ABSTRACT
Before it is possible to understand the effects of pollutants upon ecosystems it is essential to have an appreciation of food chains and food webs. This section is not intended to be a comprehensive discussion of food chains and webs, but simply to outline their organisation and the routes by which foreign chemicals find their way into animals and plants and more importantly concentrate up the food chain. Jonathan Swift, the eighteenth century satirist, summed up food chains admirably in this verse:
So, naturalists observe, a flea Hath smaller fleas that on him prey;
And these have smaller fleas to bite ’em And so proceed ad infinitum. Thus every poet, in his kind Is bit by him that comes behind.
