More fish test positive for Sr-90, but not due to Vermont Yankee

first_imgNew fish samples taken from the Connecticut River on April 23 and analyzed by Vermont Yankee’s contract laboratory have tested positive for strontium-90 (Sr-90). Concentrations of Sr-90 detected in the inedible portions of these fish are in the range of what would be expected as a result of fallout from nuclear weapons testing in the 1950s, and the Chernobyl release in 1986.Specifically, the laboratory results for Sr-90 were 70 pCi/kg from fish taken near the plant in the Vernon Pool, and 100 pCi/kg from fish taken about 5 miles upstream, near the Route 9 bridge as it crosses the river north of Brattleboro. A New York study found background levels of Sr-90 in fish to be in the range of 120 to 360 pCi/kg (see New York Fish Study below).Vermont Yankee reported these latest test results to the Health Department on June 30. The first samples of fish to be analyzed were taken in February 2010 from the same locations, and these fish also tested positive for Sr-90. In both cases, concentrations are within the expected range. Sr-90 has not been detected in edible parts of the fish. Like calcium, strontium accumulates almost entirely in bone.Because the Sr-90 results are all within what is considered to be the normal “background” range, and because no Sr-90 has been measured above the lower limit of detection in groundwater on site at the plant, the Health Department considers it unlikely that these findings in fish are a result of recent events at Vermont Yankee.Fish caught from the Connecticut River are among the many samples being analyzed for radioactive materials by the Vermont Department of Health, Vermont Yankee, and by contract laboratories employed by both.So far, soil samples analyzed by the Health Department’s contract laboratory for hard-to-detect radionuclides are the only samples to be positive for Sr-90, or for any other radioactive materials, that can associated with Vermont Yankee operations. Should other radioactive materials such as cobalt-60 or cesium-137 be detected in groundwater or fish, this would be evidence that the strontium in fish was strontium from Vermont Yankee.To date only tritium, which moves easily through the soil as tritiated water, has been detected in groundwater samples, and only in groundwater on site at Vermont Yankee. No drinking water on site or off site, nor any river water has been found to be contaminated with tritium above the laboratory’s lower limit of detection.New York Fish StudyThe amount of Sr-90 in fish as a result of nuclear weapons testing and Chernobyl is in the range of 120 to 360 pCi/kg, according to a study published by the New York Department of Environmental Conservation in November 2009: is external)   (exit VDH)The New York study results were published after radioactive materials leaked from the Indian Point nuclear power station on the lower Hudson River. These levels, presumed to be background, are based on Sr-90 results from more than 150 fish caught about 70 miles north and upstream from the Indian Point plant.Groundwater ExtractionVermont Yankee officials have indicated that another extraction well will be in operation soon. This will be either be a new extraction well, or modification of an existing monitoring well such as GZ-15, which is located in the area of the plume that now has the highest tritium concentration. Vermont Yankee has set a goal of pumping out 300,000 gallons of tritium-contaminated groundwater. The original extraction well has so far pumped out about half that volume, and tritium concentrations in groundwater still being pumped from the original extraction well are now approaching the lower limit of detection.Monitoring Well Test Results – as of July 2, 2010For the first time, groundwater samples from well GZ-20, which is located near the condensate storage tank and northeast of the Advanced Off-Gas (AOG) pipe tunnel and drain line, are showing measurements for tritium below the lower limit of detection (This means that GZ-20, along with other wells no longer located within the plume of contamination from the AOG leak, can now serve to detect any new leaks that may occur. At the height of the AOG leak investigation, as many as 12 groundwater monitoring wells were showing tritium contamination. This week, only seven wells are showing tritium contamination above the level of detection, and only three of them–all located next to the Connecticut River–have increasing tritium concentrations. The other wells that are still contaminated have decreasing tritium concentrations. The results that follow are as reported by Vermont Yankee for tritium. To date, gamma spectroscopy and special analyses for hard to detect radionuclides have not identified any other nuclear power plant related radioactive materials in groundwater, drinking water or river water. Note that well GZ-6 which had not been sampled for about 6 weeks, is back on a weekly sampling schedule.All results are expressed in terms of picocuries per liter (pCi/l), or below the lower level of detection (GZ-1: Source: Vermont Health Department. 7.2.2010last_img

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