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What drinking water contamination tests should you order? Here we discuss the general classes of water contaminants covered in a water test for other chemicals, phthalates, endocrine disruptors, pesticides or pesticide contamination and similar contaminants. The health effects of chemical contaminants in drinking water and drinking water monitoring requirements are also discussed in many US EPA documents (where exposure standards for more than 80 chemical contaminants are specified) as well as various state and municipal documents and water testing guides.

Readers should also see our longer article Water Quality Testing, and advice for home buyers and building owners: water contaminants, water test procedures, well shock procedures, preventing drinking water contamination, and Cheating on water tests in that document.

© 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

Deciding to When & How Test for Chemical Contaminants in Water

The list of possible chemical contaminants is long and the number of possible tests so large, and potentially costly, that some research and thinking are needed before you can make an intelligent choice on just which water tests for chemical contaminants are appropriate for a given property.

While water test labs offer package tests that can screen for a wide number of chemical contaminants for a modest fee, (See for example Standard VA FHA, Pesticides , and  Title 5- water test parameters and  Comprehensive Water Test) none of these tests guarantees that all possible contaminants that could be present have been checked for a specific well.

Be sure to review the water test alternatives with your water test consultant or lab and with the neighbors of your property - neighbors and local water testing labs often are the most aware of what specific contaminants have been found in nearby wells or in surface and ground water. Below we collect comments and advice about both common and uncommon water contaminants that might be a concern at specific water wells or in other bodies of water such as lakes or streams where contaminants may affect both humans and other animals.

The list of chemical contaminant topics in water (below) is of necessity, incomplete, and we continue to add information to this article. Readers are welcome to Contact Us by email with content suggestions or corrections for this article.

• Agricultural sprays, weed killers, etc: in 1962 in Silent Spring, Rachael Carson drew attention to poisons from insecticides, weed killers, and other common products as well as the use of sprays in agriculture, a practice that led to dangerous chemicals to the food source. Carson argued that those endocrine disrupting chemicals were more dangerous than radiation and that for the first time in history, humans were exposed to chemicals that stayed in their systems from birth to death.
• Endocrine disruptors: Readers interested in the subtle but powerful effects of hormone mimicking chemicals and endocrine disruptors that appear in the environment, their sources, effects, and risks, should also see Our Stolen Future, Theo Colborn, Dianne Dumanoski, and John Peterson Myers. Also see our notes on phthalates below.
• Iron and other minerals (such as salt) at abnormal levels in water may be a hazard to some individuals. These substances may occur naturally in the water supply. Most comprehensive water tests include a check on the levels of these substances.
• Pesticides and Septic Systems: as we discuss at OTHER CHEMICALS, people who need to dispose of un-used pesticides should not put them in building drains or toilets. In the U.S. contact your state department of environment or local health department to find the nearest local hazardous waste disposal station where you can usually drop off unwanted chemicals, paint, etc., often at no charge. See Pesticides Contamination for details of testing for pesticides. Also see Pesticide Exposure Hazards for a wider discussion of pesticide exposure hazards in buildings.
• "Phthalate Syndrome": Phthalate contamination of groundwater and wells from phthalates: in a compelling article in the New York Times in July 2009 Nicholas D. Kristof reported on the possible hazards of phthalates, chemicals that can leach into their contents and thence into the environment from some plastic food or water containers, or even toys. While we have not found any research whatsoever that tests for the appearance of phthalates in septic systems and the ground water into which septic effluent ultimately appears, we recommend prudent avoidance of phthalate containing plastics for foods or beverages. Mr. Kristof pointed out that "These are ubiquitous in modern life ... -- and many scientists have linked them to everything from sexual deformities in babies to obesity and diabetes." Also see Endocrine disruptors.

Conflicting Opinions and Difficulty of Research About Chemical Contaminants in Drinking Water

OPINION: One can cite at various reasons why readers will encounter varying opinions about the actual level of risk from various environmental contaminants:

• Conflicting interests: Some parties have conflicts of interest, financial concerns, or a wish to avoid potential litigation that can arise from admitting even the smallest level of risk from environmental contaminants. Follow the money trail as part of your assessment of credibility. See Kristof's citation of the viewpoint of the American Chemical Council and the chemical industry.
• Difficulty of setting chemical contaminant exposure standards: because endocrine disrupters may have very significant medical effects only during a narrow time window (such as at specific steps of sex determination of a developing ovum), and because these effects may occur when only a few molecules of the problem chemical are present and affecting the cells involved, the exposure levels that appear to be of potentially great concern may be so extremely low as to far exceed any contemporary standard as well as below the levels at which industry is able to control. These effects have been discussed by Kristof, Colborn et als, and in the 1960's by Carson (as well as hundreds of researchers, physicians, and other experts.
• Subtlety and time duration before harmful effects are manifest: as documented in the texts we've cited, some physical effects in the humans or animals affected are subtle, perhaps not visible at all (DES sons and daughters for example), and while they occur at the time of gestation and development of the fetus of the human or animal involved, the actual health or reproductive impact may not be obvious for decades. (For example lowered sperm counts but not yet crossing the threshold at which a species cannot reproduce).
• Consumer fear of environmental hazards can sometimes be irrational or excessive, leading to inappropriate costs for the consumer or for industry. People are often confused about the absolute level of risk of some hazards and have difficulty comparing and responding appropriately to actual risk levels from different hazards (a client who smoked and does not wear her seat belt while in an automobile, but who was frightened of electromagnetic fields). See What is Enviro-Scare for details.
  

