Inorganic Elements in Tap Water
Water has a combination of many things in it, even when it reaches your home. According to a report sponsored by Ralph Nader, at least 2,110 different components have been found in drinking water supplies. Contaminants such as lead, asbestos, and trihalomethanes, could still be in your water supply after the water leaves the treatment plant. Things like nitrates, nitrites, calcium, magnesium, sodium, potassium, chlorine, fluoride, lithium, and sulphates are just some of the other inorganic (don't contain carbon) elements of our drinking water.
In this section, we will focus on some of the more popular constituents of water: chlorine, lead, fluoride, and arsenic.
The use of chlorine and its compounds is undoubtedly the most common disinfection method in the United States. As a disinfectant, chlorine is one of the public-health success stories of the 20th century. When it was first used to purify water in the early 1900s, typhoid fever, cholera, and dysentery virtually disappeared from the U.S. But the chemical has been under attack in recent years as a suspected carcinogen (cancer causing agent).
How does it work?
Chlorine gas (Cl2) is first compressed to its liquid form. The liquid chlorine reacts with water to form hypochlorous acid (HClO), a powerful oxidizing agent.
Hypochlorous acid kills disease-causing bacteria and some (but not all, as you'll find out in the next section) viruses and removes color from the water. Chlorine gas is very toxic and there is always danger of accidental release from tanks during transport. Perhaps the most serious problem is the finding that chlorine reacts with carbon compounds to form chlorinated hydrocarbons, including dichloromethane (CH2Cl2), chloroform (CH3Cl), and trichloroethylene (C2HCl3), which are all suspected to be cancer causing.
Considering the carcinogenic qualities of chlorine by-products, we should get rid of chlorine, shouldn't we? In 1991 Peru did just this. What happened? Over 300,000 Peruvians were stricken in a cholera epidemic.
So what can we do?
Chlorination is a very capable method of cleaning our water up, so any
new technology would have to match chlorine's effectiveness.
For example, chlorine not only kills microorganisms, but it keeps them
dead throughout the trip from the treatment plant to your home. Other
methods may produce clean water when the water leaves the plant, but not
many can prevent recontamination during distribution the way chlorine does.
But there are other methods that work. European treatment plants have shifted away from chlorine toward a greater emphasis on ozone (more on this later) and filtration, and these processes have not compromised the safety of their drinking water. European water has chlorine residuals more than 10 times lower than is typical in North America.
What is lead?
Lead is another element of tap water that has been the topic of much debate. Overexposure to lead over time can have severe health effects that can last a lifetime. Lead poisoning can cause damage to your brain, kidneys, nervous system, and red blood cells. In addition, it can stunt growth and has even been linked to crime and anti-social behavior in children.
How does lead get into my drinking water?
Most of the lead in drinking water comes from the lead in pipes that bring water to your home, not from the treatment plant. As early as ancient Rome, people have used lead to transport water. Lead is used primarily for lead pipe lines, brass fixtures, and lead solder (pronounced "sod-er"; it is used to cement metal parts together).
We have long known about lead's toxicity, but only recently has much
been done about it. People were first aware of the problem in the
early 1900s. By 1930, houses were no longer built using lead pipes, but
lead pipes were still used to join homes to public water supplies.
It wasn't until 1986 that lead pipes were banned from use in our
drinking water supplies. In 1988, lead solder was also restricted.
Even still, over 90% of homes in the U.S. have pipes that contain lead
or lead solder. A little scary, huh?
What are some of the things that determine lead levels?
The pH of the water affects how easily lead dissolves from pipes, solder, or fixtures into the water. Water with a very high or low pH can dissolve lead from the supply pipes, faucets, or solder. So proper water pH is important so lead doesn't find its way into our water as easily.
Water containing a lot of minerals is termed hard water, while
water with few minerals is called soft water. Hard water can
actually offer some protection against lead contamination because mineral
build-up on the inside of pipes reduces contact between water and the lead
How can I treat my water to remove lead?
If testing shows high levels of lead, there are a couple of things you can do to minimize lead concentration in your water. The longer that water sits in pipes, the greater the exposure to lead. Before using water for drinking or cooking, run the cold water for a minute until it is as cold as it can get. This will flush out the water that has been sitting around for awhile so lead concentration won't be as high. Also, use only cold water for drinking and cooking since hot water dissolves lead more quickly than cold water.
If fluoride sounds familiar to you, pick up a tube of toothpaste and you'll see why. Every major brand of toothpaste today contains fluoride. It is arguably the biggest advancement in tooth care ever. But fluoride is probably best known because of the controversy surrounding its addition to public water supplies. People have debated over the risk involved with fluoridation since 1945, when fluorides were first introduced into public water supplies at a concentration of one part per million (ppm).
Whatever the case, one thing is for sure. Fluoridation has been a powerful weapon in the battle against tooth decay in the U.S. But fluoride's ability to strengthen teeth has never really been in question. What has been asked is whether we need as much fluoride as we get. After all, toothpaste is fortified with fluoride and more is present in the foods we eat. Do you think our water needs to be fluoridated as well?
What's wrong with getting too much fluoride?
Well, for one thing, tooth discoloration can occur, forming yellow or brown pits and patches on teeth (long term exposure at levels greater than 2.0 ppm). Long term exposure at higher levels (4.0+ ppm) can cause bone spurs and possibly even birth defects.
At levels around 1.0 ppm, however, fluoride is a powerful supplement to the diet. Aside from fighting cavities, it has been shown to strengthen bones and decrease the incidence of osteoporosis (a disease that weakens the bones) among postmenopausal women by 50 percent.
Interestingly enough, here in San Diego the water is not fluoridated,
even when given the obvious benefits. Can you think of some reasons
why? In San Diego, the cost of adding the fluoridation system is
one of the biggest deterrents...
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What is arsenic?
Arsenic is a naturally occurring element that is tasteless and odorless. As a component of rock in the earth's crust, arsenic works its way into groundwater and enters the food chain through either drinking water or by eating plants that have absorbed it. Arsenic is found within our bodies in very small amounts and is actually an essential nutrient in our diets.
So why all the fuss then? Well, the problem is that it is easy to get arsenic toxicity because even the smallest additional amount beyond what we require can cause health problems.
What are the signs of arsenic toxicity?
Perhaps the single most common sign is the formation of light and dark spots on the skin. These skin changes can ultimately progress to skin cancer. In addition, arsenic ingestion has been reported to increase the risk of cancer inside the body, especially in the liver, kidney, bladder, and lungs.
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