Levels Of Total Hydrocarbons Research Articles

Effect of the Intake Valve Opening Timings and Fuel Injection Pressures on the Exhaust Emission Characteristics of a Gasoline Engine at Part Load Condition

This work has investigated the exhaust emissions such as Total Hydrocarbon (THC), Nitrogen Oxides(NOx), and Particulate Matter (PM) characteristics emitted from the tail-pipe of a continuously variable valve timing (CVVT) gasoline-fueled engine with different intake valve opening timings and injection pressures at the part load condition. Valve overlap period was varied from 40°CA to 10°CA and fuel injection pressure was increased from 3.5 bar to 5.0 bar. THC and NOx emissions decreased as intake valve opening timing was advanced regardless of fuel injection pressure. When the fuel was injected with the condition of 5.0 bar at all of valve overlap ranges, THC levels were reduced by 55%. NOx concentrations were diminished about 75% as valve overlap increased. PM size distributions were analyzed as bi-modal type of the nucleation and accumulation mode. Comparing with fuel injection pressures, PM emission levels were decreased at high pressure injection of 5.0 bar condition.

Levels of Petroleum Hydrocarbons and some Heavy Metals in Tissues of <i>Tympanotonus fuscatus</i> periwinkles from Warri river of Niger Delta Area of Nigeria

The levels of petroleum hydrocarbons and some heavy metals in the tissues of Tympanotomus fuscatus periwinkle from Warri River of Niger Delta area were investigated. Six hundred samples of periwinklescollected fortnightly for a period of six months from three stations (Jala. Ubeji and Suoroagbene-control) along Warri River were analyzed using Atomic Absorption Spectrophotometry for the determination of heavy metals. The mean levels of total hydrocarbon varied from 0.0045mg/g to 0.093 mg/g and mean lead (Pb) levels varied from 0.0023 ppmto 0.046 ppm. Mercury (Hg) and Cadmium (Cd) were below the instrument detection limit of

Inhalation Exposure to Jet Fuel (JP8) Among U.S. Air Force Personnel

As jet fuel is a common occupational exposure among military and civilian populations, this study was conducted to characterize jet fuel (JP8) exposure among active duty U.S. Air Force personnel. Personnel (n = 24) were divided a priori into high, moderate, and low exposure groups. Questionnaires and personal air samples (breathing zone) were collected from each worker over 3 consecutive days (72 worker-days) and analyzed for total hydrocarbons (THC), benzene, toluene, ethylbenzene, xylenes, and naphthalene. Air samples were collected from inside the fuel tank and analyzed for the same analytes. Linear mixed-effects models were used to evaluate the exposure data. Our results show that the correlation of THC (a measure of overall JP8 inhalation exposure) with all other analytes was moderate to strong in the a priori high and moderate exposure groups combined. Inhalation exposure to all analytes varied significantly by self-reported JP8 exposure (THC levels higher among workers reporting JP8 exposure), a priori exposure group (THC levels in high group > moderate group > low group), and more specific job task groupings (THC levels among workers in fuel systems hangar group > refueling maintenance group > fuel systems office group > fuel handling group > clinic group), with task groupings explaining the most between-worker variability. Among highly exposed workers, statistically significant job task-related predictors of inhalation exposure to THC indicated that increased time in the hangar, working close to the fuel tank (inside > less than 25 ft > greater than 25 ft), primary job (entrant > attendant/runner/fireguard > outside hangar), and performing various tasks near the fuel tank, such as searching for a leak, resulted in higher JP8 exposure. This study shows that while a priori exposure groups were useful in distinguishing JP8 exposure levels, job task-based categories should be considered in epidemiologic study designs to improve exposure classification. Finally, the strong correlation of THC with naphthalene suggests that naphthalene may be an appropriate surrogate of JP8 exposure. [Supplementary materials are available for this article. Go to the publisher's online edition of the Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a pdf file containing a table detailing concentrations of JP8 components.]

