Characterization of polycyclic aromatic hydrocarbons in concurrently monitored surface seawater and sediment along Dalian coast after oil spill

Ecotoxicology and Environmental Safety 90 (2013) 151–156

Contents lists available at SciVerse ScienceDirect

Ecotoxicology and Environmental Safety journal homepage: www.elsevier.com/locate/ecoenv

Characterization of polycyclic aromatic hydrocarbons in concurrently monitored surface seawater and sediment along Dalian coast after oil spill Xianjie Liu a, Hongliang Jia a, Luo Wang a, Hong Qi b, Wanli Ma b, Wenjun Hong a, Jianguo Guo c, Meng Yang a, Yeqing Sun c, Yi-Fan Li n,a,b,d a

International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), Dalian Maritime University, Dalian, PR China IJRC-PTS, State Key Laboratory of Urban seawater Resource and Environment, Harbin Institute of Technology, Harbin, PR China c Institute of Environmental Systems Biology, Dalian Maritime University, Dalian, PR China d IJRC-PTS, Ryerson University, Toronto, ON, Canada M5B 2K3 b

a r t i c l e i n f o

abstract

Article history: Received 4 September 2012 Received in revised form 21 December 2012 Accepted 22 December 2012 Available online 23 January 2013

Polycyclic aromatic hydrocarbons (PAHs) were measured in concurrently sampled surface seawater and sediment collected at 20 sites around Dalian, China 50 days after an oil spill accident. The concentrations of total PAHs ranged from 15 to 160 ng L  1 in seawater, and from 64 to 2100 ng g  1 dry weight in surface sediment. The spatial trends of PAHs in seawater, but not in sediment, showed a significant negative correlation with the distance from the oil spill site, indicating a strong source of PAHs from oil spill place to the surrounding seawater. The similar profiles for PAH composition in both crude oil and seawater could indicate that oil spill caused PAHs concentration in seawater, but not in sediment. Analysis of water–sediment exchange of PAHs showed that the direction of the net flux of PAHs was from sediment to seawater for most priority PAHs, and from water to sediment for a few HWM-PAHs. & 2012 Elsevier Inc. All rights reserved.

Keywords: Polycyclic aromatic hydrocarbons (PAHs) Oil spill Sea water Sediment China

1. Introduction On July 16, 2010, a fuel pipeline exploded and caught fire in the southwest of Dayao Bay in Dalian, China. About 1500 t of crude oil were spilled from the pipeline. The leakage of crude oil contaminated the surrounding area and the Yellow Sea of China. A large extent of the shoreline in Dalian was significantly polluted. The spilled oil had dramatic negative ecological and economic impacts to the Dalian coastal ecosystem. The physicochemical properties of the oil, with high density and viscosity, as well as a high content of resins and asphaltenes, prompted the formation of stable emulsions with seawater (Franco et al., 2006). Evidences from oil spills have shown that oil can persist in coastal sediments for several decades (Short et al., 2004; Reddy et al., 2002). Polycyclic aromatic hydrocarbons (PAHs), defined as a group of aromatic hydrocarbons with two or more fused benzene rings, are substantially present in crude oil (Ke et al., 2002). The oil spill accident can directly lead to the contamination of PAHs. PAHs have been proved to be the main components responsible for effects on animals, due to their carcinogenic, mutagenic and toxic effects (Lotufo and Fleeger, 1997).

Moreover, PAHs are a class of organic compounds with varying mutagenic properties (Sower and Anderson, 2008). PAHs are mainly from pyrogenic and petrogenic sources (Yunker and Macdonald, 2003). Inputs of PAHs from human activities such as oil spill, offshore production, transportation and combustion are very significant and pose serious threats to coastal habitats (Corredor et al., 1990), so the assessment of the presence and corresponding sources of PAHs after the oil spill was necessary to estimate the impact of accident on the environment. In order to estimate the extent of the impact caused by the oil spill in the coastal area of Dalian city, a concurrent monitoring of PAHs in seawater and surface sediment was carried out from Lingshui Bay to Xiaoyao Bay (see Fig. SI-1, Supplementary Information, (SI)) in September, 2010, 50 days after the accident. The samples of seawater and sediments were analyzed for PAHs to determine the spatial distribution following the accident, to identify the sources, and further more, to determine the flux of PAHs at early spills.

