Benzo[k]fluoranthene Research Articles

Genotoxicity Set Up in Artemia franciscana Nauplii and Adults Exposed to Phenanthrene, Naphthalene, Fluoranthene, and Benzo(k)fluoranthene

Polycyclic aromatic hydrocarbons (PAHs) consist of a group of over 100 different organic compounds mainly generated by anthropogenic activities. Because of their low water solubility, they tend to be accumulated in sediment, where their degradation rate is very low. Few studies have been carried out so far to investigate the effects of PAHs on Artemia franciscana. Artemia is easy to manage at laboratory scale, but it is not a sensitive biological model considering the traditional endpoints (i.e., mortality). In addition to evaluating the lethality on nauplii and adults of A. franciscana after 24 and 48 h, we focused on the genotoxicity to investigate the potential effects of phenanthrene (PHE), naphthalene (NAP), fluoranthene (FLT), and benzo(k)fluoranthene (BkF). Results showed that FLT was the most toxic both for nauplii and adults after 48 h of exposure. Real-time qPCR showed that all toxicants, including BkF, which had no negative effects on the survival of the crustacean, were able to switch the gene expression of all nine genes. This work has important ecological implications, especially on contaminated sediment assessment considering that PAHs represent the most abundant organic group of compounds in marine environment, opening new perspectives in understanding the molecular pathways activated by crustaceans.

Spatially calibrating polycyclic aromatic hydrocarbons (PAHs) as proxies of area burned by vegetation fires: Insights from comparisons of historical data and sedimentary PAH fluxes

Many regions worldwide have experienced increasing wildfire activity in recent years and climate changes are predicted to result in more frequent and severe fires. Reconstruction of past fire activity offers paleoenvironmental context for modern and future burning. Pyrogenic polycyclic aromatic hydrocarbons (PAHs) have been increasingly used as a molecular biomarker for fire occurrence in the paleorecord and offer opportunity for nuanced reconstructions of fire characteristics. A suite of PAHs is produced during combustion, and the emission amount and assemblage is influenced by many variables including fuel type, fire temperature, and oxygen availability. Despite recent advances in understanding the controls and taphonomy of these biomass burning markers, the spatial scale of this proxy is unknown. In this paper, measurements of PAH fluxes preserved in a lake sediment archive from the Sierra Nevada, California were compared with a historical geographic information system (GIS) dataset of area burned up to 150 km distance from the lake to determine the spatial scales for which these biomarkers are reliable proxies of biomass burning. The PAH fluxes in the Swamp Lake sediments record a change in the relative anthropogenic and pyrogenic sourcing of PAHs. Anthropogenic pollution sources could explain why some PAHs (fluoranthene (Fl), pyrene (Py), benz[a]anthracene (BaA), retene (Ret), benzo[a]pyrene (BaP), dibenzo[a,h]anthracene (DA) and ideno[1,2,3-cd]pyrene (IP)) did not correlate with area burned within 150 km. This indicates that individual PAHs may have different efficacies in recording area burned and be more susceptible to masking of fire signals by pollution sources. Despite these complications, we find that the PAHs naphthalene (Na), acenaphthene (Ace), fluorene (F), and anthracene (An) are reliable local proxies of area burned (within 40 km), whereas the PAHs phenanthrene (Phe), chrysene (Ch), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), and benzo[g,h,i]perylene (Bghi) are both reliable local (within 36 km) as well as more regional (as much as 75 km for phenanthrene (Phe), chrysene (Ch), and benzo[g,h,i]perylene (Bghi) or 150 km for benzo[b]fluoranthene (BbF) and benzo[k]fluoranthene (BkF)) area burned proxies. Comparisons of PAH fluxes with charcoal accumulation rates in the same sediments suggest that pyrogenic particulate transport modulates low to mid-molecular weight PAHs via adsorption. Overall, the results show that PAH records integrate a combination of spatial signals of area burned and measurement of individual PAHs may enable cross-scale paleofire reconstructions.

