Monthly Archives: December 2011

Testing the Lead Testers

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Gardening, Lead, Soil
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Varian ICP-MS from Wikipedia

Dear readers,

Excuses for a technical post here, but we need your scientific expertise. If you have experience in soil laboratory testing techniques, or know someone who does, please send us an email at [email protected] or leave a comment. We’re attempting to reconcile slightly different lead results from three different labs and I’d like to be able to write about soil testing methods. Two of the labs we sent samples off to (UMass and Timberleaf Soil Testing) use inductively coupled plasma mass spectrometry (ICP) to test for lead. Wallace labs uses an extractant, AB-DTPA (ammonium bicarbonate Diethylene Triamine Pentaacetic acid).

Here’s how Wallace described their lead testing techinique,

We use AB-DTPA (ammonium bicarbonate Diethylene Triamine Pentaacetic acid).

It is a gentle extractant and it mimics roots in extracting minerals from the soil. Most often environmental tests are made with boiling acids which are more aggressive than roots. The AB-DTPA method is a standard testing method of the Soil Science Society of America. It is called the universal extractant. It measures the bioavailable or plant available minerals which is expected to be adsorbed by plants. Most of the background heavy metals are occluded and are unavailable to plants. Our testing does not see the occluded metals.

Total lead is approximately 10 times higher than our AB-DTPA measured lead. We recommend that AB-DTPA lead be less than 30 parts per million for home production of edible produce.

UMass says,

We use a modified Morgan solution (dilute glacial acetic acid and ammonium hydroxide) to measure extractable lead (using ICP).  Total Estimated Lead is calculated using a correlation established during a study performed here at UMass that compared total digestion levels to extractable levels using 300-400 soils.

I divided one soil sample into three parts and sent a portion to three labs. While all three labs indicated the presence of above natural levels of lead, there were enough differences between the tests to warrant a closer look at the techniques. Your assistance would be greatly appreciated and we’ll share what we find out.

Food Preservation Resources

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Food, Food Preservation
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Due to a popular post on making prickly pear jelly, we get a lot of emails asking for advice on canning. So I thought I’d list three favorite food preservation resources.

I like to go to respected sources when canning for reasons of both safety and reliability. While botulism is fairly rare, it’s a highly unpleasant way to pass this vale of tears. But beyond the safety issue, if I’m going to go through the work of canning, I want to know that the recipe is going to work. There are few things more frustrating than a big batch of jam or jelly that doesn’t set. Yes, you can call it “syrup” but it’s still a big blow to the ego. 

My three favorite resources are the National Center for Home Food Preservation which has recipes for all kinds of food from fruit to meat, the Ball Complete Book of Home Preserving and Ball’s website. All of the recipes in these two websites and book follow USDA guidelines.

The reason I came up with a prickly pear recipe is that I couldn’t find any other ones that worked. But if I were canning something like, say, peaches I’d go with one of the above authorities. If you have a favorite food preservation resource leave a comment.

Cat allergies, cat hearts, cat cuteness: an update on all things cats.

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Animals, Cats, Domesticus
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Many apologies to people who don’t come here to hear about the cats.
This won’t take long.

I just wanted to give two quick updates. The first is to let you all know that Phoebe is doing amazingly well despite having an insanely malformed heart. The meds have perked her up, so she and Trout are playing all the time. To look at her you’d never think anything was wrong. So thank you so much for all  your supportive thoughts and let’s hope she stays with us a good while.

The second update is on allergies. I’ve posted about this before. When we got Phoebe I was technically allergic to cats, but I decided to push on through that little impediment, powered by the twin engines of Denial and Will, just as I’d done when we got our dog. It worked.

Then Trout came into our lives. I hoped that I’d get a pass on the allergies, as I’d already adjusted to Phoebe. But instead I had to start all over fresh with him. And it was worse this time around. Not least because Trout is super affectionate and is always, quite literally, in my face. (He kisses!)

I worried that I might have overloaded my system beyond all tolerance, but guess what? The symptoms have been gone for almost a month now, long enough for me to declare victory over pet allergies–my third victory so far.

The secret? Pig-headedness. Willingness to be constantly snotty. Absolute faith in mind over matter. I took nothing for relief, nothing at all. Not even nettle tea this time, because I was out of nettles. I think it’s important not to have a crutch, to force your body to work through it. The whole process took about three months.

I realize that there are people with worse allergies than mine, and I don’t mean to underplay anybody else’s experiences. I’m sure some allergies are so severe that they can’t be ignored. But I’m intrigued that this works, for me as well as for others I’ve heard from, and just wanted to say that it is possible to break free.