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Levels of polycyclic aromatic hydrocarbons (PAHs) in the Densu River Basin of Ghana


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The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in Densu River Basin in Ghana were measured using gas chromatograph. Surface water samples were collected from nine stations, namely, Potroase, Koforidua Intake, Suhyien, Mangoase, Asuboi, Nsawam Bridge, Afuaman, Ashalaga, and Weija Intake in the Densu Basin. Total PAH concentrations varied from 13.0 to 80.0 μg/mL in the Densu River, with a mean value of 37.1 μg/mL. The two- to three-ring PAHs (low-molecular-weight PAHs) were found to be dominant in the Densu River Basin. Total PAH concentrations showed the following pattern: Koforidua Intake (80.0 μg/mL) > Asuboi (50.8 μg/mL) > Afuaman (47.9 μg/mL) > Weija Intake (45.0 μg/mL) > Suhyien (27.6 μg/mL) > Nsawam (23.5 μg/mL) > Ashalaja (22.9 μg/mL) > Potroase (23.3 μg/mL) > Mangoase (13.0 μg/mL). According to the Agency for Toxic Substances and Disease Registry (ATSDR), background levels of PAHs in drinking water supplies in the USA range from 0.004 to 0.024 μg/mL. PAH levels from all sites exceeded the range set by ATSDR. B[a]P contributed the highest carcinogenic exposure equivalent (0.3 μg/mL), followed by B[a]A (0.132 μg/mL) and B[b]F (0.08 μg/mL), contributing 52.6%, 23.2%, and 4.6%, respectively, of the total carcinogenicity of surface water PAH in the Densu River Basin. The carcinogenic potency was estimated to be 0.57 μg/mL. The presence of PAHs was an indication of the water sources being contaminated, with potential health implications.
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Environmental Monitoring
and Assessment
An International Journal
Devoted to Progress in the Use
of Monitoring Data in Assessing
Environmental Risks to Man
and the Environment
ISSN 0167-6369
Volume 174
Combined 1-4
Environ Monit Assess (2010)
DOI 10.1007/s10661-010-1471-
Levels of polycyclic aromatic
hydrocarbons (PAHs) in the Densu River
Basin of Ghana
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Environ Monit Assess (2011) 174:471–480
DOI 10.1007/s10661-010-1471-y
Levels of polycyclic aromatic hydrocarbons (PAHs)
in the Densu River Basin of Ghana
Joyce Amoako ·Osmund D. Ansa-Asare ·
Anthony Y. Karikari ·G. Dartey
Received: 17 July 2009 / Accepted: 7 April 2010 / Published online: 12 May 2010
© Springer Science+Business Media B.V. 2010
Abstract The concentrations of 16 polycyclic aro-
matic hydrocarbons (PAHs) in Densu River Basin
in Ghana were measured using gas chromato-
graph. Surface water samples were collected from
nine stations, namely, Potroase, Koforidua Intake,
Suhyien, Mangoase, Asuboi, Nsawam Bridge,
Afuaman, Ashalaga, and Weija Intake in the
Densu Basin. Total PAH concentrations varied
from 13.0 to 80.0 μg/mL in the Densu River, with
a mean value of 37.1 μg/mL. The two- to three-
ring PAHs (low-molecular-weight PAHs) were
found to be dominant in the Densu River Basin.
Total PAH concentrations showed the following
pattern: Koforidua Intake (80.0 μg/mL) >Asuboi
(50.8 μg/mL) >Afuaman (47.9 μg/mL) >Weija
Intake (45.0 μg/mL) >Suhyien (27.6 μg/mL) >
Nsawam (23.5 μg/mL) >Ashalaja (22.9 μg/mL) >
Potroase (23.3 μg/mL) >Mangoase (13.0 μg/mL).
According to the Agency for Toxic Substances
and Disease Registry (ATSDR), background lev-
els of PAHs in drinking water supplies in the USA
range from 0.004 to 0.024 μg/mL. PAH levels
J. Amoako (B)·O. D. Ansa-Asare ·
A. Y. Karikari ·G. Dartey
Environmental Chemistry Division,
CSIR Water Research Institute,
P. O. Box AH 38, Achimota, Ghana
from all sites exceeded the range set by ATSDR.
B[a]P contributed the highest carcinogenic expo-
sure equivalent (0.3 μg/mL), followed by B[a]A
(0.132 μg/mL) and B[b]F (0.08 μg/mL), contribut-
ing 52.6%, 23.2%, and 4.6%, respectively, of the
total carcinogenicity of surface water PAH in
the Densu River Basin. The carcinogenic potency
was estimated to be 0.57 μg/mL. The presence of
PAHs was an indication of the water sources being
contaminated, with potential health implications.
Keywords PAHs ·Gas chromatograph ·
Contamination ·Densu River Basin ·
Surface water
Water pollution by organic compounds, mostly
known to be toxic or carcinogenic, is of con-
siderable concern worldwide. Polycyclic aromatic
hydrocarbons (PAHs) are a group of ubiquitous
organic pollutants containing two or more fused
benzene rings, of great environmental concern be-
cause of the documented carcinogenicity in exper-
imental animals and the widespread occurrence of
several of its members (Manoli et al. 2000).
Due to their ubiquitous occurrence, recal-
citrance, and suspected carcinogenicity and
mutagenicity, PAHs are included in the US
Environmental Protection Agency (EPA) and in
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472 Environ Monit Assess (2011) 174:471–480
the European Union priority lists of pollutants.
The US EPA fixed 16 parent PAHs as priority
pollutants, the latest being effective from 1997
(Baumard et al. 1997; Mastral and Callén 2000;
Magi et al. 2002; Szolar et al. 2002; Schubert et al.
2003), some of which are considered to be possible
or probable human carcinogens. Endocrine-
disrupting activities of PAHs have also been
recently reported (Clemons et al. 1998; Brun et al.
PAHs have been detected in the atmosphere,
water, soil, sediments, and food (Ferreira 2001).
PAHs are introduced into the environment
through natural and anthropogenic combustion
processes. Anthropogenic sources include auto-
mobile exhaust and tire degradation, industrial
emissions from catalytic cracking, air blowing of
asphalt, coking coal, domestic heating emissions
from coal, oil, gas, and wood, refuse incineration,
and biomass burning. The major mobile anthro-
pogenic sources are vehicles and tobacco smok-
ing (Shui-Jen et al. 2003). Volcanic eruptions and
forest and prairie fires are among the major nat-
ural sources of PAHs in the atmosphere (Baek
et al. 1991; Manoli et al. 2000). In general, more
PAHs form when materials burn at low temper-
atures, such as in wood fires or cigarettes. High-
temperature furnaces produce fewer PAHs. Fires
can form fine PAH particles. They bind to ash
particles and can move long distances through the
air. Atmospheric deposition has been regarded as
a main pathway for the loading of PAHs to many
water bodies (Golomb et al. 1997).
