Supplementary Data for

Occurrence and human exposure of parabens and their chlorinated derivatives in swimming pools

Wenhui Li a, Yali Shi b, Lihong Gao a, Jiemin Liu a,*, Yaqi Cai b,*

aSchool of Chemistry and Biological Engineering, University of Science and Technology Beijing, University of Science and Technology Beijing, Beijing 100083, China;

bState Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China

*Corresponding author

Tel: +86 10 62849182; fax: +86 10 62849182;E-mail:

Tel.: +86 010 62333751; E-mail:


Parameters are calculated according Exposure Factors Handbook (US EPA, 2011)

The permeability coefficient of parabens (Kp, cm h-1) was calculated using the equation:

logKp=-2.80+0.66logKow-0.0056 MW (1)

where Kp is the dermal permeability coefficient of parabens in water (cm h-1) ; Kow is the Octanol/water partition coefficient of the parabens (dimensionless) ; MW is the molecular weight (g mol-1)

The dimensionless ratio of the permeability coefficient of a compound through the stratum corneum relative to its permeability coefficient across the viable epidermis (B, dimensionless) was calculated using the equation:

B=KpMW2.6 (as an approximation) (2)

The effective diffusion coefficient (DSC, cm2 h-1) of the chemical in the stratum corneum was calculated using the equation:

log⁡(Dsclsc)=-2.80-0.0056 MW (3)

where lsc is the Apparent thickness of stratum corneum (cm), and lsc = 0.001 cm.

The lag time (τ, h) was calculated using the equation:

τ=lsc2∖(6Dsc)=0.105×10(0.0056 MW) (4)

Captions:

Table S1 Physicochemical characteristics of the target compounds

Table S2 Details of pool design and operating parameter values

Table S3 Experimental conditions of electrospray tandem mass spectrometry

Table S4 Correlation coefficients (r), linear range, recoveries (%) and method detection limits (MDLs, S/N=3) of target compounds

Table S5 Spearman's coefficients of the concentrations of target compounds and with operating parameters of 39 pools.

Fig.S1. Box-and-whisker plots of concentrations of parabens and chlorinated derivatives in indoor and outdoor swimming pools

Fig.S2. Box-and-whisker plots of concentrations of parabens and chlorinated derivatives on the weekend and weekdays.


Table S1 Physicochemical characteristics of the target parabens

Analytes / Structure / MW
(g mo1-1) / SW
(mg L-1) / pKa / logKow / Hc
(atm m3 mol-1)
p-Hydroxybenzoic acid (PHBA) / / 138.12 / 14,500 / 2.7; 8.4 / 1.39[1] / 1.13×10-11 [2]
Methyl paraben (MeP) / / 152.15 / 5981 / 8.17[3] / 1.66[3] / 3.61×10-9
Ethyl paraben
(EtP) / / 166.17 / 960[4] / 8.22 / 2.19 / 4.79×10-9
Propyl paraben
(PrP) / / 180.20 / 390[4] / 8.35 / 2.71 / 6.37×10-9
Butyl paraben
(BuP) / / 194.23 / 207[5] / 8.37 / 3.24[4] / 8.45×10-9
Pentyl Paraben
(PeP) / / 208.25 / n.a. / n.a. / 3.48 / n.a.
Heptyl paraben
(HeP) / / 236.31 / n.a. / n.a. / 4.41 / 1.98×10-8
Benzyl paraben
(BzP) / / 228.24 / 160[5] / 8.18[6] / 3.56 [3] / 2.92×10-10
Octyl paraben
(OcP) / / 250.34 / n.a. / n.a. / 4.88 / n.a.
Methyl 3-chloro-4-hydroxybenzoate (3-Cl-MeP) / / 186.59 / 2.64[7] / n.a. / 2.27 / n.a.
Methyl 3,5-dichloro-4-hydroxybenzoate (3,5-2Cl-MeP) / / 221.04 / 3.29[7] / n.a. / 2.88 / n.a.
Ethyl 3-chloro-4-hydroxybenzoate (3-Cl-EtP) / / 200.62 / 2.31[8] / n.a. / n.a. / n.a.
Ethyl 3,5-dichloro-4-hydroxybenzoate (3,5-2Cl-EtP) / / 235.06 / 2.34[8] / n.a. / 3.32 / n.a.

