This is a fact sheet about a chemical that may be found in some public or
private drinking water supplies. It may cause health problems if found
in amounts greater than the health standard set by the United States
Environmental Protection Agency (EPA).
What is Dalapon and how is it used?
Dalapon is a colorless liquid with an acrid odor sold as sodium or
magnesium salt. Dalapon is a herbicide used to control grasses in a wide
variety of crops, including fruit trees, beans, coffee, corn, cotton and
peas. It is also registered for use in a number of non-crop applications
such as lawns, drainage ditches, along railroad tracks, and in
The list of trade names given below may help you find out whether you
are using this chemical at home or work.
Trade Names and Synonyms:
Why is Dalapon being regulated?
In 1974, Congress passed the Safe Drinking Water Act. This law requires
EPA to determine safe levels of chemicals in drinking water which do or
may cause health problems. These non-enforceable levels, based solely on
possible health risks and exposure, are called Maximum Contaminant Level
The MCLG for dalapon has been set at 0.2 parts per million (ppm)
because EPA believes this level of protection would not cause any of the
potential health problems described below.
Based on this MCLG, EPA has set an enforceable standard called a
Maximum Contaminant Level (MCL). MCLs are set as close to the MCLGs as
possible, considering the ability of public water systems to detect and
remove contaminants using suitable treatment technologies.
The MCL has also been set at 0.2 ppm because EPA believes, given
present technology and resources, this is the lowest level to which
water systems can reasonably be required to remove this contaminant
should it occur in drinking water.
These drinking water standards and the regulations for ensuring
these standards are met, are called National Primary Drinking Water
Regulations. All public water supplies must abide by these regulations.
What are the health effects?
Short-term: Dalapon is not known to cause any health problems when people
are exposed to it at levels above the MCL for relatively short periods
Long-term: Dalapon has the potential to cause the following
effects from a lifetime exposure at levels above the MCL: increased
How much Dalapon is produced and released to the environment?
Dalapon is released directly to the environment in its use as a herbicide
for the control of annual and perennial grasses. Domestic production of
dalapon in 1982 ranged between 7 and 9 million lbs. active ingredient.
In 1984, its use in California was reported as follows: Non-food use,
92.9% (mostly on rights of way); main food crop treated was sugarbeet
(6.7% of total).
What happens to Dalapon when it is released to the environment?
Dalapon leaches readily in soil, though in some soils, microbes may break
it down fast enough to prevent ground water contamination. Still, a
persistence of six months has been observed in soils of various forests
and tree nurseries. Microbes will also degrade most of any releases to
water. Accumulation in aquatic life is not expected to be a problem.
How will Dalapon be detected in and removed from my drinking
The regulation for dalapon became effective in 1994. Between 1993 and
1995, EPA required your water supplier to collect water samples every 3
months for one year and analyze them to find out if dalapon is present
above 1 ppb. If it is present above this level, the system must continue
to monitor this contaminant.
If contaminant levels are found to be consistently above the MCL,
your water supplier must take steps to reduce the amount of dalapon so
that it is consistently below that level. The following treatment
methods have been approved by EPA for removing dalapon: Granular
How will I know if Dalapon is in my drinking water?
If the levels of dalapon exceed the MCL, 0.2 ppm, the system must notify
the public via newspapers, radio, TV and other means. Additional
actions, such as providing alternative drinking water supplies, may be
required to prevent serious risks to public health.
This is a factsheet about a chemical that may be found in some
public or private drinking water supplies. It may cause health problems
if found in amounts greater than the health standard set by the United
States Environmental Protection Agency (EPA).
Drinking Water Standards:
Note: This fact sheet is part of a larger publication
adapted from U.S. EPA publication: EPA National Primary Drinking Water
|Mclg: 0.2 ppm (parts per million)
Mcl: 0.2 ppm