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911.
Since the 1950s afforestation of degraded land has been the principal means of combatting erosion in a seasonally arid area of central Spain. In the 1970s tree planting of steep hillsides and gully sides was preceded by bench terracing. Experimental sites have been established to monitor runoff and soil losses under mature Pinus forest, 12-year-old Pinus forest, and Cistus matorral. The experiment is being conducted at three scales: large gully or small watershed (c. 3.5 ha), runoff erosion plot (10–21.5 m2), and rainfall simulation plot (1 m2). Monitoring began in October 1992. Discharge was recorded continuously, while sediment loss and soil moisture content were measured on a storm basis. The paper presents summary data on runoff and soil erosion for the three scales and comments on relationships between land management, site characteristics, and these losses. We stress the crucial role of vegetation and its interrelationship with soil properties such as structure and aggregate stability. Matorral was effective in combatting water and soil loss, but we question the practice of afforesting seasonally arid, steeply sided areas that have highly erodible soils.  相似文献   
912.
The presence of natural organic matter (NOM) strongly impacts drinking water treatment, water quality, and water behavior during distribution. Dissolved organic carbon (DOC) concentrations were determined daily over a 22 month period in river water before and after conventional drinking water treatment using an on-line total organic carbon (TOC) analyzer. Quantitative and qualitative variations in organic matter were related to precipitation and runoff, seasons and operating conditions. Following a rainfall event, DOC levels could increase by 3.5 fold over baseflow concentrations, while color, UV absorbance values and turbidity increased by a factor of 8, 12 and 300, respectively. Treated water DOC levels were closely related to the source water quality, with an average organic matter removal of 42% after treatment.  相似文献   
913.
A comparative study was undertaken at two different sites (one urban, one suburban) in Greater London in order to examine whether there was a relationship between publicly available air quality data and the public's perception of air quality. Perceptions of air quality and its role as a potential quality of life indicator was also investigated. A total of 200 people were interviewed in Wood Green and Wimbledon in 1999 and air quality data were obtained simultaneously from the nearest appropriate monitoring station. The study has enabled a comparison between the public's perception of air quality and the actual monitored concentration values. The survey results reveal how seriously the public regards air pollution from road traffic in terms of their quality of life and identifies the attitudes of the public to nuisance from road traffic. The results reveal that the public's perception of air quality is not a reliable indicator of the actual levels of air pollution in their area. The results also revealed that air pollution issues generated as a result of road traffic are of high importance in terms of people's quality of life when compared to other aspects of their quality of life. The study revealed that residents in the urban area (Wood Green) were more disturbed by road traffic than residents in the suburban area (Wimbledon). Out of all the disturbances listed, it was found that residents were more disturbed by vehicle-derived fumes, dust and dirt than other aspects of road traffic related nuisance. The TELETEXT/CEEFAX service on air quality was little used by the public as a means of obtaining information on air pollution.  相似文献   
914.
Total suspended particulate (TSP) samples were collected weekly over a period of one year at four European sites during 1995/6. Two sites were in London-a Central London site (CL, St Paul's Cathedral) and a suburban North London site (NL, Bounds Green); the other two sites were in Porto, Portugal and Vienna, Austria. TSP was collected using a low volume sampler. Organic carbon (OC) and elemental carbon (EC) concentrations were measured using a thermal-optical carbon analyser. Parallel samplers collected TSP for subsequent GC-MS analysis of thirty-nine combustion-associated organic compounds; 16 polyaromatic hydrocarbons (PAHs) and 23 n-alkanes. OC and EC correlate well at all sites (r2 = 0.39-0.65), although the London inter-site correlations were low, suggesting that local sources of OC and EC have a significant influence on local concentrations. Concentrations do not vary widely across the four urban sites, despite the significant differences in urban characteristics. Seasonal patterns of OC:EC ratios were similar at the London and Vienna sites, with highest ratios in autumn and winter, and annual mean OC:EC ratios were identical at these sites. The Carbon Preference Index (CPI) indicated vehicle emissions to have a stronger influence over particulate concentrations at the Vienna and central London sites; there was a stronger biogenic signature in north London and Porto. In addition, two PAH compounds (pyrene and fluoranthene) previously associated with diesel exhaust, were correlated with OC and EC concentrations at the London and Vienna sites.  相似文献   
915.
