Concentrations Of Phenanthrene Research Articles

Human health risks from fish consumption following a catastrophic gas oil spill in the Chiquito River, Veracruz, Mexico

An industrial accident resulted in a gas oil spill of 11,808 barrels in the upper part of the Coatzacoalcos River watershed. After river shore cleanup, concentrations of total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAH) in muscle (+ skin) were determined in captured fish to evaluate human health risk due to fish consumption post-spill in the most affected communities. Data on fish consumption, body weight, and diet factor were collected by questionnaires and field observations. Using standard formulas for carcinogenic and non-carcinogenic substances, site-specific remediation levels were calculated in fish, comparing them to the real levels observed. Likewise, the levels of PAHs in fish captured pre- and post-spill were compared to determine their origin (pyrolytic vs. petrogenic). The TPH concentrations were between 119,000 and 523,000 ng/g (dry weight) and no significant difference (P > 0.05) was found pre- vs. post-spill. The concentration of total PAHs varied between 2494.83 and 35,412.23 ng/g (dry weight), with the concentrations of naphthalene (520.9 ng/g) and phenanthrene (7532.7 ng/g) being much higher than in control samples, and being from the gas oil spill (petrogenic origin). The site-specific remediation levels calculated for TPH and PAH were much higher than the maximum levels actually detected. No human health risks were found from hydrocarbons from the spill, at least after cleanup efforts and natural attenuation (six months).

Vertical distribution of polycyclic aromatic hydrocarbons in the brackish sea water column: ex situ experiment.

BackgroundOil spills can cause severe damage within a marine ecosystem. Following a spill, the soluble fraction of polycyclic aromatic hydrocarbons is rapidly released into the water column. These remain dissolved in seawater over an extended period of time, even should the insoluble fraction be removed. The vertical distribution of the aromatic hydrocarbon component and how these become transferred is poorly understood in brackish waters. This study examines the vertical distribution of polycyclic aromatic hydrocarbons having been released from a controlled film of spilled oil onto the surface of brackish water.MethodsThe study was undertaken under controlled conditions so as to minimize the variability of environmental factors such as temperature and hydrodynamics. The distribution of polycyclic aromatic hydrocarbons was measured in the dissolved and suspended phases throughout the 1 m water column with different intensity of water sampling: 1, 2, 4, 7, 72, 120, 336, 504 and 984 h.ResultsThe total concentration of polycyclic aromatic hydrocarbons ranged from 19.01 to 214.85 ng L–1 in the dissolved phase and from 5.14 to 63.92 ng L–1 in the suspended phase. These hydrocarbons were released immediately following a controlled spill attaining 214.9 ng L–1 in the dissolved phase and 54.4 ng L–1 in the suspended phase near the cylinder bottom after 1–2 h. The 2–3 ring polycyclic aromatic hydrocarbons dominated in the dissolved phase (60–80%), whereas the greater amount of 4–6 ring polycyclic aromatic hydrocarbons (55–90%) occurred in the suspended phase. A relatively low negative correlation (rS = –0.41) was determined between the concentration of phenanthrene and suspended matter, whereas a high negative correlation (r = − 0.79) was found between the concentration of pyrene and suspended matter. Despite the differences in the relationships between the concentration ratio and amount of suspended matter the obtained regressions allow roughly to predict the concentration of polycyclic aromatic hydrocarbons.

Non-targeted metabolomics reveal the impact of phenanthrene stress on root exudates of ten urban greening tree species

