Pollution Sources, Pathways And Receptors

Question 1

What is the definition of pollution

Answer 1

The deliberate or accidental introduction of contaminants (pollutants) into the environment which causes adverse changes.

Pollutants may be substances, or energy

Pollutants can be natural such as lava flow from an active volcano, or overflow from a flooding river

Question 2

Pollution definitions from environmental permitting, England and Wales - 2010 - water

Answer 2

Pollution, in relation to a water discharge activity, or groundwater activity, means the direct or indirect introduction as a result of humans activity of substances, or hear into the air, water or land which may:

• be harmful to human health, or the quality of aquatic or (terrestrial ecosystems dependent on aquatic ecosystems)
• result in damage to material property
• impair or interfere with amenities, or other legitimate uses of the environment

Question 3

Pollution definitions from environmental permitting, England and Wales - 2010 - non water

Answer 3

Pollution - other than water discharge - means any emission as a result of human activity which:

• may be harmful to human health or quality of environment
• cause offence to a human sense - e.g. noise, smell
• result in damage to material property
• impair to interfere with other legitimate uses of the environment

Question 4

What is the difference between primary and secondary pollutants

Answer 4

Primary - produced directly from a process, e.g. ash from a volcano,m or carbon dioxide from a car exhaust

Secondary - not emitted directly but produced by a chemical reaction between primary pollutants, e.g. acid rain, ground level ozone

Question 5

What are inorganic compounds

Answer 5

These materials do not contain carbon. They include heavy metals such as cadmium, lead, mercury and arsenic

Question 6

What are organic compounds

Answer 6

These materials contain carbon. An organic compound is any, natural or synthetic molecule or compound containing carbon. They include

• Glucose, fructose
• DDT - powerful, now largely banned insecticide
• PCBs - polychlorinated biphenyls - historically widely used as insulating oils

Question 7

Define air pollution

Answer 7

The release of chemicals, including particulates and aerosols into the atmosphere

Question 8

Define radioactive pollution

Answer 8

The release of radioactive substances on surfaces, or within solids, liquids or gases (including the human body), where there presence is unintended or undesirable

Question 9

What are organometallic compounds

Answer 9

These are formed when metals react with organic molecules.

E.g. when combined with organic molecules, elemental mercury forms methylmercury, a neurotoxin that affects the central nervous system. Methyl mercury can also bioaccumulate in the food chain.

Tin is an example of a non toxic metal (used as a lining on food containers) which becomes toxic when it bonds with organic molecules to form TBT. TBT is widely used as a biocide in antifouling marine paints to discourage growth of organisms such as barnacles. However, it is extremely toxic to crustaceans such as lobsters. TBT exposure can lead to the development of male characteristics in female snail and bivalve species.

Question 10

Definition of land pollution

Answer 10

The release of chemicals onto, or into soil, for example via spills or leakage.

Question 11

Definition of Thermal Pollution

Answer 11

Sometimes called thermal enrichment, is the degradation of water quality by any process that changes ambient water temperature. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers.

Also release of chemicals which are warmer or cooler than the receiving water (usually aqueous solutions)

Question 12

What is light pollution

Answer 12

The release of excess light, including light trespass, over illumination and astronomical interference

Question 13

Why is light pollution harmful

Answer 13

• Harms animals whose life cycles are dependent on the dark
• Altering our biochemical rhythms that normally ebb and flow with natural light
• Lost our connection to the night time skies, and the tapestries into which our ancestors wove their star studded stories, timed the planting and harvesting of crops, and deduced the physical laws governing the universe.

99% of EU and USA experience some amount of light pollution

Question 14

Definition of noise pollution

Answer 14

Release of excess or unpleasant sound. Typical sources include roadways, aircraft, industry, and high intensity sonar.

Question 15

What is visual pollution

Answer 15

Visual pollution is an aesthetic issue and therefore highly subjective . Typical examples are power lines, roadside billboards, fly tipping and scarred former industrial landscapes

Question 16

Definition of water pollution

Answer 16

Release of chemicals into bodies of water

Question 17

What must a pollutant do to become harmful (and create pollution)

Answer 17

It must come from a source, travel via a pathway and be received by a receptor. If a receptor does not receive it, there can be no pollution

E.g.spill from oil drum, travels through soil, ends up in river, stream, lake

Question 18

What is leaching

Answer 18

In agriculture, leaching is the loss of water soluble plant nutrients from the soil, during rain and irrigation

Question 19

Name some factors that determine the effects of a pollutant

Answer 19

• Form - solid, liquid, gas or energy
• Concentration in the environment
• Chemical and/or biological properties
• Environmental persistence and ability to bioaccumulate
• The ‘quality’ of the receptor, e.g. stability of the ecosystem, health of an individual, materialism of construction for property etc

Question 20

Under normal atmospheric pressure and ambient temperatures, how much dissolved oxygen should be contain between its molecules

Answer 20

Water should contain 10 mg/l of oxygen to be saturated.