As streams and rivers, lakes, and ponds are
frequently used for potable water supply and the
reuse of water is common, contamination of water
sources is particularly undesirable (Manoli and
Samara 1999). Therefore, PAH distributions in
the environment and potential human health risks
have become the focus of much attention.
The Densu River, for its size, is one of the
most exploited rivers in Ghana (WRC 2003). It
traverses several towns (Koforidua, Nsawam, Ak-
wadum, etc.) and serves as the main source of
water supply for a number of communities. The
river is confronted by three main agents of degra-
dation: bad farming practices, deforestation, and
pollution (domestic and industrial wastewater).
The activities of farmers (high use of fertilizer
and other chemicals), especially large-scale com-
mercial farming enterprises in the catchment of
the river, are causing a lot of havoc both to the
water quality and quantity. The Densu River is
presently one of the most polluted rivers in the
country due to the impact of growing population
densities, industrialization, and intensification of
agricultural activities (WRC 2003). The Densu
River enters the Weija reservoir which is one of
the two main sources of water supply systems for
In Ghana, very limited studies on the moni-
toring of PAHs in surface waters are available.
Available water quality data (physicochemical) on
the Densu Basin include those of Amuzu (1975),
Kpekata and Biney (1979), Biney (1987), Ansa-
Asare (1992,1996), and Karikari and Ansa-Asare
(2006). All these studies concentrated on other
forms of pollution and degradation, but not on
PAHs. The current study focuses on identifying
and characterizing PAHs in light of their toxic
and carcinogenic effects on human health and
aquatic environment using quantitative gas chro-
matograph with micro-electron capture detector
(GC-μECD) method.
Materials and methods
Standard PAHs (16 components) from the
National Institute of Standard Technology
(NIST) of concentration 60 μg/ml, deuterated
PAHs internal standards (IS) in cyclohexane
3,6,-dimethylphenanthrene (3,6-DMP) and β,β-
Ginaphthyl (β,β-BN) and dichloromethane
were obtained from Sigma, BDH, and Supelco.
Working standards of these micro-pollutants
(PAHs) were prepared by combining the standard
mixture with the corresponding IS stock solution,
respectively. These solutions were further diluted
with hexane to prepare calibration solutions in the
range 1–15 μg/ml. All solvents (dichloromethane,
cyclohexane, hexane, and methanol) used for
sample preparation were of high-performance
liquid chromatography (HPLC) grade. Organic-
free distilled water was used.
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Environ Monit Assess (2011) 174:471–480 473
Study area
The Densu Basin located between latitude
20N and longitude 010Wto
035W (Fig. 1) has an estimated drainage
area of 2,564 km2(WRC 2003). It takes its
source from the Atewa-Atwiredu mountain
range near Kibi in the Eastern Region of Ghana
and flows southwards for 116 km entering the
Weija Lake at Ashalaja. It discharges into the
Sakumo II Lagoon, 4 km south of the Weija Dam,
before subsequently emptying into the Atlantic
0 5 10 15 K m.
0 5 10 Miles
Asuboi Mangoase
Sampling Station
Catchment Boundary
Weija Intake
Nsawam Bridge
Fig. 1 Map of Densu Basin (Ghana) indicating sampling sites
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474 Environ Monit Assess (2011) 174:471–480
Ocean at Bortianor situated southwest of Accra
(Amuzu 1975). The Densu River catchment
area encompasses the following rivers which are
tributaries: Adaiso, Suhyien, Doboro, Nsaki, and
Kuia (Fig. 1), all of which flow through densely
populated areas, forests, and areas of intense
farming activities where fertilizers and pesticides
are heavily used (Ayibotele and Tuffuor-Darko
1979). Mainly crystalline rocks, comprising five
formations, namely, Birimian, Granites, Togo
series, Dahomayean, and Accraian, underlie the
basin. With the exception of Accraian, the rest are
Precambrian. The dominant soils are ochrosols,
with patches of gleisols and lithosols.
The inhabitants are mainly peasant farmers
who grow foodstuffs, vegetables, fruits, and cash
crops (e.g., cocoa). In addition, many large-scale
commercial farmers grow crops for the export
market. Timber and lumber are extracted from
the forest in the basin. The river waters are ex-
tensively used for drinking and other domestic
Sampling and sample treatment
Nine sampling stations were selected based on
accessibility and closeness to major population
centers where human activities can indirectly be
assessed. The nine sampling stations have been
arranged from upstream near the headwaters
to downstream. Sampling followed this order:
Potroase—S1, Koforidua Intake—S2, Suhyien—
S3, Mangoase—S4, Asuboi—S5, Nsawam
Bridge—S6, Afuaman—S7, Ashalaga—S8, and
Weija Intake—S9. The sampling stations included
two intake points (headworks) of the Ghana
Water Company Limited, namely, Koforidua and
The study was conducted between March and
December 2004, covering dry and rainy seasons.
Each station was sampled three times. The surface
water samples were collected at a depth of 20–
30 cm (to ensure proper mixing) into pre-cleaned
1-L glass containers. The water samples were pre-
served at pH <2 with the addition of 5 mL conc.
HCl. All the samples were tightly sealed and kept
in an ice chest stored at 4C and transported to
the Council for Scientific and Industrial Research-
Water Research Institute laboratory and kept in a
refrigerator (at 4C) for a maximum of 1 week and
analyzed using Agilent 6890 gas chromatograph.
Sampling was mainly confined to the midstream
of the river courses except on few occasions where
unavailability of a boat limited sampling to the
Sample extraction, analytical quality control,
and statistical analysis
Sample extraction
IS in cyclohexane were added to the water sam-
ples. The internal standards were 3,6-DMP and
β,β-BN for analysis with gas chromatograph using
flame ionization detector (GC-FID). The sam-
ples were Soxhlet-extracted with cyclohexane for
8 h. The extracts were purified by partitioning
dimethylformamide/water. The PAHs were then
eluted with cyclohexane from columns filled with
5 g of silica gel deactivated with 15% water.
The identification and quantification of PAHs was
accomplished using a gas chromatograph (GC;
Hewlett-Packard 6890 A) with split/splitless injec-
tor and FID. The column is a capillary column
HP-5MS (60 m ×0.25 mm i.d. ×0.25 μm film
thickness). Nitrogen (purity of 99.9999%) was
used as the carrier gas at a constant flow of
1.4 mL/min. A 2 μL volume was injected by
applying a hot splitless injection technique. The
temperature program of the oven was as follows:
from 60C (initial time, 3 min) to 120Cata
rate of 10C/min, 120C to 280Catarateof
5C/min, and held at 280C for 10 min. The GC
chemstation (version A.08.04) was controlled by
computer workstation. Identification of the PAH
compounds was performed by comparing GC
retention time with those of authentic stan-
dards. Quantification of individual compounds
was based on comparison of peak areas with those
of the recovery standards.
