[in Japanese]

View full abstract

The Water Works Law requires water suppliers to monitor tap water quality periodically to make sure that the water meets the Drinking Water Quality Standards (DWQSs). In addition to DWQSs, Ministry of Health, Labour and Welfare provides Complementary Items, etc. for water suppliers to make sure the water quality in higher level by inspecting each item. The conformity to DWQSs, etc. is almost perfect, but there are still a few points where water quality does not meet DWQSs concerning to lead, bromate, etc. In order to reduce odorous substances to provide higher quality water, the DWQSs of geosmin and 2-methylisoborneol(2-MIB) were introduced in 2003 in Japan.
Water suppliers have been taking emergency measures against the outbreaks of musty odor in water sources. However, the tap water quality is still having odor and taste issue in some areas unfortunately. Though the number of affected people was over 20 million at worst in 1990, it is being about 3 million recently. Some water suppliers have installed advanced drinking water treatment process.

View full abstract

This paper describes the origins of drinking water odors in water resource and its control. Odor in drinking water can originate from biological sources or processes, from contamination by synthetic chemicals, and from corrosion or as a result of water treatment (e.g., chlorination). Odor compound may also develop during storage and distribution due to microbial activity. The majority of water supply systems in Japan have a river or surface water as their water source. These rivers are generally subject to concerns for many stakeholders, with different perspectives, who are located in a rather limited area. This fact makes it unfeasible for water monitor the water quality at the water source on its own. The monitoring systems instead, should be implemented in cooperation with various concerned parties or through the organized working of a council that includes various members of the entire watershed. Some of the existing systems can be effectively used in this manner.

View full abstract

To date, plastic materials have been used for packing foods as well as drugs. The crucial factor required for the use of plastics as food package is a safety. For packed foods, factors to keep a quality of food are also required for package properties. In particular, flavors responsible for food quality are closely associated with quality degradation due to the interaction of packed flavor with plastic materials. Thus, this review has been focused on the relationship between packaging materials and flavor degradation behavior.

View full abstract

Several cases which the odor for the plastics is something of problem are discussed. The considerable points of the odor evaluations are listed, and then the several kinds of quantifying methods of odor are described about those points. As the conclusion of the argument, which the Electronic nose should take part in the odor measurement field, is suggested. Finally, the practical data of odor measurement of electronic nose “FF-2A” was presented in four cases, odor intensity, discriminating or odor character, searching for the cause of odor and transmittance of odor.

View full abstract

Indoor air quality is affected by the emission of cooking odors, especially when living room and kitchen become as one space. The identification of odor components of roast meat with flavor was carried out by GC-Olfact and GC-MS methods. Several kinds of interior materials were evaluated for odor elimination purpose.
It was clarified that most of the odor components were composed of several kinds of aldehydes and sulfur compounds. To evaluate odor elimination ability of interior materials, odor air from roast meat with flavor was introduced into the 20L of stainless steel vessel in which interior material was put. In the result of analysis of outlet gas from that vessel, the concentration of those aldehydes and sulfur compounds was lessened in the case of calcium silicate plate as an interior material. And it was confirmed that odor strength can be considerably reduced using calcium silicate plate as odor elimination stuff.
In order to estimate practical usage of odor elimination ability, two connected 1m³ acryl plastic boxes were used as a kitchen-living model. Air containing odor components of roast meat with flavor was emitted in one of those boxes, and the emitted air was introduced into the other box in which some kinds of calcium silicate plate was put. The outlet gas was sampled and the durability of odor elimination was also evaluated. Some of calcium silicate plates show excellent odor elimination ability, and the attenuation time of the odor concentration was earlier than that of the control case. Moreover, sustaining ability of elimination of odor was confirmed for some kinds of calcium silicate plate.

View full abstract