Environ. Sci. Technol. 2009, 43, 4824–4829
Perfluorinated Compounds in Tap Water from China and Several Other Countries Y I M L I N G M A K , †,‡ S A C H I T A N I Y A S U , ‡ L E O W . Y . Y E U N G , †,‡ G U O H U I L U , § LING JIN,† YONGLIANG YANG,§ P A U L K . S . L A M , †,* KURUNTHACHALAM KANNAN,⊥ AND N O B U Y O S H I Y A M A S H I T A ‡,* Centre for Coastal Pollution and Conservation, Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, People’s Republic of China, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan, National Research Center for Geoanalysis, Chinese Academy of Geological Sciences, 26 Bai Wan Zhuang Avenue, Xicheng District, Beijing, People’s Republic of China 100037, and Wadsworth Center, New York State Department of Health and Department of Environmental Health Sciences, State University of New York at Albany, Empire State Plaza, P.O. Box 509, Albany, New York 12201-0509
Received March 2, 2009. Revised manuscript received April 29, 2009. Accepted May 11, 2009.
The recent development of a sensitive and accurate analytical method for the analysis of 20 perfluorinated compounds (PFCs), including several short-chain PFCs, has enabled their quantification in tap water collected in China, Japan, India, the United States, and Canada between 2006 and 2008. Of the PFCs measured, PFOS, PFHxS, PFBS, PFPrS, PFEtS, PFOSA, N-EtFOSAA, PFDoDA, PFUnDA, PFDA, PFNA, PFHpA, PFHxA, PFPeA, PFBA, and PFPrA were found at detectable concentrations in the tap water samples. The water samples from Shanghai (China) contained the greatest concentrations of total PFCs (arithmetic mean ) 130 ng/L), whereas those from Toyama (Japan) contained only 0.62 ng/L. In addition to PFOS and PFOA, short-chain PFCs such as PFHxS, PFBS, PFHxA, and PFBA were found to be prevalent in drinking water. According to the health-based values (HBVs) and advisory guidelines derived for PFOS, PFOA, PFBA, PFHxS, PFBS, PFHxA, and PFPeA by the U.S.EPA and the Minnesota Department of Health, tap water may not pose an immediate health risk to consumers.
Introduction Perfluorinated compounds (PFCs) are emerging environmental contaminants of public health concern. PFCs have been manufactured since the 1960s and used in a wide range of consumer and industrial applications. The strong carbonfluorine (C-F) bonds of PFCs impart stability, and thus most * Address correspondence to either author. Nobuyoshi Yamashita tel: +81-29-861-8335; fax: +81-29-861-8335; e-mail: nob.yamashita@ aist.go.jp. Paul K. S. Lam tel: +852-2788-7681; fax: +852-2788-7406; e-mail:
[email protected]. † City University of Hong Kong. ‡ AIST. § National Research Center for Geoanalysis. ⊥ State University of New York. 4824
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of them are resistant to thermal, chemical, and biological degradation. PFCs also possess oil-, stain-, and waterrepellant properties, and therefore are widely applied in textiles, paper products, and carpets. PFCs are also used as surfactants and lubricants and as performance chemicals in fire-fighting foams (i.e., aqueous film-forming foam [AFFF]), shampoos, and pesticides (1). The direct and indirect emissions of these chemicals during their manufacture, use, and disposal, however, have led to their widespread distribution in the environment. PFCs have been detected in air (2), water (3-5), sediment (6, 7), wildlife (8), and human breast milk and blood (9-12) throughout the world. Toxicological studies have demonstrated that two perfluorinated acids, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), in particular, may induce adverse effects in test organisms (13, 14). The presence of contaminants in drinking water can be a source of human exposure to them. Since 1958, the World Health Organization (WHO) has recommended guideline values for chemicals in drinking water. Such values are available for more than 80 chemicals that can occur naturally in drinking water (e.g., arsenic, fluoride, and manganese) or are derived from agricultural and industrial activities (e.g., organochlorine pesticides) (15). In recent years, PFCs have been detected in tap water from Germany, Italy, Spain, Poland, Japan, Malaysia, Thailand, and Vietnam (16-24). However, they have not yet been recommended as candidate chemicals for regulatory monitoring. The sources and exposure pathways of PFCs to the general population have not been well-established, although recent studies suggest that the consumption of PFC-contaminated food can be a major source for PFOS (25-28). Other studies suggest that drinking water can be a potential source, especially for PFOA (21, 24). Tap water can be a major direct source of PFC exposure through ingestion. To date, studies related to tap water have mainly focused on PFOS and PFOA. Several other PFCs are also present in water samples and for accurate exposure and risk assessments, a comprehensive analysis of PFCs in waters is needed. In this study, a newly established method for detecting both short-chain and longchain PFCs was applied to examine contamination in tap water from China and several other countries, including Japan, India, the U.S., and Canada. Since the sample size was small for some countries (i.e., Japan, India, the U.S., and Canada), the results from these countries should be considered as baseline data used for the comparison with tap water samples from China. The risks associated with drinking PFC-contaminated tap water and human exposure to PFCs via drinking water were assessed.