Different root exudations can modify the bioavailability of persistent organic pollutants (POPs). Among these exudations, the low molecular weight organic acids play an imperative role in this process. The study was conducted to analyze the effect of phenanthrene (PHE) stress on root exudation variations and changes in its chemical composition in ten urban greening tree species, namely Loropetalum chinense, Gardenia ellis, Photinia fraseri, Ligustrum japonicum, Rhododendron simsii, Osmanthus fragrans, Gardenia jasminoides, Buxus sinica, Camellia sasanqua, and Euonymus japonicas. The experiment was carried out in three PHE concentration treatments (0 mg kg−1 (CK), 200 mg kg−1 (PHEL), 2000 mg kg−1 (PHEH)). The root exudates were collected and analyzed by GC-MS method. In total, 673 compounds were identified either with high or low abundance among all species and treatments. Compounds identified in CK, PHEL, and PHEH were 240, 180, and 256, respectively. The results illustrated that carbohydrates, phenols, and esters were the dominant compounds, accounted for more than 92%. Principal component analysis depicted that tree species grown in PHEH showed obvious alteration in compounds of root exudation, whereas little difference was noticed between PHEL and CK. Phenols (80%) were the most abundant, while nitriles contributed a small portion. Moreover, among all species, R. simsii released the maximum number of compounds, and L. japonicum released the least number of compounds accounting for 89 and 46, respectively. The results achieved here to illustrate that plant type, and PHE stress can significantly change the concentrations and species of root exudates. This study provides the scientific reference for understanding the phenanthrene responsive changes in root exudates and phytoremediation of polycyclic aromatic hydrocarbons (PAHs), as well as a screening of urban greening tree species.

Establishing the Order of Importance Factor Based on Optimization of Conditions in PAHs Biodegradation

In environmental study, optimization of different factors is crucial to obtain high removal of specific pollutants. The sequence of important factors that were considered in optimization studies is less concerned, and this part is crucial before proceeding to full-scale bioremediation study. This study focuses on bioremediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil with the potential bacteria, Corynebacterium urealyticum which is isolated from municipal sludge. The bacterial strain has evaluated the effectiveness of PAHs degradation at various factors on soil pH, soil temperature, initial PAHs concentration, initial bacteria number, and heavy metals concentration. The optimum condition for phenanthrene biodegradation was pH 7, 30 °C, 500 mg/kg of phenanthrene concentration, 109 cells/g soil, and without the addition of Zn. In establishing the ranking, we attempt to use a simple method based on the analysis of p values. Based on the analysis of degradation rates, the initial phenanthrene concentration shows the lowest p value, which means that it shows the highest ranking; the most significant factor to achieve highest degradation. In vice versa, the soil pH shows the highest ranking based on the analysis of bacteria growth rates, which is a very limited study that focuses on growth rates in the optimization study. The establishment of these rankings may reduce time, energy and cost in pilot or field study and at the same time achieve highest degradation in bioremediation work. Thus, it is highly recommended to develop the ranking before proceeding to design work in pilot and field study.

Toxic effects of phenanthrene intensify with an increase of temperature for the populations of a free-living nematode

Phenanthrene is one of the most common Polycyclic Aromatic Hydrocarbons (PAHs) in the marine environment. It has high lipoafinity and environmental persistence and tends to accumulate in benthic ecosystems. Exposure to phenanthrene can have severe impacts on a wide range of marine organisms, from nematodes to fish. These effects can be exacerbated with concurrent warming associated with climate change. In this study we investigated the response of free-living nematode populations of the species Diplolaimelloides delyi following exposure to different phenanthrene concentrations under normal and increased temperature conditions (from 25 °C up to 35 °C). Phenanthrene was toxic to D. delyi, causing a decrease in population growth (at concentrations ≥1 μg ml−1) and negatively affecting their development times and reproduction (at concentrations ≥2.5 μg ml−1). The observed effects intensified with increasing temperature, leading to further reduced development and population growth rate, arrested reproduction, and even mortality in 100% of the populations exposed to phenanthrene concentrations over 5 μg ml−1 at the highest temperature used (30 °C). Thermal-induced toxicity effects on marine populations can be significant, and current climate change and warming may have substantial implications for marine food webs and ecosystem functioning.

