SCDHB

Community and Public Health has lifted its algal bloom health warning, issued for the Opihi and Pareora rivers.

Recent river bed surveys at Saleyards Bridge, SH1 Bridge and Waipopo on the Opihi River; and also at the Pareora Huts river area has shown the quantity of potentially toxic blue-green algae (benthic cyanobacteria) in these rivers has decreased to below levels that are of a concern to public health.

Canterbury Medical Officer of Health Dr Alistair Humphrey says Environment Canterbury's sampling of the Opihi and Pareora rivers has now finished for this season and will resume again later in 2011. Appropriate information signage will be left in place.

Facts about cyanobacteria:

• Appears as dark brown/black mats attached to rocks along the riverbed.
• The algae occur naturally but can increase rapidly during warmer months.
• It often has a strong musty smell and algal toxin concentrations can vary over short periods with changing environmental conditions.
• Although high river levels will remove the algal bloom, detached mats can accumulate along the shore and increase the risk of exposure to toxins.
• If a health warning is in place avoid contact with the water.
• Although district or city councils may place warning signs, these may not be seen at the numerous river access points, hence the need for people/ dog-walkers to treat every low-flowing river cautiously.

For further information click here 

Contact Community and Public Health on (03) 687 2600.