What if you offered a presentation on potential
pollution caused by oil and gas companies -- and nobody came?
was more or less the situation geochemist John Trefry and his colleagues
found themselves in at the conclusion of a two-year study undertaken
by the U.S. Minerals Management Service (MMS) regarding the possible
linkage of contaminants to oil and gas development in Alaska's Cook
Inlet and Shelikof Strait.
"Initially, there was a lot of interest," Trefry
recalled, "but after the first year when we presented the study,
there was no interest.
"When we gave the presentation at the end of the
second year, there were very few people present, for they knew there
was nothing to get excited about."
No news may be boring, but in this case it's good
news for energy companies that are used to receiving bad press regarding
pollution, particularly in the politically sensitive world of Alaska.
This study, titled "Sediment Quality in Depositional Areas of Shelikof
Strait and Outermost Cook Inlet," concluded that "the contaminants
in this area are not linked to oil and gas development in Upper
Cook Inlet or the Exxon Valdez spill."
The study, conducted by Arthur D. Little Inc., which
hired Trefry for the project, took place during 1997 and 1998. It
looked for hydrocarbon and trace metal contaminants from oil industry
activities in areas with fine-grained sediments in Cook Inlet and
Oil industry contaminants will absorb on to fine-grained
material in the water and would be expected to end up where fine-grained
sediments are accumulating.
Samples were taken from the sites in question, with
additional sampling stations in the Gulf of Alaska to provide "upstream"
source material. The study evaluated the amount of petroleum-related
compounds and other metals present in sediment, sediment cores,
fish tissue and source samples.
"We took thousands of samples with sediment cores,
some of which went back a hundred years," says Richard Prentki,
a chemical oceanographer with MSS in Anchorage. The residue found
in those areas, he added, originates from a combination of natural
sources -- river runoff, eroded rock or coal, and natural seeps.
The concentrations in the sediments, resulting from
natural causes, do not pose a significant risk to the environment.
Nor does this residue show any signs of increasing.
Prentki said the samples were compared to those taken
from areas that were known to have bad effects. Samples were taken
from just above and just below the water surface, which revealed
whether it supported living organisms or whether the surface was
oxidized and rendered detrimental.
Enzyme essays also were taken in halibut and other
fish to determine if there were any toxicity levels. Fish were also
examined to see if they had any visible sores.
"One of the interesting things we were able to do
was to determine sediment accumulation rates ranging from a few
tenths of a centimeter to an excess of one centimeter per year,"
said Trefry, speaking as both a geochemist and trace metal chemist.
"We determined that most of the sentiments, about 75 percent, came
from the upper rivers that drained around the Anchorage areas. Most
of the remaining sediment came from the Cooper River.
"What was also interesting is that we were able to
corroborate radioisotope data with ash layers in the sediment from
the eruption of Mount Katmai in 1912," he said. "And we were seeing
that what appeared to be a recent increase in the sediment accumulation
rate may have resulted from deglacialization."
They analyzed sediments for about 19 different trace
"Our basic conclusion," he said, "was that over the
100 years have been very similar in a given core, with no evidence
of pollution from metal inputs."
Trefry, who has been involved in similar studies
in the Gulf of Mexico and Alaska said that "it is the common job
of MMS to make sure that lease pits stay environmentally as clean
as possible." He added that this project was a bit different in
that the sediment was carried 50 to 100 miles away from where it
originated, quite a ways into the strait, before it settled into
the deeper water.
Did Trefry, before he started on the project, think
he would find any pollution?
"I can't say that I've ever found contamination that
has been washed away so far from its source," he said. "It would
have been very difficult to contaminate. I looked at the discharge
in Anchorage, the discharge permitted for the industry and took
what they said they discharged, which could have added a small contribution."
In fact, Prentki said, "We had done prior studies
in the 1970s and early 1990s looking for oil contamination, but
did not find anything both those times."
Moreover, this study's findings are consistent with
those of the recent draft EPA report on contaminant levels in Cook
Inlet subsistence foods. That study also found low levels of oil
industry contaminants and provided additional confirmation.
So why was this $1.5 million study, which involved
the Florida Institute of Technology, University of Alaska at Fairbanks
and Applied Marine Scientists, ever conducted?
Scientists, environmentalists and others thought
the matter should be investigated, he said. Also at issue was the
EPA general discharge permit, which was due to be renewed for the
Either way, Prentki added, the oil and gas industry
"was given a clean bill of health."