2.1 Purposes of Monitoring

The demand for beach water quality information for various purposes has been increasing and the role of monitoring has become more important in recent years. The current monitoring programme has been designed to serve various purposes, which are depicted in Figure 2.1 and summarized as follows:

• To assess compliance with the WQO: Based on the monitoring information, the Authority will be able to determine whether the standard for bathing water is being met.
• To detect any change in beach water quality: Monitoring can provide early warning of beach water pollution so that any potential pollution problem can be attended and resolved more easily at an early stage.
• To identify polluted beaches that need remedial actions: Based on the monitoring results, the Authority can identify polluted beaches and set priorities to take remedial actions for improving the beach water quality.
• To evaluate pollution abatement programmes: Monitoring provides the information needed to determine the efficacy of beach-related improvement measures such as provision of sewerage or enforcement of relevant legislation.
• To decide on the opening of beaches: Monitoring provides the information on water quality trends for gazetted beaches so that the beach management authority can decide on the opening of beaches during the bathing season.
• To advise the public on the beach water quality status: Monitoring helps to answer such question from the public as "Is the beach suitable for swimming?".
  

2.2 The Monitoring Programme

The current beach water quality monitoring programme covers all 41 gazetted beaches and 9 selected non-gazetted beaches (Figure 2.2). Those selected non-gazetted beaches are either popular (e.g. Discovery Bay Beach) or have the potential to be gazetted (e.g. Lung Mei Beach). There were little changes in the gazettal status of beaches over the last 15 years. These changes included the gazettal of the Butterfly and Golden beaches in Tuen Mun and de-gazettal of the Campers and Pak Sha Chau beaches in Sai Kung.

Figure 2.2	Location of beaches in Hong Kong

The monitoring programme had been reviewed and revised several times since its implementation in 1986 with the objective to provide more comprehensive beach water quality information for various purposes. The changes made to improve the monitoring programme are summarized in Table 2.1.

Table 2..1	Milestones of the Beach Monitoring Programme

Monitoring Protocol

All gazetted beaches are now monitored at four to six times per month during the bathing season while the non-gazetted beaches are monitored two to three times per month. The current monitoring frequency for gazetted beaches has been doubled since August 1997 in order to provide more timely beach water quality information to the public. Starting from 1999, sampling on random days including weekends and public holidays has been implemented in order to collect more comprehensive information on beach water quality. During the non-bathing season, all beaches are monitored once a month. The current monitoring frequencies are summarized in Table 2.2.

Table 2.2	Beach monitoring frequencies during the bathing and non-bathing season

Sampling at waist water depth and in-situ measurement of the dissolved oxygen content and temperature of beach water is conducted during each monitoring visit. The weather and beach conditions are recorded. The water samples collected are analysed for E. coli, pH, salinity and turbidity in the laboratory. The beach monitoring protocol is depicted in Figure 2.3.

Figure 2.3	The operational procedures of the Beach Water Quality Monitoring Programme

Sanitary Surveys

In order to enhance the monitoring programme, sanitary surveys of all the beaches had been conducted between 1998 and 1999 to study the catchment characteristics of beaches. In light of the study findings, the location and number of sampling points at each of the beaches had been either confirmed or revised such that more comprehensive beach water quality information could be ascertained and collected. Additional sampling points at the pollution sources or their receiving water in the vicinity of the bathing areas had also been established in order to provide supplementary information for the analysis of the beach water quality data. The revised sampling regime was implemented in 2000.

2.3 Bacteriological Analysis

All beach water samples collected will be analysed for E. coli which is a faecal indicator accepted worldwide for monitoring faecal pollution of bathing water. Prior to 1987, the analysis of E. coli was carried out by the Public Health Laboratory of the then Medical and Health Department. After the establishment of the EPD microbiology laboratory in 1987, the analysis of all beach water samples was carried out by the EPD. At the same time, the analytical method was changed from the Multiple Tube method to the Membrane Filtration method as recommended by the WHO. The Membrane Filtration method was further modified by the EPD to incorporate an in-situ urease test for rapid E. coli analysis. With this modified method, the reporting time for E. coli analysis could be shortened from 4 - 5 days to 3 days.

In 1997, the EPD had further developed and improved the method for E. coli analysis by using a chromogenic medium. This improved method, which does not require the urease test, facilitates the identification of E. coli colonies, and hence the reporting time for E. coli analysis could be further reduced by 50% to 1.5 days. With this improved method for E. coli analysis, more timely beach water quality information could be collected and provided to the public. The EPD will continue to explore more rapid method for E. coli analysis in order to further enhance the beach monitoring programme.