Water Quality InformationWritten By Actual Experts

Stephanie Angione, Ph.D.  |  Scientific Contributor

What Are Polychlorinated Biphenyls (PCBs)?

Polychlorinated Biphenyls (PCBs) are a class of industrial chemical that were widely manufactured in the US from the 1930s through the 1970s for use in electric equipment such as capacitors and transformers, and also as heat transfer fluids, plasticizers, adhesives, fire retardants, inks, lubricants, cutting oils, pesticide extenders, and in carbonless copy paper.
 
While PCB production slowed in the 1960s and was banned completely in the US in 1979, they are still found in industrial applications due to their chemical longevity. The US congressional ban was enacted due to the fact that PCBs are persistent organic pollutants, which create long lasting environmental toxicity and cause harmful health effects. Products that contain PCBs include old fluorescent lighting fixtures, PCB capacitors in old electrical appliances (pre-1978) and certain hydraulic fluids.
 
Nearly 2 million tons of PCBs have been produced since 1929, 10% of which persists in the environment today. Generally, environmental concentrations of PCBs are low, but due to their chemical inertness they are largely resistant to chemical breakdown or thermal destruction, and thus accumulate in the environment. Additionally, PCBs are highly fat soluble, resulting in the build up of PCBs in animal fat, resulting in higher concentrations of PCBs in top food chain consumers (e.g. predatory fish, large mammals, humans).
 

Where Are PCBs Found In The Environment?

Polychlorinated Biphenyls accumulate primarily in water sources, organic portions of surface soil, and in living organisms.
 

Water

Surface water that is contaminated with PCB waste generally has high levels of PCBs in sediment, as the PCBs attach to organic matter. PCBs can be slowly released from the sediment into the water and evaporate into the air, especially at higher temperatures.

Air

PCBs have been detected throughout the atmosphere, and can be transported globally through air. Concentrations of PCBs in the air are generally the lowest in rural areas and highest in large cites. Areas that are close to bodies of water that were highly contaminated with PCBs from industrial waste (e.g. Lake Michigan, Hudson River) can have higher air concentrations, due to evaporation of PCBs into the air over time.  

Living Organisms

PCBs accumulate in living organisms via bioaccumulation, or uptake from the environment, as well as biomagnification, from consumption along the food chain. Bioaccumulation is typically highest in aquatic species, with bottom feeding species having the highest levels of PCBs due to accumulation in sediment.  PCBs biomagnify up the food chain, as bottom feeders like shellfish are eaten by other species, and thus the greatest levels are found in large predatory fish. This process can also occur on land, as PCB contamination in soil is transferred up the food chain to insects, birds and mammals. Thus, one of the largest sources of PCB exposure and accumulation in humans is from food, specifically meat and fish.

How Do PCBs Impact Humans?

While PCBs have been classified as probable human carcinogens, there is no evidence that the low levels of PCBs in the environment cause cancer. Exposure to high levels of PCBs have primarily occurred through workplace exposure in people who work in plants that manufacture the chemicals. Studies of workers exposed to high PCB levels have shown association with certain types of cancer. These high levels of exposure have also been known to cause liver damage, skin lesions called chloracne, and respiratory problems.

Exposure to PCBs during pregnancy can result in developmental and behavioral deficits in newborns. Additionally, there is evidence that reproductive function can be disrupted due to PCB exposure. Women of childbearing age, or those who are pregnant or nursing should be aware of fish and shellfish advisories to limit consumption of PCB contaminated fish.
There are additional studies that suggest PCB exposure can cause health effects including thyroid dysfunction, liver dysfunction, as well as adverse cardiovascular, gastrointestinal, immune, musculoskeletal, and neurological effects.

How Are PCBs Regulated & Monitored In The US?

With so many sources of PCB exposure from food and water sources, the US government has guidelines on the amount of allowable environmental PCB contamination for each.  

Food

The FDA enforces a tolerance level in fish of 2 ppm, and overall 0.2 -3.0 ppm for all foods. PCBs in paper food packaging are limited to 10 ppm.
 
