Water WELLography First Edition

Elements of Water

The elements of water described below include microorganisms, disinfectants and their byproducts, inorganic, organic and petroleum-based contaminants, pesticides and herbicides, and taste properties of potable water.

As of 2017, some 85,000 chemicals have been included in the inventory laid out in the U.S. Toxic Substances Control Act (TSCA), although not all are currently in commerce, with applications and uses ranging from flavoring and adding scents to plastics and flame retardation.³⁷ This act, implemented in 1976, provides the EPA with authority to regulate toxic substances including, polycholorinated biphenyls (PCBs), asbestos, lead, mercury, formaldehyde and certain hexavalent chromium compounds.³⁸ These chemicals can enter the water, air, and food supplies in a variety of ways, both intentionally and unintentionally. In addition, the water supply is vulnerable to biological contaminants such as bacteria, viruses, and protozoa. Biological contaminants can also be introduced into the water supply in a variety of ways from personal care products, industry, groundwater pollution, biological infestation, and other sources, while others come from the breakdown of disinfectants intentionally introduced through water treatment.³⁹ Once in the water supply, sufficiently high concentrations of these pollutants may pose severe risks to human health in the form of microbial infections, cancer, and birth defects among others.³⁹

Microorganisms Present in Water Supplies

According to CDC from 2009 – 2010, 33 drinking water-associated outbreaks were reported, resulting in 1,040 cases of illness, 85 hospitalizations, and nine deaths.⁴⁰ In addition, based on the Global Infectious Disease and Epidemiology Network (GIDEON) database, areas across the world are at a higher risk of experiencing infectious disease epidemics due to water-associated outbreaks.⁴¹ While Brazil, northwest Africa, central Africa, and southwest China are at a higher risk for water-based diseases like schistosomiasis, areas in central Africa and North India have a higher risk of experiencing water-related diseases like malaria and dengue fever. In addition, western Europeans have an increased risk of encountering water-dispersed diseases.⁴¹

Disease-causing organisms, microorganisms or microbes are often referred to as pathogens. Waterborne diseases are caused by contact with or ingestion of pathogenic microorganisms. Pathogens may include various types of bacteria, protozoa, parasites, and other microscopic organisms.

1. Total Coliforms

Bacterial coliforms are a broad class of rod-shaped, non-sporulating bacteria that can come from multiple sources in the environment and fail to form new spores, which are reproductive cells.⁴² Their presence suggests that fecal pathogens, including the more-resistant non-coliform pathogens, might also be inhabiting the water source. Therefore, coliforms are often used as an indicator of contamination given that exposure to water containing coliforms could lead to a variety of adverse health outcomes.¹⁷ ⁴²

The EPA has set a MCLG of 0 mg/L for total coliforms, with an enforceable maximum contaminant level (MCL) allowing 5% of all samples within a single month to test positive for the presence of coliforms.¹⁷ The number of people a public water system serves determines the frequency of required testing.⁴³ For example, in 2014 New York City had an estimated population of 8.5 million people and each month the city tested an average of 818 samples, totaling 9,818 for the year.⁴⁴ Based on these figures, a total of 41 samples per month would be allowed to test positive for coliforms. (9,818 samples ÷ 12 months = 818 samples per month; 818 samples x 0.05 = 41 samples allowed to contain coliforms). As is the case in many large cities, one to two percent of samples test positive for coliforms during the peak months, but anything beyond the 5% threshold would be considered a public health hazard and would trigger mandatory remediation.⁴⁴

Escherichia coli (E. coli) is a well-known coliform that is included in total coliform measurements but is often tested for separately.⁴⁵ Most E. coli live in the human gut where they produce vitamin K and defend the body against disease-causing bacteria. However, some strains, such as O157:H7, excrete toxic chemicals that can be life-threatening.⁴⁶ E. coli is transmitted in a number of ways including contaminated food and water and cross-contamination from fecal matter.⁴⁷ According to CDC data from a 2012 report, in the U.S., E. coli (STEC) infections result in more than 3,600 hospitalizations and 30 deaths annually, with most cases being attributed to STEC O157:H7. ⁴⁸ Exposure to E. coli can cause illness and generally affects the digestive system but can also impact the blood stream.⁴⁹

The EPA MCLG for E. coli is 0 mg/L, but the contaminant limit allows for occasional positive readings that may result from faulty measurements.¹⁹ For E. coli, any individual sampling station may not test positive for bacteria twice in a row if one of those samples contains E. coli. If violations occur, municipalities must make public warning announcements and take action as directed by the EPA.¹⁹

The EPA notes that anyone can become infected with E. coli O157:H7, but those at greatest risk of developing a serious illness from exposure are the elderly and children under the age of five.⁵⁰

Health Effects

Digestive System

Diarrhea, vomiting, nausea, and cramps. E. coli in drinking water is known to cause gastrointestinal disorders such as diarrhea, vomiting, nausea, and cramps.¹⁷ ⁵⁰

Solutions

1. Filtration and Reverse Osmosis

The Centers for Disease Control and Prevention (CDC) report that filtration methods (such as microfiltration (MF), ultrafiltration (UF), and nanofiltration (NF), and reverse osmosis (RO) can help to reduce and remove bacteria such as E. coli from water.⁵¹ The CDC reports that MF is moderately effective for removing bacteria such as E. coli, while UF, NF, and RO are extremely effective when it comes to removing bacteria such as E. coli.⁵¹

2. Chlorination

The EPA states that use of chlorine treatment as a disinfectant will effectively kill or inactivate E. coli.⁵²

3. Ozonation

The EPA states that the use of ozone to disinfect drinking water has proven to be effective for the inactivation of E. coli (not including E. coli O157:H7).⁵³

4. Ultra-Violet Sanitation

The EPA states that disinfecting water with ultra-violet light is effective in removing or inactivating E. coli (not including E. coli O157:H7).⁵⁴

2. Protozoa and Helminths

The WHO cites protozoa and helminthes (parasitic worms) among the most common causes of infection and disease in humans and animals, and are associated with a significant portion of the global disease burden.⁵⁵ Giardia lamblia and Cryptosporidium are single-celled microbes often found in water systems contaminated by sewage.⁵⁶ ⁵⁷ Much larger than bacteria, these protozoa can cause digestive problems, especially in vulnerable populations, such as young children and the elderly.⁵⁷ According to the EPA, the PHG for both Giardia and Cryptosporidium is 0 mg/L.¹⁹

The protozoa Giardia lamblia is reported to be North America’s most common intestinal parasite, causing gastrointestinal illness known as giardiasis, a diarrheal disease.⁵⁸ Water (both drinking water and recreational water) is the most common route of transmission for Giardia.⁵⁶ Giardia can also be transmitted from person to person, happening most frequently among children.⁵⁹

Cryptosporidium is a common protozoa that is widespread in water sources such as rivers, lakes, and streams and can persist for months in these environments.⁵⁷ ⁶⁰ This protozoan infects the lining of the intestines causing a disease known as cryptosporidiosis. Symptoms associated with cryptosporidiosis range from a mild upset stomach to severe diarrhea, a problem that can be life-threatening in vulnerable populations.⁶¹ Multiple waterborne disease outbreaks caused by Cryptosporidium have occurred around the world over the past several decades.⁶¹ ⁶² In 1993, a contamination of Cryptosporidium in Milwaukee, Wisconsin’s municipal water supply caused more than 400,000 people to become ill, costing an estimated $96.2 million (USD).⁶³ More recently, in 2010, approximately 27,000 residents of Östersund, Sweden were infected by cryptosporidiosis, causing individuals with chronic intestinal disease as well as young residents to face severe and long-lasting diarrhea.⁶⁴ The WHO notes that Cryptosporidium outbreaks can have very high impacts due to the large number of people that may be infected. Those most at risk are people who are severely immunocompromised.⁶⁵

Cyclospora cayetanensis is a waterborne pathogen that has been associated with several waterborne outbreaks worldwide. Of particular concern was a 2013 outbreak where 631 cases were identified across 25 U.S. states.⁶⁶ The symptoms associated with exposure include acute gastrointestinal discomfort. Symptoms arise from visiting regions where the pathogen is endemic, and is colloquially known as “traveler’s diarrhea,” with the highest risk regions including parts of Asia, the Middle East, Africa, Mexico, and Central and South America.⁶⁷

Health Effects

Digestive System

Diarrhea, nausea, abdominal cramps, and vomiting. The CDC states that infection from Cyclospora cayetanensis can result in gastrointestinal effects including diarrhea, nausea, abdominal cramps, and vomiting.⁶⁸

Giardiasis. The CDC reports that ingestion of water containing Giardia lamblia can cause giardiasis, a gastrointestinal disorder with symptoms including cramps, diarrhea, vomiting, and fatigue.⁶⁹

Cryptosporidiosis. Cryptosporidium infections due to ingestion of contaminated water are short-term and include symptoms such as diarrhea, vomiting, and nausea. The severity of the symptoms varies according to age and immune status.⁷⁰ ⁷¹

Nervous System

Keratitis. According to the CDC, infection by the protozoa Acanthamoeba (a parasite frequently found in fresh and salt water, as well as brackish water, defined as a slightly salty mix of river and sea water) via contact with contaminated water can cause amoebic keratitis, characterized by eye pain, redness, blurred vision, sensitivity to light, and excessive tearing.⁷² In addition, if not treated properly, Acanthamoeba keratitis can even lead to vision loss.⁷³

Granulomatous amebic encephalitis (GAE). The CDC reports that infection by Acanthamoeba can lead to granulomatous amebic encephalitis, an infection of the brain and spinal cord. While rare, GAE primarily affects people with compromised immune systems and can be fatal.⁷²

Solutions

1. Ultra-Violet Sanitation

According to the EPA, using ultra-violet light to disinfect watereffectively removes or inactivates Cryptosporidium and Giardia lamblia.⁷⁴

2. Ozonation

The EPA notes that while chlorination alone will not successfully eliminate Cryptosporidium from the water, a combination of ozone and chlorine disinfection is effective for removal or inactivation of Cryptosporidium.⁵³

3. Filtration and Reverse Osmosis

According to the EPA, filtration has demonstrated its effectiveness in removing both Cryptosporidium and Giardia lamblia.⁷⁵ NSF/ANSI Standard 53 filters are certified and tested to remove both Cryptosporidium and Giardia lamblia; common filters with this certification are carbon, MF, UF, and NF.⁷⁶ The CDC reports that MF, UF, NF, and RO are all highly effective for the removal of Cryptosporidium and Giardia.⁵¹

3. Cyanobacteria

Cyanobacteria is commonly identified by its color. Known as blue-green algae, cyanobacteria are naturally occurring photosynthetic aquatic life forms.

Fertilizer runoff of nitrogen and phosphorous can cause rapid cyanobacteria population growth, also known as “blooms,” which deplete oxygen from the water and kill other forms of life.

Figure 4 below shows an aerial view of a bloom of cyanobacteria caused by fertilizer and sewage runoff in Lake Atitlán, northern Guatemala.⁷⁷

Figure 4: NASA Satellite image of A “bloom” of cyanobacteria caused by fertilizer and sewage runoff.⁷⁷

Some species of cyanobacteria produce toxins that can be hazardous to humans. Microcystins and cylindrospermopsin are some of the most common toxins produced by cyanobacteria found in drinking and swimming water.⁵⁵ People can be exposed to these toxins via ingestion and also through contact with contaminated water while outdoors or showering.⁵⁵ Canadian Drinking Water Quality Standards set the maximum acceptable concentration (MAC) for cyanobacterial toxins at 0.0015 mg/L.⁷⁸ The U.S. has not yet established a drinking water guideline level for microcystins.⁷⁹

Health Effects

Digestive System

Abdominal pain, vomiting, and diarrhea. The WHO notes that, while primarily affecting the liver, cyanotoxins may cause acute gastrointestinal issues including abdominal pain, vomiting, and diarrhea.⁸⁰ ⁸¹

Liver inflammation. The National Plan for Algal Toxins and Harmful Algal Blooms as well as the U.S. EPA note that common health effects from drinking water and swimming in water contaminated with microcystins and cylindrospermopsin include liver inflammation and hemorrhage, and potential tumor growth promotion in the liver of laboratory animals.⁸² ⁸³

Digestive and Endocrine Systems

Liver tumors and cancer. The National Plan for Algal Toxins and Harmful Algal Blooms and the WHO state that long-term health effects from exposure to cyanobacteria include potential tumor growth promotion in the liver, hepatocellular carcinoma, and liver failure leading to death in laboratory animals.⁵⁵ ⁸²

Nervous System

Neural Effects. The U.S. EPA and Harmful Algal Research and Response National Environmental Science Strategy (HARRNESS) note that the anatoxin-a group of cyanotoxins affect the nervous system, causing effects such as “tingling, burning, numbness, drowsiness, incoherent speech, salivation and respiratory paralysis leading to death”.⁸² ⁸³

Respiratory System

Acute pneumonia. Exposure to microcystins and cylindrospermopsin via drinking water or bodies of water can lead to acute pneumonia.⁵⁵ ⁸²

Solutions

1. Ozonation

The EPA notes that ozone is a very effective treatment process for oxidizing extracellular microcystin, anatoxin-a and cylindrospermopsin.⁸³

2. Chlorination

The EPA notes that chlorination is an effective treatment process for oxidizing extracellular cyanotoxins when the pH is below 8. That said, chlorination is not as effective for the removal of anatoxin-a and is not recommended for removal of intracellular cyanotoxins.⁸³

3. Filtration

The EPA notes that both powdered activated carbon (PAC) and granular activated carbon (GAC) are shown to be effective in absorbing microcystin and cylindrospermopsin, although variants of microcystin may have different absorption efficiencies.⁸³ Additionally, the performance of the activated carbon for removing cyanobacteria is influenced by the amount of activated carbon and the dose of the bacteria.

