Introduction

In the past, guidelines for assessing the public health risk of using recreational waters have been largely based on microbiological faecal indicator counts. The previous (1999) marine bathing guidelines (Recreational Water Quality Guidelines) were developed using the results of international and New Zealand studies, and after consultation with regional and local environmental and health agencies.

The guidelines presented here move away from the sole use of guideline values of faecal indicator bacteria, and instead use a combination of a qualitative risk grading of the catchment, supported by the direct measurement of appropriate faecal indicators to assess the suitability of a site for recreation. In addition, alert and action guideline levels are used for surveillance throughout the bathing season.

The two components to providing a grading for an individual beach are:

• the Sanitary Inspection Category (SIC), which generates a measure of the susceptibility of a water body to faecal contamination
• historical microbiological results, which generate a Microbiological Assessment Category (MAC), which provides a measurement of the actual water quality over time.

These two combined give an overall Suitability for Recreation Grade (SFRG), which describes the general condition of a site at any given time, based on both risk and indicator bacteria counts. This grade helps to determine whether ongoing monitoring is required, and provides the basis for telling people whether or not the water is suitable for recreational use, from a public health perspective.

Throughout this document the term ‘beach’ refers to both marine and freshwater recreational water sites.

The aim of these guidelines is to help water managers control the public health risk from microbiological contamination in recreational waters, and to provide for monitoring and reporting on the general health of beaches. The guidelines were designed to provide guidance to water managers in implementing the Resource Management Act 1991 (RMA), and the Health Act 1956 for shellfish – gathering or contact recreation. A crucial part of this is ensuring that the public are informed of the health risks in time for them to make informed decisions about whether to enter the water. The guidelines replace the previous Ministry for the Environment / Ministry of Health Recreational Water Quality Guidelines published in November 1999.

Guidance is provided for three categories of water use:

• marine bathing and other contact recreation activities
• freshwater bathing and other contact recreation activities
• recreational shellfish gathering in marine waters (but not commercial shellfish harvesting).

The Ministry for the Environment is specifically concerned with ensuring that the public has ready access to regional or local authority water quality information on the potential health risks from faecal contamination of recreational waters. The guidelines should provide this.

The guidelines also provide the monitoring protocol for the state of the environment indicators “the percentage of monitored beaches in each beach grade”, and “the percentage of the season beaches or coastal areas were suitable for contact recreation or shellfish gathering”.

The guidelines have been developed over an extensive period of consultation with regional and local councils and health authorities, and present a preferred approach to monitoring recreational waters. They are not legislated standards that must be adhered to at all times.

The guidelines cover the monitoring and interpretation of results from surveys for bacteriological indicators of faecal contamination in recreational waters. They do not cover other impacts on the above water uses, such as water clarity, chemical pollution, or marine biotoxins from algal blooms. The guidelines should not be used as the basis for establishing conditions for discharge consents, although they may be used as a component for decision making.

Documents that may be of interest to anyone managing water for contact recreation include two produced by the Ministry for the Environment:

• Water Quality Guidelines No 1, which covers the management of biological growths in rivers used for swimming
• Water Quality Guidelines No 2, which covers the management of water clarity for bathing in freshwaters.

These guidelines take precedence over the ANZECC Water Quality Guidelines for Fresh and Marine Water for microbiological water quality.

Finally, visit the Ministry for the Environment’s website for further information on water-quality publications.

These guidelines constitute the monitoring protocol for recreational beaches in New Zealand. Although the focus of this document is on monitoring recreational waters for public health purposes, regional councils and the Ministry for the Environment also use this information to report on the state of the environment at a regional and national level.

Indicators for recreational waters have been developed through the Ministry’s Environmental Performance Indicators (EPI) Programme, and will be reported nationally through the EPI website.

These guidelines and the accompanying explanatory notes provide information on the data management relationship between the Ministry and data providers, and contain guidance on data transfer protocols. Links with other indicators are also discussed.

See Note G(iii) for discussion on the EPI programme.

See Note G(v) for discussion on integrating state of the environment and public health programmes.

Conditions on the use of these guidelines

These guidelines have been prepared to support the management of bacteriological water quality for recreational use. These guidelines cannot be applied to water uses other than recreational use.

Guidance for wastewater discharges

These guidelines cannot be directly used to determine water quality criteria for wastewater discharges because there is the potential for the relationship between indicators and pathogens to be altered by the treatment process. The relationship between indicator bacteria and disease-causing bacteria, viruses and protozoa in the discharge needs to be established.

The Ministry for the Environment has published the Wastewater Monitoring Guidelines, which provide guidance on monitoring treated wastewater. Information on these guidelines is available on the Ministry’s website. Information on the Sustainable Wastewater Management Handbook for Smaller Communities is also available on the Ministry’s website.

Applying the guidelines to water impacted by wastewater discharges

These guidelines should not be directly applied to assess the microbiological quality of water that is impacted by a nearby point source discharge of treated effluent without first confirming that they are appropriate. This is particularly important for disinfected effluent (Disinfection Review Group 2002) and for waste stabilisation pond effluent (Sinton et al 2002). It is important when planning the location and degree of treatment for wastewater treatment plants to recognise that the guideline values are not necessarily a guarantee of safety.

While it is correct to infer that water exceeding the guideline values poses an unacceptable health risk, the converse is not necessarily true. This is because effluent may be treated to a level where the indicator bacteria concentrations are very low, but pathogens such as viruses and protozoa may still be present at substantial concentrations, effectively changing the indicator/pathogen ratio.

To assess the microbiological quality of water that is impacted by a discharge of treated effluent, the relationship between indicator bacteria and key pathogens (such as viruses and protozoa) must be established for that treatment.

This would require the generation of statistically robust data to establish that the treatment process produces an effluent that meets the guideline indicator bacteria values, and is capable of destroying pathogenic micro-organisms.

Treatment plants also require ongoing auditing and monitoring. Wastewater plants may not operate 100% of the time (e.g. during high water flows) and the health status of the population at any given time affects the pathogens likely in wastewater.