Red wrote:
On Sun, 03 Aug 2003 09:13:56 +1000, Terry Collins wrote:
Apparently not the case. There have been posts for a few years from the
USA that this stuff leaches the chemicals all the times. I vaguely
remember some enquiry in Australia into these claims being announced recently.
Quote from this CSIRO document here, Read the crops & mulch part
http://www.ffp.csiro.au/wft/wpc/ccafact1.html
Did you actually read it? And your point is?
Unfortunately the CSIRO is no longer a totally ethical concern. Its main
ethic now is getting money out of industry to survive. It did notice
that it didn't actually examine the break down products either.
Leaching
Nearly all the CCA fixed within timber remains there over its lifetime of
service; if it did not, the wood would rot and fail in much less than the 30-50
year period for which it is often guaranteed.
But how is CCA wood actually removed from the environment? It isn't. At
best, it just engs up in land fill slowly raising the background levels
of toxic chemicals.
However, a small amount of
leaching inevitably occurs. This can show up in small rises in arsenic levels in
the soil close to posts and poles; studies have found levels return to normal
within about 100 mm of posts and 100-200 mm of poles. Simple precautions, such
as those described below, can be taken to minimise any perceived risks from the
leaching.
So kids playing on it do ingest the chemicals on the surface! Which is
what some group in the USA is on about at the moment.
Crops
A number of studies have shown that CCA is not absorbed into above-ground food
crops such as grapes, tomatoes and cucumber. There are, however, some reports of
a slight increase in arsenic content in root crops such as carrots and beets
grown against treated timber, although the arsenic is in a safe organic form and
most of it is removed with peeling.
This seems contradictory to me. It says the vegetables are absorbing CCA
from the soil, then you remove the skin, which is generally accepted as
the best vitamin and mineral source. Sort of like having TOFU bugers
instead of red meat burgers.
I must admit, it never made good sense to me the bring any wood laden
with toxic chemicals onto my property in the first place. I'll continue
to be skeptical of any such claims about "perfectly safe".
--
Terry Collins {:-)}}} email: terryc at woa.com.au www:
http://www.woa.com.au
Wombat Outdoor Adventures Bicycles, Computers, GIS, Printing,
Publishing
"People without trees are like fish without clean water"