Chemosphere 80 (2010) 123–130

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Chemosphere

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Perfluorinated compounds in urban river sediments from Guangzhouand Shanghai of China

Jia Bao a, Wei Liu a, Li Liu b, Yihe Jin a,*, Xiaorong Ran c, Zhixu Zhang c

a School of Environmental and Biological Science and Technology, Dalian University of Technology, Key Laboratory of Industrial Ecology and Environmental Engineering,Ministry of Education, Dalian 116024, Chinab Department of Social Medicine, School of Public Health, China Medical University, No. 92 Beier Road, Heping District, Shenyang 110001, Chinac Life Sciences and Chemical Analysis, Agilent Technologies Co., Ltd., No. 3 Wang Jing North Road, Chao Yang District, Beijing 100102, China

a r t i c l e i n f o

Article history:Received 10 November 2009Received in revised form 23 February 2010Accepted 2 April 2010Available online 28 April 2010

Keywords:Perfluorooctane sulfonate (PFOS)Perfluorooctanoic acid (PFOA)River sedimentUrban area

0045-6535/$ - see front matter � 2010 Elsevier Ltd. Adoi:10.1016/j.chemosphere.2010.04.008

* Corresponding author at: School of EnvironmentTechnology, Dalian University of Technology, No. 2 LiChina. Tel./fax: +86 411 84708084.

E-mail address: jinyihe@dlut.edu.cn (Y. Jin).

a b s t r a c t

Perfluorinated compounds (PFCs) have been determined in various matrices within China includingwater bodies, precipitations, biota and non-occupationally PFCs-exposed populations in recent years,yet little attention has been focused on the distributions of PFCs in urban river sediments from Chinesemajor metropolises such as Guangzhou and Shanghai so far. In this study, sediment samples of 0–2 cmwere collected from 13 sites in the Zhujiang River across Guangzhou and nine sites in the HuangpuRiver across Shanghai. PFCs analysis on these sediments via high performance liquid chromatogra-phy-tandem mass spectrometry (HPLC–MS/MS) system was implemented targeting eight analytesinvolving perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfo-nate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid(PFDA), perfluorododecanoic acid (PFDoA) and perfluorotetradecanoic acid (PFTA). According to theanalytical results, total concentrations of PFCs (

PPFCs) in sediments from the Zhujiang River were

between 0.09 and 3.6 ng/g dry weight (dw), with PFOS being the dominant PFC contaminant in theriver ranged from below LOD to 3.1 ng/g dw; while

PPFCs in sediments from the Huangpu River were

between 0.25 and 1.1 ng/g dw, with PFOA being the main PFC contaminant in the river determined inthe levels of 0.20–0.64 ng/g dw. Additionally, an overall decreasing trend of PFCs contaminations withdepth was observed in both of two 60 cm sediment cores from the Zhujiang River and the HuangpuRiver each.

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1. Introduction

Perfluorinated compounds (PFCs) consisting of perfluorosulfo-nates (PFSAs) and perfluorocarboxylates (PFCAs) have been pro-duced and applied as surfactants and surface protectors incarpets, leather, paper, packaging, fabric, and upholstery, and inor as aqueous film fire-fighting foams (AFFFs), mining and oil wellsurfactants, alkaline cleaners, floor polishes, photographic film,denture cleaners, shampoos, and insecticide, for more than50 years (OECD, 2002). PFCs are featured with their chemical andthermal stabilities as well as both hydrophobicity and oleophobic-ity resulting from the extremely strong C–F bonds in their chemicalstructures (Kissa, 2001). In recent years, other environmental char-acteristics of these compounds regarding their bioaccumulation(Martin et al., 2004b; Houde et al., 2006), various toxicities (Lau

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al and Biological Science andnggong Road, Dalian 116024,

et al., 2004; Shi et al., 2008), and potential for long range transpor-tation (Martin et al., 2004a) have also been investigated by theresearchers globally. According to the screening criteria for persis-tent organic pollutants (POPs) under the Stockholm Convention,perfluorooctane sulfonate (PFOS) and its salts together with its pre-cursor, perfluorooctane sulfonyl fluoride (PFOSF), were conse-quently added to Annex B of the convention in May of 2009,calling for restricted use worldwide (UNEP, 2009).

