Brownfields and Gardening - Does this mesh? Brownfields in the U.S.

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1 Brownfields and Gardening - Does this mesh? Dr. Sabine E. Martin, P.G. Kansas State University Florida Brownfields Conference November 2010 Brownfields in the U.S. Estimated 450,000 to 1 Million sites 5 million acres of abandoned industrial sites in U.S. cities roughly the same amount of land occupied by 60 of the largest U.S. cities U.S. Department of Housing and Urban Development 1

2 Small Scale Food Production Trends 6.8% increase in farmers markets between 2006 and 2008 (USDA) More than 18,000 community gardens in the U.S. and Canada (ACGA) In 2008, there were appr. 4,600 farmers markets in the U.S. (USDA) 2

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4 From Brownfields to Gardens What are the Benefits? Aesthetics Mitigate blight and improve community image Preserve neighborhoods Serve as community gathering places Locally grown foods From Brownfields to Gardens What are the Benefits cont. Address food deserts Physical activity Economic benefits Address and mitigate public health and safety concerns Improve and protect the environment 4

5 Washington Wheatley Kansas City, MO Contaminants: Former Residential Lots Asbestos: from insulation, carcinogen Lead from use of lead based paint Metals from coal ashes PCBs: from leaking transformers Pesticides (DDT/DDE, chlordane, arsenic) PAHs: polycyclic aromatic hydrocarbons, from incomplete burning of coal and other organic materials, low solubility, persistent in soil and water, adsorbed by organic matter 5

6 Abandoned Service Station 6

7 Associated Contaminants Service Stations Benzene: ene carcinogen, volatile Ethylbenzene: possible human carcinogen, volatile to semi-volatile Waste oil: As, Cd, Hg Dry Cleaners 7

8 Associated Contaminants Dry Cleaners Chlorinated Solvents PCE/Tetrachloethylene/PERC: volatile, reasonably anticipated to be a carcinogen TCE: Trichloroethylene, probable carcinogen, less volatile than PCE, persistent in soil and water 8

9 Before acquiring an urban vacant lot to garden Need to know history of site/lot to find out re potential ti contamination ti Phase I environmental site assessment Title/Records Search Talk to neighbors Visual reconnaissance Sampling, if warranted (Phase II ESA) (EPA, TBA (states/epa); consulting firms) 9

10 ph Agronomic Information Organic Matter Nutrient Status: Nitrogen, Phosphorus, Potassium, and other macro- as well as micronutrient concentrations Commercial labs, USDA Cooperative Extension System (universities) Most Common Contaminant in Urban Environment Lead Lead based paint, automobile exhaust, waste oil Lead levels of mg/kg are common in urban soils 10

11 Potential Exposure Pathways Direct exposure (Ingestion, Inhalation) Soil Human Indirect Exposure Soil Plant Human Ways to minimize Human Exposure to Lead in Soils 1. Watch your toddlers! 2. Wash your hands 3. Root vegetables should be washed and peeled before consumption 4. All other vegetables should be thoroughly washed prior to consumption 5. Apply soil amendments to reduce risk 11

12 Our Project Work with select community based gardening initiatives to evaluate uptake of heavy metals and other contaminants by food crops, and develop recommendations for seedbed preparation and corrective/protective actions to address contaminants. Establish site history Process Collect soil samples Best management practices (adding soil amendments, raised beds) Continuous monitoring, soil and produce sampling Training and technical assistance to participating organizations (sample collection, site eval., etc.) throughout 12

13 Washington Wheatley Kansas City, MO Washington Wheatley Kansas City, MO 13

14 Washington Wheatley Kansas City, MO Soil Test Results Detectable levels of DDT (0.04 ppm to1.3 ppm) and DDE (0.03ppm and 0.04 ppm) DDE is a daughter/breakdown product of DDT DDT, an insecticide, was banned in the US in 1972, but is very persistent in soils (half-life of DDT ~15 yrs., DDE ~11 yrs.) No detectable chlordane Mildly elevated lead levels (58mg/kg-305mg/kg) Distribution of lead was highly heterogeneous Laboratory results were in close agreement with in situ XRF data 14

