Search

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that continue to attract researchers' attention until these days due to their toxicity and their multisource emission. In this study, levels of 17 active molecules of PAHs were investigated in marine and continental Lebanese aquatic systems. The results showed that Lebanese seawater is more contaminated than several other sites on the Mediterranean Sea. On the marine side, the total concentration of PAHs ranges from 55.7 to 2683.8 ng L−1 in water and from 19.09 to 2025.03 ng g−1 in sediments. On the continental side, the total concentration ranges from 465.7 to 1399.9 ng L−1 in water and from 72.6 to 1074.7 ng g−1 in sediments presenting higher contamination and detection frequency than the marine sites. Pearson test was applied to determine the preference of PAHs toward one of the phases and showed that when the number of rings, the molecular mass and the log Ko/w increase, PAHs accumulate in sediments, and when the water solubility and the vapor pressure of PAHs increase, they tend to remain in the aqueous phase. Moreover, PAHs in Lebanese sediments were combustion-originated and resulted mainly from industrial sites set next to aquatic systems and heavy traffic especially along the Lebanese coastline. Regarding the toxicity effect, the use of the ERL/ERM approach revealed that few sites have individual PAHs levels that may occasionally cause biological adverse effects to benthic organisms; nevertheless, the ecosystem risk of PAHs in Lebanese sediments is low. [ABSTRACT FROM AUTHOR]

The increase use of pharmaceutical compounds in veterinary practice and human population results in the ubiquitous presence of these compounds in aquatic ecosystems. Because pharmaceuticals are highly bioactive, there is concern about their toxicological effects in aquatic organisms. Therefore, the aim of this study was to assess the effects of an effluent from a psychiatric hospital (containing a complex mixture of 25 pharmaceutical compounds from eleven therapeutic classes) on the freshwater clam Corbicula fluminea using a proteomic approach. The exposure of C. fluminea to this complex effluent containing anxiolytics, analgesics, lipid regulators, beta blockers, antidepressants, antiepileptics, antihistamines, antihypertensives, antiplatelets and antiarrhythmics induced protein changes after 1 day of exposure in clam gills and digestive gland more evident in the digestive gland. These changes included increase in the abundance of proteins associated with structural (actin and tubulin) , cellular functions (calreticulin, proliferating cell nuclear antigen (PCNA), T complex protein 1 (TCP1)) and metabolism (aldehyde dehydrogenase (ALDH), alcohol dehydrogenase, 6 phosphogluconate dehydrogenase). Results from this study indicate that calreticulin, PCNA, ALDH and alcohol dehydrogenase in the digestive gland and T complex protein 1 (TCP1)) and 6 phosphogluconate dehydrogenase in the gills represent useful biomarkers for the ecotoxicological characterization of psychiatric hospital effluents in this species. [ABSTRACT FROM AUTHOR]

Assessment of exposure and effect of fish to pharmaceuticals that contaminate aquatic environment is a current major issue in ecotoxicology and there is a need to develop specific biological marker to achieve this goal. Benzyloxy-4-trifluoromethylcoumarin-O-debenzyloxylase (BFCOD) enzymatic activity has been commonly used to monitor CYP3A activity in fish. In this study, we assessed the capacity of a panel of toxicologically relevant chemicals to modulate BFCOD activity in fish, by using in vitro and in vivo bioassays based on fish liver cell lines (PLHC-1, ZFL, RTL-W1) and zebrafish embryos, respectively. Basal BFCOD activity was detectable in all biological models and was differently modulated by chemicals. Ligands of human androgens, glucocorticoids, or pregnanes X receptors (i.e., dexamethasone, RU486, rifampicin, SR12813, T0901317, clotrimazole, ketoconazole, testosterone, and dihydrotestosterone) moderately increased or inhibited BFCOD activity, with some variations between the models. No common feature could be drawn by regards to their capacity to bind to these receptors, which contrasts with their known effect on mammalian CYP3A. In contrast, dioxins and polycyclic aromatic hydrocarbons (PAHs) strongly induced BFCOD activity (up to 30-fold) in a time- and concentration-dependent manner, both in vitro in all cell lines and in vivo in zebrafish embryos. These effects were AhR dependent as indicated by suppression of induced BFCOD by the AhR pathway inhibitors 8-methoxypsoralen and α-naphthoflavone. Altogether our result further question the relevance of using liver BFCOD activity as a biomarker of fish exposure to CYP3A-active compounds such as pharmaceuticals. [ABSTRACT FROM AUTHOR]

