EPA-600/2-76-105

  May 1976
Environmental Protection Technology Series
                            i> itv&r'wKf

*-£&*! &t >SHn/ «f •> 1 ^  J
                          AN  ECONOMIC  ANALYSIS  OF THE

        ENVIRONMENTAL  IMPACT  OF  HIGHWAY DEICING
                                                                     of-

                                                                     /"- ^ ~

                                                                     f'
                                            5: / > x * • I ..   *
                                            *^.  J»-K fe /     rf
                             SB»p«H!«nwrsf} ,». 11»
                                        1
                               %""  <^...

                               r C *  * v   .
                               s»   «»  -3
                                   jul'l..1'      J*"4               *i  " , "»

                                    f    Municipal Environmental Research Laboratory
                                   <*ll * '» »* *   V  ' •** '"«,  ,"n  , •»«•->-   <   j"^ -"

                                  ^igj  r  . v/ Office of Research and Development


                                         tls^KrffivIronniental "Protection Agency
                                                     ^£«'£ *  f nt. >.?•
-------
                 RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency,  have been grouped into five series. These five "Broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and  a maximum interface in related fields.
The five series are:                                               ;
     1.    Environmental Health Effects Research
     2.    Environmental Protection Technology
     3,    Ecological Research
     4.    Environmental Monitoring                            '.
     5,    Socioeconomic Environmental Studies

This report  has been assigned  to  the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment,  and methodology to repair or prevent
environmental degradation from point and non-point sources  of pollution. This
work provides  the new or improved technology required for the control  and
treatment of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

-------
                                             EPA-600/2-76-105
                                             May 1976
    AN ECONOMIC ANALYSIS OF THE ENVIRONMENTAL IMPACT

                   OF HIGHWAY DEICING
                           by
         Donald M.  Murray and Ulrich F. W. Ernst
                   Abt Associates Inc. •
             Cambridge, Massachusetts  02138
                 Contract No. 68-03-0442
              OMB Clearance No. 158S 74012
                     Project Officer

                     Hugh E. Masters
            Storm and Combined Sewer Section
              Wastewater Research Division
Municipal Environmental Research Laboratpry  (Cincinnati)
                Edison, New Jersey  08817
          U.S. ENVIRONMENTAL PROTECTION AGENCY
           OFFICE OF RESEARCH AND DEVELOPMENT
       MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
                 CINCINNATI, OHIO  45268

-------
                                 DISCLAIMER
This report has been reviewed by the Municipal Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or recommendation
for use.
                                      ii

-------
                                  FOREWORD
The Environmental Protection Agency was created because of increasing public
and government concern about the dangers of pollution to the health and
welfare of the American people.  Noxious air, foul water, and spoiled land
are tragic testimony to the deterioration of our natural environment.  The
complexity of that environment and the interplay between its components
require a concentrated and integrated attack on the problem.

Research and development is that necessary first step in problem solution
and it involves defining the problems, measuring its impact, and searching
for solutions.  The Municipal Environmental Research Laboratory develops new
and improved technology and systems for the prevention, treatment, and
management of wastewater and solid and hazardous waste pollutant discharges
from municipal and community sources, for the preservation and treatment of
public drinking water supplies, and to minimize the adverse economic, social,
health, and aesthetic effects of pollution.  This publication is one of the
products of that research; a most vital communications link between the re-
searcher and the user community.

The study contained herein involves an extensive examination of the costs
incurred by society as a result of the use of highway deicing chemicals.
The costs, which are examined separately for damage to each sector of the
natural environment and to manmade goods, are shown to be substantial.
                                       Francis T. Mayo
                                       Director
                                       Municipal Environmental
                                       Research Laboratory
                                       ill

-------
                                   ABSTRACT
This study involves an analysis of the cost of damages that res.ult from the
use of salt  (sodium chloride and calcium chloride) on highways to melt
snow and ice.  A large literature search and several surveys were carried
out to determine the types and extent of damages that have occurred.  The
report contains a Bibliography with over 320 references.       :

An in-depth analysis was performed on all of the data obtained.  The major
cost sectors examined were: water supplies and health, vegetation, highway
structures,  vehicles, and utilities.  For each of the sectors, a cost estimate
was developed.  The total annual national cost of salt related dametge approaches
?3 billion dollars or about 15 times the annual national cost for salt purchase
and application.  While the largest direct costs result from damages to vehicles,
the most serious damage in the long run seems to be the pollution of water
supplies and the degradation of health which may result.  It is, particularly
difficult to assign costs in this latter area and therefore the estimate may
substantially understate the actual indirect costs to society.

These findings indicate that the level of salt use should be reduc€*d.  The
amount of the reduction should be determined on the basis of local conditions.

This report was submitted in fulfillment of Contract No. 68-03-0442 by Abt
Associates Inc., under the sponsorship of the Environmental Protection Agency.
                                       iv

-------
                          CONTENTS
Abstract
List of Figures
List of Tables
Acknowledgements
SECTIONS

1.0      FINDINGS AND CONCLUSIONS
     1.1 Summary of Findings
     1.2 Conelus ions
 2.0
RECOMMENDATIONS
3.0      INTRODUCTION
     3.1 The Use of Salt for Deicing
     3.2 Summary of Approach

4.0      SALT RELATED DAMAGE,
     4.1 Damages to Natural Resources
     4.2 Damage to Man-Made Goods

 5.0      THE COST OF SALT  RELATED  DAMAGE
     5.1 Methodology
     5.2 Costs of Water Supply Contamination
     5.3 Costs of Damages  to Vegetation
     5.4 Costs of Damages  to Highway  Structures
     5.5 Costs of Automobile Corrosion
     5.6 Other Damages
     5.7 The Direct Costs  of Salt  Application
     5.8 Summary of Costs
                                              Page
                                              iv
                                             vii
                                             viii
                                              ix
                                               1
                                               1
                                               2
                                               5
                                               5
                                               8

                                              10
                                              13
                                              24

                                              43
                                              43
                                              48
                                              65
                                              68
                                              74
                                              88
                                              89
                                              89

-------
                        CONTENTS (Cont'd)
SECTIONS

6.0      BENEFITS OF ROAD SALTING
     6.1 Salt and Safety
     6.2 Time Savings

BIBLIOGRAPHY
APPENDIX A
APPENDIX B
Page

: 91
 91
 94

, 95
120

-------
                          LIST OF FIGURES
                                                      Page
FIGURE

 1.      Fate of Salt in the Environment

 2.      Massachusetts - Ground Waters

 3.      Massachusetts - Surface Waters

 4.      Connecticut - Ground Waters

 5.      Connecticut - Ground Waters

 6.      New Hampshire - Ground Waters

 7.      Rhode Island - Surface Waters

 8.      Example of Deck Spall on Underside of
         West Side Highway, New York City

 9.      Collapse of West Side Highway at Ganesvoort
         Street on 12/15/73, New York City

 10.     Typical Stringer Web Deterioration on
         West Side Highway Structure, New York City

 11.     Schematic Overview of Cost Generation
         Framework

 12.     Rhode Island - Surface Waters

 13.   .  Corrosion of Reinforcing Steel in Highway
         Structures

 14.     Hourly  Demand and Capacity

 15.     Cumulative  Demand and Capacity
11

16

16

17

17

18

18


31


36


37


44

49


70

73

73
                            Vll

-------
                           LIST OF TABLES
TABLE
                                                    1 Page
 1.      Dimensions of Costs Associated with Salt
         Contamination of Drinking Water           • ',  51
                                            i
 2.      Direct Costs Associated with Salt
         Contamination of Drinking Water Supplies     56

 3.      Costs of New Hampshire Well Replacement    •
         Program                                    :  60

 4.      Differences in Cardiovascular Death Rates
         for Different Levels of Sodium in Drinking
         Water (per 100,000)                        .  64

 5.      Basic Values of Shade Trees (For Perfect   [
         Specimen Shade Trees)                        67

 6.      Summary of Microeconomic Costs  ,             70

 7.      Estimated Depreciation Rates for Selected
         Cities                                       80

 8.      Cost of Automobile Depreciation              85
                           viii

-------
                           ACKNOWLEDGEMENTS
The contents of the report are a product of many contributors across
the nation, and from several foreign countries.  The project staff have
been impressed by, and greatly appreciative of, the concern on the part
of hundreds of individuals and agencies which have provided valuable
information.  Sincere thanks goes to all those who have helped make this
possible.

Special thanks go to Adrian Clary of the Highway Research Board and
Richard Hay of the Federal Highway Administration for their comments
on a first draft of the highway and bridge damage section.  Thanks also
go to Robert C. Terry, Jr. of Arthur D. Little and The Salt Institute
for their advice and assistance.  The City of New York provided some
very important reports on the damage to the West Side Highway.

This report was written by Donald M. Murray and Ulrich F. W. Ernst.
Research Assistance was provided by Judy Poole, Ramon Estrada and
Janice Darling.'  Advice given by Malcolm FitzPatrick was appreciated.
Thanks go to Robert C. Anderson for his contributions, especially in the
area of bridge and automobile damage, and to Gary J. Stensland for his
work on the atmospheric content of salt.  Mary Hobson displayed great
patience in typing many drafts during the production of this report and
her efforts are also appreciated.

The support of this effort by the Wastewater Research Division (Edison,
New Jersey) of the USEPA Municipal Environmental Research Laboratory,
Cincinnati, Ohio, and especially Mr. Hugh E. Masters, Project Officer,
for his guidance, suggestions and inputs, and thorough manuscript review
is acknowledged with gratitude.;
                                   IX

-------

-------
                               SECTION 1

                       FINDINGS AND CONCLUSIONS
1.1
      SUMMARY OF FINDINGS
There have been a substantial number of reports of salt related damage
in the literature.  Most of the reports are deficient in hard cost data.
Consequently, by examining different small subsets of the data, various
individuals have arrived at opposite conclusions: in some cases that
salt damage is insignificant and in other cases, that road salting must
be discontinued completely.  Examination of all of the literature and
contact with hundreds of persons and agencies who are aware of salt
related damage has led to the finding that> in general, the damages
are very large although not uniform across all localities.  Through
analysis of all of the available data, the best estimate  (in many cases
the lower bound) of the annual cost to the snowbelt states that results
from the use of road salt is as follows:
       Water Supplies and Health

       Vegetation
       Highway Structures

       Vehicles
       Utilities
       Salt Purchase and Application
                  Total
Total (in millions)

 $  150

     50

    500

  2,000

     10

    200

 $ 2.91 Billion
 Furthermore, heavy  salt use  in many instances upsets the natural ecological
 balance  resulting in  damages which cannot be assigned a dollar figure.
 This  is  one of  the  many reasons  that the above dollar amounts must be
 considered as lower bounds.  The most potentially serious of all these
 damages  are the irreversible ones, such as the risk of increased hyper-
 tension  that results  from the heightened levels of sodium in water
 supplies.   For  example, groundwater supplies have been most severely
 affected.   Over 90  communities in Massachusetts have one or more supplies

-------
with a sodium content greater than 20 mg/liter, the maximum ; allowed for
persons on low sodium diets.  Over 30 water supplies in Connecticut con-
tain more than 20 mg/1 sodium and the number is increasing. . As much as
5% of the population consuming water contaminated by road salt may be
adversely affected.

The use of salt for winter maintenance generally results in better trac-
tion on the highways, but because of a number of confounding factors,
especially driver behavior, the link between salt and safety has not been
proved.  While several studies have reported that salt reduces accidents,
the methods of data collection and analysis have been found to be mathe-
matically unsound.                                          •

Finally, carefully designed reduced salting policies seem to have gained
public acceptance as a result of public information programs.  The most
notable case is the State of Connecticut where state salt use was reduced
by 33% because of rising sodium content in water supplies.  There is
every reason to believe that the residents of individual cities and
towns or other states would accept a salt reduction if the salt related
damages were made known to them.

1.2   CONCLUSIONS                                           :

In the past a number of claims have attempted to downgrade the serious-
ness of road salt related damage by placing emphasis on the comparisons
of the effectiveness of salt and sand, or by concentrating on the lack
of importance of vegetation in comparison to human lives  (i.e., safety
on the roads).  Because these claims do not address the whole problem,
they are superficial, misleading, and in a few cases, irresponsible.
The facts are:
            Several states have experienced significant increases of
            salt in groundwater and surface drinking water supplies
            that have been directly linked to the use of deicing salts.

            In particular cases, the levels exceed Public Health Service
            safety standards set in 1962 and in most cases the levels
            exceed the standards set by leading researchers, heart
            specialists and the American Heart Association.:

            The cost in terms of permanent health degradation is extremely
            difficult to measure, but is likely to be very high.

            The cost of actual damage to vehicles, highways and struc-
            tures, utilities, and vegetation are immense.  The annual
            damage costs at a very lower bound, approach $3 billion.
            This "hidden" cost is almost 15 times the annual national
            budget for the purchase and application of road salt, and
            about 6 times the entire annual national budget for snow
            and ice removal.

-------
The implications of these facts are clear.  Without a doubt the most serious
problem is our water supplies.  While the cost of damage to bridge decks
and vehicles is high, but reversible, the damage to health may not be reversed.
We can no longer afford to ignore the fact that we are depositing large
quantities of salt into the water that nature provides us and upon which
are dependent every moment of our lives.  The most advanced medical research
indicates that water with more than 20 mg/1 sodium is unhealthy and detrimen-
tal to a substantial fraction of the population.  The American Heart Assoc-
iation supports this fact.  Disregard for the quality of drinking water in
this and any instance is extreme negligence and we must face the issue
squarely.  Road salt may be only one of the many serious pollutants in our
environment, but that is no excuse to allow the present situation to exist
any longer.  In order to avoid further damage and high costs, salt use for
winter .maintenance must be reduced in many areas.

-------
                                  SECTION 2

                               RECOMMENDATIONS
The level of salting should be reduced by an amount determined by local
conditions such as the effect of salt laden runoff on water supplies,  the
level of public demand for bare pavement, and the size of the winter main-
tenance budget.  Greater emphasis should be placed on non-chemical methods
of snow and ice control (such as increased plowing and sanding.)   Determin-
ation of the required level of bare pavement is a burden that should not be
the sole responsibility of highway maintenance departments.  The  depart-
ments should seek advice from all interested groups and the public at  large
in order to achieve the best possible level of road maintenance within
given environmental constraints.  Through public affairs programs, the
public should be made aware of the tradeoffs and alternatives involved.
Changes to winter road policies should have public support and should  be
given a thorough public announcement before they are commenced.

There should be a greater emphasis on the training of drivers so  that
they will have the ability to drive under conditions of snow.and  ice,  and
less emphasis on the concept of guaranteed "June travel in January".
Moreover, an operating policy to encourage motorists to stay off  the roads
during and immediately after storms would facilitate snow and ice removal.
Restricted driving under short term emergency snow conditions should be
considered.

The snow belt states should provide for testing of public and private
water supplies, and should provide funds for replacement of public and
private wells  (as has been done in the State of New Hampshire).  State
legislation should be passed allowing individuals to have standing in
court to sue for damages when water supplies show an abnormal and hazar-
dous increase in sodium content.  The law should place the burden of
proof on the highway departments that the cause was not from'road salt.
Finally, the states should consider instituting a requirement that all
salt users file an Environmental Assessment.

While these measures may seem burdensome, they are necessary in order  to
insure that we maintain our high quality of water and that large  costs
are not incurred as a result of winter highway policies.    ;

-------
                                  SECTION 3

                                INTRODUCTION
3.1
THE USE OF SALT FOR DEICING
Extensive use of salt, both sodium chloride (NaCl)  and calcium chloride
(CaCl2), for snow removal operations began during the early 1960s.   Prior
to that time highway maintenance departments depended primarily on  abrasives
such as sand and cinders, in combination with plowing, to clear snow and
ice from highways.   Salt was generally used as an additive to the abrasives
to prevent freezing.  However, from practical experience, maintenance
departments began to appreciate the effect that salt had on accelerating
the melting rate of ice and snow.  Through experimentation, maintenance
engineers learned that direct application of salt before, during and/or
after a snowstorm greatly facilitated their snow removal operations, both
in terms of time and in terms of budget.  Since that discovery, the obvious
has occurred.  The use of salt for snow and ice removal has grown rapidly,
in some cases by as much as 900% in the past 15 years (299).  The extensive
use of salt has been associated with a significant amount of damage.  While
there have been many reports on this damage, there has not been a compre-
hensive examination of the total impact of all salt related damage.

There is no question that salt is an excellent tool in snow removal opera-
tions.  There also is no question that in terms of time and budget  constraints
for snow removal operations alone, the usage of large quantities of salt in
conjunction with plowing is essential.  Highway departments, operating
under the goal of creating the safest driving conditions, believe that a
policy of maximum bare pavement in a minimum time is optimized through
extensive use of salt, given their budget constraints.  In fact, some high-
way departments, in their eagerness to perform well and meet their  goals,
have often used salt in an inefficient manner.  This has largely been
eliminated now by education and understanding as a result of activities of
the Salt Institute  (312,313), the Environmental Protection Agency  (304, 310),
the Massachusetts Special Commission on Salt Contamination  (4) and  many
others  (see Bibliography:  Maintenance Procedures and Regulations).  The
result has been a more effective use of salt with essentially no reduction
in its level of usage  (288, 298, 290).  Total salt use for snow and ice
removal in this country now stands at approximately 9 million tons  each
year.  As the number of miles of highways increases, so also.can we expect
the amount of salt usage to increase if we continue with our present policy
(and if no alternative method of snow and ice removal is found).

-------
The concept of June travel in January, better known as the "bare pave-
ment policy," has led the highway departments and the publib to the
situation in which we currently find ourselves.  This situation; has
become increasingly complicated over the past 10 years, and especially
during the past 4 to 5 years, because of the growing number of reports
of damage to water supplies, vegetation, and the very vehicles and
highways that originally served as the only focus of attention.

The concern over salt related damage has been increasing rapidly,
probably exponentially, as the large (but only representative)
bibliography at the end of this report demonstrates.  The reports
on instances of damage are extensive and well documented.  There have
been several excellent works done to summarize these reports  (1,4,15,
16,26,38,42) and there have been many excellent in-depth studiess on
certain areas of damage (see Bibliography).  Probably the best
example of the latter is the work done for the Massachusetts Special
Commission  (4) and the follow-up by Robert Terry (53).  Upon careful
examination of all these studies.and the other literature which has
been reviewed, one can only come to the conclusion that the, problem
is potentially very serious.  The situation has required a very
careful assessment and the current guidelines under which snow
removal procedures operate requires thoughtful consideration.

It is in this context that the idea for this project was formulated.
Previous studies, as thorough as they were, did not assess the entire
problem of damage in comprehensive terms including an economic
analysis.  Logically, no amount of damage claims, without the necessary
economics, could enable a rational salting policy to be determined,
except in the most extreme cases.   Without such an economic analysis,
no alternative to salt, whether it be more snow left on the highways
or a more expensive replacement for salt, could ever be economically
justified.

Consequently this analysis of damage from road salt was undertctken in
order to assess the situation in the best possible manner.  In all
phases of the study there has been a constant effort to make the
analysis quantitative.  In some instances, because of the lack of cost
data, this has simply been impossible .   However in these cases every
effort to perform an unbiased qualitative assessment has been made.

The authors have been impressed not only with the extensive reports
of damage and the cost of that damage, but with the extensive amount .
of damage in one sector.  Rusted vehicles and bridges, while costly
can be replaced.  Damaged vegetation can be ignored by those who do
not incur the cost.   But pollution of our water supplies is a serious
matter.  This is not to say that all road salt usage leads :to water
pollution, but it has in many instances.  The medical implications
of salt in drinking water is not a matter to be taken lightly.
Because of many unknowns, the economic analysis of the damage to water

-------
 supplies is not able to point out how potentially serious the problem
 may be.  However each reader, knowledgeable of the facts on road salt
 damage in our environment, must make a decision for himself.  Hopefully
 in this way a rational solution will be found, and serious damage to our
 environment will be prevented.

The fact that damage from salt has reached the magnitude that it has
 should come as no surprise to anyone who understands the way in which .
 our current situation has evolved.  Highway maintenance departments
have as their primary goals the requirement for providing maximum safety
 and convenience on the highways.  The departments have performed well,
 especially considering the complexities involved in snow and ice removal.
While the current practices may be near optimal in terms of the department
 goals (and the highway budget constraints), in many locations the prac-
 tices are far from optimal in terms of our whole environment, man-made
 and natural.  This situation has occurred primarily because  (1) those
 who determine present maintenance policies are largely unaffected by the
 adverse environmental conditions  (that is, they do not incur the full
 cost of the damage),   (2) legal liability in some instances may have
 forced highway departments to give undue weight to accident prevention
 and   (3) there have been no outside forces to regulate the department's
 activities.  The result is a prime example of a situation in which exter-
 nal diseconomies  (social costs not borne by those making decisions as to
 the level of activity) lead to a failure of unregulated markets to achieve
 efficient outcomes.  Determining the precise level or combinations of
 winter maintenance policies that maximizes social well being within cer-
, tain constraints is the crux of the problem.  Theoretically, at least,
 this is accomplished by assigning prices to the various social and envir-
 onmental values and choosing that outcome which maximizes total net value.
 However, as the presentation and analysis in Sections 4 and 5 demonstrate,
 it is not possible to assign exact costs to all items because their value
 is subjective.  It is especially difficult in cases where irreversibilities
 are involved, such as with permanent health damage and vegetation death.
 It is interesting to note that the concept of "public pressure for bare
 pavement" may have evolved simply because the public was unaware of
 environmental damage and thought that more bare pavement resulted only
 in a small increase in the maintenance budget.  This attitude seems to
 be rapidly changing as the public becomes more aware of the need for a
 sound environment.

 An observation of public opinion has surfaced as a result of a large scale
 survey concerned with road related issues in Pittsburgh.  (69)   Question
 33 in that survey asked, "Would you be willing to see cinders or sand used
 as an alternative to salt if less road deterioration would result?"  A
 "yes" response was given by 73.3%, a "no" response by 24.6%, and no
 response by 1.8%.  Question 46 asked, "If it were shown that salt caused.
 serious damage to your car, would you be in favor of discontinuing the
 use of salt?".  A "yes" response was given by 69.6%, a "no" response by

-------
 26.8%, and no response by 3.6%.  Although the phrases "less road deterio-
 ation" and "serious damage" are not defined in terms of cost, and although
 the respondents may not have been fully aware of the impact that salt reduc-
 tion may have on snow removal or highway budget,these figures still seem
 to indicate that the "public pressure" may not be as unanimous as is gene-
 erally thought by the maintenance departments, especially considering that
 only one cost sector was mentioned in each of the two questions.  This is
 particularly true when the public is informed of the tradeoffs in terms of
 environmental damage.  As a result of road salting contamination of many
 water supplies, the state of Connecticut has developed a differential salting
 policy with a total reduction in salt use of one third.   Through public
 information programs and the resulting public awareness, the policy change
 seems to have been favorably received.  There is every reason to believe
 that a rational  and holistic salting policy would be welcomed by every
 community.

 Section 4 of this report presents the evidence on the link between road
 salt and damage, and demonstrates the extent of that damage. ; Section 5
 contains a thorough economic analysis of the damage and a summary of the costs
 involved.

 3.2    SUMMARY OF APPROACH

 This study involved the collection of a great deal of material, both from
 the literature and through personal contacts.  Subsequently this material
 was examined for its validity and thoroughness, forming the basis for analy-
 sis.  Assessment of this material, in both quantitative and qualitative terms,
 was then undertaken.                                         ;

 3.2.1  Literature Review, Surveys, and Personal Contacts

 During the course of the project a complete review of the literature on snow
 and ice removal, salt use, and salt damage was made and the most relevant
 documents, over 450 in number, were obtained (out of an estimated 700 or
 more).  Each one of these documents was carefully screened for its validity
 and relevance and over ;300 have been retained in a bibliography at the end
 of this report.

 The second portion of the research involved the mailing of surveys and
 letters to universities, Public Works Departments, Public Health Departments,,
 and water companies.  There were over 100 respondents who indicated that
 they had incurred damage, knew of damage in their area,  or provided us with
 documents or contacts relating to salt related damage.  Follow up was done
 in many cases in order to clarify responses or obtain further information.

 As a result of the literature and surveys, close to 200 personal contacts
 were made either by letter or phone.  Almost all of these contacts provided
 up-to-date information on salt related damage;  as in the case of the liter-
 ature, and the surveys, "hard" data on costs of damage was minimal.

Finally, all of the material gathered from the search and surveys was reviewed
 and evaluated.   This forms the basis for the presentation on salt related
damage in Section 4.                                         :

                                      8

-------
2.2.2   Approach, to Analysis

Since the study was essentially restricted to readily available data,
either in published form or in the form of accessible records, the
analysis of the 'economic costs of damages attributable to the use of
deicing salts was constrained by the opportunities offered by the
available data.  In order to generate key points of reference, the. cost
analysis was based on a general model which expressed the expected (or
average) annual cost in a particular damage category as the product of
the expected magnitude of total damages (which in turn is the product
of the probability of occurrence times the damage per occurrence) and the
cost per "unit" of damage.

This general cost model provided the basis for examining the literature
and other materials that had been accumulated in the study.  Considerable
efforts were undertaken to adapt the available information to. fill the
data needs of the study.  However, in most cases, the estimation pro-
cedures used to quantify certain parameters of the cost function were
too broad, given the nature of the available data.  In these cases, costs
were estimated on an ad hoc basis, e.g., by a weighted extrapolation of
detailed cost data for a particular state or region.

The analysis comes closest to the ideal in the case of automobiles, in
which the study could draw on previous work in the appropriate direction
by one of the consultants to the study.  The analysis of the costs of
accelerated corrosion of automobiles used detailed data on depreciation
rates in a significant sample of metropolitan areas, and estimated the
net effects of deicing salts through multivariate analysis.

-------
                                SECTION 4
                            SALT RELATED DAMAGE

As stated in Section 3.1, the purpose of this study has been to factually
ascertain the types, extent, and monetary value of damage that has taken
place in the total environment as a result of road salting.  The purpose
of this section of the report is to present a summary of the material
which has been gathered from an extensive literature review and from
personal contact with highway officials, public health officials, researchers,
manufacturers, utility companies, and others.  In the individual sections
on damage, reference is made to major studies and in some instances- to
specific research, but space simply does not allow an examination of all
of the documents listed in the Bibliography.  The presentation is primarily
centered around an explanation of how damage occurs, accompanied by actual
case examples.

It is essential to have a basic understanding of the paths that salt can
take through the environment.  All salt applied to the roads will eventually
end up in the ocean  (or in rare cases in underground pools of]water such
as fossil geologic water supplies) or will be stored in the environment
for an indefinitely long period of time (chiefly in soils). Between the
time of its application and the time of its eventual storage, salt is
capable of upsetting many ecological balances.  Once salt has been applied
to a highway, it is dispersed into the environment in a number of different
ways.   (See Figure 1)

Splash —                                                    ;

As vehicles pass over the salt solution, some of it will be splashed
onto the surrounding roadside.  The salty water will then percolate
downward into the ground.  Depending on the type of soil,  some fraction
of the sodium ions  (or calcium ions in the case of calcium chloride)
will bind with the soil.  The remaining sodium and chloride ions will
then be available for uptake into vegetation or will eventually enter
into the groundwater supply.  Salt solutions may also be splashed
directly onto roadside vegetation.

Runoff —

Solutions of highly  concentrated  salt may also run off  the highway
directly onto the surrounding roadside causing problems as outlined
above,  or it may be  carried in storm drains or gutters  as  runoff to
another location.  Such  runoff can also damage vegetation, enter into
groundwater supplies, or enter into surface waters, such  as streams,
rivers, ponds, lakes, and reservoirs.  Runoff has been  observed with
                                       10

-------
                            ATMOSPHERIC
                          REDISTRIBUTION
FALL-OUT OR
PRECIPITATION
                                                              WIND
                                                       EVAPORATION
                                    PICK-UP
                                    DISCARD
                                                           LEACHING
                                      SPLASH  &
                                      PERCOLATE
               DISSOLVE  &
               RUN-OFF
        STREAMS
    /  1  V"-
   /     \   \
RIVERS  1             -x
  ,A    Y
      LAKES
                        SOIL
                      BINDING

                        NA+
                        CA++
                                 Cl
                             GROUNDWATER
                                                 UPTAKE INTO
                                                     PLANTS
                                                            \
                                                             CHRONIC
                                                             EFFECTS
 OCEAN
    WELLS
WATER  SUPPLIES
GEOLOGIC WATER
     "I
   STORAGE   .
                                                     TOXIC
                                                     EFFECTS
                                                       DEATHS
                                                      (PLANTS)
                                          (Source:  Adams, Franklin
                                          S.,  "Highway Deicing Salts
                                          are  Potential Environmental
                                          Contaminants," Farm
                                          Economics, Pennsylvania
                                          State University, University
                                          Park, Pennsylvania (1973).
             Figure 1.  Fate of Salt in the Environment
                                   11

-------
concentrations as high as 35,000 mg/1  (325), approximately the same
concentration as ocean water.

Pick Up and Discard
                                                           I
In many areas salt-laden snow may be scooped up and carried by truck
to another location.  Large quantities of such snow may contain a great
deal of salt.  Depositing the snow anywhere other than in the ocean or
in an already highly polluted river will very likely lead to severe
groundwater damage and/or vegetation decline.

Atmospheric Redistribution

Road salt can enter into the atmosphere via the dispersion of small
droplets when cars and trucks pass over roads covered with a salt solu-
tion.  The larger drops of salt solution, referred to as "splash", will
fall out very near the highway (probably within a maximum of about 100
meters).  The smaller droplets will evaporate to an equilibrium size
consistent with the ambient relative humidity and be dispersed over a
large area.  If the ambient relative humidity is near 50% or less, the
solution droplets will evaporate to a dry salt particle whose very small
size will be a function of the highway salt solution concentration.
(322)  Also the dry salt residue remaining on the highway after the mois-
ture has evaporated can be scattered into the air by the passage of
vehicles.  Calculations by Stensland (324) have shown that about 1 to
1.5% of the road salt is passed into the atmosphere.

Before turning to the discussion of specific damage, it is important to
separate out the effects of road salt from the effects caused by salt
spray from the ocean.  Analysis of precipitation chemistry data by
Stensland (321, 322, 323) has shown that during the winter months in
locations where road salt is used, salt water spray from the ocean
(larger droplets that fall out r.apidly) dominate over road salt, spray
only in very close proximity to the coast.  The affected range is any-
where from a few hundred meters to a few kilometers depending on geo-
graphic and climatic conditions,  especially wind speed and direction.
Furthermore, the atmospheric content of salt particles will be dominated
by road salt sources more than 10-50 kilometers from the ocean, the dis-
tance again depending on geographic and climatic conditions.  Since the
amount of road salt and ocean salt in the atmosphere is very small in
comparison to the total amount of salt entering into the environment,
it must be concluded that in areas where road salt is used, the sea salts
become a dominant factor only in very close proximity to the ocean.
Examples in which sea salt would prevail are: bridges or other struc-
tures which pass over or are directly adjacent to the ocean and which
receive salt spray; vehicles which are parked along the ocean front.
The conclusion is that for all the areas where road salt is' used, sea
salt is a significant cause of damage in a very small fraction (1% or much
less) of the cases.
                                    12

-------
In addition to damage to the natural environment, man-made goods also
receive substantial damage from road salt.;  Vehicles passing over the
salt solution on the highway receive a spray of a highly concentrated
salt solution, depositing the salt on the metal surfaces where it will
remain and cause accelerated corrosion.  Splash from vehicles and
direct runoff can coat highway and surrounding structures with a salt
solution, making those structures more vulnerable to corrosion.  Seepage
of the salt solution through pavement  (or cracks in the pavement) will
eventually cause damage to the roadway.  Runoff and percolation will
allow the salt solution to eventually attack underground wires and
pipes, again accelerating corrosion and providing problems for industrial
users.

4.1   DAMAGES TO NATURAL RESOURCES

Mention of damage from road salt to natural components of the  environ-
ment has been frequent in the literature.  There is an abundance of
information on the means by which the  damage occurs and numerous reports
of specific damage cases and, in some  instances, the cost incurred.
Nevertheless, the proponents of salt use have  continually opposed the
significance  of such findings and the  subject  is usually dismissed with
responses  such as  "the value of a..tree does not compare to  the value of
human  life."  Examination of the literature  reveals  that damage to vege-
tation, while extensive and costly, is not  the major component.  The
real  concern  is over contamination  of  water supplies and the resultant
impact on  human life.

In this section,  the nature and extent of  salt related damage to natural
resources  will be examined.   The  fact  that there is a  link  between  road
salt  and damage has  been proven throughout the literature.   This section
serves to summarize  the established research.

 In general,  salt damage to natural  resources  is usually characterized
by the fact that it is  either irreversible, 'too costly or difficult to
reverse,  or only the passage  of time will allow the effects to disappear.
 There is a significant amount of  risk involved when irreversibilitv is
 an issue because the true meaning of the damage may only become fully
 known at a future time,  at which point it is too late to make a change.

 Assessment of damage to natural resources from road salt has always been
 a difficult problem.  Not all the processes by which damage occurs  or
 the exact relationship between salt use and damage are known, thereby
 making assignment of damage difficult.  The effects of salt in nature are
 often cumulative and therefore require lengthy studies for complete
 understanding.  Finally, because the concept of irreversibility is so
 little understood, there is often disagreement over the cost of damaged
 goods, making it difficult to assign costs.  The cost analysis of
 damage to natural resources which appears in Section 5 is conservative.
 The cost figures which are developed provide a lower bound; actual costs
 may actually far exceed these numbers.
                                     13

-------
 4.1.1  Water Supplies (Drinking)  and Health

 The contamination of water supplies is possibly the most serious  damage
 that results from the use of road salt.   Salt can enter into  ground-
 water supplies as it percolates down through the soil.   It  can  also enter
 into surface supplies as direct runoff from  highways.   Processing water
 to remove salt is an extremely expensive  and complicated matter,  and  is
 therefore rarely done.   Typically,  the safest means of  preventing the
 salt from reaching water supplies  is to catch the highway runoff  and
 direct it to a high  flow stream or river  which eventually reaches the
 ocean without entering into another water supply.   While provisions for
 runoff can be provided for new highways,  the cost of the provisions must
 be considered.   Such design has not been  incorporated into  a majority
 of the existing roadways,  and to do so now would be very costly,  if even
 possible.

