gen, bleach, salts, pesticides, metals, toxins produced by bacteria, and human or animal drugs are all examples of chemical contaminants. Microbes or microbiological contaminants are also known as biological contaminants.
Environmental Protection Agency has classified contaminants in water into 4 categories and for better regulation, EPA invites the public to nominate contaminants in the Contaminants Candidate List.

What are water contaminants? – Definition:
Water contaminants are materials that may be found in water that can pose a health risk if ingested. Common water contaminants include bacteria, viruses, fungi, and protozoans. Water may also contain chemical contaminants, such as pesticides, metals, and toxins produced by industrial processes.
Every day, millions of people around the world rely on public and private water sources. Little do many know, there are many common contaminants in water, even the water that comes directly from treatment plants. Even though municipal water treatment plants remove particulates to clean the water, most of these plants add chlorination chemicals to kill bacteria and viruses. Not only are these chemicals harmful to these micro-organisms (microbes), but they are also harmful to us. Neither the chemicals, nor the dead bacteria are removed from the water before it reaches us, however.
Furthermore, treatment plants do not remove the traces of industrial chemicals and pharmaceuticals that are increasingly finding their way into our water ways, and into our bodies through our drinking water.
This is putting everyone at risk for sickness and disease. Even though it’s not mentioned in the mainstream media very often, if at all, cancer rates are at epidemic levels today, and they are increasing. Below are two charts of common chemical contaminants in water. They are increasingly finding their way into our water supplies. Fortunately, the charts also indicate the best filtration method that is most successful in eliminating the chemicals from our drinking water.
CONTAMINANTS REMOVED BY CARBON FILTRATION
Chemicals | organic Contaminants |
Acetaldehyde | 2,4,5-TP |
Acetic Acid | 2,4-D |
Acetone | Acrylamide |
Alcohols | Adipates (diethylhexyl) |
Amines | Alachlor |
Amyl Acetate | Aldicarb |
Amyl Alcohol | Aldicarb Sulfone |
Antifreeze | Aldicarb Sulfoxide |
Benzene (“fracking” carcinogen) | Atrazine (agricultural herbicide) |
Bleach | Benz(a)anthracene (PAH) |
Butyl Alcohol | Benzene (“fracking” carcinogen) |
Butyl Acetate | Benzo(a)pyrene (PAH) |
Calcium Hypochlorite | Benzo(b)fluoranthene (PAH) |
Chloral | Benzo(k) fluoranthene (PAH) |
Chloamine | Bromodichloromethane |
Chloroform | Bromoform |
Chlorine | Butyl benzyl phthalate (PAE) |
Chlorobenzene | Carbofuran |
Chlorophenol | Carbon Tetrachloride Chlordane |
Chlorophyll | Chloroform |
Citric Acid | Chrysene (PAH) |
Cresol | Dalapon |
Defoilants (plant growth inhibitors) | Dibenz(a,h) anthracene (PAH) |
Detergents | Dibromochloromethane |
Diesel Fuel | Dibromochloropropane (DBCP) |
Dyes | Dichlorobenzene (o-,m-) |
Ethyl Acetate | Dichlorobenzene (para-) |
Ethyl Acrylate | Dichloroethane (1,2-) |
Ethyl Alcohol | Dichloroethylene (1,1-) |
Ethyl Amine | Dichloroethylene (cis-1,2-) |
Ethyl Chlorine | Dichloroethylene (trans-1,2-) |
Ethyl Ether | Dichloromethane (methylene chloride) |
Gasoline | Dichloropropane (1,2-) |
Glycols (“fracking” toxins) | Diethylhexyl phthalate (PAE) |
Herbicides | Dinoseb |
Hydrogen Peroxide | Diquat |
Hydrogen Selenide | Endothall |
Hydrogen Sulfide | Endrin |
Hypochlorous Acid | Epichlorohydrin |
Insecticides | Ethylbenzene |
