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Frequently Asked Questions: Water

How is drinking water quality monitored in Oregon?
What is the difference between 'public' and 'domestic' water?
Why is drinking water an environmental public health issue?
What drinking water contaminants are tracked by EPHT?
What is arsenic (As) and what are the health effects of exposure?
What are disinfection by-products (DBP) and their health effects?
Are TTHM and HAA5 the only disinfection byproducts? 
What is nitrate (NO3) and the health effects of exposure?
What is coliform and what are the health effects of exposure?
What is copper (Cu) and what are the health effects of exposure?
What is lead (Pb) and what are the health effects of exposure?
What is mercury (Hg) and what are the health effects of exposure?
What are polychlorinated biphenyls (PCBs) and the health effects?
What is tetrachloroethylene (PCE) and the health effects?
What are the health risks of other drinking water contaminants?
If my water comes from a domestic well, how do I protect myself?
If my water comes from a domestic well, how do I protect myself?
Links for more information about water 

 

How is drinking water quality monitored in Oregon?

The US Environmental Protection Agency (EPA) regulates drinking water quality in public water systems and sets maximum concentration levels for many possible water contaminants. The Oregon Department of Human Services Drinking Water Program administers and enforces drinking water quality standards for public water systems in Oregon.
 
The program focuses on the areas of highest public health benefit and promotes voluntary compliance with drinking water standards. It emphasizes prevention of contamination through source protection, and providing technical assistance to water systems, and training of water system operators.
 
Safe drinking water means water sufficiently free from biological, chemical, radiological, or physical impurities such that individuals consuming it will not be exposed to disease or harmful physiological effects. The safety of drinking water distributed by public water systems in Oregon is regulated under state law, ORS 448, and by the federal Safe Drinking Water Act.
 

What is the difference between 'public' and 'domestic' water?

 Most drinking water, particularly in urban areas, is obtained through public water systems that serve multiple homes or entire communities. These can be groundwater wells or surface water intakes (pipes drawing from streams and rivers). If a well or intake serves more than 3 homes or connections, it is regulated as a public water system in Oregon.
 
Water systems are classified by the number of connections, and the number of people served.
 

  • Community Water Systems (CWS) have 15 or more service connections used year–round or regularly serve 25 or more year-round residents.

 

  • Nontransient Noncommunity (NTNC) systems regularly serve at least 25 of the same people over six (6) months of the year. Examples are schools and places of employment.

 

  • Noncommunity Systems serve 25 or more persons per day. These are water systems that provide water to a transient population. Examples include restaurants, campgrounds, taverns, parks, rest areas, motels, and recreational facilities.

 

  • State Regulated systems have 4 to 14 service connections or serve 10 to 24 people on a daily basis. Examples are small mobile home parks and rural residential developments.

 
In Oregon,3,151,979 of 3,583,027 residents or 88% of the population obtain their primary drinking water from a community water system. This is very similar to the current national average of 89%.
 
In rural areas, household drinking water is often obtained through a domestic water supply from a private well. In Oregon, only when a property with a well that supplies water for domestic purposes is sold must the well be tested.
 
The only tests required by law are for nitrate and total coliform bacteria. The results are reported to the Department of Human Services Drinking Water Program. There is no reliable state or national information on drinking water from these unregulated domestic water supplies.

Most drinking water, particularly in urban areas, is obtained through public water systems that serve multiple homes or entire communities. These can be groundwater wells or surface water intakes (pipes drawing from streams and rivers). If a well or intake serves more than 3 homes or connections, it is regulated as a public water system in Oregon.
 
Water systems are classified by the number of connections, and the number of people served.

  • Community Water Systems (CWS) have 15 or more service connections used year–round or regularly serve 25 or more year-round residents.
  • Nontransient Noncommunity (NTNC) systems regularly serve at least 25 of the same people over six (6) months of the year. Examples are schools and places of employment.
  • Noncommunity Systems serve 25 or more persons per day. These are water systems that provide water to a transient population. Examples include restaurants, campgrounds, taverns, parks, rest areas, motels, and recreational facilities.
  • State Regulated systems have 4 to 14 service connections or serve 10 to 24 people on a daily basis. Examples are small mobile home parks and rural residential developments.

In Oregon,3,151,979 of 3,583,027 residents or 88% of the population obtain their primary drinking water from a community water system. This is very similar to the current national average of 89%.
 
In rural areas, household drinking water is often obtained through a domestic water supply from a private well. In Oregon, only when a property with a well that supplies water for domestic purposes is sold must the well be tested.
 
