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601.
602.
603.
Bernhardt ES Colman BP Hochella MF Cardinale BJ Nisbet RM Richardson CJ Yin L 《Journal of environmental quality》2010,39(6):1954-1965
Growing concerns over the potential for unintended, adverse consequences of engineered nanoparticles (ENPs) in the environment have generated new research initiatives focused on understanding the ecological effects of ENPs. Almost nothing is currently known about the fate and transport of ENPs in environmental waters, soils, and sediments or about the biological impacts of ENPs in natural environments, and the bulk of modern nanotoxicogical research is focused on highly controlled laboratory studies with single species in simple media. In this paper, we provide an ecological perspective on the current state of knowledge regarding the likely environmental impacts of nanomaterials and propose a strategy for making rapid progress in new research in ecological nanoscience. 相似文献
604.
605.
A laboratory-scale bioremediation unit was designed, built and tested for the bio-removal of several Direct textile dyes.
Four experiments were carried out to assess the efficiency of the bioremediation unit using Aspergillus niger fungal strain. Three commonly used Direct dyes and textile dyes mixture (simulated effluent: Direct brown, Direct violet,
Direct green) were tested in this study. The strain of A. niger was efficient in the removal of the three Direct dyes. The decolorization percentages of the dyes after 24 h of incubation
were 56.2, 51.7, and 95.4% for Direct brown, Direct green, Direct violet dyes, respectively. The percentages increased up
to 79.4, 86.4, and 96.7% after 72 h of incubation for the same dyes, respectively. The results also showed that the fungal
strain reduced the chemical oxygen demand values of simulated dye effluents from 165 to 564 mg/l with most of the dyes. The
assessment of bioremediation products on biomodel was conducted using a fresh water fish. The liver and brain of Nile tilapia
were tested to evaluate the expression of genes coding for several proteins related to stress such as metallothioneins (MTs),
cytochrome P450 (CYP450), and heat shock proteins (HSPs). To assess the alterations in the gene expression, ten animals from
each group were killed after 4 weeks of treatment. The results revealed significant increases in the brain and hepatic mRNA
levels of all stress protein genes MT, CYP450, Hsp70a, b, and Hsp47 in the fish groups treated with industrial Direct violet,
green, and brown dye water. Exposure of tilapia to bioremediation products after treatment with A. niger fungi reduced the over-expression of the stress protein genes in the brain and liver tissues. 相似文献
606.
This work was undertaken to analyze nutrient contents of vegetation in an alpine meadow—Tungnath, North-West Himalaya, India.
The study pertains to the uptake, transfer and release of four main macronutrients (organic carbon, total nitrogen, total
potassium and total phosphorus) in grazed (exposed to extensive grazing by cattles) and ungrazed (grazing completely prohibited)
communities. Mineral concentration was recorded higher for the ungrazed sites compared to the grazed sites, and maximum standing
state of nutrients was found in roots. Belowground compartment (roots) contributed maximum share of mineral elements to soil.
Litter nutrients release was low because of low microbial activity and continuous removal of phytomass. Observations reveal
that there was very little amount of nutrient release from phytomass and vegetation in alpine are very poor source of mineral
recycling. Low transfer rate of minerals from one compartment to other is adequate for greater amount of these minerals that
are translocated back into the storage organs. A small proportion get removed through rain splash or through the removal of
hay during grazing as relatively high release rates in ungrazed sites when compared to grazed sites was observed. This translocation
can be considered as an important adaptation in alpine plants for survival during adverse environmental conditions, against
all types of biotic pressures and also for regeneration in the forthcoming growing season. 相似文献
607.
Ruchi Badola Syed Ainul Hussain Bidyut Kumar Mishra Bidyarani Konthoujam Sneha Thapliyal Parag Madhukar Dhakate 《The Environmentalist》2010,30(4):320-329
This paper examines the economic value of selected ecosystem services of Corbett Tiger Reserve, India. The direct cost was
derived from secondary sources, and indirect and opportunity costs through socioeconomic surveys. For recreational value the
individual approach to travel cost method was used, and to assess carbon sequestration the replacement cost method was used.
The maintenance cost of the reserve was estimated as US $2,153,174.3 year−1. The indirect costs in terms of crop and livestock depredation by wild animals ranged from US $2,153,174.3 year−1. The indirect costs in terms of crop and livestock depredation by wild animals ranged from US 2,408 to US $37,958 village−1 over a period of 5 years. The dependence of local communities was for fuel wood (US $37,958 village−1 over a period of 5 years. The dependence of local communities was for fuel wood (US 7,346 day−1), fodder (US $5,290 day−1), small timber, and other nontimber forest products. The recreational value of the reserve was estimated as US $5,290 day−1), small timber, and other nontimber forest products. The recreational value of the reserve was estimated as US 167,619 year−1. With the cost per visitor being US $2.5, the consumers’ surplus was large, showing the willingness of visitors to pay for
wildlife recreation. The forests of the reserve mitigate carbon worth US $2.5, the consumers’ surplus was large, showing the willingness of visitors to pay for
wildlife recreation. The forests of the reserve mitigate carbon worth US 63.6 million, with an annual flow of US $65.0 ha−1 year−1. The other benefits of the reserve include US $65.0 ha−1 year−1. The other benefits of the reserve include US 41 million through generation of electricity since 1972. The analysis reveals
that, though the benefits outweigh costs, they need to be accrued to local communities so as to balance the distribution of
benefits and costs. 相似文献
608.
