Body Fluid Analogues and Personal Care Products As Potential Dbp Precursors

BODY FLUID ANALOGUES AND PERSONAL CARE PRODUCTS AS POTENTIAL DBP PRECURSORS

Zhen Wang

A thesis submitted in conformity with the requirements for the degree of Master of Applied science Civil Engineering University of Toronto

Zhen Wang

Master of Applied Science

Department of Civil Engineering University of Toronto

2011

Abstract

Disinfection byproducts (DBPs), such as organic chloramines, THMs, HAAs, and nitrosamines, are formed during mandatory disinfection processes in drinking water treatment. Many of these DBPs have been shown to be potentially carcinogenic. Extensive research has been conducted on the occurrence and formation of these DBPs. However, there has been limited research on their relationships with each other, which may be important for the understanding of their formation mechanisms, and the nature of their precursors is still relatively unknown. Ultimately, this information will be key for the development of possible improvements in treatment technologies.

Results of this study improve the understanding of DBP formation in swimming pool water. Some BFAs and PCP additives were identified as potential DBP precursors. Influence of BFAs and PCP additives on DBP formation in swimming pool water was also illustrated. Results provided feasible strategies to minimize DBP formation while maintaining the efficiency of disinfection.

Acknowledgments

Sincerely, I would like to thank my supervisor Dr. Susan A. Andrews for her patience, encouragement, effort and advice throughout the last two and half years. I will not be able to succeed this without your help.

I would also like to thank my parents, my wife and my sister's family. They have always been supportive during my life.

I would like to extend my thanks to pool managers and pool supervisors who have supported in this study with water samples.

Finally, I would like to thank the Drinking Water Research Group in the department of Civil Engineering. It is a harmonious family and everyone is ready to help.

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Table of Contents

BODY FLUID ANALOGUES AND PERSONAL CARE PRODUCTS AS

POTENTIAL DBP PRECURSORS ...... i

Acknowledgments ...... iii

Table of Contents ...... iv

List of Tables ...... x

List of Figures ...... xiii

Chapter 1 Introduction ...... 1

Introduction ...... 1

1.1 Overview ...... 1

1.2 Objectives ...... 2

1.2.1 Micro-objective ...... 2

1.2.2 Macro-objective ...... 3

1.3 Thesis organization ...... 3

Chapter 2 Literature review ...... 4

Literature review ...... 4

2.1 Disinfection in drinking water ...... 4

2.1.1 Free chlorine ...... 5

2.1.2 Monochloramine ...... 6

2.2 Disinfection byproducts in drinking water ...... 9

2.2.1 Organic chloramines ...... 10

2.2.2 Trihalomethanes (THMs) and haloacetic acids (HAAs) ...... 11

2.2.3 Nitrosamines ...... 14

2.3 Regulatory standards for drinking water ...... 16

2.4 Swimming pools ...... 17

2.5 Disinfection of swimming pools ...... 18

2.6 Disinfection byproducts in swimming pools ...... 22

2.7 Regulations and methods to minimize DBP formation in swimming pool water

...... 25

2.8 Possible DBP precursors in swimming pool water ...... 26

2.8.1 Body fluid analogues (BFAs) in simulated swimming pools ...... 26

2.8.2 Personal care products (PCPs) in simulated swimming pools ...... 27

2.9 Summary of research gaps ...... 29

Chapter 3 Materials and methods ...... 30

Materials and methods ...... 30

3.1 Materials ...... 30

3.1.1 Chemical reagents and Standard materials ...... 30

3.1.1.1 Routine chemicals ...... 30

3.1.1.2 BFAs ...... 31

3.1.1.3 PCP compounds ...... 32

3.1.1.4 Pool stabilizer (cyanuric acid) and humic acid ...... 33

3.1.1.5 Chemical standards ...... 33

3.1.2 Glassware ...... 33

3.2 Methods ...... 34

3.2.1 Experimental methods ...... 34

3.2.2 Analytical methods ...... 35

3.2.2.1 Organic chloramine (HPLC) ...... 35

3.2.2.2 THMs and HAAs (GC) ...... 36

3.2.2.3 Nitrosamines (GC/MS) ...... 37

3.2.2.4 Other methods and instruments ...... 40

3.2.3 QA/QC protocol ...... 41

Chapter 4 Water characterization and preliminary tests ...... 42

Water characterization and preliminary tests ...... 42

4.1 Selection of swimming pools ...... 42

4.1.1 Indoor swimming pools ...... 42

4.1.2 Outdoor swimming pools ...... 46

4.2 Ambient water quality of swimming pools (Part I) ...... 48

4.2.1 Concentrations of DBPs in swimming pool water ...... 48

4.2.2 Discussion of typical results ...... 54

4.2.2.1 TOC and SUVA ...... 54

4.2.2.2 Organic chloramine and nitrosamines ...... 56

4.2.2.3 Discussion related to THMs and HAAs ...... 58

4.2.3 Effects of shocking treatment ...... 60

4.2.4 Comparison of indoor swimming pools versus outdoor swimming pools ...... 65

4.2.5 Summary ...... 70

4.3 Preliminary bench-scale experiment (Part II) ...... 71

4.3.1 Free chlorine demand for BFA base mix compounds and PCP additives ...... 73

4.3.2 Free chlorine breakpoint for BFAs and PCP additives ...... 78

4.3.3 Disinfection byproducts in simulated swimming pool bulk water with chlorination ..... 85

4.3.3.1 Results of DBP formation from simulated swimming pool water spiked with

subgroups of PCP additives in 5 days ...... 86

4.3.3.2 Results of DBP formation from simulated swimming pool water spiked with

individual PCP additives in 48 hours and 120 hours ...... 90

4.3.4 DBP formation potential of BFA compounds, PCP additives, cyanuric acid and humic

acid under chloramination conditions ...... 97

4.3.4.1 DBP formation potential of BFA base mix compounds, stabilizer (cyanuric acid),

and humic acid under chloramination ...... 98

4.3.4.2 DBP formation potential of PCP additives under chloramination ...... 101

4.3.5 Summary ...... 105

Chapter 5 Effects of additives on DBP formation in pool water ...... 107

Effects of additives on DBP formation in pool water...... 107

5.1 Influence of BFA base mix compounds, PCP additives, pool stabilizer and

humic acid on DBP formation in outdoor swimming pools (Part III) ...... 107

5.1.1 Influence of BFA compounds on DBP formation in outdoor swimming pool (Out3) water

matrix ...... 108

5.1.1.1 Influence on combined chlorine formation ...... 109

5.1.1.2 Influence on THM formation ...... 111

5.1.1.3 Influence on HAA formation...... 112

5.1.1.4 Influence on nitrosamine formation ...... 115

5.1.2 Influence of PCP additives on DBP formation in outdoor swimming pool (Out3) water

matrix ...... 116

5.1.2.1 Influence on combined chlorine formation ...... 117

5.1.2.2 Influence on THM formation ...... 119

5.1.2.3 Influence on HAA formation...... 120

5.1.2.4 Influence on nitrosamine formation ...... 122

5.1.3 Influence of stabilizer (cyanuric acid) and humic acid on DBP formation in outdoor

swimming pool (Out3) water ...... 124

5.1.3.1 Influence on combined chlorine formation ...... 125

5.1.3.2 Influence on THM formation ...... 126

5.1.3.3 Influence on HAA formation...... 127

5.1.3.4 Influence on nitrosamine formation ...... 128

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5.1.4 Summary ...... 129

5.2 Influence of BFA base mix compounds, PCP additives and humic acid on the

formation of DBPs in indoor pool water (Part IV) ...... 131

5.2.1 Influence of BFA base mix compounds on DBP formation in indoor swimming pool (In2)

water ...... 132

5.2.1.1 Influence on combined chlorine formation ...... 132

5.2.1.2 Influence on THM formation ...... 134

5.2.1.3 Influence on HAA formation...... 135

5.2.1.4 Influence on DMA, NMOR and NDEA formation ...... 136

5.2.2 Influence of PCP additives on DBP formation in indoor swimming pool (In2) water . 137

5.2.2.1 Influence on combined chlorine formation ...... 138

5.2.2.2 Influence on THM formation ...... 140

5.2.2.3 Influence on HAA formation...... 141

5.2.2.4 Influence on NDMA, NMOR and NDEA formation ...... 142

5.2.3 Influence of pool stabilizer (cyanuric acid) and humic acid on DBP formation in indoor

swimming pool (In2) water ...... 144

5.2.3.1 Influence on combined chlorine formation ...... 144

5.2.3.2 Influence on THM formation ...... 146

5.2.3.3 Influence on HAA formation...... 147

5.2.3.4 Influence on NDMA, NMOR and NDEA formation ...... 148

5.2.4 Summary ...... 149

Chapter 6 Conclusions ...... 151

Conclusions ...... 151

6.1 Conclusions from measurements of ambient water quality of swimming pools

...... 151

6.2 Conclusions from preliminary bench-scale tests ...... 153

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6.3 Conclusions from real swimming pool water tests ...... 154

Chapter 7 Recommendations ...... 156

Recommendations ...... 156

7.1 Recommendations for future work ...... 156

7.2 Operational suggestions ...... 157

Chapter 8 Reference ...... 158

Reference ...... 158

Chapter 9 Appendix ...... 170

Appendix ...... 170

9.1 QA/QC protocol ...... 170

9.1.1 Typical calibration curves and QC charts for organic chloramine ...... 170

9.1.2 Typical calibration curves and QC charts for THMs ...... 171

9.1.3 Typical calibration curves and QC charts for HAA9 ...... 174

9.1.4 Typical calibration curves and QC charts for nitrosamines ...... 180

9.2 Raw data for additional swimming pools ...... 185

9.3 Additional data for free chlorine breakpoint testing of individual BFA base mix

compounds, PCP additives, and cyanuric acid ...... 191

9.4 Results of t-tests for experiments in Chapter 5 ...... 200

List of Tables

Table 2.1-1 Chlorine reactions in drinking water treatment ...... 6

Table 2.8-1 Molecular structure of BFA components ...... 27

Table 2.8-2 Molecular structure of PCP additives ...... 28

Table 3.1-1 Grade of BFAs ...... 31

Table 3.1-2 Stock solution concentrations of BFA compounds (Judd et al., 2003) ..... 32

Table 3.1-3 Information of PCP additives...... 32

Table 3.2-1 Organic chloramine analysis – HPLC operating conditions ...... 36

Table 3.2-2 Trihalomethane analysis – Gas Chromatograph operating conditions ..... 37

Table 3.2-3 HAA9 analysis– Gas Chromatograph operating conditions ...... 37

Table 3.2-4 Nitrosamine analysis-GC/MS operating condition ...... 39

Table 3.2-5 Nitrosamines and their corresponding retention time ...... 39

Table 3.2-6 Method Detection Limits (ng/L) of nitrosamines on GC/MS ...... 39

Table 3.2-7 Other analytical methods used in this thesis ...... 40

Table 4.1-1Operational parameters of selected indoor swimming pools ...... 44

Table 4.1-2Operational parameters of selected outdoor swimming pools ...... 47

Table 4.2-1 Measurements of indoor swimming pool (In2) on campus ...... 50

Table 4.2-2 Measurements of community indoor swimming pool (In4) ...... 51

Table 4.2-3 Measurements of community outdoor swimming pool (Out1) ...... 52

Table 4.2-4 Measurements of outdoor hot tub (Out3) ...... 53

Table 4.2-5 Measurements of indoor swimming pool (In1) water before and after shocking treatment ...... 61

Table 4.3-1 Stock solution concentrations of BFA compounds (Judd et al., 2003) ..... 71

Table 4.3-2 Calculation of TOC for BFA base mix compounds and PCP additives in mg/L ...... 72

Table 4.3-3 Measurements of free chlorine and total chlorine in BFA simulated swimming pool water spiked with PCP additives ...... 75

Table 4.3-4 Free chlorine residual after 3 hours in different groups of BFA and BFA+PCP compounds in simulated swimming pool water ...... 79

Table 4.3-5 Free chlorine residual after 24 hours in different groups of BFA and BFA+PCP compounds simulated swimming pool water ...... 80

Table 4.3-6 Breakpoint measurements for BFA compound #1 (ammonium chloride) 81

Table 4.3-7 Breakpoint measurements for BFA compound #3 (histidine) ...... 82

Table 4.3-8 Breakpoint measurements for BFA compound #7 (creatinine) ...... 83

Table 4.3-9 Breakpoint measurements for PCP additive A1 (diethanolamine) ...... 84

Table 4.3-10 Breakpoint measurements for PCP additive A4 (triethanolamine) ...... 84

Table 4.3-11 Results of DBP formation in simulated swimming pool water spiked with subgroups of PCP additives (5 day reaction) ...... 87

Table 4.3-12 Results of free and combined chlorine in simulated swimming pool water

spiked with PCP additive ...... 92

Table 4.3-13 Results of THMs, HAAs and nitrosamines in simulated swimming pool water spiked with PCP additive ...... 93

Table 5.1-1 Concentrations of BFAs used for Out3 pool water experiments ...... 109

Table 5.1-2 Concentration of free and combined chlorine in outdoor swimming pool (Out3) spiked with BFA compounds #2 to #7 individually ...... 110

Table 5.1-3Concentration of THMs in outdoor swimming pool (Out3) spiked with BFA compounds #2 to #7 individually ...... 112

Table 5.1-4 Concentration of HAA9 and main species in outdoor swimming pool (Out3) spiked with BFA compounds #2 to #7 individually ...... 114

Table 5.1-5 Concentration of nitrosamines (NDEA/NDBA) in outdoor swimming pool (Out3) spiked with BFA compounds #2 to #7 individually ...... 115

Table 5.1-6 Concentration of free and combined chlorine in outdoor swimming pool (Out3) spiked with PCP additives A1 to A10 individually ...... 118

Table 5.1-7 Concentration of THMs in outdoor swimming pool (Out3) spiked with PCP additives A1 to A10 individually ...... 120

Table 5.1-8 Concentration of HAA9 and main species in outdoor swimming pool (Out3) spiked with PCP additives A1 to A10 individually ...... 121

Table 5.1-9 Concentration of nitrosamines (NDMA/NDEA/NDBA) in outdoor swimming pool (Out3) spiked with PCP additives A1 to A10 individually ...... 123

Table 5.2-1Concentrations of BFAs used for In2 pool water experiment ...... 132

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List of Figures

Figure 2.1-1 Typical breakpoint curve for the chlorination of ammonia at pH 8 ...... 8

Figure 2.1-2 Typical breakpoint curve for the chlorination of ammonia and organic amines ...... 9

Figure 4.1-1 General schematic of swimming pool treatment processes ...... 45

Figure 4.2-1 Relation between TOC value and bather load of indoor swimming pool In2 ...... 54

Figure 4.2-2 Comparison of TOC values between indoor pool In1 and In2 ...... 55

Figure 4.2-3 Relation between SUVA value and bather load of indoor swimming pool (In2) ...... 56

Figure 4.2-4 Bather loads of indoor swimming pool (In2) on sampling days ...... 57

Figure 4.2-5 Concentration of nitrosamines (NDMA, NDBA, NDEA) along with concentration of organic chloramines in indoor swimming pool (In2) 58

Figure 4.2-6 Concentration of THMs along with bather load of indoor swimming pool (In2) ...... 59

Figure 4.2-7 Concentration of, MCAA, DCAA, TCAA, and HAA9 along with bather load in indoor swimming pool (In3) ...... 59

Figure 4.2-8 Effects of shocking treatment on organic chloramines in indoor swimming pool (In1) ...... 63

Figure 4.2-9 TOC before and after shocking treatment in indoor swimming pool (In1) ...... 63

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Figure 4.2-10 THMs before and after shocking treatment in indoor swimming pool (In1) ...... 63

Figure 4.2-11 HAA9 before and after shocking treatment in indoor swimming pool (In1) ...... 64

Figure 4.2-12 NDMA before and after shocking treatment in indoor swimming pool (In1) ...... 64

Figure 4.2-13 Bather load per 1000 liter pool water of different types of swimming pools (outdoor pools 1-3, indoor pools 1-5) ...... 66

Figure 4.2-14 TOC value comparison of different types of swimming pools (outdoor pools 1-3, indoor pools 1-5) ...... 66

Figure 4.2-15 THM value comparison of different types of swimming pools (outdoor pools 1-3, indoor pools 1-5) ...... 67

Figure 4.2-16 HAA9 value comparison of different types of swimming pools (outdoor pools 1-3, indoor pools 1-5) ...... 68

Figure 4.2-17 SUVA value comparison of different types of swimming pools (outdoor pools 1-3, indoor pools 1-5) ...... 69

Figure 4.2-18 NDMA value comparison of different types of swimming pools (outdoor pools 1-3, indoor pools 1-5) ...... 70

Figure 4.3-1 Free chlorine degradation in BFA simulated swimming pool water with/without PCP additives ...... 76

Figure 4.3-2 Total chlorine degradation in BFA simulated swimming pool water with/without PCP additives ...... 77

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Figure 4.3-3 Combined chlorine formation in BFA simulated swimming pool water with/without PCP additives ...... 77

Figure 4.3-4 Free chlorine residual after 3 hours in different groups of BFA and BFA+PCP compounds simulated swimming pool water ...... 79

Figure 4.3-5 Free chlorine residual after 24 hours in different groups of BFA and BFA+PCP compounds simulated swimming pool water ...... 80

Figure 4.3-6 Breakpoint curve for BFA compound #1 ammonium chloride of 2 mg/L with time of 1.5 hours ...... 81

Figure 4.3-7 Breakpoint curve for 1.21 mg/L BFA compound #3 (histidine) ...... 83

Figure 4.3-8 Breakpoint curve for 1.8 mg/L BFA compound #7 (creatinine) ...... 83

Figure 4.3-9 Breakpoint curve for 1 mg/L PCP additive A1 (diethanolamine) ...... 84

Figure 4.3-10 Breakpoint curve for 1 mg/L PCP additive A4 (triethanolamine) ...... 85

Figure 4.3-11 Concentration of combined chlorine formed in simulated swimming pool water spiked with subgroups of PCP additives within 5 days ...... 88

Figure 4.3-12 Concentration of TTHM following 5 days of reaction of simulated swimming pool water spiked with subgroups of PCP additives ...... 89

Figure 4.3-13 Concentration of HAA9 following 5 days of reaction of simulated swimming pool water spiked with subgroups of PCP additives ...... 89

Figure 4.3-14 Concentration of NDMA following 5 days of reaction of simulated swimming pool water spiked with subgroups of PCP additives ...... 90

Figure 4.3-15 Concentration of free chlorine in simulated swimming pool water spiked with PCP additives individually at 48 hours and 120 hours ...... 91

Figure 4.3-16 Concentration of combined chlorine individually at 48 hours and 120 hours ...... 92

Figure 4.3-17 Concentration of THMs in simulated swimming pool water spiked with PCP additives individually at 48 hours and 120 hours ...... 94

Figure 4.3-18 Molecular structure of PCP additive A6 cetyltrimethylammonium chloride ...... 94

Figure 4.3-19 Concentration of HAA9 in simulated swimming pool water spiked with PCP additives individually at 48 hours and 120 hours ...... 95

Figure 4.3-20 Molecular structure of PCP additive A3 nitrilotriacetic acid ...... 95

Figure 4.3-21 Concentration of NDMA in simulated swimming pool water spiked with PCP additives individually at 48 hours and 120 hours ...... 96

Figure 4.3-22 Concentration of NDBA in simulated swimming pool water spiked with PCP additives individually at 48 hours and 120 hours ...... 97

Figure 4.3-23 Concentration of monochloramine in samples of MilliQ water spiked with BFA compounds (#2 to #7), cyanuric acid (30 mg/L), and humic acid (1 mg/L ) while initial monochloramine was 2.9 mg/L ...... 99

Figure 4.3-24 Concentration of total chlorine in samples of MilliQ water spiked with BFA compounds, cyanuric acid (30 mg/L), and humic acid (1 mg/L ) while initial monochloramine was 2.9 mg/L ...... 99

Figure 4.3-25 Concentration of combined chlorine in samples of MilliQ water spiked with BFA compounds, cyanuric acid (30 mg/L), and humic acid (1 mg/L ) while initial monochloramine was 2.9 mg/L (sample of cyanuric acid was measured as free chlorine) ...... 100

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Figure 4.3-26 Concentration of NDEA, NDMA, and NDBA in samples of MilliQ water spiked with BFA compounds, cyanuric acid (30 mg/L), and humic acid (1 mg/L ) while initial monochloramine was 2.9 mg/L ...... 101

Figure 4.3-27 Concentration of total chlorine in samples of MilliQ water spiked with 1 mg/L of PCP additives while initial monochloramine was 2.9 mg/L 102

Figure 4.3-28 Concentration of monochloramine in samples of MilliQ water spiked with 1 mg/L of PCP additive while initial monochloramine was 2.9 mg/L ...... 102

Figure 4.3-29 Concentration of calculated combined chlorine in samples of MilliQ water spiked with 1 mg/L of PCP additive while initial monochloramine was 2.9 mg/L ...... 103

Figure 4.3-30Molecular structure of PCP additive A1 diethanolamine ...... 103

Figure 4.3-31Molecular structure of PCP additive A2 Padimate O (NPABAO) ...... 104

Figure 4.3-32Molecular structure of A9 behentrimonium chloride ...... 104

Figure 4.3-33 NDEA, NDMA, and NDBA in MilliQ water spiked with BFA compounds, 30 mg/L cyanuric acid, and 1 mg/L humic acid while initial monochloramine of 2.9 mg/L ...... 105

Figure 5.1-1 Concentration of free chlorine in outdoor swimming pool (Out3) water spiked with BFA compounds #2 to #7 individually ...... 110

Figure 5.1-2 Concentration of combined chlorine in outdoor swimming pool (Out3) water spiked with BFA compounds #2 to #7 individually ...... 111

Figure 5.1-3 Concentration of THMs in outdoor swimming pool (Out3) water spiked with BFA compounds #2 to #7 individually ...... 112

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Figure 5.1-4 MCAA, DCAA, TCAA and HAA9 in outdoor swimming pool (Out3) water spiked with BFA compounds #2 to #7 individually ...... 114

Figure 5.1-5 Molecular structure of BFA compound #6 citric acid ...... 114

Figure 5.1-6 NDEA and NDBA in outdoor swimming pool (Out3) water spiked with BFA compounds #2 to #7 individually ...... 116

Figure 5.1-7 Concentration of free chlorine in outdoor swimming pool (Out3) water spiked with PCP additives A1 to A10 individually ...... 118

Figure 5.1-8 Concentration of combined chlorine in outdoor swimming pool (Out3) water spiked with PCP additives A1 to A10 individually ...... 119

Figure 5.1-9 Concentration of THMs in outdoor swimming pool (Out3) water spiked with PCP additives A1 to A10 individually ...... 120

Figure 5.1-10 MCAA, DCAA, TCAA and HAA9 in outdoor swimming pool (Out3) water spiked with PCP additives A1 to A10 individually ...... 122

Figure 5.1-11 NDMA, NDEA, NDBA in outdoor swimming pool (Out3) water spiked with PCP additives A1 to A10 individually ...... 123

Figure 5.1-12 Molecular structure of cyanuric acid ...... 124

Figure 5.1-13 Concentration of combined chlorine in outdoor swimming pool (Out3) water spiked with cyanuric acid and humic acid individually ...... 126

Figure 5.1-14 Concentration of free chlorine in outdoor swimming pool (Out3) water spiked with cyanuric acid and humic acid individually ...... 126

Figure 5.1-15 Concentration of THMs in outdoor swimming pool (Out3) water spiked with cyanuric acid and humic acid individually ...... 127

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Figure 5.1-16 Concentration of MCAA, DCAA, TCAA and HAA9 in outdoor swimming pool (Out3) water spiked with cyanuric acid and humic acid individually ...... 128

Figure 5.1-17 Concentration of nitrosamines (NDMA/NDEA/NDBA) in outdoor swimming pool (Out3) water spiked with cyanuric acid and humic acid individually ...... 129

Figure 5.2-1 Concentration of free chlorine in In2 pool water spiked with BFA compounds individually at time of 1.5 hours and 24 hours ...... 133

Figure 5.2-2 Concentration of combined chlorine in In2 pool water spiked with BFA compounds individually at time of 1.5 hours and 24 hours ...... 134

Figure 5.2-3 Concentration of THMs in In2 pool water spiked with BFA base mix compounds individually at time of 24 hours ...... 135

Figure 5.2-4 MCAA, DCAA, TCAA and HAA9 in In2 pool water spiked with BFA base mix compounds individually at time of 24 hours ...... 136

Figure 5.2-5 NDMA, NMOR and NDEA in In2 pool water spiked with BFA base mix compounds individually at time of 24 hours ...... 137

Figure 5.2-6 Concentration of free chlorine in (In2) swimming pool water spiked with PCP additives individually at time of 1.5 hours and 24 hours ...... 139

Figure 5.2-7 Concentration of combined chlorine in (In2) swimming pool water spiked with PCP additives individually at time of 1.5 hours and 24 hours ... 139

Figure 5.2-8 Molecular structure of PCP additive A1 diethanolamine ...... 140

Figure 5.2-9 Molecular structure of PCP additive A4 triethanolamine ...... 140

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Figure 5.2-10 Molecular structure of PCP additive A8 cocamidopropyl betaine ...... 140

Figure 5.2-11 Concentration of total THM in (In2) swimming pool water spiked with PCP additives individually at time of 24 hours ...... 141

Figure 5.2-12 MCAA, DCAA, TCAA and HAA9 in (In2) swimming pool water spiked with PCP additives individually at time of 24 hours ...... 142

Figure 5.2-13 NDMA, NMOR and NDEA in (In2) swimming pool water spiked with PCP additives individually at time of 24 hours ...... 143

Figure 5.2-14 Concentration of free chlorine in (In2) swimming pool water spiked with PCP additives individually at time of 1.5 hours and 24 hours ...... 145

Figure 5.2-15 Combined chlorine in (In2) swimming pool water spiked with PCP additives individually at time of 1.5 hours and 24 hours ...... 146

Figure 5.2-16 Concentration of TTHM (In2) swimming pool water spiked with PCP additives individually at time of 24 hours ...... 147

Figure 5.2-17 MCAA, DCAA, TCAA and HAA9 in (In2) swimming pool water spiked with PCP additives individually at time of 24 hours ...... 148

Figure 5.2-18 Concentration of NDMA, NMOR and NDEA in (In2) swimming pool water spiked with PCP additives individually at time of 24 hours .... 149

Chapter 1 Introduction

Introduction

Disinfection byproducts (DBPs), such as organic chloramines, THMs, HAAs, and nitrosamines are formed during mandatory disinfection processes in drinking water treatment. Since chloroform was first found in drinking water in 1970s, thousands of disinfection byproducts (DBPs) have been found in drinking water with the development of analytical technologies over the past decades. Some of these DBPs have been regulated with a good understanding of their formation mechanisms and suggested control processes. However, for most of the DBPs, their formation mechanisms are still uncertain and they are potentially health dangerous.

Intensive effort has been expended on the factors influencing the formation of these DBPs, such as pH, temperature, alkalinity, and natural organic matter (NOM), which, to some degree, has improved the recognition of these DBPs and promoted their regulation. However, limited research has been found to be focusing on the relationship between different classes of DBPs and their precursors (Diehl et al., 2000; Hua and Reckhow, 2008).

1.1 Overview

This thesis aimed at the relationship between different classes of DBPs and intended to find possible hints of the formation mechanisms for some emerging DBPs, such as nitrosamines. In this research, considering the fairly low concentration of DBP in drinking water, swimming pool water was used as experimental water matrix since research has shown higher DBP concentration in swimming pools (Beech et al., 1980). Normally, swimming pools use tap water as their feed water and perform similar water treatment processes (coagulation/filtration/disinfection) to drinking water treatment.

However, swimming pools have continuous loading of organic matter from swimmers and use high concentration (at least 1.0 mg/L post-breakpoint) of disinfectant. Consequently, higher concentrations of DBPs are produced.

In this study, wide range of swimming pools were selected and sampled for the measurement of physical and chemical properties as well as for the measurement of DBPs. In addition, Body Fluid Analogues (BFAs) and additives in Personal Care Products (PCPs) were selected as experimental materials. BFAs, containing key dissolved organic and inorganic compounds of human perspiration and urine, were used to simulate swimming pool water. PCP additives, such as additives used in shampoo, body lotion, cosmetic and sunscreen, were used to enhance DBP formation in swimming pool water (simulated and real).

Following sampling and measurement of real swimming pools, DBP formation potentials of BFAs and PCP additives were also investigated in simulated swimming pool water under condition of chlorination and chloramination (preliminary experiments). In addition, BFAs and PCP additives were spiked into real swimming pool water to examine their DBP formation potential and their influence on DBP formation in swimming pool water.

1.2 Objectives

Objectives included in this thesis can be considered at two levels: Micro-objectives and Macro-objectives.

1.2.1 Micro-objective

Micro-objectives included: measuring of a wide range of swimming pool water parameters and DBP concentrations in swimming pool water; examining the potential of BFAs and PCPs as DBP precursors.

1.2.2 Macro-objective

Macro-objectives included: improving the understanding on DBP formations in swimming pool water; extracting out possible operating improvements for cleaner and safer swimming pools; investigating relationships between different classes of DBPs; finding possible clues of DBP formation mechanisms.

1.3 Thesis organization

Chapter I, ―Introduction‖ provides background of DBP formation, overview and the objectives of this thesis.

Chapter II, ―Literature review‖ includes disinfection and DBP formation in drinking water as well as those in swimming pool water.

Chapter III, ―Material and methods‖ summarizes materials and experimental methods followed by QA/QC protocols.

Chapter IV, ―Water characterization and preliminary test‖ includes results from swimming pool sampling and preliminary test on BFAs and PCP additives as potential DBP precursors.

Chapter V, ―Effects of additives on DBP formation in pool water‖ depicts the influence of BFAs and PCP additives on DBP formation in real swimming pool water.

Chapter VI, ―Conclusions‖ summarizes results from this study.

Chapter VII, ―Recommendations‖ includes recommendations on future work as well as on operational suggestions.

Chapter VIII, ―Reference‖ lists the references in this thesis.

Chapter IX, ―Appendix‖ includes QA/QC data and additional results obtained in this study.

Chapter 2 Literature review

Literature review

Water should be treated before it can be used. Different types of usage of water, such as drinking water, entertainment water, agricultural and industrial water need different processes of treatment. In drinking water treatment, normally, processes of coagulation, flocculation, sedimentation, filtration, and primary and secondary disinfection should be carried out in a bid to make the treated water clean, safe, and potable.

Swimming pools, normally, use tap water as feed water and take similar water treatment processes for clean and safe pool water. However, swimming pool water encounters higher loading of organic matters and need higher concentration of disinfectant to maintain effective disinfection than those in drinking water circumstance.

2.1 Disinfection in drinking water

In order to control waterborne pathogens, disinfection is mandatory in drinking water treatment processes. Disinfection includes primary disinfection and secondary disinfection. Primary disinfection includes any pre-disinfection treatment maintaining a necessary concentration of disinfectant which achieves removal or inactivation of pathogens potentially present in the source water. Primary disinfection mainly ensures effective disinfection for the first consumer (the water treatment plant). Secondary disinfection includes any disinfection treatment supplying a sufficient concentration of disinfectant which maintains the killing or inactivation of microorganisms in the distribution system. Secondary disinfection ensures maintenance of a disinfectant residual throughout the distribution system and makes the water safe until the last consumer.

2.1.1 Free chlorine

Chlorine is widely used as a disinfectant in drinking water all around the world due to its broad-spectrum germicidal potency, low cost and well-established practices (White, 1999; McClellan et al.). It is effective against most microorganisms and able to maintain a residual in distribution system. In addition, it is easy to be combined with other disinfection methods, such as monochloramine, chlorine dioxide, ozone and ultra violet light (AWWA 1997; Montgomery Watson Harza, 2005).

Hypochlorous acid (HOCl) and hypochlorite ions OCl- are the two species of effective free chlorine. HOCl can be produced from chlorine hydrolysis as shown in Equation 2.1-1 White, 1999. On the other hand, hypochlorous acid (HOCl) is a weak acid. It dissociates according to Equation 2.1-2 to produce OCl-.

+ − Equation 2.1-1 Clퟐ + HퟐO ⇌ HOCl + H + Cl

Equation 2.1-2 HOCl ⇌ OCl− + H+

4 The equilibrium constant (Keq) of Equation 2.1-1 at 25 degrees Celsius is 3.94×10 M-1. Forward reaction is dominant direction when pH is greater than 3 in dilute solution (White, 1999).

The relative proportion of HOCl and OCl- is pH dependent (Equation 2.1-2). Given that HOCl is 80-200 times stronger than OCl-, low pH is favorable to the free chlorine disinfection effectiveness.

However, free chlorine not only performs as disinfectant but also exhibits disadvantage of producing disinfection byproducts (DBPs) when there is organic substances present in bulk water. In drinking water treatment, free chlorine can undergo several types of reactions. Significant reaction types are summarized in Table 2.1-1.