2. Materials and methods

n Correspondence to: author at: Dalian Maritime University, International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), NO. 1, Linghai Road, Dalian, Liaoning 116026, China. Fax: þ 86 411 8472 8489. E-mail addresses: [email protected], [email protected] (Y.-F. Li).

0147-6513/$ - see front matter & 2012 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ecoenv.2012.12.024

2.1. Sampling Surface seawater (0–20 cm) and sediment (0–10 cm) samples taken 50 days after the oil spill were collected along the Dalian coast adjacent to the spill on

152

X. Liu et al. / Ecotoxicology and Environmental Safety 90 (2013) 151–156

September 5, 2010. A map with locations of sampling sites can be found in Fig. SI-1, SI, and detailed information is given in Table SI-1. The twenty sampling sites can be divided into three groups, residential areas (Sites R01–R05), industrial areas (Sites I01–I04), and oil spill areas (Sites OS01–OS11). The sites in the oil spill areas were further divided into two subgroups: OS-1 (OS01–04) containing sites closer to the oil spill site and OS-2 (OS05–11) including sites farther away from the oil spill site. In addition, three crude oil samples were collected near the oil spill site on July 20, 2010. All seawater, sediment and crude oil samples were gathered in a clean acetone rinsed glass bottle with Teflon-lined cap, and sent to the laboratory of the International Joint Research Center for Persistent Toxic Substances (IJRC-PTS), Dalian Maritime University, Dalian, China and stored at  20 1C (sediment and crude oil) and 4 1C (water) until the time for extraction.

2.2. Extraction and analysis Samples were treated, extracted, and analyzed according to the methods established at the National Laboratory for Environmental Testing (NLET), Environment Canada. All solvents used were of pesticide grade purity (J.T. Baker, USA). PAHs standards (24 PAHs compounds) were purchased from the Supelco, Inc. (Supelco, USA), including 5 two-ring PAHs, 7 three-ring PAHs, 4 four-ring PAHs, 6 five-ring PAHs, and 2 six-ring PAHs (See Table 1 for details). After spiking with surrogate standard (Naphthalene-D10, Fluorene-D10, Pyrene-D10, and Perylene-D12) (Ma et al., 2010), 1 L of seawater samples were extracted with 100 mL Dichloromethane (DCM) in a separatory funnel with agitation followed by an hour settling time. Extraction was repeated three times, followed by DCM collection and rotary-evaporation to 1 mL. Ten grams of wet sediment and 10 g anhydrous sodium sulfate were measured into a pre-cleaned extraction thimble and spiked with surrogate standard (Naphthalene-D10, Fluorene-D10, Pyrene-D10, and Perylene-D12). After mixing, samples were Soxhlet extracted for 24 h with 200 mL mixed solvent (hexane/acetone, 1:1 v/v). Extracts were then rotary evaporated to 1 mL. The 1 mL extracts were passed through a 5.5 g silica gel column (Silica 60, Merck, Germany) after a 25 mL hexane pre-rinse and eluted with 40 mL of hexane/DCM mixture (1:1, v/v). The extract was rotaryevaporated to 2 mL, then solvent-exchanged into isooctane and reduced to 1 mL under nitrogen evaporation prior to gas chromatography–mass spectrometry (GC– MS) analysis. For crude oil, 0.2 g of samples were measured into a centrifuge tube and were shaken for 1 h with 5 mL hexane, 2 g anhydrous sodium sulfate were added and then centrifuged for 15 min at a centrifugal force of 1000 g. Take 1 mL extract from top to a vial prior to GC–MS analysis. Further details can be found elsewhere (Wang et al., 2008a). All PAHs were identified and quantified with GC–MS (Finnigan PolarisQ), DB-5 MS of 0.25 mm ID and 30 m length was used. The column oven temperature was

