Living in a city and caught up in the cross-currents of our
daily living dilemmas and demands, we barely notice the pollution that is there
all around us, inside us, sometimes in deafening forms, but mostly in a surreptitious
manner. If truth be told, pollution, which is clearly one of the leading
contributing factors to death and disability in the world, has gained a good
degree of acceptance among us city dwellers. We tolerate it far more than
should be the case. Sometimes, when we find it staring us in the face, we give
it a curious glance (oh, you are here to stay, are you?), acknowledge its
presence with a sideways nod (suit yourself, will you?), and move on with
whatever it is that we have to do to make the ball of living rolling.

So, most of us know that urban air pollution not only exists
but also thrives. How about car battery recycling, though? And contaminated
surface water and groundwater? Do we suspect that metal processing smelters or
facilities can have negative fallout on what we consume as food?

A report titled ‘World’s Worst Pollution Problems’, work on
which was undertaken by New York-based Blacksmith Institute and Green Cross
Switzerland, identifies six toxic pollutants that impact the health of tens of
millions of people, primarily children. The six pollutants in order of the
impact they have are lead, mercury, chromium, arsenic, pesticides, and

The focus on specific pollutants reflects a more
sophisticated understanding of the scope of toxic pollution globally. The 2010
report provides evidence of the scope of pollution and the global distribution
of each pollutant, as these toxic substances originate from a number of
different sources. Lead, the world’s worst toxic threat, comes from leaded
gasoline for transportation, metal smelters, battery recycling, sinker
production for fishing, colour and ceramics manufacturing, and lead mats for
radiation protection. Due to its many different sources, lead is a health risk
for people on every continent.

Read ahead and learn more about the world’s worst pollution

Groundwater contamination

Groundwater is rainwater or water from surface water bodies,
like lakes or streams, which soaks into the soil and bedrock and is stored
underground in the tiny spaces between rocks and particles of soil. Groundwater
is almost 97 per cent of the world’s accessible freshwater resource. About two
billion urban and rural people depend on groundwater for everyday needs.

Groundwater pollution occurs when hazardous substances come
into contact with the water that has soaked into the soil. Groundwater can be
polluted by municipal, industrial, agricultural, and individual sources.
Municipal sources of groundwater contamination include open dumpsites, poorly
constructed landfills, latrines, and other waste sites. Industrial pollution
can emanate from dumping of wastewater or waste, from untreated effluents, from
mining activities, and from leakage or spillage from other industrial

Wastewater disposal practices of certain types of businesses,
such as automobile service stations, dry cleaners, electrical component or
machine manufacturers, and metal platters or fabricators are particularly
suspect because the waste they generate is likely to contain toxic chemicals.
Other industrial sources of contamination include cleaning off holding tanks or
spraying equipment on the open ground and storing hazardous materials in
uncovered areas or in areas that do not have pads with catchment basins. Mining
of fuel and non-fuel minerals can create many channels for groundwater
contamination through the mining process itself, disposal of wastes, and
processing of the ores and the wastes it creates.

Agricultural contamination is primarily due to spillage of
fertilizers and pesticides during handling; runoff from the loading and washing
of pesticide sprayers or other application equipment; using chemicals uphill
from or within a few hundred feet of a well; storage of agricultural chemicals
near conduits to groundwater, such as open and abandoned wells, and sink holes;
and chemicals stored in uncovered areas or in locations where the groundwater
flows from the direction of the chemical storage to the well.

Individuals pollute groundwater by improperly disposing of
household chemicals such as paints, synthetic detergents, solvents, oils,
medicines, disinfectants, pesticides, batteries, and motor oil.

Industrial mining activities

The report ‘World’s Worst Pollution Problems’ uses industrial
mining activities to include mines that are currently engaged in mineral and
metal extraction operations. The materials can range from common to precious
and from inert to hazardous. Mining for precious metals, coal, and other
commodities forms an important part of many countries’ economies. Developing
countries such as Brazil, China, India, and Peru contribute a large proportion
of the world’s mining products. For example, of the total world production of
iron ore (1,020,000 metric tons), 21% is produced by China, 19% by Brazil, and
7% by India (USA National Mining Association 2002).

