PAHs in surface sediments from coastal and estuarine areas
Environ Geochem Health
DOI 10.1007/s10653-011-9445-8
PAHs in surface sediments from coastal and estuarine areas of the northern Bohai and Yellow Seas, China
Wentao Jiao • Tieyu Wang • Jong Seong Khim •
Wei Luo • Wenyou Hu • Jonathan E. Naile •
John P. Giesy • Yonglong Lu
Received: 18 April 2011 / Accepted: 8 December 2011
Ó Springer Science+Business Media B.V. 2011
Abstract Polycyclic aromatic hydrocarbon (PAH) concentrations and their risks in surface sediments
( n = 35) collected from coastal and estuarine areas of the northern Bohai and Yellow Seas, China, were investigated in 2008. Total concentrations of PAHs ranged from 52.3 to 1,870.6 ng/g dry weight. The greatest concentrations were observed in the Dou River of Tangshan where waste water from small factories is discharged into the river without treatment. At other locations, municipal sewage was the primary contributor of PAHs. Regional differences in concentrations of PAHs in sediments are related to human activities.
Concentrations of PAHs were significantly correlated with concentrations of organic carbon in sediments. The patterns of relative concentrations and types of PAHs observed and knowledge of the potential sources, as well as the results of a principal component analysis, are consistent with the primary sources of PAHs in sediments of the northern Bohai Sea and Yellow Sea, being derived from the high-temperature pyrolytic processes such as combustion of fossil fuel. While concentrations of PAHs at most locations did not exceed the effects range median stated by the numerical effectbased sediment quality guidelines of the United States, concentrations of PAHs at some locations were similar to or greater than the effects range low.
Keywords PAHs Sediment contamination
Ecological risk assessment Coastal areas
W. Jiao T. Wang W. Luo W. Hu Y. Lu (
&
)
State Key Laboratory of Urban and Regional Ecology,
Research Center for Eco-Environmental Sciences,
Chinese Academy of Sciences, Beijing 100085, China e-mail: yllu@rcees.ac.cn
J. S. Khim
Division of Environmental Science and Ecological
Engineering, Korea University, Seoul 136-713,
South Korea
J. E. Naile J. P. Giesy
Department of Veterinary Biomedical Sciences and
Toxicology Centre, University of Saskatchewan,
Saskatoon, SK S7J 5B3, Canada
Introduction
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic pollutants in the environment that are toxic and of concern in China (Edwards
; Long et al.
; Zhang et al.
). Emission of the 16 priority PAHs listed by US EPA in China have increased substantially from around 18,000 tons in
1980 to [ 25,000 tons in 2003 (Xu et al.
). PAHs are generated from incomplete combustion of carboncontaining fuels such as petroleum, oil, coal and wood
(Simoneit
1984 ; Mastral and Callen 2000 ; Sofowote
et al.
2008 ). Based on information for 2003, biomass
burning, domestic coal combustion, coking industry and petroleum combustion accounted for 60, 20, 16 and 3% of PAH emissions in China, respectively (Xu et al.
).
123
Due to continuous emissions and chemical properties, including chemical stability, semi-volatility and hydrophobicity, PAHs in aquatic systems can be accumulated in suspended particulate matter and sediment through disposal of liquid effluents, terrestrial runoff and leachate from numerous urban, industrial and agricultural activities, as well as atmospheric deposition (Thompson et al.
et al.
; Usenko et al.
into the sources and distributions of PAHs in sediments is useful when monitoring water quality and conducting ecological assessments so that sources can be eliminated or controlled (Nikolaou et al.
).
The northern Bohai and Yellow Seas are part of the
Pacific Ocean and located between the industrialized northeast coast of China and the Korean peninsula.
This area has been affected by growing populations, industrialization and rapid economic development.
The economic contribution of the Bohai Sea accounts for one-tenth of the gross domestic product of China, and the Bohai Sea is also traditionally known as a ‘fish storehouse’, ‘salt storehouse’ and ‘oil storehouse’. As the main receiving coastal ecosystems, the water and sediment in the northern Bohai and Yellow Seas are influenced by industrial discharges and partially treated domestic effluents from coastal and estuarine areas. The Yellow, Liaohe, Haihe, Luanhe and Daliaohe Rivers are the major freshwater sources discharging directly into the Bohai Sea. Untreated domestic wastewater, industrial wastewater, agricultural runoff, ship and boat traffic, oil transportation, oil spillage and atmospheric fallout are all potential sources of PAH contamination (Zhang et al.
