Healthy Drinking Waters for M A S S A C H U S E T T S S a f e a n d h e a l t h y l i v e s i n s a f e a n d h e a l t h y c o m m u n i t i e s Hydrogen Sulfide and Sulfate in Private Drinking Water Wells ann em rivate well owners are responsible for the af er H quality of their drinking water. !e U.S. d P an x e Environmental Protection Agency (EPA) does l m/A not regulate private wells. Homeowners with o .c o t o private wells are generally not required to test h p k c their drinking water, although local Boards o of Health or mortgage lenders may require ©ist well water testing. While there is also no state requirement to have your well water tested, the taste. Water supplies with 1.0 milligram per Massachusetts Department of Environmental liter (parts per million) of hydrogen sulfide may Protection (MassDEP) recommends that all be corrosive and tarnish copper and silverware. homeowners with private wells do so, and use a It can also produce yellow or black stains on state certified testing laboratory. Homeowners kitchen and bathroom fixtures and can affect can use the public drinking water standards as the appearance and taste of some foods and guidelines to ensure drinking water quality. beverages. Treatment options for hydrogen !ere is no drinking water quality standard sulfide include aeration, granular activated set for hydrogen sulfide in water. !ere is, carbon filtration, and shock chlorination to kill however, a Secondary Maximum Contaminant the sulfur-producing bacteria. Level (SMCL) set for odor in drinking water, Sulfates are part of naturally occurring which would capture the presence of hydrogen minerals contained within soil and rock forma- sulfide. !e SMCL for sulfate in drinking water tions. As water percolates down through the is 250 milligrams per liter (parts per million) as soil, these minerals can dissolve releasing sul- established by the EPA. fates into groundwater. Treatment options for sulfates include reverse osmosis, distillation, Summary and ion exchange. Hydrogen sulfide is a gas that is produced naturally by decomposing organic material Potential Health Effects and sulfur-reducing bacteria. Hydrogen sulfide Hydrogen sulfide gas is flammable and poi- gives water a nuisance “rotten egg” smell and sonous at high concentrations. Usually it is 1 Healthy Drinking Waters for Massachusetts H y d r o g e n S u l f i d e a n d S u l f a t e i n P r i v a t e D r i n k i n g W a t e r W e l l s not a health risk at concentrations present in household water. Build up of hydrogen sulfide concentrations in confined areas has been known to cause adverse health effects. Water with dissolved hydrogen sulfide gas alone does not cause disease. In rare cases, however, hydrogen sulfide odor may be from wastewater pollution, which can contain disease-causing contaminants. !erefore, arrange to test the water for bacterial con- tamination if sewage is the likely source of hydrogen sulfide. In addition, you may want to conduct a detergent test if wastewater contamination is suspected. Elevated sulfate levels in water may have a e n g laxative effect that can lead to dehydration and a e G is mostly a concern for infants. While a nui- is m/L o .c sance, sulfur-oxidizing bacteria do not present o t o h p any known human health risk. k c o ©ist Indication of Hydrogen Sulfide and Sulfate in Drinking Water Hydrogen sulfide gas produces o an offensive brass utensils. It can also cause yellow or black an anz “rotten egg” or “sulfur water” odor and taste in stains on kitchen and bathroom fixtures. e M ik the water. m/ M • Most people can detect hydrogen sulfide in Coffee, tea, and other beverages made o .c o t o water at concentrations as low as 0.5 with hydrogen sulfide contaminated water may h p k c o milligrams per liter. be discolored and the appearance and taste of ©ist • Concentrations less than 1 milligram per cooked foods can be affected. liter give water a “musty” or “swampy” odor. ut o enh • A concentration of 1 – 2 milligrams per liter High concentrations of dissolved hydrogen a y M gives water the “rotten egg” smell and makes sulfide can foul the resin bed of an ion ex- mm o it very corrosive to household plumbing. change water softener. When hydrogen sulfide m/T o .c o odor occurs in treated water, yet was not t o h p The odor may be noticeable k only when the originally detected in the pre-treated water, c o water is initially turned on or when hot water this usually indicates