Biological monitoring and Biological Limit Values (BLV): the strategy of the European Union

Occupational standards concerning allowable concentrations of chemical compounds in the ambient air of workplaces have been established in several countries worldwide. With the integration of the European Union (EU), there has been a need of establishing harmonised Occupational Exposure Limits (OEL). The European Commission Directive 95/320/EC of 12 July 1995 has given the tasks to a Scientific Committee for Occupational Exposure Limits (SCOEL) to propose, based on scientific data and where appropriate, occupational limit values which may include the 8-h time-weighted average (TWA), short-term limits/excursion limits (STEL) and Biological Limit Values (BLVs). In 2000, the European Union issued a list of 62 chemical substances with Occupational Exposure Limits. Of these, 25 substances received a "skin" notation, indicating that toxicologically significant amounts may be taken up via the skin. For such substances, monitoring of concentrations in ambient air may not be sufficient, and biological monitoring strategies appear of potential importance in the medical surveillance of exposed workers. Recent progress has been made with respect to formulation of a strategy related to health-based BLVs.

European aspects of standard setting in occupational hygiene and medicine

Occupational standards concerning the allowable concentrations of chemical compounds in the ambient air of workplaces have been established in several countries at national levels. With the integration of the European Union, a need exists for establishing harmonized Occupational Exposure Limits. For analytical developments, it is apparent that methods for speciation or fractionation of carcinogenic metal compounds will be of increasing practical importance for standard setting. Criteria of applicability under field conditions, cost-effectiveness, and robustness are practical driving forces for new developments. When the European Union issued a list of 62 chemical substances with Occupational Exposure Limits in 2000, 25 substances received a 'skin' notation. The latter indicates that toxicologically significant amounts may be taken up via the skin. Similar notations exist on national levels. For such substances, monitoring concentrations in ambient air will not be sufficient; biological monitoring strategies will gain further importance in the medical surveillance of workers who are exposed to such compounds. Proceedings in establishing legal frameworks for a biological monitoring of chemical exposures within Europe are paralleled by scientific advances in this field. A new aspect is the possibility of a differential adduct monitoring, using blood proteins of different half-life or lifespan. This technique allows differentiation between long-term mean exposure to reactive chemicals and short-term episodes, for example, by accidental overexposure. For further analytical developments, the following issues have been addressed as being particularly important: New dose monitoring strategies, sensitive and reliable methods for detection of DNA adducts, cytogenetic parameters in biological monitoring, methods to monitor exposure to sensitizing chemicals, and parameters for individual susceptibilities to chemical toxicants.

Enhancing sense of recovery and self-reflectivity in people with schizophrenia : a pilot study of Metacognitive Narrative Psychotherapy

Objective This study investigated the effectiveness of an innovative, manualized psychotherapy aimed at enhancing recovery and self-experience in people with schizophrenia, Metacognitive Narrative Psychotherapy. Design Treatment effects were assessed using a mixed methodology. Data were quantitatively assessed using a single sample, pre- and post-therapy design and qualitatively assessed using a case-study methodology. Methods Eleven patients diagnosed with schizophrenia received Metacognitive Narrative Psychotherapy over the course of 11 to 26 months. Therapists were seven supervised postgraduate psychology students. On average patients attended 49 sessions over the course of therapy. Patients completed interview-based and self-report measures for general and treatment-specific outcomes at pre-, mid-, and post-treatment. Results Quantitative analyses showed that patients significantly improved on the general outcome of subjective recovery, as well as the treatment-specific outcome of self-reflectivity, with medium to large effect sizes. Case-study evidence also showed improvements for some patients in symptom severity, and narrative coherence and complexity. Conclusions These results are consistent with previous case-study evidence and suggest that this manualized version of Metacognitive Narrative Psychotherapy produces general and approach-specific improvements for people with schizophrenia. Replication is needed to ascertain its effectiveness with a larger sample size and within a controlled design.