赤潮的预测与控制对策

近年来,我国沿海地区越来越频繁的赤潮对水域环境与海水养殖业等造成了严重破坏。本文从赤潮发生的条件入手,分析了赤潮的预测方法,并提出了相应的对策。     

巴拉顿湖的污染控制

1988年9月我随四川省建委主任、省环保委员会副主任杜恒产参加了在匈牙利巴拉顿湖畔盖斯特里镇召开的第三届世界湖泊保护与管理大会。会议期间,考察了欧洲第_二大淡水湖——巴拉顿湖,听取了有关专家的报告。巴拉顿湖是一个大面积的浅水湖,面积596km~2,平均水深3.25m,容积1.9×10~9m~3,集水区面积5.179km~2。古往今来一直是匈牙利经济、文化的重要地区,是全国最重要的旅游、疗养地。60年代初对湖水监测的资料表明,4个湖区浮游植物的初级生产量几乎都处于中等营养状态。1973年在1号湖区测得单位面积的初级生产量竟是1963年     

利剑斩“黑龙”——溧阳市大力整治烟尘污染见成效

江苏省深阳市历时6个月的时间，投入治污资金逾600万元，整治炉（窑）294台，基本实现了市政府提出今年8月30日前解决市区“黑龙”污染的目标。这是漂阳市大力整治烟尘污染，1997为民办的环保实事之一。一、政府治污决心大初到保田的人，第一印象是“根根烟囱朝天，条条黑龙乱舞。”进入市区，总是一种迷雾股股的感觉。久居深城的人，更有一种说不出的困惑，因为在保城11．7平方公里的范围内有309台各类炉（窑），在年吃进约30万吨原煤的同时，向大气排放约1．5万吨烟尘、8400吨二氧化硫以及其他污染物。居民抱怨油烟、尘灰飞扬，被服无法晾…     

改善环境质量的重要经济手段

环境作为一种日益紧缺的资源是有价值的,任何污染都是对环境质量的损耗,理应付出相应的经济代价作为补偿。然而长期以来,由于缺乏商品经济观念和明确的国有产权意识,环境资源没有被作为一种特殊的和基本的经济要素来认真对待。十年经济体制改革,围绕着“搞活经济”这个中心推进,方向是对的,但同时也出现了国家宏观调控能     

汽车内空气污染情况调查分析

阐述汽车内空气污染的现状及原因,归纳总结了一些治理污染的方法,并且针对车内污染问题,提出了对策。     

西宁市大气环境污染现状及治理对策

依据１９９６－１９９８年青海省环境监测资料，分析了西安市大气环境污染状况及成因，并提出相应对策。     

燃煤引起的氟污染

氟是煤中的有害元素,煤燃烧时,煤中氟被释放出来。本文叙述了煤在燃烧过程中,氟化物形态的转化、释放氟的规律、氟在大气环境中的迁移、扩散机理,为氟污染的评价和防治提供科学依据。     

开展污染责任保险的意义及途径

污染责任保险在我国还处于试点阶段,本文结合大连市开展这项工作的实践,讲述了开展污染责任保险的意义和具体途径。     

我国机动车污染控制对策

防治汽车排气污染是城市环保工作的重要内容,是老百姓关注的热点和焦点。只有协调好汽车工业和环境的发展,大力发展高技术的清洁汽车,才能保持我国汽车工业可持续发展,实现在发展工业的同时,保护好我们赖以生存的环境。本文是在日前召开的“汽车排气催化净化技术产业化与发展战略研讨会”上对这一问题提出的有关对策。     

Provincial development plans in Zimbabwe: an analysis of their content,structure and methodology

Zimbabwean provincial plans were instituted to help in the achievement of the national goal of the creation of an egalitarian, socialist and integrated society. The national goal itself was adopted as an antithesis to the dualist society characterised by spatial, economic, social, politican and technological inequalities that Zimbabwe inherited from colonialism. This meant that provincial plans had to play both a functional (or growth allocating/distribution) and a territorial (or redistribution) role.

This paper reviews their role in achieving the national goal by examining their functions, content, structure and methodology. The paper concludes that because of their nature, provincial plans are not suitable tools for the achievement of the national goal.     

