[Benchmark dose estimation of polycyclic aromatic hydrocarbons exposure base on Bayesian kernel machine regression].

Objective: To explore benchmark dose (BMD) estimations of polycyclic aromatic hydrocarbons (PAHs) based on Bayesian kernel machine regression (BKMR) . Methods: A total of 155 adult residents of a coking plant in Shanxi Province who were surveyed in summer (June to August) from 2014 to 2019 were selected as the research objects. Fasting elbow vein blood of the subjects was collected in the morning for automatic analysis and detection of blood routine. Morning urine samples were collected for automatic analysis and detection of urine routine and urine creatinine detection. BKMR model combined with BMD method was used to calculate the acceptable doses of PAHs exposure on red blood cell damage in non-occupational population. Results: The concentration of hydroxylpolycyclic aromatic hydrocarbons (OH-PAHs) in the red blood cells abnormal group (n=117) was significantly higher than that in the normal group (n=38) (P<0.01). In the combined effect of OH-PAHs, 2-hydrol-naphthalene contributed the most, and the posterior inclusion probability (PIP) value was 0.9354. When OH-PAHs ≥P(55) concentration, the joint effect on the risk of red blood cell abnormalities increased as the concentration of the OH-PAHs mixture increased. When OH-PAHs were at P(65) and P(75) concentrations, respectively, the risk of red blood cell abnormalities in adults were 3.09 and 4.98 times that of OH-PAHs at P(50) concentrations, respectively. Compared with high concentration, low concentration of OH-PAHs exposure was more sensitive to red blood cell darmage. The acceptable doses of 8 kinds of OH-PAHs were 1.010 µmol/mol Cr (2-hydrol-naphthalene), 0.743 µmol/mol Cr (1-hydrol-naphthalene), 0.901 µmol/mol Cr (2-hydroxy-fluorene) and 0.775 µmol/mol Cr (1-hydroxy-phenanthrene), 0.737 µmol/mol Cr (1-hydroxy-pyrene), 0.607 µmol/mol Cr (9-hydroxy-fluorene), 0.713 µmol/mol Cr (2-hydroxy-phenanthrene) and 0.628 µmol/mol Cr (3-hydroxybenzo[a] pyrene), respectively. Conclusion: OH-PAHs mixture has positive combined effect on red blood cell damage in non-occupational population, and low concentration of OH-PAHs exposure is more sensitive to red blood cell damage. It is recommended that the exposure dose of PAHs should be controlled within 1 µmol/mol Cr.

Impacts of shipyard oil leakage on the PAHs and PCBs occurrence in Xiangshan Bay, China.

Here, we studied the shipyard impacts on the distribution of PAHs and PCBs in the semi-enclosed Xiangshan Bay, an important mariculture zone in China. The results showed that the shipyard caused a pollution plume for PAHs but not for PCBs. As characteristic pollutants of oil leakage, the PAHs had concentrations of up to 55.82 ng L-1 in the water, 2235.04 ng g-1 in suspended particulate matter (SPM), and 1489.60 ng g-1 in sediment. The PAHs in water and SPM were dominated by phenanthrene and pyrene that were mostly derived from lubricant and diesel, while those in sediments were dominated by the high-molecular-weight PAHs, such as indeno[1,2,3-c,d]pyrene. In contrast, the PCBs concentrations reached up to 10.17 ng L-1, 79.72 ng g-1, and 124.33 ng g-1 in the seawater, SPM, and sediment samples, respectively, and they did not show spatial patterns affected by the shipyard. Moreover, the health risk assessment indicated that the shipyard discharge caused a substantial PAHs ecological risk to the adjacent and downstream water environment. Therefore, point source discharge in semi-enclosed bays should be paid close attention to due to the strong pollutant transport effect.

Anaerobic biodegradation of pyrene and benzo[a]pyrene by a new sulfate-reducing Desulforamulus aquiferis strain DSA.

