A review on management practices, environmental impacts, and human exposure risks related to electrical and electronic waste in Vietnam: findings from case studies in informal e-waste recycling areas.

Electrical and electronic waste (e-waste) has become a global concern, especially in developing countries. In this review, we conducted a literature survey of e-waste management practices, processing activities, and adverse effects in Vietnam, an emerging country in Southeast Asia, by gathering data from peer-reviewed articles published between 2009 and 2021. This is the first review paper to comprehensively discuss management and research aspects regarding e-waste in an Asian developing country. Due to the lack of an effective management and recycling system, a certain portion of Vietnamese e-waste has been processed by informal sectors without appropriate recycling and pollution control technology, resulting in localized contamination and human exposure to toxic chemicals. Primitive processing activities, such as manual dismantling, open burning, and plastic recycling, have been identified as important contributors to the environmental emission and human exposure to toxic elements (notably As, Mn, Ni, Pb, Zn) and organic pollutants like flame retardants, PAHs, PCBs, and dioxin-related compounds. Informal e-waste processing from these small-scale workshops can release pollutants at similar levels compared to large-scale facilities in developed countries. This fact suggests an urgent need to develop management best practices for e-waste in Vietnam as well as other emerging and developing countries, in order to increase recycling efficiency and minimize their adverse impacts on environmental and human health.

Emission of Dioxin-like Compounds and Flame Retardants from Commercial Facilities Handling Deca-BDE and Their Downstream Sewage Treatment Plants.

Commercial mixtures of decabromodiphenyl ether (deca-BDE), a brominated flame retardant, contain not only polybrominated diphenyl ethers (PBDEs, mainly BDE-209) as the main component but also dioxin-like compounds (DLCs) such as polybrominated dibenzofurans (PBDFs). Deca-BDE handling facilities (DHFs) and sewage treatment plants receiving effluent from DHFs are point sources of DLC and flame retardant (FR) pollution. Here, we examined their emission in Japan. For DHF effluents, DLCs detected by the dioxin-responsive chemically activated luciferase expression (DR-CALUX) assay were 1.3-890 pg TCDD-EQ/L (median 46 pg TCDD-EQ/L), while PBDEs and other FRs were <2.0-110,000 ng/L (610 ng/L) and 150-4,800,000 ng/L (41,000 ng/L). Risk quotients based on predicted no-effect concentrations suggested that DLCs, decabromodiphenyl ethane (DBDPE), tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO), and bisphenol A bis(diphenyl phosphate) (BPA-BDPP) present significant risks for aquatic organisms. The concentrations of PBDFs, which are impurities in deca-BDE, were expected to decrease with the inclusion of deca-BDE in the Stockholm Convention list of persistent organic pollutants (May 2017). However, DLCs other than PBDFs and alternative FRs such as DBDPE, TDBP-TAZTO, and BPA-BDPP are likely still discharged. Additional findings indicate that strong (e.g., DLCs, DBDPE, and BPA-BDPP), but not weak (e.g., TDBP-TAZTO), hydrophobic compounds are sufficiently removed by current wastewater treatment processes in Japan.

Recycling Potentials of Precious Metals from End-of-Life Vehicle Parts by Selective Dismantling.

Recycling of some minor but essential scarce metals used in vehicles may serve as an important strategy to strengthen sustainable management of natural resources. Accordingly, this study focused on five precious metals (PMs): Au, Ag, Pt, Pd, and Rh, in both end-of-life conventional and next-generation vehicles. To explore their recycling potentials in Japan, we developed substance flow and scenario analyses based on estimations of PM contents per end-of-life vehicle (ELV) and ELV generations. The study predicts that in Japan, from 2015 to 2040, the content of PMs per ELV will range from 2 to 6 g, and the annual amount of PMs in ELVs will remain largely stable, at 14-15 t, but the proportions of PMs utilized in different vehicles, parts, and components will gradually change; in particular, increased proportions will occur in the printed wiring boards (PWBs) of next-generation vehicles. The results also show that, in Japan, totals of 33-53% of PMs in ELVs were recycled in 2015, and that by selective dismantling of PWBs and heating wires in the rear windows of ELVs, the recycling potentials of PMs could be optimally increased to a maximum of 62-83% by 2040.