The EPA also notes that NF and RO are effective in removing microcystin and cylinderospermopsin. The EPA recommends completing site-specific tests because efficiency varies by membrane pore-size distribution and water quality.⁸³

4. Legionella

Legionella is a species of bacteria naturally present in many bodies of water and is not considered a major threat when ingested. However, if inhaled, it can lead to legionellosis (commonly called Legionnaires’ Disease), a type of pneumonia. This occurs most often when inappropriately treated and managed water is used in hot tubs, showers, fountains, and large building refrigeration system and forms a mist of contaminated water. The Legionella bacteria was first identified in 1976 following an outbreak in Philadelphia, Pennsylvania and each year in the U.S. results in roughly 8,000 to 18,000 hospitalizations.⁸⁴ ⁸⁵

Health Effects

Respiratory System

Legionellosis. As a type of pneumonia, legionellosis is an infection of the lungs. It can cause coughs and shortness of breath, and also muscle- and headaches. If untreated, it can lead to lung failure and death.⁸⁴

Solutions

1. Chlorination

Legionella thrives in warm water, like that used in hot tubs and spas. Chlorinating water at 2-4 mg/L can prevent its growth in this environment; however, the elevated water temperatures also make chlorine levels fall more rapidly than water at ambient temperatures, so extra care must be taken to maintain these levels.⁸⁵

2. Building Management

Preventing Legionella growth in a large building with a complex water system requires a coordinated effort by many team members. In an effort to codify these strategies, ASHRAE has published a Standard 188: Legionella: Risk Management for Building Water Systems, a consensus-driven document authored by technically qualified committee members. It describes steps including forming a team for Legionella management, inventorying the components of the building’s water systems, analyzing potential hazards, identifying critical control points, establishing performance limits and corrective actions, and documenting procedures.⁸⁶

Disinfectants

To protect consumers from potential pathogens in drinking water, primary treatment often involves adding a disinfecting agent. Common additives include disinfectant products such as chlorine and chloramine, which provide a residual degree of disinfection so that the water does not become recontaminated as it flows from the treatment facility to the point of use.

1. Chlorine

Chlorine is the most common antimicrobial additive used in U.S. water supply.⁸⁷

In municipal systems, chlorine is added in gaseous or liquid form (as sodium hypochlorite) to control microbial growth.⁸⁷ A strong oxidizer, chlorine kills bacteria by attacking the phospholipid bilayer that forms a cell’s outer membrane and by denaturing cellular enzymes.⁸⁸ It has the lowest production and operating costs of all disinfectants and “the longest history for large continuous disinfection operations”.⁸⁹ However, chlorine in water can combine with organic matter to form compounds called disinfectant byproducts (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs), which are typically present at the tens of µg/L concentration.⁹⁰ THMs are used as indicators of other unregulated DBPs. The Maximum Residual Disinfectant Level (MRDL) for chlorine is 4 mg/L.⁸⁹

Health Effects

Respiratory System

Nose stinging or irritation. The EPA notes that chronic exposure to chlorine in drinking and swimming water at levels greater than the maximum residual disinfectant level may result in stinging or irritation to the nose.⁸⁹ ⁹¹

Digestive System

Stomach discomfort. The EPA cites stomach discomfort as an effect of drinking water containing chlorine in excess of the specified MRDL.⁹²

Rectal and colon cancer. The EPA notes that while the agency cannot conclude that there is a causal link, studies have suggested an association, albeit small, between exposure to chlorinated surface water and rectal and colon cancer.⁹³ More research is required to evaluate the strength of this association.

Nervous System

Eye stinging or irritation. According to the EPA, exposure to chlorine in drinking water at levels in excess of the MRDL can lead to eye stinging or irritation.⁸⁹ That said, a much more common source of ocular irritation takes place when exposed to chloramines frequently found in pools thanks to chlorine mixing with impurities from swimmers.⁹⁴

Solutions

1. Filtration

A research group out of Nebraska has found that activated carbon filters are an effective treatment method for removing chlorine from drinking water at the household point of use.⁹⁵ However, the performance of the activated carbon filters will depend on the concentration of the chlorine in the drinking water and also on the amount of available carbon.⁹⁶

Additionally, filters with NSF/ANSI 42 certification with claims for removing or reducing free chlorine (excess chlorine that is not bound to any contaminant) are effective in reducing overall chlorine consumption. These filters have been tested and meet the performance metrics set forth by the NSF International for removing excess chlorine from water.⁹⁷

2. Chloramines

Chloramine is a disinfectant that is commonly used as a secondary disinfectant in public water systems. Chloramine (monochloramine) provides longer-lasting water treatment while water is piped through distribution systems to consumers.⁹⁸ The use of chloramine originated, in part, to reduce the formation of potentially harmful disinfectant byproducts. Chloramine has been effective in controlling the formation of trihalomethanes (THMs) and haloacetic acids (HAAS) and may be more efficacious than chlorine against Legionella, the pathogen responsible for Legionnaire’s Disease.⁹⁸ However, chloramine fails to kill chlorine-resistant pathogens such as Cryptosporidium but may be more efficacious than chlorine against Legionella, the pathogen responsible for Legionnaire’s Disease.⁹⁸

The WHO notes that chloramine can be used as an alternative to free chlorine in water distribution systems that have both longer residence times and higher temperatures.⁵⁵ Under these conditions, the risk of nitrite formation from biofilms should be considered, especially in areas with the presence of excess ammonia.⁵⁵

There are three primary types of chloramines: mono-, di- and trichloramine. The EPA sets a MRDL for chloramines at 4 mg/L,⁸⁸ while Canada’s maximum acceptable concentration is 3 mg/L.⁹⁹ The EPA has also established a lifetime health advisory of 3 mg/L (for a 70-kg adult consuming 2 L of water per day), which is the concentration at which a lifetime of exposure will not result in adverse non-carcinogenic effects, such as organ damage, reproductive difficulty, or nervous system impairment.⁸⁸

Health Effects

Cardiovascular System

Anemia. The EPA reports that drinking water with levels of chloramine in excess of the 4 mg/L MDLG may cause anemia, a reduction in the oxygen-carrying capacity of red blood cells.⁹²

Digestive System

Stomach discomfort. The EPA cites stomach discomfort as an effect of drinking water containing chloramine in excess of the maximum residual disinfectant level.⁹²

Nervous System

Eye stinging or irritation. According to the EPA, stinging and/or irritation of the eyes is a health effect associated with exposure to chloramines in excess of the maximum residual disinfectant level in drinking and swimming water.⁹²

Integumentary System

Nose stinging or irritation. According to the EPA, stinging and/or irritation of the nose is a health effect associated with exposure to chloramines in excess of the maximum residual disinfectant level in drinking and swimming water.⁹²

Solutions

1. Filtration

Activated carbon filters may be used to remove chloramines from drinking water.⁹⁵ ¹⁰⁰ The Scottish Centre for Infection and Environmental Health states that activated carbon with low flow rates (contact time of 5-10 minutes) followed by residual ammonia adsorption using mineral zeolite media can successfully remove chloramines.¹⁰⁰ Ammonia removal can help to reduce further chloramine formation and nitrification. Performance of the activated carbon filter will depend on the concentration of the chloramine in the drinking water and on the amount of available carbon.

Disinfectant Byproducts (DBPs)

Disinfectants, such as chlorine and chloramine, are often added to protect drinking water from pathogenic microorganisms. However, when chlorine and chloramine are added to water, they sometimes react with other organic matter to produce trihalomethanes (THMs), haloacetic acids and other chemicals collectively known as disinfectant byproducts (DBPs).

In some cases, these byproducts have been shown to result in cancer and other adverse health effects in laboratory animals and humans.⁵⁵ ¹⁰¹ ¹⁰² ¹⁰³ The effects of low dose exposure to DBPs are not fully known, and warrant further study.¹⁰⁴ ¹⁰⁵

The EPA regulates four trihalomethanes (THMs) that are closely related in chemical structure: chloroform, dibromochloromethane, bromoform, and bromodichloromethane.⁸⁸ Combined, a maximum allowable amount of 80 µg/L is acceptable in drinking water. In addition, five haloacetic acids known collectively as HAA5 are monitored. These five acids – monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid – must in combination exist at levels less than 60 µg/L in drinking water.⁸⁸ It is up to the individual municipalities (like state or local governments) to impose additional limits on particular components of the THMs and HAA5 if warranted. Since these chemicals are produced by an organo-chlorine reaction, the limits pose a constraint on either the amount of chlorination used in a water system or the levels of organic matter in water subject to chlorination. Water systems that use chloramine usually produce water with lower levels of regulated DBPs, such as trihalomethanes or haloacetic acids, but can contain iodoacids, which are not currently regulated but have been shown to be highly toxic to rodents.¹⁰⁶ Other research indicates that iodoacids are some of the most toxic byproducts of water disinfection in chloramine systems.¹⁰⁷ ¹⁰⁸

The concentration of disinfectant byproducts varies based on conditions such as local rainfall and storm events, such as as flooding which may cause large deposits of organic material to wash into waterways. Thus, municipalities are increasingly relying on ozone and ultraviolet germicidal irradation (UVGI) as alternative treatment methods to reduce the dependence on chlorine, and prevent the formation of DBPs.¹⁰⁹ In addition, many water systems are controlling the formation of disinfection byproducts by lowering levels of organic matter in water prior to disinfection.

1. Haloacetic Acids (HHAs)

Haloacetic acids are a type of DBP.⁸⁸ The five HAAs regulated by the EPA (HAA5) are chloroacetic acid, dichloracetic acid, trichloracetic acid, bromoacetic acid, and dibromoacetic acid.

