Water Quality

Tuesday, October 4, 2016

Recently a web blog was published that contained a few factual errors regarding Hexavalent Chromium in our source water.  While the actual levels were cited off the official web site the terminology Public Health Goals and Maximum Contaminant Levels have two completely different meanings.  Please see the information provided to discern the difference.

  1.  California Public Health Goals.  The California Safe Drinking Water Act of 1996 requires the Cal/EPA, Office of Environmental Health Hazard Assessment (OEHHA) to perform risk assessments and to adopt Public Health Goals (PHGs) for contaminants in drinking water based exclusively on public health considerations.  PHGs are not regulatory standards.  PHGs represent levels of contaminants in drinking water that would pose no significant health risk to individuals consuming the water on a daily basis over a lifetime, based on current risk assessment principles, practices, and methods.  For a carcinogen, OEHHA typically establishes the PHG based on a “one-in-a-million” cancer risk level.  OEHHA and the California State Water Resources Control Board, Division of Drinking Water (SWRCB, DDW) consider the “one-in-a-million” risk level to represent a de minimis level of cancer risk for involuntary exposure to contaminants in drinking water.  OEHHA is required to review adopted PHGs at least once every five years and revise as necessary based on the availability of new scientific data.
  2. California Public Health Goals versus State Primary Drinking Water Standards.  PHGs adopted by OEHHA are developed for use by the SWRCB, DDW in establishing and updating primary drinking water standards (State Maximum Contaminant Levels, or MCLs).  MCLs are adopted as regulations that set health protective drinking water standards to be met by public water systems.  Where PHGs are to be based solely on scientific and public health considerations, drinking water MCLs take into account not only health risk but also consider technical feasibility such as detectability and treatability and economic factors such as treatment cost.  Each MCL adopted by SWRCB, DDW is to be set at a level that is as close as feasible to the corresponding PHG, placing emphasis on the protection of public health.

California Water Board issued a Chromium Fact Sheet that provides specific details regarding this important issue!