AhR-mediated activities determined by using DR-CALUX assay were observed in urban street dust at mean 40, 29 and 20 ng CALUX-TEQ/g dw for Hanoi, Bangalore and New Delhi, respectively.. I
Trang 1Methylated and unsubstituted polycyclic aromatic hydrocarbons in
street dust from Vietnam and India: Occurrence, distribution and
in vitro toxicity evaluation
Le Huu Tuyen a,b , Nguyen Minh Tue a,b , Shin Takahashi d,* , Go Suzuki c , Pham Hung Viet b ,
Annamalai Subramanian a , Kesav A Bulbule e , Peethambaram Parthasarathy f ,
Alagappan Ramanathan g , Shinsuke Tanabe a
aCenter for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama 790-8577, Japan
bResearch Centre for Environmental Technology and Sustainable Development (CETASD), Hanoi University of Science, 334 Nguyen Trai Street,
Hanoi, Vietnam
cCenter for Material Cycles and Waste Management Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Japan
dAgricultural Faculty, Ehime University, 3-5-7 Tarumi, Matsuyama, Japan
eKle's Nijalingappa College, Bangalore, India
fE-Parisara Pvt Ltd., Bangalore, India
gJawaharlal Nehru University, New Delhi, India
a r t i c l e i n f o
Article history:
Received 29 April 2014
Received in revised form
21 July 2014
Accepted 24 July 2014
Keywords:
MePAHs
AhR
CALUX
Street dust
Vietnam
India
a b s t r a c t
Methylated polycyclic aromatic hydrocarbons (MePAHs), unsubstituted PAHs and AhR-mediated activ-ities were determined in street dust collected from Vietnam and India using a combined approach of chemical analysis and in vitro reporter gene assay MePAHs and PAHs diagnostic ratios indicated that the main sources of MePAHs in Vietnam were pyrogenic emissions, whereas in India there were mixed sources of pyrogenic and petrogenic emissions AhR-mediated activities determined by using DR-CALUX assay were observed in urban street dust at mean 40, 29 and 20 ng CALUX-TEQ/g dw for Hanoi, Bangalore and New Delhi, respectively MePAHs and PAHs contributed only 5% or less to AhR-mediated activity in street dust, indicating the occurrence of unknown AhR agonists The principal contributors to Theoretical-TEQs among target compounds were methyl benz[a]anthracene, benzo[b]- and benzo[k] fluoranthene The present study indicates importance of MePAHs in evaluation of toxic risk related to AhR-mediated activity in urban polluted areas
© 2014 Elsevier Ltd All rights reserved
1 Introduction
Methylated polycyclic aromatic hydrocarbons (MePAHs), one of
PAH derivative groups, are widely distributed in the environment
as is the case with like unsubstituted PAHs MePAHs such as methyl
naphthalene (MeNap), methyl phenanthrene (MePhe), and methyl
chrysen (MeChy) have been identi fied from industrial, petrogenic
or incomplete combustion sources ( Dimitriou-Christidis et al.,
2003; Wang et al., 1999 ) Vietnam and India are two of the six
countries in Asia reported as having the highest air pollution in the
world ( Kim Oanh et al., 2006 ) Well known as a major contributor of
air pollution and potential source for the emission of PAHs ( Tuyen
et al., 2014 ), the number of motorcycles in Hanoi-Vietnam was
reported to be more than 3.9 million in 2011 ( Tran et al., 2012 ), auto vehicles in New Delhi and Bangalore-India was also shown to be high in India with an annual growth of the 10% for car and 9.5% for two-wheelers The growth rate of the number of motorcycles was even higher than the growth rate of population (3.25%) ( Lefevre,
2009 ) The population of motorcycle was reported at 4.2 million units in New Delhi in 2004 ( Goyal et al., 2010 ), reached to 6 million units in 2010 ( Goyal et al., 2013 ) and for Bangalore the numbers are 2.2 million in 2005 ( Lefevre, 2009 ) Motor vehicles have been believed as major contributions of air pollution in urban cities of Asian developing countries ( Agarwal, 2009; Kim Oanh et al., 2012; Goyal et al., 2013; Hien et al., 2014 ).
In the urban environment, street dust is known as a sink for complex mixtures of traf fic related pollutants, contains PAHs and it
is also believed to contain PAHs derivatives ( Tuyen et al., 2014 ) We found signi ficant levels of PAHs (1500 ng/g dry weight) and
AhR-* Corresponding author
E-mail address:shint@agr.ehime-u.ac.jp(S Takahashi)
Contents lists available at ScienceDirect Environmental Pollution
j o u r n a l h o m e p a g e : w w w e l s e v i e r c o m/ l o ca t e / e n v p o l
http://dx.doi.org/10.1016/j.envpol.2014.07.029
0269-7491/© 2014 Elsevier Ltd All rights reserved
Environmental Pollution 194 (2014) 272e280
Trang 2mediated activities (20 ng CALUX-TEQs/g dry weight) in the street
dust with particle-size of less than 500 m m in a previous study It is
expected that the smaller particles may contain higher levels of
vehicle exhaust contaminants as well have more toxic activity
compared to larger particles A previously report also showed that
the highest levels of PAHs were in street dust particles less than
63 m m ( Zhao et al., 2009 ) Therefore, the street dust particle-size
less than 63 m m is preferred selection for chemicals'
determina-tion as well as toxic risk assessment because of their potential
ef-fects on human respiratory system ( Saeedi et al., 2012 ) and
adherence to human skin ( Choate et al., 2006 ).
MePAHs known as generally more persistent and sometimes
more toxic than their unsubstituted analogues ( Sauer and P.B.,
1991 ) The toxicities of MePAHs as well as unsubstituted PAHs are
often involved in binding to the aryl hydrocarbon receptor (AhR),
induction of AhR-related genes and subsequent transformation to
toxic metabolites ( Behnisch et al., 2001 ) Methyl benz[a]anthracene
(MeBaA) has the ability to induce expression of cytochrome P450
1B1 or aldo-keto reductase 1C9 in rat liver epithelial cells similar to
its parent The AhR has been known to be involved in number of
biological processes, such as development and detoxi fication of
exogenous compounds ( Denison and Whitlock, 1995 ) ( Hahn et al.,
2006 ) Using an in vitro reporter gene assay, DR-CALUX, aryl
hy-drocarbon receptor (AhR) mediated activities which had been
known as genotoxic effects produced by many agonist compounds
such as polyhalogenated aromatic hydrocarbons (PHAHs), PAHs or
MePAHs have been determined Some MePAHs/PAHs have been
reported as potent stimulators of AhR activation ( Trilecova et al.,
2011 ) The model rat hepatoma H4IIE cells stably transfected with
luciferase reporter under control of dioxin responsive element
(DRE) have also been used to study the effect of MePAHs on toxic
events associated with tumor promotion ( Machala et al., 2008 ).
