REDUCING LEAD IN DRINKING WATER: A BENEFIT ANALYSIS \ Ronnie Levin Office of Policy, Planning and Evaluation U.S. Environmental Protection Agency EPA-230-09-86-019 Draft Final Report December 1986 (revised Spring 1987) ACKNOWLEDGEMENTS Many people contributed to the publication of this document: This analysis would never have been undertaken without Joel Schwartz. This document would not have been published without the help and encouragement of J'eanne Briskin and Michael B. Cook. Much appreciation also to J. Michael Davis (ECAO/ORD), Brendan Doyle (OPA/OPPE), Lester Grant (ECAO/ORD), Peter Karalekas (Region I), Peter Lassovszky (ODW/OW), James w. Patterson (Illinois Institute of Technology), Michael Schock (Illinois State Water Survey), and Ethel Stokes (EPA) -- who consistently provided more help than they ever wanted to. Thanks also to Gene Rosov (WaterTest Corporation). Finally, special thanks to the many people who repeatedly reviewed successive drafts of this report. TABLE OF O)NTENTS PAGE CEAPl'ER I: . INTRODUCTION I .A. BACKGROUND INFORMATION I-1 I. B. SlMMARY OF REFORT I-2 I. B 1. The Occurrence of Lead in I-5 Public Drinking Water I.B.2. Benefits of ReducinJ Children's I-1O Exposure to Lead I.B.3. Blood-Pressure-Related Benefits I-16 and other Adult Health Effects I.B.4. Benefits of Reduced Materials Darra.ge I-19 I. B. 5. Summary of Annual Benefits of Reduced I-22 Lead in Drinkinq Water I.C. OOS'IDN CASE S'IUDY I-25 CHAPI'ER II: OCCURRENCE OF IEAD IN DRINKING WATER II .A. SOURCES OF LEAD IN DRINKIID WATER II-2 II.A.1. Variables Affecting Lead Levels in Drinking Water II-3 II.A.La. Key Water Parameters Affecting the Solubilicy of Lead II-4 II.A. 1.b. Lead Solder II-6 II.A.1.c. 'Lead Pipes II-1O II .A. 1. d. Other Potential Sources of Lead II-1O II.A.Le. Other Factors Relating to Lead Contamination Lev~ls II-12 II.A.1.f. Surrarary II-13 II.A. 2. Prevalence of Lead Materials in Distribution Systems II-14 Table of Contents PAGE II.B. mTA ON THE OCCURRENCE OF LEAD IN DRINKING WATER II-16 II.B.l. Patterson Study/CUlligan Data on Tap Water II-18 II.B.l.a. Consistency with Other Data II-21 II.B.l.b. Potential Biases in the Data II-25 II.B.l.c. Alternative Analysis of Potential Exposure to Lead in Drinking Water II-32 II.B.2. Lead Contamination in New Hrusing II-38 II.C. ESTIMATED EXPOSURE TO LEAD IN U.S. TAP WATER II-41 II.C.l. Uncertainties and Assurrptions in the Analysis II-42 II.C.2. Calmlations of Exposure to Lead in Drinking Water II-54 II.C.2.a. Estirrate of Exposure to Lead in Drinking Water to Inhabitants of New ~ousing II-55 II.C.2.b. Estirrate of Exposure to Lead in Drinking Water to Inhabitants of Older Hrusing II-57 II.C.2.c. Total Estirrated Exposure to Lead in Drinking Water II-58 CHAPI'ER III: BENEFITS OF REDUCING CHILDREN'S EXPOSURE 'ID LEAD III.A. PATHOPHYSIOI.OOICAL EFFECTS III-6 III.A. 1. Effects of Lead on Pyrimidine Metabolism III-11 III.A.2. Effects on Heme Synthesis and Related Hematological Processes III-11 III.A.2.a. Mitochondrial Effects III-12 III.A.2.b. Heme Synthesis Effects III-12 III.A. 3. Lead' s