Giardia, Bacteria and Water Treatment:
Controlling Water Borne Parasites
Despite efforts by the U.S. EPA to make drinking waters safe,
disease-causing pollution organisms, called pathogens, still remain a threat in some
areas. In particular, Giardia can cause outbreaks of giardiasis, an intestinal illness
that can cause nausea, anorexia, fever, and severe diarrhea. The symptoms can last for
several days, and giardiasis can be treated with antibiotics. If left untreated, the body
will naturally rid itself of the parasite within a few months in most cases. To reduce the
chances of outbreaks, EPA established an acceptable level for Giardia in drinking waters
in the surface water treatment rule, promulgated in 1989. In November 1998, the agency
plans on establishing regulations that further regulate the parasite. Successful water
treatment is necessary to eliminate this risk.
Doulton Water Filters
remove 99.999% of bacteria, cysts, and any other foreign particles as small as .2 of a
micron.
Giardia is a pathogenic parasite that is commonly found in
lakes and rivers, particularly those contaminated by sewage and animal wastes. The
parasite exists as a cyst, an egg-shell-like covering that protects the microorganism from
such hazards as chlorine, a disinfectant. The cyst also protects the microorganism from
destruction outside the host, leaving it viable. When this is ingested, viable cysts can
infect their new hosts.
What does it do?
Giardia causes giardiasis, an intestinal illness. When
solutions contaminated with Giardia cysts are ingested, stomach acid dissolves the cyst
and frees the microorganism inside. The microorganism usually infects the upper intestinal
tract and causes discomfort.
Although most people can recover from a case of giardiasis,
the illness can be life-threatening to some people, such as infants, the elderly, pregnant
women, or those with compromised immune systems.
How does it get into drinking water?
Giardia is typically found in surface bodies, like lakes,
reservoirs, rivers, and streams. It is found in human and animal fecal matter, so bodies
that are contaminated with sewage or animal waste likely contain Giardia. For this reason,
sources near farms are particularly vulnerable to Giardia contamination.
Shallow aquifers that are recharged by surface waters may
also be susceptible to Giardia contamination. But generally, only surface sources are
affected by the cyst.
If you do not know where your drinking waters comes from,
call your utility and ask. Surface waters source are much more likely to become
contaminated with Giardia than underground aquifers.
Don't government facilities eliminate parasites?
Current EPA drinking waters and standards require the removal
or disinfection of Giardia. The current national primary drinking waters standards require
plants to both filter and disinfect waters to ensure 99.9% of the Giardia cysts are
removed or disinfected. But sometimes the protective cyst prevents plants from killing the
microorganism with disinfection. To effectively control Giardia, the cysts must be
physically removed from drinking waters. Doulton
Water Filters remove 99.999% of bacteria, cysts, and any other foreign particles as
small as .2 of a micron.
Is it in well waters?
Giardia can be found in well waters, particularly if the well
is located on a farm. But the most common sources of Giardia are surface sources, like
rivers, streams, lakes, and reservoirs.
What can you do?
If you think your source may be susceptible to Giardia
contamination, or if you are concerned about the possible health effects of contamination,
EPA recommends you consider one of these options:
Boil your drinking and cooking liquids for at least one
minute - or - Install a filter under your sink that is certified by the National
Sanitation Foundation to remove Giardia. The filter cartridge should be a carbon block
with micron size of 1.0 or smaller.
Doulton Water Filters
remove 99.999% of bacteria, cysts, and any other foreign particles as small as .2 of a
micron.
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