The most common pollution problem for an active mine arises
from the disposal of mineral wastes, mainly mine waste rock and tailings.
Economic ore deposits contain many chemical elements in addition to those that
are extracted for sale. Some of these are toxic and they are often present at
concentrations that pose risks to the environment and human health. They can be
leached from both sources, transported by wind, or taken up by plants and
animals in the human food chain. Physical agents such as asbestos and
crystalline silica can also be windborne, and radioactive minerals pose their
own set of risks. Substances emitted from or present at mine sites can enter
the body in a variety of ways such as inhalation, absorption through dermal
contact, or ingestion of contaminated food and water.

Metal smelters and processing

Metal processing smelters or facilities extract metals from
ore to create more refined metal products such as copper, nickel, lead, zinc,
silver, cobalt, gold, and cadmium. Smelting specifically involves heating the
ore with a reducing agent such as coke, charcoal, or other purifying agents.

Emissions of high quantities of air pollutants such as
hydrogen fluoride, sulphur dioxide, oxides of nitrogen, offensive and noxious
smoke fumes, vapours, gases, and other toxins can be found near facilities that
carry out metal and smelting processes.A variety of heavy metals like lead, arsenic, chromium, cadmium, nickel,
copper, and zinc are also released by the facilities.

Inhalation of pollutants occurs as a consequence of gaseous
emissions and fine dust or particulate matter (pm). Metal-bearing dust
particles can travel distances to pollute the soil and surface waterways.
Layers of dust can settle on to nearby agricultural fields, causing crop intake
of pollutants and later consumed by humans. Particulate matter emissions,
sewage waters, and solid wastes also enter waterways used for drinking water.

Radioactive waste and uranium mines
As explained in the report ‘World’s Worst Pollution
Problems’, radioactive materials are used for power generation, military
purposes, treatment and analyses in the medical sector, material control and
treatment in industry, products of daily life, and scientific applications.
Radioactivity is the sign that matter is decaying in order to reach, according
to the law of physics, a better energetical state.

As materials decay, they
emit radiation, eventually disintegrating entirely and becoming innocuous. For
some materials, this process can happen in a fraction of a second. For others,
however, it can take as long as millions of years.

Radioactive waste is categorized broadly as high- or
low-level waste. The former results primarily from fuel used in civilian or
military reactors, and the latter from a range of processes including reactors
and industrial and commercial uses. High-level waste typically refers to
‘spent’ fuel from a nuclear reactor. Most reactors are powered by uranium fuel
rods, which are at the beginning only slightly radioactive. However, when the
fuel rod is ‘spent,’ or used, it is both highly radioactive and thermally hot.

Radioactive materials cannot be treated. Areas contaminated
with radioactive waste are uninhabitable for the lifetime of their radioactive
contents, which can amount to half a million years. There are worldwide efforts
to find ways that high-level wastes can be reliably sealed off from the
biosphere for at least a million years in so-called final repositories.
Isolation from the biosphere is provided by placing several containment
barriers between the waste materials and the external environment, arranged in
succession so that each barrier reinforces the preceding one (multi-barrier
system). However, there is no permanent storage site that is free from the
hazards of radioactive waste. Nuclear waste has been dumped into oceans,
rivers, and lakes, and into the ground. Leaking containers of radioactive
wastes add to this on a daily basis, endangering the earth’s groundwater.

There is no ‘safe’ level of radiation exposure. In the words
of Dr Helen Caldicott (1994), all it takes is one cell and one radioactive decay
for the possibility of cancer, or a genetic defect. Radioactivity impacts the
human metabolism in a wide variety of ways. Its effects can be dramatic,
attacking all body functions in cases of severe exposure but more commonly seen
as causing a range of cancers from exposure over a period of time or impacting
the genetic code, which can result in health problems transmitted to the
following generations.

Untreated sewage
Sewage refers to liquid wastes containing a mixture of human
faeces and wastewater from non-industrial human activities such as bathing,
washing, and cleaning. In many poor areas of the world, sewage is dumped into
local waterways, for the lack of alternatives. For instance, it is estimated
that in Latin America only 15 per cent of wastewater is treated, and sewage
treatment is virtually unheard of in sub-Saharan Africa.

