CBSE Class 6 Science Garbage In Garbage Out Exam Notes

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Garbage In, Garbage Out

Vermicomposting uses earthworms to turn organic wastages into very high quality compost. This is probably the best way of composting kitchen wastes.
Vermicompost consists mostly of worm casts (poop) plus some decayed organic matter. In ideal conditions worms can eat at least their own weight of organic matter in a day.

Two breeds of earthworm are used in vermicomposting. Eisenia foetida or Lumbricus rubellas. Many garden centres now supply them, and in most countries they can be bought by mail order from worm farms.

Paper recycling is the process of recovering waste paper and remaking it into new paper products. There are 3 categories of paper that can be used as feedstocks for making recycled paper mill broke, pre-consumer waste, and post consumer waste.

Paper suitable for recycling is called “scrap paper”, often used to produce moulded pulp packaging. The industrial process removing printing ink from paper fibres of recycled paper to make deinked pulp is called deinking, an invention of the German Jurist Justus Claproth.

1960 the first paper will to use recycled linen was established by the Rittenhouse family. Plastic is one of the few new chemical materials which pose environmental problem. Polyethylene, polyvinyl chloride, polystyrene is largely used in the manufacture of plastics. Synthetic polymers are easily molded made into complex shapes, have high

class_6_science_useful_023

chemical resistance, and are more or less elastic. Some can be formed into fibres or thin transparent films. These properties have made them popular for making many durable or disposable goods and for packaging materials. These materials have molecular weight ranging from several thousands to 1,50,000. Excessive molecular and their persistence in soil environment for a long time.

Packaging represents the largest single sector of plastic use in the world today. Benefits of plastic Boon. The considerable growth in plastic use is due to the beneficial properties of plastics. These include:
a) Extreme versatility and ability to be tailored to meet very specific technical needs.
b) Lighter weight than competing materials, reducing fuel consumption during transportation.
c) Extreme durability.
d) Resistance to chemicals, water and impact.
e) good safety and hygiene properties for food packaging.
f) Excellent thermal and electrical insulation properties.
g) Relatively inexpensive to produce.

Plastic makes up around 7% of the average household dustbin.
* Plastic as a Curse
* Misuse of any technology can lead to curse. Plastic was though to be a boon but it turned out to be a curse. Plastic can be very harmful as it produces harmful gases when it is burned. As it is non-biodegradable, it is harmful to the soil and takes hundred of years to degrade or decompose. With more and more plastic products, particularly plastic packaging, being disposed of soon after their purchase, the landfill space required by plastics waste is a growing concern.
* Plastic waste, such as plastic bags, often becomes litter. For example, nearly 57% of litter found on beaches in 2003 was plastic. The waste problem is a major curse, mainly because they degrade slowly. They are difficult to recycle because of the great variety of plastics which are hardly distinguishable.
* Many plastics posion the environment when degrading, PVC for example contains chlorine; generally there is no problem during use, but chlorine returns into the environment when the waste is processed. Also, the manufacturing of plastics often creates large quantities of chemical pollutants. World

Environment Day (WED) is a day that stimulates awareness of the environment and enhances political attention and public action. It is on 5 June. It was the day that United Nationals Conference on the Human Environment began.
The first World Environment Day was on 1973.

Environment Day is hosted every year by a different city with a different theme and is commemorated with an international exposition in the week of 5th June.

Theme 2011
Forests Nature at your service cover one third of the earth’s land mass, performing vital functions and
services around the world which make our planet alive with possibilities.

Theme 2010
‘Many Species. One Planet. One Future’, was the theme of 2010.

Theme 2009

class_6_science_useful_024
World Environment Day log for 2009. Your planet Needs You - United to Combat Climate Change.

 

Theme 2008

CBSE Class 6 Science Garbage In Garbage Out Exam Notes_1

World Environment Day Logo for 2008.

Vermicomposting

uses earthworms to turn organic wastes into very high quality compost. This is probably the best way of composting kitchen wastes. Adding small amounts of wet scraps to a large compost pile in the garden day by day can disrupt the decomposition process so that the compost is every really done. But it works just fine with vermicompsting. 

