Applying probabilistic material flow analysis for quality control and management of waste recycling in steelmaking.

In modern steelmaking, multiple processes comprise a continuous manufacturing system, but not all phosphorus content data are connected or integrated into a holistic and systematic database. Disconnected data hinder the improvement of material management and resource efficiency in the industry. The objective of this study was to establish a method to evaluate material flows, reduce uncertainty, and perform quality control for waste recycling in the steelmaking industry. The results indicate that 10% of the phosphorus input is present in the final products, 30% accumulates in the slags, and more than 60% of the total mass remains in the processes. Comparing the material flow analysis results obtained using static and probabilistic approaches, the partition ratio of the phosphorus content in slags changes from 24.07% to 40.78%, but that in processes changes from 49.10% to 68.05%. This indicates that the variations in phosphorus content in slags and processes might affect the effectiveness of slag recycling and might increase the resource consumption required to maintain the quality of final products. The probability of forming substandard products in the baseline scenario is 0.43. Adopting a 50% removal rate, the probabilities of forming substandard products are reduced to 0.36 (waste removal scenario), 0.38 (slag reduction scenario), and 0.31 (raw material treatment scenario). The performance of raw material treatment and waste removal is more efficient for quality control. The method used in this study can be applied to evaluate the possible outcomes of waste recycling and reduce the probability of forming substandard products.

Health risk assessment of trace elements of ambient PM2.5 under monsoon patterns.

In order to identify the contribution to health risk derived from various emission sources, this study investigated monsoon variations in PM2.5 mass and concentrations of the associated trace elements in a region with complex pollution sources in central Taiwan. This study applied the Chemical Mass Balance model to analyze the source contribution of PM2.5. The source apportionment to obtain the risk contribution of different sources were conducted for different monsoon periods according to the monsoon patterns. In this way, the contributions of individual sources and chemicals to health risk under different monsoon types can be understood to support development of effective control strategies. Among the top contributors of PM2.5 during the north-east monsoon were Secondary Aerosol 28.93% >Coal Boiler 19.82% >Crustal Dust 15.99%; in south-west monsoon were Coal Boiler 37.29% >Traffic Emission 21.19% >Secondary Aerosol 17.84%. The total risk of cancer was above the acceptable risk (3.07 × 10-6), while the non-carcinogenic risk was within the acceptable range (0.262). The variation in the concentration and composition of PM2.5 was related to the change of monsoon type. During the north-east monsoon, the air mass had a long transmission distance and the PM2.5 concentration was relatively high. During the south-west monsoon, the air mass had a short transmission distance and the composition was mainly influenced by nearby emission sources, which resulted in higher risk due to chemical characteristics. To provide sound air quality management, attention should be paid to the composition of PM2.5 in addition to its concentration.

Twice the effort: Ineffectiveness of selecting air pollution control targets with emission quantity for risk reduction.

Protection of human health from air pollution has been typically pursued primarily via regulations of air quality standards and emission standards. Although reducing air pollution from the largest sources and placing more stringent emission limits on the industries of focus is a criterion used by decision makers to control air pollution, it is not clear whether this criterion is the most effective and efficient in improving health protection. Pollutants released from sources into the environment are spatially fluctuating rather than uniformly distributed, and hence, health risk is an issue of geographic variability. To address this issue, this study used a representative example of lead (Pb) in Taiwan. This study implemented an IO-RA methodology to redefine the effectiveness of air pollution management and rank the control priorities of target industries using different perspectives, i.e., environmental responsibility, economic benefit and repercussion potential. This study also considered the potential differences in policy effectiveness based on the air pollution control targets and ranked the industries according to their effectiveness in health risk improvement across the three perspectives and pure emission quantities. After determining the cause-effect chain of health risk through IO-RA, authorities can partner with specific industries according to the chosen effectiveness criteria and thus facilitate better policy performance.

Uncertainty analysis of remediation cost and damaged land value for brownfield investment.

