Chloroform as a pollutant

Chloroform affects the central nervous system, liver, and kidneys. It was used as a surgical anaesthetic for many years before its harmful effects on the liver and kidneys were recognized. Short-term exposure to high concentrations of chloroform in the air causes tiredness, dizziness, and headache. Longer-term exposure to high levels of chloroform in the air, or in food and drinking water, can affect liver and kidney function. Toxic effects may include jaundice and burning urination. It is rapidly eliminated from the body. The US Department of Health and Human Services has determined that chloroform may reasonably be anticipated to be a carcinogen.

Chloroform can enter the body by breathing air, eating food, or drinking water that contains chloroform. Chloroform readily penetrates the skin and may enter the body by bathing or showering in water containing chloroform. Foods such as seafood, dairy products, meat, vegetables, bread, and beverages may contain small but measurable amounts of chloroform. Drinking-water supplies containing organic contaminants may contain chloroform as a by-product of chlorination of the water supply for disinfection purposes.

Chloroform is a colourless or water-white liquid with a pleasant non-irritating odour. Although it is a naturally occurring compound, synthetically production accounts for most of the chloroform found in the environment. Most chloroform is manufactured to make fluorocarbon-22, used a precursor for fluoropolymers and as a cooling fluid in air conditioners. Chloroform is also used in the manufacture of pesticides or dyes, or used in various products including fire-extinguishers, dry cleaning spot removers, and various solvents.

The primary sources of chloroform release to the environment are pulp and paper mills, pharmaceutical manufacturing plants, chemical manufacturing plants, chlorinated wastewater from sewage treatment plants, and chlorinated drinking water (water is chlorinated for disinfection purposes). Minor sources of chloroform release include, but are not limited to, automobile exhaust gas, use of chloroform as a pesticide, burning of tobacco products treated with chlorinated pesticides, evaporation during shipping and transport of chloroform, decomposition of trichloroethylene (a man-made product used primarily as a solvent), evaporation from chlorinated tap water during showering, evaporation from chlorinated swimming pool water, biological production of chloroform from marine algae, reaction of chlorinated pollutants with decayed vegetation, and burning of plastics.

Most of the chloroform released to the environment eventually enters the atmosphere, while much smaller amounts enter groundwater as the result of filtration through soil. Once in the atmosphere, chloroform may be transported long distances before it finally decomposes. Chloroform present in soil may come from improper land disposal of waste material containing chloroform or other chlorine-containing compounds that are broken down to form chloroform. People who work in businesses or industries where chloroform is found may be exposed to greater amounts of this compound than are members of the general population.

Chloroform is found in a wide variety of occupational settings as a result of its direct use in manufacturing processes, its use as a solvent for many different materials, and its formation during various chlorination processes. Occupational settings in which chloroform exposure may occur include: Chloroform manufacturing plants; Fluorocarbon-22 manufacturing plants; Ethylene dichloride manufacturing plants; Internal combustion engine industries; Pesticide manufacturing plants; Pulp and paper mills; Food processing industries; Paint stores (as a result of using chloroform-containing solvents for lacquers, gums, greases, waxes, adhesives, oils, and rubber).

The general population may be exposed to chloroform by breathing air and ingesting drinking water, beverages, and foods contaminated with chloroform. In addition, skin contact may occur during the use of various consumer products containing this compound or from exposure to chlorinated waters, such as swimming pool water. According to the USA EPA, more than four-fifths of the excess environmental risk of cancer in Philadelphia comes from drinking water contaminated chiefly by chloroform.