High lead levels an issue for backyard chickens, soil

Chicken by Will Merydith

The number of backyard chickens in Berkeley is on the rise, and lead in the soil is something their owners need to know about. Photo: Will Merydith

Last month a local veterinarian had a Berkeley client bring in a very sick chicken.

“It was almost dead,” said Dr. Lee Prutton, of the Abbey Pet Hospital in El Cerrito. Prutton said he put the chicken to sleep and, wondering if it had a contagious disease, sent the body to the state lab for testing. The results: heavy metal poisoning, mainly lead.

The vet is now concerned that people are raising chickens in lead-contaminated urban soils, unaware that the lead can enter the chickens’ eggs that we eat.

Lead poisoning can cause brain damage, miscarriage, high blood pressure and learning and behavior problems, and is especially problematic for growing children, according to the Alameda County Healthy Homes Department.

Last October, the New York Times reported that “…a New York State Health Department study show(ed) that more than half the eggs tested from chickens kept in community gardens in Brooklyn, the Bronx and Queens had detectable levels of lead, unlike store-bought counterparts.”

A study in the 2003 Journal of Veterinary Diagnostic Investigation confirms the transmission of lead from a chicken to its eggs.  According to ‘Lead Contamination of Chicken Eggs and Tissues from a Small Farm Flock,’ “The data show a strong positive correlation between (chickens’) blood lead and the concentration of lead in the yolk of eggs… Eggs and chicken tissues containing significant concentrations of lead are a potential human health hazard, especially to young children.”

In Berkeley, backyard chicken keeping is on the rise, but how many chickens are out there is unknown, since licenses are not required. At the Urban Farm Store at BioFuel Oasis on Sacramento and Ashby, a clerk says they sell about 20 bags of chicken feed a day. She estimated at least 500 households in town are raising chickens.

So lead in the soil is something those chicken owners need to know about. It’s also a concern for backyard gardeners, of course.

But Daniel Miller, executive director of Spiral Gardens, the community garden on Sacramento Street, cautioned about being too worried. “It is something we need to be educated and concerned about, but not something to be alarmist about.”

Lead, more than the low, naturally occurring amounts, is all around us in an urban setting, Miller said. The question, he said, is, how much, and how to remediate it.

Ruby Blume, at Oakland’s Institute of Urban Homesteading, agreed. Blume said she gets a lot of questions about lead in soil and has posted an article addressing the issue on the Institute’s website.

Lead can get into soils from lead-paint chips from buildings, past industrial use of the land, and auto fumes. Step one is learning about one’s soil.

Miller said when the Sacramento Street garden was founded in 2004 they tested the soil, which turned out to be fine.

Berkeley’s Ecology Center provides a list of soil testing organizations.

Miller says he likes the University of Massachusetts lab, which is relatively cheap (as little as $9) and provides a comprehensive report, giving the parts per million (ppm) of lead in the soil.

Chickens love to peck in the dirt and dust-bathe. Owners are advised to get their soil tested. Photo: Nancy Rubin

Lead levels of 300 to 600 ppm are typical in East Bay soils, according to Blume. (Naturally occurring levels – of non-toxic lead — are 10 to 50 ppm.)  Up to 300 ppm is considered “a safe level” for growing produce, according to the University of Minnesota, but 400 ppm is the “hazard level for bare soil in play areas,” according to federal and state agencies.

That doesn’t mean 400 ppm is necessarily unsafe for growing plants. In such soil, Blume said, almost no lead reaches the fruit of the plant – such as an apple, zucchini or tomato. Very little reaches the leaves or even roots, she said. The biggest danger to the consumer is eating contaminated dirt clinging to the plant, so leafy greens should be washed well. Root vegetables should be washed and peeled.

Soil with higher levels of lead can be remediated with fish bone meal or compost. The phosphates in these materials bind with the lead, turning it into a non-toxic form, Blume said. Planting in raised beds also alleviates the problem.

Blume said she doesn’t think lead need be a huge concern for gardeners, and that she’s more concerned with chickens. Chickens love to peck in the dirt and dust-bathe, she said. She advised people raising chickens to get their soil tested.

Providing a barrier of wood chips or mulch between the chickens and the dirt can lessen the contact with lead. At Spiral Gardens, Miller said, years of composting have built up 2 feet of new dirt under the chicken run.

