Organochlorines in the surface sediments of the Bahiret el Bibane lagoon (Tunisia,Southwestern Mediterranean Sea)

Organochlorines (including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs)) were analysed in 10 surface sediment samples collected from the Bahiret el Bibane lagoon, which is one of the most productive lagoons and one of the most important active commercial fish traps in the southern Tunisia. The aim was to obtain information concerning the recent deposition of these compounds in this area, together with the levels, the distribution and any potential biological risk. Total concentrations of OCPs and PCBs in the sediments ranged from below the limit of detection (?1 and from 29.5 to 88.2?ng?g^?1?dw, respectively. The spatial distribution of PCBs suggested that the sources of these contaminants are probably located outside the lagoon and are transported by water currents and atmospheric deposition. Compared with some other regions of the world, the Bahiret el Bibane lagoon exhibited low to moderate levels of PCBs and OCPs. According to established sediment quality guidelines, PCBs and Lindane at most of the study sites would be more concerned for the ecotoxicological risk in the Bahiret el Bibane lagoon. The results of this study could provide a useful aid for the sustainable marine management of the region.     

污泥中重金属性质分析及处理方法实验研究

选取典型城市污水厂污泥进行重金属总量及形态分析，确定超标重金属的含量、形态，并选择重金属稳定化方法对污泥中的重金属进行了初步实验。通过实验，结果证明了重金属的稳定化是污泥农用中重金属控制的有效方法，并给出了进一步研究的目标和建议。     

10万m3/d污水处理厂新型稳定塘工艺技术经济分析

介绍了沙营污水处理厂稳定塘工艺的构成特点及2年来实际运行效果。效益分析表明,新型稳定塘工艺通过在厌氧塘安装弹性填料、在好氧塘增加表面曝气机,在养鱼塘放养各类鱼苗、在生态塘种植莲藕、芦苇,从而形成了人工可以控制的生物氧化过程来处理城市污水,具有基建投资省、维护管理方便、运行费用低等特点,在土地资源丰富的中小城市具有良好的应用前景。     

An Ecological and Economic Assessment Methodology for Coastal Ecosystem Management

An adaptation of the Drivers-Pressure-State-Impact-Response methodology is presented in this work. The differential DPSIR (ΔDPSIR) was developed to evaluate impacts on the coastal environment and as a tool for integrated ecosystem management. The aim of the ΔDPSIR is to provide scientifically-based information required by managers and decision-makers to evaluate previously adopted policies, as well as future response scenarios. The innovation of the present approach is to provide an explicit link between ecological and economic information related to the use and management of a coastal ecosystem within a specific timeframe. The application of ΔDPSIR is illustrated through an analysis of developments in a Southwest European coastal lagoon between 1985 and 1995. The value of economic activities dependent on the lagoon suffered a significant reduction (ca. −60%) over that period, mainly due to a decrease in bivalve production. During that decade the pressures from the catchment area were managed (ca. 176 million Euros), mainly through the building of waste water treatment plants. Notwithstanding this, the ecosystem state worsened with respect to abnormal clam mortalities due to a parasite infection and to benthic eutrophication symptoms in specific problematic areas. The negative economic impacts during the decade were estimated between −565 and −315 million Euros, of which 9–49% represent the cost of environmental externalities. Evaluation of these past events indicates that future management actions should focus on reducing the limitation on local clam seeds, which should result in positive impacts to both the local socio-economy and biodiversity.     

Anthropogenic influences on a mediterranean Nature Reserve: modelling and forecasting

The lagoon of Biguglia (northeastern Corsica) is one of a number Nature Reserve. Anthropogenic activities are increasing over its watershed however. The present study aims to examine the state of health of the lagoon with the example of two pollutants (Cd and Cu). Water samples were collected in spring and summer 1997. The trace metal fluxes between the various compartments were measured. Transfer processes from the watershed to the lagoon were also examined. The temporal evolution of Cd and Cu content is assessed on the one hand by comparing the present data with former reference work (1992). On the other hand, a 5-box model is implemented in order to reduce the complex functioning of the lagoon to a system of differential equations. With the help of a numerical resolution method, the increase of metallic concentration levels is estimated since 1992. On the basis of 1997 data, two hypotheses are compared. The hypothesis that takes into account a growing increase of anthropogenic activities on the watershed gives, by extrapolation, results that are closer to field measurements. However, even with this hypothesis, the cadmium content in the lagoon is underestimated. This may signify that for this metal the evolution of the lagoon pollution is more important than a linear increase.     

