Environ Monit Assess (2016) 188: 378
DOI 10.1007/s10661-016-5359-3
The relative abundance and seasonal distribution correspond
with the sources of polycyclic aromatic hydrocarbons (PAHs)
in the surface sediments of Chenab River, Pakistan
Imran Hussain & Jabir Hussain Syed & Atif Kamal & Mehreen Iqbal &
Syed-Ali-Mustjab-Akbar-Shah Eqani & Chui Wei Bong & Malik Mumtaz Taqi &
Thomas G. Reichenauer & Gan Zhang & Riffat Naseem Malik
Received: 17 November 2015 / Accepted: 9 May 2016 / Published online: 27 May 2016
# Springer International Publishing Switzerland 2016
Abstract Chenab River is one of the most important
rivers of Punjab Province (Pakistan) that receives huge
input of industrial effluents and municipal sewage from
major cities in the Central Punjab, Pakistan. The current
study was designed to evaluate the concentration levels
and associated ecological risks of USEPA priority polycyclic aromatic hydrocarbons (PAHs) in the surface
sediments of Chenab River. Sampling was performed
from eight (n = 24) sampling stations of Chenab River
and its tributaries. We observed a relatively high
abundance of ∑16PAHs during the summer season
(i.e. 554 ng g−1) versus that in the winter season (i.e.
361 ng g−1), with an overall abundance of two-, fiveand six-ring PAH congeners. Results also revealed that
the nitrate and phosphate contents in the sediments were
closely associated with low molecular weight (LMW)
and high molecular weight (HMW) PAHs, respectively.
Source apportionment results showed that the combustion of fossil fuels appears to be the key source of PAHs
in the study area. The risk quotient (RQ) values
Electronic supplementary material The online version of this
article (doi:10.1007/s10661-016-5359-3) contains supplementary
material, which is available to authorized users.
I. Hussain : A. Kamal
Department of Plant Sciences, Faculty of Biological Sciences,
Quaid-i-Azam University, Islamabad 45320, Pakistan
I. Hussain : T. G. Reichenauer
Department of Energy, AIT Austrian Institute of Technology
GmbH, Tulln, Austria
I. Hussain
Department of Molecular Systems Biology, Faculty of Life
Sciences, University of Vienna, Vienna, Austria
J. H. Syed (*) : G. Zhang
State Key Laboratory of Organic Geochemistry, Guangzhou
Institute of Geochemistry, Chinese Academy of Sciences,
Guangzhou 510640, China
e-mail: [email protected]
M. Iqbal : R. N. Malik (*)
Environmental Biology and Ecotoxicology Laboratory,
Department of Environmental Sciences, Faculty of Biological
Sciences, Quaid-i-Azam University, Islamabad 45320,
Pakistan
e-mail: [email protected]
S.<A.<M.<A.<S. Eqani
Public Health and Environment Division, Department of
Biosciences, COMSATS Institute of Information Technology
Chak Shehzad Park Road, Islamabad, Pakistan
C. W. Bong
Institute of Biological Sciences, Faculty of Science, University of
Malaya, 50603 Kuala Lumpur, Malaysia
378 Page 2 of 12
indicated that seven PAH congeners (i.e. phenanthrene,
anthracene, fluoranthene, pyrene, benzo(a)pyrene,
chrysene and benzo(a)anthracene) could pose serious
threats to the aquatic life of the riverine ecosystem in
Pakistan.
Keywords Polycyclic aromatic hydrocarbons (PAHs) .
Surface sediments . Source apportionment . Seasonal
distribution . Ecological risk assessment . Chenab River
Introduction
Polycyclic aromatic hydrocarbons (PAHs) are organic
contaminants of two or more fused benzene rings. Due
to their toxic, mutagenic and carcinogenic potential
(Zheng et al. 2014), PAHs have great environmental
concerns. The US Environmental Protection Agency
(USEPA) and European Environment Agency (EEA)
have defined 16 PAHs as priority pollutants. Some of
them were also listed as priority pollutants by the Chinese Government in the Environmental Quality Standard (Ma et al. 2014). Some of these PAHs have been
included in the list of substances of very high concern
(SVHC) by the European Chemicals Agency. PAHs are
listed individually on EPA’s priority chemical list due to
their persistence, bioaccumulative and carcinogenic nature (Park et al. 2011; Li et al. 2010; Kamal et al. 2014b).
PAHs might pose several human health risks such as
damage of red blood cells (RBCs), haemolytic anaemia
in children and toxic responses to the kidney and liver in
animals (Kamal et al. 2014a). Behind the fact, the 16
EPA priority PAHs have some natural sources like forest
fires and volcanic eruptions (Yang et al. 2010). Few
PAHs [especially naphthalene (Nap) and phenanthrene (Phe)] may be biologically produced in plants,
soils and sediments, which could have some influence on the distribution of PAHs in the riverine
ecosystem (Cabrerizo et al. 2011). They are mainly
originating from anthropogenic activities (Kamal
et al. 2014b). These anthropogenic sources can be
broadly classified as pyrogenic and petrogenic
C. W. Bong
Institute of Ocean and Earth Sciences (IOES), University of
Malaya, 50603 Kuala Lumpur, Malaysia
M. M. Taqi
NORMENT, University of Oslo, Oslo, Norway
Environ Monit Assess (2016) 188: 378
sources including combustion of biomass and fossil
fuel. Moreover, they can also come from chemical
industries such as oil refinery, diesel, gasoline, kerosene and chemical engineering processes (Kim et al.
2013; Cao et al. 2010).
Sediments are usually the ultimate sinks of PAHs and
other contaminants discharged into the environment.
They reflect the input from point and non-point sources
of contamination (Hahladakis et al. 2013; Pies et al.
2008). Properties, such as high toxicity, high stability,
high lipophilicity, electrochemical stability and adsorption to sediments, make PAHs a potentially dangerous
group of chemicals. The sediment becomes a long-term
repository and a steady indicator of environmental pollution (Martinez et al. 2004; Villar et al. 2006; Duke and
Albert 2007; Kumar et al. 2008; Nikolaou et al. 2009;
Hahladakis et al. 2013). Once PAH-enriched particles
accumulate in sediments, they may undergo a number of
changes caused by chemical, biological and physical
activities. As a result, the bound PAHs can be
remobilised from the sediment into the water phase
and tend to bioaccumulate in aquatic organisms (Kumar
et al. 2008).
