Uptake Of Naphthalene Research Articles

Exploring the phytoremediation capacity of Portulaca oleracea naphthalene aromatic hydrocarbon contaminants: a physiological and biochemical study.

This study is aimed to explore the potential of purslane (Portulaca oleracea L.) as a phytoremediation candidate for the removal of naphthalene in a hydroponic system; moreover, the impacts of naphthalene on the physiological and biochemical characteristics of the plant were investigated. Four different naphthalene concentrations (0, 15, 30, and 60ppm) were selected for the experiments, with an additional control treatment without plants containing 60ppm naphthalene. Each treatment, utilizing a total of 20 hydroponic containers, consisted of 4 replicates. The results indicated that naphthalene led to a reduction in root and shoot growth. The root weight decreased from 17mg in the control group to 6mg in the 60ppm naphthalene treatment, while the shoot weight decreased from 107.5mg in the control group to 65.7mg in the 60ppm naphthalene treatment. Besides, the different naphthalene concentrations had an impact on the photosynthetic pigments. Compared to the control treatment, under severe stress conditions, chlorophyll a decreased by 51.85%, chlorophyll b decreased by 48.14%, and carotenoids decreased by 54.59%; however, anthocyanin, compared to the control treatment, increased by 30.1% under severe stress conditions. The presence of naphthalene also resulted in increased levels of malondialdehyde, hydrogen peroxide, and proline in both roots and shoots at various naphthalene concentrations. In roots, malondialdehyde increased by 40.74%, H2O2 increased by 3%, and proline increased by 75.6%, while malondialdehyde increased by 43.16%, H2O2 increased by 5.34%, and proline increased by 59.48% in shoots under severe stress conditions and compared to the control treatment. Root and shoot protein levels decreased by 64.49% and 32.26%, respectively. Furthermore, the antioxidant enzymes of glutathione S-transferase, superoxide dismutase, catalase, and ascorbate peroxidase showed increased activities in both roots and shoots under severe naphthalene stress conditions. Purslane demonstrated the ability to remove approximately 80% of naphthalene from the medium. In conclusion, this plant has an effective participation in naphthalene uptake and mitigates the adverse effects of naphthalene by enhancing antioxidant enzyme and proline activities.

Renal excretion of 1,2-dihydroxynaphthalene (DHN) in firefighting instructors after exposure to polycyclic aromatic hydrocarbons (PAHs) during live fire training

Exposure of firefighting instructors to polycyclic aromatic hydrocarbons (PAHs) such as naphthalene is unavoidable during live fire training. The study aimed to investigate naphthalene uptake by measuring the urinary excretion of the naphthalene metabolite 1,2-dihydroxynaphthalene (DHN), to describe the DHN elimination kinetics and to evaluate the results by comparison to further biomarkers of PAH exposure. N = 6 male non-smoking firefighting instructors completed five training sessions each in a residential fire simulation unit under respiratory protection. All participants provided two urine samples before and another seven samples within an 18-h-interval after each session. DHN was detected by gas chromatography/tandem mass spectrometry (GC–MS/MS) in all samples (n = 237) with median concentrations ranging from 3.3 µg/g crea. (range 0.9–10.2) before exposure to 134.2 µg/g crea. (43.4–380.4) post exposure. Maximum elimination found 3.3 h (median) after onset of exposure decreased with a mean half-life of 6.6 h to 27.1 µg/g crea. (15.7–139.5) 18 h after training. DHN sensitively indicated a presumed dermal naphthalene intake during training, showing similar elimination kinetics like other naphthalene metabolites. Internal exposure of the participants transiently exceeded exposures determined for non-smokers in the general population, but was lower than at other workplaces with PAH exposure. Despite limited uptake, accumulation is possible with daily exposure.