CBSE Class 6 Science Garbage In Garbage Out Exam Notes_2

Many gardeners use vermicomposting systems for all their garden and kitchen wastes, many more use both types of composting, and thousands of households without gardens use neat and unobtrusive worm boxes indoors to compost their kitchen scraps (as well as newspapers and cardboard boxes), reducing their garbage by up to a third and providing their own organic soil for pot plants and container gardens on balconies and roofs to grow their own healthy food.

Friend Earthworm: Practical Application of a Lifetime Study of Habits of the Most Important Animal in the World” by George Sheffield Oliver, 1941 — one of the all time classics on the earthworm. Dr. Oliver was one of the first to hardness earthworms to the needs to the farmer and gardener, making highly fertile to possil for optimum crop growth, and producing a constant supply of cheap, high grade, live protein to feed poultry. He devised simple yet elegant and effective systems to bring cross and labour down and productivity up to help struggling farmers make ends meet. Oliver had an observant and critical eye and understood Nature’s round. His ideas on the nature of modern food and health (or the lack of it) are only now being confirmed, half a century later. 

Vermicompost and Plants

Vermicompost consists mostly of worm casts (poop) plus some decayed organic matter. In ideal conditions worms can eat at least their own weight of organic matter in a day. In fact it seems they don’t actually eat it — they consume it, sure enough, but they derive their nourishment from all the micro-organisms that they are really eating. And yet — mystery! — their casts contain eight times as many micro-organisms as their feed! And these are the micro-organisms that favour healthy plant growth. And the casts don’t contain any disease pathogens — pathogenic bacteria are realiably killed in the worms’ gut. This is one of the great benefits of vermicomposting.

Worm casts also contain five times more nitrogen, seven times more phosphorus, and 11 times more potassium than ordinary soil, the main minerals needed for plant growth, but the large numbers of beneficial soil micro- organisms in worm casts have at least as much to do with it. The casts are also rich in humic acids, which condition the soil, have a perfect pH balance, and contain plant growth factors similar to those found in seaweed. There’s nothing better to put in your garden!.

— “Worms seem to be the great promoters of vegetation, which would proceed but lamely without them, by boring, perforating, and loosening the soil, and rendering it previous to rains and the fibres of plant, by drawing straws and stalks of leaves and twigs into it, and, most of all, by throwing up such infinite numbers of lumps of earth called worm-casts, which, being their excrement, is a fine manure for grain or grass”. — The Rev. Gilbert White of Selborne, 1777.

— “All the fertile areas of this planet have at least once passed through the bodies of earthworms”. — Charles Darwin, “The Formation of Vegetable Mould through the Action of Worms with Observations on their Habits”, John Murray, Londong, 1881.

The Worms 

These are not the usual big burrowing earthworms that live in garden soil. Called red worms, tiger worms, branding, angle worms, manure worms, or red wrigglers, they occupy a different ecological niche, living near the surface where there are high concentrations of organic matter, such as on pastures or in leaf mould, or under compost piles.

Two breeds are used in vermicomposting: Eisenia foetida or Lumbricus rubellas. Many garde centres now supply them, and in most countries they can be bought by mail order from worm farms. Some sellers advertise special high-performance breeds or specially developed hybrids, but don’t believe them — they’ll be one of these two breeds. There’s no such thing as hybrid worm.

We II need 1,000 worms (1 1b) to start a worm box, may be twice that if we want to process your garden wastes too — they breed very fast in the right conditions, but starting with more will give the system a good start.

Breeding

Worm populations double each month. In ideal conditions they can reproduce much faster than that: 1 lb of worms can increase to 1,000 lbs (one million worms) in a year, but in working conditions 1 lb will produce a surplus of 35 lbs in a year, because hatchlings and capsules (cocoons or eggs) are usually lost when the vermicompost is harvested.

