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A laboratory study of particulate and gaseous emissions from crude oil and crude oil-dispersant contaminated seawater due to breaking waves
Abstract
Crude oil spill incidents occur frequently causing a verity of occupational, ecological and environmental problems. Dispersants are applied to enhance the dispersion rate of crude oil slicks into the water column. In this study, the aerosol size distribution from 10 nm to 20 μm, total particle-bound aromatic hydrocarbons (pPAH) and volatile organic compounds (VOCs) are measured in a 6 x 0.3 x 0.6 m tank as plunging breaking waves entrain oil slicks. The experiments are performed for seawater with slicks of crude oil, crude oil-dispersant mixture and dispersant only. The measurements investigate the effects of wave energy and slick properties on the temporal evolution of the emissions. The total number concentrations of particles originating from the oil-dispersant mixture are 1–2 orders of magnitude higher than those of crude oil across the entire nano-scale range, reaching 100x for 20 nm particles. Conversely, the differences in concentration are small in the micron range. The average concentrations of pPAH are variable but similar (150–270 ng/m³). The VOC concentrations for crude oil-dispersant mixtures are 2–3 times lower than those of crude oil, presumably due to the surfactant effect on mass diffusion. The drastic increase in ultrafine particle concentrations may raise concerns about effects of inhalation by cleanup workers and downstream communities though VOC emissions reduce. Findings through this study provide insight into how the spray of dispersant may change the ratio of airborne particulate matter and VOC emissions from seawater due to natural processes.
... Crude oil, apart from being an ever-increasing demand of global industry (Herrera et al., 2018;Kilian and Murphy, 2014), is also recognised as one of the major origin of pollutants detected in terrestrial (Rajabi and Sharifipour, 2018), atmospheric (Afshar-Mohajer et al., 2018) and ocean ecosystem (Afshar-Mohajer et al., 2019). The world proven crude oil reserves have been estimated to be N1000 billion barrels (bb) in 1997 and 1498 bb at the end of 2018 (≈44% during the last 20 years) (OPEC, 2019) which demonstrates the global desire and need to recover more crude oil for energy, transport, material and manufacturing purposes. ...
... In the last three decades, the Crude oil VOC Emissions (hereafter CVEs), have been investigated in literature either directly by means of laboratory and field-based analyses or indirectly via emission inventories (EIs) of the petroleum industry to regulate their contributions to the atmospheric pollutions (Table 1). However, only a few studies have focused on analysing the major mechanisms of CVEs and their influential parameters under different conditions such as water soluble fraction of HCs in crude oil contaminated soil (Saeed and Al-Mutairi, 2000;Saeed et al., 2013), ocean oil spillage (Afshar-Mohajer et al., 2018;Hanna and Drivas, 1993;Tonacci et al., 2015) and contaminated lands (Yang et al., 2007). The majority of these studies are associated with the fate of VOC emissions from petroleum industry in which VOCs emitted from various stages of crude oil processing including exploration, extraction, and production (Aklilu et al., 2018;DeLuchi, 1993;Helmig et al., 2014;Huang et al., 2018;Koss et al., 2017;Papailias and Mavroidis, 2018;Salih et al., 2018;Simpson et al., 2010;Villasenor et al., 2003;Wang et al., 2014;Warneke et al., 2014), storage (DeLuchi, 1993;Jackson, 2006;Khoramfar et al., 2018;Paulauskiene et al., 2009;Theophanides et al., 2007), transportation (de Vos et al., 2007;DeLuchi, 1993;Howard and Nikolas, 2001;Karbasian et al., 2017;Lee and Chang, 2014;Lee et al., 2013;Martens et al., 2001;Milazzo et al., 2017;Paulauskiene et al., 2008;Sani and Mohanty, 2009;Sani and Mohanty, 2008;Tamaddoni et al., 2014), refineries (Baltrėnas et al., 2011;Cetin et al., 2003;Lin and Lee, 2006;Lin et al., 2004;Liu et al., 2008;Pandya et al., 2006;Ragothaman and Anderson, 2017;Sonibare et al., 2007;Wei et al., 2014b;Wei et al., 2016;Zargar et al., 2013;Zhang Z. et al., 2017;Zhang et al., 2018), offshore (Afshar-Mohajer et al., 2019;Afshar-Mohajer et al., 2018;Bahreini et al., 2012;Han et al., 2007;Hanna and Drivas, 1993;Müller and Sedláčková, 2003;Saeed and Al-Mutairi, 2000;Saeed et al., 2013;Schädle et al., 2014;Tonacci et al., 2015;Uhler et al., 2010;Yagi et al., 2004;Yuan et al., 2014) and onshore activities (Almudhhi, 2016;Lawlor et al., 1997;Moyer et al., 1994;Müller and Sedláčková, 2003;Mustafa Salih et al., 2018;Soukup et al., 2007;Wang et al., 2015a;Wang et al., 2015b;Yang et al., 2007) as well as accidental spillages. ...
... However, only a few studies have focused on analysing the major mechanisms of CVEs and their influential parameters under different conditions such as water soluble fraction of HCs in crude oil contaminated soil (Saeed and Al-Mutairi, 2000;Saeed et al., 2013), ocean oil spillage (Afshar-Mohajer et al., 2018;Hanna and Drivas, 1993;Tonacci et al., 2015) and contaminated lands (Yang et al., 2007). The majority of these studies are associated with the fate of VOC emissions from petroleum industry in which VOCs emitted from various stages of crude oil processing including exploration, extraction, and production (Aklilu et al., 2018;DeLuchi, 1993;Helmig et al., 2014;Huang et al., 2018;Koss et al., 2017;Papailias and Mavroidis, 2018;Salih et al., 2018;Simpson et al., 2010;Villasenor et al., 2003;Wang et al., 2014;Warneke et al., 2014), storage (DeLuchi, 1993;Jackson, 2006;Khoramfar et al., 2018;Paulauskiene et al., 2009;Theophanides et al., 2007), transportation (de Vos et al., 2007;DeLuchi, 1993;Howard and Nikolas, 2001;Karbasian et al., 2017;Lee and Chang, 2014;Lee et al., 2013;Martens et al., 2001;Milazzo et al., 2017;Paulauskiene et al., 2008;Sani and Mohanty, 2009;Sani and Mohanty, 2008;Tamaddoni et al., 2014), refineries (Baltrėnas et al., 2011;Cetin et al., 2003;Lin and Lee, 2006;Lin et al., 2004;Liu et al., 2008;Pandya et al., 2006;Ragothaman and Anderson, 2017;Sonibare et al., 2007;Wei et al., 2014b;Wei et al., 2016;Zargar et al., 2013;Zhang Z. et al., 2017;Zhang et al., 2018), offshore (Afshar-Mohajer et al., 2019;Afshar-Mohajer et al., 2018;Bahreini et al., 2012;Han et al., 2007;Hanna and Drivas, 1993;Müller and Sedláčková, 2003;Saeed and Al-Mutairi, 2000;Saeed et al., 2013;Schädle et al., 2014;Tonacci et al., 2015;Uhler et al., 2010;Yagi et al., 2004;Yuan et al., 2014) and onshore activities (Almudhhi, 2016;Lawlor et al., 1997;Moyer et al., 1994;Müller and Sedláčková, 2003;Mustafa Salih et al., 2018;Soukup et al., 2007;Wang et al., 2015a;Wang et al., 2015b;Yang et al., 2007) as well as accidental spillages. In addition to the source-specific properties of CVEs (i.e. ...
Airborne Volatile organic compounds (VOCs) are known to have strong and adverse impacts on human health and the environment by contributing to the formation of tropospheric ozone. VOCs can escape during various stages of crude oil processing, from extraction to refinery, hence the crude oil industry is recognised as one of the major sources of VOC release into the environment. In the last few decades, volatile emissions from crude oil have been investigated either directly by means of laboratory and field-based analyses, or indirectly via emission inventories (EIs) which have been used to develop regulatory and controlling measures in the petroleum industry. There is a vast amount of scattered data in the literature for both regional emissions from crude oil processing and scientific measurements of VOC releases. This paper aims to provide a critical analysis of the overall scale of global emissions of VOCs from all stages of oil processing based on data reported in the literature. The volatile compounds, identified via EIs of the crude oil industry or through direct emissions from oil mass, are collected and analysed to present a global-scale evaluation of type, average concentration and detection frequency of the most prevalent VOCs. We provide a critical analysis on the total averages of VOCs and key pieces of evidence which highlights the necessity of implementing control measures to regulate crude oil volatile emissions (CVEs) in primary steps of extraction-to-refinery pathways of crude oil processing. We have identified knowledge gaps in this field which are of importance to control the release of VOCs from crude oil, independent of oil type, location, operating conditions and metrological parameters.
... This implies a possible increase in the total amount of aerosolized oily compounds when the slick is treated with dispersant. Laboratory comparisons between 0.5-mm-thick slicks of crude oil only and those with a dispersant to oil ratio (DOR) of 1:25 over the seawater surface in a breaking waves facility resulted in up to two orders of magnitude increase in the number concentration of b50 nm droplets (Afshar-Mohajer et al., 2018). ...
... In contrast, there was a considerable increase in the total number concentration and a decrease in the particle mode size of particles smaller than 380 nm. Therefore, dosimetry modeling of the airborne PM for understanding the region-specific deposition of inhaled particles focused on UFPs, which has shown the greatest sensitivity to the dispersant content of the slick (Afshar-Mohajer et al., 2018;Liyana-Arachchi et al., 2014;Ehrenhauser et al., 2014;Mustaffa et al., 2014;Zhang et al., 2016). Therefore, only the total particle mass concentrations and its size distributions over the particle diameters ranging from about 10 nm to 100 nm was considered in the PM dosimetry calculations (Table 1). ...
... . SI.1. Further details about the tank characteristics and configurations of the sampling instruments are explained and discussed byAfshar-Mohajer et al., 2018. ...
Airborne toxic compounds emitted from polluted seawater polluted after an oil spill raise health concerns when inhaled by humans or other species. Inhalation of these toxic compounds as volatile organic compounds (VOCs) or airborne fine particulate matter (PM) may cause serious pulmonary diseases, including lung cancer. Spraying chemical dispersants to enhance distribution of the crude oil into the water was employed extensively during the Deepwater Horizon spill. There is some evidence that dispersion of the crude oil decreased the emission rate of the VOCs but increased the emission rates of fine PM that may carry toxic compounds. In this study, the cancer risks and non-cancer hazards of the detected VOCs and particulates for spill-response workers were estimated with and without use of dispersant under action of breaking waves. A subchronic exposure scenario was modeled to address the inhalation health threat during initial phases of an oil spill response. A dosimetry model was used to estimate regional deposition of PM. Use of dispersant reduced benzene cancer risks from 57 to 37 excess lifetime cancer cases per million for 1 h of daily exposure that continues for 3 months. Adding dispersant resulted in emissions reductions of the lighter VOCs (up to 30% lower). However, hazard quotients (HQs) of the non-carcinogenic VOCs even after dispersant addition were above 1 meaning there are serious concerns about exposure to these VOCs. Inhalation of airborne particles emitted from the slick containing dispersant increased the total mass of deposited particles in upper respiratory regions compared to the slick of crude oil only. This study showed the application of dispersant onto the pollution slick increased the total mass burden to the human respiratory system about 10 times, an exploratory HQ analysis is presented to evaluate the potential health risk.
... The purpose of this study was to provide a technical proposal and a short economic analysis regarding CO2 capture technology in the oil refining industry. We referred to open sources that addressed the main parameters affecting the calculation of costs as well as direct emissions from the production process of refineries around the world [90][91][92][93][94][95][96][97][98][99][100][101][102][103][104]. The purpose of this study was to provide a technical proposal and a short economic analysis regarding CO 2 capture technology in the oil refining industry. ...
... The purpose of this study was to provide a technical proposal and a short economic analysis regarding CO 2 capture technology in the oil refining industry. We referred to open sources that addressed the main parameters affecting the calculation of costs as well as direct emissions from the production process of refineries around the world [90][91][92][93][94][95][96][97][98][99][100][101][102][103][104]. The CO 2 capture technologies found in the literature were divided into short-term and long-term technologies. ...
This study determines and presents the capital and operating costs imposed by the use of CO2 capture technologies in the refining and petrochemical sectors. Depending on the refining process and the CO2 capture method, CO2 emissions costs of EUR 30 to 40 per ton of CO2 can be avoided. Advanced low-temperature CO2 capture technologies for upgrading oxyfuel reformers may not provide any significant long-term and short-term benefits compared to conventional technologies. For this reason, an analysis was performed to estimate the CO2 reduction potential for the oil and gas industries using short- and long-term ST/MT technologies, was arriving at a reduction potential of about 0.5–1 Gt/yr. The low cost of CO2 reduction is a result of the good integration of CO2 capture into the oil production process. The results show that advanced gasoline fraction recovery with integrated CO2 capture can reduce the cost of producing petroleum products and reduce CO2 emissions, while partial CO2 capture has comparative advantages in some cases.
... More specifically, it is the bubble size distribution that controls gas transfer [4,5] and spray production as bubbles burst at the surface [6][7][8][9]. Bubbles also play a major role in industrial applications like oil and gas transportation from remote wells [10] or oil spill mitigations [11,12]. ...
