Stockhome: A Spreadsheet Model of Urban Heavy Metal Metabolism

Computer models for analysis,visualising and decision support in environmentalresearch have become increasingly popular. TheStockhome project, where the urban metabolism ofheavy metals in Stockholm was studied, resultedin a database with historical data of the use ofgoods containing cadmium (Cd), chromium (Cr),copper (Cu), lead (Pb), mercury (Hg), nickel (Ni)and zinc (Zn). A spreadsheet model was developedto study flows and stocks of the metalconsumption process and emissions. The modelindicates uncertainties of the data, societalaspects such as field of use and rights ofdisposition of the goods. By considering goods asthe drivers of the emissions, the model would bewell suited for policy support.     

Goods in the Anthroposphere as a Metal Emission Source A Case Study of Stockholm,Sweden

The aim of this study was to quantify the diffuse emissionsduring use of metal containing goods in the capital of Sweden,Stockholm. The following metals were studied: Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb), Mercury (Hg), Nickel (Ni) and Zinc (Zn).A major part of the metals are found in a protected environmentwhere degrading processes like corrosion are most limited. However, during the lifetime of some goods the metal release to the environment is significant. The quantitatively most dominant emissions were found for Cu and Zn. The tap water system and roofs/fronts (Cu) represent goods with large exposedareas but with relatively small release rates per unit. In contrast, brake linings, aerial lines and electrical grounding (Cu) and tyres, brake linings and chemicals (Zn) are allgoods with high release rates but mostly limited exposed stocks.High yearly emissions are also found for Pb, ammunition andsinkers dominate the calculated emissions totally. For Cr and Ni, stainless steel represent the major part of the stocks, butcorrosion was estimated to give only a minor contribution to the emissions. Potential emission sources, i.e. stabilisers,pigments and plated goods dominate the exposed Cd stock. Theseemissions were not quantified due to lack of data. Hg is currently phased out, but one major source of emission, i.e. the use of amalgam, will be continuously significant for several decades. The importance of the traffic sector is obvious. The emissionsfrom brake linings (Cu, Zn and Pb), tyres (Zn, Pb, Cr and Ni)and asphalt wear (Cu, Zn, Cr, Ni and Pb) are all of large importance for the total emission from respectively metal.     

Urban Metal Flows – A Case Study of Stockholm. Review and Conclusions

Metals have rapidly accumulated in the anthroposphere, especiallyin urban areas, indicating possible environmental and resource problems. Here, Stockholm City was chosen for a case study of urban metal flows, i.e. metal inflow to, metals in the stock of,and metal outflow from the anthroposphere to the biosphere. Themetal stock of Stockholm is large and still growing. The large amounts of metals in the solid waste fraction totally dominatethe outflow from the city. For major parts of the stock, the emissions from goods in use are negligible. There are, however,goods applications corresponding to significant emissions: e.g. the traffic sector (Cu, Zn, Cr, Ni, Pb), the tapwater system (Cu), roofs/fronts or other metal surfaces (Cu, Zn). Today's known metal flows from the anthroposphere of Stockholm to the biosphere and sewage sludge are quantitatively dominated by Zn(34 ton y^-1) and Cu (14 ton y^-1). Historical and present emissions have resulted in high metal concentrations insediments (especially Cd, Hg and Pb, but also Cu and Zn), groundwater (Cu, Hg) and in soils (Hg, Cu, Pb). At present theannual median concentrations are below the Swedish limits for metals in sewage sludge, even if the safety margins aresmall for Cd, Hg and to some extent Cu. The flows of Cu and Zn to Stockholm soils are high with a significant accumulationindicating an environmental impact in a longer time perspective.High levels of metals in surface sediments in the waterenvironments reflects an ongoing input where these metals aretransported from known (Cu, Zn) and or partly unknown (Cd, Hg, Pb) sources. In future urban areas, monitoring of metal flows must be performed both in the anthroposphere and the biospherein order to have a pro active approach to urban environmentalproblems and to get prompt answers to measures taken.     

Urban Metal Management The Example of Lead

The metal metabolism of an urban region, the City ofVienna, was investigated to discuss urban metal management strategies in view of environmental protection and resource conservation. About 90% of the metal stock is located in Vienna's buildings and infrastructure, whilst only 10% is in the landfills. The city stock represents a potential source for diffusive emissions. However, the control of the current environmental policy concentrates mainly on landfill emissions. Diffusive emissions resulting from the losses over the use of metal containing goods in the city are widely dispersed and cannot be easily controlled due to numerous non-point sources. First investigations indicate that for certain applications, the diffusive stock emissions are as significant as other sources. At present, Vienna's known diffusive and point source lead emissions into air and water are about 40 to 50 times higher than comparable past loadings from geogenic Vienna. Furthermore, a life cycle approach from acid car batteries indicates that sustainable lead management should consider flows and stocks in the hinterland of the city too. The city metal stock also represents a potential resource. Leaded water pipes built-in in Vienna's city stock have the potential to produce 1.6 million traditional car batteries. In future such city mining strategies can partly replace ore mining.     

