Landfills have been the dominant alternative for disposal of solid waste and there are tens of thousands of closed landfills throughout the world that require a long-term management strategy. In contrast to approaches based on time or target values, this paper describes a performance-based methodology for evaluation of post-closure care (PCC). Using the methodology, critical components of PCC at a landfill, including leachate and gas management, groundwater monitoring and cover integrity, are considered to determine whether a landfill meets defined conditions for functional stability and can transition from regulated PCC to a post-regulatory custodial care program representing de minimus care activities only. The methodology is predicated on understanding the biological, chemical, and physical behavior of a landfill and the presence of sufficient data to verify expected trends in landfill behavior. If an evaluation suggests that a change can be made to PCC, the landfill owner must perform confirmation monitoring and then surveillance monitoring at a decreasing frequency to verify that the change is protective of human health and the environment. A hypothetical case study showed that using the methodology to evaluate site-specific PCC requirements could result in increased environmental protection at comparable cost by spending available funds where they are most needed. 相似文献
Objective: This study used medico-legal data to investigate fatal older road user (ORU, aged 65 years and older) crash circumstances and risk factors relating to 4 key components of the Safe System approach (e.g., roads and roadsides, vehicles, road users, and speeds) to identify areas of priority for targeted prevention activity.
Method: The Coroners' Court of Victoria's (CCOV) Surveillance Database was searched to identify and describe the frequency and rate per 100,000 population of fatal ORU crashes in the Australian state of Victoria for 2013–2014. Information relating to the deceased ORU, crash characteristics and circumstances, and risk factors was extracted and analyzed.
Results: One hundred and thirty-eight unintentional fatal ORU crashes were identified in the CCOV Surveillance Database. Of these fatal ORU crashes, most involved older drivers (44%), followed by older pedestrians (32%), older passengers (17%), older pedal cyclists (4%), older motorcyclists (1%), and older mobility scooter users (1%). The average annual rate of fatal ORU crashes per 100,000 population was 8.1 (95% confidence interval [CI], 6.0–10.2). In terms of the crash characteristics and circumstances, most fatal ORU crashes involved a counterpart (98%), of which the majority were passenger cars (50%) or fixed/stationary objects (25%), including trees (46%) or embankments (23%). In addition, most fatal ORU crashes occurred close to home (73%), on-road (87%), on roads that were paved (94%), on roads with light traffic volume (37%), and during low-risk conditions: between 12 p.m. and 6 p.m. (44%), on weekdays (80%), during daylight (75%), and under dry/clear conditions (81%). Road user (RU) error was identified by the police and/or the coroner for the majority of fatal crashes (55%), with a significant proportion of deceased ORUs deemed to have failed to yield (54%) or misjudged (41%).
Conclusions: RU error was the most significant factor identified in fatal ORU crashes, which suggests that there is a limited capacity of the road system to fully accommodate RU errors. Initiatives related to safer roads and roadsides, vehicles, speed zones, as well as behavioral approaches are key areas of priority for targeted activity to prevent fatal ORU crashes in the future. 相似文献
There is now an emerging sense of the scope and nature of response that can be implemented at building and neighbourhood scales to help adapt cities and urban areas to the changing climate. In comparison, the role of larger natural and semi-natural landscapes that surround and permeate cities is less well understood. Addressing this knowledge gap, this paper outlines two case studies that describe and map the flood risk management functions offered by green infrastructure landscapes situated within the Urban Mersey Basin in North West England. The case studies establish that areas potentially exposed to flooding can be located at some distance, and within different jurisdictions, from upstream areas where the flood hazard may be generated and could be moderated via functions provided by green infrastructure landscapes. This raises planning and governance challenges connected to supporting and enhancing flood risk management functions provided by green infrastructure landscapes. 相似文献
The purpose of this paper is to identify the atmospheric conditions associated with elevated ground-level ozone concentrations during June–August of 2000–2007 at 11 ozone-monitoring stations in the Atlanta, GA, USA metropolitan statistical area (MSA). Analyses were confined to high-ozone days (HODs), which had a daily maximum 8-h average ozone concentration in the 95th percentile of all June–August values. Therefore, each station had 36 HODs. The southeastern and far northern portions of the MSA had HODs with the highest and lowest ozone concentrations, respectively. HODs at nearly all Atlanta MSA ozone-monitoring stations were enabled by migratory anticyclones. HODs for most stations were hot, dry, and calm with low morning mixing heights and high afternoon mixing heights. All sets of HODs had daily mean relative humidities and afternoon mixing heights that, respectively, were significantly less than and significantly greater than mean values for the remaining days. Urbanized Atlanta typically was upwind of an ozone-monitoring station on its HODs; therefore, wind direction on HODs varied considerably among the stations. HODs may have been caused partially by NOx emissions from electric-utility power plants: HODs in the southern portion of the MSA were linked to air-parcel trajectories intersecting a power plant slightly northwest of Atlanta and plants in the Ohio River Valley, while HODs in the northern portion of the MSA were linked to air-parcel trajectories intersecting two large power plants slightly southeast of the Atlanta MSA. Results from this study suggest that future research in the Atlanta MSA should focus on power-plant contributions to ground-level ozone concentrations as well as the identification of non-monitored locations with potentially high ozone concentrations. 相似文献
Sustainability research is expected to incorporate concepts, methods, and data from a diverse array of academic disciplines.
