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371.
Metal binding properties of extracellular polymeric substances extracted from anaerobic granular sludges 总被引:1,自引:0,他引:1
Paul d’Abzac François Bordas Emmanuel Joussein Eric D. van Hullebusch Piet N. L Lens Gilles Guibaud 《Environmental science and pollution research international》2013,20(7):4509-4519
Extracellular polymeric substances (EPS) were extracted from four anaerobic granular sludges with different procedures to study their involvement in biosorption of metallic elements. EPS extracts are composed of closely associated organic and mineral fractions. The EPS macromolecules (proteins, polysaccharides, humic-like substances, nucleic, and uronic acids) have functional groups potentially available for the binding of metallic elements. The acidic constants of these ionizable groups are: pK a1 (4–5) corresponding to the carboxyl groups; pK a2 (6–7) corresponding to the phosphoric groups; pK a3 (8–10) and pK a4 (≈10) corresponding to the phenolic, hydroxyl, and amino groups. The polarographic study confirms the higher affinity of the EPS to bind to lead than to cadmium. Moreover, the binding of these metallic compounds with the EPS is a mix of several sorption mechanisms including surface complexation, ion exchange, and flocculation. Inorganic elements were found as ions linked to organic molecules or as solid particles. The mineral fraction affects the binding properties of the EPS, as the presence of salts decreases the EPS binding ability. Calcite and apatite particles observed on SEM images of EPS extracts can also sorb metallic elements through ion exchange or surface complexation. 相似文献
372.
Silvia Jerez Miguel Motas Jesús Benzal Julia Diaz Virginia Vidal Verónica D’Amico Andrés Barbosa 《Environmental science and pollution research international》2013,20(5):3300-3311
The presence of metals in the Antarctic environment is principally a natural phenomenon caused by geochemical characteristics of the region, although some anthropogenic activities can increase these natural levels. Antarctic penguins present several of the characteristics of useful sentinels of pollution in Antarctica such as they are long-lived species situated at the top of food web. The concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd, and Pb were determined by inductively coupled plasma–mass spectrometry in samples of liver, kidney, muscle, bone, feather, and stomach contents of gentoo, chinstrap, and Adélie penguin (12 adults, five juveniles) from carcasses of naturally dead individuals collected opportunistically in the Antarctic Peninsula area. The obtained results showed that accumulation and magnification of several elements can be occurring, so that Cd and Se reached levels potentially toxic in some specimens. The presence of human activities seems to be increasing the presence of toxic metals such as Mn, Cr, Ni, or Pb in penguins. 相似文献
373.
374.
Brendan C. O’Kelly 《Journal of the Air & Waste Management Association (1995)》2013,63(6):765-771
Abstract More stringent controls on the quality of wastewater discharges have given rise to increasing volumes of sewage sludge for disposal, principally to land, using either land-spreading or sludge-to-landfill operations. Current sludge-to-landfill methods generally involve mixing the concentrated sludge with other solid waste in municipal landfills. However, stricter waste disposal legislation and higher landfill taxes are forcing the water industry to look for more efficient disposal strategies. Landfill operators are also increasingly reluctant to accept sludge material in the slurry state because of construction difficulties and the potential for instability of the landfill slopes. The engineering and drying properties of a municipal sewage sludge are presented and applied, in particular, to the design, construction, and performance of sewage sludge monofills. Sludge handling and landfill construction are most effectively conducted within the water content range of 85% water content, the optimum water content for standard proctor compaction, and 95% water content, the sticky limit of the sludge material. Standard proctor compaction of the sludge within this water content range also achieves the maximum dry density of ~0.56 tonne/m3, which maximizes the storage capacity and, hence, the operational life of the landfill site. Undrained shear strength-water content data (pertinent to the stability of the landfill body during construction) and effective stress-strength parameters, which take into account the landfill age and the effects of ongoing sludge digestion, are presented. Landfill subsidence, which occurs principally because of creep and decomposition of the solid organic particles, is significant and continues indefinitely but at progressively slower rates. 相似文献
375.
The main tool that the ECB uses to influence monetary policy is through the short-term refinancing rate, a change in the short-term interest rate can in turn cause the whole yield curve to shift. In addition to central bank announcements, interbank rates such as Euribor are also influenced by, forward guidance from the ECB, various macroeconomic events, liquidity in the money markets and the perceived credit worthiness of financial institutions. Forward rates are usually used by policy makers and market practitioners to examine expectations, but options provide additional information about the uncertainty of these expectations, particularly future jump expectations. This research examines the jump characteristics of the 3-month Euribor futures contract and its corresponding futures option contracts using both a jump diffusion model with a Bernoulli jump distribution and option-implied parameters using a jump diffusion process with Poisson distribute. We find that both the Bernoulli jump analysis of historical data and implied jump diffusion model succinctly capture diffusion volatility, jumps and jump size. Using a regression analysis to examine the effect of ECB refinancing rate monetary policy announcements on the 3-month Euribor and the associated jump parameters, we find a significant relationship between ECB announcements and the probability of a jump in Euribor. Regression coefficients on the implied jump amplitude parameters suggest that the market correctly anticipates the direction of the rate announcement suggesting option-implied jump parameters can predict, to some extent, ECB announcements. However, our results also show that there is significant uncertainty before the announcements, and this implies that monetary policy communication is not having the full desired effect. 相似文献
376.