Iodine | Ethylene dibromide (EDB) |
Isopropyl Acetate | Glyphosate (Round Up herbicide) |
Isopropyl Alcohol | Heptachlor |
Ketones | Heptachlor epoxide |
Lactic Acid | Hexachlorobeneze |
Mercaptans | Hexachlorocyclopentadiene |
Methyl Acetate | Indeno (1,2,3-c,d) pyrene (PAH) |
Methyl Alcohol | Lindane |
Methyl Bromide | Methoxychlor |
Methyl Chloride | Monochlorobenzene |
Methyl Ethyl Ketone | Oxamyl (vydate) |
Naphtha | Pentachlorophenol |
Nitric Acid | Picloram |
Nitrobenzene | Polychlorinated byphenyls (PCBS) |
Nitrotoluene | Simazine |
Odors (general) | Styrene |
Oil Dissolved | Tetrachloroethylene |
Organic Acids | Toluene |
Organic Esters | Toxaphene |
Organic Salts | Trichlorobenzne (1,2,4) |
Oxalic Acids | Trichloroethane (1,1,1-) |
PCB?s | Trichloroethylene |
Perchlorate (used in rocket fuels) | Trichloroethylene (1,1,2-) |
Pesticides | Trihalomethanes (THMs) |
Phenol | Vinyl Chloride |
Plastic Taste | Xylene (total) |
Propioic Acids | 2,3,7,8-TCDD (Dioxin) |
Propionaldehyde | |
Propyl Acetate | |
Propyl Acid | |
Propyl Chloride | |
Rubber Hose Taste | |
Soap | |
Sodium Hydrochorite | |
Solvents | |
Sulphonated Oils | |
Tannins | |
Tar Emulsion | |
Tartaric Acid | |
Taste (DI Water) | |
Taste (From Organics) | |
THM?s | |
Toluene | |
Toluidine | |
Trchlorethylene | |
Turpintine | |
Vinegar | |
Xanthophyll | |
Xylene |
CONTAMINANTS REMOVED BY REVERSE OSMOSIS
CONTAMINANT | AVERAGE INFLUENT (INCOMING) CONCENTRATION (MG/L) | AVERAGE EFFLUENT (OUTGOING) CONCENTRATION (MG/L) | AVERAGE PERCENT REDUCTION |
---|---|---|---|
Arsenic | 0.28 | 0.0035 | 98.7 |
Barium | 10.2 | 0.207 | 97.9 |
Cadmium | 0.036 | 0.0005 | 98.6 |
Chromium (Hexavalent) | 0.15 | 0.013 | 91.3 |
Chromium (Trivalent) | 0.17 | 0.01 | 94.1 |
Copper | 3.1 | 0.03 | 99 |
Cysts | 149357 #/ml | 5 #/ml | 99.99 |
Turbidity | 10.2 | 0.26 | 97.5 |
Fluoride | 8 | 0.5 | 93.9 |
Lead | 0.15 | 0.002 | 98.6 |
Radium 226/228 | 25 pCi/L | 5 pCi/L | 80 |
Selenium | 0.1 | 0.008 | 92 |
Reverse Osmosis Systems are not all the same, and don’t have the same performance level. Some only filter out a few contaminants, whereas others do a much better job at eliminating most contaminants in the water.
Even the best reverse osmosis systems won’t always filter out everything 100%. There are several factors for this, but the best way to maximize your systems performance, is to change the filters out for new ones, at recommended intervals.
This is why it’s recommend to change your water filters frequently, and definitely no later than a filters recommended service period.
First List – Contaminants Candidates List(CCL 1)
Under Schedule 1 set up by FDA on Safe water drinking act, 1974 and amended in 2001 the following contaminants were included in CCL 1.
- Acanthamoeba
- Aldrin
- Dieldrin
- Hexachlorobutadiene
- Manganese
- Metribuzin
- Naphthalene
- Sodium
- Sulfate
Agency for Toxic Substances and Disease Registry(ASTDR) has prepared a Hazardous Substances Data Bank(HSDB) on these 54 contaminants which may provide additional information.
Second List – Contaminants Candidates List (CCL 2)
EPA published the second Drinking Water Contaminant Candidate List (CCL) on February 23, 2005. Our goal is to improve and expand the underlying CCL listing process to be used for future CCLs.
- Adenoviruses
- Aeromonas hydrophila
- Caliciviruses
- Coxsackieviruses
- Cyanobacteria (blue-green algae), other freshwater algae, and their toxins
- Echoviruses
- Helicobacter pylori
- Microsporidia (Enterocytozoon & Septata)
- Mycobacterium avium intracellulare (MAC)
How do water contaminants get into my water?
