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1.
Latin America comprehends notable variations in terms of natural environment, availability of natural resources, living standards, and demographic patterns. Latin America is a mosaic of cultures, post- and pre-Columbian. The rich variety of life forms discovered and described by chroniclers and traveling naturalists in the Neotropics contributed to the proposal, in mid-XVIIIth century, of a new system of classification and a scientific code of nomenclature for all organisms. Biodiversity was, for many centuries, a source of resources to be exploited in natura. In scientific circles, its inventory became the domain of taxonomists. But modern technology showed how important the miriad of life forms really are as sources of chemical molecules to be engineered as drugs and reassembled as novel manufactured products. We are on the brink of a new agricultural and medical revolution, thanks to the techniques of genetic engineering, which will lead eventually to the elimination of hunger and malnutrition.In this essay, the Brazilian environmental and social heterogeneity will serve as an example to illustrate some key points, which have influenced sustainability policies. The Amazon deforestation and indigenous knowledge (IK), subjects often associated with areas of high biodiversity, are usually the focus of environmental debates. The importance of IK in integrating development, reducing poverty and sustainability are considered together with the intellectual property rights of native populations.In the World Summit on Sustainable Development (WSSD) Implementation Plan, a few paragraphs were dedicated to Latin America, because of the pre-existing Action Platform on the Road to Johannesburg 2002, approved in Rio de Janeiro in October 2001. This paper calls attention to the need to draw up specific environmental policies for a region which shows an extremely high cultural and biological diversity, associated with a high availability of forests and water, among other resources.  相似文献   

2.
In early 1980 an extension agent was assigned to the rural municipality of Bangui, Ilocos Norte, Philippines to work on development projects – in particular the improvement of the supply of safe water for drinking and sanitation. After many months of visiting spring sites and meeting with community leaders, a small part of the municipality was selected to build a gravity fed piped water system. Although the system took many months to plan, identify funding and construct, the 600 community members were ultimately rewarded with house to house connections that enabled them to achieve per capita water consumption levels above the minimum levels recommended by the World Health Organization. Of course, money was critical to ensure the project’s success, but many other factors played an equally critical role. For instance, without the active participation of the community and the unwavering support of the community leadership the project would not have survived the initial planning stage. Also, the extension agent played a critical role by acting as a conduit between funding agencies, the Bureau of Public Works and the community. The primary lesson to be learned from this experience is that the success of rural development projects is largely driven by the synergy between the community, technical support, financial support, and agents of change such as extension agents. If any of these ingredients had been lacking, the project result would likely have been far different.  相似文献   

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4.
Polybrominated diphenyl ethers (PBDE) are used as flame retardants in a wide variety of products. As part of the Integrated Exposure Assessment Survey (INES), this study aimed to characterize the exposure of an adult German population using duplicate diet samples, which were collected daily over seven consecutive days, and indoor air and house dust measurements. Our study population consisted of 27 female and 23 male healthy subjects, aged 14–60 years, all of whom resided in 34 homes in southern Bavaria. In these 34 residences the air was sampled using glass fiber filters and polyurethane foams and the dust was collected from used vacuum cleaner bags.The median (95th percentile) daily dietary intake of six Tetra- to HeptaBDE congeners was 1.2 ng/kg b.w. (3.3 ng/kg b.w.) or 67.8 ng/day (208 ng/day) (calculated from the 7-day median values of each study subject). Concentrations in indoor air and dust (cumulative Tri- to DecaBDE congener readings) ranged from 8.2 to 477 pg/m³ (median: 37.8 pg/m³) and 36.6 to 1580 ng/g (median: 386 ng/g), respectively. For some congeners, we identified a significant correlation between air and dust levels.The median (95th percentile) blood concentration of total Tetra- to HexaBDE congener readings was 5.6 (13.2) ng/g lipid. No significant sex differences were observed, but higher blood concentrations were found in younger participants. Using a simplified toxicokinetic model to predict the body burden from exposure doses led to results that were of the same order of magnitude as the measured blood concentrations.Based on these measurements and given our exposure assumptions, we estimated for the total tetra- to heptabrominated congener count an average (high) comprehensive total daily intake of 1.2 ng/kg b.w. (2.5 ng/kg b.w.). Overall, our results suggest that dietary exposure is the dominant intake pathway at least in our study population, responsible for 97% (average intake) and 95% (high intake) of the total intake of an adult population.  相似文献   

