Importance of Different Volatile Petroleum Hydrocarbon Fractions in Human Health Risk Assessment

Soil vapor data for benzene and four aliphatic and aromatic hydrocarbon fractions from five volatile petroleum hydrocarbon (VPH)-contaminated sites in western Canada were used together with the Canadian Council of Ministers of the Environment (CCME) Canada-Wide Standard for petroleum hydrocarbons to investigate the relative importance of benzene and the different fractions in human health risk assessment. VPH concentrations in soil vapor samples ranged from 4.0 to 4200?mg/m³, of which 0 to 4.6% was BTEX and 90 to 95% was hydrocarbons of the C_5–8 aliphatic fraction. VPH inhalation exposure by an adult receptor in a hypothetical, commercial building was modelled deterministically assuming 16- and 70 year occupational tenures. The magnitude of hazard quotients varied widely between sites, but their hydrocarbon fraction signatures were consistent, and characterized by higher hazard quotients in the C_5–8 and C_9–10 aliphatic and C_9–10 aromatic fractions relative to benzene and the TEX aromatic fraction. This work has shown that the C_5– and C_9–10 aliphatic fractions yield greater relative risk than the commonlyregulated TEX compounds, and that benzene becomes the primary chemical of potential concern only when an occupational tenure approaching 70 years is assumed.     

Leptin Response to Glucocorticoid Occurs at Physiological Doses and Is Abolished by Fasting

Objective: To examine the effects of graded doses of hydrocortisone (HC) on leptin secretion, and determine the effect of fasting. Research Methods and Procedures: This was a randomized, placebo‐controlled, crossover study, with a 1‐week “washout” period between interventions. Eight healthy subjects [age = 36 ± 2.3 years (±SE), body mass index = 31.5 ± 1.6 kg/m²] completed the dose‐response study in which an intravenous infusion of saline (placebo) or HC (30 or 100 mg) was administered for 24 hours. Four healthy subjects (age = 35.2 ± 3.0 years, body mass index = 27.1 ± 2.1 kg/m²) completed the fasting study, which entailed continuous infusion of saline, HC (300 mg/24 hours) in the fed state, or HC (300 mg/24 hours) with total caloric deprivation for 24 hours. Blood sampling was performed every 1 to 2 hours for measurement of leptin, cortisol, insulin, and glucose levels. Results: Peak hyperleptinemia occurred after 16 hours of HC infusion; peak/baseline leptin levels were 129% (placebo), 140% (30 mg of HC for 24 hours, p = 0.05), and 185% (100 mg of HC for 24 hours, p < 0.01). During infusion of HC (300 mg/24 hours or placebo), the peak/baseline plasma leptin levels were 16.1 ± 5.8/12.8 ± 5.9 ng/mL (placebo with food, 126%), 14.6 ± 6.0/12.5 ± 6.5 ng/mL (HC fasting, 117%), and 32.5 ± 12.5/12.0 ± 8.4 ng/mL (HC with food, 271%, p < 0.001). Discussion: Leptin secretory responses occur at physiological doses of HC, are obliterated by fasting, and thus may be of metabolic significance.     

Residues of Aliphatic and Polycyclic Aromatic Hydrocarbons in Some Fish Species of Lake Temsah,Ismailia, Egypt: An Analytical Search for Hydrocarbon Sources and Exposure Bioindicators

Residues of aliphatic and polycyclic aromatic hydrocarbons (PAHs) were monitored in some fish species collected from Temsah Lake, near Ismailia, Egypt. Fish were selected to represent different feeding habits and ecological niches in the lake's ecosystem. Fish samples were extracted using organic solvents, and residues of aliphatic and PAHs were separated using column chromatography and detected using gas liquid chromatography. Fish species were Clupea sirm, Mugil sehli, Mugil capito, Morone labrax, and Sciasna sp. Clupea sirm, a surface feeder fish had the highest concentration of aliphatic hydrocarbons, 320 ± 54 ng g^?1, while Morone labrax, a predatory fish that live in the water column, had the highest concentration of PAHs, 315.87 ± 46 ng g^?1. Even-number aliphatic hydrocarbons were more frequently detected in all fish species in comparison to odd-number aliphatic hydrocarbons, suggesting a petrogenic origin of these compounds. Meanwhile, the pattern of PAHs detected in the present study suggested that they originate from atmospheric deposition rather than land-based runoff. Morone labrax fish and Clupea sirm fish were the most suitable candidate bioindicators of exposure to aliphatic hydrocarbons and PAHs through fish consumption of the five fish species examined in this study.     

