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1.

Background  

The Atacama Desert in Northern Chile is one of the most arid places on earth. However, fog occurs regularly at the coastal mountain range and can be collected at different sites in Chile to supply settlements at the coast with freshwater. This is also planned in the fog oasis Alto Patache (20°49′S, 70°09′W). For this pilot study, we collected fog water samples in July and August 2008 for chemical analysis to find indications for its suitability for domestic use.  相似文献   

2.

Background  

In the present study, we report the analytical results of pp′DDT, pp′DDE and pp′DDD determination in lake water, plankton and zooplanktivorous fish of Lake Maggiore (Northern Italy), rather recently polluted by DDT of industrial origin, in order to understand the bottom-up pollution transfer among the abiotic and biotic components of the lake ecosystem.  相似文献   

3.

Introduction  

We report on the analysis of 4,4′-dichlorodiphenyltrichloroethane (4,4′-DDT) and its metabolites in thatch and branch samples constituting the wall materials of dwellings from South African subtropical areas. This approach was used to assess the exposure to DDT in the residents of the dwellings after indoor residual spraying (IRS) following recommended sanitation practices against malaria vectors.  相似文献   

4.

Background, aim, and scope  

Passive air sampling survey of the Central and Eastern Europe was initiated in 2006. This paper presents data on toxic organic compounds such as polychlorinated biphenyls (PCB 28, 52, 101, 118, 153, 138, and 180), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), hexachlorocyclohexane compounds (α-HCH, β-HCH,γ-HCH, δ-HCH), and dichloro-diphenyl-trichloroethane (DDT) compounds (p,p′DDE, p,p′DDD, p,p′DDT, o,p′DDE, o,p′DDD, and o,p′DDT) determined in ambient air and soil samples collected at Estonian monitoring stations.  相似文献   

5.

Purpose  

Dechlorination of polychlorinated biphenyls (PCBs) by nanoscale zerovalent iron (NZVI) is often strongly hindered by increased pH because large amounts of H+ ions were consumed during the surface reaction. The main objective of this work was to evaluate the effect of pH control in acid on the dechlorination processes of PCBs and to compare the dechlorination efficiency between 2,4,4′-trichlorobiphenyl (2,4,4′-CB) and the extracted PCBs from the field PCBs-contaminated soil in this system.  相似文献   

6.
In this study an attempt is made to estimate nitrogen and phosphorus discharged to the environment from the striped catfish (Pangasianodon hypophthalmus) farming sector in the Mekong Delta (8°33′–10°55′N, 104°30′–106°50′E), South Vietnam. The sector accounted for 687,000 t production in 2007 and 1,094,879 t in 2008, with over 95% of the produce destined for export to over 100 countries. Commercial and farm-made feeds are used in catfish farming, currently the former being more predominant. Nitrogen discharge levels were similar for commercial feeds (median 46.0 kg/t fish) and farm-made feeds (median 46.8 kg/t fish); whilst, phosphorus discharge levels for commercial feeds (median 14.4 kg/t fish) were considerably lower than for farm-made feeds (median 18.4 kg/t fish). Based on the median nutrient discharge levels for commercial feeds, striped catfish production in the Mekong Delta discharged 31,602 t N and 9,893 t P, and 50,364 t N and 15,766 t P in 2007 and 2008, respectively. However, the amount of nutrients returned directly to the Mekong River may be substantially less than this as a significant proportion of the water used for catfish farming as well as the sludge is diverted to other agricultural farming systems. Striped catfish farming in the Mekong Delta compared favourably with other cultured species, irrespective of the type of feed used, when the total amounts of N and P discharged in the production of a tonne of production was estimated.  相似文献   

7.