China began large-scale production of PFOS in 2003. Before theyear of 2004, the total production of PFOS within China was lessthan 50 tons, while the annual production of PFOSF increased shar-ply to over 200 tons in 2006 owing to the increasingly widespreaddomestic applications and progressively overseas demands result-ing from the restrictions on PFOS production in developed coun-tries since 2005. In detail, around 100 tons of PFOSF wereexported to EU, Japan, and Brazil in 2006 (Ministry of Environmen-tal Protection of China, 2008). However, there are no limitations onthe production of PFOS within Chinese regions yet.

Research on the occurrences and distributions of PFCs in Chinaso far have been mainly focused on water bodies (So et al., 2004,

124 J. Bao et al. / Chemosphere 80 (2010) 123–130

2007; Ju et al., 2008), precipitations (Liu et al., 2009), biota (Li et al.,2008a,b), and non-occupationally PFCs-exposed populations(Yeung et al., 2006, 2008; Jin et al., 2007). Recently, our researchdemonstrated the distributions of sediment PFCs in the Daliao Riv-er system of northeast China (Bao et al., 2009).

Sediment has been regarded as an important sink and reservoirof PFCs (Prevendouros et al., 2006). Sediment-associated PFCs wereproved to show good bioavailability to aquatic organisms (Higginset al., 2007) and relatively greater water solubility compared toother POPs (Nakata et al., 2006), they would thus be able to trans-fer into aquatic organisms leading to bioaccumulation and eventrophic biomagnification in aquatic food webs (Martin et al.,2004b; Houde et al., 2006; Li et al., 2008b), furthermore, posing po-tential risks to human health via the consumption of aquatic prod-ucts (Berger et al., 2009; Schuetze et al., 2010) due to the toxicitiesof these compounds (Lau et al., 2004; Shi et al., 2008). Earlier stud-ies indicated that sediment PFCs were likely originated from theeffluents of wastewater without efficient PFCs removal (Sinclairand Kannan, 2006; Yu et al., 2009), as a result, PFCs concentrationsof sediments downstream the river sections that received theseeffluents could be raised (Becker et al., 2008; Bao et al., 2009).Our previous research indicated that surface sediments might beobserved with higher concentrations of PFCs compared to the dee-per sediment cores (Bao et al., 2009). In addition, overall decreas-ing trends in PFCs concentrations along depth in differentsediment cores from various water bodies globally including lake,bay, and rivers were determined (Stock et al., 2007; Ahrens et al.,2009; Bao et al., 2009).

In the past three decades, rapid industrialization and urbani-zation took place throughout China, which made this countrybecome one of the world’s largest economies. The Pearl RiverDelta (PRD) and Yangtze River Delta (YRD) totally contributedto around 30% of annual China GDP. Financially, the economiesof highly developed metropolises of Shanghai in YRD andGuangzhou in PRD were evaluated to rank first and third,respectively, across the whole country (National Bureau of Sta-tistics of China, 2008). In general, the manufacturing activitiesof Shanghai relate to electricity and electronics, printing, petro-chemicals, chemical fabrics, textiles, as well as pulp and paper,while those of Guangzhou involve petrochemicals, electronicsand telecommunication, automatics and machinery, pharmaceu-ticals, and textiles. Demographically, Shanghai and Guangzhoupossessed urban populations of 12 million and 7 million, respec-tively, in the year of 2007 (National Bureau of Statistics ofChina, 2008). As a result of the booming economic and urbandevelopment, a range of environmental contaminations arisenfrom the POPs with respect to polycyclic aromatic hydrocarbons(PAHs) (Mai et al., 2002; Liu et al., 2008), polychlorinated biphe-nyls (PCBs) (Nie et al., 2005), polychlorinated dibenzo-p-dioxinsand/or dibenzofurans (PCDD/Fs) (Zhang et al., 2009), and poly-brominated diphenyl ethers (PBDEs) (Mai et al., 2005), havebeen determined in river sediments of Guangzhou and Shanghaiin the past several years, yet few studies have been carried onthe PFCs levels in urban river sediments from these two metrop-olises till now.