programmed at a rate of 25 1C min  1 from an initial temperature of 60 1C to a temperature of 180 1C (1-min hold), 3 1C min  1 to 280 1C (30-min hold). Injector, transfer line, and ion source temperatures were 280, 250 and 250 1C, respectively. 2.3. Quality assurance/quality control All compounds were identified within7 0.05 min of the calibration standard and selected mass ions. All samples were spiked with a labeled recovery standard (Naphthalene-D10, Fluorene-D10, Pyrene-D10, and Perylene-D12) prior to extraction. The surrogate standard recoveries ranged from 72 to 113 percent (91 7 19 percent) in all samples. Spike and blank samples were included at a rate of one for every ten soils extracted and treated as the same processes with the real samples, the recoveries of all 24 PAHs were 78–110 percent. The instrument detection limits (IDLs) were determined by assessing the injection amount that corresponded to a signal-to-noise value of 3:1, and then transfer this amount in the unit of concentration in the corresponding medium. The IDLs of 24 PAHs ranges from 0.02 to 5.0 ng g  1 dw (dry weight) for sediment samples, and from 0.02 to 4.2 ng L  1 for water samples. Only Nap and Phe were detected in blanks with the mean value of 4.5 and 0.4 ng L  1 in water, 3.7 and 1.5 ng g  1 dw in sediment. The data reported in this study were all blank corrected. 2.4. Organic matter fraction determination Ten grams of sediment samples were isolated for percent moisture determination and total organic mater (uOM) measurement. Sediment samples were first oven-dried at 105 1C for eight hours to a constant weight. After moisture elimination, the samples were placed in a muffle furnace and uOM determined by measuring their loss after baked at 550 1C for five hours. The data of uOM are listed in Table SI-1, SI, ranged from 2.96 to 9.92 percent. Organic carbon fraction (uOC) for each sediment sample can be calculated by assuming uOC ¼ uOM 1.8  1 (Li et al., 2010).

3. Results and discussions 3.1. PAHs in sediment and seawater Detailed PAHs concentrations in seawater and sediment at twenty sites are listed in Table SI-2 and SI-3, SI, respectively, and corresponding data are presented in Table 1. In seawater, the concentration of S24PAHs (total 24 PAH compounds) ranged

Table 1 PAHs concentrations in seawater and sediment in Dalian Bay. PAHs

ThN Nap 2-MN 1-MN BcN Acy Ace Flo Dib Phe Ant Ret Flu Pyr BaA Chr BbF BkF BeP BaP Per DahA IcdP BghiP

Full name

Tetrahydronaphthalene Naphthalene 2-Methy-Naphthalene 1-Methy-Naphthalene Beta-chloronaphthalene Acenaphthylene Acenaphthene Fluorene Dibenzothiopene Phenanthrene Anthracene Retene Fluoranthene Pyrene Benz[a]anthracene Chrysene Benzo[b]fluoranthene Benzo[k]fluoranthene Benzo[e]Pyrene Benzo[a]pyrene Perylene Dibenz[a,h]anthracene Indeno[1,2,3-cd]pyrene Benzo[g,h,i]perylene

Total PAHs a

BDL: below detection limit.

Ring no.

2 2 2 2 2 3 3 3 3 3 3 3 4 4 4 4 5 5 5 5 5 5 6 6

logKOC (L kg  1)

3.11

3.75 3.59 4.15 4.42 4.41 5.22 4.64 5.65 5.45 5.90 6.30 7.20 5.93 6.31 6.50 6.80

Seawater (ng L  1) Mean

Min.

