scholarly journals Degradation of Polycyclic Aromatic Hydrocarbons by Consortium 5H Under Hypersaline Conditions

Author(s):  
Jiaqi Jin ◽  
Zuotao Zhang ◽  
Lu Han ◽  
Chicheng Yan ◽  
Xinxing Ding ◽  
...  

Abstract PAHs were widely detected accumulated in saline and hypersaline environments. The halotolerant and halophilic microbes were considered as the most suitable player for the elimination of PAHs in such environments. In this study, consortium 5H was enriched under 5% salinity that was able to completely degrade phenanthrene in 5 days. By high-throughput sequencing, consortium 5H was identified mainly composed of Methylophaga, Marinobacter and Thalassospira. Combined with the investigation of intermediates and enzymatic activities, the degradation pathway of consortium 5H on phenanthrene was proposed. Meanwhile, consortium 5H was identified with ability to tolerate a wide range of salinity (1% to 10%) and initial PAHs concentration (50 mg/L to 400 mg/L). It was also able to work under neutral to week alkaline conditions (pH from 6 to 9) and the phytotoxicity of the produced intermediates showed no significant difference with distilled water. This study expanded the knowledge of PAH-degradation under hypersaline environments and consortium 5H was proposed with a good potential for the elimination of PAHs pollution under saline/hypersaline environments.

2020 ◽  
Author(s):  
Pengcheng Chen ◽  
Shadi Fatayer ◽  
Bruno Schuler ◽  
Jordan N. Metz ◽  
Leo Gross ◽  
...  

The initial thermal reactions of aromatic hydrocarbons are relevant to many industrial applications. However, tracking the growing number of heavy polycyclic aromatic hydrocarbon (PAH) products is extremely challenging because many reactions are unfolding in parallel from a mixture of molecules. Herein, we studied the reactions of 2,7-dimethylpyrene (DMPY) to decipher the roles of methyl substituents during mild thermal treatment. We found that the presence of methyl substituents is key for reducing the thermal severity required to initiate chemical reactions in natural molecular mixtures. A complex mixture of thermal products including monomers, dimers, and trimers were characterized by NMR, mass spectrometry and non-contact atomic force microscopy (nc-AFM). A wide range of structural transformations including methyl transfer and polymerization reactions were identified. A detailed mechanistic understanding was obtained on the roles of H radicals during the polymerization of polycyclic aromatic hydrocarbons.


2020 ◽  
Vol 64 (4) ◽  
pp. 445-454
Author(s):  
Dong-Hee Koh ◽  
Ju-Hyun Park ◽  
Sang-Gil Lee ◽  
Hwan-Cheol Kim ◽  
Sangjun Choi ◽  
...  

Abstract Objectives Polycyclic aromatic hydrocarbons (PAHs) are well-known carcinogens causing lung and skin cancers in exposed workers. Certain occupations, such as coke production, have been associated with high PAH exposure; however, the number of occupations tested to date remains small. Here, we sought to compare PAH exposure across a wide range of occupations based on levels of 1-hydroxypyrene (1-OHP), the urinary exposure surrogate of PAHs. Methods We collected urine 1-OHP data from the Korean National Environmental Health Survey (KoNEHS), a nationwide biomonitoring survey. We developed a linear regression model, controlling for sex, age, smoking, and survey cycle, and obtained resulting residuals. Then, we computed the fraction of exceeding the third quartile (Q3) level of residuals for each occupation, which is employed as a relative exposure indicator across occupations. Results A total of 15 125 measurements derived from three cycles of KoNEHS were used for analysis. The overall geometric means (GMs) and geometric standard deviation (GSD) of urine 1-OHP levels were 0.16 µg g−1 creatinine and 3.07, respectively. Among the sub-major occupational groups, ‘construction and mining related elementary occupations’ showed the highest fraction (0.45) of exceeding the Q3 level of residuals. Among the minor occupational groups, ‘deliverers’ showed a high fraction (0.42) of exceeding the Q3 level of residuals, which indicates rapidly growing occupations to be addressed. Conclusions Our results provide ancillary information regarding PAH exposure across occupations, especially for occupations for which PAH exposure has not been well characterized.


2006 ◽  
Vol 69 (5) ◽  
pp. 1134-1138 ◽  
Author(s):  
PIERINA VISCIANO ◽  
MONIA PERUGINI ◽  
MICHELE AMORENA ◽  
ADRIANA IANIERI

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in smoked fish as a consequence of cold smoking was studied. Raw fillets of Salmo salar from Norway or the Irish Sea were sampled in a modern smokehouse and examined for PAH content. The same fillets, labeled with an identification number, were sampled immediately after the smoking process and analyzed. Among the investigated compounds, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, and benzo[ghi]perylene were detected in both raw and smoked fillets. No significant difference (P < 0.01) was observed between raw and smoked samples in the concentrations of six PAHs, but significant differences were found for fluorene, anthracene, fluoranthene, benz[a]anthracene, and benzo[ghi]perylene. Results confirm that PAHs concentrations in smoked fish are the product of both sea pollution and the smoking process. A modern smoking plant with an external smoke generator and a mild treatment as described here will not add significantly to the concentration of PAHs, except for some compounds.


2016 ◽  
Vol 70 (9) ◽  
pp. 1520-1528 ◽  
Author(s):  
Ruifang Yang ◽  
Nanjing Zhao ◽  
Xue Xiao ◽  
Shaohui Yu ◽  
Jianguo Liu ◽  
...  

The presence of humic acid (HA) makes it extremely difficult to determine and quantify accurately polycyclic aromatic hydrocarbons (PAHs) in aquatic environment because of their complex and strong interaction. To solve this problem, a new method was developed in this work through the combination of PARAFAC and fluorescence spectroscopy, which mainly includes: (1) the fluorescence quantum yield acquisition of PAHs with and without HA by PARAFAC; (2) the  concentration score correction of PAHs in validation and test sets using the fluorescence quantum yields; and (3) the prediction of PAHs concentration in the validation and test sets in the presence of HA by corrected concentration. Using this method, the PAHs concentration on the level of µg L−1 in the test samples with HA of 2.5 mg/L and 5.0 mg/L can be successfully predicted with the root mean square error below 0.15 µg L−1, relative error of prediction below 4% for validation samples, recoveries of each PAH between 82.5% and 102.6% for test samples.


2018 ◽  
Vol 13 (No. 2) ◽  
pp. 74-82 ◽  
Author(s):  
S. Kuang ◽  
Y. Su ◽  
J. Zhang ◽  
Z. Song ◽  
H. Wang ◽  
...  

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), which are on the United States Environmental Protection Agency (US EPA) priority pollutant list, were studied in ten different soil samples from Shengli Oil Field, China. The total PAHs concentrations in the sampled soils attained 1214.9–2965.1 ng/g (2159.6 ng/g on average). The highest total PAHs concentration was in the soil with a huge content of oil sludge, while the lowest was in fine soil environment areas. The soil contamination with PAHs in the study areas was classified as severe. The major pollutants were naphthalene, phenathrene, fluorine (Flu), pyrene (Pyr), while the detected concentration of benzo(a)pyrene (BaP), benzo(b)fluoranthene was relatively low. Among the 16 kinds of PAHs, the concentration increased in the order: 6 rings < 5 rings < 4 rings < 2 rings < 3 rings. The ratios of Flu/(Flu + Pyr) and indeno benzene(1,2,3-c,d)pyrene (IP)/(IP + BaP) were 0.46–0.48, and 0.36–0.64, respectively. Our results suggest that the main sources of PAHs were petroleum extraction and petroleum combustion. In addition, a small amount of PAHs originated from combustion of grass, woods, and coal.  


The Polycyclic aromatic hydrocarbons (PAHs) and some heavy metals were analysis in the soil samples from urban areas of Kaduna state for their concentration and distribution. Naphthalene, acenaphthylene, acenaphthene, fluorine, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a) pyrene, indeno(1,2,3-cd)perylene, benzo(ghi) perylene and dibenzo(a,h) anthracene were analyzed in three urban soils of Kaduna North, Alegbi and Kaduna South, at 0-15 cm and 16-30 cm depth in wet and dry seasons. After extraction using ultrasonication with hexane and dichloromethane and clean-up, PAHs concentration was measured using gas chromatography. The concentration of all the PAHs obtained ranged between 178.00 mg/g and 787.0 0 mg/g for wet season and 105.10 mg/g and 437.70 mg/g for dry season. The concentrations of PAHs were higher in the subsoil (15-30 cm depth) in the wet season than in the dry season while higher concentrations of all the PAHs were observed in topsoil than subsoil during the dry season. The concentration of PAHs followed the order Kaduna North > Kaduna South > Algabi during the wet season and Kaduna South > Algabi > Kaduna Nort during the dry season. The concentration values of all determined PAHs were below the target value of 1000 mg/g stipulated by Department of Petroleum Resources. The Cd, Cr, Cu and Pb levels in the soil from the study sites were higher than the corresponding control values. The degree of pollution of various metals using the graded standard of Nemero pollution index varied. The concentrations of the metals were found to be above the recommended limits given by USEPA/WHO. This could pose risks and hazards to human and the ecosystem through direct ingestion of contaminated soil


Author(s):  
Christopher Onyemaechi Ezike ◽  
Felix Okaliwe Echor

One hundred and twenty (120) fingerlings of Clarias gariepinus (mean weight: 0.96 ± 0.1g) were randomly exposed to 4 experimental treatments of petroleum, based on LC50 values (6.4mg/L of crude oil, 8.7mg/L of petrol, 8.0mg/L of kerosene and 7.8mg/L of diesel oil) and replicated thrice, to determine polycyclic aromatic hydrocarbons (PAH) in exposed fish for 96 h. There was no significant difference (P > 0.05) in total (PAHs) between crude oil (97.1 ng/uL) and diesel (97.2 ng/uL) exposed fish and also between petrol (53.2 ng/uL) and kerosene (49.6 ng/uL) exposed fish, but there was a significant difference (P < 0.05) in PAH levels of the crude oil/diesel exposed -groups of fish compared to petrol/kerosene exposed -groups of fish (97.1/97.2 and 53.2/49.6 ng/uL). Naphthalene correlated positively to benzo a anthracene (r=0.672, (P < 0.05), benzo b fluoranthene (r=0.681, P < 0.05) and chrysene (r=0.615, P < 0.05) but did not correlate to fluorene. Benzo a anthracene correlated positively to benzo a pyrene (r=0.578, P < 0.05), phenathrene (r=0.685, P < 0.05) but did not correlate to acenaphthene. Fluorene correlated positively to benzo a pyrene (r=0.695, P < 0.05) but did not correlate to chrysene. Chrysene correlated positively to dibenzo a,h, pyrene (r=0.658, P < 0.05) to phenathrene and benzo b fluoranthene (r=0.659, P< 0.05). Indeno 123 cd- pyrene and fluranthene however did not correlate to other PAHs except naphthanene, acenaphthene and acenaphthylene. The level of PAH in fish may translate to the toxicity effect since crude oil and diesel with lower LC50 (6.4 and 7.8 mg/L)   deposited greater PAH than kerosene and petrol with higher LC50 (8.7 and 8.0 mg/L) in fingerlings of C. gariepinus. High risk to cancer disorders may occur in exposed fish to petroleum with high incidence of fluorene , anthracene, pyrene and benz a anthracene which correlated positively to benzo a pyrene which provide some basis for predicting impact of oil spills on fingerling population.


2021 ◽  
Author(s):  
Wei Li ◽  
Yanzehua Liu ◽  
Dan Li ◽  
Liping Wang ◽  
Zhen Mao ◽  
...  

Abstract The degradation of polycyclic aromatic hydrocarbons has attracted much attention. Based on toluene-catechol-anthracene multi-substrate progressive domestication, a mixed microbial consortium with synergistic metabolic activity was screened from the activated sludge of coking wastewater. High-throughput sequencing showed that the consortium was dominated by Flavobacteriia at the class level, with the proportion increasing from 8.88% to 56.41% after domestication, and that Myroides and Brevundimonas dominated at the genus level, increasing from less than 1% to 55.53% and 12.28%, respectively. Under temperature conditions of 30 °C, a pH of 7, and an initial anthracene concentration of 40 mg L-1, the degradation ratio reached 85.7% just 16 days after inoculation. Degradation ratio of Anthracene (40 mg L-1) via the consortium plus an indigenous strain Pseudomonas_aeruginosa DM3 on the sixth day (83%) equated to that in the control group without DM3 on the 12th day. The first-order rate constant (k=0.240 and 0.159 d-1) was calculated for the anthracene degradation within 10 days, with a corresponding half-life by the consortium of 2.9 days with DM3 and 4.4 days without DM3. The metabolites 1-naphthol, dibutyl phthalate, and 1,2-benzene dicarboxylic acid, mono (2-ethylhexyl) ester were presented in the reaction, inferring the metabolic pathway of phthalic acid. Our work revealed that inoculating the mixed microbial consortium with indigenous Pseudomonas aeruginosa DM3 has the potential for removing polycyclic aromatic hydrocarbons.


2021 ◽  
Vol 11 (17) ◽  
pp. 8021
Author(s):  
Shao-Yang Hu ◽  
Chi-Ying Hsieh ◽  
Hans-Uwe Dahms ◽  
Yu-Hsien Tseng ◽  
Jesse Chen ◽  
...  

The amphipod (Hyalella azteca) and zebrafish (Brachydanio rerio) embryos were used for toxicological sediment porewater testing. Porewaters from 35 sampling stations of eight streams in southern Taiwan were screened for toxic effects and their relationship with 6 metal and 16 polycyclic aromatic hydrocarbons (PAHs). Concentration analysis results showed that the following PAHs, naphththalene, benzo(b)fluoranthene, dibenz(a,h)anthracene, acenaphthalene, and the heavy metal cadmium were not detected in 35 sampling stations. The highest detection rate of 94.1% was caused by the PAHs fluoranthene and pyrene. The highest detection rate of the metal zinc was 88.6% of 35 analyzed samples. The majority of samples (88%) were classified as level tier 1 according to USEPA national sediment inventory. This indicates the probability of adverse effects on aquatic life or human health. The results of a zebrafish embryo test showed that heart rate and survival were significantly reduced with all porewater samples. Therefore, fish exposed to contaminated river conditions may be affected in their cardiovascular functions. Looking at correlations between toxic effects of metals and PAHs, we found that phenanthrene, anthracene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, and benzo(a)pyrene were low, while fluorene was highly correlated with toxic effects of metals.


2019 ◽  
Author(s):  
Ella T. Sieradzki ◽  
Michael Morando ◽  
Jed A. Fuhrman

AbstractBacterial biodegradation is a significant contributor to remineralization of polycyclic aromatic hydrocarbons (PAHs): toxic and recalcitrant components of crude oil as well as byproducts of partial combustion chronically introduced into seawater via atmospheric deposition. The Deepwater Horizon oil spill demonstrated the speed at which a seed PAH-degrading community maintained by low chronic inputs can respond to an acute pollution. We investigated the diversity and functional potential of a similar seed community in the Port of Los Angeles, a chronically polluted site, using stable isotope probing with naphthalene, deep-sequenced metagenomes and carbon incorporation rate measurements at the port and in two sites further into the San Pedro Channel. We show a switch in the composition of the PAH degrading community from diverse early-responding generalists to late-blooming specialized degraders. This switch demonstrates the ability of the local seed community of degraders at the Port of LA to incorporate carbon from PAHs independently of a labile-hydrocarbon degrading succession. We were able to directly show that assembled genomes belonged to naphthalene degraders by matching their 16S-rRNA gene with experimental stable isotope probing data. Surprisingly, we did not find a full PAH degradation pathway in any of those genomes and even when combining genes from the entire microbial community. We use metabolic pathways identified in those genomes to generate metagenomic-based recommendations for future optimization of PAHs bioremediation.


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