The nitrifying/denitrifying activated sludge process removes several micropollutants from wastewater by sorption onto sludge and/or biodegradation. The objective of this paper is to propose and evaluate a lab-scale experimental strategy for the determination of partition coefficient and biodegradation constant for micropollutant with an objective of modelling their removal. Four pharmaceutical compounds (ibuprofen, atenolol, diclofenac and fluoxetine) covering a wide hydrophobicity range (log K from 0.16 to 4.51) were chosen. Dissolved and particulate concentrations were monitored for 4 days, inside two reactors working under aerobic and anoxic conditions, and under different substrate feed conditions (biodegradable carbon and nitrogen). We determined the mechanisms responsible for the removal of the target compounds: (i) ibuprofen was biodegraded, mainly under aerobic conditions by cometabolism with biodegradable carbon, whereas anoxic conditions suppressed biodegradation; (ii) atenolol was biodegraded under both aerobic and anoxic conditions (with a higher biodegradation rate under aerobic conditions), and cometabolism with biodegradable carbon was the main mechanism; (iii) diclofenac and fluoxetine were removed by sorption only. Finally, the abilities of our strategy were evaluated by testing the suitability of the parameters for simulating effluent concentrations and removal efficiency at a full-scale plant. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants that can be present at high levels as mixtures in polluted aquatic environments. Many PAHs are potent mutagens and several are well-known carcinogens. Despite numerous studies on individual compounds, little is known about the toxicity of PAHs mixtures that are encountered in environmental situations. In the present work, zebrafish were continuously fed from 5 days post-fertilisation to 14 months post-fertilisation (mpf) with a diet spiked with fractions of either pyrolytic (PY), petrogenic light oil (LO), or petrogenic heavy oil (HO) origin at three concentrations. A decrease in survival was identified after 3 mpf in fish fed with the highest concentration of HO or LO, but not for PY. All PAH fractions caused preneoplastic and neoplastic disorders in long-term-exposed animals. Target tissues were almost exclusively of epithelial origin, with the bile duct epithelium being the most susceptible to chronic exposure to all PAH fractions, and with germ cells being the second most responsive cells. Significantly higher incidences of neoplasms were observed with increasing PAH concentration and exposure duration. The most severe carcinogenic effects were induced by dietary exposure to HO compared to exposure to LO or PY (45, 30 and 7 %, respectively, after 9 to 10 months of exposure to an intermediate concentration of PAHs). In contrast, earliest carcinogenic effects were detected as soon as 3 mpf after exposure to LO, including the lowest concentration, or to PY. PAH bioactivation and genotoxicity in blood was assessed by ethoxyresorufin- O-deethylase activity quantification and comet and micronuclei assays, respectively, but none of these were positive. Chronic dietary exposure of zebrafish to PAH mixtures results in carcinogenotoxic events that impair survival and physiology of exposed fish. [ABSTRACT FROM AUTHOR]

