Studies have shown this daily activity may increase the risk of developing cancer
As Dr. Strangelove
(1997) once said in a Kubrick’s classic, “A foreign substance is introduced into our precious bodily fluids without the knowledge of the individual. Certainly without any choice. That's the
way your hard-core Commie works.”
While there may not be a communist
plot to introduce “foreign substances
” into the bodily fluids of students at
Duke, students can unknowingly absorb harmful chemicals into their bodies by participating in a seemingly innocuous activity. This absorption occurs, not from doing drugs, drinking alcohol, or even
sexual promiscuity; rather from an activity that students are actually advised to do daily. A recent study has shown that a cancer-causing chemical found in chlorinated water can enter the blood stream by means of skin absorption and water vapor inhalation. Since chlorinated water flows through the shower heads in the bathrooms on Duke’s Campus, you may be absorbing a carcinogen every time you bathe. However, if you are informed of the risks involved with showering in chlorinated water, and perform the necessary safety measures, you can avoid becoming one of the estimated 200 to 1,000 people that die each year from cancers caused by the chlorinated water carcinogen.
What is in the Water?
Trihalomethanes (THMs) are formed by the combination of chlorine and naturally occurring organic material in chlorinated tap water. According to Amy M. Miles (2001), a former public health graduate student at UNC Chapel Hill, chlorination “saves countless lives each year by reducing risk from bacterial contamination”
(Lynberg). While chlorinating water is done to kill harmful disease-causing bacteria, this benefit comes at a price. THM is a carcinogenic substance that is associated with rectal, bladder and pancreatic cancers. Experts believe that by 2015 the death rate from these cancers will exceed that from lung cancer because of carcinogens present in our water and food
(Riddle, 2003). While exposure to THM accounts for a minimal percentage of deaths from these cancers, it is a contributor nonetheless. Overall, experts agree that there is a correlation between consuming chlorinated water and developing cancer
(Riddle, 2003).
How does THM get into my body?
You might think that drinking tap water from the local water fountain is the daily activity that results in the largest absorption of THM. However, you would consume as much chlorine into your body in a 10 minute shower as you would if you drank 2 gallons of tap water
(Riddle, 2003). The chlorine that enters your body would then combine with organic material to form THM. You might ask how THM gets into your blood stream while you’re taking a shower. Studies have shown that THM can be absorbed through the skin as well as inhaled through steam that evaporates from the water during a shower
(Riddle, 2003). A specific study was conducted by Amy M. Miles and Dr. Philip C. Singer, professor of environmental sciences and engineering at UNC, to test the blood of 50 women before and after showering to compare the levels of THM present. The study was conducted on 25 women in Corpus Christi, Texas, and 25 in Cobb County, Georgia to encompass both highly chlorinated THM
(found in Corpus Christi) and lower chlorinated THM
(Cobb County). The researchers found that in both locations, after showering, the average concentrations of THM in the women’s blood quadrupled the concentrations present before showering
(Lynberg, 2001).
What can I do about it?
The results of the study performed by Miles and Singer imply that absorption of shower water increases the risk of developing cancer. However, the risk is still minimal, and thus indulging in the occasional warm, soothing shower in the dorm bathrooms will not ensure that you develop cancer later in life. In addition, the daily stresses and demand that stem from the heavy workload and increased responsibilities you receive at Duke, frequently warrants a long, relaxing shower. However, just as there are measures that people take to prevent skin cancer from excessive sunbathing, there are safety procedures that you should take to reduce your risk of developing cancer from high THM levels in the blood.
One measure that can be taken is reducing the temperature of the shower water. By showering in cooler water, you reduce the inhalation of steam, and thus decrease the total absorption of chlorinated water into your blood stream
(Riddle, 2003). Another measure that can be taken to prevent high THM levels in your blood is to purchase
a shower filter or water filter. This will eliminate the primary source of chlorinated water
consumption and reduce your overall daily consumption of the carcinogen THM. Both of these tactics greatly decrease the THM absorbed into your body on a daily basis and thus significantly decrease the already minimal chance of developing cancer from this carcinogen.
Final Thought
Previously, you may have thought that that you had to smoke cigarettes, or bathe excessively in the sun to get cancer. However, even seemingly innocuous activities, such as taking a shower in your dorm bathroom, can present a risk for developing cancer. While performing the necessary safety measures decreases the already minimal risk of developing cancer from high levels of THM, it may not prevent it. Annual visits to the doctor and early detection are the most recommended tactics by experts to ensure a healthy, cancer-free life.
For more information, contact Julie Reynolds at julie.a.reynolds at duke.edu
Resources
1. Williamson, David. 2002. Study: Showering boosts concentrations of potentially
hazardous trihalomethanes. www.eurekalert.org/pub_releases/2002-05/uoncssb050202.php.
2. Stanley Kubrick : A Biography. 1997.
Vincent LoBrutto.
3. Dr. Riddle. 2003. Miracle Water.
www.miraculewater.com/WaterLibrary/Chlorine.html
4. Michele Lynberg. June 2001. “Assessing Exposure to Disinfection By-products in
Women of Reproductive Age.”
Studies have shown this daily activity may increase the risk of developing cancer 