Mature red worms make two or three capsules a week, each producing two or three hatchings after about three weeks. The hatchlings are tiny white threads about half an inch long, but they grow fast, reaching sexual maturity in four to six weeks and making their own capsules. Three months later they’re grandparents!.

This rapid breeding rate means the worm population easily adjusts to conditions in the worm box according to the feed supply and the proportion of worm casts to feed and bedding — their casts are slightly toxic to them, and as the box gets “full” they’ll either leave, if there’s anywhere for them to go, or they’ll die off.

Worm Boxes

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This section mainly applies to using worms to compost kitchen wastes. For garden wastes, the same basic principles apply, with a few cautions: see below, Garden wastes.

Dimensions

The size of the unit should be geared to your household’s production of kitchen scraps.

One or two people usually produce about 4 lb of food waste a week: use a 2ft × 2ft box 8” deep. For three people make it 12” deep, for more, 2ft × 3ft × 12” deep — or two 2 person boxes might be better, because bigger boxes can be too heavy to move when they’re full.

Use pexteior-grade 1/2” plywood. Don’t use chemically treated wood. Treat the wood with a non-toxic wood preservative, or paint it with vegetable oil, or linseed oil. Use galvanized nails. Drill at least a dozen 1/2” holes in the bottom for accretion, and arrange it so that two opposite sides are half-an inch deeper so that the bottom stands off the ground. Stand the box in a tray, because it will probably leak a bit.

Once filled, cover the surface with black plastic sheeting (a garbage bag) slightly smaller than the surface area: this will keep the moisture in, and the worms will work right up to the surface. If this makes ti too wet, use a couple of newspapers instead. Make a lid for the box. Keep it anywhere convenient.

Any inert, non-toxic, fluffy material that holds moisture and allows air to circulate will do. Don’t use anything that will decompose to rapidly when you moisten it and get hot, like manure that’ not aged enough or hay, especially alfalfa hay. Mixed bedding is better, but no need to be too complicated: 2/3 corrugated cardboard and 1/3 shagnum peat moss or coco peat moss is a good mixture, or sphagnum peat moss, shredded leaves and sawdust; or just cardboard and/or just cardboard and/or newspaper.

♦Cardboard cartons (corrugated); cut them up into strips an inch wide and a few inches long. Don’t use the shredded cardboard sold for insulation because isn’t treated with toxic chemicals. 

♦Newspaper: tear it into 1” strips — it’ easy to tear with the grain. Black ink is non-toxic, avoid glossy paper. 

♦Shredded computer paper 

♦Autumn leaves: spread them thickly in the drive way and drive over them with the car a few times to break them up, or shred them with a lawnmower. Or moisten them, sprinkle some lime, ground limestone or wood ash over them and bundle them up in a garbage bag, tie the top closed, and in a few months they’ll have broken down enough to be excellent worm bedding. Or just use them as is, though it’ll take a bit longer for the worms to break them down. 

♦Aged manure, or composted manure: cow, horse, rabbit.

♦Sphagnum peat moss: use Canadian peat moss, soak it in water for 24 hours, squeeze it out and sprinkle some lime on it.

♦Coco peat moss or coir (coconut fibres); comes in compressed bricks, soak in water and they swell up —no need to add lime.

♦Chopped-up straw or other dead plant material, spoiled hay, yard clippings, dried grass clippings: any plant material “aged” beyond the green stage.

♦Sawdust, wood shavings: from non-aromatic wood, avoid treated wood, about a quarter to a third of the bedding mixture.

Add a couple of handsful of soil or sand — it helps the worms grind up the food in their gizzards. Sprinkle a bit of lime, ground limestone or wood ash over the bedding (not too much!). Ground limestone is best.

Worm bedding and feed can be wetter than compost material: 75% compared with 65% maximum for compost. Dry bedding usually needs a bit less than three times its weight in water (a pint of water weighs a pound, a litre weighs a kilogram).

Once it’s all suitably shredded, mixed and moist, put it in the box and add the worms (about 1 lb — 1,000 worms). Leave it for two or three days to let the worms settle in before adding wastes.

