of the Magothy aquifer at Bay Park, New York, it was found that dissolved oxygen persisted for
about twelve feet away from the recharge well.  At greater distances, the water is essentially oxygen free.
Two occurrences can account for the oxygen loss from the recharge water as it moves through the
aquifer. First, oxygen reacts with pyrite in the formation to produce ferrous iron, sulfate and hydrogen.
Second, microbial respiration associated with waste stabilization depleted the oxygen supply (Ehrlich, et
al. 1979a).
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                                         SECTION 4

                     TREATMENT BEFORE DISCHARGE OF STORMWATER


       One of the best overall urban runoff control strategies may be to encourage infiltration of
stormwater to replace the natural infiltration capacity lost through urbanization. This significantly reduces
the volume of runoff discharged to surface waters, including pollutants. This strategy also improves
groundwater conditions by reducing the lowering rate of urban water tables. Exfiltration from groundwater
into local streams during dry periods can also substantially improve receiving water biological conditions.
The EPA (1983) concluded, as part of the Nationwide Urban Runoff Program, that stormwater can be
safely infiltrated to groundwater, if done carefully. Issues that must be considered include a knowledge of
pollutant concentrations from different areas, pollutant removals  in the vadose zone, and necessary
pretreatment that may  be needed before infiltration. This report section reviews characteristics of urban
runoff pollutants that will affect their fates in treatment processes, along with reported performance of
stormwater treatment devices.


SOLUBILITIES AND TREATMENT POTENTIALS OF SIGNIFICANT URBAN RUNOFF TOXICANTS

       This section discusses chemical reactions, solubilities and fates of significant urban runoff
pollutants. The information presented here is based upon a review of the urban runoff and  environmental
chemistry literature and addresses toxic heavy metals and  organic  pollutants that have been detected in
various urban runoff waters. This information can be used to identify the potential removal  mechanisms
that may be available in stormwater control practices and to identify the potential transport and fate
mechanisms of the pollutants in the surface or subsurface receiving waters.

Arsenic

Arsenic Sorption-
       Arsenic can be adsorbed onto clays, iron oxides, inorganics (Callahan, et al. 1979).

Arsenic Fate/Treatment-
       Callahan, et al. (1979) stated that all of the potential environmental fates, except for photolysis,
can be important for arsenic. Arsenic can either remain suspended or accumulate in sediments
(Callahan, et al. 1979). Phillips and Russo (1978) stated that arsenic may be bacterially methylated,
much like mercury, to form highly toxic methylarsenic or dimethylarsenic. These methylated forms of
arsenic are very volatile and are readily oxidized to less toxic forms.

Cadmium

Cadmium Filterable Fraction, Solubility and Sorption-
       Forty to fifty percent of the cadmium in roof,  loading docks, and street runoff sampled by Pitt and
Barren (1990) was found in filtered sample components, while the other stormwater source areas all  had
less than 20% associated with the filtered sample component. Pitt and Amy (1973) studied the
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leachability of cadmium from street dirt, along with other metals, and found that in typical urban runoff
concentrations, leachable cadmium values of less than 1 (.ig/L occurred in moderately hard water after an
exposure of 25 days. This leachable fraction was 14 percent of the total cadmium in the mixture. Wilber
and Hunter (1980), in an urban receiving water study in Lodi, New Jersey, found that with most low flows
in the Saddle River, the cadmium was mostly dissolved. However, during wet weather conditions, most
of the cadmium was associated with undissolved, or solid particulates. Callahan, et al. (1979) stated that
adsorption of cadmium onto organics, clays, hydrous iron and  manganese oxides is important in polluted
water.

Chromium

Chromium Filterable Fraction--
        Filtered stormwater samples generally contained less than 10 percent of the total chromium
detected by Pitt and Barren (1990). Pitt and Amy (1973) found that the leachable fraction of chromium
associated with street dirt in moderately hard water was about 4 ng/L or about 0.3 percent of the total
chromium in the mixture.
Copper Filterable Fraction, Sorption, and Solubility-
       The filtered stormwater samples analyzed by Pitt and Barren (1990) generally had less than 20
percent of the total copper concentrations. Wilber and Hunter (1980), in a study of an urban river in Lodi,
New Jersey, found that the readily available copper (at a pH of about 7) was about 13 percent of the
street dirt and runoff solids total copper content.  Pitt and Amy (1973) found that the leachable fraction of
copper associated with street dirt was about 160 ng/L, or about 36 percent of the total copper in the
mixture, with  moderately hard water conditions. The adsorption of copper can reduce its mobility and
enrich suspended and settled sediments (Callahan, et al. 1979).  Copper is absorbed onto organics, clay
minerals, hydrous iron and manganese oxides.

Iron

Iron Filterable Fraction, Sorption, and Solubility-
       Pitt and Amy (1973) found that the  leachable fraction of iron in  street dirt was about 50 ng/L, or
much less than 1 percent of the total iron in a mixture with moderately hard water. They also stated that
the principal inorganic iron forms, near pH 7, are iron oxide, hydroxide, sulfate, nitrate and carbonate.
Phillips and Russo (1978) stated that the soluble ferrous form of iron (+2) is readily oxidized to the
insoluble ferric, or trivalent (+3) state in most natural surface waters. A substantial fraction of iron in
natural waters is therefore associated with suspended solids.

Lead

Lead Filterable Fraction, Sorption, and Solubility-
       The filtered stormwater samples analyzed by Pitt and Barren (1990) generally had less than 20
percent of the total lead concentrations. The EPA (1976) stated that most lead salts  are of low solubility.
The aqueous solubility of lead ranges from  500 ng/L in soft water to 3 ng/L in hard water (EPA 1976).
Durum (1974) stated that lead carbonate and lead hydroxide are soluble lead forms  at pH vales of 6.5, or
less, with low alkalinity conditions (less than 30 mg/L alkalinity as CaCC>3). The soluble lead
concentrations under these conditions can reach 40 to several hundred ng/L.  If the alkalinity is greater
than 60 mg/L and if the pH is near 8, however, the dissolved lead would be less than 10 ng/L. Callahan,
et al. (1979) stated that lead carbonate and lead sulfate control lead solubility under aerobic conditions
and normal pH values.  Lead sulfide and lead ions, however, control lead solubility in anaerobic
conditions. In polluted water, the organic complexes of lead are most important in controlling lead
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solubility.  Phillips and Russo (1978) stated that most lead is probably precipitated in natural waters due
to the presence of carbonates and hydroxides.

        Pitt and Amy (1973) found that the leachable fraction of lead in a street dirt and water mixture
was about 40 jig/L, or about 3 percent of the total lead, in moderately hard water. Wilber and Hunter
(1980) found that the readily available fraction of lead was about 20 percent of the total lead in street dirt
and runoff solids. They also found that under most low flow river conditions, most of the lead was
dissolved, but under wet weather conditions, most of the lead was insoluble. Solomon and Natusch
(1977) also examined the solubilities of lead associated with street dust. They found solubilities ranging
from 500 to 5000 ng/L which was 0.03 to 0.3 percent of the initial mixture total lead concentration.
However, the test mixture of street dirt with water was very high (1750 mg/L lead).  Rolfe and Reinbold
(1977) found that about 80 percent of the lead in stream water was insoluble and associated with
suspended solids.


Nickel

Nickel Filterable Fraction-
        Very few of the filtered stormwater samples analyzed by Pitt and Barren (1990) had detectable
(>1 ng/L) nickel concentrations. Wilber and Hunter (1980) found that the readily available nickel fraction
of street dirt and runoff solids was about 4 percent at close to neutral pH conditions. Pitt and Amy (1973)
found that the leachable fraction of nickel associated with street dirt, in a moderately hard water mixture,
was about 30 ng/L, or about 7 percent of the total nickel in the mixture.

Mercury

Mercury Fate/Treatment-
        Callahan, et al. (1979) stated that  almost all of the environmental processes are important when
determining the fate of mercury in aquatic  environments. Phillips and Russo (1978) reported that
inorganic mercury concentration, availability of inorganic mercury,  pH, microbial activity and redox
potential all affect mercury methylation rates. In general, more methylmercury is produced when more
inorganic mercury is present.  Chemical agents which precipitate mercury, such as sulfide, reduce the
availability of mercury for methylation, but only when present in large quantities. At neutral pH values,
the primary product of mercury methylation is monomethylmercury. Methylation can occur under both
aerobic and anaerobic conditions, but more mercury is produced when more bacteria are present.

Zinc

Zinc Filtered Fraction, Solubility and Sorption-
        Filtered stormwater samples contain most of the total zinc concentrations observed, except for
storage area and vehicle service area runoff (Pitt and Barren 1990). Durum (1974) stated that the
solubility of zinc is less than 100 ng/L at pH values greater than 8, and less than 1,000 (j.g/L for pH
values greater than 7, if there is a high concentration of dissolved carbon dioxide. Phillips and  Russo
(1978) stated that zinc sulfates and halides are soluble in water, but zinc carbonates, oxides and sulfides
are insoluble. Wilber and Hunter (1980), in a study of an urban stream near Lodi, New Jersey, found that
the readily available zinc in street dirt and  runoff solids was about 17 percent of the total zinc.  Most  of
the zinc in the river during low flow conditions was dissolved, while during wet weather it was mostly in
the solid form.  Pitt and Amy (1973) found that the leachable fraction of zinc was about 170 ng/L, or
about 8 percent of the total street dirt zinc, in a moderately  hard water mixture.
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Phenols and Chlorophenols

Phenols and Chlorophenol Filtered Fraction--
       The EPA (1979) stated that the solubility of chlorinated phenols in water solutions is low, but
increases when the pH increases. Phenoxide salts are also more soluble than the corresponding phenol
in water with neutral pH conditions.

Phenols and Chlorophenol Fate/Treatment--
       Phenol may be biochemically hydroxylated to ortho and paradihydroxybenzenes and readily
oxidized to the corresponding benzoquinones (EPA 1979). These may in turn react with numerous
components of industrial waters,  sewerage or other waste streams such as mercaptans, amines, or the -
SH, or -NH group of proteins.  Phenol has also been  shown to be highly reactive to chlorine in dilute
solutions over a wide pH range.  The chlorination of phenol to toxic chlorophenols has been
demonstrated under conditions similar to those used  for disinfection of wastewater effluent.

Pentachlorophenol (PGP)

Pentachlorophenol Filtered Fraction-
       PCP is slightly soluble in water, while PCP salts are highly soluble in water (EPA 1979).

Pentachlorophenol Fate/Treatment--
       PCP can undergo photochemical degradation in solutions in the presence of sunlight, with
subsequent formation of several  chlorinated benzoquinones (EPA 1979).  Sodium-PCP can be
decomposed  directly by sunlight  with the formation of numerous products. Microorganisms have also
been reported to metabolize PCP  PCP has also been reported to persist in warm and moist soils for a
period of one  year.

2.4-Dimethvlphenol (2.4-DMP)

2,4-Dimethylphenol Filtered Fraction-
       2,4-DMP is slightly soluble in water (EPA 1979).

General Polvcvclic Aromatic Hydrocarbons (PAHs)

PAH Filtered  Fraction-
       PAHs are basically insoluble in water (Callahan, et al. 1979).

PAH Fate/Treatment--
       These materials will be adsorbed onto suspended particulates and biota.  The dissolved portion
of these compounds can undergo direct photolysis at a rapid rate.  Biodegradation and biotransformation
by benthic organisms of PAH contaminated sediments is believed to be their ultimate fate (Callahan, et
al. 1979). Because of the low solubility of PAHs in water, biological treatment has little  benefit. However,
because of their attraction to solids, physical solids separation processes can be very effective in
reducing PAH concentrations (PHS 1981). It would be very difficult to sufficiently  reduce PAH
concentrations from water contaminated by stormwater to remove the cancer risk associated with their
long-term ingestion.

Benzo (a) Anthracene

Benzo (a) Anthracene Filtered Fraction--
       No detectable (>1 ng/L) benzo (a) anthracene was found by Pitt and  Barren (1990)  in filtered
stormwater sample fractions. The solubility of benzo (a) anthracene in water is about 10 to 45 (j.g/L
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 (Verschueren 1983).

 Benzo (a) Anthracene Fate/Treatment-
        More than half of the benzo (a) anthracene was adsorbed onto waterborne particulates (including
 aggregates of dead plankton and bacteria) after just 3 hours exposure (Verschueren 1983). Physical
 treatment of sewage can reduce the benzo (a) anthracene concentrations by about 80 percent, while
 biological treatment can remove almost all of the benzo (a) anthracene, leaving less than 0.1 ng/L in the
 effluent. Ozonation reduced the benzo (a) anthracene concentrations in sewage effluent by about 95
 percent, while chlorination reduced the concentrations by  about 50 percent.

 Benzo (b) Fluoranthene

 Benzo (b) Fluoranthene  Fate/Treatment-
        Physical sewage treatment processes reduced benzo (b) fluoranthene concentrations by 50 to 80
 percent, while biological processes provided almost complete removal (Verschueren 1983). Chlorination
 alone accounted for about a 33 percent  reduction. Water treatment reduced initial 0.15 (ig/L benzo (b)
 fluoranthene  concentrations by about  70 percent. Sedimentation in a storage reservoir only slightly
 reduced the concentrations.

 Benzo (k) Fluoranthene

 Benzo (k) fluoranthene Fate/Treatment--
        Physical sewage treatment reduced concentrations of benzo (k) fluoranthene from 8 to about
 2 ng/L (Verschueren 1983). Biological treatment further reduced the concentrations to less than 0.1
 Chlorination alone reduced the concentrations by about 60 percent, from an initial value of about
 70
 Benzo (a) Pyrene

 Benzo (a) pyrene Filtered Fraction-
        Benzo (a) pyrene's solubility is about 3 ng/L (Verschueren 1983).

 Benzo (a) pyrene Fate/Treatment-
        Benzo (a) pyrene can be degraded in soil that is inoculated with special bacteria, with as much
 as 80 percent destroyed after eight days (Verschueren 1983). In natural estuarine waters, its degradation
 rate is only about 2 ng/L destroyed per 1,000 days. Its volatilization half-life is about 1,000 hours (40
 days) in waters moving about 1 m/sec with winds of about 2 m/sec. The volatilization half-life extends to
 about 1 0,000 hours (400 days) for still water and calm air, and decreases to about 400 hours (20 days)
 for very violent mixing conditions. About 70 percent of a benzo (a) pyrene mixture, having an initial
 concentration of 3 ng/L, was adsorbed onto particles after three hours.

        From 90 to 99 percent removal of benzo (a) pyrene was found using  activated carbon water
treatment in waters having initial concentrations of 5 to 50 (ig/L (Verschueren 1983). Chlorination (6 mg/L
 CI2) also reduced initial concentrations of 50 (ig/L benzo (a)  pyrene by 98 percent. Physical wastewater
treatment reduced benzo (a) pyrene concentrations by about 65 to 95 percent, and biological treatment
further reduced these concentrations by another 50 to 99 percent.

Fluoranthene

Fluoranthene Filtered Fraction-
       The observed median filterable portion of fluoranthene in stormwater (in the range of 0.5 to
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14 ng/L) was about 85 percent of the total sample concentration (Pitt and Barron 1990). The water
solubility of fluoranthene is about 200 ng/L (Harris 1982).

Fluoranthene Fate/Treatment--
       Harris (1982) reported that sedimentation processes was the most important rernoval mechanism
for fluoranthene, with removals of about 65 percent. Biological treatment increased the removal to about
95 percent. Verschueren (1983) also reported that physical sewage treatment processes reduced initial
fluoranthene concentrations of 3 to 45 (ig/L by about 60 percent, and biological treatment further reduced
the fluoranthene by another 80 percent. Water treatment reduced the raw water fluoranthene
concentrations of 0.15 ng/L by about 50 percent using filtration, and by another 50 percent by
chlorination. Storage in a reservoir reduced the fluoranthene concentrations by less than 10 percent.

Naphthalene

Naphthalene Solubility and Filtered Fraction-
       The observed median filterable portion of naphthalene (in the range of 7 to 82 ng/L) in runoff
samples was about 25 percent (Pitt and Barron 1990). At about 32 mg/L, the solubility of naphthalene is
quite high compared to other PAHs (Howard 1989). Naphthalene is moderately adsorbed by soils and
sediments,  but at a much less extent than for other PAHs. It is weakly sorbed by sandy soils, and tests
have found that less than one percent was sorbed by particulate matter in a variety of surface waters
(Howard 1989).

Naphthalene Fate/Treatment--
       In rapidly flowing streams, volatilization accounted for about 80 percent and sediment adsorption
accounted for about 15 percent of the removal of naphthalene from the water column (Howard 1989). In
deeper and slower moving  water, biodegradation (having a half-life of about 1 to 9 days) was probably
the most important fate mechanism. Adsorption onto sediments is probably only a significant removal
mechanism in waters having high solids concentrations and slow moving waters, such as in lakes.
Photolysis degrades naphthalene in surface waters with a half-life of about 3 days, but is much less
efficient at deeper waters. In 5 meter deep water, the photolysis half-life was about 550 days. The
presence of algae can substantially increase the photolysis rate of naphthalene.

       Howard (1989) reported that naphthalene in water biodegrades after a short acclimation period.
Bacteria can only utilize soluble naphthalene, however. Biodegradation of sediment bound naphthalene
is 8 to 20 times faster than  in water. In heavily contaminated sediment, the biodegradation half-life is
about 5 hours, but can be longer than 3 months in less contaminated sediments. No anaerobic
biodegradation of naphthalene in laboratory tests was observed after 11 weeks. The evaporation half-life
of naphthalene in surface waters is about 5 hours for moderate current and wind conditions. The
expected half-life of naphthalene in surface waters due to evaporation losses is expected to be about 50
hours in rivers and 200 hours in lakes. Microbial degradation rates were about 0.1  ng/L per day. Less
than one percent of the naphthalene was sorbed to particles in water after 3 hours exposure. Ion
exchange water treatment was close to 100 percent effective and the evaporation half-life of
naphthalene was reported to be about 7 hours at a water depth of 1 meter. Naphthalene would be readily
removed by physical and biological treatment processes.

Phenanthrene

Phenanthrene Filtered Fraction-
       Its solubility in water is relatively high for a PAH, being about 1,000 (xg/L (Verschueren 1983).
Pitt and Barron (1990) did not detect any filterable phenanthrene in stormwater above the detection limit
(about 1
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Pyrene Filtered Fraction-
       The observed median filterable portion of pyrene (about 1 to 19 ng/L) in stormwater samples was
about 95 percent (Pitt and Barron 1990). Its solubility in water is about 160 ng/L (Verschueren 1983).

Pyrene Fate/Treatment--
       Pyrene can be photo-degraded from soils by UV radiation (Verschueren 1983). Chlorination at
6mg/L chlorine for 6 hours decreased initial pyrene concentrations of 27 ng/L by about 25 percent
(Verschueren 1983). Physical wastewater treatment processes decreased pyrene concentrations by
about 80 percent, and biological processes further decreased the pyrene concentrations by about 98
percent. Reservoir storage of river water decreased pyrene concentrations by about 25 percent. Filtration
further decreased the concentrations by another 40 percent, and chlorination further decreased the
pyrene concentrations by another 60 percent.


Chlordane

Chlordane Filtered Fraction-
       Chlordane's solubility in water is about 60 ng/L (Verschueren 1983). Pitt and Barron (1990) did
not find any chlordane, greater  than the detection limit of about 0.3 ng/L, in the filtered portion of
stormwater samples.

Chlordane Fate/Treatment--
       The persistence of chlordane in water in sealed jars exposed to sunlight indicated a 15 percent
decrease after 8 weeks. Chlordane was reduced by 75 to 100 percent from soils after 3 to 5 years
(Verschueren 1983).

Butyl Benzyl Phthalate

Butyl Benzyl Phthalate Filtered  Fraction-
       The only observed filterable value of butyl benzyl phthalate (BBP) (16 |Kj/L) detected my Pitt and
Barron (1990) in stormwater was 33 percent of the total value.  BBP's solubility in water is about 3 mg/L
(Verschueren 1983).

Butyl Benzyl Phthalate Fate/Treatment-
       BBP does undergo biodegradation with relatively complete removals within one month
(Verschueren 1983). Biodegradation  using activated sludge from a wastewater treatment plant was
reported to be 99 percent effective after 48 hours. Biodegradation in natural river waters was about 80
percent effective after one week of exposure. Photodegradation and chemical degradation (through
hydrolysis)  of BBP is  much less effective, with reported half-lifes of greater than 100 days.

Bis (2-chloroethyl) Ether

Bis (2-chloroethyl) Ether Filtered Fraction-
       The two observed filterable fractions of Bis (2-chloroethyl) ether (BCEE) (17 and 23 ng/L) found
by Pitt and  Barron (1990) in stormwater were 19 and 50 percent of the concentrations observed in the
unfiltered samples.  BCEE solubility in water is about  1 mg/L (Howard 1989). It is also adsorbed  at low
values onto fine sand, implying  that it would be highly mobile in soils and could leach  rapidly to
groundwaters.
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Bis (2-chloroethyl) Ether Fate/Treatment--
       Bis (2-chloroethyl) ether (BCEE) may degrade in soils, but acclimation may be necessary
(Howard  1989). The volatilization half-life of BCEE in streams was estimated to be about 4 days, while
the volatilization half-life of BCEE in lakes was estimated to be about 180 days. Photolysis is not
expected to be important, but biodegradation can reduce BCEE concentrations by 50 percent over 35
days. After acclimation, only 9 days were required to remove 50 percent of the BCEE by biodegradation.
Conventional water treatment removed about 80 percent of the BCEE, while activated carbon, when
added to conventional water treatment processes, removed all of the BCEE (Verschueren 1983).

Bis (2-chloroisopropyl) Ether

Bis (2-chloroisopropyl) Ether Filtered Fraction-
       The solubility of bis (2-chloroisopropyl) ether (BCIE) was reported to be 1700 mg/L (Verschueren
1983). No concentrations greater than the detection limit of about 1 ng/L were found by Pitt and Barren
(1990) in filtered stormwater samples.

Bis (2-chloroisopropyl) Ether Fate/Treatment-
       Basu and Bosch (1982), in their summary of the literature concerning bis (2-chloroisopropyl)
ether (BCIE), reported that hydrolysis is probably its most significant transformation process in aquatic
systems. The overall half-life of BCIE was estimated to vary between 3 and 30 days in rivers and 30 to
300 days in lakes and groundwaters. The evaporation half-life in surface waters was estimated to be
similar to the hydrolysis half-life. Leaching of BCIE is expected to be important in soils. They also
reported that BCIE is unlikely to be significantly sorbed by  plants.

        Activated carbon treatment of contaminated water resulted in almost complete removal of BCIE.
Conventional water treatment reduced the BCIE water content from 24 ng/L to below detection limits
(Verschueren 1983).

1,3-Dichlorobenzene

1,3-Dichlorobenzene Filtered Fraction and Sorption-
       The observed median filterable portion of 1,3-DCB (3 to 47 ng/L) found by Pitt and Barren (1990)
in stormwater was about 75 percent of the unfiltered sample concentrations. The solubility of 1,3-DCB is
about 125 mg/L (Verschueren 1983). 1,3-DCB may be moderately to tightly adsorbed to soils, but
leaching can occur (Howard 1989).

1,3-Dichlorobenzene Fate/Treatment--
       Bacterial degradation disturbed the chemical ring structure of 1,3-Dichlorobenzene (1,3-DCB)
within 96 hours (Verschueren 1983).  Neal and Basu (1982) reported that biotransformation is the most
significant transformation process, with a half-life of about  580 days in a river system. Sedimentation and
volatilization processes decrease 1,3-DCB concentrations  in half over about 1.5 days in rivers and 50
days in lakes. Biodegradation under aerobic conditions and volatilization from soil may be important
(Howard 1989).  Adsorption of 1,3-DCB to sediment is a major environmental fate mechanism. 1,3-DCB
is also quite volatile from water, with  a half-life of about 4 hours in moderately turbulent streams. It may
biodegrade under aerobic conditions  in water, but is not expected to degrade under anaerobic conditions
(such as in polluted sediments). Hydrolysis, oxidation, and  direct photolysis are not expected to be
important fate mechanisms of 1,3-DCB in the aquatic environment.

Summary

       Most of the organics and metals are associated with the non-filterable (suspended solids) fraction
of the wastewaters during wet weather. An exception was for stormwater zinc, fluoranthene, pyrene, and
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 1,3-dichlorobenzene, which were found mostly (>50%) in the filtered sample portions. Dry-weather
 wastewater flows tended to be much more associated with dissolved sample fractions.

        Many processes will affect these pollutants. Sedimentation is the most common fate and control
 mechanism for paniculate related pollutants. This would be common for most stormwater pollutants.
 Exceptions include the four stormwater constituents noted above which were mostly associated with the
 filterable sample portions.  Particulate removal can occur in  many control processes, including
 catchbasins, screens, drainage systems,  and detention ponds. These control processes allow removal of
 the accumulated polluted sediment for final disposal in an appropriate manner.

        Tables 34 and 35  summarize the likely fate mechanisms for these compounds (Callahan, et al.
 1979).  Biological or chemical degradation of the toxicants may occur, but is quite slow for many of the
 pollutants in anaerobic environments. Degradation of the soluble pollutants in the water column may
 occur,  especially when near the surface in aerated waters. Volatilization is also a mechanism that may
 affect many of the detected organic toxicants. Increased turbulence and oxygen supplies would
 encourage these processes that may significantly reduce pollutant concentrations. Sorption of pollutants
 onto solids and metal precipitation increases the sedimentation potential of the pollutants and also
 encourages more efficient bonding of the pollutants in soils, preventing their leaching to groundwaters.


 OUTFALL PRETREATMENT OPTIONS BEFORE STORMWATER INFILTRATION

 Sedimentation Treatment

 Wet Detention Ponds--
        Detention ponds are probably the most common management practice for the control of
 stormwater runoff. If properly designed, constructed, and maintained, wet detention ponds can be very
 effective in controlling a wide range of pollutants and peak runoff flow rates.

        There are many kinds of detention ponds, including dry ponds (which typically contain no water
 between storms), wet ponds (which contain standing water between storms), and combination ponds
 (which  drain slowly after storms and  may contain a small permanent pool). In a partial survey of cities in
 the U.S. and Canada, the American Public Works Association found more than 2,000 wet ponds (about
 half of which were publicly owned), more than 6,000 dry ponds, more than 3,000 parking lot multi-use
 detention areas, and more than 500 rooftop storage facilities (Smith 1982).

        In selected areas of the U.S., detention ponds have been required for some time and are
 therefore much more numerous than elsewhere. In Montgomery County, Maryland, as an example,
 detention ponds were first  required in 1971, with more than  100 facilities planned during that first year,
 and about 50 actually constructed. By 1978, more than 500 detention facilities had been constructed in
 Montgomery County alone (Williams  1982). In DuPage County, Illinois, near Chicago, more than 900
 stormwater detention facilities (some natural) receive urban runoff (McComas and Sefton 1985).

        The Nationwide Urban Runoff Program (NURP) included full-scale monitoring of nine wet
 detention ponds (EPA 1983). The Lansing, Michigan, project included two greatly enlarged pipe sections
 within the storm sewerage system (up-sized pipes) plus a larger detention pond. The project located in
 Glen Ellyn (west of Chicago) monitored a small lake, the largest detention pond monitored during the
 NURP  program. Ann Arbor, Michigan, monitoring included three detention ponds; Long Island, New York,
 studied one pond; the Washington, D.C. project included one pond. About  150 storm events were
 completely monitored at these ponds, and long-term performances ranged from negative removals for
the smallest up-sized pipe  installation to more than 90 percent removal of suspended solids at the largest
wet ponds. The best ponds reported BOD5 and COD removals of about 70 percent, nutrient removals of
about 60 to 70 percent, and heavy metal removals of about 60 to 95 percent.
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TABLE 34. IMPORTANCE OF ENVIRONMENTAL PROCESSES FOR THE AQUATIC FATES OF VARIOUS POLYCYCLIC AROMATIC HYDROCARBONS AND PHTHALATE ESTERS
Environmental
Process (1)
Anthracene
Ruoranthene
Phenanthrene
Diethvl Phthalate
(PEP)
Dl-n-butvl Phthalate
D8P)
Bis (2-ethvl-hexyn
Phlhalate (DEHP)
Butvl Benzvl
Phthalate
Volatilization
Sorption
 SO;
 accumulation
dissolved
portion may
undergo rapid
photolysis
maybe
competitive
with
adsorption
adsorbs onto
suspended
solids; move-
ment by sus-
pended solids
is important
transport
process
short-term
process, is
readily
metabolized
readily
metabolized
by organisms;
biodegrad-
ation probably
ultimate late
mechanism
dissolved
portion may
undergo rapid
photolysis
maybe
competitive
with
adsorption
adsorbs onto
suspended
solids; move-
ment by sus-
pended solids
is important
transport
process
short-term
process, Is
readily
metabolized
readily
metabolized
by organisms;
biodegrad-
ation probably
ultimate fate
mechanism
dissolved
portion may
undergo rapid
photolysis
maybe
competitive
with
adsorption
sor bed onto
suspended
solids; move-
ment by sus-
pended solids
is important
transport
process
short-term
process, Is
readily
metabolized
readily
metabolized
by organisms;
biodegrad-
ation probably
ultimate fate
mechanism
not important
not important

sorbedonto
suspended solids
and biota; complexa-
tion with humic
substances most
Important transport
process

variety of organisms
accumulate phthalates
(lipophilic)
can be metabolized


 (1) Oxidation and hydrolysis are not Important fate mechanisms for any of these compounds.

