Water / Soil / Ground Environment

Conservation of the Water Environment - Chapter 3

3. Conservation of the Water Environment

3. Ground Water Pollution/Present Status and Countermeasures

(1)Status

Groundwater, which has constant temperature and good quality is not only used as familiar water resources, but also important to keep a sound water circulation.

At present, about 30% of water for the urban activity comes from groundwater. Recently, groundwater pollution by trichloroethylene, tetrachloroethylene and other pollutants were revealed. According to the surveys of groundwater's conditions in fiscal 1993, groundwater pollution was detected in 1,151 areas. As a result of the monitoring by prefectural governments, we have known groundwater pollution has been increasing every year.

General groundwater surveys were conducted in 1,498 -municipalities in fiscal 1994. These surveys found groundwater contamination by trichloroethylene (11 out of 3,996 wells in excess of assessment standards, and other pollutants.

(2)Revision of the Water Pollution Control Law

The surveys conducted in the 1980's found the wide-range groundwater contamination in Japan. Based on this survey, the Environment Agency amended Water Pollution Control Law in June 1988 stipulate prohibition to infiltrate discharge with toxic substances and monitoring of groundwater by prefectural government which is subsidized by the Environment Agency. After this amendment, the technology of purification for groundwater reached practical use level and groundwater contamination was still discovered in many areas, the importance of purification of polluted groundwater based on legal system had been pointed out.

In February 1996, the Central Environment Council submitted a report concerning about purification measures in order to present polluting groundwater. Based on this report, the Environment Agency amended Water Pollution Control Law in May 1996. The amended law, which will be enforced in fiscal 1997 stipulated that prefectural governor can order that the polluter purifies contaminated groundwater.

(3)Establishment of Environmental Quality Standards for Groundwater

The Environment Agency established the Environmental Quality Standards for groundwater in March 1997, aiming at further promotion of comprehensive conservation of groundwater environment. This Environmental Quality Standards is applied to all of groundwater, and the same standard values are established as the standard for protecting human health with the 23 substances of the EQS for public water resources. It was established to "make every effort to be attained and maintained immediately" because it is related to human health. From now on, conservative administration of groundwater is conducted with aiming at the attainment and maintenance of this environmental standard.

FY1996 Survey Conclusion

ItemSampleExceeded
Sample
Rate of
Exceed
Standard Values
cadmium 2,100 0 0.00 0.01 mg/liter or less
total cyanogen 1,899 0 0.00 in no detectable amounts
lead 2,483 7 0.30 0.01 mg/liter or less
chromium (VI) 2,306 0 0.00 0.05 mg/liter or less
arsenic 2,648 43 1.60 0.01 mg/liter or less
total mercury 2,082 1 0.05 0.0005 mg/liter or less
alkyl mercury 801 0 0.00 in no detectable amounts
PCB 1,196 0 0.00 in no detectable amounts
dichloromethane 2,904 0 0.00 0.02 mg/liter or less
carbon tetrachloride 2,920 3 0.10 0.002 mg/liter or less
1,2-dichloroethane 2,856 0 0.00 0.004 mg/liter or less
1,1-dichloroethylene 2,907 1 0.03 0.02 mg/liter or less
cis 1,2-dichloroethylene 2,854 2 0.10 0.04 mg/liter or less
1,1,1-trichloroethane 3,786 0 0.00 1.0 mg/liter or less
1,1,2-trichloroethane 2,846 0 0.00 0.006 mg/liter or less
trichloroethylane 3,867 5 0.10 0.03 mg/liter or less
tetrachloroethylene 3,864 18 0.50 0.01 mg/liter or less
1,3-dichloro propane 2,572 0 0.00 0.002 mg/liter or less
thiram 2,405 0 0.00 0.006 mg/liter or less
simazine 2,380 0 0.00 0.003 mg/liter or less
thiobencarb 2,377 0 0.00 0.02 mg/liter or less
benzene 2,618 0 0.00 0.01 mg/liter or less
selenium 2,230 0 0.00 0.01 mg/liter or less

Preservation of Drinking Water Sources

(1) Pollution of Drinking Water Sources

Of all drinking water sources, surface river and stream water accounts for about 70% and is greatly influenced by water pollution. Underground sources account for about 30% and have begun to exhibit the pollution by trichloroethylene. There were 52 drinking water utilities which were affected by the pollution of the drinking water sources fiscal 1993. Besides, recently eutrophication in the reservoirs, etc. has brought about the excessive propagation of the algal, etc. leading to the unpleasant odor or taste of tap water. There were 80 drinking water utilities which supplied the drinking water of the unpleasant taste, and the number of the people affected were about 14,130,000.

The drinking water utilities are trying to maintain the safety of the drinking water by introducting advanced water purification facilities and so on. This turns out to be a heavy burden for the utilities and becomes one of the factors for the rise of the water purification and processing cost.

(2)Countermeasures for Drinking Water Sources

"The Law Concerning Special Measures for the Preservation of Water Quality in Headwaters Areas for the Purpose of Preventing Specific Trouble in the Drinking Water Supply" was enacted in February 1994 and enforced on May 10, 1994. An organic chlorine compound (trihalomethane), which is generated as a by-product in the process of purifying raw water for drinking, and is regarded as carcinogenic, has, in recent years, been discovered in drinking water and is considered to exceed the Water Quality Standards for drinking water.

The new law stipulates that the government should determine the basic policy for the preservation of water quality in headwaters areas for the purpose of preventing the trouble in the drinking water supply by the substance generated secondarily in the process of raw water purification, and that the prefectural governors should make a water quality preservation plan, by which quality preservation projects and water contamination prevention regulations and other measures should be taken comprehensively and systematically, in the headwaters and areas designated by the prime minister.

This law stipulates that the government should determine the basic policy for the preservation of water quality in headwaters area for the purpose of preventing the trouble in the drinking water supply by the substance generated secondarily in the process of raw water purification, and that the prefectural governors should make a water quality preservation plan, by which quality preservation projects and water contamination preservation projects and water contamination prevention regulations and other measures should be taken comprehensively and systematically, in the headwaters and areas designated by the prime minister on the basis of the applications from prefectural governors.

Comprehensive measures are set forth, including projects conducive to the preservation of water quality as a countermeasure against household sewage and regulations to control waste water from plants and business establishments in order to achieve the water quality target level, which is determined in the water quality plan.

Legal system to Take Special Measures for The Preservation of Water Quality in Headwaters Areas for The purpose of Preventing specific Trouble in The Drinking Water Supply

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