Blue-green algae continue to plague recreation in New Zealand

22 December 2011

In Wellington, the Horizon’s Council is warning swimmers to be careful:

River users should watch for possible growth of blue-green algae. Blue-green algae mats are sometimes found in stony bed rivers after a couple of weeks of low flows. These algae can carry toxins that that are a health hazard to people and animals.

Horizons checked local rivers earlier this month and saw none of these algae, but if there is a long spell of fine weather it might make an unwelcome appearance.

If the river bed is stony, and earthy/musty smelling black mat-like growths cover most of the stones, then go somewhere else.

At least they know enough to realize that toxic algae are not only those you can see floating on the surface!  A similar warning has been issued for the Waipara River (Canterbury) where

Potentially toxic algae has been identified in the Waipara River at the Teviotdale Bridge.

Facts about cyanobacteria:

• Appear 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 to treat every low-flowing river cautiously.

Texas still has some dodgy waters, aka Lake Texoma – but they do have what must be the most comprehensive fishing report available anywhere (the Texoma extract is just one paragraph)!

TEXOMA: Water fairly clear; 48-53 degrees; 4.34′ low. The lake is currently experiencing an outbreak of Blue-Green Algae. Please check www.tpwd.state.tx.us/fishboat/fish/recreational/lakes/texoma prior to planning a trip to Texoma. All contact with water by people and animals is prohibited. Boating is allowed, but boaters are cautioned to reduce their speed because the spray caused by higher speeds can be dangerous if inhaled.

The spray risk warning illustrates just how well informed they are!

In Connecticut, the Hockanum River is about to benefit from less P!

Improvements to the Hockanum River Water Pollution Control Facility will include a new facility to handle solid waste, an odor control system, a new final settling tank, a treatment system to remove phosphorus and other upgrades, according to the report.

In excessive amounts, phosphorus from sewer plants and other sources causes blooms of noxious blue green algae, depleting oxygen and killing fish. The work in Manchester is being driven by government clean water regulations that mandate reductions in phosphorus and nitrogen in treated water.

Plant upgrades willl include a new filtering system, called tertiary treatment, to reduce phosphorus released into the river, Soper said. Work also is to include new electrical equipment, expansion of the existing office building and demolition of existing structures, some of which date to the 1950s.

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