Environmental Health Hazards

What you donít know can hurt you.

We often take for granted the wonder of nature surrounding us - a refreshing spring rain, a colorful sunset, a quiet winter snowfall, a beautiful summer day. When classes start in the fall, we assume there will be hot water for showers after gym and cool water from the tap to drink. We don't even give it a second thought that there will always be air to breathe.

Perhaps we should give some second thoughts to those things of beauty, comfort, and necessity that seem so obviously available to all of us. Modern industrial nations are polluting the land, water, and air of our planet to a degree that makes national boundaries meaningless. We are confronted with the specter of global pollution.

It is important for us as individuals to be aware of the dangers of pollution and to safeguard our health from the effects as much as we can. It is even more important that we participate in a lifestyle that contributes to this pollution as little as possible. Everyone is responsible for cleaning up the planet and for helping to improve a battered environment.

A sorority decided to spend one day a month cleaning up one of the neglected local parks in an effort to improve the environment. The members solicited contributions and volunteered their time to pick up trash, trim bushes, and plant flowers and trees. Their efforts were rewarded with a heightened awareness of the environment and a pleasant place to picnic, relax, and enjoy nature.

When a student started a car pool to save money, he wasn't thinking about improving the environment. But when his posted notice initiated four or five car pools for other areas, the college began a carpool service that resulted in a financial saving for students and contributed to improved air quality.

Although these changes may seem minor when we are confronted with global pollution, changes at the individual level are essential if the human race is to survive the many years of reckless disregard for the environment.

During your lifetime you will see, and be affected by, many environmental pollution problems. The quality of our air, water, and land is being seriously undermined by the hundreds of millions of tons of toxic waste that our industries and automobiles dump into the earth and air each year.

The Union Carbide accident in Bhopal, India; Three Mile Island in Pennsylvania; Chernobyl in the Soviet Union; Love Canal in New York; Times Beach in Missouri; the London "killer smog" of 1952; the poisoned wells of Woburn, Massachusetts-all are examples of ecological disasters, some of which have resulted in the deaths of thousands of people. The deaths of thousands more have probably gone unrecognized as environmentally caused because science has not had the technology or the resources to link diseases with their causes. Substances are now being recognized as poisonous at nearly any detectable level, but for many years tons of these chemicals have been dumped into our environment with almost total disregard for the consequences.

In 1973 a fire retardant instead of an animal feed supplement was mistakenly sent to farmers in Michigan. The fire retardant contained polybromated biphenyl (PBB), which has been associated with birth defects, cancer, mental disorders, and diseases of the skin, nervous system, and sensory organs. For over a year, the meat and dairy products contaminated by the mistaken product were marketed throughout Michigan and other states. In tests performed in southern Michigan, 96 percent of the women had detectable levels of PBB in their breast milk. Incidents like this are frightening, and the full effects may not be discovered for years.

Mankind's greatest challenge in the next 50 years will be to begin the cleanup of the environment so that the species can survive. Even the most pristine areas of our environment are being catastrophically affected by acid rain, pesticides, nuclear radiation, airborne dioxins, and photochemical smog.

What is smog?

Smog is a complex chemical soup that pollutes the air. The term smog originally came from England, where a combination of smoke from coal-burning fireplaces and industrial air pollutants mixed with fog to create an extremely foul, unhealthy atmosphere.

Generally, smog refers to the airborne pollutants that fill the air in nearly every major city in nearly every country. There are basically two types of smog. One has sulfur dioxide as the main component and is the result of burning coal, oil, and other fossil fuels for heat and in manufacturing processes. This type, which resulted in the deaths of over four thousand people in London during a two-week period in 1952, is often referred to as London smog. Sulfur dioxide smog is more common in the major midwestern and northeastern industrial centers in Illinois, New York, New Jersey, and Pennsylvania.

The other type, called Los Angeles, or photochemical, smog, is mainly produced by automobile emissions, power plants, and other industrial processes. It contains hydrocarbons, nitrogen dioxide, and carbon monoxide. Nitrogen dioxide and hydrocarbons react chemically when they are "cooked" by sunlight and convert oxygen into ozone. Ozone is the major ingredient of photochemical smog, accounting for 95 percent of its composition. It is a colorless, pungent, toxic gas. Most of what you see as smog is the particulate matter that is the result of incomplete combustion. However, what you cannot see does the most damage to your lungs.

What health problems can smog cause?

Breathing smoggy air can result in eye, nose, and throat irritation, acute and chronic bronchitis, asthma, headache, and malaise. The typical symptoms are burning, itching eyes and throat, cough, and shortness of breath. Smog can cause reduced lung function that may last for as long as a week after exposure.

