Are there special customers who should be notified prior to a city changing from chlorine to chloramines for water disinfection?

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In general, before a water utility makes such a change, all customers are usually notified but health care providers, dialysis patients, pet store owners, or others who care for fish should receive special notice.

Why are the special customers typically notified? The primary reason for the notification is to give consumers and users of the water time to make adjustments to remove chloramines from the water where small residual levels can cause health problems for humans, fish, or other animals.

Just what is chloramine and how does it affect health care providers, dialysis patients, and pet store owners?

Chloramines are a combination of chlorine and ammonia and chloramines are regarded as a more reliable disinfectant in the water distribution system than chlorine alone because chloramines last longer. Chloramines also produce lower levels of disinfection byproducts than chlorine. To form chloramines, chlorine and ammonia are used in combination with each other. Ammonia is naturally occurring and is found in groundwater throughout many areas. Ammonia can also be added to the water in very small quantities.

Chlorine and chloramines must be removed from the water used in kidney dialysis machines. There are two ways to remove these disinfectants:

  • Adding ascorbic acid, or
  • Using a granular activated carbon treatment. Medical centers that perform dialysis are responsible for treating the water that enters dialysis machines. We notified all medical facilities to treat the water to remove chloramines, just as they do for chlorine. Home dialysis service companies usually make the modifications needed, however you should check with your equipment supplier and/or physician. Chlorinated water is safe for kidney dialysis patients to drink. If you have any questions, please consult your physician.

What about fish owners? Chloramines are toxic to cold-blooded animals, such as fish, because it passes through the gills of the fish or the skin of the reptile, and directly enters the bloodstream. Fish tank and pond owners, including zoos, hobbyists, restaurants, fish markets, grocery stores with lobster tanks, and bait shops with fish containers, must have appropriate filtration equipment or use water treatment products to neutralize chloramines. Chlorinated water should be treated before it is added to your tank, aquarium, pond, or goldfish bowl. Carbon filters on your tank may not remove chloramines from the tap water that is added directly to your tank. Chloramines will not dissipate from boiling or holding water in open, standing containers.

The following tips are helpful in protecting your fish from the presence of chloramines or chlorine residuals:

  • Chemical additives for dechloraminating water you add to your tank or pond (makeup water) are available at pet/fish supply stores.
  • Tap water used with artificial sea salts for makeup water in saltwater fish tanks must be dechlorinated.
  • Water additions should be as small as possible, so the fish are not stressed as the biological filter cleanses the water. Avoid large water changes.

Carbon filters should be operated at a slow rate for best chloramines removal. They should be monitored carefully to determine when the carbon media has reached the end of its useful life and needs to be changed. Manufacturers often indicate the maximum number of gallons that can be filtered before renewal of the filters is required. Check with the supplier for proper operation. Testing the residual from the filter will help determine the best filtration rate. So why do water utilities use chloramines if they must take precautions to notify special consumers? In the past, chlorine was typically used for both primary and secondary disinfection in the water treatment process to guard against bacterial growth in the distribution system. Over time, many water utilities experienced elevated levels of trihalomethanes (THM's) with chlorine as a disinfectant. THM's are a suspected carcinogen (cancer-causing agent), created in small amounts as a by-product when natural organics in water combine with chlorine.

The U.S. Environmental Protection Agency (EPA) lowered the standard to 80 parts per billion on January 1, 2002, as the maximum level of THM's allowed in drinking water. The EPA recommends chloramines as a disinfectant and as a way to avoid THM formation. Chloramines ensure water remains bacteria-free for a longer time period than chlorine. So while clearly being a better alternative than chlorine gas, chloramines themselves remain a disinfection chemical that special needs water consumers must be notified of before the use of, as well as any problems resulting in the use of.

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