Influence of Organic Amendments and Moisture Regime on Soil CO2-C Efflux and Polycyclic Aromatic Hydrocarbons (PAHs) Degradation

In this study, a 30-day incubation experiment was performed to investigate the interactive effects of soil moisture content and two types of organic manure (animal manure: M and wheat straw: WS) on organic C mineralization and the degradation of PAH compounds. Specifically, washed sandy soil sample free from PAHs was treated with combined standard solution containing six different PAHs; pyrene (Pyr), fluoranthene (Flt), benzo[a]pyrene (BaP), benzo[g,h,i]perylene (BghiP), benzo[k]fluoranthene (BkF), and indeno[123-cd]pyrene (IP). The soil samples treated with PAHs were amended with M or WS and then, the soil samples were incubated and subjected to two levels of moisture content (50% and 100% field capacity, FC). The results indicate that CO2–C rates were the highest at day 1, but they tended to be decreased sharply when incubation time increased. The results showed that the higher rate of CO2-C efflux rate and cumulative were observed in M and WS treatments at 100% FC. Applying organic amendments at 50% FC increased the total cumulative CO2-C from 21.6 mg kg−1 to 228 mg kg−1 for M and to 216 mg kg−1 for WS. Meanwhile, applying organic amendments at 50% FC increased the total cumulative CO2-C from 30 mg kg−1 to 381 mg kg−1 for M and to 492 mg kg−1 for WS. The highest increases at 100% FC could be explained by the optimum water content at field capacity. PAHs concentrations decreased significantly in the presence of organic amendments in relation to enhance CO2-C efflux (soil respiration) and to decrease soil pH. It could be concluded that applying organic amendments might be a useful technique to remediate soil PAHs through mineralization.

Variations in traffic-related polycyclic aromatic hydrocarbons in PM2.5 in Kanazawa, Japan, after the implementation of a new vehicle emission regulation

A three-year sampling campaign was conducted at a roadside air pollution monitoring station in the urban area of Kanazawa, Japan. Due to a new emission regulation, PAHs levels decreased over the sampling campaign, exhibiting values of 706 ± 413 pg/m3 in 2017, 559 ± 384 pg/m3 in 2018, and 473 ± 234 pg/m3 in 2019. In each year, similar seasonal variations in PAHs levels were observed, with higher levels observed in winter and lower levels in summer. Among the PAHs isomer ratios, we observed that the ratio of benzo[b]fluoranthene (BbF) and benzo[k]fluoranthene (BkF), [BbF]/([BbF] + [BkF]), and the ratio of indeno[1,2,3-cd]pyrene (IDP) and benzo[ghi]perylene (BgPe), [IDP]/([BgPe] + [IDP]), showed stability over the sampling campaign and were less affected by the new emission regulation, seasonal variations, and regional characteristics. When using the combined ratio ranges of 0.66 - 0.80 ([BbF]/([BbF] + [BkF]) and 0.26-0.49 ([IDP]/([BgPe] + [IDP]), traffic emissions were clearly distinguished from other PAHs emission sources. Principal component analysis (PCA) and positive matrix factorization (PMF) were also performed to further analyse the characteristics of traffic-related PAHs. Overall, this study affirmed the effectiveness of the new emission regulation in the reduction of PAHs emissions and provided a combined range for identifying PAHs traffic emission sources.

In vitro profiling of toxic effects of environmental polycyclic aromatic hydrocarbons on nuclear receptor signaling, disruption of endogenous metabolism and induction of cellular stress

Polycyclic aromatic hydrocarbons (PAHs) may interact with multiple intracellular receptors and related signaling pathways. We comprehensively evaluated the toxicity profiles of six environmentally relevant PAHs differing in structure, genotoxicity and their ability to activate the aryl hydrocarbon receptor (AhR). We focused particularly on their impact on intracellular hormone-, xenobiotic- and lipid-sensing receptors, as well as on cellular stress markers, combining a battery of human reporter gene assays and qRT-PCR evaluation of endogenous gene expression in human hepatocyte-like HepaRG cells, with LC/MS-MS analysis of cellular sphingolipids. The effects of PAHs included: activation of estrogen receptor α (in case of fluoranthene (Fla), pyrene (Pyr), benz[a]anthracene (BaA), benzo[a]pyrene (BaP)), suppression of androgen receptor activity (Fla, BaA, BaP and benzo[k]fluoranthene (BkF)), enhancement of dexamethasone-induced glucocorticoid receptor activity (chrysene (Chry), BaA, and BaP), and potentiation of triiodothyronine-induced thyroid receptor α activity (all tested PAHs). PAHs also induced transcription of endogenous gene targets of constitutive androstane receptor (Fla, Pyr), or repression of target genes of pregnane X receptor and peroxisome proliferator-activated receptor α (in case of the AhR-activating PAHs - Chry, BaA, BaP, and BkF) in HepaRG cells. In the same cell model, the AhR agonists reduced the expression of glucose metabolism genes (PCK1, G6PC and PDK4), and they up-regulated levels of glucosylceramides, together with a concomitant induction of expression of UGCG, glucosylceramide synthesis enzyme. Finally, both BaP and BkF were found to induce expression of early stress and genotoxicity markers: ATF3, EGR1, GDF15, CDKN1A/p21, and GADD45A mRNAs, while BaP alone increased levels of IL-6 mRNA. Overall, whereas low-molecular-weight PAHs exerted significant effects on nuclear receptors (with CYP2B6 induction observed already at nanomolar concentrations), the AhR activation by 4-ring and 5-ring PAHs appeared to be a key mechanism underlying their impact on nuclear receptor signaling, endogenous metabolism and induction of early stress and genotoxicity markers.