5.
This paper presents a new general, process-based river model for substances such as radionuclides from single pulse fallouts. The new model has been critically tested using data from 13 European rivers contaminated by radiocesium from the Chernobyl accident. This modelling approach gives radionuclide concentrations in water (total, dissolved and particulate phases; and also concentrations in sediments and fish, but the latter aspects are not discussed in this paper) at defined river sites. The model is based on processes in the upstream river stretch and in the upstream catchment area. The catchment area is differentiated into inflow ( approximately dry land) areas and outflow ( approximately wetland) areas. The model also accounts for time-dependent fixation of substances in the catchment. The catchment area sub-model is based on a previous catchment model, which has been tested with very good results for radiocesium, radiostrontium and Ca-concentrations (from liming operations). The new river model is simple to apply in practice since all driving variables may be readily accessed from maps and standard monitoring programs. The driving variables are: latitude, altitude, continentality, catchment area, mean annual precipitation, soil type (percentages or organic and sandy soils), fallout and month of fallout. Modelled values have been compared to independent empirical data from 10 rivers sites (91 data on radiocesium in water) covering a wide domain (catchment areas from 4000 to 180 000 km(2), precipitation from 500 to 960 mm/yr and fallout from 1700 to 660 000 Bq/m(2)). The new model predicts very well--when modelled values are compared to empirical data, the slope is perfect (1.0) and the r(2)-value is 0.90. This is good giving the fact that there are also uncertainties in the empirical data, which set a limit to the achieved predictive power, as expressed by the r(2)-value.  相似文献   

6.
Most models for transfers of radionuclides through the food chain typically assume that the radioactivity is initially deposited in chemically available forms. It is known, however, that releases of radionuclides in the form of hot particles may significantly influence their environmental transfers and uptake to the food chain. This study presents models for time changes in 90Sr and 137Cs in milk which incorporate hot particle contamination using observed rates of hot particle dissolution following the Chernobyl accident. A general equation is presented for the influence of hot particles on overall ingestion doses. As expected from previous work, fallout of hot particles significantly influences time changes in radionuclide activity concentrations in foodstuffs. It is also shown that incorporation of radionuclides in hot particles influences time-integrated ingestion doses. For a situation in which a large proportion (90–100%) of fallout is in slowly dissolving hot particles, time-integrated ingestion doses from 90Sr and 137Cs are reduced by a factor of approximately two compared to the case where all radioactivity is deposited in bioavailable forms. However, the influence of rapidly dissolving hot particles on time-integrated ingestion doses is relatively minor. Remaining significant uncertainties in dose estimates are discussed.  相似文献   

7.
The appearance of Steven Schwarze's essay, “Environmental Melodrama” (Schwarze, 2006) as the lead article in a recent issue of The Quarterly Journal of Speech marks an important moment of recognition for environmental communication scholarship. Schwarze's essay demonstrates how studies of environmental rhetoric can contribute to rhetorical theory more generally, while addressing practical questions regarding the rhetorical aspects of environmental conflict. The contributors to this forum respond to Schwarze's arguments, drawing in part upon their own case studies of rhetorical action and narrative in environmental conflict.  相似文献   

8.
It is known that pseudoviviparous plant taxa are most numerous in the Arctic and high mountain regions, where they sometimes account for a noticeable part of the local flora and play an important phytocenotic role. The complex of pseudoviviparous taxa is an interesting model for investigating the processes of hybridogenic speciation, as various mechanisms stabilizing the hybrid genetic systems proved to be effective in them. In particular, this concerns vast and taxonomically complex groups such as the genera Deschampsia, Festuca, and Poa.In this paper, published data on the taxonomy, chromosome numbers, and distribution of pseudoviviparous grasses in the Arctic regions and subarctic mountain systems are reviewed.  相似文献   

9.
10.
Development of benthic communities on rocks from the interdisciplinary test site near Cape Berezovyi (southern Baikal) is analyzed. Rock plates were placed on the bottom in the shallow-water zone of Baikal for six months, and a community consisting of microorganisms, microphytobenthos, and meiobenthos developed on them. The development and activity of hydrobionts depended on the chemical composition and structure of the rock. Marble and granite plates were populated by them more selectively than amphibolite plates. It is supposed that the biota plays an important role in destruction of rocks in the shallow-water zone of Baikal.  相似文献   

11.
21世纪我国国土资源可持续利用的形势及战略措施   总被引:15,自引:0,他引:15  
本文分析了我国国土资源可持续利用的形势,指出了国土资源在经济发展中的地位和作用,提出了国土资源可持续利用的任务和战略措施。  相似文献   

12.
It was shown that along the Eastern Ural Radioactive Trace central axis, about 100 km in length, decrease of the 90Sr and 137Cs deposition densities in soil samples may be described as an exponential function. At the western and eastern periphery of the trace, 90Sr contents in soils approached to the background level due to global fallout. 90Sr and 137Cs concentrations in seeds of some herbaceous plants have been determined. The radionuclide concentrations and the resulting dose loads upon plant seeds showed an excess over the background level of about two or three orders of magnitude.  相似文献   

