Volatilization of mercury from natural water by a broad-spectrum Hg-resistantBacillus pasteurii strain DR2

Summary A broad-spectrum mercury-resistant bacterial strain was isolated from contaminated water and was identified as Bacillus pasteurii strain DR2. It could volatilize Hg-compounds including organomercurials from its growth media. It utilized several aromatic compounds as a sole source of carbon. The bacterial strain eliminated HgCl₂ from sterile river water and the presence of benzene, toluene, naphthalene and nitrobenzene at 1 mM concentration in the system increased the rate of mercury volatilization, the volatilization rate being highest with benzene. When 1.7×10⁷ cells of this bacterial strain were added per ml of non-sterile water the bacterial strain volatilized more than 90 percent of mercury from mercuric chloride and organo-mercurials like PMA, thiomersol and methoxy ethyl mercuric chloride (MEMC). In the absence of this bacterial strain the volatilization of PMA and MEMC due to the presence of other Hg-resistant organisms in nonsterile polluted water ranged between 20–25 percent and of HgCl₂ was about 40 percent. However, in the presence of B. pasteurii DR2 volatilization of these Hg-compounds from non-sterile water increased by 20–40 percent. In the presence of 1 mM benzene the rate of mercury volatilization was even higher. In all the cases the rate of volatilization was higher in the first seven days than in the next seven days.Professor A. Mandal, MSc, PhD is Head of the Department of Biochemistry at the University College of Science, 35 Ballygunge Circular Road, Calcutta 700019, to whom correspondence should be addressed. His co-workers are Dr K. Pahan, Postdoctoral Associate, Department of Cell Biology and Paediatrics, Medical University of South Carolina, USA; Dr J. Chaudhuri, Senior Lecturer, Department of Molecular Biology, BKC College, Calcutta, India; Dr D.K. Ghosh, Postdoctoral Associate, Department of Biochemistry, University College of Science, Calcutta, India; Dr R. Gachhui, Postdoctoral Associate, The Cleveland Clinic Foundation, Cleveland, USA; and Dr S. Ray, Postdoctoral Associate, The Johns Hopkins University School of Hygiene and Public Health, Department of Biochemistry, Baltimore, USA.     

The environmental impact of Chernobyl in the soviet union

Summary The author describes events subsequent to the Chernobyl nuclear reactor accident and something of their environmental impact as it affects the Soviet Union. He is somewhat adversely critical of the lack of information currently being released by the Soviet authorities.Dr Zhores Medvedev was born in Tbilisi, and trained firstly as a plant biochemist and subsequently as a molecular biologist in the USSR. He studied the ecological effects of the 1958 Kyshtym nuclear accident in the USSR and published his findings in a bookNuclear Disaster in the Urals in 1979. He is currently a research scientist at the National Institute of Medical Research in London. A comprehensive analysis ofSoviet Agriculture is about to appear in a book of that title under Dr. Medvedev's authorship.     

The biodiversity challenge: Expanded hot-spots analysis

Summary This paper aims to throw light on the mass extinction that is overtaking Earth's species. Using an analytic methodology developed for an earlier partial assessment, it focuses on a series of hot-spot areas, these being areas that (a) feature exceptional concentrations of species with high levels of endemism, and (b) face exceptional threats of destruction. The paper identifies another eight such areas, four of them in tropical forests and four in Mediterranean-type zones. The analysis reveals that the four tropical-forest areas contain at least 2,835 endemic plant species in 18,700 km², or 1.1 percent of Earth's plant species in 0.013 percent of Earth's land surface; and that the four Mediterranean-type areas contain 12,720 endemic plan: species in 435,700 km², or 5.1 percent of Earth's plant species in 0.3 percent of the Earth's land surface. Taken together, these eight hot-spot areas contain 15,555 endemic plant species in 454,400 km², or 6.2 percent of Earth's plant species in 0.3 percent of Earth's land surface. This is to be compared with the earlier hot-spots analysis of 10 tropical-forest areas, with 34,400 endemic plant species in 292,000 km², or 13.8 percent of Earth's plant species in 0.2 percent of Earth's land surface.Taking all 18 hot-spot areas together, we find they support 49,955 endemic plant species, or 20 percent of Earth's plant species, in 746,400 km², or 0.5 percent of Earth's land surface. This means that one fifth of Earth's plant species are confined to half of one percent of the Earth's land surface — and they occur in habitats that are mostly threatened with imminent destruction.By concentrating on these hot-spot areas where needs are greatest and where the pay-off from safeguard measures would be greatest, conservationists can engage in a more systematised response to the challenge of large scale impending extinctions.Dr Norman Myers is a consultant in environment and development, a member of this journal's Advisory Board, and a regular contributor to the journal. He is a Senior Fellow of World Wildlife Fund — US. This paper enlarges on an important theme developed by Dr Myers in a contribution which appeared inThe Environmentalist,8(3), 187–208. The research for this paper has been supported by the MacArthur Foundation, Chicago, USA.     