 The concentration of sodium chloride in the  groundwater  is  a function
 of many factors,  most notably:   1)  the amount of salt applied to  the
 highway and  distance from the groundwater; 2)  the type,  frequency
 and quantity of precipitation;  3)  the  type of soil  and geologic
 material;  4)  direction  and rate of  flow of the groundwater;•and 5) the
 highway drainage  design.

 The concentration of sodium chloride in surface waters is also
 dependent on many factors, but primarily  a function  of:  1)  the amount
 of salt applied to highways which eventually  reaches the body of
 water;  and 2)  the volume  of  flow of  water into and out. of that body.
 Depending on the  rate of  flow,  some  surface waters are able to handle
 large  quantities  of  salt without a dangerous  increase in the equili-
 brium  level  of  sodium and  chloride.  Consequently, the effect on
 groundwater  is  usually more significant and possibly more serious
 because of the  slow movement of the water involved.  While some
 groundwaters  show a  significant movement within a matter of months,
 in some cases the time required for  the water surrounding a ^ell field
 to change may be  on  the order of years.  Consequently,  the ground-
 water  sodium and  chloride  levels typically show a lag in response
 to the actual date of salt application.  Surface waters are  jgenerally
 affected much more immediately.                             >

 The reports of  infiltration of  road salt into drinking water supplies
 are numerous and growing  (see Bibliography - Water).  Some of the
 first  cases of serious salt infiltration were found to have  been
 caused by improper salt storage facilities.  It was assumed  for some
period of time thereafter that most salt pollution was  the result of
 poor storage.  It has been shown that this is not the case.   In fact
most salt pollution that is presently occurring is apparently  caused
by  runoff from streets and highways  (53, p.  25).             \     •

The details of salt contamination in various  parts of the country have
been extensively recorded.  Since the literature is filled with  some
                                   14

-------
outstanding works on this subject, this section does not attempt to
review or mention all of the findings.  However it does contain an
updated report on the trends for some of the New England states.  The
reader who wishes to substantiate the findings should refer to the
literature, most notably the work by the Massachusetts Special
Commission  (4), EPA  (15), Terry (53), Hutchinson (95), the Massachusetts
Department of Public Health  (101), and Motts  (104).

Sodium and chloride content in water is measured in terms of milligrams
per liter  (mg/1) or, equivalently, parts per million  (ppm).  Until
several years ago, chloride tests were easier to perform than sodium
tests and therefore the older literature generally refers to salt in
terms of chloride levels.  Measurement of sodium in addition to chloride
is now universal.

A portion of the sodium entering water supplies through the ground is
usually bound into the soil so that not all of the sodium reaches the
groundwater.  In Massachusetts the ratio of sodium to chloride in most
public supplies has been- reported to be between 1:3 and 2:3 (53).  Thus
a water supply which has reached the limit of 250 mg/1 chloride may con-
tain between 83 and 167 mg/1 of sodium.  There are currently no federal
guidelines on the allowable level of sodium in drinking water supplies.
However for chlorides, the U.S. Public Health Service recommended in 1962
a maximum safe level of 250 m/gl.  In 1968, the Federal Water Pollution Con-
trol Administration advised a  maximum "desirable" chloride level of 25mg/l.

Some of the most recent data on water supplies show that the trends in
chloride and sodium content are in most cases still, increasing, while in
other cases remaining nominally stable or in equilibrium.  The accompany-
ing graphs  (see Figures 2, 3, 4,  5, 6, and 7) show the latest average
trends for four New England States.  The sodium content could be estimated
at between one-third and two-thirds the level of chloride given in these
graphs.  Prior to 1940, all Massachusetts data indicated chloride content
less than 10 mg/1.

Initial examination of the most recent Massachusetts data  (285, 326) reveals
that there appears to be a slight decline in the number of communities with
one or more public water supplies containing sodium above 20 mg/1:
        1970

         69
1971

 77
1972

 96
1973

 95
1974

 90
However, the figures for 1970-1972 period were established by Robert Terry
 (53), and there may be a slight difference in the methods of analysis.
Also salt storage  facilities have been improved over the past few years,
possibly accounting for the small decline.

Richard S. Woodhull, head of the Water Division of the Connecticut Depart-
ment of Health, reports that most water  supplies in Connecticut have been
                                     15

-------
                                                        <
O  B
                                                                IO
                                                                in
                                                                10
                                                               -3;
                                                                          (0
                                                                         -P
                                                                         -P  -P
                                                                         ,C!         &
                                                                o
                                                                m
                                                                in
                                                                         CO
                                                                         UJ

                                                                o       =J
                                                                         CM    10    =
                                                                                            O
                                                                                                     en
                                                                                                      m
                                                                                                      s
                                                                                                      m
                                                                         tn
                                                                                      m
a)
•a
o H
                                                       V
                                                                m
                                                              _ o
                                                                m
                                                                m
                                                                m
                                                                o
                                                                in
                            to
                                                                          I

                                                                          CO  M
                                                                         -P  !-l
                                                                         -P  OJ
                                                                          (U  -P
                                                                          co  nj
                                                                          S'S
                                                                          co  3
                                                                          CO  O
                                                                          (d  M
                                                                         S  <3
                                                                         Cn
                                                                        •H
                                                                        Pq
                                                                                !     I
                                                                                i      I
                                                                                                     PL,
PQ
                                                  16

-------
 (U
•d
•H
 M
 O
\
\ \
\ \
•\. \
N \
\
•
\
\ (
\
\ 1
\ I
1 1
• 	 .-- 	 , 	 . 	 . | ,
~T I I »— r 	 , — M
8 ? S 8 2
1
1
1

1

i







-> 's
4J
m &
""W 1
3
o
o ^
1 ^
o
in -H
m t i
u
(U
o . §
in §
in ^
M
•_? 'fe
rH
                                                                                    o
                                                                                    CO
                                                                                    a.
                                                                                    2
                                                                                    O
                                                                                    31
                                                                                          UJ
                                                                                          UJ
                                                                                          cc
                                                                                          CD
                                            CD
                                            2

                                            X
                                            CO
          O
          CC
          o
          u.
          cc
          UJ
          cc
          UJ
          t-
                                    1
                                     (D
                                     tn
                                                                                                                    en
                                                                                                                    CN
                                                                                                                    §
                                                                                                                    M
                                                                                                                    M-i

                                                                                                                    C
                                                                                                                    O
                                                                                                                    -H
                                                                                                                    CO
                                                                                                                    tn
                                                                                                                    •H
                                                                                                                    fi
                                                                                                                    O
                                                                                                                    •H
                                                                                                                    4J
                                                                                                                    (d
                                                                                                                    D
                                                                                                                    -H
                                                                                                                    iw
                                                                                                                    •H
                                                                                                                    •o
                                                                                                                    •p
                                                                                                                    •H
1'i
    \l
                                                             in
                                                             O
                                                             CD
                       0)
                      -P
                       rd
/ •
/
\
\
\
:
i •
1 ;
0
1
ft!



_ uj
—jo

_ in
in
~_ro
r-]

                      0)
                      c
                      fi
                      o
                      o
                                                                    Dl
                                                                    •rH
                                                                                 2
                                                                                 o
o

 I
 I
 I
 I
 r
 I
      o

i    I
CC ,   1J
:D    _J
o    uj

 I      1
 I      I
UJ
_J
_J

>
Q
ce
<
N!
<.
^
                                                                                 -s
                                                                                 Q)
                                                                                 Cn
                             Ti
                              0)
                             4J
                              S
                             •H
                              M
                              ft
                              
-------
                                                                                     in
                                                                                           1   a
                                                                                          '    <
                                                                                          H  
          00
                               CD
                                                                                                       fe
                                                              18

-------
showing a continually growing content of sodium chloride*.  A few
supplies have appeared to level off, probably in response to the 33%
cut in the state's use of salt.  (This cut was initiated because of
salt infiltration.  Some cities and towns have followed the state's lead).

In 1964 the State of New Hampshire established the Special Services
Division for the purpose of replacing wells contaminated by salt.  The
budget for the Division had been set at $100,000 for 8 years.  In 1974
and 1975, it was raised to $200,000, apparently to cover the cost of
increasing well damage.

Although the trends appear ominous, there are many who claim that the
current levels of sodium and chloride in the water supplies are not a
problem.  An early argument was that the level of salt was below the
taste threshold, and therefore safe.  Such an argument does not consider
the fact that there are highly poisonous chemicals which are either
tasteless or odorless.:  The claims by salt interest groups that concen-
trations of chloride as high as 2,000 mg/1  (between 667 and'1,333 mg/1
sodium) are not harmful  (42) are not supported by experimental data; in
fact, the scientific evidence  is totally contrary.

For some years now, medical research has established that intake of
sodium chloride is a critical  factor, affecting many health conditions,
including hypertension, cardiovascular diseases, renal and liver dis-
eases and metabolic disorders  (135).  Intake of salt also presents a
danger to a large percentage of pregnant women  (135).- Consumption of too
much salt can generally contribute to hypertension  (and eventually con-
gestive heart failure), poor circulation, and stress on the internal
organs  (132, 133, 134).  The most recent research has further confirmed
the link between  salt and hypertension, and between salt and the other
diseases and problems mentioned above  (134,  138,  139, 140).

As mentioned earlier, there is no public health standard for sodium in
water.   However,  the American  Heart Association  (19), backed by many
leading  medical researchers and physicians,  has recommended a limit of
22 mg/1  sodium in drinking water for patients whose diets are restric-
ted to  less than  500 milligrams of  sodium per day  (19, 135).**  Accor-
ding to  recent estimates approximately  23 million Americans are
   Personal Communication,  July 2,  1975.
 **Note for example that a  person restricted to 500 milligrams of salt per
 day who consumes 3 liters  of water (including cooking purposes)  containing
 100 mg/1 of sodium will be consuming 60% of his allowed daily intake.
 Since most foods contain some sodium, it is impossible at this level to
 prescribe a diet which would supply enough food (natural and unsalted) with-
 out causing the person to  exceed his allowed intake.   (141).  The 22 mg/1
 guideline has been established to allow a patient to maintain an adequate
 diet.
                                      19

-------
 suffering from hypertension and should restrict  their  sodium  intake
 (132).   This group,  together with other persons  who  should  restrict sodium
 intake  to 20 mg/1 comprise at least 20 to  25% of the population, with
 some researchers claiming the percentage to be as high as 40% (138).
 Unfortunately,  many  of those who should restrict their salt intake are not
 aware that their life is  at risk and therefore consume much more salt
 than they should.  Therefore for a particular individual, water with a
 sodium  content of more than 20 mg/1 may not present  a  significant danger.
 However,  such water  is potentially harmful to those  persons on low sodium
 diets (approximately 4-5%).   In addition,  further education of the public
 will undoubtedly result in greater awareness of  hypertension  and a greater
 percentage of the population will restrict their salt  intake.  Since
 complete reversal of the  sodium trends might take years once  action is
 taken,  more people are endangered than just those currently on salt
 restricted diets.

 Furthermore, one must consider the remainder of  the  population which is
 not yet hypertensive or diseased.   Dr.  Lewis Dahl, who has  researched
 salt and hypertension for years, has written that heightened  intake of
 sodium  from the time of infancy is unhealthy  (134).  Dr. Lot  Page,
 who has been involved in  some of the most  extensive  studies on hyper-
 tension and is currently  Chief of Medicine at the Newton-Wellesley
 Hospital in Newton,  Mass., has written that man  was  not meant to
 consume salt other than what is to be found in natural food sources and
 the more salt that is consumed, at all times in  life,  the higher is the
 probability of eventual hypertension.  Research  does show that the
 consumption of excess salt during infancy  may lead to  hypertension later
 in life (140).   The  two facts that (1)  salt has  been linked with hyper-
 tension and, (2)  that blood pressure is the chief indicator of life
 expectancy (for both physicians and insurance companies) can  lead
 to no other conclusion than road salt pollution  of our water  supplies
 is presently a highly dangerous situation.  While the  use of  salt on
 food is optional,  consumption of salt in^.the watervis  obligatory.
 Most serious of all, tne  presence of sodium in water is unknown to most
 of those who consume it.   Dr. Lewis Dahl and Dr.  Lot Page have both
 stated  that the infiltration of road salt  into our water supplies is
 a very  serious and urgent problem.*

 4.1.2  Other Water Resources                               i

 Examination of the literature has shown that deicing salts**-usually have
 very little effect upon large rivers and streams.  Because  :the rate of
 flow is so large,  especially during the spring thaw  when the  bulk of
 the salt is released into the river, the sodium  chloride is substan-
 tially  diluted.  Large rivers rarely show  an increase  of more than 10
 to 20 mg/1 of sodium chloride (91, 93,  108).
*  Personal Communication, June 10,  1975 and June 11,  1975 respectively.
** Primarily sodium chloride with the rest calcium chloride.
                                    20

-------
Smaller streams and brooks may be much more seriously affected depending
on their flow rate and the amount of highway runoff.  During a study
of the Irondequoit Bay Drainage Basin in Monroe County, New York, it
was observed that the principal input to the Bay, Irondequoit Creek,
reached a winter maximum of 670 mg/1 chloride.  Maximum concentrations
in ten small creeks were found to range from 260-46,000 mg/1 chloride
during the winter (73, 80).

The final destination of such streams must be examined closely in order
to determine the resultant effects.  For example, Diamond Lake in
Hennepin County, Milwaukee, Wisconsin was reported in 1970 to contain
the equivalent of 3,780 mg/1 sodium chloride  (48).  Undoubtedly in some
cases the effects on aquatic life in the receiving bodies may be serious.
It has been observed that heavy flow of salt may prevent complete mixing
and prolong stratification of the water.  Such extended stratification
can result in oxygen deprivation in its lower depths and has caused
death of organisms living in the lower depths.  Since these animals
are-an important link in the food chain, fish kills have, resulted (89,
97).  The use of road salt has led to similar but less serious damage
in Irondequoit Bay, Rochester, New York.  If salting continues at the
current level, serious damage may occur when the dissipation of salt
in the drainage basin reaches a steady state of equilibrium.  In dis-
cussing the potential effects of salt on lakes and ponds, Adams stated
that, "...it is well within the realm of possibility that the addition
of significant amounts of salt could contribute to the biological
process of aging in lakes called eutrophication." (1)

Other studies have shown that under special conditions, the entry of  road
salt into freshwater can cause mercury and other toxic heavy metals to be
released from contaminated sediments  (82).  Release  of these metals in ponds,
lakes or reservoirs that do not have a high inflow/outflow rate might
present a serious hazard to the aquatic and human life.

4.1.3  Soil

While discussion ,of damage to roadside soils may seem unnecessary in
addition to an examination of vegetation and water damage, it is indeed
an  element of the environment which is very definitely degraded by salt.
High concentrations of salt in the soil will not only lead to the death
of  existing vegetation, but in many cases will also  lead to an almost
irreversible situation in which proper drainage is seriously affected
and only a limited variety of vegetation, if any at  all, may grow in
the soil.

Sodium and calcium chloride are highly soluble in water and easily
disassociate into sodium, chloride, and calcium ions.  The chloride
ion,  having a negative charge, is repelled by the negative charges
of  clay and other organic colloids and therefore is  easily leached out
of  the soil by water passing through.  However, the  positively charged
sodium and calcium ions are attracted to the negatively charged  clay
                                      21

-------
and other colloidal soil particles  (20).  Thus, depending on the type
of soil, amount of salt applied,, and the amount of water leaching
through the soil, as a result of precipitation, a substantial percen-
tage of the sodium and calcium ions may be retained.  The high
sodium content may result in a number of undesirable soil properties,
especially loss in permeability (24, 199).  In addition the presence
of the sodium will lead to the leaching of other positively charged
ions such as potassium, calcium, and magnesium which are essential for
plant growth (20).  All of these factors can result in a poor
roadside environment for vegetation growth.  Depending on the severity
of the situation, it may take many years for the sodium to leach out
into the groundwater, rendering the soil useless to all but a few
hardy varieties of vegetation, such as high salt tolerant grasses.
Loss of vegetation has in some cases led to severe soil erosion; and1
the high soil content runoff has clogged drain sewers  (155).

As expected the highest salt content in soil is generally found near the
highway and near the ground surface.  Concentration generally decreases
with depth and distance from the road surface.   Some salt in soil has
been found as far as 30 meters from the road but usually the concentration
is significantly decreased at 7 to 18 meters from the highway.  (This
does not include situations where runoff is collected and diverted to
other locations, of course.) (24, 96, 199)  In addition, studies have
shown that roadside soil concentration of salt increases with the number
of years salt has been applied (193).  The implication of this finding
is that application of road salt has a cumulative effect on the roadside
soil.  Continued application of road salt will very likely increase the
salt concentration to the point where eventually the soil will be
highly alkali and possibly unfit for most vegetation.

Studies by F.E. Hutchinson under a cooperative program between the Maine
Agricultural Experiment Station and the Maine State Highway Commission
have shown that high rates of application of gypsum  (3 kg/squar.e .meter)
to roadside soils can lead to a reduction in sodium in the topsoil.
(Reduction of sodium in the subsoil has not yet been proved.) (195,
196, 197)  While these findings provide some encouragement> the cost
of the gypsum application must be considered.             :

4.1.4  Vegetation

Sodium chloride applied to highways to aid in ice and snow removal has a
significant effect on the decline of roadside trees and vegetation.
While drainage conditions are an important factor in determining the dis-
tance to which vegetation is affected, most damage occurs within 9 meters
of the edge of the highway.  Other factors such as drought  low soil fer-
tility, low soil permeability, air pollution from vehicle exhaust, and
mechanical injury to roots also contribute to the damage (175).   However,
in-depth studies have shown that salt in many cases is the'prime factor
leading to death of vegetation (20, 156, 157, 174).  These•studies were
based on soil samples and analysis of sodium and chloride content in
                                   22

-------An error occurred while trying to OCR this image.

-------
 Heavy salt use and the resultant damage to vegetation can lead not only
 to personal property damage and possibly some crop damage,  bub also to
 the creation of unsightly conditions along the highway,  reducing the
 property values and negating the highway beautification programs.
 Although difficult to assess, there are real costs involved in terms of
 increased highway maintenance for removal and replanting.

 4.1.5   Fish and Wildlife

 The literature contains a few reports of death of fish and  wildlife
 attributed to salt (15, 48).   While there has been a small  amount  of
 research on short-term toxic levels of salt, there is little known
 about the long-term effects of less toxic levels.   Until further
.research is carried out, it is not useful to speculate on the possible
 extent of the damage.   However,  it is probably fair to state -that  bodies
 of water which have significantly increased levels of sodium chloride
 due to road salt runoff will demonstrate noticeable changes .in their
 ecosystem.   Such changes are unlikely to be beneficial.

 4.2  DAMAGE TO MAN-MADE GOODS

 The mechanisms by which salt damages man-made goods are described in
 this section.  Claims and accounts of salt-related damage,  predomin-
 antly to bridges and automobiles, are numerous.  The literature presents
 sufficient evidence to directly link the damage to deicing salt use.
 Reports of public officials as well as professional engineers and con-
 cerned citizens leave no room for doubt as to the nature or extent
 of the damages.

 Such damage is more easily observed than is the damage to;the natural
 environment.  A sampling of some of the specific reports is presented.
 Section 5 will present an economic assessment of the damage caused by
 deicing salts.

 4.2.1  Corrosion of Motor Vehicles

 It is likely that more people have directly observed vehicular corrosion
 than any other form of salt-related damage.  The link between the
 application of salt on highways  and the corrosion of automobiles is
 well documented (see Bibliography).  This section of the report will
 discuss the corrosion  process and examine parts of the automobile
 susceptible to it.   Section 5.5 contains an economic analysis of the
 probable costs of this corrosion.

 The Corrosion Process  —

 The corrosion of steel is  an  electrochemical reaction in which iron is
 oxidized to the ferric state.  In the presence of  moisture  and atmos-
 pheric oxygen,  the  free energy of the reaction is  such that iron is
 spontaneously oxidized to  form the insoluble hydrated ferric  oxide
 (rust).   This is the typical  reaction occurring in the near neutral
 environment of auto body steel.  When acids are present, oxygen is  not
                                   24

-------
required and the iron is first oxidized td the ferrous ion.  This ion
can be further oxidized to the ferric state and react with hydroxyl
ions to form ferric oxide.  Both reactions (with water and oxygen or
with acid) can be prevented by eliminating contact between the
metal surface and any of these elements.  This is the motivation behind
such rustproofing procedures as painting and asphaltic coating of steel.
Galvanizing sheet steel protects the steel for a longer period of time
because zinc is electrochemically more active and is thus oxidized
in preference to the iron.  Dipping steel in a zinc rich paint initially
protects it by preventing moisture and oxygen from contacting the
surface; and offers further protection though preferential oxidation
of the zinc.  Unlike aluminum, an exterior layer of oxidized steel
offers no protection from further oxidation and in fact may accelerate
the corrosion process.

Because steel is not a homogenous, cyrstalline product, there are small
differences in surface composition in ordinary sheet steel which can
cause minute  electrical potentials to develop.  Further exacerbating
this  tendency is the presence  in motor  vehicles of other metals, spot
welds,  and stresses from  metal forming.   In  contrast  to the general,
overall even  oxidation  that will occur  in untreated steel  in  the
presence  of moisture and  oxygen, minute electrical potentials in the
steel itself  result in  the  potentially  more  serious pitting corrosion.
Pitting is attributed to  differential oxygen concentrations at  the
metal surface.   Those parts in contact  with  oxygen become  cathodic  with
 respect to oxygen  deficient areas.   In  cathodic regions hydroxide
 ions  are produced, while  in the anodic  regions  iron goes  into solution
 as the ferrous  ion.   It is  in the  anodic regions, which  are protected
 from oxygen by  paint, undercoating or other  layers  of steel,  where  the
 serious pitting takes place.   This has  led some experts  to question the
 wisdom of protective coatings, unless they can be so  thorough as to
 prevent any contact with moisture and oxygen.  Even totally  protective
 coatings may be subject to attack by vibration at joints.

 A number of other parameters have been shown to effect corrosion
 rates including temperature, the presence of electrolytes, and the
 removal of corrosive products from the anodic and cathodic regions.
 Chemical reactions are temperature dependent; the rate of reaction
 approximately doubles for every 10°C rise in temperature. Electrolytes
 such as salt, fertilizers and the soluble products of atmospheric
 pollution accelerate the corrosion process by facilitating electron
 transfer.  It can be inferred that autobody steel will corrode^most
 rapidly when protection  from oxygen is only partial, and when it is
 placed in a warm, humid  environment in the presence of neutral or
 acidic electrolytes.

 Experimental Evidence of Auto Corrosion  —

 A series  of  experiments  that have sought to  define the role  of deicing
 salts  in the corrosion of  automobiles was initiated  in the mid 1950s
                                    25

-------
 in response to  the unprecedented corrosion that was being  observed
 in and around headlights, wheel  wells  and  door panels on the  new  cars
 of that era.  These field tests  are  discussed below with respect  to
 the parameters  assessed.

 Atmospheric Conditions  —                                  •

 Relative humidity  has a significant  effect on the oxidation of many
 metals.  Condensation on metal surfaces will tend to occur at relative
 humidity levels far below 100% due to  impurities on the metal surface
 or in the  atmosphere.   Reports from  Switzerland, Germany and  Canada
 (206)  indicate  that when the  relative  humidity exceeds some critical
 value ranging from 60%  to 75% the*.'corrosion rate is markedly  increased.

 Increasing attention has been given  recently to the role of atmospheric
 pollutants in the  corrosion process.   Craik and Yuill  (206) found the
 atmospheric corrosion rate to be higher in the city of Winnipeg,
 Canada,  than in the surrounding  suburbs.   Atmospheric corrosion rates
 in eight different areas across  Canada were measured by Frbmm (205)
 by attaching test  metals coupons to  automobiles.  Conditions  in these
 areas ranged from  very  dry to very humid;  from coastal to  inland; and
 exhibited  a wide range  of atmospheric  pollutant concentrations.   In
 high density areas where the  atmosphere contains large concentrations
 of sulphur dioxide,  the corrosion rate is  approximately four  times
 that of  rural areas.  Corrosion  rates  are  also markedly increased
 when in  proximity  to a  large  body of salt  water.

 Deicing  Salts —

 Several  experiments  have sought  to quantify the partial effect of deicing
 salts on the  corrosion  rate of automobiles.  In the investigation by Fromtn
 (205), traffic  simulator tests performed with and without deicing salts
 indicated  that  salts and atmospheric  pollutants each increased the
 corrosion  rate by  approximately  the same amount in the Toronto area.

 In  the test sponsored by the  Research Foundation of the American
 Public Works Association (APWA)   (209), three groups of automobiles were
 driven over controlled  road sites in the Minneapolis suburbs for  three
winters.   The partial effect  of  atmospheric pollution in this region
was measured by  test coupons  attached to automobiles (where the
 combined effect  of atmospheric pollution and salting would I be measured);
 and other  coupons placed in the vicinity,  but removed from'deicing
 salts.  While the  fraction of the corrosion rate attributed to salt
varied from 15.9% for a spring exposure to 65.2% for a winter exposure,
the report concluded that a likely figure for the area was approximately
 50%.

The principal difficulties associated with using the APWA study  to pro-
ject national corrosion estimates attributable to road salting are
 (1) climatological and atmospheric variation is lacking due to testing
in only one location, and (2)  an ordinal index of severity ' (0,1,2) was
                                   26

-------
improperly used to compute a cardinal measure of percent corrosion
attributable to salt.  Additionally the use of only one make of
automobile (1968 Ford Falcons from the Kansas City production line)
may have produced biased estimates if this make and vintage is not
representative of the "typical" automobile in use.

In a related test sponsored by the National Association of Corrosion
Engineers (NACE) (207), electrical resistance probes were attached to
automobiles in 14 different cities.  The experiment was designed to
measure the partial effect of deicing salts and reached similar
conclusions to those of the APWA study.  No attempt was made to
statistically analyze the separate impacts of atmospheric pollutants,
humidity, temperature, and the use of deicing salts on the measured
corrosion rates.  Such an analysis would be highly desirable but is
not possible because of gaps in the data caused by failure of certain
probes.

In the APWA-Salt Institute test  (209), and in earlier experiments  in
Canada and Europe, various chemicals were tested  for their effectiveness
as corrosion inhibitors.  Typically the chemicals were mixed with  the
salts before application  to highways.  Corrosion  inhibitors were shown
to have very limited potential in  reducing salt induced corrosion  of
automobiles.   In addition, they posed  serious adverse environmental
consequences such  as the  health endangering  effects of hexavalent
chromium  (15).

Other Factors —

Storage of an  automobile  in a  closed,  heated and  poorly ventilated
garage during  the  winter  may exacerbate corrosion in areas where
snow,  ice, and deicing  chemicals have  been deposited.  The apparent
explanation  for this circumstance  is,  as mentioned earlier, that
chemical  reactions are  temperature dependent.

The  corrosion  rate of an  automobile is significantly affected by the
shape  and construction  of the  automobile body.  Of particular impor-
tance  are those steel surfaces accessible to moisture, oxygen and
electrolytes.   Since pockets which collect dirt and debris tend to
retain moisture long after other  surfaces have dried out, they  are
sites  of  the most  severe  corrosion.   Felt, fiber  glass, rubber  and other
materials that tend  to  retain  moisture accelerate the corrosion process
when in  contact with steel.

Areas  Affected by  Corrosion  in Vehicles —

The  safety and the economic  value of  an automobile are  adversely
 affected by  corrosion in  three main  areas: the  chassis  and box  sections,
the  braking  system and the electrical system.  The most visible
 effects  of corrosion occur in  the box sections which are made up of
 thin steel sheets  connected  by welding.   Structural weakness  caused  by
 corrosion of the  chassis  and box sections reduces the protection offered
                                    27

-------
by the automobile in an accident.  The corrosion of floor panels
eventually allows exhaust gases to enter the passenger compartment.
For  automobiles manufactured with unitized body construction, the
replacement of a corroded section frequently costs more than the value
of the car.

The  most vulnerable parts of the braking system are the hydraulic brake
lines.  These lines are quite thin and are exposed to moisture,, salt
and  other electrolytes, and oxygen.  If pitting corrosion is initiated,
perhaps because of partial protection offered by rubber mounts,. the
ultimate consequence can be serious.  The semi-permanent rusting-in-
place of items such as wheel lug nuts, spark plugs, brake drums; and
exhaust system clamps, accelerated by exposure to deicing salts, makes
work on these parts much more difficult and thus increases the costs
of repairs.  Performance of the electrical system is also adversely
affected by corrosion.  Failure of headlights and turn indicators is
a frequent consequence.

There is evidence that corrosion is initiated on the exterior of the
exhaust system as well as from the interior, and that deicing salts are
one  of the factors causing this external corrosion, in combination with
humidity and temperature.  In the snow belt, Midas Mufflers Inc. found
that non-galvanized mufflers lasted an average of 18 months and that
galvanized ones lasted 24 months.  Outside the snow belt the typical life
of a galvanized muffler is 48 to 60 months.*  The .two-fold increase in
muffler life away from the snow belt (and deicing salts) may imply a
strong role for deicing salts in the exhaust system corrosion process.

There has been a variety of 'damages reported by :K'ighwa'y engineers.
Vehicle corrosion for maintenance trucks rates high on this: list of
associated damage for which costs are incurred by the publig at large.
In Lancaster, Pa., reports one survey respondent, "The beds of all
pick-up trucks become corroded and eaten out very rapidly.  Despite
constant washing of the beds the chemicals become lodged between the
wooden bed and sides of the truck body.  In less than two years  the
sides of the truck body become eaten out."+

According to the same individual, "Another frequent repair is with
brakes and hydraulic brake lines of trucks with salters mounted on
them.  The salt becomes embedded in the brake shoe adjusting mechanism
and corrodes the surface to a point where complete dissassembly  of
the brake is necessary.  The hydraulic brake lines that are!fastened
with clips to the body for support become corroded and require frequent
replacement."$
* Per spokesmen of Midas Mufflers, Inc. and A.P. Auto Parts*

+ Lancaster, Pa., respondent to Highway Department survey.
* Ibid.
                                    28

-------
A spokesman for the New England Telephone Company indicated that rust
is a greater problem than mileage in terms of maintenance on their
fleet of 9,800 vehicles.  Despite salt preventive measures taken by the
service department — rust proofing, patching, and washing the vehicles
on a regular basis — their sedans are held for only two or three years
and their trucks for four or five years, compared to a nine year average
life expectancy for Southwestern Bell, Texas*  fleet vehicles.  These
vehicles remain in service almost a decade despite their exposure to
sea salt spray along the gulf coast and some deicing salt use for
icing conditions in the pan handle area.   This clearly illustrates
the impact of continued use of high volume chloride salt on the utility
companies maintenance costs.  Of course these increased costs of
providing service will be passed directly on to the consumer.

An unusual extension of highway department maintenance problems
related to salt use occurred in Saginaw, Michigan, where the "in-
floor radiant heating system in the main storage garage deteriorated
in approximately five years due to salt runoff from vehicles."  The
only available means to correct this difficulty was to "replace
 the heating  system with.overhead gas blowers  (at a cost of $18.5
thousand)".+

4.2.2  Damage to Highways and Highway Structures

There have been many claims of salt-related damage to highways, bridges,
 and other highway  structures.  A thorough research of the literature
 and a survey of all snow-belt state highway departments and  approximately
 100 large city highway departments have disclosed that there has been
 extensive salt-related damage to bridge decks.  By comparison, damage
 to highways  in general has been small.  There were only a very few
 reports of damage  to other highway structures.  Apparently guard
 rail deterioration can be a problem, but  frequent painting seems  to
 prevent  the  deterioration.  No cost data  could be obtained on this
 added maintenance.

 In  this  section,  the process by which bridge  deck damage occurs is
 explained.   This process has been verified by many sources.   (See
 Bridge  references  in Bibliography.)

 Damage  to Bridges  --

 Bridge  deck deterioration ranks  high among major maintenance problems
 on our  nation's highways.  The most common forms  of deterioration  are
 cracking,  scaling, and spalling.   Cracking is not  considered to be  a
 very serious problem,  although  it can lead to the  formation  of potholes.
*  Paul Le Blew, Southwestern Bell, San Antonio, Texas, in a telephone
call 6/19/75.
+  Respondent, Saginaw, Michigan, Highway Department questionnaire.
                                    29

-------
 Scaling is principally a surface phenomenon  and is  largely :eliminated
 by the use of high quality,  air-entrained  concrete  and the periodic
 application  of linseed oil.   Spalling produces cracks and potholes and
 is serious and difficult to  control.  In addition,  the supporting struc-
 ture for the bridge may be significantly damaged.

 The Nature of Cracking and Scaling,—

 In bridges,  cracking may be  caused by  (1)  shrinkage- of concrete due to
 excessive evaporation  rates  during the drying process;   (2) design features
 associated with dynamic tensions and flexing in the bridge which result
 in material fatigue;   (3) inadequate materials, especially the use of
 improper material  ratios in  mixing concrete;   (4) faulty construction
 techniques;  and  (5) various environmental factors  such as weather, mois-
 ture,  and the loads carried.  With proper  attention to design, materials,
 and construction,  cracking may largely be  controlled.  Scaling is a surface
 phenomenon that can be caused by freeze-thaw action in the :absence of
 deicing salts.  Scaling has  also been observed in salt contaminated con-
 crete surfaces not subject to freeze-thaw  action, such as the underside
 of the Biscayne Bay Bridge and Key West bridges in  Florida.  Scaling is
 most severe when concrete is subject to freeze-thaw cycles in the presence
 of saline contamination.   (226).

