Towards a global historical emission inventory for selected PCB congeners--a mass balance approach 3. An update

Previously published estimates of the global production, consumption and atmospheric emissions of 22 individual PCB congeners [Breivik K, Sweetman A, Pacyna JM, Jones KC. Towards a global historical emission inventory for selected PCB congeners - a mass balance approach. 1. Global production and consumption. Sci Total Environ 2002a; 290: 181-198.; Breivik K, Sweetman A, Pacyna JM, Jones KC. Towards a global historical emission inventory for selected PCB congeners--a mass balance approach. 2. Emissions. Sci Total Environ 2002b; 290: 181-198.] have provided useful information for later studies attempting to interpret contaminant levels in remote areas as well as in the global environment. As a result of the need for more contemporary emission data (following the year 2000), an update of this emission database is presented. This exercise takes into account new information on PCB production in Poland, as well as new data on the chemical composition of various technical mixtures for which less information had been available. The methodology to estimate temporal trends of PCB emissions associated with various types of PCB usage is improved. Projected emissions up to year 2100 are presented to facilitate predictions of future environmental exposure. The national emission data for each of the 114 countries considered is spatially resolved on a 1 degrees x1 degrees grid for each congener and year, using population density as a surrogate.     

Towards a global historical emission inventory for selected PCB congeners--a mass balance approach. 1. Global production and consumption

Information on the historical global production and consumption of polychlorinated biphenyls (PCBs) is urgently needed for estimating PCB fluxes to the environment and for interpreting global contamination patterns by these pollutants. This study presents the methodology, principal uncertainties and selected results from an inventory, aiming to quantify the global production and consumption of total PCBs as well as 22 PCB congeners. The available data on the historical production of PCBs and the chemical composition of various technical mixtures have been compiled from the literature. For some producers with less detailed information, the production of individual PCB constituents has been estimated to derive a global estimate for individual homologues and selected congeners. Information on imports, exports and consumption, as well as restrictions on production and imports, has further been compiled for individual countries. These data, along with assumptions on the trade between countries and regions, have been utilised to derive an estimate of the global historical consumption pattern. Although there are substantial uncertainties involved in these estimates, important aspects governing the large scale temporal and spatial patterns are most likely captured in these estimates. In particular, the information on imports and exports for the principal users of PCBs around the time of peak production is considered to be fairly reliable. The estimates account for a reported historical global production of approximately 1.3 million t PCBs, more than 70% of which are tri-, tetra- and pentachlorinated biphenyls. The results further suggest that almost 97% of the global historical use of PCBs have occurred in the Northern Hemisphere.     

Simple soil mass balance approach to interpret the distribution of global terrestrial gamma ray dose rates in relation to geology

A recent literature survey on natural gamma rays has yielded data on the dose rate levels above soils and rocks in the world, classified by their associated bedrock types. For comparison, the data in the Japanese Islands were also collected. The compiled results indicated a strong linear correlation between the soil and the rock dose rates. A soil-mass balance model was used to obtain the quantitative estimate of soil production and inflow rates, respectively, relative to the outflow rate. It was found from the analysis that the degree of mixing of soils, measured by the ratio between the inflow and the production rates, was fairly small in Japan compared to the world average.     

A prospective atmospheric emission inventory for cadmium--the European community as a study area

The quantities of cadmium emitted to the atmosphere from natural and human sources have been estimated for the member states of the European Community, allowing the construction of an atmospheric emission inventory for cadmium at the regional level. A survey of the available emission data was used to calculate an emission factor (g cadmium emitted tonne -1 material consumed or produced) for each source. This value was applied to the most recent consumption or production data for the region to obtain an annual discharge estimate. Predictions of future trends in cadmium emissions from human sources over the next two decades were based on economic forecasts for the process in question. The iron and steel industries and refuse incineration are the two largest sources of airborne cadmium in the region, followed by volcanic action and zinc production. It is forecast that there will be an increase in cadmium emissions over the next two decades due mainly to the iron and steel industries and zinc production. A comparison of the emission estimates obtained in this study with those given in previously published inventories reveal disparities in the source strengths for some processes. In particular, it would appear that cadmium emissions from coal combustion and non-ferrous metal production have been overestimated in some past studies.     