Table 2.1-1 Chlorine reactions in drinking water treatment Reaction Type Examples NH + HOCl → NH Cl + H O Ammonia substitution 3 2 2 NH2Cl + HOCl → NHCl2 + H2O 2+ + - 2Fe + HOCl + 5 H2O → 2Fe(OH)3 + 5H + Cl - - + - Inorganic oxidation NO2 + HOCl + 2 H2O → NO3 + H + Cl Br- + HOCl → HOBr + Cl- Organic reactions RCHO + HOCl → RCOOH + H+ + Cl- + - Oxidation RCOOH + HOCl → R + CO2 + H + Cl + Substitution RCOCH3 + 3HOCl → RCOOH + HCCl3 + H + 2H2O

Addition RC=CR’ + HOCl → R2C(OH)C(Cl)R’ + - - 3HOCl → 3H + 2Cl + ClO3 Decomposition + - 2HOCl → 2H + 2Cl + O2 Adapted from Dickenson (2005)

These chlorine reactions involve the modification of the oxidation state of chlorine to the relatively inert chloride form Cl- or chlorine remains in the Cl (+1) form and no oxidation occurs (i.e. substitution reactions). The oxidation ability and substitution tendency of HOCl is greater than that of OCl-.

2.1.2 Monochloramine

More and more interests are put on monochloramine as a secondary disinfectant due to its stability in distribution system and the advantage in decreasing the formation of some of the regulated disinfection byproducts, such as THMs and HAAs. Compared with free chlorine, it has a weaker oxidation potential, making it more stable than free chlorine and leading to fewer formation of regulated disinfection byproducts, such as THMs and HAAs (Krasner et al., 1989; Cowman and Singer, 1996). The amount of total organic halogen (TOX) generated in chloramination ranges from 9 to 49 percent of that in chlorination of the same types of water under the same water quality conditions (Speitel, 1999). Therefore, it provides an applicable alternative and allows utilities a better change of complying with DBP regulations.

Free chlorine reacts with ammonia rapidly in a stepwise manner to form chloramines. The simplified stoichiometry of the reactions is shown in Equations 2.1-3 to 2.1-5.

ퟔ Equation 2.1-3 NHퟑ + HOCl ⟹NHퟐCl + HퟐO 풌ퟏ = ퟓ. ퟏ × ퟏퟎ L⁄mol∙sec

ퟐ ퟒ + Equation 2.1-4 NHퟐCl + HOCl ⟹NHClퟐ + HퟐO 풌ퟐ = ퟑ. ퟒ × ퟏퟎ ∙ (ퟏ + ퟓ × ퟏퟎ [H ] L⁄mol∙sec

Equation 2.1-5 NHClퟐ + HOCl⟹NClퟑ + HퟐO 풌ퟑ = ퟏ. ퟔ L⁄mol∙sec

Monochloramine (NH2Cl), dichloramine (NHCl2), trichloramine (NCl3) will contribute to the combined chlorine residual. As indicated by the reaction kinetic constant of k1, the rate of monochloramine formation is extremely rapid at the concentrations and conditions of water treatment, where the fastest conversion of

HOCl to NH2Cl occurs at a pH 8.3-8.4 in 0.069 seconds (Kirmeyer et al. 1993).

The pH has a profound effect on the species of combined chlorine. Usually monochloramine is the only chloramine that is observed when pH values are > 7 and when the chlorine-to-ammonia molar ratio is < 1.0. At higher chlorine-to-ammonia molar ratios or at lower pH values, dichloramine is also formed. The formation rate of dichloramine increases as the pH decreases. Also, the rate of trichloramine formation increases as the pH decreases below pH 3 (a condition that is not experienced in drinking water) and no trichloramines are found above pH 7.5 regardless of the chlorine-to-ammonia ratio.

Disadvantages of chloramination include: (1) higher concentrations and longer contact times are needed for pathogen inactivation and oxidation than with free chlorine; (2) it may cause nitrification problems in distribution systems; (3) chloramination leads to the formation of other DBPs including haloacetonitriles (HANs), haloketones (HKs), chloropicrin and cyanogen halides (CNX) (Zhang et al., 2000; Krasner et al., 1989, 2006) and nitrosamines (Najm and Trussell, 2001; Mitch and Sedlak, 2002; Choi and Valentine, 2002a), some of which are more toxic than regulated DBPs (Muellner et al., 2007); (4) switching the secondary disinfectant from free chlorine to monochloramine increases more soluble lead released to the bulk water.

In addition, during the substitution reactions of chlorine with ammonium, the breakpoint phenomenon occurs. Figure 2.1-1 shows the typical breakpoint curve at pH 8 (Montgomery, 2005). It can be found that total chlorine is primarily present in the form of NH2Cl as the chlorine to ammonia molar ratio increases from 0 to 1. As the molar ratio of chlorine to ammonium increases from 1 to approximately 1.5, NH2Cl disproportionates to NHCl2, and total chlorine residual decreases with the formation of

+ - nitrogen gas and chloride (2NH3+3HOCl→N2+3H +3Cl +3H2O). At the molar ratio of 1.5 (the breakpoint), there is little or no total chlorine to be detected. Following further addition of chlorine after reaching the breakpoint, the total chlorine residual will linearly increase and free chlorine becomes the dominant chlorine species in the residual.

Reaction with readily 2+ oxidized species, e.g. Fe Destruction of Formation NH2Cl, Free of mostly formation & residual NH2Cl destruction chlorine of NHCl2 Total (small amount) Residual Chlorine Concentration pH 8

Breakpoint

0.5 1 1.5 2 Approx. Molar Ratio of Chlorine to Ammonia

Figure 2.1-1 Typical breakpoint curve for the chlorination of ammonia at pH 8

The breakpoint process can be complicated by the presence of certain organic amino compounds since they will provide an additional source of chlorine demand by reacting with the added chlorine to form relatively stable organic chloramines that cannot be completely oxidized. Figure 2.1-2 is the breakpoint curve when organic nitrogen compounds are present. Organic chloramine species form simultaneously with the inorganic chloramines, but they are generally more resistant to oxidation than inorganic chloramines. Therefore, the breakpoint appears to be not sharp as that observed for the

9 ammonia case shown in Figure 2.1-1, and incomplete oxidation of the organic chloramines formed results in measurable total chlorine residuals at the breakpoint. Furthermore, total chlorine residuals are composed of both free and combined chlorine fractions after the breakpoint.

Reaction with readily Formation of free residual chlorine oxidized species, e.g. Fe2+ and resistant organochloramines Formation of Destruction of NH Cl, NHCl and NH2Cl, NHCl2 2 2 and organic some chloramines organochloramines

Total Residual Free chlorine Chlorine Concentration Breakpoint Combined chlorine

0.5 1 1.5 2 Approx. Molar Ratio of Chlorine to Nitrogen

Figure 2.1-2 Typical breakpoint curve for the chlorination of ammonia and organic amines

2.2 Disinfection byproducts in drinking water

Drinking water disinfection protects consumers against the primary human health risk from pathogenic organisms. However, its processes cause unintended health hazard due to the formation of chemical disinfection byproducts (DBPs). DBPs are formed on the reaction of chlorine with naturally occurring organic matter (e.g. humic and fulvic acids) and inorganic ions (e.g. bromide) (Metcalf and Eddy, 2003).

Disinfection byproducts (DBPs), including organic chloramines, trihalomethanes (THMs), haloacetic acids (HAAs) and nitrosamines, have raised wide concerns in the past decades (Krasner et al., 1989; Zhang et al., 2000; Choi and Valentine, 2002). These DBPs have been found to be able to cause adverse reproductive and developmental effects in animals due to their carcinogenicity, mutagenicity and/or teratogenicity. Therefore, some of them have been strictly regulated (Letterman, 1999).

One of the biggest challenges is to understand and control their formation in drinking water treatment processes as well as in municipal water distribution systems (Letterman, 1999). Naturally occurring organic matter has been recognized as the principal precursor for the formation of DBPs. Factors affecting the formation of DBPs include reaction time, pH, temperature, disinfectant doses and application modes, bromide ion and precursor properties (Diehl et al., 2000; Hua and Reckhow, 2008).

2.2.1 Organic chloramines

During chlorination, nitrogenous organic (N-organic) compounds, such as amino acids, can react with chlorine to form organic chloramines either by the reaction of free chlorine (HOCl) with amino groups of organic molecules or by the transfer of reactive chlorine atoms from inorganic or organic chloramines to amino groups of organic molecules. Rates of N-organic compounds reacting with chlorine typically increase as the basicity (nucleophilicity) of the compounds increase (Jolley and Carpenter, 1983). In fresh surface waters, amino acids constitute a large portion of the dissolved organic nitrogen (Jersey and Johnson, 1992), and the predominant amino acids appear to be alanine, aspartic acid, glutamic acid, glycine and serine (Tuschall and Brezonik, 1980; Lytle and Perdue, 1981; Andrews, 1998). Proteins act as amino acid reservoirs in that they may undergo hydrolysis and release amino acids which can then react with added chlorine or chloramine. Similarly, some amino acids may be complexed with humic substances, and will also be released upon hydrolysis (Lytle and Perdue, 1981).

At very high chlorine doses, many other byproducts may be formed. For example, Croué et al. (1991) found that chlorination of tyrosine leads to the formation of MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone). Also, in their study of the chlorination of 22 amino acids, Hureiki et al. (1994) found that chlorination of amino acids led to the formation of halogenated compounds including trihalomethanes

(THMs), haloacids, halonitriles and haloketones (pH 8, 20C, 8 to 20 mole Cl2/mol amino acid, 72 hour contact time).

Some organic chloramines are relatively stable and some undergo rapid reaction (including oxidation and hydrolysis) to produce specific DBPs. For example, it has been reported that some organic chloramines decomposed to form dichloroacetonitrile (DCAN), which was reported to serve as an intermediate to yield dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), and chloroform (Peters et al., 1990). Some other N-organic compounds have been deemed as the precursors to form other DBPs including trihalomethanes (THMs), haloacids, halonitriles and haloketones (Hureiki et al. 1994).

The other concern that organic chloramines raise is that the formation of organic chloramines will contribute to the total chlorine measurements but they have very low disinfection capabilities, thus leading to an overestimation of the chlorine disinfectant in the treated water (Westerhoff and Mash, 2002).

2.2.2 Trihalomethanes (THMs) and haloacetic acids (HAAs)

THMs and HAAs are two typical classes of disinfection byproducts associated with chlorination. Chloroform and other THMs were first identified in chlorinated drinking water by Rook in 1974. Shortly afterward, the US Environmental Protection Agency (EPA) published the results of a national survey showing the ubiquitous presence of chloroform and other THMs in chlorinated drinking water (Richardson, 2003). In the same year, National Cancer Institute of US reported the linkage between chloroform and cancer in their laboratory animal tests (Richardson, 2003).

Many of mechanistic studies have been conducted by employing commercially available humic substances or well-defined model compound precursors, such as resorcinol for THMs and propanone for HAAs to describe chlorinated DBP formation. Haloform type reactions were shown to be the main formation pathway for the

12 formation of THMs (Boyce and Hornig, 1983). The haloform reaction is a substitution type reaction where hydrogen atoms on the carbon alpha to the carbonyl group of a methyl ketone or a compound that can be oxidized to a methyl ketone are replaced by halogens to form haloforms (Morris, 1976; Dickenson 2005).

Formation of HAAs in aqueous medium can be explained by Equations 2.2-1 to 2.2-4, in which propanone is used as the representative molecule for natural organic matter. (Xie, 2004):

Equation 2.2-1 CH 3COCCl3  nHOCl  CH (3-n)Cl n COCCl3 , where n 1,2 and 3

Equation 2.2-2 CH (3-n)Cl nCOCCl3  H2O  CH (3-n)Cl n COOH CHCl3

Equation 2.2-3 CH 3COR  HOCl  CCl 3COR, where R represents a methyl group

- Equation 2.2-4 CCl 3COR  H2O  CCl 3COOH R

At low pH, the reactions follow Equations 2.2-1 and 2.2-2, which is the oxidation of trichloropropanones producing tetra, penta and hexachloropropanones, followed by hydrolysis reaction of the chloropropanones to form mono-, di- and trichloroacetic acids (Xie, 2004). The other proposed pathway for the formation of HAAs follows Equations 2.2-3 and 2.2-4, which includes reactions between trichloroacetyl derivatives and chlorine followed by the hydrolysis reaction of the product (Xie, 2004; Reckhow et al., 1990).

The formation of THMs and HAAs and their speciation will be affected by water pH, chlorine dosage, water temperature, the nature and amount of NOM (in particular humic substances), concentration of bromide, and reaction time (Oxenford, 1996; Krasner, 1999; Rodriguez and Serodes, 2001). It has been found that TCAA formation did not change with pH in the range of 4-7, but decreased as pH was greater than 7 (Reckhow and Singer 1985; Summers et al., 1996; Chang, 2001). DCAA formation

13 was observed to be independent of pH possibly because it has a different formation mechanism from TCAA (Reckhow and Singer 1985; Reckhow et al., 1990; Liang and Singer, 2003). On the contrary, THM formation was increased with an increase in pH value. Increased chlorine concentration increased the formation of highly chlorinated species, such as TCAA and CHCl3, but had a less effect on DCAA formation (Reckhow and Singer, 1984 and 1985). Increased temperature led to more chlorinated-DBP formation compared with brominated-DBP for a reaction time of 24 hours, and it was attributed to the fact that chlorinated-DBPs had slower formation kinetics (Summers et al., 1996).

In natural water, precursors of THMs and HAAs are primarily natural organic matter, including humic and fulvic substances (Rook, 1977; Rook, 1976; Oliver 1978; Trussell and Umphres, 1978; Miller and Uden, 1983; Christman et al., 1983; Reckhow and Singer, 1984). These studies have found that humic acids are more reactive than fulvic acids in the formations of THMs. They have also found that the hydrophobic fraction in Suwannee River NOM had the highest potential of THM formation followed by the transphilic fraction and then by the hydrophilic fraction, whereas the higher TCAA formation was observed for the hydrophobic and transphilic fractions compared with hydrophilic fraction. No significant differences in DCAA formation were observed among the three fractions (Dickenson, 2005). Research has found effects of conventional treatment processes on the formation of HAAs and THMs. When humic NOM is preferentially removed by coagulation, flocculation and filtration, the relative proportion of non-humic NOM increased in the treated water. As a result, the molar ratio of HAA9 to TTHM and the molar ratio of dichloroacetic acid (DXAA) to trichloroacetic acid (TXAA) increased in the treated water compared with raw water, suggesting that HAA precursors are less readily removed, especially the DXAA, by conventional treatment (Hwang et al. 2001)

Natural organic matter and bromide ion are recognized as the main precursors for the formation of HAAs in drinking water systems (Liu et al., 2004; Xie, 2004; Qi et al.,

2004). Bromide ion is prevalent in some drinking water and wastewater. Chlorination of bromide containing waters will modify the chlorination process. Bromide is readily oxidized by hypochlorous acid (HOCl) to hypobromous acid (HOBr), which can participate in reactions similar to the free chlorine reactions. Compared to HOCl, HOBr is a more efficient halogen substitution agent (Rook et al., 1978; Westerhoff et al., 2004), and its reaction with NOM will significantly affect the formation and distribution of DBP (Wong and Davidson, 1977; Rook et al., 1978). Increasing bromide concentration, at a given chlorine dose, generally leads to increased formation of the total and the bromine-substituted THMs and HAAs (Minear and Bird, 1980; Krasner et al., 1989). In the case of THMs, it has been observed that the presence of bromide caused a decreased chloroform formation but an increased bromoform formation, and bromodichloromethane and dibromochloromethane concentrations passed through a maximum formation as bromide:TOC ratios increased (Minear and Bird, 1980; Summers et al., 1993; Westerhoff et al 2004). Cowman and Singer (1996) also reported that HAA9 speciation (except monochloro- and monobromo- acetic acids) at a high bromide concentration of more than 20 μM were formed following the order of tribromo- >dibromo> chlorodibromo- > bromodichloro- > bromochloro- >dichloro- and trichloro-acetic acid, which is opposite to the sequence of HAA9 speciation when bromide concentration is low (<3 μM).

2.2.3 Nitrosamines

NDMA has been detected in rubber, leather, metal, chemical and mining industries, around factories producing secondary amines or the rocket fuel 1,1-dimethylhydrazine (UDMH). It is also found in many food and beverage products (Mezyk et al., 2006). Rrecently, the occurrence of NDMA has also been related to water treatment practices, especially as a result of chloramination. Najm and Trussell (2001) reported the formation of more than 16 ng/L of NDMA in one chloraminated drinking water and approximately 400 ng/L in a filtered and chlorinated tertiary wastewater (AWWARF, 2005). The detection of NDMA has generated great interest and much research has

15 been conducted on NDMA formation mechanisms, factors influencing NDMA formation, and technologies to minimize NDMA formed in the effluent of treatment processes and distribution systems. Mechanistic studies of NDMA formation have become more available with the widespread availability of sensitive analytical techniques (Cheng et al., 2006; Mitch et al., 2003a). Several reaction pathways have been provided based on laboratory studies in model systems where reaction conditions could be controlled to allow a mechanistic interpretation of the results. The typical mechanisms that have been proposed and are well accepted include the reaction of monochloramine with organic nitrogen-containing precursors, such as dimethylamine (DMA), and the enhanced nitrosation of organic nitrogen-containing precursors by nitrite in the presence of HOCl (Chen and Valentine, 2006; Choi and Valentine, 2002b; Mitch et al., 2005; Mitch et al., 2003b).

Besides DMA, other organic nitrogen-containing precursors of NDMA include tertiary amines with dimethylamine functional groups, such as tetramethylthiuram (thiram, TMT), and strong-base anion exchange resin and cationic polyelectrolytes (Epi-DMA and polyDADMAC products) used as flocculation aids (Graham et al., 1995, Najm and Trussell, 2001; Westerhoff and Mash, 2002; Gerecke and Sedlak, 2003). The humic-type natural organic matter (NOM), which is ubiquitous in the surface water, has also been investigated as a significant NDMA precursor (Gerecke and Sedlak, 2003; Chen and Valentine, 2006; Gerecke and Sedlak, 2003). Different factions of NOM may have different contributions to NDMA formation. For example, hydrophilic fractions tended to form more NDMA than hydrophobic fractions and basic fractions appeared to have a larger NDMA formation potential than acid fractions.

Bromide plays a significant role on NDMA formation as well. A study with respect to the effect of bromide on NDMA formation through the mechanism of nitrosation of DMA by nitrite in the presence and the absence of HOCl was conducted (AWWARF, 2005). With 0.1 mM HOCl, the amount of NDMA formed increased from 5μg/L to 21μg/L as the bromide concentration increased from 0 mM to 1 mM. However, in the

16 absence of HOCl, NDMA formation was not promoted. It indicates that bromide catalyzes NDMA via a HOCl-nitrite interaction whereas classical nitrosation leads to insignificant NDMA formation.

2.3 Regulatory standards for drinking water

Trihalomethanes (THMs) and haloacetic acids (HAAs) are considered to be hazardous to humans at high concentrations and prolonged exposure (Freese and Nozaic, 2004). They have been found to be able to cause adverse reproductive and developmental effects in animals due to their carcinogenicity, mutagenicity and/or teratogenicity (Bull et al., 2001). Maximum contaminant levels (MCLs) for THMs and HAAs have been established in several industrialized countries (Serodes et al., 2003). The United States Environmental Protection Agency (EPA) and World Health Organization (WHO), regulate both THMs and HAAs. The stage 2 disinfectant/Disinfection Byproducts Rule sets the US maximum contaminant level for four THMs (chloroform, bromodichloromethane, dibromochloromethane and bromoform) and five HAAs (monochloro-, monobromo-, dichloro-, dibromo-, and trichloroacetic acid) at 80 ug/L and 60 ug/L, respectively, on the basis of a locational running annual average (EPA, 2006). Three bromochloro- species (bromochloroacetic acid, bromodichloroacetic acid and chlorodibromochloroacetic) are not included in either the Stage 1 or the Stage 2 D/DBPR. Guidelines for Canadian Drinking Water Quality established the Maximum

Acceptable Concentration (MAC) for HAA5 in drinking water at 80 μg/L based on a locational running annual average of a minimum of quarterly samples taken in the distribution system (Health Canada, 2008). The maximum acceptable concentration (MAC) for trihalomethanes (THMs) in drinking water is 100 ug/L based on a locational running annual average of a minimum of quarterly samples taken at the point in the distribution system with the highest potential THM levels (Health Canada, 2006). The Ontario Ministry of the Environment has a maximum allowable concentration of 100 ng/L for THMs expressed as a running annual average (OMOE, 2008). The WHO has been more specific by setting MCLs for DCAA (50 μg/L) and TCAA (100 μg/L) in

17 drinking water. Only THMs are covered by legislation (MCL of 150 μg/L for total THMs) in Europe (Barron et al., 2004). In UK, the regulations allow THMs up to a concentration of 100 μg/L.

Currently, there are no federal drinking water guidelines for nitrosamines in Canada or the United States. The U.S. Environmental Protection Agency (EPA) has added NDMA, NPYR, N-nitrosodiethylamine (NDEA), N-nitroso-n-methylethylamine (NMEA), N-nitrosodi-n-propylamine (NDPA), and N-nitrosodi-n-butylamine (NDBA) to the Unregulated Contaminant Monitoring Rule 2 (UCMR-2) (Chen and Valentine, 2006), and NDMA, NDEA, NDPA, NPYR and NDPhA to the third version of the Contaminant Candidate List (CCL3) (Charrois and Hrudey, 2007). The Ontario Ministry of the Environment has a maximum allowable concentration of 9 ng/L for NDMA (OMOE, 2008), whereas the California Department of Public Health has established a notification level of 10 ng/L for NDMA, NDEA, and NDPA, and a Public Health Goal (PHG) of 3 ng/L for NDMA (CDPH, 2009).

2.4 Swimming pools

Swimming is one of the most popular activities nowadays due to its feasibility for people of all ages and physical abilities. Swimming not only provides leisure but also provides health benefits (Zwiener et al., 2006). Hundreds of thousands of bathers visit public pools every year. In the US, more than 368 million people visit about 250,000 public swimming pools each year. In Germany, close to 300 million people visit pools each year. In the UK, approximately 36% of adults (>15 years of age) visit swimming pools at least once a week.

Swimming pool includes private pools, public pools, competition pools, exercise pools, hot tubs and spa pools. Public pools are designed for the general public and private pools are built exclusively for a few people or in a home. Public swimming pools can locate on campus or in a community center where swimming pools include indoor swimming pools and outdoor swimming pools. In comparison with private pools,

18 public pools encounter larger amount and more diverse users, which means a greater responsibility to meet standards for treatment techniques and water quality. Hot tubs and spas are pools with high water temperature and used for relaxation or therapy indoor or outdoor.

Swimming pools have different dimensions. In the US, swimming pools are either 25 yards (25 meters) or 50 meters. Most pools are between 10 m and 50 m wide. The depth of a swimming pool depends on the purpose of the pool and whether it is open to the public. It ranges from 1 to 2 meters for private pools and 3 to 5.5 meters for public pools.

Normally, swimming pool water is recirculated and purified using simple processes including sand filtration and/or flocculation, while flocculation is not generally used for the treatment of swimming pool water in North America. Compared with drinking water, swimming pool water normally is under continuous loading of organic carbon and nitrogen and microorganisms from swimmers. Therefore, it is important to have continuous and effective disinfection to prevent waterborne disease spreading among swimmers. However, disinfectants, normally free chlorine, react with the large number of organic compounds from swimmers, and thus produce a high concentration of disinfection byproducts (DBPs) in swimming pool water (Beech et al., 1980).

2.5 Disinfection of swimming pools

Disinfection is mandatory for swimming pool water since it is continuously contaminated by swimmers and the water is recirculated with a long replacement time. The World Health Organization (WHO, 2006) has identified some of the potential hazards associated with recreational water use, which include infections caused by feces-associated microbes (such as viruses and bacteria) as well as protozoa (such as Giardia and Cryptosporidium) which are resistant to chlorine. The United States Environmental Protection Agency therefore issued recreational water standards in 2003 to restrain the bacterial problem. Similarly, the International Organization for

Standardization recently published the standards (ISO 15553) which are applicable for the examination of surface and ground waters, treated waters, mineral waters, swimming pool and recreational waters(Zwiener et al., 2006).

Disinfection is important for preventing the spread of diseases and pathogens between swimmers. Normally, public swimming pools are disinfected by gaseous chlorine or sodium hypochlorite and cartridge filters whereas private pools typically use stabilized chlorine. Both gaseous chlorine and sodium hypochlorite disinfect water in the form of hypochlorous acid (HOCl), which is formed by hydrolysis reactions as shown in Equations 2.5-1 and 2.5-2 and can act as a general biocide killing germs, micro-organisms and algae (Zwiener et al., 2006; White, 1999). A concentration of 1 mg/L to 3 mg/L of free chlorine is recommended for swimming pool disinfection in the United States, the UK, and Australia (EPA, 1979). In Canada, OMHLC requires a residual of free available chlorine or total bromine of at least 5 mg/L but not more than 10 mg/L in spa water (OMHLC, 2006) and Region of Waterloo has a recommended concentration of free chlorine in public swimming pool of 1.5 to 3.0 mg/L (Region of Waterloo Public Health, 1999). In Germany, lower concentration of 0.3-0.6 mg/L free chlorine is recommended since coagulation/flocculation is widely applied for swimming pool water treatment (Zwiener et al., 2006).

+ − Equation 2.5-1 Clퟐ + HퟐO ⇌ HOCl + H + Cl

− Equation 2.5-2 OCl + H+ ⇌ HOCl

Stabilized chlorine, typically trichloro-S-triazinetrione (Trichloroisocyanuric acid) in the form of stick or tablet, is often used for disinfection of private swimming pools. Stabilized chlorine has the same active disinfectant (HOCl) as gaseous chlorine and sodium hypochlorite. When stabilized chlorine is added into pool water, the chlorine atoms hydrolyze from the rest of the molecule, as shown in Equation 2.5-3, forming hypochlorous acid (HOCl) (Muellner et al., 2007; Zwiener et al., 2006).

Equation 2.5-3 CퟑClퟑNퟑOퟑ + ퟑHퟐO ⇌ CퟑNퟑOퟑHퟑ + ퟑHOCl

C3Cl3N3O3 Stabilizer (cyanuric acid) is also widely used for outdoor swimming pools to prevent free chlorine photolysis under direct sun irradiation. Photolysis of HOCl primarily produces hydroxyl radicals (∙OH) and chlorine radicals (∙Cl) (Nowell and Hoigne, 1992). Consequently, chain reactions with organic matter will decompose HOCl in the aqueous as listed in Equations 5.1-1 to 5.1-4 (Oliver and Carey, 1977; Feng et al., 2007).

Equation 2.5-4  OH  RH   R  H2O

Equation 2.5-5  R  HOCl  RCl   OH

Equation 2.5-6  Cl  RH   R  HCl

Equation 2.5-7  R  HOCl  ROH   Cl

In addition, chlorine is more than three times as effective as bromine against Escherichia coli, and is more than six times more effective than iodine in swimming pool water disinfection (Koski et al., 1966). However, in order to improve the life of the free-halogen antimicrobial, bromine could be used for disinfection of swimming pools, especially spas (hot tubs), where the high water temperature may destabilize chlorine and other buffering compounds in the water.

Although chlorine-based disinfection is still the most common technique for swimming pool disinfection in North America, increased awareness of its formation of disinfection byproducts (DBPs) has raised more and more concerns regarding the safety of swimming pool water. Swimming pools should minimize the DBP formation while maintain sufficient disinfection to conserve the positive aspects of swimming and prevent illnesses associated with swimming (Lee et al., 2009). In order to avoid or minimized the DBP formation from chlorine-based disinfection, healthier and more effective alternatives to chlorine have been sought. Therefore, along with chlorine technique, a variety of disinfection technologies are currently available in the market, which include ozone (Richardson et al., 1999), ultraviolet (UV) radiation (Craik et al.,

2001), and electrochemically generated mixed oxidants (EGMOs) (Patermarakis and Fountoukidis, 1990).

Ozone is becoming more popular in swimming pool water treatment since it has high chemical oxidation potential and is highly effective in disinfection. Ozone does not produce halogenated DBPs, such as THMs. It also reduces the chlorine usage by oxidizing organic matter in swimming pool water. However, relatively high doses of ozone are required in swimming pool water disinfection and it produces no disinfectant residual in the water. Therefore, ozone disinfection is usually followed by sequential disinfection with chlorine (ozone/chlorine) (Venczel et al., 1997; Kleiser and Frimmel, 2000; Jo et al., 2005).

Ultraviolet (UV) radiation assists swimming pool disinfection by providing a protection against potentially harmful organisms, such as feces-associated microbes, (viruses and bacteria) and protozoa (Giardia and Cryptosporidium). UV radiation inactivates harmful organisms by disrupting the genetic material within the cell. It neither affects the balance of the pool water nor reduces the amount of chloramines within the water. However, it improves the pool water quality and allows the residual chlorine to work more effectively at even lower concentrations (Cassan et al., 2006). Traditionally, UV radiation is used to inactivate microorganisms by destroying the genetic information in DNA. The germicidal wavelength is 253.7 nm (Morgan, 1989). Low-pressure and medium-pressure UV lamps can both be used for swimming pool disinfection. The low-pressure lamps emit a maximum energy output at a wave length of 254 nm and the medium-pressure lamps emit energy at wavelengths from 200 to 600 nm. Given there is no disinfectant residual from UV radiation, it also needs to be combined with a traditional disinfectant to maintain a minimum residual (Cassan et al., 2006).

Other disinfection technologies include electrochemically generated mixed oxidants EGMOs, electronic oxidation/oxygen, and the use of PHMB (polyhexamethylene biguanid). In a EGMOs system, electric current is passed through a salt brine solution

22 where free chlorine in a form of HOCl is the primary oxidant being produced although other oxidants (O3, chlorine dioxide, H2O2, and some short-lived species) have also been argued to be produced by the system (USACHPPM, 2006; Patermarakis and Fountoukidis, 1990; Venczel et al., 1997; Kerwick et al., 2005). In an electronic oxidation system, species with high oxidation-reduction potential (hydroxyl, atomic oxygen, and hydrogen peroxide) as well as molecular oxygen can be produced from water molecules themselves. These high energy species will not only disinfect the water but also oxidize organic contaminants in the water. The residual molecular oxygen then combines with copper ion to provide effective disinfection. PHMB (polyhexamethylene biguanid) has also been used for swimming pool disinfection. It is generally less harsh and more stable in the pool water, but it is also more expensive and requires periodic shock treatment of the pool to maintain its efficacy (Dawson et al., 1983; Goeres et al., 2004).

2.6 Disinfection byproducts in swimming pools

Compared with drinking water, swimming pool water has more sources of organic compounds that can react with disinfectant to form disinfection byproducts (DBPs). Swimmers introduce body fluids (perspiration, urine, mucus, skin particles, hair, etc.), skin particles, hair, microorganisms, cosmetics, and other personal care products (PCPs) such as chemicals used in sunscreens into swimming pool water. In addition, organic matter comes from the environment such as leaves from surrounding trees for outdoor pools, algae and other biota. Moreover, source water for swimming pool also introduces natural organic matter into swimming pool water (Zwiener et al., 2006; Lee et al., 2009).

Organic compounds introduced into and accumulated in swimming pool water react with disinfectant, normally free chlorine, to form a wide range of DBPs (Lee et al., 2009; Beech et al., 1980). For example, body fluid and several active ingredients of sunscreens and their halogenated reaction products have been identified in swimming

23 pool water by Zwiener et al. (2006). A wide range of DBPs in swimming pool water include combined chlorine, trihalomethanes (THMs) (Richardson, 2003), haloacetic acids (HAAs), haloacetonitriles (Nieuwenhuihsen et al., 2000; Gunten et al., 2001), haloketones (Xu et al., 2002) and nitrosamines (Walse and Mitch, 2008).

Among these DBPs combined chlorine is routinely monitored as measurements of monochloramine (NH2Cl), dichloramine (NHCl2) and trichloramine (NCl3) by swimming pools. It has been found that combined chlorine, especially trichloramine which is highly volatile and irritating, is susceptible to induce respiratory, ocular and skin irritations in lifeguards and swimmers and recently has raised concerns of their possible roles in asthma (Jacobs et al., 2007; Massin et al., 1998; King et al., 2006; Bernard et al., 2005).

Even though DBPs are not routinely monitored by swimming pools, research has shown that they are widely present in swimming pool water. Trihalomethanes (THMs) such as chloroform, bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform are the most intensively studied DBPs. They have been found present at much higher concentration in chlorinated swimming pool water than in drinking water (Chu and Nieuwenhuijsen, 2002; Erdinger et al., 2004). Since the first report in swimming pool water in 1980 by Beech et al. (1980), THMs have been widely measured in swimming pool water around the world (Aggazzotti and Predieri, 1986; Aggazzotti et al., 1990; Chu and Nieuwenhuijsen, 2002).

THMs, especially chloroform, can be found in the air space above the water due to their high volatility, which makes inhalation the most import route of its exposure for swimmers and none swimmers (such as lifeguards) working around swimming pools. Although inhalation is a less important route of THM exposure in outdoor swimming pools (Aggazzotti et al., 1993; Thickett et al., 2002), THMs can be dermally ingested by permeating the skin due to its nonpolarity (Xu et al., 2002). In addition, accidentally swallowing pool water could also be possible route of exposure, especially for younger swimmers, therefore making it a significant concern for parents

(Fantuzzi et al., 2001; Chu and Nieuwenhuijsen, 2002; Erdinger et al., 2004).

