Definitions of monitoring activities and their relevance for the practice of occupational health.

The authors discuss the definitions of environmental monitoring (EM), biological monitoring (BM) and health surveillance (HS) as agreed upon by a CEC/NIOSH/OSHA-seminar in 1980. They emphasize the essential differences in underlying principles. They add a fourth definition of biological effect monitoring (BEM). Each method has its own assets and liabilities. Moreover, EM and BM require another decision-making process (situation-centered) then BEM and HS (client-entered) of measures to be taken. When the differences between the four approaches are not taken into account, valid preventive measures may be hampered.