Chlorinated water: are short-term gains worth long-term pains?
by Cliff Turner
"The dynamic growth of chlorine chemistry during the 1950s and 1960s represents a decisive mistake in 20th-century industrial development, which would not have occurred, had our present knowledge of the environmental damage and health risks due to chlorine chemistry been available then." — German Council of Experts for Environmental Issues, 1990
Chlorine is considered a public health panacea, a cure-all. Popular opinion is that the benefits always outweigh the risks. No doubt that chlorine treatment of water is necessary in an emergency or for disinfection of water systems. But chlorine should not replace basic sanitation. A large chlorine residual in a water distribution system saves inspectors from looking for sources of contamination. Like other antibiotics, overuse can make the cure worse than the disease.
Chlorine is no longer effective in controlling some types of microorganisms. The fecal-oral route of bacterial life cycles has allowed some bacteria and their mutants to thrive. The organisms only need to evolve or perfect their defences to the barrier of chlorine. To do this, some bacteria form cysts or slime and some exist in a symbiotic relationship with microorganisms that can live in a chlorinated environment. For these reasons outbreaks of Cryptosporidium, Giardia, Helicobacter Pylori and other pathogens are simply not controlled by chlorine in our sewage or drinking water. It is reasonable to assume that over time more dangerous bacteria will develop these defences, especially if we allow the fecal-oral route of disease transmission to be checked only by chlorine.
Careless use of our surface and ground water for sewage disposal and for drinking water has resulted in BC's well- deserved reputation for the most water-borne illness in Canada. BC Health bureaucrats have mastered the art of denial and misinformation regarding these problems. The accepted Public Health reaction to the problem of sewage contaminated water is to add chlorine and go back to sleep.
The continued use of chlorine is justified by risk arguments comparing the short-term results of disease prevention versus the long-term chlorine side effects. The hazards of the Endocrine Disrupting Chemicals cannot be compared to the benefits of the control of water-borne diseases. Basic sanitation or other less harmful water disinfection methods can effectively control water-borne disease. But the damage from chlorine compounds is not as easily contained or evaluated.
Disinfection of drinking water (or sewage) is a use of chlorine with major health and environmental impacts. Chlorine combines with the organic matter in water to produce hundreds of organochlorine by products … The dirtier the water, the more compounds are formed. Among the best understood are the carcinogenic trihalomethanes (THMs), including chloroform. Chlorinated effluents from sewage plants and pulp mills have caused severe damage to fish and aquatic ecosystems. A number of studies have linked chlorinated drinking water to bladder cancer, colorectal cancer, birth defects, low birth weight, and changes in fat metabolism that can lead to high blood cholesterol and increased risk of cardiovascular disease. By relying on chlorine as a disinfectant, we have traded serious public health problems–infectious diseases–for new ones–chemically induced diseases … Some municipal drinking water systems are occasionally checked for THMs. But when the water is the dirtiest, and the THM levels would be high, the water is not tested.
In British Columbia, as in most jurisdictions, it is against the law to allow chlorinated drinking water to get into a fish-bearing watercourse. The toxic effects of chlorine compounds on aquatic life are well known. But what about irrigation systems using chlorinated drinking water, as is common in the Okanagan? What about water main flushing or fire fighting use of chlorinated drinking water and water main leaks and breaks? In BC, due to selective enforcement of environmental laws and some statutory exemptions, most transgressions are overlooked. Of course, if a small company or a working class citizen were caught spilling chlorine, the 'crime' would bring the full weight of the law with heavy penalties. For example, at the Walkerton Ontario investigation, the higher socio-economic suspects are praised (Medical Health Officer), while the lower-paid workers (the utility workers) are condemned, and even their pensions are cancelled. In a just society the blame would be placed on the individuals that knew the risks, and were being paid to protect the public.
* Cliff Turner is Executive Director of the British Columbia Ground Water Association and a graduate of the Ryerson Public Health Program.