Research has shown that THMs concentration in swimming pool water is correlated with TOC values. In swimming pool water, high TOC values generally correspond to high formation of THMs due to the readily occurred reactions between high concentration of organic matter and chlorine (Chu and Nieuwenhuijsen, 2002; Kim et al., 2002). THM formation in swimming pool has also been found to be correlated to pH values of pool water. High pH values lead to high THM formation since hydroxyl groups at high pH promote the hydrolysis reactions of carbon chain molecule making THM formation at a higher yield in swimming pool water (Garcia-Villanova et al., 1997; Thacker and Nitnaware, 2003; AWWA, 1999). However, low pH value (lower than 7.4) is not recommended considering skin irritation and metal/equipment corrosion in swimming pool system (Missouri department of health and senior service section for environmental public health). Besides, low pH value can cause significant increase of HAA formation even though it reduces THM formation (Singer, 1994).

Along with the wide recognition of THM formation in swimming pool water, other DBPs, such as haloacetic acids (HAAs) (Judd and Black, 2000; Li and Blatchley, 2007; Zwiener et al., 2006) and nitrosamines (Walse and Mitch, 2008) have also been reported in swimming pools. Due to their carcinogenic potency, they are raising more and more concerns (Nieuwenhuihsen et al., 2000; EPA). Compared with THMs, HAAs and nitrosamines have different properties. HAAs are more polar and not volatile. They do not readily permeate the skin and be absorbed by swimmer (Xu et al., 2002). The only route of exposure for HAAs is by accidental swallowing, and thus they have a much lower uptake than THMs (Zwiener et al., 2006). Walse et al. (2008) reported that nitrosmaines, mainly NDMA, are at levels up to 500-fold greater in swimming pool water than that in drinking water of 0.7 ng/L (Mitch et al., 2003b). Routes of exposure for nitrosamines include ingestion and inhalation since they are semivolatile.

In addition to chlorinated DBPs, brominated and iodinated compounds are also of toxicological concern in swimming pools (Zwiener et al., 2006). Haloketones are

25 another class of emerging DBPs of concern in swimming pool water, which can both permeate the skin (Xu et al., 2002) and irritate the eyes, skin, and mucous membranes (Chiswell and Wildsoet, 1989).

2.7 Regulations and methods to minimize DBP formation in swimming pool water

Unlike in drinking water scenario where THMs and HAAs are regulated chlorine disinfection byproducts (Krasner et al., 1989), there are no regulations specifying total allowance of THMs or HAAs in swimming pool water except various guidelines issued for their control (WHO, 2000). Given that THMs (such as chloroform, bromodichloromethane, chlorodibromomethane and bromoform) are not routinely measured by swimming pools, limited literature shows that concentration of chloroform ranged from 14 to 198 µg/L and the other THMs were at lower values in swimming pools (Aggazzotti et al., 1993; Aggazzotti et al., 1990; Cammann and Hubner, 1995; Lahl et al., 1981). Literature also shows that speciation of THMs depends on the disinfectant type. Chloroform is the major species when hypochlorous acid (HOCl) is used for swimming pool disinfection (Judd and Jeffrey, 1995).

Even though there are no regulatory standards regarding DBP formation and concentrations in swimming pool water, DBP formation should be minimized to reduce their potential adverse health risk and thus the positive health effects from swimming can be maximized (Zwiener et al., 2006). Factors influencing DBP formation in swimming pool water include the number of swimmers in the pool, chlorine dosage, bromide concentration, extent of ventilation for volatile DBPs and feed water quality (normally tap water) (Heller-Grossman et al., 1993; Lahl et al., 1981). Therefore, DBP formation can be reduced by assuring the cleanliness of swimmers, lowering dose of disinfectant while increasing circulation and maintaining its effectiveness, in indoor pools (Zwiener et al., 2006). On the other hand, new treatment processes, such as ozone oxidation and electrochemically generated mixed oxidant

(EGMOs), can reduce the DBP formation in swimming pool water by decreasing organic matters (Patermarakis and Fountoukidis, 1990; Richardson et al., 1999).

2.8 Possible DBP precursors in swimming pool water

Disinfection is mandatory for swimming pool water to protect swimmers from infection and to prevent waterborne disease spreading among swimmers. Free chlorine is widely used for swimming pool disinfection. On the other hand, microorganisms and organic substance are continuously introduced into swimming pool water by swimmers. Consequently, organic substance can accumulate in swimming pool water due to inefficient removal by treatment processes and the long replacement time of swimming pool water.

Accumulated organic matters react with chlorine forms a variety of disinfection byproducts (DBPs) in swimming pool water. As mentioned in Section 2.7, formation of DBPs in swimming pool is strongly influenced by operating conditions (water parameters and influence from swimmers) and treatment processes. Besides the influence from treatment processes, it is of obvious interest to investigate operating conditions with specific regard to DBP formation on a simulated swimming pool water matrix.

2.8.1 Body fluid analogues (BFAs) in simulated swimming pools

Judd et al. (2000) (2003) have reported results for both a bench-scale pool and a pilot-scale pool using body fluid analogues (BFAs) including key dissolved organic and inorganic components of human perspiration and urine, to represent endogenous species in urine and sweat. In addition, humic acid (HA), which is known to have a greater THM formation propensity than fulvic acids (Reckhow et al., 1990), was added to replicate soiling from swimmer. Dosing of BFAs and humic acid replicates the bather load in their simulated swimming pools. Results confirmed the capability of representing by showing that DBP formation (THMs and combined chlorine) is

27 sensitive to the bromide concentration, to pH value (between ranges of 7.2and 7.8), to intermittent dosing (occasional bather increase). Molecular structures of BFA components are shown in Table 2.8-1.

Table 2.8-1 Molecular structure of BFA components

BFA component Molecular Structure

Ammonium chloride (53.491 g/mol) NH4Cl

Urea (60.06 g/mol)

Histidine (155.15 g/mol)

Hippuric acid (179.17 g/mol)

Uric acid (168 g/mol)

Citric acid (192.124 g/mol)

Creatinine (113.118 g/mol)

2.8.2 Personal care products (PCPs) in simulated swimming pools

Swimmers introduce body fluids (perspiration, urine, mucus, skin particles, hair, etc.), skin particles, hair, microorganisms, cosmetics, and other personal-care products (PCPs) such as chemicals used in sunscreens into swimming pool water (Zwiener et al., 2006; Lee et al., 2009). Research has also identified several active ingredients of sunscreens and their halogenated products in swimming pool water (Zwiener et al. 2006).

Table 2.8-2 Molecular structure of PCP additives

Name Molecular Structure Diethanolamine (DELA) (105.14 g/mol)

Padimate O (NPABAO) (277.402 g/mol)

Triethanolamine (149.188 g/mol)

Nitrilotriacetic acid (191.14 g/mol)

Tetramethylammonium Chloride (109.60 g/mol)

Tetrabutylammonium Chloride (277.914)

Cetyltrimethylammonium Chloride (320.00 g/mol)

Choline chloride (139.62 g/mol)

cocamidopropyl betaine (342.52 g/mol) behentrimonium chloride (BTAC-228) (404.16 g/mol)

Molecular structures of 10PCP additives that might be expected to wash off bathers are shown in Table 2.8-2 above. They were selected to represent possible active components in personal care products such as shampoo, body lotion, cosmetics, and sunscreens. These PCP compounds include secondary amine, tertiary amine and quaternary amines considering they might have high potential to form nitrosamines.

2.9 Summary of research gaps

As in drinking water, a variety of disinfection byproducts can be formed in swimming pool water due to the reaction between organic input from swimmers and relatively high concentration of disinfectant. However, most research has been focusing on THM formation in swimming pool water. Limited information on wide range of DBPs and their precursors, especially precursors associated with the bathers, such as Body Fluid Analogues (BFAs) and Personal Care Products (PCPs). In addition, limited research examined the differences between indoor swimming pools and outdoor swimming pools.

In order to reduce the knowledge gap concerning DBP formation and DBP precursors in swimming pool water as well as to find clues applicable to drinking water treatment, this study uses swimming pool water as background water matrix to identify potential DBP precursors from BFAs and PCP additives. A wide range of swimming pools are selected and measured for DBP formation examination. BFAs and PCP additives are investigated regarding their DBP formation potential in both simulated swimming pool water and in real swimming pool water.

Chapter 3 Materials and methods

Materials and methods

This chapter gives details of materials and methods employed in this research. Materials include chemicals reagents and standard materials along with glassware used in this research. Methods include sampling methods, experimental methods, and analytical methods along with quality control measurements during this research.

3.1 Materials

Content for materials includes their name, grade, supplier information and other information.

3.1.1 Chemical reagents and Standard materials

Chemical reagents are grouped into normal chemicals, body fluid analogues (BFAs), personal care products (PCPs), swimming pool stabilizer, and humic acid along with standard materials.

3.1.1.1 Routine chemicals

Chemical reagents used in this research are mainly supplied by Sigma-Aldrich (Oakville, ON) and VWR (Mississauga, ON).

Chemicals used for chlorination and chloramination during swimming pool simulation bench-scale experiment were sodium hypochlorite 6% (NaOCl) and ammonium chloride (NH4Cl) (ACS grade). They were both obtained from VWR (Mississauga,

ON). Monochloramine (NH2Cl) was produced on site. Chlorine residual was quenched with ascorbic acid (ACS grade) from JT baker (Phillipsburg, NJ, USA)

Buffer solutions used in this research include phosphate buffer of pH 6.9 and borate buffer of pH 8.0. Phosphate buffer was used as HPLC eluent for organic chloramine measurement and borate buffer was used for sample pH adjustment. Potassium phosphate (monobasic and dibasic) for phosphate buffer was supplied by Sigma-Aldrich (Oakville, ON). Boric acid (ACS grade) for borate buffer was obtained from VWR (Mississauga, ON).

Chemicals used for the analysis of organic chloramines include sodium acetate (anhydrous ≥ 99.0 %) from Sigma-Aldrich (Oakville, ON), as well as glycine, and potassium iodide (ACS grade) from JT baker (Phillipsburg, NJ, USA).

Solvents included methanol (chromasolv gradient grade HPLC <99.9%), dichloromethane (capillary GC grade, ≥99.9%) obtained from VWR (Mississauga, ON), methyl-tert-butyl-ether (MtBE) VWR (Mississauga, ON).and Milli-Q® water (Millipore, Mississauga, ON).

3.1.1.2 BFAs

Body fluid analogue (BFA) chemicals include seven chemicals. They were all supplied by Sigma-Aldrich (Oakville, ON). Their name and grade are shown in Table 3.1-1.

Table 3.1-1 Grade of BFAs Name Grade Ammonium chloride ACS grade Urea meets USP testing specifications Histidine Reagent Plus®, ≥99% (TLC) Hippuric acid 98% Uric acid ≥99%, crystalline Citric acid ACS reagent, ≥99.5% Creatinine anhydrous

Stock solution concentrations of BFA components are shown in Table 3.1-2. Stock solutions are dosed at a dilution factor of 1000 to simulate swimming pool water.

Table 3.1-2 Stock solution concentrations of BFA compounds (Judd et al., 2003) Ingredient mg/L Ammonium chloride 2000 Urea 14800 Histidine 1210 Hippuric acid 1710 Uric acid 490 Citric acid 640 Sodium phosphate 4300 Creatinine 1800

3.1.1.3 PCP compounds

Personal care products (PCPs) used in this research covered a wide range of additives used in shampoo and hair conditioner, body lotion, cosmetics and sunscreens. The detailed information about grade and supplier is shown in Table 3.1-3. The concentration of PCP compounds used for simulated swimming pool water was 1 mg/L.

Table 3.1-3 Information of PCP additives Name Grade Supplier Diethanolamine (DELA) ≥99.5% (GC) Padimate O (NPABAO) 98% Nitrilotriacetic acid ≥99% (Fluka) Triethanolamine ≥99.0% (GC) Tetramethylammonium Sigma-Aldrich ≥99.0% (AT) (Fluka) chloride (Oakville, ON) Tetrabutylammonium ≥99.0% (AT) chloride (Fluka) Cetyltrimethylammonium 25 wt. % in H O chloride 2 Choline chloride 99% VWR (Mississauga, ON) 30-35 wt. % in Spectrum chemicals and Cocamidopropyl betaine A.C.S water laboratory products +NaCl Behentrimonium chloride 79-81 wt. % Advanced Tech&Ind (BTAC-228) in tablet CO.,LTD.

3.1.1.4 Pool stabilizer (cyanuric acid) and humic acid

Stabilizer used in this research was cyanuric acid 99% from VWR (Mississauga, ON). Humic acid was obtained from Sigma-Aldrich (Oakville, ON), which is soil base extract.

3.1.1.5 Chemical standards

Standard material used for nitrosamine calibration include N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosodibutylamine (NDBA), and deuterated N-nitrosodimethylamine-d6 (NDMA-d6). They were obtained from Sigma-Aldrich (Oakville, ON). Other nitrosamine standards, such as N-nitrosomethylethylamine (NMEA), N-nitrosomorpholine (NMOR), and N-nitrosodipropylamine (NDPA) were obtained as solution of 100 μg/L in methanol from Ultra Scientific (N. Kingstown, RI, USA).

Chloro-glycine was used as standard material for organic chloramines. It was made by the reaction of sodium hypochlorite 6% (NaOCl) from VWR (Mississauga, ON) and glycine from JT baker (Phillipsburg, NJ, USA) in site of the lab.

Standards for THMs and HAAs were EPA 501 THM mixture 200 μg/ml in methanol from VWR (Mississauga, ON) and EPA 552.2 Haloacetic Acids mixture 2000 μg/mL (Supelco) in methyl tert-butyl ether from Sigma-Aldrich (Oakville, ON), respectively.

3.1.2 Glassware

Glassware employed in this study was cleaned using a Miele dishwasher then rinsed three times with deionized water followed by two rinses with Milli-Q® water and then dried in the oven at approximately 250 degrees Celsius for 4 hours.

34 3.2 Methods

3.2.1 Experimental methods

Free chlorine dosing solution was made by diluting 5 mL concentrated 10-12% sodium hypochlorite in a 250 mL volumetric flask with Milli-Q water and the concentration was between 2200 to 2400 mg/L Cl2. The solution was then stored at 4 °C degrees Celsius. Monochloramine dosing solution was prepared by adding the chlorine dosing solution to well-stirred ammonia chloride solution (50 mM) and stirring for at least 30 minutes. The volumes of ammonium chloride solution and the chlorine dosing solution were calculated based on Cl2/N molar ration of 0.8:1. The concentration of preformed chloramine dosing solution was between 1200 and 1600 mg/L.

Body Fluid Analogue (BFA) stock solutions were prepared at concentrations in Table 3.1-2 and kept at 4 degrees Celsius. Personal Care Product (PCP) stock solution were prepared at concentration of 1000 or 10000 mg/L depending on their solubility and kept at 4 degrees Celsius. The targeted dosages of BFAs were achieved by dosing 1 ml stock solution to the batch reactor of 1 liter amber bottles. The target dosages of PCP s were achieved by dosing 1 ml or 100 µL stock solutions to the batch reactor of 1 liter amber bottles depending on stock solution concentration of 1000 mg/L or 10000 mg/L, respectively.

Amber bottles of 1 liter were used as batch reactors for simulated and real swimming pool water experiments. For experiments with simulated swimming pool water, BFAs and/or PCPs were dosed before free chlorine or monochloramine were dosed. pH values were controlled at 7.5 by borate buffer of pH 8 or phosphate buffer of 7.6 and adjusted by hydrochloric acid. For experiments with real swimming pool water samples, free chlorine was dosed right before the dosing of BFAs and PCPs since swimming pool water already contains free chlorine. Samples were incubated for 24±1 hours at room temperature which is similar to a real pool water temperature. After the incubation period, free chlorine, total chlorine, pH, TOC were measured. Then,

35 reactions were stopped by quenching agent of Ascorbic acid before DBPs (THMs, HAAs, and nitrosamines) were sampled.

3.2.2 Analytical methods

3.2.2.1 Organic chloramine (HPLC)

Organic chloramines was measured using size exclusion chromatography (SEC) followed by reaction with iodide coupled with amperometric detection. Measurements were conducted on a two-pump liquid chromatography (LC) system which consisted of a Dionex DX 500 liquid chromatograph, a Macrosphere GPC analytical column (60 Å 7.5 x 300 mm) with a Macrosphere GPC guard column (300 Å 4.6 x 7.5 mm), a PC-10 pneumatic controller post column delivery system, a mixing tee connected to a 375 μL knitted flurorpolymer reacted coil, and an amperometric detector using a thin layer glassy carbon electrode and a Dionex ED 40 electrochemical detector. All components of the Dionex LC system were obtained from the Dionex Corporation (Sunnyvale, CA, USA).

Organic chloramine standard (chlorinated glycine, N-Cl-glycine) was prepared by reacting NaOCl and glycine at a molar ratio of 1:10 for 1 hour. Concentration of newly prepared N-Cl-glycine solution was verified by measuring the total chlorine and free chlorine with the HACH® kit. Standard solutions ranging from 0 to 2 mg/L were used for the calibration of SEC analysis every time before running samples. The samples and standards were analyzed immediately after preparation. The working potential of the electrode was -0.1V and the retention times of the organic chloramines were approximately 5.45 minutes, 5.85 minutes and 6.65 minutes corresponding to molecular size of large, medium, small, respectively. The operating conditions for organic chloramine are shown in Table 3.2-1.

Table 3.2-1 Organic chloramine analysis – HPLC operating conditions Parameter Description System Dionex DX 500 HPLC Analytical column Macrosphere GPC (60 Å 7.5 x 300 mm) Guard column Macrosphere GPC (300 Å 4.6 x 7.5 mm) Detector Dionex ED 40 electrochemical detector Column temperature 35°C Eluent solution pH 6.9 phosphate buffer Potassium iodide(0.09 M), Post column solution Sodium acetate (0.294 M) Glacial acetic acid (1.4%). Flow Rate 1.5 ml/min at 35°C PC-10 pressure 70 psi Injection volume 0.5 ml

3.2.2.2 THMs and HAAs (GC)

The analysis of THMs and HAAs is performed according to EPA Standard Method 6231 B and 6251 B, respectively (APHA-AWWA-WEF, 2005). The principle was based on liquid–liquid extraction of THM and HAA9 with methyl-tert-butyl-ether

(MtBE). For HAA9, diazomethane derivatization was also applied after extraction. The surrogate standards for THMs and HAA9 were 1, 2-dibromopropane and 2, 3, 5, 6-tetrafluorobenzoic acid, respectively. The gas chromatograph used for this analysis is a Hewlett Packard 5890 Series II Plus Gas Chromatograph (Mississauga, ON) using an electron capture detector (GC-ECD) and a DB 5.625 capillary column (30 m х 0.25 mm х 0.25 μm, Agilent Technologies Canada Inc., Mississauga, ON). The operating conditions for THMs and HAAs are shown in Tables 3.2-2 and 3.2-3, respectively.

Table 3.2-2 Trihalomethane analysis – Gas Chromatograph operating conditions Parameter Description System HP5890 Series II Plus Column DB 5.625 capillary column Injector Temperature 200°C Detector Temperature 300°C 40°C for 4.0 min Temperature Program 4°C/min temperature ramp to 95°C 60°C/min temperature ramp to 200°C Carrier Gas Helium Flow Rate 1.2 ml/min at 35°C Injection volume 1 µL

Table 3.2-3 HAA9 analysis– Gas Chromatograph operating conditions Parameter Description System HP5890 Series II Plus Column DB 5.625capillary column Injector Temperature 200°C Detector Temperature 300°C 35°C for 10 min 2.5°C/min temperature ramp to 65°C Temperature Program 10°C/min temperature ramp to 85°C 20°C/min temperature ramp to 205°C hold for 7 min Carrier Gas Helium 1.2 mL/min

Makeup gas: 5% CH4. 95% Ar 23.1mL/min Injection volume 1 µL

3.2.2.3 Nitrosamines (GC/MS)

Nitrosamines were determined by the procedures including solid phase extraction, dichloromethane (DCM) desorption followed by GC/MS analysis (Cheng et al., 2006;

Munch, 2004). N-nitrosodimethylamine-d6 (d6-NDMA) was used as a surrogate standard to correct for extraction efficiency.

The nitrosamine compounds were extracted from their aqueous solutions (500 mL) by adding approximately 200mg of Lewatit® activated carbon beads. The bottles were then capped using a Teflon-lined cap and shaken on a Big Bill Orbital shaker for 60

38 minutes at 250 rpm. After shaking, the contents of a sample bottle were filtered under vacuum filtration through Whatman Filter paper grade 4. The filter paper with the carbon beads was then transferred to an aluminum tray and allowed to dry for approximately 20 minutes. The carbon beads were then transferred to a 2.0 mL amber GC vial and 500 µL of DCM was added to desorb nitrosamines from the beads. Before analysis, the samples were stored in the dark at 4 °C. The DCM layer was then analyzed for nitrosamine by GC/MS.

The instrument used for nitrosamine analysis is a Varian 4000 GC coupled with VF-5 mass spectrometer and CP 8400 autosampler. A Varian 1079 injector with temperature programmed vaporization is applied. The programmed temperature vaporizer (PTV) liner packed with Carbofrit is ordered from Chromatographic Specialties (3.4 mm ID, 5.0 mm OD, 54 mm length). The GC column is DB1701 (30 m х 0.25 mm х 0.25 μm). Methanol is used as a chemical ionization (CI) reagent liquid. Injection volume was 8 μL. Instrument conditions for nitrosamines analysis are shown in Table 3.2-4. Nine nitrosamines and their corresponding retention time are listed in Table 3.2-5. The MDLs of the nitrosamines are determined by extracting eight replicate samples at 1 ng/L and analyzing by GC/MS for 9 nitrosamine compounds. The standard deviation of each compound was calculated and multiplied by a factor of 3.00 (t-value of 7 degrees for freedom and 99% confidence interval) to obtain the nitrosamines MDLs which are given in Table 3.2-6.

Table 3.2-4 Nitrosamine analysis-GC/MS operating condition Parameter Description Injection volume 8uL 35 ºC (0.8 min), Inlet temperature program 200 ºC/min to 240 ºC (24 min) Initial on (5); 0.8min off Inlet split ratio 6min on (100) 35ºC (4.5 min) Oven temperature program 15ºC/min to 200ºC 40ºC/min to 240ºC (10min) Column flow 1.2mL/min Pulse pressure 20 psi (4min) Scans Averaged 3 μScan Emission current 50 μAmps Electron Multiplier offset +300 V

Table 3.2-5 Nitrosamines and their corresponding retention time Retention Time Ions Compound Formula MW (min.) Monitored

N-nitrosodimethylamine (NDMA) C2H6N2O 74 9.4 75

N-nitrosodimethylamine-d6 C2D6N2O 80 9.4 81 N-nitrosomethylethylamine C H N O 88 10.4 89 (NMEA) 3 8 2

N-nitrosodiethylamine (NDEA) C4H10N2O 102 11.1 103 N-nitrosodi-n-propylamine C H N O 130 12.9 131 (NDPA) 6 14 2

N-nitrosopiperidine (NPIP) C5H10N2O 114 13.6 115

N-nitrosopyrrolidine (NPYR) C4H8N2O 100 13.4 101

N-nitrosodibutylamine (NDBA) C8H18N2O 158 14.6 159

N-nitrosomorpholine (NMOR) C4H8N2O2 116 13.2 117

Table 3.2-6 Method Detection Limits (ng/L) of nitrosamines on GC/MS Analyte AVE(ng/L) STDEV(ng/L) MDL(ng/L) NDMA 0.8 0.2 0.7 NMEA 1.2 0.1 0.2 NDEA 0.8 0.1 0.3 NPRO 1.1 0.1 0.3 NPIP 1.1 0.1 0.4 NPYR 1.0 0.1 0.2 NDBA 0.8 0.1 0.3 NMOR 0.6 0.2 0.6

3.2.2.4 Other methods and instruments

Free chlorine (HOCl), monochloramine (NH2Cl) and total chlorine were measured using a DR 2800 spectrophotometer HACH® kit. The range of detection limit for free and total chlorine was 0.02~2 mg/L as Cl2 and for monochloramine was 0.02 ~4 mg/L as Cl2. For samples with chlorine concentration above the upper detection limit of the HACH® kit, dilution was performed with Milli®-Q water.

For some experiments, the organic chloramines were measured as combined chlorine with the HACH® kit indirectly. The samples were analyzed for HOCl, NH2Cl and total chlorine and the combined chlorine concentration was estimated as the difference between total chlorine, HOCl and NH2Cl. Since pH of all the test samples was controlled approximately at 7.5, it is reasonable to assume that dichloramine and trichloramine species were negligible (Yoon and Jensen, 1993).

TOC samples were analyzed within 1 hour or were acidified with sulfuric acid for temporary preservation after the sample was taken to laboratory. TOC samples of swimming pool water were not filtered in the consideration of possible wash out of organic compounds from filter due to high concentration of free chlorine in swimming pool samples. However, TOC samples were measured out from the center of the container to avoid sampling of particle substance. In addition, other analytical methods that were employed to define water quality are summarized in Table 3.2-7.

Table 3.2-7 Other analytical methods used in this thesis Analyte Measuring unit Instrument /procedure Reference method TOC mg/L O1-Analytical TOC analyzer SM 5310 C pH N/A pH meter N/A Hewlett Packard 8452A Diode Array UVA cm-1 SM 5910B 254 UV spectrophotometer SUVA L/mg/cm N/A N/A Dionex DX-300 Series Ion Bromide µg/L SM 4110 B Chromatography System Note: SM means EPA Standard Method (APHA-AWWA-WEF, 2005); N/A mean not applicable.

3.2.3 QA/QC protocol

For the purpose of QA/QC, all glassware used for chlorination experiments were made chlorine demand free by filling the clean glassware with approximately 1 mL 6% NaOCl and deionized water and leaving them in the dark for 24 hours. The glassware was then rinsed three times with deionized water followed by two rinses with Milli-Q® water and then dried in the oven at approximately 250°C for 4 hours. Chemicals used in this thesis were at least of analytical grade (except one PCP compound behentrimonium chloride was not available at analytical grade) were chemical and high purity solvents (HPLC grade) were used in analysis.

During the analysis of DBPs (including THMs, HAA9, and nitrosamines), surrogate standards were used to correct any errors from the extraction and instrumental analysis. Calibration standards in the range representative of actual sample concentrations were analyzed with water samples containing analyte of interest. Check standards for organic chloramine, THMs, HAA9 and nitrosamines were also run within the sample list to ensure the quality control. QC charts were shown in Appendix 9.1. In addition, check standard solvent blank was also run ahead of samples to ensure there was no contamination in the solvent and from the background of instruments.

All of the experiments were conducted in triplicates in order to evaluate test variability and determine the errors associated with THMs, HAA9, nitrosamines and disinfectant residual measurements.

Total student t-test was performed on the results of THMs, HAA9 and individual nitrosamines in each set of swimming pool samples spiked with BFA compounds or PCP additives in Part III and Part IV. This is performed for the dtermination of the significance of the influence from each compound on DBP formation. Test results are shown as tables of p-value in Appendix 9.4.

Chapter 4 Water characterization and preliminary tests

Water characterization and preliminary tests

Experiments conducted in this section included sampling on selected swimming pools (Part I), experimenting on simulated swimming pool water using Body Fluid Analogue (BFA) base mix compounds (Part II), as well as potential and influence of PCP additives to affect disinfection byproduct formation. Parameters measured for swimming pool water included physical and chemical parameters, such as temperature, chlorine concentration, pH, total organic carbon (TOC), ultraviolet absorbance at 254 nm (UV254), and disinfection byproducts (DBPs). The discussion considers general operating information of different types of swimming pools and their physical and chemical parameters.

4.1 Selection of swimming pools

Swimming pools sampled in this study included indoor and outdoor swimming pools. As well, different types of swimming pools, such as on campus pools and community based pools; recreational pools and hot tubs, were sampled. All of the swimming pools sampled in this study are using similar operating technologies, which limits the choices that can be made in terms of optimizing operating technologies, as discussed in later sections.

4.1.1 Indoor swimming pools

Indoor swimming pools selected for this study included on campus pools and community based pools. They are labeled as In1 to In5, which can be grouped into on campus pools (In1 to In3) and community pools (In4 and In5). General pool operational parameters, such as volume, circulating frequency, and concentration of applied

43 chemicals, such as disinfectant concentration, pH value are shown in Table 4.1-1 below.

All indoor pools are controlled at temperature of 27 degrees Celsius and use tap water as their source water. The pH of swimming pool water is also automatically controlled at approximately 7.5 using muriatic acid (HCl). Free chlorine normally is automatically maintained using 12% sodium hypochlorite. When the total chlorine concentration reaches approximately 2.5 mg/L, it is considered time to shock the pool by raising the free chlorine concentration to 10 mg/L for 24 hours or, in case of In1 pool, potassium monopersulfate is used as shocking reagent to oxidize combined chlorine. No stabilizer is used in any of the indoor pools.

General schematic of the swimming pool treatment system is shown in Figure 4.1-1. Swimming pool water is circulated in the system four times per day. Most of the water (80%) is circulated through the skimmer and other portion flows to the drain. Water circulates through filter and is heat exchanged through the exchanger followed by being chlorinated and pH or hardness, alkalinity adjusted before it is pumped back into the pool through jets. Normally, swimming pool operators will thoroughly drain out the pool twice a year to clean and refresh the pool.

For swimming pools operated with hardness and alkalinity adjustment, hardness of

200-250 mg/L as CaCO3 and alkalinity of 80-130 mg/L as CaCO3 are maintained in the pool water. Hardness control is helpful for protecting the pool wall from etching. But too high hardness will cause scaling and cloudy water. Hardness control is not necessary when a vinyl liner is used. Alkalinity is helpful for maintaining the pH approximately at 7.5 (7.4 to 7.6), which prevent corrosion from low pH and avoid scaling from high pH. In addition, pH control helps maintain disinfection effectiveness. Normally, muriatic acid is used for pH adjustment.

Table 4.1-1Operational parameters of selected indoor swimming pools Volume pH Hardness and Circulating Replacement rate ID Type Disinfectant Filter type (Liter) adjustment alkalinity adjustment times per day (Liter/bather)

In1 On campus 400,000 NaOCl Yes, HCl Yes, CaCl2, NaHCO3 Rapid sand 4 20 Filter pad In2 On campus 1000,000 NaOCl Yes, HCl Yes, CaCl , NaHCO 4 20 2 3 with D.E.

In3 On campus 400,000 NaOCl Yes, HCl Yes, CaCl2, NaHCO3 Rapid sand 4 20 In4 Community 400,000 NaOCl Yes, HCl No Rapid sand 4 20 In5 Community 400,000 NaOCl Yes, HCl No Rapid sand 4 20 Note: D.E. means diatomaceous earth. It is added into the circulated pool water to help particle and microorganism removal. Water dosed with D.E. will be passed through filter pads, where D.E will be separated from the water.

Figure 4.1-1 General schematic of swimming pool treatment processes

4.1.2 Outdoor swimming pools

Three outdoor swimming pools were selected for this study. They were labeled as Out1 to Out3. Among them, Out3 is a hot tub whose operating temperature is higher than usual pool at 30 degrees Celsius. Pool stabilizer (cyanuric acid) is normally added at concentration of 30 mg/L in outdoor swimming pools to protect free chlorine from photolysis due to direct sun irradiation. Other than that, all other operating parameters are similar to those of indoor swimming pools.

Generally speaking, outdoor swimming pools have higher bather load since they are often run in summer time when children are out of school. Higher bather load consequently means higher organic matter input from bathers, and thus, higher concentrations of DBPs are expected.

Table 4.1-2Operational parameters of selected outdoor swimming pools Volume pH Hardness and Circulating Replacement rate ID Type Disinfectant Filter type (Liter) adjustment alkalinity adjustment times per day (Liter/bather) Out1 Community 400,000 NaOCl Yes, HCl No Rapid sand 4 20 Out2 Community 500,000 NaOCl Yes, HCl No Rapid sand. 4 20 Out3 Hot tub 100,000 NaOCl Yes, HCl No Rapid sand 4 20

4.2 Ambient water quality of swimming pools (Part I)

Swimming pool samples are typically clear but with a strong chlorine odor. In addition, there was likely some suspended particles from swimmers. It is important to avoid the sampling of those particles since it will influence the measurements. Considering most of the particles tend to move towards the skimmer and surface, an ideal sampling site was away from the skimmer by submerging the container under the water to get samples. It was also better to avoid direct sampling from the jets since these samples could have been diluted by added replacement tap water. The temperature of pool water was measured on-site and other parameters were measured in laboratory immediately upon arriving at the laboratory, which normally was within 1 hour. Samples were kept in the walk-in refrigerator consistently controlled at 4 degree, before further experiments and DBP analysis (which was performed within 24 hours).

