What are Nitrates and How to Remove them from Well Water

What are Nitrates?

A nitrate molecule has one nitrogen atom bonded to three oxygen atoms. Nitrides, which only have two oxygen atoms, are often lumped in with nitrates. Nitrates and nitrides share many properties, and nitrates break down into nitrides through biological processes.

Organic nitrates have long hydrocarbon chains, and are mostly synthesized to produce medicines. These aren’t a contamination concern in food or drinking water. Inorganic nitrates are negatively charged ions that are usually bound to a positive-charged metal cation. This negative charge also attracts water molecules, making inorganic nitrates water-soluble. These are the molecules that can make your well water dangerous to drink.

These chemicals exist in nature, and can be found everywhere, including air, dirt and water. They’re also synthesized, and are heavily used in agriculture. Nitrates are strong oxidation agents, so they’re common to many chemical processes, including ceramic, metal and glass manufacturing. Nitrates are also a great food preservative, and are used to cure a range of meat products, including sausages, ham and bacon.

All living creatures create nitrates as part of natural processes, including humans. Most of the nitrates produced by our bodies come from the breakdown of L-arginine, an important protein-building amino acid. On average, the human body makes 62 milligrams of nitrates each day. For comparison, a hot dog contains around 10 mg of nitrates.

Are Nitrates Good or Bad?

If you’re just looking into this topic, the information about these chemicals can seem contradictory. How can nitrates simultaneously be beneficial to your body and a major health concern? It depends on how they interact with your body.

20% of the nitrates we’re exposed to comes from food, and, on average, just 3% comes from processed meat. Nitrates turn meat pink, giving hot dogs, ham and bacon their distinct color. Most of the nitrates we get from food come from green leafy vegetables, like spinach, bok choy and lettuce. Many root vegetables, including carrots and beets, are also high in nitrates.

Nitrates are used to preserve meat, because they kill bacteria. This process also creates nitrides, as bacteria attempt to consume the nitrate-laced meat. Together, nitrides and nitrates give preserved meats their unique flavor.

Thanks to improved shipping and refrigeration, we don’t need to rely on these preservatives to keep meat from spoiling. Instead, nitrates and nitrides are added for flavor, eliminating the need for aging. This allows these meats to come to market sooner, decreasing their cost. This direct use allows for greater control of nitride content, keeping it at safe levels.

Why are there health concerns about nitrates in meats, but not vegetables? Preservative nitrates are converted into nitrites, while nitrates from fresh foods are mostly converted into nitric oxide. Nitrides have a stronger attraction to red blood cells than oxygen. This can interfere with your body’s ability to absorb oxygen from the air. Nitric oxide (NO) is used for cell communication and regulation of the endothelial system.

This system controls lymph nodes and blood vessels. When NO reaches cells in blood vessels, it enables vasodialation. Nitrate consumption is important to maintain the levels of NO your body needs to regulate your cardiovascular system.

Nitrates also form into nitrosamines, which are carcinogenic. These chemicals form in high heat, like grilling. Nitrosamines also form when nitrides react with amines in our bodies. Regulations have lowered the amount of nitrates and nitrides used in meats, while Vitamin C is sometimes added to nitrate and nitride-containing products to block nitrosamine formation.

Once nitrates and nitrides are inside your body, they can react with amines and amides, forming N-nitroso compounds (NOCs.) These are the most potent, broadest acting carcinogens we know of today. NOCs and nitrosamines increase the chance of colon cancer. Nitrates and nitrides also make it harder for the thyroid gland to absorb iodine, which leads to cysts and other growths.

Fortunately, it’s relatively easy to regulate the amount of nitrates you consume, and consume them in a way that reduces the formation of harmful chemicals. Unfortunately, managing nitrate consumption from unregulated water sources requires a significant amount of work.

Why are Nitrates a Problem in Well Water?

Nitrates are highly water-soluble. If they’re released into the environment, they end up in ground water.

Nitrate contamination tends to be highest in well water near agricultural communities. This is due to the use of ammonium nitrate and potassium nitrate in fertilizer. Nitrates also show up in water near golf courses, which are also heavy users of these fertilizers. In some areas, industrial runoff is also a factor. Animal waste also has high levels of nitrates. This contamination can come from flooding, seepage from your sewage system, or from large livestock farms and feedlots near your well.