Feeding 

No metal, foil, or plastic. Use vegetable and fruit scraps, coffee grounds (including paper filters), tea bags (remove the staple), eggshells (best dried and crushed first, then sprinkled over the surface), stale bread, house plant trimmings. Chop up big chunks. Some people advise against citrus, and also onion and garlic, others use them: try small quantities first. Not too much vegetable oil, be cautious at first with dairy products, meat and fish — small amounts chopped fine, well-dispersed and well-covered with bedding should be okay. Broken chicken bones are okay, bigger bones won’t break down, but shouldn’t cause problems either — they’ll be picked clean.

It’s best so collect food scraps in a small bucket with a lid and add them to the worm box every couple of days (or more often in hot weather — don’t left it go rotten). Bury them in the bedding in a corner of the box. Next time, bury the new scraps near the first scraps. You can have about nine burial sites in a 2 × 2 ft box: by the time you’ve used the ninth one, you can go back to the first site again, the worms will have cleared it.

You’ll be surprised how much feed you can put in that box — the worms and micro-organisms reduce it more than you’d think possible.

The box will need emptying every 3-6 months.

Best tool for burying feed: a three-pronged hand-cultivator (hand-fork).

Screening

The vermicompost might need screening, especially if you’re used rough stuff (sticks etc.) in the bedding that takes time to break down. A circular gardener’s sieve with a 3/16” mesh will work best. Try to get one with stainless steel mesh, it’ll do the job much quicker, the worm castings won’t stick to the mesh, and it won’t rust. This is also a good way of separating the worms from finished vermicompost, though capsules and hatchlings are lost.

Problems

Flies and smells — there shouldn’t be any, but sometiems it happens. Worm casts have a pleasant, earthy smell, like forest soil. If the worm bin starts to small, there’s too much feed in it, more than the worms can process — you’ve overloaded the system. Stop feeding the worms, add more dry bedding, a little sprinkled tim,e and stir the bin with the hand cultivator (hand-fork). Repeat until the smell vanishes. Fruit flies (actually vinegar flies) can get into the box, but they do not harm. Lots of them mean too much feed — cut down the feeding rate and cover the surface with a damp newspaper.

The bin can also have an influx of soldier fly maggots, up to an inch long (they are a favourite with fishermen). Vinegar fly larvae are much smaller. Actually the maggots benefit the composting process, but if you don’t like them, add more bedding and lime and stir as above, or put a chunk of bread soaked in milk on hte surface. In a couple of days ti will be infested with larvae; take it out and get rid of it (give it to a fisherman or a chicken).

Garden Wastes

Outdoor boxes can be bigger. The simplest way of all is a 12 inch deep trench in the soil about 2ft wide or more with 8” of bedding and/or compost to put the worms in. Red worms can’t survive long in ordinary garden soil so they won’t crawl away. Add garden wastes as they come, putting it in a different part of the trench each time, and cover with a sprinkling of soil and time. Bury kitchen wastes at the bottom, under the garden wastes. Fresh garden wastes might get hot, but the worms will have a place to escape to until it gets cool enough for them to handle. To keep moles away, line the trench with 1/2” chicken wire or wire mesh.

Or make a four-sides wooden box with four 18” by 36” boards (or nail narrower planks together), treat it with vegetable oil or linseed oil, and stand it on a layer of bricks on top of the soil. Put 6” or so of bedding in the bottom and put the worms in it. Add wastes to the corners in succession. Shake the soil off clumped roots. Chop up big, bits with the edge of a spade. Add more bedding as necessary. Bury kitchen scraps.

Paper Recycling

Paper recycling is the process of recovering waste paper and remaking it into new paper products. There are 3 categories of paper that can be used as feedstocks for making recycled paper: mill broke, pre-consumer waste, pre-consumer waste, and post-consumer waste. Mill broke is paper trimmings and other paper scrap from the manufacture of paper, and is recycled internally in a paper mill. Pre-consumer waste is material which left the paper mill but was discarded before it wasready for consumer use. Post-consumer waste is material discarded after consumer use, such as old corrugated containers (OCC), old magazines, old newspapers (ONP), office paper, old telephone directories, and residential mixed paper (RMP). Paper suitable for recycling  is called “scrap paper”, often used to produce molded pulp packaging. The industrial process of removing printing ink from paper fibers of recycled paper to make deinked pulp is called deinking, an invention of the German jurist Justus Claproth.

