Several decades ago scientists were sure that since the World Ocean covers 75% of Earth surface, it would simply dissolve all pollutants. Their concentration would be insignificantly small, so it's not dangerous for humans. As a matter of fact, things turn out to be a little bit more complicated.
The Dirt Won't Go Away
WWF experts calculated the amount of pollutants dumped in the Oceans annually. It equals to total amount of pollutants that was present there 50 years ago. Besides that, whenever the scientists assumed that water would dissolve all pollutants, they never thought poison would all reach the oceanic food chain. Guess who's on top of it? It's us, humans...
Prior to 1970s there were no regulations on chemicals that could be disposed in the oceans, so different countries would dump pesticides, nuclear waste and chemical weapons straight to the sea. The British were the ones to get concerned firsthand: in 1972 they developed a national convention on waste disposal in the oceans. By 1996 the list of substances that could not be discharged in the oceans was significantly supplemented.
Poisonous Foods
The bottom of the food chain is plancton – microscopic crustaceans and algae. They tend to store some poisonous substances, and over a certain period of time concentration of toxins in plancton reaches even higher levels than that dissolved in water. Tiny fishes, polyps and jellyfish nourish on poisoned plankton. Therefore, the higher the creature is in the food chain, the higher is the concentration of toxins in its tissues. For example, the amount of poisonous substances in tissues of polar bears, sharks and seals might exceed that in the environment by million times!
Toxins are mostly stored in lipids, or adipous tissues. This is why fatty sorts of fish, like salmon, tuna and mackerel, are particularly dangerous. Food poisoning is probably the lightest consequence that we might get from the toxins with which we pollute the oceans. Delayed consequences may include cancer, psychic disorders, immune defficiency and fertility problems.
So it is obvious that problems of oceanic pollution affect us directly. Water could wash away practically anything, but it's the living beings who suffer from our hazardous activities. And then it all boomerangs to hit us.
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