查看更多>>摘要：The contents for six elements (Ba, Cu, Ni, Pb, V and Zn) have been assayed in soils of Manresa, an area famous for its environmental sceneries in Central Catalonia region. This area is affected by a rapid transition from a traditionally agricultural-based economy to an increasingly industrial-based economy, and has formed a complete industrial structure. Twenty-seven soils (topsoil and subsoil) were sampled and heavy metals concentrations were analysed with an inductively coupled plasma-mass spectrometer (ICP-AES) after acid digestion with HNO3 and HCl and Xray fluorescence (XRF). The background values, calculated after the removal of concentrations above the upper whisker for studied metals were in mg.kg(-1): Ba: 904, Cu: 43.9, Ni: 38.7, Pb: 35.4, V: 110 and Zn: 131. The enrichment factor also shows enriched samples for Cu, Pb and Zn. The degree of soil contamination was assessed on the basis of geoaccumulation index and upper whisker method. Five percent of the soils was contaminated by at least one trace metal. The heavy metal showing the greatest number of samples with slight enrichment anomalies was Pb. The following data sets were influenced mainly by natural element dispersion and accumulation processes. Only Cu and Pb should be associated to anthropogenic pollution. However, Cu, Pb and Zn are grouped in very similar way with a general pattern increase in the NE direction for Pb and Zn and N for Cu. The relationships between the X-ray fluorescence and aqua regia methods were highly significant for Cu, Ni, Pb and Zn.
查看更多>>摘要：One of the pollutants leading to heavy metal pollution is the lead element. The studies on exposure of fish to lead have shown that this exposure leads to negative effects on body weight, and digestive enzymes and lipase. In humans, the symptoms of chronic lead toxicity are renal malfunction, anemia, brain and liver damage, cancer, hyperactivity, and general psychological impairment. For struggling with this heavy metal contamination, we have a useful tool named "Zeolite". Zeolites are used in many fields such as agriculture, metal industry, energy sector, manufacturing industry, water treatment, animal husbandry, struggling with environmental pollution, and etc.
查看更多>>摘要：The effects of soil temperature, moisture, and nitrogen deposition on temperature sensitivity of soil respiration (Q(10)) in four forests types within the Three Gorges area of China were studied. We measured soil respiration (Rs) and soil temperature (T-5), and moisture (W-5) at 5 cm soil depth and experimentally added three levels of soil nitrogen.
查看更多>>摘要：China is facing the threat of severe soil water erosion and the pressure from the second largest poor population in the world. The spatial relationship between the poor regions and soil water erosion would help us to identify the link between poverty and soil erosion. The spatial nexus between the administrative region of 592 national poor counties (NPCs) and soil water erosion in China were analyzed in the present study. The results showed that most of NPCs were closely distributed. The spatial pattern of NPCs implied the effects of drastic hazards on the poor could be regional and widespread. The large area of China is suffering from light water erosion and only the Loess Plateau was severely eroded. There were 51.7%, 41.6%, 14.7%, and 9.3% of NPCs, which had light water erosion, medium water erosion, intense water erosion, and serious (more intense and severer) water erosion, respectively. Similarly, 69.8% of the NPCs had environmental problems because of soil water erosion. The results showed that there is correlation between the distributions of soil water erosion and poverty in China. The linear regression between the mean income of farmers and the proportion of soil erosion area showed a negative relationship at a significant level (p<0.001). Further studies should pay more attention to the linkage between poverty and soil erosion for efficient soil erosion and poverty reduction.
查看更多>>摘要：The main objective of this study was to evaluate the spatial distribution and ecological risk of the heavy metals in soils around the industrial non-point source in the western town of Yixing city, an area with intensive industrialization in Yangtze River Delta of China. Investigated were the elements of Cd, Cr, Cu and Pb in topsoil with different distances in all the four directions from the industrial town (east, west, south, and north direction, respectively). Results show that Cd, Cr, Cu and Pb element are slightly accumulated, appreciably higher than the background values. The heavy metals concentrations in the west direction evidently exceed in the other three directions. The mainly reason is due to the subtropical monsoon climate and a large amount of discharged waste situated in the west of industrial town. This study also finds that almost all heavy metals show low correlation with the distance in the westward direction but significantly correlation with the increasing distance in the east direction. It is because of a combined effect of heavy metals in soils around non-point source. However, compared with point source, a decreasing trend with increasing distance due to non-point source is not evident, but the polluted territorial scope is wider. By means of correlation analysis, trace metals source in different directions is different around the industrial non-point source. Pb and Cu contaminants are the mainly polluted source in all four directions, especially in the western and eastern direction. Moreover, there are many industrial Cr contaminants in the northward direction and Cd contaminant at the south side of the industrial town is one of mainly contamination sources. The ecological risk assessment results show that all the soil heavy metals around non-point source are at low or moderate risk by the use of catastrophe progression method. Due to the combined effect of soil heavy metals, the ecological risk indices do not evidently change with the increasing distance in all the four directions. It is concluded that the ecological risk due to non-point source is wider than that due to point source.
