2.3.6 HEAVY-METAL INDUCED DISEASES
Following the Industrial Revolution, the production of heavy metals, such as
copper (Cu), lead (Pb), and zinc (Zn), has increased dramatically. Between
1850 and 1990, the production of these three metals rose nearly tenfold, with
concomitant increases in the emission of various metals including cadmium
(Cd), mercury (Hg), and nickel (Ni).
35 Another toxic element is arsenic (As).
Because of industrial pollution, some of these metals and nonmetallic elements
accumulate within limited geographic areas to excessive levels, which have
produced major outbreaks of chronic illness in humans. Some notable
examples of heavy-metal induced diseases and poisoning incidents follow.
Although chronic Pb poisoning has plagued humans since at least the time
of the ancient empires, the importance of Pb as an environmental pollutant has
received widespread attention only in recent decades. In ancient Rome, Pb in
pipes and in drinking and cooking vessels was a major source of excessive
intake. Even today, Pb contamination in water supplies occurs in some
communities. Lead pipes in older plumbing and soldered pipe joints can
contaminate drinking water, especially ‘‘soft’’ water. However, the Pb in smoke
from burning trash and coal and, until recently, automobile exhausts, is
probably even more hazardous as it is inhaled, or ingested as a contaminant of
foods (after settling on vegetation).
Lead-based paint in older homes is even more dangerous because small
children often ingest paint from woodwork, plaster, floors, and furniture. It is
not surprising, therefore, that as many as 25% to 30% of American children
living in urban areas may be suffering from ‘‘subclinical’’ Pb poisoning.
36 The
most prominent adverse effects of Pb involve the nervous system, the
hematopoietic system (the organic system of the body consisting of the
blood and the structures that function in its production), and the kidneys.
As mentioned previously, one of the most serious outbreaks of anthropogenic poisoning of the industrial age is the epidemic of Hg poisoning, now
known as ‘‘Minamata disease.’’ This illness occurred in Minamata Bay in
Kyushu, Japan, in 1953, and the highest incidence was found to be among
fishermen and their families.
37 Later, when it was observed that household cats
and sea birds were being affected, attention turned to fish and shellfish as
etiologic factors. This in turn led to the study of the water of Minamata Bay
and to the identification of Hg in a factory effluent as the cause of the disease.
The study concluded that fish that had been consumed by sufferers contained
high levels of toxic methylmercury (MeHg). When ingested, MeHg can induce
permanent damage to the brain and kidneys, loss of vision, and disturbed
cerebral function. Ultimately, coma and death follow in severe cases.
The discovery of gold (Au) in Serra Pelada in the Amazon in 1979 touched
off a great flow of migrants into that area in the 1980s. There are potentially
serious health effects from exposure to high levels of metallic Hg during mining
of Au. Hg is used to bind the Au, and the resultant amalgam is heated at high
temperatures with a blowtorch to separate Au from the Hg. This vaporized Hg
gradually accumulates in the aquatic food chain. In contrast to the Hg
Environmental Change and Health
27
[16:55 26/8/04 P:/CRC PRESS/4365 MING-HO.751 (1670)/4365-002.3d]
Ref: 4365 MING-HO YU Chap-002 Page: 27 13-30
Following the Industrial Revolution, the production of heavy metals, such as
copper (Cu), lead (Pb), and zinc (Zn), has increased dramatically. Between
1850 and 1990, the production of these three metals rose nearly tenfold, with
concomitant increases in the emission of various metals including cadmium
(Cd), mercury (Hg), and nickel (Ni).
35 Another toxic element is arsenic (As).
Because of industrial pollution, some of these metals and nonmetallic elements
accumulate within limited geographic areas to excessive levels, which have
produced major outbreaks of chronic illness in humans. Some notable
examples of heavy-metal induced diseases and poisoning incidents follow.
Although chronic Pb poisoning has plagued humans since at least the time
of the ancient empires, the importance of Pb as an environmental pollutant has
received widespread attention only in recent decades. In ancient Rome, Pb in
pipes and in drinking and cooking vessels was a major source of excessive
intake. Even today, Pb contamination in water supplies occurs in some
communities. Lead pipes in older plumbing and soldered pipe joints can
contaminate drinking water, especially ‘‘soft’’ water. However, the Pb in smoke
from burning trash and coal and, until recently, automobile exhausts, is
probably even more hazardous as it is inhaled, or ingested as a contaminant of
foods (after settling on vegetation).
Lead-based paint in older homes is even more dangerous because small
children often ingest paint from woodwork, plaster, floors, and furniture. It is
not surprising, therefore, that as many as 25% to 30% of American children
living in urban areas may be suffering from ‘‘subclinical’’ Pb poisoning.
36 The
most prominent adverse effects of Pb involve the nervous system, the
hematopoietic system (the organic system of the body consisting of the
blood and the structures that function in its production), and the kidneys.
As mentioned previously, one of the most serious outbreaks of anthropogenic poisoning of the industrial age is the epidemic of Hg poisoning, now
known as ‘‘Minamata disease.’’ This illness occurred in Minamata Bay in
Kyushu, Japan, in 1953, and the highest incidence was found to be among
fishermen and their families.
37 Later, when it was observed that household cats
and sea birds were being affected, attention turned to fish and shellfish as
etiologic factors. This in turn led to the study of the water of Minamata Bay
and to the identification of Hg in a factory effluent as the cause of the disease.
The study concluded that fish that had been consumed by sufferers contained
high levels of toxic methylmercury (MeHg). When ingested, MeHg can induce
permanent damage to the brain and kidneys, loss of vision, and disturbed
cerebral function. Ultimately, coma and death follow in severe cases.
The discovery of gold (Au) in Serra Pelada in the Amazon in 1979 touched
off a great flow of migrants into that area in the 1980s. There are potentially
serious health effects from exposure to high levels of metallic Hg during mining
of Au. Hg is used to bind the Au, and the resultant amalgam is heated at high
temperatures with a blowtorch to separate Au from the Hg. This vaporized Hg
gradually accumulates in the aquatic food chain. In contrast to the Hg
Environmental Change and Health
27
[16:55 26/8/04 P:/CRC PRESS/4365 MING-HO.751 (1670)/4365-002.3d]
Ref: 4365 MING-HO YU Chap-002 Page: 27 13-30