Valuing New Jersey’s Ecosystem Services and Natural Capital: A Spatially Explicit Benefit Transfer Approach 总被引:3,自引:0,他引:3
Shuang Liu Robert Costanza Austin Troy John D’Aagostino Willam Mates 《Environmental management》2010,45(6):1271-1285
We intend to estimate the value of ecosystem services in the U.S. State of New Jersey using spatially explicit benefit transfer.
The aggregated net rent, a conservative underestimate for the total economic value of the state’s natural environment, ranged
from 11.6 to11.6 to 19.6 billion/year, conditional on how inclusive we were in selecting the primary studies used to calculate
the central tendency values to transfer. In addition to calculating the range, mean, and standard deviation for each of 12
ecosystem services for 11 Land Use/Land Cover (LULC) types, we also conduct a gap analysis of how well ecosystem service values
are represented in the literature. We then map these values by assuming a mean value for each LULC and apply this to spatial
data. As to sensitivity analysis, we calculate the net present value of New Jersey’s natural environment utilizing three different
methods of discounting. These research results provide a useful, albeit imperfect, basis for assessing the value of ecosystem
services and natural capital, and their comparison with the value of conventional human and built capitals. 相似文献
377.
Rachele Pucciariello Maurizio D’Auria Vincenzo Villani Gaetano Giammarino Giuliana Gorrasi Galia Shulga 《Journal of Polymers and the Environment》2010,18(3):326-334
Polymer blends between lignin, a natural, widely available, no-cost material, and Poly(ε-caprolactone) (PCL), a biodegradable
polymer, have been prepared using the ‘clean’, friendly to the environment, technique of the High Energy Ball Milling (HEBM).
Two kinds of lignin have been used, Straw lignin, obtained through the Steam Explosion process (SE lignin), and/or Lignosulphonated
one (LS lignin). The tensile mechanical tests have shown that, at certain specific compositions, the blends, in particular
those with both SE and LS lignin, have good mechanical properties. In particular, by varying the blend composition it is possible
to obtain materials with tuneable properties, therefore useful for different applications. Dynamic-Mechanical-Thermal Analysis
(DMTA) reveals substantial immiscibility of the blends. Experiments of UV irradiation show that lignin acts as an UV stabilizer
for PCL. The effect is higher with SE lignin, likely due to its low molecular weight, which allows the short lignin chains
to diffuse more easily within the amorphous regions of PCL. 相似文献
378.
Manuel Dall’Osto Roy M. Harrison Eleanor J. Highwood Colin O’Dowd Darius Ceburnis Xavier Querol Eric P. Achterberg 《Atmospheric environment (Oxford, England : 1994)》2010,44(26):3135-3146
Mineral dust is an important aerosol species in the Earth’s atmosphere and has a major source within North Africa, of which the Sahara forms the major part. Aerosol Time of Flight Mass Spectrometry (ATOFMS) is first used to determine the mixing state of dust particles collected from the land surface in the Saharan region, showing low abundance of species such as nitrate and sulphate internally mixed with the dust mineral matrix. These data are then compared with the ATOFMS single particle mass spectra of Saharan dust particles detected in the marine atmosphere in the vicinity of the Cape Verde islands, which are further compared with those from particles with longer atmospheric residence sampled at a coastal station at Mace Head, Ireland. Saharan dust particles collected near the Cape Verde Islands showed increased internally mixed nitrate but no sulphate, whilst Saharan dust particles collected on the coast of Ireland showed a very high degree of internally mixed secondary species including nitrate, sulphate and methanesulphonate. This uptake of secondary species will change the pH and hygroscopic properties of the aerosol dust and thus can influence the budgets of other reactive gases, as well as influencing the radiative properties of the particles and the availability of metals for dissolution. 相似文献
379.
The risk of erroneous regulation in multilevel normative environmental chains, at the federal, regional, and lower levels,
down to the corporate one, has been studied. This risk has been demonstrated to increase unacceptably rapidly in the framework
of the existing system of “unconditional acceptance” of normative standards. To mend the situation, it is necessary to use
the “conditional acceptance” model by regarding post hoc decisions made at higher levels as a priori ones at the next (lower)
levels. A strategy of environmentally and economically balanced corporate regulation of nature management through minimization
of the losses resulting from both excessive caution and breaching the existing regulations has been proposed. This system,
combined with the European approach to nature conservation, requires that the “riskless” regulation should be abandoned and
is expected to improve the parameters of nature management quality by three to four orders of magnitude. 相似文献
380.
The adaptive role of resistance formed in housefly larvae exposed to different stress factors, namely Bitoxibacillin, Malathion,
and high and low temperatures, has been estimated. Comparison of biotic parameters in the original line and in all selected
(derivative) lines indicates that the resistance to stress factors formed in the derivative lines due to selection over 25
generations does not always coincide with the improvement of their adaptation potential. 相似文献