Urban Metabolism of Mercury Turnover,Emissions and Stock in Stockholm 1795–1995

This article accounts for the use of mercury (Hg) in differentactivities in Stockholm during the time period 1795–1995.Turnover of Hg is estimated to 122–440 tons, amounts recycled: 27–50 tons and total emissions of Hg are estimated to 90–390 tons. The stock was approximately 4.4–8.1 tons in 1995. 19th century handicraft occupations and medical treatment emitted alarge part of the Hg, emission sources that hitherto have beenunknown in Sweden. Emissions peaked around 1960, thereafter theemissions plummeted, being the result of decreased use of Hg fordental fillings and in products such as batteries, while recycling efforts had a limited effect on reducing total emissions. Based on this finding, the current focus on collectionof Hg containing products for long term storage in bedrock is questioned. If the aim is to reduce the potential for environmental hazards because of Hg it might be better to focusmore attention on the already emitted amounts since these are nearly 30 times greater than the amount of Hg in stock.     

Century Perspective of Heavy Metal Use in Urban Areas. A Case Study in Stockholm

The inflow and stock (amount in use) of heavy metals (cadmium(Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn)) in goods in 1995 have been quantifiedin the anthroposphere of Stockholm, Sweden. Statistics on national, regional and local level were used. Contacts were established with representatives from production and constructionin the industrial sector and with authorities. The results show that the stock of Cd is 0,2 kg per capita. For the other heavymetals the corresponding result per capita is: Cr 8, Cu 170, Hg 0,01, Ni 4, Pb 73 and Zn 40 kg. The inflow varies between2–8%of the stock indicating the importance of the stock. The lowestlevels are for Cu and Pb. Heavy metal levels in solid waste are high, between 15–45% of the amount in the inflow (Hg excluded), the lowest values were for Cu and Pb. Thus, recyclingis incomplete. Long life expectancy goods form the majority of the stock but there is a tendency that short life expectancy goods increase their importance in the inflow. Concealedgoods are also more frequent in inflow than in the stock.     

Substance Flow Analysis and Source Mapping of Chemical UV-filters

Chemical ultraviolet (UV)-filters are used in sunscreens to protect the skin from harmful UV radiation which may otherwise cause sunburns and skin cancer. Commonly used chemical UV-filters are known to cause endocrine disrupting effects in both aquatic and terrestrial animals as well as in human skin cells. Here, source mapping and substance flow analysis were applied to find the sources of six UV-filters (oxybenzone, avobenzone, 4-methylbenzylidene camphor, octyl methoxycinnamate, octyl dimethyl PABA and homosalate) and to identify the most dominant flows of these substances in Denmark. Urban water, composed of wastewater and surface waters, was found to be the primary recipient of UV-filters, whereby wastewater received an estimated 8.5–65 tonnes and surface waters received 7.1–51 tonnes in 2005. In wastewater treatment plants, their sorption onto sludge is perceived to be an important process and presence in effluents can be expected due to a lack of biodegradability. In addition, the use of UV-filters is expected to continue to increase significantly. Not all filters (e.g., octyl dimethyl PABA and homosalate) are used in Denmark. For example, 4-MBC is mainly associated with self-tanning liquids and private import of sunscreens.     

Behavior of endocrine-disrupting chemicals in leachate from MSW landfill sites in Japan

Endocrine-disrupting chemicals (EDCs) in landfill leachates and the effluent from leachate treatment facilities have been analyzed by many researchers. However, seasonal and yearly variations and the influence of landfill age are still not clear. In this study, leachate was sampled on four occasions each, at different seasons, from two MSW landfills which receive different waste material. Then, the quantities of alkylphenols (APs), bisphenol A (BPA), phthalic acid esters (PAEs) and organotin compounds (OTs) in leachate were determined. By sampling leachate from landfill cells of different age, the long-term behavior of EDCs was studied. Furthermore, leachate was also sampled at different points in the process of a leachate treatment system, and then the behavior of EDCs in the facility was studied. The concentrations of APs were as low as in surface waters, and OTs were not detected (detection limit was 0.01 microg/l), while BPA and DEHP, which were the most abundant of the four substances measured as PAEs, were found in all the leachates that were measured. Concentrations of BPA and DEHP were almost constant regardless of season, except for a couple of low concentrations observed for BPA. The varying composition of landfilled waste did not influence BPA and DEHP in leachate. Concentration of BPA in raw leachate tends to decrease as the years go by, but the concentration of DEHP was observed to remain at a constant level. BPA was considerably degraded by aeration for leachates from the two landfills, except when the leachate temperature was low. Aeration, coagulation/sedimentation, and biological treatment could not remove DEHP.     

