What is Trichloroethane 1,1,2 (TCE) and how is it used?

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).

1,1,2-Trichloroethane (TCE) is an organic liquid with a chloroform-like odor. TCE is primarily used as a metal degreaser. The primary users of this compound are the automotive and metals industries. It is also found in some household products, such as typewriter correction fluid, paint removers, adhesives, and spot removers. It is also used to make vinylidene chloride which is in turn used to make synthetic fibers and plastic wraps such as Saran wrap.

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:

• Beta trichloroethane
• Beta-T
• Vinyl trichloride

Why is 1,1,2-TCE 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 (MCLG).

The MCLG for 1,1,2-TCE has been set at 3 parts per billion (ppb) 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 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 1,1,2-TCE to potentially cause the following health effects when people are exposed to it at levels above the MCL for relatively short periods of time:

• Irritation of gastrointestinal tract
• Red or hemorrhaged lungs
• Pale liver

Long-term: 1,1,2-TCE has the potential to cause the following effects from a lifetime exposure at levels above the MCL:

• Liver Damage
• Kidney Damage
• Cancer

Cancer toxicity:

Research indicates that TCE-induced carcinogenesis is complex, involving multiple carcinogenic metabolites acting through multiple modes of action. In 1985, EPA classified TCE as a probable human carcinogen. Three years later EPA reviewed information suggesting the weight-of-evidence was on a possible human carcinogen - probable human carcinogen continuum. Under EPA's proposed (1996, 1999) cancer guidelines, TCE can be characterized as "highly likely to produce cancer in humans." These findings are consistent with those of the International Agency on Research of Cancer (IARC, 1995) and the National Toxicology Program (NTP, 2000). As a result of the reassessment, EPA withdrew the inhalation and oral unit risk values.

Child Health Initiative:

ATSDR's Child Health Initiative recognizes that the unique vulnerabilities of infants and children deserve special emphasis with regard to exposures to environmental contaminants. Infants, young children, and the unborn may be at greater risk than adults from exposure to particular contaminants. Exposure during key periods of growth and development may lead to malformation of organs (teratogenesis), disruption of function, and even premature death. In certain instances, maternal exposure, via the placenta, could adversely effect the fetus. After birth, children may receive greater exposures to environmental contaminants than adults. Children are often more likely to be exposed to contaminants from playing outdoors, ingesting food that has come into contact with hazardous substances, or breathing soil and dust. Pound-for-pound of body weight, children drink more water, eat more food, and breathe more air than adults. For example, in the United States, children in the first 6 months of life drink seven times as much water per pound as the average adult. The implication for environmental health is that, by virtue of children's lower body weight, given the same exposures, they can receive significantly higher relative contaminant doses than adults.

How much 1,1,2-TCE is produced and or released into the environment?

An estimated 124 million lbs. of 1,1,2-TCE was produced in the US during 1974, based on the manufacture of vinylidene chloride. It evaporates during its use in the manufacture of vinylidene chloride and as a solvent. It is also released in wastewater from these uses, and in leachates and volatile emissions from landfills. The EPA estimates the gross annual discharge of 1,1,2-TCE waste in the US to be 4 million lbs.

What happens to 1,1,2-TCE when it is released to the environment?

When released into water, 1,1,2-TCE should primarily evaporate. In soils, it should partially evaporate and partially leach into the groundwater. Its break down by microbes, if it occurs, is very slow. 1,1,2-TCE shows little tendency to accumulate in aquatic life. Dissolved TCE's come out of solution or are "aerosolized" when water from a well or pressurized source is depressurized at a tap, showerhead, or other discharge point.

How will 1,1,2-TCE be Detected in and Removed from My Drinking Water?

The regulation for 1,1,2-TCE 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 1,1,2-TCE 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 1,1,2-TCE so that it is consistently below that level. The following treatment methods have been approved by EPA for removing 1,1,2-TCE: Granular activated carbon or with Packed Tower Aeration.

For Point of Use (POU) applications Reverse Osmosis systems and small in line carbon filters can be used, but must be maintained on a regular basis by the home owner. Reverse Osmosis systems have the added advantage that they essentially remove ALL other contaminants including heavy metals, nitrates, arsenic (As5), and any other dissolved solids.

How will I know if 1,1,2-TCE is in my drinking water?

If the levels of 1,1,2-TCE 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:

MAXIMUM ALLOWABLE TCE LEVELS IN DRINKING WATER AROUND THE WORLD (parts per billion - ppb)

• United States MCLG: 3 ppb
• MCL: 5 ppb
• Minnesota 5.0 ppb
• Arizona 3.2 ppb
• Florida 3.0 ppb
• New Hampshire 2.8 ppb
• Rhode Island 2.5 ppb
• Wisconsin 1.8 ppb
• New Jersey 1.0 ppb
• European Union 3 ppb

Questions and additional information about your water.

The above is probably more than you ever wanted to know about TCE, and may appear very frightening. However, thousands of system similar to yours (activated carbon tanks) have been installed all over the US, and have performed almost perfectly when properly maintained. You can drink and enjoy your treated water without worry. If you have any other questions about your water, or water treatment needs, please feel free to call on us. We have installed literally thousands of water treatment systems ranging from iron filters, taste and odor filters, reverse osmosis drinking water systems, water softeners as well as arsenic removal systems and, nitrate removal systems. Enjoy your water!