利用铁改性方解石作为活性覆盖材料控制水体内源磷的释放

虽然利用方解石作为一种活性覆盖材料控制水体内源磷释放具有较好的应用前景,但是其控制底泥中磷释放的效率仍然有待进一步提高.鉴于此,本文采用铁盐对方解石进行改性试图制备一种除磷性能更好的底泥活性覆盖材料——铁改性方解石,进而通过批量实验考察了铁改性方解石对水中磷酸盐的去除性能,以及通过底泥培养实验考察了铁改性方解石活性覆盖控制水体内源磷释放的效率.结果发现,采用铁对方解石进行改性,可以显著提高材料对水中磷酸盐的去除能力.铁改性方解石投加量的增加,有利于水中磷酸盐的去除.增加初始磷浓度,铁改性方解石对水中磷酸盐的单位去除量随之增加,最大的单位磷去除量可以达到3.09 mg·g^-1.铁改性方解石覆盖可以有效地控制底泥中磷的释放,导致上覆水体中溶解态活性磷(SRP)浓度处于很低的水平.此外,铁改性方解石覆盖还可以促使底泥中少量的氧化还原敏感态磷(BD-P)和金属氧化结合态磷(NaOH-rP)向残渣态磷(Res-P)转变,使得底泥中磷的稳定性略微增强.固定到铁改性方解石覆盖层中的磷大多数(90.8%)以较为稳定和非常稳定的形态存在,且大部分磷以非生物可利用性磷形式存在,很难被...     

氢氧化镁对水体内源磷释放的控制作用

本研究首先通过批量实验考察了氢氧化镁对水中磷酸盐的吸附性能,再通过底泥模拟释放实验考察了氢氧化镁覆盖和添加控制底泥中磷向上覆水体释放的效果及机制.结果表明,氢氧化镁对水中磷酸盐具有良好的吸附能力,其投加量的增加有利于水中磷酸盐被其所吸附去除,与Langmuir模型相比,其对水中磷酸盐的等温吸附行为更适合采用Freundlich和Dubinin-Radushkevitch(D-R)模型加以描述.氢氧化镁覆盖可以有效地控制底泥中磷向上覆水体的释放,使得上覆水中SRP浓度处于较低的水平,即使覆盖层的结构完整性受到扰动破坏而导致覆盖材料与表层底泥的混合,氢氧化镁仍然可以有效地控制底泥中磷向上覆水体的释放.氢氧化镁覆盖和添加均可以有效地降低最上层(0～10 mm)底泥间隙水中SRP的浓度,这对于其覆盖和添加有效控制底泥中磷向上覆水体的释放是至关重要的.人工合成的氢氧化镁对水中磷酸盐的吸附性能优于商业购买的氢氧化镁,前者控制水体内源磷向上覆水体释放的效果也优于后者.以上结果显示,氢氧化镁是一种有希望用于控制水体底泥内源磷释放的活性覆盖和改良材料.     

Restorating marine coastal ecosystem health as a new goad for integrated catchment management in Tolo Harbour,Hong Kong,China

The paper demonstrates why it is necessary to take the restoration of marine coastal ecosystem health as a new goal for integrated catchment management, in coastal area of the Tolo Harbour. The present goal of integrated catchment management (ICM) in the Tolo Harbour is to meet with Water Quality Objectives. The performance of an ICM plan, Tolo Harbour Action Plan (THAP), is evaluated by using marine coastal ecosystem health indicators including stress indicators and responses indicators. Since the implementation of THAP in 1988, some significant reduction in pollution loading has been observed - reduction of 83 % of BOD load and 82 % of TN between 1988 and 1999. There has been an improvement in the health state of Tolo Harbour marine coastal ecosystem as evidenced in the trends of the physical, chemical and biological indicators, although some reverse fluctuations in some periods exist. However, this can only be considered as the first sign of the ecosystem health restoration, since ecosystem health co     

