Uptake Of Naphthalene Research Articles

Adsorption of naphthalene from aqueous solution on activated carbons obtained from bean pods

The preparation of activated carbons from bean pods waste by chemical (K 2CO 3) and physical (water vapor) activation was investigated. The carbon prepared by chemical activation presented a more developed porous structure (surface area 1580 m 2 g −1 and pore volume 0.809 cm 3 g −1) than the one obtained by water vapor activation (258 m 2 g −1 and 0.206 cm 3 g −1). These carbons were explored as adsorbents for the adsorption of naphthalene from water solutions at low concentration and room temperature and their properties are compared with those of commercial activated carbons. Naphthalene adsorption on the carbons obtained from agricultural waste was stronger than that of carbon adsorbents reported in the literature. This seems to be due to the presence of large amounts of basic groups on the bean-pod-based carbons. The adsorption capacity evaluated from Freundlich equation was found to depend on both the textural and chemical properties of the carbons. Naphthalene uptake on biomass-derived carbons was 300 and 85 mg g −1 for the carbon prepared by chemical and physical activation, respectively. Moreover, when the uptake is normalized per unit area of adsorbent, the least porous carbon displays enhanced naphthalene removal. The results suggest an important role of the carbon composition including mineral matter in naphthalene retention. This issue remains under investigation.

Naphthalene metabolism in relation to target tissue anatomy, physiology, cytotoxicity and tumorigenic mechanism of action

This report provides a summary of deliberations conducted under the charge for members of Module C Panel participating in the Naphthalene State-of-the-Science Symposium (NS 3), Monterey, CA, October 9–12, 2006. The panel was charged with reviewing the current state of knowledge and uncertainty about naphthalene metabolism in relation to anatomy, physiology and cytotoxicity in tissues observed to have elevated tumor incidence in these rodent bioassays. Major conclusions reached concerning scientific claims of high confidence were that: (1) rat nasal tumor occurrence was greatly enhanced, if not enabled, by adjacent, histologically related focal cellular proliferation; (2) elevated incidence of mouse lung tumors occurred at a concentration (30 ppm) cytotoxic to the same lung region at which tumors occurred, but not at a lower and less cytotoxic concentration (tumorigenesis NOAEL = 10 ppm); (3) naphthalene cytotoxicity requires metabolic activation (unmetabolized naphthalene is not a proximate cause of observed toxicity or tumors); (4) there are clear regional and species differences in naphthalene bioactivation; and (5) target tissue anatomy and physiology is sufficiently well understood for rodents, non-human primates and humans to parameterize species-specific physiologically based pharmacokinetic (PBPK) models for nasal and lung effects. Critical areas of uncertainty requiring resolution to enable improved human cancer risk assessment were considered to be that: (1) cytotoxic naphthalene metabolites, their modes of cytotoxic action, and detailed low-dose dose–response need to be clarified, including in primate and human tissues, and neonatal tissues; (2) mouse, rat, and monkey inhalation studies are needed to better define in vivo naphthalene uptake and metabolism in the upper respiratory tract; (3) in vivo validation studies are needed for a PBPK model for monkeys exposed to naphthalene by inhalation, coupled to cytotoxicity studies referred to above; and (4) in vivo studies are needed to validate a human PBPK model for naphthalene. To address these uncertainties, the Panel proposed specific research studies that should be feasible to complete relatively promptly. Concerning residual uncertainty far less easy to resolve, the Panel concluded that environmental, non-cytotoxic exposure levels of naphthalene do not induce tumors at rates that can be predicted meaningfully by simple linear extrapolation from those observed in rodents chronically exposed to far greater, cytotoxic naphthalene concentrations.