Flexible land management that allows risk-based remediation approaches can increase local financial assistance in brownfield development investments. The evaluation of brownfields investment has always been mired in uncertainty because of the complexity of contamination and land policy. To clarify the uncertainty in investment costs resulting from a flexible risk-based land management, this research analyzes the uncertainty of remediation costs (Ir) and damaged land value (Ip). Sizable statistical data for 30,000 abandoned factories in Taiwan are used to derive the uncertainty of investment cost. The results show that the range and value of the uncertainty of Ip is more than Ir because the present land value and the change in flexible land management are the main sensitivity factors. The saved investment costs at the 90% confidence interval ranges five orders of magnitude. Moreover, investors could have saved approximately 5.74E+13 USD resulting from Ip and Ir. The study's two major findings with regard to investment risk in brownfield redevelopment are: (1) an explanation of the extent to which investment costs are to be reduced for investors by adjusting remediation goals depending on different land types; (2) characterization of the uncertainty of brownfields in the real investment market for brownfield redevelopment.

An agent-based model for an air emissions cap and trade program: A case study in Taiwan.

To determine the actual status of individuals in a system and the trading interaction between polluters, this study uses an agent-based model to set up a virtual world that represents the Kaohsiung and Pingtung regions in Taiwan, which are under the country's air emissions cap and trade program. The model can simulate each controlled industry's dynamic behavioral condition with the bottom-up method and can investigate the impact of the program and determine the industry's emissions reduction and trading condition. This model can be used elastically to predict the impact of the trading market through adjusting different settings of the program rules or combining the settings with other measures. The simulation results show that the emissions trading market has an oversupply, but we find that the market trading amounts are low. Additionally, we find that increasing the air pollution fee and offset rate restrains the agents' trading decision, according to the simulation results of each scenario. In particular, NOx and SOx trading amounts are easily impacted by the pollution fee, reduction rate, and offset rate. Also, the more transparent the market, the more it can help polluters trade. Therefore, if authorities want to intervene in the emissions trading market, they must be careful in adjusting the air pollution fee and program rules; otherwise, the trading market system cannot work effectively. We also suggest setting up a trading platform to help the dealers negotiate successfully.

Using risk elasticity to prioritize risk reduction strategies for geographical areas and industry sectors.

The total quantity of chemical emissions does not take into account their chemical toxicity, and fails to be an accurate indicator of the potential impact on human health. The sources of released contaminants, and therefore, the potential risk, also differ based on geography. Because of the complexity of the risk, there is no integrated method to evaluate the effectiveness of risk reduction. Therefore, this study developed a method to incorporate the spatial variability of emissions into human health risk assessment to evaluate how to effectively reduce risk using risk elasticity analysis. Risk elasticity analysis, the percentage change in risk in response to the percentage change in emissions, was adopted in this study to evaluate the effectiveness and efficiency of risk reduction. The results show that the main industry sectors are different in each area, and that high emission in an area does not correspond to high risk. Decreasing the high emissions of certain sectors in an area does not result in efficient risk reduction in this area. This method can provide more holistic information for risk management, prevent the development of increased risk, and prioritize the risk reduction strategies.

The influence of spatial resolution on human health risk co-benefit estimates for global climate policy assessments.