The joint approach for a global test systems market

Throughout the entire spectrum of the manufacturing industry, the words `globalisation' and `consolidation' have become common currency. Companies and organisations are being forced to operate in increasingly competitive, increasingly global markets against increasingly aggressive world-class players. Through mergers, joint ventures and acquisitions, fewer and larger groups are taking the wider view beyond their immediate domestic markets to win market share in the fastest-growing world economies. Here, the author describes how Instron and Carl Schenck, two key international players in the niche market for materials, products and structures-testing equipment have now formed an alliance aimed at winning a bigger slice of the global cake     

A mass balance approach for evaluating leachable arsenic and chromium from an in-service CCA-treated wood structure

Many existing residential wood structures, such as playsets and decks, have been treated with chromated copper arsenate (CCA). This preservative chemical can be released from these structures incrementally over time through contact with rainfall. The objective of this study was to evaluate the levels of arsenic and chromium leached from an in-service CCA-treated deck exposed to rainfall, as well as their possible impacts on soils and shallow groundwater. Two monitoring stations, one containing a CCA-treated deck and the other containing an untreated deck as a control, were constructed outside for this study. Rainfall, runoff water from the decks, soils below the decks, and infiltrated water through 0.7-m depth of soil were monitored for arsenic and chromium over a period of 3 years. The concentration of the CCA-treated deck runoff for arsenic (0.114-4.66 mg/L) and chromium (0.008-0.470 mg/L) were significantly (p<0.001) higher than the untreated deck runoff (< or =0.002 mg/L for both). During the 3-year monitoring period, 13% of the arsenic and 1.4% of the chromium were leached from the amount initially present in the CCA-treated wood. Arsenic levels (<0.1-46 mg/kg) in soils under the CCA-treated deck were significantly (p<0.001) higher than under the untreated deck (<0.1-2.7 mg/kg), while chromium levels were statistically the same below the two decks (2.4-9.6 mg/kg). Approximately 94% of the arsenic from the runoff was absorbed in the soils below the CCA-treated deck; the upper 2.5 cm of the soils captured 42% of the total. The infiltrated water concentrations for arsenic (<0.001-0.085 mg/L) and chromium (<0.001-0.010 mg/L) below the CCA-treated deck were both significantly (p<0.001) higher than below the untreated deck (< or =0.006 mg/L). The amounts of arsenic found in the infiltrated water below the CCA-treated deck represented 6% of total arsenic leached and less than 0.7% of the initial mass in the wood. The study demonstrated that exposure of a CCA-treated deck to rainfall resulted in elevated arsenic concentrations in both runoff and soil. Although only a relatively small fraction of the initial arsenic from the wood was found to infiltrate through the soil, these impacts were significant and caused the infiltrated water to exceed drinking water standards. The study suggests that potential exposures to arsenic exist indirectly through an environment that is contaminated with arsenic leached from in-service CCA-treated wood.     

Assessment of in vivo bioaccessibility of arsenic in dietary rice by a mass balance approach

A pilot dietary experiment was conducted over 10 days to evaluate whether a simple yet often underutilized approach of constructing mass balance of arsenic metabolites can be used to assess in vivo bioaccessibility of arsenic in cooked rice. Two volunteers were involved in this study. The quantity of drinking water, food and urine samples, together with arsenic concentration and speciation of these samples was monitored to construct a mass balance of arsenic intake and excretion. In the first five days, the two volunteers on a wheat diet had an average arsenic daily intake of 15.4 ± 2.6 µg and 9.6 ± 0.7 µg, respectively. In the next five days, these volunteers switched to a rice diet, increasing the average arsenic daily intake to 36.4 ± 2.8 µg and 34.1 ± 7.7 µg, respectively. Daily excretion of urinary arsenic, mostly as dimethylarsenic acid (DMA), doubled from 9.8 ± 0.3 µg to 21.0 ± 3.0 µg, and from 6.5 ± 0.8 µg to 11.6 ± 4.5 µg, respectively. The percentage of ingested arsenic excreted in urine remained constant at ∼ 58% for one volunteer before and after the rice diet, and was ∼ 69% for another. Mass balance established during a controlled dietary experiment over 10 days is shown to be a useful approach to evaluate in vivo bioaccessibility and metabolism of arsenic uptake from diet and is applicable to study with more subjects.     