CBSE Class 6 Science Garbage In Garbage Out Exam Notes_4

 Paper Recycling by Region

European Union

Paper recovery in Europe has a long history and has grown into a mature organization. The European papermakers and converters work together to meet the requirements of the European Commission and national governments. Their aim is the reduction of the environmental impact of waste during manufacturing, converting / printing, collecting, sorting and recycling processes to ensure the optional and environmentally sound recycling of used paper and board products. In 2004 the paper recycling rate in Europe was 54.6% or 45.5 million short tons (41.3 Mt). The recycling rate in Europe reached 64.5% in 2007, which confirms that the industry is on the path to meeting its voluntary target of 6% by 2010. 

Japan

Municipal collections of paper for recycling are in place. However, according to the Yomiuri Shimbunin 2008, eight paper manufacturers in Japan have admitted to intentionally mislabelling recycled paper products, exaggerating the amount of recycled paper used.

United States of America 

Recycling has long been practiced in the United States. The history of paper recycling has several dates of importance:

♦1960: The first paper mill to recycled linen was established by the Rittenhouse family.

♦1896: the first major recycling center was started by the Benedetto family in New York City, where they collected rags, newspaper, and trash with a pushcart.

♦1993: The first year when more paper was recycled than was buried in landfills.

Today, over half of the material used to make paper is recovered waste. Paper products are the largest component of municipal solid waste, making up more than 40% of the composition of landfills. In 2006, a record 53.4% of the paper used in the US (or 53.5 million tons) was recovered for recycling. This is up from a 1990 recovery rate of 33.5%. The US paper industry has set a goal to recover 55 percent of all the paper used in the US by 2012. Paper packaging recovery, specific to paper products used by the packaging industry, was responsible for about 77% of packaging materials recycled with more than 24 million pounds recovered in 2005.

By 1998, some 9,000 curbside programs and 12,000 recyclable drop-off centers had sprouted up across the US for recycles collection. As of 1999, 480 materials recovery facilities had been established to process the collected materials. 

In 2008, the global financial crisis resulted in the price of old newspapers to drop in the US from $130 to $40 per short ton ($140/t to $45/t) in October.

Rationale for Recycling

Industrialized paper making has an effect on the environment both upstream (where raw materials are acquired and processed) and downstream (waste disposal impacts.

Today, 90% of paper pulp is made of wood. Paper production accounts for about 35% of felled trees, and represents 1.2% of the world’s total economic output. Recycling one ton of newsprint saves about 1 ton of wood while recycling 1 ton of printing or copier paper saves slightly more than 2 tons of wood. This is because kraft pulping requires twice as much wood since it removes lightning to produce higher quality fibres than mechanical pulping processes. Relating tons of paper recycled to the number of trees not cut is meaningless, since tree size varies tremendously and is the major factor in how much paper can be made from how many trees. Trees raised specifically for pulp production account for 16% of world pulp production, old growth forests 9% and second and third and more generation forests account for the balance. Most pulp mill operators practice reforestation to ensure a continuing supply of trees. The Programme for the Endorsement of Forest Certification (PEFC) and the Forest Stewardship Council (FSC) certify paper made from trees harvested according to guidelines meant to ensure good forestry practices. It has been estimated that recycling half the world’s paper would avoid the harvesting of 20 million acres (81,000 km2) of forestland.

Energy

Energy consumption is reduced by recycling. The Energy Information Administration claims a 40% reduction in energy when paper is recycled versus paper made with unrecycled pulp, while the Bureau of International Recycling (BIR) claims a 64% reduction. Some calculations show that recycling one ton of newspaper saves about 4,000 kWh (14 GJ) of electricity, although this may be too high (see comments below on unrecycled pulp). This is enough electricity to power a 3-bedroom European house for an entire year, or enough energy to heat and air-condition the average North American home for almost six months.