Adhesion of Pseudomonas putida NCIB 9816-4 to a naphthalene-contaminated soil

The effect of a soil contaminant on the initial adhesion to the soil of a contaminant-degrading soil microorganism in the exponential phase was investigated using naphthalene as the soil contaminant and Pseudomonas putida strain NCIB 9816-4 as the naphthalene-degrading bacteria. P. putida strain DK-1, which is not capable of degrading naphthalene, was used as a control. P. putida NCIB 9816-4 in the exponential phase showed the more adhesion to the soil than that in the stationary phase. In contrast, P. putida DK-1 showed the increased adhesion to the soil when it was in the stationary phase. P. putida NCIB 9816-4 in the exponential phase showed the preferred adhesion to the naphthalene-contaminated soil, whereas the adhesion of P. putida DK-1 was not affected by naphthalene. From the data of surface hydrophobicities of the cells and the soil, the microbial adhesion, especially the initial adhesion to the naphthalene-contaminated soil, takes place through the hydrophobic interaction. We suspect that the surface hydrophobicity of P. putida NCIB 9816-4 in the exponential phase might be increased during the uptake of naphthalene, which caused the preferred adhesion to the naphthalene-contaminated soil.

Uptake and UV-Photooxidation of Gas-Phase Polyaromatic Hydrocarbons on the Surface of Atmospheric Water Films. 2. Effects of Dissolved Surfactants on Naphthalene Photooxidation

The adsorption and photochemical transformations of gas-phase naphthalene were studied in a flow-tube reactor with a view to understanding the photochemical reactions occurring in thin water films such as those of aerosols and fogs. Suwannee River fulvic acid (SRFA) was chosen as a surrogate for the surface active humic-like substances present in atmospheric water films. Experiments were performed on both 450 and 22 mum water films over a wide concentration range of SRFA (0-1000 mg.L-1). The effect of singlet oxygen on the reaction rate in the presence and absence of SRFA was ascertained. Naphthalene molecules can be bound to SRFA through hydrophobic interactions and be distributed in both the water and the SRFA regions. The rate constants for the photochemical reactions of naphthalene were fitted to a model that described the effect of SRFA in these two regions. The kinetic study on the 22 mum film revealed a greater surface reaction enhancement than for the 450 mum film at low SRFA concentrations. However, there was no surface reaction enhancement at high SRFA concentrations. To compare with SRFA, the effect of a conventional surfactant, sodium dodecyl sulfate, on the uptake and photochemical transformations of naphthalene was also studied.

Uptake and Elimination of Naphthalene from Liver, Lung, and Muscle Tissue in the Leopard frog (Rana pipiens)

The effects of a 0–12-hour naphthalene exposure on pulmonary CO2 excretion and bioaccumulation in the leopard frog, Rana pipiens, were investigated. The data showed that naphthalene transport occurred from the aqueous phase into the frog tissue. The first-order rate constant (k in day−1) for the entry of naphthalene from the water into the frog was 0.079 ± 0.007 (k ± 95% C.I.). Bioaccumulation of naphthalene was measured in liver, lung, and thigh muscle tissue. Exposure to naphthalene caused a significant reduction in pulmonary CO2 excretion, particularly following the first 30 minutes of exposure. Pulmonary CO2 excretion returned to baseline levels after 8 hours of exposure, indicating that some degree of acclimation had occurred. Depuration experiments were used to monitor recovery from naphthalene exposure. Recovery of CO2 excretion was evident following 2 hours of depuration and complete elimination of naphthalene from tissues occurred after 3 hours. The data indicate that accumulated polycyclic aromatic hydrocarbons (PAHs) may alter normal physiologic functions such as gas exchange. Since amphibians, such as frogs, are one of the first organisms to come into contact with contaminated water and sediments, the information in this study suggests that this species may be used to assess bioaccumulation and toxicity of PAHs in ecosystems.

Assessment of biochemical components and enzyme activities in the estuarine crab Scylla tranquebarica from naphthalene contaminated habitants

To document the impact of naphthalene, a comparative toxicological research was performed in the estuarine crab Scylla tranquebarica habitant of Ennore creek (polluted site) and Kovalam creek (pristine site) for a period of 6 months. The biochemical constituents, such as protein, carbohydrate, lipid and enzyme activities like acid and alkaline phosphatase, aspartate and alanine transaminase were analysed in hepatopancreas, heamolymph and ovary of the female crabs collected from the two creeks. The results revealed that there was a significant measurable difference in these parameters in the tissues of crabs sampled from the polyaromatic hydrocarbon (PAH) polluted site (Ennore creek) when compared with the reference site (Kovalam creek). In addition naphthalene was detected in gill, hepatopancrease, heamolymph and ovary of the crabs sampled from the polluted creek. The results indicate that the indicators selected for toxic impact in S. tranquebarica may be related to the uptake of naphthalene in the tissues examined and support the feasibility of employing these types of analyses as biochemical biomarkers for PAH contaminant-exposed organisms.