Earthworms and rice straw enhanced soil bacterial diversity and promoted the degradation of phenanthrene

BackgroundSince the industrial revolution, the contamination of agricultural soils by polycyclic aromatic hydrocarbons (PAHs) has increasingly become of serious global environmental concern and poses a huge threat to human beings and natural ecosystems. Microbial degradation is a proved technology mostly used to depollute polycyclic aromatic hydrocarbon (PAH) in the environment. However, very limited information is available regarding the interaction of earthworms with rice straw on the soil microbial community and the degradation of phenanthrene. This study was performed to enlighten the rice straw and earthworms’ interaction on soil bacterial abundance and structure and phenanthrene removal.ResultsResult about functional gene information revealed that both rice straw and earthworm enhanced phenanthrene degradation. Subsequently, both Shannon diversity index (r2 = − 0.8807, p < 0.001) and bacterial 16S rRNA genes (r2 = − 0.7795, p < 0.001) negatively correlated with the remaining phenanthrene concentration in soil. The application of both rice straw and earthworms in soil had the lowest ratio of soil remaining phenanthrene concentration (0.16 ± 0.02), the highest Shannon diversity index (6.45 ± 0.2) and the highest bacterial 16S rRNA genes. This implied that both earthworms and rice straw might improve the phenanthrene metabolism by increasing soil bacteria diversity. The abundance of genera Pseudomonas, Luteimonas, Rhodanobacter, Sphingomonas, Gemmatimonas, Flavobacterium, and Leifsonia was significantly increased in the presence of both earthworms and rice straw and was found to negatively correlate with the remaining phenanthrene concentration in soil.ConclusionBased on these results, this study offers clear and strong evidences that the positive interaction between earthworms and rice straw could promote phenanthrene degradation in soil. These finding will improve our understanding on the importance of the natural resources forsaken and how they can interact with the soil macro- and microorganisms to change soil structure and enhance PAH degradation in soil.

Size effects of microplastics on accumulation and elimination of phenanthrene in earthworms

Microplastics (MPs) are a class of emerging contaminants with diverse sizes. They influence the behavior of pollutants in the environment and cause harmful effects on organisms. To date, the size effects of MPs on the accumulation of organic pollutants by terrestrial invertebrates remain unclear. Here, we study the impacts and mechanisms of polystyrene MPs on the accumulation and elimination of phenanthrene in earthworms. Results showed that larger-size MPs (10 and 100 µm) facilitated the accumulation of phenanthrene by earthworms in the first week, whereas 100 nm MPs inhibited the elimination of phenanthrene in earthworms afterwards. Higher genotoxicity to earthworms was observed for co-exposure of micron-size MPs and phenanthrene, and 10 µm MPs were detected at the highest concentration and caused the most serious DNA damage to earthworm coelomocytes. Biomarkers and their mRNA gene expression levels suggested that larger-size MPs caused severer damage to earthworms, thus leading to increased accumulation of phenanthrene by earthworms at the beginning. Moreover, high-throughput 16S rRNA gene sequencing indicated that nano-size MPs significantly inhibited phenanthrene-degrading bacteria in earthworms, resulting in the highest residual concentration of phenanthrene. This study highlights the size effects of MPs and their impacts on the accumulation of organic pollutants by terrestrial organisms.

Exploration of the biotransformation processes in the biodegradation of phenanthrene by a facultative anaerobe, strain PheF2, with Fe(III) or O2 as an electron acceptor

The study of biodegradation of polycyclic aromatic hydrocarbons (PAHs) with metal ions as electron acceptors is still in its infancy. Here, a pure culture of PheF2 sharing 99.79% 16S rRNA-sequence similarity with Trichococcus alkaliphilus, which was recently reported to degrade PAHs, was isolated and found to degrade PAHs with Fe (III) or O2 reduction. Phenanthrene was selected as a model of PAH to study the biodegradation process by PheF2 with Fe (III) or O2 as an electron acceptor. PheF2 exhibited nearly 100%, 37.1%, and 28.5% anaerobic biodegradation of phenanthrene at initial concentrations of 280.7 μM, 280.6 μM, and 281.3 μM, respectively, within 10 days under anaerobic conditions with XAD-7 as a carrier, heptamethylnonane (HMN) as a solution, and nothing, respectively. PheF2 could degrade nearly 100% of the initial phenanthrene concentration of 283.4 μM under aerobic conditions within three days. The initial step of phenanthrene biodegradation by PheF2 involved carboxylation and dioxygenation under anaerobic and aerobic conditions, respectively. The biotransformation processes of phenanthrene degradation by PheF2 with Fe(III) or O2 as an electron acceptor were explored by metabolite and genome analysis. These findings provide an important theoretical support for evaluation of PAHs fate and for PAHs pollution control or remediation in anaerobic and aerobic environments.