Dichloroacetic acid (DCA) is classified as a Group 2B carcinogen, probable human carcinogen, by the International Agency for Research on Cancer (IARC).¹¹⁰ The IARC and ToxNet note that there is insufficient human evidence to classify dichloroacetic acid as a human carcinogen.¹¹⁰ ¹¹¹

The Environmental Working Group (EWG) reports that from 2004-2009, 2,411 water utility systems serving a total of more than 33 million people had HAA concentrations greater than the EPA’s MCL of 60 µg/L.¹¹²

The WHO reports monochloroacetic acid concentrations in surface water-derived drinking water may be upwards of 82 µg/L, with a mean of 2.1 µg/L in public water systems.⁵⁵ Dichloroacetic acid has been reported in ground and surface water systems to have a mean concentration of 20 µg/L in municipal systems. Trichloroacetic acid detected in distribution systems in the U.S. has been found to have a mean concentration of 5.3 µg/L, with maximums as high as 174 µg/L. Lastly, brominated acetic acids are present in surface and groundwater systems with mean concentrations below 5 µg/L.⁵⁵

Health Effects

Reproductive System

Reproductive System Injury. The Oregon Department of Public Health informs consumers that the HAA5 levels encountered in drinking water are not expected to produce any acute health effects.¹¹³ They do note, however, that exposure over long periods of time to the maximum contaminant level (0.06 mg/L) or greater levels may lead to injury of the reproductive system. In animal studies, HAA exposure has been linked to spontaneous abortion and decreased fertility.¹¹³

Low birth weight and intrauterine growth retardation. Epidemiological studies indicate potential adverse health effects from haloacetic acid exposure in drinking water during the second and third trimesters of pregnancy.¹¹⁴ Evidence suggests that exposure to these chemicals during pregnancy may lead to low birth weight and intrauterine growth retardation.¹¹⁴ ¹¹⁵ ¹¹⁶

Urinary and Endocrine Systems

Hepatocellular carcinomas and adenomas. According to the EPA, exposure to dichloroacetic acid via drinking water has been associated with hepatocellular carcinomas and adenomas in lab rodents.¹¹⁷ ¹¹⁸

Solutions

1. Filtration

The U.S. Department of the Interior Bureau of Reclamation recommends the use of reverse osmosis for the effective removal of HAAs.¹¹⁹ This treatment technology also works to remove natural organic material (NOM) and helps to reduce future HAA5 formation.¹¹⁹

In addition, the U.S. Department of the Interior Bureau of Reclamation recommends the use of activated carbon filters for effective HAA5 adsorption and removal.¹¹⁹

2. Trihalomethanes (THMs)

Exposure to chloroform and other trihalomethanes can occur through drinking and bathing water and through and swimming in chlorinated water bodies.¹²⁰

The EPA’s MCL for trihalomethanes is 80 µg/L.¹⁷

Health Effects

Urinary System

Renal tubular necrosis and renal dysfunction. The WHO states that a universally observed toxic effect of exposure to the THMs chloroform is kidney damage, and more specific effects include renal tubular necrosis and renal dysfunction.⁹⁰

Urinary tract birth defects. A cohort study analyzing the relationship between chlorination levels and birth defects found an increase in urinary tract birth defects in municipalities where water was treated with chlorine and had high color, which indicates high levels of organic compounds.¹²¹ With an odds ratio of 1.99, this study suggests a significant association between chlorination and urinary tract birth defects.¹²¹

Digestive System

Liver cysts. Canada’s Health Deparatment, Health Canada, identifies fatty cysts in the liver as a possible health effect from exposure to trihalomethanes.⁷⁸

Urinary and Endocrine Systems

Bladder cancer. In a case-control study with 2,490 subjects in Spain, researchers found an association between estimated DBP exposure (via THM concentration) from ingestion of drinking water, dermal absorption and inhalation while showering, bathing and swimming and an increased risk of bladder cancer.¹²² Researchers noted that the risk of bladder cancer doubled (OR 2.10) with exposure levels greater than 49 µg/L, which the authors note is a common level in industrialized societies.¹²² In addition, a meta-analysis pooling data from three case-control studies conducted in France, Finland, and Spain, found a significant increase in bladder cancer risk among men exposed to THM levels greater than 25 µg/L during their lifetime.¹²³

Reproductive System

Spontaneous abortion. A multivariate analysis out of California, analyzing the relationship between drinking tap water versus bottled water while pregnant, indicates a relationship between drinking cold tap water while pregnant and spontaneous abortion.¹²⁴ With an odds ratio of 2.17 women who reported drinking high levels of cold tap water had much higher chance of experiencing a spontaneous abortion than those women who consumed no cold tap water while pregnant.¹²⁴ In addition, a prospective study found that women who consumed 5 or more glasses of water of cold tapwater containing 75 µg/L THMs per day demonstrated a higher risk (OR 1.8, 95% CI 1.1 to 3.0) of spontaneous abortion,¹²⁵

Low birthweight. Research has shown a link between consuming water with chloroform or disinfectant byproducts, such as trihalomethanes, during pregnancy and low birth weight.¹²⁶ The concentrations investigated ranged from 20 to 100 µg/L – levels commonly found in many large water systems.¹²⁶

Solutions

1. Filtration

The EPA and the U.S. Department of the Interior noted that THMs can be removed by adsorption with activated carbon filters.¹²⁷ ¹²⁸

Inorganic Contaminants

Trace elements of inorganic contaminants are common in water and are not necessarily harmful to health. In fact, many minerals such as calcium, magnesium, potassium, and sodium are essential for a healthy body, while metals such as zinc, copper, iron, manganese, selenium, and zinc are required at low levels.¹²⁹ That said, at high levels, even these essential metals can be harmful to health. Airborne exposure to certain metals such as arsenic, barium, cadmium, chromium, lead, mercury, and selenium have been associated with negative health effects including cancer, damage to the nervous system, kidney and liver complications, and even learning and behavioral problems in children.¹³⁰ ¹³¹

Metals in surface water systems can originate from natural or anthropogenic sources. Many of the anthropogenic sources include run-off from industrial and agricultural processes, along with mining and other human activities. Additionally, certain inorganic materials such as fluoride, manganese, and zinc may purposely be added to water to improve taste and aesthetic qualities.

1. Arsenic

Arsenic is an element found in the earth’s crust and is relatively abundant in some locations. The IARC classifies inorganic arsenic compounds as Group 1 carcinogens, noting that there is sufficient evidence linking arsenic with cancer in humans.¹¹⁰ The EPA enforces an MCL of 0.01 mg/L for arsenic.¹³²

In 2000, the National Resource Defense Council (NRDC) estimated that 34 million Americans in the 25 states analyzed lived in areas where water contained arsenic at levels over 0.5 µg/L.¹³³

The NRDC believes these high levels result in a greater than 1 in 10,000 chance of developing bladder, kidney, and liver cancer.¹³³

Most districts serving more than a half million people keep arsenic concentrations in water at 0.1 to 2.0 µg/L. High arsenic levels are mainly found in small water systems and wells, although water systems found in greater Albuquerque, portions of Los Angeles, and some cities in Texas and Oklahoma also have high arsenic concentrations.¹³³ ¹³⁴ ¹³⁵

There are two types of arsenic primarily found in water – trivalent (AsO3) and pentavalent (AsO5).¹³⁶ Both types are inorganic and typically come from organically occurring arsenic in the earth. Trivalent arsenic is more difficult to remove, generally because it is less charged than the pentavalent molecule, making it more difficult to remove via conventional means such as reverse osmosis.¹³⁶

Health Effects

Integumentary System

Skin damage. The EPA states that concentrations of arsenic in water above the EPA’s acceptable level of 10 ppb can cause skin discoloration, thickening of the skin, and skin damage.¹⁷

Integumentary and Endocrine Systems

Skin cancer. The WHO and the EPA indicate that skin cancer is one possible result of chronic arsenic exposure.¹³⁷ ¹³⁸ ¹³⁹

Cardiovascular System

Anemia. According to the National Academy of Sciences, acute and chronic arsenic poisoning may result in anemia.¹⁴⁰

Immune System

Leukopenia and thrombocytopenia. According to research published by the National Academy of Sciences, acute and chronic arsenic poisoning may result in leukopenia and thrombocytopenia (low platelet count).¹⁴⁰

Immunosuppression. A review by Dangleben et al. states that chronic exposure to arsenic can lead to immunosuppression.¹⁴¹

Urinary and Endocrine Systems

Bladder and kidney cancer. The World Health Organizations concludes that long-term exposure to arsenic increases the risk of developing cancer in the bladder and kidney.¹⁴² The EPA reports that long-term or chronic exposure to arsenic at levels greater than the maximum contaminant level (10 µg/L) has been linked to increases in cancer of the kidney, liver, and bladder.¹³⁸ ¹³⁹

Respiratory and Endocrine Systems

Lung cancer. The WHO and EPA both report that chronic exposure to arsenic in drinking water at levels exceeding the maximum contaminant level has been linked to lung cancer.⁵⁵ ¹³⁸ ¹³⁹

Digestive System

Inflammation of the stomach and intestine. The Agency for Toxic Substances and Disease Registry (ATSDR) reports that arsenic exposure may result in inflammation of the stomach and intestine.¹⁴³

Hepatic necrosis. The ATSDR reports that hepatic necrosis may occur from exposure to arsenic.¹⁴³

Cardiovascular System

Peripheral vascular disease. The EPA notes that chronic exposure to arsenic may lead to circulatory problems.¹⁷ The National Academy of Sciences notes that peripheral vascular disease, one of the most common cardiovascular effects, develops from chronic inorganic arsenic exposure, notably from drinking water sources and arsenic-contaminated wine or wine substitutes.¹⁴⁰

Peripheral vascular disease is the hardening of the arteries that supply blood to hands, legs, and feet. If left untreated or not treated properly it may lead to nerve and tissue damage.¹⁴⁴

Nervous System

Neurological effects. The arsenic review completed by the National Academy of Sciences notes that neurological effects from chronic arsenic exposure can range from mild nuisances such as headaches and confusion to extreme effects such as paralysis, florid encephalopathy, seizures and coma.¹⁴⁰ However, the correlation between chronic arsenic exposure and extreme neurological effects is not strong.¹⁴⁵

Solutions

1. Filtration

The Ohio Department of Health notes that reverse osmosis is a popular method for arsenic removal, enabling the elimination of up to 60 to 90% of the arsenic in the water depending on the arsenic’s valence.¹⁴⁶ Trivalent arsenic tends to be more challenging to remove from water than pentavalent arsenic. With the use of effective antioxidants, such as free chlorine, trivalent arsenic can be converted to pentavalent arsenic.¹⁴⁶ Thus, arsenic in water with residual free chlorine, or arsenic that has been treated by other effective oxidizers, exists primarily as pentavalent arsenic.

As per the recommendations of the Ohio Department of Health, if the valence of the arsenic is unknown, RO may still be effective but should be used with caution when treating drinking water with concentrations of arsenic in excess of 70 µg/L.¹⁴⁶ Since treatment of water for trivalent arsenic is estimated to provide 60% removal, this method is capable of reducing filtered water to the EPA MCL of 10 µg/L for arsenic.¹⁴⁶

The University of Nebraska identifies iron- or manganese-doped adsorbent media as an effective treatment technology for removing or reducing arsenic levels in drinking water.⁹⁵ The doped adsorbent media will act much like an activated carbon filter and remove the arsenic as it flows through the filter.⁹⁵

2. Distillation

The University of Nebraska notes that distillation is an effective treatment process for arsenic removal.⁹⁵

2. Copper

Copper is a metallic element that can naturally enter water sources, but drinking water contamination most commonly occurs through the corrosion of copper or brass household plumbing fixtures.¹⁴⁷ Water that is acidic and lacks orthophosphates (which is the case after RO treatment) tends to be especially corrosive. Sampling procedures for copper levels must come from customer piping rather than source water or water company piping. The maximum dissolved copper level allowed by the EPA is 1.3 mg/L before a treatment technique must be used.¹⁴⁷ Canadian drinking water guidelines limit copper to one mg/L, which is an aesthetic objective (AO).¹⁴⁸ The state of California currently has a PHG of limiting copper levels to 0.3 mg/L in drinking water.¹⁴⁹

The EWG reports that in 2004, 4,100 water utility systems in the U.S., which together serve more than 23 million people, reported copper concentrations above the health-based limits with the highest concentration reported reaching 7000 µg/L.¹⁵⁰

Health Effects

Digestive System

Nausea, abdominal pain, and vomiting. In a study of 60 women, researchers reported an association between short-term consumption of drinking water with aggregate copper content at ≥3 mg/l and increased incidence of nausea, abdominal pain, and vomiting.¹⁵¹ In addition, a randomized, double-blind community intervention trial in Santiago, Chile found that nausea serves as a strong indicator of an early response to acute copper exposure.¹⁵²

Liver damage. The EPA notes that liver damage may result from exposure to copper in drinking water.¹⁴⁷

Solutions

1. Filtration

The Ohio Department of Health and the University of Nebraska indicate that reverse osmosis removes or reduces copper from water.⁹⁵ ¹⁴⁶ In addition, the Institute of Agriculture and Natural Resources at the University of Nebraska states that activated carbon filters equipped with special copper-specific media are effective for copper reduction and removal.⁹⁵

2. Distillation

The University of Nebraska Institute of Agriculture and Natural Resources indicates that distillation is an effective treatment technology for copper reduction and removal.⁹⁵

3. Corrosion Control

The EPA’s lead and copper rule requires water distribution systems to reduce lead and copper levels in tapwater by improving corrosion control within service lines and piping.¹⁵³

Lead is one of the most notorious waterborne pollutants, with most lead contamination entering the water system post-treatment, absorbed from pipes of an individual home.¹⁵⁴

3. Lead

It is estimated that 10 to 20% of human exposure to lead comes from drinking water.¹⁵⁴ Lead contamination can occur through the erosion of natural deposits, but the most common sources are lead piping and water mains in older buildings.¹⁵⁴ Hot or acidic water is more likely to corrode lead pipes, leading to contamination. Lead sampling, like copper sampling, must come from customer piping rather than source water or municipal piping. The maximum lead level allowed by the EPA before requiring treatment is 0.015 mg/L.¹⁵⁴ The European Union restricts lead in drinking water to below 0.01 mg/L.¹⁵⁵