Towards global climate change mitigation: assessment of an afforestation option for Nigeria

This paper assesses the potential of an intensive afforestation program as a measure of reducing the atmospheric concentration of carbon in Nigeria. The results presented are based on the recently completed Nigerian Country Studies Program on Climate Change Mitigation. A comprehensive mitigation analysis process (COMAP) model was employed to carry out detailed cost/benefit evaluation of the mitigation option. The end-use based scenario adopted was considered the most appropriate strategy to sustainably implement the mitigation option in Nigeria.The analyses showed that the country could significantly reduce net carbon emission while at the same time meet all her essential domestic wood needs, if approximately 7.5×10⁶ ha of wasteland could be committed to an afforestation program over the 40 year period of projection. The initial cost of establishing such forest plantations, taking cognisance of the opportunity cost of land averaged at about US$500/ha, or in carbon terms, a unit cost of about $13 per tonne of carbon. In terms of carbon flow, if all the end-product based plantations considered (i.e. fuelwood, poles, pulpwood, sawlogs and veneer) were fully established and maintained, it was estimated that by the year 2030, the total carbon stored in the afforested land would be about 638.0×10⁶ t of carbon with an annual incremental rate of 16.0×10⁶ t of carbon. Other economic indicators (i.e. net present value of benefits, present value of costs and benefit for reduced atmospheric carbon) when evaluated showed that the afforestation option could be economically viable even when the investment capital was discounted at rates ranging from 9 to 33 percent for different wood products. It should be noted, however that implementation of such a program would require huge sums of money and a high degree of commitment on the part of Federal, State and Local governments if the associated financial, social and environmental benefits were to be derived.     

Causes and effects of siltation on the environment of Nepal

Summary The present investigation was carried out in 1986, and is based upon about 20 years of river discharge data (1960s to 1980s). There are three important river-systems in Nepal - Sapt Kosi River system in East Nepal, Sapt Gandaki River system in mid- Nepal, and Karnali River system in West Nepal. The average annual highest rainfall is 3,685 mm yr^–1, and the greatest mean annual suspended sediment load (1.434 g L^–1) was recorded in Sapt Gandaki, while the water discharge from Sapt Kosi (1,747 m³ s^–1) was the highest and so also was the silt discharge (0.4 million ton day^–1). The correlation between water discharge and silt discharge was found to be statistically highly significant as verified by correlation and regression analyses.An abatement of human interference in the catchment areas of these rivers, and fodder/fuelwood plantation through the active participation of local people in their marginal land to decrease the human pressure on natural forests, are considered the two major easy, effective and economic methods to control the siltation hazard that is causing extensive deterioration to the environment in Nepal.Dr Govind P.S. Ghimire is Reader and Associate Professor in the Central Department of Botany at Tribhuvan University. Mr B.K. Uprety is an ecologist working on the Environmental Impact Study Project of His Majesty's Government, Nepal.     