新村港海草床生态系统健康评价

通过分析2004—2009年海南岛新村港海草床生态系统的水环境、沉积环境、生物残毒、栖息地、生物等5类18项评价指标的调查数据,并根据《近岸海洋生态健康评价指南》(HYT 087—2005)的评价标准,对新村港海草床生态系统的健康状况进行评价。结果显示,新村港水质、沉积环境、生物残毒和栖息地等4个评价指标的健康状况为健康,健康指数分别为11.4、9.0、7.1、13.0,水环境健康指数临近亚健康临界值;生物评价指标的健康状况为亚健康,健康指数为30.0;综合以上5类指标评价,新村港海草床生态系统的健康状况为亚健康,健康指数为70.5。海水养殖、污水排放、海洋工程、渔业活动等是导致海草床退化、底栖生物减少、水环境质量下降的主要原因。     

Heavy metal and nutrient changes during vermicomposting animal manure spiked with mushroom residues

A pilot-scale trial of four months was conducted to investigate the responses of heavy metal and nutrient to composting animal manure spiked with mushroom residues with and without earthworms. Results showed that earthworm activities accelerated organic matter mineralization (e.g. reduction in C/N ratio, increase in total concentrations of N, P, K) and humification (e.g. increase in humic acid concentration, humification ratio and humification index). Despite composting increased total heavy metal (i.e. As, Pb, Cu, Zn) concentrations irrespective of earthworm, the availability of heavy metals extracted by DTPA significantly (P < 0.05) decreased particularly in treatments with earthworms introduced. The shift from available to unavailable fractions of heavy metals was either due to earthworm bioaccumulation, as indicated by total heavy metal concentrations being higher in earthworm tissues, or due to the formation of stable metal-humus complexes as indicated by the promotion of humification. Our results suggest that vermicomposting process could magnify the nutrient quality but relieve the heavy metals risk of agricultural organic wastes.     

Bioaccumulation of Some Heavy Metals in Different Tissues Of Dicentrarchus Labrax L, 1758, Sparus Aurata L, 1758 And Mugil Cephalus L, 1758 From the ÇamlIk Lagoon of the Eastern Cost Of Mediterranean (Turkey)

In this study, bioaccumulation of the heavy metals (Fe, Zn, Cd) in the liver, gill, gonad and muscle tissues of Dicentrarchus labrax, Mugil cephalus and Sparus aurata were investigated seasonally. Camlik is the important fisheries lagoon located in The Iskenderun Bay, Mediterranean coast of Turkey. Due to heavy industrial and agricultural activities in the region, the bay has the polluted coastal waters of Turkey. Therefore, the levels of cadmium, zinc, iron were determined in the muscle in each species because of its importance for human consumption and also the liver, gill, gonad were analysed since these organs tend to accumulate metals. Heavy metal levels were found generally higher in the liver and gill than the gonad and muscle tissues in three species; the levels of all metals in a given tissue were generally higher in Mugil cephalus than the other two species. Data collected in this study suggest that Camlik lagoon is affected by a relatively metal pollution. The concentrations of Zn concentrations in the muscle tissues exceeded the acceptable levels for a food source for human consumption and other metals in the edible parts of the investigated fish were in the permissible safety levels for human uses.     

Water quality assessment through hydrodynamics and transport simulation in the S. Gilla lagoon, Italy

The paper describes the study of the hydrodynamic and transport features of the S. Gilla lagoon in Sardinia, Italy. The study, aimed at assessing the environmental quality of the water body, involved extensive use of numerical models based on the shallow water equations, thus enabling to simulate a number of different situations of practical interest. Based on field data, six meteorological and hydrologic patterns were recognised which were assumed as representative of the various conditions occurring in the four seasons. Typical winter conditions proved effective for the water refreshment, while the other seasonal patterns induced a stronger internal mixing. Thus, unfavourable salinity distributions with respect to the fish farm activities, which are carried out in the water body, were obtained with the winter pattern, whereas, on the other hand, a higher dilution of pollutants discharged by the river inflows was achieved. In general, between dominant winds, southeast winds proved more effective in forcing internal mixing than northwest winds. Two flood events with quite different return periods were also simulated, in order to estimate the extent of the inundated areas and the salinity depletion. The consequent salinity recovery was simulated both in natural conditions and with the discharge of salt sea water into the lagoon to accelerate the salinity re‐equilibrium. This revised version was published online in August 2006 with corrections to the Cover Date.     

World copper market, 1973–1982, and international stabilization policies

This article critically examines international price stabilization policy in relation to the main features of the world copper market and the structural changes that have affected the industry in the decade up to 1982. The first section summarizes the main features of the world copper market, briefly discussing the principal structural changes; the second part examines the recent pattern of investment in copper and changes in ownership of some copper producing companies resulting from the need for improved cash flows due to the adverse effects of the recession; and the third part analyses the practical and theoretical issues relating to the question of price instability. A number of formidable problems are likely to arise from such price stabilization policies and it is concluded that it is because of these difficulties that the policies have not been implemented. Consequently, international commodity agreements designed to minimize or avoid price instability have proved difficult to conclude. New questions on which consensus is likely should be examined to promote intergovernmental co-operation, and hence market stability. With that end in view, this article lists some new questions that could form the basis of an agenda for exploratory intergovernmental discussions on copper.