New Directions in Health Risk Assessment: A REACH for the Future?
Health risk assessments have been used to support many decisions in the US to reduce risks from pollutant exposures. These decisions have been highly successful in protecting public health despite uncertainty due to gaps in knowledge and methodological limitations. In recent years, the production of Integrated Science Assessments (ISA) of the criteria air pollutants (formerly, Air Quality Criteria Documents) has accelerated due to court-ordered mandates and successful efforts at streamlining. ISA documents emphasize interpretation of epidemiology, clinical, and human exposure data that are available for these few pollutants, with animal toxicology data typically playing a supportive role. In addition, the number of Integrated Risk Information System (IRIS) assessments for air toxics and other pollutants in development has increased in recent years. IRIS assessments typically rely on data extrapolated from animal toxicology studies to estimate risks in humans. Debates over the interpretation of science and procedural requirements have intensified and, as a result, IRIS assessment completions have slowed. In Europe, a new regulation, the Registration, Evaluation, Authorisation and Restriction of Chemical Substances (REACH) framework, presents a paradigm shift for risk assessment and risk management and is accompanied by requirements that substantial new information, largely from animal toxicology or computational toxicology studies, be produced by industry to support chemical exposure evaluations. With substantial new data on the horizon from REACH and with rapid advances in computational toxicology it is easy to envision a rapidly changing landscape for health risk assessment, especially for air toxics,toxic waste and water pollutants. The REACH regulation and advances in computational toxicology provide an impetus for the US to plan, evaluate and implement new approaches for scientific assessments. By extension, these developments need to be linked to existing and new policy directions.