The present study aimed to demonstrate the spatial distribu-tions of PFCs levels in surface sediments from the Zhujiang Riverin Guangzhou and the Huangpu River in Shanghai, and to revealthe vertical variations of sediment PFCs with depth in these tworivers via the analysis on PFCs concentrations in sectioned sedi-ment cores from these two rivers, in addition, to determine themajor sediment PFC contaminant of each river relied on the per-centage contributions of PFCs in sediments of the two rivers. Thisstudy would be expected to provide useful information for legisla-tive initiatives or even controls on the PFCs contaminations in theZhujiang River and the Huangpu River in the future.

2. Materials and methods

2.1. Chemicals and equipments

Potassium heptadecafluorooctane sulfonate (PFOS, 98%) was ac-quired from Fluka (Steinheim, Germany). Potassium perfluorohex-ane sulfonate (PFHxS, 98%) was acquired from Interchim(Montlucon, France). Potassium nonafluoro-1-butanesulfonate(PFBS, 98%) and hepatadecafluoropelargonic acid (PFNA, 95%) wereacquired from Tokyo Chemical Industry (Tokyo, Japan). Pentadeca-fluorooctanoic acid (PFOA, 95%) was acquired from Wako PureChemical Industries (Osaka, Japan). Nonadecafluorodecanoic acid(PFDA, 96%) and perfluorododecanoic acid (PFDoA, 97%) wereacquired from Acros Organics (Geel, Belgium). Perfluorotetradeca-noic acid (PFTA, 97%) was acquired from Aldrich (Steinheim,Germany). Tetrabutylammonium hydrogensulfate (TBAHS) ofHPLC grade and anhydrous extra pure sodium carbonate (Na2CO3,99.5%) were obtained from Acros Organics (Geel, Belgium). HPLCgrade ammonium acetate was obtained from Dikma Technology(Richmond, VA). HPLC grade methyl tert-butyl ether (MTBE), meth-anol, and acetonitrile were obtained from Tedia (Fairfield, OH).Milli-Q water was cleaned using Waters Oasis HLB Plus cartridges(Milford, MA) to remove the potential residue of PFCs. Mixed stockPFCs standard solution was prepared in methanol. All reagentswere used as received. All the equipments involved in the wholestudy were pre-cleaned with methanol and subsequently cleanedMilli-Q water. Teflon and glass equipments were avoided.

2.2. Sampling area and collection

The sampling areas of this study involved the Zhujiang River inGuangzhou and the Huangpu River in Shanghai, respectively. AsFig. 1, the Zhujiang River with a length of 83 km and an averagedepth of 6.6 m, covering complicated waterways of the WestWaterway, the North Waterway, and the South Waterway con-necting to the Guanzhou and Lizong Waterways, etc., flowsthrough the central district of Guangzhou southeastwards intothe South Sea, while the Huangpu River is 114 km in length and9 m on average in depth, flowing northeast through the heart ofShanghai into the Yangtze River via a 60 km watercourse.

In March 2009, sampling campaigns for this study were carriedout at 22 sites in total, comprising 13 sites in the Zhujiang Riverand nine sites in the Huangpu River (Fig. 1). In one side, sites Z1–Z13 were located in the Zhujiang River, of which, sites Z1–Z3 were sit-uated in the West Waterway, sites Z4–Z7 were situated in the NorthWaterway, sites Z8 and Z9 were situated in the South Waterway, sitesZ10 and Z11 were located in the Guanzhou Waterway, and sites Z12and Z13 were located in the Lizong Waterway. In the other side, sitesH1–H9 were situated in the mainstream of the Huangpu River. All thesampling sites were planned in a range of 5–20 m off the riverbanksdepended on the width of the river. Two individual surface sedimentsof 2 cm in depth were collected with a hand piston sediment sampler(Ø = 6 cm) at each site and stored in polypropylene (PP) tubes. Twoadditional sediment cores with a depth of 60 cm each were also de-rived from sites Z1 and H9 with the sampler. The top 10 cm of thesetwo sediment cores were sectioned into 2 cm per slice, and then theremainder of each sediment core was sectioned into 10 cm per slicein situ. These slices were finally grouped into 250 mL PP bottles. Priorto each sampling, the sampler was pre-cleaned with methanol andsubsequently cleaned Milli-Q water conventionally.

