The significance of neurobehavioral tests for occupational exposure limits: an example from Sweden.

The setting of OELs is part of risk management. It should, however, be kept in mind that not only scientific data affects the outcome of an OEL but also cost-benefit and technical feasibility. During the last decades, neurobehavioral methods have been used increasingly in human studies to investigate the effects of neurotoxic chemicals on the nervous system. Since exposure levels in the workplace are becoming lower and lower, traditional epidemiology will face difficulties in revealing any effects. Therefore authorities regulating chemicals must rely more and more on toxicological data and on results from experimental human studies. It will then be crucial that sound criteria for the validity of human neurobehavioral studies of neurotoxicity are established if the results from neurobehavioral studies are to be used in regulatory risk assessment. Because of the variation in individuals response to chemical exposures, exposure limits might not be possible to set with a view toward this range of susceptibility and the avoidance of any neuropathic effects. This paper discuss the Swedish experience when using neurobehavioral data in deciding effects on the nervous system as the critical effect.