Chemistry and SocietyUnit 46: Chemistry and the Environment

1. Define the terms pollution and pollutant.

Ans: Pollution is the introduction of waste matter or energy into the environment by humans. It causes damages or deterioration to living systems and/or the environment.

A pollutant refers to any substances or energy produced through human activities

which, at an unacceptable level, causes damages to the environment or is harmful to living systems.

2. What are the major air pollutants?

Ans: The major air pollutants include carbon monoxide, sulphur dioxide, nitrogen oxides, hydrocarbons, ozone and particulates.

3. What are their sources or formation with the help of equations? Ans: The major source of carbon monoxide is motor car exhaust. It is produced

through incomplete combustion of carbon-containing fuels, such as petrol, coal and wood. For example, octane may be burnt incompletely as follows:

C8H18 (g) + 9O2 (g) → 3CO2 (g) + 3CO (g) +2C(s) +9H2O (l)

Sulphur dioxide comes mainly from burning fossil fuels (e.g. fuel oil and coal) which contain sulphur. It is also produced during the operations in power stations and metal shelters in which sulphur-containing coal is used as the fuel, and also the manufacturing industries in which fuel oil is burnt.

S(s) + O2 (g) → SO2 (g)

Nitrogen oxides are produced whenever fuels are burnt at a very high temperature. It also comes from diesel-driven vehicles running in the territory. Diesel engines produce much less carbon monoxide but a lot more nitrogen oxides than petrol engines.

N2(g) + O2(g) → 2NO(g)2NO (g) + O2 (g) → 2NO2 (g)

Hydrocarbons are formed from the evaporation of organic materials such as petrol, diesel and solvents. They are also found in car exhaust as unburnt hydrocarbons.

Ozone is produced by the reaction of oxygen gas with free atoms of oxygen which are formed from the reactions between nitrogen oxides and hydrocarbons in sunlight.

O2 (g) + O O3 (g)Oxygen Radical

The particulates are produced during the operations in incinerators, factories, diesel vehicles, construction sites and coal or charcoal burners. They are solid or liquid particles and are so small that they remain suspend in air for a long period of time.

4. What are the common effects of these pollutants?

Ans: Carbon monoxide reduces the amount of oxygen delivered to body organs and tissues or even causes death.

Sulphur dioxide will impair the respiratory function and aggravate existing respiratory diseases (e.g. bronchitis and asthma) and cardiovascular diseases.

Nitrogen oxides will irritate the lungs and lower the resistance to respiratory infections, and causes the formation of photochemical smog and acid rain.

Hydrocarbons will cause photochemical smog. Some of them are carcinogenic.

Ozone will affect the respiratory system and increase susceptibility to respiratory infections, and damage plants.

The particulates will impair the lung function by hindering gas exchange and damaging lung tissues, and cause respiratory illnesses.

5. What are the factors that the harmful effects of pollutants depend on?

Ans: The harmful effects of pollutants depend on their concentrations and the duration of exposure to them.

6. What does ppm stand for?

Ans: ppm (parts per million) is the number of molecules of pollutants per million (10 ) molecules in air. It is thus a ratio with no unit. Based on the Avogadro’s law, ppm is also equal to the number of volumes of pollutants per million volumes of air.

7. Express 0.03 ppm SO2 as μg m ³.

Ans: In 1m³ of air, there is 0.03\10 m³ carbon monoxide. Using the ideal gas equation, PV=nRT = (Mass of SO2 / M) RT where M is the molar mass of SO2. Mass of SO2 = P V M RT = (101X10³Pa) (0.03/10 m³)(64 g mol ¹) ( 8.314J K ¹ mol ¹)(298 K) = 78.3 μg Therefore, the concentration of sulphur dioxide is 78.3μg m ³.

8. Decide whether the unpolluted rainwater is acidic or alkaline? Explain with the help of equations?

Ans: The unpolluted rainwater is slightly acidic, with a pH value of about 5.7. It is because as it falls, the rainwater reacts with carbon dioxide in the air to form carbonic acid.

CO2 (g) + H2O (g) → H2CO3 (aq)

9. What are the two major air pollutants responsible for the formation of acid rain? Write down the relevant equations.

Ans: Acidic gaseous pollutants like sulphur dioxide and nitrogen dioxide are responsible for the formation of acid rain. Sulphur dioxide is mainly released from the burning of fossil fuels in power stations.

