Biological benthic tools as indicators of coastal marine ecosystems health

Coastal marine ecosystems are increasingly subjected to environmental stress and degradation due to pollution. Several research programmes have addressed this problem and produced relevant data sets for specific areas, often including consistent sets of environmental and biological variables. The value of existing information gathered from these types of data can be largely increased by combining them into a common data set to determine globally applicable relationships. To perform this exercise, the Intergovernmental Oceanographic Commission (IOC) of UNESCO has recently formed the Ad hoc Study Group on Benthic Indicators (http://www.ioc.unesco.org/benthicindicators) with the aim of developing robust indicators of benthic health. In this paper, initial products and ongoing activities of this international initiative are described and discussed. An expansion of initial IOC/UNESCO research on benthic fauna-organic carbon relationships is also presented. As part of this follow-up research, the relationship between total organic carbon concentrations of sediment and abundance, biomass and species diversity of benthic macrofauna was evaluated using data sets from 2 different regions of the world comprising 3 different coastal marine environments. The ability of identifying threshold levels in selected variables that could serve as indicators of related adverse environmental conditions leading to stress in the benthos is envisaged within the frame of a larger joint analysis, carried out by the IOC/UNESCO Study Group on Benthic Indicators, of merged data sets from several coastal regions worldwide.     

电解反应器电极排列方式研究

提高电极表面反应物扩散速率以及提高反应器效率是强化电解反应器处理能力、降低电耗的重要途径,安装中心推进式搅拌叶轮、辅射状电极的新型电解反应器可达到这2个目的.数学推导证明,新型电解反应器与同心圆状电极电解反应器效率比大于2.利用研制的反应器效率为9.9 m2/m3的新型电解槽,完成了电镀工业高质量浓度含氰废水处理的工业试验,废水氰化物平均质量浓度为17 000 mg/L,平均电解时间为17.7 h,氰化物去除率为99.6%,处理每kg CN-耗电15.1 kW·h.2年多的工业应用表明,带中心推进式搅拌叶轮的辐射状电极电解槽,具有操作容易、氰化物去除率高、回收金属方便、处理成本低等优点,其性能优于常规的同心圆状电极电解槽.      

丙烯腈生产废水的组成对膜吸收去除氰化物的影响

以吉林某石化公司的实际丙烯腈生产废水为研究对象,考察了丙烯腈生产废水的组成对膜吸收去除氰化物的影响. 结果表明:丙烯腈生产废水中的氰化物基本为易释放的氰化物,共存的挥发性丙烯腈对膜吸收法去除氰化物的影响可以忽略不计;废水中的丙酮氰醇对膜吸收法去除氰化物的影响最大. 丙烯腈废水采用膜吸收除氨-除氰工艺,由于碱性环境以及适当的加热,促进了丙酮氰醇分解转化为HCN,氰化物的去除率可以从40%～70%提高到82%～90%,同时氨氮的去除率达到93.3%以上. 气态膜吸收法能够有效去除并回收丙烯腈废水中的氨氮和氰化物,有效降低后续处理负荷,并为后续生物处理提供可能的条件.      

Economics of harvesting age-structured fish populations

A generic age-structured model is developed to derive analytical results on optimal harvesting. Given two age classes, knife-edge selectivity, and no stock-dependent harvesting cost, the steady state is a unique saddle point. Adding harvesting cost does not alter the uniqueness, given that the utility is linear. Under specific conditions such as nonselective gear, optimal harvesting is proved to be a stationary cycle that represents pulse fishing. Optimal steady states are different if age-structured information is ignored and optimization is based on traditional biomass variables. This implies that the existence of optimal sustainable harvesting depends on age-structured information. Given a specific set of conditions such as low interest rate and knife-edge selectivity, optimal harvesting converges toward a unique saddle point independently of the number of age classes.     

