Seiko Instruments Inc. (SII) conducted an overall soil pollution investigation of the premises of the Miyakubo facility for its closure and sale. The investigation detected organic solvents (trichloroethylene and cis-1, 2-dichloroethylene) and heavy metal (hexavalent chromium compound) in some of the soil in excess of environmental standards. A number of subsequent in-depth investigations proved that there was no outflow of these pollutants from the site.
SII has already reported the investigation results to the Environment Protection Department of the Ichikawa City, and will voluntarily take appropriate soil purification action with the consent of the administrative authorities concerned.
1. Periods and Results of Investigations
(1) Organic solvents (trichloroethylene and cis-1, 2-dichloroethylene)
SII conducted five investigations. The initial investigation started in March 2006 to check the overall condition of organic pollutants on site. The final investigation was held in December 2006 to confirm the detailed condition of the pollutants. Although most of the facility was within allowable limits, in some areas up to 15 mg/l of trichloroethylene was detected exceeding the standard of 0.03 mg/l. A maximum concentration of 10 mg/l of cis-1, 2-dichloroethylene, which could have been generated from decomposed trichloroethylene, was detected exceeding a standard of 0.04 mg/l. The pollutants were found at depths ranging from approximately 6 to 14 m and 24 to 27 m underground in an area of about 100 m2 on the premises requiring purification.
There had been a trichloroethylene tank in the area where the pollutants were found. SII presumes that the trichloroethylene originated from the tank as a result of leakage. The soil pollution remained on the premises of the Miyakubo facility, and there is no wide area pollution resulting from the pollutants.
(2) Heavy metal (hexavalent chromium compound)
SII conducted two investigations. The initial investigation started in December 2006 to check the overall condition of residual heavy metal on site. The final investigation was held in January 2007 to confirm the detailed condition of the heavy metal pollutant. As a result, a maximum of 52 mg/l of a hexavalent chromium compound was detected exceeding the standard of 0.05 mg/l. The compound was found at a depth of approximately 2m underground in an area of about 1,300 m2 on the premises requiring purification.
Since the use of this substance was not recorded on this site in the past, the cause of its presence is still under investigation.
2. Countermeasures
(1) Organic solvents (trichloroethylene and cis-1, 2-dichloroethylene)
Groundwater is not present in the depth range of 6 to 14 m where the excessive contaminants were found. SII will excavate and remove the soil in the area and backfill the area with soil of good quality. Recycling of the contaminated soil for use as a cement material after detoxification is also being considered. In addition, SII will pump groundwater from the depth of 24 to 27 m, in order to purify the soil.
The removal of the soil will take four months and be completed by the end of June 2007. Then the groundwater will be pumped out in six months.
(2) Heavy metal (hexavalent chromium compound)
Currently, a building exists in the area where the pollutant was detected, and it is difficult to take any countermeasures until the building is demolished. SII will demolish the building around summer 2007, excavate and remove the soil, and backfill the area with soil of good quality. Recycling of the contaminated soil for a cement material after detoxification is also being considered.
These procedures will take approximately three months for completion.
3. Explanation to the Community
SII held an explanation meeting with the local residents on March 9, 2007, to report the status of the soil pollution investigations and environmental improvements. Based on the resident opinions, SII will take appropriate actions with their consent.
As a good corporate citizen, the SII Group continuously strives to protect and improve the environment, attaching importance to the global environment and coexistence and harmony with the local area.
[Miyakubo Unit]
1956 Established as a watch parts production and coating / thermal treatment plant.
1978 Established efficient production system for substrate production and packaging.
February 28, 2007 Closed.
Number of Employees: about 500 in 1960s
Contact Information
Seiko Instruments Inc.
Corporate Communications Dept.
Online Inquiry