The most dangerous chemical compounds present in drinking water
We are living at a time when civilisation diseases are increasingly being talked about because, in addition to stress, they are caused by various chemical substances accumulated in excess in the environment. It should be noted that these diseases are not the result of maximum concentrations of toxins, but of microconcentrations (subtoxic concentrations), often unnoticeable but accumulating in the body.
Currently, civilization diseases include: cardiovascular diseases (hypertension, atherosclerosis, myocardial infarctions and strokes), allergic diseases in the form of skin allergy or bronchial asthma, mental diseases (as a result of damage to the most delicate tissue – brain tissue), cancer and chronic diseases of the respiratory system. A new field of expertise has emerged – environmental medicine (or clinical ecology). It draws attention to the ever-increasing number of hypersensitive people in whom even trace amounts of toxic substances, sometimes individual particles, in concentrations significantly below acceptable standards are able to cause disease reactions. Instead of adapting to harmful conditions, hypersensitivity is becoming more and more common.
Although the mechanisms of action of the individual toxic substances are very different, it can be said that they attack two fundamental directions for life:
metabolic processes to obtain and use energy,
transfer of genetic information to future generations.
Disruption of the first one leads to a decrease in the level of energy, which is manifested by the feeling of breathlessness and fatigue, even in people with full strength. We can even talk about the appearance of a new entity – an environmental disease, a decrease in physical strength, neuromotor disorders, a decrease in the intelligence ratio, sleepiness, apathy and a decrease in immunity.
The second direction concerns the transfer of genetic information, and the changes taking place are the result of the presence of mutagenic substances in the environment. They may be associated with the occurrence of congenital genetic defects, an increase in the number of spontaneous abortions, and an increase in the number of cancers. In addition to the health risks to the people who are currently living, this also poses a risk to the health of future generations.
Most environmental scientists believe that 85% of human cancer is due to continuous contact with substances in water and air. Carcinogenic substances are also considered not to have a harmful concentration.
The aim of this study is to present the nature and type of pollution toxic to humans contained in drinking water. Chemical substances enter the human body through the air (dust and fumes from factory chimneys), food (preservatives, dyes), but most often and in the greatest amount through the consumed water or other beverages made from it. Groundwater that fills wells, surface water that is a source of water for waterworks, and deep water that is a raw material for mineral waters (in recent years, over 500 new sources of water have been registered in Poland), are a kind of rubbish dump for all chemical compounds that water easily dissolves. Water supply plants have never been adapted to remove these compounds from the water – from the beginning of their formation at the turn of the 19th and 20th century, they were supposed, through disinfection of the water, to prevent diseases and epidemics caused by bacteria. It is a paradox today that none of the traditional methods of water treatment in these plants is able to effectively eliminate chemical compounds from them, but on the contrary new compounds are formed in them (and in the network of pipelines) as a result of the reaction of chlorine with organic compounds. The following are just some of the most dangerous chemicals commonly found in drinking water.
ASBEST
Asbestos is used as a sealing material in water and sewerage systems. It is used in the form of fabrics and ropes impregnated with grease and graphite; it is also used as an asbestos cement.
Asbestos fibres and dust are flushed away and into the human body with drinking water.
In the 1960s, thousands of kilometres of cement-azbestos pipes for the transport of drinking water were laid in Poland. These pipes have been in operation in many parts of the country so far. Consuming asbestos together with drinking water is not indifferent to the human body.
Asbestos is a very powerful carcinogen.
NITRATES AND NITRITES
The high nitrate content of the water has a negative effect on human health.
Nitrates may enter surface waters with municipal and industrial wastewater and also as a result of run-off from agricultural areas, which were fertilised with artificial nitrogen fertilisers.
Nitrites cause disturbances in the oxygen transmission process of the body through haemoglobin. The methemoglobin created as a result of their presence in the blood blocks the transmission of oxygen, causing cyanosis, a dangerous disease especially for infants.
