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191.
An investigation of bacteria found in rubber processing wastes was carried out. Rubber wastes which include effluents from washing tanks and natural rubber waste serum (NRWS) were obtained from Greenpark Rubber Industries Limited, Umutu, Delta State, Nigeria. Five bacterial species were isolated from the wastes. These include Arthrobacter sp., Bacillus sp., Lactobacillus sp., Psuedomonas sp. and Streptococcus sp. Apart from these a number of coliforms were also encountered. Arthrobacter sp. was found to be the dominant species and its potential to utilize rubber hydrocarbon was determined. It was found that the growth of Arthrobacter in both effluent and NRWS was related to pH with the highest growths recorded at pH of 8.5 and 7.5 for effluent and NRWS respectively. It was also found that at controlled pH of 7.5 in NRWS, the growth of Arthrobacter was consistent and was accompanied by a reduction in biological oxygen demand (BOD) which was the the main index for measuring pollution strength of the wastes. It is therefore being recommended that rubber wastes be treated with Arthrobacter under controlled pH to reduce their pollution potentials before disposal. It is however suggested that a combined biological treatment using both Arthrobacter and Mucor as was earlier suggested be used. It is also recommended that chemical flocculants should be used to remove suspended solids in the effluent. A combination of these two cheap methods will go a long way in alleviating the problems of pollution caused by rubber effluents from some tropical rubber processing factories.  相似文献   
192.
Although deforestation and forest degradation have long been considered the most significant threats to tropical biodiversity, across Southeast Asia (Northeast India, Indochina, Sundaland, Philippines) substantial areas of natural habitat have few wild animals (>1 kg), bar a few hunting‐tolerant species. To document hunting impacts on vertebrate populations regionally, we conducted an extensive literature review, including papers in local journals and reports of governmental and nongovernmental agencies. Evidence from multiple sites indicated animal populations declined precipitously across the region since approximately 1980, and many species are now extirpated from substantial portions of their former ranges. Hunting is by far the greatest immediate threat to the survival of most of the region's endangered vertebrates. Causes of recent overhunting include improved access to forests and markets, improved hunting technology, and escalating demand for wild meat, wildlife‐derived medicinal products, and wild animals as pets. Although hunters often take common species, such as pigs or rats, for their own consumption, they take rarer species opportunistically and sell surplus meat and commercially valuable products. There is also widespread targeted hunting of high‐value species. Consequently, as currently practiced, hunting cannot be considered sustainable anywhere in the region, and in most places enforcement of protected‐area and protected‐species legislation is weak. The international community's focus on cross‐border trade fails to address overexploitation of wildlife because hunting and the sale of wild meat is largely a local issue and most of the harvest is consumed in villages, rural towns, and nearby cities. In addition to improved enforcement, efforts to engage hunters and manage wildlife populations through sustainable hunting practices are urgently needed. Unless there is a step change in efforts to reduce wildlife exploitation to sustainable levels, the region will likely lose most of its iconic species, and many others besides, within the next few years.  相似文献   
193.
Pollution of water resources by phosphorus (P) is a critical issue in regions with agricultural and urban development. In this study, we estimated P inputs from agricultural and urban sources in 24 catchments draining to the Central Valley in California and compared them with measured river P export to investigate hydrologic and anthropogenic factors affecting regional P retention and export. Using spatially explicit information on fertilizer use, livestock population, agricultural production, and human population, we calculated that net surface balances for anthropogenic P ranged from -12 to 648 kg P km yr in the early 2000s. Inorganic P fertilizer and manure P comprised the largest fraction of total input for all but two catchments. From 2000 to 2003, a median of 7% (range, -287 to 88%) of net annual anthropogenic P input was exported as total P (TP). Yields (kg P km yr) of dissolved inorganic P (DIP), dissolved organic P, particulate P, and TP were not significantly related to catchment-level, per area anthropogenic P input. However, there were significant relationships between mean annual P concentrations and P input from inorganic fertilizers and manure due to the concentration of agricultural land near catchment mouths and regional variation in runoff. Catchment-level P fertilizer and manure inputs explained 4 to 23% more variance in mean annual DIP and TP concentrations than percent of catchment area in agriculture. This study suggests that spatially explicit estimates of anthropogenic P input can help identify sources of multiple forms of P exported in rivers at management-relevant spatial scales.  相似文献   
194.
Wildfires commonly result in an increase in stream turbidity. However, the influence of pre-fire land-use practices on post-fire stream turbidity is not well understood. The Lower Cotter Catchment (LCC) in south-eastern Australia is part of the main water supply catchment for Canberra with land in the catchment historically managed for a mix of conservation (native eucalypt forest) and pine (Pinus radiata) plantation. In January 2003, wildfires burned almost all of the native and pine forests in the LCC. A study was established in 2005 to determine stream post-fire turbidity recovery within the native and pine forest areas of the catchment. Turbidity data loggers were deployed in two creeks within burned native forest and burned pine forest areas to determine turbidity response to fire in these areas. As a part of the study, we also determined changes in bare soil in the native and pine forest areas since the fire. The results suggest that the time, it takes turbidity levels to decrease following wildfire, is dependent upon the preceding land-use. In the LCC, turbidity levels decreased more rapidly in areas previously with native vegetation compared to areas which were previously used for pine forestry. This is likely because of a higher percentage of bare soil areas for a longer period of time in the ex-pine forest estate and instream stores of fine sediment from catchment erosion during post-fire storm events. The results of our study show that the previous land-use may exert considerable control over on-going turbidity levels following a wildfire.  相似文献   
195.