Chenab River is one of the major river of Punjab
Province (Pakistan) and receives a huge input of
industrial effluents and municipal sewage from many
point and non-point sources of industrial cities including Faisalabad, Gujrat, Mandi Bahauddin, Jhang,
Chiniot, Multan, Hafizabad, Sargodha, Khanewal
and Muzaffargarh. To the best of our knowledge, a
few studies have been reported on persistent organic
pollutants (POPs) in different environmental compartments of Pakistan (Singh et al. 1995; Malik et al. 2011;
Syed et al. 2014; Bibi et al. 2015; Zahra et al. 2014; Aziz
et al. 2014). Few recent studies have also been conducted on monitoring of the Chenab River ecosystem and
its associated tributaries regarding heavy metals and
organochlorine pesticide pollution (Qadir and Malik
2011; Eqani et al. 2010; Malik et al. 2011; Syed et al.
2013; Mahmood and Malik 2014). Since no information is available on concentration levels and distribution of PAHs in the riverine ecosystem of Pakistan,
this study was designed (i) to evaluate the levels and
distribution of PAHs in the surface sediments, (ii) to
determine the spatio-temporal variations of PAHs in
the riverine sediments and (iii) to distinguish the
possible sources of PAHs using diagnostic ratios,
statistical techniques and assessment for the potential
ecological risks of benthic organisms.
Environ Monit Assess (2016) 188: 378
Page 3 of 12 378
Materials and methods
Sampling procedure and characterisation of samples
Study area
A total of 24 composite surface sediment samples
(n = 24 composites and 84 individuals) from the above
sampling sites were collected during two sampling seasons, summer and winter, in 2007. Surface sediments
(0–3 cm) were collected with the help of sterile stainless
steel grab samplers operated by hand line. From each
site, we collected three to four samples that were
homogenised and transferred into clean glass jars
capped with aluminium foil. The samples were freezedried, passed through a 2-mm sieve and stored for
further analysis. For each sample, a new steel grab was
used to avoid cross-contamination. Organic matter
(OM) contents of sediment samples were determined
by a Tyurin or wet oxidation method (Syed et al. 2013;
Walkley and Black 1934). The proportions of sand, silt
and clay were calculated using a Bouyoucos hydrometer
(Bouyoucos 1962). Sediment textural classes were determined on the basis of relative proportion of soil
particles using a textural triangle. Sediment quality parameters like pH, electrical conductivity (EC) and total
dissolved solids (TDSs) of sediment samples were determined using portable Hydrolab (Milwaukee, model
SM802). Other parameters including alkalinity (ALK),
sulphates (SO42−), phosphates (PO43−), chlorides (Cl−),
nitrate-nitrogen (NO3-N) and orthophosphates (SRP)
were measured in a laboratory under standard protocols
reported by the American Public Health Association
(APHA) (1998).
Chenab River is one of the largest and extensive rivers of
Pakistan, and it originated from India in Kullu and
Kandra districts of Himachal Pradesh Province. The total
stretch of the river is about 772 miles of which approximately 453 miles flows through Pakistan. Chenab River
has massive importance due to its flow and extensive
canal system that originates from this river. It passes
through most of the important agricultural areas like
Gujarat, Sialkot, Gujranwala, Jhang, Khanewal and Multan districts in Punjab Province. The present study area is
spatially located between 29° 72′ 1″–31° 17′ 1″ N and
71° 19′ 9″–72° 14′ 7″ E. A total of eight sampling sites
(SS-1–SS-8) were included in this study, and out of
which, six sites located on the main stretch of Chenab
River, River Ravi and River Jhelum (Fig. S1). Two
sites (SS-1 and SS-2) were situated upstream of River
Jhelum and Chenab River before the confluence point
(Trimmu Headworks) of both rivers (Farooq et al. 2011).
SS-1 and SS-2 were located on adjoining tributaries of
Chenab River, i.e. River Ravi and River Jhelum. SS-1
was located upstream of River Jhelum almost 15 km
from Trimmu Headworks, the converging point of Chenab River and River Jhelum. SS-2 and SS-3 were situated
on the Chenab River; SS-2 is located near Jhang City
which received huge amounts of industrial effluents and
urban wastes from surrounding areas. SS-3 was located
20 km downstream from Trimmu Headworks in Jhang
District and was largely influenced by the surrounding
agricultural activities and electric grid station near
Shorkot. SS-4 was located upstream of the Ravi River
in Khanewal District. This site is surrounded by urban
areas and receiving a huge load of pollutants from municipal waste and automobiles. River Ravi also receives
a huge load of pollutants while transverse through different industrial and urban areas, i.e. Lahore, Qasoor and
Faisalabad. Other sites (SS-5 and SS-6) were located in
the cotton belt of Khanewal District. Agricultural activities in these areas are the main source of pollution. The
last two sites (SS-7 and SS-8) were located on Sher Shah
Bridge, Multan, and Chund Bridge, Jhang, respectively.
SS-7 was dominated by tourist activities and rapid urbanisation around the river. An electric grid station and
Pak-Arab Refinery (PARCO) is also present at this site.
SS-8 was a site which received industrial effluents from
Faisalabad City.
Sample preparation (extraction and clean-up)
Briefly, each sample (~20 g) was extracted using a
soxhlet extraction system with dichloromethane
(DCM), for 24 h. Prior to extraction, the samples were
spiked with known concentrations of surrogate standard,
i.e. naphthalene-d8, acenaphthene-d10, phenanthrened10, chrysene-d12 and perylene-d12 (AccuStandard
Chem. Co.), to evaluate the method performance and
matrix effect (Liu et al. 2007). The sulphur impurities
were removed during extraction with the addition of
activated copper to the collecting flasks. Extracts were
concentrated and solvent-exchanged into n-hexane,
which was further purified using silica/alumina column
(8 mm I.D.) packed with neutral alumina (10 cm, 3 %
deactivated), neutral silica (10 cm, 3 % deactivated) and
1 cm anhydrous sodium sulphate on the top to trap
moisture contents. Alumina, silica gel and anhydrous
378 Page 4 of 12
sulphate were pre-extracted to remove all the impurities
and then baked for 12 h at 250, 180 and 450 °C, respectively. The column was pre-washed with n-hexane and
eluted with 50 ml of dichloromethane/hexane to collect
the PAH fraction. The fraction was solvent-exchanged to
n-hexane and concentrated to 100 μl under a gentle nitrogen stream. A known quantity of hexamethylbenzene
(Aldrich Chemical, Gillingham, Dorset, USA) was used
as internal standard before GC-MS analysis.
