APPENDIX    II-V: Comprehensive Mosquito-Borne Disease Surveillance and Control Plan


January 7, 2001

Douglas G. Aspros, D.V.M.


Westchester County Board of Health

145 Huguenot Street


New Rochelle, NY 10801


            Re: Comprehensive Mosquito-Borne Disease Surveillance and Control Plan

Dear Dr. Aspros:


            Riverkeeper, as a signatory to the 1997 New York City Watershed Memorandum

of Agreement, routinely comments and participates in thc State Environmental Quality

Review Act (SEQRA) process for development proposal~ and policy decisions that may

impact the New York City drinking water supply watershed. In keeping with this role,

Riverkeeper offers the following comments on Westchester County's Comprehensive

Mosquito-Borne Disease Surveil1ance and Control Plan Draft Generic Environmental

Impact Statement (DGEIS).


Project Purpose and Need


While Riverkeeper believes that the education and surveillance components of the

Comprehensive Plan are essential to protecting the public's health and welfare, we are in

no way convinced that the threat posed by the West Nile virus justifies the risk that

mosquito control via larvicides and adulticides poses to the health and well-being of both

the citizens and the environment of Westchester County. According to the DGEIS, a

1999 serosurvey estimated the incidence of West Nile virus infection in New York City

to be 2.6%.(1)   This means that out of the City's population of approximately 8 million,

208,000 were infected with the West Nile virus. However, only 35 clinical cases were

reported nationwide and only 7 deaths of "e1derly citizens" resulted. Therefore the risk

of falling ill with West Nile virus was only 0.00017% and the risk of death was only

0.000035%, which is less than I in a minion of the people infected.(2)  In addition, death

was limited to the sensitive elderly members of the population.


            Despite only 35 cases of West Nile virus out of a (U.S.) population of at least 8

million (3), Westchester County predicts 21, or 60% of the number of reported human cases in the entire United States, hospitalized cases a year in the No Action Scenario (4). This would require Westchester County to have a population base of 4.8 million when it is actually 923,459.(5)  The County also assumes a death rate of 1 per year when the actual rate is only 0.15 deaths per year with a population of 923,459.


            Furthermore, the DGEIS compares the public health impacts of the projected disease outbreaks with the health impacts of insecticide application under the Comprehensive 'Plan using tile unrealistic assumption of zero incidence or disease under the Comprehensive Plan.  In fact, there is no positive correlation between spraying of

adulticides and the incidence of West Nile virus in humans.  In 2001 the New York City

Department of Health applied adulticides in Staten Island and parts of Queens, but not in

the Bronx. Brooklyn or Manhattan.(6)  In that same year. two people in Staten Island, two people in Queens, two people in Brooklyn, one person in Manhattan. and no one in the Bronx tested positive for Wets Nile virus:  No deaths were attributed to the virus.


            These numbers demonstrate that the risk West Nile virus poses to the average citizen is insignificant- This insignificant risk cannot justify the multitude of health and safety risks posed by the application of 1arvicides and adulticides.  The pesticides that the

County proposes to use present a host of known human and environmental health threats, as well as an undocumented number of additional, as of yet unknown, threats.  "The primary purpose of the- proposed Westchester County Comprehensive Mosquito-Borne Disease Surveillance and Control Plan is to protect the public from outbreaks of

mosquito-borne diseases [principally West Nile virus] that pose a threat to public

health.” (8)  However, the County's own risk assessment of the proposed pesticides clearly demonstrates that the application of said chemicals poses a greater threat to public health than the mosquito-borne West Nile virus.


            EPA's acceptable target risk range for carcinogenic pesticides is one in a million (9), which is greater than the risk of death from the West Nile virus. Some of the proposed adulticides attend cancer risks greater than one in a million (l0) with risks running as high as  8 in a million for exposure to permethrin.(11)  The average annual number of deaths from cancer in Westchester County is 1,982.(12)  The projected average annual number of deaths from West Nile virus is less than one, yet the County is willing to spray carcinogenic pesticides all over the County in an effort to prevent that fraction of a death.  In addition, as implied supra, there is no empirical evidence that the use of adulticides reduces the number of human cases of West Nile virus. Clearly, it is counterintuitive to envelop the entire County in a mist of pesticides that present a greater human health risk than the disease the pesticides are intended to eradicate.




            The DGEIS is deficient because it fails to set forth any meaningful parameters for

what types of events would trigger the use of adulticides. The DGEIS proposes that the

adulticiding component of the plan would be triggered in the event of an "imminent

threat to public health"(13), but does not set forth any guidance criteria as to what type of

events would constitute an imminent threat to public health. Would an imminent threat

be a single confirmed case of West Nile virus in Westchester County, one death in the

United States, or ten non-fatal cases in New York City?  In order to assess the benefits

and risks of adulticiding in Westchester County, the public requires a more definite and

accurate measure of what type of health threat will trigger such adulticiding..

