Is Your Water Safe to Drink?
Identifying the main water contaminants and what you
can do about them
By
In
1989, Congress struck a blow to the Safe Drinking Water Act when it stipulated that
public drinking water supplies must be made available "economically."
This requirement meant that standards involving contaminants must consider not
only the quantity of contamination but also the cost of removing contaminants.
When
drinking water is declared "safe," it means only that the water's
purity meets government standards. Now that the requirement of
"economy" has been thrust into the drinking water safety equation, it
is questionable whether we can count on government standards to protect our
health.
In
1986, the U.S. Environmental Protection Agency estimated that some 40 million
Americans were using drinking water containing potentially hazardous levels of
lead. Acute lead poisoning can cause severe brain damage and even death.
Effects of chronic, low level lead exposure are subtle, and infants and
children are most vulnerable. Learning disabilities and hyperactivity have been
associated with lead exposure, as have increased blood pressure, stroke, loss of hearing, chronic anemia, nerve damage and
infertility.
Current
government standards permit 50 ppb (parts per billion) of lead in drinking
water. A stricter standard of 7.5 ppb has been recommended, but it is estimated
that it would cost $5 billion to accomplish this. To reduce the lead in public
water to 5 ppb would cost an estimated $21 billion.
Is it worth the cost?
There
is no "safe" level of lead in drinking water. And keep in mind that
the government's 50 ppb standard only applies to water as it enters your house,
not how it comes out of your tap.
Most
lead enters the water from home plumbing. Plumbing installed before 1930 most
likely includes lead pipes. Even in homes built more recently; the solder used
to connect copper pipes may contain lead.
Unfortunately,
lead is merely one of the possible contaminants in your water. Testing by an
independent laboratory may disclose that there are unacceptable levels of other
toxins. Fortunately, there are various methods of home water treatment
available for specific problems.
Water contaminants
There
are five principal groups of water contaminants: 1) particulate, which includes
particles of rust, dirt and sediment; 2) dissolved inorganics,
including heavy metals (mercury, lead, chromium, silver, etc.), and asbestos;
3) organics, which include calcium and magnesium carbonates, the components
that make water "hard," and nitrates, chemical solvents, pesticide
residues, and industrial pollutants; 4) radiological contaminants, both natural
and industrial, such as radon and radium; and 5) biological pathogens, including
bacteria, viruses and protozoa.
Particulate
Problems
associated with the particulate category involve mainly appearance, smell and
taste. Particulates can be removed with simple filters. Filters are inexpensive
and are made from fabric such as cotton, wool or fiberglass. Filters are
effective only against larger particles. They are ineffective against dissolved
toxic chemicals.
Dissolved inorganics
Dissolved
inorganics are a very serious problem, especially
lead, as previously discussed. However, another major inorganic pollutant is
nitrate. Nitrate contamination occurs mainly in groundwater, especially in
agricultural areas. Chemical fertilizers and manure from animals are
particularly concentrated sources. The danger is particularly great for children.
Nitrates are converted to nitrites in the digestive tract, and nitrites
interfere with the ability of blood to carry oxygen, which can result in brain
damage and death.
Organics
Dissolved
organics include some serious problems. Many public water supplies contain low
levels of organic compounds created as byproducts of water chlorination.
Although these compounds are highly toxic, they are justified as acceptable
because of the effect that chlorination has on microorganisms. Pesticides,
industrial effluent, and hazardous waste sites are other sources of organic
pollutants. These chemicals are associated with liver, kidney, and nervous
system damage, and possibly cancer.
Dissolved
organics include some harmless, although annoying, chemicals such as calcium
and magnesium carbonates. These may leave deposits on sinks and tubs, and they
may interfere with the effectiveness of soap. From a nutritional viewpoint,
these minerals are present in extremely small amounts, and, even if fully
absorbed, would contribute little nutritional benefit.
Radiological contaminants
Radiological
contaminants, such as uranium, radium and radon, occur naturally in various
parts of the country. The most serious effects of radiation exposure include
birth defects and cancer.
Biological pathogens
Biological
pathogens, such as viruses, bacteria and protozoa, are uncommon in public water
supplies due to chlorination. But some organisms are becoming resistant to
chlorine, and this may become more of a problem in the future.
Water purity checks
Remember,
private water supplies are not subject to government testing, and it is up to
the individual to periodically test for biological contamination.
To
determine the level of purity of your water, there are several options.