0.26 19 9.9 12 BDL BDL 0.23 3.7 BDL 1.5 4.1 BDL 0.77 1.5 0.15 0.33 0.093 0.054 0.032 0.10 0.11 BDL 0.19 0.18

a

54

Sediment (ng g  1 dw) Max.

Mean

Min.

Max.

BDL 5.4 2.3 3.8 BDL BDL BDL 0.82 BDL 0.43 1.3 BDL 0.22 0.23 BDL BDL BDL BDL BDL BDL BDL BDL BDL BDL

1.1 54 32 30 BDL BDL 1.3 11 BDL 5.1 8.7 BDL 4.4 4.5 0.59 1.4 0.39 0.24 0.24 0.41 0.33 BDL 3.8 3.6

0.11 21 13 9.0 0.063 3.2 4.9 10 2.1 50 14 BDL 52 42 40 23 92 9.0 21 32 11 11 29 22

BDL 5.1 2.7 3.3 BDL 0.60 0.19 3.9 0.62 11 6.0 BDL 7.8 5.9 1.2 3.5 2.0 2.5 1.7 1.7 3.0 BDL 0.65 BDL

0.25 88 37 21 0.15 12 19 28 3.9 190 47 BDL 210 170 220 83 400 23 80 130 33 59 120 112

16

140

510

73

1900

X. Liu et al. / Ecotoxicology and Environmental Safety 90 (2013) 151–156

1200 Concentration (ng/g dw)

Concentration (ng/L)

120 100 80 60 40 20 0

153

IN

Res

OS-1

OS-2

Sites

1000 800 600 400 200 0

IN

Res

OS-1

OS-2

Sites

Fig. 1. Concentrations of S24PAHs from different areas in (a) seawater and (b) sediment. OS-1 (OS01–04): sites in oil spill area closer to the oil spilling site, OS-2 (OS05-11): sites in oil spill area farther away from the oil spill site. Res: residential area (Sites R01-R05), IN: industrial area (Sites I01–I04).

between 16 and 140 ng L  1 with an average of 54 ng L  1, which are much lower than other regions polluted by oil, such as Jiulong River Estuary of China (7000–27,000 ng L  1) and Northern Spanish coast (250–5800 ng L  1), but are comparable with those measured in Mecoa´cfin lake, Mexico (150–760 ng L  1) (Armenta-Arteaga and Elizalde-Gonza´lez, 2003) and Amur Bay, Japan (5–85 ng L  1) (Nemirovskaya, 2007) (see Table SI-4, SI). The highest concentrations were found at site OS03 and OS02 (both were 140 ng L  1) and followed by OS04 (110 ng L  1), all closing to the oil spill site. As shown in Fig. 1(a), PAHs concentrations were significant higher in oil spill area (OS-1) than other areas (Po0.01) in water. This indicates that seawater along Dalian coastal area was greatly affected by oil spill. The concentrations of S24PAHs in sediment ranged between 73 and 1900 ng g  1 dw, with a mean of 510 ng g  1 dw. No significant correlation was found between PAH concentrations and uOM contents in sediment. Compared to other regions polluted by oil, the total PAHs concentrations in sediment from present study is comparable to Hong Kong (590 ng g  1 dw) (Ke et al., 2002), Coastal Tunisia (916–3146 ng g  1 dw) (Zrafi-Nouira et al., 2010), and Amur Bay of Japan (7.2–1100 ng g  1 dw) (Nemirovskaya, 2007) (Table SI-4, SI). Different from the case for seawater, the highest sediment concentrations were observed in the Sites I02 and I03, located in the industrial areas, with a concentration of 1900 ng g  1 dw (Fig SI-2). As shown in Fig. 1(b), PAHs concentrations were significantly higher in industrial area (1200 ng g  1 dw) than residential area (570 ng g  1 dw) (p o0.01) in sediment. Previous studies have already indicated that high PAHs concentration was attributed to the urban and industrial/ harbour areas (Soler et al., 1989; Soriano et al., 2006). The samples collected along the Dayao Bay (Sites OS01 to OS11) showed much lower levels, with an average of 250 ng g  1 dw, indicating that, along the Dayao Bay, the historical input from local sources was smaller in comparison to the industrial and residential areas. Spatial distribution of total PAH levels in sediment samples were significantly different from those in seawater samples (Po0.05), suggesting different sources for PAHs in these two compartments. In order to further assess the distribution and environmental fate of PAHs in the study area, two-dimensional spatial distribution of PAHs in seawater and sediment were analyzed by the software Surfer (Golden Software, Vision 8.0) based on our monitoring data, and the results are given in Fig. 2. The different locations with higher PAHs concentration (dark area) in seawater and sediment suggest the different sources geographically. In seawater (Fig. 2(a)), the sites with higher PAHs concentration were near to the oil spill site (  5 km), and diffused around, which indicated that the oil spill is the main source of PAHs in seawater. The spatial trend of PAHs in sediments,