Assuming the adulticiding component of the plan is triggered, the DGEIS sets

forth neither the type and amount of adulticide that would be used, nor the method of

application.. Pesticide impacts are type-specific and may vary with the application

method.  In order to make informed comments and decisions, the County must make the

public fully aware of its proposed actions. The DGEIS should provide a ranking system

that sets forth the County's preferred adulticides and application methods for particular

areas of the County.


            Migratory birds, especially American crows (Corvus brachyrhynchos), are known

vectors of West Nile virus, and the mosquito species that infect humans with the virus

acquire it from birds.14 The United States Geological Survey (USGS) is currently

working with the United States Department of Agriculture (USDA) to collect blood

samples from crows and other bird species for virus detection along the Atlantic coast.

The research focuses on the; collection of information and samples to help determine the

Extent of wildlife species involved, the distribution of the virus in bird populations, and

whether the range of the virus is expanding beyond the currently reported regions.(15) 

Rather than propose widespread blanket application of pesticides, Westchester County

shou1d avail itself of information gathered by USGS and USDA in the avian surveillance

program to identify focus areas in Westchester County and develop a phased response

protocol to limit or prevent human contact with the virus.


Larvicide and Adulticide Composition


            The DGEIS fails to adequately discuss the health hazards associated with both the

active and inert ingredients of the proposed larvicides and adu1ticides. The Material

Safety Data Sheets (MSDS) available for these products cite health hazards of active



Malathion: Acute and chronic health hazards include: excessive

sweating, headache, weakness, giddiness, nausea, vomiting stomach

pains, blurred vision, blurred speech, diarrhea, and cholinesterase



Naled: Acute and chronic health hazards include irreversible eye

damage; b1indness; redness, swelling and pain of the skin; irreversible

tissue damage; toxicity to internal organs if absorbed through skin;

respiratory depression; cardiac arrest; nausea; vomiting; and diarrhea.

Na1ed is probably carcinogenic to humans based on studies in animals.

and symptoms of overexposure inc1ude: excessive sweating, nasal

discharge, diarrhea, vomiting, convulsions, aspiration into lungs,

unconsciousness. and death.


Sumithrin: High concentrations may cause headaches, dizziness, be

anesthetic. and have other central nervous system effects.


Permethrin: Doses of this product administered to 1ab animals have

produced central nervous system effects with symptoms that include

hypersensitivity to touch and sound, tremors, .and convulsions, rattling

and irregular breathing, and ataxia.


Temephos:  Acute health hazards include eye irritation, respiratory

irritation, chemical pneumonitis, and chronic health hazards are



Piperonyl Butoxide: May be fatal if inhaled, swallowed, or absorbed

through the skin.  Most disturbingly, the MSDS states that the chemical,

physical, and toxicological properties have not been thoroughly



            These human health risks alone, without any consideration of the impacts these

pesticides have on the natural environment, clearly outweigh the risk that West Nile

Virus poses to the popu1ation of Westchester County.


Inert Ingredients


The DGEIS also fai1s to adequately assess the health and environmental impacts

of the inert ingredients contained in the pesticides because their composition is

unknown (16)  Inert ingredients may compose up to 90% or more of a pesticide product.

This means that the County is willing to spray a product, the composition of which over

90% is unknown, over our yards, parks, houses, playgrounds, swimming pools, and

schools. School children, infants, asthmatics, the elderly, and pregnant women will be

exposed. eventually these pesticides will contaminate our waterways via stormwater

runoff.  This high level of unknown risk is simply unacceptable given the so-called risks

of West Nile virus.

Many of these “inert" ingredients are petroleum distillates and share some of the

same chemical constituents as gasoline.  The public would never tolerate the spraying of

gasoline over our communities, allowing that form of petroleum to run off into our water

supplies. Yet when other petroleum distillates are mixed with highly hazardous active

ingredients and dispersed over our communities, the County maintains that it is an action

to protect public health.  Petroleum products in our surface water supply can result in a

host of environmental problems including fish kills and contamination of groundwater

and drinking water supplies.


            The simple fact remains that known health risks associated with the use of

larvicides and adulticidcs outweigh the health risks posed by West Nile virus. The

combined risk of the known and unknown hazards of pesticides dramatically overwhelms

the minute risk to the general population associated with West Nile virus.


Aquatic Life


            The adulticides the county proposes to use are widely toxic to aquatic life.

