The present Reference Method is designed to provide a set of guidelines to assist in pollution and public health to design and implement monitoring programmes based upon the measurement of chemical contaminants in marine biota. It is strongly recommended as essential reading material prior to organizing a monitoring programme. It forms the basis of the strategy currently employed by UNEP's Regional Seas Programme, the GIPME programme (Global Investigations of Marine Pollution, jointly sponsored by IOC and UNEP) and of several programmes organized by FAO (particularly in their contribution to the MEDPOL programme).