Even-numbered n-alkanes/n-alkenes predominance in surface sediments of Gabes Gulf in Tunisia

Hydrocarbons in surface sediments were studied quantitatively and qualitatively in 18 stations along the coastline of Gabes Gulf in Tunisia. The results show that the total hydrocarbon levels vary along a wide range from 90 to 1,800 ppm. The GC–MS profiles of aliphatic hydrocarbons vary according to the stations and show that the hydrocarbons were derived from various sources. A special feature prevalent in several stations was identified: aliphatic hydrocarbons with distinctive chemical features. This includes a high abundance of even-numbered n-alkanes (n-C14–n-C26, maximizing at n-C18, n-C20 and n-C22) and n-alk-1-enes (n-C14:1–n-C24:1, maximizing at n-C16:1, n-C18:1, n-C20:1 and n-C22:1). This unusual predominance of even-numbered n-alkanes/alkenes is reported for the first time in the Gulf of Gabes and it thus contributes to the information on the rare occurrence of such distributions in the geosphere.

EVALUATION OF TOTAL HYDROCARBON LEVELS IN SOME AQUATIC MEDIA IN AN OIL POLLUTED MANGROVE WETLAND IN THE NIGER DELTA

The total hydrocarbon (THC) levels in the surface waters, sediments and biota in an oil polluted mangrove wetland located in the Niger Delta Nigeria, were studied between November 2001 and October 2002. Result showed elevated THC mean levels in water (23.6 + 4.3mg/l), sediment (386.44 ± 50.28 μg/g), Tympanotonus fuscatus (Periwinkle) (449.30 ± 55.42 μg/g) and Periophthalmus papillio (Mudskipper) (278.57 ± 34.57 μg/g), indicating a polluted environment. THC levels in water at the wellhead stations were above 10mg/l being the maximum recommended limit by the Federal Ministry of Environment (FMENV) Nigeria. There was a pronounced seasonal variability with the highest being in the dry season (P < 0.05) due to the higher level of increased oil activity in that season. THC levels in water correlated significantly (r = 0.927) with THC levels in the sediment (P < 0.01). The implication is that as the THC remains within the surface water column in relation to the sediment the more the organisms in the environment are impacted. This is shown by the significant correlations (P<0.01) of THC between the organisms and their surrounding media. The high levels of THC in the surface water and sediments of these stations suggest that aquatic life water quality may adversely influence biological functions of exposed species, while the level in the Tympanotonus fuscatus and the Periophthalmus papillio calls for concern as it can have some health-risk implications in man who is the final consumer.

Hydrocarbons in Seawater and Water Extract of Jarzouna-Bizerte Coastal of Tunisia (Mediterranean Sea): Petroleum Origin Investigation Around Refinery Rejection Place

We investigated the composition and spatial distribution of non-aromatic, aromatic and polycyclic aromatic hydrocarbons (PAH) found in seawater and water extracted from refinery rejection effluents in the coastal area of Jarzouna, Tunisia. Water samples were analysed for hydrocarbons by gas chromatography. Total hydrocarbon levels ranged between 46 and 76 mg/L in seawater samples and between 28 and 102 mg/L in water extracts. The sites nearest to the oil refinery were found to be chronically contaminated by total petroleum hydrocarbons based on aliphatic biomarkers. PAH contamination is generally much more pyrolytic than petrogenic. This study helped to determine the concentration, spatial distribution, compound profiles and possible sources of various petroleum compounds, thus contributing significantly to a greater understanding of the background of petroleum hydrocarbon levels, the various types of anthropogenic input involved and the contribution of the Societe Tunisienne des Industries de Raffinage refinery’s effluents in terms of hydrocarbon pollution.

Social Context Influences Chemical Communication in D. melanogaster Males

Chemical communication mediates social interactions in insects. For the fruit fly, D. melanogaster, the chemical display is a key fitness trait because it leads to mating. An exchange of cues that resembles a dialogue between males and females is enacted by pheromones, chemical signals that pass between individual flies to alter physiology and behavior. Chemical signals also affect the timing of locomotor activity and sleep. We investigated genetic and environmental determinants of chemical communication. To evaluate the role of the social environment, we extracted a chemical blend from individual males selected from groups composed of one genotype and compared these extracts to those from groups of mixed genotypes. To evaluate the role of the physical environment, these comparisons were performed under a light-dark cycle or in constant darkness. Here, we show that chemical signaling is affected by the social environment, light-dark cycle, and genotype as well as the complex interplay of these variables. Gene-by-environment interactions produce highly significant effects on chemical signaling. We also examined individual responses within the groups. Strikingly, the response of one wild-type fly to another is modulated by the genotypic composition of his neighbors. Chemical signaling in D. melanogaster may be a "fickle" trait that depends on the individual's social background.