Exercising in smoggy air can make these effects even worse. A spectator at an athletic event during a first-stage smog alert may not notice the effects. However, the athletes participating in the event may have as much as a 25 percent decrease in lung function. This results in poor performance, shortness of breath, burning in the chest, and a general feeling of malaise.

Children and older adults are usually more susceptible to the deleterious effects of smog, as are people with asthma, bronchitis, and other chronic lung and heart disease. For someone with asthma or bronchitis, the air pollution that necessitates an alert can bring on an attack. Chronic exposure to ozone, one of the primary components of automobile smog, has damaged lung structure in test animals. It is reasonable to assume the same results in human beings, although ethically it is unacceptable to do similar research on them.

In addition to the respiratory system, smog affects the cardiovascular system. This is primarily the result of breathing carbon monoxide. Because it is produced by automobiles, the levels are highest near expressways, in underground parking garages, and so forth. Carbon monoxide reduces the oxygen-carrying ability of the blood and therefore the amount of oxygen supplied to the heart.

If the air pollutants include lead, the result can be anemia, and severe lead poisoning can cause heart, brain, lung, and blood damage. Learning disabilities and central nervous system disorders, particularly in children, may result from lead accumulation in the body. The increasing amounts of lead in the air led to the government 5 demand that all new automobiles burn unleaded gas.

Research is currently being conducted to measure pulmonary function in residents of high-smog and low-smog areas. It may take many years before these studies are completed and the results are known. Preliminary findings have shown acute declines in lung function. Long-term follow-up of residents in high-smog areas will help determine what, if any, chronic diseases are linked to smog.

What does it mean when there is a smog alert?

The Environmental Protection Agency (EPA) monitors the levels of six different substances in the air of most major cities-sulfur dioxide, particulates, nitrogen dioxide, ozone, lead, and carbon monoxide. They are regulated under the Clean Air Act of 1970. When the levels of these substances, primarily ozone, exceed a certain standard, EPA announces a first-stage smog alert. The air is unhealthy for everyone.

A second-stage smog alert indicates the air is hazardous and exercise should be avoided entirely. However, it can be very difficult to stop breathing! You may not even know you are in a smog alert until you read about it in the paper the next day.

Hundreds of other toxic chemicals are being released into the air that are not covered by federal regulation and are not monitored by any agency of the state or federal government.

How can I avoid smog?

Exercise in the morning hours, when ozone levels are low. Also, exercise away from automobile traffic. Try to avoid driving during the heavy commuting times. Your automobile provides little protection from smog.

If there is a smog alert where you live, minimize your driving as much as possible and stay indoors. This will reduce your exposure by as much as 50 percent as well as reduce your contribution to the problem. If you are susceptible to the effects of smog, it is a good idea to reduce your exposure. The automobile is very closely associated with smog, and for good reason. Approximately half of the photochemical smog is produced by automobiles.

Because photochemical smog depends on sunlight to produce ozone, smoggy conditions usually begin to increase around 1 p.m. They don't start to dissipate until after 7 p.m., when most commuters are home and the sun is going down. If you must commute during rush hours, be aware that you may return home with a headache. It could be the result of breathing smoggy air and not the result of stress.

How can I help with the air pollution problem?

You can contribute to cleaner air by using public transportation, riding a bicycle, or even walking whenever possible. Driving an economy car or an electric car will also lead to less air pollution. Make sure that your car is properly tuned and that air pollution control devices are properly functioning.

Are there other types of air pollution besides smog?

Many other substances are released into the air by chemical manufacturers, municipal incinerators, and even fireplaces. They are called "point source" air pollutants and can be extremely caustic and threatening to health. The Union Carbide disaster at Bhopal, India, is an example of a point source air pollutant. Other examples are the Three Mile Island and the Chernobyl nuclear power plant radioactive discharges.

Many chemical manufacturing plants emit air pollutants through their manufacturing processes. These may not be quite so dramatic as the Chernobyl and Bhopal discharges, but in the long run, exposure to some of these chemicals may be just as deadly. These pollutants, including dioxins and furans, can be lethal in minute doses, and they do not remain in the air forever. When they settle, a few yards or hundreds of miles away, they can be absorbed into the groundwater and begin the slow process of moving up the food chain until they reach our dinner table. Many of these chemicals accumulate in the body and may be the cause of various cancers.

Chemicals such as benzene, chlordane, xylene, toluene, lead, mercury, cadmium, selenium, arsenic, tetrachloroethylene, chlorophenols, dioxins, furans, and hundreds of others are present at detectable levels in human body tissue. There is not a person alive today who will not have some synthetic substance show up in the blood if it is looked for.