Materials and Methods Reagents and Chemicals. The target analytes included perfluoroalkylsulfonates (C2, 3, 4, 6, 8, and 10), perfluorocarboxylates (C4-C18), perfluorooctanesulfonamide (PFOSA), and N-ethyl perfluorooctane sulfonamidoacetate (N-EtFOSAA). Details of the chemicals and reagents used in the study are given in the Supporting Information (SI). Unfiltered water samples were extracted using solid-phase extraction (SPE) with Oasis WAX cartridges, as described elsewhere (29, 30). Further details of the analysis are also given in the SI. Sample Collection. Tap water samples were collected from 19 cities in 5 countries between 2006 and 2008: China (Xiamen: n ) 5, Taipei: n ) 3, Hong Kong: n ) 5, Macau: n ) 2, Shenzhen: n ) 5, Nanjing: n ) 5, Wuhan: n ) 5, Shanghai: n ) 5, Shenyang: n ) 3, and Beijing: n ) 5), Japan (Osaka: 10.1021/es900637a CCC: $40.75
2009 American Chemical Society
Published on Web 05/29/2009
FIGURE 1. Sampling locations of tap water from China, Japan, India, the U.S., and Canada (details of sample information are given in Supporting Information Tables S1 and S2). n ) 3, Tokyo: n ) 1, and Toyama: n ) 1), India (Patna: n ) 6, Goa: n ) 1, Chennai: n ) 1, and Coimbatore: n ) 1), the U.S. (Albany: n ) 5), and Canada (Niagara-on-the-Lake: n ) 5) (see Figure 1). Most of these cities are metropolitan areas with rapid commercial and industrial development except for a few locations in India. Details regarding the sampling locations are given in Tables S1 and S2 in the SI. The samples were collected directly from the tap in 1-L polypropylene (PP) containers with narrow mouths and screw tops and kept in a refrigerator at 4 °C until analysis. PFCs in tap water were extracted within two months from the time of collection. Instrumental Analysis. Separation of the target analytes was performed using an Agilent HP1100 liquid chromatograph (Agilent, Palo Alto, CA) interfaced with a Micromass Quattro Ultima Pt mass spectrometer (Waters Corp., Milford, MA) that was operated in the electrospray negative ionization mode. A 10-µL aliquot of the extract was injected onto an ion exchange column, the RSpak JJ-50 2D (2.0 mm i.d. × 150 mm length, 5 µm; Shodex, Showa Denko K.K., Kawasaki, Japan), with 50 mM ammonium acetate and methanol as the mobile phase for the quantification of the C2-C5 PFCs. The C6-C12 PFC concentrations were further confirmed by injecting the extracts onto a Keystone Betasil C18 column (2.1 mm i.d. × 50 mm length, 5 µm, 100 Å pore size, end-capped), with 2 mM ammonium acetate and methanol as the mobile phase, and the coefficient of variation was less than 10%. The desolvation gas flow and temperature were kept at 610 L/h and 450 °C, respectively. The collision energies, cone voltages, and MS/MS parameters for the instrument were optimized for the individual analytes and were similar to those reported elsewhere (29, 30). Quality Control and Quality Assurance. To enable the ultra trace-level analysis of the PFCs in tap water, the analytical procedure was subjected to strict quality control and quality assurance by following the ISO method entitled “Water Quality, Determination of Perfluorooctanesulfonate (PFOS) and Perfluorooctanoate (PFOA) - Method for Unfiltered Samples Using Solid Phase Extraction and Liquid Chromatography/Mass Spectrometry”; ISO25101 (ISO/ TC147/SC2/WG56), published in 2009 (31). This method has been validated for drinking water, groundwater, and surface water/seawater by an international round-robin test (involving 23 laboratories in 9 countries). To minimize background contamination throughout the procedure, all known sources of contamination, including accessible poly tetrafluoroethylene (PTFE) and other fluoropolymer materials from the instruments and apparatus, were removed (32). Field blanks and field blank spikes were
