Perfluorinated compounds in surface waters from Northern China ...

Environment International 42 (2012) 37–46

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Environment International j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / e n v i n t

Perfluorinated compounds in surface waters from Northern China: Comparison to level of industrialization Tieyu Wang a, Jong Seong Khim b, Chunli Chen a, Jonathan E. Naile c, Yonglong Lu a,⁎, Kurunthachalam Kannan d, Jinsoon Park b, Wei Luo a, Wentao Jiao a, Wenyou Hu a, John P. Giesy c,e,f a

State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China Division of Environmental Science and Ecological Engineering, Korea University, Seoul 136-713, Republic of Korea Toxicology Centre and Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada d Wadsworth Center, New York State Department of Health and Department of Environmental Health Sciences, School of Public Health, State University of New York, Empire State Plaza, Albany, NY 12201-0509, USA e Department of Zoology and Center for Integrative Toxicology, Michigan State University, East Lansing 48824, MI, USA f Zoology Department, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia b c

a r t i c l e

i n f o

Available online 4 May 2011 Keywords: PFCs Surface water Occurrence Sources Mass flow Risk assessment

a b s t r a c t Inclusion of Perfluorooctane Sulfonate (PFOS) in the Stockholm Convention because of its exemptions, has resulted in increased annual production of PFOS-containing chemicals in China to accommodate domestic and overseas demands. Accordingly, concern about environmental contamination with perfluorinated compounds (PFCs), such as PFOS, has arisen. However, little information is available on the status and trends in the distribution, sources or risk of PFCs in aquatic environments of China. In the present study, forty two surface water samples collected from five regions with different levels of industrialization were monitored for concentrations of PFCs by use of solid phase extraction and LC/MS/MS. Mean concentrations (maximum concentration) of PFOA and PFOS, which were the dominant PFCs, were 1.2 (2.3) and 0.16 (0.52) ng/l for Guanting, 1.2 (1.8) and 0.32 (1.1) ng/l for Hohhot, 2.7 (15) and 0.93 (5.7) ng/l for Shanxi, 6.8 (12) and 2.6 (11) ng/l for Tianjin, 27 (82) and 4.7 (31) ng/l for Liaoning, respectively. The greatest concentrations of PFCs (121 ng/l), PFOA (82 ng/l) and PFOS (31 ng/l) were observed in Liaoning, which might originate from tributaries of the Liaohe River, the most polluted watershed in Northeast China. While, concentrations of PFCs in the Guanting and Hohhot regions were 3 to 20 fold less than those from Tianjin and Liaoning. This result is consistent with little contribution of PFCs being released from agricultural and non-industrial activities. The magnitudes of mass flow for PFOA and PFOS in decreasing order were: Guantingb Hohhot b Tianjinb Liaoning b Shanxi and Guanting b Hohhot b Shanxi b Tianjinb Liaoning. The larger mass flows of PFOS were accompanied by relatively larger magnitudes of PFOA. Concentrations of both PFOA and PFOS in waters from all regions were less than suggested allowable concentrations. However, the relatively greater concentrations of PFCs in Tianjin and Liaoning suggest that further studies characterizing their sources and potential risk to both humans and wildlife are needed. © 2011 Elsevier Ltd. All rights reserved.

1. Introduction Perfluorinated compounds (PFCs) have been manufactured since the 1950s, and their unique properties, such as surface activity, thermal and acid resistance, and water and oil repellency have made them useful in a number of applications and products (Giesy et al., 2010). PFCs have been used as surfactants and surface protectors in carpets, leather, paper, food containers, fabric, and upholstery and as performance chemicals in products such as fire-fighting foams, floor polishes, and shampoos (Giesy and Kannan, 2001; Giesy and Kannan, 2002). The high energy carbon–fluorine bond renders PFCs resistant

⁎ Corresponding author. Tel.: + 86 10 62849466; fax: + 86 10 62918177. E-mail address: [email protected] (Y. Lu). 0160-4120/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.envint.2011.03.023

to hydrolysis, photolysis, microbial degradation, and metabolism by vertebrates (Giesy and Kannan, 2001). Concern about PFCs is growing because they are globally distributed, environmentally persistent, bioaccumulative, and potentially harmful. Giesy and Kannan were the first to report the global distribution of these surfactants when they quantified perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA) and perfluorooctane sulfonamide (FOSA) in extracts of blood plasma and liver samples from marine mammals, birds, fish, as well as human blood (Giesy and Kannan, 2001, 2002). Subsequent studies found PFCs in air (Barber et al., 2007; Chaemfa et al., 2010; Dreyer, 2009); water (Ahrens et al., 2009; Boulanger et al., 2004; Hansen et al., 2002; Saito et al., 2003; So et al., 2004; Yamashita et al., 2004; Yamashita et al., 2005); sediment (Becker et al., 2008; Higgins et al., 2005; Kumar et al., 2009; Naile et al., 2010), and wildlife (Delinsky et al., 2010; Giesy and Kannan, 2001, 2002; Giesy et al.,

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T. Wang et al. / Environment International 42 (2012) 37–46