The only tests required by law are for nitrate and total coliform bacteria. The results are reported to the Department of Human Services Drinking Water Program. There is no reliable state or national information on drinking water from these unregulated domestic water supplies.
 

Why is drinking water an environmental public health issue?

On average, every person consumes more than a quart of water each day. As a result, drinking water is a potentially significant route of exposure to hazardous substances. Today’s regulatory programs are designed to monitor public drinking water supplies across the United States to assure public health protection from drinking water contaminants.
 
Drinking water contaminants can cause two general kinds of harmful health effects:

  • Acute health effects generally occur within hours or days of exposure and may result from consumption of very small amounts of water. Acute effects most often result from natural pathogens such as Salmonella and Shigella; however, some chemicals (nitrate) can cause acute effects if present in high enough concentrations.
  • Chronic health effects , such cancer or organ damage, generally result from prolonged exposure to drinking water contaminants at low concentrations and the onset of disease may take many years to occur. Chronic health effects are usually associated with chemical contaminants lead and arsenic.

Every drinking water supply is vulnerable to microbial or chemical contamination of one type or another from a variety of sources. Pathogens can be present in source water from fecal material from humans or animals, or can enter the distribution system through pipe breaks or cross connections.
 
In addition to point sources such as sewage and industrial waste, a great deal of water pollution comes from non-point sources such as agricultural runoff, and storm water drainage. Common water pollutants include pesticides, lead, arsenic, and polychlorinated biphenyls (PCBs).
 
Because there are many types and sources of contaminants that can affect drinking water systems, every aspect of system management and operation is carried out with an emphasis on protecting, maintaining and improving the safety and quality of the water at all times. This is best achieved by using a concept called the multiple barrier approach: the use of both water quality protection and water treatment to provide safe public drinking water and prevent outbreaks.

What drinking water contaminants are tracked by EPHT?

The National EPHT Network currently tracks arsenic, disinfection by-products (HAA5 and TTHM), and nitrate. In addition to those contaminants, Oregon EPHT tracks coliform (fecal and total), copper, lead, mercury, polychlorinated biphenyls, and tetrachloroethylene. Descriptions of these contaminants and their health effects are listed below.

What is arsenic (As) and what are the health effects of exposure?

Arsenic is a naturally occurring mineral. In pure form arsenic is a tasteless, odorless white powder or clear crystals. It is not found in pure form in the environment. It is generally combined with oxygen, chlorine, or sulfur. These mineral (inorganic) forms of arsenic are generally more toxic than the more complex organic compounds found naturally in animal tissues, especially in fish and seafoods.
 
Soils and rocks in some areas contain arsenic that can leach into water as erosion occurs. Some arsenic containing rock is found well below the surface of the ground, and well water may be affected by the arsenic. In Oregon, the principle source of arsenic in surface water and groundwater is believed to be native rocks and soil, particularly those of volcanic origin.
 
Arsenic has been known and used as a poison for centuries. Major uses in this country have been rodent poisons, insecticides, biocides and weed killers containing arsenic in both organic and inorganic forms. Arsenic is also used as a wood preservative, and it has been used in dyes, paints and pigmenting substances. It is used in glass-making, and electronics manufacturing and leather tanning. It has been used in both human and animal medications and care products, and may be present in some food supplements.
 
Since arsenic is a basic element, it cannot be destroyed. It simply changes forms and is moved around in the environment, generally by air and water. It may stay in soil for very long periods of time, and may or may not travel through soil. Some plants absorb arsenic into their tissues as they grow.
 
Arsenic may serve a useful function in the body, but only at very low levels. If there is a useful role, the amounts found naturally in foods are enough or more than is needed. Excessive exposure is clearly harmful. At very high dosages arsenic causes immediate (acute) effects including nausea, vomiting, and diarrhea.
 
Arsenic exposure at low doses over a long period of time may not cause any immediate effects but it is known to cause skin changes that may lead to skin cancer. More recently arsenic has been found to cause other kinds of cancer including lung, colon, and bladder cancers. It is classified as a Class A (known) human carcinogen by the US Environmental Protection Agency, and has also been associated with harmful effects on the heart and the circulatory system.
 
The US Environmental Protection Agency (EPA) established a mandatory drinking water limit known as a Maximum Contaminant Level (MCL) at 10 micrograms of arsenic per liter (mcg/L) of water (also referred to as parts per billion or ppb). Formerly, the limit was 50 mcg/L, but EPA reduced the MCL to 10 ug/l because of the growing evidence that it causes cancer and other harm to humans. Non-ingestion uses of water, such as bathing, pose much less hazard, but are not entirely safe if arsenic levels are significantly above the drinking water limit.
 
