|  | Public Health Safety | Public Health

The Effects of Excess Sulfates in Drinking Water

Sulfates occur naturally in groundwater and are often present in domestic drinking water supplies as a result. Normal levels of sulfates and hydrogen sulfide have no effect on the people who ingest these substances. However, when the amount of sulfates exceeds normal levels, people may suffer health effects, particularly gastrointestinal problems.

  1. How Do Sulfates Enter the Water Supply?

    • Sulfates occur naturally in groundwater as they are composed of sulfur and oxygen, both of which can be found in soil and rocks. Another form of sulfur that can be present in drinking water is the gas hydrogen sulfide. Hydrogen sulfide is also a naturally-occurring substance in some groundwater. It is present in areas that contain large amounts of decomposing organic material and is mainly caused by sulfate-reducing bacteria reacting with sulfur. In some cases, hot water heaters can also produce hydrogen sulfide, as a magnesium rod that is a part of some of these systems reacts with sulfates that occur naturally in the water.

    Effects of Excess Sulfates

    • When sulfates that are naturally present in water build up in water pipes, sulfate levels in drinking water can exceed the Unites States Environmental Protection Agency's secondary limit of 250 milligrams per liter. When this happens, the amount of sulfates in drinking water can have an impact on public health, potentially causing diarrhea. In most cases, this problem stops in a short amount of time as consumers become used to it. However, it can be more of a problem in infants, the elderly and people with underlying health conditions, as prolonged diarrhea can cause dehydration.

    Effects of Excess Hydrogen Sulfide

    • Excessive levels of hydrogen sulfide can also pose a threat to public health, although high levels are usually easier to detect; they produce a smell of rotten eggs and a strong taste. Ingestion of high levels of hydrogen sulfide can cause nausea and illness. Bathroom and kitchen items that are made from materials such as silver and copper can become tarnished by hydrogen sulfide.

    Management

    • The EPA's secondary limit for levels of sulfate in drinking water is a guideline only and is not enforceable by law. However, some public water suppliers may opt to manage these levels according to the guidelines. As the process of removing sulfate is a very difficult one, the easiest treatment is usually to chlorinate the water to kill the sulfate-reducing bacteria. This process, followed by filtration, is often used to treat hydrogen sulfide in drinking water, although replacing the magnesium rod in water heaters with one that is made from another material is also an effective method.

Public Health - Related Articles