While these chemicals add flavor to meats, in plain water, they don’t have a detectable taste or smell. The only way to know the amount of nitrates in your water is through testing.

What Health Problems are Caused by Nitrates in Water?

High levels of nitrates are a serious concern for infant health. Oxygen bonds with nitrides before it will bond with red blood cells. This can lead to methemoglobinemia. While it’s uncommon in adults, infants up to 6 months old are particularly susceptible to this disease. This is due to their size, as well as their undeveloped digestive tracts.

While nitrates in adults might be broken down into nitrogen oxide or nitrides, infants convert most nitrates into nitrites. As oxygen levels drop in the baby’s bloodstream, its skin starts to look blue. This has given methemoglobinemia the nickname “Blue Baby Syndrome.” The elderly, people with compromised immune systems, and people with cardiovascular issues should also be wary about high levels of nitrates in their water.

Nitrates in water react the same as nitrates in preserved meats, creating toxic chemicals like nitrides and NOCs. Over time, consumption can lead to increased heart rate, muscle weakness, ptyalism (saliva overproduction) and depression. High doses of nitrates can lead to short term hypotension, arrhythmia, headaches, dizziness and flushing.

Nitrates and nitrides from water can prevent the uptake of iodine in the thyroid gland, which may lead to malformations. This directly affects the thyroid’s function, and the resulting nodules can constrict the esophagus. This makes it harder to breathe and swallow.

Will High Nitrate Levels Affect the Health of My Pets?

Naturally occurring bacteria in our bodies convert nitrates into nitrites. Ruminant animals, like cows and horses, have high levels of these bacteria in their digestive systems, which makes them susceptible to nitrate poisoning. The chance of poisoning for most other animals, including dogs, cats and birds, is probably low.

However, there is some concern that the same thyroid problems that show up in humans could show up in other mammals, particularly dogs. Unfortunately, there haven’t been enough studies on this to have a clear picture on nitrates’ health effects on these pets. While carcinogenic effects are possible, the short lives of most pets means they don’t have enough time for chemicals like NOCs to build up in their bodies.

Nitrates are a natural part of the nitrogen cycle in aquariums, but it’s easy for levels to rise to a point that they cause health problems in fish and increase algae blooms. For most aquatic systems, it’s recommended to keep levels below 40 PPM for saltwater tanks and 25 PPM for freshwater tanks.

If you’re breeding fish, or are having problems with algae blooms, levels should be lowered to under 10 PPM. Most nitrate problems are related to waste buildup, but tap water levels are also a factor.
It’s generally recommended to use water with nitrate levels below 10 PPM in aquariums.

At What Levels Do Nitrates Become Unsafe?

The EPA recommends no more than 1 milligram of nitrates in a liter of water, or less than 10 parts per million, to prevent Blue Baby Syndrome. Since it doesn’t take long for nitrate exposure to lead to health problems and death, the agency takes this seriously. If a water test is over this limit, the municipality must issue a Tier 1 public notification.

This is a public alert within 24 hours of receiving the test results. Water results between 5 and 10 PPM require additional health information to be added to the yearly water quality report, which is sent to all users of the system.

Well water doesn’t fall under the EPA’s jurisdiction, so it’s up to you to monitor your water and add equipment to keep nitrates at safe levels.

How and When Should I Test My Well Water?

Nitrates have no flavor or odor. The only way to detect their presence is with testing. It also isn’t something you can do just once. Geology has a major effect on nitrate contamination, because it determines how runoff reaches your water supply. That means your neighbor may have a well with little to no contamination, while your well has high levels of contaminates. You also need to retest if there’s a change in the landscape. These changes are caused by flooding, landslides and construction.

Nitrates should be tested at least every two years, although some health organizations recommend yearly testing. Bringing a baby into the home? Taking a water test will ensure you’re doing what you can to reduce health effects. Made a change to your water treatment system? Have your water retested, so you can be sure your equipment is working correctly.

Nitrate tests measure nitrogen in either nitrate and nitrile compounds, or just nitrates. If you get a test that looks for both compounds, you need to treat your water if levels are above 10 mg per liter. However, keeping levels below 2 mg/L is recommended. If the test only looks at nitrates, you need to treat the water for nitrates if the result of 45 mg/L or higher.