 Source: Callahan, et al. 1979
                                                                                                not important
                                                                              not important
                                                                              variety of organisms
                                                                              accumulate phthalates
                                                                              (lipophilic)
                                                                                                can be metabolized
                                                                                                       not important
                                                                                       not important
                                                                                                                 not important
                                                                                               not important
sorbedonto
suspended solids
and biota; complexa-
tion with humic
substances most
important transport
process
sorbed onto
suspended solids
and biota; complexa-
'tion with humic
substances most
important transport
process
sorbedonto
suspended solids
and biota; complexa-
tion with humic
substances most
important transport
process
                                                                                       variety of organisms
                                                                                       accumulate phthalates
                                                                                       (lipophilic)
                                                                                                                         can be metabolized
                                                                                               variety of organisms
                                                                                               accumulate phthalates
                                                                                               (lipophilic)
                                                                                                                                                    can be metabolized

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Environmental
Process (1)
TABLE 35.  IMPORTANCE OF ENVIRONMENTAL PROCESSES FOR THE AQUATIC FATES OF VARIOUS PHENOLS AND PYRENE

          Phenol                      Pentacholorphenol           2.4.6 -                      2,4 • dimethyl                Pyrene
Oxidation
Volatilization
Bio-
accumulation
Bio-
transformation
         photooxidation may
         be Important in
         degradation process
         in aerated, clear,
         surface waters

         metal -catalyzed
         oxidation may be
         important in aerated
         surface waters

         possibility of some
         phenol passing into
         the atmosphere

         not important
         not important
         very significant
Pentacholorphenol
(PCP)

reported to occur in
natural waters;
important near water
surface
                                               not important
not important
                                               sorbed by organic
                                               litter in soil and
                                               sediments
bioaccumulates in
numerous aquatic
organisms
can be metabolized
to other phenol
forms
2.4.6 -
Trichlorophenol

reported, but
importance is
uncertain
                            not important
not important
                            potentially important
                            for organic material,
                            not important for
                            clays
not important
reported in soil and
sewage sludge;
uncertain for natural
surface waters
2,4 • dimethyl
phenol (2,4-xvlenol)

may be important
degradation process
in clear aerated
surface waters
metal-catalyzed
oxidation may be
important in aerated
surface waters

not important
                            not Important
not important
inconclusive
information
                                                                                                                                 dlssoh/ed portion may
                                                                                                                                 undergo rapid
                                                                                                                                 photolysis
                                                       not important
                                                                                                                                 not as important
                                                                                                                                 as adsorption
adsorption onto
suspended solids
important; movement
by suspended solids
important

short-term process
not significant;
metabolized over
long term

readily metabolized;
biodegradation
probably ultimate
fate process
(1) Hydrolysis is not an important fate mechanism for any of these compounds.

Source: Callahan, et al. 1979

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       The Lansing NURP project monitored a wet detention pond (Luzkow et al. 1981). The monitored
pond was located on a golf course that received urban runoff from an adjacent residential and
commercial area. Suspended solids removals were about 70 percent for moderate rains (0.4 to 1-inch
rains) while phosphorus removals were usually greater than 50 percent. Total Kjeldahl nitrogen removals
ranged from about 30 to 50 percent.

       Two wet detention ponds near Toronto, Ontario, were monitored from 1977 through 1979
(Brydges and Robinson 1980). Lake Aquitaine is 4.7 acres in size and receives runoff from a 107-acre
urban watershed. Observed pollutant reductions were about 70 to 90 percent for suspended solids, 25 to
60 percent for nitrogen, and about 80 percent for phosphorus. The much smaller Lake Wabukayne (2
acres) received runoff from a much larger urban area (466 acres). Lake Wabukayne experienced much
smaller pollutant reductions: about 30 percent for suspended solids, less than 25 percent for nitrogen,
and 10 to 30 percent for phosphorus.

       Oliver, et al. (1981) monitored a small lake detention facility in Rolla, Missouri. Suspended solids
yield reductions averaged about 88 percent, with 54 and 60 percent yield reductions for COD and total
phosphorus. Organic nitrogen yields were reduced by about 22  percent.

       Gietz (1983) studied a 3.3-acre wet detention pond serving a 150-acre urban watershed near
Ottawa, Ontario. He compared batch operation (which retains water in the pond without discharge as
long as possible) with normal, continuous operation (which has  variable but continuous discharges).
Batch operation of the pond resulted in substantial pollutant control improvements for particulate solids,
bacteria,  phosphorus, and nitrate nitrogen. Continuous operation gave slightly better performance for
BODs and organic nitrogen. Particulate solid reductions were about 80 to 95 percent, 6005 reductions
were about 35 to 45 percent, bacteria was reduced by about 50 to 95 percent, phosphorus by about 70 to
85 percent, and organic nitrogen by about 45 to 50 percent.

       Yousef (1986)  reported long-term nutrient removal information for a wet detention pond in
Florida having substantial algal  and rooted aquatic plant growths. He found 80 to 90 percent removals of
soluble nutrients due to plant uptake. Particulate nutrient removals, however, were quite poor (about ten
percent).

Catchbasin, Sewerage, and Street Cleaning-
       The mobility of catchbasin sediments was investigated  by Pitt (1979) during a research project
sponsored by the U.S.  EPA's Storm  and Combined Sewer Section. This project used particulate
fluorescent tracers mixed with catchbasin sediment. It was concluded that the amount of catchbasin  and
sewerage sediment was very large in comparison with storm runoff yields,  but was not very mobile.
Cleaning the material from catchbasins would reduce the  potential of very large discharges during rare
scouring  rains.

       Further research was conducted in Bellevue, Washington, (Pitt 1984) to investigate the
accumulation  rate of sediment in storm sewerage and the effects of sewerage cleaning on runoff
discharges. The main source of the sediment in the catchbasins and the sewerage was found to be the
street surfaces. The catchbasin and sewerage sediment consisted of the largest particles that were
washed from the streets. Smaller particles that had washed from the streets during rains had proceeded
into receiving  waters, leaving behind the larger particles. A few  unusual locations were dominated by
erosion sediment originating from steep hillsides adjacent to the storm sewer inlets.

       Catchbasin sump particulates can be conveniently removed to eliminate this potential source of
urban runoff pollutants. Cleaning catchbasins twice a year was  found to allow the catchbasins to partially
capture particulates for most rains. This cleaning schedule was found to reduce the total solids and lead
urban runoff yields by between 10 and 25 percent, and COD, total Kjeldahl nitrogen, total phosphorus,
and zinc by between 5  and  10 percent (Pitt 1984 and Pitt and Shawley 1981).
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        Street cleaning effectiveness has been monitored at many locations and shows mixed results in
removing toxicants from stormwater (Pitt 1979, Pitt and Shawley 1981, Bannerman, et al. 1983, and Pitt
1984, for example). Street cleaning has been shown to be very effective in removing the largest
participates on streets (especially those greater than about 200 microns). Unfortunately, street cleaning
generally  removes only a very small fraction of the small particles that are readily washed-off streets by
rains (Pitt 1987). Many of the street cleaning demonstration projects monitored a wide variety of
available street cleaning equipment types, including mechanical broom sweepers, vacuum cleaners, and
regenerative-air cleaners. Pitt (1984) also monitored a special prototype regenerative-air cleaner
specifically modified to increase the  removal of small particles. Many types of cleaner operations were
investigated in some of these projects, including multiple passes using broom sweepers followed by
vacuum cleaners, cleaning frequencies as often as two passes per day, full-street-width street cleaning,
etc. Many demonstration projects only monitored relatively small changes in the street cleaning
programs, however, and dramatic results could not have been expected. In arid areas of the west, Pitt
(1979) and Pitt and Shawley (1981) found that street cleaning could be beneficial in improving the
stormwater quality associated with early fall  rains following long dry summers. The dry summers allowed
very large street dirt loadings to accumulate (if no street cleaning was used). If frequent street cleaning
was used in the late summer (about  weekly cleaning during  September and October, for example),
moderate heavy metal removals (25 to 50%) from the stormwater are likely. In most areas of the U.S.,
frequent rains would be more successful in keeping the streets clean than  intensive street cleaning (Pitt
1984), resulting in very limited benefits. Street runoff has also  been over-emphasized as a source of
runoff pollutants for many areas. In most locations, streets contribute only a small portion of the total
annual runoff loading, even though they are very important pollutant sources for the smallest rains (Pitt
1987). Therefore,  even absolute cleanliness of streets would only result in limited overall stormwater
quality improvement. In general,  recommended street cleaning programs (cleaning about every three
months in residential and commercial areas, and monthly in industrial areas, intensive spring cleaning
after snowmelt in northern areas, rapid leaf removal in the fall, and intensive late summer cleaning in the
arid west) using any type of street cleaning equipment available would result in optimal, but limited,
stormwater quality improvements. Other stormwater control  options are usually found to be more cost-
effective in removing pollutants from stormwater than street cleaning (Pitt  1986).

Fate Mechanisms in Sedimentation Devices-
       The major fate mechanism in wet detention ponds and in smaller sumps, such as catchbasins, is
sedimentation. Pollutants mostly associated with particulate matter will  be much better removed than
pollutants mostly in filterable forms. Unfortunately, sedimentation can result in the development of
polluted sediments. These sediments can be anaerobic, with associated chemical and biochemical
transformations. Resulting toxic chemical  releases from heavily polluted sediments, plus the potential
problems associated with the disposal of toxicant contaminated dredging spoils during required
maintenance, can present problems.

       Other important fate mechanisms available in wet detention ponds, but which are probably not
important in small sump devices, include volatilization and photolysis. Biodegradation, biotransformation,
and bioaccumulation (into plants and animals)  may also occur in ponds. Most wet detention ponds are
completely flushed by moderate rains (probably every several  weeks), depending on their design. Much
of the runoff during moderate and large rains passes through the ponds during several hours during  and
immediately after rains. Sediments may reside in ponds for  several to many years. Therefore, the time
available for these other removal or transformation processes  can vary greatly for detention ponds. The
residence time in small sedimentation  devices is just a few minutes and significant biological activity
may not be present, except in the anaerobic sediments in catchbasin sumps and in the culverts of
sewerage.

       Most sedimentation devices  (especially ponds) are designed to provide effective sedimentation
and sufficient  sacrificial storage for the long-term maintenance of accumulated sediment. The removal of
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many toxicants by other processes can possibly be increased by aerating the water and increasing the
associated oxygen content and biological activity in ponds.


LOCAL PRETREATMENT OPTIONS BEFORE SOURCE AREA STORMWATER INFILTRATION

Biofiltration Devices

General Infiltration-
       All infiltration devices redirect surface runoff waters to the groundwater. They are recharge
devices that can be used at many local areas in a watershed area. They must be carefully designed,
especially using appropriate pretreatment as needed, to enable long-term operation and to protect
groundwater quality.

       Upland infiltration devices (such as infiltration trenches, porous pavements, percolation ponds,
and grass roadside drainage swales) are located at urban source areas. Infiltration (percolation) ponds
are usually located at stormwater outfalls, or at large paved areas. These ponds, along with perforated
storm sewerage, can infiltrate flows and pollutants from all upland sources combined.

       Several Nationwide Urban Runoff Program projects investigated infiltration devices (EPA 1983).
They found that infiltration devices can safely deliver large fractions of the surface flows to groundwater,
if carefully designed and located. Local conditions that can make localized stormwater  infiltration
inappropriate include steep slopes, slowly percolating soils, high groundwater, and nearby important
groundwater uses.

       The Lake Tahoe (California/Nevada) Regional Planning Agency has developed a set of design
guidelines for infiltration devices in an area that has severe winters (Lake Tahoe 1978). They
recommend the use of infiltration trenches to collect and infiltrate runoff from impervious surfaces, such
as driveways, roofs, and parking lots. The Ontario Ministry of the Environment (1984) also included
infiltration devices in its general stormwater management plan. The states of Florida, Maryland, and
Delaware all extensively use infiltration as an important stormwater management and to recharge
shallow groundwaters adversely affected by development.

       The Long Island, New York, and metropolitan Washington, D.C. NURP projects (EPA 1983)
examined the performance of several types of infiltration devices. The Long Island project studied a
series of interconnected percolating catchbasins, which were found to recharge more than 99 percent of
the stormwater discharges. The Washington, D.C. study found that porous pavement recharged 85 to 95
percent of the pavement runoff flows, while an infiltration trench recharged about 50 percent of the
surface flows. The EPA (1983) concluded that, with a reasonable degree of site-specific design
considerations to compensate for soil characteristics, infiltration devices can be very effective in
controlling urban runoff through recharging groundwaters.

Grass Filter Strips-
       Grass filter strips may be quite effective in removing particulate pollutants from overland flows.
The filtering effects of grasses, along with increased infiltration/recharge, reduce the particulate sediment
load from urban landscaped areas. Filter strips are extensively used in contour strip cropping systems in
agricultural areas to reduce erosion yields associated with grain crop production. Grass filters can be
used at urban runoff source areas to reduce the particulate pollutant yields to the storm drainage system.
Specific situations may include directing roof runoff to grassed areas instead of pavement, planting grass
between eroding slopes and the storm drainage system, and planting grass between paved or unpaved
parking or storage areas and the drainage system.

       Novotny and Chesters (1981) reviewed several publications describing research on the
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effectiveness of grass filter strips. Grass filtering occurs during shallow flows, requiring the depth of flow
to be less than the vegetation height. The critical length is defined as the minimum water flow length
within which almost 100 percent of the particles of concern are removed. This length (and removal
efficiency) varies for different particle sizes, grass density, flow depth and flow velocity. For Bermuda
grass, the critical length was found to be about 10 feet for sand, about 50 feet for silt, and about 400 feet
for clay (Wilson 1967).

Grass Swales-
        Grass swale drainages are a type of infiltration device and can be used in place of concrete curb
and gutter drainages in most land uses, except possibly strip commercial and high density residential
areas. Grass swales allow the recharge of significant amounts of surface flows.

        Several large-scale urban runoff monitoring programs have included test sites that were drained
by grass swales. Bannerman, et al. (1979), as part of the International Joint Commission  (IJC) monitoring
program to characterize urban runoff inputs to the Great Lakes, monitored a residential area served by
swales and a similar residential area served by concrete curb and gutters in the Menomonee River
watershed in the Milwaukee area. This monitoring program included extensive flow and pollutant
concentration measurements during a variety of rains. They found that the swale-drained area, even
though it had soils characterized as poorly drained, had significantly lower surface flows (up to 95
percent lower) compared to the curb and gutter area.

        The ability of grass swales to infiltrate source area sheetflows was also monitored in Durham,
New Hampshire (EPA 1983). A special swale was constructed to treat runoff from a commercial parking
lot. Flow measurements were not available to directly measure infiltration, but significant  pollutant
concentration reductions were found, apparently due to filtration. Soluble and particulate heavy metal
(copper, lead, zinc, and cadmium) concentrations were reduced by about 50 percent. COD, nitrate
nitrogen, and ammonia nitrogen concentrations were reduced by about 25 percent, while  no significant
concentration reductions were found for organic nitrogen, phosphorus, and bacteria.

        Wang, et al. (1980) monitored the effectiveness of grass swales  at several freeway sites in the
State of Washington. Lead was more consistently and effectively trapped in the swale soils than the
other metals, possibly because of its greater association with  particulates in the runoff. Particulate
filtering was therefore an important process during these tests. Lead concentrations were typically
reduced by 80 percent or more, while copper was reduced by about 60 percent, and zinc by about 70
percent. Because of the particulate filtering action, they concluded that it may be necessary to remove
the contaminated soils and replant the grass periodically to prevent dislodging the deposited polluted
sediment. Part of the swales monitored by Wang, et al. (1980) were bare earth lined. Pollutant
concentrations were not found to be effectively reduced in these sections, and the earth lining was not
contaminated.

        A project to specifically study the effects of grass swale drainages was also  conducted in Brevard
County, Florida, by Kercher, et al. (1983). Two adjacent low density residential areas, with about 14
acres and 50 homes each, were selected for study. One area had conventional concrete curbs and
gutters,  while the other had grass swales for roadside drainage. The two  areas had very similar
characteristics (soils, percentage imperviousness, slopes, vegetation, etc.). Thirteen storm events were
monitored in the areas for flow and several selected pollutants. The curb and gutter  area produced  runoff
flows during all 13 events, while the grass swale area produced runoff during only three events. The
grass swale system also cost about one-half as much as the curb and gutter system.

        In another large-scale urban runoff monitoring project, Pitt and McLean (1985) monitored a
residential area in Toronto that was served about evenly by swales and concrete curbs and gutters. The
pollutant concentrations in both types of drainage systems were similar, but the area had  annual flows
about 25 percent less than if the area were served solely by curbs and gutters. For small but frequent
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rains (less than about 0.5 inch), very little surface runoff was observed, with almost all of the flows being
infiltrated to the groundwater.

Porous Pavements-
       Porous pavement is a "hard" surface that can support a certain amount of activity, while still
allowing water to pass through to recharge the underlying groundwaters. Porous pavement is generally
used in areas of low traffic, such as service roads, storage areas, and parking lots. Several different
types of porous pavement exist. Open mixes of asphalt appear similar to regular asphalt, but use only a
specific size range of rocks in the hot mix. The porosity of the finished asphalt is much higher than
regular asphalt, if properly designed and constructed. Concrete grids have open holes up to several
inches wide with sand or gravel in the holes. It is possible to plant grass in the holes, if traffic is very light
and  if light and moisture conditions  are adequate. They can  be designed to recharge all of the  runoff
water from paved areas. The percolation rate of the pavement base is usually the limiting condition in
porous pavement installations (Cedergren 1974).

       Porous pavements do not provide any direct water quality treatment for the infiltrating water,  but
they do allow the water to pass through  soil before reaching  the groundwater. The organic content of the
soil and associated sorption capacity of  the soils may be limited below porous pavements because of the
pavement construction operations.

       Porous pavements may be effectively used in areas having soils with adequate percolation
characteristics, rf carefully designed and maintained. The percolation requirements for porous pavements
are not as demanding as they are for other infiltration devices, unless runoff from other areas is directed
towards the paved area. The percolation of the soils underlying the porous pavement installation need
only to exceed the rain intensity directly. In  most cases, several inches of storage is available in the
asphalt base to absorb short periods of very high rain intensities. Diniz (1980) states that the entire area
contributing to the porous pavement can be removed from the surface hydrologic regime (and  therefore
be used for groundwater recharge).

       Gburek and Urban (1983) studied a porous pavement parking lot in Pennsylvania. They found
that  percolation below the pavement occurred soon after the start of rain. For small rains (less than 0.25
inches), no percolation under the pavement was observed, with all of the rain being contained in the
pavement base. Percolation during  large rains was equal to  about 70 to 90 percent of the rainfall. The
differences between the rain amounts and the observed percolation quantities were caused by flash
evaporation (not estimated) and storage in the asphalt base material.

       Goforth et al. (1983 and 1984) evaluated a porous pavement parking lot in Austin, Texas, over
several years and under heavy traffic conditions. Infiltration rates through the pavement averaged about
1800 inches per hour, while the two-inch pavement base had an infiltration rate of about 70,000 inches
per hour. Day  (1980) conducted a series of laboratory tests using several different types of concrete grid
pavements. The geometry of the grid was more important than the percentage of open space in
determining the ability of the grid to absorb  and detain rainwater. The runoff coefficients from the grids
ranged from 0.06 to 0.26 (resulting in recharge rates from 75 to 95 percent) depending on the rain
intensity, ground slope, and subsoil type.

Fate Mechanisms in Biofiltration Devices-
       Sorption of pollutants to soils is  probably the most important fate mechanism of toxicants in
biofiltration devices. Many of the devices also use sedimentation and filtration to remove the particulate
forms of the pollutants from the water. Incorporation of the pollutants onto soil with subsequent
biodegradation and minimal leaching to  the groundwater is desired. Volatilization, photolysis,
biotransformation, and bioconcentration  may also be important in grass filter strips and grass swales.
Underground french drains and porous pavements offer little biological activity to reduce toxicants.
                                              101

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                                            110

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                                            115

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                                        APPENDIX A

              ANNOTATED BIBLIOGRAPHY OF GROUNDWATER CONTAMINATION
       A bibliography of all of the literature sources used in the preparation of Section 3 of this report
(Potential Contamination Associated with Urban Runoff) was prepared and is included in this appendix.
This bibliography includes both the information needed to locate the reference and an abstract. A matrix
of information (Table A-1) was also prepared.  This matrix references the author and the date of the
reference in the same format that is used in the report.  The matrix also notes the source water
considered in the reference, the location of the research (where applicable), and the contaminants
discussed. The contaminants are organized in the same manner as in Section 3: Nutrients, Pesticides,
Organics, Pathogens, Metals, Dissolved Solids, Suspended Solids and Dissolved Oxygen.  If a
contaminant was addressed in the reference, an "X" is placed in the appropriate column on the matrix.
                                            116

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                                                        TABLE A.1  GROUNDWATER CONTAMINATION REFERENCES
                                      Source
Author (Date)                           Water

AJhajJar, et al. (1990)                   Agriculture
Amer. Water Works Assoc. (1990)       Agriculture
Amoros, et al. (1969)                   Agriculture
Armstrong and Uena (1992)             Stormwater
Aronson and Seaburn (1974)            Stormwater
Asano (1987)                          Sanitary
Bao-rui(1988)                         Sanitary
Earradough (1966)                     Industrial
Boggess (1975)                        Industrial
Bouchard (1992)                        Sanitary
Bouwer, et al. (1984)                    Sanitary
Bouwer (1989)                        Agriculture
Bouwer (1987)                        Agriculture
Bouwer and Idelovteh (1987)             Sanitary
Brown (1962)                          Sanitary
Butler (1987)                          Stormwater
Cavanaugh, et al. (1992)                 Sanitary
Chang, et al. (1988)                     Sanitary
Chase (1987)                          Sanitary
Cisic(1992)                           Sanitary
dose (1987)                          Agriculture
Clothier and Sauer (1968)              Agriculture
Oaun(1979)                          Sanitary
Crites(1985)                           Sanitary
Crook, etal. (1990)                     Sanitary
Deason(1989)                        Agriculture
Deason (1987)                        Agriculture
DeBoer(1983)                         Sanitary
Domagalski and Dubrovsky (1992)       Agriculture
Ehrlich, etal.  (1979a)                   Industrial
Ehriich, et al.  (1979b)                   Sanitary
Bder, et ai. (1985)                      Sanitary
Eren                                  Sanitary
         Location
         Of Work
         Nebraska
          Spain
        Wisconsin
   Long Island, New York
         California
          China
Escam. & Santa Rosa Co., FL
     Lee County, Florida
  Santa Monica, California
      Phoenix, Arizona
      Arizona & Israel
   Tarpon Springs, Florida
       Austin, Texas
       North Carolina
     Riverside, California
      Phoenix, Arizona
   Los Angeles, California
         California
     CA & Western US
    West & Midwest US

   San Joaquin Valley, CA
     Pensacola, Florida
     Bay Park, New York
    Tallahassee, Florida
           Israel
                                                         Dissolved   Suspended   Dissolved
Nutrients   Pesticides   Organics   Pathogens    Metals      Solids       Solids      Oxygen
   X
   X
   X
   X
   X
   X
   X
                                 X
                                 X
                                 X
                                 X
                                 X
    X
    X
X
X
X
X
X
               X
               X
               X

               X

               X
            X
            X
            X
            X
            X
                                      X
                                      X
X
X
X
X
           X

           X



           X

           X

           X
X
X
X
X
X
                                  X
                                  X
                                  X
                                                            X
                                                            X
           X
           X
           X
           X
                      X
                      X
                      X

                      X
                                                          X

                                                          X
                                                          X

                                                          X
                                               X
                                               X
X
X
                       X
                       X
                       X
                                    X
                                    X
                                                                                                                                                             (continued)

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                                                                          TABLE A.1  (CONTINUED)
                                       Source
Author (Date)                           Water

Ferguson (1990)                      Stormwater
Ferguson, et al. (1990)                 Agriculture
Gerba and Goyal (1985)                  Sanitary
Gerba and Haas (1988)                  Sanitary
German (1989)                       Stormwater
Goldschmid (1974)                      Sanitary
Goolsby(1972)                        Industrial
Greene (1992)                        Stormwater
Hampson (1966)                      Stormwater
Harper (1988)                         Stormwater
Hckey(1984)                           Sanitary
Hlckey and Vecchloll (1986)             Industrial
Kckey and Wilson (1982)              Stormwater
Kgglns(1984)                          Sanitary
Horsley and Moser (1990)              Stormwater
Hull and Yurewicz (1979)               Stormwater
Ishizakl (1985)                        Stormwater
Jansons, et al. (1989a)                   Sanitary
Jansons, etal. (1989b)                   Sanitary
Johnson (1987)                         Sanitary
Karkal (1992)                           Sanitary
Katapodes and Tang (1990)            Agriculture
Kaufman (1973)                         Sanitary
Knisel and Leonard (1989)              Agriculture
Krawchuk and Webster (1987)          Agriculture
Ku and Simmons (1986)                Stormwater
Ku, etal.  (1992)                       Stormwater
Ku, et al.  (1975)                         Sanitary
Lauer(1988a)                         Agriculture
Lauer(1988b)                         Agriculture
Lee (1990)                            Agriculture
Uoyd, et al. (1988)                     Stormwater
Loh, et al. (1988)                         Sanitary
Malik, et al. (1992)                     Stormwater
        Location
        Of Work

        Georgia
        Nebraska
     Orlando, Florida
         Israel

 Santa Monica, California
   Jacksonville, Florida
         Florida
  SL Petersburg, Florida
         Florida
    Mulberry, Florida
       New Jersey
     Massachusetts
    Live Oak, Florida
         Japan
    Tucson, Arizona
 Orange Grove, California

         Florida
        Georgia
    Manitoba, Canada
  Long Island, New York
Nassau County, New York
   Bay Park, New York
 Patterson & Prosser, WA
 Patterson & Prosser, WA

    United Kingdom
         Hawaii
 Central Coast, California
Nutrients   Pesticides   Organlcs   Pathogens    Metals
                                         Dissolved   Suspended   Dissolved
                                           Solids       Solids       Oxygen
X
X
X

X
X


X
X
X
X


X
X




X
X
X

X
X
X
X
X
X


X
   X
   X
   X
   X
   X
   X
   X
X
X
X
           X
           X
           X
                                     X
                                     X
                                     X
                                                                  X
                                                                  X
X
X
                                                 X
                                                 X
                                                 X
                                                 X

                                                 X
X
X
                                  X
                                  X
                                                            X
                                                            X

                                                            X
                                                            X
X
X
X
                       X
                       X
                                                         X
                                                         X
X
X
                                               X
                                               X
X

X


X

X


X

X
                                                                                                                                                              (continued)

-------
                                                                           TABLE A.1  (CONTINUED)
                                       Source
Author (Date)                           Water

Mancini and Plummer (1992)           Stormwater
Markwood (1979)                        Sanitary
Marton and Mohler (1988)              Stormwater
Marzouk, et al. (1979)                    Sanitary
Merkel, et al. (1988)                    Stormwater
Mossbarger and Yost (1990)            Agriculture
Nellor, et al. (1985)                      Sanitary
Nightingale, et al. (1983)                Agriculture
Nightingale (1987a)                    Stormwater
Nightingale (1987b)                    Stormwater
Nightingale and Banchi (1977a)         Agriculture
Nightingale and Bianchi (1977b)         Agriculture
Norberg-King, et al. (1991)             Agriculture
Pahren(1985)                          Sanitary
Peterson (1988)                       Agriculture
Petrovic (1990)                        Stor mwater
Phelps(1987)                           Sanitary
Rerce and Wong (1988)               Agriculture
Pitt (1974)                              Sanitary
Pfttetal. (1975)                        Sanitary
Power and Schepers (1989)            Agriculture
Pruitt, et al. (1985)                       Sanitary
Ragone (1977)                          Sanitary
Ragone, et al. (1975)                    Sanitary
Ragone and Vecchioli (1975)             Sanitary
Ramsey, et al. (1987)                    Sanitary
Razack, et al. (1988)                  Stormwater
Rea and Istok (1987)                  Agriculture
Reichenbaugh (1977)                  Agriculture
Reichenbaugh, etal. (1979)              Sanitary
Rein, et al. (1992)                       Sanitary
Rice, et al. (1991)                     Agriculture
         Location
         Of Work
      Czechoslovakia
          Israel
         Germany
Corn Belt & Lake States, US
  Los Angeles County, CA
     Fresno, California
     Fresno, California
     Fresno, California
     Fresno, California
     Fresno, California
  Colusa Basin Drain, CA

         Wyoming

    Gainesville, Florida
         Canada
    Dade County, Florida
    Dade County, Florida

          Florida
    Bay Park. New York
    Bay Park, New York
    Bay Park, New York
      Lubbock, Texas
          France

     Lakeland, Florida
   St. Petersburg, Florida
Nutrients   Pesticides   Organlcs  Pathogens    Metals
   X
   X
   X
   X
    X
    X

    X
    X
    X
    X
    X
    X

    X
    X
    X
X
X
           X

           X

           X
X

X
                                     X

                                     X
                       X
                       X
                       X
                       X

                       X

                       X
                       X
                                          Dissolved   Suspended    Dissolved
                                            Solids       Solids      Oxygen
X
X
X
X

X
X
X

X
X
X


X

X

X
X
X
X

X
X
X



X
X
X
X
X
X
X
X
X
                                                                      X
                                                                      X
                                                                      X
                                                                                                                                                               (continued)

-------
                                                                            TABLE A. 1  (CONTINUED)
                                        Source
Author (Date)                            Water

Bitter, et at. (1989)                     Agriculture
Hitter, et al. (1991)                     Agriculture
Robinson and Snyder (1991)            Stormwater
Rosenshein and Mickey (1977)            Sanitary
Sabatini and Austin (1968)              Agriculture
Sabol, et al. (1987)                     Agriculture
Salo, et al. (1986)                      Stofmwater
Schiffer (1989)                        Stofmwater
Schmidt and Sherman (1987)            Agriculture
Schneider, etal. (1987)                  Sanitary
Seaburn and Aronson (1974)            Stormwater
Shirmohammadi and  Knisel (1989)       Agriculture
Smith and Myott (1975)                  Sanitary
Spalding  and  Kitchen (1988)            Agriculture
Squires, etal. (1989)                    Agriculture
Squires and Johnston (1989)            Agriculture
Steenhuis, etal. (1988)                  Agriculture
Strutynski, et al. (1992)                  Stofmwater
Tim and Mostaghimi (1991)               Sanitary
Townley, et al. (1992)                    Sanitary
Treweek  (1985)                         Sanitary
Troutman, et al. (1984)                   Industrial
US EPA (1992)                         General
Varuntanya and Shafer (1992)            Sanitary
Vaughn, et al. (1978)                     Sanitary
Vecchioli, et ai. (1984)                   Industrial
Verdin, et al. (1987)                     Sanitary
Waller, et al. (1987)                     Sanitary
Wanielista, et al. (1991)                 Stormwater
Wellings(1988)                         Sanitary
White and Dornbush (1988)              Sanitary
Wilson, et al. (1990)                    Stormwater
Wolff, et al. (198S)                      Sanitary
Yurewicz and Rosenau (1986)            Sanitary
        Location
        Of Work

  Northeast 4 East US
        Delaware
     South Carolina
Pinellas Peninsula, Florida

  Arizona & New Mexico
        California
         Florida
        California
  Long Island, New York
  Long Island, New York
     Southeast US
  Long Island, New York
        Nebraska
        California
   Cambria, California

   Pensacda, Florida
  Long Island, New York
    Pensacda, Florida
        Nevada
 Bfoward County, Florida
 Orange County, Ftarida

      South Dakota
  Pima County, Arizona
    Saxony, Germany
   Tallahassee, Florida
Nutrients   Pesticides  Organics   Pathogens

               X

               X
                                           Metals
X
X
X
X
   X
   X
   X
   X
   X
   X
   X
   X

   X
            X
            X
            X
            X
            X

            X
            X
   X
   X
            X

            X
X
X

X
X
                       X
                       X
                       X
X

X
                                                                   X
                                                                   X
                                     X
                                     X
X
X
                                                                              X
                                                                              X
X
X
X
                                                     Dissolved
                                                      Solids
X

X

X
X
X
X
                                          Suspended
                                            Solids
                                 Dissolved
                                  Oxygen
                                                            X
                                                            X
                                                            X

                                                            X
 X
 X

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Alhajjar, B. J., G. V. Slmslman and G. Chesters.  "Fate And Transport Of Alachlor, Metolachlor
And Atrazine In Large Columns."  Water Science And Technology:  A Journal Of The
International Association Of Water Pollution Research. V. 22, n. 6.  pp. 87-94. 1990.
       Abstract.   ^Q rjng.|abeled atrazine, alachlor, and metolachlor were surface-applied at 3.14 kg
a.i./ha in greenhouse lysimeters containing two soils in an ongoing experiment. Bromide (Br) -a
conservative tracer- at 6.93 kg/ha as KBr and nitrate-nitrogen (NO3-N) at 1 12 kg/ha as KNC>3 were
mixed with each herbicide and surface-applied.  Growth of Red top (Agrostis alba) was established in
each column (105 cm long and 29.4 cm i.d.). The experiment consisted of 12 columns (2 soils x 3
herbicides x 2 replicates) each fitted with four sampling ports for leachates, a volatilization chamber, and
an aeration and irrigation system. Volatile materials are being trapped directly in solvents. One column
replicate was dismantled for soil and plant analyses.  Columns of Plainfield sand and Piano silt loam
treated with alachlor and metolachlor were sampled after 23 and 28 weeks, respectively; the atrazine
columns after 35 weeks.  Herbicide residues are determined by liquid scintillation counting, extracted and
separated by thin-layer chromatography using autoradiographic detection.  Volatilization was £ 0.01% of
the amount of herbicide applied.  The order of herbicide mobility was alachlor > metolachlor » atrazine.
As many as 8 to 12 alachlor metabolites and 2 to 6 metolachlor metabolites were separated in leachates.
American Water Works Association.  "Fertilizer Contaminates Nebraska Groundwater."  AWWA
Mainstream. V. 34, n. 4. pp.6.  1990.

