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961.
Transport and degradation of propylene glycol in the vadose zone: model development and sensitivity analysis 总被引:1,自引:0,他引:1
D. Schotanus J. C. L. Meeussen H. Lissner M. J. van der Ploeg M. Wehrer K. U. Totsche S. E. A. T. M. van der Zee 《Environmental science and pollution research international》2014,21(15):9054-9066
Transport and degradation of de-icing chemical (containing propylene glycol, PG) in the vadose zone were studied with a lysimeter experiment and a model, in which transient water flow, kinetic degradation of PG and soil chemistry were combined. The lysimeter experiment indicated that aerobic as well as anaerobic degradation occurs in the vadose zone. Therefore, the model included both types of degradation, which was made possible by assuming advection-controlled (mobile) and diffusion-controlled (immobile) zones. In the mobile zone, oxygen can be transported by diffusion in the gas phase. The immobile zone is always water-saturated, and oxygen only diffuses slowly in the water phase. Therefore, the model is designed in a way that the redox potential can decrease when PG is degraded, and thus, anaerobic degradation can occur. In our model, manganese oxide (MnO2, which is present in the soil) and NO \(_{3}^{-}\) (applied to enhance biodegradation) can be used as electron acceptors for anaerobic degradation. The application of NO \(_{3}^{-}\) does not result in a lower leaching of PG nor in a slower depletion of MnO2. The thickness of the snowcover influences the leached fraction of PG, as with a high infiltration rate, transport is fast, there is less time for degradation and thus more PG will leach. The model showed that, in this soil, the effect of the water flow dominates over the effect of the degradation parameters on the leaching at a 1-m depth. 相似文献
962.
M. Lodenius U. Skarén P. Hellstedt E. Tulisalo 《Environmental monitoring and assessment》2014,186(1):325-333
Mercury concentrations were monitored in European otter (Lutra lutra), European polecat (Mustela putorius) and European pine marten (Martes martes) collected in Eastern Finland during the period 1972–2008. Otters mainly eat fish, which is an important reason to monitor the bioaccumulation of mercury in this predator. In this species, the highest concentrations were found in fur followed by liver and kidney, and the mercury concentrations increased with increasing age and body weight. Males showed in general higher concentrations than females of otters. The food of European polecat consists of small mammals, frogs, birds and insects from both aquatic and terrestrial food chains. The mercury concentrations were lower than in otters without significant differences related to body weight or sex. In European pine martens, the concentrations were rather evenly distributed except for two specimens with high concentrations. Also, concentrations of some other metals (Al, Cd, Cu, Fe, Mn, Ni, Pb and Zn) were analysed from liver samples of otter. Possible adverse effects of mercury on the Finnish populations of these mustelids are discussed. 相似文献
963.
J. C. Valdez-González U. J. López-Chuken J. L. Guzmán-Mar F. Flores-Banda A. Hernández-Ramírez L. Hinojosa-Reyes 《Environmental science and pollution research international》2014,21(9):5909-5916
Crops, particularly in the Northeast region of Mexico, have to cope with increasing soil salinization due to irrigation. Chloride (Cl?) concentration has been strongly related to enhance cadmium (Cd) uptake by plants due to increased solubility in the soil solution. The effect of irrigation with slightly saline water from a local well was evaluated in this work on the accumulation and translocation of Cd in Swiss chard (Beta vulgaris L.) grown in soil historically amended with stabilized sewage sludge under a regime of phosphorus and zinc fertilization. A factorial pot experiment was conducted with two phosphate fertilizer levels (PF, 0 and 80 kg ha?1 dry soil, respectively), two Zn levels (0 and 7 kg ha?1 dry soil), and two sources of water for irrigation deionized water (DW) and slightly saline well water (WW) from an agricultural site. Additionally, a human risk assessment for Cd ingestion from plants was assessed. Results showed that Cl? salinity in the WW effectively mobilized soil Cd and increased its phytoavailability. A higher level of Cd was found in roots (46.41 mg kg?1) compared to shoots (10.75 mg kg?1). Although the total content of Cd in the edible parts of the Swiss chard irrigated with WW exceeded permissible recommended consumption limit, bioavailable cadmium in the aboveground parts of the plant in relation to the total cadmium content was in the range from 8 to 32 %. Therefore, human health risks might be overestimated when the total concentration is taken into account. 相似文献
964.