Connecting changes to projects using a historical perspective: Towards some new canvases for researchers

Connecting changes to projects requires more than a statement. Conceptually, the management of changes as projects is a real challenge. A huge gap exists between conceptualizations in change management and in project management. The topic of communication represents a good example of this situation. Researchers who study organizational change all agree that communication is a key factor for success. But for some of them communication is a tool while for others communication creates changes. In project management, nearly the same situation occurs.     

Towards a multi-objective optimization approach for improving energy efficiency in buildings

The energy sector worldwide faces evidently significant challenges that everyday become even more acute. Innovative technologies and energy efficiency measures are nowadays well known and widely spread, and the main issue is to identify those that will be proven to be the more effective and reliable in the long term. With such a variety of proposed measures, the decision maker has to compensate environmental, energy, financial and social factors in order to reach the best possible solution that will ensure the maximization of the energy efficiency of a building satisfying at the same time the building's final user/occupant/owner needs. This paper investigates the feasibility of the application of multi-objective optimization techniques to the problem of the improvement of the energy efficiency in buildings, so that the maximum possible number of alternative solutions and energy efficiency measures may be considered. It further shows that no optimal solution exists for this problem due to the competitiveness of the involved decision criteria. A simple example is used to identify the potential strengths and weaknesses of the proposed approach, and highlight potential problems that may arise.     

Towards a consistent design approach for steel joints under generalized loading

The behaviour of steel joints is complex and requires the proper consideration of a multitude of phenomena, ranging from material non-linearity (plasticity, strain-hardening), non-linear contact and slip, geometrical non-linearity (local instability) to residual stress conditions, and complicated geometrical configurations. The component method is widely accepted as the practical approach in predicting the behaviour of steel joints and it provides detailed procedures to evaluate the strength and initial stiffness of steel joints, as specified in Eurocode 3.Current safety concerns for steel structures require that steel joints are designed to perform adequately under a wider range of loading conditions: besides standard static loading conditions, fire and seismic loading must often be considered. In addition, robustness requirements impose that joints present a minimum level of resistance for any arbitrary loading. Predicting the 3-D behaviour of steel joints under arbitrary loading must thus be achieved in a practical way.This paper presents the results of a series of experimental developments that attempt to contribute to the knowledge of the 3D behaviour of steel joints, under static and dynamic conditions, and to discuss a possible framework for these general conditions that is in line with the principles of the component method.     

Reducing CO2 emission from exhaust gases using molten carbonate fuel cells: a new approach

The aim of this study is to couple molten carbonate fuel cell (MCFC) stack with integrated gasification combined cycle fed by refinery residues, to remove CO₂ from gas turbine exhaust gases that have CO₂ emission rate of 14,200 ton/year. By applying multi-objective optimisation (MOO) using genetic algorithm, the optimal values of operating load and the corresponding values of objective functions are obtained. The MOO of the MCFC system regarding two scenarios is performed. The first scenario is minimisation of cost of electricity (COE) and CO₂ emission rate. Objective functions of the second scenario are the same as in the first scenario while CO₂ tax is taken into account. Results show that the second scenario has 29.5% lower average optimal COE and 2.5% lower average emission rate in comparison with the first scenario. A sensitivity analysis is also performed to study the effect of fuel price and CO₂ tax variations on optimal solutions.     

Long-term phosphorus budgets and an examination of a steady-state mass balance model for central Ontario lakes

The objective of this study was to evaluate, modify if necessary, and calibrate a mass balance steady-state total phosphorus (TP) model for use in the Precambrian Shield area of Ontario. Hydrologic data, TP mass balances and lake concentrations data were collected between June 1978 and May 1992 from seven oligotrophic and oligomesotrophic lakes located on the Precambrian Shield in central Ontario. Two of the lakes (Dickie and Harp) had substantial shoreline development; four lakes had alkalinities <25 μ eql⁻¹. The gross settling or loss coefficient, v, was underestimated when internal load was ignored. Long-term mean v ranged about three-fold, from 4.7 m yr⁻¹ in Plastic Lake to 13.7 m yr⁻¹ in Dickie Lake with an average for six lakes of 7.9 m yr⁻¹. The exception was Harp Lake where v was 23.2 m yr⁻¹. The difference in v between heavily developed Dickie and Harp Lakes may have been due to the unusually thick glacial tills in the Harp catchment and their likely ability to retain at least some of the TP from septic effluent. The current inability to predict septic TP retention rates by soils/tills, the highly variable nature of soils/tills, and the decades required to reach equilibrium after installation leave environmental managers with little choice but to apply the “precautionary principle” to ensure adequate protection of inland recreational waters and assume that soils do not retain septic TP. There was no evidence that enhanced sedimentation of TP (“oligotrophication”) occurred in any of the three most acidic lakes. In fact, losses via sedimentation were lowest in these lakes. Average retention, R ((input-output)/input) of TP during the ice-free months of May to November was much higher than average R in winter (December–April) in all lakes. Lack of wind-induced mixing, low biological activity and thermal stratification caused by ice cover make it more likely that stream loads are discharged directly from lakes during winter. Seasonal variation in retention suggests that R and v should be higher in warmer climatic zones. There may be no globally valid v, although the data presented here suggest that a regionally applicable estimate of v may be appropriate. The model should only be calibrated with a long-term data set and should be only used to predict long-term, average responses to changes in average TP loading.     

