Throughout the centuries, there have been many benefits brought by chemistry to our daily living. Two significant contributions made by chemistry towards our lifestyle is the protection of our health and hygiene. The purification our water by process of chlorination, dental cleanliness from toothpaste, sterilisation, the control and the cure of disease are all a part of daily living discovered and created by chemistry. These discoveries make up a major component for the protection of our health and hygiene and are vital for the future existence of mankind.
The ideal water for humans is hard water. Hard water is healthy as it consists of calcium, Ca2+, and magnesium, Mg2+, ions. Ca2+ are needed in the formation of bones and are important in the clotting of the blood and regulating the heart beat. Mg2+ are needed for making protein and for passing impulses along nerve cells. The chlorination of water for drinking makes the water safe because it rids it from the diseases which can be transmitted through it. However, ideal water isn’t necessarily pure water. Pure water is expensive to produce, is tasteless and lacks in magnesium ions. Magnesium ions reduce the incidence of the hardening of arteries and therefore is used in the protection against heart disease. The gas chlorine, Cl2, is most useful to purify water. Chlorine kills viruses and bacteria because it reacts with water to produce hypochlorous acid.
Cl2 + H2O HCL + HCLO
hypochlorous
acid
One aim of chemistry is to maintain dental cleanliness. Bacterial infection of the tooth structure is called dental caries. The bacteria convert the sugar in our diet, particularly sucrose, C12H22O11, to a glue to stick themselves to the tooth surface. Acids such as acetic, propanoic and lactic are also produced. These acids cause the calcium phosphate in the tooth enamel to dissolve. The reaction is:
Ca3(PO4)2 + 4H+ Ca(H2PO4)2
soluble calcium
dihydrogen
phosphate
When the enamel weakens, the organisms can then invade the tooth which may eventually be destroyed. The fluoridation of water supplies is beneficial as the hydroxide ions in the tooth enamel are replaced by fluoride ions. It has been suggested that the fluoride ions slow down the growth of bacteria. The aim of toothpaste is to clean and polish the teeth. It basically consists of a mild abrasive, usually powdered calcium carbonate and a small amount of soap. These solids are suspended in a liquid, usually glycerol, and dyes and flavourings are added. The addition of fluoride ions, F-, from sodium fluoride, NaF, is beneficial for children as the fluoride ions will help form a stronger enamel while their teeth grow.
Sterilisation is the destruction of bacteria and is an essential part in the fight against disease. Heating is used to kill bacteria and the cooking of food is an everyday example. Milk is partially sterilised by heating it to about 800C and maintaining the temperature for about 16 seconds. This process is called pasteurisation and ensures that all potential harmful bacteria are destroyed within the milk. Chemists have produced many bacteria killing chemicals and the use of these has saved many lives. The first of these chemicals was a dilute solution of carbolic acid, C6H5OH. In 1985, a surgeon named Joseph Lister began sterilising surgical wounds with this solution. The number of deaths in his wards decreased because of this practice. Two main solutions used to kill bacteria in the home are antiseptics and disinfectants. Disinfectants are stronger than antiseptics and are too harsh, irritant or toxic to be used on the skin. It is usually used to clean or sterilise objects such as surgical instruments. Antiseptics are used on the skin, either before surgery or on cuts and bruises, and prevents sepsis which is the destruction of the tissues by bacteria.
One aim of medicine is to control disease with the use of chemicals. Chemicals, or drugs, are made from natural causes such as plant or animal extract, or are made in the laboratory. The most successful synthetic drug in the world today is called acetyl salicylic acid, or more known as aspirin. It is made from salicylic acid, a disinfectant, and acetic acid.
Aspirin is anti-inflammatory, meaning it reduces swelling, redness, relieves arthritis and is effective against stroke. However, if used too much side effects such as internal bleeding of the stomach occur. Aspirin is also known as an analgesic as it is a pain killer. Three types of pain killers are strong analgesics, local anesthetics, and sedatives. Strong analgesics are complex nitrogen compounds isolated from opium such as morphine (C17H19NO3.H2O). Local anesthetics reduce the sensitivity of nerve fibers to reduce pain such as cocaine (C17H21NO4). Sedatives are drugs which reduce tension and anxiety such as codeine (C18H19NO3.H2O).
Another aim of medicine is to cure disease. The use of chemical agents to destroy infectious organisms, or diseases, without destroying the host is called chemotherapy. Before 1900, only three chemical remedies were known: chinchona bark for malaria, ipecacaunha for dysentery, and mercury for syphilis. Very significant types of drugs related to chemotherapy are drugs containing sulfur, or sulfa drugs. Sulfa drugs are dyes that are specifically lethal to harmful microorganisms. Protonsil was the first sulfa drug. It breaks down in the body to sulfanilamide, which is effective in destroying streptococci.
Bacteria need para-aminobenzoic acid to make a vitamin called folic acid to grow, and as the structure of sulfanilamide is similar to para-aminobenzoic acid, the bacteria can’t distinguish between the two chemicals. The bacteria take in the sulfa drug instead of the para-aminobenzoic acid and die. Luckily, humans don’t need para-aminobenzoic acid to make folic acid so they are unaffected by sulfa drugs. Compounds related to sulfanilamide were tested: sulfapyridine was effective against pneumonia and sulfathiazole saved the lives of many wounded soldiers during World War II.
There are many contributions made by chemistry that deal with our lives. The simple health and hygiene of a human, in particular, consisted of many hours of hard and dedicated work and research by chemists. The purification of our water by chlorination, dental cleanliness by toothpaste, the sterilisation of a cut, the control of disease by aspirin, and the cure of disease by chemotherapy have all contributed to our livelihood and our health. Whenever we drink tap water, brush our teeth, dress a wound, have an aspirin for our headache or drink medicine we are using these contributions made by chemistry. Without these contributions, we would not be living in the clean and healthy lifestyle that we live in today.
BIBLIOGRAPHY
Merlin Internet http.//www.amcal.com
World Book Encyclopedia Volume 13 M pp.299-306
George W. Beadle
Chemistry 2000 Chapter 22 – Health & Hygiene pp.367-378
Forside
