Marine Pollution Bulletin 80 (2014) 52–58
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Distribution, sources and ecological risk assessment of PAHs in surface sediments from Guan River Estuary, China Xinran He a,b,⇑, Yong Pang a, Xiaojuan Song b, Binlin Chen c, Zhihua Feng d, Yuqin Ma b a
College of Environment, Hohai University, Nanjing 210098, China Lianyungang Environmental Monitoring Central Station, Lianyungang 222001, China c Lianyungang Environmental Protection Bureau, Lianyungang 222001, China d College of Marine Science & Technology, Huaihai Institute of Technology, Lianyungang 222005, China b
a r t i c l e
i n f o
Keywords: PAHs Surface sediment Ecological risk Sediment quality guidelines Molecular ratios Guan River Estuary
a b s t r a c t The contamination of surface sediments in Guan River Estuary, China, by polycyclic aromatic hydrocarbons (PAHs) has been fully investigated. Total concentrations of 21 PAHs ranged from 90 to 218 ng/g with an average of 132.7 ng/g, which is relatively low in comparison with other estuaries around the world. PAH concentrations appeared to be positively correlated with clay content and negatively correlated with sediment grain size. Source identification implied that the PAHs originated mainly from pyrolytic sources. However, source patterns may be continuously changed to a petrogenic origin due to the heavy ship traffic and continuous discharge of oily sewage in this area. The PAH levels were also compared with international Sediments Quality Guidelines and Sediments Quality Criteria, and the results indicated low negative effects for most individual PAHs. However, toxic effects related to FLO would occur occasionally in most locations in the estuary. Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction Polycyclic aromatic hydrocarbons (PAHs), a typical group of chemicals containing two or more aromatic rings, are prevalent in the environment. Because of their persistence, carcinogenicity, toxicity and mutagenicity (Zedeck, 1980; Marin-Morales et al., 2009), PAHs are of particular concern, and 16 priority PAHs are regulated by the United States Environmental Protection Agency (USEPA). For decades, the distribution and sources of PAHs have been the focus of numerous investigations (Soclo et al., 2000; Doong and Lin, 2004; Men et al., 2009; Chen and Chen, 2011; Barakat et al., 2011; Huang et al., 2012). PAHs can derive from natural sources, but anthropogenic activity is generally considered to be the major source (Baumard et al., 1998). Pyrogenic and petrogenic sources are two major origins of anthropogenic PAHs in the environment. Pyrogenic PAHs are formed as trace contaminants by the incomplete combustion of organic matter, such as wood, fossil fuels, asphalt and industrial waste. Petrogenic PAHs are usually contained in crude and refined petroleum (Liu et al., 2009). Once produced, PAHs can be transported to the marine environment through wastewater discharge, surface runoff, atmospheric ⇑ Corresponding author at: Lianyungang Environmental Monitoring Central Station, Lianyungang 222001, China. Tel.: +86 518 8552 1756. E-mail address: [email protected] (X. He). http://dx.doi.org/10.1016/j.marpolbul.2014.01.051 0025-326X/Ó 2014 Elsevier Ltd. All rights reserved.
deposition and other means, such as oil leaks (Heemken et al., 2000). In the marine environment, PAHs adhere tightly to sediments because of their high hydrophobicity and weak degradation (Warren et al., 2003). When the environmental conditions change, the adsorbed PAHs can be resuspended into the water via chemical and biological processes, which thus cause secondary pollution to the surroundings (Wang et al., 2010; Lu et al., 2012). Therefore, sediments act both as an important reservoir and as a secondary source for PAH contamination, and the investigation of sedimentary PAHs is needed to provide estimates of PAH inputs into marine areas. Guan River is the only natural river in northern Jiangsu Province with no water-gates on the main stream, which connects to the Beijing–Hangzhou Grand Canal and the Yangtze River in China (Liu et al., 2006). It flows into the Yellow Sea at the estuary, which facilitates trade with Japan and Korea. In terms of economic development, Guan River plays an important role in Jiangsu, equal to that of the Rhine in Germany and the Thames in England. In recent years, Guan River Estuary (GRE) has experienced a great deal of economic development, leading to an increasing risk of pollution by toxic chemicals. Previous studies have shown that with the increases of local sources, heavy metal pollution of surface sediments has become more and more serious in this area (Yuan and Liu, 2003; Huang and Yin, 2007; Chen et al., 2008). In the case of PAHs, both local sources and long-range atmospheric transport may play
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X. He et al. / Marine Pollution Bulletin 80 (2014) 52–58
important roles in their distributions (Lammel et al., 2007; Tamamura et al., 2007). However, there is a scarcity of data on sedimentary PAHs, and this gap must be filled so that an effective environmental policy can be built upon sound scientific knowledge of the emission sources. The present work aimed to determine the levels and spatial distribution of PAHs in surface sediments in GRE and to identify the major sources of PAHs in this area. Special attention has also been paid to ecological risk assessment of PAHs because of their threats to human health. 2. Materials and methods 2.1. Sample collection Thirteen surface sediment samples were collected using a stainless steel grab sampler in April 2011. The sample locations are shown in Fig. 1. All samples were placed in dark glass bottles that had been pre-washed with n-hexane and kept in a refrigerator at 20 °C for further analysis.
Table 1 PAHs analyzed in this study. PAHs compounds
Abbreviation
Naphthalene Acenaphthylene Acenaphthene Fluorene Anthracene Phenanthrene Benzo(a)anthracene Chrysene Fluoranthene Pyrene Benzo(a)pyrene Dibenzo(a,h)anthracene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(g,h,i)perylene Indeno(1,2,3-cd)pyrene Benzo(c)phenanthrene Benzo(e)pyrene Benzo(j)fluoranthene 7,12-Dimethylbenz(a)anthracene 3-Methylcholanthrene
NAP ACY ACE FLO ANT PHE BaA CHR FLA PYR BaP DBahA BbF BkF BghiP IcdP BcP BeP BjF 7,12-DMBA 3-MECA
2.2. Chemicals A composite standard solution of 21 PAHs (Table 1) at 2000 mg/ L was obtained from AccuStandard Chem. Co. (USA). Deuterated PAH internal standard solutions (ACE-d10, PHE-d10, CHR-d12 and perylene-d12) at 4000 mg/L and surrogate standard solutions (2fluorobiphenyl and 4-terphenyl-d14) at 2000 mg/L were also purchased from AccuStandard. A certified reference material (CRM) sample was obtained from National Institute of Standards and Technology (NIST, SRM 1941). All solvents used for sample processing and analysis were HPLC grade from Tedia Co. (USA). Deionized water was produced by a Milli-Q system (Millipore Co., USA). Analytical grade anhydrous sodium sulfate was also used. 2.3. Sample preparation and analysis For PAH analysis, sediments were freeze-dried, crushed into fine powders, and passed through an 80-mesh sieve. Sieved samples of 10 g each were mixed with anhydrous sodium sulfate and Soxhlet-extracted with 80 ml hexane/acetone (1:1 v/v) for 24 h. Prior to analysis, internal standard solutions were added to each
extract, which was then cleaned-up by Gel Permeation Chromatography (LC-Tech, ultra 10836). GPC was carried out with a column of 500 mm 25 mm i.d. filled with 20 g of biobeads. As the mobile phase, chloroform was used at a flow rate of 5 mL min 1. The extract was rinsed out under 180 mbar and collected between 1600 and 2200 s. The extract volume was further reduced to 1.0 ml using a purified nitrogen stream and sealed in an amber vial for analysis. The concentrated extract was analyzed by gas chromatographymass spectrometry (GC–MS) using an Agilent 7890 GC and an Agilent 5975C MS with a DB-5MS capillary column (30 m 0.25 mm i.d., 0.25-lm film thickness). An aliquot of 1.0 lL sample extract was injected into the GC–MS with split stream sampling (split ratio: 10:1). The oven programme maintained the temperature at 50 °C for 1 min, then increased it from 50 to 180 °C at 4 °C/min and from 180 to 280 °C at 15 °C/min, and finally held it constant for 5 min. Helium was used as the carrier gas at a flow rate of 1.0 mL/min. The injector temperature was maintained at 250 °C. An electron impact ion source (EI) with electron energy of 70 eV was used for the MS, and the mass range scanned was from 50
Fig. 1. Map of sampling sites in GRE.
