FORMATION OF IODINATED DISINFECTION BY-PRODUCTS FROM IODINATED X-RAY CONTRAST MEDIA, IOPAMIDOL, IN THE PRESENCE OF NOM AND CHLORINATED OXIDANTS. A Thesis Presented to The Graduate Faculty of The University of Akron In Partial Fulfilment of the Requirements for the Degree Master of Science Elizabeth Ann Crafton December, 2014 FORMATION OF IODINATED DISINFECTION BY-PRODUCTS FROM IODINATED X-RAY CONTRAST MEDIA, IOPAMIDOL, IN THE PRESENCE OF NOM AND CHLORINATED OXIDANTS. Elizabeth Ann Crafton Thesis Approved: Accepted: ____________________________ ____________________________ Advisor Department Chair Dr. Stephen E. Duirk Dr. Wieslaw Binienda _____________________________ ____________________________ Committee member Dean of the College Dr. Teresa J. Cutright Dr. George K. Haritos _____________________________ ____________________________ Committee member Interim Dean of Graduate School Dr. Lan Zhang Dr. Rex Ramsier ____________________________ Date ii ABSTRACT The objective of this study was to investigate the formation of iodinated disinfection by-products (iodo-DBPs) where iodinated x-ray contrast media (ICM), Iopamidol, acted as source of iodine, with respect to pH (6.5, 7.5, 8.5 and 9.0) in the presence of natural organic matter (NOM) and chlorinated oxidant. This was achieved by varying the NOM concentration as well as iopamidol concentrations. Iodinated trihalomethane (iodo-THM) formation was highest at pH 9.0 for chlorine and at pH 6.5 for monochloramine. A considerable increase in formation was observed from pH 6.5 to 7.5 and from 8.5 to 9.0 with respect to chlorine as oxidant. Monochloramine expressed a decreasing trend from pH 6.5 to 9.0. The most predominately formed iodo-THM was dichloroiodomethane, 57.5 nM for chlorine at pH 9.0 (DOC = 2.51 mg/L-L) and 35.2 nM for monochloramine at pH 6.5 (DOC = 2.51 mg/L-L). Chloroform formation was also impacted by the introduction of iopamidol to reactor. Monochloramine produced a wider variety of iodo-DBPs at lower concentrations in comparison to chlorine. Variation of NOM proved to impact the formation of iodo-DBPs. When NOM levels were reduced to a quarter of the original capacity (2.51 – 0.63 mg/L-L) dichloroiodomethane formation doubled at pH 9.0 with respect to chlorine (110.5 nM). Monochloramine expressed a decreasing trend with respect to decreasing levels of NOM with the source water. For both oxidants, half and quarter capacity of NOM, 1.26 and 0.63 mg/L-L respectively, expressed considerably similar formation. iii Additionally, two-way analysis of variance (two way-ANOVA) tables were generated for two response variables, chloroform and dichloroiodomethane. With respect to each oxidant, iopamidol and pH were evaluated while NOM level remained constant and NOM and pH were evaluated while iopamidol remained constant. In regard to chloroform as the response variable with varied DOC, significance was yielded for both DOC (p-value of 0.0004) and pH (p-value of 0.0325) with respect to monochloramine: whereas chlorine only exhibited significance in regard to pH (p- value of 0.0052). Varied iopamidol expressed significance for both iopamidol (p- value of < 0.0001) and pH (p-value of 0.0014) with respect to monochloramine. In regard to chlorine, significance was only determined for pH (p-value of < 0.0001). With respect to dichloroiodomethane acting as the response variable amongst varied DOC, significance was determined in regard to pH for both chlorine (p-value of 0.0009) and monochloramine (p-value of 0.0012). Varied iopamidol concentration, significance was found for iopamidol for chlorine (p-value of 0.0064) and pH for monochloramine (p-value of 0.0029). While the findings of said statistical analysis were in most cases significant, considering the interaction plots and the lack of parallelism expressed, one can assume interaction between independent variables (i.e. factors). While it cannot be determined if the lack of parallelism is due to randomness or interaction, past work supports the assumption of interaction over randomness. iv ACKNOWLEDGEMENTS First and foremost, I like to thank my advisor, Dr. Stephen Duirk for numerous years of support and guidance. I would also like to thank Dr. Teresa Cutright for her continued inspiration and mentorship. I would like to thank my committee for their support throughout this work and their input, Dr. Stephen Duirk, Dr, Teresa Cutright and Dr. Lan Zhang. I would like to thank my friends/peers: Edward Machek, Nana Ackerson, Mallory Crow and Alexis Killinger. I would like to express my deepest gratitude for my parents, Jay and Diane Crafton. I would also like to thank both of my sisters, Dr. Sarah Crafton and Rachel Crafton-Stiver, for being impeccable role models whom I can always look to for support and guidance. This work is dedicated to my uncle and fellow research scientist, Dr. John Shainoff. v TABLE OF CONTENTS Page LISTS OF TABLES .................................................................................................... viii LISTS OF FIGURES .................................................................................................. xiv CHAPTER I. INTRODUCTION ...................................................................................................... 1 1.1 Background .......................................................................................................... 1 1.2 Problem Statement ............................................................................................... 6 1.3 Specific Objectives .............................................................................................. 7 II. LITERATURE REVIEW .......................................................................................... 9 2.1 Iodinated X-Ray Contrast Media ......................................................................... 9 2.2 Occurrence of ICM in Water and Wastewater ................................................... 12 2.3 Chemical Oxidation and Disinfection By-Products (DBPs) .............................. 14 2.3.1 Chemical Oxidation .................................................................................... 14 2.3.2 Disinfection By-Product Formation ............................................................ 15 2.3.3 Aqueous Chlorine Reactivity and DBP Formation..................................... 17 2.3.4 Chloraime .................................................................................................... 19 2.4. ICM Transformation and Iodo-DBPs ............................................................... 20 2.4.1 ICM Transformation ................................................................................... 21 2.4.2 Microbial Transformation ........................................................................... 21 2.5 Toxicity .............................................................................................................. 22 vi III. MATERIALS AND METHODS .................................................................................. 27 3.1 Chemicals and Reagents .................................................................................... 27 3.2 Source Water Characterization .......................................................................... 28 3.3 Experimental Methods ....................................................................................... 33 3.3.1 DBP Formation Experiments with Cleveland Source Water ...................... 34 3.4 Analytical Procedures ........................................................................................ 35 3.4.1 Disinfection By-product ............................................................................. 35 3.6 Analyses of DBPs .............................................................................................. 38 IV. RESULTS AND DISCUSSION ............................................................................ 66 4.1 Introduction ........................................................................................................ 66 4.2 Predominant Observed Trends ........................................................................... 67 4.3 Statistical Analysis ........................................................................................... 118 V. CONCLUSIONS AND RECOMMENDATIONS ............................................... 125 5.1 Introduction ...................................................................................................... 125 5.2 Conclusions ...................................................................................................... 126 5.3 Recommendations ............................................................................................ 129 REFERENCES .......................................................................................................... 131 APPENDIX ................................................................................................................ 146 vi i LIST OF TABLES Table Page 3.1: Source water characteristics from Cleveland water .............................................. 29 3.2: Florescence EEM regions proposed by Chen et al. (2003) .................................. 31 3.3: Florescence regions for Cleveland source waters, 1 mg/L C ............................... 31 3.4: Oven temperature programming for THMs and HANs analysis on GC/μECD ... 38 3.5: Oven temperature programming for HAAs analysis on GC/μECD ..................... 39 3.6: Limit of quantification (LOQ) for the detection of DBPs .................................... 65