 The process of drying  ordinary concrete produces small capillary cavities.
 When water saturates these cavities in the concrete and is frozen, the
 freezing action alone  can cause scaling as the volume of water in the cap-
 illaries expands by about 9%.  This expansion frequently causes; a flaking
 or scaling of the  thin layer of concrete over the cavities.

 Air-entrained concrete in part prevents this scaling.  Air entrainment
 is produced by incorporating large air bubbles in the concrete as it is
 produced.  Since water preferentially seeks  smaller capillaries, these
 large cavities  remain  relatively dry in water saturated concrete and pro-
 vide a point  for pressure relief when freezing temperatures are reached.
 In a systematic test of  110  different coatings (235, 244), linseed oil
 treatments were found  to be  one of the most effective and economic means
 of preventing  scaling  when applied to air  entrained concrete.

 Salts provide more moisture  on the surface of the'pavement by lowering
 the  freezing point of water.   They also create additional freezing below
 the pavement  surface.  This  latter phenomenon, known as thermal shock,
 occurs when heat is absorbed  from the pavement as ice goes into solution.

 Spalling —

 Spalling is the process by which the pressure from rusting reinforcing
bars  cracks a concrete cover.  (See Figure 8).  The preponderant amount
of deterioration from  spalling is associated with the use of deicing
 salts and ocean salt sprays.   The corrosion process of reinforcing rods,
which deicing salts accelerate, creates a pressure of about- 280 kg/sq, cm.
 (4,000 Ibs/sq. in.) aasily sufficient to crack the concrete cover over
the rods  (231).  Inspections  of bridge structures have revealed that
                                    30

-------
Figure 8.  Example of Deck Spall on underside of West Side Highway
         (Photograph courtesy of Department of Highways, New York City)
                                 31

-------
transverse cracks in  concrete may result from freezing and thawing in
the presence of  saline  contamination.  Transverse cracking in freshly
poured concrete  is  frequently observed as the deck moves under the weight
of the concrete, and  as the concrete slowly settles around the reinforcing
steel.  An effective  means of closing these incipient transverse cracks is
the revibration  of  the  concrete several hours after it is poured  (226).
Transverse cracks may also be caused by too shallow a concrete cover over
the rods and by  shrinkage during the drying and curing of the concrete.
Such cracks provide access to moisture which then can attack the underlying
steel.  The rust process is greatly accelerated by the presence of salts
and air along with  the  moisture.  Experiments by Herman  (212) indicate
that pH reduction may be a contributing factor- in steel corrosion.  Rein-
forcing steel is typically protected in chloride free concrete because of
the high pH of the  soluble calcium hydroxide originally present in the
cemet.  This high pH  induces the formation of a protective coating of
ferric oxide on  the surface of the steel.

Because of the porous'nature of the concrete, rusting of reinforcing
steel can take place  without preliminary cracking since saline solutions
will slowly penetrate the concrete cover.  It has been found that the
chloride ion concentration around the reinforcing steel is reduced by
approximately one half  for each additional inch of concrete cover (236).

Age of concrete before  exposure to salt solutions is an important
factor in inhibiting  corrosion.  It has been observed that bridges
built before the 1940s, when salts were first used extensively for
deicing, have in many instances survived better than newer bridges.
This may be attributed  to the substantial length of time required for
concrete to properly  cure, though it may also be partially explained
by a process of  "natural selection" and examples of superior:workman-
ship and materials.

Advanced cases of spalling on a bridge deck are easily detected by the
presence of large potholes on the surface.  These cracks and;holes can
cause discomfort and  reduce the safety of passing motorists and cause
damages to automobile shock absorbers, bearings, and ball joints.  In
infrequent instances, reinforcing steel is corroded to such an extent
that a bridge is incapable of carrying its designated load.  :Less
advanced cases of corrosion can be detected by a variety of techniques
including electrical  potential measurement to pinpoint the corrosion
site  (236).

Repair Techniques —

Accepted methods for repairing bridge deck spalling involve temporary
patching of holes, partial restoration of the deck or replacement of
the entire deck cover.  Patching of holes without removal of cracked and
salt contaminated concrete is an unsightly and usually only a temporary
means of repairing spalled sections.   A large fraction of patches made
in a freeze-thaw environment will fail in less than a year.   Many of
the potholes form during the winter months,  a time when patching is
                                     32

-------
more difficult and driving hazards greater than during the summer.  Main-
tenance patching, even when properly done, may be less desirable than
other methods of repairing damaged bridges.  Although highway departments
view the dollar outlay for maintenance patching as minimal, the full social
costs including safety hazards, damages to vehicle suspensions, and traffic
delays must be considered.

Partial restoration involves devising more permanent patches, with esti-
mated life of about 15 years, by removing the concrete surrounding the
corrosion site.  The. resulting hole is patched with Portland cement con-
crete, or epoxy concrete when the speed of setting is important to minimize
traffic delays.  The surface is sealed and an overlay of asphalt concrete
is applied.  The practice of sealing the surface of partial restorations
also has been questioned by Kliethermes who feels that such deck covers
may accelerate corrosion in previously undamaged sections of the deck (230).

Unfortunately removal of active corrosion regions usually is not sufficient
to halt the corroding process, and other sections may begin to spall soon
after the repair is completed.  Formerly passive sites can quickly switch
to being active sites as electrons flow to the sections having the greatest
positive potential in the deck.

Replacement of an entire bridge deck is an expensive process with repair
costs reported between $400,000 and $1,200,000 for large bridges, and is
normally justified only when the spalling damage is extensive.  Most bridges
do not remain part of the highway system for a period as long as 50 years.
Partial restoration seems to be more desirable when the time value of money
is considered, since expenditures 15 to 30 years from now should hot get
equal weight in a comparison with outlays today for replacement.  Until
complete replacement is possible, Kliethermes  (203) advocates temporary cold
mix bituminous patches on bridges which exhibit active corrosion on 50%
to 100% of the deck.  For decks where 20% to 60% of the structure contains
corrosion sites, concrete removal and patching of chloride contaminated
areas is recommended.  For bridges containing active cells in 25% or less
of the deck, he suggests removal of chloride contaminated sections followed
by placement of a waterproof membrane and an asphaltic, concrete wearing
course.  These recommendations are based primarily on economic considera-
tions .

 Deck  seals  are commonly  used in  replacement  of existing decks  and on new
 decks.   In Europe, the  use of waterproof membranes, designed  to prevent
 the  intrusion of moisture and salts  to the reinforcing steel has
 gained widespread  acceptance for new construction and for the  repair
 of existing bridges (233).   Many different materials  have been used as
 membranes  including:  copper sheeting, butyl  rubber sheeting, bitumen-
 aluminum sheeting,  bituminous felt,  and  adhesive coated polypropolene
 fabric.   Dissatisfaction with these  methods  has led  to experimentation
 with epoxy resins  and polyurethanes.   In the United  States prior  to
 1970, membranes were frequently  produced on  site by  applying several
 coats of a coal tar pitch to the concrete surface, and sandwiching  a
 layer of glass fabric between coats  if reinforcing is desired.  The
                                     33

-------
ability of the membrane to reseal itself in periods of warm weather
significantly adds to its waterproof qualities  (238).  In Europe
and in the United States, preformed sheet type membranes are more commonly
used now.  Over both types of membrane an asphalt wearing course is
applied.                                                    '

Experience with membranes indicates that they frequently do not perform
as well as anticipated.  Membranes are hand placed and  as such are
subject to poor workman performance.  Additionally, the application
of hot asphalt may melt the membrane.  In situations where the grade
exceeds 4% or there are centripetal forces from curves and braking,
the asphalt overlay tends to slide across the membrane.  This limits
the situations where membranes may be successfully utilized.  The
typical membrane leaks after a few years, though still offering some
protection to the underlying steel.

A number of other procedures to inhibit corrosion of reinforcing steel
have been tried, including various coatings applied to the steel before
placement.  Although many different coatings - including asphalt epoxy,
epoxy, nickel, copper and zinc all have been used in experiments, the
epoxy coating appears to have the greatest promise  (234).  Epoxy coated
steel is approximately twice as expensive to place as ordinary steel,
and results in an increase in total cost comparable to the waterproof
membrane.  Special tests have been designed to insure that the coated
reinforcing rods will not (1) allow passage of chloride ions to the
steel, (2) suffer cracks in the coating when bent at an angle of 120°,
or (3) abrade during placement.

Cathodic protection is an experimental method of preventing the destruc-
tive flow of electrons necessary for the oxidation of reinforcing steel. .
It has been shown to be capable of halting corrosion in decks already
thoroughly contaminated with chlorides.  In a paper delivered at the 1975
meetings of the Transportation Research Board, Harold Fromm, of the Ontario
Highway Department, described the results of continuing experiments with
cathodic protection.  Following upon Stratfull's pioneering work, bridges
were protected by placing graphite anodes in the deck, covering them with
asphalt concrete, and applying approximately 3.23 milliamps of current per
square meter.  Preparation of the deck in this manner took approximately
two days and resulted in minimal traffic disruption.  Power requirements
for the entire bridge are approximately 1.5 watts per hour, and were so low
that the power company considered it-not worth installing an electric meter.
Actual costs of cathodic protection were $96.82 and $39.37 per square meter
on the first two bridges, but were expected to fall to only $9.25 on the
fourth installation.  The general feeling is that cathodic protection is
best applied to bridge decks that are still in sound condition, and that
badly deteriorated decks are best replaced.

Experimentation with the composition of concrete dates back to at least
the 1940s.  Since that time, a latex modified concrete (Dow SM--100) has been
marketed for patching bridge decks.  The repairs have performed well and
the Federal Highway Administration is now using this concrete for overlay-
ment on some bridges.  In the early 1960s, silicones were investigated as
                                     34

-------
an admixture to prevent scaling (220).  The FHWA is currently studying
the feasibility of impregnating concrete with polymers (212).  In this
process, which is being field tested by the U.S. Bureau of Reclamation
in Denver, dry heat is first applied to a deck.  Next, approximately
1/2 cm of dry sand is spread and saturated with liquid monomers (typically '
lucite or methyl methacylate).  The sand appears to significantly .aid
penetration, which is carried to a depth of about 2 1/2 cm, and leads to
uniformity in application rates on uneven surfaces.*  Finally the monomer
is polymerized in situ with heat.  Polymer impregnated concrete has many
advantages over ordinary concrete.  It is impermeable to chlorides, improves
abrasion resistance by providing a harder surface, and has greater freeze-
thaw resistance.  It is unknown at this time how resistant the new concrete
will be to cracking; cracks could prove serious if they allow intrusion of
chlorides to the reinforcing steel.  Costs of this method are uncertain
primarily because they involve the consumption of liquid monomers far in
excess of current production capacity.  The ultimate cost may be comparable
to present waterproof membranes.+

Another promising modification of concrete is the incorporation of small
pieces of wax in the mix as it is poured.  After the concrete has cured,
heat is applied, melting the wax and  sealing the cappillaries.  Initially
beeswax was used but because of greater availability and lower cost, mon-
tan wax, and later a mixture of parafin and montan wax, was used.  In field
tests to date, this treatment appears to produce a concrete that is imper-
vious to attack by moisture and salt  solutions.

Damage  to the West Side Highway  in New York City

While it  has been an  accepted fact that  deicing salts  can  cause
serious damage  to bridges  and highway structures,  and while  there have
been numerous  reports and  research on the  matter,  by  far the most
devastating damage  that has  occurred is  the general deterioration of
the West  Side Highway in New York City  (221,222,223,224).  On
December  15,  1973,  the northbound roadway  between Little West 12th
Street  and  Gansewoort Street collapsed.   (See Figure  9).   At that
time the  Transportation Administration of  New York closed  the section
of the  highway between the Battery and  46th  Street for an  indefinite
period.  Immediately thereafter the  Division of Bridge Design of the
 *  Lehigh University is currently under contract to the Highway Research
 Board to investigate the feasibility of impregnating concrete to the  depth
 of the reinforcing rods.

 +  According to Hay (225),  polymer impregnated concrete contains by weight
 approximately 6% polymer,  or about 3.6 kg of polymer per square meter of
 surface to the depth of 2 1/2 cm.  Current costs of Lucite range from $.66
 to $.88 per pound indicating a direct cost of monomer of $2.37 to $3.27
 per square meter.  The remaining costs would be attributable to heating and
 labor.
                                     35

-------
                                                   "™' •.'•'.- •-"?• -''""-"• ''i1"
      Figure 9. Collapse of West Side Highway at Ganesvoort Street on 12/15/73
              (New York Times Photograph)
Department of Highways performed a preliminary survey between the
Battery and  59th  Street and confirmed the extreme structural  deter-
ioration of  the connections between longitudinal girders  and  transverse
floorbeams.   (See Figure 10).

There had been no inspection of this city-built highway for 40 years.
Following the 1967  collapse of the Siver Bridge in West Virginia,  from
I-Bar failure related to stress, National Bridge Inspection Standards
                                   36

-------
       Figure 10. Typical Stringer Web Deterioration on West Side Highway Structure
                (Photograph courtesy of Department of Highways,, New York City)
were instituted in 1968.  For the city to determine the true  condition  of
the West Side Highway, however, the Transportation Administration  contracted
Hardesty and Hanover, Consulting Engineers, to conduct a complete  examin-
ation.  Their analysis, conducted from July 9 to November 14, 1974, resulted
in four substantive volumes, the last dated May 30, 1975.  The following
quotes are taken in-context from the most recent report:

     "The deterioration of. the West Side Highway has been a continuous
     problem.  As early as the mid-fifties public officials had antici-
     pated its early demise.  The use of salt to remove ice,  combined
     with heavy traffic, has caused disintegration of large sections of
     the roadway.  On several occasions, prior to the December 15, 1973
     failure and closing, portions of the roadway slab have fallen into
     West Street.  The asphalt overlays, which replaced the original
     granite block wearing course, are also in poor condition with
     holes and surface cracking.  The damaged concrete has been tem-
     porarily repaired by covering the holes with steel-plates supported
     by the steel superstructures which, in certain areas, has been sub-
     jected to extensive corrosion."  (224, p. 21)

     "Our inspection between the Brooklyn Battery Tunnel and midtown
     reveal that serious conditions and deterioration exist at many loca-
     tions on the West Side Highway; therefore, the entire roadway south
     of 46th Street should remain closed until a decision is made whether
     to demolish the structure or to proceed with repair and rehabilitation."
                                     37

-------
     "The deterioration is a direct result of water and waterborne
     salt leaking through the expansion joints and the concrete
     deck.  Water passing through the wearing course follows the slope
     of the concrete deck to the longitudinal girders where it leaks
     through cracks or through the joint between the deck and the
     girder web.  Depending on the cross slope either the exterior or
     the interior floorbeams are affected."  (224, p. 25)

The report concludes that although restoration of the highway is
feasible, the cost of the work is almost prohibitive.  The chief
engineer* for the New York City Department of Highways estimates that
it will cost $58 million to perform a partial rehabilitation ;of the
West Side Highway from the Battery to 72nd Street.  Hardesty and
Hanover suggest that restricted rehabilitation for maintenance of the
existing structure including "new deck, median barrier, lighting,
painting, and steel repairs would cost about $66 million in 1976."  (224)
A complete rehabilitation including some updating or modernizing would
entail $88 million according to a New York City Highway Department
representative.  The fourth and most expensive serious alternative^
presently before the city council is a proposal to demolish the existing
elevated highway and build a new interstate highway to be called the West-
way.

Not surprisingly, the consultants conclude, in part, "Use of salt for
deicing should be minimized.  Other methods and materials for maintaining
traffic during ice and snow conditions should be considered.1!   (224, p. 35)
The chief  engineer* affirms that deterioration of the West Side Highway
structure was accelerated by the brine of dissolved rock salts compounded
by the problem of poor drainage.

While the cost of the repairs to the West Side Highway may not be represen-
tative of typical bridge damage, there are other examples of costly salt
induced deterioration.  Recently it was reported that four Washington, D. C.
bridges had become dangerous to traffic because salt had caused extensive
corrosion of the reinforcing steel.  The cost of the repairs is i$11.7
million.  (330)

Pavements —

With  proper attention  to  design, materials and  construction,;cracking
can largely be  controlled.  Concrete pavements  are  less vulnerable  to
spalling than are bridge  deck pavements due  to  a number of  factors:
 (1) bridge  decks are subject to greater flexing stresses;   (2)  rein-
forcing  steel is not as common in highway  construction but  where  it
exists the  concrete cover is.generally twice as thick as the.2  inches
normally used in bridge deck construction;  (3)  transit mix  concrete,
which is more variable because of  the use  of several mixers, is usually
used  to  cast bridge decks;  central mix concrete is  normally used  for
highways; and  (4) other factors including  reduced homogeneity resulting
 *  Personal Correspondence with the Chief Engineer, Division of Bridge
    Design,  Department of Highways, New York City.
                                      38

-------
from extensive hand finishing, and increased surface exposure sub-
jecting parts of the bridge structure to environmental stresses such
as freeze-thaw action that the underside of pavements are protected
from.  For these reasons, salt related damage to highways is far less
frequent than damage to bridge decks.

4.2.3  Utilities

There have been a number of reports of corrosion damage to underground
water mains, telephone cables and electric lines (15,26) resulting
from the use of deicing salts.  There have also been reports of damage
to above ground electrical insulators from airborne roadsalt (318).
The evidence at the time of these reports did not clearly show that
road salts were to blame.  That link has now been clearly established
by two very thorough analyses.

Telephone and Electric Power Transmission Lines —

The first study was carried out between February and June of 1974 under
the direction of Joseph D. Block, Executive Vice President of Consoli-
dated Edison Company of New York (246).  Mr. Block took on the study ,
in response to the statement that there is "little data available either
to substantiate or to disprove these reports" of corrosion to under-
ground power transmission lines in the 1972 report, Deicing Salts and
the Environment produced by the Habitat School of Environment and the
Massachusetts and National Audubon Society (26).  On June 3, 1974,
after extensive analysis of corrosion damage and salt use in all
boroughs of New York City between 1970 and 1974, Mr. Block wrote
the following to the Habitat School of Environment:

     "Con Edison operates in New York City the largest system of
     underground electric facilities in the world.   We had a unique
     opportunity in the past two years to assess the damage to this
     system by reason of the use of salt on the City streets.  The
     winter of 1972-73 was quite mild and there was very little
     snow.  The City used only about 20,000 tons of salt during the
     winter and I suspect most of this was used on bridges and
     bridge approaches, etc., which are more apt to be subject to
     rain freezing on road surfaces than are average City streets.

     During the past winter there were two storms of serious
     proportions when the streets were heavily salted.  One of these
     storms was in December, the other was in January.  The City
     used approximately 120,000 tons of salt this past winter or
     100,000 tons more than the winter before.

     The effect of this salt on our.electrical system becomes evident
     almost immediately after it is used and continues for two to three
     months as thawing snow and rainstorms .wash the resultant brine
     through our subway systems.   Our secondary cables (generally
     rubber insulated and operating at 120 volts) develop short
                                   39

-------
     circuits and catch fire.   There were approximately 1,400 more
     manhole fires this past winter than the previous winter.  These
     additional manhole fires  required extensive repairs and the
     replacement of almost 1,000 sections of secondary  cable
     at a cost in excess of $4,000,000.

     The effect of the salt on our primary feeders  (cables  operating
     at 13,000 and 27,000 volts)  develops more slowly because of  the
     heavier insulation and better coverings than are used  on
     secondary cables.  For the first four months of 1974 we had
     125 more failures on our  primary feeders than  we did during
     the corresponding period  of 1973.  Replacement of  cable
     associated with these failures cost Con Edison approximately
     $250,000.                                           ;

     We know that the brine has corrosive action on our underground
     transformers, switches and other equipment. It also has,, as
     mentioned in your report, a deleterious effect on  the  concrete
     in the manholes and ducts used in our subway systems.   Because
     these effects do not become apparent for several years, we
     cannot place a price on the deterioration caused this  past
     winter.

     Altogether, it is safe to estimate that the salt  spread on
     the streets of New York City resulted in additional expendi-
     tures by Con Edison in excess of $5,000,000 during the winter
     of 1973-74  (245)."

No estimate of the cost to consumers as a result of power outages has
been made.  Based on the data collected by Mr. Block,  several hundred
power outages during the severe winter months can be attributed
to road salt use.  The cost of such extensive power losses  is very
significant in terms of inconvenience, lost production time, and lost
personal time.

It is likely that the costs incurred by Consolidated Edison are  far
larger than those incurred by any other municipal electric company.
Very likely many other instances of electrical damage  that have not
been so well documented and analyzed will be found to  be salt related.
Mr. Block's analysis will hopefully pave the way for other large
utility suppliers (and users)  to document and to investigate their own
reports of salt-related damage more thoroughly.          ;

As explained at the beginning of Section 4, it has been shown that
deicing salts enter into the atmosphere and are carried farther from
the initial point of dispersal  (highways) than occurs  from splash and
runoff.  In general, air pollutants  (participate and gaseous)  can
cause a variety of problems in the operation of electrical apparatus.
The buildup of pollutant films on the contacts of electrical connectors
hampers the flow of electrical current and thus impairs operation.
Particulate matter deposited on the contacts can also  prevent the
connector from closing completely and again the current flow is impeded.
                                   40

-------
In a paper on the influence of air pollutants on electrical connectors,
the economic importance of air pollutant problems is- discussed  (317).
The paper points out that connector miniaturization was being limited
by the difficulty in maintaining clean surfaces due to air pollution.
In addition, any estimate of the economic losses due to air pollutants
probably do not include the factor of expensive chemically resistant
materials, such as gold, being required in place of cheaper materials
which would not be as resistant to air pollutants.

A very serious problem in the transmission of electrical energy is the
contaminant buildup on insulator surfaces.  The problem is not unique
to salt particles but sea salt is one of the most conspicuous offenders.
One survey  (318) specifically noted road salt as the cause of some power
outages.

The reliable and uninterrupted operation of modern power systems depends
on insulation which must not deteriorate or allow disturbances,
flashovers,  and/or line outages.  The deterioration and flashovers
that do occur are mainly the result of air-borne deposits from natural
(sea salt),as well as man-made (generally industrial) sources including
road salt.

The accumulation of pollutant layers on insulators is a complicated
process depending on electrostatic, gravitational, and wind forces and
influenced by insulator shapes, the surface conditions, corona dis-
charge, and rainfall (319).  Dry deposits usually do not lead to dis-
turbances such as flashovers.  Natural processes such as high relative
humidity, fog, dew, frost, and rainfall cause the pollutant layer to
become moist  (especially when_ the__depc)sits _are hygroscopic as are salt
layers).  These moist layers were reported in 1966 to be the second
major cause of line outages  (320).

The processes leading to pollution flashover on electrical insulators
are as follows.  When the insulator surface becomes moist, current
flows across the surface and the resistive heating leads to the formation
of dry bands.  Flashovers occur if one of the discharges across the dry
bands propagates across the entire wet surface  (320).

That electrical insulator contamination is a serious problem is evident
from the rather large number of papers on the subject in the IEEE
Transactions on Power Apparatus and Systems.  An incomplete survey of
the literature noted over 25 papers on the subject since 1969.

In 1971, the results of a survey of the problem of insulator contamination
in the U.S. and Canada were published  (318).  A questionnaire had been
sent to 90  utilities and 59 responded with 309 case histories of
transmission line outages.  Each case may contain a great number of
flashovers  on different insulators and numerous outages.  Determination
of cause was made by the utility company engineers.  Road salt was
most often  a source of outage in fog conditions.  Although this survey
found only  20 of the 473 outages were attributed to road salt,  from
other information gathered since 1971 it is likely that the true extent
                                   41

-------
of salt as a causative factor has been understated.  Since deicing salts
appear to be widely dispersed throughout northern U.S. urban areas in
the winter and spring months, it appears that there are a ^number of
variables  (proximity of power lines along high speed highway, amount of
salt used, type of insulator, etc.) that make power failures caused by
deicing salts more common in certain areas.  The resulting frequency
of outages in a few areas means an even higher cost of inconvenience
to the users affected.

Underground Pipe Corrosion —                             ,

Soil moisture is a necessary condition for the external corrosion of gas
and water mains to occur.  The corrosion process is enhanced by a number
of additional factors, one of which is the presence of sodium and
chloride ions from dissolved deicing salts.  Natural soil resistance to
electrolyte migration is decreased by salt in solution,  The electro-
magnetic corrosion process discussed in Section 4.2.1 is similar in the
case of underground pipe corrosion.  Decreased electrical resistance of
the soil allows the electromagnetic field set up between anode and
cathode to expand, and thus charged ions can travel greater distances
through the soil and the corrosion rate increases.  (245)

Summary —

The continued use of chloride salts in winter months will affect
utility companies' equipment, through direct corrosion where brine
contacts metal and concrete surfaces and through changes in electrical
insulation caused by airborne particulate salt debris.  When these
damages are allowed to continue unabated, . we will find ourselves
absorbing social costs in inconvenience, interruption of service,
exposure to increased chances of electrical fire or gas or water main
leakages, in addition to more out of pocket costs as the utilities
pass on repair costs to the consumer.  These costs are more fully
detailed in Section 5.

4.2.4  Industrial Production

The impact of sodium chloride in water used for industrial production
has received mention in the literature.  The maximum allowable levels
of chlorides for some of those industries are as follows:  Carbonated
beverages, food equipment washing and paper manufacturing (Kraft) - 200
to 250 mg/1; steel manufacturing - 175 mg/1; textiles, brewing and
paper manufacturing (soda and sulfate pulp) - 60 to 100 mg/1; dairy
processing, photography and sugar production - 20 to 30 mg/1 (15).
However, there is little mention in the literature of actual cases
in which there were costs incurred by industries because of concentrations
above these levels.  One industrial user in Peoria, Illinois was
forced to switch to city water because of salt contamination of its
private well (126).                                       :
                                   42

-------
                                SECTION .5

                     THE COST OP SALT-RELATED DAMAGE
5.1
METHODOLOGY
The evidence summarized in the preceding section suggests strongly that
deicing salts may and do cause damages that frequently are not taken into
consideration by those responsible for winter highway maintenance.  Part
of the problem lies in the fact that — while the possibility of these
damages is generally known — their likely extent and incidence are only
vaguely perceived,  in order to improve the decision making process
relating to the intensity and pattern of salt application, it is necessary
to provide policymakers with the means to evaluate the total costs of
salt use.  Unfortunately, most of the research that has been conducted
on the potential damages of deicing salts has been more of a case study
nature.  This orientation has led to a situation in which research fin-
dings are interesting, but often irrelevant to or useless for decision
making, at the local or state level.

The present study examines the available evidence for its potential to
yield some indication of the likely total costs of salt use.  It is
clear that there is a critical constraint:' the basic orientation of past
research.  It is difficult, if not impossible, to infuse decision rele-
vance into research that was never intended to be designed to yield infor-
mation  for policymakers.  The method in this  study has been to clarify
prior constraints, to approach the problem of cost determination and
estimation from a comprehensive framework, to assess the usefulness of
available research against this framework, and finally to use the  (often
extremely sparse) empirical evidence to derive some indicators of the
potential range or approximate order of magnitude of costs for various
damage  categories.

Figure  11 sketches the broad framework describing the ways in which the
application of road salts generates direct and indirect costs to indivi-
duals and society.  Basically, direct costs are required expenditures by
either  individuals or government as a representative of society; indirect
costs denote losses in welfare which may affect members of society indi-
vidually or collectively.  The application of deicing salts introduces
into the environment a foreign substance which changes characteristics of
natural or man-made resources directly or indirectly  (by affecting the
environmental conditions determining their survival or life expectancy)
in a way that reduces their usefulness.  These reductions in usefulness
can be  related, at least at a conceptual level, to dollar costs which
                                    43

-------
                                                                    co  to
                                                                    S-)  0)
                                                                    O  3
                                                                    4J  r-l
                                                                    o  td
                                                                    rd  >
                                                                    P>4
                                                                        H
                                                                    4J  td
                                                                    CD  -H
                                                                      A
         fl
         ro
            C  M-i  3     id   >
4J   O
 OJ    •
        to en
ft  a)
                  U
              0)
             4J   C
              mo
              M  -H
                i-q
                                                                               o
                                                                                                   -H
                                  O
                                                                                                                 4-1  0)
•H  4J     a  to
 M   td     a>   a)
Q  S    »!  ffi
                                                                                                                 U
                            Q)  (1)
                            dn  4J  co
                            M  td  a)
                            td  iS  -H
                            ^3      H
                            U  O  Ot
                            CO  4J  a
                            •H  fl  p
                            O  -H  W
                                                                                             fl  0)
                                                                                         W  O
                                                                                         -P  Id  U
                                                                                         O  4J  p
                                                                                         td  -H  H
                                                                                         fr  ft 4J
                                                                                             •H  W
                                                                                         M  O
                                                                                         0)  (1)  H
                                                                                         ,q  M  -H
                                                                                         •P  PL)  O
                                                                                         O  ^  CO
                                                                                                            U
                                                                                                                               en
                                                                   4J   id
                                                                   H   O
                                                                    id  -H
                                                                   CO  H
                                                               44

-------
describe the damages in terms of a common denominator.   These costs
(estimated or imputed)  are an expression of the value of the "lost use-
fulness" of the respective resource, or the cost of restoring that resource
to its full usefulness.                    :

The main problem in the application of this framework to the actual estima-
tion  of costs is the nature of the relationships between damages and
salt application.  The damages resulting from the introduction of salt
into the environment are the result of complex processes.  Generally,
numerous factors other than salt must be taken into consideration in
analyzing the. relationships between salt use and any suspected damages.
Present knowledge of .the interaction of these factors is limited.  In
addition, the processes also depend on the timing of certain phenomena.
For example, in many instances, the damages associated with salt brine
runoff from the highways to vegetation or water supplies depend on pre-
cipitation  patterns.   Since precipitation fluctuates randomly over the
year, it is entirely possible  that the same amount of salt applied in
two winters produces completely different effects as the result of dif-
ferences in precipitation patterns, all other things being the same.
Moreover, the  amounts  of salt  applied tend to vary considerably over time
in response to differences  in  the incidence of snow and ice on highways.
All of  these elements  interact to produce considerable  uncertaintly  in the
known relationships between damages and salt application.  This uncertainty
impedes  the development of  a micro-analytical model which translates the
relationships  shown in Figure  11  into functional  and quantifiable expres-
sions.

Part  of this problem could  be  overcome by treating the  uncertainty in
the  functional relationships between  deicing salt use and associated
damages through a probabilistic approach.   This  approach can be  sketched
 schematically  in a form of  the following expression:
        Cost =  Probability of Damage per Unit of Resource Exposed  X

                Population (Number of Units of that Resource)  at Risk  X

                Cost per Unit of Damage


 The resource in question may be water supplies, automobiles,  underground
 cables, or any of the other elements that have been identified as being
 adversely affected by deicing salts.

 The formal presentation of the probabilistic approach to deal with un-
 certainties identifies the data required for its implementation.  The
 most important data element is the determination of the probability of
 damage for a given resource exposed to the effects of deicing salts.
 The estimation of these probabilities requires a considerable amount of
                                     45

-------
data, which allow for the isolation of the net effects of deicing salts
either tinder controlled  conditions, or through multivariate analysis
which can account for other relevant factors.  In a controlled situation,
experimental data have to be sufficient to describe some form of dosage-
response relationship, while non-experimental data have to be obtained
through such methods as  epidemiological studies.  For generalization,
the latter requires a sufficient sample of the population at!risk (which
may be quite small, depending on the problem).  The non-experimental
approach therefore implies that population-at-risk figures are already
available for the selection of the sample used in estimating1the damage
probabilities.                                              ,

Data on the population at risk are needed regardless of the way in which
damage probabilities were derived to estimate the total (expected) inci-
dence of damages.  This  figure can then be multiplied by some equivalent
of the cost per unit of  damage.

The data requirements and analytical steps can best be illustrated .by means
of an example.  In order to compute the costs of salt-related damages to
roadside vegetation, primarily trees, the probability of damage could be
defined as the probability of death for a given amount of sodium accumul-
ation in the soil.  (Assume for simplicity that death is the only rele-
vant damage category, which abstracts from a more continuous spectrum of
damages).  For different kinds of trees, these probabilities;may have
been established through controlled experiments.  Available studies on
sodium concentrations in soils at different distances from the highways
that can be attributed to deicing salts could then be used to define
and enumerate the population at risk (e.g., all trees within a 9 meter band
along "bare-pavement" highways.)  Multiplying the probability of death
by the number of trees exposed to the risk would then yield the expected
number of tree deaths attributable to the use of deicing salts.  Unit
costs per dead tree, finally, could be derived from available estimates
of the value of shade trees.                                i

In this particular example, the only information item that is available —
although with certain qualifications — is the unit cost.  Actual experi-
ments, for example those reported in "Salt Damage to Trees and Shrubs"
(168), have tended to yield less than conclusive evidence on the damage
probabilities.   However, more important is the absence of data (any data)
on the population at risk.  Trees along highways that are candidates for
deicing salt application simply have not been counted.  Similar data gaps
exist with respect to other natural or man-made resources that are
affected by salt-related damages.

In the absence of any data required to implement a more comprehensive
approach, ad hoc methods have been used to take advantage of certain
pieces of information that give some impression of the magnitude of the
problem.  This step had  to be taken in a number of damage categories
discussed below.
                                    46

-------
The analysis comes closest to the ideal approach with respect to damages
to automobiles, where multivariate analysis is used to determine the
incidence of salt-related damage, motor vehicle registrations provide
reliable data on the total population at risk, and car prices can be
used to determine the unit cost of salt-related damage.  It is interesting
to note that this method yielded the highest cost estimate of all cate-
gories examined.
                                    47

-------
5.2
       COSTS OF WATER SUPPLY CONTAMINATION
Water supplies have been and continue to be contaminated by the runoff
of deicing salts from highways.  The degree to which salt applied to
the road surface infiltrates water supplies in the form of sodium and
chloride ions may vary in response to factors such as soil consistency,
distance, topography and climatic conditions.*  But the evidence sum-
marized in Section 4.1.1 is sufficient to demonstrate that; the use of
deicing salts has led to serious problems in assuring the supply of
high-quality water in many portions of the snowbelt region.  The pre-
sent section complements this summary of the technical evidence by
examining the magnitude of damages to water supplies, primarily drinking
water, in economic and social terms.

