Landfills have a huge mix of different rubbish in them such as metals, whiteware, plastics, rubber, paper, food, dead animals, wood, medical waste, paint, batteries and chemicals. All of these things break down at different rates and produce gases and toxic chemicals which can escape from the landfill into the environment.
Landfills produce methane (an explosive & green house gas), and leachate (a toxic cocktail of chemicals) that can leak from a landfill when the liner fails. Old landfills were not lined but modern landfills have liners. As liners are made from plastic they don't last more then a few decades.
WASTE FACTS:
Nappies take over 75 years to break down in a landfill.
We throw away 22 million plastic bags each week in NZ.
There are 7 different types of plastic but we normally only recycle types 1,2 & 5.
189,000 tonnes of plastic is dumped into landfills each year in NZ.
Plastic bags (type 4) take up to 20 years to break down in a landfill.
A tin can takes 100 years to break down.
An aluminium can take almost 500 years to break down.
Styrofoam (like the meat trays & coffee cups) NEVER breaks down.
