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water. It can also serve as a reference base to compare any future 

 measurements we or others may make as part of environmental monitoring 

 programs. 



In the area of new research, the LLNL is investigating new 

 cytogenetic methods for observing chromosome changes in marine worms 

 related to various radiation dose levels. These studies are concerned 

 with very low radiation doses that might be associated with ocean 

 disposal of low-level radioactive waste and that are below radiation 

 dose levels at which chromosome changes can be observed by traditional 

 methods. This new technique detects chromosome changes by sister 

 chromatid exchange, and we hope to perfect this technique as a tool for 

 monitoring biological responses to radiation at levels well below those 

 representing any potential harm to marine organisms. Such measurements 

 could supplement normal radiation dose model predictions and perhaps 

 provide another effective monitoring technique. Further studies are 

 needed to evaluate the technique in relation to continuous radiation 

 exposure to marine worms and radiation exposures for radionuclides 

 ingested within the organisms, in contrast to external exposures. 



In addition, the LLNL has been tasked by EPA to provide 

 radionuclide analysis assistance to an international research and 

 environmental surveillance program. This is part of the U.S. 

 contribution to the Nuclear Energy Agency's efforts to monitor the 



