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Environmental Pollution 199 (2015) 102e109

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Environmental Pollution

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Are levels of perfluoroalkyl substances in soil related to urbanizationin rapidly developing coastal areas in North China?

Jing Meng a, b, Tieyu Wang a, *, Pei Wang a, b, Yueqing Zhang a, b, Qifeng Li a, b,Yonglong Lu a, John P. Giesy c

a State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, Chinab University of Chinese Academy of Sciences, Beijing 100049, Chinac Toxicology Centre and Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

a r t i c l e i n f o

Article history:Received 29 September 2014Received in revised form18 January 2015Accepted 20 January 2015Available online 30 January 2015

Keywords:PFASsSoilsUrbanizationSourcesBohai and Yellow Seas

* Corresponding author.E-mail address: wangty@rcees.ac.cn (T. Wang).

http://dx.doi.org/10.1016/j.envpol.2015.01.0220269-7491/© 2015 Elsevier Ltd. All rights reserved.

a b s t r a c t

Concentrations of 13 perfluoroalkyl substances (PFASs) were quantified in 79 surface soil samples from17 coastal cities in three provinces and one municipality along the Bohai and Yellow Seas. The

PPFASs

concentrations ranged from less than limitation of quantification (LOQ) to 13.97 ng/g dry weight (dw),with a mean of 0.98 ng/g dw. The highest concentration was observed along the Xiaoqing River fromShandong province, followed by that from the Haihe River in Tianjin (10.62 ng/g dw). Among four re-gions,

PPFASs concentrations decreased in the order of Tianjin, Shandong, Liaoning and Hebei, which

was consistent with levels of urbanization. Fluorine chemical industries allocated in Shandong andLiaoning played important roles in terms of point emission and contamination of PFASs, dominated byperfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Intensive anthropogenic activitiesinvolved in urbanization possibly resulted in increasing releases of PFASs from industrial and domesticsources.

© 2015 Elsevier Ltd. All rights reserved.

1. Introduction

Due to many desirable properties such as surface activity,thermal stability, acid resistance, and amphiphilicity (Kissa, 2001),perfluoroalkyl substances (PFASs) have been widely used as sur-factants and surface protectors in carpets, furniture, paper, foodcontainers, fabrics, and upholstery. They have also been applied asperformance chemicals in products such as fire-fighting foams,floor polishes, and shampoos (Giesy and Kannan, 2001). They arenow considered emerging pollutants, whose environmentalpersistency, bioaccumulation, global distribution and toxicity(Conder et al., 2008; Giesy et al., 2010; Schuetze et al., 2010; Zushiet al., 2010) have raised increasing concerns. PFASs were reportedto be widespread in the environment (Giesy and Kannan, 2001,2002) and subsequently detected in aquatic systems (Fujii et al.,2007; Rayne and Forest, 2009) and wildlife (Kannan et al., 2002;Houde et al., 2006; Fatihah et al., 2009). PFASs in soils can betransported to the atmosphere, surface water and groundwater

through volatilization, diffusion, leaching and mass flow (Armitageet al., 2009). Moreover, PFASs can biomagnify and accumulatethrough the food chain to wildlife and humans. The adverse effectsof PFASs on ecosystem and human health as well as secondaryrelease of PFASs from soil are still of long-term public concerns.Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid(PFOA), two predominant PFASs frequently detected in the envi-ronment, have received great attention in recent years. PFOS and itssalts have recently been listed as “persistent organic pollutants”(POPs) under the Stockholm Convention. However, exemptionswere made to allow their continued production and use in China(Wang et al., 2009b). China began large-scale production of PFOSand related chemicals in 2003. Before 2004, the total production ofPFOS and related chemicals in Chinawas less than 50 tons, whereasin 2006, fifteen Chinese enterprises produced a total of more than200 tons with 100 tons exported (Bao et al., 2009).

The coastal and estuarine areas of the Bohai and Yellow Seas,investigated in the present study, include seventeen coastal cities inTianjin, Hebei, Shandong, and Liaoning. The urbanization andindustrialization in the coastal regions are progressing dramaticallyalong with rapid economic development. These intensive anthro-pogenic activities have severely deteriorated environmental

Table 1QA/QC information of 13 PFASs including monitoring transitions (MT), limit ofdetection (LOD), limit of quantification (LOQ), matrix spike recovery (MSR) anddetection ratio.

Analyte MT LODng/g

LOQng/g

MSR % Detectedratioa (%)

Perfluorobutanoicacid (C4, PFBA)

213 / 169 0.05 0.05 100 ± 5 14 (18)

Perfluoropentanoicacid (C5, PFPeA)

263 / 219 0.01 0.03 104 ± 3 10 (13)

Perfluorohexanoicacid (C6, PFHxA)

313 / 269 0.01 0.01 110 ± 3 21 (27)

Perfluoroheptanoicacid (C7, PFHpA)

363 / 319 0.01 0.02 96 ± 6 20 (25)

Perfluorooctanoicacid (C8, PFOA)

413 / 369 0.05 0.05 100 ± 11 57 (72)

Perfluorononanoicacid (C9, PFNA)

463 / 419 0.05 0.05 109 ± 2 39 (49)

Perfluorodecanoicacid (C10, PFDA)

513 / 469 0.01 0.01 103 ± 7 33 (42)

Perfluoroundecanoicacid (C11, PFUdA)

563 / 519 0.01 0.02 90 ± 4 41 (52)

Perfluorododecanoicacid (C12, PFDoA)

613 / 569 0.01 0.01 89 ± 4 17 (22)

Perfluorobutanesulfonate (C4, PFBS)

299 / 99 0.05 0.05 119 ± 4 17 (22)

Perfluorohexanesulfonate (C6, PFHxS)

399 / 99 0.01 0.01 114 ± 8 0 (0)

Perfluorooctanesulfonate (C8, PFOS)

499 / 99 0.05 0.05 117 ± 2 49(62)

Perfluorodecanesulfonate(C10, PFDS)

599 / 99 0.01 0.02 86 ± 6 0 (0)

a Number of samples detected and % e occurrence in parenthesis given.

J. Meng et al. / Environmental Pollution 199 (2015) 102e109 103

quality, especially along the coast (Qiu et al., 2009; Tan et al., 2009).Emerging pollutants such as PFASs have become urgent environ-mental issues due to their extensive sources, high level of hazard,and difficulty of monitoring and controlling. Results of previousstudies indicated that emissions of PFOS were greater in more ur-banized eastern coastal regions of China (Xie et al., 2013a,b).Intensive industries including textile, printing and electroplatinghave led to releases of PFASs, especially those based on PFOS(Huang et al., 2010). The fluorine industry parks located in Liaoningand Shandong provinces have released PFASs (Wang et al., 2013,2014). Since 2008, we have been conducting systematic researchof organochlorine pesticides (OCPs), polycyclic aromatic hydrocar-bons (PAHs) and heavy metals in environmental matrices along theBohai Sea. It was found that industrialization and urbanizationwere strongly related to their pollution and distribution (Hu et al.,2010; Chen et al., 2011; Wang et al., 2011a). The Yellow River, HaiheRiver and Liaohe River systems are the most important watersources in this region, andmost of the river systems eventually flowinto the Bohai and Yellow Seas. Rapid economic development hasgenerated, and continues to generate increasing amounts ofmunicipal, industrial and agricultural wastes, which eventuallyaccumulate in the Bohai and Yellow Seas. Bohai Sea is currently oneof the most polluted seas in China (Zhang et al., 2006; Tan et al.,2009; Luo et al., 2010).

