Exposure to Benzo[a]pyrene and 1-Nitropyrene in Particulate Matter Increases Oxidative Stress in the Human Body

Polycyclic aromatic hydrocarbons (PAHs) have been reported to cause oxidative stress in metabolic processes. This study aimed to evaluate the relationship between exposure to PAHs, including benzo[a]pyrene (BaP) and 1-nitropyrene (1-NP), in the atmosphere and oxidative stress levels in the human body. This study included 44 Korean adults who lived in Cheongju, Republic of Korea. Atmospheric BaP and 1-NP concentrations and urinary 6-hydroxy-1-nitropyrene (6-OHNP), N-acetyl-1-aminopyrene (1-NAAP), and 1-hydroxypyrene (1-OHP) concentrations were measured. The oxidative stress level was assessed by measuring urinary thiobarbituric acid-reactive substances (TBARS) and 8-hydroxydeoxyguanosine (8-OHdG) concentrations. Urinary TBARS and 6-OHNP concentrations significantly differed between winter and summer. BaP exposure was significantly associated with urinary 8-OHdG concentrations in summer. However, atmospheric 1-NP did not show a significant correlation with oxidative stress marker concentrations. Urinary 1-NAAP concentration was a significant determinant for urinary 8-OHdG concentration in summer. Oxidative stress in the body increases in proportion to inhalation exposure to BaP, and more 8-OHdG is produced in the body as the amount of 1-NP, which is metabolized to 1-AP or 1-NAAP, increases.

Activation of the Keap1/Nrf2 Pathway as an Adaptive Response to an Electrophilic Metabolite of Morphine

Morphinone (MO) is an electrophilic metabolite of morphine that covalently binds to protein thiols via its α,β-unsaturated carbonyl group, resulting in toxicity in vitro and in vivo. Our previous studies identified a variety of redox signaling pathways that are activated during electrophilic stress. Here, we examined in vitro activation of a signaling pathway involving Kelch-like ECH-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor 2 (Nrf2) in response to MO. Exposure of HepG2 cells to MO caused covalent modification of Keap1 thiols (evaluated using biotin-PEAC₅-maleimide labeling) and nuclear translocation of Nrf2, thereby up-regulating downstream genes encoding ATP binding cassette subfamily C member 2, solute carrier family 7 member 11, glutamate-cysteine ligase catalytic subunit, glutamate-cysteine ligase modifier subunit, glutathione S-transferase alpha 1, and heme oxygenase 1. However, dihydromorphinone, a metabolite of morphine lacking the reactive C7-C8 double bond, had little effect on Nrf2 activation. These results suggest that covalent modification is crucial in the Keap1/Nrf2 pathway activation and that this pathway is a redox signaling-associated adaptive response to MO metabolism.

Effects of polycyclic aromatic hydrocarbon exposure on mitochondrial DNA copy number

Airborne polycyclic aromatic hydrocarbon (PAH) exposure can adversely affect human health by generating reactive oxygen species (ROS) and increasing oxidative stress, which causes changes in mitochondrial DNA copy number (mtDNAcn), a key indicator of mitochondrial damage and dysfunction. This study aimed to determine the effects of atmospheric benzo[a]pyrene (BaP) and 1-nitropyrene (1-NP) exposure on mtDNAcn in humans. One hundred and eight adults living in Cheongju, South Korea, were included in this study. Atmospheric BaP and 1-NP concentrations and urinary 6-hydroxy-1-nitropyrene (6-OHNP), N-acetyl-1-aminopyrene (1-NAAP), and 1-hydroxypyrene concentrations were measured. Blood samples were also collected to assess mtDNAcn. The mean mtDNAcn was 9.74 (SD 4.46). mtDNAcn decreased significantly with age but was not significantly associated with sex, sampling season, or smoking habit. While there was a borderline significant increase in mtDNAcn with increasing ambient total PAH levels, ambient PAH or urinary 1-hydroxypyrene concentrations showed no significant association with mtDNAcn. However, urinary 6-OHNP or 1-NAAP concentrations, 1-NP metabolites, were significantly associated with mtDNAcn. These results suggest that the metabolism of absorbed NPs generates excess ROS, which damages mitochondrial DNA, resulting in increased mtDNAcn.

Synthesis and Biological Evaluation of Novel 2-(Benzofuran-2-yl)-chromone Derivatives for In Vivo Imaging of Prion Deposits in the Brain

Prion diseases are fatal neurodegenerative disorders caused by the deposition of scrapie prion protein aggregates (PrP^Sc) in the brain. We previously reported that styrylchromone (SC) and benzofuran (BF) derivatives have potential as imaging probes for PrP^Sc. To further improve their properties, we designed and synthesized 2-(benzofuran-2-yl)-chromone (BFC) derivatives hybridized with SC and BF backbones as novel single-photon emission computed tomography probes for the detection of cerebral PrP^Sc deposits. Recombinant mouse prion protein (rMoPrP) aggregates and mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice were used to evaluate the binding properties of BFC derivatives to PrP^Sc. The BFC derivatives exhibited high binding affinities (equilibrium dissociation constant [K_d] = 22.6-47.7 nM) for rMoPrP aggregates. All BFC derivatives showed remarkable selectivity against amyloid beta aggregates. Fluorescence microscopy confirmed that the fluorescence signals of the BFC derivatives corresponded to the antibody-positive deposits of PrP^Sc in mBSE-infected mouse brains. Among the BFC derivatives, [¹²⁵I]BFC-OMe and [¹²⁵I]BFC-NH₂ exhibited high brain uptake and favorable washout from the mouse brain. In vitro autoradiography demonstrated that the distribution of [¹²⁵I]BFC-OMe in the brain tissues of mBSE-infected mice was colocalized with PrP^Sc deposits. Taken together, BFC derivatives appear to be promising prion imaging probes.

Effects of gene polymorphisms of CYP1A1, CYP1B1, EPHX1, NQO1, and NAT2 on urinary 1-nitropyrene metabolite concentrations

Nitropyrene (1-NP) is a specific indicator of exposure to diesel exhaust and is partly metabolized to 1-aminopyrene (1-AP) and N-acetyl-1-aminopyrene (1-NAAP), which are excreted in urine. This study was conducted to evaluate the effects of gene polymorphisms of metabolic enzymes for 1-NP on the urinary concentrations of 1-AP and 1-NAAP. The study participants were 70 South Koreans who were occupationally or environmentally exposed to diesel exhaust. To evaluate 1-NP exposure levels, we sampled airborne particulate matters with a personal air sampler and measured urinary 1-AP and 1-NAAP concentrations. The genetic polymorphisms of the 1-NP metabolic enzymes (CYP1A1, CYP1B1, EPHX1, NQO1, and NAT2) were determined by direct sequencing. The mean 1-NP exposure level was 20.40 pg/m³, and the mean urinary concentrations of 1-AP and 1-NAAP were 0.074 nM and 0.213 nM, respectively. The correlation coefficient between the 1-NP exposure level and urinary 1-AP concentrations was 0.0138 and that between the 1-NP exposure level and urinary 1-NAAP concentrations was 0.1493, and neither correlation coefficient was statistically significant. The correlation coefficient between the 1-NP exposure level and urinary 1-AP concentrations showed statistically significant differences according to the CYP1A1 and CYP1B1 genotypes, and that between the 1-NP exposure level and urinary 1-NAAP concentrations was significantly different according to the CYP1A1, CYP1B1, and NAT2 genotypes. The urinary concentration of 1-NAAP is a better biomarker for exposure to 1-NP or DEPs because the former is higher, easier to measure, and more strongly correlated with 1-NP exposure levels than that of 1-AP. The relationship between 1-NP exposure and urinary 1-AP or 1-NAAP concentration depends on the single nucleotide polymorphism types of CYP1A1, CYP1B1, NQO1, and NAT2.

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Compared with 1-AP, the urinary excretion of 1-NAAP is nearly three-fold greater.

