Drip Drop Water Talk

Separating the sales pitch from science

Category: Technology

All About Lead: Keeping your water safe

All About Lead is part of a series.  To be updated on when the next installment please subscribe to my mailing list.

The ability to have clean drinking water is something most residents in the United States take for granted.  When you’re in a situation where your water isn’t clean, it’s colored, smells weird, whatever, you feel helpless.

This isn’t supposed to happen.  This is America!  Not India.  Not Haiti.  We’re supposed to have clean water.  

It’s hard to see contaminants in water with our eyes; things like lead and cryptosporidium aren’t visible to the naked eye.  

With the on-going crisis in Flint, Michigan, lead is a hot topic these days.  There is a lot of information out there about the problem, but very little information about the actions people who are living with lead water can take to protect themselves.

In this three-part series I’m going to address the history of lead in plumbing distribution, the science behind why Flint is now full of lead, and what actions people can take to remove lead from their water.  

Let’s get started.

 

The History of Lead in Plumbing

The History of Lead in Plumbing

Most of us know that lead is bad so it’s hard to fathom the possibility of there being lead in the water.  In fact, lead is one of the best studied toxic-substances and we know more about the negative health effects than almost any other chemical.  This abundance of information however is unfortunately due to lead’s predominate use throughout history starting in the Roman Empire and extending through the 1990s.  

In Plumbo Nos

The Roman Empire is credited with being the first regime to mass-distribute lead due to their massive mining operations.  Lead itself does not occur in an elemental state but is a by-product of silver and gold mining.  It is readily available, easy malleable, is resistant to corrosion, and is easy to melt at low temperatures making it an ideal material for creating products out of.  

The Romans used lead extensively.  The used it to create plates and silverware, cooking utensils, urns for wine, makeup, and indoor plumbing.  In fact, the word plumbing itself is derived from Latin.

Plumbum.

That’s Latin for lead.  

Plumbum.

Fond of bathing, the Romans constructed great aqueducts to transport water from miles away to baths and recreation centers.  They were the original plumbers, lead workers who were responsible for measuring and laying out pipe, soldering, installing, and repairing the infrastructure that moved water around cities such as Rome and Pompeii.  

It should be noted that not all plumbing was created out of lead, some were created using terra cotta pipes.

With the decline in the Roman Empire so came the decline in plumbing.  Bath houses came to be viewed as places of debauchery and cleanliness decreased in value.  

It wasn’t until the mid-1800s when diseases like typhoid and Cholera were rampant that the link between bacteria and disease was discovered by Louis Pasteur.  Plumbing, especially to keep clean water isolated from wastewater, became of increasing importance. 

The New World and Lead

Almost as soon as the first colonists settled in the United States the mining and smelting of lead began.  Lead was originally sought out for its use in ammunition and by 1621 the metal was being mined and forged in Virginia but it wouldn’t be until later that lead would be used to transport water.

Early water distribution systems were created using bored-out logs, usually from hemlock or elm trees.  In 1652 Boston unveiled the country’s first water distribution system using these hollowed out trees in order to provide water for firefighting and domestic use.  

There were several problems with using wooden pipes however.  Uneven ground would cause the pipes to sag, creating pockets of stagnant water that developed a woody taste over time.  As cities expanded more pressure was needed to move the water farther and farther and this would cause the wooden pipes to split.  

As wooden pipes ceased to be useful, a switch to iron was made.  The city of Philadelphia became a global leader in plumbing when it became the first city to distribute water using entirely cast iron pipes in 1804.  Other cities such as Chicago, New York, and Boston followed suit.  

As plumbing knowledge evolved, so did the ease of bringing water inside homes.  Instead of getting water from a pump in the street one could get water from a faucet inside your house.

 Designing piping to move water around cities was fairly easy and straightforward but when it came to connecting buildings to water mains things became more complex.  There were a lot of pipes and conduits in the streets so piping that was flexible was highly desirable.  

The connections from water mains to buildings are known as service lines and creating these pipes out of lead became the most practical solution for engineers.

Lead service line location

Lead in the 20th Century

By 1900, of the 50 largest cities in the United States all but six or seven of them has installed lead piping.  New York, Chicago, Philadelphia, Saint Louis and Boston all used lead services to varying degrees.  

Many local building codes mandated that lead service pipes be used for constructing service lines.  Lead is more durable to corrosion than iron piping and many of the lead pipes that were being used in 1900 are still in use today.  

