A Fish Story
BY TIM CONNOR
Thirty-nine years ago an accident occurred at the so-called "R"
reactor at the Savannah River Site near Aiken. During a test in the
reactor's water-filled fuel "disassembly" basin an experimental nuclear
fuel rod failed, releasing its intensely radioactive contents.
The contaminated water was flushed to a second basin, which
overflowed. As a result, highly radioactive water was diverted into one of
the many streams near SRS that eventually drain into the Savannah River.
As accidents go, this was no Chernobyl. It was, however, the first of
several large releases of a particularly nasty radioactive substance known
as Cesium-137 into Savannah River tributaries. Before the releases were
brought under control in the early 1970s, a reported 600 curies of Cs-137
were discharged into these streams.
Although significant releases of Cs-137 ended in 1972, the
contamination resulting from earlier releases is considerable. A 1987
Department of Energy (DOE) environmental review found that one of the site
streams, where it reaches the river, was so contaminated that by simply
being present there year round a person would receive radiation exceeding
DOE's guidelines for public exposures.
The fact that SRS' nuclear facilities released large amounts of Cs-137
and other radioactive materials during the bomb plant's Cold War heyday is
by no means news. What is news is that on May 14 the state of South
Carolina, backed by the U.S. Environmental Protection Agency (EPA),
declared a fish consumption advisory for a stretch of the Savannah River
from just above the site to the Webb Wildlife Center in Hampton County.
The advisory was based on measured levels of Cs-137 and Strontium-90
(another radioactive substance largely attributable to SRS releases) in
nine types of Savannah River fish.
Although the advisory issued by DHEC may have startled more than a few
people who fish there, the reality is that fish in the Savannah River are
actually less contaminated today than they were a quarter century ago.
Therein lies a story that reveals as much about the spread of radioactive
contamination from South Carolina's nuclear sacred cow as it does about
the peculiar way government works when agencies with cross-purposes
collide.
Cs-137 is created exclusively by splitting larger atoms in nuclear
reactors or in nuclear explosions. In recent history it has been the main
culprit in two nightmarish nuclear accidents. The first was in Chernobyl,
where the nuclear inferno broadcast millions of curies of Cs-137 across
Europe. The radioactive cesium in the fallout rendered livestock and
foodstuffs from Scandinavia to Turkey unfit for human consumption for
years following the 1986 accident.
The second was a bizarre episode in Goiania, Brazil, the following
year in which scavengers removed a Cs-137-laden capsule from an abandoned
cancer therapy machine. A scrapyard worker later opened the capsule.
Fascinated by the glowing blue powder, he took it home and started giving
it to friends as a novelty item. Before local physicians realized it, more
than 240 people were seriously irradiated
many
severely
and four
were dying.
To be sure, the levels of Cs-137 near SRS are nowhere near those
associated with Chernobyl or Goiania. Largemouth bass from the Savannah
River do not glow blue, and the DHEC fish advisory says that you would
have to have an extraordinary fondness for fish caught downstream of SRS
to even slightly increase your chances of getting cancer.
Perhaps the most important public health message of the fish advisory
is that it reminds us just how vulnerable the Savannah River is to
radioactive and chemical releases at SRS. This is especially true for
Cs-137. The reason radioactive cesium was in the capsule lifted from the
cancer therapy machine in Goiania is that it is both fiercely radioactive
and, with a half-life of 30 years, fairly long-lived relative to most
other "fission" products created when heavy atoms like uranium and
plutonium are split in reactors or bomb blasts.
It also turns out that water in the Savannah River and its tributaries
are low in potassium content, which matters because cesium is chemically
similar to potassium and tends to replace potassium in animal flesh. This
phenomenon is especially important for predator fish like bass, which are
at the top of the aquatic food chain. Bass in waters on and near SRS are
so effective in absorbing Cs-137 that SRS scientists use measurements of
Cs-137 in Savannah River bass to adjust their calculations of Cs-137
releases to the river.
Still, the timing of DHEC's fish advisory is baffling. Cesium
discharges from SRS facilities are a mere fraction of what they were a
quarter century ago and, overall, the measured levels of radiation in fish
at and downstream from SRS have been gradually declining, not increasing.
Moreover, the measurements of the relatively high radiation levels in
Savannah River fish have been gathered and published for well over two
decades.
So, what gives?
The official explanation from DHEC is that the fish data had, for the
first time, been analyzed using "a more comprehensive data risk analysis."
For one thing, in addition to Cs-137, DHEC and EPA addressed the elevated
levels of strontium-90, another dangerous fission product chemically
similar to calcium and thus concentrated in fish bones. Although doses
from Cs-137 in fish flesh are greater than those from Sr-90 in fish bones,
if the whole fish is used in a soup, for example, then the Sr-90 could be
consumed along with the Cs-137 and add significantly to the dose.