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1-NAAP showed a stronger correlation with 1-NP exposure than 1-AP and would be a better exposure biomarker.

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The relationship between 1-NP exposure and urinary 1-NAAP concentration depends on the SNP type of the metabolic enzymes.

Redox Homeostasis is Disturbed by Redox Cycling between Reactive Cysteines of Thioredoxin 1 and 9,10-Phenanthrenequinone, an Atmospheric Electron Acceptor

9,10-Phenanthrenequinone (9,10-PQ) is a toxicant in diesel exhaust particles and airborne particulate matter ≤2.5 μm in diameter. It is an efficient electron acceptor that readily reacts with dithiol compounds in vitro, resulting in the oxidation of thiol groups and concomitant generation of reactive oxygen species (ROS). However, it remains to be elucidated whether 9,10-PQ interacts with proximal protein dithiols. In the present study, we used thioredoxin 1 (Trx1) as a model of proteins with reactive proximal cysteines and examined whether it reacts with 9,10-PQ in cells and tissues, thereby affecting its catalytic activity and thiol status. Intratracheal injection of 9,10-PQ into mice resulted in protein oxidation and diminished Trx activity in the lungs. Using recombinant wild-type and C32S/C35S Trx1, we found that Cys32 and Cys35 selectively serve as electron donor sites for redox reactions with 9,10-PQ that lead to substantial inhibition of Trx activity. Addition of dithiothreitol restored the Trx activity inhibited by 9,10-PQ. Exposure of cultured cells to 9,10-PQ caused intracellular reactive oxygen species generation that led to protein oxidation, Trx1 dimerization, p38 phosphorylation, and apoptotic cell death. Overexpression of Trx1 blocked these 9,10-PQ-mediated events. These results suggest that the interaction of the reactive cysteines of Trx1 with 9,10-PQ causes oxidative stress, leading to disruption of redox homeostasis.

Hydroxylated benzo[c]phenanthrene metabolites cause osteoblast apoptosis and skeletal abnormalities in fish

To study the toxicity of 3-hydroxybenzo[c]phenanthrene (3-OHBcP), a metabolite of benzo[c]phenanthrene (BcP), first we compared it with its parent compound, BcP, using an in ovo-nanoinjection method in Japanese medaka. Second, we examined the influence of 3-OHBcP on bone metabolism using goldfish. Third, the detailed mechanism of 3-OHBcP on bone metabolism was investigated using zebrafish and goldfish. The LC50s of BcP and 3-OHBcP in Japanese medaka were 5.7 nM and 0.003 nM, respectively, indicating that the metabolite was more than 1900 times as toxic as the parent compound. In addition, nanoinjected 3-OHBcP (0.001 nM) induced skeletal abnormalities. Therefore, fish scales with both osteoblasts and osteoclasts on the calcified bone matrix were examined to investigate the mechanisms of 3-OHBcP toxicity on bone metabolism. We found that scale regeneration in the BcP-injected goldfish was significantly inhibited as compared with that in control goldfish. Furthermore, 3-OHBcP was detected in the bile of BcP-injected goldfish, indicating that 3-OHBcP metabolized from BcP inhibited scale regeneration. Subsequently, the toxicity of BcP and 3-OHBcP to osteoblasts was examined using an in vitro assay with regenerating scales. The osteoblastic activity in the 3-OHBcP (10-10 to 10-7 M)-treated scales was significantly suppressed, while BcP (10-11 to 10-7 M)-treated scales did not affect osteoblastic activity. Osteoclastic activity was unchanged by either BcP or 3-OHBcP treatment at each concentration (10-11 to 10-7 M). The detailed toxicity of 3-OHBcP (10-9 M) in osteoblasts was then examined using gene expression analysis on a global scale with fish scales. Eight genes, including APAF1, CHEK2, and FOS, which are associated with apoptosis, were identified from the upregulated genes. This indicated that 3-OHBcP treatment induced apoptosis in fish scales. In situ detection of cell death by TUNEL methods was supported by gene expression analysis. This study is the first to demonstrate that 3-OHBcP, a metabolite of BcP, has greater toxicity than the parent compound, BcP.

Synthesis and Characterization of Hydroxyethylamino- and Pyridyl-Substituted 2-Vinyl Chromone Derivatives for Detection of Cerebral Abnormal Prion Protein Deposits

Prion diseases are fatal neurodegenerative diseases characterized by the deposition of abnormal prion protein aggregates (PrP^Sc) in the brain. In this study, we developed hydroxyethylamino-substituted styrylchromone (SC) and 2-(2-(pyridin-3-yl)vinyl)-4H-chromen-4-one (VPC) derivatives for single-photon emission computed tomography (SPECT) imaging of PrP^Sc deposits in the brain. The binding affinity of these compounds was evaluated using recombinant mouse prion protein (rMoPrP) aggregates, which resulted in the inhibition constant (K_i) value of 61.5 and 88.0 nM for hydroxyethyl derivative, (E)-2-(4-((2-hydroxyethyl)amino)styryl)-6-iodo-4H-chromen-4-one (SC-NHEtOH) and (E)-2-(4-((2-hydroxyethyl)(methyl)amino)styryl)-6-iodo-4H-chromen-4-one (SC-NMeEtOH), respectively. However, none of the VPC derivatives showed binding affinity for the rMoPrP aggregates. Fluorescent imaging demonstrated that the accumulation pattern of SC-NHEtOH matched with the presence of PrP^Sc in the brain slices from mouse-adapted bovine spongiform encephalopathy-infected mice. A biodistribution study of normal mice indicated low initial brain uptake of [¹²⁵I]SC-NHEtOH (0.88% injected dose/g (% ID/g) at 2 min) despite favorable washout from the brain (0.26% ID/g, at 180 min) was displayed. [¹²⁵I]SC-NHEtOH exhibited binding affinities to both artificial prion aggregates as well as prion deposits in the brain. However, significant improvement in the binding affinity for PrP^Sc and blood-brain barrier permeability is necessary for the development of successful in vivo imaging probes for the detection of cerebral PrP^Sc in the brain.

Polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons in five East Asian cities: Seasonal characteristics, health risks, and yearly variations

Total suspended particulate matter and fine particulate matter were collected in five East Asian cities (Sapporo, Sagamihara, Kirishima, Shenyang, and Vladivostok) during warm and cold periods from 2017 to 2018. Nine polycyclic aromatic hydrocarbons (PAHs) and three nitro-polycyclic aromatic hydrocarbons (NPAHs) were detected by high-performance liquid chromatography with a fluorescence detector. The average concentrations of ∑PAHs and ∑NPAHs differed significantly both temporally and spatially and were the lowest in Kirishima during the warm period (∑PAHs: 0.11 ± 0.06 ng m^-3; ∑NPAHs: 1.23 ± 0.96 pg m^-3) and the highest in Shenyang during the cold period (∑PAHs: 49.7 ± 21.8 ng m^-3; ∑NPAHs: 357 ± 180 pg m^-3). The average total benzo[a]pyrene-equivalent concentrations were also higher in Shenyang and Vladivostok than in Japanese cities. According to the results of source apportionment, traffic emissions impacted these cities in both the warm and cold periods, whereas coal combustion-generated effects were obvious in Shenyang and Vladivostok during the cold period. Furthermore, PAHs and NPAHs originating from the Asian continent, including Shenyang and Vladivostok, exerted some influence on Japanese cities, especially in the cold period. Compared to Japanese cities and Vladivostok, yearly variations in ∑PAHs and 1-nitropyrene in Shenyang showed that their concentrations were considerably lower than those reported in past studies, indicating the positive effects of air pollutant control policies in China. These results not only describe the current characteristics and yearly variations of PAHs and NPAHs in typical urban cities in East Asia but also, more importantly, reveal that the effects of the East Asian monsoon play an important role in the analysis of atmospheric behaviours of PAHs and NPAHs. Furthermore, this study supports the role of multinational cooperation to promote air pollution control in East Asia.

