Cryptosporidium — Controlling a Waterborne Parasite

Despite efforts by the EPA to make drinking water safe, disease-causing organisms, called pathogens, still remain a threat in some areas. In particular, Cryptosporidium has caused several recent outbreaks of cryptosporidiosis, a severe gastrointestinal illness. In 1993, an outbreak in Milwaukee caused 400,000 people to become ill, and more than 50 people died. To reduce the chances of future outbreaks, EPA proposed to establish a regulation for Cryptosporidium in drinking water in 1994. The agency is still researching the parasite but plans on finalizing a standard by November 1998.

* What is it?
* What does it do?
* How does it get into drinking water?
* Don’t water treatment plants eliminate it?
* What is EPA doing to eliminate Cryptosporidium in drinking water?
* What can you do?

What is it?
Cryptosporidium is a pathogenic parasite that is commonly found in lakes and rivers, particularly those contaminated by sewage and animal wastes. The parasite exists as an oocyst, an egg-shell-like covering that protects the microorganism from such hazards chlorine, a disinfectant.
Unfortunately, the Cryptosporidium oocyst is invisible to the naked eye. Only recently have tests been developed to detect it in drinking water.
Of all the Cryptosporidium species, EPA believes that only the species Cryptosporidium parvum causes cryptosporidiosis in humans. But not all oocysts present in water are in the infectious stage.

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What does it do?
Cryptosporidium causes cryptosporidiosis, a severe gastrointestinal illness. When water contaminated with Cryptosporidium oocysts is ingested, stomach acid dissolves the oocyst and frees the microorganism inside. The microorganism usually infects the upper intestinal tract and causes severe gastroenteritis.
Although most people can recover from a case of cryptosporidiosis, the illness can be life-threatening to some people, such as infants, the elderly, pregnant women, or those with compromised immune systems.

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How does it get into drinking water?
Cryptosporidium is typically found in surface water bodies, like lakes, rivers, and streams. It is found in human and animal fecal matter, so water bodies that are contaminated with sewage or animal waste likely contain Cryptosporidium. For this reason, water sources near farms are particularly vulnerable to Cryptosporidium contamination.
Shallow aquifers that are recharged by surface water may also be susceptible to Cryptosporidium contamination. But generally, only surface water sources are affected by the oocyst.
If you do not know where your drinking water comes from, call your water utility and ask. Surface water sources are much more likely to become contaminated with Cryptosporidium than underground aquifers.

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Don’t water treatment plants eliminate it?
Current EPA drinking water standards were not designed to ensure the removal or disinfection of Cryptosporidium. In fact, the current national primary drinking water standards do not contain a regulation for Cryptosporidium. More importantly, the protective oocyst prevents most water treatment plants from killing the microorganism with chlorine, the disinfectant most commonly used to control microbial pathogens. To effectively control Cryptosporidium, the oocysts must be physically removed from drinking water by microfiltration. This is not economically feasible for municipal water treatment facilities.

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What is EPA doing to eliminate Cryptosporidium in drinking water?
In 1989, EPA passed the Surface Water Treatment Rule. Among other things, this rule regulates certain pathogenic microorganisms in drinking water, including Giardia lamblia and viruses. Water treatment plants must remove 99.9% of Giardiaand 99.99% of the viruses. However, the rule did not set a maximum contaminant level goal (MCLG) for Cryptosporidium. It also did not adequately address the removal of pathogenic organisms from highly contaminated source waters (i.e., 99.9% removal of Giardia from highly contaminated water would still contain a significant amount of the microorganism).
For these reasons, among others, EPA proposed to amend the Surface Water Treatment Rule in 1994. As part of these amendments, the agency proposed a MCLG of zero for Cryptosporidium. Since no methods exist to cost effectively reduce Cryptosporidium to zero, the agency proposed the best available technology to reduce the microorganism — filtration. Of note, this proposed rule would only regulate public water systems that serve more than 10,000 people.
In 1996, Congress amended the Safe Drinking Water Act, the law on which all drinking water regulations are based. Part of these amendments require EPA to take into consideration the effects of drinking water contaminants on vulnerable populations, such as infants, the elderly, pregnant women, and those with compromised immune systems. EPA is now seeking public input into how to select a treatment technology to reduce Cryptosporidium in drinking water.
In November 1997, EPA published more data from research it is conducting on Cryptosporidium. For example, the agency now believes that a certain species of the microorganism, Cryptosporidium parvum, is the only form of the parasite infectious to humans. Studies on filtration technologies show that they can reduce Cryptosporidium 99% if operated properly. However, they do not have large scale filtration abilities at a cost the public can afford.
EPA plans on finalizing the new Surface Water Treatment Rule in November 1998. If this proposed rule is finalized as is, it will not ensure that 100% removal of Cryptosporidium from drinking water. Furthermore, it will only pertain to water systems that supply more than 10,000 customers. Similar regulations for smaller water utilities are expected to follow, but not right away.

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What can you do?
If you think your water may be susceptible to Cryptosporidium contamination, or if you are concerned about the possible healtheffects of contamination, EPA recommends you consider one of three options: Boil your drinking and cooking water for at least one minute.

Install a filter under your sink that is certified by the National Sanitation Foundation (NSF) to remove Cryptosporidium. The filter cartridge should be a carbon block with micron size of 1.0 or smaller.

Note: OMNI’s CBF1, CBF3, OT32, and BF7 (with a CB6 filter cartridge) filters are NSF certified to remove Cryptosporidium oocysts from your drinking water!

Purchase bottled water, but be sure this water has been adequately filtered or otherwise treated. This is a more expensive and not necessarily effective option.