Ultimate Guide to the Different Types of Groundwater Contamination

Have you ever wondered what exactly makes water contaminated?

Have you heard people talking about pollution and contamination but feel like you still don’t have a clear idea of which is which?

Did you know that some items you have around your house can potentially be serious water contaminants?

In this article, you’ll learn everything you need to know about water contamination and more. You’ll find out what contamination is and how it differs from pollution, and you’ll also be introduced to several different types of groundwater contamination you might encounter in your neighborhood and around the world.

Each type of soil and groundwater contamination outlined in this article will be explained in-depth so you’ll have a better understanding of where they come from and what they do. You’ll be able to find out the many risks associated with these types of contaminants, and you’ll learn whether or not it’s possible to clean them up once they’ve entered groundwater supplies or not.

After a quick read through this article, you’ll be much better educated about the contamination of ground and surface water where you live. You’ll know what to be on the lookout for and how you can make some changes around your home to improve the quality of water nearby, and you’ll be better able to make some solid decisions when it comes to keeping the groundwater in your city healthy.

Read on to learn more.

What is Contamination?

Before you can look into different types of groundwater contamination, you should know what exactly constitutes contamination in the first place. Basically, a contaminant is any substance found in water that shouldn’t be there. Chemically speaking, water is made up of hydrogen and oxygen. If anything other than hydrogen and oxygen is present in water, then that water has been contaminated. It’s worth noting, however, that even other forms of hydrogen can potentially be contaminants, too.

There are two different types of groundwater contamination sources: point and non-point. Point sources are those from which the contamination comes directly. They include sites of leaking chemicals and oil, broken and leaking septic tanks, and anywhere a spill takes place. Groundwater contamination from landfills is also considered a point source of contamination. Non-point sources include agricultural sites where runoff from pesticides and other chemicals eventually seeps into the ground as well as factories and construction sites where runoff is a problem.

When contamination takes place, it may mean the water is unable to be used for human consumption, but it doesn’t always mean this. Sometimes, contaminants may be present in lower levels, or they may be natural contaminants that aren’t considered dangerous. For example, most water contains minerals like copper and calcium that aren’t a problem when they don’t build up too much in that particular supply. Other times, even dangerous levels of contaminants may be able to be removed with proper treatment, and water that is put through a treatment facility may be able to be cleaned up properly for human use.

When dangerous contaminants are present and can’t be removed from the water, this is known as pollution. Pollution is a type of contamination, but not all contaminants end up polluting the water.

Natural Contaminants

If you’re out walking in the woods and come across a pristine spring untouched by humans, that water is still likely to be contaminated. Why is this? It’s because natural contaminants are a normal part of any water supply. Water that exists in nature is always going to have something in it, even if it’s just decaying leaves or animal waste. Many times, natural water contaminants include a buildup of minerals and even chemicals that can be found in rocks and soil. Although a small amount of these minerals isn’t a problem, too much can cause mineralization, which may dangerous in certain situations.

1. Hydrogen Sulfide

groundwater contamination

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Where does it come from?

When organic materials begin to decompose, hydrogen sulfide is a common byproduct. This can happen from something as simple as leaves and plants decaying in the water, but it might also come from dead animals and fish.

How does it reach groundwater?

For the most part, this type of contamination affects surface water where animals and plants may be decomposing. However, if an animal dies in an area where groundwater is near the surface, it may be possible for hydrogen sulfide to seep through to the groundwater below.

What are its risks?

In low levels, hydrogen sulfide may only cause a little bit of burning in the throat or nose. However, if it’s present in water at very high levels, it could cause dizziness, severe headaches, nausea, trouble breathing, or even seizures and coma.

Which areas are the most affected?

Natural, untreated sources of water are the most heavily affected by the potential for hydrogen sulfide. However, while this is a natural type of contaminant, it might also be found in areas where runoff from construction sites and factories is present, as it is sometimes a byproduct of these places too.

Can it be removed from water?

Yes. Hydrogen sulfide can be removed from water through aeration. Although it’s very dangerous at high levels, it’s fairly easy to remove.

2. Radon Gas

contamination in water

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Where does it come from?

Radon gas is a radioactive substance. However, it’s present in many natural situations where uranium deposits in rocks begin to break down. It’s also found in water near nuclear power plants.

How does it reach groundwater?

Like hydrogen sulfide, this is more often a problem that affects surface water. However, in some instances, rocks containing uranium deposits are located underground in the water table. When water passes through them, it picks up radon gas and carries it through the groundwater.

What are its risks?

When radon gas builds up in water, it can lead to an increased risk of cancer. The higher the levels of radon, the greater the risk. It may also cause birth defects in unborn children when pregnant women drink this contaminated water.

