MNLY: The Manly Blog, Sydney Sustainability: Drinking Water & Healthy Water Bodies Pt II

Sydney's drinking water,we are being told 'is no public health risk'.
"A, there is nothing we can do about it;
B, it's a perfectly natural phenomenon which is a response of lots of nutrients being washed into the water;
C, it's not toxic”.
The 'non toxic' growth of blue-green algae expanded over the weekend from 14 to 26 km (image) in Warragamba Dam. Daily 'water quality results' do not show up any 'blooming'.
While industry and government representatives are being instructed on 'water quality management and health risk reduction' the public is ensured that Microcystis aeruginosa (pdf) species is only 'potentially harmful', but you ”may notice a change in taste and odour.”

Australia's Water Quality and Treatment states the following in its 'Blue Green Algae Guide (pdf)

“Blue-green algae produce three main types of toxin:

• Endotoxins are thought to produce allergic reactions, skin rashes, irritation of the eyes, and gastroenteritis.
• Neurotoxins damage nerves and can cause muscle tremors, especially in the muscles animals and people need to breath.
• Hepatotoxins damage the liver. They may also increase the risk of certain types of cancer.

To put the toxicity of blue-green algae in perspective, Microcystis, one of the blue-green algae found in Australian waters, produces a toxin called microcystinLR. Microcystin LR is 200 times more toxic than cyanide.

Blue-green algal toxins are colourless, odourless,and can remain present in the water weeks after the blue-green algae have disappeared. They are not destroyed by boiling affected water.”

A town water supply was closed down due to cyanobacteria (HABs) some time ago in NSW. WHO recommends that " levels of 10 cells mLˉ" of cyanobacteria should not get in contact with humans. “The major route of human exposure to cyanobacterial toxins is the consumption of drinking water” (WHO, pdf) Unfortunately we are not told the levels of Sydney's bloom in the drinking water or the ocean.

In some places “the highly toxic algae Microcystis aeruginosa” threatens human health. “Health experts warn that even modest exposure to the toxin produced by the algae, called microcystin, can lead to skin rashes, vomiting, and diarrhea.” Various stakeholders believe that “ the regional water board not only has the authority but the mandate to protect the public from toxins like these in water bodies.”

Once HABs are present in the 'red surf' of the ocean, the sea breeze blows toxic aerosol over the coastal residents. “During the red tide, admissions for pneumonia, bronchitis, asthma, sinus infections and similar afflictions rose 54%.” Surf club's sign read: "Some Red Tide = Coughs. Sneezes. Dead Fishes." People wear masks.

“A scientific consensus is emerging that commercial agriculture and coastal development, in particular, promote the spread of harmful algae. They generate runoff rich in nitrogen, phosphorous and other nutrients that sustain these microscopic aquatic plants. In essence, researchers say, modern society is force-feeding the oceans with the basic ingredients of Miracle-Gro.”
“Industrial society is overdosing the oceans with basic nutrients - the nitrogen, carbon, iron and phosphorous compounds that curl out of smokestacks and tailpipes, wash into the sea from fertilized lawns and cropland, seep out of septic tanks and gush from sewer pipes.”