WASHINGTON — A team of scientists will set out Saturday from Hawaii on a research expedition to study how radioactive contamination from the nuclear power plant crisis in Japan has spread in the Pacific Ocean and what effects it will have on marine life, the food chain and human health.
The scientists say the effects of radioactive contamination in ocean waters, sediments and fish is not well understood. The Japanese nuclear disaster is the worst release of radioactive materials into an ocean.
The contaminated water in the ocean is diluted to much lower levels as it travels from the plant to waters far offshore. Miles from shore, the elevated levels of radiation aren't a direct public health hazard, but there are still many questions about the impact of long-lived isotopes that can accumulate in the food chain and in sediments, according to the Woods Hole Oceanographic Institution, which is leading the trip.
The chief scientist, Ken Buesseler, said it's critical to get observations of radioactive contaminants, or radionuclides, in the water and in marine life.
"Together with measurements of ocean currents, we can begin to understand the potential near- and long-term severity of the releases and related public health issues," he said in a statement.
Nick Fisher of the State University of New York at Stony Brook will lead the team of researchers looking at microscopic plants and animals at the base of the food chain, as well as seaweed, fish and shellfish consumed by people, to determine how much radioactive material they accumulate.
Cleaning up the ocean sediments and other areas near shore would be "enormously expensive and the effectiveness of such actions is very uncertain at this time," he said. There are some cleanup methods that have been used for other pollutants in sediments, but they generally haven't been used for contamination with radioactive materials, he said.
Japanese scientists have been conducting research since soon after the March 11 tsunami and earthquake that damaged the plant. The 15-day expedition on the research vessel Kaimikai-O-Kanoloa is the first major international collaboration. Scientists from the U.S., Japan and Spain will be on board, and they'll work with scientists at labs in the U.S., Europe and Japan.
The runoff into the ocean came from efforts to flush the reactors with water to cool them. Matthew Charette, an associate scientist at Massachusetts-based Woods Hole, said the scientists don't know whether radioactive water continues to flow into the ocean.
The contaminated water now is accumulating in storage containers at the plant. Work is under way on a system to decontaminate the water so that it can be recycled and won't overflow and spill into the ocean again. NHK, Japan's national broadcasting company, reported this week that Tokyo Electric Power Co., the owner of the plant, also plans to plug leaks in seawalls and other places at the plant to prevent more spills.
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