Exposure of the Roots of <Emphasis Type="Italic">Populus nigra</Emphasis> L. cv. Loenen to PAHs and its Effect on growth and water balance

Poplar cuttings were cultivated for 4 weeks in a substrate, which consisted of a combination of sand and nutrient solution. The plants were treated for 24 days with BaP, Chr, Ant, Phen, P and Flt, single or in combination. The concentration of the PAHs ranged from 0.1-200 mg/kg substrate. The results of the pollution experiments can be summarized as follows: 1. The most significant deviations between the test groups and the control can be observed for transpiration, nutrient solution uptake, and root mass. 2. Although transpiration and nutrient solution uptake are significantly lower for all the treated groups than for the control group, the water content of the leaves was not affected by PAHs. 3. The biomass of the shoots and the growth in shoot length do not react as strongly to exposure to PAHs as transpiration, nutrient solution uptake and the volume of the roots. 4. The differences in leaf weight and leaf surface area are significantly less pronounced compared to the control groups. Growth inhibition is most evident with Flt. Growth and absorption of the nutrient solution dropped with just Flt 0.1 mg/kg substrate. When the substrate concentration was increased, growth and nutrient solution uptake dropped considerably and at a concentration of Flt 200, 5 of the 11 test plants died before the end of the period of exposure. Nutrient solution uptake and shoot development of the test plants decreased in the following order: BaP H approximately = Chr > Ant > Phen > Pyr > Flt.     

Aquatic predicted no-effect concentration for three polycyclic aromatic hydrocarbons and probabilistic ecological risk assessment in Liaodong Bay of the Bohai Sea, China

Predicted no-effect concentration (PNEC) is often used in ecological risk assessment to determine low-risk concentrations for chemicals. In the present study, native marine species were selected for toxicity testing. The PNECs for three polycyclic aromatic hydrocarbons (PAHs), specifically phenanthrene (Phe), pyrene (Pyr), and benzo[a]pyrene (BaP), were derived from chronic and acute toxicity data with log-normal statistical methods. The achieved PNECs for Phe, Pyr, and BaP were 2.33, 1.09, and 0.011 μg/L, respectively. In Jinzhou Bay and the Shuangtaizi River Estuary of Liaodong Bay in the Bohai Sea, China, the surface water concentrations of the three PAHs were analyzed by gas chromatography–mass spectrometry. Based on two probabilistic ecological risk assessment (PERA) methods, namely probabilistic risk quotient and joint probability curve, the potential risk of Phe, Pyr, and BaP in Jinzhou Bay and Shuangtaizi River Estuary was assessed. The same order of ecological risk (BaP > Phe > Pyr) was found by both models. Our study considered regional characteristics of marine biota during the calculation of PNECs, and the PERA methods provided probabilities of potential ecological risks of chemicals. Within the study area, further research on BaP is required due to its high potential ecological risk.     

Polycyclic aromatic hydrocarbons in the surface soils from outskirts of Beijing, China

Surface soils from the outskirts of Beijing were analyzed for 16 priority polycyclic aromatic hydrocarbons (PAHs) using gas chromatography and mass spectrometry (GC-MS). The distribution map of total PAHs content was obtained as a contour plot. The concentration range of 16 PAHs varied by over two orders of magnitude from 0.016 microg g-1 in rural to 3.884 microg g-1 in suburban soils with the relatively standard deviation of 70.5%, showing large differences in the extent of PAHs pollution at the various sampling sites. It was notable that the concentration of BaP was 0.005-0.270 microg g-1 with a mean of 0.055 microg g-1. In general, the distribution of PAHs centered on the high molecular weight PAHs known to be carcinogenic. The 4-6 ring PAHs represented about 66% in rural samples and 70% in suburban soils of the total PAHs found. There was relatively good relationship among most of the individual PAHs and the compounds of Pyr, BaA, Flu, BbF, BaP, Chr and Ph gave strong correlation (r>0.8) with the sum of PAHs. The selected marked compounds, a principal component analysis (PCA) and special PAHs compound ratios (Ph/An vs Flu/Pyr; summation operator COMB/ summation operator EPA-PAHs) suggest the pyrogenic origins, especially traffic exhausts, are the dominant sources of PAHs in Beijing outskirts soils.     

