Assessment of biological community in riparian zone contaminated by PAHs: Linking source apportionment to biodiversity.

Riparian zone, an important land-water interface, plays an essential role in maintaining the ecological health of rivers, whereas the effects of Polycyclic aromatic hydrocarbons (PAHs) on the health of biological communities in riparian groundwater remain undetermined. To understand the responses of multiple communities to environmental variables, the distribution and ecosystem risk of 16 PAHs have been investigated in the Beiluo River, China. The distribution of multiple communities in riparian groundwater was investigated by environmental DNA metabarcoding, including 16S rRNA, 18S rRNA, and COI gene sequencing for bacteria, microbial eukaryotes (including algae, fungi, and protozoa), and metazoan, respectively, followed by correlation analysis between multiple communities and PAH contamination levels. The concentration of PAHs in the Beiluo River ranged largely from 35.32 to 728.59 ng/L. Here, the Shannon's diversity index of bacteria (Firmicutes) decreased possibly due to the occurrence of Pyrene, which mainly derives from coal and biomass combustion. Furthermore, the reduced richness of fungi (Ascomycota, Basidiomycota) and algae (Chlorophyta, Chrysophyceae) can be attributed to the presence of medium molecular weight (MMW) PAHs (Pyrene, Benz(a)anthracene, Chrysene), and low molecular weight (LMW) PAHs (Naphthalene, Fluorene, Phenanthrene). The richness and Shannon's diversity index of metazoan (Arthropoda) were promoted owing to MMW PAHs (Chrysene, Fluoranthene) generated from coal and biomass combustion and traffic emission. The ecological risk of PAHs in the groundwater environment of the Beiluo River was characterized as low to medium, where LMW and MMW PAHs posed higher risk than the high molecular weight (HMW) compounds. Overall, this study provides insights into the structures of riparian multi-biological communities altered by PAHs.

Occurrence of 3-nitrobenzanthrone and other powerful mutagenic polycyclic aromatic compounds in living organisms: polychaetes.

In this work we report the occurrence of powerful mutagenic 3-nitrobenzanthrone (3-NBA), in addition to 18 polycyclic aromatic hydrocarbons (PAHs), 6 oxygenated PAHs and 27 nitrated PAHs in polychaete worms. Benzanthrone (BA), another important mutagenic polycyclic aromatic compound (PAC) also was detected in the samples. Polychaete annelids have great ecological relevance, being widely distributed in different environmental conditions, from intertidal zones up to seven thousand feet deep areas. They are abundantly found in both contaminated and uncontaminated areas and, therefore, used as indicators of the pollution status of a given area. As we know, so far, most of these PACs has not been previously reported in living organisms before. The 3-NBA concentrations determined in this study were within 0.11-5.18 µg g-1. Other relevant PACs such as PAHs, quinones and nitro-PAHs were found in maximum concentrations at 0.013 µg g-1 (coronene) to 11.1 µg g-1 (benzo[k]fluoranthene), 0.823 µg g-1 (9,10-phenenthrenequinone) to 12.1 µg g-1 (1,4-benzoquinone) and 0.434 (1-nitronaphthalene) µg g-1 to 19.2 µg g-1 (6-nitrobenzo[a]pyrene), respectively. Principal component analysis (PCA), ternary correlations and diagnostic ratios were employed in order to propose probable sources for PACs. Although statistical analysis preliminarily has indicated both pyrogenic and petrogenic contributions, petrogenic sources were predominant reflecting the impacts of petroleum exploration and intensive traffic of boats in the study area.

[Study on occupational exposure characteristics of Polycyclic Aromatic Hydrocarbons in workers of Carbon Enterprises].