... N (d, t) = Q −1/3 d −10/3 for d > d h (12) N (d, t) = Q We c 2 γ ρ −11/10 2/5 d −3/2 for d < d h (13) where Q is the volume of air injected to the breaking cascade per volume of water per second. In summary, when d 0 d h , large-scale inertial break-ups and small-scale capillary splitting events occur concurrently. ...
The bubble size distribution below a breaking wave is of paramount interest when quantifying mass exchanges between the atmosphere and oceans. Mass fluxes at the interface are driven by bubbles that are small compared with the Hinze scale dh, the critical size below which bubbles are stable, even though individually these are negligible in volume. Combining experimental and numerical approaches, we report a power-law scaling d−3/2 for the small bubble size distribution, for sufficiently large separation of scales between the injection size and the Hinze scale. From an analysis of individual bubble breakups, we show that small bubbles are generated by capillary effects, and that their breakup time scales as d3/2, which physically explains the sub-Hinze scaling observed.
... Researchers used a 6 × 0.3 × 0.6-m tank to simulate wave patterns colliding with oil slicks. To determine aerosol particle size distribution, tests were conducted measuring seawater with crude oil slicks, crude oil and dispersant mixtures, and dispersant only (Afshar-Mohajer et al., 2018). Results revealed that seawater mixed with crude oil only showed similar distribution of submicron particle sizes to that of seawater free of contaminants, but addition of dispersants mixed with crude oil to seawater decreased VOC concentration by two to three times while increasing the concentration of nanoparticles across all nano sizes measured (Afshar-Mohajer et al., 2018). ...
... To determine aerosol particle size distribution, tests were conducted measuring seawater with crude oil slicks, crude oil and dispersant mixtures, and dispersant only (Afshar-Mohajer et al., 2018). Results revealed that seawater mixed with crude oil only showed similar distribution of submicron particle sizes to that of seawater free of contaminants, but addition of dispersants mixed with crude oil to seawater decreased VOC concentration by two to three times while increasing the concentration of nanoparticles across all nano sizes measured (Afshar-Mohajer et al., 2018). The authors noted that reduction in water surface tension is responsible for the increased concentration of aerosolized particles, explaining why dispersant-oil mixtures are found to have highest concentration of particulate matter (PM). ...
Abstract The Gulf of Mexico Research Initiative (GoMRI) was established in 2010 with $500 million in funding provided by British Petroleum over a 10‐year period to support research on the impacts of the Deepwater Horizon oil spill and recovery. Contributions of the GoMRI program to date focused on human health are presented in more than 32 peer‐reviewed papers published between 2011 and May 2019. Primary findings from review of these papers are (i) the large quantity of dispersants used in the oil cleanup have been associated with human health concerns, including through obesogenicity, toxicity, and illnesses from aerosolization of the agents; (ii) oil contamination has been associated with potential for increases in harmful algal blooms and numbers of pathogenic Vibrio bacteria in oil‐impacted waters; and (iii) members of Gulf communities who are heavily reliant upon natural resources for their livelihoods were found to be vulnerable to high levels of life disruptions and institutional distrust. Positive correlations include a finding that a high level of community attachment was beneficial for recovery. Actions taken to improve disaster response and reduce stress‐associated health effects could lessen negative impacts of similar disasters in the future. Furthermore, GoMRI has supported annual conferences beginning in 2013 at which informative human health‐related presentations have been made. Based on this review, it is recommended that the Oil Pollution Act of 1990 be updated to include enhanced funding for oil spill impacts to human health.
... A recent study which investigated the effects of wave energy and slick properties on the temporal evolution of emissions, measured aerosol size distribution, total particle-bound aromatic hydrocarbons (pPHA), and volatile organic compounds (VOCs) in three different experimental scenarios in a tank: seawater plus slicks of (1) Louisiana Light Sweet crude oil (a surrogate of the M252 oil released in the DWH oil spill), (2) crude oil-dispersant mixture, and (3) dispersant only. (Afshar-Mohajera et al., 2018) The dispersant used in these experiments was Corexit 9500A (Nalco Environmental Solutions, Inc.), the primary dispersant used in the DWH oil spill clean-up. The investigators reported that the total particulate concentration from the oil-dispersant mixture was 1-2 orders of magnitude higher than those of crude oil alone across the entire nano-scale range, though not in the micron range. ...
... The authors hypothesized this decrease in VOC may be due to suppression of organic diffusion across interfaces coated with the dispersant or because of an increase in the dissolution rate of organic compounds into the water column, thus reducing the partitioning to the atmosphere. (Afshar-Mohajera et al., 2018) The results of this study are of relevance to human populations involved in oil-spill cleanup scenarios in which dispersant application is used, and the DWH oil spill cleanup relied heavily on the Corexit 9500A dispersant. ...
Introduction:
The Deepwater Horizon (DWH) oil spill was the largest marine oil spill in U.S. history, involving the response of tens of thousands clean-up workers. Over 8500 United States Coast Guard personnel were deployed in response to the spill. Little is understood about the acute neurological effects of oil spill clean-up-related exposures. Given the large number of people involved in large oil spill clean-ups, study of these effects is warranted.
Methods:
We utilized exposure, health, and lifestyle data from a post-deployment survey administered to Coast Guard responders to the DWH oil spill. Crude oil exposure was assessed via self-reported inhalation and skin contact metrics, categorized by frequency of self-reported exposure to crude oil during deployment (never, rarely, sometimes, most/all of the time). Combined exposure to crude oil and oil dispersant was also evaluated. Adjusted log binomial regressions were used to calculate prevalence ratios (PRs) and 95% confidence intervals (CI), investigating the associations between oil spill exposures and neurological symptoms during deployment. Stratified analyses investigated potential effect modification by sex, exhaust fume exposure, personal protective equipment (PPE) use, and deployment duration and timing.
Results:
Increasing frequency of crude oil exposure via inhalation was associated with increased likelihood of headaches (PRmost/all vs. never = 1.80), lightheadedness (PRmost/all vs. never = 3.36), difficulty concentrating (PRmost/all vs. never = 1.72), numbness/tingling sensation (PRmost/all vs. never = 3.32), blurred vision (PRmost/all vs. never = 2.87), and memory loss/confusion (PRmost/all vs. never = 2.03), with significant tests for trend. Similar results were found for crude oil exposure via skin contact. Exposure to both oil and oil dispersants yielded associations that were appreciably greater in magnitude than for oil alone for all neurological symptoms. Sensitivity analyses excluding responders in the highest environmental heat categories and responders with relevant pre-existing conditions indicated robustness of these results. Stratified analyses indicated possible effect modification by sex, PPE use, and heat exposure.
Conclusions:
This study provides evidence of a cross sectional association between crude oil exposures and acute neurological symptoms in a sample of U.S. Coast Guard responders. Additionally, it suggests that exposure to both crude oil and oil dispersant may result in stronger associations and that heat may interact synergistically with oil exposures resulting in more acute neurological symptoms. Future investigations are needed to confirm these findings.
... One chemical ingredient of Corexit (2-butoxyethanol), according to the New Jersey Department of Health (2008), may be a carcinogen and should be treated as such. Research has documented the dangers of inhalation/ingestion of ultrafine airborne particulate matter (caused by the mixture of dispersants with crude oil) consisting of volatile organic compounds (VOCs) such as benzene (a carcinogen), polycyclic aromatic hydrocarbons (PACs), and other crude petroleum hydrocarbons (Afshar-Mohajer et al. 2018, Baurick 2018Goldstein, Osofsky and Lichtveld 2011;Sawyer 2011). The toxicity of such mixed compounds increases by between 10 -100 times, and they are drawn deeper into the lungs, where they continue to break down and absorb into the cells (Afshar-Mohajer et al. 2018;Baurick 2018, Singleton et al. 2016, potentially resulting in lung cancer (Sawyer 2011). ...
... Research has documented the dangers of inhalation/ingestion of ultrafine airborne particulate matter (caused by the mixture of dispersants with crude oil) consisting of volatile organic compounds (VOCs) such as benzene (a carcinogen), polycyclic aromatic hydrocarbons (PACs), and other crude petroleum hydrocarbons (Afshar-Mohajer et al. 2018, Baurick 2018Goldstein, Osofsky and Lichtveld 2011;Sawyer 2011). The toxicity of such mixed compounds increases by between 10 -100 times, and they are drawn deeper into the lungs, where they continue to break down and absorb into the cells (Afshar-Mohajer et al. 2018;Baurick 2018, Singleton et al. 2016, potentially resulting in lung cancer (Sawyer 2011). Similarly, skin cancer may result from repeated or prolonged exposure to such compounds (Sawyer 2011). ...
A rapid ethnographic assessment conducted in 2016 engaged fishermen, their communities, and fisheries along the Gulf of Mexico coast five years after the Deepwater Horizon blowout of 2010. Interviews with fishermen in Florida, Alabama, Mississippi, and Louisiana elicited information on individual and collective experiences with the disaster, including their perceptions of the lingering consequences of BP’s “out-of-sight, out-of-mind” strategy—their attempts to sink the oil with dispersants. Focusing on clean-up efforts, this article reports that no community visited was completely spared the effects of the spill, although its impacts were clearly uneven based on proximity to the spill and political economic responses to it. Findings indicate that coastal fishing communities in Louisiana appear to have suffered the most in terms of enduring adverse impacts and have yet to fully recover.
... The aim is to establish quantitative relationships of the main cavity, breaking criteria and energy dissipation with respect to the fluid properties and initial conditions by reproducing experimental waves through 2-D DNS. A series of breaking-wave experiments were conducted in a 6 m long, 0.3 m wide and 0.6 m high wave flume, with the aim of investigating the breaking processes and the dispersion of oil spills by breaking waves Afshar-Mohajer et al. 2018;Wei et al. 2018). The breaking waves are initialized by driving a piston-type wavemaker over a constant water depth d. ...
The present study focuses on two-dimensional direct numerical simulations of shallow-water breaking waves, specifically those generated by a wave plate at constant water depths. The primary objective is to quantitatively analyse the dynamics, kinematics and energy dissipation associated with wave breaking. The numerical results exhibit good agreement with experimental data in terms of free-surface profiles during wave breaking. A parametric study was conducted to examine the influence of various wave properties and initial conditions on breaking characteristics. According to research on the Bond number ( Bo , the ratio of gravitational to surface tension forces), an increased surface tension leads to the formation of more prominent parasitic capillaries at the forwards face of the wave profile and a thicker plunging jet, which causes a delayed breaking time and is tightly correlated with the main cavity size. A close relationship between wave statistics and the initial conditions of the wave plate is discovered, allowing for the classification of breaker types based on the ratio of wave height to water depth, H/d . Moreover, an analysis based on inertial scaling arguments reveals that the energy dissipation rate due to breaking can be linked to the local geometry of the breaking crest , and exhibits a threshold behaviour, where the energy dissipation approaches zero at a critical value of . An empirical scaling of the breaking parameter is proposed as , where represents the breaking threshold and is a power law determined through the best fit to the numerical results.
... On the one hand, Cordes et al.,Johnston et al., and Zakari et al., investigated the need for in-depth statistical analysis to study the adverse effects of VOCs on the environment and the human ecosystem[54][55][56]. On the other hand, Finkel and Hays mentioned that living close to large oil and gas fields and industries, which have a direct link with VOC emissions, has a major effect on people"s health[57].Fundamental research is also needed to close the gaps in VOC monitoring technology to create effective, inexpensive, portable certified instruments to improve the monitoring, capture, and utilization of VOCs.Since the main objective of the study was to assess the possibility of increasing energy efficiency and reducing VOC and CO2 emissions based on Russian and international experience, the conclusions drawn do not contain assessments of any scientific, political, or legislative decisions. Different Russian and international regulatory documents set different limits on the amount of volatile organic compounds that can be emitted. ...
The impact of emissions from the fuel and energy sectors adversely affects the environment on the economies of countries. One of these pollutants is volatile organic compounds (VOCs), which contribute to the formation of tropospheric ozone. Emissions of hydrocarbon formation in the form of VOCs occur in four stages of the fuel and energy industry sector: (1) production, (2) processing, (3) transportation, and (4) storage. The oil and gas industry ranks among the top polluting industries in terms of VOC emissions. Research on the negative impact of VOCs, as well as CO2 emissions from the consequences of the extraction, processing, transport, and storage of oil and gas on the ecosystem of the planet and the population, has begun to be studied by science recently. Typically, these studies were conducted using laboratory and field analyses, as well as using data on anthropogenic emissions in the development of regulatory documents and requirements governing the control of VOC and CO2 emissions in the oil and gas industry. This paper presents a critical analysis of the literature on research on the negative effects of VOC emissions on the ecosystem and human health because of such factors as production, processing, transportation, and storage of hydrocarbons. This analysis shows the global magnitude of VOC emissions. Data from human‐made emissions from the oil and gas industry and direct emissions from transportation and energy processing were used to figure out how VOCs affect the environment around the world and how far they spread. In conclusion, this study found patterns of VOC emissions that show how important it is to control VOCs during the production, processing, transportation, and storage of oil and gas, as well as how important it is to create a single research base on emissions for each industry sector and on sources of greenhouse gas absorption.
... A series of breaking wave experiments have been conducted in the Department of Mechanical Engineering of Johns Hopkins University in a 6m long, 0.3m wide, and 0.6m high wave flume with the aim to study the dispersion of oil spills by breaking waves [22,23]. The breaking waves are initialized by driving a piston-type wavemaker over a uniform water depth d=0.25m. ...