A Comprehensive Two-Dimensional Gas Chromatography Method for Analyzing Extractable Petroleum Hydrocarbons in Water and Soil

A flow-switching two-dimensional gas chromatography (GCxGC) apparatus has been constructed that can operate at temperatures as high as 340 degrees C. This system is employed to analyze complex hydrocarbon mixtures such as diesel fuel, gas-oil, motor oil, and petroleum contaminated environmental samples. The GCxGC system generates two-dimensional chromatograms with minimal overlap between the aliphatic and aromatic regions This allows these compound classes to be independently quantitated without prior fractionation. The GCxGC system is used to analyze extracts of spiked water samples, wastewater, and soil. The accuracy of the method is compared to that of the Massachusetts Extractable Petroleum Hydrocarbons (MA EPH) method. The GCxGC system generates a quantitative accuracy similar to the MA EPH method for the analysis of spiked water samples. The GCxGC method and the MA EPH method generate comparable levels of total hydrocarbons when wastewater is analyzed, but the GCxGC method detects a significantly higher aromatic content and lower aliphatic content. Both the GCxGC method and MA EPH method measure comparable levels of aromatics in the soil samples.

Treatment of Dyeing Wastewater by Using Positive Pulsed Corona Discharge to Water Surface

This study investigated the treatment of textile-dyeing wastewaterby using an electrical discharge technique (positive pulsed coronadischarge). The high-voltage electrode was placed above the surfaceof the wastewater while the ground electrode was submerged in thewastewater. The electrical discharge starting at the tip of the highvoltage electrode propagated toward the surface of the wastewater,producing various oxidative radicals and ozone. Oxygen was used asthe working gas instead of air to prevent nitrogen oxides fromforming. The simulated wastewater was made up with amaranth, whichis a kind of azo dye. The results obtained showed that thechromaticity of the wastewater was almost completely removed withinan hour. The ultraviolet/visible spectra of the wastewater treatedby the electrical discharge revealed that the total hydrocarbonlevel also decreased significantly.

Petroleum Hydrocarbons Accumulation Potential of Shellfishes from Littoral Waters of the Bight of Bonny, Niger Delta, Nigeria

Total hydrocarbons concentration in four commercially available shellfishes (Ocypoda africanus, Macura reptantia, Procambarus clarkii and Penaeus notialis) from coastal waters of the Niger Delta region of Nigeria were investigated between June 2003 and February 2004 using standard methods. Levels of total hydrocarbons varied significantly depending on biota species, feeding habit and season. The seasonal mean concentrations reported were: 3.98±0.69, 7.95±1.18, 2.24±0.39 and 5.85±0.57 µg g-1 dry weight for M. reptantia, O. africanus, P. clarkii and P. notialis respectively during the wet season. Enhanced concentrations recorded during the dry season were 7.81±2.32, 11.59±2.63, 6.16±2.12 and 9.69±1.90 µg g-1 dry weight for M. reptantia, O. africanus, P. clarkii and P. notialis respectively. The results obtained indicated seasonal variations which might have been associated with an incidental crude oil spill recorded during the investigation. In general, O. africanus showed higher levels of total hydrocarbons than other species investigated. However, biota species demonstrated hydrocarbon bioaccumulation potential. Regression between the monthly concentrations of total hydrocarbons in each of the biospecimens with the levels in the surface water and sediments indicated statistically significant (p<0.05) relationships. Moreover, comparison of the seasonal mean concentrations using paired sample t-test at 95% confidence level indicated that the concentrations between the dry and wet seasons were statistically significant.