2.3. Sample preparation and analysis

Sediments samples were transferred into PP boxes and air-dried, once arriving at the laboratory. Each dried sample was

Fig. 1. Sediment sampling area and sites in the Zhujiang River across Guangzhou and the Huangpu River across Shanghai.

J. Bao et al. / Chemosphere 80 (2010) 123–130 125

mixed and homogenized with a porcelain mortar and pestle, andthen sieved with a 0.83 mm mesh, finally stored at a 250 mL PPbottle under room temperature until the extraction.

The samples were extracted using the method described previ-ously (Bao et al., 2009). Briefly, 5 g of sediment was weighed into a50 mL PP tube, and then wet by adding 2 mL of cleaned Milli-Qwater with vortexing. Two milliliters of 0.25 M Na2CO3 and 1 mLof 0.5 M TBAHS solutions were added for extraction by vortexing.Subsequently, 5 mL of MTBE was added and shaken for 20 min.After centrifuging for 30 min at 3500 rpm, the supernatant wascollected. Five milliliters of MTBE was added into the remanentaqueous mixture again, followed by shaking and centrifuging, thesupernatant was combined with the first one in a 15 mL PP tube.The MTBE solvent was brought to dryness under a gentle stream

of high purity nitrogen, and reconstituted in 1 mL mixture of meth-anol and 10 mM ammonium acetate (2:3, v/v). The mixture was fil-tered through a 0.22 lm nylon filter, and then transferred into a1 mL PP snap top vial with polyethylene (PE) cap.

The extracts were analysed via high performance liquid chro-matography–tandem mass spectrometry (HPLC–MS/MS) system.An Agilent 1100 HPLC system (Agilent Technologies, Palo Alto,CA) was equipped with a 2.1 � 100 mm (3.5 lm) Agilent EclipsePlus C18 column (Agilent Technologies, Palo Alto, CA). The HPLCsystem was interfaced to an Agilent 6410 Triple Quadrupole(QQQ) mass spectrometer (Agilent Technologies, Santa Clara, CA)operated with electrospray ionization (ESI) in negative mode. De-tails of HPLC and MS/MS parameters for the instrumental analysiswere reported elsewhere (Bao et al., 2009).

126 J. Bao et al. / Chemosphere 80 (2010) 123–130

2.4. Quality assurance/quality control

Procedural blanks were prepared at an interval of every tensamples to check any potential contaminations occurred duringthe extraction of samples. Solvent blanks containing acetonitrileand cleaned Milli-Q water (2:3, v/v) were prepared to run afterevery seven samples for monitoring the instrumental background.

Table 1Spatial distributions of PFCs in river sediments from Guangzhou and Shanghai (ng/g dw)a

Location PFBS PFOS PFOA PFD

GuangzhouZ1 0.20 (15) 1.0 (14) 0.29 (5) <0.Z2 0.24 (19) 0.39 (9) 0.09 (30) n.dZ3 <0.10 0.51 (3) 0.24 (12) n.dZ4 0.32 (25) 3.1 (1) 0.20 (19) <0.Z5 0.11 (13) 0.85 (24) 0.22 (4) n.dZ6 0.24 (7) 1.2 (18) 0.28 (6) <0.Z7 n.d. n.d. 0.21 (5) n.dZ8 0.35 (8) 2.0 (10) 0.24 (1) 0.1Z9 0.35 (13) 1.1 (1) 0.25 (24) <0.Z10 <0.10 0.58 (6) 0.19 (18) n.dZ11 n.d. 0.43 (6) 0.20 (6) n.dZ12 n.d. n.d. 0.14 (10) n.dZ13 n.d. n.d. 0.09 (11) n.d

Median 0.11 0.58 0.21 0.0

ShanghaiH1 n.d. n.d. 0.41 (6) n.dH2 n.d. <0.12 0.44 (9) <0.H3 n.d. 0.15 (10) 0.47 (10) <0.H4 n.d. 0.16 (10) 0.64 (1) n.dH5 <0.10 0.46 (9) 0.53 (2) <0.H6 0.10 (4) n.d. 0.46 (6) <0.H7 n.d. <0.12 0.54 (1) <0.H8 n.d. n.d. 0.20 (6) n.dH9 n.d. n.d. 0.36 (12) n.d

Median 0.00 0.11 0.43 0.0

a Values in parentheses were %RSD (n = 2).b n.d. = not detected.