13.
It is shown here that one burns 1 gallon of gasoline equivalent in fossil fuels to produce 1 gallon of gasoline equivalent as ethanol from corn. When this corn ethanol is burned as a gasoline additive or fuel, its use amounts to burning the same amount of fuel twice to drive a car once. Therefore, the fuel efficiency of those cars that burn corn ethanol is halved. The widespread use of corn ethanol will cause manifold damage to air, surface water, soil and aquifers. The overall energy balance of corn conversion to ethanol demonstrates that 65% of the input energy is lost during the conversion. Carbon dioxide sequestration by corn is nullified when corn ethanol is burned, and there will be additional carbon dioxide, nitrous oxides, and sulfur oxide emissions from the fossil fuels used to produce the ethanol. Students in the Spring 2003 CE24 Freshman Seminar offered at U.C. Berkeley by the Civil and Environmental Engineering Department Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   

14.
Sustainable development advocates for a balance between socio-economic development and the environment in the pursuit of human advancement. In Africa, high population growth and inadequate infrastructure in urban areas exert pressure on the environment and this threatens the health and wellbeing of urban residents. The population of the African continent until the 1960s was predominantly rural. This scenario has taken a swift turn and some of the major shifts in the global urbanisation process are taking place on the continent. Factors including natural increase in the population, rural–urban migration, strife and hunger leading to the internal displacement of populations have exacerbated the urbanisation process in Africa. The situation has been worsened by the imposition of Western development policies, including structural adjustment programmes on African nations, which has eroded the subsistence base of rural agricultural communities and further ignited rural urban migration. The failure of industry to absorb the increasing labour force has created massive unemployment and deepening poverty crisis in urban centres. Inadequate provision of infrastructure and services to meet the growth in urban populations has resulted in inefficient spatial development of urban centres, the proliferation of squatter settlements, inadequate basic amenities including potable water, sanitation and waste disposal. Poor environmental sanitation has resulted in the upsurge of infectious diseases and deteriorating urban health. Urban populations in Africa are also the worst affected by newly emerging diseases, particularly HIV/AIDS. The poor bear a disproportionately large share of the problems due to their particular vulnerability to environmental and health risks. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   

15.
Traditional crop landraces play dynamic roles in the expression of native biological and cultural diversity via their central position in the genetic resource base, agroecosystems and social heritage of indigenous peoples. Farmer varieties provide farmers with an “agricultural survival kit” for household welfare and for adaptation to changing conditions. These varieties meet local cultural practices and environmental constraints, and play an intrinsic role in cultural survival by constituting a living repository of ancestral customs including cultivar-specific recipes, songs, handicrafts, stories of origin, and unique planting, harvesting, processing, and storage rituals and techniques. The centrality of rice in Southeast Asian agricultural and social systems, contrasted with the significant erosion of rice-based biological and cultural diversity in native communities, calls for increased attention to the links between traditional rice varieties and indigenous rice-based customs. This study represents the research efforts of rice farmers pertaining to the Tado clan, a Kempo Manggarai community on Flores␣Island, in association with USA academicians. Research results demonstrate: (i) a complex suite of upland rice-based ethnobotanical traditions; (ii) significant and␣dynamic regional flux and dissemination of “old” and “new” landraces; (iii)␣community-level maintenance of distinct genotypes across a range of microenvironments; (iv) localized “extinctions” of ancestral landraces within 1–2 generations and a concomitant loss of related traditions; and (v) the contributions of a collaborative (indigenous and academic) approach to ethnographic and agronomic research.  相似文献   

16.
Harvesting of non-timber forest products is an integral component of rural livelihoods throughout the developing world. At times this is at odds with conservation objectives. Reconciliation of the two requires examination of local level contexts and needs. This paper reports on the harvesting needs for Ischyrolepis by a rural community in South Africa, against the setting that they had recently been prohibited from harvesting by the local conservation officials. Interviews were conducted with conservation officials to understand the reasoning for the prohibition. Local demand for Ischyrolepis was assessed by household surveys, as well as in-depth interviews with traders. The density and size class distribution of Ischyrolepis was determined using transects. The total annual demand for Ischyrolepis was determined to be approximately only 2.7% of the standing crop. The bulk of the annual demand was for small-scale trade, the income from which was a primary source of income for the few harvesters. Very little evidence could be found indicating that harvesting was damaging the resource or its habitat, and local knowledge suggested that the abundance of the species was stimulated by harvesting. Even if market demand were to increase, the size of the shoots required means that less than 20% of the standing crop could be harvested annually. Current regulations around harvesting are in a state of revision, and hence confusion prevails regarding if harvesting is permissible, and if so, under what conditions, which is detrimental to both conservation and livelihoods. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   

