ABSTRACT: The Cheat River of West Virginia is impaired by acid mine drainage (AMD). Fifty‐five of its river segments were placed on the 303(d) list, which required calculations of total maximum daily load (TMDL) to meet the water quality criteria for pH, total iron, aluminum, manganese, and zinc. An existing watershed model was enhanced to simulate AMD as nonpoint source load. The model divided a watershed into a network of catchments and river segments. Each catchment was divided into soil layers, which could contain pyrite, calcite and other minerals. A kinetic expression was used to simulate pyrite oxidation as a function of oxygen in the soil voids. Oxygen in the soil voids was consumed by pyrite oxidation and replenished by earth breathing. The by‐products of pyrite oxidation were calculated according to its mass action equations. Chemical equilibrium was used to account for the speciation of ferrous and ferric irons and precipitation of metal hydroxides. Simulated hydrology and water quality were compared to available data. The USEPA used the calibrated model to calculate the TMDLs in the Cheat River Watershed. 相似文献
Extreme weather and climate-related events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future. Some of these events include heat waves, droughts, wildfires, dust storms, flooding rains, coastal flooding, storm surges, and hurricanes. The pathways connecting extreme events to health outcomes and economic losses can be diverse and complex. The difficulty in predicting these relationships comes from the local societal and environmental factors that affect disease burden. More information is needed about the impacts of climate change on public health and economies to effectively plan for and adapt to climate change. This paper describes some of the ways extreme events are changing and provides examples of the potential impacts on human health and infrastructure. It also identifies key research gaps to be addressed to improve the resilience of public health to extreme events in the future.
Implications: Extreme weather and climate events affect human health by causing death, injury, and illness, as well as having large socioeconomic impacts. Climate change has caused changes in extreme event frequency, intensity, and geographic distribution, and will continue to be a driver for change in the future. Some of these events include heat waves, droughts, wildfires, flooding rains, coastal flooding, surges, and hurricanes. The pathways connecting extreme events to health outcomes and economic losses can be diverse and complex. The difficulty in predicting these relationships comes from the local societal and environmental factors that affect disease burden. 相似文献
Based on the national database of 28,104 water rights (concessions) granted in Colombia, this paper presents an analysis of how the principles of equity and sustainability are reflected in water allocation. Concessions appear to be an exclusionary mechanism since only a minority of small water users have concessions and the distribution of water volumes among those who have them is extremely inequitable. The 2009 Gini coefficient calculated for water concessions granted for agriculture was 0.90 compared with the rural land Gini of 0.88 (both indicators grouping holdings under the same entity). More than half of the Colombian departments have a higher Gini coefficient for water than for land, suggesting that water rights are at least as unequally distributed as land, in one of the most inequitable countries in Latin America. Water allocated to domestic, agriculture and hydropower use indicates a lack of consistency of water allocation criteria across regions. The volumetric and administrative attributes of water allocation in Colombia do not account for environmental flows or the concerns of marginalised groups of society that have limited access to the mechanism. Water allocation as a technical task, with limited transparency and secluded from public scrutiny, does not contribute to the solution of increasing water-related conflicts. 相似文献
The ethnically diverse high-altitude region of Gilgit-Baltistan, with its complex political history, remains relatively free from the controlling gaze of the central state apparatus of Pakistan. In these extraordinary terrain, where local communities rule the region as the “State by proxy”, informal gemstone mining provides an important supplement to livelihoods. This paper shows that gemstone mining in Gilgit-Baltistan is characterised by customary rules and regulations that are based on collective responsibility, and members follow customary authorities because they are not external to the community. It argues that the very idea of centralised “governance” of mineral resources, used widely in contexts of resource extraction as the panacea, needs to be reconsidered when dealing with the particularities of the context. It draws on the concept of ungovernability to underline the fact that sometimes it may simply be impossible to administer informal mining in the conventional sense of the term. It suggests in conclusion that informal mining, which has a long history in Pakistan and has played an increasing role as a source of rural employment and revenue, needs to be accommodated within the legal framework of mining. More importantly, to govern informal mining of gemstones, the first task would be to consider how things are currently done, understanding and respecting customary laws, and build upon them to incorporate their elements into systems that acknowledge community rights and a more equitable sharing of benefits. 相似文献