Arsenic can be reduced or removed entirely from drinking water, but treatment processes are expensive and require careful maintenance and monitoring. Currently available methods include activated alumina, electrodialysis, reverse osmosis, and ion exchange resins. Alternatives to treatment may include developing an alternative source or connecting to a safe water source in your area.
 
Not all kinds of treatment are effective, and no single treatment method can remove all contaminants from water. Treatment has limitations and disadvantages. Before deciding on treatment equipment for a private water supply, you should obtain information and advice from the Department of Human Services, Drinking Water Program at 971-673-0450.

What are disinfection by-products (DBP) and their health effects?

Disinfection of drinking water is one of the major public health advances in the 20th century. One hundred years ago, typhoid and cholera epidemics were common throughout American cities. Disinfection was a major factor in reducing these epidemics. However, the disinfectants themselves can react with naturally occurring materials in the water to form unintended by-products which may pose health risks.
Many DBPs have been shown to cause cancer and reproductive and developmental effects in laboratory animals. More than 200 million people consume water that has been disinfected. Because of the large population exposed, health risks associated with DBPs, even if small, need to be taken seriously.
 
Over the past ten years, we have also learned that there are specific microbial pathogens, such as cryptosporidium, that are highly resistant to traditional disinfection practices. Cryptosporidium caused 400,000 people in Milwaukee to experience intestinal illness in 1993. More than 4,000 were hospitalized, and at least 50 deaths have been attributed to the disease. There have also been cryptosporidiosis outbreaks in Oregon, Nevada, and Georgia over the past several years.
 
A major challenge for water suppliers is how to provide protection from these microbial pathogens while simultaneously ensuring decreasing health risks from disinfection by-products. The Safe Drinking Water Act (SDWA) Amendments, signed in 1996, required EPA to develop rules to achieve these goals.
 
These new rules are a product of six years of collaboration between the water industry, environmental and public health groups, and local, state, and federal government. They further strengthen existing drinking water standards and increase protection for many water systems.
 
Disinfectant Byproducts (DBPs) include Haloacetic Acids (HAA5) and total Trihalomethanes (TTHM) which act as indicators for DBP occurrence. HAA5 is the sum of monochloroacetic, dichioroacetic, trichloroacetic, monobromo-acetic, and dibromoacetic acids. TTHM is the sum of the four chlorine and bromine-containing trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane, and bromoform).
 
The maximum contaminant level is 0.060 mg/L for HAA5 and 0.080 mg/L for TTHM. These levels are calculated as running annual averages. (A running annual average is the arithmetic average of results calculated at the end of every quarter for the previous consecutive four-quarter period.) Compliance is achieved when the running annual averages are below 0.060 mg/L and 0.080 mg/L for HAA5 and TTHM, respectively.
 
DBP monitoring applies to Community Water Systems and Non-Transient Non-Community water systems that add a chemical disinfectant (excluding U/V disinfection) to their water or that purchase from a system that adds a chemical disinfectant.

Are TTHM and HAA5 the only disinfection byproducts? 

No. TTHM and HAA5 are measured and regulated in the EPA Disinfectants and Disinfection Byproducts Rules because they function as indicators for DBP occurrence. There are many other known DBPs, as well as yet unidentified DBPs present in disinfected water. TTHM and HAA5 typically occur at higher levels than other known and unknown DBPs. Their presence is representative of the occurrence of many other chlorination DBPs; thus, a reduction in TTHM and HAA5 generally indicates a reduction of DBPs from chlorination.

What is nitrate (NO3) and the health effects of exposure?  

Nitrogen is always present in the air. It reacts with oxygen and ozone to produce nitrogen oxides of which nitrate is one. Nitrogen oxidation also occurs in growing and decomposing biological systems. Nitrate is an essential component of living things and is a major component of animal manure, human sewage, and commercial fertilizers. Nitrates and nitrites have been used for centuries as fertilizers, in explosives and as food preservatives, especially in cured meats.
 
Everyone is exposed regularly to nitrates because of their presence in foods and water. They are also formed naturally in our bodies during digestion and metabolism. Nitrates are not harmful unless exposure to them is excessive. Very young infants, people taking medications containing nitrogen, or people working with nitrates occupationally may be harmed at lower exposure levels than others.
 
Nitrate is the most commonly found contaminant in groundwater aquifers worldwide. Nitrate originates in drinking water from nitrate-containing fertilizers, sewage and septic tanks, and decaying natural material such as animal waste. Nitrate is very soluble in water, can easily migrate, and does not evaporate. 
 
