Candace Rowell (Doha, Qatar), Nora Kuiper 1, Hugues Preud'Homme 1, Basem Shomar 1
Qatar Environment and Energy Research Institute, Qatar Foundation1
Background: The potential introduction of trace contaminants through distribution networks, containers and storage conditions is a critical risk area for global water security. In the State of Qatar where expensive desalination technologies are used to provide high quality drinking water, the potential deterioration in quality due to these conditions within an extreme environment is of acute importance. This study investigated the leaching potential of bottled water containers for the full suite of trace elements and Bisphenol A (BPA), to determine leaching kinetics and mixture effects under UV radiation and heat stressors. Methods/Materials: A full trace element scan was performed on 110 bottled water samples using a Bruker Aurora Elite inductively couple plasma mass spectrometry (ICPMS). BPA was analyzed using a Bruker Impact HD ESI-QTOF. Samples were analyzed at time of purchase, after 1, 2 and 12 days of direct sun exposure and after 4 hours at 70C. The sample set was composed of 66 unique bottle brands of polycarbonate (n=1), glass (n=25) and polyethylene terephthalate (PET) (n=40) materials and included the available size denominations (300mL, 500mL, 750mL, 1L, 1.5L, 18.9L) for each brand to determine the relative impact of each container under each condition. The impact of varying water composition on container leaching was controlled for using the original bottled water, reference tap water and synthetic water of known composition. Synthetic water was also used to control for potential matrix effects. Results and Discussion: Initial results indicate significant leaching of Sb from PET containers under high heat. UV exposure also resulted in an increase of Sb, although the impact is notably less. Similar results were observed for samples that were (1) exposed to 70C for 4 hours in a laboratory oven or (2) stored in a vehicle for 2 weeks with an average daily outdoor temperature of 45C. The average Sb concentration at time of purchase was 0.220 ppb, after heat exposure, Sb concentrations were observed as high as 2.00 ppb. This trend was also observed for glass bottles; increased amounts of Pb, B and Sn were detected in samples stored under high temperature conditions. Interestingly, no considerable increase in trace element content was observed in the polycarbonate container (18.9L) which is commonly used as a primary drinking water source in Qatar. Pb and B are constituents of glass and therefore expected leachates; the source of Sn is under investigation. Sb is present in PET drinking water bottles due to the use of antimony trioxide (Sb2O3) as a catalyst in the manufacturing process. Previous works have shown considerable Sb leaching from PET storage containers into consumer water after prolonged storage times (6 months) (Shotyk and Krachler, 2007; Westerhoff et al. 2008). This study indicates heat is a primary driver for leachate kinetics of trace elements from storage containers with less effect from UV radiation. The mechanisms of degradation from UV exposure are currently being investigated. The results are being further investigated to explore leachate kinetics, mixture effects, effects of exposure to multiple stressors and the impact of these stressors for the full suite of trace elements (Be, Mo, B, Ag, Cd, Sb, Ba, Tl, Pb, Th, U, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Se, Li, C, Ne, Y, Zr, Nb, Tc, Ru, Rh, Pd, Ag, In, Sn, Te, I, Xe, Cs, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Po, Ra, Ac, Pa, Np, Pu, Mg, Si, P, S, Cl, K, Ca, Sc, Ti, Ge, Kr and Br), many of which are often ignored in these studies. Analysis of BPA content is currently on-going. The deterioration of bottled water quality under these conditions is an important global health concern as bottled water consumption continues to gain popularity. Conclusion: Prolonged exposure to high temperatures and UV radiation increases the potential of contaminant leachate in PET and glass drinking water bottles. Exposure to high temperatures (70C) for 4 hours in a laboratory oven and prolonged vehicle storage under high summer temperatures resulted in increased leaching of Sb in PET containers. Pb, Sn and B leaching was observed in glass containers under the same conditions. Direct exposure to UV radiation for a period of 12 days showed a limited increased in leachate kinetics, indicating heat to be a more significant risk factor. The introduction of toxic elements into drinking water is a critical health concern. Results indicate that typical storage conditions, both industrial and personal, may pose a significant threat to bottled water quality. Furthermore, the common used of solar water disinfection (SODIS) techniques may inadvertently introduce toxicants into drinking water. This study is exploring leachate kinetics, mixture effects and compound stressor effects for the full suite of trace elements and BPA. 1. Shotyk, W. and Krachler, M. (2007) Contamination of bottled waters with antimony leaching from polyethylene terephthalate (PET) increases upon storage. Environ. Sci. Tehnol. 41, 1560-1563. 2. Westerhoff, P. Prapaipong, P. Shock, E. and Hillaireau, A. (2008) Antimony leaching from polyethylene terephthalate (PET) plastic used for bottled drinking water. Water Res. 42, 551-556.