How safe is your soil?
In early 2009, the group sent away for a soil test that put the plot’s lead level at 219 parts per million — well under the EPA’s limit. But to eliminate any risk of ingestion, they designed a garden that would use landscape fabric and a heavy layer of mulch to cover the contaminated soil. They’d also grow vegetables in clean soil in 22 raised beds, rather than directly in the earth. With $340,000 pledged in support from Oakland’s Redevelopment Agency and City Council, the project seemed ready to go.
Except for one thing. Since the city would be holding title to the newly purchased property and therefore technically liable, it wanted to conduct soil tests of its own. These were far more involved than the low-cost, mail-away test ordered by the neighbors. Instead, the city hired a professional firm to perform elaborate soil testing and analysis at a cost of more than $5,000.
The results showed lead levels ranging between 300 and 790 ppm, all of which exceeded the applied standard of 200 ppm. The testing agency recommended that the top two feet of soil be removed and disposed of as hazardous waste, at a cost of approximately $170,000. But there wasn’t enough money in the budget, and just like that the Crossroads Community Garden was shot. The site has since been sold to a developer looking to pour a parking lot.
Resident and garden planner Pamela Campbell was disappointed to see three years of work dissolve into thin air on account of lead levels that are representative of what exists just about everywhere else in the area — especially since her group planned to cover the existing soil and grow in clean dirt. “In my opinion, it’s the same thing that you’re dealing with in all of West Oakland,” she said. “It’s total red tape. It wasn’t about food safety.”
Had the city been clear and up-front about its lead-contamination policy, thousands of dollars and hundreds of hours of work could have been saved. Likewise, if it had been willing to accept the widely acknowledged remediation strategy proposed by the neighbors, the lot would now be providing its West Oakland neighborhood with fresh produce instead of sitting fallow.
These are the dilemmas that cities and urban gardeners now face. Yet organizations like City Slicker Farms are working hard to develop safe, practical solutions to soil contamination. Since 2005, the organization has set up 170 backyard gardens, including about 140 in West Oakland, all at no cost to the recipients. The initial step is always a soil test. While few lots exhibit truly dangerous levels, most are elevated and require some form of remediation — typically, covering the soil with mulch and growing vegetables in raised beds.
“So many backyards have lead paint in [them], because lead paint was prevalent everywhere,” said executive director Barbara Finnin. “So we’re figuring out instead of digging out all the soil, how can we do that safely here?” In a two-foot-tall raised bed over an impenetrable root barrier, the risk of plant contamination is virtually eliminated, she said. Mulch as thick as six inches elsewhere in the yard helps protect children and animals from direct soil contact.
It’s a simple solution supported by urban farming celebrity Novella Carpenter, who runs Ghost Town Farms on a vacant lot in West Oakland. In her backyard, which is adjacent to a gas station, she tested and found high levels of lead. So she topped the soil with landscape fabric and mulch to protect her animals, which can bio-accumulate lead just like humans and pass them along through their meat, milk, and eggs. Yet she won’t grow any produce there. The majority of her front-yard beds are built directly atop a concrete patio that’s covered with a few inches of dirt. “It’s actually a nice thing to build on concrete,” she said — the danger of contamination is always nil.
Still, raised beds aren’t always practical, and they can be cost-prohibitive for some backyard and community gardeners to build and fill with clean soil. When the native topsoil tests at an elevated but acceptable level, the nuances become a bit more difficult to navigate.
As with lead safety levels and assessment methods, the science on plant uptake of lead from soil can be frustratingly vague. There’s no easy answer: Based on different environmental and soil conditions, different plants uptake lead at vastly different rates.
In an attempt to shed some light on the subject, Ph.D. student McClintock conducted a series of tests on leafy greens growing in different environments. Chard growing in West Oakland soil with 2,500 ppm of lead showed levels as high as 30 ppm in its leaves, while collard greens in the same soil averaged only 5 ppm. Other tests found that chard growing in beds with 320 ppm took up 3 ppm, and that collards in 215 ppm soil took up almost nothing. And a test in clayey North Oakland soil with lead levels of 700 ppm revealed lead in mustard greens ranging from 1 to 5 ppm. These figures may appear low, but consumption is dangerous in aggregate — particularly for children and when combined with accidental ingestion of contaminated dust during or after gardening.
