The aim of this study was to obtain information on the presence and levels of hazardous organic pollutants in groundwater located close to solid waste landfills. Eighty-two environmental contaminants, including 16 polycyclic aromatic hydrocarbons (PAHs), 20 volatile organic compounds (VOCs), 29 polychlorinated biphenyls (PCBs), 7 dioxins (polychlorinated dibenzo-p-dioxins, PCDDs) and 10 furans (polychlorinated dibenzofurans, PCDFs) were monitored in areas characterised by different geological environments surrounding three municipal solid waste landfills (Palermo, Siculiana and Ragusa) in Sicily (Italy) in three sampling campaigns. The total concentrations of the 16 PAHs were always below the legal threshold. Overall, the Fl/Fl + Py diagnostic ratio revealed that PAHs had a petrogenic origin. VOC levels, except for two notable exceptions near Palermo landfill, were always below the legal limit. As concerns PCB levels, several samples were found positive with levels exceeding the legal limits. It is worth noting that the % PCB distribution differs from that of commercial compositions. In parallel, some samples of groundwater containing PCDDs and PCDFs exceeding the legal threshold were also found. Among the 17 congeners monitored, the most abundant were the highest molecular weight ones.
Environmental Science and Pollution Research - The aim of this study is to assess—for the first time—the concentration of the 16 polycyclic aromatic hydrocarbons (PAHs) in the muscle... 相似文献
Artisanal fishery activities support the livelihoods of millions of people worldwide, particularly in developing countries. Within these fisheries, distal global drivers can promote switching between alternative target resources. These drivers can promote the rapid development of new, unregulated and previously unexploited fisheries that pose a threat to the sustainability of ecosystems. In this paper, we describe a new artisanal shore gathering activity that targets a previously unexploited resource: the sandhopper (Orchestoidea tuberculata). The activity is driven by aquarium trade demand for food. We used mixed methods to describe the activity, assessed basic socio-economic incentives, and estimated Catches per Unit Effort. Results show that the sandhopper plays an important role for the livelihoods of shore gatherers engaged in the activity. Gatherers have adapted and developed two main extraction methods with different degrees of investment and extraction rates. Furthermore, gatherers have developed local knowledge regarding the ecology and management of the resource. Results show that economic incentives can motivate a rapid expansion of this unregulated activity. Future research gaps and management options to address the development of this fishery are discussed in light of these findings. 相似文献
Assessing the sustainability of complex development processes requires multi-causal and integrated analyses. We develop a
system-based methodology, rooted in interdisciplinary discussion and consensus building between 15 experts, to construct a
multi-causal diagram which examines the sustainability of the Argentine Pampas′ process of agriculturization. The resulting
diagram includes 25 factors and provides a big-picture of the multiple dimensions and interrelations affecting sustainability.
According to this examination, the increasing concentration of production and the incorporation of technological innovations,
triggered by economic and institutional factors, are the cause of environmental distresses and social changes, whose consequences
for sustainability are still highly disputed. Nevertheless, the symptoms of both environmental and social unsustainability
are more evident in the case of the extra-Pampean regions than in the Pampas. This suggests that the Pampean agriculture model
should not be transferred to these regions without substantial modifications. The experts did not reach consensus on whether
the agriculturization process is overall sustainable or unsustainable. Lack of consensus revolved mainly around opposing perspectives
regarding the significance of the threats to environmental sustainability. The magnitude of socio-distributive unbalance and
loss of rural jobs were also contentious. Yet, the paper shows how the exercise of building a joint causal diagram was undoubtedly
helpful for linking piece-meal disciplinary facts, brought in from all fronts, into a comprehensive and coherent picture.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
Background, aim, and scope In this work, the potential for using olive-mill solid waste as an organic amendment for biochemical and biological restoration
of a trichloroethylene-contaminated soil, which has previously been stabilized through vermicomposting processes, has been
explored.
Materials and methods Trichloroethylene-contaminated water was pumped into soil columns with a layer of vermicompost at 10-cm depth (biobarrier
system). The impacts of the trichloroethylene on the microbial community were evaluated by determining: (1) the overall microbial
activity (estimated as dehydrogenase activity) and enzyme activities related to the main nutrient cycles (β-glucosidase, o-diphenoloxidase, phosphatase, urease, and arylsulphatase activities). In addition, isoelectric focusing of the soil extracellular
humic-β-glucosidase complexes was performed to study the enzymatically active humic matter related to the soil carbon cycle.
