vxEPA
fiowimisor 1B33
Analysis of
the Risks and Benefits
of Seven Chemicals
Used for Subterranean
Termite Control
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ANALYSIS OF THE RISKS AND BENEFITS
OP SEVEN CHEMICALS
USED FOR SUBTERRANEAN
TERMITE CONTROL
NOVEMBER, 1983
OFFICE OF PESTICIDES AND TOXIC SUBSTANCES
OFFICE OP PESTICIDE PROGRAMS
ENVIRONMENTAL PROTECTION AGENCY
401 M Street, S.W.
Washington, D.C. 20460
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TABLE OF CONTENTS
PAGE
INTRODUCTION ' 1-1
IDENTIFICATION AND REGULATORY
HISTORY OF CHEMICALS IN THE
TERMITICIDE CLUSTER II-l
THE COSTS AND BENEFITS OF
SUBTERRANEAN TERMITE CONTROL III-l
RISK ANALYSIS IV-1
RISK/BENEFIT ANALYSIS ' V-l
CONCLUSIONS VI-1
BIBLIOGRAPHY VII-1
APPENDIX 1
Physical and Chemical Properties
of Termiticides
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CHAPTER 1
INTRODUCTION
This paper responds to the concerns expressed in the General
Accounting Office (GAO) report "Need for a Formal Risk/Benefit
Review of the Pesticide Chlordane."
In August, 1980 the GAO summarized its investigation of the
adequacy of the Environmental Protection* Agency*1 s (EPA)
regulation of pesticides used in and around the home. During
this review, the GAO concluded that underground application of
pesticides to control termites, may pose unreasonable risks to
man and the environment. The GAO report specifically cited
problems the United states Air Force has had with contamination
in military housing where Chlordane had been applied for termite
prevention or control. "
The GAO report concluded that the EPA should conduct a
Rebuttable Presumption Against Registration (RPAR) review of
Chlordane to determine whether the potential risk of the termite
•use outweighs the benefits of this use. In support of this
conclusion, the report cites the National Canter Institute's
finding that Chlordane causes cancer in laboratory mice, and
the Air Force incidents showing airborne concentrations of
Chlordane in the living quarters of homes built on slab with
heating/cooling ducts in or under the slab previously treated
with Chlordane.
The Agency responded to the GAO report in September, 1980. In
the response, entitled "Response to GAO Report Need for a Formal
Risk/Benefit Review of the Pesticide Chlordane", EPA agreed with
GAO's finding that there is cause for concern about the use of
chlordane for termite control in some treated structures.
Exposure from the termite-control use of chlordane was not
anticipated at the time of the 1974 decision to cancel all
other uses of chlordane.
However, the Agency stated that an RPAR review of chlordane
would not be the best approach to the problem. Although chlordane
is the most widely used termiticide, several other compounds
are also registered for this use, and some are similar in
structure and effects to chlordane. Therefore, the same problem
now associated with chlordane could occur with some or all of
the other compounds.
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The Agency proposed a comparative risk/benefit analysis of the
^terraiticides as a cluster. This approach results in a more
efficient use of Agency resources than cheraical-by-cheraical
RPAR proceedings and it identifies those termiticide chemicals
requiring further regulatory action. Moreover, this -approach
would ensure that the Agency would not take regulatory action
against a pesticide only to have the market replace it with a
more hazardous pesticide.
The major objective of the terraiticide p-roject'"is to identify
and assess the health risks to man associated with the use of
the termiticides as well as the benefits derived from their use.
The chemicals included in the cluster aVe those currently
registered for subterranean termite control: chlordane, heptachlor,
aldrin, dieldrin, lindane, pentachlorophenol, and chlorpyrifos.
Once the potential risks and benefits are discussed, and compared,
further actions, regulatory-and non-regulatory, are identified
to ensure that the concerns raised by the GAO investigation
are adequately addressed.
This report is composed of five chapters in addition to this
introduction, Chapter I. In Chapter II the termiticide chemicals
are identified and a synopsis of the EPA's refulatory actions
on each chemical is presented. Chapter III is a discussion
of the subterranean termite and the costs and benefits associated
with its control. This information on current control practices,
benefits of control, and economic scenarios of possible regulatory
options was compiled by the Agency's Benefits and Field Studies
Division, Office of Pesticide Programs.
Chapter IV summarizes the data on the health effects and human
exposure associated with the termiticides. Data on the possible
health effects of the cyclodienes - chlordane, heptachlor, aldrin,
dieldrin - are presented together because of the similarity
of these chemicals. The data for the remaining termiticides
are presented for each chemical individually. The summaries
of the health effects data are based upon a report entitled
"An Assessment of the Health Risks of Seven Pesticides Used for
Termite Control" developed by the National Academy of Sciences,
August, 1982 as well as other published reviews. Exposure data
were taken from the open literature and unpublished data were
obtained from the Departments of the Air Force, Navy and Army.
Chapter V presents a summary of the health risks and benefits
associated with the use of the termiticides and the final
chapter, Chapter VI, presents the Agency's conclusions and
recommendations.
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CHAPTER II
IDENTIFICATION AND REGULATORY HISTORY OF
CHEMICALS IN THE TERMITICIDE CLUSTER
Identification
The chemicals included in the termiticide cluster are those
currently registered with the Agency for subterranean termite
control. A list of the common names along with the chemical
names of these pesticides is presented below:
Common Name
Chlordane
Heptachlor
Aldrin
Dieldrin
Lindane
Pentachlorophenol
Chlorpyrifos
Chemical Name
1,2,4,5,6,7,8,8-Octachloro-
4,7-methano-3a,4,7,7a-tetra-
hydroindane
1,4,5,6,7,8 ,8a-Heptachloro-
3a ,4,7 ,7a-tetrahydro-4,7-
methanoindane
* «
1,2 ,3 ,4 ,10 ,10-Hexachlcro-
1,4 ,4a,5,8,8a-hexahydro-
1,4 ,5 ,8-dimethanonaphthalene
1,2 ,3 ,4,10 ,10-Hexachloro-
6,7-epoxy-l,4,4a,5,6,7,8,8a-
octahydro-1,4,5,8-dimethano-
naphthalene
Hexachlcrocyclohexane
same as common name
o,o-Diethyl o- (3,5,6-trichloro-
T-pyridyl) pEbsphorothioate
The chemical structure of each termiticide is displayed in
Table II-l. Chlordane, heptachlor, aldrin, and dieldrin are all
chlorinated cyclodiene pesticides. Because of the structural
similarity of the cyclodiene pesticides, the behavior of these
chemicals in the environment and associated health effects
are similar. Lindane and pentachlcrophenol are also chlorinated
hydrocarbons. Chlorpyrifos is an organophosphate pesticide and
thereby, is structurally different from the other terraiticides.
A complete listing of the physical and chemical properties of
the termiticides is presented in the Appendix to this document.
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TABLE II-l
CHEMICAL STHUCTUHE OF TERMITICIDES
CIILOHDANE
ci a H
IIEPTACHLOR
ALDRIN
CI
DIELDItlN
M CI •*
LINDANE
PEWTACIIIX)ROPIIENOf.
o r,n6
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Regulatory History
Chlordane/Heptachlor
1947 - Chlordane first produced commercially in the
United States.
1953 - Commercial production of heptachlor reported in the
United States.
4
March 18 , 1971 - EPA Administrator*announced that an active
internalreview was being initiated on a number of pesticide
products including those containing chlordane and heptachlor.
November 26 , 1974 - A Notice of Intent to cancel all registered
uses of heptacnlor and chlordane, except for subsurface
ground insertion for termite control and dipping of roots
and tops of nonfood plants, appeared in the Federal Register.
July 25, 1975 - EPA Administrator issued a Notice of Intent
to suspend the registrations of certain pesticide products
containing heptachlor and chlordane.
November, 1977 - Cancellation proceeding's continued until
11/77 at which time EPA and Velsicol Chemical Corporation
(registrant) entered into settlement negotiations.
March 6, 1978 - Final cancellation order putting into effect
, terms of settlement was issued.
Aldrin/Dieldrin
1948 - Aldrin and dieldrin synthesized in laboratory.
1951 - Commercial production registered in United States.
March 18, 1971 - EPA Administrator announced issuance of
appropriate notices of cancellation of aldrin and dieldrin.
August 2, 1974 - A Notice of Intent to suspend the registration
of'certain pesticide products containing aldrin and
dieldrin was issued. The use to control termites was
continued.
October 18, 1974 - EPA Administrator announced ail pesticide
products containing aldrin or dieldrin were suspended and
the production for use of all such pesticide products is
prohibited. Subsurface ground insertion for termite control,
dipping of non-food roots and tops, moth-proofing by
manufacturing processes in a closed system uses were
allowed to continue.
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Lindane
Early 1950's - Pesticide products containing lindane are
federally registered.
February 17, 1977 - Position Document 1; Notice of
Rebuttable Presumption Against Registration (RPAR) was
issued. Terraiticide use was not considered in this review.
June, 1980 - Position Document 2/3 in RPAR process was
issued-fermiticide use was not considered in this review.
Pentachlorophenol
1930's - Use as wood preservative began.
1950 - Commercial production in United States reported.
October 18 , 1978 - Position Document 1; Notice of Rebuttable
Presumption Against Registration (RPAR) was issued.
Termiticide use was not considered in this review.
January, 1981 - Position Document 2/3 in RPAR process was
issuedtOnly wood preservative use of pentachlorophenol
were considered in the wood preservatives RPAR PD 2/3;
no discussion of penta as a soil termiticide was included
in the PD 2/3.
Chlorpyrifos
1979 - Dow Chemical Co. obtained state/local need registration
(24-C) from EPA for use of chlorpyrifos in subsurface
termite control.
August, 1980 - Conditional registration granted for general
use as a termiticide.
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CHAPTER III
THE COSTS AND BENEFITS OF SUBTERRANEAN TERMITE CONTROL
Subterranean Teraites; The Nature of the Bea3t
Subterranean termites belong to a number of .species in three
genera in the United States. Generally, the genera Reticuliterates
and Coptotermes are considered the subterranean tenaites of
economic importance, but the dampwood termites of the genus
Zootermopsis may also be included. The most common pests
are species from the genera Reticulite'rmes. The genus Cop tote rmes
are subterranean termites but are able to sustain colonies
without soil contact, if there is moisture in the wood.
Termites are social insects like ants, and some bees and
wasps. A colony is made up of several castes, each with
specific functions within the colony.. A complete colony
consists of a pair of primary reproductives or supplementary
(secondary) reproductives and two non-reproductive castes,
known as workers, and soldiers. The primary reproductives
are darkly pigmented, ant-like winged termites andj are most
commonly observed. In North America, they are usually seen
in the spring when swarming to establish new colonies.
After the swarming flight, males and females pair off and
seek suitable nesting sites. After mating, the queen begins
egg-laying. Only a few eggs are laid the first year, and about
six weeks pass before the eggs hatch. The primary pair cares
for the eggs and the early growth stages of the nymphs, and
also maintains the colony. Gradually, as the nymphs increase
in size and number, castes are formed. - .
The workers maintain and feed the colony. Workers are the
damage-producing caste, destroying wood while tunneling for
food. The soldiers have larger head capsules and powerful
mandibles that enable them to protect the colony. If
supplementary reproductives develop, the growth of the colony
accelerates. A colony started by a single pair of primary
reproductives, develops three to four years before the first
winged reproductives are seen.
Caste regulation is accomplished by an intricate system of
hormones or pheromones. Termites engage in a large amount of
fraternal feeding, or trophallaxis, and almost incessant grooming.
In doing so,, they transfer the hormonal chemicals that maintain
the colony's social cohesiveness. Pheroraones are believed to
inhibit or allow development of members of one sex or the
other, and to regulate the numbers of each caste.
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Generally, subterranean termites must maintain contact with
the soil. They are susceptible to dessication and need the
protection of the soil for moisture. As noted earlier,
exceptions occur rarely in Reticulitermes but more often in
Coptotermes and Zootermopsis species, which can maintain
colonies in constantly dampened wood. Subterranean termites
can become a problem any time they encounter moist, warm soil
containing sufficient food, either wood or other material
containing cellulose. Termites range between the 40°F annual
mean isotherm north and south of the equator. In most
centrally-heated buildings, termites can 'feed all year. In
unheated buildings located in the cooler extremes of the
termites' range, feeding is reduced or may cease entirely
during the winter. In such instances the termites may remain
in the nest deep in the soil. However, termites may be spread
inside previously infested lumber and building materials
above this isotherm. Colonies can then maintain themselves
in soils under modern, centrally heated structures.
The Consequences of Termites
The Damage
Termites feed on the cellulose in plants and p^Lant materials.
In natural habitats this is beneficial, in that the termites
degrade dead plant materials to their original elemental
state. On the other hand, when termites feed on man-made
structures, they can be extremely destructive and must be
controlled. Like most wood-destroying insects, subterranean
termites primarily attack processed wood in use.35 The U.S.