Fig. 2. The concentrations of S24PAHs in (a) surface seawater (ng L  1) and (b) surface sediment (ng g  1 dw). The black star is where oil spill occurred. The numbers from 121.55 to 122.05 at the bottom are longitude in 1E and the numbers from 38.75 to 39.05 at the left are latitude in 1N.

however, was quite different. Fig. 2(b) shows that, the darkness lays in the industrial area, which tell us that the industrial area was the main source of PAHs. The Pearson correlation between S24PAHs concentration and the distance from the oil spill site were performed both in seawater and in sediment samples. Interestingly, it shows a significant negative relationship (r ¼ 0.61 Po0.01) in seawater (Fig. 3a) rather than sediment. In seawater, the concentrations of PAHs from oil spill site were very high within 5 km and dropped rapidly within 30 km. This finding suggests that the oil spill site was influencing the distribution of PAHs and is also an important source to the PAHs in surface seawater. Pearson correlation analysis was also performed for sediment between S24PAHs concentration and the distance from sampling site I03, and results are presented in Fig. 3b. A significant negative relationship (R¼  0.82, Po0.0001) was found between the PAH concentrations in

154

X. Liu et al. / Ecotoxicology and Environmental Safety 90 (2013) 151–156

2000

160 Concentration (ng/L)

120

Concentration (ng/g dw)

n = 20 r = -0.61 p < 0.001

140 100 80 60 40 20 0

0

5

10

15

20

25

30

35

Distance (km)

n = 20 R = -0.82 p < 0.0001

1600 1200 800 400 0

-5

0

5

10

15

20

25

30

Distance (km)

Fig. 3. Pearson correlation between (a) S24PAHs concentration in surface water and distance from oil spill site, and (b) S24PAHs concentration in sediment and distance from I03.

90 Water Sediment Crude oil

80 Composition (%)

70 60 50 40 30 20

sediment were come from pyrogenic sources, especially coal/ biomass combustion and vehicle exhaust (Chen et al., 2005). PAH profiles in seawater at all sites were compared with that at Site OS-03, and very strong and significant correlations (R ¼0.80–0.99, Po0.0001) were found for all sites, indicating a similar source. Similarly, PAH profiles in sediment were compared with Site I-03, strong and significant correlations (R¼0.75–0.99, Po0.0001) were found for all sites but Site OS-05 (R¼0.28, P¼0.18), which indicated a similar source.

10

3.3. Water–sediment exchange

0 -10

2 ring

3 ring

4 ring

5 ring

6 ring

Rings of PAHs Fig. 4. Rings composition of PAHs in seawater, sediment and crude oil

sediment at each site and its distances from I03 (Fig. 3b), which was not found for seawater. This finding suggests that the industrial area was indeed the major source for the PAHs in sediments.

