Skip to content
Ntro

Are Sulfites in Water Bad for You? Separating Fact from Fiction

•
8 min read

Over 5% of asthmatics are sensitive to sulfites, but the sulfur compounds found in natural drinking water are typically different and pose far less risk. This common confusion often leads to questions about the safety of our tap water, but it's crucial to distinguish between food additives and natural mineral compounds. This guide will clarify the real effects of sulfur compounds in your water.

Quick Summary

Differentiating between sulfites, sulfates, and hydrogen sulfide is key to understanding drinking water safety. While sulfates can cause aesthetic and digestive issues, and hydrogen sulfide creates an odor, these are distinct from the allergic reactions some people have to food-based sulfites.

Key Points

  • Sulfite vs. Sulfate: True sulfites are food additives that can cause allergic reactions in sensitive individuals, while sulfates are naturally occurring minerals in water.

  • Laxative Effects: High concentrations of sulfates in drinking water can cause a temporary laxative effect, particularly in infants and people new to the water source.

  • Aesthetic Nuisances: Hydrogen sulfide gas, often mistaken for sulfites, causes the 'rotten egg' smell and metallic taste in water, but is generally not a health risk.

  • Asthmatic Sensitivity: Individuals with asthma are more prone to allergy-like reactions from food-based sulfites; these symptoms are distinct from effects of waterborne sulfur compounds.

  • Treatment Solutions: Methods like reverse osmosis, distillation, and specific filters can effectively remove high levels of sulfates and hydrogen sulfide from water.

  • Test Your Water: If you are concerned about sulfur in your water, the most reliable approach is to test your water source with a certified laboratory.

In This Article

Understanding Sulfur in Your Water

When most people ask, "Are sulfites in water bad for you?" they are actually thinking of the sulfur compounds that occur naturally in water, namely sulfates and hydrogen sulfide. True sulfites, chemical compounds with the formula $SO_{3}^{2-}$, are most commonly used as preservatives in foods and pharmaceuticals and are not typical contaminants of natural drinking water. A common exception is residual sulfite that remains after some wastewater treatment processes.

This article will explore the effects of the more common waterborne sulfur compounds to provide a clear picture of what might be in your glass.

The Role of Sulfates in Drinking Water

Sulfates are salts of sulfuric acid ($H_2SO_4$) that occur naturally in groundwater as water passes through soil and rock formations containing minerals like gypsum. At certain concentrations, they can cause a bitter taste (above 250 ppm) and have a temporary laxative effect, especially for those new to the water source, particularly infants. The EPA's Secondary Maximum Contaminant Level (SMCL) for sulfates is based on these aesthetic concerns. High sulfate levels can also contribute to plumbing corrosion.

The Notorious 'Rotten Egg' Smell: Hydrogen Sulfide

Hydrogen sulfide ($H_2S$) is a gas known for its offensive rotten egg odor. This gas causes unpleasant taste and smell, is corrosive to plumbing and metals, and can cause staining. Hydrogen sulfide is often produced by sulfur-reducing bacteria (SRB), which are non-disease-causing microbes found in oxygen-deficient areas like wells and water heaters.

The Real Danger: Sulfite Sensitivity

It's important to differentiate between sulfur compounds in water and the sulfites used as food and drug additives. Sulfite sensitivity, primarily affecting asthmatics, can cause respiratory, skin, and gastrointestinal symptoms, and rarely, anaphylaxis. These reactions are linked to ingested or exposed food-based sulfites, not natural water contaminants. Those with sulfite sensitivity should focus on avoiding products containing sulfites, such as certain dried fruits, wines, and medications. For more information, resources like Food Allergy Canada are available.

Testing and Treating Sulfur in Your Water

Testing is recommended for private well owners concerned about sulfates or hydrogen sulfide. For public water, water quality reports are typically available. Various treatment methods exist depending on the identified issue.

