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Compare water filters by water contaminant

Browse common water contaminants to compare water filter cartridges that reduce or remove them from your drinking water


Overgrowths of Algae in water, known as algal blooms, can be blue, red or brown and can be both toxic and nontoxic. Harmful algal blooms can produce extremely dangerous toxins that can cause illnesses and even death in people. 



Aluminium is Earth’s most abundant metallic element, found in over 8% of Earth’s crust and has many practical usages for example in the automobile, construction and aircraft industries to produce metal alloys. Aluminium is a naturally occurring water contaminant, however, it has not been proven to have any long term negative health related effects, but short and high term exposure can cause short-lived symptoms such as nausea, vomiting, diarrhoea, mouth ulcers, skin ulcers and skin rashes. There are also concerns that aluminium can contribute to senile dementia, but this has not been clarified.



Antibiotics are useful for preventing and treating bacterial infections in human beings. Molecules with antibiotic properties have been attacking bacteria naturally long before human beings discovered the effectiveness of antibiotics. Man-made antibiotics can enter drinking water as a byproduct of the production of pharmaceutical ingredients or by the unsafe disposal of medicines by consumers. Although antibiotics are used to treat or prevent illnesses, and under ideal circumstances, they help to destroy bacteria in drinking water, more persistent antibiotics have been found in drinking water, namely trimethoprim and sulfonamide, macrolide, quinolone, and tetracycline.  While there’s little evidence to suggest that antibiotics being ingested by human beings is directly harmful, indirectly they promote resistance development in human pathogens and therefore make stronger and more harmful bacteria in the environment.



Arsenic naturally occurs in rocks and soil, because of this, small amounts can dissolve into groundwater that can become drinking water. Drinking water with Arsenic over prolonged periods of time can cause illnesses such as cancers of the bladder, lungs, liver and other organs. Additionally, Arsenic can be associated with diabetics. 



Asbestos is a general term for fibrous silicate minerals containing iron, magnesium, calcium or sodium. There are two main groups of fibrous silicate minerals, namely, serpentine (e.g chrysotile) and amphibole (e.g. amosite, crocidolite, and tremolite). Asbestos, when inhaled, is widely accepted to cause respiratory and other illnesses such as asbestosis, bronchial carcinoma, malignant mesothelioma of the pleura and peritoneum, and possibly cancers of the gastrointestinal tract and larynx .  However, while Asbestos can become airbourne if present in drinking water, it’s not thought to be harmful whether inhaled or ingested this way.



The herbicide known as Atrazine, is most commonly used to control broadleaf and grassy weeds among row crops such as corn, sorghum and sugarcane.  Atrazine enters groundwater after being used for agricultural purposes. Consumption of Atrazine may cause human health problems, such as a cause of cancer and reproductive problems.



Bacteria are a major water quality concern throughout the world. Bacteria are naturally present in water and can cause waterborne diseases such as diarrhoea and gastrointestinal illnesses. 

  • [0] Department of Population Health and Reproduction, Department of Agricultural and Biosystems Engineering, Department of Biological and Agricultural Engineering & Zachry Department of Civil Engineering. Available at: [Accessed 21st of July 2018].


Bentazone is a herbicide that is used to control broadleaf weeds and sedge weeds for food crops such as soybean and corn. It enters the environment when it is applied to control weeds among crops.  Short exposures to Bentazone can cause fetal death, while longer exposure is associated with anaemia and other blood system complications.



Benzene is a colourless liquid that has a characteristic odour. The primary use for Benzene is in the chemical industry, it is used to produce styrene/ethylbenzene, cumene/phenol and cyclohexane.  Benzene contaminates water by atmospheric deposition, spills of petrol and other petroleum-based products, and chemical plant effluents.  A small exposure of Benzene in high concentrations affects the central nervous system and can even cause death.  It is thought that considerable amounts of exposure to benzene can cause Leukaemia, preceded by pancytopenia, or aplastic anaemia.