US EPA List of Drinking Water Contaminants

Original Source: http://www.epa.gov/safewater/contaminants/index.html

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Microorganisms in Drinking Water

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Disinfection Byproducts Found in Drinking Water

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Disinfectants found in Drinking Water

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Inorganic Chemicals found in Drinking Water

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Organic Chemicals found in Drinking Water

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Radionuclides found in Drinking Water

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Notes

¹ Definitions - US EPA drinking water standards and contaminant levels:
Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to MCLGs as feasible using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards.
Maximum Contaminant Level Goal (MCLG) - The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals.
Maximum Residual Disinfectant Level (MRDL) - The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.
Maximum Residual Disinfectant Level Goal (MRDLG) - The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.
Treatment Technique - A required process intended to reduce the level of a contaminant in drinking water.

² Units are in milligrams per liter (mg/L) unless otherwise noted. Milligrams per liter are equivalent to parts per million.

³ EPA's surface water treatment rules require systems using surface water or ground water under the direct influence of surface water to (1) disinfect their water, and (2) filter their water or meet criteria for avoiding filtration so that the following contaminants are controlled at the following levels:

• Cryptosporidium: (as of1/1/02 for systems serving >10,000 and 1/14/05 for systems serving <10,000) 99% removal.
• Giardia lamblia: 99.9% removal/inactivation
• Viruses: 99.99% removal/inactivation
• Legionella: No limit, but EPA believes that if Giardia and viruses are removed/inactivated, Legionella will also be controlled.
• Turbidity: At no time can turbidity (cloudiness of water) go above 5 nephelolometric turbidity units (NTU); systems that filter must ensure that the turbidity go no higher than 1 NTU (0.5 NTU for conventional or direct filtration) in at least 95% of the daily samples in any month. As of January 1, 2002, turbidity may never exceed 1 NTU, and must not exceed 0.3 NTU in 95% of daily samples in any month.
• HPC: No more than 500 bacterial colonies per milliliter.
• Long Term 1 Enhanced Surface Water Treatment (Effective Date: January 14, 2005); Surface water systems or (GWUDI) systems serving fewer than 10,000 people must comply with the applicable Long Term 1 Enhanced Surface Water Treatment Rule provisions (e.g. turbidity standards, individual filter monitoring, Cryptosporidium removal requirements, updated watershed control requirements for unfiltered systems).
• Long Term 2 Enhanced Surface Water Treatment Rule (Effective Date: January 4, 2006) - Surface water systems or GWUDI systems must comply with the additional treatment for Cryptosporidium specified in this rule based on their Cryptosporidium bin classification calculated after the completion of source water monitoring.
• Filter Backwash Recycling; The Filter Backwash Recycling Rule requires systems that recycle to return specific recycle flows through all processes of the system's existing conventional or direct filtration system or at an alternate location approved by the state.
  

⁴ more than 5.0% samples total coliform-positive in a month. (For water systems that collect fewer than 40 routine samples per month, no more than one sample can be total coliform-positive per month.) Every sample that has total coliform must be analyzed for either fecal coliforms or E. coli if two consecutive TC-positive samples, and one is also positive for E.coli fecal coliforms, system has an acute MCL violation.

⁵ Fecal coliform and E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Disease-causing microbes (pathogens) in these wastes can cause diarrhea, cramps, nausea, headaches, or other symptoms. These pathogens may pose a special health risk for infants, young children, and people with severely compromised immune systems.

⁶ Although there is no collective MCLG for this contaminant group, there are individual MCLGs for some of the individual contaminants:

• Trihalomethanes: bromodichloromethane (zero); bromoform (zero); dibromochloromethane (0.06 mg/L): chloroform (0.07mg/L).
• Haloacetic acids: dichloroacetic acid (zero); trichloroacetic acid (0.02 mg/L); monochloroacetic acid (0.07 mg/L). Bromoacetic acid and dibromoacetic acid are regulated with this group but have no MCLGs.

⁷ The MCL values are the same in the Stage 2 DBPR as they were in the Stage 1 DBPR, but compliance with the MCL is based on different calculations. Under Stage 1, compliance is based on a running annual average (RAA). Under Stage 2, compliance is based on a locational running annual average (LRAA), where the annual average at each sampling location in the distribution system is used to determine compliance with the MCLs. The LRAA requirement will become effective April 1, 2012 for systems on schedule 1, October 1, 2012 for systems on schedule 2, and October 1, 2013 for all remaining systems.

⁸ Lead and copper are regulated by a Treatment Technique that requires systems to control the corrosiveness of their water. If more than 10% of tap water samples exceed the action level, water systems must take additional steps. For copper, the action level is 1.3 mg/L, and for lead is 0.015 mg/L.