João Carrola Nádia Santos Maria J. Rocha António Fontainhas-Fernandes Miguel A. Pardal Rogério A. F. Monteiro Eduardo Rocha 《Environmental science and pollution research international》2014,21(9):6057-6068
Fish are bioindicators of water pollution, and an increased rate of their erythrocyte nuclear morphological abnormalities (ENMAs)—and particularly of erythrocyte micronuclei (EMN)—is used as a genotoxicity biomarker. Despite the potential value of ENMAs and MN, there is scarce information about fish captured in Iberian estuaries. This is the case of the Portuguese estuaries of the Mondego, Douro and Ave, suffering from different levels of environmental stress and where chemical surveys have been disclosing significant amounts of certain pollutants. So, the aim of this study was to evaluate genotoxicants impacts and infer about the exposure at those ecosystems, using the grey mullet (Mugil cephalus) as bioindicator and considering the type and frequency of nuclear abnormalities of erythrocytes as proxies of genotoxicity. Sampling of mullets was done throughout the year in the important Mondego, Douro and Ave River estuaries (centre and north-western Portugal). The fish (total n?=?242) were caught in campaigns made in spring–summer and autumn–winter, using nets or fishing rods. The sampled mullets were comparable between locations in terms of the basic biometric parameters. Blood smears were stained with Diff-Quik to assess the frequencies of six types of ENMAs and MN (given per 1,000 erythrocytes). Some basic water physicochemical parameters were recorded to search for fluctuations matching the ENMAs. Overall, the most frequent nucleus abnormality was the polymorphic type, sequentially followed by the blebbed/lobed/notched, segmented, kidney shaped, vacuolated, MN and binucleated. The total average frequency of the ENMAs ranged from 73?‰ in the Mondego to 108?‰ in the Ave. The polymorphic type was typically ≥50 % of the total ENMAs, averaging about 51?‰, when considering all three estuaries. The most serious lesion—the MN—in fish from Mondego and Douro had a similar frequency (≈0.38?‰), which was significantly lower than that in the Ave (0.75?‰). No significant seasonal differences existed as to the MN rates and seasonal differences existed almost only in the Douro, with the higher values in AW. In general, the pattern of ENMAs frequencies was unrelated with the water physicochemical parameters. Considering the data for both the total ENMAs and for each specific abnormality, and bearing in mind that values of MN in fish erythrocytes >0.3?‰ usually reflect pollution by genotoxicants, it is suggested that mullets were likely being chronically exposed to such compounds, even in the allegedly less polluted ecosystem (Mondego). Moreover, data supported the following pollution exposure gradient: Mondego?<?Douro?<?Ave. The scenario and inferences nicely agree with the published data from chemical monitoring. 相似文献
609.
M. Crampon F. Bureau M. Akpa-Vinceslas J. Bodilis N. Machour F. Le Derf F. Portet-Koltalo 《Environmental science and pollution research international》2014,21(13):8133-8145
The natural biodegradation of seven polycyclic aromatic hydrocarbons (PAHs) by native microorganisms was studied in five soils from Normandy (France) from diffusely polluted areas, which can also pose a problem in terms of surfaces and amounts of contaminated soils. Bioavailability tests using cyclodextrin-based extractions were performed. The natural degradation of low molecular weight (LMW) PAHs was not strongly correlated to their bioavailability due to their sorption to geosorbents. Conversely, the very low degradation of high molecular weight (HMW) PAHs was partly correlated to their poor availability, due to their sorption on complexes of organic matter and kaolinites or smectites. A principal component analysis allowed us to distinguish between the respective degradation behaviors of LMW and HMW PAHs. LMW PAHs were degraded in less than 2–3 months and were strongly influenced by the relative percentage of phenanthrene-degrading bacteria over total bacteria in soils. HMW PAHs were not significantly degraded, not only because they were less bioavailable but also because of a lack of degrading microorganisms. Benzo[a]pyrene stood apart since it was partly degraded in acidic soils, probably because of a catabolic cooperation between bacteria and fungi. 相似文献
610.
Kerstin Holmgren 《Ambio》2014,43(1):19-29
Since the 1980s, Swedish lakes have in general become less acidified. Assessment of biological recovery is, however, hampered by poor pre-acidification data, confounding effects of climate change, and few lakes with annual sampling of fish and other organisms. Only three critically acidified, but non-limed, lakes had two decades of fish monitoring. The lakes had not yet recovered to pre-industrial chemical targets. Fish had low species richness compared to other organism groups. Roach (Rutilus rutilus) and/or European perch (Perca fluviatilis) were the dominant fish species, and the acid-sensitive roach had been lost from one of the lakes. Calcium decreased, possibly approaching pre-acidification concentrations, but exceeded minimum levels needed to sustain some Daphnia species. High or increasing levels of total organic carbon, likely due to reduced acidification and climate change, might influence the biological communities in unexpected ways, for example, facilitating more frequent occurrence of the invasive algae Gonyostomum semen. 相似文献