Mercury rising?


There has been some interest in the popular press about Thai ladies and mercury.  The most used cosmetics in Thailand are whitening creams, and many skin whiteners contain mercury, even though this substance is banned.

Mercury works by blocking the production of skin-coloring melanin – but it also has nasty side effects.  Mercury and mercurial compounds can be absorbed into the body by inhalation of the vapors, ingestion, or skin contact.  As a poison, the damaging effects of mercury are subtle and cumulative, building up over time.

When absorbed, mercury has been discovered in blood, urine, bile, sweat, saliva, and milk.  It has also been discovered in the brain, bones, the cellular tissue, in serous membranes, in the parts close to the joints, and in the lungs and liver.

The symptoms of mercury poisoning include emotional disturbances, unsteadiness, inflammation of the mouth and gums, general fatigue, memory loss, forgetfulness and headaches.  Excess mercury in the system has been known to cause kidney problems (membranous nephropathy).

Despite legislation, research by consumer groups has found in Thailand that up to 20 percent of whitening creams are highly contaminated with mercury.

Of course, this is nothing new, nor is it just a local problem.  In May 2010, the Chicago Tribune had 50 skin-lightening creams tested at a lab (most of the creams were bought in stores, a few were ordered online).  Six were found to contain illegal amounts of mercury.  In August 2011, Philippine watchdog group EcoWaste Coalition conducted a test of 12 brands of whitening creams.  11 tested positive for high levels of mercury.

One reason why mercury keeps on being used is that it is effective in lightening dark spots and stubborn pigmentation but has a high remission rate, requiring the user to keep using the cream, before they turn dark once more.

However, there is another problem with mercury, and that is not an “adult” problem, but one where mercury affects the fetus.

The effects of small doses of mercury on adults is not great, though absorption should be avoided as much as possible, but the same cannot be said about the effects on the fetus.  It appears that the unborn is more sensitive than the adult and subtle delays in achieving the usual milestones result from the exposure to mercury in the womb.

One apparently contradictory problem occurs with dieticians’ recommendations that everyone should eat a couple of portions of fish each week, but unfortunately, it is the fish that have the mercury as the unwanted addition.  Not that the ocean bed is full of discarded mercury thermometers, it is just that mercury is a naturally occurring chemical compound, and fish are good at absorbing it.

The other interesting fact is that not all species of fish carry the same body burden of mercury.  The reason for this appears to be that the largest mercury carriers are also the largest fish that live longer than the others and are also higher up the aquatic environmental food chain than the others.  (We, of course, are even higher up the food chain, but don’t spend all day swimming.)

The ones that have the largest concentrations of mercury are then shark/flake, ray, swordfish, barramundi, gemfish, orange roughy, ling, and southern bluefin tuna.  Since tuna is one of the more popular types of canned fish available here in Thailand, is this then a problem?  Fortunately no, because the species used in canned tuna is a smaller one and generally the fish are only about one year old when caught for canning.

So what can pregnant ladies do, or even those contemplating pregnancy?  Can you get rid of the mercury by careful cooking of these types of high mercury bearing fish?  Unfortunately no.  No matter how you cook your fish (or shellfish) it does not change the levels.  The simple answer is that you should stick to the smaller fish species, even if bluefin tuna steaks are your kind of seafood.

And even though the absorption of mercury from the whitening creams is possible, the body burden of mercury from this is probably not very high at all, so caution is probably all that is needed.  And read the label.