Concentrations in human blood of petroleum hydrocarbons associated with the BP/Deepwater Horizon oil spill, Gulf of Mexico

Heat and mass transfer based on the low-temperature thermal treatment of hydrocarbons-impacted soil: A numerical simulation and sandbox validation

Thermal treatment can be an effective method for soil remediation, and numerical models play a crucial role in elucidating the underlying processes that affect efficacy. In this study, experiments were conducted to examine the low-temperature thermal treatment for removing n-hexane and n-octane from soil. The results showed that the removal of two alkanes followed the pseudo-first-order kinetics. Additionally, a quantitative relationship between kinetics constant and temperature was established. Based on experimental results, a simple mathematical model was presented via COMSOL Multiphysics 6.0. The processes considered in the model incorporated conductive and convective heat transfer, the vaporization latent heat, and the removal of organic contaminants which was quantified using an advection-dispersion equation combined with a pseudo-first-order kinetic. The developed model was first validated by a thermal treatment in a soil column, demonstrating conformity with the measured temperature and concentration values. Subsequently, the temporal and spatial changes in soil temperature and contaminant levels were evaluated for different heating temperatures. It was found that thermal conduction dominated heat transfer, whereas thermal convection caused by the migration of liquid water intensified when the temperature was higher than the boiling point. The completion time exhibited a correlation with the heating temperature. It was predicted that the time required to achieve a 90% removal efficiency could be shortened from 14 h to 9.5 h by elevating the heating temperature from 80 ℃ to 120 ℃. The study also investigated the impact of the initial water content on heat transfer. It was observed that the saturated soil showed the slowest heating rate and the longest boiling stage.

Bioremediation of an industrial soil contaminated by hydrocarbons in microcosm system, involving bioprocesses utilizing co-products and agro-industrial wastes

The present study describes practical implication of bioaugmentation and biostimulation processes for bioremediation of an industrial soil chronically contaminated by hydrocarbons. For this purpose, biomass production of six autochthonous hydrocarbon-degrading bacteria were evaluated as inoculum of bioaugmentation strategy, by testing carbon and nitrogen sources included co-products and agro-industrial waste as sustainable and low-cost components of the growth medium. Otherwise, biostimulation was approached by the addition of optimized concentration of nitrogen and phosphorus. Microcosm assays showed that total hydrocarbons (TH) were significantly removed from chronically contaminated soil undergoing bioremediation treatment. Systems Mix (bioaugmentation); N,P (biostimulation) and Mix + N,P (bioaugmentation and biostimulation) reached higher TH removal, being 89.85%, 91.00%, 93.04%, respectively, comparing to 77.83% of system C (natural attenuation) at 90 days. The increased heterotrophic aerobic bacteria and hydrocarbon degrading bacteria counts were according to TH biodegrading process during the experiments. Our results showed that biostimulation with nutrients represent a valuable alternative tool to treat a chronically hydrocarbon-contaminated industrial soil, while bioaugmentation with a consortium of hydrocarbon degrading bacteria would be justified when the soil has a low amount of endogenous degrading microorganisms. Furthermore, the production of inoculum for application in bioaugmentation using low-cost substrates, such as industrial waste, would lead to the development of an environmentally friendly and attractive process in terms of cost-benefit.

Correlation of soil microbiome with crude oil contamination drives detection of hydrocarbon degrading genes which are independent to quantity and type of contaminants

The impacts of crude oil contamination on soil microbial populations were explored in seven different polluted areas near oil and gas drilling sites and refineries of Assam, India. Using high-throughput sequencing techniques, the functional genes and metabolic pathways involved in the bioconversion of crude oil contaminants by the indigenous microbial community were explored. Total petroleum hydrocarbon (TPH) concentrations in soil samples ranged from 1109.47 to 75,725.33 mg/kg, while total polyaromatic hydrocarbon (PAH) concentrations ranged from 0.780 to 560.05 mg/kg. Pyrene, benzo[a]anthracene, naphthalene, phenanthrene, and anthracene had greater quantities than the maximum permitted limits, suggesting a greater ecological risk, in comparison to other polyaromatic hydrocarbons. According to the metagenomic data analysis, the bacterial phyla Proteobacteria, Actinobacteria, Acidobacteria, and Bacteroides were the most prevalent among all polluted areas. The most prominent hydrocarbon degraders in the contaminated sites included Burkholderia, Mycobacterium, Polaromonas, and Pseudomonas. However, the kinds of pollutants and their concentrations did not correlate with the abundances of respective degrading genes for all polluted locations, as some of the sites with little to low PAH contamination had significant abundances of corresponding functional genes for degradation. Thus, the findings of this study imply that the microbiome of hydrocarbon-contaminated areas, which are biologically involved in the degradation process, has various genes, operons and catabolic pathways that are independent of the presence of a specific kind of contaminant.

