RESEARCH TRIANGLE PARK, North Carolina, December
5, 2003 (ENS): Exposure to the pesticide endosulfan
damages developing male reproductive organs and hormones,
according to the first human study to assess the effects
of this chemical on male sexuality. Boys in India who
were exposed to endosulfan showed delayed sexual maturity
compared with similar children who were not exposed,
the new research indicates.
Endosulfan also appears to interfere with sex hormone
synthesis, according the study of males aged 10 to 19
years in a cashew plantation community in northern Kerala
The lead author on the study was Dr. Habibullah Saiyed
of the National Institute of Occupational Health, which
is associated with the Indian Council of Medical Research.
Researchers evaluated and compared 117 boys in a village
where endosulfan has been aerially sprayed for more
than 20 years and 90 comparable boys from a nearby village
with no such exposure history.
For each group, the researchers performed physical
examinations and recorded clinical history, sexual maturity
rating, and blood levels of various hormones. The study
group showed a higher prevalence of congenital abnormalities
related to testicular descent than the control group,
but it was not statistically significant due to the
small sample size.
"Our study results suggest that endosulfan exposure
may delay sexual maturity and interfere with hormone
synthesis in male children," Dr. Saiyed and his
"The practice of aerial spraying of endosulfan
was discontinued in December 2000. Serum endosulfan
residue levels were significantly higher in the study
population than in the control group even 10 months
after the last aerial spray," they write.
U.S. federal public health agencies are taking note
of this research. The study is contained in the December
issue of the peer reviewed journal "Environmental
Health Perspectives" (EHP) published by the National
Institute of Environmental Health Sciences, part of
the U.S. Department of Health and Human Services.
Although endosulfan is no longer made in the United
States, the chlorinated insecticide is currently registered
to control insects and mites on 60 U.S. crops, including
squash, pecans, and strawberries. An estimated 1.4 to
2.2 million pounds are used in the United States annually.
Commenting on the study, Dr. Jim Burkhart, science
editor for EHP, says, "This is the first human
study to ever measure the effects of endosulfan on the
male reproductive system."
"Decades of spraying this pesticide, and only
this pesticide, on the village provided a unique opportunity
to analyze its impact," Burkhart said. "Although
the sample size is somewhat limited, the results are
Classified as an organochlorine, in the same family
of pesticide as DDT and dieldrin, endosulfan and its
breakdown products are persistent in the environment
with an estimated half-life of nine months to six years.
It is one of the most commonly detected pesticides in
U.S. water, found in 38 states.
Exposure to endosulfan happens mostly from eating contaminated
food, but may also occur from skin contact, breathing
contaminated air, or drinking contaminated water, according
to the federal agency that evaluates the human health
effects of exposure to hazardous substances in the United
States, the Agency for Toxic Substances and Disease
"We do not know if endosulfan can affect the ability
of people to have children or if it causes birth defects,"
the ASTDR says. "Large amounts of endosulfan damaged
the testes of animals, but it is not known if this damaged
their ability to reproduce. Some birth defects have
been seen in the offspring of animals ingesting endosulfan
In addition to its effects on the sexual development
of males, endosulfan affects the central nervous system
and prevents it from working properly. Hyperactivity,
nausea, dizziness, headache, or convulsions have been
observed in adults exposed to high doses, according
to the ASTDR, which warns that severe poisoning may
be fatal. Scientists do not know whether or not endosulfan
Studies of the effects of endosulfan on animals suggest
that long term exposure to the pesticide can also damage
the kidneys, testes, and liver and may possibly affect
the body's ability to fight infection. The ASTDR says
it is not known if these effects also occur in humans.
Endosulfan enters the air, water, and soil during its
manufacture and use. When sprayed on crops, the spray
may travel long distances before it lands on crops,
soil, or water.
Endosulfan on crops usually breaks down in a few weeks,
according to the ASTDR, but the pesticide sticks to
soil particles and may take years to completely break
Endosulfan does not dissolve easily in water. Endosulfan
in surface water is attached to soil particles floating
in water or attached to soil at the bottom. The pesticide
can build up in the bodies of animals that live in endosulfan
Endosulfan has been banned in several countries, including
Cambodia, Colombia, Germany, Sweden, Norway, Indonesia,
and others. Its use is severely restricted in at least
20 other countries.
In India, endosulfan is widely used on many crops.
Alarm over the health and environmental effects of the
pesticide intensified in 2002 when a report on the pesticide
appeared in “Down to Earth” a monthly journal
from Centre for Science and Environment (CSE), New Delhi.
The report linked the spraying of endosulfan with the
high incidence of deformities and diseases in the Kerala
cashew plantation village of Padre in the Kasaragod
The Plantation Corporation of Kerela had been spraying
endosulfan since the mid-1970s on its cashew plantations.
The CSE analysis showed high levels of residue of pesticide
in the samples. As soon as the news appeared in the
national media, the National Human Rights Commission
asked the government agencies, including the Indian
Council of Medical Research, to act.
Both the national and the Kerala state governments banned
the aerial spraying of endosulfan, and as of December
2000 no more spraying occurred, but the pesticide still
remains in soil and water.
But the agricultural and pesticide industries fought
the rulings. The industry commissioned the Fredrick
Institute of Plant Protection and Toxicology to conduct
a study, which found that endosulfan was not harmful.
Activists opposing use of the pesticide were threatened
with legal action.
India is the largest manufacturer of endosulfan in
the world. Three companies produce endosulfan in India
- the largest is Excel Industries, the others are Hindustan
Insecticide Limited and EID Parry.
Remediation of soil and water contaminated with endosulfan
may soon be possible. Last February, scientists at the
University of California, Riverside (UCR) announced
that they have isolated microorganisms capable of degrading
Bioremediation of contaminated sites and water bodies
by using these microbial strains will provide an environment
free of endosulfan toxicity, the researchers indicate
in their paper, published in the "Journal of Environmental
"We have been successful in isolating strains
that can use endosulfan as a carbon and energy source,"
said William Frankenberger, director of the UCR Center
for Technology Development and professor of soil science
and soil microbiologist at the university.
The results of the study suggest that these microbial
strains are a valuable source of enzymes that degrade
endosulfan. They may be used for the detoxification
of endosulfan in contaminated soils, wastedumps and
water bodies, as well as agricultural dealership sites,
waste water from recycling plants and unused or expired
stockpiles of endosulfan.
Copyright Environment News Service (ENS) 2003. All