Economic Valuation of a Mangrove Ecosystem Threatened by Shrimp Aquaculture in Sri Lanka

Mangrove ecosystems in Sri Lanka are increasingly under threat from development projects, especially aquaculture. An economic assessment is presented for a relatively large (42 ha) shrimp culture development proposed for the Rekawa Lagoon system in the south of Sri Lanka, which involved an extended cost–benefit analysis of the proposal and an estimate of the “total economic value” (TEV) of a mangrove ecosystem. The analysis revealed that the internal benefits of developing the shrimp farm are higher than the internal costs in the ratio of 1.5:1. However, when the wider environmental impacts are more comprehensively evaluated, the external benefits are much lower than the external costs in a ratio that ranges between 1:6 and 1:11. In areas like Rekawa, where agriculture and fisheries are widely practiced at subsistence levels, shrimp aquaculture developments have disproportionately large impacts on traditional livelihoods and social welfare. Thus, although the analysis retains considerable uncertainties, more explicit costing of the environmental services provided by mangrove ecosystems demonstrates that low intensity, but sustainable, harvesting has far greater long-term value to local stakeholders and the wider community than large shrimp aquaculture developments.     

An Innovative Index for Evaluating Water Quality in Streams

A water quality index expressed as a single number is developed to describe overall water quality conditions using multiple water quality variables. The index consists of water quality variables: dissolved oxygen, specific conductivity, turbidity, total phosphorus, and fecal coliform. The objectives of this study were to describe the preexisting indices and to define a new water quality index that has advantages over these indices. The new index was applied to the Big Lost River Watershed in Idaho, and the results gave a quantitative picture for the water quality situation. If the new water quality index for the impaired water is less than a certain number, remediation—likely in the form of total maximum daily loads or changing the management practices—may be needed. The index can be used to assess water quality for general beneficial uses. Nevertheless, the index cannot be used in making regulatory decisions, indicate water quality for specific beneficial uses, or indicate contamination from trace metals, organic contaminants, and toxic substances.     

Routine, automated determination of inorganic and total mercury in multimedia using cold vapour atomic absorption spectrometry

A routine, automated analytical method for simultaneous determination of total and inorganic mercury by cold vapour atomic absorption spectrometry in multimedia is described. Excellent accuracy and precision results were obtained with human hair certified reference materials namely, BCR-397 and IAEA-086. The reproducibility relative standard deviation for total mercury was 4% and 22%, respectively. The limit of detection for total and inorganic mercury was 0.2 μg/g hair. The described method has been successfully applied in determination of total and inorganic mercury as well as organic mercury in human hair, urine and fish tissue samples.     

紫外分光光度法测定总氮空白值过高原因分析

碱性过硫酸钾消解紫外分光光度法测定总氮过程中,常常发生空白值过高而影响测定的情况,可能造成空白值过高的原因很多．主要包括纯水质量、试剂纯度、实验条件等几个方面,通过对可能造成总氮测定空白值过高的各项原因进行逐一系统分析和试验．发现造成空白值过高的原因主要为试剂过硫酸钾纯度不够,含有的总氮杂质过高所致,采用二次重结晶的方法时过硫酸钾试剂提纯后使用。同时严格地按照标准方法要求控制实验条件,即可大大降低总氮测定的空白值。     

胶州湾入海污染物目标总量控制研究

根据对胶州湾水质的实际调查结果,确定DIN,COD为胶州湾的主要污染因子。对胶州湾陆源污染物现状入海量进行调查,并以2008年为基准年,以COD,NH3-N为预测因子,预测2010年胶州湾各排污单元污染物增加情况。提出基于现实、分阶段实行目标总量控制的总量分配原则,根据国家和山东省给青岛市下达的总量控制指标和2008年青岛主要污染物实际排放情况,确定2010年胶州湾COD排放总量控制目标为34675t,NH3-N入海通量总量控制目标为6943t,并对各排污单元的排放总量控制目标值进行了分配。     

流域容量总量分配及排污交易潜力分析

流域容量总量的公平分配方法和排污交易潜力分析是目前流域管理研究的热点.采用层次分析法(AHP)和基尼系数交互反馈的方法研究了基于人口和经济公平的流域容量总量分配方案,并在此基础上建立了不考虑交易成本时的流域排污交易优化模型.将该模型用于分析邛海流域TP交易,得到污染控制总成本最小时的TP削减工程方案和排污交易方案.通过对比交易和未交易时的污染治理最小总成本发现,在不考虑交易成本时,排污交易有节约22.35%总成本的潜力.由于未考虑交易成本,这并不能说明邛海流域排污交易是可行的.但通过这种方法可以确定邛海流域排污交易可行的最大交易成本为1.56×109元·a-1.为了增大排污交易的可行性,应减少信息收集、谈判、管理、监测等方面的交易成本使其低于这一阈值.提出的排污交易优化模型能够提供交易信息,具有降低交易成本的潜力.