Conservation of soil environment
32 Conservation of Soil Environment 1. Countermeasures for Soil Pollution Since soil plays important roles such as filtration of water quality, groundwater, recharge and production of foods, it is indispensable to protect the soil from contamination and conserve it in proper manner. (1) Environmental quality standards for soil pollution The soil, together with the water and air, is a key component of the environment and plays an important role as basis for living things including human beings and as integral part of the material cycle. Once the soil is contaminated, the impacts last for a long period. Therefore, environmental quality standards are presently defined for 27 items based on the Basic Environment Low. These standards are standards compliance with which is desirable in terms of protecting human health and conserving living envirouments, and reviewed according to the accumulated scientific data on the "as-necessary" basis. The soil environmental quality standards stipulate the elution standard aiming at filtration of water quality and purification of groundwater, and the farmland standard aiming at conservation of food production functions. These two standards are used to judge whether the soil is contaminated or not and give targets for designing the countermeasures against the pollution. ■ Environmental Quality Standards for Soil Pollution Item Environmental quality standards cadmium 0.0lmg/ in sample solution and less* than 1mg/kg in rice for agricultural land total cyanide not detectable in sample solution organic phosphorus** not detectable in sample solution lead 0.0lmg/ or less* in sample solution chromium (VI) 0.05mg/ or less* in sample solution arsenic 0.0lmg/ or less* in sample solution, and less than 15mg/kg in soil for agricultural land (paddy field only) total mercury 0.0005mg/ or less* in sample solution alkyl mercury not detectable in sample solution PCB not detectable in sample solution copper less than 125mg/kg in soil for agricultural land (paddy field only) dichloromethane 0.02mg/ or less in sample solution carbon tetrachloride 0.002mg/ or less in sample solution 1,2-dichloroethane 0.004mg/ or less in sample solution 1,1-dichloroethylene 0.02mg/ or less in sample solution cis-1,2-dichloroethylene 0.04mg/ or less in sample solution 1,1,1-trichloroethane 1mg/ or less in sample solution 1,1,2-trichloroethane 0.006mg/ or less in sample solution。 trichloroethylene 0.03mg/ or less in sample solution tetrachloroethylene 0.0lmg/ or less in sample solution 1,3-dichloropropene 0.002mg/ or less in sample solution thiram 0.006mg/ or less in sample solution simazine 0.003mg/ or less in sample solution thiobencarb 0.02mg/ or less in sample solution benzene 0.0lmg/ or less in sample solution selenium 0.0lmg/ or less* in sample solution fluorine 0.8mg/ or less* in sample solution boron 1mg/ or less* in sample solution * When involving those environmental limits concerning the concentration of cadmium, lead, chromium(VI), arsenic, total mercury, selenium fluorine, or boron in liquid samples, when the soil contamination is alway from the groundwater level and the concentration of the substance dose not exceed 0.01mg, 0.01mg, 0.05mg, 0.01mg, 0.0005mg, 0.01mg, 0.8mg, or 1mg, respectively, in the original condition, then the limit per 1 liter of liquid sample shall be 0.03mg, 0.03mg, 0.15mg, 0.03mg, 0.0015mg, 0.03mg, 2.4mg and 3mg respectively. ** Organic phosphorus means parathion, methylparathion, methyldimeton, and EPN. Note: The above standards are not applicable to (1) the soil in those places where natural toxic substances exist such as the vicinities of mineral veins and (2) the soil in those places designated for storage of toxic materials such as waste disposal sites with respect to the items listed in the above table. 33 (2) Agricultural land soil pollution control measures The soil pollution is one of the oldest pollution types and the agricultural land soil pollution in the Watarase River Basin area generated social concern around 1877. In 1968 "Itai-Itai disease" in the Jinzu River Basin area proved to be a case of chronic cadmium poisoning and again generated social concern to the agricultural land soil pollution problem. Finally, in 1970 the Agricultural Land Soil Pollution Prevention Law was enacted and remedial projects by methods such as clean soil dressing were initiated. Cancellation of designated special area Implementation of special land improvement work for environmental pollution prevention/removal Cancellation of designated agricultural land soil pollution policy areas Planning of cost-bearing plan (Pollution Control Public Works Cost Allocation Law) Request for Application of Financial Special Measures Law (Law on Special Financial Arrangement by the Government for Public Pollution Control Projects) Implementation of measures against polluters ・ Water Pollution Control Law ・ Air Pollution Control Law ・ Mining Safety Law ・ Law on Special Measures for Mine Damages Caused by the metal mining industry, etc. Designation of special area Implementation of Survey of Policy Area Planning of agricultural land soil pollution policy project - Detailed survey for planning countermeasures - Survey for confirming the result of project Prefecture (Subsidy of MOE) Prefectures (Subsidy of MOE) Prefectures, municipalities (Subsidy of MAFF) Prefecture (Subsidy of MOE) Prefectural Governors: Article 8 of the Law Prefectural Governors: Article 9 of the Law Prefectural Governors: Article 4 of the Law Prefectural Governors: Article 5 of the Law Prefectural Governors: Article 3 of the Law Consent of