Is
Your Water Safe to Drink?
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) 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
5) biological pathogens, including bacteria, viruses and protozoa.
Particulate
Problems associated with the particulate category involve mainly
appearance, smell and taste. Particulate 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