... Laboratory studies have demonstrated that physical processes such as breaking waves and raindrops (or drops splashed from breaking waves) can produce oily aerosols when these drops impact surface oil slicks treated with dispersants (Afshar-Mohajer et al., 2018Murphy et al., 2015). Field measurements of oily aerosols in the vicinity of a dispersant-treated oil are needed, since these oily aerosols can pose a human health risk (Afshar-Mohajer et al., 2019) and may pose similar risks to air-breathing wildlife, such as birds, sea turtles, and marine mammals. ...
Characterizing the nature and effects of oil released into the marine environment is very challenging. It is generally recognized that “environmentally relevant” conditions for exposure involve a range of temporal and spatial conditions, a range of exposure pathways (e.g., dissolved, emulsions, sorbed onto particulates matter), and a multitude of organisms, populations, and ecosystems. Various exposure methodologies have been used to study the effects of oil on aquatic organisms, and uniform protocols and exposure methods have been developed for the purposes of regulatory toxicological assessments. Ultimately, all exposure methods have drawbacks, it is impossible to totally mimic field conditions, and the choice of exposure methodology depends on the specific regulatory, toxicological, or other research questions to be addressed. The aim of this paper is to provide a concise review of the state of knowledge to identify gaps in that knowledge and summarize challenges for the future.
... Plastic aquatic debris are both a point-source for some UV-filter pollution (e.g., oxybenzone, benzotriazole, benzophenone-8) as well as a concentrator of petrochemical UV-filters; UV-filters adhere to the plastic particle surface, increasing the concentration of UV-filter-exposure if consumed by aquatic wildlife (Rani et al., 2017;Hahladakis et al., 2018;O'Donovan et al., 2020;Na et al., 2021;Santa-Viera et al., 2021;Cui et al., 2022). Aerosol/atmospheric distribution and deposition is a newly recognized source, coming directly from the use of aerosol sunscreens, volatilization from waste-water facilities, and through aerosolization of wave action along the shoreline (Wan et al., 2015;Shoeib et al., 2016;Afshar-Mohajer et al., 2018;Pegoraro et al., 2020;Du et al., 2022). ...
In 2019, sands in nearby runoff streams from public beach showers were sampled on three islands in the State of Hawaii and tested for over 18 different petrochemical UV filters. Beach sands that are directly in the plume discharge of beach showers on three of the islands of Hawaii (Maui, Oahu, Hawai’i) were found to be contaminated with a wide array of petrochemical-based UV-filters that are found in sunscreens. Sands from beach showers across all three islands had a mean concentration of 5,619 ng/g of oxybenzone with the highest concentration of 34,518 ng/g of oxybenzone at a beach shower in the Waikiki area of Honolulu. Octocrylene was detected at a majority of the beach shower locations, with a mean concentration of 296.3 ng/g across 13 sampling sites with the highest concentration of 1,075 ng/g at the beach shower in Waikiki. Avobenzone, octinoxate, 4-methylbenzylidene camphor and benzophenone-2 were detected, as well as breakdown products of oxybenzone, including benzophenone-1, 2,2'-dihydroxy-4-methoxybenzophenone, and 4-hydroxybenzophenone. Dioxybenzone (DHMB) presented the highest concentration in water (75.4 ng/mL), whereas octocrylene was detected in all water samples. Some of these same target analytes were detected in water samples on coral reefs that are adjacent to the beach showers. Risk assessments for both sand and water samples at a majority of the sampling sites had a Risk Quotient >1, indicating that these chemicals could pose a serious threat to beach zones and coral reef habitats. There are almost a dozen mitigation options that could be employed to quickly reduce contaminant loads associated with discharges from these beach showers, like those currently being employed (post-study sampling and analysis) in the State of Hawaii, including banning the use of sunscreens using petrochemical-based UV filters or educating tourists before they arrive on the beach.
... and light scattering particles, production from bursting bubbles (Lewis & Schwartz, 2004;Wang et al., 2017); as well as to better understand the generation and composition of aerosols associated with chemical agents used in oil-spill mitigation (Afshar-Mohajer et al., 2018;Feng et al., 2014;Sampath et al., 2019). ...
Gas bubbles bursting at the sea surface produce drops, which contribute to marine aerosols. The contamination or enrichment of water by surface‐active agents, of biological or anthropogenic origin, has long been recognized as affecting the bubble bursting processes and the spray composition. However, despite an improved understanding of the physics of a single bursting event, a quantitative understanding of the role of the physico‐chemical conditions on assemblies of bursting bubbles remains elusive. We present experiments on the drop production by millimetric, collective bursting bubbles, under varying surfactant concentration and bubble density. We demonstrate that the production of supermicron droplets (with radius larger than 35 μm) is non‐monotonic as the surfactant concentration increases. The bursting efficiency is optimal for short‐lived, sparsely distributed and non‐coalescing bubbles. We identify the combined role of contamination on the surface bubble arrangement and the modification of the jet drop production process in the bursting efficiency.
... Quantifying interfacial tension, viscosity, density, and the effects of wave energy on droplet size distribution bridges small-scale physical processes for slick breakup and large-scale oceanic transport processes. This tank system was used by Afshar-Mohajer et al. (2018 to generate aerosolized volatile organic compounds and particulate matter that were then measured to provide data for a health risk assessment for oil spill response workers. Cui et al. (2020) used subsurface droplets generated by this tank system for corroboration of test results from a deepwater wave tank system designed to study oil dispersion. ...
The Gulf of Mexico Research Initiative (GoMRI) program funded research for 10 years following the Deepwater Horizon incident to address five themes, one of which was technology developments for improved response, mitigation, detection, characterization, and remediation associated with oil spills and gas releases. This paper features a sampling of such developments or advancements, most of which cite studies funded by GoMRI, but we also include several developments that occurred outside this program. We provide descriptions of new techniques or the novel application or enhancement of existing techniques related to studies on the evolution of the subsurface oil plume, the collection of data on ocean currents to support oil transport modeling, and oil spill modeling. We also feature developments related to the interactions of oil with particulate matter and microbial organisms, sampling for studies and analysis of biogeochemical processes related to oil fate, human health risks from inhalation of oil spill chemicals, impacts on marine life, and alternative dispersant technologies to Corexit®. Many of the techniques featured here have contributed to complementary or subsequent research and have applications beyond oil spill research that can contribute to a wide range of scientific endeavors.
... Wave tank measurements (C. Li et al., 2017;Afshar-Mohajer et al., 2018) provide a comprehensive database on the spatial and temporal size distribution of subsurface droplets as a function of wave energy, dispersant concentration, oil viscosity, depth, and time after wave breaking. The measured time evolution of turbulence in the tank has been used for correlating the evolution of droplet size distribution to their subsurface transport. ...
Physical transport processes such as the circulation and mixing of waters largely determine the spatial distribution of materials in the ocean. They also establish the physical environment within which biogeochemical and other processes transform materials, including naturally occurring nutrients and human-made contaminants that may sustain or harm the region’s living resources. Thus, understanding and modeling the transport and distribution of materials provides a crucial substrate for determining the effects of biological, geological, and chemical processes. The wide range of scales in which these physical processes operate includes microscale droplets and bubbles; small-scale turbulence in buoyant plumes and the near-surface “mixed” layer; submesoscale fronts, convergent and divergent flows, and small eddies; larger mesoscale quasi-geostrophic eddies; and the overall large-scale circulation of the Gulf of Mexico and its interaction with the Atlantic Ocean and the Caribbean Sea; along with air-sea interaction on longer timescales. The circulation and mixing processes that operate near the Gulf of Mexico coasts, where most human activities occur, are strongly affected by wind- and river-induced currents and are further modified by the area’s complex topography. Gulf of Mexico physical processes are also characterized by strong linkages between coastal/shelf and deeper offshore waters that determine connectivity to the basin’s interior. This physical connectivity influences the transport of materials among different coastal areas within the Gulf of Mexico and can extend to adjacent basins. Major advances enabled by the Gulf of Mexico Research Initiative in the observation, understanding, and modeling of all of these aspects of the Gulf’s physical environment are summarized in this article, and key priorities for future work are also identified.
... We focus this discussion vertically, from the air-sea interface into the water column. Breaking waves and bubble bursting can create aerosolized oil droplets, which may be a hazard to oil spill responders (Afshar-Mohajer et al. [224]; Liyana-Arachchi et al. [225]), so there is work to be done to improve our understanding of surface oil processes. ...
Following the 2010 Deepwater Horizon accident of a massive blow-out in the Gulf of Mexico, scientists from government, industry, and academia collaborated to advance oil spill modeling and share best practices in model algorithms, parameterizations, and application protocols. This synergy was greatly enhanced by research funded under the Gulf of Mexico Research Initiative (GoMRI), a 10-year enterprise that allowed unprecedented collection of observations and data products, novel experiments, and international collaborations that focused on the Gulf of Mexico, but resulted in the generation of scientific findings and tools of broader value. Operational oil spill modeling greatly benefited from research during the GoMRI decade. This paper provides a comprehensive synthesis of the related scientific advances, remaining challenges, and future outlook. Two main modeling components are discussed: Ocean circulation and oil spill models, to provide details on all attributes that contribute to the success and limitations of the integrated oil spill forecasts. These forecasts are discussed in tandem with uncertainty factors and methods to mitigate them. The paper focuses on operational aspects of oil spill modeling and forecasting, including examples of international operational center practices, observational needs, communication protocols, and promising new methodologies.
... It was also observed that a number of oil droplets were shot up into the air with the water splash up (Fig. 7f at x = 8.2 m) and fell back on to the water surface later due to the gravity (Fig. 7f, g). The aerosolization of oil droplets has been a topic of importance in oi spill studies [1,39]. However, transport in the air is not the focus of the current investigation. ...
Oil dispersion under a deep-water plunging breaker of height 0.15 m was studied by coupling the Lagrangian particle tracking code (NEMO3D) with the population balance model (VDROP). The wave hydrodynamics obtained in Part I (Cui et al. in Environ Fluid Mech 2020 (in press)) was used as input. It was observed that droplet inertia and major forces on droplets significantly impacted the transport of oil droplets under wave conditions, and neglecting it caused less entrainment into the water column and horizontal spread of oil plume. For droplets less than 400 microns, the droplet size distribution (DSD) tended to follow a power-law distribution with an exponent close to − 2.3, which was consistent with earlier experimental observations by Delvigne and Sweeney (Oil Chem Pollut 4(4):281-310, 1988). The distribution of large size droplets evolved with time and showed agreement with a power-law distribution having an exponent of − 9.7 about 20 s after the passage of the wave train. Reducing the interfacial tension enhanced droplets breakup and increased the exponent of power-law distribution to − 6.1 for droplets smaller than 400 microns. It was also found that neglecting the vertical gradient of eddy diffusivity led to the accumulation of oil droplets in low eddy diffusivity regions at the bottom part of the wave breaker. The investigation herein could be used to obtain design values for breakers that could be used in oil spill models to predict the oil droplet size distribution.
... The airborne particle size is inversely associated with the final size of the bubbles right before bursting on the water surface (Spiel, 1997). Furthermore, there is evidence that the number concentration of airborne PM smaller than 400 nm (i.e., number of particles per volume of air) only increases substantially after addition of a dispersant, thus a more careful consideration of particle size is warranted (Afshar-Mohajer et al., 2018;Liyana-Arachchi et al., 2014;Sampath et al., 2019;Sellegri et al., 2006). ...
Inhalation of PM2.5, particles with an aerodynamic diameter <2.5 μm, from sea spray after crude oil spills could present serious health concerns. The addition of dispersants to effectively spread the crude oil throughout the water column has been practiced in recent years. Here, we investigated the possibility of an increase in the toxic content of fine PM after adding dispersant. A laboratory setup consisted of a vertical tank filled with seawater, 31.5 L airspace for aerosol sampling, and a bubble generating nozzle that aerosolized the oily droplets. Four different cases were studied: no slick, 0.5-mm-thick slick of pure crude oil (MC252 surrogate), dispersant (Corexit 9500A) mixed with crude oil at dispersant to oil ratio (DOR) 1:25, and DOR 1:100. The resulting airborne droplets were sampled for gravimetric and chemical analyses through development of a gas chromatography and mass spectrometry technique. Also, PM2.5 particles were size-fractioned into 13 size bins covering <60 nm to 12.1 μm using a low-pressure cascade impactor.
The highest PM2.5 concentration (20.83 ± 5.21 μg/m³) was released from a slick of DOR 1:25, 8.83× greater than the case with pure crude oil. The average ratio of crude oil content from the slick of DOR 1:25 to the case with pure crude oil was 2.37 (1.83 vs 0.77 μg/m³) that decreased to 1.17 (0.90 vs 0.77 μg/m³) at DOR 1:100. For particles <220 nm, the resultant crude oil concentrations were 0.64 and 0.29 μg/m³ at DOR 1:25 and 1:100, both higher than 0.11 μg/m³ from the slick of pure crude oil.
... The stage of crude oil transfer from the fields of production to the refineries and consumption centers is difficult due to passage in rugged routes (Yue et al. 2018). Typically, crude oil is transported through domestic refineries and export terminals via pipelines and crude oil shipping vessels (Afshar-Mohajer et al. 2018). The accumulation of economic hydrocarbon materials economy in the reservoir is subject to several factors. ...