Department of Agriculture has estimated that throughout the
U.S., 46 million dwelling units are subject to termite attacks
annually.35 xne damage caused by wood-destroying insects is
responsible for major economic losses throughout the United
States. Damage caused by subterranean termites accounts for
an estimated 95% of all the termite damage in the U.S.35
The Costs
No national data base has been compiled and published on the
costs of subterranean termites. Several estimates of the
annual national cost, ostensibly including both the loss due
to termite damage and the cost of control, appear in the
literature. These estimates range from S100 million to $3.5
billion. Ebeling's estimate of 5500 million is the most
frequently quoted figure.35
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One measure of the cost of subterranean termite damage is the
cost of termite control and damage prevention. The amount
people are willing to spend to prevent possible termite damage
is a lower-bound estimate of their expectation of termite losses.
In a 1979 USDA report, Richard Smythe and Lonnie Williams
used the state records of a few states to estimate numbers of
wood-destroying insect treatments during 1970 and their cost
in 1976 dollars., These estimates were for single family
dwellings in 11 southern states with high rates of termite
infestation.35 ' . *
The estimates derived by Symthe and Williams indicate that
nearly 440,000 treatments for subterranean termites were
performed in 1970. Of the total, 323,000 were remedial
treatments and 115,000 were preventive or pretreatment. In 1970,
an estimated $130.2 million (1976 dollars) was spent by owners
of single dwelling homes to "prevent and control subterranean
termite infestation. The costs incorporated into this estimate
include: $79.4 million for remedial treatments, $13.8 million
for pretreatments and $37.0 million for contract renewal .or
damage insurance. The cost estimate could be further increased
by an estimated $33.6 million for expenses of damage repair
done by persons other than those in the pest sontroi industry.35
Symthe and Williams have estimated a lower bound for the
value of termite losses in 11 southern high termite infestation
states. In order to construct national estimates one would have to
have similar data on treatment incidence and costs for the
remaining states. Unfortunately, very few states maintain
extensive records of this type. Given this problem, the cost
of potential nationwide termite damage had to be estimated by
extrapolating the Smythe and Williams estimates using national
survey data on pesticide usage. These data came from the EPA
National Household Pesticide Usage Study 1976-77 which
indicated frequency of termite treatments by EPA region
throughout the U.S.4 The extrapolation resulted in an estimated
1.2 million treatments of single family dwellings for
subterranean termites being performed in 1970, at a cost of
$260.3 million (1976 dollars). Including an estimated $102.9
million for contract renewal or damage insurance raises the
total national potential loss estimate in 1970 to $363.2
million. This estimate can be further increased by adding
the estimated $107.6 million for damage repair by someone
other than the pest control industry, bringing the total
potential loss to $470.8 million.
This loss estimate is in 1976 dollars; it can be inflated to
1980 dollars using the Bureau of the Census New One-Family
Houses Construction Cost Index.35 inflating by this index
produces a national potential loss estimate in 1980 dollars
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,o*f S753.4 million annually. The potential loss estimate
presented here would be increased significantly by adding
losses in aultifaraily dwellings, commercial establishments,
public buildings and the major growth in housing stock between
1970 and 1980. Although these national loss estimates for
single family dwellings probably have an upward bias .since
they were developed by extrapolating information for 11
southern high infestation states, this bias is no doubt more
than totally offset by the downward bias resulting from the
exclusion of potential losses in multi-family dwellings,
commercial establishments and public buildings., Velsicol
Chemical Corporation estimates that these excluded losses
appear to be on the order of $250 million annually. However,
it should be noted, that this is an extrapolation of an
extrapolation, based on uneven data from 11 high infestation
level states. Given the available data, 0.75-1.00 billion
dollars per annum appears to be the best available estimate
of the magnitude of the subterranean termite problem in the
U.S. This figure is an estimate based on treatment costs,
cost of renewal and/or damage insurance and the cost of damage
repair. The potential loss estimate represents a lower-bound
estimate of expected termite losses.35
Control Methods
Introduction
There are three basic methods for preventing or controlling
termite infestation. The first method is mechanical alteration.
The second method is chemical control. The third method is
integrated pest management which encompasses mechanical
alteration and chemical control along with several other
methods and non-chemical methods. In addition to these
three control methods, there is also the use of nonwood
construction materials or wood resistant to termite attack.
Mechanical Alteration
Mechanical alteration prevents termite infestation in two
basic ways: reduction or denial of potential food sources,
and dessication of the microhabitat.
Mechanical alteration entails such things as sanitation of
wood scraps during construction, manipulation of microhabitats
by increasing crawl space ventilation to reduce moisture levels
or grading so that water drains properly, and use of construction
techniques that do not allow wood-soil contact.
Termite shields were used more in the past than in recent years.
These shields were thought to aid in protecting against termites
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but instead just allow for better inspection for termites.
Chemical Control
Chemical control occurs on two occasions. The first is
preconstruction treatment or pre-treatment. The second is
post-construction or remedial treatment, and is usually in
response to an identified infestation problem. In either
case, the methods of chemical application are similar.
Notable differences between the two types of application are:
cost (pre-treatment is more economical); e^se of treating a
site rather than drilling and rodding chemicals into the soil
under a structure; and pre-treatment is more thorough and,
thereby, effective. *
Professional Application Practices
This section paraphrases the 1980 Approved Reference Procedures
for Subterranean Termite Control published by the National
Pest Control Association (NPCA) headquartered in Dunn Loring,
Virginia.18 Tne current labeling of termiticide compounds
contains application instructions which are similar, but not
always as extensive as those provided by the NPCA.
« *
Subterranean termites can be controlled or deterred by
impregnating the soil adjacent to a structure with a termite
toxicant. Chemicals to control or prevent termite infestation
are used in three basic ways: soil treatment, foundation
treatment, and wood treatment. Only soil and foundation
treatments will be considered here. Basically, in soil and-
foundation treatment, chemicals are applied along the inside
and outside of foundations; around the bases of supporting
piers, chimney bases, plumbing and conduits; under filled
porches, entrances and terraces; under floor structures
resting on soil or gravel fill; and exposed soil areas under
structures.
One commonly used method of treating inside or outside a
foundation is called trenching. Usually the trench need not
be more than 8 to 12 inches wide, should penetrate the soil
to the top of the footing, and be dug to slope towards the
foundation wall and the top of the footing. Where the tops
of footings are too deep to be easily reached via trenching,
a combination of trenching and grouting or rodding is used to
apply the chemical to the tops of footings. The chemical
is poured along the bottom of the trench. A layer of fill is
replaced, then more chemical is applied, another layer of
fill is replaced, then there is another application, until
the trench is filled. The last layer of treated soil is
covered by a layer of untreated soil or another suitable
barrier such as polyethylene sheeting. In special cases,
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such as near a well or cistern, the backfill may be treated
elsewhere and returned to the trench. In lighter soils or
along rock ledges, the trench may first be lined with a heavy
polyethylene film to prevent the leaching of the pesticide
away frora the trench and foundation.
Treatment along the inside of foundation walls is basically
similar to the trenching done for treatment outside the walls,
although the trenches need not be as deep or vd.de. In cases
where the soil is covered with concrete', roddiVig or grouting
may be necessary. Trenching is being used less now than in
the past and rodding has increased in -use. Currently,
trenching is typically used in combination with rodding to
prevent runoff. Trenching is also done in low crawl spaces.
Grouting rods are pushed or. driven into the ground along a
foundation. Rods are placed about a foot frora the wall and
driven in at an angle to the top of the footing at one foot
intervals. Pesticide is then pvimped through the rods to the
footing. Often the pumping is concurrent with driving the
rod, to aid in penetration. Less commonly, solid rods are
driven down to about the footing, removed, and the^pesticide
is poured down the holes. The interior of foundation walls
are sometimes treated by rodding, especially if concrete
floors cover the soil. Holes are drilled through the concrete
floor at 18 inch intervals 8 to 12 inches from the wall. The
grouting rod is then driven into the soil below the concrete
floor.
Treatment of fill under filled porches, terraces and slab
entry platforms can be done by tunneling or by drilling, then
injecting or spraying the pesticide. To inspect or treat
such areas, an opening is made in the side of a porch or
terrace, then soil is excavated from against the outside wall
of the foundation. This practice breaks any soil-wood contact,
allows inspection for termite activity and also provides
space for a trench treatment, if one is necessary. Alternatively,
the slab may be drilled vertically or the sides may be drilled
horizontally and the pesticide pumped into the fill under
the slab or inside the porch.
Masonry walls of block, brick, stone, tile or other materials
have voids which provide termites with ready, hidden access
to wooden building members. The principle reason for treating
foundation voids is to place the chemical so it can seep
through cracks or voids to the top of the footing. This
prevents the termites from entering via the faults or voids.
This treatment is administered by drilling holes into each
void of blocks or about every 18 inches of bricks or into the
top of a crack in masonry wall, and then pumping pesticide
into the drill hole so that it can seep downward. Generally,
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the holes are drilled just above grade. After application,
the drill holes and cracks are sealed with mortar.
Another application which appears to be confined to California'
involves surface (spray) treatment of the soil beneath existing
structures. In the past, chlordane, heptachlor, and lindane
were applied as a broadcast spray often under high pressure.
More recently, the California Department of Food and Agriculture
(CDFA) has made regulations concerning spray application of
chlorinated hydrocarbons for subterranean termites more
restrictive. Surface application mus't be made under low
pressure as a perimeter band not exceeding 18 inches and only
when conditions (access) will not permit trenching or rodding.
However, the soil surface treatment issue has not been resolved
in California since there is still considerable discussion on
how restrictions on surface treatment should be enforced.
The term "California Wash_® is now used to refer to any process
where surfaces under a structure are sprayed in treating for
termites. It connotes an over-treatment or drenching of the
soil surface with little concern for contact with the foundation
walls or sub-flooring.
Comparative Efficiency • • A
c. , .. . ^ <»
The efficacy of termiticides is measured by the time over
which the toxic barrier remains effective in resisting
penetration by the termites. The efficacy of a specific
termiticide may vary depending on soil type, temperature,
alkalinity, and weather conditions.
There is very little primary literature on the efficacy of
termiticides. However, nearly all of the truly historic and
current studies have been or are being conducted at the USDA
Southern Forest Experiment Station at Gulfport, Mississippi.
The station has unpublished data indicating 100% effectiveness
for 34 years with chlordane and slightly less with the other
cycledienes. Many compounds have been screened for activity
in controlling termites, Williams indicated data exist
demonstrating about 15 years of 100% effective control with
chlorpyrifos.35 These tests are still in progress.
Dr. Raymond Beal also of the Southern Forest Experiment
Station, informed the Agency that lindane applied at 0.4%
was effective for 11 years.^5 By doubling the rate to
0.3%, effectiveness was only increased by two additional
years. Dr. Seal also indicated that endosulfan, which is not
registered for termite control, was tested at 0.5% and provided
about 10 years control. Increasing the rate of endosulfan to
2.0% made it "hold up for a few years longer".
Numerous insecticides have been under study for many years in
soils in southern Mississippi for protection against subterranean
termite attack.35 of these, aldrin, chlordane, dieldrin, and
heptachlcr applied at various concentrations and rates are still
effective after 17 to 21 years.
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•These tests are still underway and indicate that chlordane
remains an effective barrier for at least 34 years, whereas
heptachlor, aldrin, and dieldrin continue to be effective
after 29 years.. 35 soil residue studies were also conducted
which indicated that the insecticides inoved only a few inches
during 17 to 21 years of exposure to the elements. In practice,
as they are placed in and under buildings, the cyclodiene
termiticides movement, without climatic weathering, appears
to be neg-ligible.
*
In 1972, Seal and Smith published the results of a long term
study which evaluated new compounds in terms of termite
control.35 They studied Baygon®, Dimetllan®, Sevin®, Dursban®,
Strobane®, Diazinon®, Zyton*, and the numbered compounds
GS-12968 and GS-13005. As a result, they said: "Dursban® is
the only insecticide that is still 100% effective after 4
years at both 1 and 2% concentrations in both tests...".
They also concluded: "We know that some of these chemicals
will give at least 4 years of protection against termites...
This is a much shorter time than the 33 years that chlordane
has continued to control termites".
Dr. Raymond Seal reported on test data obtained afCer about
11 years of testing.35 peal said: "We chose insecticides
for field testing after screening chemicals in laboratory
tests. Only those chemicals with .a low mammalian toxicity,
low toxicity to other soil insects, relatively low water
solubility, and a manufacturer willing to market the material
[were chosen] ..." Nine compounds were selected that met
those criteria. These were: GS-12968, methidathion, diazinon,
and dimetilan (Ciba-Geigy Corp.); chlorpyrifos and Zytron®
(Dow Chemical Corp.); and carbaryl (Union Carbide Corp.).
As a result of this study,'Seal concluded "dimetilan, diazinon,
GS-12968, methidathion and Zytron* were ineffective as soil
insecticides. Under a concrete slab, camphechlor, propoxur,
and chlorpyrifos remained 100% effective, for 11 years at the
2.0% rate of application. Of these, chlorpyrifos remains the
most promising new compound to date".