Compared with the open sea, water exchange in the semi-enclosed area of Bohai Bay is relatively slow.
Consequentially, pollutants in sediments of this area tend to accumulate in sediment where degradation and outflow are relatively slow (Greenfield and Davis
; Zhang et al.
). The residence time for water in Bohai Bay has been estimated to be approximately 30 years, which leads to accumulation of pollutants in these seas (Ma et al.
2009a ). While distributions of PAHs in waters and
sediments of the northern Bohai and Yellow Seas have been investigated in several studies (Ma et al.
;
Wu et al.
; Liu et al.
; Bai et al.
), there has never been an assessment conducted at the regional level. Thus, it has been difficult to determine the ecological risks and identify
123
Environ Geochem Health sources so that remedial action plans could be developed. Therefore, it was deemed necessary to document its sedimentary PAHs data.
It was hypothesized that sources of emissions and other human activities determine regional differences in concentrations of PAHs in sediments along the coastal and estuarine areas of northern Bohai and
Huanghai Seas (CEANBYS). Results presented here were collected as part of a larger systematic investigation into concentrations and ecological risks of
PAHs in sediments from CEANBYS. The purposes of this study were to (1) determine concentrations of
PAHs in sediments from CEANBYS and investigate their regional differences, (2) identify possible sources and their relative contributions of PAHs to sediments and (3) evaluate the potential ecological risk of PAHs in sediments.
Materials and methods
Sample collection
Thirty-five surface (0–10 cm) sediment samples were collected from CEANBYS in October 2008. Figure
illustrated the distribution of sampling locations along coastal and estuarine areas of the northern Bohai and
Yellow Seas. There are eight major cities in the region including: Tangshan (TS) and Qinhuangdao (QH) in
Hebei Province, Huludao (HL), Jinzhou (JZ), Panjin
(PJ), Yinkou (YK), Dalian (DL) and Dandong (DD) in
Liaoning province. There are ten main estuaries flowing into the northern Bohai Sea and six main estuaries flowing into the northern Yellow Sea. The sediment samples collected from northern Bohai were numbered as TS1-7 in Tangshan, QH1-5 in Qinhuangdao, HL1-5 in Huludao, JZ1-5 in Jinzhou, PJ1-2 in
Panjin, YK1-3 in Yingkou and DL1-4 in Dalian.
Sediment samples collected from the northern shore of the Yellow Sea were numbered as: DL5-6 in Dalian and DD1-4 in Dandong (Table
Throughout the survey, a global positioning system
(GPS) was used to locate the sampling locations.
Surface sediments were collected by use of a trowel from the sedimentation basin close to the bank.
Representative samples were prepared by mixing five subsamples from the area of about 5 m
2
. Wet samples
(about 1 kg) were wrapped in precleaned, highdensity polypropylene boxes and transported to the
Environ Geochem Health
Fig. 1 Study area and sampling locations along coastal and estuarine areas of the northern Bohai and
Yellow Seas laboratory where they were lyophilized, homogenized and ground with a pestle and mortar, sieved using a
2-mm sieve (Nadal et al.
° C in precleaned glass jars until analysis.
Sample extraction and fractionation
PAHs were extracted, isolated and analyzed based on a previously published procedure (Jiao et al.
Briefly, 5.0 g of sediment samples was mixed with 2 g of anhydrous sodium sulfate and 1 g of activated copper. Each sample was spiked with a surrogate standard, phenanthrened10 (Supelco, Bellefonte, PA,
USA), and then extracted with 210 ml of methylene chloride for 48 h in a Soxhlet apparatus. The extract was concentrated to 2 ml by a rotary evaporator and solvent-exchanged to hexane. The hexane extract was fractionated, and interferences were removed using a silica gel column (Supelco). Sodium sulfate (1 cm) was added to the top of silica gel, and the column was eluted with 15 ml of n-hexane and 5 ml of methylene chloride/hexane (v/v = 3:7). The PAH fraction was concentrated to 1 ml under a gentle stream of nitrogen.
Sample analysis
Concentrations of PAHs in extracts were determined by an Agilent 6890 gas chromatograph (GC) equipped with a 5,973 mass selective detector (MSD) in selective ion monitoring (SIM) mode. A HP-5 fused silica capillary column (60 m 9 0.25 mm inner diameter 9 0.25
l m film thickness) was used with helium as the carrier gas at a constant flow rate of 1 ml/min.