Calculating source contributions to urban atmospheric polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons using 1-nitropyrene and pyrene: An application to an Asian dust event

A method to calculate source contributions to atmospheric polycyclic aromatic hydrocarbons (PAHs) and their nitrated congeners (NPAHs) is proposed, using pyrene (Pyr) and 1-nitropyrene (1-NP), as respective representatives of PAHs and NPAHs. This is based on the known increases in NPAH to PAH ratios as combustion temperatures increase. The fractions of 1-NP and Pyr from high temperature combustion sources in total 1-NP and Pyr are respectively calculated as a (0 < a <1) and b (0 < b < 1). By using atmospheric concentrations of Pyr and 1-NP obtained at monitoring sites, contributions of high and low temperature combustion sources were calculated. Using this method, the contributions of automobiles and coal combustion facilities/industries to atmospheric Pyr and 1-NP concentrations were calculated for atmospheric samples collected in Kanazawa, Japan during a seasonal Asian dust event. The results show that Pyr was almost entirely emitted from industries in China and transported long-range to Japan. By contrast, 1-NP was emitted primarily from automobiles in Kanazawa and its surrounding areas, with a small amount of 1-NP possibly transported from China. The proposed method can provide greater clarity on source identification compared to the typically used PAH isomer pairs.

Synthesis and Characterization of Radiogallium-Labeled Cationic Amphiphilic Peptides as Tumor Imaging Agents

SVS-1 is a cationic amphiphilic peptide (CAP) that exhibits a preferential cytotoxicity towards cancer cells over normal cells. In this study, we developed radiogallium-labeled SVS-1 (⁶⁷Ga-NOTA-KV6), as well as two SVS-1 derivatives, with the repeating KV residues replaced by RV or HV (⁶⁷Ga-NOTA-RV6 and ⁶⁷Ga-NOTA-HV6). All three peptides showed high accumulation in epidermoid carcinoma KB cells (53-143% uptake/mg protein). Though ⁶⁷Ga-NOTA-RV6 showed the highest uptake among the three CAPs, its uptake in 3T3-L1 fibroblasts was just as high, indicating a low selectivity. In contrast, the uptake of ⁶⁷Ga-NOTA-KV6 and ⁶⁷Ga-NOTA-HV6 into 3T3-L1 cells was significantly lower than that in KB cells. An endocytosis inhibition study suggested that the three ⁶⁷Ga-NOTA-CAPs follow distinct pathways for internalization. In the biodistribution study, the tumor uptakes were found to be 4.46%, 4.76%, and 3.18% injected dose/g of tissue (% ID/g) for ⁶⁷Ga-NOTA-KV6, ⁶⁷Ga-NOTA-RV6, and ⁶⁷Ga-NOTA-HV6, respectively, 30 min after administration. Though the radioactivity of these peptides in tumor tissue decreased gradually, ⁶⁷Ga-NOTA-KV6, ⁶⁷Ga-NOTA-RV6, and ⁶⁷Ga-NOTA-HV6 reached high tumor/blood ratios (7.7, 8.0, and 3.8, respectively) and tumor/muscle ratios (5.0, 3.3, and 4.0, respectively) 120 min after administration. ⁶⁷Ga-NOTA-HV6 showed a lower tumor uptake than the two other tracers, but it exhibited very low levels of uptake into peripheral organs. Overall, the replacement of lysine in SVS-1 with other basic amino acids significantly influenced its binding and internalization into cancer cells, as well as its in vivo pharmacokinetic profile. The high accessibility of these peptides to tumors and their ability to target the surface membranes of cancer cells make radiolabeled CAPs excellent candidates for use in tumor theranostics.

Characteristics and unique sources of polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons in PM2.5 at a highland background site in northwestern China☆

Polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) in PM_2.5 were first observed at a background site (Yuzhong site: YZ site) in the northwestern highlands of China in five seasonal campaigns. Compared with major northwestern cities, PAHs and NPAHs at the YZ site were at a lower level but showed consistent seasonal differences. The PAH and NPAH concentrations peaked in the winter campaigns, which were 36.11 ± 6.54 ng/m³ and 418.11 ± 123.55 pg/m³, respectively, in winter campaign 1 and 28.97 ± 10.07 ng/m³ and 226.89 ± 133.54 pg/m³, respectively, in winter campaign 2. These values were approximately a dozen times larger those in other campaigns. The diagnostic ratios indicate that vehicle emissions were the primary source of the PAHs throughout the five campaigns, and coal and biomass combustion also contributed during the winter, summer, and fall campaigns. Among NPAHs, 2-nitrofluoranthene and 2-nitropyrene were generated through OH radical-initiated reactions during atmospheric transport, while 1-nitropyrene came from combustion sources. There is an observation worth pondering, which is that the ratio between pyrene and fluoranthene increased abnormally in the spring and fall campaigns, which is presumably caused by the burning of Tibetan barley straw in the northwestern highlands. The backward trajectories over Tibetan areas in Qinghai and southwestern Gansu are consistent with this hypothesis. In addition, this study reported for the first time that the burning of Tibetan barley straw has become a seasonal contributor to air pollution in northwestern China and is participating in the atmospheric transport of air pollutants driven by the monsoon in East Asia, which urgently requires further research.

Characteristics and Health Risks of Polycyclic Aromatic Hydrocarbons and Nitro-PAHs in Xinxiang, China in 2015 and 2017

Fine particulate matter (PM_2.5) samples were collected in the summer and winter of 2015 and 2017 in Xinxiang, China. Nine polycyclic aromatic hydrocarbons (PAHs) and three nitro-PAHs (NPAHs) in PM_2.5 were detected via high-performance liquid chromatography (HPLC). The PAHs concentration in summer and winter decreased from 6.37 ± 1.30 ng/m³ and 96.9 ± 69.9 ng/m³ to 4.89 ± 2.67 ng/m³ and 49.8 ± 43.4 ng/m³ from 2015 to 2017. NPAHs decreased in winter (from 1707 ± 708 pg/m³ to 1192 ± 1113 pg/m³), but increased in summer from 2015 (336 ± 77.2 pg/m³) to 2017 (456 ± 312 pg/m³). Diagnostic ratios of PAHs indicated that petroleum combustion was the main emission source in summer, and pollutants originating from the combustion of petroleum, coal and biomass dominated in winter. The 2-nitrofluoranthene (2-NFR)/2-nitropyrene (2-NP) ratio in this study demonstrated that the OH radical pathway was the main pathway for the formation of 2-NP and 2-NFR. The mean total benzo[a]pyrene-equivalent concentrations (BaP_eq) and incremental lifetime cancer risk (ILCR) values decreased from 2013 to 2017. The high value of total BaPeq in the winter of 2017 in Xinxiang revealed that a high-risk of cancer remained for residents. The results of this study demonstrate that the decreases in PAHs and NPAHS concentrations from 2015 to 2017. Combined with reducing gaseous pollutants concentration, the reduction in this study might be attributable to emissions reductions by implementing the air pollution control regulations in Xinxiang city in 2016.

Long-term variability of inorganic ions in TSP at a remote background site in Japan (Wajima) from 2005 to 2015

Eleven years (2005-2015) of data from long-term monitoring at a Japanese remote background site in Wajima, were analyzed to investigate temporal trends and sources. Water-soluble inorganic ions (WSIIs) were analyzed for aerosol chemical composition. The total WSIIs concentration was 7.93 ± 3.93 μg/m³, accounting for 42.3% of TSP mass, ranged from 11.4 to 93.9%. SO₄^2- is the most abundant ion, contributing a total WSII mass from 18.0 to 79.8%, and non-sea-salt (nss-) SO₄^2- contributed from 63.6% to 99.6% of total SO₄^2-, which was related to human activities on the Asian continent and the effects of marine precursors in spring and summer, respectively. NO₃^- and NH₄⁺ contribute 6.3 and 7.4% of the total WSIIs and were affected by long-range transport and local sources as well. The increasing trend of Na⁺ and Cl^- indicates the increased influence of sea salt, which is caused by more frequent strong winds. K⁺ is mainly produced from biomass burning with a stable seasonal variation, Ca²⁺ as the characteristic ion of dust has the highest concentration in spring. Mg²⁺ comes from minerals and marine sources during spring and summer, respectively. This work describes in detail the annual change trend of the WSIIs of atmospheric particles in the Wajima area, seasonal characteristics, and source contributions, provide a comprehensive understanding of long-term variation in atmospheric particulate.

