Environmental Strategy in the stagnant sea has focused on the regulation of total emission in COD, N and P, especially in the wastewater, for 25 years. In spite of significant reduction of COD, flowing to the sea area, the attainment rate for the Environmental Standard has not improved yet, to become almost constant rate. This fact is considered to be caused by non-point source of COD, N and P, such as the internal load from the sediments in the sea, the load from the not regulated industry, agriculture, and fishery field and also the rainfall-caused load from the combined sewer system and so on. We will have the 6^thregulation of total emission in COD, N and P. In this paper, present state of water pollution in the stagnant sea area and future problems are discussed, to present a future strategy in the 21^stcentury.

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Human pathogenic viruses such as Noroviruses and Rotaviruses contaminate water environments, including estuary and coastal areas. These pathogenic viruses in sea area would pose risks for infectious diseases among humans who eat contaminated sea products or play in contaminated bathing areas. It is of primary importance to comprehend the actual situation of the virus contamination of sea areas, which could be regarded as one of considerable reservoirs of human pathogenic viruses. In this article, recent knowledge in regards to the fate of human pathogenic viruses in sea areas is reviewed, and the moving pathway of these viruses estimated by scientific evidences is discussed.

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The growth of harmful microalga, Prymnesium parvum, causes red tides in embayments all over the world, and has caused severe damage to fisheries. The 4 chelators, such as bipyridine, ferrozine, bathophenanthroline disulphonate, or desfferrioxamine B, which bind iron, were evaluated for preventing P. parvum from growing under iron limitation. Only bipyridine and desfferrioxamine B inhibited the growth of microalga. Presumably, the two chelators will prevent P. parvum from uptaking iron and lead to iron deficiency. Furthermore, for the molecular mechanism of microalgal cells adapting to iron deficiency, the functional genes induced the transcription by means of iron deficiency were cloned using differential display analysis. The total 68 clones obtained were classified into 12 genetic types, of which 6 types were similar to the known functional genes and 6 types that indicated unknown sequences. The reverse northern analysis demonstrated that, among the 12 types, the transcriptions of 9 types were induced in the iron deficiency algal cells. The 3 types of the known functional genes, such as eucaryotic release factor, enolase, and heat shock protein, occupied 24 of the total 68 clones, suggesting that the algal cells under the stress of iron deficiency induce to transcript these functional genes to adapt to the environmental stress. In conclusion, the iron chelators reducing the algal growth may be a useful tool for regulating the harmful microalgal biomass, and the iron deficiency may provide the physiological stress for the microalgal cells.

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Cell density of the large diatom, Coscinodiscus wailesii causing Nori discoloration, chlorophyll a (Chl a) concentration and nutrient concentrations were determined in Harima-Nada, Seto Inland Sea, Japan from January to December 2004 and from October 2005 to January 2006. The sinking rates of 11 diatom species in natural seawater and six cultured diatom species isolated from same region were also determined. It was estimated that C. wailesii could account for 0-66% of Chl a standing stock in the water column. The sinking rate of C. wailesii cells in natural seawater ranged from 0.75 to 4.19m /day, which were higher than that of other diatom species. Additionally, cultured C. wailesii cells showed the highest sinking rate (2.12m/day) among the cultured diatoms. Due to its high sinking rate, it was suggested that C. wailesii could remove a great amount of nutrient from surface water and transport it to the bottom layer. We believe that C. wailesii plays a great role in the biophilic element cycling of coastal water during low temperature period.

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Growth and yield of Laminaria japonica culture in the coastal areas of Minamata City, Yatsushiro Sea, was experimentally studied for 3 years, from the 2004 to the 2006 seasons. The purpose of this study was to estimate the withdrawal of eutrophicating substances, such as N and P, and to increase juvenile fisheries resources through cultivation of such seaweed. Thin ropes on which the young sporophytes (seedling) were attached were cultured from early December, when water temperature dropped to 20°C, until middle of May, when water temperature increased to about 20°C. Final yield of seaweed for the 2006 season was 11.8 tons, 7.5 tons for Laminaria japonica, and 4.3 tons for Undaria pinnatifida, which has been cultured at the same time with Laminaria. These yields amounted to the withdrawal of 74.5 kg of N, and 10.3 kg of P, from the water. Further works and development for the future was described.

