Medical studies indicate health hazards from pyrethroid pesticides

 


            

Subject:  Medical studies indicate health hazards from pyrethroid pesticides----
Date:     Mon, 18 Sep 2000 13:40:58 -0400
From:        Stephen Tvedten <steve@getipm.com>
Organization:     Get Set Inc. (www.getipm.com)

To:     Paul Helliker <phelliker@cdpr.ca.gov>
          Director, State of California, Department of Pesticide Regulation 

Dear Mr. Helliker, I thought you might like to read an article entitled: Medical studies indicating health hazards from pyrethroid pesticides.

Sumithrin (Anvil), resmethrin (Scourge) and permethrin (often used in household bug sprays) each belong to a class of pesticides known as pyrethroids. Sumithrin and resmethrin were not among the pyrethroids specifically studied in all medical studies reported on this page, but these pesticides are closely related to each other.

Links between pyrethroids and breast cancer

The link between sumithrin and other pyrethroids and breast cancer is not proven ­ much more research is needed in this area. But several studies indicate pyrethroids disrupt the endocrine system by mimicking the effects of the female hormone estrogen. This in turn can cause breast cancer in women and lowered sperm counts in men. When estrogen levels are elevated, old cells are not removed from the body and cell proliferation occurs, whether benign or malignant. Mount Sinai School of Medicine: This study examined four pyrethroid pesticides, including sumithrin. It concludes ³Overall, our studies imply that each pyrethroid compound is unique in its ability to influence several cellular pathways. These findings suggest that pyrethroids should be considered to be hormone disruptors, and their potential to affect endocrine function in humans and wildlife should be investigated.² [Environmental Health Perspectives, Vol. 107, No. 3, March 1999, pages 173-177.] The Roger Williams General Hospital, Brown University: This study on pyrethroids concludes ³Chronic exposure of humans or animals to pesticides containing these compounds may result in disturbances in endocrine effects.² [Journal of Steroid Biochemistry, March 1990; 35(3-4):409-14.] Cambridge University: A report issued in June 2000 by the Royal Society in England and written by a group from Cambridge University called for international cooperation to deal with the dangers posed by endocrine-disrupting chemicals, including pyrethroids, and recommends reducing human exposure to these chemicals.

Synergistic effects on endocrine disruptions

Tulane University: This study, conducted by six scientists at three Tulane medical institutions, suggests that combinations of chemicals could have much greater effect that the individual chemicals would on their own, even when an individual chemical has relatively low potential for endocrine disruption by itself. The study found ³The synergistic interaction of chemical mixtures with the estrogen receptor may have profound environmental implications. These results may represent a previously uncharacterized level of regulation of estrogen-associated responses.² [³Synergistic Activation of Estrogen Receptor with Combinations of Environmental Chemicals,² Science Magazine.]

Links between pyrethroids and childhood brain cancers

A study of pesticides and childhood brain cancers has revealed a strong relationship between brain cancers and compounds used to kill fleas and ticks, according to a report published in Environmental Health Perspectives. The study concludes ³The specific chemicals associated with children's brain cancers were pyrethrins and pyrethroids (which are synthetic pyrethrins, such as permethrin, tetramethrin, allethrin, resmethrin and fenvalerate) and chlorpyrifos (trade name: Dursban).² [Janice M. Pogoda and Susan Preston-Martin, "Household Pesticide sand Risk of Pediatric Brain Tumors," Environmental Health Perspectives, Vol. 105, No. 11 (November 1997), pages. 1214-1220.] The EPA, in June 2000, halted sales of Dursban.

Links between pyrethroids and neurological damage

Several studies have indicated neurological damage resulting from exposure to pyrethroids, and some of the damages have been found to be long term. Ludwig Maximilians University: This study, conducted by the Physiological Institute at Ludwig Maximilians University in Munich, Germany, found that although ³a majority of complaints following an acute pyrethroid intoxication disappeared after the end of exposure,² several effects were still seen in patients after more than two years. Among these long-term symptoms were ³(1) cerebro-organic disorders (reduced intellectual performance with 20%-30% reduction of endurance during mental work, personality disorder), visual disturbances, dysacousia, tinnitus; (2) sensomotor-polyneuropathy, most frequently in the lower legs; (3) vegetative nervous disorders,² including increased heat-sensitivity and reduced exercise tolerance due to circulatory disorder. The study concludes ³Many of these patients exhibit pathological autoimmune diagnostical findings and developed autoimmune diseases.² [Toxicology Letters 1999 June 30;107(1-3):161-76.] Uppsala University: This study, conducted by the Department of Environmental Toxicology at Uppsala University in Sweden studied mice, not humans, but found that ³low-dose exposure² to pyrethroids ³resulted in ³irreversible changes in adult brain function in the mouse² when exposed during the growth period. This occurred at levels of exposure less than what was found to affect adult mice. The study also found ³neonatal exposure to a low dose of a neurotoxic agent can lead to an increased susceptibility in adults to an agent having a similar neurotoxic action, resulting in additional behavioral disturbances and learning disabilities.² [Neurotoxicology 1997;18(3):719-26.] Northwestern University Medical School: A series of investigations conducted at Northwestern¹s Department of Molecular Pharmacology and Biological Chemistry in Chicago, has found neurological damage from pyrethroids. One study, conducted by international expert Toshio Narahashi, finds nervous-system damage from pyrethroids to be comparable to DDT. This study found that ³Detailed voltage clamp and patch clamp analyses have revealed that pyrethroids and DDT modify the sodium channel to remain open for an extended period of time.² The result of this damage is ³potent effects on the nervous system.² [³Nerve membrane ion channels as the target site of environmental toxicants,² Environmental Health Perspectives,1987 April;71:25-9.]. A separate study found that pyrethroids cause ³membrane depolarization, repetitive discharges and synaptic disturbances leading to hyperexcitatory symptoms of poisoning in animals.² This study found that only 1% [Pharmacol Toxicol 1996 July;79(1):1-14.]

Links between pyrethroids and thyroid damage

A study conducted by four scientists on a variety of pesticides found a connection to thyroid damage, although this study was conducted on rats and not on humans. The study concludes ³exposure to organochlorine, organophosphorus, and pyrethroid insecticides for a relatively short time can suppress thyroid secretory activity in young adult rats.² The study also said a decrease in body weight seen ³suggests that pyrethroid insecticides can inhibit growth rate.² [Journal of Applied Toxicology, Vol. 16, No. 5, pages 397-400, 26 references, 1996.]

No Spray Coalition Inc.- Hotline (718) 670-711   €   www.nospray.org   €   P.O. Box 334, Peck Slip Station, New York, NY 10272-0334.

Well Mr. Helliker, During the last few years we have seen most of your "registered" cyclodiene chlorinated hydrocarbons, carbamates, and organophosphate POISONS lose their "registrations" and/or have "voluntarily" changed their labels so that these volatile POISONS can no longer be legally applied inside.  Now we have basically only your "registered' pyrethroids left - and the above data shows their inherent dangers.  Because these toxins are basically the only "registered" sprays left, it is obvious the use of pyrethroids and human hazards from exposure to these POISONS will continue to increase and not be reduced!  When will it be "legal" (in your opinion) to use safe and far more effective, unregistered alternatives to actually control pest problems in California?

Respectfully,  Stephen L. Tvedten

(Note:  Does knowing that these the types of pesticides are in lice treatment products and are sprayed over New York and several other states make you feel any better?)

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