While there’s no clear rule for determining lead uptake, as a general guideline the further you are from the roots, the less lead will be present. A root crop poses the highest risk, a short leafy green is apt to absorb a moderate amount of lead, and a piece of fruit growing from the branch of a tree (or tomato plant) is unlikely to uptake much lead at all. Peeling or scrubbing produce can help reduce the risk. For the curious, plant-tissue testing is available to the public.
With the right precautions and the right so
il, it can be completely safe to grow vegetables directly in urban East Bay dirt. When Esperanza Pallana decided she wanted to garden in her yard near Lake Merritt, which abuts a gas station, she started with a soil test. The result was a surprisingly low 96 ppm, small by any standard. So she opted to grow directly in the ground, and says she’s now more concerned with particulate matter from nearby freeways.
As a food educator and consultant for many urban gardening projects, and a member of the East Bay Urban Agriculture Alliance, Pallana also advocates for various forms of bioremediation — the easiest and most popular of which is mixing compost with native soil. Not only does this improve soil conditions for growing vegetables, but it also dilutes lead content while binding it in the soil and making it less available to plants and humans. Yet this takes time and energy, and is no magic bullet for urban gardeners eager to plant their first row of lettuce.
The complexity of the issue poses a challenge for the City of Oakland. As it revises its laws around urban agricultural this summer and fall, it bears a responsibility to address soil contamination — even if the push is toward less, not more, intrusion in the lives of urban farmers.
Oakland’s existing zoning regulations around urban agriculture were established in 1965, a time when farming was less welcome in the urban environment. Until two months ago, growing produce for sale at a private residence was not permitted.
Certain activities and zoning classes still require a costly conditional use permit. But the pending revisions, hastened by the uproar surrounding the citing of Novella Carpenter’s Ghost Town Farms for operating without a permit earlier this year, should both clarify the regulations and loosen the reigns.
Erik Angstadt, deputy director of planning and zoning, said that the city is looking to allow as much urban agriculture activity as possible, reducing the need for permits, oversight, and special conditions — as well as related fees. While this may cause urban farmers to rejoice, it also limits the city’s ability to mandate or otherwise oversee soil testing and remediation. “For the small-scale stuff, we’re trying to get away from any sort of permit,” Angstadt said. “The good side is that you’re permitting people to do it, but the bad side is that you’re losing your ability to control it.”
A series of public meetings continuing through October, plus input from various city committees and the Oakland City Council, will fine-tune the planning department’s recommendations. But it’s uncertain at this point how much, if it all, the issue of soil contamination will be addressed beyond a basic educational message directed at the backyard gardener.
The planning department is likely to recommend permits and may propose some regulatory controls for soil testing with large-scale commercial uses, Angstadt said. A community garden on a city-owned lot may still need a conditional use permit, and while soil testing and remediation is not currently required in such cases, it’s possible that will change.
Yet in the rare instance where vegetables are grown on a small residential or non-commercial lot in soil that is toxic and then sold to the public, the city is likely to be powerless. Without a permit, there’s no mechanism for enforcement.
Lead is one of the most common contaminants in the country, particularly in urban areas, and other cities are grappling with the same issues as Oakland. Heather Wooten, a member of the Oakland Food Policy Council and an urban planner who has consulted with cities from coast to coast on urban agriculture policies and zoning, said each jurisdiction has to decide how to deal with soil pollution.”Cities don’t want to incur liability from allowing people to grow, eat, and sell food and possibly getting contamination,” she said. Yet their solutions vary widely.
Chicago’s plan mandates the use of raised beds for all gardens on city-owned land. Baltimore’s is even more strict, requiring community gardeners on both public and private land to file soil testing results and remediation plans. Seattle recommends but doesn’t require soil testing, while San Francisco’s policy, passed in April, allows anything grown on less than an acre, with no controls for soil contamination whatsoever.
Berkeley is hot on Oakland’s heels and may begin addressing urban agriculture as soon as next month. Last October, the Berkeley City Council directed the planning commission to develop a policy allowing home-based businesses to sell garden produce in Berkeley’s residential neighborhoods. The issue will go before the planning commission at a public meeting in September, said staffer Jordan Harrison. The issue of soil contamination has played into discussions to date, but no solutions are forthcoming.