(2) The soil bacterial diversity and the molecular mechanisms for the bacterial resistance to organic solvents were also determined.
For this, polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) was used to detect changes in bacterial
community structure and PCR-single-strand conformational polymorphism (SSCP) was developed and optimised for detection and
discrimination of the resistance-nodulation-division (RND) genes amplified from the contaminated soils.
Results Vermicompost reduced, with respect to the unamended soil, about 30% of the trichloroethylene leaching during the first month
of the experiment. Trichloroethylene had a marked negative effect on soil dehydrogenase, β-glucosidase, urease, phosphatase,
and arylsulphatase activities. Nevertheless, the vermicompost tended to avoid this toxic effect. Vermicompost also displays
stable humic-β-glucosidase complexes that increased the extracellular activity related to C-cycle in the contaminated soils.
The isoelectric focusing technique showed a more biochemically active humic matter in the soil sampled under the vermicompost.
The behaviour of the three main phyla of bacteria isolated from the DGGE bands was quite different. Bands corresponding to
Actinobacteria disappeared, whereas those affiliated with Proteobacteria remained after the trichloroethylene contamination. The disappeared Actinobacteria became visible in the soil amended with the vermicompost. Bands corresponding to Bacteriodetes appeared only in columns of contaminated soils. In this study, six types of RND proteins were detected by PCR-SSCP in the
natural soil, three in the trichloroethylene-contaminated soil and 7/5 in trichloroethylene-contaminated soil above/below
the vermicompost in the biobarrier columns. Trichloroethylene tended to reduce or eliminate all the clones detected in the
uncontaminated soil, whereas new efflux pumps appeared in the biobarrier columns.
Discussion Although enzymes incorporated into the humic substances of vermicomposted olive wastes are quite stable, trichloroethylene
also inhibited the background levels of the soil extracellular β-glucosidase activity in the amended soils. The decrease was
less severe in the biobarrier system, but in any case, no relation was found between the levels of trichloroethylene in soil
and extracellular β-glucosidase activity, or between the latter and the quantity of humic carbon in soils. The isoelectric
focusing technique was carried out in the humic fraction to determine whether the loss of activity occurred in overall extracellular
β-glucosidase or in that linked to stable humic substances (humic–enzyme complexes). The contaminated soils showed the lower
enzyme activities, whereas contaminated and amended soils presented greater quantity of focalised (and therefore stable) humic
carbon and spectra heterogeneity: very different bands with higher enzyme activities. No clear relationship between trichloroethylene
concentration in soil and diversity of the bacterial population was noted. Similar patterns could be found when the community
structures of bacteria and microbial activity were considered. Since the use of the dehydrogenase assay has been recognised
as a useful indicator of the overall measure of the intensity of microbial metabolism, these results could be attributed to
PCR-DGGE methodology, since the method reveals the presence of dominant populations regardless of their metabolic state. Trichloroethylene
maintained or even increased the number of clones with the DNA encoding for RND proteins, except for the contaminated soil
located above the vermicompost. However, the main effect of trichloroethylene was to modify the structure of the community
in contaminated soils, considering the type of efflux pumps encoded by the DNA extracted from soil bacteria.
Conclusions Trichloroethylene inhibited specific functions in soil and had a clear influence on the structure of the autochthonous bacterial
community. The organic matter released by the vermicomposted olive waste tended to avoid the toxic effect of the contaminant.
Trichloroethylene also inhibited the background levels of the soil extracellular β-glucosidase activity, even when vermicompost
was present. In this case, the effect of the vermicompost was to provide and/or to stimulate the humic-β-glucosidase complexes
located in the soil humic fraction >104, increasing the resistance of the enzyme to the inhibition. The bacterial community from the soil presented significantly
different mechanisms to resistance to solvents (RND proteins) under trichloroethylene conditions. The effect of the vermicompost
was to induce these mechanisms in the autochthonous bacterial community and/or incorporated new bacterial species, able to
grow in a trichloroethylene-contaminated ambient. Coupled biochemical and molecular methodologies are therefore helpful approaches
in assessing the effect of an organic amendment on the biochemical and biological restoration of a trichloroethylene-contaminated
soil.