Splitless injection of 1 l l of the extract was made using an autosampler. The GC oven temperature was programmed from 50 ° C (2 min) to 200 ° C (2 min) at
20 ° C/min, then to 240 ° C (2 min) at 5 ° C/min before reaching 290 ° C at 3 ° C/min and then held for 15 min.
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Environ Geochem Health
Table 1 Sample details including geographical description and surrounding activities of all sampling locations
Sampling Land use Remark
City Region Sites Agricultural Industrial Municipal Others Geographical description
Tangshan
Qinhuangdao
Huludao
Jinzhou
Panjin
Yingkou
Dalian
Dangdong
Dou River
Qinglong River
Shuanglong River
Luanhe River
Bohai Sea
Tianma Lake
Bohai Sea
Liugu River
Wuli River
Bohai Sea
Xiaoling River
Daling River
Shuangtaizi River
Bohai Sea
Daliao River
Bohai Sea
Bohai Sea
Fuzhou River
Bohai Sea
Biliu River
Bohai Sea
Dayang River
Yalu River
JZ4
JZ5
PJ1
PJ2
YK1
YK2
YK3
DL1
QH5
HL1
HL2
HL3
HL4
HL5
JZ2
JZ3
DL2
DL4
DL5
DL6
DD1
DD2
DD3
DD4
TS1
TS2
TS3
TS4
TS5
TS6
TS7
QH1
QH2
QH3
QH4
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Small river
Small river
Downstream of river
Upstream of river
Coastal area (harbor),
Downstream of river
Upstream of river
Coastal area (beach)
Upstream of tidal flat
Coastal area (tidal flat)
Coastal area (beach)
Lake
Coastal area (beach)
Small river
Small river
Small river
Coastal area (beach)
Small river
Upstream of river
Midstream of river
Downstream of river
Large river
Coastal area (tidal flat)
Midstream of river
Downstream of river
Coastal area (beach)
Coastal area (beach)
Small river
Coastal area (beach)
Downstream of river
Coastal area (tidal flat)
Downstream of river
Upstream of river
Downstream of river
Midstream of river
The MS temperature of source, quadrode and transfer line was 230, 150 and 300 ° C, respectively. Mass spectra were acquired in the electron ionization (EI) mode with an electron multiplier voltage of 906 eV.
Before quantification, the instrument was tuned daily based on the mass peaks of decafluorotriphenylphosphine (DFTPP).
123
PAHs in samples were identified by both the retention time and the abundance of quantification and confirmation ions with respect to PAHs standards
(Supelco, USA). Standards of 16 US EPA priority
PAHs [naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorine (Fl), phenanthrene (Phe), anthracene (An), fluoranthene (Flu), pyrene (Pyr),
Environ Geochem Health benzo[a]anthracene (BaA), chrysene (Chr), benzo[b] fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (Inp), dibenz[a,h]anthracene (DBA), and benzo[ghi]perylene (BgP)] were mixed in a solution of 200 mg/ml of each PAHs. A surrogate standard of phenanthrened
10 purchased from Supelco (Bellefonte, PA, USA) was added to the standard solution of 200 mg/ml.
Automated library searching was performed using the
National Institute of Standards and Technology (NIST)
Mass Spectral Database. Quantification was accomplished using a five-point external calibration curve for each of the 16 individual PAHs. Method limit of determination (LOD) ranged from 1.7 to 4.9 ng/g dry weight with those of the individual PAHs (Table
All the results are expressed on a dry weight basis.
Sediment pH was measured using a pH meter placed in a suspension of 10 g of air-dried sediment in
25 ml of deionized water. Total organic carbon (TOC) was quantified using a Universal CHNOS Elemental
Analyzer (ElementarVario EL III, Hanau, Germany).
