September 16, 2009

No, that’s not a directive to Mayor Dellums (though if he’d like to take it as one, I have no issue with that!) It’s that other kind of lead.

After a great tip from a reader (thanks, Len!) I recently called up the Alameda County Lead Poisoning Prevention Program (ACLPPP) to see what they could tell me about lead testing and lead safety, especially in soil. First, I have to say—these guys are rock stars! They called back promptly and had all sorts of information to share. A couple of days later, I received a complete lead test kit in the mail, with detailed instructions on how to test my soil, paint, and dust.

I picked out nine areas—five sections of the backyard, two painted areas, and two dusty windowsills—and sent off the samples to be tested. (For FREE!) Just a few days later, along came the results in an emailed PDF.

The results…
First, the bad news: the paint on the woodwork and the dust in the window sills have a whole lotta lead. We pretty much assumed as much—in a hundred-year-old house, it would be unusual for glossy trim paint not to have lead in it—but now that we know for sure, I’m having to rethink my strip-the-woodwork project. Lead, like asbestos and other icky airborne things, is not especially dangerous if it’s adhering properly to the painted surface (and you’re not licking it), but if it starts to flake off or chip and create paint flakes or dust that can be inhaled or eaten by small children or pets, it’s a bad scene. And you’re not supposed to remove high lead paint with a silent paint stripper (which was my plan), and I really don’t want to mess with the toxic chemical agents that can remove it safely.

But happily, there was good news too. Specifically, the paint and plaster in our kitchen do not have lead in them to speak of—and that’s very good news, since someday soon we’re hoping to tackle the kitchen renovation, and it will be infinitely easier to attack the woodwork and wall demolition if we aren’t simultaneously worrying about lead abatement and controlling lead dust.

And, perhaps even more importantly, our soil—all of it!—passed with flying colors, with everything testing on the very low end of the “lead safe” category (150-500 ppm). (In fact, the lead levels were barely higher in the soil from the ground than in the potting soil from the nursery that I threw in as a control. That may say more about the nursery soil than about our soil, but there ya go….) This is especially good news because it means we can begin to plant veggies in other areas of the yard, and we also don’t have to worry about trying to make the yard lead-safe (which would be a frustratingly painful process, since you basically have to dig everything out and replace the soil). So that was very welcome news.

…and what to do about it!
Based on this news, I’ll be repainting the woodwork in the dining room with a safe high-gloss paint to seal all that badness inside—and, of course, leaving a note for future owners that stripping the woodwork is probably not the bestest project to take on! (This is probably not the end of the world, since I’ve recently discovered that past owners of our house were—how shall I put it—“creative” (and resourceful!) in cutting out the woodwork when heat was installed, and consequently there’s not much to restore near the heating vents. And when my woodworker uncle came to visit a few months back and checked out our front door—nicely stripped—he noted that it had clearly been intended to be natural wood on the outside, which is apparently a quarter-sawn oak veneer, but not on the inside, which is plain old Doug fir. Ah well.) Luckily, we also own a HEPA vacuum, which is the best way to clear a home of dust and paint chips.

I’m still undecided on the living room, where the paint is stripping pretty cleanly, the wood is in better shape (and was nicer to begin with—beautiful elm and quarter-sawn oak) and there might be some merit to finishing the project. It’s just that it’s a very, very BIG project—and we already have a lot of other big projects to contend with right now. On the other hand, I don’t want to repaint if we might really strip it all at some point, because that just creates more unnecessary work. We’ll see.

This has some implications for our window project, too. The dust from our window troughs also tested high (not as high as the paint itself—but still high enough above the “safe” level to be of concern). Again, not terribly surprising, but something to think about nonetheless. One big source of lead dust in old houses is windows and doors opening and closing—and one good way to get rid of this problem is to replace the windows. So as we work through our window rehabbing and replacement work, we may decide to replace all of the bedroom windows instead of just the two with dry rot to ensure that none of the bedrooms have lead problems. If I can find a good place that will strip the windows, I may go that route as well. We may also re-prioritize to do these in order of use rather than in order of condition. A few of the windows have also had strips of unpainted wood set into the side jambs, which I think was intended to facilitate movement (or replace rotting wood perhaps), but has the added benefit of eliminating one of the two pieces of lead-coated wood that meet each time the windows open.

How much lead is too much?
The most confusing part of the lead testing, at least for me, was figuring out how much lead was too much lead. The kit we got came with baselines for safety, but I found some of them a bit high. ACLPPP uses 1,000 ppm as the “safe” threshold for soil, for instance, and 250 ppm for child-safe soil; in contrast, the state of Minnesota uses 100 ppm as their threshold for bare soil (although they don’t require soil above that level to be removed unless there are visible paint chips). The EPA claims you can plant in soil under 1,500 ppm, except for root vegetables, which you should grow in soil under 1,000 ppm.  Other sources say you can garden under 500 ppm; others say no, only garden if the soil tests under 100 ppm. (Notably, even our nursery soil came in at 140 ppm!)

So what’s really safe? With the information we have, I feel comfortable using our general soil (which tested in the low 200s) for everything except for leafy vegetables and herbs. (Fruiting plants and other plants where the edible components don’t grow directly in the ground don’t absorb as much of the lead and other soil contaminants as leafy vegetables and herbs; with root vegetables, the contamination is largely from surface contact, so you can mitigate this by simply peeling and cleaning these vegetables.) We’ll continue to grow those higher-risk plants in our raised beds with nursery soil (even though this will screw up the crop rotations—argh!)