These substances tend to collect in the fatty tissue of the body. Many are potent carcinogens (agents that cause cancer) and mutagens (agents that cause birth defects). They may be slowly ticking time bombs waiting 20, 30, or 40 years after entry to confront the body with a cancer of some type. They may be silent cofactors in causing disease, along with well-known cancer-causing substances like tobacco, asbestos, and others. Their effects may not even show up until we have children with birth defects such as spina bifida, cleft palate, Down's syndrome, or heart abnormalities. And they can increase the rate of miscarriage and stillbirth.

TCDD, a form of dioxin, is considered by many experts to be the most toxic chemical ever created. EPA experts believe that exposure to dioxins already in the environment may be causing 1 cancer per 10,000 people.

In the near future, research will demonstrate more clearly the relationship between cancer and environmental pollution. In 1964 the World Health Organization estimated that 60 to 80 percent of all cancers were environmentally caused. The American Cancer Society believes that 56 million Americans will develop some form of cancer, about one person in four.

Is indoor air pollution really a health threat?

Very much so. Pollutants in indoor air may pose a greater threat to health than those in outdoor air do. Some modern school buildings with sealed windows have been closed because of complaints by students, faculty, and staff of burning eyes and lungs (the so-called sick building syndrome). The short-term effects of breathing polluted indoor air are eye irritation, headache, dizziness, nausea, sleepiness, and poor concentration.

Indoor air pollutants have many sources. They may be sucked in from the outside by the ventilation system. Building materials sometimes release pollutants that circulate indoors. Building maintenance workers may use solvents and other irritating chemicals that are recirculated in the air because of inadequate ventilation. Indoor activities such as smoking, sweating, and just plain breathing can release air pollutants like methane, carbon dioxide, contaminated water, and particulates into a limited indoor air supply.

Modern construction techniques have promoted the use of materials that can give off such noxious fumes as formaldehyde from foam insulation and radon (a disintegration product of radium) from concrete. Other materials such as asbestos, pesticides, fiberglass dust, carpet adhesives, wall insulation, plywood, and particleboard can all release dangerous airborne chemicals if they are improperly used.

Wouldn't indoor air pollution have a noticeable odor?

We often think of air pollution as causing unpleasant odors. However, the worst pollutants very often can not be smelled at all, even at fatal levels. Every winter people are killed when their malfunctioning space heaters spew carbon monoxide into an unventilated room. These heaters should be checked annually to ensure that they are functioning correctly, and they should not be operated without proper ventilation.

Carbon monoxide is an invisible, odorless gas that can accumulate when there is inadequate ventilation, or a lack of oxygen to replace the oxygen consumed by the heating system. It is also produced by automobiles, but it is nearly impossible for it to accumulate outdoors to a level that will cause asphyxiation. Carbon monoxide can kill because in high concentrations (for example, in a house), it displaces oxygen in red blood cells. The red blood cells can no longer deliver oxygen to the brain or other tissues. Low concentrations of carbon monoxide displace only some of the oxygen in the red blood cells. This results in relatively minor symptoms like the headache and irritability caused by outdoor smog.

Inhaled particulates of asbestos lodge in the lung and can be transported to the lymph nodes, resulting in a fatal degenerative lung disease called asbestosis and a virulent cancer called mesothelioma. Cigarette smoking combined with asbestos exposure multiplies the risk of dying of cancer 54 times.

The cost to remove asbestos insulation from over 14 thousand of the nation's schools has been estimated by the government at 1.4 billion dollars! It has also been estimated that over 100 thousand persons have already died from asbestos exposure. Even if every shred of asbestos could be eliminated from now on, there would still be 350 thousand deaths in the next 10 years from previous exposure.

The major problem in the home, however, comes from combustion gases, particularly carbon monoxide, nitric oxide, and smoke from tobacco, kitchen stoves, heaters, wood stoves, and fireplaces. When these are combined with inadequate ventilation, especially in the winter months, the result can be poisonous air.

Other problems develop when air-conditioning units are not properly maintained. Microbes growing on the filter can spread throughout a building. When this happened in Philadelphia at the 1976 American Legion convention, a mysterious form of pneumonia, later called Legionnaires' disease, was fatal to some of the conventioneers. The causative bacterium was named Legionella pneumophila.

Indoor air pollution can be created by the improper use or overuse of cleaning solvents, floor waxes, furniture polish, bathroom cleaners, and room deodorizers. When you use these products, be sure to open all windows and provide good ventilation with a fan.