Analytical quality control
All data were subjected to strict quality control
procedures. For PAHs, deuterated internal stan-
dards 3,6-DMP and β,β-BN were to compensate
for losses during sample extraction and work-up.
Before sample analysis, relevant standards were
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Environ Monit Assess (2011) 174:471–480 475
analyzed to check column performance, peak
height, and resolution and the limits of detection.
For each set of samples to be analyzed, a solvent
blank, a standard mixture, and a procedural blank
were run in sequence to check for contamination,
peak identification, and quantification. Standard
reference material (SRM 1491) from National In-
stitute of Standards and Technology (NIST) was
used for GC calibration and relative accuracies. In
general, 16 different individual PAHs have been
quantified. A given amount of distilled water was
taken and then spiked with known amount of
Esso Marine Special Oil (certified reference ma-
terial from Norwegian Water Research Institute,
NIVA) and analyzed as normal sample. Blank
samples of distilled water were also analyzed to
ensure that there was no petroleum compounds
present, which will give too high extraction yields.
The recovery efficiencies of 16 individual PAHs
were determined by processing a solution con-
taining known PAH concentrations through the
same experimental procedure used for the sam-
ples. Total recovery efficiency of PAHs in this
study ranged from 73.9% to 110.8% and averaged
95.8%. RSD (%) of recovery efficiency was up to
17%, and the value of potential error for PAHs
analysis was estimated to be 18%. Procedural
blanks were analyzed concurrently with the sam-
ples. No detectable concentrations of PAHs were
present in any of the procedural blanks.
Statistical analysis
The Spearman’s rank correlation was used to
examine the correlation between low molecular
weight (LM-PAHs, two- to three-ringed PAHs)
and high molecular weight (HM-PAHs, five- to
six-ringed PAHs); between LM-PAHs and mid-
dle molecular weight (MM-PAHs, four-ringed
PAHs); and between MM-PAHs and HM-PAHs
in the water samples for the various stations.
A probability value of p<0.05 was considered
as statistically significant in this study (data not
PAH identification and quantification
The following PAH species were identified and
quantified in this study: two-ring, naphthalene;
three-ring, including acenaphthylene, acenaph-
thene, fluorene, phenanthrene, anthracene; four-
ring, including fluoranthene, pyrene, benzo[a]
anthracene, chrysene; five-ring, including benzo
[b]fluoranthene, benzo[ j,k]fluoranthene, benzo[a]
pyrene (B[a]P); and six-ring, including indeno[1,
2,3-cd]pyrene, dibenzo[a,h]anthracene, and benzo
[ghi]perylene. The total PAH concentration was
regarded as the sum of the concentrations of 16
PAH species for each collected sample. In or-
der to understand PAH homologue distribution
for each collected sample, the concentrations of
PAH species with LM-PAHs (containing two- to
three-ringed PAHs), MM-PAHs (containing four-
ringed PAHs), and HM-PAHs (containing five- to
six-ringed PAHs) were also determined.
Results and discussion
The mean concentration ranges of individual and
total PAHs in the Densu River Basin at the vari-
ous stations are shown in Table 1. The results are
compared to the background levels of PAHs in
drinking water from USA which range from 0.004
to 0.024 μg/mL (ATSDR 1995).
Table 1 Mean concentrations (μg/mL) of PAHs in water from Densu River
Potroase Koforidua Suhyien Mangoase Asuboi Nsawam Afuaman Ashalaja Weija Mean SD
intake intake
LM 5.73 63.33 20.4 6.15 40.86 10.52 40.10 14.75 34.10 26.22 19.62
MM 14.18 7.67 2.75 2.90 5.91 7.99 2.49 1.70 5.40 5.67 3.94
HM 3.42 9.04 4.44 3.95 3.98 4.97 5.28 6.41 5.57 5.23 1.70
Total 23.33 80.04 27.59 13.00 50.75 23.48 47.87 22.86 45.07 37.12 25.26
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476 Environ Monit Assess (2011) 174:471–480
PAH concentrations in Densu River water
Total PAH concentrations ranged from 13.0 to
80.0 μg/mL in the Densu River, with mean value
of 37.1 μg/mL (Table 1). The highest concentra-
tion of total PAH (80.0 μg/mL) was observed at
Koforidua intake, S2 (Fig. 2). With increasingly in-
tense, agricultural activities, urban and industrial
development, and expansion work at the intake,
the amount of PAHs detected at the intake may
be related to urban runoffs and vehicular exhaust
emission. At the time of sampling, there were
vehicular trucks working during the expansion
work at the Koforidua Intake point. Similarly,
high concentration (50.7 μg/mL) was also found at
Asuboi, S5. The station is close to heavy vehicular
traffic. In addition, there were a lot of commer-
cial vegetable farms and cattle rearing upstream
of the river at Asuboi. Runoffs from farm lands
and many other non-point sources may contribute
to the high concentrations of PAHs detected at
Therefore, the analytical results from this study
indicated that total PAHs in water from the sta-
tions increased in the order: Koforidua intake >
Asuboi >Afuaman >Weija intake >Suhyien >
Nsawam >Ashalaja >Potroase >Mangoase.
Levels of PAHs from all the nine sampling sites
exceeded background levels of PAHs in drink-
ing water from USA which range from 0.004 to
0.024 μg/mL.
PAHs compositional pattern
The compositional pattern of PAHs by molecular
weight along the basin (upstream to downstream)
is shown in Fig. 3. It can be observed that two-
and three-ringed PAHs (naphthalene, acenaph-
thylene, acenaphthene, fluorene, phenanthrene,
and anthracene) constituting the LM-PAHs are
the most abundant PAHs, which averaged 64% of
total PAHs (Table 2) in the Densu River Basin,
followed by four-ringed PAHs constituting the
MM-PAHs which averaged 19% of total PAHs
in the Densu River Basin. The five- to six-ringed
PAHs constituting the HM-PAHs which averaged
17% of total PAHs in the Densu River Basin
were the least present. Work done by Wei et al.