Polycyclic aromatic hydrocarbons in soils in the vicinity of Nanjing, China

The occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) in vegetable soils from five vegetable fields (including: Liuhe, Xixia, Pukou, Jianye and Yuhua districts) in Nanjing outskirt were investigated with high performance liquid chromatography (HPLC) equipped with fluorescence detector. The total concentrations of 15 priority PAHs in 126 soil samples ranged from 21.91 to 533.84ngg(-1) dry weight, and the sum of seven carcinogenic PAHs concentrations varied from 1.48 to 236.19ngg(-1) dry weight. Statistical analysis of the PAHs concentrations showed that the highest PAHs concentration was observed in Liuhe, and the lowest PAHs concentrations were found in Xixia among the five districts. The ratios of fluoranthene to sum of fluoranthene and pyrene concentrations (Flt/(Flt+Pyr)) were more than 0.5 in 99% of vegetable soil samples, showing that the PAHs in soils were generally derived from straw and coal combustion sources. The results from principal component analysis (PCA) further indicated that extensive combustion activities affected the PAHs distribution in Nanjing vegetable soils.     

In vitro EROD induction equivalency factors for the 10 PAHs generally monitored in risk assessment studies in The Netherlands

The ethoxy resorufin dealkylase (EROD) inducing potency of 10 polycyclic aromatic hydrocarbons (PAHs) is measured in the H4IIE in vitro bioassay and the results are compared to those reported in literature. The selected PAHs varied considerably in their potency to induce EROD activity. Anthracene (Ant) and phenanthrene (Phe) showed consistently no response. Naphthalene (Nap) showed no or a very weak response on EROD activity. Fluoranthene (Fla) and benzo[g,h,i]perylene (BghiP) showed weak responses at the highest doses. The other PAHs, including indeno[1,2,3-cd]pyrene (IP), benz[a]anthracene (BaA), benzo[a]pyrene (BaP), chrysene (Chr) and benzo[k]fluoranthene (BkF), showed full bell shaped dose-response curves. BaP EROD induction equivalency factors (BaP-1EF) were calculated and increased in the order Ant approximately Phe < Fla < Nap < BghiP < IP < BaA < BaP < Chr < BkF. Comparison of BaP-IEFs based on 50% effect concentration (EC50) or lowest effect concentration (LEC), yielded a significant relationship between both methods described by the equation log(BaPIEF(EC50) = 0.55 x log(BaPIEF(LEC)) + 0.07 (r2 = 0.913). BaP-IEFs as derived from our measurements and as reported in literature and measured in other in vitro assays deviated up to a factor of 17 among the different studies, but the potency rankings were comparable. For the PAH mixture as on average present in the human diet an overall tetrachlorodibenzo-p-dioxin (TCDD)-IEF of 1 x 10(-4) was estimated. The total PAH based TCDD induction equivalents (IEQ) intake then was calculated 300 pg/day, which is approximately 2 times higher then the PHAH based TCDD-EQ intake reported for humans.     

Risk of polycyclic aromatic hydrocarbon (PAH) exposure from ingested food: the Azerbaijan case study

