Soil Contamination Countermeasures Hyogo Prefectural Government Agricultural & Environmental Affairs Department Environmental Management Bureau Water & Air Quality Control Division Water Quality Group IINO Hiroo 飯野 博夫 JICA Training

Contents 1 VOC (Volatile Organic Compounds) contamination countermeasures (Plants) 2 Heavy metal contamination countermeasures (urban area)

2 ○ VOC( Volatile Organic Compounds) contamination spreads out deep into the ground, contaminates the underground water and lasts for a long time ○ Heavy metal contamination remains in the surface layer but sometimes it is difficult to differentiate the nature- derived and artificial ones ○ Once the land is contaminated, remediation measures take a lot of money and time ○ Soil contamination makes a difference in land price (Once soil contamination is found, the land value is estimated as almost zero) Summary of soil contamination countermeasures

3 Difference made in soil contamination by substances ・ VOC contamination spreads out deep into the ground and contaminates the underground water ・ Heavy metal contamination remains in the surface layer Most heavy metals Volatile organic compounds aquifer Hardly-permeable layer

4 〔The beginning of the revelation of contamination〕 1983 The Ministry of Health and Welfare ordered all prefectures to investigate water supply for TCE (Trichloroethylene) etc. Oihara 0.407mg/L, Okidai 0.076mg/L （ WHO guideline 0.03mg/L ） 1 VOC (Volatile Organic Compound) contamination countermeasures (Plants) 〔Water supply source problem〕 Dec Stopped water supply from the source of the area Adjacent cities supported by supplying water from their source Jan.～1984 Installed purification (aeration) apparatus to the source 〔Underground water investigation〕 Dec.～1983 Conduct well water survey in the neighborhood （Maximum concentration 10mg/L） Jan.～1984 Transfer of households using well water to public water system

5 Distribution of Trichloroethylene concentration (unit: ppb) Jan – March 1984 Manufacturing CRT (cathode ray tube) Usage of TCE ・ Amount Monthly 12 – 14t ‘( Annually t) ・ Period From 1970 to 1983

Contaminated soil remediation work (excavation process） Apr. ～ June 1984 Excavated and removed about 1,000m 3

7 Chronological change of distribution of soil contamination 〔 Monitoring investigation of the neighborhood 〕 ・ Chose 20 typical wells as fixed point observation and conducted follow-up investigation ・ The spread of contamination rapidly declined after the removal of the contaminated soil

8 Chronological change of Trichloroethylene concentration in shallow and deep wells in the plant 〔 Countermeasures taken in the plant 〕 Feb.1984 Switched from Trichloroethylene to 1,1,1-Trichloroethane Later ・ Started to pump contaminated wells （ shallow wells & deep wells ） ・ Trichloroethylene concentration declined after switching the raw materials ・ Trichloroethylene concentration declined rapidly after the removal of contaminated soil Removal ofcontaminatedsoil shallow well Deep well Switch materials TCE concentration

9 Changes of Trichloroethylene concentration in deep wells 〔Countermeasures taken at deep wells〕 ・The highest concentration measured is about 6mg/L at the latest survey ・The concentration of other deep well is declining due to pump water

○ The excavation of contaminated soil and pump underground water methods were effective for shallow wells inside and outside of the plant ○ However, decline is slow for the concentration of deep wells in the plant and maintains the high level around 6mg/L as in the latest survey ○ Lot of time and labor is necessary to remediate once contaminated soil & underground water. This reminds us of the difficulties of solving this problem 10 Summary & Challenges

11 2 Heavy metal contamination countermeasure (Urban area) ・Kawanishi city is located in the metropolitan area and its suburbs like Osaka or Kobe ・Central North Area is situated in the center part of the city （Area about 24ha） ・ The area expanded once thanks to the local leather industry but now it is in decline Future initiatives toward redevelopment Kawanishi Central North Area Osaka Kobe

12 Jan.1983Mar Central North Area（Full view）

13 Image of Redevelopment of Central North Area A bird’s eye view Seseragi no michi (A path along a shallow) (provisional name)

14 〔Soil Contamination Investigation〕 In the past Used hexavalent chromium at leather plants Feb.2003 Enforced Soil Contamination Countermeasures Law ○ Close the plants before law enforcement → exempt from this law（ No obligation for investigation ） ○ Close the plants after law enforcement → subject to this law ( Obliged for investigation ) ※ It is necessary to make clear the current contamination condition for the future site substitute hereinafter → Gave guidance to conduct voluntary survey in accordance with the law for the areas both within and out of the range of law enforcement and to increase the number of items to be analyzed

15 Soil Investigation Results (Kawanishi city & business operators) ・ As a result of investigation of about 97,000m 2, about 18,630m 2 was contaminated in area ・ Target substances were Hexavalent Chromium compounds, Lead, Arsenic, Fluorine and Boron and their compounds ・ No contamination was detected in the water quality survey of underground and water way in the area ・ Countermeasures like excavation & removal etc. were taken for soil estimated to be contaminated artificially Soil investigation points

16 1 Conduct soil contamination status investigation of areas not surveyed yet 2 Before conducting site substitute in redevelopment projects etc., be sure to trace back the history of soil contamination and usage still farther (There are cases that current residential house used as plant using hazardous substance in the past) 3 The heavy metal soil contamination of this area is difficult to identify the source of pollution; nature-derived or artificial Problems and Challenges