Analysis of mismanaged plastic waste in Samoa to suggest proper waste management in Pacific island countries.

Pacific island countries are facing critical challenges in managing the growing amount of increasingly diverse wastes because of changing lifestyles and the concentration of populations in urban areas. Although marine plastic waste is an issue in the Pacific region, there have been almost no studies of the estimation and impacts of ocean plastic waste, and measures to control such waste, in these countries. Here, first we conducted a questionnaire survey about consumption and disposal of plastic products at households in Samoa as one of the examples of Pacific island countries to grasp the flow of plastic materials and awareness or behaviour for plastic waste. Then we quantified ocean plastic waste and discussed the effective and needed countermeasures in Pacific island countries. The total amount of mismanaged plastic waste was estimated to be 327,000 or 156,000 t y-1 (depending on the scenario) in Pacific island countries. The regional Pacific island countries contribution to the global total mismanaged plastic waste was estimated to range from 1.3% to 2.7%. The amount of mismanaged plastic waste per capita in some Pacific island countries, such as Solomon Islands and Micronesia, was also ranked highly globally. The main reasons seem to be that waste collection rates are relatively low in rural areas and rates of plastic waste generation are high. To implement solutions, including improving municipal solid waste collection, reducing plastic waste, improving the collection and recycling of plastics, and the integration of a number of policies is essential.

Correlation between Atmospheric Boundary Layer Height and Polybrominated Diphenyl Ether Concentrations in Air.

In this study, we aim to determine the correlation between the height of the atmospheric boundary layer (ABL) and the concentrations of polybrominated diphenyl ether (PBDE) congeners, in an effort to improve comprehension of the atmospheric behavior of PBDEs. We used the PBDE data in air (n = 298), which were measured by the Japan Ministry of Environment (JMOE) at 50 sites across Japan during the period 2009-2012. The height of the ABL, which directly affects the PBDE concentrations in the near-surface air, was estimated by employing data retrieved from the Japanese global reanalysis (JRA-55) database, using the parcel and Richardson number method. The ABL has shown a strong inverse relationship with BDE-47 and BDE-99 (p < 0.01). In contrast, there was less correlation between BDE-209 and the ABL (p = 0.258). These differing behaviors could be explained by differences in particle size distribution of PBDEs, where BDE-47 and BDE-99 are associated with gas phases and fine particles and BDE-209 is associated with coarse particles. To our knowledge, this paper represents the first large-scale analysis of correlations between the ABL and the concentrations of PBDEs in the air.

Greenhouse gas emissions from the treatment of household plastic containers and packaging: replacement with biomass-based materials.

The purpose of this study was to quantify the life-cycle greenhouse gas (GHG) emissions reduction that could be achieved by replacement of fossil-derived materials with biodegradable, biomass-based materials for household plastic containers and packaging, considering a variety of their treatment options. The biomass-based materials were 100% polylactide or a combination of polybutylene succinate adipate and polylactide. A scenario analysis was conducted considering alternative recycling methods. Five scenarios were considered: two for existing fossil-derived materials (the current approach in Japan) and the three for biomass-based materials. Production and waste disposal of 1 m(3) of plastic containers and packaging from households was defined as the functional unit. The results showed that replacement of fossil-derived materials with biomass-based materials could reduce life-cycle GHG emissions by 14-20%. Source separation and recycling should be promoted. When the separate collection ratio reached 100%, replacement with biomass-based materials could potentially reduce GHG emissions by 31.9%. Food containers are a priority for replacement, because they alone could reduce GHG emissions by 10%. A recycling system for biomass-based plastics must be carefully designed, considering aspects such as the transition period from fossil-derived plastics to biomass-based plastics.

Similarities in the endocrine-disrupting potencies of indoor dust and flame retardants by using human osteosarcoma (U2OS) cell-based reporter gene assays.