2006; Houde et al., 2006; Nakata et al., 2006; Shi et al., 2010; Taniyasu et al., 2003). Among PFCs, PFOS and PFOA have received a great deal of attention in recent years. PFOS and PFOA are the terminal degradation products of several precursors, and these two are the major PFCs that have been frequently detected in environmental samples, and often occur at the greatest concentrations. PFOS was recently listed as a “persistent organic pollutant”, under the Stockholm Convention, but many exemptions were made, which allow for continued production and use of some PFCs, especially in China (Wang et al., 2009). Relatively large amounts of PFCs are manufactured and used in China, especially by the textile, leather and paper industries (Chen et al., 2009). China begun large-scale production of PFOS in 2003 with total production of less than 50 t before 2004 (Ministry of Environmental Protection of China, 2008). Since 2005 annual production of PFOS-containing chemicals has grown rapidly due to the sharp increase in domestic demand as well as overseas demands resulting from the restrictions on production of PFOS in other countries since (Bao et al., 2009). Given their water solubility and negligible vapor pressure when dissolved in water, most PFCs can accumulate in aquatic systems and are readily transported by hydrological processes (Taniyasu et al., 2003; Yamashita et al., 2005). Water and sediments are considered final sinks of PFCs and aquatic systems are an important medium for their transport (Hansen et al., 2002). The Yellow River system, Haihe River system, and Liaohe River system are the most important water sources in Northern China. The Haihe River system is the largest catchment in Northern China with its tributaries spanning from Beijing to Tianjin, two large municipalities of China. The Yellow River is the second longest river in China following the Yangtze River, with a total length of 5464 km and meandering across 9 provinces (including Shanxi and Inner Mongolia). The Liaohe River system, which is located in Northeastern China, especially in Liaoning province, encompasses a number of densely industrialized zones, and is recognized as one of the most contaminated rivers in China (Zhang et al., 2006). These three river systems eventually empty into the Bohai Sea. The rapid economic development in this region has brought, and continues to bring about increasing amounts of municipal, industrial and agricultural wastes into the Bohai Sea. The environmental quality in the estuarine and nearby coastal areas has deteriorated by intense industrial and urban activities, and the Bohai Sea is currently one of the most polluted seas in China (Hu et al., 2010; Luo et al., 2010; Naile et al., 2010; Wang et al., 2005b). Some studies have been conducted on the occurrence and distribution of PFCs in Chinese environments since 2004 (Bao et al., 2009; Bao et al., 2010; Chen et al., 2009; Chen et al., 2011; Ju et al., 2008; Liu et al., 2009; Mak et al., 2009; Pan et al., 2010; So et al., 2007; So et al., 2004). However, previous surveys are limited in their scopes and the matrices considered, and relatively few studied sources, distribution, transportation, and potential adverse effects in aquatic environments. The present study was conducted as a systematic investigation to trace sources and fates of toxic substances in various environmental media from adjacent riverine and estuarine areas including the Bohai Sea of China and the West Sea of Korea. The objectives of the present study were to determine concentrations, distribution, and transportation of PFCs in aquatic systems in Northern China to identify sources and potential risks, and thus provide information for future management and remediation efforts on watersheds in Northern China.

PFOS, perfluorodecane sulfonate (PFDS), perfluorobutyric acid (PFBA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), PFOA, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA). HPLC grade methanol and ammonium acetate were purchased from J.T. Baker (Phillipsburg, NJ, USA). Analytical grade sodium thiosulfate was purchased from EMD Chemicals (Gibbstown, NJ, USA). Nano-pure water was obtained from a Milli-Q gradient A-10 (Millipore, Bedford, MA, USA). 2.2. Water sample collection Five sub-regions located in Guanting Reservoir, the largest source of water for Beijing, Hohhot, Shanxi, Tianjin and Liaoning along the Yellow River, Haihe River, and Liaohe River in Northern China, were included in the study area (Fig. 1). Levels of industrialization were determined by use of a comprehensive index that included GDP per capita, non-agricultural product, non-agricultural employment, and the degree of urbanization, informationization and dependence on foreign trade (Cui, 2003). Magnitudes of the index of industrialization were as follows: Guanting b Hohhot b Shanxi b Tianjin b Liaoning. Forty two surface water samples were collected from above mentioned regions including 7 from Guanting Reservoir (G), 8 from Hohhot in Inner Mongolia (H), 9 from Shanxi province (S), 8 from Tianjin Bohai Bay (T), and 10 from Liaoning province (L) (Fig. 1). Global positioning system (GPS) was used to locate sampling sites. Information on sampling sites was summarized in Table 1. One liter of surface water was collected from each sampling station by dipping a clean, methanol-rinsed 1 l polypropylene (PP) bottle just under the surface of water and the container was rinsed 5 times by water from the specific location before sample collection. Residual chlorine in each water sample was reduced by adding 200 μl of 200 mg/ml of sodium thiosulfate solution using a disposable PP syringe. Sample duplicates and field blanks were collected daily and kept at least 20% of the samples in duplicate, thus were analyzed along with laboratory and procedural blanks. All samples were stored on ice for transport to the laboratory and frozen at − 20 °C until analyses. 2.3. Extraction and cleanup

2. Materials and methods

Water samples were extracted using Oasis HLB solid phase extraction cartridges (0.2 g, 6 cm3) (Waters Corp., Milford, MA) as previously reported (Naile et al., 2010; So et al., 2004). Cartridges were preconditioned by elution with 10 ml of 100% methanol followed by 10 ml of nano-pure water at a rate of 2 drops a second. Five hundred milliliters of water was spiked with 500 μl of 5 ng/ml internal standard (isotopically labeled PFOS and PFOA, PFOS [18O2] and PFOA [1,2,3,413C]) and then loaded onto the cartridge, at a rate of 1 drop per second. Cartridges were then washed with 5 ml of 40% methanol in water and allowed to run dry. Eluents were discarded. Target compounds were eluted with 10 ml of methanol at a rate of 1 drop per second and collected in a 15 ml PP tube. The eluate was then reduced to 1 ml under a gentle stream of nitrogen, and filtered using a disposable PP syringe, which had been fitted with a disposable nylon membrane Millex filter unit (pore diameter 0.2 μm, Whatman, Maidstone, United Kingdom). Samples were stored and analyzed in PP auto-sampler vials fitted with PP septa (Canadian Life Science, Peterborough, ON, Canada).

