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  • From: Elfpermacl@aol.com
  • To: permaculture@listserv.oit.unc.edu
  • Subject: Re: ferro-cement cisterns
  • Date: Sun, 27 Sep 1998 13:10:58 EDT


In a message dated 9/26/98 11:34:17 PM, you wrote:

<<I did test our water last year with an inexpensive garden kit, and the
water was right at neutral on the pH scale. We don't have horrible acid
rain here (yet), so it may not be as acidic as other parts of the country.
We also don't add any chemicals, salt, or anything to the water. It's
certainly more neutral than any of the well water around here, which is
nasty stuff that has to be treated before drinking. Apparently in the
Caribbean, where there is no drinking water, rainwater collection systems
are used quite frequently.
>>

Actually if your rainwater is neutral, you have an alkaline source of
pollution. Unpolluted rainwater is pH 5.5, mainly due to dissolved carbon
dioxide plus a few other highly soluble acid-forming gases that are always in
air (e.g, S02), though these are less common. To become pH 7, some alkaline
substance must be in the atmosphere, roof, or tank to make the difference.
Neutral rain is as abnormal as acid rain (pH 4.5 for example), and carries the
same contamination concerns.

The pH of rain from unpolluted air varies over geological epochs--5.5 is a
current figure representing the current low concentrations of co2 in the
atmosphere (current here meaning in this interglacial period). Rising CO2
above the normal is part of the cause of increasing acidity (lower pH) of
rain.

We may take it as given that all rain everywhere is now polluted. You can see
this when you fly--a scummy grey or sometimes yellow-grey film covers the
ground level, particularly around cities. You can feel the aircraft vibrate
as it enters this film on landing. I've seen it in New Zealand and I've seen
acid rain damage there and in Ireland where large bodies of water with minimal
sources of pollution allow for cleansing (through deposition and rain) and
mixing of air to be as clean as it gets on planet Earth.

Unless you distill water or use reverse osmosis, two very energy-intensive
activities with residue to be disposed in some way, your water is polluted.
Some places aren't as bad as others, obviously, and if you are using pH to
test, then 5.5 has a chance of being fairly clean (or pollted by chemicals
that neutralise each others effects which must happen sometimes). \

For Mother Earth, Dan Hemenway, Yankee Permaculture Publications (since 1982),
Elfin Permaculture workshops, lectures, Permaculture Design Courses,
consulting and permaculture designs (since 1981), and annual correspondence
courses via email. Copyright, 1998, Dan & Cynthia Hemenway, P.O. Box 52,
Sparr FL 32192 USA Internships. YankeePerm@aol.com

We don't have time to rush.

A list by topic of all Yankee Permaculture titles may be found at
http://csf.colorado.edu/perma/ypc_catalog.html
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