In-situ burning of oil in coastal marshes. 2. Oil spill cleanup efficiency as a function of oil type, marsh type, and water depth

In-situ burning of spilled oil, which receives considerable attention in marine conditions, could be an effective way to cleanup wetland oil spills. An experimental in-situ burn was conducted to study the effects of oil type, marsh type, and water depth on oil chemistry and oil removal efficiency from the water surface and sediment. In-situ burning decreased the totaltargeted alkanes and total targeted polycyclic aromatic hydrocarbons (PAHs) in the burn residues as compared to the pre-burn diesel and crude oils. Removal was even more effective for short-chain alkanes and low ring-number PAHs. Removal efficiencies for alkanes and PAHs were >98% in terms of mass balance although concentrations of some long-chain alkanes and high ring-number PAHs increased in the burn residue as compared to the pre-burn oils. Thus, in-situ burning potentially prevents floating oil from drifting into and contaminating adjacent habitats and penetrating the sediment. In addition, in-situ burning significantly removed diesel oil that had penetrated the sediment for all water depths. Furthermore, in-situ burning at a water depth 2 cm below the soil surface significantly removed crude oil that had penetrated the sediment. As a result, in-situ burning may reduce the long-term impacts of oil on benthic organisms.     

Salt marsh recovery and oil spill remediation after in-situ burning: effects of water depth and burn duration

Effects of water depth, burn duration, and diesel fuel concentration on the relationship between recovery of marsh vegetation, soil temperature, and oil remediation during in-situ burning of oiled mesocosms were investigated. The water depth over the soil surface during in-situ burning was a major factor controlling recovery of the salt marsh grass, Spartina alterniflora. Ten centimeters of water overlying the soil surface was sufficient to protect the marsh soil from burn impacts with soil temperatures <37 degrees C and high plant survival rate. In contrast, a water table 10 cm below the soil surface resulted in mean soil temperatures > 100 degrees C at the 2-cm soil depth, which completely inhibited the post-burn recovery of S. alterniflora. Although poor plant recovery was also apparent in the treatments with 0 and 2 cm of water over the soil surface, this result was likely due to the chemical stress of the diesel fuel used to create the fire rather than the heat, per se, which never reached the estimated lethal temperature of 60 degrees C. In-situ burning effectively removed more than 95% of floating oil from the water surface. Thus, in-situ burning prevented the oil from potentially contaminating adjacent habitats. However, in-situ burning did not effectively remediate the oil that had penetrated the soil.     

Impacts and recovery of the Deepwater Horizon oil spill on vegetation structure and function of coastal salt marshes in the northern Gulf of Mexico

We investigated the impacts of the Deepwater Horizon (DWH) oil spill on two dominant coastal saltmarsh plants, Spartina alterniflora and Juncus roemerianus, in the northern Gulf of Mexico and the processes controlling differential species-effects and recovery. Seven months after the Macondo MC 252 oil made landfall along the shoreline salt marshes of northern Barataria Bay, Louisiana, concentrations of total petroleum hydrocarbons in the surface 2 cm of heavily oiled marsh soils were as high as 510 mg g(-1). Heavy oiling caused almost complete mortality of both species. However, moderate oiling impacted Spartina less severely than Juncus and, relative to the reference marshes, had no significant effect on Spartina while significantly lowering live aboveground biomass and stem density of Juncus. A greenhouse mesocosm study supported field results and indicated that S. alterniflora was much more tolerant to shoot oil coverage than J. roemerianus. Spartina recovered from as much as 100% oil coverage of shoots in 7 months; however, Juncus recovered to a much lesser extent. Soil-oiling significantly affected both species. Severe impacts of the Macondo oil to coastal marsh vegetation most likely resulted from oil exposure of the shoots and oil contact on/in the marsh soil, as well as repeated oiling events.     

