Examining Trace Element Concentrations in Kale from Tucson: Community Gardens Vs. Grocery Stores.

EXAMINING TRACE ELEMENT CONCENTRATION IN FROM TUCSON: COMMUNITY GARDENS VS. GROCERY STORES Hanna Hard1and Monica Ramirez-Andreotta1,2 1Department of Soil, Water, and Environmental Science andÊ2Mel and Enid Zuckerman College of Public HealthÕs Division ofÊCommunity, Environment & Policy, University of Arizona, Tucson AZ Home and community gardening are on the rise, and it is critical to assess the safety and quality of locally grown produce. This project examined the concentration of a suite of elements in kale (part of the Brassicaceae plant family) from two sources in Tucson, Arizona: community gardens and local grocery stores. The study compared the uptake of Al, Cr, Ni, Cu, Zn, As, Se, Cd, Pb, and Mo in kale that was grown in an urban garden versus a conventional commercial farm. The store-bought kale was from farms located in Arizona, Mexico, and California and the community gardens were located throughout the Tucson metropolitan area. Grocery stores were selected based on proximity to gardens, assuming the consumer lives near the garden and that the garden would be an alternative source of produce. Dried and ground kale samples were microwave digested and analyzed via inductively coupled plasma mass spectrometry. Median concentrations in store-bought kale exceeded median concentrations in garden-grown kale for all metals analyzed except Zn, Pb, and Mo. Using an exposure assessment, none of the samples (from neither garden nor stores) analyzed had concentrations that reached U.S Environmental Protection Agency (US EPA) human reference doses within one serving of kale. When anticipating a higher consumption pattern (five-six servings of kale per day), Mo, Se, and Cd did reached the US EPA human reference doses of 0.005 milligrams per kilogram body weight per day (mg/kg/day), 0.0003 mg/kg/day, and 0.001 mg/kg/day, respectively, in some samples.