The Principles of Green Chemistry
In my unit, students will learn the 12 principles of Green Chemistry. 2 1 Since I am teaching reading and science to my second language learners, I will only focus on Principles One, Two, Three, Four, and Six. These principles will help them understand the importance of water to all living organisms and how to keep drinking water clean and safe. Most of my students live in apartment dwellings. The cost of water bottles in plastic containers is too expensive for them. Using tap water will lessen the cost of buying drinking water and will minimize the use of plastic bottles which contains chemicals that are hazardous to their health.
First Principle
Green chemistry's first principle states that it is better to prevent waste than to treat or clean up waste after it is formed. To integrate reading with science content, the students will read "The Lorax" written by Dr. Seuss. The Lorax warned the Once-ler to stop cutting down the truffula trees but the Once-ler refused to listen. As a result of his greed, the beautiful place where the trufulla trees grew, where the swomee-swans lived, where the barbaloots played and ate trufulla seeds, and where the humming fish swam became so polluted that everyone left.
Water pollution is caused when humans add chemicals into water that cannot be filtered out. There are many chemicals on the market and the government has identified the toxic chemicals. They are harmful to humans, plants and animals. There are two popular manmade products, namely the detergent and softener, which many people use to keep their clothes clean. These products contain phosphates, neurotoxins and carcinogens that contribute to groundwater pollution. Detergents contain phosphates. Phosphates cause the water foaming action every time we do our laundry. Washing and rinsing clothes using detergents allow chemicals to go into the water supply.
Even the fabric softener that makes our clothes smell like pine, jasmine, and lavender contains chemicals that have high toxicity. Every time we rinse our clothes, water goes through the pipes and the sewage. Fabric softeners change the detergent's negative electrical charge back into a positive charge thereby reducing static. The film coats, fluffs and scents the fiber. Liquid softener contains neurotoxins and carcinogens. These toxic chemicals are dangerous to human health because they affect our nervous systems. Neurotoxins and carcinogens are slowly released when we wear our clothes and use our towels and our sheets. Every time we tumble dry our laundry, we release the toxins into our environment through the dryer vents. When we use fabric softeners, the clothes increase their flammability because the materials become thinner. The softener slowly takes away the fabrics' layers. The unit will teach the students that although some chemicals smell good, they are hazardous to human health and to our water. Our clothes will still smell clean if we use an alternative to fabric softener, such as dryer balls.
The use of chemicals in the industry is high. The American Chemistry Council tabulates yearly the United States top 100 basic chemicals. In 2000, the amount of the top 100 chemicals produced was a total of 502 million tons as compared to the 1990 figure of 397 million tons. 2 2 These chemicals are necessary to make all kinds of medicines, plastics for making good soap/detergent, clothing, and other consumer products that will improve the quality of life. However, there is no place to dispose of waste products. For many years, people have been disposing waste products away into rivers and lakes. As a result, many water sources have become polluted. There are thousands of man-made lagoons where waste is disposed of. During the water cycle, the water evaporates from these lagoons, and the chemicals become more and more concentrated. Since the bottoms of the lagoons are sand and dirt, these chemicals are absorbed slowly into the ground water.
The EPA informs us of drinking water contaminants. 2 3 Cryptosporidium comes from human and animal fecal waste. When a person ingests water that contains this contaminant, he/she gets gastrointestinal diseases. Coliforms are naturally present in the environment as well as in feces. Viruses are found in human and animal fecal waste. One can get gastrointestinal diseases from them. When the water gets cloudy, turbidity is tested. It indicates water filtration effectiveness. Parasites, bacteria and some microorganisms cause nausea, cramps and headaches. There are other contaminants such as disinfectants, inorganic chemicals, organic chemicals and radionuclides. All of these contaminants affect the health of humans who ingest water.
Chemicals that get into the ground water cannot be removed easily. If groundwater moves, the water is purified naturally by the soil; if it does not, the toxic chemicals stay. The impurities remain underground. Sometimes impure water can be purified by pumping it to the surface, treating it and putting the water back in the ground. This water purification process is very expensive. The best thing to do is not to pollute groundwater.
What are the different sources of water?