Atmospheric Behaviour of Polycyclic and Nitro-Polycyclic Aromatic Hydrocarbons and Water-Soluble Inorganic Ions in Winter in Kirishima, a Typical Japanese Commercial City

Kirishima is a typical Japanese commercial city, famous for frequent volcanic activity. This is the first study to determine the characteristics of PM2.5-bound polycyclic and nitro-polycyclic aromatic hydrocarbons (PAHs and NPAHs) and water-soluble inorganic ions (WSIIs) in this city. In this study, the non-volcanic eruption period was taken as the target and daily PM2.5 samples were collected from 24 November to 21 December 2016. The daily concentrations in PM2.5 of ƩPAHs, ƩNPAHs, and ƩWSIIs ranged from 0.36 to 2.90 ng/m3, 2.12 to 22.3 pg/m3, and 1.96 to 11.4 μg/m3, respectively. Through the results of the diagnostic ratio analyses of the PAHs, NPAHs, and WSIIs and the backward trajectory analysis of the air masses arriving in Kirishima, the emission sources of PAHs, NPAHs, and WSIIs in PM2.5 in Kirishima were influenced by the coal burning that came from the East Asian continent, although there was no influence from volcanic emission sources during the sampling period. The total benzo[a]pyrene (BaP)-equivalent concentration was lower than many other cities but the health risks in Kirishima were nonetheless notable. These findings are very important for future research on PM samples during the inactive Asian monsoon and volcanic eruption periods, to further understand the characteristics of air pollutants in Kirishima, and to contribute to the improvement in health of residents and a reduction in the atmospheric circulation of air pollutants in East Asia.

Yearly variation in characteristics and health risk of polycyclic aromatic hydrocarbons and nitro-PAHs in urban shanghai from 2010-2018

This study encompassed the regular observation of nine polycyclic aromatic hydrocarbons (PAHs) and three nitro-PAHs (NPAHs) in particulate matter (PM) in Shanghai in summer and winter from 2010 to 2018. The results showed that the mean concentrations of ƩPAHs in summer decreased by 24.7% in 2013 and 18.1% in 2017 but increased by 10.2% in 2015 compared to the data in 2010. However, the mean concentrations of ƩPAHs in winter decreased by 39.7% from 2010 (12.8 ± 4.55 ng/m³) to 2018 (7.72 ± 3.33 ng/m³), and the mean concentrations of 1-nitropyrene in winter decreased by 79.0% from 2010 (42.3 ± 16.1 pg/m³) to 2018 (8.90 ± 2.09 pg/m³). Correlation analysis with meteorological conditions revealed that the PAH and NPAH concentrations were both influenced by ambient temperature. The diagnostic ratios of PAHs and factor analysis showed that they were mainly affected by traffic emissions with some coal and/or biomass combustion. The ratio of 2-nitrofluoranthene to 2-nitropyrene was near 10, which indicated that the OH radical-initiated reaction was the main pathway leading to their secondary formation. Moreover, backward trajectories revealed different air mass routes in each sampling period, indicating a high possibility of source effects from the northern area in winter in addition to local and surrounding influences. Meanwhile, the mean total benzo[a]pyrene-equivalent concentrations in Shanghai in winter decreased by 50.8% from 2010 (1860 ± 645 pg/m³) to 2018 (916 ± 363 pg/m³). These results indicated the positive effects of the various policies and regulations issued by Chinese authorities.

What is necessary for next-generation atmospheric environmental standards? Recent research trends for PM2.5 -bound polycyclic aromatic hydrocarbons and their derivatives

The air pollution associated with PM_2.5 kills 7 million people every year in the world, especially threatening the health of children in developing countries. However, the current air quality standards depend mainly on particle size. PM_2.5 contains many carcinogenic/mutagenic polycyclic aromatic hydrocarbons (PAHs) and their derivatives such as nitropolycyclic aromatic hydrocarbons and oxygenated PAHs. Among them, environmental standards and guidelines have been set for benzo[a]pyrene by few countries and international organizations. Recent research reports showed that these pollutants are linked to diseases other than lungs, and new methods have been developed for determining trace levels of not only PAHs but also their derivatives. It is time to think about the next-generation environmental standards. This article aims to (a) describe recent studies on the health effects of PAHs and their derivatives other than cancer, (b) describe new analytical methods for PAH derivatives, and (c) discuss the targets for the next-generation standards.

Comparative Analysis of PM2.5-Bound Polycyclic Aromatic Hydrocarbons (PAHs), Nitro-PAHs (NPAHs), and Water-Soluble Inorganic Ions (WSIIs) at Two Background Sites in Japan

Daily PM2.5 (particulate matter with aerodynamic diameter ≤2.5 μm) samples were simultaneously collected at two background sites (Wajima Air Monitoring Station (WAMS) and Fukue-Jima Atmosphere and Aerosol Monitoring Station (FAMS)) in Japan in the East Asian winter and summer monsoon periods of 2017 and 2019, to compare the characteristics of air pollutants among different regions and to determine the possible variation during the long-range transport process. Polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and water-soluble inorganic ions (WSIIs) were analyzed. Despite the PM2.5 concentrations at FAMS (8.90-78.5 µg/m3) being higher than those at WAMS (2.33-21.2 µg/m3) in the winter monsoon period, the average concentrations of ∑PAHs, ∑NPAHs, and ∑WSIIs were similar between the two sites. Diagnostic ratios indicated PAHs mainly originated from traffic emissions and mostly aged, whereas NPAHs were mostly secondarily formed during long-range transport. WSIIs at WAMS were mainly formed via the combustion process and secondary reactions, whereas those at FAMS mainly originated from sea salt and dust. Backward trajectories revealed the air masses could not only come from Asian continental coastal regions but also distant landlocked areas in the winter monsoon period, whereas most came from the ocean in the summer monsoon period. These findings can provide basic data for the establishment of prediction models of transboundary air pollutants in East Asia.

Calculating sources of combustion-derived particulates using 1-nitropyrene and pyrene as markers

Airborne particulate matter (PM) contains numerous hazardous polycyclic aromatic hydrocarbons (PAHs) as well as their functionalized congeners. However, the lack of useful methods to identify the sources of PM has hindered the development of researches in atmospheric and public health fields. This report proposes a new method for estimating the source contribution of combustion-derived particulate (P_c) by using 1-nitropyrene (1-NP) and pyrene (Pyr) as markers. This is premised on the fact that the formation of nitrogen oxides in the flame gas and the subsequent nitration of PAHs are functions of combustion temperature and therefore the concentration ratios of NPAHs to PAHs are highly temperature dependent. This method divides combustion sources into two groups - high and low temperatures - which here are respectively represented by automobile engine and coal combustion in urban areas. Formulae are derived for combustion-derived particulate (P_c), whose fraction in the total particulate is y (0 < y < 1), and particulates from combustion sources with high temperatures (P_h), whose fraction in P_c is x (0 < x < 1), and low temperatures (P_l), whose fraction is (1 －x). When concentrations of 1-NP and Pyr in P_h and P_l are known, values x and y can be calculated from the formulae by determining atmospheric 1-NP and Pyr concentrations at monitoring sites. Then atmospheric concentrations of P_c, P_h and P_l can be calculated. The proposed method has been applied for total suspended particulate matter (TSP) samples collected in Kanazawa and Kitakyushu (Japan) and Beijing (China) having different types of atmospheric pollution to clarify the change of contributions of automobiles and coal combustion.