The study of anaerobic high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) biodegradation under sulfate-reducing conditions by microorganisms, including microbial species responsible for biodegradation and relative metabolic processes, remains in its infancy. Here, we found that a new sulfate-reducer, designated as Desulforamulus aquiferis strain DSA, could biodegrade pyrene and benzo[a]pyrene (two kinds of HMW-PAHs) coupled with the reduction of sulfate to sulfide. Interestingly, strain DSA could simultaneously biodegrade pyrene and benzo[a]pyrene when they co-existed in culture. Additionally, the metabolic processes for anaerobic pyrene and benzo[a]pyrene biodegradation by strain DSA were newly proposed in this study based on the detection of intermediates, quantum chemical calculations and analyses of the genome and RTqPCR. The initial activation step for anaerobic pyrene and benzo[a]pyrene biodegradation by strain DSA was identified as the formation of pyrene-2-carboxylic acid and benzo[a]pyrene-11-carboxylic acid by carboxylation Thereafter, CoA ligase, ring reduction through hydrogenation, and ring cracking occurred, and short-chain fatty acids and carbon dioxide were identified as the final products. Additionally, DSA could also utilize benzene, naphthalene, anthracene, phenanthrene, and benz[a]anthracene as carbon sources. Our study can provide new guidance for the anaerobic HMW-PAHs biodegradation under sulfate-reducing conditions.

Disturbance of OH-PAH metabolites in urine induced by single PAH lab exposure.

Due to the high exposure toxicity and individual variability of polycyclic aromatic hydrocarbons (PAHs), it is difficult to accurately characterize the actual exposure of exposed individuals through external exposure detection. In this study, the monohydroxyl metabolites of naphthalene, phenanthrene, pyrene, and 9-fluorenone were identified in the urine of low-dose PAH-exposed individuals based on ultra-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS), and their concentrations were monitored for 15 consecutive days after exposure. The results showed that the metabolite concentrations of naphthalene, phenanthrene, and pyrene were basically the same, and all of them reached the maximum value at day 8. In contrast, the metabolite of 9-fluorenone reached its maximum value on day 2. This study showed that the four metabolites were strongly correlated with their parent PAH exposure, with a wide detection window, and their assays were specific, sensitive, and reliable, while the sampling difficulty was low, so the four hydroxylated PAHs may be potential low-dose biomarkers of PAH internal exposure. This study will provide methodological and data support for further health risk studies involving internal exposure to organic pollutants such as PAHs.

Monitoring microplastic-contaminant sorption processes in real-time using membrane introduction mass spectrometry.

Microplastics are environmentally ubiquitous and their role in the fate and distribution of trace contaminants is of emerging concern. We report the first use of membrane introduction mass spectrometry to directly monitor the rate and extent of microplastic-contaminant sorption. Target contaminant (naphthalene, anthracene, pyrene, and nonylphenol) sorption behaviours were examined at nanomolar concentrations with four plastic types: low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), and polystyrene (PS). Under the conditions employed here, short-term sorption kinetics were assessed using on-line mass spectrometry for up to one hour. Subsequent sorption was followed by periodically measuring contaminant concentrations for up to three weeks. Short-term sorption followed first order kinetics with rate constants that scaled with hydrophobicity for the homologous series of polycyclic aromatic hydrocarbons (PAHs). Sorption rate constants on LDPE for equimolar solutions of naphthalene, anthracene, and pyrene were 0.5, 2.0, and 2.2 h-1, respectively, while nonylphenol did not sorb to pristine plastics over this time period. Similar trends among contaminants were observed for other pristine plastics with 4- to 10-fold faster sorption rates associated with LDPE when compared to PS and PP. Sorption was largely complete after three weeks, with the percent analyte sorbed ranging from 40-100% across various microplastic-contaminant combinations. Photo-oxidative ageing of LDPE had little effect on PAH sorption. However, a marked increase in nonylphenol sorption was consistent with increased hydrogen-bonding interactions. This work provides kinetic insights into surface interactions and describes a powerful experimental platform to directly observe contaminant sorption behaviours in complex samples under a variety of environmentally relevant conditions.

Investigation of the spatial distribution of airborne polycyclic aromatic hydrocarbons using Rhytidiadelphus squarrosus in Tórshavn, Faroe Islands.

