ENVIRONMENTAL IMPACT OF MERCURY EMISSION FROM CHEMICAL PRODUCTION PROCESS- AND ITS REDUCTION.

Many public health experts, scientists and regulators view Mercury* across the nation as a significant environmental issue. Organic forms of this heavy metal, such as methyl mercury, are particularly toxic and of special concern because they can ‘ bioaccumulate’ or build up in concentration over time in living organisms, such as fish. Pregnant women who eat contaminated fish can pass mercury to their unborn children, who are very sensitive to its toxic effects Every day, chemically reactive mercury is released into the atmosphere by coal-fired power plants, cement manufacturers, incinerators, chloroalkali plants and a host of other sources and then deposited with rain or snow. This toxic heavy metal falls all around us, contaminating our rivers, lakes and streams. The rain is poisoning our fish and all the other species that rely on these basic ecosystems for survival. Mercury from rain can accumulate in our fish to levels that can poison wildlife and humans that eat them. It can fall hundreds of miles from its original source, contaminating pristine areas as far away as the North Pole—areas far from industrial pollution. Like PCBs, dioxins, and some other environmental contaminants, mercury can travel through the atmosphere and fall out with rain or snow. .Disposal of mercury-containing domestic batteries on dumps poses an enormous ecological problem; however this does help to put the dental use of mercury into perspective. It was estimated in the US in 1989 that discarded household batteries accounted for 86% of dumped mercury, while dental amalgam represented just 0.6% and has been declining steadily in quantity over the past three decades. Mercury compounds were once used extensively in the production of paper and Sweden was found to be dumping enormous quantities of mercury-rich effluent from its paper industry into the sea. Pressure from environmentalists has eradicated mercury use in paper-making for good. Bizarrely, there is also concern about the risk to health of mercury vapour discharged from crematoria as a result of incineration of people with amalgam fillings. Certainly, toxic mercury vapour is measurable in the the air downwind from crematoria when this occurs. There is international concern at present over the illegal dumping of thousands of tonnes of mercury every year, used for extraction of gold from ore, in the Brazilian Amazon area. Many hundreds of cases of mercury toxicity have been reported in the area and ecologists are very concerned about health effects once the water table is contaminated. More primitive gold extraction techniques involve boiling off mercury from gold-mercury amalgam in open pots over a fire. Mercury is universally detrimental to petroleum processing systems. In gas processing, mercury damages equipment and fouls cryogenic heat exchangers. In chemical manufacturing and refining, mercury poisons catalysts and contaminates waste water, thus impacting regulatory compliance. Maintenance workers in the petroleum industry can be at risk due to inhalation of mercury vapour and dermal absorption of organic mercury compounds unless proper precautions are implemented.