The presentation discusses the high levels of lead contamination in urban soils, particularly in NYC, and explores potential solutions for remediation and carbon sequestration. It highlights the creation of the NYC Clean Soil Bank, which provides safe soil mixtures for community gardening and emphasizes the importance of community partnerships in addressing soil contamination and promoting environmental justice. Key concepts include soil carbon sequestration processes and the use of compost to improve soil health while minimizing exposure risks.

1. Constructing Soil:
The Key Element
for Sequestering
Lead and Carbon
6th National Cultivating Community
Composting Forum
Sara Perl Egendorf
May 13, 2019

2. Presentation Outline:
• Lead (Pb) in Urban Soil
• What can we do about it?
• Carbon (C) Sequestration
• What is it? How does it work?
• Constructing Soil in NYC
• Carbon Sponge + JUST SOIL
• Legacy Lead
• Connecting Across Time and Space

3. Problem: Urban Soils are Highly
Contaminated with Lead (Pb)
- ~36% of NYC’s surface is covered with soil
- No systematic map of NYC soil Pb has been
created, but Pb concentrations above EPA
standards (400 ppm) are common
- Pb cannot be broken down or effectively
removed from soil
- Not just gardeners – but all urban residents
are at risk for exposure – especially kids
Cheng et al., (2015) Trace Metal Contamination in NYC Garden Soils

4. Solutions for Pb in Soil?
Can we remove Pb from soil?
(Can plants help us do this,
a.k.a phytoextraction?)
No, not safely
Good news – crops are usually safe!
(Just make sure to wash them)
Can we add amendments to
make Pb less toxic (bioavailable?)
Yes, but this can be tricky
Testing methods are disputed,
phosphorus can make arsenic more available…
but adding materials like compost is
still good for soil
Can we dig up and haul out soil?
Yes, if money’s not a constraint
Can we cover contaminated soil?
Absolutely!
So where do we get new soil?
?

5. Solution: NYC Clean Soil Bank (CSB) / PUREsoil NYC
- Created CSB
- Excavated sediments
- Tested sediments
through certified York
Analytical Laboratory
- Creates food scrap
compost used for
study
- Compost was
tested for
contaminants prior
to use
- Manages NYC
community gardens
- Provided space,
materials, and
gardener outreach for
study
- Created experimental
beds
- Grew crops
- Conducted soil and
plant analyses
- Conducted data
analyses
Sediments Community
Gardens
Experimental
Design & Testing
Compost

6. Solution: NYC Clean Soil Bank (CSB)
- CSB sediments and compost mixtures create viable
growing media
- Soil parameters indicate mixtures are suitable for edible
crops
- More than 33% of this compost / sediment mixture was
was adequate for yield
- Crops show no evidence of contamination
- Soil metal concentrations remained very low over initial
two years, but monitoring will continue
Egendorf et al., (2018) Constructed soils for promoting community
gardening and mitigating lead (Pb) Exposure:
the NYC Clean Soil Bank pilot study

7. ENYF 33%
in 2018
E 43rd St 33%
in 2018
What biological, chemical, and physical processes are going on in
these newly constructed soils over time and in different spaces?
How much carbon is being sequestered?
How might we optimize those conditions?

8. What is Soil Carbon
Sequestration?
• Removal of atmospheric CO2
by plants
• Storage of C as
• soil organic matter (SOM) or
soil organic carbon (SOC)
Lehman and Kleber (2015). Then contentious
nature of soil organic matter

9. How Does Soil Carbon Sequestration Occur?
• Inputs:
• Aggregation:
• Stable micro-aggregates
form through organo-
mineral complexes that
encapsulate C and
protect it against
microbial activities and
decomposition.
• Translocation into the
sub-soil:
• SOC moves into the sub-
soil and away from the
zone of disturbance by
anthropogenic activities
and erosional processes.
Lal (2004) Carbon sequestration to mitigate climate change Schmidt et al. (2011) Persistence of SOM as an ecosystem property

10. • Outputs:
• Decomposition and
respiration
• Mineralization and
oxidation
• Leaching and erosion
• Historical SOC losses
range from 40-90 Gt
• SOC depletion is a
reversible process
How is Carbon
Released
from Soil?
Rodale Institute (2009) The Nitrogen Cycle

11. Big Ideas on Soil
Carbon Sequestration
• C sequestration is dependent on environmental
factors and soil structure
• How do we manage and support soil
aggregating conditions, particularly in the urban
environment?
• Increases in C storage occur quickly with C depleted
sediments
• We have a very large supply of subsoil / glacial
sediments with the Clean Soil Bank (CSB) /
PUREsoil NYC
• What conditions optimize C increases over
time?

12. What happens over time as we construct new soils?

15. Raves Garden
Constructing Soil for Environmental and Social Justice
Glacial
Sediments
Compost Researchers Youth Community
Members
from with
Welcome to
a JUST SOIL project

16. CSB Generating Site
Jamaica, Queens
4/20/18
NY Hall of Science
4/20/18

17. NY Hall of Science 33% Compost Mixtures 4/24/18

21. NYCHA Ravenswood Seed Starting 5/7/18

22. NYCHA Ravenswood Bed Frame Building 5/14/18

37. Meso Scale: Legacy Lead Coalition
20+ organizations meet monthly
since January, 2016
How can a coalition build and support:
Clean Soil Distribution Network:
Connecting composters, agencies, orgs
Goal of creating multiple local hubs
Gardener/grower distribution networks
Critical Soil Education:
Biogeosociochemical Pb cycle (comic)
Revamped BMPs
Connect with k-12 garden ed networks
Soil Research:
Current pilot studies
Creating protocols for constructed soil research
Platform for long-term multi site studies

38. Macro Scale: Connecting with Other Regions
Mielke et al. (2011) Estimation of leaded (Pb)
gasoline’s continuing material and health
impacts on 90 US urbanized areas
100+ regions mapped for Soil
Pb (US and abroad)
Only 23 reported US soil Pb cover
interventions
(Laidlaw et al., 2017)
Strengthen / Build
Proximal / Distal Connections:
Currently work with 9 cities
Continue to map anthroposols / Constructed Technosols
Local Partnerships:
Framework for just interventions
Build connections with growers / soil stewards
Academic Resources:
Compile data on soil creation
Study local particularities

39. Collaborating Across Scales of Time and Space
Time
Space
Carbon Sponge
+ JUST SOIL
Legacy Lead
Coalition
New Soil Layer:
Conscious Anthropocene Marker How can affected
communities
effectively construct soils
to sequester
lead and carbon?
How can community and
scientific partnerships
further these efforts to
reduce waste and
contamination exposure,
and promote
environmental justice,
food justice, and all the
benefits of urban green
space?How might we work together?

40. Constructing Soil:
The Key Element
for Sequestering
Lead and Carbon
6th National Cultivating Community
Composting Forum
Sara Perl Egendorf
May 13, 2019
Thank you for your attention!
segendorf@gradcenter.cuny.edu
IG @just_soil / Twitter @justsoilnyc