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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