Concentration will vary with pressure and temperature, but if it drops by 50% to 5 mg/l fish will become distressed and die

Question 21

Why is organic matter a water pollutant

Answer 21

Organic matter is naturally present in surface water from decaying vegetation and runoff from field, but if levels rise significantly, oxygen from the water is rapidly consumes due to the action of aerobic bacteria

Question 22

examples or water polluting organic matter

Answer 22

• Sewage
• Farm Slurry (manure and water)
• Industrial discharges, or spills of organic substances such as milk from farms or tankers

Excesses in water is referred to as high organic load. Under normal circumstances the consumed oxygen is replaced at the surface, but in a high organic load the exchange rate is too low.

High temps and low flows make it worse

Question 23

When are water sources most vulnerable to deoxygenation

Answer 23

At night. During the day photosynthesis helps with the oxygen replenishment, but at night this stops. As aquatic plants and organisms continue to respire, this depletes the oxygen

Question 24

What is the BOD test

Answer 24

Biological demand test.

Determines the level of organic pollutants in the water.

Question 25

How does a BOD test work

Answer 25

A water sample is seeded microorganisms and stored for 5 days in a dark room at 20 degrees to prevent oxygen production Most pristine rivers will have a BOD level below 1 mg/l. Moderately polluted rivers have values in the range of 2 - 8 mg/l. An alternative and quicker test is the COD test - chemical oxygen demand

Question 26

What is a COD test

Answer 26

Commonly used to quickly provide an indirect measure on water pollution, as quicker than a BOD. Uses a specific indicate reagent. Is less specific

Question 27

Why is oil a water deoxygenating pollutant

Answer 27

Oil forms a layer on the surface, restricting or even preventing oxygen exchange. May also coat aquatic plant leaves inhibiting photosynthesis

Question 28

Why are pesticides harmful as a water pollutant

Answer 28

Pesticides used in agriculture and horticulture may reach water courses, through run off or drift, both diffuse sources. They remain active in water causing damage to food webs; both target and non target species may be killed.

Question 29

What is leachate

Answer 29

A leachate is any liquid that, in the course of passing through matter, extracts soluble, or suspended solids, or any other component of the material through which it has passed.

Question 30

Why is ‘flow rate’ a pollutant

Answer 30

This input of material, even clean water, from a point source with a high flow rate may cause scarification of banks and river beds, releasing buried pollutants and disturbing suspended solids.

Question 31

Why are nitrates and phosphates a water pollutant

Answer 31

These are normally introduced from a diffuse source, for example fertiliser runoff. Excess nitrates may be produced following ammonia ingress The resultant excessive growth of water plants, notably algae, restricts oxygen exchange. Algae decay further reduces oxygen levels as eutrophication progresses.

Question 32

Define Thermal pollution (water)

Answer 32

Water is used as a coolant in power stations. If the water is returned to water courses without re-cooling, it may lead to localised increased in water temp and decreased oxygen levels. If prolonged, may promote growth of bacteria and algae. Can also prevent breeding and extreme temps may result in thermal shock, killing fish and invertebrates.

Question 33

Why are ‘Suspended Solids’ a water pollutant

Answer 33

E.g from construction activities, wind blown dust all increase turbidity (cloudiness). Moderate level can restrict fish gills, inhibit hunting behaviour and settle on plants reducing photosynthesis Once on riverbed can bury bottom dwelling organisms, leading to lack of food for feeders Sediment deposits can bury organic matter, resulting in anaerobic decomposition, leading to toxic methane and hydrogen gases Breeding grounds can be destroyed

Question 34

How are acids and alkalis harmful as water pollutants

Answer 34

Normal pH for fish and aquatic animals is around 7. Moderate changes can cause habitat changes, the creation of secondary pollutants and result in death. Niche species are especially vulnerable.

