This is a fact sheet about a disinfection byproduct that may be found in some public or
private drinking water supplies. It may cause health problems if found
in amounts greater than the health standard set by the United States
Environmental Protection Agency (EPA).
Disinfection byproducts are formed when disinfectants used in water treatment
plants react with bromide and/or natural organic matter (i.e., decaying vegetation)
present in the source water. Different disinfectants produce different types or amounts
of disinfection byproducts. Disinfection byproducts for which regulations have been
established have been identified in drinking water, including trihalomethanes,
haloacetic acids, bromate, and chlorite.
Chlorite is a byproduct formed when chlorine dioxide is used to disinfect water.
EPA has published the Stage 1 Disinfectants/Disinfection Byproducts Rule to regulate
chlorite at a monthly average level of 1 part per million in drinking water.
This standard will become effective for large surface water public water systems
in December 2001 and for small surface water and all ground water public water
systems in December 2003.
Some infants and young children who drink water containing chlorite in excess
of EPA's standard could experience nervous system effects. Similar effects may
occur in fetuses of pregnant women who drink water containing chlorite in excess
of EPA's standard. Some people may experience anemia.
Note: This fact sheet is part of a larger publication adapted from U.S. EPA publication: EPA National Primary Drinking Water Regulations.