Particularly MeBaAs also has ability to induce DNA adduct
forma-tion ( Marvanova et al., 2008 ) Methyl anthrancenes (MeAnt) have
been used for study of their inhibition effects on Gap Junctional
Intercellular Communication (GJIC) in rat liver epithelial cells, in
which MeAnt showed a potent role in tumor promotion and their
biological effect on GJIC were depend on the position of methylated
group ( Upham et al., 1996 ) The MePAHs that have structural
fea-tures with bay-, baylike region could be a potent inhibitor of GJIC
such as MeBaAs (exception of 10-MeBaA), and 1-methy fluorene
(MeFlu), then resulting in disruption of cell proliferation control,
subsequently contributing to tumor promotion ( Weis et al., 1998;
Marvanova et al., 2008 ) Dimethylated PAHs were found to be the
inducers of increased blue sac disease in Japanese medaka and also
to affect its embryonic development ( Rhodes et al., 2005 ).
So far, many studies have been carried out on the
character-ization of MePAHs as well as PAHs in the atmospheric environment
( Fang et al., 2004; Lehndorff and Schwark, 2009; Lee and Dong,
2010; Di Filippo et al., 2010; Lee and Dong, 2011; Ha et al., 2012;
Khairy and Lohmann, 2012, 2013 ), but there is no study on the
evaluation of AhR-related toxicity for methylated PAHs in street
dust and on identi fication of toxically relevant compounds
Inte-grated risk assessment for human health effect due to
contami-nants exposure in polluted areas requires data on contamination
levels and sources However, chemical data of speci fic groups of
contaminants can not provide suf ficient information on potential
toxic effects of the complex mixtures of contaminants in the
environment Therefore, a combination of chemical analysis and
bio assay based on speci fic mode of action could provide useful
information on distribution and toxicity evaluation of
contami-nants The aims of the present study are to determine not only PAHs
but also their methylated analogues in street dust collected from
two Asian developing countries, Vietnam and India and to measure
AhR-mediated activities in street dust by using the dioxin
responsive-chemically activated luciferase gene expression (DR-CALUX) bioassay, in order to evaluate the contamination status and
to assess the toxic contribution of MePAHs and their parent com-pounds in overall toxicity.
2 Material and methods 2.1 Sample collection Street dust samples were collected from the capital cities of Vietnam (Hanoi, n¼ 16) and India (New Delhi, n¼ 7) and a metropolitan city in India (Bangalore, n ¼ 7) during 2012e2013 using straw brooms The broom was washed with Milli-Q water before sample collection A new straw broom was used for each sampling location Duong Quang, a rural village in My Hao district, Hung Yen province, Vietnam, was chosen as a reference site (Fig S1andTable S1) Approximately 300 g of street dust was collected from an area of 50 m in length and 0.5 m in width and kept in an aluminum foil pocket washed with acetone and hexane and placed inside a zip-locked polyethylene bag After collection, the samples were preserved at25C until analysis
2.2 Sample pre-treatment and extraction Chemicals from one gram of each air-dried and 63mm sieved street dust samples were extracted with a mixture of distilled acetone/hexane and then distilled toluene using a rapid solvent extractor (SE100, Mitsubishi Chemical Analytech) according to
a previously reported method (Tue et al., 2010) A 0.1 g-equivalent portion of the crude extract was then concentrated, solvent-exchanged into 0.1 ml biochemical-grade dimethyl sulfoxide and stored at 4C for in vitro determination of AhR-mediated activities using the DR-CALUX assay The remaining extract was used for chemical analysis of MePAHs and PAHs Every set of seven samples was accompa-nied with a procedural blank
2.3 Detection of the AhR-mediated activity The AhR-mediated activities of all crude extract were determined individually using the DR-CALUX assay (expressed in CALUX-TEQ) This assay utilize the rat hepatoma cell line H4IIE (BioDetection Systems, The Netherlands) stably transfected with thefirefly luciferase gene containing a multimerized DRE (dioxin response element) in front of a minimal promoter (Aarts et al., 1995; Garrison et al., 1996) All assays were performed following BioDetection Systems's protocol described else-where (Suzuki et al., 2004, 2006) Briefly, approximately 80,000 cells/well were seeded on 96-well plates After 24 h of incubation at 37C and 5% CO2, the cells were treated with conditioned medium (0.8% DMSO) containing either the 2,3,7,8-tetrachlorobenzo-p-dioxin (TCDD) as a standard reference in a series of concentra-tions (0e37.5 nM) or the samples (diluted by a factor of 1e1000) Each measurement was done in triplicates Plates were incubated for 24 h at 37C, 5% CO2 After exposure the cells were subjected to luminescence measurement The AhR agonist activities were derived from the diluted samples with similar response to 1e3 pM TCDD (usually 300 to 1000 time dilution), and expressed in amounts of TCDD equivalent (CALUX-TEQ) per gram dry weight (dw) The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate cell viability in these diluted samples (Suzuki et al., 2013)
2.4 Chemical analysis Each of the remaining extract was spiked with deuterated PAH surrogate stan-dards and then cleaned-up using 1.2% deactivated alumina chromatography and activated silica gel chromatography The target compounds were eluted from alumina chromatography column with 150 ml acetone/hexane (v/v: 30/70), and concentrated to 1 ml After, passing through the activated silica gel chromatography column the target compounds were eluted with 80 ml of 95:5 hexane:dichloro-methane, and then spiked with chrysen-d12(Chy-d12) as internal standard Finally, the extracts were concentrated in 1 ml of iso-octane before being subjected to gas chromatography-mass spectrometry analyses All solvents were purchased from Wako Pure Chemical Ind., Osaka, Japan and distilled before use Compounds analyzed in this study were parent PAHs including naphthalene (Nap), acenaph-thylene (Acy), acenaphthene (Ace),fluorene (Flu), phenanthrene (Phe), anthracene (Ant),fluoranthene (Fluh), pyrene (Pyr), benzo[c]phenanthrene (BcPh), cyclopenta [c,d]pyrene (CPP), benz[a]anthracene (BaA), chrysene (Chy), benzo[b]-, benzo[k]-, and benzo[j]fluoranthene (BbF, BkF and BjF), benzo[e]- and benzo[a]pyrene (BeP and BaP), indeno[1,2,3-c,d]pyrene (IDP), dibenz[a,h]anthracene (DBA), benzo[g,h,i]per-ylene (BgP), dibenzo[a,h]-, dibenzo[a,i]-, dibenzo[a,l]pyrene (DBahP, DBaiP and DBalP); MePAHs including 1- and 2-MePhe, 2- and 9-MeAnt, 1-, 2-, 3- and 6-MeChy, 1-MePyr, 1-, 2- 3-, 4-, 5-, 6-, 7-, 9- and 10-MeBaA, 10-MeBaP) 3-methylcholanthrene (MCA), 3,6-Me2Phe, 9,10-Me2Ant, and 7,12-Me2BaA For surrogate standards,
Nap-d8, Acy-d8, Phe-d10, Ant-d10, Flush-d10, Pyr-d10, BaA-d12, BaP-d12and BgP-d12were used All surrogate and internal standards were purchased from SigmaeAldrich The target compounds were identified and quantified by a gas chromatography mass spectrometry (GCeMS) following the method described previously (Tuyen et al.,
2014) with slight modification Briefly, we used Agilent model 7890A coupled with a mass spectrometer 5975C MSD and equipped a DB1 MS capitally GC column (30 m 0.25 mm, 0.25mm), for the determination of MePAHs and PAHs Average L.H Tuyen et al / Environmental Pollution 194 (2014) 272e280
Trang 3recovery rates of surrogate standards of PAHs were from 97% to 116% (Table S2).
