A protozoan associated with the disease cryptosporidiosis in humans. The
disease can be transmitted through ingestion of drinking water, person-to-person
contact, or other exposure routes. Cryptosporidiosis may cause acute diarrhea,
abdominal pain, vomiting, and fever that last 1-2 weeks in healthy adults, but
may be chronic or fatal in immuno-compromised people.
Contact between a person and a chemical. Exposures are calculated as the
amount of chemical available for absorption by a person.
A protozoan, which can survive in water for 1 to 3 months, associated with
the disease giardiasis. Ingestion of this protozoan in contaminated drinking
water, exposure from person-to-person contact, and other exposure routes may
cause giardiasis. The symptoms of this gastrointestinal disease may persist for
weeks or months and include diarrhea, fatigue, and cramps.
Maximum Contaminant Level (MCL)
Maximum permissible level of a contaminant in water which is delivered to any
user of a public water system.
Inorganic compounds that can enter water supplies from fertilizer runoff and
sanitary wastewater discharges. Nitrates in drinking water are associated with
methemoglobinemia, or blue baby syndrome, which results from interferences in
the bloods ability to carry oxygen.
Chemical molecules that contain carbon and other elements such as hydrogen.
Organic contaminants of concern to drinking water include chlorohydrocarbons,
pesticides, and others.
Per person; generally used in expressions of water use, gallons per capita
per day (gpcd).
Point-of-Use Water Treatment
Refers to devices used in the home or office on a specific tap to provide
additional drinking water treatment.
Point-of-Entry Water Treatment
Refers to devices used in the home where water pipes enter to provide
additional treatment of drinking water used throughout the home.
Elements that undergo a process of natural decay. As radionuclides decay,
they emit radiation in the form of alpha or beta particles and gamma photons.
Radiation can cause adverse health effects, such as cancer, so limits are placed
on radionuclide concentrations in drinking water.
The potential for harm to people exposed to chemicals. In order for there to
be risk, there must be hazard and there must be exposure.
A specific treatment method required by EPA to be used to control the level
of a contaminant in drinking water. In specific cases where EPA has determined
it is not technically or economically feasible to establish an MCL, EPA can
instead specify a treatment technique.
Bacteria that are used as indicators of fecal contaminants in drinking water.
(often E. coli)
The property of a chemical to harm people who come into contact with it.
Chemicals that, as liquid, evaporate into the air.
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