United States Office of Water EPA 822-P-16-002 Environmental Mail Code 4304T December 2016 Protection Agency Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin Draft Human Health Recreational Ambient Water Quality Criteria or Swimming Advisories for Microcystins and Cylindrospermopsin Draft Prepared by: U.S. Environmental Protection Agency Office of Water (4304T) Health and Ecological Criteria Division Washington, DC EPA Document Number: 822-P-16-002 Date: December 2016 NOTICES This information is distributed solely for the purpose of obtaining scientific views on the content of this document. It does not represent and should not be construed to represent any final agency determination or policy. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. Human Health Recreational Ambient Water Quality Criteria or ii Swimming Advisories for Microcystins and Cylindrospermopsin – Draft FOREWORD Section 304(a) of the Clean Water Act requires the Administrator of the Environmental Protection Agency to publish water quality criteria that accurately reflect the latest scientific knowledge on the kind and extent of all identifiable effects on health and welfare that might be expected from the presence of pollutants in any body of water, including ground water. U.S. Environmental Protection Agency (EPA) is publishing these recommended values under Clean Water Act (CWA) 304(a) for states to consider as the basis for swimming advisories for notification purposes in recreational waters to protect the public. Alternatively, states may consider using these same values when adopting new or revised water quality standards (WQS). If adopted as WQS and approved by EPA under CWA 303(c), the WQS could be used for all CWA purposes. States may also wish to consider using these values as both swimming advisory values and WQS. EPA envisions that if states decide to use the values as swimming advisory values they might do so in a manner similar to their current recreational water advisory programs. This draft document has undergone an EPA intra-agency peer review process. Final review by the Health and Ecological Criteria Division, Office of Science and Technology, Office of Water, U.S. Environmental Protection Agency has been completed and the document is approved for publication. These values were derived using the existing peer-reviewed and published science on the adverse human health effects of these toxins, established criteria methodologies, and recreation-specific exposure parameters from EPA's Exposure Factors Handbook. The term “water quality criteria” is used in two sections of the CWA§304(a)(1) and §303(c)(2). The term has a different program impact in each section. In section 304, the term represents a non-regulatory, scientific assessment of effects on human health or aquatic life. The criteria recommendations presented in this document are such a scientific assessment. If water quality criteria associated with specific designated uses are adopted by a state or authorized tribe as water quality standards under section 303, and approved by EPA, they become applicable Clean Water Act water quality standards in ambient waters within that state or tribe. Water quality criteria adopted in state or tribal water quality standards could have the same numerical values as criteria developed under section 304. Alternatively, states and authorized tribes may derive numeric criteria based on other scientifically defensible methods but the criteria must be protective of designated uses. It is not until their adoption as part of state or tribal water quality standards, and subsequent approval by EPA, that criteria become Clean Water Act applicable water quality standards. Guidelines to assist in modifying the criteria recommendations presented in this document are contained in the Water Quality Standards Handbook (U.S. EPA 2012b). This handbook and additional guidance on the development of WQS and other water-related programs of this agency have been developed by EPA which along with additional guidance on the development of water quality standards and other water-related programs of this Agency have been developed by the Office of Water. This document provides recommendations only. It does not establish or affect legal rights or obligations. It does not establish a binding norm and cannot be finally determinative of the issues addressed. Agency decisions in any particular situation will be made by applying the Clean Water Act and EPA regulations on the basis of specific facts presented and scientific information then available. Human Health Recreational Ambient Water Quality Criteria or iii Swimming Advisories for Microcystins and Cylindrospermopsin – Draft /signed/ Elizabeth Southerland Director Office of Science and Technology Human Health Recreational Ambient Water Quality Criteria or iv Swimming Advisories for Microcystins and Cylindrospermopsin – Draft ACKNOWLEDGMENTS The development of this document was made possible through an effort led by John Ravenscroft, EPA Project Manager, Health and Ecological Criteria Division, Office of Science and Technology, Office of Water. Additionally, the following Office of Science and Technology staff provided valuable contributions to the development and review of this document: Tracy Bone, Dr. Lesley D’Anglada, Ashley Harper, Ana-Maria Murphy-Teixidor, and Lars Wilcut, and Oakridge Institute for Science and Education (ORISE) fellow Meghann Niesen. EPA gratefully acknowledges the valuable contributions of EPA Internal Technical Reviewers who reviewed this document. This recreational Ambient Water Quality Criteria (AWQC) was provided for review and comment from a formal internal agency review by staff in the following U.S. EPA Program and Regional Offices: U.S. EPA Office of Children’s Health Protection: Suril Mehta U.S. EPA Office of General Counsel: David Berol, Lee Schroer U.S. EPA Office of Policy: Sharon Cooperstein U.S. EPA Office of Research and Development: Neil Chernoff, Paula Estornell (on detail), Elizabeth Hilborn, Christopher Impellitteri, Nicole Shao U.S. EPA Office of Water Office of Ground Water and Drinking Water: Hannah Holsinger, Mike Muse Office of Science and Technology: Tracy Bone Office of Wastewater Management: David Hair, Virginia Kibler Office of Wetlands, Oceans, and Watersheds: Rosaura Conde, Katharine Dowell U.S. EPA Regional Offices Region 1: Toby Stover Region 4: Joel Hansel Region 5: Meghan Hemkin Region 7: Amy Shields Region 8: Alfred Basile, Tina Laidlaw Technical support was provided by ICF and its subcontractor Bigelow Laboratory for Ocean Sciences. Human Health Recreational Ambient Water Quality Criteria or v Swimming Advisories for Microcystins and Cylindrospermopsin – Draft TABLE OF CONTENTS NOTICES ........................................................................................................................................ ii FOREWORD ................................................................................................................................. iii ACKNOWLEDGMENTS .............................................................................................................. v TABLE OF CONTENTS ............................................................................................................... vi LIST OF FIGURES ..................................................................................................................... viii LIST OF TABLES ......................................................................................................................... ix ACRONYMS AND ABBREVIATIONS ...................................................................................... xi 1.0 EXECUTIVE SUMMARY ..................................................................................................... 1 2.0 INTRODUCTION AND BACKGROUND ............................................................................ 3 2.1 Clean Water Act ................................................................................................................... 6 2.2 International and State Guidelines ....................................................................................... 7 3.0 NATURE OF THE STRESSORS ......................................................................................... 15 3.1 Cyanobacteria and Cyanobacterial Blooms ....................................................................... 15 3.2 Cyanotoxins ........................................................................................................................ 21 3.2.1 Chemical and Physical Properties ............................................................................... 21 3.2.2 Sources and Occurrence .............................................................................................. 24 3.2.3 Environmental Fate ..................................................................................................... 30 3.2.4 Toxicokinetics ............................................................................................................. 33 4.0 PROBLEM FORMULATION .............................................................................................. 34 4.1 Conceptual Model .............................................................................................................. 34 4.2 Analysis Plan .....................................................................................................................