Recycling paper to make pulp actually consumes more fossil fuels than making new pulp via the kraft process; these mills generate all of their energy from burning waste wood (bark, roots) and by product lignin. Pulp mills producing new mechanical pulp use large amounts of energy; a very rough estimate of the electrical energy needed is 10 GJ per tonne of pulp (2500 kWh) per short ton).

Recycling mills purchase most of their energy from local power companies, and since recycling mills tend to be in urban areas, it is likely that the electricity is generated by burning fossil fuels.

Landfill Use

About 35% of municipal solid waste (before recycling) by weight is paper and paper products.

Plastics Boon or Curse

Plastic is one of the few new chemical materials which pose environmental problem. Polyethylene, polyvinyl chloride, polystyrene is largely used in the manufacture of plastics. Synthetic polymers are easily molded into complex shapes, have high chemical resistance, and are more or less elastic. Some can be formed into fibres or thin transparent films. These properties have made them popular in many durable or disposable goods and for packaging materials. These materials have molecular weight ranging from several thousands to 1,50,000. Excessive molecular size seems to be mainly responsible for the resistance of these chemicals to bio-degradation and their persistence in soil environment for a long time.

Packaging represents the largest single sector of plastics use in the world today.

Benefits of Plastics - Boon

The considerable growth in plastic use is due to the beneficial properties of plastics. These include:

 a) Extreme versatility and ability to be tailored to meet very specific technical need

 b) Lighter weight than competing materials, reducing fuel consumption during transportation.

 c) Extreme durability.

 d) Resistance to chemicals, water and impact.

 e) Good safety and hygiene properties for food packaging. f) Excellent thermal and electrical insulation propertie

g) Relatively inexpensive to produce.

 Plastic makes up around 7% of the average household dustbin.

Plastic as a Curse

Misuse of any technology can lead to curse. Plastic was thought to be a boon but it turned out to be a curse. Plastic can be very harmful as it produces harmful gases when it is burned. As it is non bio degradable, it is harmful to the soil and takes hundreds of years to degrade or decompose. With more and more plastic products, particularly plastic packaging, being disposed of soon after their purchase, the landfill space required by plastics waste is a growing concern.

Plastic waste, such as plastic bags, often becomes litter. For example, nearly 57% of litter found on beaches in 2003 was plastic.

The waste problem is a major curse, mainly because they degrade slowly. They are difficult to recycle because of the great variety of plastics which are hardly distinguishable.

Many plastics poison the environment when degrading. PVC for example contains chlorine; generally there is no problem during use, but the chlorine returns into the environment when the waste is processed. Also, the manufacturing of plastics often creates large quantities of chemical pollutants. 

Plasticizers like phthalates re suspected to cause upheaval in the hormone systems of animals and people, especially kinds.

Biodegradable and Non-Biodegradable Wastes 

Biodegradable Wastes

Is a type of waste, typically originating from plant or animal sources, which may be degraded by other living organisms. Waste that cannot be broken down by other living organisms are called non-biodegradable.

Biodegradable waste can be commonly found in municipal solid waste (sometimes called biodegradable municipal waste, or BMW) as green waste, food waste, paper waste and biodegradable plastics. Other biodegradable wastes include human waste, manure, sewage, slaughterhouse waste. In the absence of oxygen much of this waste will decay to methane by anaerobic digestion.

Climate Change Impacts

The main environmental threat from biodegradable waste is the production of methane in landfills. Methane is 21 times as potent a greenhouse gas as carbon dioxide and accounted for some 3% of total greenhouse gas emissions in the EU-15 in1995. The Landfill Directive 1999/31/EC obliges Member States to reduce the amount of biodegradable waste that they landfill to 35% of 1995 levels by 2016, which will significantly reduce the problem.