Genotoxicity by Pahs In Shrimp (Litopenaeus Vannamei) and Its Impact on The Aquaculture of Two Coastal Ecosystems of The Gulf of California, Mexico

During the lasts decades, aquaculture of several species have growth vertiginously around the world. In Mexico the shrimp aquaculture has been the most important. About 73-75 % of shrimp hatcheries are in coastal ecosystems of the states of Sonora and Sinaloa, located along the Gulf of California. In this States there is not oil industry; however, several industries and other activities discharge petroleum derivatives (imprudently or accidentally) into coastal waters; as happens in Teacapan estuary and Huizache-Caimanero lagoon. The aim of this work was to quantify the levels of PAHs in water of these ecosystems, and to evaluate the genotoxic damage to shrimp, under laboratory conditions. Water samples were taken during rainy and dry months from both coastal systems, and then analyzed by Gas Chromatography (GC). Once known the PAHs concentrations, lots of seven juvenile shrimp were exposed to sub-lethal concentrations of Naphthalene, Phenanthrene, Chrysene, Fluorene, Anthracene, Pyrene, Fluoranthene, Benzo(b)fluoranthene and Benzo(a)pyrene during 21 days, since these were the most frequently PAHs found. At end of exposure period, genotoxicity was evaluated by Comet assay, and presence of micro-nucleus in shrimp haemocytes. Results demonstrated genotoxic damage by presence of comets, and micro-nucleus more frequently in exposed shrimps than controls. Also, a growth decrease was observed in exposed shrimps. These results, indicate potential risk for shrimp aquaculture in Sinaloa and human health, since shrimp is exported and consumed locally, and because in some cases, experimental PAHs concentrations were lower than concentrations of some PAHs found in water of Teacapan estuary and Huizache–Caimanero lagoon.&#x0D;

Study on the preparation of the hierarchical porous CX-TiO2 composites and their selective degradation of PHE solubilized in soil washing eluent

A series of CX-TiO2(Carbon Xerogel- TiO2) composites with a hierarchical porous structure were obtained through the sol-gel method followed by drying and carbonization, and have been applied to treating solubilizing wastewater containing a high concentration of phenanthrene (PHE). The characterizations demonstrated that the CX-TiO2 exhibits a hierarchical porous structure, with particles of carbon and P25 being uniformly in the matrix. Removal efficiency of CX-TiO2 on PHE in soil washing eluent (SWE) were evaluated under ultraviolet (UV) irradiation or dark condition, and P25 was employed as the reference. The results revealed that CX-TiO2(0.2) had the best removal effect on PHE, with the efficiency as high as 97.8% under UV illumination within 15 h. It demonstrated that in the process of PHE removal by CX-TiO2 whether it was under UV illumination or not, the adsorption plays a dominant role in the early stage. The kinetic behavior of PHE adsorption was fitted using the pseudo-first-order and pseudo-second-order, and Langmuir model and Freundlich models were applied to describe the PHE adsorption isotherms. The results indicating that it was a chemical adsorption process, which was influenced by the interaction between PHE and CX-TiO2, and PHE is adsorbed on the interface of CX-TiO2(0.2) in a single layer form, instead of agglomerating in the admicelle. A possible mechanism of removal of solubilized PHE in SWE was speculated, in which both hierarchical porous structure and appropriate micropores size of CX-TiO2 were indispensable to the selective adsorption and degradation of PHE. Recycling performance certificated that the selective removal efficiency of PHE could still reach 82.09% after five recycles. Thus the excellent performance testified that the CX-TiO2 have great potential in treating SWE containing solubilized PAHs.

Changes in microbial communities during phytoremediation of contaminated soil with phenanthrene.

