Mercury is not outlawed. Thimerosol is still widely used a preservative in vaccines and mercury amalgam is what is normally used to fill your cavities.
To make this fishing related it has been found that high mercury levels in some fish is actually a naturally occurring phenomena, not a pollution issue. Samples of Swordfish caught early last century were tested and contained very high mercury content. Because they are long lived predators they tend to concentrate mercury (among other things) over their entire lifetime. Interesting
This is called bio-accumulation and although it is a process of the natural world, when it comes to mercury, it is not a natural occurring phenomena in the sense that it would happen no matter what....... the introduction of high concentrations of heavy metals to the lower end of the food chain is a very unnatural act.... it is the deadly curse that makes the presence of heavy metals in the environment a threat to life.....
these compounds are stored in fatty tissue of animals in the food chain , but are not able to be eliminated........ a swordfish retains all the mercury present in every little fish he ever consumed..... accumulating............. accumulating,............ accumulating............... problem is, the mercury should never have been in the food base to begin with.
this is what brought Bald eagle and many predatory birds to the edge of extinction.... ddt and pcbs accumulated in these animals from the top of the food chain to such levels as to frigg up the reproduction processes....
these birds where only able to recover after the source contaminant was removed from the environment.
Another bit...... because mammals feed their young milk, and milk is a fatty agent , these heavy metals that are bio accumulated are passed on directly to the offspring, and begin to bio accumulate within them...
Splinta