In this study, ZnO nanoparticles were modified with rice bran. Synthesis and production of
ZnO nano-particles is highly important due to the use of rice bran. In addition, XRD and
SEM analyses were used to ensure the production quality of the nano-particles. The images clearly showed surface uniformity of the synthesized organic ZnO nano-particles. Afterward, the modified nano-particles were injected into crude oil in different weight percentages according to their properties (heavy and light crude oil). The injection was done at a temperature range of 30–150 �C with operating pressures varying from 10 bar to 300 bar. The adhesion force created between heavy or light crude oil molecules and organic ZnO nanoparticles was modified with rice bran. Furthermore, an increase in the operating temperature increased the thermal conductivity of oil samples from 0.21 to 2.54 W/m �C for the light crude oil sample and 1.56–6.3 W/m �C for the heavy crude oil sample. The results showed that the percentage of the asphaltene precipitation decreased with the increased API of the crude oil. In addition, the percentage of asphaltene precipitation for nano-light and heavy crude oil was considerably better than the simple light and heavy crude oil samples, respectively. The nano-particles improved the crude oil recovery from reservoirs. The results indicate that the probability of asphaltene precipitation in the case of light crude oil nanoparticles is less than the simple light crude oil by 28.3%. This is 8.1% for the heavy crude oil compared to the simple heavy crude oil.
... The most abundant VOCs identified in the atmosphere over the seawater covered with the crude oil slicks were hexane, cyclohexane, and heptane. Upon oil spillage, marine aerosols are ejected into the atmosphere by breaking waves (Afshar-Mohajer et al. 2018). This process includes several steps; firstly, there is splashing into water resulting in the generation of bubbles and their subsequent rise to the surface and bursting to produce aerosolized droplets. ...
An oil spill is the release of liquid petroleum hydrocarbons (PHs) into the environment, especially the terrestrial (land) and aquatic ecosystems, due to human activities, and is a form of pollution. When the oil is spilled, it normally spreads out and moves in and on the surfaces of spilled sites while undergoing several physico-chemical changes. These processes are collectively termed as “weathering” or “oil weathering processes” (OWP) and determine the “fate of the oil.” The speed and relative importance of the processes depend on several factors such as (i) the quantity of spill, (ii) the oil’s initial physical (surface tension, specific gravity, and viscosity) and chemical characteristics, (iii) existing environmental conditions, and (iv) whether the oil remains at or runs off from the spilled site. In land-oil spill, there is a high-level possibility of leaching of spilled oil into groundwater or entering waterways (i.e., rivers and streams) as runoff and to return the soil to productive use as quickly as possible. Various hydrocarbon fractions of spilled oil in marine environments are selectively subjected to evaporation (very volatile fractions), oxidation, and dissolution into the water table (dissolved oxygen combines with oil to produce water-soluble compounds), spreading, accumulation as persistent residues, and biodegradation by microorganisms. In certain cases, the contaminated area can be flooded, wherein oil floats or moves to water surface since some of the fractions of crude oil are lighter (i.e., propane and benzene) than water. The present chapter emphasizes the fate of total petroleum hydrocarbons (TPHs) in various environments immediately after the spill.
... At the particle scale, the aerosolized oil droplets may exhibit various non-spherical shapes and instantaneous deformations, which can be different from those for the natural sea spray droplets. The difference may become more significant if dispersants are applied for oil spill remediation, which can reduce the oil surface tension to enhance droplet breakup [29,30]. These effects are not included in the current LES considering that the coarse grid resolution used in a typical LES of the MABL flow cannot provide sufficient information for directly determining the detailed droplet shapes. ...
In this study, a hybrid large-eddy simulation (LES) model is developed and applied to simulate the transport of oil droplet aerosols in wind over progressive water waves. The LES model employs a hybrid spectral and finite difference method for simulating the wind turbulence and a bounded finite-volume method for modeling the oil aerosol transport. Using a wave-following coordinate system and computational grid, the LES model captures the turbulent flow and oil aerosol fields in the region adjacent to the unsteady wave surface. A flat-surface case with prescribed roughness (representing a pure wind-sea) and a wavy-surface case with regular plane progressive 100 m long waves (representing long-crest long-wavelength ocean swells) are considered to illustrate the capability of the LES model and study the effects of long progressive waves on the transport of oil droplet aerosols with four different droplet diameters. The simulation results and statistical analysis reveal enhanced suspension of oil droplets in wind turbulence due to strong disturbance from the long progressive waves. The spatial distribution of the aerosol concentration also exhibits considerable streamwise variations that correlate with the phase of the long progressive waves.
... They confirm that bursting of 550-to 870-μm bubbles causes emission of organic particles and shows that premixing the oil with dispersant increases their total mass. Moreover, our preliminary tests near breaking waves impinging on oil and dispersant-contaminated seawater (Afshar-Mohajer et al., 2018), indicate that many of the particles aerosolized from the seawater when the oil slick is premixed with dispersant are small as 10 nm. ...
Bubble bursting is a primary source of marine aerosols, yet little is known about particle emissions due to the bubble bursting in slicks containing oil‐dispersant mixtures. In this study, bubbles with mode sizes of 86 μm (denoted as small), 178 μm (medium), and 595 μm (large) are injected into a seawater column covered by slicks of crude oil, pure dispersant, and dispersant premixed with oil at a ratio of 1:25. The aerosol size distributions are monitored in the 0.5‐ to 20‐μm and 10‐ to 380‐nm ranges both in clean and ambient air environments. In ambient air, a tenfold increase in submicron particle concentration occurs when large bubbles burst on slicks of 500‐μm dispersant premixed with oil at a ratio of 1:25 oil or 50‐μm pure dispersant. Yet, in multiple tests performed at different ambient particle concentrations, the elevated size distributions persistently maintain the same shape as that of the ambient air. In contrast, smaller bubbles and tests not involving dispersants do not cause such an increase. Nanodroplets are also generated by large bubbles in particle‐free air, but their concentrations are much lower. All plumes generate micron‐sized aerosols, but trends vary. For the same contaminant, the microdroplet concentration decreases with increasing slick thickness. Particularly striking is a reduction of 2 orders of magnitude in the microdroplet concentration when medium and small bubbles burst on 500‐μm crude oil slicks. Chemical analysis of air and particulates collected from filters sampling the particles confirms the presence of airborne oil above the slicks.
... The stage of crude oil transfer from the fields of production to the refineries and consumption centers is difficult due to passage in rugged routes (Yue et al. 2018). Typically, crude oil is transported through domestic refineries and export terminals via pipelines and crude oil shipping vessels (Afshar-Mohajer et al. 2018). The accumulation of economic hydrocarbon materials economy in the reservoir is subject to several factors. ...
In this study, ZnO nanoparticles were modified with rice bran. Synthesis and production of ZnO nano-particles is highly important due to the use of rice bran. In addition, XRD and SEM analyses were used to ensure the production quality of the nano-particles. The images clearly showed surface uniformity of the synthesized organic ZnO nano-particles. Afterward, the modified nano-particles were injected into crude oil in different weight percentages according to their properties (heavy and light crude oil). The injection was done at a temperature range of 30–150 °C with operating pressures varying from 10 bar to 300 bar. The adhesion force created between heavy or light crude oil molecules and organic ZnO nano-particles was modified with rice bran. Furthermore, an increase in the operating temperature increased the thermal conductivity of oil samples from 0.21 to 2.54 W/m °C for the light crude oil sample and 1.56–6.3 W/m °C for the heavy crude oil sample. The results showed that the percentage of the asphaltene precipitation decreased with the increased API of the crude oil. In addition, the percentage of asphaltene precipitation for nano-light and heavy crude oil was considerably better than the simple light and heavy crude oil samples, respectively. The nano-particles improved the crude oil recovery from reservoirs. The results indicate that the probability of asphaltene precipitation in the case of light crude oil nano-particles is less than the simple light crude oil by 28.3%. This is 8.1% for the heavy crude oil compared to the simple heavy crude oil.
The widespread use of acrylonitrile (Acyrlonitrile) and crude C4 across industries has significantly boosted global manufacturing of these energy-intensive petrochemicals. A life cycle assessment was employed to evaluate the environmental impact of Acyrlonitrile and C4 production, aiming to promote sustainability in the petrochemical supply chain. Modeling integrated refinery-petrochemical plant operations in Türkiye revealed that Acyrlonitrile production emitted 7.46 kg CO2eq./kg, while C4 production emitted 1.62 kg CO2eq./kg. The Acyrlonitrile production was found to be more environmentally polluting, especially in terms of acidification potential, photochemical smog potential and eutrophication potential with 4.5 kg SO2eq., 3.88 kg C2H4eq. and 2.39 kg PO4eq. per kg Acyrlonitrile respectively. Waste disposal, natural gas use, propane and nitrogen emission have been the major hotspots of Acyrlonitrile production, while natural gas use and lubricant oil for C4. On average, the production stage emerged as the primary hotspot, for Acyrlonitrile production contributing 58% to overall impacts. The results of water footprint identified 3.13 L per kg Acyrlonitrile and 0.99 L per kg C4 production, with aromatics and ethylene plants being the key contributors. Adoption of energy efficiency measures and circular economy principles is recommended to mitigate environmental impacts. This study sheds light on the resource-intensive petrochemical supply chain, offering valuable insights into environmental impact assessment in this sector.
Input of polycyclic aromatic hydrocarbon (PAH) contamination in marine ecosystems occurs over several orders of magnitude and microbial degradation is a relevant and arguably crucial attenuation process. However, the remediation of low-dosage PAH contaminations through biodegradation remains largely unstudied. In the presented thesis, the knowledge gap surrounding PAH-degradation activity under different contaminant loads was addressed with a combination of numerical modelling and laboratory experiments covering questions from the dynamics of biochemical pathways to the overall response of environmental systems. In the first published study presented in this thesis, a process-based numerical model was developed. Biomass growth and naphthalene degradation were simulated for Cycloclasticus spp. batch cultures receiving repeated low-dosage naphthalene pulses compared to the conventionally used one-time high-dosage Vogel et al., 2023a. The results showed that pulsing frequency and dosage concentration impacted the degradation efficiency in the simulated experiments considerably. In consequence, dissolution kinetics dictated biodegradation and biomass growth, making the final biomass concentration of PAH-degrading bacteria alone not a sufficient indicator for the quantification of active biodegradation. Furthermore, a one-time input of a high-naphthalene dose was degraded faster than repeated low dosages, implying that repeated low-dosage input could lead to PAH accumulation in exposed pristine environments. Thus, the interactions of coupled low-concentration pollutant degradation and microbial growth processes were elucidated and the results may have important implications for future bioremediation management of diffuse oil contamination in the marine environment. For risk assessment and bioremediation monitoring, knowledge of in situ degradation rates is imperative. The ratio of mRNA to DNA of functional genes, the professed transcript-to-gene ratio, could be a cultivation-independent, measurement to obtain per-cell degradation rates - potentially even in a high-throughput manner. If successful, such a measure would provide a method for quantifying in situ PAH-degradation rates. The second and third studies aimed, therefore, to understand expression of functional genes under various PAH loads, which might help to monitor and predict bioremediation efficiency in the future. It was, however, unknown if the transcription of PAH-degradation biomarker genes could serve as an indicator of active PAH degradation. Using the model PAH degrader Cycloclasticus pugetii strain PS-1, substrate-independent expression of three key functional marker genes was found during the degradation of naphthalene, phenanthrene, a combination of both, and no-PAH controls at high concentrations (i.e., 200 mg L-1) using qPCR Vogel et al., 2023b. In subsequent RNA-sequencing experiments with high and low naphthalene dosages (i.e., 100 and 30 mg L-1) genetic redundancy was detected as 15 genes encoding for enzymes involved in the initial step of PAH degradation were highly transcribed. Remarkably, some of these were transcribed during active naphthalene degradation, while others were expressed in naphthalene-starvation treatments. Additionally, some genes - including the three functional marker genes from Vogel et al., 2023b - were expressed substrate-independently, regardless of available naphthalene Vogel et al., 2024. Hence, two distinct enzymatic systems for the naphthalene-degradation pathway were proposed: one where the encoding genes were transcribed substrate-independently resulting in "background" PAH degradation, and a second system where the encoding genes were transcribed in response to the PAH enabling a "rapid response" following naphthalene exposure. This hypothesized genetic flexibility might allow highly specialized PAH degraders like Cycloclasticus spp. to adapt to changing PAH dosages (i.e., concentrations) in a need-based manner. Ultimately, the results imply that the transcription of PAH-marker genes does not necessarily correspond with PAH-degradation activity, and (meta-)transcription data should always be evaluated with caution. In summary, this work has greatly expanded our understanding of the dependence between PAH degradation (activity) and gene expression in marine environments. The presented thesis highlights how an interdisciplinary approach which includes numerical modelling and wet-lab-based studies can close knowledge gaps that are difficult to investigate with more classical experiments. The results show that the so-far-overlooked parameters of PAH dosage and frequency can highly influence biodegradation on multiple levels and, thereby, the fate of contaminants within marine environments.
