Chemistry Reference
In-Depth Information
primarily through contaminated food. Chronic occu-
pational cadmium poisoning was observed in the late
1940s in Sweden in the production of alkaline batteries.
It was shown that many of the symptoms were simi-
lar to what was seen in some areas of Japan and called
Itai-Itai disease, where inhabitants were eating rice
contaminated by cadmium from a river from a nearby
mining industry. Japanese and Swedish researchers
began long-term collaborative research projects. The
research clearly showed that exposure to cadmium was
a necessary factor for the development of Itai-Itai disease.
Chronic cadmium poisoning has now been observed
in several areas of the world, including Belgium, The
Netherlands, and China. In many more countries, increased
risks are seen as indicated by excessive concentrations in
certain foodstuffs (e.g., rice).
Cadmium is a good example of the need and value of
international collaboration. Questions relating to cadmium
poisoning have been on the agenda at several meetings
arranged by national and international bodies. IPCS pub-
lished a Health Criteria Document in 1992 (WHO/IPCS,
1992) based on several earlier drafts during the entire 1980s.
The Scientifi c Committee held a meeting in Bethesda,
Maryland, in 1978 and one in Shanghai, China, in 2003.
The last meeting focused on health impacts of cadmium
in China and its prevention (Nordberg
et al.,
2004b).
I hope this has given some information on the need
to have international perspectives when evaluating and
preventing health effects of metals. The responsibility
for this is partly up to governments and international
and national organizations. The Scientifi c Commit-
tee has an important role as an organization with high
competence and with no formal strings to governments,
communities, or industries. It is important that in the
future IPCS also gives a high priority to metal toxicity.
It is important to disseminate information on metals
and their occurrence and toxicity not only to active sci-
entists and administrators but also to local doctors and
engineers. Here the concept of a Handbook is extremely
important. The earlier editions of the
Handbook on
the Toxicology of Metals
have served this purpose. We
expect that the third edition will continue to have such
a tutorial task. A Handbook also gives the easiest access
to the entire spectrum of metal toxicology.
research. This section of the chapter will summarize a
number of cross-cutting research areas for metals that
are discussed in much greater detail in subsequent
individual chapters.
2.1 Expanding Current Industrial New
Technological Uses of Metals
The toxicology of metals is concerned with some
80 elements and related species, ranging from com-
paratively simple ionic salts to complicated structures,
such as complexes consisting of a metal atom and a set
of ligands and organometallic compounds. Pollution
of the environment and human exposure to metallic
elements may occur naturally, for example, by erosion
of surface deposits of metal minerals, as well as from
human activities, such as mining, smelting, fossil fuel
combustion, and industrial application of metals. The
modern chemical industry is based largely on cata-
lysts, many of which are metals or metal compounds.
Production of plastics, such as polyvinyl chloride,
involves the use of metal compounds, particularly
as heat stabilizers. Plating and the manufacture of
lubricants are still other examples of industrial uses of
metals. The industrial and commercial uses of metals
are continuously increasing. In the development of
advanced technology materials, new applications have
been found for the most familiar and for the somewhat
less familiar metallic elements. Most notable are their
uses in the development and production of semicon-
ductors, superconductors, metallic glasses, magnetic
alloys, high-strength, low-alloy steel, and most recently
in nanotechnology (IARC, 2006).
Some of the new uses like nanotechnology have
the potential of causing direct exposure of humans.
Many other uses, and also discharges from nonmetal-
producing activities such as electricity production
from coal combustion, may increase both the amount
of and the distance over which metals are discharged
into the human environment. The distance from source
of emissions of metals to their sinks can sometimes be
more than 1000 km for airborne transport. When met-
als are transported along aquatic and terrestrial routes,
they often enter into the food chain. Furthermore, the
use and disposition of the new technological equip-
ment increase E-waste. If not recycled in appropriate
waste-handling systems, metals/metalloids used in
semiconductors will enter the ecological pathways.
2 CURRENT CONCERNS RELATED
T
O THE TOXICOLOGY OF METALS
In addition to the considerations in the fi rst part of
this chapter, including the need for international joint
action to control identifi ed risks from exposures to
metals in humans, the following considerations are of
importance with regard to current and future areas of
2.2 Ecological and Natural Environmental
Mobilization Processes
The acidifi cation of soil and lakes by sulfur and
nitrogen oxides has increased the possibility for adverse