15 Recommendations, 2009 To minimize absorption of lead and/or DDT by plants: Maintain soil ph levels above 6.5 to 7.0. Lead is relatively unavailable to plants when the soil ph is above this level. The soil ph at the WW site is about 7; therefore, no action is required. Lead is also less available when soil phosphorus concentrations are high. Phosphorous concentrations at the WW site are very high. So phosphorus addition will not be necessary for this growing season. Add organic matter to soil to reduce both lead and DDT availability t l t to plants. Summer 2009 Kansas City Test Plot Experimental Design: Completely randomized block design (RCBD) in spilt-plot arrangement Factor Compost Plant type Variables yes (28 kg/m 2 ), no tomato, sweet potato, swiss chard 15

16 Washington Wheatley Test Plot (2009) Pb Concentrations in Tomato Main Plot Treatment Cleaning Method Pb Uptake in Crop Tissue (mg/kg)* Compost Kitchen ± Lab ± Total Pb in Soil (mg/kg) 97 No Compost Kitchen Lab 0.075± ± *Dry weight All concentrations are averages of three field replicates; 2009 data Compost addition did not reduce Pb concentrations in tomatoes. Concentrations are far below the recommended maximum permissible concentration (FAO/WHO, 2009) of 6 mg/kg dry weight. 16

17 Pb Concentrations in Sweet Potato Main Plot Treatment Compost No Compost *Dry weight Cleaning Method Kitchen Lab peeled Kitchen Lab peeled Pb Uptake in Crop Tissue (mg/kg)* g) 0.752± ± ± ± ± ± All concentrations are averages of three field replicates; 2009 data Total Pb in Soil (mg/kg) Compost addition did not reduce Pb concentrations in sweet potatoes. Concentrations are far below the recommended maximum permissible concentration (FAO/WHO, 2009) of 1.5 mg/kg dry weight. Pb Concentrations in Swiss Chard Main Plot Treatment Compost Cleaning Method Kitchen Lab Pb Uptake in Crop Tissue (mg/kg)* g) ± ± Total Pb in Soil (mg/kg) 81 No Compost Kitchen Lab ± ± *Dry weight All concentrations are averages of three field replicates; 2009 data Compost addition reduced Pb concentrations in swiss chard ~37 to 42% compared to the treatments without compost. Concentrations are far below the recommended maximum permissible concentration (FAO/WHO, 2009) of 6 mg/kg dry weight. 17

18 Kansas City, Test Plot Washington Wheatley Kansas City, MO Compost Crop Type Total Pb in Soil (mg/kg) Pb Uptake in Crop Tissue (mg/kg)* YES Swiss Chard Carrot NO Swiss Chard Carrot *Dry weight All concentrations are averages of four field replicates; 2010 data Concentrations are far below the recommended maximum permissible concentration (FAO/WHO, 2009) of 6 mg/kg dry weight for swiss chard. The recommended MCL for carrots is 1.5mg/kg. 18

19 Swiss Chard Pb versus available P in Soils 1000 iss Chard Pb (µg/kg) Sw Mehlich-3 extractable P (mg/kg) Lead Reduction through Compost Addition Plot # Total Pb (mg/kg) Prior to Compost Addition After Compost Addition Average total Pb

20 Regulatory Limits for Garden Soils??? Recommended Lead Levels The EPA's standard for lead in bare soil in play areas is 400 ppm by weight and 1200 ppm for non-play areas. This regulation applies to cleanup projects using federal funds. 20

21 Dealing with a mildly contaminated Site Raised Beds, covered paths Disadvantages: Loose space Bring in new soil, $$ Dealing with a mildly contaminated Site Grow in Bags Disadvantages: Loose space Bring in new soil, $$ 21

22 Dealing with a mildly contaminated Site Grow in-situ Disadvantages: May need to take some precautions Add amendments Resources TBAs (States) TBAs (EPA) EPA grants Consultants Commercial labs USDA Cooperative Extension System (universities) K-State 22

23 Contact Information Dr. Sabine Martin Kansas State University Dr. Ganga Hettiarachchi Dept. of Agronomy Kansas State University