the presence of sulfate- ©ist is running. Heat forces the hydrogen sulfide reducing bacteria in the treatment system. Ion gas into the air, which may cause the odor to be exchange units provide a convenient environ- particularly offensive in the shower. ment for these bacteria to grow. A “salt-loving” bacteria, which uses sulfates (naturally occur- Hydrogen sulfide is corrosive to metals ring from dissolved minerals in soil and rock) such as iron, steel, copper, and brass. It can as an energy source, produces a black slime tarnish silverware and discolor copper and inside ion exchange units. Regular treatment 2 Healthy Drinking Waters for Massachusetts H y d r o g e n S u l f i d e a n d S u l f a t e i n P r i v a t e D r i n k i n g W a t e r W e l l s system maintenance can help prevent this tions to avoid contamination and to obtain a from occurring. representative sample. !e amount present in water determines which treatment method will Sulfates can cause a scale buildup be most effective. Because hydrogen sulfide is a in water pipes as do other minerals, and may also be as- gas dissolved in water that can easily escape or n n a m s sociated with a bitter taste in the water. While be lost from the sample, a water sample must s o r G not as common, another form of bacteria that be chemically stabilized immediately after col- o k i e H feeds on sulfides (sulfur-oxidizing bacteria) lection in order for the laboratory to accurately / m o c . o converts sulfides to sulfates which results in measure its concentration. Be sure to contact t o h p k a dark slime that can clog plumbing and/or the laboratory for the proper sample bottle, c o t s i stain clothing. chemical preservative and instructions. If © wastewater pollution is the suspected source Sources of Hydrogen Sulfide and of contamination, collect a separate sample Sulfate in Drinking Water to test for bacteria. In addition, you may also Hydrogen sulfide gas occurs naturally in want to conduct a test for detergents. e n g a groundwater and can result from a number Most state certified laboratories have a e G is of sources. standard test for detecting sulfate levels in ell w m/L o am .c r o • Decomposing underground deposits of water. Follow laboratory instructions carefully t o x B h e l p k to avoid contamination and to obtain a organic matter such as decaying plant c o m/A o good sample. .c material can produce hydrogen sulfide. ©ist o t o h p • Wells drilled in shale, sandstone, or near k c Reducing Sulfide/Sulfate in o coal or peat deposits may also be sources of ©ist hydrogen sulfide. Your Drinking Water • Sulfur-reducing bacteria feed on the !e recommended treatment varies with the naturally occurring sulfates in water, amount and form in which hydrogen sulfide producing hydrogen sulfide gas as a and/or sulfate are detected in the water, and by-product. whether you need whole house treatment • Water heaters may also be a potential (point-of-entry), or point-of-use treatment for source of hydrogen sulfide gas. If a drinking and cooking. At elevated levels, whole magnesium rod is in the tank to prevent house treatment is usually recommended. water heater corrosion, the rod can Other options include buying bottled water— chemically reduce naturally occurring especially if the main problem occurs with food sulfates to hydrogen sulfide. and beverage preparation, or installing a new well. Depending on the source of the problem, Testing for Hydrogen Sulfide and a new well may need to be installed that is Sulfate in Private Drinking Water Wells either deeper or more shallow than the existing Since hydrogen sulfide is detectable by taste well, or be located within a different area on and smell, a laboratory test is not needed to your property to avoid the sulfur source. If the detect its presence, however, a test is necessary hydrogen sulfide is a result of sulfur bacteria to determine the amount of hydrogen sulfide in the pipes, chlorinating your well can kill the in water. To determine the level, arrange to bacteria. However, this is not a permanent so- test your drinking water at a state certified lution and the bacteria can re-occur. For more laboratory. Carefully follow laboratory instruc- information on shock chlorination procedures, 3 Healthy Drinking Waters for Massachusetts H y d r o g e n S u l f i d e a n d S u l f a t e i n P r i v a t e D r i n k i n g W a t e r W e l l s refer to the fact sheet: Bacteria in Drinking Water Wells.