In conclusion, chlordane, heptachlor, aldrin, and dieldrin are
the most effective termiticidal compounds and are comparable
in efficacy.
Integrated Pest Management and Non-chemical Control
An integrated pest management (IPH) approach for termite
protection begins with the design of structures, and continues
through site preparation and construction to maintenance,
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moisture control, environmental modification, inspection, and
judicious chemical treatment. In essence, these measures are
a combination of the mechanical and chemical control methods
already described.
The most promising IPM innovation in termite cont-rol appears
to be the bait-block method of insecticide delivery, which
can be used with conventional toxicants, insect growth
regulators, antibiotics, and other control agents. Among the
more innovative approaches to chemical control using bait-
blocks is the use of the juvenile hormone analog methoprene.
Methoprene is an analog of a naturally occurring insect growth
regulator and, when applied as an insecticide, it disrupts
the development of the insect which* eventually results in
mortality. Methoprene is currently registered for use against
mosquitoes, certain flies, and fleas.^5
A non-chemical alternative to termite control has been recently
announced by The Nematode Farms, Inc. in Pest Control Magazine,
October, 1983. The product is called SPEAR". The active
ingredient of SPEAR" is a Steinernematid nematode which is a
microscopic organism with an appetite .for termites. The
nematodes can search for termites by sensing their body heat,
carbon dioxide, and waste trails. After
-------
hich has been treated is found to be infested within one year
>£ /treatment, retreattnent is performed at no cost to the
jwner. Such guarantees are renewable yearly for an annual
fee. These renewal agreements usually provide for an annual
inspection and retreatment, if necessary.
In some cases, additional guarantees are offered. Depending
on the type of structure and the type of treatment performed,
the pest control firm may offer a guarantee against structural
damage for a'one-year period. These damage guarantees are
available only if a retreatraent 'guarantee* is in effect.
These guarantees apply only to termite damage and commit the .
pest control firm- to repair all termite-producing structural damage,
This sort of guarantee is also renewable on an annual basis.
The Cost and Pricing Structure of the Termite Control
Industry .
Table III-l presents a breakdown of variable costs for the
termite control industry. This breakdown of costs is based
on data provided by three leading pest control companies.
The fee charged for treatment is based primarily on t^he amount
of time (labor) required to do the treatment, *The amount of
*ime required to-perform a termite treatment is a function
f both the'mode of application and the area Clinear feet) to
e treated. The mode of application, in turn, is determined
by the type of structure (e.g., slab, crawl space, etc.). To
simplify computation of the treatment charge, most termite
control companies use a pricing schedule.
1 i>
Wages, equipment, vehicles, chemicals, other direct costs,
in addition to overhead and profit margins are factored into
the dollar charge per linear foot presented in the schedule.
Some companies convert linear feet into a time factor before
referring to the pricing schedule, while the others have
already accounted for this conversion in their schedule.
Comparative Cost-Effectiveness of the Registered
* Termiticides
Background and Market Preference
For more than 25 years, foundations and soil beneath ho'uses
have been treated with cyclodiene insecticides (chlordane,
aldrin, dieldrin, and heptachlor) to control termite colonies
and to prevent future infestations. Currently, chlordane is
the most widely used insecticide for subterranean termite
control, followed by heptachlor. Before 1974, chlordane
competed closely with aldrin for the major share of the
market.25 Generally, 55% of the market went to chlordane,
while aldrin accounted for about 40%. The remaining portion
was primarily taken up by heptachlor. Following EPA's
111-10
-------
TABLE III-l
Variable or "Direct" Costs of Termite Control Industry Expressed as a
Percentage of Total Termite Control Revenue
I tan
Labor (wages)
Chenical
Equipment (punping units,
hoses)
Vehicles (includes maintenance)
Damage Claims
Other (miscellaneous expenses,
uniforms, insurance,
taxes)
of Total Revenue a/b/
6-7
2-5
7-13
1-3
10-20
Based on chemical prices prior to the 60 percent increase in the price of
chlordane in the fall of 1982.
Infonnaticn source: Orkin Pest Control, Termini* International, Inc.,
Western Termite and Pest Control
III-ll
-------
cancellation of most of aldrin and dieldrin uses, Shell
Chemical Company discontinued the manufacture and sale of
both compounds in the United States. One of Shell's major
customers, Termini*, a aajor structural pest control applicator,
purchased the remaining supply of technical aldrin and continued
to formulate aldrin products for about a year. From 1975 to
1976, Amvac Chemical Corporation synthesized aldrin for
Tenninix from available intermediates, but these materials
eventually ran out. Currently, Terrainix relies <^n Shell
International (U.K.) for its supply of technical aldrin.
Terrainix imported aldrin in 1977 and 1978>, but aldrin lost
its price competitiveness and was not imported in 1979 and
1980. Between 1980 and 1981 chlordane costs increased
significantly, which improved aldrin1s competitiveness.
There is little evidence of usage of the other chemicals '
registered to control subterranean termites, with the exception
of heptachlor. Heptachlor is typically used in combination with
chlordane and has limited use as a single active ingredient
tenniticide. Dieldrin was never used to any significant
extent in the past, primarily because of its high cost. The
major uses of lindane are as a seed treatment £nd for1 control
of various species of wood inhabiting beetles, but a limited
quantity is applied for termite control by a few pest control
operators (PCO1s)(primarily in California). Although registered
to be used in the soil for controlling subterranean termites,
pentachlorophenol (penta) is rarely applied in this manner.
Penta is used as a tenniticide only for special applications,
such as wood icipregation when termites are associated with
decay. A concentrated formulation of chlorpyrifos for
subterranean termite control has been developed by Dow Chemical
Company. Although registered with EPA in late 1980, the
product has only recently been introduced for the 1981 market
season. There was some use of chlorpyrifos (Dursban®) for
subterranean termites in California under 24-C registration
(late 1979) from about June 1980 to December 1980. Currently,
the chlcrpyrifos termiticide is more expensive than the
chlorinated hydrocarbons, and provides an option to PCO's
and their customers. Table 111-2 presents production and
usage information on the termiticides.
Costs of Termiticides
Table III-3 presents the comparative costs of the termiticides
in current use. These are bulk user prices. From the table,
it can be seen that chlordane, heptachlor, and aldrin are
virtually identical in cost and significantly cheaper than
either chlorpyrifos or lindane. Dieldrin is not included in
the cost table because it is currently not available or
111-12
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Table II1-2
Production and Usage of Tenniticide Chemicals
Chemical
Producer
Amount of Chemical
Used in
Termite Control (1980)
Most Comon
Formulated Products
Used in
Termite Control
Camtents
Chlordana
Velsicol
Chemical
Corporation
(Ibs./ai)
Approx. all of 10
million pounds used
for termite control
C-100 (Bibs/gal)1
C-50 (4 Ibs/gal)1
8EC (8 Ibs/gal)»
Termide* (4.2 Ibs.
chlordane/yal;
2.1 Ibs. heptachlor/
gal.)2
Most widely used insecticide
for subterranean termite
control in 19BO.
Largest quantity of chlordane
initially distributed to
Region IV.
Hepatchlor
Velsicol
Chemical
Corporation
Approx. 90%
(1-2 million Ibs)
H-60 (2 l/21bs/gal)3
Termide** (2.1 IbsV
heptachlor/ga1;
4.2 Ibs. chlordane/
gal.)
Used in smaller quantities
and on fewer sites than
chlordane.
linported fron
Shell International
Chemical Company
Aldrin Unported fron Aldrin 4-E A^ldrin was not imported in
(4 lb/gal)4 1979-or 19BO.
Aldrin was imported again in
1981.
Use as a termiticide aeons to
be increasing in response to
chlordane price increases.
1/Chlordane concentrations are typically diluted with water to obtain a 1.0%/gal. emulsion before use."~~
2/Chlordano-heptachlor mix is diluted with water to obtain a 0.5% chlordane/0.25& heptachlor emulsion. '
3/Heptachlor concentrate is typically diluted and applied as a 0.5% emulsion.
4/Bitulsifiable concentrate is mixed 1 gal. (EC) to 95 gallons of water to form a 0.5% use strength emulsion.
Ht-13
-------
Table II1-2
Production and Usage of Term!ticIda Chemicals
Chemical
Producer
Amount of Chemical
Used in
Termite Control (1980)
Most Cannon
Formulated Products
Used in
Termite Control
Comments
Dieldrin
Shell International
Chemical Company
(Ihs.a.i.)
No production in U.S.
since 1974.
Hot available in the U.S,
and no known consunption
in U.S.
Lindane
Zoecon Corporation 11,000-12,000
No domestic production of
lindane since 1976;
Usage level haa remained
constant for the last 5
yearsj
Few POO's identify lindarta
as preferred termite control
ageqtj
Use apparently limited to few
pest control firms in So.
California}
Most lindans used in termite
control is applied to soil as
surface epray.
Pentachloro-
phenol
Very low percentage of
the 40-50 million Ibs.
produced is used in
termite control
Ko application to soil reported
by PCO'sj
Use limited to specific termite
control problems (e.g., where
termites have been associated
with decay or direct application
to infested wood structures).
111-14
-------
Table
Production and Usage of
rmiticide Chemicals
Chemical
Producer
Amount of Chemical
Used in
Termite Control (1980)
Most Common
Formulated Products
Used in
Termi te Control
Ccmnents
Chlorpyrifos Dow Chemical
Company *
(Ibs. a.!.)
Few thousand Iba.
sold by end of 1980.
(California onlyj
Dow Termiticide^
concentrate 44.4% BC
Dursban^TC 42.09% EC5
In 1979 Dow obtained a state
local need registration (24-C)
for chlorpyrifos to be used for
subsurface termite control
in California.
Conditional registration as
termiticide granted in 1981.
5/Two gallons of concentrate are mixed with 100 gallons of water to yield a 1.0% use strength emulsion.
111-15
-------
TABI£ III-)
Gon|>arat|ve Coala o( Iterwlticlrie
(.1u»ic*l tormildtloii l/ost » Caot/qal. Dilute /Ippro*. Chuaical
|$/9*l.l Dilute Solution Beady-to-Use Solution Coat for Protection
Bpilvalent of
1 gal. cyclmllenesty
($>
(lili r.lim: (1 IX' 10. 00 1.0 O.JO 0.10
/M.lrln 4 rt- 25.00 0.5 0.25 0.25
Hil«i.tiii<>/ 4.2 Uilor. 2U.OO 0.5 0.27 0.27
l^l'l.ujilor 2.1 ll>vta. 0.25
V
(ltlo«vyri(os 4 P.C 6S.OO 1.0 I.JO 2.60
l.iiiliiV! 1 UL 12.00 0.8 0.77 ^ 1.54
^Pf^rott. Ibtal
o( Projection
Bjuiviilent to
1/qal. cyclollenea^^y
($>
5.OO
5.00
5. IK)
12. no
10.94
V
Ki'iur'^ Uvso<1 on tulk unor |>rlonn palil l>y Orkln, Heatern. nnd Itomlnlx In 1981.
•y
A.s:«m:n d>loq»yr ilofl nnl llrvlaiw |x;ralttt 1/2 «a loot] as cyclodleneo.-
£/
cyclulf<»M> dnikioil oost to 6t of total ajipl'cation onta.
'J/
CiMita |ir'.-H«-«a<-l .u >r I'JHl oat lm.il
-------
consumed in the United States and, therefore, current price
estimates are not available. In the past, the cost of dieldrin
was typically higher than the cost of the other cyclodienes,
which contributed to lower dieldrin usage relative to the
other cyclodienes. When the reduced persistance of lindane
and chlorpyrifos is taken in account, cost differences between
these chemicals and the cyclodienes widen still further. If
one assumes that chlorpyrifos and lindane persist half as
long as the cyclodiene termiticides, the chemical cost of the
protection equivalent to that provided by one^ gallon of
cyclodiene tenniticides increases from'$1.30 to $2.60 with
chlorpyrifos and frora $0.77 to $1.54 with lindane.
The application costs of the retreatments required with the
chlorpyrifos and lindane will further expand the cost
differential, from $5.00 with the cyclodienes to approximately
$12.00 with chlorpyrifos and to $10.94 with lindane.
Another factor that would increase the differential on costs
for the application of chlorpyrifos compared to the cyclodienes
is the cost for monitoring the blood cholinesterase level of
applicators before the use of the chemical and on a regular
basis.
As can be seen from this and the previous section, chlordane,
heptachlor, and aldrin are the most cost-effective
chemicals for termite control. Lindane or chlorpyrifos are
alternatives which can be used where use of the other
termiticides is restricted either by the structure's owner
or government regulation.
There appears to be some disagreement within the PCO industry
as to which of the cyclodienes is best in terms of ease of
handling and applicator health effects. On balance, the
choice between the cyclodienes seems to be one of personal
preference rather than documented advantages or disadvantages.