Comparison of Water Treatment Methods

Treatment Method Best For Effectiveness Advantages Disadvantages
Reverse Osmosis (RO) Sulfate & Other Contaminants Very High (93-99%) Removes a wide range of dissolved solids and pathogens. Slower, generates wastewater, higher upfront cost.
Distillation Sulfate & Other Contaminants Very High (~100%) Highly effective at removing dissolved minerals. Slow process, uses a lot of energy.
Ion Exchange High Sulfate Levels Very High Effective for large quantities of sulfate. Requires regeneration with a salt solution; more common for commercial/public use.
Activated Carbon Filter Low Hydrogen Sulfide Good Effective for odor and taste at low concentrations. Requires frequent filter replacement.
Oxidizing Filter Moderate Hydrogen Sulfide Good Converts $H_2S$ into solid particles for filtering. Requires regular backflushing and maintenance.
Shock Chlorination Sulfur-Reducing Bacteria Temporary Effective for killing bacteria in the well system. Not a permanent solution; bacteria often return.
Water Heater Adjustment Hydrogen Sulfide from heater Specific Replacing the magnesium anode rod with an aluminum one. Only addresses the hot water supply.

Conclusion

Concerns about "sulfites in water" are often related to a misunderstanding of naturally occurring sulfur compounds like sulfates and hydrogen sulfide, which primarily cause aesthetic and nuisance issues, not the allergic reactions associated with food-based sulfites. While high levels of sulfates can have a temporary laxative effect, particularly on infants, and hydrogen sulfide causes unpleasant odors and corrosion, these are generally not considered significant health hazards for most people. Effective treatment options, including reverse osmosis and various filtration systems, are available to address these issues. For those with sulfite sensitivity, the focus should be on avoiding sulfites in foods and medications. Testing your water is recommended to understand the specific compounds present and determine appropriate treatment.

Testing and Treating Sulfur in Your Water

  • Test Your Water Source: Use a state-certified lab to accurately measure sulfur compound levels in your well or tap water.
  • Understand Different Compounds: Learn to distinguish between naturally occurring sulfates and hydrogen sulfide and the food additive sulfites.
  • Address Nuisance Issues: Implement a targeted treatment system, like aeration for hydrogen sulfide or an oxidizing filter, to remove unpleasant odors and tastes.
  • Consider Health-Specific Concerns: For households with infants or individuals with severe sulfite sensitivity, use treatments like reverse osmosis or distillation to ensure the lowest possible exposure.
  • Maintain Your Treatment System: Regularly operate and maintain your chosen water treatment system according to manufacturer guidelines to ensure its effectiveness over time.

FAQs

Q: What is the difference between sulfites and sulfates in water? A: Sulfates are naturally occurring mineral compounds in water, while sulfites are mainly used as preservatives in foods and beverages and are not typically found in natural drinking water.

Q: Can I smell if there are high levels of sulfates in my water? A: No, sulfates are odorless. The rotten egg smell often associated with sulfur in water comes from hydrogen sulfide gas, which is a different compound.

Q: How do sulfates get into drinking water? A: Sulfates are dissolved into groundwater as it moves through mineral deposits in rocks and soil, such as gypsum.

Q: What are the main health effects of high sulfate water? A: The primary health effect of high sulfate levels is a temporary laxative effect, especially for people not accustomed to it, with infants being most susceptible.

Q: Is the rotten egg smell from hydrogen sulfide dangerous? A: For most household concentrations, hydrogen sulfide is primarily a nuisance and not a health risk. In high, enclosed concentrations, it could pose a risk, but this is rare.

Q: What can cause a rotten egg smell specifically from hot water? A: The rotten egg odor from hot water can be caused by sulfur-reducing bacteria in the water heater or a chemical reaction involving the magnesium anode rod.

Q: What is the best way to remove sulfates and hydrogen sulfide from my well water? A: The best method depends on the concentration and type of sulfur compound. Options include reverse osmosis or ion exchange for sulfates and aeration or oxidizing filters for hydrogen sulfide.

Q: Is sulfite sensitivity related to the sulfur in my drinking water? A: No. Sulfite sensitivity is a reaction to food and beverage additives, not the natural mineral compounds found in water. The health issues are distinctly different.