Health Effects

Nervous System

Developmental delays. Lead exposure can result in physical or mental developmental delays. The EPA reports that children exposed to lead can display deficits in attention span and learning abilities.¹⁷ According to a report issued by the EPA, lead stored in bones can be released during pregnancy, which can affect fetal brain development, making children particularly susceptible to lead poisoning.¹⁵⁶

Cardiovascular System

High blood pressure. The EPA reports that lead can contribute to high blood pressure in adults and also interfere with the production of red blood cells.¹⁵⁷

Red blood cell production. The EPA reports that chronic exposure to lead in drinking water at levels greater than the MCL can interfere with the production of red blood cells that transport oxygen throughout the body.¹⁵⁶

Urinary System

Kidney problems. The EPA reports that exposure to lead in drinking water can result in kidney problems, and that adults with kidney problems are susceptible to adverse health effects from even low levels of lead.¹⁷ ¹⁵⁶ ¹⁵⁷

Solutions

1. Filtration

The Ohio Department of Health reports that reverse osmosis is an effective method for removing and reducing lead concentrations in water.¹⁴⁶ In addition, activated carbon filtration equipped with special lead media is also a treatment option for lead reduction and removal according to the Institute of Agriculture and Natural Resources at the University of Nebraska.⁹⁵

2. Distillation

The University of Nebraska reports that distillation is an effective treatment technology for lead reduction and removal.⁹⁵

3. Corrosion Control

The EPA’s lead and copper rule requires water distribution systems to reduce lead and copper levels at the tap by improving corrosion control within service lines and piping.¹⁵³

4. Fluoride

Sodium fluoride, commonly referred to simply as fluoride, is often added to municipal water systems to prevent tooth decay.¹⁵⁸ This practice known as fluoridation has played a leading role in strengthening teeth and preventing cavities for communities across the U.S.¹⁵⁹ In some areas, natural fluoride deposits can dissolve into the water. Most toothpaste contains approximately 1,000 mg/L fluoride and it is not intended to be ingested.¹⁶⁰ Water systems typically have fluoride levels of 0.7 to 1 mg/L.¹⁶⁰

Adults absorb 60% of the fluoride they ingest, of which 99% eventually becomes incorporated into teeth and bones.¹⁶¹ The EPA has an enforceable MCL of 4 mg/L and suggests a non-enforceable secondary drinking water guideline of 2 mg/L.⁸⁸ The WHO has one of the lowest guidelines values for fluoride at 1.5 mg/L.⁵⁵

Health Effects

Skeletal System

Fluorosis. Fluorosis, an aesthetic mottling of the teeth, can occur due to fluoride exposure.¹⁶² Aside from possible discoloration, fluoride exposure has limited negative health effects. Fluorosis is most common among young people. The CDC reports that from 1999-2004 the prevalence of fluorosis among adolescents aged 12 to 15 was 41% while prevalence among adults aged 40 to 49 was 9%.¹⁶²

According to the Agency for Toxic Substances and Disease Registry, fluorosis has been known to occur in populations with drinking water that contains 25-40 mg/L fluoride.¹⁶⁰

Pain and tenderness of the bones. According to the Agency for Toxic Substances and Disease Registry, weakening of bones has been known to occur in populations where drinking water contains fluoride levels of 25-40 mg/L.¹⁶⁰ The EPA reports that it is possible for some people who drink water with excess fluoride over many years to develop bone disease.¹⁶³

Solutions

1. Filtration

The Ohio Department of Health and the EPA recommend reverse osmosis as an effective method for the removal and reduction of fluoride to levels below the MCL. ¹⁴⁶ ¹⁶³ ¹⁶⁴

2. Distillation

The EPA notes that distillation is effective for removing fluoride up to levels below 4.0 mg/L.¹⁶³

5. Nitrates

Nitrates are compounds consisting of nitrogen and oxygen that are used in fertilizers, the runoff of which can reach rivers. The EPA sets an MCL for nitrates in drinking water at 10 mg/L.¹⁷

Health Effects

Cardiovascular System

Methaemoglobinemia. Methaemoglobinemia, otherwise known as “blue baby syndrome,” is a result of the blood’s decreased ability to carry oxygen throughout the body.⁵⁵ According to the WHO, one of the most common causes of methaemoglobinemia is nitrate exposure in drinking water.⁵⁵ Symptoms include blueness near the mouth, hands, and feet. Water with more than 20 mg/L of nitrates (twice greater than the EPA limit) can be dangerous to infants, who might experience oxygen deprivation as a result of the nitrates transforming and disabling hemoglobin. Depending on the severity, the condition can quickly become lethal. Due to the high concentrations required for this effect, nitrate poisoning usually occurs in homes supplied by well water.¹⁶⁵ The WHO reports that keeping nitrate levels in drinking water sources below 50 mg/L is an effective preventative measure to limit adverse health effects associated with nitrates.⁵⁵

Endocrine System

Thyroid hypertrophy. One study reports that high levels of nitrates in drinking water (>50 mg/L) have been correlated with hypertrophy of the thyroid in adults.¹⁶⁶

Solutions

1. Filtration

The EPA recommends reverse osmosis as an effective treatment process for nitrate removal to levels below 10 mg/l.¹⁶⁷

6. Antimony

Antimony is a naturally occurring metal found in ore deposits. The most common form of antimony is antimony trioxide, which is used as a flame retardant.¹⁶⁸ Other uses for antimony include batteries, pigments, and ceramics/glass manufacturing. The EPA notes that high amounts of antimony released into land and water are associated with petroleum refinery industries, fire retardants, ceramins, electronics, and solder.¹⁶⁸ The Government of New Brunswick states that additional sources of antimony include fertilizer runoff, fossil fuel combustion products, and landfill leaching.¹⁶⁹ One report from the Institute of Environmental Geochemistry at the University of Heidelberg provides data indicating that antimony levels in bottled water can increase over time in storage due to antimony leaching from polyethylene terephthalate (PET(E)) bottles.¹⁷⁰ The data indicates a 90% increase in antimony concentrations in European bottled water after six months of storage.¹⁷⁰ Meanwhile, a study conducted in Arizona found that higher temperatures accelerated the release of antimony into the water, indicating that water bottles left in temperatures above 65 degrees Celsius could experience antimony leaching.¹⁷¹

The WHO notes that the most common source of antimony in water is from the dissolution of metal plumbing and fittings.¹⁷² A report from the ATSDR indicates that the concentration of antimony dissolved in rivers and lakes is very low, usually less than 5 ppb, with a high of 8 ppb being reported in a river polluted with antimony mining waste. In addition, soil concentrations are usually less than 1 mg/L.¹⁷³ The EPA and Canada both regulate antimony concentrations in drinking water to 0.006 mg/L.⁸⁸ ¹⁴⁸

Health Effects

Cardiovascular System

Increased blood cholesterol. The EPA notes that chronic exposure to antimony levels greater than the MCL of 6 µg/L in drinking water may result in increases in blood cholesterol.¹⁷

Decreased blood sugar. The EPA notes that chronic exposure to antimony levels greater than the MCL of 6 µg/L in drinking water may result in drops in blood sugar.¹⁷

Heart complications. A study reports that chronic exposure to antimony compounds in rats has been associated with myocardial effects and heart complications.¹⁷⁴ Additionally, the ATSDR states that breathing 2 mg/m³ can result in heart problems as displayed by altered electrocardiograms.¹⁷⁵

Digestive System

Vomiting, nausea, and diarrhea. The Government of New Brunswick reports that short-term exposure over the course of days or weeks to very high antimony concentrations (> 30 mg/L) can result in vomiting, nausea and diarrhea.¹⁶⁹ In addition, based on findings from a range of studies, the ATSDR lists vomiting and stomach ulcers as a potential result of overexposure to antimony.¹⁷⁶

Solutions

1. Filtration

The Government of New Brunswick states that while there are no devices designed specifically for antimony reduction; effective advanced filtration methods for reducing antimony levels in drinking water include filtration, coagulation, and reverse osmosis.¹⁶⁹

2. Distillation

The Government of New Brunswick states that while there are no devices designed specifically for antimony reduction; however, effective methods for reducing antimony levels in drinking water include distillation.¹⁶⁹

7. Nickel

From the sedimentation of fine particles in the atmosphere and decomposition of rocks and soil to biological decays and the disposal of waste, there are many different ways nickel enters ground and surface water as a pollutant.¹⁷⁷ In 1992 The EPA established a nickel MCLG and MCL of 100 µg/L in 1992, but this was removed in 1995. Presently, there are no EPA enforceable water standards for soluble nickel in the U.S., only a health advisory RfD of 0.02 mg/kg/day.⁸⁸ California currently has a PHG of keeping nickel levels in water at or below 12 µg/L.¹⁷⁷

According to the California Environmental Protection Agency, elevated levels of nickel may exist in drinking water due to the breakdown and corrosion of nickel-containing alloys in valves and other equipment used in water treatment and delivery systems.¹⁷⁷

The Guidelines for Drinking-Water Quality Management in New Zealand provide information related to typical nickel concentrations in the environment and in drinking water.¹⁷⁸ According to the report on inorganic contaminants nickel concentrations in seawater are generally 1 µg/L and within distribution systems, drinking water contains less than 10 µg/L. That said these levels may rise to 500 µg/L occasionally due to contamination via plumbing fittings.¹⁷⁸ ¹⁷⁹ The ATSDR toxicological report on nickel indicates that soil usually contains 4 to 80 mg/L nickel.¹⁸⁰

The IARC identifies nickel compounds as a Group 1 carcinogen, meaning that it is “known to be carcinogenic to humans”.¹⁸⁰ However, the Government of New Brunswick reports that while high concentrations of nickel are toxic, “the concentrations in water are not usually high enough to cause health concerns”.¹⁸¹

Health Effects

Digestive System

Stomach discomfort. The ATSDR reports that stomach discomfort may result from consuming drinking water with highly elevated levels of nickel, with side effects being reported among individuals who consumered water containing a nickel concentration that was 100,000 times greater than typical concentrations.¹⁸⁰

Liver damage. The ATSDR reports that elevated nickel concentrations in drinking water may also affect the liver.¹⁸⁰ Researchers observed decreased liver weight in rats and mice when exposed to 0.97 to 150 mg Ni/kg/day in the form of nickel chloride or nickel sulfate over the course of 28 days to two years.¹⁸⁰

Solutions

1. Filtration

The U.S. Department of the Interior recommends reverse osmosis for reducing or removing nickel concentrations in drinking water.¹⁸²

2. Ion Exchange

Ion exchange resins utilize a cation (positively-charged ion) to exchange acceptable ions from undesirable forms of dissolved nickel in water.⁵⁵ According to the WHO, ion exchange resins are a recommended technology for the removal of nickel from water.⁵⁵

8. Mercury

Mercury is one of the priority pollutants identified by the Clean Water Act of 1972.¹⁸⁴ It can spread to the environment through the erosion of natural deposits, discharge from oil refineries and power plants, coal slurry ponds, and runoff (leachate) from landfills. The ATSDR reports that surface water mercury levels tend to be 5 ppt (parts per trillion), a level about 1,000 times lower than the “safe” drinking water standard (MCL and MCLG) of 2 µg/l.⁸⁸ ¹⁸⁵ Young children are at a greater risk than adults for poor health effects associated with mercury exposure in excess of the EPA MCL because their bodies absorb mercury more readily.¹⁸⁶

Mercury can exist in several forms: inorganic, organic, and elemental. Inorganic mercury is usually referred to as mercury salts because when mercury binds with other elements such as chlorine or sulfur, it appears as white powders or crystals; these compounds are most commonly found in water.¹⁸⁷ Organic mercury (also known as methylmercury) is simply mercury bound with carbon and can be transformed from elemental mercury.¹⁸⁸

The most abundant organic compound found in the environment is methylmercury (CH3Hg) and is a greater health hazard than inorganic mercury.¹⁸⁵ Methylmercury is a major concern in water as it has been shown to bioaccumulate in both freshwater and saltwater fish.¹⁸⁵

At one time, one of the most common uses of elemental mercury was in thermometers. However, most mercury thermometers have now been replaced with other heat-sensitive liquids or electronic thermal sensors. Other uses for mercury include household products such as fluorescent light bulbs, thermostats and some blood pressure devices.¹⁸⁵

Health Effects

Urinary System

Kidney damage. The EPA notes that kidney damage is a possible result of exposure to elevated levels of mercury in drinking water.¹⁸⁹

Digestive System

Stomach and large intestine damage. The ATSDR reports that animals orally exposed to long-term, high concentrations of methylmercury or phenylmercury experienced damage to the stomach and large intestine.¹⁸⁵

Solutions

1. Filtration

The EPA reports that reverse osmosis is an effective treatment technology to remove or reduce mercury levels to below the MCL (2 µg/L).¹⁹⁰

Additionally, the EPA states that activated carbon filters are an effective treatment technology to reduce or remove mercury from drinking water.¹⁹⁰

Organic Contaminants

Organic contaminants are composed primarily of carbon and hydrogen and may contain other elements such as halogens (chlorine, fluorine, bromine), oxygen, sulfur, phosphorus, and nitrogen. Organic contaminants are found in trace amounts in ground and surface waters. Detection can be very difficult because quantifying such small amounts (parts per billion) requires sophisticated analytical equipment and methods such as Gas Chromatography (GC), Mass Spectrometry (MS), and ion chromatography (IC). Common sources of organic pollutants include processes related to industry and chemical runoff leaching into surface waters.