DBP formation in swimming pool bulk water was expected to be complicated given that the components of organic input from swimmers are complicated including perspiration, saliva, cosmetics, etc. In order to produce a general spectrum of DBP concentration in public swimming pool water, survey sampling was conducted on selected swimming pools to identify possible influential factors which contribute to the formation of DBPs in swimming pool water. Results of this initial survey were used to help the understanding of DBP formation in swimming pool bulk water and inform later experiment processes.

4.2.1 Concentrations of DBPs in swimming pool water

Five indoor swimming pools and three outdoor swimming pools were sampled for the measurement of physical and chemical parameters, as well as DBP concentrations. Indoor swimming pools were selected from possible campus and community centers. Outdoor swimming pools were all selected from community centers given that no-campus outdoor swimming pools were found close by. However, different types of

49 outdoor swimming pool were selected, including a hot tub, a normal outdoor poor, and a deep diving pool.

Measured physical and chemical parameters included free chlorine, total chlorine, pH, temperature, UV254, TOC. Measured DBP categories included organic chloramines

(sometimes measured as combined chlorine), THMs, HAA9, and nitrosamines. Results are shown in Tables 4.2-1 to 4.2-4. Each table represents the results for one type of swimming pool (on campus indoor swimming pool, community center indoor swimming pool, community outdoor swimming pool and community outdoor hot tub). Results for more pools are shown in Appendix 9.2.

Generally speaking, bather load was approximately 100 bathers per day for the indoor swimming pools whereas it ranged from 200 to 500 bathers per day for normal outdoor pools. For the outdoor hot tub, bather load ranged more widely from 400 to 1200 persons per day. Most of the swimming pools use rapid sand filtration as the only treatment process followed by automatic control of the disinfectant concentration (normally using NaOCl), pH, alkalinity, hardness, and temperature. Some of the pools used a vinyl liner as a protective layer on the inside surface of the pool. In that case, there was no adjustment of hardness. Considering the inertness of the liner, is should have little influence, if any, on the consumption of disinfectant and the formation of DBPs.

Results show that indoor pool water, generally, has lower concentrations of DBPs than that of outdoor swimming pool water. This is logical because outdoor swimming pools normally operate during summer time, which consequently means higher bather loads, and people excrete more perspiration during the summer time.

Table 4.2-1 Measurements of indoor swimming pool (In2) on campus

January 14 January 25 February 01 April 09 Sampling date 2010 (1) 2010 (1) 2010 2010 (1) Approx. bather load 90 100 130 110 Free chlorine (mg/L) 1.95 2.86 2.50 1.80 Total chlorine (mg/L) 2.40 3.56 3.48 2.55 Monochloramine (mg/L) 0.03 0.06 0.06

HAA9 (µg/L) 543 422 243 499 NDMA (ng/L) 3.6 9.8 7.2 4.8 NDBA (ng/L)

(1): During these sampling dates, there had recently been or there was an ongoing training course of a group of about 30 bathers.

Table 4.2-2 Measurements of community indoor swimming pool (In4)

Sampling date April 26 2010 May 14 2010 Approx. bather load 70 50 Free chlorine (mg/L) 2.35 1.85 Total chlorine (mg/L) 2.80 2.35 Monochloramine (mg/L)

Table 4.2-3 Measurements of community outdoor swimming pool (Out1)

July 30 August 04 August 17 August 18 Sampling date 2010 2010 2010 2010 Approx. bather load 400 400 200 200 Free chlorine (mg/L) 8.70 2.28 0.05 0.95 Total chlorine (mg/L) 9.65 2.46 0.10 1.08 Monochloramine (mg/L) 0.01 0.01

HAA9 (µg/L) 621 562 174 144 NDMA (ng/L) 4.88 5.42 3.24 3.42 NDBA (ng/L)

Table 4.2-4 Measurements of outdoor hot tub (Out3)

August 09 August 12 August 17 August 18 Sampling Date 2010 2010 2010 2010 Approx. bather load 800 900 1000 300 Free chlorine (mg/L) 4.25 6.08 9.10 5.78 Total chlorine (mg/L) 5.78 7.53 11.95 7.18 Monochloramine (mg/L) 0.01 0.01 0.01 0.01 Free ammonia (mg/L)

HAA9 1561 974 2777 2267 NDMA (ng/L) 8.0 14.6

4.2.2 Discussion of typical results

The results of one indoor swimming pool (In2) are analyzed to provide an overview of possible relationships between water parameters and DBP formation in swimming pool bulk water. The discussion includes TOC and SUVA, organic chloramines and nitrosamines, THMs and HAAs. Results from the other pools followed similar trends and formed the basis for subsequent tests.

4.2.2.1 TOC and SUVA

Given that swimmers are the greatest sources of organic matter input, TOC values should be closely related to bather load. In this study, TOC samples were analyzed within 1 hour or were acidified with sulfuric acid for temporary preservation after the sample was taken to laboratory. However, as shown in Figure 4.2-1, TOC values were not related to bather load. TOC values were quite constant in this swimming pool despite changes in the bather load.

TOC (mg/L) Bather load 5.0 140

120 4.0

100

3.0 80

2.0 60 TOC TOC (mg/L)

40 Bather load (person)Batherload 1.0 20

0.0 0 Jan 14 2010 Jan 25 2010 Feb 01 2010 April 09 2010

Figure 4.2-1 Relation between TOC value and bather load of indoor swimming pool In2

Considering that pool water is continuously circulating through the filter and other water quality adjustment processes, the stable TOC value indicates that organic matter

55 input could be well controlled by the operating system while bather load is within the designed capacity. This would indicate that the concentration of some TOC contributing compounds from bathers could be fairly stable, whereas other portions of organic input from bathers could be quickly degraded or removed by the treatment processes. The stable TOC value also supports that the main factor controlling TOC value would be the replacement rate of the pool water, which is normally at 20 liter/bather. With every bather, 20 liter fresh tap water is added into pool water and 20 liter contaminated pool water is drained out of the pool. In addition, fresh tap water is added to make up for vaporization and splash losses.

In addition, a stable TOC value could also indicate that TOC input from individual swimmers could be fairly low compared to the large volume of the pool, thus no significant fluctuation can be observed with the fluctuation of bather load. However, for swimming pools with higher bather load per 1000 liter, TOC value is higher on average. As shown in Figure 4.2-2, the higher bather load per 1000 liter of about 0.21 corresponds to a higher TOC value of about 5.8 mg/L in pool In1. Similarly, the lower bather load per 1000 liter pool water of about 0.11 corresponds to a lower TOC value of about 4.2 in pool In2.

In2 In1 In2 bather load/1000L In1 bather load/1000L

6.0 0.28

4.5 0.21

3.0 0.14 TOC (mg/L) TOC

1.5 0.07 L load/1000 Bather

0.0 0.00 Jan 14 2010 Jan 25 2010 Feb 01 2010

Figure 4.2-2 Comparison of TOC values between indoor pool In1 and In2

In addition, research has indicated that the UV254, a parameter of aromatic and/or hydrophobic matter, can be used as surrogates for THM and HAA formation (Harrington et al., 1992; Traina et al., 1990), given that DBP formation increases with the activated aromatic content of natural organic matter (NOM) (Reckhow et al., 1990). The aromatic content of NOM can also be normalized to its TOC content to generate a SUVA value (Specific Ultraviolet Absorbance), which is the ratio of UV254 absorbance expressed in cm-1 divided by the TOC concentration expressed in mg/L. Therefore, SUVA has also been used as a surrogate for dissolved organic matter (DOM) reactivity and composition (Archer and Singer, 2006a, b; Weishaar et al., 2003). In this study, when bather load was within the designed pool capacity, SUVA values did not show significant changes in spite of bather load changes, as shown in Figure 4.2-3. As well, all of the swimming pools had relatively low SUVA values of 0.005 to 0.007 L/mg/cm, which implied that swimming pool water had low proportion of aromatic matter and should correspond to low formation of THMs and HAAs (to be discussed in Section 4.2.2.3).

SUVA Bather load 0.008 140

120 0.006

100

80 0.004

60 Bather load Bather

SUVA (L/mg/cm) SUVA 40 0.002 20

0.000 0 Jan 14 2010 Jan 25 2010 Feb 01 2010 April 09 2010

Figure 4.2-3 Relation between SUVA value and bather load of indoor swimming pool (In2)

4.2.2.2 Organic chloramine and nitrosamines

Considering molecular structure similarity of organic chloramines and nitrosamines,

57 their possible formation in swimming pool bulk water and possible relationship with organic compounds provided by bather is discussed below. In this section, only NDMA, NDBA, and NDEA are discussed since other nitrosamines were only occasionally detected in a few of the swimming pools. As shown in Figures 4.2-4 to Figure 4.2-6, high bather load corresponds to neither high concentrations of organic chloramines nor to higher concentrations of nitrosamines. This indicates that, in swimming pools, factors influencing the formation of organic chloramines and nitrosamines not only include the amount of input of organic compounds from bathers, but also could include other factors, such as the types of organic input.

140

120

100

40 Bather load (person) load Bather

0 Jan 14 2010 Jan 25 2010 Feb 01 2010 April 09 2010

Figure 4.2-4 Bather loads of indoor swimming pool (In2) on sampling days

However, as shown in Figure 4.2-5 and Figure 4.2-6, organic chloramines and nitrosamines show opposite formation trends in swimming pool water. High formation of organic chloramines corresponds to low concentration of nitrosamines and vice versa. For example, on the January 25, 2010 sampling day, the concentration of organic chloramines was the lowest at 0.1 mg/L in indoor swimming pool In2 water, whereas the concentrations of nitrosamines (NDMA, NDBA, NDEA) were the highest at 10 ng/L, 22 ng/L, 22 ng/L, respectively.

Nonetheless, considering the low concentration of NDMA, NDBA and NDEA, more

58 studies are needed to further confirm aforementioned conclusion.

NDMA NDBA Chart TitleNDEA Organic chloramine

25 0.6

0.5 20

0.4 15 0.3 10 0.2

Nitrosamine concentration(ng/L) 0.1 Organicchloramine concentration (mg/L) 0 0.0 Jan 14 2010 Jan 25 2010 Feb 01 2010 April 09 2010

Figure 4.2-5 Concentration of nitrosamines (NDMA, NDBA, NDEA) along with concentration of

organic chloramines in indoor swimming pool (In2)

4.2.2.3 Discussion related to THMs and HAAs

The Formation of THMs and HAAs in swimming pools and their relationship with bather load is discussed below. Results show that bather load generally has a direct influence on the formation of THMs and HAAs, as shown in Figures 4.2-7 and 4.2-8. The highest bather load, on February 01, 2010, corresponded to the highest formation of THMs and HAAs.

THMs Bather load

500 150

g/L) 400 120

300 90

200 60 Bather (person) load

TTHMconcentration ( 100 30

0 0 Jan 14 2010 Jan 25 2010 Feb 01 2010 April 09 2010

Figure 4.2-6 Concentration of THMs along with bather load of indoor swimming pool (In2)

Bather load MCAA DCAA TCAA HAA9 500

400

g/L) μ 300

200

Concentration ( Concentration 100

0 Jan 14 Jan 25 Feb 01 2010 April 09 2010 2010 2010

Figure 4.2-7 Concentration of, MCAA, DCAA, TCAA, and HAA9 along with bather load in indoor

swimming pool (In3)

However, the HAA results did not always well-correspond to bather load in some swimming pools, especially when there was a sharp increase of bather load during the sampling, such as when there was a group training course in the indoor swimming pool or when groups of people stormed into an outdoor pool right before the sampling. This

60 can be observed from the results of other swimming pools in Appendix 9.2. However, the concentrations of THMs could be lower when there was group training or a sudden increase of bathers, given the high volatility of THMs with disturbance and splashing of swimming pool water. Nonetheless, THMs and HAAs were observed to be readily formed from the organic compounds provided by swimmers under typical condition of swimming pool (normally characterized with high free chlorine concentration of 1.5 mg/L and high temperature of at least 27 degrees Celsius.

In addition, THM and HAA concentrations in pool water were quite high at hundreds of µg/L in indoor pool water and few thousand µg/L in outdoor pool water. This was not surprising since TOC concentration can also be used a surrogate for THM and HAA formation (Harrington et al., 1992; Traina et al., 1990). And, as reported by Ates et al. (2007), THMs and HAAs can be formed from low- or none-UV-absorbing NOM in waters with low SUVA. Therefore, given the values of TOC were high at 3 to5 mg/L in indoor pools and up to 10 mg/L in hot tub, it was not surprising to see the high formation of THMs and HAAs.

4.2.3 Effects of shocking treatment

When a ―chlorine‖ odor emanates from pool water or when swimmers experience some skin and eye irritation, it could be due to extensive formation of combined chlorine or chloramines. This could also be confirmed when there is a quick drop in the free chlorine residual. In order to maintain the healthiness of the pool, it is necessary to shock the pool to remove chloramines as well as to inactivate resistant organisms in the water. Shocking treatment also helps to raise the free chlorine concentration to maintain the effectiveness of disinfection.

Two types of shocking treatment processes are normally applied to swimming pool water. One method uses higher doses (normally 8 to 10 mg/L) of free chlorine to shock the pool for at least 24 hours followed by closing the pool for a few days to let the concentration of free chlorine drop down to normal operating concentrations

61 approximately 1.5 mg/L). The other method, which is faster and more convenient, uses chemicals with a high oxidant potential, such as sodium monopersulfate (NaHSO5), to oxidize the organic chloramines and combined chlorine in a short time. Theoretically, it only takes 1 to 2 hours to re-open the pool.

Although shocking treatment is usually mainly to inactivate resistant organisms and bring back the free chlorine concentrations by breaking down combined chlorine, there may be concurrent chemical oxidation of organics including natural organic matter and DBPs. In this study, only the monopersulfate method was investigated in terms of its effect on removing organic matter and DBPs. Results are summarized in Table 4.2-5. Higher free and total chlorine were observed due to the influence of monopersulfate on the measurements of DPD method.

Table 4.2-5 Measurements of In1 swimming pool water before and after shocking treatment

January 05 2010 February 01 2010 April 09 2010 Sampling date Before After Before After Before After Approx. bather load 80 80 110 110 120 120 Free chlorine (mg/L) 1.75 2.09 1.35 2.33 1.80 2.25 Total chlorine (mg/L) 3.06 6.70 2.88 6.70 3.05 6.25 Monochloramine (mg/L) 0.03 0.03 0.06 0.06

BDCAA (µg/L) 0.3

HAA9 (µg/L) 224 218 185 167 310 336 NDMA (ng/L) 0.9 1.2 6.3 7.3 1.6 0.9 NDBA (ng/L)

Comparison of the results in Figures 4.2-8 to 4.2-12 illustrate the effects of shocking treatment by sodium monopersulfate on DBP concentrations and TOC in swimming pool water. As shown in Figure 4.2-8, shocking treatment by sodium monopersulfate significantly decreased the concentration of organic chloramines. The measurement of organic chloramines was conducted 1 day after socking to avoid the influence of the shocking chemicals on the measurement of organic chloramines due to its high oxidant potential. However, as shown in Figures 4.2-9 to 4.2-12, no significant removal of TOC and other DBPs, such as THMs, HAAs, and NDMA can be observed based on this study. This indicates that monopersulfate is not strong enough to oxidize NOM or DBPs directly.

Before shocking treatment After shocking treatment 1.0

0.8

0.6

(mg/L) 0.4

0.2

Organic chloramine concentration chloramine Organic 0.0 January 05 2010 February 01 2010 April 09 2010

Figure 4.2-8 Effects of shocking treatment on organic chloramines in indoor swimming pool (In1)

Before shocking treatment After shocking treatment 7

3 TOC (mg/L) TOC 2

0 January 05 2010 February 01 2010 April 09 2010

Figure 4.2-9 TOC before and after shocking treatment in indoor swimming pool (In1)

Before shocking treatment After shocking treatment

350

300

250

200

150

100 TTHM Concentration (µg/L) Concentration TTHM 50

0 January 05 2010 February 01 2010 April 09 2010

Figure 4.2-10 THMs before and after shocking treatment in indoor swimming pool (In1)

Before shocking treatment After shocking treatment

400

300

200

100 HAA9 concentration(µg/L) HAA9

0 January 05 2010 February 01 2010 April 09 2010

Figure 4.2-11 HAA9 before and after shocking treatment in indoor swimming pool (In1)

Before shocking treatment After shocking treatment

2 NDMA Concentration (ng/L) Concentration NDMA

0 January 05 2010 February 01 2010 April 09 2010

Figure 4.2-12 NDMA before and after shocking treatment in indoor swimming pool (In1)

4.2.4 Comparison of indoor swimming pools versus outdoor

swimming pools

Indoor swimming pools are different from outdoor swimming pools in terms of their operating period. Indoor swimming pools are normally open all year around. Outdoor swimming pools could only be open during summer time in Ontario. However, outdoor swimming pools normally have a heavier bather load given the hot summer weather and the desire for people to cool off. Thus, there could be a difference in water quality even when similar operating and treatment technologies are applied. Comparison of their physical and chemical parameters, as well as the concentrations of DBPs in bulk water would help in the understanding and optimization of operating technologies. For the pools investigated in this study, parameters such as bather load per 1000 liter of pool water, TOC value, SUVA, and concentrations of THMs, HAA9, and NDMA were compared.

Generally speaking, bather loads per 1000 liter water and TOC values exhibited similar trends between indoor and outdoor swimming pools as shown in Figures 4.2-13 and 4.2-14. This is consistent with previous discussion in Section 4.2.2. Also, during the summer time, swimming pools would be more popular than at other times which would mean higher bather loads per 1000 liter pool water. During the time, swimmers would release more body fluid and more personal care products, such as sweat and sunscreen. This input of organic matter would potentially increase the TOC. As a result, high unit bather loads correspond to higher TOC values in pool bulk water. It should be noted that the third outdoor swimming pool (Out3) is a hot tub which had a much higher bather load than any other pool. As a result, as shown in Figure 4.2-14, its TOC values were much higher than for other swimming pools. However, all swimming pools showed a relatively stable level of TOC during all sampling days. Given that the pools were operating regularly through all sampling days, the small variation could come from sampling errors or uneven bather loads. Nonetheless, based on the stable TOC values, turnover and replacement rates for the pool water appeared to maintain the

66 steady state and keep the TOC value relatively constant rather than having it being greatly influenced by the bather load. This is consistent with previous results in Section 4.2.2.

8 9 10

2.0

1.6

1.2

0.8

Bather load/1000 liter load/1000 Bather 0.4

0.0 Out3Out2 Out1 In5 In4 In3 Day 3 In2 Day 2 In1 Day 1

Figure 4.2-13 Bather load per 1000 liter pool water of different types of swimming pools (outdoor

pools 1-3, indoor pools 1-5)

8 TOC (mg/L) TOC

0 Out3Out2 Out1 In5 In4 In3 In2 DayDay 2 3 In1 Day 1

Figure 4.2-14 TOC value comparison of different types of swimming pools (outdoor pools 1-3,

indoor pools 1-5)

Concentration of THMs and HAA9 have similar trends to that of bather load per 1000 liter pool water and the TOC values, as shown in Figures 4.2-15 and 4.2-16. Generally speaking, higher concentrations of THMs and HAA9 were present in outdoor swimming pools, especially for pool Out3 which had much higher bather loads per 1000 liter water. This is consistent with the discussion in Section 4.2.2 where THM and HAA concentrations corresponded to bather loads on different sampling days. However, increments of THM concentrations were more obvious than of HAA concentrations when comparing outdoor pools with indoor pools. This implies that, in outdoor pools, THMs may more readily formed from precursors such as body fluids or sunscreen given that, normally, outdoor swimmers excrete more body fluid and use more sunscreen than indoor swimmers.

1000

800

600

400 TTHM (µg/L) TTHM

200

0 Out3Out2 Out1 In5 In4 In3 Day 3 In2 Day 2 In1 Day 1

Figure 4.2-15 THM value comparison of different types of swimming pools (outdoor pools 1-3,

indoor pools 1-5)

3000

2400

1800

1200 HAA9 (µg/L) HAA9

600

0 Out3Out2 Out1 In5 In4 In3 Day 3 In2 Day 2 In1 Day 1

Figure 4.2-16 HAA9 value comparison of different types of swimming pools (outdoor pools 1-3,

indoor pools 1-5)

SUVA has been used as a surrogate for dissolved organic matter (DOM) reactivity and composition (Archer and Singer, 2006a, b; Weishaar et al., 2003). In this study, as shown in Figure 4.2-17, SUVA values were neither corresponding to bather load per 1000 liter water (Figure 4.2-13) nor corresponding to THM or HAA (Figures 4.2-15 and 4.2-16) formation. This implies that reactivity of swimming pool water and DBP formation in swimming pool relies on other types of organic compounds, such as body fluid and personal care products, rather than NOM. Low SUVA value supports the necessity of investigating of BFA and PCP additives as potential DBP precursor in swimming pool bulk water.

0.010

0.008

0.006

0.004

0.002 SUVA (L/mg/cm) SUVA

0.000 Out3Out2 Out1 In5 In4 In3 Day 3 In2 Day 2 In1 Day 1

Figure 4.2-17 SUVA value comparison of different types of swimming pools (outdoor pools 1-3,

indoor pools 1-5)

Concentrations of NDMA were similarly low in both indoor and outdoor swimming pools as shown in Figure 4.2-18. However, other species of nitrosamines, such as NDBA and NDEA showed much higher concentrations in outdoor swimming pools. This indicates that there could be potential precursors for other species of nitrosamines in swimming pool water. On the other hand, given that all of these pools were chlorinated, and chlorination is not as favorable as chloramination for the formation of nitrosamine, low concentrations of NDMA could be reasonable. In addition, low concentrations of NDMA implied a low NDMA formation potential from body fluid and personal care products (sunscreen and body lotion), whereas they could be potential precursor of other nitrosamine species or could promote formation of other nitrosamines. This was further investigated in later experiments (Chapter 5).

10 NDMA (ng/L) NDMA

0 Out3 Out2 Out1 In5 In4 In3 Day 3 In2 Day 2 In1 Day 1

Figure 4.2-18 NDMA value comparison of different types of swimming pools (outdoor pools 1-3,

indoor pools 1-5)

4.2.5 Summary

Different types of swimming pools were sampled for the measurement of physical and chemical parameters as well as the formation of DBPs in swimming pool bulk water. Given the existence of similar treatment processes and operating technologies for all of the pools, the main differences observed were due to bather load and operating circumstance (outdoor or indoor). Measurements showed that higher DBP formation came from higher organic inputs from swimmers. The outdoor hot tub (Out3) had the highest DBP formation from the highest bather load.

Measurements also showed that changes in bather load during sampling did not have an instant influence on TOC or SUVA values, nor did it have a positive relationship with changes in the concentrations of organic chloramines and nitrosamines. However, it did have a positive correlation with the formation of THMs and HAAs. There was also a possible relationship between organic chloramines and nitrosamines, which would be further investigated in Chapter 5.

71 4.3 Preliminary bench-scale experiment (Part II)

Body Fluid Analogue (BFA) base mix compounds were used to mimic the major organic compounds of swimming pool bulk water for further experiments. BFA base mix compounds included #1 (ammonium chloride), #2 (urea), #3 (L-histidine), #4 (hippuric acid), #5 (uric acid), #6 (citric acid), and #7 (creatinine). Concentrations in the stock solution as used in this study are shown in Table 4.3-1. They were chosen based on the observed pool TOC values and calculations of dilutions necessary for the base mix blend to achieve those concentrations. Results of the final contributions of each BFA compound to the solution TOC are shown in Table 4.3.2.

Table 4.3-1 Stock solution concentrations of BFA compounds (Judd et al., 2003) Ingredient mg/L Ammonium chloride 2000 Urea 14800 Histidine 1210 Hippuric acid 1710 Uric acid 490 Citric acid 640 Creatinine 1800

Since Personal Care Products (PCPs) would likely wash off the skin of swimmers as they entered a pool, PCP additives were also spiked into this base mix to investigate their influence on the formation of DBPs. PCP additives used in this study included A1 (Diethanolamine), A2 (Padimate O), A3 (Nitrilotriacetic acid), A4 (Triethanolamine), A5 (Tetrabutylammonium chloride), A6 (Cetyltrimethylammonium chloride), A7 (Choline chloride), A8 (Cocamidopropyl betaine), A9 (Behentrimonium chloride), and A10 (Tetramethylammonium chloride). Concentration of each additives used for this study was 1 mg/L, which contributed to the calculated TOC as shown in Table 4.3-2.

Table 4.3-2 Calculation of TOC for BFA base mix compounds and PCP additives in mg/L Molecular Weight Actual Concentration Molecular Calculated Name Code (g/mol) (mg/L) Formula TOC (mg/L)

Urea Base mix #2 60.06 14.8 CH4N2O 2.96

Histidine Base mix #3 155.15 1.21 C6H9N3O2 0.56

Hippuric acid Base mix #4 179.17 1.71 C9H9NO3 1.03

Uric acid Base mix #5 168 0.49 C5H4N4O3 0.18

Citric acid Base mix #6 192.124 0.64 C6H8O7 0.24

Creatinine Base mix #7 113.118 1.8 C4H7N3O 0.76

Diethanolamine (DELA) PCP A1 105.14 1.00 C4H11NO2 0.46

Padimate O PCP A2 277.402 1.00 C17H27NO2 0.74

Nitrilotriacetic acid PCP A3 191.14 1.00 C6H9NO6 0.38

Triethanolamine PCP A4 149.188 1.00 C6H15NO3 0.48

Tetrabutylammonium chloride PCP A5 277.914 1.00 (C4H9)4NCl 0.69

Cetyltrimethylammonium chloride PCP A6 320 1.00 C19H42ClN 0.71

Choline Chloride PCP A7 139.62 1.00 C5H14ClNO 0.43

Cocamidopropyl betaine PCP A8 342.52 1.00 C19H38N2O3 0.67 Behentrimonium chloride PCP A9 404.16 1.00 C H ClN 0.74 (BTAC-228) 25 54

Tetramethylammonium chloride PCP A10 109.6 1.00 C4H12NCl 0.44

Cyanuric acid Cy 129.07 30.00 C3H3N3O3 0.28 Humic acid H N/A 1.00 N/A N/A Note: N/A means not available due to the complexity of humic acid.

In addition to the BFA base mix compounds and PCP additives used in this study, cyanuric acid and humic acid were also investigated for possible effects on the formation of DBPs in simulated swimming pool water.

TOC values of simulated swimming pool water were prepared to be similar to the real TOC value measured for real swimming pool water, therefore providing a reasonable background of organic matter in simulated swimming pool water. Theoretical TOC values shown in Table 4.3-2 were calculated by the equation below.

Equation 4.3-1

Carbon atomic mass  Number of carbon atoms Theoretical TOC  ( ) Molecular weight of additive Actual mass concentration of additive (mg/L)

Based on this calculation, the concentration of BFA base mix compounds #2 to #7 in the table produced a total TOC of 5.73 mg/L, which was similar to the TOC value in most of the indoor swimming pools. Individual concentrations of PCP additives A1 to A10 of 1 mg/L provided a total TOC of 6.01 mg/L which was also a reasonable value to simulate the pool bulk water.

4.3.1 Free chlorine demand for BFA base mix compounds and PCP

additives

Organic compounds react with free chlorine to form combined chlorine as well as other DBPs. In order to simulate disinfectant concentration in real swimming pools, it is important to identify how much free chlorine will be consumed before relatively stable residual remains for the remaining period of reaction. This part of the experiment was conducted to measure the free chlorine demand for BFA base mix both with and without spiking with other PCP additives. This part of experiment also helped to identify the duration of the fast reaction period which produces the first part of free

74 chlorine demand in simulated pool water. The endpoint of fast reaction period was used as the point where the free chlorine concentration would be monitored as an initial concentration for subsequent experiments (Chapter 5). Lastly, the results of these free chlorine demand tests helped determine the incubation period for subsequent experiments (Chapter 5) to provide sufficient time for the completion of all the reactions in bulk water.

For the chlorine demand experiments, an arbitrarily high concentration of free chlorine (10 mg/L) was spiked into simulated swimming pool water containing BFA base mix compounds #1 to #7. Simulated swimming pool water spiked with 1 mg/L of PCP additives was also dosed with high concentration of free chlorine (10 mg/L). Concentrations of free chlorine and total chlorine were measured initially followed by measurements at time intervals of about 0.5 hours until 2.5 hours. Finally, free and total chlorine were measured at time point of approximately 8 hours. Results are shown in Table 4.3-3. Degradation curves of free chlorine and total chlorine were plotted in Figures 4.3-1 and 4.3-2. Combined chlorine was calculated from free and total chlorine and was plotted in Figure 4.3-3.

Table 4.3-3 Measurements of free chlorine and total chlorine in BFA simulated swimming pool

water spiked with PCP additives Time Free chlorine Total chlorine Combined chlorine ID (hour) (mg/L) (mg/L) (mg/L) 0.0 10 10

As shown in Figures 4.3-1 and 4.3-2, free and total chlorine decayed quickly at the beginning of the incubation period. After 1.5 hours, the decline of free and total chlorine appeared to be slow. As shown in Figure 4.3-3, most of the combined chlorine formation was accomplished within 1.5 hours. Following the fast reaction period, little fluctuation of combined chlorine was observed until the end of the incubation. It can be concluded that the formation of most of the combined chlorine was established within 1.5 hours in simulated swimming pool water matrix. Following the fast reaction period,

76 other reactions with slower kinetics, such as the formation of more stable combined chlorine species and DBP formation, would be the primary reason for free chlorine consumption.

In addition, as shown in Figures 4.3-2, initial degradation slopes of total chlorine in samples spiked with cyanuric acid and PCP additives, such as (B+ A5- A8+ A10) and (B+A1-A4) are less steep than that of base mix alone. Degradation of free chlorine also exhibits similar trend as shown in Figure 4.3-1. This shows that addition of organic compounds (in this study, they are cyanuric acid and PCP additives) could potentially slows down degradation of free and total chlorine instead of causing more degradation.

Control (MilliQ water) Base mix Base mix + Cyanuric acid Base mix + A1-A4 Base mix +A5-A8,A10

3 Free Chlorine residual (mg/L) residual Chlorine Free

0 0.0 2.5 5.0 7.5 10.0 Time (hrs)

Figure 4.3-1 Free chlorine degradation in BFA simulated swimming pool water with/without PCP

additives

Control (MilliQ water) Base mix Base mix + Cyanuric acid Base mix + A1-A4 Base+A5-A8,A10

3 Total Chlorine residual (mg/L) residual Chlorine Total 0 0.0 2.5 5.0 7.5 10.0 Time (hrs)

Figure 4.3-2 Total chlorine degradation in BFA simulated swimming pool water with/without PCP

additives

Control (MilliQ water) Base mix Base mix + Cyanuric acid Base mix + A1-A4 Base+A5A8,A10

3.0

2.5

2.0

1.5

1.0

0.5

Combined Chlorine residual (mg/L) residual Chlorine Combined 0.0 0.0 2.5 5.0 7.5 10.0 Time (hrs)

Figure 4.3-3 Combined chlorine formation in BFA simulated swimming pool water with/without

PCP additives

Given that normal turnover time is about 3 hours for public swimming pools, for subsequent tests (Chapter 5) where swimming pool water was spiked with BFA compounds and PCP additives, 1.5 hours would be used as an initial state checking

78 point and at least of 1.5 mg/L free chlorine residual (a typical residual for swimming pools) would be maintained. Reaction time of 24 hours would be used to estimate the maximum concentration of disinfection byproducts in the swimming pool bulk water since at least 80% of DBP has been formed in 24 hours compared with in 72 hours (Summers et al., 1996).

4.3.2 Free chlorine breakpoint for BFAs and PCP additives

In order to investigate the effects of BFA and PCP compounds on DBP formation in swimming pool water matrix, it is necessary to ensure a presence of free chlorine residual in the bulk water made of Body Fluid Analogue (BFA) base mix compounds so it is similar to the real swimming pool water. Therefore, initial concentration of free chlorine applied should be enough to not only satisfy the demand from fast reactions but also provide a chlorine residual of at least 1.5 mg/L at 1.5 hours, which is similar to typical free chlorine concentration in swimming pools.

Two sets of experiments were conducted to examine the free chlorine demand. The first set experiment was conducted on groups of BFA base mix compounds and PCP additives. Different initial free chlorine concentrations, from 5 mg/L to 35 mg/L, were dosed into the samples followed by measurement of free chlorine residual at time of 3 hours and 24 hours. The difference between the initial dosage and residual concentrations represents the demand. The second set of experiments was conducted on individual BFA and PCP compounds. Both tests examined the general consumption of free chlorine from BFA base mix compounds and PCP additives.

In the first set of experiment, time points of 3 hours and 24 hours were selected as measuring points for the determination of residual free chlorine. Measurements at the 3 hour interval mainly represented the free chlorine consumption from fast reactions and measurements at the 24 hour interval mostly indicated the free chlorine demand for all of the reactions. As shown in Table 4.3-4 and Figure 4.3-4, the consumption of free chlorine after 3 hours was similar for each of the three groups of organic compounds.