Uptake and Sequestration of Naphthalene and 1,2-Dichlorobenzene by C60

The interactions of common environmental contaminants with C60 have been studied to evaluate the environmental impact of carbon nanomaterials. The adsorption and desorption interaction of the hydrophobic contaminants naphthalene and 1,2-dichlorobenzene with C60 was characterized. Processes that cause the wetting and disaggregating of C60 particles also affect the extent of organic contaminant sorption to C60 aggregates by orders of magnitude. C60 dissolved in organic solvents such as toluene can form stable nanoscale aggregates upon vigorous mixing in water. These nanoscale C60 particles form stable suspensions in water and are referred to as ‘nano-C60’. Desorption of contaminants from stable suspensions of nano-C60 exhibits hysteresis. The experimentally observed adsorption/desorption hysteresis is described by a two-compartment desorption model: first, adsorption to the external surfaces that are in contact with water, and second, adsorption to the internal surfaces within the aggregates.

Heterogeneous Oxidation by Ozone of Naphthalene Adsorbed at the Air-Water Interface of Micron-Size Water Droplets

The mass transfer of naphthalene vapor to water droplets in air was studied in the presence of ozone (O3) in the gas phase. A falling droplet reactor with water droplets of diameters 55, 91, and 182 μm was used for the study. O3 reacted with naphthalene at the air-water interface, thereby decreasing the mass transfer resistance and increasing the rate of uptake of naphthalene into the droplet. A Langmuir-Hinshelwood reaction mechanism at the air-water interface satisfactorily described the surface reaction. The first-order surface reaction rate constant, ks, increased with decreasing droplet size. Three organic intermediates were identified in the aqueous phase as a result of ozonation of naphthalene at the surface of the droplet indicating both peroxidic and nonperoxidic routes for ozonation. The presence of an organic carbon surrogate (fulvic acid) increased both the partition constant of naphthalene and the surface reaction rate of O3. The heterogeneous oxidation of naphthalene by O3 on the droplet was 15 times faster than the homogeneous oxidation by O3 in the bulk air phase, whereas it was only 0.08 times the homogeneous gas-phase oxidation by hydroxyl radicals under atmospheric conditions.

Adsorption of polycyclic aromatic hydrocarbons at the air‐water interface and its role in atmospheric deposition by fog droplets

This review addresses the significance of air-water interfacial adsorption in the fate and transport of polycyclic aromatic hydrocarbons (PAHs) in dispersed systems, such as fog droplets in the atmosphere and air bubbles in wastewater systems. The equilibrium (partition constants) and transport (mass accommodation coefficients) parameters in dispersed systems are discussed. Specific cases where the air-water interfacial adsorption makes a significant impact, such as uptake of naphthalene by fog droplets in a falling droplet reactor and of pyrene removal on air bubbles in a solvent sublation reactor, are discussed as illustrations. The consequence of the air-water interface in atmospheric wet deposition of PAHs by fog droplets is analyzed mathematically.

Lipid‐gel and poly(dimethylsiloxane) film to mimic bioaccumulation in adipocytes

Bioaccumulation is an increasingly important consideration in validation studies of the safety and efficacy of potential drugs. Although an "adipocyte" cell line model has been proven successful to mimic the accumulation of naphthalene in adipocytes, the prolonged incubation time limits its use in high-throughput studies and reduces reproducibility. In this investigation, naphthalene and naphthol accumulation and uptake kinetics of thin poly(dimethylsiloxane) (PDMS) film and lipid nanospheres suspended in a crosslinked gelatin gel (lipid-gel) were compared with those of adipocytes. Unlike the PDMS film, the lipid-gel can mimic the kinetics and extent of naphthalene accumulation in the adipocytes reasonably well. However, the lipid-gel accumulated about twice as much naphthol as the adipocytes, suggesting that hydrophobicity/hydrophilicity of the metabolite may be an important factor in the accuracy of accumulation studies with the lipid-gel. Nonetheless, the lipid-gel system shows promise as an inexpensive, convenient, and reproducible fat mimic for bioaccumulation studies.