       Abstract.   Nitrates and  nitrogen from commercial fertilizers, manure, and other sources are
increasingly contaminating large areas of groundwater in Nebraska.  Nitrate was by far Nebraska's most
frequently encountered contaminant.  Most of the contamination stems from nonpoint sources such as
rainwater runoff and erosion, not from spills or other accidents.


Amoros, I., J. L. Alonso and I. Peris.  "Study Of Microbial Quality And Toxicity Of Effluents From
Two Treatment Plants Used For Irrigation."  Water Science And Technology: A Journal Of The
International Association On Water Pollution Research. V.  21, n. 3. pp. 243-246.  1989.

       Abstract.   The use of treated wastewater for agriculture is currently  practiced in many
countries.  The benefits of recycling wastewater are based upon its constituents, particularly nitrogen,
phosphorus and potassium,  which are of value as fertilizers for many crops. There are, however,
potential health risks associated with wastewater reuse. A number of bacterial pathogens excreted in the
faeces of humans and animals are found in wastewater.  The most significant pathogens, such as
enteropathogenic Escherichia coll, Salmonella, Shigella, Yersinia, Vibrio, Campylobacter and Leptospira,
can be transmitted via sewage-irrigated vegetables. Populations of  bacterial pathogens in wastewater
may be quite high, although  variable, and may depend on the effectiveness of wastewater treatment. In
addition, toxic substances, such as heavy metals and some organic  compounds, may be found.

       In the province of Alicante, there are some arid agricultural areas designated for grape
cultivation but which have water resource problems. The use of treated wastewater from secondary
treatment plants is one solution to this problem. Some reservoirs have been constructed to store
wastewater destined for irrigation.

       A study of the health risks associated with wastewater reuse (especially important since grapes
                                             121

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are destined for human consumption and are normally eaten raw, and not peeled) was carried out.  The
presence in water and on fruit of total conforms, faecal coliforms and faecal streptococci, and pathogens
such as Salmonella and Vibrio c/7o/erae(only in wastewater) was investigated. Total and faecal coliforms
and faecal streptococci were considered as indicator bacteria for the evaluation of the faecal pollution.
Salmonella species were investigated because they are one of the pathogenic organisms most
frequently found in sewage and they have been isolated from effluent samples after secondary treatment
and disinfection with chlorine dioxide and ozone.  V. cholerae is also transmitted via contaminated water
and some studies have reported prolonged survival of this micro-organism in sewage with increased
resistance to chlorine.  Microbial toxicity tests to detect the potential toxicity of the wastewaters were
conducted.
Armstrong, D. E. and R. Llena.  Stormwater Infiltration: Potential For Pollutant Removal. Project
Report To The U.S. Environmental Protection Agency. Wisconsin Department Of Natural
Resources, Water Chemistry Program. 1992.

       Abstract.   The potential mobility of pollutants during infiltration of urban stormwater through
soil was investigated. Groups of 32 organic and seven inorganic chemicals were evaluated.  The
framework for evaluating mobility was that of a conservative  (non-sorbed ) chemical. The main
parameter controlling relative leaching rate was the pollutant K^ for sorption by the soil.  For organic
chemicals, K^ values were calculated based on predicted sorption to soil organic and inorganic
components. Values were estimated for each compound in two  soils at three organic matter contents.
Soil organic  matter was the dominant component controlling K^, even in low organic matter soils.
Among compounds, K,j increased with increasing hydrophobicity (octanol-water partition coefficient).
For inorganic pollutants, published K
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Aronson, D. A. and G. E. Seaburn. Appraisal Of Operating Efficiency Of Recharge Basins On
Long Island, New York, In 1969. Geological Survey Water-Supply Paper 2001-D.  U.S. Government
Printing Office, Washington, D.C. 1974.

       Abstract.   Recharge basins on Long Island are unlined pits of various shapes and sizes
excavated in surficial deposits of mainly glacial origin.  Of the 2,124 recharge basins on Long Island in
1969, approximately 9 percent (194) contain water 5 or more days after a 1-inch rainfall. Basins on Long
Island contain water because (1) they intersect the regional water table  or a perched water table, (2) they
are excavated in material  of low hydraulic conductivity, (3) layers of sediment and debris of low hydraulic
conductivity accumulate on the basin floor, or (4) a combination of these factors exists.

       Data obtained as part of this study show that (1) 22 basins contain water because they interest
the regional water table, (2) a larger percentage of the basins excavated in the Harbor Hill and the
Ronkonkoma morainal deposits contain water than basins excavated in the outwash deposits, (3) a larger
percentage of basins that  drain industrial and commercial areas contain water than basins that drain
highways and residential areas, (4) storm runoff from commercial and industrial areas and highways
generally contains high concentrations of asphalt, grease, oil, tar, and rubber particles, whereas runoff
from residential  areas mainly contains leaves,  grass cuttings, and other plant material, and (5)
differences in composition of the soils within the drainage areas of the basins on Long Island  apparently
are not major factors in causing water retention.

       Water-containing  basins dispose of an undetermined amount of storm runoff primarily by the
slow infiltration of water through the bottoms and the sides of the basins. The low average specific
conductance of water in most such basins suggests that evaporation does not significantly concentrate
the chemical constituents  and, therefore, that evaporation is not a major mechanism of water disposal
from these basins.
Asano, T. "Irrigation With Reclaimed Wastewater - Recent Trends."  Irrigation Systems For The
21st Century, Portland, Oregon, 1987. (American Society Of Civil Engineers, New York, New
York, pp. 735-742). 1987.

       Abstract.   Land application of municipal wastewater is a well established practice in California.
Since approximately 33 million acre-feet (4x10^ m^) of water, or about 85 percent of the total water
used in the State are applied annually to approximately 9 million acres (36,400 km^)  of irrigated cropland
(Calif. State Water Resources Control Board, 1981), irrigation with reclaimed wastewater has become a
logical and important component of total water resources planning and development.

       Much of the reclaimed municipal wastewater (57%) in California is used for irrigation of fodder,
fiber and seed crops (a use not requiring a high degree of wastewater treatment), and about 7%  is used
for irrigation of orchard, vine, and other food crops. An important use in recent years (about 14%) is
irrigation of golf courses, other turfgrass, and landscape areas. According to a survey (Crook, 1985)
conducted by California Department of Health Services, approximately 220,000 (271  X 10^ m^) feet of
wastewater is reclaimed by 240 municipal wastewater treatment plants that supply reclaimed water to
more than 380 use areas. Data from the 1984 survey on the types of reuse and numbers of use areas
are listed.
Bao-rui, Y. "Investigation Into Mechanisms Of Microbial Effects On Iron And Manganese
Transformations In Artificially Recharged Groundwater."  Water Science And Technology: A
                                             123

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Journal Of The International Association On Water Pollution Research.  V. 20, n. 3.  pp. 47-53.
1988.

       Abstract.   After artificial recharging of groundwater some problems occurred, such as changes
in groundwater quality, the silting up of recharge (injection) wells, etc. Therefore, the mechanisms of
microbial effects on groundwater quality after artificial recharging were studied in Shanghai and the
district of Changzhou.  These problems were approached on the basis of the amounts of biochemical
reaction products generated by the metabolism of iron bacteria, sulphate-reducing bacteria,  Thiobacillus
thioparus, and Thiobacillus denitrificans. The experiments showed that in the transformations occurring
and the siltation of recharge wells, microorganisms play an important role, due to the various chemical
and biochemical activities. A water-rock-microorganisms system is proposed, and some methods for the
prevention and treatment of these effects are given.


Barraclough, J. T. "Waste Injection Into A Deep Limestone In Northwestern Florida."  Ground
Water. V. 3, n. 1. pp. 22-24. 1966.

       Abstract.   During a three-month trial period, 70 million gallons of industrial wastes were
successfully injected at moderate pressures into a deep limestone in the westernmost part of Florida.
The movement of these wastes is expected to be predominantly southward toward the natural discharge
area which is presumed to be far out in the Gulf of Mexico. The limestone lies between two  thick beds of
clay (aquicludes) and contains 13, 000 parts per million salty water. A series of aquifers and aquicludes
appear capable of preventing contamination of the overlying  fresh-water aquifers.


Boggess, D. H. Effects Of A Landfill On Ground Water Quality.  Geological Survey Open File
Report 75-594.  U.S. Geological Survey, Tallahassee, Florida.  1975.

       Abstract.    Chemical analyses of water from 11 wells were adequate to show definite effects on
ground-water  quality in the vicinity of a landfill site in Lee County, Florida, operated by the city of Fort
Myers. These effects were  observed as far as 1,200 feet (320 metres) down gradient. When compared
to the average concentrations of chemical constituents determined in comparable wells used as controls,
water from the well with the greatest effect had sulfate 72 times greater, potassium 43 times greater,
ammonia nitrogen 20 times greater, sodium and chloride 12 times greater, and most other chemical
constituents 2 to 8 times greater.

       The leachate was transported downgradient in the water- table aquifer in the general direction of
ground-water movement. A subsurface clay barrier and paths of higher permeability apparently caused
some local variation in  the direction of leachate movement. The leachate probably is transported more
rapidly during  high stages of the water table due to higher hydraulic gradients and increased
transmissivity.

       Because of the high water table,, which is at or near the land surface during periods of maximum
recharge from rainfall, extensive modification of the waste-disposal procedures would be required to
reduce or eliminate the effect of the leachate.


Bouchard, A. B. "Virus  Inactivation Studies For A California Wastewater Reclamation Plant."
Water Environment Federation 65th Annual Conference & Exposition, New Orleans, Louisiana,
1992. (Water Environment Federation, Alexandria, Virginia). 1992.
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       Abstract.   Engineering-Science, Inc. (ES) was retained by Thetford Systems, Inc. to develop,
implement and supervise a virus inactivation study program for the Thetford Cycle-Let Wastewater
Reclamation System. Thetford has installed a Cycle-Let system at the Water Garden Development
Project in Santa Monica, California, to treat the collected municipal sewage from the project's office
buildings and facilities. The Water Garden Cycle-Let system will  produce reclaimed water for use as
landscape irrigation for the development's property, and as make-up water for an on-site decorative lake.
Phase II of the Water Garden Project proposes to use the reclaimed water as a source of toilet flush
water in the office buildings. The State of California has established treatment process criteria required
for certain types of reclaimed water use. Specifically, the California Administrative Code Title 22
identifies the processes required to treat municipal wastewater prior to reuse. Title 22 stipulates the
following treatment processes to use reclaimed water as landscape irrigation - oxidation, clarification,
coagulation, filtration and disinfection using chlorination. The Thetford Cycle-Let extended aeration
activated sludge with biological nitrification, followed by ultramembrane filtration, granular activated
carbon adsorption, and ultraviolet light disinfection. As such, the California Department of Health
Services (DOHS) has the requirements of Title 22. These requirements stipulate that the median
number of coliform organisms in the plant effluent does not exceed 2.2 MPN per 100 milliliters and that
the effluent must be essentially pathogen free. ES was retained by Thetford to develop a DOHS
approved testing protocol, to implement the test program, to supervise the test program, and to prepare
an engineering report to be submitted to the DOHS that demonstrates the adequacy of the extensive
seeded virus inactivation study, followed by an in-situ virus study, and the necessary bacteriological
analyses.  Since the Water Garden Project is still under construction  and  no wastewater is being
currently generated, the study was conducted at a similar facility that serves an office park in Princeton,
New Jersey. The effluent from the Cycle-Let system at this plant is used for toilet flush water in the
office complex.  By conducting the study at this plant,  ES was able to test the Cycle-Let system's
adequacy of meeting Title 22 and the possibility of using reclaimed water as toilet flush water for the
Water Garden Project.


Bouwer, E. J., P. L. McCarty, H. Bouwer and R.  C. Rice. "Organic Contaminant Behavior  During
Rapid Infiltration Of Secondary Wastewater At The Phoenix 23rd Avenue Project."  Water
Resource. V. 18, n. 4. pp. 463-472. 1984.

       Abstract.   Movement of trace organic pollutants during rapid infiltration of secondary
wastewater for groundwater recharge was studied  at the 23rd Avenue Rapid Infiltration Project in
Phoenix, Arizona. Samples of the wastewater applied to the spreading basins and of renovated water
taken from monitoring wells were characterized for priority pollutants and other specific organic
compounds using gas chromatography/mass spectrometry. The concentrations of organic constituents
were affected by volatilization, biodegradation and  sorption processes. Nonhalogenated aliphatics and
aromatic hydrocarbons exhibited concentration decreases of 50-99% during  soil percolation.
Halogenated organic compounds were generally removed to a lesser extent. Concentrations of
trichloroethylene, tetrachloroethylene, and pentachloroanisole appeared to be significantly higher in the
renovated water than in the basin water; reasons for this behavior remain unclear.  Many organic
contaminants were detected in the groundwater indicating such systems should be designed to localize
contamination of the aquifer. Chlorination of the wastewater had no significant effect on concentrations
and types of trace organic compounds.


Bouwer, H.  "Agricultural Contamination:  Problems And Solutions." Water Environment And
Technology.  V. 1,n. 2. pp. 292-297. 1989.

       Abstract.   Salts from irrigation water concentrate in the deep percolation water and can pollute
                                              125

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groundwater, especially in dry climates where there is little natural dilution. Under certain geologic
conditions, selenium and other trace elements may leach from the root and vadose zones into the
groundwater. Salt and trace element contamination is a direct result of agricultural activities, but neither
is caused by anthropogenic chemicals, such as nitrate and pesticides, which can cause severe
groundwater contamination.

        Not long ago, it was thought that pesticides would not migrate to groundwater except, perhaps,
under situations of very coarse or cracked soils, shallow groundwater tables, high pesticide application
rates, or accidental spills. In the mid- to late-1970s, more and more cases of pesticide contamination
were reported as well testing increased and more sensitive analytical equipment was used. The problem
is now widespread. Many pesticides have been detected in groundwater, and thousands of wells have
been closed.

        Nitrogen-containing fertilizers also threaten groundwater quality because they produce nitrate in
the soil.  Nitrate moves readily with deep percolation through the vadose zone to groundwater. Thus,
nitrogen not used by crops or denitrified in the soil and volatilized eventually appears as nitrate in
groundwater. Nitrate concentrations in vadose-zone water beneath agricultural  fields typically range
from 5 to 100 mg/L and are often 20 to 40 mg/L -- 10 to 30 mg/L greater than the maximum drinking
water limit.

        Growing concern over groundwater contamination caused by fertilizer and pesticide use  has
triggered an increase in legislative and regulatory activity. However, more research, including that on
health  effects and acceptable risks,  is needed to establish sound regulations. Contaminant migration
must also be better understood so that pesticide transport can be more accurately predicted.  Preventing
contamination is more effective than cleaning polluted aquifers and, for this purpose, best management
practices (BMPs) must be developed.  Realistic regulatory policies and management practices that will
protect public health while ensuring  viable and sustainable agriculture must be implemented.


Bouwer, H. "Effect Of Irrigated Agriculture On Groundwater."  Journal of Irrigation and Drainage
Engineering. V. 113, n. 1. pp.  4-15.  1987.

        Abstract.   The time  it takes for deep percolation water from irrigated fields to reach underlying
groundwater increases with decreasing particle size of the vadose zone material and increasing depth to
groundwater.  For average deep  percolation rates, decades  may be required before the water joins the
groundwater.  Due to nonuniform irrigation applications and  preferential flow, some deep percolation
water will reach the groundwater much faster.  Dissolved salts, nitrate, and pesticides are the chemicals
in deep percolation water of main concern in groundwater pollution. Movement of pesticides may be
retarded in the vadose zone, but biodegradation may also be slowed due to reduced organic carbon
content and microbial activity at greater depths.  Because of the large area of irrigated land in the world
and the real potential for groundwater pollution, more research is necessary on downward movement of
water and chemicals in the vadose zone.
Bouwer, H. and E. Idelovitch. "Quality Requirements For Irrigation With Sewage Water ."
Journal of Irrigation and Drainage Engineering.  V. 113, n. 4.  pp. 516-535.  1987.

        Abstract.   Irrigation is an excellent use for sewage effluent because it is mostly water with
nutrients.  For small flows, the effluent can be used on special, well-supervised "sewage farms," where
forage, fiber, or seed crops are grown that can be irrigated with standard primary or secondary effluent.
Large-scale use of the effluent requires special treatment so that it meets the public health, agronomic,
                                              126

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and aesthetic requirements for unrestricted use (no adverse effects on crops, soils, humans, and
animals).  Crops in the unrestricted-use category include those that are consumed raw or brought raw
into the kitchen.  Most state or government standards deal only with public health aspects, and prescribe
the treatment processes or the quality parameter that the effluent must meet before it can. be used to
irrigate a certain category of crops.  However, agronomic aspects related to crops and soils must also be
taken into account. Quality parameters to be considered include bacteria, viruses, and other pathogens;
total salt content and sodium adsorption ratio of the water (soil as well as crop effects); nitrogen;
phosphorus; chloride and chlorine; bicarbonate; heavy metals, boron, and other trace elements; pH; and
synthetic organics (including pesticides).


Brown, D. P. Effects Of Effluent Spray Irrigation On Ground Water At A Test Site Near Tarpon
Springs, Florida. Geological Survey Open-File Report 81-1197. U.S. Geological Survey,
Tallahassee, Florida. 1982.

       Abstract.   Secondary-treated effluent was applied to a 7.2-acre test site for about 1 year at an
average rate of 0.06 million gallons per day and 3 years at 0.11 million gallons per day.  Chemical
fertilizer was applied periodically to the test site and adjacent areas. Mounding of the water table
occurred due to effluent irrigation, inducing radial flow from the test site.
       Ground water in the surficial aquifer at the test site and adjacent  areas showed substantial
increases in most chemical and physical parameters (including chloride,  specific conductance, pH, total
nitrogen,  and total carbon) above the range of values observed in nearby areas that were irrigated with
water from the Floridan aquifer and periodically fertilized.

       In the surficial aquifer, about 200 feet downgradient from the test site, physical, geochemical,
and biochemical processes effectively reduced total nitrogen concentration 90 percent and total
phosphorus concentration more than 95 percent from that of the applied effluent. In the effluent, total
nitrogen averaged 26 milligrams per liter and total phosphorus averaged 7.3 milligrams per liter.
Downgradient, total nitrogen averaged 2.4 milligrams per liter and total phosphorus averaged 0.17
milligrams per liter. Increases in total phosphorus concentration were observed where the pH of ground
water increased.

       Microbiological data did not indicate fecal contamination in the surficial aquifer.  Fecal coliform
bacteria were generally less than 25 colonies per 100 milliliters at the test site  and were not detected
downgradient or near the test site. Fecal streptococcal bacteria were generally less than 100 colonies
per 100 milliliters at the test site and on three occasions were detected adjacent to the test site. In the
Floridan aquifer, total and fecal coliform bacteria were detected in 50 percent of the samples. Total
coliform bacteria were generally less than 100 colonies per 100 milliliters and fecal colifoorm bacteria
were generally less than  10 colonies per 100 milliliters. .


Butler, K. S.  "Urban Growth Management And Groundwater Protection:  Austin, Texas."
Planning For Groundwater Protection.  Academic Press, New York, New  York.  pp. 261-287. 1987.

       Abstract.   Austin, Texas has recognized that the greatest opportunity to prevent declining
groundwater quality is through proper location, design, construction, and  maintenance of new urban
development and its associated drainage systems.  Increasing development in the environmentally
sensitive watersheds south and west of Austin resulted in the promulgation of  a series of innovative
watershed development ordinances in the early 1980s (Butler, 1983). These regulations are designed to
protect the water quality of the Edwards Aquifer, a unique karstic limestone system. This process of
planning for the protection of groundwater is the subject of this chapter.
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       Specifically, this chapter concerns the effects that the ordinances for several watersheds and the
associated aquifer will have on suburban land development and water quality protection for the Edwards
Aquifer. These ordinances are salient examples of a new, largely untested venture into urban runoff
pollution control using a combination of engineering and land use management techniques. The
immediate motivation for adopting these 4 techniques is protecting groundwater and spring discharges
from degradation and contamination with nontoxic chemicals. Austin also recognized that toxic
contaminants may become a threat to groundwater. The combination of engineering and land use
management techniques as adopted in Austin's ordinances should protect the groundwater from organic
and inorganic microcontaminants as well as more common pollutants associated with urban storm runoff.

       This chapter addresses three key questions: Why is the Edwards Aquifer are so deserving of
special protection in the face of urban expansion?  How do these development standards affect the
planning of new subdivisions and site developments? And how do groundwater quality  protection
standards operate in the broader context of growth management in this rapidly urbanizing region of
central Texas?
Cavanaugh, J. E., H. S. Weinberg, A. Gold, R. Sangalah, D. Marbury, W. H. Glaze, T. W. Collette, S.
D. Richardson and A. D. Thruston Jr. "Ozonation Byproducts:  Identification Of Bromohydrins
From The Ozonation Of Natural Water With Enhanced Bromide Levels." Environmental Science
^Technology.  V. 26, n. 8.  pp. 1658-1662. 1992.

       Abstract.  When ozone is used in the treatment of drinking water, it reacts with both inorganic
and organic compounds to form byproducts.  If bromide is present, it may be oxidized to hypobromous
acid, which may then react with natural organic matter (NOM) to form brominated organic compounds.
The formation of bromoform has been well documented and more recently, other byproducts, such as
bromoacetic acids, bromopicrin, cyanogen bromide, bromoacetones, and bromate, have been identified.
The purpose of this communication is to report the identification of bromohydrins, a new group of labile
brominated organic byproducts from the ozonation of a natural water in the presence of enhanced levels
of bromide.
Chang, A. C., A. L. Page, P. F. Pratt and J. E. Warneke. "Leaching Of Nitrate From Freely Dralned-
Irrigated Fields Treated With Municipal Sludges." Planning Now For Irrigation And Drainage In
The 21st Century, Lincoln, Nebraska, 1988. (American Society Of Civil Engineers, New York, New
York, pp. 455-467).  1988.

       Abstract.  A municipal sludge land application experiment was initiated in 1975 near
Riverside, California.  From 1975 to 1983  sludges from the Los Angeles Metropolitan Area were applied
on experimental plots where crops were grown annually.  Results indicated that (1) crop yields were not
affected by the sludge application and the total biomass harvested was a function of total  N input, (2) the
extent and the rate of N mineralization of liquid sludges were consistently higher than composted sludges
and the sludge application rate and the soil type did not affect  mineralization of N, and (3) nitrogen
application exceeding N  requirements for crop growth always results in leaching and accumulation of
nitrate in the soil profile.


Chase, W. L. J. "Reclaiming Wastewater In Phoenix, Arizona." Irrigation Systems For The 21st
Century, Portland, Oregon, 1987. (American  Society Of Civil Engineers, New York, New York, pp.
336-343). 1987.
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        Abstract.   This paper examines the role of wastewater effluent reuse in the future water
resource management of the City of Phoenix. The paper seeks to explain why a proposal to renovate
effluent through rapid infiltration land treatment and to recycle that renovated water for agricultural
irrigation has still not been implemented 20 years after the first serious studies of this project were
initiated by the Salt River Project and the U.S. Department of Agriculture's Water Conservation
Laboratory in Phoenix.  While answering the technical questions concerning the safety of using
renovated wastewater effluent for unrestricted agricultural irrigation accounted for a little of over half of
that time, the primary problems since 1982 have been economic, legal and institutional.


Cisic, S., D. Marske, B. Sheikh, B. Smith and F. Grant. "City Of Los Angeles Effluent - Today's
Waste, Tomorrow's Resource."  Water Environment Federation 65th Annual Conference &
Exposition, New Orleans, Louisiana, 1992. (Water Environment Federation, Alexandria, Virginia).
1992.

        Abstract.   The City Of Los Angeles (City) receives water from three sources. In an average
year,  70 percent of the water used to come from the Eastern Sierra Nevada via the Los Angeles
Aqueduct; wells in the San Fernando Valley and other local groundwater basins supplied 16 percent; and
purchases from the Metropolitan Water District of Southern California (Metropolitan) provided the
remaining 14 percent. Faced with the fifth consecutive year of drought and supply cut from all three
present sources, the City is planning to tap into a fourth - its wastewater.


Close, M. E.  "Effects Of Irrigation On Water Quality Of A Shallow Unconfined Aquifer."  Water
Resources Bulletin. V. 23, n. 5.  pp. 793-802. 1987.

        Abstract.   The ground water quality of a shallow unconfined aquifer was monitored before and
after implementation of a border strip irrigation scheme, by taking monthly samples from an array of 13
shallow wells. Two 30 m deep wells were sampled to obtain vertical concentration profiles. Marked
vertical, temporal, and spatial variabilities were recorded.  The  monthly data were analyzed for step and
linear trends using nonparametric tests that were adjusted for the effects of serial correlation. Average
nitrate concentrations increased in the preirrigation period and decreased after irrigation began. This
was attributed to wetter years in 1978-1979 than 1976-1977 which increased leaching, and to disturbance
of thetopsoil  during land contouring before irrigation, followed by excessive drainage after irrigation.
Few significant trends were recorded for other determinants, possibly because of shorter data records.

        Nitrate, sulphate, and potassium concentrations decreased with depth, whereas sodium, calcium,
bicarbonate, and chloride concentrations increased. These trends allowed an estimation to be made of
the depth of ground water affected by percolating drainage. This depth increased during the irrigation
season and after periods of winter  recharge. Furthermore, an overall increase in the depth of drainage-
affected ground waster occurred with time, which paralleled the development of the irrigation scheme.


Clothier, B. E. and T. J. Sauer. "Nitrogen Transport During Drip Fertigation With Urea." Soil
Science Society Of America Journal. V. 52, n. 2. pp. 345-349. 1988.

       Abstract.    Urea added to drip  irrigation water will be rapidly hydrolyzed in the soil to
ammonium and then oxidized to nitrate.  An approximate theory is presented for the unsteady, three-
dimensional transport of water and N through unsaturated soil around a dripper discharging a urea
solution. The results were compared with measurements from  laboratory experiments with repacked silt
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loam. Water and solute movement in the course of the irrigation cycle and during the subsequent
redistribution are considered. The theory successfully located the penetration of both the inert nitrate
and reactive ammonium derived from the applied urea. It was possible to predict the direction, and
approximated the magnitude of pH changes proximal to the emitter.


Craun, G. F. "Waterborne  Disease - A Status Report Emphasizing Outbreaks In Ground-Water
Systems."  Ground Water.  V. 17, n. 2. pp. 183-191. 1979.

       Abstract.    A total of 192 outbreaks of waterborne disease affecting 36,757 persons were
reported in the United States during the  period 1971-1977.  More outbreaks occurred in nonmunicipal-
water systems (70 %) than municipal-water systems; however, more illness (67 %) resulted from
outbreaks in municipal systems. Almost half of the outbreaks (49 %) and illness (42 %) were caused by
either the use of untreated or inadequately treated ground water. An unusually large number of
waterborne outbreaks affected travelers, campers, visitors to recreational areas, and restaurant patrons
during the months of May-August and involved nonmunicipal-water systems which primarily  depend on
ground-water sources. The major causes of outbreaks in municipal systems were contaminations of the
distribution systems and treatment deficiencies which accounted for 68 % of the outbreaks and 75% of
the illness that occurred in municipal systems.  Use of untreated ground water was responsible for only
10% of the municipal system outbreaks  and 1 % of the illness. The major cause of the outbreaks in
nonmunicipal systems was used of untreated ground water which accounted for 44% of the outbreaks
and 44% of the illness in these systems. Treatment deficiencies, primarily inadequate and interrupted
chlorination of ground- water sources, were responsible for 34% of the outbreaks and 50% of the illness
in nonmunicipal-water systems.


Crltes, R. W. "Micropollutant Removal In Rapid Infiltration." Artificial Recharge Of Groundwater.
Butterworth Publishers, Boston, pp.  579-608. 1985.

