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Common Chemical Contaminants of Municipal Water



Municipal water supplies are often contaminated with a number of chemicals that could be hazardous to your health. Here we look at the most common and detail the ways in which they get into the water supply, and the health risks they pose.

Heavy metals
Radioactive Materials

Chlorine has been added to the water supply in western countries for decades for the purpose of killing bugs. The trouble is that chlorine has a number of negative consequences for humans as well. Amongst these are the fact that chlorine is a free radical initiator, elevates cholesterol and accelerates aging. These facts are bad news for anyone, since free radicals can lead to an increased risk of heart disease and various cancers, amongst other things, but it is even worse news for those with environmental illnesses. Browse our illness overview pages and you will quickly see that large amounts of research has confirmed that excessive free radical production plays a major role in all of these illnesses, from chronic fatigue syndrome to autism. It is therefore wise to avoid any further sources of free radicals, including chlorinated water, if you suffer from any of these conditions. It is not just drinking tap water that causes a problem either, in fact, you take more chlorine into your body through your skin when you shower or bath than you would from drinking 8 glasses of tap water. Hot water also vapourises the chlorine creating a toxic mist that can cause immediate reactions in those with chemical sensitivities and exacerbate other environmental illnesses. A series in a national UK newspaper in 2004 reported that chlorine added to municipal swimming pools created a toxic cloud that hovered above the pool and caused an increase in asthma and other allergic conditions in children using the pool. This report was validated by a study conducted by The Catholic University of Louvain, Belgium, and published in the Occupational and Environmental Medicine journal in July 2006. The study involved nearly 190,000 children aged 13 and 14 from 21 different European countries and found that rates of childhood asthma and wheeze rose by around 2-3% for every indoor swimming pool per 100,000 people. The researchers stated that the long-term effects of chlorine by-products on children's respiratory health should be thoroughly studied, and that swimming pools should be properly ventilated and levels of chlorine by-products regulated.

Another potentially hazardous chemical added to drinking water supplies, is fluoride. Fluoridated water is a highly controversial subject since there is no reason for adding it to protect us from anything in the water supply, as is the case with chlorine. Fluoride is added to water based on the contestable idea that it makes us healthier, specifically our teeth. It is suggested that adding fluoride to our water supply (and toothpastes) leads to stronger teeth and less tooth decay, yet an 11 year study of 39,000 US schoolchildren found no statistically significant differences in tooth decay between children drinking fluoridated water and those drinking non-fluoridated water. There are a number of good reasons why fluoride should not be addd to water supplies however. Fluoride is a halogen but acts much like a heavy metal in potently inhibiting and damaging important enzymes. It can also cause cellular dysfunction and damage hormone receptors and other regulatory sites if it makes its way into cell membranes. Of particular importance with regards to autism and other behavioural disorders is the news that fluoride damages enzymes within the brain and lowers IQ's. Furthermore, there is evidence that fluoride causes excessive calcification in arteries, joints and ligaments. It has also been implicated in an increase in hip fractures and bone cancers due to it's accumulation in bones at the expense of calcium (skeletal fluorosis).

Pesticides inevitably ends up in our water supply as the run off from fields where crops are sprayed makes it's way into reservoirs. A major class of pesticides are the organochloride pesticides that include more than 15,000 chlorinated compounds. Included in this class of chemicals is atrazine which is widely sprayed onto grain crops, fruit and vegetables. Others include DDT, chlordane and lindane, which rather worryingly, is the main ingredient in the head lice lotions we innocently rub into our young children's scalps. All of these pesticides are highly damaging to the endocrine, immune and detoxification systems of the body. What makes pesticides truly hazardous is the fact that many cannot be completely detoxified by the body and therfore accumulate in the tissues where they continue to cause dysfunction and disease. Of course, with this being the case, every time you drink water contaminated with pesticides, you are adding to the toxic burden within your body and increasing your chances of disease, or potentially exacerbating an existing condition. Research carried out by Dunstan and colleagues in 1996 showed that a number of people with persistent fatigue had much higher than average levels of organochloride pesticides in their red and white blood cells, that may have been contributing to their illness. Multiple chemical sensitivity victims commonly report that their illness started following acute exposure to pesticides, and animal research has shown that pesticides (and other chemicals) can sensitize certain areas of the brain and reproduce the symptoms and brain abnormalities displayed by MCS sufferers. Dr. Sherry Rogers, an expert on MCS and the effects of chemicals on human health states that pesticides are the single most hazardous class of chemicals and the cause of a vast array of health complaints in our society today. It is hard to disagree.