A committee on service pipes submitted a preliminary report to Engineering News, a journal of civil engineering and construction that was issued weekly, on the use of lead service pipes in 1916.  The report stated:

Lead is in many respects the most satisfactory material to use for service pipes. Its pliability and its comparative freedom from corrosive action make it almost ideal from a mechanical standpoint. The cost of lead pipe of sufficient thickness safely to withstand the pressure is more than the cost of many other materials used for service, but in a paved street the greater duration of life probably more than compensates for the extra cost, and in places where the streets are occupied by other pipes and conduits the ease of getting over and under these obstructions with a flexible pipe is a great advantage.

The article continues:

The most serious objection to the use of lead pipe for services is the possibility that the water may dissolve enough lead from the pipe to cause lead poisoning. It is certain that many cases of lead poisoning have been caused by the use of lead services.  On the other hand, lead has always been used for services in most of the large places without any unfavorable effects.

Engineers knew lead pipes were bad and could poison people but didn’t understand why in some areas people became poisoned and in others people were fine.

It seems to be practically impossible to determine definitely in advance what the effect of any water on lead pipe will be, as the laboratory results fail in many cases to show the action which will occur in actual practice.  Tests of service pipes in use for a considerable period are the only safe guides.

This highlights a key point in the use of lead pipes.  

Not all lead pipes pose a health risk.  

Not all lead pipes pose a health risk.

If the water chemistry is good, with a pH that’s close to neutral and not overly corrosive water, then lead pipes can be perfectly safe.  

In the 1930s copper pipes or galvanized steel pipes began to replace most of the lead pipes in residential plumbing.  Solder, a material that’s used to join together metals like copper pipe, still contained lead until it was banned for plumbing applications in the 1980s.  

The importance of lead dissolved from lead service lines has received little attention until now because over time oxidation created a protective coating along the interior of the lead pipes.  This limited the amount of lead that would leach into the drinking water and could be ingested.  

This brings us to today, where residents in Flint, Michigan, have been struggling with lead contaminated water since the summer of 2014.  


In a couple weeks I’ll be sharing the science behind how Flint became full of lead.  To be one of the first to know when the next installment is available please subscribe to my mailing list. 

Reverse Osmosis and Bacteria

Do reverse osmosis filters remove bacteria-

Q: Do reverse osmosis filters remove bacteria?  How?

A: Yes, bacteria will be removed via reverse osmosis due to size exclusion (i.e. the bacteria are larger than the pores in the reverse osmosis membrane so they can’t pass through).  However there can be defects in the membranes which allow the bacteria to pass through.  I’ve also seen it hypothesized that the bacteria will move around the o-ring which typically seals the reverse osmosis into place within its housing.  Secondary contamination, where bacteria will move up the pure water stream and attach to the membrane, is also a possibility.  This is why while bacteria can be removed via reverse osmosis, these systems are rarely certified to be microbiological purifiers.

 

Find this question and others I’ve answered on Quora.  

Treating for Pharmaceuticals and Personal Care Products

pharmaceuticals

The detection of new contaminants such as pharmaceuticals and personal care products in drinking water has opened up a new opportunity in the water treatment world to innovate and design new technologies that can address these contaminants.  In order to address concerns about the performance and claims used by marketers for treating water in a household, the National Sanitation Foundation (NSF) created a series of American National Standards (ANSI) to confirm the claims are true, the system doesn’t impart anything harmful into the water, and that the product labeling isn’t misleading.

A new standard NSF/ANSI 401: Emerging Contaminants/Incidental Compounds has been developed to verify the ability of a drinking water treatment device to reduce 15 emerging contaminants such as DEET, Ibuprofen, Estrone, and Bisphenol A.  Most contaminants certified by the NSF are either classified as “health effects”, which are contaminants known to adversely affect health when present in water, or as “aesthetic effects”, which are contaminants known to adversely affect the taste, odor, or appearance of water.  Emerging contaminants however are a new category created to address the concerns over contaminants whose health effects have not yet been established.  The contaminants used to challenge water treatment devices under the new standard include prescription/over-the-counter drugs, herbicides and pesticides, and chemicals used as flame retardants and detergents.

At the time of this post (12/1/2015), 22 manufacturers have certified 156 different products to this standard.  The products which have been certified include point-of-entry (POE) and point-of-use (POU) devices such as refrigerator filters, counter top units, faucet mount filters, and under sink units,  The list of products which are currently NSF 401 certified can be found on NSF’s product and service listing’s page.

New Membrane Material Developed which may Compete with Current Desalination Membranes

MoS2 membrane

Move over graphene, there is a new membrane material in town!

