Waste and pollution: trace the exposure route
| English | 中文 | Pinyin |
|---|---|---|
| pollution/pəˈluːʃn/ | 污染 | wū rǎn |
| runoff/ˈrʌnɒf/ | 径流 | jìng liú |
What would explain this observation?
- Waste placed on land can later enter water. Classify the source and trace how organisms encounter it rather than assuming pollution 污染 stays where it begins.
- Start with a prediction. State the quantities or features you would compare, then decide what evidence could distinguish two explanations.
Build the model
- More people and greater resource consumption can produce more waste. If waste and chemicals are not managed appropriately, pollution affects water, air and land. Water can receive sewage, fertilisers and toxic chemicals. Air pollution includes smoke and acidic gases. Land pollution includes landfill and toxic substances.
- pollution: Harmful contamination or environmental change from substances or waste; runoff 径流: Water moving over land and carrying materials into waterways.
Which chain explains one fertiliser-runoff effect?
Pollutants can kill plants and animals or change the conditions needed for survival, reducing biodiversity. Fertiliser runoff can stimulate excessive algal growth; subsequent microbial decomposition can reduce dissolved oxygen and affect aquatic animals. This mechanism differs from a toxic substance directly poisoning an organism.
Match each technical term to its precise meaning.
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Pollutants can kill plants and animals or change the conditions needed for survival, reducing biodiversity. Fertiliser runoff can stimulate excessive algal growth; subsequent microbial decomposition can reduce dissolved oxygen and affect aquatic animals. This mechanism differs from a toxic substance directly poisoning an organism.
- Analyse a supplied source → movement → exposure → effect chain. Compare upstream/downstream records or matched sites, identifying other possible causes. Classroom investigations use prepared water-quality records or safe approved sampling, not sewage handling, toxic chemicals or deliberate pollution.
Which two habits make the investigation or model in this case more defensible?
Analyse a supplied source → movement → exposure → effect chain. Compare upstream/downstream records or matched sites, identifying other possible causes. Classroom investigations use prepared water-quality records or safe approved sampling, not sewage handling, toxic chemicals or deliberate pollution.
Work from known quantities
- State the known values and their units. Choose the relation because its assumptions fit this case, then rearrange before substitution.
- Known: a fictional waste account contains 120 kg generated and 45 kg recovered for reuse or recycling. Unrecovered amount = 75 kg; recovery percentage = 45/120×100 = 37.5%. Unrecovered is not automatically all released as pollution: controlled treatment and disposal must also be considered.
A model generates 160 kg of waste and recovers 60 kg. Calculate recovery percentage. Use the same sequence: known quantities → model → relation → substitution → unit and interpretation.
A model generates 160 kg of waste and recovers 60 kg. Calculate recovery percentage.
The result is 37.5 %. Known: a fictional waste account contains 120 kg generated and 45 kg recovered for reuse or recycling. Unrecovered amount = 75 kg; recovery percentage = 45/120×100 = 37.5%. Unrecovered is not automatically all released as pollution: controlled treatment and disposal must also be considered.
Check the conclusion and its limits
- Pollution categories describe routes, not a rule that one substance affects only one medium. More recycling does not remove every production impact. An oxygen decline in water needs a supported mechanism; it is not proof that all pollution acts identically.
- Return to the original observation. Explain what the result supports, which conditions it assumes, and one way to test a competing explanation.
Every unrecycled kilogram is necessarily released directly into a river. This claim is false: Pollution categories describe routes, not a rule that one substance affects only one medium. More recycling does not remove every production impact. An oxygen decline in water needs a supported mechanism; it is not proof that all pollution acts identically.
Waste and pollution: trace the exposure route: Pollutants can kill plants and animals or change the conditions needed for survival, reducing biodiversity. Fertiliser runoff can stimulate excessive algal growth; subsequent microbial decomposition can reduce dissolved oxygen and affect aquatic animals. This mechanism differs from a toxic substance directly poisoning an organism.
Every unrecycled kilogram is necessarily released directly into a river.
Pollution categories describe routes, not a rule that one substance affects only one medium. More recycling does not remove every production impact. An oxygen decline in water needs a supported mechanism; it is not proof that all pollution acts identically.
Harmful contamination or environmental change from substances or waste: write the technical term.
pollution means Harmful contamination or environmental change from substances or waste.