The evaluation of the total social costs of water contamination as a
result of deicing salts faces a number of conceptual and empirical ob-
stacles.  The very nature of the costs incurred by government and
individuals as a result of salt contamination of drinking water supplies
hampers their enumeration and evaluation.  In contrast to damages to
physical structures, such as highway bridge decks or automobiles, which
require scarce resources for any remedial action, it is possible that
the contamination of water supplies may be mitigated as a consequence
of natural processes (such as precipitation) .  Empirical data show
considerable fluctuations of sodium and chloride levels around critical
pattern.
                                                          The occur-
values. + These fluctuations exhibit a random
rence of acute contamination problems (sodium or chloride concentrations
exceeding some criterion level) therefore can be predicted only as a
probable event.  This problem can be illustrated by Figure ; 12 which
shows chloride concentrations in surface waters in Rhode Island (291) .
If 60 mg/1 are regarded as a critical level
                                                a  (crude) probability
estimate for the East Providence case to exceed this level in any given
year would be 40%, since the threshold was crossed twice in five years.
In addition to the occurrence , the extent of contamination - and its dura-
tion are also subject to random factors.

These characteristics influence the behavior of any direct or indirect
costs over time.  Since these costs arise in response to the occurrence
and extent of any contamination, neither , their occurrence nor their
*   The discussion here focuses on groundwater contamination, since
runoff into surface water constitutes different problems, at least in
standing water bodies.  In flowing surface water, salt concentrations
rarely reach  significant levels.

+   These random fluctuations occur against a steady, and often acceler-
ated upward trend in  the sodium and chloride levels of drihking water
supplies.

*   The chloride level at which the sodium content exceeds 20 mg/1 with
near certainty
                                    48

-------
Chloride
mg/1












80-
70-

60-


50-
40-

30-

on_



j
ii
* •
11
* »
i i.
i \
/ *"»
/ *
- i V
\ x>-
         Legend













w
i >•«
/ J
t
i
i
i
\
i
i
t
t
i
i
t
1 A
\ /M
A\'
/'?
' \/
i
«
i
1
i
i







/

                      1     i      l      i      i
               50    '55   '60   '65    *70   '75
	  CUMBERLAND HILL

	  EAST PROVIDENCE

•—••«	JAMESTOV/N

	NEV/PORT

	  PAWTUCKET
          Figure 12.  Rhode Island -  Surface Waters

Reprinted (with modification) by Permission from Ref. 291
                          49

-------
magnitude follow a regular pattern over time.  This feature hampers
the development of a micro-analytical cost model for water supply con-
tamination.

The conceptual issues are compounded by problems of data availability.
Neither the direct nor the indirect costs of excessive levels of sodium
and chloride in drinking water have been measured in a comprehensive
manner at any level of aggregation.  For example, even simple cost
items (such as the costs of more frequent testing once chloride levels
are approaching threshold levels) cannot be culled from existing expen-
diture records, since accounting procedures at the local or state level
tend to lump these costs with expenditures on routine activities.  The
empirical evidence required for the cost analysis at the necessctry
level of detail thus often simply does not exist.

Finally, apart from the problem of the appropriate conceptual framework
and data availability, the analysis also has to cope with a serious
issue of a more philosophical nature.  Probably the most important
indirect cost of salt contamination of drinking water supplies is
related to the health effects of increased sodium intake by users.  High
levels of sodium intake have been found to contribute significantly
to increased morbidity and shortened life expenctancies (e.g., in 134).
The evaluation of such effects in economic terms faces a number of issues
that have been debated in health economics for some time.  While several
methods have been developed to "cost out" the detrimental effects of some
substance or factor on public health, none of these.techniques resolves
the basic philosophical dilemma — placing a dollar value on human life.
Generally, the costs of ill health can be measured by including direct
expenditures on diagnosis and treatment, as well as the opportunity
costs of losses in productive activity, i.e., 'the value added foregone
by society.  While this approach is useful in a purely economic context,
it has the serious drawback that the ill health of "non-productive"
members of society (persons outside the labor force) cannot be directly
evaluated in this manner.  The analysis below therefore provides! only
estimates of the likely ranges of health effects, without attempting to
translate them into dollar figures.

Given the problems of conceptual complexity and of observation and
measurement for estimating the costs of salt contamination of drinking
water supplies, the approach taken here focuses on the development of
a comprehensive framework designed to cover all direct and indirect
cost elements on a per capita basis.  The cost model is subsequently
used to explore the range of likely total costs on the basis of avail-
able information and reasonable assumptions about specific unit costs.
This discussion is followed by an assessment of the principal health
effects associated with increased sodium levels in drinking water
supplies.
                                    50

-------
5.2.1   Cost Estimate Framework

As noted in Section 5.1, several dimensions of the cost analysis can
be distinguished.  For the costs resulting from the chloride and
sodium contamination of drinking water supplies, the general breakdown
can be illustrated by means of selected examples shown in Table 1.
This breakdown distinguishes direct and indirect costs.  Direct costs
involve expenditures or use of resources to remedy any damages related
to salt contamination.  Indirect costs can be viewed as damages to
individuals or society as a whole that involve a reduction in the level
of welfare of the party or parties concerned without requiring any direct
outlays.
                                Table 1

                 Dimensions of Costs Associated with
                 Salt Contamination of Drinking Water

                       (with Sample Cost Items)
Cost Type
Direct
Indirect
Cost Incidence
Individuals
Cost of replacement
of private wells as
a result of the
contamination of
existing wells-
Losses in private
property value in
areas exposed to
the risk of drink-
ing water contam-
ination through
deicing salts.
Society
Cost of installa-
tion of special
drainage ditches
and catch basins
to keep salt runoff
from water supplies .
Losses in value
added as a result of
the reduced produc-
tive capacity of
individuals with a
hypertension condi-
tion exacerbated by
sodium in drinking
water . *
 *  Largely a cost to society,  since individuals are at least partially
 compensated through some form of transfer-payment.
                                     51

-------
In terms of the incidence of costs, two major groups can be distin-
guished: government  (at all levels) as a representative of society
as a whole, and individual members of society.  Although this distin-
ction is somewhat arbitrary, it is useful by allowing for a more
detailed breakdown of the types of costs incurred as a result of the
contamination of drinking water supplies.  In addition to contributing
to a more structured analysis, the distinction also allows for an
assessment of the equity implications of alternative institutional
arrangements.  One example may illustrate this point.  As a consequence
of the application of deicing salts, private wells have become contam-
inated in several states.  In most areas, it is the primary responsi-
bility of the individual well owner to finance measures necessary to
cope with this problem, at least ,in the shortrun.*  In-a few instances
this problem has been reflected in losses in property value that can
be directly attributed to the salt problem.  The incidence of costs
can be shifted from affected individuals to society.  There is at least
one instance in which the state has accepted the responsibility for
any costs related to the contamination of private wells through deicing
salts.  New Hampshire instituted a well replacement program as far
back as 1956, with the state paying for the replacement of:wells that
have been determined to be contaminated by salt runoff from highways
(265).  While this program does not imply a complete shift of the cost
burden from the individual to society as a whole (there is a substan-
tial waiting period involved, partially because of the large volume of
claims), it may result in a more equitable distribution of the net
costs  (or net benefits) of the use of deicing salts.  The discussion
will return to an examination of the equity aspects below.!

The examples shown in Table 1 .suggest some of the difficulties of
delineation of cost categories.  Particularly in the area of direct
vs. indirect costs, a general line cannot be drawn.  Too much depends
on the particular arrangements and the extent to which water contamin-
ation may go unnoticed.  The discussion below therefore focuses on
the cost implications of remedial measures that restore affected water
supplies to their original quality (e.g., through well replacement).
The analysis of indirect costs focuses on health effects only.

Direct Costs —

The identification of the relevant direct costs to either society
or individuals calls for a look at the process which gives rise to
these costs.  Since the contamination of drinking water supplies is
* There are of course several possibilities in the longer term to
shift any costs to society, for example, by lobbying successfully for
any form of compensation, or for the construction of special drainage
ditches that will prevent salt runoff into private wells.
                                   52

-------

primarily a public health problem, analogies from medical care can be
used to structure the cost-generating process.  The direct costs in-
curred by either water supply agencies or users of public or private
water supplies can be grouped into three broad categories: the costs
of prevention, of diagnosis and of treatment.

     Prevention:  The growing awareness of the potential impact of
the use of deicing salts on the contamination of public or private
water supplies with chlorides and sodium has led to an increased
emphasis on preventive measures.  These measures include the installa-
tion of special drainage ditches and catch basins for salt brine run-
off from highways, the selection of well locations at a sufficient
distance from highway drainage areas, the incorporation of water supply
locations in highway route planning, and any other measures designed
to lower the chances of infiltration of salt brine runoff into private
or public water supplies.

     Diagnosis;  Practically all public drinking water supplies are
monitored on a periodic basis with respect to a variety of constituents.
As a result of the accumulating evidence concerning sodium and chloride
contamination, these monitoring activities have been stepped up in a
number of instances.  For example, the State of Massachusetts tradi-
tionally had limited its tests to the determination of chloride levels
 (together with a variety of other substances).  Recent concerns over
the salt contamination of drinking water supplies have led to the intro-
duction of sodium tests as part of the regular monitoring procedure in
1970  (see 53).  Diagnostic costs also include outlays for studies
designed to identify the source(s) of observed contamination problems,
assess their implications for the future, and determine appropriate
remedial steps.  Finally, the category of diagnostic costs also covers
all incremental expenditures incurred in handling user complaints and
inquiries and in following up on specific cases.  Such costs apply,
for example, to the U.S. Environmental Protection Agency's mandate to
participate in the supervision of"drinking: water quality.

     Treatment;  Once a serious contamination problem has been identi-
fied, persons responsible for a given water source  (either public
or private) have to take some form of remedial action.  The definition
of a "serious contamination problem" may vary across the  snowbelt
region.  In terms of chloride, most states and local water supply
agencies focus on the recommended limit established in 1962 by the Public
Health Service at 250 mg/1.  However, in several instances, levels con-
siderably below this limit have been taken as a cause for action.
Particularly with the increasing  concern over the sodium  content of
drinking water supplies, chloride levels as low as 30-70  mg/1 may be
cause for concern*.
 *   While the relationship between sodium and chloride  contamination
 varies  in response to soil  consistency  and precipitation patterns, a
 rough guideline is a ratio  of 2:3 to 1:3.  A chloride  level  correspon-
 ding to a sodium concentration of over  20 mg/1 may  therefore be  cause
 for concern.
                                    53

-------
Remedial action or treatment may assume several forms.   Itjmay range
from modifications of the current water supply system and its environ-
ment to a complete replacement of the water source bv some alternative.
Modifications of the current system include, for example, attempts to
reduce the chloride or sodium concentration by "flushing" the well,
changes in drainage system for the area (which may involve;the instal-
lation of special drainage ditches or the implementation of any of the
other measures discussed under prevention), or reduction of production
from the affected well(s) in the hope that sufficient dilution will
occur.  Such measures are likely as long as the observed concentrations
do not yet pose a public health problem.

Once the concentrations approach or exceed the critical level — generally
defined in terms of the recommended chloride limit of 250 mg/1 — the
principal course of action followed by public water supply officials
or users is the switch to other water sources.  The cost implications
of such a course of action vary considerably with the characteristicss
of the system.  For example, a town that is dependent on one main well
may have to purchase water from other sources at substantial additional
cost, or may have to invest in the development of a new well.  In con-
trast, a town employing a number of wells may just have to[increase
production from non-affected wells to replace a well that had to be
closed because of chloride contamination.  For private water supplies
affected by salt runoff, the only alternative is generally;the drilling
of a new well, preferably at a sufficient distance from the highway
drainage area.  Several studies have indicated that a .minimum distance
of approximately 15 meters from the highway shoulder is necessary to
reduce the likelihood of deicing salt contamination of private water
supplies, e.g., (95), on some lots such as relocation may be difficult,
because of the location of the septic system.             :

Another possibly major  cost element is the reaction of users to current
sodium levels in drinking water.  Persons on a low-sodium diet for medi-
cal reasons may become concerned over the possibility of excess sodium
in their drinking water, preferring instead to purchase bottled water
(which may or may not be "pure").  Without a specific survey, it is
impossible to predict what percentage of the population follows such
a course of action.  Here again, it is important to remember that sodium
concentrations vary randomly as a result of natural factors or because
of variations in the amounts of salt applied.  Since it is: virtually
impossible for the individual user to test the drinking water himself,
his or her decision as to the use of tap vs. bottled water generally is
based on haphazard information from the media, or responses to inquiries
to water-supply agencies.  This information base tends to leave a sub-
stantial uncertainty.  Given the potentially high risk for individuals
with a hypertension condition, the best course of action may be to pur-
                                    54

-------
chase bottled water.*  The likely costs of these purchases must be
included under the treatment, category.

These considerations establish a basis for listing the major direct
cost items associated with the contamination of drinking water supplies
by deicing salts.  Table 2 presents a fairly comprehensive list of
these cost items, together with an assessment of the relative magnitude
of the costs and the likelihood of their occurrence.  The assessments
of magnitude and occurrence are based on the evaluation of the relevant
literature.  As noted above, no comprehensive data base exists that
would allow for a complete enumeration of cost elements and their like-
lihood of occurrence.  The analysis therefore must be based to some
extent on best judgment.

The distinction of magnitude and likelihood of occurrence is necessary
to obtain a representative estimate of total social costs.  The dis-
cussion above has mentioned that the degree of water contamination
varies over time in response to a variety of environmental factors.
The process which causes direct costs  (as well as indirect costs)
therefore is a random process.  Since  complete data on the behavior of
these processes in the past are not available, the total direct costs
cannot be evaluated directly.  Any cost estimate therefore becomes an
expected cost -- the product of the actual costs and their probability
of being incurred.

This point deserves additional emphasis.  The direct  (and indirect)
costs associated with the actual contamination of drinking water sup-
plies vary as a result of two factors.  First, the physical processes
leading to contamination levels are strongly subject to random varia-
tions in the occurrence and strength of important factors involved.
Secondly, for the same level of contamination, any direct cost may
vary considerably over time and across regions and towns as a consequence
of differences in reaction on the part of those responsible, and in
relation to differences in environmental and economic conditions.  Since
action alternatives  to municipal and state officials  are generally
delineated in terms  of budgetary constraints, actual  direct costs may
be higher in more affluent towns or states.  While  these differences
are  at least partially offset by differences in indirect costs,  economic
factors may produce  substantial variations in the type of response and
the  associated costs.  Under these conditions, representative expected
costs  constitute the principal option  for the analysis.
 *  A Massachusetts highway official acknowledged that this  may be the
 best alternative to hypertensives by suggesting, perhaps  somewhat cyn-
 ically, that the state would still be better off by continuing its cur-
 rent salting policy and supplying hypertensive individuals  with bottled
 water.  (Quoted in the Boston Globe.)
                                     55

-------
                                Table 2

                   Direct Costs Associated with Salt
                Contamination of Drinking Water Supplies
   Cost Factor
Relative Magnitude
    of Costs
 Likelihood of
  Occurrence ;
                                                              Incurred by
 Prevention

   Installation of
   drainage ditches
   along highways

   Location of  new
   private  wells beyond
   12 meter strip  along
   salted highways

   Maintaining  a suffi-
   cient distance  from
   water supplies  in new
   highway  routing

   Reduction of the
   salt/sand ratio used
   in application
  Improved monitoring
  of likely salt needs
  and actual salt use
  by individual
  spreader trucks

  Purchase of land
  around public water
  supplies
    Medium
 Generally low
 Generally low,
 but may add
 signicantly to
 costs

 Extremely low,
 probably nega-
 tive (i.e.,
 savings)
Nominal
Medium-High
 High  for
 "bare pave- !
 ment" highways

 Low,  only  for
 new develop-'
 ments
Low, only for
new construc-
tion
High, likely
to be included
in all winter
highway main-
tenance

High, likely
to be included
in all winter
highway mainf
tenance
Medium
                                    Society
                                    Individuals
Society
                                                              Society
                                   Society
                Society
Diagnosis
  Increased monitoring
  and testing of water
  supplies
Low
                   High
                Predomin-
                antly
                Society
                                   56

-------
                           Table 2 (Continued)

              Direct Costs Associated with Salt Contamination
                        of Drinking Water Supplies
  Cost Factor
 Relative Magnitude
     of Costs
 Likelihood of
  Occurrence
                                                              Incurred by
  Studies' to determine
  causes of observed
  contamination and
  identify appropriate
  treatment
 High
 Low,  but
 increasing
 Predomin-
 antly
 Society
  Studies/tests to
  ascertain role of
  deicing salts in
  contamination of
  private wells

  Handling of com-
  plaints and inquiries
  concerning sodium
  chloride contamina-
  tion of public water
  supplies
 Low to medium
                    Low, but
                    increasing
Nominal per  case
Medium,
Increasing
                Predomin-
                antly
                Individuals
 Society
Treatment

  Replacement of con-
  taminated private
  wells
  Purchase of water
  from other sources

  "Flushing" of con-
  taminated wells
High
               Generally
Low to medium  individual
               but may be
               society
               (N. H.)
Medium
Medium
                    Low
                    Low
               Individual
               and Society

               Society
  Installation of
  protective devices
  (drainage ditches,
  catch basins)

  Replacement of
  contaminated
  public wells
Medium
High
                    Low
Very low
thus far
                                   Society
Society
                                   57

-------
Indirect Costs —

Principally, all indirect costs associated with the contamination of
drinking water supplies through deicing salts relate to the health
effects   While it may be possible that water users experience a loss
in welfare as a result of bad-tasting water, the costs of chloride con-
tamination  (below the threshold level of 250 mg/1 established by the
Public Health Service standards) are primarily in the nature of direct
costs   The discussion here therefore deals primarily with the potential
health effects of comparatively high levels of sodium in the drinking
water   Because of the role of this public health hazard, ;the analysis
focuses on health hazards related to hypertension  (high blood pressure).

The evaluation of the indirect costs related to these health effects is
difficult,  since they can assume different forms.  The discussion of
direct costs above already indicates that such indirect costs can be con-
verted into direct expenditures, if the individual concerned decides to
forego public  (or private) water supplies as a source of drinking water
and purchases bottled water instead.  In other cases, the;risk of any
adverse health effects associated with the drinking water,quality in a
particular  town may  result in direct economic losses in terms of property
values.

The problem of indirect  cost  evaluation is  further complicated by the  role
of ignorance  and uncertainty  in determining  the  actual health effects.
Under conditions of  perfect information,  the opportunity  cost of  sodium
 contamination in drinking water supplies would be  the  cost of supplying
 individually  approximately  20%  of  the population who are  or should
be on a low-sodium diet with  "pure" water for  drinking purposes,  e.g.,
 in the form of bottled water.  However,  since  this option has been  rarely
 exercised,  the appropriate  cost measure refers  to  the likely health effects
 of higher sodium levels  in drinking water supplies which are in fact con-
 sumed.   Based on these considerations,  the exploration of the  empirical
 dimensions of the problem below focuses on the likely health effects
 actually caused by the salt contamination of drinking water.


 5.2.2   Review of the Empirical Evidence

 As noted above,  no effort has been undertaken to measure direct or indirect
 costs of the salt contamination of drinking water supplies in any compre-
 hensive form at any level of aggregation.  The thorough review of published
 and unpublished literature as well as the survey of operating agencies
 conducted  as part of this study yielded very little useful information
 that would allow for an estimation of direct or indirect costs for more
 than specific instances.  The approach here therefore reviews briefly the
 relevant information that has been obtained, and uses this information
 to derive  some broad indicators of costs on a per capita ;basis, which
 can then be used to delineate the range of total costs associated with
 the contamination of drinking water supplies.
                                     58

-------
Direct Costs —

Probably the best data base for an evaluation of the likely range of
direct costs is available for New Hampshire.  The State of New Hampshire
has shown considerable concern with the effects of highway salting
policies on the environment, particularly water supplies.  This concern
has led to the institution of a well replacement program as early as 1956
(265).  The program operates on a complaint basis only.  The wells affected
must be located near state-maintained roads.  Well inspectors observe a
well which has been contaminated for a year to determine whether the contam-
ination (chloride level) is significant over a three to four month period.
In order to quality for the replacement program, chloride levels must be  #-
iround the 1962 PHS recommendation of 250 me;/l. However in practice a number of
considerations are involved in determining^'whether a well should be replaced.
Corrective action generally requires-about a year to 18 months.  The state
will replace the well and the pump, once it has been established that the
well is in fact contaminated as a result of state salt runoff from high-
ways .

Budgeted for this program is an amount of $200,000 per year (up from
$100,000 prior to 1973) for.the well replacement itself.  In 1974, 50
wells were replaced at a total cost for labor and materials of $132,000.
Table 3 shows the number of wells replaced since 1965 and the associated
total costs and costs per well.  There is no evidence for any trend in
the figures, except for a long-term increase in the cost per well,
(although these costs have declined over the last three years), which is
attributable to inflationary patterns.  Aside from this trend, cost per
well varies considerably over the years.  These variations tend to reflect
variations in construction conditions.  For example, additional costs are
incurred, if deeper wells have to be drilled or more elaborate pumps
(other than simple jet type pumps) have to be installed.

The costs shown in Table 3 only refer to the direct costs of well replace-
ment.  In addition, the Special Services Division of the New Hampshire
Department of Public Works responsible for the well replacement program
maintains a payroll of about $80,000 (1974).  The actual costs of^operating
the program also include maintenance and depreciation for five cars, the
costs of approximately 200 water samples annually, and any costs incurred
as the result of drainage corrections requested by the Division and imple-
mented elsewhere.  (265)

All these costs taken together amount to approximately $0.25 per capita
per year.   Since the well replacement program only refers to wells contam-
inated by state salt, the actual required costs for maintaining an ade-
quate water supply in New Hampshire are higher.  Given that state salt
amounted in 1972 to approximately 24.5 percent of the total for the state,
the total direct costs associated with deicing salts in New Hampshire may
amount to $1.00 per person,- or $700,000 for the state as a whole.  While
this figure appears very high, it should be kept in mind that it would
constitute a catch-all figure for all the direct costs that would be
                                     59

-------
                                Table 3

                 Costs of New Hampshire Well Replacement
                                 Program
Year
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
Number of Wells
Replaced
44
53
62
42
40
38
17
30
27
50
Costs
(in thousands)
$ 80.3
128.4
109.4
85.6
97.8
85.6
41.9
93.9
77.5
132.0
Costs per
Well
$ 1,8.25
2,421
;i,765
,2,038
2,329
2,253
. 2,465
3,130
2 , 870
2,640
involved in restoring a water .supply system to a state characterized by
tolerable levels of chloride contamination.  In this sense, it can be
regarded as a total expended cost figure.

Extrapolation of this figure to the U.S. as a whole is difficult.  It would
be misleading to use the per capita cost figure for New Hampshire as indi-
cative for all other states.  At a minimum, two factors must be taken into
account:  salting intensity (total salt per lane mile) and;the relative
importance of wells, which are much more susceptible to salt contamination
than reservoirs, as sources of the population's water supply.  Using only
salting intensity by state as a weighting factor for extrapolation, the
New Hampshire per capita costs to the nation yields a total cost estimate
of $46.5 million per year.  Since New Hampshire tends to rely on ground-
water as sources of water supply at a slightly lower rate than the nation as
a whole (20% vs. 21%), the potential cost of replacing contaminated wells
would be slightly higher.  However, the available evidence, scant as it
                                    60

-------
is, suggests that this figure may not be too high.   The following para-
graphs summarize illustrative examples that have been identified in the
literature search and contacts with practitioners in the field.

Perhaps one  of  the most visible  examples of well contamination and related
public debate has been the  town  of Burlington, Massachusetts.  In the  late
1960s, Burlington experienced the contamination of wells as a  result of
road applications and storage.   The main water station was closed down
because of a chloride content of 283  mg/1.  According to estimates prepared
by the U.  S. Geological Survey,  40% of  the  contamination problem could be
attributable to salt use  (both application  and storage) by the town of
Burlington,  30% to applications  by  the  Massachusetts  Department  of Public
Works (primarily on  Route 128, a major  circumferential artery),  and 15%
to applications by the neighboring  town of  Lexington.  The remaining 15%
was  attributed to septic tanks  and industrial  contamination.

City officials  indicated  no particular  costs  as  a.  result of the  shutdown
of the main water  station/  since production from nine other wells  less
affected by the contamination problem could be  increased to cover  the
demand.   Other than  outlays for  an engineering  study to determine  the
 causes  of the  problem and identify simple remedial measures  (approximately
 $15,000), no additional  costs have been recorded.   This particular statement,
probably neglects  a  number of costs that may have  been incurred, such
 as the  actual  costs  of closing the well,  incremental costs  of increasing
production from other wells, more frequent testing during  the period of
higher contamination levels, outlays for the changes in the drainage sys-
 tem recommended in the engineering study (114), and any costs  that have
 been incurred as a result of intensive debate in the town regarding the
 advisability of a ban on street salting which was  subsequently implemented
 for a two-year period.   While these costs may be comparatively small  for
 a town with 20,000 inhabitants,  similar costs for the nation as a whole
 could be sizeable.

 A different situation occurred in Goshen, Massachusetts,  which experienced
 the contamination of seven wells which are owned privately, and one well
 owned by the local school committee.  The source of  the problem has been
 primarily the application of salt on nearby Route 9, also a highly frequented
 highway.   The  contamination was first noted in 1972; subsequent readings
 have failed to  show  any significant improvement.  Several homeowners whose
 wells were affected by the contamination problem have placed their homes
 for sale at expected losses to them.   (Further investigation could not
 determine the size of these expected losses.)  Others have incurred signi-
 ficant costs for drilling new wells and replacing  pumping equipment and
 pipes.

 The School committee was forced to close the contaminated well and pur-
 chase bottled water for the school years between December 1971 and March
 1973, a total cost of $650.  The state has responded to the problem by
 building a drainage system along a quarter mile stretch near the affected
 wells in order  to carry the salt runoff further down the road.  This
                                       61

-------
 effort was partially successful for the wells affected,  but resulted in
 the contamination of yet another well.   Efforts  by the town to have  the
 wells replaced by the state have failed.*

 Two final examples may round out this review of  some of  the evidence
 gathered in the study: two towns in Massachusetts, Weston and Norwell,
 both experienced severe contamination of their water supply because  of
 salt application and storage.  As a result,  their wells  had to be  closed.
 The new wells cost approximately $150,000 in each of the two towns.+

 Given this evidence, the estimate obtained above on the  basis of more
 detailed data for the State of New Hampshire does not appear to overstate
 the total direct costs incurred by society and individuals as a result
 of the contamination of water supplies  through deicing salts.


 Indirect Costs —

 The evaluation of indirect costs of salt contamination of drinking water
 supplies is hampered by conceptual problems,  as  indicated above,, and by
 more severe data problems.   Many of the examples of well contamination
 that have been encountered were defined in terms of chloride levels.  Com-
 paratively little is known about the incidence of sodium.  While  data on
 chloride levels are widely available (and have been used to .study  the
 relationships between road salting and  water contamination),  comparatively
 little has been done to monitor sodium  levels.   Any inferences  concerning
 the relationship between road salting and sodium contamination  therefore
 rely on the "rule of thumb"  that sodium reaching water supplies is approx-
 imately one-third to two-thirds of the  corresponding amount of  chlorides.

 These factors make an assessment of the absolute magnitude of health
 effects a rather uncertain undertaking.   Review  of water quality monitoring
 data indicates that in Massachusetts, approximately 27%  of the  towns  and'
 cities have one or more water supplies  with  a sodium level above* 20 mg/1
 which can be taken as  a cutoff point beyond which the water may constitute
 a  serious health problem for the 4% to  5%  of  the population on  low-sodium
 diets,  or the 10% to 25% who have been  estimated to be affected by hyper-
 tensive conditions.  However, very  little evidence in terms of epidemio-
 logical studies relating  cardiovascular diseases  (primarily hypertension)
 to sodium  in drinking water is available.  Part of the problem is  that
 the recognition of the role of sodium in cardiovascular disease has been
 established firmly only recently.

Research on the relationships between characteristics of  drinking  water
and cardiovascular diseases focused originally on the hardness of  water.
In 1960, Shroeder published a paper showing a negative correlation between
the water hardness of potable water and cardiovascular deaths.  This
finding was confirmed in a number of subsequent studies.   A study  published

 *  Personal communication with the Chairman of the Board  of Health, Go.shen,
 Massachusetts, May, 1975.

 *  Personal communications with Massachusetts  Public Health Department,
 May,  1975.
                                    62

-------
in 1967 in a Russian medical journal (329) indicated a statistically
significant difference in the incidence of hypertension among two groups,
one using water supply with a "normal" amount of sodium, the other using
water supply with an "elevated" sodium content.  These results are some-
what problematic to .interpret  since "normal" and "elevated" were insuf-
ficiently defined.  According to Wolf and Moore (145), "normal" in this
article referred to a sodium level of 263 mg/1 and less, while "elevated"
sodium concentrations were in the range of 470-1180 mg/1.  These levels
are not typical for sodium concentrations in drinking water attributable
to deicing salts.

Wolf and Moore (145) used data for areas in Dallas County, Texas to
examine the possibility of any association between sodium content of the
drinking water and cardiovascular deaths.  Grouping communities into low
sodium water supplies and high sodium water supplies, the authors then
compared weighted average (cardiovascular) death rates per 100,000 for
the two groups.  The results of this comparison are shown in Table 4»
Except for men in the age group 45 - 59, death rates are significantly
higher for the high sodium communities.  The authors suggest that the
exception may be due to the fact that men in this age group tend to be
economically active, spending a major portion of their time in the city
of Dallas (a low sodium community).

The implications of these differences in age-specific death rates can be
illustrated by examining their implications for a sample group.  For the
60 - 74 age group, the difference in death rates between low and high
sodium communities is 400 per 100,000, or .004.  If this figure holds
generally, the age-specific survival rate would be lowered by this differ-
ential.  For men in the age group 60 - 64, the national survival rate
is approximately .835.  This rate corresponds to an average life expectancy
for men in this age group of 5.6 years.  If the survival rate is lowered
by .,004 to .831, the average life expectancy declines to 5.4 years.  Higher
levels of sodium concentration in the drinking water thus would imply a
reduction in the life expectancy for this age group by almost 4 percent.
Extrapolating these data to the national level is impossible because of
the limited nature of the study and because of lack of data relating
to the incidence of sodium concentrations in drinking water over a suffi-
cient time period.

An indicative estimate of the cost of salt contamination of drinking
water supplies in terms of their health effects can be obtained by esti-
mating the expenditures required to remove the hazard.  A rough assessment
of the total cost can be obtained by assuming that all people affected
by conditions of hypertension would purchase bottled water for drinking
purposes, once their water supply exceeded a sodium concentration of 20 mg/1.
For the normal adult, an average drinking water consumption of 2.2 liters
has been estimated.  This estimate can be used to obtain a rough estimate
of the potential cost of supplying all persons on low-sodium diets affected
by sodium concentrations over 20 mg/1 with bottled water.  A gallon (3.8
liters) of bottled water sells currently for about $.50.  The average
person would therefore spend approximately $106 (2.2/3.8.365.50)  per year
to satisfy his or her drinking water needs entirely through bottled water.
                                     63

-------
                               Table 4

             Differences in Cardiovascular Death Rates
          For Different Levels of Sodium in Drinking Water
                            (per 100,000)
    Age Group
     High Sodium*
                                                     Low Sodium
    45 - 59


    60 - 74
 Males

  375


1,730
Females

  91


 990
 Males

  447


1,330
Females

  74


 570
              * 120 mg/1 or more
              +  25 mg/1 or less


The number of persons on low sodium diets exposed to sodium concentrations
in the drinking water above 20 mg/1 attributable to road salt is extremely
difficult to estimate.  The Massachusetts' experience indicates that appro-
ximately 27% of the water supplies (not necessarily the population)  are
affected by high sodium concentrations attributable to road salt.  As a
broad estimate, it can be assumed that roughly 25% of the population under
conditions similar to those in Massachusetts are affected. :Four percent
of the population have been estimated to be on a low-sodium diet.  Using
salting intensity as a weight to make other states in the snowbelt com-
parable to Massachusetts yields an estimated total cost for ithe nation of
$105 million.  Since Massachusetts relies more heavily on groundwater
than the nation as a whole (23% vs. 21%), the estimate should be somewhat
lower, i.e., $96 million.

In summary, the direct .and indirect costs of water supply contamination
may add up to almost $150 million nationwide.  This figure provides an
impression of the magnitude of the damages, rather than describing actual
costs.  It should be noted that the considerations in this section do not
include any costs to industry as a result of special requirements for
processed water.
                                     64

-------
5.3   COSTS OF DAMAGES TO VEGETATION

Experiments and empirical studies have clearly demonstrated that  (a)
many of the trees used for roadside planting in the snowbelt (notably
sugar maples) are sensitive to increased sodium concentrations in the
soil, and  (b) there is a direct link between the deterioration or death
of roadside vegetation and salt application.

Essentially, roadside vegetation (whether public or private) may suffer
as the result of two major factors.  First, vegetation may be affected by the
runoff of salt brine and the retention of sodium ions in the soil.  This
possibility is particularly acute in highway stretches characterized by
conditions that favor a fast runoff of salt brine from the road surface
to the area of vegetation, combined with a comparatively poor drainage
in the area itself.  The second, possibility, which impacts particularly
upon shrubs and hedges in urban areas, is the practice of dumping salt-
saturated snow along the edges of the road,, after plowing. This practice
may lead to extremely high salt concentrations around the plants affected.
Since many of these plants are characterized by shallow root systems, and
since much of the sodium remains in the upper layers of the soil, destruc-
tion of shrubs and hedges is a common occurrence.