Researchers at the University of Illinois at Urbana-Champaign have developed a new membrane material for water treatment.  This material is a nanometer-thick sheet of molybdenum disulfide (MoS2) which is riddled with tiny holes ranging from 1 to 10 nm in diameter called nanopores.  Today the market is full of reverse osmosis (RO) membranes which typically have a pore size of 0.1 nm but are thick due to their polymeric material.  This thickness has a direct relationship on the amount of energy it takes to push water through the membrane and current advances to increase the recovery rate of water through an RO membrane are limited to the orientation of membrane leaves (individual sheets of membrane through which water passes).  By creating a thinner membrane, less energy is required to filter water and lower operating costs are feasible.  Despite its thinness MoS2 is mechanically robust with an effective Young’s modulus of 270±100 GPa (about that of steel), which is not completely surprising considering that molybdenum is frequently used for making high strength steel alloys and superalloys.

In order to determine the effectiveness of the MoS2 membrane for water permeation, it was compared against conventional water treatment membranes: MFI-type zeolite, seawater RO, brackish water RO, nanofiltration, high-flux RO, and including graphene.  The permeation rate was found to be two to five orders of magnitude higher than conventional membranes and 70% greater than graphene.  This increased transport of water was attributed to the architecture of the pores within the membrane.  Molybdenum is located in the center of the membrane which attracts water, and the sulfur on the other side which pushes the water away.  Ion rejection rates of the MoS2 membrane were on par with that of seawater RO membranes and graphene.  Further testing is expected to look at fouling of the MoS2 membrane.

The Drinkable Book

Problems with drinking water and sanitation in many developing countries go hand in hand.  Earlier this year Unicef and the World Health Organization published a report lauding the accomplishments made to deliver safe drinking water to people, an effort which has been undermined by a failure to meet global targets for improved sanitation.

To help combat this the organization WaterisLife is working in conjunction with Dr. Theresa Dankovich to develop The Drinkable Book, an instructional manual for how and why to clean drinking water as well as acting as a water filter.  The pages of this book are made up of cellulose paper impregnated with with silver nanoparticles.  The silver slowly leaches out of the paper in tiny amounts and is toxic to living microorganisms providing a disinfection benefit capable of granting the user access to safe drinking water.

By combining the pages of the book with an educational component, The Drinkable Book has the power to potentially help address the issue of poor sanitation while also providing safe drinking water.

New Trend: Bespoke Water

With the growing trend of buying more local, hand made (or both!) consumer goods, it’s probably not that hard to imagine a world where it’s possible to buy artisan water.

This video produced by filmmaker Paul Riccio pokes fun at the growing desirability of handmade products.

A short look at the Timmy Brothers, Brooklyn–based makers of bespoke drinking water.

Bill and Terry Timmy are introducing handcrafted water to the world with an almost pathological attention to craftsmanship and a thirst for helping people become less thirsty.

The Timmy Brothers. They make water.

While this video is intended as satire, it’s not that hard to imagine a world where water is crafted to reflect water from a sacred or sentimental area. Today many bottled water manufacturers will strip the water of existing minerals through processes such as reverse osmosis and distillation, then add minerals back into the water.  This ensures that the water produced with two vastly different incoming water sources will taste the same.

Water from various regions in the world will taste significantly different.  Water from Iceland for example is mostly glacial runoff with very little minerals present in the water.  Water from underground aquifers in the United States on the other hand will typically contain much higher amounts of minerals due to the dissolution of limestone rock over thousands of years.

Capitalizing on this information is Ray’s and Stark Bar in Los Angeles, California.  This gourmet farm-to-table restaurant employs a water sommelier to help select the perfect water to accompany your meal. Here a water menu details the taste profiles of bottled water from 20 different locations around the world, rating the water from sweet to salty as well as smooth to complex.

Instead of buying bottled water harvested from a specific region, it’s likely that in a few years it will be possible to buy a bottle of faux-Iceland water, water designed to taste exactly like that which you can only obtain in Iceland.  Water could be purified then remineralized to mimic water from other areas like Norway (Voss) or Greenland (Berg) to name a couple.  This would bring down the cost of water that was previously expensive to import while providing specialty crafted water.

The Top 5 Drinking Water Contaminants and How to Remove Them

Now that you know how to find out what is in your water, here are the the top five most common contaminants in drinking water.

1) Hard water

eagle-water-treatment-hard-water
Having hard water isn’t bad from a health perspective but it will wreak havoc on your appliances that use hot water. Hard water is comprised of calcium and magnesium which have dissolved into groundwater over the course of centuries. Having a low level of hardness is fine but once you start getting over 12 grains per gallon (205 parts per million) you may want to consider installing a water softener.