Indoor dust is a sink for many kinds of pollutants, including flame retardants (FRs), plasticizers, and their contaminants and degradation products. These pollutants can be migrated to indoor dust from household items such as televisions and computers. To reveal high-priority end points of and contaminant candidates in indoor dust, using CALUX reporter gene assays based on human osteosarcoma (U2OS) cell lines, we evaluated and characterized the endocrine-disrupting potencies of crude extracts of indoor dust collected from Japan (n = 8), the United States (n = 21), Vietnam (n = 10), the Philippines (n = 17), and Indonesia (n = 10) and for 23 selected FRs. The CALUX reporter gene assays used were specific for compounds interacting with the human androgen receptor (AR), estrogen receptor α (ERα), progesterone receptor (PR), glucocorticoid receptor (GR), and peroxisome proliferator-activated receptor γ2 (PPARγ2). Indoor dust extracts were agonistic to ERα, GR, and PPARγ2 and antagonistic against AR, PR, GR, and PPARγ2. In comparison, a majority of FRs was agonistic to ERα and PPARγ2 only, and some FRs demonstrated receptor-specific antagonism against all tested nuclear receptors. Hierarchical clustering clearly indicated that agonism of ERα and antagonism of AR and PR were common, frequently detected end points for indoor dust and tested FRs. Given our previous results regarding the concentrations of FRs in indoor dust and in light of our current results, candidate contributors to these effects include not only internationally controlled brominated FRs but also alternatives such as some phosphorus-containing FRs. In the context of indoor pollution, high-frequency effects of FRs such as agonism of ERα and antagonism of AR and PR are candidate high-priority end points for further investigation.

Factors affecting multiple persistent organic pollutant concentrations in the air above Japan: A panel data analysis.

Numerous reports have elucidated different statistical approaches to identify temporal trends in atmospheric persistent organic pollutant (POP) time series. However, the correlation of industrial activity with concentrations of atmospheric POPs in Japan has not yet been determined. Herein, a panel data analysis of a 16-year monitoring program (2003-2018) conducted by the Japanese Ministry of Environment was used to investigate a range of POPs in the atmosphere above Japan. This work focuses on polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCBz) collected each year at 53 sites across Japan. The panel analysis revealed that PCB, PCN, and PBDE concentrations were influenced by a combination of factors including year, industrial activity (municipal and industrial waste incinerators, cement kilns, steel industry, and secondary zinc production), population, temperature, and atmospheric boundary layer. However, HCB and PeCBz were not significantly affected by these factors. Industrial activity showed stronger positive correlations with all homologues of PCBs, PCNs, and PBDEs as compared to those demonstrated by population. Significant decreasing trends were identified for the atmospheric ∑PBDEs (half-life t1/2 = 9.4 years), ∑PCNs (t1/2 = 8.9 years), and ∑PCBs (t1/2 = 13.5 years) concentrations, while HCB and PeCBz showed slightly increasing or steady levels. As a statistical tool, panel data analysis can contribute to the assessment of spatial and temporal trends of POPs at a national scale, while elucidating different behavioral responses to numerous environmental variables.

Use of comprehensive target analysis for determination of contaminants of emerging concern in a sediment core collected from Beppu Bay, Japan.

In recent years, concern about the release of anthropogenic organic micropollutants referred to as contaminants of emerging concern (CECs) has been growing. The objective of this study was to find potential CECs by means of an analytical screening method referred to as comprehensive target analysis with an automated identification and quantification system (CTA-AIQS), which uses gas and liquid chromatography combined with mass spectrometry (GC-MS and LC-QTOF-MS). We used CTA-AIQS to analyze samples from a sediment core collected in Beppu Bay, Japan. With this method, we detected 80 compounds in the samples and CTA-AIQA could work to useful tool to find CECs in environmental media. Among the detected chemicals, three PAHs (anthracene, chrysene, and fluoranthene) and tris(isopropylphenyl)phosphate (TIPPP) isomers were found to increase in concentration with decreasing sediment depth. We quantified TIPPP isomers in the samples by means of targeted analysis using LC-MS/MS for confirmation. The concentration profiles, combined with previous reports indicating persistent, bioaccumulative, and toxic properties, suggest that these chemicals can be categorized as potential CECs in marine environments.