Polycyclic Aromatic Hydrocarbons in Malt

The kilning of malt occurs at different temperatures, depending on the desired color and aromas. Higher temperatures applied during kilning can be involved in polycyclic aromatic hydrocarbons (PAHs) formation in malt. PAHs are undesirable and designated as health hazards, it is important to quantify and qualify them in different malts. Since the European Food Safety Authority (EFSA) gave strict recommendations about PAHs in different foods, but omitted malt as a potential hazardous raw material that can cause health damage to beer consumers, the aim of this investigation was to assess the presence of 16 PAHs (naphthalene (Nap), acenaphthylene (Anl), acenaphthene (Ane), fluorene (Flu), anthracene (Ant), phenanthrene (Phen), fluoranthene (Flt), benz[a]anthracene (BaA), pyrene (Pyr), chrysene (Chry), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DahA), benzo[ghi]perylene (BghiP), and indeno[1,2,3-cd]pyrene (InP)) in different, commercially available malts (amber, black, pilsner, and cara-120). The results showed that PAHs are present in different malts, with some in high amounts (BaA in black malt was 737 µg/kg). Minimal levels of BaA were detected in the amber malt, 60.53 µg/kg. The PAH4 (BaP, BaA, BbF, and Chry) sums are identical to the BaA concentrations in all malts and greatly exceed the EFSA prescribed levels for PAH4 in processed cereal-based foods (1 µg/kg).

Health risks of PM2.5-bound polycyclic aromatic hydrocarbon (PAH) and heavy metals (PPAH&HM) during the replacement of central heating with urban natural gas in Tianjin, China.

To investigate the health effects of fine particulate matter (≤ 2.5μm in aerodynamic diameter; PM2.5)-bound heavy metals and polycyclic aromatic hydrocarbons (PAHs) before and after the implementation of the Urban Natural Gas Heating Project (UNGHP), the lifetime cancer risks, hazard quotients (HQs) of heavy metals and PAHs were calculated. Seven kinds of heavy metals (Al, As, Cd, Cr, Mn, Ni and Se) and 12 kinds of PAHs including acenaphthylene (ANY), acenaphthene (ANA), fluoranthene (FLT), pyrene (PYR), chrysene (CHR), benz[a]anthracene (BaA), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DBA), benzo[ghi]perylene (BPE) and indeno[1,2,3-cd]pyrene (IPY) were analyzed and used for the health risk assessments. It was found that HQ of Mn fell from 1.09 in the coal-burning period to 0.72 in the gas-burning period in the suburban area. And lifetime cancer risks of PAHs fell from 35.7 × 10-6 in the coal-burning period to 17.22 × 10-6 in the gas-burning period in the urban area. It could be concluded that, during the gas-burning period, downward trends were observed for the lifetime cancer risks and HQs of most kinds of heavy metals and PAHs in all regions of Tianjin compared to those during the coal-burning period. The UNGHP was effective, and we should also take other measures to control the pollution.