The United States Environmental Protection Agency (EPA) set a maximum contaminant level (MCL) of 10 mg/L for nitrate in public water supplies. The 10 mg/L standard has been devised to protect a select group of sensitive persons (infants, pregnant and nursing women). Nitrate can interfere with the ability of the blood to carry oxygen to vital tissues in infants less than six months old. The resulting illness is called methemoglobinemia or "blue baby syndrome”.
 
A lifetime exposure of nitrate at levels above the maximum contaminant level has the potential to cause increased starchy deposits and hemorrhaging of the spleen from diuresis. It has also been suggested that nitrate ingestion may be linked to gastric or bladder cancer. This link, however, has not been firmly established and current exposure levels do not appear to put the population at risk. There is also some evidence that areas having elevated nitrate in drinking water may have increased incidence of spontaneous abortion. However, other studies have shown no association.
 
If the levels of nitrate exceed their maximum contaminant levels in a public water system, the water supplier must notify the public via newspapers, radio, TV and other means. Additional actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.
 
Elevated levels of nitrate found in well water usually indicate improper well construction or location, overuse of chemical fertilizers or improper disposal of human and animal waste in the vicinity of the well. Domestic uses of affected water for activities other than drinking, such as irrigation, washing, and bathing, do not result in nitrate absorption.
 
Heating or boiling water containing nitrate will not remove the nitrate, but may actually concentrate it. If the water supply is contaminated with nitrate above the 10 mg/L level, options to consider include using bottled water for drinking, and for food and beverage preparation, or installing a home water treatment unit.
 
Mechanical filters or chemical disinfection, such as chlorination, do not remove nitrate from water. Nitrate may successfully be removed from water using treatment processes such as ion exchange, distillation, and reverse osmosis. These treatment techniques require careful maintenance and sampling to achieve and confirm effective operation.
 
 If a treatment system is to be used, one with National Sanitation Foundation (NSF) certification should be selected. For additional information on these options, contact the Department of Human Services Drinking Water Program at (971) 673-0405.

What is coliform and what are the health effects of exposure?

Coliform is a group of bacteria commonly found in the environment. Its presence in water may indicate contamination by disease-causing microorganisms. Microorganisms that have the most significance to human health are those that cause disease, called pathogens. Examples of common pathogens include bacteria such as Salmonella and Shigella, protozoans such as Giardia and Cryptosporidium, and viruses such as hepatitis A and Norwalk. These pathogens are transmitted by the fecal-oral route of exposure; this means that feces from an infected person or animal are transmitted directly or indirectly to another person's mouth.
 
Total coliform bacteria, often called merely "coliforms", are very widely distributed in nature. Most coliforms live in the intestinal tract of man and other warm-blooded animals, so they are found in significant numbers wherever fecal (intestinal) waste or contamination is present. A few of the bacteria in this class are associated with natural plant material and therefore may be found even where fecal contamination is absent.
 
Coliforms are the most commonly used indicators of contamination in drinking water. If coliforms are found it is possible, though not certain, that the water could contain disease-causing organisms as well. Water that contains coliforms must generally be treated, at least by disinfection with chlorine, before it can be safely used for drinking water or for other domestic purposes. Until the water can be reliably disinfected, it should be boiled before consumption.
 
Fecal coliform bacteria is a subgroup of total coliform bacteria consisting of those which can grow when incubated in the laboratory at a temperature too warm for most coliforms (112 degrees). The organisms that are found by this method are more likely to be associated with fecal contamination than are total coliforms, although a few of these coliforms can also be associated with woody plant material.
 
Fecal coliforms are a better indicator of fecal contamination than total coliforms in drinking water, but the actual presence of disease-causing organisms is still not certain. Nevertheless, water containing fecal coliform bacteria should never be consumed without at least disinfection treatment. Until the water can be reliably disinfected, it should be boiled before consumption.
 
Construction or maintenance work, such as pump replacement in an existing well, can temporarily contaminate well water with coliform bacteria. Bacteria from soil, vegetation, and the tools and hands of the maintenance crew could enter the well. Before using the water, disinfect and flush the entire system and then sample for coliform.
 
Contact the Oregon Drinking Water Program at 971-673-0405 for instructions about how to disinfect a well. The safest temporary measure to kill coliform and other microorganisms in drinking water is to bring the water to a rolling boil for one full minute.
 

What is copper (Cu) and what are the health effects of exposure?