2) Iron

iron-water-stains culligan Tulsa
Iron is another common contaminant frequently present in drinking water.  Similar to hardness, iron is present in water due to the dissolution of minerals over the course of centuries. Again, having iron in your water is only bad from an aesthic effect. Iron exists in water in the ferrous form but once it comes into contact with oxygen iron changes form into ferric and becomes the bright red color most are familiar with.  On the bright side, most who suffer from high levels of iron also have very hard water and the water softener will also work to remove iron. Iron is a secondary contaminant for the EPA, who recommends that you keep your iron level below 0.3 ppm for optimum tasting water.

3) Lead

lead plumbing - certified home inspection

This contaminant is most frequently found in the drinking water for those who live in older cities such as Chicago and Washington DC.  Lead is introduced into the drinking water through the distribution system, picking up lead from pipes, solder, and fittings that all were once made with lead. Now the Safe Drinking Water Act (SDWA) requires that products like fittings must have a weighted average of less than 0.25% lead.  The only way to know if your water has lead in it is to test the water and the most accurate way to accomplish this is to have your water analysed by a certified laboratory.  There is no safe level of lead in water, but there is an EPA action level of 15 parts per billion which means that once that level is reached the water authority must take action to replace 7% of the portion of lead service lines they control each year. If you have lead in your water an undersink reverse osmosis system is going to provide the most benefit to you.

4) Chlorine and chloramines

chlorine tabs - grand slam pools

Technically these are two separate contaminants but they act in many of the same ways.  In order to protect drinking water from microbiological contamination the drinking water treatment plant will frequently add a disinfectant such as chlorine or chloramine to the water.  This leads to drinking water typically having a concentration between 0.2 to 1 parts per million of chlorine.  The EPA has a maximum residual disinfectant level of 4 parts per million as an annual average.  If your water has a chlorine taste or odor, a simple carbon filtration system (such as a Brita filter) will be most effective at creating a more aesthetically pleasing water.

5) Disinfection Byproducts

water help disinfection by products

When water has high concentrations of total organic compounds (TOC) or other naturally-occurring matter in the water, disinfectants such as chlorine and chloramine themselves can react to form byproducts which may pose health risks.  It is widely understood that chlorination will produce chlorinated and brominated disinfection byproducts (DBPs) with potential carcinogenic effects on humans.  While there are 80+ known disinfection byproducts, the EPA only currently regulates 11 of them.  Other DBPs may be present in water at levels too low for detection, or the health effects may not be known.  Again, a simple carbon filtration system (such as a Brita filter) is useful for removing these organics from the water.

(Photo credits: Eagle Water, Culligan Tulsa, Plumbing Problems Today, Grand Slam Pools, and Water Help)

What’s in my Brita filter?

Brita Filter 3 pack 2015-07-15 v2

Brita filters have become incredibly popular in the United States.  Available as faucet mounted filters or as cartridge filters for pitchers, these filters are an easy means of removing aesthetic contaminants from drinking water.  Two primary technologies exist inside of the filter: granular activated carbon and ion exchange resin.

The granular activated carbon (GAC) is derived from coconut shells and its primary purpose is to remove any taste and odor from the water.  Most people do not find the chlorine and chloramines that are added to drinking water by the water treatment plants to control the growth of microorganisms very palatable.  GAC is able to easily remove these contaminants as well as any disinfection by-products that are produced when the chlorine comes into contact with organic matter in the water.  As coconut carbon has a high surface area due to its microporous structure, the GAC is able to adsorb a high amount of contaminants from water.  Once all the adsorption sites are taken up by organics, the GAC will cease to function as intended.

The ion exchange (IX) resin is mixed into the GAC in order to remove heavy metals such as copper, cadmium, mercury, and lead.  These metals have a positive charge in water and are naturally attracted to the cation IX resin.  In other applications using IX such as water softening, the resin is recharged and is able to be reused over and over.  The Brita filter is designed to be disposable, and the IX resin inside is not meant to be recharged.  Once all the exchange sites are occupied by positively charged ions, the IX resin will also cease to work properly.

The Brita filters are a decent means of producing good tasting drinking water.  However, their capacity is limited and it’s one of the most expensive methods of polishing drinking water.  At its current price of $14.88 for a set of three replacement filters, each gallon of water through the filter will cost $0.12.  This is higher than the cost of using other types of filters (such as countertop or undersink) but still much cheaper than buying bottled water.

(Pictured at top: Brita filter 3 pack on Amazon, uploaded by Brita)

Powered by WordPress & Theme by Anders Norén