While researching some information a couple of years back in regards to
using pressure-treated timber in the construction of raised-bed vegetable
gardens, a study (I believe done in Arizona) showed that over a period of
years, the chemicals used in the preservative only migrated less than 1/2 an
inch into the soil that was contacting the pressure-treated surfaces.
The bottom-line was that they found the migration/contamination to be of
little significance, as the natural chemical and biological make-up of the
soil would actually breakdown some of the chemicals into harmless compounds.
I would assume that the pressure-treated wood would actually have to
contact the pond water in order to cause a problem, and then, for an
extended period of time. However, frequent water changes _should_ remove
any dangerous compounds.
----- Original Message -----
From: "Scott Davis" <unclescott_at_prodigy.net>
Sent: Friday, March 26, 2004 10:26 AM
Subject: Re: NANFA-- Above ground pond
> A lot of these pressurized timbers are treated with either CCA (chromated
> copper arsenate), followed by ACZA (ammoniacal copper zinc arsenate) and
> (ammoniacal copper quat). All three preservatives are waterborne
> preservatives. These timbers shed their contents very slowly and have been
> applauded for limiting cutting of forest products since they last a lot
> longer than untreated timbers. Some gardeners are cautious about using
> around food producing plants.
> As of January 1, 2004, EPA will not allow CCA products to be used to treat
> wood intended for any residential uses such as play-structures, decks,
> picnic tables, landscaping timbers, residential fencing, patios and
> Should we use them where they might bleed into a pond? I also wonder if we
> should be tossing them into compost piles. :)
> I'm probably at greater risk standing near bus exhaust. Is concern about
> pressure treated timbers unnecessarilly alarmist when considering their
> impact on ponds or streams?
> Thanks and all the best!
> > I have a friend who's grandfather built a swingset using pressure
> > 2x4s. When he got a little old for the swingset, it was broken down and
> > tossed behind the shed, where it eventually became buried in compost,
> > leaves, etc. etc.
> > My friend is now old enough to have grandkids of his own (he doesn't,
> > that's not the point. :) He recently decided that the 50 year old shed
> > to go, to be replaced with a new one. When digging out the soil behind
> > old shed... he found the pressure treated 2x4s, still in usable, good
> > condition.
-- > /"Unless stated otherwise, comments made on this list do not necessarily > / reflect the beliefs or goals of the North American Native Fishes > / Association" > / This is the discussion list of the North American Native Fishes Association > / nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word > / subscribe, unsubscribe, or help in the body (not subject) of an email to > / nanfa-request_at_aquaria.net. For a digest version, send the command to > / nanfa-digest-request_at_aquaria.net instead. > / For more information about NANFA, visit our web page, http://www.nanfa.org /----------------------------------------------------------------------------- /"Unless stated otherwise, comments made on this list do not necessarily / reflect the beliefs or goals of the North American Native Fishes / Association" / This is the discussion list of the North American Native Fishes Association / nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word / subscribe, unsubscribe, or help in the body (not subject) of an email to / nanfa-request_at_aquaria.net. For a digest version, send the command to / nanfa-digest-request_at_aquaria.net instead. / For more information about NANFA, visit our web page, http://www.nanfa.org