Quality assurance and quality control
Laboratory quality control procedures included analyses of method blanks (solvent), spiked blanks (standards spiked into solvent) and matrix spikes. The analysis of matrix spikes and samples was performed in duplicate. Instrument stability and response were checked by injecting NIST standard solutions (DFTPP) periodically. The instrument was calibrated daily, and the relative percentage differences between the
Table 2 Characteristics and concentrations of 16 measured PAH in sediments (ng/g dw)
PAHs Rings LOD e
Average Min Max SD Median DR f
(%)
Nap
Acy
Ace
Fl
Phe
An
Flu
Pyr
BaA
Chr
BbF
BkF
BaP
Inp
DBA
BgP
P
16PAHs a
P
2–3-ring PAHs b
P
4–6-ring PAHs c
P
PAHcars d
2
3
3
3
3
3
4
4
4
4
5
5
5
6
5
6
1.8
2.2
1.8
1.7
2.2
2.9
3.7
3.1
3.6
3.4
2.6
4.9
3.9
4.7
3.5
2.7
10.3
6.3
9.4
13.2
52.8
10.8
47.1
42.2
37.9
33.0
80.7
11.6
34.0
49.6
2.1
31.2
472.0
102.6
369.4
248.8
0.0
0.0
0.0
3.5
6.2
1.0
7.3
0.9
6.0
0.7
3.3
1.0
5.8
8.7
0.8
4.2
52.3
4.4
47.9
35.7
69.3
104.5
46.9
58.6
188.6
52.4
202.5
163.7
175.9
140.0
365.9
64.1
161.6
218.2
8.3
128.0
1,870.6
335.8
1,552.3
1,096.9
15.6
17.4
10.8
13.7
41.1
12.3
51.1
40.3
43.7
38.2
104.2
16.7
36.8
57.8
1.8
34.3
483.4
87.4
411.3
294.4
f c a
Sum concentration of 16 PAH compounds b
Sum concentration of 6 low-molecular-weight PAH compounds (weight Nap, Ace, Acy, Fl, Phe and An)
Sum concentration of 9 low-molecular-weight PAH compounds (Pyr, BaA, Chr, BbF, BkF, BaP, Inp, DBA and BgP) e d
Sum concentration of 7 carcinogenic PAH compounds (Flu, BaA, BbF, BkF, BaP, Inp and DBA)
Limit of determination for each of the 16 individual PAHs
Detectable ratio (Detectable ratio = the number above the detection limit of each PAH individuals *100%/35)
5.0
19.5
28.7
1.4
17.8
329.7
91.7
219.8
142.9
3.6
2.9
5.8
8.4
47.6
5.8
27.2
33.0
22.2
19.4
34.6
100
100
100
100
100
100
100
100
100
100
100
100
100
86
94
94
123
five-point calibration and the daily calibrations were
\ 20% for all of the target analyses.
Statistical analyses
SPSS 17 and SigmaPlot
Ò
(Karnataka, India) 11 for
Windows were employed for statistical analysis.
Correlation analysis was used to explore relationships between PAHs and TOC. Principal component analysis (PCA) was used to examine the pattern of relative concentrations of PAHs. PCA converted the contribution of variables into two or three principal components (PCs) and facilitated identifying possible sources. The PCA component matrix was rotated using the varimax method to analyze relationships between the 16 PAHs. The detectable ratio (DR) of each PAHs was calculated as the number of sample above LOD divided by the total sample.
Results and discussion
Concentrations of PAHs in sediment
PAHs,
P
16PAHs) and concentrations of individual
PAHs in 35 sediment samples along CEANBYS,
China, are presented (Table
were less than the limits of detection were assigned a value of zero for calculation of the mean. Except for
Nap. Acy and Ace, the detectable ratios (DR) were all
100. The relatively large DR of PAHs in the sediment indicated the ubiquity of PAHs .
Concentrations of 16PAHs varied among sediment from 52.3 to 1,870.6 ng/g dw, with an average samples, concentrations of
P
16PAHs were less than
400 ng/g dw. The location with the greatest PAH concentration was TS1 in the Dou River at Tangshan.
Based on interviews with local residents, there are small factories along the river, from which waste water was discharged into the river without treatment.
where
P
16PAHs concentrations were greater than
1,000 ng/g dw. These were located at Dalian, Jinzhou and Dandong. At these locations, there were drainages from factories and city along the river that could be the sources of PAHs at these locations.
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Environ Geochem Health
Concentrations of the 7 carcinogenic PAHs (Flu,
BaA, BbF, BkF, BaP, Inp and DBA) ranged from 35.7
to 1,096.9 ng/g dw with an average of 248.8 ng/g dw.
concentration of
P
16PAHs. Generally, high-molecular-weight PAHs with four to six rings have higher toxicity than those low-molecular-weight PAHs with two or three rings. The median of concentration of the sum of high-molecular-weight PAHs ( R PAH4-6) was approximately fivefold greater than the sum of lowmolecular-weight PAHs ( R PAH2-3). This result is suggestive of greater potential for adverse effects of the PAHs to aquatic organisms in sediment along
CEANBYS.
