酸化碱渣对氨氮的吸附和解吸性能

研究了氨氮质量浓度、体系温度、时间、酸化碱渣溶液的pH等对酸化碱渣吸附氨氮性能的影响,比较了作为解吸剂的蒸馏水和NaCl溶液对氨氮的解吸效果。在选定的实验条件下,酸化碱渣对氨氮的最大吸附量可达13．9mg／g。氨氮吸附量随其质量浓度的增加而增大、随体系温度的升高而降低,酸化碱渣溶液的pH对吸附性能的影响可以忽略。酸化碱渣表面吸附作用力主要为偶极间力和氢键力,吸附过程可用一级动力学方程模拟。NaCl溶液对氨氮的解吸效果好于蒸馏水,最大解吸率为25．7％。     

Impact of land use and land cover changes on ecosystem services in Menglun, Xishuangbanna, Southwest China

Changing the landscape has serious environmental impacts affecting the ecosystem services, particularly in the tropics. In this paper, we report changes in ecosystem services in relation to land use and land cover over an 18-year period (1988--2006) in the Menglun Township, Xishuangbanna, Southwest China. We used Landsat TM/ETM and Quickbird data sets to estimate changes in ten land use and land cover categories, and generalized value coefficients to estimate changes in the ecosystem services provided by each land category. The results showed that over the 18-year period, the land use and land cover in the study area experienced significant changes. Rubber plantations increased from 12.10% of total land cover to 45.63%, while forested area and swidden field decreased from 48.73 and 13.14 to 27.57 and 0.46%, respectively. During this period, the estimated value of ecosystem services dropped by US $11.427 million (approximately 27.73%). Further analysis showed that there were significant changes in ecological functions such as nutrient cycling, erosion control, climate regulation and water treatment as well as recreation; the obvious increase in the ecological function is provision of raw material (natural rubber). Our findings conclude that an abrupt shift in land use from ecologically important tropical forests and traditionally managed swidden fields to large-scale rubber plantations result in a great loss of ecosystem services in this area. Further, the study suggests that provision of alternative economic opportunities would help in maintaining ecosystem services and for an appropriate compensation mechanisms need to be established based on rigorous valuation.     

The emergy analysis of loop circuit

Emergy analysis can analyze the resource utilization and environmental performance of a system. Loop circuit is a common structure in the process industry, but when emergy analysis is carried out to such structure, mistakes such as emergy double counting often occur. To avoid emergy double counting, two types of loop circuit-direct loop circuit and indirect loop circuit-are theoretically distinguished, and the methods to avoid such mistake are proposed. Finally, PVC production and vinyl acetate production are adopted to demonstrate the methods.     

Soil Quality Evolution After Land Use Change From Paddy Soil to Vegetable Land

A survey was done in 15 typical villages, 150 soil and 86 vegetable plant samples were taken in Jiaxin prefecture of the Taihu Lake region, northern Zhejian province. Results indicate that after 15–20 years land use changed from the paddy rice–wheat (or oilseed rape) double cropping system, to a continuous vegetable land has caused soil quality dramatic change. (1) Acidification: average soil pH was 5.4; about 61% of total samples were pH < 5.5. It was 0.9 units lower than 10 years ago with same upland vegetable cultivation and was 1.2 units lower than soil pH of paddy rice–wheat (or oilseed rape) rotation. (2) Fertilizer salt accumulation: the average salt content was 0.28%, among these about 36.2% of the total samples contained more than 0.3%. (3) Nitrate N and available phosphorus (P) over accumulation: on average it was 279 mg NO₃-N/kg, and 45–115 mg P/kg. Nitrate N four times higher and available P 4–10 times more than it is in present paddy rice–wheat rotation soils respectively. This has caused wide concern because of possible groundwater and well drinking water pollution by leached nitrate N and the P losses to water by runoff from vegetable lands induce surface water eutrophication.     

腐殖质含量对填料净化污水效能的影响

掺入与腐殖垃圾级配相同的砂配置腐殖质含量分别为1.09%、0.87%、0.65%、0.44%和0.01%的5种填料,装填0.5 m厚度的试验柱,构建人工快速渗滤系统处理生活污水,并测定饱和水力渗透系数,研究腐殖质含量对填料净化污水效能的影响。结果表明,在相同的水力负荷（1 m/d）和污染负荷下,5种腐殖质填料对COD和TP的平均去除率存在明显差异,腐殖质含量为1.09%、0.87%和0.65%的3种填料对COD的去除率较腐殖质含量为0.01%的填料均高出14%以上。腐殖质含量与TP去除率呈现正相关性。腐殖质含量最高的填料（1#）其初始K值最大达3.23×10^-2 cm/s,约为腐殖质含量最低的填料（5#）的5倍,其稳定运行时间最长。     

确立生态文明观逐步建立经济与环境融合机制

新世纪即将来临的时候,应当确立生态文明观并建立持续发展的技术体制。为了达到这个目的,必须探讨环境保护和经济发展相统一,还要重新审视我国环境政策框架。     

公害的演变与预防

在概述公害的发展与演变的基础上, 简要介绍了地方级应急意识与准备（ＡＰＥＬＬ） 计划的有关内容, 以及我国首家实施该计划的上海市的实施情况。     

生物泥浆反应器生物修复难降解有机物污染土壤的研究进展

生物泥浆反应器因其传质快、条件可控、修复效率高而在生物修复难降解有机物污染物土壤中得到广泛应用。综述了生物泥浆反应器生物修复土壤中难降解有机物所涉及的固液传质、气液传质和生物降解等主要去除机制,总结了3种去除机制的重要性;概括了国内外对生物反应器建模的研究进展,凝练了固液传质、气液传质和生物降解过程的基础模型;确定了生物泥浆反应器的重要参数,包括物理参数、生物参数和操作参数,并概括了各种参数的影响机理及其适宜范围。最后展望了生物泥浆反应器去除难降解有机物未来的研究方向,包括机制研究、微生物菌剂以及应用装备的智能化等。

     

Effects of nanopesticide chlorfenapyr on mice

The effects of chlorfenapyr nano preparation on mice were examined. The animals were administered with different doses of 4.84, 9.68, or 19.36?mg?kg^?1 of chlorfenapyr common preparation or nano preparation intraperitoneally (IP). Micronucleus (MN) test and comet assay (CA) experiments revealed that at the same dose, similar DNA damage in the peripheral blood lymphocytes of the mouse and chromosome damage in bone marrow cells of the mouse occurred with chlorfenapyr nano preparation; however, the severity of these effects was less than that found in common preparation. It is noteworthy that there were no differences in apoptotic ratio and live cell percentage in the liver cells of the mouse between these two pesticide formulations using flow cytometry. Data indicate that chlorfenapyr nanoformulation is less toxic to mouse cells than the common formulation.