Fig. 2. Percentage contributions of PFCs in river

Duplicate samples and calibration check standards were run afterevery six samples to assure the precision and accuracy of eachrun. The concentrations of extracts were quantified via seven-pointmatrix-matched calibration curves constructed using externalstandards in the range of 0.05–50 ng/mL, which were generatedfrom a range of mixed PFCs standard solution diluted with theextracts of blank sediments (Bao et al., 2009). The regression

,b.

A PFDoAP

PFSAP

PFCAP

PFC

09 0.10 (3) 1.2 0.44 1.7. <0.09 0.63 0.14 0.77. n.d. 0.56 0.24 0.8009 n.d. 3.4 0.25 3.6. n.d. 0.96 0.22 1.209 n.d. 1.4 0.33 1.7. n.d. 0.00 0.21 0.211 (9) <0.09 2.3 0.40 2.709 <0.09 1.5 0.34 1.8. <0.09 0.63 0.24 0.87. n.d. 0.43 0.20 0.63. n.d. 0.00 0.14 0.14. n.d. 0.00 0.09 0.09

0 0.00 0.63 0.24 0.87

. n.d. 0.00 0.41 0.4109 n.d. 0.06 0.49 0.5509 0.10 (16) 0.15 0.62 0.77. <0.09 0.16 0.69 0.8509 n.d. 0.51 0.58 1.109 n.d. 0.10 0.51 0.6109 n.d. 0.06 0.59 0.65. <0.09 0.00 0.25 0.25. n.d. 0.00 0.36 0.36

4 0.00 0.13 0.45 0.71

sediments from Guangzhou and Shanghai.

J. Bao et al. / Chemosphere 80 (2010) 123–130 127

coefficients (r2) of calibration curves for all target analytes werehigher than 0.998. The limit of detection (LOD) was defined asthe peak of analyte that needed to yield a signal-to-noise (S/N) ra-tio of 3:1, while the limit of quantification (LOQ) was defined as thepeak of analyte that needed to yield a signal-to-noise (S/N) ratio of10:1 or the lowest point at calibration curve calculated to be with30% of its actual value. LODs ranged between 0.03 and 0.13 ng/gand LOQs ranged from 0.08 to 0.17 ng/g were determined for thePFCs analysis. Both recovery and reproducibility of the extractionwere validated by spiking 10 ng of each PFC standard onto 5 g sed-iment samples collected from the 50 to 60 cm section of site Z1 viaseven replicate analyses, the blank sediment samples were deter-mined as free of PFCs (Fig. 3).

2.5. Statistical analysis

Statistical analysis was performed with the software SPSS 16.0(SPSS Inc., Chicago, IL). During the analysis, all the analytical valuesthat lower than the LOQs were calculated using half of the LOQs,while those lower than the LODs were treated as zero, and meanvalue of two individual samples from the same location wasadopted. A Pearson rank correlation test was employed for assess-ment of correlation, since data concerned were determined to dis-tribute lognormally via a Kolmogorov–Smirnov test. Statisticalcorrelation and difference were considered to be significant atp < 0.05.

3. Results and discussion

According to the results from the quality assurance and qualitycontrol for this study mentioned above, it was shown that PFCs lev-els in all the procedural and solvent blanks were below the LODs.Recoveries of all the PFCs analytes were determined between81 ± 2% and 108 ± 3%, and relative standard deviation (RSD) foreach target analyte was lower than 5%.

In the present study, a total of eight PFCs were analysed in allthe sediment samples, whereas three of the analytes involvingPFHxS, PFNA, and PFTA in all of samples were lower than theirrespective LODs. As a result, concentrations of these three PFCswere not concerned in the discussion below.