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X. He et al. / Marine Pollution Bulletin 80 (2014) 52–58
to 500 amu under selected ion monitoring mode. The ion source, quadrupole and transfer line temperatures were held at 230, 150 and 280 °C, respectively. Identification of individual PAHs was based on the selected ions and the comparison of retention time between samples and the standard solution. In addition, the granularity of the sediment was analyzed using a Laser Particle Size Analyzer (Malvern 2000, England). Prior to analysis, organic materials were removed from sediment by treatment with hydrogen peroxide. 2.4. Quality assurance and quality control Analysis of the set of samples was accompanied by procedural blanks (solvent), spiked blanks (standards spiked into solvent), sample duplicates, and a CRM sample, all of which were carried through the entire analytical procedure in a manner identical to that used for the samples. Procedural blanks showed no detectable amounts of PAHs. Recoveries in matrix spikes were 75–120%. Relative percent difference (RPD) of duplicate samples was less than 25%. Recoveries in the CRM sample were between 77% and 105% of the certified values. One tenth of the samples were spiked with surrogates prior to extraction, with mean recoveries ranging from 75% to 83%. PAHs were quantified using the internal calibration method based on five-point calibration curves for individual compounds. The response factors based on calibration curves showed acceptable relative standard deviation (RSD) values (lower than 20%). The detection limits were estimated from a signal-to-noise ratio of 3:1 in blank samples (n = 7) and ranged from 0.1 to 0.9 ng/g for individual PAH compounds. All results were expressed on a dry weight basis. Glassware was washed with n-hexane and dried in an oven at 105 °C prior to use. Other materials were prewashed with ultrapure water and acetone. 3. Results and discussion 3.1. Level and spatial distribution of PAHs The concentrations of PAHs in surface sediments of GRE are summarized in Table 2, and the spatial distribution patterns are depicted
in Fig. 2. TPAHs, defined as the total concentration of 21 PAHs, ranged from 90 to 218 ng/g with a mean value of 132.7 ng/g. The total concentration of 16 priority PAHs ranged from 43 to 169 ng/g with a mean value of 104.2 ng/g. 9 PAHs (ACY, ACE, FLO, PHE, ANT, FLA, PYR, BbF and BkF) were detected at all of the stations, and the remaining 12 PAHs were detected at most of the stations. The average detection frequency of individual PAH compounds in surface sediments at 13 monitoring sites was up to 99.3%. As shown in Fig. 2, the spatial distribution of TPAHs was very similar to that of 16 PAHs. The higher concentrations were observed at stations near the entrance of GRE (H07 and H05), whilst the lower concentrations were generally found outside the entrance or beyond the nearshore region (H02, H03 and H08), suggesting that the amounts of PAHs were related to urban runoff and sewage discharges. In addition, tidal current might also influence the distribution of PAHs. Lower concentrations of PAHs at H10 or H11 might be due to higher tidal currents with less sediment deposition than H07 (Zhang and Zhang, 1993). Previous studies have shown that concentrations of PAHs in sediments are influenced by a number of factors including total organic carbon (TOC) content, mean sediment grain size, clay content, currents and so on (Yang, 1999; Luo et al., 2004). Generally, smaller particles exhibit a higher surface-to-volume ratio than larger ones and consequently have higher organic carbon content. Thus, the content of the adsorbed contaminants is often higher (Chiou et al., 1998). As shown in Fig. 3, TPAHs in sediments in GRE were positively correlated with clay content and negatively correlated with mean sediment grain size (samples collected at H01 to H07 were calculated for showing the correlations). Huang et al. (2012) also found significant positive correlations between total PAHs and TOC or silt–clay content in Zhanjiang Bay and Leizhou Bay in China. Therefore, particle size and clay content both play an important role in the distribution of PAHs in surface sediments of GRE. A comparison of PAH concentrations in surface sediments collected from different estuaries and bays in China and abroad is given in Table 3. The levels of sediment contamination by PAHs can be classified into four categories: (a) low, 0–100 ng/g; (b) moderate, 100–1000 ng/g; (c) high, 1000–5000 ng/g and (d) very high,
Table 2 Measured concentrations (ng/g) of PAHs in surface sediments from GRE. H01 NAP ACY ACE FLO PHE ANT FLA PYR BaA CHR BcP 7,12-DMBA BbF BkF BaP DBahA BeP BjF 3-MECA IcdP BghiP 2–3-ring PAHs 4–6-ring PAHs 16 PAHs TPAHs a b
1.0 12.0 2.0 26.0 3.0 3.0 3.0 1.0 1.0 1.0 ND ND 36.0 20.0 ND 1.0 ND ND ND 17.0 2.0 47.0 82.0 129 129
H02
H03
H04
H05
H06
H07
H08
H09
H10
H11
H12
H13
MDLa
1.0 6.0 11.0 34.0 1.0 1.0 2.0 1.0 ND 1.0 2.0 2.0 1.0 1.0 ND 1.0 13.0 ND 5.0 13.0 1.0 54.0 43.0 75.0 97.0
b
1.0 4.0 9.0 1.0 1.0 3.0 2.0 1.0 1.0 ND 2.0 1.0 12.0 1.0 1.0 1.0 43.0 2.0 8.0 2.0 3.0 19.0 80.0 43.0 99.0
17.0 12.0 6.0 25.0 3.0 2.0 2.0 2.0 1.0 2.0 1.0 2.0 38.0 8.0 3.0 16.0 15.0 3.0 6.0 ND ND 65.0 99.0 137 164
5.0 7.0 8.0 22.0 1.0 3.0 2.0 1.0 1.0 1.0 1.0 1.0 30.0 26.0 1.0 2.0 20.0 1.0 6.0 ND ND 46.0 93.0 110 139
27.0 4.0 8.0 31.0 1.0 4.0 2.0 2.0 1.0 1.0 ND 2.0 31.0 20.0 1.0 25.0 35.0 1.0 11.0 11.0 ND 75.0 143 169 218
5.0 8.0 3.0 3.0 2.0 1.0 3.0 1.0 ND 1.0 1.0 ND 19.0 2.0 1.0 2.0 20.0 1.0 13.0 3.0 1.0 22.0 68.0 55.0 90.0
7.0 14.0 5.0 26.0 2.0 1.0 2.0 1.0 2.0 1.0 2.0 2.0 30.0 7.0 2.0 3.0 20.0 3.0 3.0 1.0 1.0 55.0 80.0 105 135
14.0 12.0 8.0 22.0 2.0 3.0 3.0 1.0 1.0 1.0 1.0 1.0 26.0 9.0 2.0 15.0 21.0 3.0 4.0 1.0 ND 61.0 89.0 120 150
18.0 8.0 10.0 32.0 4.0 2.0 2.0 1.0 1.0 1.0 2.0 1.0 32.0 21.0 1.0 8.0 12.0 2.0 3.0 2.0 ND 74.0 89.0 143 163
14.0 5.0 7.0 19.0 1.0 2.0 2.0 1.0 1.0 1.0 ND 1.0 18.0 14.0 3.0 7.0 21.0 2.0 2.0 3.0 1.0 48.0 77.0 99.0 125
3.0 9.0 6.0 22.0 1.0 3.0 2.0 2.0 2.0 2.0 1.0 1.0 23.0 9.0 2.0 13.0 17.0 2.0 2.0 4.0 1.0 44.0 83.0 104 127
0.2 0.5 0.6 0.3 0.9 0.9 0.8 0.7 0.2 0.2 0.5 0.8 0.3 0.4 0.4 0.2 0.3 0.5 0.1 0.2 0.1
MDL: method detection limit. ND: not detected and indicates 0 ng/g.
ND 4.0 8.0 33.0 1.0 1.0 1.0 5.0 2.0 2.0 1.0 1.0 1.0 2.0 1.0 ND 18.0 1.0 3.0 4.0 1.0 47.0 43.0 66.0 90.0
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PAHs did not vary much from one sampling site to another, indicating similar PAH sources over the whole area. At most of the stations, the 5-ring PAHs were the most abundant, accounting for an average of 50.8% of the total PAHs. The 3-ring PAHs followed, with an average of 32.4%. Both the higher molecular compounds (5-ring PAHs) and lower molecular compounds were representative of the total PAH compounds in GRE. 3.3. Source apportionment of PAHs
Fig. 2. Distribution of TPAHs and 16 PAHs.
>5000 ng/g (Baumard et al., 1998). The PAH pollution level in GRE was low to moderate. The mean concentration of 16 PAHs was only slightly higher than that of Leizhou Bay, and it was lower than in most other bays shown in Table 3. The comparisons suggest that current contamination levels of PAHs in GRE are relatively low compared to other estuaries in China and around the world. 3.2. Composition of PAHs The composition patterns of PAHs by ring size in surface sediments of GRE are shown in Fig. 4. The percentage composition of
Recognition of PAH sources is necessary for control of their input and for allocating responsibility for remedial activities. A number of studies have demonstrated the practicability of using PAH isomeric ratios in source apportionment (Sicre et al., 1987; Budzinski et al., 1997; Soclo et al., 2000; Magi et al., 2002). In the present study, the ratios of low molecular weight PAHs (LMW) to high molecular weight PAHs (HMW), PHE/ANT and FLA/PYR were used to identify the PAH sources. The majority of PAHs in marine sediments originate from pyrogenic or petrogenic sources. Pyrolytic PAHs are produced during incomplete combustion of carbon, wood and fossil fuels, and they are characterized by compounds with four or more aromatic rings. In contrast, petrogenic PAHs contain only two or three aromatic rings (Soclo et al., 2000; Wang et al., 2006). Therefore, the ratio of LMW to HMW has been used to distinguish pyrogenic (1) sources. Table 4 shows the ratios of LMW/
Fig. 3. Correlation plots of TPAHs vs. clay content and mean sediment grain size.
Table 3 A comparison of PAH concentrations (ng/g) in surface sediments from different locations around the world.
a
Location
na
Range
Mean
References
Leizhou Bay, China GRE, China Yellow River Estuary, China Bohai Bay, China Liaodong Peninsula, China Yangtze Estuary, China Jinzhou Bay, China Zhanjiang Bay, China Quanzhou Bay, China Rizhao Coastal, China Xiamen Bay, China Daliao Estuary, China Liaohe Estuary, China Dalian Bay, China Narragansett Bay, USA Izmit Bay, Marmara Sea Ulsan bay, Korea Aegean sea, Greek Adriatic Sea, Italy Mediterranean, Egypt Saco do Laranjal, Brazil Lenga Estuary, Chile
16 16 16 16 16 16 16 16 16 16 16 16 16 16 44 16
21.72–319.61 43–169 111.3–204.8 54.6–202.3 144.5–205.3 90.14–502.12 133.44–593.91 41.96–933.90 182.8–721.1 79.3–853 203.98–1590.47 276.26–1606.89 704.7–1804.5 157–20855 569–2.16 105 3.0 104–1.67 106 17–3100 45–148 24.1–501.1 3.51–14100 7.3–93.2 290–6118
103.91 104.2 115.8 140.0 173.0 221.18 262.15 315.98 353.8 360 670 743.03 1001.9 7642 21100 6.01 105 – – – 786
Huang et al. (2012) This study Hu et al. (2011) Huang et al. (2011) Hu et al. (2010) Li et al. (2012) Xu et al. (2011) Huang et al. (2012) Zhuang et al. (2011) Chen et al. (2012) Li et al. (2009) Men et al. (2009) Lang et al. (2011) Liu et al. (2011) Hartmann et al. (2004) Telli-Karakoc et al. (2002) Khim et al. (2001) Papadopoulou and Samara (2002) Magi et al. (2002) Barakat et al. (2011) Filho et al. (2012) Pozo et al. (2011)
16 16 16
n: Number of PAH compounds analyzed in each study.
2025
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X. He et al. / Marine Pollution Bulletin 80 (2014) 52–58
100% 80% 60% 40% 20% 0% H01 2-ring PAHs
H02 H03 H04
H05 H06 H07 H08
3-ring PAHs
4-ring PAHs
H09 H10 H11 5-ring PAHs
H12 H13 6-ring PAHs
Fig. 4. The composition pattern of PAHs by ring size in surface sediments from GRE.
