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371.
In situ chemical fixation represents a promising and potentially cost‐effective treatment alternative for metal‐contaminated soils. This article presents the findings of the use of iron‐bearing soil amendments to reduce the leachability and bioaccessibility of arsenic in soils impacted by stack fallout from a zinc smelter. The focus of this investigation was to reduce the lead bioaccessibility of the soils through addition with phosphorus‐bearing amendments. However, as phosphorus addition was expected to increase arsenic mobility, the fixation strategy also incorporated use of iron‐bearing amendments to offset or reverse these effects. The findings of this investigation demonstrated that inclusion of iron‐bearing chemicals in the amendment formulation reduced arsenic leachability and bioaccessibility without compromising amendment effectiveness for reducing lead bioaccessibility. These results suggest that in situ chemical fixation has the potential to be an effective strategy for treatment of the impacted soils. © 2003 Wiley Periodicals, Inc. 相似文献
372.
This article examines the role of economic development agencies in strengthening the environmental performance of industry within rapidly industrialising East Asian economies. Three case-study examples are considered, namely, the role of the Industrial Development Board in reducing industrial pollution in Taiwan, pollution control in the palm oil industry in Malaysia, and the role of the Economic Development Board in influencing environmental performance of industry in Singapore. The concept of embedded autonomy is developed to consider the ways in which agencies of economic development can work with firms and industries while simultaneously remaining autonomous from these firms with respect to setting and enforcing performance standards. The three cases suggest that a form of policy integration that more directly integrates economic and environmental goals within agencies of economic development may be feasible, but only where there exists a strong autonomous government bureaucracy and where there is strong societal commitment to improving the environmental performance of industry. 相似文献
373.
There is a growing recognition that knowledge of indigenous communities, based on accumulated observations and experience over time, is significant for sustainable environmental management in collaboration with modern scientific knowledge. A number of innovative policy initiatives are currently being implemented in New Zealand to enable indigenous Maori tribes and sub-tribes to rehabilitate and manage their local fisheries in accordance with customary values and practices. These policies are an important milestone from an historical perspective as they are meant to recognise and empower the role of Maori as Treaty partners. The fisheries management regime in New Zealand now provides for Maori representation at the local level within a co-management framework that enables local Maori communities to exercise their customary rights. These institutional arrangements have been crafted to facilitate Maori input, based on customary values and practices, to complement modern Western management practices for sustainable harvesting of marine resources. Nevertheless, the degree to which these initiatives constitute an adequate response to Maori Treaty aspirations is debatable. A major constraint in this respect is that the government is compelled to recognise the needs of other, economically and politically more dominant, non-Maori user-groups in allocating and managing access to fishery resources and the marine environment. 相似文献
374.
V. Krishna Prasad K.V.S. Badarinath H. Tsuruta S. Sudo S. Yonemura John Cardina Benjamin Stinner Richard Moore Deborah Stinner Casey Hoy 《The Environmentalist》2003,23(2):175-187
Forests and soils are a major sink of carbon, and land use changes can affect the magnitude of above ground and below ground carbon stores and the net flux of carbon between the land and the atmosphere. Studies on methods for examining the future consequences of changes in patterns of land use change and carbon flux gains importance, as they provide different options for CO2 mitigation strategies. In this study, a simulation approach combining Markov chain processes and carbon pools for forests and soils has been implemented to study the carbon flows over a period of time. Markov chains have been computed by converting the land use change and forestry data of India from 1997 to 1999 into a matrix of conditional probabilities reflecting the changes from one class at time t to another class time t+1. Results from Markov modeling suggested Indian forests as a potential sink for 0.94 Gt carbon, with an increase in dense forest area of about 75.93 Mha and decrease of about 3.4 Mha and 5.0 Mha in open and scrub forests, if similar land use changes that occurred during 1997–1999 would continue. The limiting probabilities suggested 34.27 percent as dense forest, 6.90 as open forest, 0.4 percent mangrove forest, 0.1 percent scrub and 58 percent as non-forest area. Although Indian forests are found to be a potential carbon sink, analysis of results from transition probabilities for different years till 2050 suggests that, the forests will continue to be a source of about 20.59 MtC to the atmosphere. The implications of these results in the context of increasing anthropogenic pressure on open and scrub forests and their contribution to carbon source from land use change and forestry sector are discussed. Some of the mitigation aspects to reduce greenhouse gas emissions from land use change and forestry sector in India are also reviewed in the study. 相似文献
375.