However, most of the research on the effects of deicing salts on roadside
vegetation has focused on the damages to trees along suburban and rural
roads.  The affected strip extends approximately 9 to 12 m from the edge
of the road.  Salt concentrations beyond this distance in the soil have
been found to be negligible.  Within this strip, salt affects vegetation
in two ways.  Firstf it directly interferes with the chemical processes
by which plants absorb nutrition; it affects the osmotic balance, thus
inhibiting the water intake of plants, and it may replace vital nutrients.
In addition to these direct effects, sodium in the soil may also result
in a rapid deterioration of the soil itself.  According to Westing (191),
"...when sodium comes to occupy more than about 15% of the total cation
exchange capacity of the soil, soil structure begins to deteriorate.
...permeability and water-holding capacity decrease markedly."

While the botanical and chemical evidence is sufficient to suspect wide-
spread deterioration of roadside vegetation in areas characterized by
the heavy use of deicing salts, the empirical backup is somewhat meager.
Aside from studies of specific stretches of highway and their vegetation
(such as Button [156, 157]), the data base relating to the interaction
between deicing salts and vegetation damage at a macroscale is limited to
reports of specific instances.  For example, Rich (175)  reports that in
1957, the New Hampshire Highway Department removed 13,997 dead trees
along 3,700 miles of highway.  The estimated cost of removal was $1 million
or more than $70 per tree.  According to other reports,  Winchester,
Massachusetts, which has applied as much as 55 tons of salt per mile, has
lost an average of 56 trees per year since 1963. (26)   Similarly, Newton,
Massachusetts which also tends to apply salt amounts far above the average
for towns and cities in the state,  is reported to have lost about 500
                                      65

-------
trees per year between 1965 and 1970 (40) .

The problem with, the evaluation of these reports is that they tend to
relate tree deaths from all causes to salt application.   Since no national
statistics are available concerning the number of dead trees per year,  it
is impossible to identify the net effects of deicing salts in terms of
damages to roadside trees statistically.  Similarly, data on the population
at risk (i.e., roadside trees possibly exposed to deicing salt runoff),
which would be useful in applying micro-analytical findings to a macro-
level framework, are unavailable.

As a result, national damage estimates simply cannot be generated.  The
following discussion therefore explores possible cost ranges, including
both direct and indirect costs associated with tree damage that can be
related to deicing salts.  Direct costs relate to the cost of maintenance
and removal in the case of death, while indirect costs concern the losses
in welfare to society or individual property owners resulting from the
disappearance (or deterioration) of a fully grown shade tree, which may or
may not be replaced by a small young tree.  From a conceptual point of
view, it is of course the evaluation of indirect costs that constitutes
the most difficult task.

Fortunately, a number of studies have been undertaken to determine the
monetary value of shade trees.  According to the International Shade
Tree Conference  (169), three basic factors must be considered in deter-
mining the monetary value of a shade or ornamental tree: size, kind and
condition of the tree.  Tree size is generally measured in terms of dia-r
meter at breast height  (dbh), where breast height is defined as 1.37 meters
above ground.  In August, 1973, the International Shade Tree Conference
adopted $10.00 per square inch  (1.55/sq. cm) of truck cross-section as
the conservative value of a perfect specimen shade tree.  Table 5 presents
the base values of shade trees for different dbh values.  This material
would imply, for example, that the indirect costs associated with the
New Hamsphire example mentioned above would add about $10 million to the
direct costs  (using a fairly conservative average of 10-inch  (25.4 cm)
dbh for the 13,997 trees removed.)

While the measures established by the International Shade Tree Conference
may be somewhat arbitrary and, more importantly, apply primarily to
urban trees, they provide an indication of the potential magnitude of
the problem.  If only 6% of all tree deaths in the New Hampshire  example
can be attributed to deicing salts, the total cost  figure,  including
both direct and indirect costs, would be comparable to the  total  costs
computed for the water  contamination damages, or $46.5 million.
                                     66

-------
                                Table 5

                     Basic Values of Shade Trees
                  (For Perfect Specimen Shade Trees)
       Trunk Diameter
          Inches
Cross Section Area
  Square Inches
Basic Value (in
   Dollars)*
2
5
10
15
20
25
30
35
40
45
50
55
60
3.14
19.64
78.5
176,7
314.2
490.9
706.9
926.1
1,256.6
1,590.4
1,963.5
2,375.8
2,827.4
31
196
785
1,767
3,142
4,909
7,069
9,621
12,566
15,904
19,635
23,758
28,274
Calculated on the basis of $10.00 per square inch (1.55/sq. cm) of cross-
section trunk area at 4.5 feet (1.37 m) above ground.
(Note:  One inch = 2.54 cm; one square inch = 6.45 sq. cm.)
                                    67

-------
5.4   COSTS OF DAMAGES TO HIGHWAY STRUCTURES

Deicing salts contribute to the deterioration of bridges, decks and
supporting structures, highway surfaces and other highway istructures.
The review of the available evidence on the physical and chemical
processes involved, presented in Section 4.2.2, provides the background
for an exploratory assessment of the cost implications of the incre-
mental damage caused by deicing salts.  This assessment focuses on
bridge decks, since the technical evidence of causal relationships is
most convincing in this case.

The true cost to society of salt-induced bridge damages includes direct
outlays by highway departments for activities such as inspection, repair,
and replacement, as well as indirect costs to the public including
that portion of Federal research outlays, vehicular deterioration, lost
time, and increased accidents which may be attributed to the use of salt
(e.g., rear end collisions in traffic lines resulting from repair work).
This section first summarizes the direct costs, presents a partial
analysis of the indirect costs, and finally gives an estimate of the
full social costs of salt damage to the nation's highway bridges.  The
cost estimation approach is characterized by extreme conservatism; areas
in which  the available evidence or required data are either not avail-
able or not sufficiently reliable are treated with deliberate skepticism.
This procedure implies that the total cost estimate describes the lower
boundary of the actual costs.

5.4.1  Direct Costs

The actual cost outlay by state highway departments for the repair of
bridge decks was estimated to be $40 million or more in 1971. (230)
This estimate of private costs is conservative in that it -ignores the
costs of installing improved design features such as waterproof mem-
branes in new bridges, and also because maintenance on spalling decks
has been insufficient to maintain a constant average quality.  The
result is a substantial understatement of true costs.  Outlays for
repair that would halt the deterioration in quality were estimated by
Kliethermes to be some two to three times actual expenditures, or $80
to $120 million*

Recent evidence from individual states, particularly West .Virginia,
provides a check on Kliethermes' cost figures.  The cost of maintaining
West Virginia's 6,000 bridges in good condition was recently estimated
to be approximately $12 million, or about $2,000 per bridge.  The
number of bridges affected by salting of the nation's highways can be
derived from a map in the Kliethermes article  (230) which depicts
regions of severe, moderate, and no deterioration throughout the country.
* Personal communication with J. Kliethermes, Federal Highway Administra-
tion, December, 1974.
                                   68

-------
Although the total number of highway bridges was readily obtained, the
number  in each state could not be determined, and it became necessary
to  estimate their distribution.  Following a suggestion of Adrian Clary*,
of  the  Transportation Research Board, the distribution of bridges
was estimated in proportion to the distribution of the human population
throughout the country.  Using Kliethermes1 data on regional damages
as  shown in Figure 13 and assuming that 100% of the bridges located in
severe  regions require periodic maintenance and repair of salt induced
damages, whereas only 20% of the bridges in moderate regions are so
affected, we conclude that nearly 100: thousand bridges are adversely
affected.  Assuming that the West Virginia estimates are representative
of  costs in other severe deterioriation regions, a yearly cost for the
nation's bridges of $200 million is estimated"*".

This of course provides only a rough overall estimate.  A more differ-
entiated approach, using microeconomic cost data for each of the possible
activities related to the detection of salt-related damages, and
resulting repair and replacement, could be employed to explore the imp-
lications of alternative damage configurations for highway bridge decks.
The microeconomic cost data are summarized in Table 6.
* Personal communication with Adrian Clary, November, 1974.

+ During the winter of 1969-1970, West Virginia used an average of 3
tons of salt per lane mile and 20 tons of salt per bare pavement lane
mile.  (Not all roads are required to be kept bare; thus these figures
may be very different in some states.)  Many other states in the snow
belt exceeded these figures, for example:
                             Salt Per     :
                             Lane Mile       Salt Per Bare
           State               (tons)       Pavement Lane Mile
        Connecticut
        Maine
        Massachusetts
        New York
        Pennsylvania
        Maryland
        Ohio
        Illinois
33
 8
35
19
11
19
25
10
33
20
35
19
34
31
25
19
These  figures indicate that the problems in West Virginia might be
expected to be  less serious than in other snow belt states; and, con-
sequently/  the costs of maintenance and repair may be higher in other
states.
                                   69

-------
      gffljg MODERATE-SEVERE (100 - 80%)
      p5*l LIGHT-MODERATE (20 - 30%)
      I    I NONE-LIGHT (Less than 20%)
            Figure 13 Corrosion of reinforcing steel in highway structures
                      (from Kliethermes, Reference 230)
            Table 6.   Summary of Microeconomic Costs
    Activity
      Estimated
Cost per Square Foot
  Estimcited
Life Expectancy
Visual Inspection
Chloride Detection
Maintenance  Patch

Restoration
Replacement
      Nominal

   Variable  -  $.25

   Variable  -  $.50+


      $9.00

      $15.00
New Techniques:
    Polymer Impregnation     $1.
    Membranes                $1.
    Epoxy  coated steel       $1.
    Latex  modified concrete  $.50
    Wax  in concrete          $1.

Cathodic Protection          $.50+
  One year

  Variable

Few imonths  to  few
years
Up to 15 years

Up to 50 years


Up to 50 years
Up to 15 years
Up to 50 years

      ?

Up to 50 years
                                  70

-------
All figures in the table are to be taken as estimates, and were derived
from the available literature, consultation with highway department
officials, and our judgment as to the probable trend of costs once a
technique becomes, proven (viz. cathodic protection whose costs in large
scale use are largely unknown - but mav be quite low).  The life of a
bridge is taken to be 50 years, in a salt-free environment — thus no
activity could be expected to produce a life expectancy greater than
50 years.

It should be noted that the estimates provided include not only mainten-
ance and repair costs, but also incremental costs of preventive measures
through the improvement of construction techniques for new bridges.  The
technical discussion of bridge-deck repair in Section 4.2.2 reviews
the experimental evidence that polymer impregnation of concrete is quite
cost-effective; given its extreme durability it will probably become
the most inexpensive method of protecting new concrete decks.  The annual
cost of'incorporating'polymer-impregnated concrete in all new bridge
decks constructed in the snow belt can be estimated by multiplying the
number constructed each year by their average size by the cost per square
foot.  Annual construction volume in the snow belt ranges from 1,000 to
1,500 bridge decks, with an average size of about 8,800 square feet
(818 sq. m.)*    At a cost of roughly $1 per square foot, ($ll/sq. m.)
the total cost would be approximately $9 to $13 million.

Adding the incremental cost of bridge-deck construction required to
prevent salt damage to the estimated maintenance costs thus yields a
total direct cost figure for bridge decks alone of approximately $210
million.  Again, it should be emphasized that this estimate is based on
very conservative assumptions.  Projecting these costs into the future
is difficult.  While preventive measures are likely to reduce the need
for maintenance and repair, the exact reduction in the latter costs is
uncertain.  In addition, given the total number of bridge decks and
their maximum life expectancy, it would appear that the current annual
construction volume is insufficient to replace all of the bridge decks
within the time period of 50 years.  Stepping up construction activity
would result in corresponding increases in the costs of prevention.
Based on  these considerations, and the cost estimates derived above, it
is reasonable to assume that the annual direct costs associated with
salt damages to bridge decks will be in the neighborhood of $200 to $250
million annually in the next few years.

This figure refers primarily to bridge decks.  In addition, the relevant
direct costs attributable to salt-induced damages should also include
the costs of necessary repairs because of structural damages.  While these
damages are insufficiently documented for the nation as a whole, specific
 *   According to  Richard Hay  of  the Federal Highway Administration.
                                    71

-------
instances can be cited to provide an impression of the potential magni-
tude of this problem.  For example, damages to the West Side Highway
Viaducts in the Borough of Manhattan in New York City were severe enough
to require rehabilitation efforts at a cost of approximately $96 million,
or almost $50 per square foot  ($4.65/sq. m.) of highway*.  While this
particular example.may be exceptional, it illustrates the possible magni-
tude of additional costs associated with major "damage cases related to salt
use.

5.4.2   Indirect Costs

The direct cost estimates include only expenditures by highway agencies
for special design features on new bridges and the repair of existing
structures to counter the adverse effects of road salting.  Full social
costs would include delays to  motorists during repair, repair costs for
damages to ball joints and front end alignment from travel on uneven
bridge surfaces, and the cost  of accidents which are attributable to
rough bridge deck surfaces., Some of these latter costs, though poten-
tially important, would be exceedingly difficult to measure accurately.
Therefore, the analysis here focuses on the value of lost time.

The discussion of vehicle behavior at sites of traffic obstruction in
a recent OECD report  (260) provides a basis for estimating times loss
during bridge repair.  In the  hypothetical example to follow, a typical
repair of a three lane bridge  deck  (each way) in an area subject to
congestion at rush hour is examined.  A's such it probably represents a
maximum estimate for time loss during bridge repair.  Obstructions such as
bridge repair lower highway capacity.  Studies of freeway traffic in
Los Angeles indicate that the  capacity of a three lane highway that has
been constricted to two lanes  is reduced from a range of 4,000 to over
5,000 vehicles per hour to the lower range of 2,400 to 3,200 vehicles
per hour.  Congestion feeds upon itself; as traffic begins to slow,
drivers will respond by more frequent lane switching and other maneuvers
that only serve to aggravate the situation* .  (260)        '
* The engineering reports  cited deicing salts as one of the major factors
contributing to the structural weakening of the bridge.  See: Hardesty
and Hanover, Consulting Engineers: Reports on the Inspection and Analysis
of the West Side Highway  (Miller Highway).  For the City of New York,
Department of Highways, Contract No. THXM 152E, Capital Project No. HW19.
Four reports October,  1974-May, 1975.  (References 221, 222,. 223, 224).

+  This  example excludes a myriad of technical questions-  Other factors
which affect traffic flow  include: (1)  the length of the obstruction,  (2)
the control of traffic speed at the obstruction,  (3) controlled gaps  in the
flow which may actually increase the capacity of the obstructed section,
and  (4)  the opportunity for using reversible lanes can significantly  reduce
the impact of the obstruction.
                                     72

-------
Figure  14 portrays  the hourly traffic capacity and  demand for inbound
vehicles  and Figure 15 the  cumulative capacity and  demand for this
highway.   Total waiting time  for venicles using this road segment is
given as  the shaded area between the  given  capacity of the system and
cumulative demand on the system.  The delay for traffic  entering at
a given hour is given by the  horizontal  distance between the  cumulative
demand  and cumulative capacity.  The  total  area between  the two curves
may overestimate actual waiting time  to  the extent  that  motorists are
diverted  to uncongested alternative routes.  If motorists'  decisions  to
use alternative routes also produce  congestion on  the alternative routes
the estimate could  conceivably be understated. In  this  example, total
waiting time before the lane  obstruction is 4,000 hours, and  after the
lane restriction about 17,200 vehicle hours.  Valuing  an hour's wait  at
$3.00 per hour provides an estimate of $51,600 per  day.*  Assuming the
repair  requires  50  working days,  and  that repairs to outbound lanes
will require similar delays to motorists, the total cost of delay may be
 estimated as in excess of $5  million.  Although delay  costs of this
magnitude may  be  extreme,  several such instances probably occur in or
 near large metropolitan regions  every year.  Until  better data are  avail-
 able on the actual number of bridges  being repaired and the typical  time
 delays  involved,  no accurate national cost figures  can be reported for
motorist's delays.
                                                    Cumulative Capacity
                                                               2800/houi
Demand

 5,000

 4,000

 3,000

 2,000

 1,000
                                        20
                                        18
                                      •rH

                                      1 16
                                      (Ti
Demand
        Capacity
                        &
                        0)
10

 8

 6
                                       O
                             umulative Capacity
                                       4000/hour/
    Cumulative
    Demand
      AM  6   7   8  9   10   11   12  1P.M.  A.M.6   7   >  9  10 11  12   1P.M.
                 Time of Day                         Time of Day
  .Figure 14.  Hourly Traffic Capacity  Figure 15.  Cumulative Traffic Capacity
              and Demand

  * Economists (see Owen,  "The Value of Commuter Speed," Western Economic
  Journal,  June 1969)  have argued that the costs of delay increase more than
  proportionately with the length of the delay.  The $3.00 figure is an
  approximate average of the costs of short and long delays.
                                       73

-------
 5.4.3   Estimates of Total Costs

 While it is  difficult to  get a firm handle on the relevant cost categories,
 both direct  and indirect,  for evaluating the national costs of salt-related
 damages  to bridge decks,  the available  information is sufficient, to sug-
 gest that society incurs  substantial  costs as a result of bridge deck
 deterioration.   A very conservative estimate of the direct costs of reha-
 bilitative and  preventive measures  associated with this problem places
 the  total national cost at close to $250 million.  The analysis of one
 indirect cost category yields estimates of up to $5 million for a single
 bridge.   Since  nearly 100 thousand  bridges are affected by required repairs,
 even a low probability of occurrence  of such costs attributable to increased
 waiting  times as a result of lane closings for repairs would still yield
 substantial  total costs.   Even if only  one bridge in 2 .thousand  (.05%)
 were similarly  affected,  the total  indirect costs of increased waiting times
 would amount to $250  million.   These  extreme costs are admittedly very
 infrequent.   However, it  is likely  that smaller waiting costs are incurred
 at more  bridges.   An  estimate of $250 million for the indirect costs of
 waiting  therefore is  probably again on  the low side.

 In summary,  the total annual costs  of bridge deck damages related to salt
 use  can  be estimated  to exceed $500 million.

 5.5    COSTS  OF  AUTOMOBILE  CORROSION

 Sufficient evidence has been presented  in Section 4.2.1 to support the
 assertion of a  causal relationship  between deicing salts and:corrosion
 of automobiles.   This corrosion in  turn results in a variety of costs to
 automobile owners.  Four major cost categories can be distinguished:
       •    costs of  protective measures both by manufacturers
             and by owners;

       •    costs of  repairs  required to maintain the ability of the
             automobile to  function  at the same level as without salt-
             induced corrosion;*

       •    losses  in economic value  of the automobile as a result
             of  salt-induced  corrosion; and

       •    costs  of  accidents  attributable to automobile malfunctioning
             associated with salt-induced corrosion.

The first  category presents a number  of difficulties in measuring the
relevant costs.   The main problem is  the attribution of design changes
or other protective measures to the salt problem.   Any measure of costs
in these categories is therefore fraught with considerable uncertainties.
* The relevant costs here refer only to that portion of outlays required
to restore the corrosion damage which actually impairs the level of ser-
vice provided by the automobile.
                                     74

-------
In the interest of reliable cost measures, this category will not be
included as an integral part of the total cost estimate.

A similar reasoning applies to the second cost category.  It is difficult
to assess the degree to which expenditures on repairs are actually required
to restore or maintain the automobile's ability to provide the same level
of services as in a salt-free environment.  Generally, relevant repairs
tend to go beyond the required level.  In addition, expected repair costs
associated with salt-induced corrosion are reflected in the loss of eco-
nomic value of the'automobile.

The third category is the most important one, since it is possible to
attribute depreciation rates to the influence of salt.  Under the general
assumptions of economic theory, the loss in economic value accurately
reflects the expected costs associated with a reduction in the automobile's
ability to provide the desired services.  These expected costs include
direct outlays for restoring at least part of the loss.  While the ideal
conditions assumed in economic analysis (such as perfect information
without uncertainties) are consistently violated in the real world, the
concept of the loss in economic value reflecting expected future costs
(or losses in benefits) is sufficiently broad to cover the full spectrum
of monetary equivalents of the corrosion damage caused by deicing salts.

In fact, the concept is comprehensive enough, to include the likely costs
of accidents, the fourth category of, costs.  Provided the consumer is
able to assess the likelihood of an accident as a result of corrosion
damages to certain components of the automobile, the reduction in econo-
mic value of the car includes the expected costs of such accidents (or in
risk associated with this cost category).   This interpretation is useful,
since it eliminates the need for an estimation of the highly uncertain
costs of accidents attributable to salt-induced corrosion damages.

These considerations determine the approach presented here.  The analysis
first examines the formal framework for expressing depreciation rates as
a function of the use of deicing salts.  This discussion is followed by
an empirical analysis of the relationship on the basis of used car prices
in different Standard Metropolitan Statistical Areas  (SMSAs) of the country.
The section concludes with an assessment of the costs of undercoating and
other preventive or restorative measures.

5.5.1   Depreciation of Automobiles

The analysis of the relationship between original purchase price and
current value of a car (as described by the current market price)  can draw
on established models in capital theory.  Ackerman (268)  has developed
such a model of used car prices.   This model is sketched in Appendix B;
it results in a simple exponential decay expression with a constant
depreciation rate:
                                     75

-------
         (1)

         where P(v)
               P(0)
                 v
                 B
                 a
P(v)/P(0) = Be
or P (v) = P(0)Be
   = the current price of the car
   = the original purchase price of the car (new)
   = age of the car
   = a constant
   = the constant depreciation rate
On the basis of data on prices of cars at age v and their corresponding
original purchase prices, the two unknown coefficients in this expression
B and a — can be estimated by applying ordinary least squares to the
logarithmic form of the depreciation function:
          (2)
 In P(v)  -  In P(0) =  In B  -  av.
The major data source for prices of used cars are the guidelines prepared
by the National Automobile Dealers Association  (NADA) which are published
on a regional basis.  Ackerman  (268) estimated  the coefficients of Equation
 (2) using NADA prices from the July price books for  the period 1956 to 1965
for several makes and two production years  (1956, 1958).  She obtained
the following results for the constant depreciation  rate, a:
                Make

             Chevrolet (1956)
             Ford  (1956)
             Plymouth (1956)
             Chevrolet (1958)
             Ford  (1958)
             Plymouth (1958)
                              Annual
                         Depreciation Rate

                               27.9%
                               29.4%
                               34.2%
                               28.8%
                               29.7%
                               33.2%
 This  model of used-car prices establishes a framework for assessing the
 effects  of external factors on the overall depreciation rate.   This assess-
 ment  is  based on the assumption that the depreciation rate,  a,  in Equations
 (1) and  (2)  is not a constant for a given make and production year, but
 varies by geographical region in response to environmental conditions (such
 as climate or the use of deicing salts), use and maintenance practices for
 the car, and prevailing preferences and tastes.   Observations on these
                                      76

-------
factors require a much smaller level of aggregation than implicit in the
NADA regions.  The unit of observation used in the analysis here is therefore
a city; the discussion below describes sample selection and data-gathering
procedures, following a review of the likely impact of different factors
on automobile depreciation.

       Environmental Factors:  Characteristics of the physical environ-
ment in~which the car is operated directly affect corrosion and thereby
the loss in economic value.  These characteristics include ambient tem-
perature, atmospheric humidity, sulfur dioxide concentration in the
atmosphere, and other pollutants that are known to contribute to corro-
sion.  Similarly important is the incidence of cases in which automobiles
are exposed to moisture, such as measured by rainfall or snowfall.

Finally, an important factor concerns the characteristics of roads on which
the cars are driven.  These characteristics may include elements such as
road surface and road dirt.  Most road dirt, for example, clings to parts
of the automobile body, retains moisture and thereby.fosters the process of
corrosion.  Similarly, loose aggregate may result in scratches in the body
finish, making it vulnerable to corrosion.  Unfortunately, this factor is
almost impossible to measure except in an experimental situation.  The
most important road characteristic, at least for the purpose of the inves-
tigation here, is the incidence and intensity of deicing salts on the
road surface.

       Use and Maintenance of Cars:  The depreciation of a given automobile
depends to a large extent on its expected useful life, which in turn
reflects its past use as well as any maintenance efforts by the owner.
One important factor is the mileage the car has been driven.  Another
factor is the frequency and  thoroughness of washing the car, which may
delay  corrosion by eliminating pockets of dirt and moisture as well as
removing salt from the body  or structural parts of the automobile.

Again, many  of the relevant  aspects of use and maintenance cannot be
measured at  an aggregate level with any degree of accuracy.  For example,
there  are  few if any data  on the frequency and thoroughness with which
a car  is being washed.  Similarly, the extent of garaging —' which may
modify the importance of ambient temperature as  a determinant of corro-
sion —  is unknown on a large-scale basis.

        Teistes and Preferences;  It is entirely possible that differences
in depreciation rates among  cities reflect little more than interregional
differences  in terms of preferences  for new vs.  used  cars.  For example,
 areas  in which public transportation provides an efficient alternative
 to the private automobile,  two-car families may  be  rare.  Alternatively,
 in areas  in  which  a  second car is  owned by many  families, the structure of
 tastes and preferences may be  such that the demand  for used  cars  is strong
 and used car markets  are  active.
                                       77

-------
No reliable  indicators  of such regional  differences in tastes and pre-
ferences  exist.  While  the potential  importance of these  factors in deter-
mining  the rate  of depreciation of  cars  is  recognized, the analysis here
therefore does not attempt to  isolate this  particular factor.

        Specification of the Regression Equation;  The influence of the
type of factors  examined in the preceding paragraphs on the depreciation
rate for  automobiles has been  examined through multiple regression analysis
designed  to  test the existence of any functional relationships of the
form:

        Depreciation Rate = f(Environmental  Factors, Use of Maintenance,
                             Tastes and  Preferences)         :

Primarily, for reasons  of simplicity,  the linear additive form of this
functional relationship  was examined to isolate the net  effects of deicing
salts.  The  specification of a linear relationship between the depreciation
rate and  independent variables clearly is questionable for certain var-
iables, as illustrated  by means of  an example, under the  simplifying
assumption that  depreciation is directly related to corrosion of struc-
tural parts  or the body of the car.   It  is  known that the rate of chem-
ical reation (i.e.,  corrosion  of steel)  is  temperature dependent: the
rate of reaction doubles for every  10°C  increase in ambient temperature—
clearly a non-linear relationship.  The  linear relationship hypothesized
in the  regression  model may not be  a  close  approximation, even over the
relatively narrow  range of temperatures  that are encountered.!  However,
the specification  error may be relatively small compared  to the inherent
measurement  error.   It  is  extremely difficult to determine the appropriate
temperature  measurement to use for  assessing its impact on corrosion.  Is
it the  temperature of a heated garage  in winter (a major  factor contri-
buting  to corrosion), the  average ambient winter temperature, or some
annual mean? The  actual effect of  temperature is therefore difficult
to determine.                                                ;

The relationship for other variables such as salting intensity is probably
specified in the theoretically correct form.  Tests discussed earlier by
the APWA  and NACE  indicate that the corrosion rate increases approximately
linearly  in  the range of salt  concentrations encountered by automobiles in
typical winter driving  conditions.  Overall, given the current understanding
of the determinants  of  corrosion and their  effects on automobile deprecia-
tion, no  alternative specification of  the equation used in the regression
analysis  appears more appropriate than the  linear one.

5.5.2   Data Collection  for Empirical  Analysis

As  already mentioned above, the data on used car prices available through
NADA price books are at too aggregate  a level to be useful in tessting
the effects of the three types of factors distinguished above.   The anal-
ysis here, therefore, requires estimates of the depreciation rates  for the
same make of vehicle in different environments to allow for the use of
characteristics of these environments to "explain"  the  variation,,  if any,
                                     78

-------
in the rates.  A suitable definition of environment refers to cities in
the continental U.S.

Estimating decay rates, in the same way as Ackerman (268), for different
cities is complicated by problems of data availability.  This approach
would require sufficiently accurate statistics on used car prices for
a relatively long period of time, such as ten years, for each city.  Such
statistics can be obtained from newspaper advertisements, but the labor
requirements for searching newspapers from an adequate number of cities
over such a time period are prohibitive.  However, given Ackerman"s findings,
the data requirements for the analysis here can be reduced substantially.
Since these findings suggest that the exponential depreciation model
with constant rates fits reasonably well, representative depreciation
rates can be calculated on the basis of new car prices and a single obser-
vation on a used car price.*

The procedure followed to estimate decay rates was to obtain several
price observations  (30 on the average)  on each of the three makes of used
cars in 44 metropolitan regions, and to calculate the rate of deprecia-
tion for each observation required to yield the used-car price.  For each
city, a representative depreciation rate was calculated as the simple
arithmetic average for the respective observations.  These estimates are
shown in Table 7 .  All of the estimated rates are lower than those
reported by Ackerman and shown above.  This may be partially due to the
composition of the sample of car makes: Chevrolet Bel Air, Chevrolet
Impala, and Volkswagen.  The inclusion of Volkswagens, which depreciate
at unusually low rates, lowers the overall average.  In addition, there
is the possibility that estimates of new car prices are somewhat inaccu-
rate.  However, neither of these factors should affect the estimated
variation in depreciation rates across cities; in other words, there is
no reason to believe that such measurement errors would introduce any
bias into the sample.

Table 7 presents depreciation rates by broad categories of exposure to
deicing salts.  There is a fairly consistent trend across the three
categories distinguished: depreciation rates rise as the intensity of
salt use increases.  However, this trend should not be overemphasized:
the measured depreciation rates may be inaccurate, or other factors that
are actually responsible for interregional variations happen to be cor-
related with salt use.
* New car prices were estimated as 90% of suggested list price  plus
dealer preparation costs and transportation charges.  Adjustments for
optional items  (e.g., air conditioning) were made, if advertised.
                                      79

-------
                               Table 7                       ;

             Estimated Depreciation Rates for Selected Cities
Salt more than 25
tons per lane mile
Salt between 5 and
25 tons per lane mile
       Salt less than 5
       tons per lane mile
Hartford, Conn.    23.5
Chicago, 111.      24.2
Portland, Me.      25.1
Baltimore, Md.     23.3
Boston, Mass.      24.1
Springfield, Mass. 23.5
Detroit, Mich.     25.1
St. Paul, Minn.    25.2
Concord, N.H.      26.9
Syracuse, N.Y.     26.1
Cincinnati, Ohio   22.1
Cleveland, Ohio    23.4
Philadelphia, Pa.  22.9
Providence, R.I.   23.6
Pittsburgh, Pa.    25.5
Salt Lake City, Ut.23.0
Burlington, Vt.    26.6
Milwaukee, Wise.   22.7
    Mean           24.3
Wilmington, Del.
Indianapolis, Ind.
Des Moines, la.
Augusta, Me.
St. Louis, Mo.
Omaha, Neb.
Newark, N.J.
Oklahoma City, Oh.
Memphis, Tenn.
Richmond, Va.
Laramie, Wyo.
22.1
22.1
21.2
26.8
22.0
21.3
2.18
22.4
20.3
21.5
22.6
Phoenix, Ariz.
Los Angeles, Cal.
Denver, Col.
Tampa,' Fla.
Atlanta, OSa.
Gt. Falls,. Mont.
Reno, Nev.,
Albuquerque, NM.
Portland, Ore.
Charles ton, S.C.
Dallas, Tex.
Seattle, Wash.
19 :-4
19.8
21.5
20.
20.
20.
21.8
19.4
19.
20.
21.
.1
.2
.1
.5
.7
.5
                                             21.4
            Mean
22.2
        Mean
20.5
                                      80

-------
the NADA regions and compared to.the NADA price guidelines.   Within
regions considerable variations in depreciation rates were observed:
for example, within the New England region, Providence, Rhode Island
showed a composite depreciation rate of 23.6%, while the corresponding
rate for Concord, New Hampshire was 26.9%.  .Average prices for regions,
though, were much closer to the NADA figures; in each case,  the two
prices were within 10%, with the typical difference being much less.
Overall the newspaper prices averaged approximately 2% less than prices
in the NADA guides.  Since the actual prices for cars advertised in
newspapers are likely to lie below the stated asking prices, the compar-
ison indicates that the two markets differ substantially.  Differences
may be attributable to quality differences in the cars offered for sale,
or to better resale preparation by used-car dealers.

These considerations established a set of observations for the dependent
variable in the regression equation.  As the discussion of the potential
range of independent variables above indicates, within each of the three
categories of factors distinguished, several measures can be used to
describe the elements influencing regional variations in depreciation
rates.  The following measures have been selected for the analysis reflec-
ting the principal emphasis on the importance of environmental variables
as determinants of corrosion.

5.5.3   Environmental Conditions^

State salt refers to the number of tons of salt applied per lane mile of
bare pavement on state highways for the winter of 1969-1970.   (Bare pave-
ment is the highway engineer's term for pavement that is kept free of ice
and snow year round through plowing and liberal application of deicing
chemicals.)  In cases in which salt usage for this winter differed sub-
stantially from that for the winter of 1966-1967 (the other year for which
these data were compiled by the Salt Institute), the mean of the two
figures was used.

City salt refers to the number of tons of salt applied per lane mile of
bare pavement on city highways during the winter of 1969-1970.  Cases
with substantial differences between 1969-1970 and 1966-1967 were handled
in the same way as described for state salt.

Snow fall has been measured in inches for the winter of 1969-1970 for
each  city.   If  this value  differed by more  than 25%  from  normal  levels,
the average snowfall for the three winters  (1966-1967,  1969-1970, and
1970-1971)  was  used.

Temperature was  measured as the mean ambient January reading  for each
city  in degrees  Centigrade.

Humidity/rainfall; humidity statistics proved difficult to obtain, and
consequently rainfall  in inches per year  was substituted  for  humidity.
                                    81

-------
Proximity to ocean was included as a dummy  (0/1) variable in the
regression analysis.