       Abstract.    In a rapid-infiltration land treatment system, wastewater is treated as it percolates
through the soil. The wastewater is applied to moderately and highly permeable soils (such as sands) by
surface spreading  in level basins or by sprinkling. Treatment is accomplished by biologic, physical and
chemical means within the soil.

       The need for definitive information on the extent of  soil treatment during  rapid  infiltration has
been recognized.  Rapid infiltration is effective in removing many wastewater constituents such as
suspended solids, 6005, ammonium-nitrogen, phosphorus, bacteria, and virus and is less effective in
removing other constituents such as nitrate-nitrogen, trace organics, and trace minerals.

       The  constituents addressed in this chapter include trace organics, inorganics (those  covered by
drinking water standards),  and microorganisms. For these three classes of constituents, the health
effects, removal mechanisms and removals in existing rapid infiltration systems are discussed.


Crook, J., T. Asano and M. Nellor. "Groundwater Recharge With Reclaimed Water In California."
Water Environment & Technology. V. 2, n. 8. pp. 42-49.  1990.

       Abstract.   In California, increasing demands for water have given rise to surface water
development and large-scale projects for water importation.  Economic and environmental concerns
associated with these projects have expanded  interest in reclaiming municipal wastewater to supplement
existing water supplies.  Groundwater recharge represents a large potential use of reclaimed water in the
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state. For example, several projects have been identified in the Los Angeles area that could use up to
150 X 106 m3/a (120,000 ac-ft/yr) of reclaimed water for groundwater recharge.  Recharging
groundwater with reclaimed wastewater has several purposes: to prevent saltwater intrusion into
freshwater aquifers, to store the reclaimed water for future use, to control or prevent ground subsidence,
and to augment nonpotable or potable groundwater aquifers.  Recharge can be accomplished by surface
spreading or direct injection.

       With surface spreading, reclaimed water percolates from spreading basins through an
unsaturated zone to the groundwater. Direct injection entails  pumping reclaimed water directly into the
groundwater, usually into a confined aquifer. In coastal areas, direct injection effectively creates barriers
that prevent saltwater intrusion. In other areas, direct injection may be preferred  where groundwater is
deep or where the topography or existing land use makes surface spreading impractical or too
expensive.  While only two large-scale, planned operations for groundwater recharge are using
reclaimed water in California, incidental or unplanned recharge is widespread.

       The constraints of groundwater recharge with reclaimed water include water quality, the potential
for health hazards, economic feasibility, physical limitations, legal restriction, and the availability of
reclaimed water. Of these concerns, the health concerns are  by far the most important, as they pervade
all potential recharge projects.  Health authorities emphasize that indirect potable reuse of reclaimed
wastewater through groundwater recharge encompasses a much broader range of potential risks to the
public's health than nonpotable uses of reclaimed water. Because the reclaimed  water eventually
becomes drinking water and is consumed, health effects associated with prolonged exposure to low
levels of contaminants and acute health effects from pathogens or toxic substances must be considered.
Particular attention must be given to organic and inorganic substances that may elicit adverse health
responses in humans after many years of exposure.


Deason, J. P. "Irrigation-Induced Contamination:  How Real A Problem?" Journal of Irrigation
and Drainage Engineering. V. 115, n. 1. pp. 9-20.  1989.

       Abstract.   The U.S. Department of the Interior has embarked on a series of reconnaissance-
level investigations throughout the western states to identify, evaluate, and respond to irrigation-induced
water quality problems. A series of water, sediment, and biological samples are being analyzed for 17
inorganic constituents and a number of pesticides. 19 studies in 13 states have been undertaken.
Seven have been completed to date. Results of the seven studies that have been completed are
presented and compared to baselines, standards, criteria, and other guidelines helpful for assessing the
potential of observed constituent concentrations in water, bottom sediment, and biota, to result in
physiological harm to fish, wildlife, or humans.  These initial results indicate that a new environmental
problem of major proportions does not exit, but that some localized problems of significant magnitude do
exist and should be addressed.
Deason, J. P. "Selenium:  It's Not Just In California." Irrigation Systems For The 21st Century,
Portland,  Oregon, 1987. (American Society Of Civil Engineers, New York, New York, pp. 475-482).
1987.

       Abstract.   The U.S. Department of the Interior has embarked on a series of reconnaissance
level investigations throughout the western states to identify and assess potential irrigation-induced water
quality problems. A series of water, sediment and biological samples are being analyzed for selenium
and 16 other trace elements, as well as a number of pesticides.  Nine studies in seven states are
underway  currently and 10 additional locations for study have been identified.
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 DeBoer, J. G. "Wastewater Reuse:  A Resource Or A Nuisance?"  Journal of the American Water
 Works Association. V. 75, . pp. 348-356. 1983.

        Abstract.   As demand for good quality water increases, some areas in the United States find
 that traditional finite sources cannot meet all needs, although many utilities draw potable supplies from
 water that has previously been used upstream, the direct reuse of treated water for potable supplies is
 limited by unknowns concerning health effects and by  costs.  Planned reuse options, however, are
 feasible water conservation techniques, especially for  industrial and agricultural uses.  Reclaimed
 wastewater can also be used to recharge groundwater, thereby augmenting potable supplies.


 Domagalski, J. L. and N. M. Dubrovsky. "Pesticide Residues In Ground Water Of The San
 Joaquin Valley, California." Journal Of Hydrology. V. 130, n. 1-4. pp. 299-338.  1992.

        Abstract.   A regional assessment of non-point-source contamination of pesticide residues in
 ground water was made of the San Joaquin Valley, an intensively farmed and irrigated structural trough
 in central California. About 10% of the total pesticide  use in the USA is in the San Joaquin Valley.
 Pesticides detected  include atrazine, bromacil, 2,4-DP, diazinon, dibromochloropropane, 1,2-
 dibromoethane, dicamba, 1,2-dichloropropane, diuron, prometon, prometryn, propazine and simazine.
 All are soil applied except diazinon.

        Pesticide leaching is dependent on use patterns, soil texture, total organic carbon in soil,
 pesticide half-life and depth to water table. Leaching is enhanced by flood-irrigation methods except
 where the pesticides is foliar applied such as diazinon. Soils in the western San Joaquin Valley are fine
 grained and are derived primarily from marine  shales of the Coast Ranges.  Although  shallow ground
 water is present, the fewest number of pesticides were detected in this region.  The fine- grained soil
 inhibits pesticide leaching because of either low vertical  permeability or high surface area; both enhance
 adsorption on to solid phases.  Soils in the eastern part of the valley are coarse grained with low total
 organic carbon and are derived from Sierra Nevada granites.  Most pesticide leaching is in these alluvial
 soil, particularly in areas where depth to ground water  is less than 30 m. The areas currently most
 susceptible to pesticide leaching are eastern Fresno and Tulare Counties.

        Tritium in water molecules is an indicator of aquifer recharge with water of recent origin.
 Pesticide residues transported as  dissolved species were not detected  in non- tritiated water. Although
 pesticides were not detected in all samples containing high tritium, these samples are indicative of the
 presence of recharge water that interacted with agricultural soils.


 Ehrlich, G. G., E. M. Godsy, C. A. Pascale and J. Vecchioli. "Chemical Changes In An Industrial
 Waste Liquid During Post- Injection Movement In A Limestone Aquifer, Pensacola, Florida."
 Ground Water. V. 17, n. 6. pp. 562-573. 1979a.

        Abstract.   An industrial  waste liquid  containing organonitrile compounds and nitrate ion has
 been injected into the lower limestone of Floridan aquifer near Pensacola, Florida since June 1975.
 Chemical analyses of water from monitor wells and backflow from the injection well indicate that organic
 carbon compounds are converted to CC>2 and  nitrate is converted to N2-  These transformations are
 caused by bacteria immediately after injection, and are virtually completed within 100 m of the injection
well. The zone near the injection well behaves like an anaerobic filter with nitrate respiring bacteria
dominating the microbial flora in this zone.
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       Sodium thiocyanate contained in the waste is unaltered during passage through the injection
zone and is used to detect the degree of mixing of injected waste liquid with native water at a monitor
well 312 m (712 ft) from the injection well.  The dispersivity of the injection zone was calculated to be 10
m (33 ft). Analyses of samples from the monitor well indicate 80 percent reduction in chemical oxygen
demand and virtually complete loss of organonitriles  and nitrate from the waste liquid during passage
from the injection well to the monitor well.  Bacteria densities were much lower at the monitor well than in
backflow from the injection well.


Ehrlich, G. G., H. F. H. Ku, J. Vecchioli and T. A. Ehlke. Microbiological Effects Of Recharging
The Magothy Aquifer, Bay Park, New York, With Tertiary-Treated Sewage. Geological Survey
Professional Paper 751-E. U.S. Government Printing Office, Washington, D.C. 1979b.

       Abstract.   Injection of highly treated sewage (reclaimed water) into a sand aquifer on Long
Island, N.Y., stimulated microbial  growth near the well screen. Chlorination of the injectant to 2.5
milligrams per liter suppressed microbial growth to the extent that it did not contribute significantly to
head buildup during injection.  In the absence of chlorine, microbial growth caused extensive well
clogging in a zone immediately adjacent to the well screen.

       During a resting period of several days between injection and well redevelopment, the inhibitory
effect of chlorine dissipated and microbial growth ensued.  The clogging mat at the well/ aquifer interface
was loosened during this period, probably  as a result of microbial activity.

       Little microbial activity was noted in the aquifer beyond 20 feet from the well screen; this activity
probably resulted from small amounts of biotransformable  substances not completely filtered out of the
injectant by the aquifer materials.

       Movement of bacteria from the injection well into the aquifer was not extensive. In one test, in
which  injected water had substantial total-colrform, fecal-coliform, and fecal-streptococcal densities , no
fecal- coliform or fecal - streptococcal bacteria, and only nominal total-col if orm bacteria, were found in
water from an observation well 20 feet from the point of injection.


Elder, J. F., J. D. Hunn and C. W. Calhoun. Wastewater Application By Spray Irrigation On A
Field Southeast Of Tallahassee, Florida: Effects  On Ground-Water Quality And Quantity.
Geological Survey Water-Resources Investigations Report 85-4006.  U.S. Geological Survey,
Tallahassee, Florida. 1985.

       Abstract.   An 1,840-acre agriculture field southeast of Tallahassee, Florida, which has been
used for land application of wastewater by  spray irrigation, is the site of a long-term, ground-water
monitoring study.  The purpose of the study is to determine effects of wastewater application on water-
table elevations and ground-water quality.  The study was  conducted in cooperation with the City of
Tallahassee.  This report summarizes the findings for the period 1980-82.

       Wastewater used for spray irrigation has high concentrations, relative to those in ground water,
of chloride, nitrogen, phosphorus, organic carbon, coliform bacteria, sodium, and potassium. At most
locations, percolation through the soil has been quite effective in attenuation of these substances before
they can impact the ground water. However, increases in chloride and nitrate-nitrogen were evident in
ground water in some of the monitoring wells during the study, especially those wells which are within the
sprayed areas. Chloride concentrations, for example, increased from approximately 3 milligrams per
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liter to 15 to 20 milligrams per liter in some wells and nitrate-nitrogen concentrations increased less than
0.5 milligrams per liter to 4 milligrams per liter or more.

       Ground-water levels in the area of the spray field fluctuated over a range of several feet.  These
fluctuations were affected somewhat  by spray irrigation, but the primary control on water levels was
rainfall.

       As of December 1982, constituents introduced to the system by spray irrigation of effluent had
not exceeded drinking water standards  in the ground water. The system has not yet stabilized, however,
and more changes in ground-water quality may be expected.


Eren, J.  "Changes In Wastewater Quality During Long Term Storage."   pp. 1291-1300.

       Abstract.   The rainfall in Israel is in the winter months November-April and the irrigation period
is during the summer months May-October. Cotton which is the main crop irrigated by reused wastewater
requires irrigation during 3 months (June- August) only.

       Therefore wastewater reuse projects require facilities to store the winter effluents for summer
utilization.

       It is either underground storage in sandy aquifers as in the Dan Region reclamation project or
storage in deep wastewater reservoirs which are used in all the other projects. The largest of these
reservoirs is the Maale Kishon (Upper Kishon) Reservoir which is part of the Kishon Project that reuses
wastewater from the Haifa Metropolitan Region.

       The storage duration is few weeks up to several months and during this period there is intense
biological activity which causes significant changes  in water quality in the reservoirs.  In a preliminary
study in a small reservoir (1) prior to the construction of the Maale  Kishon  Reservoir it was observed that
6 weeks storage improved considerably the water quality. The purpose of this investigation was to
determine the changes that occur in relative large water body and how those affect those parameters
which are important for agricultural irrigation.


Ferguson, B. K. "Role Of The Long-term Water Balance In Management of Stormwater
Infiltration."  Journal Of Environmental Management. V. 30, n. 3. pp. 221-233. 1990.

       Abstract.   Artificial infiltration of urban stormwater can potentially recharge ground water and
sustain stream base flows while improving stormwater quality and  contributing to flood control. It
involves capturing stormwater in basins where it is stored while infiltrating the surrounding soil. This
paper suggests that management of these basins with design-storm approaches needs to be
supplemented by the long-term water balance incorporates continuous low-level background flows, in
contrast to the design storm, which is an isolated, rare and brief event. Background flows can
accumulate in basins with no regular surface outlets, potentially reducing basin capacity and causing
nuisances associated with standing water.  A model is described for routing monthly average flows
through infiltration basins. Using this model, 12 infiltration basins representing different construction
methods and management objectives were designed for a hypothetical catchment in the Atlanta area.
The effects of these basins in terms of cost, presence of standing water, capture of flood flows and
average annual disposition of water were evaluated. The results show that background flows cannot be
disregarded in infiltration management, since the performance of basins designed without considering
background flows can be considerably hampered by their presence. The results also invite discussion of
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alternative basin geometries, materials and hydroperiods as ways of meeting site-specific objectives for
water resources and urban amenities.
Ferguson, R. B., D. E. Eisenhauer, T. L. Bockstadter, D. H. Krull and G. Buttermore.  "Water And
Nitrogen Management In Central Platte Valley Of Nebraska."  Journal Of Irrigation And Drainage
Engineering. V. 116, n. 4.  pp. 557-565. 1990.

       Abstract.   Contamination of ground water by nitrogen leached from fertilizer on irrigated soils
is related to the quantity of nitrate-N (NO3'-N) present, the leaching potential based on soil texture and
percent depletion of available soil water in the root zone, and the amount of water entering the soil
profile. Research and demonstration projects in the central Platte valley of Nebraska have shown that
NOs'-N leaching is influenced by  both irrigation and fertilizer-nitrogen (N) management in corn
production. Scheduling irrigation according to available soil-water depletion can reduce deep percolation
to a certain extent.  Additional reduction in deep percolation can be achieved by improving efficiency of
water application, particularly on furrow irrigated fields. Testing for NOs'-N in irrigation water and soil
can provide for substantial reductions in fertilizer N application, if residual levels in the soil are  high, or if
considerable NO3~-N will be applied with irrigation  water.  Grain yields were not appreciably affected by
the use of these management practices, while in most cases input costs for fertilizer nitrogen and
irrigation water were reduced.


Gerba, C. P. and S. M. Goyal. "Pathogen Removal From Wastewater During Groundwater
Recharge." Artificial Recharge Of Groundwater. Butterworth Publishers, Boston, pp. 283-317.
1985.

       Abstract.   Groundwater contamination by pathogenic microorganisms has not received as
much attention as surface water pollution because  it is generally assumed that groundwater has a good
microbiologic quality and is free of pathogenic microorganisms. A number of well-documented disease
outbreaks have, however, been traced to contaminated groundwater. A total of 673 waterborne
outbreaks affecting 150,268 persons occurred in the United States from 1946 to 1980.  Of these, 295
(44%) involving 65,173 cases were attributed to contamination of groundwater.

       Currently, 20 percent of the total water consumed in the United States is drawn from
groundwater sources and it estimated that this usage will increase to 33 percent in the year 2000.
According to Duboise et al. over 60 million people  in the United States are served by public water
supplies using groundwater, and about 54 percent  of rural population and 2 percent of the urban
population obtain their water from individual well. Since groundwater is often used for human
consumption without any treatment, it is imperative to understand the fate of pathogenic microorganisms
during land application of wastewater.

       The sources of fecal contamination may include septic tanks, leaky sewer lines, lagoons and
leaching ponds, sanitary landfills for solid wastes, and sewage oxidation ponds. Additional sources of
pathogens in groundwater may involve artificial recharge of groundwater aquifers with renovated
wastewater including deep well injection, spray irrigation of crops and landscape,  basin recharge, and
land application of sewage effluent and sludges. Leakage of sewage into the groundwater from septic
tanks, treatment lagoons and leaky sewers is estimated to be over a trillion gallons a year in the United
States.

       It should be realized that,  as opposed to surface water pollution, contamination of groundwater is
much more persistent and is difficult to eradicate.  Because restoration of groundwater quality is difficult,
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time-consuming, and expensive, efforts should be made for the protection of groundwater quality rather
than only for its restoration after degradation.


Gerba, C. P. and C. N. Haas.  "Assessment Of Risks Associated With Enteric Viruses In
Contaminated Drinking Water."  Chemical And Biological Characterization Of Sludges,
Sediments, Dredge Spoils, And Drilling Muds. ASTM STP 976. American Society For Testing
And Materials, Philadelphia, Pennsylvania,  pp. 489-494. 1988.

       Abstract.    It is  now well established that enteric viruses, such as hepatitis  A,  Norwalk,
rotavirus, and so forth, can be transmitted by sewage-contaminated water and food. Standards for
viruses in water have been suggested by the World Health Organization and several other organizations.
Few attempts have been  made to assess the risks associated with exposure to low numbers of enteric
viruses in the environment.

       To determine the risks that may be associated with exposure to human enteric viruses, the
literature on minimum infectious dose, incidence of clinical illness, and mortality was reviewed. This
information was then used to assess the probability of infection, illness, and mortality for individuals
consuming drinking water containing various concentrations of enteric viruses. Risks were determined
on a daily, annual, and lifetime basis.  This analysis suggested that significant risks of illness(>1:1 000
000) may arise from the  exposure to low levels of the enteric virus.


German, E. R.  Quantity And Quality Of Stormwater Runoff Recharged To The Floridan Aquifer
System Through  Two Drainage Wells In The Orlando, Florida, Area.  Geological Survey Water
Supply Paper 2344. U.S. Government Printing Office, Washington, D.C.  1989.

       Abstract.    Quantity and quality of inflow to two drainage wells in the Orlando,  Fla. .area were
determined for the period April 1982 through March 1983.  The wells, located at Lake Midget and at Park
Lake, are used to control the lake levels during rainy periods. The lakes receive stormwater runoff from
mixed residential-commercial areas of about 64 acres (Lake Midget) and 96 acres (Park Lake) and would
frequently flood adjacent  areas if the wells did not drain the excess stormwater. These lakes and wells
are typical of stormwater  drainage systems in the area.

       Lake stages were monitored and  used to estimate quantities of drainage-well inflow. Estimated
inflow for April 1982 through March 1983 was 62.4 acre-feet at Lake Midget and 84.0 acre-feet at Park
Lake. Inflow to the drainage wells was sampled periodically. The quality of water prior to inflow to the
drainage wells was estimated from samples of stormwater runoff to the lakes. The quality of formation
water near the wells was  estimated from samples pumped from the two drainage wells,  a
reconnaissance sampling of inflow at seven other drainage wells in the Orlando area was done, once at
each well, to broaden the areal coverage of the investigation. The laboratory analyses included
determinations of selected nutrients, bacteria, major constituents, trace elements, and numerous organic
compounds , including many designated priority pollutants by the U.S. Environmental Protection Agency.

       Comparison of quality of drainage-well inflow with State criteria for drinking water supply
indicated that color and bacteria were excessively high, and pH excessively low, in some samples.
Constituents that exceeded the criteria were iron, in 10 to 21  inflow samples, manganese, in 1 sample,
and lead, in 1  sample.

       The priority pollutant dibenzo(a,h)anthracene was present in one of two sample  pumped from the
Lake Midget drainage well (concentration of 370 micrograms per liter).  The presence of this compound
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in that high a concentration is puzzling because it was not detected in any samples of stormwater runoff
or drainage-well inflow.

        Pesticides, especially diazinon, malathion, and 2,4-D, were the most frequently detected organic
compounds in stormwater runoff, drainage-well inflow, and Floridan aquifer system water samples. The
priority pollutant bis(2-ethylhexyl)phthalate was detected in seven samples from five sites, probably
because of widespread use of the compound in plastic products. Polynuclear aromatic compounds
(fluoranthene, pyrene, anthracene, and chrysene) were found in stormwater runoff or inflow to drainage
wells at Lake Midget or Park Lake and may be associated with runoff containing petroleum products.

        Estimated annual loads to the Floridan aquifer system through drainage-well inflow in the
Orlando area, in pounds, are dissolved solids, 32,000,000; total nitrogen,  100, 000; total phosphorus,
13,000; total recoverable lead, 2,300; and total recoverable zinc, 3,700.


Goldschmid, J.  "Water-Quality Aspects Of Ground-Water Recharge  In Israel."  Journal Of The
American Water Works Association. V. 66, n. 3.  pp. 163-166.  1974.

        Abstract.   Because of the difference in rainfall and water needs in northern and southern
Israel, a method of recharging ground water and transporting it from the north to the south was needed.
This article details the new system, including problems encounter and overcome.


Goolsby, D. A. Geochemical Effects And Movement Of Injected Industrial Waste In A Limestone
Aquifer. Memoir No. 18. American Association Of Petroleum Geologists.  1972.

       Abstract.   Since 1963, more than 6 billion gal of acidic industrial waste has been injected into
a limestone aquifer near Pensacola, Florida.  The industrial waste, an aqueous solution containing nitric
acid, inorganic salts, and numerous organic compounds, is injected through two wells into the aquifer
between depths of 1,  400 and 1,700 ft (425-520 m). The aquifer receiving the waste is overlain by an
extensive clay confining layer which, at the injection site, is about 200 ft (60 m) thick.

        Industrial waste is presently (late 1971) being injected at a rate of about 2,100 gal per minute.
Wellhead injection pressures are about 175 psi. Calculations indicate that pressure effects in the
receiving aquifer extend out more than 30 mi (48 km).  No apparent change in pressure has been
detected in the aquifer directly above the clay confining layer. Geochemical effects were detected at a
monitor well in the receiving aquifer 0.25 mi (0.4 km) from the injection wells about 10 months after
injection began. The  geochemical effects included increases in calcium-ion concentration and total
alkalinity and formation of large quantities of nitrogen and methane gas.

       Geochemical effects have not been detected at monitor wells in the receiving aquifer 1.9 mi (3.0
km) north and 1.5 mi  (2.4 km) south of the injection wells, nor have effects been detected in a monitor
well at the injection site open to the aquifer directly overlying the clay confining layer. Tests made at the
injection wells early in 1968 indicated that rapid denitrification and neutralization of the waste occurred
near the injection wells. Denitrification may have accounted  for more than half neutralization, and
solution of calcium carbonate accounted for the rest. Denitrification has not been observed since mid-
1968, when the pH of the injected waste was lowered from 5.5 to 3.


Greene, G. E.  Ozone Disinfection And Treatment Of Urban Storm Drain Dry-Weather Flows: A
Pilot Treatment Plant Demonstration Project On  The Kenter Canyon  Storm Drain System In Santa
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Monica. The Santa Monica Bay Restoration Project, Monterey Park, CA. 1992.

        Abstract.   The Pico-Kenter Canyon storm drain has become the archetype for assessing the
problems and possible solutions that can be associated with many of the urban storm drains in the Santa
Monica Bay region.  While known events of chemical contamination are few, the drain has long been
known to be contaminated with indicator bacteria such as Total and Fecal Coliforms. More recently, the
consistent identification of Human Enteric Viruses, F-male Specific Coliphage, and high densities of
Enterococcus bacteria have indicated that a potentially serious public health threat exists.  The City Of
Santa Monica, with the assistance of the Santa Monica Bay Restoration Project (SMBRP), the United
States Environmental Protection Agency (EPA), and the UCLA Laboratory of Biomedical and
Environmental Sciences (LBES), recently completed an  evaluation of ozone for the treatment of dry-
weather storm drain flows. The primary goals of this study were to establish if ozone could be used to
disinfect the water that typically flows from the Pico-Kenter storm drain and determine if some known
hazardous chemical contaminants were present at significant levels.

        Recently, ozone has become renowned in the drinking water industry as an alternative to
chlorine that rapidly disinfects water while forming few halogenated by-products.  This study
demonstrated that ozone was an effective disinfectant, reducing bacterial and viral populations by 3-5
log (99.9 to 99.999% of the microbes killed or inactivated). In many of the 438 effluent samples,
coliform concentrations were sufficiently reduced to qualify the water for reclamation projects such as
landscape irrigation along the Santa Monica Freeway, suggesting a possible useful role for the treated
effluent. Ozonation by-products (aldehydes) were detected in the plant effluent at low (<100 PPB)
concentrations. No significant increase in halogenated by-products, or mutagenicity, were observed
following ozone disinfection. During a test of the ozonation process, twelve organic chemicals were
added to the influent water and the effluent monitored. While some refractory compounds passed
through the pilot facility  intact, the concentrations of most were reduced.

        In comparison to the State  Ocean Plan Water Quality Objectives and Federal Drinking Water
Maximum Contaminant Levels, the primary hazardous chemical constituents in the influent storm drain
water were metals (primarily copper and lead) and  polynuclear aromatic hydrocarbons (PAHs).  While
lead levels were significantly above both standards, the concentration of copper was well under drinking
water standards. The mean observed  level of six major PAHs were approximately equal to their
proposed phase V drinking water MCL standard  (100-400 ng/L or PPTr). Isolated samples were found to
contain organic contaminants, such as ortho-xylene and the pesticide chlordane. This did not appear to
be a pervasive problem and can be attributed to isolated events that cannot be anticipated and will only
be prevented through an informed and concerned public.

       While the metal content of the water cannot be reduced  using ozone, this study found that high
concentrations of some organics, including PAHs, can be reduced during the ozonation process. This
remediation probably occurs by oxidation and hydroxylation to less hazardous forms. Irregardless of
further ozonation investigations, additional more sensitive and definitive PAH analyses are warranted in
future studies of the storm drain water and sediments.

        Based on the results of this investigation, the City Of Santa Monica is investigating construction
of a disinfection facility that would reclaim high quality water for landscape irrigation, use low quality for
sewer flushing, and disinfect the remainder prior to releasing it into the Santa Monica Bay.  Construction
of the proposed facility would be encouraged by the support of the Santa Monica Bay Restoration Project
in goal definition and consensus building among the member and non-member agencies.
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                                     Summary Conclusions

1)   Ozone at moderate doses (10-20 mg/L) was an extremely effective disinfectant of dry-weather
storm drain flows.
2)   Bacterial and viral levels were reduced 3-5 log (99.9 to 99.999% of the microbes killed or
deactivated).
3)   Much of the effluent was sufficiently disinfected to meet the landscape irrigation standard of 23
coliforms per 100 ml.
4)   Based on California Ocean Plan Water Quality Objectives, heavy metals and polynuclear aromatic
hydrocarbons appear to be the primary contaminants of concern in the pilot plant effluent.
5)   While ozone disinfection by-products were detected (aldehydes), their concentration was low and, in
contrast to what would be expected from disinfection by chlorination, no increase in mutagenicity was
observed following ozonation.

                                  Summary Recommendations

1)   The SMBRP should encourage further evaluation of the ozone disinfection process, by promoting
the City of Santa Monica in its effort to design and construct a full scale facility.
2)   Since construction  and operation of the proposed facility will require interagency consent and
permitting, the City of Santa Monica solicits the continued assistance of the SMBRP in  consensus
building, policy direction, and technical support.
3)   Further investigations into the use of the ozone technology should include provisions for the
evaluation of Advanced Oxidation Processes (AOPs), using hydrogen peroxide and ozone, for the
control of organic pollutants such as PAHs.


Hampson,  P. S. Effects Of Detention On Water Quality Of Two Stormwater Detention Ponds
Receiving Highway Surface Runoff In Jacksonville, Florida. Geological Survey Water-Resources
Investigations Report 86-4151.  U.S. Geological Survey, Tallahassee, Florida.  1986.

       Abstract.   Water and sediment samples were analyzed for major chemical constituents,
nutrients, and heavy metals following 10 storm events at a stormwater detention ponds that receive
highway surface runoff in the Jacksonville, Florida, metropolitan area. The purpose of  the sampling
program was to detect changes in constituent concentration with time of detention within the pond
system. Statistical inference of a relation with total rainfall was found on the initial concentrations of 11
constituents and with antecedent dry period for the initial concentrations of 3 constituents.  Based on
graphical examination  and factor analysis,  constituent behavior with time could be grouped into five
relatively independent  processes for one of the ponds.  The processes were (1) interaction with shallow
ground-water systems, (2) solubilization of bottom materials , (3) nutrient uptake,  (4) seasonal changes in
precipitation, and (5) sedimentation.  Most of the observed water-quality changes in the ponds were
virtually complete within 3 days following the storm event.


Harper, H. H.  Effects Of Stormwater Management Systems On Groundwater Quality.  DER Project
WM190. Florida Department Of Environmental Regulation, Orlando, Florida. 1988.

       Abstract.   It has long been recognized that nonpoint sources of pollution contribute
significantly to receiving water loadings of both nutrients and toxic elements such as heavy metals
(Harper, 1983; Sartor,  et al., 1974).  As a means of protecting Florida surface waters from the effects of
nonpoint source pollution, the Florida Department of Environmental Regulation has established
regulations which require new developments or projects to retain or detain specified volumes of runoff
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water on-site.  In most cases runoff is collected in shallow ponds which infiltrate all or part of the retained
or detained volumes into groundwaters.

        When stormwater management facilities receive inputs of stormwater containing nutrients, heavy
metals and other pollutants, processes such as precipitation, coagulation, settling and biological uptake
deposit a large percentage of the input mass into the sediments. Recently, concern has been expressed
that this continual accumulation of pollutants in the sediments of stormwater management ponds may
begin to present a toxicity or pollution potential to  underlying groundwaters.  Specifically, do these
pollutant accumulations cause physical and chemical changes to occur within the sediments of
stormwater management facilities which mobilize  certain pollutant species from the sediment phase into
the water phase.


Mickey, J. J. "Subsurface Injection Of Treated Sewage Into A Saline-Water Aquifer At St.
Petersburg, Florida-Aquifer Pressure Buildup." Ground Water. V. 22, n. 1. pp. 48-55.  1984.