On Saturday Sept. 7, Miller is giving a free class at Berkeley’s Ecology Center to address gardening and heavy metals. He will cover how to test soil, how to interpret the results and how to remediate. He is also happy to discuss raising chickens, if people would like to, he said. For more information on the class, visit the Ecology Center website. (Register for the free class in advance so the organizers have a head count.)

Local organization that offer information on gardening in soils with lead: 

Rosa Parks chickens found dead, buried on campus 06.12.13)
Thief steals 2 school chickens from Rosa Parks campus [06.07.13]
Pets abandoned in Tilden can become dinner for predators (05.02.13)
Podcast: Ain’t nobody here but us chickens (07.26.12)
Chickens let loose on Berkeley High campus reunited with owners (06.14.11)

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  • Guest

    There may be lead in the soil on which Berkeley chickens are pecking around, and we know lead is bad, but is there any evidence to suggest the lead is showing up in the actual eggs?

    The article sort of approaches this topic at the beginning: “The vet is now concerned that people are raising chickens in lead-contaminated urban soils, unaware that the lead can enter the chickens’ eggs that we eat.”

    So can it? Is it? All of the labs listed on the Ecology Center’s website test soil for lead, but can they test eggs for lead?

  • Gregory Lemieux

    I called the State Department of Toxic Substances Control and they recommended calling contacting the UC Davis Vet Med lab (http://www.cahfs.ucdavis.edu/contact/index.cfm). The very helpful woman on the phone confirmed that they would do a broad spectrum heavy metals test on all or part of the egg for $31.70/test.

  • gimpytroll

    B-b-but muh urban farming!

  • Public Health Professional

    It is completely untrue that lead in soils do not accumulate in the leaves of plants. It is not ever a good idea to eat leafy vegetables grown in lead contaminated soils. Additionally, we onow that lead accumulates in the body and is transmitted to eggs therefore by extention if their is lead in the soil where chickens are being raised it must be remediated. I spent many years working in Lead Poisoning Prevention and find it completely irresponsible to quote gardeners on a medical and scientific public health issue as though they are an expert. Please do not propogate this type of misinformation that puts young children at risk. Please contact the Childhood Lead Poisoning Prevention Branch of the State Dept of Public Health. It is great to make folks aware of this problem and no, we don’t want panic. But neither do we want folks to ignore an identified danger by downplaying the effects. Young children are at high risk of lead poisoning and this is a serious issue.

  • hmm…

    Blume’s information about lead comes in part from the public health professionals at the EPA. See his report that Berkeleyside linked.

    People who don’t farm and who naively let their kids play in the yard may be taking on a much greater risk.

    Quoting the report.

    “The good news is that this same amount of lead (300-600 ppm) is low risk for gardeners and food grown in urban gardens, given implementation of “best practices” based on understanding where the actual risks lie. Steve [Calanog, a regional On-Scene Coordinator for the EPA] said that you can safely eat food grown in soil with up to 300 ppm lead, if you follow a few simple guidelines.

    How can this be? Well, first of all, it is important to understand that not much of the lead present is bio- available to the plants. Only 1% of the lead available can be taken up by plants. So even if your soil tests at 300 ppm, the actual risk based on plant uptake is 3 ppm. Most of this will be found in roots and stems. The amount of lead found in fruits is fractional and close to zero, even in highly contaminated soils. The lead just doesn’t make it there. So if you have lead in your soil, you should plant fruit trees, cane berries and plants with accessory fruits like tomatoes, peppers, squash etc. There is a much higher danger, especially to children, of lead poisoning from ingesting the actual dirt. In leafy greens the biggest danger is from dirt splashed onto the leaves–not so much from lead inside the plant. So wash your leafy greens well! Root crops pose the highest risk, as they will uptake some lead and the dirt is present on the skin of the root. So if lead is present in your native soil, always peel root crops or grow them in imported soil (raised beds).”

  • skeptic

    “But Daniel Miller, executive director of Spiral Gardens, the community garden on Sacramento Street, cautioned about being too worried. “It is something we need to be educated and concerned about, but not something to be alarmist about.” Can you imagine if a big company made a similar claim?

  • skeptic

    I’m guessing you are probably right, but, again, can you imagine how this issue would be handled if the urban farmers were companies? I can see it right now, hmm…, “I don’t care what your “science” says, I feel in my heart that the lead made me sick.” “Can you prove to me that the lead actually is safe?”.