Our previous studies focused mainly on classic persistent toxicsubstances (PTS) such as heavy metals, PAHs, and OCPs in soils andsediments. PFASs in water were also reported (Hu et al., 2010; Luoet al., 2010; Chen et al., 2011;Wang et al., 2011b; Jiao et al., 2012). Inthis study, the concentrations and distribution of emerging pol-lutants PFASs were determined in soils from coastal and estuarineareas of the Bohai and Yellow Seas. The relationship between thePFASs concentrations in soil and the levels of urbanization was alsoanalyzed. Using a systematic approach, this studymay help identifypotential sources of pollutants and provide information for futuremanagement and soil remediation. There are currently very fewstudies of PFASs in soil. For the first time, we investigated spatialdistribution and potential sources of PFASs in soil samples takenfrom this rapidly developing coastal region.

2. Materials and methods

2.1. Sampling design and collection

The study area included three provinces and one municipalityalong the Bohai and Yellow Seas, i.e. Liaoning, Hebei, Tianjin andShandong. A total of seventy-nine surface soils were collected fromestuarine and coastal areas adjacent to the Bohai and Yellow Seas,including twenty-two from Liaoning, nine from Hebei, eight fromTianjin and forty from Shandong (Fig. S1). Surface (top 0e20 cm)soil samples were collected using a stainless steel trowel that hadbeen rinsed with methanol. Each sample was a composite of fivesub-samples (each weighed about 500 g) collected from the centerand four corners of an area of 100 � 100 m2. Sampling informationincluding location, land use and detailed description were sum-marized in Table S1. Samples were then transferred and stored inclean polypropylene (PP) bags. Duplicates and field blanks werecollected in each city and analyzed with laboratory and proceduralblanks. All samples were dried in air, homogenized with a porcelainmortar and pestle, sieved with a 2 mm mesh, and stored in250 mL PP bottles at room temperature until extraction.

2.2. Chemicals and reagents

The detailed descriptions on chemicals and reagents wereavailable in Supplementary Material.

2.3. Extraction and cleanup

PFASs were extracted using methods similar to those describedpreviously (Wang et al., 2013). Briefly, 2.5 g of sample was trans-ferred to a 50 mL PP tube, and moistened by 2 mL Milli-Q waterwith vortexing. Then 1 mL of 0.5 M TBAHS, 2 mL of 25 mM sodiumacetate and 1 ng mass-labeled internal standards (PFOA [1, 2, 3, 413C] and PFOS [18O2]) were added into the PP tube. The mixturewasshaken at 700 r/min for 5 min. Subsequently, 5 mL of MTBE wasadded and shaken for 20 min. After centrifuging for 20 min at 3500r/min, the supernatant MTBE was collected. This process wasrepeated twice which produced a final volume of 15 mL MTBEwash. The supernatant was evaporated to dryness under a gentleflow of high-purity nitrogen, and reconstituted in 1 mL methanol.The 1 mL elution was transferred to 50 mL PP tube, brought to50 mL with Milli-Q water and extracted with the SPE cartridge.

The SPE cartridge was preconditioned with 4 mL of 0.1%ammonia in methanol, 4 mL methanol and 4 mL Milli-Q water.50 mL sample was loaded into the cartridge. The cartridge waswashed with 20 mL Milli-Q water, 4 mL of 25 mM sodium acetate,allowed to run dry, and elutedwith 4mLmethanol and 4mL of 0.1%ammonia in methanol. The eluents were collected, combined, andconcentrated to 1 mL under a gentle stream of high purity nitrogenand then filtered through a 0.2 mm nylon filter into a 1.5 mL auto-sampler vial fitted with PP cap for HPLC analysis.

2.4. Instrumental analysis and quantitation

All PFASs were analyzed using an Agilent HP 1200 high perfor-mance liquid chromatography system (HPLC) equipped with anApplied Bioscience SCIEX 3000 tandem mass spectrometer (HPLC-MS/MS). Quantificationwas performed using Analyst 1.4.1 softwareprovided by SCIEX. The detailed descriptions on instrumental

J. Meng et al. / Environmental Pollution 199 (2015) 102e109104

analysis were available in Supplementary Material.

2.5. Quality control and quality assurance

For quality control and quality assurance, the use of Tefloncoated lab-ware was avoided during all steps of sample preparationand analysis to minimize contamination of the samples. Fieldblanks, laboratory blanks (including procedural blanks and solventblanks) and matrices spiked with the standard solution (2.0 ng/g dw) were analyzed. Procedural blanks using anhydrous sodiumsulfate in place of soil were analyzed with every set of samples andsolvent blanks using 100% methanol were run every 4e5 samplesto check for carryover and background contamination. Concentra-tions of all target PFASs in all field and laboratory blanks were lessthan the limit of detection (LOD), which was defined as 3 times ofsignal-to-noise ratio (S/N). And the limit of quantification (LOQ)was set as 5 times of S/N. Recoveries of PFASs were determined inthe range from 86 ± 6% to 119 ± 4%. Detailed QA/QC measurementsof PFASs in soil are given in Table 1.

2.6. Statistical analysis

All statistical analyses were performed with SPSS StatisticsV20.0 (SPSS Inc, USA). A statistical distribution test called PeP plotswas carried out to test the normal distribution of raw data in orderto ensure the data sufficient for further analysis (Fig. S2). Spatialdistributions of PFASs were analyzed using ArcGIS V10.0 (ESRI).

3. Results and discussion

3.1. Occurrence of soil PFASs and association with urbanization

Levels ofP

PFASs in soils from coastal and estuarine areas withdifferent urbanization levels along the Bohai and Yellow Seas aresummarized in Table 2. Urban population ratio, GDP per capita andtertiary industry ratio were collected to reflect the level of urban-ization of each city. Higher values of the three indices tended torepresent higher levels of urbanization (Chen et al., 2013).