Objective: To investigate the characteristics of occupational exposure to polycyclic aromatic hydrocarbons (PAHs) in the workplace and for various types of work in a carbon enterprise based on the measurement data of various components of PAHs in the air from the workplace of the carbon enterprise, and to provide a scientific basis for protection against PAHs in this enterprise. Methods: In July 2017, a carbon enterprise in Shandong Province and its on-duty workers were chosen as subjects. On-site occupational hygiene investigation and high-performance liquid chromatography were used to investigate and determine the presence and concentrations of PAHs in various workshops and various types of work in the enterprise, and toxic equivalent quantity (TEQ) was used to evaluate the carcinogenic level of PAHs. Results: The components of PAHs with relatively high content in the air of the workplace in the carbon enterprise were fluoranthene, pyrene, benzanthracene, X, and benzo[a]pyrene, with mean concentrations of 1 485.66, 864.66, 805.35, 500.08, and 120.88 ng/m(3), respectively. There were significant differences between the three workshops in the concentrations of PAHs components (benzo[a]pyrene, benzanthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, X, fluoranthene, pyrene, fluorene, indenopyrene, and anthracene) and total TEQ (P<0.05) . The total TEQ of PAHs in the molding workshop was significantly higher than that in other workshops (P<0.05) . There were significant differences between different types of work in the exposure to pyrene and fluoranthene and TEQ (P<0.05) . Shaking-table operators, moving-sieve operators, batching operators, fabric workers, and hot-oil stove workers had higher exposure levels of PAHs. The exposure concentrations of benzo[a]pyrene and benzanthracene were highly correlated with total TEQ. Conclusion: The concentration of PAHs in the working environment of the carbon enterprise is generally higher; benzo[a]pyrene and fluoranthene are the PAHs components against which special protective measures need to be taken; molding workshops are the workshops that are most seriously endangered by PAHs; shaking-table operators are the type of workers needing special protection against PAHs. The occupational hazards of PAHs in the carbon industry cannot be ignored, against which corresponding protective measures should be formulated based on their exposure characteristics.

Assessment of concentration of polycyclic aromatic hydrocarbons (PAHs) in vegetables from farms in Accra, Ghana.

Ingestion of leafy vegetables is an important dietary component of most Africans due to its health benefits. High levels of polycyclic aromatic hydrocarbons (PAHs) in the leafy vegetables may pose a significant health hazard to the consumers. Rose/Hibiscus, Chinese cabbage, lettuce, and garden egg leaves from farms along the Nima Creek, Accra, were selected. At each sampling site, the vegetable was uprooted and cut into leaves, stem, and root and analyzed differently. The GC-MS method was employed in the identification and quantification of 16 PAHs in the samples. The analysis was done at CSIR - Water Research Institute Organic Laboratory. The results obtained show concentrations of acenapththylene, acenapthene, benzo[a]anthracene, benzo[b]fluoranthene, and benzo[a]pyrene (except chrysene and pyrene which were found in garden egg leaves and Chinese cabbage respectively), while naphthalene was detected in all the vegetables. The mean concentration of phenanthrene in leaves, stem, and roots of Chinese cabbage vegetable varies according to the following order: roots (0.744 ± 0.16 µg/kg) ≥ leaves (0.598 ± 1.21 µg/kg) ≥ stem (0.327 ± 1.01 µg/kg). From the results of the isomeric ratios, the source of the PAHs in the leafy vegetables are from mixed sources, i.e., either pyrogenic and petrogenic origins. This calls for the formulation of stringent policies on the importation of over-age vehicles into the countries as well as on the indiscriminate burning of materials containing PAHs.

Role of Human Aldo-Keto Reductases in the Metabolic Activation of the Carcinogenic Air Pollutant 3-Nitrobenzanthrone.

