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7.3.Why does the level of dissolved oxygen in the river then increase again further downstream?(2)

7.4.Give TWO possible reasons why sewage would be discharged into river systems in a developing urban environment.(4)

7.5.Name one positive and one negative effect that “quite heavy pollution” could have on a rural farming community living at point X downthe river.(2)

Question 8

8.1Humans can influence the environment in ONE of the following positive ways.

ABurning fossil fuels




8.2Pollutant gases have an adverse effect on the environment and on our health. The amounts of these gases have been steadily increasing over the years. Thetable below shows the source and amount of some pollutant gases produced by human activities.

Pollutant gas


Amount produced per year (millions of tons)

Carbon dioxide Vehicle exhausts 350
Sulphur dioxide Burning coal and oil, industry 200
Nitrogen oxide Vehicle exhaust 55

8.3.Which ONE of the following statements is correct?

A150 million tons of nitrogen oxide is produced.

BCarbon monoxide is produced by industry.

CSulphur dioxide is produced by vehicle exhaust.

DCarbon monoxide is the gas produced in the largest amount.

8.4.Possible measures for the reduction of air pollution would NOT include

Aproviding subsidies for solar panels

Bproviding subsidies for truck drivers

Crewards for cleaner production by industries

Dimproving the public transport system

8.5Adding harmful substances to the environment is termed





Question 9

The map below shows a region of coastline close to where a giant oil tanker was wrecked at sea. The shallow waters of the coastline provided a rich source ofedible crabs. Oil does not kill the crabs but harm their flesh, making them inedible and they cannot be sold. Samples of crabs were collected at sites A toD. The number of crabs is indicated by the size of the circle. The extent of the shaded part at each site represents the proportion of crabs with diseasedflesh after the disaster.

9.1Which sample site (A to D) had the highest number of crabs? (1)

9.2.In which sample site was the crabs only rarely found?(1)

9.3Name the agent of pollution that affected the crabs.(1)

9.4In which sample site was the most crabs affected compared to the population size? (1)

9.5Explain your answer to QUESTION 2.4(2)

9.6.List TWO strategies that could reduce the effects of oil pollution at sea. (2)

Discussion points

The tragedy of the commons

From: http://cnx.org/content/m16743/latest/?collection=col10548/latest (AP Environmental Science: Environmental Ethics) from Connexions

In his essay, The Tragedy of the Commons, Garrett Hardin (1968) looked at what happens when humans do not limit their actions by including the land as part oftheir ethic. The tragedy of the commons develops in the following way: Picture a pasture open to all. It is to be expected that each herdsman will try to keepas many cattle as possible on the commons. Such an arrangement may work satisfactorily for centuries, because tribal wars, poaching and disease keepthe numbers of both man and beast well below the carrying capacity of the land. Finally, however, comes the day of reckoning (i.e., the day when the long-desired goal of social stability becomes a reality). At this point, the inherent logic of the commons remorselessly generates tragedy.

As a rational being, each herdsman seeks to maximize his gain. Explicitly or implicitly, more or less consciously, he asks: "What is the utility to me ofadding one more animal to my herd?" This utility has both negative and positive components. The positive component is a function of the increment of oneanimal. Since the herdsman receives all the proceeds from the sale of the additional animal, the positive utility is nearly +1. The negative component isa function of the additional overgrazing created by one more animal. However, as the effects of overgrazing are shared by all of the herdsmen, the negativeutility for any particular decision-making herdsman is only a fraction of -1.

The sum of the utilities leads the rational herdsman to conclude that the only sensible course for him to pursue is to add another animal to his herd, andthen another, and so forth. However, this same conclusion is reached by each and every rational herdsman sharing the commons. Therein lies the tragedy: eachman is locked into a system that compels him to increase his herd, without limit, in a world that is limited. Ruin is the destination toward which all menrush, each pursuing his own best interest in a society that believes in the freedom of the commons. Freedom in the commons brings ruin to all.

Hardin went on to apply the situation to modern commons. The public must deal with the overgrazing of public lands, the overuse of public forests and parksand the depletion of fish populations in the ocean. Individuals and companies are restricted from using a river as a common dumping ground for sewage andfrom fouling the air with pollution. Hardin also strongly recommended restraining population growth.

The "Tragedy of the Commons" is applicable to the environmental problem of global warming. The atmosphere is certainly a commons into which many countriesare dumping excess carbon dioxide from the burning of fossil fuels. Although we know that the generation of greenhouse gases will have damaging effects uponthe entire globe, we continue to burn fossil fuels. As a country, the immediate benefit from the continued use of fossil fuels is seen as a positive component.All countries, however, will share the negative long-term effects.

Additional resources

Plants can tell us about climate change

See how the general public are helping scientists monitor climate change by observing the timing of leafing, flowering, and fruiting of plants (plantphenophases).

Project Budburst http://neoninc.org/budburst/

Ecology site


The Story of Stuff

To see how humans can affect the environment: watch “The story of stuff”: http://youtu.be/9GorqroigqM


Question 1





Question 2

2.1.Sample site A

2.2.Sample site D


2.4.Sample B

2.5.Sample B has greater shaded portion

2.6.Regular service of oil tankers

Legislation on the amount of oil the oil tankers transport

Monitoring of travel routes

Use bacteria to dissolve the oil spill


Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Comment on the ozone depletion over the period of 1982 to 1996
Mpho Reply

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Source:  OpenStax, Siyavula: life sciences grade 10. OpenStax CNX. Apr 11, 2012 Download for free at http://cnx.org/content/col11410/1.3
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