Table 2Soil

PPFASs (ng/g dw) and urbanization levels in coastal and estuarine areas of the Boh

Province City Type of areaP

PFASs

Urban Suburban Rural PFOA PFOS

Liaoning Dandong 0.43(1)a eb 0.26(3) ndc ndDalian e e 0.12(4) nd ndYingkou 1.26(1) e 1.02(2) 0.08 0.26Panjin 0.23(1) e 0.23(1) 0.05 ndJinzhou 0.71(1) 0.41(1) 0.68(3) 0.21 0.01Huludao 0.33(1) 0.21(1) 1.20(2) 0.20 0.11Total 0.59(5) 0.31(2) 0.53(15) 0.10 0.06

Hebei Qinhuangdao 0.27(1) 0.39(1) 0.23(1) 0.09 ndTangshan e 0.03(2) 0.05(4) nd ndTotal 0.27(1) 0.15(3) 0.09(5) 0.03 nd

Tianjin Binhai 6.15(2) 6.98(1) 1.82(5) 0.41 1.88Total 6.15(2) 6.98(1) 1.82(5) 0.41 1.88

Shandong Dezhou 0.59(1) e 0.56(2) 0.25 0.15Binzhou e 0.94(2) 0.95(4) 0.58 0.11Dongying 0.40(2) e 3.50(5) 2.32 0.10Weifang 0.22(1) 0.85(1) 0.65(4) 0.33 0.12Yantai 0.44(3) 0.33(1) 0.48(9) 0.14 0.13Weihai e e 0.33(2) 0.06 0.11Qingdao e 0.34(1) 0.97(2) 0.26 0.17Total 0.41(7) 0.74(5) 1.11(28) 0.63 0.12

a Sample number in corresponding urbanization gradient.b No sample in corresponding urbanization gradient.c Not detectable, means concentration less than LOQ.

Commercial products were one of the important domestic sourcesof PFASs in cities (Xie et al., 2013a), and the urban population ratioand GDP per capita could be a surrogate for the extent of usage ofthese products. In general, urbanization of Tianjin was apparentlyhigher than that of the other three regions. Mean concentrations ofP

PFASs in the four regions were as follows: Tianjin (3.55 ng/g dw) > Shandong (0.93 ng/g dw) > Liaoning (0.52 ng/g dw) > Hebei (0.09 ng/g dw). Soil samples from Tianjin werecollected from Binhai district, which is one of the important in-dustrial regions with the most rapid development and relativelygreater level of urbanization. Concentrations of other pollutants,such as heavy metals, OCPs, and PAHs were relatively higher in thisregion as well (Luo et al., 2010; Wang et al., 2009a; Jiao et al., 2012).

Among the seven cities in Shandong province, the highestconcentration of

PPFASs was observed in Dongying, with a mean

of 2.60 ng/g dw. The GDP per capita of Dongying ($21,162) washigher than that of other cities as well. The secondary industrycontributed greatly to the higher GDP of Dongying, while its ter-tiary industry ratio (24.7%) was smaller as compared to other citiesin Shandong. The local dominant industries, including textile andpapermaking, might be the largest industrial sources of PFASs(Davis et al., 2007; Xie et al., 2013b). The highest concentration ofP

PFASs (13.97 ng/g dw) in all 79 soil samples was also observed inDongying, which further proved the impacts of textile and paper-making industries. Concentration of

PPFASs in soils from Binzhou

(0.91 ng/g dw) ranked the second. One of the largest Chinesechemical plants is situated in Binzhou, which discharges massivepollutants to the environment. Concentrations of

PPFASs from

Dongying and Binzhou were only lower than those from the Binhaidistrict of Tianjin, but higher than those from other cities. As thesecond largest city in Shandong province, Qingdao is highly ur-banized. The urban population ratio and tertiary industry ratio areas high as 63.1% and 47.8%, respectively. Concentrations of

PPFASs

in soils of Qingdao were relatively high, with a mean of 0.73 ng/g dw. Compared with Dongying and Binzhou, secondary industriescontributed a smaller proportion to pollution in Qingdao. However,intensive human activities possibly resulted in releases of PFASsfrom domestic sources such as packing materials, domestic

ai and Yellow Seas.

Indicator of urbanization

Total Urban populationratio (%)

GDP per capita (USD) Tertiary industry ratio (%)

0.30 43.0 5412 35.10.12 62.5 15368 41.51.10 48.2 7382 37.00.23 66.8 12074 22.80.63 40.5 5265 35.10.74 31.6 3632 37.20.520.30 41.6 5221 47.30.04 33.5 10529 31.00.093.55 71.7 40206 31.03.550.55 30.7 4985 33.90.91 37.7 7103 36.72.60 43.3 21162 24.70.59 52.4 5706 34.50.42 50.1 10338 34.90.31 51.4 12235 37.90.73 63.1 12691 47.80.93

J. Meng et al. / Environmental Pollution 199 (2015) 102e109 105

wastewater and daily commodities.In Liaoning province, soils were collected from six cities near the

Bohai Sea. Intensity of urbanization in Dalian was the greatest withan urban population ratio of 62.5% and a tertiary industry ratio of41.5%. Dalian is the pioneer city to adopt environmentally friendlyurban planning and strict environmental management. By adjust-ing industrial structures, heavy-polluting sections are constantlyeliminated and the proportion of chemical industry is decreasing.These activities resulted in lower concentrations of

PPFASs in

Dalian when compared with those of other coastal cities in Liaon-ing. In Liaoning province, the highest concentration of

PPFASs

(1.10 ng/g dw) was observed in Yingkou, one main area of theLiaohe River Basin. As a major water-receiving body, the LiaoheRiver system is influenced by sewage from the surrounding cities,and receives about 2 billion tons of industrial and domesticwastewater annually (Huang et al., 2012).

In Hebei, soils from Qinhuangdao and Tangshan, had relativelylower concentrations of

PPFASs, with mean values of 0.21 and

0.04 ng/g dw, respectively. Although Tangshan is an important in-dustrial city, dominated by the iron and steel industry, its industriesdo not cause as much PFAS pollution as the chemical industry.Generally, higher level of urbanization usually represents adecreasing industry ratio via the adjustment of industrial structure,and the pollution of PFASs usually reduces accordingly. Meanwhile,urban population increases with urbanization leading to domesticemissions of PFASs. However, the domestic sources of emissionaccount for only a small proportion (<10%) of the gross sources (Xieet al., 2013a,b).

3.2. PFASs in soils along the urbanization gradients

Spatial patterns of relative concentrations ofP

PFASs variedamong urban, suburban and rural areas, and among the four re-gions (Fig. 1). Proportions of

PPFASs in soils from the urban (39.0%)

and rural (36.4%) areas in Liaoning province were relatively higherthan those in suburban soils (24.6%). Liaoning is an important baseof the northeast traditional industries, currently at the transitionalstage of industrial development. Jinzhou and Huludao have beentwo cities with the most intensive chemical industry in China sincethe 1960s. There are still oil refining plants, chemical plants, andsmelting plants in these regions (Wang et al., 2011b). PFASs have

Fig. 1. Concentrations ofP

PFASs (ng/g dw) in soils along different urbanizationgradients.

been reported with higher concentrations in urban areas than inrural areas, which indicates that apart from industrial activities,releases from consumer products in urban areas are potentialsources of PFASs as well (Kim and Kannan, 2007; Ju et al., 2008).

Proportion ofP

PFASs in soils from Hebei province was greaterin urban (60.0%), than suburban (26.7%) or rural areas (13.3%), withmean concentrations of 0.27 ng/g dw, 0.12 ng/g dw and 0.06 ng/g dw, respectively. Hebei province has been relatively less urban-ized than the other three provinces. Most industries are still situ-ated in urban areas, and agricultural nonpoint source is still themain source in rural areas. Local industries are unlikely to causeserious pollution of PFASs, while domestic emission is also a mainsource comparing with other industrial regions.