Chromatographic analysis
Extracts were analysed using a Hewlett-Packard 5890
gas chromatograph equipped with a mass-selective detector which operated in electron impact mode (70 eV).
The following 16 EPA PAHs were analysed: Nap, acenaphthylene (Acy), fluorene (Flu), Phe, anthracene (Ant),
fluoranthene (Flua), pyrene (Pyr), benzo(a)anthracene
(BaA), chrysene (Chr), benzo(b)fluoranthene (BbF),
benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP),
indeno(1,2,3-c,d)pyrene (Ind), benzo(ghi)perylene
(BghiP), benzo(k)fluoranthene (BkF) and coronene (Coro). Separation of PAHs was carried out by a HP-5ms
column (30 mm × 0.25 mm × 0.25 μm). The injector
temperature used was 280 °C, and the ion source temperature was 180 °C. GC temperature program was initially maintained at 60 °C for 2 min, increased to 290 °C
at the rate of 3 °C min−1 and held for 30 min. Helium was
used as a carrier gas, at a constant flow rate of
1.5 ml min−1. A 1-ml sample was injected in split less
mode. Data acquisition and processing was controlled by
HP ChemStation software. Chromatographic peaks of
samples were identified by mass spectra and by comparison with standards.
Quality control and quality assurance (QC/QA)
During all analytical procedures, strict quality control
procedures were followed, including the analysis of
blanks and spiked samples, and the method blanks
(solvent), duplicate samples and spiked blanks (standards spiked into solvent) were run with each batch of
three samples. The surrogate standards (naphthalene-d8,
acenaphthene-d10, phenanthrene-d10, chrysene-d12
and perylene-d12) were added to all the samples, and
the recoveries were calculated as follows: 88 ± 10, 75
± 4, 85 ± 6, 77 ± 5 and 86 ± 8 %, respectively. The reported concentrations of PAHs were blank corrected. All
the instruments were calibrated on a daily basis and
Environ Monit Assess (2016) 188: 378
were strictly observed for cross-contaminations. DCM,
n-hexane, acetone and methanol were purchased from
Dikma Co. (Beijing, China). All the organic solvents
were re-distilled in a full-glass distilling appliance.
Statistical analysis
All the results were compiled to from a multi-elemental
database using Excel software. The data was tested for
normality using a K-S test and was presented as mean,
standard deviation, minimum and maximum of PAHs,
and physico-chemical parameters of the surface water
samples of all sites were calculated for 16 PAHs and 11
physico-chemical variables. Hierarchical aligned cluster
analysis (HACA) was performed using Euclidean distance as a distance matrix and complete linkage as a
linkage method to take out information regarding spatial
similarities/dissimilarities between sampling sites based
on the PAH levels in the surface sediments of Chenab
River. Principal component analysis based on the
factor analysis (FA/PCA) was employed for the source
identification of PAHs. Temporal FA/PCA was
employed for the summer and winter sampling seasons.
All these statistical analyses were performed using statistical software package (Statistica) and Statistical
Package for the Social Sciences (IBM SPSS Statistics
for Windows, version 20.0. Armonk, NY; IBM Corp.).
Results and discussion
PAH concentrations in Chenab River
Overall concentration levels of individual and
∑16PAHs in the surface sediments of Chenab River
are summarised in Table S1. The PAH profiles were
dominated by Phe (68.4 ± 39.6 ng g−1) and Nap (67.0
± 35.3 ng g−1). The dominance of Phe is an important
aspect as it is a widely occurring PAH congener in the
sediments (Ke et al. 2005), and in addition, the Nap was
also found in relatively high concentrations in the sediments collected from South China Sea (Yang 2000).
The dominance of these congeners showed that they
could have arisen from source-emitting low molecular
weight PAHs. The results indicated that low molecular
weight (LMW) PAHs having three or fewer rings were
abundant in the sediments as compared to the high
molecular weight (HMW) PAHs having four or more
rings. The patterns of PAHs among all the studied
Environ Monit Assess (2016) 188: 378
sampling sites (combined and separate in each season)
were bearing the highest concentration of three-ring
PAHs followed by four-ring PAHs > two-ring PAHs >
five-ring PAHs > six-ring PAHs (Fig. S2; Fig. S3).
Some of the individual and overview of season variation
showed higher PAH levels in the summer season (evidenced from the sum of 16 PAHs (∑16PAHs) which
ranged between 181 and 487 ng g−1), with an average of
361 ng g−1 in the winter season versus 162–554 ng g−1
(average of 482 ng g−1) in the summer season (Fig. S4).
In fact, the relative abundance of PAHs in the sediments,
their fate and distributions are largely governed by
physico-chemical properties of sediments (pH, EC, organic matter and clay contents) and the source of PAH
(Zhang et al. 2004a, b). Sedimentary OM largely influences the process of adsorption, binding, degradation
and bioaccumulation of PAHs (Yang et al. 2010). In
addition, the anthropogenic activities and climatic conditions (such as temperature, solar radiation and rainfall)
greatly influence the seasonal variability of PAH concentrations in the environment (Della et al. 2003). The
results of the present study showed that the spatial
variability of PAHs is site and season specific. In our
opinion, the low flow rate of Chenab River, the increased bank stability, low erosion and increased water
turbidity could have been facilitating the sedimentation
in Chenab River. In particular, the high temperature
expedites the degradability of PAHs in sediments
(Deng et al. 2006).