Risks due to polycyclic aromatic hydrocarbons (PAHs) exposure from food consumption for the population of Azerbaijan were determined using deterministic and probabilistic methods. The guidelines and methods described and presented in the United States Environmental Protection Agency (U.S. EPA) Risk Assessment Guidance for Superfund (RAGS) Part A was used in performing the risk assessments. The current study utilized concentration data from different sources representing international studies performed over the past decade to determine those food products that contribute the most exposure to PAHs through ingestion for the Azeri population. Due to lack of concentration data from middle-Eastern countries, only European countries were considered and used for this analysis. Using the benzo[a]pyrene (BaP) toxicity equivalency factors (TEFs) to adjust the concentrations of the individual PAH compounds to BaP equivalent concentrations, risk analyses were performed. Deterministic risk estimates fell within probabilistic risk estimates. Child risks were consistently four to seven times higher in magnitude than adult risks. Risk potentials determined for the food exposure pathway were also determined to be up to ten times higher in magnitude than risks determined from exposures due to other pathways such as soil contamination. It was observed that three major factors contributed to the variability in the assessment results, which were child and adult body weights, consumption rates of the different food groups, and the variances of the input data. The most prevalent pathways of PAH exposure from the dietary patterns of the Azerbaijani population were determined to be from bread and bakery products, milk and dairy products, and egg products.     

Molecular evidence for benzo[a]pyrene and naphthalene genotoxicity in Trifolium repens L

Polycyclic aromatic hydrocarbons (PAHs) are among the most dangerous environmental contaminants due to their toxic, carcinogenic and mutagenic effects. Although there are many data in literature that detail the effects of PAHs on animals, little is known about their action on higher plants which are often used as bioindicators. The aim of the present study was to evaluate the genotoxicity of two different PAHs, benzo[a]pyrene (BaP) and naphthalene (Naph), on Trifolium repens L. Clover plants were exposed to soil which had been artificially contaminated with three concentrations of BaP (5, 10 and 20 microg g-1) or Naph (25, 50 and 100 microg g-1). After 15 days, changes in the DNA content and sequence of roots and shoots were evaluated by flow cytometry (FCM) and amplified fragment length polymorphism (AFLP). Root and shoot dry weight were also determined to assess plant growth. Results showed that BaP and Naph were both genotoxic for white clover, inducing significant changes in root and shoot DNA sequence. Damage was more severe in the root than in the shoot suggesting that the translocation of these compounds and their genotoxic metabolites was limited. Ploidy alterations were not detected and the extent of damage caused by all the tested PAH concentrations was not sufficient to affect plant development.     

Assessing contamination of smoked sprats (Sprattus sprattus) with polycyclic aromatic hydrocarbons (PAHs) and changes in its level during storage in various types of packaging

The analysis of material used in this study demonstrated that the amount of polycyclic aromatic hydrocarbons (PAHs) in smoked sprats varies from the level below the lowest detection limit in muscles up to 9.99 µg kg^?1 of benzo[a]pyrene (BaP) in fish skin. Such a high level of PAHs in skin was reported only in one of six batches of sprats, while mean BaP level was at 1.69 µg kg^?1. Regardless such a high BaP level in skin, its concentration in muscles did not exceed the maximum acceptable level. The study objective was to assess to what extent packaging materials adsorb PAH compounds from food. Changes in the PAH levels were monitored in fish during their storage in packages made of various materials. The storage time was from 0 to 168 hours. The obtained results varied considerably, therefore their scatter did not allow to confirm unequivocally the preliminary hypothesis about the reduction of PAHs due to their migration to packaging material. However, analysis of the packaging used in this study demonstrated a significant increase in the level of total 16 PAHs. When high-density polyethylene (HDPE) packaging was analysed, a six-fold increase in the total 16 PAHs was observed comparing to the blank sample.     

Comparison of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons in airborne particulates collected in downtown and suburban Kanazawa,Japan

In this study, airborne particulates were collected at three sites, two in a downtown area and the other in a suburban area of Kanazawa, Japan in each season for 7 years. Two polycyclic aromatic hydrocarbons (PAHs), pyrene (Py) and benzo[a]pyrene (BaP) and four nitropolycyclic aromatic hydrocarbons (NPAHs), 1-nitropyrene (NP) and 1,3-, 1,6-, and 1,8-dinitropyrenes (DNP) were determined by high-performance liquid chromatography with fluorescence and chemiluminescence detection. At the downtown sites, the mean concentration of each DNP was about two orders of magnitude lower than that of 1-NP and more than three orders of magnitude lower than those of Py and BaP. This tendency reflected the composition of PAHs and NPAHs in diesel-engine exhaust particulates. Concentrations of these PAHs and NPAHs were higher at the downtown sites than at the suburban site, suggesting the dilution of these compounds during the transportation from the downtown to the suburban area. The concentration ratios of NPAHs to PAHs were larger at the downtown sites than at the suburban site. Studies using UV light and sunlight showed that degradation of NPAHs was faster than that of PAHs. Thus, the lower concentrations of NPAHs in the suburban sites may be due to their being photodegraded faster than PAHs during the atmospheric transportation from the downtown area to the suburban area.     