Ultimately, Wooten recommends a flexible approach. “The policy needs to acknowledge that this is an issue, and cue people to pay attention to it,” rather than guiding them down a single path, she said. In addition to playing an active role in education, cities could cover the cost of soil testing for anyone who requests it. Further, they could require testing only on public sites and prioritize public land for community farms.
All this discussion of city governments mandating soil tests leaves City Slicker Farms’ Barbara Finnin a bit uneasy. She’d rather not discourage anyone from embracing urban farming, and fears that excessive regulations would do just that. “I don’t want to have a huge scare thing where nobody is growing food,” she said. “When it gets into mandating things, that gets into fees and all these kinds of things” — costs that her organization’s clients in West Oakland probably can’t afford.
“We really want to be safe, but how do we do it so that we’re not putting up barriers?” In a perfect world, she said, all urban gardeners would follow best practices around testing and remediation without city oversight, ideally supported by a streamlined and accessible facility providing free testing to residents.
Alameda County already offers free soil testing and remediation grants in conjunction with a home consultation. The University of Massachusetts, meanwhile, provides low-cost soil testing for $10 and up, a service that many East Bay urban farmers have taken advantage of, including City Slicker Farms and the 39th Street neighbors. It’s likely the nation’s cheapest mail-away test, and, according to interim director Tracy Allen, processed 18,000 samples last year — nearly double its figure from a decade ago. Every time the economy takes a dip, she said, soil tests take off.
No matter how Oakland and Berkeley approach their new regulations, carting away contaminated soil to a hazardous waste dump doesn’t appear to be a viable option. That’s why the proponents of the Community Crossroads Garden are so miffed that that’s the solution they were offered. Beyond being costly and impractical, it merely moves the problem somewhere else. The same is true when using plants like sunflowers and bamboo to absorb lead and other heavy metals, which must be similarly disposed of. But there’s another large-scale solution that may hold serious promise.
In June, Steve Calanog of the EPA began demonstrating a treatment in West Oakland’s South Prescott neighborhood that uses ground-up fish bones to bind lead in soil and create stable compounds that are harmless to humans. Once mixed with the soil, decomposing bone fragments deposit phosphates that move through the soil and encapsulate tiny particles of lead. A six-inch layer of clean soil is poured over the top, leaving the dirt safe to plant in. An entire yard can be remedied with one treatment, which takes a few weeks to run its course. The EPA’s two-year project here marks the first time that the approach, already proven at military and mine sites over the last 15 years, is being employed in a residential setting.
The need for a full arsenal of solutions will only grow as demand for urban farmland increases, whether it’s in backyards, abandoned lots, or city parks. While the 39th Street neighbors don’t currently have plans to resurrect their garden, another neighborhood organization is looking to site a smaller garden at one of two local parks, including one just a couple blocks away.
Myriad organizations geared toward food justice and urban farming are based in Oakland alone: Ghost Town Farms, City Slicker Farms, East Bay Urban Agriculture Alliance, Oakland Food Policy Council, Institute of Urban Homesteading, Phat Beets Produce, People’s Grocery, Oakland Based Urban Gardens, and Bay Localize, to name a few.
In Berkeley, groups like the Berkeley Community Gardening Collective and Urban Adamah are preaching the same gospel. Yet there’s only so much land to go around, and most of it requires some level of remediation — or avoidance.
In the end, the soil contamination issue comes down to that: Fix it with compost, fish bones, or other bioremediation methods, or leave it well enough alone by mulching and planting vegetables in a raised bed. In the middle of a city, gardeners still have to deal with the daily deposition of heavy metals through particulate matter in the air — so washing before eating remains imperative.
No matter what urban farmers have to do to get it, they’re better off enjoying their own fruits and vegetables than those bought at a grocery store, said Rudy Blume, founder of the Oakland-based Institute of Urban Homesteading and coauthor of the book Urban Homesteading. In fact, she said, she can hardly believe that people are so worried about lead contamination when, elsewhere, farmers are spraying their crops with pesticides and herbicides. “I just feel like the food that I grow in my yard is going to be so much healthier than conventional agriculture,” she said.
And she has a point. But you know what they say about an ounce of prevention.