⁹ Each water system must certify, in writing, to the state (using third-party or manufacturer's certification) that when acrylamide and epichlorohydrin are used in drinking water systems, the combination (or product) of dose and monomer level does not exceed the levels specified, as follows:

• Acrylamide = 0.05% dosed at 1 mg/L (or equivalent)
• Epichlorohydrin = 0.01% dosed at 20 mg/L (or equivalent)

National Secondary Drinking Water Regulations

National Secondary Drinking Water Regulations (NSDWRs or secondary standards) are non-enforceable guidelines regulating contaminants that may cause cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color) in drinking water. EPA recommends secondary standards to water systems but does not require systems to comply. However, states may choose to adopt them as enforceable standards.

• National Secondary Drinking Water Regulations - The complete regulations regarding these contaminants available from the Code of Federal Regulations Web Site.
• For more information, read Secondary Drinking Water Regulations: Guidance for Nuisance Chemicals.

List of National Secondary Drinking Water Regulations

Unregulated Contaminants in Drinking Water

This list of contaminants which, at the time of publication, are not subject to any proposed or promulgated national primary drinking water regulation (NPDWR), are known or anticipated to occur in public water systems, and may require regulations under SDWA. For more information check out the list, or vist the Drinking Water Contaminant Candidate List (CCL) web site.

• Drinking Water Contaminant Candidate List 2
• Drinking Water Contaminant Candidate List (CCL) Web Site
• Unregulated Contaminant Monitoring Program (UCM)
• Information on specific unregulated contaminants
  • MTBE (methyl-t-butyl ether) in drinking water

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PLUMBING TOPICS
WATER TESTS, CONTAMINANTS, TREATMENT
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EPA GUIDE to WATER QUALITY
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• "Chemicals and Our Health", Nicholas D. Kristof, New York Times, 16 July 2009, p. 27. This outstanding editorial calls for improvements in public health policy to address phthalates and other environmental contaminants from common chemicals and products in everyday use. - DJ Friedman
• Endocrine Disruptor Exchange, Dr. theo Colborn (also see Our Stolen Future). From that website: The Endocrine Disruption Exchange, Inc. is the only organization that focuses primarily on the human health and environmental problems caused by low-dose and/or ambient exposure to chemicals that interfere with development and function, called endocrine disruptors. ... TEDX's work focuses on the endocrine system, which is the exquisitely balanced system of glands and hormones that regulates such vital functions as body growth, response to stress, sexual development and behavior, production and utilization of insulin, rate of metabolism, intelligence and behavior. Hormones are chemicals such as insulin, thyroxin, estrogen, and testosterone that interact with specific target cells. The interactions occur through a number of mechanisms, the easiest of which to conceptualize is through a lock and key arrangement.
• Health Effects of Chemical Contaminants in Drinking Water, US Environmental Protection Agency,
• Our Stolen Future, Theo Colborn, Dianne Dumanoski, and John Peterson Myers, Plume-Penguin Publishing, 1997, ISBN 0-452-27414-1. This book is a seminal work on endocrine disruptors (chemical contaminants having impact at extremely low levels in the environment).
  Amazon.com Review: By O T (Ontario, BC) - 'Our Stolen Future' is a great introduction to one of the most important scientific discoveries in our time. Having recently completed a thesis project at university on Endocrine Disruptors, I have reviewed hundreds of papers on the subject. This book is a good clear overview of the scientific literature on EDs. The authors are experts - Theo Colborn is largely responsible for creating the field by bringing together diverse researchers so they could see the big picture of their work. Many of the principle investigators are interviewed and quoted at length on the way chemicals participate in and interfere with delicate hormonal systems in animals (including humans). The major accomplishment of the book is to make an easy-to-follow story out of complex research. Many resources are available to help you assess the reliability of this story, and the best thing to do if you have any doubts is read review articles in scientific journals (which are easier to understand than technical papers). The Physicians for Social Responsibility (PSR) have a guidebook for health-care professionals on Endocrine Disruptors, and the US EPA has many reports on the matter. Beware of people or websites who try to 'debunk' this book (or the science behind it) by simply declaring it false, flawed or disproven. There is far too much supporting research for so simple a refutation.
  
• Silent Spring, Rachael Carson, Mariner Books; Anv edition (October 22, 2002), ISBN-13: 978-061824906.
  Amazon.com Review: Silent Spring, released in 1962, offered the first shattering look at widespread ecological degradation and touched off an environmental awareness that still exists. Rachel Carson's book focused on the poisons from insecticides, weed killers, and other common products as well as the use of sprays in agriculture, a practice that led to dangerous chemicals to the food source. Carson argued that those chemicals were more dangerous than radiation and that for the first time in history, humans were exposed to chemicals that stayed in their systems from birth to death. Presented with thorough documentation, the book opened more than a few eyes about the dangers of the modern world and stands today as a landmark work.
• US EPA: list of drinking water contaminants: see http://www.epa.gov/safewater/contaminants/index.html
• National Primary Drinking Water Regulations- The complete regulations regarding these contaminants available from the Code of Federal Regulations Website -(United States)
  

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