Unit 3: Properties of Pollutants
Teacher recommended
?- Created by: rosieevie
- Created on: 11-01-15 14:59
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- Properties of Pollutants
- Toxicity
- Poisonous and harms biological processes - damaging proteins
- Carbon monoxide, lead, DDT
- Not all pollutants are toxic (some change environmental factors)
- Specificity
- Different organisms have different sensitivities to substances
- Effective for pesticides - kills target species but not others
- Persistence
- The longer the pollutant remains in environment, more harm it can do
- Not used for substances that never break down (non-biodegradable)
- CFCs, DDT, Heavy metals
- Biodegradability
- Rate is affected by environmental factors e.g. temp, oxygen
- Biodegradable - sewage, paper
- Mobility
- More mobile pollutants travel longer distances - affect further places
- More likely to become diluted and less locally harmful
- CFCs, sulphur dioxide (acid rain), smoke, suspended solids
- Solubility
- Water-soluble - can be mobile in hydrosphere e.g. sulphur dioxide, nitrates
- Lipo-soluble - dissolves in lipids so can be stored in body for long periods e.g. dioxins
- Bioaccumulation
- Chronic exposure to small doses over long periods of time
- Liposoluble pollutants more likely to bioaccumulate
- DDT, heavy metals
- Biomagnification
- Stored pollutants in animals may be eaten by animals in next tropic level
- Predators eat lots so more concentrated in them
- Synergism
- Oxides of nitrogen and sulphur dioxide, zinc and cadmium
- Two pollutants produce greater effect
- Difficult to predict - not possible to test all combinations
- Mutagenicity
- DNA changes in gametes may cause birth abnormalities
- DNA changes in body cells may cause cancer
- Ionising radiation, asbestos
- Carcinogenicity
- Cells produced unable to carry out normal functions = cancerous tumors
- Asbestos, DDT
- Teratogenicity
- Birth abnormalities are non-inherited and cannot be passed on as DNA is unaltered
- Inhibit enzyme/protein function in embryo
- Herbicides, mercury
- Toxicity
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