The sediment-water diffusion and risk assessment of PAHs in different types of drinking water sources in the Yangtze River Delta, China

PAHs are hazardous and ubiquitous pollutants in the aquatic environment. Understanding their flux, diffusion and environmental risk is very important for the sustainable development of drinking water sources. Thus, PAHs residues were measured with isotope dilution mass spectrometry in sediments, and overlying water of different types of drinking water sources such as rivers, lake, and river networks of Yangtze River Delta. These water bodies are important sources of drinking water, fish, and ecological habitats of various species. The results showed that the ΣPAHs were ranged from 4.25 to 407 ng/L in water, ranked in order as follows: rivers > river networks > lake. ΣPAHs were ranged from 149 to 8023 ng/g dry weight in sediment, ranked in order as follows: river networks > lake > rivers. Low molecular weight PAHs were dominant compounds in water, while high molecular weight PAHs were dominant compounds in sediment. The ffSW values revealed a net resuspension of naphthalene (Nap), acenaphthylene (Dih), fluorine (Flu), phenanthrene (Phe), anthracene (Ant), and benzo[a]pyrene (BaP) from sediment to water in all kind of water sources; indeno[1,2,3-c,d]pyrene (Ind), benzo[b]fluoranthene (BbF), and benzo[k]fluoranthene (BkF) were transferred from water to sediment in Qiantang river but these compounds were at sediment-water equilibrium in Yangtze River, Huangpu River, Jiaxing River Network and Taihu Lake. Acenaphthene (Ace), fluoranthene(Fla), benzo[a]anthracene (BaA), chrysene (Chr), benzo[g,h,i]anthrancene (BPY) were at sediment-water equilibrium at Qiangtang River. PAHs were mainly derived from a mixed source of combustion and petroleum through source resolution. According to quality guidelines, PAHs in sediment posed a potential ecological threat at one site, however, drinking water did not pose any carcinogenic and non-carcinogenic risks.

Sources and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons in the Jiaxing River Network

In order to study the pollution source and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the Jiaxing river network, PAHs were analyzed by GC-MS. The results show that with the influence of rainfall and surface runoff in the wet season, the types and mass concentrations of PAHs in the river network of Jiaxing differ from the dry season. Ten and 16 priority PAHs were detected in the dry season and wet season, respectively. The average mass concentration of PAHs in the dry season was 143.83ng·L-1 and 73.47ng·L-1 in the wet season. The range of mass concentration of PAHs in the dry and wet season was 77.32-283.76ng·L-1 and 13.05-133.02ng·L-1, respectively, and 2-ring and 3-ring PAHs accounted for 79.18% in the dry season and 73.60% in the wet season. PAHs pollution in the river network of Jiaxing was at a low level compared with the domestic and foreign areas. The isomer ratio and principal component analysis found that the PAHs in the Jiaxing river network mainly come from urban non-point source pollution, combustion source, and traffic pollution in the dry season and wet season. The results of the Kalf risk entropy method show that in the dry season, naphthalene(Nap), acenaphthylene(Acy), acenaphthene(Ace), fluorene(Flu), phenanthrene(Phe), anthracene(Ant), fluoranthene(Fla), pyrene(Pyr), and benzo(a)anthracene(BaA) are at moderate ecological risk. In the wet season, Nap, Acy, Flu, Phe, Fla, Pyr, BaA, benzo(b)fluoranthene(BbF), benzo(k)fluoranthene(BkF), benzo(a)pyrene(BaP), indeno(1,2,3-cd)pyrene(InP), and benzo(g,h,i)perylene(BghiP) are at moderate ecological risk. In the dry season, ∑PAHs are at moderate ecological risk, and low in the wet season. On the whole, PAHs pollution in the Jiaxing river network presents moderate ecological risk levels, and measures to reduce the ecological risk of PAHs in the river network should be taken by the Departments concerned.

Microplastic-associated trophic transfer of benzo(k)fluoranthene in a limnic food web: Effects in two freshwater invertebrates (Daphnia magna, Chironomus riparius) and zebrafish (Danio rerio)

The continuously growing plastic production and incomplete recycling processes open manifold entry routes for microplastic particles (MPs) into the environment. Since knowledge on trophic transfer of contaminants sorbed to MPs is still insufficient for freshwater systems, the transfer of the model pollutant benzo(k)fluoranthene (BkF) sorbed to polymethyl methacrylate (PMMA) particles in a limnic food web was investigated: Two freshwater invertebrates (Daphnia magna and Chironomus riparius larvae) were selected and either left untreated, exposed to pristine PMMA, PMMA-associated BkF, or exposed to dissolved BkF (BkFaq). As second-level consumers, zebrafish (Danio rerio) were fed twice daily with pre-treated invertebrates over two days. Induction of hepatic cytochrome P450 by BkF was determined as 7-ethoxy-O-resorufin deethylase (EROD) activity. Both invertebrate species readily ingested PMMA particles, tracked via fluorescence microscopy and accumulated BkFaq, measured via GC–MS. Fluorescence signals in gastrointestinal tracts of zebrafish were quantified with confocal laser scanning microscopy (CLSM). The fluorescence signal in gastrointestinal tracts of zebrafish was not altered, whereas, EROD activity was significantly induced when zebrafish were fed with Chironomus riparius, pre-exposed to BkFaq. Trophic exposure scenarios with BkF sorbed to PMMA did not result in any alterations of investigated endpoints in both invertebrate species and zebrafish compared to controls. Given that BkF amounts were in the low ng-range, as detected by GC–MS, the transport of MP-sorbed BkF to zebrafish was less effective than direct exposure to waterborne BkFaq, and the potential threat of trophic transfer of substances such as BkF in limnic food webs may have been overestimated.

