Research & reports

Malone M., Johnson B., Richard SI., Garcia N., Hamlin S. · Journal of Environmental Management · United States (Seattle)

Compares heavy-metal concentrations in vegetables grown in urban community gardens in the Seattle metropolitan area with produce from the grocery stores participants regularly used — a question set by the partnering farmers themselves. Metal concentrations frequently exceeded health guidelines in both, but were generally higher in the community-garden produce. Cadmium and lead posed the greatest risk and may exacerbate health risks for some populations.

Robert J. Moriarity, Meaghan J. Wilton, Eric N. Liberda, Tim Drew, Ada John, Howard Jeddore, Atanu Sarkar, Jim D. Karagatzides, Leonard J. S. Tsuji · Journal of Agriculture Food Systems and Community Development · Canada (Newfoundland)

This study aimed to develop safe community garden sites in Miawpukek First Nation, Newfoundland, Canada, addressing potential soil contamination. Soil testing revealed inorganic arsenic levels exceeding Canadian agricultural guidelines. Hügelkultur-style raised beds with imported soil were used, resulting in undetectable arsenic in potatoes grown there, while potatoes from contaminated soil exceeded safety limits. Kale grown in both raised beds and native soil remained within safety limits.

Ainsley C. McStay, S.L. Walser, Eric C. Sirkovich, Nicolas Perdrial, Justin B. Richardson · Journal of Environmental Quality · United States

This study evaluated portable X-ray fluorescence (pXRF) measurements of macronutrients, micronutrients, and toxic elements (As, Pb) in soils and plants from 10 urban community gardens across the eastern United States. It found that pXRF and traditional methods provided agreeable estimates for some elements (Mn, Cu, Zn, Pb) but not for macronutrients (Ca, K, P). While pXRF is an accurate tool for screening Mn, Cu, Zn, and Pb, macronutrients were poorly estimated in fruits, leaves, and roots, and genus-specific and garden-specific factors may be important for plant uptake models.

Moisés Savian, Mari Inês Caríssimi Boff, Pedro Boff · Cadernos de Agroecologia · Brazil

This study evaluated Brazilian scientific production from 2009 to 2018 on urban agriculture's contribution to food and nutritional security, analyzing 34 selected articles out of 612. It found that while agrobiodiversity is present in urban agriculture areas, pesticide use is a reality in some crop plots. The research suggests urban agriculture must be based on agroecology to avoid environmental contamination and produce healthy food.

Katyelle Rafael, Ariella Andrade Marchioro, Cristiane Maria Colli, Bruna Tiaki Tiyo, Fernanda Ferreira Evangelista, Renata Coltro Bezagio, Ana Lúcia Falavigna-Guilherme · Transactions of the Royal Society of Tropical Medicine and Hygiene · Brazil

This study genotyped Giardia duodenalis in raw-eaten vegetables (crisp lettuce, regular lettuce, kale, chicory, and rocket) sampled from street markets and community vegetable gardens in an urban area of southern Brazil. Researchers analyzed 130 samples from street markets and 130 from community gardens (260 total), washing them in Tween 80 solution, filtering through a cellulose acetate membrane, amplifying the GDH gene by semi-nested PCR, and genotyping positive samples by PCR-RFLP. 7.3% (19/260) of samples tested positive for G. duodenalis, from both street markets (10/130) and community gardens (9/130), including both organic and non-organic products. Assemblage AI predominated, but assemblages B and E, which carry zoonotic potential, were also found. The study concludes this points to a need for investigating commercially sold raw vegetables and establishing stricter quality control.

Adam J Long · Scholarship @ Claremont (The Claremont Colleges) · United States (Washington, DC)

This study investigated heavy metal soil contaminants in 13 urban community gardens in Washington, DC, analyzing 45 soil samples using X-ray fluorescence (XRF). While most samples fell below US EPA action levels for common contaminants, high concentrations of lead (above the US EPA action level of 400 ppm) were found in the native soil of three garden sites, meriting concern due to potential health problems in children.