A dynamic hydrological Monte Carlo simulation model to inform decision-making at Lake Toolibin,Western Australia

Lake Toolibin, an ephemeral lake in the agricultural zone of Western Australia, is under threat from secondary salinity due to land clearance throughout the catchment. The lake is extensively covered with native vegetation and is a Ramsar listed wetland, being one of the few remaining significant migratory bird habitats in the region. Currently, inflow with salinity greater than 1000 mg/L TDS is diverted from the lake in an effort to protect sensitive lakebed vegetation. However, this conservative threshold compromises the frequency and extent of lake inundation, which is essential for bird breeding. It is speculated that relaxing the threshold to 5000 mg/L may pose negligible additional risk to the condition of lakebed vegetation. To characterise the magnitude of improvement in the provision of bird breeding habitat that might be generated by relaxing the threshold, a dynamic water and salt balance model of the lake was developed and implemented using Monte Carlo simulation. Results from best estimate model inputs indicate that relaxation of the threshold increases the likelihood of satisfying habitat requirements by a factor of 9.7. A second-order Monte Carlo analysis incorporating incertitude generated plausible bounds of [2.6, 37.5] around the best estimate for the relative likelihood of satisfying habitat requirements. Parameter-specific sensitivity analyses suggest the availability of habitat is most sensitive to pan evaporation, lower than expected inflow volume, and higher than expected inflow salt concentration. The characterisation of uncertainty associated with environmental variation and incertitude allows managers to make informed risk-weighted decisions.     

Distribution of Redox-sensitive Elements in Bottom Waters,Porewaters and Sediments of Rogoznica Lake (Croatia) in Both Oxic and Anoxic Conditions

Geochemical, mineralogical and sedimentological analyses were carried out to contrast two different sites (respectively characterized by permanently oxic and anoxic conditions) in a small, meromictic, seawater lake. In fact, due to relatively high organic matter content, and reduced water exchange, the Rogoznica Lake has almost permanent anoxic conditions below the depth of 12 m, where sediment can be considered an anoxic–sulphidic sedimentary environment. Different water column and sediments redox conditions affect the distribution and speciation of major redox-sensitive metals (Fe, Mn, Mo), reduced sulphur species (RSS) and dissolved organic C (DOC). Trace metals, especially those that accumulate in anoxic–sulphidic environments (Fe, Mo) showed a marked enrichment in the solid phase, whereas the low solubility of sulphides leads to low porewater concentrations. The relatively high sedimentary enrichment of Mo (up to 81 mg/kg) also confirms highly anoxic conditions within the Rogoznica Lake sediments. Results clearly show that chemical species within the sediments will tend towards equilibrium between porewater and solid phase according the prevailing environment conditions such as redox, pH, salinity, DOC.     

湖泊富营养化的灰色层次决策法综合评价

应用灰色统计决策、灰色局势效益和灰色聚类分析等多层次决策,对湖泊富营养化进行综合评价。研究表明,本法应用于18个湖泊富营养化的评价结果,与Fuzzy-Grey法评价结果一致。     

阳宗海砷浓度与浮游植物的变化分析

通过对2007--2011年阳宗海砷浓度和藻类数量、种类变化数据的研究,分析砷浓度对藻类的影响。     

太湖淤泥和自来水厂污泥混合制砖研究

以太湖淤泥和自来水厂污泥为原料进行烧结砖的制备研究,干原料经混合加湿搅拌,制成4 cm×4cm×4cm的砖体试样,干燥后放入马弗炉中焙烧;测试了砖坯的含水率、干燥收缩,烧结砖的烧失量、烧成收缩、表观密度、吸水率和抗压强度,并利用XRD和SEM分别测试了烧结砖的矿物成分,和微观形貌特征。研究结果表明,减少淤泥含量导致砖的密度和抗压强度降低,烧失量、烧成收缩率和吸水率上升;淤泥掺量减少到60%,成型含水率为23%,经950℃高温煅烧后,所得砖体质量较好,强度满足MU10等级。     