(2009) revealed higher concentrations of dissolved
PAHs (LM-PAHs) than that of particulate PAHs
at many sites of the Daliao River in China. Com-
mon sources of PAHs are vehicle exhaust, coal
tar, and municipal or industrial activities that in-
volve combustion. High-molecular-weight PAHs
enter rivers and streams through atmospheric de-
position and stormwater runoff. During their at-
mospheric residence, PAHs are redistributed in
the atmosphere between the gas and the particulate
Fig. 2 Mean
concentrations of low
molecular weight
(LM-PAHS), comprising
two to three-ringed PAHs
middle molecular weight
(MM-PAHs), comprising
four-ringed PAHs, and
high molecular weight
(HM-PAHs), comprising
five to six-ringed PAHs in
the Densu Basin
alongside total PAH
Koforidua Intake
Weija Intake
PAHs (µg/ml)
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Environ Monit Assess (2011) 174:471–480 477
Fig. 3 Composition
pattern of total PAHs in
Densu Basin showing the
low molecular weight
(LM-PAHS), comprising
the two to three-ringed
PAHs, middle molecular
weight (MM-PAHs),
comprising four-ringed
PAHs, and high
molecular weight
(HM-PAHs), comprising
five to six-ringed PAHs of
the various sites sampled
Potroase Koforidua
Suhyien Mangoase Asuboi Nsawam Afuaman Ashalaja Weija
phase (Bourotte et al. 2005), transported over
long distances, and enter water bodies by wet and
dry deposition and or by gas–water interchange
(Fang et al. 2004).
At Potroase, the mean LM-PAHs and HM-
PAHs were 24.6% and 14.7% of the total PAHs,
respectively, indicating moderate influence of par-
ticulates from the atmosphere. Thus, at Potroase,
MM-PAHs (60.8%) dominated the water. Ko-
foridua Intake recorded LM-PAHs of 79.1%
of the total PAHs. It recorded HM-PAHs of
11.3%. This indicated moderate influence of par-
ticulates from the atmosphere. Low levels of
MM-PAHs (9.6%) were also recorded for the
station. The sources of PAHs may be from wa-
ter running off asphalt roads and exhaust from
cars and trucks. The LM-PAHs also dominated
at Suhyien, recording 74% of the total PAHs. It
recorded HM-PAHs of 16% and MM-PAHs of
10%. Mangoase station also showed low MM-
PAHs of 22.3% and HM-PAHs of 30.4%. The
LM-PAHs for Mangoase was 47.3%, being the
dominant PAHs. The low levels of HM-PAHs
for Suhyien and Mangoase could be attributed to
moderate atmospheric deposition and stormwater
runoff. At Asuboi, the LM-PAHs recorded 80.5%
of the total PAHs, dominating over the rest of
Table 2 Percentage
compositional pattern of
PAHs within the entire
PAHs Percentage
LM 64
MM 19
HM 17
the PAH. The MM-PAHs and the HM-PAH were
11.6% and 7.8%, respectively. Similar trend of
LM-PAHs dominating the rest of the distribu-
tion pattern was observed at Nsawam, Afuaman,
Ashalaja, and Weija Intake stations. At low to
moderate temperature, as in the wood stove (Lake
et al. 1979) or as from the combustion of coal,
low-molecular-weight total PAH compounds are
abundant. At high temperature, such as vehicle
emissions, the high-molecular-weight total PAH
compounds are dominant (Laflamme and Hites
In terms of MM-PAHs and HM-PAHs, be-
tween the different sites, no significant difference
in PAH concentrations was observed. Concentra-
tions of PAH between low-molecular-weight and
high-molecular-weight PAHs at Asuboi showed
a statistically significant difference (p=0.046).
This could probably be due to increased par-
ticulate matter deposition from the atmosphere.
The difference between LM-PAHs and HM-
PAHs at Koforidua showed a trend toward a
non-significant difference (p=0.050). The cor-
responding difference between LM-PAHs and
MM-PAHs for Suhyien, Afuaman, and Ashalaja
showed a trend toward a non-statistical signifi-
cance (p=0.050).
Assessing PAH exposure profiles
Evidence that mixtures of PAHs are carcino-
genic in humans comes primarily from occupa-
tional studies of workers. Cancer associated with
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478 Environ Monit Assess (2011) 174:471–480
exposure to PAH-containing mixtures in humans
occurs predominantly in the lung and skin follow-
ing inhalation and dermal exposure, respectively
(WHO 1998). Several PAH species including
benzo[a]pyrene have been classified into proba-
ble (2A) or possible (2B) human carcinogens by
the International Agency for Research on Can-
cer (IARC 1987). Benzo[a]pyrene is a five-ring
(C20H12 ) compound which is mutagenic for hu-
man cells in culture (Osborne and Crosby 1987)
and carcinogenic in animal assays (Cerna et al.
2000). The toxic equivalent factor (TEF) for B[a]P
is 1 according to Bostrom et al. (2002), which
is highest among all the PAHs. Therefore, the
risk associated with the intake of carcinogenic
PAHs from Densu River Basin was estimated
using TEFs for individual PAHs. TEFs have been
devised as a means of comparing the carcinogenic-
ity of the individual PAHs to the carcinogenicity
of B[a]P. Till date, only a few proposals of TEFs
for PAHs are available (Masih et al. 2008). In
this work, TEFs given by Tsai and Shih (2004)
were employed. Benzo[a]pyrene equivalents for
each carcinogenic PAH were calculated by mul-
tiplying mean concentrations with corresponding
TEF values (Table 3). The above method has the
main advantage of being relatively easy to apply
in the environments affected by human sources,
Table 3 BaPeq exposure profiles in Densu River Basin
PAHs Mean TEFs BaP exposure
Naphthalene 5.06 0.001 0.00506
Acenaphthylene 13.63 0.001 0.01363
Acenaphthene 3.73 0.001 0.00373
Fluorene 1.51 0.001 0.00151
Phenanthrene 0.90 0.001 0.0009
Anthracene 1.39 0.01 0.0139
Fluoranthene 0.63 0.001 0.00063
Pyrene 1.58 0.001 0.00158
Benzo[a]anthracene 1.32 0.1 0.132
Chrysene 2.14 0.01 0.0214
Benzo[b]fluoranthene 0.80 0.1 0.08
Benzo[k]fluoranthene 2.18 –
Benzo[a]pyrene 0.30 1 0.3
Indeno[1,2,3-cd]pyrene 0.96 –
Dibenzo[a,h]anthracene 0.45 –
Benzo[ghi]perylene 0.53 0.01 0.0053
Total 37.11 1.23 0.57
however may underestimate risk due to not all
PAH but only limited compounds are considered
(WHO/IPCs 1998). The mean concentration of
total PAH of 37.1 μg/mL corresponds to a B[a]P
equivalent exposure of 0.57 μg/mL with respect
to carcinogenicity. B[a]P contributed the high-
est carcinogenic exposure equivalent (0.3 μg/mL),
followed by B[a]A (0.132 μg/mL) and B[b]F
(0.08 μg/mL), contributing 52.6%, 23.2%, and
4.6%, respectively, of the total carcinogenicity of
surface water PAH in the Densu River Basin.
