————————————————- Impacts of Applications of Chemistry on Society and the Environment ————————————————- Open Ended Investigation Madeline De-Sanctis INTRODUCTION From the earliest times, Chemistry has played a pivotal role in the advancement and enrichment of civilization, although sometimes it has also caused harmful and occasional long-reaching catastrophic effects on the environment.
The importance of this sphere of science can be demonstrated by the fact that entire periods in history were named the Iron Age and the Bronze Age, according to the level of chemical endeavor of that time. The content in this report will comment on the various implications of science on society and the environment, such as the use of CFCs, the use of soaps and detergents, shrinking world resources, eutrophication, heavy metal pollution and poisoning, and the role of chemists.The information in this report was obtained from a wide variety of resources, as in the bibliography, which have each been assessed for their reliability and validity.
1. CHEMISTS In todays environment scientists can choose to specialise in numerous fields of chemistry. There are various reasons for this, including the advancement of scientific knowledge of the earth that allows scientists to research things that have never been researched in previous times. There are three broad areas in which chemists work: teaching, industry and research.
Within these areas are various divisions of chemistry, each which have separate facets of their own. The Royal Australian Chemical Institute (RACI) states that there are thirteen divisions of membership, some of which include analytical chemistry, environmental chemistry and electrochemistry. Collaboration is very important in the field of chemistry.
The fact that chemistry has many branches means that chemists will have expertise in different areas. A chemist cannot perform in isolation, simply because they are not able to be an expert in every field of chemistry.It is essential that chemists work collaboratively and communicate regularly with each other, exchanging different viewpoints about problems. Forensic Chemistry Forensic Chemistry is the application of chemistry to the investigation of a crime. Forensic chemists analyse evidence that is brought in from crime scenes and reaches conclusions based on the processing of that piece of evidence. A forensic chemist does not individually seek to solve a crime, yet seeks to identify and characterise the evidence that will in the long run be critical to solve a crime.Crimes investigated by a forensic chemist may be crimes against an individual or against society.
A forensic chemist usually works in a laboratory, and will often work with extremely small quantities of material, such as hair samples and swabs of blood. A major part of a forensic chemist’s skill is the ability to use techniques of separation and analysis used in analytical chemistry. Forensic chemists apply separation and analytical techniques by using various methods of extracting evidence, for example chromatography and electrophoresis.
A chemical procedure used by forensic chemists is chromatography.Chromatography is a means of separating the components of a chemical mixture. The theory of chromatography has as its basis on the chemical principle that chemical substances have a tendency to partially escape into the surrounding environment when dissolved in a liquid or when absorbed on a sold surface. The three different types of chromatography commonly used in the laboratory include: Gas Chromatography (GC), High-Performance Liquid Chromatography (HPLC), and Thin Layer Chromatography (TLC). Forensic scientists are extremely beneficial to society as they help to solve crimes and in turn make society safer.
Forensic chemists can be classified into several subgroups, such as forensic pharmacists (who study medicinal drugs) and forensic toxicologists (who study poisons), and can specialise in solving specific types of crime such as arson, forgery and poisoning. 2. SOAPS & DETERGENTS Cleaning products play an essential role in our daily lives.
By safely and effectively removing soils, germs and other contaminants, they help us to stay healthy, care for our homes and possessions, and make our surroundings more pleasant. Soaps are water-soluble sodium or potassium salts of fatty acids.They are an example of surfactants, which reduce the surface tension of water so it can spread and wet surfaces. Soaps are made from fats and oils from animal or plant sources. The main reaction in soap manufacture is called saponification.
This process is where fats and oils are reacted with sodium hydroxide or potassium hydroxide. This forms glycerol and the sodium or potassium salt of a fatty acid, which is a soap. The effectiveness of soap is reduced when used in ‘hard water’. Hard water contains calcium and magnesium ions in solution.These salts react with soaps to form an insoluble precipitate known as soap film or soap scum, which do not rinse away easily and attaches to the sides of bathtubs and sinks. Synthetic detergents are effective cleaning products because they contain more than one surfactant and can perform well under a variety of conditions, including in hard water. Synthetic detergents were developed partly in response to various problems with soaps.
These were that soaps do not lather in hard water and soap anions protonate in acidic water to form insoluble fatty acids, again destroying the lathering property of the soap.Detergent today are made from petrochemicals and have a similar long hydrocarbon chain to soaps, but the ionic group at the hydrophilic head has been changed. Most detergents will lather in hard water, apart from sodium dodecyl sulfate. There are three main types of detergents: Anionic detergents Anionic detergents are the most widely used detergent and is where the surfactant has a negatively charged head. Anionic detergents are high sudsing and are used mainly in laundry and dishwashing detergents, e. g. Omo and Morning Fresh. The structure of an anionic detergent Cationic detergents:Cationic detergents have a positive charge and are used as fabric softeners.