The interactions between Zn and Cd on the concentration and tissue distribution of these metals in lettuce and spinach were studied at levels corresponding to background and Zn-Cd contaminated sites. Plants were grown in nutrient solutions containing 0.398-8.91 microM Zn and 0.010-0.316 microM Cd. Cadmium accumulated more in old than in young leaves of both crops at any solution Cd level, whereas Zn followed that pattern only at Zn levels > or = 3.16 microM. Increasing solution Cd increased Zn concentrations in young leaves of lettuce but not of spinach, regardless of Zn levels. Cadmium concentrations in young leaves of both crops decreased exponentially with increasing solution Zn at low (0.0316 microM) but not at high (0.316 microM) solution Cd. The Zn: Cd concentration ratios in young leaves of lettuce and spinach grown at 0.316 microM Cd became greater as the solution Zn increased. Cadmium and Zn concentrations in young leaves were related more closely to the relative concentrations of Zn and Cd in solution than were the concentrations in old leaves, especially in lettuce. Studies of Zn-Cd interactions and Cd bioavailability should differentiate between basal and upper leaves of lettuce and spinach. Compared to Cd-only pollution, Zn-Cd combined pollution may not decrease Cd concentrations in lettuce and spinach edible tissues, but because it increases their Zn concentrations it lowers plant Cd bioavailability.  相似文献   
916.
Changes in concentrations of soluble reactive phosphorus (SRP), excess partial pressure of carbon dioxide (EpCO2), and chlorophyll-a were examined for two rivers in the in the upper Thames catchment: the main river Thames at Wallingford and a chalk stream tributary, the River Kennet. Sampling began in the spring of 1997 and has covered extremes in river flow conditions. During the sampling period there was a dramatic reduction in phosphorus (P) inputs from the introduction of effluent P-treatment at sewage treatment works, as a result of the EU Urban Wastewater Treatment Directive. Despite major reductions in baseflow SRP concentrations in the River Kennet, from around 700 μg-P L-1 to around 100 μg-P L-1, observations of aquatic plant communities indicate overall degradation in ecological quality since effluent P-treatment was introduced. The degradation was associated with a spring and summer decline in growth of Ranunculus, a macrophyte of high conservation value in chalk streams, particularly from 2000 onwards, linked to shading by epiphytic algae. Although the EpCO2 records indicate a reduction in primary productivity since effluent P-treatment, the River Kennet may have become more sensitive to epiphyte blooms. Episodes of epiphyte proliferation appear to be linked temporally to small increases in SRP concentrations (typicallyabove a 100 μg-P L-1 threshold) under summer baseflow conditions. The in-stream system is highly complex and individual processes and causality are difficult to resolve, particularly given changes in river flows linked to background climatic variability and limited availability of biological data. This study demonstrates the need for integrated long-term biological and chemical monitoring of river systems subject to major perturbations to assess timescales required to produce new dynamic equilibria in ecosystem response.  相似文献   
917.
Science of odor as a potential health issue   总被引:2,自引:0,他引:2  
Historically, unpleasant odors have been considered warning signs or indicators of potential risks to human health but not necessarily direct triggers of health effects. However, citizen complaints to public health agencies suggest that odors may not simply serve as a warning of potential risks but that odor sensations themselves may cause health symptoms. Mal-odors emitted from large animal production facilities and wastewater treatment plants, for example, elicit complaints of eye, nose, and throat irritation, headache, nausea, diarrhea, hoarseness, sore throat, cough, chest tightness, nasal congestion, palpitations, shortness of breath, stress, drowsiness, and alterations in mood. There are at least three mechanisms by which ambient odors may produce health symptoms. First, symptoms can be induced by exposure to odorants (compounds with odor properties) at levels that also cause irritation or other toxicological effects. That is, irritation--rather than the odor--is the cause of the health symptoms, and odor (the sensation) simply serves as an exposure marker. Second, health symptoms from odorants at non-irritant concentrations can be due to innate (genetically coded) or learned aversions. Third, symptoms may be due to a co-pollutant (such as endotoxin) that is part of an odorant mixture. Objective biomarkers of health symptoms must be obtained, however, to determine if health complaints constitute health effects. One industry that is receiving much attention, worldwide, related to this subject is concentrated animal production agriculture. Sustainability of this industry will likely necessitate the development of new technologies to mitigate odorous aerial emissions. Examples of such "environmentally superior technologies" (EST) developed under the initiative sponsored through agreements between the Attorney General of North Carolina and Smithfield Foods and Premium Standard Farms are described.  相似文献   
918.
This article discusses the current framework of coastal decision making which tends to exclude participation by individuals and those without a strong institutional representation. A distinction is drawn between institutional and local stakeholders to illustrate weaknesses in the existing decision framework. It is argued that particularly in the coastal environment, the relationship between changes in physical form and changes in social welfare is critical to understanding how decision making may engage more fully with local stakeholders and ultimately improve decision outcomes. A reordering of stakeholder engagement in decision systems at the coast is proposed and a framework is outlined which enhances the capacity of local stakeholders to influence decision making.  相似文献   
919.
Book reviews     
“Water Planning and the Regions”