2SO2 (g) + O2 (g) → 2SO3 (g)SO3 (g) +H2O (l) → H2SO4 (aq)2NO (g) + O2 (g) → 2H2SO4 (aq)

4NO2 (g) + 2H2O (l) +O2 (g) → 4HNO3 (aq)

10. What are the effects of the acid rain on the environment?

Ans: Acid rain causes a lot of harmful effects on environment. In the water of pH lower than 4.5, calcium metabolism in freshwater fish will be affected, leading to poor health and stunted growth. As a result, the diversity and population of some freshwater species will be reduced. In soil of pH lower than 4.5, absorption of essential nutrients by plants will be affected, resulting in the death of plants.

Acid rain also corrodes metals and accelerates the rate of deterioration of buildings, rocks and statues.

11. What does it mean by photochemical smog?

Ans: The word “smog” comes from two words: smoke and fog. Photochemical smog is a mixture of pollutants including particulates, nitrogen oxides, ozone, aldehydes, peroxyacetyl nitrate (PAN) and unreacted hydrocarbons, etc. A brownish haze that irritates our eyes is an indicator of photochemical smog. Nitrogen dioxide is responsible for the brownish color of the haze.

12. How is the photochemical smog formed?

Ans: Reaction that lead to the formation of photochemical smog are initiated by sunlight and involve hydrocarbons and nitrogen oxides emitted from automobiles. The combination of sunlight, particulate matters and abundant pollutants present in modern cities provide favourable conditions for smog formation.

Nitrogen dioxide from automobile exhaust first absorbs sunlight and breaks down into nitrogen monoxide and free oxygen atom which is very reactive.

UV lightNO2 (g) → NO (g) + O (g)

The oxygen atom then reacts with other components of automobile exhaust (e.g.unburnt hydrocarbons) and those of the atmosphere (e.g. oxygen and water vapour) in a series of complex reactions to produce a variety of lachrymatory and toxic chemicals such as peroxyacetyl nitrate (PAN).

Very much simplified, some of the principal reactions involved in the formation of photochemical smog are illustrated below:

O (g) + O (g) → O3 (g)O (g) + hydrocarbon → aldehydes

O3 (g) + hydrocarbons → aldehydes

Hydrocarbons + O2 (g) + NO2 (g) → lachrymatory substances, including PAN

13. What are the effects of the photochemical smog?

Ans: Photochemical smog causes headaches, eye, nose and throat irritation, worsening of the lung function, coughing and wheezing. Ozone attacks the C=C linkage in rubber in a process known as ozonolysis. It can also cause rubbers and fabrics to deteriorate and car tyres to crack.

14. What is the formula of ozone?

Ans: Ozone is formed from atmosphere oxygen by absorption of ultra-violet radiation of the right energy (wavelength 250nm), which dissociates oxygen molecules into free oxygen atoms.

O2 (g) → 2O (g) The oxygen atoms produced react with other oxygen molecules to form ozone.

O (g) + O2 (g) → O3 (g) 15. What is the formation of the ozone in the lower part of atmosphere?

Ans: In the lower part of the atmosphere, (i.e. the troposphere), ozone can be formed in a number of ways: by the reaction between nitrogen oxides and hydrocarbons in sunlight; by electric sparks which occur in car engines and electrical appliances (e.g. photocopiers and electric motors ); and by lightning. It can also be formed by passing a steam of oxygen through an electric discharge. However, ozone is very reactive (oxidizing). So it does not stay in the atmosphere for a long time.

16. What is the formation of the ozone in the stratosphere? In the stratosphere, ozone is formed from atmospheric oxygen by absorption of ultraviolet radiation of the right energy (wavelength 250nm), which dissociates oxygen molecules into free oxygen atoms. The oxygen atoms produced react with other oxygen molecules to form ozone. O2(g) 2O(g) O(g) + O2(g) O3(g) 17. What happen to ozone if it absorbs UV radiation of wavelength 215 to 295nm? When ozone absorbs ultraviolet radiation of wavelength 215 to 295, it undergoes photodissociation and splits up again. O3(g) O2(g) + O(g)

18. What is the significance of the above reactions? The reactions are responsible for the vital screening effect of ozone and screen off the harmful ultraviolet radiation. As ozone is constantly created and destroyed in the stratosphere, its concentration remains constant.

