Environmental Pollution
Its Sources and Effects

Below we discuss major aspects of this study area, from definitions to pollution types & sources as well as wide-ranging pollution effects.

Oil Pollution Emissions Photo: Graeme MacLean

C O N T E N T S Pollution Definitions Introduction to Pollution Types of Pollution Sources of Pollution Pollution Effects on Humans, Other Animals & Trees and Plants Pollution Effects on Environment Conclusion

So what is pollution? In order to get a better understanding of it, let’s have a look at some common definitions.

Perhaps the overriding theme of these definitions is the ability of the environment to absorb and adapt to changes brought about by human activities.

In one word, environmental pollution takes place when the environment cannot process and neutralize harmful by-products of human activities (for example, poisonous gas emissions) in due course without any structural or functional damage to its system.

In fact, “the due course” itself may last many years during which the nature will attempt to decompose the pollutants; in one of the worst cases – that of radioactive pollutants – it may take as long as thousands of years for the decomposition of such pollutants to be completed.

Pollution occurs, on the one hand, because the natural environment does not know how to decompose the unnaturally generated elements (i.e., anthropogenic pollutants), and, on the other, there is a lack of knowledge on the part of humans on how to decompose these pollutants artificially.

Why does pollution matter?

It matters first and foremost because it has negative impacts on crucial environmental services such as provision of clean air and clean water (and many others) without which life on Earth as we know it would not exist.

Introduction to Environmental Pollution

Although pollution had been known to exist for a very long time (at least since people started using fire thousands of years ago), it had seen the growth of truly global proportions only since the onset of the industrial revolution during the 19th century.

The industrial revolution brought with it technological progress such as discovery of oil and its virtually universal use throughout different industries.

Technological progress facilitated by super efficiency of capitalist business practices (division of labour – cheaper production costs – overproduction – overconsumption – overpollution) had probably become one of the main causes of serious deterioration of natural resources.

At the same time, of course, development of natural sciences led to the better understanding of negative effects produced by pollution on the environment.

Environmental pollution is a problem both in developed and developing countries. Factors such as population growth and urbanization invariably place greater demands on the planet and stretch the use of natural resources to the maximum.

It has been argued that the carrying capacity of Earth is significantly smaller than the demands placed on it by large numbers of human populations. And overuse of natural resources often results in nature’s degradation.

Types of Environmental Pollution

There are three major types of environmental pollution:

• Air pollution
• Water pollution
• Soil pollution (contamination)

For a list of other pollution types, please see the Types of Pollution article.

Some of the most important air pollutants are sulfur dioxide, nitrogen dioxide, carbon monoxide, ozone, volatile organic compounds (VOCs) and airborne particles, with radioactive pollutants probably among the most destructive ones (specifically when produced by nuclear explosions).

Please refer to the Summary of Air Pollutants article for a brief overview of sources and effects of air pollutants.

Water pollutants include insecticides and herbicides, food processing waste, pollutants from livestock operations, volatile organic compounds (VOCs), heavy metals, chemical waste and others.

Some soil pollutants are: hydrocarbons, solvents and heavy metals.

Sources of Environmental Pollution

Fossil Fuel Sources of Environmental Pollution

In modern industrialized societies, fossil fuels (oil, gas, coal) transcended virtually all imaginable barriers and firmly established themselves in our everyday lives.

Not only do we use fossil fuels for our obvious everyday needs (such as filling a car), as well as in the power-generating industry, they (specifically oil) are also present in such products as all sorts of plastics, solvents, detergents, asphalt, lubricating oils, a wide range of chemicals for industrial use, etc. (8)

Combustion of fossil fuels produces extremely high levels of air pollution and is widely recognized as one of the most important “target” areas for reduction and control of environmental pollution.

Fossil fuels also contribute to soil contamination and water pollution. For example, when oil is transported from the point of its production to further destinations by pipelines, an oil leak from the pipeline may occur and pollute soil and subsequently groundwater. When oil is transported by tankers by ocean, an oil spill may occur and pollute ocean water.

Of course, there are other natural resources whose exploitation is a cause of serious pollution; for example, the use of uranium for nuclear power generation produces extremely dangerous waste that would take thousands of years to neutralize.

But there is no reasonable doubt that fossil fuels are among the most serious sources of environmental pollution.

Power-generating plants and transport are probably the biggest sources of fossil fuel pollution.