Copper is a naturally occurring metal widely dispersed over the earth as a constituent of soils, rocks, and geological formations. Copper is not destroyed or degraded in the environment. It gradually tends to return to less soluble and more stable forms in soils and in sediments under water. Since the earliest civilizations, copper has been extracted from rocks and soils and used widely by humans.
 
Due to its relative softness, it lends itself well to construction of ornaments, utensils, tools, weapons and toys. Due to its ability to kill or control algae and small organisms it is commonly used as a pesticide against insects, molds, algae, and fungi. Because of its wide presence in soils, it is a constituent of most food products and is considered an essential dietary mineral for humans and animals.
 
Hazardous levels of copper in the environment are generally due to releases of concentrated copper during mining, industrial use, deliberate application of copper-containing compounds, disposal of copper-containing materials, and accidental spills of copper materials. In drinking water, elevated levels of copper are usually due to dissolution of copper pipes, fixtures, and treatment equipment, or the application of copper compounds for algae control in source water or reservoirs. Excessive levels of copper in Oregon water are nearly always due to copper piping and bronze or brass fittings in plumbing.
 
There is no health-based drinking water standard for copper because its adverse characteristics become apparent at concentrations much lower than any known toxic effects. Copper in water can cause staining of fixtures, hair, and fabrics at levels between 0.5 and 4.0 milligrams per liter (mg/L). It also imparts a bitter taste to water at 1-5 mg/L.
 
The Environmental Protection Agency has adopted an action level of 1.3 mg/L for public water systems to avoid these economic and aesthetic effects. Systems having copper at greater levels than this action level are required to provide corrosion control treatment.
 
Copper levels greater than 1.0 mg/L may cause stomach irritation and vomiting. Persons recover quickly from these acute exposures and there are no confirmed long-term health effects from accidental or occasional exposures to drinking water containing copper at levels above the action level. However, habitual or frequent use of water having more than 1.3 mg/L copper can lead to chronic health effects. Infants or children exposed to levels of copper above the action level for weeks or months may suffer liver and kidney damage.
 
The most important avoidance techniques involve keeping copper from entering drinking water, rather than treatment for removal. This can be accomplished by:

  • Avoiding using first-draw water (water that first comes out of the tap after the system has been unused for a number of hours) for drinking or in food or beverages.
  • Removing or limiting copper or copper-containing pipes, fittings, fixtures, and equipment that is in contact with drinking water.
  • Control or elimination of copper compounds for the control of algae.

 
Treatment equipment is available that will reduce copper in drinking water through methods such as coagulation-filtration, ion exchange, lime precipitation, and osmosis. Persons are encouraged to contact the Oregon Drinking Water Program at 971-673-0405 for advice and assistance before buying or installing treatment equipment for copper removal or acidity/alkalinity adjustments.

What is lead (Pb) and what are the health effects of exposure?

Lead in its pure state is a dull gray, heavy metal which is soft and very flexible. Lead compounds may be powders of various colors, pigments in paints, and lubricating greases. In addition, lead is a component in many metal alloys and is present in many finishing materials, including ceramic glazes.
 
Because of its moldability, resistance to tarnish and rusting, and density, lead has been used to make toys, machinery parts, fishing weights, firearm ammunition, and ballast and balancing weights, and automotive batteries. Historically lead has been an ingredient in gasoline and many household products including pesticides, plumbing fixtures, interior and exterior paints, and in a variety of food utensils.
 
Prior to its ban from most automotive gasoline products in 1996, 70% of the lead used in the US was for transportation industry uses. Recent years have seen a trend of removal of lead constituents in fuels, paints, toys, food industry uses and household products; but lead continues to be present in most household environments and throughout many industrial settings.
 
Release of lead occurs by industries that use lead products, as a component of smoke when lead-containing products are burned or exposed to very high temperatures, as a component of exhaust from lead additives in fuels, and when materials containing lead are buried or dumped. Lead is extremely stable in the environment.
 
Lead is seldom found in natural waters, but it frequently enters drinking water by dissolving from piping, fittings, joining materials, and fixtures in water supply systems. Usually the only source of lead in a drinking water system is household plumbing. In its dissolved state, lead is invisible, odorless and without taste. Dissolved or suspended in water, lead is hazardous to animals and humans if it is ingested in sufficient quantities.
 
Lead that is released into the environment as fine particles or vapor will settle to the earth relatively quickly as a solid. It does not remain suspended in air nor does it travel long distances in air. However, lead in air is hazardous to humans and animals if it is inhaled or if it settles on food or other materials that are ingested.
 