Most fabrics accumulate negative charges on their surfaces. The positive charges on cationic detergents help to neutralise the charges and make a fabric feel softer. The structure of a cationic detergent Non-ionic detergents: Non-ionic detergents will not ionise in water and have no electrical charge. These detergents are resistant to water hardness and are low sudsing. They are commonly used in dishwashing detergents. The structure of a non-ionic detergent There are various environmental impacts and concerns of soaps and detergents.Soaps are made from natural organic products, thus they are biodegradable, meaning they are broken down in the environment into smaller substances such as water and carbon dioxide. Synthetic detergents were developed to overcome problems with soaps, yet many of the earliest were non-biodegradable or degraded very slowly.
They also included highly branched hydrocarbon tails. This caused many waterways in the 1960s and 70s to build up large amounts of foam. Industrial chemists eventually solved this problem by synthesizing biodegradable detergents with non-branching tails that could readily be broken down.The problem of frothing on rivers and lakes, which was a common sight until the mid-1960s, has largely disappeared.
The presence of phosphates is an environmental problem associated with the use of soaps and detergents. Phosphates were added to detergent powders in order to prevent calcium and magnesium ions from interfering in the washing process. These detergents have greater cleaning powers, however, the presence of phosphates bring great environmental concern. Phosphate residues can find their way into waterways and lead to algal blooms and eutrophication of waterways.These concerns are being solved by replacing phosphates with sodium zeolate. Zeolites help to remove calcium and magnesium ions from hard water and cannot cause the eutrophication problems associated with phosphates. Another environmental concern is biocidal properties of cationic detergents.
Cationic detergents have mild biocidal properties and are attracted to the membrane surfaces of bacteria where they disrupt the cellular process. This can alter the balance of bacterial decomposers that are essential for our environment.At high concentrations of cationic detergents bacteria will be killed, however at low concentrations, bacteria will be able to survive. This is only a small problem associated with the use of soaps and detergents as these types of detergents only represent a small percentage of detergents used in society. 3. MONITORING LEAD Lead is toxic to all living creatures, including animals. It is known as a cumulative poison, meaning it builds with each progressive trophic level and affects every system of the body. Lead is particularly dangerous with children as they are more likely to absorb the metal than adults.
Lead poisoning poses many problems and is linked with the retardation of intellectual development in children, brain damage, and neurological disorders. It is extremely important to monitor the levels of lead in the environment so to ensure that humans are not exposed to excessive concentrations. Lead was the most widely used heavy metal and was generally used in petrol and as a pigment in paints. These uses of lead are now banned in many nations, including Australia.
Areas that require monitoring of lead levels include the air, waterways, drinking water, soils and certain foods. 4.HEAVY METAL POLLUTION OF WATER Heavy metals are metals that have a relative density of 5. 0 or higher.
They include elements such as lead, mercury, cadmium and chromium. Heavy metals are toxic to humans and animals and when exposed to waterways pose great concerns. For example, when mercury is present in water, it can be absorbed by various creatures and can be concentrated in their flesh. This is typical of oysters. Animals that feed off contaminated creatures can then contaminate their own bodies. This is a problem as humans can eventually consume it and this will lead to severe health problems.Because of the toxicity and severe health effects of heavy metals, it is essential to be able to identify whether water has been contaminated or not.
Environmental chemists monitor heavy metal pollution in waterways. Rapid onsite measurements of heavy metals can be achieved by using ion sensitive electrodes (ICE), yet they may suffer from interference form other ions. The most effective process is atomic absorption spectroscopy (AAS), which is a highly versatile technique that can be applied to the analysis of many elements, notably metals.Another chemical method to obtain information about heavy metal levels in water is precipitation.
Precipitation is not as effective as it will only show the presence of heavy metal ions rather than discerning the specific heavy metals. In the future, the primary method that will be used to identify heavy metals will be inductively coupled plasma mass spectroscopy (ICP-MS) as it is much more sensitive than common methods currently used. 5. EUTROPHICATION OF WATERWAYS Algal bloom is a term that describes the excessive growth of cyanobacteria, algae and waterweeds.Algal bloom has become a major problem in NSW lakes and rivers. It results from water that is polluted with excessive amounts of nitrogen and phosphorus nutrients from sources such as farm water and laundry detergent.