Matching the trend seen among the major large rivers of the globe, the Amazon River and its tributaries are facing aquatic ecosystem disruption that is affecting freshwater habitats and their associated biodiversity, including trends for decline in fishery resources. The Amazon’s aquatic ecosystems, linked natural resources, and human communities that depend on them are increasingly at risk from a number of identified threats, including expansion of agriculture; cattle pastures; infrastructure such as hydroelectric dams, logging, mining; and overfishing. The forest, which regulates the hydrological pulse, guaranteeing the distribution of rainfall and stabilizing seasonal flooding, has been affected by deforestation. Flooding dynamics of the Amazon Rivers are a major factor in regulating the intensity and timing of aquatic organisms. This study’s objective was to identify threats to the integrity of freshwater ecosystems, and to seek instruments for conservation and sustainable use, taking principally fish diversity and fisheries as factors for analysis. 相似文献
965.
Fertilizer and sanitary quality of digestate biofertilizer from the co-digestion of food waste and human excreta 总被引:3,自引:0,他引:3
H.I. Owamah S.O. Dahunsi U.S. Oranusi M.I. Alfa 《Waste management (New York, N.Y.)》2014,34(4):747-752
This research was aimed at assessing the fertilizer quality and public health implications of using digestate biofertilizer from the anaerobic digestion of food wastes and human excreta. Twelve (12) kg of food wastes and 3 kg of human excreta were mixed with water in a 1:1 w/v to make 30-l slurry that was fed into the anaerobic digester to ferment for 60 days at mesophilic temperature (22–31 °C). Though BOD, COD, organic carbon and ash content in the feedstock were reduced after anaerobic digestion by 50.0%, 10.6%, 74.3% and 1.5% respectively, nitrogen, pH and total solids however increased by 12.1%, 42.5% and 12.4% respectively. The C/N ratios of the feedstock and compost are 135:1 and 15.8:1. The residual total coliforms of 2.10 × 108 CFU/100 ml in the digestate was above tolerable limits for direct application on farmlands. Microbial analysis of the digestate biofertilizer revealed the presence of Pseudomonas, Klebsiella, Clostridium, Bacillus, Bacteroides, Penicillum, Salmollena, and Aspergillus. Klebsiella, Bacillus, Pseudomonas, Penicillum and Aspergillus can boost the efficiency of the biofertilizer through nitrogen fixation and nutrient solubility in soils but Klebsiella again and Salmollena are potential health risks to end users. Further treatment of the digestate for more efficient destruction of pathogens is advised. 相似文献
966.
A. M. Razmi U. Lemmin D. Bouffard A. Wüest R. E. Uittenbogaard D. A. Barry 《Environmental Fluid Mechanics》2017,17(3):415-428
Numerical simulations were carried out to investigate gyres within open lacustrine embayments subjected to parallel-to-shore currents. In such embayments, gyre formation occurs due to flow separation at the embayment’s upstream edge. High momentum fluid from the mixing layer between the embayment and offshore flows into the embayment and produces recirculating flow. Systematic numerical experiments using different synthetic embayment configurations were used to examine the impact of embayment geometry. Geometries included embayments with different aspect ratios, depths and embayment corner angles. The magnitudes of the recirculation and turbulent kinetic energy (TKE) in the embayment vary significantly for angles in the range 40°–55°. Embayments with corner angles less than 50° have much stronger recirculation and TKE, other parameters remaining the same. The numerical findings are consistent with gyre formation observed in two embayments located in Lake Geneva, Switzerland, and thus help explain flow patterns recorded in lacustrine shoreline regions. 相似文献
967.
Satya Narayan H. M. Dani U. K. Misra 《Journal of environmental science and health. Part. B》2013,48(2):259-272
Abstract The effect of intracheally administered DDT (5 mg/100 g body weight) or endosulfan (1 mg/100 g body weight) for three cosecutive days have been studied on lipid metabolism of rat lung subcellular fractions. Both the insecticides did not affect the lung weight and the protein contents of microsomes, lamellar bodies and surfactant but significantly increased the phospholipid contents of microsomal and surfactant system. Most of the neutral lipid components of lung subcellular fractions were also increased by DDT or endosulfan treatments, except that of surfactant triglycerides which were decreased by DDT treatment. DDT or endosulfan both increased the incorporation of radioactive [methyl‐3H]choline into microsomal phosphatidylcholine (PC) and surfactant dipalmitoylphosphatidylcholine (DPPC) without affecting the incorporation of radioactive [methyl‐14C]methionine, showing the increased synthesis of PC via CDPcholine pathway. The results presented in this communication showed that DDT and endosulfan, the two different chloroinsecticides have similar effects on microsomal lipid metabolism but produce different biochemical manifestations on the secretion of surfactant phospholipids. 相似文献
968.