        Abstract.   The city of St. Petersburg has been testing subsurface injection of treated sewage
into the Floridan aquifer as a means of eliminating discharge of sewage to surface waters and as a
means of storing treated sewage for future nonpotable reuse.  The injection zone originally contained
native saline ground water that was similar in composition to sea water.  The zone has a transmissivity of
about 1.2 X 106 feet squared per day (ft^/ d) and is within the  lower part of the  Floridan aquifer.

        Treated sewage that had a mean chloride concentration of 170 milligrams per liter (mg/l) was
injected through a single well for 12 months at a mean rate of  4.7 X 10^ cubic feet per day (ft^/d). The
volume of water injected during the year was 1.7X10^ cubic feet.

        Pressure buildup at the end of one year ranged from less than 0.1  to as much as 2.4 pounds per
square inch (Ib/ in^) in observation  wells at the site.  Pressure buildup in wells open to the upper part of
the injection zone  was related to buoyant lift acting on the mixed water in the injection zone in addition to
subsurface injection through the injection well.

        Calculations of the vertical  component of pore velocity in the semiconfining bed underlying the
shallowest permeable zone of the Floridan aquifer indicate upward movement of native water. This is
consistent with the 200-to 600-mg/l increase in chloride concentration observed in water from the
shallowest permeable zone during the test.


Mickey, J. J. and  J. Vecchioli. Subsurface Injection of Liquid Waste With  Emphasis on Injection
Practices In Florida.  Geological Survey Water-Supply Paper 2281. United States Government
Printing Office, Washington D.C. 1986.

       Abstract.   Subsurface injection of liquid waste is used as a disposal method in many parts of
the country.  It is used particularly when other methods for managing liquid waste are either not possible
or too costly.  Interest in subsurface injection as a waste-disposal method stems partly from recognition
that surface disposal of liquid waste may establish a potential for degrading freshwater resources.
Where hydrogeologic conditions are suitable and where surface disposal may cause contamination,
subsurface injection is considered an attractive alternative for waste disposal. Decisions to use
subsurface injection need to be made with care because, where hydrogeologic  conditions are not suitable
for injection, the risk to water resources, particularly ground water, could be great. Selection of
subsurface injection as a waste-disposal method requires thoughtful deliberation and, in some instances,
extensive data collection and analyses.
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       Subsurface injection is a good geological method of waste disposal. Therefore, many State and
local governmental officials and environmentally concerned citizens who make decisions about waste-
disposal alternatives may know little about it. This report serves as an elementary guide to subsurface
injection and presents subsurface injection practices in Florida as an example of how one State is
managing injection.


Mickey, J. J. and W.  E. Wilson. Results Of Deep-Well Injection Testing At Mulberry, Florida.
Geological Survey Water-Resources Investigations Report 81-75. U.S. Geological Survey,
Tallahassee, Florida. 1982.

       Abstract.  At the Kaiser Aluminum and Chemical Corporation plant, Mulberry, Florida, high-
chloride, acidic liquid wastes are injected into a dolomite section at depths below about 4,000 feet below
land surface.  Sonar caliper logs made in April 1976 revealed a solution chamber that is about 100 feet
in height and has a maximum diameter of 23 feet in the injection zone.

       Results of two injection tests in 1972 were inconclusive because of complex conditions and the
lack of an observation well that was open to the injection zone.  In 1975, a satellite monitor well was
drilled 2,291 feet from the injection well and  completed open to the injection zone. In April 1975 and
September 1976, a series of three injection tests were performed.  Duration of the tests ranged from 240
to 10,020 minutes and injection rates ranged from 110 to 230 gallons per minute.  Based on an
evaluation of the factors that affect hydraulic response, water-level data suitable for interpretation of
hydraulic characteristics of the injection zone were identified to occur from 200 to 1,000 minutes during
the 10,020-minute test. Test results indicate that leakage through confining beds is occurring.

       Transmissivity of the injection zone was  computed to be within the range  from 700 to 1, 000 feet
squared per day and storage coefficient of the injection zone was computed to be within the range from
4x10~5 to 6x10~5. The confining bed accepting most of the leakage appears to be the underlying bed.
Also, it appears that the overlying beds are probably relatively impermeable and significantly retard the
vertical movement of  neutralized waste effluent.
Higgins, A. J. "Impacts On Groundwater Due To Land Application Of Sewage Sludge."  Water
Resources Bulletin.  V. 20, n. 3. pp. 425-434. 1984.

       Abstract.   The project was designed to demonstrate the potential benefits of utilizing sewage
sludge as a soil conditioner and fertilizer on Sassafras sandy loam soil. Aerobically digested, liquid
sewage sludge was applied to the soil at rates of 0, 22.4 and 44.8 Mg of dry solids/ha for three
consecutive years between 1978 and 1981. Groundwater, soil, and crop contamination levels were
monitored to establish the maximum sewage solids loading rate that could be applied without causing
environmental deterioration. The results indicate that application of 22.4 Mg of dry solids/ha of sludge is
the upper limit to  ensure protection of the groundwater quality on the site studied. Application rates at or
slightly below 22.4 Mg of dry solids/ha are sufficient for  providing plant nutrients for the dent corn and rye
cropping  system utilized in the study.


Horsley,  S. W. and J. A. Moser.  "Monitoring Ground Water For Pesticides At A Golf Course - A
Case Study On Cape Cod, Massachusetts." Ground Water Monitoring Review. V. 10. pp. 101-
108.  1990.
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       Abstract.   The town of Yarmouth, Massachusetts, proposed to locate a new municipal golf
 course within a delineated area of recharge to public water-supply wells. Two concerns of town officials
 were (1) hydrologic impacts upon downgradient wells; and (2) water- quantity impacts from fertilizers and
 pesticides. In response to these concerns, a thorough hydrogeologic investigation was made, fertilizer
 and pesticides management programs were recommended, and a ground water monitoring program was
 developed.

       The golf course parcel was determined to be underlain by a sand and gravel aquifer composed
 primarily of glacial outwash. Water-table maps confirmed that ground water flow was in the direction of
 several public water-supply wells. A three-dimensional finite-difference flow model was used to
 determine the optimum location and pumping rates for irrigation wells.  Potential nitrate-nitrogen
 concentration in the ground water were predicted to range from 5.0 to 7.9 milligrams per liter so slow-
 release fertilizers were recommended.

       With the assistance of the EPA Office of Pesticide Programs, the list of proposed pesticides was
 reviewed and sorted into three categories based on the known teachability,  mobility, and toxicity
 characteristics of each compound.  Specific recommendations were made as to pesticide selection and
 application rate using that classification.

       A  monitoring program was developed to provide an on-going assessment of any effects on water
 quality related to the application of fertilizer or pesticide.  The elements of the monitoring program
 include (1) specifications for monitoring wells and  lysimeters, (2) a schedule for sampling and analysis,
 (3) specific concentrations of nitrates or pesticide compounds that require resampling and analysis,
 restriction  of usage, or remedial action, and (4) regular reports to the Yarmouth Water Quality Advisory
 Committee and to the Yarmouth Water Department.  In a effort to ensure the implementation of this
 program, a table of responsibilities was prepared,  and a Memorandum  of Understanding adopting the
 program was signed by the town agencies interested in water-supply protection and the golf course
 operation.

       The monitoring facilities were installed with minimal problems as part of the golf course
 construction tasks.  However, implementation of the sampling and analysis part of the program was
 accomplished only after some difficulty and delay. The assistance of the State  Pesticide Bureau, the
 University  of Massachusetts Department of Entymology, and the Massachusetts Pesticide Laboratory
 was enlisted when budgetary problems threatened to prevent implementation. It is apparent from
 Yarmouth's experience that the mere preparation of a plan is not sufficient by itself.  Consultants who
 prepare the plan should make every possible effort to include implementation in their scope of services.


 Hull, R. W. and M. C. Yurewicz. Quality Of Storm Runoff To Drainage Wells In Live Oak,  Florida,
 April 4, 1979.  Geological Survey Open-File  Report 79-1073.  U.S. Government Printing Office,
 Washington, D.C.  1979.

       Abstract.    Water-quality samples of storm runoff to drainage wells were collected during a
 storm event on April 4, 1979.  Two sites in commercial areas and two in residential  areas of Live Oak,
 Florida, were sampled. A composite rainfall sample was collected from these sites, and rainfall quantity
 data were  obtained from two additional sites.

       Samples of storm runoff were analyzed for those constituents important to the potability of
water. The analyses generally included filtered and  unfiltered nutrients, bacteria, trace elements, and
organics.  Several of the analyses had constituent values which equaled or  exceeded maximum
containment levels for State primary drinking water standards and Federal proposed secondary drinking
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water standards.
Ishizakl, K.  "Control Of Surface Runoff By Subsurface Infiltration Of Stormwater: A Case Study
In Japan." Artificial Recharge Of Groundwater.  Butterworth Publishers, Boston,  pp. 565-575.
1985.

       Abstract.   Even though the annual rainfall in Japan is about 1,800 mm, which is twice as much
as the average rainfall worldwide, water shortages often occur during the summer months. This is
because a large amount of surface water is diverted to flood rice fields and, as a result, river flow is
reduced to the minimum.

       There have been various long-term national programs for the development and management of
water resources. Groundwater provides approximately 16 percent of the water resources requirements in
Japan. In some areas, however, the groundwater levels have been lowered by excessive pumping and
such problems as land subsidence and seawater intrusion have occurred. There have been many cases,
particularly in the coastal regions, where salinity of groundwater has become too high for any significant
beneficial uses.  In addition, due to the urbanization of river drainage basins in many parts of Japan, the
decrease of soil infiltration has caused excessive surface runoff, leading to several serious flooding
incidences in the surrounding areas.

       To reduce excessive surface runoff and to promote groundwater recharge of stormwater, a
number of groundwater recharge methods have been investigated at the Japan Ministry Of
Construction's Public Works Research Institute. This chapter describes the subsurface infiltration of
stormwater through culverts and also discusses the effects of the stormwater infiltration experiment at an
apartment complex in Tokyo, Japan.


Jansons, J., L.  W. Edmonds, B. Speight and M. R. Bucens. "Movement Of Viruses After Artificial
Recharge."  Water Research. V. 23, n. 3.  pp. 293-299. 1989a.

       Abstract.   Results of human enteric virus movement through soil and groundwater aquifers
after artificial recharge using wastewater are presented. The penetration through the recharge soil of
indigenous viruses from treatment plant effluent was found to be much greater than that of a seeded
vaccine poliovirus. Echovirus type 11 from wastewater was detected at a depth  of 9.0 m in groundwater
from a bore located 14m from the recharge basin whereas seed poliovirus was not isolated beyond a
depth of 1.5m below the recharge basin.  It was concluded that data on enteric virus survival in
groundwater were required if safe abstraction distances were to be determined.


Jansons, J., L.  W. Edmonds, B. Speight and M. R. Bucens.  "Survival Of Viruses In
Groundwater." Water Research. V. 23, n. 3.  pp. 301-306. 1989b.

       Abstract.   Survival in groundwater of echovirus types 6, 11  and 24, coxsackievirus type B5
and poliovirus type 1 was determined. Enterovirus survival in groundwater was found to be variable and
appeared to be influenced by a number of factors: temperature, dissolved oxygen concentration and
possibly the presence of microorganisms.  Dissolved oxygen concentration was the most significant
factor in loss of virus in groundwater.  Poliovirus type 1  incubated in groundwater with a mean dissolved
oxygen concentration of 2.0 mg/l decreased in infectivity by 100-fold in 50 days compared with 20 days
for a decreases of the same magnitude when incubated in groundwater with a mean dissolved oxygen
concentration of 5.4 mg/l.  Echovirus type 6 was found to be least stable, and poliovirus type 1 was found
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to be most stable, although virus stability may have been due to conditions existing in individual
groundwater bores.


Johnson, R. B.  "The Reclaimed Water Delivery System And Reuse Program For Tucson,
Arizona." Irrigation Systems For The 21st Century, Portland, Oregon, 1987. (American Society Of
Civil Engineers, New York, New York, pp. 344-351). 1987.

        Abstract.   The City of Tucson has implemented a reclaimed water reuse program in a
community-wide effort to preserve high quality groundwater for potable and other priority uses.
presently, the system consists of an 8.2 million gallons per day (mgd) pressure filtration plant
(expandable to 25 mgd), a 3 million gallon reservoir, a 12 mgd booster facility, and a significant network
of large capacity distribution lines which supply major turf irrigation uses throughout the community.  An
additional element of the system is a  1.0 mgd aquifer recharge facility which provides cost effective
seasonal storage of reclaimed water for subsequent recovery and use during the peak demand season.

        The initial system was made operational in February, 1984 with the first deliveries of  reclaimed
water for turf irrigation.  By the end of fiscal year 1986-87, Tucson Water will be providing nearly 5,000
acre feet per year of reclaimed water  with the expanding  reclaimed water system. It is projected that by
1995, Tucson's reclaimed water delivery system will be serving 35,000 acre feet for turf irrigation, cooling
tower and gravel washing uses throughout the metropolitan area.  The program has  reduced peak
demands on the potable water system and represents a major step toward  the efficient management of
the water resources available to our growing community.


Karkal, S. S. and D. L. Stringfield. "Wastewater Reclamation And Small Communities:  A Case
History."  Water Environment Federation 65th Annual Conference & Exposition, New Orleans,
Louisiana, 1992.  (Water Environment Federation, Alexandria, Virginia, pp. 419-425).  1992.

        Abstract.   In California's Central Valley, regulatory requirements and concerns of the local
community have led to a unique wastewater reclamation  project.  The City  of Orange Cove owns and
operates a 3,785.4 M^/day(1.0 mgd) treatment plant that uses tertiary treatment to produce a  high quality
reclaimed water that meets the California Code of Regulations (CCR) Title  22 requirements for
unrestricted irrigation  use.  The water is supplied to the independently own and operated Orange Cove
Irrigation District (OCID). This facility is in stark contrast to many  reclaimed wastewater irrigation
facilities in the Central Valley that use primary or secondary  effluents for irrigation. The objective of this
paper is to discuss the regulatory requirements leading to this project, and the factors involved in the
selection of the treatment processes used to meet these requirements.


Katopodes, N. D. and J. H. Tang. "Self-Adaptive Control Of Surface Irrigation Advance." Journal
Of Irrigation And Drainage Engineering. V. 116, n. 5.  pp. 696-713. 1990.

        Abstract.  The controllability of surface irrigation is examined by analytical means and
numerical tests based  on the linearized zero- inertia model.  First, the inflow hydrograph is proved  to be
identifiable from advance data. Then, it is shown that it is possible to control the advance rate by
adjustment of the inflow rate.  Field parameter heterogeneities are automatically  taken into account, so a
predetermined advance trajectory is obtained under arbitrary field conditions. The model utilizes a
tentative time increment, during which a trial value for inflow is adopted. The resulting wave advance is
simulated by the zero-  inertia model.  Discrepancies between the actual and desired advance  rate  are
then used to construct an objective function, whose minimization leads to a correction of the inflow rate
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for the next time increment of inflow. Finally, examples of self- adaptive control are presented, in which
an irrigation stream is led into a field of unknown parameters.  The model uses real-time information for
the identification of the parameters and simultaneous control of the inflow rate to achieve a desired
advance rate.
Kaufman, M. I. "Subsurface Wastewater Injection, Florida."  Journal Of Irrigation And Drainage
Engineering.  V. 99, n. 1. pp. 53-70.  1973.

       Abstract.   The Secretary of the Interior directed the U.S. Geological Survey in December,
1969 to begin a research program to evaluate the 'effects of underground waste disposal on the Nation's
subsurface environment, with particular attention to ground-water supplies.' The directive noted the
complexity of the subsurface environment and emphasized the need to begin collecting pertinent
environmental data.

       As a direct result, the Survey is engaged in an investigative and research program to develop a
scientific basis for assessing the long-term environmental impact of subsurface waste injection.
Prediction of movement, chemical interaction, and ultimate fate of injected liquid waste is difficult. As
noted by Piper: "Uncritical acceptance (of deep well injection) would be ill advised."  The complexity of
both the waste and the subsurface environment preclude making generalizations; with the present state
of knowledge, a thorough regional and localized study must be made for each proposed waste-injection
system.

       Extensive areas in Florida are underlain by deep permeable saline-aquifer systems that are
separated from overlying freshwater aquifers by low- permeability confining materials consisting of clay,
evaporites, or dense carbonate rocks.

       To resolve problems of waste disposal and to alleviate deterioration of fresh and estuarine
waters, approaches such as deep-well injection of industrial and municipal effluents into these saline-
aquifer systems are being actively explored.

       The hydrologic and geochemical characteristics of these saline-aquifer systems and their
response to waste injection are the subject of current research by the Survey. This information would
assist planning-management and regulatory agencies in their evaluation of subsurface injection  of liquid
wastes, including its potential applicability to regional water and waste management systems.

       This paper contains both a summary of data and present status of subsurface waste  injection in
Florida, including observed hydraulic and geochemical effects and  a descriptive regional portrayal of the
lithology and hydrogeochemistry of the saline-aquifer system.


Knisel, W. G. and  R. A. Leonard.  "Irrigation Impact On Groundwater:  Model Study In Humid
Region ."  Journal Of Irrigation And Drainage Engineering.  V.  115, n. 5. pp. 823-839.1989.

       Abstract.   The Groundwater Loading Effects of Agricultural Management Systems (GLEAMS)
model was applied to estimate the effects of:  (1) Soil; (2) planting date;  (3)  irrigation level; and (4)
pesticide characteristic on pesticide leaching below the root zone of representative coarse-grained soils.
Climate/application/pesticide-characteristic interactions are shown to significantly affect pesticide losses,
whereas  irrigation practice has little effect. Persistent and mobile compounds exhibit the highest losses.
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Krawchuk, B. P. and B. G. R. Webster. "Movement Of Pesticides To Ground Water In An Irrigated
Soil."  Water Pollution Research Journal Of Canada.  V. 22, n. 1.  pp. 129-146.  1987.

       Abstract.   The movement of pesticide residues to ground water was studied on a commercial
farm southwest of Portage la Prairie, Manitoba. The site  had sandy soil with low organic matter content,
a high water table, a tile drain system and an irrigation system using river water. Records were available
from the beginning of commercial operation in 1979 describing pesticide usage on a field by field basis.
A total of 21  different pesticide formulations were used in the 5 years of operation.

       An initial (1981) random sampling of the tile drain water did not detect any pesticide residues in
the outflow at the 0.02 ug/L level. A subsequent extensive sampling (1982) detected residues of
chlorothalonil on eight occasions ranging from 0.06 to 3.66 ug/L in the tile drain outflow. Ground water
from one of two wells in the northwest quarter was found  to contain chlorothalonil at a level of 10.1 to
272.2 ug/L in 1982 and 0.4 to 9.0 ug/L in 1983, carbofuran at a level of 11.5 to 158.4 ug/L in 1982 and
<0.5 to 1.0 ug/L in 1983, and carbofuran phenol (not quantified) in 1982 and 1983.

       RP-HPLC Kow data indicated that a number of the pesticides  used on the farm could be as
mobile or more mobile than chlorothalonil which had been detected in  the ground water in two
consecutive years; however, of the other pesticides only carbofuran was detected in the ground water.
With a Kow lower than that of chlorothalonil, carbofuran was expected to be more mobile than
chlorothalonil, and to appear in the water sooner, but this  was not observed in the field samples.


Ku, H. F. H., N. W. Hagelin and H. T. Buxton.  "Effects Of Urban Storm-Runoff Control On Ground-
Water Recharge In Nassau County, New York." Ground Water. V. 30, n. 4.  pp. 507-513. 1992.

       Abstract.   Before urban development, most ground-water recharge on Long Island, New York,
occurred during the dormant season, when evapotranspiration is low.  The use of recharge basins for
collection and disposal of urban storm runoff in Nassau County has enabled ground-water recharge to
occur also during the growing season.  In contrast, the use of storm sewers  to route storm runoff to
streams and coastal  waters has resulted in a decrease in  ground-water recharge during the dormant
season. The net result of the these two forms of urban storm-runoff control has been an increase in
annual recharge of about 12 percent in  areas served by recharge  basins and a decrease of about 10
percent in areas where runoff is routed to streams and tidewater. On a countrywide basis, annual ground-
water recharge has remained nearly the same as under predeveloped conditions, but its distribution
pattern has changed. Redistribution resulted in increased recharge in  the eastern and central parts of the
county, and decreased  recharge in the western and near shore areas. Model simulation of recharge
indicates that the water- table altitude has increased by as much as 5 feet above predevelopment levels
in areas served by recharge basins and declined by as much as 3 feet in areas where  stormwater is
discharged to streams and tidewater.


Ku, H. F. H.  and D. L. Simmons.  Effect Of Urban Stormwater Runoff On Ground Water Beneath
Recharge Basins On Long Island, New York.  Geological  Survey Water-Resources Investigations
Report 85-4088. U.S. Geological Survey, Syosset, New York. 1986.

       Abstract.   Urban stormwater runoff was monitored during 1980-82 to investigate the source,
type, quantity, and fate  of contaminants routed to the more than 3,000 recharge basins on Long Island
and to determine whether this r>  off might be  a significant source of contamination to the ground-water
reservoir.  Forty-six storms were monitored at five recharge basins in representative land-use areas (strip
commercial,  shopping-mall parking lot,  major highway, low-density residential, medium-density
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residential).

       Runoff/precipitation ratios indicate that all storm runoff is derived from precipitation on
impervious surfaces in the drainage area except during storms of high intensity or long duration, when
additional runoff can be derived from precipitation on permeable surfaces.

       Concentrations of most measured constituents in individual stormwater samples were within
Federal and State drinking-water standards. The few exceptions  are related to specific land uses and
seasonal effects.  Lead was present in highway runoff in concentrations up to 3,300 micrograms per liter
(ug/L), and chloride was found in parking-lot runoff in concentrations up to 1,100 milligrams per liter
(mg/L) during winter, when salt is used for deicing.

       The load of heavy metals was largely removed during movement through the unsaturated zone,
but chloride was not removed. Total nitrogen was commonly found in greater concentrations in ground
water than in stormwater; this is attributed to seepage from cesspools and septic tanks and to the use of
lawn fertilizers.

       In the five composite stormwater samples and nine ground-water grab samples that were
analyzed for 113 U.S. Environmental Protection Agency-designated "priority pollutants," four constituents
were detected in concentrations exceeding New York State guidelines of 50 ug/L for an individual
organic compound in drinking water:  p-chloro-m-cresol (79 ug/L in ground water at the highway basin);
2,4-dimethylphenol (96 ug/ L in ground water at the highway basin); 4-nitrophenol (58 ug/L in ground
water at the parking-lot basin); and methylene chloride (230 ug/L in stormwater at the highway basin).
One stormwater sample and two ground-water samples exceeded New York State guidelines for total
organic compounds in  drinking water (100 ug/ L). The presence of these constituents is attributed to
contamination from point sources rather than to quality of runoff from urban areas.

       The median number of indicator bacteria in stormwater ranged from 10^ to 10^ MPN/100 mL
(most probable  number per 100 milliliter). Fecal coliforms and fecal streptococci increased buy 1 to 2
orders of magnitude during the warm season.  Total coliforms concentrations showed no significant
seasonal differences.

       Low-density residential and nonresidential (highway and parking lot) areas contributed the fewest
bacteria to stormwater; medium-density residential and strip commercial areas contributed the most. No
bacteria were detected in the ground water beneath any of the recharge basins.

       The use of recharge basins to dispose of storm runoff does not appear to have significant
adverse effects  on ground-water quality in terms of the chemical and microbiological stormwater
constituents studied.
Ku, H. F. H., J. Vecchioli and S. E. Ragone. "Changes In Concentration Of Certain Constituents
Of Treated Waste Water During Movement Through The Magothy Aquifer, Bay Park, New York."
Journal Research U.S. Geology Survey. V. 3, n. 1. pp. 89-92. 1975.

       Abstract.   Approximately 7 million gallons (27 million litres)  of tertiary- treated sewage
(reclaimed water) was injected by well into the Magothy aquifer and was subsequently pumped out. As
the reclaimed water moved through the aquifer, concentrations of certain dissolved constituents
decreased as follows: Total nitrogen, 7 percent; methylene blue active substances, 49 percent; chemical
oxygen demand, 50 percent; and phosphate,  more than 93 percent.
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Lauer, D. A.  "Vertical Distribution In Soil Of Sprinkler-Applied Phosphorus." Soil Science
Society Of America Journal. V. 52, n. 3.  pp. 862-868. 1988a.

       Abstract.   Soil-immobile plant nutrients, such as P, accumulate near the soil surface in
conservation cropping systems where tillage leaves crop residues on or near the soil surface and limits
soil mixing. The objective was to determine, in field and laboratory experiments, the vertical distribution
in soil of P applied in sprinkler irrigation water.  Following P applications, distribution was determined
from depth increment (1 or 2 cm) sampling  on  a Warden silt loam (coarse-silty, mixed, mesic, Xerollic
Camborthids) and a Quincy sand (mixed, mesic, Xeric Torripsamments). The fertilizer materials applied
in 10-mm irrigations were: monoammonium phosphate (227g P kg'1), urea phosphate (192g P kg'1),
commercial white phosphoric acid (238g P kg'1), and ammonium polyphosphate (149g P kg"1)
containing 61 g P kg"1 as polyphosphate.  Application  rates ranged from 50 to 400 kg P ha"1. Movement
of P was about the same for all P fertilizer materials except ammonium polyphosphate, from which P
moved only 60 to 70% of the depth of the other materials. Postapplication irrigation totals up to 160 mm
at 10 m d1, which was applied without drying cycles, distributed P more uniformly with depth. The
overall mean depths of P penetration across all treatments were 10.4 cm (SD = 4.04 cm) on the Quincy
sand and 7.3 cm (SD = 4.93 cm)  on the Warden silt loam. Theses depths of penetration and vertical
distribution of sprinkler-applied P are probably  sufficient to supply the P needs of crop  plants under
sprinkler irrigation. .


Lauer, D. A.  "Vertical Distribution In Soil Of Unincorporated Surface-Applied Phosphorus Under
Sprinkler Irrigation."  Soil Science Society Of America Journal.  V. 52, n. 6.  pp. 1685-1692. 1988b.

       Abstract.    Determining vertical distribution of P is important  in irrigated conservation cropping
systems for evaluation of P fertilization because soil-immobile phosphorus accumulates near the soil
surface where limited tillage reduces soil mixing.  The objective was to determine in field and laboratory
experiments the vertical distribution of P from surface -applied monoammonium phosphate (MAP; 227 g
P kg"1), triple superphosphate (TSP; 197 g P kg"1) and ammonium polyphosphate (APP; 149g P kg"1).
Following P application, vertical distribution was determined from 2-cm depth increment samples in a
Quincy sand (mixed, mesic, Xeric Torripsamments), a Warden silt loam (coarse-silty, mixed, Xerollic
Camborthids), and a calcareous subsoil of the  Warden.  There was little effect on P distribution from
antecedent moisture; fertilizer rates at 30, 60, 120, or 240 kg P ha"1; or from preirrigation reaction times
of 1, 4, or 16 d.  Continuous postapplication irrigation totals of 40 or 160 mm at 10 mm d"1 moved P
somewhat deeper into the soil, principally at 160 mm on the Quincy sand. Overall mean penetration
depths of P were as follows:  (i) APP moved the farthest in the Quincy sand (mean = 6.1; SD = 1.05 cm);
(ii) penetrations were practically the same for MAP or TSP on the Quincy sand (mean  = 5.5; SD = 1.25
cm); (iii) depth of penetration was intermediate  for APP on the noncalcareous Warden (mean = 4.0; SD
= 0.98 cm); and (iv) downward movement in calcareous Warden of P from all fertilizer P materials was
much more restricted (MAP/TSP: mean = 3.1;  SD = 0.10 cm and APP: mean = 3.3; SD = 0.52) than on
the two noncalcareous soils.  Overall, the most apparent conclusion from this study is that the reactivity
of P fertilizer material with the soil is the dominant and overriding determinate of the vertical distribution
of surface-applied  P.


Lee, E. W.  "Drainage Water Treatment And  Disposal Options."  Agricultural Salinity Assessment
And Management. American Society Of Civil Engineers,  pp. 450-468. 1990.

       Abstract.   Treating and disposing of  subsurface drainage water from irrigated agricultural
lands presents unique technical challenges.  A  review of the literature reveals limited experiences in the
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management of such waters. The challenge is made more difficult by the complex chemical
characteristics of most drainage water. Drainage usually contains a heavy salt load -- a perennial cause
for concern -- and residual pesticides, herbicides, fungicides, fertilizers and toxic trace elements -- a
more recent cause for concern. While crop management practices and conventional treatment
processes can control salt and residuals to some degree, a new treatment technology needs to be
developed to control toxic trace elements. Conventional methods appear to be ineffective in meeting the
requirements set by many regulatory agencies.

       In this chapter, the treatment and disposal of subsurface drainage from irrigated lands will be
covered, disposal options will be presented, the technology of drainage water treatment and disposal
options will be reviewed, and current research on treatment technology will be discussed.


Lloyd, J. W., D. N. Lerner, M. O. Rivett and M. Ford.  "Quantity And Quality Of Groundwater
Beneath An Industrial Conurbation - Birmingham, UK." Hydrologlcal Processes And Water
Management In Urban Areas, Dulsburg, Federal Republic Of Germany, 1988. (International
Hydrological Programme, UNESCO, pp. 445-453).  1988.

       Abstract. Since the 1960's groundwater heads have been rising  noticeably beneath
Birmingham, principally due to reducing abstraction. Despite the almost complete urbanisation of the
aquifer surface,  potential recharge is at least as  high as it was before the  city was built. There is
sufficient leakage from water mains and sewers to make up for the reduced infiltration at the surface.
The marked change in groundwater conditions has prompted interest in groundwater quality and both
inorganic and organic quality of the groundwater are currently being studied. First indications are of
widespread worsening inorganic quality, with high nitrates, chlorides and certain trace elements.
Chlorinated organic solvents (e.g. trichloroethylene) are widespread, but there is little evidence to date of
other organic pollutants.


Lon, P. C., R. S. Fujioka and W. M. Hirano. "Thermal Inactlvation Of Human Enteric Viruses In
Sewage Sludge And Virus Detection By Nitrose Cellulose-Enzyme Immunoassay." Chemical And
Biological Characterization Of Sludges, Sediments, Dredge Spoils, And Drilling Muds. ASTM
STP976. American Society For Testing And  Materials, Philadelphia, Pennsylvania, pp. 273-281.
1988.