Every set of seven samples was accompanied with a procedural blank for checking
interfering compounds in the GCeMS analysis
2.5 Calculations of Theo-TEQs
The contributions by PAHs and MePAHs to AhR-mediated activities in the street
dust extracts can be evaluated by comparison of CALUX-TEQs measured with
DR-CALUX and theoretical TEQs (Theo-TEQs) of MePAHs and PAHs Theo-TEQ of a
compound was calculated as shown in Equation(1) The DR-CALUX relative potency
(REP) of PAHs, MePAHs relative to TCDD is summarized inTable S3
Theo- TEQsðng TCDD=gÞ ¼ Concentrationðng=gÞ REP (1)
2.6 Cancer risk assessment
The incremental lifetime cancer risk (ILCR) adopted from (US EPA, 1991) and
described in some publications (Chen and Liao, 2006; Wang et al., 2011; Peng et al.,
2011), was slightly modified by using adaptive parameters and used to
quantita-tively estimate the exposure risk for street dust PAHs Eqs.(2)e(4) was applied to
evaluate cancer risk of human exposure to PAHs via ingestion, dermal contact and
inhalation, respectively
ILCRsIngestion¼CS
CSFIngestionp3ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiBW=70
IRIngestion EF ED
ILCRsDermal¼CS
CSFDermalp3ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiBW=70
SA AF ABS EF ED
ILCRsInhalation¼CS
CSFInhalationp3ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiBW=70
IRInhalation EF ED
where CS is the BaP-equivalent concentration of dust (mg kg1), Carcinogenic po-tencies relative to BaP (Larsen and Larsen, 1998) was applied to calculate BaP-equivalent concentrations (Table S2) CSFs are carcinogenic slope factors based on the cancer-causing ability of BaP through ingestion (CSFIngestion), dermal contact (CSFDermal) and inhalation (CSFInhalation), BW is body weight, EF is exposure fre-quency, ED is exposure duration, IRinhalatin is inhalation rate, IRingestion is dust ingestion rate, SA is dermal exposure area, AF is dermal adherence factor, ABS is dermal adsorption fraction, AT is averaging life span, PEF is particle emission factor The detail parameters and their values are summarized inTable S4 The risks for children and adults were calculated separately The total risks were the sum of risks associated with each exposure route
2.7 Statistical analysis The R software package version 2.15.2 was used to perform statistical analyses Pearson's correlation coefficient analysis (log-transformed concentration of target compounds, at 95 percent confidence interval) was applied to examine the rela-tionship between MePAHs and their corresponding unsubstituted compounds in street dust samples In order to examine the significance of the difference in
AhR-Table 1
Concentrations (ranges and arithmetic means, ng/g dw) of MePAHs and PAHs in street dust
Nd: not detected
L.H Tuyen et al / Environmental Pollution 194 (2014) 272e280
Trang 4used the Wilcoxon rank sum test A p value of<0.05 is considered as indicating
statistically significant
3 Results and discussion
3.1 AhR-mediated activity
Higher AhR-mediated activities in street dust were found for
metropolitan and urban areas of Hanoi (20e68, mean 40 ng/g dw),
New Delhi (11e29, mean 20 ng/g dw) and Bangalore (19e47, mean
29 ng/g dw) than for the rural site, Duong Quang (8e35, mean
18 ng/g dw) ( Fig S2 ) The CALUX-TEQs in urban street dust from
Vietnam and India were comparable to those reported for urban
dust from the United States (median: 43 ng CALUX-TEQ/g dw)
( Andrysík et al., 2011 ), suggesting the presence of large amount AhR
agonists such as PAHs as well as their derivatives in Vietnam and
India's street dust ( Fig S2 ) The CALUX-TEQs in the 63 m m fraction
of the dust samples from Hanoi and Duong Quang analyzed in this
study were from 2 to 3 times higher than the levels in the coarser
fraction ( 500 m m) reported in our previous study ( Fig S2 ) ( Tuyen
et al., 2014 ), suggesting that smaller particles contained larger
amount of AhR agonists.