Sixteen priority PAHs were determined in wa-
ter from nine locations from the Densu River
Basin. The levels of PAHs in the Densu River
Basin ranged from 13.0 to 80.0 μg/mL, exceed-
ing the background levels of PAHs in drink-
ing water from USA (0.004–0.024 μg/mL). The
PAH profiles of water samples revealed that the
dominant PAHs were of low molecular weight
(two- and three-ringed) as naphthalene, acenaph-
thylene, acenaphthene, fluorene, phenanthrene,
and anthracene. The concentration of PAH
for the various stations increased in the order
Koforidua Intake >Asuboi >Afuaman >Weija
Intake >Suhyien >Nsawam >Ashalaja >
Potroase >Mangoase. Asuboi showed a statis-
tically significant difference (p=0.046) between
LM-PAH and HM-PAH. Using a TEF approach,
the mean concentration of total PAH equates
to about 0.57 μg/mL of B[a]P exposure with re-
spect to carcinogenic potency. B[a]P contributed
the highest carcinogenic exposure equivalent
(0.3 μg/mL), followed by B[a]A (0.132 μg/mL)
and B[b]F (0.08 μg/mL). The findings point to the
need to establish a monitoring program for these
organic micro-pollutants since the river is a source
of drinking water supply.
Acknowledgements The authors wish to thank the gov-
ernment of Ghana for sponsoring this research, staff of the
Council for Scientific and Industrial Research-Water Re-
search Institute (CSIR-WRI), the Ghana Water Company
Limited for their assistance during sampling at their intake
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... In the last few decades, environmental PAHs and their distribution, sources and potential risk to ecological systems have been extensively studied in the coastal regions worldwide (Lim et al. 2007, Ren et al. 2010, Amoako et al. 2011, Montuori and Triassi 2012, Jaward et al. 2012, Sun et al. 2016, Zheng et al. 2016. However, there are few studies monitoring concentrations of PAHs in the Bangladeshi environments (Zuloaga et al. 2013, Nøst et al. 2015. ...
... In general, the ∑PAHs concentrations in the present study were comparable or lower than those measured in the coastal areas of the Persian Gulf (Sinaei and Mashinchian 2014), Gomti River Basin (Malik et al. 2011), Mumbai harbor line, India (Dhananjayan et al. 2012) and Daya Bay, China (Zhou and Maskaoui 2003). However, measured ∑PAHs concentrations in the Bangladeshi coastal area were far higher than those reported in surface water from the coastal areas of China (Ren et al. 2010, Li et al. 2015, Zheng et al. 2016, Singapore (Lim et al. 2007), Pakistan (Aziz et al. 2014), Ghana (Amoako et al. 2011), Australia (Shaw et al. 2004), Italy (Montuori and Triassi 2012), and Mexico (Jaward et al. 2012) (Table 2). Furthermore, the contamination of ∑PAHs in dissolved phases could be classified into four grades: micro-polluted (10-50 ng/L); lightly polluted (50-250 ng/L); moderately polluted (250-1000 ng/L) and heavily polluted (>1000 ng/L) (Chen 2008, Li et al. 2015, Cao et al. 2010. ...
Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) in the surface water from the coastal areas of Bangladesh were analyzed by GC-MS/MS. Samples were collected in winter and summer, 2015. The total concentration of PAHs (∑PAHs) showed a slight variation in the two seasons, which varied from 855.4 to 9653.7 ng/L in winter and 679.4 to 12639.3 ng/L in summer, respectively. The levels of ∑PAHs were comparable to or relatively higher than other coastal areas around the world. The areas with recent urbanization and industrialization (Chittagong, Cox's Bazar and Sundarbans) were more contaminated with PAHs than the unindustrialized area (Meghna Estuary). Generally, 2-3-ring PAHs were the dominant compounds. Molecular ratios suggested that PAHs in the study areas could be originated from both pyrogenic and petrogenic sources. The risk assessment revealed the extremely high ecological risk of PAHs, indicating an intense attention should be paid to PAHs pollution in the coastal areas of Bangladesh.
... In Africa, a great number of studies has been conducted in identifying the sources and occurrence of PAHs in environmental samples as well as the risks they pose to public health. Some have found PAHs to be occurring in street dust (Obiri et al. 2011;Bandowe and Nkansah 2016), agricultural soils (Nieuwoudt et al. 2011;Ipeaiyeda et al. 2015;Anietie and Godwin 2015), surface water, and sediments of water bodies (Amoako et al. 2010;Kouakou et al. 2015;Botwe 2018). PAHs have also been found in aquatic invertebrates (Nwaichi and Ntorgbo 2016;Chukwumalume 2016;Mohammed et al. 2017), smoked fish (Yolande et al. 2014;Ongwech et al. 2013;Tongo et al. 2017b), smoked or roasted meat, and other food items (Owor et al. 2012;Abdallah 2013;Aderibigbe et al. 2017). ...
... An analysis of 27 sediment samples from nine locations of the river was conducted for the occurrence and levels of PAHs. The results indicated a total of 16 PAH concentrations ranging from 13,000 to 80,000 μg/L in the Densu River, with a mean value of 37,000 μg/L (Amoako et al. 2010). ...
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In the African continent, several studies have been conducted to determine PAH pollution levels with their associated health risks in the environment. However, these studies are very much disconnected. The objective of this study is to conduct a systematic review that serves as a comprehensive report on the PAH-related studies conducted in the African continent. Data sources are from Google Scholar and PubMed. English language studies that reported on PAH levels in smoked fish and meat, soils and dust, aquatic environments, indoor and outdoor air, and ready-to-eat food items were selected. Specific PAHs included the following: 33 PAHs comprising of the 16 USEPA PAHs, non-alkylated PAHs, non-alkylated PAHs, oxygenated PAHs (OPAHs), and azaarenes (AZAs). Study appraisal and synthesis methods: The Newcastle–Ottawa Scale (NOS) was adapted to assess the quality of the selected studies basing on their sampling methods, analytical techniques, and results. A total of 121 studies were reviewed, with the majority (56) being from Nigeria. PAH levels in smoked fish and meat, soils and dust, aquatic environments, indoor and outdoor air, and ready-to-eat food items recorded total concentrations of PAHs ranging from 5 to 3585 μg/kg, BDL to 6,950,000 μg/kg, 0 to 10,469,000 μg/kg, 0 to 7.82 ± 0.85 μg/m3, and 2.5 to 7889 ± 730 μg/kg respectively. Carcinogenic risk assessment for children and adults ranged from very low to very high levels when compared to the ILCR range (10−6 to 10−4) defined by the USEPA. Out of 54 African countries, only 19 were represented. The majority of selected studies failed to apply any standard protocols for sample collection and analysis. The low to very high PAH levels reported in studies calls for effective actions on environmental health. Similar systematic reviews are expected to be performed in other continents for a global assessment of PAH pollution.