Untreated sewage contains waterborne pathogens that can cause
serious human illnesses including cholera, typhoid, and dysentery. Other
diseases resulting from sewage contamination of water include hepatitis A and
intestinal nematode infections. The World Health Organization (WHO) estimates
that 1.5 million preventable deaths per year result from unsafe water and
inadequate sanitation or hygiene. WHO also estimates that 2.6 billion people
lacked access to improved sanitation facilities in 2008, with the lowest
coverage in sub-Saharan Africa (37%), Southern Asia (38%), and Eastern Asia

Untreated sewage also destroys aquatic ecosystems. Increased
organic matter (from the sewage) breaking down in the river reduces the amount
of dissolved oxygen in the water body as the decomposition process uses up the
available dissolved oxygen. Fish and other aquatic life need that dissolved
oxygen in the water to live.

Eutrophication, which refers to the excessive deposition of
chemical nutrients in water bodies, is one of the numerous problems created by
sewage water pollution. Degradation of the quality of water, reduction in the
number of fish, and increase in biological oxygen demand (BOD) are the effects
of eutrophication.

Urban air quality
Airborne pollutants are emitted into the atmosphere by
burning fossil fuels such as petrol and natural gas, vehicle engines, and
industrial production; by combustion of biomass for agricultural or
land-clearing purposes; and by natural processes such as windblown dust,
volcanic activity, and biologic respiration. Studies have shown that air
pollutants from carbon-based fuels include such contaminants as carbon
monoxide, nitrogen oxides, and other harmful gases and particles.

Various studies suggest that gas and aerosol pollutants are
routinely transported by winds across and between continents and can affect the
air and climate of areas far from their source. However, specifics of climate and
geography play an important role in the persistence and severity of the
pollution. In warm and sunny climates, air in the upper atmosphere can become
warm enough to inhibit vertical air circulation and the dispersion of air
pollutants, trapping smog in the lower atmosphere.

Major health effects associated with outdoor air pollution
include respiratory and cardiovascular disease, lung cancer, asthma
exacerbation, acute and chronic bronchitis, restrictions in activity, and lost
days of work. The WHO estimates that 865,000 deaths per year worldwide can be
directly attributed to outdoor air pollution. Most studies on the health
effects of outdoor air pollution have focused on urban environments
(>100,000 people). People living in large urban areas, especially in
developing countries, where the health risks of air pollution may be
underappreciated and pollution controls lacking, are routinely exposed to
concentrations of airborne pollutants.

Other greenhouse gases include methane—which comes from such
sources as swamps and gas emitted by livestock—and chlorofluorocarbons (CFCs),
which were used in refrigerants and aerosol propellants until they were banned
because of their deteriorating effect on Earth’s ozone layer.

Ozone can be both beneficial and harmful to life on Earth. In
the stratosphere, it prevents most of the harmful ultraviolet rays from
reaching the Earth’s surface. But in the troposphere, near the Earth’s surface,
the ozone is a pollutant.

Used lead acid battery recycling

Lead acid batteries are rechargeable batteries made of lead
plates situated in a ‘bath’ of sulphuric acid within a plastic casing. They can
commonly be recognized as ‘car batteries’. About 6 million tons of lead is used
annually, on a worldwide basis, of which roughly three-quarters goes into the
production of lead-acid batteries, which are used in automobiles, industry, and
a wide range of other applications. Much of this existing demand for lead is
met through the recycling of secondary material and in particular from lead
recovered from used lead-acid batteries. Once the lead acid battery ceases to
be effective, it is unusable and deemed a used lead acid battery (ULAB), which
is classified as a hazardous waste under the Basel Convention (‘The Basel Convention
at a Glance’. Basel Convention. United Nations Environmental Programme.
Available at

Recycled lead is a valuable commodity and for many people in
the developing world the recovery of car and similar batteries (ULABs) is a
profitable business. Many developing countries have entered the business of
buying ULABs in bulk in order to recycle them for lead recovery. ULAB recycling
and smelting operations are often located in densely populated urban areas with
few (if any) pollution controls. In many cases, the local recycling operations
are not managed in an environmentally sound manner and release lead
contaminated waste into the local environment and eco systems in critical
quantities. Despite efforts by government agencies and the industry to
establish safer and more efficient practices, ignorance of the risks of lead
contamination combined with a lack of viable economic alternatives has led to
the systemic poisoning of many poor populations throughout the developing
world. Blacksmith Institute estimates that over 12 million people are affected
by lead contamination from processing of used lead acid batteries throughout
the developing world.

