Low-level radioactivity ocean sediment standard reference material

The National Institute of Standards and Technology (NIST), in cooperation with experienced international laboratories, will issue a low-level radioactivity Ocean Sediiment Standard Reference Material (SRM) 4357 in 1996. The Ocean Sediment joins the NIST suite of six other ‘natural matrix’ environmental radioactivity Standard Reference Materials. This family of natural matrix materials have already been used: (1) to develop radiochemical procedures; (2) to test radiochemical procedures already in use for environmental and biokinetic evaluations; (3) to calibrate instruments; (4) to intercompare and evaluate radiochemical methods; (5) to test competency of technicians to do radiochemical assays; and (6) to demonstrate that data output is reliable. The participating laboratoires provided data for the radionuclides are of sufficient quality to establish certified values and reanonable uncertainty limits given the relatively low concentrations of the radionuclides. The uncertainties for a number of certified radionuclides are non-symmetrical and large because of the non-normal distribution of reported values.