Aerobic degradation of a hydrocarbon mixture in natural uncontaminated potting soil by indigenous microorganisms at 20 °C and 6 °C

A hydrocarbon mixture containing p-xylene, naphthalene, Br-naphthalene and straight aliphatic hydrocarbons (C₁₄ to C₁₇) was aerobically degraded without lag phase by a natural uncontaminated potting soil at 20 °C and 6 °C. Starting concentrations were approximately 46 ppm for the aromatic and 13 ppm for the aliphatic compounds. All aliphatic hydrocarbons were degraded within 5 days at 20 °C, to levels below detection (ppb levels) but only down to 10% of initial concentration at 6 °C. Naphthalene was degraded within 12 days at 20 °C and unaffected at 6 °C. At 20 °C p-xylene was degraded within 20 days, but no degradation occurred at 6 °C. Br-naphthalene was only removed down to 30% of initial concentration at 20 °C, with no significant effect at 6 °C. The biodegradation was monitored with head space solid-phase microextraction and gas chromatography–mass spectrometry. Received: 5 October 1998 / Received revision: 4 December 1998 / Accepted: 5 December 1998     

Co-Composting of Residual Fuel Contamination in Soil

A remediation program was designed and implemented at a site in southeastern Australia that had become contaminated with nonvolatile, n-alkane total petroleum hydrocarbons (TPH). The remediation was conducted in two stages. The excavation, validation and reinstatement of two contaminated areas on the site was first conducted, followed by development of a composting treatment process. The total volume of contaminated soil (i. e., TPH concentration >1000?mg/kg C₁₀?C₃₆) was ～4300?m³ with a concentration of 3100±1270?mg/kg. The soil was stockpiled into four windrows, on a compacted, bunded clay base. Approximately 35% (v/v) of raw materials (green tree waste, cow manure, gypsum, and nutrients) were added to initiate composting. The piles were kept moist during the summer months, but no other maintenance was conducted. Once the composting process was initiated, the windrows were sampled at 2 and 6 months. After 6 months treatment, the average TPH concentration (C₁₀?C₃₆) was 730?mg/kg (with a 95% CI of 1020?mg/kg), which met the relevant clean fill criteria applicable to the site. There were no other contaminants of significance in the treated soil compost and it posed no unacceptable risk to human health or the environment, allowing it to be used as fill at the site.     

Mycoremediation of oil contaminant by Pleurotus florida (P.Kumm) in liquid culture

This study investigated the potential functions of Pleurotus florida (an edible mushroom) in the biodegradation of gas oil at concentrations of 0 (control), 2.5, 5, and 10% (V: V) for 30 days. The gas oil increased dry weight and protein concentration in all treatments (by an average of 19.5 and 108%, respectively). Moreover, the pH, surface tension (ST), and interfacial tension (IFT) were reduced by the mushroom supplementation. The lowest surface tension (31.9 mN m⁻¹) and the highest biosurfactant production belonged to the 10% gas oil treatment (0.845 ± 0.03 mg mL⁻¹). The results demonstrated that the adsorption isotherm agreed well with the Langmuir isotherm. The maximum Langmuir adsorption capacity was calculated at 0.743 mg g⁻¹ wet biomass of P. florida. The fungal supplementation efficiently remedied the total petroleum hydrocarbons (TPHs) by an average of 55% after 30 days. Gas chromatography (GC) analysis revealed that P. florida effectively detoxified C₁₃–C₂₈ hydrocarbons, Pristane, and Phytane, implying its high mycoremediation function. The toxicity test showed that mycoremediation increased the germination by an average of 35.82% ± 8.89 after 30 days. Laccase activity increased significantly with increasing gas oil concentration in the treatments. The maximum laccase activity was obtained in the 10% gas oil treatment (142.25 ± 0.72 U L⁻¹). The presence of pollutants was also associated with induction in the tyrosinase activity when compared to the control. These results underline the high mycoremediation capacity of P. florida through the involvement of biosurfactants, laccase, and tyrosinase.     