Recommendations and perspectives Since the main biochemical and biological effects of the organic amendment on the contaminated soil seem to be the incorporation
of biochemically active humic matter, as well as new bacterial species able to grow in a trichloroethylene-contaminated ambient,
isoelectric focusing and PCR-SSCP methodologies should be considered as parts of an integrated approach to determine the success
of a restoration scheme. 相似文献
Cumulative human impacts across the world's oceans are considerable. We therefore examined a single model taxonomic group, the penguins (Spheniscidae), to explore how marine species and communities might be at risk of decline or extinction in the southern hemisphere. We sought to determine the most important threats to penguins and to suggest means to mitigate these threats. Our review has relevance to other taxonomic groups in the southern hemisphere and in northern latitudes, where human impacts are greater. Our review was based on an expert assessment and literature review of all 18 penguin species; 49 scientists contributed to the process. For each penguin species, we considered their range and distribution, population trends, and main anthropogenic threats over the past approximately 250 years. These threats were harvesting adults for oil, skin, and feathers and as bait for crab and rock lobster fisheries; harvesting of eggs; terrestrial habitat degradation; marine pollution; fisheries bycatch and resource competition; environmental variability and climate change; and toxic algal poisoning and disease. Habitat loss, pollution, and fishing, all factors humans can readily mitigate, remain the primary threats for penguin species. Their future resilience to further climate change impacts will almost certainly depend on addressing current threats to existing habitat degradation on land and at sea. We suggest protection of breeding habitat, linked to the designation of appropriately scaled marine reserves, including in the High Seas, will be critical for the future conservation of penguins. However, large‐scale conservation zones are not always practical or politically feasible and other ecosystem‐based management methods that include spatial zoning, bycatch mitigation, and robust harvest control must be developed to maintain marine biodiversity and ensure that ecosystem functioning is maintained across a variety of scales. Contaminación, Pérdida de Hábitat, Pesca y Cambio Climático como Amenazas Críticas para los Pingüinos 相似文献
Cytogenetic data are presented for 11 473 chorionic villus sampling (CVS) procedures from nine centres in the U.S. NICHD collaborative study. A successful cytogenetic diagnosis was obtained in 99.7 per cent of cases, with data obtained from the direct method only (26 per cent), culture method only (42 per cent), or a combination of both (32 per cent). A total of 1.1 per cent of patients had a second CVS or amniocentesis procedure for reasons related to the cytogenetic diagnostic procedure, including laboratory failures (27 cases), maternal cell contamination (4 cases), or mosaic or ambiguous cytogenetic results (98 cases). There were no diagnostic errors involving trisomies for chromosomes 21, 18, and 13. For sex chromosome aneuploidies, one patient terminated her pregnancy on the basis of non-mosaic 47,XXX in the direct method prior to the availability of results from cultured cells. Subsequent analysis of the CVS cultures and fetal tissues showed only normal female cells. Other false-positive predictions involving non-mosaic aneuploidies (n = 13) were observed in the direct or culture method, but these cases involved rare aneuploidies: four cases of tetraploidy, two cases of trisomy 7, and one case each of trisomies 3, 8, 11, 15, 16,20, and 22. This indicates that rare aneuploidies observed in the direct or culture method should be subjected to follow-up by amniocentesis. Two cases of unbalanced structural abnormalities detected in the direct method were not confirmed in cultured CVS or amniotic fluid. In addition, one structural rearrangement was misinterpreted as unbalanced from the direct method, leading to pregnancy termination prior to results from cultured cells showing a balanced, inherited translocation. False-negative results (n = 8) were observed only in the direct method, including one non-mosaic fetal abnormality (trisomy 18) detected by the culture method and seven cases of fetal mosaicism (all detected by the culture method). Mosaicism was observed in 0.8 per cent of all cases, while pseudomosaicism (including single trisomic cells) was observed in 1.6 per cent of cases. Mosaicism was observed with equal frequency in the direct and culture methods, but was confirmed as fetal mosaicism more often in cases from the culture method (24 per cent) than in cases from the direct method (10 per cent). The overall rate of maternal cell contamination was 1.8 per cent for the culture method, but there was only one case of incorrect sex prediction due to complete maternal cell contamination which resulted in the birth of a normal male. The rate of maternal cell contamination was significantly higher in samples obtained by the transcervical sampling method (2. 16 per cent) than in samples obtained by the transabdominal method (0.79 per cent). From these data, it is clear that the culture method has a higher degree of diagnostic accuracy than the direct method, which should not be used as the sole diagnostic technique. The direct method can be a useful adjunct to the culture method, in which maternal cell contamination can lead to incorrect sex prediction and potentially to false-negative diagnostic results. 相似文献