Countermeasures for PCBs Taken by Hyogo Prefecture

（ Takasago West Port ）

Hyogo Prefectural Government Agricultural and Environmental Affairs

Dept. Environmental Management Bureau,

Water and Air Quality Control Division 　　　　　　　　　　　　　　　　　

Kotoko UENISHI

2

What are PCBs PCB stands for Poly Chlorinated Biphenyl, a class of poly

chlorinated compounds. Theoretically 209 isomers exist depending on the number of chlorine atoms in the molecular and substituent positions. Particularly Coplanar PCB (coplanar means shapes, structures that lie on the same plane) is extremely toxic and belongs to the class of so-called Dioxins.

PCBs are chemically stable compounds, having low water solubility, high boiling temperature, hardly degradable by heat, and non-burnable as well as electrically insulated. Therefore, they had been widely utilized as insulating oil for electrical equipment and heat catalyst for heat exchanger as well as carbonless paper.

Since PCBs have superior characteristics such as insulating (preventing electricity from passing through), and incombustible (hardly burn), they have been used for a wide variety of products including electrical equipment such as trans-condenser

When Kanemiyusho (Kanemi rice oil disease) incident occurred in 1968, growing social attention had been paid to their toxicities and the use of PCBs had come to a social issue. As a result, the manufacturing of PCBs was banned in 1972

１　 Great attentions had been paid to PCBs inspired by Kanamiyusho (Kanemi rice oil disease) incident. This incident was caused by PCBs, etc. that were used as heat catalyst and accidentally mixed into rice oil during a deodorization process.In October of 1968, food poisoning caused by rice oil broke out in wide areas with a focus on the west Japan. The number of patients were estimated to be about 13,000.

２　 General symptoms of PCB poisonings such as eye mucus, pigmentary deposit on nails and oral cavity membrane as well as chloro-acne, deformation of nails, swelling of eye lids and joints are reported.

Deodorization process for rice oil

Kanemi rice oil incident

heating

a holeRice oil

1968Kanemiyusho (Kanemi rice oil) disease incident

1972 ～PCBs surveys for bottom sediments in coastal seas and rivers carried out throughout the country

1972PCBs contamination was found in the bottom sediments dredged from Takasago West Port

PCB Contaminations in Takasago West Port

Dredging in Takasago West Port (1974 ～1975)

The details of the treatment of PCB-containing bottom sediments

　　１　 PCB-containing bottom sediments piled up in the port were dredged and

solidified, then, banked in the area owned by the alleged manufacturing company.

　①　 The 1st phase of construction: September, 1974 ～ March, 1975　　　 The 2nd phase of construction: August, 1975 ～ August, 1976　②　 Amount of the dredged soil: 301,000 ｍ３

　③　 Amount of banked soil: 283,000 ｍ３

　　　（ Dredged & solidified soil 224,000 ｍ３ , Amount of covering soil 59,000ｍ３）

　④　 Area for banking: 51,000 ｍ２

　　２　 The surface and the bottom of the banked area were covered by

asphalt, and the area has been controlled completely cut off from outside areas.

Survey results for PCBs contained in bottom sediments in the Takasago West Port

　１ 　 Bottom sediment survey before dredging （ June, 1972 ～ April, 1973 ）　　　　　 19 survey points Maximum 3,300ppm ～ Minimum 20ppm

　２　 Bottom sediment survey immediately after dredging （ January, 1976 ）　　　　　 40 survey points ４ cross points Average value 4.53ppm ～

0.02ppm　　　　（ Tentative removal standard for bottom sediments: 10ppm ）

PCB related standardsParameters Standard values, etc. Remarks

Water quality

Environmental standards regarding water pollution

-Not detected（＜ 0.0005mg/L ）

Environmental Basic LawEnvironmental standards regarding groundwater

-Not detected（＜ 0.0005mg/L ）

Effluent standards

- 0.003mg/L Water Pollution Control Law

Tentative removal standards for bottom sediments

　 content 10 ｐｐｍNotification made by Director General of Water Quality Preservation Bureau, Environment Agency in 1975

Environmental standards with regard to soil pollution

　 elutionNot detected（＜ 0.0005mg/L ）

Environmental Basic Law

Standards with regard to specification of soil pollution (standards for elution volume)

　 elutionNot detected（＜ 0.0005mg/L ）

Soil Contamination Countermeasure ActStandards with regard to actions for removal of polluted soil, etc. (The 2nd standards for elution volume)

　 elution 0.003mg/L

Standards with regard to judgment for industrial wastes (sludge)

　 elution 0.003mg/LLaw Concerning Waste Treatment and Clean-up

Concentrations in the atmosphere (guideline values)

　 － 0.05μg/m3

Tentative allowable limit for PCBs release in exhaust gas when PCBs are incinerated (Notification by Director General of Atmospheric Preservation Bureau, Environment Agency in 1972 ） . Guidelines regarding treatment and disposal of bottom sediments（ Notification by Director of Water Environment Dept. , Ministry of Environment in 2002 ）

Takasago West Port in 1980

400m

100m

Restoration and improvement ofTakasago West Port

③ 　 Enhance accessibilities

④ 　 Create water-front park

① 　 Enhance Port functions

② 　 Permanent protective measures and

effective utilization strategies for

the bank

Permanent protective measures for banking site

PCB-containing solidified soil

Carbide scum, bank （ sand, gravel ）

Sandy soil

Clay （ non-permeable layer ）

Non-permeable underground soil retaining wall

Reinforced

protective wall

Surface

cover

Sea

PCB Surveys for Atmosphere and Water

PCB survey for atmosphere and water (Takasago city, Hyogo prefecture & related companies)

○Atmosphere

○Rain water

○Ground water

○Sea water

●Continuous monitoring of public water bodies

○○○○PCB tracing survey by Takasago city and companies (twice a year) ●Continuous monitoring by Hyogo Prefecture (4 times a year)

All the measured values have been below quantitation limit since 1976.

For banking

Dredging

Takasago West Port

Landfill

PCB Survey for Bottom Sediments

PCB survey for bottom sediments (Takasago City) once a year

All the survey points have shown PCB concentrations below tentative removal standards for PCB

For banking

LandfillDredging

Takasago West port

Thank you very much for your kind attention