Dioxin-like activity in Japanese indoor dusts evaluated by means of in vitro bioassay and instrumental analysis: brominated dibenzofurans are an important contributor.

In our previous study, we demonstrated that dioxin-like activity in sulfuric-acid-treated extracts of Japanese indoor dust was higher than the activity in contaminated sediments. In the current study, we used high-performance liquid chromatography (HPLC) fractionation in combination with the dioxin-responsive chemical-activated luciferase gene expression (DR-CALUX) assay and gas chromatography-high-resolution mass spectrometry (GC-HRMS) to quantitatively evaluate dioxin-like compounds in indoor dusts. Selected four sulfuric-acid-treated extracts of indoor dusts were fractionated into seven fractions by means of HPLC with a nitrophenylpropylsilica column, and the activity in the first fraction of each extract was much higher than the activities in the other fractions. Therefore, each of the first fractions was further fractionated into 90 fractions by HPLC with an octadecylsilica column, and all the fractions were analyzed by means of the DR-CALUX assay. On the basis of elution characteristics, the active compounds in the fractions showing high activity were determined to be polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), coplanar polychlorinated biphenyls (Co-PCBs), and polychlorinated naphthalenes (PCNs), or supposed to be polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs). These compounds in the 33 dusts extracts were quantified by means of GC-HRMS, and their median-based contributions of the theoretical CALUX-TEQs [2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-tetraCDD) equivalent] chemically calculated for PBDFs, PCDDs, PCDFs, non-ortho Co-PCBs, PCNs, and mono-ortho Co-PCBs to the experimental values (38-1400 pg/g, median 160 pg/g) were 17%, 14%, 8.8%, 0.98%, 0.10%, and 0.019%, respectively. Our results indicate that PBDFs, which are not internationally regulated dioxins, were important contributors to dioxin-like activity in Japanese dust and that further analysis of PBDFs in indoor dust is required so that the risk of exposure to these compounds via dust can be assessed.

Screening of dioxin-like compounds in bio-composts and their materials: chemical analysis and fractionation-directed evaluation of AhR ligand activities using an in vitro bioassay.

Application of the dioxin responsive-chemical activated luciferase gene expression (DR-CALUX) bioassay to three compost products (kitchen garbage compost, treated sludge compost, and poultry manure compost) and their organic waste materials was performed for the screening of dioxin-like compounds. Phased sample preparation was conducted for the bioassay to yield separate crude, acid-stable, and carbon column fractions. Chemical analyses were also conducted for polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polyaromatic hydrocarbons (PAHs). Their determined WHO-PCDD/PCDF/dl-PCB-TEQ values were compared to the DR-CALUX results expressed as CALUX-TEQ to ascertain their contributions to overall activity. Overall all three compost products were polluted to a low level by persistent PCDD/PCDF/dl-PCBs in a few pg/g WHO-TEQ concentration range. The organic crude fraction showed non-persistent CALUX-TEQ values 2-4 orders of magnitude higher than those of WHO-TEQ. For the acid-resistant fractions of all samples, persistent CALUX-TEQ values were 1-8-fold higher than WHO-PCDD/PCDF/dl-PCB-TEQ values. Both TEQs correlated well for this fraction, which confirms the availability of CALUX for estimation of the actual WHO-TEQ level of the samples using reflux method with 44% sulfuric acid/silica gel, although the compost and material samples examined in this study contained much lower levels of WHO-TEQ: less than 1 pg/g in almost all cases. Additional carbon column treatment enhanced the potency and efficacy of CALUX activity in the three compost samples, which showed 1.6-4.4 times higher values of CALUX-TEQ than those obtained for the acid-resistant fraction. Although further DR-CALUX data collection for compost samples will be necessary, DR-CALUX is useful as a rapid screening method for monitoring dioxin-like compounds in compost.

Characteristics of gas from the fluidized bed gasification of refuse paper and plastic fuel (RPF) and wood biomass.

