A Quick Lesson in Chemicals

Catfish deformed by DDT Chemicals, for the most part, have made our lives much easier. Because of chemicals , we have medications, ways to preserve our food, less insect pests, and even soap. Our bodies are composed of chemical elements like carbon and nitrogen. However, chemicals can also be harmful. Many food additives cause cancer. Mercury is a good thing when it is in our thermometers, but not when it is in the fish we eat. This section is a short summary of chemicals that have become well-known out of concern for their effects on the environment. In Vietnam the United States used agent orange to defoliate rainforests, exposing the enemy. Agent Orange (contains dioxin as well as other toxic substances) An agricultural chemical that has been used to kill weeds and brush. AO works as a defoliant by causing plants to lose their leaves. In the Vietnam War, the US used this substance to strip down jungle areas in order to deprive enemy forces of hiding places. Some of the reported side effects after exposure to AO include cancer, nervous system disorders, stomach problems, headaches, and psychological disturbances. These symptoms were noticed in both North Vietnamese and American veterans. It is controversial as to whether or not AO is completely responsible for these effects. Alar (the chemical daminozide) Alar was used by orchards to cause apples to ripen all at once. This way they could be harvested at the same time. It also made the apples look colorful and appealing. The Environmental Protection Agency (EPA) suggested in 1989 that the consumption of alar-sprayed apples could increase the risk of cancer. Alar was not banned because the evidence was not conclusive. The public stopped buying apples when an environmental group cited a study that children were at risk due to consumption of more apple products than adults. Alar was removed voluntarily by both apple growers and the manufacturers. Arsenic This chemical element is used in many products. Some hair products like dyes and certain medications may contain small amounts. The compound, arsenic trioxide is the key ingredient in rat poison, herbicides, and pesticides. Arsenic is used to remove color from glass and can be found in wood preservatives as well as some pigments. Arsenic is a carcinogen (causes cancer) and poisoning is a problem. This element often finds its way into groundwater supplies when used agriculturally. This is indeed alarming especially when it turns up in wine or fruit juice. Asbestos Asbestos for the most part has been invaluable to mankind. Because it is resistant to acid and heat, it can be utilized in very beneficial ways. Asbestos can serve to insulate electrical equipment, buildings, and the hot water pipes inside them. It is probably best known for its use in fire-resistant materials especially clothing. The downside of this useful mineral occurs when people inhale the fibers or dust. Firefighters entering burned buildings where asbestos has been released into the air and workers who tear down buildings are at risk. Without a doubt, people who are employed in factories or mines that use or process asbestos are very susceptible to its harmful effects. Asbestos primarily affects the lungs and promotes lung disease. One such disease is asbestosis which is characterized by breathing difficulties of great severity. Other health problems include mesothelioma (a rare fatal lung cancer) and stomach cancer. The use of asbestos is now strictly regulated; yet, it appears that we are all exposed to it even in small doses. Whether or not this is enough to cause health risks in the average person is still controversial. Some forms of asbestos, particularly those used in buildings are not as dangerous as others according to experts. Carbon Monoxide (CO) Photo by Diana Martin CO is an odorless gas that is extremely toxic. It is produced in the exhaust of cars and trucks. (This should not be confused with carbon dioxide which is what we exhale during normal respiration.) CO does, however, affect breathing. If a person inhales CO, it combines with the hemoglobin in the blood. (Hemoglobin is meant to carry oxygen). The hemoglobin then carries CO through the blood and thus deprives the person of oxygen. If enough CO is inhaled, the person will die from lack of oxygen. With the vast number of cars and trucks on the roads today, people are exposed to higher levels of CO. Chlorine (CO) Like asbestos, chlorine has many valuable uses. It kills bacteria in swimming pools, sewers, and drinking water. Chlorine by itself has an irritating odor and is a poisonous gas. Environmentalists are concerned about this gas because it is often mixed with other pollutants such as