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Metabolism of the polycyclic musk galaxolide and its interference with endogenous and xenobiotic metabolizing enzymes in the European sea bass (Dicentrarchus labrax)
2013
This study investigates the metabolism and mode of action of galaxolide (HHCB) in the European sea bass -Dicentrarchus labrax- following a single intraperitoneal injection of 50 mg HHCB/kg body weight. In addition, a group of fish was injected with 50 mg/kg of ketoconazole (KCZ), a fungicide that is known to interfere with different Cyp isoenzymes. HHCB was actively metabolised by sea bass and acted as a weak inhibitor of the synthesis of oxyandrogens in gonads of male fish. Both, HHCB and a hydroxylated metabolite were detected in bile. The fungicide ketoconazole was a strong inhibitor of Cyp11β and Cyp3a-catalyzed activities. The work contributes to the better understanding of the impact of synthetic musks on fish and proposes the determination of HHCB and/or its hydroxylated metabolite in bile as a tool to assess environmental exposure in wild fish.
Mostrar más [+] Menos [-]Incorporation and mineralization of TNT and other anthropogenic organics by natural microbial assemblages from a small, tropical estuary
2013
2,4,6-Trinitrotoluene (TNT) metabolism was compared across salinity transects in Kahana Bay, a small tropical estuary on Oahu, HI. In surface water, TNT incorporation rates (range: 3–121 μg C L−1 d−1) were often 1–2 orders of magnitude higher than mineralization rates suggesting that it may serve as organic nitrogen for coastal microbial assemblages. These rates were often an order of magnitude more rapid than those for RDX and two orders more than HMX. During average or high stream flow, TNT incorporation was most rapid at the riverine end member and generally decreased with increasing salinity. This pattern was not seen during low flow periods. Although TNT metabolism was not correlated with heterotrophic growth rate, it may be related to metabolism of other aromatic compounds. With most TNT ring-carbon incorporation efficiencies at greater than 97%, production of new biomass appears to be a more significant product of microbial TNT metabolism than mineralization.
Mostrar más [+] Menos [-]Phytoremediation of hexachlorocyclohexane (HCH)-contaminated soils using Cytisus striatus and bacterial inoculants in soils with distinct organic matter content
2013
Becerra-Castro, Cristina | Kidd, Petra S. | Rodríguez-Garrido, Beatriz | Monterroso, Carmela | Santos-Ucha, Paula | Prieto-Fernández, Ángeles
The performance of Cytisus striatus in association with different microbial inoculant treatments on the dissipation of the insecticide hexachlorocyclohexane (HCH) was studied. Two soils with different organic matter (A and B soil) content were spiked with 0 or 65 mg HCH kg−1. Plants were either not inoculated (NI), or inoculated with the endophyte Rhodococcus erythropolis ET54b and the HCH-degrader Sphingomonas sp. D4 separately or in combination (ET, D4 and ETD4). Unplanted pots were also established. HCH phytotoxicity was more pronounced in the B soil. Soil HCH concentrations in unplanted pots were similar to initial concentrations, whereas concentrations were reduced after plant growth: by 20% and 8% in A and B soil, respectively. Microbial inoculants also modified HCH dissipation, although effects were soil-dependent. Inoculation with the combination of strains (ETD4) led to a significant enhancement in HCH dissipation: up to 53% in the A soil and 43% in the B soil.
Mostrar más [+] Menos [-]Biodegradation of carbamate pesticides by natural river biofilms in different seasons and their effects on biofilm community structure
2013
Tien, Chien-Jung | Lin, Mon-Chu | Chiu, Wan-Hsin | Chen, Colin S.
This study investigated the ability of natural river biofilms from different seasons to degrade the carbamate pesticides methomyl, carbaryl and carbofuran in single and multiple pesticide systems, and the effects of these pesticides on algal and bacterial communities within biofilms. Spring biofilms had the lowest biomass of algae and bacteria but showed the highest methomyl degradation (>99%) and dissipation rates, suggesting that they might contain microorganisms with high methomyl degradation abilities. Degradation of carbofuran (54.1–59.5%) by biofilms in four seasons was similar, but low degradation of carbaryl (0–27.5%) was observed. The coexistence of other pesticides was found to cause certain effects on pesticide degradation and primarily resulted in lower diversity of diatoms and bacteria than when using a single pesticide. The tolerant diatoms and bacteria potentially having the ability to degrade test pesticides were identified. River biofilms could be suitable biomaterials or used to isolate degraders for bioremediating pesticide-contaminated water.
Mostrar más [+] Menos [-]Isosteric heats of sorption and desorption of phenanthrene in soils and carbonaceous materials
2013
Wang, Guohui | Grathwohl, Peter
Isosteric heats (ΔH) of sorption/desorption of phenanthrene were determined for carbonaceous materials (Pahokee peat, lignite, and high-volatile bituminous coal) and two soils based on reported equilibrium sorption/desorption isotherms at four different temperatures (4, 20, 46 and 77 °C). In addition, ΔH for desorption of native phenanthrene was determined to elucidate the “aging” effect by equilibrating samples with water at six temperatures (20, 40, 53, 61, 73, and 86 °C). Isosteric heats decreased with increasing solute concentration and were in a range of 19–35 kJ mol−1. Values higher than the heat of octanol–water phase transfer for phenanthrene (19 kJ mol−1) imply that both partitioning and adsorption processes are involved for these materials, where the sorptive contributions from both processes were estimated based on the phenanthrene thermodynamic data. Moreover, on the basis of ΔH values of desorption, release of native and spiked phenanthrene from our samples was similar.
