Lead (Pb) In Your Water?

I get asked a lot of questions about lead in water supplies. Questions like how dangerous is it? Or how much is present in their water? Or where does the lead come from? And what can individuals do to remove lead from their drinking water? Since lead can cause brain damage when ingested, these are all very important questions that need answers. Be careful of the dates in this article. They will vary largely depending on where you live as different jurisdictions banned lead at different times. Another thing to note is that on average drinking water only counts for 20% of American’s lead exposure (according to the EPA) and total exposure is what causes health problems.

Soruce: science.howstuffworks.com

Lead can be very dangerous in water supplies. If consumed in large enough quantities it can cause severe brain damage, kidney damage, anemia and there is some evidence that lead can cause high blood pressure.  Compounded on this brain damage is what happens to the larger community if everyone is drinking lead contaminated water and significant percentage of people are suffering from lead poisoning. Costs for healthcare (monetary or increasing disease) increase significantly with lead exposure and with that a decrease in quality of life.  They younger you are the more lead exposure affects you (including before you are born).  This is because growing children absorb more lead from the food and water they drink. Also because they are smaller, they can hit toxic levels sooner.  Finally, lead has a cumulative effect on the body. Your lifetime exposure determines if there will be any negative health effects.  Some lead will remain in your bloodstream for the rest of your life, and most will end up in your bones.

If you are on a large municipal system there is a good chance the monitor for lead. In Ontario, Canada, the Provincial government forces every municipal system to test for lead twice a year throughout the system. Any sample that exceeds 0.010mg/L will be reported immediately to the local health unit the ministry of environment. The resident will be informed shortly thereafter. If you are curious about lead levels you can find the results in the Annual report for the municipal water system. If you are more proactive you may even be able to volunteer your home as a sampling point for a lead testing. Failing that you can always send a sample to an environmental laboratory.  Calling your municipality will get you the information of what they are doing to control lead.  They have more options available to them than any individual does.

Lead gets into water supplies in three main areas. Into the source water from natural deposits or from lead based pollution. Finally, and by far the most significant source of lead is from plumbing with lead based metal fittings. Many alloys contain lead. Even lead free metal fittings can still contain lead and even buying top quality fittings still poses a lead risk. Any solder made before 1986 likely contains lead, sometime upwards of 50%. If you live in an older home (pre 1930’s) there is a chance that you have a lead service connection and possibly lead plumbing.

Homes less than five years old also can have lead problems because the water has not coated the internal plumbing with scale. Scale is a build up of minerals on the wall of pipes and reservoirs that physically separates the water from any potential lead.

Lead Pipe and Copper Pipe (source: winnipeg.ca)

Lead was used so frequently because it is very easy to form into useful shapes. Shapes like pipes, valves and curves. Lead is very soft, that’s my it can make so many useful shapes easily. Lead on it’s own is often too soft for retaining the shape you want, especially if there is any stress on the metal. However mixing lead with other metals like brass, make the brass easier to work with and give the lead more rigidity. Copper was mixed with lead a lot less often then other soft metals. This is one of the reasons pipes were switched to copper. However fittings are still often made of brass because it is easier to make complex shapes like valves in brass. Remember that even “lead free” brass still has some lead in it.

Because lead is in older solders, flux and metal pipes, most of the lead enters the water while sitting in the household plumbing. Typically overnight when the water sits still in the pipes for at least a few hours. Lead needs time to be absorbed into the water (or leached from the metal). The longer water touches anything with lead in it the more lead enters the water. Lead absorption is also influenced by pH. The lower the pH (more acidic and therefor more corrosive) the greater ability the water has to remove lead from other sources. Raising the pH will help reduce the amount of lead that leaches into your water, it will also encourage scale formation. You can mimic corrosive water by grounding electrical systems to metal plumbing.  Grounding electrical systems to your plumbing is bad for your plumbing and helps lead enter your water.  BUT PLEASE GROUND YOUR ELECTRICAL SYSTEMS SAFELY AND ACCORDING TO CODE.  Temperature also affects lead absorption. The hotter the water the more likely there will be lead in the water and the water’s ability to carry water increases.

