Water Pollution: Types, Causes, Effects & Prevention

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Water pollution is one of the biggest threats to the environment today. In this guide, we’ve shared everything you need to know about water pollution, including what it is, how it’s detected, the types of pollution and their causes, the effects of water pollution, and how we can prevent it.

โ” What Is Water Pollution?

Water pollution is the result of harmful substances contaminating a body of water.

All water sources are susceptible to contamination, including:

  • Lakes
  • Streams
  • Rivers
  • Oceans
  • Aquifers
  • Reservoirs
  • Groundwater

The most common harmful substances responsible for water pollution are microorganisms and chemicals.

Water pollution affects the quality of water, typically giving it toxic properties that make it dangerous to humans or the environment.

๐Ÿงช How is Pollution Detected in Water?

In some cases, polluted water is obvious. Solid waste, blue-green algae, and suspended solids can noticeably change the appearance or color of a water supply. However, many pollutants are invisible and may go undetected by sight alone.

The “official” method of detecting pollution in water is to conduct a laboratory test. Samples of water are taken and analyzed for a range of common pollutants.

Scientists also study living organisms in natural bodies of water to detect pollution. Changes in growth or behavior, or even death, are obvious indicators that there are problems with the ecosystem.

Finally, computer models can be used by laboratories to determine the potential dangers in a water supply, using imported data about the water and artificial intelligence to pinpoint pollutants and their sources.

Testing river water contamination

๐Ÿ“‹ Types of Water Pollution

There are several different types of water pollution:

Surface Water Pollution

Surface water is all the water on the surface of the earth, including oceans, rivers, lakes, ponds, streams, and reservoirs. Freshwater surface water sources (or surface water that doesn’t come from the ocean) is often used to supply American homes with drinking water.

The main source of surface water contamination is nutrient pollution, including phosphates and nitrates. Runoff from farm waste and chemical fertilizers are responsible for this contamination.

Industrial and municipal waste also releases toxins into surface water sources due to direct dumping, flooding, or surface runoff. Surface water pollutants may spread far from the original source as they travel through lakes, streams, and oceans.

nitrates from agriculture fertilizers

Groundwater Pollution

Groundwater is water that is stored, or flows, underground. Rainfall and snow causes water to seep through rocks and soils into cracks, crevices and pockets underground, known as aquifers.

The good news is that just over 90% of groundwater supplies are “satisfactory” quality, but that doesn’t mean that groundwater pollution is rare. When water travels through the earth to aquifers, it picks up impurities in the ground, like natural arsenic and heavy metals in the soil, chemicals from the top surface of the ground, and even septic or landfill waste.

At best, polluted groundwater has aesthetic issues, like a bad taste or smell. At worst, certain water pollutants make groundwater unsafe for human consumption. A majorly polluted aquifer may be unsuitable for use for decades or even centuries.

Continue Reading: 9 sources of groundwater pollution

Mtbe groundwater pollution

Ocean Water Pollution

The ocean makes up more than 70% of the earth’s surface, and it’s estimated that 80% of ocean pollution is caused by pesticide leaching, agriculture runoff, and untreated sewage dumping.

Plastic waste is one of the biggest ocean water pollutants. Chemicals and heavy metals also pollute the ocean due to farming activities, industrial gases in the atmosphere, and poor waste disposal practices. Big spills and oil leaks also contribute to ocean pollution.

In many cases, marine pollution originates inland and spreads to the ocean from rivers and lakes. In the case of plastic pollution, debris is blown into the sea or washed into the ocean from sewers and storm drains.

Point Source Pollution

Point source pollution refers to contamination that originates from just one source. Although point source pollution begins in one specific location, it may spread across miles of waterways.

Some examples of point source pollution are:

  • Discharged wastewater (legal or illegal) from an industrial or municipal facility, such as oil refineries, wastewater treatment facilities, and manufacturers
  • Leaking septic systems
  • Oil and chemical spills
  • Illegal waste disposal and dumping

Facilities must adhere to EPA regulations if they wish to discharge waste into a body of water. Companies that don’t stick within the EPA’s limits may face legal ramifications.

Non-Point Source Pollution

Nonpoint source pollution is when several different sources contaminate a body of water. Some examples of non-point source pollution are:

  • Stormwater runoff
  • Agricultural runoff
  • Debris from the land blown into waterways

Non-point source pollution is one of the major sources of water pollution in the US, but – as the name suggests – it’s difficult to identify a single culprit, which means regulating this type of pollution is nearly impossible.

Oil spill example of non-point source pollution

Transboundary Pollution

Transboundary pollution is when polluted or contaminated water crosses the boundaries – or travels from one country into another.

