A Chemical Characterization of A Lagoon Ecosystem: The Sacca Di Goro (Po River Delta, Italy)

This work reports on the results of a preliminary estimate of the presence and distribution of common and rare elements in a typical estuarine environment of the Po River Delta. Different environmental compartments (sediment, water, macroalgae and benthic animals) were considered, and analysis conducted on samples taken at two different sites characterized by low and high hydrodynamic regime. Resulting evidence of differences between the matrices, especially in relation to their different nature and sampling site are given.     

Gas and Organic Matter in Last Glacial and Holocenic Sediments of Venice Lagoon

Two drills (MBM1* and MBM2) provided at “Bocca di Malamocco” gave environmental and palaeo-environmental information on sedimentation for the last 50,000 years. the MBM2 supplies textural, gas and organic matter studies of sediment and principal ion content of pore water. Two main palaeo-environments, divided in six cycles, are recognized. Marine environment characterizes the sediment above 12.80 metres below sea level (mbsl) and continental environment dominates the sediments below.

The concentration/depth profiles of dissolved ammonia, phosphates and gases are related to the occurrence of a relatively high organic content in the sediment core. Carbon dioxide to methane ratio shows a constant value below 20 mbsl, while above that level only carbon dioxide was detected. A sulphate gradient in the transition zone between the marine to fresh water interval suggests a methane oxidation. These findings indicate that diffusive transport of methane from marine sediments to the atmosphere may be considered minimal. the sedimentary cycles are related to the oxygen isotopic stages. They suggest a variable hydraulic regime occurred during the last Glacial time in the palaeo-plain corresponding to the present Venice lagoon.     

清淤疏浚工程对七里海潟湖湿地水体交换的影响

七里海潟湖湿地受到人类活动的影响,湖盆淤积、湖面萎缩、水质恶化,其生态修复工程（一期）通过对湖盆进行清淤疏浚来改善潟湖生态环境.基于三重嵌套非结构网格建立七里海潟湖湿地水动力和物质输运数学模型,采用实测资料对模型的潮位、流速和流向进行验证,运用欧拉法计算潟湖整体滞留时间及其空间分布,分析工程对七里海潟湖水动力和水体交换的影响,结果表明：（1）工程对潮位的影响较小,工程后潮汐通道口门处涨落潮流量增大,涨落潮流速也随之增加;（2）工程后,潟湖纳潮量较工程前提升87%,滞留时间较工程前降低38%,水体交换能力自潮汐通道向潟湖内部逐渐减弱,工程对潟湖水体交换能力的改善主要集中在河道及潟湖中心水域;（3）工程前水体滞留时间的分布主要受到潟湖地貌影响,工程后水深增大,流场受地貌的影响变小,水体交换能力的分布主要受到潟湖流场影响.清淤疏浚工程有助于潟湖改善水体的交换能力和生态环境.     

高压喷射注浆加固地基RJP工法及北京现场试验

为满足土木工程建设对大直径旋喷桩和超深基础防漏止水的需要，１９８８年ＲＪＰ（ＲｏｄｉｎＪｅｔＰｉｌｅ）工法应运而生。其旋喷桩直径达２４０～３２０厘米，固结体质量优良，工艺可靠，成本较低。１９９６年５月在旋喷发明人、本工法专利权拥有者中西涉博士的指导下，中日数公司在北京探矿机械厂内联合进行了ＲＪＰ工法现场试验。旋喷桩直径达３米，团结强度良好，施工工艺简单。试验结果表明，在拥有三重管旋喷设备和经验的中国有良好的推广应用价值和发展前景。     

探讨垃圾填埋场开采回用工程

介绍了垃圾填埋场开采回用的目的、稳定化条件和开采工艺,并结合盐田垃圾场清场处置工程实例,探讨了开采工艺中斜面分层作业和垃圾造堆工艺,得出结论:斜面分层作业和垃圾造堆,可以大大降低垃圾的密度,提高松散度,更有利于保障开挖作业安全。     

稳定塘中枝角类的生物指示作用

经实验观察发现,在多级稳定塘的各个级别中,由于水质的差异、枝角类的数量、颜色、个体大小三特性发生规律性变化,所以,可利用枝角类这些特性变化确定稳定塘污水净化的程度。     