Sanding intensity was measured as tons of sand applied per mile of high-
way in each state.

Air pollution was measured in the regression by a single variable, the
annual mean concentration of sulfur dioxide in ug/m3.

Use and Maintenance

As already discussed above, the measurement of many of the relevant
aspects of use and maintenance of cars on a non-experimental basis is
extremely difficult, if not impossible.  The analysis therefore used
only one measure, the average number of miles  (in thousands) traveled
by a vehicle in each of the states.  Unfortunately, vehicle mileage was
not available for the cars offered for sale.               i
Tastes and Preferences                                     :

The discussion above indicates that tastes and preferences themselves
are almost impossible to measure in a way that would yield meaningful
descriptors for the analysis here.  In an attempt to include these
possibly important characteristics, income per capita.and vehicles per
capita were used in the regression as imperfect proxies of 'the determin-
ants mentioned above.

5.5.4   Regression Results

Given the limited understanding of the possible functional relationships
between corrosion and car values, the corrosion and environmental factors,
the regression equation was tested in its simplest, i.e., linear form,
as discussed above.  The approach was largely empirical, that is, all
variables assumed to influence depreciation rates were used in different
specifications as explanatory variables in the regression analysis.   The
following functional form showed the best performance:      i.
          DEPRECIATION RATE = 15.7 + .038 STATE SALT + .019 CITY SALT
                                     (2.01)            (3.03)

                                   + .029 SNOW + .170 MILES
                                  .   (3.67)      (1.48)
The figures in parentheses under the regression coefficients refer to
the t-statistics of the coefficients, a measure of statistical
                                    82

-------
significance.*  The multiple correlation coefficients for this equation
was .79, which implies that the variation of the four independent
variables "explains" 79% of the variation of the dependent variable
across the 41 metropolitan areas finally used in the regression analysis.+
The t-statistics shown indicate that both 'city salt and snow have coef-
ficients that are significantly different from zero at the 99% confidence
level; the significance level for state salt is 95%, while the coeffic-
ient of miles traveled is significantly different from zero only at the
90% confidence level.  All coefficients have the expected sign.

None of the other explanatory variables used in the series of regression
analysis runs showed any systematic relationship to the depreciation
rate.   A partial exception concerns the two indicators of tastes and pre-
ferences, income per capita and vehicles per capita.  When either of these
variables was included in the entire regression, the coefficients were
not significantly different from zero.  When used with the salting intensity
and snowfall variables separately, the coefficients of both income per
capita and vehicles per capita were significant, income havina a negative
sign  (depreciation being lower with higher per capita incomes) and vehicles
per capita having a positive sign  (more used cars on the markets resulting
in lower prices).  The most likely explanation for these differing results
is that income per capita is spuriously correlated with snowfall and salting.
The North-Central, Mid-Atlantic and New England regions all have above
average income and also have greater than average snowfall and use corres-
pondingly more salt.

The reliability of the estimated coefficients for the salt use variables
in the regression equation shown may be questioned on several grounds.
First, some positive collinearity between salt use and snowfall is
possible, which may imply that part of the variation of the depreciation
rate  associated with variations in snowfall is erroneously attributed
to salt use.  However, the relatively high t-statistics for the respec-
tive  coefficients and the comparatively low correlation between salt and
snowfall  (.64 or less) suggest that this problem is not severe*. Even•-
so, it is difficult to answer this question with precision.

Second, relationships between environmental factors and automobile
depreciation are confounded by the fact that cars are rarely exposed to
one environment alone.  Exposure of automobiles to different environments
as the owners move or vacation is  likely to reduce the variation in
measured depreciation rates as compared to cases in which cars are less
*  Generally,  t-statistics  greater  than  2.0  indicate that the regression
coefficient is  significantly  different  from zero,  i.e., that there  exists
a  relationship  between the dependent  and  independent variables.

+  Because of  missing  observations, three  of the  cases had  to be excluded
from the analysis.

$   This comparatively low  correlation may reflect  the fact that many mid-
west and western communities  rely  on  plowing and sanding for winter high-
way maintenance.
                                      83

-------
mobile.  As a result, the regression coefficients estimated above may
seriously understate the true relationships between independent and
the dependent variables.

Third, the years chosen for the measurement of snowfall and salt use
may not be representative.  Consequently, fairly large errors in the
measurement of the independent variables may be expected.  Such errors
can be shown to produce regression coefficients which are biased toward
zero.  In this case, the regression coefficients again would understate
the true relationship.

Fourth, the analysis does not account for more recent improvements of
design and corrosion resistance by manufacturers.  Since most recent
vintage automobiles were not included in the study, the estimates may
overstate both the depreciation rates and their dependence on snowfall
and salt use.

Given the data situation — as well as the level of theoretical under-
standing of the problems involved — the net effect of these factors on
the reliability of the regression estimates cannot be determined with
precision.  All that can be done is to acknowledge these issues and take
them into consideration in interpreting the findings reported here.

5.5.5   Estimation of Total Costs of Automobile Depreciation

The results of the regression analysis can be used to calculate the total
economic costs of the incremental depreciation of automobiles attributable
to the use of highway deicing salts.  The procedure used for this purpose
is straightforward: we need to determine the value of the stock of auto-
mobiles in various environments and multiply the stock value (by vintage)
by the incremental depreciation attributable to salt use.  Since adequate
data on the composition of the total automobile stock by region and vintage
are not available, data on the proportion of automobiles of each vintage
still remaining registered (from R.L. Polk & Co'.) have been used to
translate total registrations into a total dollar value; Appendix B
describes this procedure in greater detail.

Table 8  shows the results of these calculations.  The first column con-
tains the number of registrations by state, the next two columns show
salt-use intensity, the fourth column displays the incremental deprecia-
tion computed on the basis of the regression estimates, and column 5 the
incremental loss in the economic value of automobiles attributable to
the effects of the use of deicing salts.  This estimate is based on an
average value per car of $1,500, as derived in Appendix B.

The total yearly national cost of the accelerated depreciation of auto-
mobiles due to the effects of deicing salts on corrosion is .estimated at
$1.4 billion, or $14 per car — which corresponds roughly to 1% of the
value of the average automobile.  Since this measure is an overall average
it is clear that the relative economic loss attributable to accelerated
                                     84

-------
Table 8
uost or AutomoDiJLe ue
State
AL
AK
AZ
AR
CA
CO
CT
DE
FL
GA
HI
ID
IL
IN
IA
KS
KY
LA
ME
MD
MA
MI
MN
MS
MO
MT
NE
Estimated 1973
Registration
(in thousands)
1,837
109
1,052
743
11,007
1,359
1,771
284
4,358
2,538
413
412
5,095
2,332
1,480
1,217
1,613
1,614
462
1,938
2,653
4,414
Ii959
963
2,077
412
813
State Salt
X .038



.1
1
1.5
33
12



1
19
12
8.8
4.6
.12

20
30.9
35
29
11

15,1
.1
1.4
City Salt
X .019



2
1
1
40
25



.5
60
22
6
7
6

70
33
50
100
45

25
1
13
preciation
Depreciation
X 100



.042
.057
.076
2.014
.931


,
.048
1.862
.874
.448
.308
.570

2.090.
1.801
2.280
3.002
1.273

1.049
.023
.300

Col. 1
X 4



31
627
103
3,567
264



20
9,487
2,038
663
406
919

965
3,488
6,048
13,242
2,494

2,178
9
244

Loss in Value
X 1500, X 10
(in millions)



.46
9.41
1.54
53.51
3.96



.30
142.31
30.57
9.95
6.09
13.79

14.48
52.32
90.72
198.63
37.41

32.67
.14
3.66
    85

-------
Table 8 (Continued)
State
NV
NH
NJ
NM
NY
NC
ND
OH
OK
OR
PA
RI
SC
SD
TN
TX
UT
VT
VA
WA
W
WI
WY
DC

Estimated 1973
Registration
(in thousands)
318
393
3,686
530
6,360
2,702
304
5,567
1,377
1,328
5,730
500
1,286
323
1,919
5,808
565
223
2,329
1,786
704
1,871
183
222
101,237
State Salt
X .038
.3
39
6
1
18.7
5
.4
25.5
.5
.1
34
35

.2
4.1
.7
39
44
10
3
25
15.8
.2
27

City Salt
X .019
.3
120
24
1
50
3
1
50
6
1
30
25

2
• 1

8
30
20
2
20
50
8
15

Depreciation
X 100
.068
3.762
.684
.057
'1.661
.247
.034
1.953
.133
.023
1.862
1.805

.045
.175
.027
1.634
2.242
.760
.152
1.330
1.550
.60
1.311
.917
Col. 1
X 4.
22
1,478
2,521
30
10,558
667
10
10,872
183
31
10,669
903

15
336
157
923
500
1,770
272
936
2,900
29
304
92,879
Loss in Value
X 1500, X 10
(in millions)
.33
22.17
37.82
.45
158.37
10.01
.15
163.08
2.75
.47
160.04
13.55

.23
5.04
2.36
13.85
7.50
26.55
4.08
14.04
43.50
.43
4.56
1.392
Billion
                                   86

-------
automobile corrosion is substantially higher in regions affected by
deicing salts.  For example, for Massachusetts the estimate per automo-
bile is over $34, or more than 2% of the value of the average car.
It can therefore be concluded that the average annual loss attributable
to the use of deicing salts varies between 1% and 2% of the value of the
automobile.

In interpreting these figures, it should be remembered that the estimates
obtained are based on the most conservative set of assumptions, as dis-
cussed above.  For example, the estimated costs do not include additional
expenditures on maintenance (such as more frequent trips to the car wash)
or repair attributable to salt damage.  Particularly the expenditures on
undercoating would constitute a sizeable additional cost,* which is at
least partially related to an attempt to reduce the effects of deicing
salts. ' Cost data on the Ziebart rust-proof ing process may be used to
illustrate this aspect.

The Ziebart technique involves the application of a soft wax to steel sur-
faces in order to deny access to moisture, dirt, salts and soluble atmos-
pheric pollutants.  The present cost of this  treatment ranges from $120  to
$130, depending on the size and complexity of the car, with $130 a typical
cost figure.  Approximately 1.5 million automobiles have been treated
by Ziebart since its  incorporation.         ,

Assume that the value of a  car operated under ideal conditions deprecia-
tes at a constant exponential rate of 25% per year.  The calculations
in Appendix  B show that Ziebart treatment then becomes economically justi-
fiable if  it  prevents additional depreciation in  the range of  1%  to 1.5%
per year  (depending on the  discount rate used).   Since 1.5 million car
owners have found it  appropriate to pay for  this  treatment, it can be
concluded  that the incremental depreciation  estimated  above and presented
in Table  6 is approximately in the correct range.

The costs  of  losses in economic value of passenger cars must be comple-
mented by  a rough estimate  of the costs to trucks and buses.  Although
the present  study has attempted to secure sufficient data  for  a statis-
tical analysis of these  costs, the data obtained  provide little more
than guidance for a relatively crude  assessment.  Based on information
from truck fleet owners,  incremental  depreciation of buses and trucks as
a result  of  corrosion is minimal, primarily  because of greater efforts
in terms  of  maintenance  and treatments.  The annual costs  per  vehicle
have been estimated at $30  on the  average on the  basis of  discussions with
truck  fleet  owners  and managers.  For the  23,000,000 buses and trucks
registered nationwide,  the total annual  costs of  preventing  salt-related
 corrosion damage would therefore be $690 million.
 *  This cost is not necessarily an alternative to accelerated deprecia-
 tion since the observed differences in depreciation rates occur in spite
 of differences in the relative emphasis on undercoating in different
 environments.
                                     87

-------
Under very conservative assumptions, the total annual cost ;of deicing
salt use to owners of motor vehicles therefore is estimated here as being
in excess of $2 billion.

5.6   OTHER DAMAGES

The review of damages attributed,to deicing salts in the preceding sec-
tions has illustrated the broad variety by which salt runoff may alter
natural environmental conditions, thereby initiating or aiding processes
that result in  real economic losses.  By entering both the soil and
the atmosphere, salt is contributing to a change in general environmental
characteristics, primarily with respect to the ion balance., which affects
patterns of corrosion and deterioration of materials exposed to these
conditions.  Consequently, damages that have been attributed to the use
of deicing salts, have been noted in areas other than those discussed in
the preceding sections.  The available evidence on such "other" damages
of course, is limited to reports on a few instances.  However, a brief
review of this evidence suggests that the potential effects of deicing
salts on underground cables and electric utility lines may be substantial
on a national scale.

One of the best-documented instances of salt-related damage to underground
power transmission lines is the case of Con Edison's facilities in. New
York City.  This company maintains in New York City the largest system of
underground electric facilities in the world.  The winters.of 1972-73 and
1973-74 offered a striking contrast in terms of salt applications and in
terms of resulting damages to this underground cable system.  The winter
of 1972-73 was comparatively mild, without much snow.  The ;city used very
little salt that year, about 20,000 tons, most of which was applied to
bridges, ramps and critical intersections.  In contrast, the winter of
1973-74 was characterized by two heavy snow storms leading to intensive
salting; the city used about 120,000 tons that winter.     :

The effects of salt runoff on underground cables become  evident almost
immediately after application.  These effects continue for two to three
months as the salt brine is washed through the underground system.  As
a result, secondary cables (generally rubber-insulated and carrying 120
volts) develop short circuits resulting in fires.  According to data
furnished by Con Edison, there were approximately 1,400 more manhole
fires in the winter of 1973-74 than in the preceding winter.  These
additional manhole fires necessitated extensive repairs and the replace-
ment of almost 1,000 sections of secondary cable at a total cost of
$4,000,000.  In addition, there is evidence that the primary feeders
(cables operating at 13,000 and 27,000 volts)  are also affected by salt
runoff from city streets.  Since these cables are generally better insul-
ated and protected, these effects develop more slowly.

In total, the company estimates that the salt spread on the streets of
New York City resulted in additional expenditures by Con Edison in
excess of $5,000,000 for the winter of 1973-74.  This is a direct cost;
added to it should of course be the costs of power outages to consumers,
which are unknown.  (The company has been lobbying for the adoption of
other substances, such as magnesium sulphate,  to replace salt at least
on an experimental basis).

                                    88

-------
While this example constitutes an extreme case, it does suggest that
the cost of damages to power transmission lines underground may be sub-
stantial on a national scale.  In this particular case, the cost to Con
Edison exceeded direct expenditures on the salt and its application by
the city.  Since these estimates do not include indirect costs to con-
sumers nor damages to above-ground power transmission lines, it is rea-
sonable to assume that the total national cost of these damages is at
least double the cost for New York City, or $10 million a year.


5.7   THE DIRECT COSTS OF SALT APPLICATION

Before providing an estimate of the total costs of deicing salt use,
it is necessary to estimate the actual costs to users of salt applied
for snow and ice control.  As mentioned above, salt use varies consider-
ably from one winter to  the next in response to snow and ice conditions.
Therefore, the calculation of the annual direct costs of salt applica-
tion refers to the annual average.   (The annual figure must be an esti-
mate of an average since supply conditions and transportation costs
lead to sizeable variations in the price per ton of salt.)

Available data  (307) suggest that the cost per ton of sodium chloride
to users lies somewhere  in the $10 - $20 range; the corresponding cost
figure for calcium chloride is $30 - $35 per ton.  In addition to these
costs,   the user also must account for the cost of application, which
is about $5 - $10 per ton.  Since the present  annual salt use at the
national level is approximately 9 million tons, the total annual costs
can be estimated as  about  $200. million.


5.8   SUMMARY OF COSTS                                                ,

The  analysis in this section  indicates  that  the actual  costs of using
salts for highway  snow  and ice control  actually exceeds the direct  costs
of purchase and application by an order of magnitude.   To recapitulate,
the  costs of the  contamination of water supplies have been  estimated
at $150 million;  those  for vegetation  at possibly  $50 million,  for  cars
at $2 billion,  for bridge  decks  at  $500 million, and  for utilities  as
more than $10  million.   Together with  the  cost of  purchase  and  appli-
 cation,  the use of deicing salts may cost  the  nation  close  to  $3.0
billion.

The major  share  of this cost has been  estimated  for accelerated damages
 to vehicles,  a case  for which available data allowed  for a  direct appli-
 cation of  the  general cost estimation  model.   While it is somewhat  spec-
 ulative, it is reasonable  to assume that other costs  are likely to  be
 higher.   Howeverf  present data limitations  do not allow for the explora-
 tion of the full range  of  these  costs.
                                    89

-------
Since the available data allow only for illustrative estimates of the
costs associated with different damage categories, a reasonable break-
down into direct and indirect costs to society and individuals is
difficult.  Since these breakdowns depend on institutional arrangements
(cost sharing between society and individuals for certain damages)  and
actual practice (complete restoration may turn an indirect cost into
a direct cost), on which only few observations exist, the best conclu-
sions possible is that the major share of the cost is borne by the
automobile owners (who, of course, also enjoy any benefits of bare pave-
ment in the middle of winter).  The remaining $1 billion are approxi-
mately evenly divided between individuals and society.
                                   90

-------
r
                                         SECTION 6
                                 BENEFITS OF ROM) SALTING  -

         There are three benefits which have been ascribed to the use of salt
         for snow and ice removal: savings in terms of dollars, lives (safety),
         and time.  The dollar savings is in terms of producing bare pavement
         in a given time under a constraint of a limited highway budget.  As
         demonstrated in Section 5, the savings in snow removal from salt use
         cost that should be considered; indirect costs resulting from salt use
         are much higher than savings in snow removal costs.   Consequently in
         terms of total direct dollar savings, (excluding safety and time savings
         for the moment), heavy salt use does not provide a cost savings, but
         instead incurs a net cost, and is therefore not a benefit.

         On the other hand, salt  is beneficial to the extent to which it increases
         safety and  time savings.  The  relationship between salt use and these two
         factors  is  highly complex, especially with regard to  safety.  It is not
         within the  scope of  this project to perform an in-depth analysis of the
         functional  relationship.  However, it is appropriate  to take a brief
         look at  the work that has been done in these areas.
          i.l
                SALT AND SAFETY
         The extent to which alternative winter maintenance policies affect highway
         safety is not established by the direct comparison of accident rates with
         maintenance policies unless driver behavior is explicitly incorporated as
         a parameter of the analysis.  Although one would expect considerable re-
         search to have been directed toward understanding situations which involve
         the risk of injury and death, surprisingly little is actually known.  ^Human
         behavior under conditions of financial uncertainty has a rich theoretical
         and applied literature, but such models are largely inappropriate for the
         analysis of accident  risk, and  attempts to model human behavior  in sit-
         uations  involving the  risk of life  or limb have not been very successful.
         The existing  evidence  for a connection between safety and alternative
         winter maintenance policies is  both meager and inconsistent.

          It is often tacitly assumed that deicing  salts improve driving conditions.
         Courts,  in assessing  liability  for  single-vehicle winter accidents, have
          found highway department officials  negligent  for not applying enough
          salt  to  provide  an acceptable level of  safety for motorists.  Also, the
          assumed causal relationships  between deicing salts  and highway  safety is
          a major rationale offered by highway department officials  for the twenty-
          fold increase in the annual use of salts for highway deicing since 1950.
                                               91

-------
There is no question that salt can result in an increase in' the coef-
ficient of friction between the tire and road in most cases.  Experi-
ments have verified that under proper temperature conditions* the coef-
ficient of friction for a snow covered pavement can be increased by the
application of deicing salts  (.05 kg. per square meter raises the coef-
ficient of friction from 2.5 to over .40).  (252)  (In the same study
sand, even when applied at ten times the rate, resulted in only a slight
increase in -the coefficient of friction on snow-covered pavement).

Three studies contain information which support the belief that deicing
salts reduce highway accident rates during the winter months.  One study
was conducted by the city of Ann Arbor, Michigan. (258)  In 1967, the
last year before the use of salt for deicing became general practice in
Ann Arbor, 315 accidents were reported; the accident toll fell to 196
and 186 during the next two years.  However, because no informcition is
available as to the number of winter storms, or other measures of severity
of the winters, this data alone does not provide conclusive evidence.

The second study was done by the American Public Works Association (APWA)
in Chicago during the winter of 1963-1964.  (253)  The APWA study contains
numerous statistical tabulations of accident reports; for our purposes
the most illuminating is the proportion of accidents which occurred on
major and local streets under normal and adverse conditions.  During
periods of normal weather (dry roads), four-fifths of Chicago's winter
highway accidents occurred on major roads.  This percentage1 fell to two-
thirds during periods when city-wide driving conditions were adversely
affected by snow and ice, suggesting that winter maintenance, which is
directed toward major streets, does improve highway safety.  Although
the data suggest that Chicago's chosen policy of maintenance, which relies
heavily on salt for deicing, is effective, the accident reduction may be
more dependent upon prompt plowing of major streets than it is on the use
of salts for deicing.

The third study consisted of a survey conducted on salt use and effects
in 116 U.S. cities during 1971-1972  (116 responses out of 504 requests
(287).  One of the findings of this study was given wide publicity and
acclaim by salting proponents: "Salt deicing cuts accidents by 75%
according to new 116-city survey."   (259)  However this statistic was
based on responses from only 14 cities which were able to give a per-
centage breakdown of accidents in response to the question: "From these
accident records, how many occurred on snow and ice-covered pavements
against streets treated with deicing materials?"  Furthermore, in response
* That is, in the temperature range in which salt melts snow and ice
above -9°C for NaCl.
                                    92

-------
to the question, "Do your accident records show a relationship between
weather and street conditions and damage to vehicles and/or personal
injuries?", 42.2% of cities responded "yes", 40.6% responded "no", and
17.2% did not respond.

While the results of the study may be seriously questioned on the basis
of the response sample, there are other serious research problems.  First,
the responses should be weighted by the percent of the salt treated areas
in each city.  Second, there was no backup in terms of snowfall.  Third,
the seriousness of accidents was unknown.  Fourth, the extent of salt use
on different types of streets was unknown.  Fifth, the basis for informa-
tion  (accident records) is questionable, and probably not comparable
between cities.  Very honestly, all of these factors make the findings
useless.

However, other studies have noted a potentially serious effect from the
application of salt:  invisible wetness.  Salt in solution on a road has
the effect of temporarily or indefinitely prolonging the drying of the
surface, thus lowering tire friction.  This situation is particularly
dangerous because the road may appear dry.  The greater the concentra-
tion of the salt solution, the longer the drying time.  Higher air humi-
dity will cause the salt to have a greater effect in delaying the drying
rate.   (254)  In addition, under very low temperatures (-27°C for NaCl and
-51°C for CaCl2)r too much salt decreases the melting rate and in some
instances may assist the formation of ice (2).  While these adverse con-
ditions may occur only a very small fraction of the time, they still must
be considered as a negative effect of salt.  In a study of accidents in
rural and urban cities within Oakland County, Michigan, it was found that
as the use of salt increased, the percentage of accidents occurring under
icy conditions decreased  (249).  This is to be-expected since salt will
reduce the frequency of icy conditions.  However, it does not necessarily
prove that salts increase safety,  for the same study also found that the
total number of winter accidents increased with increased use of salt.
This apparent contradiction might be attributed to an increase in traffic
as driving conditions improved, though this tentative conclusion remains
unchecked because no statistics were recorded on vehicle density.  The
researchers commented that salting may create a false sense of security
in many drivers  (249).  While this statement remains unproved, it is im-
portant to point out some analogous findings.

Two economists  (Peltzman and Anderson) have noted that an improvement in
safety, either in vehicles  (automobile seat belts in the Peltzman study)
or in highway conditions  (Anderson), could elicit an increase in motorist's
speed sufficient to. render indeterminant the impact of safety improve-
ments on accident rates  (248, 257).  Under hazardous winter conditions
drivers do slow down, probably enough so that their perceived risk of
injury is the same as under normal driving conditions (risk of minor acci-
dents may rise or stay the same).  Whether the perceived risk is the same
as the actual risk is unknown.  However, it is reported that an Ottawa,
Canada consulting firm found from accident records that accidents occur-
ring on icy roads are generally property damage, while accidents occurring
                                    93

-------
on bare   (dry or wet) pavement, during the winter are more likely to
involve personal injury.  (53)

Substantial research of the relationship between salt and safety is a
necessity.  While salt does serve to increase friction under proper use
on a stretch of highway, this is not the only factor which determines
accident rates.  Research must consider continuity of conditions along
a roadway, speed, and most of all, driver behavior.  Such research will
be extremely difficult indeed because determination of risk taking under
varying driving conditions is a difficult (if not impossible) task.
However, until such research is performed, it is false to assume that salt
and safety are synonomous.
6.2
TIME SAVINGS
Anyone who has driven under snow and ice conditions knows that his progress
is slowed, especially during rush hour.  There have been scattered esti-
mates of the cost of lost time  (10), but there has been no major effort
to assess the true value of the lost time.  While the costs1 may be high,
a certain amount of care must be taken in developing the figures.  For
example, it is false to suggest that a one hour delay for all persons in
a city will result in a loss of one-eighth'of the economic activity for
that day.  While there may be a one hour loss because of a shutdown of a
continuous industrial process, there is probably little if any loss in
terms of shopping expenditures.  Shoppers will simply defer their errands
to a later time with the result that there will be only a short-term loss
to the stores.  As a result of a survey on the impact of snowfall on man-
ufacturing and retail activities in selected cities in the U.S.,, one
study reported that:

       "Probably the most significant and best supported fact to
       emerge from the survey was the relatively small problem that
       snow appeared to pose for all types of manufacturing industry.
       Few, if any, of the firms interviewed felt seriously threatened
       by snow and the majority took only the most rudimentary pre-
       cautions to ensure that operations were not disrupted.  Also
       there was no conclusive evidence to support the contention that
       attitudes or actions were significantly altered by the cictual
       snow environment"  (Ref. 59, p. 110)

While this attitude may certainly be a result of the presently efficient
snow removal procedures, it does seem to imply that a slightly increased
delay in clearance of snow and ice would not produce disastrous results.
Nevertheless, the question of actual cost of lost time from snowstorms
is still a problem very open to research.

Better planning for the possibility of hazardous snowstorms; would
probably help to reduce business losses.
                                    94

-------
                           BIBLIOGRAPHY
Sections

1.     General Environmental
2.     Costs of Snow and Ice Removal
3.     Water
4.     Medical
5.     Vegetation
6.     Soils
7.     Vehicles
8.     Highways and Bridge Decks
9.     Utilities
10.    Safety
11.    Legal Implications
12.    General Reference Material
13.    Maintenance Procedures and Regulations
14.    Salt in the Atmosphere
15.    Additional References
                                95

-------
                                BIBLIOGRAPHY
General Environmental

1.    Adams, Franklin S, "Highway Deicing Salts are Potential Environmental
      Contaminants," Farm Economics,  Pennsylvania State University,  University
      Park, Pennsylvania, (1973).

2.    Adams, Franklin S., "Highway Salt:  Social and Environmental Concerns,"
      Highway Research Record No. 425, Highway Research Board, Washington,
      D.C.,(1973).                                             .

3.    American Automobile Association, "Deicing Salts: The Environmental Cost
      of Bare Pavement," Environmental News Digest, A.A.A., Washington,  D.  C.,
       (1972).

4.    Arthur D. Little, Inc., "Salt, Safety and Water Supply: Toward an
      Improved.Public-Policy for Using Road Salt," A policy study for the
      Special Commission on Salt Contamination of Water Supplies, Massachusetts
      General Court,  (1972).

5.    Behnke, Clifford C., "Road Salt is Harmful, Assembly Unit Told,"
      Wisconsin State Journal, Madison, Wisconsin,  (1973).

6.    Bried, Raymond, "The Great Salt Controversy," Yankee Magazine,   (1973).

7.    Chance R.L., "Corrosion, Deicing Salts, and the Environment," General
      Motors Research Laboratory, (1974) .

8.    Dadisman, Quincy, "Close Watch Urged on Use of Road Salt," Milwaukee
      Sentinel, Milwaukee, Wisconsin,  (1973).

9.    Public Works, "Deicing Salts and the Environment," Public Works,
      Vol.  102, No. 12, pp. 54-56,  (1971).

10.   Dickenson, William E., "Snow and Ice Control - A Critical Look at its
      Critics," Highway Research Record No. 227, Highway Research Board,
      Washington, D. C.,(1968).

11.    "Department of Public Works: Report Defending Road Salt Rejected by
      Environment Secretary," Boston Globe, Boston, Massachusetts,
       (1975).                                                  ;
 12.    "Economic  Impact of Pollution Control," Environmental Protection Agency-
       A Progress Report, December, 1970 - June 1972, pp. 47-57,  (1972).
                                        96

-------
13.   Massachusetts Department of Public Works,  "Environmental  Impact  Report:
      Snow and Ice Control Program,  (1974).

14.   "Facts You Should Know About Effects of Deicing Salt on the Environment",
      A review of National Cooperative Highway Research Program Report No.  91,
      Effects of Deicing Salts on Water Quality  and Biota,  Literature  Review
      and Recommended Research.,  American Public Works Association  Reporter,
      (1971).

15.   Field, Richard, et. al, "Environmental Impact of Highway  Deicing,"
      Environmental Protection Agency, Water Quality Research,  Edison, New
      Jersey, (1971).

16.   Field, Richard, et. al, "Water Pollution and Associated Effects  from
      Street Salting," Paper presented at the 45th Annual Conference of the
      Water Pollution Control Federation, Atlanta, Georgia,  (U.S. Environmental
      Protection Agency)   (1972).

17.   Gould, Whitney, "Road Salt  Takes a Licking as Traffic Hazard  Polluter,"
      The Capital Times,   Madison, Wisconsin, (1973).

18.   Gould, Whitney, "EPA Expert Backs Road Salt Warning,"  The Capital Times,
      Madison, Wisconsin,  (1973).

19.   Hanes, R.E., Zelanzy, L. W., and Blaser,,R. E.,  "Effects  of Deicing
      Salts on Water Quality and  Biota: Literature Review and Recommended
      Research," National Cooperative Highway Research Program  Report  No. 91,
      Highway Research Board, Washington, D. C.,(1970)-

20.   Hanes, R.E., et. al., "The  Effects of  Deicing Salts on Plant  Biota
      and Soils — Experimental Phase," National Cooperative Highway Research
      Program, Project 16-1-Final Report, Highway Research Board, Washington,
      D.C.,  (1972).

21.   Heydon, Howard S.,"The Environment —  Not  New But Current," Public Works,
      p. 69,  (1973).

22.   Hughmanick, Ronald N., "Environmental  Effects of Snow and Ice Control
      Programs," American Public  Works Association llth Annual  Show Conference,
      Chicago, Illinois,  April, 1971, Pennsylvania Department of Transportation,
      Bureau of Maintenance, Harrisburg, Pennsylvania.

23.   Hutchinson, F.E., "The Effect  of Deicing Salts Applied to Highways on
      the Contiguous Environment," Department of Plant and Soil Sciences,
      University of Maine, Orono,  Maine [n.d.]

24.   Hutchinson, F.E., "Environmental Pollution from Highway Deicing
      Compounds," Journal of Soil and Water  Conservation, 25:4:144-146 (1970).

25.   Kienitz, Richard C., "Effects  of Deicers for Roads Viewed," Journal,
      Madison, Wisconsin,  (1973) .             '.
                                       97

-------
26.   McConnelly, Hugh, et. al.,  "Deicing Salts and the Environment",
      Habitat School of Environment for the Massachusetts Audubon Society,
      Belmont, Massachusetts, (1972).                       '

27.   Minsk, L. David, "Use of Deicing Salt—Possible Environmental Impact,"
      Highway Research Record 425, Highway Research Board, Washington,  D.C.,
      (1972).                                               !

28.   Nisbet, Dr. I.C.T., "Has Salt Lost Favor?",  Conservation Leader,
      pp. 1-3, (1972).                                      !

29.   Nisbet, Dr. I.C.T., "Salty Words on Salty Roads," Massachusetts
      Audubon Newsletter, Vol. 14, No. 6, pp. 8-9, (1975).

30.   O'Keefe, John, "Environmentalists Criticize  Massachusetts Road Salting,"
      Boston Globe, Boston, Massachusetts, (1975).

31.   Olesen, Don, "What Is Highway Salt Doing to  Us," Milwaukee Journal,
      Milwaukee, Wisconsin, (1970).                         ;

32.   "On Wisconsin" Report on Highway Salting Ignores Environment,"
      The Milwaukee Journal, Milwaukee, Wisconsin, (1973).

33.   Patterson, Phillip, "Deicing Chemicals: Red  Flag for Ecology or
      Green Flag for Safety?", Rural and Urban Roads, pp. 31-33, (1973).

34.   "Pouring Salt on the Roads," Boston Globe, Boston, Massachusetts,
      (1975).

35.   Pryzby, S.Robert, "Deicing with Salt: Some Pros and Cons,"
      Public Works, pp. 80-81, (1971).

36.   "Public Reaction to Deicing Chemicals," Better Roads, pp. 27-29,
      (1968).

37.   Renn, Dr. Charles E., "Our Environment Battles Water Pollution,"
      Chestertown, Maryland: La Matte Chemical Products Company, (1969).

38.   A Review of Literature on the Environmental  Impact of Deicing Compounds
      and Snow Disposal, Water Resources Branch, Ministry of the Environment,
      Ontario, Canada, (1974).

39.   Rickenbach, Bruce A., "Snow and Ice Control," Yellow Springs, Ohio,
      (1974).  (mimeographed)

40.   "Salting Away Many Things," Chemistry,-46:20-21 (1973).

41.   "'Salting' the Environment," Mechanical Engineering, p.  42, (1972).

42.   Salt Institute, "The Case Against the Case Against the Use of Deicing
      Salts," Salt Institute, Alexandria, Virginia,  [n.d.]
                                      98

-------
43.   "Save Salt: Save the Environment," Better Roads,  pp. 28-29,  (1973).

44.   "Side Effects of Salting for Ice Control," American City, p.  33,  (1965).