Factors controlling benzo(a)pyrene concentration in aerosols in the urbanized coastal zone. A case study: Gdynia, Poland (Southern Baltic Sea)

Annual study on the benzo(a)pyrene (BaP) concentration in aerosols in the coastal zone of the Gulf of Gdansk (southern Baltic) has been performed at Gdynia station. Combustion processes, especially domestic heating of both local and regional origin, were identified as the main sources of benzo(a)pyrene in this area. Concentrations observed during the heating season (mean 2.18 ng?m^?3) were significantly higher than these recorded in the non-heating season (mean 0.05 ng?m^?3). High benzo(a)pyrene concentrations were associated with low temperature and high humidity. Whereas high levels of precipitation usually decreased the BaP concentration in aerosols. The concentration of this factor in the studied area depended also on the wind direction and air masses trajectories. During heating season, continental air masses (coming from S, SE, SW) seemed to increase benzo(a)pyrene concentration, while maritime air masses (from N, NE, NW) caused its decrease. The differences in the BaP concentration resulting from potentially different emission levels of this compound during working and non-working days were not clearly pronounced.     

The temporal variability of the profile of carcinogenic polycyclic aromatic hydrocarbons in urban air: a study in a medium traffic area in Rome, 1993–1998

The constancy, both temporal and spatial, of the profile of polycyclic aromatic hydrocarbons (PAHs) relative to benzo[a]pyrene (BaP) is a prerequisite to using the BaP-indicator approach in the carcinogenic risk assessment for PAHs. The principal aim of this study was to provide a contribution to validate this approach, by studying the variability of the profile at a typical urban site through a multi-year data set and by comparing the profiles available for different cities. Seven carcinogenic PAHs (benz[a]anthracene, benzo[b+j+k]fluoranthenes, BaP, indeno[1,2,3-cd]pyrene, dibenz[a,h]anthracene) were determined in PM₁₀ 24-h samples collected every third day at a road site; moreover, benzo[e]pyrene was determined as a reference PAH due to its stability. The profile was found stable from year to year. Besides, it was similar to those recently found in other European cities (observed differences within a factor of four) and to those elaborated from earlier (1970s–1980s) investigations. The substantial similarity of profiles, both temporal (on an annual basis) and spatial, supports the validity of the BaP-indicator approach. Large PAH-to-PAH differences were, however, found in the seasonal pattern of profile: they were explained by the different atmospheric degradability of PAHs, whose effect is enhanced under the meteoclimatic conditions typical of the European Mediterranean countries. PAH annual means showed a slight declining trend since 1994. In the last sampling year, mean concentration of BaP was 1.2 ng m⁻³. Within-year differences among monthly averaged PAH concentrations were observed, as large as up to 44-fold for BaP, underlining the need for whole-year monitoring.     

Responses of antioxidant systems and LPO level to benzo(a)pyrene and benzo(k)fluoranthene in the haemolymph of the scallop Chlamys ferrari

The effects of benzo(a)pyrene (BaP), benzo(k)fluoranthene (BkF) and their mixture on antioxidant enzyme activities and lipid peroxidation (LPO) levels of haemolymph of scallop (Chlamys ferrari) were studied. The superoxide dismutase (SOD) activities of 0.5 microg/L and 1.0 microg/L were significantly higher than controls (P<0.05), while it increased at beginning and then dropped (lower than controls) in the end at 10.0 microg/L and 50.0 microg/L PAHs groups. The catalase (CAT) activities were very little during the whole experimental time. The glutathione peroxidase (GPx) activities in each PAHs group all increased significantly (P<0.05). LPO levels all increased significantly (P<0.05) with time at each PAHs group except for the 0.5 microg/L group of less than hour 12. The toxicity of PAHs in a descending order was BaP>BkF>mixture of BaP and BkF. The changes in antioxidant enzyme activities and LPO level in haemolymph could reflect the detoxification functions and damage levels of whole organism.     

