Heavy metals and toxics found in CLP’s fly ash

Press release - 2005-10-03
Greenpeace found toxic heavy metals, namely mercury and arsenic, in the fly ash produced by China Light and Power (CLP). Both mercury and arsenic have not been completely captured by the existing pollution control devices, a prolonged exposure to which would put people’s health at risk.

Greenpeace members collected samples of fly ash in CLP’s lagoon in Lung Ku Tan and a cement factory in June and July this year. The samples were sent to an accredited laboratory in UK for analysis.

Greenpeace demands the two local electric companies to stop burning coal and releasing toxic heavy metals and the companies should also make concrete plan for development of renewable energy, and to guarantee meeting the emissions reduction target set by Hong Kong's Environmental Protection Department. It bids the SAR government to review the existing Air Quality Objectives (AQO) by including heavy metal toxics into the air pollutants monitoring list. Moreover, the SAR administration has to oblige the electric companies to implement the emission reduction target for improving Hong Kong air quality.

Greenpeace members collected samples of fly ash in CLP's lagoon in Lung Ku Tan and a cement factory in June and July this year. The samples were sent to an accredited laboratory in U.K for analysis. The report shows that all samples contain toxic mercury and carcinogen arsenic. Estimated from the amount of fly ash produced by CLP in 2004, an annual production of mercury and arsenic are approximately 36.4kg and 14,000kg respectively.

According to Greenpeace's report, the two heavy metals cannot be completely captured by the power plants' existing control devices. Up to 30% of arsenic and 95% of mercury can be emitted into the air.[i] Greenpeace campaigner on air pollution Chow Sze-chung stressed that the mercury and arsenic found in fly ash could not be eliminated by our nature and will be accumulated in the environment.

Chow further pointed out, "heavy metals cause serious environmental pollution and put human health at risk. Prolonged exposure to mercury will result in the accumulation of the substance in the body and destroy the central nerve system, kidneys and developing foetus (in the case of pregnant woman). Arsenic is carcinogenic. Prolonged exposure can cause skin and liver cancers, destroy human vascular system and nervous system."

Greenpeace also found out that the existing AQO in Hong Kong has not included mercury and arsenic in the air pollutants monitoring list.

Chow pointed out that "Hong Kong does not have a comprehensive monitoring system on air pollutants. It is outdated and loose compared with international standard. In fact, EU and the State of California (U.S) have included arsenic into their standards; as for mercury, World Health Organization (WHO) and California also have it measured regularly."[ii]

The toxic element arsenic is a composite of Respiratory Suspended Particles (RSP), a major pollutant that the Environmental Protection Department has demanded the two electric companies to reduce in emission. In 04-08 financial plans of China Light and Power (CLP) and Hong Kong Electric (HEC), in spite of the estimated 3% annual growth in power supply, both companies state that they could not meet the pollution emission target and that they have no single plan to reduce the emission of RSP.

Chow warned, while the government is not running regular monitoring of these toxic air pollutants, the power companies are expanding in their emission, people's health is thus left in unacknowledged danger.


Mr. Chow Sze-chung, Greenpeace campaigner +852-28548332
Ms. Ho Leun, Greenpeace media officer +852-28548326


[i] See Kotnik J., Horvat M. , Mandic V., Logar M., (2000) Influence of Sostanj coal-fired power plant on mercury and methyl mercury concentrations in Lake Velenje, Slovenia. The science of total environment, 259:85-95,及Llorens J. F., Fernandex-Turiel J.L., Querol X. (2001) The fate of trace elements in a large coal-fired power plant. Environmental Geology, 40(4-5): 409-416.

[ii] See “Assessment of toxic air pollutants measurements in Hong Kong, 2003” http://www.epd.gov.hk/epd/english/environmentinhk/air/studyrpts/files/tapfr1.pdf