| Groundwater Quality Monitoring System |
The Water Pollution Control Law Article 15 orders that prefectural governments and ordinance-designated cities should regularly observe the pollution status of the groundwater quality. These governments measure the groundwater quality according to the measurement plan prepared by prefectural governments every year.
The nationwide general surveys (those surveys implemented to comprehend the overall status of the groundwater quality in each local communities) were conducted in 1,710 cities in fiscal year 1999 and many wells were revealed to be contaminated with trichloroethylene (15 out of 4,455 wells exceeded the standard value and so on) and tetrachloroethylene (23 out of 4,451 wells exceeded the standard value and so on). Especially, for the nitrate nitrogen and nitride nitrogen added in Environmental Quality Standards for Groundwater in February 1999, 173 out of 3,374 wells exceeded the standard value. From the survey with questionnaire sent to the prefectural governments, 1,794 cases of groundwater pollution were reported in Japan as of the end of fiscal year 1999.
 Water Quality Monitoring Systems
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| Present Status of Countermeasures |
Since the most important countermeasure is to prevent the groundwater pollution beforehand, the Ministry of the Environment amended the Water Pollution Control Law in June 1989 to stipulate prohibition of infiltrate discharge with toxic substances and monitoring of groundwater by prefectural governments. The Water Pollution Control Law was also amended in May 1996, and this amendment stipulates that the prefectural government can order the polluters to purify the contaminated groundwater.
To promote the countermeasures against the groundwater pollution efficiently and effectively, a set of procedures from survey to countermeasures with respect to pollution of soil and groundwater, must selectively be determined. To this end, the Ministry of the Environment completely amended the guidelines prepared in fiscal year 1994 to “Guideline: Survey and Countermeasures for Pollution of Soil and Groundwater” in January 1999 and published detailed operational guidelines.
With addition of three environmental health matters such as boron in November 1999, three substances (“boron and its compounds”, “fluoride and its compounds”, and “ammonia, ammonium compounds, nitrate compounds and nitrite compounds”) were added to toxic substances. (Date of enforcement: July 1st, 2001)
Since the nitrate nitrogen and nitrite nitrogen need different countermeasures depending on the area, those countermeasures specific to the local characteristics and nationwide uniform countermeasures must be implemented effectively, taking account of various pollutant properties, and effective countermeasures.
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| Establishment of Environmental Quality Standards for Groundwater |
Groundwater, which has constant temperature and good quality, is not only used as familiar water resources, but also important to keep a sound water cycle. At present, about 30% of water for the urban activity comes from groundwater.
To develop the comprehensive conservation of groundwater quality, the environmental quality standards for groundwater were established based on the Basic Environmental Law Article 16 in March 1997.
These standards are applied to all groundwater and 26 items, which are the same as those defined as public water environmental health matters, have been effective under the same standard values (nitrate nitrogen and nitrite nitrogen, fluorine, and boron were added in February 1999). Since these materials might affect the human health, it was determined that the standard values had to be met as soon as possible and maintained. The policy for conservation of groundwater quality aims at attainment and maintenance of these standard values.
Environmental Quality Standards for Groundwater Pollution |
