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Industry Passes Eco Test in Cook Inlet

'Clean Bill of Health'

What if you offered a presentation on potential pollution caused by oil and gas companies -- and nobody came?

This 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

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 Shelikof Strait.

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What if you offered a presentation on potential pollution caused by oil and gas companies -- and nobody came?

This 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

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 Shelikof Strait.

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 metals.

"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.

Results

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 exploration companies.

Either way, Prentki added, the oil and gas industry "was given a clean bill of health."

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