Interference with Vitamin D Metabolism and Associated Physiological Processes III-13 Table of Contents PAGE III.A.4. Stature Effects III-17 III.A.4.a. Effects of Lead on Fetal GrCMth III-18 III.A.4.b. Effects of Lead on Post-Natal Growth III-.20 III.A.4.c. Sumrra:ry of Stature Effects III-26 III. B. NEUROI'0XIC EFFECTS OF LEAD EXFOSURE III-28 III. B .1. Neurotoxicity at Elevated Blood-Lead Levels III-28 III.B.2. Neurotoxicity at Lo.rler Blood-Lead Levels III-31 III.B.2.a. Cognitive Effects of Lo.rler Blood-Lead Levels III-34 III.B.3. The Magnitude of Lead 's Inpact on IQ III-40 III.C. FETAL EFFEcrs III-42 III.C.1. Assessing the &.nefi,ts of Reduced III-44 Fetal Exposure to Lead III.D. M:>NETIZED ESTIMATES OF OULDREN'S HEALTH BENEFITS III-49 III.D.1. Reduced Medical Costs III-SO III.D.2. Costs Associated with Cognitive Damage III-54 III.D.2.a. Corrpensatory Education III-55 III.D.2.b. Effect U[:on Future Earnings III-56 III.D.3. Sumnary of Monetized Benefits III-60 III.E. VALUING HEALTH EFFECI'S: CAVEATS AND LIMITATIONS III-62 III. F. Sl.M1ARY OF ANNUAL MJNETIZED AND N0N--M'.:>NEI'IZED III-67 OIILDREN'S HEALTH BENEFITS Table of Contents PAGE CHAPl'ER N: HEALTH BENEFITS OF REDUCING LEAD: ADULT ILLNESSES rv .A. THE REf.ATIONSHIP BEIWEEN BLOOD LEAD LEVELS AND BLO'.)D PRESSURE rv-2 rv.A. 1. Epidemiological Studies of Blood lead Levels IV-3 arrl :Efypertension IV .A.La. Occupational Studies IV-4 rv.A. 1.b. 01::servational Studies IV-5 IV.A.Le. Pcpulation Studies IV-7 rv.A.2. Mecnanisms Potentially Underlying lead-Induced Hypertension Effects IV-16 IV.A.2.a. Role of Disturbances in Ion TransfX)rt by Plasma Membranes rv-17 IV .A. 2. b. Role of Renin-Angiotensin in Control of Blood Pressure rv-18 and Fluid Balance rv.A.2.c. Effecc.s of Lead on Vascular Reactivicy IV-22 Iv..A.2.d. Effects of Lead on Cardiac M.lscle rv-23 rv.A.2.e SUrma:ry of Lead-Related Effects on the rv-25 Cardiovascular System IV .A. 3. Cardiovascular Disease Rates and Water Hardness IV-26 IV.A.3.a Studies of Cardiovascular Disease and Water Hardness IV-27 rv.A.3.b. Lead, Soft Water and cardiovascular Disease IV-30 IV.A.4. Benefits of Reduced Cardiovascular Disease: Reductions in Hypertension and Related Morbidicy and Mortalicy rv-32 IV.A.4.a. Ifypertension rv-35 rv.A.4.b. Myocardial Infarctions, Strokes, and Deaths rv-35 IV.B. LEAD'S EFFECTS UIDN REPRODUCTIVE FUNCI'ION N-40 IV.B.l Est:inatir:g the Population At-Risk for Female Reproductive Effects IV-43 Table of Contents PAGE IV.C. MJNEI'IZED ESTIMATES OF ADULT HEALTH BENEFITS: REDUCED CARDIOVASOJIAR DISEASE RISK IN MEN IV-45 IV. C. l. Hypertension IV-46 IV.C.2. Myocardial Infarctions IV-47 IV.C.3. Strokes IV-51 IV .C.4. Mortality IV-53 IV. C. 5. Sumrra:ry of Annual Monetized Benefits of Reduced cardiovascular Disease IV-54 IV .D. VALUING HEALTH EFFECTS: CAVEATS AND LIMITATIONS IV-56 IV.E. SUMMARY CF ANNUAL MONEI'IZED AND NONMJNETIZED ADULT HEALTH BENEFITS OF REDUCING EXroSURE TO LEAD IN DRINK[NG WATER IV-6O CHAPI'ER V: BENEFITS FROM REDUCED MATERIALS mMAGE V .A. THE CHARACI'ERISTICS OF AGGRESSIVE WATER V-4 