Greenhouse gas emission reduction and environmental quality improvement from implementation of aerobic waste treatment systems in swine farms

Trading of greenhouse gas (GHG) emission reductions is an attractive approach to help producers implement cleaner treatment technologies to replace current anaerobic lagoons. Our objectives were to estimate greenhouse gas (GHG) emission reductions from implementation of aerobic technology in USA swine farms. Emission reductions were calculated using the approved United Nations framework convention on climate change (UNFCCC) methodology in conjunction with monitoring information collected during full-scale demonstration of the new treatment system in a 4360-head swine operation in North Carolina (USA). Emission sources for the project and baseline manure management system were methane (CH4) emissions from the decomposition of manure under anaerobic conditions and nitrous oxide (N2O) emissions during storage and handling of manure in the manure management system. Emission reductions resulted from the difference between total project and baseline emissions. The project activity included an on-farm wastewater treatment system consisting of liquid-solid separation, treatment of the separated liquid using aerobic biological N removal, chemical disinfection and soluble P removal using lime. The project activity was completed with a centralized facility that used aerobic composting to process the separated solids. Replacement of the lagoon technology with the cleaner aerobic technology reduced GHG emissions 96.9%, from 4972 tonnes of carbon dioxide equivalents (CO2-eq) to 153 tonnes CO2-eq/year. Total net emission reductions by the project activity in the 4360-head finishing operation were 4776.6 tonnes CO2-eq per year or 1.10 tonnes CO2-eq/head per year. The dollar value from implementation of this project in this swine farm was US$19,106/year using current Chicago Climate Exchange trading values of US$4/t CO2. This translates into a direct economic benefit to the producer of US$1.75 per finished pig. Thus, GHG emission reductions and credits can help compensate for the higher installation cost of cleaner aerobic technologies and facilitate producer adoption of environmentally superior technologies to replace current anaerobic lagoons in the USA.     

The Origin And Fate Of Volatile Trace Components In Municipal Solid Waste Landfills

The content of readily volatile halogenated hydrocarbons (chlorinated and chlorinated, fluorinated hydrocarbons (VCCs/CFCs)) and the BTEX aromatic substances (benzene, toluene, ethylbenzene and xylene) in municipal solid waste (MSW) was determined by two different methods. Moreover, the emission potential of these substances via the gas and leachate phase was investigated during the different biological degradation phases in the landfill. Trichlorofluoromethane (R11), dichlorodifluoromethane (R12) and dichloromethane (R30) were the dominating halogenated trace substances detected in the MSW. In the acid phase, with some VCCs/CFCs the emittance may take place up to 30% via the water phase. Hexane, benzene, and toluene could be detected in all tests. Toluene often occurred in relatively high concentrations in MSW. It could be shown that R11 degraded into dichlorofluoromethane (R21).     

Exploration of urban deposits: long-term prospects for resource and waste management.

Many materials currently in use are potentially available to become raw materials for future production if the materials are recycled instead of discarded as solid waste. However, the structure and life-expectancy of these secondary resources have not been sufficiently examined, and comprehensive methods for forecasting the availability of such materials are still lacking. This study presents a method for identifying anthropogenic material stocks in combination with the method of material flow analysis (MFA). The method was applied to copper in Switzerland as an example, with the focus on use in buildings. The exploration concept was a three-step process. First, a MFA identified the relevant stocks within the inventory of the region. Second, these stocks were inventoried through a building stock model and determination of key parameters that were defined by surveying selected buildings and from the literature. Third, the study team developed a dynamic MFA model to describe the copper stocks and flows during the period 1900-2000. The results of the copper stock calculation (in kg capita(-1)) were: buildings 79 +/- 11, infrastructure 107 +/- 25, movables 34 +/- 9, landfills 50 +/- 12. The calibrated model enabled the study team to develop resource and waste management scenarios forecasting waste flows. It is shown that the conversion of buildings into other uses may affect the waste flows significantly.     