If fishing recreationally and you plan to eat your catch, check if any local fish consumption guidelines exist for your area. The EPA maintains a national database of fish and shellfish advisories issued by each state. These consumption advisories may recommend limiting the amount of a certain fish consumed, or from specific waters or water sources. As of 2011, five areas have advisories for PCBs in freshwater sources (Missouri, Minnesota, Maryland, Indiana, and District of Columbia) and nine states (Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, and Rhode Island) have PCB advisories for coastal waters.

Drinking Water

Under the Clean Water Act, industrial discharge of Polychlorinated Biphenyls in water is prohibited. The goal is to reach zero contamination in drinking water, but the enforceable maximum level is 0.0005 part per million (ppm).  Additionally, industries are required to report spills or accidental releases to the EPA. 

Routine monitoring of PCB levels in drinking water require the water supplier to maintain the limit enforced by the EPA and must make the data regarding water quality and contaminants public. Every year, the EPA requires water suppliers nationwide to provide a Consumer Confidence Report (CCR), which will include information about water treatment and any known contaminants. These reports are available on the EPA website and should be available on your water company’s website. Additionally, the supplier is required to alert customers of increased levels of PCB contamination as soon as possible.
 
If you get water from a household well, the local health department should have information about ground water quality and contaminants of concern, but it is often a good idea to have your water tested by a certified laboratory if you are worried about PCB (or other) contaminants. The EPA’s Safe Drinking Water Hotline (800-426-4791) can provide additional resources in your local area.

How Can I Remove PCBs From My Water?

If your water has high levels of PCBs in it,  the water should also not be used to drink, prepare or cook food,  or given to pets for consumption without first treating it.  Fortunately, PCBs are effectively removed from water by filters that use activated carbon as part of their active filtration media blend.
 
Hydroviv makes it our business to help you better understand your water.  As always, feel free to take advantage of our “help no matter what” approach to technical support!  Our water nerds will work to answer your questions, even if you have no intention of purchasing one of our water filters.  Reach out by dropping us an email (hello@hydroviv.com) or through our live chat. You can also find us on Twitter or Facebook!

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Eric Roy, Ph.D.  |  Scientific Founder  

Disinfection byproducts are a class of contaminants that have been detected in drinking water throughout the country. Unlike things like arsenic and lead, most people are not familiar with disinfection byproducts. The goal of this article is to dive deep into the chemistry, history and policy surrounding disinfection byproducts.

What Are Disinfection Byproducts?

Water disinfection was an extremely successful public health accomplishment. It's the main reason why waterborne illnesses are not a persistent threat in United States tap water. However, adding chlorine-based disinfectants to water can have harmful unintended consequences, one of which being that they can react with other things found in tap water (e.g. organic matter) and form a class of halogenated chemicals known as "disinfection byproducts." Disinfection byproducts are generally regarded as an "emerging contaminant", because despite having identified more than 600 different disinfection byproducts, roughly 50% are still unaccounted for.

Why Do We Care About Disinfection Byproducts?​

Many halogenated organic compounds are known carcinogens in humans (e.g. dioxin, DDT, Carbon Tetrachloride, PCBs), so they rightfully receive quite a bit of scrutiny when detected in tap water. While some disinfection byproducts in water have almost no toxicity, others have been associated with cancer, reproductive problems, and developmental issues in laboratory animals. Some population-scale epidemiology studies have also found an association between chlorinated tap water and these same problems in humans. Because more than 200 million people in the US use chlorinated tap water as the primary drinking water source, it’s something worth taking a very close look at.

How Are Disinfection Byproducts Regulated?

History Of Disinfection Byproduct Regulation

In 1974, trihalomethanes were detected in drinking water and linked to chlorine based disinfectants that were added to municipal tap water. Around the same time, the National Cancer Institute classified trihalomethanes as human carcinogens, and as a result, EPA established a drinking water standard for trihalomethanes in 1979. As more was learned about disinfection byproducts in water, the US EPA and other government, public health, and industry stakeholders began negotiating 2 stages of more comprehensive regulations in the mid-1990s. Stage 1, which was published in 1998 for 2002 compliance, ruled that haloacetic acids must also be monitored in tap water, in addition to trihalomethanes. The Stage 1 Rule also mandated that these chemicals be monitored throughout the entire water distribution system, not just a few predefined sampling locations. The results of the increased monitoring revealed that more municipalities were non-compliant than initially expected. Stage 2 of the regulation was published in 2006 (for 2012-2016 compliance), and further refined the sample collection strategy with the goal of protecting the public. In the future, most people expect that the regulations will continue to tighten as more about the long term effects of these chemicals becomes better understood, and the technologies that reduce their concentrations at the municipal level improve.