1. Polychlorinated Biphenyls (PCBs)

Polychlorinated biphenyls (PCBs) are organochlorines in which at least one, but often many, chlorine atoms are attached to each carbon atom in two connected benzene rings.¹⁹¹ Historically PCBs were widely used as coolants and dielectric fluids because of their thermal capabilities and chemical inertness. A direct effect of their chemical resistance is that they do not breakdown easily, and have a varied half-life ranging from a few days to 450 days, depending on the degree of chlorination.¹⁹¹ PCBs are categorized as persistent organic pollutants (POPs) and have been phased out since the 2001 Stockholm Convention on Persistent Organic Pollutants, an environmental treaty that went into effect in 2004.¹⁹² The treaty names 12 POP chemicals (the “Dirty Dozen”) that signatory nations have agreed to reduce or eliminate (including the production, use and/or release).¹⁹² As of 2008, the list has been extended to add nine new POPs.¹⁹³ The EPA regulates PCBs to an MCL of 0.5 µg/l and an MCLG of 0 in drinking water.¹⁹⁴

Health Effects

Urinary and Endocrine Systems

Liver cancer. A public health statement on PCBs released by the ATSDR notes that occupational exposure to PCBs may be associated with liver cancer.¹⁹⁵ Overall, there are several potential routes of human exposure to PCBs, one of which includes consumption of drinking water contaminated by PCBs.¹⁹⁵

Endocrine System

Thymus gland problems. The EPA reports that serious thymus gland problems may result from chronic exposure to PCBs in drinking water at levels greater than the EPA MCL.¹⁷

Cancer. The EPA reports that chronic exposure to PCBs at levels exceeding the MCL may result in an increased risk of cancer.¹⁷

Integumentary System

Acne and rashes. The EPA reports that chronic or prolonged exposure to PCBs at levels above the MCL may result in severe skin changes (chloracne).¹⁷ The ATSDR’s Toxicological Profile for PCBs notes that adults exposed to high PCB levels may develop rashes and acne.¹⁹⁵

Solutions

1. Filtration

The EPA reports that activated carbon is an effective treatment technology for removing or reducing PCB concentrations in drinking water to below the MCL of 0.5 µg/L.¹⁹⁴

2. Vinyl Chloride

Vinyl chloride, the monomer for polyvinyl chloride (PVC) is another high production volume (HPV) chemical with more than 17 billion pounds produced annually.¹⁹⁶ Its primary use is in PVC and copolymer synthesis. In the past, vinyl chloride was used as a refrigerant and as an ingredient in aerosols.¹⁹⁷ ¹⁹⁸ Common sources of water contamination from vinyl chloride are industrial runoff and leaching into water sources. The primary source of leaching occurs through PVC pipes and associated building materials.¹⁹⁹

Vinyl chloride is generally not a concern in surface water because it can volatize easily, meaning it readily dissolves into the atmosphere; however, removal from ground water sources is more difficult because it is not readily broken down in anaerobic conditions, is heavier than water, and may contaminate soil and enter the ground water supply.¹⁰³ ²⁰⁰ Health Canada informs consumers that exposure to vinyl chloride in drinking water, aside from ingestion, may result from inhalation and to a smaller extent, dermal absorption.²⁰⁰

According to the WHO, inhalation is the most common way individuals are exposed to vinyl chloride, but drinking water may also account for a substantial portion of daily intake in areas where the distribution network is made up of PVC piping with a high residual content of vinyl chloride monomer.⁵⁵ The presence of vinyl chloride in the environment has been reported as a product of the degradation of chlorinated solvents, including trichloroethene and tetrachloroethene.²⁰¹

Health Effects

Digestive and Endocrine Systems

Liver cancer. According to the EPA, long-term exposure to vinyl chloride in drinking water above the MCL could lead to an increased risk of cancer.¹⁷ The 12th Report on Carcinogens notes that studies have demonstrated an association between vinyl chloride exposure and liver cancer.²⁰²

Hepatic angiosarcoma. The NTP reports that numerous studies show an association between vinyl chloride exposure and cancer of the blood vessels in the liver (hepatic angiosarcoma).¹⁹⁶

Endocrine System

Cancer. The EPA reports that prolonged exposure to vinyl chloride in drinking water at levels greater than the maximum contaminant level may increase risk of cancer.¹⁷

Nervous System

Neurological effects. Reviews from Health Canada indicate an association between vinyl chloride exposure and neurological effects.²⁰⁰ Much of the cited literature is for workers exposed to very high levels of vinyl chloride through inhalation. Known effects from exposure to vinyl chloride and neurological outcomes such as headaches, nausea, dizziness, visual and hearing disturbances, and loss of consciousness.¹⁹⁸

Solutions

1. Filtration

The Illinois Department of Public Health notes that in-home activated carbon filters can remove most of the vinyl chloride from tap water.²⁰³ Health Canada recommends the use of counter-top style carbon filters as they can reduce vinyl chloride levels from 13 µg/L to well below 2 µg/L.²⁰⁰

2. Packed Tower Aeration

The EPA indicates that packed tower aeration is an effective method for reducing and removing vinyl chloride to concentrations under two µg/L.¹⁹⁹

3. Tetrachloroethylene

Tetrachloroethylene, also known as PERC, is a chlorinated hydrocarbon used as a dry-cleaning solvent, an additive in textile processing, and a metal degreasing agent. Tetrachloroethene is listed as a priority pollutant under the U.S. Clean Water Act and is a high production volume chemical, with over 1 to 10 million pounds produced or imported in 2002.²⁰⁴ The EWG notes that tetrachloroethylene pollution to ground and surface waters mainly comes from its use in the metals, chemicals, leather tanning, transportation equipment, ammunition, and petroleum refining industries.²⁰⁵ Additionally, local sources include dry cleaning establishments and machine shops which are poorly regulated and geographically dispersed.²⁰⁵

Where water volatilization cannot occur or is unlikely to take place, tetrachloroethylene can persist for upwards of 30 days (half-life from three hours to 14 days, or even >30 days in still water). Additionally, tetrachloroethene does not appear to bioaccumulate in animals or food chains.¹⁰³

A report from the WHO indicates that tetrachloroethylene concentrations in drinking water in Western European countries are generally below 1 µg/L, however concentrations up to 12.2 µg/L have been observed. High concentrations have been detected in some regions of the U.S. (up to 7.75 mg/L after a water disturbance event).²⁰⁶ A report from the EWG notes that in the U.S., about 800 water utilities have reported tetrachloroethylene in tap water since 2004, with the highest concentration of 15 µg/L found in Wisconsin.²⁰⁷ The EPA MCL for tetrachloroethylene is 5 µg/L with an MCLG of zero.²⁰⁸

Health Effects

Endocrine System

Cancers. The EPA notes that prolonged exposure to tetrachloroethylene at concentrations greater than the maximum contaminant level in drinking water may result in an increased risk of bladder cancer, non-Hodgkin lymphoma, and multiple meyloma.²⁰⁸ ²⁰⁹

Digestive and Endocrine Systems

Liver cancer. The EPA notes that chronic exposure to tetrachloroethylene above the EPA MCL can lead to liver damage and possibly cancer.¹⁷

Solutions

1. Filtration

The EPA reports that granular activated carbon filters are an effective treatment technique for removing or reducing tetrachloroethylene to concentrations lower than the MCL of 5 µg/L when used in combination with a packed power aeration.²⁰⁸

2. Packed Tower Aeration

The EPA indicates that packed tower aeration is an effective method for reducing and removing tetrachloroethylene to concentrations under 2 µg/L.²⁰⁸

4. Styrene

Styrene is a HPV chemical widely used in the production of polystyrene (Styrofoam) and other plastics and is also a minor constituent of cigarette smoke and auto emissions.²¹⁰ Drinking water may be contaminated by discharge from rubber and plastic factories as well as by landfill leaching.²¹¹

The California Office of Environmental Health Hazards Assessment (OEHHA) notes significant acute and chronic toxic effects observed in animal studies from exposure to styrene including “genotoxicity in vitro and production of various types of tumors”.²¹² Additionally, both the National Toxicology Program (NTP) and the IARC have listed styrene as a reasonably anticipated human carcinogen and a possible human carcinogen, respectively.¹⁹⁶ ²¹³ The EPA MCL for Styrene is 0.1 mg/L.²¹¹

Health Effects

Digestive System

Liver problems. According to the EPA, consuming water with styrene levels above the MCL of 0.1 mg/L can cause liver problems.¹⁷

Reproductive System

Sperm damage. A summary of animal studies reported by the ATSDR indicates that sperm damage has been observed in rats exposed to high doses of styrene.²¹⁴ Animal studies reported in the California OEHHA’s Public Health Goal (CAPHG) for styrene indicate that total epididymal spermatozoa count decreased at exposure levels above 400 mg styrene/kg per day.²¹²

Solutions

1. Filtration

The EPA reports that granular activated carbon filters in combination with packed tower aeration is an appropriate technology for removing or reducing styrene concentrations in drinking water to levels below the maximum contaminant level.²¹¹

2. Packed Tower Aeration

The EPA indicates that packed tower aeration is an effective method for reducing styrene to concentrations of less than 0.1 mg/L.²¹¹

Petroleum Contaminants

Petroleum contaminants are products and byproducts derived from the mining, refining, and manufacturing of petroleum oils. According to the WHO, petroleum oils can generate multiple low molecular weight hydrocarbon compounds with low odor thresholds in drinking water.⁵⁵ The specific contaminants that are of concern for drinking water are benzene, toluene, ethylbenzene, and xylenes (BTEX), which together are commonly referred to as BTEX. BTEX substances are volatile, aromatic hydrocarbons associated with petroleum derivatives such as gasoline and fuel oil. The American Geological Institute notes that of major gasoline compounds, BTEX substances are the most soluble, making them common indicators of gasoline contamination in water.²¹⁵

The EWG, who monitors events such as oil spills have identified several toxins common to these events including benzene, toluene, ethylbenzene, xylenes, chromium, lead, and trimethylbenzene.²¹⁶ In addition to the immediate environmental and health dangers posed by oil spills, many of the contaminants that make up crude oil are unknown. For this reason, oil pipelines and other modes of oil transport need to be assessed for their potential health and safety risks.

