In the 1865 children's story Alice in Wonderland the Mad Hatter is a hat maker who wears a tophat, speaks gibberish and moves in an odd way. We now know that the Mad Hatter was not just a fictional character.

Because the fashionable nineteenth-century top per required the use of mercury for stiffening its felt so it would stand up straight, factory workers would come into frequent contact with the metal. They would often suffer from a damaged central nervous system, loss of speech control, impaired vision and the ability to move. These hatters were not suffering from any disease; they had been poisoned by mercury.

Lin Cheng-fang, an associate professor of environmental engineering at Taiwan University, explains that "heavy metals" is no more than the name used by chemists for those metals in the periodic table that are comparatively heavy. It is especially applied to such metals that are used most frequently in modern industrial manufacturing, such as nickel, chrome, copper, zinc, lead, cadmium, mercury and arsenic.

Mysterious and unlucky: Heavy metals in the state of nature are found stored in mineral ores. In the history of man's development from Stone Age to Chemical Age, these elements have always played an important role: Copper helped mankind to create the civilization of the Bronze Age and as early as three thousand years ago the ancient Egyptians knew how to smelt lead to make the tools of everyday life.

The medicines and cosmetics of China's ancient ancestors also often contain small traces of heavy metals. For example, cinnabar, which was used as a sedative, contained a portion of mercury, while small amounts of arsenic could lighten the skin. Copper and zinc, used to control hair loss, are also trace elements that the human body cannot do without and which will certainly be contained in the daily vitamin pills that are so fashionable today.

Yet the chemistry of the heavy metals is particularly complex and they have certainly played more than just an orthodox role in human society. The mercury that drove the Hatter mad was actually seen as a mysterious and inauspicious substance by medieval alchemists in the West and people would often use it to commit suicide. People thus came to suspiciously revile it, and Napoleon on his island exile of Elba is probably its most well-known victim.

Before Taiwan's economy really took to the skies, housewives had little opportunity to use famous brandname cosmetics. Many of them thus took to using low-quality face powder which contained amounts of lead that precipitated in their skin to leave black blemishes that cannot be removed. Then there was the outbreak of a disease that left people with blackened feet in the coastal area of southern Chiayi which has been proved by experts on contagious diseases to have been related to the protracted use of underground water containing too much arsenic for drinking.

"Whether heavy metals are toxic or not is related to the amount and length of time with which people come into contact with them," says Li Chunfu, associate professor of the graduate school of environmental engineering at the National Central University. Most of the heavy metals are certainly not elements that the human body must have but they are also not like pesticides and various organic substances that can bring about rapid poisoning. They often need a long time to accumulate before resulting in illness, but the style of modern living creates just the right conditions for large concentrations to build up in the human body.

Humanity's helping hands? As well as there having been constant advances in mining and the extraction of ores, mankind's exploitation of heavy metals has increased without let as chemical industries have used our rich knowledge of chemistry to create techniques and develop their all-round potentials. Take lead, for example: Apart from lead the metal, there are also lead alloys, and more than a hundred inorganic and organic lead compounds. It is this rapidly increasing number of heavy metal compounds and alloys that are incessantly making their way into the sphere of modern living.

In 1924, lead compounds were added to gasoline so as to increase the efficiency of cars. In that "Kingdom of the Automobile," the United States, within 40 years the amount of lead used in this way increased from 400 tons a year to 280,000 tons. There have also been incidents of birds laying eggs with brittle shells and of infertility that have been put down to the use of insecticides containing mercury compounds made from combining the toxic metal with organic substances.

The soft spot modern people tend to have for carrying leather handbags and wearing leather shoes also means that leather factories have to use chrome and its compounds to tan hides, making them pliable and easy to cut. Then there is the bustle of commercial society in which large numbers of people rush between the airports of different countries, requiring yet more chrome to be used to make aircraft components capable of resisting corrosion and withstanding strong winds and driving rain.

Heavy metals and their compounds are also important elements in electroplating: The zippers on clothing, shiny belt buckles and elegant men's cufflinks, along with all kinds of household appliances and computer components are electroplated using zinc, nickel, chrome and other elements so that they become durable and attractive. To take the United States as an example, US$3 billion must be spent every year because metal implements are liable to corrosion from acid rain penetration--and the uses of electroplating are growing all the time.

Then there is the much overlooked area of agriculture in which many fertilizers and pesticides contain heavy metals. Taiwan's pig farmers, for example, bring about increases in "productivity" by making pigs grow quicker and larger through the addition of zinc and copper to their feed.

Changing nature leads to increased toxicity: Heavy metals tend to be seen by people as helping hands. However, originally stored safely in the earth, when constantly disturbed by being dug out they form into natural combinations with other elements to create compounds such as oxides, or get chemically rearranged by human action into new formations. Having had their "customs" changed, their characters also change and many highly toxic substances appear.

