Brookhaven National Laboratory


June 11, 1997

June 11 Update on Groundwater Contamination
Near Underground Collection Tank

Test results show that strontium-90 is the only radioactive element besides tritium that is present in groundwater immediately south of an underground collection tank at the U.S. Department of Energy's Brookhaven National Laboratory. The findings are consistent with earlier test results,
released March 27, that showed signs of radioactive substances other than tritium.

Strontium was found in water samples taken from 13 temporary monitoring wells installed in the area 45 feet south of the underground tank. The peak strontium concentration is 566 picocuries per liter (pCi/L). The U.S. Environmental Protection Agency's drinking water standard for strontium is 8 pCi/L.

As reported in March, tritium is present in groundwater south of the tank at levels as high as 6,900 pCi/L, approximately one-third the EPA tritium drinking water standard of 20,000 pCi/L.
None of the contamination has impacted on-site drinking water wells.

Strontium travels relatively slowly in groundwater, about 25 feet per year. The tank is 1.5 miles north of the BNL site boundary. BNL is now preparing to install additional temporary monitoring wells further south of the tank to assess the extent of the contamination. Strontium-90 analysis takes roughly two months.

Contamination originating from the tank will be remediated under the BNL Superfund program, which added the tank to its remediation list in December 1996. The collection tank was built to collect drainage from pipes connected to the base of the High Flux Beam Reactor (HFBR) stack and the fan house for the former Brookhaven Graphite Research Reactor, which was shut down in 1968.

The tank may have leaked from a non-watertight seal between a stainless steel duct and one of its concrete walls. The seal is located above the tank's intended water level, but there are indications that water in the tank rose above the seal level.

Approximately 750 gallons of water were removed from the concrete-walled tank on March 12, after an analysis of the water in the tank showed high levels of tritium and radioactive strontium-90, radium-226 and cesium-137. Because the tank is now empty, there is no continuing source of contamination. BNL has taken steps to monitor the tank and to ensure that water does not accumulate in it.

In order to find or prevent any other instances of groundwater contamination from operating or unused Lab facilities, BNL initiated a sitewide review of all facilities in April. The U.S. Department of Energy and the Suffolk County Department of Health Services are also participating in the review; findings will be released as they become available.

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