Volatile organic compounds: A proinflammatory activator in autoimmune diseases

The etiopathogenesis of inflammatory and autoimmune diseases, including pulmonary disease, atherosclerosis, and rheumatoid arthritis, has been linked to human exposure to volatile organic compounds (VOC) present in the environment. Chronic inflammation due to immune breakdown and malfunctioning of the immune system has been projected to play a major role in the initiation and progression of autoimmune disorders. Macrophages, major phagocytes involved in the regulation of chronic inflammation, are a major target of VOC. Excessive and prolonged activation of immune cells (T and B lymphocytes) and overexpression of the master pro-inflammatory constituents [cytokine and tumor necrosis factor-alpha, together with other mediators (interleukin-6, interleukin-1, and interferon-gamma)] have been shown to play a central role in the pathogenesis of autoimmune inflammatory responses. The function and efficiency of the immune system resulting in immunostimulation and immunosuppression are a result of exogenous and endogenous factors. An autoimmune disorder is a by-product of the overproduction of these inflammatory mediators. Additionally, an excess of these toxicants helps in promoting autoimmunity through alterations in DNA methylation in CD4 T cells. The purpose of this review is to shed light on the possible role of VOC exposure in the onset and progression of autoimmune diseases.

Volatile organic compounds released in the mainstream smoke of flavor capsule cigarettes

In this study, the composition of mainstream smoke was investigated with an emphasis on a list of volatile organic compounds (VOCs: e.g., isoprene, acrylonitrile, methyl ethyl ketone, benzene, toluene, m-xylene and styrene) using the two types of flavor capsule cigarettes (FCCs, here coded as F1 and F2) in reference to one commercial, non-flavored (NF) and 3R4F cigarette. The concentrations of all the target compounds from FCCs were quantified under two contrasting conditions (i.e., with and without breaking the capsules). The effect of breaking the capsule was apparent in the FCC products with the enhancement of VOC levels, specifically between after and before breaking the capsules (e.g., 1.10-1.58 folds (benzene) and 1.30-1.53 folds (acetonitrile)). Such increases were apparent in both FCC samples if assessed in terms of the total amount of VOCs (TVOC): (1) F1 (from 2159 to 2530 μg cig-1 (p = 9.42 × 10-6)) and (2) F2 (from 1470 to 2014 μg cig-1 (p = 0.05)). In addition, these TVOC levels determined from the FCCs were 1.62- to 1.83- and 1.29- to 1.46-fold higher than those of the NF cigarette and the 3R4F cigarette, respectively. Thus, these FCC products are suspected to play a role as stronger sources of VOCs than the general cigarette products.

Design of a Microbial Remediation Inoculation Program for Petroleum Hydrocarbon Contaminated Sites Based on Degradation Pathways

This paper analyzed the degradation pathways of petroleum hydrocarbon degradation bacteria, screened the main degradation pathways, and found the petroleum hydrocarbon degradation enzymes corresponding to each step of the degradation pathway. Through the Copeland method, the best inoculation program of petroleum hydrocarbon degradation bacteria in a polluted site was selected as follows: single oxygenation path was dominated by Streptomyces avermitilis, hydroxylation path was dominated by Methylosinus trichosporium OB3b, secondary oxygenation path was dominated by Pseudomonas aeruginosa, secondary hydroxylation path was dominated by Methylococcus capsulatus, double oxygenation path was dominated by Acinetobacter baylyi ADP1, hydrolysis path was dominated by Rhodococcus erythropolis, and CoA path was dominated by Geobacter metallireducens GS-15 to repair petroleum hydrocarbon contaminated sites. The Copeland method score for this solution is 22, which is the highest among the 375 solutions designed in this paper, indicating that it has the best degradation effect. Meanwhile, we verified its effect by the Cdocker method, and the Cdocker energy of this solution is −285.811 kcal/mol, which has the highest absolute value. Among the inoculation programs of the top 13 petroleum hydrocarbon degradation bacteria, the effect of the best inoculation program of petroleum hydrocarbon degradation bacteria was 18% higher than that of the 13th group, verifying that this solution has the best overall degradation effect. The inoculation program of petroleum hydrocarbon degradation bacteria designed in this paper considered the main pathways of petroleum hydrocarbon pollutant degradation, especially highlighting the degradability of petroleum hydrocarbon intermediate degradation products, and enriching the theoretical program of microbial remediation of petroleum hydrocarbon contaminated sites.