A DISTRIBUTED DYNAMIC WATERSHED MODEL1

ABSTRACT: A distributed watershed model was developed to mathematically simulate overland and channel flow for a single-event storm. The modeled watersheds in the study were subdivided into rectangular grid elements. All hydrologically significant parameters, such as land slope, rainfall and precipitation excess, were assumed to be uniform within each element. The Green-Ampt method was adopted to generate precipitation excess for each element during the simulation period. A two-dimensional diffusion wave model was used for overland flow routing and an iterative Alternative Direction Implicit scheme was used to solve the simultaneous overland flow equations. Once the overland flow became inflow to the channel, a one-dimensional dynamic wave flood routing technique, based on a four-point, implicit, non-linear finite difference solution of the St. Venant equation of unsteady flow, was applied. A limited number of comparisons were made between simulated and observed hydrographs for areas of about one square mile. Given the appropriate parameters, the model was able to accurately simulate runoff for single-event storms. This paper describes a distributed watershed model developed to simulate overland and channel flow. Comparisons were made between simulated and observed hydrographs for three watersheds. The model was able to accurately simulate the runoff for single-event storms using 61-m by 61-m (200 ft by 200 ft) watershed grid elements.     

Cadmium—Towards a rational use of a toxic element

Because of its toxicity, cadmium creates an environmental problem as well as a health hazard for exposed workers. Most cadmium emissions arise from the intentional use of the element. It is therefore mandatory to reduce cadmium consumption to the lowest possible level. Cadmium pigments, mainly used in plastic processing, can be replaced in all applications where the processing temperature does not exceed 300°C. Newly developed polyvinyl chloride stabilizers promise to be an excellent substitute for cadmium stabilizers in even the most demanding applications. Cadmium plating, still extensively used in the United States and the West Germany, has been virtually abandoned in Japan. Improved lead acid batteries are replacing vented nickel cadmium batteries because of their cost effectiveness. While in these applications cadmium use is declining, more and more cadmium is needed for the manufacturing of sealed nickel cadmium batteries. These relatively small electrochemical cells are used mainly by individual consumers. Here cadmium can only be replaced in some marginal applications. The high cadmium content of these batteries (up to 22%) makes them a good candidate for recycling of the heavy metal.     

The Effectiveness of Management Interventions Used to Control Ragwort Species

Ragwort (Senecio jacobaea and S. aquaticus) causes major losses to agricultural revenue and induces livestock morbidity throughout parts of Europe, North America, and Australasia. The introduction of legislation in the U.K. and Australia has meant that landowners can be prosecuted if the plant spreads to adjacent land, which has led to an increase in activities attempting to control these species. Commonly used interventions include natural enemies, herbicide applications, manual and mechanical removal. Through the use of explicit systematic methodology involving comprehensive searches and detailed inclusion criteria, data from primary research are collated for each type of intervention. Meta-analyses show that 2,4-D, Asulam, Clopyralid, and MCPA are effective at reducing ragwort densities. However, when the datasets were analysed for their effectiveness against individual species, 2,4-D and MCPA were only effective against S. jacobaea, while Asulam was only effective against S. aquaticus. Natural enemies Longitarsus jacobaeae and a combination of L. jacobaeae and Tyria jacobaeae appear to have the potential to reduce S. jacobaea densities. Only applying T. jacobaeae does not appear to significantly reduce S. jacobaea densities, but does reduce the number of capitula per plant, seeds per capitula, viability of seeds, and dry weight of the plants. There is insufficient experimental evidence available to assess other interventions such as manual or mechanical removal. Further research into these types of interventions is recommended, as well as more detailed reporting of site characteristics and experimental design to allow full investigation of each intervention to explain possible reasons for variations in their effectiveness.     

STATE VARIABLE MODEL FOR URBAN RAINFALL-RUNOFF PROCESS1

ABSTRACT: A nonlinear hydrologic system model has been developed for analyzing the urban rainfall-runoff process. The model is formulated as a state variable model consisting of several parameters. A search technique is employed to find the set of parameters for which the model's response best fits observed data. The model could be used in either a simulation or forecasting mode. The model is applied to observed data for the Waller Creek Watershed in Austin, Texas, to develop the model parameters for various levels of urbanization of the watershed. The trend of each parameter with respect to levels of urbanization is examined.     

Definition Procedures Have Little Effect on Performance of Environmental Classifications of Streams and Rivers

Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.     