  • Thanks for your thoughtful question, guest. To be clearer, we have added a link to a study which confirms the transmission of lead from a chicken to her eggs.

  • PragmaticProgressive

    Daniel Miller’s a resourceful fellow. Somehow his kid attends Berkeley schools even though he lives in Oakland, according to Berkeleyside. http://www.berkeleyside.com/2010/07/30/berkeley-bites-daniel-miller-spiral-gardens/

  • PragmaticProgressive

    Didn’t the council recently change city code so that urban farmers could sell their produce?

  • Yale Cohn

    The care and raising of chickens may be more problematic than has been advertised.


  • guest

    And for heaven’s sake, if you are having remodeling or painting done (or are doing it yourself) on your property), hire a EPA RRP licensed professional, and make sure they take appropriate remediation measures.


    Also, the Alameda County Healthy Homes Department (formerly ACLPPP) is a good resource for information and training


    (And please overcome the stigma of complaining to your neighbors or the authorities if your neighbor is gutting their kitchen with an Arizona contractor who has put a fan in the window to blow the annoying dust onto your Tibetan neighbors’ kids’ play area… fines can run to $37,500 for each offense, and there can be multiple offenses per job)

  • guest

  • guest

    Looks like we have an unlicensed polluter reading the thread. Welcome, polluter!

    I’m not surprised you’re threatened by the idea of people standing up for their rights not to be victimized by those who sell their services as “cheap” by cheating on safety regulations. We should all be free to pour motor oil in the storm drains, too, probably.

  • mob mentality

    Quick, get the pitchforks!

  • oh come on

    free speech =/= kitchen remodeling + unsafe practices

  • I know, right?

    Usually the TP’s go for the “Nazi” non sequitur, I guess the “Obama” non sequitor is an improvement, LOL.

  • Guest

    Lead poisoning in backyard chickens have been diagnosed with increasing frequency in CA through the CA Animal Health and Food Safety Laboratory. A recent article highlights a few cases and that it is possible that consumption of one single contaminated egg per day can pose a health risk. The lab in Davis provides testing for lead of eggs and other samples as a routine service.


  • The_Sharkey

    Or instead just start charging people who don’t live in Berkeley – like Daniel Miller of Spiral Gardens – a fee to enroll their children in our schools. At the very least people who live outside Berkeley and want their kids to enroll in our schools should have to pay the same taxes and fees that Berkeley residents do.

  • The_Sharkey

    Are there a lot of contractors from Arizona working in Berkeley? That seems like one hell of a commute…

  • guest

    It seems completely inappropriate to fling accusations about someones children just because they are quoted in the paper.

  • PragmaticProgressive

    You are mistaken. Both of these facts – that a) Miller lives in Oakland and b) sends his kid to Berkeley schools – are from the article. Nobody is digging up dirt on him: he offered the information all on his own in an on the record interview. This is an admission by Miller, not an accusation by me.

    Now for all we know, Miller was resourceful enough to obtain a permit to enroll his kid in Berkeley schools. Since he describes dropping the boy off regularly, it is unlikely that there is a relation in Berkeley with a caregiver permit. And he’s probably not homeless. All we know is that he’s of those people who’ve divested from the schools in the city where they’ve chosen to live. That is a strange platform for social justice.

  • sense of decency?

    Will you be using the “public record” excuse to speculatively attack his family and stigmatize his children every time his name comes up? Do plan to continue to make off-topic insinuations about his character unless he offers more personal details for the public record?

  • PragmaticProgressive

    Tom, do you plan to continue posting on a site where you’ve been banned, twice? Do you plan to continue doing so despite not having received the apology you insisted on?

  • guest

    Weasel words!

  • Biker 94703

    It’d be helpful to this story to know if the owner had their soil tested for lead or if their children liked to feed the chickens bird shot. Dead chicken with lead-poisoning is just data point number 1.

  • PragmaticProgressive

    which ones specifically? Or do you just disagree viscerally and yet are incapable of finding a basis for doing so?

  • JoeWalsethSFDPH

    Readers should be aware that agricultural testing laboratories may not be accredited to test soil for lead. Only an EPA certified lead testing laboratory should be used for soil lead testing. The link for this list is
    Joe Walseth, San Francisco Dept. of Public Health, Childhood Lead Prevention Program