Saturday, April 4, 2009

The Chicken That Laid Leaden Eggs, and Other Horror Stories

I have become interested in raising urban chickens as part of my strategy for decoupling myself from the breaking system of the “official” global economy while living more sustainably. Thus I recently found myself at an urban chicken-keeping class which covered various aspects of the subject, including building backyard chicken coops. During the class, one student mentioned a rather disturbing article that was published in the Portland Tribune on 26 March, titled, “Chickens Eating Lead Not So 'Sustainable.'”

It seems that this article is a response to the explosive popularity of the “urban chicken-keeping movement” in our fair city, and is a criticism of that trend. The author, Tamara Rubin, stated that there is a high risk of lead contamination of the soil of most Portland home lots, due to the lead paint that was used on homes built or painted prior to 1978. She also stated that it takes only two grams of lead dust to heavily contaminate an area the size of a football field. She asserted that chickens on farms are typically less likely to ingest lead, due to the non-lead-based paint used on barns and farms, as well as stating that “most free-range farm chickens and eggs are therefore lead-free.” After giving a few short, general suggestions for testing soil and siting a chicken coop, she concluded by suggesting that the better alternative to backyard chickens is to “[buy] locally farmed, organic, free-range eggs from the store and don't risk inadvertently poisoning your own children in the name of personal sustainability.”

This article hooked my interest, though perhaps not in the way that Ms. Rubin had intended. My interest is always piqued when I hear people warning me or other ordinary citizens away from specific steps toward self-sufficiency. My response is always to ask, “What's really going on here? Is what I'm hearing true? Even if it is true, is it the whole story? Why am I being told these things – especially now?” It was with these questions in mind that I began to study the issue of lead soil contamination in urban areas. This is what I found:

Is It True?

It is a fact that many older urban neighborhoods in the U.S. have soil that is contaminated by lead. The sources of contamination are lead compounds from automobile exhaust and industrial processes, and lead paint on older buildings. The lead from car exhaust was generated by the burning of leaded gasolines, which were gradually phased out in the U.S., starting in 1973 and ending with a complete ban of lead as a component of automotive gasoline in 1996. However, leaded gasoline is still allowed in aircraft, off-road vehicles and farm equipment. The sale of lead paint for residential use was banned in the U.S. in 1978.

Because of the high concentration of heavy industry and car traffic in older inner cities over time, soil lead levels have built up to very high values in these places. The United States Environmental Protection Agency standard sets a maximum “safe” soil lead level of 400 parts per million (PPM) in areas where children are likely to play, and 1,200 ppm elsewhere. As a reference, lead levels in virgin, uncontaminated soil range from 20 to 50 ppm. In cities such as New Orleans, Boston, Detroit and Philadelphia, soil lead levels of nearly 2,000 ppm can be found.

These heavily polluted areas are where poor and ethnic minority populations have historically been concentrated. The small children of these neighborhoods absorb lead via breathing dust and windblown dirt from bare lots, or by ingesting dirt. They frequently suffer central nervous system disturbances as their blood lead levels build to very high values relative to the general population. The children of some of these cities have rates of chronic lead poisoning that are ten times higher than rates of children in affluent suburban neighborhoods.

The lead contamination problems found in older American inner cities is greatly amplified in the cities of the developing world, where environmental and health regulations are much more lax than in the U.S., and where large multinational corporations have moved most of their dirtiest manufacturing operations as a result. The environmental damage wrought by lead pollution prompted this quote from Caltech geochemist Clair C. Patterson: “Sometime in the near future it probably will be shown that the older urban areas of the United States have been rendered more or less uninhabitable by the millions of tons of poisonous industrial lead residues that have accumulated in cities during the past century.” If this is true of the United States, it is true in spades of many places in China, India, South America and other places of outsourced manufacturing.

Lead And Urban Agriculture

Is there a danger then to those who raise their own food in their own backyards? Not as much as one might think. Many studies of this subject have been performed by many groups, including U.S. Government scientists, local universities, local non-profit food security and urban gardening groups, and public-private partnerships between two or more of these agencies. In addition, studies have been performed by NGO's and governments of other nations where lead and heavy-metal soil pollution is a problem. These groups have discovered that lead is not readily absorbed by many plants, nor is it readily concentrated in their tissues to a significant extent. (There are some notable exceptions, however.)