The source of water is not known to everyone. Water that flows from the faucet, have two sources. Surface water comes from the water in rivers and lakes. Groundwater comes from wells. Most water in the United States comes from ground water. The agency that provides us information online is the Environmental Protection Agency. A large percentage of the US population get their water from the groundwater community supply and the rest of the population gets water from private wells, camp grounds and resorts. s. About a large number or percentage of the water sources come from the surface and the other percentage is from wells. The taste of ground water is different from surface water. There is a taste of metal in ground water and it contains minerals. In some places, the surface water has a musty taste and looks cloudy. The look and taste of water depends on where it is coming from.
The next green chemistry principle will be a combination of principles two and three: synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product; and wherever practicable, synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment. The children's literature applicable to this science
content lesson is S is for Save the Planet. The book contains 26 poems and practical ways to keep the Earth green. The solution given for the environmental issues is suitable for children of all ages.
I can incorporate in this lesson the different ways of purifying drinking water from the tap. One way of doing it is by simply boiling it. Drinking water in the US is the safest water supply in the world. Water is frequently tested for human consumption. In most places tap water is safe to drink. The water source is well tested. The public is informed of their water supply and when there are contaminants in the water suggestions are given on how to purify it or not to drink the water at all. When water flows through the rivers and gets collected in aquifers, the contaminants are low and not hazardous to human health. The US Environmental Protection Agency (EPA) explains that the public water suppliers and well owners must monitor their water supply. There are standards for keeping the water supply safe. EPA has named 90 contaminants to set their standards and these contaminants are monitored in drinking water. Therefore, drinking tap water is safe.
There are only a few instances when water is unsafe. This happens when there are treatment problems or weather conditions are bad. For example, during a hurricane the flood water is most likely to contaminated water that flows to the rivers and the wells. The contaminants are not a threat to the public health. Water will be treated to remove those contaminants. Bacteria and viruses may also contaminate the water. It might cause the following illness: vomiting and diarrhea for some people. If the water treatment does not meet standards, the water supplier must inform the public. The water suppliers are required by the law to notify the consumers. EPA water standards protect children and adults from drinking or using unsafe water.
The fourth principle of green chemistry is all about designing chemical products to preserve efficacy of function while reducing toxicity. The book that I will use to integrate reading and science is Song of the Water Boatman & Other Pond Poems. The students will read this book to find out what would happen to a drying pond and its inhabitants. To sustain Earth's water, we must avoid chemicals that affect humans, plants and animals. In this story, when the pond dries out the living organisms will perish or disappear.
Arsenic, fluoride, and water are toxic to human health. When we drink water with these contaminants we are taking water into our system with poisonous chemicals that will affect some parts of our body like the colon. Arsenic is a heavy metal. It is gray or yellowish. Arsenic is a deadly and poisonous element. When it enters our blood stream arsenic is difficult to detect. Arsenic is considered as a metal and a non-metal. When industrial sections dispose of arsenic improperly it goes into the water-ways. Arsenic is so toxic that it causes cancer. Poisoning takes place in the body and results in death. Multiple organs in the body fail. The affects are lethal. A large amount of arsenic is dangerous for humans as well as animals. The human body can ingest a small amount of arsenic because it is essential. Seafood such as shrimps and crabs are sources of arsenic.
Fluoride is classified as a non-metallic element. Its color is pale yellow or green. Fluoride is added to water for teeth protection. Some think that it prevents tooth decay. That's why fluoride is commercially found in baby formula, bottled water, tooth paste, aluminum foil and many more. Another form of fluoride is Teflon. Teflon is known for its non-stick coating to pots and pans. Fluoride is an element that could take an electron from almost any atom and form other compounds. However, a pollutant is created when fluoride is in CFC (chlorofluorocarbons). CFCs are used in sprays which have done so much damage to the ozone layer. This chemical could be toxic to human, plants and animals health.
Chlorine is a green and nonmetallic element. It is a toxic gas. According to history, chlorine was used as a weapon in World War I. People that inhaled this toxic chemical died. These days, chlorine is often used in household cleaners. It is a popular chemical because it kills bacteria, especially those found in toilet bowls. It could also be used to fight cholera and typhoid fever when added to purify drinking water. Chlorine is used to treat our drinking water supply. In doing so, our water supple becomes potable and safe. Swimming pools use chlorine to keep their water bacteria free. However, it becomes toxic to humans, plants and animals when the element is added to the pesticide DDT and also when used in CFC products.
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