Scientists thought that a dangerous chemical,
that was used in the 60s in among others pesticides and plastics, was no longer
harming the sea life. But recent studies have made clear that they still do.
The
dangerous chemicals are so-called polychlorinated biphenyls. These chemicals
don’t easily break down or degrade, making them very useful in the chemical
industry. This is also the reason they were widely used in the 60s, until they
turned out to be really dangerous. Polychlorinated biphenyls can cause rashes,
liver damage and cancer. When this was discovered, the chemicals were quickly
forbidden, and it seemed that the biphenyls disappeared quickly from the oceans.
But the amount of biphenyls in the oceans can still cause harm to sea life. Because
the chemicals don’t easily break down, the amount of these chemicals has
stopped decreasing. Scientists are trying to find a way to get rid of the
excess polychlorinated biphenyls anyway.
Poison accumulates in orcas
The
polychlorinated biphenyls especially affects the sea animals that are high in
the food chain. The explanation for this is that animals can’t digest the
biphenyls. So, when a small fish eats plankton that has the chemicals in it,
the biphenyls end up in the flesh of the fish. When that small fish then gets
eaten by a larger fish, like a mackerel, that fish also eats all the chemicals
from all the plankton that the smaller fish ate. And the mackerel can’t digest
it either. Then, an even larger fish, like a tuna, eats the mackerel. And the
tuna also eats all the biphenyls eaten by all the mackerels it ate. So the
amount of polychlorinated biphenyls in the food increases if you go higher up
the food chain. For the animal at the top of the food chain, for example a
shark or an orca, that amount can be so high that the shark or orca dies.
Remove before 2028
With new
studies, scientists hope to find out how the polychlorinated biphenyls move
through the oceans. If they know this, they can predict where sea life will be
most affected by the chemicals, and where they can try to remove the biphenyls
from the oceans best. With this new knowledge, scientists hope to significantly
reduce the amount of polychlorinated biphenyls in the oceans by 2028, which
will benefit both sea life and people alike.
Click here to read more biology posts.
Click here to read more chemistry posts.
Sources:
No comments:
Post a Comment
Great that you want to comment! Please write something relevant and non-offending.