Exposure to lead through inhaling dust, fumes or vapours
dispersed in the air can cause impaired physical growth, kidney damage,
retardation, and in extreme cases even death. Lead poisoning can lead to
tiredness, headache, aching bones and muscles, forgetfulness, loss of appetite,
and sleep disturbance.

Contaminated surface water
With growing populations and an overall increase in living
standards, not only is the overall demand for freshwater pushing limits (one
third of the world now lives in areas of ‘water stress’), but increasing
pollution from urban, industrial, and agricultural sources is also making
available resources either unusable or dangerous to health. Water stress occurs
when the demand for water exceeds the available amount during a certain period
or when poor quality restricts its use. Water stress causes deterioration of
freshwater resources in terms of quantity (aquifer over-exploitation, dry
rivers, etc.) and quality (eutrophication, organic matter pollution, saline
intrusion, etc.).

Every human needs about 20 litres of freshwater a day for
basic survival (drinking and cooking) and an additional 50 to 150 litres for
basic household use. Rural communities around the world traditionally take
their water supply from rivers or from shallow dug wells. Growing
concentrations of people combined with the increasing industrialization of land
use have resulted in many major rivers becoming highly polluted. Key pollutants
in the water systems are typically pathogens arising from human waste (bacteria
and viruses), heavy metals, and organic chemicals from industrial waste.

Water pollution is one of the greatest causes of mortality
that can be linked to environmental factors. Almost five million deaths in the
developing world annually are due to water-related diseases.

According to Population Action International, based upon the
UN Medium Population Projections of 1998, more than 2.8 billion people in 48
countries will face water stress by 2025. Of these countries, 40 are in West
Asia, North Africa, or sub-Saharan Africa. By 2050, the number of countries
facing water stress or scarcity could rise to 54, with a combined population of
four billion people – about 40 per cent of the projected global population of
9.4 billion (Gardner-Outlaw and Engleman 1997; UNFPA 1997).

(Click here for an interactive map on global water stress:

Indoor air pollution
The most significant cause of indoor air pollution in the
developing world is the burning of coal or unprocessed biomass fuels for
cooking, heating, and light.

The practice of cooking with wood or cow dung inside houses
exposes millions of women to fine particles of air pollution in developing
countries. This can cause premature death and lung disease. In poorly
ventilated dwellings, indoor smoke can exceed acceptable levels for small
particles 100-fold. Biomass fuels are typically burned in rudimentary stoves.
Few of these fully combust the fuel, resulting in inefficient use of fuel and
unnecessarily large air emissions.

University of Wisconsin-Madison researchers have linked
indoor air pollution with increased blood pressure among older women. Indoor
air pollution mostly affects health through inhalation, but can also affect the
eyes through contact with smoke. This category of pollution contributes to
nearly three million deaths annually and constitutes four per cent of the
global burden of disease. There is strong evidence that chronic exposure to
indoor air pollutants increases the risk of a range of respiratory illnesses,
including acute lower respiratory infections (ALRI) in children and chronic
obstructive pulmonary disease (COPD) in adults. In addition, chronic exposure
to coal smoke results in increased risk for lung cancer. Women and young
children are at greatest risk because they spend the most time indoors. Studies
have shown that improved stoves or cleaner fuels can cut indoor air pollution
by 50 per cent to 75 per cent.

Artisanal gold mining
Artisanal and small-scale mining (ASM) refers to mining
activities that use rudimentary methods to extract and process minerals and
metals on a small scale. Artisanal miners frequently use toxic materials in
their attempts to recover metals and gems. They work in mostly hazardous
conditions. Further, in the absence of knowledge or any regulations or
standards, toxic materials can be released into the environment, posing great
health risks to the miners and surrounding communities.

Artisanal gold mining releases mercury into the environment
in its metallic form during amalgamation and as mercury vapour during the
burning process. It is one of the most significant sources of mercury release
into the environment in the developing world. According to United Nations
Industrial Development Organization (UNIDO), as much as 95 per cent of all
mercury used in artisanal gold mining is released into the environment. UNIDO
estimates that mercury amalgamation from this kind of gold mining results in
the release of an estimated 1,000 tons of mercury per year, which constitutes
about 30 per cent of the world’s anthropogenic mercury emissions. It is
estimated that there are between 10 million and 15 million artisanal and
small-scale gold miners worldwide, including 4.5 million women and 600,000