Risk-based waste classification in California / Committee on Risk-Based Criteria for Non-RCRA Hazardous Waste, Board on Environmental Studies and Toxicology, Commission on Life Sciences, National Research Council.

Format:

Book

Contributor:

National Research Council (U.S.). Committee on Risk-Based Criteria for Non-RCRA Hazardous Waste.

Series:

Compass series (Washington, D.C.)

Compass series

Language:

English

Subjects (All):

Hazardous wastes--California.

Hazardous wastes.

Risk assessment--California.

Risk assessment.

Physical Description:

1 online resource (235 p.)

Edition:

1st ed.

Place of Publication:

Washington, D.C. : National Academy Press, 1999.

Language Note:

English

Summary:

The Department of Toxic Substances Control (DTSC) of the State of California Environmental Protection Agency is in the process of complying with the Regulatory Structure Update. The Regulatory Structure Update is a comprehensive review and refocusing of California's system for identifying and regulating management of hazardous wastes. As part of this effort, the DTSC proposes to change its current waste classification system that categorizes wastes as hazardous or nonhazardous based on their toxicity. Under the proposed system there would be two risk-based thresholds rather than the single toxicity threshold currently used to distinguish between the wastes. Wastes that contain specific chemicals at concentrations that exceed the upper threshold will be designated as hazardous; those below the lower threshold will be nonhazardous; and those with chemical concentrations between the two thresholds will be "special" wastes and subject to variances for management and disposal. The proposed DTSC system combines toxicity information with short or long-term exposure information to determine the risks associated with the chemicals. Under section 57004 of the California Health and Safety Code, the scientific basis of the proposed waste classification system is subject to external scientific peer review by the National Academy of Sciences, the University of California, or other similar institution of higher learning or group of scientists. This report addresses that regulatory requirement.

Contents:

Risk-Based Waste Classification in California

Copyright

OTHER REPORTS OF THE BOARD ON ENVIRONMENTAL STUDIES AND TOXICOLOGY

Preface

Contents

Abbreviations

Risk-Based Waste Classification In California

Executive Summary

THE COMMITTEE'S TASK

WHAT IS BEING REVIEWED?

DTSC'S CURRENT CLASSIFICATION SYSTEM

DTSC'S PROPOSED CLASSIFICATION SYSTEM

THE NRC COMMITTEE'S FINDINGS AND RECOMMENDATIONS

Risk-Based Waste Classification

Exposure Pathway Integration

Protection Goals and Exposure Scenarios

Model Components and Parameters

Model Performance

Analytical Issues

Risk for Entire Waste

Chronic Toxicity Data and Irritation Testing

Transparency of the Proposed Approach

Flexibility Goals

CONCLUSIONS

1 Introduction

THE COMMITTEE'S TASK AND APPROACH

REPORT ORGANIZATION

OVERVIEW OF CALIFORNIA'S APPROACH TO CLASSIFYING HAZARDOUS WASTE

Statutory Framework

Current Waste-Classification System

Need for Change in Waste-Classification System

Proposed Waste-Classification System

Toxicity Criteria

Total Threshold Limit Concentrations

Soluble or Extractable Regulatory Thresholds

Other Toxicity Criteria

Exposure Models

CalTOX Model

Preliminary Endangerment Assessment Model

Lead Risk-Assessment Spreadsheet Model

Potential Regulatory Impacts

2 DTSC's Proposed Overall Approach

STATEMENT OF GOALS

MULTIMEDIA AND MULTIPATHWAY RISK ASSESSMENT

REALISTIC EXPOSURE SCENARIOS

VALID SCIENCE

TRANSPARENCY

FLEXIBILITY

IMPLEMENTATION PRACTICALITY AND EVALUATION

3 Scenario Selection and Modeling

EXPOSURE SCENARIOS: PURPOSE

MODELING: PURPOSE

SUMMARY OF DTSC EXPOSURE SCENARIOS

Adjacent Resident Scenario

Waste Worker Scenario

Land Conversion Scenario

Ecological Effects Scenario

MODELING USED IN THE SCENARIOS.

ANALYSIS OF SCENARIOS AND MODELING

Scenarios: Connection to Policy

Scenarios: Completeness and Coverage

Scenarios: Physical Processes and Models

Mathematical Models and Their Implementation

Scenarios and Models: Parameter Values

Models: Variability and Uncertainty

Models: Sensitivity Analyses

Models: Validation and Quality Control

ECOLOGICAL SCENARIO

4 Issues of Model Application

MODEL PARAMETERS

Parameter Selection for Scenarios

Food Intake

Fruits and Vegetables

Grains

Meat, Dairy, and Eggs

Fish

PARAMETER SELECTION WITHIN SPECIFIC MODELS

Calculations for Lower SERTs

Calculations for Upper SERTs

Preliminary Endangerment Assessment

Risk and Hazard Spreadsheets

Exposure Pathway Factor for Inhalation

Dust

Quantitation of Intake for Workers

Concentration limit in Waste

Monte Carlo Analysis

LeadSpread

CalTOX

Dust-Deposition Velocity

Organic Carbon Content of Residential Soil

Molecular Weight

Chemical Properties

ANALYTICAL METHODS

TOXICITY TESTS

Tests Related to Human Health

Tests Related to Ecology

5 Meeting Program Goals

RSU GUIDING PRINCIPLES

Protect Public Health and Environment

Regulatory Flexibility and Simplicity

DTSC PROGRAM GOALS

Considering Exposure in Classification of Waste

Incorporating New Toxicological or Technical Data

Developing a Mechanism for Regulating Chemicals Other Than the 36 SERT and 38 TTLC Chemicals