19. What are the effects of ozone to human? Ozone filters out 99% of the dangerous ultraviolet radiation from the sun. When the ozone layer is depleted, increased penetration of solar ultraviolet radiation is likely to have high impact on human health with potential risks of eye diseases, skin cancer and infectious diseases.

20. What would happen if the ozone layer becomes thinner? If the ozone layer becomes thinner, it will affect the lives of living organisms on the Earth. There is an increase in the amount of ultraviolet light reaching the Earth’s surface as its function is to shield us from the ultraviolet radiation of the sun. This will lead to an increase in the incidence of skin cancer, genetic mutation, cataract, and a decrease in the yield of crops.

21. What substances would cause a decrease of ozone in the atmosphere? Ozone is highly reactive and easily broken down by man-made chlorine and bromine compounds. Chlorofluorocarbons (CFCs) which are compounds containing chlorine, fluorine and carbon and other ozone-depleting substances ODS would cause a decrease of ozone in the atmosphere. Strong UV light breaks apart the ODS molecules. CFCS, HCFCS, carbon tetrachloride, methyl chloroform release chlorine atoms, and halons and methyl bromide release bromine atoms. The chlorine and bromine atoms destroy the ozone.

22. Using one of the substances in Q.21, write down the relevant equations for depletion of the ozone in the atmosphere. One of the substances is CCl3F. After absorbing ultraviolet radiation, the equation is: CCl3F CCl2F (g) + Cl (g) Then, the free chlorine radicals (Cl ) steps readily react with ozone. Here are the equations: Cl (g) + O3(g) ClO (g) + O2(g) ClO (g) + O3 Cl (g) + 2O2(g)

23. Give some alternatives for CFCs compounds. CFCs such as CCl3F and CCl2F2 are used as aerosol propellants because they are

good solvents with low boiling points and are odourless, non-flammable, stable and non-toxic. For CCl2FCClF2, it can dissolve grease and it is used as solvents in cleaning electronic components and metals. A series of CFCs, Freon (CCl2F2), absorbs heat of vaporization on evaporation and cools the surroundings. So, it is widely used as refrigerants in refrigerators and air conditioning units. A volatile CFC such as CCl3F is incorporated into the plastics in order to make foam plastics. The heat evolved during the polymerization reaction vaporizes the CFC which forms tiny bubbles in the plastics.

24. What are the causes of water pollution? Water pollution is caused by livestock waste, oil spillages, residues of pesticides, detergents in sewage and industrial effluents.

25. What are the effects of water pollution? When there is an excessive amount of organic matter discharged into water, the existing micro-organisms will grow rapidly and oxygen is also depleted rapidly. Thus, anaerobic micro-organisms break down the organic matter, releasing noxious gases and leading to the death of aquatic organisms. For oil spillages, oil clogs the feathers of sea birds and prevent them from flying or swimming. It also interferes with the insulation of the feathers of birds and causes the death of them from cold or pneumonia. Oil will poison the birds by ingestion and prevent dissolution of oxygen, causing the death of aquatic organisms. Besides, oil deposited on beaches spoils recreational resorts.When the residues of pesticides entry into the water, they will accumulate along the food chain and have the potential for damaging internal organs. Also, the reproduction of the animals will be affected and even exerted harmful effects.Discharge of detergents in sewage causes eutrophication brought about by phosphates found in some detergents. It also causes foaming in rivers and lakes that leads to the death of aquatic organisms.Industrial effluents may contain heavy metals which are toxic. They will accumulate along the food chain and cause death of animals when a toxic level is reached.

26. What does DO stand for? DO stands for dissolved oxygen.

27. What is the indication of the DO value? DO value indicates the oxygen content in water. It is measured in mg of oxygen per dm of water or percentage saturation of dissolved oxygen.

28. What does BOD stand for?BOD stands for biochemical oxygen demand.

29. What does it mean by five-day BOD?BOD is determined in the laboratory by incubating a water sample for five days at 20 C and measuring the amount of oxygen consumed and it is known as five-day BOD.

30. What is the indication of the BOD value?BOD is an indicator of the extent of organic pollution. It indicates the relative oxygen requirements in treating effluents and polluted waters.