Concentrations of 16 individual PAHs were correlated (Spearman, a = 0.01) (Table
sistent with PAHs originating from similar sources, and the sources were located in close proximity to the sampling locations (Chung et al.
). BaP can be used as a marker for some combustion-derived PAHs
(Magi et al.
2002 ). A significant correlation between
Bap and 16PAHs ( r
2
= 0.74, a \ 0.01) is consistent with combustion being the primary source of sediment PAHs in this area. Organic matter, which can influence chemical and biological behaviors of
PAHs through sorption/desorption and/or biodegradation, is considered to be a significant factor in determining accumulation of PAHs in sediments.
The positive correlation between PAHs and TOC
( r
2
= 0.41, a \ 0.01) is consistent with the PAHs being associated with organic carbon in sediment along CEANBYS.
The observed differences in concentrations of
PAHs in sediments along CEANBYS were related to differences in pollutants discharged as well as other human activities. PAH contents in sediment (Fig.
) were greatest at Jinzhou was 816.5 ng/g dw, followed tions of
P
16PAHs were approximately 600 ng/g dw.
The least concentration was observed at Qinhuangdao
(161.1 ng/g dw). The traditionally industrialized city of Liaoning, with more than 3 million people and 200 factories, is on the Jinzhou River, into which millions of tons of industrial wastewater is discharged every year. Alternatively, Qinhuangdao is a well-known tourist city where the environment is maintained by strictly enforced environmental controls, and some factories have been closed down and others have been upgraded to release less to the environment.
Environ Geochem Health
123
Fig. 2 Regional differences between concentrations of PAHs in the sediments
The concentrations of
P
16PAHs observed in this study were compared with concentrations reported of
P
16PAHs measured in this study were less than those reported for Dalian Bay (2,292 ng/g dw) (Liu et al.
), coastal Qinhuangdao (1,081.9 ng/g dw)
(Liu et al.
) and the Bohai and Huanghai Seas
(877.2 ng/g dw) (Ma et al.
16PAHs observed in this study were greater than those reported for the Liao (285.5 ng/g, dw) (Yang et al.
2007 ) and Daliao (287.3 ng/g dw) Rivers (Guo
et al.
2007 ) but similar to those for the Yalujiang
(68–1,500 ng/g dw) (Wu et al.
(6.7–1,585.7 ng/g dw)Rivers (Bai et al.
). Concentrations of 16PAHs measured in sediments during this study were greater than those for Baiyangdian Lake (101.3–322.8 ng/g dw) (Hu et al.
similar to those for Deep Bay, South China
(353.8
± trations of
128.1 ng/g dw) (Qiu et al.
). Concen-
16PAHs were less than those for the
Pearl River Estuary (1,434–10,811 ng/g dw) (Mai et al.
), Taihu Lake (1,207–4,754 ng/g dw) (Qiao et al.
) and the Lanzhou Reach of the Yellow
River (1,414 ng/g dw) (Xu et al.
the reach near Tianjin (1.1
9 10
6 ng/g dw) (Shi et al.
).
average concentration of
P
16PAHs in sediment was significantly less than those reported for the Detroit
River, Michigan, in America ( [ 1,000 ng/g dw) (Kannan et al.
2001 ) and for Osaka Castle Reservoir in Japan
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Environ Geochem Health
(66,700 ng/g dw) (Moriwakia et al.
tions of 16PAHs were greater than those in Ulsan Bay
(292 ng/g dw) (Khim et al.
) and Yeongil Bay
(309 ng/g dw) (Koh et al.
concentrations of PAHs in sediment along CEANBYS were less than those in other areas to which they were compared.
Relative proportions of PAH components and possible sources
The relative proportions of
P
16PAHs contributed by individual PAHs in sediments of CEANBYS were investigated to determine possible sources (Fig.
P
16PAHs, followed by Phe, Inp, Flu and Pyr, the
P
16PAHs in sediments. The proportions of PAHs with different numbers of rings were also investigated
(Fig.