Self-diffusion of water-soluble fullerene derivatives in mouse erythrocytes

Self-diffusion of water-soluble fullerene derivative (WSFD) C₆₀[S(CH₂)₃SO₃Na]₅H in mouse red blood cells (RBC) was characterized by ¹H pulsed field gradient NMR technique. It was found that a fraction of fullerene molecules (~13% of the fullerene derivative added in aqueous RBC suspension) shows a self-diffusion coefficient of (5.5 ± 0.8)·10⁻¹² m²/s, which is matching the coefficient of the lateral diffusion of lipids in the erythrocyte membrane (D_L = (5.4 ± 0.8)·10⁻¹² m²/s). This experimental finding evidences the absorption of the fullerene derivative by RBC. Fullerene derivative molecules are also absorbed by RBC ghosts and phosphatidylcholine liposomes as manifested in self-diffusion coefficients of (7.9 ± 1.2)·10⁻¹² m²/s and (7.7 ± 1.2)·10⁻¹² m²/s, which are also close to the lateral diffusion coefficients of (6.5 ± 1.0)·10⁻¹² m²/s and (8.5 ± 1.3)·10⁻¹² m²/s, respectively. The obtained results suggest that fullerene derivative molecules are, probably, fixed on the RBC surface. The average residence time of the fullerene derivative molecule on RBC was estimated as 440 ± 70 ms. Thus, the pulsed field gradient NMR was shown to be a versatile technique for investigation of the interactions of the fullerene derivatives with blood cells providing essential information, which can be projected on their behavior in-vivo after intravenous administration while screening as potential drug candidates.     

Petroleum-contaminated water treatment in a fluidized-bed bioreactor with immobilized Rhodococcus cells

Biotreatment of petroleum-contaminated water in a fluidized-bed bioreactor (FBB) is a relatively new and promising technology, which efficiency is strongly affected by the biocatalyst used. Our laboratory experiments involved biotreatment of the water contaminated with a synthetic petroleum mixture consisting of aliphatic and polyaromatic hydrocarbons (PAHs) using a continuous column bioreactor with recycle. Different type biocatalysts were tested, including Rhodococcus bacteria immobilized in hydrophobized carriers such as sawdust, poly(vinyl alcohol) cryogel (cryoPVA) and poly(acrylamide) cryogel (cryoPAAG). Biocatalyst abilities to oxidize petroleum hydrocarbons were evaluated using the Columbus Micro-Oxymax^® respirometer. The hydrophobized sawdust-supported biocatalyst demonstrated substantially higher metabolic activity than C₁₂-cryoPAAG-based biocatalyst due to larger number of immobilized Rhodococcus cells and, therefore, had benefits for application in FBBs. The obtained results showed that designed FBB process is successful, providing 70–100% removal of n-alkanes (C₁₀–C₁₉) and 66–70% removal of 2–3-ring PAHs from contaminated water after 2–3 weeks.     

Heterotrophic microorganisms and viruses in the water of the Gorky reservoir during a period of anomalously high water temperature

During the anomalously hot summer of 2010, the water temperature in the Gorky reservoir reached 27–33°C. Pronounced cyanobacterial blooms occurred in the limnetic part of the reservoir. The average values for bacterioplankton abundance (11.58 ± 1.25 × 10⁶ cell/mL), biomass (886 ± 96 mg/m³), and production [169 ± 32 mg C/(m³ day)] were twice as high as in the year with temperatures comparable to long-term average values. These parameters were higher in the limnetic part than in the river one. The abundance (4.86 ± 0.75 × 10³ cell/mL) and biomass (138 ± 9 mg/m³) of heterotrophic nanoflagellates were 2.3 and 1.7 times higher, respectively, than in years with regular temperature regimes. The average number of plank-tonic viral particles (N _v) in 2010 was 48.89 ± 9.54 × 10⁶ particles/mL, while virus-induced bacterial mortality (VMB) accounted for 26.9 ± 4.6% of the bacterial production. The N _v and VMB values in the limnetic part of the reservoir were, respectively, 1.5 and 1.8 times higher than in the river one.     