2.1. Standards and reagents

2.4. Instrumental analysis

PFOA [1,2,3,413C] (N98%, Wellington Laboratories, Guelph, Ontario, Canada) and PFOS [18O2] (RTI International, N.C., USA) were used as internal standards. The external standard used for all matrix spikes was a mixture of 12 PFCs (N98%, Wellington Laboratories) including perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS),

An HP 1200 high performance liquid chromatography system (HPLC) by Agilent Technologies was used for separation of all target analytes. The HPLC was fitted with a Thermo Scientific Betasil C18 (100× 2.1 mm, 5 μm particle size) analytical column, and a guard column was used for separation of background from analytes in


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Fig. 1. Map showing sampling locations in Northern China including Guanting Reservoir (G), Hohhot (H), Shanxi (S), Tianjin (T) and Liaoning (L).

samples. An aliquant of 2 mM ammonium acetate was used as an ionization aid. Water and methanol were used as mobile phases. Gradient conditions were: a 300 ml/min flow rate and 10 μl of the sample was injected, starting with 60% A (2 mM ammonium acetate) and 40% B (100% methanol). Initial conditions were held for 2 min and then ramped to 20% A at 18 min, held until 20 min, decreased to 0% A at 21 min, increased to 100% A at 22 min, held until 22.5 min, returned to initial conditions at 23 min, and finally held constant until 26 min. The temperature of the column oven was kept constant at 35 °C. Mass spectra were collected using an Applied Bioscience SCIEX 3000 (Foster City, CA) tandem mass spectrometer, fitted with an electrospray ionization source, operated in negative ionization mode. Chromatograms were recorded in multiple reaction monitoring mode (MRM) with a dwell time of 40 ms. The following instrument parameters were used: desolvation temperature (450 °C), desolvation (curtain) gas 6.0 arbitrary units (AU); nebulizer gas flow 5 AU; ion spray voltage −3500 V; and collision gas 12 AU. Optimal settings for collision energies and declustering potential were determined for each analyte's MRM transitions. Quantification using these transitions was performed using Analyst 1.4.1 software (Applied Bioscience, Foster City, CA). 2.5. Quality assurance and control In order to ensure the accuracy of sampling, extraction, and analytical procedures, field blanks were collected with each set of water samples analyzed. Procedural blanks and recoveries were determined for each set of extractions. Quantification was performed using the internal standard method based on 18O2-PFOS and 13C4-PFOA,

as the surrogate. To reduce instrument background contamination arising from HPLC or solvents, a ZORBEX (Thermo Scientific, 50× 2.1 mm, 5 μm particle size) column was inserted directly before the injection-valve, as adapted from Benskin et al. (2007). All field and laboratory blanks were less than the limit of quantification (LOQ), which was defined as 5 times the background signal of solvent blanks. The use of Teflon coated lab-ware was avoided during all steps of sample preparation and analysis to minimize contamination of the samples. The ions monitored, method detection limit (MDL), and matrix spike recoveries for all the target chemicals are summarized (Table 2). 2.6. Statistical analysis All statistical analyses were preformed with SPSS Statistics V17.0. Concentrations below LOQ were assigned as LOQ/sqrt(2) during summary statistics. Spatial distributions of PFCs were analyzed using ArcGIS V9.0 software (ESRI). 3. Results and discussion 3.1. Occurrence of PFCs in surface water Concentrations and relative proportions of PFCs in surface waters from locations with five different indices of industrialization in Northern China are summarized (Table 3, Fig. 2). Among the seven detectable PFCs, PFOA and PFOS occurred at the greatest concentrations in all sub-regions. Respective ranges of concentrations of PFOA and PFOS were 0.55 to 2.3 ng/l and bLOQ to 0.52 ng/l in Guanting, 0.80 to 1.8 ng/l and bLOQ to 1.1 ng/l in Hohhot, 0.43 to 15 ng/l and b LOQ to 5.7 ng/l in Shanxi, 3.0 to 12 ng/l and 0.09 to 11 ng/l in Tianjin, 2.6 to 82 ng/l and b LOQ to 31 ng/l in Liaoning. Mean concentrations of PFOA and PFOS in rivers of Northern China were as follows: Guanting (1.2 ng/l)= Hohhot

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Table 1 Sampling information including location, flow rate and detailed description. Flow ratea (m3/d)

Code

Province or city

Riverine

G01 G02 G03 G04 G05 G06 G07 H01 H02 H03 H04 H05 H06 H07 H08 S01 S02 S03 S04 S05 S06 S07 S08 S09 T01 T02 T03 T04 T05 T06 T07 T08 L01 L02 L03 L04 L05 L06 L07 L08 L09 L10