Edited by P. J. Purdy, R. S. A.

Discussion Paper No. 9, 1977, £1.50.

Tenant participation in council housing management; Housing Development.

Directorate Occasional Paper 2/77, DoE London, 1977.

Getting tenants involved: a handbook on systems of tenant participation in housing management; DoE London, 1977.

La politica dei servizi tra razionalizzazione e rinnovamento

Alberto L'Abate (1978)

Marsilio Editori, Padova, pp. 316

Handbook for Environmental Planning: the social consequences of environmental change.

J. McEnvoy & T. Dietz (1977)

New York, J. Wiley, pp. 323. Price £15.50

Planning and Urbanism in China

Progress in Planning Vol. 8, Part 2, Fo. 1 N. Jeffrey and M. Caldwell, pp. 97–182, 1977

Pergamen, £4.00

The European Community's Regional Fund

Ross B. Talbot

Progress in Planning, Vol. 8, Part 3, pp. 183–281

Pergamon Press, 1977

Providing the Posh Words

W. Hampton, DoE

1978. £1.50. 60pp.

Four Titles on Conservation

A Critical Bibliography of Building Conservation. John F. Smith. Mansell, London 1978. 207 pages including index. Hard back, £12.90.

Conservation and Planning. Alan Doby. Hutchinson — The Built Environment. 1978. 173 pages. Some illustrations. Paper back, £3.25.

A Study in Conservation. Winston Barnett and Cyril Winskell. Oriel Press, 1977. 45 pages, in English, French and German. Illustrated. Paper back, £3.75.

Interpreting the Conserved Environment. Working Paper No. 29. Brian Goodey. Oxford Polytechnic Department of Town and Country Planning, 1977. 65 pages. Paper back, not priced.

“Belgium”, R. Riley, £3.25, 205 pp.

“The Netherlands”, D. Pinder, £3.25, 194 pp.

“The USSR”, J. C. Dewdney, £3.25, 262 pp.

Development Strategy of Bangladesh

Nurul Islam

Oxford, Pergamon Press, 1978, 109 pp.  相似文献   

920.
ABSTRACT: Indiana has embarked on a program to assess the condition of its infrastructure and to plan for its future. The perspective of this planning differs from the traditional “master plan” approach — instead, the focus is on competitiveness for economic development. The initial work on the water and sewerage competitiveness of the infrastructure includes: (1) a comparative analysis of the water resources and infrastructure of Indiana and its industrial midwestern neighbors; (2) a technology scan to identify possible technological opportunities that may be important for Indiana; and (3) a set of recommendations for future planning. This work is preliminary in nature but should serve as a starting point for continued strategic planning over the next decade for positioning of Indiana's water and sewerage infrastructure as a key element in the economic growth equation.  相似文献   
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