Natural aeolian dust particles have no substantial effect on atmospheric polycyclic aromatic hydrocarbons (PAHs): A laboratory study based on naphthalene

Natural aeolian dust (AD) particles are potential carriers of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. The heterogeneous interaction between them may lead to worsened air quality and enhanced cytotoxicity and carcinogenicity of ambient particulates in downwind areas, and this topic requires in-depth exploration. In this study, AD samples were collected from four Asian dust sources, and their physical properties and compositions were determined, showing great regional differences. The physical and chemical interactions of different AD particles with naphthalene (Nap; model PAH) were observed in aqueous systems. The results showed that AD particles from the Loess Plateau had weak adsorption to Nap, which was fitted by the Langmuir isotherm. There was no obvious adsorption to Nap found for the other three AD samples. This difference seemed to depend mainly on the specific surface area and/or the total pore volume. In addition, the Nap in the aqueous solution did not undergo chemical reactions under dark conditions and longwave ultraviolet (UV) radiation but degraded under shortwave UV radiation, and 2-formylcinnamaldehyde and 1,4-naphthoquinone were the first-generated products. The degradation of Nap in the aqueous solution was probably initiated by photoionization, and the reaction rate constant (between 1.44 × 10^-4 min^-1 and 8.55 × 10^-4 min^-1) was much lower than that of Nap with hydroxyl radicals. Instead of inducing or promoting the chemical change in Nap, the AD particles slowed photodegradation due to the extinction of radiation. Therefore, it is inferred that natural AD particles have no substantial effect on the transportation and transformation of PAHs in the atmosphere.

PM2.5-bound polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons inside and outside a primary school classroom in Beijing: Concentration, composition, and inhalation cancer risk

PM_2.5 samples were collected inside and outside a primary school classroom in Beijing in 2015 and analysed for 11 polycyclic aromatic hydrocarbons (PAHs) and 10 nitro-PAHs (NPAHs). In the sampling period in the heating season (namely, the heating period), the median concentrations of indoor and outdoor PAHs were 223 ng/m³ and 264 ng/m³, respectively, and those of indoor and outdoor NPAHs were 3.61 ng/m³ and 5.12 ng/m³, respectively. The concentrations of PAHs and NPAHs were consistently higher in the heating period than those (indoor PAHs: 8.75 ng/m³, outdoor PAHs: 8.95 ng/m³, indoor NPAHs: 0.25 ng/m³, outdoor NPAHs: 0.40 ng/m³) in the sampling period in the non-heating season (namely, the non-heating period). In both periods, total PAHs and total NPAHs in indoor PM_2.5, as well as most individual PAHs and NPAHs, were positively correlated with the outdoor PAH and NPAH concentrations (p < 0.05). This finding suggests that indoor PAHs and NPAHs are largely dependent on outdoor inputs. It is inferred from the diagnostic ratios that PAHs and NPAHs in indoor and outdoor PM_2.5 were affected jointly by coal combustion and vehicular emission in the heating period and mainly derived from vehicle exhaust in the non-heating period. Both indoor and outdoor PM_2.5 showed considerable benzo[a]pyrene equivalent toxicity (BaP_eq), especially in the heating period. Benzo[c]fluorene (BcFE) had relatively low concentrations but large contributions to BaP_eq in both periods. This is the first report of PM_2.5-bound BcFE inside and outside classrooms in Beijing. This result indicates that neglecting PAHs with low abundance but high toxicity leads to a significant underestimation of the overall PAH toxicity. The inhalation cancer risk (CR) of PAHs and NPAHs in PM_2.5 during the primary school year exceeded the acceptable level as defined by the U.S. EPA, emphasizing its impact on the lifetime CR in schoolchildren.

Size distribution of particulate polycyclic aromatic hydrocarbons in fresh combustion smoke and ambient air: A review

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the atmosphere and they mostly stem from the imperfect combustion of fossil fuels and biofuels. PAHs are inherently associated with homogenous fine particles or distributed to different-sized particles during the aging of air masses. PAHs carried by fine particles undergo a long-range transport to remote areas while those adsorbed on coarse particles have a shorter lifetime in ambient air. More importantly, PAHs with higher molecular weights tend to be bound with finer particles and can deeply enter the lungs, posing severe health risks to humans. Thus, the environmental fate and health effects of particulate PAHs are strongly size-dependent. This review summarizes the size distributions of particulate PAHs freshly emitted from combustion sources as well as the distribution patterns of PAHs in ambient particles. It was found that PAHs from stationary sources are primarily bound to fine particles, which are slightly larger than particles to which PAHs from mobile sources are bound. In ambient air, particulate PAHs are distributed in larger size modes than those in the combustion fume, and the particle size decreases with PAH molecular weight increasing. The relevant mechanisms and influencing factors of particle size distribution changes are illustrated in this article, which are essentially attributed to combustion and ambient temperature as well as the physical and chemical properties of PAHs. Overall, the study on the particle size distribution of PAHs will contribute for a full understanding of the origin, atmospheric behaviors and health effects of particulate PAHs.

Characteristics of air pollutants inside and outside a primary school classroom in Beijing and respiratory health impact on children

This study investigated the spatial and temporal distributions of particulate and gaseous air pollutants in a primary school in Beijing and assessed their health impact on the children. The results show that air quality inside the classroom was greatly affected by the input of outdoor pollutants; high levels of pollution were observed during both the heating and nonheating periods and indicate that indoor and outdoor air pollution posed a threat to the children's health. Traffic sources near the primary school were the main contributors to indoor and outdoor pollutants during both periods. Moreover, air quality in this primary school was affected by coal combustion and atmospheric reactions during the heating and nonheating periods, respectively. Based on the estimation by exposure-response functions and the weighting of indoor and outdoor pollutants during different periods, the levels of PM_2.5, PM ₁₀ and O₃ at school had adverse respiratory health effects on children. Longer exposures during the nonheating period contributed to higher health risks. These results emphasized that emission sources nearby had a direct impact on air quality in school and children's respiratory health. Therefore, measures should be taken for double control on air pollution inside and outside the classroom to protect children from it.

Investigation of inflammation inducing substances in PM2.5 particles by an elimination method using thermal decomposition

The substances associated with PM2.5-induced inflammatory response were investigated using an elimination method. PM2.5 were heated at temperatures of 120, 250, and 360°C. The results demonstrated microbial substances such as LPS and b-glucan, and chemicals including BaP, 1,2-NQ, and 9,10-PQ were reduced drastically in PM2.5 heated at 120°C. On the other hand, DBA, 7,12-BAQ, and BaP-1,6-Q were not noticeably reduced. Most of these substances had disappeared in PM2.5 heated at 250°C and 360°C. Metals (eg, Fe, Cu, Cr, Ni) in PM2.5 exhibited a slight thermo-dependent increase. RAW264.7 macrophages with or without NAC were exposed to unheated PM2.5, oxidative stress-related and unrelated inflammatory responses were induced. PM2.5-induced lung inflammation in mice is caused mainly by thermo-sensitive substances (LPS, b-glucan, BaP, 1,2-NQ, 9,10-PQ, etc.). Also, a slight involvement of thermo-resistant substances (DBA, 7,12-BAQ, BaP-1,6-Q, etc.) and transition metals was observed. The thermal decomposition method could assist to evaluate the PM2.5-induded lung inflammation.