Xenobiotics such as pesticides and pharmaceuticals are an increasingly large problem in aquatic environments. A fixed-bed adsorption filter, used as tertiary stage of sewage treatment, could be a solution to decrease xenobiotics concentrations in wastewater treatment plants (WWTPs) effluent. The adsorption efficiency of two mineral adsorbent materials (expanded clay (EC) and zeolite (ZE)), both seen as a possible alternative to activated carbon (AC), was evaluated in batch tests. Experiments involving secondary treated domestic wastewater spiked with a cocktail of ten xenobiotics (eight pharmaceuticals and two pesticides) known to be poorly eliminated in conventional biological process were carried out. Removal efficiencies and partitions coefficients were calculated for two levels of initial xenobiotic concentration, i.e, concentrations lower to 10 μg/L and concentrations ranged from 100 to 1,000 μg/L. While AC was the most efficient adsorbent material, both alternative adsorbent materials showed good adsorption efficiencies for all ten xenobiotics (from 50 to 100 % depending on the xenobiotic/adsorbent material pair). For all the targeted xenobiotics, at lower concentrations, EC presented the best adsorption potential with higher partition coefficients, confirming the results in terms of removal efficiencies. Nevertheless, Zeolite presents virtually the same adsorption potential for both high and low xenobiotics concentrations to be treated. According to this first batch investigation, ZE and EC could be used as alternative absorbent materials to AC in WWTP. [ABSTRACT FROM AUTHOR]

The main objective of this study was to collect new data on the occurrence, levels of priority and emerging organic compounds in freshwater fish sampled in the Rhone River. The 34 studied contaminants included alkylphenols, bisphenol A, polybromodiphenylethers (PBDE), perfluorinated compounds, hexabromocyclododecanes (HBCD), hexachlorobenzene and hexachlorobutadiene (HCBD). About 50 fish samples (individual specimens or pooled fish) were collected from three sites located upstream and downstream of the Lyon metropolitan area in the Rhone River (France). Four species were caught at each site, namely: the barbel ( Barbus barbus), the common bream ( Abramis brama), the white bream ( Blicca bjoerkna) and the chub ( Squalius cephalus). Some contaminants were quantified in all the 32 fish samples analysed: 4-nonylphenol, α-HBCD, the six PBDE congeners (28, 47, 99, 100, 153, 154), perfluorooctanesulfonate (PFOS) and perfluorodecanoic acid. Twenty three of the 32 samples had a concentration of PFOS above the Environmental Quality Standards (EQS) (up to six times higher than the EQS), and all the 32 samples had concentrations of PBDE above the EQS (up to 4,000 times higher, with the sum of six PBDE varying from 4.5 to 182 ng/g dry weight). Clearly, the interest to consider PFOS and HBCD as new priority substances is confirmed. In contrast, the pertinence of a priority status for HCBD, which was never quantified in our study, might have to be reconsidered in the future. [ABSTRACT FROM AUTHOR]

Recent evidence suggests that polychlorinated biphenyls might also have adverse reproductive, developmental and endocrine effects. Although, the use of polychlorobiphenyls in Algeria has been banned for more than two decades, large quantities of these compounds containing products remain disseminated, mainly stored in obsolete or damaged equipments. This research describes a study to assess polychlorinated biphenyls distribution in marine sediments collected from the seaside of Tamentfoust touristic resort located in the eastern side of Algiers Bay. After microwave-assisted extraction and purification with both concentrated sulphuric acid and activated silica gel, the extracts were analyzed by gas chromatography with an electron capture detector. Relatively high contamination levels of polychlorinated biphenyls were found in samples collected from the port of Tamentfoust (15 to 70 ng/g d.w.), while the concentrations were lower in the stations located outside the port (0 to 26 ng/g d.w.). Compared with data previously reported by some other researchers, the polychlorobiphenyls concentrations found in this work showed an environmental persistence, but a decrease of approximately 5 times in 30 year i.e since the ban of the use of polychlorinated biphenyls. The predominant polychlorinated biphenyls congeners in all sediment samples were polychlorinated biphenyls138, 153, 180 and 187. This composition was similar to industrial mixture (Aroclor 1260). This probably indicated that the contamination originated from the port and has a continental source. [ABSTRACT FROM AUTHOR]