HMW, which were 1, indicating that petrogenic sources could occasionally contribute to PAH contamination in this area. The PHE/ANT ratio can also provide useful information for distinguishing PAHs of various origins (Budzinski et al., 1997; Yunker et al., 2002). PHE and ANT are two structural isomers, with PHE being the more thermodynamically stable. Therefore, a higher PHE/ANT ratio is observed in petrogenic pollution, and a lower ratio in pyrolytic pollution. Sediments with PHE/ANT > 10 indicate petrogenic contamination, while PHE/ANT < 10 are typical of pyrolytic sources. In the present study, the PHE/ANT ratios were in the range 0.25–2.00 (Table 4), clearly indicating a pyrolytic source. Similar results were observed for the FLA/PYR ratios. It is assumed that petroleum often contains more thermodynamically stable compounds such as NAP, FLO, PHE and CHR, while FLA and PYR are usually the most abundant compounds in pyrolytic PAHs (Sicre et al., 1987; Magi et al., 2002; Zhang et al., 2004). Therefore, FLA/PYR ratios greater than 1 indicate pyrolytic origin, while values less than 1 are attributed to petrogenic sources (Magi et al., 2002). As shown in Table 4, the ratio of FLA/PYR was larger than 1 at 9 sites, suggesting predominantly pyrolytic sources. The ratio was lower than 1 at site H02, indicating that petrogenic sources might also contribute to PAH contamination in this area. In conclusion, the three ratios present consistent results. Pyrogenic PAHs were dominant in the sediments in this area. GRE is a popular site for tourists, and ship traffic may contribute to PAH input in this area. Pyrolytic PAHs may come from the exhaust of diesel engines. In addition, heavy traffic and coal heating could also result in the increase of PAH loadings through atmospheric deposition and freshwater runoff. In some parts of the area, petrogenic PAHs may contribute to PAH contaminations, which could come from oil/gas/diesel spills and oily sewage discharges from ambient estuary.
freshwater and marine environments (MacDonald et al., 2000; Long et al., 2006). BEDS contains various types of data that can be used to establish links between the concentration of a given chemical and its biological effect. These data come from field studies, spiked-sediment toxicity tests and equilibrium partitioning models. SQGs provide two target values: effects range low (ERL) and effects range median (ERM), which are established using the 10th and 50th percentiles, respectively, in a database of increasing concentrations associated with adverse biological effects. PAH concentrations lower than ERL are considered not to be harmful to organisms, while concentrations higher than ERM are considered to be harmful frequently. PAHs with concentrations between ERL and ERM are considered to be harmful occasionally (Long et al., 1995, 1998; MacDonald et al., 1996). Table 5 presents the toxicity guidelines for 12 individual PAHs and identifies the stations in the three different ranges defined by ERL and ERM. Concentrations of individual PAHs at stations H04 and H08 were all below the ERL, suggesting that biological effects at these two stations would rarely occur. However, in the case of the other 11 stations, concentrations of FLO were between the ERL and ERM, which indicates that biological effects related to FLO would occur occasionally at these stations.
3.4.2. Sediment quality criteria (SQC) SQC are based on SQGs combined with consideration of natural, economic, social, technical and other conditions. We have not established any related standards for PAHs in China. In the present study, we assessed PAH contamination levels in surface sediments of GRE according to the SQC used in Canada (ECM, 2007). This standard contains five effect levels: the rare effect level (REL), the threshold effect level (TEL), the occasional effect level (OEL), the probable effect level (PEL) and the frequent effect level (FEL). These five values for 12 PAHs are presented in Table 6, which could be applied in developing strategies for environmental management (including restoration, dredging, pollution control). Biological risks of 12 PAH compounds in surface sediments of GRE were also evaluated according to the sediment quality standard applied in Canada (ECM, 2007). Table 7 shows the sampling sites at which concentrations of at least one PAH were greater than the lowest level. The results show that PAH concentrations at all 13 sampling sites of GRE were between TEL and OEL, indicating that adverse effects of PAHs in this area are unlikely. For the time being, further assessment of the environmental risks associated with PAHs in this area is not necessary, and there are no surface sediments in need of remediation. However, long-term monitoring should be undertaken in order to detect new contamination, and investigation of the origin and environmental impacts of PAHs should be carried out in depth.
4. Conclusions 3.4. Risk assessments of PAHs in surface sediments 3.4.1. Sediment quality guidelines (SQGs) SQGs developed on the basis of Biological Effects Database for Sediments (BEDS) are very useful for sediment assessments in
PAH concentrations in surface sediments of GRE are relatively low at the present time in comparison with other estuaries worldwide. The spatial distributions were determined by considering different properties of the sediments, and it was found that con-
Table 4 Characteristic values of LMW/HMW, PHE/ANT and FLA/PYR at different sampling sites in GRE. Sampling sites
LMW/HMWa PHE/ANT FLA/PYR a
H01
H02
H03
H04
H05
H06
H07
H8
H9
H10
H11
H12
H13
0.57 1.00 3.00
1.26 1.00 2.00
1.09 1.00 0.20
0.24 0.33 2.00
0.66 1.50 1.00
0.49 0.33 2.00
0.52 0.25 1.00
0.32 2.00 3.00
0.69 2.00 2.00
0.69 0.67 3.00
0.83 2.00 2.00
0.62 0.50 2.00
0.53 0.33 1.00
LMW/HMW: concentration ratio of 2–3-ring PAHs to 4–6-ring PAHs.
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X. He et al. / Marine Pollution Bulletin 80 (2014) 52–58 Table 5 Concentration ranges of PAHs in sediments from GRE and toxicity guidelines. Compound
ACE ACY ANT FLO NAP PHE LMW PAHs BaA BaP CHR DBahA FLA PYR HMW PAHs Total PAHs a
SQGa (ng/g)
Concentration range (ng/g)
ERL
ERM
16 44 85.3 19 160 240 552 261 430 384 63.4 600 665 1 700 4 022
500 640 1 100 540 2 100 1 500 3 160 1 600 1 600 2 800 260 5 100 2 600 9 600 44 792
Sites
2.0–11.0 4.0–14.0 1.0–4.0 1.0–34.0 ND-27.0 1.0–4.0 19–75 ND-2.0 ND-3.0 ND-2.0 ND-25.0 1.0–3.0 1.0–5.0 43–143 90–218
ERM
All sites All sites All sites H04 and H08 All sites All sites All sites All sites All sites All sites All sites All sites All sites All sites All sites
– – – H01, H02, H03, H05, H06, H07, H09, H10, H11, H12 and H13 – – – – – – – – – – –
– – – – – – – – – – – – – – –
SQG values taken from Long et al. (1995) and MacDonald et al. (1996).
Table 6 Criteria for the assessment of marine sediment quality relative to PAHs in Canada (ng/ g). PAHs
REL
TEL
OEL
PEL
FEL
ACE ACY ANT BaA BaP CHR DBahA FLA FLO NAP PHE PYR
3.7 3.3 16 27 34 37 3.3 27 10 17 23 41
6.7 5.9 47 75 89 110 6.2 110 21 35 87 150
21 31 110 280 230 300 43 500 61 120 250 420
89 130 240 690 760 850 140 1500 140 390 540 1400
940 340 1100 1900 1700 2200 200 4200 1200 1200 2100 3800
Table 7 Risk assessments of PAHs according to the sediment quality criteria. Range of sediment quality critera
Sampling sites
Higher than FEL Between PEL and FEL Between OEL and PEL Between TEL and OEL Between REL and TEL Lower than REL
– – – All sites – –
centrations of TPAHs were positively correlated with clay content and negatively correlated with mean sediment grain size. Based on selected PAH ratios, it was concluded that the pyrogenic PAHs were dominant in the sediments and were probably due to vessel and vehicle exhaust from diesel engines, as well as coal combustion from domestic heating systems. In some parts of the area, petroleum sources from fuel spills and oily sewage discharges might also contribute to PAH pollution. It is important to emphasize that the source patterns of PAHs may change continuously because of the intense traffic in this area. The ecotoxicological risk evaluation based on international SQGs and SQC indicated that the probability of negative effects caused by 11 PAH compounds is low. However, toxic effects related to FLO would occur occasionally in most locations in the estuary. Results obtained in the present study have provided useful information to evaluate PAH contamination levels in surface sediments of GRE, which is an economically important region in China due to industry and tourism.
Acknowledgements This work was supported by the National Natural Science Foundation of China (51179053), the Science and Technology Development Project in Lianyungang City (SH1113) and the Environmental Technology Project in Jiangsu Province (2010043).