3.2. Profile of PAHs in crude oil, surface seawater and sediment Composition of PAHs in crude oil, sea surface seawater and sediment based on PAH ring-groups are shown in Fig. 4. In crude oil, low molecular weights (LMW) PAHs (2 3 rings) were the dominant homologs, account for 86 percent of total PAHs, among which Nap (18 percent), 2-MN (23 percent) and 1-MN (18 percent) were dominant PAHs, with a total value of 59 percent, This finding is similar to the results from Wang et al. (2008b). Similar pattern was also found for seawater samples, in which PAHs were dominant by LMW PAHs (2 and 3 rings), accounting for 92 percent. The dominant LMW PAHs in seawater were Nap (34 percent), 2-MN (17 percent) and 1-MN (22 percent), with a total value of 73 percent. High molecular weights (HMW) PAHs (5 and 6 rings, such as BbF, BkF, BghiP, IcdP) accounted for a very small percentage (2.2 percent), and 4-ring PAHs accounted for 5.6 percent. The Similar profiles for PAH homologs in both oil and seawater could indicate that crude oil is the main source in seawater in Dalian coastal area. Very different pattern of PAH composition was found for sediment samples, as shown in Fig. 4. The PAHs in sediment were mostly dominated by HMW PAH homologues (4–6rings), with the percentage of 71 percent. LMW-PAHs (2 and 3) were the minority, which accounted for 29 percent. The dominant PAHs homologs was BbF (16 percent), followed by Phe (11 percent) and Flu (10 percent), which suggests that the concentration of PAHs in

The fugacity fraction (ff) is used to assess equilibrium status of a chemical between two interacting phases, in this case water– sediment exchange can be described as (Please see SI for details)
1 f f ¼ C S C S þ C W jOC K OC ð1Þ where CS is chemical concentration in sediment, in the unit of ng g  1 dw, CW is chemical concentration in water, in the unit of ng mL  1, Organic carbon fraction (uOC) for each sediment sample can be calculated by assuming uOC ¼ uOM 1.8  1. KOC (in mL g  1) is the organic carbon–water partition coefficient (the values of logKOC are given in Table 1 for sixteen priority PAHs). If we define ‘‘in situ organic carbon–water partition coefficient’’ (K0 oc) as:
1 ð2Þ K 0oc ¼ C s C w jOC and Eq. (1) can be rewritten as
1
1 f f ¼ K 0oc K 0oc þ K oc ¼ 1 1 þ K oc K 0oc 1

ð3Þ

when K0 oc is equal to Koc, ff¼0.5, indicating sediment–water equilibrium and no net exchange. When K0 oc is bigger than Koc, ff40.5, which indicates a net flux from sediment to water, while when K0 oc is smaller than Koc, ffo0.5, indicating a net flux from water to sediment. The seawater–sediment equilibrium status was assessed for twenty coupled seawater and sediment data sets, and the values of K0 oc and ff were calculated by using Eqs. (2) and (3). Results presented in Fig. 5 are for sixteen Priority PAHs and four different site categories (industrial and residential areas, and two oil spill areas). A 720 percent of margin of error is assumed when evaluating seawater–sediment equilibrium status based on the treatment due to different sources of uncertainty, such as the use of analytical methods, sampling methods and quality assurance protocols, and parameters used (Harner et al., 2001). As shown in Fig. 5(a), 50 days after the accident, the in situ organic carbon–water partition coefficients (K0 oc) for most of PAH compounds (except HMW-PAHs: DahA, BghiP, and IcdP) in the