3.1. Spatial distributions of PFCs in river sediments from Guangzhou

As Table 1, generally, total concentrations of PFCs (P

PFCs) insediments from the Zhujiang River across Guangzhou were rangedbetween 0.09 and 3.6 ng/g dry weight (dw). In detail, firstly, thehighest

PPFC in the North Waterway as well as the Zhujiang River

Fig. 3. Vertical variations of PFCs in sed

appeared in site Z4 with a concentration up to 3.6 ng/g dw; sec-ondly, the highest

PPFC in the South Waterway, which was the

second-rankedP

PFC in the Zhujiang River, showed in site Z8 witha concentration of 2.7 ng/g dw; finally, the highest

PPFC in the

West Waterway, which was the third-rankedP

PFC in the ZhujiangRiver, presented in site Z1 with a concentration of 1.7 ng/g dw. AsFig. 1, sites 4 and 8 were situated in the river sections by the con-ventional centre of Guangzhou, which would be possibly influ-enced by the discharge of municipal wastewater from the citycentre, while site 1 was located beside a wastewater treatmentplant served for the city centre, therefore the effluents of wastewa-ter could increase the PFCs levels in sediments around this site asstated previously (Becker et al., 2008; Bao et al., 2009). On the con-trary,

PPFCs of low levels were measured in site 7 of the North

Waterways and sites 12 and 13 of the Lizong Waterways, whichwere located in the river sections that away from the conventionalcity centre. Consequently, an overall decreasing trend along theflow direction of the river in sediment

PPFCs could be demon-

strated in the Zhujiang River (Table 1).As Fig. 2, PFOS was the dominant PFC contaminant detected in

all the sampling sites of the Zhujiang River except sites Z7, Z12 andZ13, where PFOA contributed 100% of all the target analytes. In theother ten sites, PFOS contributed 51–84% of the total PFCs for anal-ysis, however, relatively smaller contributions of PFOA were deter-mined between 5.5% and 31.7% of all the analytes. Comparable toPFOA, PFBS contributed 5.8–31.4% of the whole target analytes inthese locations. Overall, levels of PFOS were determined betweenbelow LOD and 3.1 ng/g dw with a median of 0.58 ng/g dw, whilethose of PFOA were ranged between 0.09 and 0.29 ng/g dw with amedian of 0.21 ng/g dw, and those of PFBS were detected from be-low LOD to 0.35 ng/g dw with a median of 0.11 ng/g dw. However,the concentrations of PFDA and PFDoA in sediments were mea-sured below their LOQs in most of the sampling sites. Total concen-trations of PFSAs (

PPFSAs) in sediments from the Zhujiang River

were thus determined significantly higher than total concentra-tions of PFCAs (

PPFCAs) in sediments there (p < 0.05). The highest

concentration of PFOS up to 3.1 ng/g dw appeared in site Z4 thatwas placed close to the conventional city centre as mentioned ear-lier. Nevertheless, PFOS contaminations were not observed in sitesZ7, Z12 and Z13, where PFOA was determined as the single PFCcontaminant.

Based upon the Pearson rank correlation analysis, sedimentPFOS concentrations of sites Z1–Z13 in the Zhujiang River werepresented to have a negative correlation with sediment PFOA con-centrations of these 13 sites in the river (r = �0.482, p = 0.013). AsTable 1, the PFOA concentrations in the Zhujiang River were com-parable in all the sites. Therefore, it was indicated that the PFOS

iment cores from sites Z1 and H9.

128 J. Bao et al. / Chemosphere 80 (2010) 123–130

contaminations in the upper reach of the Zhujiang River might behigher than those in the lower reach of the river. The concentra-tions of PFOS and PFBS in the river sediments from all the sam-plings sites were shown in a positive correlation (r = 0.509,p = 0.008), which indicated that these two PFCs contaminationsmight be originated from similar sources. It could be also explainedthrough that PFBS has come to be used as a key chemical inthe manufacture of materials to substitute for PFOS-based prod-ucts due to its low bioaccumulation in mammals, in recent years(Chengelis et al., 2009).

3.2. Spatial distributions of PFCs in river sediments from Shanghai

PPFCs in sediments from the Huangpu River across Shanghai

were ranged from 0.25 to 1.1 ng/g dw. The highestP

PFC in theHuangpu River appeared in site H5 with a concentration up to1.1 ng/g dw, subsequently the second- and third-ranked

PPFCs

with concentrations of 0.85 and 0.77 ng/g dw presented in sitesH4 and H3, respectively. As Fig. 1, these three sites were locatedin the reach by the Bund of Shanghai, which is the very central areaof this city. Similar to the Zhujiang River, potential wastewaterfrom the city centre would have an impact on the reach aroundthe Bund to some extent. Moreover, site H5 was situated in themouth of the Suzhou Creek, which has discharged enormous vol-ume of municipal wastewater receiving from urban areas of Shang-hai into the Huangpu River for a long period of time (Zeng et al.,2008). In general, the