Common sources of fossil fuel pollution are: (9)

Industry:

• Power-generating plants
• Petroleum refineries
• Petrochemical plants
• Production and distribution of fossil fuels
• Other manufacturing facilities

Transport:

• Road transport (motor vehicles)
• Shipping industry
• Aircraft

Fossil fuel combustion is also a major source of carbon dioxide (CO2) emissions and perhaps the most important cause of global warming. Learn more about the causes and effects of global warming here.

Other (Non-Fossil Fuel) Sources of Environmental Pollution

Among other pollution sources, agriculture (livestock farming) is worth mentioning as the largest generator of ammonia emissions resulting in air pollution. Chemicals such as pesticides and fertilizers are also widely used in agriculture, which may lead water pollution and soil contamination as well.

Trading activities may be another source of pollution.

For example, it’s been recently noted that packaging of products sold in supermarkets and other retail outlets is far too excessive and generates large quantities of solid waste that ends up either in landfills or municipal incinerators leading to soil contamination and air pollution.

Residential sector is another significant source of pollution generating solid municipal waste that may end up in landfills or incinerators leading to soil contamination and air pollution.

We discuss air pollution causes in more detail here.

Environmental Pollution Effects on Humans, Other Animals & Plants

There is no doubt that excessive levels of pollution are causing a lot of damage to human & animal health, plants & trees (including tropical rainforests) as well as the wider environment.

All types of environmental pollution – air, water and soil pollution – have an impact on the living environment.

The effects in living organisms may range from mild discomfort to serious diseases such as cancer to physical deformities (for example, extra or missing limbs in frogs).

Experts admit that environmental pollution effects are quite often underestimated and that more research is needed to understand the connections between pollution and its effects on all life forms.

Environmental Pollution Effects on Humans

We know that pollution causes not only physical disabilities but also psychological and behavioral disorders in people.

We are discussing the effects of air pollution and specific air pollutants in more detail in the Air Pollutants article.

The following effects of environmental pollution on humans have been reported:

Air Pollution in Philippines
Photo: Jim D Stitch

Air pollution (18, 19)

• Reduced lung functioning
• Irritation of eyes, nose, mouth and throat
• Asthma attacks
• Respiratory symptoms such as coughing and wheezing
• Increased respiratory disease such as bronchitis
• Reduced energy levels
• Headaches and dizziness
• Disruption of endocrine, reproductive and immune systems
• Neurobehavioral disorders
• Cardiovascular problems
• Cancer
• Premature death

We discuss air pollution effects in more detail here.

Water pollution (20)

Waterborne diseases caused by polluted drinking water:

• Typhoid
• Amoebiasis
• Giardiasis
• Ascariasis
• Hookworm

Waterborne diseases caused by polluted beach water:

• Rashes, ear ache, pink eye
• Respiratory infections
• Hepatitis, encephalitis, gastroenteritis, diarrhoea, vomiting, and stomach aches

Conditions related to water polluted by chemicals (such as pesticides, hydrocarbons, persistent organic pollutants, heavy metals etc):

• Cancer, incl. prostate cancer and non-Hodgkin’s lymphoma
• Hormonal problems that can disrupt reproductive and developmental processes
• Damage to the nervous system
• Liver and kidney damage
• Damage to the DNA
• Exposure to mercury (heavy metal):
  
  • In the womb: may cause neurological problems including slower reflexes, learning deficits, delayed or incomplete mental development, autism and brain damage
  • In adults: Parkinson’s disease, multiple sclerosis, Alzheimer’s disease, heart disease, and even death

Other notes:

• Water pollution may also result from interactions between water and contaminated soil, as well as from deposition of air contaminants (such as acid rain)
• Damage to people may be caused by fish foods coming from polluted water (a well known example is high mercury levels in fish)
• Damage to people may be caused by vegetable crops grown / washed with polluted water (author’s own conclusion)

Soil contamination (21)

• Causes cancers including leukaemia
• Lead in soil is especially hazardous for young children causing developmental damage to the brain
• Mercury can increase the risk of kidney damage; cyclodienes can lead to liver toxicity
• Causes neuromuscular blockage as well as depression of the central nervous system
• Also causes headaches, nausea, fatigue, eye irritation and skin rash

Other notes:

• Contact with contaminated soil may be direct (from using parks, schools etc) or indirect (by inhaling soil contaminants which have vaporized)
• Soil contamination may also result from secondary contamination of water supplies and from deposition of air contaminants (for example, via acid rain)
• Contamination of crops grown in polluted soil brings up problems with food security
• Since it is closely linked to water pollution, many effects of soil contamination appear to be similar to the ones caused by water contamination

Environmental Pollution Effects on Animals

Air Pollution (22)

• Acid rain (formed in the air) destroys fish life in lakes and streams
• Excessive ultraviolet radiation coming from the sun through the ozone layer in the upper atmosphere which is eroded by some air pollutants, may cause skin cancer in wildlife
• Ozone in the lower atmosphere may damage lung tissues of animals

Water Pollution (23)

• Nutrient pollution (nitrogen, phosphates etc) causes overgrowth of toxic algae eaten by other aquatic animals, and may cause death; nutrient pollution can also cause outbreaks of fish diseases
• Chemical contamination can cause declines in frog biodiversity and tadpole mass
• Oil pollution (as part of chemical contamination) can negatively affect development of marine organisms, increase susceptibility to disease and affect reproductive processes; can also cause gastrointestinal irritation, liver and kidney damage, and damage to the nervous system
• Mercury in water can cause abnormal behavior, slower growth and development, reduced reproduction, and death
• Persistent organic pollutants (POPs) may cause declines, deformities and death of fish life
• Too much sodium chloride (ordinary salt) in water may kill animals (24)

Other notes:

• We also assume that some higher forms of non-aquatic animals may have similar effects from water pollution as those experienced by humans, as described above (author’s own conclusion)

Soil Contamination (25)

• Can alter metabolism of microorganisms and arthropods in a given soil environment; this may destroy some layers of the primary food chain, and thus have a negative effect on predator animal species
• Small life forms may consume harmful chemicals which may then be passed up the food chain to larger animals; this may lead to increased mortality rates and even animal extinction

Environmental Pollution Effects on Trees and Plants

Air Pollution (26)

• Acid rain can kill trees, destroy the leaves of plants, can infiltrate soil by making it unsuitable for purposes of nutrition and habitation
• Ozone holes in the upper atmosphere can allow excessive ultraviolet radiation from the sun to enter the Earth causing damage to trees and plants
• Ozone in the lower atmosphere can prevent plant respiration by blocking stomata (openings in leaves) and negatively affecting plants’ photosynthesis rates which will stunt plant growth; ozone can also decay plant cells directly by entering stomata

Water Pollution

• May disrupt photosynthesis in aquatic plants and thus affecting ecosystems that depend on these plants (27)
• Terrestrial and aquatic plants may absorb pollutants from water (as their main nutrient source) and pass them up the food chain to consumer animals and humans
• Plants may be killed by too much sodium chloride (ordinary slat) in water (28)
• Plants may be killed by mud from construction sites as well as bits of wood and leaves, clay and other similar materials (29)
• Plants may be killed by herbicides in water; herbicides are chemicals which are most harmful to plants (30)

Soil Contamination

• May alter plant metabolism and reduce crop yields (31)
• Trees and plants may absorb soil contaminants and pass them up the food chain

Environmental Pollution Effects on Wider Environment

Apart from destroying the aquatic life in lakes and streams, acid rain can also corrode metals, damage surfaces of buildings and monuments, and cause soil acidification.

Pollution of water may cause oxygen depletion in marine environments and severely affect the health of whole ecosystems. (32)

Environmental Pollution - Conclusion

Environmental pollution is causing a lot of distress not only to humans but also animals, driving many animal species to endangerment and even extinction.

The transboundary nature of environmental pollution makes it even more difficult to manage – you cannot build stone walls along the borders of your country or put customs cabins at every point of entry to regulate its flows into your country.

Everything on our planet is interconnected, and while the nature supplies us with valuable environmental services without which we cannot exist, we all depend on each other’s actions and the way we treat natural resources.

It’s widely recognised that we are hugely overspending our current budget of natural resources – at the existing rates of its exploitation, there is no way for the environment to recover in good time and continue “performing” well in the future.

Perhaps we should adopt a holistic view of nature – it is not an entity that exists separately from us; the nature is us, we are an inalienable part of it, and we should care for it in the most appropriate manner. Only then can we possibly solve the problem of environmental pollution.

Last update: October 2008