MERCURY, ARSENIC AND SELENIUM IN CHANNEL CATFISH CAUGHT IN SOUTHWESTERN PENNSYLVANIA; IMPLICATIONS FOR COAL-FIRED POWER PLANT EMISSION SOURCE IDENTIFICATION AND FISH CONSUMPTION SAFETY by Yan Liu BS. Env Eng, Tongji University, China, 2001 Submitted to the Graduate Faculty of Environmental and Occupational Health Department Graduate School of Public Health in partial fulfillment Of the requirements for the degree of Master of Public Health University of Pittsburgh 2007 UNIVERSITY OF PITTSBURGH Graduate School of Public Health This thesis was presented by Yan Liu It was defended on July 30, 2007 and approved by Thesis Advisor: Conrad D. Volz; DrPH, MPH Assistant Professor Department of Environmental and Occupational Health, Graduate School of Public Health, Scientific Director, Center for Healthy Environments and Communities, Co-Director of Exposure Assessment, University of Pittsburgh Cancer Institute, Center for Environmental Oncology, University of Pittsburgh Committee Member: Nancy B. Sussman; PhD Assistant Professor Department of Environmental and Occupational Health, Graduate School of Public Health University of Pittsburgh Committee Member: Ravi K. Sharma; PhD Assistant Professor Department of Behavior & Community Health Sciences, Graduate School of Public Health University of Pittsburgh ii Copyright © by Yan Liu 2007 iii MERCURY, ARSENIC AND SELENIUM IN CHANNEL CATFISH CAUGHT IN SOUTHWESTERN PENNSYLVANIA; IMPLICATIONS FOR COAL-FIRED POWER PLANT EMISSION SOURCES IDENTIFICATION AND FISH CONSUMPTION SAFETY Yan Liu, MPH University of Pittsburgh, 2007 Abstract This study recruited local anglers to catch catfish from 3 locations within the Pittsburgh Pool and an upstream location on Allegheny River at Kittanning Dam to compare the As, Hg and Se levels in catfish fillet. The objectives were: to find if there exist locational differences of As, Hg and Se levels in catfish flesh; use catfish as sentinels to identify the sources of pollution; determine if any catfish had mercury levels above the EPA criterion; and assess the consumption risk for semi-subsistence anglers and their families. Local store-bought catfish are also compared with river-caught samples. Fish tissue was prepared following EPA method 3052. As and Se were analyzed by collision cell ICP-MS with calibration by standard addition methods. Mercury was analyzed by isotope dilution cold vapor ICP-MS. Data were log-transformed and analyzed by ANOVA with Tukey Post-Hoc Comparisons. There were no significant differences in As, Hg and Se concentrations among the Pittsburgh Pool catch, so we combined these data. Significantly higher levels of Hg and Se were found in Kittanning-caught fish even given significantly smaller fish sizes compared to those caught in the Pittsburgh Pool. The store-bought fish were significantly lower in As, Hg and Se than those caught in the Pittsburgh Pool. In addition, 23% of samples caught in Kittanning had higher mercury levels than the EPA criterion. Hg and Se levels in samples are significantly positively iv correlated. Using upper 95% CI of mean mercury level in Kittanning-caught catfish flesh, the maximum monthly allowable fish consumption limit for adult anglers is 4 meals, for children below 16 years old is 2 meals, and for women of childbearing age is 3 meals. Conclusions: The Hg and Se levels in catfish in Pittsburgh Rivers vary significantly by location. Fishers are exposed to higher Hg and Se levels when they eat the fish caught near Kittanning and Pittsburgh pool than bought from the fish market. Public health implications: River areas upstream from Pittsburgh may have higher mercury levels than those nearer Pittsburgh because of deposition of emissions from coal-fired power plants. Location specific fish consumption advisories are needed for local fishers. v TABLE OF CONTENTS PREFACE .................................................................................................................................... XI 1.0 INTRODUCTION................................................................................................................ 1 1.1 BACKGROUND .................................................................................................. 3 2.0 WHY DO WE STUDY ARSENIC, MERCURY AND SELENIUM .............................. 5 2.1 MERCURY, ARSENIC AND SELENIUM IN ENVIRONMENT ................. 5 2.2 TOXICOLOGY PROFILE OF MERCURY, ARSENIC AND SELENIUM 9 2.2.1 Mercury ...................................................................................................... 9 2.2.2 Arsenic ...................................................................................................... 10 2.2.3 Selenium .................................................................................................... 11 3.0 JUSTIFICATION OF THE STUDY ................................................................................ 12 3.1 THE PUBLIC HEALTH SIGNIFICANCE OF EATING CONTAMINATED FISH ................................................................................................. 12 3.2 CATFISH CAN ACT AS A BIO-MONITORING MODEL ......................... 12 3.3 LOCAL ANGLERS REGULARLY CATCH FISH IN PITTSBURGH’S RIVERS, CONSUME THEM AND ARE POTENTIALLY EXPOSED TO AS, HG AND SE 13 3.4 HYPOTHESIS ................................................................................................... 