Sorption of three PAHs profile groups using eco-friendly and inexpensive hydroxyapatite extracted from camel bone

Hydroxyapatite (HAp) was used in the sorption study for three different polycyclic aromatic hydrocarbons (PAHs) ring structures (Naphthalene (NAP), Anthracene (ANT), and Chrysene). HAp powders were produced from Camelus bone as an eco-friendly and inexpensive source. Three distinct surface areas (66.56, 94.88, and 94.35 m2/g) at three different temperatures (500, 650, and 900 °C), were applied to prepare the HAp500, HAp650, and HAp900 samples after passing CO2 at 700 °C. It was obvious that the surface area of HAp was greatest at 650 °C as compared to 500 °C with a very small variation in uptake between HAP650 and HAP900. Furthermore, for ANT, HAp900 provides the best uptake. In addition, HAp650 is the best since calcining at 650 °C is less expensive than calcining at 900 °C. The effect of shaking time on the sorption of NAP, ANT, and CHR dissolved in n-hexane was carried out using HAp650. The impacts of sorbent amount, concentration, and temperature were studied. The study indicated that the uptake was 66.89, 69.49, and 19.67 mg/g after 120 min of equilibration. It was observed that the uptake of NAP, ANT, and CHR increased as the temperature increased up to 35 °C. A slight increase was obtained from 35–55 °C, indicating that the adsorption occurring on the HAp650 surface is endothermic. The positive values of Δ H demonstrated the endothermic nature of the adsorption process. Furthermore, the positive entropy of adsorption represents the adsorbent material’s affinity for NAP, ANT, and CHR. In addition, several isotherm models were used to deduce an adsorption mechanism. The adsorption system’s R2 values were 0.9615 for NAP, 0.8666 for ANT, and 1.00 for CHR. These values agree well with the Langmuir isotherm.

Tailoring microstructure and microenvironment in carbonaceous sorbent for all-round superior naphthalene capture

Sorptive capture and recycling of gaseous naphthalene from industrial emissions are of both environmental significance and economic benefit. Constructing carbonaceous sorbents with matchable pore size and adequate active sites is significant towards the trade-off between adsorption and desorption for naphthalene. In this study, we developed a series of porous carbonaceous sorbents (ECSCs) using facile, inexpensive, and effective solution combustion synthesis (SCS) with subsequent calcination and pickling. The MgO@C precursors were fabricated via a fast and self-exothermic combustion reaction, and after calcination and MgO removal by pickling, the tailored pore structure was created. The morphology, porous structure, and surface chemical properties of ECSCs are precisely controlled by adjusting the type and content of fuel in combustion. For the optimized ECSC-G14 prepared on fuel-balanced condition, its layer-by-layer network facilitates adsorption mass transfer, and its high specific surface area (1987 m2·g−1) and abundant 3–6 nm mesoporosity promotes the accessibility of active sites. Consequently, an unprecedented high naphthalene uptake (3.075 mmol·g−1 at 398 K) and fast kinetics (∼1.43 × 10−2 s−1 at 2.82 × 10−3 mol·m−3 feed concentration) were achieved. Combined characterization and molecular calculation revealed the synergistic contribution of O and N to reversible adsorption with superb regenerability (Ea of 42.71 kJ·mol−1) and cyclic properties. This study provides an effective strategy and theoretical support to customize the properties of porous carbons, overcoming the adsorption–desorption dilemma for gas purification.

Migration and adsorption of naphthalene in road-deposited sediments from stormwater runoff: Impact of the particle size

In this study, we explored the impact of RDS particle size on the migration dynamics of RDS and naphthalene through rigorous wash-off experiments. The results illuminated that smaller RDS particles showed higher mobility in stormwater runoff. On the other hand, RDS particles larger than 150 μm showed migration ratios below 2 %, suggesting that naphthalene adsorbed on larger RDS primarily migrated in dissolved form. Furthermore, we investigated the migration behaviors of RDS and naphthalene under varied conditions, including rainfall intensity, duration, and naphthalene concentrations. Larger rainfall intensity promoted the naphthalene release from RDS, while long rainfall duration (≥10 min) impeded the migration velocities (≤2.91 %/5 min for RDS, and ≤3.32 %/5 min for corresponding naphthalene) of RDS and naphthalene. Additionally, higher naphthalene concentrations in RDS diminished migration ratios of dissolved naphthalene. Significantly, the maximum uptake of naphthalene on RDS was 6.02 mg/g by the adsorption Langmuir isotherm. Importantly, the adsorption process of naphthalene in RDS is primarily governed by the physical adsorption, as demonstrated by the successive desorption experiments, which showed the desorption rate of up to 87.32 %. Moreover, advanced characterizations such as XPS, FTIR and Raman spectra further confirmed the physical nature of the adsorption process. These findings may help the understanding of the migration behavior of other pollutants in urban surface particulates.