Increased nitrate content in the water may cause chronic hypoxia, which may cause abnormal development of the body. Hypoxia is particularly dangerous for the developing fetus and for infants. It may manifest itself in the form of developmental defects, especially in the central nervous system, as well as mental retardation or underdevelopment. This has been confirmed by research carried out in Australia, where in some regions, due to natural reasons (geological deposits), the level of nitrates in waters is particularly high.
Increased nitrate content in drinking water can cause arterial hypertension and heart attacks. They have also been found to be carcinogenic. As a result of the reaction of nitrates with amines contained in food, N-nitrosamines, compounds with very strong carcinogenic activity, are formed in the gastrointestinal tract. The tumors caused by this group of compounds are mainly located in the stomach.
CHLOR
It is used in water treatment technology for disinfection. Since it was first used for this purpose (early twentieth century), the incidence of infectious diseases has decreased significantly. It has a very strong bactericidal effect, and by penetrating into a bacterial cell, it destroys its basic enzymes.
Unfortunately, in the 1970s it was stated that during the chlorination process organic chlorine compounds are formed which are very toxic to the human body. In addition, chlorine dissolved in water alone causes various diseases and damage to the body.
When taken orally (with drinking water), it causes mainly cancer of the urinary bladder and the rectum, where it lies with excretions. Upon contact with the skin it causes irritation, dryness, cracking and reduction of resistance to additional infections with fungi and yeasts. Organic chlorine derivatives, especially chloroform, can cause cirrhosis of the liver, liver and kidney cancer and sometimes tumours of the thyroid gland. Chlorinated phenol derivatives may cause leukaemia and lymphoma tumors. Chlorine and its derivatives interfere with the absorption of iodine, lowering it, and increase the rate of oxidation of unsaturated fatty acids, essential for the proper functioning of the body.
Despite many negative effects, “chlorination is still the most”, a common method of water disinfection. It is estimated that about half of the population in Poland uses chlorinated water.
CHLORATES AND PERCHLORATES
Sodium, potassium and calcium chlorates are pesticides, a group of so-called total herbicides that destroy all vegetation.
Surface water is supplied with run-off from areas where these compounds are used, e.g. railway embankments, roads, motorways, sports fields and industrial wastewater. They can also be found in drinking water, where the most common source is the chlorination of preozonised water.
Chlorates induce methemoglobinemia. Depending on the amount of methemoglobin in the blood, weaker or stronger tissue hypoxia occurs, which results in impairment of the function of various organs.
CHLOROFORM
In surface waters, it occurs as a result of contamination with sewage from the chemical industry.
Its presence in drinking water may be a consequence of insufficient purification of surface water abstracted for drinking purposes. Most often, however, it is formed when water is treated in a reaction between chlorine and organic substances of humic origin. Chloroform belongs to the group of compounds defined as halophorms and is classified as highly toxic.
It has a strong narcotic effect on the central nervous system. Causes visual disturbance, stunning and intoxication, dizziness, neuralgia, excitement, general loss of strength and stomach pains.
Harmful to metabolism and internal organs, may cause damage to and destruction of the liver and kidneys. As a result of kidney damage, diabetes occurs. It also disrupts the heart’s function. Chloroform is a known carcinogen. By acting on the skin, it causes inflammation and eczema.
CHLORAPHTHALENES
In surface water, they come from industrial wastewater.
They occur in drinking water as a result of inaccurately treated surface water or as a result of chlorinated naphthalene during the chlorine disinfection process.
Chloraphthalenes belong to the group of strong poisons; they are especially dangerous for children (up to 6 years of age), causing haemolysis of blood and plugging of kidney ducts. They can also cause damage to the liver and its pain, jaundice and skin changes in the form of rash.
CHLORINATED PHENOLS
Chlorinated phenols are pesticides, a group of fungicides (fungicides).
Surface waters are supplied with effluents from agricultural areas, where they were used, and sewage, mainly from the chemical industry.
In drinking water, they are formed when chlorinating surface waters containing phenols. Drinking water containing chlorophenols has a very intense, repulsive odour and taste, which is characteristic of these compounds.
