16 June 2011

Photo: Bill Harding

What’s polluting our lakes” is the heading of a news article from Upper Deerfield Township in the US.  A singularly-important question from which, typically, follows an analysis of all potential contributing sources in the catchment.  A couple of years ago I co-authored a protocol for doing just this, a document that includes simple modelling tools for assessing nutrient loads and by how much they should be reduced to meet water quality targets.

Some readers ask why a lot of the info in this blog is currently from the US? This is because while we in South Africa are deep into winter, as are Australia and New Zealand, the northern hemisphere countries are getting ready for their summer break and algal issues are important to them.  This is not to say that algal blooms don’t occur in winter, its more about that there is less recreational demand to draw attention to them.

While on the topic of catchment assessments, Ohio is looking to target overuse and over-supply of phosphorus on agricultural lands.  From Peterborough County (Canada), Galway-Cavendish and Harvey Township residents who draw water from the back channel section of the northeast area of Pigeon Lake have been advised to find an alternate source of water after algae was found in the lake, the Peterborough County-City Health Unit announced Wednesday night.

On the topic of recreation, England’s Big Swim, The Great North Swim at Lake Windermere (England’s largest lake), is going ahead this year.  Readers of this blog will recall how this had to be cancelled last year due to a blue-green algal bloom.

Back to phosphorus in detergents (see yesterdays blogs).  The European Union is getting set to expand its bans on laundry detergents that contain phosphorus and to widen this to include dishwasher soaps.  Under the proposal, the European Commission would also have to decide by 2016 whether to extend the ban to industrial and institutional use of detergents and whether to further cut phosphate levels in soap for dishwashers and washing machines.

Leave a Reply

Your email address will not be published. Required fields are marked *