[Investigations on the quality of well water in the Sakata-Akumi areas of Yamagata-ken].
Samples of well-waters were collected from 1988 through 1992 from 40 shallow wells (non-confined ground water), with samples taken from the well at 16 m depth from the ground surface up to the bottom of the well. Wells were located in the Sakata Akumi area of Yamagata-ken. The water quality was analyzed for 29 items and the results are as follows: 1) In the rural area on the coast of the Sea of Japan, the soil consists of sand, mud and gravel, and dry field farming with cultivation of fruit and vegetables is carried on. Concentrations of nitrate and nitrite nitrogen (NO2+3-N) in the well waters (n = 12) in this area were found to be in the range of 2.3-19 mg/l with the average of 8.2 mg/l, probably mainly derived from agriculture. On the other hand, in the rural area where the indigenous rock consists mainly of andesite and basalt and where rice crops are cultivated, the concentrations of NO2+3-N in the well water (n = 21) were found in the range of 0.15-2.9 mg/l with the average of 0.69 mg/l. 2) The concentrations of NO2+3-N were analyzed monthly for a total of 20 times between 1991 to 1992, from the Sea of Japan coastal region where the highest average of 19 mg/l from all samples was obtained. Analysis shows that a remarkable seasonal variation exists, with a range of 25-33 mg/l seen in both April and May during the two years observation, but only 14-17 mg/l in other months.(ABSTRACT TRUNCATED AT 250 WORDS)
Teraoka
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Institute for Engineering Studies, Kansei Kogyo Co., Ltd.
D007564:Japan; D008345:Manganese / Q000032:analysis; D008670:Metals / Q000032:analysis*; D009573:Nitrites / Q000032:analysis*; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
D008670:Metals; D009573:Nitrites; D014874:Water Pollutants, Chemical; D008345:Manganese