Salinity-dependent mitigation of naphthalene toxicity in migratory Takifugu obscurus juveniles: Implications for survival, oxidative stress, and osmoregulation

Naphthalene, an environmental pollutant classified as a polycyclic aromatic hydrocarbon (PAH), can induce toxicity in fish and other aquatic organisms. Through our investigation, we determined how Takifugu obscurus juveniles were affected by naphthalene (0, 2 mg L−1) exposure in terms of oxidative stress biomarkers and Na+/K+-ATPase activity in various tissues (gill, liver, kidney and muscle) under dissimilar salinities (0, 10 psu). Results suggest that naphthalene exposure significantly affects the survival of T. obscurus juveniles and leads to significant changes in the levels of malondialdehyde, superoxide dismutase, catalase, glutathione, and Na+/K+-ATPase activity, which are indicative of oxidative stress and emphasized the risks associated with osmoregulatory function. The higher salinity affected on the noxious effects of naphthalene can be observed, resulting in decreased biomarker levels and increased Na+/K+-ATPase activity. Salinity levels affected the uptake of naphthalene and its impact on different tissues, with high salinity conditions having mitigating effects on oxidative stress and naphthalene uptake in the liver and kidney tissues. Increased Na+/K+-ATPase activity was observed in all tissues treated with 10 psu and 2 mg L−1 naphthalene. Our findings deepen the understanding of T. obscurus juveniles' physiological responses to naphthalene exposure, and highlight the potential mitigating effects of salinity. These insights can inform the development of appropriate conservation and management practices to protect aquatic organisms from susceptibility.

Uptake and accumulation of naphthalene, phenanthrene, and benzo(b)fluoranthene in winter wheat affected by foliar exposure at different growth stages.

Foliar uptake, as an important pathway of polycyclic aromatic hydrocarbons (PAHs) accumulation in winter wheat, has a great contribution to wheat PAHs, which mainly depends on atmospheric PAHs level. An indoor simulation experiment was conducted to explore the effects of foliar exposure to PAHs at different growth stages on PAHs uptake in wheat. Three levels (0, 0.75, 4.5mg L-1) of mixed solution of three PAHs (Σ3PAHs) including naphthalene (NAP), phenanthrene (PHE), and benzo(b)fluoranthene (BbF) were sprayed on leaves of two varieties (Yunong, YN; Xiaoyan, XY) of winter wheat (Triticum aestivum L.) during the booting, heading, pre-filling, and post-filling stage. The results showed that the sprayed PAHs exhibited little effects on the growth of the two varieties except the stem biomass of YN was significantly (p < 0.05) reduced when high concentration of PAHs was applied at the post-filling stage. PAHs concentration in winter wheat grain was highest under foliar exposure at the pre-filling stage, while the lowest was found under foliar exposure at the post-filling stage. Transfer factor of PAHs from stem to root (TFroot/stem) of three PAHs when foliar exposure to PAHs at the booting and heading stage was significantly (p < 0.001) higher than that at the pre-filling and post-filling stage, while TFgrain/glume of three PAHs when foliar exposure to PAHs at pre-filling stage was significantly (p < 0.01) higher than that at the other three stages. These results indicated that foliar exposure to PAHs during the vegetative growth stage was transferred and distributed to the root, while PAHs are mainly transferred and accumulated to the grain during the grain filling stage. Additionally, the higher lipophilic PAHs showed a lower ability to transfer from the glume to grain, and larger flag leaf area had the potential to promote the enrichment of PAHs in grain. This study indicated that the health risk of PAHs in winter wheat could be effectively reduced by controlling atmospheric PAHs level during pre-filling stage.