Uptake of polycyclic aromatic hydrocarbons (PAHs) in salt marsh plants Spartina alterniflora grown in contaminated sediments

Polycyclic aromatic hydrocarbon (PAH) concentrations were measured in Spartina alterniflora plants grown in pots of contaminated sediment, plants grown in native sediment at a marsh contaminated with up to 900 microg/g total PAHs, and from plants grown in uncontaminated control sediment. The roots and leaves of the plants were separated, cleaned, and analyzed for PAHs. PAH compounds were detected at up to 43 microg/g dry weight in the root tissue of plants grown in pots of contaminated soil. PAH compounds were detected at up to 0.2 microg/g in the leaves of plants grown in pots of contaminated soil. Concentrations less than 0.004 microg/g were detected in the leaves of plants grown at a reference site. Root concentration factor (RCF) values ranged from 0.009 to 0.97 in the potted plants, and from 0.004 to 0.31 at the contaminated marsh site. Stem concentration factor (SCF) values ranged from 0.00004 to 0.03 in the potted plants and 0.0002 to 0.04 at the contaminated marsh. No correlation was found between the RCF value and PAH compound or chemical properties such as logKOW. SCF values were higher for the lighter PAHs in the potted plants, but not in the plants collected from the contaminated marsh. PAH concentrations in the roots of the potted plants are strongly correlated with soil concentrations, but there is less correlation for the roots grown in natural sediments. Additional plants were grown directly in PAH-contaminated water and analyzed for alkylated PAH homologs. No difference was found in leaf PAH concentrations between plants grown in contaminated water and control plants.     

Studies on polycyclic aromatic hydrocarbons in two sediment cores from the huaxi reservoir,china: Assessment of levels,sources, and ecological risk

This study investigated the levels, sources and ecological risks of 16 polycyclic aromatic hydrocarbons (PAHs) in two sediment cores that were collected along the Huaxi Reservoir. The spatial distributions and residue levels of the 16 priority PAHs in the sediments from the Huaxi Reservoir were analyzed for their potential ecological risk, source apportionment and contribution to the total PAH residue. The concentration level of the total PAHs (TPAHs) was in the range 1805 ng·g^?1 to 20023 ng·g^?1 based on dry weight, and the content of PAHs in the Huaxi Reservoir exhibited a gradual upward trend. The PAH congener ratios fluoranthene/(fluoranthene + pyrene) and indeno[1, 2, 3-cd]pyrene/(indeno[1, 2, 3-cd]pyrene + benzo[g, h, i]perylene) were used to identify the source. The main source of the low molecular weight PAHs was wood and coal combustion, whereas the high molecular weight PAHs were primarily from petroleum combustion sources. The results of an ecological risk assessment demonstrated that ACE poses a potential ecological risk, while FLU, NAP, ANT, BaP, DBA, PHEN and PYR can have serious ecological risks.     

