Protecting the quality of local recreational water
Community and Public Health is involved with the quality of coastal waters and freshwater waterways which are used for a range of recreational activities such as swimming, sailing, boating, surfing, water skiing, underwater diving and shellfish gathering.
The quality of recreational water is an important environmental health and resource management issue.
Health Risks Associated with Contaminated Water
Water can be contaminated by human or animal excreta (poo) containing disease causing micro-organisms such as viruses, bacteria and protozoa.
Contamination poses a health hazard when the water is used for recreational activities such as swimming and other high contact water sports.
There is a risk that water will be swallowed, inhaled or come into contact with ears, nasal passages, mucous membranes or cuts in the skin, allowing pathogens or algal toxins to enter the body.
The symptoms of exposure to contaminated water are usually minor and short lived, however there is the potential for more serious diseases including hepatitis A, giardiasis and cryptosporidiosis.
Health Risks associated with Algal Blooms
Algal blooms are appearing more frequently in our waterways. Algal blooms in lakes can be blue/green in colour floating on the surface or colourless globules suspended in the water.
Algal blooms are also found in rivers as blackish benthic mat-forming cyanobacteria clinging to rocks or collecting at the riverbank. Some cyanobacteria species produce toxins.
Symptoms of exposure to toxic algae can range from allergic reactions, asthma, eye irritations, and rashes to rapid onset of nausea and diarrhoea to gastroenteritis to other specific effects such as liver damage and possibly developing cancers.
Health Risks associated with Mahinga kai
Water containing micro-organisms, chemicals, phytoplankton or cyanobacteria can pose a risk to health through recreational contact, drinking and gathering mahinga kai.
Mahinga kai species associated with water are fish (including tuna and inanga), kanakana shellfish (such as mussels, oysters, scallops, tuangi and tuatua) as well as seaweed and watercress.
- Find out about the public health risks around mahinga kai gathered from water – updated November 2019 [210KB PDF].
Responsibility for Monitoring Water Quality
Responsibility for Monitoring Water QualityRegional councils like Environment Canterbury coordinate the monitoring of the various sites throughout our region and inform Community and Public Health and the territorial local authority (TLA) if contamination levels present a potential health risk.
The Territorial Local Authority places warning signs to inform the public where a health risk is identified, and takes steps to remove the contamination if possible.
Community and Public Health supports the TLAs in advising the public of the risk and ensuring that they deal with the contamination appropriately.
- Find out the latest on recreational water quality in Canterbury (Environment Canterbury).
- Find out the latest on recreational water quality on the West Coast (West Coast Regional Council).
- Read about the experience of Canterbury students doing summer water monitoring (Environment Canterbury).
Documents
- LAWA River Water Quality National Picture Summary 2021.
- 2019 Christchurch Surface Water Quality Report (Christchurch City Council 2020).
- National Policy Statement for Freshwater Management (Ministry for the Environment 2020).
- Impacts of climate and freshwater policies: Literature review (Ministry for the Environment 2020).
- Our freshwater 2020 (Ministry for the Environment).
- Assessment of anatoxin levels in the water of rivers affected by Phormidium blooms (Ministry for the Environment 2020).
- Review of the New Zealand Guidelines for Cyanobacteria in Recreational Fresh Waters (Ministry for the Environment 2009).
- Microbiological Water Quality Guidelines for Marine and Freshwater Recreational Areas (Ministry for the Environment 2003).
Downloads
Download or order resources from the Community Health Information Centre.
- Recreational Water Quality: What you need to know.
- Cryptosporidium and Giardia.
- Public Health and mahinga kai gathered from water.
Links
Contact your local CPH office for further information:
CANTERBURY
Ph: +64 3 364 1777
Fax: +64 3 379 6125
SOUTH CANTERBURY
Ph: +64 3 687 2600
Fax: +64 3 688 6091
WEST COAST
Ph: +64 3 768 1160
Fax: +64 3 768 1169
For additional information or to report water pollution, contact:
Environment Canterbury Pollution Hotline
Ph: 03 3664 663 or
0800 765 588
West Coast Pollution Hotline
Ph: 0508 800 118
Warnings to avoid some local waterways
Updated: 19th October 2021
Recreational water users are reminded to avoid contact with some Canterbury waterways. Recently added warnings are highlighted in bold.
Potentially toxic algae or cyanobacteria or a high level of faecal (poo) bacteria is currently present in the following locations in the region:
- Lake Forsyth/ Te Roto o Wairewa
- Lake Rotorua (Kaikoura) – this is a permanent warning.
Find out more about the public health risks of toxic algal blooms [161KB PDF].
Find out more about keeping dogs safe from toxic algae (Environment Canterbury).
Visit the Environment Canterbury website for more information on water health warnings. Routine monitoring of waterways for summer runs from October to March each year.