A comparison in water quality: The UK and the CIS

Summary A comparison is made of major issues relating to drinking water and river water quality in the UK and the CIS (USSR). Historical and legislative aspects are briefly reviewed. In both countries there is an imbalance between the location of fresh water sources and the distribution of the population. In each country standards are used to define water quality. These standards tend to be more exacting in the CIS. In the UK derogations are used to produce a more relaxed standard. Failure to comply with drinking water standards is common in the CIS (on average 20 percent of samples). In the UK, data are recorded on a different basis, but it appears that deviations from nitrate and pesticide standards are common. In both countries' water supplies, pollution appears to be extensive with few overall signs of significant improvement. This is attributable partly to lack of effective enforcement and weak penalties for transgressors. There is a high level of public concern regarding water quality and health in both the CIS and the UK. As a consequence there are increasing signs in each country of a national determination to implement the legislation more effectively. Needs for further actions are identified.Dr Olga Bridges was born and educated in Russia. Since coming to the UK she has held posts on Soviet Studies in various universities. Dr Bridges' early research was in attitudes to languages and nationality, but more recently it has centred on attitudes to environmental issues. To further her knowledge of scientific aspects of environmental problems, Dr Bridges is currently taking the Advanced Diploma in Environmental Practice at Farnborough College of Technology, UK.     

Modelling environmental concern: Theory and application

Summary Human concern for the quality and protection of the natural environment forms the basis of successful environmental conservation activities. The social sciences have considered this concern as an area of research activity. In the present paper environmental concern research is considered and emphasis is placed upon studies which have depicted it in multiple dimensions. The results are then presented from research which has attempted to ask What are the dimensions of this concern? These findings suggest that individuals perceive different environmental issues differentially using multiple concurrent dimensions of evaluation. In general, issues are ascribed to a series of different categories which embody evaluations of; type (or referent) of issue, issue scale, environmental importance and personal importance of the issue.Dr Paul Hackett was until recently a staff member in the Consumer Research Unit of the Department of commerce at the University of Birmingham Business School. He is now on the staff of the Department of General Practice, University of Wales College of Medicine, Cardiff.     

Communicating About Smoke from Wildland Fire: Challenges and Opportunities for Managers

Wildland fire and associated management efforts are dominant topics in natural resource fields. Smoke from fires can be a nuisance and pose serious health risks and aggravate pre-existing health conditions. When it results in reduced visibility near roadways, smoke can also pose hazardous driving conditions and reduce the scenic value of vistas. Communicating about smoke, whether in the preparation phases before a planned burn or during a wildfire event, can enable those at risk to make informed decisions to minimize their exposure to smoke or choose alternate activities that mitigate smoke completely. To date, very little research has been completed on the social aspects of smoke, such as communication or public perceptions. Here, we present findings from an exploratory study that examined challenges and opportunities related to communication (within agencies or to the public) for management of smoke from wildland fires. Interviews were conducted in California, Oregon, Montana, and South Carolina among a purposive sample of individuals, who are involved in fire or smoke management. Findings indicate that smoke poses several challenges to management agencies. Findings also provide insight into potential strategies to address such challenges by improving communication in both inter- and intra-agency situations as well as with members of the public. In particular, prioritizing fire and smoke-related communication within agencies, allocating agency resources specifically for training in communication and outreach endeavors, taking advantage of existing resources including informal social networks among the public, and building long-term relationships both between agencies and with the public were viewed as effective.     

The effects of agrochemicals on an aquatic ecosystem : A case study from the Krian River basin,Malaysia