Bromodichloromethane is a colourless, heavy, nonburnable liquid that is usually found evaporated in the air or dissolved in water that does not usually exist as a liquid in the environment.  However, since Bromodichloromethane is a byproduct of adding chlorine to drinking water to kill any disease-causing organisms, it can enter the environment this way.  It is not currently known what harm human exposure to Bromodichloromethane there is, but studies of animals have shown liver and kidney damage and impaired fetal development.



Bromoform is used in geological tests as a fluid to test for mineral ore separation, additionally, it is used as a laboratory reagent and in the electronics industry for Quality Assurance. Traditionally, Bromoform was used as a solvent for wax, grease, oils and additionally in fire-resistant chemicals and in fluid gauges.  Drinking water disinfected with chlorine, bromine or bromine compounds can be a route to human exposure.  The short-term exposure to high levels of Bromoform can affect the nervous system and slow down brain functions,  it can also injure the kidneys and liver. Long-term exposure to high levels of Bromoform have not been fully studied, however, animal studies suggest that it can affect the liver, kidneys and central nervous system. Other incomplete studies suggest a positive correlation between levels of Bromoform in drinking water and the incidence of several tumour types, but this research is inconclusive.



Cadmium occurs naturally in the Earth’s crust and soil, it has many practical uses such as in batteries, paints, pigments, coatings and some types of inexpensive jewellery.  Low-level exposure to cadmium can decrease bone density, especially in growing bones in children. Cadmium also tends to build up in the kidney and is not filtered out of the body, and lifetime exposure can cause kidney disease.



Calcium is an alkaline metal that is essential for living organisms to survive, it is derived from nearly all rock with the greatest concentrations being in limestone and gypsum. Almost all  (99%) of calcium within a human body is stored within bones and teeth, while the remaining 1% serves as a signal for vital physiological processes in human metabolism. Calcium makes hard water and is often filtered out of drinking water to prevent limescale. Calcium is not usually harmful to humans but too much can cause stomach pain and diarrhoea.



Carbofuran is a white crystalline solid that is used worldwide as an insecticide, acaricide and nematicide. It’s rarely found in water. There has been no research into the effects of ingestion by humans via drinking water, but a report of three female farm workers that suffered from vomiting, lassitude, nausea and hypersalivation suggest it can become toxic to human beings if ingested.



Chlorine is a pale green reactive gas which was used as a chemical warfare agent during World War 1, but it now used to disinfect water in the developed world and therefore enters drinking water via the disinfection process.  While usually safe, Chlorinated water has been associated with an increased risk of bladder cancer over long periods of time.



Chloroform, also known as trichloromethane,  is a chemical that is used to make other chemicals and a byproduct of chlorinating water.  It can be found in groundwater, surface water and drinking water. Since Chloroform is used to treat water and reduce the risk of illness from bacteria and viruses, most people are exposed to it in their drinking water. Long-term exposure to chloroform can damage the liver and kidneys.


Chromium 6

Chromium is an odourless and tasteless metallic element found naturally in rocks, plants, soil, volcanic dust and animals. Chromium-6 is a hexavalent chromium, which is a term used in chemistry to describe the property of an element that determines the number of other atoms which an atom of the element can combine. Chromium-6 is found in the environment naturally due to the erosion of natural chromium deposits, but it can also be man-made as part of industrial processes. Other ways Chromium-6 can enter the environment is by leakage, poor store or inadequate industrial waste disposal practices.  Long-term exposure to Chromium-6 can result in allergic dermatitis.



Copper is a naturally occurring, used to make many products including plumbing systems, therefore, it can enter drinking water through household plumbing systems. Consuming copper long periods of time can cause a variety of illnesses, such as vomiting, diarrhoea, stomach cramps, nausea, liver damage and kidney disease.



Cryptosporidium is an intestinal parasite, a protozoan, which is a slightly more complex type of organism than a bacterium or a virus.  Cryptosporidium is responsible for the illness called Cryptosporidiosis, which is the infection of the intestine where the organism emerges from its shell, called the oocyst. Cryptosporidium is commonplace in rivers and lakes, especially in waters contaminated by animal waste. The main symptoms of Cryptosporidiosis are diarrhoea, nausea, vomiting and abdominal cramping. In people with weaker and more vulnerable immune systems, Cryptosporidiosis can become a cause of death.