Introduction  

Acid orange 52 (AO52), extensively used in textile industries, was decolorized by Pseudomonas putida mt-2. AO52 azoreduction products such as N,N′-dimethyl-p-phenylenediamine (DMPD) and 4-aminobenzenesulfonic acid (4-ABS), were identified in the static degradation mixture. These amines were identified only in media of static incubation, which is consistent with their biotransformation under shaken incubation (aerobic conditions).  相似文献   

8.
Background, aim, and scope  Foraging patches can be described as a nested hierarchy of aggregated resources, implying that study of foraging by wild animals should be directed across different spatial scales. However, almost all previous research on habitat selection by the giant panda has concentrated upon one scale. In this research, we carried out a field study to understand foraging patch selection by giant pandas in winter at both microhabitat and feeding site scales and, for the first time, attempted to understand how long it would stay at the feeding sites before moving on. Materials and methods  The field survey was conducted from November 2002 to March 2003 at Fengtongzhai Nature Reserve (102°48′–103°00′ E, 30°19′–30°47′ N), Baoxing County of Sichuan Province, China, to collect data in both microhabitat and control plots. The microhabitat plots were located by fresh feces or foraging traces left by giant pandas, and the control plots were established to reflect the environment. Within each microhabitat plot, one 1 × 1 m2 plot was centralized at the center of each feeding site, in which numbers of old bamboos and old shoots, including eaten and uneaten, were counted, respectively. Results  The results showed that winter microhabitats selected by this species were characteristic of gentle slopes and high old-shoot proportions and that the latter was even higher at feeding sites. Two selection processes, namely, from the environment to microhabitats and from the latter to feeding sites, were found during this species’ foraging patch utilization. Giant pandas preferred to eat old shoots to old bamboo at feeding sites in winter and did not leave unless old-shoot density fell to lower than the average in the environment. Discussion  Both microhabitats and feeding sites selected by giant pandas were characteristic of high old-shoot density, indicating that the preferred food item had a significant influence upon its foraging patch selection. The preference for gentle slopes by giant pandas was presumed to save energy in movement or reflect the need to sit and free its fore-limbs to grasp bamboo culms when feeding but also seemed to be correlated with an easier access to old shoots. The utilization of old shoots at feeding sites was assumed to help maximize energy or nutrient intake during their foraging. Conclusions  The difference between microhabitat plots and control plots and between microhabitats and feeding sites uncovered a continuous selection process from the environment via microhabitats to feeding sites. The utilization of old shoots at feeding sites was parallel to the marginal value theorem. The selection and abandonment of foraging patches by giant pandas was an optimal behavioral strategy adapted to their peculiar food with high cellulose and low protein. Recommendations and perspectives  Our results uncovered the importance of multiple scales in habitat selection research. To further understand the process of habitat selection, future research should pay more attention to resolve the question of how to locate foraging patches under dense bamboo forests by the giant panda, which was traditionally considered to have poor eyesight, although our research has answered what type of habitats the giant panda prefers and when to leave.  相似文献   