Biological contaminants, such as bacteria and viruses, can enter water through sewage or animal waste. If these sources are not properly treated, they can contaminate groundwater or surface water.
Chemical contaminants may come from a variety of sources, including agricultural runoff, urban stormwater runoff, wastewater discharge, and industrial discharges. Metal contamination may also occur naturally in some water sources.
What are the health effects of water contamination?
The health effects of water contamination depend on the type and concentration of the contaminant, as well as the length of time you are exposed to it. Some contaminants, such as bacteria and viruses, can cause infections or gastrointestinal illness. Others, such as lead and mercury, can damage the nervous system. Still others, such as certain chemicals used in industrial processes, can increase your risk of cancer.
In this guide, I have compiled a list of contaminants in water that are commonly removed by reverse osmosis systems, as well as the methods used to remove them.
How can I protect myself from water contaminants?
The best way to protect yourself from water contaminants is to drink only treated or bottled water. If you suspect that your tap water is contaminated, you can have it tested by a certified laboratory. You can also take steps to protect yourself from contaminants in surface water, such as avoiding swimming in water that may be contaminated with sewage or animal waste.
What is being done to reduce water contamination?
Water treatment facilities are required to meet strict standards for the removal of contaminants. In addition, state and federal laws regulate the discharge of pollutants from factories, power plants, and other industries.
What can I do to reduce water contamination?
You can help reduce water contamination by disposing of hazardous materials, such as oil and chemicals, properly. You can also help keep contaminants out of surface water by being careful not to pollute when you are outdoors. For example, you should dispose of trash properly and avoid using fertilizers and pesticides on your lawn.
List of water contaminants and harmful effects to humans:
Nitrates:
These are inorganic compounds that are found in nature, specifically as a by-product of decomposing organic matter. They can enter water through agricultural runoff or sewage discharge. Ingesting high levels of nitrates can cause “blue baby syndrome,” which is a serious condition that can lead to death.
Chlorine: This is a chemical that is used to disinfect water. It is added to public water supplies to kill harmful bacteria. However, ingesting high levels of chlorine can lead to stomach upset and diarrhea.
Lead: This is a metal that can be found in nature or may be released into the environment from industrial sources. It can enter water through leaching from lead pipes or from lead-based paint. Ingesting high levels of lead can damage the nervous system and cause learning disabilities.
Mercury: This is a metal that can be found in nature or may be released into the environment from industrial sources. It can enter water through leaching from mercury-containing products, such as thermometers and fluorescent light bulbs. Ingesting high levels of mercury can damage the nervous system.
Arsenic: This is a chemical that can be found in nature or may be released into the environment from industrial sources. It can enter water through leaching from arsenic-containing products, such as pressure-treated wood and pesticides. Ingesting high levels of arsenic can increase your risk of cancer.
Selenium: This is a chemical that can be found in nature. It can enter water through leaching from rocks and soil. Ingesting high levels of selenium can cause gastrointestinal upset.
Fluoride: This is a chemical that is added to public water supplies to help prevent tooth decay. Ingesting high levels of fluoride can cause bone damage.
Chromium: This is a metal that can be found in nature or may be released into the environment from industrial sources. It can enter water through leaching from chromium-containing products, such as steel and leather. Ingesting high levels of chromium can increase your risk of cancer.
PCBs: These are man-made chemicals that were used in a variety of products, such as coolants and lubricants, until they were banned in the 1970s. They can enter water through leaching from landfill sites. Ingesting high levels of PCBs can cause liver damage.
Pesticides: These are chemicals that are used to kill insects, weeds, and other pests. They can enter water through agricultural runoff or residential use. Ingesting high levels of pesticides can cause nervous system damage.
Herbicides: These are chemicals that are used to kill plants. They can enter water through agricultural runoff or residential use. Ingesting high levels of herbicides can cause liver damage.
Disinfection by-products: These are chemicals that are formed when water is treated with chlorine or other disinfectants. They can enter water through leaching from pipes or treatment plants. Ingesting high levels of disinfection by-products can increase your risk of cancer.