Level and degradation of Deepwater Horizon spilled oil in coastal marsh sediments and pore-water

This research investigates the level and degradation of oil at ten selected Gulf saltmarsh sites months after the 2010 BP Macondo-1 well oil spill. Very high levels (10-28%) of organic carbon within the heavily oiled sediments are clearly distinguished from those in pristine sediments (<3%). Dissolved organic carbon in contaminated pore-waters, ranging up to hundreds of mg/kg, are 1 to 2 orders of magnitude higher than those at pristine sites. Heavily oiled sediments are characterized by very high sulfide concentrations (up to 80 mg/kg) and abundance of sulfate reducing bacteria. Geochemical biomarkers and stable carbon isotope analyses fingerprint the presence of oils in sediments. Ratios of selected parameters calculated from the gas chromatograph spectra are in a remarkable narrow range among spilled oils and initial BP crude. At oiled sites dominated by C(4) plants, δ(13)C values of sediments (-20.8 ± 2.0‰) have been shifted significantly lower compared to marsh plants (-14.8 ± 0.6‰) due to the inflow of isotopically lighter oil (-27 ± 0.2‰). Our results show that (1) lighter compounds of oil are quickly degraded by microbes while the heavier fractions of oil still remain and (2) higher inputs of organic matter from the oil spill enhance the key microbial processes associated with sulfate reducing bacteria.     

Modeling the boundaries of growth of Salmonella Typhimurium in broth as a function of temperature, water activity, and pH

The growth limits of a mixture of five strains of Salmonella Typhimurium in tryptic soy broth were examined at different environmental conditions. The response of the pathogen was monitored in a total of 350 combination treatments of temperature (10 to 35 degrees C), pH (3.76 to 6.44), and water activity (aw, 0.913 to 0.990) for 62 days. No growth/growth (turbidity) data were modeled by logistic polynomial regression. The concordance index of the logistic model was 99.8%, indicating a good fit to the observed data. The minimum pH and aw values that permitted growth were 3.94 and 0.942, respectively, and occurred in the temperature range of 25 to 35 degrees C. At temperatures below this range, the minimum pH and aw allowing growth increased as the temperature decreased. The results showed an abrupt change in the probability of growth close to the boundary with minor changes of the environmental factors. The probabilities predicted by the model were compared with published data on the actual response of Salmonella Typhimurium or other salmonellae serotypes in 50 cases of food products, including salad dressing, mayonnaise, meat, cheese, vegetables, and fruits. The model predicted successfully the response of the pathogen in 90% of the tested cases. The results of the study indicated that the developed model predicts satisfactorily the growth/no growth interface of Salmonella Typhimurium in foods and can provide useful quantitative data for the development of safer food products and processes.     

Distribution of almond polyphenols in blanch water and skins as a function of blanching time and temperature

The distribution of polyphenols in blanched almond skins and blanch water, as a function of time and temperature, was quantified using negative ion electrospray time-of-flight mass spectrometry (ESI TOF MS). Almonds were blanched in 25° (RT) and 100 °C (HW) water for up to 10 min. At 10 min, ∼30% (25°) and 90% (100 °C) of the polyphenols quantified had leached from the skins into the blanch water. Many of the compounds precipitated from the blanch water due to limited water solubility, as evidenced by a logarithmic fit to kinetic data (1st order kinetics). The rate of procyanidin degradation into smaller polymeric units (e.g., catechin and epicatechin) also increased as a function of time and temperature. Finally, hydration in RT water increased the extraction efficiency of phenolics by 25%. This work shows that the blanch water, in particular the 100 °C blanch water, was rich in polyphenols and supports exploration of alternative uses for blanch water.     