Concentration ofP

PFASs was the highest (6.97 ng/g dw) in soilsof suburban area of Tianjin and a relatively higher mean concen-tration of 6.15 ng/g dw was observed in soils of urban area. Thesuburban area provides service facilities, e.g. wastewater treatmentplants, for the urban area, and many emerging industrial zones,especially for the high tech industries. The Tianjin Binhai district isone of the most important industrial areas in Northern China.Intensive economic development and urbanization in this areahave severely deteriorated environmental quality (Guo et al., 2011;Wang et al., 2011b). However, Shandong province exhibitedcompletely different distribution of PFASs. Rural soils had thehighest concentration of

PPFASs (1.11 ng/g dw, 49.1%), while the

proportions in urban and suburban soils were only 18.1% and 32.7%.Shandong is one of the fastest developing provinces. After intensivedevelopment of urban areas, more industries are moving from ur-ban to rural and/or suburban areas in order to obtain adequate andcheaper land and labors. This has led to the industrial emissions ofPFASs, which gradually become the main source of pollution inrural and suburban areas (Kim et al., 2012).

3.3. PFASs in soils along the coastal and estuarine rivers

For areas along the coastal and estuarine rivers adjacent to thenorth Bohai Sea, the highest concentration of

PPFASs (1.81 ng/

g dw) was observed in soil from Huludao (Fig. 2). The four detectedPFASs, including perfluorononanoic acid (PFNA), PFOA, per-fluoroundecanoic acid (PFUdA) and PFOS, had relatively similarconcentrations. The second highest concentration of

PPFASs was

1.26 ng/g dw, which was dominated by PFNA (0.96 ng/g dw). Thissite is located in the city of Yingkou and sample was collected fromthe estuary of the Liaohe River, which flows through the Bayuquandistrict of Yingkou. The Bayuquan district is one of the most rapidlydeveloping regions in the Liaodong Bay with several large indus-trial parks. The industries in these parks include textile, chemistry,machinery, home appliances, etc. Some PFASs may be released inthe production activities.

Soil samples along the five rivers adjacent to the Tianjin coastwere severely polluted. Concentrations of

PPFASs along these river

systems were as follows: Haihe River (6.16 ng/g dw) > YongdingRiver (3.83 ng/g dw) > Ziya River (2.07 ng/g dw) > Chaobai River(1.31 ng/g dw) > Duliujian River (1.27 ng/g dw). Haihe River wasfound to be one of the most polluted rivers in terms of PFASs orother pollutants (Luo et al., 2010; Wang et al., 2009a; Jiao et al.,2012; Li et al., 2011). The intense pollution was derived fromrapid development of the Beijing-Tianjin metropolitan region,especially the Tianjin Binhai district. The highest concentration ofP

PFASs (10.63 ng/g dw) was observed in the estuary of the HaiheRiver and the Bohai Bay, with a large contribution of 88.15% byPFOS. The Binhai district has been subjected to anthropogenic in-fluences as a result of rapid urbanization and industrialization. Therelatively great concentrations of

PPFASs indicated an input from

industrial effluent as well as atmospheric deposition. Furthermore,

Fig. 2. Spatial distributions of sample locations and related concentrations ofP

PFASs (ng/g dw) along coastal and estuarine areas of the Bohai and Yellow Seas.

J. Meng et al. / Environmental Pollution 199 (2015) 102e109106

the Haihe Watershed contains a variety of industries includingchemical and biochemical products manufacturing, and receivesindustrial and domestic discharges mainly from Tianjin and Beijing.

For samples of soils along the coastal and estuarine riversadjacent to the south Bohai Sea and Yellow Sea, mainly fromShandong province, the concentrations of

PPFASs along the

Xiaoqing River (5.53 ng/g dw), Tuhai River (1.25 ng/g dw), ShaheRiver (0.98 ng/g dw) and Jiaolai River (0.98 ng/g dw) were higherthan those along the other 14 rivers. The Xiaoqing, Shahe and JiaolaiRivers flow into the Laizhou Bay and contribute greatly to pollution.The most severely polluted area occurred in the downstream of theXiaoqing River, with a concentration of 13.97 ng/g dw. PFOA wasthe dominant pollutant and accounted for more than 98.7% ofP

PFASs. PFOA is used as the surfactant in the treatment of paperand textile and directly causes serious pollution locally. Simulta-neous investigation indicated that facilities along the XiaoqingRiver and its tributaries exhibited the greatest emissions of wastes(Wang et al., 2014; Zhu et al., 2014). However, samples of soil andother media such as water and sediments could not be collecteddirectly from the manufacturing facilities to verify the presumedsource of PFOA. Therefore, more research is needed to determine itsexact origin.

3.4. Patterns of relative concentrations ofP

PFASs in soils

The compositions ofP

PFASs in soils along the coast and estuaryof the Bohai and Yellow Seas are summarized in Fig. 3. The com-positions of the four regions were completely different. Generally,PFOA and PFOS were the dominant PFASs. Other detected PFASswere mainly longer-chain perfluorocarboxylic acids (PFCAs),including PFNA, PFUdA and perfluorododecanoic acid (PFDoA).

Longer-chain PFCAs are more easily adsorbed to solids (Higginset al., 2005; Li et al., 2010). In Liaoning province, PFNA and PFUdAcontributed 39.1% and 30.8% of

PPFASs, respectively, while PFOS

and PFOA only accounted for 12.9% and 17.2%, respectively. While inHebei province, only longer-chain PFCAs such as PFOA, PFNA andPFUdA, were detected. In this region, releases of PFASs were mainlyfrom domestic products. In the Tianjin municipal region, PFOSaccounted for 53.1% of

PPFASs. In general, PFOS is derived from

industrial emission, indicating that factories in Tianjin dischargedrelatively large amounts of PFOS. In addition, PFOA, PFUdA andPFDoA accounted for approximately half of the concentration ofP

PFASs. In Shandong province, PFOA (66.3%) and PFOS (13.2%)were the major components of

PPFASs, especially PFOA. The

greater detection ratio of PFOA was mainly contributed by pollut-ants from the Xiaoqing River. Meanwhile, other PFASs weredetected in Tianjin and Shandong, which were released fromdifferent types of industries, especially chemical industry. The dif-ference among the four regions revealed that the pollution wasmainly caused by industrial sources, because there was not muchdifference in domestic sources under current urbanization.

In terms of urbanization gradients, the detected PFASs weremostly consistent in the same region, but the proportions weredistinct among the three gradients of urbanization. Major in-dustries caused the differences among the four regions. The loca-tions of these factories led to the differences among urban,suburban and rural areas. In Tianjin and Shandong, concentrationsof PFOS decreased from urban, to suburban to rural areas, butconcentrations of PFOA increased along the same gradient. Thetrend of PFOS indicated that chemical industry was the primarysource. However, the increased trend of PFOA in Shandong wasmainly caused by the increasing number of papermaking and

Fig. 3. Compositions of individual PFASs in soils according to urbanization and river.