Summary The existing environment of the Krian River basin in Malaysia is not in its natural form for it has been much developed into agricultural lands (105,000 ha). The growing demand for agricultural lands requires further reclamation of swampy forests, which will result in an increased use of fertilisers (estimated 10 percent increase, from 29,500 t to 32,500 t), weedicide, dalapon (estimated 6 percent increase, from 187,620 kg to 199,530 kg) and pesticides, BHC and thiodan/endosulfan (estimated 2 percent increase, from 312 kg to 318 kg).Contrary to belief, the concern over increased levels of nitrogenous fertilisers and pesticides concentrations used in the existing agricultural projects is unfounded. The agrochemicals contribute insignificant amounts of contaminants into the aqueous system. Deleterious deterioration of water quality in the waterways is not apparent. The rich assemblage of icthyofauna comprises 14 freshwater fish species, 21 saltwater-freshwater interface species, like the freshwater prawn and marine fishes that have acclimatised to freshwater conditions, and 28 coastal- marine water fish species, two brackish water penaeids and three molluscs of commercial value. However, if the water quality data are used in isolation to interpret the consequences of large- scale usage of agrochemicals, the conclusion is inadequate and may be misleading. The impact of the flow condition in fields, the localised long-term effects like the fate and spatial distribution on the surrounding media (water, sediments and exposed aquatic life), bio-accumulation and bio-magnification should be considered. Though of no acute toxicity to hardy icthyofauna in the Krian Rice Irrigation basin, lipophilic organochlorines pose health risks to consumers of contaminated fishery products from these Krian rice fields.Dr Siaw-Yang Yap and Dr Hean-Tatt Ong graduated at the University of Malaya (Malaysia) with degrees in Aquatic Ecology and Plant Physiology respectively. Both currently have been involved in water quality criteria and standards development for aquatic life and irrigation uses in Malaysia. They have also contributed to environmental impact assessment projects, commissioned by the Department of Environment, Ministry of Science, Technology and Environment, Malaysia, the Ministry of Agriculture, Malaysia, and others. Dr Yap is an appointed member of the Freshwater Fish Specialist Group, Species Survival Commission/IUCN; she is involved in the "To Maintain Biological Diversity" project, aiming at conservation of genetic diversity of the threatened freshwater fish habitats and species in Asia. Dr Yap is also the specialist for water quality criteria and standards derivation for Malaysia and ASEAN tropical marine environments.     

Issues in the environmental sanitation of Lagos mainland,Nigeria

Summary Lagos is asserted to be the filthiest capital in the world. The influx of people into the metropolitan area has no corresponding technology to cope with the solid waste generated by the ever increasing population. Coupled with this lack of technology is the lack of adequate knowledge of the composition and generation rate of the refuse which has led to mismanagement of the environment. Paper waste is identified to constitute the major form of waste generated in Lagos and, in most cases, over 90 percent of the wastes generated are combustible, therefore, the use of incineration is recommended for effective management of the refuse.Dr Afolabi A. Adedibu and Mr A.A. Okekunle are members of staff in the Department of Geography at the University of Ilorin. Dr Adedibu, the senior author, has recently served as Foreign Curriculum Consultant to the Center for African Studies at the University of Florida. Dr Adedibu has presented earlier papers on Nigeria's solid waste management problems inThe Environmentalist, Vol.5, pp.123–127 and Vol.6, pp.63–68.     

COST MINIMIZATION OF NUTRIENT REDUCTION IN WATERSHED MANAGEMENT USING LINEAR PROGRAMMING1

ABSTRACT: Linear programming is applied to identify the least cost strategy for reaching politically specified phosphorus and total suspended solids reduction targets for the Fox-Wolf river basin in Northeast Wisconsin. The programming model uses data collected on annualized unit reduction costs associated with five categories of sources of phosphorus and total suspended solids discharge in each of the 41 sub-watersheds in the basin to determine the least cost management strategy. Results indicate that: (1) cost-effective nutrient reduction requires careful selection of geographic areas and source categories to address throughout the watershed; (2) agricultural sources are the most cost-effective to address in the basin; and (3) care should be exercised in setting nutrient reduction targets, given that there are likely to be significantly increasing marginal costs of nutrient reduction; the model predicts that lowering the most restrictive target by 33 percent would cut reduction expenditures by about 75 percent. Policy implications of the model include support for the investigation and potential development of institutional arrangements that enable cost-effective nutrient reduction activities to occur, such as the creation of an agency with authority over a given watershed, coordinated watershed management activities, or nutrient trading programs.     