A 2003 study titled, “Lead Levels Of Edibles Grown In Contaminated Residential Soils: A Field Survey,” by Northwestern University, found that those plants that in any way took up or concentrated lead in their tissues did so in their roots first and foremost. Thus, root vegetables such as carrots or onions might absorb between 10 and 21 ppm from growing in highly contaminated soil. Plants were less likely to concentrate lead in their shoots or leaves, although some leafy vegetables like mint had leaf lead levels as high as 60 ppm. Lastly, the fruit portion of fruiting vegetables like corn, beans, grapes and other varieties was least likely to absorb or concentrate any lead. Mitigation of risk from eating these vegetables was easily handled by thorough washing with soap and water. In addition, the 2005 study “Sources, Sinks and Exposure Pathways of Lead In Urban Garden Soil” by Wellesley College concluded that a small child's standard serving of garden vegetables would contribute no more than 10 to 25 percent of the lead found in that child's standard daily portion of tap water.

Then What About Urban Livestock? (Specifically, Chickens)

I was only able to find two studies that directly examined lead uptake and concentration in tissues of chickens. One study, “Lead Contamination of Chicken Eggs And Tissues From A Small Farm Flock,” was cited by Tamara Rubin on her website about lead poisoning, and dealt with chickens that had actually eaten chips of lead paint from an old farm building. While the report states that lead tissue concentrations rose as high as 1,360 parts per billion for the livers of these chickens, concentrations in the eggs of these chickens rose no higher than 450 parts per billion. This study did not analyze the uptake of lead by chickens from polluted soil.

The other study is titled, “The Content of Cadmium And Lead In Muscle And Liver Of Laying Hens Housed In A Copper Industry Region,” and was published by the Agricultural University of Wroclaw, Poland in 2005. This study tracked the lead uptake of two sample groups of hens raised in a region that had formerly been mined for copper, with resulting heavy metal contamination of the soil. This study found that free-range hens and their eggs were likely to have higher concentrations of lead and other toxic heavy metals than their caged counterparts. The weakness of this study is that measurements of soil metal levels were not included, nor were they correlated with the locations of the flocks studied. Therefore, it is not possible from this study to plot the relationship between specific levels of soil and environmental heavy metal pollution and heavy metal blood and tissue levels in chickens raised in this environment.

These studies do indeed show a correlation between environmental sources of lead and increased concentration of lead in poultry tissue. However, these sources do not show the correlation as clearly as it should be shown, especially for lead uptake by poultry on contaminated soil such as is found in urban environments.

There is one other thing to mention, namely that even on regular farms, animals and poultry are being exposed to heavy metal poisoning through exposure to pesticides and inorganic fertilizers. Being on a farm is not necessarily safer in this regard.

Remedies For The Urban Homestead (The Other Side Of The Story)

When one reads Tamara Rubin's writings, as well as the sources I have cited above, one can get the impression that urban gardening and self-sufficiency is scary and dangerous, and that one is better off continuing to rely on the official food system. However, such a conclusion ignores several facts. First, non-profit urban gardening groups and scientists from universities have studied strategies for making urban gardening safe even where soil is contaminated. Northwestern University has published the following recommendations for urban gardeners:

  • Survey the property to determine the potential lead hazards, extent of the contamination and location of high-risk areas.

  • Plan to locate fruit and vegetable gardens away from buildings, especially if peeling paint is evident and sites where sludge with heavy metals was applied.

  • Analyze lead concentration in soil samples from areas where vegetable gardens exist or are planned.

  • Do not grow food crops in a soil that is contaminated to levels greater than 400 ppm. Instead, use either containers or construct raised beds, with a semi-permeable barrier between the clean and contaminated soil.

  • Where container or raised bed gardening is not possible, fruiting crops should be grown.

  • Root vegetables, leafy greens and herbs should not be planted in contaminated soils.

  • Test new topsoil before using it and annually retest the garden soil to monitor for recontamination.

  • Do not use plants grown in contaminated soils for compost.

  • Use mulch or a weed tarp in garden beds to reduce the potential for aerial soil dust deposition or soil splash up on crops.

Others have studied the effect of adding various soil amendments to reduce soil lead bioavailability. One such study, conducted by Hangzhou University in China, discovered that adding phosphorus to lead-contaminated soil bound the lead and made it insoluble, thus less able to be absorbed by plants. Other studies have shown that adding raising soil pH or adding compost and manure to contaminated soil reduces the bioavailability of lead. Lastly, there are agencies who are studying phytoremediation techniques, where specially selected plants are used to draw lead out of contaminated soil in order to reduce total soil lead concentrations. While the other techniques have documented success, phytoremediation is still in an early, experimental stage. And as for chickens, there are several very simple strategies that can be employed in the building of their coops and runs to keep them from coming into contact with contaminated soil.

But before anyone rushes out to secure remedies for soil contamination, the first step is to get your soil tested by a reputable laboratory. It may be that you live in an area that is not heavily polluted.