Lead can cause a variety of adverse health effects when people are exposed to it at levels above the maximum contaminant level for even relatively short periods of time. These effects may include interference with red blood cell chemistry, delays in normal physical and mental development in babies and young children, slight deficits in attention span, hearing, and learning abilities of children, and slight increases in the blood pressure of some adults.
Lead does not degrade or disappear; it only changes form and location. The challenge is to minimize the amount of lead in the water we drink, the food we eat, and the air we breathe. The EPA has adopted a national action level for lead in public water systems of 0.015 milligrams of lead per liter of water (mg/L). This is a very protective standard that is aimed at protecting pregnant women and small children, the most vulnerable people in our population.
In Oregon, the challenge is principally how to prevent lead from entering our drinking water. Lead may become incorporated into drinking water in the course of treatment, storage, and delivery of water to the customer. An even greater potential for lead exposure is found in the internal plumbing of many buildings, including residential structures. Generally when unacceptable levels of lead are found in residential water, it is from building plumbing.
 
Public water suppliers are required to periodically test the household water of a certain percentage of homes. If excessive lead levels are found in these homes, but not in the water being delivered to those homes, the supplier will be required to treat the water to reduce its tendency to dissolve materials. In some cases it is necessary to replace all or part of a plumbing system or certain components in the plumbing system.
 
If your house has been tested for lead, contact your water supplier about the results of the test. If your home has not been included in a testing program, you may wish to hire a private laboratory to test it for you. Be sure you test "first-draw water." "First-draw" means the first water to come from a faucet after a period of 6-8 hours without any use; for example, the first use in the morning or after a day of absence.
 
Public water systems with levels of lead above the Action Level are required to install corrosion control treatments to prevent or reduce the leaching of lead into the water and notify the public via newspapers, radio, TV and other means. Customers will be informed of what they can do at home to lower their exposure to lead. Additional actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.

What is mercury (Hg) and what are the health effects of exposure?  

Mercury is a metallic element that, in its pure state is a heavy liquid. Elemental mercury can evaporate even at ambient temperatures, but especially when heated. In addition to this pure form (known as elemental mercury), mercury reacts with other substances to form organic and inorganic compounds.
 
Mercury occurs naturally in ores and other geologic formations and is released into the environment through various human activities. Mercury released into the environment is primarily inorganic or elemental by nature. Inorganic mercury is the most common form present in drinking water. In this form, it is not considered to be harmful to human health in the levels typically found in drinking water.
 
Organic mercury (primarily methyl mercury) is produced by specific bacterial organisms in surface waters that convert inorganic mercury into organic mercury, which is the form of mercury that poses a significant threat to human health. Methyl mercury is ingested typically by fish and bioaccumulates both in the tissues of fish and the humans that eat these fish.
 
Large predatory fish can contain as much as 100,000 times more methyl mercury than the surrounding water medium. This form is rarely present in drinking water but is a very common contaminant in the tissues of fish. In humans, it causes damage to the nervous system, brain, kidneys, and lungs, and permanently affects fetal and child development. Both inorganic and organic mercury are considered to have a more detrimental effect on children due to the fact that both forms are more easily absorbed into their systems.
 
The EPA is charged with regulating and managing mercury contamination. Several laws give the EPA this authority, including the Clean Air Act, Clean Water Act, Resource Conservation & Recovery Act, and Safe Drinking Water Act. Additionally, the Mercury-containing and Rechargeable Battery Management Act passed in 1996, phases out use of mercury in batteries, and provides for efficient and cost-effective disposal of mercury containing items.
 
There are many steps you can take to reduce the amount of mercury that gets into the environment. Everyday products, such as thermometers, fluorescent light bulbs, and vehicle convenience light switches that contain mercury can be replaced with non-mercury containing products and properly disposed of at statewide Department of Environmental Quality (DEQ) sponsored household hazardous waste collection events.

What are polychlorinated biphenyls (PCBs) and the health effects?

Polychlorinated biphenyls (PCBs) are a family of related chemicals with a complex but very stable molecular structure. There are 209 different chemical configurations included in this family. PCBs do not have distinguishing features that make them easily recognizable, and can be detected only by laboratory analyses.
 
They are practically insoluble in water but are very soluble in fats, waxes, and oils. They are not volatile so they do not evaporate and they do not degrade readily. The result is that they accumulate, particularly in animal fats and in sediments of lakes, rivers, and streams.
 
Beginning in the 1920's, PCBs were used in electrical components, as lubricants, in hydraulic fluids, as heat transfer fluids, and in coatings, plastics, and inks. PCBs are components of many industrial materials even today, though their manufacture and distribution was curtailed in the late 1970's. PCBs were extremely useful because of their low electrical conductivity, heat absorption capacity, and heat stability. For many years these compounds were considered harmless, because of their low acute toxicity.
 