Although polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants that affect negatively soils biology, several strategies lead to their removal such as the phytoremediation. In order to assess the potential of phytoremediation using "alfalfa" Medicago sativa as a strategy to reduce the phenanthrene on the soil, we analyzed the structure and dynamic of the microbial communities of a microcosm soil artificially contaminated with phenanthrene (2000ppm), which was exposed to the plants. At different incubation times (7, 14, 21, 28, 42, and 56days), a soil sample was taken from each microcosm and the residual amount of phenanthrene was quantified. Dehydrogenase activity and the count of fungi and bacteria were also estimated. Bacterial communities were characterized using PCR-DGGE, Shannon and Weaver's indexes, multivariate analysis, and rarefaction curves. It was found that phytoremediation treatment was associated with a higher richness and bacterial diversity compared with those on control soil. Although an OTUs (Operational Taxonomic Unit) succession over time was detected in both treatments, bacterial richness and diversity were conditioned by the phenanthrene concentration available and also dependent on the treatment, which were associated to different bacterial communities. In this study, phytoremediation treatment reduced the content of phenanthrene in the soil after 56days to a 0.45% compared with the control treatment, which only reached to 4.25%. This preliminary work suggests the promoting activity of "alfalfa" plants, through rhizodegradation, to remove in soil PAHs, as well as its relevance in the activation of different ecological processes mediated by soil microorganisms.

Correlation between cytochrome P450 1A (cyp1a) mRNA expression and ambient phenanthrene and pyrene concentration in Javanese Medaka Oryzias javanicus

Cytochrome P450 1A (Cyp1a) catabolizes polycyclic organic compounds. In this study, we sequenced the cyp1a gene from two Javanese medaka Oryzias javanicus strains and examined gene expression in response to two organic pollutants, phenanthrene and pyrene. Sequence comparisons among the two strains identified several single-nucleotide polymorphisms (SNPs), two of which resulted in amino acid substitutions. Reverse transcription PCR analysis of major organs revealed that the cyp1a mRNA level is highest in the liver. After determining LC50s against phenanthrene and pyrene for 96 h (3.9 and 2.5 µM, respectively), cyp1a mRNA expression in the liver against sublethal concentrations of phenanthrene and pyrene was examined. Using quantitative real-time PCR, a positive correlation was discovered between the cyp1a mRNA levels and pyrene concentration, and similar tendency was observed for phenanthrene. cyp1a may serve as a quantitative indicator of a broad range of pollutants.

Respuestas fisiológicas y capacidad antioxidante de &lt;i&gt;Chlorella vulgaris&lt;/i&gt; (Chlorellaceae) expuesta a fenantreno

Los hidrocarburos aromáticos tienen un alto potencial toxicológico, por lo que su evaluación en organismos acuáticos es de gran importancia. La microalga Chlorella vulgaris fue seleccionada, por ser una de las especies de algas más dominantes en el agua y por su potencial para degradar o absorber diferentes xenobióticos. El objetivo fue evaluar la toxicidad en C. vulgaris expuesta a fenantreno (PHE), evaluando parámetros fisiológicos como la densidad celular, contenido de clorofila a y clorofila b y actividad enzimática de superóxido dismutasa (SOD) y catalasa (CAT) que definan respuestas tóxicas a corto plazo. Se evaluaron cinco diferentes concentraciones (0,1; 1,0; 10; 100 y 1000 µg PHE. L-1), un tratamiento control solvente (acetona) y control (sin aditamentos) durante siete días. En todas las respuestas fisiológicas se observó un comportamiento dosis dependiente, disminuyendo progresivamente con el incremento de las concentraciones de PHE. La densidad celular, tasa de crecimiento, diámetro celular y clorofila pueden ser considerados biomarcadores de toxicidad. La actividad de CAT y SOD en C. vulgaris disminuyó considerablemente durante todo el periodo de estudio, posiblemente a causa de una excesiva producción de especies reactivas de oxígeno generadas por la exposición a fenantreno provocando la inhibición de estas enzimas antioxidantes. A pesar de la toxicidad de este hidrocarburo evidentemente observada en este estudio, C. vulgaris presenta una alta resistencia y adaptación a este contaminante, por lo que se puede decir que este microorganismo tiene la capacidad de evidenciar efectos toxicológicos en un entorno con este contaminante en un corto periodo de tiempo.