Linear regression of last four measurements shows that, in order to provide 1.5 mg/L free chlorine residual at time of 3 hours, free chlorine demand of 9.5 mg/L, 10.3 mg/L, and 11.5 mg/L is required, which corresponds to BFA base mix + cyanuric acid, BFA base mix + A5-A8 + A10, and BFA base mix + A1-A4, respectively. This indicates that three groups of organic compounds have similar fast reaction kinetics.

Table 4.3-4 Free chlorine residual after 3 hours in different groups of BFA and BFA+PCP

compounds in simulated swimming pool water Initial Free Chlorine 5.00 10.00 15.00 20.00 25.00 35.00 Dose (mg/L) BFA base mix Free +cyanuric acid 0.1 1.25 4.8 8.2 12 20 chlorine BFA base mix residual +A1-A4 0.15 0.1 3.2 6.75 10.9 18.6 (mg/L) BFA base mix +A5-A8,A10 0.15 0.75 3.95 7.55 11.4 18.8

Base mix+Cyanuric acid Base mix+A1-A4 Base mix+A5-A8,A10

5 Residual free chlorine (mg/L) chlorine free Residual 0 0 5 10 15 20 25 30 35 40 Initial free chlorine (mg/L)

Figure 4.3-4 Free chlorine residual after 3 hours in different groups of BFA and BFA+PCP

compounds simulated swimming pool water

However, as shown in Table 4.3-5 and Figure 4.3-5, after 24 hours the three groups of organic compounds showed different demands of free chlorine. Linear regression of last two measurements shows that, in order to provide 1.5 mg/L free chlorine residual at

80 time of 24 hours, free chlorine demand of 23.5 mg/L, 27.5 mg/L, and 31.5 mg/L is required, which corresponds to BFA base mix + cyanuric acid, BFA base mix + A5-A8 + A10, and BFA base mix + A1-A4, respectively. It indicates that different groups of organic compounds which had similar reactivity during fast reaction period may exhibit different reaction kinetics in the slow reaction period as a result of the formation of more stable combined chlorine and disinfection byproducts.

Table 4.3-5 Free chlorine residual after 24 hours in different groups of BFA and BFA+PCP

compounds simulated swimming pool water Initial Free Chlorine 5.00 10.00 15.00 20.00 25.00 35.00 Dose (mg/L) BFA base mix Free +cyanuric acid 0.10 0.10 0.30 0.65 1.50 3.40 chlorine BFA base mix residual +A1-A4 0.15 0.10 0.15 0.15 0.45 1.75 (mg/L) BFA base mix +A5-A8,A10 0.15 0.10 0.20 0.30 0.85 2.45

Base mix+Cyanuric acid Base mix+A1-A4 Base mix+A5-A8,A10

4.0

3.0

2.0

1.0

Residual free chlorine (mg/L) chlorine free Residual 0.0 0 10 20 30 40 Initial free chlorine (mg/L)

Figure 4.3-5 Free chlorine residual after 24 hours in different groups of BFA and BFA+PCP

compounds simulated swimming pool water

In the second set of experiments, breakpoint experiments with individual BFA base mix compounds and PCP additives, mole ratios of Cl:N from 1:1 to 1:5 similar to ones in a

81 conventional breakpoint test were applied . A reaction period of approximately 2 hours was selected to mainly include the fast reactions. As a control experiment, results of the breakpoint measurement for ammonium chloride are shown in Table 4.3-6 and Figure 4.3-6. In comparison with a traditional breakpoint curve where the breakpoint normally occurs at a Cl:N molar ratio of 1.5:1, this experiment had a breakpoint occurring at a Cl:N molar ratio of 1.5-2.0. This was probably due to an insufficient number of data points in the breakpoint region. Nonetheless, information in the curve can still give us confident in the subsequent results.

Table 4.3-6 Breakpoint measurements for BFA compound #1 (ammonium chloride) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 0.5:1 1.33 0.08 1.38 1:1 2.65 0.12 2.34 1.5:1 3.98 0.08 1.17 2:1 5.31 0.42 0.47 3:1 7.96 2.26 2.52 Concentration of BFA compound #1 (ammonium chloride) was 2 mg/L with test time of 1.5 hours.

FCl TCl 3.0

2.5

2.0

1.5

1.0

Concentration (mg/L) Concentration 0.5

0.0 0 0.5 1 1.5 2 2.5 3 3.5 Cl:N mole ratio .

Figure 4.3-6 Breakpoint curve for BFA compound #1 ammonium chloride of 2 mg/L with time of

1.5 hours

Some of the additives formed combined chlorine, as estimated by the difference

82 between free and total chlorine residuals. Free chlorine breakpoint curves for BFA compound #3 (histidine), #7 (creatinine) and PCP additives A1 (diethanolamine), A4 (triethanolamine) are shown in Figures 4.3-7 to 4.3-10. Significant amount of combined chlorine was produced from them, but other BFA and PCP compounds did not show significant formation of combined chlorine (shown in Appendix 9.3). It might be because these compounds did not have significant potentials to form combined chlorine or they might produce combined chlorine but these combined chlorine compounds were not stable enough to resist being measured as free chlorine by DPD

Some of the additives exhibited significant initial free chlorine demand. As shown in Tables 4.3-7 to 4.3-10 and in Appendix 9.3, BFA #2 (urea), #3 (histidine), #5 (uric acid), #7 (creatinine), and PCP additives A1 (diethanolamine), A2 (Padimate O), A4 (triethanolamine), A6 (cetrytirmethylammonium chloride), and cyanuric acid exerted a chlorine demand within 1.5 to 2 hours. Difference between free chlorine dose and free chlorine residual represents the free chlorine demand. Free chlorine demand values combined with the results in section 4.3.1 were used to determine initial free chlorine dose for Chapter 5, where real swimming pool water was used as water matrix. Concentration of free chlorine was adjusted before any addition of BFA compounds or PCP additives to ensure a minimum free chlorine residual of 1.5 mg/L at 1.5 hours, which was used as the target resident to meet prior to the following 24 hours incubation period.

Table 4.3-7 Breakpoint measurements for BFA compound #3 (histidine) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.55 0.03 0.27 2:1 1.11 0.04 0.61 3:1 1.66 0.26 0.75 4:1 2.21 0.75 1.21 5:1 2.77 1.28 1.75 Concentration of BFA compound #3 (histidine ) was 1.21 mg/L with test time of 1.5 hours.

FCl TCl 2.0

1.6

1.2

0.8

0.4 Concentration (mg/L) Concentration

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 4.3-7 Breakpoint curve for 1.21 mg/L BFA compound #3 (histidine)

Table 4.3-8 Breakpoint measurements for BFA compound #7 (creatinine) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 1.13 0.08 0.58 2:1 2.26 0.43 1.08 3:1 3.39 0.93 1.58 4:1 4.52 1.43 2.13 5:1 5.65 1.84 2.59 Concentration of BFA compound #7 (creatinine) was 1.8 mg/L with test time of 1.5 hours.

FCl TCl 3.0

2.4

1.8

1.2

0.6 Concentration (mg/L) Concentration 0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 4.3-8 Breakpoint curve for 1.8 mg/L BFA compound #7 (creatinine)

Table 4.3-9 Breakpoint measurements for PCP additive A1 (diethanolamine) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.68 0.04 0.67 2:1 1.35 0.48 1.23 3:1 2.03 1.12 1.86 4:1 2.70 1.70 2.39 5:1 3.38 2.03 2.86 Concentration of PCP additive A1 (diethanolamine) was 1 mg/L with test time of 1.5 hours.

FCl TCl 3.5

2.8

2.1

1.4

0.7 Concentration (mg/L) Concentration

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 4.3-9 Breakpoint curve for 1 mg/L PCP additive A1 (diethanolamine)

Table 4.3-10 Breakpoint measurements for PCP additive A4 (triethanolamine) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.48 0.14 0.27 2:1 0.95 0.32 0.53 3:1 1.43 0.53 0.88 4:1 1.90 0.91 1.30 5:1 2.38 1.21 1.63 Concentration of PCP additive A4 (triethanolamine) was 1 mg/L with test time of 1.5 hours.

FCl TCl

2.0

1.6

1.2

0.8 Concentration (mg/L) Concentration 0.4

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 4.3-10 Breakpoint curve for 1 mg/L PCP additive A4 (triethanolamine)

In summary, when organic compounds were added into water with free chlorine, based on results of section 4.3.1and section 4.3-2, fast reactions would produce an instant chlorine demand and lead to the formation of unstable combined chlorine and some DBPs. If initial concentration of free chlorine was not high enough to meet the chlorine demand from all the fast reactions, then some of the unstable combined chlorine could release Cl+ to supply a further free chlorine demand. On the other hand, if initial concentration of free chlorine was high enough, then not only chlorine demand from the fast reactions would be satisfied, it can also be enough for ―slow‖ reactions to form DBPs and more stable combined chlorine in the system. Results of these two sections by determining chlorine demand and breakpoint curves ensured next-step experiments to be proceeded efficiently.

4.3.3 Disinfection byproducts in simulated swimming pool bulk

water with chlorination

As a further preliminary experiment, the formation of disinfection byproducts in simulated swimming pool water matrix was investigated. The same mixture of body fluid analogues (BFAs) was used as the fundamental water matrix (base mix). PCP

86 additives were added into the base mix for the purpose of investigating their impacts on DBP formation.

BFA base mix compounds were combined to create the fundamental water matrix for simulated swimming pool water for this part of experiment and their concentrations are shown in Table 4.3-2. PCP additives of 1 mg/L were added into the simulated swimming pool water individually or in groups to determine their potential effects on the formation of DBPs. A high initial free chlorine concentration of 50 mg/L was used considering that there could be a high demand of free chlorine during the arbitrarily long period of 5-day incubation, which ensures attaining of equilibrium values of DBP formation (Judd and Black, 2000). Results of this part of experiments could provide the information about the formation potential of simulated swimming pool water with/without PCP additives, and also further confirm the chlorine demand results in previous sections. Amber bottles (1 liter) were used as reactors at room temperature, which is similar to the conditions in a real swimming pool.

Two sets of experiments were conducted to investigate DBP formation in simulated swimming pool water. First set of experiments was carried on groups of additives, namely, control (MilliQ water), BFA base mix (B), BFA base mix + cyanuric acid (B+Cy), BFA base mix + A1 to A4 (B+A1-A4), BFA base mix + A5 to A10 (B+A5-A10), and BFA base mix + humic acid (B+H). It mainly targeted the general DBP formation (combined chlorine, THMs, HAAs, and nitrosmaines) from groups of organic compounds. The other set of experiments was conducted on simulated swimming pool water with individual PCP additives and humic acid to further investigate the influence of individual PCP additives on DBP formation.

4.3.3.1 Results of DBP formation from simulated swimming pool

water spiked with subgroups of PCP additives in 5 days

Results with respect to DBP formation from the reactions between subgroups of organic compounds and free chlorine are shown in Table 4.3-11. It should be noted that

87 by the end of the 5day incubation, only 0.1 mg/L free chlorine was left.

Table 4.3-11 Results of DBP formation in simulated swimming pool water spiked with subgroups

of PCP additives (5 day reaction)

Combined THMs HAA9 MCAA DCAA TCAA NDMA SampleID Chlorine (mg/L) (µg/L) (µg/L) (µg/L) (µg/L) (µg/L) (ng/L) Control

As shown in Figure 4.3-11, there is a significant formation of combined chlorine in simulated swimming pool water compared with the control (MilliQ water) due to the addition of organic compounds. Samples with subgroups of PCP additives produced more combined chlorine compared with samples of BFA base mix, BFA base mix + cyanuric acid (B+Cy), and BFA base mix + humic acid (B+H). Although it should be noted that addition of PCP additives in groups may have reciprocal effects on each other and consequently may influence the quantity of combined chlorine formations, these results are consistent with the results in Section 4.3.1 and Section 4.3.2 in thatA1 to A4 and A5 to A10 had similar measurable combined chlorine residuals.

3.0

2.5

2.0

1.5

1.0 Concentration(mg/L)

0.5

Figure 4.3-11 Concentration of combined chlorine formed in simulated swimming pool water

spiked with subgroups of PCP additives within 5 days

Results of THMs and HAAs are shown in Figures 4.3-12 and 4.3-13. Compared with the control, all subgroups of organic compounds showed a significant potential to form THMs and HAAs. For THM formation, as shown in Figure 4.3-12, the group of PCP additives A1 to A4 and humic acid increased the concentration of THMs compared with the BFA base mix alone, whereas cyanuric acid and the group of PCP additives A5 to A10 had similar formation of THMs to the base mix alone. These results indicate that base mix, subgroup of PCP additives A1 to A4 and huimic acid contain THM precursors.

In terms of HAA9, B, B+Cy, B+A1-A4 and B+H had comparable formation of HAA9, but HAA9 for the group of PCP additives A5 to A10 was significantly smaller than other groups (Figure 4.3-13). It shows that base mix and humic acid contain HAA precursor, and components in subgroup of PCP additives A5 to A10 mix appeared to inhibit HAA formation from precursor in base mix.

160

g/L) 120 μ

40 TTHM concentration ( concentration TTHM

0 Control B B+Cy B+A1-A4 B+A5-A10 B+H

Figure 4.3-12 Concentration of TTHM following 5 days of reaction of simulated swimming pool

water spiked with subgroups of PCP additives

MCAA DCAA TCAA HAA9 250

200

g/L) μ 150

100

50 Concentration ( Concentration

0 Control B B+Cy B+A1- HAA9 B+A5- B+H TCAA

A4 A10 DCAA MCAA

Figure 4.3-13 Concentration of HAA9 following 5 days of reaction of simulated swimming pool

water spiked with subgroups of PCP additives

In this set of experiments, only NDMA was detected rather than any other nitrosamines. As shown in Figure 4.3-14, the subgroup of A5 to A10 had the highest formation potential of NDMA (~28 ng/L), followed by the subgroup of A1 to A4 (~12 ng/L

NDMA), and cyanuric acid and humic acids only produced less than 5 ng/L NDMA. BFA base mix shows no capability of NDMA formation potential, its concentration of NDMA was below MDL.

10 Concentration (ng/L) Concentration

Figure 4.3-14 Concentration of NDMA following 5 days of reaction of simulated swimming pool

water spiked with subgroups of PCP additives

4.3.3.2 Results of DBP formation from simulated swimming pool

water spiked with individual PCP additives in 48 hours and

120 hours

In order to further investigate the effects of PCP compounds on DBP formation, PCP additives were individually spiked into simulated swimming pool water made of BFA base mix compounds. Formation of combined chlorine, THMs, HAAs, and nitrosamines were measured at 48 hours and 120 hours. The two reaction times were employed to see if there was a significant kinetic effect, and to see if the duration of subsequent experiment could be shortened to 2 days (48 hours) from 5 days (120 hours). The same initial concentration of 50 mg/L free chlorine was applied. Simulated swimming pool water was made of BFA base mix compounds at the same

91 concentrations as in Section 4.3.3.1. The concentration of each PCP additive compound was 1 mg/L. Samples were incubated in 1 liter amber bottles at room temperature.

Figure 4.3-15 presents free chlorine residual at 48 hours and 120 hours, and there was only 0.1 mg/L free chlorine detected at 120 hours. As shown in Figure 4.3-16 and Table 4.3-12, all PCP additives have similar formation potential of combined chlorine at each reaction time. Although the concentration of combined chlorine decreased as the reaction time increased from 24 hours to 120 hours, as expected, there was still 1.5~1.8 mg/L combined chlorine detected at 120 hours. Results of combined and free chlorine residual, especially at 120 hours indicate that it is possible for combined chlorine to be consumed or degraded when free chlorine was absent. In addition, in control sample with MilliQ water alone (not shown), free chlorine did not exhibit any decay or consumption and its concentration was maintained constant at 50 mg/L. Therefore, the degradation or consumption of chlorine should be attributed to the reactions between organic matter and chlorine.

48-hour free chlorine 120-hour free chlorine 2.0

1.6

1.2

0.8

Concentration (mg/L) Concentration 0.4

0.0 BA1 BA2 BA3 BA4 BA5 BA6 BA7 BA8 BA9 BA10 BH

Figure 4.3-15 Concentration of free chlorine in simulated swimming pool water spiked with PCP

additives individually at 48 hours and 120 hours

48-hour combined chlorine 120-hour combined chlorine 3.0

2.5

2.0

1.5

1.0

Concentration (mg/L) Concentration 0.5

0.0 BA1 BA2 BA3 BA4 BA5 BA6 BA7 BA8 BA9 BA10 BH

Figure 4.3-16 Concentration of combined chlorine individually at 48 hours and 120 hours

Table 4.3-12 Results of free and combined chlorine in simulated swimming pool water spiked with

PCP additive

Sample 48 hour free 120 hour free 48 hour combined 120 hour combined ID chlorine (mg/L) chlorine (mg/L) chlorine (mg/L) chlorine (mg/L) BA1 1.40 0.03 2.17 1.76 BA2 1.40 0.07 2.20 1.56 BA3 1.00 0.01 1.83 1.47 BA4 1.03 0.02 2.63 1.63 BA5 1.60 0.05 2.43 1.45 BA6 1.50 0.04 2.07 1.61 BA7 1.37 0.03 2.40 1.44 BA8 1.27 0.04 2.70 1.88 BA9 1.37 0.11 2.33 1.47 BA10 1.40 0.04 2.20 1.44 BH 1.33 0.03 2.17 1.40

Despite having similar free and combined chlorine concentrations, the individual PCP additives showed different formation potentials in terms of their formation of other DBPs, as shown in Table 4.3-13.

Table 4.3-13 Results of THMs, HAAs and nitrosamines in simulated swimming pool water spiked with PCP additive 48 hour 120 hour 48 hour 48 hour 48 hour 120 hour 120 hour 120 hour 48 hour 48 hour 120 hour 120 hour Sample THMs THMs HAA DCAA TCAA HAA DCAA TCAA NDMA NDBA NDMA NDBA ID 9 9 (µg/L) (µg/L) (µg/L) (µg/L) (µg/L) (µg/L) (µg/L) (µg/L) (ng/L) (ng/L) (ng/L) (ng/L) BA1 167 173 132 119 13 215 184 32 79 12 77 11 BA2 179 160 121 106 15 195 164 31 122 23 80 13 BA3 123 159 132 112 21 374 300 78 17 15 6.3 6.9 BA4 107 184 141 124 17 220 188 32 137 30 14 5.7 BA5 138 177 150 133 17 234 201 32 72 35 11 9.9 BA6 288 352 153 132 20 225 189 36 40 17 13 6.2 BA7 150 170 168 149 19 228 195 32 40 15 14 6.9 BA8 220 216 166 145 21 242 207 35 86 56 61 13 BA9 168 168 158 127 31 190 152 39 89 30 12 5.5 BA10 151 173 171 147 24 229 195 34 58 26 7.0 5.4 BH 196 212 186 145 40 253 194 59 43 22 5.6 3.9

As shown in Figure 4.3-17, PCP additive A6 (cetyltrimethylammonium chloride) produced the highest formation potential of THMs, which was almost 2 times as high as other PCP additives. Molecular structure of A6 in Figure 4.3-18 shows it has a long hydrocarbon chain with quaternary amino nitrogen at the end. Compared with other PCP additives, this unique structure could be one of reasons for its high formation potential of THMs. Even though PCP compound A9 (behentrimonium chloride) has a similar molecular structure, its hydrocarbon chain was longer, and thus it is not as water soluble as A6. Since the solubility of the compound will affect its reaction kinetics with chorine in the aqueous solution, it can explain why A6 had a higher formation of THMs than A9. In addition, as shown in Figure 4.3-17, THMs only had a slight increase in formation from 48 hours to 120 hours (0 to 20 %) indicating that THM formation was mainly completed within 48 hours and that further reactions would be fairly slow.

48-hour THMs 120-hour THMs

400

300

200

100 Concentration (µg/L) Concentration

0 BA1 BA2 BA3 BA4 BA5 BA6 BA7 BA8 BA9 BA10 BH

Figure 4.3-17 Concentration of THMs in simulated swimming pool water spiked with PCP

additives individually at 48 hours and 120 hours

Figure 4.3-18 Molecular structure of PCP additive A6 cetyltrimethylammonium chloride

Compared with the results of THM formation, HAA formation from individual PCP additives showed a different pattern. As shown in Figure 4.3-19, PCP additives A3 (nitrilotriacetic acid) produced the highest concentration of HAAs. Its molecular structure, as shown in Figure 4.3-20, includes three acetic acid groups, and thus makes A3 most readily reactive with chlorine to form HAAs. The significant increment of HAA formation from 48 hours to 120 hours (20 to 180%) indicates that HAA has a relatively slow formation kinetics from these PCP additives, and it tends to form continually even in a longer reaction time.

48-hourHAA9 120-hour HAA9 450

360

270

180

Concentration (µg/L) Concentration 90

0 BA1 BA2 BA3 BA4 BA5 BA6 BA7 BA8 BA9 BA10 BH

Figure 4.3-19 Concentration of HAA9 in simulated swimming pool water spiked with PCP

additives individually at 48 hours and 120 hours

Figure 4.3-20 Molecular structure of PCP additive A3 nitrilotriacetic acid

The formation of both NDMA and NDBA was observed. PCP additives A1, A2, A4, A5,

A8, A9, and A10 had relatively higher formation of NDMA ranging from 60 ng/L to 140 ng/L at 48 hours compared with other additives (Figure 4.3-21), whereas PCP additives A2, A4, A5, A8, A9, A10 and humic acid produced high concentration of NDBA ranging from 20 ng/L to 55 ng/L at 48 hours (Figure 4.3-22). However, at 120 hours, only A1 (diethanolamine) , A2 (Padimate O), and A8 (cocamidopropyl betaine) produced NDMA of approximately 80ng/L, 80 ng/L, and 60 ng/L, respectively, and only A1, A2, A5, A8 produced NDBA of approximately 10 ng/L.

Given there was no significant formation of nitrosamines from BFA base mix in Section 4.3.3.1, the formation of NDMA and NDBA indicates that some PCP additives can potentially be precursors of nitrosamines at relatively high concentrations when reacting with relatively high concentration of free chlorine (50 mg/L). In addition, as shown in Section 4.3.3.1, only 10 ng/L and 26 ng/L of NDMA was formed from BFA base mix + A1 to A4 and BFA base mix +A5 to A10, respectively. This was lower than the sum of NDMA formed from individual PCP additives in BFA base mix. Again, this indicates that PCP additives may have a reciprocal influence on each other during DBP formation.

48-hour NDMA 120-hour NDMA 160 140

120 100

80 60

Concentration (ng/L) Concentration 40

20 0 BA1 BA2 BA3 BA4 BA5 BA6 BA7 BA8 BA9 BA10 BH

Figure 4.3-21 Concentration of NDMA in simulated swimming pool water spiked with PCP

additives individually at 48 hours and 120 hours

In addition, as shown in Figures 4.3-21 and 4.3-22, the concentrations of nitrosamines generally decreased from 48 hours to 120 hours. This was unexpected and needs to be further investigated.

48-hour NDBA 120-hour NDBA 60

20 Concentration (ng/L) Concentration 10

0 BA1 BA2 BA3 BA4 BA5 BA6 BA7 BA8 BA9 BA10 BH

Figure 4.3-22 Concentration of NDBA in simulated swimming pool water spiked with PCP

additives individually at 48 hours and 120 hours

4.3.4 DBP formation potential of BFA compounds, PCP additives,

cyanuric acid and humic acid under chloramination conditions

Although swimming pools operate under superchlorination conditions (high chlorine doses to exceed breakpoint and result in free chlorine residuals), occasional releases of ammonia may result in temporary formation of combined inorganic chlorine (monochloramine, dichloramine, nitrogen trichloride) that would react with BFA or PCP components to form byproducts. Since this is not likely a major occurrence in swimming pools, it will not be exhaustively studied in this thesis. However, the results may prove to be useful when considering possible follow up or parallel studies on drinking water, for which monochloramine is a commonly used secondary disinfectant

In order to investigate DBP formation potential of BFA base mix compounds and PCP, BFA base mix compounds, PCP additives, cyanuric acid and humic acid were incubated

98 with 2.9 mg/L monochloramine in 1 liter amber bottles for 24 hours at room temperature. Concentration of BFA compounds used in this section was the same as that mentioned in previous sections. Concentration of PCP additives and humic acid was 1 mg/L. Concentration of cyanuric acid was 30 mg/L. DBPs formed are compared with those in Section 4.3.3.

4.3.4.1 DBP formation potential of BFA base mix compounds,

stabilizer (cyanuric acid), and humic acid under

chloramination

In this section, formation of combined chlorine (not including NH2Cl), THMs, HAAs, and nitrosamines were measured. As shown in Figures 4.3-23 and 4.3-24, BFA compound #3 (histidine) showed 0.8 mg/L monochloramine and total chlorine consumption. This may imply that addition of histidine can accelerate degradation of monochloramine by some unknown mechanisms. As shown in Figure 4.3-25, only BFA compound #6 (citric acid) produced a significant concentration of combined chlorine (about 1.2 mg/L relative to about 0.6 mg/L) under the condition of chloramination. This indicates that citric acid can convert monochloramine into combined chlorine and it might be due to its special molecular structure of having three carboxyl groups in the molecule. No other BFA compounds showed significant consumption of chlorine.

As to cyanuric acid, it is interesting to find that its monochoramine residual after 24 hours was only 0.2 mg/L, but it had as high as 2.8 mg/L free chlorine detected after 24 hours which accounted for more than 95% of total chlorine. Therefore, it is assumed that cyanuric acid could capture –Cl group from monochloramine (weaker bond than chlorocyanuric acid) but it could not hold it as combined chlorine (weaker bond than chloro-DPD) during the measurement by DPD, and thus it was labeled as free chlorine in Figure 4.3-25. Otherwise, the behavior of cyanuric acid under chloramination is consistent with previous results in Section 4.3.2 during the free chlorine breakpoint test.

2.5

2.0

1.5

1.0

Concentration (mg/L) Concentration 0.5

0.0 MQ-2 MQ-3 MQ-4 MQ-5 MQ-6 MQ-7 MQ-Cy MQ-H MQ-Ctl

Figure 4.3-23 Concentration of monochloramine in samples of MilliQ water spiked with BFA

compounds (#2 to #7), cyanuric acid (30 mg/L), and humic acid (1 mg/L ) while initial

monochloramine was 2.9 mg/L

4.0

3.0

2.0

1.0 Concentration (mg/L) Concentration

0.0 MQ-2 MQ-3 MQ-4 MQ-5 MQ-6 MQ-7 MQ-Cy MQ-H MQ-Ctl

Figure 4.3-24 Concentration of total chlorine in samples of MilliQ water spiked with BFA compounds, cyanuric acid (30 mg/L), and humic acid (1 mg/L ) while initial monochloramine was

2.9 mg/L

100

3.0 Measured as free chlorine

2.5

2.0

1.5

1.0

Concentration (mg/L) Concentration 0.5

0.0 MQ-2 MQ-3 MQ-4 MQ-5 MQ-6 MQ-7 MQ-Cy MQ-H MQ-Ctl

Figure 4.3-25 Concentration of combined chlorine in samples of MilliQ water spiked with BFA compounds, cyanuric acid (30 mg/L), and humic acid (1 mg/L ) while initial monochloramine was

2.9 mg/L (sample of cyanuric acid was measured as free chlorine)

There was no detectable formation of THMs and HAAs from BFA base mix compounds, cynanuric acid or humic acid under chloramination. However, as shown in Figure 4.3-26, NDEA, NDMA and NDBA were detected among these samples. Sample with humic acid and cyanuric acid produced 20 ng/L and 15 ng/L NDMA, respectively. Sample with BFA compounds #4 to #7 produced approximately 9 ng/L NDMA, whereas control sample only exhibited 3.4 ng/L NDMA formations. This indicates that humic acid, cyanuric acid and BFA compounds #4 to #7 could be potential NDMA precursors under chloramination condition. In addition, BFA compounds #2 (urea), #4 (hippuric acid) and cyanuric acid produced 20 ng/L, 23 ng/L and 19 ng/L NDBA, respectively. Compared with 15 ng/L of DBA formation in control sample, BFA compounds #2, #4 and cyanuric acid showed potential of NDBA formation. None of the BFA compound, cyanuric acid or humic acid showed NDEA formation potential under chloramination condition. Results indicate that humic acid, cyanuric acid, and BFA compounds #2 (urea), #4 (hippuric acid) can be potential nitrosamine precursors under chloramination.

101

NDEA NDMA NDBA

5 Concentration (ng/L) Concentration

MQ-2

MQ-3

MQ-4

MQ-5

MQ-6

MQ-7

NDBA

NDMA

MQ-H

MQ-Cy NDEA MQ-Ctl

Figure 4.3-26 Concentration of NDEA, NDMA, and NDBA in samples of MilliQ water spiked with

BFA compounds, cyanuric acid (30 mg/L), and humic acid (1 mg/L ) while initial monochloramine

was 2.9 mg/L

4.3.4.2 DBP formation potential of PCP additives under

chloramination

Figures 4.3-27 to 4.3-29 are the total chlorine, monochloramine and combined chlorine residuals (not including NH2Cl) for water spiked with PCP additives. Since no significant concentration of free chlorine is present in a monochloramine system, its concentration is not shown here. There was no significant decrease of total chlorine residuals for all of PCP additives; they were constantly maintained at 2.9 mg/L. However, final concentrations of monochloramine and combined chlorine were different among these PCP additives. PCP additives A1 (diethanolamine), A2 (Padimate O) and A9 (behentrimonium chloride) showed the lowest concentrations of monochloramine residual, which were coincident with the highest concentrations of combined chlorine for these additives.

102

4.0

3.0

2.0

1.0 Concentration (mg/L) Concentration

0.0 MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 Ctl

Figure 4.3-27 Concentration of total chlorine in samples of MilliQ water spiked with 1 mg/L of

PCP additives while initial monochloramine was 2.9 mg/L

3.0

2.5

2.0

1.5

1.0

Concentration (mg/L) Concentration 0.5

0.0 MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 Ctl

Figure 4.3-28 Concentration of monochloramine in samples of MilliQ water spiked with 1 mg/L of

PCP additive while initial monochloramine was 2.9 mg/L

103

1.6

1.2

0.8

0.4 Concentration (mg/L) Concentration

0.0 MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- MQ- A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 Ctl

Figure 4.3-29 Concentration of calculated combined chlorine in samples of MilliQ water spiked

with 1 mg/L of PCP additive while initial monochloramine was 2.9 mg/L

Molecular structures of A1 and A2 are shown in Figures 4.3-30 and 4.3-31, respectively. There is an amino group in both A1 and A2, and the hydrogen in the amino group would be readily substituted by –Cl from monochloramine, therefore leading to the dominant formation of combined chlorine. Approximately 1.2 mg/L of combined chlorine detected further confirmed that the reaction of A1 and A2 with monochloraine proceeded at a molar ratio of approximately 1:1. On the other hand, no suitable functional group was present in PCP additive A9, as shown in Figure 4.3-32, and it indicates that combined chlorine could be formed from the impurity in A9 which was approximately 20 wt. % of A9 (Materials and Methods).

Figure 4.3-30Molecular structure of PCP additive A1 diethanolamine

104

Figure 4.3-31Molecular structure of PCP additive A2 Padimate O (NPABAO)

Figure 4.3-32Molecular structure of A9 behentrimonium chloride

There was no significant formation of either THMs or HAAs (under detection limit) when PCP additives were incubated with monochloramine for 24 hours at room temperature, whereas results in Section 4.3.3 had shown high formation potential of THMs and HAAs under condition of chlorination. This is expected and well agrees with the results in historic DBP literatures.

However, nitrosamines, including NDMA, NDEA and NDBA were detected in the samples. As shown in Figure 4.3-33, compared with control sample, the most significant formation of NDMA (45 ng/L) was from PCP additive A8 (cocamidopropyl betaine) followed by A9 (behentrimonium chloride) and A10 (tetramethylammonium chloride) in which approximately 10 ng/L NDMA formed. In addition, there was approximately 27 ng/L to 32 ng/L NDBA formation in samples spiked with PCP additives A2 (Padimate O), A3 (nitrilotriacetic acid), A5 (tetrabutylammonium chloride), and A8 (cocamidopropyl betaine). Although some of the PCP additives A8, A9 and A10 showed NDMA formation potential, results did not show widely significant formation of nitrosamines from PCP additives even with monochloramine. It further justified the selection of free chlorine for this study.

105

NDEA NDMA NDBA

15 Concentration (ng/L) Concentration

MQ-A1

MQ-A2

MQ-A3

MQ-A4

MQ-A5

MQ-A6

NDBA

MQ-A7

MQ-A8

NDMA

MQ-A9

NDEA

MQ-Ctl MQ-A10

Figure 4.3-33 NDEA, NDMA, and NDBA in MilliQ water spiked with BFA compounds, 30 mg/L

cyanuric acid, and 1 mg/L humic acid while initial monochloramine of 2.9 mg/L

4.3.5 Summary

Simulated swimming pool water containing BFA compounds was used as a fundamental matrix to investigate the influence of PCP additives on DBP formation. Four different types of DBPs, including combined chlorine, trihalomethanes (THMs), haloacetic acids (HAAs) and nitrosamines were measured.

Theoretical TOC values were calculated to determine the concentration for BFA base mix compounds and PCP additives used for this study. Results showed that the applied concentrations matched TOC measurements of real swimming pool water samples very well.