Efficient removal of naphthalene from aqueous solutions using a nanoporous kaolin/Fe3O4 composite

The presence of naphthalene in environment has carcinogenic properties and threatens human health. Therefore, the removal of naphthalene from wastewater using eco-friendly materials and novel technologies has received tremendous attention. In this study, the performance of a kaolin/Fe3O4 composite toward the uptake of naphthalene from aqueous media was assessed for the first time. The systematic study of the naphthalene adsorption by the kaolin/Fe3O4 composite, using the central composite design, revealed that an increase in solution pH, contact time, or composite dose improves the removal efficiency of naphthalene. Considering the desirability index of 1.00, the optimum conditions for the removal of naphthalene were found at a composite dose of 4.8 g L−1, contact time of 66 min, and solution pH 6.5 to achieve 97% removal efficiency from a solution containing 10 mg L−1 naphthalene. In comparison with the other clay-based composites, the equilibrium removal efficiency of naphthalene by the kaolin/Fe3O4 composite was significantly high. These results indicated that the kaolin/Fe3O4 composite is one of the most efficient adsorbents for the treatment of naphthalene-contaminated water using the adsorption process.

Optimization of process parameters for naphthalene removal onto nano-iron oxide/carbon composite by response surface methodology, isotherm and kinetic studies

The influence of design parameters such as dosage, experimental time and process temperature on the adsorptive removal of naphthalene and yield of the nano-Fe3O4/carbon composite synthesized from palm shell activated carbon was determined. The involved synthesis mechanism for composite was also found to be cost-effective. Based on the composite design mechanism, various quadratic models were found out to correlate the dynamic parameters with the symmetric responses. The nano-Fe3O4/carbon composite conditions were centrally optimized using response surface mechanism by maximizing both the yield of nano-Fe3O4/carbon composite and uptake of naphthalene within the predetermined ranges involved in this study. The optimum parameters for synthesizing nano-Fe3O4/carbon composite from palm shell for adsorption of naphthalene were as follows: dosage of 6 g/l, reaction time of 150 min and process temperature of 40 °C which obtained 120.87 mg/g of naphthalene uptake and 21.46% composite yield. The Langmuir model well agreed for experimental fitting of the observed data. The reaction kinetics followed the best utilization of pseudo-second-order mechanism. The experimental conditions quite agreed with the predicted results of the model. BET analysis confirmed the surface distribution to be 695 m2/g and SEM analysis resulted in maximum pore development onto nano-iron oxide/carbon composite.

Measurement of Naphthalene Uptake by Combustion Soot Particles

In this study, we designed and constructed an experimental laboratory apparatus to measure the uptake of volatile organic compounds (VOCs) by soot particles. Results for the uptake of naphthalene (C10H8) by soot particles typical of those found in the exhaust of an aircraft engine are reported in this paper. The naphthalene concentration in the gas phase and naphthalene attached to the particles were measured simultaneously by a heated flame ionization detector (HFID) and a time-of-flight aerosol mass spectrometer (ToF AMS), respectively. The uptake coefficient for naphthalene on soot of (1.11 ± 0.06) × 10(-5) at 293 K was determined by fitting the HFID and AMS measurements of gaseous and particulate naphthalene to a kinetic model of uptake. When the gaseous concentration of naphthalene is kept below the saturation limit during these experiments, the uptake of naphthalene can be considered the dry mass accommodation coefficient.

Uptake and toxicity of polycyclic aromatic hydrocarbons in terrestrial springtails—studying bioconcentration kinetics and linking toxicity to chemical activity