 Uses of Biodegradable Waste

Biodegradable waste can often be used for composting or must doubtless be a resource for heat, electricity and fuel in future as it is being achieved by the Swiss Kompogas treatment for 20 years now. This produces additional biogas and still delivers the compost fort the soil. It is a fully developed system and produced 27 million kWh of electricity and biogas in 2009. The oldest of the companies own lorries has achieved 1,000,000 kilometers drive with biogas from household waste in the last 15 years.

Non-Biodegradable Waste

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Non-Biodegradable Garbage

 Soil is getting polluted by pesticides, factory wastes, the reclamation of poisonous industrial and household wastes, and the careless abandonment of non-biodegradable garbage. Some of those wastes remain under the ground for 500 years, which pollutes the environment.

 Recently, the wastes that are not rotten easily, such as bottles, cans, plastics, vinyl, Styrofoam, and aluminium, are increasing so how to treat them is a worry. Incinerating the rotten wastes is a treatment way, but it can pollute the air or can generate the substances that have had influence on organisms. And it causes other environmental problems. Therefore, the quantity of wastes generated should be reduced as far as possible, and recyclable wastes should be recycled.

 Waste and Air Pollution

The United States Environmental Protection Agency (EPA) has found that recycling causes 35% less water pollution and 74% less air pollution than making virgin paper. Pulp mills can be sources of both air and water pollution, especially if they are producing bleached pulp. Modern mills produce considerably less pollution than those of a few decades ago. Recycling paper decreases the demand for virgin pulp and thus reduces the overall amount of air and water pollution associated with paper manufacture. Recycled pulp can be bleached with the same chemicals used to bleach virgin pulp, but hydrogen peroxide and sodium hydrosulfite are the most common bleaching agents. Recycled pulp, or paper made from it, is known as PCF (Process Chlorine Free) if no chlorine-containing compounds were used in the recycling process. However, recycling mills may have polluting by products, such as sludge. De-inking at Cross Pointe’s Miami, Ohio mill results in sludge weighing 22% of the weight of wastepaper recycled.

Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms.

Pollution became a popular issue after World War II, due to radioactive fallout from atomic warfare and testing. 

The development of nuclear science introduced radioactive contamination, which can remain lethally radioactive for hundreds of thousands of years. 

A pollutant is a waste material that pollutes air, water or soil. Three factors determine the severity of a pollutant: its chemical nature, the concentration and the persistence.

The major forms of pollution are listed below:

Air pollution, the release of chemicals and particulates into the atmosphere. Common gaseous pollutants include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs) and nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight. Particulate matter, or fine dust is characterized by their micrometre size PM10 to PM2.5.

Air pollution comes from both natural and man made sources.

China, United States, Russia, Mexico, and Japan are the world leaders in air pollution emissions. Principal stationary pollution sources include chemical plants, coal-fired power plants, oil refineries, petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.), PVC factories, metals production factories, plastics factories, and other heavy industry.

Main health effects on humans from some common types of pollution.

Pollution

CBSE Class 6 Science Garbage In Garbage Out Exam Notes_6

Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical system or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants, the elements of pollution, can be foreign substance or energies, or naturally occurring, when naturally occurring, they are considered contaminants when they exceed natural levels. Pollution is often classed as point source or non point source pollution. The Blacksmith Institute issues an annual list of the world’s worst polluted places. In the 2007 issues the ten top nominees are located in Azerbaijan, China, India, Peru, Russia, Ukraine and Zambia.