The littoral zone of lake okeechobee as a source of phosphorus after drawdown

Following a period of prolonged drought or intentional lake level drawdown, large littoral areas that once contained submersed aquatic vegetation (SAV) are reinundated when lake levels rise. A complete assessment of the contribution made by decomposing SAV to the in-lake phosphorus (P) concentration is important in both the management of Lake Okeechobee and understanding basic P processes. The P contribution to the open waters of Lake Okeechobee from a rapid inundation of exposed SAV was calculated by four methods: cores of field-desiccated SAV, cores of lab-desiccated SAV in the presence and absence of sediments, in situ decomposition, and sequential macrophyte harvesting. P releases, given such an episodic event, were similar among the four methods, ranging from 116±48 to 384±528 mg/m² in the absence of sediment. When SAV is in contact with sediment, which is the realistic field situation, the amount of P released was four times less (30±14 mg/m²) than in the absence of sediment. The calculated P releases would result in total P concentration increases in the lake from 2 to 15 μg/liter (upper 95% CI=2–25 μg/liter) in the absence of sediment; only 1 μg/liter increase was predicted when SAV released P in contact with sediment. Thus it is unlikely that a significant rise in total P concentrations in the limnetic zone of the lake would occur from the export of P released during the desiccation of SAV in the littoral-marsh zone during a drawdown.     

农药使用的危险性评价

提出了农药使用危险性的单项因素及综合评价方法。其中必评因素包括,农药用量,急性和慢性毒性,三致作用,农药在作物和土壤中的半衰期,鱼毒,蜂毒以及对眼肤的刺激作用;附加参数包括,农药挥发性,代谢增毒作用,生物浓缩系数和除草剂对后茬作物的毒性。评价注重农药用量和急性毒性,在对205种农药进行评价的基础上,提出了我国用量最大的5种杀虫剂属危险级。     

旅游城市环境规划优化方法与应用研究(Ⅱ)昆明旅游圈环境规划优化

将IFMOPOMTCE该模型应用于昆明市旅游圈旅游环境规划优化的实例当中，取得了较为成功的效果，并采用情景分析和交互式调整的方法制定出两种方案。通过比较分析确定出适合昆明旅游业持续发展的最优发展方案，为决策者提供了科学的决策依据，从而证明了该模型的实用性和可操作性。     

Prenatal diagnosis of pseudo arylsulphatase a deficiency

Prenatal diagnosis was performed on a pregnancy at risk for metachromatic leukodystrophy (MLD) in a family with the pseudo arylsulphatase A deficiency trait. Extracts of cultured amniotic fluid cells were deficient in arylsulphatase A indicating that the fetus was either affected with MLD or had the benign pseudodeficiency trait. In the cerebroside sulphate loading test, the at risk cells hydrolysed sulphatide like control cultured amniotic fluid cells implying that the fetus had pseudodeficiency. The pregnancy was carried to term and a male child was delivered. Placenta, urine and fibroblasts had very low activities of arysulphatase A. However, no sulphatide could be detected in urine and growing fibroblasts responded normally in the cerebroside sulphate loading test, suggesting pseudodeficiency. At 29 months, the infant is healthy and shows no stigmata of MLD. The prediction based on the results of the cerebroside sulphate loading test on cultured amniotic fluid cells appeared to be borne out.     

水质管理容量的计算

在借鉴大气总量控制箱模式的理论基础上，探讨了河流水质管理容量的计算方法和特点，并对河流水质管理容量在水环境保护中的应用进行了论述。     

环境压力指标及应用

 基于国家尺度的社会代谢物质流、地理面积、净生态面积和标准生态面积,构建出测度本国环境所承受的环境压力总量指标体系——环境载荷和环境压强;对中国、德国、荷兰、奥地利、日本和美国等6个国家的环境载荷和环境压强进行了若干年的实证计算和对比分析.结果表明,虽然美国的人均环境载荷、人均物质总需求及人均生态足迹赤字等均是各国最高者,其环境压强却处于低位,与奥地利相近;中国的人均指标虽然低,其以标准生态面积计算的环境压强却是6国中最高者;以环境压强指标测度,5个发达工业国的经济发展与本国环境压力之间在研究期显示出不同程度的“脱钩”关系,即本国环境压强并没有随经济总量的增长而增加;中国的环境压力却呈现明显的上升态势.同时就环境问题的公平性和环境压力指标的优缺点进行了简要讨论.     

江苏省泰兴市土地资源的人口承载量研究

从人群的营养水平和主粮、副食品消费结构的变化出发，分别估算和预测了１９９３年和２０００年江苏省泰兴市土地资源的人口承载量。结果表明，该市土地资源１９９３年可供１２０万人过上宽裕型生活，到２０００年可供９５万人过上小康型生活，其余三分之一以上人口的粮食需求要依靠市外供给。