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[APD] Re: Ironite
In what FORM is the arsenic present in ironite, i.e. which arsenic
compounds are present? This would make a big difference in the toxicity
of that arsenic.
> OK; I know it's off topic but...
> I too, am VERY skeptical of this sort of thing. So,
> as I was interested, I looked further than the ironite
> lawsuit press release. By looking at the Washington
> State fertilizer ingredient webpage (given on the
> press release) I found that Ironite contains 4380 ppm
> arsenic. So, I did some quick and dirty math. Let's
> assume that I broadcase Ironite in my garden at the
> recommended rate (5 lbs per 1000 square feet), and
> that it is mixed into the top 3 inches of soil (let's
> assume I am mainly using it as a top dressing and not
> mixing deeper than 3"). Therfore, I would be
> increasing this soils arsenic concentration by 0.94
> ppm. Let's assume I do this every spring for 21 years
> (not unheard of). I have then increased the arsenic
> concentration in my soil by 19.87 ppm. Note that the
> EPA Superfund cleanup level for arsenic is 20 ppm. In
> addition, soils contain background arsenic levels to
> beging with, so my real time to reach this
> concentration would be shorter than 20 years.
> Ironite's website claims that vegetables grown on soil
> treated with Ironite do not contain increased levels
> of arsenic due to the type of arsenic in Ironite.
> However, from a health standpoint, that's not the
> issue. Most plants do not take up inorganic arsenic.
> The problem arises from direct contact with arsenic in
> the soil, ingestion of the soil particles (e.g. on
> veggies), and inhalation of the soil dust. Children
> are especially at risk; it is estimated that children
> ingest about 200 mg/day of soil (100 mg/day for
> So, learning this, I'm uncomfortable with the
> following potential scenario: I buy a house from an
> 80-year old retiree, who has gardened in the same spot
> for 30 years. I remove the garden and plant grass.
> Should I let my child play there?
> Risk assessors have formulas to calculate risk based
> on the amount of arsenic in the soil and the age of
> the person there, as well as how often they are there
> and other factors. I don't know how to do this, but I
> would not knowingly bring my child to a playground
> with 20 ppm arsenic in the soil. Never mind having it
> in my back yard.
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