Free chlorine demand from BFA base mix alone was higher than that from the base mix spiked with subgroups of PCP additives and cyanuric acid. It is possible that free chlorine demand was reduced due to the formation of unstable combined chlorine, especially at the beginning of the incubation period when there was a high concentration of both free chlorine and combined chlorine. Subsequent DBP results

106 showed that HAA formation was decreased due to the formation of more combined chlorine and THM formation was increased possibly from potential THM precursors in PCP additives. In addition, cyanuric acid neither showed any potential of DBP formation nor any significant influence on DBP formation.

More experiments were conducted on simulated swimming pool water with individual PCP additives, cyanuric acid and humic acid. Results showed that BFAs, PCPs and humic acid exhibited higher formation potential of THMs and HAAs under condition of chlorination than that under condition of chloramination in which THMs and HAAs were under detection limit. On the other hand, although the formation of nitrosamines was favorable with monochloramine, most of the PCP additives and BFA compounds in this study did not show very high nitrosamine formation potential regardless of chlorination or chloramination. Nonetheless, the results of the DBP formation test warranted the application of chlorination rather than chloramination in subsequent tests.

Free chlorine demand and formation of combined chlorine from individual BFAs and PCPs were measured to help understand and choose an initial concentration of free chlorine for subsequent studies (Chapter 5).Results also indicate that most of the free chlorine demand and formation of combined chlorine were completed within 1.5 hours (as shown in Section 4.3.1). In addition, DBP formation tests did not show significant DBP formation with reaction time extending from 48 hours to 120 hours (as shown in Section 4.3.3.2). Therefore, combined with historic literature showing at least 80% of DBP could be formed in 24 hours compared with in 72 hours (known as optimum time for THM formation in portable water) (Summers et al., 1996; Ram et al., 1986; Eichelsdorfer and Jandik, 1984), reaction time of 24 hours would be applied in subsequent test (Chapter 5).

107

Chapter 5 Effects of additives on DBP formation in pool water

Effects of additives on DBP formation in pool water

Experiments described in this chapter investigated the effects on Disinfection Byproduct (DBP) formation from Body Fluid Analogue (BFA) compounds, Personal Care Products (PCP), pool stabilizer (cyanuric acid), and humic acid in swimming pool water. Previous measurements of swimming pool water in Chapter 4 showed that higher organic inputs corresponded to high DBP formation in swimming pool water. They also showed that effects from BFA compounds and PCP additives included promoting or suppressing DBP formation, acting as potential DBP precursors or competing with DBP precursors for reaction with chlorine. As well, the outdoor hot tub (Out3) had the highest DBP formation from the highest bather load. Therefore, it was chosen as the initial experimental water matrix to investigate the DBP formation with influence of pool water matrices. Follow-up experiments were performed with water from one of the indoor pools (In2). BFA compounds and PCP additives were spiked into swimming pool water for 24 hours and DBPs including combined chlorine, trihalomethanes (THMs), haloacetic acids (HAAs), and nitrosamines were analyzed.

5.1 Influence of BFA base mix compounds, PCP additives, pool stabilizer and humic acid on DBP formation in outdoor swimming pools (Part III)

Outdoor swimming pools are often running during summer time in public community center or private household in Ontario. In comparison with indoor swimming pools, they are more vulnerable to influences from the environment, such as direct sun

108 irradiation, wind, and rain, and could be more loaded by contaminant input, such as sweat from bathers, dust from leaves, and rain (precipitation). Environmental influences can cause faster disinfectant dissipation, and contaminant input may also cause more disinfectant consumption as well as more formation of disinfection byproducts.

In this section, the results for experiments using water from an outdoor hot tub (Out3) will be described first as it is a particularly interesting water matrix, given that it had the highest TOC value and DBP concentrations compared with other outdoor pools. These results show a minimal incremental effect of BFA compounds and PCP additives on DBP formation under these more extreme conditions, such as high TOC values. When effects were observed, the Significance of the influence from BFA compounds and PCP additives on DBP formation was t-tested and results are shown in Appendix 9.4.

5.1.1 Influence of BFA compounds on DBP formation in outdoor

swimming pool (Out3) water matrix

―BFA base mix‖ included seven different BFA compounds #1 (ammonium chloride), #2 (urea), #3 (L-histidine), #4 (hippuric acid), #5 (uric acid), #6 (citric acid), and #7 (creatinine). Experiments of this part were conducted to investigate the DBP potential of BFA base mix compounds as possible precursors and/or their effects of promotion/suppression during the formation of DBPs. BFA compound #1(ammonium chloride) was not spiked into outdoor pool water since it will exceed breakpoint and will be lost as N2 when reacting with free chlorine in swimming pool water where there is normally a high free chlorine residual (typically higher than 1.5 mg/L).

The other six BFA compounds #2 to #7 were spiked into outdoor swimming pool water to examine their effects on DBP formation. Concentrations of BFA compounds are shown in Table 5.1-1, which were selected to produce TOC values that were similar to those in real swimming pool water samples. Water samples were incubated in 1 liter amber bottles for 24 hours at room temperature. Incubation period of 24 hours ensured

109 the completion of most of the DBP formation based on the results from Section 4.3.

Table 5.1-1 Concentrations of BFAs used for Out3 pool water experiments Ingredient ID Concentration (mg/L) Ammonium chloride BFA #1 2 Urea BFA #2 14.8 Histidine BFA #3 1.21 Hippuric acid BFA #4 1.71 Uric acid BFA #5 0.49 Citric acid BFA #6 0.64 Creatinine BFA #7 1.8

5.1.1.1 Influence on combined chlorine formation

Free chlorine and total chlorine were measured using a Hach kit after reaction times of 1.5 hours and 24 hours. The measurements at 1.5 hours ensured that free chlorine residual at 1.5 hours was at least 1.5 mg/L, which would be enough to satisfy the free chlorine demand throughout the total 24 hours incubation time. Formation of more stable combined chlorine (organic choramine compounds) was calculated based on measurements of free and total chlorine following the 24 hours reaction period.

For samples spiked with BFA compound #7 (creatinine), as shown in Figure 5.1-1, the decrease of free chlorine was more significant compared to control samples, and it was primarily because of the formation of combined chlorine. Although free chlorine in the samples spiked with BFA compound #3 (histidine) was significantly decreased as well, it did not correspond to a formation of combined chlorine, which is consistent with the results from the test with monochloramine in Section 4.3.4 where monochloramine and total chlorine were equally consumed in sample with BFA compounds #3 (histidine). On the other hand, as shown in Table 5.1-2 and Figure 5.1-2, BFA compound #7 (creatinine) produced the highest concentration of combined chlorine among all of the BFA compound spiked samples and control samples. Results are consistent with those obtained from the breakpoint test in Figure 4.3-8 in Section 4.3.2 where BFA compound #7 (creatinine) produced noticeable combined chlorine. Other BFA

110 compounds did not show significant formation of combined chlorine when compared with the control.

Table 5.1-2 Concentration of free and combined chlorine in outdoor swimming pool (Out3) spiked

with BFA compounds #2 to #7 individually

1.5 hours 24 hours 1.5 hours 24 hours Sample free chlorine free chlorine Combined Combined ID (mg/L) (mg/L) chlorine (mg/L) chlorine (mg/L) (Out3)-2 5.25 3.10 1.43 1.28 (Out3)-3 4.03 2.18 1.30 1.37 (Out3)-4 5.55 3.73 1.23 1.45 (Out3)-5 5.07 3.43 1.52 1.23 (Out3)-6 5.12 3.82 1.45 1.37 (Out3)-7 4.43 2.63 2.28 2.42 (Out3)-Ctl 5.18 3.27 1.63 1.22 (Out3-Ctl) means unspiked swimming pool (Out3) water.

1.5 hours free chlorine 24 hours free chlorine

6.0

4.8

3.6

2.4

Concentration (mg/L) Concentration 1.2

0.0 (Out3)-2 (Out3)-3 (Out3)-4 (Out3)-5 (Out3)-6 (Out3)-7 (Out3)-Ctl

Figure 5.1-1 Concentration of free chlorine in outdoor swimming pool (Out3) water spiked with

BFA compounds #2 to #7 individually

111

1.5 hr combined chlorine 24 hr combined chlorine 3.0

2.5

2.0

1.5

1.0 Concentration (mg/L) Concentration 0.5

0.0 (Out3)-2 (Out3)-3 (Out3)-4 (Out3)-5 (Out3)-6 (Out3)-7 (Out3)-Ctl

Figure 5.1-2 Concentration of combined chlorine in outdoor swimming pool (Out3) water spiked

with BFA compounds #2 to #7 individually

5.1.1.2 Influence on THM formation

THMs were measured after a 24 hour incubation period to examine the influence of BFA compounds on THMs formation in outdoor swimming pool water. Results are shown in Table 5.1-3 and Figure 5.1-3. Compared with control sample of outdoor swimming pool (Out3) water alone, no significant formation of THMs was observed after the addition of BFA compounds #2 to #7.

Even though previous results in Section 4.3.3.1 showed that approximately 100 µg /L THMs were formed from the BFA base mix compound in the simulated pool water, reaction conditions in those tests were that free chlorine concentration was as high as 50 mg/L and reaction time was set as 5 days. Therefore, it is not too surprising to observe that THMs did not form significantly when BFA compounds were individually spiked into outdoor swimming pool water (Out3) in which approximately 800 µg/L initial THMs were already present.

112

Table 5.1-3Concentration of THMs in outdoor swimming pool (Out3) spiked with BFA compounds

#2 to #7 individually

Sample ID THMs (µg/L) (Out3)-2 788 (Out3)-3 769 (Out3)-4 772 (Out3)-5 742 (Out3)-6 832 (Out3)-7 792 (Out3)-Ctl 769 (Out3-Ctl) means unspiked swimming pool (Out3) water.

1000

800

600

400

200 TTHM Concentration (µg/L) Concentration TTHM

0 (Out3)-2 (Out3)-3 (Out3)-4 (Out3)-5 (Out3)-6 (Out3)-7 (Out3)-Ctl

Figure 5.1-3 Concentration of THMs in outdoor swimming pool (Out3) water spiked with BFA

compounds #2 to #7 individually

5.1.1.3 Influence on HAA formation

Concentrations of HAA9 were measured for the purpose of investigating the effects of addition of BFA compounds on HAA formation in the outdoor swimming pool water (Out3). It should be noted that only monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), and trichloroacetic acid (TCAA) were reported in this section due to the low concentrations of other HAA species.

113

As shown in Table 5.1-4 and Figure 5.1-4, compared with control sample, BFA compounds #6 (citric acid) and #7 (creatinine) produced high concentration of HAA9 (2407 µg/L and 2345 µg/L, respectively) while BFA compounds #2 (urea), #4 (hippuric acid) and #5 (uric acid) produced relatively low concentration of HAA9 ranging from 2077 to 2142 µg/L. The molecular structure of BFA compound #6 (citric acid) is shown in Figure 5.1-5, and it contains three carboxyl groups. With high concentration of free chlorine, there is a high possibility that citric acid could be easily oxidized and halogenated to form HAA (Bond et al., 2009). In terms of BFA compound #7

(creatinine), its higher formation potential of HAA9 could be because it produced relatively higher concentration of combined chlorine which could provide reactive –Cl group to HAA9 precursors and consequently increase the formation of HAA9. However, further investigation is needed regarding how combined chlorine releases –Cl group and its role on HAA formation. On the contrary, lower HAA formation with addition of BFA compounds #2 (urea), #3 (histidine), #4 (hippuric acid) and #5 (uric acid) than in samples with BFA compounds #6 and #7 indicates that HAA formation can be suppressed by the addition of BFA compounds, except there is a more important promoting effect, such as potential precursor of BFA compound #6 and more reactive – Cl from BFA compound #7. In addition, DCAA formation was always dominant over MCAA and TCAA formation in all the samples, which should be related to the type of HAA precursors in Out3 pool water given that TCAA should be dominant HAA species over MCAA and DCAA when there is a high free chlorine concentration (Hwang et al. 2001.

114

Table 5.1-4 Concentration of HAA9 and main species in outdoor swimming pool (Out3) spiked

with BFA compounds #2 to #7 individually

Sample ID HAA9 (µg/L) MCAA (µg/L) DCAA (µg/L) TCAA (µg/L) (Out3)-2 2142 244 1107 791 (Out3)-3 2215 258 1150 806 (Out3)-4 2077 233 1086 758 (Out3)-5 2105 238 1107 760 (Out3)-6 2407 277 1256 871 (Out3)-7 2345 274 1229 843 (Out3)-Ctl 2248 256 1193 799 (Out3-Ctl) means unspiked swimming pool (Out3) water.

MCAA DCAA TCAA HAA9

2500

2000

1500

1000

500 Concentration (µg/L) Concentration

HAA9

TCAA

(Out3)-2

DCAA

(Out3)-3

(Out3)-4

(Out3)-5

MCAA

(Out3)-6 (Out3)-7

(Out3)-Ctl

Figure 5.1-4 MCAA, DCAA, TCAA and HAA9 in outdoor swimming pool (Out3) water spiked

with BFA compounds #2 to #7 individually

Figure 5.1-5 Molecular structure of BFA compound #6 citric acid

115

5.1.1.4 Influence on nitrosamine formation

Nitrosamines were measured for the examination of influence from BFA compounds #2 to #7 on nitrosamine formation in outdoor swimming pool (Out 3) water matrix. In this study, only NDEA and NDBA were detectable. As shown in Table 5.1-5 and Figure 5.1-6, in comparison with the control sample, there was no significant difference in the formation of NDEA from BFA compounds #2 to #7, NDBA formation was decreased for BFA compounds #2 (urea), #3 (histidine), #5 (uric acid), #6 (citric acid), and #7 (creatinine within 24-hour incubation period. The decrease of NDBA formation indicates that original NDBA formation potential in the outdoor pool bulk water (Out3) was influenced by the addition of these BFA compounds. However, it is uncertain about the underlying reasons, and it might be because the addition of these BFA compounds had a suppressing effect on the reactivity of NDBA precursors with chlorine or led to the transformation of NDBA precursors to other products.

Table 5.1-5 Concentration of nitrosamines (NDEA/NDBA) in outdoor swimming pool (Out3)

spiked with BFA compounds #2 to #7 individually Sample ID NDEA (ng/L) NDBA (ng/L) (Out3)-2 61 97 (Out3)-3 64 103 (Out3)-4 67 157 (Out3)-5 58 114 (Out3)-6 59 121 (Out3)-7 64 119 (Out3)-Ctl 57 168 (Out3-Ctl) means unspiked swimming pool (Out3) water.

116

NDEA NDBA 200

160

120

Concentration (ng/L) Concentration 0

(Out3)-2

(Out3)-3

(Out3)-4

NDBA

(Out3)-5

(Out3)-6

NDEA

(Out3)-7 (Out3)-Ctl

Figure 5.1-6 NDEA and NDBA in outdoor swimming pool (Out3) water spiked with BFA

compounds #2 to #7 individually

5.1.2 Influence of PCP additives on DBP formation in outdoor

swimming pool (Out3) water matrix

Additives in Personal Care Products (PCPs), such as body lotion, cosmetics and sunscreens, can be introduced into swimming pools by swimmers. For example in outdoor swimming pools, swimmers tend to use large amount of sunscreens. This part of experiments examined the influence of PCP additives on DBP formation in outdoor swimming pool.

In this study, selected PCP additives include secondary amine (PCP additive A1), tertiary amines (PCP additives A2 to A4) and quaternary amines (PCP additives A5 to A10). In detail, they are A1 (Diethanolamine), A2 (Padimate O), A3 (Nitrilotriacetic acid), A4 (Triehanolamine), A5 (Tetrabutylammonium chloride), A6 (Cetyltrimethylammonium chloride), A7 (Choline chloride), A8 (Cocamidopropyl betaine), A9 (Behentrimonium chloride), and A10 (Tetramethylammonium chloride).

117

Experiments were conducted to investigate the possible influence of PCP additives on the formation of DBPs. It is possible that these PCP additives would act as DBP precursors and promote DBP formation. They may also compete with existing DBP precursors in outdoor swimming pool for free chlorine and consequently suppress DBP formation. PCP additives were spiked into the outdoor swimming pool water (Out3) at concentration of 1 mg/L individually. Samples were incubated in 1 liter amber bottles for 24 hours before sampling for DBPs. Reaction temperature was set at room temperature which is similar to outdoor swimming pool operating temperature.

5.1.2.1 Influence on combined chlorine formation

Free chlorine and total chlorine were both measured at 1.5 hours and 24 hours. Combined chlorine was calculated as the difference between total chlorine residual and free chlorine residual. Results are shown in Table 5.1-6 and Figures 5.1-7 and 5.1-8. As shown in Figure 5.1-7, the constant concentrations of free chlorine indicates that addition of 1 mg/L PCP additives did not have a significant impact on the chlorine system. Compared with the control samples, none of the PCP additive spiked sample produced significant concentration of combined chlorine at time of 24 hours. However, results in Section 4.3.2 showed an obvious formation of combined chlorine from samples with PCP additives A1 (diethanolamine) and A4 (triethanolamine) during the breakpoint test. Thus, it suggests that a real water matrix may have a suppressing effect on the reactivity of these PCP additives or the 1 mg/L dose of PCP additives was a small concentration relative to the concentration of other reactive species in the water matrix (control).

118

Table 5.1-6 Concentration of free and combined chlorine in outdoor swimming pool (Out3) spiked

with PCP additives A1 to A10 individually

1.5 hours 24 hours 1.5 hours 24 hours Sample free chlorine free chlorine Combined Combined ID (mg/L) (mg/L) chlorine (mg/L) chlorine (mg/L) (Out3)-A1 9.05 8.23 1.97 1.82 (Out3)-A2 9.25 7.93 1.32 1.73 (Out3)-A3 9.55 8.32 1.62 1.88 (Out3)-A4 9.20 7.62 1.52 1.53 (Out3)-A5 9.63 8.60 1.72 1.58 (Out3)-A6 9.75 8.40 1.50 1.70 (Out3)-A7 9.68 8.38 1.55 1.43 (Out3)-A8 9.82 8.43 1.42 1.77 (Out3)-A9 9.85 8.13 1.75 1.73 (Out3)-A10 9.75 8.57 1.55 1.52 (Out3)-Ctl 9.52 7.63 1.75 1.75 (Out3-Ctl) means unspiked swimming pool (Out3) water.

1.5 hours free chlorine 24 hours free chlorine

3 Concentration (mg/L)

Figure 5.1-7 Concentration of free chlorine in outdoor swimming pool (Out3) water spiked with

PCP additives A1 to A10 individually

119

1.5 hours combined chlorine 24 hours combined chlorine 2.5

2.0

1.5

1.0

0.5 Concentration (mg/L) Concentration 0.0

Figure 5.1-8 Concentration of combined chlorine in outdoor swimming pool (Out3) water spiked

with PCP additives A1 to A10 individually

5.1.2.2 Influence on THM formation

Possible influence of PCP additives on the formation of THMs was investigated. As shown in Table 5.1-7 and Figure 5.1-9, PCP additives A4 (triethanolamine) potentially increased the formation of THMs in the Out3 pool water matrix (10%). On the contrary, PCP additives A6 (cetyltrimethylammonium chloride) and A8 (cocamidopropyl betaine) showed some potential of suppressing THM formation in Out3 pool water matrix, and THM concentrations for both additives decreased approximately 10 %. There was no significant difference in THM formation for other PCP additives compared with the control sample.

In addition, results of THMs in Out3 pool water are totally opposite to the results from simulated swimming pool water test in Section 4.3.3.2, where PCP additive A6 (cetyltrimethylammonium chloride) exhibited the highest THM formation potential in simulated swimming pool water. It shows that THM formation potential of A6 can be totally suppressed by water matrix effects from Out3 pool water.

120

Table 5.1-7 Concentration of THMs in outdoor swimming pool (Out3) spiked with PCP additives

A1 to A10 individually

Sample ID THMs (µg/L) (Out3)-A1 1333 (Out3)-A2 1330 (Out3)-A3 1303 (Out3)-A4 1446 (Out3)-A5 1255 (Out3)-A6 1168 (Out3)-A7 1254 (Out3)-A8 1194 (Out3)-A9 1360 (Out3)-A10 1340 (Out3)-Ctl 1308 (Out3-Ctl) means unspiked swimming pool (Out3) water.

1600

1200

800

400 TTHMConcentration (µg/L) 0

Figure 5.1-9 Concentration of THMs in outdoor swimming pool (Out3) water spiked with PCP

additives A1 to A10 individually

5.1.2.3 Influence on HAA formation

Results shown in Table 5.1-8 and Figure 5.1-10 are the formation of HAA9 (primarily MCAA/DCAA/TCAA) from PCP additives spiked into Out3 pool water. No significant influence on HAA formation was found from the addition of 1 mg/L PCP additives in

121 the Out3 pool water matrix. Since there was as high as 2500 µg/L HAA9 in the control sample without the spike of PCP additives, the formation of small amount of HAA9 from these PCP additives may not be significant. Nonetheless, as shown in Table 5.1-8, PCP additives A1 (diethanolamine), A2 (Padimate O), and A3 (nitilotriacetic acid) did show approximately 100 µg/L formation of HAA9, which is approximately 15% lower than their HAA formation in simulated swimming pool water with reaction time of 48 hours(shown in Table 4.3-13). On the contrary, HAA formation from PCP additives A4 (triethanolamine) and A7 (choline chloride) was relatively smaller compared with other additives and control sample, indicating that A4 and A7 may suppress HAA formation in Out3 pool water matrix. Results will be further compared with the results in indoor swimming pool water matrix which has lower background.

Table 5.1-8 Concentration of HAA9 and main species in outdoor swimming pool (Out3) spiked

with PCP additives A1 to A10 individually

Sample ID HAA9 (µg/L) MCAA (µg/L) DCAA (µg/L) TCAA (µg/L) (Out3)-A1 2639 270 1404 962 (Out3)-A2 2680 303 1409 968 (Out3)-A3 2670 283 1412 972 (Out3)-A4 2477 278 1299 898 (Out3)-A5 2582 275 1387 918 (Out3)-A6 2521 281 1331 906 (Out3)-A7 2381 264 1253 864 (Out3)-A8 2540 294 1325 921 (Out3)-A9 2527 285 1355 887 (Out3)-A10 2536 291 1347 898 (Out3)-Ctl 2492 281 1319 891 (Out3-Ctl) means unspiked swimming pool (Out3) water.

122

MCAA DCAA TCAA HAA9 2800

2100

1400

700

Concentration (µg/L) Concentration 0

HAA9

TCAA

(Out3)-A1

(Out3)-A2

DCAA

(Out3)-A3

(Out3)-A4

(Out3)-A5

MCAA

(Out3)-…

(Out3)-A6

(Out3)-A7

(Out3)-A8 (Out3)-A9 (Out3)-Ctl

Figure 5.1-10 MCAA, DCAA, TCAA and HAA9 in outdoor swimming pool (Out3) water spiked

with PCP additives A1 to A10 individually

5.1.2.4 Influence on nitrosamine formation

In this set of experiments with Out3 pool water, only NDMA, NDEA, and NDBA were detectable and results are shown in Table 5.1-9 and Figure 5.1-11. Other nitrosamines were below their MDL and are not reported. NDMA was barely measurable at a few ng/L. Compared with the control sample, the addition of PCP additives increased NDEA formation by 30% for A3 (nitrilotriacetic acid) and approximately 70% for A1 (diethanolamine), A2 (Padimate O), and A4 (triethanolamine). Compared with the observation that none of PCP additives showed any NDEA formation potential in the previous test (Sections 4.3.3 and 4.3.4) with chlorination or chloramination, the formation of NDEA in the Out3 pool water indicates that some components in the Out3 pool water may promote the conversion of PCP additives to NDEA, and/or the addition of PCP additives may potentially increase the transformation of original NDEA precursor in the Out3 pool water to NDEA.

In terms of NDBA, Figure 5.1-11 shows that PCP additives A1 (diethanolamine) and A3 (nitriloacetic acid) potentially increased NDBA formation at approximately 20%

123 compared with the control sample. On the contrary, NDBA formation was decreased approximately 47% for PCP additives A8 (cocamidopropyl betaine) and A7 (choline chloride), and approximately 25% for PCP additives A10 (tetramethylammonium chloride). Other PCP additives did not show any significant influence on NDBA formation in the Out3 pool water matrix.

Table 5.1-9 Concentration of nitrosamines (NDMA/NDEA/NDBA) in outdoor swimming pool

(Out3) spiked with PCP additives A1 to A10 individually

Sample ID NDMA (ng/L) NDEA (ng/L) NDBA (ng/L) (Out3)-A1 3.86 113 171 (Out3)-A2 4.81 112 146 (Out3)-A3 2.13 88 171 (Out3)-A4 1.53 112 140 (Out3)-A5 1.05 108 148 (Out3)-A6 1.05 97 136 (Out3)-A7 0.81 89 82 (Out3)-A8

NDMA NDEA NDBA 200

160

120

40 Concentration (ng/L) Concentration

(Out3)-A1

NDBA

(Out3)-A2

(Out3)-A3

NDEA

(Out3)-A4

(Out3)-A5

(Out3)-A6

NDMA

(Out3)-A7

(Out3)-A8

(Out3)-A9

(Out3)-Ctl (Out3)-A10

Figure 5.1-11 NDMA, NDEA, NDBA in outdoor swimming pool (Out3) water spiked with PCP

additives A1 to A10 individually

124

5.1.3 Influence of stabilizer (cyanuric acid) and humic acid on DBP

formation in outdoor swimming pool (Out3) water

Stabilizer is widely used in outdoor swimming pools to help maintain the concentration of disinfectant, mainly to prevent the photolysis of free chlorine under direct sun irradiation. One of the most popular stabilizers is cyanuric acid, and its molecular structure is shown in Figure 5.1-12. Photolysis of HOCl primarily produces hydroxyl radicals (∙OH) and chlorine radicals (∙Cl) (Nowell and Hoigne, 1992). Consequently, chain reactions with organic matter will decompose HOCl in the aqueous as listed in Equations 5.1-1 to 5.1-4 (Oliver and Carey, 1977; Feng et al., 2007).

Figure 5.1-12 Molecular structure of cyanuric acid

Equation 5.1-1  OH  RH   R  H2O

Equation 5.1-2  R  HOCl  RCl   OH

Equation 5.1-3  Cl  RH   R  HCl

Equation 5.1-4  R  HOCl  ROH   Cl

Cyanuric acid is used as a reservoir to keep the concentration of free chlorine relatively stable by the formation of sodium dichloroisocyanurate and/or trichloroisocyanuric acid in outdoor swimming pool water. When photolysis of free chlorine occurs, chlorocyanuric acid will hydrolyze in water to form HOCl thus help maintain the disinfectant concentration in the pool especially when there is a strong irradiation during the day time. Concentration of cyanuric acid used in this study was 30 mg/L, which is similar to that applied in outdoor swimming pools of 30 to 50 mg/L (Missouri

125 department of health and senior service section for environmental public health).

In addition, the effects of humic acid on DBP formation under condition of outdoor swimming pool (Out3) water matrix were also investigated. The concentration of 1 mg/L humic acid was used considering its macromolecule may provide too much influence on water matrix at higher concentration (Lavrik and Mulloev, 2010). Samples were incubated in 1 liter amber bottles for 24 hours at room temperature.

5.1.3.1 Influence on combined chlorine formation

Free chlorine and total chlorine were measured at times of 1.5 hours and 24 hours to examine the influence of cyanuric acid and humic acid on the formation of combined chlorine. As shown in Figures 5.1-13 and 5.1-14, the addition of cyanuric acid increased free chlorine concentration at both 1.5 hours and 24 hours but did not affect the formation of combined chlorine significantly compared with the control sample. It indicates that addition of cyanuric acid slowed down the consumption of chlorine in outdoor swimming pool (Out3) water matrix. This agrees with the results in Section 4.3.1 that the addition of cyanuric acid lowered free chlorine consumption in simulated swimming pool water.

The addition of humic acid did not show any obvious influences on free chlorine concentration at both 1.5 hours and 24 hours but decreased combined chlorine concentration within 1.5 hours. It indicates that there was a fast reaction between humic acid and combined chlorine within 1.5 hours, and combined chlorine was then maintained constant afterwards up to 24 hours whereas free chlorine were consumed similarly to that in the control sample.

126

1.5 hours free chlorine 24 hours free chlorine 5

1 Concentration (mg/L) Concentration 0

Figure 5.1-13 Concentration of combined chlorine in outdoor swimming pool (Out3) water spiked

with cyanuric acid and humic acid individually

1.5 hours combined chlorine 24 hours combined chlorine 1.5

1.2

0.9

0.6

0.3 Concentration (mg/L) Concentration 0.0

Figure 5.1-14 Concentration of free chlorine in outdoor swimming pool (Out3) water spiked with

cyanuric acid and humic acid individually

5.1.3.2 Influence on THM formation

Figure 5.1-15 shows the formation of THMs in the presence of cyanuric acid and humic acid in the outdoor swimming pool (Out3) water. It is found that both cyanuric acid of 30 mg/L and humic acid of 1 mg/L did not affect THMs formation significantly

127 compared with control sample. Even though humic acid is a potential precursor of THMs, no significant difference in THMs formation between humic acid spiked water and control sample indicates that 1 mg/L humic acid may not be sufficient to give a significant formation of THMs in the outdoor swimming water.

1500

1200

900

600

300 TTHM Concentration (µg/L) Concentration TTHM 0

Figure 5.1-15 Concentration of THMs in outdoor swimming pool (Out3) water spiked with

cyanuric acid and humic acid individually

5.1.3.3 Influence on HAA formation

As shown in Figure 5.1-16, HAA formation as a result of the addition of either cyanuric acid or humic acid was not significant changed compared with control sample. Although higher concentration of free chlorine was maintained in the water within 24 hours due to the stabilizing effect of cyanuric acid on free chlorine as shown in Section 5.1.3.1.1, no significant difference in HAA formation between cyanuric acid spiked water and control sample indicates that little HAA precursor existed in the Out3 pool water or the original HAA precursors in the Out3 pool water have already been converted to HAA. Therefore, compared with control sample, there was no additional formation of HAA observed during the test period.

128

MCAA DCAA TCAA HAA9

2000

1600

1200

800

Concentration (µg/L) Concentration 400

HAA9

TCAA

DCAA

MCAA

(Out3)-Cy

(Out3)-H (Out3)-Ctl

Figure 5.1-16 Concentration of MCAA, DCAA, TCAA and HAA9 in outdoor swimming pool

(Out3) water spiked with cyanuric acid and humic acid individually

5.1.3.4 Influence on nitrosamine formation

Figure 5.1-17 shows the formation of nitrosamine in cyanuric acid and humic acid spiked water samples. With addition of cyanuric acid and humic acid, there was no increased formation of NDMA for both cyanuric acid and humic acid compared with control sample. On the contrary, it was observed that NDEA and NDBA formation decreased 10% and 15%, respectively, in the water with the addition of humic acid. In addition, NDBA formation was also decreased 10% in the water spiked with cyanuric acid. Given that neither cyanuric acid nor humic acid exhibited nitrosamine formation potential with chlorination (as shown in Section 4.3.3), it is reasonable not to observe any increased formation of nitrosamine. However, decreased formation of NDBA and NDEA due to the addition of humic acid and/or cyanuric acid was unexpected. It implies that the addition of cyanuric acid or humic acid may cause some small changes on nitrosamine formation kinetics.

129

NDMA NDEA NDBA

150

120

30 Concentration (ng/L) Concentration

NDBA

NDEA

NDMA

(Out3)-Cy

(Out3)-H (Out3)-Ctl

Figure 5.1-17 Concentration of nitrosamines (NDMA/NDEA/NDBA) in outdoor swimming pool

(Out3) water spiked with cyanuric acid and humic acid individually

5.1.4 Summary

Results from experiments on outdoor swimming pool (Out3) water matrix showed that BFA compound #7 (creatinine) produced high concentration of combined chlorine; whereas BFA compound #3 (histidine) showed a low free chlorine concentration after 24 hours. None of the PCP additives produced significant concentrations of combined chlorine. The addition of cyanuric acid corresponded to higher concentration of both combined chlorine and free chlorine, while humic acid had no obvious influence on free chlorine concentration but decreased combined chlorine within 1.5 hours in the Out3 pool water matrix.

BFA compounds did not affect THM formation. PCP additives A4 (triethanolamine) potentially increased the formation of THMs in Out3 pool water matrix, while PCP additives A6 (cetyltrimethylammonium chloride) and A8 (cocamidopropyl betaine) showed a potential suppressing effect on THM formation which is totally opposite to the results from simulated swimming pool water test in Section 4.3.3.2 where PCP additives A6 and A8 showed highest THM formation. Neither cyanuric acid nor humic

130 acid significantly influenced THM formation in Out3 pool water matrix.

BFA compounds #6 (citric acid) and #7 (creatinine) promoted the formation of HAA9 while other BFA compounds #2 (urea), #4 (hippuric acid) and #5 (uric acid) suppressed HAA formation. PCP additives A1 (diethanolamine), A2 (Padimate O), and A3

(nitilotriacetic acid) showed approximately 100 µg/L formation of HAA9. On the contrary, PCP additives A4 (triethanolamine) and A7 (chloline chloride) showed potential suppression of HAA formation. No significant change of HAA formation was observed due to the addition of either cyanuric acid or humic acid.

