A Comparison Between Freshwater and Seawater Swimming Pools: From Chemical Profile to Genotoxicity

Transcription

1 A Comparison Between Freshwater and Seawater Swimming Pools: From Chemical Profile to Genotoxicity Tarek Manasfi a, Michel De Meo b, Bruno Coulomb a, Carole Di Giorgio b, Jean-Luc Boudenne a a Environmental Chemistry Laboratory b Environmental Mutagenesis Laboratory Aix-Marseille University, France 1

2 Why interested in seawater pools Among studies about swimming pools, only few have looked at the occurrence of DBPs in seawater pools In seawater pools, brominated DBPs are expected to be formed, known to be more toxic than chlorinated ones 2

3 Thalassotherapy, at a Glance Seawater pools can be found in thalassotherapy centers, an emerging and rapidly growing sector Formerly limited to patients, nowadays attendees are not only curists but also mere tourism and wellness seekers Attendees expect wellbeing and beneficial health effects so the question of chemical safety remains a concern (Schwartz, 2005; Johnston et al., 2011) 3

4 Pools Characteristics: Seawater Vs. Freshwater Seawater Pools (thalasso) Mainly indoor Natural seawater ph = Disinfection: HOCl HOCl/OCl - + Br - HOBr/OBr - + Cl - Brominated DBPs, more toxic Temperature: ᵒC Freshwater Pools Indoor or outdoor Tap/freshwater ph = 7 Disinfection: HOCl Chlorinated DBPs Temperature: ᵒC 4

5 Objectives of Study Determine DBP contents in seawater swimming pools and compare them to a reference freshwater pool Assess the genotoxic properties of pool water concentrates/extracts Relate genotoxicity results to the DBP chemical composition 5

6 Study Site Four swimming pools in two establishments (E1 and E2) located in Southeast France Establishment E1 Indoor seawater Outdoor freshwater Establishment E2 Two indoor Seawater pools Pre-filtration on sand Disinfection with Bleach 6

7 Methodology Sampling On-site measurements Laboratory measurements 7

8 Methodology Sampling On-site measurements Laboratory measurements Temperature, ph, turbidity, salinity Free chlorine, total chlorine 8

9 Methodology Sampling On-site measurements Laboratory measurements Temperature, ph, turbidity, salinity Free chlorine, total chlorine TOC and DBPs (THM, HAA, HAN, HK, THA) Genotoxicity assessment (Ames test) Samples conserved at 4 C till treatment 9

10 Treatment of Samples in Laboratory Sample Analysis in triplicates DBP Analysis Genotoxicity Assay Acidification and LLE (MTBE) With or without derivatization Addition of IS Injection GC-ECD 10

11 Treatment of Samples in Laboratory Sample Analysis in triplicates DBPs Analysis Genotoxicity Assay Acidification and LLE (MTBE) With or without derivatization Addition of IS Injection GC-ECD Resin Extraction: XAD-8/XAD-2 in a column Eluant ethyl acetate Solvent Exchange (DMSO) Concentrate x 20,000 Ames test ± S9 fraction 11

12 Results Global Parameters Freshwater Pool E1 Seawater Pool E1 Seawater Pool E2 (1) Seawater Pool E2 (2) T ( C) ph Salinity (PSU) TOC (mg C/L) Free Chlorine (mg/l) TOC levels were of the same order in all the pools However, freshwater pool was remarkably more frequented Freshwater pool was outdoors higher volatilization 12

13 Results Analysis of DBPs THM HAA HAN HK THA 13

14 THM concentration (µg/l) Results: Analysis of DBPs Trihalomethanes (THMs) Major THM: Chloroform in freshwater pool Vs. Bromoform in seawater pools 14

15 Results: Analysis of DBPs Haloacetic acids (HAAs) 5% HAA-9 = µg/l 92% HAA-9 = µg/l 40% 54% HAA-9 = µg/l 36% 33% 58% HAA-9 = µg/l 59% Major HAA: Trichloroacetic acid in Freshwater Vs. Dibromoacetic acid in seawater 15

16 HAN concentration (µg/l) Results: Analysis of DBPs Haloacetonitriles (HANs) Major HAN: DCAN in freshwater pool Vs. DBAN in seawater pool 16

17 THA Concentration (µg/l) (log scale) Results: Analysis of DBPs Trihaloacetaldehydes (THA) Levels of chloral hydrate in the freshwater pool are far higher than the levels of bromal hydrate in seawater pools 17

18 Results: Analysis of DBPs DBPs: Freshwater Vs. Seawater Pools Main DBP classes: HAAs the most abundant in all pools followed by trihaloacetaldehydes in freshwater pool and THMs in seawater pools 18

19 DBPs concentration (µg/l) Results: Analysis of DBPs DBPs: Freshwater Vs. Seawater Pools Higher DBP content in freshwater pool than in seawater pools Frequentation rates difference seems responsible 19

20 Origin of found DBPs Are the found DBPs from natural organic matter or anthropogenic origins? 1- Levels of HAAs and HANs suggest the implication of anthropogenic organic matter! 2- Pre-filtration of water is supposed to eliminate to a large extent the NOM present in source water 20

21 Results: Genotoxicity (Ames Test) Freshwater samples Mutagenic Potencies Seawater samples Without S9 mix: 3.7 rev/ml-eq 0.4 rev/ml-eq With S9 mix: 1.8 rev/ml-eq 0.3 rev/ml-eq 21

22 Results: Genotoxicity (Ames Test) Dose-Response Relationships (without S9 mix) Water samples from the freshwater pool E1 were significantly more mutagenic than those from seawater pool E1 22

23 Conclusion: DBPs Most DBPs in the freshwater pool were chlorinated Vs. mostly brominated DBPs in the seawater pools Levels of bromal hydrate in thalassotherapy seawater pools were reported for the first time Trihaloacetaldehyde levels discrepancy between freshwater and seawater pools (instability at high ph) In the seawater pools (ph ~ 8.3): total HAN < THM-4 In the freshwater pool (ph ~ 7.0): total HAN THM-4 23

24 Conclusion: Genotoxicity Freshwater samples were more mutagenic than seawater samples, this seems to be related to the high DBP content Although brominated DBPs are known to be more genotoxic than chlorinated DBPs, the overall mixture effect seems more important than individual effects High frequentation rates seems responsible for high content in DBPs, which in turn seems responsible for the mutagenic properties 24

25 Perspectives Further research into the chemistry of swimming pool waters to determine the unknown DBPs Identification of the DBP fractions and classes contributing mainly to the observed mutagenicity and their routes of exposure Examination of other potential health effects of DBPs 25

26 Perspectives Identification of the anthropogenic loads (body fluids, PCPs ) that largely contribute to the formation of DBPs Efforts to reduce DBPs: educating the public about importance of hygiene measures, (stricter) regulations 26

27 Thank you! 27