This is some very serious S#!%. I just talk to a Berkey Water filter Rep and this is what she told me:
Nicole 15:49
At this time, we haven’t have data for Microcystin. It is a toxin produced by the bacteria. So even though the Black Berkey Elements can remove 99.9999% of bacteria, we cannot be certain it will remove this toxin. Therefore, we cannot recommend using the Berkey Elements to filter water contaminated with Microcystin.
If a Berkey Water Filter can’t make it fit to drink I wonder how it ever will every be fit to drink! Berkeys are used to make good drinkable water by many people working in third world hell holes were passable water is what we would call sludge. Looks to me that the excrement has collided with the rotating air circulator!
According to the EPA link it looks as if ozone treatment is the most effect. Chlorine and (wood, not bamboo) charcoal can be done, but with a little more difficulty. This is at the individual level. I don’t know how they could treat at the water company lake intake point.
Also this is an example of why having a well or spring is better than depending on water sourced from a lake or pond.