Passive dosing applies a polymer loaded with test compound(s) to establish and maintain constant exposure in laboratory experiments. Passive dosing with the silicone poly(dimethylsiloxane) was used to control exposure of the terrestrial springtail Folsomia candida to six polycyclic aromatic hydrocarbons (PAHs) in bioconcentration and toxicity experiments. Folsomia candida could move freely on the PAH-loaded silicone, resulting in exposure via air and direct contact. The bioconcentration kinetics indicated efficient uptake of naphthalene, anthracene, and pyrene through air and (near) equilibrium partitioning of these PAHs to lipids and possibly the waxy layer of the springtail cuticle. Toxicities of naphthalene, phenanthrene, and pyrene were related to chemical activity, which quantifies the energetic level and drives spontaneous processes including diffusive biouptake. Chemical activity-response relationships yielded effective lethal chemical activities (La50s) well within the expected range for baseline toxicity (0.01-0.1). Effective lethal body burdens for naphthalene and pyrene exceeded the expected range of 2 to 8 mmol kg(-1) fresh weight, which again indicated the waxy layer to be a sorbing phase. Finally, chemical activities were converted into equilibrium partitioning concentrations in lipids yielding effective lethal concentrations for naphthalene and phenanthrene in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Passive dosing was a practical approach for tightly controlling PAH exposure, which in turn provided new experimental possibilities and findings.

Adsorption uptake of synthetic organic chemicals by carbon nanotubes and activated carbons

Carbon nanotubes (CNTs) have shown great promise as high performance materials for adsorbing priority pollutants from water and wastewater. This study compared uptake of two contaminants of interest in drinking water treatment (atrazine and trichloroethylene) by nine different types of carbonaceous adsorbents: three different types of single walled carbon nanotubes (SWNTs), three different sized multi-walled nanotubes (MWNTs), two granular activated carbons (GACs) and a powdered activated carbon (PAC). On a mass basis, the activated carbons exhibited the highest uptake, followed by SWNTs and MWNTs. However, metallic impurities in SWNTs and multiple walls in MWNTs contribute to adsorbent mass but do not contribute commensurate adsorption sites. Therefore, when uptake was normalized by purity (carbon content) and surface area (instead of mass), the isotherms collapsed and much of the CNT data was comparable to the activated carbons, indicating that these two characteristics drive much of the observed differences between activated carbons and CNT materials. For the limited data set here, the Raman D:G ratio as a measure of disordered non-nanotube graphitic components was not a good predictor of adsorption from solution. Uptake of atrazine by MWNTs having a range of lengths and diameters was comparable and their Freundlich isotherms were statistically similar, and we found no impact of solution pH on the adsorption of either atrazine or trichloroethylene in the range of naturally occurring surface water (pH = 5.7–8.3). Experiments were performed using a suite of model aromatic compounds having a range of π-electron energy to investigate the role of π–π electron donor–acceptor interactions on organic compound uptake by SWNTs. For the compounds studied, hydrophobic interactions were the dominant mechanism in the uptake by both SWNTs and activated carbon. However, comparing the uptake of naphthalene and phenanthrene by activated carbon and SWNTs, size exclusion effects appear to be more pronounced with activated carbon materials, perhaps due to smaller pore sizes or larger adsorption surface areas in small pores.

Eichhornia crassipes capability to remove naphthalene from wastewater in the absence of bacteria

The aim of the current study was to investigate the potential of an aquatic plant, the water hyacinth (Eichhornia crassipes) devoid rhizospheric bacteria, to reduce naphthalene (a polyaromatic hydrocarbon) present in wastewater and wetlands.The capability of sterile water hyacinth plants to remove naphthalene from water and wastewater was studied in batch systems. Water hyacinths enhance the removal of pollutants through their consumption as nutrients and also through microbial activity of their rhizospheric bacteria.Experimental kinetics of naphthalene removal by water hyacinth coupled with natural rhizospheric bacteria was 100% after 9d. Plants, decoupled of rhizospheric bacteria, reduced naphthalene concentration up to 45% during 7d. Additionally, naphthalene uptake by water hyacinth revealed a biphasic behavior: a rapid first phase completed after 2.5h, and a second, considerably slower rate, phase (2.5–225h). In conclusion, water hyacinth devoid rhizospheric bacteria reduced significantly naphthalene concentration in water, revealing a considerable plant contribution in the biodegradation process of this pollutant.