Assessment of the ability of climate policies to produce desired improvements in public health through co-benefits of air pollution reduction can consume resources in both time and research funds. These resources increase significantly as the spatial resolution of models increases. In addition, the level of spatial detail available in macroeconomic models at the heart of climate policy assessments is much lower than that available in traditional human health risk modeling. It is therefore important to determine whether increasing spatial resolution considerably affects risk-based decisions; which kinds of decisions might be affected; and under what conditions they will be affected. Human health risk co-benefits from carbon emissions reductions that bring about concurrent reductions in Particulate Matter (PM10) emissions is therefore examined here at four levels of spatial resolution (Uniform Nation, Uniform Region, Uniform County/city, Health Risk Assessment) in a case study of Taiwan as one of the geographic regions of a global macroeceonomic model, with results that are representative of small, industrialized nations within that global model. A metric of human health risk mortality (YOLL, years of life lost in life expectancy) is compared under assessments ranging from a "uniform simulation" in which there is no spatial resolution of changes in ambient air concentration under a policy to a "highly spatially resolved simulation" (called here Health Risk Assessment). PM10 is chosen in this study as the indicator of air pollution for which risks are assessed due to its significance as a co-benefit of carbon emissions reductions within climate mitigation policy. For the policy examined, the four estimates of mortality in the entirety of Taiwan are 747 YOLL, 834 YOLL, 984 YOLL and 916 YOLL, under Uniform Taiwan, Uniform Region, Uniform County and Health Risk Assessment respectively; or differences of 18%, 9%, 7% if the HRA methodology is taken as the baseline. While these differences are small compared to uncertainties in health risk assessment more generally, the ranks of different regions and of emissions categories as the focus of regulatory efforts estimated at these four levels of spatial resolution are quite different. The results suggest that issues of risk equity within a nation might be missed by the lower levels of spatial resolution, suggesting that low resolution models are suited to calculating national cost-benefit ratios but not as suited to assessing co-benefits of climate policies reflecting intersubject variability in risk, or in identifying sub-national regions and emissions sectors on which to focus attention (although even here, the errors introduced by low spatial resolution are generally less than 40%).

Assessing the transfer of risk due to transportation of agricultural products.

Health risk assessment (HRA) is the process used to estimate adverse health effects on humans. The importance and sensitivity of food chains to HRA have been observed, but the impact of the transportation of food has generally been ignored. This study developed an exposure assessment to demonstrate the significance of the transportation of agricultural products in HRA. The associated case study estimated the health risks derived from various sources of arsenic emissions in Taiwan. Two assessment scenarios, self-sufficiency and transportation of agricultural products, were compared to calculate risk transfer ratios that show the impact of agriculture transportation. The risk transfer ratios found by the study range from 0.22 to 42.10, indicating that the quantity of transportation of agricultural products is the critical factor. High air deposition and high agricultural production are the two main contributors to the effect of the transportation of agricultural products on HRA. Risk reduction measures could be applied to high-pollution areas as well as to areas with high agricultural productivity to reduce ingestion risks to residents. Certain areas that are sensitive to the transportation of agricultural products may incur more risks if emissions increase in agriculturally productive counties.

Extraction of heavy metals from contaminated soil by Cinnamomum camphora.

83 acres of rice paddy fields in Taoyuan county, Taiwan, were polluted by cadmium (Cd), chromium (Cr) and copper (Cu) through a nearby irrigation channel, and rice plantation was ceased in 1987. Camphor trees (Cinnamomum camphora) have been planted in 2 acre of the above fields since 1991. Heavy metal accumulation of roots, leaves, branches and heartwood of camphor trees were analyzed during 20-year afforestation. Averaged Cd contents of the roots were found larger than the ones of the branches, leaves, sapwood and heartwood of camphor trees growing in three polluted plots. Averaged diameters at breast height (DBH) of the planted camphor trees were 13-15 cm. Cd pollution did not significantly impact the growth of camphor trees, as similar DBH's were found from both polluted and control sites. Annual growths of DBH were from 0.63 to 0.77 cm year(-1). Planting camphor trees sequestered 68.8 ton biomass per acre. During 20-year period, 0.69-1.98 ton C year(-1) ha(-1) were sequestered on three polluted plots. The above numbers exceeded IPCC LULUCF reference values 0.31-0.53 ton C year(-1) ha(-1) for activities at forest lands.

Substance flow analysis and assessment of environmental exposure potential for triclosan in mainland China.