Eutrophication is a term used to describe excessive algal growth in waterways and has several negative effects on the environment: * Sunlight is blocked by excessive plant growth at the water surface, meaning no light can penetrate deeper into the water to allow photosynthesis of other aquatic plants. Algal bloom interferes with diffusion of oxygen from the air into the water. * When the algae dies, dissolved oxygen levels in the water become depleted as decomposers break down their remains. This is extremely harmful to other organisms in the water. Once oxygen levels drop to near zero, anaerobic decomposers become active and foul odors are released into the water. Eutrophication occurs only under suitable environmental conditions and these include the presence of cyanobacteria, an abundance of mineral nutrients, warm weather, and little or no water movement.The harmful effects that eutrophication has on the earth makes it extremely important to monitor eutrophication in waterways. Following extensive research into the nitrogen and phosphorus requirements of various water plants including algae, chemists have developed guidelines for the protection of aquatic ecosystems from Eutrophication In order to avoid eutrophication, the levels of phosphorus must be lower than levels of nitrogen in waterways so that nutrient overload does not occur.
Overgrazing of livestock and overuse of fertilisers, particularly near waterways, should be stopped. Also, sewage disposal must be controlled and protection strips around lakes and rivers should be created. It is also important to test the water for phosphorus and nitrogen in order to keep levels low in waterways and protect from eutrophication. The Kjeldahl method is a procedure used to measure nitrogen in a water sample and involves converting all nitrogen in a sample to ammonia, which can then be measured by titrating with acid.Another way of determining the amount of nitrogen in a water sample is to use a colourimeter. The nitrate reacts with a substance to produce a pink-purple colour. Phosphorus content in water can also be measured colourimetrically.
This is done by oxidizing phosphorus to phosphate and reacting them with acid to form a blue complex. These methods allow chemists to detect low levels of these substances in water. 6.
CHLOROFLUOROCARBONS AND HALONS Haloalkanes are carbon compounds that consist of one or more halogen atoms in place of hydrogen atoms in a hydrocarbon.A chlorofluorocarbon (CFC) is a haloalkane that contains fluorine and chlorine atoms, but no hydrogen atoms. A halon is a haloalkane that contains bromine, chlorine or fluorine atoms, but no hydrogen atoms. CFCs were initially chosen because of their inert nature and the fact that they aren’t toxic. They were also developed to replace ammonia as refrigerants.
Along with being used as refrigerants, CFCs were extensively used as solvents in dry cleaning, propellants in spray cans and blowing agents for plastic products. Halons were developed for use as an extinguisher for electrical fires.Through these various uses, CFCs and Halons have been released into the atmosphere, resulting in negative effects to the environment. Dichlorodifluoroethylene, an example of a CFC The main problem associated with the use of CFCs is the destruction of the ozone layer, causing a decrease in the stratospheric ozone concentration. These decreases occur particularly at the two poles and were first detected in the 70s and 80s.
Because ozone can absorb medium and high ultraviolet radiation, the decrease in ozone concentration causes more radiation to reach the earth, resulting in various negative health effects.These include sunburn, skin cancers, eye cataracts, decreased immune response, plant damage, and polymer decomposition. The only way to alleviate these problems is to stop the release of CFCs into the atmosphere. Several international agreements have been established that aim to prevent and stop the use of CFCs. The Montreal Protocol was signed in 1987 by 27 nations and required the immediate freezing of 1986 levels of CFC production and aimed to reduce CFC production by 50% by the year 2000. In 1990, a further agreement was made in London and involved the elimination of the roduction and use of CFCs by 2000, eliminating the production and use of 1,1,1-trichloroethane (methyl chloroform) by 2005 and the elimination of the production and use of HCFCs by 2040. In 1992, there was yet another agreement made in Copenhagen.
This agreement involved eliminating the production and use of halons by the end of 1994, eliminating the production and use of CFCs and methyl chloroform by 1996 and the provision of financial aid to developing nations for the implementation of those measures.Australia has also been involved in these agreements and has been successful in adhering to terms and timetables. Research shows that these international agreements have been successful in solving the problem of ozone depletion. While there have been measures that prevent the production and use of CFCs in the environment, we cannot remove the CFCs already in the stratosphere at this stage of technological development. So some measures are needed to reduce the effects of the problems caused by CFCs, such as high levels of UV radiation.These measures include the use of new sunscreens, as advised by organisations like the Cancer Council, and the use of UV stabilizers in polymers that are exposed to sunlight to reduce breakdown by UV radiation. Ozone Depletion Since 1957, there have been measurements of the total amount of ozone in a column of atmosphere and in the 1970s it was discovered that CFCs were destroying the ozone layer in the stratosphere. Stratospheric ozone can be monitored in various ways through ground-based instruments, satellites, aircraft and balloons.