ERIC N. POWELL JOHN M. KLINCK EILEEN E. HOFMANN MARGARET A. McMANUS 《Environmental management》2003,31(1):0100-0121
A hydrodynamic–oyster population model was developed to assess the effect of changes in freshwater inflow on oyster populations
in Galveston Bay, Texas, USA. The population model includes the effects of environmental conditions, predators, and the oyster
parasite, Perkinsus marinus, on oyster populations. The hydrodynamic model includes the effects of wind stress, river runoff, tides, and oceanic exchange
on the circulation of the bay. Simulations were run for low, mean, and high freshwater inflow conditions under the present
(1993) hydrology and predicted hydrologies for 2024 and 2049 that include both changes in total freshwater inflow and diversions
of freshwater from one primary drainage basin to another.
Freshwater diversion to supply the Houston metropolitan area is predicted to negatively impact oyster production in Galveston
Bay. Fecundity and larval survivorship both decline. Mortality from Perkinsus marinus increases, but to a lesser extent. A larger negative impact in 2049 relative to 2024 originates from the larger drop in fecundity
under that hydrology. Changes in recruitment and mortality, resulting in lowered oyster abundance, occur because the bay volume
available for mixing freshwater input from the San Jacinto and Buffalo Bayou drainage basins that drain metropolitan Houston
is small in comparison to the volume of Trinity Bay that presently receives the bulk of the bay's freshwater inflow. A smaller
volume for mixing results in salinities that decline more rapidly and to a greater extent under conditions of high freshwater
discharge.
Thus, the decline in oyster abundance results from a disequilibrium between geography and salinity brought about by freshwater
diversion. Although the bay hydrology shifts, available hard substrate does not. The simulations stress the fact that it is
not just the well-appreciated reduction in freshwater inflow that can result in decreased oyster production. Changing the
location of freshwater inflow can also significantly impact the bay environment, even if the total amount of freshwater inflow
does not change. 相似文献
376.
James V. Bonta Bruce Cleland 《Journal of the American Water Resources Association》2003,39(6):1481-1496
ABSTRACT: Quantifying natural variability, uncertainty, and risk with minimal data is one of the greatest challenges facing those engaged in water quality evaluations, such as development of total maximum daily loads (TMDL), because of regulatory, natural, and analytical constraints. Quantification of uncertainty and variability in natural systems is illustrated using duration curves (DCs), plots that illustrate the percent of time that a particular flow rate (FDC), concentration (CDC), or load rate (LDC; “TMDL”) is exceeded, and are constructed using simple derived distributions. Duration curves require different construction methods and interpretations, depending on whether there is a statistically significant correlation between concentration (C) and flow (Q), and on the sign of the C‐Q regression slope (positive or negative). Flow DCs computed from annual runoff data vary compared with an FDC developed using all data. Percent exceedance for DCs can correspond to risk; however, DCs are not composed of independent quantities. Confidence intervals of data about a regression line can be used to develop confidence limits for the CDC and LDC. An alternate expression to a fixed TMDL is suggested as the risk of a load rate being exceeded and lying between confidence limits. Averages over partial ranges of DCs are also suggested as an alternative expression of TMDLs. DCs can be used to quantify watershed response in terms of changes in exceedances, concentrations, and load rates after implementation of best management practices. 相似文献
377.
Gary O. Graening Arthur V. Brown 《Journal of the American Water Resources Association》2003,39(6):1497-1507
ABSTRACT: Subterranean ecosystems harbor globally rare fauna and important water resources, but ecological processes are poorly understood and are threatened by anthropogenic stresses. Ecosystem analyses were conducted from 1997 to 2000 in Cave Springs Cave, Arkansas, situated in a region of intensive land use, to determine the degree of habitat degradation and viability of endangered fauna. Organic matter budgeting quantified energy flux and documented the dominant input as dissolved organic matter and not gray bat guano (Myotis grisescens). Carbon/nitrogen stable isotope analyses described a trophic web of Ozark cavefish (Amblyopsis rosae) that primarily consumed cave isopods (Caecidotea stiladactyla), which in turn appeared to consume benthic matter originating from a complex mixture of soil, leaf litter, and anthropogenic wastes. Septic leachate, sewage sludge, and cow manure were suspected to augment the food web and were implicated in environmental degradation. Water, sediment, and animal tissue analyses detected excess nutrients, fecal bacteria, and toxic concentrations of metals. Community assemblage may have been altered: sensitive species‐grotto salamanders (Typhlotriton spelaeus) and stygobro‐mid amphipods—were not detected, while more resilient isopods flourished. Reduction of septic and agricultural waste inputs may be necessary to restore ecosystem dynamics in this cave ecosystem to its former undisturbed condition. 相似文献
378.