PCBs do not come from any natural source. They are all manmade. They enter the environment as contaminants of water, air, or other materials. Contamination can occur through industrial discharges of contaminated air, water, or waste; by industrial accidents and spills such as transformer fires and oil spills; and by residential contamination from fluorescent light ballasts, and other consumer products that may leak contaminated oil or may contain PCBs that are released at the point of disposal.
 
PCBs do not generally degrade in the environment but tend to attach themselves to organic components in soils and other solids which are carried into water bodies and accumulate in sediments. PCBs that find their way into deep soils, deep sediments or into groundwater may persist indefinitely. This accumulation of PCBs in sediments plays an important role in the process that results in food contamination.
 
The Environmental Protection Agency and the Oregon Health Division have adopted a Maximum Contaminant Level (MCL) for PCBs of 0.0005 milligrams per liter of water (mg/L). The MCL is designed to prevent measurable PCB exposure via drinking water. This is a very conservative standard compared to those applied by the Food and Drug Administration to food products in the US. Because of the unavoidable PCB residues in some foods it is prudent to avoid exposure via drinking water.
 
The MCL is based on what is believed to be the most sensitive health effect of PCBs, their possible role in cancer causation. It is believed that PCBs at levels of 0.0005 mg/L or less, for persons drinking 2 liters of water per day for a lifetime, would pose a cancer risk of less than one in 10,000. The major source of ongoing concern for PCB exposure to the general public is contamination in foods, especially fish, meat, and dairy products which can have PCB levels as high as 5 mg/L or more.
 
It may be possible to remove entirely or reduce the contamination of water with PCBs by detergent treatment or by activated charcoal filtration or by a combination of both. Persons interested in treating water for PCB removal are encouraged to contact the Oregon Department of Human Services Drinking Water Program at 971-673-0405 for advice and assistance before buying or installing any treatment equipment.
 

What is tetrachloroethylene (PCE) and the health effects?

Tetrachloroethylene is a man-made chemical that has been widely used as a cleaning agent in the dry cleaning industry and as a metal degreaser in the manufacturing industry. It is also used as a building block for making other chemicals in the chemical manufacturing industry. PCE evaporates readily and produces a sharp, sweet smell.
 
Most PCE enters the environment by evaporating into the air from factories, storage tanks, hazardous waste sites or other contaminated areas. Once in air, PCE can take from 1 hour to 2 months to be broken down by sunlight, or wash back to the soil by rainfall. PCE may also enter soil and groundwater when contaminated materials leak or spill. PCE in the soil will tend to evaporate to the air. Some PCE may travel through the soil and contaminate groundwater.
 
Once PCE enters the groundwater, it breaks down very slowly. Humans can be exposed to PCE in groundwater if they use contaminated water for drinking or cooking. Another route of exposure is by inhalation during the use of PCE contaminated water for showering, watering lawns, or crops. PCE exposure may also occur through direct contact with contaminated water or soil. There is little information on whether PCE accumulates in plants or animals.
 
Health effects from exposure to PCE over long periods of time have been studied in animals. These animal studies have determined that PCE can cause liver and kidney damage, and certain types of cancer such as liver cancer, kidney cancer, and leukemia. Based on information in these animal studies, PCE is considered to be a "probable human carcinogen" and its use is being increasingly restricted. 
 
The Environmental Protection Agency (EPA) sets Maximum Contaminant Levels (MCLs) for chemicals in drinking water. These MCLs represent the highest concentration of a contaminant which is allowed in drinking water supplied by public water systems. MCLs are based on all the available toxicity information for the chemical and some very conservative assumptions to ensure that even the most sensitive populations are protected.
 
These assumptions include a lifetime of 70 years and an ingestion rate of 2 liters (approximately 2 quarts) of water consumed everyday during this 70 year lifetime. In the case of cancer-causing chemicals (carcinogens), the MCL is set so that a lifetime exposure to the contaminant at the MCL would result in no more than 1-100 excess cases of cancer per million people exposed. The EPA has set the MCL for PCE to be 0.005 milligrams per liter (mg/L).
 
Although the maximum allowable level for PCE is very protective of human health, it is recommended that exposure to PCE be kept as low as possible. To accomplish this, public water suppliers or other domestic well owners can take a variety of actions including closing contaminated wells, finding other water supplies, or installing treatment systems at contaminated wells consisting of granular activated carbon filtration or aeration.
 