The Characteristics of Polycyclic Aromatic Hydrocarbons in Different Emission Source Areas in Shenyang, China

Particulate matter (PM) was collected in three different areas, SY-1, SY-2, and SY-3, in Shenyang, China, during the warm and cold seasons from 2012 to 2014. SY-1 was located beside a thermal power plant, far from the central area. SY-2 was near a coal heating boiler on the main road, close to the central area. SY-3 was on the main road, without fixed emission sources. Nine PM-bound polycyclic aromatic hydrocarbons (PAHs) were analyzed. The results showed that the mean concentration of total PAHs was higher in the cold season (92.6-316 ng m-3) than in the warm season (18.4-32.2 ng m-3). Five- and six-ring PAHs occupied a large percentage at all sites in the warm season, and four-ring PAHs were the dominant components in the cold season. Several diagnostic PAH ratios indicated that the main sources of PAHs in Shenyang in the warm and cold seasons were not only coal burning but also vehicle emission. In this study, we suggest that a benzo[a]pyrene/benzo[ghi]perylene ratio ([BaP]/[BgPe]) of 0.6 was a useful indicator to speculate the relative significance of coal burning and vehicle exhaust. Although the Shenyang government has undertaken actions to address air pollution, the PM and PAH concentrations did not decrease significantly compared to those in our previous studies. The cancer risk calculated from the BaP equivalent total concentration at all three sites in the warm and cold seasons exceeded the acceptable limit established by the US EPA.

Emission Characteristics of Polycyclic Aromatic Hydrocarbons and Nitro-Polycyclic Aromatic Hydrocarbons from Open Burning of Rice Straw in the North of Vietnam

This research investigated the distribution and contribution of polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) bound to particulate matter (PM) emitted from open burning of rice straw (RS) into the atmosphere in the north of Vietnam. The experiments were conducted to collect PM_2.5 and total suspended particulates (TSP) prior to and during burning in the period of 2016–2018 in suburban areas of Hanoi. Nine PAHs and 18 NPAHs were determined using the HPLC-FL system. The results showed that the proportion of RS burning seasonally affects the variation of PAHs emission in atmospheric environment. The levels of nine PAHs from RS burning were 254.4 ± 87.8 µg g⁻¹ for PM_2.5 and 209.7 ± 89.5 µg g⁻¹ for TSP. We observed the fact that, although fluoranthene (Flu) was the most abundant PAH among detected PAHs both in PM_2.5 and TSP, the enrichment of Flu in TSP from burning smoke was higher than that in PM_2.5 while the contribution of benzo[a]pyrene (BaP) and indeno[1,2,3- cd]pyrene (IDP) in PM_2.5 from burning smoke were much higher than those in TSP. This research found that 1-nitropyrene (1-NP) and 6-nitrochrysene (6-NC) emit from RS burning with the same range with those from wood burning. The 2-nitrofluorene (2-NF) and 2-nitropyrene (2-NP) released from RS burning as the secondary NPAHs. This research provides a comprehensive contribution characterization of PAHs and NPAHs in PM with different size emitted from traditional local rice straw burning in the north of Vietnam. The results help to clarify the environmental behavior of toxic organic compounds from RS burning in Southeast Asia.

Long term trends in atmospheric concentrations of polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons: A study of Japanese cities from 1997 to 2014

Total suspended particulate matter (TSP) was collected during the summer and winter in five Japanese cities spanning Hokkaido to Kyushu (Sapporo, Kanazawa, Tokyo, Sagamihara and Kitakyushu) from 1997 to 2014. Nine polycyclic aromatic hydrocarbons (PAHs) with four to six rings, including pyrene (Pyr) and benzo[a]pyrene (BaP), were identified using high-performance liquid chromatography (HPLC) with fluorescence detection. Two nitropolycyclic aromatic hydrocarbons (NPAHs), 1-nitropyrene (1-NP) and 6-nitrobenzo[a]pyrene (6-NBaP), were identified by HPLC with chemiluminescence detection. A comparison of PAH and NPAH concentrations and [NPAH]/[PAH] ratios such as [1-NP]/[Pyr] and [6-NBaP]/[BaP] revealed the following characteristics in the five cities: (1) In Sapporo, Kanazawa, Tokyo and Sagamihara, the concentrations of PAHs and NPAHs were high at the beginning of the sampling period and then steadily decreased, with NPAHs decreasing faster than PAHs. The large initial [1-NP]/[Pyr] ratios suggest that the major contributor was automobiles but subsequent decreases in this ratio suggest decreased automobile contributions. (2) By contrast, PAH concentrations in Kitakyushu did not decrease during the sampling period, though concentrations of NPAHs decreased. The consistently smaller [1-NP]/[Pyr] ratio and larger [6-NBaP]/[BaP] ratio in Kitakyushu suggests that the major contributor of PAHs was not automobiles but iron manufacturing which uses a large amount of coal. The sudden increase in atmospheric PAH concentrations in the winter of 2014 may also be due to iron manufacturing.

Persistent organic pollutants in red-crowned cranes (Grus japonensis) from Hokkaido, Japan

The red-crowned crane (Grus japonensis) from eastern Hokkaido is classified as a Special Natural Monument in Japan. In this study, we determined the concentrations of persistent organic pollutants (POPs) in red-crowned crane muscle tissues (n = 47). Polychlorinated biphenyls (PCBs) had the highest median concentration (240ng/g lipid weight), followed by dichlorodiphenyltrichloroethane and its metabolites (DDTs) (150ng/g lipid weight), chlordane-related compounds (CHLs) (36ng/g lipid weight), hexachlorobenzene (HCB) (16ng/g lipid weight), hexachlorocyclohexanes (HCHs) (4.4ng/g lipid weight), polybrominated diphenyl ethers (PBDEs) (1.8ng/g lipid weight), and finally, Mirex (1.5ng/g lipid weight). Additionally, a positive correlation was found among POP concentrations. No sex differences beyond body parameters were observed. Additionally, red-crowned cranes exhibited a high enantiomeric excess of (+)-alpha-HCH, with enantiomer fractions varying from 0.51 to 0.87 (average: 0.69).

Personal inhalation exposure to polycyclic aromatic hydrocarbons and their nitro-derivatives in rural residents in northern Thailand

A personal inhalation exposure and cancer risk assessment of rural residents in Lampang, Thailand, was conducted for the first time. This highlighted important factors that may be associated with the highest areal incidence of lung cancer. Personal exposure of rural residents to polycyclic aromatic hydrocarbons (PAHs) and their nitro-derivatives (NPAHs) through inhalation of fine particulate matter (PM_2.5) was investigated in addition to stationary air sampling in an urban area. The personal exposure of the subjects to PM_2.5 ranged from 44.4 to 316 μg/m³, and the concentrations of PAHs (4.2-224 ng/m³) and NPAHs (120-1449 pg/m³) were higher than those at the urban site, indicating that personal exposure was affected by microenvironments through individual activities. The smoking behaviors of the rural residents barely affected their exposure to PAHs and NPAHs compared to other sources. The most important factor concerning the exposure of rural populations to PAHs was cooking activity, especially the use of charcoal open fires. The emission sources for rural residents and urban air were evaluated using diagnostic ratios, 1-nitropyrene/pyrene, and benzo[a]pyrene/benzo[ghi]perylene. Their analyses showed a significant contribution to emission from residents' personal activities in addition to the atmospheric environment. Furthermore, the personal inhalation cancer risks for all rural subjects exceeded the USEPA guideline value, suggesting that the residents have a potentially increased cancer risk. The use of open fires showed the highest cancer risk. A reduction in exposure to air pollutants for the residents could potentially be achieved by using clean fuel such as liquid petroleum gas or electricity for daily cooking.

Seawater Polluted with Highly Concentrated Polycyclic Aromatic Hydrocarbons Suppresses Osteoblastic Activity in the Scales of Goldfish, Carassius auratus

We have developed an original in vitro bioassay using teleost scale, that has osteoclasts, osteoblasts, and bone matrix as each marker: alkaline phosphatase (ALP) for osteoblasts and tartrate-resistant acid phosphatase (TRAP) for osteoclasts. Using this scale in vitro bioassay, we examined the effects of seawater polluted with highly concentrated polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) on osteoblastic and osteoclastic activities in the present study. Polluted seawater was collected from two sites (the Alexandria site on the Mediterranean Sea and the Suez Canal site on the Red Sea). Total levels of PAHs in the seawater from the Alexandria and Suez Canal sites were 1364.59 and 992.56 ng/l, respectively. We were able to detect NPAHs in both seawater samples. Total levels of NPAHs were detected in the seawater of the Alexandria site (12.749 ng/l) and the Suez Canal site (3.914 ng/l). Each sample of polluted seawater was added to culture medium at dilution rates of 50, 100, and 500, and incubated with the goldfish scales for 6 hrs. Thereafter, ALP and TRAP activities were measured. ALP activity was significantly suppressed by both polluted seawater samples diluted at least 500 times, but TRAP activity did not change. In addition, mRNA expressions of osteoblastic markers (ALP, osteocalcin, and the receptor activator of the NF-κB ligand) decreased significantly, as did the ALP enzyme activity. In fact, ALP activity decreased on treatment with PAHs and NPAHs. We conclude that seawater polluted with highly concentrated PAHs and NPAHs influences bone metabolism in teleosts.