BTEX contamination from oil spills poses a high risk to environmental health, resulting in many years of cleanup and remediation, and significant health risks including increased risk of and developmental disorders.²¹⁷

1. Benzene

Benzene is widely used as a precursor to various materials such as detergents, dyes, pesticides, Styrofoam, nylon, and other synthetic fibers, in addition to being used as a solvent for phenol, cyclohexane, and ethylbenzene production. The CDC states that benzene is naturally found in crude oil, gasoline, and other substances such as cigarette smoke.²¹⁸ Benzene contamination in drinking water is likely caused by industrial waste discharge, gasoline leaks from storage facilities, and air pollution (emissions).¹⁴⁸

The EPA identifies benzene as a priority pollutant under the Clean Water Act.¹⁸⁴ The ATSDR’s Toxicological Profile for Benzene notes that of the 1,684 contaminated sites listed on the National Priorities List (NPL), at least 1,000 have benzene contamination.²¹⁹

The EPA currently regulates benzene to a maximum contaminant level of five µg/l in drinking water.²²⁰ The Australian Drinking Water Guidelines, on the other hand, state that no safe concentration for benzene in drinking water has been set and limit benzene to a maximum concentration of one µg/l for practical purposes as this is the limit of determination.²²¹ Further reports from the EPA indicate that an increased risk of cancer may result from prolonged exposure to drinking water with benzene at concentrations greater than the MCL.¹⁷

Benzene source pollution can come from many things, including leakage from sub-surface fuel storage tanks.²²¹

Health Effects

Cardiovascular System

Anemia. The EPA reports that exposure to benzene in drinking water at concentrations greater than the MCL may potentially be associated with anemia.¹⁷

Immune and Endocrine Systems

Leukemia. The ATSDR reports that benzene is a known human carcinogen and that occupational exposure may be associated with leukemia and possibly non-Hodgkin’s lymphoma and multiple myeloma, particularly at higher levels of exposure.²¹⁹

Nervous System

Depression of the central nervous system. The ATSDR reports that “acute inhalation and oral exposures” of benzene are associated with depression of the central nervous system and other nervous system effects, such as headaches, dizziness, confusion, and unconsciousness.²¹⁹

Solutions

1. Filtration

The EPA reports that granular activated carbon filters in combination with packed tower aeration are an effective treatment technique for the removal or reduction of benzene in water to levels below the MCL.²²⁰

2. Toluene

Toluene is very similar to benzene in both structure and properties and is a high production volume chemical. In the U.S., applications for toluene include solvents for paints and coatings, adhesives, inks, and dyes. Much like benzene, toluene is also a precursor for nylon and plastics such as polyethylene terephthalate (PET), and polyurethanes.²²²

Toluene, much like benzene, is not a common water contaminant and is most typically found near petroleum and gas deposits. The WHO reports that “concentrations of a few micrograms per liter [µg/L] have been found in surface water, groundwater, and drinking water.”²²³ The EPA MCL for toluene is 1 mg/l.²²⁴

Health Effects

Nervous System

Nervous system problems. ATSDR notes that daily, low-to-moderate occupational exposure to toluene can result in loss of appetite, memory loss, and hearing and color vision loss.²²² In mice, drinking water contaminated with toluene led to various effects on levels of neurotransmitters, depending on the specific dose.²²²

Reproductive System

Birth defects. A recent ATSDR report notes that exposure to high levels of toluene during pregnancy may lead to birth defects and other health problems.²²² The WHO also notes that toluene causes embryotoxic and fetotoxic effects.⁵⁵

Solutions

1. Filtration

The EPA reports that granular activated carbon filters in combination with packed tower aeration are an effective treatment technique for the removal or reduction of toluene to meet the regulated MCL.²²⁴

3. Ethylbenzene

Ethylbenzene is a naturally occurring component of crude oil and is also a combustion byproduct. The majority of ethylbenzene is produced through reactions with benzene, using ethylene and aluminum chloride as catalysts.²²⁵ The significant level of production and use of ethylbenzene in industrial processes creates the potential for contamination of air, soil, and water sources.²²⁶ Contamination of water sources can occur through industry discharge and leaks from underground fuel storage tanks and other locations where there are concentrated concentrations of ethylbenzene. The ATSDR reports that ethylbenzene passes into the air easily from water and soil and can contaminate groundwater.²²⁶

Concentrations of ethylbenzene in drinking water are generally very low. The EPA reports that ethylbenzene in concentrations greater than the MCL of 700 µg/L. can result in a variety of negative health outcomes.²²⁷

Health Effects

Nervous System

Drowsiness, fatigue, and headache. The EPA reports that for short-term exposure, common health effects include drowsiness, fatigue, and headache.²²⁸

Damage to the central nervous system. Long-term exposures to ethylbenzene have the potential to cause damage to the central nervous system.²²⁸

Respiratory System

Respiratory irritation. The EPA reports that short-term exposure to ethylbenzene may lead to respiratory irritation.²²⁸

Urinary System

Kidney damage. The EPA reports that long-term exposure to ethylbenzene at concentrations greater than the MCL may result in kidney damage.¹⁷

Digestive System

Liver damage. The EPA reports that long-term exposure to ethylbenzene at concentrations greater than the MCL may result in liver damage.¹⁷

Solutions

1. Filtration The EPA reports that granular activated carbon filters are an effective treatment technology for the removal or reduction of ethylbenzene to levels below the MCL.²²⁷

4. Xylenes

Xylenes are HPV chemicals with 18 billion pounds produced in 2006 in the U.S.²²⁹ Typical applications of xylenes include solvents for the printing, rubber, and leather industries. They are also used as ingredients in paper and fabric coatings and as intermediates in plastic synthesis, much like the other BTEX substances. Common sources of xylene contamination include gasoline, paint thinners, and industrial runoff and leaching. Xylenes are typically reported as a total value because there are three isomers: meta (m-), ortho (o-), and para (p-).²²⁹

The WHO states that concentrations up to 8 µg/L have been reported in surface, ground, and drinking water.²³⁰ Additionally, levels of up to a few milligrams per liter have been found in groundwater polluted by point emissions.²³¹ Xylenes, like ethylbenzene, also have the potential to penetrate plastic pipes via contaminated soil.²³¹ However, the ATSDR notes that everyday exposure to background levels of xylenes haven’t been found to result in any health effects.²²⁹ The EPA MCL for xylenes is 10 mg/L.²³²

Health Effects

Nervous System

Nervous system damage. The ATSDR indicates that acute exposure to high levels of xylene can result in delayed responses to visual stimuli and impaired memory.²²⁹ Furthermore, both short- and long-term exposure to high concentrations can also cause nausea, dizziness, headaches, lack of muscle coordination, confusion, and changes in the sense of balance. However, the report notes that while xylene ingestion through contaminated water sources is possible and represents a potential area of concern, many of the studies exploring the health effects of xylene on humans are based on exposure through inhalation. Animal studies focusing on oral exposure seem to support trends observed in inhalation-based studies.²²⁹

Respiratory System

Respiratory difficulties. According to the ATSDR, short-term exposures to concentrations of xylene above the MCL can lead to nose and throat irritation, labored breathing, and impaired pulmonary function.²²⁹

Solutions

1. Filtration The EPA reports that granular activated carbon filters with packed tower aeration are an effective treatment technology for the removal or reduction of xylenes to below the MCL.²³²

Pesticides and Herbicides

Pesticides and herbicides are chemicals used to control, kill, or repel insects, rodents and fungi, and can eventually make their way into the water supply (Figure 5).

Figure 5: Water pathways for pesticides.²³³

The U.S. uses approximately 4.5 billion pounds of active pesticide ingredients in a typical year.²³⁴ Herbicides and pesticides are most commonly used in large-scale, industrial farming. Pesticides are also regularly used in public areas such as parks, in and around schools, office buildings and hospitals, as well as by homeowners struggling with pest control.²³⁴ From the 1960s through the 1990s, industrial, home and agricultural pesticide use increased by 50% and as of 2007 had slightly decreased according to the latest figures release by the EPA.²³⁵ ²³⁶ In 1994, approximately 74% of Americans used some type of pesticide.²³⁷ As pesticide use has increased, so has the transport of chemicals into streams, where they may transfer up the food chain into fish and seep into groundwater. A U.S. Geological Survey from the 1990s detected pesticide compounds in nearly every stream in agricultural, urban, and mixed-use areas, and also in approximately 30 to 60% of the groundwater. However, tests of water wells indicated concentrations below human health benchmarks.²³⁷

Figure 6a: Occurrence of pesticides in U.S. water from 1992-2001, Data from the U.s. Geological survey.²³⁷

Figure 6b: Occurrence of pesticides in U.S. water from 1992-2001, Data from the U.s. Geological survey.²³⁷

When herbicides or pesticides are found in water supplies, they are not normally present in high enough concentrations to cause acute health effects.

However, there are concerns about long-term effects, and for their potential to cause chronic health problems.²³⁸ The United Nations Environment Program has found a large regional correlation between pesticide contamination and human health in the Aral Sea region, where runoff increased the incidence of “oncological, pulmonary, and hematological morbidity, as well as congenital deformities and immune system deficiencies”.²³⁸ The EPA has developed human health benchmarks for approximately 350 pesticides and herbicides in order to determine health risks.⁸⁸ There are enforceable MCLs for several farm chemicals that have been linked to kidney, liver, gastrointestinal, and reproductive problems, cataracts, and cancer, including the herbicides dalapon and dinoseb, and the pesticides endrin and heptachlor.⁸⁸

Figure 7: Occurrence of pesticides in U.S. water from 1992-2001, Data from the U.s. Geological survey.²³⁷

1. Atrazine

Atrazine is one of the most widely used herbicides in the U.S. and is one of the most common herbicides found in drinking water.²³⁹ The herbicide is applied to crops (most commonly to corn) to fend off weeds. Atrazine contaminates source waters through agricultural runoff and also tends to evaporate and re-deposit with rain. Atrazine is found at particularly high levels in drinking water during spring runoff.²³⁹

The current EPA MCL for atrazine in drinking water is 3 µg/L⁸⁸ and in Canada it is 5 µg/L.²⁴⁰ The Australian Drinking Water Guidelines have a maximum contaminant guideline for atrazine of 20 µg/L.²²¹

The Australian Drinking Water Guidelines indicate that through spillage or misuse, atrazine is not a health concern unless it is present in concentrations greater than 20 µg/L, and even minor excursions above this level do not pose health risks unless exposure is over a significant period of time.²²¹

The WHO reports that concentrations in drinking water rarely exceed 2 µg/L, and are commonly well below 0.1 µg/L.⁵⁵

Health Effects

Cardiovascular System

Cardiovascular system problems. The EPA reports that many years of exposure to atrazine at levels higher than the MCL could lead to cardiovascular system problems.¹⁷ ²⁴¹ The Australian Drinking Water Guidelines report that doses of 33 mg/kg of body weight/day resulted in increased heart rate, myocardial degeneration and a decreased heart weight in an animal study.²²¹

Solutions

1. Filtration

The EPA reports that granular activated carbon filters are an effective treatment technology for removing or reducing atrazine concentrations to below the MCL.²⁴¹

2. 2,4-D

2,4-Dichlorophenoxyacetic acid, more commonly known as 2,4-D, is a major herbicide applied to wheat, barley, oats, sorghum, rice, and sugarcane. The EWG notes that 2,4-D is also applied to golf courses and lawns.²⁴² With such widespread use, 2,4-D is susceptible to running off or leaching into ground and surface water sources.²⁴²

The Australian Drinking Water Guidelines report that 2,4-D does not pose a health risk through spillage or misuse unless concentrations exceed 30 µg/L.²²¹ The WHO reports that typical concentrations of 2,4-D in drinking water are usually below 0.5 µg/L, although concentrations as high as 30 µg/L have been observed.⁵⁵ The EPA MCL is 70 µg/L.⁸⁸

Health Effects

Endocrine System

Adrenal gland problems. The EPA reports that chronic exposure to 2,4-D in excess of the MCL may result in adrenal gland problems.¹⁷

Thyroid effects. In a recent memo responding to comments regarding the use of 2,4-D, the EPA reported that thyroid toxicity was a possible effect of high exposure to 2,4-D that needed additional testing to increase certainty.²⁴³ One human exposure study in males found that high exposure to 2,4-D was associated with hypothyroidism.²⁴⁴

Urinary System

Kidney problems. The EPA reports that chronic exposure to 2,4-D at levels greater than the MCL may result in kidney damage.²⁴⁵ The Australian Drinking Water Guidelines report that 3-month dietary studies in mice, rats, and dogs reported effects on the kidneys at doses of 45 mg/kg body weight/day, 5 mg/kg body weight/day, and 3 mg/kg body weight/day, respectively.²²¹

Immune System

Non-Hodgkin’s lymphoma. The California Environmental Protection Agency (Cal/EPA) cites research indicating that 2,4-D exposures in farmers can lead to non-Hodgkin’s lymphoma.²⁴⁶ However, typical exposure concentrations in these populations are much greater than those seen in drinking water. Health Canada reports that non-Hodgkin’s lymphoma is associated with concentrations of 2, 4-D at 70 to 460 µg/L in water and soil.²⁴⁷

Reproductive System

Sex chromosome loss. The EWG reports that some animal studies indicate that high exposures to 2,4-D are associated with genetic effects including sex chromosome loss.²⁴² One such study found an increase in chromatid and chromosome breaks in male rats exposed to two different concentrations of pesticide formulation.²⁴⁸

Solutions

1. Filtration

The EPA reports that granulated activated carbon filters are an effective treatment technique for the reduction or removal of 2,4-D to below the established MCL.²⁴⁵ The WHO indicates that concentrations of 0.1 µg/L should be achievable through the use of granular activated carbon.⁵⁵