Yanqing Huailai

Guishui River Guanting Lake

773 000 383 600

Yanghe River Sanggan River

2 898 600 1 932 400

Xiaohei River Dahei River

191 800 1 175 100

a

Hohhot

Shilawusu River Yellow River

164 400 69 863 000

Lishi

Yellow River

92 301 400

Taiyuan

Fen River

Linfen Yuncheng

Yellow River

92 301 400

Tianjin

Chaobai River

3 616 400

Yongding River

5 062 900

Haihe River

7 232 800

Duliujian River Ziya River Liugu River

2 411 000 3 888 000 792 000

Jinzhou

Xiaoling River Daling River

2 155 200 3 780 800

Panjin

Liaohe River

4 843 800

Yingkou

Taizi River

2 421 900

Huludao

4 027 400

Characteristics

Sampling date

Natural park and touristic Orchard and town Agriculture and touristic Water treatment pool River mouth, agriculture River mouth, agriculture Dam and bridge Midstream, agriculture Upstream, near a industrial Midstream, agriculture River mouth, urban and industrial Midstream, agriculture Downstream, industrial River mouth, sewage drainage Downstream, agriculture Upstream, agriculture Midstream, agriculture Midstream, Touristic River mouth, agriculture Upstream, urban and industrial Midstream, agriculture and urban Downstream, sewage drainage Downstream, agriculture Downstream, urban and industrial Downstream, industrial River mouth, coastal, industrial Midstream, industrial Downstream, industrial Downstream, sewage treatment plant River mouth, coastal, harbor River mouth, sewage drainage Downstream, agriculture Downstream, industrial River mouth, harbor Downstream, pre-industrial Midstream, oil plant Midstream, chemical industry River mouth, sewage drainage Midstream, industrial River mouth and coastal, harbor Downstream, industrial River mouth, coastal, industrial

05/2007 05/2007 05/2007 05/2007 05/2007 05/2007 05/2007 08/2006 08/2006 08/2006 08/2006 08/2006 08/2006 08/2006 08/2006 04/2008 04/2008 04/2008 04/2008 04/2008 04/2008 04/2008 04/2008 04/2008 05/2007 05/2007 05/2007 05/2007 05/2007 05/2007 05/2007 05/2007 05/2008 05/2008 05/2008 05/2008 05/2008 05/2008 05/2008 05/2008 05/2008 05/2008

Data obtained from website of the Ministry of Water Resources of China.

(1.2 ng/l) b Shanxi (2.7 ng/l) b Tianjin (6.8 ng/l) b Liaoning (27 ng/l), and Guanting (0.16 ng/l)b Hohhot (0.32 ng/l)b Shanxi (0.93 ng/l)b Tianjin (2.6 ng/l)b Liaoning (4.7 ng/ l). Concentrations of PFOS and PFOA in surface waters were directly proportional to the magnitude of the index of industrialization. Although PFOS and PFOA were the dominant PFCs found in waters during the present study, PFHpA, PFDA, PFDoA, and PFHxS were also detected in approximately 60% of samples at concentrations greater than the respective LOQ, but concentrations of these PFCs were less than those of PFOA and most concentrations of PFOS, except for the concentration of PFHpA in Liaoning (5.9 ng/l). Concentrations of PFHpA, PFDA,

PFDoA and PFHxS were comparable in Guanting and Hohhot, but less than those in Shanxi, Tianjin and Liaoning. The greatest concentrations of these PFCs were observed in Liaoning with maximum concentrations of PFHpA (35 ng/l), PFDA (5.7 ng/l), PFDoA (0.24 ng/l) and PFHxS (2.3 ng/l). This indicates that other PFCs, not just PFOS and PFOA, should be considered in future monitoring and risk assessment. However, it should be noted that the reported concentrations of waterborne PFCs were based on a single survey, thus temporal variations could not be addressed at this time. Further studies should investigate the monthly or seasonal variations in PFC concentrations.

Table 2 Limit of quantification (LOQ), method detection limit (MDL) and matrix spike recovery (MSR) of target compounds. Analyte

Acronym

LOQ (ng/l)

MDLa (ng/l)

MSR (%)

Detected ratiob (%)

Perfluorobutane sulfonate Perfluorohexane sulfonate Perfluorooctane sulfonate Perfluorodecane sulfonate Perfluorobutanoic acid Perfluorohexanoic acid Perfluoroheptanoic acid Perfluorooctanoic acid Perfluorononanoic acid Perfluorodecanoic acid Perfluoroundecanoic acid Perfluorododecanoic acid

PFBS PFHxS PFOS PFDS PFBA PFHxA PFHpA PFOA PFNA PFDA PFUnA PFDoA

0.5 0.1 0.1 0.1 1.0 0.5 0.5 0.5 1.0 0.1 1.0 1.0

1.0 0.2 0.2 0.2 2.0 1.0 1.0 1.0 2.0 0.2 2.0 2.0

94 ± 40 137 ± 15 101 ± 22 101 ± 21 120 ± 19 85 ± 58 103 ± 16 88 ± 25 132 ± 23 93 ± 13 112 ± 22 77 ± 17

0(0) 13(31) 29(69) 0(0) 0(0) 0(0) 26(62) 42(100) 5(12) 26(62) 0(0) 24(24)

a b

The MDL was defined as the amount of chemical which could be detected in a given amount of sample after the entire method was preformed. Number of samples detected and % — occurrence in parenthesis given.