添加剂对堆肥降解多环芳烃的影响

为了研究多环芳烃(PAHs)污染土壤堆肥修复的加速机制,在人工控温的堆肥装置中以芘、菲和芴为研究对象,采用室内模拟实验的方式研究了添加硫酸钙、过磷酸钙、草炭、竹炭、十二烷基硫酸钠(K12)和十二烷基苯磺酸钠(SD-BS)等对锯末高温堆肥降解污染土壤PAHs的影响。研究结果表明,生物堆肥可以有效的去除土壤中PAHs,堆肥7周后所有处理下芘、菲和芴的降解率基本达到80%以上。不同添加剂处理下芘、菲和芴降解率不同,尤其是添加草炭和竹炭处理中芴和菲在第4周的时候就取得90%以上的降解率,芘在第6周也取得80%以上的降解率,而且氮素的损失率也分别下降了42.6%和36.09%,比其他处理的PAHs降解率和保氮效果都要好。分析其原因,一方面可能是添加不同添加剂对堆肥过程中pH值、有机质(SOM)、总氮(TN)和过氧化氢酶(CAT)都有一定的影响,提高了土壤微生物的活性;另一方面可能是由于草炭和竹炭对氨有良好的吸附性,具有良好的保氮效果,同时也能改善了微生物和目标化合物的接触方式,从而提高了PAHs的降解率。     

Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Sediment Cores of Selected Creeks in Delta State,Nigeria

The spatial and seasonal distribution and concentrations of polycyclic aromatic hydrocarbons (PAHs) were investigated in core sediments of Ubeji, Ifie, and Egbokodo creeks in the Niger Delta, Nigeria. A total of 222 core sediment samples were collected during the wet season (August 2010) and the dry season (January 2011). The samples were dried, Soxhlet extracted, fractionated, and injected into a gas chromatograph with flame ionization detector (GC-FID). The concentrations of PAHs ranged from not detected to 2,654 μg/kg (wet season) and not detected to 3,513 μg/kg (dry season). In general, the concentrations of PAHs for a number of stations in this study are comparable to sites with high anthropogenic activities in the Niger Delta. The toxicity risk assessment based on the total BaP equivalent quotient of the seven carcinogenic PAHs (BaA, Chry, BbF, BkF, BaP, DBA, and Iper) was 97.416 μg/kg and did not exceed the method B cleanup level for benzo(a)pyrene (137 μg/kg), according to toxic equivalency factors, which implied that PAHs in sediments of the present study currently have minimal adverse effects. This study provided information on the concentrations and profiles of PAHs sediment cores, which is useful for source diagnosis, environmental quality management, contamination history, and environmental forensic studies.     

Biodegradation of anthracene in the roots and growth substrate of poplar cuttings

Following their exposure to anthracene, the roots of Populus nigra L. Loenen showed traces of 9 substances classed as products of biodegradation. The main substances detected were phthalic acid and 9,10-anthraquinone, followed by hydroxyanthracene and methoxyanthracene and five other compounds which could not be identified. Due to the relatively low concentration of degradation products found in the roots, further degradation to lower molecular compounds are discussed. The presence of 9,10-anthraquinone as the main product of the degradation of anthracene was also evident in the control tests with unplanted sandy substrate, although the content was higher in the planted series of tests. As a non-sterile approach was chosen, it may be assumed that a microbial degradation for 9,10-anthraquinone took place in the control series. However, it is difficult to differentiate clearly between a microbial degradation of anthracene in the substrate and metabolization in the roots due in part to the absence of specific degradation products in the various reaction areas.     

Characterizations of particle-bound trace metals and polycyclic aromatic hydrocarbons (PAHs) within Tibetan tents of south Tibetan Plateau, China

INTRODUCTION: Exposure to trace metals and polycyclic aromatic hydrocarbons (PAHs) adsorbed on particulates is of a serious health concern. Levels of some trace metals in total suspended particulate and 13 PAHs of fine particulate matter were measured from nomadic tents in the southern Tibetan Plateau in summer 2010. RESULTS AND DISCUSSION: The indoor air within the tents was seriously polluted, mainly due to yak dung combustion. Average trace metal concentrations were much higher (range of indoor/outdoor ratio 61-291) than those of the outdoor air. Additionally, enrichment factors of most trace metals of indoor air were similar to those of outdoor air, indicating outdoor air quality of the studied area was possibly influenced by pollutants emitted from local tents. Mean concentrations of total PAHs and BaP within tents was 5372.45 and 364.79 ng/m(3), hundred times higher than that of outdoor air of the Tibetan Plateau. Three- and four-ring PAHs were the predominant components. The diagnostic ratio of BaA/(BaA + Chr) was 0.33. Since Tibetan women typically spend longer time within the tents, they were exposed to PAHs (BaP exposure = 1.81 μg/m(3)) about two times of other family members. Among all the PAHs, Bap contributed the most (82.6%) of the total carcinogenicity. Similarly, the excess lifetime cancer risk for women and other family members were 2.75 × 10(-4) and 1.27 × 10(-4), respectively, indicating Tibetan herdsmen, especially women who are in charge of most house chores were at risk for adverse health effects.     