45.   Scheldt, M.E., "Environmental Effects of Highways," Journal of the
      Sanitary Engineering Division, Proceedings of the American Society of
      Civil Engineers, '93:SA5:17-25, (1967).

46.   Schraufnagel, F.A., "Pollution Aspects Associated with Chemical Deicing,"
      Highway Research Record, No. 193, Highway Research Board, Washington,
      D.C., (1967).

47.   Schraufnagel, F.A./'Environmental Effects of Salt and Other Chemical
      Deicers," Department of Natural Resources, Madicon, Wisconsin,  (1973).

48.   Sharp, Robert W., "Road Salt as a Polluting Element," Special Environ-
      mental Release #3, Bureau of Sport Fisheries and Wildlife, Twin Cities,
      Minnesota, (1970).
                                                           i
49;   Smith, A.A.,  "Progess Report on NCHRP Project 16-1 Effects of Deicing
      Compounds on Vegetation and Water Supplies," National Cooperative
      Highway Research  Program,  paper presented at 54th Annual Meeting,
      American Association of State Highway officials, Minneapolis, Minnesota,
      (1968).

50.   Smith, H.A.,  "Environmental Effects of Snow Removal and Ice Control
      Programs," National Cooperative Highway Research Program, Paper
      presented at the llth Annual North American Snow Conference,  Chicago,
      Illinois,  (1971).

51.   Songer,  Lewis B., "The Effects of Snow Removal on the Community
      Economy," Paper presented at the 10th Annual North American Snow
      Conference, Boston, Massachusetts (mimeographed) (1970).

52.   Stratfull, R.F., Spellman, D.A.,  and Halterman, J.A., "Further
      Evaluation of Deicing Chemicals," State of California, Department of
      Transportation, Division of Highways, Transportation Laboratory,
      Research Report No. 635197-2, Federal Highway Administration Board-4-3,
      (1974).

53.   Terry, Robert D., Jr., Road Salt, Drinking Water and Safety;  Improving
      Public Policy and Practices, Cambridge, Massachusetts, Ballinger
      Publishing Co., (1974).

54.   U.S. Massachusetts Senate, "Legislative Research Council Report
      Relative to the Use and Effects of Highway Deicing Salts," Senate No.2,
      (1965) .

55.   Walker,  W.H., Wood, F.O.,"Road Salt Use and the Environment,"
      Highway Research Record 425, Highway Research Board,  Washington,  D. C.,
      (1973) .

56.   Whittle, Carolyn L., "The Case Against the Use of Highway Deicing
      Salts for Snow and Ice Control in Newton," Newtonville, Massachusetts,
      (1971).
                                      99

-------
57.   Wood, F.A., "The Role of Deicing Salts in the Total Environment
      of the Automobile," Paper presented at the National Association of
      Corrosion Engineers Symposium, (mimeographed)  (1970).


Costs of Snow and Ice Removal

58.   Anderson, Robert, Auster, Charles,"Costs and Benefits  of Road Salting,"
      Environmental Affairs, 3:11:128-144

59.   Baumann,  Duane D., Russell Clifford., "Urban Snow Hazard:  Economic
      and Social Implications," Water Research Report 37, Water Resources
      Center, University of Illinois, Urbana, Illinois,  (1971).

60.   Claffey, Paul J., "Passenger Car Fuel Consumption as Affected by Ice
      and Snow," Highway Research Record 383, Highway Research Board,
      Washington, D. C. (1972).

61.   Hopt, Roger L., Complete Salting - Sanding Economic Study,  Idaho
      Department of Highways, Maintenance Division, Boise, Idaho, (1971).

62.   "How to Assess the Economics of Urban Snow Problems,"  Rural and Urban
      Roads, Digest of D.G. Avery and D.D. Baumann, "Urban Snow Ha.zard:
      Economic and Social Implications," University of Illinois Water Resources
      Center, Urbana, Illinois, pp. 20-21,  (1972).

63.   Hubbard, Wylie, "Sensible Salting Saves Dollars and Environment," Rural
      and Urban Roads, pp. 62-63, (1972).                    ,

64.   Ireland, Donald, "Salt Particle Size Affects Fuel Use," Rural and
      Urban Roads, pp. 50-52, (1974).

65.   Madden, Jim L., "The Use of Salt for Ice and Snow Control in Rochester:
      A Cost-Benefit Study," Systems Analysis Program; Working Paper Series
      No. 7124, University of Rochester, New York,  (1971).

66.   "Maintenance Cost Study: Final Report," Ohio Department of Highways,
      Bureau of Maintenance, Columbus, Ohio,  (1971).

67.   O'Brien, Robert G.,  "Road Salt - One Town's Cost Analysis,." Better Roads,
      pp. 22-23,  (1973).                                     ;

68.   "Proposal for  'Economic Impact of Highway Snow and Ice Control',"
      Research and Development Section, Utah Department of Highwciys,  (1974).

69.   Carnegie-Mellon, Study of Road Maintenace in The Pittsburgh Area,
      Physical Technical Systems, Final Report, School of Urban and Public
      Affairs, Carnegie-Mellon University, Pittsburgh, Pennsylvania  (1972).
                                      100

-------
Water

70.   Ackermann, William C., Harmeson, Robert H.,  and Sinclair,  Robert A.,
      "Some Long Term Trends in Water Quality of Rivers and Lakes,"  American
      Geophysical Union, E©S 51:6:516-522 (1970).

71.   Black, Herbert, "Salt Buildup in Drinking Water a Danger to Some Bay
      Staters," Boston Globe, Boston, Massachusetts,  (1970).

72.   Bowers, George N. Jr., "The Effect of Highways  on Public Drinking
      Water Supplies in Connecticut," Text of statements read at Earth Day
      Rally, W. Hartford Green, Connecticut (1970).

73.   Bubeck, Robert C., et. al., "Runoff of Deicing  Salt;  Effect on
      Irondequoit Bay, Rochester, New York," Science, 172:1128-1132  (1971).

74.   Caldwell, Jean, "Road Salt Blamed for Souring Water," Boston Globe,
      Boston, Massachusetts, (1970).

75.   Colston,  Newtown, F., Jr., "Characterization and Treatment of Urban
      Land Runoff," Environmental Protection Technology Series,  EPA-670/2-74-096,
      U.S. Environmental Protection Agency, Cincinnati, Ohio, (1974).

76.   Crawford, Diana, "Alewife Book Polluted," Boston Globe, Boston,
      Massachusetts,  (1970).

77.   Creatura, J.A., "Irrigation-Water Quality of the New York-New  England
      Region,"  New England Water Works Association Journal, 74:151-160 (I960).

78.   Deicing Salt as a Source of Water Pollution, Ontario Water Resources
      Commission, Water Quality Surveys Branch, Ontario, Canada, (1971).

79.   Deutsch, Morris, "Ground-Water Contamination and Legal Controls in
      Michigan," Geological Survey Water - Supply Paper 1691, U.S. Government
      Printing Office, Washington, D. C. (1973).

80.   Diment, W.H.,  et. al., "Some Effects of Deicing Salts on the Waters of
      the Irondequoit Bay Drainage Basin, Monroe County, New York,"  Department
      of Geological  Sciences, University of Rochester, New York (1972).

81.   Diment, W.H.,  Bubeck,, R.C., Deck, B. L., "Some Effects of Deicing
      Salts on Irondequoit Bay and Its Drainage Basin," Highway Research
      Record 425, Highway Research Board, Washington, D. C.  (1973).

82.   Feick, G., Horne, R.A., Yeaple, D., "Release of Mercury from Contamin-
      ated Fresh Water Sediments by the Runoff of Road Deicing Salts,"
      Science,  Vol.  175, pp. 1142-1143, (1972).

83.   Fenton, Richard, "Comments on the Federal E.P.A. Report 'Water
      Pollution and  Associated Effects from Street Salting'," Paper
      presented at a meeting of the Highway Research Board, Washington,
      D. C.,  (1974).
                                       101

-------
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
 98.
Fieldman, H. W., "Ferrocyanide and Cyanide in Salt Pile Runoff,"
(Abstract-mimeographed) (1974) .

Field, Richard./'Management and Control of Combined Sewer Overflows','
Edison Water Quality Research Division, U.S. Environmental Protection
Agency, Edison, New Jersey (1972).                     :

Godsoe, William D., "Do Road .Salts Poison Water Supplies,?" Boston Globe,
Boston, Massachusetts,  [n.d.]

Gould, Whitney, "Road Salt Endangers Some Wells in State," The Capital
Times, Madison, Wisconsin, (1973).

Groebner, James F., "Report of Analysis of Salt Content of Samples
from Diamond Lake, Hennepin County," Report of Fish Kill, Minnesota
Department of Natural Resources, St. Paul, Minnesota,  (1967).

Hawkins, R.H., Judd, J. H., "Water Pollution as Affected by Street
Salting," Water Resources Bulletin, 8:6:1246-1252  (1972).

Ruling E.E., Hollocher, T. C., "Groundwater Contamination by Road
Salt: Steady State Concentrations in East Central Massachusetts,"
Science, 176:288-290  (1972).                           '•

Hutchinson, F.E.,  "The Effect of Highway Salt on Water Quality in
Selected Main Rivers," Department of Plant and Soil Sciences, University
of Main, Orono, Maine,  [n.d.]                          :

                „  "The Nature of Water Pollution and Its Relevance to
Maine," Bulletin 561, Cooperative Extension Service, University of
Maine, Orono, Maine,  [n..d.]

  	,  "Concentration of 9 Inorganic Ions in Maine Rivers,"
Research in the Life Sciences, pp. 8-11,  (Winter, 1968),.

	,  "Effect of Highway Salting in the Concentration of
Sodium and Chloride in Rivers," Research  in the Life Sciences, Vol. 15,
NO.  4, pp. 12-14,  (1968).

	,  "Effect of Highway Salting on the Concentration of
Sodium and Chloride in Private Water Supplies," Research in the Life
Sciences, pp.  15-19,  (1969).

	,  "The Influence of Salts Applied to Highways on the
Levels of Sodium and Chloride Ions Present in Water and Soil Samples,"
Project Completion Report,  Project #R  1090-8, University of Maine, Orono,
Maine,  (1969).

Judd, John H., "Effect of Salt Runoff  from Street Deicing on a Small
Lake," Ph.D.  Thesis, University of Winsoncon,  (1969).

	, "Lake Stratification Caused by Runoff from Street
Deicing," Water Research, 4:8:521-532  (Great Britain)  (1970).

                                102

-------
99.   Karubian, John F.,  "Polluted Groundwater:  Estimating the Effects
      of Man's Activities," Environmental Monitoring Series,  EPA 680/4-74-002,
      U.S. Environmental  Protection Agency,  Las  Vegas,  Nevada (1974).

100.  Kunkle, Samuel H.,  "Effects of Road Salt on a Vermont Stream,"
      Journal of the American Water Works Association,  Vol. 64, No.  5,  pp.  290-5,
      (1972).

101.  "Sodium Chloride Content of Drinking Waters," Massachusetts Department
      of Public Health, Division of Environmental Health, (mimeographed)
      (1970) .

102.  McConnell, H. Hugh and Lewis, Jennifer,   "...Add Salt to Taste,"
      Environment, pp. 38-44, (1972).

103.  Meredith, D.D., Rumer, R.R., Jr., Chien, C.C., Apmann,  R. P.,  "Chloride
      in Lake Erie Basin," Water Resources and Environmental Engineering
      Research Report No. 74-1, Department of Civil Engineering, State Uni-
      versity of New York at Buffalo,  (1974).

104.  Motts, Ward S., Saines, Marvin, "Increase of Mineralization of Public
      Ground-Water Supplies in Massachusetts," Public #7, Water Resources
      Research Center, University of Massachusetts, Amherst,  Massachusetts,
      [n.d.]

105.  Myles, Bruce, "Road Salt Use Major Threat to Water Supplies,"
      Christian Science Monitor, Boston, Massachusetts,  (1974).

106.  Newton, D.W., Ellis, Roscoe, Jr., "Loss of Mercury  (II) from Solution,"
      Journal of Environmental Quality, 3:1:20-23  (1974).

107.  Oliver, Barry G., Milne, John B., LaBarre, Norman, "Chloride and Lead
      in Urban Snow," Journal of the Water Pollution Control Federation,
      46:4:766-771,  (1974).

108.  Pacini, Paul R., "The Impact of Street Salting on  the Clark Fork River,"
      Missoula, University of Montana,  (mimeographed)  (1972).

109.  Paullin, Dave,  "Sodium Concentrations in the Snow  of Missoula, Montana,"
      Missoula: University of Montana,  (mimeographed)  (1972).

110.  Pollock, S.J.,  "Salt Contamination of the Water Supply at Auburn,
      Massachusetts,"  U.S. Geological  Survey in Cooperation with the Massachusetts
      Department of Public Works,  (1971).

111.  Pollock, S.J.,  Toler, L. G.,  "Effects of Highway Deicing Salts on
      Groundwater  and Water Supplies in Massachusetts,"  Highway Research
      Record 425,  Highway  Research Board, Washington, D. C.  (1973).

112.  Rahn,  P.H.,  Perry, H.,"Movement  of Dissolved Salts in  Groundwater
      Systems," Symposium: Pollutants  in the Roadside Environment, University
      of  Connecticut and Connecticut State  Highway Department, pp. 36-45,
       (1968).
                                       103

-------
113.  Raymond, Lyle S., Jr., "Synopsis:  Salt Pollution of Water Supplies,"
      Cornell University Water Resources and Marine Sciences Center,  Ithaca,
      New York, (1974).

114.  "Report Relative to Salt Contamination of Existing Well Supplies,"
      Whitman and Howard, Inc., Boston,  Massachusetts, (1971).;

115.  "Salting Highways Could Contaminate Ground Water," Reclamation News,
      (1965).

116.  Sawyer, Clair N., "Fertilization of Lakes by Agricultural and Urban
      Drainage," New England Water Works Association, 61:2:109-127 (1947).

117.  Schraufnagel, F.H., "Chlorides," Committee on Water Pollution,  Madison,
      Wisconsin, (1965).

118.  Soderlund, G., Lehtinen, H., Friberg, S., "Physiochemical and Micro-
      biological Properties of Urban Stormwater Runoff," Paper! presented at
      the 5th International Water Pollution Research Conference, San Francisco,
      California,  (1970) .                                     '•

119.  Stevens, Leo C., Jr., "Effects of Deicing Chemicals Upon Surface and
      Groundwater:  Initial Program Development," Research Paper 72-1, Department
      of Public Works, Boston, Massachusetts,  (1972).

120.  	, "Effects of Deicing Chemicals Upon Groundwater  and
      Surface Structures - Project Description," New England Water Works
      Association,  88:1:1-7,  (1973).

121.  Street Salting Urban Water Quality Workshop, State University of hNew
      York Water Resources Center, Syracuse, New York,  (1971).

122.  Sylvester, Robert O., Dewalle, Foppe B., "Character and Significance  of
      Highway Runoff Waters: A Preliminary Appraisal," Research Report Y-1441,
      Washington State Highway Commission and U.S. Department ;of Transportation,
      Federal Highway Administration, (1972).

123.  Toler, Larry, "Effect of Deicing Chemicals on Ground and Surface Water,"
      Research Project R-18-1, Progress Report, U.S. Geological Survey, Boston,
      Massachusetts,  (1972).

124.  Toler, L.G., Pollock, S. J., "Retention of Chloride in the Unsaturated
      Zone," Journal Research U.S. Geological Survey, 2:1:119-123 (1974).

125.  Walker, William H., "Limiting Road Salt Pollution of Water Supplies,"
      Illinois State Water Survey, Urbana, Illinois  [n.d.]    :

126.  	, "Road Salt Pollution of a Shallow Aquifer in the
      Peoria Area  of West-Central Illinois," Illinois State Water Survey,
      Urbana, Illinois,  (1969).

127.
,  "Salt Piling — A Source of Water  Supply Pollution,"
      Pollution Engineering, pp. 30-33,  (1970).

                                       104

-------
128.  Walker, W. H., "Water Pollution in Perspective,"  Water and Sewage Works,
      118:7:205 (1971).

129.  Weibel, S.R.,  et.  al., "Characterization,  Treatment and Disposal of
      Urban Stormwater," Third International Conference on Water Pollution
      Research, Section 1, Paper No.  15, Water Pollution Control Federation,
      Washington, D. C., (1966).

130.  Weigle, James M.,  "Groundwater Contamination by_Highway Salting,"
      Highway Research Record 193, Highway Research Board, Washington, D. C.,
      (1967).

131.  Wolf, Harold W.,  Esmond, Steven E., "Reuse of Wastewater for Drinking
      Purposes - Research into an Acceptable Level of Sodium," Water and Sewage
      Works, pp. 49-54,  (1974).
Medical

132.  "Conquering the Quiet Killer," Time, pp. 60-64, (1975).

133.  Cooper G., Heap, Beth, "Sodium Ion in Drinking Water: II. Importance,
      Problems and Potential Applications of Sodium-Ion Restricted Therapy,"
      Journal of the American Dietetic Association, 50:1:37-41 (1967).

134.  Dahl, Lewis K., "Salt and Hypertension," American Journal of Clinical
      Nutrition, 25:231-244 (1972).

135.  Garrison, G.E., Ader, O.L., "Sodium in Drinking Water: Pitfall in
      Maintenance of Low Sodium Diet," Archives of Environmental Health,
      13:11:551-553 (1966).

136.  Joosens, J.V., "Salt and Hypertension, Water Hardness and Cardiovascular
      Death Rate," Triangle, 12:1:9-15  (1973).

137.  Kirkendall, Walter W., "Salt and Hypertension," Paper presented to the
      Nutrition Select Committee, U.S. Senate  (mimeographed),  (1974).

138.  Page, Lot, "Epidemiologic Evidence on the Etiology of Human Hypertension
      and  Its Possible Prevention," Newton-Wellesley Hospital and Tufts
      University School of Medicine, Boston, Massachusetts,  (mimeographed)
       [n.d.]

139.  Page, L.B., Damon A., Moellering, R.C.,  Jr., "Antecedentts of Cardio-
      vascular Disease in Six Solomon Islands  Societies," Circulation,
      49:1132-1146  (1974).

140.  "Pointing the Finger  at Salt," Newtown Wellesley Quarterly, p. 11,  (1973)

141.  Russell, Edward, M.D., "Sodium Imbalance in Drinking Water,"
      Journal  of the American Water Works Association,  62:2:102-105  (1970).
                                       105

-------
142.  Simkins, Michael H., "Feasibility Report on Regulating Water Supplies
      Containing Sodium Chloride," Central Michigan University, (mimeographed),
      (1975).                                                ;   '

143.  "What to do When Your Numbers are Up — High Blood Pressure," Consumer
      Reports, pp. 735-739, (1974).

144.  White, J. M., et. al., "Sodium Ion in Drinking Water I:  Properties,
      Analysis and Occurrence," Journal of the American Dietetic Association,
      50:1:32-36, (1967).                  ~~~~          ~  !	

145.  Wolf, Harold W., Moore,  Billy J., "is A Sodium Standard Necessary,?"
      Paper presented at the Water Quality Technology Conference,  Cincinnati,
      Ohio, (1973).                                           :
Vegetation

146.  Baker, J.H., "Relationship Between Salt Concentrations in Leaves and
      Sap and the Decline of Sugar Maples Along Roadsides," Experiment Station
      Bulletin 553, University of Massachusetts, Amherst (1965).

147.  Bernstein, Leon, "Salt Tolerance of Field Crops," Agricultural
      Information Bulletin 217, U.S. Department of Agriculture, Washington,
      D.C., (1959).

148.  Bernstein, Leon, "Salt Tolerance of Vegetable Crops in the West,"
      Agricultural Information Bulletin 205, U.S. Department of Agriculture,
      Washington, D. C. (1959).
149.
150.
151.
               , "Salt Tolerance of Plants," Agricultural Information
Bulletin 283, U.S. Department of Agriculture, Washington, D. C., (1964).

	, "Salt Tolerance of Fruit Crops," Agricultural Information
Bulletin 292, U.S. Department of Agriculture, Washington, D. C. (1965).

	, "Salt Tolerance of Grasses and Forage Legumes,"
      Agricultural Information Bulletin 194, U.S. Department of Agriculture,
      Washington, D. C. (1965).
152.  Bernstein, L., Shear, C.B., Lattaye and Epstein, "Calcium and Salt
      Tolerance of Plants," Science, 167:1387-8 (1970).

153.  Bernstein, Leon, Francois, L.E., Clark, R.A., "Interactive Effects of
      Salinity and Fertility on Yields of Grain and Vegetables," Agronomy
      Journal, 66:412-421, (1974).                           '.

154.  Butler, J.D., "Salt Tolerant Grasses for Roadsides," Highway Research
      Report 411, Highway Research Board, Washington, D. C. (1972).

155.  Butler, J.D., Hughes, T.D., Sanks, G.D., Craig, P. R.,  ''Salt Causes
      Problems Along Illinois Highways," Illinois Research 13::4, University
      of Illinois Agricultural Experiment Station (1971).

                                      106

-------
156.   Button,  E.F.,  "Influence of Rock Salt Used for Highway Ice  Control
      on Mature Sugar Maples at one Location in Central  Connecticut,"
      Report #3, Connecticut State Highway Department,  (1964).

157.   Button,  E.F.,  Peaslee, D.E., "The Effect of Rock Salt upon  Roadside
      Sugar Maples in Connecticut," Highway Research Report 161,  Highway
      Research Board, Washington, D. C., (1967).

158.   Carpenter, Edwin D./ "Salt/and Landscape Plantings,"  Cooperative
      Extension Service, College of Agriculture and Natural Resources,
      University of Connecticut, Storrs, Connecticut (1971).

159.   Gavitt,  Bud, ed., "Deicing Salts Severely Damage Key  Element in
      Life of Maple Trees," College of Agriculture and Natural  Sciences
      News Office, University of Connecticut, Storrs, (1974).

160.   Hanes, R.E., Zelazny, L.W., Blaser, R.E., "Salt Tolerance.of Trees and
      Shrubs to Deicing Salts," Highway Research Record  335, Highway Research
      Board, Washington, D. C., (1970).

161.   Harter,  Robert D., "The Effect of Road Deicing Salt on Forest Soil
      and Vegetation, Project Outline," College of Life  Sciences  and
      Agriculture, New Hampshire Agricultural Experiment Station, Institute
      of Natural and Environmental Resources, University of New Hampshire,
      [n.d.]

162.   Hall, R., Hofstra, .G., Lumis, E.P., "Effect of-Deicing Salt on Eastern
      White Pine:  Foliar Injury, Growth Suppression, and Seasonal Changes
      in Foliar Concentrations of Sodium and Chloride,"  Canadian  Journal of
      Botany,  2:3:244-249  (1972).

163.   Hall, R., Hofstra, G., Lumis, G.P., "Leaf Necrosis of Roadside Sugar
      Maple in Ontario in Relation to Elemental Composition of  Soil and Leaves,"
      Phytopathology, 63:11:1426-1427  (1973).

164.   Hofstra, G., Hall, R., "Injury on Roadside Trees;  Leaf Injury on Pine
      and White Cedar in Relation to Foliar Levels of Sodium and Chloride,"
      Canadian Journal of Botany, 49:4:613-622  (1971).

165.   Hofstra, G., Lumis, G.P., "Levels of Deicing Salt Producing Injury
      on Apple Trees," Canadian Journal of Plant Science, 55:113-115  (1975).

166.   Holmes, Francis W.,  "Salt Injury to Trees," Phytopathology, 51:10:712-718,
      (1961).

167.   Holmes, Francis W.,  "Effects on Street Trees of the Use of  Salt  as  a
      Snow Control Chemical," Paper presented at 39th Annual Meeting,  New
      Jersey Federation of Shade Trees Commissions,  (1974).

168.   	,  "Salt Damage to Tree's and Shrubs," Shade Tree
      Laboratories, University of Massachusetts, Amherst (1966).
                                      107

-------
169.  	/ A Partial Bibliography on Salt Injury to the Environment,
      Expecially to Trees, Shade Tree Laboratories, University of Massachusetts,
      Amherst (1973).

170.  Holmes, F.W., Baker, J.H., "Salt Injury to Trees II Sodium and Chloride
      in Roadside Sugar Maples in Massachusetts," Phytopathology, 56:6:633-636,
      (1966).

171.  Lacasse, Norman L., Rich, Avery E., "Maple Decline in New Hampshire,
      Phytopathology, 54:1071-1075, (1964).

172.  "Low Cost Ecologically Safe Antidote to Grass Brownout from Salt,"
      Better Roads, p. 24, (1973).

173.  Piatt, J.R., Krause, Paul D., "Road and Site Characteristics that Influence
      Road Salt Distribution and Damage to Roadside Aspen Trees," Water,  Air
      and Soil Pollution, 3:301-304 (1974).                       '

174.  Rich, Avery, E., "Effect of Deicing Chemicals on Woody Plants,"
      Symposium; Pollutants in the Roadside Environment,  edited by Edwin D.
      Carpenter, University of Connecticut, (1968).

175.  Rich, Avery, E., "Some Effects of Deicing Chemicals on Roadside Trees,"
      Highway Research Record 425, Highway Research Board, Washington, D.»C.,
      (1973).                                                 ;

176.  Roberts, H.C., Eliot, C., "Effect of Deicing Chemicals on Grassy Plants,"
      Symposium; Pollutants in the Roadside Environment, edited by Edwin D.
      Carpenter, University of Connecticut, (1968).

177.  Roberts, Eliot C., Zybura, Edwin L., "Effect of Sodium Chloride on
      Grasses for Roadside Use," Highway Research Record 193, Highway Research
      Board, Washington, D. C.  (1967).

178.  Rowell, D.L., Erel, Kamil, "The Effect of the Intensities of Potassium
      and Sodium in Soil on the Growth of Sugar Beet," Journal of Agricultural
      Science, 63:223-231, (1971).

179.  Shortle, Walter C., Rich, Avery, E., "Relative Sodium Chloride Tolerance
      of Common Roadside Trees in Southeastern New Hampshire,", Plant Disease
      Reporter, 54:4:361-363, (1970).

180.  Shortle, Walter C., Kotheimer, John B., Rich, Avery E., "Effect of
      Salt Injury on Shoot Growth of Sugar Maple - Acer Saccharum," Plant
      Disease Reporter, 56:11:1004,1007  (1972).

181.  Smith, William H., "Salt Contamination of White Pine Planted Adjacent
      to an Interstate Highway," Plant Disease'Reporter, 54:12:1021-1025, (1970).

182.  "Study Indicates No Proof of Salt Damage to Roadsides," Journal, Madison,
      Wisconsin, (1973).
                                       108

-------
183.  Sullivan, "Effects of Winter Storm Runoff on Vegetation and as  a
      Factor in Stream Pollution," Paper presented at the 7th Annual  Snow
      Conference, Milwaukee, Wisconsin, (1967).

184.  Thomas, Lindey  Kay Jr., "Notes on Winter Road Salting (Sodium  Chloride)
      and Vegetation," Scientific Report No. 3, National Park Service, Washington,
      D.C.,  (1965) .

185.  Thomas,. Lindey K., Jr., "A Quantitative Microchemical Method for
      Determining Sodium Chloride Injury to Plants," Scientific Report #4,
      National Park Service, Washington, D. C., (1965).

186.  	__, "Road Salt (Sodium Chloride) Injury to  Kentucky
      Bluegrass," Highway Research Report 161, Highway Research Board,
      Washington, D. C.,  (1967).

187.  	, "winter Rock Salt Injury to Turf (Poa pratensis L,"
      Scientific Report #5, National Park Service, Washington, D. C.,  (1965).

188.  Verghese, K.G., et. al., "Sodium Chloride Uptake and Distribution in
      Grasses  as Influenced by Fertility Interaction and Complementary Anion
      Competition," Unpublished report, Virginia Polytechnic Institute,
      Blackburg, Virginia  [n.d.]

189.  Verghese, K.G., Hanes,  R.E., Zelazny, L. W., Blaser, R.E., "Sodium^
      Chloride Uptake in  Grasses  as  Influenced by Fertility Interaction,"
      Highway  Research Record 335, Highway  Research Board, Washington, D.C.,
       (1970).

190.  Wester,  H.V., E.E.  Cohen, "Salt  Damage to Vegetation in the Washington,
      D.C., Area  during the 1966-1967  Winter," Plant Disease Reporter,
      52:5:350-354  (1968).

191.  Westing, Arthur  H.,  "Plants and  Salt  in  the Roadside Environment,"
      Phytopathology,  59:9:1174-1181 (1969).

192.   Zelazny, Lucian,  "Salt Tolerance of Roadside Vegetation,"  Symposium:
      Pollutants  in the Roadside  Environment," edited  by Edwin D. Carpenter,
      University of Connecticut,  (1968).


Soils

193.   Brandt,  G.H., "Potential  Impact  of Sodium Chloride and Calcium Chloride
       Deicing Mixtures on Roadside Soils and Plants,"  with discussion by
       Hutchinson, Westerman,  Rubins, and Rich, Highway Research  Record 425,
       Highway Research Board, Washington,  D.-C.  (1973).

 194.   Hutchinson, F.E., B.E. Olson,  "The Relationship of Road Salt Applications
       to Sodium and Chloride Ion Levels in the Soil Bordering Major  Highways,"
       Highway Research Record 193, Highway Research Board, Washington, D. C.
       (1967).
                                       109

-------
 195.   Hutchinson,  Frederick E.r  "Dispersal of  Sodium  Ions  in Soils,"
       Materials  and Research Technical  Paper 71-10C,  University of Maine,
       in cooperation with the Main State  Highway Commission,  (1971).

 196.   Hutchinson,  F.  E.,  "Dispersal of  Soil-Bound Sodium from Highway
       Salting,"  Public Works, pp.  69-70,  (1972).

 197.	,  "Supplemental Report II for Cooperative Project
       Entitled 'Dispersal of Sodium Ions  in Soils',"  University of Maine,
       Orono, Maine,  (mimeographed),  (1974).

 198.   Prior Dr., George A.,  "Salt  Migration in Soil," Symposium: Pollutants
       in the Roadside Environment,  edited by Edwin D. Carpenter, University
       of Connecticut,  (1968).

 199.   Prior, George A., Berthouex,  Paul M., "A Study  of Salt Pollution of
       Soil by  Highway Salting," Highway Research Record 193, pp. 8-21,
       Highway  Research Board, Washington,  D. C. (1967).

 200.   Zelazny, L.M.,  Blaser, R.E.,  "Effects of Deicing Salts on Roadside
       Soils and Vegetation," Highway Research  Record  335, Highway Research
       Board, Washington, D.  C.  (1970).                        :

 201.   Zelazny, L.W.,  Hanes,  R.E., Blaser,  R. E., "Effects of Deicing Salts
       on  Roadside Soils and Vegetation: I. Movement Distribution in a Vergennes
       Soil," Virginia Polytechnic  Institute Research Division, Blacksburg,
       Virginia,  [n.d^](unpublished paper).                    :


Vehicles

202.   Bishop, R.R., "Corrosion of Motor Vehicles by Deicing Salt - Results
       of  a Survey," Road Research Laboratory Report #LR232, Road Research
       Laboratory, Crowthorne, England (1968).

203.  Bishop, R.R., "The Development of a Corrosion Inhibitor for Addition
       to Road Deicing Salt," Transport and Road Research Laboratory,  Crowthorne,
      England, (1972).

204.  Burke,  Mark A., "What Ever Happened to Automobile Body Corrosion,"
      Vehicle Safety Engineering and Standards  Department,  Motor Vehicle
      Manufacturers Association.

205.  Fromm,  H.J., "Corrosion of Auto-Body Steel and the Effects of Inhibited
      Deicing Salts," Highway Research Record 227,  Highway  Research Board,
      Washington, D. C.  (1968).

206.  Motor Vehicle Corrosion and Influence of  Deicing Chemicals,  Paris:
      Organization for Economic Cooperation and Development, Road Research
      Group C2 (1969),

207.  Palmer, J.D., "Corrosive Effects of Deicing  Salts on  Automobiles,"
      Materials Protection and Performance, pp. 38-43, (1971).:
                                      110

-------
208.
209.
210.
Thurmann, Moe T., Ruud, O.E., "Vehicle Corrosion  Due to the Use of
Chemicals in Winter Maintenance and the Effect of Corrosion Inhibitors,"
Oslo: Norwegian Road Research Laboratory, 44:15-29, (1973).

"Vehicle Corrosion Caused by Deicing Salts," Special Report 34, American
Public Works Association, (1970).

Waindle, R.F., "Automotive Body Rusting-Causes/Cures," Presented at the
meeting of the Institute of Traffic and Engineering, U.C.L.A., Extension,
Los Angeles (1967).
Highways and Bridge Decks

211.  Herman, H.A., "The Effects of Sodium Chloride on the Corrosion of
      Concrete Reinforcing Steel and on the pH of Calcium Hydroxide Solution,"
      FHWA-RD-74-1, Federal Highway Administration, Washington, D. C., (1974).

212.  Berman, Horace, Chaiken, Bernard, "Techniques for Retarding the
      Penetration of Deicers into Cement Paste and Mortar," Public Roads,
      38:1:9-19,

213.  Blackburn, Robert R., et. al., "Economic Evaluation of the Effects of
      Ice and Frost on Bridge Decks," Midwest Research Institute, Project
      #3564-E, p. 261, Kansas City, Missouri, (1971).

214.  Boulwane, R.L., Stewart, C.F., "Bridge Deck Restoration Aid Procedures:
      Field Electrical Measurements for Bridge Deck Membrane Permeability
      and Reinforced Steel Corrosion," California Division of Highways, (1973).

215.  Carroll, Robert J., "Evaluation of the Effectiveness of Membrane Water
      Proofing for Concrete Bridge Decks," Ohio Department of Transportation,
      Bureau of Research and Development,  (1973).

216.  Clear, K.C., "Evaluation of Portland Cement Concrete for Permanent
      Bridge Deck Repair," FHWA-RD-74-5, Federal Highway Administration, (1974).