As a matter of fact, the selected study area in this
study routinely receives a huge rainfall between the
months of July and August (monsoon season) per
annum. This heavy input of rainfall dilutes the contaminants in aquatic ecosystem and washes away most of
the contaminants or causes dispersion of such pollutants. Since a low sedimentation (a result of high flow
rate, reduced bank stability and high erosion) could
increase water turbidity, which is a reason behind the
lower and/or comparable concentration levels of
PAHs at most of the sampling sites (i.e. SS-3, SS-4,
SS-5, SS-6 and SS-8) in summer than the winter
season (Fig. S4). In contrast, high summer concentrations in the samples collected from SS-1 and SS-2
might be due to the industrial and agricultural activities near Jhang City while SS-7 was dominated by
tourist activities and rapid urbanisation around the
river. Overall, concentration levels of measured
∑PAHs in this study were found comparatively
higher in summer than the winter season.
Page 5 of 12 378
Similar trends (i.e. higher concentration of PAHs in
winter than in summer) have been reported in several
previous studies from other regions of the world including Guangzhou (31 ng g−1 in winter and 20 ng g−1 in
summer), Taichung (56 ng g−1 in winter and 20 ng g−1 in
summer), Shizuoka (41 ng g−1 in winter and 19 ng g−1 in
summer), Hong Kong (310 ng g−1 in winter and
90 ng g−1 in summer) and Beijing (152 ng g−1 in winter
and 118 ng g−1 in summer) reports. Similarly, this seasonal behaviour of PAHs was also studied in other
regions as well, including Zonguldak (142 in winter
and 6 in summer), Delhi (1157 ng g−1 in winter and
624 in summer) and Kaohsiung which had high concentrations of PAH in winter (183 ng g −1 ) and
95 ng g−1 in summer (Fang et al. 2007; Tian et al.
2009; Kume et al. 2007; Della et al. 2003; Sharma
et al. 2007; Chen et al. 2008; Tan et al. 2006; Wang
et al. 2008) (Table S2).
Cluster analysis of PAH variation among sites
The CA grouped the PAH variability into contaminated
three distinct sites (Fig. 1). The first group comprised of
sites SS-1, SS-3 and SS-8; in these sites, we observed
substantial PAH concentrations ranging between 253
and 600 ng g−1 (average of 424 ng g−1). In general, all
these sites belong to the agricultural cotton belt, where
four-, five- and six-ring PAH congeners were the most
abundant, with negligible seasonal influence (Supplementary files). However, the seasonal variations were
more influential on the edifice factors including EC,
TDS and alkalinity values (generally high in summer).
In the second group, a cluster of SS-2 and SS-7 was
observed which are mainly urban areas, with a high
concentration of PAHs. The total PAHs in these areas
ranged between 621 and 775 ng g−1 (average of
700 ng g−1), which were higher than those in the cotton
belt region (discussed earlier). This cluster represents a
massive influence of urban anthropogenic activities and
a different land use pattern. Moreover, the concentration
of chlorides, phosphates and clay contents was also high
in these sites, especially during the summer season.
Additionally, the pH and chloride, nitrate, clay and silt
contents were also high in the winter season. In comparison to the groups specified by the cluster analysis,
the six-ring PAHs were present in abundant form with
mean concentrations of 58 ng g−1 (Figs. 2 and 3).
The third group consisted of SS-4, SS-6 and SS-5,
which are sub-urban regions, while the PAH
378 Page 6 of 12
Environ Monit Assess (2016) 188: 378
Fig. 1 Hierarchical dendrogram
of sampling sites (based on
Ward’s linkage method) and
squared Euclidean distance
matrix
concentrations in these sites ranged from 527 to
643 ng g−1, with an average of 610 ng g−1. We
observed the high concentrations of three-ring PAHs in
these sites. A different profile of PAH congeners was
observed, i.e. three-ring PAHs > four-ring PAHs > tworing PAHs > six-ring PAHs > five-ring PAHs in summer,
while in winter, the majority of three-ring PAHs were
observed followed by > two-ring PAHs > four-ring
PAHs > five-ring PAHs > six-ring PAHs. These suburban sites had a specific load of pollutions, where
nitrates, organic matter, silt and sand showed predominance in the summer season, whereas the values of EC,
TDS, alkalinity, phosphates and organic matter were
more influenced by the winter season.
Composition and source apportionment of PAHs
We performed the source apportionment to gain basic
information about fate, behaviour and translocation of
PAHs since; to this purpose, PCA and the molecular
diagnostic ratios were applied. The ratios used included
the HMW/LMW, Phe/Ant, Flua/Pyr, Chr/BaA, Pyr/BaP,
Ant/Ant+PhA (Ant/178), Fla/Fla+Pyr, BaA/BaA+Chr
(BaA/228), Ind/Ind+BghiP and COMB/∑EPA PAHs
(Yunker et al. 1996, 2002). The Ant/178, Fla/Fla+Pyr,
BaA/228 and Ind/Ind+BghiP ratios <0.1, 0.4 and 0.2
suggested a combustion origin of PAH activities, while
the ratios >0.1, 0.4, 0.2 and 0.35 point to pyrolytic
sources, respectively (Yunker et al. 2002; Liu et al.
Fig. 2 Concentrations of individual PAHs and physiochemical parameters of surface sediments based on clustering of sampling sites
Environ Monit Assess (2016) 188: 378
Page 7 of 12 378
Fig. 3 Spatial and seasonal distribution of total PAHs on different sampling locations along the river stretch
2008). In addition, the ratio of Phe/Ant, Chr/BaA and
Fla/Pyr <10 and 1 respectively indicated a pyrolytic
origin of PAHs; likewise, the Phe/Ant ratios >10 and 1
suggest a petrogenic origin of PAHs (Soclo et al. 2000).
In the summer season, the ratios of Ant/178, Fla/Fla+
Pyr, BaA/228, Ind/Ind+BghiP, Phe/Ant, Fla/Pyr, Chr/
BaA and Pyr/BaP were 0.08, 0.35, 0.02, 0.31, 16.16,
0.58, 1.59 and 42.7, respectively. These ratios indicated
a petrogenic origin of PAHs in summer, probably from
the heavy traffic exhaust, influenced by high ambient
temperature. The average values of diagnostic ratios in
the winter season were 0.28, 0.31, 0.15, 8.87, 0.40, 1.13
and 99.21, respectively, indicating the pyrolytic PAH
sources, which were also supported by the Phe/Ant
(Table 1) and the cross plot of Ind/Ind+BghiP (Fig. 4).
