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QUESTION 1

i) What is meant by BOD? (Biological Oxygen demand)?

Biological Oxygen Demand (BOD) is a measure of the oxygen used by microorganisms

to decompose this waste. If there is a large quantity of organic waste in the watersupply, there will also be a lot of bacteria present working to decompose this waste.

ii) Explain the causes of high BOD in natural environment.

BOD - biological Oxygen Demand is a measure of how fast biological organisms use upoxygen in a body of water. In natural environment, you have more living organisms inwater and they use up Oxygen leaving the water containing less oxygen. So, BOD ishigher.

QUESTION 2

ExplainFIVE functions of wetlands

Wetland Functions

1. Act like giant sponges to soak up water, reduce floods, and recharge groundwater.2. Provide resting place for migrating birds.3. Filter out pollutants, trap sediments, and improve water quality4. Provide water, food, protective cover and breeding areas for wildlife.5. Reduce soil erosion by slowing runoff from storms and spring runoff.

6. Provide nursery areas and protection for fish.7. Supply shade, water, and forage for livestock.8. Act as carbon sinks, helping to keep atmospheric carbon in balance (reduce

global warming).9. Supply agricultural products: cranberries, peat, blueberries10. Provide recreational, educational, and scientific opportunities.

QUESTION 3

List FIVE sources of indoor air pollution.

1. Carbon Monoxide: An invisible, odorless, and tasteless gas produced by theincomplete burning of carbon based fuels like gas and oil in devices likefurnaces, gas ranges, and non-electric space and hot water heaters.

2. Combustion by-products (CBPs): Gases and particles created by cigarettesmoking, fireplaces, woodstoves, furnaces, gas ranges, and non-electric spaceand hot water heaters.

3. Dust: Believe it or not, the average 6-room home accumulates roughly 40 poundsof dust each year, and here's not much we can do about it because dust- is being

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made around us all the time as the materials we se in our daily lives breakdownand shed microscopic particles. Household dust can contain tiny pieces ofextiles, wood, and food; mold spores; pollens; insect fragments; furs and hairs;and particles of smoke, paint, nylon, rubber, fiberglass, plastic, and paper.

4. Formaldehyde: A chemical used in everything from carpet and pressed wood

products like plywood to bed linens. Formaldehyde is a volatile organiccompound (VOC) but it's so common that some experts believe it to be the singlemost important indoor air pollutant. For this reason, it warrants a separatemention among the many hundreds of VOCs that can exist in indoor air.Formaldehyde is colorless gas with a sharp odor, although at the concentrationstypically found in indoor air, it is undetectable by the nose.

5. Composite or pressed-wood products are a common source of indoorformaldehyde. Wood resins and glues containing it are found in particleboard,plywood, paneling, furniture, wallboard and ceiling panels. Other sources includecarpets, decorative wallpapers, and fabrics in which formaldehyde is used as afinish to create permanent press, flame-resistant, water-repellant, and shrink-

proof materials. Formaldehyde can also come from gas stoves, glues, roomdeodorizers, cosmetics, personal care products, paper grocery bags, waxedpaper, paper tissues and towels, and even feminine protection products.

6. Nitric Oxide and Nitrogen Dioxide (Nitrogen Oxides): Colorless, odorless andtasteless gases produced by gas ranges. Ozone: A gas created by thebreakdown of volatile compounds found in solvents; reactions between sunlightand chemicals that are produced by burning fossil fuels; and reactions betweenchemicals found in materials like paint and hair spray.

7. Most ozone in the home comes from outside and results predominantly fromautomobile exhaust which is why this pollutant is more problematic in urban andsuburban homes than rural homes. Ozone can also come from copy machines,

laser printers, and ultraviolet lights.8. Particulates: Tiny particles of soot and other materials. The biggest sources ofindoor particulates are windblown dust, house dust, and tobacco smoke.Secondary sources include wood stoves and appliances like furnaces and non-electric heaters.

9. Pesticides: The mere act of applying these toxic materials spreads them aroundthe house and introduces them to indoor air. Residues that remain continue topollute the home and its occupants.

10.Radon: A natural radioactive gas that seeps from the rocks and soil surroundingcertain homes. Radon is odorless, colorless, and tasteless and largely a problemonly in basements in regions where soils have a large radon content.

11.Tobacco smoke: A mixture of over 4,700 different chemical compounds and the,single most preventable indoor air pollutant on this list.

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QUESTION 4

i) Explain why the biomass of primary consumers is less than the biomass ofprimary producers.

A pyramid of biomass is a representation of the amount of energy contained in biomass,at different trophic levels for a given point in time. The amount of energy available toone trophic level is limited by the amount stored by successively less total energy asyou move up trophic levels. In general, we would expect that higher trophic levels wouldhave less total biomass than those below, because less energy is available to them.

ii) Explain how harmful insecticides can be found in organisms at the higher trophiclevels.

A lot of the total energy and organic matter of an ecosystem is tied up in dead bodies.

