An environmental group yesterday criticized a clean-up plan for the former site of a notorious chemical plant in Anshun (安順), Tainan City, as inadequate, saying that the most stringent standards must be employed for the site, which has the highest known soil dioxin levels in the world, and that it should be closed off until better technology is available.
Two days before an expert panel was to conduct a second review of the project to clean up the site, Green Formosa Front Taiwan chief executive Wu Tung-jye (吳東傑) called on the panel to “stringently guard the soundness of the protocol and not let China Petrochemical Development Corp [CPDC] off lightly.”
The plant was built by the Japanese in 1942 to manufacture caustic soda solids, hydrochloric acid, liquid chlorine and poisonous gases for military use.
CPDC later took over operations of the plant.
A court recently ruled that CPDC was responsible for cleaning up the land, Wu said, because the soil is now heavily laced with mercury, pentachlorophenol and dioxins, which are carcinogenic.
“However, for dealing with such extensive pollution, the proposed cleanup method is very sloppy and incomprehensive,” he said.
“The polluted area covers a total of 36 hectares,” Wu said.
“The highest dioxin level measured in the soil was 64.1 million ng-I-TEQ/kg [nanograms of international toxic equivalent per kilogram] around the pentachlorophenol factory, which is 64,100 times the [recognized] safety level for soil pollution and a world record high,” he said.
“No current technology is sufficient to clean this up successfully,” he said.
Around the old caustic soda and chlorine factory, the mercury concentration in the soil is 9,550 milligrams per kilogram, or 478 times the safety standard, he said.
“However, CPDC plans to divide the plant into areas of ‘high’ and ‘medium and low’ concentrations, and employ a two-stage cleanup strategy,” Wu said.
CPDC would use a method called temperature-programmed desorption (TPD) on “high” concentration areas — with measurements of 50,000 ng-I-TEQ/kg or higher — but “the highest documented level of concentration that has been treated by TPD was 17.5 million ng-I-TEQ/kg, which is much lower than 64.1 million ng-I-TEQ/kg,” Wu said.
“For areas [with a concentration] between 1,000 ng-I-TEQ/kg and 50,000 ng-I-TEQ/kg, cleanup experiments will be conducted, including vegetation restoration and chemical treatments,” he said.
But Wu said CPDC’s categorizations were its own creation and entirely arbitrary.
“A level of 50,000 ng-I-TEQ/kg is 50 times the safety standard and would be considered high in any other case,” he said.
“As [cleaning the soil by planting] vegetation [to absorb the toxins] would take at least 10 years, it is unthinkable that the company thinks it is okay to expose the air to that amount of dioxins for another decade,” he said.
Wu said his organization suspected that China Petrochemical Development Corp planned to use vegetation restoration and chemical treatments to keep cleanup costs low.
“In Japan’s experience, about NT$30,000 is needed per tonne of soil to remove dioxins,” Wu said.
“If we use that data, the cleanup for the Anshun plant would cost NT$13.3 billion [US$402 million]. Even Tainan Mayor Hsu Tain-Tsair [?]] has said the project would take between NT$5 billion and NT$10 billion,” he said.