The efficacy of a number of chemicals, not currently used as
termiticides, was previously discussed. While some were
effective, their persistence compares unfavorably with those
chemicals currently in use. Mobay Chemical Company has a
compound, Oftanol*, that was registered as a restricted use
pesticide for control of subterranean termites July 19, 1982.
However, insufficient testing has been done to date to allow
evaluation of its viability as an alternative to the cyclodienes,
It is reasonable to expect that as long as the cyclodienes
remain on the market and/or are relatively inexpensive, the
111-17
-------
outlook for new chemical controls will be bleak because of the
difficulties in finding cost competitive alternatives to the
existing chemicals. There is currently little incentive to
develop new control methods as long as inexpensive, effective
products are available.
Subterranean termites are colonial insects which damage wooden
structures by eating the cellulose in the wood. The estimated
annual cost of this damage to the nation is at least three
quarters of a billion dollars. This estimate is based on
treatment costs, cost renewal and/or damage insurance and the
cost of damage repair. Subterranean termites can be prevented
partially by proper construction methods and design, and by
prophylaxis with terraiticides. When termites do become
established in a structure, they can generally be controlled
with pesticides. The preferred pesticides r considering
price, efficacy, and extended period of protection, are the
cyclodiene pesticides, particularly chlordane or aldrin. While the
extended period of protection is a, major advantage of the
cyclodiene pesticides, current practices in* the field indicate
that treatment with the cyclodienes occurs more frequently
than the 30 plus years of termite control shown by these chemicals.
If, in practice, the consumer is not able to take advantage of
the extended period of protection, then the benefits of the
cyclodienes would diminish. Pest control operators as well as
the financial and real estate .institutions must be aware that
frequent retreatments with cyclodienes are not necessary unless
a reinfestation is found in a structure.
111-18
-------
CHAPTER IV
RISK ANALYSIS
An analysis of the risks associated wi.th the^use of the
chemicals in the termiticide cluster considers information on
health effects in combination with an assessment of the
exposure likely to occur from this registered use. The first
part of this chapter consists of a discussion of the available
information on the health effects for each of the chemicals.
Chlordane, heptachlor, aldrin, and dieldrin, referred to as
the cyclodienes, will be considered together because of
similarity in chemical structure and associated health effects,
Lindane, pentachlorophenol, and chlorpyrifos will be discussed
individually. The summaries on toxic effects are taken from
extensive published reviews and assessments of the data on
the termiticides, particularly the recently completed National
Academy of Sciences report, "An Assessment £>f theiHealth Risks
of Seven Pesticides Used for Termite Control" (referred to as
NAS report). In cases where a specific study is discussed,
the author of the study is given so that the study may be
identified. However, in most cases the original study was
not reviewed by the Agency, but rather the information was
taken from a secondary source. The secondary source is then
referenced and listed in the bibliography.
The second part of this chapter discusses the information
available on the extent of human exposure to the termiticides,
HEALTH EFFECTS DATA
Cyclodienes - Chlcrdane, Heptachlor, Aldrin, Dieldrin
Acute toxicity information for the cyclodienes is presented
in Table IV-1. Toxicity for the cyclodienes is characterized
by effects on the central nervous system.^5,39,40
Table IV-1
Acute Oral Toxicity Data By Chemical
C_hemi_ca_l Oral LDgj) Value (rats, mq/kg)
Chlordane 335-430
Heptachlor 100-160
Aldrin 46-63T
Dieldrin 38-52
IV-1
-------
Data show that exposure to the cyclodiene terraiticides can
affect the central nervous system in humans and animals.
Symptoms of acute poisoning in man include: dizziness, nervousness.,
convulsions, and loss of coordination.40
Oncogenicity
Carcinogenicity data on the cyclodiene' termiticides have'been
reviewed extensively. Studies have been conducted in several
species of laboratory animals to evaluate the carcinogenic
potential of each of the chemicals. The analyses and
interpretations of the results of these studies regarding
carcinogenic potential vary for each compound and species/strain/sex
of the test animal. Tests conducted in rats were all negative
for chlordane, heptachlorT aldrin and dieldrin. Chlordane,
heptachlor, aldrin, and dieldrin are carcinogenic in mice,
producing liver neoplasms after oral administration of the
chemicals. Data concerning the Carcinogenicity of these.
chemicals in rats are inconclusive.41 The one consistent
result observed is that all four of ,the cyclodienes produce' a
significant increase in the incidence of he'batocellular :
carcinomas in the B6C3F1 strain of mice.15,39,40
The limited human studies with long-term exposure to any of
the cyclodienes have not revealed any consistent or significant
detrimental health effects.
Teratogenicity and Reproductive Effects
The available teratogenicity and reproductive effects data
for the cyclodienes are not as extensive as the Carcinogenicity
data ^and are inconclusive.
In a study (Ingle, 1952) in which rats were fed chlordane in
the diet at 5,10,30, 150, or 300 ppm, one female rat from
each test group was mated at the 24th and 48th week. No
effects on litter size or number were reported by the authors.
Heptachlor, fed to rats in the—diet at 6 mg/kg body weight,
caused a decrease in litter size in a multigeneration study
(Mestitzova, 1967).15
Several studies investigating the teratogenic potential of
aldrin and dieldrin were cited in the NAS report.15 Pregnant
hamsters were given single oral doses of aldrin at 50 mg/kg
and dieldrin at 30 mg/kg on day 7,8, or 9 of gestation
(Ottolenghi e_t a^. , 1974). The authors of the study reported
an increase in fetal deaths, compared with controls, and an
increase in anomalies such as open eye, cleft palate, and
webbed feet. Mice, given aldrin at 25 mg/kg or dieldrin at
15 mg/kg on day 9 of gestation, showed no effect on fetal
survival or weight but some anomalies were noted.
IV-2
-------
In other studies on mice and rats administered dieldrin at
1.5, 3, and 6 mg/kg/day on days 7-16 of gestation, no teratogenic
effects were observed (Chernoff et al., 1975). However, at
6 rag/kg a 41% increase in mortalTty was noticed in rats and
increased liver-to-body weight ratios and decreased weight
gain in mice was observed.1*
4
In a six-generation mouse reproduction study, aldrin and
dieldrin were administered at 25 rag/kg per day in the diet.
The authors noted marked effects in fertility, gestation^
viability, and lactation at 25 mg/kg (Deichmann, 1972).^
Mutagenieity
*«
Data from the tests including the Salmonella microsome assay
and the dominant-lethal test (mouse!indicate that pure
chlordane is negative in all of these test systems but
technical chlordane was mutagenic in Salmonella without
mammalian activating enzymes (Simmon e_t £l. , 1977).15,39
When chlordane was administered in a single <^ose ofi 50 or
100 mg/kg/body weight to Charles River CD-I male mice that
were then mated to untreated females, no dominant lethal
effects were noted in the offspring (Arnold e_t aj^., 1977). 15
In a recent study, chlordane and heptachlor were investigated
for genotoxicity in cells derived from the organ in which
they produce tumors (liver cells). The authors concluded that both
chlordane and heptachlor were negative in the ARL-HGPRT
mutagenesis, which is a sensitive system for detecting mutagenic
potential of various compounds (Telang e_t Q. , 1982).*4
Additionally, heptachlor was found not to be mutagenic when
tested in several strains of Salmonella typhimurium with and
without a rat-liver microsomal activation system (Marshall et al.,
1976). In a dominant-lethal test rats were fed a diet of
heptachlor at 1 or 5 mg/kg. Significant number of resorbed
fetuses and increases in the numbe'r of abnormal mitoses were
absorbed in the second and third generations (Arnold et al.,
1977). 15,39 *
The results of several studies indicate that dieidrin was not
mutagenic in several strains of Salmonella typhiniurium with
or without liver activation systems. One study reported that
dieldrin was mutagenic in two or three strains of Salmonella
typhimurium without activation (Majumber et al., 1977).15
IV-3
-------
Lindane
The acute oral LDsg value for rats is between 125-230 mg/kg/body
weight. Earliest signs of lindane toxicity include: headache,
dizziness, and vomiting. Other symptoms are: diarrhea,
hypothermia, hyperirritability, incoordination, and
convulsions.15f 36
Oncogenicity
Several carcinogenicity studies have been conducted on lindane.
In a study similar to those conducted on the cyclodienes,
groups of 50 B6C3P1 mice of each sex were fed 80 or 160 ppm
lindane in the diet for SO^weeks (NCI, 1977) . The results
indicated a significant increase in the incidence of hepatocellular
carcinoma in the males of the low-dose group compared to the
controls. However, no significant difference in the incidence
of hepatocellular carcinoma was found in the high-dose group
when compared to the controls. The authors of the study
concluded that lindane was not carcinogenic ^Ln mic%.15
In another study, 400 ppm lindane in the diet was fed to CF1
mice (Thorpe and Walker, 1973). Increases in liver tumors
were observed in both male and female mice.15
Groups of 50 Osborne-Mendel rats of each sex were fed lindane
in the diet for 80 weeks; 236- or 472 ppm for males and 135 or
270 ppm for females (NCI,1977). No significant increase in
the incidence of tumors was observed in any of the test
groups.. I5
Teratogenicity and Reproductive Effects
Several studies have been conducted on the teratogenic and
reproductive effects potential of lindane. Lindane does not
appear to cause teratogenic or reproductive effects. Fetal
effects at or above the dosage that causes general maternal
toxicity have been observed.
In a three-generation rat study, lindane was fed in the diet
at 25, 50, or 100 ppm (Palmer e_t aJL , 1978). No reproductive
effects were observed and no increase in malformations were
observed.15 When lindane was given orally at 5, 10, or 15
mg/kg/body weight to rabbits on days 6-18 of gestation and
to rats on days 6-16 of gestation, no teratogenic effects
were observed.4&
In another study, lindane was given orally to female rats at
0.5 mg/kg (Naishtein and Leibovich, 1971). Disturbances in
the estrus cycle and diminished reproductive capacity were
observed.40
IV-4
-------
Mutagenicity
Mutagenicity was not a concern at the time Position Document 2/3 .
was developed by the Agency. The mutagenicity data base for lindane
is not complete, but available studies suggest little mutagenic
activity, if any.36
Pentachlorophenol
The oral LD$Q of pentachlorophenol for rats is 146-175 mg/kg.
Symptoms of intoxication include accelerated respiration,
vomiting, increased body temperature, tachycardia, neurorauscular
weakness, and cardiac failure. Similar symptoms of loss of
appetite, respiratory difficulties, hyperpyrexia, sweating,
dyspea, and coma have been reported in humans.40
In the Notice of Rebuttable Presumption Against Registration
(October 18, 1978), the Agency cited-three studies concerning
the possible oncogenicity of pentachlorophenpl. rhnes et al.
(1969) administered by gavage 46.4 mg/kg pentachlorophenol to
mice on days 7 through 28 of age, followed by 130 ppm
(17 mg/kg/day) in the diet for 2 years did not increase tumor
incidence over control animals. Boutwell and Bosch (1959)
applied 0.3% dimethylbenzanthracene in benzene as an initiator
to the shaved backs of mice. As a promoter, a solution of
20% penta in benzene was applied similarly twice weekly for
15 weeks.34
These papers were reviewed by the Agency's Carcinogen Assessment
Group and were found to be negative with respect to oncogenic
effects of penta. However, since that time several other
studies pertinent to the oncogenic potential of commercial
pentachlorophenol and its contaminants became available. The
National Cancer Institute reports two bioassay studies dealing
with the possible carcinogenicity. of two isomers of
hexachlorodibenzo-p-dioxin (HxCDD), a contaminant of
pentachlorophenol. The results of one study, on the dermal
application of HxCDD to mice were negative. In the second
study, rats and mice were given oral doses of HxCDD ranging
from 1.25 mg/kg/week to 10 mg/kg/week. Under the conditions
of this study, HxCDD increased the incidence of benign and
neoplastic liver tumors in mice of both sexes and in female
rats.34
Teratoqenicity and Reproductive Effects
Embryotoxic and fetotoxic effects were observed in Sprague-
Dawley rats given pure or commercial grade pentachlorophenol
at dosage levels of 15 mg/kg/body weight or greater (Schwetz et
al. , 1974). In another study by the same author, no effects
IV-5
-------
on neonatal survival and development were observed in rats fed
3 mg/kg of pure pentachlorophenol prior to Bating, during
mating, during gestation and lactation. At 30 rag/kg , a
reduction in body weight was observed among adult rats as
veil as & decrease in neonatal survive! and growth. 15
Mutagenicity
Pentachlorophenol did not induce sex-linked recessive lethals
in Drosophila melanogaster. ^°
Chlorpyrifos
The oral LDso of Chlorpyrifos for rats is between 82-245
ag/kg. Acute data in rats suggest that Chlorpyrifos is
absorbed through the skin in acutely toxic amounts. A study
in humans indicates that absorption through the skin is limited
to only a small fraction of the applied dose. ^ Symptoms
of Chlorpyrifos poisoning include: nervousness, giddiness,
headache, blurred vision, weakness, nausea, cramps, diarrhea,
and discomfort in the chest.10,15
Oncoqenicity
Two long-term feeding studies have been conducted to
investigate the effects of Chlorpyrifos. In a 2-year study,
groups of rats and dogs received dose levels of up to
3 mg/kg body weight/day Chlorpyrifos. Dosages of 0.1 mg/kg/day
or less had no effect on plasma and red-cell cholinesterase
activity in rats and no effect was observed in dogs at
0.03 mg/kg body weight/day. Higher dietary concentrations of
Chlorpyrifos caused significant decreases in cholinesterase
activity (McCollister et aU , 1974). 1S
In another study, CD— 1 mice were^given Chlorpyrifos in the
diet at 0.85, 6.72, and 15.8 ppm for 105 weeks (approximately
0.05, 0.5, and 1.5 rag/kg body weight/day) (Warner et al. ,
1980). No significant effects were observed in the treated
group. Tumors and other lesions were observed in treated
and control groups but no tumors appeared to be related to
the treatment of Chlorpyrifos.15
IV-6
-------
Teratogenicity and Reproductive Effects
No teratogenic effects were observed in pregnant CF-1 mice
administered chlorpyrifos by gavage at 1, 10, or 25 mg/kg on
days 6-15 of gestation (Deacon e_t a 1. , 1980)'. At 25 ag/kg
severe maternal toxicity and fetotoxicity was observed
and a decrease in plasma and red-cell cholinesterase was
reported at all dosages. In a repeated experiment, a decrease
in cholinesterase activity was noted at 1 and 10 mg/kg.^
Mutagenicity
Mutagenicity tests in several strains of Salmonella typhimurium
and Escherichia coli were negative.15
EXPOSURE DATA
Available evidence of potential human exposures to the
termiticides is presented in the discussion ythat fallows.