Trace elements and radionuclides in palm oil,soil, water,and leaves from oil palm plantations: A review

Oil palm (Elaeisguineensis) is one of the most productive oil producing plant in the world. Crude palm oil is composed of triglycerides supplying the world's need of edible oils and fats. Palm oil also provides essential elements and antioxidants that are potential mediators of cellular functions. Experimental studies have demonstrated the toxicity of the accumulation of significant amounts of nonessential trace elements and radionuclides in palm oil that affects the health of consumers. It has been reported that uptake of trace elements and radionuclides from the oil palm tree may be from water and soil on the palm plantations. In the present review, an attempt was made to revise and access knowledge on the presence of some selected trace elements and radionuclides in palm oil, soil, water, and leaves from oil palm plantations based on the available facts and data. Existing reports show that the presence of nonessential trace elements and radionuclides in palm oil may be from natural or anthropogenic sources in the environment. However, the available literature is limited and further research need to be channeled to the investigation of trace elements and radionuclides in soil, water, leaves, and palm oil from oil palm plantations around the globe.     

Maximizing the production of γ-linolenic acid in Mortierella ramanniana var. ramanniana as a function of pH,temperature and carbon source,nitrogen source,metal ions and oil supplementation

A locally isolated (Perryvale, Alta., Canada) fungal genus, Mortierella ramanniana var. ramanniana, was evaluated as a potential industrial producer of γ-linolenic acid (GLA). Six growth variables (pH, temperature, carbon source, nitrogen source, and metal ions and oil supplementation) were systematically manipulated. The results indicated that the GLA production for this particular strain, could be maximized by using a basal growth medium consisting of 5% dextrose and 1% yeast extract, supplemented with 5 mg/L Mn²⁺ with incubation at 20 °C. The lipid yield under optimum conditions was 54.2% of the total dry biomass and consisted of 84.3% unsaturated fatty acids. The yield of GLA per gram biomass represented 13.3% of the total lipid content, slightly higher than that of the typical evening primrose oil GLA yield. The study establishes this variety as an effective intermediate fungal source of GLA.     

Olive oil composition as a function of nitrogen,phosphorus and potassium plant nutrition

BACKGROUND: Macronutrients play fundamental roles in processes affecting olive oil productivity and are expected to influence oil composition. A necessary step in optimal nutrient application management for olives is an understanding of the relationship between olive tree nutritional status and oil quality parameters. We studied the independent effects of N, P and K concentrations in irrigation solution on the oil quality of ‘Barnea’ olives by applying a wide range of macronutrient concentrations under highly controlled conditions. RESULTS: Oil composition was significantly influenced by P and N levels, while K levels had only a minor effect. Unsaturation levels were unaffected by the treatments but, within the unsaturated fatty acids, the levels of PUFA increased compared to those of MUFA. Specifically, levels of the MUFA C18:1, polyphenol content and peroxide values decreased while levels of the PUFA C18:3 increased in response to higher doses of N and P. CONCLUSION: Decreased MUFA and polyphenol levels coupled with increased omega‐3 levels demonstrated a potential negative influence on oil profile alongside increased nutritional benefits. The sum effects on oil yield and composition should be considered in designing of nutrient application management strategies for olive orchards. Copyright © 2009 Society of Chemical Industry     

Milk pH as a function of CO2 concentration, temperature, and pressure in a heat exchanger

Raw skim milk, with or without added CO2, was heated, held, and cooled in a small pilot-scale tubular heat exchanger (372 ml/min). The experiment was replicated twice, and, for each replication, milk was first carbonated at 0 to 1 degree C to contain 0 (control), 600, 1200, 1800, and 2400 ppm added CO2 using a continuous carbonation unit. After storage at 0 to 1 degree C, portions of milk at each CO2 concentration were heated to 40, 56, 72, and 80 degrees C, held at the desired temperature for 30 s (except 80 degrees C, holding 20 s) and cooled to 0 to 1 degree C. At each temperature, five pressures were applied: 69, 138, 207, 276, and 345 kPa. Pressure was controlled with a needle valve at the heat exchanger exit. Both the pressure gauge and pH probe were inline at the end of the holding section. Milk pH during heating depended on CO2 concentration, temperature, and pressure. During heating of milk without added CO2, pH decreased linearly as a function of increasing temperature but was independent of pressure. In general, the pH of milk with added CO2 decreased with increasing CO2 concentration and pressure. For milk with added CO2, at a fixed CO2 concentration, the effect of pressure on pH decrease was greater at a higher temperature. At a fixed temperature, the effect of pressure on pH decrease was greater for milk with a higher CO2 concentration. Thermal death of bacteria during pasteurization of milk without added CO2 is probably due not only to temperature but also to the decrease in pH that occurs during the process. Increasing milk CO2 concentration and pressure decreases the milk pH even further during heating and may further enhance the microbial killing power of pasteurization.     