The factor score matrix of PCA explained (Table S3)
a total of 89.22 % variance of the data and grouped the
variables into five new factors. Factor 1 explained the
highest percentage of the total variance (29. 96 %), with
factor loadings of BaA (0.88), Chr (0.93), BkF (0.71),
BaP (0.82), Ind (0.90) and DghiA (0.92). The factor
grouped major HMW PAHs, associated with pyrolytic
and biogenic sources and a mixture of petroleum and
coal combustion sources. The second factor accounted
for 17.82 % of the total variance. PC2 has high factor
loadings like Nap (0.82), Ace (0.71) and nitrates (0.78).
This factor grouped the LMW PAHs with nitrates,
which supports their co-origin from the biogenic sources
(e.g. combustion of biomass fuels). The third factor
(explains 12.16 % of the total variance) had a high
loading of clay (−0.71) and EC (−0.91); in particular,
the loading of clay suggested that the clay contents
mainly influenced the EC and TDS in these sediments.
Factor 4 (10.81 % of the total variance) appeared with a
high loading of silt (0.92) and sand (−0.84). This factor
only explains the inverse relationship of sand and silt
regarding PAH deposition on sediments. Factor 5
accounted for 6.18 % of the total variance and has a
378 Page 8 of 12
Environ Monit Assess (2016) 188: 378
Table 1 Diagnostic ratios and physico-chemical parameters of surface sediments collected from Chenab River, Pakistan, during summer
and winter seasons
Parameters
Summer season
P valuesa
Winter season
Mean ± SD
Min-Max
Mean ± SD
Min-Max
Ant/178
0.08 ± 0.01
0.01–0.41
0.15 ± 0.06
0.02–0.37
<0.01
BaA/228
0.02 ± 0.01
0.02–0.09
0.021 ± 0.04
0.02–0.07
ns
Chr/BaA
1.59 ± 0.61
0.15–0.6
1.13 ± 0.9
0.64–2.2
0.05
∑COMBb/∑PAHs
0.32 ± 0.11
0.53–3.79
0.26 ± 0.11
0.15–0.58
ns
Diagnostic ratios
Fla/Fla+Pyr
0.35 ± 0.21
0.03–0.5
0.28 ± 0.13
0.07–0.38
ns
Fl/Pyr
0.58 ± 0.05
0.03–1
0.4 ± 0.2
0.07–0.6
0.053
HMW/LMW PAHs
0.61 ± 0.06
0.17–1.7
0.42 ± 0.09
0.17–1.4
0.04
Ind/Ind+BghiP
0.31 ± 0.2
0.04–0.5
0.15 ± 0.08
0.03–0.37
0.039
Phe/Ant
16.16 ± 0.65
1–31.5
8.87 ± 1
1.2–27.5
0.042
Pyr/BaP
42.7 ± 0.2
1–281.5
99.2 ± 12.6
6–334
0.03
ns
Physiochemical parameters of soil/sediments
pH
8.48 ± 0.3
7.13–9
7.9 ± 0.83
7–8.9
EC
66.2 ± 33
10–190
122 ± 71.3
20–210
0.029
TDS
41.2 ± 29
0.04–120
77.5 ± 44
10–140
0.049
Alkalinity
0.4 ± 0.1
0.24–0.54
0.94 ± 0.27
0.5–1.3
0.05
Chloride
0.58 ± 0.2
0.37–0.9
0.73 ± 0.08
0.63–0.8
ns
Phosphate
0.04 ± 0.01
0.03–0.05
0.03 ± 0.01
0.02–0.06
ns
Nitrates
0.31 ± 0.23
0.12–0.8
0.24 ± 0.15
0.14–0.6
ns
OM
0.74 ± 0.48
0.17–1.37
2.65 ± 1.7
0.26–4.4
<0.01
8.6 ± 5.76
2.7–20
7.2 ± 4.9
0.1–16.6
0.048
Textural classes
Clay
Silt
8.31 ± 7.92
0.5–19.5
7.92 ± 5
0.8–17.7
ns
Sand
82.6 ± 11.61
67–96.5
85 ± 7
71.2–95
ns
P value = probability values; α is set at 0.05
HMW high molecular weight, LMW low molecular weight, EC electric conductivity, OM organic matter, TDS total dissolved solid, ns nonsignificant
a
Independent sample t test-based analysis
b
Sum of combustion origin of PAHs
high loading of Ant (0.95), Fl (0.83) and Pyr (0.93)
contents that were related to the phosphate (0.72) contents of the sediments; this could be an indicator of coemission of these components from biogenic sources.
Estimates of ecological risk
The ecological risk from PAH contamination can be
categorised into low, moderate, high and very high,
when ∑PAHs range between 0 and 100, between 100
and 1000, between 1000 and 5000 and greater than
5000 ng g−1, respectively (Agarwal et al. 2009).
Adopting this criteria, the evaluated risk in this study
(in both seasons) could be categorised as a moderate
pollution level (Zhang and Tao 2009). Ecological risk
assessment (ERA) using risk quotients (RQs) is used for
the evaluation of the undesirable impacts caused by the
environmental pollutants in an ecological system. For
evaluation of the ecosystem risk by PAHs in Chenab
River, risk quotients of negligible concentration
(RQs(NC)) and risk quotients of maximum permissible
concentration (RQs(MPC)) for individual PAHs and
∑PAHs were calculated and compared with their
reference quality values in the present study. In
Environ Monit Assess (2016) 188: 378
Page 9 of 12 378
Fig. 4 Cross-plot of the isomeric
ratios of Fla/(Pyr + Fla) vs. IndP/
(IndP + BghiP) in both summer
and winter seasons
Pakistan, no data regarding reference values exists for
organic contaminants, so the values reported by Kalf
et al. (1997) were used. The methodology for risk evaluation is detailed elsewhere (Cao et al. 2010). In principle, if both RQsNC and RQsMPC are >1 for individual
PAH, then the risk is high and immediate actions should
be taken. When RQsNC are >1 and RQsMPC are <1, then
the risk associated with PAH contamination is midline.
The risk classification for ∑PAHs is given in Table 2.