Due to adverse effects of Polycyclic Aromatic Hydrocarbons (PAHs) on human health, it is important to understand how airborne PAHs, are spatially distributed within urban areas. Moss has been shown to be a suitable material for biomonitoring of airborne PAH pollution. In this study, the moss Rhytidiadelphus squarrosus was sampled throughout Tórshavn, Faroe Islands. 53 Rhytidiadelphus squarrosus samples were extracted using a matrix solid-phase dispersive extraction method and analysed for 19 parent PAHs and six groups of alkylated PAHs using gas chromatography mass-spectrometry. All PAHs were quantified in at least one Rhytidiadelphus squarrosus sample, and the sum of the EPA 16 PAHs (Æ©PAHEPA16) ranged from 0.90 to 344 µg kg-1 dry weight. Higher concentrations were found close to the harbour and the main roads. The spatial correlation was investigated for the Æ©PAHEPA16, pyrene, fluoranthene, chrysene, benzo(e)pyrene, benzo(g,h,i)perylene, C1-phenanthrenes/C1-anthracenes, and C2-phenanthrenes/C2-anthracenes using variograms. The effective range of the spatial correlation was between 500 to 700 m of all PAHs. The evaluation of diagnostic ratios of fluoranthene to pyrene, and benzo(a)anthracene to chrysene suggest that different pollution sources affect urban areas of different types. To the best of our knowledge, this is the first time airborne PAH pollution patterns were mapped in an Arctic town, and the first time, Rhytidiadelphus squarrosus was used for tracing PAH pollution sources. Rhytidiadelphus squarrosus is suitable for biomonitoring and mapping PAH pollution within urban areas since it is widespread, and suitable for mapping PAHs.

Characterization of chemical components of fresh and aged aerosol from vehicle exhaust emissions in Hong Kong.

The chemical properties of fresh and aged aerosol emitted during controlled vehicular exhaust emissions were characterized in the analysis. Pyrene (10417.1 ± 534.9 ng kg-1) is the most abundant of all analyzed compounds in total fresh emission and succinic acid (57359.8 ± 4000.3 ng kg-1) is for the total aged emission. The fresh emission factors (EFfresh) of all compounds in the n-alkanes group demonstrate higher average emissions for the two vehicles with EURO 3 standard compared to the other vehicles. The EFfresh for benzo [a]pyrene is in descending order: G1 (183.1 ± 144.7 ng kg-1) > G3 (103.4 ± 60.1 ng kg-1) > G4 (91.2 ± 80.1 ng kg-1) > G2 (88.6 ± 93.9 ng kg-1). Aged/fresh (A/F) emission ratios (>20) confirmed that these diacid compounds are generated by the photooxidation of primary pollutants that emitted from gasoline combustions. High A/F ratios (>200) in phthalic acid, isophthalic acid and terephthalic acid under idling mode imply relatively more intense photochemical reactions for their productions compared with other chemical groups. Strong positive correlations (r > 0.6) were observed between the degradation of toluene and formations of pinonic acid, succinic acid, adipic acid, terephthalic acid, glutaric acid and citramalic acid after the aging process, suggesting possible photooxidation of toluene that can lead to secondary organic aerosol (SOA) formation in the urban atmosphere. The findings demonstrate that vehicle emission standards for pollution in relation to the change of particulate matter chemical compositions and SOA formations. The results warrant a need for regulated reformulation for such vehicles.

Focusing on testosterone levels in male: A half-longitudinal study of polycyclic aromatic hydrocarbon exposure and diastolic blood pressure in coke oven workers.

Polycyclic aromatic hydrocarbons (PAHs) can interfere with testosterone levels, and low levels of testosterone are associated with increased cardiovascular events. To explore the role of testosterone in PAHs exposure and cardiovascular health, we used data from the 2011-2016 National Health and Nutrition Examination Survey (NHANES) and a longitudinal database of 332 male coke oven workers from China. The urine PAHs, tobacco metabolites and plasma testosterone levels of coke oven workers were measured. There were inverse associations between serum (plasma) testosterone concentrations and the risk of dysarteriotony and dyslipidemia among the NHANES participants and coke oven workers. The results of the cross-lagged panel analysis among workers showed that the decrease in testosterone preceded the increase in diastolic blood pressure (DBP), and the absolute value of the path coefficient from baseline testosterone to follow-up DBP (ß2 = -8.162, P = 0.077) was significantly larger than the absolute value of the path coefficient from baseline DBP to follow-up testosterone (ß1 = -0.001, P = 0.781). Results from the half-longitudinal mediation analysis showed that baseline hydroxyfluorene predicted significant decreases in plasma testosterone from baseline to follow-up (path a: 0.71, 95% CI: 1.26, -0.16), whereas plasma testosterone at baseline also predicted significant increments in DBP from baseline to follow-up (path b: 9.22, 95% CI: 17.24, -1.19). The indirect effect of PAHs on DBP via plasma testosterone level was marginally significant (test for indirect effects a*b (P = 0.08)). In conclusion, testosterone level is a longitudinal precursor to increased DBP and plays an essential role in the association between PAHs exposure and damage to the cardiovascular system. Coke oven workers with low plasma testosterone levels are more likely to experience adverse changes in blood pressure and lipid levels after exposure to PAHs.

