The sorption effects of the red tide and its contents on the ion exchange membranes have been investigated under various electrodialysis conditions. Aqueous NaCl solution suspended with the contents of the Chattonella antiqua, which is a typical phytoplankton species of the red tide, was passed through the desalting chamber in an electrodialysis apparatus. The effects of current densities and the contents of the Chattonella antiqua on electrodialysis were examined. pH change of the effluent and limiting current density in the desalting chamber were measured, and sorped species on the ion exchange membranes were analyzed. It was found that sorped species on the anion exchange membrane were mainly chlorophyll α-protein complexes and pheophytin α-protein complexes remarkably influenced the limiting current density; i. e., a pronounced decrease in the limiting current density occurred in the presence of the complexes. The contribution of Chattonella antiqua to the limiting current density of the cation exchange membrane was found to be very small during the electrodialysis. The sorption of Chattonella antiqua contents on the cation exchange membrane was almost undetectable.

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A feasibility study is carried out using cascaded electrodialysis with reflux (CER) to control ash components (Na⁺, K⁺, Ca²⁺, Mg²⁺) in cheese whey.
Perm-selective coefficients for K⁺, Ca²⁺, and Mg²⁺ with respect to Na⁺ (T_Na^K, T_Na^Ca and T_Na^Mg) are derived from their concentration changes during the deashing process. When the applied current is controlled proportionally to specific conductivity of deashing whey by the coefficient (1.3×10² A·S^-1·m^-1), T_Na^K, T_Na^Ca, and T_Na^Mg are 2.78, 2.27, and 1.69 respectively.
Deashing process of cheese whey is numerically analyzed assuming CER. Molar fraction of Na⁺ increases with the progress of deashing but the others (K⁺, Ca²⁺, Mg²⁺) decrease under the above condition. Comparing with the conventional electrodialysis, the changes of molar fractions of ash components are larger. They increase with the number of compartments, and when the number of compartments in each case is the same, the changes in the case of straight type are larger than in the case of cross type.
For the purpose to obtain raw materials in preparing infant formula similar to human milk using CER with 14 compartments, the most suitable perm-selective coefficients (T_Na^K, T_Na^Ca, and T_Na^Mg) for each ash component are calculated as 0.89, 0.79, and 0.59 respectively in the case of cross type, and as 0.91, 0.82, and 0.63 respectively in the case of straight type.

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Concerns raised over global warming caused by increases in CO₂, CH₄ and other greenhouse gases have become more urgent. The contribution of anthropogenic releases of CO₂ and CH₄ to the greenhouse effect is estimated at 49% and 17% respectively. However, compared with CO₂, the potential greenhouse warming effect is at as much as 32 times greater for CH₄, which is increasing at a rate estimated at 1.1% per year. Most of this may originate from biological resources. According to a report issued by the Intergovernmental Panel for Climate Change (IPCC) in June, 1990, 45% of the methane emissions may originate in paddy fields, lakes, wetlands and coastal zones.
In 1960, Takai showed that reductive production of CH₄ under waterlogged conditions occurred through a series of successive steps beginning with aerobic oxygen respiration, via nitrate respiration then progressing to manganese, iron and sulfate reducing reactions and finally to methane fermentation. This suggests that sulfate reducing reactions may be the predominate methane forming reaction in the coastal zone where the sulfate ions from sea or brackish waters are abundant.
Therefore, this study was designed to clarify the interaction between sulfate reducing bacteria and methane producing bacteria, and to identify the sources and mechanisms responsible for the emission of methane into the atmosphere.
Soil samples were waterlogged with: 1) sea water, 2) diluted sea water and 3) deionized water and incubated at 30°C. After 72 days their respective pH, Eh, sulfide and methane concentrations were determined.
In brief, the amount of sulfide produced at each waterlogged plot was in the following decreasing order: 100% sea water plot>50% sea water and 50% freshwater plot>25% sea water and 75% freshwater>100% fresh (deionized) water plot. The decreasing order coincided not only with the decreasing order for the amount of sulfate ion present in the waterlogging solution but also with the increasing order for the amount of methane produced after incubation for 72 days. The result shows that the predominance of sulfate reducing reaction may suppress methane forming reactions in brackish water zones. Chemical analyses also showed that the concentration of cations such as K⁺ and Ca²⁺ in the freshwater decreased when it was used to dilute the sea water; however, an equivalent effect for sulfate ion was not observed.

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The application of secondary ion mass spectrometry to the analysis of trace elements in kitchen salts using O^- as the primary ion to detect positive secondary ions has been studied. The following results were obtained.
1) Three-dimensional uniform standard samples were prepared by the fusing and freeze-dry methods.
2) The secondary ionic species derived from sodium chloride matrix and sea salt compounds and their relative ion intensities were defined.
3) The relative ion intensities of alkali metals, alkaline earth metals and aluminum were high.
4) The detection limits of the elements with high relative ion intensities were low. In particular, the detection limits of lithium was 4×10^-1 ppb.
5) The quantitative analysis of lithium, potassium, magnesium and calcium was carried out by the calibration curve method. Although the analytical values of SIMS differed little from those from usual methods, lithium could be analyzed at levels which could not be detected by the usual methods.

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The application of secondary ion mass spectrometry to the analysis of trace elements in kitchen salts using Cs⁺ as the primary ion to detect negative secondary ions has been studied. The following results were obtained.
1) The secondary ionic species derived from sodium chloride matrix and sea salt compounds and their relative ion intensities were defined.
2) The relative ion intensities of halogen elements, carbon, oxygen, phosphorus and sulfur were high.
3) The detection limits of the elements with high relative ion intensities were low.
4) The quantitative analysis of fluorine, bromine, iodine and phosphorus was carried out by the calibration curve method. Although the analytical values of SIMS differed little from those from usual methods, fluorine, iodine and phosphorus could be analyzed at levels which could not be detected by the ion chromatography.

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Titanium has not been used much in salt plants due to its high-cost and possibility of crevice corrosion. However, cost performance of titanium has been improving to be competitive to that of conventional materials such as copper alloys or stainless steel and furthermore low-priced titanium alloy (TICOREX) against crevice corrosion has been developed, which made the application of titanium to salt plants possible. In fact, a heat exchanger made of titanium started about two years ago.
In this report, advantages of application of titanium to salt plants were described, especially regarding corrosion resistance. And problems caused by using titanium were also reported based on the practical operation.

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