Like pesticides, our water supply is often contaminated with varying levels of fertilizers that have run off from agricultural land. Fertilizer use has increased by a factor of 10 since World War II and many consider the amounts used to be far in excess of what can resonably be expected to be taken up by the crops they are applied to. In California, a massive 200kg/hectare/year or more is used on corn and other crops. The major chemical ingredient of fertilizers is nitrogen, in the form of nitrate, and this can have a serious impact on health when ingested. Levels in drinking water are frequently found to be above safe levels set by governments in industrialized countries. Nitrate is converted into nitrite in the body, which in turn lowers the blood cells ability to carry oxygen. This prevents oxygen from reaching the brain, which can be fatal, especially in infants drinking formula where it can lead to so called 'blue baby syndrome'. In people with environmental illnesses, poor oxygen transport and utilization is already an issue, causing fatigue and muscle aches for example, so chronic exposure to nitrate in drinking water can only serve to exacerbate the problem. Nitrate has also been strongly linked to gastric cancers.

Heavy Metals
Heavy metals are byproducts from industrial processes and consumer waste. Some of the most prevalent in water supplies are mercury, lead and cadmium. The most unsettling thing about their effects on health is the fact that the body finds it very difficult to excrete them. Heavy metals therefore accumulate in the tissues of animals, including humans. This is why predatory fish, high up on the food chain, such as tuna, often contain such high levels of mercury. Once these metals build up in the tissues they interfere more and more with normal biological processes. High glutathione activity is needed to have a chance of coping with chronic exposure. Unfortunately, those with environmental illnesses have been found to have lower than normal glutathione levels, so avoiding exposure as much as possible is essential.

Mercury - is widely used in industrial processes, such as the production of chlorine and non-ferrous metals. It is found in various products, such as batteries, fluorescent light bulbs and thermometers. Once elemental mercury escapes into the environment and enters the water system it can be transformed by natural processes into methylated forms, mainly monomethylmercury and dimethylmercury, which are highly toxic. In 2004 EPA studies show that in the United States, one of every three lakes and one-quarter of the nation's rivers contain enough pollution that people should not even think about eating fish caught in these areas, nevermind drink the water. Mercury is a potent neurotoxin which damages the nervous system and results in symptoms such as mood swings, mental changes, hallucinations, memory loss, nerve damage and the inability to concentrate. It is linked to immune system impairment and disruption of enzymes. Mercury has also been implicated in environmental illnesses including chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivity and resistant Candida infections. Further to this, Bernard et. al, in their paper "Autism: A Unique Type of Mercury Poisoning", reveal a startling similarity between the symptoms of autism and mercury poisoning.

Lead - is used in a wide range of products including batteries, gasoline additives, rolled and extruded products, alloys, pigments and compounds, cable sheathing, shot and ammunition. The main source of lead contamination in the domestic water supply however, is from leading pipes and plumbing fixtures. Soil and dirt also contains lead to some degree so it can be washed into rivers and waterways by heavy rain. When consumed, lead can cause serious damage to the brain, nervous system red blood cellsand causes various effects. High levels of exposure can also disrupt enzymes and other biochemical processes and result in damaging effects on the kidneys, gastrointestinal tract, joints and reproductive system. In one study involving chronic fatigue syndrome patients, it was found that 49% showed lead hypersensitivity (45% also showed mercury hypersensitivity). This finding is likely to be similar in sick gulf war veterans who may have been exposed to large amounts of lead and other heavy metals. Many studies have shown that lead impairs immune function.