Triclosan (TCS) is a widely-used antimicrobial agent in many consumer products around the world, and China is a major producer and consumer of TCS. In this study substance flow analysis (SFA) was used to construct a static model of anthropogenic TCS metabolism in China in 2008. The systematic SFA results were used to determine possible exposure pathways and trends in environmental exposure potential through different pathways. TCS discharged in wastewater mainly flowed into surface water sediment, ocean, and soil, where it accumulates in aquatic and agricultural products that may pose a higher risk to human health than brief exposure during consumption. Only 22% of TCS discharged was removed in the built environment with the remainder discharged into the natural environment, indicating that anthropogenic TCS metabolism in China is unsustainable. Per capita TCS consumption increased 209% from 2003 to 2012, resulting in increased discharge and accumulation in the environment. If current trends continue, it will increase to 713 mg capita(-1) yr(-1) in 2015 and 957 mg capita(-1) yr(-1) in 2020. Accordingly, annual environmental exposure potential will increase from 388 mg capita(-1) in 2008 to 557 mg capita(-1) in 2015 and 747 mg capita(-1) in 2020, indicating an increasing trend of exposure to environmental TCS. Results of Pearson correlation analysis suggested that feasible countermeasures to reduce environmental exposure potential for triclosan would include encouraging the development of small cities, raising awareness of health risks, nurturing environmentally-friendly consumer values, and improving the environmental performance of TCS-containing products.

The Copper Balance of Cities: Exploratory Insights into a European and an Asian City.

Material management faces a dual challenge: on the one hand satisfying large and increasing demands for goods and on the other hand accommodating wastes and emissions in sinks. Hence, the characterization of material flows and stocks is relevant for both improving resource efficiency and environmental protection. This article focuses on the urban scale, a dimension rarely investigated in past metal flow studies. We compare the copper (Cu) metabolism of two cities in different economic states, namely, Vienna (Europe) and Taipei (Asia). Substance flow analysis is used to calculate urban Cu balances in a comprehensive and transparent form. The main difference between Cu in the two cities appears to be the stock: Vienna seems close to saturation with 180 kilograms per capita (kg/cap) and a growth rate of 2% per year. In contrast, the Taipei stock of 30 kg/cap grows rapidly by 26% per year. Even though most Cu is recycled in both cities, bottom ash from municipal solid waste incineration represents an unused Cu potential accounting for 1% to 5% of annual demand. Nonpoint emissions are predominant; up to 50% of the loadings into the sewer system are from nonpoint sources. The results of this research are instrumental for the design of the Cu metabolism in each city. The outcomes serve as a base for identification and recovery of recyclables as well as for directing nonrecyclables to appropriate sinks, avoiding sensitive environmental pathways. The methodology applied is well suited for city benchmarking if sufficient data are available.

Urban water metabolism efficiency assessment: integrated analysis of available and virtual water.

Resolving the complex environmental problems of water pollution and shortage which occur during urbanization requires the systematic assessment of urban water metabolism efficiency (WME). While previous research has tended to focus on either available or virtual water metabolism, here we argue that the systematic problems arising during urbanization require an integrated assessment of available and virtual WME, using an indicator system based on material flow analysis (MFA) results. Future research should focus on the following areas: 1) analysis of available and virtual water flow patterns and processes through urban districts in different urbanization phases in years with varying amounts of rainfall, and their environmental effects; 2) based on the optimization of social, economic and environmental benefits, establishment of an indicator system for urban WME assessment using MFA results; 3) integrated assessment of available and virtual WME in districts with different urbanization levels, to facilitate study of the interactions between the natural and social water cycles; 4) analysis of mechanisms driving differences in WME between districts with different urbanization levels, and the selection of dominant social and economic driving indicators, especially those impacting water resource consumption. Combinations of these driving indicators could then be used to design efficient water resource metabolism solutions, and integrated management policies for reduced water consumption.

Development and application of dynamic hybrid multi-region inventory analysis for macro-level environmental policy analysis: a case study on climate policy in Taiwan.

