Drinking Water Standards vs. Public Health Goals

1
Drinking Water Standards vs.Public Health
Goals

• Donald R. Kendall, Ph.D., P.E.
• General Manager
• Calleguas MWD
• June 13, 2001

2
Until 1996, regulatory information about safe
levels of chemicals in drinking water was
straightforward

• Maximum Contaminant Levels were established for
  various chemicals, and water could not be
  provided to consumers if those levels were
  exceeded.

3
What are MCLs?

• Maximum Contaminant Levels are primary drinking
  water standards for contaminants in drinking
  water established by the California Department of
  Health Services (DHS).
• Set to avoid any known or anticipated adverse
  effects on public health with an adequate margin
  of safety.
• Enforceable by the State.
• Never less stringent than the USEPAs National
  Primary Drinking Water Standards.

4
History of Public Health Goals

• In 1989 introduced as Recommended Public Health
  Levels, AB 21 (Sher), requiring
• consideration of health effects only for setting
  of drinking water standards,
• no consideration for technical achievability or
  laboratory detection limits, and
• separate monitoring programs be developed for
  different State agencies (increased monitoring
  and reporting costs).
• In 1996 SB 1307 (Calderon/Sher) was adopted as a
  compromise, modifying AB 21.

5
Why?
6
What are PHGs?

• Public Health Goals are health protective "goals"
  to be considered relative to MCLs that may be
  revised or established.
• Intended to provide estimates of levels of
  chemical contaminants in drinking water that
  would pose no significant risks, including
  sensitive subpopulations, over an entire
  lifetime.
• Not drinking water standards.
• Not enforceable.
• Unique to California.

7
Who Sets PHGs?

• California Environmental Protection Agency,
  Office of Environmental Health and Hazard
  Assessment (OEHHA)

8
How are PHGs Set?

• PHGs must be set for all contaminants for which
  MCLs have been set or are anticipated.
• Reviewed revised at least once every 5 years
  based upon the availability of new scientific
  data.

9
Adoption of PHGs

• A total of 53 PHGs have been adopted to date.
• 25 in 1997
• 21 in 1999
• 6 in 2000
• 1 in 2001 (to date)
• There are 24 contaminants with State MCLs for
  which no PHG exists.

10
Upcoming PHGs

• PHGs are proposed for the following contaminants
• Benzene (0.14 mg/L)
• Nickel (1 mg/L)
• Simazine (0.4 mg/L)
• Tetrachloroethylene (0.056 mg/L)
• Uranium (0.2 pCi/L)

11
What is required of water utilities?

• Every 3 years, report the detection of
  contaminants that exceed the PHG.
• Report also must contain treatment costs
• Next report due July 1, 2001
• Hold public hearings to accept and respond to
  public comment on the report.
• Include PHGs in the annual report to customers
  (Consumer Confidence Report).

12
PHGs vs. MCLs

• PHGs are concentrations of contaminants in
  drinking water set by OEHHA based solely on a
  health risk assessment. They are not enforceable
  standards.
• MCLs are enforceable drinking water standards set
  by DHS based on a health risk assessment,
  occurrence, analytical detection limits, and
  available treatment technology.

13
Comparison of PHGs MCLs

• 18 PHGs are the same as the MCL
• 23 PHGs are below the MCL
• Of those, 16 PHGs are at levels below modern
  laboratory detection limits
• 12 PHGs are above the MCL
• When two different agencies review available
  health risk information, they often arrive at
  different conclusions.

14
PHGs and Public Perception
15
PHGs have created incorrect public perceptions

• People understandably have difficulty reconciling
  two different levels of safety published for a
  single chemical.
• Water agencies are legally required to comply
  with MCLs but may be subjected to public pressure
  related to PHGs.
• People incorrectly perceive significant risk from
  chemicals in drinking water. (According to
  toxicity tests used to establish drinking water
  standards, a potato is a carcinogen because it
  produces natural pesticides.)

16
Chromium Many health effects studies have been
done on chromium, both on humans in and around
manufacturing facilities and on animals in
laboratories. Federal and State agencies
differ in opinion as to the carcinogenicity of
chromium 6. National Institute of Science
Health, USEPA, and the California DHS do not
consider chromium 6 a carcinogen when ingested.
California OEHHA does, but they acknowledge
that their conclusion is based on a suspect
study, and are reviewing available studies to
verify their position.
17
Regional Chromium Issues

• OEHHA has established a health protective level
  for chromium 6 at 0.2 micrograms/L.
• Findings in the L.A. area have been over 100
  micrograms/L in some wells.
• Recent sampling has shown concentrations in
  Calleguas water to be 0.03 to 0.15 micrograms/L.

18
Chromium in water

• Two forms chromium 3 chromium 6
• Soluble forms of chromium 6 include those
  containing sodium potassium.
• Insoluble forms include those containing barium,
  calcium, strontium, zinc lead.

19
Sources of Chromium

• Natural
• Erosion of chromium ores
• May be related to geothermal activity - possible
  correlation between presence of chromium
  presence of arsenic radon
• Man made
• Chrome plating (also produces TCE nickel)
• Corrosion control (Hinckley)
• Stainless steel manufacture
• Pigment production

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PHGs are a disservice to the public

• Conflicting safe levels determined by two
  different State agencies have unnecessarily
  confused and alarmed the general public.
• The PHG for chromium was based on a single mouse
  study evaluated with bad science.
• Clean-up legislation is needed to resolve these
  problems.
• PHGs represent a gift of public funds.