Why is 1,2-DCP 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 Goals.
The MCLG for 1,2-DCP has been set at zero 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
been set at 5 parts per billion (ppb) 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: EPA has found 1,2-DCP to potentially cause the following health
effects when people are exposed to it at levels above the MCL for relatively short
periods of time: damage to the liver, kidneys, adrenal glands, bladder, and the
gastrointestinal and respiratory tracts.
Long-term: 1,2-DCP has the potential
to cause the following effects from a lifetime exposure at levels above the MCL:
the liver, kidneys, bladder, gastrointestinal tract and the respiratory tract;
cancer.
How much 1,2-DCP is produced and released to the environment?
Production of 1,2-DCP has decreased greatly since a 1980 report of 77 million
lbs. Dow Chemical, the only listed producer, discontinued its production in 1991.
It may be released into the atmosphere or in wastewater during its production
or use as an intermediate in chemical manufacture. There were also significant
releases during its former use as a soil fumigant. It may also leach from municipal
landfills.
From 1987 to 1993, according to EPA's Toxic Chemical Release
Inventory, 1,2-dichloropropane releases to land and water totalled nearly 104,000
lbs. These releases were primarily from chemical industries. The largest releases
occurred in New York.
What happens to 1,2-DCP when it is released to
the environment?
1,2-DCP released to soil will largely evaporate. However,
it has been detected in groundwater. Releases to surface water will also evaporate,
and are not likely to accumulate in aquatic life.
How will 1,2-DCP
be Detected in and Removed from My Drinking Water?
The regulation for
1,2-DCP became effective in 1992. 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 1,2-DCP is present above 0.5 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 1,2-DCP so that it is consistently below that level. The
following treatment methods have been approved by EPA for removing 1,2-DCP: Granular
activated charcoal in combination with Packed Tower Aeration.
How will
I know if 1,2-DCP is in my drinking water?
If the levels of 1,2-DCP
exceed the MCL, 5 ppb, 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.
Drinking Water Standards:
Mclg: zero
Mcl: 5 ppm
1,2-DCP
Releases to Water and Land, 1987 to 1993 (in pounds):
=
Products of Superior Performance and Dependability 
