Toxicity Of Hydrocarbons Research Articles

Accidental poisoning its magnitude and implications in children

incidence, and mortality in pediatric population.Objective: Estimating the magnitude and assessing the pattern of AP in children was the primary objective. Describing the affected age group, common agents, and assessment of clinical features were the secondary objectives.Materials & Methods: Children aged 1month- 12years with history of AP were included; those with allergic reactions to plant products, food and idiosyncratic reactions to drugs were excluded.Result: 101 children accounted for 1.7% of total pediatric admission. Accidental ingestion of poisons (90.09%) and poisoning due to insect and snake bites (9.90%) were reported. Males (n=62) outnumbered females. Patients from urban area (68.2 %), children aged1-3 years (56.43%) wereaffected the most. All incidents were unintentional and occured in the home surroundings.April (n=21), March (n=20) recorded higher number followed by December (n=14). Hydrocarbon poisoning (43.56%) was most common followed by poisoning due to medicaments (18.8 %,), chemicals (12.87%), and food poisoning (9.90%). Insect bites & stings were seen in 9.90%. Supportive treatment was given to 49.5%, further gastric absorption prevented in 24.45 % and specific antidote to 7.9% patients.Three patients died due to scorpion bite, Phenytoin and kerosene ingestion.Conclusion: AP is a preventable emergency. Incidence, agents, clinical features, treatment administered and therapeutic outcome of AP in children are comparable to the available national data. Preventive measures, strict legislative actions and restriction of availability of hazardous chemicals will reduce the incidence.

A method linking the toxic effects at community-level with contaminant concentrations

In this study, we developed a method to quantify and link the toxic effects in community-level ecosystems with concentrations of petroleum hydrocarbons. The densities of Platymonas helgolandica var. tsingtaoensis, Isochrysis galbana, and Brachionus plicatilis in single-species tests and customized ecosystems were examined in response to a concentration gradient of petroleum hydrocarbons ranging from 0 to 8.0mgL−1. A three-population ecological model with interspecies competition-grazing relationships was used to characterize population sizes with concentrations of petroleum hydrocarbons. A threshold concentration of the simplified plankton ecosystem of 0.376mgL−1 for petroleum hydrocarbons was calculated from the proposed model, which was higher than the no-effect concentration of 0.056mgL−1 derived from the single-species toxicity tests and the predicted no-effect concentration of 0.076mgL−1 calculated from the species sensitivity distribution. This finding indicates that interspecies competition and grazing reduced the toxic effect of petroleum hydrocarbons at the community level. The sensitivity analysis for model parameters demonstrates that plankton population biomasses are highly sensitive to filtration rates. Antagonism between interspecies interactions and petroleum hydrocarbon toxicity was attributed to the reduced filtration rate and zooplankton grazing pressure. The proposed method is a simple means to address the concern regarding the impacts of ecological interactions on ecological risk assessments of pollutants.

Evaluation of the Efficiency of a Biofilter System’s Phenol Removal From Wastewater

Phenol is a toxic hydrocarbon that has been found in the wastewater of several industries, including the petroleum and petrochemical industries. The discharge of untreated wastewater from these industries causes environmental pollution, especially in water. The aim of this study was to evaluate the efficiency of phenol removal from wastewater using a biofiltration system. In this experimental study, a cylindrical plexiglass biofilter reactor with an effective volume of 12 liters was used. A total of 30 pcs of plastic grid discs were placed inside the reactor by plastic pipes to maintain the biofilm media in the reactor. The microorganisms used in this study were obtained from the biological sludge of a municipal wastewater treatment plant. The reproduction and adaptation of the microorganisms to 500 mg/L of phenol lasted three months. The effects of pH, phenol, nitrogen, phosphorus, glucose concentration, and hydraulic retention time on the biofilter system’s performance was evaluated. The results of this study showed that in optimal conditions, this system can reduce the phenol concentration from 500 mg/L to zero within about 4 hr. Maximum efficiency occurred in pH = 7, and the proper COD/N/P ratio was 100/10/2, respectively. In general, this biofilter system is capable of removing 500 mg/L of phenol concentrations and an organic load of 4 - 4.5 kg COD/m3 .d within 4 - 5 hr. with high efficiency

Biosynthesis of selenium nanoparticles by Azoarcus sp. CIB.