3. Glyphosate

Glyphosate is a general use or non-selective herbicide used in many pesticide formulations including Roundup® and Rodeo®.²⁴⁹ As an herbicide, it is used to control a variety of broadleaf weeds and grasses in agriculture, lawns, roadsides, and forestry.²⁴⁹ Exposures to glyphosate may result from normal use and include spray drift, residue in food crops, and from runoff into drinking water sources. The EPA sets an MCL for glyphosate at 700 µg/L.²⁵⁰

Health Effects

Urinary System

Kidney problems. The EPA reports that some people who drink water containing glyphosate in excess of the MCL over the course of many years can experience kidney problems.²⁵¹

Reproductive System

Reproductive difficulties. The EPA reports that reproductive difficulties are a possible health effect of long-term exposure to drinking water containing glyphosates in excess of the EPA MCL.¹⁷ ²⁵¹

Solutions

1. Filtration

The EPA reports that granular activated carbon filters are an effective treatment technique for the reduction or removal of glyphosate to levels below the MCL.²⁵¹

4. Simazine

Simazine is another herbicide that is widely used in agriculture to control weeds.⁴² It is often combined with the herbicide atrazine to treat corn. Simazine is also used on deep-rooted crops such as artichokes, broad beans, and citrus plants, as well as in non-crop settings such as farm ponds and fish hatcheries.⁴² Acute effects from high levels of simazine exposure include decreases in weight and changes in blood.²⁵²

The WHO reports that simazine is typically detected in ground and surface water samples at concentrations up to a few micrograms per liter.⁵⁵ The EPA MCL for simazine is 4 µg/L.²⁵³

Health Effects

Cardiovascular System

Blood damage. The EPA reports that exposure to high levels of the herbicide simazine is linked to changes in blood.²⁵⁴

Reproductive and Endocrine Systems

Mammary gland and ovarian tumors. Scientists have linked simazine with mammary gland tumors and ovarian toxicity in rats.²⁵⁵ Following long-term exposure in rats, simazine has been shown to increase the levels of estrogen in the blood along with the human growth hormone, in addition to decreasing levels of prolactin and progesterone.²⁵⁵ ²⁵⁶

Solutions

1. Filtration

The EPA reports that granular activated carbon filters are an effective treatment technique for the removal or reduction of simazine in drinking water to levels below the MCL.²⁵⁴ The WHO indicates that the use of granular activated carbon should reduce water simazine levels to 0.1 µg/L.⁵⁵

Taste and Aesthetics

In addition to mandatory water quality standards, the EPA has also established non-enforceable National Secondary Drinking Water Regulations (NSDWRs).¹⁸ The NSDWRs set secondary maximum contaminant levels (SMCLs) for 15 contaminants that are not known to cause adverse health effects at the EPA-identified concentrations. According to the EPA, when levels exceed the SMCLs color, taste, odor, and aesthetics of drinking water may be compromised.¹⁸ The elements that follow closely resemble the list provided by the EPA; any contaminant additions or exclusions from that list in the following section are based on contaminants identified by other major regulatory agencies throughout the world.

1. Total Dissolved Solids (TDS)

Total dissolved solids (TDS) are the remnants of both inorganic and organic matter that are dissolved in solutions.²⁵⁷ TDS differ from suspended solids in that the contaminants are dissolved so that they cannot be easily removed. TDS will affect the aesthetic qualities of water, including taste and appearance. Primary sources of TDS contamination include agricultural and residential runoff, leaching of contaminated soil and water source pollution from industrial or sewage treatment plants. Other common sources include storm water and roadway runoff. Because industrial and agricultural sources are primary pollutants, TDS are most commonly comprised of nitrates, sodium, potassium, chloride, calcium, and phosphates.²⁵⁷ The EPA secondary MCL for Total Dissolved Solids is 500 mg/L.⁸⁸

Health Effects

Comfort and Focus

Taste and clarity. According to the EPA, high concentrations of total dissolved solids can make water unpalatable and can also impact water clarity.²⁵⁸

Solutions

1. Filtration

TDS levels can be reduced with the use of sediment filters that are in compliance with NSF International drinking water treatment unit (DWTU) standards and have verified claims for TDS reduction.⁷⁶

Reverse osmosis systems certified for compliance with NSF International DWTU standards with verified claims for TDS reduction are effective for the reduction of TDS in drinking water.⁷⁶

2. Suspended Solids

Suspended solids are referred to as sediment and are the visible impurities in water.²⁵⁹ Turbidity describes the effect of suspended particles or solids that cloud water or the deflection that occurs when light passes through a standard amount of water, measured in nephelometric turbidity units (NTU). Total suspended solids (TSS), on the other hand, measure the amount of matter in water, or the total dry weight of all non-dissolved solids in the liquid (mg/L).²⁵⁹

Water with high turbidity is not inherently unhealthy, although it can be aesthetically unappealing.²⁶⁰ Often, the solids are just sulfates and chlorides, which do no more than affect taste and appearance. However, elevated TSS levels may be indicative of problems in the filtration process, which may signify that other contaminants have not been adequately removed. Turbidity can provide food and shelter for pathogens in piping or distribution systems, possibly leading to waterborne diseases.²⁶⁰

The EPA has set the MCL for turbidity at less than one NTU for surface water systems that use conventional or direct filtration, indicating that at no time should turbidity levels exceed those limits.²⁶¹ Samples for turbidity are expected to be less than or equal to 0.3 NTU in at least 95% of the samples taken in any month.²⁶² Surface water systems that utilize slow sand or diatomaceous earth filtration must have water that at no time exceeds five NTU, with 95% of samples remaining under one NTU in any month. Lastly, surface water systems that use alternative filtration methods (other than conventional, direct, slow sand, and diatomaceous earth filtration) are at no time to exceed 5 NTU, while samples for turbidity are required to be equal to or less than 0.5 NTU in at least 95% of samples in any month.²⁶³ Some water supplies, including New York City’s, have obtained filtration waivers regarding the turbidity requirement by implementing extensive watershed control programs to preserve the quality of the source. These systems follow turbidity limits set at the state level.²⁶²

Health Effects

Digestive System

Nausea, cramps, and diarrhea. High turbidity has been associated with the growth of pathogens that may cause symptoms including nausea, cramps, and diarrhea.¹⁷

Nervous System

Headaches. High turbidity has been shown to promote the growth of pathogens that can cause headaches.¹⁷

Comfort and Focus

Appearance. High turbidity can make water appear cloudy and aesthetically unappealing.²⁶⁰

Solutions

1. Filtration

Sediment filters are an effective treatment technology for the removal of suspended solids in water.²⁶³ Manufacturer’s specifications should be considered when choosing the proper sediment filter.

Filters that have been certified for compliance with turbidity reduction claims (typically certified under NSF/ANSI Standard 53) will provide turbidity reduction to levels that meet the NSF standard for turbidity reduction.⁷⁶

The EPA recommends diatomaceous earth as an effective treatment technique for the reduction or removal of turbidity in drinking water.²⁶⁴

3. Iron

Iron is the fourth most abundant element by weight found in the earth’s crust and commonly occurs in soil and rocks as oxides, sulfides, and carbonate materials.²⁶⁵ The WHO reports that iron concentrations found in natural fresh waters range from 0.5 to 50 mg/L.⁵⁵

Iron in the water supply arises from natural deposits that dissolve in the watershed but can also be a result of “iron coagulants or the corrosion of steel and cast iron pipes”.⁵⁵

The EPA suggests a non-enforceable secondary drinking water guideline for iron levels in drinking water of 0.3 mg/L.¹⁸ Information from the Guidelines for Drinking Water Quality Management of New Zealand provides a taste threshold for iron as low as 0.05 to 0.1 mg/L in water, and iron content can become objectionable above 1 mg/L.²⁶⁵

Health Effects

Comfort and Focus

Taste. Water concentrations of iron in excess of the EPA secondary MCL of 0.3 mg/L can have a metallic taste.¹⁸

Appearance. High iron concentrations may result in water with a rust-brown appearance and can cause staining of laundry and plumbing fixtures.²⁶⁵

Solutions

1. Filtration

The EPA reports that the use of activated carbon filters, distillation, and reverse osmosis can be used to remove secondary contaminants such as iron from drinking water.²⁶⁶

Specific filters such as Birm filters are recommended by Penn State’s College of Agricultural Sciences for removing iron in private water systems in Pennsylvania, with the EPA also endorsing their effectiveness.²⁶⁷ ²⁶⁸

In addition, Greensand filters have been proven effective for the reduction and removal of iron in drinking water.²⁶⁹

2. Chlorination

The WHO reports that the addition of chlorine dioxide can be effective in controlling iron content in drinking water.²⁷⁰

3. Corrosion Control

EPA states that corrosion control is an effective method for addressing the presence of iron in drinking water.¹⁸

Chlorides are combinations of chlorine with other elements such as sodium, calcium or potassium. These compounds often naturally dissolve into the water from rocks, and can also enter water systems from fertilizer-polluted runoff.

4. Chlorides

The EPA suggests a non-enforceable secondary drinking water guideline for chlorides of 250 mg/L.⁸⁸ Drinking water regulations in Japan, on the other hand, enforce a chloride ion limit of 200 mg/L.²⁷¹

Health Effects

Endocrine System

Sodium chloride metabolism. Aside from their potential to impair sodium chloride metabolism, chlorides have not been detected as toxic to humans. Excessive chlorides in water may result in impaired sodium chloride metabolism which can lead to congestive heart failure.²⁷² ²⁷³

Cardiovascular System

Cardiovascular risks. Excessive chloride in drinking water may result in high sodium levels that can potentially pose cardiovascular risks for those who are on limited sodium diets due to blood pressure issues.⁹⁵

Comfort and Focus

Taste. High concentrations of chlorides can give water an unpleasant mineral taste.²⁷² Specifically, the EPA states that chloride levels in excess of the secondary MCL of 250 mg/L can result in a salty taste in water.¹⁸

Solutions

1. Filtration

The New Hampshire Department of Environmental Services notes that reverse osmosis is an effective treatment technique for removing chlorides.²⁷⁴

1. Distillation

The New Hampshire Department of Environmental Services notes that distillation is an effective treatment technique for removing chlorides.²⁷⁴

Aluminum is the most abundant metal on earth and is used in a wide array of domestic and industrial applications.

5. Aluminum

Aluminum sulfate (or alum) is also sometimes added during water treatment to remove suspended particles. While effective at removing suspended particles, alum can remain in the water after it reaches consumers. In some areas, aluminum that is naturally present in the soil can also enter the water system. Aluminum falls under the National Secondary Drinking Water Regulations (NSDWRs) and is limited under these guidelines to 0.05 to 0.2 mg/L.⁸⁸

The WHO recognizes the positive association between aluminum exposure in drinking water and Alzheimer’s disease that has been established in some epidemiological studies.⁵⁵ The WHO, however, states strong reservations about inferring a causal relationship due to confounding factors not being addressed in these studies. Furthermore, the WHO recommends a health-based value of 0.9 mg/L as a provisional tolerable weekly intake (PTWI) for an assumed 60 kg adult consuming 2L of water per day. Overall, aluminum residuals in large systems should not exceed 0.1 mg/L and should not exceed 0.2 mg/L in small facilities.⁵⁵

Health Effects

Nervous System

Parkinson’s disease, Alzheimer’s disease, and dementia. When present in drinking water at high concentrations, aluminum can result in neurological damage. Several studies suggest a possible link between aluminum intake and Parkinson’s disease, Alzheimer’s disease,²⁷⁵ ²⁷⁶ and other forms of dementia.²⁷⁵ ²⁷⁷ In a prospective cohort study of 3,777 elderly subjects, researchers observed an association between exposure to aluminum concentrations greater than 0.1 mg/L in drinking water and both dementia and Alzheimer’s disease. The relative risk of dementia among subjects exposed to the stated aluminum concentration was 1.99. Adjusted relative risk for Alzheimer’s among subjects exposed to aluminum concentrations greater than 0.1 mg/L in drinking water was 2.14.²⁷⁵

Comfort and Focus

Appearance. The EPA notes that aluminum levels above the secondary MCL of 0.05 to 0.2 mg/L can result in colored water.¹⁸

Solutions

1. Filtration

The Ohio Department of Health identifies reverse osmosis as a useful method for removing aluminum in household drinking water.¹⁴⁶