If
you have municipal water, ask the local utility for a copy of its latest water
analysis. Federal law requires periodic testing and making the results
available for inspection. These tests, however, reveal only the conditions of
the water as it leaves the reservoir or treatment plant. They do not reveal if
lead is leaching into your water from your plumbing. You can have lead levels
checked by a private testing laboratory.
If
your water is from a well, you can call the local public health department to
inquire about groundwater problems in your area. In general, if your water is
from a private well, you should also test for organic chemicals. In
agricultural areas, nitrates and pesticides should be among the requested
tests. If your house is more than 30 years old or contains copper pipe, you
should test for lead.
Independent tests
Independent
state-certified laboratories should do tests. They are often listed in the
yellow pages under "Laboratories-Testing." There are also mail order
laboratories. Three that were listed by Consumer Reports in January, 1990 are: WaterTest (33 South Commercial St., Manchester, NH 03101,
telephone 800-426-8378); National Testing Laboratories (6151 Wilson Mills Rd.,
Cleveland, OH 44143, telephone 800-458-3330); Suburban Water Testing Laboratories
(4600 Kutztown Rd., Temple, PA 19560, telephone 800-443-6595).
Tests
can cost from $30 to $200 depending on how many tests you request. Consumer
Reports found the tests to be generally reliable but recommended a test by a
second lab to verify any suspicious results.
Home water treatment
You
can do quite a bit to improve your water purity. The three primary home water
treatment methods are: 1) activated carbon filters, 2) reverse osmosis systems,
and 3) water distillers.
Activated carbon filters
Activated
carbon filters work by a process known as adsorption whereby the carbon
attracts and holds various pollutants in a honeycomb of tiny channels and
pores. They are best suited for removing bad tastes, odors, chlorine, organic
chemicals, and pesticides. They are not effective against microorganisms, lead
or heavy metals, sodium, fluoride, or minerals that produce hardness.
Drawbacks-Carbon
filters can become breeding grounds for microorganisms. Sediment in water can
clog the filter. Effectiveness declines over the period of
use-it is necessary to be diligent about replacing cartridges.
Advantages-Activated
carbon filters are the least expensive of the three main water treatment
methods. The solid carbon filters are considered the best, while powdered carbon
filters are the least recommended.
Reverse osmosis
Reverse
osmosis uses semipermeable membranes, which keep out
many pollutants. Water pressure, minimum of 40 psi
(lbs. per square inch) forces the water against the membrane.
Reverse
osmosis is effective at removing inorganic contaminants, such as dissolved
salts, fluoride, nitrate, lead and some organic contaminants. It is not
effective against high levels of hardness minerals.
Drawbacks-Reverse
osmosis systems waste a lot of water. Only 10-25% of the water passing through
the unit is forced through the membrane. The rest goes down the drain. Reverse
osmosis is slow, 3-6 gallons per hour. There are two types of membranes. The
faster, more efficient of the two degrades in the presence of chlorine. Reverse
osmosis systems should be used in conjunction with prefilters
for sediment and post-carbon filters to remove dissolved organic chemicals,
such as pesticide residues, etc. Efficiency drops with low water temperature.
These systems can be expensive to install and maintain.
Advantages-Reverse
osmosis systems do not use electricity, and the cost per gallon of treated
water is less than distillation.
Water distillation
Water
distillers work by boiling water and then condensing the steam into purified
water. Distillation is most effective at removing sediment, dissolved inorganics (including heavy metals), radiological
contaminants, and biological pathogens. It is less effective against some
volatile organic compounds unless combined with a carbon filter.
Drawbacks-Water
distillation is slow and uses considerable electricity, making it the most
expensive method of water treatment. Distillers require regular cleaning, are
noisy, and may vent off volatile chemicals. They also give off considerable
heat and are expensive to purchase.
Advantages-Distillation,
especially when combined with a carbon filter, is the most effective means of
home water treatment.
Recommendations
Which
system of home water treatment to choose depends on the type of contamination to
be removed as well as financial considerations.
The
accompanying chart summarizes which systems are effective against various
contaminants. Activated carbon filters can be used in combination with reverse
osmosis or distillation for complex problems.
Another
alternative is to purchase treated water from bottled water companies. We
recommend water purified by steam distillation because "purified"
water or spring water may not be better than what comes out of the tap.
For
more information see our WEB site at www.healthpromoting.com