Adsorption and transport of gas-phase naphthalene on micron-size fog droplets in air.

Aromatic hydrocarbon vapors adsorb to the air/water interface and are transported by wet deposition processes via fog, mist, and rain. A falling droplet apparatus was used to study the adsorption and uptake of naphthalene vapor on water droplets with diameters ranging from 14 to 200 microm. Uptake of naphthalene vapor greater than that predicted by bulk (air-water) phase equilibrium was noted for diameters less than 50 microm and was attributed to surface adsorption. The experimental values of the droplet-vapor partition constants were used to obtain the mass accommodation coefficient for naphthalene at the interface. The effect of temperature on the mass accommodation coefficientwas measured. The effects of a synthetic surfactant and a natural organic carbon surrogate (Suwanee Fulvic acid) on the uptake of naphthalene vapors on water droplets were also examined. Small droplet diameter, decreased temperature, and the presence of dissolved surface-active material in water enhanced the uptake of naphthalene into fog droplets.

Removal of aqueous-phase polynuclear aromatic hydrocarbons using aspen wood fibers

Roadway runoff derived polynuclear aromatic hydrocarbons (PAHs) impact the quality of surface and ground water. Inexpensive aspen wood fibers have been investigated as a means to remove dissolved PAH under laboratory conditions. Our isotherm experiments demonstrated that the uptake of naphthalene, fluorene, anthracene, and pyrene required up to 12.5 days to reach equilibrium. Aspen wood–water sorption coefficients, K ww, were linearly correlated to octanol–water partition coefficients and the molecular weight of the studied PAH compounds. The correlation between K ww and molecular weight was the most significant. Column experiments were carried out to study the sorption and desorption of fluorene, anthracene, and pyrene under dynamic conditions. The results indicate linear sorption, but non-linear desorption behavior. The degree of desorption was inversely correlated to a compound’s hydrophobicity. Flow interruption experiments showed that sorption and desorption was rate limited. A mass balance of the sorption and desorption tests indicated that sorptive uptake exceeded desorptive release over a given number of pore volumes. Further, absolute mass-removal efficiency increased with the molecular weight and hydrophobicity of the PAH compound. Batch and column studies demonstrated that aspen wood has the potential to become an effective remedial agent for PAH in stormwater runoff or other PAH contaminated waters.

NAPHTHALENE REMOVAL FROM AQUEOUS SYSTEMS BY SAGITTARIUS SP

ABSTRACT Naphthalene is a polyaromatic hydrocarbon (PAH) present in many sediment-water systems. The uptake of naphthalene by an aquatic plant, arrowhead (Sagittaria sp.), was studied in a series of batch systems and continuous flow systems. Batch experiments were conducted in a fed-batch mode, and naphthalene was administered in consecutive spike doses. Results from batch experiments indicated that the rate of naphthalene removal by arrowhead in the presence of light was 0.114 ± 0.061 h−1, at a 90% confidence interval. Naphthalene removal by arrowhead occurred even in the absence of light, although this rate was about 25% of that in the presence of light. Results indicated that repeated exposures to naphthalene for a single arrowhead plant may decrease its capacity for naphthalene uptake, particularly after the first exposure. Naphthalene tended to deposit out in CSTRs where no arrowhead was present, indicating that while the naphthalene may not have been present in the water column, it was not removed from the system. Results from CSTR experiments indicated that under well-mixed quasi-steady state conditions, naphthalene removal by arrowhead in the presence of light was about 40%. Photolytic degradation of naphthalene in the absence of arrowhead was about 15%, when additional mixing was provided to simulate scouring.