BFA compounds #2 (urea), #3 (histidine), #5 (uric acid), #6 (citric acid), and #7 (creatinine) showed a suppressing effect on NDBA formation. The addition of PCP additives potentially increased NDEA formation by 30% for A3 (nitrilotriacetic acid), and 70% for A1 (diethanolamine), A2 (Padimate O), and A4 (triethanolamine). PCP additives A1 (diethanolamine) and A3 (nitriloacetic acid) potentially increased NDBA formation by approximately 20%. On the contrary, NDBA formation was decreased approximately 47% in the presence of PCP additives A8 (cocamidopropyl betaine) and A7 (choline chloride) and approximately 25% by PCP additives A10 (tetramethylammonium chloride. The addition of humic acid slightly decreased NDEA and NDBA formation, and the addition of cyanuric acid slightly decreased the formation of NDBA as well.

131 5.2 Influence of BFA base mix compounds, PCP additives and humic acid on the formation of DBPs in indoor pool water (Part IV)

Previous experiments on the outdoor swimming pool (Out3) water showed that there was a high background matrix which affected the formation of DBPs from the addition of BFA compounds, Personal Care Products (PCPs), stabilizer (cyanuric acid) and humic acid. Therefore, it was important to select a less complicated water matrix to further investigate DBP formation potential of these compounds. Given that the indoor swimming pool water generally has lower TOC and DBP concentrations, it could be a good choice to study the influence of BFA compounds, Personal Care Products (PCPs), pool stabilizer (cyanuric acid) and humic acid on DBP formation in the indoor swimming pool water.

In total, there were five indoor swimming pools included in this thesis. In order to make the selection more representative and more valuable, the one with a relatively low TOC and DBP concentration was chosen as the water source for this part of experiments, namely indoor swimming pool #2 (In2). This ensured that background matrix was small enough so that observations of DBP formation due to the addition of BFA compounds, Personal Care Products (PCPs), pool stabilizer (cyanuric acid) and humic acid could be made. Therefore, the purpose of this section of experiments was to examine the influence of BFA compounds, Personal Care Products (PCPs), pool stabilizer (cyanuric acid) and humic acid on the formation of several classes of DBPs in indoor swimming pool bulk water. Significance of the influence from BFA compounds and PCP additives on DBP formation was t-tested and results are shown in Appendix 9.4.

132

5.2.1 Influence of BFA base mix compounds on DBP formation in

indoor swimming pool (In2) water

BFA compounds used in this study included BFA compounds #2 (urea), #3 (L-histidine), #4 (hippuric acid), #5 (uric acid), #6 (citric acid), and #7 (creatinine). Their concentrations are shown in Table 5.2-1. It should be noted that BFA compound #1 (ammonium chloride) was not spiked into swimming pool sample considering that its reaction with free chlorine would exceed the breakpoint as high concentrations of free chlorine are used to treat swimming pool water. The BFA compounds were added into indoor swimming pool (In2) bulk water. Reactions were performed in amber bottles under room temperature. Samples were incubated for 24 hours before measurements were made.

Table 5.2-1Concentrations of BFAs used for In2 pool water experiment Ingredient ID Concentration (mg/L) Ammonium chloride BFA #1 2 Urea BFA #2 14.8 Histidine BFA #3 1.21 Hippuric acid BFA #4 1.71 Uric acid BFA #5 0.49 Citric acid BFA #6 0.64 Creatinine BFA #7 1.8

5.2.1.1 Influence on combined chlorine formation

Free and total chlorine were measured at an incubation time of 1.5 hours and 24 hours. The measurements at 1.5 hours ensured that free chlorine residual at 1.5 hours was at least 1.5 mg/L (in this case only 3 of them were higher than 1.5 due to unexpected free chlorine consumption from interaction between pool water and added BFA compounds), which would be enough to satisfy the free chlorine demand throughout the total 24 hours incubation time. Measurements at 24 hours provided the final free and total chlorine residual, which were used to calculate the concentration of combined chlorine in the bulk water by difference.

133

Concentrations of free chlorine are shown in Figure 5.2-1, BFA compounds #2 (urea), #3 (histidine), #5 (uric acid) and #7 (creatinine) significantly consumed free chlorine at both 1.5 hours and 24 hours. Compared with the results for Out3 pool water in Section 5.1.1.1 where there was still 3 mg/L free chlorine at 24 hours for BFA compounds #2 (urea) and #5 (uric acid) , less than 0.5 mg/L free chlorine residual remained for both compounds in the indoor swimming pool water. Therefore, it can be concluded that water matrix had a significant effect on free chlorine consumption in particularly for BFA compounds #2 (urea) and #3 (histidine). In addition, significant decrease of free chlorine for BFA compound #2 (urea) did not lead to dramatic increase of combined chlorine formation (shown in Figure 5.2-2). It indicates that free chlorine was consumed by reactions not involving organic nitrogen

As shown in Figure 5.2-2, BFA compound #7 (creatinine), produced the highest concentration of combined chlorine among all of the BFA compounds. This is consistent with the previous results in Section 5.1.1.1. Other BFA compounds showed relatively similar formation potential of combined chlorine to the control sample, indicating that they do not form relatively stable organic chloramine compounds.

1.5 hours free chlorine 24 hours free chlorine 3.0

2.5

2.0

1.5

1.0 Concentration (mg/L) Concentration 0.5

0.0 (In2)-2 (In2)-3 (In2)-4 (In2)-5 (In2)-6 (In2)-7 (In2)-Ctl

Figure 5.2-1 Concentration of free chlorine in In2 pool water spiked with BFA compounds

individually at time of 1.5 hours and 24 hours

134

1.5 hours combined chlorine 24 hours combined chlorine 2.5

2.0

1.5

1.0

Concentration (mg/L) Concentration 0.5

0.0 (In2)-2 (In2)-3 (In2)-4 (In2)-5 (In2)-6 (In2)-7 (In2)-Ctl

Figure 5.2-2 Concentration of combined chlorine in In2 pool water spiked with BFA compounds

individually at time of 1.5 hours and 24 hours

5.2.1.2 Influence on THM formation

The Formation potentials of THMs from BFA compounds when spiked into indoor pool water are shown in Figure 5.2-3. None of the BFA compounds showed significant THM formation compared with the control sample of In2 pool water. This is consistent with the results from experiments on the Out3 pool water. No significant formation of THMs in BFA compounds (1mg/L individually) spiked swimming pool water indicates that either (i) the concentration of BFA compounds (1 mg/L) may not be high enough to produce significantly high concentration of THM compared with the concentration of THM that were already formed in the swimming water, or (ii) these compounds are not precursors for THMs (either alone or combined with other pool components).

135

200

160

120

Concentration (ug/L) Concentration 40

0 (In2)-2 (In2)-3 (In2)-4 (In2)-5 (In2)-6 (In2)-7 (In2)-Ctl

Figure 5.2-3 Concentration of THMs in In2 pool water spiked with BFA base mix compounds

individually at time of 24 hours

5.2.1.3 Influence on HAA formation

Figure 5.2-4 shows the formation of HAA9 and three primary HAA species (MCAA/DCAA/TCAA) from BFA compounds #2 to #7 when they were spiked into indoor pool water. No significant formation or suppression of HAA9 was observed due to the addition of BFA compounds into In2 pool water. Similar explanation can be applied that HAA formation from BFA compounds may not be significant in comparison with the concentration of HAA in the water matrix. Although BFA compound #6 (citric acid) had shown HAA formation potential in the Out3 pool water test, it could be because chlorine concentration in the Out3 pool water was much higher (~ 5 mg/L) than that in In2 pool water (~ 2 mg/L). In terms of HAA speciation, it is interesting to find that TCAA was a dominant species over MCAA and DCAA, which is different from the observation in the Out3 pool water where DCAA was dominant. Difference in the distribution of HAA species in the outdoor and indoor swimming water was likely because the two water sources had different organic compositions, and DCAA precursors were primarily present in the outdoor water whereas the indoor water contained primarily TCAA precursors.

136

MCAA DCAA TCAA HAA9 500

400

300

200

Concentration (ug/L) Concentration 100

0 (In2)-2 (In2)-3 (In2)-4 (In2)-5 (In2)-6 HAA9

(In2)-7 TCAA

(In2)-Ctl

DCAA MCAA

Figure 5.2-4 MCAA, DCAA, TCAA and HAA9 in In2 pool water spiked with BFA base mix

compounds individually at time of 24 hours

5.2.1.4 Influence on DMA, NMOR and NDEA formation

The formation potentials of nitrosamines from BFA compounds when spiked into indoor pool water are shown in Figure 5.2-5. Only NDMA, NMOR and NDEA were detectable. NDEA formation was increased by approximately 100% for BFA compounds #3 (L-histidine), #4 (hippuric acid), #5 (uric acid), #6 (citric acid) and #7 (creatinine) compared with the control sample and sample added with BFA compound #2 (urea). However, there was no significant formation of NDMA and NMOR due to the addition of BFA compounds except for an increase of 3ng/L and 4 ng/L of NDMA and NMOR, respectively, from the addition of BFA compounds #5 (uric acid).

Given that BFA compounds were not shown to be potential precursors of NDEA according to the results in the tests with simulated swimming pool water (shown in Section 4.3.4.2), significant formation of NDEA ins spiked pool water indicates that the BFA compounds may interact with other pool water components to influence the formation potential of nitrosamines, illustrating a water matrix effect.

137

In the previous case of Out3 pool water spiked with BFA compounds, there was a 30% to 40% suppression of NDBA formation with addition of BFA compounds #2 (urea), #3 (histidine), #5 (uric acid), #6 (citric acid), and #7 (creatinine). In this case of In2 pool water, NDEA formation was promoted by the addition of specific BFA compounds. In comparison, it indicates that NDBA precursors in Out3 pool water tend to be suppressed rather than promoted to form NDBA in pool water, whereas NDEA precursors in In2 pool water tend to be promoted rather than suppressed to form NDEA.

NDMA NMOR NDEA 50

Concentration (ng/L) Concentration 10

0 (In2)-2 (In2)-3 (In2)-4 (In2)-5 (In2)-6

(In2)-7 NDEA

(In2)-Ctl

NMOR NDMA

Figure 5.2-5 NDMA, NMOR and NDEA in In2 pool water spiked with BFA base mix compounds

individually at time of 24 hours

5.2.2 Influence of PCP additives on DBP formation in indoor

swimming pool (In2) water

PCP additives were examined regarding their DBP formation potential and their effects on DBP formation in the indoor swimming pool (In2) bulk water. PCP additives were spiked into the In2 pool water at concentration of 1 mg/L and samples were incubated for 24 hours under room temperature before DBPs were sampled and analyzed.

138

5.2.2.1 Influence on combined chlorine formation

As shown in Figures 5.2-6 and 5.2-7, at the reaction time of 24 hours, all samples spiked with PCP additives exhibited lower free and combined chlorine than the control sample of the In2 pool water alone. This indicates that addition of PCP additives potentially accelerated the degradation of free and combined chlorine in In2 pool water. This is extremely interesting for sample added with PCP additives A1 (diethanolamine) and A4 (triethanolamine) since they have shown formation potential of combined chlorine during free chlorine breakpoint test (shown in Section 4.3.2). It implies that their combined chlorine formation potential is less powerful than their potency of accelerating combined chlorine degradation in In2 pool water matrix.

In addition, between the reaction times of 1.5 hours and 24 hours, all of the In2 pool samples added with PCP additives exerted approximately 2 mg/L free chlorine demand which is even higher than their approximately 1 mg/L demand in Out3 pool water. Moreover, there was approximately 0.5 mg/L combined chlorine decrease in In2 pool water with PCP additives whereas there was slight formation of combined chlorine in Out3 pool water. These results indicate that there are different organic components in Out3 pool water and In2 pool water. The combined chlorine in Out3 pool water is more stable than that in In2 pool water, whereas the combined chlorine in In2 pool water is fresher and tends to degrade with time.

Results in Figure 5.2-7 show the variation of combined chlorine at a time of 1.5 hours and 24 hours. Combined chlorine significantly formed for PCP additive A1 (diethanolamine) at 1.5 hours, and it was increased by 0.6 mg/L compared with the control sample. The addition of A4 (triethanolamine) and A8 (cocamidopropyl betaine) also led to a slight increase of combined chlorine, which was 0.2 mg/L higher than that in the control sample at time of 1.5 hours. Correspondingly, free chlorine decreased 0.6 mg/L and 0.2 mg/L due to addition of A1 and A8, respectively, whereas free chlorine decreases 1 mg/L due to addition of A4. It indicates that there was a faster formation of

139 combined chlorine due to the addition of these PCP additives rather than the addition of other PCP additives. Molecular structures of A1 (diethanolamine), A4 (triethanolamine) and A8 (cocamidopropyl betaine) are shown in Figures 5.2-8 to 5.2-10. It indicates that these molecules, containing either secondary amino group or tertiary amino group with small branches, are readily to be added by –Cl group to form combined chlorine, or that there were amino impurities in the compounds that could readily react with chlorine.

1.5 hours free chlorine 24 hours free chlorine 3.0

2.5

2.0

1.5

1.0

Concentration (mg/L) Concentration 0.5

0.0 (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 Ctl

Figure 5.2-6 Concentration of free chlorine in (In2) swimming pool water spiked with PCP

additives individually at time of 1.5 hours and 24 hours

1.5 hours combined chlorine 24 hours combined chlorine 2.0

1.6

1.2

0.8

Concentration (mg/L) Concentration 0.4

0.0 (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 Ctl

Figure 5.2-7 Concentration of combined chlorine in (In2) swimming pool water spiked with PCP

additives individually at time of 1.5 hours and 24 hours

140

Figure 5.2-8 Molecular structure of PCP additive A1 diethanolamine

Figure 5.2-9 Molecular structure of PCP additive A4 triethanolamine

Figure 5.2-10 Molecular structure of PCP additive A8 cocamidopropyl betaine

5.2.2.2 Influence on THM formation

The effect of PCP additives on THM formation was investigated in this part. Results in Figure 5.2-11 show that there was no significant formation of THMs due to the addition of PCP additives in the In2 pool water. On the contrary, THM formation was decreased for samples added with PCP additives A10 (tetramethylammonium chloride), A7 (choline chloride), A8 (cocamidopropyl betaine), A3 (nitrilotriacetic acid) and A5 (tetrabutylammonium chloride). Results are different from the results in Out3 pool test where PCP additive A6 suppressed THM formation. However, it is partially consistent with the results in simulated swimming pool water test (shown in Section 4.3.3.2) where PCP additive A6 produced highest THM formation. These comparisons between Out3 pool water, In2 pool water and simulated swimming pool water confirm that THM formation is more vulnerable to water matrix rather than to any of the PCP compounds tested.

In addition, the decrease of THM formation in In2 pool water with PCP additives could

141 partially result from the decrease of free and combined chlorine during the test, which can potentially suppress THM formation. It should be noted that the magnitude of the decrease in free and combined chlorine is much larger than that of THMs (~55% vs ~25%, respectively), which indicates that THM formation is not controlled by free or combined chlorine concentration alone. Water matrix and precursors should be the most important factors.

300

250

200

150

100

Concentration (ug/L) Concentration 50

0 (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- (In2)- A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 Ctl

Figure 5.2-11 Concentration of total THM in (In2) swimming pool water spiked with PCP

additives individually at time of 24 hours

5.2.2.3 Influence on HAA formation

Figure 5.2-12 shows the results of HAA formation in the indoor swimming pool (In2) water with the addition of PCP additives. No significant formation of HAA by the addition of PCP additives was observed in comparison with the control sample.

However, there is a slight decrease of TCAA and HAA9 (5% and 5%, respectively) for all the samples added with PCP additives. Although these differences are statistically significant at the 95% level of confidence, they may be considered to be the same on a practical level. Theoretically, lower free and combined chlorine in samples added with PCP additives might attribute to the lower formation of HAA in the In2 pool water. Although PCP additive A3 (nitrilotriacetic acid) had showed high formation potential

142 of HAAs in Section 4.3.3.2, it did not show its HAA formation potential in the indoor swimming pool water.

In addition, compared with the high HAA9 concentration of approximately 2500 µg/L in the outdoor swimming pool (Out3) water, HAA9 concentration was only approximately 250 µg/L in the indoor swimming pool (In2) water. Moreover, dominant species in Out3 pool water (DCAA over TCAA) are different to those in In2 pool water (TCAA over DCAA), which should indicate different HAA precursors in these two swimming pools.

MCAA DCAA TCAA HAA9 300

250

200

150

100 Concentration (ug/L) Concentration 50

(In2)-A1

(In2)-A2

(In2)-A3

HAA9

(In2)-A4

(In2)-A5

TCAA

(In2)-A6

(In2)-A7

DCAA

(In2)-A8

(In2)-A9

MCAA

(In2)-Ctl (In2)-A10

Figure 5.2-12 MCAA, DCAA, TCAA and HAA9 in (In2) swimming pool water spiked with PCP

additives individually at time of 24 hours

5.2.2.4 Influence on NDMA, NMOR and NDEA formation

Influence of PCP additives on nitrosamine formation was investigated. Only NDMA, NMOR, and NDEA were detected in the indoor swimming pool (In2) water, and the results are shown in Figure 5.2-13. No significant influence on the formation of NDMA and NMOR were observed due to the addition of PCP additives in the In2 pool water.

The addition of PCP additives A2 to A10 significantly increased the formation of

143

NDEA ranging from 20% to 100%. For example, A9 (behentrimonium chloride) and A10 (tetraethylammonium chloride) increased NDEA formation by 100%. Based on the results obtained from the preliminary study in the relatively simpler matrix of simulated swimming pool water (Sections 4.3.3.2 and 4.3.4.2), none of the PCP additives could be potential NDEA precursors under condition of either chlorination or chloramination. However, it is possible that a wide variety of nitrosamine precursors exist in actual swimming pool water, including precursors of NDEA. The addition of PCP additives into the swimming pool water may accelerate the transformation of these precursors into NDEA and other nitrosamines. In general, these results are in agreement with the previous observation (Section5.2.1.4) that NDEA formation was readily promoted by BFA compounds rather than other nitrosamines in In2 pool water.

On the other hand, addition of PCP additive A1 (diethanolamine) suppressed NDEA formation by 30%. The suppression effect from A1 on NDEA formation could result from the fast formation of 0.7 mg/L combined chlorine (as shown in Section 5.2.2.1), which was formed through the reaction between free chlorine and diethanolamine, and thus made diethnolamine less available for NDEA formation.

NDMA NMOR NDEA 60

20 Concentration (ng/L) Concentration 10

(In2)-A1

(In2)-A2

(In2)-A3

(In2)-A4

(In2)-A5

(In2)-A6 NDEA

(In2)-A7

(In2)-A8

NMOR

(In2)-A9

NDMA (In2)-Ctl (In2)-A10

Figure 5.2-13 NDMA, NMOR and NDEA in (In2) swimming pool water spiked with PCP additives

individually at time of 24 hours

144

5.2.3 Influence of pool stabilizer (cyanuric acid) and humic acid on

DBP formation in indoor swimming pool (In2) water

As mentioned previously with respect to the results with the outdoor (Out3) pool water, pool stabilizer (cyanuric acid) is widely used in the outdoor swimming pool to minimize the photolysis of free chlorine due to the direct sun irradiance. In addition, it has been found in Out3 pool water experiment (shown in Section 5.1.3) that application of cyanuric acid could potentially increase the formation of THMs due to the capability of cyanuric acid to maintain high concentration of free chlorine in the outdoor swimming pools. Even though pool stabilizer is not often used in indoor swimming pools, it would be valuable to investigate the change of DBP formation due to the addition of cyanuric acid into the indoor swimming pool water. Cyanuric acid of 30 mg/L was added into the indoor swimming pool water in 1L amber bottles and incubated for 24 hours at room temperature.

Humic acid was the other additive which was investigated in terms of its DBP formation potential and possible influence on DBP formation in the indoor swimming pool (In2) bulk water. Concentration of humic acid was 1 mg/L and reactions were preceded in 1 liter amber bottles for 24 hours and under room temperature.

5.2.3.1 Influence on combined chlorine formation

Results of free and combined chlorine are shown in Figure 5.2-14 and 5.2-15. Compared with control sample, sample added with cyanuric acid maintained similar concentration of free chlorine and produced 0.25 mg/L less combined chlorine. This result is not consistent with the result in test with Out3 pool water, where addition of cyanuric acid corresponding to higher free chlorine residual and similar concentration of combined chlorine compared with control sample (shown in Section 5.1.3.1). It either indicates that combined chlorine in In2 pool water is active with cyanuric acid or implies that combined chlorine precursors are sensitive to the addition of cyanuric acid.

145

In detail, in pool water, free chlorine decays with time and combined chlorine decays and/or forms from free chlorine and precursors. In this case, the control sample of In2 pool water exhibited 0.5 mg/L free chlorine decay and 0.15 mg/ combined chlorine formation from time of 1.5 hours to 24 hours. Whereas sample added with cyanuric acid exhibited 0.5 mg/L free chlorine decay as well as 0.2 mg/L combined chlorine decay. Hypothetically, it means addition of cyanuric acid inhibited combined chlorine formation in In2 pool water but did not prevent other free chlorine consumption such as some slow inorganic reactions.

The addition of humic acid, however, exhibited slight lower (0.1 mg/L) formation of combined chlorine than the control sample, whereas it exhibited 0.6 mg/L more free chlorine consumption at time of 24 hours. Given that samples spiked with humic acid consumed 0.5 mg/L more free chlorine than control sample at 1.5 hours, it is reasonable that slightly lower formation of combined chlorine was observed.

1.5 hours free chlorine 24 hours free chlorine 3.0

2.5

2.0

1.5

1.0 Concentration (mg/L) Concentration 0.5

0.0 (In2)-Cy (In2)-H (In2)-Ctl

Figure 5.2-14 Concentration of free chlorine in (In2) swimming pool water spiked with PCP

additives individually at time of 1.5 hours and 24 hours

146

1.5 hours combined chlorine 24 hours combined chlorine 1.0

0.8

0.6

0.4

Concentration (mg/L) Concentration 0.2

0.0 (In2)-Cy (In2)-H (In2)-Ctl

Figure 5.2-15 Combined chlorine in (In2) swimming pool water spiked with PCP additives

individually at time of 1.5 hours and 24 hours

5.2.3.2 Influence on THM formation

As shown in Figure 5.2-16, THM concentration did not change significantly for 30 mg/L cyanuric acid compared with the control sample within the incubation period of 24 hours at room temperature, while it increased by approximately 30% for 1 mg/L humic acid. It further confirmed that cyanuric acid is not a precursor of THMs where humic acid has a great potential to form THMs (Rook, 1977; Rook, 1976; Oliver 1978; Trussell and Umphres, 1978; Miller and Uden, 1983; Christman et al., 1983; Reckhow and Singer, 1984).

147

240

200

160

120

80 Concentration (ug/L) Concentration 40

0 (In2)-Cy (In2)-H (In2)-Ctl

Figure 5.2-16 Concentration of TTHM (In2) swimming pool water spiked with PCP additives

individually at time of 24 hours

5.2.3.3 Influence on HAA formation

As shown in Figure 5.2-17, the addition of 30 mg/L of cyanuric acid or 1 mg/L of humic acid presented little additional formation of HAA9. Even though humic acid is potential precursor of HAA (Dickenson, 2005), the addition of 1 mg/L humic acid may not be high enough to produce significant HAAs compared to the high concentration of 400

µg/L HAA9 in the background of the In2 pool water.

148

MCAA DCAA TCAA HAA9 500

400

300

200

100 Concentration (ug/L) Concentration

0 (In2)-Cy (In2)-H HAA9

(In2)-Ctl TCAA

DCAA MCAA

Figure 5.2-17 MCAA, DCAA, TCAA and HAA9 in (In2) swimming pool water spiked with PCP

additives individually at time of 24 hours

5.2.3.4 Influence on NDMA, NMOR and NDEA formation

As shown in Figure 5.2-18, the concentrations of NDMA and NMOR were not influenced by the addition of 30 mg/L cyanuric acid or 1 mg/L of humic acid in the indoor swimming pool (In2) water. Their concentrations were similar to those in the control sample. This indicates that neither cyanuric acid nor humic acid could be potential precursors of NDMA and NMOR and/or they did not have any interactive effects on the behaviour of other potential precursors in the pool water matrix to form NDMA and NMOR.

On the contrary, an approximately 70% increased formation of NDEA was observed compared with in the control sample when 1 mg/L of humic acid was added into the In2 pool water. However, results in preliminary experiment (in Sections 4.3.3 and 4.3.4) have shown that humic acid cannot perform as NDEA precursor either with chlorination or with chloramination. Therefore, this indicates that increased NDEA formation might result from the reactions between pre-existing NDEA precursors in the

149

In2 pool water and chlorine and the transformation of NDEA precursors to NDEA is positively influenced by the addition of humic acid. Compared with results in Out3 pool water where cyanuric acid did not show any influence and humic acid showed slight suppression on NDEA formation (shown in Section 5.1.3.4), it implies that either there were no significant NDEA precursors in Out3 pool water or that the water matrix can substantially influence the effect of humic acid on NDEA formation.

NDMA NMOR NDEA 40

10 Concentration (ng/L) Concentration

0 (In2)-Cy (In2)-H

(In2)-Ctl NDEA

NMOR NDMA

Figure 5.2-18 Concentration of NDMA, NMOR and NDEA in (In2) swimming pool water spiked

with PCP additives individually at time of 24 hours

5.2.4 Summary

Experiments on the indoor swimming pool (In2) water show that BFA compound #7 (creatinine) produced a higher concentration of combined chlorine than other BFA compounds. BFA compounds #2 (urea), #3 (histidine), #5 (uric acid) and #6 (citric acid) significantly consumed free chlorine both at 1.5 hours and at 24 hours. PCP additive A1 (diethanolamine) produced 0.6 mg/L of combined chlorine while PCP additives A4 (triethanolamine) and A8 (cocamidopropyl betaine) increased 0.2 mg/L of combined chlorine in the In2 pool water. The concentration of combined chlorine slightly

150 decreased when the indoor swimming pool (In2) water was added with cyanuric acid and humic acid.

Neither BFA compounds nor PCP additives showed significant THM formation potential. On the contrary, THM formation was decreased for samples spiked with PCP additives A10 (tetramethylammonium chloride), A7 (choline chloride), A8 (cocamidopropyl betaine), A3 (nitrilotriacetic acid) and A5 (tetrabutylammonium chloride). Little change of THM concentration was observed due to the addition of 30 mg/L cyanuric acid, while there was an obvious increase of THMs due to the addition of 1 mg/L humic acid into the In2 pool water. None of BFA compounds, PCP additives, cyanuric acid and humic acid showed significant influence on HAA formation in the In2 pool water within 24 hours incubation.

NDEA formation was significantly increased by approximately 100% due to the addition of BFA compounds #3 (L-histidine), #4 (hippuric acid), #5 (uric acid), #6 (citric acid) and #7 (creatinine) compared with the control sample and samples spiked with BFA compound #2 (urea). No significant formation of NDMA and NMOR was observed due to the addition of BFA compounds. PCP additives A2 to A10 significantly increased the formation of NDEA from 20% by A3 (nitrilotriacetic acid) to 100% by A9 (behentrimonium chloride) and A10 (tetraethylammonium chloride), whereas PCP additive A1 (diethanolamine) suppressed 30% formation of NDEA in the In2 pool water. The addition of 1 mg/L of humic acid increased approximately 70% formation of NDEA while cyanuric acid did not show significant influence on NDEA formation in the In2 pool water.

151

Chapter 6 Conclusions

Conclusions

The main purpose of this thesis was to investigate the relationship between different classes of DBPs and the potential precursors of Body Fluid Analogues (BFAs) and Personal Care Products (PCPs) using swimming pool water as the test matrix. Following the measurements of ambient DBP concentrations in real swimming pool water, preliminary bench-scale experiments focused on DBP formation potential from BFAs and PCPs in simulated swimming pool water matrix. Subsequently, BFAs and PCPs were spiked into real swimming pool water to further investigate DBP formation from BFAs and PCP under pool water matrices.

6.1 Conclusions from measurements of ambient water quality of swimming pools

To the author’s knowledge, a comprehensive suite of DBPs in swimming pools were measured in a wide range of indoor vs. outdoor, on campus vs. in community, normal outdoor pools vs. outdoor hot tub in Ontario, Canada. And, different classes of DBPs were correlated to examine their relationship with each other in swimming pool water. High concentrations of DBPs were observed in swimming pool water which were hypothesized to be related to the high organic inputs from swimmers.

Measurements of real swimming pool water showed that TOC values (3 to 5 mg/L in indoor pools and up to 10 mg/L in hot tub) were not related to total bather load but related to bather load per 1000 liter pool water. For each individual swimming pool, TOC values were quite stable despite changes in the bather load which indicated that organic matter input from swimmers could be well controlled by the operating system when bather load is within the designed capacity. All swimming pools included in this

152 study exhibited low SUVA values (0.005 to 0.007 L/mg/cm) in spite of bather loads or types of pools, which implied that swimming pool water had low proportion of aromatic matter. However, despite the low proportion of aromatic matter, high concentrations of THMs and HAAs (hundreds of µg/L in indoor pool water and few thousand µg/L in outdoor pool) were found in swimming pool water, which implies that reactivity of swimming pool water and DBP formation in swimming pool relies on other types of organic compounds, such as body fluids and personal care products, rather than NOM. In addition, generally, concentrations of THMs and HAAs were correlated to bather load per 1000 liter pool water and tended to be influenced by total bather load. However, measurements of organic chloramines and nitrosamines showed that neither of them was correlated to bather load. As well, despite the low concentration of NDMA, opposite formation trends between organic chloramines and nitrosamines (NDMA) were observed in some swimming pool water, which could be of high interest for future research.

Shocking treatment by sodium monopersulfate significantly decreased the concentration of organic chloramines. On the contrary, little influence was found on the formation of all other measured DBPs from shocking treatment of swimming pool, which indicated that monopersulfate is not strong enough to oxidize NOM or DBPs directly.

Higher concentrations of THMs and HAA9 were present in outdoor swimming pools. In comparison, indoor swimming pools are normally open all year around whereas outdoor swimming pools could only be open during summer time. However, outdoor swimming pools normally have a heavier bather load given the hot summer weather and the desire for people to cool off. Therefore, TOC values were higher in outdoor pools than those in indoor pools. In addition, increments of THM concentrations were more obvious than those for HAA concentrations which implied that THMs may more readily formed from precursors such as body fluids or sunscreen given that, normally, outdoor swimmers excrete more body fluid and use more sunscreen than indoor

153 swimmers. Concentrations of NDMA were similarly low in both indoor and outdoor swimming pools which implied a low NDMA formation potential from body fluid and personal care products, such as sunscreen and body lotion. Still, higher concentrations of other nitrosamine species could indicate the presence of other nitrosamine precursors in swimming pool water.

6.2 Conclusions from preliminary bench-scale tests

Simulated swimming pool water containing Body Fluid Analogue (BFA) compounds was used as a fundamental matrix to investigate the influence on DBP formation from the addition of Personal Care Product (PCP) additives, swimming pool stabilizer (cyanuric acid) and humic. In addition, DBP formation potentials of BFAs, PCPs, pool stabilizer (cyanuric acid) and humic acid with both chlorination and chloramination (monochloramine) were investigated.

Results indicated that most of the free chlorine demand and formation of combined chlorine were quickly completed within short time (1.5 hours) and DBP formation mainly completed within 48 hours. Results also indicated that free chlorine demand was reduced due the formation of unstable combined chlorine (which still can be reactive as chlorine for some other reactions in long time) with the addition of PCP additives and cyanuric acid.

DBP measurements showed that simulated swimming pool water had high formation potential of THMs (100 µg/L) and HAAs (200 µg/L) under condition of chlorination. In addition, PCP additives cetyltrimethylammonium chloride and nitrilotriacetic acid showed approximately 150 µg/L THM and 150 µg/L HAA formation potential, respectively, in simulated swimming pool water. On the contrary, most of the PCP additives and BFA compounds did not show high nitrosamine formation potential regardless of chlorination or chloramination which supported the low nitrosamine concentrations in swimming pool water.

154

6.3 Conclusions from real swimming pool water tests

Previous measurements of swimming pool water showed that higher organic inputs corresponded to high THM and HAA formation. In addition, BFAs and PCPs showed high DBP formation potentials with chlorination in simulated swimming pool water. Therefore, it was of interest to further investigate the DBP formation in real swimming pool water matrices under the influence of BFAs and PCPs. Outdoor swimming pools and indoor swimming pools were both examined as background water matrices.

Results from outdoor pool experiments showed that creatinine (a BFA compound) produced the highest formation of combined chlorine whereas other BFAs and PCPs did not show significant influence. In addition, BFA compounds urea, L-histidine, uric acid, citric acid, creatinine, PCP additives choline chloride, cocamidopropyl betaine, Tetramethylammonium chloride, cyanuric acid and humic acid suppressed NDBA formation by 15% to 55%. On the contrary, PCP additives promoted NDEA formation by 25% to 70%. Otherwise, generally, the outdoor hot tub water had an extremely high background matrix which inhibited the possible influence of BFAs and PCPs on DBP formation or as potential DBP precursors.

