Water Contaminants Glossary
Access to clean drinking water is a fundamental necessity for health and well-being. However, tap water in the United States can sometimes contain various contaminants that may pose risks to human health. While water treatment facilities work to ensure that water meets safety standards, some unwanted substances can still make their way into the water supply. Among the contaminants commonly found in U.S. tap water, certain chemicals and by-products stand out due to their prevalence and potential health impacts. These include synthetic chemicals used in industrial processes, by-products of water disinfection, and substances that do not easily break down in the environment.
In this overview, we will discuss some of the top contaminants that have been detected in tap water across the United States. These contaminants include 1,2,3-Trichloropropane, Bromodichloromethane, Chloroform, Chromium (hexavalent), Dibromoacetic acid, Dichloroacetic acid, Haloacetic acids (HAA5 and HAA9), Perfluorooctanoic acid (PFOA), Total trihalomethanes (TTHMs), and Trichloroacetic acid. Each of these substances can enter the water supply through various means, such as industrial waste, the water disinfection process, or runoff from manufacturing sites. They have been associated with a range of health issues, including cancer, liver and kidney damage, reproductive effects, and other serious conditions. Understanding the sources and potential effects of these contaminants is crucial for taking steps to reduce exposure and protect public health.
1,2,3-Trichloropropane: 1,2,3-Trichloropropane is a synthetic chemical that can be found in industrial solvents, cleaning compounds, and varnishes. It is considered a carcinogen and can cause harm to the liver and kidneys. It typically enters drinking water through industrial waste or the improper disposal of waste products containing this chemical.
Bromodichloromethane: This is a trihalomethane formed as a by-product during the disinfection of drinking water, particularly when chlorine is used in the presence of organic matter. It's considered harmful because it has been identified as a potential carcinogen and may have other health effects such as impacts on the liver and kidneys. It primarily comes from the chlorination of water supplies.
Chloroform: Chloroform is another trihalomethane and a by-product of the chlorination process. It's a concern because it has been linked to cancer and potential reproductive effects. It is produced when chlorine reacts with organic matter in water.
Chromium (hexavalent): Hexavalent chromium is a toxic form of chromium that can be carcinogenic when ingested. It is often a by-product of industrial processes, such as metal plating and leather tanning, and can also occur naturally in the environment.
Dibromoacetic acid: This is one of the haloacetic acids (HAAs) that form when water is disinfected with chlorine, particularly when there are bromide ions in the water. It's considered harmful because it may have carcinogenic effects and can affect the liver, kidney, and reproductive systems. It comes from the water disinfection process.
Dichloroacetic acid: Another type of HAA, dichloroacetic acid, is a by-product of water chlorination. It's of concern due to its potential carcinogenic effects and possible liver toxicity. It is produced during the water disinfection process.
Haloacetic acids (HAA5): These are a group of five haloacetic acids that are monitored as a group in drinking water due to their potential health risks, which include cancer and reproductive issues. They are formed when disinfectants like chlorine react with natural organic matter in water. Some nitrogenous DBPs including haloacetonitriles, haloacetamides, and halonitromethanes are more toxic and carcinogenic than THMs and HAA.
Haloacetic acids (HAA9): This is a broader group of nine haloacetic acids, which includes the HAA5 and additional compounds. They share similar concerns and sources as HAA5, being by-products of water disinfection processes and potentially having carcinogenic and other health effects.
Perfluorooctanoic acid (PFOA): PFOA is a man-made chemical that is part of a group known as per- and polyfluoroalkyl substances (PFAS). It has been used in the manufacture of non-stick cookware, stain-resistant fabrics, and some firefighting foams. PFOA is a concern because it does not break down in the environment and can accumulate in the human body over time, potentially leading to adverse health effects such as thyroid disease, testicular cancer, kidney cancer, and reduced fertility. It can enter drinking water through contaminated soil and water runoff from areas where it was produced or used.
Total trihalomethanes (TTHMs): TTHMs are a group of four chemicals—chloroform, bromodichloromethane, dibromochloromethane, and bromoform—that form along with other disinfection by-products when chlorine or other disinfectants used to control microbial contaminants in drinking water react with naturally occurring organic and inorganic matter in water. TTHMs are a concern because they have been linked to an increased risk of cancer and may also cause problems during pregnancy.
Trichloroacetic acid: This is another type of haloacetic acid, which, like other HAAs, is formed during the disinfection of water with chlorine. It's a concern for the same reasons as other HAAs, such as potential carcinogenic effects and impacts on the liver and reproductive systems. It originates from the chlorination process in water treatment.