In this study, the calculated mean values of RQsNC
for Nap, Acy, Fla, Phe, Ant and Pyr in the sediment
samples were much higher than 1; however, the
RQsMPC of individual PAHs were less than 1, with the
highest value of RQsMPC for NAP (0.71), Fla (0.63) and
Pyr (0.52), indicating that aquatic biota could be considered under moderate risk posed by carcinogenic compounds (Table 2). The RQsNC and RQsMPC for total
PAHs showed low to moderate risks of toxicity to the
aquatic life of Chenab River. The results demand a more
detailed investigation in order to identify and control the
sources of Nap, Acy, Fla, Phe, Anta and Pyr pollution in
the riverine system of Chenab and to mitigate the toxicity risk to the aquatic organism in Chenab River.
Table 2 Mean values of RQsNC and RQsMPC of PAHs in the
sediments of Chenab River
PAHs
TEFsa NCsb MPCsb Mean
(ng/g)
RQsNCb RQMPCb
Ace
Acy
Ant
BaA
BaP
BbF
BghiP
BkF
Chr
DahA
Fla
Fl
Ind
Nap
Phe
Pyr
∑PAHs
0.001
0.001
0.001
0.1
1
0.1
0.01
0.1
0.01
1
0.001
0.01
0.1
0.001
0.001
0.001
–
29.42
35.09
22.93
1.69
0.30
3.67
0.28
0.49
0.07
0.17
62.57
1.25
0.17
70.82
20.81
52.27
1.80
The present study provides the first systematic data on
the distribution, fate and behaviour of PAHs in the
120
120
120
360
2700
360
7500
2400
10700
2700
120
2600
5900
140
510
120
32930
35.30
42.11
27.52
6.09
8.15
13.21
21.08
11.69
7.73
4.46
75.08
32.42
10.23
99.15
106.15
62.73
593.50
0.29
0.35
0.23
0.02
0.00
0.04
0.00
0.00
0.00
0.00
0.63
0.01
0.00
0.71
0.21
0.52
0.02
a
TEF for individual PAHs relative to BaP as reported by Nisbet
and LaGoy (1992)
Risk classification for individual PAHs: the value of 0.0 or ≥1 is
risk-free and moderate-risk RQsNC, respectively, while the value
of <1 and ≥1 is moderate- and high-risk RQsMPC, respectively. For
∑PAHs, low, moderate and high RQNC ∑PAH values are ≥1, <800
and ≥800, and <800 and ≥800, respectively. In the case of RQMPC
∑PAHs, low and moderate values are 0, while values ≥1 are
considered to be high risk
b
Concluding remarks
1.2
1.2
1.2
3.6
27
3.6
75
24
107
27
1.2
26
59
1.4
5.1
1.2
329.3
378 Page 10 of 12
surface sediments of Chenab River, Pakistan. The results highlighted that PAH contamination should be
considered as an important environmental issue due to
their mutagenic and carcinogenic effects. Source apportionment revealed that PAH emissions might be from
both industrial and agricultural sectors, so proper management practices should be done to overcome the
occurrence as well as transportation of PAHs in the
riverine ecosystem of Pakistan. According to a PAH
pattern, three clusters emerged that are corresponding
with the land use in the respective area. The contamination levels measured in the surface sediments highlight
the need to study the associated risks to the aquatic
ecosystem and, in particular, to the humans as well as
other animals.
Acknowledgments The authors are thankful to the Higher Education Commission, Pakistan, for the financial support and to the
Pakistan Wetland Program (PWP) for providing transport during
the study. The experimental work was conducted at the State Key
Laboratory of Organic Geochemistry Guangzhou (SKLOG), Chinese Academy of Sciences (CAS). We are also grateful to Dr.
Abdul Qadir, Raja Rizwan Ullah and Muhammad Nadeem for
their help during field sampling. SAMAS Eqani is thankful to Dr.
Li Jun, Dr. Promita and Dr. Yanlin Zhang for their help during
experimental work. JH Syed is highly thankful to the Chinese
Academy of Sciences (CAS) for PIFI (2015PE029) and NSFC
(41550110225) project.
References
Agarwal, T., Shridhar, V., & Ray, S. (2009). Pattern sources and
toxic potential of PAHs in the agricultural soils of Delhi,
India. Journal of Hazardous Material, 163, 1033–1039.
American Public Health Association (APHA). (1998). Standard
methods for the examination of water and wastewater (20th
ed.). Baltimore: United Book Press, Inc.
Aziz, F., Syed, J. H., Malik, R. N., Katsoyiannis, A., Mahmood,
A., Li, J., Zhang, G., & Jones, K. C. (2014). Occurrence of
polycyclic aromatic hydrocarbons in the Soan River,
Pakistan: Insights into distribution, composition, sources
and ecological risk assessment. Ecotoxicology and
Environmental Safety, 109, 77–84.
Bibi, M., Hashmi, M. Z., & Malik, R. N. (2015). Human exposure
to arsenic in groundwater from Lahore district, Pakistan.
Environmental Toxicology and Pharmacology, 39(1), 42–52.
Bouyoucos, G. J. (1962). Hydrometer method improved for making particle size analyses of soils. Agronomy Journal, 54,
464–465.
Cabrerizo, A., Dachs, J., Moeckel, C., Ojeda, M. J., Caballero, G.,
Barceló, D., & Jones, K. C. (2011). Ubiquitous net volatilization of polycyclic aromatic hydrocarbons from soils and
parameters influencing their soil− air partitioning.
Environmental Science & Technology, 45(11), 4740–4747.
Environ Monit Assess (2016) 188: 378
Cao, Z., Liu, J., Luan, Y., Li, Y., Ma, M., Xu, J., & Han, S. (2010).
Distribution and ecosystem risk assessment of polycyclic
aromatic hydrocarbons in the Luan River, China.
Ecotoxicology, 19, 827–837.
Chen, J., Wong, M. H., Wong, Y. S., & Tam, N. F. (2008). Multifactors on biodegradation kinetics of polycyclic aromatic
hydrocarbons (PAHs) by Sphingomonas sp. a bacterial strain
isolated from mangrove sediment. Marine Pollution Bulletin,
57(6), 695–702.
