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Does the use of distiller’s dried grains with solubles (DDGS) in layer diets affect the nutrients digestibility and manure pollution by nitrogen and phosphorous?
2017
Abd El-Hack, Mohamed E. | El-Hindawy, Mohamed M. | Attia, Adel I. | Mahrose, Khalid M.
The objective of the current study was to examine the effect of the inclusion levels of distiller’s dried grains with solubles (DDGS) which partially and fully replaced soybean meal (SBM) in laying hen diets with or without enzyme or vitamin E supplementation on nutrients digestibility and excreted nitrogen and phosphorous. For these purposes, a total of 180 Hisex Brown laying hens at 22 weeks of age were randomly distributed into 15 treatment groups in a 5 × 3 factorial design experiment including five levels of DDGS (0, 5.5, 11, 16.5 and 22% replaced for the same percent of SBM which represents 0, 25, 50, 75 and 100% respectively in the diet) and three levels of feed additives (without, 250 mg enzyme/kg diet or 200 mg vitamin E/kg diet) through 22–42 weeks of age. Results revealed that digestion coefficient values of nutrients including DM, OM, CP, EE, NFE and CF were more preferable in hens fed diets involved 25% DDGS instead of SBM than that of the control diet and other treatment groups. In contrast, hens fed 100% substitution of DDGS caused significant (P ≤ 0.01) decrease in digestibility coefficients of all nutrients. The amount of daily excreted N was decreased in hens fed 25 or 50% DDGS substitution, whilst feeding 75 or 100% DDGS led to an elevation in N excretion. The proportion of excreted phosphorous was statistically (P ≤ 0.01) decreased as the level of DDGS increased. Generally, neither enzyme nor vitamin E supplementation had any significant effect on the studied parameters. It could be concluded that DDGS could be used up to 50% as a replacement of SBM (11% of the diet) without any adverse effects on nutrients digestibility. Laying hen farms using DDGS up to 25 or 50% substituted for SBM in its diets (5.5 or 11% of the diet) will have clearer environment of nitrogen and phosphorous pollution than others whose diets free of DDGS.
显示更多 [+] 显示较少 [-]Integration of cerium chemical forms and subcellular distribution to understand cerium tolerance mechanism in the rice seedlings
2017
Wang, Xue | Liu, Dongwu
Rare earth elements (REEs) accumulate in the soil and ecosystem. Cerium (Ce) is one of the main additives in REE-containing fertilizers. However, little information is available on Ce distribution patterns and chemical forms in rice. The subcellular distribution and chemical forms of Ce were investigated in the rice seedlings (Oryza sativa L., cv. Zhonghua 11) exposed to 0, 10, 20, 40, 80, and 160 μM Ce. The elongation of root and shoot was significantly inhibited by 20, 40, 80, and 160 μM Ce. Cerium was significantly accumulated in the cell walls, cell organelles, and soluble fractions of the roots and shoots with the increase of Ce concentrations. The concentrations of Ce in roots were significantly higher than shoots, and a large amount of Ce was stored in cell walls. In addition, Ce existed in the different chemical forms in the rice seedlings, and there were most insoluble oxalate or phosphate forms in roots. The subcellular distribution and chemical forms of Ce were closely associated with the metal tolerance and detoxification of rice.
显示更多 [+] 显示较少 [-]Simultaneous sulfide removal, nitrification, and electricity generation in a microbial fuel cell equipped with an oxic cathode
2017
Bao, Renbing | Zhang, Shaohui | Zhao, Li | Zhong, Liuxiang
With sulfide as an anodic electron donor and ammonium as a cathodic substrate, the feasibility of simultaneous sulfide removal, nitrification, and electricity generation was investigated in a microbial fuel cell (MFC) equipped with an oxic cathode. Successful simultaneous sulfide removal, nitrification, and electricity generation in this MFC were achieved in 35 days, with the sulfide and ammonium removal percent of 92.7 ± 1.4 and 96.4 ± 0.3%, respectively. The maximum power density increased, but the internal resistance decreased with the increase of feeding sulfide concentration from 62.9 ± 0.3 to 238.5 ± 0.2 mg S/L. Stable ammonium removal with complete nitrification, preparing for future denitrification, was obtained throughout the current study. Sulfide removal loading significantly increased with the increase of feeding sulfide concentration at each external resistance, but no significant correlation between sulfide removal loading and external resistance was found at each feeding sulfide concentration. The charge recovery and anodic coulombic efficiency (CE) significantly decreased with the increase of external resistance. High feeding sulfide concentration led to low anodic CE. Granular sulfur deposition was found on the anode graphite fiber. The appropriate feeding sulfide concentration for sulfide removal and sulfur deposition was deemed to be 178.0 ± 1.7 mg S/L, achieving a sulfur deposition percent of 69.7 ± 0.6%.
