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Subject: Herbicide


From: Mario Galea <mario.p.galea>
Date: Monday, March 15, 2004
I am trying to find a herbicide that can be safely used on our world
heritage sites.

I have tested the product that had been used in the past and found
that it is acidic. The product Monsanto weed killer composed of 41%
isopropylamine of Glyphosphate, in solution, had a pH of 4.5 when
tested. On doing some research on the web I constantly came across
the practice by manufacturers to "acidify" their products in order
to make them more effective. Contacting other possible manufacturers
of herbicide directly proved a futile exercise.

The top preservation/conservation concern are megalithic lime stone
(composition : Calcium Carbonate) and therefore we cannot use acidic
compositions or products which may have dangerous salts which can
find their way into the stone.

In this regard I would be grateful if anyone were to indicate "safe
to use products" preferably with chemical data sheets, or reference
to their composition and effectiveness.

Mario Galea
Senior Conservator
National Museum of Archaeology

                  Conservation DistList Instance 17:59
                  Distributed: Tuesday, March 16, 2004
                       Message Id: cdl-17-59-022
Received on Monday, 15 March, 2004

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