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411.
The effects of adding biosolids to a green waste feedstock (100% green waste, 25% v/v biosolids or 50% biosolids) on the properties of composted products were investigated. Following initial composting, 20% soil or 20% fly ash/river sand mix was added to the composts as would be carried out commercially to produce manufactured soil. Temperatures during composting reached 50 °C, or above, for 23 days when biosolids were included as a composting feedstock but temperatures barely reached 40 °C when green waste alone was composted. Addition of biosolids to the feedstock increased total N, EC, extractable NH4, NO3 and P but lowered pH, macroporosity, water holding capacity, microbial biomass C and basal respiration in composts. Additions of soil or ash/sand to the composts greatly increased the available water holding capacity of the materials. Principal component analysis (PCA) of PCR-DGGE 16S rDNA amplicons separated bacterial communities according to addition of soil to the compost. For fungal ITS-RNA amplicons, PCA separated communities based on the addition of biosolids. Bacterial species richness and Shannon’s diversity index were greatest for composts where soil had been added but for fungal communities these parameters were greatest in the treatments where 50% biosolids had been included. These results were interpreted in relation to soil having an inoculation effect and biosolids having an acidifying effect thereby favouring a fungal community. 相似文献
412.
A. Gauthier P. Le Coustumer M. Motelica O. F. X. Donard 《Waste management (New York, N.Y.)》2000,20(8)
The development of predictive models for the long term evolution of nuclear waste glass requires the complete knowledge of the glass dissolution at the laboratory scale. A new approach was developed to determine the initial reaction during the first steps of experience, a new concept was developed, based on the combination of dynamic leaching test and the characterization of the altered materials. With this experimental set-up it is possible to follow in real time the glass alteration process at a fine temporal scale. The results put in evidence a singular behaviour of the lanthanide, shown by a concentration peak of La, Nd and Ce after 2 h and a quick decrease of their concentration measured on line in the solution during the leaching test. This fact is directly linked to the development of an interphase (altered layer which differs from the initial solid by its texture, structure and chemical composition) at the interface of the glass surface and the leaching solution. This work is an attempt to integrate the formation of the alteration products (here the interphase) during leaching into the dissolution mechanisms of a nuclear waste glass. A model is proposed and discussed. 相似文献
413.
Marcelo de O. Milfont Epifania Emanuela M. Rocha Afonso Odério N. Lima Breno M. Freitas 《Environmental Chemistry Letters》2013,11(4):335-341
This is the first report showing that using honeybee (Apis mellifera) and wild pollinators complementary pollination can enhance soybean productivity (Glycine max). Current industrial production of soybean involves autopollination and high loads of pesticides. Therefore, growers have neglected possible biotic pollination despite suggestions that soybean benefit from insect pollinators. Reports advocating possible biotic pollination are based on experiments where bees are caged with flowering plants and the absence of pesticides, thus not in field conditions. Therefore, here we compared in field conditions soybean yield produced (1) independently of biotic pollinators, (2) with wild pollinators and (3) with honeybee colonies. Results showed an increase of +6.34 % of soybean yield in areas where wild pollinators had free access to flowers. The introduction of honeybee colonies further raised the yield of +18.09 %. Our findings therefore show that, though soybean is autogamous, allowing pollination by wild pollinators leads to higher yields. Moreover, adding honeybee mitigates pollination deficits and improves yield compared to current practices. 相似文献
414.
Kelly O. Maloney Donald E. Weller Daniel E. Michaelson Patrick J. Ciccotto 《Environmental Modeling and Assessment》2013,18(1):1-12
Species distribution models (SDMs) are often used in conservation planning, but their utility can be improved by assessing the relationships between environmental and species response variables. We constructed SDMs for 30 stream fishes of Maryland, USA, using watershed attributes as environmental variables and presence/absence as species responses. SDMs showed substantial agreement between observed and predicted values for 17 species. Most important variables were natural attributes (e.g., ecoregion, watershed area, latitude/longitude); land cover (e.g., %impervious, %row crop) was important for three species. Focused analyses on four representative species (central stoneroller, creek chub, largemouth bass, and white sucker) showed the probability of presence of each species increased non-linearly with watershed area. For these species, SDMs built to predict absent, low, and high densities were similar to presence/absence predictions but provided probable locations of high densities (e.g., probability of high-density creek chub decreased rapidly with watershed area). We applied SDMs to predict suitability of watersheds within the study area for each species. Maps of suitability and the environmental and species response relationships can help develop better management plans. 相似文献
415.
O. A. Bergstad 《Marine Biology》1990,107(1):25-39
The roundnose grenadierCoryphaenoides rupestris Gunnerus, 1765 occurs benthopelagically in the deepest parts of the Norwegian Deep, i.e., at depths >300 m in the Skagerrak. Based on studies of distribution carried out in the years 1984 to 1987, it appears that the concentrations contitute a largely self-sustaining population. From age-readings using transverse otolith sections, the population appears to consist of at least 50 to 60 age-groups and to include a very high proportion of old fish. Population growth-curves in terms of length and weight revealed that females grow comparatively fast for a longer time and attain greater asymptotic sizes than males. Maximum lengths appear however to be lower in the Skagerrak than in waters to the west of Scotland, and the length/weight data indicate that the weight at a given length (weight at length) of large individuals is less than reported from other areas. The major spawning season is in late autumn, probably extending into early winter. Fifty per-cent of females and males become mature for the first time at Age 10 and 8 yr, respectively. Corresponding pre-anal lengths are 11 and 8.5 cm. 相似文献
416.
O. Milošević-Djordjević D. Grujićić S. Arsenijević D. Marinković 《Russian Journal of Ecology》2004,35(6):426-430
Kragujevac, as an important industrial and economic center of the region, is now placed on the top of the list of environmentally endangered cities in our country. The aim of this biomonitoring study was to evaluate cytogenetic damage in a sample of newborns from Kragujevac after contamination of the environment entailed by the intensive bombing of the industrial zone of this city in the spring of 1999. The frequency of micronuclei (MN) in peripheral blood lymphocytes in a total of 61 phenotypically healthy newborns was analyzed before and after the NATO bombing. Analysis of micronuclei has been performed using the cytokinesis-block technique (CB MN test). Average MN frequency in lymphocytes of newborns before the bombing (N = 25) was 5.77 ± 0.85/1000 analyzed cells. After the bombing (N = 36), the average frequency of MN increased by a factor of 1.4 (8.11 ± 0.85), compared to the control frequency before the bombing. Statistical difference (p < 0.05) was established by Student's t-test. Our data suggest that such changes in genetic material were a direct consequence of contamination of the living environment. 相似文献
417.
418.
419.
The potential of commonly available green alga Ulva lactuca was investigated as viable biomaterials for removal of synthetic azo dye (Direct Yellow 12, DY-12) from aqueous solution. The results obtained from the batch experiments revealed that the ability of the U. lactuca to remove DY-12 from its aqueous solution was dependent on the dye concentration, pH, and algal biomass but less dependent on the particle size of the U. lactuca. The equilibrium conditions and kinetics of adsorption were investigated, and the adsorption kinetic was consistent with the pseudo-second-order model (R2=1). The adsorption isotherm followed only the Freundlich model with a correlation coefficient R2=0.99. This study demonstrated that the U. lactuca could be used as an effective biosorbent for the removal of DY-12 from its aqueous solution. 相似文献
420.