Assessment Of Chemical Exposures

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.

People are exposed to a variety of chemicals throughout their daily lives. To protect public health, regulators use risk assessments to examine the effects of chemical exposures. This book provides guidance for assessing the risk of phthalates, chemicals found in many consumer products that have been shown to affect the development of the male reproductive system of laboratory animals. Because people are exposed to multiple phthalates and other chemicals that affect male reproductive development, a cumulative risk assessment should be conducted that evaluates the combined effects of exposure to all these chemicals. The book suggests an approach for cumulative risk assessment that can serve as a model for evaluating the health risks of other types of chemicals.

Introduction to Chemical Exposure and Risk Assessment focuses on the principles involved in assessing the risks from chemical exposure. These principles include the perception of risk, an understanding of how numbers are handled, and how chemicals affect health. The book briefly describes the major sinks, such as water and air, where chemicals are introduced. This is followed by a discussion on how concentrations are estimated and risk assessments are made. A discussion of risk benefit analysis and a presentation of several case studies using the principles for assessing risks are also included.

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.

Historically, regulations governing chemical use have often focused on widely used chemicals and acute human health effects of exposure to them, as well as their potential to cause cancer and other adverse health effects. As scientific knowledge has expanded there has been an increased awareness of the mechanisms through which chemicals may exert harmful effects on human health, as well as their effects on other species and ecosystems. Identification of high-priority chemicals and other chemicals of concern has prompted a growing number of state and local governments, as well as major companies, to take steps beyond existing hazardous chemical federal legislation. Interest in approaches and policies that ensure that any new substances substituted for chemicals of concern are assessed as carefully and thoroughly as possible has also burgeoned. The overarching goal of these approaches is to avoid regrettable substitutions, which occur when a toxic chemical is replaced by another chemical that later proved unsuitable because of persistence, bioaccumulation, toxicity, or other concerns. Chemical alternative assessments are tools designed to facilitate consideration of these factors to assist stakeholders in identifying chemicals that may have the greatest likelihood of harm to human and ecological health, and to provide guidance on how the industry may develop and adopt safer alternatives. A Framework to Guide Selection of Chemical Alternatives develops and demonstrates a decision framework for evaluating potentially safer substitute chemicals as primarily determined by human health and ecological risks. This new framework is informed by previous efforts by regulatory agencies, academic institutions, and others to develop alternative assessment frameworks that could be operationalized. In addition to hazard assessments, the framework incorporates steps for life-cycle thinking - which considers possible impacts of a chemical at all stages including production, use, and disposal - as well as steps for performance and economic assessments. The report also highlights how modern information sources such as computational modeling can supplement traditional toxicology data in the assessment process. This new framework allows the evaluation of the full range of benefits and shortcomings of substitutes, and examination of tradeoffs between these risks and factors such as product functionality, product efficacy, process safety, and resource use. Through case studies, this report demonstrates how different users in contrasting decision contexts with diverse priorities can apply the framework. This report will be an essential resource to the chemical industry, environmentalists, ecologists, and state and local governments.

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.

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.