How Does Mercury Get Into Fish?
Some vegetarians might claim that fish are
friends not food, I am not one of them. But what if our fishy friends are actually poisoning
us? Hey guys, Julia here for DNews Thanks to recent trends like the mediterranean
diet, fishy meals are having their heyday. Fish seems to be the perfect healthy food,
since they’re packed with omega-3s, which could be good for the heart and some claim
it’s great brain food too. Buuuut there’s always a problem in paradise.
Eating too much fish, might cause a buildup of mercury. Mercury builds up in the bodies
of smaller fish, which gets eaten by bigger fish, so the mercury builds up there, and
then THAT fish is eaten by even bigger fish so they get even more mercury… and so on
up the food chain, this process is called bioaccumulation. So mercury bioaccumulates
in bigger fish like shark or swordfish, which wind up with pretty big doses of the toxin.
But even more common fish like tuna and salmon can accumulate decent doses too. For most people this isn’t a problem, the
benefits from fish far outweigh any negatives. But mercury exposure in pregnant women could
harm the brain and nervous system of a developing fetus. Exposure might be linked to ADHD issues
in their children, according to one study published in the journal Archives of Pediatrics
& Adolescent Medicine. and the FDA recommends that pregnant and breastfeeding women avoid
eating shark, tilefish, swordfish and king mackerel, fish with the highest levels of
mercury. They also recommended limiting consumption of albacore tuna to six ounces per week. So where does all that mercury come from?
It is a natural element found throughout the environment. Some scientists think that it
could be coming from hydrothermal vents. But it’s much more likely it’s thanks to human
activity. We produce a lot of heavy metal waste from power plants and manufacturing
industries. While some safeguards are in place, some facilities have serious leaks or disposal
issues. So heavy metals like mercury get released into the air and then find their way into
water systems and head out to sea. There, the toxin builds up in fish, which
turn the mercury into a toxic form, methylmercury. According to the EPA “Nearly all fish and
shellfish contain traces of methylmercury”. Other animals are affected too, like coral.
Corals are really good at filtering out these heavy metals from the water, unfortunately,
this can also harm them. Just small amounts can kill them. But their deaths may not be
in vain! Corals have given inspiration to a group of Chinese scientists. These researchers
describe their new coral inspired material in the Journal of Colloid and Interface Science.
They made aluminum oxide nanoplates, which have proved themselves to be pretty good removals
of pollutants in past research, but not ideal. So the researchers created their nanoplates
to mimic coral’s structure and the way that they curl. By making a structure that’s
porus like coral it increases the surface area of the coral, making it absorb all that
nastiness so much better! So that could be a cool biomimicry solution
in the future – well, that along with green energy and manufacturing solutions that keep
the oceans from being polluted in the first place. But for now, the FDA recommends eating
at least two meals a week which include fish, just not any of the large species like swordfish. But what about farmed fish – is that a good
alternative or not? Trace explores that question in this video