Della, W. M., Wong, Y. C., Choi, Y. Y., Lamaandpeter, C. H., &
Louie, K. K. (2003). Distribution of polycyclic aromatic
hydrocarbons in the atmosphere of Hong Kong. J Environ
Monit, 5, 989–996.
Deng, H., Peng, P., Huang, W., & Song, J. (2006). Distribution and
loadings of polycyclic aromatic hydrocarbons in the Xijiang
River in Guangdong, South China. Chemosphere, 64(8),
1401–1411.
Eqani, S. A. M. A. S., Malik, R. N., & Mohammad, A. (2010). The
level and distribution of selected organochlorine pesticides in
sediments from River Chenab, Pakistan. Environmental
Geochemistry and Health, 33(1), 33–47.
Fang, M. D., Hsieh, P. C., Ko, F. C., Baker, J. E., & Lee, C. L.
(2007). Sources and distribution of polycyclic aromatic hydrocarbons in the sediments of Kaoping river and submarine
canyon system, Taiwan. Marine Pollution Bulletin, 54(8),
1179–1189.
Farooq, S., Eqani, S. A. M. A. S., Malik, R. N., Katsoyiannis, A.,
Zhang, G., Zhang, Y., Li, J., Xiang, L., Jones, K. C., &
Shinwari, Z. K. (2011). Occurrence, finger printing and ecological risk assessment of polycyclic aromatic hydrocarbons
(PAHs) in the Chenab River, Pakistan. Journal of
Environmental Monitoring, 13(11), 3207–3215.
Hahladakis, J., Smaragdaki, E., Vasilaki, G., & Gidarakos, E.
(2013). Use of sediment quality guidelines and pollution
indicators for the assessment of heavy metal and PAH contamination in Greek surficial sea and lake sediments.
Environmental Monitoring and Assessment, 185(3), 2843–
2853.
Kalf, D. F., Crommentuijn, T., & Vandeplassche, E. J. X. (1997).
Environment quality objectives for polycyclic aromatic hydrocarbons (PAHs). Ecotoxicology & Environmental Safety,
36, 89–97.
Kamal, A., Malik, R. N., Martellini, T., & Cincinelli, A. (2014a).
PAHs exposure biomarkers are associated with clinicchemical changes in the brick kiln workers in Pakistan.
Science of the Total Environment, 490, 521–527.
Kamal, A., Cincinelli, A., Martellini, T., & Malik, R. N. (2014b).
A review of PAH exposure from the combustion of biomass
fuel and their less surveyed effect on the blood parameters.
Environmental Science and Pollution Research, 22(6), 4076–
4098.
Ke, L., Yu, K. S. H., Wong, Y. S., & Tam, N. F. Y. (2005). Spatial
and vertical distribution of polycyclic aromatic hydrocarbons
in mangrove sediments. Science of the Total Environment,
340(1), 177–187.
Kim, K. H., Jahan, S. A., Kabir, E., & Brown, R. J. C. (2013). A
review of airborne polycyclic aromatic hydrocarbons (PAHs)
and their human health effects. Environment International,
60, 71–80.
Kumar, A., Malik, A. K., Tewary, D. K., & Singh, B. (2008). A
review on development of solid phase microextraction fibers
Environ Monit Assess (2016) 188: 378
by sol–gel methods and their applications. Analytica Chimica
Acta, 610(1), 1–14.
Kume, K., Ohura, T., Noda, T., Amagai, T., & Fusay, M. (2007).
Seasonal and spatial trends of suspended-particle associated
polycyclic aromatic hydrocarbons in urban Shizuoka, Japan.
Journal of Hazardous Material, 144, 513–521.
Li, J., Shang, X., Zaho, Z., Tanguay, R. T., Dong, Q., & Huang, C.
(2010). Polycyclic aromatic hydrocarbons in water, sediment,
soil, and plants of the Aojiang River waterway in Wenzhou,
China. Journal of Hazardous Material, 173, 75–81.
Liu, X., Zhang, G., Li, J., Cheng, H. R., Qi, S. H., Li, X. D., &
Jones, K. C. (2007). Polycyclic aromatic hydrocarbons (PAHs)
in the air of Chinese cities. Journal of Environmental
Monitoring, 9(10), 1092–1098.
Liu, Y., Chen, L., Jianfu, Z., Qinghui, H., Zhiliang, Z., &
Hongwen, G. (2008). Distribution and sources of polycyclic
aromatic hydrocarbons in surface sediments of rivers and an
estuary in Shanghai, China. Environmental Pollution, 154,
298–305.
Ma, J., Wu, M. H., Chen, L. L., Chen, Z. Y., & Feng, J. L. (2014).
Polycyclic aromatic hydrocarbons (PAHs) in atmospheric
particulate matter (PM2.5 and PM10) from a suburban area
in Shanghai: levels, sources and risk assessment. Journal of
Shanghai University (Natural Science) 1 04-0521-10:1007–
286.
Mahmood, A., & Malik, R. N. (2014). Human health risk assessment of heavy metals via consumption of contaminated
vegetables collected from different irrigation sources in
Lahore, Pakistan. Arabian Journal of Chemistry, 7(1), 91–99.
Malik, R. N., Rauf, S., Mohammad, A., Eqani, S. A. M. A. S., &
Ahad, K. (2011). Organochlorine residual concentration in
cattle egret from Punjab Province, Pakistan. Environmental
Monitoring and Assessment, 173(1-4), 325–341.
Martinez, E., Gros, M., Lacorte, S., & Barceló, D. (2004).
Simplified procedures for the analysis of polycyclic aromatic
hydrocarbons in water, sediments and mussels. Journal of
Chromatography A, 1047(2), 181–188.
Nikolaou, A., Kostopoulou, M., Petsas, A., Vagi, M., Lofrano, G.,
& Meric, S. (2009). Levels and toxicity of polycyclic aromatic hydrocarbons in marine sediments. Trends in
Analytical Chemistry, 28(6), 653–664.
Nisbet, I. C. T., & LaGoy, P. K. (1992). Toxic equivalency factors
(TEFs) for polycyclic aromatic hydrocarbons (PAHs).
Regulatory Toxicology and Pharmacology, 16, 290–300.