DDT, PCBs, dioxin, and CFCs. Chlorine is also found in polyvinyl chloride (vinyl plastic). Inhalation is toxic. Chlorofluorocarbons (CFCs) Fire Extinguishers are among many common objects that emit CFCs. Photo by Diana Martin CFCs are gas mixtures composed of a) chlorine, b) hydrogen (the element which combined with oxygen produces water), c) carbon (an element that is normally found in living plants and animals. YOU are made of carbon, along with some other elements) and d) fluorine (another poisonous gas). CFCs are believed by scientists to destroy the ozone layer (a form of O2 that protects us from the dangerous UV rays of the sun). Most experts agree that the destruction of the ozone layer will result in climate changes. These changes will ultimately harm life on earth. CFCs are found in many common objects including fire extinguishers, spray cans (aerosols), air conditioners, solvents, and refrigerants. CFCs are also formed when plastics are being manufactured. DDT (Dichlorodiphenyltrichloroethane) DDT is an insecticide containing chlorine. It was used extensively in the 1940s and 1950s until scientists started becoming alarmed at the long term effects it had on other living organisms as part of the food chain. For example, DDT killed animals that ate leaves which had been sprayed. If DDT was present in a water supply, it contaminated microscopic organisms. The organisms in turn were eaten by fish. The fish eventually died and were then eaten by birds. The birds died and so on. Currently, the use of DDT is banned in the US and at least 40 other countries. Unfortunately, it is still in use in areas such as India where between one and two million people die from malaria each year. The problem with this, besides longlasting toxic exposure, is that the fast-breeding mosquitoes develop immunity to its effects. Even more unfortunate is that people (including here in the US where its use is banned) are still exposed to DDT. It remains in the atmosphere and is present in rain and snow. It is a hard choice for some countries to make---knowingly adding toxins to their environment or allowing people to be exposed to malaria. Dioxin The name dioxin refers to a family of compounds (approximately 100) that are formed when paper is bleached to make it whiter or during the production of pesticides and herbicides like Agent Orange. While there are variances, dioxins are commonly known to be among the most toxic of chemicals. As stated in the Agent Orange section, there are opposing viewpoints about how much dioxin affects humans. Many people (such as veterans exposed to AO) do exhibit health problems after exposure. Others are not convinced that these effects are the result of dioxins. Dioxins have been found in the flesh of bottom-dwelling fish caught in the Great Lakes. The USFDA issued guidelines on what (how much) is safe to consume and how much isn't. One problem associated with these toxins is how to dispose of them. Again, it is controversial. One side (EPA and other organizations) feel that burning the wasted dioxin is the best solution. Environmentalists do not want the waste burned because this causes harmful fumes to be released into the atmosphere. The problem of how to dispose of toxic wastes is not just limited to dioxin. Lead Lead is a metal that has been utilized in many products such as paint, batteries, dyes, water pipes, pesticides, medications, and in nuclear reactor shields. In dentistry, lead aprons protect the rest of the body from radiation during the filming of xrays. Lead was previously used in pencils. Today, however, pencils are made of graphite. Lead is a very toxic substance. It causes brain damage, hearing problems, and decreased coordination because the nervous system is seriously affected. If lead is inhaled as a result of incineration, its fine particles enter the lungs and eventually the bloodstream. In the past, lead poisoning in children gained a great deal of attention. Children's bodies are affected much more adversely than adults because they are smaller and their nervous systems are not completely developed. Many were exposed to the dangers of lead by chewing on lead-painted furniture or windowsills. Others drank water that passed through lead pipes. Today, children are tested for lead poisoning prior to entering school. Mercury Mercury is probably best known for its use in scientific equipment such as thermometers and barometers. Mercury can also be found in latex paint and dental fillings. This metal tends to build up in the body eventually causing neurological problems. In the 1950s and 1960s, residents of a small village in southern Japan called Minamata ate fish which contained high levels of mercury. The people got