Accumulation of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) via food to carps was investigated. PCDDs/PCDFs extracted from fly ash of a municipal waste incinerator were given to carps with food for 5 days. After 7 days from stop of dose, their concentrations in the edible parts of the carps were determined, and the following results were obtained.
(1) The 2, 3, 7, 8 substituted isomers accumulated more in carp than those not having TEF values.
(2) The PCDDs/PCDFs with greatar TEF values accumulated more in the carps than those with smaller TEF values, and a logarithmic relationship between the TEF values by WHO for mammalian or fish and relative accumulation ratio RAR was expressed approximately by the next equation.
RAR≈7 (TEF)^0.52
However, the TEF values of 1, 2, 3, 6, 7, 8- and 1, 2, 3, 7, 8, 9-hexa (Hx) CDD for fish were thought to be smaller than the expected values from the RAR.

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Influences of some providing substances on trichloroethylene (TCE) degradation of bioremediation through methane were studied. Three soil column tests were conducted to evaluate influences of methane concentrations, dissolved oxygen (DO) concentrations, inorganic nutrients concentrations, and hydrogen peroxide concentrations. In Test 1, influences of methane and DO concentrations were studied. A test column providing 5 mg · l^-1 of methane and 20 mg · l^-1 of DO showed highest TCE removal rate in this test. In Test 2, influences of inorganic nutrients were studied. It was excessive to provide 30 mgNO₃ · l^-1 and 20 mgPO₄ · l^-1 as inorganic nutrients for biostimulation. In Test 3, influences of hydrogen peroxide concentrations on TCE removal rate were investigated. There were no influences on TCE removal rate in test column provided hydrogen peroxide until 50 mg · l^-1. From these results, the suitable operating conditions were investigated for bioremediation of the TCE-contaminated groundwater through methane.

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For developing water treatment system to prevent waterborne Cryptosporidiosis, it is necessary to estimate the inactivation of Cryptosporidium. Recently, cell culture model has developed into a tool that can be used for assessing the viability and/or infectivity of Cryptosporidium oocysts. In this study, we investigated to develop quantative and sensitive detection method for determining the infectivity of Cryptosporidium oocysts by combining cell culture with enzyme-linked immunosorbent assay (ELISA). Human ileocecal epitherial cells (HCT-8), which were seeded in gelatin-coated 96-well plates at the density of 1 × 10⁴ cells · well^-1 and incubated at 37°C for 48h, were infected with the oocysts. After inoculation, HCT-8 cells were re-incubated with fresh culture media at 37°C for 48h, then were processed for ELISA. The absorbance values in ELISA were increased in an inoculating dose-dependent manner. In the experimental condition, the number of the oocysts from 1 × 10² to 3 × 10⁴ per well was quantitatively detected.

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This paper presents applicability of Fenton treatment to highly tetrachloroethylene (PCE)-contaminated groundwater. We performed flask-scale experiment in order to elucidate reaction mechanism in Fenton treatment of PCE in aqueous phase. Fenton treatment of PCE resulted in more than 95% of dechlorination and mineralization within 24 hours. It was found that the decomposition of PCE by Fenton treatment followed pseudo first order and its reaction coefficient was 0.17 h^-1. During 24 hours in the reaction experiment the concentration of chloride ion, total inorganic carbon, and PCE in the vials were determined. These results showed that more than 98% of PCE decomposed by Fenton treatment were compensated for the increase in chloride ion and CO₂ through the experiment and mineralization rates derived from the increase of CO₂ are almost same to dechlorination rates from the increase of chloride ion. Detected trichloroacetic acid from GC-MS and GC-ECD analysis explained only 1% of decomposed PCE in the reaction experiment. This study suggested that both processes of dechlorination and mineralization proceeded almost simultaneously in the PCE decomposition by Fenton treatment, not via intermediates such as acetic acid and dichloroacetic acid.

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In order to remove pesticides from raw water, an injection guideline of powdered activated carbon (PAC) was investigated. We set up an objective value which should be under 0.4μg · l^-1 in the total concentration of pesticides in purified water. On the baises of the analytical data of 70 pesticides found in raw water and purified water with PAC treatment for two years (1996∼1997) in our water treatment plant, the adequate injection rates of PAC for various concentrations of total pesticides in raw water to satisfy the objective pesticide value were determined and then applied to purification of water in our plant in 1998. The injection of PAC based on the guideline resulted in approximately 87% removal of total pesticides from raw water, and consequently the concentration of pesticides in purified water almost cleared the objective value (0.4μg · l^-1) during the investigation except only a few days, in which the increase in the injection rate of PAC corresponding to the suddenly increased pesticides in raw water might be delayed.

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A quick and simple new technique for measuring the chlorophyll content of water was devised using a chlorophyll meter (MINOLTA SPAD-502) normally used for the chlorophyll content of plant leaves. A test sample was filtered and the SPAD value obtained from the filter was converted to chlorophyll concentration. This study presents a formula for converting SPAD values to chlorophyll concentration.
This technique is remarkably efficient for measuring the chlorophyll concentration of waters containing specific algae, such as red-tide or water bloom. It is not yet suitable for non-specific test water.

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