Frequent Questions about Brownfields and Urban Agriculture
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- What is Urban Agriculture?
It is defined in different ways by different organizations.
The North American Urban Agriculture Committee defines it as:
"The production, distribution and marketing [and disposal] of food and other products within the cores and edges of metropolitan areas. Urban agriculture is a complex activity, addressing issues of food security, neighborhood development, environmental sustainability, land use planning, agricultural and food systems, farmland preservation, and other concerns."
The USDA National Agricultural Library notes:
"Around 15% of the world's food is now grown in urban areas. City and suburban agriculture take the form of backyard, roof-top and balcony gardening, community gardening in vacant lots and parks, roadside urban fringe agriculture and livestock grazing in open space."
For the purposes of this website within the context of EPA's Brownfields and land revitalization program, urban agriculture can include public, community and private community gardens as well as larger scale urban farms or orchards as well as growing herbs, spices, flowers for market, raising chickens or livestock, and keeping bees. Urban agriculture may also include growing crops for animal feed or bedding, as well as non-food crops for landscaping, flower gardens, seed, bulb or plant sale, oil, fragrance, dye, biofuel and fiber.
Particular concerns regarding soil contaminants and exposure risks that present issues for in-ground gardens and farms may be avoided where hydroponic, roof-top gardens or farms or vegetated walls or other structures using controlled growing medium and limited soil contact.
- Who is engaged in Urban Agriculture?
Many different organizations with varying skill sets organize and manage gardens or urban farms. In some communities, this may be a volunteer-led effort linked to the food bank, focused on community gardens. In others, experienced community organizations or City Park Departments operate gardens or farms. In addition, many private property owners and public organizations seek to reclaim urban (suburban and rural) lands for food production or other agricultural purposes.
Local extension agents and certified Master Gardeners may be of particular assistance in providing technical assistance in understanding soils, nutrients, and plant selection and plant growth needs. State and tribal programs maintain property inventories and local government environmental professionals may be of assistance in selecting appropriate properties and determining the presences of environmental contaminants, where needed.
- How do you start a community garden?
Your local extension and local garden organizations may be able to provide information on starting a community garden in your area. Information about County Extension locations and their services can be found at USDA National Institute of Food and Agriculture (NIFA) website.
The American Community Gardening Association website provides a range of tools that can help you establish a community garden on their website. Community support, interest and commitment are critical factors to organizing a successful community garden.
EPA, in addition, suggests you consider the property history as it may indicate contamination.
- Are all vacant lots brownfields?
No, not all vacant lots are brownfields although many may be.
A Brownfield is defined as:
"a property, the expansion, redevelopment, or reuse of which may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant."
Small Business Liability Relief and Brownfields Revitalization Act
Common examples include abandoned gas stations, scrap yards, areas where older structures have been demolished unsafely, former industrial manufacturing industry, strip malls with dry cleaners, warehouses, mine scarred lands, as well as areas of former illegal dumping and other industry operations.
- Can a Brownfields assessment grant pay for the necessary testing to determine the contents of the soil?
Yes! A Brownfields assessment grant can pay for community wide and property-specific history reviews to indicate likely contamination and property-specific soil and groundwater testing needs. An assessment grant provides funding for a grant recipient to inventory, characterize, assess, and conduct planning for cleanup for a site. An assessment grant may pay for other types of soil tests (pH, organic content or other tests) as they relate to the assessment of environmental contaminant risks or their safe management but this may need to be decided on a case by case basis in consultation with your Brownfields project manager.
Other testing for healthy plant growth – organics, nitrogen, phosphorus and potassium or NPK – and other agronomic parameters – may be available from your extension office or the land grant university in your state. Learn more about land grant universities.
- Can a Brownfields multipurpose grant be used to assess and clean a property proposed for a community garden or urban farm?
Yes, it may be able to be used if it meets other eligibility criteria! Please go to the Brownfields Grants page for more information.
- Why should I test for environmental contaminants?
You may want to test for environmental contaminants to understand the proposed property and your options for managing it after identifying potential risks from environmental contaminants to public health and the environment or lack of risks. Testing information may also help reassure community members, gardeners or others that produce is safe to consume or use.
- What contaminants should I test for at my site?
The types of contaminants you are likely to find depend on the history and use of the property.
As a general rule at Brownfields, environmental professionals look at the property history and use to identify what environmental contaminants may be present and require further testing.
You can do a similar search in your community. A librarian at your local public library may be able to help you locate historical property records, fire insurance maps and city directories that identify previous property uses, or you may be able to find information on the internet.
Sometimes looking at a property can provide visual cues to potential contamination. Soil staining, an oily sheen on puddles, visible tanks or piping, or piles of debris may suggest petroleum tanks or illegal dumping.
Our extensive manufacture and use of lead in gasoline, paint, batteries, and other consumer products such as building materials and historical pesticides, make it a common first contaminant to consider for testing. In some areas, naturally occurring higher levels of arsenic may also be of concern. In addition, areas of historical power generation or industrial activity may suggest other contaminants to consider for testing, like combustion byproducts, waste ash, fuels, hydrocarbons stored or used to power machinery, solvents, degreasers for cleaning equipment or other hazards. If you suspect environmental contaminants, talk with your local officials and they may be able to help you select a safe site. The following publications, though not exhaustive, provide some common examples of contaminants related to certain kinds of product or industry.