Microorganisms: These are tiny organisms, such as bacteria, viruses, and protozoans, that can cause disease. They can enter water through sewage discharge or agricultural runoff. Ingesting high levels of microorganisms can cause gastrointestinal illness.
Types of Drinking Water Contaminants
Under the Safe Drinking Water Act, “contaminant” is defined as “any physical, chemical, biological, or radiological substance or thing in water.” As a result, the law characterizes “contaminant” extremely broadly as anything other than water molecules. Some drinking water contaminants may be detrimental at particular levels. Contaminants do not always indicate that the water is dangerous to drink.
Physical Contaminants:
Contaminants that impact the physical appearance or other physical properties of water are referred to as physical contaminants. Sediment and organic material suspended in lakes, rivers, and streams from soil erosion are examples of physical contaminants.
Chemical contaminants:
Chemical contaminants in water are elements or compounds. These contaminants might be naturally occurring or manufactured by humans. Nitrogen, bleach, salts, pesticides, metals, poisons produced by bacteria, and medicines taken by people or animals are all examples of chemical pollutants.
Biological contaminants:
Biological contaminants in water can be microscopic organisms such as bacteria, viruses, protozoa, and parasites. These contaminants are capable of causing disease in humans and animals. Human sewage, animal waste, and agricultural runoff can all introduce biological pollutants into the environment.
Radiological contaminants:
Radiological contaminants are radioactive elements or compounds. They can be of natural or man-made origin. Radon, a gas that can be found in rocks and soil, is an example of a naturally occurring radiological contaminant. Radioactive waste from nuclear power plants and other human activities can also introduce radiological contaminants into the environment.
Regulations to Prevent Water Contamination:
EPA has made significant progress since the initial Safe Water Act, 1974 with several amendments to the ACT aimed at further protecting our water resources from contaminants.
The most recent and comprehensive amendment to the Act was the 1996 SDWA Amendments. These Amendments directed EPA to set new National Primary Drinking Water Regulations (NPDWRs or primary standards) for 96 previously unregulated contaminants, including Cryptosporidium, a protozoan that can cause gastrointestinal illness. The Amendments also required EPA to review all existing drinking water regulations and revise them, if appropriate, to ensure that they provide adequate public health protection.
In addition to the 1996 Amendments, EPA has subsequently promulgated new or revised NPDWRs for several other contaminants, including arsenic, radionuclides, and disinfection byproducts. The Agency is also in the process of finalizing new or revised regulations for lead and copper, microbial contaminants, and other chemicals.
List of Contaminants in Water:
The following are lists of common drinking water contaminants and their possible health effects. These lists are not all-inclusive.
Inorganic Contaminants
Arsenic:
Arsenic is a naturally occurring element in the environment that can be found in water, air, food, and soil. It can also be released into the environment from certain human activities, such as mining, coal-burning power plants, and using certain pesticides. EPA has set the maximum contaminant level goal (MCLG) for arsenic at 0 ppb because arsenic is a known human carcinogen.
Chromium:
Chromium is a naturally occurring element found in rocks, animals, plants, and soil. It can also be released into the environment from industrial activities. EPA has set an MCLG for chromium of 0 ppb because it is a known human carcinogen.
Copper: Copper is a naturally occurring element found in the environment. It is an essential nutrient for human health, but can be harmful at high concentrations. EPA has set an MCLG for copper of 1.3 ppm because it can cause gastrointestinal distress.
Fluoride:
Fluoride is a mineral that occurs naturally in all water sources, even the oceans. It is also added to public water supplies to help prevent tooth decay. The maximum contaminant level goal (MCLG) for fluoride is 4 mg/L or 4 ppm because it can cause dental fluorosis, a condition that results in the discoloration and weakening of teeth.
Lead:
Lead is a metal that can be found in the environment naturally or can result from human activities. It can be released into air, water, and soil from industrial emissions and from the burning of fossil fuels. Lead can also enter drinking water through lead pipes and solder in home plumbing. The MCLG for lead is 0 ppb because it can cause serious health problems, including brain damage, kidney damage, and high blood pressure.