Microarray analysis of the phytoremediation and phytosensing of occupational toxicant naphthalene

Naphthalene is of global environmental concern because it is assumed to contribute considerably to human cancer risk. Plants are important in removing naphthalene from the atmosphere and soil. However, there remains insufficient knowledge on plant response to this compound. To determine the mechanism of naphthalene uptake and transduction in plants, as well as plant response to this compound, a microarray system was used to analyze gene expression patterns in Arabidopsis thaliana after irrigation with 2.0 mM naphthalene. A total of 247 differentially expressed genes were identified as upregulated by naphthalene. These genes might specifically contribute to naphthalene uptake, transformation, conjugation, and compartmentalization in the plant. The potential role of upregulated genes in plant defense to naphthalene and the use of phytosensing for naphthalene detection were also discussed.

Novel method for in situ visualization of polycyclic aromatic hydrocarbons in mangrove plants

Two-photon laser confocal scanning microscopy (TPLCSM) was first used to visualize the uptake and movement of naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR), from separately contaminated hydroponics solutions into living Kandelia candel (L.) Druce seedlings. With this non-destructive and non-chemical extraction technique, the experimental results revealed that three types of polycyclic aromatic hydrocarbons (PAH) were observed moving into the K. candel and its translocation to radicle, hypocotyl and leaf, and the transmission rates of these PAH in the K. candel were in the order of NAP > PHE > PYR. Data demonstrate the manner in which PAH enter, transport, and distribute within the K. candel, and provided us some valuable information on uptake and translocation mechanism of PAH. These findings may help to optimize the phytoremediation strategies of PAH in mangrove wetlands.

Adsorption of naphthalene onto sonicated talc from aqueous solutions

The adsorption behavior of naphthalene onto naturally hydrophobic talc from aqueous solution was investigated in this study. The natural talc was first pretreated by sonication to improve the surface characteristics and enhance the uptake capacity by increasing the specific surface area (SSA) of talc. The naphthalene uptake of talc was found as 276 mg g −1 and increased to 359 mg g −1 after the sonication. Adsorption studies also showed that the adsorption of naphthalene onto the sonicated talc was not affected by changes in pH suggesting that the main driving forces for naphthalene adsorption onto talc was hydrophobic bonding rather than electrostatic force. The pseudo-first and pseudo-second orders and intraparticle diffusion equation were used to evaluate the kinetic data and the constants were determined. Adsorption process of naphthalene onto talc followed the pseudo-second-order rate expression for different initial naphthalene concentrations. The Langmuir and Freundlich isotherm models were used to model the isotherm data for their applicability. The Freundlich isotherm best fitted for the adsorption of naphthalene onto talc.

Upper Respiratory Tract Uptake of Naphthalene

Naphthalene is a nasal toxicant and carcinogen in the rat. Upper respiratory tract (URT) uptake of naphthalene was measured in the male and female F344 rat at exposure concentrations of 1, 4, 10, or 30 ppm at inspiratory flow rates of 150 or 300 ml/min. To assess the potential importance of nasal cytochrome P450 (CYP) metabolism, groups of rats were pretreated with the CYP inhibitor 5-phenyl-1-pentyne (PP) (100 mg/kg, ip). In vitro metabolism of naphthalene was similar in nasal tissues from both genders and was reduced by 80% by the inhibitor. URT uptake in female rats was concentration dependent with uptake efficiencies (flow 150 ml/min) of 56, 40, 34, and 28% being observed at inspired concentrations of 1, 4, 10, and 30 ppm, respectively. A similar effect was observed in male rats (flow 150 ml/min) with uptake efficiencies of 57, 49, 37, and 36% being observed. Uptake was more efficient in the male than female rat, likely due to their larger size (226 vs. 144 g). Uptake of naphthalene was significantly reduced by inhibitor pretreatment with the effect being greater at the lower inspired concentrations. Specifically, in pretreated female rats (150 ml/min), URT uptake averaged 25, 29, and 26% at inspired concentrations of 4, 10, and 30 ppm, respectively. Thus, the concentration dependence of uptake was virtually abolished by PP pretreatment. These results provide evidence that nasal CYP metabolism of naphthalene contributes to URT scrubbing of this vapor and is also involved in the concentration dependence of uptake that is observed.

