Every since a big black object taught some monkeys how to beat each other the head with sticks Human Beings have been fighting their way to top of the food chain.

For a while some of the larger animals could kick the shit out of us, mainly due to owning lots of teeth and claws. Luckily we invented guns so could pick off the nasty ones at a distance.

The sea still presents us with a few problems of course, there's some right vicious bastards in there and they're quite difficult to shoot... But nearly all land animals know that they should run like buggery when they see one of us coming.

Not only do we poses an amazing set of omnivorous teeth which allow to munch animals as easily as lettuce, we've also invented knifes, folks, chopsticks, meat cleavers and abattoirs so no animal is too large or too tough for us to eat.

So we're there, we're at the top. We rule.

Unfortunately it's no longer such a good thing to be the king of the mountain. Since the industrial revolution and a large amount of chimneys pumping out various nasty substances we've been poisoning the food chain. Heavy metals get farted up into the atmosphere only to end up in the oceans, and the sea bed, via rain.

Mercury is a potent neurotoxin, a cause of cancers, birth abnormalities, fatigue, depression, madness and rather nasty headaches. Studies of mercury levels in fish show that the higher up the food chain you get, the higher the level of mercury. Bigger fish, that eat other fish are full of it... Tuna, swordfish, sharks, dolphins and whales are getting through a lot of aspirin these days.

More than forty states in the US have now issued health "advisories" about fish and in June California sued three tuna-canning companies for failing to give "clear and reasonable" warning before exposing people to "known carcinogens or reproductive toxins".

In the UK, the Food Standards Agency tells us that men and boys should eat no more than one to four portions or oily fish per week. However women of child bearing age should eat no more than two portions a week and they should not eat marlin, shark or sword-fish, neither should children.

Of course, these guidelines are all based on the idea of a 'safe' level of mercury consumption, which has never really been established and it's debatable whether or not the idea of any level of Mercury consumption could be deemed 'safe'.

Fish aren't just riddled with mercury and other toxins such as polychlorinated biphenyls and flame-retardant chemicals, that have recently be shown to have a rather nasty effect on the memory and IQ... In May this year, Science reported that all those carrier bags we chuck out, more than 500 billion carrier bags a year, don’t just 'rot away', most end up as ground-up microscopic 'dirt' which finds it way to the ocean floor. Unfortunately lugworms and barnacles don’t get the Observer Food Monthly and they munch away on this Tesco’s goodness... Bingo, it’s in the food chain, and look who’s at the top...

Recently Alun Michael MP, our Environment Minister, had a blood test and thirty three chemicals and toxins were found, 32 per cent of the 103 chemicals tested for. Unfortunately we're not just poisoning MPs, we've poisoned the root of the food chain, the seas, and the toxins, heavy metals and bits of plastic just work they’re way up to the top.

Oh, and just in case you thought you might be able to avoid filling up on mercury, polychlorinated biphenyls and little bits of plastic bag by eating farmed fish, in January US researchers confirmed that farmed salmon contains many more toxic chemicals than wild salmon.

There's a theory that the fall of the Rome was mainly due to the fact that they poisoned themselves with their very clever lead piping, which caused reduced IQs, plummeting fertility and a propensity to violence and orgy. We're already poisoning ourselves, but this time it isn’t confined to a single city, there's no escape.

Maybe it’s time to head back down that food chain…

 http://www.wwf.org.uk/chemicals/
 http://www.food.gov.uk/multimedia/pdfs/cotstatementmercuryfish.PDF