Mercury:
Mercury is a naturally occurring element that can be found in air, water, and soil. It can also be released into the environment from burning coal and other fossil fuels. Methylmercury, a type of mercury that can build up in fish, is the main concern for human health. The MCLG for mercury is 0.002 mg/L or 2 ppb because it can cause neurological damage.
Nitrate and Nitrite:
Nitrate and nitrites are compounds that occurs naturally in the environment and can also come from human activities, such as farming and sewage treatment. It can enter drinking water through runoff from fertilizer use and from septic tanks and sewage treatment plants. The MCLG for nitrate is 10 ppm because it can cause methemoglobinemia, a blood disorder that can be fatal in infants.
The MCLG for nitrite is 1 ppm because it can cause methemoglobinemia, a blood disorder that can be fatal in infants.
Radium:
Radium is a radioactive element that occurs naturally in the environment. It can be found in rocks, soil, water, and air. Radium can enter drinking water through leaching from natural deposits in the earth or from discharge from phosphate fertilizer plants and uranium mines. EPA has set an MCLG for radium of 0 pCi/L (picocuries per liter) because it is a known human carcinogen.
Sulfate:
Sulfate is a compound that occurs naturally in water, air, and soil. It can also come from industrial activities, such as mining and manufacturing. Sulfate can enter drinking water through runoff from agricultural land and from sewage effluent. The MCLG for sulfate is 250 mg/L or 250 ppm because it can cause gastrointestinal distress.
How contamination in water is determined:
Total Dissolved Solids (TDS):
Total dissolved solids (TDS) is a measure of the amount of organic and inorganic matter in water. TDS can come from a variety of sources, including runoff from agricultural land, stormwater discharge, sewage effluent, and industrial wastewater. The MCLG for TDS is 500 mg/L or 500 ppm because it can cause a variety of health problems, including gastrointestinal distress and kidney damage.
Turbidity:
Turbidity is a measure of the amount of suspended particles in water. These particles can come from a variety of sources, including runoff from agricultural land, stormwater discharge, sewage effluent, and industrial wastewater. The MCLG for turbidity is 5 NTU (nephelometric turbidity units) because it can interfere with the disinfection of drinking water and provide a haven for bacteria.
pH:
pH is a measure of the acidity or alkalinity of water. The pH of natural waters can range from acidic to basic, but the vast majority of waters are neutral. The MCLG for pH is 6.5-8.5 because water that is too acidic or too basic can cause a variety of health problems, including gastrointestinal distress and skin irritation.
Color:
Color is a measure of the amount of dissolved minerals in water. These minerals can come from a variety of sources, including rocks and soil. The MCLG for color is 15 PCU (platinum-cobalt units) because it can cause aesthetic problems, such as staining of laundry and fixtures.
Odor:
Odor is a measure of the amount of dissolved organic matter in water. This organic matter can come from a variety of sources, including decaying plants and animals. The MCLG for odor is 0 because it can cause aesthetic problems, such as taste and smell.
Taste:
Taste is a measure of the amount of dissolved minerals in water. These minerals can come from a variety of sources, including rocks and soil. The MCLG for taste is 0 because it can cause aesthetic problems, such as taste and smell.
How reverse osmosis removes water contaminants:
Reverse osmosis systems can remove physical, chemical, biological, and radiological contaminants from water by trapping them on the filter membrane.
The filter membrane is a thin, semipermeable sheet that only allows water molecules to pass through. All other contaminants are rejected and remain on the side of the membrane where they were initially located.
Reverse osmosis systems are designed to remove a wide range of contaminants, including dissolved solids, bacteria, viruses, protozoa, and metals.
Some pros and cons:
Reverse osmosis systems are effective at removing contaminants from water, but they have a few drawbacks. First, they can be expensive to purchase and operate. Second, reverse osmosis systems require frequent maintenance to ensure that they are operating properly. Third, the filtered water produced by reverse osmosis systems can have a slightly salty taste. Finally, reverse osmosis systems can waste a lot of water because they reject most of the water that they come into contact with.
Despite these drawbacks, reverse osmosis systems are still one of the most effective ways to remove contaminants from drinking water. If you are concerned about the quality of your drinking water, you may want to consider installing a reverse osmosis system in your home.