J. Y. Kim M.-C. Shin J.-R. Park K. Nam 《Journal of Material Cycles and Waste Management》2003,5(1):0055-0062
The effect of the soil solids concentration in batch tests on the measured values of the partition coefficient (K
p) of organic pollutants in landfill liner-soil material was investigated. Since this study was based on the results of batch
and column tests conducted independently, there were limitations to the conclusions derived. The organic compounds tested
were benzene, methylene chloride, toluene, trichloroethylene, and p-xylene. The results of this study showed that as soil solids concentrations increased, the measured K
p values of these organic compounds strongly decreased. The observed values of K
p stabilized when the soil solids concentration was above a certain value. Typical K
p values obtained from batch tests conducted under high soil solids concentrations were close to those obtained from column
tests. It was concluded that the K
p values of organic compounds measured under low soil solids concentrations, i.e., less than 100 g/l, may not correctly simulate
the field situation. Consequently, the values of K
p obtained with low soil solids concentrations can result in an overestimation of the retardation factor of the landfill liner
material.
Received: March 14, 2002 / Accepted: August 25, 2002 相似文献
379.
H. Ozaki K. Sharma C. Phanuwan K. Fukushi C. Polprasert 《Journal of Material Cycles and Waste Management》2003,5(1):0031-0038
This paper deals with the present scenario of hazardous waste management practices in Thailand, and gives some insights into
future prospects. Industrialization in Thailand has systematically increased the generation of hazardous waste. The total
hazardous waste generated in 2001 was 1.65 million tons. It is estimated that over 300 million kg/year of hazardous waste
is generated from nonindustrial, community sources (e.g., batteries, fluorescent lamps, cleansing chemicals, pesticides).
No special facilities are available for handling these wastes. There are neither well-established systems for separation,
storage, collection, and transportation, nor the effective enforcement of regulations related to hazardous wastes management
generated from industrial or nonindustrial sectors. Therefore, because of a lack of treatment and disposal facilities, these
wastes find their way into municipal wastewaters, public landfills, nearby dump sites, or waterways, raising serious environmental
concern. Furthermore, Thailand does not have an integrated regulatory framework regarding the monitoring and management of
hazardous materials and wastes. In addition to the absence of a national definition of hazardous wastes, limited funding has
caused significant impediments to the effective management of hazardous waste. Thus, current waste management practices in
Thailand present significant potential hazards to humans and the environment. The challenging issues of hazardous waste management
in Thailand are not only related to a scarcity of financial resources (required for treatment and disposal facilities), but
also to the fact that there has been no development of appropriate technology following the principles of waste minimization
and sustainable development. A holistic approach to achieving effective hazardous waste management that integrates the efforts
of all sectors, government, private, and community, is needed for the betterment of human health and the environment.
Received: February 26, 2001 / Accepted: October 11, 2002 相似文献
380.
S. L. Holmberg T. Claesson M. Abul-Milh B. -M. Steenari 《Resources, Conservation and Recycling》2003,38(4):3071
At the district heating plant of Kalmar, Sweden an on-line unit for production of granulated wood ash for nutrient recycling on forest soils is being applied. Currently, the granules are dried by hot air from an oil-fired burner. The objective of this work was to investigate how drying by flue gas affects the hardening of granules, or impacts their chemical composition and properties. Ninety-six granule samples were treated by flue gas from natural gas combustion in a laboratory pilot scale flue gas generator. CO2, CO, O2, C3H8 and NO concentrations were varied during the experiment. Additionally, some samples were treated by flue gas from combustion of sawdust at the heating plant in Kalmar. Drying by flue gases did not affect the chemical composition of granules, but minor effects were seen in their mineralogy. The carbonate content was slightly higher in granules treated with flue gas from natural gas combustion compared to the granules dried by hot air only, when measured by wet chemical methods. Results from XRD analysis imply that the calcite content is higher and the portlandite and arcanite content slightly less in granules treated with flue gas from sawdust combustion compared to the granules dried by hot air only. The results from this investigation showed no negative effects on ash granule composition or physical structure by the use of a flue as a drying medium. 相似文献