"Whether or not heavy metals are poisonous also depends on how they are stored," says Lin Cheng-fang, taking chrome as an example. One of the compounds in which this metal appears is seen as one of the most fearsome of lethal toxins by chemists. However, "in its natural environment chrome only appears in minuscule amounts," Lin adds.

As for mercury, making up no more than 0.03 percent of the earth, it was originally a very rare element, taking sixteenth place from the bottom among all the elements. Due to its being used by physical and biological forces, it is found in the earth, rivers, air and sea but not concentrated in any one environment. From the state of nature it takes extremely sensitive methods to detect the pure metal.

According to statistics in the report Environment and Society published in the 1970s in the United States, the standard of living of Americans needed to no more than double since the second world war for the amount of mercury used to produce chlorides, oxides and hydrogenates to increase 40 times. Every year broken thermometers alone account for some 7,000 kilograms of mercury escaping into the environment. And mercury is not the only example: Today the amount of lead in the atmosphere has increased more than 100-fold.

The natural distribution of heavy metals has been disturbed and they have been dispersed from their originally secure ecological position. In the course of life and industrial production people lack any real sense of alarm about all this. With the failure to take precautions the situation has gradually become harder to contain. Heavy metals have thus become a new subject of study in medicine--a kind of pathfinder in "environmental medicine."

Modern Mad Hatters: In the past, contact with heavy metals was restricted to professional workers and those who often came into contact with the source of the pollution. The Mad Hatter can thus be said to be a precursor of more recent victims of industrial sickness from heavy metals. Up until today, the nonchalant attitude of industrialists has led to an inflaming of the situation of industrial ailments.

Three years ago, the Keelung Hsingyeh Motor Company was producing lead batteries for motorcycles. The workers were not separated from the lead dust in their working environment and "did not even wear masks over their mouths," according to a professor at Taiwan University's department of public hygiene who was commissioned to deal with cases of lead poisoning in industrial workers.

Hsingyeh was also carelessly dumping lead into the land outside the factory which was having an effect on children who played there. An investigation undertaken by Taiwan University's department of public health discovered that the number of children with learning disabilities in the area was well above the ratio in other places.

Such time bombs are not only ticking away waiting to explode in individual factories. Pollutants also use the bodies of products and the air and soil as mediums. Direct and indirect contacts are a risk to people's health. The lead pumped out in car exhausts, for example, goes straight into the atmosphere. Statistics show that 250,000 children suffer from lead poisoning each year in the United States alone, which produces varying conditions of damage to the central nervous system.

At the turn of the century people had already started to record the amount of mercury found in fish and discovered a constant increase. Then, in 1953, at Japan's Minimata Bay, there erupted a very serious incident of mercury poisoning: A factory near the bay, in the process of making acetaldehyde had used mercuric oxide as a catalyst and then proceeded to dump it straight into the bay. Hoping that it would be dispersed into the ocean, they had not realized that mercury compounds would drift back into the shallows and get into the food chain to end up concentrated in living organisms--little fish eat shrimps and big fish eat little fish until the mercury in the shrimps and little fish ends up accumulated in the big fish. A recent American investigation actually found that the body of a fish can build up four to five hundred times the level of mercury that exists in the water it swims in.

Mercuric fish and green oysters! When the inhabitants of Minimata Bay ate the mercury contaminated fish their muscles wasted away, they lost their sight, and became psychologically damaged. Brain damaged and finally paralyzed, many fell unconscious and nearly 150 of them died. In 1967, there were some 20 cases of food poisoning in the Japanese city of Nigata due to the same reason. At the beginning of the 1980s, more cities also began to show up cases of mercury poisoning caused by seafood bought from shops.

The same kind of thing also happens frequently in Taiwan. Seven years ago in Tainan's Wanli, industrialists dumped copper waste from an acid washing process into the Erhjen River, resulting in pollution of the pisciculture in its lower reaches. Consumers who ate the river's "green oysters" became very sick and "live seafood" became synonymous with "poison."

The water we drink, the food we eat and the air we breathe are all full of heavy metals and their compounds and it seems that the amounts in which they exist in our living environment are getting higher and higher. There is no way to escape and our bodies now show up traces of elements that they just do not need.

Today we have ten times as much lead in our blood as did our forebears of a century ago and a 1964 survey carried out at the World Games in Tokyo to measure the amount of mercury in the hair of participants discovered they had at least twenty times what was previously recorded. In 1964 the American writer Rachel Carson, in her book Silent Spring, described how "destructive chemical products stay in the soil, get into the green grass or the fields planted with rice and wheat, spread with the days and accumulate with the months, getting into peoples bones and staying with them right up until they die."

Get the lead out: Apart from the powerful toxins produced comparatively easily by factories, just what is the danger level for heavy metals in the human body? There is still no way to be sure. However, ailments such as cadmium, lead and mercury induced damage to the central nervous system, sterility and deformities, impairment of the immune system, damage to the respiratory system, liver poisoning and irreversible chronic poisoning are all on the rise. In relation to the chemical substances that are increasingly coming to permeate our daily lives, people are gradually coming to realize the risks they face from heavy metals.