3.2 Concentrations, pro files and potential sources of PAHs
Higher concentrations of S23PAHs were found in street dust
from Hanoi (530e4700, mean 1900 ng/g dw), Bangalore
(670e1800, mean 1100 ng/g dw), and New Delhi (650e1700, mean
1100 ng/g dw) than in street dust from Duong Quang (260e1000,
mean 620 ng/g dw) ( Table 1 , Fig S2 ) BbF, BkF, IDP, Chy, BaA, BjF, the
most potent AhR agonists among PAHs in vitro ( Machala et al.,
2001 ), were found at one to five fold higher concentrations in the
urban sites (Hanoi, Bangalore and New Delhi) than in the rural site
(Duong Quang) Concentrations of PAHs recommended for
carci-nogenic screening by the European Union and the US
Environ-mental Protection Agency (EU- and EPA-PAHs) in Hanoi street dust
were among the highest levels and were 2 times higher than those
in dust from New Delhi, Bangalore and 3 times higher than Duong
Quang ( Table 1 ), whereas, BaP concentrations in Hanoi street dust
were 4 times higher than those in dust from Duong Quang, and comparable to New Delhi and slightly higher than the value from Bangalore only The compounds having the same molar mass are assumed to have similar physicochemical properties PAHs diag-nostic ratios are commonly used as tools for identi fication of pollution emission sources ( Katsoyiannis et al., 2011; Dvorska et al.,
2011 ) The sources were also reported in many previous studies ( Table S5 ) The results obtained from calculation of the IDP/ (IDP þ BgP) and BaP/BgP ratios were plotted in Fig 1 , indicating that vehicular traf fic was the major contributor of PAHs in all sampling sites ( Yunker et al., 2002; Fang et al., 2004; LI et al., 2006; Kume
et al., 2007; Ravindra et al., 2008; Peng et al., 2011 ) The diag-nostic ratios of Flu/(Flu þ Pyr) > 0.5 indicate that the major source
of PAHs was gasoline and <0.5 indicate a major source from diesel ( Ravindra et al., 2008 ) We observed this ratio ranged from 0.03 to 0.07 (mean 0.05) for New Delhi and Bangalore, from 0.01 to 0.09 (mean 0.05) for Hanoi and 0.02 to 0.22 (mean 0.13) for Duong Quang, suggesting that major source was by the combustion of gasoline rather than diesel In addition, the ratios of Fluh/ (Fluh þ Pyr) ranged from 0.52 to 0.59 (mean 0.56, Duong Quang), 0.31 to 0.54 (mean 0.46, Hanoi), 0.40 to 0.50 (mean 0.47, New Delhi), 0.31 to 0.49 (mean 0.39, Bangalore) and the ratios of IDP/ (IDP þ BgP) ranged from 0.27 to 0.42 (mean 0.35, Duong Quang), 0.24 to 0.37 (mean 0.30, Hanoi), 0.25 to 0.36 (mean 0.29, New Delhi), 0.25 to 0.34 (mean 0.31, Bangalore), which indicated that pyrogenic pathways was main emission sources in Duong Quang, Hanoi, and New Delhi whereas emission sources in Bangalore could
be pyrogenic and petrogenic ( Katsoyiannis et al., 2011 ) The strong positive correlation between the concentrations of BgP and total PAHs for Hanoi (Pearson's r ¼ 0.96, p < 0.05), Duong Quang (Pearson's r ¼ 0.91, p < 0.05), New Delhi (Pearson's r ¼ 0.75,
p < 0.05) and Bangalore (Pearson's r ¼ 0.60, p > 0.05) found in street dust for all study locations also indicated that vehicles emission is the major source of PAHs in these areas ( Fig S3 ) ( Baek et al., 1991 ) However, although diagnostic ratios are useful tools for identi fi-cation of PAHs emission sources in environment samples including dust particles or airborne But still, there are limitations due to PAHs distribution are depend on the size of particles, organic carbon contents or transportation and degradation of different particles
Fig 1 Plot of IDP/(IDPþ BgP) and BaP/BgP in street dust from different regions
L.H Tuyen et al / Environmental Pollution 194 (2014) 272e280
Trang 5phase ( Tobiszewski and Namiesnik, 2012 ) PAHs pro files showed
that Pyr, Fluh, Phe, BbF þ BkF, Chy, BgP, BaP, IDP, BeP, BjF and BaA
were predominant in all sampling sites, whereas Ant dominated in
Indian street dust but not in Vietnam street dust ( Fig 2 ).
3.3 Concentration and pro files of MePAHs
Total and individual MePAH concentrations are shown in
Table 1 Total MePAH concentrations in Hanoi and Bangalore were
similar (mean 750 and 740 ng/g dw, respectively) and 2 and 3 times
fold higher than those in New Delhi and Duong Quang (mean 390
and 250 ng/g dw, respectively) Methyl phenanthrenes, potent AhR
agonists in reporter gene assay ( Barron et al., 2004; Vondra^cek
et al., 2007 ), were predominant in all sampling sites ( Table 1 ,
Fig S2 ) MeBaAs, which had been reported as potent in vitro AhR
agonist ( Marvanova et al., 2008 ), were found in the urban sites
(Hanoi, Bangalore, New Delhi) at signi ficantly higher levels than in
the rural site ( Table 1 ) 1-MeChy, a signi ficant contributor which
was found to possess EROD-inducing potency in rainbow trout liver
cell line (RTL-W1) ( Brack and Schirmer, 2003 ), was at signi ficant
level in Hanoi ( Table 1 ) Congener pro files of MePAHs indicated that MeBaAs were predominant in all urban sites, whereas MePhes were the most abundant in the rural site ( Fig 3 ) By examining the ratios between MePAHs and their corresponding unsubstituted compounds, we found that MeBaAs were more abundant than BaA except in Duong Quang ( Fig S4 ), MePhes more abundant than Phe
in Hanoi and, MeAnts more abundant than Ant in Bangalore only ( Table 1 , Fig S4 ).
3.4 Correlations between MePAHs and corresponding unsubstituted PAH (PPAHs) and their potential sources
We found strong correlations between the concentrations of MePAHs and PPAHs in street dust from all study locations (Pear-son's r ¼ 0.86e0.99, p < 0.05), suggesting that MePAHs and their corresponding unsubstituted PAHs were from the same emission sources ( Fig S5 ) Ratios of MePhe and Phe can be used to identify the emission sources of PAHs: it can be assumed that PAHs could be released into the environment from fossil fuels combustion if MePhe/Phe >1 and the source could be petrogenic emission if
Fig 2 Profiles of PAHs in street dust from different regions (The error bars are the variation of chemical proportions in different samples)
Fig 3 Profiles of MePAHs in street dust from different regions (The error bars represent the ranges)
L.H Tuyen et al / Environmental Pollution 194 (2014) 272e280
Trang 6MePhe/Phe >1.5 ( Boonyatumanond et al., 2006 ) The average of
MePhe/Phe was <1 for New Delhi and Duong Quang, indicating that
MePAHs were from pyrogenic sources in these places This ratio
was slightly higher than 1 in Hanoi, indicating that the sources of
MePAHs in this site were mostly pyrogenic ( Fig 4 A) These results
are consistent with PAH diagnostic ratios of IDP/(IDP þ BgP) But,
the results from Bangalore indicated that the sources of MePAHs
could be mostly petrogenic Ratio between sums of MeChy/Chy was
also useful for the identi fication of emission sources, and PAHs
were also identi fied as pyrogenic if the ratio of MeChy/Chy below 1
( Saha et al., 2009 ): The values of MeChy/Chy in Fig 4 B indicates that
the emission in Hanoi and Duong Quang could be related to
pyro-genic, but in New Delhi and Bangalore this could be related to
petrogenic On the other hand, MePyr/Pyr ( Fig 4 C) values were to
be < 0.5 in all sampling sites, suggesting that pyrogenic activities
were the main emission sources ( Saha et al., 2009 ) Moreover,
MePAHs/PAHs shown in Fig 4 D was at <0.8 in almost all sampling
point of Hanoi, Duong Quang, and New Delhi again con firming that
pyrogenic was mainly emission sources in these site whereas
emission sources in Bangalore could be mostly petrogenic ( Saha
et al., 2009 ).