Detergents are artificially created cleaning products that are regularly used to wash clothes worldwide, and they’re usually used in their powder or liquid forms. Detergents can enter drinking water due to how frequently they are used by human beings. However, in water contaminated by powdered detergents, there is a significant increase in levels of certain chemicals such as chloride, sulphate, carbonate and bicarbonate, while liquid detergents similarly contaminate water, it is a nominal increase. Preliminary reports suggest that cancer-causing chemicals such as NDMA and other nitrosamines can be created during the disinfection process.



Dibromochloromethane (DCFM) is an industrial chemical used as a propellant, refrigerant, fire extinguisher and solvent and is a colourless liquid or gas with a sweet odour. DCFM is thought to contribute to the depletion of Earth’s Ozone layer and is under an international agreement to be phased out by 2030.  DCFM most commonly contaminants water draining from landfills and at hazardous waste sites. There have been no studies on the health effects of DCFM in drinking water but it is thought to be less toxic than Chloroform.



Dinoseb is a pesticide that was used among crops such as soybeans, and corn to control weeds, fungus and insects.  It is no longer legal to use in agriculture due to the risk of birth defects and male reproductive problems. The risk of contaminated drinking water is thought to be unlikely. 



Endrin is an insecticide used against agricultural pests and is particularly effective against butterflies and moths (Lepidoptera). It is mostly used on cotton but has additional uses amongst rice, sugar-cane, maize and other crops. Additionally, it can be used as a rodenticide. Endrin is rarely found in water used for human consumption, however, exposure to a toxic dose of Endrin can cause signs and symptoms of intoxication as excitability but also convulsions. If the appropriate treatment is not given to a person that has been intoxicated by Endrin then death may follow.


Fine Solids

Fine solid is a term used for particles with a diameter between 2 and 75 microns. Examples of fine solids are silt, coarse clay, organic fines, and phytoplankton. Fine solids get accumulated in the water through industrial discharges, sewage, fertilizers, road runoff, and soil erosion. There is no known direct hazard to health. Nevertheless, in high concentration fine solids in drinking water can act as the carrier of toxins and affect the taste of water.



Giardia is a microscopic parasite that lives in the intestine and causes Giardiasis which is a diarrhoea illness. Brace yourself though… millions of Giardia can be released by the bowel movements of an infected human or animal and this waste can enter water wells during periods of flooding.



Glyphosate is a herbicide used in agriculture, forestry and aquatic weed control. The usage of Glyphosate can leave residues in drinking water, especially since it is not taken up by the roots of plants and plants cannot metabolise it. Glyphosate is not thought to be harmful to human beings under usual conditions, however, higher nonstandard levels of intoxication can cause erosion of the gastrointestinal tract, but evidence of this is based on intentional intoxication.


Heavy metals

Heavy metals are normally present in drinking water in small amounts and support everyday body functioning; however, excess exposure to heavy metals is a hazard for health. Heavy metals enter groundwater geologically, as a consequence of agricultural activities and through industrial wastewater. Effect on the human body varies depending on the metal variety and concentration. It may include allergic dermatitis, renal arterial hypertension, liver and kidney diseases, bone and brain diseases, delays in the physical and mental development of infants, and more.



Heptachlor is a white crystalline solid that is used to control insect pests and it is applied to soil, seeds and foliage. Acute exposure to Heptachlor can cause nervous system effects such as irritability, salivation, laboured respiration and more, however, it is not thought to be carcinogenic.



Herbicides are a term used to describe a range of chemicals that are used to treat and control weeds. Herbicides used a variety of active ingredients, some of which are more likely than others to transit to the groundwater through the soil after an application. Level of herbicide contamination in water can vary from month to month and from season to season. All herbicides have some toxicity to them, levels of which vary between products; the effect of them on human health would vary depending on the consumed chemical and dosage.