       Abstract.  The Zimpro Thermal Sludge Treatment Process installed at the Sand Island
Wastewater Treatment Plant, Honolulu,  HI, was evaluated for its reliability in disinfecting human enteric
viruses and fecal bacteria in the treated sludge.  The principle of this process involves grinding the
sludge particles to a small size(<4.8 mm) and heating the ground sludge to 193'C under 330 psi pressure
for 30 min.  Such thermally treated sludge yielded no  human enteric viruses and little or no fecal
bacteria(<2 to 24 MPN/100g), thus rendering the sludge safe for reuse. In corollary studies, the
nitrocelluose-enzyme immunoassay was evaluated as an alternate cost-effective method to augment
infectivity assays for the detection of human enteric viruses. The method was found to be rapid, highly
sensitive (it can detect picogram quantities), and specific for the detection of human enteric viruses.


Malik, A., M. Stone, F. R. Martinez and R. Paul.  "First Wastewater Desalting Plant In Central
Coast, California."  Water Environment Federation 65th Annual Conference & Exposition, New
Orleans, Louisiana, 1992.  (Water Environment Federation, Alexandria, Virginia, pp. 395-406).
1992.
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        Abstract.   This paper describes a 144.6 liter/second (Us) (3.0 million gallon per day (mgd))
 water reclamation plant and a 35 Us (0.8 mgd) reverse osmosis plant (RO). The water reclamation plant
 treats secondary treated discharged from the Goleta Sanitary District wastewater treatment plant. The
 RO plant further processes a portion of the effluent that will be produced at the water reclamation plant.
 RO treatment is needed to : (1) lower the chloride content of the tertiary effluent to less than 300
 milligrams per liter (mg/l), for protection of golf course greens and sensitive plants; and (2) to provide
 water with reduced concentrations of chlorides, sodium,  sulfates, and other constituents to agricultural
 growers.

        The installed RO  Plant will produce 35 U/s (0.8 mgd) of desalted water. The facility will
 discharge 9.6 Us (0.22 mgd) desalted water to the agricultural growers and discharge 25.4 Us (0.58
 mgd) to reclaimed water storage tanks for blending with  effluent from the water reclamation plant. 115.7
 Us (2.64 mgd) of blended effluent will be available to distribute to all other reclaimed water users.


 Mancinl, J. L. and A. H. Plummer Jr.  "A Method For Developing Wet Weather Water Quality
 Criteria for Toxics."  Water Environment Federation 65th Annual Conference & Exposition, New
 Orleans, Louisiana, 1992.  (Water Environment Federation, Alexandria, Virginia, pp. 15-26). 1992.

        Abstract.   Current federal and state water quality programs are focusing on control of toxics
 and on impacts from diffuse sources. These two elements of regulatory programs can be expected to
 come together in the future. Regulations will begin to address the effects of toxics from  diffuse sources.

        Diffuse sources of contaminants such as runoff from urban, industrial,  and agricultural sites are
 associated with wet weather events.  The inputs of toxic  materials from these sources are intermittent,
 and may not occur during all runoff events. Exposure of aquatic organisms to toxicants, from these
 sources, are often of short duration separated by extended periods which provide opportunities for
 organism recovery. The concentrations and exposure patterns of toxicants, which cause impacts on
 resident aquatic organisms are different, for diffuse wet weather dischargers and continuous point source
 inputs.

       The potential cost for control of toxics in discharges from diffuse sources is large.  Therefore, it is
 important that water quality criteria properly represents the level of protection needed to address
 contaminants introduced by diffuse sources.  The application of technologically-based modifications to
 existing water quality criteria which account for the characteristics of diffuse sources (e.g. wet weather
 inputs) could produce environmental protection at lower costs.

       This paper presents technology which could  be used to modify existing EPA numerical criteria
 for toxics to consider the effects of the variability of concentrations and exposure patterns associated
 with wet weather inputs.  Illustrations of criteria development, site-specific use of criteria and compliance
 monitoring are included. The technology can also be used to estimate the impacts of wet weather
 discharges on aquatic organisms.


 Markwood, I. M. "Waterborne Disease--Historical Lesson."  Ground Water. V. 17, n 2  pp  197-
 198. 1979.

       Abstract.   While it is true that waterborne diseases are still with us, and probably always will
 be, we cannot classify them as a current threat in the sense that they were 100 years ago. The discovery
that chlorine would  disinfect water supplies removed  these diseases from a "current threat" to a
"historical lesson" category.  We are not faced with unknown which we are unable to attack.  We have
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only to look at what others have done to protect themselves and follow the same or improved practices.

       If the record of waterborne outbreaks in public water supplies in this country from the end of
World War II up to the present is examined, it will be found that all are caused by breakdowns in
disinfection procedures or carelessness. The record is replete with statements such as "improper
disinfection after repair," "breakdown or lack of disinfecting equipment," "back siphonage," and other
similar statements all pointing to failure to follow practices which the history of water treatment has
shown to be necessary for protection against waterborne disease. Carelessness allows recurrence of
disease outbreaks. If the lessons of history were followed, the conquest of waterborne disease
transmission by public water systems could be  complete.


Mart on J. and Mohler I. "The Influence Of Urbanization On The Quality Of Groundwater."
Hydrological Processes And Water Management In Urban Areas, Duisburg, Federal Republic Of
Germany, 1988. (International Hydrological  Programme, UNESCO, pp. 452- 461).  1988.

       Abstract.   On the example of the described antropogeneous activities in an urbanized basin
we have manifested their influence upon quantitative and qualitative regime of groundwater on the
territory of Bratislava and the consequential measures taken to suppress or liquidate their negative effect
as well.
Marzouk, Y., S. M. Goyal and C. P. Gerba. "Prevalence Of Enteroviruses In Ground Water Of
Israel." Ground Water. V. 17, n. 5. pp. 487-491. 1979.

       Abstract.   Few studies have been performed on the occurrence of enterovirus contamination
of ground water.  In this study, 99 ground-water samples were examined for the presence of
enteroviruses, total bacteria, fecal conforms, and fecal streptococci by standard methods. Enteroviruses
were isolated from 20% of the samples. Viruses were isolated from 12 samples which contained no
detectable fecal organisms per 100 ml. No statistical correlation between presence of virus and
bacteriological indicators could be determined. The widespread failure of current bacteriological
standards to indicated the  presence of potentially pathogenic enteroviruses in ground water is an area of
concern that requires more study.


Merkel, B., J. Grossmann and P. Udluft.  "Effect Of Urbanization On A Shallow Quarternary
Aquifer."  Hydrological Processes And Water Management In Urban Areas, Duisburg, Federal
Republic Of Germany, 1988.  (International Hydrological Programme, UNESCO, pp. 461-469).
1988.

       Abstract.   Quantity and quality of groundwater renewal is mainly determined by physico-
chemical processes within the soil and the unsaturated zone. Pollution of groundwater from urbanization
were brought to light and exemplary pointed out by deposits from precipitation, sodium chloride
spreading and leakage from sewerage.


Mossbarger, W. A. Jr. and R. W. Yost.  "Effects Of Irrigated Agriculture On Groundwater Quality
In Corn Belt And Lake States." Journal of Irrigation and Drainage Engineering. V. 115, n. 5. pp.
773-789.  1990.

       Abstract.   The impact of irrigation on groundwater quality is influenced by climate, topography,
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geology, soils, geohydrology, crops, and agricultural practices. Since the early 1950s, the irrigated crop
acreage in the Corn Belt and Lake States has increased markedly.  Irrigation in these regions is
concentrated in areas underlain by sandy soils with low moisture-holding capacities, where supplemental
moisture and relatively heavy applications of agrichemicals are needed to achieve economically viable
crop yields.  Due to the  high hydraulic conductivities and low attenuation capacities of sandy soils,
shallow aquifers underlying these areas are particularly susceptible to contamination with nitrates and
stable, soluble pesticides. Present and potential problems associated with irrigation in these states are
illustrated by available case studies from the Central Sand Plain of Wisconsin.


Nellor,  M. H., R. B. Baird and J. R. Smyth. "Health Aspects Of Groundwater Recharge."  Artificial
Recharge Of Groundwater. Butterworth Publishers, Boston, pp. 329-355.  1985.

        Abstract.   Southern California,  like many semiarid regions of the United States, does not
receive  sufficient water from local sources to support the considerable population of the area. Almost two
thirds of the water supply is imported 200 to 500 miles from the point of use. The remainder is derived
from local groundwater basins.  In some areas, the occurrence of overdraft conditions and saltwater
intrusion has led to the adjudication of groundwater extractions and/or the implementation of artificial
groundwater replenishment. Water sources used for groundwater replenishment include storm runoff,
imported water, and, in some cases, treated wastewater (reclaimed water).

        There is considerable uncertainty at this time regarding the sufficiency of water supplies for
future water needs of the area.  Population growth projections coupled with reductions in imported water
deliveries indicate that, by the mid-1990s water needs may exceed available supplies. These water
shortage predictions have stimulated regional planning activities aimed at optimizing available water
supplies through conservation efforts and developing new local sources of supply through conjunctive
groundwater storage and water  reclamation.  Foremost among these planning efforts is the Orange and
Los Angeles Counties Water Reuse Study, which has identified the most viable water reclamation
projects within the South Coast  Region and  has developed a financial and institutional scheme for their
implementation. Of all the reclamation projects  under consideration, groundwater recharge represents
the largest and most economical use of reclaimed water.

        Despite these economic incentives,  implementation of proposed groundwater recharge projects
is constrained by concerns over the potential health impacts of indirect  reuse for potable purposes.
Health issues associated with groundwater recharge include the acute and chronic effects of trace
metals,  minerals, pathogens, and organic compounds that, if present in reclaimed water, may ultimately
become part of a potable water  supply. Available information on existing  groundwater recharge projects
has never shown any evidence of impaired water quality or health.  Yet, it is recognized that this
information is insufficient for rigorous evaluation of the possible long-term health implications associated
with indirect potable reuse.

        The existing groundwater recharge projects in Los Angeles and Orange  Counties provided an
opportunity to gather the data needed to evaluate the health significance of water reuse by groundwater
recharge.  Foremost among these is the Whittier Narrows groundwater recharge project located in the
Montebello Forebay area of Los Angeles County where planned replenishment using reclaimed water
has been practiced since 1962.  A work plan was developed by the Los Angeles County Sanitation
Districts, which incorporated multidisciplinary research recommendations  proposed by a "blue ribbon"
panel of experts convened by the California State Water Resources Control Board, the Department of
Water Resources, and the Department of Health Services. The work plan formed the basis for the
Health Effects Study that formally began  in November 1978 and was completed in March 1984.
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Nightingale, H. I., J. E. Ayars, R. L. McCormick and D. C. Cehrs. "Leaky Acres Recharge Facility:
A Ten-Year Evaluation."  Water Resources Bulletin. V. 19, n. 3. pp. 429-437.  1983.

       Abstract.   From 1971-1980, studies were conducted at Fresno, California, to identify and
quantity, where possible, the soil and water chemistry, subsurface geologic, hydrologic, biologic, and
operational factors that determine the long term (10 year) effectiveness of basin type artificial ground
water recharge through alluvial soils  This paper updates previous findings and refers to publication that
describe the geology beneath the basins and regional geology that determine the transmission and
storage properties for local ground water management and chemical quality enhancement.  High quality
irrigation water from the Kings River was used for recharge. Construction and land costs for the present
expanded facility 83 ha (205.2 ac) using three parcels of land were $1,457,100.  The nine-year annual
mean costs for only canal water, maintenance, and operation were $110.42/ ha*m ($13.62/ac*ft) based
on an average recharge rate of 1338 ha*m/yr (10,848 ac*ft/yr) at 86 percent facility efficiency. The
measured end of season recharge rate averaged 14.97 +. 0.24 cm/ day. The 10-year mean actual
recharge rate based on actual water delivered, total ponded area, and total days of recharge was 12.1
cm/day.


Nightingale, H. I. "Accumulation Of As, Ni, Cu, And Pb In Retention And  Recharge Basins Soils
From Urban Runoff." Water Resources Bulletin. V. 23, n. 4. pp. 663-672. 1987a.

       Abstract.   The accumulation of arsenic, nickel, copper, and lead in the soil profile was
determined beneath five urban storm-water retention/ recharge basins used by the Fresno Metropolitan
Flood Control District, California. Soils were  sampled from the surface to the first zone of saturation and
compared with soils from an adjacent uncontaminated control site. These elements were found to be
accumulating in the first few centimeters of basin soil and are important to the effectiveness of a specific
best management practice, i.e., the retention and recharge of urban storm water. Study basins in use
since 1962, 1965, and 1969 had lead contents in the 0-2 cm soil depth interval of 570, 670, and 1400 mg
Pb/kg soil, respectively. The median indigenous soil lead concentration was 4.6 mg/kg soil. The
practice of removing excess flood runoff water from two basins by pumping apparently is a factor in
reducing the accumulation rate of these elements in the surface soils of the basins.


Nightingale, H. I. "Water Quality Beneath  Urban Runoff Management Basins."  Water Resources
Bulletin. V. 23, n. 2. pp. 197-205. 1987b.

       Abstract.   The chemical impact of  urban runoff water on water quality beneath five
retention/recharge basins was investigated as part of the US  EPA's Nationwide Urban Runoff Program in
Fresno, California.  Soil water  percolating through alluvium soils and the ground water at the top of the
water table were sampled with ceramic/Teflon vacuum water extractors of depths up to 26m during the
two-year investigation. Inorganic and organic pollutants are present in the runoff water delivered to the
basins. No significant contamination of percolating soil water or ground water underlying any of the five
retention/recharge basins has occurred for constituents monitored in the study. The oldest basins was
constructed in 1962. The concentration of selected trace elements in the ground water samples was
similar to the levels reported in the regional ground water. None of the pesticides or other organic
priority pollutants, for which water samples were analyzed, was detected except diazinon which was
found in trace counts (0.3 ug/L or less) in only three soil water samples.  These results are important to
the continued conservation of storm water and the development of a best management practice for
storm-water management using retention/ recharge basins in a semi-arid climate.
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Nightingale, H. I. and W. C. Bianchi. "Ground-Water Chemical Quality Management By Artificial
Recharge."' Ground Water.  V. 15, n. 1.  pp. 15-22. 1977a.

       Abstract.   The effectiveness of basin ground-water recharge at the Leaky Acres Facility in
Fresno, California for improving the regional ground-water quality was studied as 65,815,000 m3 of high-
quality surface water was recharged from 1971 through 1975.  Observation wells at the facility showed
some variability in chemical parameters associated with each recharge period.  The long-term decrease
in salinity could be described by decay curve fitted by regression analysis.

       Without a special network of observation wells outside the facility,  scientific evaluation of the
enclave of recharged water is not possible.  A practical evaluation of water-quality changes is possible
from producing water wells around the facility.  However, the pumping well discharge-time variations,
well depth, aquifer sequence, and prior use of surrounding land must be considered, since all of these
factors affect the pumped-water quality and its seasonal variability.  Recharge at Leaky Acres had
noticeably decreased the ground-water salinity for a distance of up to 1.6 km in the regional ground-water
movement.


Nightingale, H. I. and W. C. Bianchi. "Ground-Water Turbidity Resulting From Artificial
Recharge."  Ground Water. V. 15, n. 2. pp. 146-152. 1977b.

       Abstract.   Turbid ground water is rarely observed in domestic or public supply aquifers. At the
Leaky Acres Recharge Facility at Fresno, California, water of low salinity(<50 umhos/cm) and turbidity
(<5 FTU, Formazin turbidity units)  is recharged in the spreading basins. Six months after the start of the
third (1973) recharge period, the groundwater salinity was decreased to about 100 umhos/cm from the
initial mean of 147 umhos/cm and the ground water became visibly turbid (>5 FTU)/ Two months later,
some peripheral domestic wells also began to become turbid. After two more recharge periods (1974
and 1975), turbidity at 10 observation wells beneath Leaky Acres averaged 18 FTU  and salinity averaged
74 umhos/cm.  By this time, ground-water turbidity in peripheral wells near  Leaky Acres had decreased
to <0.5 FTU. This turbidity was traced to poorly-crystallized and extremely fine colloids, which have
leached from the surface soils because of the low salinity of the recharge water. Laboratory  and field
studies showed that  gypsum application will reverse the phenomena, but such treatment is
uneconomical. This  phenomenon is a transient one, and now turbidity outside the recharge area is
insignificant from a water quality viewpoint.  However, the magnitude of the mass of material is transit
through the profile if  stabilized through flocculation or sieving in soil pore space, could greatly change the
water transmission and so recharge project performance.  However, we have not yet noted this effect at
Leaky Acres.


Norberg-King, T. J., E. J. Durhan, G. T. Ankley and E. Robert.  "Application Of Toxiclty
Identification Evaluation Procedures To The Ambient Waters Of The Colusa Basin Drain,
California."  Environmental Toxicology And Chemistry.  V. 10. pp. 891-900. 1991.

       Abstract.   Pesticides are applied to the rice fields in the Sacramento Valley to prevent the
growth of plants, algae and insects that reduce rice yields. Following the pesticide application, field water
is released into agricultural drains that in turn discharge into the Sacramento River and delta. Rice
irrigation is the largest single use of irrigation water in the Sacramento Valley, and because the irrigation
water (or rice return) flows are the primary source of drain effluent during the spring and summer (up to
33% of the total flow), these  discharges can significantly affect drain water quality and resident aquatic
organisms.  Acute and chronic toxicity to freshwater organisms (Ceriodaphnia dubia) was observed in
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the drain water during the period that coincides with the initial draining of the fields in 1986,  1987 and
1988.  In 1988, atoxicity identification evaluation (TIE) was conducted using Ceriodaphnia dubia in an
effort to identify the cause of toxicity. Both methyl parathion and carbofuran were identified  as possible
toxicants. Mixture tests and chronic toxicity tests indicated that the concentrations of methyl parathion
and carbofuran in the water sample account for the toxicity observed in Ceriodaphnia dubia.


Pahren, H. R. "EPA's Research Program On Health Effects Of Wastewater Reuse For Potable
Purposes." Artificial Recharge Of Groundwater.  Butterworth Publishers, Boston,  pp. 319-328.
1985.

        Abstract.   One of the many objectives of the Office of Research and Development of the U.S.
Environmental Protection Agency (EPA) has been to carry out a relatively small research program on the
potential health effects associated with the reuse of renovated wastewater for potable purposes. This
chapter reviews the research tasks conducted and the results obtained to date.

        Research on potable reuse was initiated in 1974 and the federal program funding averaged
about $400,000 annually through 1978.  Following the 1977 amendments to the Safe Water Drinking Act,
which called for special studies on the health implications involved in the reclamation, recycling, and
reuse of wastewaters for drinking, funds for reuse research increased. However, the separate program
on wastewater reuse was discontinued in 1981.  Any activity in the future will be continued as part of the
regular drinking water  base research program.


Peterson, D. A.  "Selenium In The Kendrick Reclamation Project, Wyoming." Planning Now For
Irrigation And Drainage In The 21st Century, Lincoln, Nebraska, 1988.  (American Society Of Civil
Engineers, New York, New York, pp. 678-685).  1988.

        Abstract.   Elevated concentrations of  selenium in water, bottom sediment, and biota were
noted during a reconnaissance investigation of the Kendrick Reclamation Project in central Wyoming.
Dissolved- selenium concentrations in 11 of 24 samples of surface or ground water exceeded the
national drinking-water standard of 10 micrograms per liter. Bottom-sediment samples contained
concentrations of several elements, including selenium, that were greater than baseline concentrations in
soils of western States. Samples of biota from several trophic levels at four wetlands contained selenium
at concentrations associated with physiological problems and abnormalities as reported in laboratory
studies and previously published literature.


Petrovic, A. M.  "The Fate Of Nitrogenous Fertilizers Applied To Turfgrass."  Journal Of
Environmental Quality. V. 19, n. 1.  pp. 1-14.  1990.

       Abstract.   Maintaining high quality surface and groundwater supplies is a national concern.
Nitrate is a widespread contaminant of groundwater.  Nitrogenous fertilizer applied to turfgrass could
pose a threat to groundwater quality.  However, a review of the fate of N applied to turfgrass is lacking,
but needed in developing management systems  to minimize groundwater contamination. The discussion
of the fate of N applied to turfgrass is developed  around plant uptake, atmospheric loss, soil  storage,
leaching, and runoff. The proportion of the fertilizer N that is taken up by the turfgrass  plant varied from
5 to 74% of applied N. Uptake was a function of N release rate N rate and species of grass.
Atmospheric loss, by either NH3 volatilization or  denitrification, varied from 0 to 93% of applied N.
Volatilization was generally <36%  of applied N and can be reduced substantially by irrigation after
application. Denitrification was only found to be  significant (93% of applied N) on fine-textured,
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saturated, warm soils. The amount of fertilizer N found in the soil plus thatch pool varied as a function of
N source, release rate, age of site, and clipping management. With a soluble N source, fertilizer N found
in the soil and thatch was 15 to 21% and 21 to 26% of applied N, respectively, with the higher values
reflecting clippings being returned. Leaching losses for fertilizer N were highly influenced by fertilizer
management practices (N rate, source, and timing), soil texture, and irrigation.  Highest leaching losses
were reported at 53% of applied N, but generally were far less than 10%.  Runoff of N applied to
turfgrass has been studied to a limited degree and has been found seldom to occur at concentrations
above the federal  drinking water standard for NC>3~. Where turfgrass fertilization poses a threat to
groundwater quality, management strategies  can allow the turfgrass manager to minimize or eliminate
NC>3~ leaching.


Phelps, G. G. Effects Of Surface Runoff And Treated Wastewater Recharge On Quality Of Water
In The Florldan Aquifer System, Gainesville Area, Alachua County, Florida . Geological Survey
Water-Resources Investigations Report 87-4099. U.S. Geological Survey, Tallahassee, Florida.
1987.

       Abstract.   Rates of recharge to the Floridan aquifer system at four sites in Alachua County
were estimated and water samples were  analyzed to determine if the recharge water had any effects on
the water quality of the aquifer. A total of about 33 million gallons per day recharges the upper part of
the aquifer system at Haile Sink, Alachua Sink, and drainage wells near Lake Alice . At the Kanapaha
Wastewater Treatment Plant, injection wells recharge an average of 6.1 million gallons per day into the
lower zone of the system.

       The samples of water entering the aquifer system collected at the four sites generally conformed
to the drinking water standards recommended by the U.S. Environmental Protection Agency in 1983.
Bacteria and nutrient concentrations were more variable in the recharge water than were other
constituents.  Organic compounds such as diazinon, lindane, and malathion were occasionally detected
in all recharge water, but concentrations never exceeded recommended limits.

       Bacteria were detected in  most wells sampled near the Gainesville recharge sites.  The highest
counts were from wells near Alachua Sink. At only one site was there a significant difference between
the quality of the recharge water and water from the wells sampled, although the recharge water tended
to be lower in calcium and iron than water from the Floridan aquifer system.  A sample from a well about
150 feet downgradient of a drainage well  near Lake Alice consisted of turbid water with a total
phosphorus  concentration of 75 milligrams per liter and a total nitrogen concentration of 57 milligrams
per liter.  Water flowing into the drainage well from the lake had a total nitrogen concentration of 1.6
milligrams per liter. Apparently, nutrient-rich suspended sediment in inflow to the drainage well settles
out of the water  and accumulates in the cavities in the limestone.

       Estimated loads entering the aquifer include 3,500 kilograms day of chloride, less than 0.43
kilogram  per day lead, 310 kilograms per day of nitrogen, and 150 kilograms per day of phosphorus. The
effects of the loads were not detected in most monitor wells. Apparently, some of the constituents may
settle out, some may be absorbed by the aquifer materials, and the remainder diluted and dispersed by
the extremely large volume of water in the aquifer.


Pierce, R. C. and  M. P. Wong.  "Pesticides  In Agricultural Waters: The Role of Water Quality
Guidelines." Canadian Water Resources Journal. V. 13, n. 3. pp. 33-49.  1988.

       Abstract.   Water of good quality is of primary importance to modern agriculture in determining
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the productivity of crops and the health and marketability of livestock. The quality of water used in
agricultural operations can be affected by numerous factors, including pesticide usage. This paper
focuses on the relationship between the use of pesticides in Canadian agriculture and the hazards
associated with the quality of agricultural waters  used in irrigation and livestock watering.  The extent
and complexity of this problem is assessed initially by examining the overlap between pesticide use and
agricultural water use in Canada. The inherent properties of selected pesticides used in Canadian
agriculture are highlighted and related to their potential for release to agricultural water supplies. Field
and laboratory investigators as related to agricultural water uses are reviewed and a discussion of
pesticide water quality guidelines to ensure protection of agricultural water supplies is provided.


Pitt, W. A. J. Jr. Effects Of Septic Tank Effluent On Ground- Water Quality, Dade County, Florida:
An Interim Report. Geological Survey Open File Report 74010. U.S. Geological Survey,
Tallahassee, Florida.  1974.

        Abstract.   At each of five sites in Dade County, where individual (residence) septic tanks have
been in operation for at least 15 years and where septic tank concentration is less than 5 per acre, a
drainfield site was selected for investigation to determine the effects of septic tank effluent on the quality
of the water in the Biscayne Aquifer.

        At each site two sets of multiple depth wells were drilled. The upgradient wells adjacent to the
drainfields in most places, were constructed in such a way that the aquifer could be sampled at 10, 20,
30, 40, and 60 feet below land surface.  The down-gradient wells at each site area 35 feet or more from
the up-gradient wells in the direction of ground-water flow, and allow the aquifer to be sampled at various
depths.

        Except at one site, no fecal coliforms were found below the 10-foot depth.  Total coliforms
exceeded a count of one colony per ml at the  60-fool depth at two sites.  At one site a fecal streptococci
count of 53 colonies per ml was found at the 60-foot depth and at another a count of seven colonies was
found at the 40-foot depth. The three types of bacteria occur in higher concentration in the northern
areas of the county than in the south.  Bacteria concentrations were also higher where the septic tanks
were more concentrated.
Pitt, W. A. J. Jr., H. C. Mattraw and H. Klein. Ground-Water Quality In Selected Areas Serviced By
Septic Tanks, Dade County, Florida. Geological Survey Open File Report 75-607.  U.S. Geological
Survey, Tallahassee, Florida. 1975.

       Abstract.   During 1971-74, the U.S. Geological Survey investigated the chemical, physical,
bacteriological, and virological characteristics of the ground water in five selected areas serviced by
septic tanks in Dade county, Florida. Periodic water samples were collected from multiple-depth groups
of monitor wells ranging in depth from 10 to 60 ft at each of the five areas. Analyses of ground water
from base-line water-quality wells in inland areas remote from urban development indicated that the
ground water is naturally high in organic nitrogen, ammonia, organic carbon and chemical oxygen
demand. Some enrichment of ground water with sodium provided a possible key to differentiating
septic-tank  effluent from other urban ground- water contaminant sources. High ammonia nitrogen,
phosphorus, and the repetitive detection of fecal coliform bacteria were characteristic of two 10-foot
monitor wells that consistently indicated the presence of septic-tank effluent in ground water.  Dispersion,
dilution, and various chemical processes have presumably prevented accumulation of septic-tank
effluent at depths greater than 20 ft, as indicated by the 65 types of water analyses  used in the
investigation. Fecal coliform bacteria were present on one or two occasions in many monitor wells but
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the highest concentration, 1,600 colonies/100 ml, was related to storm-water infiltration rather than
septic-tank discharge.

       Areal variations in the composition and the hydraulic conductivity of the sand and limestone
aquifer had the most noticeable influence on the overall ground-water quality. The ground water in the
more permeable limestone in south Dade County near Homestead contained low concentrations of
septic-tank related constituents, but higher concentrations of dissolved sulfate and nitrate. The ground
water in north Dade County, where the aquifer is less permeable, contained the highest dissolved iron,
manganese, COD, and organic carbon.


Power, J. F. and J. S. Schepers. "Nitrate Contamination Of Groundwater In North America."
Agriculture, Ecosystems and Environment. V. 26, n. 3-4. pp. 165-187. 1989.

       Abstract.   Groundwater serves as the primary domestic water supply for over 90% of the rural
population and 50% of the total population of North America. Consequently, protection of groundwater
from contamination is of major concern.  This paper reviews the problem of controlling nitrate pollution of
groundwater in North America. Nitrates in groundwater originate from a number of non-point sources,
including geological origins,  septic tanks,  improper use of animal manures, cultivation (especially
fallowing) precipitation , and fertilizers. Accumulation of nitrate N in groundwater is probably attributed to
different regions. Major areas of nitrate pollution often occur under irrigation because leaching is
required to control salt accumulation in the root zone. In the last few decades, areas under irrigation and
the use of N fertilizers have increased greatly,  and both of these have probably contributed to
groundwater nitrate problems. Use of known best management  practices (irrigation scheduling;
fertilization based on calibrated soil tests; conservation tillage; acceptable cropping practices;
recommended manuring rates) has been demonstrates to be highly effective in controlling leaching of
nitrates.  Government policies are needed that will encourage and reward the use of the best
management practices that help control nitrate accumulations in  groundwater.


Pruitt, J. B., D. E. Troutman and G. A.  Irwin.  Reconnaissance Of Selected Organic Contaminants
In Effluent And Ground Water At Fifteen Municipal Wastewater Treatment Plants In Florida.
Geological Survey Water-Resources Investigations Report 85-4167. U.S. Geological Survey,
Tallahassee, Florida. 1985.

       Abstract.   Results of a 1983-84 reconnaissance of 15  municipal wastewater treatment  plants
in Florida indicated that effluent form  most of the plants contains trace concentrations of volatile organic
compounds. Chloroform was detected in the effluent at 11  of the 15 plants and its common occurrence
was likely the result of chlorination. The maximum concentration of chloroform detected  in the effluent
sampled was  120 micrograms per liter. Detectable concentrations of selected organophosphorus
insecticides were also common. For  example, diazinon was detected in the effluent at 12 of the 15
plants with a maximum concentration of 1.5 micrograms per liter. Organochlorine insecticides, primarily
lindane, were detected in the effluent at 8 of the 15 plants with a maximum concentration of 1.0
micrograms per liter.

       Volatile compounds, primarily chloroform, were detected in water from monitor wells at four
plants and organophosphorus insecticides, primarily diazinon, were present in the ground water at three
treatment plants. Organochlorine insecticides were not detected in any samples from monitor wells.
Based on the  limited data available, this cursory reconnaissance suggests that the organic contaminants
commonly occurring in the effluent of many of the treatment plants are not transported into the local
ground water.