6. Sodium

A constituent of table salt, sodium is abundant in the earth’s crust, slowly eroding into streams and rivers, and being carried to oceans where it accumulates.²⁷⁸ Many water softeners also add sodium to bind with and disable hardening minerals. Like iron, sodium is a vital nutrient, but unhealthy in high amounts.²⁷⁸ The New York State Department of Health recommends water with no more than 20 mg/L of sodium for those on severely restricted sodium diets, and a maximum limit of 270 mg/L for those on moderately restricted sodium diets.²⁷⁹ ²⁸⁰ The EPA includes sodium in its Drinking Water Contaminant Candidate List (DWCCL) in order to examine and correct the current outdated guideline. The EPA recommends a Drinking Water Equivalency Level (DWEL or guidance level) of 20 mg/L for sodium. Sodium is currently listed as a Research Priority; upon more extensive research the EPA will re-evaluate whether or not sodium should remain on the CCL.²⁸¹

Health Effects

Cardiovascular System

Increased blood pressure. Excessive sodium in drinking water may pose cardiovascular risks due to its ability to increase blood pressure in some people.⁹⁵ ²⁷⁸ Prolonged increase in blood pressure can lead to the development of hypertension.²⁸²

Comfort and Focus

Taste. Sodium levels in excess of 250 mg/L can affect the taste of water.¹⁸ In combination with high amounts of chlorides, sodium can make water taste salty.¹⁸ In combination with high amounts of sulfates, sodium can make water taste bitter.²⁸²

Solutions

1. Filtration

The New Hampshire Department of Environmental Services notes that reverse osmosis is an effective treatment technique for removing sodium.²⁷⁴

2. Distillation

The New Hampshire Department of Environmental Services states that distillation is an effective treatment technique for removing sodium.²⁷⁴

Small amounts of manganese are required for a healthy diet, but higher amounts may cause neurological damage.²⁸³

7. Manganese

Commonly found in the earth’s crust as an ore, this element is important in the metallurgy industry. Manganese is also found in tea and many infant formulas.²⁸³

The EPA suggests a non-enforceable secondary drinking water standard of 0.05 mg/L for manganese.¹⁸ Canadian drinking water guidelines list an aesthetic objective for limiting manganese concentrations to ≤ 0.05 mg/L.²⁸⁴

Health Effects

Nervous System

Neurological damage. Very high levels of manganese, resulting from direct contamination of a water source, can result in mental disturbances and tremors, particularly in the elderly.²⁸⁵

National Institute of Environmental Health Sciences (NIEHS) funded researchers at Columbia University found a significant correlation between higher concentrations of manganese in drinking water and lower scores on tests of neurocognitive function.²⁸⁶

Comfort and Focus

Taste. According to the EPA, drinking water containing manganese in excess of the EPA MCL can have a bitter, metallic taste.¹⁸

Appearance. According to the EPA, drinking water containing manganese in concentrations greater than the EPA MCL can be black to brown in color.¹⁸

Solutions

1. Ion exchange

The New York State Department of Health recommends ion exchange (water softening) as a treatment method for water with high concentrations of manganese.²⁷⁹

2. Filtration

The EPA reports that the use of activated carbon filters and reverse osmosis can be used to remove secondary contaminants, such as iron, from drinking water.²⁶⁶

Specific filters, such as Birm filters are recommended by Penn State’s College of Agricultural Sciences for removing iron in private water systems in Pennsylvania.²⁶⁸

In addtition, Greensand filters have been proven effective for the reduction and removal of iron in drinking water.²⁶⁹

3. Distillation

The EPA reports that distillation can be used to remove secondary contaminants such as iron from drinking water.²⁶⁶

8. Zinc

Zinc is an important trace element for humans, and zinc deficiencies can impair the immune system and the ability to taste.²⁸⁷ Zinc occurs naturally in small amounts in most water supplies, but a presence in large amounts is usually a result of pollution from metal smelting or coal burning.²⁸⁷ The EPA suggests a non-enforceable secondary drinking water guideline for zinc of 5 mg/L.¹⁸

Health Effects

Digestive System

Fever, nausea, vomiting, stomach cramps, and diarrhea. Zinc poisoning is possible with prolonged consumption at a concentration of 40 mg/L or greater in adults 19 and over.²⁸⁸ The WHO reports that drinking acidic liquids that have been kept in galvanized containers can cause fever, nausea, vomiting, stomach cramps, and diarrhea.²⁸⁹

Comfort and Focus

Taste. The EPA reports that zinc concentrations in drinking water in excess of the secondary MCL can cause water to have a metallic taste.¹⁸ The WHO reports that water containing zinc at levels above 3 mg/L may not be acceptable to consumers.²⁸⁹

Appearance. When boiled, water containing zinc at 3 to 5 mg/L can develop a greasy film and appear opalescent in color.²⁸⁹

Solutions

1. Ion exchange

According to the U.S. Department of the Interior Bureau of Reclamation, ion exchange resins are a recommended technology for removing zinc from water and one of the best treatment selections for use in removing zinc in municipal water systems.²⁸⁸ ²⁹⁰

2. Filtration

The U.S. Department of the Interior Bureau of Reclamation identifies reverse osmosis as one of the best methods for removing zinc in municipal drinking water.²⁸⁸

3. Distillation

The U.S. Department of the Interior Bureau of Reclamation identifies distillation as a method for zinc removal from drinking water.²⁸⁸

4. Corrosion Control

The EPA states that corrosion control is a cost-effective method for treating zinc in drinking water.¹⁸

9. Sulfates

Sulfates are salts derived from sulfuric acid that occur naturally in many minerals and can erode into water supplies. Sulfates are used in the production of fertilizers, chemicals and textiles, among numerous other industries.²⁹¹ The EPA sets a non-enforceable secondary drinking water standard for sulfates at 250 mg/L.²⁹¹

Health Effects

Digestive System

Diarrhea. According to the CDC, ingesting large amounts of sulfates has been linked to diarrhea.²⁹² The WHO notes that cathartic effects are reported when consuming drinking-water containing concentrations of sulfate exceeding 600 mg/L.²⁹¹

Comfort and Focus

Taste. EPA reports that sulfate concentrations in excess of the secondary MCL can result in water with a salty taste.¹⁸

Solutions

1. Ion exchange

According to the U.S. Department of the Interior Bureau of Reclamation, ion exchange is a useful method for removing sulfates from drinking water.²⁹³

2. Filtration

According to the U.S. Department of the Bureau of Reclamation, nanofiltration can remove approximately 98% of sulfates.²⁹³

Reverse Osmosis

RO systems remove arsenic, aluminum, barium, chloride, copper, fluoride, iron, lead, manganese, nitrate, sodium, and sulfate: substances that can affect the taste and quality of water.¹⁶⁴ RO systems certified for cyst removal can decontaminate water infected with E. coli and Giardia, but the filtration device membrane may degrade over time, reducing biological effectiveness.¹⁶⁴

RO treatment also eliminates disinfectant byproducts that arise from the use of chlorination but does not remove chlorine itself.²⁹⁵ In fact, a carbon filter or other device must remove chlorine prior to reverse osmosis filtration or the chlorine will damage the RO membrane.²⁹⁵ Dissolved gases such as odorous hydrogen sulfide, trihalomethanes, and some pesticides will pass through an RO filter.²⁹⁹

One downside of RO treatment is wastewater.¹⁶⁴ RO systems can only reduce the dissolved pollutant concentration so much, and the remaining water is then rejected by the system. Depending on the scale, the quantity of lost water can vary dramatically; for small under-the-counter RO units, as little as 20% of the water entering the system is usable.¹⁶⁴ While the rejected water is not potable, it is still safe for other uses such as watering plants or washing cars or sidewalks.

Disinfectants

Given the harmful effects of various biological contaminants (e.g., E. coli and protozoa) on human health, disinfection is a necessary step in making water safe for human consumption.³⁰⁰ The most widely used disinfectants in the U.S. include chlorine and chloramine, which are added to water at the level of municipal water supplies (not at the level of individual buildings) due to the high capital cost and complexity of the processes.⁹²

Chlorination. The most common disinfectant used in municipal water systems is chlorine, which is a strong oxidizing chemical used to kill bacteria.³⁰¹ According to the EPA, chlorine acts as a germicide by “altering cell permeability, altering cell protoplasm, inhibiting enzyme activity, and damaging the cell DNA and RNA”.³⁰¹ Because chlorine reacts strongly with lipids in cell membranes, it is more effective at killing biological pollutants with high lipid concentrations, such as bacteria.³⁰¹

Monochloramine is a form of chloramine commonly utilized by municipal water systems for the purpose of disinfection.⁹⁸ Chloramines are used to provide longer-lasting water treatment as water travels through pipes to consumers.³⁰² Although the use of chloramine was brought about in order to reduce the formation of dangerous disinfectant byproducts, chloramines only modestly reduce the levels of harmful trihalomethanes and haloacetic acids. In addition, the use of chloramines creates a variety of disinfection products that are as bad or worse than THMs,³⁰² such as N-nitrosodimethylamine (NDMA), which is a probable carcinogen.³⁰²

Ozonation. Ozonation is another disinfection method that is in use in the U.S. It works similarly to chlorine in that it kills biological contaminants via oxidization. The residuals breakdown rapidly, reducing the concentration in the water at the point-of-use, but also reducing any residual cleansing capability.⁵³

Ozone is more effective than chlorine in killing bacteria but is the least widely adopted disinfectant method in the U.S. due to its high cost compared to alternatives.⁵³

Ultraviolet (UV) Sanitation

Bombarding water with ultraviolet (UV) light – usually near the 254 nm wavelength – can serve as an alternative to chemical disinfectant additives.³⁰³ The high-energy radiation damages the DNA of microorganisms, making it impossible for them to reproduce. In water with low turbidity, UV treatment is highly effective and leaves no chemicals in water. However, while the absence of disinfectants is beneficial for humans consuming the water, it means that there is no residual cleansing and the water could become re-infected if exposed to more germs. UV treatment pairs nicely with other filters because it works best in low-turbidity water, such as the type produced by an activated carbon filter, where it can act as a final sanitizing step once the carbon filter removes the antimicrobial chlorine.⁵⁴³⁰³

Distillation

Distillation is a water purification technique whereby the water is boiled to produce vapor which then condenses as a liquid upon contact with a cool surface and is collected.⁹⁵ It is an effective method for removing numerous contaminants including heavy metals, microorganisms, organic compounds, minerals, and nitrates.

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Environmental Protection Agency. Consumer factsheet on: ETHYLBENZENE. United States Environmental Protection Agency. Washington D.C. : United States Environmental Protection Agency, 2009. https://www.epa.gov/sites/production/files/2016-09/documents/ethylbenzene.pdf
Agency for Toxic Substances and Disease Registry. Toxicological Profile for Xylene. Agency for Toxic Substances and Disease Registry, Centers for Disease Control and Prevention. Atlanta, GA : United States Department of Health and Human Services, 2007. https://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=296&tid=53
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Water A WELLography™ First Edition

Table of Contents

Copyright

Credits

Acknowledgements

Disclaimer

Welcome to WELL

How to Use this WELLography™

Introduction

Water and the Built Environment

Properties of Water

Regulatory Framework for Contaminant Management

Regulatory Process

National Primary Drinking Water Regulations

National Secondary Drinking Water Regulations

Maximum Contaminant Level Goals (MCLGs)

Maximum Contaminant Levels (MCLs)

Treatment Techniques (TT)

State Water Safety Requirements

Categorization of Water Contaminants

Microorganisms

Chemical Contaminants

Radionuclides

Defining Contaminant Levels and Regulations

Cancer Slope Factor

Lowest Observed Adverse Effect Level

No Observed Adverse Effect Level

Reference Dose

Water and the Human Body

Elements of Water

Microorganisms Present in Water Supplies

1. Total Coliforms

Health Effects

Solutions

2. Protozoa and Helminths

Health Effects

Solutions

3. Cyanobacteria

Health Effects

Solutions

4. Legionella

Health Effects

Solutions

Disinfectants

1. Chlorine

Health Effects

Solutions

2. Chloramines

Health Effects

Solutions

Disinfectant Byproducts (DBPs)

1. Haloacetic Acids (HHAs)

Health Effects

Solutions

2. Trihalomethanes (THMs)

Health Effects

Solutions

Inorganic Contaminants

1. Arsenic

Health Effects

Solutions

2. Copper

Health Effects

Solutions

3. Lead

Health Effects

Solutions

4. Fluoride

Health Effects

Solutions

5. Nitrates

Health Effects

Solutions

6. Antimony

Health Effects

Solutions

7. Nickel

Health Effects

Solutions

8. Mercury

Water A WELLography™
First Edition