To improve the adsorption and reusability of polypropylene (PP) fiber membranes, the organically modified saponite (Sap@P(St‐co‐MMA)) was prepared by solution polymerization. Furthermore, PP‐based nanocomposite fiber membranes with strong oil adsorption, thermal stability, and reusability were prepared via melt‐blown technology. The increased specific surface area of PP‐based nanocomposite fiber membranes (PP‐1.5%) provided more active sites for the oil adsorption. Simultaneous rheology and Fourier transform infrared measurements tests showed that Sap@P(St‐co‐MMA) enhanced the crystallinity of PP matrix, promoted the regular arrangement of molecules, and improved the intermolecular interaction force, which was beneficial for the oil adsorption. The adsorption of PP‐1.5% (1.5 wt% addition of Sap@P(St‐co‐MMA)) fiber membrane for xylene and kerosene reached a maximum of 15.84 and 22.84 g g ⁻¹ , respectively. In the treatment of coal tar wastewater, the removal rate of oil can reach 62.9%, and the removal rate can still reach 51.17% after five cycles of experiments. In summary, PP‐1.5% fiber membrane does not produce secondary pollution to the environment, and is a kind of oil removal material with good application prospect.
Highlights
PP‐based nanocomposites fiber membrane with strong oil adsorption was prepared.
Organically modified saponite had strong heterogenous nucleation for PP matrix.
Sap@P(St‐co‐MMA) increased the specific surface area of PP‐based fiber membrane.
Organically modified saponite (Sap@P(St-co-MMA)) additives were prepared by solution polymerization with saponite as matrix and with styrene and methyl methacrylate as monomer, poly (propylene) (PP)/Sap@P(St-co-MMA) nanocomposites fiber membranes are prepared by melt-blown spinning. PP fiber membranes with improved hydrophobicity, thermal stability, crystallinity, and adsorption properties were prepared. The specific surface area of PP fiber membranes (PP-1.5%) with the addition of 1.5% additive is 129.11 m ² g − 1 , which provided more active sites for the adsorption of oil substances from wastewater. Simultaneous rheological measurement and FTIR analysis showed that Sap@P(St-co-MMA) could improve the crystallinity of PP matrix, so that PP molecules were regularly arranged to improve the intermolecular interaction force, which was favorable for the adsorption of oil substances. The adsorption of PP-1.5% fiber membrane conformed to a pseudo-second order kinetic model, which could be expressed by the Langmuir isothermal model, and the oil removal of 51% was still achieved after 5 cycles of recycling with a maximum removal of 65%. Accordingly, PP-1.5% fiber membrane can efficiently remove the oil substances in wastewater without secondary pollution to the environment, and it is a kind of oil removal material with good application prospect.
Petroleum hydrocarbons, including alkanes ranging from C10 to C32, have been recognized as priority organic water contaminants with a toxic impact on ecosystems. Therefore, the removal of these contaminants is of utmost importance to protect humans, plants and animals. In this work, biochar derived from the dead leaves of the widely-distributed seagrass Halodule uninervis (SGC) was prepared through biomass pyrolysis at 800°C and characterized using SEM, FTIR, TGA and surface area analysis. The prepared SGC was investigated for adsorptive removal of total petroleum hydrocarbons (TPHs) and individual alkane hydrocarbons (C10 to C32) from water contaminated with crude oil. The SGC displayed good removal efficiency, adsorption capacity and recyclability toward these hydrocarbons. Using the SGC, 98.8% of the TPHs were removed within 300 minutes with an adsorption capacity of 23.5 mg/g. The adsorption results were tested with the most commonly used isotherm and kinetics models. The hydrocarbon adsorption data for the SGC fit the Langmuir and Freundlich isotherms, which indicates non-uniformity of the adsorbent and a predominance of multilayer adsorption of the hydrocarbons onto the prepared SGC adsorbent. The performance and reusability of the prepared SGC adsorbent were promising, losing only 22% of its hydrocarbon removal efficiency after the 3rd cycle.
A series of GOMRI-sponsored experimental and computational studies have discovered, elucidated and quantified the impact of small-scale processes on the dispersion, transport and weathering of crude oil slicks and subsurface plumes. Physical interfacial phenomena occurring at micron-scales include the formation of particle-stabilized emulsions, penetration of particles into oil droplets, formation of compound water-containing oil droplets during plume breakup, and the mechanisms affecting the breakup of oil into micro-droplet by tip streaming resulting from the drastic reduction in interfacial tension upon introduction of dispersant. Efforts aimed at development targeted delivery of surfactants have introduced solvent-free halloysite nanotubes that can be filled with surfactants, and preferentially released at oil-water interface. Buoyant surfactant-based gels, which enhance their encounter rates with oil slicks and adhere to weathered oil have also been developed. Studies of oil-bacteria interactions during early phases of biodegradation and shown how the bacteria, some highly active, attach to the oil-water interfaces and form complex films. Clay-decorated droplets sequester these bacteria and promote the propagation of these biofilm. Long extracellular polymeric substance (EPS) streamers generated by these biofilms form connected networks involving multiple droplets and debris, as well as increase the drag on the oil droplets. At 0.01–10 m scales, the generation of subsurface and airborne crude oil droplets by breaking waves, subsurface plumes and raindrop impact have been quantified. For waves, premixing the oil with dispersant reduces the droplets sizes to micron- and submicron-scales, and changes the slope of their size distribution. Without dispersant, the droplet diameters can be predicted based on the turbulence scales. With dispersant, the droplets are much smaller than the turbulence scales owing to the abovementioned tip-streaming. Aerosolization of oil is caused both by the initial splash and by subsequent bubble bursting, as entrained bubbles rise to the surface. Introduction of dispersant increases the airborne nano-droplet concentration by orders of magnitude, raising health questions. Dispersant injection also reduces the size of droplets in subsurface plumes, affecting the subsequent dispersion of these plume by currents and turbulence. Advancements have also been made in modeling of dissolution of oil in plumes, as well as in applications of Large Eddy Simulations (LES) to model plumes containing oil droplets and gas bubbles. The new multiscale framework, which accounts for the droplet size distribution and mass diffusion, can simulate the near- and far-fields of plumes, and predict the effect of vertical mixing promoted by turbulence on the transport of dispersed oil.
We study bubble break-up in homogeneous and isotropic turbulence by direct numerical simulations of the two-phase incompressible Navier-Stokes equations. We create the turbulence by forcing in physical space and introduce the bubble once a statistically stationary state is reached. We perform a large ensemble of simulations to investigate the effect of the Weber number (the ratio of turbulent and surface tension forces) on bubble break-up dynamics and statistics, including the child bubble size distribution, and discuss the numerical requirements to obtain results independent of grid size. We characterize the critical Weber number below which no break-up occurs and the associated Hinze scale. At Weber number close to stable conditions (initial bubble sizes), we observe binary and tertiary break-ups, leading to bubbles mostly between and, a signature of a production process local in scale. For large Weber numbers (3d_h$]]>), we observe the creation of a wide range of bubble radii, with numerous child bubbles between and, an order of magnitude smaller than the parent bubble. The separation of scales between the parent and child bubble is a signature of a production process non-local in scale. The formation mechanism of these sub-Hinze scale bubbles relates to rapid large deformation and successive break-ups: the first break-up in a sequence leaves highly deformed bubbles which will break again, without recovering a spherical shape and creating an array of much smaller bubbles. We discuss the application of this scenario to the production of sub-Hinze bubbles under breaking waves. © The Author(s), 2021. Published by Cambridge University Press.
In our daily life, the demand for liquid petroleum products is increasing day by day. Crude oil-derived hydrocarbons, the largest group of environmental pollutants found worldwide, pollute our environments severely. Oil or hydrocarbons cause drastic impacts on living organisms. The many reports about their toxicity emphasize the ultimate need to remove them from marine and terrestrial environments. For cleaning up pollution by these hydrocarbons, bioremediation seems to be the most acceptable and economically justified method. Bioremediation is considered one of the most sustainable cleanup techniques, but its potential has not been fully expressed in the field because it operates too slowly to meet the immediate demands of a given location. The process of bioremediation is carried out by various microorganisms. Therefore, in this review, we present information about methods of oil degradation by such microorganisms as bacteria, fungi, algae, and actinobacteria. These microbes can help degrade oil or hydrocarbons. This review presents the unique characteristics of oil-degrading microbes. In addition, it is a starting point for wider debate about the limitations and possible improvements of currently employed hydrocarbon bioremediation strategies.
Direct contact with toxicants in crude oil during embryogenesis causes cardiovascular defects, but the effects of exposure to airborne volatile organic compounds released from spilled oil are not well understood. The effects of crude oil-derived airborne toxicants on peripheral blood flow were examined in Gulf killifish (Fundulus grandis) since this model completes embryogenesis in the air. Particle image velocimetry was used to measure in vivo blood flow in intersegmental arteries of control and oil-exposed embryos. Significant effects in oil-exposed embryos included increased pulse rate, reduced mean blood flow speed and volumetric flow rate, and decreased pulsatility, demonstrating that normal-appearing oil-exposed embryos retain underlying cardiovascular defects. Further, hematocrit moderately increased in oil-exposed embryos. This study highlights the potential for fine-scale physiological measurement techniques to better understand the sub-lethal effects of oil exposure and demonstrates the efficacy of Gulf killifish as a unique teleost model for aerial toxicant exposure studies.
Link to full text: https://authors.elsevier.com/c/1biwFB8ccoKj9
To confirm the higher-availability and lower-resistance superiority of a proposed seawater/seawater cascade-scrubbing solution meeting the emission control area (ECA) requirements under harsh high-sulfur and low-alkalinity conditions, desulfurization experiments for the exhaust gas of a 162-kW marine diesel engine were compared between the cascade-scrubbing model and currently used once-through, open-loop solution. With the once-through seawater to scrub SO2 levels of 1,000–2,860 mg/Nm3 (equal to about 1.8%–5% fuel-sulfur content), the desulfurization efficiency of the once-through system increased with the liquid-gas ratio and seawater alkalinity and decreased with SO2 concentration. At the harsh SO2 concentration of 2,860 mg/Nm3 where the once-through scrubbing thoroughly failed to meet the ECA’s requirements, an additional liquid-gas ratio increase above 8 L/Nm3 was confirmed to be infeasible because of the potential for liquid flooding. In contrast, with a total liquid-gas ratio ≥9 L/Nm3 (typically liquid-gas ratios of 7 and 2 L/Nm3 in the main and auxiliary scrubbing sections, respectively), the cascade-scrubbing model easily met the ECA’s desulfurization requirements under harsh high-sulfur and low-alkalinity conditions, along with its lower packing pressure-drop levels allowing for a further liquid-gas ratio increase. Aside from the above superiority compared with the once-through open-loop solution, the achievement of high-efficiency seawater desulfurization in this work suggests that the proposed seawater/seawater cascade-scrubbing solution should be more economical in comparison to the current closed-loop solution and hybrid system, which both necessitate costly NaOH usage.
In 2010 the Gulf Coast experienced the largest oil spill affecting U.S. waters in history. Evaporating crude oil and dispersant chemicals can cause major health problems. This paper examines the impact of the Deepwater Horizon oil spill on air quality and infant health outcomes. Using U.S. Environmental Protection Agency (EPA) AirData, vital statistics data from National Center for Health Statistics (NCHS), and a difference-in-difference methodology, we find that the oil spill of 2010 increased concentrations of PM2.5, NO2, SO2, and CO in affected coastal counties, increased incidence of low birth weight (<2500 g) and premature born infants (<37 weeks of gestation). Heterogeneity effects reveal more pronounced adverse infant health outcomes for black, Hispanic, less educated, unmarried, and younger mothers. Results are robust to a wide range of controls and robustness checks.
Sea spray is one of the largest natural aerosol sources and plays an important role in the Earth’s radiative budget. These particles are inherently hygroscopic, that is, they take-up moisture from the air, which affects the extent to which they interact with solar radiation. We demonstrate that the hygroscopic growth of inorganic sea salt is 8–15% lower than pure sodium chloride, most likely due to the presence of hydrates. We observe an increase in hygroscopic growth with decreasing particle size (for particle diameters <150 nm) that is independent of the particle generation method. We vary the hygroscopic growth of the inorganic sea salt within a general circulation model and show that a reduced hygroscopicity leads to a reduction in aerosol-radiation interactions, manifested by a latitudinal-dependent reduction of the aerosol optical depth by up to 15%, while cloud-related parameters are unaffected. We propose that a value of κs=1.1 (at RH=90%) is used to represent the hygroscopicity of inorganic sea salt particles in numerical models.
The high-speed impact of a droplet on a bulk fluid at high Weber number (We) is not well understood but is relevant to the production of marine aerosol by raindrop impact on the sea surface. These splashes produce a subsurface cavity and a crown which closes into a bubble canopy, but a floating layer of immiscible oil, such as a crude oil slick, alters the splash dynamics. The effects of oil layer fluid properties and thickness, droplet size and impact speed are examined by high-speed visualization. Oil layer rupture and crown behaviour are classified by dimensional scaling. The subsurface cavity volume for impact on thick layers is shown to depend on the Reynolds number (Re), although canopy formation at high Re introduces a competing We effect since rapid canopy closure is found to retard cavity expansion. Time-resolved kinematic measurements show that thin crude oil slicks similarly alter crown closure and cavity growth. The size and spatial distributions of airborne droplets are examined using high-speed holographic microscopy. The droplets have a bimodal distribution with peaks at 50 and 225 μm and are clustered by size at different elevation angles. Small droplets (50 μm) are ejected primarily at shallow angles, indicating production by splashing within the first 100 μs and by breakup of microligaments. Larger droplets (225 μm) are found at steeper elevation angles, indicating later production by capillary instability acting on large ligaments protruding upward from the crown. Intermittent droplet release while the ligaments grow and sweep upward is thought to contribute to the size-dependent spatial ordering. Greater numbers of small droplets are produced at high elevation angles when a crude oil layer is present, indicating satellite droplet formation from ligament breakup. A crude oil layer also increases the target fluid Ohnesorge number, leading to creation of an intact ejecta sheet, which then ruptures to form aerosolized oil droplets.