Other sources of indoor air pollution are the indiscriminate use and storage of pesticides, herbicides (weed killers), cleaning fluids, paints, and solvents. People who work regularly with chemicals such as paints and solvents suffer increased rates of leukemia and other types of cancer.

If you use a bug bomb to rid your room or apartment of fleas left by a previous occupant's cat, follow the instructions very carefully. If you are applying pesticides or herbicides to the garden, use protective gloves to avoid absorbing these substances through the skin, and don't breathe the fumes. Simply mishandling the liquid bleach you use in your laundry or swimming pool can result in permanent lung damage from inhaling chlorine gas fumes.

You need only read the labels on the containers under the sink to discover you have a great number of very poisonous chemicals right there. Here is a list of common household aerosol spray products and a few of their ingredients:

Furniture polish dinitrobenzene, 1,1 ,l-trichloroethylene, petroleum distillates, silicone,wax morpholine
Spot removerperchloroethylene
Oven cleaner sodium hydroxide, hydroxyethyl cellulose, polyoxyethylene fatty ethers
Drain cleaner † 1,1,1 -trichloroethylene, petroleum distillates
Disinfectant phenol, cresol
Chlorine bleach 4-chloro-2-cyclopentylphenol, diethanolamidolauric acidamide
Tile cleaner tetrasodiumethylenediamine
Prewash treatment perchloroethylene, petroleum distillates
Window cleaner sodium nitrite, isopropyl alcohol, ethylene glycol, ammonium hydroxide
Disinfectant spray trusopropanolamine morpholine
Air freshener propylene glycol morpholine, ethanol
Deodorant spray hydrated aluminum chloride, isopropyl myristate talc, triglycerides
Hair sprayvinyl acetate copolymer resins, polyvinylpyrrolidone resins, ethanol, lanolin
Shaving foam stearic acid, triethanolamine, menthol, glycerol

The indoor use of these sprays as well as many common paint sprays, insecticides, plant sprays, and pet sprays can result in the buildup of acute toxic levels in a very short time. Aerosols should be used with extreme caution. Very often these chemicals miss their targets when sprayed and mix with dust to be recirculated by the ventilation system if they are used indoors.

In office buildings and schools, the innocuous-looking copying machine can be the source of ammonia or methanol fumes or of ozone. The photocopier should be well ventilated directly to the outside.

By far the most difficult indoor air pollutant to control or eliminate is tobacco smoke. Smoke subsides very slowly and is adsorbed on nearly all indoor surfaces, causing it to linger for days. The heavier components of smoke penetrate furniture, clothing, bedding, carpets, and drapes and cannot be completely removed. The negative effects of smoking are so strong that smokers who live in unpolluted areas still have a four times greater incidence of respiratory and circulatory diseases than do nonsmokers who live in the most polluted areas of the world.

Recent studies have demonstrated that passive smoking, or breathing air that is contaminated by the smoke of others, is a significant health risk. A study in Japan found that the nonsmoking spouses of men who smoked died from lung cancer at twice the rate of other nonsmokers. According to the 1979 surgeon general's report, smoking is related to 350 thousand deaths a year in the United States, nearly one out of five deaths. If you are a nonsmoker, it would be wise not to tolerate smoking in your indoor environment. If you are a smoker, do your friends and associates a favor and smoke outside. Better yet, do yourself a favor and quit smoking altogether.

Why is the earth's ozone layer being depleted? Could it be a threat to health?

The earth's ozone layer in the upper atmosphere filters and absorbs much of the sun's ultraviolet radiation. This naturally occurring ozone is not to be confused with the ozone produced by smog. By filtering the ultraviolet radiation, the ozone layer in the stratosphere is one of the factors that make life on our planet possible.

In 1954 we began to use chlorofluorocarbons as propellants in spray cans and freon in refrigerant devices because these compounds are inert, meaning that they do not break down and combine with other substances. Because they are chemically inactive, they survive their initial usage and are released into the atmosphere. Eventually they rise into the stratosphere, where the sun's energy breaks them down, releasing chlorine atoms that destroy the ozone whose protective layer surrounds the earth.

In 1978 the use of chlorofluorocarbons as propellants was banned by the EPA. However, they are still produced and used as refrigerants and in other commercial applications.

The result of the thinning of the ozone layer, which has been predicted to reach between 4 and 30 percent, is likely to be a substantial increase in the number of skin cancers. The rate of skin cancer in this country has already been called epidemic; whether the source is the thinning ozone layer is irrelevant to the individual who gets the disease.

Can I get cancer from sunburn?