14 3.5 OBJECTIVES .................................................................................................... 15 vi 4.0 METHODS ......................................................................................................................... 17 4.1 STUDY AREA ................................................................................................... 17 4.2 COMMUNITY BASED PARTICIPATORY RESEARCH ........................... 20 4.3 SAMPLING PROCESS .................................................................................... 20 4.4 ANALYTIC METHOD ..................................................................................... 20 4.5 STATISTICAL METHOD ............................................................................... 21 5.0 RESULTS ........................................................................................................................... 23 5.1 NO DIFFERENCES BETWEEN PITTSBURGH POOL CAUGHT CHANNEL CATFISH ....................................................................................................... 23 5.2 SIGNIFICANT DIFFERENCE BETWEEN PITTSBURGH POOL, KITTANNING AND LOCAL STORE BOUGHT FISH ............................................... 25 5.3 WEIGHT AND LENGTH COMPARISONS BY LOCATIONS .................. 30 5.4 MERCURY LEVEL IN CHANNEL CATFISH CAUGHT IN KITTANNING DAM ......................................................................................................... 33 5.5 CORRELATION OF SELENIUM AND MERCURY ................................... 34 6.0 A RISK ASSESSMENT FOR SEMI-SUBSISTENCE ANGLERS AND THEIR FAMILIES’ EXPOSURE TO MERCURY THROUGH INGESTION OF CATFISH FROM KITTANNING DAM ..................................................................................................... 36 7.0 DISCUSSION ..................................................................................................................... 44 8.0 CONCLUSIONS ................................................................................................................ 49 9.0 PUBLIC HEALTH IMPLICATIONS ............................................................................. 50 vii APPENDIX A RISK ASSESSMENT FOR SUBSISTENCE FISHERS’ EXPOSURE TO METHYLMERCURY FROM CONSUMPTION OF CATFISH CAUGHT FROM KITTANNING DAM .................................................................................................................. 51 BIBLIOGRAPHY ....................................................................................................................... 62 viii LIST OF TABLES Table 1. Concentrations of As and Hg in Coal and Crude Oil (in μg/g) .................................. 5 Table 2. Reported Arsenic Air Concentrations in Remote Area and near coal-fired Power Plant ............................................................................................................................................... 6 Table 3. Hg, As and Se Analysis for Catfish Within Pittsburgh Pool .................................. 24 Table 4. Hg, As and Se analysis for Catfish Between Pittsburgh Pool, Kittanning Dam and Store-bought ................................................................................................................................ 26 Table 5. ANOVA Multiple Comparisons for As, Hg and Se .................................................. 27 Table 6. Weight and Total Length of Channel Catfish Caught in Different locations ........ 31 Table 7. T-test of Mean Difference of Length and Weight for Two Groups ......................... 32 Table 8. Pearson Correlations Between As, Se and Hg .......................................................... 35 Table 9. Input Parameters for Use in Risk Equations ............................................................ 39 Table 10. The ADD and Risk for Each Subgroup.................................................................... 40 Table 11. Monthly Fish Consumption Limits for Non-carcinogenic Health Endpoints – Methyl mercury ........................................................................................................................... 42 ix LIST OF FIGURES Figure 1. Metal Bioaccumulation in Food Chain ....................................................................... 7 Figure 2. Fate and Transport of Mercury in Environment ...................................................... 8 Figure 3. Study Area and Sampling Locations ........................................................................ 19 Figure 4. Arsenic Comparisons Among 3 Locations ............................................................... 28 Figure 5. Mercury Comparisons Among 3 Locations ............................................................. 29 Figure 6. Selenium Comparisons Among 3 Locations ............................................................ 30 Figure 7. Weight of Channel Catfish Caught in Different Locations ................................... 32 Figure 8. Length of Channel Catfish Caught in Different Locations.................................... 33 Figure 9. Mercury Levels in Catfish Caught in Kittanning Dam ........................................... 34 x