Lead water pipes are already being discarded by all countries; manufacture of the lethal first generation of pesticides which contained organic mercury compounds has already been forbidden; and the United States Food and Drug Administration has decreed a ban on using cadmium electroplated containers, because they can cause acute poisoning if used for any kind of acidic food or drink.

What is contradictory is that, on the one hand, people are careful to take precautions, while, on the other, new metal compounds are still being developed. This is partly because metals that can only be mined in very small quantities and are not widely used tend not to come to the attention of the public. An example is the use of titanium for aeronautical components, which has been proved to lead to poisoning of the lungs.

Six years ago, the American company, Du Pont, wanted to establish a titanium dioxidizing factory in Lukang's Changpin industrial park but decided to suspend its plan on running into local opposition. Titanium and its eighteen compounds "are not only acutely poisonous to the lungs but can also cause burns and other types of chronic poisoning," points out Professor Wang Jung-te of Taiwan University's department of public health in his book Pollution and Disease. Professor Chen Zuengsang of Taiwan University's Department of Agricultural chemistry adds that, "If you use little and understand little, this does not represent that something is not a pollutant." There are still many hidden properties of metal compounds that destroy the environment.

Aluminium and Alzheimer's? As a matter of fact, the spread of the use of chemical elements is not confined to the heavy metals. The other chemicals of the periodic table are also being used very widely, but due to the agency of natural microorganisms and their combination with organic substances they get broken down. Basically it is only the heavy metals that cannot merge into nature but leave traces that last for a very long time.

In the history of pollution-related diseases, although other metals are not like the family of heavy metals, they still have the potential to slowly accumulate. It is just that if you look at metals such as gold and iron, the former is extremely rare and inert and cannot easily undergo chemical changes through combining with other materials, while the latter is used in huge quantities but is actually needed by the human body -- medics even recommend that we use iron cooking pots so as to provide us with supplementary iron.

But doctors warn us to cut down on our use of aluminium pots and pans because when food is cooked in them it can combine with the aluminium to create a compound which can lead to Alzheimer's disease, irregular movement, loss of memory, loss of motor coordination and other problems of the brain. A British report has pointed out that cooks who use aluminium utensils often end up with problems of digestion, stomach troubles, hernias and headaches.

Small quantity--much pollution: The environmental damage caused by heavy metals and their compounds can still be minimized by careful handling. For example, factories can choose the relatively more expensive but less polluting metal, cadmium, to replace the more toxic compounds most commonly used by plastics manufacturers at present.

As for those heavy metals that have already made it into the environment, people have no way to really terminate them. Yet why is it that these metals that were taken from nature in the first place cannot return there?

Lin Cheng-fang provides an illustration: A door made of copper cannot harm people, but if it comes into contact with a wet acidic body you will see a solution which gradually turns blue. This is a copper isotope seeping out of the piece of metal. Although the quantity of this isotope is extremely small and will not really have any effect on the mass of the door, if one liter of water contains five milligrams of it, which is just a few billionths of the volume, that is a very serious case of pollution. It is these minuscule amounts that cause environmental problems. Because of this, up until today, there is no technology that can "recycle" and prevent such pollution from heavy metals. The only alternative is to minimize wastage, such as by cutting out the use of leaded gasoline. No matter whether in East or West, the management of heavy metal waste today can usually only be carried out by precipitating out pollutants, mixing them with concrete and then finding a place to bury them.

What age do we live in? Today archaeologists are discovering through their excavations the roads taken by past civilizations. They have arrived at the Stone Age, Bronze Age and Iron Age. But what will the archaeologists of the future make of our "civilization?" As they dig out lump after lump of contaminated concrete, perhaps they will ask: "What should we call this age?"

[Picture Caption]

Heavy metals can be beneficial to life; alkaline batteries are one example. But when too much is used, or they are poorly handled, they can become environmental killers.(photo by Pu Hua-chih)

Brother, you should maintain your bike. All of us are unwittingly suffering lead pollution from cars and motorcycles.

Shiny or reflective home appliances usually go through electroplating.

Leather goods require chemical treatment to soften them for cutting. Take a look--how many pairs of shoes in your closet? How does the figure compare to the number laid out by this street vendor? (Sinorama file photo)

Much of the waste material from rural society can be reabsorbed into the natural cycle. What kind of garbage will today's society leave for future generations?

Brother, you should maintain your bike. All of us are unwittingly suffering lead pollution from cars and motorcycles.

Shiny or reflective home appliances usually go through electroplating.

Leather goods require chemical treatment to soften them for cutting. Take a look--how many pairs of shoes in your closet? How does the figure compare to the number laid out by this street vendor? （Sinorama file photo）

Much of the waste material from rural society can be reabsorbed into the natural cycle. What kind of garbage will today's society leave for future generations?