3-Nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen detected in diesel exhaust particulate and ambient air pollution. It requires metabolic activation via nitroreduction to promote DNA adduct formation and tumorigenesis. NAD(P)H:quinone oxidoreductase 1 (NQO1) has been previously implicated as the major nitroreductase responsible for 3-NBA activation, but it has recently been reported that human aldo-keto reductase 1C3 (AKR1C3) displays nitroreductase activity toward the chemotherapeutic agent PR-104A. We sought to determine whether AKR1C isoforms could display nitroreductase activity toward other nitrated compounds and bioactivate 3-NBA. Using discontinuous enzymatic assays monitored by UV-HPLC, we determined that AKR1C1-1C3 catalyze three successive two-electron nitroreductions toward 3-NBA to form the reduced product 3-aminobenzanthrone (3-ABA). Evidence of the nitroso- and hydroxylamino- intermediates were obtained by UPLC-HRMS. Km, kcat, and kcat/ Km values were determined for recombinant AKR1C and NQO1 and compared. We found that AKR1C1, AKR1C3, and NQO1 have very similar apparent catalytic efficiencies (8 vs 7 min-1 mM-1) despite the higher kcat of NQO1 (0.058 vs 0.012 min-1). AKR1C1-1C3 possess a Km much lower than that of NQO1, which suggests that they may be more important than NQO1 at the low concentrations of 3-NBA to which humans are exposed. Given that inhalation represents the primary source of 3-NBA exposure, we chose to evaluate the relative importance of AKR1C1-1C3 and NQO1 in human lung epithelial cell lines. Our data suggest that the combined activities of AKR1C1-1C3 and NQO1 contribute equally to the reduction of 3-NBA in A549 and HBEC3-KT cell lines and together represent approximately 50% of the intracellular nitroreductase activity toward 3-NBA. These findings have significant implications for the metabolism of nitrated polycyclic aromatic hydrocarbons and suggest that the hitherto unrecognized nitroreductase activity of AKR1C enzymes should be further investigated.

PAHs contamination in edible gastropods from north Patagonian harbor areas.

PAHs are persistent pollutants released into the environment by fossil fuels burning and leak during petroleum operations. Associated with suspended particles upon entering marine ecosystem are accumulated by benthic fauna. Human exposure occurs mainly from ingestion such as gastropods consumption. The objective was to determine PAHs in sediments and in the marine gastropod Buccinanops globulosus in sites with different maritime and urban influences. In sampling sites located 20 km from the harbor, PAHs were non-detected; while in harbor gastropods, the level of PAH4 was exceeded according to international normative. Level of dibenzo[a,h]anthracene in sediments was between the ISQG and PEL. Since these are the first results of PAHs in edible gastropods in South America, we concluded that PAHs can be dangerous for consumers according to ingestion frequency. Integrative studies are necessary to evaluate the interaction among pollutants in maritime areas and the incidence in human health due to shellfish consumption.

High-resolution turbulent flow chromatography.

The resolution power of turbulent flow chromatography using carbon dioxide as the mobile phase and coated (crosslinked methyl phenyl polysiloxane) open tube columns (OTCs) as the stationary phase was investigated under retentive conditions (0

Polycyclic aromatic hydrocarbons in teas using QuEChERS and HPLC-FLD.

Polycyclic aromatic hydrocarbons (PAHs) are food-processing contaminants considered to be carcinogenic and genotoxic. Due to its drying process stage, teas may be contaminated with PAHs. The aim of the study was to validate an analytical method involving QuEChERS and HPLC-FLD for the determination of PAH4 in teas and evaluate the contamination levels in 10 different types of teas from Brazil. Recoveries varied from 54% to 99% and relative standard deviations from 1% to 21%. Limits of detection and quantification were from 0.03 to 0.3 µg/kg and 0.1 to 0.5 µg/kg, respectively. Mate tea presented the highest PAH levels, with PAH4 varying from 194 to 1795 µg/kg; followed by black (1.8-186 µg/kg), white (24-119 µg/kg), and green teas (3.1-92 µg/kg). Teas with lowest PAH4 were strawberry, lemongrass, peppermint, and boldo. Only trace levels of PAHs were detected in tea infusions, so apparently it would not affect PAH intake by Brazilian population.

Spatial variation of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from rivers in hilly regions of Southern China in the wet and dry seasons.

