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201.
TiO_2/EP光催化降解水体中微污染磺胺嘧啶的研究 总被引:1,自引:1,他引:0
制备了膨胀珍珠岩(EP)为载体的TiO2催化剂(TiO2/EP),对使用较为广泛的抗生素磺胺嘧啶(SDZ)进行了光催化降解研究,探讨了TiO2的负载量、溶液的初始浓度、初始pH、无机离子(HCO3-、SO42-和Cl-)和腐殖酸(HA)对SDZ降解效果的影响。结果表明:SDZ的光催化降解符合一级反应动力学方程;当TiO2最佳负载量为20 wt%,SDZ浓度为5 mg/L,pH=6.7,紫外光照射强度为1 000μW/cm2,反应时间为45 min时,SDZ的降解率达到96%;HCO3-在低浓度时能促进SDZ的光催化降解,高浓度时促进作用不明显;SO42-和Cl-对SDZ的光催化降解有轻微的抑制作用;HA对SDZ光催化降解有显著的抑制作用,浓度越高,抑制作用越强。UV-TiO2/EP是一种去除水体中微污染SDZ的有效方法。 相似文献
202.
203.
L.Q. Xu L.G. Sun H. Yan Y.H. Luo Y.H. Wang 《Journal of environmental radioactivity》2010,101(5):362-368
Several natural and anthropogenic radionuclides (210Pb, 226Ra and 137Cs) in guano-phosphatic coral sediments and pure guano particles collected from Ganquan, Guangjin, Jinqing and Jinyin Islands of the Xisha archipelago, South China Sea, were analyzed. The Constant Initial Concentration (CIC) model and the Constant Rate of Supply (CRS) model were applied for age calculation. The average supply rate of 210Pb was 126 Bq m−2 a−1, very close to the flux of northern hemisphere average (125 Bq m−2 a−1). The activities of anthropogenic radionuclides in the sediments were very low, indicating that human nuclear tests did not notably impact this region. The main source of radionuclides in the sediments was from atmospheric precipitation, and the organic matter derived from plant and produced by nutrient-rich guano could further enhance them. 相似文献
204.
205.
Significantly high radiation level and radionuclide concentration along Quilon beach area of coastal Kerala have been reported by several investigators. Detailed gamma radiation level survey was carried out using a portable scintillometer. Detailed studies on radionuclides concentration in different environmental matrices of high background areas were undertaken in the coastal areas of Karunagapalli, Kayankulam, Chavara, Neendakara and Kollam to study the distribution and enrichment of the radionuclides in the region. The absorbed gamma dose rates in air in high background area are in the range 43-17,400 nGyh−1. Gamma radiation level is found to be maximum at a distance of 20 m from the sea waterline in all beaches. The soil samples collected from different locations were analysed for primordial radionuclides by gamma spectrometry. The activity of primordial radionuclides was determined for the different size fractions of soil to study the enrichment pattern. The highest activity of 232Th and 226Ra was found to be enriched in 125-63 μ size fraction. The preferential accumulation of 40K was found in <63 μ fraction. The minimum 232Th activity was 30.2 Bq kg−1, found in 1000-500 μ particle size fraction at Kollam and maximum activity of 3250.4 Bq kg−1 was observed in grains of size 125-63 μ at Neendakara. The lowest 226Ra activity observed was 33.9 Bq kg−1 at Neendakara in grains of size 1000-500 μ and the highest activity observed was 482.6 Bq kg−1 in grains of size 125-63 μ in Neendakara. The highest 40K activity found was 1923 Bq kg−1 in grains of size <63 μ for a sample collected from Neendakara. A good correlation was observed between computed dose and measured dose in air. The correlation between 232Th and 226Ra was also moderately high. The results of these investigations are presented and discussed in this paper. 相似文献
206.
B. Collange M. Rault Y. Capowiez 《Environmental pollution (Barking, Essex : 1987)》2010,158(6):2266-2272
Assessment of wildlife exposure to organophosphorus (OP) pesticides generally involves the measurement of cholinesterase (ChE) inhibition, and complementary biomarkers (or related endpoints) are rarely included. Herein, we investigated the time course inhibition and recovery of ChE and carboxylesterase (CE) activities in the earthworm Lumbricus terrestris exposed to chlorpyrifos, and the ability of oximes to reactivate the phosphorylated ChE activity. Results indicated that these esterase activities are a suitable multibiomarker scheme for monitoring OP exposure due to their high sensitivity to OP inhibition and slow recovery to full activity levels following pesticide exposure. Moreover, oximes reactivated the inhibited ChE activity of the earthworms exposed to 12 and 48 mg kg−1 chlorpyrifos during the first week following pesticide exposure. This methodology is useful for providing evidence for OP-mediated ChE inhibition in individuals with a short history of OP exposure (≤1 week); resulting a valuable approach for assessing multiple OP exposure episodes in the field. 相似文献
207.