Environmental damage — Environmental expenditure 1: Statistical evidence on the Federal Republic of Germany

Summary The conventional economic accounting systems have not played an enlightening role in statistically revealing the actual damage to the environment. They can, however, be methodologically improved; and they must be complemented by assessments of the ecological costs of the production process.In this article statistical evidence is provided on the level and structure of environmental damage and protection expenditures in the Federal Republic of Germany,i.e. on the environmental damage itself and on the environmental protection investments by industry and government, the capital stock for environmental protection, the total costs of and expenditures for environmental protection.Dr Christian Leipert and Prof. Udo Simonis are both regular contributors toThe Environmentalist (see 1989, pp.171–183; 1990, pp.25–38). Prof. Simonis is Director of the International Institute for Environment and Society (Wissenschaftszentrum) and Dr Leipert a member of its research staff.     

The environmental impact of a chloro-alkali factory in a river basin in Eastern India

Summary It has been established that the electrodes of the dialyser in a chloro-alkali plant in Eastern India release mercury beyond the permissible limits into the River Koel. Mercury in elemental form, as well as certain organo-mercury compounds, including methyl mercury, have been detected at a distance of 25 km from the discharge point. Even at a distance of 5–10 km, the mercury content of the sediment may be as high as 0.6–3.2 mg kg^–1 above the value of sediment upstream of the plant. This sediment itself is contaminated, probably by battery and paint factories, etc., still further upstream. Thus, the chloro-alkali factory has contributed 60–320 times above the permissible limit (0.01 mg kg^–1) of mercury release, at a distance of 5–10 km from the point of release. Furthermore, various phytoplankton and zooplankton have been contaminated, leading to very high mercury contents in certain fish. This food chain, therefore, threatens man himself.Dr Sajalendu Nanda is currently a Research Associate at Bangur Institute of Neurology in Calcutta. He possesses an MSc in Environmental Biology and a PhD in Ecology. His address for correspondence is c/o Dr P.K. Tapaswi, Professor-in-Charge at the Biological Sciences Division of the Indian Statistical Institute.     

Fly ash for the treatment of Zn(II) rich effluents

Summary The ability of fly ash to remove Zn(II) from water by adsorption has been tested at different concentrations, temperatures and pH of the solution. It was found that low adsorbate concentration, small particle size of adsorbent and higher temperature favoured the removal of Zn(II) from aqueous solution. The Langmuir isotherm was used to represent the equilibrium data at different temperatures. The apparent heat of adsorption has been found to be 17.325 Kcal mol^–1, which indicates the process to be endothermic. The uptake of Zn(II) is diffusion controlled and the mass transfer coefficient is 3.56 × 10^–5 cm s ^–1.The maximum removal was noted at pH 7.5. Dr V.N. Singh is Professor and Head of the Department of Applied Chemistry, Dr A.K. and Prof. D.P. Singh are members of the Department of Mining Engineering; all are situated in the Institute of Technology at Banaras Hindu University.     

Community-based Organizations and Neighbourhood Environmental Problem Solving: A Framework for Adoption of Information Technologies

Community-based organizations (CBOs) today seek improved capacity to address environmental problems in urban neighbourhoods. Many seek access to information technologies such as the Internet and Geographic Information Systems (GIS) to expand information about their neighbourhood's environmental quality to support their planning and service efforts. Experience with the Internet has been bolstered somewhat by programmesto create community networks. This experience and experience with GIS in planning at the municipal and state levels reveals a set of technical, organizational and personal prerequisites that bolster successful and effective adoption of information technologies. This paper reviews these prerequisites as they pertain to CBOs and makes recommendations for transactions that could enhance CBO adoption of the Internet and GIS to address environmental problems in urban neighbourhoods. The paper concludes that a constellation of prerequisite conditions, most predominantly data availability problems, staff skill acquisition and staff retention problems, offer the greatest challenges for CBOs seeking to adopt information technologies to manage environmental problems more effectively.     

