Consumer Factsheet on:
1,2,4-TRICHLOROBENZENE
List of
Contaminants
As part of the Drinking Water and
Health pages, this fact sheet is part of a larger
publication:
National Primary Drinking Water Regulations
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).
What is 1,2,4-TCB and how is it used?
1,2,4-Trichlorobenzene (1,2,4-TCB) is an
aromatic, colorless organic liquid. The greatest
use of 1,2,4-trichlorobenzene is primarily as a
dye carrier. It is also used to make herbicides
and other organic chemicals; as a solvent; in wood
preservatives; in abrasives. It was once used as a
soil treatment for termite control.
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:
Hostetex L-PEC
Trichlorobenzol
Why is 1,2,4-TCB 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 1,2,4-trichlorobenzene has been set
at 0.07 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 0.07 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: EPA has found 1,2,4-trichlorobenzene
to potentially cause the following health effects
when people are exposed to it at levels above the
MCL for relatively short periods of time: changes
in liver, kidneys and adrenal glands
Long-term: 1,2,4-Trichlorobenzene has the
potential to cause the following effects from a
lifetime exposure at levels above the MCL:
increased adrenal gland weights
How much 1,2,4-TCB is produced and
released to the environment?
Current production figures on
1,2,4-trichlorobenzene are not available. EPA
estimated 1983 production to be in the range of 3
to 8 million lbs., with imports over 3 million
lbs. Major environmental releases of
1,2,4-trichlorobenzene are due to its manufacture
and use as a dye carrier.
From 1987 to 1993, according to EPA's Toxic
Chemical Release Inventory, 1,2,4-trichlorobenzene
releases to land and water totalled over 180,000
lbs. These releases were primarily from textile
finishing industries. The largest releases
occurred in North Carolina and Virginia.
What happens to 1,2,4-TCB when it is
released to the environment?
1,2,4-Trichlorobenzene (1,2,4-TCB) binds well to
the soil and therefore will not leach appreciably
to the groundwater when released to land. However,
1,2,4-TCB has been detected in some groundwater
samples which indicates that it can be transported
there by some process. If released to water it
will largely evaporate within a few hours. It has
some potential to accumulate in fish.
How will 1,2,4-TCB be Detected in and
Removed from My Drinking Water?
The regulation for 1,2,4-trichlorobenzene 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 1,2,4-trichlorobenzene 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
1,2,4-trichlorobenzene so that it is consistently
below that level. The following treatment methods
have been approved by EPA for removing
1,2,4-trichlorobenzene: Granular activated
charcoal in combination with Packed Tower
Aeration.
How will I know if 1,2,4-TCB is in my
drinking water?
If the levels of 1,2,4-trichlorobenzene exceed
the MCL, 0.07 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.
Drinking Water Standards:
Mclg: 0.07 ppm
Mcl: 0.07 ppm
1,2,4-TCB Releases to Water and Land,
1987 to 1993 (in pounds):
Water Land TOTALS (in pounds) 157,541 22,835
Top Five States*
| NC |
80,253
|
13,209 |
| VA |
36,970
|
0 |
| GA |
17,639
|
8,951 |
| WV |
20,300
|
0 |
| NY |
1,150 |
1 |
Major Industries*
| Finishing plants, misc
|
52,249
|
0 |
| Finishing plants,
synth. |
47,976
|
0 |
| Weaving, finishing
mills |
20,139
|
8,951 |
| Alkalies, chlorine |
21,773
|
1 |
| Knitting mills, misc |
9,077 |
9,994 |
| Knit outerwear mills |
1,300 |
3,200 |
* Water/Land totals only include facilities with
releases greater than 100 lbs.
Learn more about your drinking water!
EPA strongly encourages people to learn more
about their drinking water, and to support local
efforts to protect and upgrade the supply of safe
drinking water. Your water bill or telephone books
government listings are a good starting point.
Your local water supplier can give you a list of
the chemicals they test for in your water, as well
as how your water is treated.
Your state Department of Health/Environment is
also a valuable source of information.
For help in locating these agencies or for
information on drinking water in general, call:
EPAs Safe Drinking Water Hotline: (800) 426-4791.
For additional information on the uses and
releases of chemicals in your state, contact the:
Community Right-to-Know Hotline: (800) 424-9346.
List of
Contaminants
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