Conclusion: Bustin' Loose From The System

Having examined the evidence behind Ms. Rubin's article, I believe that she does raise some legitimate concerns regarding lead contamination of urban soils. However, I disagree with the tone of her article, because it forces ordinary, average people of small means into a corner. These are the people who are being squeezed and bruised by their continued reliance on the breaking system known as the official economy. Last year, most of them found it increasingly hard to afford food and fuel as resource shortages led to skyrocketing prices. Most of them even now are being crushed by the weight of unsustainable debt. Very soon they will be squeezed yet again by rising food prices. Midst all of this, they are losing their jobs at a terrifying rate.

What shall we say to such people? “Don't garden; don't raise urban livestock, don't try to be self-sufficient; it's too dangerous”? Shall we tell people that they can only get their food from the store? Shall we pass laws making self-sufficiency illegal? That will go over about as well as a lead chicken. We can't not garden; we can't not keep urban chickens; we can't not learn self-sufficiency. We have to pursue these things. Rather than trying to scare people away from self-sufficiency, let's work on fixing that which has become so broken, while going after the people who did the breaking in the first place.

I'd have been much happier with Ms. Rubin's article if she had mentioned the public/private partnerships between Government and University researchers and urban food security non-profit groups to find remedies for lead soil contamination. I'd have been much happier if she had suggested pressuring the government to make urban polluters clean up urban neighborhoods instead of trying to scare people away from raising backyard chickens. The truth is that the city is where most of us will take our stand, where we will rise or fall in our efforts to carve out a meaningful life to hand down to our descendants amid the crises now converging upon us. We can't all run away to the farm, nor can we continue to rely on a breaking system. As Bruce Sterling said, “The ruins of the unsustainable are the 21st Century's frontier.” We're starting to live in those ruins now. That's where the new pioneers will make their stand. Whatever's broken, it will be up to them to make it work. There is no other choice.



curiousalexa said...

I am a newcomer to your site, and compliment you on the research and thought you put into your essays. This is the type of work I enjoy reading, and look forward to continuing opportunities to do so!

Kiashu said...

As you point out, the sort of people who are really under some threat of lead in their soils are just the sort of people who can NOT afford "locally-farmed, organic" food.

So instead they buy food from the industrialised system, which is hardly without risks - spinach, tomato, and mad cow disease, anyone?

There are so many environmental dangers to people, dioxins in the water, phthalates in the plastics, particulates in the air, I really can't see a bit of lead in the eggs as a huge jump in danger.

It's funny how all the dangers of the industrialised system are glossed over or ignore in articles in the mainstream media, but the instant people start trying something self-reliant, it's all doom and gloom.

It's almost as though they didn't want people to be self-reliant, and wanted them to continue relying on an industrialised system. The industrialised system which pays for advertising in the newspapers and magazines where these articles are published.

Naw, they're being completely honest, I'm sure.

Jennifer said...

Thank you for this very interesting article. I have backyard chickens and a three-year-old who eats them on a regular basis, so I've been thinking about this issue a lot since reading Tamara Rubin's article. Her article honestly scared the heck out of me - but more than that, it shook my faith in there being *any* safe food to eat. I recently told a friend that I think backyard chicken eggs (were) one of the few guilt-free foods left on the planet (assuming you treat your chickens well!). Now I'm not sure if I can say that.

On the other hand, when I read the original article I missed the implication of 440 parts per *billion* in the most contaminated eggs. If regular, uncontaminated soil can have 50 parts per million of lead, then a contaminated chicken egg is still vastly less contaminated than healthy soil. Of course, we don't regularly eat dirt, but this does help put things in perspective.

Obviously, eating any lead at all is a bad idea, but it would be useful to know what levels of lead are actually considered dangerous; how long lead stays in the system (if my chickens ate all of the tasty lead paint chips around my house two years ago, are they still "hot"?) and how much factors like proper nutrition protect people from lead absorption. I understand that a healthy diet does offer a fair amount of protection.

Anyway, thanks for the opportunity to mull this over. I am going to get my daughter tested for lead (something I should do anyway). Meanwhile I'll probably eat a few egg-white omelets and then gradually go back to my high-octane backyard eggs.

It is amazing and disappointing how much energy one can spend on trying to minimize each and every risk in life. Many moms - myself occasionally included - seem to revel in it. The challenge is finding perspective.

TH in SoC said...

Jennifer, thanks for your readership. I think there's a lot of fear-mongering nowadays (not all of it intentional), the aim of which is to scare ordinary people away from self-reliance and toward continued reliance on the breaking "official" systems. Prudence is necessary; however, a little research can go a long way toward countering the fear-mongers.

