Drinking Water Contaminants of Emerging Concern Program
Total Page：16
File Type：pdf, Size：1020Kb
Final Draft Drinking Water Contaminants of Emerging Concern Program Special Project: Evaluating, Testing, and Reporting of Alternative Risk Assessment Methods Selection, Evaluation and Recommendations of Viable Alternative Risk Assessment Methods for the Development of Drinking Water Guidance Values Prepared for: Minnesota Department of Health Contaminants of Emerging Concern (CEC) Program Environmental Health Division 625 N. Robert Street St. Paul, MN 55164 Prepared by: Jeff Stevens, PhD J.B. Stevens & Associates 8477 Rice Lake Road Maple Grove, MN 55369 Submitted: July 25, 2012 [Note: MDH staff have made limited revisions to this report for the sake of clarity, correction, or formatting. This report does not represent official agency policy but may be used to inform future work.] ABBREVIATIONS AND ACRONYMS ADI Acceptable Daily Intake ALAP As Low As Practical ALARA As Low As Reasonably Achievable B(a)P Benzo(a)pyrene CalEPA California Environmental Protection Agency CEC Contaminants of Emerging Concern CPSC Consumer Product Safety Commission DNA Deoxyribonucleic acid DOE US Department of Energy EF Extrapolation Factor EU European Union FAO Food and Agriculture Organization of the United Nations FDA US Food and Drug Administration HBV Health Based Value HGPRT Hypoxanthine-guanine phosphoribosyl transferase HPV High Production Volume HRL Health Risk Limit HSDB Hazardous Substance Data Bank ICRP International Commission on Radiological Protection LD50 Lethal Dose for 50% of the Test Animals 2 [Note: MDH staff have made limited revisions to this report for the sake of clarity, correction, or formatting. This report does not represent official agency policy but may be used to inform future work.] LOAEL Lowest Observed Adverse Effect Level LTD Lowest Therapeutic Dose OPI Organophosphate Insecticide OSHA Occupational Safety and Health Administration OTC Over-the-counter MA Massachusetts MCL Maximum Contaminant Level MDH Minnesota Department of Health MI DEQ Michigan Department of Environmental Quality MOE Margin of Exposure MSDS Material Safety Data Sheet MTD Maximum Tolerated Dose NCI National Cancer Institute NIEHS National Institute of Environmental Health Sciences NOAEL No Observable Adverse Effect Level NTP National Toxicology Program NRC National Research Council NSRL No Significant Risk Level NY New York OECD Organization for Economic Co-operation and Development OSHA Occupational Safety and Health Administration 3 [Note: MDH staff have made limited revisions to this report for the sake of clarity, correction, or formatting. This report does not represent official agency policy but may be used to inform future work.] PAH Polycyclic Aromatic Hydrocarbons PCBs Polychlorinated Biphenyls PCDD/F Polychlorinated dibenzo-p-dioxin/ Polychlorinated dibenzofuran PFOA Perfluorooctanoic acid PFOS Perfluorooctane sulfonate POC Principal Organic Contaminants QA/QC Quality Assurance/Quality Control QSAR Qualitative/Quantitative Structure Activity Relationships RAA Risk Assessment Advice REACH Registration, Evaluation, Authorization and Restriction of Chemical Substances RfD Reference Dose RSC Relative Source Contribution Factor SF Slope Factor TCDD 2,3,7,8-Tetrachlorodibenzo-p-dioxin TD10 Toxic Dose for 10% of the Test Animals TD50 Toxic Dose for 50% of the Test Animals TK Thymidine Kinase TOC Total Organic Carbon TTC Threshold of Toxicological Concern UCL Upper Confidence Limit UDS Unscheduled DNA Synthesis UF Uncertainty Factor 4 [Note: MDH staff have made limited revisions to this report for the sake of clarity, correction, or formatting. This report does not represent official agency policy but may be used to inform future work.] US EPA US Environmental Protection Agency WHO World Health Organization WRF WateReuse Research Foundation VSD Virtual Safe Dose 5 [Note: MDH staff have made limited revisions to this report for the sake of clarity, correction, or formatting. This report does not represent official agency policy but may be used to inform future work.] EXECUTIVE SUMMARY Over the past several years a variety of non-environmentally regulated chemicals have started to be detected in both groundwater and surface water throughout the US, including Minnesota. As a group, these chemicals have been termed “Contaminants of Emerging Concern” (CEC). The majority of these CECs have been shown to be pharmaceuticals, personal and household care product ingredients and endocrine disrupting compounds such as birth control product chemicals. The Minnesota Department of Health (MDH) has formed a program within the Division of Environmental Health to specifically address these water contaminants (CEC Program). One effort by this Program is a Clean Water, Land and Legacy Amendment-funded