BackgroundDifferent bacteria have been reported so far that link selenite resistance to the production of metallic selenium nanoparticles (SeNPs). Although SeNPs have many biotechnological applications in diverse areas, the molecular mechanisms involved in their microbial genesis are not fully understood. The Azoarcus genus is a physiologically versatile group of beta-proteobacteria of great environmental relevance. Azoarcus sp. CIB is a facultative anaerobe that combines the ability to degrade under aerobic and/or anaerobic conditions a wide range of aromatic compounds, including some toxic hydrocarbons such as toluene and m-xylene, with an endophytic life style in the root of rice. We unravel here an additional physiological feature of the strain CIB that is related to its resistance to selenium oxyanions and the formation of SeNPs.ResultsThis work is the first report of a member of the Azoarcus genus that is able to anaerobically grow in the presence of selenite. Electron microscopy preparations and X-ray spectroscopy analyses demonstrate the reduction of selenite to spherical electron-dense SeNPs whose average size was 123 ± 35 nm of diameter. Our data suggest that the main molecular mechanism of selenite resistance resides on an energy-dependent selenite exporter. Azoarcus cells trigger the synthesis of SeNPs when they reach the stationary-phase of growth, and either the exhaustion of electron donor or acceptor, both of which lead to starvation conditions, produce the reduction of selenite to red elemental selenium. Azoarcus becomes a promising biocatalyst, either as whole cells or cellular extracts, for the anaerobic and/or aerobic green synthesis of SeNPs.ConclusionsAzoarcus turns out to be a new eco-friendly system to reduce selenite and produce spherical SeNPs. Moreover, this is the first report of a rice endophyte able to produce SeNPs. Since Azoarcus is also able to degrade both aerobically and anaerobically toxic aromatic compounds of great environmental concern, it becomes a suitable candidate for a more sustainable agricultural practice and for bioremediation strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0510-y) contains supplementary material, which is available to authorized users.

Emission, distribution and toxicity of polycyclic aromatic hydrocarbons (PAHs) during municipal solid waste (MSW) and coal co-combustion

Emission and distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) were investigated during municipal solid waste (MSW) and coal combustion alone and MSW/coal blend (MSW weight fraction of 25%) co-combustion within a temperature range of 500°C–900°C. The results showed that for all combustion experiments, flue gas occupied the highest proportion of total PAHs and fly ash contained more high-ring PAHs. Moreover, the 3- and 4-ring PAHs accounted for the majority of total PAHs and Ant or Phe had the highest concentrations. Compared to coal, MSW combustion generated high levels of total PAHs with the range of 111.28μg/g–10,047.22μg/g and had high toxicity equivalent value (TEQ). MSW/coal co-combustion generated the smallest amounts of total PAHs and had the lowest TEQ than MSW and coal combustion alone. Significant synergistic interactions occurred between MSW and coal during co-combustion and the interactions suppressed the formation of PAHs, especially hazardous high-ring PAHs and decreased the TEQ. The present study indicated that the reduction of the yield and toxicity of PAHs can be achieved by co-combustion of MSW and coal.

A study of accidental ingestion of hydrocarbons in children in a medical college hospital in central Kerala

Background: The accidental ingestion of various chemicals especially the hydrocarbons are seen worldwide in the paediatric population. Inspite of all awareness programmes in the community hydrocarbons especially petrol, diesel, turpentine and kerosene are always in the reach of children. The side effects and clinical spectrum is alarming after ingestion. So it is vital to prevent hydrocarbon ingestion. Objective: To understand the clinical profile of accidental ingestion of hydrocarbons (AIH) in children, assess the radiological changes and treatment. Materials and Methods: The retrospective study was conducted analysing the hospital records of children hospitalized between January 1st 2010 and December 31st 2015 with accidental poisoning due to various causes in the paediatric intensive care unit (PICU) with special reference to AIH. A standard proforma included age, sex of the children, types of poisoning agents including hydrocarbons (HC), clinical presentations and treatment given. Results: In the PICU out of a total of 5806 patients admitted, 401 (6.9%) were due to acute poisoning. Among them AIH was noted in 118 (29.4%) patients. These children were admitted initially in the PICU stabilized and there was no mortality following AIH during the period of study. Conclusion: AIH is a common cause of poisoning in children. The main reason is the easy availability in the house itself due to various reasons. The morbidity and mortality can be prevented by education of the society especially the care takers of the children in the community.