Powder properties and their influence on dry powder inhaler delivery of an antitubercular drug

The purpose of this study was to determine if aerosol delivery of drug loaded microparticles to lungs infected withMycobacterium tuberculosis may be achieved by predicting dispersion of dry powders through knowledge of particle surface properties. Particle sizes of rifampicin-loaded poly(lactide-co-glycolide) microparticles (R-PLGA), rifampicin alone, and lactose and maltodextrin carrier particles (bulk and 75-125-μm sieved fractions) were determined by electron microscopy for the projected area diameter (D_p) and laser diffraction for the volume diameter (D_v). Surface energies (Y) of R-PLGA, rifampicin alone, lactose, and maltodextrin were obtained by inverse phase gas chromatography, surface areas (S_a) by N₂ adsorption, and cohesive energy densities by calculation. Particle dispersion was evaluated (Andersen nonviable impactor) for 10% blends of R-PLGA and rifampicin alone with bulk and sieved fractions of the carriers. D_p for R-PLGA and rifampicin alone was 3.02 and 2.83 μm, respectively. D_v was 13±1 and 2±1 μm for R-PLGA and rifampicin alone, respectively, indicating that R-PLGA was more aggregated. This was evident in Y of 35±1 and 19±6 mJ/m² for R-PLGA and rifampicin alone. D_p for lactose and maltodextrin (sieved and bulk) was approximately 40 mm. Bulk maltodextrin (D_v=119±6 mm) was more aggregated than bulk lactose (D_v=54±2 mm). This was a result of the higher S_a for maltodextrin (0.54 m²/g) than for lactose (0.21 m²/g). The Y of bulk lactose and maltodextrin was 40±4 and 60±6 mJ/m² and of sieved lactose and maltodextrin was 39±1 and 50±1 mJ/m². Impaction studies yielded higher fine particle fractions of R-PLGA from sieved lactose, 13%±3%, than from sieved maltodextrin, 7%±1%, at 90 L/min. An expression, based on these data, is proposed as a predictor of drug dispersion from carrier particles. Delivery of dry powder formulations can be achieved by characterizing particle surfaces and predicting impact on dispersion.     

Constituents of Fusel Oils Obtained Through the Fermentation of Corn,Barley and Sweet Molasses

The components of the fusel oils obtained through the fermentation of corn, barley and sweet molasses were separated by fractional distillation and adsorption chromatography. Each of the components was analyzed by gas chromatography and infrared spectrometry. Newly isolated components were as follows: methyl heptenone, fatty acids having odd number of carbon atoms, acetic esters of higher aliphatic alcohols ranging from C₆ to C₁₁, benzyl alcohol, ethyl phenylacetate, phenylethyl propionate, acetophenone, limonene, and α-ionone. Moreover, an unknown ketone C₁₀H₁₆O were isolated from corn fusel oil, and trans-neroridol from sweet molass fusel oil.     

Characteristics of biosurfactant produced by Pseudomonas aeruginosa S6 isolated from oil-containing wastewater

A biosurfactant-producing strain S6 was isolated from oil-containing wastewater and identified as Pseudomonas aeruginosa based on physiological and biochemical tests together with 16S rDNA sequence analysis. Thin layer chromatography (TLC) and high-performance liquid chromatography electrospray ionization mass spectra (HPLC-ESI-MS) worked together to reveal that the strain S6 produced rhamnolipid biosurfactant. Mass spectrometry confirmed the presence of some major components in the rhamnolipid surfactant showing m/z of 675.8, 529.6, 503.3 and 475.4, which corresponded to RhaRhaC₁₀C_12:1, RhaC_12:1C₁₀, RhaC₁₀C₁₀ and RhaC₈C₁₀, respectively. The biosurfactant produced by strain S6 had the ability to decrease the surface tension of water from 72 to 33.9 mN m^?1, with the critical micelle concentration (CMC) of 50 mg L^?1. Emulsification experiment indicated that this biosurfactant effectively emulsified the crude petroleum and the measurements of surface tension demonstrated that the biosurfactant possessed stable surface activity at variable ranges of pH and salinity. The biosurfactant also exhibited good performance of phenanthrene solubilization with about 23 times higher solubility of phenanthrene in water than the control. Thus, this biosurfactant may have a potential for application in bioremediation of crude oil contamination.     

