Dynamic Soil Testing for Safe Urban Food Production

                                                                   © 2012  by Maren Leyla Cooke, updated May 2015

 

Urban farming

Pittsburgh is now home to a vibrant and growing urban farming movement.  It's one part of a hopeful trend in which Pittsburghers are helping to empower young people, restore local economies, rebuild communities, reduce crime, protect the environment, improve public health, and enhance local food security.  Our city is particularly well positioned for this development, with a vast stock of unused land (more than 14,000 vacant lots plus additional land in private hands), people needing employment, youth from all walks of life looking for constructive things to do, and countless citizens strongly motivated for positive change.  Amazingly, urban farming programs can address all of these issues simultaneously.

Local food security 

Agriculture is the number-one industry in Pennsylvania, but we grow mainly for export -- while importing most of our food from elsewhere.  In an age of increasing concern about both energy and security, this approach is clearly unsustainable.  Food consumed in this country travels an average of 1500 miles from farm to table, at great cost in terms of fuel use, emission of climate-changing carbon dioxide and other pollutants, and quality of the food.  Moreover, monocultures on big industrial farms are ripe for crop failures, and large centralized systems for food production and distribution present a significant risk for contamination or interruption -- either accidentally (think beef, spinach, and green onions) or intentionally.  We need to begin producing more of our food in our region, and that includes rural, suburban, and urban farms and gardens.  And to do that, we need to both keep the remaining farms in business and nurture a new generation of food producers.  With the average age of Pennsylvania farmers approaching 60, there is cause for concern -- as well as great opportunity for today's youth.

Consumer choices can help sustain regional farms, through farmers' markets and subscriptions to community-supported agriculture (CSA) farms, and by demanding local foods in area stores.  But there are many consumers without such choices -- in some low-income areas of the city, there aren't even any grocery stores;  such regions are called "food deserts."  This is another side of food security -- the secure ability of every segment of the population to obtain healthy, affordable food.

Empowering youth 

Many young people in our urban core face uncertain futures.  Numerous programs are in place attempting to address this issue, but there are few activities that can be as fun, educational, motivational, and rewarding as growing food.  And while kids are having fun and being physically active outdoors, they're also learning about nature, health, nutrition, and good citizenship.  And they're gaining leadership skills and learning practical crafts that will open up job opportunities in fields like agriculture, horticulture, landscaping, building, and business.  Perhaps even more significantly, as at-risk youth in underserved communities take part in producing food for their families and neighbors, they gain a sense of ownership and responsibility that they may have lacked before.

Revitalizing neighborhoods

Pride of place is not limited to the people participating directly in the projects.  A piece of land that is obviously cared for is much less of a target for litter, dumping, and crime.  It has been observed again and again that urban farms and community gardens increase real estate values for the surrounding properties, and can bring neighborhoods together.  Add to these effects the generation of local jobs, more young people engaged in creative enterprises, increased access to fresh food, and beautiful and functional landscapes, and it's a winning combination.

Local economies

Whether or not large corporations see fit to locate stores in low-income neighborhoods, residents can begin taking control 

of their economic and nutritional destiny.  Creating the means of food production within our urban core is a great first step.  Pittsburghers can keep food dollars in their local communities by starting businesses that grow and sell food right in the neighborhood where it's grown.  This will create jobs for youth growing food, as well as fostering business skills and generating additional opportunities through value-added products.  Individual families can also become part of this urban renaissance, as residents who are generations removed from gardening and preserving foods will be able to participate in workshops and classes to learn those skills.  Those lacking outdoor space, or with unsafe soil, will be able to join community gardens.  Right now, there are people gardening where it's unsafe, and others not gardening at all.

Urban soils

Although urban land has tremendous potential for growing food crops, it is essential to go about it with care.  The history of any piece of land affects its present and its future;  in many places there may be residual contamination from past land use (known or unknown).  One of the most common contaminants of known concern is lead.  While Pittsburgh's public health pioneer Dr. Herbert Needleman was still at Harvard, he began investigating the link between childhood lead exposure, learning deficits, and behavioral problems.  With persistent research and advocacy, progress was made on the public policy front, but it took years;  lead paint was not banned until 1978, and lead was not completely phased out of gasoline until 1996.  Thus, soils near busy streets or painted houses is always suspect.  And Pittsburgh, a hub of steel production and coal-fired energy generation, has regional residues as well.