The baffled flask test (BFT) has been proposed by United States Environmental Protection Agency to be adopted as the official standard protocol for testing dispersant effectiveness. The mixing energy in the baffled flask is investigated in this paper. Particle image velocimetry (PIV) was used to measure the water velocity in the flask placed at an orbital shaker that was rotated at seven rotation speeds: 100, 125, 150, 160, 170, 200, and 250 rpm. Two dimensional velocity fields in large and small vertical cross sections of the flask for each rotation speed were obtained. The one-dimensional (1D) energy spectra indicates the existence of inertial subrange. The estimated average energy dissipation rates were in the range 7.65×10-3 to 4 W/kg for rotation speeds of Ω=100-250 rpm, of which it is larger than the one estimated by prior studies using single-point velocity measurement techniques for Ω=100 and 200 rpm. Factors such as instruments used, velocity components measured, and different analysis methods could contribute to the discrepancies in the results. The Kolmogorov scale estimated in this study for all seven rotation speeds approached the size of oil droplets observed at sea, which is 50-400 μm. The average energy dissipation rate, ε and Kolmogorov microscale, η, in the flasks were correlated to the rotation speed, and it was found that
ε
¯
=
9.0
×
10
-
5
Exp (0.043Ω) with R2 = 0.97 and
η
¯
=
1
,
463
Exp (-0.015Ω) with R2 = 0.98.
The Bedford Institute of Oceanography in Nova Scotia used a wave tank to simulate the propagation and breaking of deep water waves. A technique for generating breaking waves at the same location in the tank was used to obtain a spilling and a plunging breaker. Plunging breaking waves had heights of 0.25 m. The regular waves, on the average, had an energy dissipation rate of 5 × l0 -4 watt/kg deep in the water column, indicating that breaking plays an important role in the dispersion of oil at sea. This is an abstract of a paper presented at the International Oil Spill Conference 2008 Proceedings (Savannah, GA 5/4-8/2008).
Potential of mean force (PMF) calculations and molecular dynamics (MD) simulations were performed to investigate the properties of oil n-alkanes [i.e., n-pentadecane (C15), n-icosane (C20) and n-triacontane (C30)], as well as several surfactant species [i.e., the standard anionic surfactant sodium dodecyl sulfate (SDS), and three model dispersants similar to the Tween and Span species present in Corexit 9500A] at air/salt water interfaces. This study was motivated by the 2010 Deepwater Horizon (DWH) oil spill, and our simulation results show that, from the thermodynamic point of view, the n-alkanes and the model dispersants have a strong preference to remain at the air/salt water interface, as indicated by the presence of deep free energy minima at these interfaces. The free energy minimum of these n-alkanes becomes deeper as their chain length increases, and as the concentration of surfactant species at the interface increases. The n-alkanes tend to adopt a flat orientation and form aggregates at the bare air/salt water interface. When this interface is coated with surfactants, the n-alkanes tend to adopt more tilted orientations with respect to the vector normal to the interface. These simulation results are consistent with the experimental findings reported in the accompanying paper [Ehrenhauser et al., Environ. Sci.: Processes Impacts 2013, in press, (DOI: 10.1039/c3em00390f)]. The fact that these long-chain n-alkanes show a strong thermodynamic preference to remain at the air/salt water interfaces, especially if these interfaces are coated with surfactants, makes these species very likely to adsorb at the surface of bubbles or droplets and be ejected to the atmosphere by sea surface processes such as whitecaps (breaking waves) and bubble bursting. Finally, the experimental finding that more oil hydrocarbons are ejected when Corexit 9500A is present in the system is consistent with the deeper free energy minima observed for the n-alkanes at the air/salt water interface at increasing concentrations of surfactant species.
We investigated the surfactant dioctyl sodium sulfosuccinate (DOSS) and its delivery system Corexit 9500A, used to disperse oil released during the Gulf of Mexico spill during the summer of 2010. DOSS is an organic sulfonic acid salt that acts as a synthetic detergent and disrupts the interfacial tension between the salt water and crude oil phases. The disruption reaches a maximum at or above the critical micelle concentration (CMC). The CMC for the surfactant was determined to be 0.17% solution in deionized water at a pH of 7.2 and a temperature of 21.1 °C (70°F). The CMC is lower in salt water, at 0.125% solution. This has been identified as a “salting out” effect (Somasundaran, 2006). The CMC of DOSS in both saline and deionized water occurred at lower-percent solutions at higher temperatures. The surface tension versus concentration plots can be modeled using a power equation, with correlation coefficients consistently over 0.94. Surface tension versus concentration plots are scalable to fit the desired temperature by the function f(x) = (1/1+Xα), where α =T1/T2. Tests measured the stability of the DOSS micelles when exposed to a continuous UVA radiation. This photodegradation is directly related to the duration of exposure.
The availability of reliable, accurate and precise monitoring methods for toxic volatile organic compounds (VOCs) is a primary need for state and local agencies addressing daily monitoring requirements related to odor complaints, fugitive emissions, and trend monitoring. The canister-based monitoring method for VOCs is a viable and widely used approach that is based on research and evaluation performed over the past several years. The activity has involved the testing of sample stability of VOCs in canisters and the design of time-integrative samplers. The development of procedures for analysis of samples in canisters, including the procedure for VOC preconcentration from whole air, the treatment of water vapor in the sample, and the selection of an appropriate analytical finish has been accomplished. The canister-based method was initially summarized in the EPA Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air as Method TO-14. Modifications and refinements are being added to Method TO-14 in order to obtain a Statement of Work for the Superfund Contract Laboratory Program for Air. The paper discusses the developments leading to the current status of the canister-based method and provides a critique of the method using results obtained in EPA monitoring networks. (Copyright (c) 1991 - Air and Waste Management Association.)
The quantification of three-dimensional (3D) flow structures and particle dynamics is crucial for unveiling complex interactions in turbulent flows. This review summarizes recent advances in volumetric particle detection and 3D flow velocimetry involving holography. We introduce the fundamental principle of holography and discuss the debilitating depth-of-focus problem, along with methods that have been implemented to circumvent it. The focus of this review is on recent advances in the development of in-line digital holography in general, and digital holographic microscopy in particular. A mathematical background for the numerical reconstruction of digital holograms is followed by a summary of recently introduced 3D particle tracking and velocity measurement techniques. The review concludes with sample applications, including 3D velocity measurements that fully resolve the flow in the inner part of a turbulent boundary layer, the diffusion of oil droplets in high–Reynolds number turbulence, and predator-p...
Three sorbents were compared in order to determine their potential for oil spill cleanup. Polypropylene nonwoven web, rice hull, and bagasse with two different particle sizes were evaluated in terms of oil sorption capacities and oil recovery efficiencies. Polypropylene can sorb almost 7 to 9 times its weight from different oils. Bagasse, 18 to 45 mesh size, follows polypropylene as the second sorbent in oil spill cleanup. Bagasse, 14 to 18 mesh size, and rice hull have comparable oil sorption capacities, which are lower than those of the two former sorbents. It was found that oil viscosity plays an important role in oil sorption by sorbents. All adsorbents used in this work could remove the oil from the surface of the water preferentially.
The fate of deepwater releases of gas and oil mixtures is initially determined by solubility and volatility of individual hydrocarbon species; these attributes determine partitioning between air and water. Quantifying this partitioning is necessary to constrain simulations of gas and oil transport, to predict marine bioavailability of different fractions of the gas-oil mixture, and to develop a comprehensive picture of the fate of leaked hydrocarbons in the marine environment. Analysis of airborne atmospheric data shows massive amounts (∼258,000 kg/day) of hydrocarbons evaporating promptly from the Deepwater Horizon spill; these data collected during two research flights constrain air-water partitioning, thus bioavailability and fate, of the leaked fluid. This analysis quantifies the fraction of surfacing hydrocarbons that dissolves in the water column (∼33% by mass), the fraction that does not dissolve, and the fraction that evaporates promptly after surfacing (∼14% by mass). We do not quantify the leaked fraction lacking a surface expression; therefore, calculation of atmospheric mass fluxes provides a lower limit to the total hydrocarbon leak rate of 32,600 to 47,700 barrels of fluid per day, depending on reservoir fluid composition information. This study demonstrates a new approach for rapid-response airborne assessment of future oil spills.
During the Deepwater Horizon (DWH) oil spill, a wide range of gas and aerosol species were measured from an aircraft around, downwind, and away from the DWH site. Additional hydrocarbon measurements were made from ships in the vicinity. Aerosol particles of respirable sizes were on occasions a significant air quality issue for populated areas along the Gulf Coast. Yields of organic aerosol particles and emission factors for other atmospheric pollutants were derived for the sources from the spill, recovery, and cleanup efforts. Evaporation and subsequent secondary chemistry produced organic particulate matter with a mass yield of 8 ± 4% of the oil mixture reaching the water surface. Approximately 4% by mass of oil burned on the surface was emitted as soot particles. These yields can be used to estimate the effects on air quality for similar events as well as for this spill at other times without these data. Whereas emission of soot from burning surface oil was large during the episodic burns, the mass flux of secondary organic aerosol to the atmosphere was substantially larger overall. We use a regional air quality model to show that some observed enhancements in organic aerosol concentration along the Gulf Coast were likely due to the DWH spill. In the presence of evaporating hydrocarbons from the oil, NO(x) emissions from the recovery and cleanup operations produced ozone.
Nanomaterials are engineered structures with at least one dimension of 100 nanometers or less. These materials are increasingly
being used for commercial purposes such as fillers, opacifiers, catalysts, semiconductors, cosmetics, microelectronics, and
drug carriers. Materials in this size range may approach the length scale at which some specific physical or chemical interactions
with their environment can occur. As a result, their properties differ substantially from those bulk materials of the same
composition, allowing them to perform exceptional feats of conductivity, reactivity, and optical sensitivity. Possible undesirable
results of these capabilities are harmful interactions with biological systems and the environment, with the potential to
generate toxicity. The establishment of principles and test procedures to ensure safe manufacture and use of nanomaterials
in the marketplace is urgently required and achievable.
Better understanding of particle–particle and particle–fluid interactions requires accurate 3D measurements of particle distributions and motions. We introduce the application of in-line digital holographic microscopy as a viable tool for measuring distributions of dense micrometer ( 3.2 μm ) and submicrometer ( 0.75 μm ) particles in a liquid solution with large depths of 1 – 10 mm . By recording a magnified hologram, we obtain a depth of field of ∼ 1000 times the object diameter and a reduced depth of focus of approximately 10 particle diameters, both representing substantial improvements compared to a conventional microscope and in-line holography. Quantitative information on depth of field, depth of focus, and axial resolution is provided. We demonstrate that digital holographic microscopy can resolve the locations of several thousand particles and can measure their motions and trajectories using cinematographic holography. A sample trajectory and detailed morphological information of a free-swimming copepod nauplius are presented.
The current knowledge in primary and secondary marine aerosol formation is reviewed. For primary marine aerosol source functions, recent source functions have demonstrated a significant flux of submicrometre particles down to radii of 20 nm. Moreover, the source functions derived from different techniques up to 10 microm have come within a factor of two of each other. For secondary marine aerosol formation, recent advances have identified iodine oxides and isoprene oxidation products, in addition to sulphuric acid, as contributing to formation and growth, although the exact roles remains to be determined. While a multistep process seems to be required, isoprene oxidation products are more likely to participate in growth and sulphuric acid is more likely to participate in nucleation. Iodine oxides are likely to participate in both nucleation and growth.
The wreckage of the oil tanker Prestige in November 2002 produced heavy contamination off the coast of Galicia, Spain.
To evaluate the prevalence of respiratory symptoms in local fishermen more than 1 year after having participated in clean-up work.
Questionnaires including qualitative and quantitative information about clean-up activities and respiratory symptoms were distributed among associates of 38 fishermen's cooperatives. Both postal and telephone follow-up was performed. The association between participation in clean-up work and respiratory symptoms was evaluated using multiple logistic regression analyses, adjusted for sex, age, and smoking status.
Between January 2004 and February 2005, data were obtained from 6,780 fishermen (response rate, 76%). Sixty-three percent had participated in clean-up operations. Lower respiratory tract symptoms (LRTS) were more prevalent in clean-up workers: odds ratio (OR), 1.73; 95% confidence interval (CI), 1.54-1.94. This association was consistent for men and women, for different fishermen's cooperatives, and for different types of respiratory symptoms, and remained after excluding those who reported anxiety or believed that the oil spill had affected their health (OR, 1.57; 95% CI, 1.37-1.80). The risk of LRTS increased with the number of exposed days, exposed hours per day, and number of activities (linear trend, P < 0.0001). The excess risk of LRTS decreased when more time had elapsed since last exposure: OR, 2.33, 1.69, and 1.24 for less than 14 months, 14-20 months, and more than 20 months, respectively.