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Table 3 Concentrations (ng/l) of PFCs in waters from Northern China (the values in bracket indicate the standard errors and ranges). Location

Guanting

Hohhot

Shanxi

Tianjin

Liaoning

Sample size

7

8

9

8

10

PFOS PFOA PFHpA PFNA PFDA PFDoA PFHxS ∑ PFCs

0.16 1.2 0.06 0.02 0.10 0.11 0.03 1.7

0.93 (0.64, nd–5.7) 2.7 (1.5, 0.43–15) 0.32 (0.12, nd–0.96) nd 0.07 (0.01, 0.03–0.13) 0.06 (0.02, nd–0.14) 0.78 (0.63, nd–5.8) 4.8 (1.8, 0.55–16)

2.6 (1.2, 0.09–11) 6.8 (1.1, 3.0–12) 0.87 (0.26, 0.37–2.6) 1.1 (0.61, nd–4.9) 1.1 (0.51, 0.06–3.8) 0.10 (0.02 0.05–0.20) 0.01 (0.01, nd–0.06) 13 (2.7, 4.4–25)

4.7 (3.0, nd–31) 27 (10, 2.6–82) 5.9 (3.3, 0.34–35) 0.14 (0.13, nd–1.4) 0.68 (0.56, nd–5.7) 0.03 (0.02, nd–0.24) 0.90 (0.28, nd–2.3) 39 (12, 3.2–121)

(0.08, (0.23, (0.04, (0.01, (0.03, (0.04, (0.03, (0.36,

nd–0.52) 0.55–2.3) nd–0.22) nd–0.06) 0.04–0.23) nd–0.29) nd–0.19) 0.75–3.1)

0.32 1.2 0.04 0.02 0.07 0.21 0.02 1.8

(0.12, (0.12, (0.02, (0.02, (0.02, (0.01, (0.01, (0.15,

nd–1.1) 0.80–1.8) nd–0.11) nd–0.14) 0.03–0.18) 0.16–0.27) nd–0.08) 1.1–2.5)

nd: less than limit of quantification.

Since PFOA and PFOS were the dominant PFCs found in water samples accounting for over 70% of the total concentrations of PFCs in all study areas and detected in most of the samples at concentrations greater than the LOQ (Table 2), the subsequent discussion will be focused on PFOA and PFOS. When compared to values for other regions of China, concentrations of PFOA in waters from Guanting and Hohhot were comparable to or less than those from Wuhan, Nanjing, Yichang, Dongguan and Hong Kong, but less than those from Shanghai and Dalian. Concentrations of PFOA in Shanxi and Tianjin were greater than those from most Chinese cities, but still less than those from Shanghai (260 ng/l). Moreover, the concentration of PFOA in Shanghai was higher than those from Liaoning, which showed the highest concentration of PFOA (82 ng/l) (Table 4, see therein references). Concentrations of PFOS in waters in Guanting and Hohhot were comparable to those from Chongqing, Yichang, Nanjing, and Dalian. Concentrations of PFOS in Shanxi and Tianjin were similar to those from Beijing, Shenyang, Wuhan, Hong Kong and Pearl River Delta. However, even the greatest concentration of PFOS in Liaoning (31 ng/l) was less than those from Dongguan (99 ng/l), which has several electronic industries such as printed circuit boards and electroplating that could be local sources of PFOS. A comparison of the results obtained in the present study with those of previous studies conducted in adjacent areas is presented (Table 4). In general, concentrations determined in this study were greater than those found in offshore waters of Japan and oceanic samples from the Western Pacific Ocean, Central to Eastern Pacific Ocean and North Atlantic Ocean (Yamashita et al., 2005). Concentrations of PFOA in Shanxi and Tianjin were comparable to or less than those detected in coastal waters of Korea (Yamashita et al., 2005), Kyoto River in Japan (Senthilkumar et al., 2007), and Cooum River in India (Yeung et al., 2009), but much less than those from the Yodo River basin (Lein et al., 2008). In the present study, the maximum concentration of PFOA (82 ng/l), which was measured in Liaoning, was comparable to those observed in coastal areas of Korea (Naile et al., 2010) including Gyeonggi Bay (Rostkowski et al., 2006), and the Chao Phraya River in Thailand (Kunacheva et al., 2009), but less than the greatest

concentrations of PFOA (2600 ng/l) measured in the Yodo River Basin (Lein et al., 2008), which is one of the most polluted areas in Japan. Concentrations of PFOS in Shanxi, Tianjin and Liaoning were comparable to or less than those reported from South Korea, Japan, India and Thailand. The maximum concentration of PFOS (31 ng/l) was measured in Liaoning, which was much less than the greatest concentrations of PFOS measured in the Yodo River Basin (123 ng/l), Kyoto (110 ng/l) in Japan, and the Korean coast (450 and 730 ng/l) including Gyeonggi Bay (651 ng/l) in Korea (Table 4, see references therein). 3.2. Spatial distribution of PFCs in surface water Spatial patterns of PFOA and PFOS as well as total PFC concentrations in surface waters from five industrial regions in Northern China were plotted using ArcGis software (ESRI) (Fig. 3). The greatest concentration of PFCs (3.1 ng/l) was found at location G02 in Guanting Reservoir, with the highest values of PFOA (2.3 ng/l) and second highest value of PFOS (0.34 ng/l). That sample was collected from a river adjacent to the Beixinpu region, which has intensive agricultural activities (orchard and facility agriculture) with significant pesticide consumption every year (Wang et al., 2007). Greater concentrations of HCH, DDT and heavy metals were observed in soils throughout the Guanting area as well (Luo et al., 2007; Wang et al., 2005a), which suggests local sources of pollution from agricultural run-off. Meanwhile, this catchment area is the major water source for Beijing and is considered unpolluted with industrial chemicals. Concentrations of PFOA and PFOS in Guanting Reservoir water are generally less than those from Shanxi, Tianjin and Liaoning. The Liaoning region had the greatest total PFC concentrations (121 ng/l) and PFOA at L06 (82 ng/l), as well as greatest PFOS at L09 (31 ng/l), where one of the largest chemical industrial areas of China has been since the 1960s. There still exist many oil refining plants, chemical plants, and smelting plants in this region. In the present study,

Fig. 2. Total concentrations of PFCs and relative compositions in surface waters of Northern China.