Figure 3.D-25 demonstrates that the proposed adulticides are highly toxic to a wide

variety of aquatic life in a variety of aquatic habitats. The DGEIS lacks sufficient

information to ensure that aquatic environments will not be adversely affected by

adulticide use.  The DGEIS does not set forth a concrete p1an or a list of specific

precautions that will be implemented to prevent, or at the very least mitigate to the

maximum extent practicable. the introduction of adulticides into aquatic environments.


            Although pesticide labels may prohibit use on or within a certain distance from a

water body, such prohibitions are simply inadequate to protect the sensitive waterways of

Westchester County.  Five of the Croton watershed's drinking water supply reservoirs are

located in Westchester County. More importantly, the Kensico Reservoir, which is the

terminal reservoir for the entire West-or-Hudson Catskill and Delaware watersheds, and

the New Croton and Hil1view Reservoirs, which are the terminal reservoirs for the entire

East-of-Hudson Croton watershed, are located in Westchester County. All East-of-

Hudson reservoirs are already stressed by the attendant impacts of sprawl to water

quality.  Additional impacts to watershed macroinvertebrate communities by the

widespread application of pesticides will only result in the further degradation of water

quality.  These Croton Watershed reservoirs are fed by streams and tributaries that may

not be visible to sprayers at night. How will these waterways be protected, or will they

be protected at all?  These are issues that must be addressed and go unanswered in the DGEIS.


            Furthermore, the County presumes that the use of the proposed larvicides will not

impact aquatic life because discharged concentrations in catch basins "would not be

greater than what would result from a single application of the regular formulation, which

has been found to have minimal effects to [sic] non-target organisms [and] impacts to

non-target organisms would be further reduced by dilution….”(17)  The cumulative

concentration of larvicides applied to a subwatershed and transported in runoff will

collect in the catch basins and will be discharged in a concentrated form to receiving

waters. The argument that dilution is the solution to pollution has long since been



            Additionally, parts of the DGEIS represent an alarming compilation of faulty and

unfounded assumptions. The County assumes the sequestration of freshwater in lenses in

saltwater; (18) the universal dilution of contaminated discharges to estuaries;(19) the

burrowing of benthic organisms to escape exposure;(20) and the assumption that the

bonding of insecticides to suspended sediment and settling results in no pollution in the

water column.(21)  These broad generalizations are not quantified anywhere in the DGEIS and therefore fail to support the County's conclusion that "adverse impacts on natural resources are not expected from the application of larvicides.(22)


Aquatic Receptors in Wetlands Exposed to Runoff


The DGEIS suggests that approximately 0.2% of applied permethrin is contained in

runoff during any given rain event.(23)  If this is correct, then the annual rate of 1 %

assumes only 5 rain events per season of app1ication.(24)  This assumption appears to be

arbitrary and conservative and the County fails to cite any authoritative source to support



            The DGEIS reports that stormwater discharge elevates levels of malathion in

streams(25) and that benthic communities exposed to malathion in Florida recovered in 42 days.(26)  While this may be true in a subtropical environment such as Florida, there is no evidence that benthic communities in the northeastern United States would respond in the same manner.  In addition the DGEIS fails to report whether impacted fish populations recovered at all.(27)


            In conclusion, the DGEIS is insufficient and uses faulty assumptions to

exaggerate the risk of West Nile and downplay the hazards of pesticides. The

insignificant risk posed by West Nile virus in no way justifies the magnitude of human

health and ecological risks associated with the widespread dissemination of toxic

pestcides into the environment. Thank you for the opportunity to comment on this




Danielle Abate, Project Analyst

Jeffrey Odefey, Project Attorney


1.  See Comprehensive Mosquito-Borne Disease Surveillance and Control Plan Draft Generic Environmental Impact Statement, November 2001 (hereinafter DGEIS) at S-8-

2.  See id at S-3.

3.  See id. at S.9.

4.  See id. at S-26.

5.  See id. at 5-26.

6.  See New York City Dept. of Health West Nile Virus 2001 Spray Schedule,  2001.

7.  See New York City West Nile Virus 2001 Positive Results Summary,   2001.

8.  DGElS. at S-23.

9.  See id. at S-37.

10.  See id. at S-41.

11.  See id. at S-43.

12.  New York State Dcpt. Of Health, New York State Cancer Registry Canter Incidence and Mortality by County and Gender, 1994-1998, .

13.  DGEIS at S-10.

14.  United Sates Geological Survey Fact Sheet. . 2001.

15.  Id.

16.  See DGEIS at S-66.

17.  ld. at 53.

18.  Id. at 65.

19.  Id.

20.  Id. at 64.

21.  1d. at 65.

22.  Id. at 55.

23.  See DGElS at 63

24.  See Id.

25.  See id. at 64.

26.  See id.

27.  See id.


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