U.S. Public Health Service Capt. Walter Watkins turned the Beaufort River red and his fingers pink Monday, all in an attempt to find out where it is safe to harvest shellfish.
As part of the U.S. Food and Drug Administration's Shellfish Safety Team, Watkins injected two large containers of red dye into treated wastewater discharged into the river near the Port Royal Marina.
"We're trying to figure out where the wastewater goes, how far does it travel and how much does it dilute," he explained.
Bright red when concentrated, the dye becomes less noticeable as it is dispersed by waves and currents. Testing will continue through today.
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A rusty streak a few hundred yards long was visible in the river Monday afternoon from the J.E. McTeer Bridge between Port Royal and Lady's Island. The dye only stains skin and clothing when it is concentrated enough to be seen.
Long after the dye becomes invisible to the human eye, sensors in the water continue to track its path.
"The dye allows us to see exactly how it flows and where exactly it flows during different tidal levels," said Adam Myrick, spokesman for the S.C. Department of Health and Environmental Control.
The data tell researchers which areas are safe for harvesting shellfish and which could be contaminated if there is a problem with the wastewater.
"When eating raw oysters, it's like any raw protein, like raw milk or raw eggs. There's always a higher risk," Watkins said.
He was optimistic the tests would indicate harvesting could be allowed in some upstream areas where it is prohibited. Wastewater treatment has significantly improved over the years, Watkins said.
The researchers are most concerned about fecal matter and viruses in the wastewater, Watkins said. While bacteria dies in a few days, viruses can live for several weeks, he said.
The last dye study on the Beaufort River was in the 1980s, according to DHEC.
Shellfish harvesting season begins Saturday, but Myrick said he doubts the study's findings will affect fishing this season.