Distinct groups of people that could be exposed to termiticides
have been identified: workers engaged in the manufacture of
termiticides; persons who apply termiticides, including
professional applicators and the general public who use
household products which contain these chemicals; and persons
residing in structures which have been treated with termiticides,
Although some exposure data are available for each of the
groups identified above, the information is primarily on
exposure to chlordane.
Human exposure to termiticides has been previously considered
and various exposure levels have been established. The
American Conference of Governmental Industrial Hygienists 1982
(ACGIH) has adopted a Threshold Limit Value-Time 'Weighted
Average (TLV-TWA) of 500 ug/M^ for chlordane in workroom air.
This value can be interpreted as, the maximum level to which
workers may be continuously exposed to chlordane in the
workplace (8 hours/day, 5 days/week) without adverse effect.
The Occupational Safety and Health Administration's (OSHA)
permissable workplace exposure limit is 500 ug/M^.
IV-7
-------
Similarly, exposure levels have -been established for-the other
tenniticides and are listed below:
ACGIH Level • OSHA Level
Chemical (uq/M3) (ug/M^)
" . «
Heptachlor 500 500
Aldrin/Dieldrin 250 * 250
Lindane 500 500
Pentachlorphenol 500 500
Chlorpyrifos 200 -
The exposure analysis that follows considers inhalation and
dermal exposure to these chemicals from their termite control
use. Exposure to these chemicals as a result of other uses
is not considered for the purposes of this discussion.
Although the most widely used termiticides, the cyclodienes,
have not been registered for uses other than termite control
(and certain phase-out uses of chlordane and heptachlor)
since the mid-1970's, these chemicals are very persistent in
the environment. Therefore, other sources of exposure, as a
result of former registered uses is very probable. The
other termiticides, lindane, pentachlorophenol, and Chlorpyrifos
are not widely used for termite control but have numerous
other registered uses. Also, since all of these chemicals.
are available for homeowner use, the additional potential
sources of exposure are difficult to estimate. Therefore,
the exposure estimates do not represent total possible exposure
to any of the chemicals but rather attempt to estimate the
amount of exposure from just the termite control use.
Workers Involved in Manufacture of Tenniticides
The few studies that have been 'conducted to investigate the
occupational exposure to the tenniticides have focused on
exposure to chlordane. The most recent investigation studied
a cohort of 1,403 workers employed for longer than three
months in the manufacture of chlordane and heptachlor at two
plant locations between 1946 and 1976 (Wang and McMahon, 1979).
Data obtained from Social Security records, death records,
and employment records, indicated no overall excess of deaths
from cancer. There was a statistically significant excess of
deaths from cerebrovascular disease but the authors concluded
that these deaths occurred after termination of employment
and were not related to duration of exposure.15
IV-8
-------
Shindell and Associates (1980) continued to study former and
current employees at the two plants of the Velsicol Chemical
Corporation. This cohort consisted of 1,115 people who worked
at the Memphis plant between January, 1952 and December, 1979
and 783 people who worked at the Marshall, Illinois plant
from January, 1946 through December, 1979 „ T^e authors
concluded that the mortality among workers at the Marshall,
Illinois plant was significantly lower than expected while at
the Memphis plant the mortality was lover than expected, but
not significantly so.
There was a statistically significant positive trend in the
standard mortality ratio far cancer deaths in workers with
increasing duration of employment. However, the increase in
standard mortality ratios from one to 20 years of exposure
was not large. The findings among workers who had a minimum
of 20 years of employment were seven deaths from cancer with
6.6 deaths expected; for workers with 10 or more years of
employment there were 14 deaths with 13.6 deaths expected;
and for workers with a minimum of five years employment there
were 16 deaths with 16.5 deaths expected. None of the
individual values has statistical significance. The authors
of the study concluded that there was no evidence to indicate
that current or past workers at Velsicol plants are at an
increased risk for health-related problems. The HAS report
indicates that the results of this epidemiology study suggest
a trend in cancer deaths with duration of employment but
advise that more complete data are needed before firm conclusions
can be reached with regard to the carcinogenicity of
chlordane in humans.15,23
Additionally, a retrospective cohort mortality study to
examine mortality among workers employed in the manufacture
of the chlorinated hydrocarbon pesticides was initiated by
the National Institute of Occupational Safety and Health
(NIOSH).6 The intent of the study was to examine the mortality
of workers employed in plants where the following pesticides
are manufactured: chlordane, heptachlor, DDT, aldrin/dieldrin,
and endrin. Pour U.S. manufacturing plants were selected for
the study and each cohort included all workers employed for
at least six months prior to December 1, 1964. The study
group consisted of 2100 individuals.
The vital status for each of the individuals in the cohorts
was followed up to December 31, 1976. The Standard Mortality
Ratio (SMR) for all causes of death in each cohort was below
the expected level. In one of the plant cohorts (aldrin/dieldrin/
endrin) deaths due to nonmalignant respiratory system disease
were significantly above that expected.
IV-9
-------
The authors stated that the deaths observed due to "all
malignant neoplasms" in each plant were less that the number
expected. Although there were no statistically significant
excesses or deficits in mortality for any specific cancer
site, for the following several sites the observed number of
deaths slightly exceeded the expected number for individual
plants: stomach, esophagus, rectum, liver, iV^phatic
and hematopoietic system. There was a deficit for respiratory
cancer in one plant. ^
The overall conclusions of the study investigators were that
due to the small number of workers included in the study, the
statistical power does not support a conclusion that no
association exists between*cause-specific mortality and
employment at the study plants. The authors stated that the
primary reason for the small cohort numbers is due to the
rapid turnover at the plants and, therefore, most workers who
were hired left before completing six months of employment.
Professional Applicator Exposure ' t •-*•'•
The National Pest Control Association (NPCA) has provided
estimates of the number of personnel engaged in structural
pest control work. These estimates are presented in
Table IV-2.
Table rv-2
Number of Personnel Engaged in Structural . • "•
Pest Control Work
Total
Number of Personnel Personnel Specializing
Engaged in General in Control of Wood
Year pest Control Destroying Organisms
1974 31,000 8,600
1979 . 42,000 11,524
1980 36,500 13,500
Information on potential exposure levels for applicators of
termiticide chemicals is limited to a study conducted jointly
by Velsicol Chemical Corporation and the California Department of
Pood and Agriculture. This study determined potential chlordane
exposure to applicators and inhabitants in six houses of two
types: crawl space and slab construction. The treatments
were conducted by commercial pest control operators. Exposure
was measured by monitoring the concentration of chlordane in
IV-10
-------
the applicator's breathing zone and by attaching cloth patches
to the applicator's coveralls. Air samples were taken as
follows: air inside and outside applicator's respirator,
air during and after application, air samples taken 24 and
48 hours after application, and 7 and 30 days after application.
The levels of chlordane detected from the cloth patches and
gauze material worn on the applicator's overalls were similar
for the slab and crawl space treatments. The levels of
chlordane from the slab treatment ranged from 0.005-1.70 ug/M^
and for the crawl space 0.019-2.90 ug/M2.3,12
Nonprofessional (Homeowner) Applicator Exposure
«
There are no known data on the number of people who use
commonly available products containing the termiticides.
However, EPA estimates that approximately 1.5 million pounds
of these chemicals are sold annually to the general public for
the period 1979-1981. In 1982, 1.4 million pounds of chlordane
were sold. Velsicol forecasts that 600,000 pounds -of chlordane
will be sold for home owner use in 1983.
The National Household Pesticide Usage Study, 1976-1977
provides some information on homeowner usage of chlordane-
containing products. In this study, 8254 households were
interviewed and asked to provide information regarding all
pesticides that they had used or stored during the past year.
The data from this survey pertaining to chlordane are presented
below and provides an indication of homeowner usage. However,
the time period considered in this study preceded the
restriction of chlordane usage to subterranean termite control.
Chlordane ranked fourth among 12 known pesticides observed
most frequently in the study. From the survey, 639 households
reported having used or stored 694 chlordane products within
the previous year. Based on these- data, it was estimated
that 7.7% of the households in the U.S. used or stored
chlordane-containing packages or containers and that over
6.2 million chlordane products were used by 5.7 million U.S.
households. Sixty-five percent of the household use was
application to the lawn, yard or flower gardens; 17.2% application
inside houses; and 14.1% application to vegetable gardens.
IV-11
-------
Residents of Buildings Treated with Teraiticides
Several reports and studies are.available on possible exposure
to residents of tenaiticida-treated dwellings.
U.S. Department of Defense Monitoring program
Department of the Air Force
Airborne chlordane contamination of military housing units
following treatment for tennites was Reported by the Department
of the Air Force in the early 1970's. The first incident
occurred at Wabb Air Force Base, Texas in the spring of 1970.
Twenty-eight air samples from two houses with cardboard duct
work in a concrete slab were analyzed for chlordane. The
concentrations of chlordane ranged from 800 to 1600 ug/H3
initially and from 34 to 180 ug/M3 eighteen days after attempts
to clean the chlordane from the duct work.
A second incident occurred at Wright-Patterson Air Force Base,
Ohio during 1974-19.75. Air samples were obtained 2rom 537
newly constructed houses that had been pretreated with
chlordane. Measurable levels of chlordane were detected in
412 of 537 houses sampled* Concentrations ranged from a
trace (>0.4 ug/M3) to 34 ug/M3.
In October of 1978, two houses at Scott Air Force Base,
Illinois, were monitored as a result of occupant complaints
of odors following subslab injection of chlordane. The chlordane
concentration in these units were 263 and 26 ug/M3. These results
prompted a survey of 11 other units treated in a similar manner
in 1978. Chlordane concentrations ranged from 0.4 ug/M3 to 22 ug/M3
in these units. In 1980, the study was expanded to include ail
498 housing units, 63 of which had no record of termiticide treatment.
Measurable levels of chlordane ranging from a trace O0.2
ug/M3) to 38 ug/M3 were found in 335 out of 435 treated
units (77%). The study investigations concluded that there
was a statistical difference in chlordane levels in units
treated in 1978 as compared to units treated in other years.
These several occurrences of chlordane contamination of houses
prompted the Air Force to conduct extensive tests in houses
throughout the Air Force with a history of chlordaae treatment
and with ducts in or beneath the concrete slab. Two studies
were conducted, the first in 1975 following discovery of the
contamination at Wright-Patterson Air Force Base and the
second following discovery of contaminated houses at Scott
Air Force Base. The 1975 study included only houses with
preconstruction treatment and involved sampling 165 houses at
IV-12
-------
five Air Force bases. Sample results ranged from none detected
(<0.2 ug/M3) to 4.1 ug/M^. A more extensive program was begun
in 1980 which included all houses with a history of chlordane
treatment regardless of the method of application. Approximately
6400 Air Force houses were included in the study. A three-year
program was established with those houses treated by subslab
injection receiving the highest priority .for evaluation.
Second priority for evaluation were those houses that received
preconstruction treatment. Finally, those houses evaluated
in the 1975 study were to be reevaluatetf.