PPFCs contaminations in sediments of the

Huangpu River were shown to have a tendency as follows, themore the locations closed to the Bund, the higher the levels ofP

PFCs were likely to be observed (Table 1).As the main PFC contaminant, PFOA contributed 48.8–100% of

the total PFCs analytes in all the sediments from the Huangpu Riv-er, while smaller contributions of PFOS were just determined be-tween 0% and 42% of all the analytes (Fig. 2), compared to thosedemonstrated in the Zhujiang River stated above. Specifically,PFOA concentrations presented in the range of 0.20–0.64 ng/g dwwith a median of 0.43 ng/g dw, while those of PFOS varied from be-low LOD to 0.46 ng/g dw with a median of 0.11 ng/g dw. The levelsof PFDA and PFDoA were detected below their LOQs in most of thesampling sites as those shown in the Zhujiang River, while PFBScontaminations that only monitored in two sites were quite differ-ent from those revealed in the Zhujiang River. As a result, sedimentP

PFCAs of Shanghai were proved to be significantly higher thansediment

PPFSAs there (p < 0.01). It was determined that site H4

had the highest concentration of sediment PFOA up to 0.64 ng/gdw, and the second highest contamination of sediment PFOA witha concentration of 0.53 ng/g dw occurred in site H5, where thehighest concentration of sediment PFOS up to 0.46 ng/g dw wasobserved. These two sites were positioned in the reach by the Bundas mentioned above. In addition, the Suzhou Creek seemed to be apotential source of PFOS for site H5, since this site was situated inthe creek mouth and the sediment PFOS level here varied consider-ably from those in the other sampling sites located in the main-stream (p < 0.01).

According to the results from the Pearson rank correlation anal-ysis, concentrations of PFOA in sediment from the sampling sitesH1–H9 were proved to have a significantly positive correlationwith concentrations of PFOS in sediments from these nine sites(r = 0.804, p = 0.000), which could result from the contaminationsof these two PFCs that shared related sources.

3.3. Vertical variations of PFCs in sediment cores

In the present study, vertical variations of PFCs with depth inthe two sediment cores from the Zhujiang River in Guangzhouand the Huangpu River in Shanghai each were investigated as de-

scribed previously (Bao et al., 2009). Based upon the analysis onsectioned sediment cores, an overall decreasing trend in sedimentP

PFCs along depth was illustrated in both the Zhujiang River andthe Huangpu River (Fig. 3) as reported by our previous study andother researchers (Stock et al., 2007; Ahrens et al., 2009; Baoet al., 2009).

In site Z1, as the dominant PFC contaminant, PFOS concentra-tion in the first slice of 0–2 cm was 0.95 ng/g dw, which showeda 1.14-fold increase compared to the average of 60 cm mixturewith a concentration of 0.44 ng/g dw. PFBS level in the first slicewith a concentration of 0.30 ng/g dw was 0.74-fold higher thanthe average of 0.17 ng/g dw, while PFOA level in this slice with acomparable concentration of 0.27 ng/g dw was just 0.39-fold high-er than the average of 0.20 ng/g dw. It was thus indicated that,firstly, release of PFOS around this site could be increased muchmore than those of PFBS and PFOA over there; secondly, PFBSwould have become another major PFCs contaminants locally fol-lowing PFOS and PFOA due to the increasing presence of this PFCin top sections of the sediment core, which might also supportthe percentage contributions of PFBS those determined in the PFCsof surface sediments from the Zhujiang River.

Different from the site above, PFOA was the exclusive PFC con-taminant measured in site H9, where PFOA concentration of0.16 ng/g dw in the first slice of 0–2 cm was significantly higherthan the average of 60 cm mixture that below the LOD, which dem-onstrated that a considerable increase in PFOA contaminationcould take place in the vicinity of this site. The absences of theother PFCs in this sediment core might be attributable to the dilu-tion of abundant water in river mouth as well as their relativelygreater water solubility compared to other POPs such as PCBsand DDT (Nakata et al., 2006).