X. Liu et al. / Ecotoxicology and Environmental Safety 90 (2013) 151–156

155

8

OS-1

7

OS-2

Log K'OC

6 5

Ind

4

Res

3 2 1 IcdP

BghiP

DahA

BkF

BbF

BaP

Pyr

Flu

Chr

BaA

Phe

Flo

Ant

Acy

Ace

Nap

0

1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0

OS-1 OS-2 Ind

IcdP

BghiP

DahA

BkF

BbF

BaP

Pyr

Flu

Chr

BaA

Phe

Flo

Ant

Acy

Ace

Res

Nap

ff

PAH

PAH Fig. 5. (a) The in situ organic carbon–water partition coefficients (logK0 oc) for the 16 priority PAHs. The blue lines are organic carbon–water partition coefficient (logKoc) for each PAH compound. (b) Fugacity fraction (ff) between water and sediment in Dalian Bay. The dashed lines of ff ¼0.3 and 0.7 are used to represent uncertainties in the equilibrium condition (Harner et al., 2001). OS-1: Oil spill Area-1; OS-2: Oil spill Area-2; Ind: Industrial Area; Res: Residence Area. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

study area are larger than their corresponding organic carbon– water partition coefficients (Koc) represented by the blue lines, and their corresponding ff values are larger than 0.7, indicating that these compounds were saturated in sediment, and net flux of these compounds occurred from sediment to water. Although the higher water concentrations for these PAH compounds caused by the oil spill can lower the values of K0 oc, these levels were not smaller enough to change this direction. DahA was in the equilibrium state in the industrial and residential areas with the values of ff within 0.3 and 0.7, but saturated in water in oil spill areas with ff o0.3, causing the net flux of chemical from water to sediment. The same was true for other two PAH compounds, BghiP and IcdP, both are HWM-PAHs having six rings.

4. Conclusion and implication Concurrent measurement of PAHs in seawater and surface sediment along Dalian coast around the oil spill site 50 days after the accident showed a spatial trend of PAHs centered at the oil spill site in surface seawater and at the industrial site in sediment. This indicated that PAHs in seawater most likely originated from the spill oil and PAHs in sediment were due to historical accumulation of these chemicals mainly originated from industrial activities. Although the oil spill increased the PAH level in seawater, 50 days after the accident, this increase did not significantly change the spatial pattern in sediment, and the direction of the net flux of PAHs between water and sediment, showing from sediment to seawater for most priority PAHs, and from water to sediment for a few HWM-PAHs, such as BghiP and IcdP.

Acknowledgments We are grateful to financial support from Science & Technology Pillar Program of Dalian, China in 2011 (2011E11SF007), and the

Fundamental Research Funds (2012QN054, 2012TD027).

for

the

Central

Universities

Appendix A. Supporting information Supplementary data associated with this article can be found in the online version at http://dx.doi.org/10.1016/j.ecoenv.2012. 12.024.

References Armenta-Arteaga, G., Elizalde-Gonza´lez, M.P., 2003. Contamination by PAHs, PCBs, PCPs and heavy metals in the mecoa´cfin lake estuarine water and sediments after oil spilling. J. Soils Sediments 3, 35–40. Chen, Y., Sheng, G., Bi, X., Feng, Y., Mai, B., Fu, J., 2005. Emission factors for carbonaceous particles and polycyclic aromatic hydrocarbons from residential coal combustion in China. Environ. Sci. Technol. 39, 1861–1867. Corredor, J.E., Morell, J.M., Del Castillo, C.E., 1990. Persistence of spilled crude oil in a tropical intertidal environment. Mar. Pollut. Bull. 21, 385–388. ˜ as, L., Soriano, J., De Armas, D., Gonza´lez, J., Beiras, R., Salas, N., Franco, M., Vin Bayona, J., Albaige´s, J., 2006. Spatial distribution and ecotoxicity of petroleum hydrocarbons in sediments from the Galicia continental shelf (NW Spain) after the Prestige oil spill. Mar. Pollut. Bull. 53, 260–271. Harner, T., Bidleman, T.F., Jantunen, L.M.M., Mackay, D., 2001. Soil–air exchange model of persistent pesticides in the United States cotton belt. Environ. Toxicol. Chem. 20, 1612–1621. Ke, L., Wong, T.W.Y., Wong, Y.S., Tam, N.F.Y., 2002. Fate of polycyclic aromatic hydrocarbon (PAH) contamination in a mangrove swamp in Hong Kong following an oil spill. Mar. Pollut. Bull. 45, 339–347. Li, Y.F., Harner, T., Liu, L., Zhang, Z., Ren, N., Jia, H., Ma, J., Sverko, E., 2010. Polychlorinated biphenyls in global air and surface soil: distributions, air–soil exchange, and fractionation effect. Environ. Sci. Technol. 44, 2784–2790. Lotufo, G.R, Fleeger, J.W, 1997. Effects of sediment-associated phenanthrene on survival, development and reproduction of two species of meiobenthic copepods. Mar. Ecol. Prog. Ser. 151, 91–102. Ma, W.L., Li, Y.F., Qi, H., Sun, D., Liu, L., Wang, D., 2010. Seasonal variations of sources of polycyclic aromatic hydrocarbons (PAHs) to a northeastern urban city, China. Chemosphere 79, 441–447. Nemirovskaya, I.A, 2007. Hydrocarbons in the water and bottom sediments of a region with continuous petroleum contamination. Geochem. Int. 45, 638–651.