The data from the air samples collected since 1973 in the Air
Force owned houses are summarized in Table IV-3 by house
construction type and type of chlordane treatment. The levels
of chlordane presented in the table represent only the initial
samples collected in houses with potential chlordane
contamination. Specifically, these houses were those chlordane-
treated houses constructed over an enclosed crawl space with
ventilation ducts traversing the crawl space. Based on these
monitoring results, the air in 55% of the unitp of siab or
crawl space construction were found to have n£ detectable
amounts of chlordane, 40% had detectable levels of < 5 ug/M3
chlordane, and 5% had levels of >5 ug/M^ chlordane.T
In a report "Chlordane in Air Force Family Housing: A Study
of Slab-On-Grade Houses, April 1983", the Air Force noted the
difference between measurable air levels in slab houses
treated prior to construction versus houses treated after
construction. An explanation offered for this difference was
that preconstruction ground treatment provided a considerably
more uniform ground application than that of post-construction.
Furthermore, it was stated that high pressure injection
techniques used in post-construction treatment may have
resulted in an uneven distribution or concentration of chlordane
under the slab. Additionally, the possibility exists that the
pesticide could be forced into cracks in the duct or slab
during high pressure injection.
Based on the monitoring data collected, the Air Force noted
•that chlordane intrusion into slab houses peaked during cold
weather months when heating systems were utilized. The warm
air passing through the ducts heated adjacent to chlordane
treated surfaces increased the vaporization of chlordane. In
houses with poorly sealed ductwork, chlordane vapors entered
the ducts with subsequent distribution throughout the
ventilation system.
Air Force investigators have noted that modifications to the
ventilation system in slab houses decreased airborne chlordane
concentrations 93-97%. (Livingston, J.M. et al., 1981) 30.
The modifications consisted of sealing all~subslab ducting
and relocating ventilation ductwork inside the house.
IV-13
-------
TABLE IV-3
,'
Summary of Chlordane Air Monitoring Program of Housing Units
Located at U.S. Air Force Installations
Type
Construction
Slab
Crawl-Space
Total
Type Total
Chlordane Units
Treatment Sampled
Subs lab
Injection - Post 987
Construction
Subslab Ground
Application - 2818
Precons truct ton
Trench Ing- Post 12
Construction
No treatment
records , some
treatment 210
suspected
Crawl-space soil
application- post
construction
(surface or
trenching) 749
4776
Non-
detectable
255
2145
10
177
37
2624
(54.9%)
IV-U
Number of Chlordane Air Samples
<2uq/M3 <5ug/M3 <10ug/M3 >10ug/M3
493 190 37 12
481 152 31 9
11 00
*
^ 24 8 1- 0
360 206 98 48
1359 557 167 69
(28.5%) (11.7%) (3.5%) . (1.4%)
-------
For example, at Scott Air Force Base slab ducts were sealed
and relocated overhead in 39 houses where chlordane levels
were found to be >_ 4 ug/M3. The interiors of the houses
were repainted. A resampling of air levels showed a decrease
in airborne chlordane levels of 93-95% in the reducted units.
As a result of the monitoring data collected and published in the
previously cited April, 1983 report, the' Air Force concluded
the following: airborne chlordane concentrations are not
likely to exceed 5 ug/M3 in sub- or intxraslab ducted houses
that have only been treated prior to construction: airborne
levels of chlordane in the living area of sub- or intraslab
ducted houses is likely to occur following pesticide treatment
of these dwellings using high pressure injection techniques;
sub- or intraslab ventilation ductwork is the source of
chlordane intrusion into the living area of slab houses; and
sealing sub- or intraslab ducts and relocating the ventilation
ducting overhead will reduce chlordane levels in family
housing living areas by 93-97%.
The Air Force recommended for their installations that "family
housing units with sub- or intraslab ventilation ducting
should not be treated for termites using injection techniques
unless absolutely necessary to save the structure"; and "if
sub- or intraslab ducted houses have been treated for
subterranean termite control, airborne chlordane concentrations
in the house should be measured to determine if relocating
the ventilation system ductwork inside the structure is necessary".
U.S. Department of the Navy
The Naval Facilities Engineering Command, Department of Navy
conducted a monitoring program for airborne levels of
terraiticides in Navy and Marine Corps family housing units.
This program was conducted during the 1981-1982 heating season
in nearly 4,000 family housing units which were identified as
units whose construction included sub- and intra-slab heating
or cooling ducts, including single and multi-family units.
As of October 18, 1982, 3957 buildings located at thirty-two
installations across the United States had been sampled and
the samples had been analyzed for levels of chlordane,
heptachlor, aldrin, and dieldrin.
The results from the initial sampling are presented on the next
page. In most units where detectable levels of a termiticide
were found, the termiticide was chlordane since it was the
probably the termiticide used the most. Some samples from
units also contained heptachlor, aldrin and dieldrin. However,
the data are only available in aggregate form and are not
IV-15
-------
broken down for each chemical. The guideline levels 'used
were the National Academy of Sciences guidelines of 5 ug/M3
chlordane, 2 ug/M3 heptachlor, and 1 ug/M3 aldrin/dieldrin.
Number of Housing Dnits Levels of Termiticides
« v—
3160 (79.9%) Below detection limit
740 (18.7%) Detectable, below NAS
guidelines levels
57 (1.4%) Greater than HAS
guideline levels
As a result of this monitoring effort, the occupants of the
fifty-seven housing units having termiticide levels exceeding
the action levels were relocated.H
Department of the Army
The Department of the Army is conducting a monitoring program
for airborne levels in the 19,741 Army housing units that have
sub- and intra-slab heating and cooling ducts. Of the 3,061
housing units sampled as of June, 1983, 27 units had levels
of chlordane exceeding the 5 ug/M3 HAS interim guideline.
Twenty-three of these twenty-seven units were located at one
installation, and the four remaining units were located on 2
different installations (Smith, Department of the Army, personal
communication).
Non-Military Termiticide Monitoring Studies
Five additional monitoring studies are available. A brief
description of each study and the results are presented in
Table IV-4. Four of the five studies monitored for indoor
airborne concentrations of chlordane, heptachlor, aldrin, or
dieldrin and one study monitored for chlorpyrifos. Houses
of the following types were monitored in these various studies:
plenum, crawl space, slab and combination of crawl space/slab
basement.
IV-16
-------
TABLE IV-4
Summary of Non-Military Termiticide Monitoring Studies
Title of Study
and Author
Types of
Samples Collected
Chemical
Analyzed For
Description of
Owe11i ng Men1tored
Study Results/Conclusions
Pesticide Air, Soil, Blood
Residues in
Mouses Utilizing
Forced Air Plenum
Distribution
Systems, I975i
Colorado
Epidemiology
(Pesticides Studies
Center
Chlordane Houses- treated with
Heptachlor cyclodienes
Dieldrin
6 plenum, 1-3 yrs.old
6 plenum, 9-12 yrs.old
Uouses-Not Treated
3 plenum, 1-3 yrs.old
2 crawl space, 1-3 yrs.old
3 plenum, 9-12 yrs.old
1 crawl si>ace,9-12 yrs.old
6 conventional, crawl space
Dieldrin
(ng/M7!
n.d.-12t)
25-467
g
.7-2
1.0
2-99
2
2-46
Chlordane
(ng/M^
7-3654
12-41
7-16
9,53
12-53
c 39
4
27-1513
Heptachlor
(ng/M^T
3-269
.7-27
.6-6
1,3
2-5
5
7-622
1-3 yrs.old
5 conventional,crawl space
9-12 yrs.old
1-108
-180
3-25
Conclusions
Mean levels of cyclodienes in air higher in samples
fn*n treated plenum houses than air samples collected
fr
-------
TABLE IV-4
Summary of Non-Military Termiticide Monitoring Studies
Title of Study
and Author
Types of
Samples Collected
Chemical
Analyzed For
Description of
Dwelling Monitored
Study Results/Conclusions
Airborne
Concentrations of
Chlorpyrlfos
Monitored in
Buildings During
and After Appli-
cation of Formu-
lation M-4328 for
Control.of Suh-
terranoan Termites.
Dew Chemical Company,
1979,
Air
Chlorpyrifoa
5 Crawl Space Houses
(Georgia)
4 Basement Houses
(California)
Crawl Space Houses - Highest
concentrations found during and
after application in living areasi
.003 mrj/M3 and .002 mg/M*
respectively.
Basement Houses - Highest
concentrations found during and
after application (24 hrs.)
in living areast .037 mg/M-* and
.013 ng/M3, respectively.
Conclusipns - Authors of study
concluded "that airborne
concentrations found in
structures during and after
treatment are believed to be
well below*levels expected
to cause a health concern to
occupants of treated structures.
• I il .11.. j
IV-18
-------
TABLE IV-4
Summary of Non-Military Termiticide Monitoring Studies
Title of Study
and Author
Types of
Samples Collected
Chemical
Analyzed For
Description of
Dwelling Monitored
Study Results/Conclusions
Assessment of
Exposure Pollowing
the Use of Aldrin
as a Termiticide
in Homes, Shell
Research Limited,
Sittingbourne
Research Centre,
December, 1982.
Air
Aldrin,Dieldrin
3 Concrete Slab Houses
(California)
3 Crawl Space Houses
24 Hours After Application
<.04-.27ug/M3 (aldrin)
<.04-.06ug/M3 (dieldrtn)
7-56 Days After Application
<.04-.15ug/M3 (aldrin)
<.04ug/M3 (dieldrin)
24 Hours After Application
.09-7.0ug/M3 (aldrin)
<.04ug/M3 (dieldrin)
7-<66 Days After Application
~*~ •
.05-.55UJ/M3 (aldrin)
<.04-.17ug/M3 (dieldrin)
IV-19
-------
Table IV-4
Sumwry of Non-Military Termitlclde Monitoring Studies
Title of Study
and Author
Types of
Samples Collected
Chemical
Analyzed For
Description of
Dwelling Monitored
Study Results/Conclusions
A Study In So.
California in July
1979 of the Potential
Dermal and Inhalation
Exposure of Applicators
and Other Persons Vt\o
Might Later Enter or
Occupy Areas Treated
with Chlordane Used
Against Subterranean
Termites Under Housest
1979. Maddy et a\,
California Department
of Food and Agriculture
Air
Chlordane
3 Crawl Space Houses
3 Slab Houses
During Application (Lavela in
Living Areas)
Crawli N.D.-.001 mg/fi*
Slab: N.D.
rAfter Application (Levels in
Living Areas)
Immediately After Application
Crawli N.D.
Slabs N.D.
*
24-48 Hours After Application
Crawlt N.D.
Slab: N.Q,
7 Days After Application
Crawlt .OOl-.OOTrog/M3
Slab: ,004-.013mg/M3
30 Days
Crawlt N.D.
Slab: N.D.
IV-20
-------
Table IV-4
Summary of Non-Military Termltlclde Monitoring Studies
Title of Study
and Author
Types of
Samples Collected
Chemical
Analyzed For
Description of
Dwelling Monitored
Study Results/Conclusions
Applicator and Inhabitant
Exposure to Chlordane
During and After Termiticide
Applications in California
Cahill.W.P. and M.K.Stumphy,
1979. (Velsicol Results o£
Study Cited on p. 1V-19.)
Immediately After Application
Crawl: N.n.-.104mg/M3
Slab: N.D.-.0023nq/M3
24-48 Hours After Application
Crawls N.D.-.OB4mg/M3
Slab: N.D.-.0017nq/M3
22 Pays After Application
Crawlt .0010-.064mg/M3
Slab: No samples
IV-21
-------
TABLE IV-4
Sunmary of Non-Military Termitlcide Monitoring Studies
Title of Study
and Author
Types of
Samples Collected
Chemical
Analyzed For
Description of
Dwelling Monitored
Study BeauIta/Concluaions
Termite Control
Produces Low Levels
Chlordane and
Heptachlor in Treated
(louses. Wright, C.G.
and R.B. I,eidy.
Peat Control
Technology, July, 1982
pp.44-45,55.
Air
Chlordane,
Heptachlor
6 Houses Infested with.
Subterranean Termites
Having Crawl Spaces
or Crawl Space/
Slab Basement
Ranges of Mean Values of 1%
Chlordane Product Used -
Inroad lately After Application
through 1 Year Aftert
2.75-5.01 ug/M3
Ranges of Mean Values
After Termidea(.5% Chlordane
and .25ft Heptachlor)
Product Used-Immediately After
Application through 1 Year After?
crflordanet 2.34-5.81 ug/M3
Heptachlort 1.00-1.80 ug/M3
IV-22
-------
CHAPTER V
RISK/BENEFIT ANALYSIS
The purpose of this chapter is to summarize th^ risks and
benefits associated with the chemicals used in subterranean
termite control and to then compare these risks, and benefits
for this use.
Summary of Risks
Health Effects
Data indicate that all of the cyclodiene termiticides cause
central nervous system.effects in humans and animals after acute
exposure. Symptoms include: dizziness, nervousness, convulsions,
and loss of coordination. Lindane has also been shown to
be toxic to the central nervous system to animals aqd humans
after both short and long term exposure. *
The symptoms identified from exposure to pentachlorophenol
include loss of appetite and respiratory difficulties. Other
effects include pathologic changes in the liver and kidneys.
Embryotoxicity and fetotoxicity was observed in the offspring
of rats.