Minister of the environment and Minister of agriculture, forestry and fisheries Report to Minister of the environment [Agricultural Land Soil Pollution Prevention Law] (Law No.139 of December 25, 1970) Central Environment Council Possible polluted area (Inquiry) (Report) (1) Designation of specific harmful substances (Cd, Cu, As) (2) Establishment of requirements for designation of policy areas Designation of agricultural land soil pollution policy areas Fact-finding survey of possible polluted area Fact-finding survey of soil pollution Surveillance and monitoring for recurrence of pollution Report to Minister of the environment Recommendation for planning of specific farm products ■ System of Implementing Agricultural Land Soil Pollution Control Measures 34 ■ Progress in Recognizing and Restoring Sites (3) Urban type soil pollution control measures In 1975, a large quantity of soil contamination with hexavalent chromium was found in Tokyo and it became a serious social problem. Since then, the number of so-called "urban" type soil pollution cases discovered has been rapidly increasing throughout Japan mainly due to accelerated urban redevelopment of sites such as those of former factories and the installation of groundwater quality monitoring activities required by the Water Pollution Control Law. The major soil polluters are the chemical and electroplating industries and the major contaminants are lead, arsenic, and trichloroethylene. ■ Discovered Number of Urban Type Soil Pollution Cases (1) Area of site exceeding EQS 7,156ha (2) Designated site area 6,266ha (3) Planned site area 6,181ha (4) Restored site area 5,818ha (5) Area to be cleaned in the future 1,338ha (ha) '70 '71 '72 '73 '74 '75 '76 '77 '78 '79 '80 '81 '82 '83 '84 '85 '86 '87 '88 '89 '90 '91 '92 '93 '94 '95 '96 '97 '98 '99 '00 (FY) 0 20 40 60 80 100 120 140 160 180 200 Establishment of soil environment standards Number of events exceeding the standards Number of survey events Addition of soil environment standard items FY O n and before 1974 '75 '76 '77 '78 '79 '80 '81 '82 '83 '84 '85 '86 '87 '88 '89 '90 '91 '92 '93 '94 '95 '96 '97 '98 '99 Number of survey events 2 7 6 2 10 5 3 10 2 17 10 18 12 16 23 20 26 38 34 43 44 44 56 58 197 183 Number of events exceeding the standards −−−−−− − − −− −− − − − −− 8 12 13 26 36 50 47 122 117 Number of events 35 ■ Number of Events Exceeding the Standards Per Substance (Accumulation) 2. Survey and Policy Planning of Soil and Groundwater Pollutions With respect to the soil pollution (caused by the pollutants except for dioxins) in the urban area, the business owners have been taking voluntary activities according to the Survey and Countermeasure Guidelines for Soil and Groundwater Countamination enacted in January 1999. Each business owner is required to survey the soil whenever it modifies the land properties and, if it is proved that the soil fails to comply with the environmental quality standards, take any necessary action so that the soil will meet the standards. 120 102 64 55 29 28 15 7 1 140 110 79 17 16 14 13 10 9 7 2 0 20 40 60 80 100 120 140 160 Elution standard item Number of events Heavy metals VOC Lead Arsenic Chromium (VI) Total mercury Cadmium Total cyanide Selenium ＰＣＢ Thiobencarb Trichloroethylene Tetrachloroethylene Cis-1,2-dichloroethylene 1,1-dichloroethylene Carbon tetrachloride 1,2-dichloroethane 1,1,1-trichloroethane Benzene Dichloromethane 1,1,2-trichloroethane 1,3-dichloropropene Discovery of pollution Document survey of subject area (fact-finding) Prefectural governments General Survey of subject area Countermeasures Guidance Detailed survey of subject area Report Guidance Guidance Guidance Guidance (Temporary measures is needed when permanent measures cannot be taken immediately) ■ Outline of Technical Guideline of the Ministry of Environment (Survey and Guideline Contermeasure for Soil and Groundwater Contamination enacted in January 1999) - The Ministry of Environment notifies prefectural governments of the guidelines. - Content The Guideline stipulates the techniques on how to develop surveys and countermeasures in handling of heavy metals (such as cadmium) and volatile organic compounds (such as trichloroethylene) so that these techniques will be helpful to implement surveys and countermeasures for soil and groundwater pollutions. (1) Survey procedure and evaluation of result The Guideline defines three survey phases: document survey, general survey, and detailed survey. (2) Techniques The Guideline describes the techniques for use in countermeasures and summarizes their availability. (3) Surrounding environment conservation and monitoring techniques The Guideline describes the necessity of scattering and discharge preventive measures and monitoring of surrounding groundwater. (4) Communication with prefectural governments If the land administrator discovers the pollution of soil and/or groundwater through the voluntary survey, it shall report the fact to the appropriate prefectural government(s). (5) Preparation and control of records The Guideline stipulates the necessity of preparing and controlling the records which state the situation of pollution and countermeasures. ■ Excavation of Polluted Soil ■ Flow of Guideline-based Survey and Countermeasures . (FY) 0 20 40 60 80 100 120 140 160 180 200 Establishment of soil environment standards Number of events exceeding the standards Number of survey events Addition of soil environment standard. Governors: Article 3 of the Law Consent of Minister of the environment and Minister of agriculture, forestry and fisheries Report to Minister of the environment [Agricultural