查看更多>>摘要：Non-point source phosphorus (P) is a major limiting factor for freshwater eutrophication, it has attracted more and more attention in China. This study investigated P sorption and desorption of 10 soils P runoff from the headwater watershed of the Miyun reservoir. The results show that the rapid sorption of P from soil (with an average 49% occurring in the initial 30 min of reaction). P sorption capacity were influenced by soil organic matter, metal hydroxides, calcium, and clay contents. Calculated Langmuir parameters EPC0 and K, indicated a propensity for soil to release P. Erosion material derived from soils with a low EPC0 (<0.02 mg PL-1) acted as a sink for P and that derived from soils with a large EPC0 acted as a source of P. Rainfall runoff experiment were conducted to monitor soil erosion in June to September 2008 (wet season) from 22 plots in the Shixia watershed. Soils derived from different land-use types have varied P sorption capacities with that of soil from corn fields and riverbed was significantly higher than that from forest and grass areas. This study showed that soil properties can determine of a specific soil can be a sink or source of P to runoff and that actual P runoff can be described by these properties.
查看更多>>摘要：The aim of this research was to determine the effects of LED and fluorescent lights on micro-algal growth in a photo-bioreactor (PBR). All parameters and the illumination source (wavelength) were kept the same for the growth of Chlorella kessleri (UTEX 398), Botryococcus braunii (UTEX 572), and Synechococcus leopoliensis (UTEX B 625) microalgae in closed PBRs. Red LED, blue LED and white fluorescent lights were used as the illumination sources for the PBRs. Each light source was used to grow all three algal species. The data collected from the experiments were analyzed using ANOVA. The results, after a period of eight days of growth, showed that red LED light was the most efficient illumination source for producing the highest number of cells with the highest weight. However, additional trials should be carried out in the light dark/cycle to define the most effective illumination sources.
查看更多>>摘要：It has been evidenced that micro-RNAs, a class of small non-coding RNAs, are key regulators responding to heavy metal stress. Up to date, identification and characterization of micro-RNAs responding to heavy metal stress in gonads of sea urchin have not been fully elucidated. In this study, the expressional variation of micro-RNAs between normal sea urchin gonads and that stressed by 0.1 mM ZnSO4 for 12 h was compared utilizing microarray assay. The results showed 279 micro-RNAs were detected in control gonads, while 103 in Zn-stressed sample, indicating that Zn treatment decreased the expression level of micro-RNAs. In addition, 36 micro-RNAs expressed significantly varied between control and Zn-treated gonads including 16 down- and 20 up-regulated micro-RNAs. Prediction and functional annotation of targets of these 36 micro-RNAs uncovered that micro-NAs play roles in a broad range of physiological processes under Zn stress, such as Zn transporter, DNA methylation and histone modification, as well as the chaperones binding to unfold proteins, highlighting the potential roles of sea urchin micro-NAs in responding to heavy metal stress.
查看更多>>摘要：The aim of this study was to evaluate the effect of wet and microwave digestion methods on multi elements determination by inductively coupled plasma - optical emission spectroscopy in mushroom samples collected from selected regions of Sakarya, Turkey during 2011. Trace elements levels such as Ba, Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, V and Zn in six edible mushroom species (Agaricus bisporus, Agaricus subrufescens, Hygrocybe sp., Lactarius delicious, Lepiota bruneoincarneta and Pleurotus eryngii) were determined after wet and microwave digestions. Apple leaves standard reference material (NIST SRM 1515) was used for validation of the proposed method. The microwave digestion method well prevents sample from the secondary contamination, provides a more accuracy and needs a shorter time than wet ashing. The contents of the hazardous trace elements are well below the prescribed limits of World Health Organization.
查看更多>>摘要：In this study, a straw-based, environmental friendly and low-cost adsorbent was used to remove sulfur dioxide (SO2) from flue gas. We investigated the effects of preparation conditions, such as catalyst dosage, the amine agent, and amine agent concentration on SO2 adsorption performance. Regeneration performances were also explored. Experimental results indicated that modified Straw-NH had a high SO(2)adsorption capacity (similar to 130 mg/g) which was very close to activated carbon and can be regenerated at 120 degrees C in a nitrogen atmosphere. Additionally, after five adsorption/regeneration cycles, the SO2 adsorption capacity remained at a relatively high level. Adsorbent properties were characterized using Brunauer-Emmett-Teller (BET), elemental analysis, Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). This study indicated that modified Straw-NH may be an attractive practical alternative for SO2 removal.
NETL
NSTL