The primary effect noted as a result of an acute exposure of
humans to chlorpyrifos is a reduction in plasma and red-cell
cholinesterase activity. Symptoms include: nervousness,
giddiness, headache, blurred vision, weakness, nausea, cramps,
diarrhea, and discomfort in the chest. All of the cyclodienes
have induced hepatocellular carcinomas in the B6C3F1 strain
of mice. However, this response was not observed in rats.
The results of the carcinogenicity tests in rodents administered
lindane have not been consistenty~with both positive and
negative results reported. The data available for pure
pentachlorophenol and chlorpyrifos do not indicate a carcinogenic
effect. However, technical pentachlorophenol is contaminated
with the carcinogenic dioxin, hexachlorodibenzo-p-dioxin
(HxCDD).
In the recent investigation of the risks of the termiticides
by the National Academy of Sciences (NAS), it was concluded
that available data are insufficient to determine whether
carcinogenesis is the critical biological end-point (health
effect) of concern when humans are exposed to the cyclodienes
and lindane. However, the NAS report did state that available
animal data allow a comparison to be made of carcinogenic
potential for 5 out of 7 pesticides that were tested under
similar experimental protocols and had similar results -
hepatocellular carcinomas in B6C3F1 strain of male mice.
V-l
-------
On the basis of the ED^o» the dosage producing an incidence in
liver tumors 10% above background level, the ranking from
greatest to least carcinogenic risk potential would b® aldrin,
dieldrin; heptachlor; chlordane; lindane. *5.
In the HAS report, it was noted that a^ diraci; comparison of
the carcinogenic potential of chlorpyrifos with the cyclodienes
is not possible. The reason is that the available studies on
the compounds used a different test protocol and a different
strain of mice (cyclodienes used B6C3F strain and chlorpyrifos
used CD-I strain). The authors of the NAS report continued
to point out that if the highest dose in the chlorpyrifos study,
15.8 ppm, and the same experimental conditions were used,
estimates of the proportion of animals that would be expected
to have tumors after exposure to other pesticides could be made.
On this basis, chlordane and lindane would be expected to yield
negative results if tested under the same conditions as
chlorpyrifos and the carcinogenicity potential of chlorpyrifos
cannot be predicted. While it is true that the carcinogenicity
of chlorpyrifos cannot be predicted, the erfects of higher
doses of chlorpyrifos will be depression of acetylcholinesterase.
Therefore, for chlorpyrifos this dosage can be considered
maximum since higher doses would result in survival problems
due to the acute toxieity and cholinesterase depression
effects associated with chlorpyrifos.
Exposure
A discussion of possible health effects provides only half of
the risk assessment of a chemical. The issue of whether or-.
not humans are exposed to termiticides as a result of their"
proper, registered use "must be settled in order to assess Lf
the use of these chemicals poses an unreasonable risk to man.
A level of exposure to any of the termiticides below which .
there would be no biologic effects has not been determined.'
In its August, 1982 report the NAS Committee on Toxicology
suggested interim airborne concentration level guidelines for
five termiticides as follows: chlordane (5ug/M3), heptachlor
(2 ug/M3), aldrin/dieldrin (1 ug/M3), and chlorpyrifos
(10 ug/M3). A guideline was not suggested for lindane because
available data are not adequate to provide a basis for an
airborne exposure limit and because lindane is not currently
used to control termites in military housing. Similarly, a
guideline was not set for pentachlorophenol because of the lack
of definitive data and it also is not now used to control termites
in military housing.
V-2
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In the NAS report, these exposure guidelines for each of the
termiticides were presented for the purpose of providing guidance
in estimating the health risks of these chemicals in military
housing. These exposure limits were based on.health considerations
as well as the judgement of scientists participating in the
NAS study. It should be noted that the MAS interim guidelines
apply to long-tern continuous exposure and the NAS Committee
did not consider short-term exposure guidelines. Therefore,
the guidelines would be applicable to tenaiticide concentra-
tions measured over an extended period such as a year but
not to concentrations measured over shorter periods.
The Agency views the interim levels as useful for guiding
efforts to determine on a ca"se-by-case basis whether particular
individuals in fact face a health risk in a particular
environment. Such a determination would often involve testing
and health monitoring beyond the sampling of air concentrations.
The guidelines will be reassessed once the further toxicology
and air monitoring data are generated and then reviewed by
the Agency. *
The information on exposure to applicators is limited to one
study in which -air monitoring was only done for chlordane.
The results indicate levels ranging from non-detectable to
.073 ug/M-3 of chlordane inside slab and crawl space houses
up to 30 days after application.
The data pertaining to exposure to residents of treated
dwellings also is primarily for chlordane and the majority of
the data were collected in military housing units in dwellings
wth heating/cooling ducts in or below the slab and houses
with crawl spaces. In the aggregate/ military data on the
sub- and intra-slab duct houses and some crawl space houses
indicate that out of 11,794 housing units tested, 320 (2.7%)
had detectable levels of chlordane, heptachlor, aldrin or
dieldrin.
In the most recent study conducted on civilian houses with
crawl space or combination crawl space/slab basement—treated
with chlordane and chlordane/heptachlor, mean levels of
chlordane immediately and up to 1 year after application
ranged from 2.34-5.81 ug/M3. The respective levels for
heptachlor were 1.00-1.89 ug/M3.42
Thus, given the information available to the Agency at this
time, residents of dwellings of certain construction types ma
be exposed to the chemicals used to treat the dwellings for
termite control.
V-3
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Summary of Benefits
Chlordane is the most widely used insecticide for subterranean
termite control. Heptachlor and aldrin are used in much
smaller quantities than chlordane for termite control.
Aldrin, imported in 1981, could capture as much as
25% of the termiticide market in response to chlordane price
increases. To date, there are no known sales or use of
dialdrin in the United States. The use of lindane as a
termiticide seems to be limited to peat control firms in
California. Pentachlorophenol is used only for specific
termite control problems where termites have been associated
vith decay or' direct application to infested wood structures.
It is not used for subsurface applications. A few thousand
pounds of chlorpyrifos were sold in 1980, primarily in
California.
Available data indicate that chlordane is presently the most
effective termiticide. Heptachlor, aldrin, and dieldrin are
comparable in effectiveness. Dieldrin was rarely used as a
termiticide because of its high price.. Chldtpyrif*os seems
to be the most promising new compound. However, to obtain
equivalent, pest control cost is at least twice that of
chlordane/heptachlor/aldrin.
Within the pest control industry, the choice between cyclodienes
appears to be one of personal preference rather than documented
advantages and disadvantages of the individual chemicals.
No national data have been compiled and published on the costs
society has incurred as a result of the subterranean termite.
A number of estimates of the annual national cost, including
both the loss due to termite damage and the cost of control
have been noted in the literature. The most frequently cited
figure is S500 million. The Agency has estimated the potential
cost of termite infestation by extrapolating from data on
control and damage repair costs in eleven states. This
nationwide estimate, inflated to 1980 dollars, is $753.4
million. If multi-family, commercial, and public dwellings
are considered, the estimate is-expanded to $1.022 billion.
In summary, the benefits for the termiti.cides, particularly
the cyclodienes, are very high.
Risk/Benefit
After consideration of the available information on the risks
and benefits for the termiticides the Agency concludes that
the benefits from their use to control subterranean termites
are extremely high.
V-4
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The risk assessment for these chemicals is incomplete because
of the lack of definitive data on the extent of human exposure,
the amount of exposure, and, aost importantly, data on the
critical biological end point (health effect) in humans
exposed to these pesticides. At this time in assessing the
risks and benefits associated with the total national use of
the termiticides based on available data, and considering the
lack of data outlined above, the Agency finds that the benefits
from the use of the currently registered tenaiticide products
outweigh the potential risks. The Agency, recognizes that in
individual cases where tenaiticides were Improperly applied
or misused in treating a residential dwelling, the risks
from exposure to the chemicals nay exceed the benefits.
V-5
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CHAPTER VI
CONCLUSIONS
As a result of the analysis of the information on the risk
and benefits associated with the use of the termiticides,
the Agency has concluded that the benefits, particularly
for the cyclodienes, are very high and the cyclodienes are
the most effective chemicals currently registered for
termite control. The Agency cannot complete a risk assessment
of the termiticides due to a lack of Definitive health and
exposure data.
The information on possible health effects associated with
the use of the termiticides is summarized in Chapter IV of
this document. One major-inadequacy of the existing tenniticide
data base is that it consists only of dietary exposure
studies. In the case of tenniticide use, inhalation is
clearly the route of exposure to be considered in assessing
the risk. Moreover, in the recent tenniticide risk review
conducted by the National Academy of Sciences, it was
concluded that the data were not sufficients© determine
whether carcinogenicity is the critical biological end-point
(health effect) in humans exposed to the termiticides.
The Agency accepts this conclusion and has determined that
additional toxicology data are needed to assess the risks
to humans exposed to termiticides.
Additionally, the Agency has concluded that exposure is
the principal issue in assessing the health risks posed by
the use of the termiticides. The Agency has recently
reviewed monitoring data that showed contamination of living
quarters following termite treatment. The data consist
mostly of contamination incidents in military housing
units constructed with sub- and intra-slab ducts. To a
limited extent, some contamination incidents were also
reported in military housing units with crawl spaces.
Information is not available on the tenniticide treatment
use history for the monitored mi-litary housing units or
for other types of housing structures. Therefore, it
cannot be determined if the tenniticide contamination
problem is confined to houses with sub- and intra-slab
ducts and, possibly, crawl spaces and, if applied properly,
if contamination in these structures will always occur.
However, from the available monitoring data and individual
incidents reported, exposure to the termiticides may occur
in a low percentage of houses of specific construction types.
The risk assessment for these chemicals is incomplete because
of the lack of definitive data on the extent of human
exposure, the amount of exposure, and, most importantly
data on the critical biological end point (health effect)
in humans exposed to these pesticides. At this time in
VI-1
-------
assessing the risks and benefits,associated with the total
national use of the termiticides based on available data,
and considering the lack of data outlined above, the Agency
finds that the benefits from the use of the currently
registered termiticide products outweigh the potential risks.
The Agency recognizes that in individual cases where
tsrmiticides were improperly applied or misused in treating
a residential dwelling, the risks from exposure to the
chemicals may exceed the benefits* ,
* ^
The Agency has developed an action plan to obtain the
necessary toxicology and exposure datea to fully assess the
health risks and determine further regulatory action.
Given the uncertainties with respect to human health effects
and exposure, the immediate short term actions that have been
taken focus on reducing possible human exposure to the
termiticides and obtaining additional information on health
affects and exposure.
Label Improvement Program
The Label Improvement Program (LIP) that is being carried
out by the Registration Division, Office of Pesticide
Programs has resulted in the addition of several statements
to labels of products registered for the control of termites.
These statements are designed to prevent potential hazards
by reducing the possibility of misuse and, consequently,
exposure. A number of statements specifically caution the
application of termiticides near heating ducts, near domestic
water supplies (cisterns, private wells, etc.), and around
structures containing sub-floor crawl spaces.
The majority of registrants have compiled with the LIP.
The Agency is currently notifying the remaining registrants
regarding compliance with the LIP for termiticides.
Restricted Use Classification
Currently, federally registered products containing chlor—
dane, heptachlor, aldrin, dieldrin, lindane, pentachloro—
phenol, and chlorpyrifos are noJ: classified as restricted
use pesticides. That is, products containing the above
listed chemicals are available to homeowners for purchase
and use, and are not required to be applied by certified
applicators.
VI-2
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Six states have already taken regulatory action to restrict
the use of chlordane to application only by certified
applicators or individuals under their direct supervision.
These states are: Connecticut, Hawaii, Massachusetts,
New Mexico (products with concentrations >5%), New Jersey
(effective 12/83), and Vermont.
The Agency has identified restricting the use of the
termiticides as a measure to alleviate possible misuse of
these chemicals and, thereby, reduce human exposure. The
Agency is contacting state regulatory agencies to obtain
information on incidents of misuse that would support the
classification of restricted use. *
Prohibit Use jpf Cyclodienes on Specific Structures
Measures concerning the use of the cyclodiene termiticides
on certain types of structures have already been taken by
registrants and the National Pest Control Association
(NPCA). The manufacturer of chlordane has voluntarily added
to the label the statement not to use chlordane on plenum
housing. NFCA also instructs its membership not to treat
plenum houses with the cyclodienes. Additionally^ NPCA
cautions its members to locate ductwork prior to treatment
of houses with sub- and intra-slab ducts.
The Agency is currently evaluating the measures outlined
above in light of available monitoring data and monitoring
data that is being requested by the Agency.
Concurrent with pursuing the above short-term measures,
the Agency has identified data that are needed to complete
a qualitative and quantitative risk assessment on each of
the._termiticides and determine if additional regulatory
action is necessary.
Toxicology Data
As stated previously, the toxicology data available on the
termiticides consists of animal studies where the route of
exposure is dietary. Inhalation is the route of exposure
of concern in dealing with the problems of termiticide
use. Additionally, the critical biological end point as a
result of exposure to these chemicals cannot be determined
from existing data. Therefore, the Agency is requiring
registrants of termiticides in the cluster considered in this
report to submit the following data under the authority of
Section 3(c)(2)(B) of the Federal Insecticide, Fungicide, and
Rodenticide Act: mutagenicity tests and a subchronic
inhalation study.
