[Terrapreta] char & vascular systems

[Mark Ludlow]

Hi Richard,

 

I have encountered bioremediation schemes for removing PAHs from contaminated soils, with PAH-utilizing bacteria. But the PAHs are toxic to other microbes and many are established carcinogens. Perhaps there are microbes that utilize PAHs as well as provide some positive secondary benefit to the soil. If so, I'd like to learn about them. Biochar lore suggests that good biochar has PAHs (condensed?) within its structure. The role of these organics in the total scheme of things is confusing to me. Is creosote, for example, good for living things?

 

Mark

 

From: Richard Haard [mailto:richrd at nas.com] 
Sent: Friday, June 13, 2008 2:40 AM
To: mark at ludlow.com
Cc: 'Lloyd Helferty'; 'Philip Small'; 'terra pretta group'; biochar-ontario at googlegroups.com
Subject: Re: [Terrapreta] char & vascular systems

 

My current soil tests do not look at arsenic but Mark has a good suggestion. Do plants take up this element is a basic question. As a baseline look at arsenic typical in dried brown (Phaeophyta) seaweed, kelp (Nereocystis, Macrocystis). This is a material commonly used in organic agriculture and as food supplement. I've been told to be careful consuming dried kelp but is it taken up by plants? Also what is arsenic content of 'green sand', and rock dust from olivine and granite relative to this biochar? These are also used as soil supplements in organic agriculture.

 

For my household water we maintain baseline studies with mass spectrometer every 5 years. A spectrum analysis is about $120 in Vancouver, BC. If a pot test is done I would think about conditions where arsenic is released or flushed from any chelation properties in soil, ie mass replacement. Not sure about the chemistry here but would potassium or sodium flush off the arsenic?

 

Mark - those organic, molocules associated with charcoal is biologically liable and may be valuable substrate for beneficial microbes. Not so with arsenic once you got it it is there. Think about the era where arsenic was once used as pesticide in apple orchards of eastern Washington, some of these soils are harboring high levels of this mineral. There must be a body of research on uptake

 

Rich

On Jun 12, 2008, at 11:29 PM, Mark Ludlow wrote:





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 90thpercentile 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 90thpercentile 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 90thpercentile 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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