Hazardous Waste Risk Assessment

Kofi Asante-Duah

• Publisher: CRC Press
• Year: 2021
• Print ISBN:
  9780367449971
• eBook ISBN:
  9781000157826
• Topic: Medicine
• Subtopic: Medical Theory, Practice & Reference

Hazardous Waste Risk Assessment provides a concise yet comprehensive examination of concepts and techniques in risk assessment that can be applied to hazardous waste problems. The book emphasizes the use of health risk assessment to support management decisions on hazardous waste disposal and site remediation programs. Methods discussed include those for developing strategies for health and environmental assessment and site restoration tasks, evaluating corrective action programs, determining the effects of risk assessment results on risk management decisions in hazardous waste programs and general risk management and prevention programs, and performing safety evaluations of hazardous waste facilities. Step-by-step numerical case evaluations are used to help present the book in an easy-to-follow, realistic manner. Features

CHAPTER 1

Introduction

Waste production is an inevitable characteristic of an industrial society. The effective management of hazardous wastes, and the associated treatment, storage, and disposal facilities (TSDFs), is of major concern not only to the industry producing such material, but also to governments and individual citizens alike due to the nature and potential impact of such wastes on the environment and public health. In particular, hazardous waste management is of great concern in view of the uncertainties and risks associated with waste disposal activities. Apart from its immediate and direct health and environmental hazards, hazardous waste disposal could lead to the long-term contamination of the ambient air, soils, surface and ground waters, and the food chain if disposal facilities are not properly designed and maintained or if remedial actions are not taken in an effective manner. In fact, this is in a way summarized by Clapham’s (Bhatt et al., 1986) view of hazardous waste management facilities as the kidneys of industrial societies. A responsible system for dealing with hazardous wastes is therefore essential to sustain the modern way of life, inasmuch as a well-functioning kidney is necessary to rid the human body of certain toxins.

Hazardous waste sites and facilities, in particular, and potentially contaminated sites, in general, may pose significant risks to the public because of the potential health and environmental effects and to the potentially responsible parties (PRPs) because of the potential financial liabilities resulting from their effects. The effective management of such sites and facilities has therefore become an important environmental priority and will be a growing social challenge for years to come. However, it has also become evident that the proper management of hazardous wastes poses great challenges. Risk assessment, which encompasses varying degrees and types of qualitative and quantitative analyses, is one of the fastest evolving tools for developing appropriate management strategies relating to hazardous waste management decisions. The U.S. Environmental Protection Agency (EPA) recognizes the use of risk assessment to facilitate decisions on whether or not remedial actions are needed to abate site-related risks, and also in the enforcement of regulatory standards. Risk assessment techniques have been used in various regulatory programs employed by federal, state, and local agencies. For instance, both the feasibility study process under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA, or “Superfund”) and alternate concentration limit (ACL) demonstrations under the Resource Conservation and Recovery Act of 1976 (RCRA) involve the use of risk assessment to establish cleanup standards for contaminated sites.

The primary application of quantitative risk assessment in the U.S. EPA Superfund program is to evaluate the potential risk posed at each National Priorities List (NPL) facility, so that the appropriate remedial alternative can be identified (Paustenbach, 1988); NPL is the list of uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial actions under Superfund. The U.S. EPA uses a risk-based evaluation method, the Hazard Ranking System (HRS), to identify uncontrolled and abandoned hazardous waste sites falling under Superfund programs. The HRS allows the selection or rejection of a site for placement on the U.S. EPA NPL; it is used for prioritizing sites so that those posing the greatest risks receive quicker response. Another application of risk assessment is in the selection of appropriate sites for hazardous waste facilities; sites are ranked for their appropriateness for stipulated purpose(s) according to the levels of risk that each potentially poses under different scenarios. Furthermore, ACLs (which can be considered as surrogate values for the maximum allowable health and environmental exposure levels) can be established when hazardous constituents are identified in groundwater at RCRA facilities, by applying risk assessment procedures in the analytical processes involved. In fact, nearly every process for developing cleanup criteria incorporates some concept that can be classified as a risk assessment. Thus, all decisions on setting cleanup standards for potentially contaminated sites include, implicitly or explicitly, some aspect of risk assessment. In all situations, to ensure public safety, contaminant migration beyond a compliance boundary into the public exposure domain must be below some stipulated health-based standard, or a maximum exposure level (MEL). Indeed, to ensure public health and environmental sustainability, decisions relating to hazardous waste management should be based on a systematic and scientifically valid process, such as is offered by risk assessment.

