Humans and Pollution Flashcards
What is pollution?
- Pollution is the addition of a substance // agent to an environment by human activity
- At a rate greater than that at which it can be rendered harmless by the environment
- Has an appreciable effect on the organisms within the environment
Pollutants are released by human activities and may be: (3)
MATTER (gases, liquids, solids) which is organic (contains carbon atoms) or inorganic
ENERGY (sound, light, heat)
LIVING ORGANISMS (invasive species // biological agents)
What are primary pollutants?
Primary pollutants are active on emission
e.g. carbon monoxide from the incomplete combustion of fossil fuels, which causes headaches + fatigue + death
What are secondary pollutants?
Secondary pollutants are formed by primary pollutants undergoing physical or chemical changes
e.g. sulphuric acid forms when sulphur trioxide reacts with water
Name of an example of something that is a mixture of primary and secondary pollutants
Photochemical smog is a mixture of primary and secondary pollutants
What is non-point source pollution?
Release of pollutants from numerous origins
e.g. gases from the exhausts on vehicles
It may be virtually impossible to detect exactly where it is coming from
How can rainwater collect non-point source pollutants that lead to eutrophication ?
- Rainwater can collect nitrates + phosphates (from fertiliser) as it infiltrates the ground // runoff from surface
- May travel kilometres before draining into lake or river
- May increase nutrient levels so much, eutrophication occurs
- Not possible to say which farmer spread the excess fertiliser
1 solution to non-point source pollution
Set limits for famers + all industries to reduce emissions and then monitor what they actually do
What is point source pollution?
Release of pollutants from a single, clearly identifiable site
e. g. A factory chimney
e. g. Wate disposal pipe of a sewage works into a river
Usually easier to manage as can be found more easily
What are Persistant Organic Pollutants (POPs) and what is the issue with them?
- Used as pesticides in past
- Resistant to breaking down + remain active in environment for a long time
- As result, they bioaccumulate in animal + human tissues and biomagnify in foodchains
Give 2 examples of Persistant Organic Pollutants
DDT
PCBs
What are 4 properties of Persistant Organic Pollutants?
- High molecular weight
- Not very soluble in water
- Highly soluble in fats + lipids // meaning they can pass through cell membranes
- Halogenated molecules, often with chlorine
What were PCBs used for?
Used widely in electrical apparatus and as coolants since the 1930s, but banned in 2001
Why were PCBs banned in 2001?
- Cause cancers + disrupt hormone function
- As they are so persistant, PCBs are found everywhere in water as well as in animal tissues, even in Arctic Circle
What are biodegradable pollutants?
- Do not persist in environment + break down quickly
- Can be broken down by decomposer organisms // light, heat
e.g. common herbicide called glyphosate used to kill weeds // it is degraded + broken down by soil organisms
