Lead in the dirt?

March 28, 2011 2:29 PM

Is there really a garden-ban in Portland, Maine because of lead in the soil?

I recently heard that Portland, ME has a gardening ban for edible fruits and vegetables because of high-levels of lead in the soil...

Unfortunately, my google-skills are coming up with nothing but fairly paranoid sounding blogs convinced of everything giving their children autism...I'm trying to find something a bit more balanced.

Is this true? If so how on earth did this happen and what area around the city is considered 'contaminated'? Is this common in the Northeast, or is it a unique thing to Portland?

posted by furnace.heart to home & garden (9 answers total)

Soil Lead Distribution in Portland Maine (20 MB .pdf)

Regardless of local laws/bans, you should always get your soil tested if you are planning to grow things in former industrial towns.
posted by ofthestrait at 2:33 PM on March 28, 2011 [1 favorite]

I have not heard of this. When I lived in Portland, I had the soil next to the house tested for lead. The lead was significant, due to leaded paint used prior to the 1970s and airborne lead from cars. Removed the top 8 inches of soil, laid in new soil, grew tomatoes, lettuce, and herbs. The house had been vinyl-sided, so lead from paint was no longer a big issue. The Cooperative Extension Service was very helpful.
posted by theora55 at 2:35 PM on March 28, 2011

The best answer to any "can I grow X in city Y" question is "contact your local cooperative extension service." If there's such a ban, they'll know all about it. Here's yours.
posted by deadmessenger at 2:35 PM on March 28, 2011

I just researched this recently for my own city garden -- it turns out that the problem with lead in the soil is the dirt that's on the fruits and veggies. Plants don't actually take up much of the lead themselves, especially if you add a lot of compost to the soil. So you just have to be sure to wash everything well, and wash your hands after digging around.
posted by yarly at 2:40 PM on March 28, 2011 [1 favorite]

I don't see anything about it in the City of Portland's Health Department's online lead safety resources. It's not super-likely that lead soil levels in the entire city would be high enough to require a blanket ban for the entire city. However, specific areas may be high enough to require a deed restriction, which could (among other things) restrict use for growing edible plants. (Actually, a few years back a cousin of mine worked on a summer internship remediating lead in soils in Portland; it's a known issue. But again, that was one specific area, not the entire city.)

Sources of lead in soil in an urban environment: paint chips from the chipping paint on pre-1978 housing; exhaust from pre-lead-ban gasoline; previous industrial use; high background levels (some areas have naturally high lead or other metals in soil).

If you're living in a former industrial area or an area with older housing, it's a very good idea to test soil for lead before growing anything, regardless of whether there's a ban. Your cooperative extension service can help, as noted above. (And although I really don't want to make anyone paranoid, eating the veggies isn't the only risk involved with elevated lead levels in soil-- there are also lead standards for direct contact with the soil, which are especially important if you have kids playing outside.)
posted by pie ninja at 2:46 PM on March 28, 2011

Thanks for the answers so far.

To clarify, I don't live in Portland, Maine (I live in Portland, Oregon). I've just never heard of such a thing as a grow ban, or lead levels so high in soil that it monkeys with people's ability to grow food. I just find the topic pretty interesting...I'll eventually be relocating to New England and this is just brand new information to me. Thanks for the information, and if anyone has more specific details, keep em comin.
posted by furnace.heart at 2:50 PM on March 28, 2011

I live in Portland, Maine.

There is not, to my knowledge, a "grow ban" (as in a city ordinance) that prohibits you from growing food on land you own in the city. However, as noted above, Portland is an old city, and a not-insignificant portion of it is built on a turn-of-the-19th-century landfill.

I know people who grow veggies inside the city limits, but they typically use raised beds (more from an "ability to till the soil"perspective than a lead-in-the-soil perspective).
posted by anastasiav at 3:34 PM on March 28, 2011

I live in Portland, ME and have never heard of such a thing. If there were, local community gardens like these would be illegal, and certainly not sponsored by the city as they are. Locally-grown food is a huge deal for Portlanders and Mainers in general. And as for the map that was linked, let's just say I am highly skeptical of their sampling methodology.
posted by Civil_Disobedient at 3:43 PM on March 28, 2011

I don't know about the laws in Portland, but in most of New England it makes sense to test your soil, as lead is widespread due to lead paint and arsenic in soil is naturally high.

Plants assuredly take up lead from soil, there is plenty of peer-reviewed literature on the subject (also arsenic, and persistent bioaccumulators like PCBs and dioxins). Here in Massachusetts the state just stopped assessing risk from gardening in contaminated soil for contamination clean-ups because the models show risk at low levels that are below background and therefore infeasible to clean-up.

Lead is one of the few toxic materials that we know so much about. It's almost unique in that there is no safe known levels of lead - even very low levels (below the standards) in blood show impairments in children. It's also a suspected carcinogen. Basically, I'm saying all of this because I tend not to worry too much about environmental risks because there are so many other risks in our lives, but it's worthwhile to be a little cautious about gardening in urban soils, especially in areas where lead paint was once ubiquitous. If it were up to me I'd have everyone test, or garden in raised beds/pots with clean soil.
posted by ldthomps at 5:19 PM on March 28, 2011