显示更多 [+] 显示较少 [-]Dynamic leaching behavior of geogenic As in soils after cement-based stabilization/solidification
2017
Li, Jiang-Shan | Wang, Lei | Tsang, Daniel C.W. | Beiyuan, Jingzi | Poon, C. S. (Chi-sun)
Cement-based stabilization/solidification (S/S) is a practical treatment approach for hazardous waste with anthropogenic As sources; however, its applicability for geogenic As-containing soil and the long-term leaching potential remain uncertain. In this study, semi-dynamic leaching test was performed to investigate the influence of S/S binders (cement blended with fuel ash (FA), furnace bottom ash (FBA), or ground granulated blast furnace slag (GGBS)) on the long-term leaching characteristics of geogenic As. The results showed that mineral admixtures with higher Ca content and pozzolanic activity were more effective in reducing the leached As concentrations. Thus, cement blended with FBA was inferior to other binders in suppressing the As leaching, while 20% replacement of ordinary Portland cement by GGBS was considered most feasible for the S/S treatment of As-containing soils. The leachability of geogenic As was suppressed by the encapsulation effect of solidified matrix and interlocking network of hydration products that were supported by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) results. The long-term leaching of geogenic As from the monolithic samples was diffusion-controlled. Increasing the Ca content in the samples led to a decrease in diffusion coefficient and an increase in feasibility for “controlled utilization” of the S/S-treated soils.
显示更多 [+] 显示较少 [-]Effects of prepartum sustained-release trace elements ruminal bolus on performance, colustrum composition and blood metabolites in Najdi ewes
2017
Abdelrahman, Mutassim M. | Aljumaah, Riyadh S. | Khan, Rifat Ullah
The aim of this study was to determine the effect of the supplementation of slow release bolus of selenium (Se), copper (Cu), zinc (Zn), cobalt (Co), phosphorous (P), manganese (Mn), and iodine (I) at late gestation (60 day prepartum) on performance of Najdi ewes and their newborn. Twenty Najdi ewes at late gestation were randomly selected from a herd raised under an intensive system and equally divided into two groups (control and treated). Blood samples were collected from ewes and newborns at parturition. Body weights of newborns were taken at birth, 30 and 60 days. A significant (P < 0.05) increase in Cu and Co in blood of dams treated with boluses with an increase (P < 0.05) in blood P, Zn, Cu, Co, and Se of their newborn lambs were observed. Creatinine and triglyceride were significantly (P < 0.05) low in treated newborn while urea was significantly (P < 0.05) high in the same group. In dams, significantly (P < 0.05) low concentration of triglyceride was observed. Body weight of lambs from treated group at 30 days was significantly (P < 0.05) higher when compared with the control. In conclusion, bolus of trace minerals at late gestation improved some mineral status of ewes and the newborns with higher body weight.
显示更多 [+] 显示较少 [-]Concentrations and inhalation risk assessment of short-chain polychlorinated paraffins in the urban air of Dalian, China
2017
Zhu, Xiuhua | Bai, Hao | Gao, Yuan | Chen, Jiping | Yuan, Heping | Wang, Longxing | Wang, Wei | Dong, Xuewei | Li, Xiaoxiao
The concentrations of short-chain polychlorinated paraffins (SCCPs) in the urban air of Dalian, China, were monitored from March to October 2010 and from September to October 2016 with active high-volume sampler. The total concentration of SCCPs (particulate phase + gas phase) ranged from 15.12 to 66.44 ng m⁻³, with an average of 30.26 ng m⁻³ in 2010, and 65.30 to 91.00 ng m⁻³, with an average of 78.15 ng m⁻³ in 2016. Hexa-chlorinated dodecane and hexa-chlorinated undecane are the predominant components in the gas phase, while octa-chlorinated undecane and hepta-chlorinated tridecane are dominant in the particulate phase. In 2010, 82.57–97.16% of the total SCCPs were found in the gas phase, except that in winter, where 63.11% of the total SCCPs were in the particulate phase; the air concentrations of SCCPs in gas phase were summer > autumn > spring > winter, which was positively correlated with the change of the average ambient temperature, while it was the contrary in particulate phase. In autumn, the gas phase and the total air concentration of SCCPs in 2016 were 2.57 times more than that in 2010, while the congener group patterns of SCCPs were similar. Spearman’s rank correlation analysis between the concentrations of SCCPs with meteorological parameters was conducted. The gas-particle distribution was examined through the relationship of the logarithm of the gas-particle partition coefficient with that of the subcooled vapor pressure and the octanol-air partitioning coefficient of SCCPs. Results indicated that the absorption mechanisms contributed more to the partitioning process. The exposure risk of SCCPs was evaluated, which illustrated that the estimated exposure of SCCPs via the outdoor environment in Dalian did not exceed the health concern threshold of the European risk assessment.