31) Putrescibles, paper, plastics, metals

32) Incineration and land filling

33) Incineration advantages:1)reducing the volume of the waste by about 85%2)killing the disease-causing organisms at high temperature3)have no risk of causing water pollutiondisadvantages:

1) potential danger of polluting the atmosphere with toxic chemicalsland filling advantages:1) land fill gas(methane) will give out and can be collected and used as an energy

source in some countriesdisadvantages:1) land fill gas(methane and lechate) which is harmful and highly polluting water

percolating through decaying waste in landfill

34) As plastics are chemically tailored for long life, they do not generally undergo decomposition in landfill sites. Plastic waste can last for a long time, thus delaying the reuse of the landfill sites. Incineration of plastic waste produces air pollutants such as HCL from polyvinyl chlorine and other chlorine-containing polymers. The HCL produced can cause acid-rain which damage the environment plastic waste in sea poses direct danger to fishes. Small fishes have been found dead with their digestive tracts clogged by fragments of plastic foam they had ingested sea animals have been suffocated to death by plastic bags. The use of certain chemicals such as plasticizers and chlorofluorocarbons in the manufacture of plastics leads to further ecological and environmental problems.

35)Landfill: methane gas can be collected and treated and used as energy sources. Leachate can be treated in sewage treatment plant.Plastic waste: as plastics are indispensable in modern life, the associated pollution problems have to be solved. To tackle the problem of waste disposal, degradable plastics are being developed and processes for recycling plastic wastes are now underway.

36) Environmental Protection Department.

37) 1) use of unleaded petrol 2)installation of catalytic converters in car exhaust system 3)limitation of sulphur content in fuels

4) desulphurization of flue gas 5) installation of electrostatic precipitators in power plants 6) installation of low nitrogen oxide burners in power plants

38) 1) treatment sewage-screening and sedimentation-digestion of pollutants by micro-organisms.

2) treatment of chemical waste from industry and laboratories.

39) chemical waste treatment center.

40) provide proper waste treatment services for local waste producers. 3 major waste treatment in the center. -oil/water separation system-to recovers waste oil form oil mixture -physical-chemical treatment system-treats water-based chemical waste such as acids,

alkalis and waste water containing heavy metal salts. -high temperature chemical waste incinerator to destroys hazardous organic waste such as

pesticides and polychlorinated biphenyls and cyanide waste. 41) ‘Reduce, Reuse and Recycle’ – to help in minimizing waste, reducing the demand for

scarce landfill space and saving resources. Discarded items such as newspaper, office paper, aluminum cans, glass containers and certain plastic items can be collected for reusing or recycling. For example in Hong Kong, most of the locally filled glass beverage bottles are recovered for reuse through a deposit system. In fact, most of the wastes recovered and exported for subsequent recycling overseas

unit 47: Chemistry and Food

1. Broken down into its constituent amino acids.

2. Monosaccharides (C6H12O6), disaccharides(C12H12O11), polysaccharides((C6H10O5)n)

3. What is the general formula for carbohydrates?The general formula for carbohydrates is CxH2yOy.

4. What does it mean by the acyclic and cyclic forms of glucose molecule? What does it mean by glycosidic linkage in carbohydrates?Glucose can exist in acyclic form and cyclic forms.

Glucose does not exist as the open-chain structure in the solid state. It exists as in one of the two cyclic forms. When the cyclic forms of glucose are dissolved in water, either of α-glucose or β-glucose will be converted to the other form, until an equilibrium mixture is formed, together with a minute amount of the acyclic form.

The bond formed between two monosaccharides is called a glycosidic linkage. It is formed from the condensation reaction between two –OH groups of two monosaccharides with the elimination of a water molecule.

5. Illustrate by an example.Two glucose is bonded by glycosidic linkage to form maltose.

One of the cyclic formsAcyclic form

6. What is/are the factor(s) affect the hydrolysis of sucrose and starch?The dilute mineral acids, enzymes, , dilute sulphuric(VI) acid affect the hydrolysis of sucrose and starch.

7. What are the basic structural units for the fat?The basic structural units for the fat are

:

8. Write down a general equation for the formation of soap by using natural fat.

9. Define the term “iodine value”?The iodine value of a fat and an oil is defined as the number of grams of iodine that reacts with 100 grams of the fat or oil.

10. What is the indication of the iodine value?The higher the iodine value, the greater is the degree of unsaturation in the fat or oil.

11. What does it by hardening of vegetable oil?The C=C double bonds present in unsaturated oils can be converted to single bonds by the addition of hydrogen in the presence of a catalyst. The process is known as hydrogenation.

