PESTICIDES USED IN MARYLAND FOR MOSQUITO CONTROL
POTENTIAL ADVERSE EFFECTS
The Maryland Pesticide Network supports using non-toxic means as a first line of defense. In the event of evidence of mosquito-borne disease, we support a least toxic approach to pest control. In light of our support of the public's right-to-know, we have gathered information on pesticides used in Maryland for mosquito control and their potential adverse health effects from various sources including, US EPA, EXTONET (a pesticide information project of Cooperative Extension offices of Cornell University, Oregon State University, the University of Idaho, the University of California at Davis and Michigan State University), Consumer Policy Institute Of Consumers Union, Beyond Pesticides/National Coalition Against the Misuse of Pesticides and the National Coalition for Alternatives to Pesticides. Additional resources - texts/journals/presentations have been footnoted.
PESTICIDES AND CHILDREN
Generally, children are more at risk than adults from pesticide use. In 1993 the National Academy of Sciences (NAS) published a report "Pesticides in the Diets of Infants and Children that documented the risks of pesticides to children. Children are more susceptible for a number of reasons: they are undergoing rapid growth and development; they have different metabolism and excretion of pesticides; and they are more exposed.
Rapid growth and development means that pesticides that are neurotoxic are of particular concern; unfortunately as documented by the NAS, many neurotoxic pesticides have never been evaluated for their ability to affect the development of children's brains. In 1999, the EPA issued a data call in for this type of testing to be conducted on many of the most common insecticides, the so-called organophosphate (OP) and carbamate pesticides. Unfortunately, it will be a number of years before this testing is completed.
Different metabolism means that testing of the pesticide on adult animals may not reflect the exposures that infants and children have. Children are more exposed for three reasons: they eat, drink and breathe more per body weight than adults do; they have much more hand to mouth activity, and they spend more time on floors and lawns. The EPA has not yet completed the job of ensuring that pesticides on the market today are safe for children.
In response to the NAS report, the U.S. Congress enacted the Food Quality Protection Act (FQPA) in 1996 that requires EPA to reassess all food use pesticides to ensure that they are safe for children. The EPA has not completed this work but already has determined that three OP insecticides, azinphos methyl, chlorpyrifos and methyl parathion, were in use at levels that were not safe for children. Under the FQPA, the EPA must consider the cumulative (or additive) risk of all pesticides that act in a similar fashion. Clearly if individual pesticides are in trouble, the cumulative risks will be found to be much too high. This is a process that promises to play out over a number of years.1
PESTICIDES USED FOR MOSQUITO CONTROL IN MARYLAND
Larvicides - used to kill mosquito larvae:
Bacillus thuringiensis (Bt):
Bt is a naturally occurring soil bacterium. While EPA considers Bt to be among the safer pesticides and finds the toxicological database essentially complete, the Agency is still requiring additional data on ecological effects. Bt is completely biodegradable. We do support an expanded use of this larvicide to effectively reduce mosquito populations with the least risk to human health. However, Bt formulations can contain anywhere from 0-99+% 'inert' ingredients (see more on inerts below).
Methoprene:
Methoprene is an insect growth regulator, which mimics an insect growth regulation hormone. It is slightly toxic to birds and slightly to moderately toxic to fish. In 1997, scientists reported a possible link between methoprene and deformed frogs found in Minnesota and eleven other states. There is a growing concern about the effects of methoprene on shellfish such as lobsters. Shellfish and insects rely on similar hormonal clues for molting and methoprene can kill both of these types of animals.
Adulticides - used to eliminate adult mosquitoes:
The two pesticides the state of Maryland may use to combat
West Nile are the synthetic pyrethroids, ANVIL 10 +10 (Sumethrin) and BIOMIST
(Permethrin). These two pesticides are mixed with Piperonyl Butoxide, a synergist
that enhances the killing power of the active ingredients.
If you suspect you may be suffering from exposure to the pesticides used to
combat West Nile Virus, we ask that you go to your nearest emergency room
or contact your physician and ask the health care provider to report the case
to the Department of Health and Mental Hygiene (DHMH) office of Environmental
Health website at http://mdpublichealth.org/oeh/html/hcp.html,
or call 410- 767-8461.
In order to evaluate the impact of pesticides used in the state for public health
concerns, DHMH's data collection is reliant on physicians voluntarily reporting
suspected injuries. We encourage your help in this effort.
The following are symptoms that could be indicative of acute pesticide injury
(from US EPA Recognition and Management of Pesticide Poisonings, Fifth
edition; Chemwatch fact sheets on synthetic pyrethroids and piperonyl butoxide,
National Coalition Against the Misuse of Pesticides ) :
POSSIBLE ACUTE SYMPTOMS OF PESTICIDE POISONING
ANVIL (Sumethrin) and BIOMIST (Permethrin) :
Effects on the nervous system such as itching,
numbing, burning or tingling
Respiratory problems (synthetic pyrethroids
are known to exacerbate respiratory illnesses such as asthma)
Hyper excitability
Irritation of the eyes
Salivation
Tremor
Abnormal facial sensation
Dizziness
Headache
Fatigue
Vomiting
Diarrhea
Irritability to sound and touch
In more severe cases-
pulmonary edema
muscle fasciculations
PIPERONYL BUTOXIDE:
Vomiting
Diarrhea
Intestinal inflammation
Mild nervous system depression
Skin irritation
POSSIBLE LONG TERM HEALTH EFFECTS OF EXPOSURE
ANVIL (Sumethrin) and BIOMIST (Permethrin) , synthetic pyrethroids, are considered
possible endocrine disruptors by the U.S. EPA. The EPA plans to complete
a safety review of synthetic pyrethroids in 2002 to evaluate this class
of pesticides for its effects on children and the endocrine system.
Permethrin, is also classified as a possible carcinogen by the U.S. EPA.
Anvil and Permanone are mixed with the synergist Piperonyl Butoxide (PBO).
PBO is also classified as a possible carcinogen by EPA.
A FEW WORDS ABOUT INERTS
Inert ingredients are chemicals used in pesticide products to make the pesticide more potent or easier to use. Despite their misleading name, inerts are neither chemically, biologically, or toxicologically inert. Often the greatest percentage of chemicals in a pesticide product are inert ingredients - chemicals claimed as trade secrets by manufacturers. Many inerts are hazardous. Of the almost 2600 chemicals that EPA believes are currently used as inert ingredients, over 600 have already been classified as hazardous by state, federal and international agencies. Examples of hazardous and commonly used inerts include crystalline silica (causes cancer and genetic damage), naphthalene (causes anemia and liver damage) and xylene (cause headaches, confusion and fetal death).
Footnotes
1. Testimony of Lynn Goldman, M.D. , pediatrician and former assistant Administrator of EPA's Pesticides, Prevention and Toxic Substances division, before a MD Senate committee, 2000.
2. U.S. EPA. Office of Pesticide Programs, Health Effects Division. 1997. Tox oneliners: Permethrin. Washington, DC, June 24.
3. Spencer, F. and Z. Berhane. 1982. Uterine and fetal characteristics in rats following a post-implantational exposure to permethrin. Bull. Environ. Contam. Toxicol. 29: 84-88.
4. Cecil's Textbook of Medicine, 2000, V.1; Life Science, 1994, V.54(18); Toxicology, Nov. 22, 1992, V.76(10); Journal of Environmental Science Health, 981, V16(5PTB); Journal of Applied Toxicology, Nov-Dec 1996, V.16(6); The testimony of Richard Bernstein, M.D., pulmonary specialist before a MD Senate committee, 2000.