Hydrocarbon degradation by <Emphasis Type="Italic">Dietzia</Emphasis> sp. A14101 isolated from an oil reservoir model column

The hydrocarbon-degrading strain Dietzia sp. A14101 was isolated from an oil reservoir model column inoculated with oil-field bacteria. The column was continuously injected with nitrate (0.5 mM) from the start of water flooding, which lead to a gradual development of nitrate reduction in the column. Strain A14101 was able to utilize a range of aliphatic hydrocarbons as sole carbon and energy source during aerobic growth. Whole oil gas chromatography analysis of the crude oil phase from aerobic pure cultures showed that strain A14101 utilized the near complete range of aliphatic components and aromatic components toluene and xylene. Longer n-alkanes ≥C₁₇ were utilized simultaneously with the shorter C₁₀ and C₁₅. After 120 days aerobic incubation, the whole oil gas chromatography profile of the crude oil phase was similar to that of heavily biodegraded oils. Anaerobic degradation of hydrocarbons with nitrate was not observed. Nitrate reduction was, however, observed during anaerobic growth on propionate, which suggests that strain A14101 grows on fatty acids in the column rather than on hydrocarbons.     

Physiological Daily Inhalation Rates for Free-Living Individuals Aged 1 Month to 96 Years,Using Data from Doubly Labeled Water Measurements: A Proposal for Air Quality Criteria,Standard Calculations and Health Risk Assessment

Reported disappearance rates of oral doses of doubly labeled water (²H₂O and H₂ ¹⁸O) in urine, monitored by gas-isotope-ratio mass spectrometry for an aggregate period of over 30,000 days and completed with indirect calorimetry and nutritional balance measurements, have been used to determine physiological daily inhalation rates for 2210 individuals aged 3 weeks to 96 years. Rates in m³/kg-day for healthy normal-weight individuals (n = 1252) were higher by 6 to 21% compared to their overweight/obese counterparts (n = 679). Rates for healthy normal-weight males and females drop by about 66 to 75% within the course of a lifetime. Infants and children between the age of 3 weeks to less than 7 years inhale 1.6 to 4.3 times more air (0.395 ± 0.048 to 0.739 ± 0.071 m³/kg-day, mean ± S.D., n = 581) than adults aged 23 to 96 years (0.172 ± 0.037 to 0.247 ± 0.039 m³/kg-day, n = 388). The 99th percentile rate of 0.725 m³/kg-day based on measurements for boys aged 2.6 to less than 6 months is recommended for air quality criteria and standard calculation for non-carcinogenic compounds pertaining to individuals of any age or gender (normality confirmed using the Shapiro-Wilk test, p ≥ 0.05). This rate is 2.5-fold more protective than the daily inhalation estimate of 0.286 m³/kg-day published by the Federal Register in 1980 (i.e., 20 m³/day for a 70-kg adult). It ensures that very few newborns aged 1 month and younger, less than 1% of infants aged 2.6 to less than 6 months and of course no older individuals up to 96 years of age inhale more toxic chemicals than associated safe doses which are not anticipated to result in any adverse effects in humans, when air concentration reaches the resulting air quality criteria and standard values. This rate is also protective for underweight, overweight, and obese individuals. Finally, as far as newborns are concerned, a rate of 0.956 m³/kg-day based on the 99th percentile estimates is recommended for short-term criteria and standard calculations for toxic chemicals that yield adverse effects over instantaneous to short-term duration.     

Authigenic mineralization and detrital clay binding by freshwater biofilms: The Brahmani river,India