Tamara Rubin said...

Hi. I'm very tired right now (it's tiring being the mom of a bunch of little boys with lead poisoning) but I wanted to thank you for taking the time to read my piece and to so thoroughly and thoughtfully respond. I may post another comment later too as I am sure I will forget something I wanted to say right now - but, primarily, I wanted to say that the piece I wrote got the job done - it started several interesting conversations on the subject AND at least one mother promised to get her child tested as a result and at least one person decided to get their soil tested. I am not an alarmist and I come from a farming family and am all for local/ sustainable/ home gardens, etc. I just think all consumers (even the consumers of veggies and eggs from their own yards) need to have the tools to be well informed about a subject and somehow expired generational memory has dropped most consideration for lead poisoning off of people's radar for concerns. Also - there is NO safe level of lead for a child and NO threshold for safety so any amount of lead is toxic and preventing ANY lead from entering a child's body is possible so it should be done - testing the soil is a simple option for keeping those backyard chickens in a safe sustainable environment and protecting the children who live there at the same time. While your post notes that contaminated soil levels can be 2000 ppm - please note the home renovation case in New Orleans where her soil was over 100,000 ppm - and my soil here in Portland was between 3000 and 5000 ppm after the ordeal when the contractor poisoned our home and children. Test, Test, Test - research - and stay informed. Also some crops are being used to clean soil in New Orleans and elsewhere because of how well they absorb lead from the soil (Sun Flowers / Spinach) - so be careful about your backyard crops. And finally - maybe finally - please try not to read "tone" into people's articles - my article did not have a tone - I had back yard chickens and love them and think they are cool and a great opportunity .... my article had a message and an intention - which are distinctly different from a "tone" - message: be aware of what you are putting into your children's bodies - understand, and research things before making assumptions. Also - one point that was mentioned - that organic eggs (locally farmed, whatever) are not cheap - I would like to offer for your consideration that, based on the humble mere observations of a local urban resident (me) the people that mostly have urban chickens here in Portland do so not as a cost savings measure - and are more often than not middle income families - the same demographic that is unknowingly poisoning their children through home renovations (because this is a demographic that has not been educated about lead poisoning - a wholly preventable and painfully permanent life altering problem that causes a host of learning and behavioral disabilities in young children and then the adults that they become- lead poisoning prevention education continues to be directed at low income minorities in rental housing - and in Oregon that demographic does not even live in pre-1978 housing anymore - they live in apartments and townhomes that were built in the 1980s and 1990s.. My website has lots of pages to answer questions on the subject. Also - you mentioned a lot of points you wish I had mentioned in my brief article - while they are all valid - when choosing a mere 500 words for print purposes it is so very difficult to cover the full range of points on an issue - which is (again) why I created the chicken pages on my website so I could say what I had to say - and if you read those you can see that I take all this with a grain of salt, approach life with a sense of humor and only see this one issue as a means of drumming up more attention to the concern of childhood lead poisoning within the hidden demographic that it is currently effecting most (even though the parents and pediatricians of these kids have no idea they are sick because they do not fit the historical stereotype of a lead poisoned child) - Why do you think there are so many cases of ADD, ADHD and Autistic Spectrum (but not Autism) diagnosis out there! We do what we can. Email me with questions or go to my site: or
Tamara Rubin

TH in SoC said...

Tamara, thanks for your readership. I have gone back and re-read your article, and I have just one question. When you wrote the article, were you trying to dissuade people from keeping backyard chickens, or were you simply trying to help them avoid a hazard in raising backyard chickens? Thanks.

Tamara Rubin said...

Mostly just trying to get people to consider toxicity in their urban farming efforts. Ideally to get their soil tested. My husband an I re-read the article too (after reading yours) and saw how it could have been misunderstood. It really is difficult to boil things down to 500 words and say exactly what you intend to say! My thought was that most people would be worried about getting their soil tested (potential costs/ potential resultant issues/ problems/ new things to deal with), and if they were not willing (or for some reason not able) to get their soil tested, then it would be better to buy eggs at the store for the moment (until they could get their soil tested.) As you may know, Jennifer (who posted on your blog) got her eggs and child tested. She posted the results yesterday - both her eggs and her child tested positive for lead contamination. Now she has the difficult work ahead of to resolve the problem. In the end my efforts are about creating awareness that will protect children. Soil testing is a great start. If any of your readers is "low income" (at or below 80% of the median income of Portland) they may qualify for a free hazard assessment of their home including free soil testing through the program with the Portland Development Commission. I am also looking for 10 local urban chicken farmers that will volunteer to have their soil tested for free (as part of an investigative journalism style follow up article to the Portland Tribune piece - but this time in Willamette Week) So if someone wants their soil tested for free and is willing to participate in this inquiry (and has urban chickens) - they can contact me directly at Thanks again! Good conversations are always worth having. - Tamara
P.S. I posted some new information on my website today on my "thought for the day page" and also included a link to your blog (if that's a problem at all - please let me know and I will take the link down.)

