06 Sep, 2017

Blue-green algae causing taste and odour issues in American drinking water lake

It is widely documented that blue-green algae can produce toxins that affect the taste and odour of drinking water. As the northern hemisphere is at end of their summer, many lakes that have been dominated by algal blooms are experiencing algal death and degradation. This process has lead to high concentrations of algal cell compounds being released into the water column. These compounds, including 2-methylisoborneol (MIB), are causing taste and odour issues.

A recently published article focuses on the taste and odour issues being experienced in a drinking water lake called Beaver Lake in Arkansas, USA. The article by the Beaver Water District (BWD) can be found at http://www.bwdh2o.org/2017/09/algae-is-the-culprit-behind-drinking-water-taste-and-odor-issues/.

The article states that James McCarty, Manager of Environmental Quality for BWD, has assured stakeholders that the BWD is monitoring the water quality and the water is currently safe to drink. The article goes on to say that the MIB concentration currently in Beaver Lake is not at a level that would be harmful to humans. However elsewhere on their website they acknowledge that some species of blue-green algae can be responsible for releasing other compounds that may be toxic to humans and animals.

Regular monitoring of MIB, as well as other potentially toxic compounds, can be very expensive. In many instances around the world, the concentration of MIB in lakes has caused: the closure of drinking water facilities; or the use of expensive water treatment products in the associated water treatment plants prior to the release of water to the general public.

It is well known that algal blooms occur in water containing high concentrations of nutrients such as phosphate. The article states that the nutrients in the water column in Beaver Lake are being released from the sediment zone during early autumn when the lake has its turnover period. In the summer months, the warm climate and the supply of nutrients in the water column fuels the proliferation of algal blooms.

Phoslock should be used to bind easily releasable phosphorus stored in sediment prior to the turnover period of a lake. This would ensure that the concentration of phosphorus in the water column is kept to a minimum and algal bloom formation would be stemmed. This in turn would solve the taste and odour issues in the drinking water before it becomes a problem.