Natural swimming ponds

[Théière]

For anyone contemplating a natural swimming pond because they don't like chlorine even at 1 part per million in water.

Andy Holmes the Olympic rower died from weil's disease, it just takes one infected rat to take a swim in your pond............

http://www.independent.co.uk/news/people/news/rower-who-won-gold-with-redgrave-dies-of-weils-disease-2116456.html

Information on chlorine and leptospira

[Araucaria]

I notice on that scary leptospirosis website that the bacteria is also killed by salt water: it doesn't say how many ppm though.

[Théière]

A good point Araucaria, from the text on the site they seem to indicate they mean sea water which is in the region of 35000 ppm a fair bit higher than a salt water pool at 2000-6000ppm.

http://www.leptospirosis.org/topic.php?t=11

[pachapapa]

And ragondins have bigger bladders.

[chem geek]

Since this bacteria is able to survive in the blood and kidneys and since blood serum has 0.8 to 1.1 ppm copper ions (see [url=http://www.globalrph.com/labs_c.htm]this link[/url] and [url=http://www.bloodbook.com/ranges.html]this link[/url]), the use of copper ions alone in a swimming pool will not kill this bacteria.  Chlorine apparently will, though I can't find specific kill times.

As for salt level, blood serum has 95 - 106 mmol/L which at 58.443 g/mole sodium chloride is around 5800 ppm salt (human tears, by contrast, are closer to 9000 ppm salt).  So the statement about salt killing this bacteria must be about much higher salt levels such as in the ocean (as was mentioned by Théière).