Chester Yung – Tuesday, October 04, 2005
Greenpeace charged Monday that CLP Power’s coal-fired power plant in Castle Peak is releasing cancer-causing heavy metals found in fly ash into the atmosphere.
“Two toxic heavy metals-arsenic and mercury – are not on the air pollutants monitoring list under existing Environmental Protection Department’s air quality objectives, which have not been updated in 18 years,” said Greenpeace campaigner Chow Sze-chung, adding that “these elements cannot be eliminated by nature but accumulate in the environment.”
The environmental protest group conceded, however, that CLP’s emissions of heavy metals are lower than those reported for coal fly ash from several other places, including Spain, Greece, Britain and the mainland.
A CLP spokeswoman defended what she called the company’s “comprehensive environmental management and monitoring program” in the production and storage of CLP ash, saying it removes all but a trace of the residues.
Chow urged that CLP stop burning coal altogether and replace it with renewable energy sources.
“Heavy metal causes serious environmental pollution and puts human health at risk,” he said.
Prolonged exposure to arsenic can cause skin and liver cancer, destroy the human vascular system and nervous system. Mercury may accumulate in the body and long-term exposure will destroy the nervous system and kidneys, as well as hurt the development of fetuses.
Chow argued that the Castle Peak plant’s existing control devices are unable to capture the two heavy metals.
“Up to 30 percent of arsenic and 95 percent of mercury can be released to the atmosphere,” Chow claimed.
However, the CLP spokeswoman said “we remove 99.4 percent of the fly ash particles produced in our plant before they get into the air through our electrostatic precipitators.
“We process fly ash in a specially built classification plant to make sure it complies with all the requirements of British Standards, which specifies the chemical and technical properties for the use of fly ash in concrete. We supply fully certified analyses of all our fly ash, meeting the quality requirements of the end users, to verify that it meets this standard.”
On its Web site, CLP said the ash is used in the construction of infrastructure projects, including the Eastern and Western harbor tunnels and the Tsing Ma Bridge. Last year, CLP reported collecting 364 kilotonnes of ash.
The CLP spokeswoman acknowledged that the company sells the ash “at a very low price,” but gave no figures.
“The revenue made from the sale of ash is used to offset operating costs, of which the benefits will be passed on to our customers,” she said.
Greenpeace said it collected six samples of CLP fly ash in the company’s lagoon in Lung Kwu Tan and a cement factory in June and July this year and sent them to the Greenpeace Research Laboratory at the University of Exeter in Britain.
All six samples of coal fly ash, the protest group said, were found to contain heavy metals, while the concentration of these elements – ranging from four to 38 milligrams/kilogram of arsenic and less than 0.1 mg/kg of mercury – were lower than that reported for coal fly ash from the other countries, including European ones, where standards are quite high.
“However, the existence of these toxic elements … to whatever lower level still poses a health hazard to human beings as well as damages the environment,” Chow said.
Based on the amount of ash collected by CLP last year, Greenpeace estimated the plant’s emissions included roughly 36.4kg of mercury and 14,000kg of arsenic.
Chow said Hong Kong does not have a comprehensive monitoring system on air pollutants
“It is outdated and loose compared with international standards,” he said, adding that the European Union and California in the United States have included arsenic in their standards.
An EPD spokeswoman said that major heavy metal pollutants and the relevant operation are regulated by air quality control ordinances and the license requirement.
“The department’s air quality monitoring mechanism managed to control the emission of various heavy metals in a very low level,” she said.
“The limit of arsenic and mercury concentration is 7.11mg/kg and 0.23 mg/kg respectively-which is far below the standard of California in the United States.”
However, Chow said that the EPD still needs to review the existing air quality objectives.