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Ragone, S. E. Geochemical Effects Of Recharging The Magothy Aquifer, Bay Park, New York,
With Tertiary-Treated Sewage. Geological Survey Professional Paper 751-D.  U.S. Government
Printing Office, Washington, D.C.  1977.

       Abstract.   A ground-water deficit of 93.5 to 123 million gallons per day (4.10 to 5.39 cubic
meters per second) has been predicted for Nassau County, N.Y., by the year 2000 in a State report.
Because of the predicted deficit, the U.S. Geological Survey, in cooperation with the Nassau County
Department of Public Works, began an experimental deep-well recharge program in 1968. Thirteen
recharge tests using tertiary-treated sewage (reclaimed water) and six tests using water from the
domestic supply (city Water) were completed between 1968 and 1973. Recharge was through an 18-
inch (46-centimeter) diameter recharge well screened in the Magothy aquifer between depths of 418  and
480 feet (127 and 146 meters) below land surface. Recharge rates ranged from about 200 to 400
gallons per minute (13 to 25 liters per second). In the longest test, reclaimed water was injected during
84.5 days of a 199-day period.

       Although the iron concentration of native water in the recharge zone and reclaimed water is less
than 0.5 milligrams per liter, the iron concentration of samples collected from  observation wells 20, 100,
and 200 feet (6.1, 30, and 61 meters) from the recharge well, and screened in the zone of recharge,
approached 3 milligrams per liter at times. Iron mass-balance calculations indicate that dissolution of
pyrite and marcasite (FeS2) in the aquifer are the only known sources of iron that could explain the
observed increase. Within a 20-foot (6.1-meter) radius of the recharge well, dissolved oxygen in the
reclaimed water oxidizes pyrite and release Fe+^ (ferrous iron) to solution.  However, the amount of  iron
in water continues to increase with distance from the recharge well even though dissolved oxygen is  no
longer present in water reaching the 20-foot (6.1 meter)  radius; the mechanism by which iron continues
to be dissolved in not quantitatively understood.

       Some cation exchange also occurs during recharge. Loss of ammonium and potassium cations
in the water was balanced by an increase in H+, which at times caused pH to decrease by more than 1
pH  unit.

       Tertiary treatment removes 90 to 98 percent of the  phosphate, MBAS (methylene blue active
substances), and COD (chemical oxygen demand), leaving an average of 0.17, 0.07, and 9 milligrams
per liter, respectively. During recharge, phosphate concentrations remain at native-water levels at the
20-, 100-,  and 200-foot (6.1-, 30-, and 61-meter) observation wells, which indicates phosphate retention
by the aquifer. Some MBAS and COD are retained at the 100-and 200- foot (30-and 61-meter) wells,
presumably by adsorption reactions.


Ragone, S. E., H. F. H.  Ku and J. Vecchioli.  "Mobilization Of Iron In Water In The Magothy Aquifer
During Long-Term Recharge With Tertiary-Treated Sewage, Bay Park, New York." Journal
Research U.S. Geological Survey.  V. 3, n. 1. pp. 93-98. 1975.

       Abstract.   Tertiary-treated sewage (reclaimed water) has been recharged by well into the
Magothy aquifer qt Bay Park, N.Y-, intermittently since 1968. The longest of 13 recharge tests, the
subject of this report, lasted 84.5 days. This was sufficient time for the reclaimed water to reach an
observation well 200 ft (61 m) from the recharge well. Although the iron concentrations of the reclaimed
water and the native water were less than 0.4 mg/l, the iron concentrations of samples from observation
wells 20,000, and 200 ft (6,30, and 61 m) from the recharge well at times approached 3 mg/l. Source of
the  iron is pyrite that is native to the aquifer.
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 Ragone, S. E. and J. Vecchioli. "Chemical Interaction During Deep Well Recharge Bay Park, New
 York."  Ground Water. V. 13,  n. 1. Reprint.  1975.

        Abstract.  The U.S. Geological Survey, in cooperation with the Nassau County Department of
 Public Works, recharged tertiary-treated sewage (reclaimed water) into the Magothy aquifer in 13
 recharge experiments between 1968 and  1973. The recharge resulted in a degradation in water quality
 with respect to iron concentration and pH. Iron concentration increased from the range 0.14 to 0.30
 milligrams per litre to as much as 3 milligrams per litre at the 20-. 100-, and 200-foot or 6.1-,  30-, and 61-
 metre observation wells as the reclaimed water displaced native water. The increase was presumably  a
 result of pyrite dissolution.  The pH of the  water decreased from the range 5.22 to 5.72 to a low of about
 4.50, predominantly as a result of cation-exchange reactions.


 Ramsey, R. H. Ill, J. Borreli and C. B. Fedler. "The Lubbock, Texas, Land Treatment System."
 Irrigation Systems For The 21st Century, Portland, Oregon,  1987. (American Society Of Civil
 Engineers, New York, New York, pp. 352-361).  1987.

        Abstract.   The land treatment system at Lubbock, Texas provides an  excellent model for
 studying the response of a system to growth.  It also provides insights and justification for current criteria
 used to  design slow-rate land treatment systems.  During the 62 years of operation, the Lubbock Land
 Treatment System responded to a substantial increase in the volume of the effluent and changes in
 environmental concern for  groundwater pollution.  While certain  problems persist, they have
 demonstrated that shortcomings in the system design can be turned into positive assets. Groundwater
 from beneath  the treatment farms is used to provide flat water recreation and for irrigation of city parks
 and cemeteries.
Razack, M., C. Drogue and M. Baitelem.  "Impact Of An Urban Area On The Hydrochemistry Of A
Shallow Groundwater (Alluvial Reservoir) Town Of Narbonne, France."  Hydrological Processes
And Water Management In Urban Areas, Duisburg, Federal Republic Of Germany, 1988.
(International Hydrological Programme, UNESCO, pp. 487-494).  1988.

       Abstract.   The Roman founded urban area of Narbonne in Southern France is built upon a
shallow groundwater.  This reservoir which thickness ranges from 10 to 30 meters is composed by the
packing of varied materials and by quaternary deposits.  A hydrochemical survey carried out during the
Summer 1984 and the Winter 1985, showed an important impact of the urban activity on the
groundwater quality.  This impact is expressed through the superimposition beneath the city of a
chemistry of exogeneous elements issued from urban activity (SO4,NC>3) and of a natural chemistry (Na,
Cl), both displaying different aerial patterns.


Rea, A. H. and J. D. Istok.  "Groundwater Vulnerability To Contamination: A Literature Review."
Irrigation Systems For The 21st Century, Portland, Oregon,  1987.  (American Society Of Civil
Engineers, New York, New York, pp. 362-367). 1987.

       Abstract.   Methods are needed to allow regulatory agencies and resource managers to predict,
from readily available data, the potential for groundwater contamination problems.  Regional maps
developed from these methods can aid in planning and allocation of resources. The literature was
searched for methods capable of filling this need. Six methods were selected and compared using
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hypothetical hydrogeologic settings. Based on the results obtained, which varied considerably between
methods, none of the methods is completely satisfactory. Of the reviewed methods, "DRASTIC" seemed
to be most suitable.
Reichenbaugh, R. C. Effects On Ground-Water Quality From Irrigating Pasture With Sewage
Effluent Near Lakeland, Florida.  Geological Survey Water-Resources Investigations 76-108.  U.S.
Geological Survey, Tallahassee, Florida. 1977.

       Abstract.   Since 1969, on the average, 25,000 gallons (94,600 liters per day) of domestic
secondary-treated effluent has been used each day to supplement irrigation  of 30 acres (12 hectares) of
grazed pasture north of Lakeland, in west-central Florida. The U.S. Geological Survey began a study of
the site several months after sprinkler application of the effluent to the Myakka sands (well- sorted, fine,
acid) was started.  The site, on the south shore of Lake Gibson, is underlain  by as much as 60 feet (18
meters) of sand, sandy clay, and clay, containing the water-table aquifer, and two relatively unimportant
confined aquifers, which in turn are underlain by the confined Floridan aquifer.

       Monitor-wells were constructed to various depths in clusters near the effluent- irrigated pasture.
The water table in the surficial aquifer varied from 1 to 3.3 feet (0.3 to 1.0  meters) below the land
surface. Ground-water quality was evaluated by analysis of water samples collected three times over a
1-year period.

       Ground-water beneath the irrigated pasture showed slight increases  in cations and anions which
are attributed to irrigation with the effluent. The concentration of total nitrogen (predominantly ammonia
and organic nitrogen) was reduced to less than 20 percent of that in the upper 8 feet (2.4 meters) of
pasture soils, and there was no increase in concentration below 20 feet (6.1  meters), or in downgradient
ground water. There was no evidence of phosphorus or carbon contamination of ground water at the
site.  Though small numbers of bacteria were noted in some samples from nine wells, most were of the
coliform group.  Only four wells yielded samples containing bacteria of probable fecal origin—one colony
per 100 milliliters in each sample.

       There was no detected accumulation of solids at the soil surface.  Organic carbon, pH, and
kjeldahl nitrogen concentrations of the soil in the irrigated pasture were only  slightly higher when
compared to soil outside the pasture.  As of 1972, the low-rate application of the effluent to the pasture
apparently has had little effect on the soil and ground water.


Reichenbaugh, R. C., D. P. Brown and C. L. Goetz.  Results Of Testing  Landspreading  Of Treated
Municipal Wastewater At St. Petersburg, Florida. Geological Survey Water-Resources
Investigations Report 78-110. U.S. Geological Survey, Tallahassee, Florida. 1979.

       Abstract.    Chlorinated secondary-treated effluent was used to irrigate a grassed 4-acre site at
rates of 2 and 4 inches per week for periods of 11 and 14 weeks, respectively. Part of the site was
drained by tile lines 5 feet below land surface. Chemical and bacteriological changes in the acidic
ground water in the shallow and aquifer and in the effluent from the drains were studied.

       Irrigation of the drained plot resulted in rapid passage of the applied  wastewater through the soil
and,  consequently, poor nitrogen removal.  The rapid percolation permitted  nitrification but prevented
denitrification. Thus, the effluent from the drains contained as much as 5.2  milligrams per liter nitrate-
nitrogen. Irrigation of the undrained plot resulted in more extensive nitrogen removal.
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        Total phosphorus in the shallow ground water at the site increased from a maximum of 1.4
milligrams per liter before irrigation to as much as 5 milligrams per liter in the ground water 5 feet below
land surface.

        Concentrations of nitrogen and phosphorus did not increase in ground water downgradient from
the site, although increased chloride concentrations demonstrated downgradient migration of the applied
wastewater.

        Prior to irrigation, total coliform bacteria were not detected in ground water at the site.  After
irrigation, total and fecal coliforms were detected in the ground water at the site and downgradient. The
nitrifying bacteria Nitrosomonas and Nitrobacter at the irrigated site were most abundant at the soil
surface; their numbers decreased with depth.


Rein, D. A., G. M. Jamesson and R. A. Monteith. "Toxicity Effects Of Alternative Disinfection
Processes." Water Environment Federation 65th Annual Conference & Exposition, New Orleans,
Louisiana, 1992. (Water Environment Federation, Alexandria, Virginia, pp. 461-470).  1992.

        Abstract.   Chlorination/dechlorination, ultraviolet irradiation, and ozonation were evaluated in
side-by-side pilot/bench scale tests at the Akron, Ohio Water Pollution Control Station. The objective of
the evaluation was to investigate the effect of these disinfection Processes on final effluent toxicity.

        Six sets of chronic and two sets of acute whole effluent toxicity tests were conducted using P.
promelas and C. dubia. After the first two sets of tests, it became apparent that differences between the
processes could only be seen in 100 percent effluent samples. The test protocol was then modified to
compare the relative toxic response in terms of survival and reproduction of C. dubia in 100 percent
effluent samples.

       Although very little statistically estimated toxicity was found in any of the process effluents, the
chlorination/ dechlorination process effluent consistently produced a greater relative toxic response than
either ultraviolet irradiation or ozonation. The chlorination/ dechlorination process produced the greatest
relative toxic response for offspring produced and/or survival of C. dubia in seven of eight tests sets
using 100 percent effluent samples.


Rice, R. C., D. B. Jaynes and R. S. Bowman.  "Preferential Flow Of Solutes And Herbicide Under
Irrigated Fields."  Transactions Of The American Society Of Agricultural Engineers.  V. 34, n. 2.
pp. 914-918.  1991.

       Abstract.   Over the past several years, there has been an increasing concern of groundwater
contamination from agricultural chemicals. Until recently it was generally believed that pesticides would
not move to the groundwater. Starting in the mid-seventies more cases of pesticide contamination were
reported. This article discusses recent experiments where accelerated leaching of solutes and a
herbicide were observed under intermittent flood and sprinkler irrigation.  Preferential flow phenomena
resulted in solute and herbicide velocities of 1.6 to 2.5 times faster than calculated by traditional water
balance methods and piston flow model. Little preferential flow was observed under continuously
flooded conditions on a loam soil. Generally, preferential flow is thought to occur in coarse grained soils
, cracked soils or in macro-pores such as root or worm holes. The bypass that we observed was in sandy
loam and sandy soils with little or no structure.  Understanding the preferential flow phenomena is
necessary when predictive flow models are used.
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Ritter, W. F., F. J. Humenik and R. W. Skaggs.  "Irrigated Agriculture And Water Quality In East."
Journal of Irrigation and Drainage Engineering. V. 115, n. 5.  pp. 807-821. 1989.

       Abstract.   The northeastern and Appalachian states have a diverse array of geology, soils,
and climate.  Irrigation is concentrated in a few states, with the largest irrigation area in the Coastal Plain
soils.  Most of these soils are sandy and very susceptible to leaching. The groundwater recharge area in
the Coastal Plain is directly above the aquifer.  Most of the increase in irrigation has been to irrigate corn
in Delaware, Maryland, and Virginia. Groundwater studies have been conducted in Delaware, Maryland,
and New York in irrigated regions.  Nitrate and aldicarb leaching has occurred on Long Island, New York,
where potatoes are grown. Poultry  manure is the largest source of nitrate contamination of the water
table aquifer on the Delmarva Peninsula in Maryland.  Both pesticide and nitrate leaching under irrigation
have been studied in Delaware.  A total water management system that can be used for both drainage
and subsurface irrigation has been developed in North Carolina. The system will increase crop yields
and has the potential for reducing nitrates by water table control.


Ritter, W. F., R. W. Scarborough  and E. M. Chirnside.  "Nitrate Leaching Under Irrigation On
Coastal Plain Soil."  Journal of Irrigation  and Drainage Engineering. V. 117, n. 4. pp. 490-502.
1991.

       Abstract.  The effect of irrigation and nitrogen management on ground-water quality was
evaluated for four years on a Sassafras sandy loam Coastal Plain soil.  Applying the greatest portion of
the nitrogen by side-dressing and by fertigation were compared. Maintaining optimum soil moisture and
partial irrigation (applying one half the water as optimum irrigation) were the water management
practices investigated. Nitrate concentrations increased in the ground  water for all nitrogen and
irrigation-management practices. The mass  of the nitrate leached was related to the drainage volume. In
all but one year the largest mass of nitrate was leached during the fall and winter months, when the
largest amount of recharge occurs. Very little nitrate was leached during the growing season for any
nitrogen or irrigation management practice except for one year when 30 cm of rainfall occurred in
August.  The mass of nitrate leached during  that growing season ranged from 33.9 kg/ha for partial
irrigation to 139.0 kg/ha for full irrigation.


Robinson, J. H. and  H. S. Snyder. "Golf Course Development Concerns In Coastal Zone
Management." Coastal Zone '91: Proceedings Of The Seventh Symposium On Coastal And
Ocean Management, Long Beach, California, 1991. (American Society Of Civil Engineers, New
York, New York, pp.  431-442). 1991.

       Abstract.  The rapid growth of golf course development in South Carolina's coastal zone
presents new challenges in protecting coastal water and wetlands. While filling or dredging of wetland
resources for golf courses development is a  practice of the past, golf course designers make every effort
to minimize their proximity to wetland resource areas.  Coastal zone management concerns  associated
with golf course development include the protection of adjacent wetland resources from (1) nutrient and
chemical laden storm water runoff, (2)  aerosol from "fertigation," a mixture  of fertilizer and irrigation
water, and treated effluent irrigation systems, and  (3)  physical impacts associated with wetland
crossings, play-through areas, and player intrusion. This paper first provides a brief overview of current
literature associated with the use of chemicals on golf courses and their impacts on  man and the coastal
environment.  This paper then focuses on best management practices which can be utilized in the
physical design and management of golf courses to minimize impacts on coastal resources, drawing
upon examples from golf courses recently constructed or currently under development in coastal South
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 Carolina.


 Rosenshein, J. S. and J. J. Mickey.  "Storage Of Treated Sewage Effluent And Storm Water In A
 Saline Aquifer Pinellas Peninsula, Florida."  Ground Water.  V. 15, n. 4.  pp. 284-293.  1977.

        Abstract.   The Pinellas Peninsula, an area of 750 square kilometres (290 square miles) in
 coastal west-central Florida, is a small hydrogeologic replica of Florida. Most of the Peninsula's water
 supply is imported from wells fields as much as 65 kilometres (40 miles) inland.  Stresses on the
 hydrologic environment of the Peninsula and on adjacent water bodies, resulting from intensive water-
 resources development and waste discharge, have resulted in marked interest in subsurface storage of
 waste water (treated effluent and untreated storm water) and in future retrieval of stored water for
 nonpotable use.  If subsurface storage is approved by regulatory agencies, as much as 265 megalftres
 per day (70 million  gallons a day) of waste water could be stored underground within a few years, and
 more than 565 megalitres per day (150 million gallons a day)  could be stored in about 25 years. This
 storage would constitute a large resource of nearly fresh water in the saline aquifers underlying about
 250 square kilometres (200 square miles) of the Peninsula.

        The upper  1,060 metres (3,480 feet) of the rock column underlying four test sites on the Pinellas
 Peninsula have been explored. The rocks consist chiefly of limestone and dolomite. Three moderately
 to highly transmissive zones, separated by  leaky confining beds, (low permeability limestone) from about
 225 to 380 metres  (740 to 1,250 feet) below mean sea level, have been identified in the lower part of the
 Floridan aquifer in the Avon Park Limestone. Results of withdrawal and injection tests in Pinellas County
 indicate that the middle transmissive zone has the highest estimated transmissivity -- about 10 times
 other reported values.  The chloride concentration of water in this zone, as well as  in the Avon Park
 Limestone in Pinellas Peninsula, is about 19,000 milligrams per litre.  If subsurface storage is approved
 and implemented, this middle zone probably would be used for storage of the waste water and the one
 would become the  most extensively used in Florida for this purpose.


 Sabatinl, D. A. and T. A. Austin. "Adsorption, Desorption And Transport Of Pesticides  In
 Groundwater: A Critical Review." Planning Now For Irrigation And Drainage In The 21st Century,
 Lincoln, Nebraska, 1988. (American Society Of Civil Engineers, New York,  New York, pp. 571-
 579). 1988.

        Abstract.   Adsorption and desorption are major mechanisms affecting the transport and fate of
 pesticides in groundwater. Equilibrium, chemical nonequilibrium and physical nonequilibrium  adsorption
 relationships for predicting pesticide transport are  reviewed.  Hysteresis of desorption and relationships
 for predicting linear equilibrium coefficients  are discussed.


 Sabol, G.  V., H. Bouwer and P. J. Wierenga.  "Irrigation Effects In Arizona And New Mexico."
 Journal of Irrigation and Drainage Engineering. V. 113, n. 1.  pp. 30-57.  1987.

        Abstract.   Irrigated agriculture accounts for about 90% of all water consumption in both
Arizona and New Mexico.  More than 50% of this water is pumped from groundwater sources. Some
 portion of the applied irrigation  water is returned to the groundwater supply through deep percolation.
Several field studies have been conducted in these states to measure the quantity  and quality of water
that is recharging the aquifer.  These studies indicate  that groundwater quality in Arizona and New
Mexico has been deleteriously  affected in deep supplies. The magnitude and time rate of groundwater
quality changes is a function of irrigation  management practice, fertilizer and  pesticide applications,
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quality of irrigation water, rate of groundwater level decline, presence of perched zones that intercept
percolating water, proximity to surface water supplies, leakage through and along well casings, and soil
salinity.


Salo, J. E., D. Harrison and E. M. Archibald. "Removing Contaminants By Groundwater Recharge
Basins."  Journal Of The American Water Works Association. V. 78, n. 9.  pp. 76-81. 1986.

       Abstract.   The effects of urban runoff used to recharge groundwater basins in the Fresno,
Calif., area are discussed. The study, which was part of the US Environmental  Protection Agency's
nationwide urban runoff program, was undertaken to determine the environmental effects on
groundwater quality  and to identify management practices that would mitigate adverse effects.  No
deterioration of groundwater quality because of recharge with runoff was found, although the authors
recommend a more  thorough investigation of effects of recharge with runoff from industrial sites.


Schiffer, D. M. Effects Of Three Highway-Runoff Detention Methods On Water Quality Of the
Surficlal Aquifer System In Central Florida.  Geological Survey Water-Resources Investigations
Report 88-4170.  U.S. Geological Survey, Tallahassee, Florida. 1989.

       Abstract.   Water quality of the surficial aquifer system was evaluated at one exfiltration pipe,
two ponds (detention and retention), and two swales in central Florida, representing three runoff
detention methods, to detect any effects from infiltrating highway runoff. Concentrations of major ions,
metals, and nutrients were measured in  ground water and  bottom sediments form 1984 through 1986.

       At each study area, concentrations in ground water near the structure were compared to
concentrations in ground water from an upgradient control site. Ground-water quality data also were
pooled by detention  method and statistically compared to detect any significant  differences between
methods.

       Analysis of variance of the rank-converted water-quality data at the exfiltration pipe indicated
that mean concentration s of 14 to 26 water-quality variables are significantly different among sampling
locations (the pipe, unsaturated zone, saturated zone, and the control well).  Most of these differences
are between the unsaturated zone and other locations. Only phosphorus is significantly higher in ground
water near the pipe than in ground water at the control well.

       Analysis of variance of rank- converted water-quality data at the retention pond indicated
significantly differences in 14 to 25 water-quality variables among  sampling locations (surficial aquifer
system, intermediate aquifer, pond,  and  the control well), but mean concentrations in ground water below
the pond were never significantly higher than in ground water from the control well. Analysis of variance
results at other study areas indicated few significant differences in water quality among sampling
locations.

       Values of water-quality variables measured in ground water at all study  areas generally were
within drinking water standards,  the few exceptions included pH (frequently lower than the limit of 6.5 at
one pond and both swales), and  iron, which frequently exceeded 300 micrograms per liter in ground
water at one swale and the detention pond.

       Large concentrations of polyaromatic hydrocarbons were measured in sediments at the retention
pond, but qualitative analysis of organic  compounds in ground water from three wells indicated
concentrations of only 1 to 5 micrograms per liter at on site, and below detection level (1 microgram per
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 liter) at the other two sites. This may be an indication of immobilization of organic compounds in
 sediments.

        Significant differences for most variables were indicated among ground-water quality data
 pooled by detention method.  Nitrate nitrogen and phosphorus concentrations were highest in ground
 water near swales and exfiltration pipe, the Kjeldahl nitrogen was highest near ponds. Chromium,
 copper, and lead concentrations in ground water were frequently below detection levels at all study
 areas, and no significant differences among detention methods were detected for any metal
 concentration with the exception of iron. High iron concentrations in ground water near the detention
 pond and one swale most likely were naturally occurring and unrelated to highway runoff.

        Results of the study indicate that natural processes occurring in soils attenuate inorganic
 constituents in runoff prior to reaching the receiving  ground water.  However, organic compounds
 detected in sediments at the retention pond indicate a potential problem that may eventually affect the
 quality of the receiving ground water.


 Schmidt, K. D. and I. Sherman. "Effect Of Irrigation On Groundwater Quality In California."
 Journal Of Irrigation And Drainage Engineering. V. 113, n. 1. pp. 16-29. 1987.

        Abstract.   Deep percolation of irrigation return flow is a major source of recharge beneath
 most irrigated areas in California. Tile drainage, soils, water in the vadose zone,  and shallow
 groundwater have been studied. Nitrate, salinity, and several  pesticide have received the most attention.
 Numerous parts of the San Joaquin Valley have been investigated, as well as parts of the Sacramento
 Valley, Imperial Valley, Los Angeles Basin, and several other valleys.  The results of the studies indicate
 that irrigation return flow usually exerts a substantial impact on groundwater quality.  High nitrate
 contents in groundwater beneath irrigated areas are often a result of irrigation. In addition, extensive
 pollution of shallow groundwater in parts of the San  Joaquin Valley have been caused by use of the
 pesticide DBCP.


 Schneider, B. J., H. F.  H. Ku and E. T. Oaksford.  Hydrologic Effects Of Artificial-Recharge
 Experiments With Reclaimed Water At East Meadow, Long Island, New York. Geological Survey
 Water Resources Investigations Report 85-4323. U.S. Geological Survey, Denver, Colorado.
 1987.

       Abstract.   Artificial-recharge experiments  were conducted at East meadow from October 1982
 through January 1984 to evaluate the degree of ground-water mounding and the  chemical effects of
 artificially replenishing the ground-water system with tertiary-treated wastewater.  More than 800 million
 gallons of treated effluent was returned to the upper glacial aquifer through recharge basins and injection
 wells in the 15-month period.

       Reclaimed water was provided by the Cedar Creek advanced wastewater-treatment facility in
 Wantagh, 6 miles away. The chlorinated effluent was pumped to the recharge facility, where it was fed
 to basins by gravity flow and to injection wells by pumps. An observation- well network was  installed at
the recharge facility to monitor both physical and chemical effects of reclaimed water on the ground-
water system.

       Observations during the recharge tests indicate that the two most significant factors in limiting
the rate of infiltration through the basins floor were the recharge- test duration and quality of reclaimed
water.  Head buildup in the aquifer beneath the basins ranged from 4.3 to 6.7 feet, depending on the
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quantity and duration of water application. Head buildup near the injection wells within the aquifer
ranged from 0.3 to 1.2 feet. The head buildup in the injection wells is attributed to biological, physical,
and chemical actions, which can operate separately or together.  Recharge basins provided a more
effective means of moving large quantities of reclaimed water into the aquifer than injection wells.

       Two basins equipped with central observation manholes permit the acquisition of data on the
physical and chemical processes that occur within the unsaturated zone during recharge. Results of 3-
day and 176-day ponding tests in basins 3 and 2, respectively, indicate that reclaimed water is relatively
unchanged chemically by percolation through the unsaturated zone because (1) the sand and gravel of
the upper glacial aquifer is unreactive, (2) the water moves to the water table rapidly, and (3) the water is
highly treated before recharge.

       The quality of water in the aquifer zones affected by recharge improved, on  the whole. Ground-
water concentrations of nitrate nitrogen and several low-molecular- weight hydrocarbons, although
significantly above drinking-water standards before recharge, decrease to well within drinking-water
standards as a direct result of recharge. Sodium and chloride concentrations increased above
background levels as a result of recharge but remained well within drinking-water standards and the New
York State effluent standards established for this ground-water-recharge study.


Seaburn, G. E. and D. A. Aronson.  Influence Of Recharge Basins On The Hydrology Of Nassau
And Suffolk Counties, Long Island, New York. Geological Survey Water Supply Paper 2031.  U.S.
Government Printing Office, Washington, D.C. 1974.

       Abstract.   An investigation of recharge basins on Long Island was made by the U.S.
Geological Survey in  cooperation with the New York State Department of Environmental Conservation,
Nassau County Department of Public Works, Suffolk County Water Authority. The major objectives of
the study were to (1) catalog  basic physical data on the recharge basins in use on Long Island, (2)
measure quality and quantity of precipitation and inflow, (3) measure infiltration rates at selected
recharge basins, and (4) evaluate regional effects of recharge basins on the hydrologic system of Long
Island. The area of study consists of Nassau and Suffolk Counties-about 1,370 square miles -in eastern
Long Island, N.Y.

       Recharge basins, numbering more than 2,100 on Long Island in 1969, are open pits on
moderately to highly permeable sand and gravel deposits. These pits are used to dispose of storm
runoff from residential, industrial, and commercial areas, and from highways, by  infiltration of the water
through the bottom and sides of the basins.

       The hydrology of three recharge basins on Long Island - Westbury, Syosset, and Deer Park
basins- was studied.  The precipitation-inflow relation showed that the average percentage of
precipitation flowing into each basin were roughly equivalent to the average percentage of impervious
areas in the total drainage areas of the basins. Average percentages of precipitation flowing into the
basins as direct runoff were 12 percent at the Westbury basin, 10 percent at the Syosset basin, and 7
percent at the Deer Park basin. Numerous open-bottomed storm-water catch basins at Syosset and
Deer Park reduced the proportion of inflow to those basins, as compared with the Westbury basin, which
has only a few open-bottomed catch basins.

       Inflow hydrographs for each basin typify the usual urban runoff hydrograph-  steeply rising and
falling limbs, sharp peaks, and short time bases.  Unit hydrographs for the Westbury and the Syosset
basins are not  expected to change; however, the unit hydrograph for the Deer Park basin is expected to
broaden somewhat as a result of additional future house construction within the drainage area.
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        Infiltration rates averaged 0.9 fph (feet per hour) for 63 storms between July 1967 and May 1970
at the Westbury recharge basin, 0.8 fph for 22 storms from July 1969 to September 1970 at the Syosset
recharge basin, and 0.2 fph for 24 storms from March to September 1970 at the Deer Park recharge
basin.  Low infiltration rates at Deer Park resulted mainly from (1) a high percentage of eroded silt, clay,
and organic debris washed in from construction sites in the drainage area, which partly filled the
interstices of the natural deposits, and (2) a lack of well-developed plant-root system on the younger
basin, which would have kept the soil zone more permeable.

        The apparent rate of movement of storm water through the unsaturated zone below the
unsaturated zone below each basin averaged 5.5 fph at Westbury, 3.7 fph at Syosset,  and 3.1 fph at
Deer Park. The rates of movement for storms during the warm months (April through October) were
slightly higher than average, probably because the recharging water was warmer than it was during the
rest of the year, and therefore, was slightly less viscous.