This study sought to understand the origin and fate of one of the bitumen mounds found on the bottom of Lake Baikal. These mounds are located at a depth of 900 m beneath oil spots detected on the surface of Lake Baikal (53° 18′24^″, 108° 23′20^″). The two mounds were sampled with a manipulator from a “MIR” deep-water manned submersible. Mature mound No. 8 was subjected to chemical and microbiological studies. Mound No. 3 was subjected only to chemical studies; we failed to perform microbiological analyses of this mound for logistic reasons. Oil spots collected from the water surface, samples of mound No. 3 and No. 8, were subjected to GC/MS analysis. The water contained aliphatic hydrocarbons with chains between C₈ and C₂₃, with the most abundant chain length being C₁₈. Mound No. 3 with the most abundant chain length being C₁₈ actively released oil droplets into the water. It contained 770 mg/g of C₁₃-C₃₂ n-alkanes, with a maximum at C₂₃ (160 mg/g). Mound No. 8 was inactive and contained 148 mg/g of aliphatic C₂₂-C₃₄ n-alkanes, with a maximum at C₂₅. Mound No. 8 also consisted of 3% inorganic matter, 48% unresolved complex mixture (UCM) and less than 1% other compounds (polyaromatic hydrocarbons, isoprenoids, carotenoids, and hopanes). The core of this sample used as inoculate, yielded Rhodococci when cultivated on oil as the only source of carbon. Cultivation of the sample on agar-containing Raymond inorganic medium with crude West Siberian oil as the only source of carbon revealed colonies of these bacteria, which all appeared identical. PCR was performed with DNA isolated from 5 colonies, using primers for 16S rRNA genes. Comparison of the sequences of the 5 PCR products over a length of 714 bp revealed that they were almost identical. Phylogenetic analysis of these homologous sequences showed that they were similar to the corresponding sequences of the genus Rhodococcus. Substrate demands, the morphology of the colonies, and SEM and TEM data confirmed that the isolates obtained could indeed be Rhodococci. All of the isolates could grow in bulk cultures with inorganic medium supplemented with crude oil. Moreover, all of the isolates degraded aliphatic hydrocarbons with lengths between C₁₁ and C₂₉. C₂₃-C₂₉ hydrocarbons were degraded completely. The isolates could grow at 4–37°C. The most unexpected finding was that of the many microorganisms capable of consuming oil, only Rhodococci exhibited this ability in the inactive bitumen mound. The possible mechanisms of how crude oil is transformed into bitumen mounds and mature bitumen are discussed.     

Thermal denaturation of Na- and Li-DNA in salt-free solutions

Thermal denaturation of Na- and Li-DNA from chicken erythrocytes was studied by means of scanning microcalorimetry in salt-free solutions at DNA concentrations (C_p) from 4.5 · 10^?2 to 1 · 10^?3 moles of nucleotides/liter (M). Linear dependencies of DNA melting temperature (T_m) vs lgC_p were obtained: ((1)) ((2)) for Na- and Li-DNA, respectively. Microcalorimetry data were compared with the results of spectrophotometric studies at 260 nm of DNA thermal denaturation in Me-DNA + MeCl solutions at C_p ? (6–8) · 10^?5 M and C_s = 0–40 mM (Me is Na or Li, C_s is salt concentration). It was found that Eqs. (1) and (2) are valid in DNA salt-free solutions over the C_p range 6 · 10^?5?4.5 · 10^?2M. Protonation of DNA bases due to the absorption of CO₂ from air in Na-DNA + NaCl solutions affects DNA melting parameters at C_s < 4 mM. Linear dependence of T_m on lga₊ is found in Na-DNA + NaCl at C_s > 0.4 mMin the absence of contact of solutions with CO₂ from air (a₊ is cation activity). A dependence of [dT_m/dlga₊] on Li⁺ activity was observed in Li-DNA + LiCl solutions at C_s < 10 mM: [dT_m/dlga₊] increases from 17°–18° at C_s > 10 mM to 28°–30° at C_s ? 0.2–0.4 mM. Spectrophotometric measurements at 282 nm show that this effect was caused by protonation of bases in fragments of denatured DNA in neutral solutions. The Poisson–Boltzmann (PB) equation was solved for salt-free DNA at the melting point. The linear dependence of T_m vs lgC_p was interpreted in terms of Manning's condensation theory. PB and Manning's theories fit the experimental data if charge density parameter (ξ) of denatured DNA is in the range 1.8–2.1 (assuming for native DNA ξ = 4.2). Specificity of Li ions in interactions with DNA is discussed. © 1994 John Wiley & Sons, Inc.     

Effect of keratinous waste addition on improvement of crude oil hydrocarbon removal by a hydrocarbon-degrading and keratinolytic mixed culture

The aim of this work was to evaluate the effect of keratinous waste addition on oil-hydrocarbon removal, through a mixed culture of oil-degrading bacteria, with the ability to secrete keratinases. The mixed culture was grown in the media with oil, or oil supplemented with chicken-feathers as the keratinous waste. Residual oil-hydrocarbons were determined as total petroleum hydrocarbons (TPHs) and oil fractions and then quantified by GC–FID and GC–MS.Results showed that in presence of the keratinous waste, the removal of oil-hydrocarbons was 57,400 mg l^?1, meanwhile the treatment without waste presented an oil-hydrocarbons removal of 35,600 mg l^?1. The aliphatic fraction was the most removed in both treatments. In addition, chromatographic profiles indicated that the aliphatic fraction showed different degradation pattern; in the presence of keratinous wastes, the C₁₈ to C₂₈ compounds were preferably removed over the C₁₀ to C₁₇. The addition of keratinous waste not only improved the oil-hydrocarbons removal but, it changed the removal pattern of the target hydrocarbons.     