References Barakat, A.O., Mostafa, A., Wade, T.L., Sweet, S.T., ElSayed, N.B., 2011. Distribution and characteristics of PAHs in sediments from the Mediterranean coastal environment of Egypt. Mar. Pollut. Bull. 62, 1969–1978. Baumard, P., Budzinski, H., Garrigues, P., 1998. Polycyclic aromatic hydrocarbons in sediments and mussels of the Western Mediterranean Sea. Environ. Chem. 7, 765–776. Budzinski, H., Jones, I., Bellocq, J., Pierrad, C., Garrigues, P., 1997. Evaluation of sediment contamination by polycyclic aromatic hydrocarbons in the Gironde estuary. Mar. Chem. 58, 85–97. Chen, B.L., He, X.R., Wang, T.Y., Liu, H., 2008. Heavy metals pollution and potential ecological risk in sediment of Lianyungang sea area. Mar. Environ. Sci. 27, 246– 249 (in Chinese). Chen, C.W., Chen, C.F., 2011. Distribution, origin, and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in sediments of Kaohsiung Harbor. Taiwan. Mar. Pollut. Bull. 63, 417–423. Chen, H.Y., Teng, Y.G., Wang, J.S., 2012. Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Rizhao coastal area (China) using diagnostic ratios and factor analysis with nonnegative constraints. Sci. Total Environ. 414, 293–300. Chiou, C.T., McGroddy, S.E., Kile, D.E., 1998. Partition characteristics of polycyclic aromatic hydrocarbons on soilsand sediments. Environ. Sci. Technol. 32, 264– 269. Doong, R.A., Lin, Y.T., 2004. Characterization and distribution of polycyclic aromatic hydrocarbon contaminations in surface sediment and water from Gao-ping River, Taiwan. Water Res. 38, 1733–1744. Environment Canada and Ministère du développement durable, de I’Environment et des Parcs du Québec, 2007. Criteria for the assessment of sediment quality in Quebec and application frameworks: prevention, dredging and remediation. Québec: Library and Archives Canada Cataloguing in Publication, pp. 1–39. Filho, P.S., Luza, L.P., Betemps, G.B., Caramão, E.B., 2012. Evaluation of surface sediment contamination by polycyclic aromatic hydrocarbons in the ‘‘Saco do Laranjal’’-(Patos Lagoon, Brazil). Mar. Pollut. Bull. 64, 1933–1937. Hartmann, P.C., Quinn, J.G., Cairns, R.W., King, J.W., 2004. The distribution and sources of polycyclic aromatic hydrocarbons in Narragansett Bay surface sediments. Mar. Pollut. Bull. 48, 351–358. Heemken, O.P., Stachel, B., Theobald, N., Wenclawiak, B.W., 2000. Temporal variability of organic micropollutants in suspended particulate matter of the River Elbe at Hamburg and the River Mulde at Dessau, Germany. Arch. Environ. Contam. Toxicol. 38 (1), 11–31. Hu, N.J., Liu, J.H., Huang, P., Shi, X.F., Ma, D.Y., 2010. Distribution characteristics and ecological risk of polycyclic aromatic hydrocarbons in sediments from the western sea area of Liaodong Peninsula. J. China Univ. Petrol. 34 (5), 44–49. Hu, N.J., Shi, X.F., Liu, J.H., Huang, P., Zhu, A.M., Liu, Y.G., 2011. Distribution and origin of PAHs in the surface sediments of the Yellow River Estuary and its adjacent areas. Bull. Mineral. Petrol. Geochem. 29 (2), 157–163. Huang, G.P., Chen, Y.J., Lin, T., Tang, J.H., Liu, D.Y., Li, J., Zhang, G., 2011. The distribution and ecological risk of polycyclic aromatic hydrocarbons of surface
58
X. He et al. / Marine Pollution Bulletin 80 (2014) 52–58
sediments in the intertidal zone of Bohai Bay, China. Chin. Environ. Sci. 31 (11), 1856–1863. Huang, J.X., Yin, Y., 2007. Features and significance of heavy metal accumulation in tidal flat surface sediments of Guanhe Estuary. Environ. Protect. Sci. 33, 35–37 (in Chinese). Huang, W.X., Wang, Z.Y., Yan, W., 2012. Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments from Zhanjiang Bay and Leizhou Bay, South China. Mar. Pollut. Bull. 64, 1962–1969. Khim, J.S., Lee, K.T., Kannan, K., Villeneuve, D.L., Giesy, J.P., Koh, C.H., 2001. Trace organic contaminants in sediment and water from ulsan Bay and its vicinity. Arch. Environ. Contam. Toxicol. 40, 141–150. Lammel, G., Ghim, Y.S., Grados, A., Gao, H., Huhnerfuss, H., Lohmann, R., 2007. Levels of persistent organic pollutants in air in China and over the Yellow Sea. Atmos. Environ. 41, 452–464. Lang, Y.H., Wang, N.N., Gao, H.W., Bai, J., 2011. Distribution and risk assessment of polycyclic aromatic hydrocarbons (PAHs) from Liaohe estuarine wetland soils. Environ. Monit. Assess. 184, 5545–5552. Li, B.H., Feng, C.H., Li, X., Chen, Y.X., Niu, J.F., Shen, Z.Y., 2012. Spatial distribution and source apportionment of PAHs in surficial sediments of the Yangtze Estuary, China. Mar. Pollut. Bull. 64, 636–643. Li, Q.Z., Li, G.X., Luo, Z.X., Zhang, X., Yan, C.Z., 2009. Pollution characteristics and ecological risk assessment of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in sediment from Xiamen Bay. Environ. Chem. 28 (8), 869–875. Liu, L., Zhang, J.H., Hu, Y.Y., Huo, C., Wang, J.Y., 2011. Ecological risk assessment on polycyclic aromatic hydrocarbons in surface sediments of Dalian Bay. Mar. Environ. Sci. 30 (4), 477–480. Liu, W.Y., Lou, F., Yu, Z.Y., 2006. Analysis of river channel scour and silting evolution and natural condition of navigation channel in the Guanhe River Estuary area. Coast. Eng. 25, 14–21 (in Chinese). Liu, Y., Chen, L., Huang, Q.H., Li, W.Y., Tang, Y.J., Zhao, J.F., 2009. Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Huangpu River, Shanghai, China. Sci. Total Environ. 407, 2931–2938. Long, E.R., Field, L.J., MacDonald, D.D., 1998. Predicting toxicity in marine sediments with numerical sediment quality guidelines. Environ. Toxicol. Chem. 17, 714– 727. Long, E.R., Ingersoll, C.G., MacDonald, D.D., 2006. Calculation and uses of mean sediment quality guideline quotient: a critical review. Environ. Sci. Technol. 40, 1726–1736. Long, E.R., MacDonald, D.D., Smith, S.L., Calder, F.D., 1995. Incidence of adverse biological effects within ranges of chemical concentrations in marine and estuarine sediments. Environ. Manage. 19, 81–97. Lu, M., Zeng, D.C., Liao, Y., Tong, B., 2012. Distribution and characterization of organochlorine pesticides and polycyclic aromatic hydrocarbons in surface sediment from Poyang Lake, China. Sci. Total Environ. 433, 491–497. Luo, X.M., Liu, C.M., He, M.C., 2004. Sorption of polycyclic aromatic hydrocarbons (PAHs) by soils and sediments: a review. Ecol. Environ. Sci. 13, 394–398. MacDonald, D.D., Carr, R.S., Calder, F.D., Long, E.R., Ingersoll, C.G., 1996. Development and evaluation of sediment quality guidelines for Florida coastal waters. Ecotoxicology 5, 253–278. MacDonald, D.D., Ingersoll, C.G., Berger, T.A., 2000. Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Arch. Environ. Contam. Toxicol. 39, 20–31. Magi, E., Bianco, R., Ianni, C., Carro, M., 2002. Distribution of polycyclic aromatic hydrocarbons in the sediments of the Adriatic Sea. Environ. Pollut. 119, 91–98.
Marin-Morales, M.A., Leme, D.M., Mazzeo, D.E., 2009. A review of the hazardous effects of polycyclic aromatic hydrocarbons on living organisms. Polycyclic Aromatic Hydrocarbons: Pollution, Health Effects and Chemistry, 1–49. Men, B., He, M.C., Tan, L., Lin, C.Y., Quan, X.C., 2009. Distributions of polycyclic aromatic hydrocarbons in the Daliao River Estuary of Liaodong Bay, Bohai Sea (China). Mar. Pollut. Bull. 58, 818–826. Papadopoulou, D., Samara, C., 2002. Polycyclic aromatic hydrocarbon contamination and Lumistox (R) solvent extract toxicity of marine sediments in the North Aegean Sea, Greece. Environ. Toxicol. 17, 556–566. Pozo, K., Perra, G., Menchi, V., Urrutia, R., Parra, O., Rudolph, A., Focardi, S., 2011. Levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments from Lenga Estuary, central Chile. Mar. Pollut. Bull. 62, 1572–1576. Sicre, M.A., Marty, J.C., Saliot, A., Aparicio, X., Grimalt, J., Albaiges, J., 1987. Aliphatic and aromatic hydrocarbons in different sized aerosols over the Mediterranean Sea: occurrence and origin. Atmos. Environ. 21, 2247–2259. Soclo, H.H., Garrigues, P.H., Ewald, M., 2000. Origin of polycyclic aromatic hydrocarbons (PAHs) in coastal marine sediments: Case studies in Cotonou (Benin) and Aquitaine (France) areas. Mar. Pollut. Bull. 40, 387–396. Tamamura, S., Sato, T., Ota, Y., Wang, X., Tang, N., Hayakawa, K., 2007. Long-range transport of polycyclic aromatic hydrocarbons (PAHs) from the eastern Asian continent to Kanazawa, Japan with Asian dust. Atmos. Environ. 41, 2580–2593. Telli-Karakoc, F., Tolun, L., Henkelmann, B., Klimm, C., Okay, O., Schramm, K., 2002. Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in the Bay of Marmara sea: Izmit Bay. Environ. Pollut. 119, 383– 397. Wang, H.S., Zhang, C., Liang, P., Shao, D.D., Kang, Y., Wu, S.C., Wong, C.K., Wong, M.H., 2010. Characterization of PAHs in surface sediments of aquaculture farms around the Pearl River Delta. Ecotoxicol. Environ. Saf. 73, 900–906. Wang, X.C., Sun, S., Ma, H.Q., Liu, Y., 2006. Sources and distribution of aliphatic and polycyclic aromatic hydrocarbons in sediments of Jiaozhou Bay, Qingdao, China. Mar. Pollut. Bull. 52, 129–138. Warren, N., Allan, I.J., Carter, J.E., House, W.A., Parker, A., 2003. Pesticides and other micro-organic contaminants in freshwater sedimentary environments-a review. Appl. Geochem. 18, 159–194. Xu, S.Q., Ma, Q.M., Li, Z.L., Cheng, H.O., Gong, Z.B., 2011. Determination and risk assessment of polycyclic aromatic hydrocarbons in surface sediment from Jinzhou Bay, China. Environ. Chem. 30 (11), 1900–1905. Yang, S.L., 1999. Tidal wetland sedimentation in the Yangtze Delta. J. Coastal Res. 15, 1091–1099. Yuan, X.Y., Liu, H.Y., 2003. Chemical composition and heavy metal characteristics of sediments in the coast, northern Jiangsu Province. Volcanol. Min. Resour. 24, 204–210 (in Chinese).. Yunker, M.B., Macdonald, R.W., Vingarzan, R., Mitchell, R.H., Goyette, D., Sylvestre, S., 2002. PAHs in the Fraser river basin: a critical appraisal of PAH ratios as indicators of PAH source and composition. Org. Geochem. 33, 489–515. Zedeck, M.S., 1980. Polycyclic aromatic hydrocarbons: a review. J. Environ. Pathol. Toxicol. 3, 537–567. Zhang, J., Cai, L.Z., Yuan, D.X., Chen, M., 2004. Distribution and sources of polynuclear aromatic hydrocarbons in mangrove surficial sediments of Deep Bay, China. Mar. Pollut. Bull. 49, 479–486. Zhang, D.S., Zhang, C.K., 1993. Dynamic analysis of esturine deposition in Guanhe estury. J. Hohai Univ. 21, 29–37 (in Chinese). Zhuang, W.E., Wang, X.X., Yao, W.S., Yang, L., Song, X.K., Gong, Z.B., 2011. Distribution and source of polycyclic aromatic hydrocarbons in the surface sediments of Quanzhou Bay, China. Environ. Chem. 30 (5), 928–934.