An example of an instrument used to monitor ozone levels is the Ultraviolet Spectrophotometer. These can be directed upwards through the atmosphere as to measure the intensity of wavelengths on either side of the range, providing a measure of the total ozone in the atmosphere per unit area of Earth surface at the location of the spectrophotometer. These can also be directed downwards through the atmosphere on helium balloons. Total Ozone Mapping Spectrophotometers (TOMS) are another type of instrument used to monitor ozone levels in the stratosphere.These are used onboard satellites to scan the atmosphere and measure ozone concentration.
TOMS have been on board several US satellites in recent years and can be used to produce ozone profiles and contour maps. TOMS have especially been important since the 1980s in producing maps of the ozone holes. Due to the decrease of the release of CFCs and halons, it has been seen that there has been a decrease in the rate of ozone depletion.
TOMS total column ozone measured over the period 1990-2005 Chemicals replacing CFCsHydrochlorofluorocarbon (HCFCs) are haloalkanes containing hydrogen, chlorine and fluorine atoms. These were the first substances used as replacements for CFCs, yet they still diffused into the stratosphere and caused significant ozone destruction. More successful chemicals known as Hydrofluorocarbons (HFCs) are widely used as a replacement for CFCs due to their chemical properties. They are non-flammable, of very low toxicity, recyclable, energy efficient and have no impact on the ozone layer.Both HFCs and HCFCs allowed the aims of the Montreal Protocol to be met without the disruption to everyday life and helped many countries meet their commitment to the Protocol early. 7.
REPLACEMENTS FOR NATURAL PRODUCTS As human population increases, the demand for natural resources increases as well, yet the supply of raw materials is limited. The overuse of these raw materials leads to depletion or even permanent loss of the resource in the future. Actions like recycling are important for the issue of shrinking world resources yet it cannot completely solve the problem.
The development and production of new synthetic materials to replace natural products is driven by many factors. These include meeting new demands, depletion of raw materials and increasing prices. Synthetic Vanillin Vanillin is a pleasant-smelling aromatic compound found naturally in vanilla beans. Its molecular formula is C8H8O3. Vanilla extract is used in a wide variety of foods as flavouring, as well as in cosmetics as a perfume. Vanilla was first used in sixteenth-century Mexico when its emperor flavoured his drinking chocolate with the pods of the vanilla bean.Due to this, Mexico became the leading producer of vanilla beans and vanilla extract for three centuries.
Currently, the demand for vanilla flavouring has long exceeded the supply of vanilla beans. As of 2010, the annual demand for vanillin was higher than 15000 tons, but about 2000 tons of natural vanillin was produced, the rest being produced by chemical synthesis. Synthetic vanillin is six times cheaper to produce than natural vanillin.
Synthetic vanillin molecules are identical, yet the synthetic vanillin lacks the entire body and flavour of natural vanillin obtained by curing vanilla beans.This product is used mainly with stronger flavours and scents such as chocolate and cinnamon, due to it being less intense than real vanillin obtained from vanilla pods. Another synthetic product, ethyl vanillin, is a compound that is 3 times stronger in flavour than real vanilla and is used as a substitute in foods and perfumes. Although the taste is not quite the same, it is much cheaper and keeps better in storage. CONCLUSION In every field of endeavor, Chemistry has played an integral role in both determining the advancement of life and the quality of the environment.
There have been various problems associated with its advancement in society, for example the depletion of the ozone layer due to the excessive use of CFCs, but recent measures seem to be counteracting this fairly effectively. The world of synthetic chemistry has flourished as greater demands are being placed upon it, as the decrease of natural resources is an ongoing concern. Agricultural practices such as the overuse of fertilisers has contributed to an escalation of algal blooms, and ensuing eutrophication of waterways.There have been various measures placed in order to counteract this issue, such as the placement of strips or buffer belts around rivers. As the world of science is utilizing alternative sources of power, such as nuclear fuel, the great importance of safeguards concerning their use has to be critically emphasized as the disaster in Chernobyl highlighted. The recent problems with the reactor at Fukushima demonstrate that ongoing safety measures are still insufficient to control such a powerful energy source.
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