Bladder Cancer and Chlorinated Water National Bladder Cancer
Study Shows Linkage
Friday, January 26, 2007 by: M.T. Whitney
(NaturalNews) Drinking, or even immersing yourself in, chlorinated water may increase your risk of bladder cancer, says a new study.
The new study is the first to suggest that chlorine is harmful to humans when ingested or absorbed through the skin, according to study leader Cristina M. Villanueva of the Municipal Institute of Medical Research in Barcelona and her colleagues.
Chlorine itself is not harmful, but its byproducts increase the risk of cancer. Trihalomethanes are the most prevalent by-product, and they can be absorbed into the body through the skin or by inhalation. When THM is absorbed through the skin or into the lungs, they hold stronger carcinogenic properties because they aren’t detoxified through the liver, Villanueva and her team found in their research.
Villanueva and her team surveyed 1,219 individuals with bladder cancer and 1,271 control individuals without the disease, polling them about their exposure to chlorinated water, including their bathing, swimming and tap water drinking habits.
The researchers also looked at the THM levels in the water systems of 123 municipalities.
People who live in households with more than 49 micrograms per liter of THM were at double the risk of bladder cancer versus households that have below 8 micrograms per liter of THM.
In industrialized countries, the common level is 50 micrograms per liter, the researchers note.
The researchers also found that use of swimming pools increased the risk by 57 percent and that people who drank chlorinated water held a 35 percent greater risk. Taking long showers and bathing also increases the risk in households that has water with higher levels of THM.
In the United States, an estimated 67,160 new cases of bladder cancer are expected to occur in 2007, and 13,750 deaths, according to statistics from the American Cancer Society.
“If confirmed elsewhere, this observation has significant public health implications in relation to preventing exposure to these water contaminants,” the researchers said in their report.
The study was published in the January issue of the American Journal of Epidemiology.
Bladder Cancer and Chlorinated Water
National Bladder Cancer Study Shows Linkage.
By Annette Keen
Probability link has been demonstrated between chlorinated water exposure and bladder cancer, according to findings published by the Environmental Epidemiology Branch of the National Cancer Institute in Bethesda, Md. the researchers say that, having currently undeterred bias, the risk factor in developing bladder cancer among people who ingested chlorinated water range from 12 to 27 percent, with risk escalating among smokers. One of the researchers, Kenneth Cantor, Ph.D. of the National Cancer Institute tells Water Technology that the linkage is based on data gathered over a period of a year and a half in the late ’70s.
The National Bladder Cancer Study involved some 9000 people from all over the country about 3000 bladder cancer cases and 6000 noncancer cases. Since then, researchers continue to analyze and evaluate the database. Associations are seen between the level of tap water consumption and the incidence of bladder cancer. “When we grouped the people according to what their source of drinking water had been,” Dr. Cantor explains, ” the risk was much, much stronger among people who had been drinking chlorinated water for much of their lives, as contrasted to those who had been drinking nonchlorinated water. Dr. Cantor says that in fact, the people who had been drinking nonchlorinated water showed No increase in risk with the increase in volume of ingested tap Water, “Cancer risk increased with the amount of consumed water,” he says, “but it was seen only in people who had been drinking chlorinated water most of their lives. Dr. Cantor’s conclusions have been published in the Journal of the National Cancer Institute.
Reason to Concern Several epidemiological studies have, during the past ten years, attempted to evaluate whether there is a link between chlorinated water ingestion and cancer. These studies were prompted by the widespread use of chlorine as a drinking water disinfectant and by the finding that carcinogenic substances, particularly the trihalomethanes, were formed in the drinking water because of chlorination. The suspected cancer sites have been the bladder, rectum, and colon. Many of these studies have been criticized for among other reasons, the potential for misclassifying exposure variables. With this in mind, the National Bladder Cancer Study considered 27 other risk factors for bladder cancer, along with chlorinated drinking water (see Table 1). Dr. Cantor says that the suspected carcinogenics lurking in chlorinated water are the trihalomethanes and the higher- molecular weight by-products.
Water Consumed per Day
Years of education
Hot tea consumption
Iced tea concumption
Daily tap water consumption
Daily Chlorinated tap water Consumption
Daily notap water consumption
Exposure to hazardous occupational materials
Pack-years of cigarette smoking
Use of chewing tobacco
Use of snuff
Pelvic area irradiation as a medical treatment
Use of artificial sweetners
Use of hair coloring products
Positive family history of uninary cancer
Past history of diabetes mellitus
History of blatter infection
History of kidney infection
Urban density index
World Health Organization
Chlorine in Drinking Water
EFFECTS ON HUMANS
Exposure to chlorine, hypochlorous acid, and hypochlorite ion through ingestion of household bleach occurs most commonly in children. Intake of a small quantity of bleach generally results in irritation of the oesophagus, a burning sensation in the mouth and throat, and
spontaneous vomiting. In these cases, it is not clear whether it is the sodium hypochlorite or the extremely caustic nature of the bleach that causes the tissue injury.
The effects of heavily chlorinated water on human populations exposed for varying periods were summarized in a report that was essentially anecdotal in character and did not describe in detail the health effects observed (26). In a study on the effects of progressively increasing chlorine doses (0, 0.001, 0.014, 0.071, 0.14, 0.26, or 0.34 mg/kg of body weight) on healthy male volunteers (10 per dose), there was an absence of adverse, physiologically significant toxicological effects in all of the study groups (27). It has been reported that asthma can be triggered by exposure to chlorinated water (28). Episodes of dermatitis have also been associated with exposure to chlorine and hypochlorite (29,30).
In a study of 46 communities in central Wisconsin where chlorine levels in water ranged from 0.2 to 1 mg/litre, serum cholesterol and low-density lipoprotein levels were higher in communities using chlorinated water. Levels of high-density lipoprotein (HDL) and the
cholesterol/HDL ratio were significantly elevated in relation to the level of calcium in the drinking-water, but only in communities using chlorinated water. The authors speculated that chlorine and calcium in drinking-water may interact in some way that affects lipid levels (31)
An increased risk of bladder cancer appeared to be associated with the consumption of chlorinated tapwater in a population-based, case–control study of adults consuming chlorinated or non-chlorinated water for half of their lifetimes (32).