3.5 Contribution by MePAHs and PAHs to the AhR-mediated
toxicity
The contributions by PAHs and MePAHs to AhR-mediated
ac-tivities in the street dust extracts were evaluated by comparison of
CALUX-TEQs measured with DR-CALUX and theoretical TEQs
(Theo-TEQs) of MePAHs and PAHs Theo-TEQ of a compound was
calculated by multiplying the concentration of the target
com-pound with its TCDD-relative potency in CALUX assays ( Table S3 ).
Higher Theo-TEQs (among PAHs) were observed in Hanoi (mean
0.86 ng/g dw), New Delhi (0.38 ng/g dw), Bangalore (0.34 ng/g dw)
than Duong Quang (mean 0.25 ng/g dw) Signi ficantly higher
Theo-TEQs of MePAHs were also observed in urban sites (Hanoi: mean
0.56 ng/g dw; New Delhi: mean 0.41 ng/g dw; Bangalore: mean
0.59 ng/g dw) than the rural site (Duong Quang: mean 0.01 ng/g
dw) The contribution of MePAHs and PAHs accounted in average of
5% of AhR-mediated activity in street dust from New Delhi, 4% for
Hanoi, 3% for Bangalore and 2% for Duong Quang Besides, much larger proportions of unexplained activities (95%e98%) than Theo-TEQs of total MePAHs/PAHs in the CALUX-Theo-TEQs indicate the exis-tence of unknown AhR agonists Our previous study documented that contribution of dioxin-related compounds to AhR-mediated activity in road dust from Hanoi was very small (~0.1%) ( Tuyen
et al., 2014 ) In addition, we found no signi ficant correlations be-tween CALUX-TEQs and total PAHs/MePAHs (p > 0.05) Therefore, potential compounds contributing as unknown AhR-agonists in the road dust may be other PAHs-related compounds (e.g., heterocyclic PAHs, halogenated-, oxygenated-PAHs) ( Larsson et al., 2014 ) Among MePAHs and PAHs determined in this study, MeBaAs was the major contributor to Theo-TEQs, which had ranged from 3
to 64%, for all sampling sites, followed by BbF þ BkF (ranged from 21% to 62% in the urban areas) or IDP (ranged from 9 to 25% for all sampling sites) ( Fig 5 ) The contribution of MeBaAs to AhR-mediated activity was even higher than those of their corre-sponding unsubstituted compounds ( Fig S6 ) These results suggest importance of MeBaAs as well as PPAHs in the evaluation of toxic risk related to AhR-mediated activity in the Asian metropolitan and urban areas.
3.6 Cancer risk assessment Probabilistic risk assessment for personal exposure to carcino-genic PAHs showed that an ILCR between 106and 104indicates potential risk, whereas ILCR greater than 104indicates high po-tential health risk ( US EPA, 2005 ) The acceptable level is equal to or lower than 106( US EPA, 2005 ) Our estimated results suggest that children and adults in both study sites in Vietnam and India are exposed to high potential carcinogenic risk via both dust ingestion and dermal contact pathways (detail in Table 2 ) In which, highest levels of cancer risk for both children and adults were observed in Hanoi ( Table 2 ) Particularly, cancer risk levels via ingestion for children and adults from urban site (Hanoi, New Delhi, and Ban-galore) were signi ficantly higher than those in rural site (Duong Quang) The cancer risk levels via dermal contact for children and adults from urban site in Vietnam and India were slightly higher than those of children and adults from rural site ILCRs of inhalation
Fig 4 Plots of MePAHs/PAHs ratios in street dust
L.H Tuyen et al / Environmental Pollution 194 (2014) 272e280
Trang 7pathway were almost negligible when compared to ingestion and
dermal contact pathways ( Table 2 ) The results of cancer risk
assessment found in Hanoi also indicated higher potential cancer
risk due to exposure to smaller dust particles than the lager
par-ticles, as reported in our previous study ( Tuyen et al., 2014 ) The
abundance of methylated derivatives of some carcinogenic PAHs,
such as MeBaAs contribute at least with 50% of the total Theo-TEQs,
suggests that carcinogenic potency of MePAHs should also be
considered But so far, a carcinogenic potency factor of MePAHs has
not been studied Therefore, the cancer risk model for MePAHs
should be studied and established in future.
4 Conclusions
This is the first report on toxic contribution of MePAHs to
AhR-mediated activities in street dust from Asian metropolitan and
ur-ban areas of developing countries, Vietnam and India Pro files of
MePAHs/PAHs determined by chemical analysis indicated that
py-rogenic combustion is the major sources of MePAHs in Hanoi,
Vietnam, but in Indian urban areas they were mixed of pyrogenic and petrogenic origin Total concentrations of MePAHs in Bangalore were slightly higher than their corresponding unsubstituted com-pounds In contrast, PAH concentrations found in Duong Quang, Hanoi and New Delhi street dust were higher than their methyl derivatives The comparison between Theo-TEQs of MePAHs/PAHs and CALUX-TEQs indicates occurrence of unknown AhR agonists in the street dust Further studies are necessary to identify potential compounds and to evaluate other PAHs-related compounds such as heterocyclic PAHs, halogenated-, oxygenated-PAHs for under-standing their potencies on AhR-mediated activity The present study showed that MeBaAs, some of the most abundant methyl PAHs, has higher contribution to AhR-mediated activities than corresponding unsubstituted PAHs The fact that higher concen-trations of MePAHs and PAHs are bound to street dust with smaller diameter size, resulting in the higher AhR-mediated activities was observed, suggest that contaminant monitoring as well as toxic effect evaluation of ambient air particles in these areas are need be done elaborately in the further studies.
Fig 5 Contribution of individual MePAHs and PAHs to total Theo-TEQs (DQ: Duong Quang, HN: Hanoi, ND: New Delhi, BL: Bangalore)
Table 2
Estimated values of incremental life time cancer risk
95% Percentile 6.7 105 7.4 105 1.7 104 2.6 104 2.6 109 1.2 108
95% Percentile 3.3 104 3.6 104 8.2 104 1.3 103 1.3 108 5.7 108
95% Percentile 1.4 104 1.5 104 3.4 104 5.3 104 5.4 109 2.4 108
95% Percentile 1.3 104 1.4 104 3.2 104 5.1 104 5.1 109 2.2 108
L.H Tuyen et al / Environmental Pollution 194 (2014) 272e280
Trang 8This study was partly supported by Grants-in-Aid for Scienti fic
Research (A: 25257403) from Japan Society for the Promotion of
Science (JSPS) and the Environment Research and Technology
Development Fund (K123001 and 3K133010) from the Ministry of
the Environment, Japan The award of a JSPS postdoctoral
fellow-ship to N M Tue (P 13072) is also acknowledged.