V.A.l. Parameters of Water Affecting Corrosivity V-5 ,,~, V.A.2. The Electroc:nemistry 0£ Corrosivity V-8 V.A.3. Types of Corrosion V-9· V.A.4. Corrosion Indices V-1O V.A.5. Plurrbosolvency and Other Factors Detennining Lead Levels in Drinking Water V-12 V.B. DAMAGE TO PUBLIC SYSTEMS FROM INTERNAL O)RRQSION V-15 / V.B.l. Occurrence of Corrosive Water in the United St~tes V-15 V .B. 2. Corrosion Damage V-2O V.B.3. Estirrating the Anrual Costs of Corrosive Water V-22 V.B.4. Monetized Benefits of Reduced Corrosion Damage V-29 BIBLIOGRAPHY APPENDIX A: BOSTON CASE S'IUDY LIST OF TABLES PAGE CHAP1'ER I: TABLE I-1 SUbstances Included in the 1985 Prcposed I-3 National Prirrary Drinking Water Regulations TABLE I-2 Estirrates of Annual Per Capita Corrosion I-21 Damage TABLE I-3 Sumrrary of Estirrated Annual Monetized I-23 Benefits of Reducing Exposure to Lead fran 50 ug/1 to 20 ug/1 (1985 dollars) for Sample Year 1988 TABLE I-4 Surmary of Estirrated Annual Non-Monetized I-24 Benefits of Reducing Exposure to Lead frcm 50 ug/1 to 20 ug/1 for Sample Year 1988 aJAPI'ER I I: TABLE II-1 Distribution of Culligan Data II-22 {Patterson, 1981) TABLE II-2 M.micipal Water Samples and Population II-30-31 Percentages fra:n Culligan/Patterson Study (Patterson, 1981) TABLE II-3 Lead Contamination Levels in Tap Water by II-39 Age of Plumbing (Field Studies) TABLE II-4 Percentages of Samples Exceeding 20 ug/1 II-44 of Lead at Different pH Levels, by Age of Hcuse Lisr OF TABLES PAGE CHAPl'ER III: TABLE III-1 Blood Lead Levels of Children in III-8 the United States 1976-80 TABLE III-2 Percent of Children Requiring Chelation Therapy III-52 TABLE III-3 Est:inated Anrrual Benefits of Reduced IQ Danage by Using Changes in Expected Future Lifetirre Earnings for Sarcple Year 1988 III-59 TABLE III-4 M:Jnetized Anrrual Benefits of Reducing Children's Exposure to lead Using Alternative Methods for Sarcple Year 1988 III-61 TABLE III-5 SUimary of Annual Monetized and Non-nonetized Children's Health Benefits of Reducing lead in Drinking Water for Sarcple Year 1988. III-68 CHAPl'ER IV: TABLE IV-1 Benefits of Reducing Strokes IV-52 TABI.E IV-2 Sunmary of Anrrual Monetized Blood­ Pressure Related Benefits of r.o.,,e:i:-ed. MCL for Sarcple Year 1988 IV-;-55 TABLE IV-3 SUima.ry of Annual Monetized and Non­ IV-62 M:Jnetized Health Benefits of lowered MCL for Sample Year 1988 rnAPI'ER V: TABLE V-1 Est:inate of Anrrual Per Capita Corrosion Damage V-30 LIST OF FIGURES PAGE CHAPI'ER III: FIGURE III-1 Mllti-organ Irrpa.cts of Lead's Effects on thc9 Heme Pool III-2 FIGURE III-2 Surme.:r:y of Io,,,est Observed Effect Levels for Key Lead-induced Health Effects in Children III-3 FIGURE III-3 Relationship of Blood Lead Level to Weight in Children Aged Oto 7 III-24 FIGURE III-4 Relationship of Blood Lead Level to Height in Children Aged Oto 7 III-25 FIGURE III-5 Flar, Diagram of Medical Protocols for Children with Blood Lead Levels above 2s·ug/dl III-51 CHAPI'ER N: FIGURE N-1 Adjuste:l Rates of Death and Heart Attacks N-37 versus Blood Pressure: Framingham Data CHAPI'ER V: FIGURE V-1 1962 U.S.