ALACHLOR AND ATRAZINE IN GROUNDWATER
WHAT ARE ALACHLOR AND ATRAZINE?
Alachlor and atrazine are used as selective
herbicides for controlling grasses and broadleaf weeds. They are usually
applied to the soil surface either before or just after a crop has emerged.
Alachlor is used mainly on corn and soybean fields, but also can be used in
commercial nurseries. Atrazine is used mainly on corn fields.
Alachlor is usually sold under the trade name
"Lasso," but other names include "Chimiclor,"
"Alanox," and "Pilarzo." Atrazine is sold under the trade
names "AAtrex" and "Azinotox 500." Alachlor and atrazine
also are components of other herbicide mixtures.
Products containing alachlor and atrazine are
classified as "restricted use" herbicides. Restricted use herbicides
must be used by persons who are certified applicators or under the supervision
of a certified applicator. One reason the use of alachlor and atrazine has been
restricted is because of concerns about groundwater contamination.
HOW DO ALACHLOR AND ATRAZINE GET INTO THE
Alachlor and atrazine mainly enter the
environment through application to farm fields. These herbicides also can get
into the environment if they are improperly stored or mixed before application.
Groundwater contamination may occur when alachlor or atrazine moves from an
application or spill on soil into a shallow aquifer. Improperly constructed
wells have a high risk of contamination.
HOW MIGHT I BE EXPOSED TO ALACHLOR AND
Exposure to alachlor and atrazine in
groundwater occurs mainly by drinking contaminated water. You also may be
exposed to small amounts through your skin while bathing or showering. Alachlor
and atrazine do not evaporate well, so you are not likely to breathe vapors of
HOW CAN ALACHLOR AND ATRAZINE AFFECT MY
Most studies of health effects due to exposure
to alachlor and atrazine have been done with animals. Alachlor can cause skin
or eye irritation. Drinking water that contains alachlor for long periods may
damage the liver, kidneys, eyes, and spleen. There is no evidence that this
herbicide causes cancer in humans, but it is classified as a probable human
carcinogen because it has been linked to tumors in mice and rats.
Atrazine also can cause skin and eye
irritation, as well as skin allergies. Drinking water that contains atrazine
for long periods may damage the heart and liver. Short-term exposure to low
levels of this herbicide are unlikely to cause health problems. While there is
no evidence that atrazine causes cancer in humans, it is classified as a
possible human carcinogen because it has been linked to tumors in rats.
ARE THERE ANY GUIDELINES TO PROTECT HUMAN
The U.S. Environmental Protection Agency has
set a maximum contaminant level (MCL) for drinking water of 2 micrograms per
liter for alachlor and 3 micrograms per liter for atrazine. A microgram per
liter is comparable to one drop of herbicide in 16,000 gallons of water. MCLs
are meant to protect public health and apply to all public drinking water
HOW CAN I REDUCE OR ELIMINATE MY EXPOSURE TO
ALACHLOR AND ATRAZINE IN GROUNDWATER?
Several management practices can reduce or
prevent the contamination of groundwater. These include proper well
construction and appropriate herbicide handling practices. If your well is
contaminated, using quality bottled water for drinking purposes will greatly
reduce your exposure to these herbicides. Alachlor and atrazine in drinking
water may be reduced or eliminated by filters containing granular activated
carbon. However, these filter systems must be serviced regularly to work
WHERE CAN I GET MORE INFORMATION?
Illinois Department of Public Health
Division of Environmental Health
525 W. Jefferson St.
Springfield, IL 62761
TTY (hearing impaired use only) 800-547-0466
This fact sheet was supported in part by
funds from the Comprehensive Environmental Response, Compensation, and
Liability Act trust fund through a cooperative agreement with the Agency for
Toxic Substances and Disease Registry, Public Health Service, U.S. Department
of Health and Human Services.