Scale Formation In Copper Pipe (estimated 20 years of scale growth) (source: ryan-technology.com

So what can you do about lead in your water? First, get your water tested. Knowing there is a problem is essential because you can’t see, taste or smell lead dissolved in water.
Second, always flush until the water is as cold and stops getting colder. If your home is older than 1930 and you don’t know for sure that your service connection isn’t lead then flush for an additional 15-30 seconds to make sure you are getting water from the street. This flushed water doesn’t have to go to waste. It can be used for non-consumption purposes like washing and gardening.  Flushing may not be a viable option for you if you live in a high rise building as the pipes may be too large for you to flush economically.
Third, never use the hot water tap for consumption purposes. It is better to boil cold water if you need hot water.  Lead affects children and pregnant women significantly more than it does grown ups.  Small amounts of lead that are harmless to a adult, can be highly toxic when introduced to smaller bodies.  You can buy a water filter that is capable of removing lead from water.  If it is not specifically designed to remove lead then there is a good chance that it doesn’t remove much lead at all.  Because lead has been such a big issue in the past, there are a lot of fake and ineffectual “lead” filters out there.  Double check the manufacturers claims with independent information or get the water tested.  Don’t forget to change the filter often otherwise you will expose your water to VERY high levels of lead.

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Disinfection Of Water Using Ultraviolet Radiation

Ultraviolet light is a very popular method of disinfecting water.  UV radiation is part of the electromagnetic spectrum that has incredible properties for the killing of microscopic organisms.  While there are varying degrees UV resistance within microscopic organisms, not one has yet been able to develop a total resistance.  Because UV disinfection systems are not chemical or biological they have an extremely long shelf life.

The Electromagnetic Spectrum with a UV Focus (From: agtuv.com)

There is a wide variety of ultraviolet disinfection systems that range from the size of a pen to large banks of meter long light bulbs and many options in between. UV systems tend to be very simple to install and operate and UV leaves nothing behind and there are no disinfection by-products from its application.  In fact ultraviolet radiation can break down some potentially harmful chemicals like chlorine and chloramine compounds.

Ultraviolet Lamp (from: halmapr.com)

The limitations of UV disinfection are; distance, time, turbidity and electricity.

Proximity is critical for UV disinfection, the water needs to be very close to the UV light source. The farther away the water is the more radiation is absorbed by the water. Meaning that with increasing distance you get weakening disinfection.  Proximity becomes even more critical in hard water.  Hard water sources leave a white chalky residue of calcium carbonate which covers the UV light bulb, making the radiation emitted significantly weaker.

Time is another significant limitation of UV disinfection. The amount of time pathogens spend in the UV greatly affects whether or not the pathogen is neutralised. This is similar to how people get worse sunburns the longer they are exposed to the sun.  Time is directly related to the flow of the water, if the flow is too much, the water will not spend enough time exposed to the radiation and will not be disinfected.  Slow moving water or even static water is best.

The efficiency of UV disinfection is greatly reduced by turbidity. Turbidity physically shields the organisms from the UV light. Exactly the way a beach umbrella shades people from the sun. This is called line of sight disinfection.  There is no disinfection in the shadows when using UV radiation.

Electricity is another limitation of UV disinfection systems.  They are limited in two ways by electricity.  First by the fact that  they are quite literally light bulbs placed underwater and secondly by fluctuations in the electrical source cause fluctuations in the UV radiation field emitted from the bulbs.  Both these problems are easily overcome.  By sealing the system in clear waterproof chambers can effectively keep the system safe from the water.  Fluctuations in the electrical source can be minimized through proper system design and using fresh/charged batteries in battery powered systems.

SteriPen Portable Ultraviolet Disinfection (from wikipedia.org)

Portability is a mixed blessing with UV disinfection systems. Smaller, pen-like devices are easy to transport, but are significantly less powerful. That means they need to be used on slower moving/still water and used for longer than larger UV systems.  Another mixed blessing of ultraviolet disifection is the fact that there is no disinfection residual left in the water.  Not having a disinfection residual is great if you are drinking the water immediately, otherwise recontamination can occur very quickly after the UV lamps are shut off.  UV is not enough if you plan on storing the water for a long period of time.

Recirculating the water to be disinfected a second or third time will greatly increase the chances of proper disinfection.  Remember that disinfection whether by UV or chlorine or any other method is one of the final stages of water treatment.  Forgetting to filter the water first will make disinfection significantly more difficult.  Regardless of the size of the of the system used, ultraviolet radiation can be used to supplement any water treatment process.