Which areas are the most affected?

Areas near fracking sites may be more at risk for radon gas in the groundwater. People who live near nuclear power plants may be as well.

Can it be removed from water?

Yes. Even though this is a dangerous substance, radon gas can be removed from water through aeration.

3. Arsenic

contamination of ground water

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Where does it come from?

Arsenic is another substance that is present naturally in rocks, particularly in and around mining sites. As these rocks slowly erode over time, the arsenic within them finds its way into the water.

How does it reach groundwater?

When the natural arsenic in rocks is exposed through mining, fracking, or other activities, water picks it up as it moves through the water table. This contaminates the groundwater in that area.

What are its risks?

If arsenic is present in high levels, it can lead to arsenic poisoning in the water supply. This can lead to arsenic poisoning in humans and animals who drink it, and it may also increase the chances of lung cancer in humans exposed to it frequently.

Which areas are the most affected?

People who live in areas near fracking sites are more at risk for arsenic in their water supplies. People who have wells also have an increased risk of this type of contamination.

Can it be removed from water?

Yes, but it’s difficult. Reverse osmosis and anionic exchange filtration systems seem to be the best methods for removing arsenic from water, but they are costly and might not always work.

4. Chromium VI

groundwater contamination

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Where does it come from?

Chromium is found in many places in nature, including animal waste, plant decay, soil, rocks, and even volcanoes. Chromium is an essential element for human survival, but chromium VI is a much more dangerous version than the common chromium III element.

How does it reach groundwater?

Like most natural contaminants, chromium VI reaches groundwater through exposure to natural sources that contain it, such as rocks and soil. It can also be introduced to groundwater through chemical spills.

What are its risks?

Chromium VI is a recognize carcinogenic, which means it causes cancer. When present in drinking water, it greatly increases the risk of cancer in humans and animals.

Which areas are the most affected?

People who rely on groundwater wells are more likely to be exposed to chromium VI. Those who live in areas near gas companies may be at greater risk of chromium VI spills.

Can it be removed from water?

Yes. Chromium VI can be removed from drinking water with an ion exchange filter unit. This can be costly, but it is effective.

Anthropogenic Contaminants

Anthropogenic is a big word that basically means something that came from humans. If a chemical compound is created by a human or introduced to the environment in a specific location by human intervention, it’s an anthropogenic compound. However, not every manmade contaminant fits well into this category, so it’s often taken to mean any contaminant that exists because of increased human processes and operations in a given area. Agriculture, for example, is one of the leading causes of anthropogenic contaminants in the United States.

5. Pesticides

contamination of pesticide

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Where does it come from?

Pesticide contamination largely comes from agricultural sites. However, it may also be present in residential communities where pesticides are often used to treat lawns.

How does it reach groundwater?

When pesticides are sprayed on plants and it then rains on those plants, the pesticides are picked up by the rainwater and carried through runoff to the nearby soil. From there, they seep through the soil and enter the water table where groundwater is present.

What are its risks?

There are many different types of chemical pesticides present in water samples across the country (and around the world). The risks associated with most of these include nausea and stomach upset, vomiting, and chemical burns on the skin or in the throat. They may also cause seizures and even death in rare instances.

Which areas are the most affected?

People who live in agricultural communities are especially at risk for this type of contamination. Those who live in rural areas and get water from wells have a very high risk.

Can it be removed from water?

Yes, but it’s difficult. Pesticides can be removed from water through nanofiltration or through the use of activated carbon. However, it’s very difficult to remove them completely, and trace amounts are often still present following this type of treatment.

6. Nitrates

groundwater as well

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Where does it come from?

Nitrates are sometimes present in water from natural sources. When fish and animals urinate in water or plants decay, eventually this waste turns into nitrates. However, they may also come from fertilizers and pesticides introduced by humans.

How does it reach groundwater?

Anywhere fertilizer runoff is present, nitrates are sure to be very high in the groundwater as well. Nitrate levels are usually increased in groundwater supplies by fertilizer and waste runoff.

What are its risks?

High levels of nitrates in drinking water can cause acute toxicity in adults and may lead to blue baby syndrome in infants. It can lead to a lack of oxygen in humans.

Which areas are the most affected?

Since fertilizers are a leading contributor of this type of contamination, agricultural areas pose some of the highest risks for nitrate problems in water sources. Once again, those who have wells and live in rural areas are more likely to be exposed to high nitrate levels.

Can it be removed from water?

Yes. Reverse osmosis, ion exchange, and the distillation process all remove nitrates from water.

Chlorinated Solvents

Chlorinated solvents are a type of anthropogenic compound in that they are introduced to the environment because of human interaction. However, they are their own specific category of contaminants because there are so many of them that can potentially cause problems in water sources everywhere. These types of chemicals are common especially around cities and factories, and they have led to some of the worst groundwater contamination disasters in the United States and beyond.