J. Meng et al. / Environmental Pollution 199 (2015) 102e109 107

textile factories.The most important source of contaminants in soils along rivers

is irrigation with river water. Polluted rivers are likely to increasethe contamination of soils. Thus, investigation of PFASs in soilscould be useful for a long-term, integrative measure of the status ofPFASs in rivers (Naile et al., 2010; Wang et al., 2011b; Meng et al.,2013). Concentrations of PFASs in rivers are mainly derived fromupstream regions of rivers and surrounding domestic and indus-trial sources. Transport of PFASs along rivers in Shandong was themost obvious, which can be exemplified by the variation of PFOAand PFOS. This indicated the contribution of PFASs from upstream.Contributions of PFASs from upstream areas in Liaoning, Hebei and

Fig. 4. Concentrations ofP

PFASs (ng/g dw) in soils under different land uses.

Tianjin were relatively smaller than the surrounding sources.

3.5. PFASs in soils under different land uses

Soil samples were classified into six groups according to landuse, including grain (n ¼ 27), grass (n ¼ 13), barren (n ¼ 18), woods(n ¼ 11), cotton (n ¼ 7) and fruit (n ¼ 3) (Table S5). Concentrationsof

PPFASs in soils under different land uses showed obvious dif-

ference (Fig. 4). In Tianjin,P

PFASs (6.16 ng/g dw) in barren landwere the highest, followed by

PPFASs in grassland (3.09 ng/g dw).

These barren lands were located in surroundings of factories, so theindustrial emissions may be the main contributor.

PPFASs in

grassland were detected with much higher levels in Liaoning(0.71 ng/g dw) and Shandong (2.11 ng/g dw).

PPFASs in grain land

(nd-2.07 ng/g dw) and wood land (nd-2.51 ng/g dw) showedsimilar levels in the four regions. The relatively low

PPFASs levels

in most grain lands (with the exception of those from the HaiheRiver and the Xiaoqing River) indicated no serious pollution to foodsource. Therefore, it is necessary to change the type of land use orprohibit river irrigation at these sites with relatively high levels ofP

PFASs. Cotton soils and fruit soils were only collected in Shan-dong.

PPFASs from the two different lands were 0.93 and 0.42 ng/

g dw, respectively.

4. Conclusion

The urbanization and industrialization in the coastal region aregrowing dramatically along with the rapid economic developmentin China. As a result, emerging pollutants such as PFASs produced inthe processes of production and consumption, have become newand urgent environmental issues. Plenty of old industrial areascoexist with rapidly urbanized areas along the coastal region of the

J. Meng et al. / Environmental Pollution 199 (2015) 102e109108

Bohai and Yellow Seas, which result in increasing pollution ofPFASs. PFASs in soils from Tianjin and Shandong with higher levelsof urbanization showed relatively higher concentrations. With thedevelopment of urbanization, factories are constantly moving fromurban areas to rural areas, which can raise emission of PFASs inrural areas as well. Rural areas, being important bases for cropproduction, deserve more attention. In general, PFOA and PFOSwere the dominant PFASs in the studied area, especially in Tianjinand Shandong. PFOS was mainly emitted from chemical plants, andPFOA mainly came from paper-making and textile industries. Thisstudy would provide valuable information for management andcontrol of the emerging pollutants in the rapidly developing coastalregion. Further detailed work with more intensive sampling effortover time is recommended to identify any shifts in production toshorter chained or lesser fluorinated PFASs. Such approach wouldhelp identify trends and sources, and evaluate control measures toreduce soil and riverine discharge of PFASs into the coastal andmarine ecosystem.

Acknowledgments

This study was supported by the National Natural ScienceFoundation of China under Grant No. 41171394 and 41371488, theNational Fundamental Field Study Program with Grant No.2013FY11110, and the Key Research Program of the Chinese Acad-emy of Sciences under Grant No. KZZD-EW-TZ-12. Prof. Giesy wassupported by the Canada Research Chair Program and the EinsteinProfessor Program of the Chinese Academy of Sciences. Finally, wewould like to thank the editors and reviewers for their valuablecomments and suggestions.

Appendix A. Supplementary data

Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.envpol.2015.01.022.

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<Supplemental Materials>

Are levels of perfluoroalkyl substances in soil related to urbanization

in rapidly developing coastal areas in North China?

Tieyu Wang 1*, Jing Meng 1,2, Pei Wang 1,2, Yueqing Zhang 1,2, Qifeng Li 1,2,

Yonglong Lu1, John P. Giesy3

1. State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental

Sciences, Chinese Academy of Sciences, Beijing 100085, China;

2. University of Chinese Academy of Sciences, Beijing 100049, China;

3. Toxicology Centre and Department of Veterinary Biomedical Sciences, University of

Saskatchewan, Saskatoon, Saskatchewan, Canada

* Corresponding author:

* Tieyu Wang

Tel: +86 10 62849466; Fax: +86 10 62918177

E-mail address: wangty@rcees.ac.cn (T. Wang)

Details of materials and methods

Chemicals and reagents

The external standards of 13 PFASs, including perfluorobutanoic acid (PFBA),

perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA),

perfluoroheptanoic acid (PFHpA), PFOA, perfluorononanoic acid (PFNA),

perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA),

perfluorododecanoic acid (PFDoA), perfluorobutane sulfonate (PFBS),

perfluorohexane sulfonate (PFHxS), PFOS, perfluorodecane sulfonate (PFDS), and

the international standard consisted with PFOA [1, 2, 3, 4 13C] and PFOS [18O2] had

purities of >98% (Wellington Laboratories, Canada). HPLC grade methanol,

tetrabutylammonium hydrogensulfate (TBAHS), methyl tert-butyl ether (MTBE),

ammonium acetate and ammonium acetate were purchased from J.T. Baker

(Phillipsburg, NJ, USA). Milli-Q water was obtained from a Milli-Q gradient A-10

(Millipore, Bedford, MA, USA).

Instrumental analysis and quantitation

A 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 Aglient ZORBAX Eclipse Plus C18 (2.1×100 mm, 3.5 μm particle size) analytical

column, and a suitable guard column (Agilent 1290 Infinity In-line filter with 0.3μm

SS frit) was used to prevent instrument background contamination. An aliquant of 2

mM ammonium acetate as an ionization aid and methanol were used as mobile phases.

Gradient conditions were used at 300 μl/min flow rate and 10 μl of the sample was

injected, starting with 60% A (2 mM ammonium acetate) and 20% B (100%

methanol). Initial conditions were held for 2 min and then ramped to 20% A at 18 min,

held till 20 min, decreased to 0% A at 21 min, increased to 100% A at 22 min, held

until 22.5 min, returned to initial condition at 23 min, and finally held constant until

26 min. The temperature of the column oven was kept constant at 35 ℃.

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 using a multiple

reaction monitoring mode (MRM) with a dwell time of 40 ms. The following

instrument parameters were used: desolvation temperature (450 ℃), desolvation

(curtain) gas 6.0 arbitrary units (AU); nebulizer gas flow 5 AU; ion spray voltage

-3500 V; and collision gas 12 AU. The optimal settings for collision energies and

declustering potential were determined for each analyte’s transitions. Quantification

using these transitions was performed using Analyst 1.4.1 software provided by

SCIEX (Applied Bioscience, Foster City, CA).