Teratogenic effects of environmentally relevant concentrations of phenanthrene on the early development of marine medaka (Oryzia melastigma)

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in marine environments and have arouse great concern since they pose adverse effects to marine ecosystem. To determine the potential impacts of environmentally relevant PAHs on early life stages of marine fish, this study exposed embryos of marine medaka (Oryzias melastigma) to 0, 2, 10, 50, and 250 μg/L of phenanthrene (Phe), one of the most abundant PAHs. The results demonstrated that Phe exposure decreased hatching rates, delayed hatching time of embryos, and increased deformity rate of newly-hatched larvae. Exposure to 10 and 50 μg/L Phe decreased the survival rate of marine medaka larvae at 28 days post-fertilization (dpf), and no embryo successfully hatched in 250 μg/L Phe exposure group. Morphology results showed that 10, 50, and 250 μg/L Phe exposure significantly retarded the development of embryos, and 2, 10, and 50 μg/L caused yolk sac edema and pericardial edema in newly-hatched larvae, indicating that low concentrations of Phe could induce developmental cardiac toxicity. Furthermore, the changes in the expression of heart development-related genes were determined, and the results showed that Phe-induced cardiac malformation might be related with fgf8, bmp4, smyd1, ATPase and gata4 genes. Overall, environmentally relevant PAHs could disrupt heart morphogenesis and hatching process of marine medaka, which might have profound consequences for sustainability of fish population.

Removal Efficiencies of Constructed Wetland Planted with Phragmites and Vetiver in Treating Synthetic Wastewater Contaminated with High Concentration of PAHs

This study aimed to evaluate the capability of horizontal subsurface flow constructed wetlands (HSFCWs) in treating contaminated wastewater with a high concentration of polycyclic aromatic hydrocarbons (PAHs) (Phenanthrene, Pyrene, and Benzo[a]Pyrene), using two plants, namely Phragmites and Vetiver. The investigated parameters were (1) PAHs uptake by the plants, (2) PAHs removal efficiencies, (3) accumulated PAHs in the soil of CWs, (4) shoot/root concentration factor, (5) translocation factor, and (6) PAHs correlation to lipid contains in the plants. During the treatment period, the results showed that the highest concentration of Phenanthrene in the shoot and the root systems of Phragmites, was 229.3 and 192 μg/g; Pyrene was 69.1 and 59.2 µg/g; and Benzo[a]Pyrene 25.1 and 20.2 µg/g, respectively. Meanwhile, in the Vetiver shoot and root systems were Phenanthrene 87.5 and 64.1 µg/g; Pyrene 63.2 and 42.1 µg/g; and Benzo[a]Pyrene 21.3 and 27.3 µg/g, respectively. The removal rates of Phenanthrene, Pyrene, and Benzo[a]Pyrene (PAHs compounds) by the CW planted with Phragmites were found to be 83%, 71%, and 81%, respectively, while the removal rates by CW planted with Vetiver were found to be 67%, 66%, and 73%, respectively. Moreover, the removal rates by unplanted CW were found to be 62%, 58%, and 55%, respectively. The results indicated that the HSFCW planted with Phragmites has an effective pathway to remove high concentrations of PAHs.