This type of pollution may occur fairly quickly as a result of a disaster, such as flooding, an earthquake, or an oil spill. Alternatively, it could be a slow, steady process caused by water pollutants gradually making their way from one location to another in a flowing river.

๐Ÿ“– The 8 Causes of Water Pollution

Some of the most common causes of water pollution are:

1) Natural Occurrences

Natural occurrences, such as arsenic, mercury, and other toxic substances seeping into water from the earth’s crust, are one possible source of water pollution. Groundwater supplies are most commonly affected by natural pollution, as water seeps through the earth to reach an underground aquifer.

2) Climate Change

An increase in carbon dioxide in the atmosphere has led to rising global temperatures, heating up our water sources. This thermal pollution reduces water’s oxygen content by decreasing the capacity of water that can hold the dissolved gas, disrupting aquatic ecosystems and resulting in the death of marine life.

3) Agriculture and Farming

Improper farming practices, such as the misuse or overuse of pesticides and herbicides, can cause dangerous chemicals to leak into local water sources in surface runoff. Livestock farming can also cause animal waste to pollute water systems.

Agricultural runoff causing contaminated water

4) Industrial Dumping

Illegal dumping or poor waste practices from industrial facilities is another common cause of water pollution. Industrial waste may be physically dumped in water or may leach into water from nearby waste sites. Gases, dust, and particles released into the atmosphere from industrial pollution causes air pollution, which often leads to surface water pollution as a result of rainfall.

5) Maritime Traffic

Tankers, boats, and cargo shipping have a big impact on plastic pollution in the ocean. Oil spills from boats and other water vehicles also pollute our water sources.

6) Landfill and Waste Sites

When waste breaks down in landfill and hazardous waste sites and water flows through that waste, a liquid called leachate is formed. Leachate is highly toxic and may leach into water sources due to surface runoff. There are tens of harmful substances found in landfill sites.

7) Sewage and Wastewater

Toxic chemicals, bacteria, and other microbiological contaminants are found in wastewater and sewage even after treatment. Treated sewage and wastewater are released by sewage treatment plants into local rivers or the ocean, where the pathogens and chemicals in the water breed disease and pollute waterways.

Sewage and wastewater treatment

8) Radioactive Substances

Radioactive pollution is anything that emits more than the natural level of radiation released in the environment. Typically, this type of pollution is caused by discharges from nuclear power plants, uranium mining, military weapon testing, and radioactive medical treatments at hospitals.

Radioactive substances have incredibly long half lives and take up to thousands of years to decay, so they’re highly challenging to dispose of. Contaminants that are improperly disposed of or accidentally released may contribute to land or air pollution, eventually ending up in groundwater and surface water bodies.

๐Ÿ”Ž Who is Affected by Water Pollution?

Water pollution affects every living organism in the environment.

Water is an essential resource that humans, plants, animals, and other organisms couldn’t live without. If water becomes contaminated, it could be harmful to aquatic life, plants, and humans and animals that drink the water.

Humans are lucky that we have the technology to treat our drinking water supplies and make them safe to drink. We’re also lucky that water treatment facilities are monitored by the Environmental Protection Agency to ensure they’re removing dangerous impurities.

However, this doesn’t mean that we’re not affected by water pollution. The more polluted our water sources, the more time, effort, and money must go into treating them.

Plus, polluted water affects wild animals and water species, many of which form a significant part of the human diet.

๐Ÿ“ Effects of Water Pollution

Water pollution has both environmental and human health effects.

Environmental Effects

A healthy ecosystem can only thrive if all living organisms – including plants, animals, and even microorganisms – interact directly or indirectly with one another. If any of these organisms is harmed, a chain reaction occurs, which can threaten all the aquatic organisms within an entire ecosystem.

Algal blooms are often produced in marine environments or lakes as a direct result of water pollution. The excess nutrients introduced into the environment stimulate the growth of algae and plants, reducing the water’s oxygen levels. This causes other plants and animals to suffocate and die, reducing the population. Some algal blooms form neurotoxins that are dangerous to wildlife.

Dead fish floating in polluted water

Our waterways are also contaminated by heavy metals and chemicals from municipal and industrial wastewater.

These toxic contaminants are deadly to aquatic organisms, affecting their ability to reproduce and shortening their lifespans. When these organisms are consumed by larger species, the toxins climb the food chain.

As a result, large fish like tuna and swordfish, which are often eaten by humans, are known to be high in toxins like mercury.