used as quality control samples. Milli-Q water was brought to the field for the evaluation of field blank and contamination or loss during transport (field blank spikes). For field blank, the cap of the bottle containing Milli-Q water was opened during the sample collection, and then the cap was closed after sample collection. For field blank spikes, two bottles of Milli-Q water were opened, and spiked with the target compounds at low and high concentrations (2 and 100 ng/ L). All the field blanks, field blank spikes, and samples were transported and stored in the same way. No detectable PFCs ( Nanjing > Shenzhen > Macau > Hong Kong > Taipei > Xiamen > Shenyang > Beijing (see Figure S1). The greatest and least total PFC concentrations were measured in tap water from Shanghai (mean ) 130 ng/L, hereafter mean refers to arithmetic mean) and Beijing (mean ) 0.71 ng/L), respectively. In the Beijing, Shenyang, Xiamen, Nanjing, and Shanghai samples, the concentrations of total PFCAs were 2- to 8-fold higher than those of PFASs. In contrast, the water samples from Taipei, Hong Kong, Macau, Shenzhen, and Wuhan contained total PFAS levels that were greater than or comparable to those of PFCAs. The highest concentration of total PFCs was found in Shanghai and this was in agreement with a previous report showing river water collected from Shanghai (4). This may 4826
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be a consequence of the existence of PFC point source(s), influencing the quality of waters, including tap water, from Shanghai. Beijing is also an industrial city, however, total PFC levels were an order of magnitude lower than those from Shanghai. As advanced drinking water purification methods (such as activated carbon (35)) were employed for drinking water purifications (36, 37), PFCs may be effectively removed in tap water from Beijing. The predominant type of PFAS present in Chinese tap water was PFOS (mean: 3.9 ng/L), followed by PFBS (mean: 2.8 ng/L). PFOS was found at the greatest concentrations in tap water from Shenzhen (11 ng/L), Shanghai (7.6 ng/L), Hong Kong (7.0 ng/L), Macau (6.2 ng/L), Taipei (5.4 ng/L), and Shenyang (0.39 ng/L), whereas PFBS was the predominant PFAS in Wuhan (18 ng/L) and Nanjing (3.5 ng/L). The most predominant PFAS in the tap water from Xiamen and Beijing were PFEtS (0.90 ng/L) and PFHxS (0.085 ng/L), respectively. PFOA (mean 10 ng/L) was the most prevalent PFCA in Chinese tap water overall and was predominant in samples from Shanghai (78 ng/L), Nanjing (5.9 ng/L), Taipei (3.7 ng/L), Shenyang (2.6 ng/L), and Beijing (0.44 ng/L). PFBA and PFHxA, however, existed at the greatest concentrations in tap water from Wuhan (10 ng/L) and Macau (1.7 ng/L), respectively. Although the overall mean concentration of PFPeA in Chinese tap water was relatively low (0.72 ng/L), it was the most prevalent PFCA in samples from Hong Kong (1.8 ng/L) and Xiamen (0.88 ng/L). The composition profiles of PFCs found in Chinese tap water are shown in Figure 3. In samples from Shenzhen, Macau, Taipei, and Hong Kong, PFOS accounted for at least 50% of the total PFCs, whereas in samples from Nanjing, Shanghai, Beijing, and Shenyang, PFOA accounted for >40% of the PFCs. In Wuhan tap water, PFBS accounted for 50% of the total PFCs. The differences in the PFC composition profiles in tap water from different Chinese cities suggest that there may be different sources of PFC contamination in Chinese tap water. The influence of those sources may be localized, resulting in unique patterns of PFC composition in tap water from various locations. When the composition profiles of