How To Know If A Municipality's Tap Water Has High Levels of Disinfection Byproducts

Overall, disinfectant byproduct concentrations are difficult to predict, because many factors influence their formation including: concentration of organic matter, chemical composition of the precursor materials, pH, temperature, type of disinfectant used, and the concentration of disinfectant. However, because monitoring for trihalomethanes and haloacetic acids are mandated by the EPA, the average concentrations found in the water supply must be made available to the public in annual drinking water reports. 
​
Within a given municipal water system, different physical locations can have higher disinfection byproduct concentrations than others, based on where the home or business is located. This is because the longer it takes for the water to reach the home, the more opportunity there is for disinfection byproducts to form. Therefore, locations close to fast flowing water mains often have lower levels of disinfection byproducts than homes found at the periphery and low flow areas of the water distribution network. Additionally, disinfection byproduct concentrations can continue to rise in residential pipes/water tanks if the water remains stagnant for extended periods of time (e.g. during the work day, overnight). In fact, most municipalities recommend letting water run for 1-10 minutes before using it for drinking or cooking so pipes can flush out. (Obviously, nobody does this….)

What Are The Primary Ways That People Are Exposed To Disinfection Byproducts In The Home?

​In the home, most people primarily use chlorinated tap water to drink, bathe, wash dishes, etc. A few studies have looked at the relative importance of the various exposure pathways, and found that showering contributed heavily to blood levels of trihalomethanes. While this may be initially surprising, it does make sense, because trihalomethanes can be volatilized in hot water and subsequently inhaled. During a shower, disinfection byproducts can also enter the body through absorption through the skin. Because most people come in contact with over 17 gallons of water in an “average” 8 minute shower, but drink less than a half-gallon of water each day, it makes sense that showering can be a major exposure path. Granted, this study only looked at the exposure route for one class of disinfection byproducts, but it does reveal that exposure pathways in addition to drinking, and is a great discovery to build upon with follow-up studies. 

What Can Individuals Do To Reduce Their Exposure To Disinfection Byproducts?

​To be clear, the discovery of DBP exposure through showering does NOT mean that you should be afraid of showering, rather it's a piece of information that may be considered in any changes to the regulation. As frustrating as it may be to people "looking for answers," the reality is... good science is a slow process... and modifications to regulations are often even slower! While regulatory agencies and municipalities are taking steps toward reducing DBPs in water (by pre-oxidizing or filtering out organic precursors), the most effective way for consumers to reduce their exposure today is by filtering their water at the point of use, and/or by flushing stagnant water out of the pipes by letting it run for a few minutes before using it.

Sources:

1. https://www.epa.gov/ (and sources therein)  Accessed on 12/25/2015
2. https://www.cdc.gov/safewater/publications_pages/thm.pdf
3. Backer, LC, et al., 2000
4. Richardson et al., 2007

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Eric Roy, Ph.D.  |  Scientific Founder

***11/20/2019: Note from Eric. It’s been recently brought to my attention that the July 16, 2015 date on this article may have been incorrect, and that the correct publication date is October 14, 2015. We’ve changed the date listed on the article to reflect this.***

I wanted to take a make our readers aware of a largely unreported disaster that is underway in Flint, Michigan. The residents of Flint, MI are being poisoned by lead in their tap water because the municipality messed up... big time. In this post, I'll focus on the science behind lead contamination, the facts (as we know them) of what happened in Flint, and touch upon another incident in recent history where a similar thing happened.

​All water has impurities in it. Most impurities are harmless (e.g. dissolved oxygen, minerals), some are harmful (e.g. lead, arsenic, mercury).