Chlorophenols are a group of strong poisons acting on the nervous, circulatory and respiratory systems. They may cause leukaemia and lymphoma tumors as well as allergic changes in the skin and mucous membranes.
Tetrachloroetylen
It is discharged into surface waters with sewage. It is produced in large quantities by the chemical industry and is widely used as a solvent, particularly in the laundry industry.
It belongs to halophorms, a group of compounds formed in drinking water during treatment, if chlorination was used.
Fourchloroethylene is a chlorinated aliphatic hydrocarbon, a drug substance highly toxic to the central nervous system. It also causes damage to the peripheral nervous system, neuralgia, visual disturbance, stunning and intoxication. Prolonged exposure to this compound causes degeneration and damage to the liver, kidneys and heart muscle. Irritating to skin. It is classified as a carcinogenic substance.
DETERMINERS
These are chemicals that are widely used both in industry and in households, as they are part of washing powders, cleaning agents, washing machines, etc., and are also used in a wide variety of applications. They belong to the group of compounds which are very durable and difficult to biodegrade. Groundwater is found to be present even several years after introduction.
Surface waters are supplied with municipal and industrial wastewater, especially from the chemical industry, from factories manufacturing cleaning products, as well as from the laundry industry, the food industry, etc. They are found in drinking water as a result of insufficient surface water purification.
These compounds facilitate or even allow the absorption of other toxic substances from the gastrointestinal tract into the blood by their surface tension reducing properties (e.g. facilitated penetration of certain pesticides and polycyclic aromatic hydrocarbons, including benzo/a/pyrene carcinogenic).
Due to their physicochemical properties, detergents accumulate in fat cells or in cell membranes, where they interfere with the metabolism of fatty acids and damage membranes, which can lead to cell death. After entering the body, they have an allergenic effect and destroy the mucous membrane of the gastrointestinal tract, which causes non-rhinous states.
Long-term intake of detergents causes damage to the liver and adrenal cortex, where, in addition to the presence of tumors, disturbances in the production and release of adrenal hormones have been observed, which are the main regulator of metabolic processes. They have a very harmful effect on the skin, causing it to dry out, crack, irritate and eczema.
FENOL
Phenol occurs in surface water as a degradation product of organic substances. It often comes from industrial wastewater, e.g. from coking plants and the chemical industry.
It is very often found in drinking water as a result of inaccurate surface water purification.
Phenol is a strong poison. Irritating to the nervous and circulatory system. It damages the respiratory tract, causes denaturation (shearing) of proteins, has a very strong effect on the skin, causing necrosis consisting in initial bleaching, and after a few days – peeling. May cause methemoglobinemia – cyanosis, i.e. disturbances and inhibitions in oxygen transmission through haemoglobin.
During the treatment of water by chlorination, chlorophenols are formed, compounds with toxic properties which give off offensive smell and altered taste to drinking water.
GLIN (aluminium)
Surface, ground and deep water – depending on the geological structure and substrate type, they always contain certain amounts of aluminium. An additional source are industrial wastewater, sludge – water supply (resulting from the drinking water treatment process) discharged to rivers or sewage systems, from where it can also be discharged to surface waters.
In drinking water, aluminum occurs most often as a result of its improper treatment in the coagulation process using aluminum compounds, and this can be a major threat to the human body.
Clay is not one of the elements necessary for the functioning of the human body.
Aluminium salts, taken with water and food, are absorbed by the body, but are partially reacted with phosphates and excreted in the faeces. Clay, which has entered the human body through the gastrointestinal tract, accumulates in the bones, but does not accumulate in the tissues. Therefore, until recently, the aluminium content of drinking water was considered to be harmless to health. However, recent years have shown that the brain of people with epilepsy and dementia, including Alzheimer’s, contains a significant amount of aluminium compared to healthy people.
Statistical studies in England have shown that Alzheimer’s disease is likely to be dependent on the quality of water consumed with a content above 0.01 mg Al/l. 0,2 mg Al/l is allowed in Poland.