Determination of total hydrocarbons levels in some marine organisms from some towns within the Rivers State of Nigeria

The total hydrocarbon (THC) content of three marine organisms; Periwinkles ( Pachyelina aurita ), mussels ( Mylitus edulis ) and mangrove Oysters ( Cassostrea gasar ) from polluted and unpolluted (i.e. control) sampling stations in parts of the Niger Delta area has been assessed. Statistical results revealed that the THC levels in periwinkles, mussels and mangrove oysters in polluted areas vary significantly at 95% confidence level from those from the control station. The results also show that the ability to accumulate total hydrocarbons varies with each organism investigated. Oysters were observed to accumulate the highest concentration of THC while periwinkles were the least. Journal of Applied Sciences and Environmental Management Vol. 9(3) 2005: 59-61

Assessment of marine pollution in Izmir Bay: Nutrient, heavy metal and total hydrocarbon concentrations

Izmir Bay (western Turkey) is one of the great natural bays of the Mediterranean. Izmir is an important industrial and commercial centre and a cultural focal point. The main industries in the region include food processing, oil, soap and paint production, chemical industries, paper and pulp factories, textile industries and metal processing. The mean concentrations showed ranges of 0.01–0.19 and 0.01–10 μM for phosphate, 0.10–1.8 and 0.12–27 μM for nitrate+nitrite, and 0.30–5.8 and 0.43–39 μM for silicate in the outer and middle–inner bays, respectively. The TNOx/PO4 ratio is significantly lower than the Redfield's ratio and nitrogen is the limiting element in the middle–inner bays. Diatoms and dinoflagellates were observed all year around in the bay and are normally nitrogen limited.Metal concentrations ranged between Hg: 0.05–1.3, Cd: 0.005–0.82, Pb: 14–113 and Cr: 29–316 μg g−1 in the sediments. The results showed significant enrichments during sampling periods from Inner Bay. Outer and middle bays show low levels of heavy metal enrichments except estuary of Gediz River. The concentrations of Hg, Cd and Pb in the outer bay were generally similar to the background levels from the Mediterranean. The levels gradually decreased over the sampling period. Total hydrocarbons concentrations range from 427 to 7800 ng g−1 of sediments. The highest total hydrocarbon levels were found in the inner bay due to the anthropogenic activities, mainly combustion processes of traffic and industrial activities.The concentrations of heavy metals found in fish varied for Hg: 4.5–520, Cd: 0.10–10 and Pb: 0.10–491 μg kg−1 in Izmir Bay. There was no significant seasonal variation in metal concentrations. An increase in Hg concentration with increasing length was noted for Mullus barbatus. A person can consume more than 2, 133 and 20 meals per week of fish in human diet would represent the tolerable weekly intake of mercury, cadmium and lead, respectively, in Izmir Bay. Heavy metal levels were lower than the results in fish tissues reported from polluted areas of the Mediterranean Sea.

Phytoremediation Innovative Technology (Series 2): A Short-term Comparative Analysis of Enhanced Biodegradation of Crude Oil in the Soil by Macrophytic Nodulation

A short term comparative ecological study of the use of two agro-forestry species, Leucaena leucocephala , Lam De. Wit and Bauhinia monandra , Kurz, in bioremediation of oil polluted environment was carried out, focusing on the evaluation and enhancing potential of the macrophytic species for degradation of hydrocarbon (crude oil) in the soil relative to their nodulation efficacy. Results show that L. leucocephala had nodules with levels ranging between 1.40 ± 1.40 to 11.60 ± 2.20 plant -1 and relative to various pollution levels and 15.10 ± 6.10 plant -1 in the control condition. Though L. leucocephala experienced pollution depression upon time lag in nodulation, the depression was directly proportional to the intensities of pollution. Bauhinia monandra had none at the end of the experiment both in the polluted and controlled conditions. Total hydrocarbon level following treatment of the soil by L. leucocephala and B. monadra has been deduced in relation to post-pollution concentration, disappearance and net % loss on such treated soil environment. A comparatively high value of 60% total loss of crude oil was indicated in L. leucocephala treated soil. This shows that natural biodegradation could be a major and ultimate mechanism for elimination of oil in terrestrial environment. The highest total % loss of crude oil was recorded in Leucaena leucocephala than Bauhinia monandra treated soil. Leucaena leucocephala showed an enhanced performance than Bauhinia monandra at the end of the study. Leucaena leucocephala was thus considered more ideal and more promising for remediation work than B.monandra . Keywords : Leucaena leucocephala, Bauhinia monandra , bioremediation, crude oil, nodulation Global Journal of Environmental Sciences Vol.4(1) 2005: 11-18

