for human health. In particular, persistent organic pollutants (POPs) and
heavy metals impact on human health, and as such are two groups of hazardous
chemicals that have received special attention in recent years.
POPs are of particular concern as they have four common properties: high
toxicity, persistence, a special affinity for fat, and high mobility. POPs comprise
semi-volatile compounds, which may occur in solid, liquid or gaseous form,
depending on the temperature. They have a propensity to evaporate and travel
long distances (often thousands of miles in air, water currents, and through the
food web; so much so that they are of global concern), and become more
concentrated higher in the food chain and with time. As POPs have an affinity for
fat, there are major intergenerational human health concerns, as the chemicals
can be passed from mother to child during breastfeeding. This transmission can
disrupt development of the child and lead to long-term damage. Whilst the effects
of POPs on human health are unclear, the weight of evidence suggests that high
levels of long-term exposure may lead to birth defects, infertility, increased
susceptibility to disease, diminished IQ and an increase in cancers.
The high mobility of POPs can be seen in the evidence from the Arctic Region.
In the 1950s a thick haze observed in the North American Arctic was traced to
sulfates and dust particles that originated in lower latitudes. This long-range
mobility is an example of regional environmental change involving ‘transboundary
pollution’. In 1972 the Stockholm Declaration on the Human Environment
declared that states have a responsibility ‘to ensure that activities within their
jurisdiction or control do not damage the environment of other states’, and this
became the foundation for establishing the Long-Range Transboundary Air
Pollution (LRTAP) regime.
The bioaccumulation of these chemicals occurs when organisms at the base of
terrestrial and marine food chains — for example lichen or phytoplankton —
absorb the pollutants. These then work their way through the food chain and are
eventually consumed by the local human population. The affinity for fat that is
displayed by POPs is of particular concern for the populations of these more
northern regions, particularly as the same fat which allows them to survive the
temperatures at these latitudes is also a store for these pollutants. The United
Nations Environment Program (UNEP) responded to international concerns
over these persistent chemicals and mounted a campaign for an international
ban. This campaign has focused on the twelve most dangerous chemicals — the
so-called ‘dirty dozen’ (see Table 1) — and the UNEP has recently drafted a treaty
to ban the production and use of these chemicals.
Heavy metals (for example, mercury, lead and gold) are also of great concern
for human health, and have been involved in numerous health disasters. A classic
example is the case of Minamata disease. In 1956, hundreds of people in the
Japanese coastal town of Minamata were seriously affected by methylmercury
United Nations Environment Program, Global Environment Outlook 2000, Earthscan, London,
1999.
World Wildlife Fund, Issue Brief — Persistent Organic Pollutants: Hand-me-down Poisons that
Threaten Wildlife and People, World Wildlife Fund:
http://www.worldwildlife.org/toxics/progareas/pop/pop.pdf, Washington DC, 1999.
O. R. Young, Environment, 1999, 41, 20.
D. J. Tenenbaum, Environ. Health Perspect., 1998, 106, A64.
Global Environmental Changes and Human Health
145
heavy metals impact on human health, and as such are two groups of hazardous
chemicals that have received special attention in recent years.
POPs are of particular concern as they have four common properties: high
toxicity, persistence, a special affinity for fat, and high mobility. POPs comprise
semi-volatile compounds, which may occur in solid, liquid or gaseous form,
depending on the temperature. They have a propensity to evaporate and travel
long distances (often thousands of miles in air, water currents, and through the
food web; so much so that they are of global concern), and become more
concentrated higher in the food chain and with time. As POPs have an affinity for
fat, there are major intergenerational human health concerns, as the chemicals
can be passed from mother to child during breastfeeding. This transmission can
disrupt development of the child and lead to long-term damage. Whilst the effects
of POPs on human health are unclear, the weight of evidence suggests that high
levels of long-term exposure may lead to birth defects, infertility, increased
susceptibility to disease, diminished IQ and an increase in cancers.
The high mobility of POPs can be seen in the evidence from the Arctic Region.
In the 1950s a thick haze observed in the North American Arctic was traced to
sulfates and dust particles that originated in lower latitudes. This long-range
mobility is an example of regional environmental change involving ‘transboundary
pollution’. In 1972 the Stockholm Declaration on the Human Environment
declared that states have a responsibility ‘to ensure that activities within their
jurisdiction or control do not damage the environment of other states’, and this
became the foundation for establishing the Long-Range Transboundary Air
Pollution (LRTAP) regime.
The bioaccumulation of these chemicals occurs when organisms at the base of
terrestrial and marine food chains — for example lichen or phytoplankton —
absorb the pollutants. These then work their way through the food chain and are
eventually consumed by the local human population. The affinity for fat that is
displayed by POPs is of particular concern for the populations of these more
northern regions, particularly as the same fat which allows them to survive the
temperatures at these latitudes is also a store for these pollutants. The United
Nations Environment Program (UNEP) responded to international concerns
over these persistent chemicals and mounted a campaign for an international
ban. This campaign has focused on the twelve most dangerous chemicals — the
so-called ‘dirty dozen’ (see Table 1) — and the UNEP has recently drafted a treaty
to ban the production and use of these chemicals.
Heavy metals (for example, mercury, lead and gold) are also of great concern
for human health, and have been involved in numerous health disasters. A classic
example is the case of Minamata disease. In 1956, hundreds of people in the
Japanese coastal town of Minamata were seriously affected by methylmercury
United Nations Environment Program, Global Environment Outlook 2000, Earthscan, London,
1999.
World Wildlife Fund, Issue Brief — Persistent Organic Pollutants: Hand-me-down Poisons that
Threaten Wildlife and People, World Wildlife Fund:
http://www.worldwildlife.org/toxics/progareas/pop/pop.pdf, Washington DC, 1999.
O. R. Young, Environment, 1999, 41, 20.
D. J. Tenenbaum, Environ. Health Perspect., 1998, 106, A64.
Global Environmental Changes and Human Health
145