Electrocoagulation coupled with electrooxidation for the simultaneous treatment of multiple pollutants in contaminated sediments

In situ and simultaneous remediation of a variety of pollutants in sediments remains a challenge. In this study, we report that the combination of electrocoagulation (EC) and electrooxidation (EO) is efficient in the immobilization of phosphorus and heavy metals and in the oxidation of ammonium and toxic organic matter. The integrated mixed metal oxide (MMO)/Fe anode system allowed the facile removal of ammonium and phosphorus in the overlying water (99% of 10 mg/L NH₄⁺-N and 95% of 10 mg/L P disappeared in 15 and 30 min, respectively). Compared with the controls of the single Fe anode and single MMO anode systems, the dual MMO/Fe anode system significantly improved the removal of phenanthrene and promoted the transition of Pb and Cu from the mobile species to the immobile species. The concentrations of Pb and Cu in the toxicity characteristic leaching procedure extracts were reduced by 99% and 97% after an 8 hr operation. Further tests with four real polluted samples indicated that substantial proportions of acid-soluble fraction Pb and Cu were reduced (30%–31% for Pb and 16%–23% for Cu), and the amounts of total organic carbon and NH₄⁺-N decreased by 56%–71% and 32%–63%, respectively. It was proposed that the in situ electrogenerated Fe(II) at the Fe anode and the active oxygen/chlorine species at the MMO anode are conducive to outstanding performance in the co-treatment of multiple pollutants. The results suggest that the EC/EO method is a powerful technology for the in situ remediation of sediments contaminated with different pollutants.     

Seasonal Fluctuations in the Nutritional Value of Particulate Organic Matter in A Lagoon

Water samples were collected on a fortnightly basis in the lagoon of S. Gilla (Sardinia, Mediterranean Sea) in order to study seasonal nutritional fluctuations of particulate organic matter. the lagoon is characterized by high quantities of suspended matter throughout the year. Thermohaline conditions had no effect on particulate matter quantity and composition, but the quantity as well as quality of suspended particles was drastically affected by the wind, the major effecter of sediment resuspension. As a result of sediment resuspension, seston was always richer in inorganic fraction. However, throughout the year of investigation, most particulate organic carbon was quite appealing for filter feeding communities, although the best POM quality was available during phytoplankton blooming. the phytoplankton pool of suspended matter was just a small fraction of the bulk, accounting for only 13% on average of particulate organic carbon. in terms of energy available in the seston, the highest amount was stored in organic matter heterotrophic fraction, whilst the smallest was to be found in living phytoplankton.     

宁波市某人工泻湖浮游生物变化特征及影响因素分析

以宁波市北仑区梅山水道形成的人工泻湖为研究对象,在不同季节进行水质及浮游生物调查,分析其浮游生物时空分布特征与水质的关系。4个采样点共检出浮游植物66种,以硅藻为绝对优势种,检出浮游动物25种,主要为桡足类、少量轮虫及网纹虫;拦坝后水道内浮游生物密度有了数量级增长,各项生物评价指数降低,但各采样点仍处于中污染水平。监测理化参数表明,研究水域在拦坝后盐度下降、悬浮物浓度下降,氮磷含量无明显变化;水域大部分点位处于中度富营养化水平。结合浮游生物分布与理化参数进行分析,发现堤坝合龙后,水道内侧海水淡化、悬浮物含量下降,导致浮游生物密度上升、生物多样性下降、出现淡水优势种群;营养盐含量不是浮游生物生长的限制因子,对浮游生物分布无显著影响。     

Stabilization-based soil remediation should consider long-term challenges

Soil remediation is of increasing importance globally, especially in developing countries. Among available remediation options, stabilization, which aims to immobilize contaminants within soil, has considerable advantages, including that it is cost-effective, versatile, sustainable, rapid, and often results in less secondary pollution. However, there are emerging challenges regarding the long-term performance of the technology, which may be affected by a range of environmental factors. These challenges stem from a research gap regarding the development of accurate, quantitative laboratory simulations of long-term conditions, whereby laboratory accelerated aging methods could be normalized to real field conditions. Therefore, field trials coupled with long-term monitoring are critical to further verify conditions under which stabilization is effective. Sustainability is also an important factor affecting the long-term stability of site remediation. It is hence important to consider these challenges to develop an optimized application of stabilization technology in soil remediation.