This paper describes fast and simple extraction methods for the determination of polychlorinated biphenyls and polybrominated diphenyl ethers in biological matrices. Four extraction protocols were tested. The first protocol used microwave-assisted extraction combined with two purification steps. The second one was similar, except that microwave-assisted extraction was replaced by accelerated solvent extraction. The third one combined extraction/purification by accelerated solvent extraction with final purification on a silica gel column. The last one combined microwave-assisted extraction with purification on an acidic silica gel column. The protocols were tested on various matrices: a spiked matrix, two certified matrices (SRM 2977, WMF 01), and natural matrices (mysids and fish). All of the protocols produced good performance in terms of recovery and reproducibility. The two last protocols showed promising results in terms of applicability to natural matrices, as they required a minimum of sample handling and minimal amounts of solvent and time. These methods allowed at least 24 samples to be handled per day, and could easily be used for routine analysis. [ABSTRACT FROM AUTHOR]

An analytical procedure for the simultaneous determination of twelve endogenous steroids (testosterone, androstenedione, 17β-estradiol, estrone, pregnenolone, progesterone, dihydroandrostenedione, dihydrotestosterone, 11α-ketotestosterone, 17α-hydroxyprogesterone, 17α-hydroxypregnenolone, 17α,20β-dihydroxy-4-pregnen-3-one) in plasma and bile samples by solid-phase extraction (SPE) and gas chromatography/mass spectrometry (GC–MS) has been developed. After enzymatic hydrolysis for bile samples only, samples were concentrated and purified using two successive SPE (C18 and NH2) cartridges. Analytes were derivatized with a mixture of N-methyl- N-(trimethylsilyl)trifluoroacetamide (MSTFA) / mercaptoethanol / ammonium iodide (NH4I) and determined by GC–MS in selective ion monitoring mode. For most of the steroids monitored, recoveries were in the range 90–120% in plasma and in the range 60–70% in bile, and the reproducibility was below 10% for the complete procedure. Limits of detection obtained ranged from 0.1 to 0.4 ng/g in fish plasma and from 1.6 to 14 ng/g in fish bile. The developed method was successfully applied to the determination of plasma steroids in flounders ( Platichthys flesus) collected from two French estuaries. [ABSTRACT FROM AUTHOR]

Using a conditioned proboscis extension response (PER) assay, honeybees (Apis melliferaL.) can be trained to associate an odor stimulus with a sucrose reward. Previous studies have shown that observations of conditioned PER were of interest for assessing the behavioral effects of pesticides on the honeybee. In the present study, the effects of sublethal concentrations of nine pesticides on learning performances of worker bees subjected to the PER assay were estimated and compared. Pesticides were tested at three concentrations. The highest concentration of each pesticide corresponded to the median lethal dose value (48-h oral LD50), received per bee and per day, divided by 20. Reduced learning performances were observed for bees surviving treatment with fipronil, deltamethrin, endosulfan, and prochloraz. A lack of behavioral effects after treatment with ? -cyalothrin, cypermethrin, t -fluvalinate, triazamate, and dimethoate was recorded. No-observed-effect concentrations (NOECs) for the conditioned PER were derived for the studied pesticides. Our study shows that the PER assay can be used for estimating sublethal effects of pesticides on bees. Furthermore, comparisons of sensitivity as well as the estimation of NOECs, useful for regulatory purposes, are possible. [ABSTRACT FROM AUTHOR]

Strain Sphingomonas sp. (2MPII), isolated from marine sediment, was able to utilize phenanthrene (P) or 2-methylphenanthrene (2MP) as the sole carbon source. However, 9-methylphenanthrene (9MP) and dibenzothiophene (DBT) were weakly degraded. The degradation rates of 9MP and DBT increased in the presence of 2MP, whilst the degradation rate of 2MP increased in the presence of 9MP. However, the presence of DBT inhibited the degradation of 2MP. DBT sulfone, a DBT metabolite, was not assimilated by the bacteria and its presence also decreased the degradation rate of 2MP. [ABSTRACT FROM AUTHOR]