A different approach for predicting H(2)S((g)) emission rates in gravity sewers

All detrimental phenomena (mal odors, metal corrosion, concrete disintegration, health hazard) associated with hydrogen sulfide in gravity sewers depend on the rate of H(2)S emission from the aqueous phase to the gas phase of the pipe. In this paper a different approach for predicting H(2)S((g)) emission rates from gravity sewers is presented, using concepts adapted from mixing theory. The mean velocity gradient (G=gamma SV/micro; S is the slope, V the mean velocity), representing mixing conditions in gravity flow, was used to quantify the rate of H(2)S((g)) emission in part-full gravity sewers. Based on this approach an emission equation was developed. The equation was verified and calibrated by performing 20 experiments in a 27-m gravity-flow experimental-sewer (D=0.16 m) at various hydraulic conditions. Results indicate a clear dependency of the sulfide stripping-rate on G(1) (R(2)=0.94) with the following overall emission equation: where S(T) is the total sulfide concentration in the aqueous phase, mg/L; w the flow surface width, m; A(cs) the cross-sectional area, m(2); T the temperature, degrees C; K(H) the Henry's constant, molL(-1)atm(-1); and P(pH2S) the partial pressure of H(2)S((g)) in the sewer atmosphere, atm.     

Challenges for a shared European countryside of uncertain future. Towards a modern community-based landscape perspective

This paper addresses current changes in the highly diverse European landscape, and the way these transitions are being treated in policy and landscape management in the fragmented, heterogeneous and dynamic context of today’s Europe. It appears that intersecting driving forces are increasing the complexity of European landscapes and causing polarising developments in agricultural land use, biodiversity conservation and cultural landscape management. On the one hand, multifunctional rural landscapes, especially in peri-urban regions, provide services and functions that serve the citizens in their demand for identity, support their sense of belonging and offer opportunities for recreation and involvement in practical landscape management. On the other hand, industrial agricultural production on increasingly large farms produces food, feed, fibre and energy to serve expanding international markets with rural liveability and accessibility as a minor issue. The intermediate areas of traditionally dominant small and family farms in Europe seem to be gradually declining in profitability. The paper discusses the potential of a governance approach that can cope with the requirement of optimising land-sharing conditions and community-based landscape development, while adapting to global market conditions.     

2. The response of a laboratory stream system to PCB exposure: study of periphytic and sediment accumulation patterns

It has been proposed that the accumulation of PCBs by aquatic organisms is a physicochemical process that is governed by the equilibrium partitioning of PCBs between the organisms and the ambient water. This approach focuses primarily on the hydrophobicity of PCBs, while neglecting the biological impacts of PCB accumulation and possible differences in species-specific response. Furthermore, it does not reflect the complex mechanistic aspects of PCB accumulation. Current modeling, while focusing on accumulation via contaminated food, has been for large lake systems and is not appropriate for lower trophic organism interactions. The objective of this research was to evaluate the ecotoxicological fate of PCBs in a laboratory stream system and to determine if species-specific differences in the accumulation and toxic effects of PCBs existed. Bench scale experiments were conducted to determine kinetic and equilibrium parameters measuring algal uptake of PCB, and these results were used to explain the periphytic response to low level PCB exposure in the laboratory stream system. The results revealed that the accumulation rate, accumulation capacity and toxicity of PCBs differed for the species tested. The observation of PCB fate in the laboratory stream system indicated that PCB volatilization, sediment adsorption and periphyton bioaccumulation were the major pathways of PCB fate. The periphytic biolayer was the significant sink for PCB concentration. The accumulation capacity of periphytic biolayer to PCBs was one order of magnitude greater than that of sediments on a TOC basis. Comparison of the experimental data with model predictions illustrates that equilibrium partitioning models are not very accurate for predicting the accumulation of hydrophobic chemicals by low trophic biota.     

