Environmental Risk Assessment

Ted Simon, DABT earned advanced degrees in biology, including a Ph.D from Georgia State University, Atlanta, USA. After college, he held post-doctoral and teaching positions before serving as senior toxicologist in the Waste Management Division at the Environmental Protection Agency (EPA), Region 4, Atlanta, Georgia, USA. His critically successful novel, A Lost Gun, was published under the nom de plume Wix Simon. He is currently working on another crime novel featuring an environmental poisoning situation inspired by his twelve years at the EPA. He also provides toxicology consulting and scientific support as principal/owner of Ted Simon LLC, Winston, Georgia, USA.

Introduction
Risk Assessment Paradigm from the 1983 Redbook-"Risk Assessment in the Federal Government: Managing the Process"


Risk Assessment Guidance for Superfund (RAGS) Part A 1989


The Interface of Risk Assessment and Risk Management


History of Risk Assessment in the US from 1990 to 2010


Risk Communication and Stakeholder Participation


Risk Assessment Policy and the Role of Science





How Risk is Perceived and Expressed


Actuarial Risk


Predicted Risk


Perceived Risk


Risk Estimates for Regulation


Uncertainty in Risk Estimates


Uncertainty in Risk Management and the Precautionary Principle





Human Health Exposure Assessment


What are Receptors?


How are Receptors Exposed to Environmental Stressors?


Human Exposure Assessment


Assessing Exposure Factors and Data


Issues to Be Considered When Performing an Exposure Assessment


The Concentration Term


Fate and Transport Models


Accounting For Uncertainty In Exposure Factors





Toxicity Assessment for Human Health Risk Assessment


Mode of Action and General Aspects of Toxicity


Homeostasis and Thresholds


Historical Perspective on Toxicity Testing


Timescale and Nature of Adverse Effects


Dose-Response Assessment


Low Dose Extrapolation-Two Types of Toxicity Factors


Computational Methods in Toxicity Assessment


Mixtures


Accounting For Uncertainty in Toxicity Factors


Toxicity Factors for Regulation





Risk Characterization


Hazard Quotient for Threshold Effects


Risk Estimation for Non-Threshold Effects


Cumulative and Aggregate Risk


The Possibility of Compounding Conservatism in Both Exposure and Toxicity


The Precautionary Principle


Utility of Risk Characterization for Decision Making





Ecological Risk Assessment


Statutory Aspects of ERA at EPA and the Role of Natural Resource Trustees


ERA Under REACH


Ecological Risk Assessment as Practiced By EPA


Methodology for ERA under REACH


Science Policy of ERA





The Future of Risk Assessment


In Vitro Testing and ‘Omics-Toxicity Testing in the 21st Century


Science and Decisions: Advancing Risk Assessment


Recommendations for Improving IRIS in the 2011 NAS Review of the Formaldehyde Risk Assessment


Possible Future Scenarios for Risk Assessment: Scientific, Social and Political Factors in Societal Decision Making





Appendix A: Useful Methods and Algorithms for Probabilistic Risk Assessment (PRA)