Energy recovery from small and medium scale waste thermal treatment facilities in the municipalities of Japan is challenging, owing to low power generation efficiency and high economic demands. Gas Engine (GE) generation is considered an efficient resource utilization method in these facilities. In this study, new and consistent feedstock, Refuse Paper and Plastic Fuel (RPF), and wood pellets were tested in an air-blown Fluidized Bed Gasifier (FBG) for syngas utilization in a GE. With temperatures ranging from 700 to 940 °C and varying Equivalence Ratios (ER) of 0.3-0.5, some of the most important product gas characteristics were analyzed, including the Lower Heating Value (LHV) and tar concentration levels. Gas composition results revealed that the concentration tendencies varied for the product gases CO, H2, and hydrocarbons, depending on the feedstock type, whereas the same tendencies were observed for CH4 and tar concentrations. Through the ER range, the LHV of product gas for RPF and wood pellets was 3.4-5.9 MJ/Nm3. Tar concentrations decreased to 2.5-14.0 g/Nm3-dry as the ER was raised. The optimal ER for LHV performance in GE generation was approximately 0.4 for RPF and wood pellets, and remaining tar concentrations were about 5.0 g/Nm3-dry at the gasifier exit.

Perinatal exposure to brominated flame retardants and polychlorinated biphenyls in Japan.

Brominated flame retardants (BFRs) are used to prevent combustion in consumer products. Examples of BFRs are polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), and tribromophenol (TBP). These compounds are reported to have adverse effects on human health and endocrine disrupting effects. The purpose of this study was to identify the Japanese perinatal exposure to PBDEs, hydroxylated PBDE metabolites (OH-PBDEs), TBBPA, and TBP compared with polychlorinated biphenyls (PCBs) and hydroxylated PCB metabolites (OH-PCBs). We investigated the concentrations of these compounds in maternal blood, maternal milk, cord blood, and umbilical cords from 16 Japanese mother-infant pairs by HRGC/HRMS. PBDEs were detected in all samples of maternal blood (mean+/-SD; median=25+/-23 pg/g; 18 pg/g wet weight), maternal milk (140+/-220 pg/g; 59 pg/g wet weight), cord blood (4.8+/-6.5 pg/g; 1.6 pg/g wet weight), and umbilical cords (3.1+/-3.1 pg/g; 2.1 pg/g wet weight). The mothers were divided into two groups, a high-concentration group and a low-concentration group. The percentage of BDE-47 showed the greatest difference between the two groups. 6-OH-BDE-47, TBBPA, and TBP were detected in all umbilical cord samples (mean+/-SD; median=8.4+/-8.1 pg/g; 8.0 pg/g, 16+/-5.5 pg/g; 15 pg/g, and 33+/-8.2 pg/g; 32 pg/g wet weight respectively), but not in all maternal blood or cord blood samples. These results indicate that OH-PBDEs, TBBPA, and TBP, in addition to PBDEs, PCBs, and OH-PCBs, pass through the blood-placenta barrier and are retained in the umbilical cord.

Life-cycle flow of mercury and recycling scenario of fluorescent lamps in Japan.