1.1 THE NATURE OF HAZARDOUS WASTES

Broadly speaking, a hazardous material is one which is capable of producing adverse effects and/or reactions in potential biological receptors; toxic concentrations of substances generally present unreasonable risk of harm to human health and/or the environment. Such substances need to be regulated. Specifically, hazardous waste is that by-product which has the potential of causing detrimental effects on human health and/or the environment if not managed efficiently. Such wastes may belong to one or more of several categories, including

• Toxic organic or inorganic chemicals

• Bioaccumulative materials

• Nondegradable and persistent chemicals

• Radioactive substances

Hazardous waste disposal practices may result in the release of chemicals into air (via volatilization and fugitive dust emissions), surface water (from surface runoff or overland flow and groundwater seepage), groundwater (through leaching/infiltration), soils (due to erosion, including fugitive dust generation/deposition, and tracking), sediments (from surface runoff/overland flow, seepage, and leaching), and biota (due to biological uptake and bioaccumulation). For instance, typical chemicals finding their way into drinking water aquifers have been reported elsewhere to include aliphatic hydrocarbons (e.g., chloroform, vinyl chloride); aromatic hydrocarbons (e.g., benzene, toluene, xylene, DDT, benzo[a]pyrene [BaP] from coal tar); chlorinated solvents; pesticides; polychlorinated biphenyls (PCBs); trace metals and other inorganic compounds (e.g., arsenic, cadmium, chromium, cyanide, lead, mercury); and other organic compounds (e.g., acetone, methyl ethyl ketone). These and several other chemicals may be present in the environment, and can lead to several detrimental effects.

The identification of potentially hazardous waste streams is important in the investigation of potential risks that such wastes may present. The wastes generally originate from any of a number of industries (Table 1.1). These industries generate several waste types such as organic waste sludges and still bottoms (containing chlorinated solvents, metals, oil, etc.); oil and grease (with PCBs, polyaromatic hydrocarbons [PAHs], metals, etc.); heavy metal solutions (of arsenic, cadmium, chromium, lead, mercury, etc.); PCB wastes; pesticide and herbicide wastes; anion complexes (with cadmium, copper, nickel, zinc, etc.); paint and organic residuals; and several miscellaneous chemicals and products. There is always some risk of chemicals from these waste streams escaping into the environment during treatment storage, or final disposal.

Table 1.1 Typical Industries Generating Potentially Hazardous Wastes

Aerospace

Automobile

Batteries (storage and primary)

Beverages

Computer manufacture

Electronic components manufacturing

Electroplating and metal finishing

Explosives

Food processing and dairy products

Ink formulation

Inorganic chemicals

Inorganic pigments

Iron and steel

Leather tanning and finishing

Metal smelting and refining

Organic chemicals

Paints and coatings

Perfumes and cosmetics

Pesticides and herbicides

Petroleum refining

Pharmaceuticals

Photographic equipment and supplies

Printing

Pulp and paper mills

Rubber products, plastic materials, and synthetics

Ship building

Soap and detergent manufacturing

Textile mills

Wood preservation and processing

1.2 WASTE CLASSIFICATION SYSTEMS

In order to develop effective pollution control strategies, wastes must be appropriately categorized. A typical categorization will comprise putting the wastes into high-, intermediate-, and low-risk classes (Figure 1.1). The high-risk wastes will be those of priority concern, known to contain significant concentrations of constituents that are highly toxic, mobile, persistent, and/or bioaccumulative. Examples of this type of waste are chlorinated solvent wastes from metal degreasing (due to their toxicity, mobility, and to some extent, persistence in the environment, etc.); cyanide wastes (due to their high toxicity, etc.); dioxin-based wastes (due to potential high toxicity and carcinogenicity effects, etc.); PCB wastes (due to persistence and bioaccumulative properties, etc.). Intermediate...

Table of contents

• Cover
• Title Page
• Copyright Page
• Dedication
• Preface
• Acknowledgments
• Contents
• Chapter 1 Introduction
• Chapter 2 Fundamentals of Hazard, Exposure, and Risk Assessment
• Chapter 3 Concepts in Risk Assessment
• Chapter 4 The Risk Assessment Process
• Chapter 5 Risk Assessment Techniques and Methods of Approach
• Chapter 6 Hazardous Waste Management Decisions from Risk Assessment
• Chapter 7 Selected Case Studies and Applications
• Chapter 8 Epilogue
• Additional Bibliography
• Appendix A Abbreviations, Acronyms, and Glossary of Terms and Definitions
• Appendix B Relevant Equations Commonly Utilized in Human Health Risk Assessments
• Appendix C Carcinogen Classification and Identification Systems
• Appendix D Selected Databases and Information Library With Important Risk Information Used in Risk Assessment
• Appendix E Selected Units and Measures
• Index