Marine debris is a major threat to our oceans. Large, solid waste can suffocate and strangle animals, killing them instantly or starving them slowly. The likes of soda cans, plastic bags, six-pack rings, and plastic bottles, are blown from landfills or are washed into storm drains and waterways before making their way to the ocean.

Fishing gear like rope, buoys, fishing line and nets is also responsible for littering the ocean and harming the ecosystem.

Shellfish and coral are struggling to survive due to ocean acidification, caused by a reduction in pH due to an increased uptake of carbon dioxide (CO2) from the atmosphere. Acidic waters are also known to affect the nervous systems of marine life like sharks and clownfish.

Human Health Effects

In the majority of cases, humans are lucky enough to not be affected by the consequences of water pollution.

While the marine environment must adapt or die in changing water conditions, humans filter our water supplies to make them safe to drink, cook with, and wash in.

However, that doesn’t mean that our water systems are guaranteed to be safe for use. Every day, millions of Americans drink water that doesn’t meet federal health standards, including water systems that violate EPA limits for harmful impurities.

Up to 1 billion people get sick from drinking polluted water every year. Low-income communities located closest to areas of industrial pollution and agricultural activities are most at risk of water contamination.

You might assume that only developing countries with poor infrastructure are exposed to pathogens in drinking water, but this isn’t the case. Even in wealthy parts of the US, disease-causing bacteria and viruses have been known to pollute drinking water sources, spreading the likes of giardia, cholera, and typhoid.

On a global scale, the World Health Organization estimates that at least 2 billion people per year drink feces in their water.

Boil water notices are issued frequently by local authorities as a result of accidental microbiological contamination – but this contamination isn’t always caught on time.

The most notable example of the potential human health problems associated with polluted water is the Flint, Michigan crisis. Due to a budget crisis, Flint began sourcing drinking water from the Flint River, and aging water infrastructure and a failure to apply corrosion inhibitors to the water caused more than 100,000 residents to be exposed to high lead levels.

Lead is only one of the tens of contaminants that are found in trace levels in potable water. Mercury, arsenic, nitrate and pesticides are all commonly found in public water today, and are known to cause a whole host of health issues when ingested. Most contaminants are particularly dangerous to pregnant women and children.

Swimming in polluted water can also be dangerous, causing respiratory infections, skin rashes, pinkeye, and hepatitis.

Woman breathing difficulty and feeling dizzy

๐Ÿ“‰ How is Water Pollution Managed in the USA?

There are several laws, rules and regulations that aim to manage water pollution in the USA.

National Pollution Prevention Laws and Policies

The major law in place to limit and restrict pollution in the US is the Pollution Prevention Act (P2 Act), which was passed by Congress in 1990.

This law was introduced for the following reasons:

  • America produces millions of tons of pollution per year, which costs tens of billions to control.
  • Industries have “significant opportunities” to limit or prevent pollution through their own operations and material use – but existing regulations or limited resources can prevent these opportunities from being realized.

๐Ÿ“Œ The Environmental Protection Agency implements a national policy according to the Pollution Prevention Act. Under this policy, all industries must prevent or reduce pollution at the source whenever feasible, or recycle or treat pollution that can’t be prevented in an environmentally-safe manner. Only as a last resort should pollution be released into the environment.

Clean Water Act (CWA)

The Clean Water Act was established in 1948 (originally called the Federal Water Pollution Control Act).

This Act was produced to regulate the discharge of pollutants into water sources across the country.

Under the Clean Water Act, the EPA has produced national water quality criteria recommendations for surface water pollutants and implemented pollution control programs to reduce water pollution.

A major way that the EPA has enforced the CWA Act is through the National Pollutant Discharge Elimination System (NPDES) permit program.

This program requires facilities to hold an NPDES permit to discharge pollutants from a point source into water, and authorizes state governments to control limits on which, and how much, pollutants are discharged into local waters. Point sources include man-made ditches and pipes.

Any facility that discharges polluted runoff or municipal or industrial wastes directly into surface water must obtain an NPDES permit. Homes that use a septic system or are connected to a municipal system don’t need an NPDES permit.

Municipal treated tap water

Safe Drinking Water Act (SDWA)

The Safe Drinking Water Act doesn’t manage pollution in water, but it does protect the quality of public water intended for drinking.

The Act was established in 1974 and enforces the Environmental Protection Agency to set standards for water contaminants known to pose a human health risk, which all operators of water treatment facilities must comply with.

The EPA must thoroughly consider the potential risks of a contaminant, and the costs involved in removing it from water, when setting standards. State governments can also be involved in developing standards based on local concern for unsafe or nuisance contaminants.