3.4. Comparisons of sediment PFCs among various areas globally

Compared with the sediment PFCs determined in water bodiesaround the world, it was clear that the sediment PFOS contamina-tions with concentrations up to 3.1 ng/g dw in the Zhujiang Riverwere determined in a relatively higher levels than those reportedglobally so far (Table 2). While concentrations of sediment PFOSup to 0.46 ng/g dw in the Huangpu River were lower than those de-tected in the three rivers across the Central Liaoning City Cluster ofChina (Bao et al., 2009) as well as the three rivers across the SanFrancisco Bay Area of USA (Higgins et al., 2005), but higher thanthose measured in the Roter Main River through Bayreuth of Ger-many (Becker et al., 2008) and the Ariake Sea of Japan (Nakataet al., 2006).

As demonstrated in Table 2, levels of sediment PFOA up to0.64 ng/g dw in the Huangpu River were lower than those in theAriake Sea of Japan with the maximum concentration of 1.1 ng/gdw (Nakata et al., 2006), but comparatively higher than those inthe rivers reported worldwide up to now. Moreover, sedimentPFOA concentrations up to 0.29 ng/g dw in the Zhujiang River werecomparable to those observed in the three rivers across the CentralLiaoning City Cluster, China (Bao et al., 2009) and the three riversacross the San Francisco Bay Area, USA (Higgins et al., 2005), buthigher than those monitored in the Willamette River of Oregon,USA (Higgins et al., 2005) and the Roter Main River, Germany(Becker et al., 2008).

In summary, the present study revealed the spatial distributionsand vertical variations with depth of PFCs in the sediments fromthe Zhujiang River in Guangzhou and the Huangpu River in Shang-hai. Based upon the analysis above, some features of PFCs distribu-tions in sediments of the Zhujiang River and the Huangpu Rivercould be detailed as below, firstly, PFOS was the dominant PFC con-taminant in sediments from the Zhujiang River, while PFOA wasthe main PFC contaminant in sediments from the Huangpu River;

Table 2Comparisons of sediment PFCs among various areas globally.

Water body Location Depth of studied sediment Concentration of major PFC contaminant(ng/g dw)

Reference

PFOS PFOA

The Petaluma River;The Salinas River; The San Francisco 0–5 cm n.d. – 1.3 (1.2) n.d. – 0.23 (0.17) Higgins et al., 2005The San Lorenzo River; Bay Area, USA

The Willamette River Oregon, USA 0–5 cm n.d. 0.18 Higgins et al., 2005

The Ariake Sea Japan n.a. 0.09–0.14 (0.11) 0.84–1.1 (0.96) Nakata et al., 2006

The Roter Main River Bayreuth, Germany 0–15 cm 0.07–0.31 (0.24) 0.02–0.07 (0.04) Becker et al., 2008

The Hun River;The Taizi River The Central Liaoning City Cluster, China 0–1 cm 0.16–0.97 (0.29) 0.17–0.35 (0.30) Bao et al., 2009The Daliao River

The Zhujiang River Guangzhou, China 0–2 cm <0.12–3.1 (0.58) 0.09–0.29 (0.21) The present study

The Huangpu River Shanghai, China 0–2 cm <0.12–0.46 (0.11) 0.20–0.64 (0.43) The present study

n.d. = not detected; n.a. = not applicable; value in each parenthesis was the median determined in each of these studies.

J. Bao et al. / Chemosphere 80 (2010) 123–130 129

secondly, both the highest sedimentP

PFCs concentrations ofthese two rivers were determined in the river sections by the cen-tral areas of Guangzhou and Shanghai; finally, higher

PPFCs con-

taminations presented in the upper reaches of these two riverscompared to those in the lower reaches of these two rivers. In addi-tion, PFOS contaminations in sediments from the Zhujiang Riverand PFOA contaminations in sediments from the Huangpu Rivercould be considered to be more severe in comparison with othersediment PFCs contaminations within China reported so far. As aresult, it is recommended that further studies on the potential con-tamination sources of PFCs would be implemented within Guangz-hou and Shanghai for the purposes of controlling and preventingsediment PFCs contaminations in the Zhujiang River and the Hua-ngpu River prospectively.

Acknowledgements

This work is funded by the National Nature Science Foundationof China (No. 20837004) and also supported by the Program forChangjiang Scholars and Innovative Research Team in University(IRT 0813).

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