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Table 4 Comparison of PFOS and PFOA concentrations (ng/l) in waters with other studies in these adjacent areas.

China

Japan

South Korea

India Thailand Ocean

Location

PFOS

PFOA

Reference

Guanting Hohhot Shanxi Tianjin Liaoning Coastal area of China Beijing Dongguan Chongqing Yichang Wuhan Nanjing Shanghai Pearl River Delta Dalian Coast Hong Kong Tokyo Bay Tokyo Bay Survey of Japan Yodo River basin Kyoto offshore of Japan Coastal of Korea Coastal of Korea Korea coast Gyeonggi Bay Cooum River Chao Phraya River Western Pacific Ocean Central to Eastern Pacific Ocean North Atlantic Ocean

nd–0.52 nd–1.1 nd–5.7 0.10–11 nd–31 0.02–9.68 1.75–4.09 0.90–99 nd–0.35 0.29–0.61 2.3–5.3 0.33–0.38 0.62–14 0.02–12 nd–2.25 0.09–3.1 12.7–25.4 0.78–17 0.89–5.73 0.4–123 7.9–110 0.04–0.07 0.04–2.53 0.04–730 4.11–450 2.24–651 0.04–3.91 0.7–17.9 0.054–0.078 0.001–0.020 0.009–0.036

0.55–2.3 0.80–1.8 0.43–15 3.0–12 2.6–82 0.24–15.3 5.51–7.85 0.85–4.4 nd–35 4.1–4.9 2.8–5.6 2.1–2.4 22–260 0.24–16. 0.17–37.6 0.73–5.5 154–192 2.7–63 0.97–21.5 4.2–2600 5.12–10 0.14–1.06 0.24–11.4 0.24–320 2.95–68.6 0.9–62 0.04–23.1 0.7–64.3 0.136–0.142 0.015–0.062 0.160–0.338

Present study

Yamashita et al., 2005 Zhao et al., 2007 So et al., 2007 So et al., 2007 So et al., 2007 Jin et al.,2006 So et al., 2007 So et al., 2007 So et al., 2004 Ju et al., 2008 So et al., 2004 Yamashita et al., 2004 Sakurai et al., 2010 Saito et al., 2003 Lein et al., 2008 Senthilkumar et al., 2007 Yamashita et al., 2005 Yamashita et al., 2005 So et al., 2004 Naile et al., 2010 Rostkowski et al., 2006 Yeung et al., 2009 Kunacheva et al., 2009 Yamashita et al., 2005 Yamashita et al., 2005 Yamashita et al., 2005

water samples were collected mainly from the Liaohe River system, which is one of the most contaminated water bodies in China. The watershed encompasses a number of densely industrialized zones, which specialize in machinery, electronics, metal refining, and petroleum and chemical industries (Zhang et al., 2006). The Liaohe River system is influenced by discharge of sewage from the surrounding cities, and receives about 2 billion t of industrial and domestic wastewater annually (Zhang et al., 2009). There are significant differences in the types of industries between Shanxi and Tianjin, with traditional heavy industries such as coking plants and smelting plants in Shanxi, and high technology industries such as petrochemicals and electronic plants in Tianjin. The greatest concentrations of PFCs, PFOA and PFOS were found at locations S09 (16 ng/l), S09 (15 ng/l) and S07 (5.7 ng/l) in Shanxi, respectively, which are located downstream of the rivers including the Yellow River and the Fen River. The results indicate an increasing concentration from upstream to downstream of the rivers except for some point sources. The greatest concentrations of PFCs, PFOA and PFOS were observed at same location T05 with 25 ng/l, 12 ng/l and 11 ng/l in Tianjin, respectively. This sample was collected from the Haihe River, near a sewage treatment plant; moreover, the Haihe River receives abundant industrial and domestic wastewater from nearby cities (Shi et al., 2005; Zhang et al., 2009). As for Hohhot, the capital city of Inner Mongolia, concentrations of PFCs, PFOA and PFOS were generally very low, ranging from 1.1 to 2.5 ng/l, 0.80 to 1.8 ng/l, and b LOQ to 1.1, respectively. The greatest concentrations of PFCs (2.5 ng/l) and PFOA (1.8 ng/l) were observed in location H04. Elevated concentrations of PFOA (1.3 ng/l) and PFOS (1.1 ng/l) were found in upstream locations (H02 and H03). These sites, located along the Dahei River, near an emerging industrial zone, were influenced by local sources of PFOS and PFOA from industrial effluents. In general, the rivers in the Hohhot region surveyed in this study flow are mostly in grasslands, forests, agricultural and rural areas. These areas are considered as background areas with less industrialization and urbanization. Concentrations of PFCs, especially PFOA and PFOS in water from the sites surveyed in this region were less than those of Tianjin and Liaoning.