We summarized the mercury flow of mercury-containing products from their manufacture to their disposal in Japan and discussed the current management of mercury-containing hazardous household waste (HHW). The mercury flow originating from these products was estimated to be about 10-20 tonnes annually, about 5 tonnes of which was attributable to fluorescent lamps, the major mercury-containing product in Japan. The recent rapid increase in digital home electronics with liquid crystal displays (e.g.,televisions, personal computers, mobile phones, and digital cameras) has led to a marked increase in the production of backlights, which are also fluorescent and contain mercury. Most of the annual flow was disposed of as waste, with only 0.6 tonnes Hg recovered. The mercury flow for end-of-life fluorescent lamps (excluding backlights) was analyzed under three scenarios for Kyoto, Japan for 2003: the present condition scenario, the improved recycling scenario, and the complete recycling scenario. Under the present condition scenario, mercury flow was calculated to be 34 kg Hg for incineration, 21 kg Hg for landfill, and only 4 kg Hg for recycling. The complete recycling scenario shows a simple flow, with all mercury recycled. Under this scenario for Kyoto, we calculated that a cyclic system having 47 kg of mercury (3.5 tonnes Hg in Japan) could be established if all fluorescent lamps (excluding those stored in residences) were collected and recycled. Mercury is a HHW priority chemical, and we need to limit its use and establish a closed-loop system. There are currently no regulations to achieve this, and the management of most HHWs is left to local governments. Therefore, products are disposed of in landfills or incinerated, except for some that are voluntarily collected and recycled. In order to recycle all of the waste fluorescent lamps, we must have a complete recycling system that has a high rate of public participation in collection. We also must have a closed-loop system of mercury recovery and reuse in which all stakeholders participate. Furthermore, it is important to share information and policies regarding fluorescent lamp recycling and related technologies with other countries, especially those in other countries, where fluorescent lamps are becoming more popular because of their high energy efficiency and long life. Also, it is important to develop mercury free and energy efficient lamps including LEDs (light emitting diodes).

Transfer of brominated flame retardants from components into dust inside television cabinets.

Television (TV) set components are highly flame resistant, with their added brominated compounds such as polybrominated diphenyl ethers (PBDEs). These compounds might be released indoors via dust, which presents a potential exposure pathway for humans in the home environment. In this study, we collected dust from inside TV sets and TV set component samples (parts of housing front cabinets, rear cabinets and circuit boards) of five sets used in Japan. We measured BFRs (i.e., PBDEs, tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs)) and polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/DFs). Analytical results of the TV components showed that the concentrations of PBDEs, TBBPA and PBDFs (48,000 microg/g, 19,000 microg/g and 9600 ng/g as mean values, respectively) were all highest in the rear cabinets. The SigmaPBDD concentrations (460 ng/g as a mean value) detected were highest in the circuit board samples. The respective SigmaPBDE and SigmaPBDF concentrations in the dust samples were 67-500 microg/g (mean 300 microg/g) and 180-650 ng/g (mean 410 ng/g). Such concentrations were 2-3 orders of magnitude higher than those previously reported for house dust samples, which suggests that the brominated compounds are transferred from TV components into dust. Comparison of congener patterns of the brominated compounds in the dust identified the components as the source of these BFRs.

Potential source and emission analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in China.

The Chinese Government ratified the Stockholm Convention on Persistent Organic Pollutants (POPs) on 25 June 2004. As a party to the Convention, China is preparing its National Implementation Plan (NIP), which must be finished and submitted to the Conference of the Parties before November 11, 2006. The emission inventory and strategy for reducing unintentionally formed products is a very complex and difficult part of the NIP. In this paper, we analyzed the potential sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in China and calculated their possible emissions. We included municipal solid waste incineration, hazardous and medical waste incineration, pulp bleaching, sodium pentachlorophenate production and usage, illegal electrical and electronic waste ("e-waste") recycling, and ferrous and non-ferrous metal production, and prepared a preliminary analysis of dioxin emissions in China. The results show that ferrous metal production (104.2-6648.3g TEQ), non-ferrous metal production (2.6-3389.8 g TEQ), and sodium pentachlorophenate production and usage (120-368.0 g TEQ) should be major potential sources of dioxins and furans. Moreover, municipal solid waste and hazardous and medical waste incineration (35.5 g TEQ) should also be considered high priority sources owing to a rapidly increasing incineration ratio anticipated for the near future.

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in China and chemometric analysis of potential emission sources.

Aimed to give a preliminary image of dioxin pollution in China, chemometric analysis was performed to determine background dioxin levels during the period 1994-2002 and potential emission sources. Using principal components analysis (PCA), the congener profiles of 71 sediment samples from rivers, lakes, and sea bays around China were compared with the congener profiles of various known or suspected industrial, residential, and municipal dioxin sources to determine whether the dioxin residues typically found in a broad range of potential environmental sources could explain the presence of these chemicals in China. It was found that the background dioxin levels of China were similar to those of lightly polluted samples from other countries during the period 1994-2002. Primary ferrous ore sintering and secondary lead and aluminum smelters were the major sources of dioxin emission in China. Chloranil and wastewater from chemical plants, sodium pentachlorophenate, and pulp bleaching were also important sources of dioxin emission. Open burning of e-waste as well as diesel-fueled and leaded gas-fueled vehicles were additional possible sources of dioxin. In contrast to other countries, in China, flue gases from incineration of municipal waste, hazardous waste, and medical waste might be minor sources of dioxin emission.