12. What does it mean by rancidity? How many types are there? Describe each of them with the help of equations.Fats or oils are liable to spoilage which results in the production of an “off” odour and a flavour described as rancidity. There are hydrolytic and oxidative rancidity

Hydrogen rancidity is due to the presence of moisture in fats and oils, which causes the hydrolysis of the glyceride molecules to propane-1,2,3-triol and free carboxylic acids. This may occur in the frying of potato chips in oil at a high temperature. The water released from the chips causes the hydrolysis of oil.

Oxidative rancidity is the most common and important type of rancidity. Oxidative spoilage occurs when fats or oils are exposed to air and undergo oxidation. It results in the production of flavours such as “tallowy”.Fats and oils having a high degree of unsaturation are more susceptible to oxidation. The oxidation is a free radical mechanism and is accelerated by trace metals, light and free radical initiators. The reaction for a segment of an unsaturated carboxylic acid chain may be simplified as follow:

The hydroperoxides produced are flavourless and odourless, but they can easily decompose to form highly reactive hydroperoxide free radicals. These radicals set up a chain reaction and produce volatile, flavoured compounds of aldehydes, ketones and carboxylic acids, which are responsible for their rancid flavour. The process is called autoxidation.

13. What are the causes of food spoilage?The causes of food spoilage are due to microbial activities and chemical changes.

14. Give some principle of food preservation.The principles of food preservation are removal of moisture, altering temperature, changing pH, use of osmotic process, use of chemical additives.

15. Give some common techniques of food preservation. Briefly describe the principle behind each of them.The food can be preserved by heat treatment, this can kill the micro-organisms in food. The food can also be preserved by refrigeration, this can slow down the microbial and enzymatic activities. The food can be treated with salt or concentrated salt solutions, the can remove the water for enzymatic action and microbial growth by osmosis.

16. What are the functions of BHA/ BHT?The functions of BHA/BHT are to inactivate or kill micro-organisms, retard chemical spoilage.

17. The possible menace of using too much food additives are:1) Allergies: Certain people may develop rashes and stomach upsets, etc, with

particular food additives.2) Hyperactivity: Some additives, particularly food colorings, are believed to

cause hyperactivity in children who are over-active and do not sleep much.

3) Long term illness: Some additives like oil of calamus, dulcin ,butter yellow and safrole have been banned because they cause long term illness, such as cancer.

18. Monosodium glutamate (MSG) does not add any taste to food but is a flavourenhancer. That means, it does not change the original flavour of the food but make it more noticeable and tasty. MSG is commonly used in chicken broth, soup bases for instant noodles, etc.

19. In some people MSG has been associated with the so-called ‘Chinese restaurant syndrome’, an unpleasant reaction. Careful studies have shown that some people are sensitive to MSG. Reactions include headache, nausea, weakness, and burning sensation in the back of neck and forearms. Some people complain of wheezing, changes in heart rate, and difficulty breathing. Some people claim to be sensitive to very small amounts of MSG, but no good studies have been done to determine just how little MSG can cause a reaction in the most-sensitive people. These side-effects are more prominent in some individuals and are dose-related.

20. In the meat, nitrates (V) are reduced to nitrates(III) It is actually the nitrates(III) which are responsible for developing the cured aroma and fresh pink colour in meats, and for inhibiting bacterial growth. Nitrates(III) are particularly effective in preventing botulism.

21. Excessive ingestion of nitrates(III) causes decreased levels of haemoglobin in the blood. Long term ingestion may lead to malnutrition, growth retardation, impairment of reproductive capacity and reduced lifespan.The potential carcinogenic nature of nitrates(III) include:a. High dosage of saccharin causes cancer.

b. Exposure to unusually high dosages of nitrates(III) shows increased incidence of stomach cancer.In the stomach, nitrates(III) are first converted to nitric(III) acids: NaNO2 + HCl —> H NO2 + NaClNitric(III) acid can react with secondary amines to give nitrosaminesHNO2 + R2NH R2N-N=O + H2O

Nitrosamines are carcinogenic.

22. Sodium dioxide gas and its salts are used to preserve fruit juices by preventing browning.

23. Sulphur dioxide is poisonous. Sulphur dioxide and its salts attack the respiratory system and individuals who suffer from chronic respiratory diseases such asbronchitis or asthma are much more susceptible to attack. It has caused at least twelve known deaths and probably many more.