Measurement and Control of Airborne Molecular Contamination during Wafer Storage and Transport

A method was developed to measure total hydrocarbons (THCs) to 1 part-per-trillion (ppt) concentration levels using gas chromatography. This method was applied to measuring THCs in a front opening universal pod (FOUP) under static and purge conditions. XCDA® purge gas was used for this experiment. XCDA gas is clean dry air (CDA) purified with Aeronex® purification technology to remove moisture to less than 1 part-per-billion (ppb) and hydrocarbons, sulfur, and siloxane contaminants to less than 1ppt. The experiment reveals that a FOUP's environment contains ppb levels of THCs under static conditions and ppt concentration levels of THCs under purge conditions. This test demonstrates that ppt purity gas can be delivered to and maintained in a FOUP. Finally, a silicon wafer is exposed to a FOUP environment under static and purge conditions. Desorption studies show that hydrocarbon contamination on the wafer is reduced under purge conditions.

Evaluation of Total Hydrocarbon (THC) levels in oil polluted coastal areas of South Eastern Nigeria

Analysis of water, sediment and biota for total hydrocarbon (THC) levels five months after the Mobil oil spillage in the coastal areas of Cross River State, South Eastern Nigeria, was carried out. THC levels in water, sediment and biota samples were determined by colorimetric method after extraction with distilled n-hexane. Result showed elevated THC mean levels in water (149+81.11 mg/l), sediment (339.2 + 245.7 mg/kg) and biota (198.9 + 50.08 mg/kg), indicating a polluted environment. THC levels in water at all sampling locations were above 10mg/l being the maximum recommended limit of FEPA. In sediment and biota, THC values exceeding 100mg/kg and 25mg/kg, respectively, were observed, indicating that sediment and biota were highly impacted. THC levels in water correlated significantly (r = 0.632) with THC levels in the sediment (P = 0.05). Bioconcentration factors (BCFs) in 70% of the water samples were higher than unity. Although there was low BCF in about 70% of sediment samples, BCF in water significantly correlated (r = 0.689) with BCF in sediment (P = 0.05), indicating that the more the THC levels in the water column in relation to sediment, the more the biota were impacted. Key Words: Oil spillage, Total hydrocarbon, Bioconcentration factor, Polluted environment, Coastal Areas. [Global Jnl Environ Sci Vol.2(1) 2003: 1-9]

Effect of waste engine oil on phytoplankton of the Calabar River Estuary, Nigeria

The effect of waste lubrication oil on phytoplankton of the Calabar River Estuary has been examined under static conditions in the laboratory. Significant growth inhibitions and growth pattern alterations as well as susceptibility to bacterial attack were observed in the dominant diatom species- Actinocyclus and Aulocadiscus species during a 5 day exposure to concentrations of the oil ranging from 14.5 to 58 ppm. Oil treatment also resulted in growth enhancements in nanoflagellate population. Considering the importance of diatoms to organic carbon and oxygen supply in the Calabar River and associated Cross River Estuary, their destruction by oil and/succession by flagellates will result in negative consequences for fisheries and overall ecology of the system. The high toxicity of the waste oil even at low concentrations of total hydrocarbons calls for a re-appraisal of the permissible levels of total hydrocarbons in Nigerian inland waters currently put at 10 ppm. Key Words: Waste lubricating oil, Phytoplankton, toxicity, Calabar River Estuary. [Global Jnl Environ Sci Vol.2(2) 2003: 112-117]