        On the average, a 1 -inch rainfall resulted in a peak rise of the water table directly below each
basin of 0.5 fool; a 2-inch rainfall resulted in a peak rise of about 2 feet. The mound commonly
dissipated within 1 to 4 days at Westbury, 7 days to more than 15 days at Syosset, and 1 to 3 days at
Deer Park, depending on the magnitude of the peak buildup.

        Average annual ground-water recharge was estimated to be 6.4 acre-feet at the Westbury
recharge basin, 10.3 acre-feet at the Syosset recharge basin, and 29.6 acre-feet at the Deer Park
recharge basin.

        Chemical composition of precipitation at Westbury, Syosset, and Deer Park drainage areas was
similar:  hardness of water ranged from 6 to 56 mg/l (milligrams per liter as calcium and magnesium
hardness), dissolved-solids content ranged from 21 to 124 mg/l, and pH ranged from 5.9 to 6.6. Calcium
was the predominant cation, and sulfate and bicarbonate were the  predominant anions. Atmospheric dust
and gaseous sulfur compounds associated with the Northeast urban environment mainly account for this
combination of ions in precipitation.

        Chemical composition of the inflow to the basins was also similar in each of the three basins.  In
general, hardness of the water samples collected at Westbury, Syosset, and Deer Park recharge basins
in 1970  was less than 50 mg/l (as calcium and magnesium hardness), and dissolved-solids content was
less than 100 mg/l. The pH ranged from 6.1 to 7.4.  The concentrations of most constituents in inflow
were greater than those in precipitation; precipitation contributed 70 to 88 percent of the loads of
dissolved constituents in the inflow.

        Only three of 11 pesticides sought by chemical analysis were detected.  A maximum  DDT
concentration of 0.08 ug/l (micrograms per liter) was determined for an inflow sample to Westbury
recharge basin. Concentrations of other pesticides were 0.02 ug/ I or less.

        Total concentration of  pesticides detected in the soil layers on the floors of each basin generally
ranged from 0.4 to 40 mg/l. The greater organic content of the soil layers, compared with that of the
underlying natural deposits, suggests that pesticides as well as other organic material are effectively
reduced or removed from the  infiltrating water in the soil layer.

        Ground-water recharge from precipitation through the total area (73,000 acres) drained by 2,124
recharge basins in operation in 1969 was estimated to be 166,000 acre-feet per year, or about 148
million gallons per day. Ground-water recharge in the areas where recharge basins are used is probably
equivalent to or may slightly exceed recharge under natural conditions.

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Shirmohammadi, A. and W. G. Knisel.  "Irrigated Agriculture And Water Quality In South."
Journal of Irrigation and Drainage Engineering.  V. 115, n. 5. pp. 791-806.  1989.

        Abstract.   Irrigated agriculture in the humid region has resulted in more intensive management
including crop production and associated  increase in fertilizer and pesticide use. Multiple cropping in
most of the southeast (Alabama, Florida, Georgia, and South Carolina)and Delta (Arkansas, Louisiana,
and Mississippi) states increases the demand for water and agricultural chemicals.  Pesticide usage in
the 48 states and the District of Columbia totaled 299,892,159 kg of active ingredient (Al) by 1982.
Agricultural chemicals may percolate to aquifers in some soils and geologic formations resulting in
groundwater contamination. Groundwater fluctuations are related to irrigation. Groundwater quality data
are used to show the trend in quality related to irrigated agriculture and cropping systems. Areas with
specific groundwater problems such as salt-water intrusion and pesticide levels  are identified. A total of
17 pesticides have been reported in groundwater in the United States and four of these were found in the
southeast and Delta states.  Data show that less than 1% of wells sampled in the southeast and Delta
states had nitrate concentrations exceeding 10 mg/'L (drinking water standard).  Degradation of surface
water quality relative to  irrigation is discussed.


Smith, S. O. and D. H.  Myott.  "Effects Of Cesspool Discharge On Ground-Water Quality On Long
Island,  N.Y." Journal Of The American Water Works Association.  V. 67, n. 8.  pp. 456-458.  1975.

        Abstract.   Large amounts of household wastes, discharged through cesspools, have resulted
in deterioration of groundwater quality on  Long Island. Although nitrate pollution poses the greatest
threat to the Island's water supplies, other constituents derived from cesspool leachings are increasing.
Municipal sewering projects which have been undertaken as a solution  are discussed in the following.


Spalding, R. F. and L. A. Kitchen. "Nitrate In The Intermediate Vadose Zone Beneath Irrigated
Cropland."  Ground Water Monitoring Review. V. 8,  n. 2. pp. 89-95. 1988.

        Abstract.   More than 1000 feet of fine-textured, unsaturated zone core beneath nitrogen-
fertilized and irrigated farmland was collected, leached and analyzed for nitrate-nitrogen. Fertility plots
treated with 200, 300 and 400 Ibs N/acre/yr accumulated significant quantities of nitrate-nitrogen in those
vadose zone below the crop rooting zone. The average nitrate-nitrogen concentration approximately
doubled with each 100 Ibs. N/acre/ yr increment above the 100 Ibs. N/acre/yr treatment.  Nitrate loading
estimates for the plots treated with 400 Ibs./N/acre/yr indicate that over 1200 Ibs. N/acre was in the
vadose zone beneath the crop rooting zone.  In 15 years, the nitrate moved vertically at least 60 feet
through these fine-textured, unsaturated sediments.  As  much as 600 Ibs. N/acre have accumulated in
the vadose zone under independent corn producer's fields.

       Vadose zone sampling  is effective in predicting future non-point nitrate-contaminated areas.


Squires, R.  C., G. R. Groves and W. R. Johnston.  "Economics Of Selenium Removal From
Drainage Water." Journal of Irrigation  and Drainage Engineering.  V. 115,  n. 1.  pp. 48-57. 1989.

       Abstract.   A treatment system consisting of biological reactors and microfiltration has been
developed to remove soluble selenium species from agricultural drainage water. The process was
evaluated over a two-year period, and the reactor configurations and specific removal rates of nitrate and
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selenium were optimized. Trials on the operation of a pilot solar salt works to concentrate the detoxified
water after treatment to recover salts were also carried out. The treatment process reduced the selenium
concentration of the drainage water from over 500 ug/L to 10-50 ug/L as Se. Boron in the drainage water
was reduced from 6-8 mg/L to 0.5 mg/L by an ion exchange post-treatment. This resin also removed
residual selenium to below 10 ug/L. Trials on high-salinity drainage waters, similar to those found in
evaporation ponds, were successful and gave enhanced specific selenium removal rates. The costs of
removing selenium or selenium  and boron from the drainage water were estimated to be $0.038-
0.052/m* and $0.050-0.071/m3, respectively, after allowance for by-product recovery (boric acid and
sodium sulfate) credits.


Squires, R. C. and R. Johnston. "Selenium Removal -- Can We Afford It?"  Irrigation Systems For
The 21st Century, Portland, Oregon, 1987. (American Society Of Civil Engineers, New York, New
York, pp. 455-467). 1987.

       Abstract.   The process of biologically removing the element selenium from agricultural
drainage water is discussed and an economic evaluation of the process is presented.


Steenhuis, T., R. Paulsen, T. Richard, W. Staubitz, M. Andreini and J. Surface. "Pesticide And
Nitrate Movement Under Conservation And Conventional Tilled Plots." Planning Now For
Irrigation And Drainage In The 21st Century, Lincoln, Nebraska, 1988. (American Society Of Civil
Engineers, New York, New York, pp. 587-595).  1988.

       Abstract.   Carbofuran, alachlor, atrazine, nitrate and bromide (a tracer) wee applied to plots
with conventional and conservation tillage. Conventional tillage consisted of plowing, disking and
harrowing. In the conservation tilled plots, the sod was killed with "Roundup" and the corn seeded without
any further tillage.

       During the early part of the growing season the conservation tilled plots had a higher tile
discharge than those under conventional tillage due to dead sod cover that suppressed
evapotranspiration. Low concentrations of atrazine and carbofuran were found below the rootzone in the
conservation tilled plots starting  one month after application.  In the conventional tillage it was not until
late fall that some atrazine was detected below the rootzone.  Dye studies indicated that in the  plowed
layer of the conventional tilled plots water and solutes were in intimate contact with the soil matrix
promoting adsorption of the pesticides. The bromide tracer was not adsorbed and the  bromide
distribution with depth was similar for both tillage practices. Bromide was, therefore, a poor indicator for
predicting potential pesticide losses under different tillage practices. Nitrate was only found in the zone
that was never saturated.
Strutynski, B., R. E. Finger, S. Le and M. Lundt. "Pilot Scale Testing Of Alternative Technologies
For Meeting Effluent Reuse Criteria." Water Environment Federation 65th Annual Conference &
Exposition, New Orleans, Louisiana, 1992. (Water Environment Federation, Alexandria, Virginia,
pp. 69-79). 1992.

       Abstract.  The Municipality of Metropolitan Seattle  (Metro) has been investigating the potential
for reuse of the effluent from its treatment  plant at Renton for the last several years. The City of
Seattle's Water Department, a major water supplier for the area, joined with Metro in 1991  in the
evaluation and development of reuse options. These options include both nonconsumptive reuse such
as heating and cooling and consumptive reuse such as irrigation.
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       A pilot program was instituted in 1991 to identify a range of technologies capable of producing
reuse quality water from secondary effluent. Technologies investigated included additional chlorination
of the existing secondary effluent as well as filtration, ultraviolet disinfection without and with prior
filtration.  All process streams were monitored for variety of parameters in addition to coliform levels.
This paper presents the results of this testing.


Tim, U. S. and S. Mostaghiml.  "Model For Predicting Virus Movement Through Soils."  Ground
Water. V. 29, n. 2. pp. 251-259. 1991.

       Abstract.   A numerical model, VIROTRANS, is developed for simulating the vertical
movement of water and virus through soils treated with waste-water effluents and sewage sludges. The
expression describing transient flow of water is coupled with the convective-dispersive equation for
subsurface solute transport. The resulting methodology is a coupled set of partial differential equations
that describe the transient flow of water and suspended virus particle movement through variably
saturated media.  Solutions to the partial differential equations are accomplished by a Galerkin finite
element method.  Several example problems are used to provide a quantitative verification and
validation of the model. The model simulations are compared to an analytical solution and to
experimental measurements of soil moisture content and poliovirus 1 transport.  The comparisons show
reasonable agreement between model simulations and measured data. Sensitivity of the model's
prediction to variations in pertinent input parameters are also analyzed.


Townley, J. A., S. Swanback and D. Andres.  Recharging A Potable Water Supply Aquifer With
Reclaimed Wastewater In Cambria, California. John Carollo Engineers, Walnut Creek, CA. 1992.

       Abstract.   A proposed project in Cambria, a small unincorporated community in San Luis
Obispo County, involves recharging one of the community's domestic supply aquifers with reclaimed
wastewater.  This paper describes the advance treatment system, regulatory involvement, and public
acceptance issues.


Treweek, G. P. "Pretreatment Processes For Groundwater Recharge." Artificial Recharge Of
Groundwater. Butterworth Publishers, Boston, pp. 205-248. 1985.

       Abstract.   Unplanned, indirect wastewater reuse through effluent discharge to streams and
groundwater basins for subsequent downstream use by a wide variety of interests -- agricultural,
industrial, or domestic -- has been a long-accepted practice throughout the world. Many communities at
the  end of major waterways, such as New Orleans and London, ingest water that already has been used
as many as five times by repeated river withdrawal and discharge. Similarly, rivers or percolation basins
may recharge underlying groundwater aquifers with reclaimed wastewater, which is in turn withdrawn by
subsequent communities.  For example, the effluent from over 140 wastewater treatment plants partially
replenishes the groundwater tapped by the water supply system for London. This means effluent
disposal, known as unplanned, indirect reuse, has become  a generally accepted practice.

       Planned, direct reuse is practiced on a smaller scale for a limited number of purposes, primarily
agricultural and industrial.  The terms 'unplanned' and 'planned' refer to whether the subsequent reuse
was an unintentional byproduct of effluent discharge, or was designed as a conscious act following
effluent discharge. The planned reuse schemes discussed in this chapter incorporated wastewater
reclamation processes designed to meet not only effluent discharge standards, but also reuse standards
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 promulgated by health authorities.


 Troutman, D. E., E. M. Godsy, D. F. Goerlitz and G. G. Ehrlich. Phenolic Contamination In The
 Sand-And-Gravel Aquifer From A Surface Impoundment Of Wood Treatment Wastewaters,
 Pensacola, Florida.  Geological Survey Water-Resources Investigations Report 84-4230.  U.S.
 Geological Survey, Tallahassee, Florida. 1984.

       Abstract.    The discharge of creosote and pentachlorophenol wastewaters to unlined surface
 impoundments has resulted in ground-water contamination in the vicinity of a wood-treatment plant near
 Pensacola, Florida. Total phenol concentrations of 36,000 micrograms per liter have been detected at a
 depth 40 feet below land  surface in a test hole 100 feet south of overflow impoundment. Phenol
 concentrations in this same test hole were lest than 10 micrograms per liter at a depth of 90 feet below
 land surface.  Samples collected in test holes 1,350 feet downgradient from the surface impoundments
 and 100 feet north of Pensacola Bay, above and immediately below a clay lens, indicate that phenol
 contaminated ground water may not be discharging directly into Pensacola Bay.  Phenol concentrations
 exceeding 20 micrograms per liter were detected in samples from a drainage ditch discharging directly
 into Bayou  Chico.

       Microbiological data collected near the wood-treatment site suggest that anaerobic
 methanogenic ecosystem contributes to reduction in phenol concentrations in ground water. A laboratory
 study using bacteria isolated from the study site indicates that phenol, 2- methylphenol, and 3-
 methylphenol are significantly degraded and that methanogenesis reduces total phenol concentrations in
 laboratory digesters by 45 percent. Pentachlorophenol may inhibit methanogenesis at concentration
 exceeding 0.45 milligrams per liter.

       Data on wastewater migration in ground water from American Creosote Works indicate that the
 sand-and-gravel aquifer is highly susceptible to contamination from unlined surface impoundments and
 other surface sources. Groundwater contamination occurs readily in pervious sands and gravel within
 the aquifer where the water  table is near land surface. Coastal areas and valleys tend to be areas of
 ground-water discharge, and contamination of ground water in these areas may result in surface-water
 contamination.
U.S. Environmental Protection Agency Office Of Water, Office of Wastewater Enforcement and
Compliance, and Off ice of Research and Development, Office of Technology Transfer and
Regulatory Support. Manual: Guidelines For Water Reuse.  EPA/625/R-92/004. U.S.
Environmental Protection Agency, Washington, D.C. 1992.

       Abstract.  With many communities throughout the world approaching or reaching the limits of
their available water supplies, water reclamation and reuse has become an attractive option for
conserving and extending available water supplies. Water reuse may also present communities an
opportunity for pollution abatement when it replaces effluent discharge to sensitive surface waters.

       Water reclamation and  nonpotable reuse only require conventional water and wastewater
treatment technology that is widely practiced and readily available in countries throughout the world.
Furthermore, because properly implemented nonpotable reuse does not entail significant health risks, it
has generally been accepted and endorsed by the public in the urban and agricultural areas  where it has
been introduced.

       Water reclamation for nonpotable reuse has been adopted  in the United States and  elsewhere
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without the benefit of national or international guidelines or standards. However, in recent years, many
states in the U.S. have adopted standards or guidelines, and the World Health Organization (WHO) has
published guidelines for reuse for agricultural irrigation. The primary purpose of this document is to
present guidelines, with supporting information, for utilities and regulatory agencies in the U.S.  In states
where standards do not exist or are being revised or expanded, the Guidelines can assist in developing
reuse programs or appropriate regulations. The Guidelines will also be useful to consulting engineers
and others  involved in the evaluation, planning, design, operation, or management of water reclamation
and reuse facilities. In addition, a section on reuse internationally is offered to provide background and
discuss relevant issues for authorities in other countries where reuse is being considered. The document
does not  propose standards by either the U.S. Environmental Protection Agency (EPA) or the U.S.
Agency for  International Development (AID).  In the U.S., water reclamation and reuse standards are the
responsibility of state agencies.

       These guidelines primarily  address water reclamation for nonpotable urban, industrial, and
agricultural reuse, about which little controversy exists. Also, attention is give to augmentation of potable
water supplies by indirect reuse. Because direct potable reuse is not currently practiced in the U.S., only
a brief overview is provided.


Varuntanya, C. P. and D. R. Shafer.  "Techniques For Fluoride Removal In Industrial
Wastewaters."  Water Environment Federation 65th Annual Conference & Exposition, New
Orleans, Louisiana, 1992. (Water Environment Federation, Alexandria, Virginia, pp. 159-170).
1992.

       Abstract.  This paper will present data from several laboratory scale treatability studies for
fluoride removal from two industrial plant wastewaters. Additionally, limited plant data will be presented
from one facility.  Production at each facility involves the manufacture of zirconium tubes and the
manufacture of semiconductors. The zirconium tube manufacturing plant wastewater contains
approximately 15-20 mg/L fluoride  before treatment while the semiconductor facility contains
approximately 25 mg/L fluoride. The results of the studies show that fluoride can be reduced to as low
as 1 mg/L.  The paper will also discuss the effluent concentrations achievable from each treatment
scheme, as well as the chemical dosages required, and the process  equipment necessary in each
scheme.  The advantages and disadvantages of the treatment processes will also be evaluated in this
paper.  The objective of the paper will provide insight for defluoridation of wastewaters for given effluent
limitations.
Vaughn, J. M., E. F. Landry, L. J. Baranosky, C. A. Beckwith, M. C. Dahl and N. C. Delihas .
"Survey Of Human Virus Occurrence In Wastewater-Recharged Groundwater On Long Island."
Applied And Environmental Microbiology. V. 36, n. 1. pp. 47-51. 1978.

       Abstract.  Treated wastewater effluents and groundwater observation wells from three sewage
recharge installations located on Long Island were assayed on a monthly basis for indigenous human
enteroviruses and colrform bacteria for a period of 1 year. Viruses were detected in groundwater at sites
where recharge basins were located less than 35 feet (ca. 10.6 m) above the aquifer.  Results from one
of the sites indicated the horizontal transfer of viable viruses through  the groundwater aquifer.


Vecchioli, J., G. G. Ehrlich, E. M. Godsy and C. A. Pascale.  "Alterations In The Chemistry Of An
Industrial Waste Liquid Injected Into Limestone Near Pensacola, Florida."  Hydrogeology Of
Karstic Terrains: Case Histories. International Association Of Hydrogeologists, UNESCO, V. 1.
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 pp. 217-220. 1984.

        Abstract.   An industrial waste liquid containing organonitrile compounds and nitrate ions has
 been injected since June 1975 into the lower limestone of the Floridan aquifer at a site near Pensacola,
 Florida. Data from inorganic and organic chemicals, dissolved gas, and microbiological analyses of
 liquid backflowed from the injection well and of liquid sample from a nearby monitor well indicated that
 the injected waste liquid undergoes substantial chemical changes in the subsurface.


 Verdin, J., G. Lyford and L. Sims. Application Of Satellite Remote Sensing For Identification Of
 Irrigated Lands In The Newlands Project. 1987.

        Abstract.   As one element of Operating Criteria and procedures for the Newlands project in
 west-central Nevada, the Bureau of Reclamation has compiled an irrigation water rights spatial data
 base.  In 1984, color infrared aerial photography was obtained and used to identify irrigated lands in the
 project. The photo interpretations were digitized to integrate them with water right maps for the project,
 which had similarly been digitized.  Bench and bottom land designations, a soil type distinction of
 consequence for legal water entitlements, were recorded from maps as well.  The data base was used to
 calculate and summarize the tables, on a section-by-section basis, acreages of irrigated lands with water
 rights, irrigated lands without water rights, and non-irrigated water-righted land.  For the 1985 and 1986
 growing seasons, multispectral digital imagery of the project acquired by the Thermatic Mapper
 instrument on Landsat-5 was used to update the irrigated lands theme of the data base. Scenes from
 May and August dates of those seasons, chosen after consideration of the phenologies of the major
 crops in the project, were co-registered and used to derive multidate vegetation index (Kauth - Thomas
 "greenness") images. These derivative images were then interpreted at an interactive video display
 providing a variety of enhancement capabilities, such as zooming and contrast stretching, to identify
 lands whose irrigation status had changed. Revisions to the irrigation theme of the spatial data base
 were then made accordingly, as were modifications to the water rights coverage due to transfers between
 parcels of land.  New acreage tabulation s were prepared by digitally overlaying the revised coverages.
 In 1986, the SPOT-1 satellite was launched, and the higher resolution imagery available from this remote
 sensing satellite is currently being evaluated for use in the Newlands Project. Multitemporal greenness
 images are being processed for crop type identification, and multispectral images are being digitally
 merged with 10-meter resolution panchromatic images for improved interpretability.


 Waller, B. G., B. Howie and C. R. Causaras. Effluent Migration From Septic Tank Systems In Two
 Different Llthologies, Broward County, Florida. Geological Survey Water-Resources
 Investigations Report 87-4075. U.S. Geological Survey, Tallahassee,  Florida.  1987.

       Abstract.  Two septic tank test sites, one in sand and one in limestone, in Broward County,
 Florida, were analyzed for effluent migration.  Ground water from shallow wells, both in background
 areas and hydraulically downgradient of the septic tank system, was sampled during a 16-month period
from April 1983 through August  1984. Water-quality indicators were used  to determine the  effluent
 affected zone near the septic tank systems.

       Specific conductance levels and concentrations of chloride, sulfate, ammonium, and nitrate
 indicated effluent movement primarily in a vertical direction with abrupt dilution as it moved
downgradient. Effluent was detected in the  sand to a depth more than 20 feet below the septic tank
outlet, but was diluted to near background  conditions 50 feet downgradient from the tank. Effluent in the
limestone was detected in all three observation wells to depths exceeding 25 feet below the septic tank
outlet and was diluted, but still detectable, 40 feet downgradient.
                                             174

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        The primary controls on effluent movement from septic tank systems in Broward County are the
lithology and layering of the geologic materials, hydraulic gradients, and the volume and type of use the
system receives.


Wanielista, M., J. Charba, J. Dietz, R. S. Lott and B. Russell.  Evaluation Of The Stormwater
Treatment Facilities At The Lake Angel Detention Pond Orange County, Florida.  Report No. FL-
ER-49-91. Florida Department Of Transportation Environmental Office, Tallahassee, Florida.
1991.

        Abstract.   This is the final report on the use of Granulated Active Carbon (GAC) beds of
Filtrasorb 400 in series to reduce the Trihalomethane Formation Potential (THMFP) concentrations at the
Lake Angel detention pond, Orange County, Florida. The detention pond accepts runoff from an
interstate highway and a commercial area. Breakthrough time was estimated from laboratory analyses
and used to design two beds in series at the detention pond. Breakthrough occurred in the first  bed after
treating 138,000 liters of water. Exhaustion of the first bed was reached after treating 1270 bed  volumes
with a sorption zone length of 1.70 feet.  The TOC adsorbed per gram of GAC was 6.3 mg. The liquid
flow rate averaged 0.0011 cfs. Similar breakthrough curves for Total  Organic Carbon (TOC) and color
were also reported.  The used GAC can  be disposed of by substituting it for sand in concrete mixes.

        An economic evaluation of the GAC system at Lake Angel demonstrated an annual cost of
$4.39/1000 gallons to treat the stormwater runoff after detention and before discharge into a drainage
well. This cost could be further reduced  by using the stormwater to irrigate right-of-way sections of the
watershed. An alternative method of pumping to another drainage basin was estimated to be more
expensive.

        The underdrain network for  GAC system initially became clogged with the iron-and sulfur-
precipitating bacteria Leptotrix, Gallionella and Thiothrix. These bacteria were substantially reduced by
altering the influent GAC system pipeline to take water directly from the lake.  An alternate pipe system
used a clay layer to reduce ground water inputs and did not exhibit substantial bacterial growth.


Wellings, F. M. "Perspective On Risk  Of Waterborne Enteric Virus Infections." Chemical And
Biological Characterization  Of Sludges, Sediments, Dredge Spoils, And Drilling Muds.  ASTM
STP 976.  American Society For Testing And  Materials, Philadelphia, Pennsylvania,  pp. 257-264.
1988.

        Abstract.   A valid perspective  on the risk of waterborne enteric virus infections related to land
disposal of sludge must incorporate various parameters.  It is not enough to accept at face value the
predominantly negative findings from the relatively few scientific studies that have purportedly been
done to determine the fate of viruses introduced into the environment with the deposition of sludge.
Rather, it is incumbent upon interested parties, whether they are regulatory or scientific, to evaluate the
whole through a careful examination of the parts. This paper attempts to bring into focus the presently
available data on four major virological issues. These are the characteristics of enteric viruses which
enable them to survive wastewater treatment processes, problems associated with the accumulation and
interpretation of data related to viral  contamination of groundwater by sludge disposal practices,
problems associated with transfer to the  real world of data derived from laboratory- seeded experiments,
and problems related to the establishment of the role of enteric viruses in waterborne disease outbreaks.
Present data are insufficient for establishing the quantitative risk of waterborne disease because of the
land disposal of sludge.  However, there is some probability of groundwater contamination sufficient to
warrant a cautious approach to land disposal of sludge.
                                              175

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White, E. M. and J. N. Dornbush.  "Soil Changes Caused By Municipal Wastewater Applications
In Eastern South Dakota."  Water Resources Bulletin. V. 24, n. 2.  pp. 269-273. 1988.

       Abstract.  Wastewater from a municipal treatment plant was applied in rapid infiltration basins
for four years to determine a poorly drained soils effectiveness in removing influent N and P and the soil
changes that might limit their removal.  About half the total PO4-P lost from the influent was sorbed in
the upper 91 cm of the soil and the other half was sorbed by the soil below the perforated pipe, which
was used to  drain the basins and collect the effluent for analysis. Drying of the basin soils converted
more sorbed PC^-P to Ca phosphates but the total sorbed was about the same.  The influent N
decreased , probably by volatilization, because the two basins with surface soil lost soil N rather than
gained soil N. The soil total Ca, Mg, and K contents did not change significantly but Na increased
slightly. Changes in the characteristics of the soils were slight and would have little effect on the
longevity of a rapid infiltration basin.


Wilson, L. G., M.D. Osborn, K. L. Olson, S. M. Maida and L. T. Katz.  "The Ground Water Recharge
And Pollution Potential Of  Dry Wells In Pima County, Arizona."  Ground Water Monitoring
Review. V. 10. pp. 114-121. 1990.

       Abstract.  This paper summarizes a study to estimate the potential for dry- well drainage of
urban runoff to recharge and pollute ground water in Tucson, Arizona.  We selected three candidate dry
wells for study. At each site we collected samples of runoff, dry-well sediment, vadose-zone sediment,
perched ground water, and ground water. Water content data from vadose-zone samples suggest that
dry-well drainage has created a transmission zone for water movement at each site. Volatile organic
compounds,  while undetected in runoff samples, were present in dry-well sediment, perched ground
water at one site, and ground water at two sites. The concentrations of volatile organics (toluene and
ethylbenzene) in the water samples were less than the corresponding EPA human health criteria.
Pesticides were detected only in runoff and dry-well  sediment.  Lead and chromium occurred in runoff
samples at concentrations above drinking water standards. Nickel, chromium, and zinc concentrations
were elevated in vadose-zone samples at the commercial site. Of the  metals, only manganese,
detected at the residential site,  exceeded Secondary Drinking Water Standards in ground water.  It is
concluded that the three dry wells examined during this study are currently not a major source of ground
water pollution.


Wolff, J., J. Ebeling, A. Muller and H. Wacker.  "Waste Water Irrigation Suited To  The
Environment As Shown By The Example Of the 'Abwasserverband Wolfsburg1."  Hydrological
Process And Water Management In Urban Areas, Duisburg, Federal Republic Of  Germany, 1988.
(International Hydrological Programme, UNESCO, pp. 599-606).  1988.

       Abstract.  Changes in the chemistry of ground water by the influences of waste water land
treatment will be discussed by the research at the area of the 'Abwasserverband Wolfsburg', south east
Lower Saxony.  The results of a four-year research programme shows that, under certain conditions,
waste water land treatment can be realized in an ecological justifiable way.


Yurewlcz, M. C. and J. C. Rosenau.  Effects On Ground Water Of Spray Irrigation Using Treated
Municipal Sewage Southwest Of Tallahassee, Florida. Geological Survey Water-Resources
Investigation Report 86-4109.  U.S. Geological Survey, Tallahassee,  Florida. 1986.
                                            176

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       Abstract.   Increases in the concentrations of chloride and nitrate nitrogen in ground water have
resulted from land application of secondary- treated municipal sewage southwest of Tallahassee, Florida.
The increases occurred predominantly during periods of above normal application rates. This result is
based upon a data-collection program which began in 1972, 6 years after the initial application of treated
sewage.  The data collection period for this report is 1982 through June 1981.

       Although an estimated  minimum volume of 4,220 million gallons of treated sewage was spray
irrigated from July 1966 through June 1981, distortion of the local ground-water flow pattern did not occur
because of the high, natural recharge and high permeability of the limestone aquifer. Direct recharge
from the land surface to the Floridan aquifer system occurs by rapid infiltration through the sand
overburden and a discontinuous clay layer above the limestone formation.  Soluble constituents move
laterally and vertically with the ground-water flow pattern. Use of chloride as a tracer of water movement
indicates that treated sewage occurs at depths greater than 200 feet below land surface below the spray
sites.  The direction and rate of ground-water movement is southwesterly toward the Gulf of Mexico, at a
rate of approximately 5 feet per day, with significant downward movement also occurring.

       The most significant effect on  ground-water quality has been high nitrate nitrogen concentrations
which were detected between 1972 and 1976 when high volumes of treated sewage were applied for
experimental purposes. During this period, nitrate nitrogen concentrations in the upper limestones of the
Floridan aquifer system exceeded the maximum contaminant level of 10 milligrams per liter established
for potable water supplies. Computations indicate that if the monthly load of nitrogen does not exceed
130 to 180 pounds per acre, the concentration of nitrate nitrogen in the upper part of the aquifer will not
exceed 10 milligrams per liter.

       Other water-quality characteristics were not significantly affected by the application of treated
sewage.  Concentrations of trace metals including arsenic, cadmium, chromium, copper, iron, lead,
manganese, mercury, selenium, and zinc in ground water remained at background levels.
Organochlorine insecticides and chlorinated phenoxy acid herbicides were analyzed, but not detected in
18 ground-water samples collected in  1974 and  1978.  Concentrations of major inorganic ions in the
ground water likely are controlled by equilibrium conditions between the water and the aquifer matrix.
                                              177

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                                             181

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