The table includes information on the hydrophobicity (log Kow); aqueous solubility (Sw) at neutral pH; acid-base reactivity (pKa); Henry’s Law constant (Hc) at 25 °C. n.a.: not available

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Table S2 Details of pool design and operating parameter values

NO. / Type / Functional areas / Disinfection type / Size (m3) / Date / Opening Hours (h) / Price (RMB) / Visitors / TOC (mg L-1)
S01 / Indoor / Community / Chlorine / 500 / Weekday / 11 / 40 / 25 / 15.4
S02 / Indoor / Community / Chlorine / 600 / Weekend / 10 / 35 / 25 / 10.2
S03 / Indoor / School / Chlorine / 1200 / Weekday / 13 / 30 / 80 / 3.13
S04 / Indoor / School / Chlorine / 1700 / Weekend / 11 / 30 / 112 / 5.88
S05 / Indoor / School / Chlorine / 1200 / Weekday / 13.5 / 30 / 45 / 12.5
S06 / Indoor / School / Chlorine / 1200 / Weekend / 10 / 20 / 37 / 4.37
S07 / Indoor / School / Ozone/ Chlorine / 2000 / Weekday / 9.5 / 20 / 62 / 1.55
S08 / Indoor / Municipal / Chlorine / 1600 / Weekend / 10 / 50 / 192 / 9.50
S09 / Indoor / School / Chlorine / 400 / Weekday / 11 / 30 / 13 / 1.63
S10 / Indoor / School / Chlorine / 1600 / Weekend / 10 / 30 / 30 / 7.92
S11 / Indoor / Municipal / Ozone/ Chlorine / 600 / Weekend / 11 / 35 / 213 / 7.16
S12 / Indoor / Community / Chlorine / 480 / Weekend / 12 / 50 / 73 / 8.92
S13 / Indoor / Community / Chlorine / 400 / Weekday / 11 / 38 / 35 / 10.4
S14 / Indoor / Community / Chlorine / 300 / Weekend / 12 / 30 / 57 / 13.8
S15 / Indoor / Community / Chlorine / 400 / Weekday / 14 / 40 / 12 / 5.67
S16 / Indoor / Municipal / Chlorine / 600 / Weekend / 12 / 30 / 43 / 8.79
S17 / Outdoor / Municipal / Chlorine / 12000 / Weekend / 7 / 30 / 472 / 3.48
S18 / Outdoor / Municipal / Chlorine / 18000 / Weekday / 10 / 30 / 150 / 4.48
S19 / Outdoor / Municipal / Chlorine / 2400 / Weekday / 7.5 / 30 / 134 / 2.66
S20 / Indoor / Health club / Chlorine / 450 / Weekend / 13 / 35 / 28 / 11.9
S21 / Indoor / School / Chlorine / 400 / Weekend / 16 / 20 / 55 / 7.72
S22 / Indoor / School / Chlorine / 2000 / Weekend / 12 / 25 / 156 / 4.12
S23 / Indoor / School / Chlorine / 2250 / Weekend / 11.5 / 30 / 104 / 3.27
S24 / Indoor / Community / Chlorine / 1200 / Weekend / 14 / 40 / 17 / 6.88
S25 / Indoor / School / Chlorine / 2000 / Weekday / 12.5 / 50 / 76 / 7.94
S26 / Indoor / School / Chlorine / 2000 / Weekday / 12 / 50 / 46 / 7.66
S27 / Indoor / School / Chlorine / 2000 / Weekend / 12 / 50 / 74 / 6.69
S28 / Indoor / Municipal / Chlorine / 1600 / Weekend / 11 / 50 / 205 / 4.67
S29 / Indoor / Hotel / Chlorine / 3200 / Weekday / 12 / 100 / 1000 / 12.5
S30 / Indoor / Hotel / Chlorine / 240 / Weekday / 12 / 100 / 102 / 2.15
S31 / Indoor / Hotel / Chlorine / 160 / Weekend / 13 / 100 / 23 / 8.06
S32 / Indoor / Hotel / Chlorine / 500 / Weekend / 13 / 90 / 44 / 10.1
S33 / Indoor / Community / Chlorine / 600 / Weekend / 13 / 60 / 13 / 8.80
S34 / Indoor / Health club / Chlorine / 400 / Weekday / 12 / 40 / 12 / 9.83
S35 / Indoor / Health club / Chlorine / 1200 / Weekend / 12.5 / 50 / 121 / 10.6
S36 / Indoor / Community / Chlorine / 500 / Weekend / 12 / 40 / 23 / 10.0
S37 / Indoor / Municipal / Chlorine / 2000 / Weekend / 12 / 50 / 243 / 13.7
S38 / Outdoor / Municipal / Chlorine / 1600 / Weekend / 8 / 20 / 1131 / 12.9
S39 / Indoor / Health club / Chlorine / 600 / Weekend / 12 / 50 / 13 / 21.7