Participation in clean-up work of oil spills may result in prolonged respiratory symptoms that last 1 to 2 years after exposure.
This laboratory experimental study investigates the temporal evolution of the size distribution of subsurface oil droplets generated as breaking waves entrain oil slicks. The measurements are performed for varying wave energy, as well as large variations in oil viscosity and oil-water interfacial tension, the latter achieved by premixing the oil with dispersant. In situ measurements using digital inline holography at two magnifications is applied for measuring the droplet sizes, and Particle Image Velocimetry (PIV) for determining the temporal evolution of turbulence after wave breaking. All early (2-10s) size distributions have two distinct size ranges with different slopes. For low dispersant to oil ratios (DOR), the transition between them could be predicted based on a turbulent Weber (We) number in the 2-4 range, suggesting that turbulence plays an important role. For smaller droplets, all the number size distributions have power of about -2.1, and for larger droplets, the power decreases well below -3. The measured steepening of the size distribution over time is predicted by a simple model involving buoyant rise and turbulence dispersion. Conversely, for DOR 1:100 and 1:25 oils, the diameter of slope transition decreases from ∼1mm to 46µm and 14µm respectively, much faster than the We-based prediction, and the size distribution steepens with increasing DOR. Furthermore, the concentration of micron-sized droplets of DOR 1:25 oil increase for the first ten minutes after entrainment. These phenomena are presumably caused by the observed formation and breakup oil micro-threads associated with tip streaming.
Significance
Environmental risks posed by deep-sea petroleum releases are difficult to predict and assess. We developed a physical model of the buoyant jet of petroleum liquid droplets and gas bubbles gushing into the deep sea, coupled with simulated liquid–gas equilibria and aqueous dissolution kinetics of petroleum compounds, for the 2010 Deepwater Horizon disaster. Simulation results are validated by comparisons with extensive observation data collected in the sea and atmosphere near the release site. Simulations predict that chemical dispersant, injected at the wellhead to mitigate environmental harm, increased the entrapment of volatile compounds in the deep sea and thereby improved air quality at the sea surface. Subsea dispersant injection thus lowered human health risks and accelerated response during the intervention.
The International Arctic Ocean Expedition 1991 (IAOE-91) provided a platform to study the occurrence and size distributions of ultrafine particles in the marine boundary layer (MBL) during Arctic summer and autumn. Measurements of both aerosol physics, and gas/particulate chemistry were taken aboard the Swedish icebreaker Oden. Three separate submicron aerosol modes were found: an ultrafine mode ( D p 100 nm). We evaluated correlations between ultrafine particle number concentrations and mean diameter with the entire measured physical, chemical, and meteorological data set. Multivariate statistical methods were then used to make these comparisons. A principal component (PC) analysis indicated that the observed variation in the data could be explained by the influence from several types of air masses. These were characterised by contributions from the open sea or sources from the surrounding continents and islands. A partial least square (PLS) regression of the ultrafine particle concentration was also used. These results implied that the ultrafine particles were produced above or in upper layers of the MBL and mixed downwards. There were also indications that the open sea acted as a source of the precursors for ultrafine particle production. No anti-correlation was found between the ultrafine and accumulation particle number concentrations, thus indicating that the sources were in separate air masses. DOI: 10.1034/j.1600-0889.1996.t01-1-00006.x
The mechanism of breaking of surface waves, particularly in deep water, is studied. It is proposed that a spilling breaker can be regarded as a turbulent gravity current riding down the forward slope of a wave, and can be treated using methods which have been successful in other contexts. The whitecap retains its identity because it is lighter than the water below, owing to the trapping of air bubbles, and information from laboratory experiments is used to estimate the density of the air-water mixture in different circumstances. A similarity solution is obtained under the assumptions that the flow is steady in time, and that the slope and density difference remain constant.
Ocean spray consists of small water droplets ejected from the ocean surface following surface breaking wave events. These drops get transported in the marine atmospheric boundary layer, in which they exchange momentum and heat with the atmosphere. Small spray droplets are transported over large distances and can remain in the atmosphere for several days, where they will scatter radiation; evaporate entirely, leaving behind sea salt; participate in the aerosol chemical cycle; and act as cloud condensation nuclei. Large droplets remain close to the ocean surface and affect the air-sea fluxes of momentum and enthalpy, thereby enhancing the intensity of tropical cyclones. This review summarizes recent progress and the emerging consensus about the number flux and implications of small sea spray droplets. I also summarize shortcomings in our understanding of the impact of large spray droplets on the meteorology of storm systems.
Bubble mediated processes such as gas transfer and bubble-burst aerosol
production have long been of geophysical interest. In contrast, the
bubble generation by bubble bursting remains unquantified. Based on a
series of laboratory experiments, evidence for bubble production by
bursting bubbles is presented as well as the bubble distribution
produced by this mechanism for salt and fresh water.
Influence of changes in the degree of saturation of the surface waters, with respect to the major atmospheric gases, on the aerosol productivity of an individual whitecap has now been inferred from results recently obtained using the University of Connecticut's Whitecap Simulation Tank IV. As the level of dissolved oxygen increased from 100% saturation to 130%, i.e., to a significant degree of supersaturation, the production of aerosol droplets by the whitecap generated by a standard laboratory breaking wave was found to increase by a factor of 2.4 in the case of submicron radius droplets, while the generation of larger droplets (r>2.5 mum) was observed to increase by at least a factor of 4.0. As a consequence of these findings, a multiplier, defined in terms of the degree of gas saturation, has been introduced as a term in the various sea surface aerosol generation models.
The relative contributions of jet and film drops from bursting bubbles to the sea-salt component of the marine aerosol is poorly understood. An analysis of the bubble and aerosol spectra produced by a laboratory model of a breaking wave or whitecap shows that film drops may play a much more important role than previously accorded. The model strongly suggests that most of the droplets smaller than 5-10 mum in diameter originate as film drops, derived from bubbles larger than 1 mm. The water-to-air flux of such droplets is adequate to account for the majority of maritime cloud condensation nuclei. The model also suggests that droplets larger than 20-25 mum originate as jet drops, derived from bubbles smaller than 1 mm. The model breaking wave produces an upwelling plume of bubbles whose concentration for all bubble sizes vastly exceeds the steady state or background bubble population observed at sea at depths greater than 1 m. Bubbles of up to 10 mm diameter were produced, and the bubble flux reached 200 cm-2 s-1. Whitecap bubble spectra presently unavailable, are therefore essential in making more accurate assessments of marine aerosol production.
Airborne particles are present throughout our environment. They come in many different forms, such as dusts, fumes, mists, smoke, smog, or fog. These aerosols affect visibility, climate, and our health and quanlity of life. This book covers the properties, behaviour, and measurement of aerosols. This is a basic textbook for people engaged in industrial hygiene, air pollution control, radiation protection, or environmental science who must, in the practice of their profession, measure, evaluate, or control airborne particles. It is written at a level suitable for professionals, graduate students, or advanced undergraduates. It assumes that the student has a good background in chemistry and physics and understands the concepts of calculus. Although not written for aerosol scientists, it will be useful to them in their experimental work and will serve as an introduction to the field for students starting such careers. Decisions on what topics to include were based on their relevance to the pratical application of aerosol science, which includes an understanding of the physical and chemical prinicples that underlie the behaviour of aerosols and the instruments used to measure them. (from preface)
The March 24, 1989, grounding of the Exxon Valdez on Bligh Reef in Prince William Sound, Alaska, was unprecedented in scale. So too was Exxon's response to the oil spill and the subsequent shoreline cleaning program, including the employment of more than 11,000 people, utilization of essentially the entire world supply of containment booms and skimmers, and an expenditure of more than two billion dollars. In the days immediately following the Valdez spill, Exxon mobilized a massive environmental assessment program. A large field and laboratory staff of experienced environmental professionals and internationally recognized experts was assembled that included intertidal ecologists, fishery biologists, marine and hydrocarbon chemists. This field program to measure spill impacts and recovery rates was initiated with the cooperation of state and federal agencies. Through the end of 1989, this program has resulted in well over 45,000 separate samples of water, sediment, and biota used to assess spill impacts. This paper provides initial observations and preliminary conclusions from several of the 1989 studies. These conclusions are based on factual, scientific data from studies designed to objectively measure the extent of the impacts from the spill. Data from these studies indicate that wildlife and habitats are recovering from the impacts of the spill and that commercial catches of herring and salmon in Prince William Sound are at record high levels. Ecosystem recovery from spill impacts is due to the combined efforts of the cleanup program as well as natural physical, chemical, and biological processes. From all indications this recovery process can be expected to continue.
Mass transfer processes of 2-ferrocenyl-2-propanol across a single-nitrobenzene-microdroplet/water interface were studied by laser trapping and microelectrochemical techniques. For mass transfer of the solute from water to the droplet, both fast and slow processes were observed. The mass transfer rate was governed by both adsorption of the compound on the droplet/water interface (slow) and diffusion in the water phase (fast). Kinetic parameters of the adsorption process per unit interfacial area of the droplet were determined, and the values were shown to depend on the droplet size. The observed droplet-size effect was originated from the intrinsic properties of a microdroplet. The role of adsorption of the solute on a micrometer-sized spherical liquid/liquid interface in the mass transfer processes is discussed.
A model is proposed for mass transfer of gases across surface-active films and into an aqueous phase. The interfacial region (1) obeys local equilibrium conditions, (2) has a capacity for the dissolved gases greater than the solubility in water, and (3) has a diffusion coefficient three orders of magnitude less than for that in water. The model is solved for and compared with three different experiments: the transient diffusion through monomolecular films into quiescent liquids studied by Plevan and Quinn (1966), the gas absorption through surfactant films into falling liquid films investigated by Emmert and Pigford (1954), and the frequency response of concentration pulses in surfactant films reported by Whitaker and Pigford (1966). The model consistently describes these experiments previously explained by three different models that either ignored the capacitance of the film or assumed local non-equilibrium.
Over the last two decades, the use of chemical dispersants as a countermeasure to oil spills at sea has become accepted worldwide. The recent development of more efficient and less toxic dispersants has renewed interest for basic studies on dispersant improvement and on the fate of dispersed oil in seawater. This work reports interfacial tensions and the effectiveness in oil dispersion of many synthetic, commercially available surfactants when used alone and in various blends. The results are discussed in terms of the local structure of the oil-water interface. The maximum efficiency is reached when the surfactant molecules have a structure compatibility and can form stable arrangements at the interface. An improved knowledge of interfacial phenomena responsible for the oil dispersion helps in formulating better dispersants by guiding a judicious combination of surfactants in appropriate proportions.
Over the past decade, the formation and growth of nanometer-size atmospheric aerosol particles have been observed at a number of sites around the world. Measurements of particle formation have been performed on different platforms (ground, ships, aircraft) and over different time periods (campaign or continuous-type measurements). The development during the 1990s of new instruments to measure nanoparticle size distributions and several gases that participate in nucleation have enabled these new discoveries. Measurements during nucleation episodes of evolving size distributions down to 3 nm can be used to calculate the apparent source rate of 3-nm particles and the particle growth rate. We have collected existing data from the literature and data banks (campaigns and continuous measurements), representing more than 100 individual investigations. We conclude that the formation rate of 3-nm particles is often in the range 0.01-10 cm-3 s-1 in the boundary layer. However, in urban areas formation rates are often higher than this (up to 100 cm-3 s-1), and rates as high as 104-10 5 cm-3 s-1 have been observed in coastal areas and industrial plumes. Typical particle growth rates are in the range 1-20 nm h-1 in mid-latitudes depending on the temperature and the availability of condensable vapours. Over polar areas the growth rate can be as low as 0.1 nm h-1. Because nucleation can lead to a significant increase in the number concentration of cloud condensation nuclei, global climate models will require reliable models for nucleation.
Sediment chemistry studies, undertaken as part of the long-term assessment of the Bahı́a las Minas (Panamá) oil spill, showed the unexpected persistence of the full range of aromatic hydrocarbon residues of the spilled crude oil in anoxic muds of coastal mangroves. Mangrove muds served as long-term reservoirs for chronic contamination of contiguous coastal communities for over 5 years. One result of the repeated history of oil pollution incidents along this coast was an increased proportion of dead mangrove (Rhizophora mangle) roots in sediment cores which was related to contaminant loading and was detectable for at least 20 years after major oil spills. We suggest that this is the minimum time-scale that is to be expected for the loss of toxicity of oil trapped in muddy coastal habitats impacted by catastrophic oil spills.
The aerodynamic particle sizer (APS) model 3321 (TSI, Inc., St. Paul, MN) aims to resolve issues identified with an earlier APS, model 3320. These issues include discrepancies between concentrations measured in summing and in correlated modes, and the creation of “anomalous”, large particles caused by recirculation within the detection region. In the present work, the number concentration of a laboratory aerosol was measured with the APS 3321 to be statistically the same in summing mode and in correlated mode for all particles except those in bin 1, . Further, anomalous large particles were not measured with the APS 3321. The counting efficiency of the APS 3321 was lower than that for the APS 3320 and ranged from 40% to 60% for particles from 0.8 to , respectively. Thus, concentrations reported by the APS 3321 were lower than those measured by the impactor. However, because counting efficiencies were roughly constant with particle size and anomalous particles were absent, the shape of the size distribution was similar to that obtained using the impactor.