Aluminium is currently believed to be one of the factors causing disturbances in the structure and function of nerve cells, primarily the brain. An example is Alzheimer’s disease, a degenerative disease destroying cells in the central nervous system, associated with the occurrence of elevated concentrations of algae in the nervous tissue and body fluids. This is an irreversible process because the nerve cells do not recover and rebuild.
HALOFORMS
Haloforms are halogenated aliphatic hydrocarbons. THM methane trichlorofluorocarbons are a group of compounds comprising haloforms.
They are composed of organic substances, mainly humic compounds, during the treatment process in which chlorination is applied. Humic substances are so-called precursors of halophorms.
These are compounds with a very high toxicity and broad influence on the human body, and most of them are characterized by a strong carcinogenic and mutagenic effect.
A major risk is that the reaction to the formation of haloforms in drinking water is not only at the treatment site (water supply) but also in the water distribution network, and the further the water flows, the higher the concentration and the greater the variety. The formation process continues until one of the components of the reaction, chlorine or organic substance, is exhausted.
Preventing and eliminating such relationships is an extremely difficult, costly and complicated matter, not only in Poland, but also in the world. Change in treatment technology: replacement of chlorine by ozone, chlorine dioxide or chloramine, water aeration, use of carbon filters, etc. does not provide a full guarantee of halogen-free water supply.
The immense risk of halophorms in the water was first investigated in the USA in 1959, where a very high incidence and mortality from bladder cancer was found in New Orleans. The U.S. Environmental Protection Foundation has taken an interest in the matter and compared statistics on the percentage of deaths caused by cancer of the urinary tract and digestive tract in 64 districts in Louisiana. The comparison showed a clear correlation between drinking treated water from Mississippi and cancer mortality. In 1967, the carcinogenic activity of drinking water was studied in New Orleans. The analysis showed the presence of chloroform and more than 60 other compounds, many of which are considered to be carcinogens.
CDM
Cadmium enters surface waters along with industrial wastewater, most often from electroplating plants, chemical plants, metallurgical plants and ore enrichment.
The main source of drinking water is leaching it from PVC pipes, the production of which is used as a stabilizer of salts of heavy metals, such as cadmium. It is also washed out from pipes and other elements of the water supply system, e.g. from certain types of brass, soldering metals, cadmium-contaminated zinc (galvanised pipes).
Cadmium is a very toxic metal for the human body. It has the ability to accumulate, and delivering even small quantities of drinking water over a long period of time can be very harmful.
It accumulates primarily in the liver, kidneys, pancreas, thyroid gland, bones and hair. Particularly high accumulation has been found in the liver and kidneys, which causes serious damage to these organs. In excessive amounts, it damages the heart muscle and is also a carcinogen. In addition, cadmium causes changes in bone marrow function, nervous system disorders and hypertension, as well as deformation of the bone and skeleton. Cadmium accumulation in bones, known as Itai-itai disease (Japan, WHO 1972), leads not only to painful limb fractures, but also to degenerative changes in the skeleton, causing its deformation and disappearance.
PESTICIDES – PLANT PROTECTION PRODUCTS
They are divided into several groups with specific activities, the most important of which include
Excicides – to control mites,
Algicides – to control algae,
Insecticides – for insect control,
Herbicides – for weed control,
Fungicides – to control fungi,
Molluscicides – for slug pellets control,
Nematocydes – to control nematodes,
Rodenticides – to control rodents.
The huge spread of pesticides in agriculture has resulted in their accumulation in the environment (soil, water, air), as well as in living organisms, including humans.
These are harmful substances, and they often accumulate in the body, especially those with a very long decomposition period, which were used in the past (e.g. DDT, aldrin, dieldrin, etc.). The toxic effects of pesticides on the human body, as well as the long-term effects of low doses, are often unknown.