24. Saccharin (Sweet 'N Low) is 350 times sweeter than sugar and is used in dietetic foods or as a tabletop sugar substitute.

25. Many studies on animals have shown that saccharin can cause cancer of the urinary bladder. In other rodent studies, saccharin has caused cancer of the uterus, ovaries, skin, blood vessels, and other organs. Other studies have shown that saccharin increases the potency of other cancer-causing chemicals. And the best epidemiology study (done by the National Cancer Institute) found that the use of artificial sweeteners (saccharin and cyclamate) was associated with a higher incidence of bladder cancer. The industry acknowledges that saccharin causes bladder cancer in male rats, but argues that those tumors are caused by a mechanism that would not occur in humans. Many public health experts respond by stating that, even if that still-unproved mechanism were correct in male rats, saccharin could cause cancer by additional mechanisms and that, in some studies, saccharin has caused bladder cancer in mice and in female rats and other cancers in both rats and mice.

26. All packaged foods and drinks in the European Union (EU), which includes

Britain, France and Germany (countries in the European Economic Community), are required to display a full list of food additives. A permitted food additive is assigned an E number. The ‘E’ means the additive is on the allowed list of additives which are generally recognized as safe according to European standards. Untested additives are not allowed and do not have an E number. The first digit tells us what class of additive it is .

27. Yes. Food additives are used extensively to prevent food spoilage. Food additives are used to maintain the safety of foods by slowing the growth of harmful bacteria that might otherwise lead to food poisoning. In the US there are 2000 food additives being used, generating approximately $4 billion in 1992. The beverage industry was the largest one Although no local figures are available, the personal yearly consumption of sugar and salt in HK are expected to account for a very high percentage by weight of all food preservatives used in HK.

28. Everybody takes in food additives everyday. It is very easy for our health to be threatened by food additives. Some scientists have linked additives - particularly tartrazine or E102 - to hyperactivity in children, allergies, asthma, migraines and even cancer. Sarah Schenker, a nutrition scientist for the BNF, said: "Some additives, especially some of the colourants, have been linked with hyperactivity in children, but the evidence is very ancedotal.” Not only the children, but also the adults, are the potential patients of cancers, owing to their frequent intake of food additives, e.g. MSG.

29. Ways to deal with the side effects of food additives:

1) If people noticed a side effect of an food additive they should simply cut the offending item out of their diet.

2) To protect the public's health, manufacturers and restaurateurs should use less or no MSG and the amounts of MSG should be listed on labels of foods that contain significant amounts. People who believe they are sensitive to MSG should be aware that other ingredients.

3) The way to handle food allergy is, if you break out in a rash or feel unwell after eating a particular food, find out what it contains and avoid anything with that food in future.

30. The government has done something to tackle these problems. In many countries, the use of food additives is governed by legislation. In Hong Kong, the Department of Health is empowered under the Public Health and Municipal Services Ordinance to control the uses of food additives to:

legislate permissible additives and the maximum limits of additives in particular foods,

require supply of information as to the composition of substances used in the preparation of food,

check on food labelling,

inspect food processing industries,

obtain samples for chemical analyses on foods and food additives,

seize and destroy food

prosecute for false labelling, advertisement or using additives beyond the permissible limits.

31. No. It is difficult for us to stop using food additives completely. Without food additives, biological contamination leads to such diseases as food poisoning and botulism and suboptimal intakes of key nutrients due to ignorance or indifference. Before the invention of food additives, manufacturers freely used pigments containing lead, copper and arsenic to color candy, Chinese duck egg and other foods. Food additives help us avoid the food hazards which were common in the middle of this century. Some food additives indeed are beneficial to us.

32. As mentioned above, some food additives are our needs, such as the antioxidants and unharmful colorings. However, according to The Center for Science in the Public Interest (CSPI), a US organisation that campaigns for food safety, many additives should be avoided for health grounds, especially for the sugar substitute Aspartame is sold commercially as Equal and Nutrasweet. People have reported dizziness, headaches, epileptic-like seizures, and menstrual problems after consuming aspartame. It should be banned by legislation as there is some evidence to suggest toxic levels of this substance in the blood can result in mental retardation. For other additives highlighted by the CSPI include: Caffeine, MSG, Saccharin, their dose used for cooking in restaurants should be under strict supervision.