.). The relative proportions of concentrations of
PAHs with different numbers of rings varied among sediments along the CEANBYS. The composition of PAHs followed a gradient of 4-ring [ 5-ring [
3-ring [ 6-ring [ 2-ring, and the higher-molecularfor 78% of the
P
16PAHs in sediments. This result was consistent with typical PAHs compositions observed in sediments from other polluted areas
(Khim et al.
; Kannan et al.
) and was similar to the pattern of relative concentrations of individual PAHs in sediments of the Daliao River
(Guo et al.
2007 ). The higher-molecular-weight PAHs
(4–6 rings) are less prone to degrade and are also more likely to be carcinogenic. This suggests that they would be more likely to be the cause of ecological risk in this region. As the traditional industrial base of
China, Liaoning Province has been industrialized longer than some other areas of China. Thus, there has been a longer period for accumulation of PAHs in the sediments of this region. PAHs are semi-volatile organics, with volatility being inversely proportional to molecular weight and the higher-molecular-mass
PAHs also have larger K ow
; thus, these larger PAHs tend to be adsorbed to suspended particles and be deposited in sediments (Greenfield and Davis
Molecular indices and statistics based on the ratios of individual PAHs concentrations in sediments have been used to distinguish PAHs derived from pyrogenic processes such as fossil fuel combustion and burning
Environ Geochem Health
Fig. 3 Histogram of concentrations of PAHs in sediments vegetation or from those released in petroleum from oil spills. The ratio of BaA/(BaA ?
Chr) can be used to distinguish between predominant sources of PAHs between petroleum hydrocarbons and pyrolysis of fuels. The ratio of Flu/(Pyr ?
Flu), along with the application of PCA, can be used to further distinguish between types of fuels (Sofowote et al.
Except for one sample from Panjin (PJ1), the BaA/
(BaA ?
Chr) ratios were all greater than 0.35, and the Flu/(Flu ?
Pyr) ratios were all greater than 0.4
(Fig.
). These results are consistent with combustion being the primary sources of PAHs in the sediment.
Among the locations with Flu/(Flu ?
Pyr) values greater than 0.4, about half of the ratios were greater than 0.5, which is consistent with liquid fossil fuel, and combustion of grass, wood, or coal being the primary sources of PAHs in this area.
The first two components (PCs) of the PCA had initial eigenvalues greater than 1.0 and together explained 72.0% and 11.3% of the total variance, respectively. After orthogonal rotation, based on the correlation between principle component 1 (PC1) and the higher-molecular-mass PAHs (4–6 rings, BbF,
BaA, Inp, Flu, BkF, BaP, Chr, Pyr, An) and between
PC2 and the lower-molecular-mass PAHs (2–3 rings,
Acy, Ace, Fl), it was determined that PC1 consisted of loadings primarily from the larger PAHs, while PC2 represented variance components contributed by the smaller PAHs (Fig.
The higher-molecular-weight PAHs (Chr, BbF,
Inp, BaP, Flu, BaA, Pyr, BkF,BgP, etc.) are typically
Fig. 4 Plots of PAH index pair ratios for source identification in the sediments
Fig. 5 Principal component analysis for PAH in sediment
123
released during combustion of coal, natural gas and straw stalk, and vehicle exhaust of gasoline and diesel
(Mastral and Callen
). PC1 is related to highermolecular-mass PAHs discriminated among samples based on variance components associated with combustion of coal, wood materials and emission of diesel oil as well as gasoline engines and that these were the primary sources of PAHs in the region. The second principal component (PC2), which represents the more volatile lower-molecular-mass PAHs in sediments, is related to the contribution of petroleum products. This area is one of the important petroleum development base in China. The result is consistent with the conclusion that oil exploitation has contributed to the
PAHs in sediment.
Ecological risk of PAHs in sediments
Due to the complex nature of sediments, it is often difficult to determine the potential effects of pollutants including PAHs in sediments. In China, there is no environmental standard established for PAHs in riverine or marine sediments. Therefore, the United
States numerical sediment quality guidelines (SQGs) were used to evaluate the environmental risks posed by PAHs in sediments of the Bohai Sea and Yellow
Sea to benthic invertebrates (MacDonald et al.
;
Liu et al.
). While these published values may not accurately represent actual effects, because they are applied in other jurisdictions, they were applied here as a reference values to which to compare. The effects range low (ERL, adverse effects at the 10% of tests in a
Biological Effects Data Base) and the effects range median (ERM, adverse effects at the 50% of the tests) have been used to assess the aquatic sediment with a ranking of lesser to greater impacts (Long et al.