Adsorption of 2-hydroxynaphthalene, naphthalene, phenanthrene, and pyrene by polyvinyl chloride microplastics in water and their bioaccessibility under in vitro human gastrointestinal system.

The interaction of microplastics (MPs) and organic pollutants has recently become a focus of investigation. To understand how microplastic residues affect the migration of organic pollutants, it is necessary to examine the adsorption and desorption behavior of organic pollutants on MPs. In this study, integrated adsorption/desorption experiments and theoretical calculations were used to clarify the adsorption mechanism of 2-hydroxynaphthalene (2-OHN), naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) by polyvinyl chloride microplastics (PVC-MPs). Based on the phenomenological mathematical models, the rate-limiting step for analyte adsorption onto PVC-MPs was adsorption onto active sites (R2 = 0.865-0.995). Except for PHE, analyte adsorption isotherms were well described by the Freundlich model (R2 = 0.992-0.998), and adsorption thermodynamics showed that analyte adsorption on PVC-MPs was a spontaneous exothermic process (ΔH0 < 0; ΔG0 < 0). Based on the order of adsorption efficiency of 2-OHN < NAP < PHE < PYR, which is identical to the competitive adsorption experiment, polycyclic aromatic hydrocarbon (PAH) adsorption on PVC-MPs increased as the aromatic ring number increased and the hydroxyl content decreased. The release of 2-OHN (49 %-52 %) from PVC-MPs into the simulated gastrointestinal environment was greater than that of NAP (5.5 %-5.7 %). Theoretical calculations and adsorption tests indicated that hydrophobic interaction was the primary influence on the adsorption of PAHs and their hydroxylated derivatives by PVC-MPs. These findings improve our understanding of MPs' behavior and dangers as pollutant carriers in the aquatic environment and help us develop recommendations for the pollution control of MPs.

Polycyclic Aromatic Hydrocarbons (PAHs) Contamination in Chrysichthys nigrodigitatus Lacépède, 1803 from Lake Togo-Lagoon of Aného, Togo: Possible Human Health Risk Suitable to Their Consumption.

The Lake Togo-Lagoon of Aného is located in the coastal zone where phosphorite mining is carried out. This mining discharges all kinds of waste such as fuel oil into the surrounding environment without prior treatment. Moreover, the hydrosystem receives runoff and river inputs after having crossed and leached from mining and urban soils. This study aims to determine the polycyclic aromatic hydrocarbons (PAHs) contamination in commercially consumed fish species (Chrysichthys nigrodigitatus) from that hydrosystem and the associated health risks for consumers. For that, fish sample collection was performed during the dry season. Afterwards, their muscles, gills, and livers were cut and 12 PAHs were analyzed using gas chromatography coupled with a mass spectrometer (GC-MS). The total PAHs (tPAHs) concentrations in fish tissues ranged from 5.24 to 48.40 µg/kg with average concentration of 14.51 ± 8.95 µg/kg in muscles, from 5.90 to 28.20 µg/kg averaging 14.90 ± 5.19 µg/kg in gills, and from 43.20 to 149.00 µg/kg with an average of 80.74 ± 27.08 µg/kg in livers. The average concentrations of low molecular weight PAHs (LMW PAHs) were 10.82 ± 9.61 µg/kg in muscles, 8.25 ± 5.43 µg/kg in gills, and 47.97 ± 22.56 µg/kg in livers whereas those of high molecular weight of PAHs (HMW PAHs) were 4.10 ± 2.14 µg/kg in muscles, 7.98 ± 3.96 µg/kg in gills, and 32.77 ± 8.66 µg/kg in livers. An overall trend of decreasing concentrations with increasing fish size classes was observed for some PAHs (Naphtalene, Pyrene in muscles, for Pyrene, Benzo(a)Anthracene, Chrysene in gills and for Naphtalene, Phenanthrene in livers). The PAHs in these fish might have pyrogenic and petrogenic sources, with the dominance of pyrogenic, and all of the total hazard quotients (THQ) are less than 1. This situation must not be neglected for better planning sustainable management of the target ecosystem.

The impact of the 2019/2020 Australian landscape fires on infant feeding and contaminants in breast milk in women with asthma.

BACKGROUND: The 2019/2020 Australian landscape fires (bushfires) resulted in prolonged extreme air pollution; little is known about the effects on breastfeeding women and their infants. This study aimed to examine the impact of prolonged landscape fires on infant feeding methods and assess the concentration of polycyclic aromatic hydrocarbons (PAHs) and elements in breast milk samples. METHODS: From May - December 2020, women with asthma, who were feeding their infants during the fires, were recruited from an existing cohort. Data on infant feeding and maternal concern during the fires were retrospectively collected. Breast milk samples were collected from a sample of women during the fire period and compared with samples collected outside of the fire period for levels of 16 PAHs (gas chromatography coupled with mass spectrometry), and 20 elements (inductively coupled plasma-mass spectrometry). RESULTS: One-hundred-and-two women who were feeding infants completed the survey, and 77 provided 92 breast milk samples. Two women reported concern about the impact of fire events on their infant feeding method, while four reported the events influenced their decision. PAHs were detected in 34% of samples collected during, versus no samples collected outside, the fire period (cross-sectional analysis); specifically, fluoranthene (median concentration 0.015 mg/kg) and pyrene (median concentration 0.008 mg/kg) were detected. Women whose samples contained fluoranthene and pyrene were exposed to higher levels of fire-related fine particulate matter and more fire days, versus women whose samples had no detectable fluoranthene and pyrene. Calcium, potassium, magnesium, sodium, sulphur, and copper were detected in all samples. No samples contained chromium, lead, nickel, barium, or aluminium. No statistically significant difference was observed in the concentration of elements between samples collected during the fire period versus outside the fire period. CONCLUSIONS: Few women had concerns about the impact of fire events on infant feeding. Detection of fluoranthene and pyrene in breast milk samples was more likely during the 2019/2020 Australian fire period; however, levels detected were much lower than levels expected to be related to adverse health outcomes.

Toxicokinetic analyses of naphthalene, fluorene, phenanthrene, and pyrene in humans after single oral administration.

Polycyclic aromatic hydrocarbons (PAHs) are generated by incomplete combustion of organic matter. They have health effects in multiple organs and can cause lung, skin, and bladder cancers in humans. Although data regarding their toxicity is available, information on the absorption, distribution, metabolism, and excretion of PAHs in humans is very limited. In the present study, deuterium-labeled naphthalene (Nap), fluorene (Flu), phenanthrene (Phe), and pyrene (Pyr) were orally administered as a single dose (0.02-0.04 mg/kg) to eight healthy adults. Both serum and urine samples were monitored for 72 h after the exposure. Parent compounds and PAH metabolites (monohydroxy-PAHs; OH-PAHs) were measured by headspace-solid phase microextraction coupled with gas chromatography-mass spectrometry and high-performance liquid chromatography-tandem mass spectrometry, respectively. Based on the time-concentration profiles in serum and urine, non-compartmental analysis was performed, and two-compartment models were constructed and validated for each PAH. Subsequently, all of the parent compounds were rapidly absorbed (Tmax: 0.25 to 1.50 h) after oral administration and excreted in urine with a biological half-life (T1/2) of 1.01 to 2.99 h. The fractional urinary excretion (Fue) of OH-PAHs ranged from 0.07 % to 11.3 %; their T1/2 values ranged from 3.4 to 11.0 h. The two-compartment models successfully described the toxicokinetic characteristics of each PAH and its metabolites. Fue and the two-compartment models could be useful tools for exposure simulation or dose-reconstruction of PAHs. The results of this study will provide useful information for interpreting biomonitoring data of PAHs.

Effects of H19/SAHH/DNMT1 on the oxidative DNA damage related to benzo[a]pyrene exposure.

The mechanisms that long noncoding RNA (lncRNA) H19 binding to S-adenosylhomocysteine hydrolase (SAHH) interacted with DNA methyltransferase 1 (DNMT1) and then regulated DNA damage caused by polycyclic aromatic hydrocarbons (PAHs) remain unclear. A total of 146 occupational workers in a Chinese coke-oven plant in 2014 were included in the final analyses. We used high-performance liquid chromatography mass spectrometry (HPLC-MS) equipped to detect urine biomarkers of PAHs exposure, including 2-hydroxynaphthalene (2-NAP), 2-hydroxyfluorene (2-FLU), 9-hydroxyphenanthrene (9-PHE) and 1-hydroxypyrene (1-OHP). The levels of SAM and SAH in plasma were detected by HPLC-ultraviolet. By constructing various BEAS-2B cell models exposed to 16 µM benzo[a]pyrene (BaP) for 24 h, toxicological parameters reflecting distinct mechanisms were evaluated. We documented that urinary 1-hydroxypyrene (1-OHP) levels were positively associated with blood H19 RNA expression (OR: 1.51, 95% CI: 1.03-2.19), but opposite to plasma SAHH activity (OR: 0.63, 95% CI: 0.41-0.98) in coke oven workers. Moreover, by constructing various BEAS-2B cell models exposed to benzo[a]pyrene (BaP), we investigated that H19 binding to SAHH exaggerated DNMT1 expressions and activity. Suppression of H19 enhanced the interaction of SAHH and DNMT1 in BaP-treated cells, decreased eight-oxoguanine DNA glycosylase 1 (OGG1) methylation, reduced oxidative DNA damage and lessened S phase arrest. However, SAHH or DNMT1 single knockdown and SAHH/DNMT1 double knockdown showed the opposite trend. A H19/SAHH/DNMT1 axis was involved in OGG1 methylation, oxidative DNA damage and cell cycle arrest by carcinogen BaP.

Insights into the accumulation, distribution and toxicity of pyrene associated with microplastics in rice (Oryza sativa L.) seedlings.

Microplastic and polycyclic aromatic hydrocarbons (PAHs) can be introduced into agroecosystems through various agricultural activities and may threaten food safety and human health. However, little research has focused on the behavior of microplastics-associated PAHs and their toxicity effects in agroecosystems, especially in crops. In the present study, we investigated the accumulation, distribution and toxicity of pyrene associated with polyethylene (PE) microplastics in rice (Oryza sativa L.). With quantitative analysis using 14C isotope labelling, the total accumulation efficiency of 14C-pyrene in rice seedlings was 22.4 ± 1.2% and 14.5 ± 0.3% when exposed to freely dissolved pyrene and PE-associated pyrene, respectively. The translocation of 14C-pyrene was significantly decreased by microplastics adsorption even when the amount of pyrene in the rice roots had no significant difference. Subcellular distribution of 14C-pyrene in rice suggested that PE microplastics-associated pyrene located more on cell walls than free dissolved pyrene. Furthermore, results showed free pyrene, but not PE-associated pyrene, significantly decreased the length and biomass of rice roots as well as increased the activities of antioxidant enzymes (superoxide dismutase and catalase). It indicated that the association with microplastics alleviated the phytotoxicity of pyrene in rice seedlings. These findings shed new light on the environmental behavior and effects of PAHs associated with microplastics in crops and will be helpful to its comprehensive risks assessment.

Evaluation and characterization of biochar on the biogeochemical behavior of polycyclic aromatic hydrocarbons in mangrove wetlands.

As the inter-tidal regions between land and ocean, mangrove ecosystems have high polycyclic aromatic hydrocarbons (PAHs) content, and the over accumulation of PAHs in mangrove wetland poses a serious ecological risk to the health of plant and living creatures. Comparison to the agricultural sources -biochar, biochar produced from wetland plant has lower O/C (molar ratio), larger N contents, higher stability and more benefits. However, whether the rhizosphere action occurs in biochar- amended sediment and how to influence the biogeochemical behavior of PAH have rarely been reported. In this context, a leaching procedure and pot experiment (60-d) were performed on migration and transformation of PAH at the sediment, and toxicity and their bioavailability in plant affected by the presence of Kandelia obovate-derived biochar in Southeast China. Root exudates amendments significantly increased the cumulative leaching-loss of pyrene by 36-51 % with or without biochar amendment via continuous diffusion and partition process, and biochar amendments decreased the bioavailability of pyrene (16.8-25.8 %) probably due to a faster pyrene sorption on inter-phase transport against desorption. The regression analysis indicated a significant relationship (p < 0.05) between leachate pH and pyrene concentrations. Notably, the bioaccumulation of pyrene on K. obovate parts had significant negative correlation (p < 0.05) to biochar. The activities of four key antioxidizes (phenylalanine ammonia-lyase, dismutases, peroxidases and catalases) were significantly decreased with the application of biochar. Moreover, biochar plays a positive role in cytochrome C release and phosphatidylserine secretion, and a combined biochar-rhizosphere approach can improve the stress tolerance and resistance of K. obovate with an enhanced synergetic effect, which could be a feasible remediation strategy for alleviating the mangrove sediment contaminated by PAH.

Diminishing toxicity of pyrene on photosynthetic performance of soybean using Bacillus subtilis (NCIM 5594).

Polycyclic aromatic hydrocarbons are persistent organic pollutants causing serious environmental problems, being toxic to plants and difficult to remediate. Pyrene is one such extremely dangerous compound that is toxic for the environment. This study suggests the use of Bacillus subtilis (National Collection of Industrial Microorganisms [NCIM] 5594) to overcome inhibitory effects of pyrene on soybean photosynthesis. The toxicity of pyrene to soybean was evident from a significant decrease in seed germination parameters, photosynthetic performance and biomass during growth of soybean in pyrene contaminated soil. Efficiency of performance index, light absorption, trapping and electron transport were reduced in plants grown in pyrene contaminated soil while significant recovery in these parameters was observed in plants grown in pyrene+B. subtilis treated soil. Activity levels of dehydrogenase and lipase enzymes significantly recovered in pyrene+B. subtilis treated soil. After extraction of pyrene from soil and soybean plant, concentration of pyrene was lowered in pyrene+B. subtilis treated soil and plants. These findings suggest efficient degradation of pyrene by B. subtilis . About 70% degradation of pyrene was achieved in soil using B. subtilis ; thus it is a useful strain for crop improvement in pyrene polluted soil.

Cytogenetic analysis of coke oven workers in Eastern Slovakia.

OBJECTIVE: Our study aimed to evaluate the extent of polycyclic aromatic hydrocarbon (PAH) exposure in coke oven workers from Eastern Slovakia by cytogenetic analysis of human peripheral lymphocytes. METHODS: A total of 81 peripheral blood samples were collected from PAH-exposed workers (mean age 45.84 ± 9.73 years) and 30 samples constituted the control group (41.93 ± 15.39 years). The samples were processed using routine cytological analysis. Conventional cytogenetic analysis of human peripheral lymphocytes has been used to evaluate the effects of PAHs. RESULTS: Comparison of the aberrant cells in the total exposed with the controls showed a significant difference (p < 0.05). A high level of significance (p < 0.001) was observed when comparing the gaps between the exposed group and the control group. There was a significant difference (p < 0.01) in aberrant cells and chromatid breaks (p < 0.05) in the GR1 working subgroup compared with the control group. The results of the correlation analysis did not show a significant relationship between the length of occupational exposure and the frequency of aberrant cells (r = 0.071, p = 0.529). Similarly, no association was observed between smoking among coke plant workers and the frequency of aberrant cells (r = 0.117, p = 0.538). CONCLUSION: Cytogenetic analysis showed an increased frequency of chromosomal aberrations in coke oven workers in Eastern Slovakia.

[Association among urinary polycyclic aromatic hydrocarbons metabolites, SAHH activity and H19 expression in coke oven workers].