Influence of different mulch materials on soil temperature,soil water content and yield of three cassava cultivars

In a study with three cassava (Manihot esculenta Crantz) cultivars (Local, TMS4(2)1425 and TMS30572) grown under straw, black polythene and white polythene mulches the fresh tuber yield and yield components were greater than for those grown on bare (control) plots, although the magnitude of increase was cultivar dependent. The order of response was white polythene > straw > black polythene > bare (control). The yield differences were caused by the effects of the mulches on the temperature and water content of the soil surface. Maximum daily soil temperature was lowest on the straw plots (32·5°C), about equal on the bare and white polythene treatments (38·6°C vs 39·8°C) and highest on the black polythene plots (45·0°C). In 1986 the soil moisture reserve was depleted by 84%, 46%, 29% and 24% on the bare, straw, black polythene and white polythene plots within a 60-day period following the last rain, suggesting that it was soil temperature rather than soil moisture which accounted for the large yield differences under black and white polythene.     

Effect of oil type, temperature and time on moisture properties of hot oil-treated wood

This paper focuses on the moisture properties of wood treated in palm oil-, soy oil- and slack wax for different processing times and temperatures. Also, the relative importance of oil uptake and thermal modification on the wood moisture properties is investigated. Slack wax was better than palm oil or soy oil in improving the moisture performance of thermally treated wood, and treatment at 220 °C was superior to treatment at 200 °C, with 4 h being generally better than 2 h treatment. Water absorption in samples treated with wax at 100 °C or 160 °C was similar to that in samples treated at high temperatures while improved anti-shrink efficiencies (ASE) and lower hygroscopicities occurred only for the high temperature treatments. Chloroform extracted samples treated at high temperature with palm oil or soy oil had relatively similar hygroscopicity and ASE properties compared to unextracted samples, but had greatly increased water absorption properties. These results confirm that chemical reactions in wood resulting from the heat treatment account for the main improvements of wood properties in reduced hygroscopicity and improved dimensional stability, while the oil absorbed by wood reduces the rate of water absorption.     

Oxidative stability of potato chips: effect of frying oil type,temperature and antioxidants

The effect of type of frying oil and temperature on the oxidative stability of potato chips during storage was studied. Cottonseed oil, soybean oil, olive kernel oil and palmolein were used as frying media. The chips were packaged in metallized cellophane bags and incubated at 63 °C. At definite time intervals the absorbed oil was extracted and analyzed for peroxide value, Totox number and conjugated diene content. Olive kernel oil and palmolein absorbed into the chips showed better stability, whereas soybean oil presented the higher oxidation rate. Frying temperature (170, 180 or 190 °C) did not affect the oxidation rate during storage, with the exception of conjugated diene formation which was greater for chips fried at 190 °C. Ground oregano or oregano extract, obtained by petroleum ether extraction, were added to the chips as antioxidants. Both retarded significantly the oxidation rate of the oil absorbed into the chips, with results comparable to tertiary butylhydroquinone (TBHQ) during storage at 63 °C for 7 days; however TBHQ proved significantly more effective after that time. © 1999 Society of Chemical Industry     

Sporulation boundaries and spore formation kinetics of Bacillus spp. as a function of temperature, pH and a(w)

Sporulation niches in the food chain are considered as a source of hazard and are not clearly identified. Determining the sporulation environmental boundaries could contribute to identify potential sporulation niches. Spore formation was determined in a Sporulation Mineral Buffer. The effect of incubation temperature, pH and water activity on time to one spore per mL, maximum sporulation rate and final spore concentration was investigated for a Bacillus weihenstephanensis and a Bacillus licheniformis strain.     