Contents lists available at ScienceDirect
Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul
Distribution, sources and ecological risk assessment of PAHs in surface sediments from Guan River Estuary, China Xinran He a,b,⇑, Yong Pang a, Xiaojuan Song b, Binlin Chen c, Zhihua Feng d, Yuqin Ma b a
College of Environment, Hohai University, Nanjing 210098, China Lianyungang Environmental Monitoring Central Station, Lianyungang 222001, China c Lianyungang Environmental Protection Bureau, Lianyungang 222001, China d College of Marine Science & Technology, Huaihai Institute of Technology, Lianyungang 222005, China b
a r t i c l e
i n f o
Keywords: PAHs Surface sediment Ecological risk Sediment quality guidelines Molecular ratios Guan River Estuary
a b s t r a c t The contamination of surface sediments in Guan River Estuary, China, by polycyclic aromatic hydrocarbons (PAHs) has been fully investigated. Total concentrations of 21 PAHs ranged from 90 to 218 ng/g with an average of 132.7 ng/g, which is relatively low in comparison with other estuaries around the world. PAH concentrations appeared to be positively correlated with clay content and negatively correlated with sediment grain size. Source identification implied that the PAHs originated mainly from pyrolytic sources. However, source patterns may be continuously changed to a petrogenic origin due to the heavy ship traffic and continuous discharge of oily sewage in this area. The PAH levels were also compared with international Sediments Quality Guidelines and Sediments Quality Criteria, and the results indicated low negative effects for most individual PAHs. However, toxic effects related to FLO would occur occasionally in most locations in the estuary. Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction Polycyclic aromatic hydrocarbons (PAHs), a typical group of chemicals containing two or more aromatic rings, are prevalent in the environment. Because of their persistence, carcinogenicity, toxicity and mutagenicity (Zedeck, 1980; Marin-Morales et al., 2009), PAHs are of particular concern, and 16 priority PAHs are regulated by the United States Environmental Protection Agency (USEPA). For decades, the distribution and sources of PAHs have been the focus of numerous investigations (Soclo et al., 2000; Doong and Lin, 2004; Men et al., 2009; Chen and Chen, 2011; Barakat et al., 2011; Huang et al., 2012). PAHs can derive from natural sources, but anthropogenic activity is generally considered to be the major source (Baumard et al., 1998). Pyrogenic and petrogenic sources are two major origins of anthropogenic PAHs in the environment. Pyrogenic PAHs are formed as trace contaminants by the incomplete combustion of organic matter, such as wood, fossil fuels, asphalt and industrial waste. Petrogenic PAHs are usually contained in crude and refined petroleum (Liu et al., 2009). Once produced, PAHs can be transported to the marine environment through wastewater discharge, surface runoff, atmospheric ⇑ Corresponding author at: Lianyungang Environmental Monitoring Central Station, Lianyungang 222001, China. Tel.: +86 518 8552 1756. E-mail address: [email protected] (X. He). http://dx.doi.org/10.1016/j.marpolbul.2014.01.051 0025-326X/Ó 2014 Elsevier Ltd. All rights reserved.
deposition and other means, such as oil leaks (Heemken et al., 2000). In the marine environment, PAHs adhere tightly to sediments because of their high hydrophobicity and weak degradation (Warren et al., 2003). When the environmental conditions change, the adsorbed PAHs can be resuspended into the water via chemical and biological processes, which thus cause secondary pollution to the surroundings (Wang et al., 2010; Lu et al., 2012). Therefore, sediments act both as an important reservoir and as a secondary source for PAH contamination, and the investigation of sedimentary PAHs is needed to provide estimates of PAH inputs into marine areas. Guan River is the only natural river in northern Jiangsu Province with no water-gates on the main stream, which connects to the Beijing–Hangzhou Grand Canal and the Yangtze River in China (Liu et al., 2006). It flows into the Yellow Sea at the estuary, which facilitates trade with Japan and Korea. In terms of economic development, Guan River plays an important role in Jiangsu, equal to that of the Rhine in Germany and the Thames in England. In recent years, Guan River Estuary (GRE) has experienced a great deal of economic development, leading to an increasing risk of pollution by toxic chemicals. Previous studies have shown that with the increases of local sources, heavy metal pollution of surface sediments has become more and more serious in this area (Yuan and Liu, 2003; Huang and Yin, 2007; Chen et al., 2008). In the case of PAHs, both local sources and long-range atmospheric transport may play
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important roles in their distributions (Lammel et al., 2007; Tamamura et al., 2007). However, there is a scarcity of data on sedimentary PAHs, and this gap must be filled so that an effective environmental policy can be built upon sound scientific knowledge of the emission sources. The present work aimed to determine the levels and spatial distribution of PAHs in surface sediments in GRE and to identify the major sources of PAHs in this area. Special attention has also been paid to ecological risk assessment of PAHs because of their threats to human health. 2. Materials and methods 2.1. Sample collection Thirteen surface sediment samples were collected using a stainless steel grab sampler in April 2011. The sample locations are shown in Fig. 1. All samples were placed in dark glass bottles that had been pre-washed with n-hexane and kept in a refrigerator at 20 °C for further analysis.
Table 1 PAHs analyzed in this study. PAHs compounds
Abbreviation
Naphthalene Acenaphthylene Acenaphthene Fluorene Anthracene Phenanthrene Benzo(a)anthracene Chrysene Fluoranthene Pyrene Benzo(a)pyrene Dibenzo(a,h)anthracene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(g,h,i)perylene Indeno(1,2,3-cd)pyrene Benzo(c)phenanthrene Benzo(e)pyrene Benzo(j)fluoranthene 7,12-Dimethylbenz(a)anthracene 3-Methylcholanthrene
NAP ACY ACE FLO ANT PHE BaA CHR FLA PYR BaP DBahA BbF BkF BghiP IcdP BcP BeP BjF 7,12-DMBA 3-MECA
2.2. Chemicals A composite standard solution of 21 PAHs (Table 1) at 2000 mg/ L was obtained from AccuStandard Chem. Co. (USA). Deuterated PAH internal standard solutions (ACE-d10, PHE-d10, CHR-d12 and perylene-d12) at 4000 mg/L and surrogate standard solutions (2fluorobiphenyl and 4-terphenyl-d14) at 2000 mg/L were also purchased from AccuStandard. A certified reference material (CRM) sample was obtained from National Institute of Standards and Technology (NIST, SRM 1941). All solvents used for sample processing and analysis were HPLC grade from Tedia Co. (USA). Deionized water was produced by a Milli-Q system (Millipore Co., USA). Analytical grade anhydrous sodium sulfate was also used. 2.3. Sample preparation and analysis For PAH analysis, sediments were freeze-dried, crushed into fine powders, and passed through an 80-mesh sieve. Sieved samples of 10 g each were mixed with anhydrous sodium sulfate and Soxhlet-extracted with 80 ml hexane/acetone (1:1 v/v) for 24 h. Prior to analysis, internal standard solutions were added to each
extract, which was then cleaned-up by Gel Permeation Chromatography (LC-Tech, ultra 10836). GPC was carried out with a column of 500 mm 25 mm i.d. filled with 20 g of biobeads. As the mobile phase, chloroform was used at a flow rate of 5 mL min 1. The extract was rinsed out under 180 mbar and collected between 1600 and 2200 s. The extract volume was further reduced to 1.0 ml using a purified nitrogen stream and sealed in an amber vial for analysis. The concentrated extract was analyzed by gas chromatographymass spectrometry (GC–MS) using an Agilent 7890 GC and an Agilent 5975C MS with a DB-5MS capillary column (30 m 0.25 mm i.d., 0.25-lm film thickness). An aliquot of 1.0 lL sample extract was injected into the GC–MS with split stream sampling (split ratio: 10:1). The oven programme maintained the temperature at 50 °C for 1 min, then increased it from 50 to 180 °C at 4 °C/min and from 180 to 280 °C at 15 °C/min, and finally held it constant for 5 min. Helium was used as the carrier gas at a flow rate of 1.0 mL/min. The injector temperature was maintained at 250 °C. An electron impact ion source (EI) with electron energy of 70 eV was used for the MS, and the mass range scanned was from 50
Fig. 1. Map of sampling sites in GRE.