Indoor swimming pool water (simpler water matrix and lower DBP background than outdoor pool water) was further investigated with the expectation of more conclusive observations from BFAs and PCPs. Results showed that the BFA compound creatinine exhibited highest combined chlorine and other BFAs did not shown significant influence. However, PCPs showed significant decrease in free chlorine and combined chlorine formation. In addition, suppression of THM formation from PCP additives nitrilotriacetic acid, tetrabutylammonium chloride, choline chloride, cocamidopropyl betaine and tetramethylammonium chloride and promotion of THM formation from humic acid were observed. Suppression could come from the formation of combined chlorine and depletion of free chlorine upon reaction with PCP additives. Moreover,

155 promoted NDEA formation of 28% to 100% was observed from BFA compounds (including L-histidine, hippuric acid, uric acid, citric acid, creatinine), PCP additives (including padimate O, nitrilotriacetic acid, triehanolamine, tetrabutylammonium chloride, cetyltrimethylammonium chloride, choline chloride, cocamidopropyl betaine, behentrimonium chloride, tetramethylammonium chloride) and humic acid. Otherwise, no significant influence on HAA formation or other DBP formation was observed from the addition of organic compounds.

In addition, different HAA species in indoor pools and outdoor pools were observed which indicated that different HAA precursors existed in indoor and outdoor pools. There were more DCAA precursors in outdoor swimming pool water, possibly from more sweat or more sunscreen.

156

Chapter 7 Recommendations

Recommendations

Recommendations for future work and current operating design will be stated in this chapter.

7.1 Recommendations for future work

When Body Fluid Analogues (BFAs) and Personal Care Products (PCPs) are used as experimental DBP precursor materials, higher concentration of BFAs and PCPs should be considered to enhance their effects on DBP formation or property as potential DBP precursors.

In addition, despite the generally low concentration of NDMA in all pools, more research could be focused on the formation of other nitrosamine species. Opposite formation trends between organic chloramines and nitrosamines were also observed in some swimming pool water. Therefore, relationship between organic chloramines and nitrosamines could be of interest for future research.

More future work could include closer investigation of the DBP formation in swimming pools, such as:

 the influences of bather load on the instant DBP formation

 advanced treatment technologies, such as UV/H2O2, ozone could be investigated as potential options for swimming pool water treatment ,

 the efficiency of Advanced Oxidation Processes (AOPs), such as UV/H2O2 and ozone, on DBP formation in swimming pool water  the kinetics of DBP formation from PCP additives and BFA compounds

157 7.2 Operational suggestions

 High water replacement rate should be applied during occasional high bather load to minimize potentially harmful DBPs if financial condition allows.  Increased air circulation and ventilation in indoor swimming pools would be beneficial to the removal of volatile DBPs, such as THMs and some organic chloramines.  In order to minimize the formation of DBPs in swimming pools, it is critical to take sufficient and effective shower before entering the pool. On the contrary swimmers should put on sunscreen right after jumping out of swimming pool to avoid sunburn and skin cancer.  In addition, for children who play in swimming pools for extended periods of time, it should be recognized that none-dermal-penetrating DBPs, such as HAAs, could be ingested due to incidental swallowing of pool water. Therefore, it is recommended that parents take close care of them to minimize incidental swallowing.

158

Chapter 8 Reference

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Aggazzotti, G., Fantuzzi, G., Tartoni, P. L., and Predieri, G. (1990) Plasma chloroform concentrations in swimmers using indoor swimming pools. Archives of Environmental Health, 45(3), 175-179.

Aggazzotti, G., and Predieri, G. (1986) Survey of volatile halogenated organics (VHO) in Italy-levels of VHO in drinking waters, surface waters and swimming pools. Water Research, 20(8), 959-963.

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AWWARF. 2005. Factors affecting the formation of NDMA in water and occurrence. Denver, CO, American Water Works Association Research Foundation.

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170

Chapter 9 Appendix

Appendix

9.1 QA/QC protocol

9.1.1 Typical calibration curves and QC charts for organic

chloramine

2.5 y = 3E-08x + 0.004 R² = 0.9981 2.0

1.5

1.0 Concentration (mg/L) Concentration 0.5

0.0 0.00E+00 2.00E+07 4.00E+07 6.00E+07 8.00E+07 Peak area

Figure 9.1-1 Typical calibration curve for organic chloramine

171

0.25 mg/L 0.5 mg/L 1.0 mg/L 1.5 mg/L 2.0 mg/L 130

Feb 16 2010 110 Upper CL Upper WL

Average 90

Lower WL Lower CL Jan 14/25 Jan 26/29 Feb 01/03 2010 Feb 05 2010 April 09/13

Recovery percentage Recovery 70 2010 2010 2010

50 0 5 10 15 20 25 30 35

Figure 9.1-2 QC chart for organic chloramine of 0.25 to 2.0 mg/L

9.1.2 Typical calibration curves and QC charts for THMs

Chloroform BDCM 120 120 y = 848.82x + 0.7785 y = 116.97x + 0.6557

R² = 0.9944 g/L) R² = 0.9893 μ g/L) g/L) 90 90

60 60

30 30 Concentration ( Concentration ( Concentration 0 0 0 0.03 0.06 0.09 0.12 0.15 0 0.2 0.4 0.6 0.8 1 Peak area ratio Peak area ratio

CDBM Bromoform

120 120

y = 105.36x - 0.1033 y = 177.43x - 1.0499 R² = 0.9916 g/L) g/L) R² = 0.9967

90 g/L) 90

μ μ

60 60

30 30 Concentration ( Concentration 0 ( Concentration 0 0 0.25 0.5 0.75 1 0 0.15 0.3 0.45 0.6

Peak area ratio Peak area ratio

Figure 9.1-3 Typical calibration curves for THMs

172

20 ug/L 40,50,60 ug/L 80,100 ug/L 160

140

Feb 17 2010 April 26 2010 August 08 2010 Upper CL 120 Upper WL

100 Average

80 Lower WL Lower CL Recovery percentage Recovery Jan 25 2010 April 09 2010 May 14 2010 Dec 11 2010 60

40 0 5 10 15 20 25 30

Figure 9.1-4 QC chart for chloroform of 20 to 100 µg/L

20 ug/L 40,50,60 ug/L 80,100 ug/L 150

Feb 17 2010 April 26 2010 August 08 2010 130 Upper CL Upper WL 110 Average

90 Lower WL Lower CL

Recovery percentage Recovery 70 Jan 25 2010 April 09 2010 May 14 2010 Dec 11 2010

50 0 5 10 15 20 25 30

Figure 9.1-5 QC chart for BDCM of 20 to 100 µg/L

173

20 ug/L 40,50,60 ug/L 80,100 ug/L 160

140 Feb 17 2010 April 26 2010 August 08 2010 Upper CL Upper WL 120

Average 100

Lower WL 80 Lower CL

Recovery percentage Recovery Jan 25 2010 April 09 2010 May 14 2010 Dec 11 2010 60

40 0 5 10 15 20 25 30

Figure 9.1-6 QC chart for CDBM of 20 to 100 µg/L

20 ug/L 40,50,60 ug/L 80,100 ug/L 160

140 Feb 17 2010 April 26 2010 August 08 2010 Upper CL Upper WL 120 Average 100 Lower WL Lower CL 80

Jan 25 2010 April 09 2010 May 14 2010 Dec 11 2010 Recovery percentage Recovery 60

40 0 5 10 15 20 25 30

Figure 9.1-7 QC chart for bromoform of 20 to 100 µg/L

174

9.1.3 Typical calibration curves and QC charts for HAA9 MBAA MCAA 80

80 y = 71.628x + 0.6752

y = 940.71x + 1.4394 R² = 0.9882

R² = 0.9881 g/L) 60 g/L)

60 μ μ 40 40

20 Concentration ( Concentration

Concentration ( Concentration 0 0 0 0.25 0.5 0.75 1 0 0.02 0.04 0.06 0.08 Peak area ratio Peak area ratio

DCAA TCAA

80 80

y = 61.277x + 0.0011 y = 21.453x - 1.2732 g/L) g/L) R² = 0.9949 R² = 0.9948

μ μ 60 60

40 40

20 20 Concentration ( Concentration Concentration ( Concentration 0 0 0 0.3 0.6 0.9 1.2 0 0.6 1.2 1.8 2.4 3 Peak area ratio Peak area ratio BCAA DBAA

y = 28.274x - 1.0504 y = 25.77x - 1.6521 g/L)

R² = 0.996 g/L) R² = 0.9959 μ 60 μ 60

40 40

20 20

Concentration ( Concentration Concentration ( Concentration 0 0 0 0.6 1.2 1.8 2.4 0 0.6 1.2 1.8 2.4 3 Peak area ratio Peak area ratio

BDCAA CDBAA

y = 20.083x - 2.2984 y = 26.383x - 2.779 g/L)

g/L) R² = 0.994 R² = 0.9905 μ μ 60 60

40 40

20 20

Concentration ( Concentration Concentration ( Concentration 0 0 0 0.8 1.6 2.4 3.2 0 0.6 1.2 1.8 2.4 Peak area ratio Peak area ratio

175

TBAA 80 y = 32.292x - 1.5491

g/L) R² = 0.9928 μ 60

( Concentration 0 0 0.5 1 1.5 2 Peak area ratio

Figure 9.1-8 Typical calibration curve for HAAs

10,20,30 ug/L 40,50,60 ug/L 160

April 09 2010 May 14 2010 July 27 2010 Dec 02 2010

140 Upper CL Upper WL 120

Average 100

Lower WL Recovery percentage Recovery 80 Lower CL Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010 60 0 5 10 15 20 25 30

Figure 9.1-9 QC chart for MCAA of 10 to 60 µg/L

176

10,20,30 ug/L 40,50,60 ug/L 160

140 April 09 2010 May 14 2010 July 27 2010 Dec 02 2010 Upper CL Upper WL 120 Average

100 Lower WL Lower CL

Recovery percentage Recovery 80 Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010

60 0 5 10 15 20 25 30

Figure 9.1-10 QC chart for MBAA of 10 to 60 µg/L

10,20,30 ug/L 40,50,60 ug/L 160

April 09 2010 May 14 2010 July 27 2010 Dec 02 2010 140 Upper CL Upper WL 120 Average

100 Lower WL Lower CL

Recovery percentage Recovery 80 Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010

60 0 5 10 15 20 25 30

Figure 9.1-11 QC chart for DCAA of 10 to 60 µg/L

177

10,20,30 ug/L 40,50,60 ug/L 160 April 09 2010 May 14 2010 July 27 2010 Dec 02 2010

140 Upper CL Upper WL 120 Average

100 Lower WL Lower CL

Recovery percentage Recovery 80 Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010

60 0 5 10 15 20 25 30

Figure 9.1-12 QC chart for TCAA of 10 to 60 µg/L

10,20,30 ug/L 40,50,60 ug/L 160

April 09 2010 May 14 2010 July 27 2010 Dec 02 2010

140 Upper CL Upper WL 120 Average

100 Lower WL

Lower CL Recovery percentage Recovery 80 Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010

60 0 5 10 15 20 25 30

Figure 9.1-13 QC chart for BCAA of 10 to 60 µg/L

178

10,20,30 ug/L 40,50,60 ug/L 160 April 09 2010 May 14 2010 July 27 2010 Dec 02 2010

140 Upper CL Upper WL

120 Average

Lower WL 100 Lower CL

Recovery percentage Recovery 80 Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010

60 0 5 10 15 20 25 30

Figure 9.1-14 QC chart for DBAA of 10 to 60 µg/L

10,20,30 ug/L 40,50,60 ug/L 160

April 09 2010 May 14 2010 July 27 2010 Dec 02 2010

140 Upper CL Upper WL 120 Average

100 Lower WL Lower CL

Recovery percentage Recovery 80 Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010

60 0 5 10 15 20 25 30

Figure 9.1-15 QC chart for BDCAA of 10 to 60 µg/L

179

10,20,30 ug/L 40,50,60 ug/L 160

April 09 2010 May 14 2010 July 27 2010 Dec 02 2010

140 Upper CL Upper WL 120 Average

100 Lower WL

Lower CL Recovery percentage Recovery 80 Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010

60 0 5 10 15 20 25 30

Figure 9.1-16 QC chart for CDBAA of 10 to 60 µg/L

10,20,30 ug/L 40,50,60 ug/L 160

April 09 2010 May 14 2010 July 27 2010 Dec 02 2010

140 Upper CL Upper WL

120 Average

Lower WL 100 Lower CL

Recovery percentage Recovery 80 Feb 19 2010 Apr 29 2010 June 08 2010 Sep 03 2010

60 0 5 10 15 20 25 30

Figure 9.1-17 QC chart for TBAA of 10 to 60 µg/L

180

9.1.4 Typical calibration curves and QC charts for nitrosamines

NDMA NDBA

120 120

y = 62.008x - 3.2722 y = 153.18x + 3.3902 R² = 0.9992 R² = 0.9952 90 90

60 60

30 30 Concentration ng/L Concentration 0 ng/L Concentration 0 0 0.5 1 1.5 2 0 0.2 0.4 0.6 0.8 Peak area ratio Peak area ratio

NDEA NMEA

120

120 y = 42.246x + 3.8218 y = 33.63x + 2.6356 R² = 0.9957 R² = 0.9982 90 90

60 60

30 30 Concentration ng/L Concentration Concentrationng/L 0 0 0 1 2 3 0 1 2 3 4 Peak area ratio Peak area ratio

NMOR NPIP

120 120

y = 54.156x + 1.6758 y = 44.372x - 1.0395 R² = 0.9934 R² = 0.9838 90 90

60 60

30 30

Concentration ng/L Concentration 0 ng/L Concentration 0 0 0.5 1 1.5 2 0 1 2 3 Peak area ratio Peak area ratio

NPRO NPYR 120 120

y = 55.247x + 0.459 y = 46.226x + 3.66 R² = 0.9943 R² = 0.9924 90 90

60 60

30 30 Concentration ng/L Concentration Concentration ng/L Concentration 0 0 0 1 2 3 0 0.5 1 1.5 2 Peak area ratio Peak area ratio

Figure 9.1-18 Typical calibration curve for nitrosamines

181

10,20 ng/L 40,50 ng/L 80 ng/L 160

140 Jan 18 2010 Aug 16 2010 Apr 16 2010 Upper CL 120 Upper WL

100 Average

Lower WL

80 Lower CL Recovery percentage Recovery 60 Oct 11 2009 June 14 2010 Jan 31 2010 Dec 04 2010

40 0 5 10 15 20

Figure 9.1-19 QC chart for NDMA of 10 to 80 ng/L

10,20 ng/L 40,50 ng/L 80 ng/L 160 Jan 18 2010 Aug 16 2010 140 Apr 16 2010 Upper CL Upper WL 120

100 Average

80 Lower WL

Recovery percentage Recovery Lower CL 60 Oct 11 2009 June 14 2010 Jan 31 2010 Dec 04 2010 40 0 5 10 15 20

Figure 9.1-20 QC chart for NDBA of 10 to 80 ng/L

182

10,20 ng/L 40,50 ng/L 80 ng/L 170 Jan 18 2010 Aug 16 2010 150 Apr 16 2010 Upper CL 130 Upper WL

110 Average

90 Lower WL Lower CL 70 Oct 11 2009 June 14 2010 Recovery percentage Recovery Jan 31 2010 Dec 04 2010 50

30 0 5 10 15 20

Figure 9.1-21 QC chart for NDEA of 10 to 80 ng/L

10,20 ng/L 40,50 ng/L 80 ng/L 160

140 Jan 18 2010 Aug 16 2010 Apr 16 2010 Upper CL 120 Upper WL

100 Average

Lower WL

80 Lower CL Recovery percentage Recovery 60 Oct 11 2009 June 14 2010 Jan 31 2010 Dec 04 2010 40 0 5 10 15 20

Figure 9.1-22 QC chart for NMEA of 10 to 80 ng/L

183

10,20 ng/L 40,50 ng/L 80 ng/L 170

150 Jan 18 2010 Aug 16 2010

Apr 16 2010 130 Upper CL Upper WL 110 Average 90 Lower WL 70 Lower CL

Recovery percentage Recovery Oct 11 2009 June 14 2010 50 Jan 31 2010 Dec 04 2010

30 0 5 10 15 20

Figure 9.1-23 QC chart for NMOR of 10 to 80 ng/L

10,20 ng/L 40,50 ng/L 80 ng/L 150 Jan 18 2010 Aug 16 2010 Apr 16 2010 130 Upper CL Upper WL 110 Average 90 Lower WL Lower CL 70

Recovery percentage Recovery Oct 11 2009 June 14 2010 50 Jan 31 2010 Dec 04 2010

30 0 5 10 15 20

Figure 9.1-24 QC chart for NPIP of 10 to 80 ng/L

184

10,20 ng/L 40,50 ng/L 80 ng/L 170 Jan 18 2010 Aug 16 2010

150 Apr 16 2010

130 Upper CL Upper WL 110 Average 90 Lower WL

70 Lower CL Recovery percentage Recovery 50 Oct 11 2009 June 14 2010 Jan 31 2010 Dec 04 2010 30 0 5 10 15 20

Figure 9.1-25 QC chart for NPRO of 10 to 80 ng/L

10,20 ng/L 40,50 ng/L 80 ng/L 170

150 Jan 18 2010 Aug 16 2010

Apr 16 2010 130 Upper CL Upper WL 110 Average 90 Lower WL 70 Lower CL

Recovery percentage Recovery Oct 11 2009 June 14 2010 50 Jan 31 2010 Dec 04 2010

30 0 5 10 15 20

Figure 9.1-26 QC chart for NPYR of 10 to 80 ng/L

185 9.2 Raw data for additional swimming pools

Table 9.2-1 Measurements of on campus indoor swimming pool before shocking treatment (In1)

Sampling date January 05 2010(1) February 01 2010 April 09 2010 Approx. bather load 80 110 120 Free chlorine (mg/L) 1.75 1.35 1.80 Total chlorine (mg/L) 3.06 2.88 3.05 Monochloramine (mg/L) 0.03 0.06

HAA9 (µg/L) 224 185 310 NDMA (ng/L) 0.9 6.3 1.6 NDBA (ng/L)

186

Table 9.2-2 Measurements of on campus indoor swimming pool after shocking treatment (In 1)

January 05 2010 January 14 2010 January 25 2010 February 01 2010 April 09 2010 Sampling date (1 day after shocking (1 day after shocking (2 days after shocking (Right after shocking (Right after shocking treatment) treatment) treatment) treatment) treatment) Approx. bather load 80 90 100 110 120 Free chlorine (mg/L) 2.09 2.39 2.14 2.33 2.25 Total chlorine (mg/L) 6.70 3.83 3.79 6.70 6.25 Monochloramine (mg/L) 0.03 0.07 0.05 0.06

187

DBAA (µg/L) 6.6 1.8 17.3 0.89 11.4 BDCAA (µg/L)

HAA9 (µg/L) 218 355 345 167 336 NDMA (ng/L) 1.2 0.4 3.5 7.3 0.93 NDBA (ng/L)

188

Table 9.2-3 Measurements of on campus indoor swimming pool (In3)

January 14 January 25 February 01 April 09 Sampling date 2010 2010 2010 2010 Approx. bather load 40 40 70 50 Free chlorine (mg/L) 1.72 1.74 1.88 1.70 Total chlorine (mg/L) 2.26 2.43 2.50 2.25 Monochloramine (mg/L) 0.03 0.04 0.05

HAA9 (µg/L) 322 323 201 312 NDMA (ng/L) 1.7 5.95 8.74 1.02 NDBA (ng/L)

189

Table 9.2-4 Measurements of community indoor swimming pool (In5)

Sampling date April 26 2010 May 14 2010 Approx. bather load 110 90 Free chlorine (mg/L) 2.70 2.13 Total chlorine (mg/L) 3.50 3.15 Monochloramine (mg/L)

HAA9 (µg/L) 700 515 NDMA (ng/L)

190

Table 9.2-5 Measurements of outdoor swimming pool (Out2)

Sampling Date August 09 2010 August 12 2010 August 17 2010 Approx. bather load 400 450 500 Free chlorine (mg/L) 2.38 5.08 8.68 Total chlorine (mg/L) 2.63 5.48 9.10 Monochloramine (mg/L) 0.01 0.01 0.01 Free ammonia (mg/L)

HAA9 711 553 1080 NDMA (ng/L) 5.9 11.1 3.1 NDBA (ng/L) 35 110 360 NDEA (ng/L) 53

191 9.3 Additional data for free chlorine breakpoint testing of

individual BFA base mix compounds, PCP additives,

and cyanuric acid

Table 9.3-1 Breakpoint measurements for BFA compound #2 (urea) Mole ratio Initial free Free chlorine Total chlorine Cl:N chlorinedose (mg/L) residual (mg/L) residual (mg/L) 1:1 17.50 14.37 14.70 2:1 34.99 29.42 30.42 3:1 52.49 46.33 46.83 4:1 69.98 57.83 61.33 5:1 87.48 73.67 73.00 Concentration of BFA compound #2 (urea) was 14.8 mg/L with test time of 1.5 hours.

FCl TCl

20 Concentration (mg/L) Concentration 0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-1 Breakpoint curve for 14.8 mg/L BFA compound #2 (urea)

Table 9.3-2 Breakpoint measurements for BFA compound #4 (hippuric acid) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.68 0.69 0.71 2:1 1.36 1.23 1.34 3:1 2.03 1.82 1.93 4:1 2.71 2.56 2.48 5:1 3.39 3.03 3.13 Concentration of BFA compound #4 (hippuric acid) was 1.71 mg/L with test time of 1.5 hours.

192

FCl TCl

1 Concentration (mg/L) Concentration

0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-2Breakpoint curve for 1.71 mg/L BFA compound #4 (hippuric acid)

Table 9.3-3 Breakpoint measurements for BFA compound #5 (uric acid) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.21 0.03 0.03 2:1 0.41 0.03 0.08 3:1 0.62 0.09 0.19 4:1 0.83 0.24 0.37 5:1 1.04 0.40 0.53 Concentration of BFA compound #5 (uric acid) was 0.49 mg/L with test time of 3 hours.

FCl TCl

0.6

0.4

0.2 Concentration (mg/L) Concentration

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-3 Breakpoint curve for 0.49 mg/L BFA compound #5 (uric acid)

193

Table 9.3-4 Breakpoint measurements for BFA compound #6 (citric acid) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.24 0.24 0.26 2:1 0.47 0.40 0.47 3:1 0.71 0.64 0.68 4:1 0.95 0.81 0.83 5:1 1.18 1.12 1.18 Concentration of BFA compound #6 (citric acid) was 0.64 mg/L with test time of 1.25 hours.

FCl TCl

1.6

1.2

0.8

0.4 Concentration (mg/L) Concentration

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-4 Breakpoint curve for 0.64 mg/L BFA compound #6 (citric acid)

Table 9.3-5 Breakpoint measurements for PCP additive A2 (Padimate O) (2-ethylhexyl

4-dimethylamino benzoate) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.26 0.18 0.21 2:1 0.51 0.36 0.40 3:1 0.77 0.64 0.69 4:1 1.02 0.89 0.94 5:1 1.28 1.07 1.14 Concentration of PCP additive A2 (Padimate O) was 1 mg/L with test time of 2 hours.

194

FCl TCl

1.2

0.9

0.6

0.3 Concentration (mg/L) Concentration

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-5 Breakpoint curve for 1 mg/L PCP additive A 2 (Padimate O)

Table 9.3-6 Breakpoint measurements for PCP additive A 3 (nitrilotriacetic acid) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.37 0.35 0.37 2:1 0.74 0.61 0.66 3:1 1.11 0.93 0.97 4:1 1.49 1.28 1.37 5:1 1.86 1.65 1.73 Concentration of PCP additive A 3 (nitrilotriacetic acid) was 1 mg/L with test time of 1.5 hours.

FCl TCl

2.0

1.6

1.2

0.8

Concentration (mg/L) Concentration 0.4

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-6 Breakpoint curve for 1 mg/L PCP additive A 3 (nitrilotriacetic acid)

195

Table 9.3-7 Breakpoint measurements for PCP additive A 5 (tetrabutylammonium chloride) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.26 0.24 0.22 2:1 0.51 0.50 0.51 3:1 0.77 0.70 0.76 4:1 1.02 0.98 1.01 5:1 1.28 1.30 1.30 Concentration of PCP additive A 5 (tetrabutylammonium chloride) was 1 mg/L with test time of 1.25 hours.

FCl TCl

1.6

1.2

0.8

0.4 Concentration (mg/L) Concentration

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-7 Breakpoint curve for 1 mg/L PCP additive A 5 (tetrabutylammonium chloride)

Table 9.3-8 Breakpoint measurements for PCP additive A 6 (cetyltrimethylammonium chloride) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.22 0.20 0.18 2:1 0.44 0.45 0.40 3:1 0.67 0.62 0.65 4:1 0.89 0.77 0.82 5:1 1.11 0.86 1.03 Concentration of PCP additive A 6 (cetyltrimethylammonium chloride) was 1 mg/L with test time of 1.5 hours.

196

FCl TCl

1.2

0.9

0.6

0.3 Concentration (mg/L) Concentration

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-8 Breakpoint curve for 1 mg/L PCP additive A 6 (cetyltrimethylammonium chloride)

Table 9.3-9 Breakpoint measurements for PCP additive A 7 (choline chloride) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.51 0.55 0.54 2:1 1.01 1.01 1.07 3:1 1.52 1.50 1.62 4:1 2.02 1.81 2.05 5:1 2.53 2.28 2.51 Concentration of PCP additive A 7 (choline chloride) was 1 mg/L with test time of 1.25 hours.

FCl TCl

3.0

2.4

1.8

1.2

Concentration (mg/L) Concentration 0.6

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-9 Breakpoint curve for 1 mg/L PCP additive A 7 (choline chloride)

197

Table 9.3-10 Breakpoint measurements for PCP additive A 8 (cocamidopropyl betaine) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.21 0.19 0.21 2:1 0.41 0.37 0.41 3:1 0.62 0.58 0.63 4:1 0.83 0.78 0.81 5:1 1.04 0.93 1.01 Concentration of PCP additive A8 (cocamidopropyl betaine) was 1 mg/L with test time of 1.5 hours.

FCl TCl

1.2

0.9

0.6

Concentration (mg/L) Concentration 0.3

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-10 Breakpoint curve for 1 mg/L PCP additive A 8 (cocamidopropyl betaine)

Table 9.3-11 Breakpoint measurements for PCP additive A 9 (behentrimonium chloride) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.18 0.17 0.19 2:1 0.35 0.33 0.34 3:1 0.53 0.43 0.43 4:1 0.70 0.59 0.66 5:1 0.88 0.77 0.85 Concentration of PCP additive A 9 (behentrimonium chloride) was 1 mg/L with test time of 1.25 hours.

198

FCl TCl

0.9

0.8 0.7 0.6 0.5 0.4 0.3

Concentration (mg/L) Concentration 0.2 0.1 0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-11 Breakpoint curve for 1 mg/L PCP additive A 9 (behentrimonium chloride)

Table 9.3-12 Breakpoint measurements for PCP additive A10 (tetramethylammonium chloride) Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.65 0.59 0.68 2:1 1.30 1.13 1.33 3:1 1.94 1.87 1.95 4:1 2.59 2.35 2.44 5:1 3.24 2.89 3.04 Concentration of PCP additive A10 (tetramethylammonium chloride) was 1 mg/L with test time of 1.5 hours.

FCl TCl

3.5

2.8

2.1

1.4

Concentration (mg/L) Concentration 0.7

0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-12 Breakpoint curve for 1 mg/L PCP additive A 10 (tetramethylammonium chloride)

199

Table 9.3-13 Breakpoint measurements for cyanuric acid Mole ratio Initial free chlorine Free chlorine Total chlorine Cl:N dose (mg/L) residual (mg/L) residual (mg/L) 1:1 0.55 0.46 0.46 2:1 1.10 0.89 1.01 3:1 1.65 1.29 1.48 4:1 2.20 1.93 2.02 5:1 2.75 2.41 2.56 Concentration of cyanuric acid was 1 mg/L with test time of 1.5 hours.

FCl TCl

3.0

2.4

1.8

1.2

0.6 Concentration (mg/L) Concentration 0.0 0 1 2 3 4 5 6 Cl:N mole ratio

Figure 9.3-13 Breakpoint curve for 1 mg/L cyanuric acid

200 9.4 Results of t-tests for experiments in Chapter 5

This part includes the results of the significance t-test for Part III and Part IV, which examined the influence of BFA compounds and PCP additives on DBP formation in outdoor swimming pool (Out3) water and indoor swimming pool (In2) water. Results for compounds of significance are indicated as a Y and compounds of insignificance are indicated as an N.

Table 9.4-1 Summary of total student t-test for experiment results from Out3 pool water spiked

with BFAs, PCPs, cyanuric acid and humic acid

p-value Yes p-value Yes p-value Yes p-value Yes Compounds for or for or for or for or ID THMs Not HAA9 Not NDEA Not NDBA Not #2 0.1512 N 0.2542 N 0.2587 N 0.0004 Y #3 0.9532 N 0.4956 N 0.0938 N 0.0016 Y BFA #4 0.8288 N 0.0111 Y 0.0866 N 0.5060 N Compound #5 0.0394 Y 0.0420 Y 0.8786 N 0.0014 Y #6 0.0047 Y 0.1365 N 0.3889 N 0.0053 Y #7 0.0694 N 0.3102 N 0.5022 N 0.0021 Y A1 0.1444 N 0.2306 N 0.0454 Y 0.0003 Y A2 0.2073 N 0.1088 N 0.5406 N 0.0021 Y A3 0.9020 N 0.1784 N 0.0689 N 0.0290 Y PCP A4 0.0007 Y 0.8802 N 0.8867 N 0.0026 Y A5 0.1769 N 0.4029 N 0.6233 N 0.0019 Y A6 0.0005 Y 0.7552 N 0.8222 N 0.0034 Y Additive A7 0.0088 Y 0.2786 N 0.0061 Y 0.0108 Y A8 0.0021 Y 0.6106 N 0.0032 Y 0.0161 Y A9 0.0030 Y 0.7185 N 0.5705 N 0.0125 Y A10 0.2146 N 0.6690 N 0.0563 N 0.0523 N Cyanuric acid 0.1636 N 0.1969 N 0.2246 N 0.5854 N Humic acid 0.0350 Y 0.7822 N 0.0970 N 0.2024 N Note: Ymeans the influence of the additive on formation of the DBP is significant, N means no significant influence.

201

BFA compounds include #2 (Urea), #3 (Histidine), #4 (Hippuric acid), #5 (Uric acid),

#6 (Citric acid), #7 (Creatinine). PCP additives include A1 (Diethanolamine), A2

(Padimate O), A3 (Nitrilotriacetic acid), A4 (Triehanolamine), A5

(Tetrabutylammonium chloride), A6 (Cetyltrimethylammonium chloride), A7 (Choline chloride), A8 (Cocamidopropyl betaine), A9 (Behentrimonium chloride), A10

(Tetramethylammonium chloride). Swimming pool stabilizer (cyanuric acid) and humic acid are also included.

Table 9.4-2 Summary of total student t-test for experiment results from In2 pool water spiked with

BFAs, PCPs, cyanuric acid and humic acid

p-value Yes p-value Yes p-value Yes p-value Yes Compounds for or for or for or for or ID THMs Not HAA9 Not NDMA Not NMOR Not #2 0.2742 N 0.7441 N 0.6341 N 0.0021 Y #3 0.0211 Y 0.0412 Y 0.2713 N 0.1939 N BFA #4 0.0638 N 0.9781 N 0.3800 N 0.3828 N Compound #5 0.0252 Y 0.5681 N 0.0023 Y 0.0001 Y #6 0.0831 N 0.5472 N 0.0009 Y 0.0082 Y #7 0.0291 Y 0.9082 N 0.0730 N 0.0028 Y A1 0.0247 Y 0.0183 Y 0.3997 N 0.0080 Y A2 0.0240 Y 0.0073 Y 0.0008 Y 0.0051 Y A3 0.0004 Y 0.0258 Y 0.0885 N 0.3224 N PCP A4 0.1211 N 0.0043 Y 0.0007 Y 0.9037 N A5 0.0000 Y 0.0077 Y 0.0911 N 0.1794 N A6 0.2496 N 0.0073 Y 0.5837 N 0.0014 Y Additive A7 0.0002 Y 0.0627 N 0.5671 N 0.0751 N A8 0.0000 Y 0.0096 Y 0.0459 Y 0.4688 N A9 0.0079 Y 0.0069 Y 0.0014 Y 0.8554 N A10 0.0000 N 0.0036 Y 0.7486 N 0.2656 N Cyanuric acid 0.8413 N 0.0055 Y 0.0009 Y 0.0003 Y Humic acid 0.0002 Y 0.0063 Y 0.3588 N 0.0107 Y Note: Y means the influence of the additive on formation of the DBP is significant, N means no significant influence. NDEA results are not included since the results are obviously significant except for BFA #2 (p-value = 0.2162; N) and cyanuric acid (p-value = 0.2503; N).