铁合金电炉烟尘的性质与低温固结研究

本文研究了硅铁电炉布袋除尘收集的烟尘性能，烟尘低温固结球团的性能和工艺方法。研究结果表明，硅铁电炉烟尘中ＳｉＯ２ 约占９０ － ９５ ％ ，其它组分含量较低，有利于进行回收利用。烟尘密度小、粒度细、表面活性差、成球性能差。采用添加粘结剂进行自然养护和低温固结处理，均能获得强度较好的固结球团，能够加入铁合金炉回收利用。     

ALGAL BLOOM PROBABILITY IN A LARGE SUBTROPICAL LAKE1

ABSTRACT: Algal blooms, defined as chlorophyll α concentrations greater than 40 μg l^?1, are common in Lake Okeechobee, Florida. Using logistic regression techniques, we have developed equations that relate limnological variables to algal bloom occurrence in four distinct open-water regions of this large shallow lake: central pelagic, northwest, southwest, and a transition region between the western and pelagic regions. Wind velocity and total phosphorus, which are closely related to resuspended material in the central region, are negatively related to algal bloom occurrence there. In the transition region, algal bloom occurrence is positively related to total nitrogen and wind velocity. Algal bloom occurrence is strongly and positively related to total nitrogen and total phosphorus concentrations in the western regions. The logistic regression model predicts an algal bloom probability greater than 95 percent in the northwest region when total phosphorus exceeds 0.10 mg l^?1 and total nitrogen exceeds 2.5 mg l^?1. In the southwest region the model predicts algal bloom probability of 100 percent when total phosphorus exceeds 0.10 mg l^?1 and total nitrogen exceeds 2.8 mg l^?1. Given 1994 mean total phosphorus concentrations of 0.05 and 0.04 mg l^?1 in the northwest and southwest regions, respectively, total nitrogen would have to remain below 1.32 and 1.43 mg l^?1, respectively, to keep the algal bloom probability below 10 percent. Because the lake is heterogenous, such nutrient standards should be considered on an in-lake regional basis for Lake Okeechobee.     

NITRATE CONCENTRATIONS IN KARST SPRINGS IN AN EXTENSWELY GRAZED AREA1

ABSTRACT: The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian Region. Karst areas comprise about 18 percent of the Region's land area. An estimated one-third of the Region's farms, cattle, and agricultural market value are located on karst terrain. Nitrate concentrations were measured in several karst springs in Southeastern West Virginia in order to determine the impact of animal agriculture on nitrate pollution of the karst ground water system. Karst basins with 79, 51, 16, and 0 percent agriculture had mean nitrate concentrations of 15.8, 12.2, 2.7, and 0.4 mg/l, respectively. A strong linear relationship between nitrate concentration and percent agricultural land was shown. Median nitrate concentration increased about 0.19 mg l^-1 per percent increase in agricultural land. Weather patterns were also found to significantly affect the median nitrate concentrations and the temporal variability of those concentrations. Lower nitrate concentrations and lower temporal variability were observed during a severe drought period. It was concluded that agriculture was significantly affecting nitrate concentrations in the karst aquifer. Best management practices may be one way to protect the ground water resource.     

EFFECTIVE USE OF LANDSAT DATA IN HYDROLOGIC MODELS1

ABSTRACT: In a cooperative demonstration project, NASA and the U.S. Army Corps of Engineers (Corps) compared conventional and Landsat-derived land-use data for use in hydrologic models, and the resulting discharge frequency curves were analyzed. When a grid-based data-management system was used on a cell-by-cell basis (size about 1.1 acres or 0.45 hectare), Landsat classification accuracy was only 64 percent, but, when the grid cells were aggregated into watersheds, the classification accuracy increased to about 95 percent. When both conventional and Landsat land-use data were input to the HEC-1 model for generating discharge frequency curves, the differences in calculated discharge were judged insignificant for subbasins as small as 1.0mi² (2.59 km²). For basins larger than 10mi² (25.9km²), use of the Landsat approach is more cost-effective than use of conventional methods. Digital Landsat data can also be used effectively by local and regional agencies for hydrologic analysis by incorporating the data into grid-based data-management systems. The transfer of this new technology is well under way through inclusion in some Corps training courses and through use by both county government personnel and private consultants.