A microwave-assisted protocol has been developed using focussed microwaves at atmospheric pressure for the extraction of PAHs and PCBs from sediments. It combines extraction and purification assisted by microwaves. This protocol has been applied to the quantification of 12 individual PAHs, 8 individual PCBs and 8 PCB coeluted mixtures from two Standard Reference Materials and one natural sediment. The results for both classes of compounds (PAHs and PCBs) are good in terms of recoveries, which are always greater than 70% and in most cases around 100%. The reproducibility is also good with coefficients of variation below 10% in most cases. This protocol has the great advantage of saving time, the time dedicated to the preparation / extraction assisted by microwaves being reduced to less than half an hour. [ABSTRACT FROM AUTHOR]

The Focused Microwave (FMW) assisted extraction for organic contaminant analysis, such as polycyclic aromatic hydrocarbons (PAHs), in environmental matrices, was studied and optimized using a factorial design. The effects and interactions of five parameters on the extraction recovery were investigated in a few experiments with a good accuracy: irradiation power and time, volume and nature of solvent, and percentage of moisture of the matrix. The results show that the percentage of water added to the freeze-dried matrix can significantly increase the extraction recovery. The irradiation power has also a positive effect. The choice of solvent is significant: a mixture of heptane/ethanol (80/20, v/v) allows better results than dichloromethane. Some interactions between percentage of moisture and the two previous parameters have been demonstrated: the effect of power and nature of solvent depends on the water content. Some optimal conditions have been established: 10 mL of heptane/ethanol (80/20, v/v), extraction time of 2 min, and different possible pairs of moisture content and irradiation power (140 W and 0% of moisture or 20 W and 40% of moisture) according to the need and wish of the experimentalist; or 10 mL of dichloromethane, extraction time of 2 min, 20 W and 40% of moisture. These optimized conditions provide very good recoveries compared to conventional extraction such as Soxhlet (near 100%) for the model matrix (a marine sediment) used for the factorial design. FMW extraction is a good alternative to Soxhlet extraction with reduction of time and reduction of solvent volume. This study shows that it is possible to substitute chlorinated solvent by a less toxic solvent, like a mixture of heptane and ethanol. [ABSTRACT FROM AUTHOR]

A rapid, selective and sensitive procedure for the analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in biological organisms has been developed and validated. The freeze-dried tissues were digested in ethanolic KOH. After solvent partitioning, the extract was purified on alumina and silica micro-columns and finally analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The final extract was free of most of the endogenous compounds. A quality assurance/quality control (QA/QC) was carried out. The absolute loss of the target compounds at different stages of the analytical procedure and during all of the procedure was estimated (losses<45%). The recoveries of PAHs were estimated using a certified standard compound solution (recoveries>90%) and spiked mussels (recoveries=100±6%). For validation a certified reference material mussel tissue (recoveries= 90±16%) was analyzed. [ABSTRACT FROM AUTHOR]

A marine bacterium isolated from a coastal hydrocarbon-polluted sediment has been described and attributed on the basis of its phenotypic and genotypic characteristics to the genus Sphingomonas sp. This strain was capable of using an alkylated phenanthrene 2-methylphenanthrene, as sole source of carbon and energy. In experiments, 2-methylphenanthrene (0.2 g/l) was added as crystals to the culture medium. After 5 days of aerobic growth at 30 °C, 70% was degraded and the complete dissipation occurred after 20 days. Furthermore, the strain could degrade various kinds of polyaromatic compounds, but failed to grow on aliphatic hydrocarbons. [ABSTRACT FROM AUTHOR]

Investigates the presence of micropollutants in the Gironde estuary, France. Presence of metallic and organic pollutants; Examination of sediments as a source of pollutants for the biota; Estimation of Cd mobility.