Placental levels of polycyclic aromatic hydrocarbons (PAHs) and their association with birth weight of infants

As an alarming group of pollutants, polycyclic aromatic hydrocarbons (PAHs) gather much public health concern not only because of their carcinogenic or co-carcinogenic risk but also by interfering with hormone systems or by causing oxidative damage, henceforth liable to toxic actions on reproduction. Accordingly, the present study was aimed to explore the association between in-utero exposure to PAHs by evaluating their placental levels and infant birth weight among 110 healthy and nonsmoking pregnant women. Placental tissue samples were collected instantly after delivery and were analyzed for the presence of sixteen Environmental Protection Agency (EPA) listed PAHs with the help of Gas chromatography equipped with flame ionization detector (GC-FID). Chrysene and benzo(k)fluoranthene were the predominant PAHs detected in tissue samples. To assess the source of origin of PAHs in placenta tissue samples, the ratio of low molecular weight PAHs to high molecular weight (∑LMW/∑HMW PAHs) was calculated, showing the predominance of pyrogenic sources of PAHs possibly responsible for the exposure of the studied population. Results of regression analysis demonstrated the inverse although not significant association of naphthalene (Nap), acenaphthylene (Acy), anthracene (Anth), pyrene (Pyr), benzo(b)fluoranthene (BbF), benzo(k)Fluoranthene (BkF), benzo(a)pyrene (BaP), indeno (123 cd pyrene (IcdP), dibenzo(ah)anthracene (DahA) and benzo(ghi)Perylene (BghiP) with birth weight of neonates. Additionally, the regression model lay light upon the significant association of fluoranthene (Fla) (coefficient= −1.41 gram, p < 0.05) to the depletion trend of birth weight after adjusting for potential covariates. These findings suggest the possible role of an environmental contaminants like PAHs on impairment of fetal growth.

Use of eco-friendly magnetic materials for the removal of polycyclic aromatic hydrocarbons and metals from environmental water samples

Abstract Highly toxic pollutants including polycyclic aromatic hydrocarbons (PAHs) and metals such as copper and lead are released into the environment from a variety of sources. One way to remove them from aqueous media is to use magnetic hybrid adsorbents that can be easily separated from the medium after the adsorption process. This work reports the synthesis of a magnetic hybrid matrix consisting of cobalt ferrite as the inorganic phase and natural organic matter (NOM) as the organic phase, where NOM was used instead of the traditional solvents. Tests showed that a hybrid produced using ferric sulfate (FAST) presented higher adsorption efficiency, compared to a hybrid produced using ferric chloride (FACT). PAH adsorption assays were performed using a deionized water solution containing benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP), and dibenzo(a,h)anthracene (DahA), which resulted in removal percentages in the range 83.9–97.6% (q = 41.3–53.7 mg g−1) at equilibrium after 30 min. Tests using real seawater and produced water samples confirmed the efficiency of the hybrid, with removal percentages in the range 86.5–96.3% (q = 43.2–48.1 mg g−1). The highest adsorption of PAHs was achieved using FAST, which was therefore selected for evaluation of metal removal, showing excellent adsorptive capacity, removing 84.5 and 92.0%, respectively, of the copper and lead present in seawater samples. Here, FAST provided efficient removal of both organic and inorganic species, demonstrating its potential for use in technological and environmental applications, including in the manufacturing sector.

Aryl Hydrocarbon Receptor Mediates Larval Zebrafish Fin Duplication Following Exposure to Benzofluoranthenes.