Hydrocarbon pollution fixed to combined sewer sediment: a case study in Paris

Over a period of two years (2000–2001), sediment samples were extracted from 40 silt traps (STs) spread through the combined sewer system of Paris. All sediment samples were analysed for physico-chemical parameters (pH, organic matter content, grain size distribution), with total hydrocarbons (THs) and 16 polycyclic aromatic hydrocarbons (PAHs) selected from the priority list of the US-EPA. The two main objectives of the study were (1) to determine the hydrocarbon contamination levels in the sediments of the Paris combined sewer system and (2) to investigate the PAH fingerprints in order to assess their spatial variability and to elucidate the PAH origins. The results show that there is some important inter-site and intra-site variations in hydrocarbon contents. Despite this variability, TH and PAH contamination levels (50th percentile) in the Parisian sewer sediment are estimated at 530 and 18 μg g −1, respectively. The investigation of the aromatic compound distributions in all of the 40 STs has underlined that there is, at the Paris sewer system scale, a homogeneous PAH background pollution. Moreover, the study of the PAH fingerprints, using specific ratios, suggests the predominance of a pyrolytic origin for those PAHs fixed to the sewer sediment.

Benzene and total hydrocarbon exposures in the upstream petroleum oil and gas industry.

Occupational exposures to benzene and total hydrocarbons (THC) in the Canadian upstream petroleum industry are described in this article. A total of 1547 air samples taken by 5 oil companies in various sectors (i.e., conventional oil/gas, conventional gas, heavy oil processing, drilling and pipelines) were evaluated and summarized. The data includes personal long- and short-term samples and area long-term samples. The percentage of samples over the occupational exposure limit (OEL) of 3.2 mg/m3 or one part per million for benzene, for personal long-term samples ranges from 0 to 0.7% in the different sectors, and area long-term samples range from 0 to 13%. For short-term personal samples, the exceedance for benzene is at 5% with respect to the OEL of 16 mg/m3 or five parts per million in the conventional gas sector and none in the remaining sectors. THC levels were not available for all sectors and had limited data points in others. The percentage exceedance of the OEL of 280 mg/m3 or 100 parts per million for THC as gasoline ranged from 0 to 2.6% for personal long-term samples. It is recommended that certain operations such as glycol dehydrators be carefully monitored and that a task-based monitoring program be included along with the traditional long- and short-term personal exposure sampling.

Hydrocarbon Pollution in the Sediment of Some Malaysian Coastal Areas

A study was carried out at some selected coastal areas of Malaysia to determine the present status of hydrocarbon pollution. Five sites were chosen and these include Pulau Langkawi and Pulau Ketam in the west coast, Tanjung Piai in the south, and Pulau Tioman and Kemaman in the east coast of Peninsular Malaysia. The levels of total hydrocarbon in the sediments are found to vary from 18.2 to 847.4 mg kg-1 with sediments from Pulau Langkawi and Tanjung Piai recorded the highest values (691.2 to 847.4 mg kg-1) while Kemaman and Pulau Ketam recorded the lowest values (18.2 to 59.8 mg kg-1). It was noted that these values are related not only to possible sources of hydrocarbon but also to the physical characteristics of the sediments analysed. Sandy sediment generally contains less hydrocarbon than clayey sediment. Further analyses of the sediment extracts indicate that the sources of the hydrocarbon pollution are predominantly petrogenic with significant contribution from biogenic hydrocarbon.

Aliphatic hydrocarbons and linear alkylbenzenes in zooplankton from the Gulf of Trieste

It has been shown that linear alkylbenzenes (LABs) and aliphatic hydrocarbons are present in zooplankton in the Gulf of Trieste. Samples were collected in December of 1990, May and August of 1991. The total hydrocarbon levels for August were higher than those for December and May. This may be explained by high concentrations of biogenic hydrocarbons in this period. Odd and even n-alkane distribution in analyzed samples shows a partial contamination by fossil hydrocarbons. Among various isomers of linear alkylbenzenes, the ones isolated in the greatest quantities were generally those with the largest linear chain. We also identified several tetrapropylene alkylbenzenes isomers (TABs), which may still be used for sulfonate detergents in some countries.