Sewage Emergency: Thunder Bay Flooding

Recently the city of Thunder Bay Ontario experienced devastating flooding. There was enough water to flood out the waste water treatment plant. This effectively shut down the sewage collection and treatment system for the entire city. This turned the entire city to a zone without sanitation.  Over 1000 houses needed to be evacuated, and some people needed to evacuate immediately.

Contaminated Water Flooding Thunder Bay (from news.nationalpost.com)

The flood hit the city at night, and people living in basement apartments woke up to furniture floating in sewage.  One lucky family woke up to their baby’s crib (and baby) floating in sewage.  The rest discovered that their house smelled horrible when they woke up.

What overloaded the system was a prolonged rainstorm above the 100 year storm levels and the normal waste water levels. Combined sewers meant that all this water was supposed to be treated at the waste water treatment plant.  When the flooding reached the facility, the pumps shorted out, as in most large facilities most of the control electronics (there are a lot) are stored in the basement.  Electronics underwater rarely fair well, this shut down the entire facility.  Large volumes of contaminated water had nowhere else to go and it started covering most of the city. People had anywhere from 4 inches to 6 feet of sewage in their homes.

Sewage Flooded Basement (from cbc.ca)

The city instructed residents not to use water, because all the flushed toilet water was ending up in basements and free flowing in the street. People didn’t stop washing and flushing. Now, when there is sewage everywhere there is a huge need to wash and keep clean. But when all you have is water for hygiene, all that waste will end up in the street or in your basement.  So there are strong reasons to use water, and strong reasons not to flush anything down the drain.  This is a good reason to have water-less cleaners available for when the waste has nowhere to go. Alternatively it is also a good reason to have short term storage for household waste.  There is no point in flushing the toilet if it just ends up in your basement.  I would personally deal with twenty feces filled buckets then one flooded basement.

When there is sewage in your house the environment becomes so toxic that even sleeping overnight can cause respiratory illnesses. Continue reading

How Does A Water Filter Work?

Whether you are building, operating or just buying a water filter, filtration is an essential part of most water treatment processes. Filtration is used in the counter top/faucet filter all the way up to municipal water treatment facilities serving tens of millions of people. Even in emergency and survival situations filtering with a shirt or other cloth is often the first thing recommended for water treatment. A shirt isn’t adequate on its own by a long shot, but it is better than un-filtered/untreated water. Used in conjunction with other water treatment steps, filtration makes the rest of the disinfection process significantly easier and cheaper.

We filter water primarily as part of the disinfection of water. Disinfection is the inactivation and removal of pathogenic organisms. Filtration is part of the removal portion of disinfection. (The other part being settling or clarification).
Filters work to physically remove contaminants from the water. They do this by passing the water through a filter media. The media presents a barrier to solids in the water. They literally collide into each other and become trapped. The media can be made of almost anything. As long as it has the ability to let water through and preventing solids from passing through. The pore size (size of space between the media) dictates the performance of a filter. The smaller the pore size the more that gets removed from the water. That sounds like smaller is better, but small pore sizes reduce the rate you can filter water and the total volume of water you can filter. It is always a trade off between ability to remove contaminants from the water and the ability to filter larger volumes of water.

Below is a diagram of pore sizes and which contaminants can be removed at a given pore size. Filters with smaller pore sizes tend to be more expensive. They require precise manufacturing techniques and maintenance.

Particle Size Diagram And How Fine A Filter Needs To Be To Remove Them

This trade off lead to the development of chemically assisted filtration. The filter media and the water itself is treated with chemicals. The water is treated with chemicals to make the particles in the water larger called floc (large groups of particles stuck together). At the same time the filter media is treated with a chemical to make the media attract and trap the particles in the water. Most chemically assisted media, has a electro-static charge opposite the one in the floc. Typically the media has a positive charge and the floc has a negative charge. Now instead of waiting for the particles to collide with the filter media, the floc is attracted onto the surface of the media (adsorbtion) and into the filter media itself (absorbtion). These types of filter media are said to be activated. Below is a diagram outlining the difference between straight filtration and chemically assisted filtration.