Size Distribution of Chlorinated Polycyclic Aromatic Hydrocarbons in Atmospheric Particles

The particle size distribution of chlorinated polycyclic aromatic hydrocarbons (ClPAHs) in particulate matter (PM) in Japan is examined for the first time. PM was collected using a PM_0.1 air sampler with a six-stage filter. PM was collected in October 2014 and January 2015 to observe potential seasonal variation in the atmospheric behavior and size of PM, including polycyclic aromatic hydrocarbons (PAHs) and ClPAHs. We found that the concentration of PAHs and ClPAHs between 0.5-1.0 μm and 1.0-2.5 μm markedly increase in January (i.e., the winter season). Among the ClPAHs, 1-ClPyrene and 6-ClBenzo[a]Pyrene were the most commonly occurring compounds; further, approximately 15% of ClPAHs were in the nanoparticle phase (<0.1 μm). The relatively high presence of nanoparticles is a potential human health concern because these particles can easily be deposited in the lung periphery. Lastly, we evaluated the aryl hydrocarbon receptor (AhR) ligand activity of PM extracts in each size fraction. The result indicates that PM < 2.5 μm has the strong AhR ligand activity.

Comparison of Air Pollution in Metropolises in China (Beijing) and Japan (Osaka and Nagoya) on the Basis of the Levels of Contaminants and Mutagenicity

Public concern regarding the transport of air pollutants from mainland East Asia to the leeward area by the prevailing westerlies in spring and winter monsoon has been growing in recent years. We collected total suspended particle (TSP) in Beijing, a metropolis of China located windward of Japan, in spring (late February 2011-May 2011) and in winter (November 2012-early February 2013), then analyzed metals, ions, and organic compounds and mutagenicity, and compared the pollution levels with samples collected at two Japanese metropolises (Osaka and Nagoya) during the same periods. The medians of concentration of TSP and other factors in Beijing were much larger than those in the Japanese metropolises. Especially, the concentrations of polycyclic aromatic hydrocarbons (PAHs) were remarkably high in Beijing in winter, and the median of total PAHs concentration in Beijing was 62-63 times larger than that in the Japanese sites. The mutagenicity of TSP from Beijing toward Salmonella typhimurium YG1024, with and without a mammalian metabolic system (S9 mix), was 13-25 times higher than that from the Japanese sites in winter. These results suggest that air pollution levels in Beijing are very high compared with those at the two Japanese metropolises we evaluated. The diagnostic ratios of PAHs and nitrated polycyclic aromatic hydrocarbons (NPAHs) suggest that the major sources of PAHs and NPAHs in Beijing are different from those at the two Japanese sites in winter, and that the major source in Beijing is coal/biomass combustion.

Nitro-PAH exposures of occupationally-exposed traffic workers and associated urinary 1-nitropyrene metabolite concentrations

The assessment of occupational exposure to diesel exhaust (DE) is important from an epidemiological perspective. Urinary biomarkers of exposure have been proposed as a novel approach for measuring exposure to DE. In this study, we measured the concentrations of two urinary metabolites of 1-nitropyrene (1NP), a nitrated polycyclic aromatic hydrocarbon that has been suggested as a molecular marker of diesel particulate matter. These two metabolites, 6-hydroxy-1-nitropyrene and 8-hydroxy-1-nitropyrene, were determined in urine samples (10mL) from a small group of workers who were occupationally-exposed to vehicle exhaust in Trujillo, Peru, before and after their workshifts. Workshift exposures to 1NP, as well as PM_2.5, 2-nitropyrene and 2-nitrofluoranthene, were also measured. Exposures to 1NP were similar in all studied workers, averaging 105±57.9pg/m³ (±standard deviation). Median urinary concentrations of the average of the pre- and post-exposure samples for 6-hydroxy-1-nitropyrene and 8-hydroxy-1-nitropyrene, were found to be 3.9 and 2.3pgmetabolite/mg creatinine, respectively in the group of occupationally-exposed subjects (n=17) studied. A direct relationship between workshift exposure to 1NP and urinary 1NP metabolites concentrations was not observed. However, the 1NP exposures and the creatinine-corrected urinary concentrations of the hydroxynitropyrene metabolites in these Peruvian traffic workers were similar to occupationally-exposed taxi drivers in Shenyang, China, and were higher than biomarker levels in office workers from Trujillo without occupational exposure to vehicle exhaust. This study provides further evidence that urinary metabolites of 1NP are associated with exposure to DE and may serve as a useful exposure biomarker.

Mineral dust aerosols promote the formation of toxic nitropolycyclic aromatic compounds

Atmospheric nitrated polycyclic aromatic hydrocarbons (NPAHs), which have been shown to have adverse health effects such as carcinogenicity, are formed in part through nitration reactions of their parent polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. However, little is known about heterogeneous nitration rates of PAHs by gaseous NO2 on natural mineral substrates, such as desert dust aerosols. Herein by employing kinetic experiments using a flow reactor and surface analysis by Fourier transform infrared spectroscopy with pyridine adsorption, we demonstrate that the reaction is accelerated on acidic surfaces of mineral dust, particularly on those of clay minerals. In support of this finding, we show that levels of ambient particle-associated NPAHs in Beijing, China, significantly increased during heavy dust storms. These results suggest that mineral dust surface reactions are an unrecognized source of toxic organic chemicals in the atmosphere and that they enhance the toxicity of mineral dust aerosols in urban environments.

Spatial correlativity of atmospheric particulate components simultaneously collected in Japan

The simultaneous sampling of total suspended particles was performed at 14 sites in Japan during July 2008-June 2009. The spatial correlativity of each particulate composition toward Osaka was obtained for nine selected sites to overview the chemical composition and geographical distribution of particulate components across a wide range of areas nationwide. The spatial correlatives of atmospheric particulate components were extended to an even wider range of areas up to 950 km distance (meso-alpha scale region, >200 km) for a far-reaching distance analysis unique in the literature. Overall, the spatial correlations of ionic species and both organic and elemental carbons were significant, suggesting their shared advections, including their long-range transport from East Asia. Although sulfate ions are widely dispersed across Japan, such is not necessarily correlated with organic and elemental carbon, possibly indicating that the sulfate emission source, including long-range transport, differs from that of carbonaceous particulates. By contrast, the characteristics of spatial correlatives of metallic constituents vary; for example, particulate Pb and Cd show a significantly wide range of spatial correlatives to Osaka, while Mn-though limited to cities neighboring Osaka-shows significant spatial correlations. Other metallic constituents showed no significant spatial correlatives, indicating the effects of local pollutants. Moreover, the extent of the spatial dispersion of the particulate components and the relationships among chemical components were analyzed via factor analysis to highlight the effects of long-range inflow and local original emissions. In this treatment, 13 particulate components among the 19 measured were implicated in long-range transport.