Atmospheric pollution by PAHs, PCDD/Fs and PCBs simultaneously collected at a regional background site in central Italy and at an urban site in Rome

Concentrations of PAHs and PCDD/Fs were measured throughout one year, and PCBs during the second semester, at a rural site in a natural park representative of background pollution in central Italy; results were compared with simultaneous measurements performed at an urban site in Rome 60km away. Twenty-four daily samples were collected at each site by a high-volume PM(10) sampler from February 2000 to January 2001. After ultrasonic extraction and clean-up by TLC, samples were analysed by GC-MS. Mean concentrations of benzo[a]pyrene (BaP, as a marker of carcinogenic PAHs), summation operatorPCDD/Fs and summation operator64 PCBs in Rome were, respectively: 1.1ngm(-3), 65fgWHO-TEQm(-3), 553pgm(-3). The background concentrations were, respectively: 0.016ngm(-3), 3fgWHO-TEQm(-3), and 94pgm(-3). Hence, BaP, and the other PAHs, showed the highest urban-background gradient (two orders of magnitude) and PCBs the lowest. The background pollution levels of BaP and PCDD/Fs were in agreement with the few available background/remote measurements in Europe. In Rome PAHs and PCBs, but not PCDD/Fs, were clearly seasonal; the PCDD/F TEQ was moderately correlated with BaP (P<0.001). At the background site, the seasonality of PAHs was less marked, while it could not be assessed for PCDD/Fs and PCBs. The PCB TEQ accounted for 4% and 15% of total (PCDD/Fs+PCBs) TEQ at the urban and background site, respectively. Mean PM(10) concentration was 54microgm(-3) in Rome and 15microgm(-3) at the background site.     

Potential sources and meteorological factors affecting PM<Subscript>2.5</Subscript>-bound polycyclic aromatic hydrocarbon levels in six main cities of northeastern Italy: an assessment of the related carcinogenic and mutagenic risks

A yearlong sampling campaign (2012–2013) was conducted in six major cities of the Veneto region to investigate the spatial-temporal trends and the factors affecting the polycyclic aromatic hydrocarbon (PAHs) variations and identify the local sources. Sixty samples per city were collected for analyses in every alternate month (April, June, August, October, December, and February): 10 samples per sampling site in 10 consecutive days of the months selected. Samples were ultrasonically extracted with acetonitrile and processed through high-performance liquid chromatography. Total Σ-PAH concentrations ranged from 0.19 to 70.4 ng m^?3 with a mean concentration of 11.5 ng m^?3. The mean benzo[a]pyrene (BaP) concentration reached 2.0 ng m^?3, which is two-times higher than the limit set by the European Union. BaP contributed for 17.4% to the total concentration of PAHs, which showed the same pattern across the region with maxima during cold months and minima in the warm period. In this study, PAHs showed an inverse relationship with temperature, solar radiation, wind speed, and ozone. According to this study, biomass burning for household heating and cooking, followed by gaseous PAHs absorption on particles due to low atmospheric temperature, were the main reasons for increasing PAHs concentration in winter. Health risk, evaluated as lifetime lung cancer risk (LCR), showed a potential carcinogenic risk from the airborne BaP_TEQ six-fold higher in the cold season than in the warm one. Diagnostic ratios and conditional probability functions were used to locate the sources, and results confirmed that local emission, overall domestic heating, and road transport exhausts were responsible for higher concentration rates of PAHs as well as of PM_2.5.