Forms of Pollution

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  1. The major forms of pollution are listed below along wit h the pa r ticu la r pollu ta nt s relevant to each of them:
  2. Air pollution, the release of chemicals and particulates into the atmosphere. Common gaseous pollutants incl u de ca r b on monox ide, s u l fu r diox ide, chlorofluorocarbons (CFCs) and nitrogen oxides p r od u ced b y indu s t r y a nd mot or vehic les . Phot ochemicals ozone a nd smog are created as nitrogen oxides and hydrocarbons react to sunlight. Particulate matter, or fine dust is characterized by their micrometre size PM10 to PM2.5. 
  3. Light pollution, includes light trespass, over-illumination and astronomical interference. 
  4. Littering
  5. Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as well as high- intensity sonar.
  6. Soil contamination occurs when chemicals are released intentionally, by spill or underground leakage.
  7. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and chlorinated hydrocarbons.
  8. Radioactive contamination, resulting from 20th century activities in atomic physics, such as nuclear power generation and nuclear weapons research, manufacture and deployment.
  9. Thermal pollution, is a temperature change in natural water bodies caused by human influence, such as use of water as coolant in a power plant.
  10. Visual pollution refer to the presence of overhead power lines, motorway billboards, scarred landforms (as from strip mining), open storage of trash or municipal solid waste.
  11. Water pollution, by the discharge of waste water from commercial and industrial waste (intentionally or through spills) into surface waters, discharges of untreated domestic sewage, and chemical contaminants, such as chlorine, from treated sewage, release of waste and contaminants into surface runoff flowing to surface waters (including urban runoff and agricultural runoff, which may contain chemical fertilizers and pesticides); waste disposal and leaching into ground water, eutrophication and littering.

 

Pollutants 

A pollutants is a waste material that pollutes air, water or soil. Three factors determine the severity of a pollutant its chemical nature, the concentration and the persistence.

CBSE Class 6 Science Garbage In Garbage Out Exam Notes_8

Sources and Causes

Air pollution comes from both natural and man-made sources. However, globally man-made pollutants from combustion, construction, mining, agriculture and warfare are increasingly significant in the air pollution equation.

 Motor vehicle emissions are one of the leading causes of air pollution. China, United States, Russia, India, Mexico, and Japan are the world leaders in air pollution emissions. Principal stationary pollution sources include chemical plants, coal-fired power plants, oil refineries, petrochemical plants, nuclear waste disposal activity, incinerators, large livestock farms (dairy cows, pigs, poultry, etc.), PVC factories, metals production factories, plastics factories, and other heavy industry. Agricultural air pollution comes from contemporary practices which include clear felling and burning of natural vegetation as well as spraying of pesticides and herbicides. 

About 400 million metric tons of hazardous wastes are generated each year. The United States alone produces about 250 million metric tons. Americans constitute less than 5% of the world’s population, but produce roughly 25% of the world’s CO2, and generate approximately 30% of world’s waste. In 2007, China has overtaken the United States as the world’s biggest producer of CO2, while still far behind based on per capita pollution - ranked 78th among the world’s nations. 

An industrial area, with a power plant, south of Yangzhou’s downtown, China

In February 2007, a report by the Intergovernmental Panel on Climate Change (IPCC), representing the work of 2,500 scientists, economists, and peacemakers from more than 120 countries, said that humans have been the primary cause of global warming since 1950. Humans have ways to cut greenhouse gas emissions and avoid the consequences of global warming, a major climate report concluded. But to change the climate, the transition from fossil fuels like coal and oil needs to occur within decades, according to the final report this year from the UN’s Intergovernmental Panel on Climate Change (IPCC).

Some of the more common soil contaminants are chlorinated hydrocarbons (CFH), heavy metals (such as chromium, cadmium–found in rechargeable batteries, and lead–found in lead paint, aviation fuel and still in some countries, gasoline), MTBE, zinc, arsenic and benzene. In 2001 a series of press reports culminating in a book called Fateful Harvest unveiled a widespread practice of recycling industrial by-products into fertilizer, resulting in the contamination of the soil with various metals. Ordinary municipal landfills are the source of many chemical substances entering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU. There have also been some unusual releases of polychlorinated dibenzodioxins, commonly called dioxins for simplicity, such as TCDD.

Pollution can also be the consequence of a natural disaster. For example, hurricanes often involve water contamination from sewage, and petrochemical spills from ruptured boats or automobiles. Larger scale and environmental damage is not uncommon when coastal oil rigs or refineries are involved. Some sources of pollution, such as nuclear power plants or oil tankers, can produce widespread and potentially hazardous releases when accidents occur.

In the case of noise pollution the dominant source class is the motor vehicle, producing about ninety percent of all unwanted noise worldwide.


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