Direct Filtration Versus Chemically Assisted Filtration

Continue reading

What To Do When Your Backup Water Is Contaminated

Storing water in case of an emergency is a good idea. Having a reserve enables people to weather emergencies and minor service disruptions. A backup source of water is essential for emergency preparedness, three days without water will lead to death from dehydration, but serious and lifelong complications can occur well before you die from dehydration. Did you know that water sometimes needs to be retreated because clean water becomes contaminated? Water typically gets re-contaminated as people use water and they aren’t careful enough to prevent re-contamination, think about when you are washing up, hands are dirty and that leads to contamination of your stored water. Also a lot of stored water is stored for a long time “in case of emergency”. The problem with long term storage is the disinfectant residual deteriorates with time, reducing the water’s ability to prevent bacterial growth.

Preventing contamination is easier than removing contamination. Leave your stored water is a sealed and preferably airtight container. This physical barrier will stop bacteria in the environment from coming into contact with your drinking water. Next is to only open your reservoir with clean hands. Preferably washed with soap and water. It is better to pour the water you need for clean up before you make a mess. This is actually very important when you go to the bathroom, microscopic pieces of fecal matter on your hands will transfer to everything you touch, including the spigot/lid of your reservoir. Bacteria in that fecal matter will travel up the spigot into the water, it will only be a matter of time. Clean hands and routinely cleaning the exterior of your water storage tank/bottle/container/reservoir are essential to prevent contamination.

Another way to help prevent contamination is Continue reading

A City Without Sanitation

This article is another one designed to get people thinking about the hidden parts of our cities. The water and waste systems are easy to forget and are often willfully ignored.
People living in modern cities take sanitation for granted. Many people don’t realize that cities appeared after we developed sewers and efficient garbage removal. Quite literally, sewers are the backbone of civilization. It is misleading sometimes because many cities have truly ancient origins, however they were barely more than villages before sanitation. The problem with have large numbers of people in a small area like a city is that it gets filthy, and it gets filthy fast. The problem with living in filthy places is disease. Water borne, airborne and vermin borne diseases boom when there are lots of people in dirty places. The reason settlements didn’t grow beyond villages is disease would keep populations small.
Before sewers, sewage flowed freely in the streets. It eventually flows into the nearest surface water and leaches into the groundwater completely contaminating all water supplies.

Before Sewers Streets Had Rivers Of Sewage

Cities will quickly regress into a similar state once the efficient removal of waste is interrupted.  I have written about what a breakdown of the sewers system will look like. In a long term scenario, people will either move or they will throw their waste into the street.

Sewage Overflow in San Francisco

This seems so foreign to us, but that is exactly what happens when waste services stop. Continue reading

Non-Chlorine Pool Chemicals: Safe for Drinking Water?

When an emergency or a disaster strikes and you run out of clean drinking water, a clock starts counting down.  Three days is all that this clock has.  Three days is how long it takes a healthy adult to die of dehydration.  This journal entry is a continuation of my article on Pool Chlorine and Drinking Water. Many people with pools believe they can use this water as a back up source of drinking water,  whether or not that belief is a sound one is not always a simple answer.  While chlorine is by far the dominant disinfection agent used in pools there is a growing trend away from using chlorine.  In the first article (linked to above) I covered all the common types of pool chlorine chemicals.  In this article I will discus some of the other chemicals used in pools, and how they affect drinking water in survival situations.  I always recommend drinking the safest quality water you can get, clean untainted water that has been properly disinfected is always at the top of the list.  The advice that follows is for those situations where pool water and pool chemicals are better than tainted and untreated water.  That decision is something that everyone has to make for themselves when the emergency hits.

Salt Water Pool: (image source http://salt-water-pools.com)

Saltwater pools are the fastest growing among the alternative disinfectants. Saltwater pools may be safer to swim in, but are much more difficult to treat. If you were to drink the saltwater from a pool you would start an acceleration of the dehydration process as it takes more water to remove the salt from your body. To put it another way, it takes over one liter of water to remove one liter of saltwater. There is only one that can effectively remove salt from water is distillation. Boiling will not remove any salt at all. In fact you can boil it till all the water is gone and all the salt will remain in the pot. Distillation is the boiling of water and collection of the water vapor and steam. Then the cooling of the vapor and steam back into water into another container. Continue reading