Archived posting to the Leica Users Group, 2001/01/31

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Subject: Re: [Leica] Water Chemistry for Dummies
From: Hans-Peter.Lammerich@t-online.de
Date: Wed, 31 Jan 2001 21:34:14 +0100
References: <200101310801.AAA04557@mejac.palo-alto.ca.us>

Tap water is monitored better than bottled water. From the hygienic
point of view, bottled water with gas is safer. The acid environment is
bacteriocid. Brita filters make water "softer" (ion exchange), but not
healthier. There is even a risk that bacteria grow in wet filters!

Chlorination is necessary, but dosage can be fine-tuned (at the
treatment plant or reservoir) in a way that there is no residual smell
or taste for the end user. Moreover, chlorine is more hazardous to pipes
and pumps than to the human body. So it is wise to use it moderately. I
however find that third world countries prefer generous chlorination, if
they can afford to buy chlorine on regular basis. This is safer for
systems with leaks (drawing in air and dirt) or frequent power failures
(increasing the average time from treatment plant to end user).

Fluoride (like chlorine) is a poison. At least here in Europe it is
therefore not recommended to add fluoride to the tap water for caries
prophylaxis. Better go for individual dosage with toothpaste.

The Dutch abstract drinking water from the river Rhine which is the
toilet of Central Europe. Many German cities upstream use deep wells
right besides the river which are not much better. The process
technology for treating potable water is approaching the process
technology for treating sewage. Expensive, but doable and safe. I
however recall an incident at the Hoffmann-Laroche chemical plant in
Switzerland, more than ten years. The breweries in Dusseldorf and
Cologne closed down for a week or so. They use tap water.

Hans-Peter