Five Isotopes Found in Pilgrim Water Samples

By Christine Legere May 24, 2023

PLYMOUTH — Five radioactive isotopes and 22 nonradioactive pollutants were found in untreated wastewater samples drawn from the spent fuel pool, torus, and dryer-separator at the closed Pilgrim nuclear power plant last month.

The Dept. of Public Health and Dept. of Environmental Protection released their analyses at the May 22 meeting of the Nuclear Decommissioning Citizens Advisory Panel (NDCAP). There were no surprises in the results, the state agencies said.

The testing of the untreated wastewater was done to ensure the validity of testing being done by Holtec Decommissioning International, the company that now owns the Plymouth plant.

Holtec proposes to release 1.1 million gallons of radioactive wastewater into Cape Cod Bay. That plan is opposed by legislators at all levels of government, environmental groups, the seafood and tourist industries, and the general public. The company has applied to the state DEP and federal Environmental Protection Agency for a wastewater discharge permit needed for the release.

In its analysis of the samples taken in April, DPH found five radioactive isotopes above the detection limit: manganese-54, cobalt-60, zinc-65, cesium-137, and tritium.

Other than tritium, those elements would be reduced by a treatment system to levels allowed by the federal Nuclear Regulatory Commission, the DPH said in a conference call with reporters on Monday. Concentrations of tritium, an isotope that can't be reduced by treatment, would be lowered by dilution.

The water would be released in batches of 18,500 gallons of wastewater mixed with nearly one million gallons of salt water from the bay.

Among the 239 nonradiological pollutants that were tested for, 22 were present at concentrations above the detection limit. They included nine PFAS compounds, one semivolatile organic and two volatile organic compounds, eight metals (boron, cobalt, copper, iron, nickel, potassium, zinc, and cyanide) and five general chemistry measures (nitrogen/nitrate, oil and grease, pH, total dissolved solids, and chlorine). The analysis of the nonradiological pollutants was done by Gel Lab in South Carolina.

If the DEP and EPA ultimately grant Holtec a discharge permit, any wastewater released would first undergo treatment to remove or significantly reduce the pollutants to levels allowed in the permit, said Gerard Martin, the DEP's regional director of the Bureau of Waste Site Cleanup during the May 22 NDCAP meeting.

There is no guarantee at this point that the permit will be issued, he said.

"The application requires several state and federal permits and reviews," Martin said. "The comments and concerns raised by the NDCAP and the public will be carefully considered in the state's actions. The Healey-Driscoll administration also has serious concerns about the proposed discharge of decommissioning wastewater into the bay."

Concerns of a Scientist

Ken Buesseler, a marine radiochemist at the Woods Hole Oceanographic Institution, reviewed the results on Tuesday and said the radionuclide levels were high, even factoring in that the wastewater was untreated.

The report used very concentrated unit measurements for radioactivity found in a very small amount of water. "The result might read .003, but that's actually quite a lot of radioactivity compared to what's in the ocean," Buesseler said. "The numbers for cesium-137 in the untreated water are 200 million times higher than what's in the ocean right now."

Tritium is often a source of concern because it can't be cleaned out of the water, but the other radionuclides that were found have greater health effects, he said.

Cobalt ends up in seafloor sediments and can be ingested by marine life and end up in humans who eat the seafood, Buesseler said.

Based on what he has seen at Japan's Fukushima, the million gallons at Pilgrim will require a sophisticated cleaning system and probably more than one treatment, he said: "It's got to go through it again and again and again. Even if you remove 99 percent of it, you might still be a million times higher than what's in the ocean.

"They need to demonstrate they can get more than 99 percent removal, and that's not easy," he added. "And it's different for different radionuclides." According to Buesseler, the water will never be 100 percent clean.

Further tests would be needed to determine levels of other radioisotopes such as carbon-14 and strontium-90, plutonium, and uranium, which require more advanced testing. "Once you see these other isotopes at these levels, you know there's other forms of radioactivity than just the five radionuclides," he said.

The best solution for the wastewater, according to Buesseler, is to store it onsite for 50 years or so after it is treated.

New Study Is Announced

At the NDCAP meeting, Matthew Charette, a senior scientist at Woods Hole Oceanographic Institution and director of its Sea Grant program, outlined a study of the currents in Cape Cod Bay that WHOI scientists will conduct starting in July.

"I’m sure everyone here appreciates the fact that the bay hosts a diverse and productive marine ecosystem, and that it's the site of many commercial and recreational fishing and aquaculture enterprises as well as a thriving tourist economy," Charette said. "All of these aspects of the blue economy depend critically on water quality in the bay."

The study will provide regulators with information about where the surface water travels and how long the water stays in the bay, building on a study done last year by WHOI oceanographer Irina Rypina.

Rypina's study, based on data collected by 400 drifter buoys, concluded the wastewater released from the Pilgrim plant would flow southward and split into two branches. One would flow into the bay, where it would slowly circulate for about two weeks; the other would flow past Race Point in Provincetown and head southward on the ocean side of the Outer Cape, hugging the coastline.

A possible pathway showed the release heading north toward Duxbury, then turning south and flowing into the bay.

The new study will add temporal variabilities, such as tides, wind, and the seasons, to the analysis, providing a clearer picture of water's potential presence in aquaculture areas.

NDCAP member Andrew Gottlieb said the results of the study would be valuable in understanding the flow within the bay but "were largely irrelevant" to those making regulatory decisions on wastewater discharge permits.

"The plain reading of the law says no discharge," said Gottlieb, executive director of the Association to Preserve Cape Cod.

"These results shouldn't be determinative, nor should the agencies feel the need to wait for this work to be completed to reject the application," Gottlieb said.

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Tagged With: Holtec, Pilgrim nuclear power plant Filed Under: Environment, Featured, News