Yes, you can. Protection from the sun is very important. In some areas of the United States, skin cancers have increased by 200 percent. Most of this has been attributed to the lifestyle, which decrees that a tan is essential and somehow healthy, when in fact the opposite is true. Sunburn should be avoided entirely. If you want to tan, do it slowly, gradually increasing your exposure so that you don't burn and peel. Skin cancers usually develop at sites that have suffered severe sunburn many years earlier, even in childhood. Repeated burning on these sites increases the chance that a cancer will develop.

The nose, ears, and shoulders are prime targets for sunburn and skin cancer, and extra caution should be taken to protect them with sunscreen, hats, shirts, and shade.

What Is the greenhouse effect?

It is the warming effect of carbon dioxide on the earth and lower atmosphere. The combustion of fossil fuels, such as oil and coal, releases carbon dioxide (C02) into the atmosphere. Over the last hundred or 50 years, the amount of C02 has increased about 13 percent. Much of this increase has taken place in the last 40 years. Scientists fear that a continued increase in atmospheric C02 could raise worldwide temperatures over 5 degrees Fahrenheit. This could have devastating effects on the environment by melting the polar ice caps, expanding deserts, flooding coastlines, and reducing global food supplies. Even if there were no further release of carbon dioxide into the atmosphere, the earth's temperature would continue to rise for the next 15 years.

What is acid rain?

Acid rain is the result of the buildup of sulfur dioxides and nitrogen oxides that mix with water in the atmosphere. The moisture becomes very acidic, sometimes reaching the acidity of vinegar. When it returns to earth as rainfall, often hundreds of miles from the source of the pollutants, it can destroy lakes, streams, and forests by making them too acidic to support life.

In New York, as many as 200 lakes are now devoid of life. In Sweden, an estimated 15 thousand lakes no longer contain fish. Thousands of acres of Canadian forests are being destroyed by acid rain that drifts north from the United States.

Coal-burning power plants are the main source of the sulfur dioxide, and automobiles are the main source of the nitrogen oxide. Not only the fish and the trees are being destroyed by acid rain. It dissolves metal and stone in statues and buildings. In the last 40 years acid rain has done more to destroy such priceless treasures as the Parthenon in Athens than the weather did during the preceding two thousand years.

Although it may not be a direct health threat, acid rain is a symptom of a dying environment. A more direct health threat is acid fog. It is basically the result of the same conditions, but because the acid is suspended in particles of fog, we are more likely to inhale it. This can cause coughing, wheezing, eye and throat irritation, bronchitis, asthma attacks, and decreased lung performance. It also kills cells in areas of the nasal passages where cancer most commonly occurs.

How does water pollution affect health?

Water pollution, even in water we don't drink, is a serious threat to health. When certain Japanese companies released mercury into the Pacific Ocean, they had no idea that it would build up in the environment. It was not until 52 people from the village of Minamata died and over 100 more became seriously ill that the mercury buildup was discovered in the fish the people of the village were eating. Birth defects continue to cripple the children of the village. Although the release of mercury into the environment is now strictly regulated, there are innumerable other chemicals that are not. The impact that many of these chemicals will have on health is yet to be discovered. Others are already identified as carcinogens, mutagens, and just plain poisons. Chemicals like pentachlorophenol dioxin 5, trihalomethane, polychlorinated biphenyl (PCB), and hundreds of others are seeping into groundwater and surface water all over the country.

Some of these chemicals have already been banned, and millions of tons of them have been dumped in over 10 thousand toxic waste sites. We do not even know the location of many of the sites, which are slowly spreading their boundaries as the poisons are leached out, polluting the very ground much of our water comes from. These chemicals have created a toxic waste nightmare that has barely been recognized. The multibillion dollar federal Superfund program created to deal with toxic wastes was extended by Congress but is inadequate even to clean up these sites, let alone deal with the disastrous health effects that are sure to result.

Since the 1940s, DDT has been the most popular and effective pesticide ever used. The release of DDT into the environment continued unabated for many years. Rain washed it from the fields into the rivers and streams until it reached the oceans. It was consumed by microscopic plankton, in turn consumed by shellfish, fish, and birds. Through a process called biological magnification, chemicals passed up the food chain accumulate at greater levels in the species near the top. Man, consuming grains, fish, birds, and meats, is close to the very top of the food chain.