๐Ÿšฐ How to Reduce Water Pollution

Reducing water pollution is a global effort. You might not feel like your individual actions make a difference, but imagine the impact we could have if we all took individual responsibility to fight water pollution.

We’ve listed some of the best ways to reduce water pollution below.

Reduce your Plastic Consumption

Plastic waste is one of the main sources of water pollution. Reducing your plastic consumption will minimize your plastic contribution to landfills and other waste disposal sites. Plus, you’re telling manufacturers that you won’t use their products if they’re contained in plastic packaging. If you have to buy plastics, recycle where you can.

Woman holding plastic and reusable bags

Look After Your Car

A poorly-maintained car may leak oil, coolant, or antifreeze onto road surfaces – which then travel into water systems through surface runoff. Keep on top of your car’s maintenance to reduce the likelihood of pollution from your vehicle.

On the subject of cars, if you wash your car outside, make sure the water flows into gravel or a grassy area, rather than down your street into a storm drain.

Landscape your Yard

Runoff from your backyard can contribute to water pollution. Landscape your yard to prevent runoff and limit your use of pesticides and herbicides. This is especially important if you have a private well. The well shouldn’t be located at the bottom of a hill or in a ditch.

Don’t Pollute Storm Drains

Be mindful of what you wash down a storm drain. To prevent motor oil pollution, drop off your old oil at your local auto parts store for free, and ensure that spillages are solidified (with sand or gravel) and swept into a garbage can.

Don’t Flush Medications

Only human waste and toilet paper should be flushed down your toilet. Medications should never be disposed of in your waterways. Sanitary products, household cleaning agents, baby wipes, q-tips, dental floss, and anything containing microplastics also shouldn’t be flushed down your toilet or any of your drains.

Disposal of medication waste

Pick up Dog Waste

If you have a dog, pick up its poop. Dog waste contains parasites and pathogenic bacteria that can harm human health if it ends up in our water supplies. Pet waste can also impact oxygen levels in water, potentially affecting fish and aquatic wildlife.

Clean Chemical-Free

Nowadays, there are tens of non-toxic, chemical-free cleaning supplies available for a range of purposes, including unblocking drains, disinfecting surfaces, polishing glass, and washing clothes and dishes. Be mindful of the types of cleaners you use, as many of them will end up down your drain.

Prevent Drain or Sump Pump Contamination

If your home has a cellar drain or a sump pump, make sure the water doesn’t drain into your sewer system. Hire a contractor to inspect your drains if you’re unsure or concerned.

Make Your Voice Heard

Finally, if you want to contribute to change on a larger scale, raise your concerns about water pollution on a public platform. Support the Clean Water Act, which is constantly threatened by industries that have been hurt by the Act. Speak out about the pollutants that aren’t currently monitored or regulated, such as microplastics, pharmaceuticals, and other contaminants that wastewater treatment facilities can’t easily remove.

Make your local government or elected officials aware that you support investments in systems and programs that improve water quality and protect our public waterways, such as lead pipe removal schemes to prevent lead contamination, and improved wastewater treatment facilities.

๐Ÿง  Water Pollution FAQs

What disease can you get from contaminated water?

There are tens of diseases you can get from polluted water depending on what the water is contaminated with. Some of the most common water borne diseases are giardiasis, cholera, hepatitis, typhoid, amebiasis, scabies, gastroenteritis, and worm infections. Some water contaminants don’t cause diseases but are known to have long-term effects, such as immune effects and cancer.

What are the 3 main types of water pollution?

The three main types of water pollution are point-source, nonpoint-source and trans-boundary pollution.

What are the 5 main causes of water pollution?

The five main causes of water pollution are global warming, deforestation, farming, water dumping, and maritime traffic.

What is water pollution in one line answer?

A quick definition of water pollution is this: water pollution is the contamination of water bodies, which negatively affects water quality and impacts the water’s uses.

How can we control water pollution?

We can control water pollution by throwing away litter, reducing our plastic consumption, properly disposing of oils and chemical cleaners, and being mindful of the things we pour into storm sewers. A single person can’t do much to control water pollution – it’s a collective responsibility that all of society needs to take on.

Does water pollution affect drinking water quality?

Yes, water pollution affects drinking water quality. When polluted water is used for tap water supplies, the likes of heavy metals, pesticides and herbicides, and other chemicals end up in our water systems. Water treatment facilities reduce these contaminants according to EPA guidelines, but trace levels of these contaminants can be dangerous in the long term. So, while your water won’t contain solid waste and shouldn’t contain pathogens, it probably contains small amounts of metals, chemicals, and naturally occurring organic matter

  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

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