A new approach for estimation of the rock mass deformation modulus: a rock engineering systems-based model

Bulletin of Engineering Geology and the Environment - The deformation modulus of a rock mass is one of the crucial parameters used in the design of surface and underground rock engineering...     

An alternative approach for assessing eccentricities in asymmetric multistory buildings. 2. Inelastic systems

The approximate method, presented in the companion paper, for assessing modal eccentricities of elastic multistory buildings with simple eccentricity is extended in systems composed by elastoplastic resisting bents. Following the technique of the aforementioned paper for computing modal properties of such buildings by means of an equivalent single‐story system composed of elastic elements, modal capacity curves of these systems may also be drawn when the resisting elements are defined by a bilinear force–displacement (characteristic) curve. The procedure for constructing element‐characteristic curves is based on the methodology presented by the author in an earlier paper, and modal capacity curves of the equivalent single‐story system may be drawn by performing a non‐linear pushover analysis using the inertia force eccentricity of each mode of this system. Therefore, base shears and their eccentricities for the first two modes of vibration of multistory inelastic buildings can be determined as in real one‐story non‐linear systems. The method is illustrated in a 10‐story partial symmetric building, having along the direction of the ground motion three identical, inelastic, coupled wall bents. The structure is analyzed for a strong ground motion, equal to 1·5 × El Centro earthquake excitation, and the results are compared with those obtained from a step‐by‐step non‐linear time history analysis of the discrete member model. Copyright © 2007 John Wiley & Sons, Ltd.     

Filtration of suspensions through a multilayer medium in nonlinear kinetics of mass exchange. 2. Quantitative analysis

The paper sets out the results of the quantitative analysis of the filtration of suspensions through a double layer medium in nonlinear and linear kinetics of mass exchange, the constant filtration rate carried out based on strict theoretical relationships from the first part of the general paper. Using numerous examples with typical initial data, regularities of the variations of the output concentration of the suspension were set, just as the time of losses of the pressure head and characteristic times and especially the duration of a filtration cycle depending on the important model parameters.     

Towards to a system analytical and modelling approach for integration of ecological, hydrological, economical and social components of disturbed regions

As a consequence of surface coal mining, past landscapes within the Lusatian coal mining region were disturbed (land cover, forest, agro- and other ecosystems, geological material, hydrology), paralleled by strongly changed economic and socio-economic conditions (unemployment, emigration due to slowing down of mining activity in the region). The task is to restore the landscape and to improve the present state of the economic and socio-economic conditions, as well. Consented goal states for both the ecological and economic system in the region and consistent planning and management options (PMO) for such economic sectors, which are linked to natural resources (terrestrial, hydrological), are to be designed. They must be ecologically and economically evaluated, assessed and selected for real implementation.In order to handle such a complex problem, a comprehensive analysis of the whole system with subsequent multiscaled modelling efforts is needed. The final aim is to establish an interactive, effective, sufficiently simple decision support system for the actors in the disturbed region.The future responses of the landscape variables and the economical and social characteristics as an answer to economic sector PMO (e.g. PMO for control in agriculture, forestry, hydrology a.o.) can be approximately calculated, and subsequently evaluated and assessed by such an appropriately tailored simulation and decision support tool.In this study, the complex problem and the ecologic and economic system with its components are analysed and structured. Based on this, principles of stepwise model building and its usage (e.g. in if-than-simulation experiments as scenario analyses of the effects under changing non-modelled political and economical boundary conditions) toward an integrated approach are proposed.In this study, the present state of the disturbed region is described briefly (Section 1), and a rough scheme of the ecological and socio-economic structure of the region ( Section 2) as well as of the structure of the problem, which must be solved ( Section 3) and the role of the models in decision support ( Section 4) is outlined. In Section 5, the tasks of analysing and modelling of the components in the Lusatian coal mining region are derived, and in Section 6, the main steps in module building and its usage are briefly described. Finally, some conclusions are drawn.