DDT causes birds to lay eggs with very thin shells; its presence in the food chain threatens to bring about the extinction of the Bermuda petrel, the brown pelican, the osprey, and the peregrine falcon. In man, DDT is suspected of being a carcinogen and a mutagen. Not until 1969, when entire species of birds were threatened with extinction, was DDT banned in the United States. Now, years after it was outlawed, it shows up far away in the penguins of Antarctica, and we all have traces of DDT in our bodies. Many foreign countries continue to use DDT without control, and it still pollutes the environment through the groundwater.

Should I drink water from the tap?

Maybe and maybe not. Our drinking water is often referred to as the cleanest in the world. In some respects this is true. If you are supplied with water from a metropolitan water supply, bacteria such as Escherichia coli, the shigella groups, and those responsible for typhus and cholera are routinely destroyed by chlorination. Chlorine is added to the water in minute doses to kill these bacteria that cause serious intestinal infections.

However, minute traces of pesticides and other organic chemicals in the water supply may combine with the chlorine to form extremely dangerous compounds called trihalomethanes. One of these compounds is chloroform, a known carcinogen. In a 1975 study, the EPA found traces of chloroform in the drinking water of all 80 cities it studied. Chlorinated water has been associated with increased rates of rectal, colon, and bladder cancer.

In most major cities, over a hundred organic chemicals can be found in the drinking water. Using bottled or distilled water may be a prudent idea, but be wary of the source of these "mountain pure" waters. Some may come from wells that are no safer than sources of city water. The laws governing the purity of bottled water are the same as those that regulate tap water. And companies that recycle bottles may not be as successful as you might think at cleaning them between uses. If a gardener uses the water bottle to mix up a batch of insecticide, you may be the unfortunate recipient of a nasty dose of poison.

Water filters are also an option. Be sure you investigate the quality of any water filter system thoroughly. Filters that screw on to the faucet are generally useless.

The wells that supplied public water to the city of Woburn, Massachusetts, were found to be contaminated with extremely high levels of chloroform, trichloroethylene, tetrachloroethylene, 1,1,1 -trichloroethylene, and dibromochioromethane before they were shut down. These wells were associated with a cluster of rare leukemias in the children of that town.

Can fluoride in the water system cause problems?

Fluoride is added to many city water supplies because it has been documented that it drastically improves the dental health of a community by reducing cavities. About the only time fluoride causes health problems is when the amount is excessive. This rarely happens because of the minute amounts added to a monitored city water system. The occasional problem is in a private well where high levels of fluoride may occur naturally. Private wells should be checked regularly, and for more than fluoride content. The great amounts of pesticides and other chemicals used by farmers and state and federal governments have resulted in the pollution of many rural wells.

What about swimming in polluted water?

If the health department has posted signs indicating the water is polluted, don't risk your health by swimming there. Polluted water is usually contaminated by bacteria and viruses from raw sewage. This happens when a sewage treatment facility overflows or when a heavy rain washes effluent off the streets and fields into lakes and the ocean. Such diseases as hepatitis and severe gastrointestinal upsets can result.

Does a computer terminal give off radiation that might affect health?

The amount of radiation that escapes from a computer terminal has been measured as being well below the acceptable standards, much less than that from many other household appliances. There may be other factors associated with the use of computers that could be of concern. The constant noise of a cooling fan or the disk drives can induce stress.

Extended hours at the keyboard can cause back, neck, shoulder, and wrist pain. Sitting in a comfortable chair that can be adjusted and having the computer screen at the proper height can ease some of these problems. Taking regular breaks and stretching can reduce muscular tension.

Proper lighting, so that there is no glare on the screen, can reduce eyestrain. Recent research indicates that long hours spent looking at a video display terminal may affect the eye's ability to shift focus. Taking regular breaks can also reduce eyestrain and minimize your chances of getting a headache. You should take a 10-minute break after 50 minutes at the terminal in order to reduce physical tension. See an optometrist if you think you are suffering from headaches or eyestrain caused by long hours at a computer terminal.

Can X rays affect health?

Definitely. Too much exposure to radiation from excessive X rays is linked to various types of cancer. However, the amount of radiation shown to be dangerous is thousands of times greater than the amounts used in diagnostic X rays. Excessive amounts were used diagnostically many years ago, before radiation standards and controls were set, or as part of outdated practices (such as using radiation to treat acne). Now, high-dose radiation therapy is used to treat some cancer. The federal safety standard for occupational radiation exposure is 5,000 millirem. The average American is exposed to 360 millirem a year from a variety of sources, such as the sun, radon, and X rays. Each chest X ray is 15 to 20 millirem.

It is a good idea to avoid all but the most necessary X rays. All X-ray machines and operators are strictly regulated and licensed. If a physician orders X rays for diagnostic purposes, you are well within the acceptable amounts of radiation exposure. Radiation specialists have found that one chest X ray equals the amount of radiation you would receive from spending a few days at the beach or at high altitude. X rays are an essential diagnostic tool. If you have questions about your exposure, discuss them with your physician.