Main Water contaminants and their sources:
1. Arsenic: Arsenic is a naturally occurring element that can be found in rocks, soil, and water. It can also be released into the environment from industrial activities such as mining and manufacturing. Arsenic is known to cause cancer in humans and is considered a serious health hazard.
2. Bacteria: Bacteria are single-celled organisms that can be found in water, soil, and air. Some types of bacteria are beneficial to humans, while others can cause disease. Bacteria can enter the environment through sewage, animal waste, and agricultural runoff.
3. Chlorine: Chlorine is a chemical element that is used to disinfect water. It is also used in swimming pools and hot tubs to kill bacteria and other microbes. Chlorine can enter the environment from industrial facilities, sewage treatment plants, and agricultural operations.
4. Lead: Lead is a heavy metal that can be found in rocks, soil, and water. It can also be released into the environment from industrial activities such as mining, smelting, and manufacturing. Lead is known to cause health problems in humans, including brain damage and kidney disease.
5. Mercury: Mercury is a naturally occurring element that can be found in rocks, soil, and water. It can also be released into the environment from industrial activities such as coal-burning power plants and waste incineration. Mercury is known to cause health problems in humans, including brain damage and kidney disease.
Common water contaminants examples:
Some of the main contaminants can come from nature or Humans. Chemical pollutants include things like bleach, nitrogen, pesticides, and metals. impurities produced by bacteria are also examples of water contamination. Biological is another term for organisms in water that can make people sick–these are also called microbes or microscopic biologicals.
Microorganisms, nitrates, and arsenic are the most frequent drinking water contaminants. Water quality monitoring has improved in the last five years. Bacteria, viruses, and protozoa (such as Giardia lamblia and Cryptosporidium) are pathogens that may cause widespread and severe illnesses if ingested via contaminated water.
What are some of the major water pollutants today?
Among the many water pollutants are bacteria, viruses, parasites, fertilisers, pesticides, pharmaceutical products, nitrates, phosphates, plastics, faecal waste and even radioactive substances. The types and levels of water pollutants vary depending on the geographical location, method of sewage disposal, agricultural and industrial activity in the area.
In the US, some Zip codes have been shown to have water with unsafe levels of lead. Lead is a heavy metal that can be found in rocks, soil and water, as well as being released into the environment from industrial activities such as mining, smelting and manufacturing. It can also enter the water supply through old plumbing fixtures and fittings. Lead is known to cause health problems in humans, including brain damage and kidney disease.
In 2015, the state of California issued a warning to residents not to drink or cook with tap water in certain areas due to high levels of chromium-6. Chromium-6 is a chemical element that is used in industrial processes such as metal plating, leather tanning and wood preservation. It can also enter the environment from coal-burning power plants and waste incineration. Chromium-6 is known to cause cancer in humans and is considered a serious health hazard.
It is important to be aware of the potential contaminants in your water supply, whether it comes from a private well or a public water system. If you are concerned about the quality of your water, you can contact your local water utility or county health department for more information. You can also have your water tested by a certified laboratory.
How can water be polluted?
Water can become polluted by a variety of sources, including sewage effluent, animal waste, agricultural runoff, industrial discharge, and oil spills. Water pollution can also occur naturally when water is contaminated with minerals or other substances.
How does water pollution affect humans?
Water pollution can cause a variety of health problems in humans, including gastrointestinal illness, skin infections, and respiratory disease. Water pollution can also lead to the spread of disease-causing microorganisms. In addition, water pollution can damage the environment and adversely affect the quality of life.
What are some common water contaminants?
Common water contaminants include bacteria, viruses, parasites, fertilizers, pesticides, pharmaceuticals, nitrates, phosphates, plastics, and faecal waste. Water contamination can also occur naturally when water is contaminated with minerals or other substances.
How can I tell if my water is safe to drink?
If you are concerned about the quality of your water, you can contact your local water utility or county health department for more information. You can also have your water tested by a certified laboratory.
How Contaminants Contribute to RO System Performance
- Contaminant level of the incoming water supply.
- Whether or not a sediment filter is used, if incoming water has large particles, such as from a well.
- Type of prefiltration (granulated-carbon, carbon-block, activated or not).
- Size of pores in the RO membrane (the smaller, the better).
- How well the system is maintained (how often the filters are changed).