Antonella Soro Manfred Ayasse Marion U. Zobel Robert J. Paxton 《Behavioral ecology and sociobiology》2011,65(4):641-653
The ability to discriminate degrees of relatedness may be expected to evolve if it allows unreciprocated altruism to be preferentially
directed towards kin (Hamilton in J Theor Biol 7:1–16, 1964). We explored the possibility of kin recognition in the primitively eusocial halictid bee Lasioglossum malachurum by investigating the reliability of worker odour cues that can be perceived by workers to act as indicators of either nest
membership or kinship. Cuticular and Dufour’s gland compounds varied significantly among colonies of L. malachurum, providing the potential for nestmate discrimination. A significant, though weak, negative correlation between chemical distance
and genetic relatedness (r = −0.055, p < 0.001) suggests a genetic component to variation in cuticular bouquet, but odour cues were not informative enough to discriminate
between different degrees of relatedness within nests. This pattern of variation was similar for Dufour’s gland bouquets.
The presence of unrelated individuals within nests that are not chemically different from their nestmates suggests that the
discrimination system of L. malachurum is prone to acceptance errors. Compounds produced by colony members are likely combined to generate a gestalt colony chemical
signature such that all nestmates have a similar smell. The correlation between odour cues and nest membership was greater
for perceived compounds than for non-perceived compounds, suggesting that variability in perceived compounds is a result of
positive selection for nestmate recognition despite potentially stabilising selection to reduce variability in odour differences
and thereby to reduce costs derived from excessive intracolony nepotistic behaviour. 相似文献
969.
Honey U. K. Pillai K. A. Jayaraj M. Rafeeq K. J. Jayalakshmi C. Revichandran 《Environmental monitoring and assessment》2011,176(1-4):239-250
The study addresses the distribution and diversity of mesozooplankton near the active volcano-Barren Island (Andaman Sea) in the context of persistent volcanic signature and warm air pool existing for the last few months. Sampling was done from the stations along the west and east side of the volcano up to a depth of 1,000 m during the inter monsoon (April) of 2006. Existence of feeble warm air pool was noticed around the Island (Atm. Temp. 29°C). Sea surface temperature recorded as 29.9°C on the west and 29.6°C on the east side stations. High mesozooplankton biomass was observed in the study area than the earlier reports. High density and biomass observed in the surface layer decreased significantly to the deeper depths. Lack of correlation was observed between mesozooplankton biomass and density with chl. a. Twenty-three mesozooplankton taxa were observed with copepoda as the dominant taxa followed by chaetognatha. The relative abundance of chaetognatha considerably affected the copepod population density in the surface layer. A noticeable feature was the presence of cumaceans, a hyperbenthic fauna in the surface, mixed layer and thermocline layer on the western side station where the volcano discharges in to the sea. The dominant order of copepoda, the calanoida was represented by 52 species belonging to 17 families. The order poecilostomatoida also had a significant contribution. Copepods exhibited a clear difference in their distribution pattern in different depth layers. The families Calanidae and Pontellidae showed a clear dominance in the surface whereas small-sized copepods belonging to the families Clausocalanidae and Paracalanidae were observed as the predominant community in the mixed layer and thermocline layer depth. Families Metridinidae, Augaptilidae and Aetideidae were observed as dominant in deeper layers. 相似文献
970.
A new approach to investigate the interactions between sediment transport and ecotoxicological processes during flood events 总被引:1,自引:0,他引:1
Holger Schüttrumpf Markus Brinkmann Catrina Cofalla Roy M Frings Sabine U Gerbersdorf Markus Hecker Sebastian Hudjetz Ulrike Kammann Gottfried Lennartz Sebastian Roger Andreas Schäffer Henner Hollert 《Environmental Sciences Europe》2011,23(1):1-5