We develop a novel inventory method called Dynamic Hybrid Multi-Region Inventory analysis (DHMRI), which integrates the EEMRIOA and Integrated Hybrid LCA and applies time-dependent environmental intervention information for inventory analysis. Consequently, DHMRI is able to quantify the change in the environmental footprint caused by a specific policy while taking structural changes and technological dynamics into consideration. DHMRI is applied to assess the change in the total CO2 emissions associated with the total final demand caused by the climate policy in Taiwan to demonstrate the practicality of this novel method. The evaluation reveals that the implementation of mitigation measures included in the existing climate policy, such as an enhancement in energy efficiency, promotion of renewable energy, and limitation of the growth of energy-intensive industries, will lead to a 28% increase in the total CO2 emissions and that the main driver is the export-oriented electronics industry. Moreover, a major increase in the total emissions is predicted to occur in Southeast Asia and China. The observations from the case study reveal that DHMRI is capable of overcoming the limitations of existing assessment tools at macro-level evaluation of environmental policies.

Application of receptor-specific risk distribution in the arsenic contaminated land management.

Concerns over health risks and financial costs have caused difficulties in the management of arsenic contaminated land in Taiwan. Inflexible risk criteria and lack of economic support often result in failure of a brownfields regeneration project. To address the issue of flexible risk criteria, this study is aimed to develop maps with receptor-specific risk distribution to facilitate scenario analysis of contaminated land management. A contaminated site risk map model (ArcGIS for risk assessment and management, abbreviated as Arc-RAM) was constructed by combining the four major steps of risk assessment with Geographic Information Systems. Sampling of contaminated media, survey of exposure attributes, and modeling of multimedia transport were integrated to produce receptor group-specific maps that depicted the probabilistic spatial distribution of risks of various receptor groups. Flexible risk management schemes can then be developed and assessed. In this study, a risk management program that took into account the ratios of various land use types at specified risk levels was explored. A case study of arsenic contaminated land of 6.387 km(2) has found that for a risk value between 1.00E-05 and 1.00E-06, the proposed flexible risk management of agricultural land achieves improved utilization of land. Using this method, the investigated case can reduce costs related to compensation for farmland totaling approximately NTD 5.94 million annually.

Using risk maps to link land value damage and risk as basis of flexible risk management for brownfield redevelopment.

Brownfield redevelopment involves numerous uncertain financial risks associated with market demand and land value. To reduce the uncertainty of the specific impact of land value and social costs, this study develops small-scale risk maps to determine the relationship between population risk (PR) and damaged land value (DLV) to facilitate flexible land reutilisation plans. This study used the spatial variability of exposure parameters in each village to develop the contaminated site-specific risk maps. In view of the combination of risk and cost, risk level that most affected land use was mainly 1.00×10(-6) to 1.00×10(-5) in this study area. Village 2 showed the potential for cost-effective conversion with contaminated land development. If the risk of remediation target was set at 5.00×10(-6), the DLV could be reduced by NT$15,005 million for the land developer. The land developer will consider the net benefit by quantifying the trade-off between the changes of land value and the cost of human health. In this study, small-scale risk maps can illuminate the economic incentive potential for contaminated site redevelopment through the adjustment of land value damage and human health risk.

Integrating input output analysis with risk assessment to evaluate the population risk of arsenic.

Multimedia and site-specific risk assessments (RA) of major sources releasing arsenic (As) were converted into sector-based risk coefficients, which were integrated with the Input Output Table (IO) to analyze the association between sector activities and health risks. The developed IO-RA framework is a valuable tool for unfolding the risk chain linking the receptors, exposure pathways, emission sources, and production and consumption activities associated with various industrial sectors. The enlarged decision space along the chain can then be considered in planning risk management strategies. This case study estimates that air emissions of As result in 1.54 carcinogenic cases. Export is the primary driving force and accounts for approximately 48% of the final demand that leads to population risks of As. The ranking of the contribution of the five sectors in terms of total population risks is as follows: electricity supply (1.06E+00), steelmaking (2.2 × 10(-1)), cement kilns (1.50 × 10(-1)), semiconductor manufacturing (6.34 × 10(-2)) and incinerators (4.31 × 10(-2)). The electricity supply, steelmaking industry, and cement kilns are the major sectors, not only because their emissions directly cause risk but also because they have a stronger influence on the risk generated by other sectors.

Life cycle risk assessment of bottom ash reuse.