Q: Will a standard water softener remove sulfates from my water? A: No, a standard water softener will not remove sulfates. While the process is similar to ion exchange used for sulfate removal, it requires a different type of resin.

Q: Can I test my water for sulfur at home? A: While you can use test kits, the most accurate way to determine specific levels of sulfates and hydrogen sulfide is by using a state-certified laboratory.

Q: Does boiling water remove sulfates? A: Distillation, which involves boiling water and condensing the steam, can remove almost 100% of sulfates. However, simply boiling water at home does not effectively remove sulfates.

Q: How do sulfur-reducing bacteria thrive in my plumbing? A: These bacteria live in oxygen-deficient areas, often found in deep wells, plumbing systems, and water heaters, where they convert sulfates into hydrogen sulfide gas.

Citations

Frequently Asked Questions

Sulfates are naturally occurring mineral compounds found in water, while sulfites are chemical preservatives used in food and beverages. The health concerns associated with each are different: sulfates mainly cause digestive issues at high levels, while sulfites trigger allergic reactions in sensitive people.

It is highly unlikely for sulfites in drinking water to cause an allergic reaction. The allergenic sulfites are typically found in food and drinks where they are added as preservatives. The natural sulfur compounds in water, like sulfates, cause different, less severe issues.

The rotten egg smell is caused by hydrogen sulfide gas, which can occur naturally in well water or be produced by sulfur-reducing bacteria in low-oxygen environments like plumbing or water heaters. This gas is generally a nuisance rather than a health hazard.

For most healthy adults, high sulfates in water are not a significant health risk, though they can have a temporary laxative effect. Infants are more sensitive and may experience diarrhea. The EPA's limit is based on aesthetic issues like taste rather than toxicity.

Several methods can remove sulfates, including reverse osmosis, distillation, and ion exchange. These are often necessary for private well owners with significantly high sulfate concentrations.

Simple boiling will not effectively remove sulfates. Distillation, which involves boiling and re-condensing the water, is required to leave the dissolved solids behind. For hydrogen sulfide gas, boiling can help dissipate some of the odor, but it may return.

Testing your water is the most accurate way to know for sure. However, if the rotten egg smell is more pronounced in your hot water or comes and goes, it's often a sign of sulfur-reducing bacteria. A certified lab test can confirm the presence of bacteria and sulfur compounds.

Yes, but standard filters like activated carbon or a water softener are not effective for sulfates. You would need a specialized system, such as a reverse osmosis or anion exchange unit, to remove sulfates.

No. Sulfite sensitivity is a reaction to food and beverage additives, not the natural mineral compounds found in water. The health issues are distinctly different.

While you can use test kits, the most accurate way to determine specific levels of sulfates and hydrogen sulfide is by using a state-certified laboratory.

Distillation, which involves boiling water and condensing the steam, can remove almost 100% of sulfates. However, simply boiling water at home does not effectively remove sulfates.

These bacteria live in oxygen-deficient areas, often found in deep wells, plumbing systems, and water heaters, where they convert sulfates into hydrogen sulfide gas.

The EPA has a non-enforceable Secondary Maximum Contaminant Level (SMCL) of 250 mg/L for sulfates, based on aesthetic concerns like taste and laxative effects, not health risks for the general population.

References

  1. 1
    Sulfate In Well Water - MN Dept. of Health
  2. 2
    Adverse reactions to the sulphite additives - PMC
  3. 3
    Drinking Water: Sulfur (Sulfate and Hydrogen Sulfide) - Nebraska Extension Publications
  4. 4
    Sulfite Allergy & Sensitivity: Symptoms, Tests & Treatments - Cleveland Clinic
  5. 5
    How to Remove Sulphate from Water - Pure Aqua, Inc.

Related Topics:

#Health Risks #Water Quality #drinking water #sulfite sensitivity #hydrogen sulfide #water treatment #sulfates #sulfites in water

Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice.