Biodegradation of aliphatic and aromatic hydrocarbons by bacteria isolated from Bahregan area.

Environmental pollution with aromatic and aliphatic hydrocarbons caused by oil and petrochemical industries has very toxic and carcinogenic effects on living organisms and should be removed from the environment. In this research, after analyzing the oil sludge of the Bahregan area, it was found that most aliphatic paraffin compounds are related to octadecane, most liquid aliphatic compounds are related to hexadecane, and most aromatic compounds are related to naphthalene, phenanthrene, fluoranthene, and anthracene. Then, we investigated the ability of native bacteria from this area, such as Thalassospira, Chromohalobacter, and a bacterial consortium, to biodegrade the dominant aromatic and aliphatic hydrocarbons found in oil sludge. The results of Gas Chromatography-Mass Spectrometry analysis showed that among the tested hydrocarbon sources, Thalassospira can completely remove octadecane and hexadecane, and Chromohalobacter can reduce hexadecane from 15.9 to 9.9%. The bacterial consortium can completely remove octadecane and reduce hexadecane from 15.9 to 5.1%, toluene from 25.6 to 0.6%, and phenanthrene from 12.93 to 6%. According to the obtained results, the bacterial consortium effectively plays a role in the biodegradation of aromatic and aliphatic hydrocarbons, making it a viable solution for treating hydrocarbon pollutants in various environments.

Bacterial crude oil and polyaromatic hydrocarbon degraders from Kazakh oil fields as barley growth support.

Bacterial strains of the genera Arthrobacter, Bacillus, Dietzia, Kocuria, and Micrococcus were isolated from oil-contaminated soils of the Balgimbaev, Dossor, and Zaburunye oil fields in Kazakhstan. They were selected from 1376 isolated strains based on their unique ability to use crude oil and polyaromatic hydrocarbons (PAHs) as sole source of carbon and energy in growth experiments. The isolated strains degraded a wide range of aliphatic and aromatic components from crude oil to generate a total of 170 acid metabolites. Eight metabolites were detected during the degradation of anthracene and of phenanthrene, two of which led to the description of a new degradation pathway. The selected bacterial strains Arthrobacter bussei/agilis SBUG 2290, Bacillus atrophaeus SBUG 2291, Bacillus subtilis SBUG 2285, Dietzia kunjamensis SBUG 2289, Kocuria rosea SBUG 2287, Kocuria polaris SBUG 2288, and Micrococcus luteus SBUG 2286 promoted the growth of barley shoots and roots in oil-contaminated soil, demonstrating the enormous potential of isolatable and cultivable soil bacteria in soil remediation. KEY POINTS: • Special powerful bacterial strains as potential crude oil and PAH degraders. • Growth on crude oil or PAHs as sole source of carbon and energy. • Bacterial support of barley growth as resource for soil remediation.

Simultaneous removal of aliphatic and aromatic crude oil hydrocarbons by Pantoea agglomerans isolated from petroleum-contaminated soil in the west of Iran.

Hydrocarbons are considered as one of the most common and harmful environmental pollutants affecting human health and the environment. Bioremediation as an environmentally friendly, highly efficient, and cost-effective method in remediating oil-contaminated environments has been interesting in recent decades. In this study, hydrocarbon degrader bacterial strains were isolated from the highly petroleum-contaminated soils in the Dehloran oil field in the west of Iran. Out of 37 isolates, 15 can grow on M9 agar medium that contains 1.5 g L-1 of crude oil as the sole carbon source. The morphological, biochemical, and 16SrRNA sequencing analyses were performed for the isolates. The choosing of the isolates as the hydrocarbon degrader was examined by evaluating the efficacy of their crude oil removal at a concentration of 10 g L-1 in an aqueous medium. The results showed that five isolates belonging to Pseudomonas sp., Pseudomonas oryzihabitans, Roseomonas aestuarii, Pantoea agglomerans, and Arthrobacter sp. had a hyper hydrocarbon-degrading activity and they could remove more than 85% of the total petroleum hydrocarbon (TPH) after 96 h. The highest TPH removal of about 95.75% and biodegradation rate of 0.0997 g L-1 h-1 was observed for P. agglomerans. The gas chromatography-mass spectroscopy (GC-MS) analysis was performed during the biodegradation process by P. agglomerans to detect the degradation intermediates and final products. The results confirmed the presence of intermediates such as alcohols and fatty acids in the terminal oxidation pathway of alkanes in this biodegradation process. A promising P. agglomerans NB391 strain can remove aliphatic and aromatic hydrocarbons simultaneously.

Catalytic flash pyrolysis of Scenedesmus sp. post-extraction residue using low-cost HZSM-5 catalyst with the perspective to produce renewable aromatic hydrocarbons.

Recovering renewable chemicals from de-fatted microalgal residue derived from lipid extraction within the algal-derived biofuel sector is crucial, given the rising significance of microalgal-derived biodiesel as a potential substitute for petroleum-based liquid fuels. As a circular economy strategy, effective valorization of de-fatted biomass significantly improves the energetic and economic facets of establishing a sustainable algal-derived biofuel industry. In this scenario, this study investigates flash catalytic pyrolysis as a sustainable pathway for valorizing Scenedesmus sp. post-extraction residue (SPR), potentially yielding a bio-oil enriched with upgraded characteristics, especially renewable aromatic hydrocarbons. In the scope of this study, volatile products from catalytic and non-catalytic flash pyrolysis were characterized using a micro-furnace type temperature programmable pyrolyzer coupled with gas chromatographic separation and mass spectrometry detection (Py-GC/MS). Flash pyrolysis of SPR resulted in volatile products with elevated oxygen and nitrogen compounds with concentrations of 46.4% and 26.4%, respectively. In contrast, flash pyrolysis of lyophilized microalgal biomass resulted in lower concentrations of these compounds, with 40.9% oxygen and 17.3% nitrogen. Upgrading volatile pyrolysis products from SPR led to volatile products comprised of only hydrocarbons, while completely removing oxygen and nitrogen-containing compounds. This was achieved by utilizing a low-cost HZSM-5 catalyst within a catalytic bed at 500 °C. Catalytic experiments also indicate the potential conversion of SPR into a bio-oil rich in monocyclic aromatic hydrocarbons, primarily BETX, with toluene comprising over one-third of its composition, thus presenting a sustainable pathway for producing an aromatic hydrocarbon-rich bio-oil derived from SPR. Another significant finding was that 97.8% of the hydrocarbon fraction fell within the gasoline range (C5-C12), and 35.5% fell within the jet fuel range (C8-C16). Thus, flash catalytic pyrolysis of SPR exhibits significant promise for application in drop-in biofuel production, including green gasoline and bio-jet fuel, aligning with the principles of the circular economy, green chemistry, and bio-refinery.

Acidovorax benzenivorans sp. nov., a novel aromatic hydrocarbon-degrading bacterium isolated from a xylene-degrading enrichment culture.

A Gram-stain-negative strain, designated as D2M1T was isolated from xylene-degrading enrichment culture and characterized using a polyphasic approach to determine its taxonomic position. The 16S rRNA gene sequence analysis revealed that strain D2M1T belongs to the genus Acidovorax, with the highest 16S rRNA gene similarity to Acidovorax delafieldii DSM 64T (99.93 %), followed by Acidovorax radicis DSM 23535T (98.77 %) and Acidovorax kalamii MTCC 12652T (98.76 %). The draft genome sequence of strain D2M1T is 5.49 Mb long, and the G+C content of the genome is 64.2 mol%. Orthologous average nucleotide identity and digital DNA-DNA hybridization relatedness values between strain D2M1T and its closest relatives were below the threshold values for species demarcation confirming that strain D2M1T is distinctly separated from its closest relatives. The whole genome analysis of the strain revealed a phenol degradation gene cluster, encoding a multicomponent phenol hydroxylase (mPH) together with a complete meta-cleavage pathway including an I.2.C-type catechol 2,3-dioxygenase (C23O) gene. The strain was able to degrade benzene and ethylbenzene as sole sources of carbon and energy under aerobic and microaerobic conditions. Cells were facultatively aerobic rods and motile with a single polar flagellum. The predominant fatty acids (>10 % of the total) of strain D2M1T were summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c). The major ubiquinone of strain D2M1T was Q8, while the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Based on polyphasic data, it is concluded that strain D2M1T represents a novel species of the genus Acidovorax, for which the name of Acidovorax benzenivorans sp. nov. is proposed. The type strain of the species is strain D2M1T (=DSM 115238T=NCAIM B.02679T).

Advanced separation of mineral oil aromatic hydrocarbons by number of aromatic rings using donor-acceptor-complex chromatography to extend on-line coupled liquid chromatography-gas chromatography.

An automated implementation for a subfractionation of mineral oil aromatic hydrocarbons (MOAH) into a mono-/di-aromatic fraction (MDAF) and a tri-/poly-aromatic fraction (TPAF) is presented, which is highly demanded by the European Food Safety Authority (EFSA) respecting the genotoxic and carcinogenic potential of MOAH. For this, donor-acceptor-complex chromatography (DACC) was used as a selective stationary phase to extend the conventional instrumental setup for the analysis of mineral oil hydrocarbons via on-line coupled liquid chromatography-gas chromatography-flame ionization detection (LC-GC-FID). A set of six new internal standards was introduced for the verification of the MOAH fractionation and a quantification of MDAF and TPAF, respectively. The automated DACC approach was applied to representative petrochemical references as well as to food samples, such as rice and infant formula, generally showing well conformity with results obtained by state-of-the-art analysis using two-dimensional GC (GCxGC). Relative deviations of DACC/LC-GC-FID compared to GCxGC-FID methods regarding the ≥ 3 ring MOAH content ranged between -50 and +6 % (median: -2 %, all samples, only values above limit of quantification). However, crucial deviations mainly result from "border-crossing" substances, e.g., dibenzothiophenes or partially hydrogenated MOAH. These substances can cause overestimations of ≥ 3 ring MOAH fraction during GCxGC analysis due to co-elution, which is mostly avoided using the DACC approach. Furthermore, the DACC approach can help to minimize underestimations of toxicologically relevant ≥ 3 ring MOAH caused by an unavoidable loss of MOAH during epoxidation, since natural olefins, such as terpenes, predominantly elute in MDAF, which was exemplarily shown for an olive oil and a terpene reference. The presented approach can be implemented easily in existing LC-GC-FID setup for an automated and advanced screening of MOAH to lower the need for elaborate GCxGC analysis also in routine environments.

Aromatic Hydrocarbon Receptor Repressor (AHRR) is a biomarker of ambient air pollution exposure and Coronary Artery Disease (CAD).

Two hundred and twenty subjects were recruited while undergoing cardiac catheterization. AHRR cg05575921 methylation was shown to be significantly decreased in ever smokers compared to never smokers (Mean± SD = 64.2 ± 17.2 vs 80.1 ± 11.1 respectively; P < 0.0001). In addition, higher urinary levels of 2-OHNAP and 2-OHFLU were significantly associated with more AHRR cg05575921 hypomethylation, even after correcting for smoking (ß[95%CI]= -4.161[-7.553, -0.769]; P = 0.016 and -5.190[-9.761, -0.618]; P = 0.026, respectively) but not 1-OHPYR (ß[95%CI]= -3.545 [-10.935, 3.845]; P = 0.345). Additionally, hypomethylation of AHRR ROI was significantly associated with obstructive coronary artery disease (CAD) after adjusting for smoking, age, sex, diabetes and dyslipidemia (OR [95%CI] = 1.024[1.000 - 1.048]; P = 0.046). Results of this study necessitate further validation to potentially consider clinical incorporation of AHRR methylation status as an early predictive biomarker for the potential association between ambient air pollution and CAD.

Effects of aromatic hydrocarbons and evaluation of oil toxicity modelling for larvae of a tropical coral.

Application of oil toxicity modelling for assessing the risk of spills to coral reefs remains uncertain due to a lack of data for key tropical species and environmental conditions. In this study, larvae of the coral Acropora millepora were exposed to six aromatic hydrocarbons individually to generate critical target lipid body burdens (CTLBBs). Larval metamorphosis was inhibited by all six aromatic hydrocarbons, while larval survival was only affected at concentrations >2000 µg L-1. The derived metamorphosis CTLBB of 9.7 µmol g-1 octanol indicates larvae are more sensitive than adult corals, and places A. millepora larvae among the most sensitive organisms in the target lipid model (TLM) databases. Larvae were also more sensitive to anthracene and pyrene when co-exposed to ecologically relevant levels of ultraviolet radiation. The results suggest that the application of the phototoxic TLM would be protective of A. millepora larvae, provided adequate chemical and light data are available.

Holistic approach to waste mobil oil bioremediation: Valorizing waste through biosurfactant production for soil restoration.

The combustion of mobil oil leads to the emission of toxic compounds in the environment. In this study, the aromatic and aliphatic hydrocarbon fractions present in a waste mobil oil collected from automobile market were comprehensively identified and their toxicity was evaluated using wheat grain. Lysinibacillus sphaericus strain IITR51 isolated and characterized previously could degrade 30-80% of both aliphatic and aromatic hydrocarbons in liquid culture. Interestingly, the strain IITR51 produced 627 mg/L of rhamnolipid biosurfactant by utilizing 3% (v/v) of waste mobil oil in the presence of 1.5% glycerol as additional carbon source. In a soil microcosm study by employing strain IITR51, 50-86% of 3-6 ring aromatic hydrocarbons and 63-98% of aliphatic hydrocarbons (C8 to C22) were degraded. Addition of 60 µg/mL rhamnolipid biosurfactant enhanced the degradation of both aliphatic and aromatic hydrocarbons from 76.88% to 61.21%-94.11% and 78.27% respectively. The degradation of mobil oil components improved the soil physico-chemical properties and increased soil fertility to 64% as evident by the phytotoxicity assessments. The findings indicate that strain IITR51 with degradation capability coupled with biosurfactant production could be a candidate for restoring hydrocarbon contaminated soils.

Assessing the half-life and degradation kinetics of aliphatic and aromatic hydrocarbons by bacteria isolated from crude oil contaminated soil.

Pollution from the oil industries and refineries has worsened various environmental compartments. In this study, indigenous oil degrading bacteria were isolated from crude oil obtained from an Oil and Natural Gas Corporation (ONGC) asset in Ankleshwar, Gujarat, India. Based on 16S rRNA phylogeny, they were identified as Pseudomonas boreopolis IITR108, Microbacterium schleiferi IITR109, Pseudomonas aeruginosa IITR110, and Bacillus velezensis IITR111. The strain IITR108, IITR109, IITR110, and IITR111 showed 80-89% and 71-78% degradation of aliphatic (C8-C40) and aromatic (4-5 ring) hydrocarbons respectively in 45 d when supplemented with 3% (v/v) waste crude oil. When compared to individual bacteria, the consortium degrades 93.2% of aliphatic hydrocarbons and 85.5% of polyaromatic hydrocarbons. It was observed that the total aliphatic and aromatic content of crude oil 394,470 µg/mL and 47,050 µg/mL was reduced up to 9617.75 µg/mL and 4586 µg/mL respectively in 45 d when consortium was employed. The rate kinetics analysis revealed that the biodegradation isotherm followed first order kinetics, with a linear correlation between concentration (hydrocarbons) and time intervals. The half-life of aliphatic (C8-C40) and aromatic hydrocarbons ranged from 200 to 453 h and 459-714 h respectively. All the bacteria efficiently produced catabolic enzymes such as alkane monooxygenase, alcohol dehydrogenase, and lipase during the degradation of crude oil. These findings indicated that the bacterial consortium can be a better candidate for bioremediation and reclamation of aliphatic and aromatics hydrocarbon contaminated sites.

Lignin and spent bleaching clay into mono-aromatic hydrocarbons by a cascade dual catalytic pyrolysis system: Critical role of spent bleaching clay.

In the present study, a cascade dual catalytic system was used for the co-pyrolysis of lignin with spent bleaching clay (SBC) to efficiently produce mono-aromatic hydrocarbon (MAHs). The cascade dual catalytic system is composed of calcined SBC (CSBC) and HZSM-5. In this system, SBC not only acts as a hydrogen donor and catalyst in the co-pyrolysis process, but is also used as a primary catalyst in the cascade dual catalytic system after recycling the pyrolysis residues. The effects of different influencing factors (i.e., temperature, CSBC-to-HZSM-5 ratio, and raw materials-to-catalyst ratio) on the system were explored. It was observed that, when the temperature was 550 °C, the CSBC-to-HZSM-5 ratio was 1:1, and when the raw materials-to-catalyst ratio was 1:2, the highest bio-oil yield was 21.35 wt%. The relative MAHs content in bio-oil was 73.34 %, whereas the relative polycyclic aromatic hydrocarbons (PAHs) content was 23.01 %. Meanwhile, the introduction of CSBC inhibited the generation of graphite-like coke as indicated by HZSM-5. This study realizes the full resource utilization of spent bleaching clay and reveals the environmental hazards caused by spent bleaching clay and lignin waste.

Crude oil exposure of early life stages of Atlantic haddock suggests threshold levels for developmental toxicity as low as 0.1 µg total polyaromatic hydrocarbon (TPAH)/L.

Atlantic haddock (Melanogrammus aeglefinus) embryos bind dispersed crude oil droplets to the eggshell and are consequently highly susceptible to toxicity from spilled oil. We established thresholds for developmental toxicity and identified any potential long-term or latent adverse effects that could impair the growth and survival of individuals. Embryos were exposed to oil for eight days (10, 80 and 300 µg oil/L, equivalent to 0.1, 0.8 and 3.0 µg TPAH/L). Acute and delayed mortality were observed at embryonic, larval, and juvenile stages with IC50 = 2.2, 0.39, and 0.27 µg TPAH/L, respectively. Exposure to 0.1 µg TPAH/L had no negative effect on growth or survival. However, yolk sac larvae showed significant reduction in the outgrowth (ballooning) of the cardiac ventricle in the absence of other extracardiac morphological defects. Due to this propensity for latent sublethal developmental toxicity, we recommend an effect threshold of 0.1 µg TPAH/L for risk assessment models.

Combined Omics Approach Reveals Key Differences between Aerobic and Microaerobic Xylene-Degrading Enrichment Bacterial Communities: Rhodoferax─A Hitherto Unknown Player Emerges from the Microbial Dark Matter.

Among monoaromatic hydrocarbons, xylenes, especially the ortho and para isomers, are the least biodegradable compounds in oxygen-limited subsurface environments. Although much knowledge has been gained regarding the anaerobic degradation of xylene isomers in the past 2 decades, the diversity of those bacteria which are able to degrade them under microaerobic conditions is still unknown. To overcome this limitation, aerobic and microaerobic xylene-degrading enrichment cultures were established using groundwater taken from a xylene-contaminated site, and the associated bacterial communities were investigated using a polyphasic approach. Our results show that the xylene-degrading bacterial communities were distinctly different between aerobic and microaerobic enrichment conditions. Although members of the genus Pseudomonas were the most dominant in both types of enrichments, the Rhodoferax and Azovibrio lineages were only abundant under microaerobic conditions, while Sphingobium entirely replaced them under aerobic conditions. Analysis of a metagenome-assembled genome of a Rhodoferax-related bacterium revealed aromatic hydrocarbon-degrading ability by identifying two catechol 2,3-dioxygenases in the genome. Moreover, phylogenetic analysis indicated that both enzymes belonged to a newly defined subfamily of type I.2 extradiol dioxygenases (EDOs). Aerobic and microaerobic xylene-degradation experiments were conducted on strains Sphingobium sp. AS12 and Pseudomonas sp. MAP12, isolated from the aerobic and microaerobic enrichments, respectively. The obtained results, together with the whole-genome sequence data of the strains, confirmed the observation that members of the genus Sphingobium are excellent aromatic hydrocarbon degraders but effective only under clear aerobic conditions. Overall, it was concluded that the observed differences between the bacterial communities of aerobic and microaerobic xylene-degrading enrichments were driven primarily by (i) the method of aromatic ring activation (monooxygenation vs dioxygenation), (ii) the type of EDO enzymes, and (iii) the ability of degraders to respire utilizing nitrate.

Investigation of the effect of refining on the presence of targeted mineral oil aromatic hydrocarbons in coconut oil.

The goal of this work was to investigate the impact of refining on coconut oil particularly on the most toxicologically relevant fraction of the mineral oil aromatic hydrocarbon (MOAH) contamination, namely the fraction composed by the three to seven aromatic rings. A fully integrated platform consisting of a liquid chromatography (LC), a comprehensive multidimensional gas chromatography (GC) (LC-GC × GC) and flame ionization detector (FID) was used to obtained a more detailed characterization of the MOAH sub-classes distribution. The revised EN pr 16995:2017-08 official method was used for preparing the samples, both with and without the auxiliary epoxidation step. Crude coconut oil was spiked with different MOAH standards, namely naphthalenes, alkylated naphthalenes, benzo(a)pyrene, and its alkylated homologues. Refining was modelled by deodorization at 230 °C, stripping with 10 kg/h of steam under 1 mbar vacuum for 3 h. Complete removal of the naphthalenes and reduction of more than 98.8% of the benzo(a)pyrenes was observed. Epoxidation had a significant impact on the MOAH fraction with more than three rings, but with a high dependency on the sample matrix, being significantly less evident in the refined samples than in the crude ones.

In situ microcosm remediation of polyaromatic hydrocarbons: influence and effectiveness of Nano-Zero Valent Iron and activated carbon.

Nano-zero-valent iron (nZVI) and activated carbon (AC) addition are ongoing techniques for the remediation of hydrophobic organic compound-contaminated sediment and water, but with still unexplored eco(toxico)logical implications, especially when applied in situ. In this study, we investigated AC and nZVI as remediation methods for marine contaminated sediment and water, including chemical and toxicity (Artemia franciscana survival and genotoxicity) surveys. The removal efficiency of AC and nZVI (about 99%) was similar in both sediment and seawater, while the survival of nauplii and adults was mainly impacted by nZVI than AC. At the molecular level, the nZVI-addition induced down-regulation in the expression of two stress and one developmental genes, whereas AC was able to up-regulated only one gene involved in stress response. Results suggested that the use of AC is safer than nZVI that requires further investigation and potential optimization to reduce secondary undesired effects.

A study on the impact of harvesting operations on the mineral oil contamination of olive oils.

During the 2020-21 olive oil campaign, the contribution of harvesting operations to mineral oil saturated (MOSH) and aromatic hydrocarbon (MOAH) contamination was studied. Oils extracted from hand-picked olives (15 different olive groves) generally had background MOSH (<2.7 mg/kg), and no quantifiable MOAH. In 40% of the cases, an important contamination increase was observed after harvesting operations. Except for one sample (325.8 and 111.0 mg/kg of MOSH and MOAH, respectively), other samples reached 4.3-33.7 mg/kg of MOSH and 1.1-11.3 mg/kg of MOAH. Accidental leaks of lubricants and/or contact with lubricated mechanical parts, were identified as important sources of contamination. Chromatographic traces obtained by on-line high-performance liquid chromatography (HPLC)-gas chromatography (GC)-flame ionization detection (FID) allowed for source identification. A comprehensive two-dimensional gas chromatographic platform (GC × GC) with parallel FID/MS detection was implemented for confirmation and to attempt the characterization of the contaminations. Good harvesting practices are suggested to minimize contamination risks.

Polyaromatic Hydrocarbon Specific Ring Hydroxylating Dioxygenases: Diversity, Structure, Function, and Protein Engineering.

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitously present in the environment. These compounds have demonstrated both mutagenic and carcinogenic properties. In the past few decades, scientists have constantly been looking for a possible route to their biological degradation. Bacterial ring hydroxylating dioxygenases (RHDs) implicated in the polycyclic aromatic hydrocarbon degradation comprise a large family of enzymes. RHD catalyzes the stereospecific oxidation of PAHs by incorporating molecular oxygen into inert aromatic nuclei. These biocatalysts hold the potential to completely transform and mineralize toxic forms of these compounds into non-toxic forms. RHDsmediated oxygenation produces cis-dihydrodiols, a chiral compound used in pharmaceutical industries. The Molecular investigation of 16S rRNA and key functional genes involved in pollutant degradation have revealed the dominant occurrence of phylum proteobacteria and actinobacteria in hydrocarbonpolluted environments. The present review is aimed at narrating the diversity, distribution, structural and functional characteristics of RHDs. The review further highlights key amino acids participating in RHDs catalysis. It also discusses the robustness of protein engineering methods in improving the structural and functional activity of the ring hydroxylating dioxygenases.

Combination of Multidimensional Instrumental Analysis and the Ames Test for the Toxicological Evaluation of Mineral Oil Aromatic Hydrocarbons.

Mineral oil aromatic hydrocarbons (MOAHs) include mutagenic and carcinogenic substances and are considered a potential health risk. Current methods address the total MOAH content but cannot address the actual toxicological hazard of individual components. This work presents a combined methodology closing those gaps: high-performance liquid chromatography (HPLC) coupled to gas chromatography with flame ionization detection was used to determine the MOAH content. To characterize present substance classes, comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry was applied. Preparative HPLC separated MOAHs into subgroups, which were tested with a miniaturized Ames test evaluating DNA reactivity of isolated fractions. Combining these methods allowed a correlation between present subgroups and DNA reactivity. The developed approach was applied to a mineral oil and distinguished between not DNA-reactive mono- and diaromatics and DNA-reactive tri- and polyaromatics, providing a proof of concept. Hereinafter, it will be applied to diverse sample matrices including mineral oils, food, and food contact materials.

[Characterization of VOCs Emissions from Caged Broiler House in Winter].

Volatile organic compound (VOCs) emissions from poultry and livestock facilities affect the surrounding environmental quality and human health. However, VOCs emissions from broiler houses have been less characterized, and studies of related dominant odorants, carcinogenic risk, and ozone formation potential are still lacking. To fill this research gap, VOCs pollutants emitted from a broiler house were investigated in this study. The VOCs emission characteristics of the broiler house during three different periods of broiler growth (early, middle, and later) were analyzed using gas chromatography-mass spectrometry. The results showed that 77 types of VOCs were detected, including 16 types of halogenated hydrocarbons, 21 types of alkanes, 5 types of olefins, 12 types of aromatic hydrocarbons, 15 types of oxygenated volatile organic compounds (OVOCs), and 8 types of sulfides. During the entire 42-day growth period, the concentrations of halogenated hydrocarbons, alkanes, olefin, aromatic hydrocarbons, and OVOCs in the broiler house showed few changes. However, with the growth of broilers, the intake of sulfur-containing amino acids and the fecal emission coefficient increased, resulting in the gradual conversion of the VOCs to sulfide. Therefore, emissions of sulfur-containing VOCs increased in the early and middle growth periods. Moreover, the increase in ventilation in the house during the later growth period resulted in a decrease in the sulfur-containing VOCs concentrations. The dominant odorants in the broiler house were naphthalene, ethyl acetate, acetaldehyde, carbon disulfide, dimethyl disulfide, methanethiol, methanethiol, and thiophene. Methanethiol had the highest odorous values, ranging from 2172.4 to 19090.9. Meanwhile, there were acceptable levels of carcinogenic risk in the early and middle growth periods, with a lifetime cancer risk (LCR) of 7.7×10-6 and 4.5×10-6, respectively. The average ozone formation potential (OFP) was (1458.9±787.4) µg·m-3. The results of this study can provide a scientific basis for the monitoring of malodorous substances and formulation of emission reduction strategies in broiler production.