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to 500 amu under selected ion monitoring mode. The ion source, quadrupole and transfer line temperatures were held at 230, 150 and 280 °C, respectively. Identification of individual PAHs was based on the selected ions and the comparison of retention time between samples and the standard solution. In addition, the granularity of the sediment was analyzed using a Laser Particle Size Analyzer (Malvern 2000, England). Prior to analysis, organic materials were removed from sediment by treatment with hydrogen peroxide. 2.4. Quality assurance and quality control Analysis of the set of samples was accompanied by procedural blanks (solvent), spiked blanks (standards spiked into solvent), sample duplicates, and a CRM sample, all of which were carried through the entire analytical procedure in a manner identical to that used for the samples. Procedural blanks showed no detectable amounts of PAHs. Recoveries in matrix spikes were 75–120%. Relative percent difference (RPD) of duplicate samples was less than 25%. Recoveries in the CRM sample were between 77% and 105% of the certified values. One tenth of the samples were spiked with surrogates prior to extraction, with mean recoveries ranging from 75% to 83%. PAHs were quantified using the internal calibration method based on five-point calibration curves for individual compounds. The response factors based on calibration curves showed acceptable relative standard deviation (RSD) values (lower than 20%). The detection limits were estimated from a signal-to-noise ratio of 3:1 in blank samples (n = 7) and ranged from 0.1 to 0.9 ng/g for individual PAH compounds. All results were expressed on a dry weight basis. Glassware was washed with n-hexane and dried in an oven at 105 °C prior to use. Other materials were prewashed with ultrapure water and acetone. 3. Results and discussion 3.1. Level and spatial distribution of PAHs The concentrations of PAHs in surface sediments of GRE are summarized in Table 2, and the spatial distribution patterns are depicted
in Fig. 2. TPAHs, defined as the total concentration of 21 PAHs, ranged from 90 to 218 ng/g with a mean value of 132.7 ng/g. The total concentration of 16 priority PAHs ranged from 43 to 169 ng/g with a mean value of 104.2 ng/g. 9 PAHs (ACY, ACE, FLO, PHE, ANT, FLA, PYR, BbF and BkF) were detected at all of the stations, and the remaining 12 PAHs were detected at most of the stations. The average detection frequency of individual PAH compounds in surface sediments at 13 monitoring sites was up to 99.3%. As shown in Fig. 2, the spatial distribution of TPAHs was very similar to that of 16 PAHs. The higher concentrations were observed at stations near the entrance of GRE (H07 and H05), whilst the lower concentrations were generally found outside the entrance or beyond the nearshore region (H02, H03 and H08), suggesting that the amounts of PAHs were related to urban runoff and sewage discharges. In addition, tidal current might also influence the distribution of PAHs. Lower concentrations of PAHs at H10 or H11 might be due to higher tidal currents with less sediment deposition than H07 (Zhang and Zhang, 1993). Previous studies have shown that concentrations of PAHs in sediments are influenced by a number of factors including total organic carbon (TOC) content, mean sediment grain size, clay content, currents and so on (Yang, 1999; Luo et al., 2004). Generally, smaller particles exhibit a higher surface-to-volume ratio than larger ones and consequently have higher organic carbon content. Thus, the content of the adsorbed contaminants is often higher (Chiou et al., 1998). As shown in Fig. 3, TPAHs in sediments in GRE were positively correlated with clay content and negatively correlated with mean sediment grain size (samples collected at H01 to H07 were calculated for showing the correlations). Huang et al. (2012) also found significant positive correlations between total PAHs and TOC or silt–clay content in Zhanjiang Bay and Leizhou Bay in China. Therefore, particle size and clay content both play an important role in the distribution of PAHs in surface sediments of GRE. A comparison of PAH concentrations in surface sediments collected from different estuaries and bays in China and abroad is given in Table 3. The levels of sediment contamination by PAHs can be classified into four categories: (a) low, 0–100 ng/g; (b) moderate, 100–1000 ng/g; (c) high, 1000–5000 ng/g and (d) very high,
Table 2 Measured concentrations (ng/g) of PAHs in surface sediments from GRE. H01 NAP ACY ACE FLO PHE ANT FLA PYR BaA CHR BcP 7,12-DMBA BbF BkF BaP DBahA BeP BjF 3-MECA IcdP BghiP 2–3-ring PAHs 4–6-ring PAHs 16 PAHs TPAHs a b
1.0 12.0 2.0 26.0 3.0 3.0 3.0 1.0 1.0 1.0 ND ND 36.0 20.0 ND 1.0 ND ND ND 17.0 2.0 47.0 82.0 129 129
H02
H03
H04
H05
H06
H07
H08
H09
H10
H11
H12
H13
MDLa
1.0 6.0 11.0 34.0 1.0 1.0 2.0 1.0 ND 1.0 2.0 2.0 1.0 1.0 ND 1.0 13.0 ND 5.0 13.0 1.0 54.0 43.0 75.0 97.0
b
1.0 4.0 9.0 1.0 1.0 3.0 2.0 1.0 1.0 ND 2.0 1.0 12.0 1.0 1.0 1.0 43.0 2.0 8.0 2.0 3.0 19.0 80.0 43.0 99.0
17.0 12.0 6.0 25.0 3.0 2.0 2.0 2.0 1.0 2.0 1.0 2.0 38.0 8.0 3.0 16.0 15.0 3.0 6.0 ND ND 65.0 99.0 137 164
5.0 7.0 8.0 22.0 1.0 3.0 2.0 1.0 1.0 1.0 1.0 1.0 30.0 26.0 1.0 2.0 20.0 1.0 6.0 ND ND 46.0 93.0 110 139
27.0 4.0 8.0 31.0 1.0 4.0 2.0 2.0 1.0 1.0 ND 2.0 31.0 20.0 1.0 25.0 35.0 1.0 11.0 11.0 ND 75.0 143 169 218
5.0 8.0 3.0 3.0 2.0 1.0 3.0 1.0 ND 1.0 1.0 ND 19.0 2.0 1.0 2.0 20.0 1.0 13.0 3.0 1.0 22.0 68.0 55.0 90.0
7.0 14.0 5.0 26.0 2.0 1.0 2.0 1.0 2.0 1.0 2.0 2.0 30.0 7.0 2.0 3.0 20.0 3.0 3.0 1.0 1.0 55.0 80.0 105 135
14.0 12.0 8.0 22.0 2.0 3.0 3.0 1.0 1.0 1.0 1.0 1.0 26.0 9.0 2.0 15.0 21.0 3.0 4.0 1.0 ND 61.0 89.0 120 150
18.0 8.0 10.0 32.0 4.0 2.0 2.0 1.0 1.0 1.0 2.0 1.0 32.0 21.0 1.0 8.0 12.0 2.0 3.0 2.0 ND 74.0 89.0 143 163
14.0 5.0 7.0 19.0 1.0 2.0 2.0 1.0 1.0 1.0 ND 1.0 18.0 14.0 3.0 7.0 21.0 2.0 2.0 3.0 1.0 48.0 77.0 99.0 125
3.0 9.0 6.0 22.0 1.0 3.0 2.0 2.0 2.0 2.0 1.0 1.0 23.0 9.0 2.0 13.0 17.0 2.0 2.0 4.0 1.0 44.0 83.0 104 127
0.2 0.5 0.6 0.3 0.9 0.9 0.8 0.7 0.2 0.2 0.5 0.8 0.3 0.4 0.4 0.2 0.3 0.5 0.1 0.2 0.1
MDL: method detection limit. ND: not detected and indicates 0 ng/g.
ND 4.0 8.0 33.0 1.0 1.0 1.0 5.0 2.0 2.0 1.0 1.0 1.0 2.0 1.0 ND 18.0 1.0 3.0 4.0 1.0 47.0 43.0 66.0 90.0
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PAHs did not vary much from one sampling site to another, indicating similar PAH sources over the whole area. At most of the stations, the 5-ring PAHs were the most abundant, accounting for an average of 50.8% of the total PAHs. The 3-ring PAHs followed, with an average of 32.4%. Both the higher molecular compounds (5-ring PAHs) and lower molecular compounds were representative of the total PAH compounds in GRE. 3.3. Source apportionment of PAHs
Fig. 2. Distribution of TPAHs and 16 PAHs.
>5000 ng/g (Baumard et al., 1998). The PAH pollution level in GRE was low to moderate. The mean concentration of 16 PAHs was only slightly higher than that of Leizhou Bay, and it was lower than in most other bays shown in Table 3. The comparisons suggest that current contamination levels of PAHs in GRE are relatively low compared to other estuaries in China and around the world. 3.2. Composition of PAHs The composition patterns of PAHs by ring size in surface sediments of GRE are shown in Fig. 4. The percentage composition of
Recognition of PAH sources is necessary for control of their input and for allocating responsibility for remedial activities. A number of studies have demonstrated the practicability of using PAH isomeric ratios in source apportionment (Sicre et al., 1987; Budzinski et al., 1997; Soclo et al., 2000; Magi et al., 2002). In the present study, the ratios of low molecular weight PAHs (LMW) to high molecular weight PAHs (HMW), PHE/ANT and FLA/PYR were used to identify the PAH sources. The majority of PAHs in marine sediments originate from pyrogenic or petrogenic sources. Pyrolytic PAHs are produced during incomplete combustion of carbon, wood and fossil fuels, and they are characterized by compounds with four or more aromatic rings. In contrast, petrogenic PAHs contain only two or three aromatic rings (Soclo et al., 2000; Wang et al., 2006). Therefore, the ratio of LMW to HMW has been used to distinguish pyrogenic (1) sources. Table 4 shows the ratios of LMW/
Fig. 3. Correlation plots of TPAHs vs. clay content and mean sediment grain size.
Table 3 A comparison of PAH concentrations (ng/g) in surface sediments from different locations around the world.
a
Location
na
Range
Mean
References
Leizhou Bay, China GRE, China Yellow River Estuary, China Bohai Bay, China Liaodong Peninsula, China Yangtze Estuary, China Jinzhou Bay, China Zhanjiang Bay, China Quanzhou Bay, China Rizhao Coastal, China Xiamen Bay, China Daliao Estuary, China Liaohe Estuary, China Dalian Bay, China Narragansett Bay, USA Izmit Bay, Marmara Sea Ulsan bay, Korea Aegean sea, Greek Adriatic Sea, Italy Mediterranean, Egypt Saco do Laranjal, Brazil Lenga Estuary, Chile
16 16 16 16 16 16 16 16 16 16 16 16 16 16 44 16
21.72–319.61 43–169 111.3–204.8 54.6–202.3 144.5–205.3 90.14–502.12 133.44–593.91 41.96–933.90 182.8–721.1 79.3–853 203.98–1590.47 276.26–1606.89 704.7–1804.5 157–20855 569–2.16 105 3.0 104–1.67 106 17–3100 45–148 24.1–501.1 3.51–14100 7.3–93.2 290–6118
103.91 104.2 115.8 140.0 173.0 221.18 262.15 315.98 353.8 360 670 743.03 1001.9 7642 21100 6.01 105 – – – 786
Huang et al. (2012) This study Hu et al. (2011) Huang et al. (2011) Hu et al. (2010) Li et al. (2012) Xu et al. (2011) Huang et al. (2012) Zhuang et al. (2011) Chen et al. (2012) Li et al. (2009) Men et al. (2009) Lang et al. (2011) Liu et al. (2011) Hartmann et al. (2004) Telli-Karakoc et al. (2002) Khim et al. (2001) Papadopoulou and Samara (2002) Magi et al. (2002) Barakat et al. (2011) Filho et al. (2012) Pozo et al. (2011)
16 16 16
n: Number of PAH compounds analyzed in each study.
2025
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X. He et al. / Marine Pollution Bulletin 80 (2014) 52–58
100% 80% 60% 40% 20% 0% H01 2-ring PAHs
H02 H03 H04
H05 H06 H07 H08
3-ring PAHs
4-ring PAHs
H09 H10 H11 5-ring PAHs
H12 H13 6-ring PAHs
Fig. 4. The composition pattern of PAHs by ring size in surface sediments from GRE.