Effects of heat-processing regime, pH, water activity and their interactions on the behaviour of Listeria monocytogenes in ground pork. Modelling the boundary of the growth/no-growth areas as a function of pH, water activity and temperature

The influence of four heat‐processing regimes and a storage phase on the behaviour of Listeria monocytogenes in ground pork was studied. The effects of pH and water activity (a_w) were also tested. During the heat process phase, a_w, the heat‐processing regime and its interactions with pH or a_w, had a significant effect on the behaviour of L. monocytogenes. During the storage phase, all parameters tested and their interactions had significant effects. Nevertheless, the area in which the growth of L. monocytogenes was observed at the end of the experiment was not influenced by the heat‐processing regime tested. On the contrary, pH, a_w and their interactions had significant effects on Listeria behaviour. The boundary of the growth area delimited by environmental conditions where growth was higher than 1.0 Log CFU g^?1 from those where growth was lower than this limit was correctly predicted by Augustin's model.     

Thermal inactivation of poliovirus type 1 in water, milk and yoghurt

Loss of infectivity of poliovirus type 1, strain Sabin, during heating, freezing, and storage in water, milk and yoghurt was determined by plaque-titration in Vero cell cultures. The heating experiments simulated the conditions arising during the processing of milk and yoghurt, for example high-temperature heating (95 degrees C, 15 and 30 s), short-time pasteurization (72 degrees C, 15 and 30 s), long-time pasteurization (62 degrees C, 30 min), and yoghurt-fermentation (42 degrees C, 30 min and 180 min). Only high-temperature heating, long-time pasteurization and short-time pasteurization for 30 s proved to be reliable methods of inactivating polioviruses present in water, milk and yoghurt completely. Short-time pasteurization for 15 s and the conditions of yoghurt-fermentation failed to cause complete inactivation of polioviruses. Additionally, polioviruses mixed in milk or yoghurt withstood these procedures with significantly lower reductions of infectivity than in water. Heating at 55 degrees C for 30 min resulted in complete inactivation of polioviruses, regardless of the suspending medium. The infectivity of polioviruses is scarcely affected by freezing (-20 degrees C, 30 min) and storage (24 days) at low temperatures (4 degrees C) and high humidity (a(w) = 0.99).     

Power generation in fed-batch microbial fuel cells as a function of ionic strength, temperature, and reactor configuration

Power density, electrode potential, coulombic efficiency, and energy recovery in single-chamber microbial fuel cells (MFCs) were examined as a function of solution ionic strength, electrode spacing and composition, and temperature. Increasing the solution ionic strength from 100 to 400 mM by adding NaCl increased power output from 720 to 1330 mW/m2. Power generation was also increased from 720 to 1210 mW/m2 by decreasing the distance between the anode and cathode from 4to 2 cm. The power increases due to ionic strength and electrode spacing resulted from a decrease in the internal resistance. Power output was also increased by 68% by replacing the cathode (purchased from a manufacturer) with our own carbon cloth cathode containing the same Pt loading. The performance of conventional anaerobic treatment processes, such as anaerobic digestion, are adversely affected by temperatures below 30 degrees C. However, decreasing the temperature from 32 to 20 degrees C reduced power output by only 9%, primarily as a result of the reduction of the cathode potential. Coulombic efficiencies and overall energy recovery varied as a function of operating conditions, but were a maximum of 61.4 and 15.1% (operating conditions of 32 degrees C, carbon paper cathode, and the solution amended with 300 mM NaCl). These results, which demonstrate that power densities can be increased to over 1 W/m2 by changing the operating conditions or electrode spacing, should lead to further improvements in power generation and energy recovery in single-chamber, air-cathode MFCs.