For more information about soil contaminants related to gardening, check out
- Soil Contaminants and Best Practices for Healthy Gardens (PDF)
- Sources and Impacts of Contaminants in Soils (PDF)
For more information about soil testing, check out:
Environmental contaminants, if found, may be present at low levels that pose no risk. Also, they may pose no threat to your food - many plants do not take up contaminants or only in small amounts that pose limited risks.
We recommend testing because we want to make sure that all gardeners, especially children, are not at risk from unsuspected contamination at levels that do pose risks.
- What can I do personally to avoid exposure to soil contaminants?
People generally come in contact with soil contaminants through skin contact, breathing in dust or soil particles, and accidentally eating (or drinking) small amounts from unclean hands or food, drink or cigarettes picked up for eating, drinking or smoking during or after gardening without washing their hands.
Wearing gloves is essential when handling the soil because soil may contain pieces of glass, nails and other dangerous items as well as other contaminants. Consider whether you should get a tetanus shot to protect yourself from tetanus if you believe rusty nails or other onsite debris may be onsite. Wearing a hat, long pants and long sleeves or covered shoes on the site can provide protection from sun, mosquitoes or other insects as well as poison ivy or other plant irritants.
If you clean the soil or bring in clean material for cover, you can reduce surface exposure and reduce the chance of contaminated surface soils runoff into the stormwater systems.
While covering soils that have not been cleaned tested with hard or soft scapes or geo textiles is an option to remove potential exposures, EPA or our State and tribal colleagues may encourage assessment first to better understand the property.
Where appropriate (soil contaminant levels are not so high as to pose health or environmental risks), adding soil amendments from certified soil sources can reduce the exposure to soil contaminants, bind contaminants or may even add bio organisms that can degrade or break certain contaminants down. Adding organic material and soil amendments can improve the ability of soil to hold water too and also allow water to penetrate the soil, reducing storm water runoff.
- What is pH?
The pH scale measures how acidic or basic a substance is. The scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic, and a pH greater than 7 is basic. For more information on soil pH, check out the University of Minnesota's Modifying Soil pH Web page. EPA's Acid Rain website has a useful description of pH.
- Why is pH an important issue in soils at Brownfields?
The pH of a soil can affect what form of a contaminant you may find and whether that contaminant moves in the soil or binds tightly to soil particles or added organic material. If bound tightly to particles, it may be more difficult for the plant to take it up into the roots. In general, many plants prefer a pH from 6.5 to 7 and changing the pH to near neutral can also reduce the likelihood of contaminant movement or plant uptake in many, though not all cases.
- What is bioavailability?
The bioavailability of a contaminant is the capacity to "cause a direct effect on plants, animals, and humans because it can be taken up by their bodies." The bioavailability of a contaminant depends on characteristics of the site and the soil. The site conditions affect how tightly the contaminant is held by soil particles and the solubility. If solubility is high, then the contaminant is more bioavailable and also more likely to leach out of the soil. Soil tests measure the total or chemically extractible amounts of contaminants. However, the bioavailable portion may be much less than the total. Bioavailability varies over time, especially if there is a change in the pH or organic matter content. Learn more at the relationship of bioavailability and soil contaminants at EPA's Assessing Relative Bioavailability in Soil at Superfund Sites Web page.
- What is phytoremediation?
Phytoremediation is the use of green plants to clean soils. It can be specific plants alone or in combination with soil amendments and other additions to uptake and extract certain metals (NOT LEAD), pesticides, solvents, explosives, crude oil, polycyclic aromatic hydrocarbons, and landfill leachates from contaminated soil and reduce these from the vegetation. As an engineered system, there has been a lot of research to determine which, if any, contaminants plants can remove from the soil and under what soil conditions. Learn more about phytoremediation research from USDA and phytotechnologies and training by the ITRC and the EPA Clean Up website.
- Does phytoremediation work on lead?
No. Close to forty years of research on the use of phytoremediation to remove lead suggests it has limited value. Research has shown that lead in soil, rather than uptake by plants, is the primary source of concern particularly to those at high risk, such as children who may be exposed to lead in soils. Therefore, neither the phytoremediation plants nor garden produce are likely to take up lead if present in soil.
For more information about phytoremediation, please see The Citizen’s Guide to Phytoremediation.
- What are soil amendments?
Soil amendments are materials added to the soil to improve soil structure and plant growth as well as to clean environmental contaminants, where needed. The addition of soil amendments can reduce or remove potential exposures to contaminants, including lead in soil, to children and others and can benefit plants and the environment. Compost, soil amendments, or clean fill from certified soil sources can be used to help bind lead and make it unavailable for exposure through contact with the soil. For more information about soil amendments for agriculture, go to the National Sustainable Agriculture information service page on soils and compost.
- What are the options for growing above-ground, if we are worried about planting in the ground?
There are a number of alternative methods that do not involve growing plants directly in the soil.
Some alternative technologies include raised beds, hydroponic or aquaponic systems, and vertical or container based gardening systems. Greenhouses can be used instead to provide clean soil and a safer environment for plants to grow. Additionally, if growing foods is not possible in or near the contaminated soil, growing non-food crops may be an option or making the land available to sell foods is another option. Cleaning or capping the sites to locate a farmer's market, supermarket or other food retail can still provide healthy affordable food in your community.