... The loadings are further enhanced through atmospheric precipitation. Higher concentrations of PAHs and its alkyl derivatives (total of 51 types) have been reported from various rivers/river basins across the globe like Fraser, Luanhe, Densu, Missouri, Anacostia, Ebro, Delaware, etc. (Yunker et al., 2002;Motelay-Massei et al., 2006;Li et al., 2010;Amoako et al., 2011;Kim et al., 2018). Naphthalene and phenanthrene are found to be the most predominant (detected in 70% of the samples) in the sediments of the Ganga River basin (Duttagupta et al., 2019). ...
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Low molecular weight polycyclic aromatic hydrocarbons (PAHs) like naphthalene and substituted naphthalenes (methylnaphthalene, naphthoic acids, 1-naphthyl N -methylcarbamate, etc.) are used in various industries and exhibit genotoxic, mutagenic, and/or carcinogenic effects on living organisms. These synthetic organic compounds (SOCs) or xenobiotics are considered as priority pollutants that pose a critical environmental and public health concern worldwide. The extent of anthropogenic activities like emissions from coal gasification, petroleum refining, motor vehicle exhaust, and agricultural applications determine the concentration, fate, and transport of these ubiquitous and recalcitrant compounds. Besides physicochemical methods for cleanup/removal, a green and eco-friendly technology like bioremediation, using microbes with the ability to degrade SOCs completely or convert to non-toxic by-products, has been a safe, cost-effective, and promising alternative. Various bacterial species from soil flora belonging to Proteobacteria ( Pseudomonas , Pseudoxanthomonas , Comamonas , Burkholderia , and Novosphingobium ), Firmicutes ( Bacillus and Paenibacillus ), and Actinobacteria ( Rhodococcus and Arthrobacter ) displayed the ability to degrade various SOCs. Metabolic studies, genomic and metagenomics analyses have aided our understanding of the catabolic complexity and diversity present in these simple life forms which can be further applied for efficient biodegradation. The prolonged persistence of PAHs has led to the evolution of new degradative phenotypes through horizontal gene transfer using genetic elements like plasmids, transposons, phages, genomic islands, and integrative conjugative elements. Systems biology and genetic engineering of either specific isolates or mock community (consortia) might achieve complete, rapid, and efficient bioremediation of these PAHs through synergistic actions. In this review, we highlight various metabolic routes and diversity, genetic makeup and diversity, and cellular responses/adaptations by naphthalene and substituted naphthalene-degrading bacteria. This will provide insights into the ecological aspects of field application and strain optimization for efficient bioremediation.
... ng/L) as those in glaciers on the Tibetan Plateau , but lower than the reported concentrations of ΣPAH in the Three Gorges Reservoir (41.5 ng/L) which was influenced by anthropogenic activities extensively (Lin et al. 2018). The 16 PAHs can be divided into three groups: (2 + 3)ring, 4-ring, and (5 + 6)-ring components based on the number of rings, which represent low-, medium-and high-molecularweight PAHs, respectively (Amoako et al. 2011). In the Table 3 Pearson's correlation coefficient matrices for hydrochemical parameters, ΣPAH, ΣPAE, and metals in the water of Lake Bangong Co analysis results of the 16 PAHs in the water samples from the 6 sampling sites, only 12 PAHs were detected. ...
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Lake Bangong Co is a special lake in western Tibet, with characteristics of increased salinity from the eastern area to the western area. Due to its remote location and poor environmental conditions, there are few background data on the water environment of this lake. In this study, the water chemical composition of Lake Bangong Co was studied, and the concentration levels, distribution characteristics, and pollution sources of polycyclic aromatic hydrocarbons (PAHs), phthalic acid esters (PAEs), and metals (As, Pb, Cr, Mn, Cu, Cd, Ni, and Zn) were investigated. The hydrochemical characteristics of the lake showed significant spatial differences. Conductivity, salinity, degree of mineralization, total hardness, Cl⁻, and SO4²⁻ generally increased from the eastern part to the western part. Most water quality parameters met the class III standards of the Chinese surface water standards; however, the Cl⁻ and SO4²⁻ concentrations in the western part exceeded the surface water standard limits. ΣPAH and ΣPAE concentrations in lake water have no significant relationship with hydrochemical parameters. Among the 16 target PAHs, 4 PAH monomers with a (5 + 6)-ring were not detected in the lake water. The main sources of PAHs included emissions from biomass combustion, petroleum volatilization, and automobile exhaust. Six PAE monomers were detected at all sampling sites with relatively low concentrations, and di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP) were the main pollutants. The main source of PAEs was domestic waste, which might be related to increasing human activities in this area recently. In general, the concentrations of metals in the water of Lake Bangong Co were lower than those in the regions affected by anthropogenic activities except As. The results of PCA showed that As, Cu, and Cr mainly originated from natural sources; Pb, Mn, and Cr came from both natural and anthropogenic sources; and Cd was highly likely from anthropogenic sources.
This study investigated twenty-three polycyclic aromatic hydrocarbons (PAHs) in the sediment of Osun River, spanning through both the peri-urban and urban areas of the river, to estimating their sources, ecological and health hazards. The sampling locations covered those beside major roads and agricultural farms. They were analyzed by gas chromatography-mass spectrometry. The concentrations of the PAHs ranged 88–1900 ng/g (average, 731 ng/g) with the predominance (56%) of benzo(e)pyrene (BeP). Though the PAHs had a similar trend of distribution in the sediment at both peri-urban and urban portions, total PAHs concentration at the peri-urban area was three times higher than that obtained in the urban area of the river due to relatively lower photo-degradation process caused by the thick rain forest in the area. Pyrolytic processes such as coal/wood burnings and emissions from gasoline and diesel engines were the PAHs sources. No dermal carcinogenic or non-carcinogenic health concerns were posed by the individual PAH; cancer risk and hazard quotient values were <10⁻⁶ and <1.0, respectively. The sediment PAHs posed a low ecological risk in all the sampling locations as the mean effects range-median quotient of the individual USEPA priority PAHs was ≤0.04. The potential environmental toxicity of the priority PAHs showed that benzo(a)pyrene (BaP) and indeno[1,2,3-cd]pyrene (IDcdP) dominated, accounting for 37% and 44% of the total toxicity, respectively. The low health and ecological risks posed by the PAHs sediment became significant given the number of tourists Osun River attracts annually festival, as well as the effects on the river ecosystem.