very sick and many died. Symptoms of the mercury poisoning included deformed children, children born without brains and loss of control of arms/hands and legs. The fish became contaminated with mercury when a chemical plant dumped its waste into the village's bay. Today, there are limits (originally set up by the FDA in 1969) on the levels of mercury that are acceptable in food sources. Swordfish has attracted a lot of attention. In the past, this food fish has often exceeded the recommendations. Swordfish coming into the country is now kept until adherence to the requirements is established. Nitrogen Dioxide Nitrogen by itself is essential to life on earth. This element is a gas that forms most of our atmosphere. Nitrogen dioxide, however, is another byproduct from vehicle exhaust and is generally inhaled. Inhalation irritates the lungs and promotes viral infections as well as bronchitis and pneumonia. Nitrogen Fertilizers Again, nitrogen is an element that is critical for life. Plants in particular, are dependent upon nitrogen to produce protein and for overall health. However, when nitrogen (in a fertilizer) is added to soil, it becomes nitrate. Nitrate then seeps into groundwater supplies. Nitrate at high levels may produce sickness. Some scientists claim that birth defects are a possible side effect to high levels. Regulations are in place to determine how much nitrate is safe in water. Yet, many areas in the world still contain harmful levels. Ozone The Ozone layer shields the earth from destructive UV rays. From "Investigating the Ozone Hole" By Rebecca L. Johnson 1993 Ozone naturally is part of the upper atmosphere. The ozone layer is about 7 to 15 miles above the surface of the planet and it protects life on earth from the UV rays of the sun. Unfortunately, ozone produced at ground level is a dangerous pollutant. It damages plant life and contributes to breathing ailments such as asthma and other forms of lung disease. Ozone can also worsen heart disease. Ozone on earth is created from vehicle exhausts. When the energy from the sun causes nitrogen oxides (a by-product of cars and power plants) to react with hydrocarbons (produced by industrial processes and vehicle engines), ozone is formed. Ozone along with fog, smoke, and other pollutants make up smog. PCBs (polychlorinated biphenyls) PCBs have a variety of different uses. They are found in adhesives and paints to promote flexibility, as insulators of electrical transformers and as receivers of electricity in household appliances. Unfortunately, PCBs are formed when plastic wastes are burned and then introduced into the atmosphere by factory smokestacks. The problem with PCBs is that they are highly toxic and do not break down easily. Despite the fact that these chemicals are no longer created, millions of pounds are still present all around us---in our water, in the air, and in landfills. Researchers have shown that PCBs are stored in body fat and can cause cancer. In the case of the bald eagle, PCBs have greatly contributed to their decline by being present in certain food fish. PCBs have been found in coho and chinook salmon as well as bottom-dwelling freshwater species. Experts estimate that it will be at least 20 years before the PCBs on earth will finally begin to break down. Factories have produced many items that have impoved our standard of living. However, disposing of some of the products and by-products have cost us dearly. Photo by Diana Martin Polymers Natural polymers are composed of proteins and starches. Synthetic (or artificial) polymers are man-made and cause several problems. Synthetics contain toxic substances which may run into groundwater supplies if present in dumps. If they are burned, deadly toxins are released and pollute the air. Workers that are employed in factories manufacturing these substances are at risk if these toxins are inhaled. Synthetic polymers are present in many well known products such as styrofoam, spandex, nylon, Teflon, and polyester. Sodium nitrite Sodium nitrite is a salt often used as a preservative in foods such as bologna, bacon, smoked fish and ham. The problem with this substance according to researchers, is that it combines with natural stomach chemicals to form nitrosamines. Nitrosamines are WELL-KNOWN carcinogens that are also present in cigarette smoke. Sulfur Dioxide A gas which when released into the atmosphere (much like nitrogen dioxide) greatly contributes to our acid rain problem. Sulfur dioxide can occur naturally when organic material decomposes or as a by-product of volcanic activity. Unfortunately, our high rate of burning sulfur, oil, natural gas, and coal for energy increases the amount of this toxin in the air around us.