Park, S. U., Kim, J. G., Jeong, M. J., & Song, B. J. (2011). Source
identification of atmospheric polycyclic aromatic hydrocarbons in industrial complex using diagnostic ratios ant multivariate factor analysis. Archives Environmental
Contamination and Toxicology, 60(4), 576–589.
Pies, C., Ternes, T. A., & Hofmann, T. (2008). Identifying sources
of polycyclic aromatic hydrocarbons (PAHs) in soils:
distinguishing point and non-point sources using an extended
PAH spectrum and nalkanes. Journal of Soils and Sediments,
8(5), 312–322.
Qadir, A., & Malik, R. N. (2011). Heavy metals in eight edible fish
species from two polluted tributaries (Aik and Palkhu) of the
River Chenab, Pakistan. Biological Trace Element Research,
143(3), 1524–1540.
Sharma, H., Jain, V. K., & Khan, Z. H. (2007). Characterization
and source identification of polycyclic aromatic
Page 11 of 12 378
hydrocarbons (PAHs) in the urban environment of Delhi.
Chemosphere, 66, 302–310.
Singh, B., Singh, Y., & Sekhon, G. S. (1995). Fertilizers-N use
efficiency and nitrate pollution of groundwater in developing
countries. Journal of Contaminant Hydrology, 20, 167–184.
Soclo, H., Garrigues, P., & Ewald, M. (2000). Origin of polycyclic
aromatic hydrocarbons (PAHs) in coastal marine sediments:
case studies in Cotonou (Benin) and Aquitaine (France)
areas. Marine Pollution Bulletin, 40, 387–396.
Syed, J. H., Malik, R. N., Liu, D., Xu, Y., Wang, Y., Li, J., Zhang,
G., & Jones, K. C. (2013). Organochlorine pesticides in air
and soil and estimated air–soil exchange in Punjab, Pakistan.
Science of the Total Environment, 444, 491–497.
Syed, J. H., Malik, R. N., Li, J., Chaemfa, C., Zhang, G., & Jones,
K. C. (2014). Status, distribution and ecological risk of
organochlorines (OCs) in the surface sediments from the
Ravi River, Pakistan. Science of the Total Environment,
472, 204–211.
Tan, J. H., Bi, X. H., Duan, J. C., Rahn, K. A., Sheng, G. Y., & Fu,
J. M. (2006). Seasonal variation of particulate polycyclic
aromatic hydrocarbons associated with PM10 in
Guangzhou, China. Atmospheric Research, 80, 250–262.
Tian, F. L., Chen, J. W., Qiao, X. L., Wang, Z., Yang, P., Wang, D.
G., & Ge, L. K. (2009). Sources and seasonal variation of
atmospheric polycyclic aromatic hydrocarbons in Dalian,
China: factor analysis with non-negative constraints combined with local source fingerprints. Atmospheric
Environment, 43, 2747–2753.
Villar, P., Callejón, M., Alonso, E., Jiménez, J. C., & Guiraum, A.
(2006). Temporal evolution of polycyclic aromatic hydrocarbons (PAHs) in sludge from wastewater treatment plants:
c o m p a r i s o n b e t w e e n PA H s a n d h e a v y m e t a l s .
Chemosphere, 64(4), 535–541.
Walkley, A., & Black, I. A. (1934). An examination of the
Degtjareff method for determining soil organic matter, and
a proposed modification of the chromic acid titration method.
Soil science, 37(1), 29–38.
Wang, X. F., Cheng, H. X., Xu, X. B., Zhuang, G. M., & Zhao, C.
D. (2008). A wintertime study of polycyclic aromatic hydrocarbons in PM2.5 and PM2.5–10 in Beijing: assessment of
energy structure conversion. Journal of Hazardous Material,
157, 47–56.
Yang, G. P. (2000). Polycyclic aromatic hydrocarbons in the
sediments of the South China Sea. Environmental
Pollution, 108(2), 163–171.
Yang, F., Zhai, Y., Chen, L., Li, C., Zeng, G., & He, Y. (2010). The
seasonal changes and spatial trends of particle associated
polycyclic aromatic hydrocarbons in the summer and autumn
in Changsha City. Atmospheric Research, 96, 122–130.
Yunker, M. B., Snoedon, L. R., Macdoland, R. W., Smith, J. N.,
Fowler, M. G., Malaughlin, F. A., Danyushevskaya, A. I.,
Petrova, V. I., Ivanov, G. I., et al. (1996). Polycyclic aromatic
hydrocarbon composition and potential sources for sediment
samples from the Beaufort and Barents seas. Environmental
Science & Technology, 30, 1310–1320.
Yunker, M. B., Macdonald, R. W., Vingarzan, R., Mitchell, H. R.,
Goyette, D., & Sylvestre, S. (2002). PAHs in the Fraser River
basin: a critical appraisal of PAH ratios as indicators of PAH
source and composition. Organic Geochemistry, 33, 489–
515.
378 Page 12 of 12
Zahra, A., Hashmi, M. Z., Malik, R. N., & Ahmed, Z. (2014).
Enrichment and geo-accumulation of heavy metals and risk
assessment of sediments of the Kurang Nallah—feeding
tributary of the Rawal Lake Reservoir, Pakistan. Science of
the Total Environment, 470, 925–933.
Zhang, Y. X., & Tao, S. (2009). Global atmospheric emission
inventory of polycyclic aromatic hydrocarbons (PAHs) for
2004. Atmospheric Environment, 43, 812–819.
Zhang, Z., Huang, J., Yu, G., & Hong, H. (2004a). Occurrence of
PAHs, PCBs and organochlorine pesticides in the Tonghui
Environ Monit Assess (2016) 188: 378
River of Beijing, China. Environmental Pollution, 130, 249–
261.
Zhang, Z. L., Hong, H. S., Zhou, J. L., & Yu, G. (2004b). Phase
association of polycyclic aromatic hydrocarbons in the
Minjiang River Estuary, China. Science of the Total
Environment, 323, 71–86.
Zheng, T., Ran, Y., & Chen, L. (2014). Polycyclic aromatic hydrocarbons (PAHs) in rural soils of Dongjiang River Basin:
occurrence, source apportionment, and potential human
health risk. Journal of Soils and Sediments, 14, 110–120.