Modelling Inhibition Effects of Short-Chain Hydrocarbons on a Small-Pore Cu-Zeolite NH3-SCR Catalyst

NH3-SCR currently represents the leading technology for NOx abatement from lean exhaust gases, e.g. from diesel engines. Hydrocarbon (HC) slip onto the SCR catalyst can have a negative impact on its DeNOx performance. In order to better understand hydrocarbon poisoning, the influence of different light HCs on the catalytic activity of a small-pore Cu-zeolite has been investigated in a synthetic gas test rig. Based on these data and on further indications from the literature, an existing SCR kinetic model has been extended to represent major effects of light HCs on the behavior of zeolite SCR catalysts. The developed model is able to describe such effects in a simple but effective way.

Design and synthesis of core-shell structured meso-Cu-SSZ-13@mesoporous aluminosilicate catalyst for SCR of NOx with NH3: Enhancement of activity, hydrothermal stability and propene poisoning resistance

A core-shell structured composite material with a mesoporous aluminosilicate (MAS) shell and mesopore-containing SSZ-13 (meso-SSZ-13) core was first synthesized by combining controlled desilication with subsequent self-assembly. The corresponding catalyst was subsequently prepared by a copper ion-exchange method. This catalyst can simultaneously solve three major problems existing in the previous Cu-SSZ-13 catalyst for NOx emission control from diesel engine exhaust, i.e., low temperature activity, hydrothermal stability and propene poisoning resistance. In comparison with Cu-SSZ-13, the meso-Cu-SSZ-13@mesoporous aluminosilicate (meso-Cu-SSZ-13@MAS) catalyst showed higher SCR activity across the entire temperature range. This increase was observed due to increasing the amount of active Cu species (isolated Cu2+ ions) and fewer pore diffusion limitations. The MAS shell with a “concrete with crushed stone”-like mesostructure could prevent the dealumination of meso-SSZ-13 core effectively, and therefore enhanced the hydrothermal stability of the meso-Cu-SSZ-13@MAS catalyst. Additionally, meso-Cu-SSZ-13@MAS exhibited higher hydrocarbon poisoning resistance because its external surface has fewer active sites for propene oxidation reaction.

Bioremediation of petroleum contaminated soil to combat toxicity on Withania somnifera through seed priming with biosurfactant producing plant growth promoting rhizobacteria

Soil contaminated by Petroleum oil cannot be utilized for agricultural purposes due to hydrocarbon toxicity. Oil contaminated soil induces toxicity affecting germination, growth and productivity. Several technologies have been proposed for bioremediation of oil contaminated sites, but remediation through biosurfactant producing plant growth promontory rhizobacteria (PGPR) is considered to be most promising methods. In the present study the efficacy of seed priming on growth and pigment of Withania somnifera under petroleum toxicity is explored. Seeds of W. somnifera were primed with biosurfactant producing Pseudomonas sp. AJ15 with plant growth promoting traits having potentiality to utilized petroleum as carbon source. Results indicates that plant arose from priming seeds under various petroleum concentration expressed high values for all the parameters studied namely germination, shoot length, root length, fresh and dry weight and pigments (chlorophyll and carotenoid) as compared to non primed seed. Hence, the present study signifies that petroleum degrarding biosurfactant producing PGPR could be further used for management and detoxification of petroleum contaminated soils for growing economically important crops.

UVR-induced toxicity of sludge and polycyclic aromatic hydrocarbons on seed germination and seedling growth of Triticum aestivum L.