Impurities typically enter tap water in 3 ways:

1. Some are found in the source water (e.g. naturally occurring minerals)
2. Some are deliberately added as part of the treatment process (e.g. chlorine)
3. Some are picked up along the way from the treatment facility to the tap. 

Lead is almost never found in source water at dangerous levels, and nobody deliberately adds lead to their water supply, because it's toxic. Lead can, however, be be introduced to tap water as it flows from the treatment facility to the tap.

How is Flint’s drinking water picking up lead in transit?

It’s pretty straightforward: Nearly all homes with plumbing installed before the 1986 use lead-containing solder to join copper pipes. Lead can also be found in residential plumbing fixtures manufactured before 1998. Additionally, some older homes use lead service line pipes to connect water mains to homes. Proper water quality testing (e.g. pH, chloride, toxic metals) and corrosion control practices (e.g. monitoring chloride levels, maintaining a slightly alkaline pH, adding corrosion inhibitors) are what keep residents with older plumbing and service connections safe from lead contamination. This is not unique to Flint. Unfortunately, it's not always done correctly, and residents suffer.

In Flint, as well as other places where high lead levels have leached into municipal tap water (e.g. Washington, DC in the early 2000’s), monitoring and corrosion control measures failed, which allowed lead to dissolve from pipes/fittings/fixtures and poison the residents.

What changed in Flint to cause the lead contamination problem?

In 2014, Flint stopped buying its tap water from Detroit (which has proper corrosion control measures in place), and began collecting their water from the Flint River as part of a plan to switch to a different water supply. During the changeover process, the municipality failed to implement effective corrosion control measures, and the corrosive water allowed lead to leach from lead-containing plumbing. Because proper water quality monitoring procedures were not in place, the Lead problem was not widely discovered until recently.

What Now?

Flint has announced that it will resume buying water from Detroit, which gets its raw water from Lake Huron and has proper monitoring and corrosion control measures in place. This is a great first step, but it's important that Flint keeps monitoring their water for lead, because the pipes can continue to leach lead while the corrosion control measures build up the protective layer on the inside of the pipes. The length of time this takes will depend on the degree of corrosion, and whether or not Flint's water will have "boosters" of the anti corrosion chemicals.

Until lead levels drop, residents are being urged to use a quality water filtration system that effectively removes lead. Contrary to some of the information out on the internet... boiling water before use does NOT decrease the amount of lead. It is critical that Flint residents use a filter that effectively removes lead, and also changes the cartridges on a regular basis. I would expect that the filtration capacity (in gallons) for lead would be much lower than the manufacturer claims, because the gallon capacity ratings were determined using water with much lower lead concentrations than what is currently being measured in Flint.

Even though there is a plan moving forward, this type of incident almost certainly caused harm to some residents Flint, and the areas most affected by it were probably homes with older plumbing. Even though lead contamination is odorless and tasteless, it has devastating effects on human health. Since Flint began using the Flint River as a water source, numerous children have tested positive for high levels of lead in blood, and a number of schools have recently shut down water fountains due to high lead levels. When a similar lead contamination issue occurred in Washington DC between 2001-2004, stillbirths shot up during the affected years (Edwards, 2013). As was the case in Washington, DC, the full extent of harm likely will not be realized for several years.

*** Update June 2016: We are getting a lot of questions from Flint residents about what to do now. The message that we want to communicate to people in Flint is that you now have a world leader in Mark Edwards actively working with the city to help fix the problem. There is quite literally no person on earth with more credibility than Dr. Edwards on this topic, and nobody with a better track for helping people who have been affected by this sort of disaster. Please listen to him with open ears. He will not lie to you. There are a lot of far less credible people who are looking to elevate their status by saying things that will resonate with residents. Please do not listen to them. This problem will take longer to fix than it took to create, but understand that you now have the top expert on earth working on the problem.

Sources:​
M. Edwards. Fetal death and reduced birth rates associated with exposure to lead-contaminated drinking water. Environmental Science & Technology. Published online December 9, 2013. doi: 10.1021/es4034952.

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