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11.
There may be important biological sources of polycyclic aromatic hydrocarbons (PAHs) to the global environment, particularly of naphthalene, phenanthrene, and perylene, that originate in the tropics. We (i) studied the distribution of PAHs among different compartments of a typical Cerrado to locate their sources and (ii) quantified the PAH storage of this ecosystem. The sum of 20 PAH (sigma20PAHs) concentrations ranged from 25 to 666 microg kg(-1) in plant tissue, 7.4 to 32 microg kg(-1) in litterfall, 206 to 287 microg kg(-1) in organic soil, and 10 to 79 microg kg(-1) in mineral soil. Among the living biomass compartments, the bark had the highest mean PAH concentrations and coarse roots the lowest, indicating that PAHs in the plants originated mainly from aboveground sources. Naphthalene and phenanthrene were the most abundant individual PAHs, together contributing 33 to 96% to the sigma20PAHs concentrations. The total storage of the X20PAHs in Cerrado was 7.5 mg m(-2) to a 0.15-m soil depth and 49 mg m(-2) to a 2-m soil depth. If extrapolated to the entire Brazilian Cerrado region, roughly estimated storages of naphthalene and phenanthrene correspond to 7300 and 400 yr of the published annual emissions in the United Kingdom, respectively. The storage of benzo[a]pyrene, a typical marker for fossil fuel combustion, in the Cerrado only corresponds to 0.19 yr of UK emissions. These results indicate that the Brazilian savanna comprises a huge reservoir of naphthalene and phenanthrene originating most likely from the aboveground parts of the vegetation or associated organisms. Thus, the Cerrado might be a globally important source of these PAHs. 相似文献
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13.
Juliane Ventura-Lima Daniele Fattorini José M. Monserrat 《Environmental pollution (Barking, Essex : 1987)》2009,157(12):3479-3484
Differences in the toxicological and metabolic pathway of inorganic arsenic compounds are largely unknown for aquatic species. In the present study the effects of short-time and acute exposure to AsIII and AsV were investigated in gills and liver of the common carp, Cyprinus carpio (Cyprinidae), measuring accumulation and chemical speciation of arsenic, and the activity of glutathione-S-transferase omega (GST Ω), the rate limiting enzyme in biotransformation of inorganic arsenic. Oxidative biomarkers included antioxidant defenses (total glutathione-S-transferases, glutathione reductase, glutathione, and glucose-6-phosphate dehydrogenase), total scavenging capacity toward peroxyl radicals, reactive oxygen species (ROS) measurement and lipid peroxidation products. A marked accumulation of arsenic was observed only in gills of carps exposed to 1000 ppb AsV. Also in gills, antioxidant responses were mostly modulated through a significant induction of glucose-6-phosphate dehydrogenase activity which probably contributed to reduce ROS formation; however this increase was not sufficient to prevent lipid peroxidation. No changes in metal content were measured in liver of exposed carps, characterized by lower activity of GST Ω compared to gills. On the other hand, glutathione metabolism was more sensitive in liver tissue, where a significant inhibition of glutathione reductase was concomitant with increased levels of glutathione and higher total antioxidant capacity toward peroxyl radicals, thus preventing lipid peroxidation and ROS production. The overall results of this study indicated that exposure of C. carpio to AsIII and AsV can induce different responses in gills and liver of this aquatic organism. 相似文献
14.
Christian W. Götz Christian Stamm Kathrin Fenner Heinz Singer Michael Schärer Juliane Hollender 《Environmental science and pollution research international》2010,17(2):341-354
Background, aim, and scope
Aquatic microcontaminants (MCs) comprise diverse chemical classes, such as pesticides, biocides, pharmaceuticals, consumer products, and industrial chemicals. For water pollution control and the evaluation of water protection measures, it is crucial to screen for MCs. However, the selection and prioritization of which MCs to screen for is rather difficult and complex. Existing methods usually are strongly limited because of a lack of screening regulations or unavailability of required data. 相似文献15.