217.  Clear, K.C., Hay, R.E., "Time to Corrosion of Reinforcing Steel in
      Concrete Slabs Volume I: Effect of Mix Design and Construction Para-
      meters," Interim Report FHWA-RD-73-32, Federal Highway Administration,
      Washington, D. C. (1973).

218.  Clifton J.F., Beighly, H.F., Mathey, R.G., "Non-Metallic Coatings for
      Concrete Reinforcing Bars," FHWA-RD-74-18, Federal Highway Administration,
       (1974).

219.  "Corroding Elevated Highway Closed Poor Maintenance Cited," Engineering
      News Record, p. 21,  (1974).

220.  Grieb, W.E., "Silicones as Admixtures for Concrete," Highway Research
      Record 18, Highway Research Board,  (1963).
                                      Ill

-------
221.
222.
223.
224.
Hardesty and Hanover, "Report on the Inspection and Analysis of the
West Side Highway  (Henry Hudson Parkway) 72nd Street-79th Street,"
Capital Project No. HW-152, for the Transportation Authority, New York,
(1974).                   .

Hardesty and Hanover, "Report on the Inspection and Analysis of the
West Side Highway  (Henry Hudson Parkway) 42nd Street-59th Street,"
Capital Project No. HW-19 for Transportation Authority, New York City,
(1974).

	, "Report on the Inspection and Analysis of the
West Side Highway  (Henry Hudson Parkway) 59th Street-72nd Street,"
Capital Project No. HW-152 for the Transportation Authority, New York
City  (1975).

	, "Report on the Inspection and Analysis of the
225.

226.



227.



228.



229.



230.


231.



232.


233.


234.
West Side Highway  (Henry Hudson Parkway) Battery to 42nd Street,"
Capital Project No. HW-19 for Transportation Authority,\ New York City
(1975).

Hay, R.E., Personal Correspondence with Robert Anderson on August 1974.

Hilsdorf, H.K., Loff, J.L., "Revibration of Retarded Concrete for
Continuous Bridge Decks," National Cooperative Highway ^Research Program
Report 106, Highway Research Baord, Washington, D. C. [n.d., ]

Houston, J.T., et. al., "Corrosion of Reinforcing Steel Embedded in
Structural Concrete," Research Report 112-1F, University of Texas at
Austin,  (1972).

Kaiser Cement  and Gypsum Corporation, "Effect of Various Sxxbstances
on Concrete and Recommended Protective Treatments," Concrete Topics,
Technical Service Department Bulletin No. 16  [n.d.]

Kallas, B.F.,  "Performance of Asphalt Pavements Subjected to Deicing
Salts," Highway Research Record 24, Highway Research Board,, Washington,
D. C., (1963).

Klietherraes, J., "Repair of Spalling Bridge Decks," Highway Research
Record 400, Highway Research Board, Washington, D. C. (1972).

"Concrete Bridge Deck Desirability," National Cooperative Highway
Research Project, Synthesis of Highway Practice #4, Highway Research
Board, Washington, D. C.  (1970).

"Winter Damage to Road Pavements," Paris" Organization for Economic
Cooperation and Development, Road Research Group C2,  (1972).

"Waterproofing of Concrete Bridge Decks," Paris: Organization for
Economic Cooperation and Development, Road Research Group C2, (1972).

Pike, R.G., et. al., "Nonmetallic Coatings for Concrete Reinforcing
Bars," Public  Roads, 37:5:185-197  (1973).
                                      112

-------
235.   Snyder,  M.  Jack.,  "Protective Coatings to Prevent Deterioration of
      Concrete by Deicing Chemicals," National Cooperative Highway Research
      Program Report #16, Highway Research Board,  Washington,  D.  C.,  (1965).

236.   Spellman, D.L., Stratfull, R.F., "Chlorides  and Bridge Deck Deterioration,"
      Highway Research Record 328, Highway Research Board, Washington, D.  C.  (1970.

237.   Stark, David, "Studies of the Relationships  among Crack Patterns, Cover
      Over Reinforcing Steel and Development of Surface Spalls in Bridge Decks,"
      Special Report 116, Highway Research Board,  Washington,  D.  C. (1971).

238.   Stewart, C.F., "Deterioration in Salted Bridge Decks," Special  Report
      116, Highway Research Board, Washington, D.  C., (1971).

239.   Stewart, C.F., "Bridge Deck Restoration — Methods and Procedures:
      Bridge Deck Seals," California Division of Highways (1972).

240.	, "Bridge Deck Restoration — Methods and Procedures:
      Repairs," California Division of Highways, (1972).

241.   Stratfull, R.F., "Experimental Cathodic Protection of a Bridge  Deck,"
      Transportation Laboratory, Department of Transportation, California
      (1974).

242.   Stratfull, R. F., Van, M.V., "Corrosion Autopsy of a Structurally Unsound
      Bridge Deck," California Division of Highways,  (1973).

243.   Tripler,'A.B., et. al., "Methods for Reducing Corrosion of Reinforcing
      Steel," National Cooperative Highway Research Program Report 23,
      Highway Research Board, Washington, D. C., (1966).

244.   Yamanskir R.S., "Coatings to Prevent Concrete from Damage by Deicer
      Chemicals: A Literature Review," Journal of Paint Technology,
      39:509:394-397  (1967).
Utilities

245.  Berthouex, Paul M., Prior,  George A., "Underground Corrosion and Salt
      Infiltration," Journal of the American Water Works, 60:3:345-355, (1968).

246.  Various memos on salt usage and salt-related damage, Con Edison, New
      York  (1974).
 Safety

 247.  Anti-Skid Program Management and Related Papers, Highway Research Record
      376,  22  reports, Highway Research Board, Washington, D. C.  (1971).

 248.  Anderson, Robert C.,  "The Economics of Highway Safety," Traffic Quarterly,
      pp. 99-111,  (1975).
                                        113

-------
249.  Arvai, Ernest S., "The Effect of Salt on the Number of Winter Accidents,"
      HIT Laboratory Reports, Highway Safety Research Institute, University
      of Michigan, (1971) .

250.  Committee on Winter Driving Hazards, "1973 winter Test Program," National
      Safety Council, Stevens Point, Wisconsin (1973).

251.  Dadisman, Quincy, "Salt on Roads Blamed in Some Crashes," Milwaukee
      Sentinel, Milwaukee, Wisconsin, (1973).

252.  Ichihara, K.> Mizoguchi, M., "Skid Resistance of Snow or Ice-Covered
      Roads," Special Report 115, Highway Research Board, Washington,  D.  C.
      (1970).                                                 ]

253.  Lockwood, R.K., "Effect of Winter Weather on Traffic Accidents," Chapter
      8 in Snow Removal and Ice Control in Urban Aaeas, Research Report #114,
      American Public Works Association, (1965).

254.  Mortimer, Thomas, P., Ludema, Kenneth, C., "The Effects of Deicing Salts
      on Road Injury Rates, Tire Friction, and Invisible Wetness," Highway
      Research Record 396, Highway Research Board, Washington,; D. C. (1972).

255.  Perspectives on Benefit-Risk Decision Making, National Academy of
      Engineering, Washington, D. C. (1972).

256.  "Accident Facts,"  National Safety Council, Chicago

257.  Peltzman, S., "The Regulation of Automobile Safety," Journal of Political
      Economy, forthcoming (1975).

258.  "Safe Winter Driving in Ann Arbor," Ann Arbor, Michigan City Hall,  (1971).

259.  "Salt Deicing Cuts Accidents by 75% According to New 116-City Survey,"
      American City,  p. 19,  (1973).

260.  Traffic Operation at Sites of Temproary Obstruction, Paris: Organization
      for Economic Cooperation and Development, (1973).


Legal Implications

261.  "Federal Environmental Legislation and Regulatiions as Affecting
      Highways," Research Results Digest 25, National Cooperative Highways
      Research Program, Highway Research Board, Washington, D. C. (1971).

262.  Kelley, James P., "Hunt vs. the State of Iowa," Law No. 123796, 3rd
      Judicial District, Crawford County, Iowa (1974).

263.  "Analysis by the Legislative Reference Bureau: Statutes 86.37, 86.38,"
      Legislative Reference Bureau - 6581/1, Madison, Wisconsin  (1973).
                                      114

-------
264.  "Analysis by the Legislative Reference Bureau 1: Statutes 36.218,
      84.53, 114.025," Legislative Reference Bureau - 6580/1, Madison,
      Wisconsin, (1973).

265.  "Information and Data with Respect to Department's Responsibility in
      Wells and Water Supplies," New Hampshire Department of Public Works and
      Highways, (1964).

266.  U.S. Congress, Senate, Committee on Interior and Consular Affairs,
    '  Subcommittee on Water and Power Resources, "Saline Water Program;
      Hearing on S.1386," 93rd Congress, First Session (1973).

267.' U.S. Congress, Senate, Committee on Interior and Consular Affairs,
      Subcommittee on Water and Power Resources, "Salinity Control Measures
      on the Colorado River, Hearing on S.1908, S.2940, and S.3094,"
      93rd Congress, 2nd Session (1974).


General Reference Material

268.  Ackerman, S.R., "Used Cars as a Depreciating Asset," Western Economic
      Journal, 11:436^474 (1973).            '

269.  Ackerman, William C.,  "Minor Elements in Illinois Surface Waters,"
      Technical Letter 14, Illinois State Water Survey, Urbana, Illinois  (1971).

270.  Andrews, Richard A., "Economies Associated with Size of Water Utilities
      and Communities Served in New Hampshire and New England," Water Resources
      Bulletin, 7:5:905-912 (1971).

271.  "Automobile Facts and Figures," Automobile Manufacturers Association,
      In., (1974).

272.  Bennett, W.B., "Consumption of Automobiles in the United States,"
      American Economic Review, 57:841-849 (1967).

273.  Boiteux, M.," L'Amortissement-Depreciation de Autombiles,"
      Revue de Statistique Appliguee, 4:57-72 (1956).

274.  Burdick, George E., Lipschuetz, Morris, "Toxicity of Ferro and Ferricyanide
      Solutions to Fish and Determination of Cause of Mortality,"  American
      Fisheries Society,  78:192-202 (1948).

275.  Cherner, Morric, "Property Values as Affected by Highway Landscape,
      Developments," Highway Research Record 53, Highway Research Board,
      Washington,  D. C.,  (1963).

276.  Chow, G. C.,  Demand for Automobiles in the Unites States: A Study
      in Consumer Durables,  Amsterdam: North Holland,  (1957)

277.  Cramer, J.S., "The Depreciation and Mortality of Motor Cars," Journal of
      the Royal Statistical Society, 121:18-59 (1958).
                                       115

-------
278.  Harraeson, Robert, et. al., "Quality of Surface Water in Illinois,
      1966-1971," Bulletin 56, Illinois State Water Survey,  Urbana,  Illinois,
      (1973).

279.  International Shade Tree Conference, Inc.,  "Shade Tree Evaluation,"
      2nd revised edition, edited by Clarence Lewis, Urbana, Illinois  (1970.

280.  Larson,  T.E., "Mineral Content of Public Ground Water Supplies in
      Illinois," Circular 90, Illinois State Water Survey, Urbana,
      Illinois (1963).

281.  Moench,  A.F., Visocky, A.P., "A Preliminary 'Least Cost1  Study of
      Future Groundwater Development in Northeastern Illinois," Circular 102,
      Illinois State Water Survey, Urbana, Illinois, (1971). ;

282.  NADA Official Used Car Guide, National Automobile Dealers Used Car
      Guide Company, [n.d.]

283.  Patterson, Alan,  "Testing a New Approach to Determining the Monetary
      Value of Urban Shade Trees," (mineographed),  (1974).

284.  "Public Water Supplies," New Hampshire Water Supply and Pollution
      Control Commission,  (1974).                            ;

285.  "Report of Routine Chemical and Physical Analyses of Public Water
      Supplies in Massachusetts," Massachusetts Department of; Public Health,
      Division of Environmental Health, Boston, Massachusetts  (1973).

286.  Schicht, R.J., Moench, Allen, "Projected Groundwater Deficiencies  in
      Northeastern Illinois, 1980-2020," Circular 101, Illinois State  Water
      Survey,  Urbana, Illinois  (1971).

287.  Scott, John B., Saunders, M., "The American City Survey of Deicing Salt-
      An Analysis of Salt Usage in U.S. Municipalities above 25,000 Population,"
      Municipal Government Marketing Report No. B6-1172, The American  City
      and Municipal Index,  (1972).

288.  "Survey of Salt,  Calcium Chloride and Abrasive Use in the United
      States and Canada for 1973-1974," Salt Institute, Alexandria, Virginia,
      (1975).

289.  "Survey of Salt, Calcium Chloride and Abrasive Use in the United States
      and Canada for 1969-1970," Salt Institute, Alexandria, Virginia,  (1970.

290.  "Survey of Salt, Calcium Chloride and Abrasive Use for Street and
      Highway Deicing in  the United States and in Canada for 1966-1967,"
      Salt Institute, Alexandria, Virginia  (1967).

291.  Taylor, Floyd B., Our New  England Water Supply, New England Public Health
      Association, Portsmouth, New Hampshire,  (1974).

292.  "Chemical Analyses  of Public Water  Systems,"  Texas State Division of
      Health, Division of Environmental Engineering, Austin, :(rev. ed.)  (1974).

                                      116

-------
293.   "Water Analysis for Fiscal Year 1972-1973,"  Utilities Department,
      Treatment Division, City of Ann ARbor,  Michigan [n.d.]

294.   "1970 Water Resources Data for Massachusetts,  New Hampshire,  Rhode
     .Island and Vermont:. (1)  Surface Water Records; (2)  Water Quality
      Records," U.S. Department of the Interior Geological Survey,  Boston,
      Massachusetts, (1971),

295.   "1972 Water Resources Data for Massachusetts,  New Hampshire,  Rhode
      Island and Vermont: (1)  Surface Water Records; (2)  Water Quality Records,
      U.S. Department of the Interior Geological Survey, Boston, Massachusetts,
      (1974) .

296.   Wykoff, F., "Capital Depreciation in the Post-War Period: Automobiles,"
      Review of Economics and Statistics, 52:168-172 (1970).


Maintenance Procedures and Regulations

297.   "Memoranda Concerning the City's Use of Salt for Snow and Ice Control-
      Environmental Considerations, Research, Recommendations, etc.," Ann
      Arbor, Administrative Environmental Committee, the Mayor's Committee
      on Natural Resources  (1970).

298.   "Article V(a) Tow Away Zone Regulations," Department of Public Works,
      Brookline, Massachusetts.

299.   Cohn Dr. Morris M., Fleming, Rodney R., Managing Snow Removal and
      Ice Control Programs,  A collection of papers presented at the Annual
      North American Snow Conferences 1969-1973, American Public Works
      Association, Special Report 42, (1974).

300.   Cross, Seward E., "Snow Removal Regulations and Enforcement,"
      Department of Highways and Traffic, Washington, D. C., Paper presented
      at American Public Works Association Snow Conference, Chicago, Illinois,
      (1971).

301.   "Maintenance Manual: Sections 5-290-295," Department of Highways,
      Idaho,  (revised) (1966).

302.   Keyser, J. Hode, "Deicing Chemicals and Abrasives: State of the Art," "
      Highway Research Record 425, Highway Research Board, Washington, D.C.,
      (1973)..

303.   Mammel, Fred, Rothbart,  Harold, "Recommendations on the Use of Salt as
      an Ice Control Agent on City Str.eets," Administrative Environmental
      Committee, Ann Arbor, Michigan, (unpublished memo)  (1970).

304.   "Snow and Ice Control,"  Maintenance Manual, Massachusetts Department of
      Public Works, Boston, Massachusetts, [n.d.]

305.   Mellor, Malcolm, "Snow Removal and Ice Control," Cold Regions Science
      and Engineering, Part III, Section A3B, U.S. Army Cold Regions Research
      and Engineering Laboratory, Hanover, New Hampshire  (1965).
                                      117

-------
306.  Minsk, L.D., "Survey of Snow and Ice Removal Techniques," Technical
      Report 128, U.S. Army Cold Regions Research and Engineering Laboratory,
      Hanover, New Hampshire, (1964).

307.  Murray, Donald M., Eigerman, Maria R.,   A Search: New Technology for
      Pavement Snow and Ice Control,  Environmental Protection Technology Series,
      EPA R2-72-125. Environmental Protection Agency, Washington, D.  C.  (1972).

308.  Picardi, Leo D., "Snow Regulations: Real or Unreal ?" Department of
      Public Works, Brookline, Massachusetts, Paper presented at a North American
      Snow Conference, (1970).'

309.  Richardson, David L., Manual for Deicing Chemicals;  Storage; and Handling,
      Environmental Protection Technology Series, EPA-670/2-74-033, Environmental
      Protection Agency, Cincinnati,  Ohio (1974).

310.  Richardson, David L., et.  al.,  Manual for Deicing Chemicals Application
      Practices, Environmental Protection Technology Series, EPA-670/2-74-045,
      Environmental Protection Agency, Cincinnati, Ohio (1974).

311.  Snow Removal and Ice Control Research,  Special Report 115, Highway
      Research Board, Washington, D.  C. (1970).

312.  "The Snowfighter's Salt Storage Handbook," Salt Institute, Alexandria,
      Virginia (1968).

313.  "The Snowfighter's Handbook," Salt Institute, Alexandria, Virginia (1967).

314.  "Symposium on Snow Removal and Ice Control Research," Highway Research
      Circular 103, Highway Research Board, Washington, D.  C.; (1969).

315.  Minimizing Deicing Chemical Use, National Cooperative Highway Research
      Program, Synthesis of Highway Practice  24, Transportation Research Board,
      Washington, D. C. (1974).


Salt in the Atmosphere

316.  Warner, P.D., et. al., "Effects of Street Salting on Ambient Air
      Monitoring of Particulate Pollutants in Detroit," Paper presented at
      the 6th Central Regional Meeting, American Chemical  Society, Detroit,
      Michigan, (1974).

317.  Antler, M., J. Gilbert, "The Effects of Air Pollution on Electric
      Contacts," Journal of Air Pollution Control Association,  13:943-950,
      (1963).

318.  IEEE Working Group, "A Survey of the Problems of Insulator Contamination
      in the United States and Canada Part I," IEEE Trans,  on Power Apparatus
      and Systems, pp. 2577-2585, (1971).
                                      118

-------
319.  Kimoto, I., T. Fujimura, and K. Naito, "Performance of
      Insulators for Direct Current Transmission Line Under Polluted
      Condition," IEEE Trans, on Power Apparatus and Systems,
      May/June 1973, 943-950.

320.  Lambeth, P.J., "Pollution Performance of HVDC Outdoor Insulators,"
      Paper No. 77, September 1966, Conference on High Voltage D.C.
      Transmission, 372-374.

321.  Stensland, G.J., unpublished data for atmospheric deicing salt
      measurements in Pennsylvania in 1972.

322.  Stensland, G.J., "Numerical Simulation of the Washout of Hygrossopic
      Particles in the Atmosphere," Ph.D. Dissertation, Meteorology
      Department, Pennsylvania State University and Technical Report
      327-73, Center for Air Environment Studies, Pennsylvania State
      University, University Park, Pennsylvania, 1973, p. 145.

323.  Stensland, G.J., unpublished data for Troy, New York atmospheric
      deicing salt levels in 1974 and 1975.

324.  Stensland, G.J., "The Flow of Deicing Salt into the Atmosphere,"
      Rensselaer Polytechnic Institute, May 1975 (Unpublished Paper).
Additional References

325.  Jodie, James B., "Quality of Urban Freeway Stormwater," M.  S.
      Thesis, University of Wisconsin-Milwaukee (1974).

326.  :".Report of Routine Chemical and Physical Analyses  of Public Water
      Supplies in Massachusetts," Massachusetts Department of Public Health,
      Division of Environmental Health, Boston, Massachusetts (1973).

327.  "Deicing Salts, Their Use and Effects," NACE Publication 3N175,
      pp. 9-14, (1975).

328.  Schroeder, H.A., Nason, A. P., Tipton, I. H., and  Balassa,  J.  J.,
      Essential Trace Metals in Man: Zinc.  Relation to  Environmental
      Cadmium.  Journal of Chronic Diseases, 20, 179 (1967).

329.  Fatula, M.I., The Feequency of Arterial Hypertension Among  Persons
      Using Water with an Elevated Sodium Chloride Content.  Sovetskaia
      Meditsina 30, 134 (1967).

330.  Feaver, Douglas B., "Four Bridges to be Restored," The Washington
      Post, Washington, D. C., Sept. 15, 1975.

331.  Shellenberger, David E., "The Road Salt Problem:  A New Analysis,"
      Brookline, Massachusetts, 1975.
                                     119

-------
                               APPENDIX A

                  GUIDELINES FOR ASSESSING ALTERNATIVES
The purpose of this appendix is to provide the reader with some very
basic guidelines for evaluating alternative methods of snow and ice
control.  It is likely that many readers who are responsible for winter
maintenance may have already performed equivalent evaluations many
times before.  However this appendix serves to point out some of. the
factors which must be considered in trying to reachri a decision.

The foremost idea to be remembered is that the budget for winter main-
tenance is not the only constraint on the problem.  The ideal solution
would provide maximum safety and time savings while minimizing a total
cost function.  The total cost function would consist not only of the
cost for snow removal, but also of the cost for vehicle, highway,, utility,
vegetation and water damage.  However, as demonstrated in Sections 4
and 5, the development of a total cost function is impossible because
of the difficulty in assigning costs to human health degradation from
water pollution and to vegetation damage.  Factors such as these may
be used to impose additional constraints on the problem, rather than be
included in a cost function.  For example, to do this a community could
impose the constraint that salt could not be used above a set amount
on all highways within or bordering on a watershed area.

A second factor to consider is the requirement for bare pavement.
Representatives of the community should help provide guidelines as to
the importance of keeping various highways bare.  Although there is
certainly a time savings in keeping the highways bare, the link between
bare pavement and safety has not been proven.  Therefore, it is important
to obtain input from the community on their concern for convenience
versus their concern for the damage that results from salt.  As pointed
out earlier, under some circumstances the desired level of bare pave-
ment may not be possible because of other constraints such as water
pollution.

Once the level of bare pavement and all other constraints have been
determined, the highway maintenance department should make an estimate
of the probable reduction in salt use and the equivalent increase
(if needed) in other activities to achieve the required level of bare
pavements and to meet the other constraints.  (Currently the safest
activities to increase are plowing and sanding).  The highway engineers
should attempt to assess all local cost factors as well as possible
                                     120

-------
(as has been done on a general level in Sections 4 and 5).  Assuming
that the effect of salt reduction is linear (a simple but not unreasonable
assumption given the findings in Section 5), cost of salt damage for
both the old and new situation can be estimated.  As best as is possible,
the cost analysis should consider the reduction in cost of damage to
water supplies, vegetation, vehicles, highway structures, utilities,
and any other elements unique to the community.  This reduction should
be compared to the possible increased cost of alternative snow removal
procedures and the possible increased cost of loss time.  All additional
costs of the alternatives, such as other types of damage or spring clean-
up of sand, must be included.

It is especially important that such an assessment be undertaken with
the support and assistance of community representatives.  In addition,
if there are state highways passing through the town or if there is a
water source within the town that supplies other communities, it will be
necessary to bring state or other community representatives into the
decision process so that all environmental factors can; be included in
the analysis.  It should not be the sole responsibility of the highway
department to make such a decision since the community has many subjective
factors at stake, such as water quality, highway aesthetic value and
property values, vehicle corrosion, and taxes for highway damage.
AN EXAMPLE

The following example is supplied to demonstrate how an assessment might
be made as a practical matter.  This example is in no way meant to
represent a typical community situation, but the simple approach used
should help pave the way for communities to perform their own analysis.

Let us examine for an entire winter season the case of a hypothetical
town which has 20,000 families, a total population of 60,000, 25,000
vehicles, and 150 miles of two-lane highways.  There are no state
highways passing through the town and the town does not supply any
water outside its borders.  All of the water supplies are wells, both
public and private.  Approximately half of the vehicle.corrosion damage
from salt is attributable to the use of salt in the town (the remaining
damage resulting from use of the vehicles outside the town.)  Therefore,
average vehicle damage from town salt has been set at $15 per vehicle.
(see Section 5.4 for justification of a $30 cost per vehicle.)

Under the current winter policy, there is moderate to heavy use of salt,
sand, and plowing.  A majority of the wells .in the town are showing
dangerous levels of sodium, ranging from 30 to 100 mg/1, with the average
level at 60 mg/1.  The town has decided to undertake an evaluation of
an alternative.  The people of the town are concerned about their water
and are willing to sacrifice some bare pavement to improve the water.
The highway maintenance engineers feel that they can produce approximately
the same level of bare pavement under most winter conditions (except
                                    121

-------
possibly freezing rain or other special weather situations*)  by  tripling
the plowing and increasing sand use fivefold in exchange for a 50%
decrease in the salt use.  The highway department and the community
leaders have agreed to notify the community of the policy change through
the news media and with prominent signs along the highways and at entry
points into the town.  Figure A-l shows the comparison of the proposed
Policy B to the current Policy A.                  .        :

While Policy B shows a tremendous community savings over Policy A, it
is important to note that any change that might occur in safety and
time savings has not been accounted.  These two factors are subjective
in nature and they should be given careful evaluation by the highway
engineers and community representatives.  With proper public education
and planning the importance of these factors can be minimized even if
the same level of bare pavement cannot be maintained.
 *  However,  these  conditions might even be handled by reserving heavy salt
 for the  occasions and using even less salt under normal circumstances.
                                    122

-------
                              Table   A-l

               Cost Comparison of "Two Snow Removal Policies
                                Policy A

                                       Cost
                               Policy B

                                      Cost
Salt use per two-
lane mile

Total salt use

Total applied salt
cost @ $20 per ton

Plowing cost

Total sand use

Total applied sand
cost @ $4 per ton

Cost of clean-up
of sand
                           20 tons
3,000 tons
2,000 tons
60,000


50,000



 8,000


 5,000
      Total Snow Removal Budget    $123,000
Corrosion cost per
vehicle attributed
to  salt used in  town

Total  cost of vehicle
corrosion
  $15
            375,000
                                                  10 tons
          1,500 tons
10,000 tons
                                    30,000
                                   150,000
                                    40,000
                                    25,000
                                  $245,000
           $7.50
                      187,500
 Damage  to  5 bridges   $500 per bridge   2,500   $250 per bridge  1,250
 attributed to  salt
 Utility corrosion
 costs

 Average Na+ content     60  mg/1
 of all water supplies
                                         500
                                                                250
                         30 mg/1
                                                  1%
 Percent of population    5%
 affected which should
 use bottled water*
 *While this cost may not be  incurred directly,  it is  certainly less  than
 the actual cost incurred in  terms of health degradation.
                                    123

-------
                            Table  A-l (continued)
                 Cost Comparison of Two Snow Removal Policies
Cost of bottled water
at $.10/liter  and  3  liters per
day per person
      Total Damage Cost
      Total Cost to Community
Policy A
       Cost

      328,500


     $706,500

     $829,500
Snow Removal Budget Increase     $122,000
Damage Cost Decrease             $451,800
Net Cost Savings to Community    $329,800
Bolicy B
       Cost

       65,700
     $254,700
     $499,700
                                   124

-------
                              APPENDIX B

                      DEPRECIATION OF AUTOMOBILES
Previous economic studies of used-car prices indicate that a constant
exponential decay model fits the data well*.  Here some of the underly-
ing causes of the depreciation of automobiles are examined and the
separate contributions of certain factors including salts in the environ-
ment are estimated.  We begin with a model of used-car pricing.

Ackerman has developed an economic model of used-car prices based upon
widely.accepted principles of capital theory.  In her approach, the price
of an automobile of a given vintage, K, can be expressed as the discounted
present value of its remaining services.
   (1)
         P(K)   =
         where :
                   K    =  present.age of car
                   T    =  age of scrappage
                   x    =  age
                   r    =  discount rate
                   S(x) =  services provided by car of age x
                   P(K) =  price of car of age K

Differentiation of equation (1) with respect to K yields equation (2)
   (2)
         P'(K) =  -S(K) + rP(K)
which indicates that the rate of price 'change for a car can be broken
into two components, the flow of services and the opportunity cost of
capital invested in the car.  Equation two may be rearranged to obtain
the service function:

   (3)    S(K)  =  -P'(K) + rP(K)          continuous time version

or   (31) S(K)  =  -AP(K) + rP(K)/(l+r)   discrete time version
*  See studies by Ackerman  (268), Bennett  (272), Boiteux  (273), Chow  (276),
Cramer (277), and Wykoff  (296).
                                    125

-------
In order to estimate the service function it is necessarv to mak<= some
explicit assumptions about the time profile of services.  Ackerman chose
to model services as falling at a constant exponential rate with age.
   (4)   S(x)

        where:
                = hP(0)e
                        -ax
                         = constant
                  P(O)   = price of car when new
                  a      = constant rate of exponential decay of car
                           services
substituting  (4) in the expression for used-car prices, (1), one obtains
  (5)   P(K)
     T
=  |hP(0)e
                          -ax -r(x-K)
                                     dx
The price of cars of age K relative to the price of new cars is:
   (6)   P(K)/P(0)
                        he
                          rk
                              T
                                 -(a + r) x
                          -h
                              K
                          a + R
                                -)  (e
                          dx

                    rK -(a + r)T
                                                    -aK,
                                                 - e
As T, the age of scrappage, approaches infinity this expression can be
simplified since the value of  erK~(a + r)T
                                                 be zero in the limit.
Thus:
  (7)   P(K)/P(0)
                     Be
                       -aK
            where B
  h
~a 4- r
Equation (7) is the familiar result that used-car prices decline at a
constant exponential rate.  It may be estimated in the least squares
format by converting to logarithms:
  (8)
        In P(K) - In P(0) = In B - aK
For a given make and production year, one needs price statistics over a
span of several years.  Equation ,(8) is then estimated by least squares,
the coefficient a is the estimate of the constant rate of decay.
AGE DISTRIBUTION OF CARS

The estimation of the total annual costs attributable to accelerated
automobile depreciation because of deicing salts assumes an average
car price of $1,500.

The $1,500 figure is obtained by taking the average new car price of
$4,200 and a decay rate of 25% per year in price.  The proportion of
automobiles of each vintage still remaining registered can be obtained
from R.L. Polk & Co data.  It indicated the proportion of each vintage
is as follows:
                                   126

-------
  Age
Proportion
   -  1
   -  2
   -  3
   -  4
   -  5
   -  6
   -  7
   -  8
   -  9
   - 10
10 - 11
11 - 12
12 - 13
13 - 14
over 14
    .08
    .12
    .11
   . .10
    .09
    .09
    .08
    .07
    .06
    .05
    .05
    .03
    .02
    .01
    .04
                    127

-------
                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
1. REPORT NO.
   EPA-600/2-76-105
                              2.
                                            3. RECIPIENT'S ACCESSION«NO.
4. TITLE AND SUBTITLE
      AN ECONOMIC ANALYSIS OF THE ENVIRONMENTAL IMPACT
      OP HIGHWAY DEICING
                                            5. REPORT DATE
                                             May 1976 (Issuing Date)
                                            6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
     Donald M.
     Ulrich F.
                                                           8. PERFORMING ORGANIZATION REPORT NO.
Murray
W. Ernst
9. PERFORMING ORGANIZATION NAME AND ADDRESS
     Abt Associates Inc.
     55 Wheeler Street
     Cambridge, Massachusetts 02138
                                            10. PROGRAM ELEMENT NO.
                                             1BC611
                                            11. CONTRACT/
                                                             68-03-0442
                                                            NO.
12. SPONSORING AGENCY NAME AND ADDRESS
     Municipal Environmental Research Laboratory
     Office of Research and Development
     U.S. Environmental Protection Agency
     Cincinnati, Ohio  45268
                                            13. TYPE OF REPORT AND PERIOD COVERED
                                              Final '8/74 to  7/75	
                                            14. SPONSORING AGENCY CODE

                                                  EPA-ORD
15. SUPPLEMENTARY NOTES
     Hugh Masters,  Project Officer,  FTS  342-7541
16. ABSTRACT

This study involves  an analysis of the cost of  damages that result from the  use of
salt (sodium chloride and calcium chloride) on  highways to melt snow and ice.   A large
literature search  and several surveys were carried out in order to determine the types
and extent of damages that have occurred.  The  report contains over 320 references.

An in-depth analysis was performed on all of  the  data obtained.  The major cost
sectors examined were:  Water supplies and health,  vegetation, highway structures,
vehicles, and utilities.  For each of the sectors  a cost estimate was developed.  The
total annual national cost of salt related damage  approaches $3 billion dollars or
about 15 times the annual national cost for salt purchase and applicsition.   While  the
largest costs result from damage to vehicles, the  most serious damage seems  to  be  the
pollution of water supplies and the degradation of health which may result.   It is
particularly difficult to assign costs in this  latter area and therefore the estimate
may substantially  understate the actual indirect  costs to society.

These findings indicate that the level of salt  use should be reduced,,  -The amount  of
the reduction should be determined on the basis of local conditions.
17.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                              b.lDENTIFIERS/OPEN ENDED TERMS  C.  COSATI Field/Group
     Deicers
     Snowstorms
     Ice  Control
     Economic Analysis
     Sodium
     Chlorides
     Water Pollution
                                Salt
                                Stormwater Runoff
                                Environmental Impact
                                Snow Control
13B
18. DISTRIBUTION STATEMENT
     Release  to Public
                                              19. SECURITY CLASS (ThisReport)
                                                Unclassified
                                                         21. NO. OF PAGES
                                                              138
                                              20. SECURITY CLASS (Thispage)
                                                Unclassified
                                                                        22. PRICE
EPA Form 2220-1 (9-73)
                                            128
                                                                    *U.S. GOVERNMENT PRINTING OFFICE: 1978— 757-140/6833

-------