The aryl hydrocarbon receptor (AHR) mediates developmental toxicity of several xenobiotic classes including polycyclic aromatic hydrocarbons. Using embryonic zebrafish, we previously identified 4 polycyclic aromatic hydrocarbons that caused a novel phenotype among AHR ligands-growth of a lateral, duplicate caudal fin fold. The window of sensitivity to the most potent inducer of this phenotype, benzo[k]fluoranthene (BkF), was prior to 36 h postfertilization (hpf), although the phenotype was not manifest until 60 hpf. AHR dependency via Ahr2 was demonstrated using morpholino knockdown. Hepatocyte ablation demonstrated that hepatic metabolism of BkF was not required for the phenotype, nor was it responsible for the window of sensitivity. RNA sequencing performed on caudal trunk tissue from BkF-exposed animals collected at 48, 60, 72, and 96 hpf showed upregulation of genes associated with AHR activation, appendage development, and tissue patterning. Genes encoding fibroblast growth factor and bone morphogenic protein ligands, along with retinaldehyde dehydrogenase, were prominently upregulated. Gene Ontology term analysis revealed that upregulated genes were enriched for mesoderm development and fin regeneration, whereas downregulated genes were enriched for Wnt signaling and neuronal development. MetaCore (Clarivate Analytics) systems analysis of orthologous human genes predicted that R-SMADs, AP-1, and LEF1 regulated the expression of an enriched number of gene targets across all time points. Our results demonstrate a novel aspect of AHR activity with implications for developmental processes conserved across vertebrate species.

Classroom Dust-Bound Polycyclic Aromatic Hydrocarbons in Jeddah Primary Schools, Saudi Arabia: Level, Characteristics and Health Risk Assessment.

Data concerning polycyclic aromatic hydrocarbons (PAHs) in Jeddah’s schools, Saudi Arabia, and their implications for health risks to children, is scarce. Classroom air conditioner filter dusts were collected from primary schools in urban, suburban and residential areas of Jeddah. This study aimed to assess the characteristics of classroom-dust-bound PAHs and the health risks to children of PAH exposure. Average PAH concentrations were higher in urban schools than suburban and residential schools. Benzo (b)fluoranthene (BbF), benzo(ghi)perylene (BGP), chrysene (CRY) and Dibenz[a,h]anthracene (DBA) at urban and suburban schools and BbF, BGP, fluoranthene (FLT) and indeno (1, 2, 3, −cd)pyrene (IND) at residential schools were the dominant compounds in classroom dust. PAHs with five aromatic rings were the most abundant at all schools. The relative contribution of the individual PAH compounds to total PAH concentrations in the classroom dusts of schools indicate that the study areas do share a common source, vehicle emissions. Based on diagnostic ratios of PAHs, they are emitted from local pyrogenic sources, and traffic is the significant PAH source, with more significant contributions from gasoline-fueled than from diesel cars. Based on benzo[a]pyrene equivalent (BaPequi) calculations, total carcinogenic activity (TCA) for total PAHs represent 21.59% (urban schools), 20.99% (suburban schools), and 18.88% (residential schools) of total PAH concentrations. DBA and BaP were the most dominant compounds contributing to the TCA, suggesting the importance of BaP and DBA as surrogate compounds for PAHs in this schools. Based on incremental lifetime cancer risk (ILCingestion, ILCRinhalation, ILCRdermal) and total lifetime cancer risk (TLCR)) calculations, the order of cancer risk was: urban schools > suburban schools > residential schools. Both ingestion and dermal contact are major contributors to cancer risk. Among PAHs, DBA, BaP, BbF, benzo(a)anthracene (BaA), benzo(k)fluoranthene (BkF), and IND have the highest ILCR values at all schools. LCR and TLCR values at all schools were lower than 10−6, indicating virtual safety. DBA, BaP and BbF were the predominant contributors to cancer effects in all schools.

Determination of polycyclic aromatic hydrocarbons (PAHs) in drinking water of Samsun and it's surrounding areas, Turkey.

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. 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. 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 ± 0.24ng/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 ± 3.82ng/L, 3.79 ± 1.27ng/L, 1.08 ± 0.62ng/L, 2.42 ± 1.04ng/L; 1.92 ± 0.35ng/L and 4.07 ± 2.33ng/L respectively. The average (BaP) concentrations for the same named locations were determined as 0.97 ± 0.75ng/L; 0.55 ± 0.29ng/L; 0.11 ± 0.08ng/L; 0.35 ± 0.10ng/L; 0.14 ± 0.04ng/L; 0.39 ± 0.23ng/L, respectively. It is therefore evident that the values ​​of PAH and BaP in drinking water were below the limits of 100 and 10ng/L ​​specified in the Regulation on Water Intended for Human Consumption. These values are below the set limits proposed by Turkish legislation and WHO. 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.