Their toxic effects depend on their chemical structure. They often contain metals such as arsenic, mercury, tin, which are themselves very harmful to the body. For example, preparations containing chlorinated hydrocarbons with cumulative properties and very difficult to break down both in the human system and in the environment were commonly used as insecticides. They most often cause kidney and liver damage, where they are detoxified and excreted. In the case of long-term (chronic) exposure to this group of insecticides, headaches, insomnia, irritability, concentration difficulties, sometimes nausea and stomach pains are present. Most of them show hepatoxic properties of different intensity.
Organophosphorus compounds (most often insecticidal preparations) may cause muscle weakness, damage the central nervous system, most often brain functions, especially in the mental sphere, slow down the process of thinking and weaken memory.
Many pesticides are attributed carcinogenic and mutagenic effects, as well as damaging to the nervous system. The liver is the organ most sensitive to carcinogenic pesticides.
Over the last several decades of intensive use, the range of protection measures has changed: some have been withdrawn for toxicity, longevity and resistance to insecticides (especially insecticides), others have been introduced. In fact, their number is growing rapidly, which in many cases makes it difficult to capture and determine their toxicity. The results of preliminary laboratory tests on animals cannot always be related to humans.
Efforts should therefore be made to limit the possibility of exposure (foodstuffs, water, air), which is easiest to do in the case of drinking water.
Pesticides – especially those that are resistant to physicochemical decomposition and biodegradation, as well as many others – permeate surface waters mainly with runoff from agricultural fields and are washed out of the air by precipitation. Moreover, in waters, especially bottom sediments, river and lake mules, some insecticides are still detected, most often of them very persistent, such as DDT (prohibited in Poland since 1974, but still active, as its biological decomposition period is 50 years).
Pesticides in drinking water may occur as a result of insufficient surface water purification.
POLYCYCLIC AROMATIC HYDROCARBONS (PAHS)
Substances posing a very serious risk to health include carcinogenic polycyclic aromatic hydrocarbons (PAHs).
Of the approximately 800 carcinogens known so far, PAH is the largest group, comprising more than 200 compounds. So far, more than 100 different compounds belonging to PAH have been detected in surface water. Examples include benzo/a/pyrene, naphthalene, anthracene, fluoranthene, crowns, pyrene and their derivatives. PAH are produced by incomplete combustion of organic substances, i.e. by a pyrolytic process, and naturally in nature. Through biochemical transformations, their formation was found in bacteria and plants.
The sources of PAH in the environment are mainly the petrochemical, coking and automotive industries, as well as heat plants, combined heat and power plants, household heating equipment and exhaust gases from cars and aircraft.
They are located in surface waters and come mainly from industrial and municipal wastewater. PAHs penetrate rivers, lakes and groundwaters, and even deep water, as pollutants washed away by precipitation from the air and from weathered asphalt surfaces.
PAHs are cumulative in the body and therefore exposure to even the smallest doses can be a cause of disease. Carcinogenic activity depends primarily on their chemical structure. PAH enters the body with food, drinking water and air. Depending on the route of insertion, there may be tumours of the entire gastrointestinal tract, and most often of the stomach; in the case of inhalation, lung cancer may be present. These compounds also act on the skin and through the skin, and by penetrating the body this way, they cause pathological changes. In the case of skin effects, there are redness, eczema, changes indicating a tendency to carcinogenesis and numerous cases of cancer.
In chlorinated drinking water, chlorinated PAHs are formed, e.g. benzo/a/pyrene is used to form a number of chlorinated PAHs, including chlorobenzene/a/pirene. However, it cannot be excluded that new compounds formed in the water will not turn out to the same extent or may be more harmful to the body than the starting compounds.
Dr Barbara Mikołajczak
Dr. Barbara Mikołajczak worked with water throughout her professional career. She worked for several years in water supply plants in Wrocław, then in the Provincial Sanitary and Epidemiological Station, and for the last years of her professional career – in the Institute of Environmental Protection. In all of these institutions she was responsible for researching surface water and drinking water pollution. He is a recognised specialist in the field of toxicology of chemical substances derived from drinking water in Poland. She is the author of the book entitled “The future of Poland. “Carcinogenic water”.