9.
Background, Aims and Scope Fish-eating seabirds are recognized to be at risk of accumulating toxic contaminants due to their high position in the trophic web and to their low ability to metabolize xenobiotic compounds. Penguins are widely distributed in Antarctica and represent an important fraction of the Antarctic biomass. They feed mainly on krill and, depending on krill availability, also on fish. It has been reported that predators may be a sink for volatile and toxic chemicals and this may pose a serious environmental problem. Polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-dioxins (PCDDs),-furans (PCDFs), and-biphenyls (PCBs), including non-ortho congeners, hexachlorobenzene (HCB) and p,p′-DDE, were quantified in three species of Antarctic Pygoscelids in order to evaluate their accumulation patterns. The potential toxicity of twenty-two dioxin-like congeners was assessed and expressed as 2,3,7,8-tetraCDD equivalents (TEQs). Differences between males and females were investigated. Methods Blood samples of the Adélie penguin Pygoscelis adeliae, Chinstrap penguin Pygoscelis antarctica and Gentoo penguin Pygoscelis papua were collected at Admiralty Bay, King George Is (62°10′39″ S, 58°26′46″ W) in February 2004. Halogenated hydrocarbons were identified and quantified using gas chromatography coupled with gas chromatography mass spectrometry analyses. Results are expressed on a wet weight basis. Results and Discussion HCB, p,p′-DDE and ΣPCBs were higher in Adélie penguins (6.7±6.1, 8.2±3.3 and 9.8±3.8 ng/g, respectively) than in Chinstrap and Gentoo penguins, both of which showed values in the same order of magnitude, but approximately 40% lower than Adélie penguins. Hexa-CBs ranged 35–45% of the residue. Low-chlorinated PCBs (nos. 70+76+95+56+60+101) accounted for 40–60% in the three species. PCB101 made up 15% of the residue in Adélie penguins. PBDEs were 291±477, 107±104 and 116±108 pg/g in Adélie, Chinstrap and Gentoo penguins, respectively; the most abundant congeners were BDE47 in Adélie and Chinstrap penguins and BDE17 in Gentoo penguins. PCDDs were 22±32, 6.5±7.4 and 18±23 pg/g in Adélie, Chinstrap and Gentoo penguins, respectively. PCDFs were higher in Adélie penguins and lower in Chinstrap penguins. PCDDs/Fs and PBDEs were higher in males than in females of Gentoo and Chinstrap penguins; differences in concentrations were likely related to the partial detoxification that occurs in females during egg formation. Of the four non-ortho PCBs measured, PCB126 occurred at the highest concentrations and contributed the majority of the non-ortho PCB-TEQ in Gentoo and Chinstrap penguins. The highest TEQs were found in the Gentoo penguin and due mainly to PCDDs and non-ortho PCBs. Conclusions POP concentrations in penguins were lower than those found in seabird species from other areas of the world. Different chemical accumulation patterns were observed in relation to species and sex; the Adélie penguin showed the highest POP levels. Dissimilar ecological or metabolic features may be involved; the diverse timing of reproduction steps can be responsible for those differences; moreover, Adélie penguins feed on krill (a fatty resource) more abundantly than the other two species during the rearing period. Recommendation and Outlook The South Shetland Islands might be subjected to a higher chemical impact with respect to the rest of Antarctica, due to their being near South America. Because penguins are fish-eating birds showing low detoxifying capacities and key-species in Antarctic ecosystems, further studies on their xenobiotic metabolism should be carried out.  相似文献   

10.
Global warming has become a source of awareness regarding the potential deleterious effects of extreme abiotic factors (e.g., temperature, dissolved oxygen (DO) levels) and also their influence on chemicals toxicity. In this work, we studied the combined effects of nickel and temperature (low and high levels) and nickel and low levels of DO to Daphnia magna, and concentration addition and independent action concepts as well as their deviations for synergism/antagonism, dose ratio and dose level dependency, were applied to survival and feeding rate data. Nickel single exposure showed an LC50 value for 48 h of 7.36 mg l−1 and an EC50 value for feeding impairment at 2.41 mg l−1. In the acute exposures to high and low temperatures, 50% of mortality was observed, respectively, at 30.7°C and 4.2°C whereas 50% reduction on the feeding activity was recorded at 22.6°C and 16.0°C. Relatively to low DO levels, a LC50 value for 48 h of 0.5 mg l−1 was obtained; feeding activity EC50 value was 2 mg l−1. On acute combined experiments, antagonism was observed for the combination of nickel and extreme temperatures, whereas a synergistic behaviour was observed in the combined exposure of nickel and low DO levels. At sublethal levels, nickel showed to be the main inducer of toxicity at high and low temperatures but not at low levels of dissolved oxygen. Toxicokinetics and toxicodynamics modelling studies should be made in the future to understand the toxicological pathways involved on complex combinations of stressors and to validate any conclusions.  相似文献   

11.

Purpose  

Gamma ray irradiation is considered as an effective way to degrade diclofenac. However, due to the extensive coexisting substances in natural waters, the use of gamma ray irradiation for degradation is often influenced by multiple factors. The various factors that affect degradation efficiency, such as initial diclofenac concentration, initial pH, and the concentration of the additives including H2O2 (·OH radical promoter), CH3OH (·OH radical scavenger), thiourea (·OH, H·, and eaq scavenger), humic acid, and NO3 (coexisting substances in natural waters), are investigated. Furthermore, possible intermediate products are identified and corresponding transformation pathways are proposed.  相似文献   

12.