Iodine is a non-metallic element and naturally occurs as iodide in water, but becomes iodine once oxidised by water treatment processes. While higher dosages of iodine can cause symptoms such as irritation to the lungs, gastrointestinal tract and eyes, angio-oedema, iodism, pulmonary oedema and other illnesses or death, the chronic consumption of normal levels of iodinated drinking water are not thought to be harmful to human beings.



Iron is the fourth most abundant mineral that is found in the Earth’s crust, soil and rocks. Iron is beneficial to the human body, it gives the haemoglobin of blood its red colour and allows blood to carry oxygen. Since Iron is needed to transport oxygen in the blood, it does not usually present a health problem, however, some pathogenic (harmful) organisms require iron to grow, and the presence of iron particles makes the elimination of such organisms more difficult.

Large Bacteria

Whilst the majority of bacteria that is transmitted by water affects the gastrointestinal tract; there is a number of waterborne pathogens which are transmitted during bathing via inhalation and direct contact with water. The latter pathogens cause infections of the respiratory tract, brain and skin lesions.



Lead is a poisonous metal, the consumption of lead can cause long-term health and behavioural problems. There is no safe level of lead, it can damage the brain, kidneys and nervous system.



Lindane is an insecticide, which is used on a variety of crops and greenhouse vegetables, and in forestry for seed treatment. In addition to this, lindane is used as a therapeutic pesticide, for example as a scabies treatment in humans and animals. Lindane can physically enter the water from direct application for the control of mosquitos and from use in agriculture and forestry. The main route of exposure to humans is through the consumption of food. Both short-term and long-term studies have concluded that lindane was toxic to the kidney and liver regardless of route of exposure.



Mercury is an element that naturally occurs in rocks, soil, water, air and living beings. Short-term exposure can cause skin rashes, diarrhoea and respiratory distress. Long-term exposure can cause muscle tremors, irritability, personality changes and rashes.  Mercury can also cause nerve damage and may cause a loss of sensitivity in the hands and feet, difficulty walking or slurred speech. Mercury consumption can also cause paralysis or death in rare cases.



Nitrate ions occur naturally as part of the nitrogen cycle and are used as inorganic fertilisers. Nitrates can also be used in the production of explosives and glass making. Nitrogen can infiltrate both surface and groundwater due to agricultural use. When high levels of nitrates have reduced to nitrites, the nitrites may cause illnesses such as methaemoglobinaemia, congenital malformations, goitre, cancer and more.



Oxamyl is a pesticide used to control insects and mites on a variety of crops, as well as on tobacco and in plant nurseries. Short-term exposure to the chemical will lead to tremors, salivation and tearing due to interference with nerve function. Oxamyl will decrease body weight if exposure id long term. It is recommended by the US Environmental Protection Agency to use granular activated charcoal to remove oxamyl from your drinking water.



Pentachlorophenol is a synthetically manufactured chemical, which takes the form of a clear crystal. Pentachlorophenol is used as a pesticide and wood preservative. Currently, sale and use of the chemical is restricted and it is unavailable to the general public. Exposure to pentachlorophenol causes issues with liver, kidneys, blood, lungs, nervous system, immune system, and gastrointestinal tract.



Pesticides is a term used to describe a range of chemicals that are used to treat pests like weeds and insects. These chemicals include herbicides, disinfectants, fungicides, insecticides, natural and biological pesticides, repellents, and rodenticides. Level of pesticide contamination in water can vary from month to month and from season to season. All pesticides have some toxicity to them, levels of which vary between products; the effect of them on human health would vary depending on the consumed chemical and dosage. Charcoal filters and reverse-osmosis treatments can be used to remove or minimise pesticides in drinking water at home.



Petrochemicals is a term for a variety of compounds that can be derived from the petroleum refinery products. One is the most common ones are xylene, styrene, toluene, parabens and bisphenol A. A lot of these are known neurotoxins and have an adverse effect on human health; many of them accumulate in tissues/organs and cause brain, nerve and liver damage, as well as birth defects, cancer, asthma and hormonal disorders. Long term exposure leads to skin irritation, ulcers and allergic dermatitis. Please refer to individual contaminants to learn more about them individually.