ABSTRACTThe depletion of the ozone layer and enhancement of solar radiation may exert an adverse influence on the ecosystem. Phototoxicity of sludge and polycyclic aromatic hydrocarbons (PAHs) under ultraviolet radiation (UVR) to seedling was studied. Seeds of wheat (Triticum aestivum) were planted in sludge and PAHs (anthracene (An), benzo(a)pyrene (BaP) and pyrene (Py)) with and without UVR. Toxicity of sludge increased in the presence of UVR in wheat. UVB radiation was found to be more hazardous than UVA radiation. Results demonstrated that An, BaP and Py induced phototoxicity at various concentrations (1–10 µg/mL) under UVA (1.5 mW/cm2) or UVB (1.08 J/cm2) exposure. The pattern of phototoxicity was An > Py > BaP to shoot length, root length, and fresh weight; chlorophyll, protein content, enzyme activity of catalase and α-amylase were reduced while the activity of superoxide dismutase and starch was enhanced. Reduction in seedling growth and biochemical parameters may be related to less photosynthesis, less nutritional uptake, and distortion of root cap. Thus, the synergistic effect may be due to alterations in photosynthesis, phytohormones, or nutritional uptake.

Spatial distribution and potential toxicity of polycyclic aromatic hydrocarbons in sediments from Liaohe River Basin, China.

The distribution and potential toxicity of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Liaohe River Basin were investigated in this study. Total concentrations of 16 PAHs (∑PAH16) ranged from 82.5 to 25374.4 μg/kg averaging 3149.2 μg/kg. Three predominant PAHs were fluoranthene, phenanthrene, and pyrene. In Liao River, two-to-three-ring PAHs were dominant taking up 67.2-92.5% of ∑PAH16, whereas sediments in Daliao River system mainly contained four-to-six-ring PAHs ranging from 47.8 to 83.7%. Both petrogenic and pyrogenic sources contributed to the PAH pollution based on diagnostic ratios. The empirical and mechanistic sediment quality guidelines were used to estimate the toxicity risk of PAHs to benthic organisms. The ∑PAH16 in all sediments were significantly lower than probable effect concentrations (PEC), while ∑PAH16 at nine sites of the Daliao River system were between threshold effect concentrations (TEC) and PEC, suggesting that adverse effects were possible at the nine sites. The only individual PAH was acenaphthene whose concentrations were above PEC at some sites, indicating its potential toxicity. Based upon equilibrium partitioning theory and narcosis model, the obtained toxic units for PAH mixtures at all sites were far less than one, implying that the levels of PAH mixtures were acceptable for the protection of benthic fauna. The two evaluation methods lead to the consistent results that benthic organisms inhabiting in the sediments of Liaohe River Basin have no or low risk of adverse effects resulting from exposure to PAHs.

A DFT-based toxicity QSAR study of aromatic hydrocarbons to Vibrio fischeri: Consideration of aqueous freely dissolved concentration

In the present study, quantitative structure–activity relationship (QSAR) techniques based on toxicity mechanism and density functional theory (DFT) descriptors were adopted to develop predictive models for the toxicity of alkylated and parent aromatic hydrocarbons to Vibrio fischeri. The acute toxicity data of 17 aromatic hydrocarbons from both literature and our experimental results were used to construct QSAR models by partial least squares (PLS) analysis. With consideration of the toxicity process, the partition of aromatic hydrocarbons between water phase and lipid phase and their interaction with the target biomolecule, the optimal QSAR model was obtained by introducing aqueous freely dissolved concentration. The high statistical values of R2 (0.956) and QCUM2 (0.942) indicated that the model has good goodness-of-fit, robustness and internal predictive power. The average molecular polarizability (α) and several selected thermodynamic parameters reflecting the intermolecular interactions played important roles in the partition of aromatic hydrocarbons between the water phase and biomembrane. Energy of the highest occupied molecular orbital (EHOMO) was the most influential descriptor which dominated the toxicity of aromatic hydrocarbons through the electron-transfer reaction with biomolecules. The results demonstrated that the adoption of freely dissolved concentration instead of nominal concentration was a beneficial attempt for toxicity QSAR modeling of hydrophobic organic chemicals.