Appendix A Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.envpol.2014.07.029
References
Aarts, J.M., Denison, M.S., Cox, M.A., Schalk, M.A., Garrison, P.M., Tullis, K., de
Haan, L.H., Brouwer, A., 1995 Species-specific antagonism of Ah receptor action
by 2, 20, 5, 50-tetrachloro-and 2, 20, 3, 30, 4, 40-hexachlorobiphenyl Eur J
Pharmacol Environ Toxicol Pharmacol 293, 463e474
Agarwal, T., 2009 Concentration level, pattern and toxic potential of PAHs in traffic
soil of Delhi, India J Hazard Mater 171, 894e900.http://dx.doi.org/10.1016/
j.jhazmat.2009.06.081
Andrysík, Z., Vondracek, J., Marvanova, S., Ciganek, M., Neca, J., Pencíkova, K.,
Mahadevan, B., Topinka, J., Baird, W.M., Kozubík, A., Machala, M., 2011
Activa-tion of the aryl hydrocarbon receptor is the major toxic mode of acActiva-tion of an
organic extract of a reference urban dust particulate matter mixture: the role of
polycyclic aromatic hydrocarbons Mutat Res Mol Mech Mutagen 714, 53e62
http://dx.doi.org/10.1016/j.mrfmmm.2011.06.011
Baek, S.O., Field, R.A., Goldstone, M.E., Kirk, P.W., Lester, J.N., Perry, R., 1991 A review
of atmospheric polycyclic aromatic hydrocarbons: sources, fate and behavior
Water Air Soil Pollut 60, 279e300.http://dx.doi.org/10.1007/BF00282628
Barron, M.G., Heintz, R., Rice, S.D., 2004 Relative potency of PAHs and heterocycles
as aryl hydrocarbon receptor agonists infish Mar Environ Res 58, 95e100
http://dx.doi.org/10.1016/j.marenvres.2004.03.001
Behnisch, P.A., Hosoe, K., Sakai, S., 2001 Bioanalytical screening methods for dioxins
and dioxin-like compounds d a review of bioassay/biomarker technology
Environ Int 27, 413e439.http://dx.doi.org/10.1016/S0160-4120(01)00028-9
Boonyatumanond, R., Wattayakorn, G., Togo, A., Takada, H., 2006 Distribution and
origins of polycyclic aromatic hydrocarbons (PAHs) in riverine, estuarine, and
marine sediments in Thailand Mar Pollut Bull 52, 942e956.http://dx.doi.org/
10.1016/j.marpolbul.2005.12.015
Brack, W., Schirmer, K., 2003 Effect-directed identification of oxygen and sulfur
heterocycles as major polycyclic aromatic cytochrome P4501A-inducers in a
contaminated sediment Environ Sci Technol 37, 3062e3070
Chen, S.-C., Liao, C.-M., 2006 Health risk assessment on human exposed to
envi-ronmental polycyclic aromatic hydrocarbons pollution sources Sci Total
En-viron 366, 112e123.http://dx.doi.org/10.1016/j.scitotenv.2005.08.047
Choate, L.M., Ranville, J.F., Bunge, A.L., Macalady, D.L., 2006 Dermally adhered soil:
1 Amount and particle-size distribution Integr Environ Assess Manag 2,
375e384.http://dx.doi.org/10.1002/ieam.5630020409
Denison, M.S., Whitlock, J.P., 1995 Xenobiotic-inducible transcription of
cyto-chrome P450 genes J Biol Chem 270, 18175e18178.http://dx.doi.org/10.1074/
jbc.270.31.18175
Di Filippo, P., Riccardi, C., Pomata, D., Buiarelli, F., 2010 Concentrations of PAHs, and
nitro- and methyl- derivatives associated with a size-segregated urban aerosol
Atmos Environ 44, 2742e2749 http://dx.doi.org/10.1016/j.atmosen
v.2010.04.035
Dimitriou-Christidis, P., Harris, B.C., McDonald, T.J., Reese, E., Autenrieth, R.L., 2003
Estimation of selected physicochemical properties for methylated naphthalene
compounds Chemosphere 52, 869e881
http://dx.doi.org/10.1016/S0045-6535(03)00288-1
Dvorska, A., Lammel, G., Klanova, J., 2011 Use of diagnostic ratios for studying
source apportionment and reactivity of ambient polycyclic aromatic
hydro-carbons over Central Europe Atmos Environ 45, 420e427.http://dx.doi.org/
10.1016/j.atmosenv.2010.09.063
Fang, G.-C., Chang, C.-N., Wu, Y.-S., Fu, P.P.-C., Yang, I.-L., Chen, M.-H., 2004
Char-acterization, identification of ambient air and road dust polycyclic aromatic
hydrocarbons in central Taiwan, Taichung Sci Total Environ 327, 135e146
http://dx.doi.org/10.1016/j.scitotenv.2003.10.016
Garrison, P.M., Tullis, K., Aarts, J.M.M.J.G., Brouwer, A., Giesy, J.P., Denison, M.S., 1996
Species-specific Recombinant cell lines as bioassay systems for the detection of
2,3,7,8-Tetrachlorodibenzo-p-dioxin-like chemicals Fundam Appl Toxicol 30,
194e203.http://dx.doi.org/10.1006/faat.1996.0056
Goyal, P., Jaiswal, N., Kumar, A., Dadoo, J.K., Dwarakanath, M., 2010 Air quality
impact assessment of NOx and PM due to diesel vehicles in Delhi Transp Res
Part Transp Environ 15, 298e303.http://dx.doi.org/10.1016/j.trd.2010.03.002
Goyal, P., Mishra, D., Kumar, A., 2013 Vehicular emission inventory of criteria
pol-lutants in Delhi SpringerPlus 2, 216
http://dx.doi.org/10.1186/2193-1801-2-Ha, S.Y., Kim, G.B., Yim, U.H., Shim, W.J., Hong, S.H., Han, G.M., 2012 Particle-size distribution of polycyclic aromatic hydrocarbons in urban road dust of Masan, Korea Arch Environ Contam Toxicol 63, 189e198.http://dx.doi.org/10.1007/ s00244-012-9765-4
Hahn, M.E., Karchner, S.I., Evans, B.R., Franks, D.G., Merson, R.R., Lapseritis, J.M.,
2006 Unexpected diversity of aryl hydrocarbon receptors in non-mammalian vertebrates: insights from comparative genomics J Exp Zool A Comp Exp Biol 305A, 693e706.http://dx.doi.org/10.1002/jez.a.323