Macroalgal Introductions by Hull Fouling on Recreational Vessels: Seaweeds and Sailors

Macroalgal invasions in coastal areas have been a growing concern during the past decade. The present study aimed to assess the role of hull fouling on recreational yachts as a vector for macroalgal introductions. Questionnaire and hull surveys were carried out in marinas in France and Spain. The questionnaires revealed that the majority of yacht owners are aware of seaweed introductions, usually undertake short range journeys, dry dock their boat at least once a year, and use antifouling paints. The hull survey showed that many in-service yachts were completely free of macroalgae. When present, fouling assemblages consisted mainly of one to two macroalgal species. The most commonly found species was the tolerant green seaweed Ulva flexuosa. Most of the other species found are also cosmopolitan and opportunistic. A few nonnative and potentially invasive Ceramiales (Rhodophyta) were found occasionally on in-service yachts. On the basis of the information gathered during interviews of yacht owners in the surveyed area, these occurrences are likely to be uncommon. However they can pose a significant risk of primary or secondary introductions of alien macroalgal species, especially in the light of the increase in yachting activities. With large numbers of recreational yachts and relatively rare occurrences of nonnative species on hulls, comprehensive screening programs do not seem justified or practical. The risks of transferring nonnative species may, however, be minimized by encouraging the behaviors that prevent fouling on hulls and by taking action against neglected boats before they can act as vectors.     

National minerals policies and stakeholder participation for broad-based development in the southern African development community (SADC)

This paper explains how the well-accepted concept of improved stakeholder participation during mineral policy development leads to a national mineral policy that accommodates the diverging views and interests that allows wide acceptance of decisions, enhancing the success of implementation and, ultimately, national benefits. This process is based on lessons learnt during the South African experience and has been successfully applied in the development of the Namibian and Malawian national minerals policies. An effective policy in the SADC will engineer the delicate balance between poverty reduction and an internationally competitive minerals sector. This balance enhances the possibility of long-term economic growth and development in the SADC region. The overriding advantage of this strategy is that it generates ‘home-grown’ policy instruments and implementation of mineral law with which stakeholders can identify. This process presents a new challenge to traditional policy formulation strategies in emerging economies and the bottom-up approach, linked to wide political support, allows the potential realisation of national objectives.     

Prymnesium parvum Control Treatments For Fish Hatcheries1

Barkoh, Aaron, Dennis G. Smith, and Gregory M. Southard, 2010. Prymnesium parvum Control Treatments for Fish Hatcheries. Journal of the American Water Resources Association (JAWRA) 46(1):161-169. DOI: 10.1111/j.1752-1688.2009.00400.x Abstract: In 2001, the ichthyotoxic microalga Prymnesium parvum caused massive fish kills and adversely affected fish production at the Texas Parks and Wildlife Department (TPWD) Dundee State Fish Hatchery. Since then, we have investigated several P. parvum bloom and ichthyotoxicity control treatments to develop management strategies that allow fish production and prevent the spread of the alga into unaffected hatcheries and impoundments. Current control successes include treatments for ponds, water supply, and a hazard analysis and critical control point program. For pond treatment, ammonium sulfate (as 0.14-0.25 mg/l un-ionized ammonia nitrogen for temperatures above 15°C), copper sulfate (2 mg/l), Cutrine^®-Plus (0.2-0.4 mg/l as copper), or potassium permanganate (3 mg/l above the potassium permanganate demand) controls P. parvum blooms. Copper sulfate at 1 mg/l controls P. parvum but is unable to eliminate ichthyotoxicity whereas potassium permanganate at 2 mg/l above the potassium permanganate demand controls ichthyotoxicity. For water treatment, ultraviolet (UV) light at 193-220 mJ/cm² doses or ozone at 0.4-1.2 mg/l for 6 min destroy P. parvum cells and reduce or eliminate ichthyotoxicity. A combination UV and ozone treatment appears to provide the best results; however, successful treatments depend on dosage relative to cell density and toxin concentration. To prevent the spread of the alga, hatchery fish delivery units and equipment are cleaned with household bleach (10% solution for 15 minutes) or hydrogen peroxide (62.5-12,500 mg/l for 0.25-24 hours). These treatments are tailored to water quality conditions and the fish species cultured at affected TPWD hatcheries. We recommend that other users test these treatments before applying them to ponds or other impoundments containing fish or other aquatic life.