People whose water exceeds the standard or who do not wish to consume even small amounts of PCE can take actions for short-term protection including using bottled water or using in-home treatment devices to treat water used for drinking and cooking. In addition, it may be prudent not to give livestock or household pets contaminated water to drink since toxic effects may occur. Contact the Oregon Department of Human Services Drinking Water Program at 971-673-0405 for advice and assistance before buying or installing any treatment equipment.

 

What are the health risks of other drinking water contaminants?

The Oregon Drinking Water Program provides Health Effects Information Bulletins on numerous contaminants. These fact sheets are available on the Forms/Tools/Fact Sheets page of their website at /DHS/ph/dwp/tools.shtml.

 

If my water comes from a domestic well, how do I protect myself?

If your water comes from a well serving 1 to 3 households, it is considered a private or domestic well in Oregon. If you get your water from a domestic well, you can contact the Oregon State University (OSU) Extension Service at (541) 737-6294 for information about care and protection of your well. More extensive information on household wells is available at the OSU website at: http://groundwater.orst.edu/protect/wells.html. Information is available on household water treatment systems at: /DHS/ph/dwp/docs/notices/homewat.pdf.

It is important to know that owners of domestic wells are not required to conduct sampling and testing unless there is a property transfer. It is the responsibility of the property owner to maintain the domestic well and ensure that the well water is safe to drink. The Department of Human Services and the Department of Environmental Quality recommend that domestic wells be tested regularly (once every one to two years) to ensure drinking water is safe for consumption. Testing should also be done as soon as possible if anyone in the family is experiencing chronic gastrointestinal disorders (e.g., chronic diarrhea), or other unexplained health problems.

The Department of Human Services and Department of Environmental Quality do not test (or pay for testing of) domestic wells. Unless your well involves a specific project, no state agency is funded to provide free testing. Well owners can have their well water tested at a nearby laboratory at their own expense. Depending on what type of test a well owner has done, the cost can range from $75 to $150, or more for very extensive testing. The Department of Human Services Drinking Water Program can provide a list of laboratories in your area.
Microbiological contaminants and nitrates are the most common risks for domestic well owners. The Department of Human Services and Department of Environmental Quality recommend that you also call your local County Health Department for recommendations of what to sample for in a domestic well in a particular area.

If test results from your domestic well indicate contamination, call the Department of Human Services-Drinking Water Program at (971) 673-0405 for information. They can assist with information on how to disinfect your well if you have problems with microbiological contaminants, provide fact sheets for chemicals, or information on how to address other problems.

Links for more information about water

Agency for Toxic Substances and Disease Registry (ATSDR), Department of Health and Human Services (DHHS), Centers for Disease Control and Prevention (CDC): http://www.atsdr.cdc.gov/
 
CDC, Water Quality, DHHS: http://www.cdc.gov/health/water.htm
 
Environmental Protection Agency (EPA), Consumer Confidence Reports: http://www.epa.gov/safewater/ccr/index.html
 
Environmental Protection Agency (EPA), Drinking Water Standards: http://www.epa.gov/safewater/standards.html
 
Environmental Protection Agency (EPA), Ground Water & Drinking Water: http://www.epa.gov/safewater/
 
Environmental Protection Agency (EPA), Local Drinking Water Information: http://www.epa.gov/safewater/dwinfo/index.html
 
Environmental Protection Agency (EPA), Public Drinking Water Systems Programs: http://www.epa.gov/safewater/pws/index.html
 
Environmental Protection Agency (EPA), What contaminants may be found in drinking water?: http://www.epa.gov/safewater/dwh/contams.html
 
National Environmental Public Health Tracking (NEPHT) Program, CDC, DHHS: http://www.cdc.gov/nceh/tracking/default.htm
 
National Institute of Environmental Health Sciences (NIEHS), Water Pollution, DHHS: http://www.niehs.nih.gov/health/topics/exposure/water-poll/index.cfm
 
National Sanitation Foundation:
http://www.nsf.org/consumer/drinking_water/index.asp?program=WaterTre
 
Oregon Department of Environmental Quality (DEQ): Water Quality Division: http://www.oregon.gov/DEQ/WQ/index.shtml
 
Oregon Drinking Water Program, DHS: /DHS/ph/dwp/
 
Oregon Drinking Water Program, Fact Sheets: /DHS/ph/dwp/tools.shtml#FactSheets
 
Oregon Environmental Public Health Tracking (EPHT), Department of Human Services (DHS):
/DHS/ph/epht/
 
Oregon State University (OSU), Extension Services, Groundwater in Oregon:  http://wellwater.oregonstate.edu/