Microarthropods are known as vectors for soil microorganisms, predominantly fungi. This laboratory study uses the widespread unicellular green algae Chlorella vulgaris as model to assess the role of Collembola in algal dispersal and to determine the effects of gut passage on propagation. Living algal cells were observed in 70 % of the faecal pellets of Folsomia candida, Heteromurus nitidus and Protaphorura fimata. Moreover, marker fatty acids for green algae, i.e. 16:2ω6,9 and 16:3ω3,6,9, were consistently detected in the pellets. Compared to the algal diet, the high content of methyl-branched total lipid fatty acid (TLFA) with hydroxyl substitution indicated microbial colonisation during gut passage. The TLFA profile of faeces revealed no species-specific differences but similar changes in microbial communities over the duration of feeding, indicating comparable indigenous bacteria and colonisation mechanisms during gut passage. In sum, faecal pellets of soil microarthropods such as Collembola can act as a vector for both dietary algae and specific gut-associated microorganisms, with the latter likely involved in resource degradation inside and outside the gut habitat. 相似文献
16.
Vetterlein D Szegedi K Ackermann J Mattusch J Neue HU Tanneberg H Jahn R 《Journal of environmental quality》2007,36(6):1811-1820
Arsenate (As V) is the predominant form of arsenic in soils under aerobic conditions and competes with the major plant nutrient phosphorus (P) in the form of phosphate (PV) not only for sorption sites on mineral surfaces in soil but also for root membrane transporters. Plants have evolved several mechanisms for the mobilization of PV in soils in response to P deficiency, such as the release of organic anions and protons. The aim of the present study was to test whether these mechanisms result in a simultaneous mobilization of arsenate and what would be the consequences for As transfer from soil to plant. The compartment system approach with Zea mays as model crop was chosen as an experimental setup. The system is equipped with micro suction cups and allowed us to investigate processes occurring in the vicinity of roots. As a case study, an artificial quartz substrate with well defined soil physical properties was fertilized, spiked with As V, and amended with increasing amounts of goethite (0, 1, and 4 g kg(-1) in treatments G-0, G-1, and G-4, respectively). The addition of goethite alleviated the As V-induced growth reduction and reduced As V transfer from the substrate to the plant but induced P deficiency at the same time. When low amounts of goethite (1 g kg(-1)) were added, plants mobilized PV but not As V, which might be related to differences in surface complexation reported for PV and As V. No mobilization of PV or As V was observed with the addition of higher amounts of goethite, probably because of decreasing competition between organic anions, PV, and As V for binding sites. 相似文献
17.
Kienle C Köhler HR Filser J Gerhardt A 《Environmental pollution (Barking, Essex : 1987)》2008,152(3):612-620
We examined acute (2 h exposure of 5-day-old larvae) and subchronic (exposure from fertilization up to an age of 11 days) effects of NiCl(2).6H2O on embryos and larvae of zebrafish (Danio rerio), both alone and in combination with oxygen depletion. The following endpoints were recorded: acute exposure: locomotory activity and survival; subchronic exposure: hatching rate, deformations, locomotory activity (at 5, 8 and 11 days) and mortality. In acute exposures nickel chloride (7.5-15 mg Ni/L) caused decreasing locomotory activity. Oxygen depletion (or=10 mg Ni/L resulted in delayed hatching at an age of 96 h, in decreased locomotory activity at an age of 5 days, and increased mortality at an age of 11 days (LC20=9.5 mg Ni/L). The observed LOEC for locomotory activity (7.5 mg Ni/L) is in the range of environmentally relevant concentrations. Since locomotory activity was already affected by acute exposure, this parameter is recommended to supplement commonly recorded endpoints of toxicity. 相似文献
18.
Juliane Straube Jill Manteufel Janin Heinze Karsten Fehlhaber Uwe Truyen Thiemo Albert 《Food and environmental virology》2010,2(2):74-82
Since highly pathogenic avian influenza virus H5N1 emerged in 1997, avian influenza is considered one of the most important
infectious diseases globally. In respect of virus transmission to humans, the consumption of raw poultry products remains
of serious concern. In this study, data about survival time and inactivation kinetics of two low pathogenic avian influenza
virus (AIV) strains (H3N8, H5N6) in short fermented raw sausage were obtained. In addition, the impact of the preserving factors
d,l-lactic acid and sodium chloride on virus infectivity was evaluated through in vitro studies. Virus infectivity was confirmed
in embryonated chicken eggs. Inactivation of H3N8 was seen in d,l-lactic acid solutions (0.15 and 0.20%, pH 4.40–4.70 and pH 3.80–3.91) at both temperatures (20 vs. 4°C) during 3 days of
exposure. However, infectious virus particles could still be detected after exposure to 0.1% d,l-lactic acid (pH 5.80–5.99). In all NaCl solutions (2, 6 and 12% w/v), infectivity of the H3N8 strain decreased steadily but
reduction of the virus titre increased significantly with higher temperature. In raw sausages, decline in virus titre was
observed for both strains during ripening and storage. Thereby, decline of virus infectivity was dependent on time and temperature
with a more marked effect at higher temperatures (22 vs. 7°C). At refrigeration (7°C), both viruses maintained infectivity
over 14 days. Results indicate that appropriate processing of short fermented raw poultry sausage is likely to reduce risk
of virus exposure due to adequate inactivation of AIV during ripening and storage. 相似文献
19.
