The Health Risks of Byproducts in Chlorinated Water (Trihalomethanes/THMs)

Chlorine has been an invisible protector of public health for at least a century, sterilizing our drinking water supplies to guard against waterborne diseases like cholera and typhoid, for example. It is one of the biggest public health successes in recent memory.

But this crucial safety step has an unintended ripple effect: the generation of chemical substances called disinfection byproducts (DBPs). Trihalomethanes (THMs) are one of the most frequent and troubling of these DBPs.

However, the standards for these compounds that your municipal water provider endeavors to limit legally do not always protect the customers as health-consciously as people want. Knowing what THMs are, how and where you're coming up against them, and the possible lasting health impact, is the first part of making sure your family's water is not only safe, but also healthy.

What are Trihalomethanes (THMs) and how do They Form?

Trihalomethanes are a group of chemicals that are formed when chlorine, the disinfectant, reacts with naturally occurring organic matter in natural forms, such as lakes and rivers. This organic material extends from decaying leaves and algae to tiny pieces of plant material. When chlorine is added to the treatment plant, it effectively neutralizes pathogens – but it also interacts with such organic material, creating THMs as a byproduct. The basic four THMs found in chlorinated water are:

• Chloroform.
• Bromodichloromethane.
• Dibromochloromethane.
• Bromoform.

The overall concentration of THMs, and different types of THMs in your tap water, can fluctuate significantly according to the area, season, water temperature, organic matter levels in the source water, chlorine concentrations in the municipality you are served by, and the type of your intake/contamination. Water treatment plants do monitor these concentrations, but not necessarily to zero, and regulations often trump elimination.

Exposure Pathways: Inhalation vs. Ingestion vs. Dermal Absorption

• Ingestion: People think of contaminants in water in relation only to the water they drink. But with THMs, ingestion is merely one aspect within a larger puzzle. Because THMs are volatile organic compounds (VOCs), they can easily vaporize from water to air, particularly when heated. The most common approach they take is drinking tap water. THMs go into your digestive system.
• Inhalation: This is the key route of exposure and is a common factor that goes under-recognized. Things like bathing yourself and taking a hot, steamy shower, running a dishwasher, boiling a pot of water on the stove, or even washing your laundry with hot water release THMs into your home air.
• Dermal Absorption: The body's biggest organ, your skin, can also absorb chemicals from water. With a long, hot bath or shower, those pores open, speeding up the rate of dermal absorption of THMs. This multi-pathway exposure means that your basic point-of-use filter on your kitchen sink won't do a lot to protect you from the immense exposure happening in your shower, bathroom, or in the steam draining from your dishwasher.

Known and Suspected Health Concerns Related to THM Exposure

The U.S. EPA currently regulates THM levels in public water systems because long-term exposure can cause a range of health effects. For instance, chloroform is classified as a probable human carcinogen. The risk associated with a single glass of water is negligible, although it's the cumulative effect of exposure that concerns people over many years. Long-term exposure to THMs has been associated with a variety of health risks, including:

• Increased Cancer Risk: High THM levels in drinking water have been associated with increased risk for bladder cancer in many studies. Some studies have also shown potential associations with colon and rectal cancers.
• Reproductive and Developmental Problems: Associations have been suggested between THM exposure and reproductive problems (i.e. miscarriage, low birth weight, and some birth defects).
• Liver and Kidney Issues: The liver, kidney, and central nervous system have been shown in animal model studies to be adversely affected by large amounts of THMs.

How Effective is a Standard Carbon Filter Against THMs?

People rely on widely accepted options such as a refrigerator or an activated carbon pitcher filter to enhance the quality of their water. The mechanisms involved in these filters are known as adsorption, where the carbon media with a porous surface traps contaminants. Whilst these filters are useful to inhibit flavor and smell of chlorine, they are not very effective against THMs.

The main drawbacks are the time to contact and capacity. Water runs through these tiny filters very fast, and that may be too short a window for the carbon to adsorb all the THMs. Finally, they are small enough that they are saturated and often need updating before being useful. More critically, they're point-of-use solutions, which means they only treat a limited amount of water for consumption, with none of the inhalation or dermal exposure that you find throughout the rest of your house.

Ensuring Comprehensive THM Removal With a Whole-House Carbon System

The only conclusive mechanism for protecting your entire family from THM exposure via all various routes is through whole-house carbon filtration systems. Located at the entryway of water into your home, these systems process each drop of water from every tap. A whole-house system provides:

• Total Protection: It removes THMs and chlorine before they ever get released into your home's air during a shower or absorbed through your skin in a bath.
• Superior Filtration: These big tanks have a giant bed of high-quality activated carbon. This provides a large storage area to adsorb and gives water a long 'contact time' with the media that can help in removing THMs and other pollutants.
• Peace of Mind: With a whole-house system, you no longer have to think about which tap is safe or the breath of air you're taking in the shower.

The solution: Through long-term and easy-to-maintain health benefits for your family. Don't leave your family's long-term health to chance. Call our experts now to schedule a free water analysis and discover how a comprehensive filtration system can create ultra-low-threshold protection from THMs and provide clean, safe water to every faucet within your residence. Contact a trusted water quality specialist today.