VI-3
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The battery of mutagenicity tests would consist of the
following (in vivo activation): host.mediated assay with
bacterial indicator or sex-linked recessive lethal assay
in Drosophila; chromosomal aberrations assay in bone marrow
cells, or a micronucleus test, or a sister-chromatid exchange
teat;'unscheduled DNA synthesis in hepatocytes from treated
rodents; and cell transformation in primary cultures from
treated hamsters. These specific studies -will allow for
an evaluation of mutagenic risk and for assessment of oncogenic
risk for the cyclodienes.
A subchronic inhalation study will provide data on the critical
biological end point after exposure to these chemicals.
The Agency reserves the right to request chronic inhalation
studies pending the results and analysis of the subchronic studies.
Monitoring Data
The Agency is requiring, under the authority of Section
3(c)(2)(B) of the Federal Insecticide,.Fungicide, and
Rodenticide Act, registrants of termiticides to submit
indoor air monitoring data of dwellings treated with a
tenniticide. The dwellings included in th{0 monitoring
study should be of different construction types: sub-
and intra-slab duct, crawl space, full basement. A treatment
history sh.ould also be available for each of the houses in-
cluded in the study. These data will then be used to determine
if exposure to the dwelling occupant occurs when termiticides
are applied according to current label directions and
application rates.
Concurrent with the requirement for registrants to submit
monitoring data, the Agency is contacting several private
researchers and state regulatory agencies for any monitoring
data that they may have collected as a result of complaints
and/or enforcement efforts.
Vl-4
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BIBLIOGRAPHY
1. Birch, Shelton R. Memo to Lois Rossi regarding
data from Air Force monitoring study of airborne
concentration of termiticides in Air Force housing units.
October 29, 1982.
2. British Crop Protection Council. British Crop Protection
Council 1974 Pesticide Manual: Basic Information
on the Chemicals Used as Active Components of Pesticides.
Edited by H. Martin and C.B^ Worthing. 4th Edition.
London, England.
3. Cahill, W.P. and M.K. Stumphy. Applicator and Inhabitant
Exposure to Chlordane During and After Termiticide
Applications in-California. Velsicol Chemical
Corporation. 1979. Confidential.
4. Colorado State University. National Household Pesticide
Usage Study, 1976-1977. Addendum I: Household
Usage and Storage of Chlordane-Containing Products.
Epidemiologic Pesticide Sjtudies Center,
-------
12. Maddy, K. et al. A Study in Southern California'in
July, 1979 of the Potential Dermal and ZnhalaticTn
Exposure of Applicators and Other Persons Who
Might Later Enter or occupy Areas Treated with
Chlordane Used Against Subterranean Termites
Under Bouses, California Department of Pood and
Agriculture, Sacramento, California. 1979.
13. Merck Index. Ninth Revision. •.
14. Messerschmidt, M. Olav. Letter-to Loil Rossi regarding
EPA Risk/Benefit Analysis of Termiticides.
June 9, 1983.
15. National Academy of Sciences. Committee on Toxicology.
An Assessment of the Health Risks of Seven Pesticides
Used for Termite Control. Washington, D.C. 1982..
T»
16. National Academy of Sciences. Committee on Toxiciology.
Chlorpyrifos Risk Assessment and Inhalation
Exposure Limits. Washington, D.C. 1978.
17. National Academy of Sciences. Subcommittee on Chlordane
in Military Housing of the Committee on Toxicology.
Chlordane in Military Housing prepared for the
United States Air Force/ Washington, D.C. 1979.
18. National Pest Control Association. The Structural Pest,
Control Industry, Description and Impact on the
Nation. NCPA, 1981.
19. Nolan, R.J.; Rick, D.L.; Preshour, N.L. and J.H. Saunders.
Chlorpyrifos: Pharmacokinetics in Human Volunteers.
(In Press)
20. Office of the Surgeon, Headquarters Air Porce Logistics
Command, Wright-Patterson Air Porce Base, Ohio.
Summary and Comparison of Two-hour Baseline Chlordane
Air Sampling Results prom Air Porce Military Family
Housing. 1975.
21. Regional Environmental Health Laboratory, Kelly Air Force Base,
Technical Report: -Chlordane Contamination of
Government Quarters and Personal Property, Webb
Air Force Base, Texas. 1970.
22. Shell Research Limited, London. Assessment of Exposure
Following the Use of Aldrin as a Termiticide in Homes.
December, 1982. Confidential.
23. Shindell, Sidney. Letter to Will Brocker, Velsicol Chemical
Corporation regarding EPA Risk/Benefit Analysis of
Termiticides. June 3, 1983.
VI1-2
-------
24. Telang, S.; Tong, C.r and G.M. Williams. Epigenetic membrane
effects of a possible tumor promoting type on
cultured liver cells by the non-genotoxic organochlorine
pesticide chlordane and heptachlor. Carcinogenesis.
Vol. 3, No. 10, pp. 1175-1178, 1982.
25. Tenniticides in Building Protection. Proceedings of a
Workshop, September 22-23, 1982, Washington, D.C.,
1983. Edited by A. Khasawinah, Velsicol Chemical
Corporation, Chicago, Illinois. *
26. United States Department of the Air Force. Chlordane
Contamination in Wherry Housing, Scott Ai'r Force
Base, Illinois. 1979.
27. United States Department of the Air Force. Office of
the Surgeon, Headquarters Air Force Logistics
Command, Wright-Patterson Air Force Base, Ohio.
Summary and Comparison of Two-Hour Baseline Chlordane
Air Sampling Results From Air Force Military Family
Housing. May 13, 1975.
28. United States Air Force Occupational and Environmental
Health Laboratory, Aerospace Medical Division,
Brooks Air Force Base, Texas. Chlordane in Air
Force Family Housing - A Study of Houses Treated Prior To
Construction. June 1982.
29. United States Department of the Air Force. USAF
Environmental Health Laboratory, Kelly Air Force
Base, Texas. Chlordane Contamination of Government
Quarters and Personal Property, Webb Air Force Base,
Texas. March 12, 1970.
30. United States Department of the Air Force. USAF
Occupational and Environmental Health Laboratory,
Aerospace Medical Division, Brooks Air Force Base,
Texas. Chlordane in Air Force Family Housing:
A Study of Slab-On-Grade Houses, April 1983.
31. United States Environmental Protection Agency. Ambient
Water Quality Criteria for Aldrin/Dieldrin.
Office of water Regulations and Standards, Washington,
D.C. 1980.
32. United States Environmental Protection Agency. Ambient
Water Quality Criteria for Chlordane. Office of
Water Regulations and Standards, Washington, D.C.
1980.
33. United States Environmental Protection Agency. Ambient
Water Quality Criteria for Heptachlor. Office of
Water Regulations and Standards, Washington, D.C.
1980.
VI I-3
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34. United States Environmental Protection Agency. Creosote,
Inorganic Aresenicals, Pentachlorophenol Position
Document 2/3. Office of Pesticides and Toxic
Substances, Washington, D.C. 1981.
35. United States Environmental Protection Agency.
Comparative Benefit Analysis of the Seven Chemicals
Registered for Use Against Subterranean Termites.
Benefits and Field Studies Division, Office
of Pesticide programs, Washington? O.C. 1981.
35o United States Environmental Protection Agency.
Lindane Position Document No. 2/3. Office of
Pesticides and Toxic Substances, Washington, O.C.
1980.
37. United States General Accounting Office. Need for a
Formal Risk/Benefit Review of the Pesticide Chlordane.
Report No. B-199618. 1980.
38. Velsicol Chemical Corporation. Report of Epidemiologic
Study of the Employees of Velsicol Chemical Corporation
Plant, -Memphis, Tennessee. January, r§52 - December,
1979. 1980.
39. World Health Organization, International Agency for
Research on Cancer. IARC Monographs on the Evaluation
of the Carcinogenic Risk of Chemicals to Humans.
Some organochlorine pesticides. Volume 5, 1974.
pp. 25-38; pp. 125-156.
40. World Health Organization, International Agency for
Research on Cancer. IARC Monographs on the Evaluation
of the Carcinogenic Risk of Chemicals to Humans.
Some Halogenated Hydrocarbons. Volume 20, October 1979,
pp. 45-65, pp. 129-154, pp. 195-239, pp. 303-325.
•I2-
41. World Health Organization, International Agency for Research
on Cancer. IARC Monographs on the Evaluation of.Jthe
Carcinogenic Risk of Chemicals to Humans. Chemicals,
Industrial Processes and Industries Associated with
Cancer in Humans. IARC Monographs, Volumes 1 to 29.
IARC Monographs Supplement 4. October, 1982.
42. Wright, C.G. and R.B. Leidy. Termite Control Produces
Low Levels Chlordane and Heptachlor in Treated Houses.
Pest Control Technology, July, 1982, p.44-45,55.
VI I-4
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APPENDIX 1
PHYSICAL.AND CiEMICAL PROPERTIES OF TEFMITICIDES
CHUTRDANE
chemical name:
Cnera. Abstr.
Services Reg. No.:
molecular weight:
color:
odor:
melting point:
boiling point:
solubility:
physical state:
density:
vapor pressure:
viscosity;
stability:
1,2,4,5,6,7,8,8-Octachlcro-4,7-tnBthano-
3a,4,7,7a-tetrahydroindane
57-74-9
409.8
amber
chlorine odor
106-107QC (cis-isoner);
104-105°C (trans-isoner);
decomposes at 1 atm.
Insoluble in vater; soluble in most
organic solvents, including petroleum
hydrocarbons
liquid
d2S 1.59-1.63
0.00001 nm at 25<=C
75-120 centistokes at SSPT
loses chlorine in presence of alkaline
reagents; should~not be femulated with
solvents, carriers, diluents, emulsifiers,
which have alkaline reactions;
-------
HEPTK3LDR
chemical nsne:
Chan. Abstr.
Services Reg. No.
molecular weight:
molecular fonajla:
color:
odor:
melting point:
boiling point:
solubility:
physical stater
density:
vapor pressure r
viscosity:
stability:
1,4,5,6,7,8,8a-Heptachlorc-3a,4,7,
7a-tetrahydrc~4,7-jnsthanoindane
76-44-8
373.5
white (pure); light tan (technical)
canphor-lifre odor
135-145QC at 1-1.5 asa
practically insoluble in water*
soluble in ethanol, xylener carbon
tetrachloride, acetone, and benzene
crystalline solid
1.57-1.59
0.0003 mm at 25°C
not applicable
stable in daylight, air, moisture,
and moderate heat; oxidized biologically
to heptachlor epoxide;
-------
ALDRIN
chemical name:
Chem. Abstr.
Services Reg. No.
molecular weight:
molecular formula:
color:
odor:
melting point:
boiling point:
solubility:
physical state:
density:
vapor pressure:
viscosity:
stability:
1,2,3,4,10,10-Hexachlorc-l,4,4a,5
8,8a-hexahydro-i,4,5,8-dimethanonapthalene
309-00-2
364.9
white (pure); tan to dark brown (technical)
ehefaical°liXe odor
104-104. 5°C
deu.mgjuaes at 1 am.
very soluble in nest organic splventsl
practically insoluble in water;
crystalline solid
1.70 at 20QC
2.31 x 10-5 am Bg at 2QQC
not applicable for solid
stable with alkali and alkaline-
oxidizing agents; not stable with
concentrated mineral acids, acid catalysts,
acid-oxidizing agents, phenols, active metals
-------
DIcIDRIN
chemical nans:
Gieau Abstr.
Services Reg. No.
iBolacular weights
nolecular fonsula:
color:
odor:
melting point:
boiling point:
solubility:
physical state:
density:
vapor pressurei
viscosity:
stability:
1,2,3,4,10,10-Hexachlorc—6,7-epoxy
1,4,4a,5,6,7,8,8a-octahydro-l ,4,5,8
dimethanonaphthalene
60-57-1
380.9
(pure)r light tan (technical)
^>
odorless
176-1770C
at 1 atsu
practically insoluble in water;
slightly soluble in 'petroleum oils;
Moderately soluble in acetone;
soluble in aronatic solvents;
crystalline solid
1.70 at 2QQC
1.78 x 10~7 nan Bg at 20«C
not applicable for solid
stable in alkalis and in acids except
strong mineral acids;
-------
CHLORPYRIFOS
chemical name:
Chen. Abstr.
Services Reg. No.
molecular weight:
molecular formula:
color:
odor:
melting point:
boiling point:
solubility:
physical state:
density:
vapor pressure:
viscosity:
stability:
0,O-Diethyl O-(3,5,6-trichloro-2-
pyridyl) phosphorothioate
2921-88-2
351
white
mild mercaptan odor
42.5-43°C
soluble in most organic solvents
t
crystalline solid
1.87 x 11T5 nn Hg at 25°C
stable under normal storage conditions
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