Fatal Evolution in the Pneumonia Caused by Diesel Fuel Aspiration - Case Report.

Aspiration pneumonia in infants emerges as a result of deglutition disorders, congenital malformations and severe gastroesophageal reflux. Hydrocarbon pneumonitis is caused by the accidental ingestion and aspiration of hydrocarbons into the body. In children, it can be seen as a result of both the lack of monitoring and the tendency for the exploration of the environment. The accidental ingestion of a large quantity is quite rare due to the bad taste of hydrocarbons. Initially, the central nervous system is the one affected, followed by the respiratory system, causing the chemical pneumonia (through direct injury of the lung). Furthermore, we shall present the case of an 18 month infant with severe trauma as a result of the accidental ingestion of diesel, followed by vomiting and who was brought late to the hospital. The pneumothorax that emerged as a complication was remitted after the treatment, but the initially chemical and then mixed pneumonia through bacterial overinfection led to the infant’s death after 12 days of medical attention in the Anesthesia and Intensive Care Unit. The histopathological examination of the analyzed lung fragments did not point out any lipid or foam cells that are characteristic to this type of pathology, but which are not mentioned by the majority of toxicology textbooks and those of pathological anatomy, through the low rate of mortality and numerous factors that can lead to negative false results.

Detection of Mycobacterium Gilvum First Time from the Bathing Water of Leprosy Patient from Purulia, West Bengal

Introduction: Mycobacterium gilvum is a fast grower with smooth growth having pale yellow colour. This strain was first isolated from the sediment of the Grand Calumet River in North-western Indiana based on its ability to utilize pyrene, a toxic polycyclic hydrocarbon, as a growth substrate. Methods: The identification and characterization of this isolate was done by various conventional and molecular tests including 16S rDNA sequencing. Sequencing of the nearly complete 16S rRNA gene revealed a unique organism M.glivum, distantly related to M.vaccae group. Blast results showed similarity of these sequences with M.gilvum. Conclusion: Results might shed further light and its association with amoeba in the leprosy endemic area of this rare Mycobacterium species.

Purification of Oil Contaminated Wastewater Using Sri Lankan Vein Graphite

Oil contaminated wastewater comes from variety of sources such as crude oil production, oilrefinery, petrochemical industry, metal processing, lubricants, cooling agents, car washing,and restaurants, etc. Oil is a highly visible pollutant and it reduces the levels of dissolvedoxygen in water and increases the level of toxic hydrocarbons. Therefor it affects the aquaticlife and water environment.Water and oil cannot be easily separated from oil-water mixtures, as oil exists in droplets inthe oil-water mixture. Oil droplets which are greater than or equal to 150 microns is classifiedas free oil while oil droplets with size ranging between 20 and 150 microns are classified asdispersed oil mixture. Emulsified oil mixtures are oil-water mixtures with droplets smallerthan 20 microns and oil-water mixture with droplet sizes smaller than 5 microns are classifiedas soluble oil mixtures.High purity vein graphite available in Sri Lanka is well renowned for electrical conductivityand lubricity. Beside it also has higher adsorption capacity. In this study, vein graphite ofdifferent particle sizes (<65, 65-125, 125-150 and 150-500μm) with two purity grades (99+%and 95%) were used to treat oil-water mixtures (motor engine oil with distilled water) similarto service station waste water of different concentrations of oil.Minimum amount of graphite (weight) required to completely separate oil from water wasmeasured in each treatment. Most effective particle size of graphite for this treatment wasfound to be in the range of 125-150 μm. Oil separation capacity of high purity graphite (99+%) and less pure (95%) graphite was found to be similar to each other. Maximumconcentration of oil that can be treated with this method was found to be 400%. Final oilconcentrations of all samples treated with graphite were measured and the efficiency of thetreatment was found to be 99.98%.Keywords: Natural vein graphite, Absorption capacity, Waste water, Hydrocarbon

Consequences of Environmentally Hazardous Polycyclic Aromatic Hydrocarbon- Anthracene Treatment on Cyanobacteria