用杀藻剂抑制湖泊蓝藻水华的尝试

近 年来，各 种污染 导 致滇 池 水 体的 水 质呈 现 严 重的 富 营养 化 状 态， 蓝藻 泛 滥， 水 面 藻如 浮油。在一般 区 域 内， 藻 量 ５ ０００ ～７ ０００ 万 个／ Ｌ、叶 绿 素 － ａ ４００ ｍ ｇ／ ｍ ３ 、 Ｃ Ｏ Ｄ Ｃｒ１８ ｍ ｇ／ Ｌ、 Ｂ Ｏ Ｄ５１６ｍ ｇ／ Ｌ、透明 度３２ｃ ｍ 。在藻类 滋生的严 重的水域 ，藻量高 达１２ ０００ 万 个／ Ｌ， 水体 透明 度为 零。１９９８年５ 月至 ６ 月在云 南省昆明 市 滇池 外 海及 草海 ，采 用 Ｂ Ｃ ６５５ 杀藻 剂 进行 了现 场 杀藻 试 验。 试验结果表 明，在藻 类繁殖最 严重的区 域投加 杀藻 剂６ ｍ ｇ／ Ｌ 时杀 藻率 达７８ ％ 以 上； 投加 量 １５ ｍ ｇ／ Ｌ 时杀藻率 达９０ ％ 以上 ；用絮凝剂 除去部 分蓝藻后 ，只需投 加３ ｍ ｇ／ Ｌ，杀藻率即 可达到 ９９ ％ 以上     

GIS在B-IBI法评价鄱阳湖水生态系统健康性中的应用

在探讨目前国内外水生态系统评价方法的基础上,采用B-IBI法评价鄱阳湖水生态系统健康性,分析认为,底栖生物参数差异性与水体理化环境相关性不明显,提出将GIS与B-IBI法耦合使用进一步提高评价结果的精度,并以鄱阳湖为研究对象验证此法的精度,结果表明:GIS与B-IBI法耦合使用评价结果较好,误差在±10%范围内;鄱阳湖水生态系统总体处于亚健康-健康状态;长江口段及周溪镇段水生态系统较差,处于病态-亚健康状态,说明开展水生态修复工程迫在眉睫。评价结论对鄱阳湖管理部门制定水生态修复方案具有一定参考意义。     

瑶湖沉积物中磷的赋存形态及其空间分布特征

利用磷的分级提取分析方法,首先对瑶湖沉积物磷赋存形态进行了分析;其次将瑶湖分成A、B和C 3个区段(其营养状态指数TLI值的大小为:B区>A区>C区),在此基础上,探讨了铁结合态磷(Fe-P)、铝结合态磷(Al-P)、钙结合态磷(Ca-P)和有机磷(OP)的空间分布特征。研究结果表明:在沉积物磷赋存形态中,无机磷形态(IP)占总磷(TP)的平均比重为75%以上,Fe-P是IP的主要成分,Fe-P占TP比重范围为40.55%~67.63%;各种形态磷的平均含量(或占TP比重)大小为Fe-P >Al-P> OP>Ca-P >DP。Fe-P、Al-P和OP的水平分布特征的结果表明:对于相同的区段,不同磷赋存形态的含量变化具有相同的变化规律,其含量大小为Fe-P >Al-P >OP,而Ca-P含量变化相对稳定;对于不同的区段,相同磷的赋存形态含量的极值变化具有一定的差异,其中Fe-P、Al-P和OP的最大值均出现在B区段,而Fe-P和Al-P最小值出现在A区段,OP则出现在C区段。Fe-P、Al-P、Ca-P 和OP的垂直分布特征的结果显示:对于相同的区段,Fe-P、Al-P、Ca-P和OP的含量均随深度呈现递减趋势,当达到25 cm深度时其含量基本稳定;而对于不同的区段,Fe-P、Al-P和OP的含量随深度的变化趋势具有一定的差异性,A区段随深度的变化趋势比B区段和C区段缓慢,而Ca-P变化趋势则没有明显的区分,这一研究结果为揭示瑶湖富营养化发生的机制提供了数据和理论支撑。