HMW, which were 1, indicating that petrogenic sources could occasionally contribute to PAH contamination in this area. The PHE/ANT ratio can also provide useful information for distinguishing PAHs of various origins (Budzinski et al., 1997; Yunker et al., 2002). PHE and ANT are two structural isomers, with PHE being the more thermodynamically stable. Therefore, a higher PHE/ANT ratio is observed in petrogenic pollution, and a lower ratio in pyrolytic pollution. Sediments with PHE/ANT > 10 indicate petrogenic contamination, while PHE/ANT < 10 are typical of pyrolytic sources. In the present study, the PHE/ANT ratios were in the range 0.25–2.00 (Table 4), clearly indicating a pyrolytic source. Similar results were observed for the FLA/PYR ratios. It is assumed that petroleum often contains more thermodynamically stable compounds such as NAP, FLO, PHE and CHR, while FLA and PYR are usually the most abundant compounds in pyrolytic PAHs (Sicre et al., 1987; Magi et al., 2002; Zhang et al., 2004). Therefore, FLA/PYR ratios greater than 1 indicate pyrolytic origin, while values less than 1 are attributed to petrogenic sources (Magi et al., 2002). As shown in Table 4, the ratio of FLA/PYR was larger than 1 at 9 sites, suggesting predominantly pyrolytic sources. The ratio was lower than 1 at site H02, indicating that petrogenic sources might also contribute to PAH contamination in this area. In conclusion, the three ratios present consistent results. Pyrogenic PAHs were dominant in the sediments in this area. GRE is a popular site for tourists, and ship traffic may contribute to PAH input in this area. Pyrolytic PAHs may come from the exhaust of diesel engines. In addition, heavy traffic and coal heating could also result in the increase of PAH loadings through atmospheric deposition and freshwater runoff. In some parts of the area, petrogenic PAHs may contribute to PAH contaminations, which could come from oil/gas/diesel spills and oily sewage discharges from ambient estuary.
freshwater and marine environments (MacDonald et al., 2000; Long et al., 2006). BEDS contains various types of data that can be used to establish links between the concentration of a given chemical and its biological effect. These data come from field studies, spiked-sediment toxicity tests and equilibrium partitioning models. SQGs provide two target values: effects range low (ERL) and effects range median (ERM), which are established using the 10th and 50th percentiles, respectively, in a database of increasing concentrations associated with adverse biological effects. PAH concentrations lower than ERL are considered not to be harmful to organisms, while concentrations higher than ERM are considered to be harmful frequently. PAHs with concentrations between ERL and ERM are considered to be harmful occasionally (Long et al., 1995, 1998; MacDonald et al., 1996). Table 5 presents the toxicity guidelines for 12 individual PAHs and identifies the stations in the three different ranges defined by ERL and ERM. Concentrations of individual PAHs at stations H04 and H08 were all below the ERL, suggesting that biological effects at these two stations would rarely occur. However, in the case of the other 11 stations, concentrations of FLO were between the ERL and ERM, which indicates that biological effects related to FLO would occur occasionally at these stations.
3.4.2. Sediment quality criteria (SQC) SQC are based on SQGs combined with consideration of natural, economic, social, technical and other conditions. We have not established any related standards for PAHs in China. In the present study, we assessed PAH contamination levels in surface sediments of GRE according to the SQC used in Canada (ECM, 2007). This standard contains five effect levels: the rare effect level (REL), the threshold effect level (TEL), the occasional effect level (OEL), the probable effect level (PEL) and the frequent effect level (FEL). These five values for 12 PAHs are presented in Table 6, which could be applied in developing strategies for environmental management (including restoration, dredging, pollution control). Biological risks of 12 PAH compounds in surface sediments of GRE were also evaluated according to the sediment quality standard applied in Canada (ECM, 2007). Table 7 shows the sampling sites at which concentrations of at least one PAH were greater than the lowest level. The results show that PAH concentrations at all 13 sampling sites of GRE were between TEL and OEL, indicating that adverse effects of PAHs in this area are unlikely. For the time being, further assessment of the environmental risks associated with PAHs in this area is not necessary, and there are no surface sediments in need of remediation. However, long-term monitoring should be undertaken in order to detect new contamination, and investigation of the origin and environmental impacts of PAHs should be carried out in depth.
4. Conclusions 3.4. Risk assessments of PAHs in surface sediments 3.4.1. Sediment quality guidelines (SQGs) SQGs developed on the basis of Biological Effects Database for Sediments (BEDS) are very useful for sediment assessments in
PAH concentrations in surface sediments of GRE are relatively low at the present time in comparison with other estuaries worldwide. The spatial distributions were determined by considering different properties of the sediments, and it was found that con-
Table 4 Characteristic values of LMW/HMW, PHE/ANT and FLA/PYR at different sampling sites in GRE. Sampling sites
LMW/HMWa PHE/ANT FLA/PYR a
H01
H02
H03
H04
H05
H06
H07
H8
H9
H10
H11
H12
H13
0.57 1.00 3.00
1.26 1.00 2.00
1.09 1.00 0.20
0.24 0.33 2.00
0.66 1.50 1.00
0.49 0.33 2.00
0.52 0.25 1.00
0.32 2.00 3.00
0.69 2.00 2.00
0.69 0.67 3.00
0.83 2.00 2.00
0.62 0.50 2.00
0.53 0.33 1.00
LMW/HMW: concentration ratio of 2–3-ring PAHs to 4–6-ring PAHs.
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X. He et al. / Marine Pollution Bulletin 80 (2014) 52–58 Table 5 Concentration ranges of PAHs in sediments from GRE and toxicity guidelines. Compound
ACE ACY ANT FLO NAP PHE LMW PAHs BaA BaP CHR DBahA FLA PYR HMW PAHs Total PAHs a
SQGa (ng/g)
Concentration range (ng/g)
ERL
ERM
16 44 85.3 19 160 240 552 261 430 384 63.4 600 665 1 700 4 022
500 640 1 100 540 2 100 1 500 3 160 1 600 1 600 2 800 260 5 100 2 600 9 600 44 792
Sites
2.0–11.0 4.0–14.0 1.0–4.0 1.0–34.0 ND-27.0 1.0–4.0 19–75 ND-2.0 ND-3.0 ND-2.0 ND-25.0 1.0–3.0 1.0–5.0 43–143 90–218
ERM
All sites All sites All sites H04 and H08 All sites All sites All sites All sites All sites All sites All sites All sites All sites All sites All sites
– – – H01, H02, H03, H05, H06, H07, H09, H10, H11, H12 and H13 – – – – – – – – – – –
– – – – – – – – – – – – – – –
SQG values taken from Long et al. (1995) and MacDonald et al. (1996).
Table 6 Criteria for the assessment of marine sediment quality relative to PAHs in Canada (ng/ g). PAHs
REL
TEL
OEL
PEL
FEL
ACE ACY ANT BaA BaP CHR DBahA FLA FLO NAP PHE PYR
3.7 3.3 16 27 34 37 3.3 27 10 17 23 41
6.7 5.9 47 75 89 110 6.2 110 21 35 87 150
21 31 110 280 230 300 43 500 61 120 250 420
89 130 240 690 760 850 140 1500 140 390 540 1400
940 340 1100 1900 1700 2200 200 4200 1200 1200 2100 3800
Table 7 Risk assessments of PAHs according to the sediment quality criteria. Range of sediment quality critera
Sampling sites
Higher than FEL Between PEL and FEL Between OEL and PEL Between TEL and OEL Between REL and TEL Lower than REL
– – – All sites – –
centrations of TPAHs were positively correlated with clay content and negatively correlated with mean sediment grain size. Based on selected PAH ratios, it was concluded that the pyrogenic PAHs were dominant in the sediments and were probably due to vessel and vehicle exhaust from diesel engines, as well as coal combustion from domestic heating systems. In some parts of the area, petroleum sources from fuel spills and oily sewage discharges might also contribute to PAH pollution. It is important to emphasize that the source patterns of PAHs may change continuously because of the intense traffic in this area. The ecotoxicological risk evaluation based on international SQGs and SQC indicated that the probability of negative effects caused by 11 PAH compounds is low. However, toxic effects related to FLO would occur occasionally in most locations in the estuary. Results obtained in the present study have provided useful information to evaluate PAH contamination levels in surface sediments of GRE, which is an economically important region in China due to industry and tourism.
Acknowledgements This work was supported by the National Natural Science Foundation of China (51179053), the Science and Technology Development Project in Lianyungang City (SH1113) and the Environmental Technology Project in Jiangsu Province (2010043).