Pharmaceuticals is a term for chemicals (both natural and synthetic) that exist in a variety of drugs, for example, prescription and over-the-counter drug as well as veterinary medicine. Pharmaceuticals penetrate surface water and drinking water through raw sewage and wastewater discharges. Consumption of water with a low concentration of pharmaceuticals is extremely unlikely to cause any significant adverse health impacts on humans. Some advanced water treatment processes target specific pharmaceuticals compounds and can achieve high removal rates (above 99%), namely, ozonation, advanced oxidation, activated carbon and membranes (e.g. nanofiltration, reverse osmosis).



Phenol is obtained through a distillation of coal and mainly used in the production of plastics, pharmaceutical products, as a general disinfectant and in consumer products such as mouthwashes, gargles and throat sprays. Phenol gets into the water following release from the manufacture, use and disposal of phenol-containing products, and by travelling through the soil. Consumption of ethanol can lead to gastrointestinal irritation, cardiac dysrhythmias and cardiovascular shock, respiratory distress, renal failure, dark urine, a variety of neurobiological effects, as well as coma and death.



Plumb consists of lead and other heavy metals. It gets in the water through corrosion of household plumbing. Lead is highly toxic and may cause delays in physical and mental development in infants, as well as a variety of kidney problems and blood pressure issues in adults.

  • [0] E. Vetrimurugan, K. Brindha, L. Elango, Osman Muzi Ndwandwe. (March 2016). [Accessed May 2019].


Pollen is a fine powder of yellowish grain-like pores, originating from the fertilizing element of flowering plants. Pollen absorb heavy metals from the air and can have an indirect effect on human health when consumed.


Polychlorinated Biphenyls (PCBs)

Polychlorinated Biphenyls (PCBs) are synthetic chemicals and do not naturally appear in the world. 130 variations of PCBs were identified in commercial use as dielectric and heat exchange fuel. Humans are exposed to PCBs via air, drinking water and food. Toxicological effects include progressive weight loss, effects on liver, skin, immune system, the gastrointestinal tract, the reprodactive system, oedemas, thyroid gland disturbances, as well as induction of cancer and, in acute cases, death.


Protozoan Parasites

Protozoa pathogens are the most common underlying causes of infections and diseases in humans and animals; they are also responsible for “emerging diseases”, such as cryptosporidiosis. The pathogens produce disinfection-resistant cysts, oocysts or eggs, which are transmitted by water and can be challenging to filter out. Effects on the human health and organs involved will vary depending on the pathogen.


Radio Nuclides


Radium exists in several forms of isotopes, which naturally occur during the breakdown process of uranium and thorium. It is a radioactive metal, which is silvery-white in colour and can be found at very low levels in most rocks and soil. Radium is released into the atmosphere via coal combustion, which can later also contaminate soil as a fallout of coal fly ash; the metal contaminates water as the result of leaching of uranium mine tailings. Long term inhalation of the particles leads to acute leukopenia. Long-term ingestion of radium leads to bone sarcomas, carcinomas of the perinasal sinuses and mastoid air cells, deterioration of skeletal tissue and death.


Radon 222

Radon 222 is the most common isotope of radon, which is a noble gas and occurs naturally as a part of radioactive decay of radium. Humans are exposed to the radon mainly via radon-contaminated soil; however, exposure can also occur from air and drinking water. Induction of lung cancer is the only effect that radon exposure has on human health.







Silver occurs naturally in nature and is a by-product of the retrieval of copper, lead, zinc, and gold ores. The metal is commonly used to make jewellery, silverware, electronic equipment, and dental fillings. Silver is known for its antibacterial qualities and is often used to disinfect drinking water and water in swimming pools. A number of products that help to quit smoking, such as lozenges and chewing gum, were noted to contain silver. Everyone is exposed to a very low amount of silver daily through food, water, air and wearing jewellery. Exposure to a large amount of silver can cause respiratory irritation, abdominal pain, skin discolouration and burns, and weight loss.