But the real story is not the new analysis so much as who got to
conduct it and interpret the results. Since SRS began operations in 1954,
the safety of its releases has ultimately been determined by officials at
the Atomic Energy Commission
now DOE
using
standards that can generously be described as a compromise between public
protection and what the emerging nuclear industry could afford to meet.
Although these standards have gradually been tightened over the years, the
essence of the compromise remains.
For more than a generation, SRS officials have told citizens of South
Carolina and Georgia that the water, air, fish and anything else leaving
the SRS boundary was certifiably safe
defined by
DOE standards.
The DHEC fish advisory is the most visible sign to date that state and
EPA regulators have begun to hold the 42-year-old bomb plant to a
different set of radiation protection standards. The main impetus for this
change came in late 1989, when SRS was officially included on the priority
list for the federal Superfund cleanup program. The designation required
an agreement with EPA and DHEC laying out each agency's jurisdiction over
both the rules and timeline for cleanup of chemical and radioactive wastes
at SRS.
With the change in jurisdiction came the change in standards,
particularly the human-risk-based standards that EPA promulgates under its
Superfund jurisdiction. Whereas DOE radiation standards are based on
allowable radiation doses, EPA looks at health risks. In this instance,
the risk assessed was the increased lifetime cancer risk of people who
rely heavily on Savannah River fish as a food source.
EPA and DHEC say that when the calculated lifetime cancer risks to
individuals fall between a one-in-a-million to a one-in-10,000 chance of
getting cancer as a direct result of exposure, the agency should consider
advisories to alert those thought to be at risk.
The risk calculated by DHEC and EPA risk assessors for consumption of
Savannah River fish was approximately one in 100,000. DHEC's Harry Mathis
said, "It was a borderline call as to whether we advise the public or do
nothing. We decided to err on the side of safety."
EPA's Camilla Bond Warren, who oversees SRS cleanup activities from
the agency's regional office in Atlanta, characterized the action in
broader terms. She said that by using EPA's health risk standards, they
could account for an off-site risk that previously had not been
acknowledged by DOE.
It is notable that even though there are important differences on the
proper inputs to use in the EPA risk model, there appears to be agreement
among EPA, DHEC and SRS technical staff on one key point. Using EPA's
methodology, Tim Jannik of Westinghouse Savannah River Company said, "We
cannot say that the [calculated] risk is wrong even within the differences
of the input parameters."
More notable, however, is that SRS' view that the fish advisory
overstates the current danger is shared by the two Georgia Department of
Natural Resources (GDNR) officials who serve on the interagency team that
examines radiation in Savannah River fish
a team that
exists largely because of long-standing concerns the Georgia agency has
expressed about getting a better handle on the potential hazards of
radiation in Savannah River fish.
Although GDNR officially supports the DHEC advisory, the agency's
technical staff has misgivings about it. "By our methodology," said Jim
Hardeman, manager of GDNR's environmental radiation program, "this just
doesn't come up to the bar [for issuing an advisory]."
In addition to questioning the technical basis for the advisory,
Hardeman poses an inescapable philosophical question. The conservative
formula used by EPA and DHEC is geared toward the protection of
"subsistence" fishermen whose catch of Savannah River fish is necessary
for survival. Those relying on the fish are assumed to consume more than
100 pounds a year for 30 years. This consumption puts them into the
one-in-100,000 lifetime cancer risk range.
The dilemma, Hardeman said, is whether to tell someone whose survival
depends on eating these fish that they should consider changing their diet
because of the extremely remote possibility they may contract cancer as a
result of their eating habits. Surprisingly, none of the agencies has ever
tried to determine if, or how many, subsistence fishermen actually live in
the area covered by the fish advisory.
Moreover, it is by no means clear that eating Savannah River fish
poses the greatest radiation hazard. For example, environmental monitoring
results indicate that the cancer risks posed by eating deer in eastern
South Carolina
many of
which have Cs-137 in their flesh from SRS and fallout from atmospheric
nuclear weapons testing
is
potentially greater than that from eating Savannah River fish.
Another example is the risk from atmospheric and water-borne releases
of radioactive tritium from SRS
releases
that SRS has long acknowledged to be responsible for the majority of the
total population dose resulting from its operations.
In its press release announcing the fish advisory, DHEC stated that
the safety of drinking water is not affected. Yet, as Mathis conceded,
neither of the regulating agencies has actually performed the risk
analysis to support that conclusion
despite the
fact that SRS tritium is readily measurable in downstream drinking water
supplies and flows into the river from the same streams as the Cs-137.
Mathis said the fish advisory will be added to an existing health
advisory about elevated mercury levels in Savannah River fish. The next
step, he said, is to learn more about actual fish consumption patterns on
the river and devise a plan for circulating the revised advisory to those
most likely to be affected.
Tim Connor is associate director of the Energy Research
Foundation.
The timing of DHEC's fish advisory last month is baffling. The measurements of the relatively high radiation levels in Savannah River fish have been gathered and published for well over two decades. So, what gives?