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Table S3 Experimental conditions of electrospray tandem mass spectrometry

Analytes / Parent
ion
(m/z) / Daughter
ion
(m/z) / Declustering
Potential/
V / Entrance
Potential/
V / Collision cellent potential/V / Collision
Energy/
eV / Collision cell
exit potential/
V
MeP / 151.0 / 91.9a
136.0 / -27
-27 / -5
-5 / -7
-6 / -26
-27 / -10
-14
EtP / 165.0 / 93.0 a
137.0 / -25
-25 / -5
-5 / -14
-7 / -30
-17 / -10
-13
PrP / 179.0 / 93.0
136.0 a / -30
-30 / -5
-5 / -8
-6 / -28
-20 / -10
-14
BuP / 193.0 / 91.9 a
136.0 / -30
-30 / -5
-5 / -8
-8 / -35
-21 / -10
-13
PeP / 207.1 / 91.9 a
93.0 / -35
-35 / -10
-10 / -9
-9 / -34
-30 / -10
-10
HeP / 235.1 / 92.0 a
135.9 / -40
-40 / -5
-5 / -12
-8 / -38
-25 / -10
-14
BzP / 227.0 / 91.9
136.0 a / -25
-25 / -5
-5 / -8
-8 / -34
-18 / -10
-14
OcP / 249.1 / 93.0 a
136.0 / -45
-45 / -5
-5 / -10
-10 / -35
-27 / -13
-10
PHBA / 137.0 / 93.0 a
65.1 / -23
-23 / -5
-5 / -8
-8 / -20
-43 / -10
-8
3-Cl-MeP / 185.0 / 126.0 a
142.0 / -30
-30 / -5
-5 / -7
-7 / -26
-24 / -13
-14
3,5-2Cl-MeP / 218.9 / 160.0 a
176.0 / -40
-35 / -5
-5 / -8
-8 / -28
-28 / -15
-15
3-Cl-EtP / 199.0 / 127.0
170.9 a / -32
-32 / -5
-5 / -8
-7 / -26
-20 / -13
-15
3,5-2Cl-EtP / 232.9 / 161.1 a
205.0 / -36
-36 / -5
-5 / -8
-8 / -30
-22 / -16
-18
PHBA-d4 / 141.0 / 97.1 a / -23 / -5 / -8 / -18 / -10
69.1 / -23 / -7 / -15 / -40 / -10
MeP-d4 / 155.0 / 96.1 a / -25 / -10 / -10 / -28 / -10
112.1 / -25 / -10 / -10 / -28 / -10
EtP-d5 / 170.0 / 91.9 / -26 / -5 / -8 / -30 / -10
94.0 a / -26 / -5 / -8 / -30 / -10
PrP-d7 / 186.1 / 91.9 / -30 / -5 / -8 / -33 / -10
94.0 a / -30 / -5 / -8 / -33 / -10
BuP-d9 / 202.1 / 91.9 a / -30 / -5 / -8 / -34 / -10
136.0 / -30 / -5 / -8 / -35 / -10
BzP-d7 / 233.9 / 91.9 / -40 / -9 / -10 / -40 / -11
136.0 a / -40 / -9 / -26 / -22 / -13

a quantitative ion


Table S4 Correlation coefficients (r2), linear range, recoveries (%) and method detection limits (MDLs, S/N=3) of target compounds