The life cycle thinking was integrated with risk assessment to develop the life cycle risk assessment (LCRA) methodology in this study. Because LCRA assessed risks from a life cycle perspective of the concerned policies, it was helpful to identify important sources, contaminants, receptors and exposure pathways along the life cycle of reuse activities. The case study showed that different reuse scenarios resulted in risk shift between different life stages and receptors, and using duration of pavement was an essential factor for risk management. When ash reuse strategies were made based on a focus on the stage of reuse, the rank of strategies were shown to be different from the one based on the total population risks over the entire life cycle. This demonstrated the importance of decision criteria used in selecting reuse strategies. The results also showed that when bottom ash was reused, the health risk was shifted to the laborers; the individual risks of laborers were higher than residents through exposure to Cr and Cd via inhalation and dermal contact. Although the population risk at the treatment stage was the highest, the smaller size of exposed population would make it quite effective to reduce the risk of the laborers.

Assessing the health risk of reuse of bottom ash in road paving.

Although the reuse of bottom ash has been favored gradually, reflected on regulations and researches, the associated risk is still an issue of great concern. This study quantified the health risks from multimedia transport and multi-pathway exposure to the concerned chemicals as a result of reusing bottom ash in road paving with consideration of various application scenarios. In particular, the using duration of the pavement was taken into consideration because movement of chemicals in the soils and groundwater would affect the subsequent exposure and risk. By using soil and groundwater transport modeling linked to food chain exposure assessment and incorporating the Monte Carlo method, the study identified Cr as the crucial toxicant and ingestion of drinking water and vegetables as the key exposure pathways. Furthermore, control of the using duration of road pavement is an essential factor of management and regulations to minimize the leaching of the hazardous constituents into the groundwater and subsequent contamination of food chain.

Comparative study of multimedia models applied to the risk assessment of soil and groundwater contamination sites in Taiwan.

The purpose of this study was to explore the applicability of two popular multimedia risk assessment models to three different soil and groundwater contamination sites in Taiwan. The Multimedia Environmental Pollutant Assessment System (MEPAS) and the Multimedia Contaminant Fate, Transport, and Exposure Model (MMSOILS) were selected because of their wide application and use. Three soil and groundwater contamination sites in Taiwan were employed as illustrative examples in the comparison of these two risk assessment models. Three exposure pathways were investigated, categorized as oral ingestion, dermal absorption, and inhalation. The results show that MEPAS and MMSOILS calculated similar cancer risks and hazard quotients in general, but were different by two orders of magnitude in cancer risk estimates for sites contaminated by volatile organic compounds (VOC). Using MMSOILS may not be appropriate for risk assessment of such sites, as it does not account for indoor inhalation as a potential exposure pathway in its risk calculations. Water ingestion, dermal absorption when showering and indoor inhalation were the three most predominant contributing exposure pathways for risk development among sites contaminated by VOCs. On the other hand, crop and meat ingestion were more important exposure pathways in the context of sites with non-VOC pollutants, because these hydrophobic contaminants may be bio-accumulative in plants and animals, and consequently enter the human body via food chains.

Applying multi-criteria decision-making to improve the waste reduction policy in Taiwan.

Over the past two decades, the waste reduction problem has been a major issue in environmental protection. Both recycling and waste reduction policies have become increasingly important. As the complexity of decision-making has increased, it has become evident that more factors must be considered in the development and implementation of policies aimed at resource recycling and waste reduction. There are many studies focused on waste management excluding waste reduction. This study paid more attention to waste reduction. Social, economic, and management aspects of waste treatment policies were considered in this study. Further, a life-cycle assessment model was applied as an evaluation system for the environmental aspect. Results of both quantitative and qualitative analyses on the social, economic, and management aspects were integrated via the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method into the comprehensive decision-making support system of multi-criteria decision-making (MCDM). A case study evaluating the waste reduction policy in Taoyuan County is presented to demonstrate the feasibility of this model. In the case study, reinforcement of MSW sorting was shown to be the best practice. The model in this study can be applied to other cities faced with the waste reduction problems.