Types Of Water Pollution: Forms, Causes And Consequences

typesofwaterpollutionOur accomplishments often come at the expense of potable water: farming, industry, energy production, urbanization, etc. All of these things are, perhaps, manageable in small doses. But the world population has been booming exponentially for more than a century. Unless we can control it (yes, that means having less children and protecting our water), then the future hardly needs predicting.

When it comes to human necessity, water is arguably our most important resource. Eliminate water – and sources of water – and our species would be extinct in less than a week. On that light note I would like to enter us into a discussion of water; namely, water pollution, including all of its forms, causes and consequences. Educate yourself on water pollution with the guide below (every drop counts) and join the thousands of people who have taken this Elixir course: a history of water and humans.

A Brief Introduction To Water Pollution

We hardly need a formal definition to understand the basics water pollution, but essentially pollution in water occurs when a chemical, physical or biological element causes a body of water to become toxic, unusable or inhospitable to living organisms.

There are many forms of natural water pollution that would occur regardless of our existence on this planet. These include things like sulfur springs, erosion, oil seeps (when oil is naturally released by, most commonly, cracks in sedimentary rocks and seabeds), animal excrement, etc. While these forms of water pollution can be devastating, especially when it seems Mother Nature is shooting herself in the foot, they are negligible compared to the damage caused by humans.

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Point-Source, Nonpoint-Source And Transboundary

The three most common terms we use to refer to the nature of water pollution are point-source, nonpoint-source and transboundary. When water pollution issues from a single source, this is called point-source pollution (an example would be chemicals from a single factory). Conversely, when pollution affecting a body of water issues from multiple sources (multiple factories), it is called nonpoint-source pollution.

We use the term transboundary to refer to pollution that is issued from a distant source. We use this term primarily to refer to one type of man-made pollution: nuclear waste. It can, however, also be used for things like landslides, contaminated rivers traveling long distances towards lakes, etc.


When it comes to water pollution that not only makes water unusable, but also malicious, this is biological pollution. The sources can be both natural and man-made, but certainly the most common source is human waste. Many undeveloped parts of the world suffer from a lack of water treatment options and human waste is a breeding ground for bacteria, viruses and parasites. Examples include E Coli, cholera, typhoid, and many, many others.

According to Water.org, there are over 780 million people who live without water access, and over 2.5 billion who use polluted water, the vast majority of it soiled by biological pollution. Increase your biological knowledge in just a few weeks with this introductory course on biology.

Oxygen Depletion

While devastating, oxygen depletion is a very interesting type of water pollution, although it may be less a type of pollution and more of a result of pollution.

A rule of thumb is that more oxygen is better, at least for life in water. Think about the oxygen pumps you often see in fish aquariums. But when things like sewage and biodegradable processing wastes (examples of this would include paper products, non-toxic dyes, etc.) enter a body of water, they break down by monopolizing, and consuming, oxygen. When this happens, bacteria flourish, and the results can be devastating.

The smallest organisms die first, and as they do, the entire food chain collapses until the largest fish are killed; subsequently, animals such as turtles, birds and wildlife that use the body of water are either infected by the bacteria and/or contaminated fish, or are left with no option but to migrate towards a new water source.

Chemical: Metals

The name says it all: this is pollution caused by the release of chemicals, often as it applies to industry and agriculture. Take your knowledge of chemistry to the next level with this five-star Chemistry 101 course.

Oddly enough, metals pose some of the most dangerous and prolific hazards. The United States, while far from perfect, has stricter legislation on metals that can be by-produced. But many other countries still allow the use of mercury, lead, nickel, and other toxic metals to be deposited directly into water sources.

Mining accounts for a significant percentage of chemical pollution, as well. When mines are planned with little or no forethought to how waste will drain away from the mine (which can occur both above and below the surface), then catastrophic amounts of metal can, and do, drain or “leach” into water sources.

Chemical: Acids and Bases

The more commonly known type of chemical pollution is acidic (and basic), although we generally group acids with solvents and organic chemicals, which we’ll discuss next. Acids and bases, like solvents, are by-products of industry. For water to be stable to life, it must remain at a constant, balanced ph level. Needless to say, water that becomes too acidic or basic is able neither to sustain life nor to be used for consumption.

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Chemical: Organic Chemicals

Organic chemicals, which sound harmless enough, are really the most plentiful chemical pollutants in the world. These can be found in clothes (pigments), medicine (pharmaceuticals), plastics, pesticides, and thousands upon thousands of other things we use every day. Industry drives the incessant production of organic chemicals. From the ink on paper to the color of our clothes, organic chemicals are everywhere.

Most people do not take proper disposal seriously: ink cartridges, oil cans, batteries, etc. But all these little things add up to the most proliferous source of toxic organic chemicals in the world. Tied for first are similar causes: irresponsible dumping by industrial companies and the inevitable seepage from agricultural pesticides (when DDT was used extensively, it protected crops but it also passed through ecosystems; deposits built up by attaching to organic matter and, over time, water became toxic with disastrously high levels of organic chemicals).

There are many ways to be a part of the solution to water pollution and our global impact on water ecosystems; this blog post on the best fish to eat for sustainable populations is a good place to start.

Unfortunately, many of the chemicals ever produced still exist; they are waiting for some natural disaster to free them from holding tanks, stagnant poisonous water lands that are harboring billions of pollutants, and, perhaps most widely spread of all, trash dumps and landfills, where plastics will sit preserved for hundreds, and possibly thousands, of years.


Farming can’t catch a break when it comes to water pollution. Nutrient pollution is a result of agriculture, too. The problem is that farming is so competitive and people do not like to spend money on food (ironically, it is the things we need the most that we most dislike spending money on: food and water). The average family spends hundreds of thousands of dollars on housing, transportation, clothing and luxury items, and yet is outraged at the prices of fresh, perfectly grown produce.

Farmers pump their crops full of vital nutrients such as nitrogen and phosphorus, often in the form of fertilizers. Of course, these same nutrients are sought after by plant life in water, so when the excess nutrients drain into nearby water sources, it causes an explosion of overwhelming plant growth (algae and others). This causes further pollution by sucking up all the oxygen (see “Oxygen Depletion” above) and releasing dangerous amounts of carbon dioxide.

Learn more about the elements and how they interact with our environment with this Chemistry of the Elements course (nitrogen and phosphorus are elements, after all).

Suspended Matter

This is a nice way of saying that some chemicals are not water soluble, just as “organic chemicals” is a nice way of saying that some chemicals are water soluble. The former are called suspended matter because they stay “suspended” in the water for a period of time; then they fall to the bottom of the water and create a nice layer of more or less permanent toxicity. As suspended matter continues to accumulate, the water continues to become more and more unbalanced.

Like many forms of pollution, suspended matter creates a chain reaction: more and more chemicals accumulate, which causes the water imbalance to increase exponentially, which causes organisms in the water to die, which, by decomposing, releases even more toxic elements, which makes the problem even worse, and so on and so forth.

Moving Forward

Eventually, unprecedented levels of commitment to fixing this problem must be realized or we will simply run out of water within the next several hundred years, at best. Just like water pollution is exponential, so is the human population. Use this class on the geography of globalization to learn about the complexities of human globalization and how it affects our cultures.