High cancer risk from inhalation exposure to PAHs in Fenhe Plain in winter: A particulate size distribution-based study

Fenhe Plain is a typical region polluted combinedly by coal combustion and coking activities with serious air pollution problem, especially in winter. In order to clarify the size distribution and health risk of polycyclic aromatic hydrocarbons (PAHs) in winter of the Fenhe Plain, the respirable aerosol particles (PM10) were collected by cascade impactor, and 17 PAHs were analyzed. The results showed that the average mass concentration of PM10-bound PAHs was 689.19 ng/m3, which was higher than that in many other domestic and overseas cities. The particulate PAHs mainly distributed in the <0.95 μm size range, accounting for more than 60% of the total. Under the combined influence of local emissions, low temperature, low intensity of solar radiation, dry atmosphere and Kelvin effect, naphthalene (Nap) displayed a bimodal distribution, while the rest of the 17 PAHs all followed a nearly unimodal size distribution. Wind and humidity were important factors which could influence the size distribution of PAHs. Coefficient of divergence (CD) analysis showed that PAHs between all of the sizes had a high spatial heterogeneity in source factor contributions, although diagnostic ratio indicated similar sources among them. Health risk assessment found that the lifetime cancer risk of exposure to particulate PAHs was 1693.76 parts per million people. Ultrafine particles (<0.95 μm) predominated the total carcinogenicity of the particulate PAHs, while benzo(a)pyrene (BaP), dibenzo(a,h)anthracene (DahA), benzo(b)fluoranthene (BbF), benzo(a)anthracene (BaA), benzo(k)fluoranthene (BkF) and indeno(1,2,3-cd)pyrene (IcdP) were the major carcinogenic components. Traffic exhausts contributed most to the carcinogenic PAHs, followed by coal combustion and coking. Our study can provide reference for the pollution control and residential health protection in Fenhe Plain, and bring more reasonable parameterizations to the estimation of PAHs outflow from this key region to other international regions.

Comparison of PAH content, potential risk in vegetation, and bare soil near Daqing oil well and evaluating the effects of soil properties on PAHs.

As the largest oil field in China, Daqing oil field has been developed in the past six decades. The objectives of this study were to measure the levels of polycyclic aromatic hydrocarbons (PAHs) and assess their ecological risk of PAHs in vegetation soil and bare soil near oil well in Daqing and surrounding soil. Ten sites were selected from two types of soil in grassland: vegetation soil (VS, n = 5) and bare soil (BS, n = 5). The mean concentration of 16 PAHs (∑16 PAHs) was 2240.2μg/kg. The mean concentrations of eight carcinogenic PAHs (∑8c PAHs) was 1312.3μg/kg which accounts for 59% of ∑16 PAHs. The sampling sites had higher proportions of high weight molecular ringed PAHs with higher proportions of benzo (a) pyren (BaP) and benzo (k) fluoranthene (BkF). The main source of PAHs was petroleum, coal/biomass combustion, and vehicular emission in these sampling sites. According to Canadian soil quality guidelines, 60% sites had a significant risk to human health. Moreover, 50% sites had high ecological risk and 30% sites were close to this critical value. Notably, PAH levels were significantly higher in VS than BS; moreover, VS had higher organic matter (OM) content, soil dehydrogenase (sDHA) activity, and lower pH and salt content. A structural equation model was established to explore the effects of soil properties on PAH concentration in VS. The result revealed that OM and sDHA were meaningful to enhance the adsorption and biological fixation of PAHs. This study will provide basic information on PAH level and potential application for phytoremediation.

Comamonas sp. 3ah48 is a dibenz[a,h]anthracene-degrading bacterium that is tolerant to heavy metals.

