Cyanide in Water

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Cyanide is a potentially deadly chemical that’s sometimes found at low levels in drinking water.

In this guide, we’ve shared everything you should know about cyanide in water, including how it gets there, how it might harm your health, and how to detect it in your drinking water supply.

๐Ÿ“Œ Key Takeaways:

  • Cyanide is a naturally occurring chemical compound that consists of carbon and nitrogen.
  • This dangerous contaminant may enter water supplies through industrial effluents and natural activities.
  • Potential human health effects of cyanide in water include nervous system damage and effects on the endocrine system.

โ” What Is Cyanide In Water?

Cyanide is a chemical compound that occurs naturally in the environment and in some food products.

This compound of nitrogen and carbon is found in plants including apples, apricots, peaches, almonds, and lima beans. It’s most commonly used in the form of hydrogen cyanide, which is effective in producing resins, synthetic fibers and compounds in metal finishing, paper and plastics manufacturing, textiles, cleaning metal, and electroplating.

Cyanides are also released in cigarette smoke and vehicle exhaust fumes, and some bacteria, algae, and fungi can produce cyanide.

There are two types of cyanide in water: free cyanide and total cyanide.

  • Free cyanide consists of the cyanide ion (CN-) and hydrogen cyanide (HCN).
  • Total cyanide is made up of free cyanide ions, strong metal cyanide complexes, and weak metal cyanide complexes.
Water contaminated with cyanide

๐Ÿšฐ How Does Cyanide Get Into Water?

The most common way for cyanide to enter a drinking water supply is due to accidental releases from manufacturing plants that use cyanide, or from poor waste disposal practices at these plants.

Cyanide released into the atmosphere may make its way into surface water sources due to runoff from landfill and other waste disposal sites, deposits from the atmosphere, or discharges from metal mining processes.

Wastewater treatment facilities may also release effluents containing cyanide into natural waters. Cyanide might be used in some pesticides, and may enter water supplies due to runoff from agricultural land.

Cyanide is also used in chemical weapons, and terrorism or war could result in excess cyanide in the environment.

๐Ÿ”Ž How To Know If Your Water Contains Cyanide

Cyanide has a taste: it’s bitter and acrid, and may have a burning sensation. However, in the tiny trace amounts that are present in water, cyanide is unlikely to have a taste, smell, or appearance.

That means your water could be highly contaminated with cyanide compounds and you wouldn’t know.

There are two ways that you can find out whether or not your water contains cyanide, and how much:

Check Your Water Quality Report

Your Water Quality Report, or Consumer Confidence Report, tells you what your drinking water contains according to tests carried out by your local water utility.

If cyanide is present in your water, it should be featured in this Report. The exact cyanide concentration should be listed, with a note on whether or not this exceeds the legal limit.

You can find your latest Water Quality Report on your water utility’s website.

Test Your Water

An even better way to learn of your water’s cyanide concentrations is to get your water tested by a laboratory.

This will tell you exactly how much cyanide is present in the water that leaves the faucets in your home.

We’ve shared more on testing your water for cyanide later in this article.

Getting tap water tested with tapscore

๐Ÿšฑ Is Cyanide In Drinking Water Dangerous?

Yes, cyanide in drinking water is considered dangerous because there are numerous health risks associated with cyanide exposure.

A report by the CDC noted that even low levels of cyanide can be deadly, and that the form of cyanide (e.g. sodium cyanide or hydrogen cyanide gas) affects the severity of the harmful effects.

Cyanide poisoning occurs when 0.05 milligrams of cyanide are found per deciliter of blood (mg/dL), with symptoms including:

  • Rapid breathing
  • Seizures
  • Loss of consciousness

The EPA noted that cyanide could have the following health effects:

  • Central nervous system (CNS) effects
  • Cardiovascular effects
  • Respiratory effects
  • Enlarged thyroid gland

Exposure to cyanide could also cause skin and eye irritation, deafness, dimness of vision, and enlargement of the thyroid gland (due to cyanide being converted to thiocyanate in the body, which is toxic to the thyroid).

๐Ÿ“‰ Is Cyanide In Tap Water Regulated?

Cyanide in tap water is regulated by the Environmental Protection Agency (EPA) under the Safe Drinking Water Act (SWDA).

The EPA has established a Maximum Contaminant Level (MCL) of 200 PPB (parts per billion) or mg/L (milligrams per liter) for cyanide based on a laboratory test conducted on animals in 1955.

That means that, as long as your water utility reduces cyanide to less than 200 mg/L, this contaminant is considered safe (unable to cause health effects) in your water.

However, some organizations believe that the EPA’s MCL needs to be reevaluated based on emerging evidence of the dangers of cyanide. The Environmental Working Group (EWG) has produced its own more stringent Health Guideline of 150 PPB or mg/L for cyanide to protect against harm to the brain and nervous system.

Testing water quality

๐Ÿงช How To Test For Cyanide In Tap Water

Cyanide isn’t picked up by a standard water test, so you’ll need to pay for advanced testing for this contaminant at a laboratory.

Look for an accredited laboratory that conducts drinking water tests in your area. The average cost of a cyanide water test is $120-$160.

To test your water with this method of cyanide detection, follow the below steps:

  1. Order your test. Choose your preferred test for cyanide and wait for it to be posted to your home.
  2. Collect water samples. Follow the laboratory’s guide to take a sample/samples of your water using the equipment in the test.
  3. Ship the water samples. Send the sample back to the laboratory and wait for your report.
  4. Analyze your results. Your test report should explain whether or not cyanide has been detected and advise you on methods of cyanide removal.

We recommend testing your water for cyanide if you have a specific reason to be concerned about this contaminant, or you live in a region that’s known for cyanide pollution.

๐Ÿ‘ฉ๐Ÿฝโ€โš•๏ธ What To Do If You’re Concerned About Cyanide In Your Water

If you’re concerned about toxic cyanide in your water, here are some things you can do:

  • If your test has detected cyanide water contamination that exceeds EPA legal limits, contact your water supplier with your test results and ask what they’re doing to reduce cyanide levels.
  • You will need to take your own steps to reduce cyanide levels in your water if the concentration detected is within the legal limit or if you use a private well water supply.
  • Also make look at your other possible sources of cyanide exposure (see below) and how you can reduce your overall exposure.

โš ๏ธ Other Ways You Might Be Exposed To Cyanide

Aside from drinking cyanide in your water, there are other ways that you might be exposed to this contaminant:

  • From exhaust fumes – Breathing air polluted with exhaust fumes is the primary source of exposure for most people.
  • Other sources of air pollution – The air you breathe might also be contaminated by cyanide due to emissions from waste incinerators and facilities used by chemical industries.
  • Smoking – Smoking and passive smoking increase your exposure to a specific cyanide form: hydrogen cyanide.
  • In certain workplaces – Some occupations, including firefighting, electroplating, steel manufacturing, and metal cleaning, increase your likelihood of being exposed to cyanide.

๐Ÿ“‘ Final Word: Removing Cyanide From Water

Cyanide is one of the many toxic substances in the environment that can end up in our water systems.

If you don’t want to drink water that contains even trace levels of cyanide, consider a method of water treatment that will remove this contaminant from your water at home.

Waterdrop g3 p800 reverse osmosis system with UV sterilizer attached to water line

Two effective methods of reducing cyanide in water are:

If you’re not sure whether or not a certain water treatment system removes cyanide, contact the manufacturer. You can also check third-party test results for water filters online to get a list of the contaminants that the product can reduce or remove.

  • 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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