Pollution

Pollution

the release of substances or forms of energy into the environment that cause harm, especially to living organisms

What 3 effects do the properties of pollutants have

determine the length of time it may cause a problem, level of harm it can cause and where/how far it might travel

State of matter effect

The state of a pollutant affects its ability to be dispersed by moving water or air. Solids are deposited close to the source while gases are transported easily in the atmosphere

Energy form effect

The different pollutants that are different energy forms have widely varying impacts due to the way the energy behaves

Density effect

Density affects dispersal. Denser materials require more kinetic energy to keep them suspended, so will be deposited closer to the source. Some gases are denser than air so settle close to ground if there’s insufficient wind to disperse them

Persistence

a measure of the length of time that a pollutant remains in the environment before it breaks down chemically

Biodegradation

degradation caused by living organisms, usually bacteria

Photodegradation

degradation caused by light

Thermal degradation

degradation caused by heat

Toxicity

a measure of how poisonous a substance is to living organisms. The harm is usually caused by damage to proteins, especially the inhibition of enzyme action

Specificity

a property of toxic pollutants, used to describe variations in toxicity to different groups of organisms

Specificity effect

More specific means more toxic to some groups than others. Non-specific means similar toxicities to all groups

Reactivity effect

Affects the severity of pollution caused, either increasing or reducing the problems caused as the pollutant can react and combine with others to produce secondary pollutants

Primary pollutant

a pollutant released by human activities

Secondary pollutant

a pollutant produced by chemical reactions between 1 or more primary pollutants, often with non-pollutants

Adsorption

Some pollutants can become attached to the surface of materials such as soil particles or aquatic sediments

Adsorption effect

adsorbent pollutants can be immobilised on materials but they may later be released after a period of time when their presence wasn’t obvious

Solubility in water

ability to dissolve in water

Solubility in lipids

ability to dissolve in lipids

Solubility in water effect

substances with high solubility in water are easily dispersed in water bodies. This can reduce pollutant concentration but may allow the pollutant to affect a larger area

Solubility in lipids effect

substances that dissolve in lipids may be able to pass through phospholipid cell membranes and be stored in oil/fat deposits within cells

Bioaccumulation

when a pollutant accumulates in an organism. Often involves long-term ingestion of small doses of a liposoluble pollutant

Bioaccumulation effect

a pollutant that can bioaccumulate will remain in the organism and build up over time, causing long term effects

Biomagnification

substances that can magnify up a food chain, becoming more concentrated into a progressively smaller biomass with each successful trophic level

Biomagnification effect

Allows pollutants to be passed up food chains, the higher trophic levels will ingest more of the pollutant so be impacted more

Synergism

two or more pollutants where their effects interact to create a different effect

Synergism effect

the effect created will likely be more harmful or damaging

Mutagens

agents that cause changes in the chemical structure of DNA by damaging chromosome by rearrangement of the DNA structure

Gonadic effects

a mutation in an egg, or sperm cell, or in an embryo. May cause a birth abnormality in the offspring produced

Somatic effects

a mutation in a body cell, may make it behave abnormally as the damaged DNA can’t control normal cell function, can cause cancer

Carcinogens

Mutagens that cause cancer

Carcinogenic action

cell multiplication caused by a carcinogen produces a mass of tissue called a tumour. The tumour may eventually cause health problems by preventing normal tissue function

Teratogens

cause birth abnormalities by preventing normal gene expression

Teratogenic action

they inhibit the function of proteins and enzymes that the DNA would normally have controlled. The birth abnormality can’t be inherited by future generations as the DNA structure isn’t affected

Mobility

the ability of a pollutant to move in the environment

Mobility effect

pollutants that are more mobile are likely to travel greater distances and affect larger areas, although dilution may reduce the severity of the effect

Temperature effect on degradation

most chemical reactions occur more rapidly in high temperatures. Degradable pollutants break down more rapidly at higher temperatures, but more rapid degradation can increase problems such as deoxygenation

Light levels effect on degradation

light can provide the activation energy that drives chemical reactions involving pollutants

Oxygen effect on degradation

Oxygen is involved in many chemical and biological reactions involving pollution. Examples are aerobic bacterial decomposition of sewage and oxidation of sulphide ores producing sulphur dioxide

pH effect on degradation

pH can effect solubility of substances. Many heavy metals are more soluble therefore mobile under more acidic conditions

Pollutant interactions

The behaviour of a pollutant may be affected by the presence of other pollutants such as:

• the interaction of NOx and hydrocarbons in photochemical smogs

• the combined effects of phosphates and nitrates in eutrophication

How do wind and water currents affect dispersal

the velocity + direction of air and water currents affects how far a pollutant is dispersed and how much it’s diluted

Temperature inversions

the atmosphere in the troposphere gets colder with increasing altitude. Warm pollutant gases are less dense and more buoyant than the cooler surrounding air. They rise, disperse and become diluted

How can valleys allow temperature inversions to form

colder denser air can collect

How can low wind velocity allow temperature inversions to form

the air layers with different temperatures don’t mix

How can cloudless skies allow temperature inversions to form

infrared energy can be radiated from the ground, allowing the ground to cool down

How can mist/fog during the day allow temperature inversions to form

water vapour condenses in the cooler ground layer and has a high albedo, reflecting sunlight and slowing the heating of the ground that would cause the temperature inversion to be broken down

Critical pathway analysis

prediction of the movement of potential pollutants in the environment to assess the severity and location of the pollution that may occur

What is CPA mostly used for

monitoring the dispersal of radioactive waste charges

How is the accuracy of CPA predictions checked

using environmental sampling

Critical group monitoring

a specific method of assessing the risk of public exposure to pollutants.

Critical group

the members of the public who, due to their lifestyle, are most at risk

What environmental factors affect the dispersal of pollutants

air quality, meteorological conditions, hydrology, emission source

How can tidal cycle affect pollution

emissions into tidal rivers when the tide is coming in will be carried upstream. Emissions when the tide is going out will be carried out to sea where they will disperse

How can temperature inversions effect pollution

atmospheric emissions during a temperature inversion are less likely to disperse. Polluting activities may be restricted in some cities during temperature inversions e.g. industrial combustion

The polluter pays principle

if the organisation/person that causes pollution is responsible for any problems caused, there is an obligation to prevent it. Costs of preventing damage caused < costs of damage = financial incentive to prevent it

The precautionary principle

assumes a waste will cause pollution if released. Safer than releasing a waste that hasn’t been analysed in the hope that it’s safe and waiting for problems to occur. Being unaware of a problem that isn’t yet understood isn’t an excuse and doesn’t reduce responsibility

ALARA meaning

emissions should be as low as reasonably achievable to control pollution

BATNEEC meaning

selecting equipment to control pollution that is the best available technology, not entailing excessive cost

Smoke

a toxic atmospheric pollutant made up of the atmospheric particulates produced by incomplete combustion of carbon-based materials

PM10

particulate matter less than 10 microns in diameter

PM5

particulate matter less than 5 microns in diameter

PM1

particulate matter less than 1 micron in diameter

Why is particle size important

smaller particles remain in the atmosphere for longer so are more likely to be inhaled

Which toxic chemicals can be found in smoke

fluorides, aluminium, lead, acids and organic compounds