TH in SoC said...

Tamara, thanks for your reply. It is now established that lead is a problem in older urban environments. Let us therefore move on to investigating how urban residents can safely and inexpensively deal with lead hazards while becoming self-reliant. In particular, I intend to write a follow-up piece sometime soon about soil remediation and urban homesteading.

Like you, I don't want to see people doing things that would expose them to health hazards. At the same time, I don't want to see people remain in continued bondage to the breaking systems of our "official" economy, including our system of food access.

Anonymous said...

Hello, thanks for writing this article. Where/how can you get your homegrown eggs tested?
thanks again!

TH in SoC said...

I'll have to look into that to get you an answer. I'll try to address that in a future post. Meanwhile, if you live in the Portland metro area, you can try asking Growing Gardens. Their website has their contact information. Thanks for reading!

todd said...

We keep chickens for eggs near our 1910 house. I had the soil tested for lead. 434 parts per million, which is 34 parts higher than the accepted "safe" level for areas children will play in. Since the chickens sure do seem to eat a lot of dirt, I had an egg tested. None detected. The testing threshold is 1 part per million. 1 part per million is considered safe for candy. Testing was done by Wy'East on SE 11th.

TH in SoC said...

Todd, thanks for your comment. It goes a long way toward dispelling fear-mongering about urban self-reliance. As a side note, in my post "Brownfield Remediation For Urban Homesteaders," I mentioned research that showed that fruit-bearing trees and plants, and leguminous plants can be safely grown directly in contaminated soil, and their edible fruit or seed pods can be harvested and eaten without worry.

Karen said...

Hi there

I've just come across your thread through a google search. I live in a formerly industrial city in Asia so this issue is of concern to me.
You wrote: "And as for chickens, there are several very simple strategies that can be employed in the building of their coops and runs to keep them from coming into contact with contaminated soil." - Just wondering if you have done a follow up post with any of these strategies?

TH in SoC said...

Hello Karen. I have not yet done a follow-up post on safe chicken coop layout and design. It is something I intend to look into, though. I have a few posts to finish on other topics first. If you don't see a post on coops within the next couple of months, feel free to remind me again. Thanks for your readership.

stickers said...

this is such an incredible article, thankyou so much. x

love2garden22 said...

My twelve 'girls' eat anything! I was sitting in my back porch when I heard a tapping sound, and they were eating the paint off of the house. We have an older wood home and the paint underneath must have lead in it. I have since blocked access off so they can't get to the walls anymore. They aren't allowed close to the house now, but I wonder if their eggs are safe to eat now?

TH in SoC said...

If you're nervous, I'd get some of the eggs tested. I am not a doctor or vet, but I would suspect that as time passes and your chickens don't eat any more paint, whatever concentration of lead remains in their bodies will decrease.

I will emphasise the point I made in the original post, that we will all have to find ways to make self-reliance work for us. Continued reliance on the breaking system of industrial agribusness-produced food is more dangerous than anything we will encounter in becoming self-reliant.

Thanks for your readership!

love2garden22 said...

Thanks TH in SoC! I still kept and ate the eggs. I felt that they really didn't eat that much (maybe an inch square) and after all these years I probably have more lead than that already in me. We are determined to be self reliant even though we live in the city. For the past six years we have planted only edibles (mostly fruit and nut trees) and it's starting to pay off. Next year's projects include bees and fish. We have so much to relearn that it's overwhelming at times. I really appreciate your point of view, and keep getting out the word. Common sense rules! Thanks, Jan

Tamara Rubin said...

Hi - your links to studies of lead in soil are great - can I post them on my website with a link to your blog?
- Tamara Rubin
P.S. if you want to get together and chat about the soil/ chicken issue - let me know. I think you read a lot into my article (last year) that was not there and not intended. It is very difficult to write a comprehensive article in 500 words or 750 words! I'm just happy that it started a discussion.

TH in SoC said...

Hello Tamara. It's fine if you want to link to some of my posts and the studies on lead that I have cited. It would be fun to get together with you some time and chat about mitigating risks in urban agriculture. And I agree with you that it's hard to put all the information one would like into a short essay.

By the way, do you know Clark Henry at the Portland Bureau of Environmental Services?

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