Jump to the beginning of content

LCQ3 : HK's treated water complies with WHO guidelines

Following is a question by the Hon Fred LI Wah-Ming and an oral reply by the Acting Secretary for Works, Mr Keith Kwok Ka-keung, in the Legislative Council meeting today (May 22) :

Question:

It has been reported that in some of the samples drawn from Dongjiang water and the sources of Hong Kong reservoirs, the Open University of Hong Kong had detected the presence of parasites originated from animal wastes, and the Water Supplies Department ("WSD") had also detected the presence of cryptosporidia in treated potable water. Two years ago, WSD undertook to release information on water quality in relation to cryptosporidia through the internet but it has not done so. In this connection, will the Government inform this Council :

(a) of the test items and results of the regular water quality tests conducted by WSD on the quality of water from Dongjiang and the sources of Hong Kong reservoirs over the past three years, including the per litre content level of each of those tested items;

(b) of the test items and results of the tests conducted by WSD on treated and filtered potable water over the past three years; and whether such test results have shown that potable water in Hong Kong meets the international safety standards of potable water; and

(c) whether WSD will consider releasing the test results on the quality of potable water regularly; if so, of the details; if not, the reasons for that?

Answer:

(a) The Water Supplies Department has a comprehensive monitoring programme for raw water. Water samples (including Dongjiang water and reservoir storage) are taken regularly from catchments, impounding reservoirs and water treatment works. As Dongjiang water accounts for about 80% of our raw water, the WSD monitors the Dongjiang water quality at Muk Wu Pumping Station, the reception point in Hong Kong, on a 24-hour basis for the sake of understanding the water quality and fine-tuning the treatment processes. The WSD also has stringent testing and monitoring on the quality of water in reservoirs.

Over the past three years, the test items and the concentration of these items for Dongjiang water are given in Annex 1.

According to the results of comprehensive testing by the WSD, Dongjiang water and the water in reservoirs are both suitable for use as raw water. In other words, after proper treatment, the treated water will comply with the World Health Organisation (WHO) Guidelines for Drinking-water Quality.

(b) Hong Kong enjoys one of the safest water supplies in the world. The WHO was established by the United Nation. The WSD adopts WHO Guidelines for Drinking-water Quality (1993), which contains 94 parameters, to monitor the quality of drinking water. Samples are regularly taken from the entire water supply network, including treatment works, service reservoirs, watermains and consumers' taps for examinations of the relevant parameters.

Over the past three years, the test items and the concentration of these items for treated water are given in Annex 2.

The treated water in Hong Kong has to go through very comprehensive treatment processes, including sedimentation, filtration and disinfection, to ensure that the treated water quality complies chemically and bacteriologically with the WHO Guidelines for Drinking-water Quality. The treated water in Hong Kong is safe for lifetime consumption.

(c) At the meeting of the Advisory Committee on the Quality of Water Supplies on 19 July 2001, members agreed at the publication of water quality data on the Internet on an annual basis. The WSD first published the Dongjiang raw water quality at Muk Wu and treated water quality data for 1999/2000 via the WSD web-site in August 2000. Subsequently, the water quality data for 2000/2001 were published via the WSD web-site in July 2001. The data for 2001/2002 are scheduled to be published in the WSD web-site in July 2002 in accordance with the annual publication programme. The practice of publishing water quality data on annual basis is in line with international practice as practised in the USA and UK.

The main part of the question has mentioned the publication of water quality data in relation to Cryptosporidia. The WSD has considered this issue two years ago. However, there were some diversified technical views in 2000. Therefore, the WSD has concentrated in the first publication exercise on the 94 parameters of the WHO Guidelines for Drinking-water Quality. As Cryptosporidia is not one of the 94 parameters, the related data were therefore not published.

On April 4, 2002, the Advisory Committee on the Quality of Water Supplies agreed to the inclusion of water quality data in relation to Cryptosporidia in raw water and treated water. When the WSD carries out the next update of water quality data in WSD web-site in July 2002, the test results on Cryptosporidia will also be included.

End/Wednesday, May 22, 2002

NNNN


Back.