You are here:
INVESTIGATIONS OF WATERBORNE DISEASE OUTBREAKS
Impact/Purpose:
The objective is to determine the number of reported waterborne disease outbreaks in the U.S. and to characterize each with regard to the causative agent, type of defect, water source, and type of water treatment system. This information is needed for risk assessment, to obtain feedback on the utility of current regulations and the need for additional regulatory measures, and to identify previously unrecognized agents.
Description:
From 1971-2000, there were about 751 waterborne disease outbreaks recognized and reported, with over 500,000 associated cases of illness. From 1989-1994, of 90 total outbreaks, 2% were associated with untreated surface water, 30% with untreated ground water, 42% with treatment deficiency, 18% with distribution system deficiency, and for 8% the defect was not established. Most of the 90 outbreaks were associated with ground waters (62%), and about 27% with surface water (springs, other sources) accounted for the rest.
The SDWA Amendments of 1996 added a requirement for EPA and the Centers for Disease Control and Prevention (CDC) to jointly carry out "pilot waterborne disease occurrence studies for at least five major U.S. communities or public water systems" and "prepare a report on the findings of the pilot studies, and a national estimate of waterborne disease occurrence." This work would help assess the effectiveness of currently employed treatment tradeoffs in these communities, as well as provide information to balance the benefits of disinfection versus potential risks. As such, the research would provide EPA with feedback on the effectiveness of the SWTR and the TCR, as well as provide supplementary information to guide the long-term ESWTR and the GWDR.
EPA has collaborated with scientists at CDC for 30 years to track waterborne disease outbreaks in the U.S. and publish a summary either annually or every two years. In addition, EPA requests supplemental information on coliform monitoring for microbial related outbreaks. This information provides the Agency with feedback on the etiologic agents of concern (especially newly recognized pathogens), the types of problems associated with outbreaks, and the utility of EPA regulations and guidance. EPA also occasionally travels to an outbreak location, at State request, and performs an engineering study to assess whether the outbreak is indeed waterborne, and what treatment and/or operational deficiencies may have contributed to the outbreak.