Always wear a lead apron to protect yourself from excessive exposure when getting X rays. It is particularly important to protect the gonads from exposure because of their susceptibility to damage from radiation.

Routine chest X rays in healthy individuals are no longer recommended. Pregnant women should avoid all X rays because of the severe effect they can have on the developing fetus. If you are pregnant, or think you might be pregnant, be sure to tell your physician before any X rays are ordered.

Is radon a threat to health?

Radon is an indoor pollutant that researchers suspect is responsible for at least five thousand cases of lung cancer a year in the United States. It is a naturally occurring radioactive gas that is released by the breakdown of uranium deep inside the earth. It is invisible and odorless and can build up inside a home or other building. Because it is heavier than air, it can displace the regular atmosphere, particularly affecting subterranean basements and garages. Radon may also be released from some building materials such as concrete.

A recent estimate holds radon responsible for 55 percent of the radiation exposure in the United States. Radon can be detected by a simple and inexpensive test. Get in touch with your state EPA for a list of laboratories that perform the test.

Can food be a threat to health?

There are a number of health risks associated with our diet. They can be categorized into five areas. Ranked from the greatest danger to the least by the standard risk criteria of severity, incidence, and quickness of onset, they are the following (examples are in parentheses):

  1. Microbial hazards (salmonella infections, botulism, hepatitis, staphylococcus infections, trichinosis, shigella infections, and cholera)
  2. Nutritional hazards (malnutrition, scurvy, pellagra, rickets, goiter, beriberi, megavitamin poisoning, trace element poisoning)
  3. Environmental contaminant hazards (arsenic, mercury, cadmium, lead, PCBs, DDT, other pesticides)
  4. Naturally occurring hazards (toxins such as oxalates in spinach, glycoalkaloids in white potatoes, mycotoxins in grain mold, poisonous mushrooms, paralytic shellfish poison)
  5. Additive hazards in foods and colorings (monosodium glutamate poisoning, cancer from dyes and nitrites)

Most food poisoning is the result of eating improperly prepared or stored food. To protect yourself from these hazards, it is important to thoroughly cook chicken and meats such as pork. Until they have been washed with soap and hot water, the utensils and cutting boards used to prepare these items should not be used to prepare other foods. Washing your hands before preparing food and after going to the bathroom is an important procedure for preventing the spread of disease.

Leftover cooked items should be covered and put in the refrigerator within 4 hours after use. Allowing them to sit on the counter for hours or overnight greatly enhances microbial growth. The refrigerator temperature should be set at 40 degrees or lower.

Washing fruits and vegetables thoroughly can remove pesticide residues. Do not eat or cook any fruits or vegetables that have not been thoroughly washed.

Most nutritional imbalances can be avoided by a balanced diet. Nutritional hazards can result from excessive consumption as well as deficiencies. (Review chapter 1 for an overview of proper nutritional practices.) Taking megadoses of vitamins and minerals can be hazardous to your health; the only research that has indicated there may be a benefit from this concerns vitamin C. A recent study showed that the severity of a cold may be reduced by taking 1 to 2 grams of vitamin C daily. However, this may cause diarrhea, and if symptoms of gastrointestinal upset develop, you should stop its use.

Should I eat so-called organic foods?

There is no nutritional advantage to eating organically grown food, though eating food that is free of pesticides and other chemicals is certainly a worthwhile goal. Many people believe that eating "organic," or "health," food is going to protect them from cancer and from chemical poisoning. It is not safe, however, to assume that foods labeled organic are completely free of additives, chemicals, and pesticide residues. Only eight states have legal standards for what are called organically grown foods. Even though farmers may not use pesticides on their crops, they may have had no control over what happened to the land 5, 10, or 20 years ago, and they certainly have no control over the water they use to irrigate the fields. Chart 11.2 shows how to minimize the residue from pesticides.

It would be unwise and unnecessarily expensive to assume that healthful food is found only in health food stores. Often the prices are high, and health food stores are sometimes the source of many quirky nutritional theories that may not be in the best interest of your health.

Often these stores are also eager to sell you expensive vitamin and mineral compounds to supplement your diet. In many ways these are similar to the additives that are put into food directly because a certain nutrient may be lost in processing. However, as discussed under the preceding question, consuming vitamins and minerals by the handful can result in serious imbalances and illness. Many food fads can also result in serious imbalances. For example, eating large amounts of kelp or iodine can lead to serious thyroid disturbances and the development of goiter.

