These MCLs represent the maximum amount of a chemical that can occur in drinking water without the water being dangerous to human health. Explain the relationship between ppm and ppb and the conversion of these units to milligrams and micrograms per liter. The University of Arizona College of Agriculture is an Equal Opportunity employer, authorized to provide research, educational information, and other services only to individuals and institutions that function without regard to sex, race, religion, color, national origin, age, Viet Nam Era Veteran's status, or disability. For problems or questions regarding this web contact Dr. Kitt Farrell-Poe . Is A Very Finely-Split Hair Worker exposure to certain chemicals is limited to a few parts per million.
Regulations reduce an industrial waste discharge to one part per billion.
Pesticide residues are found in drinking water in the low parts per trillion. Extremely low measurements, and laws and regulations based on them, are growing more commonplace as science perfects increasing sophisticated sensors. Such infinitesimal figures probably don't register with most people. Only scientists and plant managers trying to get exposures and effluents down to levels as find as frog hair comprehend and appreciate their meaning.