Sustainable management of landscapes with multiple competing demands such as the Ruaha Landscape is complex due to the diverse preferences and needs of stakeholder groups involved. This study uses conjoint analysis to assess the preferences of representatives from three stakeholder groups—local communities, district government officials, and non-governmental organizations—toward potential solutions of conservation and development tradeoffs facing local communities in the Ruaha Landscape of Tanzania. Results demonstrate that there is little consensus among stakeholders about the best development strategies for the Ruaha region. This analysis suggests a need for incorporating issues deemed important by these various groups into a development strategy that aims to promote conservation of the Ruaha Landscape and improve the livelihood of local communities.  相似文献   
196.
The effectiveness and integrity of forest-based emissions reduction schemes such as Clean Development Mechanism Afforestation Reforestation (CDM A R) project and Reducing Emissions from Deforestation and Degradation (REDD+), along with conservation and enhancement of carbon (C) stocks implementation and assessment in developing countries are required not only, the appropriate monitoring and evaluation, rather the precise values of constants being used to estimate the C stocks or C credit in place of default or guess value. Estimates are reported of the C content of wood of four forest species (Shorea robusta, Pinus roxburghii, Tectona grandis and Cinnamomum camphora) and two important farm species (Populus deltoides and Eucalyptus treticornis) in the temperate region of Indian Himalayas, derived using the ash content method. These species were considered keeping in view of their potentiality for the C sequestration and storage projects across the developing countries specifically the South East Asian Countries. The specific gravity, ash content and C proportion is estimated for these six species by selecting random woods pieces. These estimates are designed to improve the calculations of biomass C for use in estimation of C credits in the developing region under CDM A R projects and REDD+ program supported by developed country. Regression analysis of C prediction models revealed that, for all six species, C content may be estimated through specific gravity of the wood by a linear equation without intercept. Indirectly, this results also implies that among the two farm trees, eucalyptus has high potentiality for C capturing and among four forest trees, Shorea robusta has high potentiality, therefore these two should have preference for plantation/regeneration as well as for conservation.  相似文献   
197.
Environmental radionuclides can be employed as tracers of sediment movement and delivery to water bodies such as lakes and reservoirs. The chronologies of sediments that have accumulated in the Cordeaux reservoir in Sydney, Australia, were determined by the rate of change of (210)Pb(ex) with depth and indicate slow accretion in the reservoir. The ratio of enrichment of radionuclides in sediment cores to (210)Pb(ex) and (137)Cs concentrations in a reference soil sample within the Cordeaux catchment indicates that the dominant source of sediment in the Cordeaux reservoir is surface erosion (detachment and removal of sediment at depths less than 30 cm). However, in the Kembla Creek arm of the reservoir a mixture of sources was detected and includes sheet and rill erosion together with sub-soil contributions. Implications for the utility of these radionuclide sedimentation assessments, especially where samples are limited, are that well-constrained chronologies and sources of soil erosion are facilitated.  相似文献   
198.
Renewable electricity policies promote investment in renewable electricity generators and have become increasingly common around the world. Because of intermittency and the composition of other generators in the power system, the value of certain renewable – particularly wind and solar – varies across locations and technologies. This paper investigates the implications of this heterogeneity for the cost effectiveness of renewable electricity policies. A simple model of the power system shows that renewable electricity policies cause different investment mixes. Policies also differ according to their effect on electricity prices, and both factors cause the cost effectiveness to vary across policies. We use a detailed, long-run planning model that accounts for intermittency on an hourly basis to compare the cost effectiveness for a range of policies and alternative parameter assumptions. The differences in cost effectiveness are economically significant, where broader policies, such as an emissions price, outperform renewable electricity policies.  相似文献   
199.
The use of landholder typologies to aid the development, implementation, and monitoring natural-resource management (NRM) policies and programs has increased considerably during the past decade. This article explores the potential for using such typologies for a variety of NRM and rural and regional development applications. Review of typology use further suggests that there is potential to refine the way that typologies are developed and applied to better aid NRM, farming systems analyses, and rural and regional development. Before typologies will be adopted more widely, a number of theoretical and methodologic issues must be addressed. These include the following questions: (1) Which criteria and methods should or can be used to classify landholders? (2) How should studies across spatial and temporal scales be integrated? (3) How should multiple and single industry studies be integrated to gain the most value from research? We argue that quantitative research techniques are well suited to provide an underlying structure for landholder typologies, and qualitative research techniques are useful for developing understanding of the nature of variation within and between landholder types. We argued further that because of the potential utility and breadth for the application of landholder typologies, a nested set of landholder typologies could be developed that are coordinated at the national, regional, and local geographic levels, with repeated measures used to track the evolution with time of landholder practices, management values, and socioeconomic characteristics.  相似文献   
200.
This paper analyzes the distribution of benefits from an air pollution control strategy for the Boston metropolitan area. Average benefits to seven income groups are measured by physical improvements in air quality and by dollar values, using housing value and health damage approaches to estimate willingness to pay. Benefits include those in the work environment as well as at home. Physical benefits at home are found to be greater for the poor rather than for the rich; when measured in monetary terms with workplace benefits included, however, the distribution is much less pro-poor.  相似文献   
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