Dead bodies contain energy (in the form of potential energy found in the chemicalbonds). They also contain organic (molecules containing carbon) and inorganic matter(e.g. iron, vitamins). Detrivores (scavengers) such as corpse beetles, jackals andvultures, and saprophytes such as bacteria and fungi break down this dead organicmatter. As a result, decomposers recycle a small part of the energy, but theysignificantly recycle the organic matter such as carbon, nitrogen and oxygen containedin these dead bodies.

All decomposers such as bacteria and fungi use this food in cellular respiration just asother consumers do. Therefore, they too release carbon dioxide and water back into theecosystem, making them available to other consumers.

QUESTION 5

i) Reason studying species that are threatened with extinction?

That threatened specie is filling an ecological niche one that might have a domino effectthis is only part of why endangered species are studied.

ii) Explain how geology, embryology and molecular biology supported the evolution?

The first of all everything started out with geology, because first the earth formed hensegeology. next molecules started to form proto bacteria that only multiplied by spliting,

AKA molecular biology. and finaly the bacteria evolved into creatures that finaly usedembryos to create a new living creature hense the evolution theory by Charles Darwin.

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PART BINSTRUCTION: Answer ALL questions. QUESTION 1

Question 1

Sanitary landfill is a form of waste treatment by burying waste materials.

i. What are the physical factors to be considered before building a sanitary landfill?

Basic requirements

As a minimum, four basic conditions should be met by any site design and operationbefore it can be regarded as a sanitary landfill:

Full or partial hydrogeological isolation: if a site cannot be located on land whichnaturally contains leachate security, additional lining materials should be brought to thesite to reduce leakage from the base of the site (leachate) and help reduce

contamination of groundwater and surrounding soil. If a liner - soil or synthetic - isprovided without a system of leachate collection, all leachate will eventually reach thesurrounding environment. Leachate collection and treatment must be stressed as abasic requirement. Formal engineering preparations: designs should be developed from local geologicaland hydrogeological investigations. A waste disposal plan and a final restoration planshould also be developed. Permanent control: trained staff should be based at the landfill to supervise sitepreparation and construction, the depositing of waste and the regular operation andmaintenance. Planned waste emplacement and covering: waste should be spread in layers and

compacted. A small working area which is covered daily helps make the waste lessaccessible to pests and vermin.

ii. Explain how pollutants can enter the environment from sanitary landfills.

Sanitary landfills often contain both domestic garbage and industrial wastes. Thewastes break down anaerobically within the landfill. After a period of time,the remainderof the wastes consists of refractory organic molecules, similar to those found in soils.

The leachate flows from sanitary landfill are controlled by the percolation rate (t.ethe precipication-runoff-evapotranspiration change in water storage).This could very considerably, often being between 15 to 50 percent of precipitation. Thepollution lead from a landfill also depend on the leachate quality, e.g, the concentrationsof present pollutants. The leachate flow, however, is often the most important factorcontrolling the pollution lead (e.g the mass flow). The primary concentrations ofpollutants are mainly controlled by physico-chemical and biochemical process, such assolubilization, sortion, ion-exchange or biological degradation. Physico-chemicalprocesses act as sinks for pollutants, resulting in a substantial decrease in pollutant

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mobility. The apparent effect of this phenomenon is lower concentrations of pollutants inthe leachate.

Leachate quality in sanitary landfill is to a very high degree, dependent onbiological degradation. It obviously will control the biochemical oxygen demand (BOD)and chemical oxygen demand (COD) of the leachate as well as metal and sulphate

concentrations. Any landfill containing biodegradable material will undergo separatedegradation phases., although the necessary time might differ substantially from onecase to another. When the landfill passes through the se phase, the leachate qualitychanges from a high pollution level to a rather low pollution level.

iii. Explain why source reduction is preferred than recycling and reusing.

Saves Natural Resources - By making products from recycled materials instead of virginmaterials, we conserve land and reduce the need to drill for oil and dig for minerals.Saves Energy - It usually takes less energy to make recycled products; recycled

aluminum, for example, takes 95% less energy than new aluminum from bauxite ore.Saves Clean Air and Water - In most cases, making products from recycled materialscreates less air pollution and water pollution than making products from virgin materials.Saves Landfill Space - When the materials that you recycle go into new products,they don't go into landfills or incinerators, so landfill space is conserved.

Saves Money and Creates Jobs - The recycling process creates far more jobs thanlandfills or incinerators, and recycling can frequently be the least expensive wastemanagement method for cities and towns.

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References

Dr. Ho Wei Song & Wong Sin Yeng. (2007) SBBI 4303 Environmental,

Biology. Oum.

http://pkukmweb.ukm.my

http://www.doe.gov.my

http://www.fkkksa.utm.my

http://www.sabah.gov.my

Mah Chee Wai & Dr. Tina Lim Awee Kim (2005). Ulangkaji Total SPM Biologi. Petaling Jaya. Sasbadi

Sdn. Bhd.

Noorlaili Ismail. (1998). Nota Komprehensif SPM Biologi. Petaling Jaya. PrestonCorporation Sdn. Bhd.

http://www.fkkksa.utm.my/http://www.fkkksa.utm.my/http://www.sabah.gov.my/http://www.sabah.gov.my/http://www.fkkksa.utm.my/