Mass transfer effects on microbial uptake of naphthalene from complex NAPLs

The above article printed in Biotechnology and Bioengineering without Figures 1–4. We offer on the following pages the article printed in its entirety with Figures 1–4. We apologize for any inconvenience this error may have caused.

Uptake of polycyclic aromatic hydrocarbon compounds by the gills of the bivalve mollusk Elliptio complanata

Polycyclic aromatic hydrocarbons (PAHs) and herbicides are important contaminants of world water systems with effects on aquatic organisms. The uptake of naphthalene, anthracene, and chrysene by gills of the bivalve mollusk Elliptio complanata was determined. Additionally, the effects of paraquat, atrazine, alachlor, 2,4-dichlorophenoxyacetic acid (2,4-D), and 2,4-dinitrophenol on the uptake of these compounds were also determined. The results indicate (1) the uptake of anthracene is approximately equivalent to that of chrysene and the uptake of either of these compounds is higher than that of naphthalene; (2) comparisons of uptakes with that of inulin, which occupies only extracellular space, show that all compounds studied are taken up; (3) the uptakes of naphthalene, anthracene, and chrysene are initially altered by the presence of herbicides such as paraquat, alachlor, 2,4-D, atrazine, and 2,4-dinitrophenol.

Influence of dispersants on the bioavailability and trophic transfer of petroleum hydrocarbons to larval topsmelt ( Atherinops affinis)

Use of chemical dispersants as oil spill clean-up agents may alter the normal behavior of petroleum hydrocarbons (PH) by increasing their functional water solubility, resulting in increased bioavailability and altered interactions between dispersant, oil, and biological membranes. The objective of this research was to determine the impact of dispersing agents on PH bioavailability and trophic transfer to larval fish from primary levels of a marine food chain. Uptake, bioaccumulation, depuration, and metabolic transformation of a model PH, [ 14C]naphthalene, were measured and compared for Prudhoe Bay crude oil (PBCO) dispersed with Corexit 9527® (DO) and undispersed preparations of the water-accommodated fraction (WAF) of PBCO. The model food chain consisted of a primary producer, Isochrysis galbana; and a primary consumer, the rotifer, Brachionus plicatilis; and larval topsmelt, Atherinops affinis. Direct aqueous (AQ) exposure was compared with combined aqueous and dietary (AQ&D) exposure. Dispersants altered the uptake and depuration processes of naphthalene, independent of aqueous concentrations, in primary trophic species of a marine food chain. The amount of naphthalene taken up by topsmelt was initially significantly ( P≤0.05) enhanced in the presence of dispersant, reaching a maximum more quickly than undispersed samples. Dispersion treatment significantly increased naphthalene dispension in topsmelt ( P≤0.05) from both AQ and AQ&D exposures. No significant change in naphthalene uptake by fish was observed with the addition of contaminated food for either WAF or DO medium; however, both uptake and depuration rate constants varied significantly with route of exposure consistent with greater naphthalene turnover. The majority (≥72%) of naphthalene-derived radioactivity from fish tissue following all exposures was in the parent form, with smaller quantities of α- and β-naphthols, α- and β-naphthyl sulfates, and an unidentified derivative.

SHORT COMMUNICATION: HYDROCARBON ACCUMULATION AND DISCHARGE BY THE CRAYFISH IN SOME RIVERS OF LAGOS, NIGERIA

Crayfishes exposed to 14C-naphthalene-5% of an aqueous fraction of crude oil in open non-aerated glass jars for 4 h at 25 0C showed no significant differences (P > 0.25) in the amount of naphthalene uptake. Different parts of the crayfishes were quantified for naphthalene uptake and cephalothorax containing hepatopancreas (a food absorption organ) was found to have greater uptake than the tail flesh or tail skeleton. Release of the oil from the crayfishes that were exposed for 1, 2, 3 or 4 h and later placed in open non-aerated jars containing oil-free water showed greater loss of most of the 14C activity during the first 24 h, there was little losses at 48, 72 and 96 h. There was significant volatilization (P (Received May 2, 2001; revised October 19, 2001) Bull.Chem.Soc.Ethiop. 2001, 15(2), 167-172

