XN000022-1995-05-03 — Page 55

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Volatile organic chemicals in drinking water

The following is a question by Dr the Hon Huang Chen-ya and a written reply by the Secretary for Works, Mr James Blake, in the Legislative Council today (Wednesday):

Question:

Given that the chemical solvent tetrachloro-ethylene has been found to cause leukaemia and bladder cancer, will the Government inform this Council of the respective levels of the following volatile organic chemicals:

tetrachloroethylene

trihalomethanes

(a)

0000

(b)

(c)

benzene

(d)

dichloroethylene

(e)

dichloroethane

detected in the territory's drinking water in the past five years?

Reply:

Mr President.

The Water Supplies Department carries out extensive quality monitoring of treated water supply in Hong Kong on an on-going basis in accordance with the recommendations as set out in the World Health Organization's (WHO) Guideline Values for Drinking Water Quality.

Over the past five years, more than 1500 water samples have been taken from the supply and distribution network including consumer taps for analysis of trace of organics with the aid of sensitive analytical instruments. The monitoring records indicated that the concentrations of tetrachloroethylene, trihalomethanes (chloroform, bromoform, dibromochloromethane and dichlorobromomethane), benzene, 1,1- dichloroethene, 1,2-dichloroethene and 1,2-dichloroethane in treated water supply were consistently well below the guideline values laid down by the WHO. According to WHO the concentrations of these organic compounds in drinking water at such levels should not pose any threat to public health over a lifetime consumption.

End/Wednesday, May 3, 1995