References Barakat, A.O., Mostafa, A., Wade, T.L., Sweet, S.T., ElSayed, N.B., 2011. Distribution and characteristics of PAHs in sediments from the Mediterranean coastal environment of Egypt. Mar. Pollut. Bull. 62, 1969–1978. Baumard, P., Budzinski, H., Garrigues, P., 1998. Polycyclic aromatic hydrocarbons in sediments and mussels of the Western Mediterranean Sea. Environ. Chem. 7, 765–776. Budzinski, H., Jones, I., Bellocq, J., Pierrad, C., Garrigues, P., 1997. Evaluation of sediment contamination by polycyclic aromatic hydrocarbons in the Gironde estuary. Mar. Chem. 58, 85–97. Chen, B.L., He, X.R., Wang, T.Y., Liu, H., 2008. Heavy metals pollution and potential ecological risk in sediment of Lianyungang sea area. Mar. Environ. Sci. 27, 246– 249 (in Chinese). Chen, C.W., Chen, C.F., 2011. Distribution, origin, and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in sediments of Kaohsiung Harbor. Taiwan. Mar. Pollut. Bull. 63, 417–423. Chen, H.Y., Teng, Y.G., Wang, J.S., 2012. Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Rizhao coastal area (China) using diagnostic ratios and factor analysis with nonnegative constraints. Sci. Total Environ. 414, 293–300. Chiou, C.T., McGroddy, S.E., Kile, D.E., 1998. Partition characteristics of polycyclic aromatic hydrocarbons on soilsand sediments. Environ. Sci. Technol. 32, 264– 269. Doong, R.A., Lin, Y.T., 2004. Characterization and distribution of polycyclic aromatic hydrocarbon contaminations in surface sediment and water from Gao-ping River, Taiwan. Water Res. 38, 1733–1744. Environment Canada and Ministère du développement durable, de I’Environment et des Parcs du Québec, 2007. Criteria for the assessment of sediment quality in Quebec and application frameworks: prevention, dredging and remediation. Québec: Library and Archives Canada Cataloguing in Publication, pp. 1–39. Filho, P.S., Luza, L.P., Betemps, G.B., Caramão, E.B., 2012. Evaluation of surface sediment contamination by polycyclic aromatic hydrocarbons in the ‘‘Saco do Laranjal’’-(Patos Lagoon, Brazil). Mar. Pollut. Bull. 64, 1933–1937. Hartmann, P.C., Quinn, J.G., Cairns, R.W., King, J.W., 2004. The distribution and sources of polycyclic aromatic hydrocarbons in Narragansett Bay surface sediments. Mar. Pollut. Bull. 48, 351–358. Heemken, O.P., Stachel, B., Theobald, N., Wenclawiak, B.W., 2000. Temporal variability of organic micropollutants in suspended particulate matter of the River Elbe at Hamburg and the River Mulde at Dessau, Germany. Arch. Environ. Contam. Toxicol. 38 (1), 11–31. Hu, N.J., Liu, J.H., Huang, P., Shi, X.F., Ma, D.Y., 2010. Distribution characteristics and ecological risk of polycyclic aromatic hydrocarbons in sediments from the western sea area of Liaodong Peninsula. J. China Univ. Petrol. 34 (5), 44–49. Hu, N.J., Shi, X.F., Liu, J.H., Huang, P., Zhu, A.M., Liu, Y.G., 2011. Distribution and origin of PAHs in the surface sediments of the Yellow River Estuary and its adjacent areas. Bull. Mineral. Petrol. Geochem. 29 (2), 157–163. Huang, G.P., Chen, Y.J., Lin, T., Tang, J.H., Liu, D.Y., Li, J., Zhang, G., 2011. The distribution and ecological risk of polycyclic aromatic hydrocarbons of surface
58
X. He et al. / Marine Pollution Bulletin 80 (2014) 52–58
sediments in the intertidal zone of Bohai Bay, China. Chin. Environ. Sci. 31 (11), 1856–1863. Huang, J.X., Yin, Y., 2007. Features and significance of heavy metal accumulation in tidal flat surface sediments of Guanhe Estuary. Environ. Protect. Sci. 33, 35–37 (in Chinese). Huang, W.X., Wang, Z.Y., Yan, W., 2012. Distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments from Zhanjiang Bay and Leizhou Bay, South China. Mar. Pollut. Bull. 64, 1962–1969. Khim, J.S., Lee, K.T., Kannan, K., Villeneuve, D.L., Giesy, J.P., Koh, C.H., 2001. Trace organic contaminants in sediment and water from ulsan Bay and its vicinity. Arch. Environ. Contam. Toxicol. 40, 141–150. Lammel, G., Ghim, Y.S., Grados, A., Gao, H., Huhnerfuss, H., Lohmann, R., 2007. Levels of persistent organic pollutants in air in China and over the Yellow Sea. Atmos. Environ. 41, 452–464. Lang, Y.H., Wang, N.N., Gao, H.W., Bai, J., 2011. Distribution and risk assessment of polycyclic aromatic hydrocarbons (PAHs) from Liaohe estuarine wetland soils. Environ. Monit. Assess. 184, 5545–5552. Li, B.H., Feng, C.H., Li, X., Chen, Y.X., Niu, J.F., Shen, Z.Y., 2012. Spatial distribution and source apportionment of PAHs in surficial sediments of the Yangtze Estuary, China. Mar. Pollut. Bull. 64, 636–643. Li, Q.Z., Li, G.X., Luo, Z.X., Zhang, X., Yan, C.Z., 2009. Pollution characteristics and ecological risk assessment of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in sediment from Xiamen Bay. Environ. Chem. 28 (8), 869–875. Liu, L., Zhang, J.H., Hu, Y.Y., Huo, C., Wang, J.Y., 2011. Ecological risk assessment on polycyclic aromatic hydrocarbons in surface sediments of Dalian Bay. Mar. Environ. Sci. 30 (4), 477–480. Liu, W.Y., Lou, F., Yu, Z.Y., 2006. Analysis of river channel scour and silting evolution and natural condition of navigation channel in the Guanhe River Estuary area. Coast. Eng. 25, 14–21 (in Chinese). Liu, Y., Chen, L., Huang, Q.H., Li, W.Y., Tang, Y.J., Zhao, J.F., 2009. Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Huangpu River, Shanghai, China. Sci. Total Environ. 407, 2931–2938. Long, E.R., Field, L.J., MacDonald, D.D., 1998. Predicting toxicity in marine sediments with numerical sediment quality guidelines. Environ. Toxicol. Chem. 17, 714– 727. Long, E.R., Ingersoll, C.G., MacDonald, D.D., 2006. Calculation and uses of mean sediment quality guideline quotient: a critical review. Environ. Sci. Technol. 40, 1726–1736. Long, E.R., MacDonald, D.D., Smith, S.L., Calder, F.D., 1995. Incidence of adverse biological effects within ranges of chemical concentrations in marine and estuarine sediments. Environ. Manage. 19, 81–97. Lu, M., Zeng, D.C., Liao, Y., Tong, B., 2012. Distribution and characterization of organochlorine pesticides and polycyclic aromatic hydrocarbons in surface sediment from Poyang Lake, China. Sci. Total Environ. 433, 491–497. Luo, X.M., Liu, C.M., He, M.C., 2004. Sorption of polycyclic aromatic hydrocarbons (PAHs) by soils and sediments: a review. Ecol. Environ. Sci. 13, 394–398. MacDonald, D.D., Carr, R.S., Calder, F.D., Long, E.R., Ingersoll, C.G., 1996. Development and evaluation of sediment quality guidelines for Florida coastal waters. Ecotoxicology 5, 253–278. MacDonald, D.D., Ingersoll, C.G., Berger, T.A., 2000. Development and evaluation of consensus-based sediment quality guidelines for freshwater ecosystems. Arch. Environ. Contam. Toxicol. 39, 20–31. Magi, E., Bianco, R., Ianni, C., Carro, M., 2002. Distribution of polycyclic aromatic hydrocarbons in the sediments of the Adriatic Sea. Environ. Pollut. 119, 91–98.
Marin-Morales, M.A., Leme, D.M., Mazzeo, D.E., 2009. A review of the hazardous effects of polycyclic aromatic hydrocarbons on living organisms. Polycyclic Aromatic Hydrocarbons: Pollution, Health Effects and Chemistry, 1–49. Men, B., He, M.C., Tan, L., Lin, C.Y., Quan, X.C., 2009. Distributions of polycyclic aromatic hydrocarbons in the Daliao River Estuary of Liaodong Bay, Bohai Sea (China). Mar. Pollut. Bull. 58, 818–826. Papadopoulou, D., Samara, C., 2002. Polycyclic aromatic hydrocarbon contamination and Lumistox (R) solvent extract toxicity of marine sediments in the North Aegean Sea, Greece. Environ. Toxicol. 17, 556–566. Pozo, K., Perra, G., Menchi, V., Urrutia, R., Parra, O., Rudolph, A., Focardi, S., 2011. Levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in sediments from Lenga Estuary, central Chile. Mar. Pollut. Bull. 62, 1572–1576. Sicre, M.A., Marty, J.C., Saliot, A., Aparicio, X., Grimalt, J., Albaiges, J., 1987. Aliphatic and aromatic hydrocarbons in different sized aerosols over the Mediterranean Sea: occurrence and origin. Atmos. Environ. 21, 2247–2259. Soclo, H.H., Garrigues, P.H., Ewald, M., 2000. Origin of polycyclic aromatic hydrocarbons (PAHs) in coastal marine sediments: Case studies in Cotonou (Benin) and Aquitaine (France) areas. Mar. Pollut. Bull. 40, 387–396. Tamamura, S., Sato, T., Ota, Y., Wang, X., Tang, N., Hayakawa, K., 2007. Long-range transport of polycyclic aromatic hydrocarbons (PAHs) from the eastern Asian continent to Kanazawa, Japan with Asian dust. Atmos. Environ. 41, 2580–2593. Telli-Karakoc, F., Tolun, L., Henkelmann, B., Klimm, C., Okay, O., Schramm, K., 2002. Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) distributions in the Bay of Marmara sea: Izmit Bay. Environ. Pollut. 119, 383– 397. Wang, H.S., Zhang, C., Liang, P., Shao, D.D., Kang, Y., Wu, S.C., Wong, C.K., Wong, M.H., 2010. Characterization of PAHs in surface sediments of aquaculture farms around the Pearl River Delta. Ecotoxicol. Environ. Saf. 73, 900–906. Wang, X.C., Sun, S., Ma, H.Q., Liu, Y., 2006. Sources and distribution of aliphatic and polycyclic aromatic hydrocarbons in sediments of Jiaozhou Bay, Qingdao, China. Mar. Pollut. Bull. 52, 129–138. Warren, N., Allan, I.J., Carter, J.E., House, W.A., Parker, A., 2003. Pesticides and other micro-organic contaminants in freshwater sedimentary environments-a review. Appl. Geochem. 18, 159–194. Xu, S.Q., Ma, Q.M., Li, Z.L., Cheng, H.O., Gong, Z.B., 2011. Determination and risk assessment of polycyclic aromatic hydrocarbons in surface sediment from Jinzhou Bay, China. Environ. Chem. 30 (11), 1900–1905. Yang, S.L., 1999. Tidal wetland sedimentation in the Yangtze Delta. J. Coastal Res. 15, 1091–1099. Yuan, X.Y., Liu, H.Y., 2003. Chemical composition and heavy metal characteristics of sediments in the coast, northern Jiangsu Province. Volcanol. Min. Resour. 24, 204–210 (in Chinese).. Yunker, M.B., Macdonald, R.W., Vingarzan, R., Mitchell, R.H., Goyette, D., Sylvestre, S., 2002. PAHs in the Fraser river basin: a critical appraisal of PAH ratios as indicators of PAH source and composition. Org. Geochem. 33, 489–515. Zedeck, M.S., 1980. Polycyclic aromatic hydrocarbons: a review. J. Environ. Pathol. Toxicol. 3, 537–567. Zhang, J., Cai, L.Z., Yuan, D.X., Chen, M., 2004. Distribution and sources of polynuclear aromatic hydrocarbons in mangrove surficial sediments of Deep Bay, China. Mar. Pollut. Bull. 49, 479–486. Zhang, D.S., Zhang, C.K., 1993. Dynamic analysis of esturine deposition in Guanhe estury. J. Hohai Univ. 21, 29–37 (in Chinese). Zhuang, W.E., Wang, X.X., Yao, W.S., Yang, L., Song, X.K., Gong, Z.B., 2011. Distribution and source of polycyclic aromatic hydrocarbons in the surface sediments of Quanzhou Bay, China. Environ. Chem. 30 (5), 928–934.
