Tributyltin, triphenyltin and their degradation products were measured in 23 kinds, 47 species of fish and crustacean in 1993 at Tokyo Bay . Concentrations in crustacean were in the range of 16-56 ng TBTCI/g wet, 14-106 ng DBTCI/g wet, 6-53ng MBTCI/g wet, 5-50 ng TPTCI/g wet, 5-28 ng DPTCI/g wet, <1-4 ng MPTCI/gwet. Concentrations in fish muscle were 6-423 ng TBTCI/g wet, 5-35 ng DBTCI/g wet, <1-32 ng MBTCI/g wet, 20-146 ng TPTCI/g wet, <1-28 ng DPTCI/g wet, <1-26 ng MPTCI/g wet and those in fish liver were <3-245 ng TBTCI/g wet, 62-234 ng DBTCI/g wet, 14-94 ng MBTCI/g wet, <3-388 ng TPTCI/g wet, <3-172 ng DPTCI/ g wet, <3-19 ng MPTCI/g wet. TBT in fish liver was low compared with that in muscle, but TPT was detected in the same level. The present results show that relatively high concentration of organotin compounds in fish were still detected in Tokyo Bay and TBT was quickly metabolized in fish liver, while the degradation or derivatization of TPT was relatively slow. The data also suggests that TBT contamination of some fish in Tokyo Bay may further continue through food chain, because the concentration of organotin compounds in crustacean samples were relatively high.

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The structure of residents' subjective evaluation of the urban environment is studied by using fuzzy measures. The purpose is twofold : identification of local individualities and analysis of interactions between items of evaluation. The comprehensive evaluation is modeled by the Choquet integral, and fuzzy measures are identified by the convex quadratic programming. The data used in the analysis is obtained by the questionnaire survey carried out by the municipal government of Tokyo in 1991. Several problems such as treatment of subjective data given in the ordinal scale and interpretation of computed fuzzy measures are discussed. It is proved that the weight of each item is very small, but the weights of unions of two or three items are large enough to evaluate the environment, and the important combinations of items depend on local individualities.

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In order to estimate dry deposition and leaching rate dividedly onto the forest canopies, model calculation using material balance method (SO₄^2- was used as model substances) based on throughfall measurements was investigated at the four forests of Cryptomeria japonica, Quercus serrata, Q. myrsinaefolia and Chamaecyparis obtusa in Kobe city. Dry deposition rate on the four forest canopies was higher than that on open field, and the rate onto C. japonica forest was much higher than those of other forests. In this forest, total flux of acidic deposition was about three times larger than the incident deposition. K⁺, Mn, Mg²⁺ and Ca²⁺ were found to be leached from the four forest canopies, whereas H⁺, NH₄⁺, Zn, Cu and Pb were adsorbed in these canopies. And the orders ofthe leaching velocity were K⁺ > Mn, Mg²⁺> Ca²⁺, and Q. serrata > C. japonica > C.obtusa. These results were agreed to those of the leaching experiments using leaves ofabove trees. The fact that a significant correlation found between the leaching rates of Mn, Mg²⁺ and Ca²⁺ and the dry deposition rate of H+ indicate that the input of acidic deposition onto forest canopies had effects on nutrient cycling in the forest ecosystems. Above results show that our method based on both throughfall measurements and model calculation is available to the estimation of dry deposition and leaching rate onto the forest canopies.

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Atmospheric corrosion rates of steel in indoor and outdoor environments have been studied for two decades at the sites in Tokyo Metropolis and Yamanashi Prefecture. In general, corrosion rates in indoor environments are much lower than outdoor and in mountaineous area, the differences between corrosion rates in indoor and outdoor environments are much larger than that of urban and industrial areas. These differences are explained that the corrosions in outdoor environments are caused mainly by acid precipitation and indoor corrosions are caused mainly by air pollution. Long-term accumulated corrosion rates in indoor environments have nearly constant corrosion rates for the all exposure periods. This phenomenon indicates that the growth of corrosion layer in indoor environment does not introduce to the formation of effective layer of protection from further corrosion of the metal . On the contraly, the corrosion layer in outdoor environment produces effective protecting layer against it's further corrosion. This fact is very important that the accumulated corrosion rate observed in indoor environments is almost equal to that in outdoor environment such as urban, industrial areas and suburbs near megalopolis. Because it is necessary to protect almost all indoor metal materials from the rapid corrosion rate in indoor environments.

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