Seasonal variations of polycyclic aromatic hydrocarbons (PAHs) in the surface sediments from 13 rivers in hilly regions of southern China were studied. Concentrations of PAHs analyzed in the wet season were higher than those analyzed in the dry season, with residues ranging from 74.3 to 1930.9 ng g-1 dw in the wet season and from 96.9 to 1388.9 ng g-1 dw in the dry season. The primary contributors were 3- and 4-ringed congeners accounting for 59.8% ±â€¯10.1% and 58.3% ±â€¯9.3% of the identified PAHs in the wet and the dry seasons, respectively. Proximity to sources and locations susceptible to high atmospheric depositional inputs results in high concentrations of PAH. Diagnostic ratios have indicated that the sources of PAHs in different seasons make no apparent difference. Furthermore, a principal component analysis and multiple linear regression (PCA-MLR) studies indicate that combustion sources such as vehicle emissions and coal combustion are the primary sources of PAHs. Toxicological risk assessments based on TEQcare suggested that Benzo[a]pyrene, benz[a]anthracene, dibenz[a,h]anthracene could pose high ecological risks in this area.

Optimisation of extraction methods and quantification of benzo[a]pyrene and benz[a]anthracene in yerba maté tea by isotope dilution mass spectrometry.

A gas chromatography-isotope dilution mass spectrometry (GC-IDMS) technique was developed for the quantification of two heavy polyaromatic hydrocarbons (PAHs), benz[a]anthracene and benzo[a]pyrene, in yerba maté tea (maté). The optimisation of two extraction methods, namely liquid-liquid extraction and accelerated solvent extraction, was carried out. Both optimised methods were validated using a certified reference material of fine dust and the results were within the expanded uncertainties at 95% confidence level. Recoveries of 99.2-106.7% with RSD of measurements of 1.1-2.3% were achieved for benz[a]anthracene. Recoveries of 95.7-101.9% with RSD of measurements of 0.4-1.4% were achieved for benzo[a]pyrene. The validated methods were applied for the extraction of benz[a]anthracene and benzo[a]pyrene in maté powder from NIST. A metrological approach was undertaken to ensure the traceability of measurement results. The uncertainties associated with the results were rigorously evaluated and also reported herein. Graphical abstract Quantification of benz[a]anthracene and benzo[a]pyrene using IDMS.

Appraisement, source apportionment and health risk of polycyclic aromatic hydrocarbons (PAHs) in vehicle-wash wastewater, Pakistan.

Vehicle-wash wastewater (VWW) contains elevated concentrations of different petrochemicals including polycyclic aromatic hydrocarbons (PAHs), a carcinogenic group of organic compounds. This study investigates the discharge of PAHs present in the untreated wastewater of vehicle-wash stations (VWS) located in district Peshawar, Pakistan. The data obtained was being novel with the detection of 16 USEPA PAHs (both individuals and total) and compared with earlier studies and international standards. The ∑16PAHs in wastewater from light vehicle-wash stations (LVWS) and heavy vehicle-wash stations (HVWS) ranged from 245-429µg/l and 957-1582µg/l, respectively. A significant difference (p<0.01) was observed in PAHs discharged from LVWS and HVWS. The projected ∑16PAHs discharge from both HVWS (92% of total generated PAHs) and LVWS (8%) was about 5109.9 g per annum. According to PAH diagnostic ratios, PAHs were both petrogenic (chrysene/benz(a)anthracene, low molecular weight/high molecular weight) and pyrogenic (phenanthrene/anthracene, fluoranthene/pyrene, fluoranthene/fluoranthene+pyrene) in origin. The highest toxic equivalent quotient (TEQ) value was shown by benzo(a)pyrene (21.6µg/l) followed by dibenz(ah)anthracene (9.81µg/l) in wastewater from HVWS. However, in LVWS the case was reversed with highest value (7.54µg/l) for dibenz(ah)anthracene followed by benzo(a)pyrene (3.54µg/l). The lowest TEQ value was indicated for phenanthrene (0.007µg/l) in wastewater of LVWS, while pyrene showed the lowest value (0.007µg/l) in wastewater of HVWS. The results indicated that VWS contribute significant amount of PAHs each year, which is of great concern regarding water quality, ecological and human health risk. This is the first systematic and comprehensive research related with generation of PAHs load per day, week, month and annum from VWS, their source apportionment and health effects in Pakistan.

Study of persistent toxic pollutants in a river basin-ecotoxicological risk assessment.

