There are basically two types of pollution:
1.The right chemical in the wrong place.
2.The wrong chemical in the wrong place.
Everything is a chemical. There is not one thing you look at, touch or feel that is not a chemical of some sort. But every chemical has its place – petrol belongs in the tank in your car, not on your front lawn, for example. In your car, it does the job it was made to do, but on your front lawn, it kills the grass and smells bad.
Essentially, the right chemical in the wrong place, is a naturally occurring chemical that is a pollutant because it is somewhere where it shouldn’t be.
A good example of this is the recent oil spill in the Gulf of Mexico. The crude oil spewing out of the pipe made an awful mess, and killed wildlife, and impacted local industries.
But here’s the point – crude oil is a naturally occurring chemical. All that black oily stuff squirting out from under the ocean floor is a natural chemical – it was made over many years from decaying organic matter by bacteria – so it’s as natural as flowers in the springtime.
Unfortunately, it’s not quite as attractive as flowers – and when it finds herself in the wrong place, it can make an awful mess, as the residents of Mississippi or Prince William Sound have found out (the Exxon Valdez)
The other type of pollutant are synthetic chemicals, that find their way into the environment for one reason or another. These are unnatural chemicals, and as we will see, they can pose a great hazard due to the inability of nature to break them down. In general terms these chemicals are either insecticides, fungicides, biocides, or cleaning agents.
These chemicals, often labelled “persistent”, “recalcitrant”, or “refractory” were invented because they had some very useful property, and it was their very stability – the fact that they lasted a long time – which initially made them attractive.
Most of these chemicals were developed in the golden age of science – the 1950s – when science was seen as having the answer to all the world’s problems. Unfortunately, it was also a time when the understanding of toxicity, not only to humans, but to other forms of life, was not what it is today.
Log on tomorrow, and I’ll begin a series on the various types and sources of pollution, and the various mechanisms by which they are broken down in the environment. If you have any specific ones you would like to know about, just leave a comment and I’ll have a look at it.