156

X. Liu et al. / Ecotoxicology and Environmental Safety 90 (2013) 151–156

Reddy, C.M., Eglinton, T.I., Hounshell, A., White, H.K., Xu, L., Gaines, R.B., Frysinger, G.S., 2002. The West Falmouth oil spill after thirty years: the persistence of petroleum hydrocarbons in marsh sediments. Environ. Sci. Technol. 36, 4754–4760. Short, J.W., Lindeberg, M.R., Harris, P.M., Maselko, J.M., Pella, J.J., Rice, S.D., 2004. Estimate of oil persisting on the beaches of Prince William Sound 12 years after the Exxon Valdez oil spill. Environ. Sci. Technol. 38, 19–25. ˜ o, M., 1989. Distribution of Soler, M., Grimalt, J.O, Albaiges, J., Mendez, J., Marin aliphatic, aromatic and chlorinated hydrocarbons in mussels from the Spanish Atlantic coast (Galicia). An assessment of pollution parameters. Chemosphere 19, 1489–1498. ˜ as, L., Franco, M.A, Gonza´lez, J.J, Ortiz, L., Bayona, J.M, Albaige´s, J., Soriano, J.A, Vin 2006. Spatial and temporal trends of petroleum hydrocarbons in wild mussels from the Galician coast (NW Spain) affected by the Prestig oil spill. Sci. Total Environ. 370, 80–90. Sower, G.J., Anderson, K.A., 2008. Spatial and temporal variation of freely dissolved polycyclic aromatic hydrocarbons in an urban river undergoing superfund remediation. Environ. Sci. Technol. 42, 9065–9071.

Wang, D., Yang, M., Jia, H., Li, Y., 2008a. Chemical fingerprinting of polycyclic aromatic hydrocarbons in crude oil and petroleum product samples. Environ. Pollut. Control 30, 62–65, in Chinese. Wang, D., Yang, M., Jia, H., Zhou, L., Li, Y., 2008b. Seasonal variation of polycyclic aromatic hydrocarbons in soil and air of Dalian areas, China: an assessment of soil–air exchange. J. Environ. Monit. 10, 1076–1083. Yunker, M.B., Macdonald, R.W., 2003. Alkane and PAH depositional history, sources and fluxes in sediments from the Fraser River Basin and Strait of Georgia, Canada. Org. Geochem. 34, 1429–1454. Zrafi-Nouira, I., Safi, N.M.D., Bahri, R., Mzoughi, N., Aissi, A., Abdennebi, H.B., Saidane-Mosbahi, D., 2010. Distribution and sources of polycyclic aromatic hydrocarbons around a petroleum refinery rejection area in Jarzouna–Bizerte (Coastal Tunisia). Soil Sediment Contam. 19, 292–306.