Hien, P.D., Hangartner, M., Fabian, S., Tan, P.M., 2014 Concentrations of NO2, SO2, and benzene across Hanoi measured by passive diffusion samplers Atmos Environ 88, 66e73.http://dx.doi.org/10.1016/j.atmosenv.2014.01.036 Katsoyiannis, A., Sweetman, A.J., Jones, K.C., 2011 PAH molecular diagnostic ratios applied to atmospheric sources: a critical evaluation using two decades of source inventory and air concentration data from the UK Environ Sci Technol
45, 8897e8906.http://dx.doi.org/10.1021/es202277u Khairy, M.A., Lohmann, R., 2012 Field validation of polyethylene passive air sam-plers for parent and alkylated PAHs in Alexandria, Egypt Environ Sci Technol
46, 3990e3998.http://dx.doi.org/10.1021/es300012u Khairy, M.A., Lohmann, R., 2013 Source apportionment and risk assessment of polycyclic aromatic hydrocarbons in the atmospheric environment of Alexan-dria, Egypt Chemosphere 91, 895e903 http://dx.doi.org/10.1016/j.chemosph ere.2013.02.018
Kim Oanh, N.T., Thuy Phuong, M.T., Permadi, D.A., 2012 Analysis of motorcyclefleet
in Hanoi for estimation of air pollution emission and climate mitigation co-benefit of technology implementation Atmos Environ 59, 438e448.http:// dx.doi.org/10.1016/j.atmosenv.2012.04.057
Kim Oanh, N.T., Upadhyay, N., Zhuang, Y.-H., Hao, Z.-P., Murthy, D.V.S., Lestari, P., Villarin, J.T., Chengchua, K., Co, H.X., Dung, N.T., Lindgren, E.S., 2006 Particulate air pollution in six Asian cities: spatial and temporal distributions, and asso-ciated sources Atmos Environ 40, 3367e3380 http://dx.doi.org/10.1016/ j.atmosenv.2006.01.050
Kume, K., Ohura, T., Noda, T., Amagai, T., Fusaya, M., 2007 Seasonal and spatial trends of suspended-particle associated polycyclic aromatic hydrocarbons in urban Shizuoka Jpn J Hazard Mater 144, 513e521.http://dx.doi.org/10.1016/ j.jhazmat.2006.10.079
Larsen, J.C., Larsen, P.B., 1998 Air Pollution and Health The Royal Society of Chemistry, Cambridge, UK
Larsson, M., Hagberg, J., Giesy, J.P., Engwall, M., 2014 Time-dependent relative potency factors for polycyclic aromatic hydrocarbons and their derivatives in the H4IIE-luc bioassay Environ Toxicol Chem 33, 943e953.http://dx.doi.org/ 10.1002/etc.2517
Lee, B.-K., Dong, T.T.T., 2010 Effects of road characteristics on distribution and toxicity of polycyclic aromatic hydrocarbons in urban road dust of Ulsan, Korea
J Hazard Mater 175, 540e550.http://dx.doi.org/10.1016/j.jhazmat.2009.10.039 Lee, B.-K., Dong, T.T.T., 2011 Toxicity and source assignment of polycyclic aromatic hydrocarbons in road dust from urban residential and industrial areas in a typical industrial city in Korea J Mater Cycles Waste Manag 13, 34e42.http:// dx.doi.org/10.1007/s10163-010-0287-8
Lefevre, B., 2009 Long-term energy consumptions of urban transportation: a pro-spective simulation of “transporteland uses” policies in Bangalore Energy Policy 37, 940e953.http://dx.doi.org/10.1016/j.enpol.2008.10.036
Lehndorff, E., Schwark, L., 2009 Biomonitoring airborne parent and alkylated three-ring PAHs in the greater cologne conurbation I: temporal accumulation pat-terns Environ Pollut 157, 1323e1331 http://dx.doi.org/10.1016/j.envpol.2 008.11.037
Li, X., Ma, L., Liu, X., Fu, S., Cheng, H., Xu, X., 2006 Polycyclic aromatic hydrocarbon
in urban soil from Beijing, China J Environ Sci 18, 944e950.http://dx.doi.org/ 10.1016/S1001-0742(06)60019-3
Machala, M., Svihalkova-Sindlerova, L., Pencíkova, K., Krcmar, P., Topinka, J., Milcova, A., Novakova, Z., Kozubík, A., Vondracek, J., 2008 Effects of methylated chrysenes on AhR-dependent and -independent toxic events in rat liver epithelial cells Toxicology 247, 93e101 http://dx.doi.org/10.1016/ j.tox.2008.02.008
Machala, M., Vondracek, J., Blaha, L., Ciganek, M., Neca, J., 2001 Aryl hydrocarbon receptor-mediated activity of mutagenic polycyclic aromatic hydrocarbons determined using in vitro reporter gene assay Mutat Res Toxicol Environ Mutagen 497, 49e62.http://dx.doi.org/10.1016/S1383-5718(01)00240-6 Marvanova, S., Vondracek, J., Penccíkova, K., Trilecova, L., Krcmarr, P., Topinka, J., Novakova, Z., Milcova, A., Machala, M., 2008 Toxic effects of methylated benz[a] anthracenes in liver cells Chem Res Toxicol 21, 503e512.http://dx.doi.org/ 10.1021/tx700305x
Peng, C., Chen, W., Liao, X., Wang, M., Ouyang, Z., Jiao, W., Bai, Y., 2011 Polycyclic aromatic hydrocarbons in urban soils of Beijing: status, sources, distribution and potential risk Environ Pollut 159, 802e808 http://dx.doi.org/10.1016/ j.envpol.2010.11.003
Ravindra, K., Sokhi, R., Vangrieken, R., 2008 Atmospheric polycyclic aromatic hy-drocarbons: source attribution, emission factors and regulation Atmos Envi-ron 42, 2895e2921.http://dx.doi.org/10.1016/j.atmosenv.2007.12.010 Rhodes, S., Farwell, A., Hewitt, L.M., Mackinnon, M., Dixon, D.G., 2005 The effects of dimethylated and alkylated polycyclic aromatic hydrocarbons on the embryonic development of the Japanese medaka Ecotoxicol Environ Saf 60, 247e258 http://dx.doi.org/10.1016/j.ecoenv.2004.08.002
Saeedi, M., Li, L.Y., Salmanzadeh, M., 2012 Heavy metals and polycyclic aromatic hydrocarbons: pollution and ecological risk assessment in street dust of Tehran
J Hazard Mater 227e228, 9e17.http://dx.doi.org/10.1016/j.jhazmat.2012.04.047 L.H Tuyen et al / Environmental Pollution 194 (2014) 272e280
