XN000022-1996-08-29 — Page 20

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The grading of some beaches may vary during the summer. This represents a natural fluctuation in the bacteriological quality of bathing waters in most cases, as rain and tides bring more or less pollution to the beaches.

However, the grades give a good general picture of the water quality at bathing beaches at the time of reporting and form the best available forecast for the immediate future.

Beaches with highly developed hinterlands are likely to be more polluted than the grades suggested during and after heavy rain.

"Bathers should avoid such beaches for two or three days after a storm, longer if the weather remains overcast or less if there is strong sunshine," Principal Environmental Protection Officer, Mr Patrick Lei said.

The system for grading beach water quality is as follows:

Grade "1" indicates that the water quality is good. The E coli count is no more than 24 per 100 millilitres at each beach so graded, and the expected risk of minor illness to swimmers is undetectable.

Grade "2" indicates that the water quality is fair. The E coli count is no more than 180 per 100 millilitres at each beach so graded, and the expected health risk is no more than 10 cases of minor illness per 1,000 swimmers.

Grade "3" indicates that the water quality is poor. The E coli count is no more than 610 per 100 millilitres at each beach so graded, and the expected health risk is no more than 15 cases of minor illness per 1,000 swimmers.

Grade "4" indicates that the water quality is very poor. The E coli count is more than 610 per 100 millilitres at each beach so graded, and the expected health risk is more than 15 cases of minor illness per 1,000 swimmers.

The decision whether or not to close a beach to swimmers is based on a judgement of what degree of pollution is acceptable.

Normally, the closure of a beach would only be considered by the Urban or Regional Council if a grade "4" occurred repeatedly, so that the average health risk over the bathing season exceeded 15 cases per 1,000 swimmers.

At present five gazetted beaches, namely Anglers', Approach, Castle Peak, Rocky Bay and Ting Kau, are closed to swimmers, while Old Cafeteria is re-opened.

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