Pollution in the far east is a widespread problem. Even the most fundamental environmental controls are ignored in favor of profit. Japan's use of mercury and its dumping was captured by an American Photographer about 50 years ago (sorry do not remember his name). The photographs were some of the most heart wrenching I have ever seen. The factories were dumping mercury compounds into the bay, the fish ate the contaminated food, the people ate the fish. The number of birth defects were enormous. While taking the photographs, he was beaten multiple times, injuries from the beatings eventually contribute to his untimely death. The resulting book caused such a loss of face for the Japanese people, they "cleaned up" the bay. I put the word cleaned up in quotes because there a many learned scientific articles which say that decades are required for the elimination of mercury. The current method for cleaning heavy metal contamination is to scoop up the dirt, double seal it in high density polyethylene barrels and hope that future generations will develop a method of cleaning the contaminated material.
Metallic mercury by itself is considered fairly harmless, however, it does have a significant vapor pressure. Mercury vapors are highly toxic and cause many illnesses.
Mercury compounds, especially organo-mercury, are deadly!
Also, while reading this thread, I saw mention of radioactive compounds. The only way to cleanup radioactives is to collect them and any material they have contacted, put it in a lead lined barrel and wait ten half-lives (one half-life is the time for the radioactivity to decrease by 50%). For example, Cobalt-60 has a half-life of 5.3 year, if you house is contaminated with Co-60, it will be 53 year before you can go into you house without being exposed to gamma radiation.
Sorry about climbing on a soap box, but the mindless dumping of waste really get to me.
Wayne Nunn. Ph.D, Chemistry
Virginia Tech, Class of '78