This study presents a complementary approach for the evaluation of water quality in a river basin by employing active and passive sampling. Persistent toxic pollutants representing three classes: organochlorinated pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), were studied in grab water samples, in passive samplers/SemiPermeable Membrane Devices (SPMDs) and in fish tissues collected along the Strymonas River, northern Greece at three sampling campaigns during the year 2013. Almost all the target compounds were detected in the study river of Strymonas, northern Greece at the periods of high rainfall intensity and/or low flow-rate. The most frequently detected compounds were 1,2-benzanthracene, benzo(a)pyrene, benzo(b)fluoranthene, endosulfan I, endosulfan II, endosulfan sulfate, endrin aldehyde, fluorene, methoxychlor, polychlorinated biphenyl PCB 28, PCB 180 and pyrene. The family of DDT compounds and aldrin were also occasionally detected. Agricultural run-off and waste effluents are the main sources of hydrophobic organic compounds in the river basin. The use of SPMDs allowed the detection of more micropollutants than active sampling (31 vs. 16, respectively). Results showed relatively low risk however the potential risk associated with micropollutants such as 1,2-benzanthracene, benzo(b)fluoranthene, p,p-dichlorodiphenyldichloroethane (DDD), endosulfan II, methoxychlor, PCB 180 and pyrene should not be neglected. Performing risk assessment based on passive sampling, more information was obtained about temporal and spatial variation. SPMDs could be applied as a pre-evaluation before chemical monitoring in biota.

On-line SPE chromatography with spectrophotometric diode array detection as a simple and advantageous choice for the selective trace analysis of benzo(a)anthracene degradation products from microalgae.

In this work, a methodology based on on-line solid phase extraction (SPE) chromatography with spectrophotometric diode array detection was optimized and validated for the trace analysis of benzo(a)anthracene dihydrodiol degradation products from microalgae cultures 5,6-dihydrodiol, 8,9-dihydrodiol and 10,11-dihydrodiol. The two on-line methods for the constituents of the culture, an SPE/on-line SPE chromatographic method for liquid medium and a matrix solid phase dispersion (MSPD)/on-line SPE chromatographic method for biomass presented good linearity in the ranges of 0.5-47ngmL-1 and 2-80ngmg-1 of samples, respectively, with correlation coefficients r>0.99. The percent relative standard deviation (RSD%) values were ≤4.9%. For the liquid medium and biomass methods, the global recoveries were between 84% and 90% and between 67% and 78%, and the limit of detection LODs were ≤0.3ngmL-1 and ≤0.8ngmg-1 respectively. The methodology was applied to exposure bioassays, and for the first time the three metabolites were detected and quantified individually by their appearance in the biomass and when they were excreted into the liquid medium. The metabolite formed in the greatest amount was 10,11-dihydrodiol, and the maximum production of all metabolites was at 6h of exposure. This work contributes to the study of the degradation route of BaA, which has not been elucidated for microalgae until now.

Polycyclic aromatic hydrocarbons in commercial brands of dry whole soybeans for direct human consumption.

A total of 13 polycyclic aromatic hydrocarbons (PAHs) were surveyed in dry whole soybeans (Glycine max L.) sold for human consumption. The analysed samples were commercialised in vegetarian shops and food stores in Southern Brazil regions. The determination of PAHs levels was carried out by high performance liquid chromatography (HPLC)with fluorescence detection. PAHs were present in 89.7% of the samples. Chrysene (Chy) and 5 methyl chrysene (5MeChy) were the main PAHs detected (76.9% and 71.8%, respectively) followed by dibenzo(ai)pyrene (DaiP), however in a much less percentage of samples (23.1%). Apart from those PAHs, also benzo(a)antracene (BaA), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF) and benzo(a)pyrene(BaP) were found. The ΣPAH levels in the positive samples ranged from 0.80 to 38.78 µg kg-1, with exception of one sample that reached 204.46 µg kg-1 (ΣPAHs of six compounds). Despite the present contamination there are no maximum limits set for PAHs in soybeans.