Detection of methylquinoline transformation products in microcosm experiments and in tar oil contaminated groundwater using LC-NMR 总被引:1,自引:0,他引:1
N-heterocyclic compounds are known pollutants at tar oil contaminated sites. Here we report the degradation of methyl-, and hydroxy-methyl-substituted quinolines under nitrate-, sulfate- and iron-reducing conditions in microcosms with aquifer material of a former coke manufacturing site. Comparison of degradation potential and rate under different redox conditions revealed highest degradation activities under sulfate-reducing conditions, the prevailing conditions in the field. Metabolites of methylquinolines, with the exception of 2-methylquinolines, were formed in high amounts in the microcosms and could be identified by 1H NMR spectroscopy as 2(1H)-quinolinone analogues. 4-Methyl-, 6-methyl-, and 7-methyl-3,4-dihydro-2(1H)-quinolinone, the hydrogenated metabolites in the degradation of quinoline compounds, were identified by high resolution LC-MS. Metabolites of methylquinolines showed persistence, although for the first time a transformation of 4-methylquinoline and its metabolite 4-methyl-2(1H)-quinolinone is described. The relevance of the identified metabolites is supported by the detection of a broad spectrum of them in groundwater of the field site using LC-NMR technique. LC-NMR allowed the differentiation of isomers and identification without reference compounds. A variety of methylated 2(1H)-quinolinones, as well as methyl-3,4-dihydro-2(1H)-quinolinone isomers were not identified before in groundwater. 相似文献
20.
Juliane B. Brown William A. Battaglin Robert E. Zuellig 《Journal of the American Water Resources Association》2009,45(1):68-82
Abstract: Recent national concerns regarding the environmental occurrence of emerging contaminants (ECs) have catalyzed a series of recent studies. Many ECs are released into the environment through discharges from wastewater treatment plants (WWTPs) and other sources. In 2005, the U.S. Geological Survey and the City of Longmont initiated an investigation of selected ECs in a 13.8‐km reach of St. Vrain Creek, Colorado. Seven sites were sampled for ECs following a Lagrangian design; sites were located upstream, downstream, and in the outfall of the Longmont WWTP, and at the mouths of two tributaries, Left Hand Creek and Boulder Creek (which is influenced by multiple WWTP outfalls). Samples for 61 ECs in 16 chemical use categories were analyzed and 36 were detected in one or more samples. Of these, 16 have known or suspected endocrine‐disrupting potential. At and downstream from the WWTP outfall, detergent metabolites, fire retardants, and steroids were detected at the highest concentrations, which commonly exceeded 1 μg/l in 2005 and 2 μg/l in 2006. Most individual ECs were measured at concentrations less than 2 μg/l. The results indicate that outfalls from WWTPs are the largest but may not be the sole source of ECs in St. Vrain Creek. In 2005, high discharge was associated with fewer EC detections, lower total EC concentrations, and smaller EC loads in St. Vrain Creek and its tributaries as compared with 2006. EC behavior differed by individual compound, and some differences between sites could be attributed to analytical variability or to other factors such as physical or chemical characteristics or distance from contributing sources. Loads of some ECs, such as diethoxynonylphenol, accumulated or attenuated depending on location, discharge, and distance downstream from the WWTP, whereas others, such as bisphenol A, were largely conservative. The extent to which ECs in St. Vrain Creek affect native fish species and macroinvertebrate communities is unknown, but recent studies have shown that fish respond to very low concentrations of ECs, and further study on the fate and transport of these contaminants in the aquatic environment is warranted. 相似文献