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La Biorremediación es el conjunto de procesos biotecnológicos es el conjunto de procesos biotecnológicos que utiliza microorganismos para recuperar el ambiente que ha sido alterado por un contaminante. En los espacios marinos costeros se desarrollan diversas operaciones petroleras que pueden provocar derrames de crudo y sus derivados en los cuerpos de agua los cuales requieren su remoción, en especial los Hidrocarburos Aromáticos Policíclicos (HAPs) esto es posible mediante técnicas modernas de biorremediación. Este libro muestra un prospecto de Micorremediación usando hongos del género Aspergillus lo cual se ha demostrado que pueden remover de 85,9% a un 100% de los HAPs del agua autóctonos de la Bahía de A muay
The interaction mechanisms of chrysene with bovine serum albumin (BSA) were studied by multispectroscopy and molecular docking method. The quenching mechanism, binding constants, thermodynamic parameters and binding force of chrysene with BSA were investigated. The results indicated that the fluorescence of BSA was quenched by chrysene through a static quenching procedure. The binding constants Kb and number of binding sites n were 3.97 × 10⁴ M–1 and 1.0 at 298 K, respectively, which indicated that the binding of chrysene and BSA was moderate and there was one main binding site in BSA for chrysene. The thermodynamic parameters including entropy change (ΔH) and enthalpy change (ΔS) were 40.2 kJ mol–1 and 223.0 J mol–1 K–1, respectively, which revealed that the main binding force of chrysene to BSA was hydrophobic interaction. This result was in accordance with the results from the molecular docking. The binding distance r was 2.60 nm, which suggested that the energy transfer from BSA to chrysene occurred with high possibility. The results of synchronous fluorescence spectra, three-dimensional fluorescence spectra and circular dichroism spectra indicated that the binding of chrysene to BSA induced conformation changes of BSA.
Background: Polycyclic aromatic hydrocarbons (PAH) are considered to be one of the major contaminants of drinking water and natural water bodies. Some of the well documented polycyclic aromatic hydrocarbons that are water pollutants and were considered for analysis in this study included benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), benzo[g,h,i]perylene (BgP), and indeno[1,2,3-c,d]pyrene (InD). This study aimed at determining the levels of concentrations of basically five polycyclic aromatic hydrocarbons in 57 drinking water bodies located around Samsun, Ordu, Giresun, Çorum, Amasya, Kastamonu and Sinop provinces. Materials and method: In this study, the Environmental Protection Agency (EPA) method 550.1 for the determination of polycyclic aromatic hydrocarbons in drinking by Liquid-Solid Extraction (LSE) and High Performance Liquid Chromatography (HPLC) with Coupled Ultraviolet (CD) and Fluorescence Detection (FD) was used. Sampling procedures were done according to the validated method specified by the Turkish Ministry of Enivironment and Forestry. Prior to the determination of concentrations by HPLC, PAHs contained in the samples were separated from the solid phase by Solid-Phase Extraction (SPE). All data analyses were conducted using SPSS and Excel. Results: Obtained results from the investigation revealed that the average total PAH and benzo[a]pyrene (BaP) concentration levels in drinking water samples taken from the central districts of Samsun were 2.73 ± 1.51 and 0.35 ± 0.24 ng/L respectively. In drinking water samples taken from Ordu, Giresun, Çorum, Amasya, Kastamonu and Sinop, the average total PAH concentrations were found to be 5.85 ± 3.82 ng/L, 3.79 ± 1.27 ng/L, 1.08 ± 0.62 ng/L, 2.42 ± 1.04 ng/L; 1.92 ± 0.35 ng/L and 4.07 ± 2.33 ng/L respectively. The average (BaP) concentrations for the same named locations were determined as 0.97 ± 0.75 ng/L; 0.55 ± 0.29 ng/L; 0.11 ± 0.08 ng/L; 0.35 ± 0.10 ng/L; 0.14 ± 0.04 ng/L; 0.39 ± 0.23 ng/L, respectively. It is therefore evident that the values of PAH and BaP in drinking water were below the limits of 100 and 10 ng/L specified in the Regulation on Water Intended for Human Consumption. These values are below the set limits proposed by Turkish legislation and WHO. Conclusion: All the results for drinking water, usable water and natural spring water were below the values specified in the Regulation on Water Intended for Human Consumption and WHO. The PAH content of the studied river waters as well were below the limits proposed by Turkish legislation and WHO.
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Las operaciones petroleras pueden provocar derrames de crudo y sus derivados sobre los cuerpos de agua los cuales requieren su remoción, en especial la fracción de los Hidrocarburos Policíclicos Aromáticos (HPA), dado que son el grupo con mayores efectos negativos sobre el ambiente y salud humana, este hecho es común en puertos petroleros como La Bahía de Amuay, motivo por el cual seevaluó la remoción de HPA mediante, los parámetros físico-químicos del aguapH, conductividad eléctrica, temperatura, cloruros, fósforo total, nitrógeno, oxígeno disuelto, aceites y grasas que presentaron valores normales dentro de la normativa nacional. La caracterización e identificación de 3 cepas dos de Aspergillus flavus y una Aspergillus niger, que fueron sometidas a un ensayo de factibilidad seleccionando la cepa de Aspergillus niger como la cepa con mayor capacidad de remoción de HPA.Esta cepa fue utilizada en un ensayo de tratabilidad donde fue posible obtener un máximo de remoción 85,9 %
The interaction between chrysene with humic acids (HA) was studied by the fluorescence spectroscopy. The results of fluorescence spectra revealed that chrysene could strongly quench the intrinsic fluorescence of HA through a static quenching procedure. The apparent binding constants K and number of binding sites n of chrysene with HA were 2.99 × 10⁵ and 1.0 which were obtained by the fluorescence quenching method. The thermodynamic parameters enthalpy change (ΔH), entropy change (ΔS) were negative, which indicated that the interaction of chrysene with HA was driven mainly by van der Waals forces and hydrogen bonds. The process of interaction was a spontaneous process in which Gibbs free energy change was negative. The results of three-dimensional fluorescence spectra showed that the chrysene entered into the hydrophobic cavities in some domain of HA.