显示更多 [+] 显示较少 [-]Sorption of thiabendazole in sub-tropical Brazilian soils
2017
de Oliveira Neto, Odilon França | Arenas, Alejandro Yopasa | Fostier, Anne Hélène
Thiabendazole (TBZ) is an ionizable anthelmintic agent that belongs to the class of benzimidazoles. It is widely used in veterinary medicine and as a fungicide in agriculture. Sorption and desorption are important processes influencing transport, transformation, and bioavailability of xenobiotic compounds in soils; data related to sorption capacity are therefore needed for environmental risk assessments. The aim of this work was to assess the sorption potential of TBZ in four Brazilians soils (sandy, sandy-clay, and clay soils), using batch equilibrium experiments at three pH ranges (2.3–3.0, 3.8–4.2, and 5.5–5.7). The Freundlich sorption coefficient (K F) ranged from 9.0 to 58 μg¹–¹/ⁿ (mL) ¹/ⁿ g⁻¹, with higher values generally observed at the lower pH ranges (2.3–3.0 and 3.8–4.2) and for clay soils. The highest organic carbon-normalized sorption coefficients (KOC) obtained at pH 3.8–5.7 (around the natural pH range of 4.1–5.0) for both clay soils and sandy-clay soil were 3255 and 2015 mL g⁻¹, respectively. The highest correlations K F vs SOM (r = 0.70) and K F vs clay content (r = 0.91) were observed at pH 3.8–4.2. Our results suggest that TBZ sorption/desorption is strongly pH dependent and that its mobility could be higher in the studied soils than previously reported in soils from temperate regions.
显示更多 [+] 显示较少 [-]The impact of selected soil organic matter fractions on the PAH accumulation in the agricultural soils from areas of different anthropopressure
2017
Klimkowicz-Pawlas, Agnieszka | Smreczak, Bozena | Ukalska-Jaruga, Aleksandra
The level of 16PAH accumulation was determined in 75 soil samples collected from two agricultural regions of Poland corresponding to the smallest Polish administrative unit at the LAU 2 level. Both regions are characterised by similar territory and soil cover but different history of pollution and different pressure of anthropogenic factors. Overall accumulation of Σ16PAHs in the upper soil layer was within a wide range with the median value of 291 and 1253 μg kg⁻¹ for a non-contaminated and high anthropopressure region, respectively. Nearly 75 % of the total polycyclic aromatic hydrocarbon (PAH) pool was represented by high molecular four-to-six-ring compounds, deriving mainly from combustion sources. The total organic carbon (Cₒᵣg) and black carbon (BC) contents were the main parameters associated with the PAH accumulation in soils, and the level of the regional anthropopressure was considered a significant factor. The strongest links of PAHs/BC (r = 0.70, p ≤ 0.05) were found in the region of high anthropopressure, characterized by a relatively high content of BC (up to 45.3 g kg⁻¹), which tends to heavily adsorb hydrocarbons. In a region of low influence exerted by anthropopressure, the PAH/Cₒᵣg or PAH/BC relationships were not observed, which may suggest different diffuse sources of PAH origin and a dominant role of other organic matter fractions in retention of PAHs in soils.
显示更多 [+] 显示较少 [-]Biological and analytical techniques used for detection of polyaromatic hydrocarbons
2017
Kumar, Sunil | Negi, Sangeeta | Maiti, Pralay
Polycyclic aromatic hydrocarbons contain two or more fused benzene rings that are considered as cosmo-pollutants ubiquitously found in the environment. The identification and monitoring of polycyclic aromatic hydrocarbons (PAHs) are of great interests for rapid and on-site detection. Therefore, many analytical and biological techniques have been proposed for the qualitative and quantitative assessments of PAHs. Non-biological analytical techniques such as infrared, Raman, and fluorescence spectroscopies are commonly exploited as non-destructive techniques while gas chromatography (GC) and high-performance liquid chromatography (HPLC) with multiple detectors are extensively employed for the separation and detection of an analyte. Even though spectroscopy and chromatography are more accurate, convenient, and feasible techniques, often, these methods are expensive and sophisticated which require high maintenance cost. On the other hand, biological approaches, i.e., immunoassay, PCR, and microarray, offer comprehensive high-throughput specificity and sensitivity for a similar analyte. Biosensor- and immunoassay-mediated detections of PAHs have opened up new avenues in terms of low cost, rapid determination, and higher sensitivity. In this review, we have discussed the strengths and limitations of biological and analytical techniques that were explored for precise evaluation and were trusted at both the legislation and research levels.
显示更多 [+] 显示较少 [-]In situ remediation of tetrachloroethylene and its intermediates in groundwater using an anaerobic/aerobic permeable reactive barrier
2017
Liu, SheJiang | Yang, QinMing | Yang, YongKui | Ding, Hui | Qi, Yun
Tetrachloroethylene (PCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. Its chlorinated degradation by-products remain highly toxic. In this study, an anaerobic/aerobic permeable reactive barrier system consisting of four different functional layers was designed to remediate PCE-contaminated groundwater. The first (oxygen capture) layer maintained the dissolved oxygen (DO) concentration at < 1.35 mg/L in influent supplied to the second (anaerobic) layer. The third (oxygen-releasing) layer maintained DO concentration at > 11.3 mg/L within influent supplied to the fourth (aerobic) layer. The results show that 99% of PCE was removed, mostly within the second layer (anaerobic). Furthermore, the toxic by-products trichloroethylene (TCE), dichloroethylene (DCE), and vinyl chloride (VC) were further degraded by 98, 90, and 92%, respectively, in layer 4 (aerobic). Thus, the designed anaerobic/aerobic permeable reactive barrier system could control both PCE and its degradation by-products, showing great potential as an efficient remediation alternative for the in situ treatment of PCE-contaminated groundwater.
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