The US National Cancer Institute's natural products collection program has been running since 1986 and over the years the materials collected and processed have been stored in a repository that as a result of initial planning, has permitted the establishment of a national resource that is now being utilized as a drug discovery tool for any disease of interest to the NIH by researchers world-wide. This paper describes the history of the program. 相似文献
Dimethyl sulphide (DMS) and carbon monoxide (CO) are climate-relevant trace gases that play key roles in the radiative budget of the Arctic atmosphere. Under global warming, Arctic sea ice retreats at an unprecedented rate, altering light penetration and biological communities, and potentially affect DMS and CO cycling in the Arctic Ocean. This could have socio-economic implications in and beyond the Arctic region. However, little is known about CO production pathways and emissions in this region and the future development of DMS and CO cycling. Here we summarize the current understanding and assess potential future changes of DMS and CO cycling in relation to changes in sea ice coverage, light penetration, bacterial and microalgal communities, pH and physical properties. We suggest that production of DMS and CO might increase with ice melting, increasing light availability and shifting phytoplankton community. Among others, policy measures should facilitate large-scale process studies, coordinated long term observations and modelling efforts to improve our current understanding of the cycling and emissions of DMS and CO in the Arctic Ocean and of global consequences. 相似文献
Human activities are changing the Arctic environment at an unprecedented rate resulting in rapid warming, freshening, sea ice retreat and ocean acidification of the Arctic Ocean. Trace gases such as nitrous oxide (N2O) and methane (CH4) play important roles in both the atmospheric reactivity and radiative budget of the Arctic and thus have a high potential to influence the region’s climate. However, little is known about how these rapid physical and chemical changes will impact the emissions of major climate-relevant trace gases from the Arctic Ocean. The combined consequences of these stressors present a complex combination of environmental changes which might impact on trace gas production and their subsequent release to the Arctic atmosphere. Here we present our current understanding of nitrous oxide and methane cycling in the Arctic Ocean and its relevance for regional and global atmosphere and climate and offer our thoughts on how this might change over coming decades.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01633-8. 相似文献
Abstract: A stream mesocosm experiment was conducted to study the ecosystem‐wide effects of two replicated flow hydrograph treatments programmed in an attempt to compare a simulated predevelopment condition to the theoretical changes that new development brings, while accounting for engineering design criteria for urban stormwater management. Accordingly, the treatments (three replicates each) differed in base flow between events and in the rise to, fall from, and duration of peak flow during simulated storm hydrographs, which were triggered by real rain events occurring outside over a 96‐day period from summer to fall, 2005. Incident irradiance, initial substrate quality, and water quality were similar between treatments. Sampling was designed to study the interactions among the treatment flow dynamics, sediment transport processes, streambed nutrients, and biotic structure and function. What appeared most important to the overall structure and function of the mesocosm ecosystems beyond those changes resulting from natural seasonality were (1) the initial mass of fines that infiltrated into the gravel bed, which had a persistent effect on nitrogen biogeochemistry and (2) the subsequent fine sediment accumulation rate, which was unexpectedly similar between treatments, and affected the structure of the macroinvertebrate community equally as the experiment progressed. Invertebrate taxa preferring soft beds dominated when the gravel was comprised of 5‐10% fines. The dominant invertebrate algal grazer had vacated the channels when fines exceeded 15%, but this effect could not be separated from what appeared to be a seasonal decline in insect densities over the course of the study. Neither hydrograph treatment allowed for scour or other potential for flushing of fines. This demonstrated the potential importance of interactions between hydrology and fine sediment loading dynamics on stream ecosystems in the absence of flows that would act to mobilize gravel beds. 相似文献