the PFCs in tap water were compared with those in Chinese river water (4), similar patterns were observed. In samples collected from the Yangtze River near Nanjing and Shanghai, PFOA accounted for 50-80% of total PFCs (which is similar to the PFC composition profiles of the tap water from Nanjing and Shanghai), whereas in water taken from Dongjiang, >50% of the PFCs was PFOS (which is similar to the PFC composition profiles of the tap water from Hong Kong) (Figure 3). These similarities suggest that PFC contamination in tap water may be a consequence of contaminated source water and that water treatment does not remove PFCs effectively, as has been reported previously (24). In Hong Kong, the majority of tap water originates from the Dongjiang River. It is primarily treated via sand filtration and flocculation, which does not remove PFCs (20, 24) effectively. In addition to source water contamination, other potential sources of contamination include distribution and storage systems that use pipelines or water tanks made of materials that contain fluoropolymers. Further studies are needed to identify the potential sources of PFC contamination in Chinese tap water. Concentrations of PFCs in Tap Water from Japan, India, the U.S., and Canada. All of the tap water samples from Japan (Osaka, Toyama, and Tokyo), India (Goa, Coimbatore, Chennai, and Patna), the U.S. (Albany), and Canada (Niagara) contained PFCs (Figure 2). Sixteen PFCs, including PFOS, PFHxS, PFBS, PFPrS, PFEtS, PFPrA, PFOSA, N-EtFOSAA, PFDoDA, PFUnDA, PFDA, PFNA, PFOA, PFHpA, PFHxA, PFPeA, and PFBA were detected in Japanese water samples. The tap water from the U.S. and Canada also contained PFCs similar to those found in China, with the exception
FIGURE 3. Composition profiles of PFCs in (a) tap water samples from China, Japan, India, the U.S., and Canada and (b) Chinese river water from Dongjiang and Yangtze River (4) [Sample size g 3 discussed for tap water samples; PFPrS, PFEtS, PFPeA, and PFBA were not analyzed in Chinese river water)].
FIGURE 4. Global comparisons of PFOS and PFOA levels (ng/L) in tap/drinking water samples (*: This study; N.A.: not analyzed; Reference: a (17); b (23); c (20); d (18); e (21); f (16)). of PFBS, PFOSA, N-EtFOSAA, and PFDoDA, which were absent in samples collected in the U.S. and Canada. Only seven PFCs, PFOS, PFHxS, PFBS, PFOA, PFHxA, PFPeA, and PFBA, were detected in Indian tap water. Similarly to
Chinese tap water, PFDS, PFOcDA, PFHxDA, and PFTeDA were not detected. The concentrations of total PFCs, PFASs, and PFCAs in the tap water from Japan, India, the U.S., and Canada are VOL. 43, NO. 13, 2009 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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shown in Figure S2. PFC concentrations were all lower than those from Shanghai, which was found to have the highest concentrations among the Chinese cities investigated. Beijing’s tap water contained the lowest concentrations of PFCs. The levels of total PFCs in Toyama (Japan) were the lowest (0.62 ng/L). Samples collected in Patna, India (located in the Ganges River basin) showed very low levels of PFCs, as did water samples taken from the Ganges River (38). Similar to Chinese tap water, PFOS and PFOA were the predominant PFCs present in the tap water samples from the U.S. and Canada, accounting for 40-50% of total PFCs. In Osaka, Japan, PFOA was the most prevalent PFC, with a contribution of >40% of the total PFCs, followed by PFNA, which accounted for 20% of the total PFCs. In contrast, tap water from Patna, India, exhibited a different PFC profile, in which PFOA, PFPeA, and PFBA were the only detectable PFCs, with even contributions. Neither PFOS nor PFOA were detected (