Pilot-scale studies on the effect of bromine addition on the emissions of chlorinated organic combustion by-products

The addition of brominated organic compounds to the feed of a pilot-scale incinerator burning chlorinated waste has been found previously, under some circumstances, to enhance emissions of volatile and semivolatile organic chlorinated products of incomplete combustion (PICs) including polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs). This phenomenon appears to be sensitive to temperature and combustion conditions. This paper reports on a study to evaluate the emissions of organic combustion by-products while varying amounts of bromine (Br) and chlorine (Cl) are being fed into a pilot-scale incinerator burning surrogate waste materials. The surrogate waste was fed at a constant molar halogen input rate, with varying Br/Cl molar ratios. In these tests, an approximately 30% decrease in the total PCDD/F concentrations due to the addition of Br was observed. This decrease appears to be a decrease only in the chlorinated dioxin and furan species; other halogenated dioxins and furans were formed instead. PCDD/F homologue distribution shifted towards the higher chlorinated species. Perhalogenated or nearly perhalogenated mixed bromo-chloro furans were also observed in quantities that could potentially account for the observed decrease in PCDDs/Fs. This research illustrates the need for careful trial burn planning if Br will be present in the facility's feed-stock during normal operation.     

Recovery of polypropylene and polyethylene from packaging plastic wastes without contamination of chlorinated plastic films by the combination process of wet gravity separation and ozonation

Wet gravity separation technique has been regularly practiced to separate the polypropylene (PP) and polyethylene (PE) (light plastic films) from chlorinated plastic films (CP films) (heavy plastic films). The CP films including poly vinyl chloride (PVC) and poly vinylidene chloride (PVDC) would float in water even though its density is more than 1.0 g/cm³. This is because films are twisted in which air is sometimes entrapped inside the twisted CP films in real existing recycling plant. The present research improves the current process in separating the PP and PE from plastic packaging waste (PPW), by reducing entrapped air and by increasing the hydrophilicity of the CP films surface with ozonation. The present research also measures the hydrophilicity of the CP films.In ozonation process mixing of artificial films up to 10 min reduces the contact angle from 78° to 62°, and also increases the hydrophilicity of CP films. The previous studies also performed show that the artificial PVDC films easily settle down by the same. The effect of ozonation after the wet gravity separation on light PPW films obtained from an actual PPW recycling plant was also evaluated. Although actual light PPW films contained 1.3% of CP films however in present case all the CP films were removed from the PPW films as a settled fraction in the combination process of ozonation and wet gravity separation. The combination process of ozonation and wet gravity separation is the more beneficial process in recovering of high purity PP and PE films from the PPW films.     

Limitation of the concentration of organic pollutants in sewage sludge for agricultural purposes: A case study in South Spain

In 2000, the EU published the third draft of a future sludge directive entitled “Working document on sludge” where limit values for some organic compounds, including di-(2-ethyhexyl)phthalate (DEHP), sum of nonylphenol (NP), nonyphenol mono-(NP1EO) and diethoxylates (NP2EO), seven polychlorinated biphenyl congeners (PCB), polycyclic aromatic hydrocarbons (PAH) and linear alkylbenzene sulphonates (LAS), are fixed. In the present work, the monitoring of these organic compounds in sludge samples from four wastewater treatment plants (WWTPs) is reported. All WWTPs use anaerobic biological stabilization of sludge. The highest concentration levels were found for LAS, NPE and DEHP, in this order, with, in general, anaerobically-digested dehydrated sludge and compost samples being the most contaminated samples. DEHP, NPE, LAS and PAH were found at concentration levels above the limit values fixed in the third draft of the future EU sludge directive in the 44%, 88%, 13% and 6% of the analyzed anaerobically-digested dehydrated sludge and compost samples.     

中国2030年CO2排放总量预测研究

我国2005年和2010年CO2排放总量分别为55亿t和81.52亿t,“十五”和“十一五”期间年均增长率分别为11.0％和8.0％.中国2011-2015年、2016-2020年、2021-2025年和2026-2030年GDP年均增长率分别为8％、7％、6％、5％的经济发展模式与对应的能源消费弹性系数分别为0.5、0.5、0.4和0.3的能源发展模式,预测2030年燃煤、燃油和天然气CO2排放量及全国CO2排放总量.提出减少CO2排放总量对策,主要包括：调整能源结构,尽量减少煤炭消费量占能源消费总量的比例,增加石油、天然气和新能源的比例,提高CO2综合利用率,完善CO2管理政策与法律法规等.     

