Exposure And Risk Assessment Of Chemical Pollution Contemporary Methodology

The book contains the contributions at the NATO Study Institute on Exposure and Risk Assessment of Chemical Pollution – Contemporary Methodology, which took place in Sofia – Borovetz, Bulgaria, July 1–10, 2008. Rapid advances in mathematics, computer science and molecular biology and chemistry have lead to the development in of a new branch of toxicology called Computational Toxicology. This emerging field is addressing the estimation and prediction of exposure risk and effects of chemicals based on experimental data, measured concentration and biological mechanisms and computational models of biological systems. Mathematical models are also being used to predict the fate and transport of substances in the environment. Because this area is still in its infancy, there has been limited application from governmental agencies to regulating controllable processes, such as registration of new chemicals, determination of estimated exposure and risk based limits and maximum acceptable concentrations in different compartments of the environment – ambient air, waters, soil and food products. However, this is soon to change as the ability to collect, analyze and interpret the required information is becoming increasingly more efficient and cost effective. Full implementation of the new processes have to involve education on both part of the experimentalists who are generating the data and the models, and the risk assessors who will use them to better protect human health and the environment.

This book provides a concise, yet comprehensive overview of the many facets relating to human health risk assessments in relation to chemical exposure problems. It presents some very important tools and methodologies that can be used to address chemical exposure and public health risk management problems in a consistent, efficient, and cost-effective manner. On the whole, the book represents a collection and synthesis of the principal elements of the risk assessment process that may be used to more effectively address issues pertaining to human exposures to chemicals found in modern societies. This also includes an elaboration of pertinent risk assessment concepts and techniques/methodologies for performing human health risk assessments. Written for both the novice and the experienced, the subject matter of this book is an attempt at offering a simplified and systematic presentation of public health risk assessment methods and application tools – all these facilitated by a layout that will carefully navigate the user through the major processes involved. A number of illustrative example problems are interspersed throughout the book, in order to help present the book in an easy-to-follow, pragmatic manner.

In fact, with the control and containment of most infectious conditions and diseases of the past millennium having been achieved in most developed countries, and with the resultant increase in life expectancies, much more attention seems to have shifted to degenerative health problems. Many of the degenerative health conditions have been linked to thousands of chemicals regularly encountered in human living and occupational/work environments. It is important, therefore, that human health risk assessments are undertaken on a consistent basis - in order to determine the potential impacts of the target chemicals on public health.

The Council of the North Atlantic Treaty Organization (NATO) established the "Committee on the Challenges of Modern Society" (CCMS) in 1969. The CCMS was charged with developing meaningful environmental and social programmes for solving existing problems and developing long-range goals for environmental protection. In 1983, at the Fall Plenary of the CCMS, the Norwegian delegate Dr. H.C. Christensen, proposed a Pilot Study on "Risk Management of Chemicals in the Environment". A draft proposal, written by Dr. Kari Kveseth of the Center for Industrial Research in Oslo, was presented. Dr. Christensen also informed the participants at the meeting that Norway was willing to act as the Pilot Country. The project was initially planned for 3 years, but it was later extended through 1987. The inaugural meeting was held in Oslo in April 1984 with participants from Denmark, Greece, France and Italy, in addition to representatives from several Norwegian institutions. The attendees concluded that a Pilot Study, as delineated in the draft proposal, would be useful, and it was decided to work out a detailed project plan based on the proposal.

Over the last decade, several large-scale United States and international programs have been initiated to incorporate advances in molecular and cellular biology, -omics technologies, analytical methods, bioinformatics, and computational tools and methods into the field of toxicology. Similar efforts are being pursued in the field of exposure science with the goals of obtaining more accurate and complete exposure data on individuals and populations for thousands of chemicals over the lifespan; predicting exposures from use data and chemical-property information; and translating exposures between test systems and humans. Using 21st Century Science to Improve Risk-Related Evaluations makes recommendations for integrating new scientific approaches into risk-based evaluations. This study considers the scientific advances that have occurred following the publication of the NRC reports Toxicity Testing in the 21st Century: A Vision and a Strategy and Exposure Science in the 21st Century: A Vision and a Strategy. Given the various ongoing lines of investigation and new data streams that have emerged, this publication proposes how best to integrate and use the emerging results in evaluating chemical risk. Using 21st Century Science to Improve Risk-Related Evaluations considers whether a new paradigm is needed for data validation, how to integrate the divergent data streams, how uncertainty might need to be characterized, and how best to communicate the new approaches so that they are understandable to various stakeholders.

Traditionally, industrial hygienists and environmental engineers have been responsible for conducting chemical exposure assessments, however, this task is now becoming a team effort taken on by scientists, businessmen, and policymakers. Assessment of Chemical Exposures: Calculation Methods for Environmental Professionals addresses the expanding scope of exposure assessments in both the workplace and environment. It discusses the basics of gathering data and assessing exposure, including how to estimate exposure to chemicals using fundamental chemical engineering concepts. The book opens with a brief discussion on the history of exposure assessments and provides terms and nomenclature needed for communications between various disciplines involved in exposure assessments. The potential impact of chemical exposures on humans, the environment, and communities is discussed in detail The book also addresses modeling source generation, pathway transport, and receptor impact. With the clear explanations presented in this text, even a novice will be able to practice the art of exposure assessment.

This volume examines every potential means of exposure to water contaminants, provides in-depth discussions on toxicology, and explains up-to-date techniques for evaluating human health risk. It develops a methodology for assessing the cumulative absorbed dose of contaminants through all routes of exposure, including ingestion, inhalation and dermal. Federal and state efforts to monitor and treat water are examined.

Assessment of human exposure to chemicals is a critical input to risk assessment and ultimately to decisions about control of chemicals. This two-part publication aims to improve the quality of information available to decision-makers and its communication. Part one sets out ten principles for characterizing and communicating uncertainty in exposure assessment. A tiered approach to the evaluation of uncertainties using both qualitative (simple) and quantitative (more complex) methods is described. Different sources of uncertainty are identified and guidance is provided on selecting the appropriate approach to uncertainty analysis as dictated by the objectives of the assessment and information needs of decision-makers and stakeholders. Part two addresses the quality of data used in exposure assessment and sets out four basic hallmarks of data quality - appropriateness accuracy integrity and transparency. These hallmarks provides a common vocabulary and set of qualitative criteria for use in the design evaluation and use of exposure assessments to support decisions. This publication is intended exposure assessors risk assessors and decision-makers.