enter the Bohai Sea and higher concentrations of PFOS and PFOA were found at sites T07, L06, L08 and L10 (Fig. 3). Concentrations of PFCs in waters from Guanting and Hohhot were 3- to 20-fold less than those from Tianjin and Liaoning, which is consistent with little contribution of PFCs from agricultural and non-industrial activities. Some indicators including ratios of PFOS to PFOA and PFHpA to PFOA have been applied to identify potential sources of PFCs (Simcik and Dorweiler, 2005; So et al., 2004). The PFOS/PFOA ratios in the present study were generally less than 1.0, but some samples such as H02 (1.34) from Hohhot, S06 (1.77) and S07 (9.66) from Shanxi, and L09 (8.86) from Liaoning, exhibited higher PFOS concentrations than PFOA (Table 5), which is indicative of potential point sources of PFOS. It is noteworthy that above mentioned sites are close to industrial areas; especially S07 which was collected in the vicinity of sewage outfall along the Fen River. Ratios calculated in our study are generally consistent with findings in Lake Michigan and the Tennessee River in the United States, and coastal waters of China and Korea (Hansen et al., 2002; Simcik and Dorweiler, 2005; So et al., 2004). PFHpA was detected in most surface waters (detected ratio: 62%) and in some cases PFHpA was the dominant PFC in water. PFHpA concentrations ranged from b LOQ to 35 ng/l at L06 in Liaoning. Few studies have reported the dominance of this PFC in surface waters. However, Simcik and Dorweiler (2005) described relatively higher concentrations due to atmospheric deposition of PFHpA to surface waters. Therefore, the ratio of PFHpA to PFOA was used as a tracer of atmospheric deposition. This ratio varied among regions in Northern China with a range of 0.02 (S09) to 0.99 (L10), for all water samples the ratio is less than unity indicating that PFOA concentrations exceeded the PFHpA concentrations (Table 5). This result was expected since there are non atmospheric sources of PFOA and also PFOS to these surface waters. The greater concentrations of PFHxS at Shanxi (S07 = 5.8 ng/l), PFNA at Tanjin (T07 = 4.9 ng/l) and PFDA at Liaoning (L09 = 5.7 ng/l) were consistent with some local sources of these PFCs, which generally occurred at much smaller concentrations.

3.3. Industrial sources of PFCs

3.4. Mass flow of PFCs

Greater concentrations of PFCs in waters from Tianjin and Liaoning may have originated from tributaries, of which the Haihe River and Liaohe River are the two major tributaries. These watersheds contain a variety of industries including chemical and biochemical product manufacturing, petrochemicals, printed circuit boards, bleaching, dyeing, pharmaceuticals, electroplating, and fire-fighting foams. The Haihe River receives industrial and domestic discharges mainly from Tianjing and Beijing, which are highly urbanized cities with increasing industrial and commercial activities. The Liaohe River receives industrial and domestic contaminants mainly from Jinzhou, Huludao, Panjin, Yingkou and Shenyang, the important industrial bases of Liaoning province, with highly industrialized and urbanized cities. Discharges from these rivers

Riverine transport is the major mode for the transport and mobilization of contaminants to the sea. Rivers receive the input of treated or untreated sewage effluents and industrial discharges and agricultural run-off. Estimated mass flows of PFOA and PFOS in rivers in Northern China are presented (Table 5). For this estimation, the single point measurements of concentrations were multiplied by average daily discharges of water. The magnitudes of mass flow for PFOA and PFOS in the five industrial regions in decreasing order were: Guanting b Hohhotb Tianjinb Liaoningb Shanxi and Guantingb Hohhotb Shanxib Tianjinb Liaoning. The mass flow of PFOS generally increased from upstream to downstream in Hohhot, Shanxi and Liaoning, whereas the increasing mass flow of PFOS was accompanied by a


Fig. 3. Spatial distribution of PFCs in surface waters of Northern China.

43

44


Table 5 Parameters for sources, mass flow and potential risk of PFOS and PFOA. Code

PFOS

PFOA

ng/l G01 G02 G03 G04 G05 G06 G07 H01 H02 H03 H04 H05 H06 H07 H08 S01 S02 S03 S04 S05 S06 S07 S08 S09 T01 T02 T03 T04 T05 T06 T07 T08 L01 L02 L03 L04 L05 L06 L07 L08 L09 L10

nd 0.34 nd 0.52 0.14 nd 0.15 nd 1.1 0.06 0.30 0.39 0.35 0.25 0.14 0.12 nd nd nd nd 2.3 5.7 0.16 0.15 0.74 3.3 0.10 2.4 11 1.5 1.6 0.29 3.7 nd nd 4.5 nd nd nd 6.7 31 1.4

1.1 2.3 1.2 1.8 0.88 0.68 0.55 1.2 0.82 1.3 1.8 0.99 1.0 1.4 0.80 1.1 0.64 0.43 0.77 3.1 1.3 0.59 1.4 15 7.8 6.6 5.0 5.1 12 4.4 11 3.0 9.1 2.6 2.9 68 72 82 7.8 7.6 3.5 11

Mass flow

Sources indicators PFOS/PFOA

PFHpA/PFOA

PFOS (g/d)