Styrene is an easily evaporating colourless synthetic chemical, which is often presented in a form of liquid with a sweet aroma. The chemical is known under other names: vinylbenzene, ethenylbenzene, cinnamene, or phenylethylene. Traces of styrene are found in food, however, the majority of styrene is generated commercially to produce rubber, plastic, insulation, fibreglass, pipes, automobile parts, food containers, and carpet backing. The production and use of chemical cause water, soil and air pollution. It must be noted that styrene would rapidly reduce in soil and evaporate from water into the atmosphere, which makes air the main route of exposure. Styrene is found in combustion products like automobile exhaust and cigarettes. Exposure to styrene would greatly affect the neural system: partial hearing and colour vision loss, vestibular effects, neurotoxicity symptoms (“feeling drunk” and fatigue), reaction time delays, attention and memory impairment. Last but not least, styrene has been classified as a human carcinogen.




Toluene is a clear liquid with a unique odour. It is present naturally in crude oil and the tolu tree. The colourless liquid is also a by-product of various fuels (eg gasoline) that are processed from crude oil and making coke from coal. Toluene is a solvent and is often used in paint and paint thinners, as well as in lacquers, adhesives, rubber and other processes. Toluene is rarely found in food or water and the main route of exposure to the contaminant is through breathing in car fumes and cigarette smoke, and through using various paints and polishes. Minor exposure to toluene can affect the nervous system: weakness and fatigue, memory loss and confusion, nausea and loss of appetite are common symptoms of low exposure. Some occupations can lead to long-term exposure to toluene and would manifest itself in partial hearing and color vision loss.




Trihalomethane is a common disinfection byproduct, which occurs when disinfectants interact with naturally present organic matter in water during public water systems disinfection processes. Prolonged consumption can lead to bladder cancer and developmental effects.



Turbidity is a term used to describe the cloudiness of water. The major source of turbidity is suspended fine particles, such as soils, clays and other natural organic matter, which are harmless in their nature. Nevertheless, turbidity may also be caused by the presence of hazardous chemical and microbial contaminants, which will have a serious effect on human health.



Uranium is a common radioactive substance, which occurs naturally as a mineral in air, water, soil and rocks. There are three varieties of naturally occurring uranium isotopes: U-234/234U, U-235/235U and U-238/238U. All three isotopes present the same chemical, however, the radioactive effect varies among them. Primary exposure to uranium happens through consumption of food and drinking water, in particularly root crops and unwashed potatoes. People living next to uranium mines, as uranium processing and manufacturing facilities are more likely to have a higher rate of exposure to the substance. In terms of effects on human health, uranium causes kidneys damage.



Majority of viruses that are transmitted by water belong to a group known as enteric viruses, which are associated with infections of the gastrointestinal tract. In addition to the enteric group of viruses, water can also facilitate the transmission of other types of viruses. As a result, symptoms, routes of transmissions and sites of infection will change with types of stains.



Xylene is a colourless and highly-flammable liquid, which occurs naturally in petroleum and is produced from it. It is used commercially as a solvent, a cleaning agent, and a paint thinner and in the printing, rubber, and leather industries. Exposure to xylene occurs primarily from car exhausts via air; however, the liquid can enter soil and water at hazardous waste disposal sites and through spills. Although xylene is not commonly found in the drinking water, short-term exposure to high levels of xylene results in skin and ENT irritation, impaired function of the lungs, reduced response to a visual stimulus, memory issues, stomach discomfort and possible changes in the liver and
kidneys. Effect on the nervous system is manifested through headaches, lack of muscle coordination, dizziness, confusion, and changes in one’s sense of balance.



Zinc is a common metal, which is present in the air, water, soil and all food. Commercially the metal is often used for coatings that prevent the appearance of rust, in dry cell batteries, and as alloys. The major route of exposure to zinc is through consumption of food and drinking water. High consumption of zinc leads to gastrointestinal irritation with vomiting, diarrhoea and abdominal cramps. Long-term exposure leads to copper deficiency.