The study was aimed to determine the chronic toxicity of Polynuclear aromatic hydrocarbon – Anthracene in response to pigments and metabolic study on three different cyanobacterial species such as Synechocystis sp., Anabaena fertilissima, and Nostoc muscorum. Test organisms were treated at different doses and encountered LC50/Mean Lethal Concentration (at which 50% lethality/ growth reduction occur) separately at 7.0 ppm for Synechocystis sp, 5.0 ppm for Anabaena fertilissima and 1.5 ppm for Nostoc muscorum. The influence of anthracene on pigments, metabolites and enzymes was carried out. The test doses caused concentration dependent and decreased pigments like carotenoids and phycobilliproteins. Depletion of carbohydrate by 65 to 80% and proteins by 58 to 78% was encountered with rise in Anthracene concentrations after 16th day exposure in case of Synechocystis sp however, phenols were found to raise by 26 to 37% with increased anthracene concentrations. Similar trend also observed in other two tested blue green algae. Thus the Synechocystis sp.is more tolerant to anthracene treatments as compare to Anabaena fertillissima but Nostoc muscorum showed highest sensitivity to anthracene.Int J Appl Sci Biotechnol, Vol 3(3): 381-386

Photochemical degradation increases polycyclic aromatic hydrocarbon (PAH) toxicity to the grouper Epinephelus marginatus as assessed by multiple biomarkers.

The effects of halogen-light-irradiated and non-irradiated PAHs on the grouper Epinephelus marginatus were assessed through biomarkers including morphometric parameters, liver histopathology, biliary PAH concentration, genetic alterations, and enzyme activity modulation. E. marginatus juveniles were divided into three groups: control (C), non-irradiated PAHs (PAHs1), and irradiated PAHs (PAHs2). Test groups were exposed for 14 days to a 0.5 ppm PAH solution in the semi-static system. After this period, fish were anesthetized with benzocaine (2%) and peripheric blood was collected by caudal puncture. Blood smears were prepared and stained with propidium iodide. Fish livers were collected, fixed in McDowell's solution, embedded in paraplast, thin-sectioned, and stained with hematoxylin-eosin (H&E). For biochemical analyses including superoxide dismutase, catalase, and glutathione S-transferase activities, fish livers were collected and preserved in liquid nitrogen. Water samples were analyzed using gas chromatography-mass spectrometry (GC-MS) and bile synchronous fluorescence spectroscopy. Fish in the PAHs2 group had micronuclei (MN) in blood cells, as well as significant differences in nuclear morphology (NMA). Significant morphological alterations were observed in the livers from fish exposed to PAHs as well as inhibition of the catalase activity. Our results show that irradiation altered the bioavailability of PAHs, especially benzanthracene, which has great impact in aquatic ecosystems. Among the consequences of physical and chemical changes to PAHs, we observed a significant increase in NMA and MN incidence in E. marginatus erythrocytes, indicating the potential initiation of mutagenic and carcinogenic processes.

Extractive Dearomatization of Naphthalane Oil Fraction with Ionic Liquid and -N-Methyl-2-Pyrrolidone

In the article are given an analysis of the results of researches carried out for the purpose of selective treatment of the Naphthalane oil fraction boiling at 260-3400C with ionic liquid (IL) -morfolinphormiate synthesized on the basis formic acid + morpholine and - N-methyl-2-pyrrolidon (N-MP) and as an extractant. The aim is to remove poisonous components - sulfur compounds and toxic carcinogenic polynuclear aromatic hydrocarbons in order to improve therapeutic properties of Naphthalane oil cut. For this purpose we have used extraction method. On the basis of the conducted researches the role of -N-methyl-2-pyrrolidone and IL-morpholinephormiatee in extraction conditions have been determined in selective treatment of Nafthalan oil, according to the results of spectral analysis residual amount of aromatic hydrocarbons decreased from 18.5% wt accordance to 2%, 1.5%. As well as the amount of sulphur decreased from 0.0354% to 0.010%, 0.011% and 0.019%.In the next stage the treated raffinates with N-methyl-2-pyrrolidone has been purified on silica. In a result amount of aromatic hydrocarbons drastically decrease to be 0.07% and 0.02%. As a result we aquire transparency and at the same time the percentage amount of aromatic hydrocarbons drastically decreased from 2% to 0,07%, 1.5%, to 0.02%. Raffinates obtained in a 2-4 stage dearomatization with N-MP and IL. Raffinate are measured on NMR, UV and IR spectral analysis.