Determination of physicochemical properties of tetrabromobisphenol A.

Aqueous solubility (Sw), 1-octanol/water partition coefficient (Kow), and vapor pressure of the nonionic form of 2,2',6,6'-tetrabromo-4,4'-isopropylidenediphenol (tetrabromobisphenol A or TBBP-A) were measured. From this, enthalpies of solution and vaporization were estimated. Furthermore, enthalpy of fusion and melting point were measured to estimate subcooled liquid vapor pressure, the infinite dilution activity coefficient, and Henry's law constant. Since TBBP-A is expected to exit in both ionic and nonionic forms at near neutral pH, pH effects on physicochemical properties were also examined. Because of the ionization of TBBP-A, Sw increased by five orders of magnitude, while Kow decreased by eight orders of magnitude. Furthermore, an analytical model based on mass balance and dissociation of TBBP-A was applied to represent the pH dependence.

Thermal destruction of wastes containing polychlorinated naphthalenes in an industrial waste incinerator.

A series of verification tests were carried out in order to confirm that polychlorinated naphthalenes (PCNs) contained in synthetic rubber products (Neoprene FB products) and aerosol adhesives, which were accidentally imported into Japan, could be thermally destroyed using an industrial waste incinerator. In the verification tests, Neoprene FB products containing PCNs at a concentration of 2800 mg/kg were added to industrial wastes at a ratio of 600 mg Neoprene FB product/kg-waste, and then incinerated at an average temperature of 985 °C. Total PCN concentrations were 14 ng/m3N in stack gas, 5.7 ng/g in bottom ash, 0.98 ng/g in boiler dust, and 1.2 ng/g in fly ash. Destruction efficiency (DE) and destruction removal efficiency (DRE) of congener No. 38/40, which is considered an input marker congener, were 99.9974 and 99.9995 %, respectively. The following dioxin concentrations were found: 0.11 ng-TEQ/m3N for the stack gas, 0.096 ng-TEQ/g for the bottom ash, 0.010 ng-TEQ/g for the boiler dust, and 0.072 ng-TEQ/g for the fly ash. Since the PCN levels in the PCN destruction test were even at slightly lower concentrations than in the baseline test without PCN addition, the detected PCNs are to a large degree unintentionally produced PCNs and does not mainly stem from input material. Also, the dioxin levels did not change. From these results, we confirmed that PCNs contained in Neoprene FB products and aerosol adhesives could be destroyed to a high degree by high-temperature incineration. Therefore, all recalled Neoprene FB products and aerosol adhesives containing PCNs were successfully treated under the same conditions as the verification tests.

Monitoring environmental burden reduction from household waste prevention.

In this study, the amount of prevented household waste in Kyoto city was quantified using three methods. Subsequently, the greenhouse gas (GHG) emission reduction by waste prevention was calculated in order to monitor the impact of waste prevention. The methods of quantification were "relative change from baseline year (a)," "absolute change from potential waste generation (b)," and "absolute amount of activities (c)." Method (a) was popular for measuring waste prevention, but method (b) was the original approach to determine the absolute amount of waste prevention by estimating the potential waste generation. Method (c) also provided the absolute value utilizing the information of activities. Methods (b) and (c) enable the evaluation of the waste prevention activities with a similar baseline for recycling. Methods (b) and (c) gave significantly higher GHG reductions than method (a) because of the difference in baseline between them. Therefore, setting a baseline is very important for evaluating waste prevention. In practice, when focusing on the monitoring of a specific policy or campaign, method (a) is an appropriate option. On the other hand, when comparing the total impact of waste prevention to that of recycling, methods (b) and (c) should be applied.