The amount of cadmium (Cd) discarded by nonferrous mining and smelting, which have been pointed out as two of the main sources of Cd in the environment, was estimated using statistics on zinc production and the Cd-to-zinc (Cd/Zn) ratio in ore. The sums of Cd discarded by mining and smelting from 1915 to 1999 were estimated to be 3, 300 t and 28, 000 t, respectively. The amount of Cd discarded by mining was estimated to be larger before World War II (peaking in the 1930s) than after. On the other hand, the amount of Cd discarded by smelting was calculated to have peaked in the 1970s. We also discussed that to what extent the discarded Cd could be transported in the environment.

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Di(2-ethylhexyl) phthalate (DEHP) is mainly used as a plasticizer for flexible polyvinyl chloride (FPVC). The quantity of DEHP released into the environment from the DEHP production and the FPVC products manufacturing is estimated and reported in the Pollutant Release and Transfer Register (PRTR) system. The PRTR system, however, does not cover the releases of DEHP from FPVC products in use. In this paper, the quantity of DEHP emitted into the air from FPVC products in use was estimated. The quantity of DEHP contained FPVC was estimated using the amount of shipment and the lifetime function. Results of the estimation showed that "sheets for green houses" was estimated to be the main emission source and contributed half of the total emissions from FPVC products in use. Total DEHP emissions from FPVC products in use to the air were estimated to be 761 tons/year, which is comparable to approximately 50% of DEHP emissions in year 2001 reported in PRTR. It is concluded that FPVC products in use are a significant source of DEHP emissions to the environment, and the method presented here can be used to improve the emission estimations of chemicals similar to DEHP.

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In previous research, authors examined yearly trends of atmospheric sulfur dioxide (=SO₂) concentration in Chinese major cities during 1990's. It was suggested that the rate of SO₂ discharged from industry and removal of SO₂ by desulfurization systems, (=removal rate), determined the yearly trends of atmospheric SO₂ concentration every city. Although atmospheric SO₂concentration data and (SO₂) emission data are useful as an index of air pollution respectively, these two indices are not necessarily correlated. In this study, we changed SO₂ emission data in an industrial complex and data of SO₂ removal into atmospheric SO₂ concentration, respectively, using a simulation model which authors made based on the box model. They examined yearly trends at each city again from a viewpoint of SO₂ concentration. In the result, an average of 39.7% contribution of SO₂ discharged from industrial section in each mesh it was discharged. Several mesh including industrial cities, such as Lanzhou, Chongqing, were showed high contribution of SO₂. Moreover, the effect of removal of SO₂ by desulfurization systems in each mesh was an average of 11.0%. And it was suggested that the factor of yearly trends at each city was removal rate even when changed to concentration from SO₂ emission data.

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Since 1995, We carried out collection of disposal solid wastes by boring technique with improved core tube. The main results of observation and analyses for core samples were as follows.1) The methane which generated by fermentation and decomposition of organic waste was captured within soil layer covered waste. That methane obstructed growth of a plant on the soil layer.2) The fragments of wood, paper and textile in the core were not altered apparently. However, the pore within the layer consisted of such fragments were filled with methane.3) Some metals in the core sample have been glossy yet. Namely, it was clear that the internal condition of the landfill was anaerobic.4) Incinerator ashes contained Halite, Sylvite, Hydrocalumite and Lime mainly. Those components were disappeared by leaching and dissolution.5) Major ions in leachate consisted of Na⁺, K⁺, Mg²⁺, Ca⁺, NH₄⁺, C1^-, HCO₃^-, SO₄^2- and toxic heavy metals were not detected in leachate. Electric conductivity of leachate was related closely to chloride ion.6) Plasticizers in disposal plastics were stored in the landfill, and a portion of plasticizers was leached into the leachate.

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Among the industrial wastes, construction and demolition (C & D) wastes have been discharged in the range of about 70 million - 80 million tons/year in the past several years. Although the separation of C & D wastes has been progressed and their recycling rate has been increased since the Law for the Recycling of Construction Materials was enforced, reexamination of the meaning of these activities has not been performed yet from a viewpoint of chemical substances. In the present condition, it is difficult to control chemical substances at the construction and demolition sites. Under these conditions, the possibility of removal of hazardous chemical substances and organic contaminants at crushing and sorting facilities were investigated by using the sorted wastes from C & D wastes. The C & D wastes of 5.475 million tons/year were flowed into Saitama Prefecture in the fiscal year 2000. It was almost discharged from Saitama (56.6%) and Tokyo (36.5%). 99.3% of these wastes were processed at the intermediate treatment facilities. Especially, 67% of the amount was processed at the crushing and sorting facilities. Various kinds of chemical substances were analyzed about waste woods, waste gypsum boards, and mixed wastes which were taken from these crushing and sorting facilities. Separation of hazardous chemical substances was done successfully by dividing the waste woods into square lumbers and plates at the crushing and sorting facilities. It was also clarified that a lot of chemical substances gathered to the wood-chips for fuel or the dusts. In crushing and sorting of waste gypsum boards, the concentration of organic contaminants became high by mixing of papers. Since the degree of their contamination was high, it was required to reduce the organic substances by incineration, etc. And it was shown that disposal in a controlled landfill site was appropriate for the fine granules and dusts which were the residues of sorting. However, the dusts have a high possibility to become harmful industrial wastes as Pb. The development of some reduction methods of Pb is required.

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The origins and loads of chemicals discharged from waste landfills, such as bisphenol A (BPA), 4-nonylphenol (NP) and 1, 4-dioxane, which are of concern due to their influence on the ecosystem, are discussed based on the results of continuous monitoring of leachate and serial-batch leaching tests. The concentrations of BPA contained in leachate varied widely and was detected in many types of waste landfills. However, NP was detected at much lower concentrations than BPA. Although it was confirmed that NP was contained in plastics the same as BPA, especially plasticized polyvinyl chloride (PVC), the amount of NP leached from PVC was much less than that of BPA, because NP is a more hydrophobic substance than BPA. The results of continuous monitoring in leachate from old waste landfills showed that 1, 4-dioxane concentration decreased after 300mm of rainfall, despite increased BPA and NP concentrations. However, variations of loads on these three chemicals from those landfills showed a similar trend, and reached maximal levels after 1 week of rainfall, when the maximal volume of leachate in each landfill was recorded. Annual amounts of these chemicals in the leachate were estimated. The maximum was 2.6kg/year for BPA, 0.2kg/year for NP and 0.6kg/year for 1, 4-dioxane, respectively.

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The melting plant generates fly ash that is rich in volatile heavy metals such as Pb, Cu and Zn. The fly ash is chemically treated by chelating agents and is then solidified in Portland cement. However, research reported on the leaching of treated ash with both chelating agents and Portland cement is limited. In this study, a sequential extraction procedure and column test were carried out in order to elucidate the characteristics of the leaching behaviour of the treated ashes obtained from the melting plant. In the sequential extraction procedure, Cu was principally distributed in the organic matter fraction in the treated ash. This observation suggests that Cu binds to the chelating agent. In the column test, the typical leaching patterns of most heavy metals involved early leaching followed by a decrease in the leaching rate. Furthermore, the column tests for three types of solvent (distilled water, pH4, pH2) were carried out. The solvent pH did not affect the leachate pH under this experimental condition. However, the leaching rates of Pb and Cu increased with the decrease in solvent pH.

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