This paper explores issues of governance and decision-making structures associated with the problem of hexachlorobenzene (HCB) waste at Botany in New South Wales. From a government perspective, the problem is ‘downstream’ of a well-known national controversy over whether Australia should have a high-temperature incinerator (HTI) to ‘dispose’ of such scheduled wastes. The 1992 decision not to proceed with HTI followed an extensive process of public consultation, which, against the expectations of industry and government, saw the emergence of Australia-wide community opposition. Alternative national management plans were formulated for the treatment of several types of organochlorine waste, with the scheme of these plans first approved in 1993 by the Australian and New Zealand Environment and Conservation Council (ANZECC). The HCB Management Plan is one of three such plans (the others being for PCBs and organochlorine pesticides). With this, ANZECC established the Scheduled Waste Management Group comprising government officials, and the National Advisory Body (NAB) made up of stakeholders. Officially the NAB had oversight of the HCB problem until 2002 when it was disbanded. As a result of the HTI experience, new community consultation protocols were introduced in association with the alternative management plans. For HCBs, which are confined almost entirely to Orica's Botany site in southeastern Sydney, this led to the establishment of the Community Participation and Review Committee (CPRC), a representative body with review and advisory functions. This paper draws conclusions from this history about government processes of decision making, the role of individual and institutional actors, the central importance of trust, and the democratisation of risk management. Using concepts delineated by McDonell [1991. Toxic waste management in Australia: why did policy reform fail? Environment 33(6), 11–13, 33–39; 1997. Scientific and everyday knowledge: trust and the politics of environmental initiatives. Social Studies of Science 27, 819–863.] we identify swings towards, then away from institutionalised trust. Across two decades, government and industry have placed faith in centrally controlled mechanisms for public participation, hoping to garner trust and legitimate privileged technological solutions. On the ‘backswings’, these processes have seen public trust dissipate in the face of government misunderstanding of the opportunities for effective bureaucratic interventions. 相似文献
Despite strong longitudinal associations between particle personal exposures and ambient concentrations, previous studies have found considerable inter-personal variability in these associations. Factors contributing to this inter-personal variability are important to identify in order to improve our ability to assess particulate exposures for individuals. This paper examines whether ambient, home outdoor and home indoor particle concentrations can be used as proxies of corresponding personal exposures. We explore the strength of the associations between personal, home indoor, home outdoor and central outdoor monitoring site ("ambient site") concentrations of sulfate, fine particle mass (PM(2.5)) and elemental carbon (EC) by season and subject for 25 individuals living in the Boston, MA, USA area. Ambient sulfate concentrations accounted for approximately 70 to 80% of the variability in personal and indoor sulfate levels. Correlations between ambient and personal sulfate, however, varied by subject (0.1-1.0), with associations between personal and outdoor sulfate concentrations generally mirroring personal-ambient associations (median subject-specific correlations of 0.8 to 0.9). Ambient sulfate concentrations are good indicators of personal exposures for individuals living in the Boston area, even though their levels may differ from actual personal exposures. The strong associations for sulfate indicate that ambient concentrations and housing characteristics are the driving factors determining personal sulfate exposures. Ambient PM(2.5) and EC concentrations were more weakly associated with corresponding personal and indoor levels, as compared to sulfate. For EC and PM(2.5), local traffic, indoor sources and/or personal activities can significantly weaken associations with ambient concentrations. Infiltration was shown to impact the ability of ambient concentrations to reflect exposures with higher exposures to particles from ambient sources during summer. In contrast in the winter, lower infiltration can result in a greater contribution of indoor sources to PM(2.5) and EC exposures. Placing EC monitors closer to participants' homes may reduce exposure error in epidemiological studies of traffic-related particles, but this reduction in exposure error may be greater in winter than summer. It should be noted that approximately 20% of the EC data were below the field limit of detection, making it difficult to determine if the weaker associations with the central site for EC were merely a result of methodological limitations. 相似文献