Dechlorane Plus and decabromodiphenyl ether in atmospheric particles of northeast Asian cities

Atmospheric particles were collected in several cities in Japan (Sapporo, Sagamihara, Kanazawa, and Kitakyushu), Korea (Busan), and China (Beijing) using a high-volume air sampler equipped with a quartz fiber filter. The summer and winter samples were analyzed using gas chromatography-high-resolution mass spectrometry for Dechlorane Plus (DP). Decabromodiphenyl ether (BDE-209) was also analyzed for the samples from Kanazawa and Beijing. DP was detected in all samples. The mean total DP (ΣDP) concentration was highest (6.7 pg/m(3)) and lowest (0.87 pg/m(3)) in the winter samples from Sagamihara and Busan, respectively. The seasonal variation of DP concentrations varied by sampling site in this study. BDE-209 was detected in all the analyzed samples except for one of the Kanazawa winter samples. BDE-209 concentration was considerably higher in Beijing than in Kanazawa. Significant correlations were found between the concentrations of ΣDP and BDE-209 in the winter samples from Kanazawa and in both summer and winter samples from Beijing. This similarity in the atmospheric behavior of DP and BDE-209, especially in winter, is assumed to reflect a common end usage and release mechanism.

Identification and characterization of oxidative metabolites of 1-chloropyrene

Polycyclic aromatic hydrocarbons (PAHs) and chlorinated PAHs (ClPAHs) are ubiquitous contaminants that bind to the aryl hydrocarbon receptor (AhR) and exhibit mutagenic potential. It is difficult to monitor human exposure levels to ClPAHs because the exposure routes are complicated, and environmental concentrations are not always correlated with the levels of PAHs. Urinary PAH metabolites are useful biomarkers for evaluating PAH exposure, and ClPAH metabolites may therefore contribute to the estimation of ClPAH exposure. One of the most abundant ClPAHs present in the environment is 1-chloropyrene (ClPyr), and urinary ClPyr metabolites have the potential to be good biomarkers to evaluate the level of exposure to ClPAHs. Since the metabolic pathways involving ClPAHs are still undetermined, we investigated the effect of human cytochrome P450 enzymes on ClPyr and identified three oxidative metabolites by liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance. We found that ClPyr was metabolized most efficiently by the P450 1A1 enzyme, followed by the 1B1 and 1A2 enzymes. Similar to ClPyr, these metabolites were shown to have agonist activity for the human AhR. We detected these metabolites when ClPyr reacted with a pooled human liver S9 fraction as well as in human urine samples. These results suggest that the metabolites may be used as biomarkers to evaluate the extent of exposure to ClPAHs.

A method for simultaneous determination of 20 Fusarium toxins in cereals by high-resolution liquid chromatography-Orbitrap mass spectrometry with a pentafluorophenyl column

A high-resolution liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap MS) method was developed for simultaneous determination of 20 Fusarium toxins (nivalenol, fusarenon-X, deoxynivalenol, 3-acetyl deoxynivalenol, 15-acetyl deoxynivalenol, HT-2 toxin, T-2 toxin, neosolaniol, diacetoxyscirpenol, fumonisin B1, fumonisin B2, fumonisin B3, fumonisin A1, fumonisin A2, fumonisin A3, zearalenone, α-zearalenol, β-zearalenol, α-zearalanol, and β-zearalanol) in cereals. The separation of 20 Fusarium toxins with good peak shapes was achieved using a pentafluorophenyl column, and Orbitrap MS was able to detect accurately from cereal matrix components within ±0.77 ppm. The samples were prepared using a QuEChERS kit for extraction and a multifunctional cartridge for purification. The linearity, repeatability, and recovery of the method were >0.9964, 0.8%-14.7%, and 71%-106%, respectively. Using this method, an analysis of 34 commercially available cereals detected the presence of deoxynivalenol, 15-acetyl deoxynivalenol, fumonisin B1, fumonisin B2, fumonisin B3, fumonisn A1, fumonisin A2, fumonisin A3, and zearalenone in corn samples with high concentration and frequency. Trichothecenes was detected from wheat samples with high frequency; in particular, the concentration of deoxynivalenol was high. Conversely, α-zearalenol, β-zearalenol, α-zearalanol, and β-zearalanol were not detected in any of the samples.

Monohydroxylated polycyclic aromatic hydrocarbons influence spicule formation in the early development of sea urchins (Hemicentrotus pulcherrimus)

We previously demonstrated that monohydroxylated polycyclic aromatic hydrocarbons (OHPAHs), which are metabolites of polycyclic aromatic hydrocarbons (PAHs), act on calcified tissue and suppress osteoblastic and osteoclastic activity in the scales of teleost fish. The compounds may possibly influence other calcified tissues. Thus, the present study noted the calcified spicules in sea urchins and examined the effect of both PAHs and OHPAHs on spicule formation during the embryogenesis of sea urchins. After fertilization, benz[a]anthracene (BaA) and 4-hydroxybenz[a]anthracene (4-OHBaA) were added to seawater at concentrations of 10(-8) and 10(-7) M and kept at 18 °C. The influence of the compound was given at the time of the pluteus larva. At this stage, the length of the spicule was significantly suppressed by 4-OHBaA (10(-8) and 10(-7) M). BaA (10(-7) M) decreased the length of the spicule significantly, while the length did not change with BaA (10(-8) M). The expression of mRNAs (spicule matrix protein and transcription factors) in the 4-OHBaA (10(-7) M)-treated embryos was more strongly inhibited than were those in the BaA (10(-7) M)-treated embryos. This is the first study to demonstrate that OHPAHs suppress spicule formation in sea urchins.

Identification and quantification of fumonisin A1, A2, and A3 in corn by high-resolution liquid chromatography-orbitrap mass spectrometry

Three compounds, hypothesized as fumonisin A1 (FA1), fumonisin A2 (FA2), and fumonisin A3 (FA3), were detected in a corn sample contaminated with mycotoxins by high-resolution liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap MS). One of them has been identified as FA1 synthesized by the acetylation of fumonisin B1 (FB1), and established a method for its quantification. Herein, we identified the two remaining compounds as FA2 and FA3, which were acetylated fumonisin B2 (FB2) and fumonisin B3 (FB3), respectively. Moreover, we examined a method for the simultaneous analysis of FA1, FA2, FA3, FB1, FB2, and FB3. The corn samples were prepared by extraction using a QuEChERS kit and purification using a multifunctional cartridge. The linearity, recovery, repeatability, limit of detection, and limit of quantification of the method were >0.99, 82.9%-104.6%, 3.7%-9.5%, 0.02-0.60 μg/kg, and 0.05-1.98 μg/kg, respectively. The simultaneous analysis of the six fumonisins revealed that FA1, FA2, and FA3 were present in all corn samples contaminated with FB1, FB2, and FB3. The results suggested that corn marketed for consumption can be considered as being contaminated with both the fumonisin B-series and with fumonisin A-series. This report presents the first identification and quantification of FA1, FA2, and FA3 in corn samples.

Atmospheric chlorinated polycyclic aromatic hydrocarbons in East Asia

This study estimates atmospheric concentrations of chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and polycyclic aromatic hydrocarbons (PAHs) in East Asia using a Gas Chromatograph with High Resolution Mass Spectrometer (GC-HRMS). ClPAHs are ubiquitously generated from PAHs through substitution, and some ClPAHs show higher aryl hydrocarbon receptor (AhR)-mediated activities than their parent PAHs. Atmospheric particles were collected using a high-volume air sampler equipped with a quartz-fiber filter. We determined the ClPAH concentrations of atmospheric particles collected in Japan (Sapporo, Sagamihara, Kanazawa, and Kitakyushu), Korea (Busan), and China (Beijing). The concentrations of ClPAHs were highest in the winter Beijing sample, where the total mean concentration was approximately 15-70 times higher than in the winter samples from Japan and Korea. The concentrations of Σ19ClPAHs and Σ9PAHs were significantly correlated in the Kanazawa and the Busan samples. This indicates that within those cities ClPAHs and PAHs share the same origin, implying direct chlorination of parent PAHs. Toxic equivalent concentrations (TEQs) of the total ClPAHs and PAHs were lowest in Kanazawa in the summer, reaching 1.18 and 2610fg-TEQm(-3) respectively, and highest in Beijing in the winter, reaching 627 and 4240000fg-TEQm(-3) respectively.