In-use polybrominated diphenyl ether (PBDE) stocks and atmospheric emissions in Japan

We estimated the in-use stocks of polybrominated diphenyl ethers (PBDEs) in Japan using a population balance model. The estimation is based on the domestic demand of PBDEs and the assumed survival rate of these products. Two cases relevant to the future regulation of commercial deca-BDE are considered, namely (1) deca-BDE declines at the same rate as the current rate of decline, and (2) deca-BDE is discontinued after 2020. The estimates of the decreasing rates of in-use penta-, octa-, and deca-BDE stocks were proportional with the measured decreases in the atmospheric concentrations of these substances. The in-use penta- and octa-BDE stocks could be depleted in the near future (500 and 60 tonne in 2013, and an estimated 20 and <1 tonne in 2020, respectively). Relevant to case 1, the in-use stocks of deca-BDE-containing products would be 28,000 tonne in 2013 and an estimated 1900 tonne in 2040, providing an ongoing source of deca-BDE emission to the environment. On the other hand, relevant to case 2, most of the deca-BDE would be phased out by 2040. The atmospheric emissions of deca-BDE were predicted at 84–841 kg/year in 2013 and an estimated 43–425 kg/year in 2020.     

Copper Emissions from Fuel Combustion Consumption and Industry in Two Urban Areas 1900–1980

The type of energy system andindustrial structure of urban areas is veryimportant for the total amounts of Cu emitted.The total per capita emission for the New Yorkarea is estimated to be approximately 4 timeslarger than Stockholm municipality between 1900–1980. The latter was mainly the result of largedifferences in energy systems and industrialstructure. Hydro-electric power and non fossilfuels were important energy sources for Stockholmwhile coal was a much more significant fuel forthe New York area. Metal processing hascharacterised the industries of Stockholm whilethe New York area was a national centre forcopper and petroleum refining as well as thechemical industry. In both cases the estimated Cuemissions from fuel combustion and industrydecreased from 1900–1980. But in the case ofconsumption related emissions the time trendsdiffer between the two urban areas. In Stockholmend use was the largest category of Cu emissionsduring the whole time period studied. In the NewYork area consumption related emissions becamethe largest source of Cu emission in the 1950s.     

Sources of Alkylphenols and Alkylphenol Ethoxylates in Wastewater—A Substance Flow Analysis in Stockholm, Sweden

This is a study of the sources of alkylphenol and alkylphenol ethoxylates in wastewater, including the new observation that the main contribution is from textiles. Alkylphenols and alkylphenol ethoxylates are widely used chemicals in various applications that are partly under environmental restrictions within Europe. The study sets out to analyze the most important sources of this large group of organic compounds in an urban wastewater system. A substance flow analysis (SFA) of the technosphere in Stockholm, Sweden in 2004 was conducted, allowing a comparison of 13 groups of goods’ emissions to wastewater. It was found that the groups of textiles and cleaning agents were the major sources to wastewater, while the group’s personal care products and paint and lacquers give smaller contributions. The content of alkylphenol ethoxylates in goods, especially in textiles, is a most significant source and is probably valid for other urban areas as well.     

Experimental study of behavior of endocrine-disrupting chemicals in leachate treatment process and evaluation of removal efficiency

An experimental study of the behavior of endocrine-disrupting chemicals (EDCs) in leachate treatment processes (aeration, coagulation and sedimentation, activated carbon adsorption, and advanced oxidation) was conducted and removal efficiencies were evaluated. Among target EDCs, concentrations of BPA (1800 times), DBP (10 times), BBP (40 times), and DEHP (30 times) in leachate are more than ten times higher than those in surface water. BPA, DBP, and BBP can be treated by aeration and DEHP, by advanced oxidation processes. BPA could not be effectively removed by coagulation and sedimentation because most of BPA partitioned in the supernatant. DEHP could hardly be treated by aeration. The removal ratios of DEHP were approximately 50–70% if the generated sediment was removed completely. The removal ratios of DEHP in leachate of 100 m³/d with 100 kg of activated carbon were 50–70%, assuming a complete mixing model. The concentration of DEHP was decreased to below one-tenth in 120 min by advanced oxidation processes.     

Aluminum in-use stocks in China: a bottom-up study

Characterization of the in-use stocks of a resource provides a perspective on the relationship between the amount of materials providing services and the state of development of a country or region. In this regard, we have performed what we believe to be the first aluminum in-use stock study for a developing country: China in 2000 and 2005. We found the in-use stocks to be 29 Tg Al (2000) and 49 Tg Al (2005), or 23 kg Al/capita (2000) and 37 kg Al/ capita (2005). These are lower limits because data were not available for all aluminum-containing products. The 2005 per-capita figure is roughly half that of the global average in-use aluminum stock, and about one-tenth that of highly developed countries such as Japan and the United States.