The consumption of "raw" dairy products is responsible for many cases of food poisoning each year, caused by organisms that would ordinarily be killed by the pasteurization process. These are not "health" foods.

Are food preservatives and additives health threats?

Some preservatives have been associated with the reduction of certain types of cancer; BHA and BHT are two that have been connected to reduced stomach cancer rates. Other preservatives may potentiate cancer or cause potentially life-threatening allergic reactions. Nitrites and nitrates, used to preserve such foods as bacon and sausage, can be transformed into nitrosamines after cooking. Nitrosamine is a known carcinogen. Allergic reactions to monosodium glutamate (MSG), a common flavor enhancer, and to tartrazine (yellow dye number 5) are well documented. A number of food colorings have been banned by the Food and Drug Administration (FDA), including carbon black, FD&C Red No.1, FD&C Red No.2, FD&C Red No.4, FD&C Green No.2, FD&C Orange No.1, FD&C Violet No.1, FD&C Yellow No.2, and FD&C Yellow No.3.

What are the dangers to health from the process of irradiating food to preserve it?

This process leaves no radiation in the food. Despite the terrifying concept of the ingestion of radioactive food, it may be safer than treatment with some of the chemicals now used for preservation. Irradiation of food at radiation levels 100 times greater than those used in the process would still leave no radioactivity in the food.

However, radioactivity in any form has hidden dangers associated with accidents and waste disposal. There is also the possibility that radiation-resistant microbes will develop. The process may also change the taste and texture of the food.

Can listening to rock and roll music affect health?

No more than listening to classical music. Much depends on the volume. Too much noise can affect your health by causing hearing and other damage. Noise induces stress, and high levels (over 80 decibels) can induce hearing loss. These high decibel levels are more common at rock and roll concerts than at symphony concerts.

The noise levels at rock and roll concerts and sporting events can reach 120 decibels and possibly higher. The pain threshold is about 120 decibels. The maximum industrial noise level that the law allows over an 8-hour day is 90 decibels.

Recently lawsuits have been filed against rock musicians for subjecting their fans to extreme sound levels that may have caused permanent hearing loss. This can happen. Wearing ear-plugs to a rock and roll concert may protect your hearing.

Headphones are also responsible for hearing damage. Flipping the switch when the volume is already cranked up may give you a blast that can suddenly damage the very sensitive parts of the ear and cause irreversible hearing loss.

But even the quiet dripping of a faucet can drive you crazy, so sometimes the decibel level isn't the only factor to be concerned with in noise pollution. Any continuous noise can cause stress and thus increase blood pressure, alter hormone levels, and constrict blood vessels. We don't really know why, but persistent stress can precipitate the disease process. If noise is an ingredient in your environmental pollution, you should take steps to eliminate it. (See Emotional Well-Being and Preventive Medicine for more information on reducing stress associated with noise pollution.)

How can overall pollution be reduced?

A simple way for the individual to help reduce pollution is to recycle aluminum, plastic, glass, and paper. Little time and effort are expended, and manufacturing wastes are greatly decreased. A major polluter whose use we can limit is the automobile. Walking or riding a bike whenever possible is not only healthier, it saves money while it lessens pollution. Carpooling or using public transportation can give our overstressed environment a break.

Become politically active on environmental issues. Vote for candidates who express their concern by sponsoring legislation to clean up the environment. Boycott the products of companies that are known polluters. Below are some other suggestions:

Our inability to deal with environmental hazards should be of concern to everyone. In many ways these problems are coming home to roost and are reflected in increasing rates of cancer, shortened life expectancy, premature death, and increasing incidence of disease.

The problems are also reflected in the dirty brown clouds that hang over our cities and in the pollution that muddies our waters. We must realize that environmental pollution is not an impending condition to worry about in the future. We are already in the middle of the crisis, and evidence of our folly surrounds us: the destruction of the ozone layer; the greenhouse effect; and the thin eggshells caused by DDT, which is still threatening the survival of so many bird species by its use in other countries. We must realize that when our actions are capable of annihilating an entire species, we are placing the human race on the endangered list as well.

Every year new ecological disasters are uncovered from events of 10, 20, and 30 years ago. It remains to be seen if humankind has the technology, the capability, the money, or even the inclination to try to recover what we may have already destroyed. Cleaning up the environment is going to be possible only with a fundamental change in the way we live our lives at the individual level. There is little indication that we can count on our government or our industries to protect us. It will take a concentrated, grass roots effort by all of us to preserve the planet Earth, and in doing so, save ourselves.