Cadmium - is found in water supplies as cadmium chloride and cadmium sulphate. Cadmium is used in a number of industrial processes, including welding and soldering, and production of iron, steel, zinc and cement. It's most widespread use however is in nickel-cadmium batteries which are used in cordless electronics. Cadmium may end up in the water supply as a result of any of these industrial processes. It is also present as an impurity in organophosphate fertilisers, so may enter the water system through run off from agricultural land. The health dangers of cadmium are a result of it's chemical similarity to zinc, an essential micronutrient. Chronic ingestion of cadmium from the water supply may cause symptoms such as gastrointestinal disorders and flu-like illness. Eventually it can cause kidney failure, as most heavy metals can. Cadmium is also a strong carcinogen (cancer causing agent) and has been linked to bone diseases such as osteoporosis. As with the other heavy metals, cadmium has been associated in a number of studies, with impairment of the immune system and reduction in a persons ability to fight off infection. As such it has been implicated in chronic fatigue syndrome, fibromyalgia and other environmental illnesses. Cadmium has also been shown to lower levels of the active thyroid hormone, T3, whilst the TSH levels which most thyroid tests measure, remained normal. As a result you could have poor thyroid function (coomin in EI's) due to cadmium poisoning and standard thyroid tests would miss it. Infants and children are most susceptible to damage from heavy metals, so cadmium along with other metals such as mercury are being studied for their involvement in autism and other developmental disorders.

Petrochemicals - such as gasoline, diesel and benzene may contaminate the water supply by leaking from underground storage tanks. In 1996 the city of Santa Monica, California, was forced to shut down a large part of it's drinking water supply due to MTBE contamination. MBTE is a gasoline additive and was detected at levels of up to 600 parts per billion in Santa Monica's water; the safe limit set by California's Environmental Protection Agency is only 35 parts per billion. The contamination was blamed on leaking undergrowund gasoline tanks close to wells from which much of the city's water was supplied. MTBE, or or methyl tertiary butyl ether, remains dissolved in water for a long time and may attach to particles in the water which will eventually cause it to settle to the bottom sediment. MTBE is a known human carcinogen and studies with rats and mice suggest that drinking MTBE may cause gastrointestinal irritation, liver and kidney damage, and nervous system effects. Benzene is another petrochemical that may end up in water supplies as it is widely used in industry and consumer products such as paint thinners. The Foundation for Water Research, based in England, untertook a study and found reported contamination incidents, involving mainly benzene, trichloroethene, and tetrachloroethene, across six countries spanning l956 to 1994. They found that these chemicals could permeate some of the newer plastic pipes used by many water companies, and enter the domestic water supply. Benzene is a Class A carcinogen (one of the strongest cancer causing chemicals) especially associated with leukemia. Long term chronic exposure to benzene is also associated with haematological problems, and can affect the bone marrow, which is the tissue responsible for producing blood cells. Some of the problems that can develop include excessive bleeding, immune system deficiencies, and anemia. Petrochemicals are based on hydrocarbons, molecules containing hydrogen and carbon atoms. It has been suggested that hydrocarbons cause the symptoms associated with multiple chemical sensitivity due to their structural similarity to excitory neurotransmitters, chemicals that increase activity in the brain. Symptoms of multiple chemical sensitivity can almost exclusively be attributed to autonomic nervous system dysfunction. It has also been shown in rodents that chronic exposure to hydrocarbons, through contaminated water supply for example, causes a sensitization of brain cells in the limbic system. This eventually results in multiple chemical sensitivity as brain acitivity is triggered by lower and lower levels of hydrocarbons encountered in the environment.