special project entitled “Evaluating, Testing, and Reporting of Alternative Risk Assessment Methods.” The goal of this project is to present defensible alternative risk assessment methodologies for deriving water quality advisory criteria for CECs. Alternative risk assessment methodologies were sought for the CEC Program because of: • the large number of CECs being detected each year (due to both increased analytical sensitivity and a current focus on these chemical classes), • a paucity of requisite toxicological information on CECs that is necessary to develop drinking water guidance (HRL/HBV/RAA) by the traditional risk assessment approach, and • the amount of time and effort required to perform a traditional toxicity assessment on each chemical. The initial phase of this special project focused on identifying candidate alternative risk assessment methods. The criteria used for selecting these alternative methods was that they be capable of deriving ‘safe harbor’ criteria and as a group be able to address the majority of CECs that have been reported in drinking water, regardless of the composition of their existing toxicity databases. A total of ten candidate alternative risk assessment methods were identified in this initial project phase (see Chapter 2). These methods are: • As Low As Reasonably Achievable Approach • LD50 Extrapolation Approach • Margin of Exposure Approach • Lowest Therapeutic Dose Approach • Percent Sample Mass Approach • Percentile Approach • Quantitative/Qualitative Structure-Activity Relationship Approach • Surrogate Compound Approach • Threshold of Toxicological Concern Approach • Virtual Safe Dose Approach 6 [Note: MDH staff have made limited revisions to this report for the sake of clarity, correction, or formatting. This report does not represent official agency policy but may be used to inform future work.] The second phase of this project involved a technical evaluation of each of these candidate methods (see Chapter 3). Each evaluation began with a brief description of the method, followed by a summary of any background information on the procedure (e.g., how and where it had been used previously). This introductory information was then followed by a quantitative method analysis, when possible, and finally a strengths and limitations analysis with respect to its usefulness to the CEC Program. Each evaluation concluded with a recommendation regarding whether or not the method should be retained for further evaluation by the CEC Program. Out of the original 10 candidate alternative risk assessment methods, six have been recommended for further evaluation in the CEC Program. The six potential CEC methods were then placed in a proposed CEC Program Alternative Methods Decision Tree in order to provide a project strategy overview (see Figure 4). The Decision Tree is a three- step process that will assign each CEC to one of seven chemical categories: • Category A: CEC with unknown chemical structure • Category B1: Non-pharmaceutical CEC; Genotoxin/Carcinogen • Category B2: Non-pharmaceutical CEC; Non-genotoxin/Non-carcinogen • Category B3: Non-pharmaceutical CEC; Unknown Genotoxin/Carcinogen Status • Category C1: Pharmaceutical CEC; Genotoxin/Carcinogen • Category C2: Pharmaceutical CEC; Non-genotoxin/Non-carcinogen • Category C3: Pharmaceutical CEC; Unknown Genotoxin/Carcinogen Status Each of the seven categories has its own unique complement of these alternative risk assessment methods from which the appropriate safe harbor criteria would be derived. Table ES-1 presents this listing of methods for each of the Decision Tree categories. 7 [Note: MDH staff have made limited revisions to this report for the sake of clarity, correction, or formatting. This report does not represent official agency policy but may be used to inform future work.] Table ES-1: Listing of Alternative Risk Assessment Methods by Decision Tree Category Decision Tree Category Retained Method A Unidentified CEC Threshold of Toxicological Concern Approach Percentile Approach Non-pharmaceuticals B1 Genotoxins/Carcinogens Threshold of Toxicological Concern Approach Virtual Safe Dose Approach Percentile Approach B2 Non-genotoxins/non Threshold of Toxicological Concern Approach carcinogens LD50 Extrapolation Approach Percentile Approach B3 Genotoxicity/carcinogenicity QSAR/surrogate Approach undetermined Threshold of Toxicological Concern Approach Percentile Approach Pharmaceuticals C1 Genotoxins/carcinogens Threshold of Toxicological Concern Approach Virtual Safe Dose Approach Percentile Approach C2 Non-genotoxins/non Threshold of Toxicological Concern Approach carcinogens Lowest Therapeutic Dose Approach Percentile Approach C3 Genotoxicity/carcinogenicity QSAR/surrogate Approach undetermined Threshold of Toxicological Concern Approach Percentile Approach There