Trang 9Saha, M., Togo, A., Mizukawa, K., Murakami, M., Takada, H., Zakaria, M.P.,
Chiem, N.H., Tuyen, B.C., Prudente, M., Boonyatumanond, R., Sarkar, S.K.,
Bhattacharya, B., Mishra, P., Tana, T.S., 2009 Sources of sedimentary PAHs in
tropical Asian waters: differentiation between pyrogenic and petrogenic
sour-ces by alkyl homolog abundance Mar Pollut Bull 58, 189e200 http://
dx.doi.org/10.1016/j.marpolbul.2008.04.049
Sauer, T., P.B, 1991 The use of defensible analytical chemical measurements for oil
spill In: Natural Resource Damage Assessment Proc 1991 Oil Spill Conf,
pp 363e369
Suzuki, G., Takigami, H., Kushi, Y., Sakai, S., 2006 Time-course changes of mixture
effects on AhR binding-dependent luciferase activity in a crude extract from a
compost sample Toxicol Lett 161, 174e187
Suzuki, G., Takigami, H., Kushi, Y., Sakai, S.-I., 2004 Evaluation of mixture effects in a
crude extract of compost using the CALUX bioassay and HPLC fractionation
Environ Int 30, 1055e1066.http://dx.doi.org/10.1016/j.envint.2004.05.005
Suzuki, G., Tue, N.M., Malarvannan, G., Sudaryanto, A., Takahashi, S., Tanabe, S.,
Sakai, S., Brouwer, A., Uramaru, N., Kitamura, S., Takigami, H., 2013 Similarities
in the endocrine-disrupting potencies of indoor dust andflame retardants by
using human osteosarcoma (U2OS) cell-based reporter gene assays Environ
Sci Technol 47, 2898e2908.http://dx.doi.org/10.1021/es304691a
Tobiszewski, M., Namiesnik, J., 2012 PAH diagnostic ratios for the identification of
pollution emission sources Environ Pollut 162, 110e119 http://dx.doi.org/
10.1016/j.envpol.2011.10.025
Tran, N.L., Chikaraishi, M., Zhang, J., Fujiwara, A., 2012 Exploring day-to-day
vari-ations in the bus usage behavior of motorcycle owners in hanoi Procedia e Soc
Behav Sci 43, 265e276.http://dx.doi.org/10.1016/j.sbspro.2012.04.099
Trilecova, L., Krckova, S., Marvanova, S., Pĕncíkova, K., Krcmar, P., Neca, J.,
Hulinkova, P., Palkova, L., Ciganek, M., Milcova, A., Topinka, J., Vondracek, J.,
Machala, M., 2011 Toxic effects of methylated benzo[a]pyrenes in rat liver
stem-like cells Chem Res Toxicol 24, 866e876 http://dx.doi.org/10.1021/
tx200049x
Tue, N.M., Suzuki, G., Takahashi, S., Isobe, T., Trang, P.T.K., Viet, P.H., Tanabe, S., 2010
Evaluation of dioxin-like activities in settled house dust from Vietnamese
E-waste recycling sites: relevance of polychlorinated/brominated
dibenzo-p-dioxin/furans and dioxin-like PCBs Environ Sci Technol 44, 9195e9200
http://dx.doi.org/10.1021/es102505j
Tuyen, L.H., Tue, N.M., Suzuki, G., Misaki, K., Viet, P.H., Takahashi, S., Tanabe, S., 2014
Aryl hydrocarbon receptor mediated activities in road dust from a metropolitan
area, HanoidVietnam: contribution of polycyclic aromatic hydrocarbons (PAHs) and human risk assessment Sci Total Environ Hallogenated Persistent Org Pollut (Dioxin2013, Daegu/Korea) 491e492, 246e254.http://dx.doi.org/ 10.1016/j.scitotenv.2014.01.086
Upham, B.L., Weis, L.M., Rummel, a M., Masten, S.J., Trosko, J.E., 1996 The effects of anthracene and methylated anthracenes on gap junctional intercellular communication in rat liver epithelial cells Fundam Appl Toxicol Off J Soc Toxicol 34, 260e264
US EPA, 1991 Risk Assessment Guidance for Superfund: Volume I - Human Health Evaluation Manual (Part B, Development of Risk-based Preliminary Remedia-tion Goals) (Policies& Guidance) (US Environ Prot Agency Wash DC)
US EPA, 2005 Guidelines for Carcinogen Risk Assessment Vondra^cek, J., ^Svihalkova-^Sindlerova, L., P^en^cíkova, K., Marvanova, S., Kr^cmar^, P., Ciganek, M., Ne^ca, J., Trosko, J.E., Upham, B., Kozubík, A., Machala, M., 2007 Concentrations of methylated naphthalenes, anthracenes, and phenanthrenes occurring in Czech river sediments and their effects on toxic events associated with carcinogenesis in rat liver cell lines Environ Toxicol Chem 26, 2308e2316.http://dx.doi.org/10.1897/07-161R.1
Wang, W., Huang, M., Kang, Y., Wang, H., Leung, A.O.W., Chung, K., Hung, M., 2011 Polycyclic aromatic hydrocarbons (PAHs ) in urban surface dust of Guangzhou, China: status, sources and human health risk assessment Sci Total Environ
409, 4519e4527.http://dx.doi.org/10.1016/j.scitotenv.2011.07.030 Wang, Z., Fingas, M., Shu, Y.Y., Sigouin, L., Landriault, M., Lambert, P., Turpin, R., Campagna, P., Mullin, J., 1999 Quantitative characterization of PAHs in burn residue and soot samples and differentiation of pyrogenic PAHs from petrogenic PAHsThe 1994 Mobile Burn study Environ Sci Technol 33, 3100e3109 http://dx.doi.org/10.1021/es990031y
Weis, L.M., Rummel, a M., Masten, S.J., Trosko, J.E., Upham, B.L., 1998 Bay or baylike regions of polycyclic aromatic hydrocarbons were potent inhibitors of Gap junctional intercellular communication Environ Health Perspect 106, 17e22 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, 489e515 http://dx.doi.org/10.1016/S0146-6380(02)00002-5
Zhao, H., Yin, C., Chen, M., Wang, W., Chris, J., Shan, B., 2009 Size distribution and diffuse pollution impacts of PAHs in street dust in urban streams in the Yangtze River Delta J Environ Sci 21, 162e167 http://dx.doi.org/10.1016/S1001-0742(08)62245-7
L.H Tuyen et al / Environmental Pollution 194 (2014) 272e280