Subtle sources

Urban soils may also be contaminated by illegal dumping, application of pesticides or herbicides, or industrial emissions into the air, water, or soil -- whether they are long past (and perhaps invisible) or ongoing.  In addition, because of Pittsburgh's hilly topography many sites have had fill material brought in from elsewhere, or soil moved from one place to another on the property.  Whenever and wherever they came from, toxic heavy metals and organic pollutants can be taken up through plant roots or splashed onto plants from the ground below.  In order to turn some of Pittsburgh's vacant land from a liability into an asset, we first have to make sure each site being considered for farming, gardening, or play is safe.

Vulnerability of young people

It is well-established that children are far more susceptible to the adverse affects of environmental contamination than adults:  their bodies are still developing, with critical phases of nervous system and reproductive system development continuing into the teen years.  They also spend more time outside, and are generally more active than adults -- their more-rapid respiration takes in pollutants from today's industry and transportation, but also dust kicked up from the ground on a dry day.  And especially for younger children, hands often find their way into mouths.  Is the answer to keep kids away from soil?  Hardly;  a much better solution is to make sure the dirt on their hands is safe.

Soil testing

It is clear that soils need to be tested prior to any food-growing enterprise, both for the safety of the food itself and for the health of the people working the land, especially young people.  However, the distribution of contaminants is often highly uneven, with variations related to former buildings, roads, and dumping.  Furthermore, soils have often been moved around due to redevelopment, construction, and landscaping over the years, and one can neither discount the potential of land near roads nor trust that land away from them will be safe.  Hence, soil testing needs to be systematic and detailed for each site.

New technology

Conventional soil testing at a state laboratory requires charting a grid, clearing the surface, digging samples (usually just a few), preparing and packaging them, shipping them off and waiting weeks for results, not knowing how optimal the grid placement was relative to often-uneven distribution of contaminants, nor how many samples are warranted.  Now, however, there's a hand-held instrument that uses X-ray fluorescence spectrometry (XRF) which is designed for soils, and which is safer than the similar devices often used for lead paint testing because it uses a battery-powered X-ray tube instead of a decaying radioisotope as an X-ray source.  This unit allows for dynamic selection of sample locations and on-the-spot analysis for dozens of elements at a time (conventional lab tests would cost ~$10-40 each for just a few heavy metals, and a grid sample could be three feet away from where a car battery sat for twenty years).  It can be linked to a GPS transceiver to further streamline site mapping, and can even detect contaminants in plant tissues.  And while the XRF is not solely oriented toward nutrient testing like the basic state lab tests, several key nutrients are detected including phosphorus and potassium. (Nitrogen, the third macronutrient, is volatile and moves through soil freely, so generally needs to be renewed each season anyway.)

Research
This program could produce substantive research results while providing for some of the real needs of real people.  How effectively certain crops are affected by and can remediate contaminated soil -- the rate of remediation for different contaminants and different crops, and in what plant tissues the elements are sequestered;  the impact of various contaminants on plant growth and food safety;  the results of different land-use histories;  and how contaminants move through soil under different conditions are among the many important questions that can be addressed.

Funding needs

The major obstacle to this enterprise is the cost of the XRF device, upwards of $30,000 (including a nonprofit discount);  additional initial expenses would include the device-linked GPS unit, software, and training.  The XRF instruments can be rented (typically ~$600/day for short periods, often plus several hundred for an operator), but we propose to get a unit into the hands of the local nonprofit community so that testing can take place as needed without trying to coordinate people, instrument availability, and weather -- and then being unable to go back and check more samples.  Because of the extensive skill-set required for the XRF operation and data analysis, it is far more cost-effective to bring the equipment into the community than to hire the service each time it is needed.  Since the ultimate goal of this work is to strengthen our community by working with urban youth, building local economies, and creating a sustainable local food system, we are hoping that the foundation community will be able to help with startup costs.  We had an initial contribution from the Allegheny County Health Department for a small demonstration project, and hope to gather additional funds to begin a soil testing program in earnest.

Financial plans

Several models are possible for this program.  It could be an arm of a nonprofit organization, or a social enterprise.  In the latter case, once we can secure funding for the instrumentation, software, and training we would operate on a fee-for-service basis, at rates intended to make the service accessible to everyone (perhaps with a sliding scale based organizational size or individual income, and/or different levels of service).  In either case, we'll be able to provide testing and analysis for farming projects, community gardens, school gardens, homeowners, and soil remediation projects -- more quickly, at substantially less cost, and with far more detailed results than other approaches.  Using the XRF results, spatial data from the GPS and logged sample depth, and geographical information system (GIS) software we will be able to produce maps of soil contamination, and can couple these with recommendations for mitigation and cultivation.

To discuss this project, please email Maren:  maren dot cooke at gmail dot com