Question 35

What are the two main oxides of sulphur (Air pollution)

Answer 35

Sulphur Dioxide - SO2 - Known as SOx (most common) Sulphur Trioxide - SO3 - Known as SOX

Question 36

What is Sulphur Dioxide

Answer 36

- Most common of oxides of sulphur as air pollution - SO2 - Produced naturally when sulphur containing compounds are heated in the presence of oxygen (volcano eruptions) - Produced anthropogenically through refining metal ores containing sulphides , and combustion of fossil fuels which contain sulphur compounds as impurities

Question 37

What are the impacts of Sulphur Dioxide

Answer 37

- Long term expose can cause lung damage and damage to plants - Directly toxic and high concentrations can cause death - dissolves in water vapour, and water in cell tissue to form sulphuric acids and sulphurous - Short terms exposure causes eye irritation

Question 38

Effects of Sulphur dissolving in water vapour

Answer 38

forms gaseous aside solicitor with oxides of nitrogen compounds which falls as acid rain. Consequences of this are: - dissolution of metals form spoils leading to soil and water pollution - Acidification of Rivers and seas leading to localised habitat damage - Death of coniferous trees - Damage to steel structures and building made of rocks, limestone and marble which contain calcium carbonate. Acids in the rain react with the calcium compounds and create potentially toxic levels of gypsum

Question 39

What are the three oxides of nitrogen

Answer 39

Nitrous Oxide - N2O - Predominantly formed through microbial activity and not a significant pollutant, although is an ozone depleting compound Primary pollutants - involved in formation of ground level smog: Nitric Oxide - NO - Formed during production of coal and in vehicle exhausts Nitrogen Dioxide - NO2 - Formed during production of coal and in vehicle exhausts Collectively known as NOX. Also contribute to acid rain

Question 40

What are the two oxides of carbon

Answer 40

``` Carbon Monoxide (asphyxiant and highly reactive pollutant in ground level smog) Carbon Dioxide ``` Principle source of both is burning fossil fuels,

Question 41

Chemical formula of methane

Answer 41

CO4 GHGS, main constituent of natural gas, occurs with crude oil and coal mines. Also produced in anaerobic digestion

Question 42

What are volatile organic compounds

Answer 42

VOC is a term used to describe a range of unrelated solvents which are liquid at normal temperatures and pressures, but release vapour into the atmosphere by evaporation. May contain carbon, oxygen, hydrogen, chlorine and sulphur Most common are petrol and diesel, paints, solvents, glues. These compounds are used in manufacturing of plastics, cosmetics, pharmaceuticals, paints, varnishes, adhesives, and antifreeze. These react with sunlight to produce secondary pollutants - O3 and PANs Pans and O3 cause eye irritation and damaged lung tissue

Question 43

What is smog made up of

Answer 43

Smog - Smoke + Fog - visible air pollution Composed of nitrogen oxides, sulphur oxides, smoke and particulate matter, ozone’s, Marion monoxide Comes from Coal emissions Vehicular emissions Industrial emissions Forest and agricultural fires

Question 44

What is modern smog

Answer 44

Type of air pollution derived from vehicular emissions and industrial emissions that react in the atmosphere with sunlight to form secondary pollutants- they form photochemical smog

Question 45

What is a temperature inversion

Answer 45

Normally we have cold temp on top and low temp below. This inverts, and the new warm air on top traps in the smog. We cannot control the inversions as these are weather events,but we can control the content of the smog.

Question 46

What is particulate matter

Answer 46

This refers to a wide range of substances including: ``` Dust Grit Fibres Aerosols Mists Vapours Fumes ```

Question 47

How does particulate matter cause damage

Answer 47

Depends on size and properties PM2.5 - matter smaller than 2.5 microns diameter PM10 - Matter smaller than 10 microns diameter Some heavy metals are toxic, some fibres can cause disabling lung conditions. Effects of inhaling are: - asthma - lung cancer - cardiovascular disease - respiratory issues - birth defects - premature death

Question 48

How is Ozone produced (o3)

Answer 48

By the interaction of UV rays which cause oxygen molecules to split and recombine to form O3. This layer absorbs further UV, preventing it from reaching the earths surface

Question 49

Effects of excessive UV light (through historic depletion of Ozone layer)

Answer 49

Increased sunburn and skin cancer Increased ground level ozone Reduces photosynthesis in plants Cyanobacteria are particularly sensitive Seasonal holes in the ozone layer form in the Antarctic during the polar winter.

Question 50

What is/was cause of stratospheric ozone depletion

Answer 50

Release of synthetic compounds: - chlorofluorocarbons - CFCs - Hydrochlorofluourocarbons - HCFCs - Halon - Methly chloroform These compounds break down in the atmosphere to form halogen atoms such as chlorine and bromine which in turn break down Ozone N2O is a naturally occurring odeon depleter and therefore harder to restrict as per Montreal protocol

Question 51

What was the Montreal Protocol

Answer 51

International agreement in 1987 and subsequent amendments to restrict manufacture and use of key substances (CFCs, HCFCs, Halon, Methyl Chloroform).

Question 52

What is photochemical smog

Answer 52

High levels of O3 and Nitrogen oxides in the atmosphere, caused by the action of sunlight on primary pollutants These secondary pollutants can damage and weaken crops, decrease yield and make them more susceptible to insects