Mostrar más [+] Menos [-]Social [and health] relevance of psychotropic substances monitoring in air
2013
Cecinato, Angelo | Balducci, Catia | Mollica, Roberto | Serpelloni, Giovanni
Drug abuse assessment methods based on measuring illicit substances in waste waters are consolidated. The approach of ambient air monitoring looks questionable, nonetheless it can be explored if the variables determining the drug burdens are accounted for, or suitable co-contaminants are adopted to normalize concentrations to environmental and human contours. The general approach linking the airborne drug concentrations to consumption is presented and the case of cocaine is discussed according to measurements conducted in Italy. The cocaine/nicotine concentration ratio, identified as the most suitable tool, fitted well with anti-drug Police operations and people noticed for drug-related crimes, and with the abuse prevalence estimated in the cities investigated. According to that, the conversion factors of drug concentrations into prevalence estimates seem assessable, provided sufficient databases over space and time are collected. Further investigations are necessary to understand if airborne drugs cause adverse sanitary effects.
Mostrar más [+] Menos [-]Monitoring bioremediation of atrazine in soil microcosms using molecular tools
2013
Sagarkar, Sneha | Mukherjee, Shinjini | Nousiainen, Aura | Björklöf, Katarina | Purohit, H. J. (Hemant J.) | Jørgensen, Kirsten S. | Kapley, Atya
Molecular tools in microbial community analysis give access to information on catabolic potential and diversity of microbes. Applied in bioremediation, they could provide a new dimension to improve pollution control. This concept has been demonstrated in the study using atrazine as model pollutant. Bioremediation of the herbicide, atrazine, was analyzed in microcosm studies by bioaugmentation, biostimulation and natural attenuation. Genes from the atrazine degrading pathway atzA/B/C/D/E/F, trzN, and trzD were monitored during the course of treatment and results demonstrated variation in atzC, trzD and trzN genes with time. Change in copy number of trzN gene under different treatment processes was demonstrated by real-time PCR. The amplified trzN gene was cloned and sequence data showed homology to genes reported in Arthrobacter and Nocardioides. Results demonstrate that specific target genes can be monitored, quantified and correlated to degradation analysis which would help in predicting the outcome of any bioremediation strategy.
Mostrar más [+] Menos [-]The importance of edaphic niches and pioneer plant species succession for the phytomanagement of mine tailings
2013
Parraga-Aguado, Isabel | Gonzalez-Alcaraz, Maria Nazaret | Alvarez-Rogel, Jose | Jimenez-Carceles, Francisco J. | Conesa, Hector M.
Phytomanagement in terms of phytostabilisation is considered a suitable method to decrease environmental risks of metal(loid) enriched mine tailings. The goal of this study was to identify plant-favourable edaphic niches in mine tailings from a semiarid area, in order to obtain relevant information for further phytostabilisation procedures. For this purpose, a transect-designed sampling from non-disturbed soils to two mine tailings was performed, including the description of soil and plant ecology gradients. Plant ecological indicators showed several stages in plant succession: from weeds to stable patches of late successional plant species. PCA results revealed that plant distribution at the tailings was driven mainly by salinity while metal(loid) concentrations played a minor role. The presence of soil desiccation cracks generated low salinity patches which facilitated favourable niches for plant establishment. Edaphic-patch distribution may condition phytostabilisation since ploughing or the employment of certain amendments should take into account favourable niches for plant growth.
Mostrar más [+] Menos [-]Ecotoxicity of non-aged and aged CeO2 nanomaterials towards freshwater microalgae
2013
Manier, Nicolas | Bado-Nilles, Anne | Delalain, Patrice | Aguerre-Chariol, Olivier | Pandard, Pascal
The ecotoxicity of artificially alterated cerium dioxide nanoparticles (nano-CeO2) suspensions was determined using the freshwater microalgae growth inhibition test. The agglomeration or aggregation state of the alterated suspensions was followed because it represents one of the obvious modifications when nanoparticles reached the environment. In addition, its influence on the ecotoxicity of nanoparticles is currently not well-addressed. Our results showed that the suspensions were stable within the first 24 h and then agglomerate up to 10 μm after 3 and 30 days. The inhibitory effect on the growth of exposed algae was however similar whatever the tested suspension. This supports the fact that the agglomeration state of nano-CeO2, in our conditions, has few influences on the ecotoxicity toward these organisms. The EC50 values were 5.6; 4.1 and 6.2 mg L−1, after exposure to non aged, 3 and 30 days aged suspensions respectively. The interaction between algal cells and nano-CeO2 was also addressed.
Mostrar más [+] Menos [-]Spatial distribution assessment of particulate matter in an urban street canyon using biomagnetic leaf monitoring of tree crown deposited particles
2013
Hofman, Jelle | Stokkaer, Ines | Snauwaert, Lies | Samson, Roeland
Recently, biomagnetic monitoring of tree leaves has proven to be a good estimator for ambient particulate concentration. This paper investigates the usefulness of biomagnetic leaf monitoring of crown deposited particles to assess the spatial PM distribution inside individual tree crowns and an urban street canyon in Ghent (Belgium). Results demonstrate that biomagnetic monitoring can be used to assess spatial PM variations, even within single tree crowns. SIRM values decrease exponentially with height and azimuthal effects are obtained for wind exposed sides of the street canyon. Edge and canyon trees seem to be exposed differently. As far as we know, this study is the first to present biomagnetic monitoring results of different trees within a single street canyon. The results not only give valuable insights into the spatial distribution of particulate matter inside tree crowns and a street canyon, but also offer a great potential as validation tool for air quality modelling.
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