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Water quality assessment conducted in the Densu basin of Ghana between July 2003 and March 2004 identified human, animal and agricultural activities as the main sources of pollution. The pH of the water was neutral (pH range 7.20–7.48) and was unaffected by seasonal variation. The river waters were moderately soft to slightly hard (range of hardness 91.2–111 mg/l CaCO 3) with high turbidity due to poor farming practices, which result in large quantities of topsoil ending up in the river after rains. High nutrient loads observed in the basin were due to domestic, agricultural and industrial activities. The waters exhibited a general ionic dominance pattern of Na > Ca > Mg > K and HCO 3 > Cl > SO 4 , a pattern which is an intermediate between fresh and sea water systems. The dominance of chloride over sulphate could probably be due to domestic activities resulting from household effluents, fertilizer use and other anthropogenic point sources. Trace metal levels were low suggesting low metal contamination of the river. However, the microbial quality of the river water was poor due to direct contamination by animal and human excreta and other activities such as swimming, washing of clothes, etc. The river water cannot be used for domestic purposes without any form of treatment.
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The concentration of 13 PAHs in groundwater was measured at 12 locations of Agra. The mean concentration of TPAH in all samples was 31.86 ng L<sup align="right"> −1 </sup> and it ranges from 13.2 ng L<sup align="right"> −1 </sup> to 64.3 ng L<sup align="right"> −1 </sup>. The 4-ring and 5-ring PAHs were found to be dominant in the groundwater of Agra region having 38.6% and 26.4% of the TPAH. The carcinogenic potency was estimated and it was found 2.7 ng L<sup align="right"> −1 </sup>. Univariate Pearson correlation matrix shows a good correlation among all PAHs except B(a)P. The levels of PAHs in the groundwater can help in environment risk assessment of this area.
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Polar and nonpolar fractions prepared from an organic extract of inhalable air particulate material collected from an urban location in downtown Toronto, Ontario, Canada, were examined for estrogen and Ah receptor-mediated activities using in vitro gene expression assays. The presence of estrogenic activity was determined using MCF-7 human breast cancer cells transiently transfected with a Gal4-human estrogen receptor chimera and a Gal4-regulated luciferase reporter gene. 2,3,7,8-Tetracholordibenzo-p-dioxin (TCDD)-like activity was detected using Hepa 1c1c7 cells transiently transfected with a CYP1A1-regulated reporter gene (pGudLuc 1.1). Significant estrogenic and TCDD-like activity was detected in the crude extract and in the nonpolar fractions. Results from the analyses of nine environmentally prevalent polyaromatic hydrocarbons (PAH) indicated that PAH might be significant contributors to the observed activity. Surprisingly, three PAH, namely benzo[a]pyrene, chrysene, and benz[a]anthracene, were found to substantially induce in vitro estrogenic and TCDD-like activities that were mediated by the estrogen and Ah receptors, respectively. Benzo[k]fluoranthene, dibenz[a,h]anthracene, and anthracene also exhibited significant in vitro TCDD-like activity. These results demonstrate the utility of in vitro gene expression assays to identify the presence of potential endocrine disruptors within complex mixtures.
In order to determine the origin of polycyclic aromatic hydrocarbons (PAHs) in sediments from Narragansett Bay, Rhode Island, the PAH assemblages from the sediments and from possible origin materials were analyzed by gas Chromatographic and gas chromatographic-mass spectrometric techniques. Analyses included determinations of: 1. (1) the relative content of non-alkylated PAH parent molecules i.e. parent compound distributions (PCDs); 2. (2) alkylation patterns of these PAH molecules, i.e. alkyl homolog distributions (AHDs); and 3. (3) phenanthrene/anthracene (P/A) ratios. Samples from the Narragansett Bay transect, which began at a sewage outfall for the City of East Providence, Rhode Island, and ended 20 km to the south, showed rapidly decreasing concentrations of PAH compounds with increasing distance from Providence. The PAH assemblages in transect sediment samples, and in other samples collected near piers, showed evidence for different origins. The sediments surrounding tarred piers were contaminated by coal tar used to coat the pilings. The close resemblance of PCDs from bay sediments and combustion products indicated that the PAHs in the transect sediments were predominantly combustion generated. While evidence for the input of PAHs from petroleum to bay sediments appeared in some AHDs of upper bay transect sediments, AHDs from the lower (less polluted) end of the transect showed less influence of petroleum PAH contamination. In general, the shapes of AHDs from transect sediments of Narragansett Bay appeared to be best explained by a combination of inputs of PAHs from petroleum and combustion processes, rather than by the solubility alteration of PAH assemblages on incoming airborne material.
This work deals with 48 substances composed exclusively of unsubstituted six-membered fused aromatic rings. In the first step, physicochemical properties which are relevant in environmental studies such as the boiling temperature (Tb), the retention index (RI), n-octanol/water partition coefficient (KOW) and solubility (S) are related with a series of electronic, geometric and topological descriptors. Among them are: electron affinity, the difference between electron affinity and ionization potential (GAP), Wiener, and connectivity indexes, volume, surface area, length-to-breadth ratio and enthalpy of formation. In a second step, these properties were incorporated into the descriptor matrix to build several quantitative structure–property relationships and to obtain prediction rules for the logKOC, logKOA, bioconcentration factor (BCF) and Henry’s law constant (H). Finally, the photo-induced toxicity of freshwater organism Daphinia-Magna is modeled using the following transformed electronic descriptors: electron affinity, ionization potential and Gap.
The objective of this study was set out to assess the exposure levels of both polycyclic aromatic hydrocarbons (PAHs) and their corresponding carcinogenic potencies for highway toll station workers associated with vehicle emissions. We collected 48, 35, and 33 personal PAH samples from booth attendants of the dayshift (08:00AM−16:00PM), nightshift (16:00PM−00:00AM), and late-nightshift (00:00AM−08:00AM), respectively. We found no significant difference in PAH homologue distributions among the workers’ exposure profiles of the three work shifts. Both total-PAH and total-BaPeq exposure levels for dayshift workers (=12,300 and 230ng/m3, respectively) were not significantly different from that for nightshift workers (=11,500 and 203ng/m3, respectively), but both were significantly higher than that for late-nightshift workers (=8280 and 151ng/m3, respectively). We conducted multivariate linear regression analyses to relate booth attendants’ exposure levels to the involved vehicle flow rates and environmental factors. We found none of the three environmental factors (i.e., wind speed, humidity and air temperature) was significant. On the other hand, we found the vehicle flow rate was able to explain 76% and 62% variations of booth attendants’ total-PAH and total-BaPeq exposures, respectively. Considering measuring vehicle flow rate is much less labor consuming and costly than direct measuring PAHs, the above regression results can be regarded, at least, as a useful indirect approach for estimating the booth attendants’ exposure levels.
Polycyclic aromatic hydrocarbons (PAH) emitted from fluidized bed combustion have been reviewed. Firstly, the PAH origin is undertaken. Secondly, the state of the art on their sampling and analytical procedures are commented. Finally, the influence of the fuel, fossil and nonfossil fuels, the combustor type and the combustion variables are analyzed concerning PAH formation and emission in solid/gaseous phase.