Mass transfer effects on microbial uptake of naphthalene from complex NAPLs

The bioavailability of naphthalene present as a component of a complex nonaqueous phase liquid(NAPL) comprised by nine aromatic compounds was investigated. Specifically, the effects of naphthalene mass transfer from the NAPL to the aqueous phase on rates of its microbial degradation were examined. The investigations were conducted using a pure culture, ATCC 17484, and a mixed culture of naphthalene-degrading bacteria, the former having been implicated previously in the direct uptake of sorbed naphthalene. The studies were conducted in mass-transfer-limited, segregated-phase reactors(SPRs) in which both the NAPL and aqueous phases were internally well-mixed. A 30-day active biodegradation period was preceded and followed by a 5-7-day period devoid of bioactivity, during which time the rates and extents of mass transfer of components from the NAPL to the aqueous phase were quantified. The NAPL-phase naphthalene mass depletion profiles during biodegradation were compared to those predicted by assuming maximum mass depletion under mass-transfer-limited conditions using both pre- and post-biodegradation dissolution rate and equilibrium parameters. The observed mass depletion rates were high during the initial stages of biodegradation but decreased significantly in later stages. Throughout biodegradation, even in the initial rapid stage, mass depletion rates never exceeded maximum predicted rates based on pre-biodegradation mass transfer parameters. Reduced depletion rates in the later stages appear to relate to mass transfer hindrance caused by formation of biofilms at the NAPL-water interface.

Mass transfer effects on microbial uptake of naphthalene from complex NAPLs

The bioavailability of naphthalene present as a component of a complex nonaqueous phase liquid (NAPL) comprised by nine aromatic compounds was investigated. Specifically, the effects of naphthalene mass transfer from the NAPL to the aqueous phase on rates of its microbial degradation were examined. The investigations were conducted using a pure culture, ATCC 17484, and a mixed culture of naphthalene-degrading bacteria, the former having been implicated previously in the direct uptake of sorbed naphthalene. The studies were conducted in mass-transfer-limited, segregated-phase reactors (SPRs) in which both the NAPL and aqueous phases were internally well-mixed. A 30-day active biodegradation period was preceded and followed by a 5-7-day period devoid of bioactivity, during which time the rates and extents of mass transfer of components from the NAPL to the aqueous phase were quantified. The NAPL-phase naphthalene mass depletion profiles during biodegradation were compared to those predicted by assuming maximum mass depletion under mass-transfer-limited conditions using both pre- and post-biodegradation dissolution rate and equilibrium parameters. The observed mass depletion rates were high during the initial stages of biodegradation but decreased significantly in later stages. Throughout biodegradation, even in the initial rapid stage, mass depletion rates never exceeded maximum predicted rates based on pre-biodegradation mass transfer parameters. Reduced depletion rates in the later stages appear to relate to mass transfer hindrance caused by formation of biofilms at the NAPL-water interface.

Naphthalene uptake by a Pseudomonas fluorescens isolate

TThe uptake of naphthalene has been investigated in the metabolizing cells of Pseudomonas fluorescens utilizing [1-14C]naphthalene. The uptake displayed an affinity constant (Kt) of 11 μM and a maximal velocity (Vmax) of 17 nmol·h-1·mg-1 cellular dry weight. Naphthalene uptake was not observed in a mutant strain, TG-5, which was unable to utilize naphthalene as a sole source of carbon for growth. Uptake was significantly inhibited (~90%) by the presence of growth-inhibiting levels of either azide or 2,4-dinitrophenol and was sensitive to the presence of structural analogues of naphthalene. The intracellular levels of ATP were not significantly reduced by the presence of either azide or 2,4-dinitrophenol. The presence of alpha-naphthol was found to noncompetitively inhibit naphthalene uptake, displaying a Ki of 0.041 μM. It is concluded that the first step in the utilization of naphthalene by Pseudomonas fluorescens is its transport into the cell by a specific energy-linked transport system.Key words: naphthalene, PAH, biodegradation, transport.