Sensitive,selective gas chromatographic—mass spectrometric analysis with trifluoroacetyl derivatives and a stable isotope for studying tissue sorbitol-producing activity

One of the major mechanisms involved in diabetic microangiopathy is considered to be an altered polyol pathway. However, clarifying the pathophysiology is difficult due to the lack of a sensitive method for measuring the reduction of glucose to sorbitol in tissue. Here we report a sensitive and selective method for polyol measurement using trifluoroacetyl (TFA) derivatives of polyols and stable isotope-labeled D-sorbitol (U-[¹³C]sorbitol, ¹³C₆H₁₄O₆, 98.7%) as an internal standard. Gas chromatography—mass spectrometry (GC—MS) using an SE-30 capillary column gave elution of TFA derivatives of sugars, polyols and U-[¹³C]sorbitol within 8 min, with clear separation of sorbitol. In the calibration study, the coefficients of correlation between the amount of sorbitol added and that determined in standard solutions containing 0.1–8.0 nmol sorbitol, erythrocyte mixture and liver cytosol mixture were r=0.999, r=0.997 and r=0.997, respectively. The precision of the GC—MS measurement of standard solution was C.V.=4.3%. Because glucose is used as a substrate, the method can clarify the polyol pathway under physiological conditions. With this method, K_m and V_max values of the reductase in erythrocytes were 115±19 mmol/l and 4.42±0.26 nmol/min/g of hemoglobin. In human liver, on the other hand, they were 75±132 mmol/l and 0.77±0.090 nmol/min/mg of protein, respectively. This difference of K_m values suggested that aldehyde reductase rather than aldose reductase is mainly responsible for reducing glucose to sorbitol in the liver. In conclusion, this newly developed method offers a highly sensitive and selective procedure for measuring low concentrations of sorbitol in various tissues and cells and should enable clarification of the kinetics of glucose reduction to sorbitol, which in turn can be used to evaluate the role of an altered polyol pathway in the pathophysiology of diabetic microangiopathy.     

Biodegradation of a dilute waste oil emulsion applied to soil

Summary The use of land treatment for disposal of a dilute waste oil emulsion generated by an aluminum rolling industry was investigated. Major components of the waste, identified by gas chromatography and mass spectrometry, were linear and branched (C₁₂–C₂₅) and fatty acid emulsifiers (primarily, isomers of oleic acid). Hexadecane and pristane were readily biodegraded in vitro when added to soil collected from the waste disposal site. Hydrocarbons and fatty acids extracted from the waste were similarly, biodegraded, however, the rate of decomposition may have depended on the history of waste applications to soil collected from the land treatment site. The apparent half-life of resolvable waste hydrocarbons and fatty acids was 9.5 days in soil which had received waste applications averaging 25.4l m^–2 wk^–1. In contrast, soil receiving either 50.8l m^–2 wk^–1 or no waste application during summer 1987 apparent exhibited half-lives of 28.1 and 60.3 days, respectively. Waste components were restricted to the upper 48 cm of the soil cores collected from the disposal site. Core samples also provided evidence for biodegradation of hydrocarbons and fatty acids as well as an accumulation of other compounds not readily resolvable by gas chromatographyPublished with the approval of the Director of the West Virginia University Agriculture and Forestry Experiment Station as Scientific Article # 2122.     

OCCURRENCE OF ALKANES IN BRAIN MYELIN. COMPARISON BETWEEN NORMAL AND QUAKING MOUSE

Alkanes, a new class of neurolipid, were found in mouse brain, the level being reduced in the Quaking mutant. These hydrocarbons are concentrated in myelin; minor amounts being found in microsomes, mitochondria and synaptosomes. The average recovery is 7.1 μg/mg in normal myelin, 2.2 in the Quaking myelin. The distribution pattern of these alkanes was determined by gas liquid chromatography and was found to differ in normal and Quaking myelin; the hydrocarbons consist mainly of n-alkanes ranging from C₂₁ to C₃₂ with even and odd aliphatic chains.