We investigate the extent to which sustainability research lives up to this ideal of an interdisciplinary field. Using bibliometric
data, we orient our study around the “tripartite model” of sustainability, which suggests that sustainability research should
draw from the three “pillars” of the environmental, economic, and social sciences. We ask three questions: (i) is sustainability
research truly more interdisciplinary than research generally, (ii) to what extent does research grounded in one pillar draw
on research from the other two, and (iii) if certain disciplines or pillars are more interdisciplinary than others, then what
explains this variation? Our results indicate that sustainability science, while more interdisciplinary than other scientific
fields, falls short of the expectations inherent in the tripartite model. The pillar with the fewest articles published on
sustainability—economics—is also the most integrative, while the pillar with the most articles—environmental sciences—draws
the least from outside disciplines. But interdisciplinarity comes at a cost: sustainability research in economics and the
social sciences is centered around a relatively small number of interdisciplinary journals, which may be becoming less valued
over time. These findings suggest that, if sustainability research is to live up to its interdisciplinary ideals, researchers
must be provided with greater incentives to draw from fields other than their own. 相似文献
A titrimetric method is described for the analysis of sulfate in lead dioxide candles which have been exposed to atmospheric sulfur pollution. The time taken to analyse one sample is 3 hr. Sixty milliliters of 8% ammonium carbonate solution is used to convert the lead sulfate present on the candle to ammonium sulfate. The solution is filtered lc remove lead dioxide, and an aliquot of the filtrate is heated to remove ammonium carbonate. The solution of ammonium sulfate remaining is titrated directly for sulfate with 0.02 M barium perchlorate, using Thoron as indicator. The accuracy of the method is ±10 and ±6 % of theoretical, for 10 mg, and 40 mg or greater amounts of sulfate, respectively. For 2 mg of sulfate, results are about 20% high. Good agreement has been obtained between results for duplicate field candles, analyzed by the standard sodium carbonate gravimetric method, and the method presented, over a five-month period. 相似文献
The approach of this paper is to predict the sand mass distribution in an urban stormwater holding pond at the Stormwater Management And Road Tunnel (SMART) Control Centre, Malaysia, using simulated depth average floodwater velocity diverted into the holding during storm events. Discriminant analysis (DA) was applied to derive the classification function to spatially distinguish areas of relatively high and low sand mass compositions based on the simulated water velocity variations at corresponding locations of gravimetrically measured sand mass composition of surface sediment samples. Three inflow parameter values, 16, 40 and 80 m3 s?1, representing diverted floodwater discharge for three storm event conditions were fixed as input parameters of the hydrodynamic model. The sand (grain size?>?0.063 mm) mass composition of the surface sediment measured at 29 sampling locations ranges from 3.7 to 45.5 %. The sampling locations of the surface sediment were spatially clustered into two groups based on the sand mass composition. The sand mass composition of group 1 is relatively lower (3.69 to 12.20 %) compared to group 2 (16.90 to 45.55 %). Two Fisher’s linear discriminant functions, F1 and F2, were generated to predict areas; both consist of relatively higher and lower sand mass compositions based on the relationship between the simulated flow velocity and the measured surface sand composition at corresponding sampling locations. F1?=??9.405?+?4232.119?×?A???1795.805?×?B?+?281.224?×?C, and F2?=??2.842?+?2725.137?×?A???1307.688?×?B?+?231.353?×?C. A, B and C represent the simulated flow velocity generated by inflow parameter values of 16, 40 and 80 m3 s?1, respectively. The model correctly predicts 88.9 and 100.0 % of sampling locations consisting of relatively high and low sand mass percentages, respectively, with the cross-validated classification showing that, overall, 82.8 % are correctly classified. The model predicts that 31.4 % of the model domain areas consist of high-sand mass composition areas and the remaining 68.6 % comprise low-sand mass composition areas. 相似文献
Sexual size dimorphism, in which one sex is larger than the other, occurs when body size has differential effects on the fitness
of males and females. Mammals and birds usually have male-biased size dimorphism, probably because of strong sexual competition
among males. Invertebrates usually have female-biased size dimorphism, perhaps because their inflexible exoskeletons limit
ovary size, leading to a strong correlation between female body size and fecundity. In this paper, we test whether an additional
factor, the type of parental care provided, affects the degree of sexual size dimorphism. Among wasps and bees, there is a
contrast between provisioning taxa, in which females must gather and transport heavy loads of provisions to nests they have
constructed, and non-provisioning taxa, in which females lay eggs but do not construct nests or transport provisions. Males
have no role in parental care in either case. An analysis of British wasps and bees shows that provisioning taxa have significantly
more female-biased size dimorphism than non-provisioning taxa. This is true for simple cross‑species comparisons and after
controlling for phylogeny. Our data imply that the demands of carrying provision loads are at least part of the explanation
for this pattern. Thus, sexual size dimorphism is greatest in pompilid wasps, which carry the heaviest prey items. Bees, which
transport minute pollen grains, exhibit the least dimorphism. We also find that cavity‑nesting species, in which nest construction
costs may be minimized, exhibit reduced dimorphism, but this was not significant after controlling for phylogeny. 相似文献