It’s a little more straightforward on the paint front: this summer the “lead-free” standard for new paint dropped to 90 ppm (down from 600 ppm up until this year), and the feds define anything above 5,000 ppm as being “high lead.” Since our kitchen and trim paints came in at 150 ppm and 7,500 ppm respectively, there wasn’t much fuzziness there! (What to do about the high lead paint is another question altogether—and there are just as many schools of thought on that as there are on the gardening!)

Want to get your own lead test kit?
If you live in Alameda County, you can check out the ACLPPP site for more information on ordering test kits or having someone come out to your home to do a free inspection. (These resources are geared towards homeowners, but there are programs for renters and landlords as well.) The cities of Oakland, Berkeley, Alameda, and Emeryville also have a variety of programs to pay for lead remediation and other work; information on those is also on the ACLPPP site.



  1. We eat a lot of leafy stuff from the garden–lettuces, chard, spinach. Over the years I probably have replaced most of the original soil, although I still dig into that clay under everything. Should I worry about compost? Or the stuff I amend with from home Depot?

  2. I wouldn’t worry about it where you are—we were mainly concerned because of how close our house is to Oakland’s Auto Row (and how old it is—you’re much less likely to find lead paint in homes built after 1960, and that in turn ends up in nearby soil). Plus you’ve been eating the veggies for years with no problems, right??

  3. Does dementia count?

  4. Great rundown on the dangers of Lead. At least the city has free info about it.

    Since you’re in the East Bay we thought you might find this list of diy resources helpful.

  5. glad to have helped and glad to hear your garden levels were good.

    btw, the original red coating on the concrete that is common on north oakland driveways and stairways is off the charts for lead. probably why the stuff still looks decent 50 years later.

    different topic: tried and failed to drill a well last week. who’d have thunk that parts of temescal have hard sandstone just 17 feet below grade. (well, actually it was a distinct possibility)

    spoke to someone working on the new kaiser building before i drilled. his crews went down and down many feet without hitting bedrock. contaminated ground water, yes. but lots of it.

    -len raphael

  6. re. raised beds for growing vege’s: any links to faq’s on comfortable dimensions etc.?

  7. I think a few of our gardening books touch on this, and you can probably Google for a range of opinions—I’ve heard 4’x6′ often, though. Ours is 6′ x 6′ and definitely too wide to reach into comfortably (just too much of a pain to empty the soil, cut it, and refill!) A lot of people also do 6′ x 2′ in rows, too. Depth depends on what you want to grow—but a lot of veggies require at least a couple feet, so if you’re not digging down into the soil below, you’ll need to make sure they’re tall enough. We have a shallow bed for greens and a deeper bed for “real” vegetables.

  8. searched around, talked to a gal at eastbay nursery. sounds like 12 to 18 inches of soil depth for boxes that are isolated from the ground soil would be more than adequate for everything except potatoes. than it gets into whether you plan to sit and weed, kneel, or stand and bend.

    some people who prefer or have to stand etc. go for the 3 foot deep bed frames but just put inert stuff like gravel and weed fabric in the bottom half to take up space.


  9. bought three cu yds of compost from Waste Management a couple of months ago. very odd smell and very warm. comparable price to American Soil or Acapulco Soil in Richmond.

    for some reason my dog loved it. got me thinking about all those dog people who throw their dog’s poop into the green recycling bins. then Waste Management composts it.

    My understanding is that near impossible to quickly compost mamal poop safely because of high bacteria and protein levels. I’ll talk to Waste Management to get their explanation.

    -len raphael

  10. found several commercial dog poop composters which all required pricey enzyme supplies.

    found a nifty design for a solar powered self contained outhouse, which uses solar heat to raise the temp high enough to kill the bacteria etc.

    then a very recent national geographic piece on SF trying to do special separation of dog waste to try methane production. quoted a stat of 3.8% of total? garbage in sf was dog poop. i could believe its high. http://news.nationalgeographic.com/news/2006/03/0321_060321_dog_power.html

    is Waste Management doing any of this or just mixing it all up with some dirt that hasn’t been tested for anything, and reselling it?


  11. Waste Management asks people not to put dog waste into the green bin, but to put it in with the regular garbage instead—so I assume their composting method doesn’t accommodate it. Sad for us (and for the crew who picks up our trash!), because that ends up being half of what’s in our trash in any given week.

    I did look into composting the dog waste in the yard at one point, but almost none of the commercial composters work in clay soil, unfortunately, and since they also can’t be near edibles, it wasn’t so helpful.

  12. there’s a short paragraph in Drip Irrigation by rbt kourik on the use of cisterns/rain barrels to the effect that runoff from composition (most common pitched roof shingle material) has a higher than desirable level of lead and some other metal. his point being you wouldn’t want to drink the stuff, but he opined it was ok for watering food crops.

    in a chapter on grey water systems, he seems to think they’re currently incompatible with low maintenance drip systems: clog the systems too easily.

    btw, i still don’t get the usefulness of rain barrels around here, unless you have a small cactus garden, or a half acre’s worth of barrels uphill from your modest garden.

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