Table S1 Sampling information including location, landuse and detailed description Site Province City River Type of area Landuse Characteristics

DD1 Liaoning Dandong Dayang River Rural Grass Close to wetland, agricultural filed nearby

DD2 Yalu River Urban Grain Small park nearby, Yalu River

DD3 Yalu River Rural Grain Downstream of industrial plants, rice field

DD4 Yalu River Rural Barren Open land for future development

DL1 Dalian Fuzhou River Rural Grass Changxing Island, yellow soil

DL2 Fuzhou River Rural Woods Women washed cloths nearby, no industry

DL3 Biliu River Rural Woods Sandy soil, no point sources

DL4 Beach Rural Grain Potato field, salt or shrimp ponds nearby

HL1 Huludao Liugu River Suburban Grain Newly planted corn, lots of trash nearby

HL2 Liugu River Rural Grain Freshly tilled, corn field

HL3 Wuli River Urban Grain Newly planted corn, lots of mining and coal plants nearby

HL4 Beach Rural Grass Close to harbor, on cliff

JZ1 Jinzhou Xiaoling River Rural Grain Corn field, close to salt/shrimp ponds

JZ2 Xiaoling River Urban Grass Dark brown soil, river flows through Jinzhou City

JZ3 Daling River Rural Grain Daling River, corn field, close to one busy bridge

JZ4 Daling River Suburban Grain Daling River, steel factory nearby, light brown soil, corn field

JZ5 Daling River Rural Grain Mouth of Daling River, lots of oil wells nearby, corn field

PJ1 Panjin Beach Urban Grain Paper plant in the upstream, rice field

PJ2 Beach Rural Barren Close to open sea

YK1 Yingkou Daliao River Rural Woods Midstream of Daliao River, some large housing projects

YK2 Daliao River Urban Woods Mouth of Daliao River, red soil

YK3 Erdao River Rural Grain Bayuquan District, chemical plant in the south

QH1 Hebei Qinhuangdao Beach Suburban Grass Sandy, long grass covering

QH2 Beach Urban Barren Close to beach

QH3 Qinglong River Rural Barren Sandy, close to a dam

TS1 Tangshan Dou River Suburban Grain Agricultural field, newly tilled, small river nearby

TS2 Shuanglong River Suburban Grain Rice field, soils was turned over, small river

TS3 Shuanglong River Rural Barren Salty soil, no factories

TS4 Luan River Rural Barren Close to harbor, sandy soil

TS5 Luan River Rural Barren Sandy soil

TS6 Luan River Rural Grain Close to highway

TB1 Tianjin Binhai New Area Chaobai River Rural Barren Near to high-tech industrial park

TB2 Yongding River Rural Woods Near to a reservoir

TB3 Yongding River Rural Barren Riverside, abandoned land

TB4 Yongding River Suburban Barren Coastal area, vicinity of oil plant

TB5 Haihe River Urban Barren Sewage drainage, near chem-industrial plant

TB6 Haihe River Urban Barren Coastal area, inside of harbor

TB7 Duliujian River Rural Barren Coastal area, near to garment factories

TB8 Ziya River Rural Grain Coastal area, near to oil production plant

DZ1 Shandong Dezhou Majia River Urban Grain Drinking water source

DZ2 Zhangweixin River Rural Cotton Famous large chemical plant nearby

DZ3 Zhangweixin River Rural Grain Many chemical plants and paper mills in the south

BZ1 Binzhou Zhangweixin River Rural Barren Clay soil, lots of biological residues

BZ2 Majia River Rural Cotton One leather factory in the west

BZ3 Tuhai River Rural Cotton Two factories, a variety of species nearby

BZ4 Tuhai River Suburban Woods There is one domestic wastewater drain

BZ5 Yellow River Rural Woods Sandy soil, no industry nearby

BZ6 Yellow River Suburban Grain Close to Yellow River Ecological Garden

DY1 Dongying Yellow River Suburban Cotton Plastic mulch

DY2 Yellow River Suburban Grain Mainly green belts on both sides of Yellow River

DY3 Yellow River Rural Cotton Lots of dead plant roots in soil

DY4 Yellow River Rural Grass Located in Yellow River Estuary Wetland, good protection

DY5 Xiaoqing River Rural Grass Sandy soil, large salt field nearby

DY6 Xiaoqing River Rural Cotton Plastic mulch, one large factory nearby

DY7 Xiaoqing River Rural Grass Lots of chemical plants and paper mills

WF1 Weifang Mi River Urban Barren A scene of desolation nearby

WF2 Mi River Rural Grass Sandy soil, one paper mill in the upstream

WF3 Mi River Rural Barren Lots of chemical plants

WF4 Wei River Rural Cotton Sandy soil, one industrial plant on the east coast

WF5 Wei River Suburban Woods Household garbage on the shore

WF6 Wei River Rural Woods One dam in the upstream

YT1 Yantai Sha River Rural Grain Salt fields nearby

YT2 Sha River Rural Grass One reservoir in the upstream

YT3 Wang River Rural Grain Local people directly use river water to wash clothes, no pollution

YT4 Wang River Rural Grass There are one factory and one industrial park in the south

YT5 Jie River Rural Woods Lush herbage and poplar, one factory in the northeast

YT6 Jie River Suburban Grass One leather factory nearby, acid smell in the air

YT7 Huangshui River Rural Fruit One reservoir in the upstream, no pollution

YT8 Huangshui River Rural Grass There is one dam in the upstream

YT9 Pingchang River Rural Woods Green belts on both sides of Pingchang River

YT10 Jia River Urban Barren Lots of factories nearby

YT11 Jia River Urban Fruit One dam in the upstream, bad smell in the air

YT12 Jia River Urban Fruit One sewage outlet in the upstream, lots of household garbage

YT13 Wulong River Rural Grain Large fishing and dredging activities

WH1 Weihai Wuzhu River Rural Grain A variety of crops, no industrial pollution

WH2 Duo River Rural Grain One pesticide factory nearby, pesticide pollution

QD1 Qingdao Jiaolai River Rural Grain Chemical plants and leather factories in the north

QD2 Jiaolai River Rural Grain One dam in the upstream

QD3 Moshui River Suburban Barren Barren soil on the river bank

Table S2 Concentrations of ∑PFASs in soils along coastal and estuarine rivers of the Bohai Sea (ng/g dw)