Bioaccessibility of nitro- and oxy-PAHs in fuel soot assessed by an in vitro digestive model with absorptive sink.

Ingestion of soot present in soil or other environmental particles is expected to be an important route of exposure to nitro and oxygenated derivatives of polycyclic aromatic hydrocarbons (PAHs). We measured the apparent bioaccessibility (Bapp) of native concentrations of 1-nitropyrene (1N-PYR), 9-fluorenone (9FLO), anthracene-9,10-dione (ATQ), benzo[a]anthracene-7,12-dione (BaAQ), and benzanthrone (BZO) in a composite fuel soot sample using a previously-developed in vitro human gastrointestinal model that includes silicone sheet as a third-phase absorptive sink. Along with Bapp, we determined the 24-h sheet-digestive fluid partition coefficient (Ks,24h), the soot residue-fluid distribution ratio of the labile sorbed fraction after digestion (Kr,lab), and the maximum possible (limiting) bioaccessibility, Blim. The Bapp of PAH derivatives was positively affected by the presence of the sheet due to mass-action removal of the sorbed compounds. In all cases Bapp increased with imposition of fed conditions. The enhancement of Bapp under fed conditions is due to increasingly favorable mass transfer of target compounds from soot to fluid (increasing bile acid concentration, or adding food lipids) or transfer from fluid to sheet (by raising small intestinal pH). Food lipids may also enhance Bapp by mobilizing contaminants from nonlabile to labile states of the soot. Compared to the parent PAH, the derivatives had larger Kr,lab, despite having lower partition coefficients to various hydrophobic reference phases including silicone sheet. The Blim of the derivatives under the default conditions of the model ranged from 65.5% to 34.4%, in the order, 1N-PYR > ATQ > 9FLO > BZO > BaAQ, with no significant correlation with hydrophobic parameters, nor consistent relationship with Blim of the parent PAH. Consistent with earlier experiments on a wider range of PAHs, the results suggest that a major determinant of bioaccessibility is the distribution of chemical between nonlabile and labile states in the original solid.

Evaluation of genetic toxicity caused by acid mine drainage of coal mines on fish fauna of Simsang River, Garohills, Meghalaya, India.

Fishery ecology of the Simsang River, Meghalaya is being threatened by large scale environmental degradation due to acid mine drainage (AMD) of coal mines. In the present paper, effort has been made to evaluate the genotoxicity caused due to AMD of coal mines on Channa punctata under laboratory condition through comet assay, micronucleus and chromosome aberration tests. Water samples were collected seasonally from affected and unaffected sites of the River and physico-chemical quality of water indicated low pH (4.6), high concentration of sulphates (270mgL(-1)) and iron (7.2mgL(-1)) beyond permissible limits. Polycyclic aromatic hydrocarbon (PAH) showed highest concentration of 4-ring PAH and Benzo[a]anthracene was the most important pollutant in the water collected from affected sites. The highest and the lowest mean concentrations of PAHs were estimated in monsoon and winter season, respectively. The index of DNA damage assessed by comet assay, micronucleus and chromosome aberration tests demonstrated significant differences season wise in different sampling sites. Frequency of DNA-damaged cells was found highest in the water samples collected from affected site in monsoon season.

Polycyclic aromatic hydrocarbons in cereal products on the Turkish market.

The contamination level of four EU marker polycyclic aromatic hydrocarbons (PAHs) in some cereal-derived products was surveyed in this study. Thirty-eight samples, 20 bread and 18 breakfast cereals, were purchased from retail shops and local markets of East Black sea region in Turkey. The samples were analysed for four EU marker PAHs, using ultrasonic extraction, solid-phase extraction (SPE) clean up and stable-isotope dilution gas chromatography with mass-spectrometric (GC/MS) detection. The method was validated with the parameters linearity, accuracy, precision, limit of detection (LOD), limit of quantitation (LOQ) and uncertainty. Total content of the four PAHs in bread varied from 0.19 to 0.46 µg kg(-1) and in breakfast cereals from 0.10 to 0.87 µg kg(-1).