Influence of naphthalene biodegradation on the adhesion of Pseudomonas putida NCIB 9816-4 to a naphthalene-contaminated soil

In an earlier study, Pseudomonas putida NCIB 9816-4, which was one of the most studied naphthalene-degrading bacteria, showed the preferred adhesion to the naphthalene-contaminated soil when it was in the exponential growth phase. The adhesion was found to take place through a hydrophobic interaction. We postulated that the surface hydrophobicity of P. putida NCIB 9816-4 in the exponential growth phase might be increased during the uptake of naphthalene, which caused the preferred adhesion to the naphthalene-contaminated soil. To verify this postulate, a plasmid-cured strain of P. putida NCIB 9816-4 was obtained in this study and compared with the wild-type for adhesion to the naphthalene-contaminated soil. Only the wild-type in the exponential growth phase showed increased adhesion to naphthalene-contaminated soil. The water contact angles of the two strains were measured in the presence and in the absence of naphthalene as indices of surface hydrophobicity. The water contact angle of the wild-type increased in the presence of naphthalene, whereas that of the cured strain did not change. We conclude that the uptake of naphthalene during naphthalene biodegradation in the exponential growth phase of P. putida NCIB 9816-4 made the cell surface more hydrophobic, resulting in increased adhesion to naphthalene-contaminated soil.

A comparative study on the uptake of polycyclic aromatic hydrocarbons by Anodonta californiensis

Uptake of polycyclic aromatic hydrocarbons (PAHs) by the freshwater bivalve mollusc Anodonta californiensis was examined in the presence and absence of surfactant in order to gain further insight into mixture toxicity and to predict whether certain mixtures have negative and/or positive effects on aquatic organisms. In the presence of surfactant, the uptake of anthracene or chrysene was higher than that of naphthalene, given the same concentration in the solution. In the absence of surfactant, the trend was similar, but the uptakes were increased by approximately 100% compared to those in the presence of surfactant. On the uptake of naphthalene, the presence of anthracene showed only minor influence. The uptake of anthracene was affected by both naphthalene and chrysene. The uptake of chrysene was influenced by neither naphthalene nor anthracene. There was no observable displacement of divalent cations from the surface of the gill membrane by any of the PAHs studied.

Use of biomarkers in Nile tilapia (Oreochromis niloticus) to assess the impacts of pollution in Bolgoda Lake, an urban water body in Sri Lanka

The present study reports the first analysis of water pollutants in Sri Lankan waters using a suite of biomarkers in Nile tilapia (Oreochromis niloticus) residing in Bolgoda Lake which receives urban, industrial and domestic wastes from multiple sources. The fish were collected from the lake in the dry period (April 2005) and wet periods (September 2005, October 2006) and the levels of biomarkers viz. hepatic ethoxyresorufin O-deethylase (EROD), glutathione S-transferase (GST), metallothioneins, biliary fluorescent aromatic compounds, brain and muscle cholinesterases (ChE) were compared with those of the laboratory reared control fish and the fish obtained from a less polluted water body, Bathalagoda reservoir (reference site). The results revealed that biomarker levels of the fish collected from the reference site were not significantly different from the controls. Hepatic EROD and GST activities in fish from Bolgoda Lake were induced 4.2-16.6 folds and 1.4-3.3 folds respectively compared with the control fish. Analysis of bile in the lake fish revealed recent uptake of naphthalene, pyrene and benzo(a)pyrene type polycyclic aromatic hydrocarbons (PAHs). The induction of EROD activities in feral fish reflects the exposure of fish to aryl hydrocarbon receptor agonists including PAHs present as pollutants in the Bolgoda Lake. Cholinesterase activity in the fish inhabiting one sampling site of Bolgoda Lake was lower (22-40% inhibition) than the activity measured in the control fish indicating the presence of anticholinesterase pollutants in the area. Hepatic metallothionein levels in the lake fish were higher (1.9-3.2 folds) in comparison to the controls indicating metal exposure. The results support the potential use of these biomarkers in Nile tilapia in assessing pollution in tropical water bodies.