Ge Yuan Chen Chengrong Xu Zhihong Eldridge Simon M. Chan Kwong Yin He Yan He Ji-Zheng 《Environmental science and pollution research international》2010,17(3):807-815
Background, aim, and scope
Current Australian legislation permits the beneficial application of grease trap waste (GTW) to agricultural soil, viewing it as a beneficial source of organic matter and soil conditioner containing no/low amounts of metals or pathogenic organisms. However, little is known about the influence of GTW on soil bacterial community. A field experiment was established at Menangle in south western Sydney in Australia to quantitatively assess the impacts of different types (GTW CO and GTW CL) and amounts of GTW application on the soil bacterial community and diversity. Furthermore, a municipal solid waste (MSW) compost was simultaneously examined to compare against the other organic wastes. Knowledge about the shifts in microbial community structure and diversity following the applications of organic wastes could help to evaluate the ecological consequences on the soil and thus to develop sound regulatory guidelines for the beneficial reuse of organic wastes in agricultural lands. 相似文献208.
Mobility of radium and trace metals in sediments of the Winterbeek: Application of sequential extraction and DGT techniques 总被引:1,自引:0,他引:1
For several decades, phosphate ores containing 226Ra as well as several trace metals have been processed in Belgium to produce calcium phosphate for use in cattle food. The waste water is discharged in two small rivers, the Laak and the Winterbeek.In this study, the levels of 226Ra and trace metals in surface water and sediments of the Winterbeek were investigated and the mobility of these compounds was assessed using DGT (Diffusive Gradient in Thin Films) and sequential extraction techniques.The concentrations of 226Ra and trace metals in water and sediment indicate a decreasing trend in inputs to the Winterbeek.The mobility of 226Ra, assessed by DGT, is related to the reductive mobilization of Fe. The sequential extraction technique shows that at some stations an important fraction of 226Ra is found to labile sediment phases.Diffusive 226Ra sediment fluxes, are however, relatively small and have only a minor contribution to the water column concentration of 226Ra. 相似文献
209.
采用浸渍法制备了CuO/BiVO4光催化剂,通过X射线衍射(XRD)、热重/差示扫描量热(TG/DSC)和傅立叶红外光谱(FTIR)对其进行了表征,并在可见光照射下考察了其光催化氧化亚甲基蓝(MB)的动力学特性。结果表明,Cu的掺杂并未改变BiVO4的晶型结构;Cu(NO3)2/BiVO4在热处理(30~300℃)过程中,NO3-已经完全分解,Cu最终以CuO的形式存在于CuO/BiVO4光催化剂体系中;掺杂不同量Cu的CuO/BiVO4中的Cu2+/Bi+(摩尔比)实测值与理论值相近,该系列光催化剂的合成过程具有较高的可信度;在可见光照射下,CuO/BiVO4光催化降解MB反应符合表观一级反应动力学特征;当Cu2+/Bi+为0.050时,反应动力学速率常数(k)达到最高值(0.4334h-1),此时的k比单体BiVO4作用下的提高了1.04倍;由于异质结的存在,CuO/BiVO4与单体BiVO4相比,电子和空穴的利用率大大增加,使得CuO/BiVO4的光催化活性较单体BiVO4有了大幅度提高。 相似文献
210.
An Estimation of the Effects of China’s Priority Forestry Programs on Farmers’ Income 总被引:1,自引:0,他引:1
In the late 1990s, the Chinese government initiated some new programs and consolidated other existing ones of ecological restoration and resource development in its forest sector, and renamed them as “Priority Forestry Programs,” or PFPs. They include the Natural Forest Protection Program (NFPP), the Sloping Land Conversion Program (SLCP), the Desertification Combating Program around Beijing and Tianjin (DCBT), the Shelterbelt Development Program (SBDP), and the Wildlife Conservation and Nature Reserve Development Program (WCNR). In addition to improving the environmental and resource conditions, a frequently reiterated goal of these PFPs is to increase rural households’ income, therefore discussing why looking at rural household income impacts might be an important part of forest program evaluation. Thus, an interesting and important question is: How has implementing the PFPs affected the farmers’ income and poverty status? This article addresses this question using a fixed-effects model and a panel dataset that covers 1968 households in four provinces for ten consecutive years (1995–2004). The empirical evidence indicates that their effects are mixed. The SLCP, the SBDP, and the NFPP have made positive impact and, by far, the SLCP has the largest effect. But the WCNR and the DCBT still have not had a pronounced overall effect due to their short time span of execution, even though they may have exerted certain influence at the margin. Notably, the impact of the WCNR, if any, is negative. 相似文献