[Terrapreta] char & vascular systems

[Mark Ludlow]

Hi Lloyd,

 

Why not test  the char at the test-pot level and see what the uptake in your
test plants is. GC-Mass-Spec determinations typically measures elemental
occurrences; heretical as it may sound, might it not be wise to measure the
effect on the target produce?

 

At some point in the not-so-distant-future these metals will be more evenly
distributed in Earth's productive soils. Well water in some South Asian
countries, used for watering, would help to ensure this, for example. But
soil components-clays, for instance-may in some instances chelate and make
these metals unavailable.

 

One thing seems certain: the occurrence of objectionable metals is unlikely
to trend downward anytime soon.

 

Biochar itself is often associated with polycyclic hydrocarbons, if made
according to standard formulae offered here and elsewhere? Is this stuff
healthy? If so, we should bottle it and sell it to pay for the TP revival!

 

Mark

 

From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Lloyd Helferty
Sent: Thursday, June 12, 2008 10:08 PM
To: 'Philip Small'
Cc: 'terra pretta group'; biochar-ontario at googlegroups.com
Subject: Re: [Terrapreta] char & vascular systems

 

My question to the list was to ask whether the arsenic that the Dynamotive
char might contain could leach out of the char or might stay locked in the
carbon matrix of the char.  My hope was that someone would confirm that the
possibly high Dynamotive char arsenic levels would not make it unsuitable
for organic agriculture.  Although you have not given me any evidence
showing that the levels in the Dynamotive char are in fact safe for use in
soil, I agree that we can still go ahead and try the Dynamotive char anyway
-- for many reasons, not the least of which is that the Dynamotive pilot
plant is located in West Lorne, Ontario, which is only about 160km (~100mi)
from where the first trials might be done.

I'm confident that we will likely be contacting someone at Dynamotive in the
near future and inquire about purchasing of some of their biochar for some
trials here in the province.

 

As an aside, I also noted from the article that tests in Ontario have shown
natural arsenic concentrations as follows: "rural arsenic concentrations
ranged from 0.6 to 30 μg/gm (which I believe translates to 0.6 - 30ppm) with
a mean of 4.0, median of 3.0 and a 90th percentile of 7.6 μg/gm. New urban
arsenic concentrations ranged from 0.6 to 27 μg/gm with a mean of 3.6,
median of 2.9 and a 90th percentile of 6.1 μg/gm. Old urban arsenic
concentrations ranged from 0.4 to 79 μg/gm with a mean of 4.9, median of 3.5
and a 90th percentile of 9.2 μg/gm."

This means the concentrations can be quite a bit higher than the "0.010
milligrams per litre" (10ppm) figure quoted below, although even the 90th
percentile found in the "Old urban" areas is slightly below this level (@
9.2 μg/gm)

 

    Lloyd Helferty

 

  _____  

From: e.philip.small at gmail.com [mailto:e.philip.small at gmail.com] On Behalf
Of Philip Small
Sent: June 9, 2008 2:25 PM
To: Lloyd Helferty
Cc: terra pretta group
Subject: Re: [Terrapreta] char & vascular systems

 

On Sun, Jun 8, 2008 at 7:39 PM, Lloyd Helferty <lhelferty at sympatico.ca>
wrote: 


I've looked up Health Canada's guidelines for Canadian Drinking Water
Quality, and they have established levels of Arsenic at 0.010 milligrams per
litre (kg), based on lifetime exposure to arsenic from drinking water, which
is 1000X more stringent than the Dynamotive char, so I'm not certain that
the water flowing through this biochar would be drinkable nor whether any
veggies that might grow in the medium could be certified organic.

We should all be concerned about arsenic
<http://www.aehs.com/conferences/international/glance/tuesday/arsenic.htm>
in soil because it is a carcinogen even at the natural background levels at
which arsenic occurs. The regulatory cleanup standard for arsenic
contaminated soil can calculate to between 0.1 and 0.5 ppm (varies with the
regional calculation).  Yet it is very likely that everyone reading this
lives in an area with natural soil arsenic levels above this standard. That
doesn't mean that the veggies grown in your garden soil can't meet organic
standards.  That doesn't mean the groundwater percolating through your
garden soil will fail Canada's arsenic standard for drinking water.  

I consider natural soil arsenic to be the most impossibly problematic
"contaminant" that environmental regulators are required to make sense of.
The Dynamotive charcoal arsenic levels look natural to me.  I respectfully
suggest we cut Dynamotive char some slack on the arsenic.

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