;
MacDonald et al.
2000 ). ERL values indicated possi-
ble adverse biological effects on aquatic organisms, while ERM values suggested a great possibility of posing detrimental biological effects on aquatic organisms (Long et al.
Concentrations of
16PAHs in sediments at all locations were less than the ERL value of 4,000 n/ g dw. Concentrations of individual PAHs in sediments at all locations did not exceed the ERM, but at some locations, there was one constituent that might occasionally exceeded the ERL and might pose biological impairment (Table
concentrations of Acy, Ace and Fl were 104.5, 46.9
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Environ Geochem Health
Table 4 Standard pollution criteria of PAH concentrations for sediment (ng/g dw)
Compound Guidelines This study
Average Max Effects range low
(ERL)
Effects range median
(ERM)
An
Flu
Pyr
BaA
Chr
BbF
BkF
BaP
Nap
Acy
Ace
Fl
Phe
Inp
DBA
BgP
P
PAHs
384
NA
NA
430
853
600
665
261
160
44
16
19
240
NA
63.4
NA
4,000
2,100
640
500
540
1,500
1,100
5,100
2,600
1,600
2,800
NA
NA
1,600
NA
260
NA
44,792
10.8
47.1
42.2
37.9
33.0
80.7
11.6
34.0
10.3
6.3
9.4
13.2
52.8
49.6
2.1
31.2
472.0
69.3
104.5
46.9
58.6
188.6
52.4
202.5
163.7
175.9
140.0
365.9
64.1
161.6
218.2
8.3
128.0
1,870.6
and 58.6 ng/g dw, respectively, which exceeded the
ERL values of 44, 16 and 19 ng/g dw, respectively. If
PAH concentrations were less than the ERL, adverse effects on benthic invertebrates would be expected to seldom occur. However, if concentrations of PAHs were between the ERL and ERM, adverse effects would be expected to occur occasionally. If PAHs concentrations exceeded the ERM value, adverse effects would be expected to occur often. Based on the United States criteria, it can be concluded that current concentrations of PAHs in sediments of
CEANBYS would be unlikely to cause adverse effects. Adverse effects at the organism and/or ecosystem level can be used as an early warning indicator of potential human health impact. Continued research is necessary to establish the most appropriate indicators to use in describing coastal condition and the appropriate weighting factors for combining them for an overall assessment (EPA
).
In 2006, there were more than 8,000 industries along the areas of the northern Bohai Sea, and the value of their gross industrial output was 1.9
9 10
6 million Yuan, which accounted for 6.1% of national
Environ Geochem Health industrial output (China City Statistical Yearbook
). In the same year, the industrial wastewater discharge in this area amounted to 1.3 billion ton and the industrial dust amounted to 0.33 million ton
(China Environment Yearbook
). The industrial enterprises in this area rely on coal for energy.
Meanwhile, millions of gasoline and diesel are used as fuel. Therefore, to reduce PAH discharge in this region, it is necessary to improve the energy use efficiency and the energy structure.
Conclusions
Assessment of the status and trends of PAHs and potential sources are significant factors in the management and long-term conservation of marine ecosystems. Pollution and probable sources of PAHs in coastal and estuarine areas of the northern Bohai and
Yellow Seas were evaluated based on analysis of 35 surface sediments samples from marine and adjacent riverine/estuarine areas. Total concentrations of the 16
PAHs ranged from 52.3 to 1,870.6 ng/g dry weight, with an average of 472.0 ng/g dw. In comparison with other areas, the concentrations of PAHs in sediment were less. PAH accumulations in the sediments varied and reflected the regional differences in the pollutants discharge influenced by human activities. Sediment organic carbon content played an important role in controlling PAH concentrations in the sediments.
Molecular indices and principal component analysis
(PCA) reflected a mixed pattern of pyrolytic and petrogenic inputs of PAHs in the sediments in this area. Ecological risk posed by the accumulation of
PAHs in the coastal and estuarine areas of the northern
Bohai and Yellow Seas is relatively small.
Acknowledgments This study was supported by the National
Basic Research Program of China (‘‘973’’ Research Program) with Grant No.2007CB407307 and the Knowledge Innovation
Program of the Chinese Academy of Sciences with Grant
No.KZCX2-YW-420-5. Prof. Giesy’s participation in the project was supported by the Einstein Professor Program of the Chinese
Academy of Sciences.
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