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Exposures to Pesticides May Threaten Developing Embryos
(Beyond Pesticides, May 18, 2004) Low-dose
exposures to agricultural and lawn care pesticides may cause injury
to developing embryos before a pregnancy is even noticed, according
to a study conducted by researchers at Marshfield Clinic Research Foundation
(MCRF), Marshfield, Wis., and being published in the May 2004 issue
of Environmental Health Perspectives, the journal of the National Institute
of Environmental Health Sciences, National Institutes of Health.
"In research conducted with mouse embryos, injury was observed
during laboratory studies with a variety of agrochemicals and lawn care
products, such as weed and insect killers and fertilizers, at concentrations
previously assumed to be without adverse health consequences for humans,"
said Anne Greenlee, Ph.D., lead author of the article.
Types of injury observed included slowed embryonic development and reductions
in the number of cells comprising the embryo, both of which may contribute
to implantation failures and lengthening in time needed to achieve pregnancy.
Since it is impossible to define precisely the amount of chemical(s)
dangerous to an individual's reproductive health, a cautious approach
seems best, Greenlee said.
Greenlee, a scientist in Marshfield Clinic Research Foundation's National
Farm Medicine Center (NFMC), said her lab conducted the study because
little is known about residential use of pesticides and their possible
effects on embryonic development in the first few days of pregnancy.
Her study used mouse embryos to model possible human effects as embryos
of different animal species react similarly at this early stage of development.
Greenlee stressed the importance of additional work needed to validate
these findings for purposes of human risk assessment and to determine
relevance of lab results to pregnancy outcomes.
In this study, researchers examined 13 agrochemicals and lawn care herbicides
(weed killers) for their effects on embryo development during the preimplantation
period. The preimplantation period corresponds to the first to seventh
day of pregnancy, when an embryo is rapidly dividing and before implantation
occurs in the mother.
The study, funded by the Wisconsin Department of Agriculture, Trade
and Consumer Protection (DATCP) and MCRF disease-specific research funds,
examined active ingredients in commercial pesticide formulations. Agricultural
chemicals studied are typical of those used in the upper Midwest. Lawn
pesticides studied are typical of those used throughout the United States.
Active ingredients tested included six herbicides (atrazine, dicamba,
metolachlor, 2,4-D, pendimethalin, MCPP); three insecticides (chlorpyrifos,
terbufos, permethrin); two fungicides (chlorothalonil, mancozeb); one
drying agent (diquat) and one fertilizer (ammonium nitrate).
Greenlee's manuscript, "Low-dose Agrochemicals and Lawn Care Pesticides
Induce Developmental Toxicity in Murine Preimplantation Embryos,"
is published online at http://ehp.niehs.nih.gov/docs/2004/6774/abstract.html.
Additional authors are Tammy Ellis, NFMC; and MCRF Biostatistician Dick
Research published by Greenlee in the July 2003 issue of the journal
Epidemiology showed that women who mix and apply pesticides or apply
fungicides in the two-year period before trying to conceive significantly
increase their chances of infertility. In that study, it was shown that
infertile women were 27 times more likely to have mixed and applied
pesticides than women who had become pregnant.
The Marshfield Clinic system consists of 40 patient care and research
and education facilities in Northern, Central, Eastern and Western Wisconsin,
making it one of the largest comprehensive medical systems in the United
TAKE ACTION: Take a precautionary approach
to avoid low-dose exposures to pesticides. Exposure to lawn care chemicals
can be avoided by creating a healthy, pest-resistant lawn. Find out
Get rid of other pests without hazardous pesticides by going to Beyond