Formation and distribution of phenanthrene and its metabolites (monohydroxy-phenanthrenes) in Korean rockfish (Sebastes schlegelii)

This study investigated the tissue distribution of phenanthrene (PHE) and the formation of monohydroxy-phenanthrene (OH-PHE) metabolites in Korean rockfish (Sebastes schlegelii). PHE was intragastrically administered to two groups of rockfish. The first group was exposed to PHE at a low dose (10 mg/kg body weight) and the second group was exposed at a high dose (30 mg/kg body weight). The rockfish were analyzed and the levels of PHE were higher in the liver, followed by muscle, and then bile. PHE concentrations in the liver, muscle, and bile were 1.4–26, 0.10–2.01, and not detected (ND)–0.13 μg/g wet weight, respectively. All five monohydroxylated PHE metabolites (1-OH-PHE, 2-OH-PHE, 3-OH-PHE, 4-OH-PHE, and 9-OH-PHE) were detected only in bile. Among these OH-PHE metabolites, 3-OH-PHE was found at the highest concentration from all fish bile samples in both PHE exposure groups, indicating that regioselective OH-PHE formation occurs in rockfish and 3-OH PHE could be a good biomarker of exposure of Korean rockfish to PHE. Suspect screening analysis of the rockfish bile was performed by LC-QTOF/MS, and the formation of two OH-PHE-DNA adducts (thymine–OH–PHE and cytosine–OH–PHE) were identified in the bile sample collected 6 h after rockfish were exposed to the high PHE dose, indicating that OH-PHE metabolites may be toxic to fish. This is the first report on the formation characteristics of OH-PHE metabolites in rockfish and their use as biomarkers of exposure of rockfish to parent PHE.

Metals, n-Alkanes, Hopanes, and Polycyclic Aromatic Hydrocarbon in Sediments from Three Amazonian Streams Crossing Manaus (Brazil)

Pollution is increasing in the Amazon region and its real impact is still unclear. Since this region is of great interest to the global community, this study aimed to assess geochemical biomarkers and metals in sediments from three streams crossing Manaus, a Brazilian city of 2.1 million inhabitants located in the heart of the Amazon rainforest. The Mindu and Quarenta streams criss-cross the urban area of Manaus and receive domestic effluents from many heavily populated districts. In addition, the Quarenta stream is subjected to effluents from the industrial district of Manaus. The Tarumã-Açu stream is mostly covered by vegetation, although the region presents some occurrence of family farming, floating petrol station, marinas, and floating restaurants and bars. n-Alkanes were determined by Gas Chromatography with Flame Ionization Detection (GC-FID), whereas hopanes and polycyclic aromatic hydrocarbons (PAHs) were determined by Gas Chromatography coupled to Mass Spectrometry (GC-MS). The metals Ag, Cd, Cr, Co, Cu, Mn, Ni, Pb, and Zn were determined by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) after microwave-assisted acid digestion. Concentrations of total PAHs and metals were higher in sediments from the urban streams Mindu and Quarenta because of the occurrence of more intense and diverse sources of pollution. In addition, some sediment samples from both these streams presented concentrations of fluoranthene, phenanthrene, and metals higher than the limits of low probability of adverse effects on biota established by the international guideline and by the Brazilian legislation. A similar total n-alkane concentration for sediments from all streams associated with profiles of n-alkanes with no odd/even hydrocarbon predominance suggests that biomass burning is an important source of hydrocarbons. Petroleum-derived products also represented a source for n-alkanes, as confirmed by the presence of α,β-hopanes, including an α,β-homohopane series from C31 to C35 with the presence of both 22S and 22R epimers. This is the first report on n-alkanes, PAHs, and hopanes in sediments from the Mindu, Quarenta, and Tarumã-Açu streams. The concentrations reported herein may be considered as baseline data in future monitoring programs of these streams.

Phenanthrene alters oxidative stress parameters in tadpoles of Euphlyctis cyanophlyctis (Anura, Dicroglossidae) and induces genotoxicity assessed by micronucleus and comet assay.