Oil spilled at sea often forms oil droplets in stormy conditions. This paper examines possible mechanisms which generate the oil droplets. When droplet Reynolds numbers are large, the dynamic pressure force of turbulent flows is the cause of droplet breakup. Using dimensional analysis, Hinze (1955, A.I.Ch.E. Journal 1, 289–295) obtained a formula for the maximum size of oil droplets that can survive the pressure force. When droplet Reynolds numbers are small, however, viscous shear associated with small turbulent eddies is the cause of breakup. For the shear mechanism, we obtain estimates of droplet size as a function of energy dissipation rate, the ratio of oil-to-water viscosity and the surface tension coefficient.The two formulae are applied to oil spills in the ocean. At dissipation rates expected in breaking waves, the pressure force is the dominant breakup mechanism and can generate oil droplets with radii of hundreds of microns. However, when chemical dispersants are used to treat an oil slick and significantly reduce the oil-water interfacial tension, viscous shear is the dominant breakup mechanism and oil droplets with radii of tens of microns can be generated. Viscous shear is also the mechanism for disintegrating water-in-oil emulsions and the size of a typical emulsion blob is estimated to be tens of millimeters.
Laboratory investigations were performed on the natural dispersion of surface and submerged oil. Surface oil broke up into droplets and penetrated the water column due to the effect of breaking waves. Submerged oil parcels (submerged spill) broke up into droplets due to turbulence in the ambient water. The experiments on surface oil dispersion led to the following quantitative relations:a)an empirical relation for the oil entrainment rate (dispersed oil mass per unit time), as a function of the oil type, oil layer thickness, breaking-wave energy and temperature;b)the droplet size distribution as a function of the above parameters;c)the intrusion depth of oil droplets related to the wave height.The experiments with submerged oil resulted in relations for the droplet size distribution in dependence of various parameters. The empirical relations are applicable in mathematical models for calculation of natural dispersion of oil in the sea, with given hydrodynamic conditions and breaking wave statistics.
Effects of oil on marine organisms are categorized as:(1) direct lethal toxicity; (2) sub-lethal disruption of physiological behavioral activities: (3) effects of direct coating: (4) incorporation of hydrocarbons: and (5) alteration of habitat, especially substrate character. Occurrence of one or more of these effects depends on the composition of oil to which organisms are exposed. Weathering processes significantly alter the composition of spilled oil, resulting in wide variations in biological effects. A set of oil fractions, distinguished by boiling point range and hydrocarbon type, provide a convenient basis for including the important chemical aspects of the impact problem. Adult marine organisms may exhibit lethal toxic effects from exposures to 1–100 ppm soluble aromatic derivative hydrocarbons (SAD). Sub-lethal effects may be caused by SAD concentrations in the range 10–100 ppb. Oil exposed to the atmosphere for 1–2 days loses soluble fractions and non-toxic effects, habitat alteration and coating, become important effects. Effects of several spills are reviewed in light of the above considerations.
A statistical analysis of 45 oil spills shows a weak log-log correlation between spill volume and numbers of seabirds killed. This relationship cannot be used to predict mortality and loses its significance if one extreme case is omitted. The data show the wide variance in mortality in spills of all sizes. A loose ‘rule-of-thumb’ that is often used in poorly documented spills is that the overall mortality is ten times the actual body count. There is no justification for this notion. The mean estimate used is 4–5 times the body count, but each spill should be examined independently.
Ambient air samples from a traffic intersection, an urban site and a petrochemical-industrial site (PCI) were collected by using several dry deposition plates, two Microorifice uniform deposited impactors (MOUDIs), one Noll Rotary Impactor (NRI) and several PS-1 (General Metal Work) samplers from March 1994 to June 1995 in southern Taiwan, to characterize the atmospheric particle-bound PAH content of these three areas. Twenty-one individual polycyclic aromatic hydrocarbons (PAHs) were analyzed primarily by using a gas chromatograph/mass spectrometer (GC/MS). In general, the sub-micron particles have a higher PAH content. This is due to the fact that soot from combustion sources consists primarily of fine particles and has a high PAH content. In addition, a smaller particle has a higher specific surface area and therefore may contain more organic carbon, which allows for more PAH adsorption. For a particle size range between 0.31 and 3.2 μm, both Urban/Traffic and PCI/Traffic ratios of particle-bound total-PAH content have the lowest values, ranging from 0.25 to 0.28 (mean = 0.26) and from 0.07 to 0.13 (mean = 0.10), respectively. This indicates that, during the accumulation process, the PAH mass shifted from a particle phase to a gas phase, or the particles aggregated with lower PAH-content particles, resulting in a reduction in particle-bound PAH content. By using the particle size distribution data, the dry deposition model in this study can provide a good prediction for the PAH content of dry deposition materials. In general, lower molecular weight PAHs had a larger fraction of dry deposition flux contributed by the gas phase; for 2-ring PAH (50.4, 46.3 and 28.4%), 3-ring PAHs (15.2, 15.4 and 11.7%) and 4-ring PAHs (13.0, 3.60 and 5.01%) for the traffic intersection, urban and PCI sites, respectively. For higher molecular weight PAHs—5-ring, 6-ring and 7-ring PAHs—their cumulation fraction (F%) of dry deposition flux contributed by the gas phase was lower than 3.26%. At the traffic intersection, urban and PCI sites, the mass median diameter of dry deposition materials (MMDF) of individual PAHs was between 25.3 and 49.6 μm, between 27.6 and 43.9 μm, and between 19.1 and 41.9 μm, respectively. This is due to the fact that PAH dry-deposition primarily resulted from gravitational settling of the coarse particulates (> 10 μm).
Concerns have been raised about whether the Deepwater Horizon oil spill cleanup workers experienced adverse health effects from exposure to airborne benzene, toluene, ethylbenzene, and xylene (BTEX) which volatilized from surfaced oil. Thus, we analyzed the nearly 20 000 BTEX measurements of breathing zone air samples of offshore cleanup workers taken during the six months following the incident (made publicly available by British Petroleum). The measurements indicate that 99% of the measurements taken prior to capping the well were 32-, 510-, 360-, and 77-fold lower than the U.S. Occupational Safety and Health Administration's Permissible Exposure Limits (PELs) for BTEX, respectively. BTEX measurements did not decrease appreciably during the three months after the well was capped. Moreover, the magnitudes of these data were similar to measurements from ships not involved in oil slick remediation, suggesting that the BTEX measurements were primarily due to engine exhaust rather than the oil slick. To supplement the data analysis, two modeling approaches were employed to estimate airborne BTEX concentrations under a variety of conditions (e.g., oil slick thickness, wind velocity). The modeling results corroborated that BTEX concentrations from the oil were well below PELs and that the oil was not the primary contributor to the measured BTEX.
A large fraction of atmospheric aerosols are derived from organic compounds with various volatilities. A National Oceanic and Atmospheric Administration (NOAA) WP-3D research aircraft made airborne measurements of the gaseous and aerosol composition of air over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico that occurred from April to August 2010. A narrow plume of hydrocarbons was observed downwind of DWH that is attributed to the evaporation of fresh oil on the sea surface. A much wider plume with high concentrations of organic aerosol (>25 micrograms per cubic meter) was attributed to the formation of secondary organic aerosol (SOA) from unmeasured, less volatile hydrocarbons that were emitted from a wider area around DWH. These observations provide direct and compelling evidence for the importance of formation of SOA from less volatile hydrocarbons.
Response actions to the Deepwater Horizon oil spill included the injection of ∼771,000 gallons (2,900,000 L) of chemical dispersant into the flow of oil near the seafloor. Prior to this incident, no deepwater applications of dispersant had been conducted, and thus no data exist on the environmental fate of dispersants in deepwater. We used ultrahigh resolution mass spectrometry and liquid chromatography with tandem mass spectrometry (LC/MS/MS) to identify and quantify one key ingredient of the dispersant, the anionic surfactant DOSS (dioctyl sodium sulfosuccinate), in the Gulf of Mexico deepwater during active flow and again after flow had ceased. Here we show that DOSS was sequestered in deepwater hydrocarbon plumes at 1000-1200 m water depth and did not intermingle with surface dispersant applications. Further, its concentration distribution was consistent with conservative transport and dilution at depth and it persisted up to 300 km from the well, 64 days after deepwater dispersant applications ceased. We conclude that DOSS was selectively associated with the oil and gas phases in the deepwater plume, yet underwent negligible, or slow, rates of biodegradation in the affected waters. These results provide important constraints on accurate modeling of the deepwater plume and critical geochemical contexts for future toxicological studies.
The fiery destruction of an oil drilling platform in the Gulf of Mexico on 20 April may have triggered one of the worst environmental
disasters in U.S. history. The impact of the crisis, which began with the deaths of 11 workers and then simmered for several
days before an expanding oil slick grabbed worldwide attention, promises to test the federal government's ability to protect
habitat, wildlife, and the economic well-being of a four-state region on a scale never before imagined.
Sorbent tubes/traps are widely used in combination with gas chromatographic (GC) analytical methods to monitor the vapour-phase fraction of organic compounds in air. Target compounds range in volatility from acetylene and freons to phthalates and PCBs and include apolar, polar and reactive species. Airborne vapour concentrations will vary depending on the nature of the location, nearby pollution sources, weather conditions, etc. Levels can range from low percent concentrations in stack and vent emissions to low part per trillion (ppt) levels in ultra-clean outdoor locations. Hundreds, even thousands of different compounds may be present in any given atmosphere. GC is commonly used in combination with mass spectrometry (MS) detection especially for environmental monitoring or for screening uncharacterised workplace atmospheres. Given the complexity and variability of organic vapours in air, no one sampling approach suits every monitoring scenario. A variety of different sampling strategies and sorbent media have been developed to address specific applications. Key sorbent-based examples include: active (pumped) sampling onto tubes packed with one or more sorbents held at ambient temperature; diffusive (passive) sampling onto sorbent tubes/cartridges; on-line sampling of air/gas streams into cooled sorbent traps; and transfer of air samples from containers (canisters, Tedlar) bags, etc.) into cooled sorbent focusing traps. Whichever sampling approach is selected, subsequent analysis almost always involves either solvent extraction or thermal desorption (TD) prior to GC(/MS) analysis. The overall performance of the air monitoring method will depend heavily on appropriate selection of key sampling and analytical parameters. This comprehensive review of air monitoring using sorbent tubes/traps is divided into 2 parts. (1) Sorbent-based air sampling option. (2) Sorbent selection and other aspects of optimizing sorbent-based air monitoring methods. The paper presents current state-of-the-art and recent developments in relevant areas such as sorbent research, sampler design, enhanced approaches to analytical quality assurance and on-tube derivatisation.
This research compared the sampling efficiencies of open- and closed-face 37 mm filter cassettes and an experimental cassette with a tapered inlet. The experiment involved challenging the cassettes with various aerosol sizes up to 24 micron Mass Median Aerodynamic Diameter (MMAD) in a wind tunnel operated at 100 cm/sec. Sampling efficiencies were determined by comparing cassette mass concentration measurements to paired isokinetic samples. It was found that sampling efficiencies dropped with increasing particle size and that the cassette with the tapered entry offered no improvement to sampling efficiency. Sampling efficiency appeared to be improved by placing cassettes on a manikin to simulate personal sampling.
Particle behavior in the human respiratory tract is well understood and can be used to (1) estimate particle deposition in all regions of the respiratory tract for any aerosol respired at any pattern, and (2) optimize targeting of all regions of the respiratory tract in respiratory drug delivery. Extrathoracic and alveolar regions can effectively be targeted with mono- and polydisperse aerosols respired steadily. Effective targeting of the bronchial region can only be achieved with bolus inhalations. When particles are suspended in a gas heavier than air, targeting the alveolar region can be enhanced.
The purpose of this study was to evaluate exposure conditions and acute health effects in subjects participating in the Prestige oil spill cleanup activities and the association between these and the nature of the work and use of protection devices in the regions of Asturias and Cantabria (Spain). The sample comprised 400 subjects in each region, selected from a random sampling of all persons involved in cleanup activities, stratified by type of worker and number of working days. Data were obtained via a structured questionnaire and included information on specific tasks, number of working days, use of protective materials, and acute health effects. These effects were classified into two broad groups: injuries and toxic effects. Data analysis was performed using complex survey methods. Significant differences between groups were evaluated using Pearson's chi(2) test. Unconditional logistic regression was used to compute odds ratios and 95% confidence intervals. Bird cleaners accounted for the highest prevalence of injuries (19% presented with lesions). Working more than 20 days in highly polluted areas was associated with increased risk of injury in all workers. Occurrence of toxic effects was higher among seamen, possibly due to higher exposure to fuel oil and its components. Toxic effects were more frequent among those working longer than 20 days in highly polluted areas, performing three or more different cleaning activities, having skin contact with fuel oil on head/neck or upper limbs, and eating while in contact with fuel or perceiving disturbing odors. No severe disorders were identified among individuals who performed these tasks. However, potential health impact should be considered when organizing cleanup activities in similar environmental disasters.