OTHER CONSIDERATIONS FOR DTSC'S APPROACH

PROGRAM EVALUATION

References

Appendix A Biographical Information on the Committee on Risk-Based Criteria for Non-RCRA Hazardous Waste

Appendix B DTSC Issues

Appendix C List of Public Access Materials Received by the NRC Committee on Risk-Based Criteria for Non-RCRA Hazardous Waste.

Appendix D California Environmental Protection Agency Department of Toxic Substances Control (DTSC)

1. OVERVIEW

Total Threshold Limit Concentrations (TTLCs)

Human Health Risk Assessment Scenarios and Models

Upper TTLCs

Exit-level TTLCs

Soluble or Extractable Regulatory Thresholds (SERTs)

2. ISSUES

TTLC issues

Model Selection

Scenario Selection

SERT issues

Acute Toxicity Issues

DESCRIPTION OF ISSUES

The Waste Classification Review

The Existing California System

RECOMMENDATION

CIRCUMSTANCES NECESSITATING A DECISION

EXISTING STATUTES OR REGULATIONS RELATED TO THE ISSUE

Objectives to be Achieved Through Decision

Alternatives Available and Recommended Alternative

A. Subsection 66261.24(a)(2)(A&amp

B)

Recommended Alternative: Alternative 3

B. Subsection 66261.24(a)(2)(A&amp

C. Subsection 66261.24 (a)(3)

D. Subsection 66261.24 (a)(4)

E. Subsection 66261.24 (a)(5)

F. Subsection 66261.24 (a)(6)

Recommended Alternative: Alternative 4

G. Subsection 66261.24 (a)(7)

H. Subsection 66261.24 (a)(8)

Recommended Alternative: Alternative 2

Implementation of the Recommended Alternatives

A. Modifications to Section 66261.24(a)(2): SERTs

B. Modifications to Section 66261.24(a)(2): TTLCs

Regulation of Wastes Containing Elemental Metals

C. Modifications to Section 66261.24(a)(3): Acute Oral LD50

D. Modifications to Section 66261.24(a)(4): Acute Dermal LD50

E. Modifications to Section 66261.24(a)(5): Acute Inhalation LC50

F. Modifications to Section 66261.24(a)(6): Aquatic Toxicity.

G. Modifications to Section 66261.24(a)(7): Listed Carcinogens

H. Modifications to Section 66261.24(a)(8): New Threats

I. Classification of wastes under the proposed regulatory structure

Reclassifications and Variances

Appendix 1: Regulated chemicals

Organic Chemicals

Inorganic Chemicals

Appendix 2: Derivation of proposed SERTs

Lower (exit-level) SERTs

Upper SERTs

Solubility, STLCs, and TTLCs

Appendix 3: TTLCs

Introduction

What is the purpose of this appendix?

What is the relationship between ground water and TTLCs?

Why are TTLCs developed for individual chemicals instead of waste streams?

Why were these 38 chemicals selected?

What is the purpose of two tiers of TTLCs?

How are the upper and lower (exit-level) TTLCs selected?

First Stage: Computation of Risk-Based TTLCs

How is quantitative risk assessment used to assess effects on human health and the environment?

What is multimedia exposure assessment?

Mathematical Models and Regulatory Decisions

How is uncertainty treated in developing TTLCs?

Description of the Exposure Scenarios

Disposal Practices

Potentially Exposed Populations

Exposure Scenarios

Models used for determining risk-based criteria for the scenarios

What is CalTOX and why was it chosen?

What modifications have been made to CalTOX and why?

What is the Lead spreadsheet model and why was it chosen?

What modifications have been made to the Lead spreadsheet model and why?

What is the Preliminary Endangerment Assessment model and why was it chosen?

What modifications have been made to the PEA and why?

How were effects on non-human species evaluated?

Second Stage: Detection Limits and Ambient Concentrations

Estimated Quantification Limits

Comparison with Background Concentrations

References.

Appendix 4. Acute Toxicity Thresholds

Oral LD50

Dermal LD50

Inhalation LC50

Aquatic Toxicity.

Notes:

Bibliographic Level Mode of Issuance: Monograph

Includes bibliographical references.

ISBN:

9786610185900

9780309184038

0309184037

9781280185908

1280185902

9780309539111

0309539110

9780585085784

0585085781

OCLC:

43475749