Urban Gardens on Brownfields: Making Them Safe

Brownfields 2011 Philadelphia, PA – April 5, 2011 Vanessa Steigerwald-Dick, Ohio EPA Amy Yersavich, Ohio EPA 1

What is Urban Agriculture or Urban Gardening?

 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.

(as defined by the North American Urban Agriculture Committee) 2

Who is doing this farming in Urban Areas?

 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.

(from U.S.EPA’s Urban Ag Website http://epa.gov/brownfields/urbanag/ ) 3

Why on Brownfields?

 Because much of the vacant land in urban areas meets the definition of a brownfield, be it historically industrial, commercial or residential land.

 Although urban residential areas, that have always been residential, may not seem like brownfields, they can be due to historic ubiquitous contamination found in cities with a history of industrial use… 4

Urban Gardens – How Clean is Clean?

Traditional state brownfield cleanup programs, including the Ohio’s Voluntary Action Program (VAP), have not developed cleanup standards that take into account what levels of soil contaminants are safe for contact with the soil and for eating the fruits and vegetables grown on an urban brownfield.

Urban garden in Cleveland, Ohio which practices both container and in-ground gardening Given the recent development of urban gardens, most regulatory cleanup programs are less familiar with the human activity patterns, and hence human exposure assumptions to use at these sites.

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Chemicals of Concern (COCs) in Urban Gardens

 Primary Contaminants of Concern:  Metals (lead and arsenic)  Polycyclic Aromatic Hydrocarbons (PAHs/PNAs)  Secondary Potential Contaminants of Concern :  Volatile Organic Compounds (VOCs)  Polychlorinated Biphenyls (PCBs)  Other Metals, Herbicides, Pesticides, Dioxins, and other Semivolatile Organic Compounds  Site specific 6

Urban Agriculture State of Knowledge

   MOST plants in MOST situations appear to have limited uptake of contaminants…but this is difficult to quantify and additional research is needed to better evaluate plant uptake and resulting ingestion of contaminants in fruits and vegetables Surface contamination of plants Bioavailability of metals   May go down over time in a NORMAL garden Can be further reduced with soil amendments

What about the exposure risk from working in these gardens then??......

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Urban Gardens- Recent Practices

 Sample the soils and compare them to direct-contact soil standards for residential properties which take into account incidental ingestion, dermal contact, and inhalation of particulates and volatiles.

 Most residential standards assume children and adults are on the property up to 350 days a year for 30 years.

 Upside - residential soil cleanup standards are generally very protective for urban gardening. Downside – can rule out many good urban sites that might also be protective.

 Note: Direct-contact soil standards do not address ingestion of plants in urban gardens.

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Common Human Health Direct Contact Soil Exposure Scenarios

U.S. EPA Regional Screening Levels & State Programs Residential Land Use  Children and adults living at residence   350 days per year 30 years Commercial and Industrial Land Use  Adult workers   250 days per year 25 years Excavation and Construction Workers  1 year or less, property-specific risk assessment Recreational Land Use/Greenspace  Property-specific risk assessment 9

We have some recreational risk assessment examples:

   Neighborhood parks and playgrounds have high potential for frequent exposures to children and adults, therefore exposure assumptions very similar to residential Nature preserves and wildlife areas generally have less frequent exposures to children and adults, therefore exposure assumptions often include reduced number of days per year (e.g. 90 or 120 days per year) So what exposure assumptions could potentially be modified for urban ag exposure scenarios?

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What are some potential exposure assumption considerations for urban agriculture?

    Urban agriculture may include:   Community gardens Market gardens Exposure factors to consider:  Days per year: April/May – Sept./Oct., + lower frequency other months of year?

 Number of years?

Point of compliance?

 Depth of soil to assess?

Bioavailability for plant uptake?

 Data to support this?

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Common chemicals of concern and potential risk assessment results

    If you reduce number of days per year (e.g. 90, 120, 150, 175 200, 250 days per year), some chemicals still exceed risk goals (1 in 100,000 cancer risk goal, hazard index 1) Arsenic – background concentrations need to be considered Lead – biokinetic uptake model Carcinogenic PAHs 12

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Combination of Risk Assessment and Risk Management Considerations

Applying current human health risk assessment practices, limited number of exposure assumptions that can be defensibly modified  Will generally increase standards by less than an order of magnitude, usually only 2-4 times If likely that risk-based levels will be exceeded, consider risk management options that may include:     Cover with clay and “clean” soil Remove localized “hot spots” Raised beds with “clean” soil Mulched garden paths 13

Risk Management Options for Urban Gardens

Vertical/Hydroponic Gardens - Toledo Raised Beds - Cleveland 14

Risk Management Options for Urban Gardens

Soil Amendments Garden Soxx - Toledo 15

Re-Imagining Cleveland Project

 Reviewed Proposed Projects  Prioritized Sites  Visited the Sites  Looked for “red flags”  Reviewed Historical Data   Sanborn maps Aerial Photos  All Sites Sampled For:     Metals Polycyclic Aromatic Hydrocarbons (PAHs) Asbestos Volatile Organic Compounds (VOCs)  Sites With Transformers Sampled For:  PCBs 16

Re-Imagining Cleveland Project Sampling Results

 Metals     Mostly Lead and Arsenic 100% of sites exceeded Ohio’s Voluntary Action Program (VAP) Residential Land Use soil standards 45% sites exceeded VAP Commercial/Industrial Land Use soil standards Problem: Arsenic standards for residential land use are often lower than soil background concentrations; therefore obtain/use nearby background data  Polyaromatic Hydrocarbons (PAHs)    75% of sites exceeded VAP Residential Land Use soil standards 33% of sites exceeded VAP Commercial/Industrial Land Use soil standards Problem: What are potential sources of PAHs?  No Absetos, PCBs, or VOCs 17

Cleveland Area Background Study Results Compounds Arsenic Barium Cadmium Chromium Lead Selenium Silver Mercury

Background Upper Limits, mg/kg

0-2' 2-4' 0-4' 21.55

54.15

0.97

21.59

65.58

1.06

20.73

59.27

1.01

20.74

21.17

21.0

21.08

26.8

24.0

Due to no. of censored data these compounds could not be reliably evaluated 0.06

0.08

0.06

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What’s Next: Food For Thought

What risk assessment scenarios are appropriate for urban gardening? Residential? Commercial or Market Gardens - Property-Specific?

 What exposure pathways need to be considered? Soil direct contact, and what about ingestion of food crops?

 Are there different types of human use activity patterns for neighborhood community gardens versus market gardens?  How do we address naturally occuring background concentrations of metals (Ohio’s voluntary cleanup program or VAP Background Workgroup)?

 Can soil amendments reduce bioavailability? If so, by how much? What additional research is needed in the field? In addition to metals, what about PAHs?

 Are raised beds the answer? Where is that soil coming from? Should there be standards for raised bed construction? Should the soil be tested before it’s used?

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Vanessa Steigerwald Dick, Ph.D.

Environmental Scientist Ohio EPA Northeast District Office 2110 East Aurora Road Twinsburg, OH 44087 TEL: 330-963-1219 [email protected]

Amy Yersavich Manager Ohio EPA - Site Assistance and Brownfield Revitalization 50 West Town Street, Suite 700 Columbus, Ohio 43216-1049 [email protected]

Questions?

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