Use of the Integrated Biomarker Response to Measure the Effect of Short-term Exposure to Dibenz[a,h]anthracene in Common carp (Cyprinus carpio).

Dibenz[a,h]anthracene (DbA) is a polycyclic aromatic hydrocarbon that is released into the environment through incomplete combustion of gasoline, cigarettes, and coal tar. The effects of short-term (10 days) exposure of common carp (Cyprinus carpio) to DbA (0-50 µg L(-1)) were evaluated using the following four biomarkers: DNA damage, 7-ethoxyresorufin-O-deethylase (EROD) activity, acetylcholinesterase (AChE) activity, and vitellogenin (VTG) levels. An integrated biomarker response (IBR) was calculated for exposure to DbA, and the results were compared with those in our previous study of two other PAHs, benzo[k]fluoranthene (BkF) and benzo[a]pyrene (BaP). DbA exposure resulted in a significant (p < 0.05) increase in DNA damage, EROD activity, and VTG levels relative to the control. By contrast, DbA did not affect AChE activity. The IBR increased as the concentration of DbA increased. Based on the IBR values, the order of toxicity for the PAHs was BkF > BaP > DbA. Our results suggest that the IBR can be used as a quantitative tool for evaluating the responses of multiple biomarkers to PAH exposure.

Detection of benz[j]aceanthrylene in urban air and evaluation of its genotoxic potential.

Benz[j]aceanthrylene (B[j]A) is a cyclopenta-fused polycyclic aromatic hydrocarbon with strong mutagenic and carcinogenic effects. We have identified B[j]A in air particulate matter (PM) in samples collected in Stockholm, Sweden and in Limeira, Brazil using LC-GC/MS analysis. Determined concentrations ranged between 1.57 and 12.7 and 19.6-30.2 pg/m(3) in Stockholm and Limeira, respectively, which was 11-30 times less than benzo[a]pyrene (B[a]P) concentrations. Activation of the DNA damage response was evaluated after exposure to B[j]A in HepG2 cells in comparison to B[a]P. We found that significantly lower concentrations of B[j]A were needed for an effect on cell viability compared to B[a]P, and equimolar exposure resulted in significant more DNA damage with B[j]A. Additionally, levels of γH2AX, pChk1, p53, pp53, and p21 proteins were higher in response to B[j]A than B[a]P. On the basis of dose response induction of pChk1 and γH2AX, B[j]A potency was 12.5- and 33.3-fold higher than B[a]P, respectively. Although B[j]A levels in air were low, including B[j]A in the estimation of excess lifetime cancer risk increased the risk up to 2-fold depending on which potency factor for B[j]A was applied. Together, our results show that B[j]A could be an important contributor to the cancer risk of air PM.

Superoxide mediated photomodification and DNA damage induced apoptosis by Benz(a)anthracene via mitochondrial mediated pathway.

Benz(a)anthracene (BA) is an ubiquitous environmental pollutant of polycyclic aromatic hydrocarbon's (PAHs) family. We showed superoxide (O2(-)) catalyzed BA photo modification and apoptosis in HaCaT keratinocytes under sunlight exposure. O2(-) generation was confirmed by quenching through superoxide dismutase (SOD). BA induced photocytotoxicity were investigated through MTT and NRU assay. We proposed DNA insults such as single and double strand breakage and CPDs formation which results in cell cycle arrest and apoptosis by photosensitized BA. BA induced apoptosis was caspase dependent and occurred through a mitochondrial pathway. Reduction of mitochondrial membrane potential, translocation of Bax to mitochondria and cytochrome c release favors involvement of mitochondria in BA phototoxicity. AO/EB double staining and TEM analysis also support apoptotic cell death. We propose a p21 regulated apoptosis via expression of Bax, and cleaved PARP under sunlight exposure. Thus, we conclude that it is imperative to avoid solar radiation during peak hr (between 11A.M. and 3P.M.) when the amount of solar radiation is high, in the light of DNA damage which may lead to mutation or skin cancer through photosensitized BA under sunlight exposure. Concomitantly, investigation is urgently required for the photosafety of BA photoproducts reaching in the environment through photomodification.