Site PFBA PFPeA PFHxA PFHpA PFOA PFNA PFDA PFUdA PFDoA PFBS PFOS ∑PFASs

DD1 nda nd nd nd nd 0.40 nd nd nd nd nd 0.40 DD2 nd nd nd nd nd 0.28 nd 0.15 nd nd nd 0.43 DD3 nd nd nd nd nd 0.09 nd 0.29 nd nd nd 0.38 DD4 nd nd nd nd nd nd nd nd nd nd nd nd DL1 nd nd nd nd nd nd nd nd nd nd nd nd DL2 nd nd nd nd nd nd nd nd nd nd nd nd DL3 nd nd nd nd nd 0.28 0.03 0.03 nd nd nd 0.34 DL4 nd nd nd nd nd 0.14 nd nd nd nd nd 0.14 HL1 nd nd nd nd 0.07 nd nd 0.26 nd nd nd 0.33 HL2 nd nd nd nd 0.09 0.08 nd 0.42 nd nd nd 0.59 HL3 nd nd nd nd 0.16 nd nd 0.05 nd nd nd 0.21 HL4 nd nd nd 0.06 0.47 0.43 0.02 0.37 nd nd 0.46 1.81 JZ1 nd nd nd nd 0.14 0.45 nd 0.28 nd nd nd 0.87 JZ2 nd nd nd nd 0.18 0.22 nd 0.31 nd nd nd 0.71 JZ3 nd nd nd nd 0.50 0.16 0.06 0.39 nd nd 0.06 1.17 JZ4 nd nd nd nd 0.21 0.07 nd 0.13 nd nd nd 0.41 JZ5 nd nd nd nd nd nd nd nd nd nd nd nd PJ1 nd nd nd nd nd 0.21 nd 0.02 nd nd nd 0.23 PJ2 nd nd nd nd 0.10 0.13 nd nd nd nd nd 0.23 YK1 nd nd nd 0.02 0.17 0.20 nd 0.15 nd 0.25 0.09 0.88 YK2 nd nd nd nd 0.07 0.96 nd 0.23 nd nd nd 1.26 YK3 nd nd nd nd nd 0.34 0.08 nd 0.04 nd 0.70 1.16 QH1 nd nd nd nd 0.14 0.23 nd 0.02 nd nd nd 0.39

QH2 nd nd nd nd nd 0.27 nd nd nd nd nd 0.27 QH3 nd nd nd nd 0.14 0.05 nd 0.04 nd nd nd 0.23 TS1 nd nd nd nd nd nd nd nd nd nd nd nd TS2 nd nd nd nd nd 0.05 nd nd nd nd nd 0.05 TS3 nd nd nd nd nd 0.10 nd nd nd nd nd 0.10 TS4 nd nd nd nd nd nd nd nd nd nd nd nd TS5 nd nd nd nd nd nd nd nd nd nd nd nd TS6 nd nd nd nd nd nd 0.01 0.07 nd nd nd 0.08 TB1 nd nd nd nd nd nd 0.06 0.94 0.26 nd nd 1.26 TB2 nd nd nd 0.10 0.46 0.08 0.84 0.39 0.42 nd 0.21 2.50 TB3 nd nd nd nd 0.41 nd nd 1.01 0.46 nd 0.14 2.02 TB4 nd nd nd nd 0.63 nd 0.18 0.82 0.61 nd 4.74 6.98 TB5 nd nd nd nd 0.93 nd 0.06 nd 0.26 nd 9.37 10.62 TB6 nd nd nd nd 0.26 nd nd 0.57 0.43 nd 0.42 1.68 TB7 nd nd nd 0.09 0.15 nd nd 0.54 0.47 nd nd 1.25 TB8 nd nd nd 0.10 0.43 nd 0.29 0.70 0.39 nd 0.16 2.07 DZ1 nd 0.03 0.03 0.02 0.26 0.06 0.02 nd nd 0.05 0.12 0.59 DZ2 nd nd 0.02 nd 0.21 nd nd nd nd nd 0.21 0.44 DZ3 nd nd nd nd 0.29 0.08 0.04 0.03 nd 0.05 0.12 0.61 BZ1 nd nd nd nd 0.05 nd nd nd nd nd nd 0.05 BZ2 nd 0.03 0.04 0.05 0.68 0.12 0.04 0.04 0.01 0.06 0.23 1.30 BZ3 nd 0.04 0.07 0.06 1.29 0.06 0.02 0.02 nd 0.05 0.11 1.72 BZ4 nd 0.04 0.04 0.02 0.40 0.05 0.04 0.05 nd nd 0.07 0.71 BZ5 nd nd 0.04 0.03 0.29 nd 0.02 nd nd 0.06 0.13 0.57 BZ6 nd 0.04 0.05 0.05 0.78 nd nd nd nd 0.08 0.09 1.09 DY1 nd nd 0.02 nd 0.34 nd nd nd nd 0.06 0.07 0.49

DY2 nd nd nd nd 0.16 nd nd nd nd 0.06 0.05 0.27 DY3 nd 0.05 nd nd 0.24 nd nd nd nd 0.06 0.18 0.53 DY4 nd nd nd nd 0.18 nd nd nd nd 0.06 0.11 0.35 DY5 nd nd nd nd 0.40 0.06 0.05 0.02 nd nd 0.09 0.62 DY6 nd 0.07 0.03 nd 1.63 0.06 0.03 0.02 nd 0.05 0.08 1.97 DY7 0.13 0.05 0.05 0.04 13.30 0.10 0.06 0.04 0.02 0.06 0.12 13.97 WF1 nd nd nd nd 0.07 nd nd nd nd 0.06 0.09 0.22 WF2 nd nd nd nd 0.26 nd nd nd nd 0.05 0.06 0.37 WF3 nd nd nd nd 0.60 nd nd nd nd 0.05 0.24 0.89 WF4 nd 0.04 0.02 0.02 0.46 0.07 0.04 0.03 nd nd 0.09 0.77 WF5 0.12 nd 0.03 0.05 0.43 0.05 0.02 nd nd nd 0.14 0.84 WF6 0.15 nd 0.02 nd 0.15 nd nd nd nd nd 0.12 0.44 YT1 0.12 nd 0.05 0.07 0.67 0.10 0.05 0.03 0.02 nd 0.13 1.24 YT2 0.13 nd 0.02 0.02 0.25 0.07 0.03 0.02 nd nd 0.14 0.68 YT3 0.12 nd nd nd 0.11 nd 0.02 0.02 0.01 nd 0.15 0.43 YT4 0.11 nd nd nd nd nd nd nd nd nd 0.08 0.19 YT5 nd nd nd nd 0.17 nd nd nd nd nd 0.15 0.32 YT6 0.10 nd nd nd 0.08 nd 0.02 nd nd nd 0.09 0.29 YT7 nd nd 0.10 nd nd nd 0.02 0.02 nd nd 0.12 0.26 YT8 0.12 nd 0.02 nd nd nd nd nd nd nd 0.10 0.24 YT9 nd nd nd nd 0.09 nd nd nd nd nd 0.12 0.21 YT10 nd nd nd nd 0.10 0.05 0.02 nd nd nd 0.18 0.35 YT11 nd nd nd nd 0.08 nd nd nd nd nd 0.12 0.2 YT12 0.20 nd 0.01 0.02 0.12 0.06 0.02 0.03 0.01 0.05 0.15 0.67 YT13 0.12 nd nd nd 0.10 0.07 0.02 0.03 nd nd 0.10 0.44 WH1 0.12 nd nd nd 0.06 0.05 0.06 0.04 0.01 nd 0.12 0.46