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Organotin compounds, tributyltin (TBT) and triphenyltin (TPT), tolerance of bacteria isolated from coastal seawater area and a few rivers and a swamp was examined. No relationship was found between bacterial organotin compounds tolerance and the organotin compounds contamination of ambient waters inhabiting these bacteria. Nine genera and 1 family bacteria such as Pseudomonas, Alteromonas and Enterobacteriaceae showed high organotin compounds tolerance ratios, whereas those of 2 genera bacteria such as Staphylococcus and Flavobacterium were low. Organotin compounds tolerance for a bacterium belonging to the same genus, however, was different for a variety reasons. Furthermore, organotin biosorption and biodegradation abilities of the above bacteria were investigated by using particle induced X-ray emission (PIXE) analysis and pyrocatechol violet (PV) assay method, respectively. Five strains of organotin compounds tolerant bacteria showed high TPT uptake and/or absorption ratios. The value for Enterobacteriaceae was markedly higher than those of the others. A high TPT degradation ability was found in one strain (Pseudomonas or Alteromonas) in these bacteria.

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As an urgent means suppression of red tides, we examined an application of ultraviolet rays for emergent treatment of Heterosigma akashiwo (Raphidophyceae). H. akashiwo was pre-cultured using f-2 medium for one month. Ultraviolet rays were applied directly to the sterilized petri dish, in which 2 ml H. akashiwo culture was added to 30 ml of f-2 medium. Ultraviolet rays were applied for about 30s (seconds), 60s, 120s, 300s and 900s. Ultraviolet ray strength were changed by 80μW, 400μW, 700μW and 1,500μW. In the counting of H. akashiwo, the living cell was distinguished by motility. Compared to the irradiation strength of ultraviolet rays, the cell growth was restrained in a condition of 80μW for 900 seconds, but the effect of ultraviolet rays on the cell growth was not recognized below the irradiation in cases of less than 900 seconds. Compared to the irradiation time of ultraviolet rays, the cell growth was restrainedin the case of 120 seconds with a condition of 700μW, but the restraining effect of the irradiation time was not recognized in the condition of less than 700μW. In irradiation time of 300 seconds or above in the case of more than 400μW, the cells do not multiply after irradiation. As a result, the relation between irradiation strength (X) and time (y) can be expressed as y=-202Ln (x) +1380 Irradiation strength of ultraviolet rays might influence the restraining effect rather than irradiation time, and its effect began to appear incases of more than 400μW.

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In order to cause contact between an oil slick and a photocatalytic material on seawater surface, titanium alkoxide was applied to hollow glass beads with a diameter of 30-70μm and a specific gravity of 0.15 to 0.60, and a film of titanium dioxide was formed on their surfaces. These beads were subjected to the experiments for degradation of oil slicks on seawater by means of the photocatalytic material. For the experiments, alkane, n-pentadecane (CH₃ (CH₂), ₁₃CH₃) with a thickness of approximately 0.2μm, n-pentadecane, was laid out on a distilled water surface at a volume of 20 mL and it was used as an experimental system. It has been observed that the beads were conveniently fixed on the boundary between the n-pentadecane and distilled water layers, when 10 mg of the beads were added to the system. Furthermore, it has been found that n-pentadecane was effectively degraded, after a small amount of sodium hypochlorite was dropped on the system, and ultraviolet light irradiated it using an exposure unit. As a result, the use of sodium hypochlorite promoted a degradable amount of oil slick 2.1 times greater than that without the reagent.