The Use of Polymer Membranes to Counteract the Risk of Environmental of Soil and Water Contamination

Chemical, biological, radiological, or nuclear (CBRN) contamination of the environment is a significant threat to human health and life as well as environmental safety. It is then necessary to take actions aimed at minimizing and eliminating the threat. Depending on the type of contamination, various methods are used, including sorption, biodegradation, separation, or ion exchange processes in which membranes play an important role. The type of membrane is selected in respect of both the environment and the type of neutralized pollutants. Therefore, the production and modification of membranes are being adapted to the type of contamination and the purpose of the work. This article presents examples of membranes and their possible applications depending on the part of the environment subject to reclamation and the type of contamination.

Rhizoremediation of hydrocarbon contaminated soil using Luffa aegyptiaca (Mill) and associated fungi

The potentials of Luffa aegyptiaca and its rhizospheric, non-mycorrhizal fungi in biodegrading and bio-remediating hydrocarbon contaminated soil were investigated in-vitro and in-situ. Biodegradation study was done in two stages: preliminary study using hydrocarbon treated filter paper and in-vitro with Mineral Salt Media (MSM) read on Spectrophotometer at two photo synthetically active wavelengths (530 nm and 620 nm) while rhizoremediation study was done in-situ in contaminated plot of land. Hydrocarbon utilization ability of the fungi and plant were confirmed using total petroleum hydrocarbon (TPH) analysis and gas chromatography mass spectroscopy (GC-MS). Results show differing rates of hydrocarbon utilization by isolated fungi. In-vitro biodegradation study showed that Aspergillus niger, Fusarium solani, Curvularia lunata and Trichoderma harzianum were best in degrading kerosene (78%), diesel (70%), spent engine oil (83%) and crude oil (77%) respectively. Rhizoremediation study using L. aegyptiaca and C. lunata show that remediation was enhanced to 72.15% as against 32.32% and 14% when only the plant or fungus is used respectively. Hydrocarbon accumulation by L. aegyptiaca also decreased in the presence of the fungus. Curvularia lunata is shown in this study to enhance the germination, survival, growth and bioremediation efficiency of L. aegyptiaca in polluted environment.Novelty statement The potentials of Curvularia lunata, a non-mycorrhizal fungi associated with L. aegyptiaca in survival, growth and phytoremediation of petroleum hydrocarbon polluted soil by L. aegyptiaca is highlighted in this study. Luffa aegyptiaca and its associated fungi is shown to bio-remediate petroleum hydrocarbon through phyto-accumulation and rhizosphere effect.

Streptomyces sp. S501, a Marine Petroleum-Degrading Actinobacterium Isolated from Sediment of Yalujiang Estuary, Northern China, and Its Genome Annotation

Streptomyces sp. S501, which was isolated from the sediment of Yalujiang Estuary in China, was the first marine Streptomyces species discovered to act as an excellent petroleum degrader. We analyzed the effect of pH, temperature, and concentration of NH₄NO₃ on the petroleum degradation of strain S501, and the optimum biodegradation rate reached 63.02% under the condition of 2 g/L NH₄NO₃ addition at 30 °C and pH 8. The complete genome sequence of Streptomyces sp. S501 was determined by using the PacBio RSII platform, which contains a linear chromosome with 7,173,651 bp and a linear plasmid with 288,181 bp, with GC contents of 71.19% and 67.57%, respectively. The genome sequence suggests that Streptomyces sp. S501 has the ability to degrade several hazardous pollutants, as well as the ability to biosynthesize diverse secondary metabolites and enzymes. There are fifty annotated genes involved in oil component degradation, and there are three genes without known annotation information in Streptomyces sp. S501, which have high homology with genes encoding P450 family enzymes and should be novel genes involved in alkane degradation. This study provides useful genetic information for investigating the molecular mechanisms of marine Streptomyces, with biodegradation and application potential.