7. Dry Cleaning Fluid

surface water sources

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Where does it come from?

Dry cleaning fluid is a common type of waste dumped from dry cleaning facilities around the country. The chemical name for one of the most common of these fluids is perchloroethylene.

How does it reach groundwater?

When dry cleaning fluid is dumped into water or even onto the ground, it seeps through the soil and reaches the water table below. From there, it can very easily contaminate the groundwater and end up being carried to surface water sources nearby too.

What are its risks?

High levels of chlorine in drinking water can lead to a greatly increased risk of cancer. Since dry cleaning fluid contains a lot of chlorine, it can be a very dangerous contaminant in all but the smallest of amounts.

Which areas are the most affected?

Anyone who lives downstream from a dry-cleaning facility or gets municipal drinking water from a place where there are a lot of dry cleaning facilities may be at risk for this type of contamination.

Can it be removed from water?

Yes, but it is difficult. Carbon filters can remove most chlorine from water, but when it’s present in the form of dry cleaning solution it may be much harder to clean up.

8. Degreasers and Cleaners

cleaners and degreasers

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Where does it come from?

Degreasers and cleaners are common household cleaning chemicals that may be washed into yards in residential communities or dumped on the ground by companies that frequently use them.

How does it reach groundwater?

Any time harsh chlorine-based chemicals are dumped or spilled on soil, they have the potential to seep into the soil and reach the groundwater below. This is most common in larger cities where cleaners and degreasers are used commonly by residents as well as corporations.

What are its risks?

The chlorine and other chemicals present in cleaners and degreasers are usually carcinogenic. They may also cause nervous system and respiratory damage as well as chemical burns and digestive upset.

Which areas are the most affected?

Suburban residential communities are at a greater risk for contamination from this type of substance, as are people who get their water from municipal treatment facilities located near factories where degreasers may be used often.

Can it be removed from water?

Yes, but it is difficult. Carbon filters can absorb the chlorine from this type of contamination, but may not be able to remove it completely.

Salt

Did you know salt can be a contaminant too? Much like other minerals, salt can be present in quantities that are too high for freshwater sources. When this happens, it makes the water unusable for common freshwater purposes—such as drinking—and, in effect, contaminates the water. Of course, saltwater itself isn’t necessarily a bad thing, but it needs to stay in the oceans where it belongs and be kept far away from freshwater locations in order to improve overall water quality.

9. Salinity

salinity increases in groundwater

Where does it come from?

Salt can end up in freshwater from a number of different sources, but it often comes from the ocean. Sometimes it also comes from road salts. Irrigation may also lead to natural sodium found in rocks making its way into freshwater sources.

How does it reach groundwater?

Especially in coastal towns and cities, groundwater pumping may cause nearby ocean water to find its way into the water table. Salt may be washed into groundwater by frequent use of road salts to prevent freezing during colder months in places where this is a common practice.

What are its risks?

When salinity increases in groundwater, it’s eventually carried to surface water sources nearby. This can lead to widespread death in fish that are unable to process salt water. It may also alter the pH of any given water source, which may in turn cause algal blooms to get out of hand.

Which areas are the most affected?

Coastal communities are more likely to suffer from this type of contamination, but it may also take place in areas near agriculture sites and cities where road salt is widely used.

Can it be removed from water?

Yes, but it’s harder than it sounds. The process of desalination basically means boiling salt water until it evaporates and then collecting the evaporated freshwater that has left the salt behind. This is a costly endeavor that may be difficult to do on a large scale.

Conclusion

So, do you feel better about your knowledge of groundwater contamination? Now you should be well-versed in many different types of contamination, and you should be better able to recognize them when you see them, too. If you ever notice anything strange about the water coming out of your sink, you’ll be able to look around your home, yard, and neighborhood to determine whether or not one or more of these potential contaminants may exist in your area. Now that you know there are more types of water contamination than just landfill groundwater contamination, you’ll know what to keep your eyes open for.

You’ll also be better able to choose whether or not you want to get involved trying to clean up the groundwater in your area. While a lot of contaminants are very difficult or even impossible to remove completely from water supplies, some of them can still be cleaned up, and these are the ones you might want to help out with. There are many ways you can get involved cleaning up groundwater sites, and if you live in a larger city, there might already be some nonprofit organizations in the area working to improve the quality of groundwater in the neighborhood.

If not, you can always start cleaning up things yourself. Remember, though, that improving groundwater quality starts at home, and that cutting back on the chemicals and waste you wash down the sink or dump into your yard is a great start toward keeping the water healthy and clean for a long time to come.

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