Introduction  

This paper deals with the removal of two natural estrogens, estrone (E1) and 17β-estradiol (E2) and a synthetic one 17α ethinylestradiol (EE2) from wastewater in a laboratory-scale membrane bioreactor (MBR).  相似文献   

13.
Narozhniy Y  Zemtsov V 《Ambio》2011,40(6):575-588
Results of research into climate and glacier dynamics in the Altai Mountains (Russia) over the period of instrumental observations (1952–2008) are presented in this article. About 1030 glaciers with a total area of 805 km2 and volume of 42.5 km3 have been recorded in the Altai Region. The average summer air temperature in different regions of the Altai has increased during the study period from about 0.2°C (Aktru) to 1.1°C (Akkem). The annual atmospheric precipitation rate has also increased, by 8–10%. Since 1952, the glacier area in different regions of the Altai has decreased by 9–27%, and volume by 12–24%. By 2008, as a result of degradation, the total number of glaciers was 953 with an area of 724 km2 and volume of 38 km3.  相似文献   

14.

Purpose  

This study aims to examine whether addition of immobilising agents to a sandy, alkaline (pH = 8.1) soil, which had been contaminated with Pb and Zn by airborne particles from a Pb/Zn smelter, would substantially reduce metal bioavailability.  相似文献   

15.

Background, aim and scope  

The applicability of the Whole Effluent Assessment concept for the proof of compliance with the “best available techniques” has been analysed with paper mill wastewater from Germany by considering its persistency (P), potentially bio-accumulative substances (B) and toxicity (T).  相似文献   

16.

Background  

Cuttings and seedlings of Jatropha curcas L. were exposed to different regimes of lead (Pb) stress as Pb(NO3)2 at 0 (CK), 0.5, 1, 2, 3, and 4 mM kg−1 soil.  相似文献   

17.

Introduction  

We conducted a yearly polluted-reference sampling to assess the effects of petroleum pollution on life cycle characteristics of the meiobenthic nematode Odontophora villoti. Samples were taken every 15 days between 26 November 2004 and 25 November 2005 from two beaches of Bizerte bay (Tunisia), Rimel and Tunisian Refining Industries Company (TRIC). The latter site is located in front of the “Tunisian Refining Industries Company” runoff.  相似文献   

18.

Background, aim, and scope  

Unsaturated esters are emitted to the atmosphere from biogenic and anthropogenic sources, including those from the polymer industry. Little information exists concerning the atmospheric degradation of unsaturated esters, which are mainly initiated by OH radicals. Limited information is available on the degradation of alkenes by Cl atoms and almost no data exists for the reactions of unsaturated esters with Cl atoms. This data is necessary to assess the impact of such reactions in maritime environments where, under circumstances, OH radical- and Cl atom-initiated oxidation of the compounds can be important. Rate coefficients for the reactions of chlorine atoms with vinyl acetate, allyl acetate, and n-butyl acrylate have been determined at 298 ± 3 K and atmospheric pressure. The kinetic data have been used in combination with that for structurally similar compounds to infer the kinetic contributions from the possible reaction channels to the overall reaction rate.  相似文献   

19.

Purpose  

Samples from the German Environmental Specimen Bank (ESB) covering particularly the years 1994–1996, 2000–2002, and 2006–2009 were analyzed for perfluorinated compounds (PFC; mainly C4–C13 carboxylic and sulfonic acids) to gain an overview on current PFC levels and patterns in marine, limnetic, and terrestrial biota; to assess their concentrations in different trophic levels; and to investigate whether risk management measures for PFC are successful.  相似文献   

20.

Background, aim, and scope  

Methacrylates are α, β-unsaturated esters that are widely used in the polymer plastics and resins production. Kinetic information of NO3 radical reactions is especially scarce and a good understanding of all the atmospheric oxidation processes of these compounds is necessary in order to determine lifetimes in the atmosphere and to evaluate the impact of these reactions on the formation of ozone and other photooxidants.  相似文献   

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