17.
The World Summit on Sustainable Development (WSSD), held in Johannesburg during 26 August and 4 September 2002, was a truly remarkable event, not least because it identified and committed the world community to what has to be done to realise Agenda 21 objectives. Discussion begins with the "means of implementation" of the Johannesburg Plan of Implementation (JPI). Education for, and raising awareness of, sustainable development are the key commitments in the "means of implementation". The issues central to these commitments are discussed. The crucial role of moral philosophy in education for sustainable development is then discussed. Defining the "problem" as lack of progress (in fact negative progress between Rio and Johannesburg) towards global sustainable development, a cause–effect relationship of the "problem" is developed based on a systematic and logical analysis. It shows that the "cause" is West's profoundly materialistic, environment-degrading and exploitative attitude and activities to satisfy grossly unsustainable, hedonistic and insatiably avaricious Western life-styles – life-styles that are held up by the West as "ideal" fruits of economic "development" to be aspired by all. The "effects" are pollution of air, water and soil; mounting loss of biodiversity, ecosystems and species; relentlessly widening north–south divide, etc. It is argued that while science and technology can address some of the "effects", they cannot address the "cause". Only moral philosophy can by fundamentally re-orienting moral values genuinely to respect nature and the environment. Based on sound and tested principles of Educational Psychology, a proposal is then made for including moral philosophy in the formal curricula (content and pedagogy) of primary, secondary and higher education for instilling in children and young people genuinely environment-respecting moral values. To this end a generic syllabus for the secondary level is proposed. Finally, it is argued that if the scientific community really believes that science or technology alone can radically change the pervasive environment-degrading moral values to those that genuinely respect the environment, thus paving the way to real global sustainability, then it must demonstrate how this could be done and explain why, despite their abundant science and technology, the developed nations are the biggest polluters and consumers with grossly unsustainable life-styles. Certainly, examples would be much more convincing than rhetoric or tired old clichés about how science and technology alone could deliver global sustainable development.  相似文献   

18.
Studies have been carried out to determine the natural radioactivity in some building materials (bricks, tiles, marble and ceramics) and their associated radiation hazard. The radioactivity concentrations of 226Ra 232Th and 40K were measured using a gamma spectrometer with a Hp–Ge detector. The activities of 238U and 234U were measured using an alpha-spectrometer with a surface barrier detector after applying a radiochemical procedure. The 234U/238U isotopic ratios were calculated. The radium equivalent activities and the radiation hazard index associated with the natural radionuclides were calculated. A computer program was developed and applied to calculate the dose rate a person will receive from the walls of a room constructed from the studied building materials.  相似文献   

19.
The isotope ratios δ13C and δ15N and the contents of nitrogen, carbon, and mineral substances have been studied in the leaves of Ephedra sinica, Allium polyrhizum, and Stipa glareosa plants growing separately or together under arid conditions of the Gobi (Mongolia). The contents of nitrogen, mineral substances, and δ15N have proved to decrease when these species grow together, providing evidence that they compete for environmental resources. The nitrogen content decreases to the greatest extent in E. sinica due to the low competitiveness of this species. The direction of change in δ13C in E. sinica is opposite to that in A. polyrhizum and S. glareosa. Differences in physiological mechanisms of adaptation to stress between these species provides a basis for attributing them to different functional groups and for predicting the result of their competition upon changes in climatic conditions.  相似文献   

20.
Motivated by the detection of 131I in river sediment in routine long-term surveillance samples, a systematic short-term study of the wastewater treatment chain was planned and conducted. Inflow, effluent and primary sludge were collected on a daily basis during two weeks at a regional wastewater treatment plant. Samples were investigated by gamma spectroscopy. Four medically used isotopes could be identified (131I and 99mTc regularly, 153Sm and 123I sporadically). The concentration levels coincide well with literature data for 131I, and with our own long-term data for 131I and 99mTc for the same plant. Cosmogenic 7Be activity in primary sludge correlated well with rainfall intensity. Surface sediment was sampled at low tide at both shores of the river, up- and downstream of the plant. 131I was identified in all samples, with a sharp maximum (about 100 Bq kg−1 d.m.) at the discharge point of the plant and lower levels elsewhere, decreasing monotonically in downstream direction. 7Be and 137Cs showed the same behaviour, but no peak at the discharge point. Predictions from simple equilibrium models for the transport and sedimentation of 131I show good agreement with the experimental data and suggest that the wastewater treatment plant is the main source for this isotope.  相似文献   

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