Industrialization often causes polycyclic aromatic hydrocarbon (PAH) and heavy metal contamination of soil and water. In this study, we isolated a bacterium from bottom mud water around a park of Kawasaki Port, Japan, that degrades the 5-ring PAH dibenz[a,h]anthracene (DBA). The strain, Comamonas sp. 3ah48, degraded 29% of DBA (30μg ml-1 ) in 7days, and the degradation level increased drastically, to 59%, by the addition of glutamate to the medium. The strain also degraded 40, 14, 15 and 19% of pyrene (Pyr), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF) and benzo[g,h,i]perylene (BghiP) respectively. Benzo[a]pyrene (BaP) was degraded only when glutamate was added to the medium. Strain 3ah48 retained its degradation levels in the presence of 2mmol l-1 Co2+ , Zn2+ or Cr2+ , at almost the same level as that without metal, and increased the DBA degradation level to 57% in the presence of 2mmol l-1 Cu2+ , suggesting the possibility of the presence of laccase. SIGNIFICANCE AND IMPACT OF THE STUDY: Sixteen polycyclic aromatic hydrocarbons (PAHs) are listed as priority pollutants by the United States Environmental Protection Agency (USEPA). Information about the biodegradation of one of those PAHs, dibenz[a,h]anthracene (DBA), is limited. The present study focuses on DBA degradation by Comamonas sp. 3ah48 strain isolated around Kawasaki Port, Japan. Comamonas sp. 3ah48, cultured with the addition of glutamate to the medium, was found to increase the degradation level of DBA and to degrade DBA even in the presence of high concentrations of heavy metals.

Discrimination of polycyclic aromatic hydrocarbons based on fluorescence spectrometry coupled with CS-SVM

A new approach for discrimination of polycyclic aromatic hydrocarbons (PAHs) in environment was proposed based on fluorescence coupled with CS-SVM. Two groups of experiments were carried out on PAHs with similar spectra. The first one was PAHs any two among benzo[k]fluoranthene (BkF), benzo[b]fluoranthene (BbF) and benzo[a]pyrene (BaP). The second one was naphthalene (NAP) and fluorene (FLU) with similar spectra. The BaP-BkF mixture, BaP-BbF mixture and BbF-BkF mixture with similar fluorescence properties, cuckoo search algorithm (CS) optimizing support vector machine (SVM) was used to discriminate these three mixtures. By comparison with the basic grid search algorithm (GS), genetic algorithm (GA) and particle swarm optimization algorithm (PSO) optimizing SVM, it was found that fitting degree of CS was the best and the convergence speed was also the fastest. The test sample classification accuracy of CS-SVM can reach 100%, which was higher than that of GS-SVM, GA-SVM and PSO-SVM. In order to verify the validity of the proposed approach, all the above methods were applied to discriminate NAP and FLU with extremely similar spectra. The test sample classification accuracy can reach 100%. The satisfying results indicated that the proposed approach had potential to be an alternative approach for discriminating PAHs in environment.

Polycyclic aromatic hydrocarbons in urban road dust, Afghanistan: Implications for human health

Polycyclic aromatic hydrocarbons (PAHs) were analyzed in road and aerial dust to assess their concentration, composition profile, distribution, emission sources, and potential human health risks. Sixteen priority PAHs and Benzo [e]pyrene (BeP) were analyzed in 13 aerial dust samples from Jalalabad, and 78 road dust samples from Kabul and Jalalabad cities, Afghanistan. The mean concentration of ∑17PAHs in road dust from Kabul and Jalalabad were 427 μg kg−1 and 288 μg kg−1, respectively whereas ∑17PAHs in aerial dust from Jalalabad averaged 200 μg kg−1. Fluoranthene (Flu), Chrysene (Chr), Benzo [b]fluoranthene (BbF), Benzo [k]fluoranthene (BkF) and BeP were major individual PAH species. The composition patterns of the PAHs were dominated by 5-6-ring PAHs (51% in road dust from Kabul; 44% in road dust from Jalalabad; and 44% in aerial dust) followed by 4-ring and 2-3-ring PAHs. Source apportionment of the road dust PAHs by the molecular diagnostic ratios (MDR) and principal component analysis (PCA), indicated signatures of PAHs sources (including vehicular exhaust, coal/wood combustion and oil spill). The Benzo [a]pyrene (BaP) toxicity equivalent values (BaPeq17PAHs) for road dust were 75 μg kg−1 (Kabul) and 36 μg kg−1 (Jalalabad); and 35 μg kg−1 for aerial dust (Jalalabad). BaP and Dibenz [a,h]anthracene (DahA) together contributed > 50% of the BaPeq associated cancer risk. All incremental lifetime cancer risk (ILCR) due to human exposure to road and aerial dust PAHs were in the order of 10−7, which is one-fold lower than the threshold (10−6). The noncancerous risk (Hazard Index < 1) on exposure to dust was also negligible for both subpopulations.