Research & reports

Wendy J. Heiger-Bernays, Alicia Fraser, Valerie Burns, Kerry Diskin, Diedre Pierotti, Kian Merchant-Borna, Michael D. McClean, Daniel J. Brabander, H. Patricia Hynes · Scholarworks (University of Massachusetts Amherst) · United States (Boston)

This study identified the nature and extent of soil contamination by polycyclic aromatic hydrocarbons (PAHs) from railroad ties and arsenic from chromated copper arsenate (CCA) pressure-treated lumber in a representative community garden in Boston. Elevated levels of PAHs and arsenic were present in the gardens studied, with these timbers serving as a continuous source of contaminants. This is the first study to investigate contaminants other than lead and evaluate the effect of adding city compost on select soil contaminants in urban garden soil.

Jordi Guimera Garcia, Natalie Bray, Yowhan Son, Aleah L. Butler-Jones, Sara Perl Egendorf, Jenny Kao‐Kniffin · Journal of Urban Ecology · United States (New York City)

In New York City, a study investigated plant growth (tomato, pepper, kale) in soils constructed from four municipal composts mixed with sediments from the NYC Clean Soil Bank, to assess the potential for safe urban agricultural soils. While Clean Soil Bank sediments enhanced plant growth when mixed with BRL compost, they also negatively impacted tomato aboveground biomass production by 29% in LES compost and tomato plant height by 18% in QBG compost, indicating variable effects depending on compost properties.

Chammi P. Attanayake, Ganga M. Hettiarachchi, Mónica Palomo, Gary M. Pierzynski, Blanca Calderón · ACS Agricultural Science & Technology · United States

The effect of limestone and composted manure on lead (Pb) in vegetables and Pb bioaccessibility was assessed in a contaminated urban garden (total Pb ~200 mg kg⁻¹). Amendments did not affect Pb in vegetables or Pb bioaccessibility. Peeling reduced Pb concentration in radish by half, and removing surface dust reduced Pb in leafy vegetables by 40-50%. Daily Pb intake from consuming lettuce and carrot/beetroot from this garden was approximately 1.5 times higher than the interim reference level proposed by the U.S. Food and Drug Administration.

Candis M. Hunter, Dana Williamson, Melanie Pearson, Eri Saikawa, Matthew O. Gribble, Michelle C. Kegler · Local Environment · United States (Atlanta)

This study used five focus groups with Atlanta community garden leaders to investigate perspectives on composting, hygiene, and mulching, which are practices to reduce exposure to soil contaminants. Gardeners cited a need for more funding, volunteers, and training. A primary barrier to composting and mulching was concern about contamination of source materials, and participants did not directly link these practices to reducing soil contaminant exposure. Hygiene challenges included concerns about beneficial bacteria, inadequate water access, and limited supplies.

Josh Beniston · The Knowledge Bank (The Ohio State University) · United States (Ohio)

An experiment on assessing and managing soil quality for urban agriculture was conducted during the 2011 and 2012 growing seasons on demolished vacant urban lots in Youngstown, Ohio. Soil compaction was identified as a primary constraint, with high bulk density values of 1.79 g cm⁻³ for in-ground plots and 1.55 g cm⁻³ for raised beds. Crop yield data from 2011 showed that both compost-amended and compost + biochar-amended plots had significantly greater crop yields than control plots, with compost + biochar plots achieving the highest harvest index values.