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Nasty chemicalsSome people talk a lot of rot about chemicals as if all chemicals are bad. Everything is made of chemicals. Some are 'good' while others are 'bad'. Water is a chemical; so is air. Some people think that if something is 'natural', then that's okay. But
some natural chemicals are very poisonous: things like sulphur dioxide (that
comes out of volcanoes) and ricin (a deadly chemical made by the castor
oil plant). The difference between these natural chemical poisons and ones
which humans have made is that life has got used to the natural poisons.
It's learned to live with them over millions of years. Some life -- certain
types of bacteria -- even eats poisons which would kill you or me.
The best known nasties are persistent organic pollutants (POPs). These include the pesticides farmers spray on food crops. POPs are very stable. They don't go away. Almost no life can break them down and make them harmless. Instead they tend to build up inside animals' bodies. This can mean they can't have babies or it can make them ill or even kill them. Perhaps you've also heard
of CFCs?
These chemicals are not toxic but they do damage the atmosphere.
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