The Offensine Odor Control Law of Japan, which regulate odor under the analytical measure-ments for individual concentration of eight odorants, have often no effect on control for actual multiple odor. Therefore, the evaluation and regulation for odor pollution based on measure-ment by sensory odor tests have become very important in recent years.
Tokyo Metoloporitan Institute for Environmental Protection developed “Triangular Odor Bag Method”, which has been widely applied by many local goverments and was presented as the standard method for sensory test of odor pollution by Japan EPA in 1981. However, this method is composed of two different procedures, one is for environment odor and the other is for exhaust odor, and some important problems on the basis of this test, such as reproduci-bility and variation of measured value and influence of characteristic of observers, are remaining in unsolved state.
In this paper, several consideration about the accuracy of obtained values by the procedure for environmental odor is carried out and following results are obtained.
As a relational expression between the dilution-hold of sample odor and the ratio of correct answer on tri-angle choice bag test have been presenter in current procedure under the basis of some assumption, it is not considered to be present to those relationship, because the distribution of olfactory sensitivity derived from this formula is considerably different from the distribution of it for human as previously reported. The 90 % confidence interval of variation for odor cone centration value is being within the range of one odor, owing to the occurrence of correct answer by chance in the response of observer. The variation of odor concentration value within the range of almost two oiler is caused by how to take the panel on the 90 % confidence interval. And also, it is recognized that the simular procedure have to take for both test of enviroment and exhaust odor.

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A simple method was studied for simultaneous determination of 8 heavy metals (Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb) in water. Ten ml of hydrochloric acid (1+11) and 30ml of 1 % sodium sulfite solutions were added to a 500ml of sample water, containing the heavy metals (5-50μg) . After stirring the sample water for 15 min to reduce Cr (VI) and Mn (VII), 20ml of titanium sulfate solutions (100 mg-Ti/l) as coprecipitant and 10 ml of 1% ammonium chloride solutions as buffer were added to the sample water, the pH of which was then adjusted to 10. After stirring again the sample water for 60 min, 3 ml of 2% sodium diethyldithiocarbamate solutions were added to it to complete precipitation of the heavy metals. The resulting precipitate was collected onto a membrane filter paper and air-dried for the fluorescent X-ray analysis. A gold target X-ray tube was used throughout the measurement. The goniometer was scanned from 30° to 72°. Each metal was determined by measuring the peak height of Kα line excepting that the Lα line was used for lead. Recoveries of the 8 metals examined were higher than about 90%. Only cobalt (II) ion was prevented by co-existances in sea water from coprecipi tating. The linear ranges of calibration curves were 0.01 to 1.0 mg/l for the above 8 metals.

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