|Pollution May Cause 40 Percent of Global
By Andrea Thompson
September 10, 2007
In Dzerzhinsk, Russia, waste from 190 chemicals has turned the groundwater
into a dangerous toxic sludge. Life expectancy there is 42 for men and 47 for
women. Credit: Blacksmith Institute Water, air and soil pollution, along with
other environmental factors, contribute to 40 percent of deaths worldwide each
year, a new study concludes.
In a review of research into the effects of environmental pollutants and other
sources of environmental degradation, Cornell University ecologist David
Pimentel estimates that 62 million deaths per year (40 percent of all that
occur) can be attributed to environmental factors, particularly organic and
chemical pollutants that accumulate in the air we breathe and the water we
Though scientists and organizations such as the United Nations and the World
Health Organization have begun keeping tabs on the role environmental pollution
plays and were aware of the enormous impact that some pollutants have, "we were
surprised with the number," Pimentel said.
This "suggests the importance of the environment as it's related to our deaths,"
he told LiveScience.
With an estimated 1.1 billion people in the world lacking access to clean water
(according to WHO estimates), it is little wonder that waterborne infections
account for 80 percent of all infectious diseases in the world.
"Water is one of the major concerns, without any question," Pimentel said,
because everyone must use it for drinking, cooking, washing and bathing.
Water contaminated with untreated sewage and fecal matter can facilitate the
transmission of diarrheal diseases such as cholera (bacteria that live in
feces), intestinal infections (which can compound health issues by causing
malnutrition) and other diseases—all of which kill millions every year,
A 2004 study by the Population Resource Center found that 2.2 million infants
and children die each year from diarrhea, caused largely by contaminated water
and food. And, according to their estimates, polluted water in Africa and India
causes 1.4 million deaths each year as a result of diarrheal diseases such as
cholera and dysentery.
"Water sanitation and hygiene are, considered globally, one of the big, big
causes of disease," said WHO scientist Annette Prüss-Üstün.
Most of the problems from contaminated water are an issue in developing
countries, where there is little infrastructure to deal with sewage and other
water sanitation issues—people in developing countries dump 95 percent of their
untreated urban sewage into the same lakes and rivers they use for drinking and
bathing, according to the United Nations.
"While in many countries there is still [a] water supply, proper disposal and
treatment of sewage is a little bit less common in developing countries,"
In India, for example, only a handful of cities have water treatment facilities,
according to Pimentel.
"It's a challenge just to get clean water," he said.
Air pollution is another big killer. The WHO ranks it as the eighth most
important risk in the burden of disease and deems it responsible for 3 million
deaths each year through diseases such as pneumonia, chronic bronchitis and lung
In developing countries, indoor air pollution is a major problem because most
people rely on open stoves fueled by dung, wood, crop waste or coal to cook and
heat poorly-ventilated homes.
A little more than half of the world's households use these solid fuels for
cooking, "which is huge," Prüss-Üstün said. The smoke from these stoves
accumulates in abodes, exposing those inside—mainly women and children—to the
hazardous pollutants released from the fuel.
"In some houses you enter into the kitchen, and even though you might even have
a permanent opening in the house ... you can hardly see ... the wall on the
other side, so thick is the smoke," Prüss-Üstün said.
More than 200 different chemicals can be found in the smoke, and 14 of them are
known carcinogens, Pimentel said. Every year, this indoor air pollution kills
1.6 million people (or one person every 20 seconds), according to the WHO.
Outdoor air pollution, on the other hand, accounts for some 800,000 deaths per
year—about half as many as for indoor air—because the pollutants are much less
"Indoor air pollution can be 100 times more concentrated," Prüss-Üstün said.
"There's really a big difference."
But outdoor air pollution still impacts health—both in developing countries and
cities in the developed world—through chronic respiratory problems, acute
problems (such as asthma) in children and "a long list of cardiopulmonary
diseases in adults," Prüss-Üstün said.
And as the world's population continues to grow and shifts to urban areas,
outdoor air pollution will become a more serious health threat, Pimentel added.
Health is also affected by the tens of thousands of chemicals put into the
environment by industrial processes and other sources.
With most of these chemicals, the environmental and biological effects they may
have, including their toxicity to humans, is largely unknown, particularly
because so many are used in combination.
"It's impossible to estimate," Prüss-Üstün said. "It's truly impossible to
estimate more precisely, because ... there are so many toxins."
But according to studies cited in Pimentel's review, detailed in a recent issue
of the journal Human Ecology, chemical exposures can contribute to cancers,
birth defects, immune system defects, behavioral problems, altered sex hormones
and dysfunctions in specific organs.
Americans of all ages carry at least 116 foreign chemicals in their bodies,
according to Pimentel's review, including the pesticide DDT (which still
persists though it was banned three decades ago in the United States), lead and
mercury (with coal-powered plants being the largest source of mercury
The uncertainty in some of these connections has led to lower, more conservative
estimates of the part that environmental pollution plays in the global burden of
disease. WHO estimates have linked only 25 percent of the global disease burden
to pollution, because they have included only the more firmly known links,
But what is clear, both Prüss-Üstün and Pimentel say, is that a large number of
deaths could be prevented if developing countries were educated on and helped
with the problems posed by water and indoor air pollution, which while fairly
easy to solve in the developed world are beyond the means of those affected in
developing countries to fix on their own.