Monday, September 25, 2000

FRENCH FRIGATE SHOAL SEDIMENTS TO BE ANALYZED FOR TOXIC CONTAMINANTS

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Today, scientists, Donna Turgeon (above) and Michelle Harmon, aboard the expedition vessel Rapture, boarded a zodiac bound for the inner regions of French Frigate Shoals. Their research leads them to these lagoon waters to collect sediment samples to analyze for possible post-military toxic contaminants and small animals and invertebrates that inhabit the top layers of the sand. 

The team aims to look for and classify the living organisms in the sand bottom, something that is not usually looked at by coral scientists but is
a vital part of the ecosystem. The data they collect will serve as a baseline for comparison with future studies as their work is the first of
its kind at French Frigate Shoals.

According to Turgeon, marine ecologist from NOAA's National Ocean Service, "We have more than 15 years of data on toxic contaminants from around the continental United States, the Caribbean, and even international coastal areas, but this will be the first data we collect from the Northwestern Hawaiian Archipelago.

"We are looking forward to perhaps finding some answers as to where marine mammals with high tissue levels of polychlorinated biphenyls (PCBs) may have been exposed to such organic contaminants in the region," explained Turgeon.

PCBs are organic compounds that are known carcinogens. They have been found in significant levels in marine mammals, like monk seals, from the region. Turgeon will focus her search for PCBs and other toxic chemicals in areas that have a previous military history including French Frigate Shoals, Midway and Kure.

When PCBs are found in marine mammals at remote areas that the military once occupied, it usually indicates that contaminants are still present in the ocean floor. If the sediment team finds unusually high levels of PCB's the samples they collect, their data will be shared and reported to the State of Hawaii, which in turn must report the findings the Environmental Protection Agency (EPA). Depending on the data, the EPA could call for a more intense monitoring of the area, or, if the levels of contamination are significant enough, the agency could declare the Shoals a 'Super Fund Site' and call for an immediate clean up.

In addition to looking for PCB's, the team will collect fine sediment samples and send them to specialized laboratories for chemical analyses.
They will also verify, or 'ground-truth,' information captured on satellite imagery, taken by IKONOS satellite, to ensure that the information provided in the imagery matches what is found during scientific observation. By observing different bottom types, the team will compare their data with the satellite pictures images to confirm or dispute them. In the case of a dispute, scientists will correct the images and create more accurate maps.

The team's field study at French Frigate Shoals began yesterday, and included a visual reconnaissance of the southeast and easternmost part of the lagoon. They traversed 4 miles of reef, stopping at regular intervals to record depth, bottom habitat type, and to collect sediment samples. They found that this part of the lagoon is made up of coarse sand and coral rubble and contained no fine sediments needed for toxicant analysis.

Over the next few days, the team will move northward along the seaward edge of the atoll. In addition, fellow divers involved with coral and fish
research will assist them by collecting sediment samples along the transect lines they are studying.


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