Risk-Based Analysis and Engineering of Safe Distances Between Occupied Structures and Processing Equipment

Summary Determining the optimal distance between explosive, flammable, and toxic hydrocarbon sources and occupied structures is a constant concern for engineers working to design safe facilities. Over the years, many incidents have occurred during which workers were injured or killed by flying shards of glass and debris, explosive forces, fire, or exposure to toxic gases when occupied structures were not located properly in relation to process equipment. This paper presents newly developed techniques to allow the engineer to locate occupied structures optimally to ensure that the risk of harm to personnel is minimized. The analysis of determining the placement for an occupied structure involves many variables that the engineer must evaluate. These variables include the properties of the hydrocarbons that are being processed, toxic components (e.g., hydrogen sulfide), operating parameters, loss-of-containment scenarios, prevailing winds, occupancy loads, building construction, safety systems, and operating and maintenance practices. Each of these different variables can have a significant impact on where a building should be located within or adjacent to a facility. The engineer must consider these variables for impacts to the structure cause by fire, blast, or toxic-gas infiltration. Recognized industry best practices and regulatory requirements require that blast loads, which commonly present the most-severe hazard to a building, be evaluated when locating an occupied structure. Often, it is not practical to design or locate a building to withstand the ’worst-case’ blast scenario. For this reason, a risk-based approach, in conformance with recognized best practices, has been developed to site buildings properly at oil and gas facilities. This paper presents a viable risk-based approach for the siting of occupied structures at oil and gas facilities. The technique presented in the paper enables the engineer to gather the information needed for the analysis quickly, evaluate credible scenarios, and then make the necessary calculations to determine impacts to the occupants. The result of using this technique is that an occupied structure is located properly and constructed to reduce the risk of harm to the occupants to a tolerable level.

Variations in the Toxic Effects of Petroleum Hydrocarbons to Isochrysis galbana under Different Environmental Factors

&lt;p&gt;&lt;span style="font-family: Times New Roman;"&gt;In order to study the toxic effect of petroleum hydrocarbons on marine phytoplankton, &lt;em&gt;Isochrysis galbana&lt;/em&gt; was investigated by using the index of 96 h-EC50 and population growth. The results showed that the 96 h-EC50 increased significantly (P&lt;/span&gt;＜&lt;span style="font-family: Times New Roman;"&gt;0.05) when temperature rising from 15&lt;/span&gt;℃&lt;span style="font-family: Times New Roman;"&gt; to 25&lt;/span&gt;℃&lt;span style="font-family: Times New Roman;"&gt;. The intrinsic growth rates (r) increased but the time to enter into the stationary phase shortened from 15&lt;/span&gt;℃&lt;span style="font-family: Times New Roman;"&gt; to 25&lt;/span&gt;℃&lt;span style="font-family: Times New Roman;"&gt;, and the carrying capability (K) reached highest at 20&lt;/span&gt;℃&lt;span style="font-family: Times New Roman;"&gt;. In addition, the 96 h-EC50 in the salinity of 31 is higher than that in other salinities and the carrying capability reached the highest level. Moreover, the 96 h-EC50 increased when the pH changing from 6.5 to 8.1, but decreased when the pH more than 8.1. The results also show that the maximum (K) and (r), and the shortest time into stationary phases in the natural pH of seawater. It shows the minimum (K) in the low pH of 6.5. There is no significant (P&lt;/span&gt;＞&lt;span style="font-family: Times New Roman;"&gt;0.05) between pH7.5 and pH 8.5. In conclusion, temperature, pH and salinity did influence the toxicity of petroleum hydrocarbon to the microalgae (&lt;em&gt;I. galbana&lt;/em&gt;).&lt;/span&gt;&lt;/p&gt;