Reference marine biological samples are necessary to test the performance o
f the analytical methods employed in surveying and monitoring radioactive m
aterials in the sea. The measurement of artificial and natural radionuclide
activity concentrations in ocean shellfish material by nondestructive ultr
a low-level gamma-ray spectrometry in an underground laboratory is reported
. The material analysed, a composite material made of Irish Sea and White S
ea mussel and Japan Sea oyster, was prepared by the National Institute of S
tandards and Technology (NIST). (C) 2000 Elsevier Science Ltd. All rights r
eserved.