0.15

0.10

0.1

0.29 0.16

0.11

0.2 0.4

0.27

0.3

1.34 0.05 0.17 0.39 0.35 0.18 0.17 0.11

1.2 0.1 0.4 0.5 0.1 17.4 9.6 10.6

1.77 9.66 0.11 0.01 0.10 0.50 0.02 0.47 0.92 0.34 0.15 0.10 0.41

0.07

0.88 8.86 0.13

0.06 0.10 0.07 0.72

0.12 0.74 0.10 0.33 0.02 0.12 0.06 0.17 0.12 0.05 0.12 0.24 0.12 0.05 0.65 0.12 0.02 0.04 0.43 0.35 0.38 0.46 0.99

decrease in conductivity towards the estuarine mouth (H08, S08, T06 and L10) due to dilution by the tributary or seawater such as the Yellow River in Hohhot and Shanxi, Bohai Sea in Tianjin and Liaoning. The larger mass flows of PFOS in H07 (17.4 g/d), S09 (14.0 g/d), and T05 (75.6 g/d) were accompanied by corresponding larger mass flows of PFOA, due to local sources from the discharge of sewage drainage and industrial effluents. The larger mass flows of PFOA at locations H07 (100.8 g/d), S09 (1346.0 g/d), T05 (86.6 g/d), and L04 (257.5 g/d), L05 (273.0 g/d) and L06 (308.9 g/d) can be explained by influences of different types of sources. Locations H07, T05 and L06 are influenced by the discharge of sewage, which had the greatest concentrations of PFOA. Locations S09, L04 and L05 are influenced by industrial effluents (Table 1). A large industrial park is located between locations L04 and L06, near the city of Jinzhou, which consists of a variety of chemical factories such as petroleum, textile-coloring and polymer industries. Each facility has its own wastewater treatment plants, thus, the larger mass flow at location L06 is likely caused by industrial discharges. Multiple sources of PFCs have been identified, indicating that they are common and widespread. 3.5. Hazard assessment of PFCs PFCs have not been regulated in China, however, maximum concentrations to protect the most sensitive aquatic species have been suggested. Multiple approaches are available to derive environmental quality values and the most commonly used are the Great Lakes Initiative guidelines of the USEPA (Sanchez-Avila et al., 2010). The values are calculated using reported acute and subacute toxicity values of PFOS and PFOA to aquatic organisms and birds (Giesy et al., 2010). Recently, Giesy et al. (2010) calculated suggested criteria maximum concentrations (CMC) for the most sensitive aquatic species, such as Daphnia magna for PFOS (21 μg/l) and PFOA (25 mg/l), and criteria continuous concentration (CCC) for PFOS (5.1 μg/l) and PFOA (2.9 mg/l), as well as avian wildlife values (AWV) for PFOS (47 ng/l). An evaluation of the ecological risk to aquatic animals associated with exposure to PFOA and PFOS was performed by comparing concentrations in water with the suggested allowable concentrations.

9.2 22.9 14.6 14.0 2.7 12.1 0.5 12.1 75.6 10.5 3.9 1.1 2.9

17.2

32.6 74.8 3.5

Hazard quotient PFOA (g/d) 0.8 0.9 0.4 0.7 2.5 1.3 1.1 0.2 1.0 1.5 2.1 1.2 0.2 100.8 56.0 102.5 58.8 39.7 71.4 12.4 5.2 2.4 132.3 1346.0 28.2 23.9 25.4 25.8 86.6 31.5 25.6 11.7 7.2 2.0 6.2 257.5 273.0 309.0 37.6 36.6 8.4 25.9

PFOS/AWV

PFOS/CCC

0.007

b0.001

0.011 0.003

b0.001 b0.001

0.003

b0.001

0.023 0.001 0.006 0.008 0.007 0.005 0.003 0.003

b0.001 b0.001 b0.001 b0.001 b0.001 b0.001 b0.001 b0.001

0.049 0.121 0.003 0.003 0.016 0.070 0.002 0.051 0.234 0.032 0.034 0.006 0.079

b0.001 0.001 b0.001 b0.001 b0.001 b0.001 b0.001 b0.001 0.002 b0.001 b0.001 b0.001 b0.001

0.096

b0.001

0.143 0.660 0.030

0.001 0.006 b0.001

PFOA/CCC b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001 b 0.001

Concentrations of PFOA and PFOS measured in surface waters in present study (all ng/l level) were less than the suggested allowable concentrations to protect aquatic life of wildlife that would consume aquatic organisms. The observed concentrations of PFOA and PFOS were several orders of magnitude less than their corresponding CMC values and 150–1000 times less than the CCC values, and avian wildlife guideline values for PFOS (Table 5). While the results indicate negligible risk to wildlife, based on concentrations measured in water, several uncertainties on the toxicities of PFCs at less concentrations exist. More toxicological and environmental exposure data are needed to address the effects of PFCs on environmental systems (Beach et al., 2006). Also, to make comparisons between concentrations in organisms associated with adverse effects, concentration in the blood, liver and or eggs of birds would be necessary since these are the only values available for which to calculate toxicity reference values (TRVs) (Newsted et al., 2006; Newsted et al., 2008; Newsted et al., 2007; Newsted et al., 2005; Yoo et al., 2008).

Acknowledgments This study was supported by the National Natural Science Foundation of China under Grant No. 41071355, the National Basic Research Program of China (“973” Research Program) with Grant No. 2007CB407307, the National S&T Support Program under Grant No. 2008BAC32B07, and Environmental Protection Welfare Program under Grant No. 201009032. Portions of the research were supported by a Discovery Grant from the National Science and Engineering Research Council of Canada (Project No. 326415-07) and a grant from the Western Economic Diversification Canada (Project Nos. 6971 and 6807). Professor Giesy's participation in the project was supported by the Einstein Professorship Program of the


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