Dioxins - are organic environmental pollutants which are thought to be some of the most toxic chemicals known to man. Dioxins are compounds produced during chlorine bleaching, paper production processes, waste incinerators, production of pesticides and the burning of wood for fuel. Although originally thought to be entirely manmade chemicals it is now understood that dioxins can also be produced in nature through events such as volcanic eruptions and wild fires. Dioxins are a major health hazard when in the air but what is less well known is that dioxins in the air can also enter the water supply through fog and rain. In 2001, The Saratoga News reported that the Environmental Protection Agency had labelled the San Francisco Bay area as a polluted body of water due to dioxin contamination. It was thought that the high levels of dioxins in the bay were partly the result of the popularity of using wood burning stoves for heating homes in California. Rolf Halden, PhD, PE, is a researcher at the Department of Environmental Health Sciences and the Center for Water and Health at the Johns Hopkins Bloomberg School of Public Health. Dr. Halden states that "Exposure to dioxins can cause chloracne, a severe form of skin disease, as well as reproductive and developmental effects, and more importantly, liver damage and cancer." Dioxins are everywhere in our environment in the modern world, including our water supply, and US governmental studies have shown that nobody is free from them. A paper published by Cynthia Washam demonstrates that dioxins also damage the brain and specifically reduce motivation. The studies she references were carried out on rats but the researchers point out that many people have levels of dioxins equivalent to that which caused behavioural changes in rats.

Radioactive Materials - emit radiation which damages cells, including the DNA they contain, and can lead to mutations and cancer. With respect to radioactive materials contaminating water supplies, in 1999 levels of radioactive isotopes radium-226 and radium-228 in excess of the U.S. Environmental Protection Agency standard for drinking water were detected in northern parts of Illinois. The contamination is thought to have been due to an aquifer flowing over highly radioactive rock before being stored for domestic water supply. As well as contamination from natural sources, manmade radioactive materials may end up in water supplies. In May 2006 Greenpeace reported that the water supply in the Champagne region of France, famous for it's sparkling wine, was being contaminated by radioactive waste from nearby storage facilities. The radioactive waste included isotopes of plutonium. As power generation from nuclear sources continues or even expands, problems of radioactive waste and water supply contamination can only be expected to increase. The danger to health from radioactive materials depends upon the particular chemical in question, especially on it's rate of decay, or half-life. A radioisotope such as plutonium remains radioactive for a long time so if it accumulates within the body it will continue to cause damage for many years unless it can be excreted. As an example of specific health hazards from radioactive material, the thyroid gland takes up a large percentage of any iodine that enters the body. Radioactive iodine is a common component of nuclear waste from power stations, such as that leaking into the Champagne water supply. If large quantities of radioactive iodine are inhaled or ingested, the thyroid may be impaired or destroyed.

Microorganisms - can spread many diseases through water supplies. Some common water born diseases include:




Bacterial Infections

Paratyphoid fever
Bacillary dysentery

Viral Infections

Infectious Hepatitis (jaundice)

Protazoal Infections

Amoebic dysentery


Human and animal wastes are a primary source of disease causing microorganisms in water supplies. Sources of contamination can include runoff from feedlots, pastures, dog runs, and other land areas where animal wastes are deposited. Water supplies can also become contaminated due to seepage from septic tanks or sewage treatment facilities, and by natural soil/plant bacteria. Flooding is another major cause of contamination. Water companies are obliged by the law to routinely test their supplies for microorganism levels but even the "safe" levels may pose a threat to susceptible groups and levels may sometimes rise above legal limits.


Disease causing microorganisms such as those responsible for typhoid, hepatitis and cholera are rarely encountered in developed nations thesedays but more minor intestinal infections do occur through the drinking of contaminated water. In healthy individuals these are not much of a concern, in infants, the elderly and those with poor immune function such as environmental illness sufferers, such an infection can be rather more serious.



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