WH2 nd nd nd nd 0.05 nd nd nd nd nd 0.10 0.15 QD1 0.13 nd 0.03 0.03 0.25 0.06 0.04 0.04 0.02 nd 0.19 0.79 QD2 0.14 0.03 0.05 0.05 0.43 0.10 0.04 0.04 0.01 nd 0.22 1.11 QD3 nd nd 0.03 0.03 0.12 nd 0.02 nd nd nd 0.10 0.30

a: not detectable, means concentration less than LOQ

Table S3 Concentrations of individual PFASs in soils from 16 coastal cities in the Bohai Economic Rim Province City PFBA PFPeA PFHxA PFHpA PFOA PFNA PFDA PFUdA PFDoA PFBS PFOS ∑PFASs Liaoning Dandong nd nd nd nd nd 0.19 nd 0.11 nd nd nd 0.30 Dalian nd nd nd nd nd 0.11 0.01 0.01 nd nd nd 0.12 Yingkou nd nd nd 0.01 0.08 0.50 0.03 0.13 0.01 0.08 0.26 1.10 Panjin nd nd nd nd 0.05 0.17 nd 0.01 nd nd nd 0.23 Jinzhou nd nd nd nd 0.21 0.18 0.01 0.22 nd nd 0.01 0.63 Huludao nd nd nd 0.02 0.20 0.13 nd 0.28 nd nd 0.11 0.74 Total nd nd nd nd 0.10 0.20 0.01 0.14 nd 0.01 0.06 0.52 Hebei Qinhuangdao nd nd nd nd 0.09 0.18 nd 0.02 nd nd nd 0.30 Tangshan nd nd nd nd nd 0.03 nd 0.01 nd nd nd 0.04 Total nd nd nd nd 0.03 0.05 nd 0.01 nd nd nd 0.09 Tianjin Binhai nd nd nd 0.04 0.41 0.01 0.18 0.62 0.41 nd 1.88 3.55 Total nd nd nd 0.04 0.41 0.01 0.18 0.62 0.41 nd 1.88 3.55 Shandong Dezhou nd 0.01 0.02 0.01 0.25 0.05 0.02 0.01 nd 0.03 0.15 0.55 Binzhou nd 0.03 0.06 0.04 0.58 0.04 0.02 0.02 nd 0.04 0.11 0.91 Dongying 0.02 0.02 0.01 0.01 2.32 0.03 0.02 0.01 nd 0.05 0.10 2.60 Weifang 0.05 0.01 0.01 0.01 0.33 0.02 0.01 nd nd 0.03 0.12 0.59 Yantai 0.08 nd 0.02 0.01 0.14 0.03 0.02 0.01 nd nd 0.13 0.42 Weihai 0.06 nd nd nd 0.06 0.03 0.03 0.02 nd nd 0.11 0.31 Qingdao 0.09 0.01 0.04 0.04 0.26 0.05 0.03 0.03 0.01 nd 0.17 0.73 Total 0.05 0.01 0.02 0.01 0.63 0.03 0.02 0.01 nd 0.02 0.12 0.93

Table S4 Compositions of individual PFASs (%) in soils according to urbanization and river Province Characters PFBA PFPeA PFHxA PFHpA PFOA PFNA PFDA PFUdA PFDoA PFBS PFOS Liaoning Urban 0.0 0.0 0.0 0.0 15.2 60.9 0.0 23.9 0.0 0.0 0.0 Suburban 0.0 0.0 0.0 0.0 34.5 0.0 0.0 65.5 0.0 0.0 0.0 Rural 0.0 0.0 0.0 0.0 16.3 34.9 0.0 30.2 0.0 0.0 18.6 Total 0.0 0.0 0.0 0.0 19.2 38.5 1.9 26.9 0.0 1.9 11.5 Hebei Urban 0.0 0.0 0.0 0.0 0.0 100 0.0 0.0 0.0 0.0 0.0 Suburban 0.0 0.0 0.0 0.0 28.6 64.3 0.0 7.1 0.0 0.0 0.0 Rural 0.0 0.0 0.0 0.0 37.5 37.5 0.0 25.0 0.0 0.0 0.0 Total 0.0 0.0 0.0 0.0 33.3 55.6 0.0 11.1 0.0 0.0 0.0 Tianjin Urban 0.0 0.0 0.0 0.0 9.6 0.0 0.5 4.7 5.5 0.0 79.7 Suburban 0.0 0.0 0.0 0.0 9.1 0.0 2.6 11.8 8.8 0.0 67.7 Rural 0.0 0.0 0.0 3.3 15.8 1.1 13.0 39.1 21.7 0.0 6.0 Total 0.0 0.0 0.0 1.1 11.5 0.3 5.1 17.5 11.5 0.0 53.0 Shandong Urban 9.5 0.0 2.4 0.0 28.6 9.5 2.4 2.4 0.0 9.5 35.7 Suburban 4.2 1.4 4.2 4.2 62.5 4.2 1.4 0.0 0.0 5.6 12.5 Rural 4.5 0.9 1.8 0.9 69.4 4.5 1.8 1.8 0.0 2.7 11.7 Total

5.2 1.0 2.1 1.0 64.9 5.2 2.1 2.1 0.0 3.1 13.4

Liaoning Upstream 0.0 0.0 0.0 0.0 32.7 23.1 0.0 44.2 0.0 0.0 0.0 Midstream 0.0 0.0 0.0 0.0 22.6 12.9 0.0 64.5 0.0 0.0 0.0 Downstream 0.0 0.0 0.0 0.0 2.7 62.2 0.0 18.9 0.0 0.0 16.2 Hebei Upstream 0.0 0.0 0.0 0.0 43.8 18.7 0.0 37.5 0.0 0.0 0.0 Midstream 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Downstream 0.0 0.0 0.0 0.0 0.0 100 0.0 0.0 0.0 0.0 0.0 Tianjin Upstream 0.0 0.0 0.0 0.7 7.1 0.0 6.5 7.2 7.1 0.0 71.4

Midstream 0.0 0.0 0.0 0.0 0.0 0.0 0.0 68.5 31.5 0.0 0.0 Downstream 0.0 0.0 0.0 1.1 6.0 0.0 4.5 24.9 18.1 0.0 45.3 Shandong Upstream 3.9 0.6 1.9 1.3 74.2 3.2 1.3 1.3 1.3 2.6 8.4 Midstream 4.0 2.7 2.7 2.7 56.0 6.7 2.7 1.3 0.0 5.3 16.0 Downstream 8.2 0.0 2.0 2.0 44.9 6.1 4.1 2.0 0.0 6.1 24.5 Table S5 Numbers of soil samples with different land use Woods Grass Grain Cotton Fruit Barren Liaoning 4 4 12 -a - 2 Hebei - 1 3 - - 5 Tianjin 1 - 1 - - 6 Shandong 6 8 11 7 3 5 a: no corresponding soil sample in this land use

Fig. S1 Sampling sites for surface soils in coastal and estuarine areas of the Bohai and Yellow Seas

Fig. S2 Result of normal distribution test for concentrations of ∑PFASs in 79 soils