Phenanthrene (PHE), a tricyclic polycyclic aromatic hydrocarbon (PAH), is ubiquitously found in aquatic environments. It is one of the major components in PAH mixtures. It has been identified as one of the 16 priority PAHs for toxicological evaluations. PHE is reported to induce lethal and sub-lethal toxicity in various aquatic indicator organisms. However, no toxicological data of PHE in anuran amphibians could be found. Amphibian larvae (tadpoles) develop in aquatic habitats. Therefore, exposure to PHE could negatively impact their development and fitness in later periods as they move in to the terrestrial habitat following metamorphosis. In the present study, we have analyzed the effects of PHE in Euphlyctis cyanophlyctis tadpoles. PHE induced concentration-dependent lethal effects in the tadpoles. The estimated LC50 values were 16.52, 15.29, 13.69, and 12.28mg/L at 24, 48, 72, and 96h of exposure respectively. These LC50 values are significantly higher than the reported environmental concentration of PHE. However, the strong negative correlation (R2 = 0.997, p < 0.001) between the LC50 value and exposure time indicates that longer exposure to lower concentration may cause significant lethal effects. Besides, PHE at environmentally relevant concentrations induced significant sub-lethal toxicities. Exposure to sub-lethal concentrations was found to be genotoxic in erythrocyte micronucleus as well as comet assays. Sub-lethal concentrations of PHE significantly increased superoxide dismutase activity and tissue glutathione level as well as induced lipid peroxidation. The present findings clearly indicate that PHE is a potential threat to the early life stages of amphibians. Further investigations are necessary to ascertain the implications of these early effects during adult life stages.

Uptake and Distribution of Phenanthrene and Pyrene in Roots and Shoots of Wheat (Triticum aestivum L.)

Uptake, translocation and accumulation of phenanthrene and pyrene by wheat were studied under controlled conditions. Seeds were cultivated in perlite containing 300 mg kg−1 of phenanthrene and pyrene separately, and plants were grown hydroponically for 25 days. Sampling was performed every five days, and PAHs concentrations in roots and shoots of plants were determined using high-performance liquid chromatography (HPLC). The results revealed that phenanthrene naturally exists in wheat, and its concentration in roots was higher than that in shoots. Phenanthrene concentration in the roots was increased during the first 10 days and then was decreased until the 25th day, but its concentration in the shoots generally was decreased during the treatment period. In comparison, pyrene concentration was increased in roots and decreased in shoots during the treatment period. Although pyrene had higher uptake rate than phenanthrene in wheat roots, translocation factor of phenanthrene was higher than that of pyrene. According to the obtained results, phenanthrene can be metabolized in wheat especially in the shoots, but pyrene tends to be accumulated in roots.

Accumulation of 13C-labelled phenanthrene in phytoplankton and transfer to corals resolved using cavity ring-down spectroscopy.

Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants in marine ecosystems including threatened and potentially sensitive coral reefs. Lower organisms such as phytoplankton, known to bioconcentrate PAHs, could serve as potential entry points for these chemicals into higher trophic levels. Here, we present a novel method using a 13C-labelled PAH and cavity ring-down spectroscopy (CRDS) to investigate accumulation, uptake rates and trophic transfer of PAHs in corals, which are key organisms to sustain biodiversity in tropical seas. We quantified the accumulation of 13C-phenanthrene in the marine microalga Dunaliella salina, and in the coral Acropora millepora after diffusive uptake from seawater or dietary uptake via labelled D. salina. Additionally, we monitored the photophysiological health of D. salina and A. millepora during phenanthrene exposure by pulse-amplitude modulation (PAM) fluorometry. Dose-dependent accumulation of 13C-phenanthrene in the microalga showed a mean bioconcentration factor (BCF) of 2590±787Lkg-1 dry weight. Corals accumulated phenanthrene from both exposure routes. While uptake of 13C-phenanthrene in corals was faster through aqueous exposure than dietary exposure, passive diffusion showed larger variability between individuals and both routes resulted in accumulation of similar concentrations of phenanthrene. The 13C-PAH labelling and analysis by CRDS proved to be a highly sensitive method. The use of stable isotopic label eliminated additional toxicity and risks by radioactive isotopic-labelling, and CRDS reduced the analytical complexity of PAH (less biomass, no extraction, fast analysis). The simultaneous, precise quantification of both carbon content and 13C/12C ratio (δ13C) enabled accurate determination of 13C-phenanthrene accumulation and uptake rate. This is the first study to provide empirical evidence for accumulation of phenanthrene in a phytoplankton-coral food chain.