Conservation - most people think conserving wildlife is a good idea. Can be complicated when conservation methods mean a disadvantage for humans, or when conserving one species harms another. E.g - people need housing, but building it can destroy habitats. The world needs alternative energy sources, but tidal barrages/hyroelectric stations can alter/destroy habitats.
The Environment Agency monitors environmental changes.
Pollutants - something added to the environment which damages it. Some unnatural, but some natural (substances introduced in large quantities or in the wrong place)
Some common pollutants are:
- s/l chemicals - oil, detergants, fertilisers, pesticides, heavy metals
- gaseous chemicals - CO2, methane, CFCs, sulfur dioxide
Some can be measured directly, and pollution can also be detected by a fall in oxygen/pH levels in water. Scientists can often judge overall level by indicator species.
E.g. - clean water: mayfly/stonefly nymphs
low level: freshwater shrimp
moderate level: waterlouse, bloodworm
high level: skudge worm, rattailed maggot
Some lichens can only be found in clean air, whilst others are sulfur tolerant or nitrogen-loving so can live in polluted areas.
Chemicals in the Food Chain
Main chemicals to be concerned about are heavy metals and pesticides.
Heavy metals: Some poisonous, some harmful in large quantities. Most from industry, vehicles.
Pesticides: poisonous chemicals to kill agricultural pests. Traces can be found on food. Can also be washed into rivers by rainfall, or spray can drift in air.
Some are banned, but there are occasinal accidents leading to high levels of pollution.
If these enter…