CALIFORNIA HEALTH RISK ASSESSORS PROPOSE A PUBLIC HEALTH GOAL FOR ARSENIC OF
FOUR PARTS PER TRILLION
The California EPA’s Office of Environmental Health Hazard Assessment
(OEHHA) today released their draft PHG for arsenic which is proposed
at 4 ppt (or 0.004 parts per billion). It is set (technically, it
is "prepared
and published")
based exclusively on public health considerations without any weight
given to practical factors such as laboratory capability to analyze,
availability of treatment systems, or costs. The Drinking Water Division
of the California
Department
of Health Services is charged with establishing a legally enforceable
MCL that is as close to the PHG as is "technologically and economically" feasible.
Even though California is required to adopt an MCL at least as stringent as
the USEPA’s
10 ppb MCL and do it by 2006, the California Legislature passed a law
that requires the state MCL be adopted by July 1, 2004. It is not expected
that
utilities will be required to come into compliance with the new California
MCL earlier than the federal regulation. (That law had required the PHG
to be set by December 31, 2002. Publication of the draft PHG sets in
motion a
45-day review period and a public workshop before it can be finalized.)
Under California law, the PHG is somewhat parallel to the USEPA’s MCLG.
However, for carcinogens such as arsenic, EPA is required to set the MCLG at
ZERO. For various reasons, the fact that OEHHA never sets their PHGs at zero
but does theoretical risk calculations to come up with a very small but finite
number somehow gives that number a greater significance in the eyes of the
media, environmental activist groups and subsequently the general public.
OEHHA’s PHG for arsenic was set based on a theoretical one-in-a-million
risk of cancer based on epidemiological studies from China, Argentina
and Chile. Like USEPA, OEHHA gave little credence to an epidemiological
study from Utah which showed
significantly lower cancer risk. The National Academy of Science’s
arsenic review and guidelines were relied upon heavily. OEHHA's risk assessment
was peer-reviewed by scientists in the University of California
system.
CDHS is in the process of completing a series of stakeholders meetings getting
input from the public on the arsenic standard-setting. The California
legislation mandating the state arsenic MCL specifically requires the department
to consider "emerging
technologies that may cost-effectively reduce exposure to arsenic in
drinking water." Advocacy organizations are pressing DHS to set the MCL
at 2 ppb.
The analytical detection level for arsenic in drinking water set by the state
as the DLR (Detection Level for purposes of Reporting) is 2 ppb.