Objective: To investigate the relationship of polycyclic aromatic hydrocarbons (PAHs) exposure, S-adenosylhomocysteine hydrolase (SAHH) activity and long noncoding RNA H19 gene expression in the urine of coke oven workers. Methods: In September 2019, in a coking plant in Taiyuan City, 146 male workers who had worked in coke oven operations for one year were selected through a completely random sampling method, and their basic personal information was collected by questionnaire survey, and blood and urine samples were collected. The levels of 4 PAHs metabolites 2-hydroxfluorene (2-FLU), 2- hydroxynaphthalene (2-NAP), 9-hydroxyphenanthren (9-PHE), and 1-hydroxypyrene (1-OHP) in urine were detected by high performance liquid chromatography (HPLC) -fluorescence detection method. HPLC-UV detection method was used to detect the content of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in plasma, and the SAHH activity value was obtained by calculating the ratio. Reverse transcription PCR method was used to determine the H19 gene expression level. Urine levels of 2-FLU, 2-NAP, 9-PHE, and 1-OHP were divided into Q(1), Q(2), Q(3), and Q(4) groups according to quartiles (P(25), P(50), P(75)). Regression, trend test and restricted cubic splines were used to analyze the relationship among PAHs metabolites, SAHH activity, H19 gene expression and their dose-response. Results: The median age of coke oven workers was 39.60 years old, the median length of service was 20.38 years, and the urinary levels of 2-FLU, 2-NAP, 9- PHE, and 1-OHP were 0.29, 0.74, 0.09, and 0.06 µg/mmol Cr, respectively. The levels of 2-FLU, 2-NAP and 9-PHE in the urine of workers were significantly different between groups with different 1-OHP levels (P<0.05). After adjusting for age, length of service, smoking, drinking, and levels of 2-FLU, 2-NAP and 9-PHE, SAHH activity decreased with the increase of urinary 1-OHP level (OR=0.63, 95%CI: 0.41-0.98, P=0.038), showing a nonlinear relationship (P(nonlinear)= 0.030). H19 gene expression increased with the increase of urinary 1- OHP level (OR=1.51, 95%CI: 1.03-2.19, P=0.033), there was a linear relationship (P(trend)= 0.058). The relationship between the other three metabolites in urine and SAHH activity and H19 gene expression was not statistically significant (P>0.05) . Conclusion: Urinary 1-OHP level may be a risk factor for decreased SAHH activity and increased H19 gene expression in coke oven workers.

The extraction of polycyclic aromatic hydrocarbons from water samples with aromatic-dithiocarbamate modified magnetic nanoparticles.

Considering the urgent need for the analysis of trace-level pollutants in water samples, the pre-concentration of micropollutants in water samples has been the focus of extensive research. Among current pretreatment methods, the solid phase extraction (SPE) technique has received enormous attention because of its low cost, ease of operation and high efficiency. In this work, a new adsorbent (Fe3O4@Au@DTC NPs) was acquired through modification of Fe3O4 nanoparticles (NPs) with gold (Au) and dithiocarbamate (DTC). To investigate their application ability, the adsorbent were utilized as an SPE adsorbent to enrich polycyclic aromatic hydrocarbons in water (PAHs, fluoranthene, pyrene, benzo anthracene, benzo fluoranthene, benzo pyrene). The obtained Fe3O4@Au@DTC NPs were confirmed by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and UV-Vis spectrum. Under optimal conditions, the calibration curves were obtained in the range of 10-500 ng L-1, while the limit of detection (LOD) ranged in 1.17-2.31 ng L-1. Furthermore, 50 mg of Fe3O4@Au@DTC NPs could extract trace PAHs from 500 mL real water samples into 1 mL eluent, and the spiked recoveries of five PAHs in river water and tap water reached 72-106% with relative standard deviations varying between 3.3-5.18%. Through the conversion of amines into DTC, we acquire desiring group modified Fe3O4 NPs, which showed great prospects in magnetic solid-phase extraction sphere and environmental field.

[Study on the relationship between the pathological type of lung cancer caused by coke oven discharge and the contact type and exposure time].

Objective: To study the pathological types of lung cancer caused by coke oven emissions and analyze the correlation between different exposure levels. Methods: In October 2020, the relevant data of 86 confirmed cases of lung cancer caused by coke oven emissions (including basic information of patients, relevant occupational exposure and clinical data) were collected, The workers were grouped according to the different COEs concentrations in their posts: workers in auxiliary posts were taken as the low exposure group (11 persons) , The workers at coke side and furnace bottom are the medium exposure group (14 persons) , and the workers at furnace top are the high exposure group (61 persons) , and the correlation between pathological types of lung cancer and different exposure levels was analyzed. Results: There was no significant difference in age and length of service among the groups (P>0.05) ; The number of lung cancer cases and pathological types among workers in each group were statistically significant (P=0.044) . After adjusting for interference factors, the number of undifferentiated cancers (mainly small cell lung cancer) increased with the increase of exposure level, with a statistically significant difference (P=0.001) . The incidence of lung cancer increased gradually with the length of service, and the incidence rate of lung cancer among workers of different working ages was statistically significant (P<0.05) . Conclusion: Undifferentiated small cell carcinoma is the most common pathological type of lung cancer caused by coke oven emissions, and the incidence of lung cancer tends to increase with the length of service.