Combination of rhamnolipid and biochar in assisting phytoremediation of petroleum hydrocarbon contaminated soil using Spartina anglica

Biochar (BC) and rhamnolipid (RL) is used in bioremediation of petroleum hydrocarbons, however, the combined effect of BC and RL in phytoremediation has not been studied until now. In this paper, the phytoremediation of petroleum hydrocarbon-contaminated soil using novel plant Spartina anglica was enhanced by the combination of biochar (BC) and rhamnolipid (RL). Samples of petroleum-contaminated soil (10, 30 and 50 g/kg) were amended by BC, BC+ RL and rhamnolipid modified biochar (RMB), respectively. After 60 day's cultivation, the removal rate of total petroleum hydrocarbons (TPHs) for unplanted soil (UP), planted soil (P), planted soil with BC addition (P-BC), planted soil with BC and RL addition (P-BC + RL) and planted soil with addition of RMB (P-RMB) were 8.6%, 19.1%, 27.7%, 32.4% and 35.1% in soil with TPHs concentration of 30 g/kg, respectively. Compared with UP, the plantation of Spartina anglica significantly decreased the concentration of C_8-14 and tricyclic PAHs. Furthermore, the application of BC and RMB alleviated the toxicity of petroleum hydrocarbons to Spartina anglica via improving plant growth with increasing plant height, root vitality and total chlorophyll content. High-throughput sequencing result indicated that rhizosphere microbial community of Spartina anglica was regulated by the application of BC and RMB, with increase of bacteria and plant mycorrhizal symbiotic fungus in biochar and RMB amended soil.

Predictors of blood volatile organic compound levels in Gulf coast residents

To address concerns among Gulf Coast residents about ongoing exposures to volatile organic compounds, including benzene, toluene, ethylbenzene, o-xylene, and m-xylene/p-xylene (BTEX), we characterized current blood levels and identified predictors of BTEX among Gulf state residents. We collected questionnaire data on recent exposures and measured blood BTEX levels in a convenience sample of 718 Gulf residents. Because BTEX is rapidly cleared from the body, blood levels represent recent exposures in the past 24 h. We compared participants' levels of blood BTEX to a nationally representative sample. Among nonsmokers we assessed predictors of blood BTEX levels using linear regression, and predicted the risk of elevated BTEX levels using modified Poisson regression. Blood BTEX levels in Gulf residents were similar to national levels. Among nonsmokers, sex and reporting recent smoky/chemical odors predicted blood BTEX. The change in log benzene was -0.26 (95% CI: -0.47, -0.04) and 0.72 (0.02, 1.42) for women and those who reported odors, respectively. Season, time spent away from home, and self-reported residential proximity to Superfund sites (within a half mile) were statistically associated with benzene only, however mean concentration was nearly an order of magnitude below that of cigarette smokers. Among these Gulf residents, smoking was the primary contributor to blood BTEX levels, but other factors were also relevant.

A three year study of metal levels in skin biopsies of whales in the Gulf of Mexico after the Deepwater Horizon oil crisis

In response to the explosion of the Deepwater Horizon and the massive release of oil that followed, we conducted three annual research voyages to investigate how the oil spill would impact the marine offshore environment. Most investigations into the ecological and toxicological impacts of the Deepwater Horizon Oil crisis have mainly focused on the fate of the oil and dispersants, but few have considered the release of metals into the environment. From studies of previous oil spills, other marine oil industries, and analyses of oil compositions, it is evident that metals are frequently encountered. Several metals have been reported in the MC252 oil from the Deepwater Horizon oil spill, including the nonessential metals aluminum, arsenic, chromium, nickel, and lead; genotoxic metals, such as these are able to damage DNA and can bioaccumulate in organisms resulting in persistent exposure. In the Gulf of Mexico, whales are the apex species; hence we collected skin biopsies from sperm whales (Physeter macrocephalus), short-finned pilot whales (Globicephala macrorhynchus), and Bryde's whales (Balaenoptera edeni). The results from our three-year study of monitoring metal levels in whale skin show (1) genotoxic metals at concentrations higher than global averages previously reported and (2) patterns for MC252-relevant metal concentrations decreasing with time from the oil spill.

Effect of different enrichment strategies on microbial community structure in petroleum-contaminated marine sediment in Dalian, China

An oil spill occurred at Xingang Port, Dalian, China in 2010. Four years after this spill, oil contamination was still detected in samples collected nearby. In this study, the strains that evolved in the sediment were screened by high-throughput sequencing technology. Most of these strains were genera reported to have functions associated with crude oil biodegradation. The diversities and numbers of microbes were monitored through enrichment culturing; the dominant strains propagated at first, but the enrichment could not be continued, which indicated that the prolonged culture was not effective in the enrichment of the micro-consortium. Oxygen was also observed to affect the propagation of the dominant microbes. The results showed the role of culture strategies and oxygen in the enrichment of the petroleum-degrading microbes. Therefore, dominant strains could be screened by optimizing both the enrichment time and oxygen concentration used for culturing to facilitate oil biodegradation in the marine ecosystem.