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In order to understand the actual effects of anthropogenic pollutants including endocrine disrupting chemicals (EDCs) on fish inhabiting the central coastal seawater area in Miyagi Prefecture, physiological indicators of marbled sole,Pleuronectes yokohamae and fat greenling,Hexagrammos otakii were investigated in December, 2005. Fish were obtained from the eastern coastal regions of Ishinomaki Bay (Ishinomaki Bay), the southern coastal regions of Matsushima Bay (Matsushima Bay: only marbled sole) and the eastern coastal regions of Ogatsu Bay (Ogatsu Bay).
In the case of marbled sole, no abnormality w as found in gonad morphology. In a few males from Ishinomaki and Matsushima Bays, low gonad-somatic indices (GSI) and high plasma estradiol (E₂)/testosterone (T) ratios were found. High hepatic microsomal cytochrome P-450 (Cyt. P-450) contents were also observed in a few fish from these sites. Significant negative relationship between hepatic Cyt. P-450 content and brain acetylcholinesterase (AChE) level, and between hepatic Cyt. P-450 content and plasma total thyroxine (tT4) level was found in both male and female marbled sole from Ishinomaki and Matsushima Bays. A negative relationship between GSI and hepatic Cyt. P-450 was found in male fish from both sites. In Marbled sole from Matsushima Bay, moreover, a negative relationship was observed between hepatic Cyt. P-450 content and the phagocytic activity of granulocytes.
In fat greenling, however, no significant abnormality was found in all physiological indices used for this experiment.
These findings suggest that (1) the health of marbled sole inhabiting the central coastal seawater area, particularly Ishinomaki and Matsushima Bays, in Miyagi Prefecture, is going to be influenced by exposure to environmental pollutants, including EDCs mainly derived from land area,(2) it is advisable to investigate the relationship between hepatic Cty. P-450 and brain AChE, or plasma tT4 or the phagocytic activity of granulocytes of flat fishes, for example marbled sole, as a mean of assessing environmental pollution of this kind.

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To determine the relationship between crystal growth rate and sodium chloride crystal quality, crystal growth experiments were performed using an agitated continuous crystallizer filled with model mother liquid as the solution, which was a concentrated ionexchange membrane brine. The following results were obtained.
(1) Under all experimental conditions, the crystal form was the same. The crysta form was influenced not by crystal growth rate, but by crystal particle size. Crystals of 0.3 mm or less were cubic, whereas crystals of 0.5 mm or more were spherical. For crystals of more than 0.3 mm and less than 0.5 mm, condensation and wear were observed.
(2) The weight of the solution inclusion decreased with an increase in crystal growth rate.
(3) The potassium and bromide content in crystals increased slightly with an increase in crystal growth rate. The rate of increase of the potassium or bromide ion content was low, under the conditions in which crystals easily condense. The potassium or bromide ion content decreased with an increase in crystal particle size for cubic crystals, however, it increased for spherical crystals.
(4) Assuming that the condensation of cubic crystals whose form is not degraded (i. e., adhesion of fine crystals) contributed to their growth and that condensation of crystals was difficult under the conditions of high wear, it was thought that the adhesion of fine crystals controlled the ion content in the crystals.

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The effects of the concentration and composition of salts on tofu gel hardness were studied. The effect of divalent cations such as magnesium and calcium on tofu gel hardness was remarkable. When the concentration of a salt that has a divalent cation was increased, tofu gel hardness generally increased. However, tofu gel hardness decreased when the magnesium chloride concentration was increased to more than 0.05 mol/l, compared with that in the case of calcium chloride. The effect of monovalent cations on tofu gel hardness was small. Even when the concentration of a salt that has a monovalent cation such as sodium chloride was increased, tofu gel hardness showed almost a constant value. For magnesium chloride-sodium chloride solution, it is suggested that sodium chloride does not significantly affect tofu gel hardness but contributes to the water retention of tofu.

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A salt production method using the evaporation procedure was investigated. The method for controlling the composition and the shape of salt was examined, which is useful in order to design the apparatus and establish the operating condition. The seawater from Noda (1 km from NODA, d epth 30 m) and the Sanriku deep seawater (31 km east from TODOGASAKId, epth 680 m) were used and the difference between two kinds of seawaters was reported.
A distinct difference was found in the shapes of the produced crystals obtained from individual seawater. However, the extracted salts showed no significant difference in the shape and the composition of crystals.
The change in the shape as well as the quantitative change in the composition of the produced crystals and the extracted salts by the amount of evaporation was revealed. The deposition process of calcium sulfate in the early stage of evaporation was also clarified.

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We studied the effect of an extracellular enzyme, E77 from a bacteria genus Streptomyces strain on jellyfish, Aurelia aurita. Aureria aurita dissolved completely within 1 hour at 50°C without stirring in presence of E77 containing solution. Without the enzyme, 83.5% of jellyfish remained in the fresh water and 75.3% in the seawater at 50°C even after 1 hour without stirring. Although the wastewater after E77 treatment revealed high value 1280mg/L of chemical oxygen demand (COD), by application of this new framed bioreactor packed with several microorganisms could reduce its value by 122mg/L.

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