Nitrate tests can be divided into field tests and laboratory tests. You can do a field test yourself. The kit includes one or two chemicals that are added to a water sample. This reacts with the nitrates, changing the water’s color. This color varies depending on the concentration of nitrates. Following the instructions is critical for getting an accurate result. To make this easier, new tests require fewer steps, and some work with smartphone apps. These apps use your phone’s camera to measure the color of the water, making it easier to get an accurate reading.

If you’re using a test with a color chart, the water must have light shining through it to get an accurate color match. If you hold the water sample against the chart, the paper will block some of the light, making the water look darker than it really is.

With a laboratory test, you collect a water sample and mail it to a lab. The lab uses a spectrometer to measure the amount of nitrates in the water. As with any other water test, you want to send your sample to a state certified laboratory. Your state’s Department of Health website should have a list of approved labs. If your field test results are different from previous tests, it’s a good idea to verify the results with a lab test.

Conductivity tests may indicate nitrate contamination. This test measures the amount of dissolved minerals based on the water’s electric conductivity. If the result is twice as high as the water’s hardness, it indicates high levels of sodium, sulfates, chloride or nitrate contamination. You need to do further testing to figure out which of these minerals is increasing your water’s conductivity.

Do Nitrates Make Water Unsafe to Use, Outside of Consumption?

No. Nitrates aren’t absorbed through the skin, so it’s safe to use water with high levels of these chemicals for uses other than drinking and cooking. They have no effect on bathing, washing dishes or cleaning clothes. The levels of nitrates in your water also won’t affect its use on plants, negatively or positively.

How Do I Remove Nitrates from My Water?

If your tests results changed recently, you should start by checking the condition of your well. The well casing needs to be at least a foot above ground. A cracked case can let surface water in, which carries the highest level of contaminates. Once you’ve ruled out this contamination, you need to add a nitrate filtration system. There are two filter technologies that are used to remove nitrates from water: ion exchange and reverse osmosis.

Ion exchange filters are mostly used to soften water. These filters don’t screen out contaminates. Instead, they use filter media to replace contaminates with salt.

All ion exchange filters remove nitrates, but the effectiveness of water softeners is limited. That’s due to the level of attraction between the sodium ions and other ions in the water. The attraction between these ions and nitrates is relatively weak, while it’s stronger for other chemicals, particularly sulfides.

If you have high levels of sulfides in your water, the softener will absorb almost no nitrates. Adding a water softener can lower the amount of nitrates in your water, but since the amount they remove varies widely depending on the presence of other contaminates, they aren’t recommended as a primary treatment method.  

Ion exchange filters built for nitrate removal use selective media. This media has low attraction to multivalent ions, including arsenate and sulfate. This makes it easier for the media to pick up nitrates. This media is also called anion resin, and is made of either tributylamine or triethylamine. Aside from the media, these systems function exactly like an ion exchange water softener.

They have a separate brine tank, and need to recharge periodically, soaking the media in salt water and draining off flush water. Ion exchange filters are up to 90% effective. That means water that contains 50 PPM of nitrates going into the media tank will have just 5 PPM when it comes out.

Undersink reverse osmosis filters can be more cost effective than whole house ion exchange filters. Osmosis is a process where water-soluble chemicals move across a barrier between two bodies of water. This movement continues until water on both sides of the barrier have equal concentrations of the chemical.

Reverse osmosis uses pressure to force chemicals into water on one side of the barrier. This creates clean water on one side, and dirty water on the other side. Reverse osmosis is effective at removing a wide range of chemicals, including nitrates.

Reverse osmosis systems require additional filters to protect the RO membrane. Most systems are built with carbon and sediment filters, which strip out particles and chlorine that can damage the membrane. Whole house systems are prohibitively expensive. However, since nitrates are only a concern for drinking and cooking, an undersink system is a practical, affordable treatment solution.

These systems tap into your kitchen faucet’s water supply, processing water and sending it to a separate faucet. Due to the pressure required to force water through the RO membrane, flow rates are slow. To get around this, most systems have a built-in storage tank. This acts as a buffer, giving the system time to filter water, so it’s ready when you need it. RO systems remove between 80 and 90% of nitrates in water.