Analytes / Surrogates / r2 / Linear range (μg L-1) / Recovery (%) / MDLs (ng L-1)
MeP / MeP-d4 / 0.9997 / 0.1-500 / 97.5±7.4 / 0.07
EtP / EtP-d5 / 0.9987 / 0.1-500 / 92.7±5.1 / 0.03
PrP / PrP-d7 / 0.9993 / 0.1-500 / 94.3±5.7 / 0.08
BuP / BuP-d9 / 0.9998 / 0.05-200 / 94.4±6.9 / 0.03
Pep / BuP-d9 / 0.9984 / 0.05-500 / 97.6±3.8 / 0.03
Bzp / BzP-d7 / 0.9923 / 0.05-200 / 104±1.9 / 0.02
Hep / BuP-d9 / 0.9992 / 0.05-500 / 92.4±3.3 / 0.02
Ocp / BuP-d9 / 0.9995 / 0.1-200 / 94.2±5.9 / 0.06
PHBA / PHBA-d4 / 0.9907 / 1.0-500 / 85.9±11 / 0.40
3-Cl-MeP / MeP-d4 / 0.9998 / 0.1-500 / 101±4.3 / 0.07
3,5-2Cl-MeP / MeP-d4 / 0.9995 / 0.1-500 / 98.3±2.7 / 0.05
3-Cl-EtP / EtP-d5 / 0.9996 / 0.1-500 / 95.0±5.3 / 0.10
3,5-2Cl-EtP / EtP-d5 / 0.9996 / 0.1-500 / 101±5.6 / 0.16

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Table S5 Pearson's coefficients of the concentrations of target compounds and with parameters of 39 pools

Parameters / ∑PBs / ∑Cl-PBs / PHBA / ∑PBs+∑Cl-PBs
Pearson Correlation / Sig. (2-tailed) / Pearson Correlation / Sig. (2-tailed) / Pearson Correlation / Sig. (2-tailed) / Pearson Correlation / Sig. (2-tailed)
Price (RMB) / 0.336* / 0.036 / 0.037 / 0.825 / -0.229 / 0.160 / 0.326* / 0.042
Vistors / -0.083 / 0.617 / -0.301 / 0.062 / 0.067 / 0.683 / -0.093 / 0.573
Size (m3) / -0.116 / 0.480 / -0.350* / 0.029 / -0.091 / 0.583 / -0.128 / 0.436
Opening Hours (h) / 0.210 / 0.200 / 0.327* / 0.042 / 0.077 / 0.642 / 0.220 / 0.178
TOC (mg L-1) / 0.217 / 0.185 / 0.471** / 0.002 / 0.118 / 0.475 / 0.237 / 0.147

**. Correlation is significant at the 0.01 level (2-tailed); *. Correlation is significant at the 0.05 level (2-tailed)

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Fig.S1. Box-and-whisker plots of concentrations of parabens and chlorinated derivatives in indoor and outdoor swimming pools.


Fig.S2. Box-and-whisker plots of concentrations of parabens and chlorinated derivatives on the weekend and weekdays.

Reference

[1] Wang L, Kannan K. Alkyl protocatechuates as novel urinary biomarkers of exposure to p-hydroxybenzoic acid esters (parabens). Environ. Int., 2013, 59 27-32

[2] Wang L, Liao C Y, Liu F, et al. Occurrence and Human Exposure of p-Hydroxybenzoic Acid Esters (Parabens), Bisphenol A Diglycidyl Ether (BADGE), and Their Hydrolysis Products in Indoor Dust from the United States and Three East Asian Countries. Environ. Sci. Technol., 2012, 46 (21): 11584-11593