Bioaccessibility of metals and human health risk assessment in community urban gardens. (September 2015)

• Record Type: Journal Article
• Authors: Izquierdo, M.; De Miguel, E.; Ortega, M.F.; Mingot, J.
• Is Part Of: Chemosphere. Volume 135(2015)
• Page Start: 312
• Page End: 318
• Publication Date: 2015-09
• Subjects: Bioaccessibility -- Metals -- Risk assessment -- Soil pollution -- Urban garden; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2015.04.079
• Languages: English
• ISSNs: 0045-6535

Abstract

Highlights: In a worst-case scenario, urban agriculture might pose an unacceptable risk. Estimates of bioaccessibility depend significantly on the calculation method used. Concentrations of metals vary depending on location and history of land use. Calcium carbonate controls the retention of most metals in soil in this study. Lead and chromium are the main contributors to risk for human health. Abstract: Pseudo-total (i.e. aqua regia extractable) and gastric-bioaccessible (i.e. glycine + HCl extractable) concentrations of Ca, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined in a total of 48 samples collected from six community urban gardens of different characteristics in the city of Madrid (Spain). Calcium carbonate appears to be the soil property that determines the bioaccessibility of a majority of those elements, and the lack of influence of organic matter, pH and texture can be explained by their low levels in the samples (organic matter) or their narrow range of variation (pH and texture). A conservative risk assessment with bioaccessible concentrations in two scenarios, i.e. adult urban farmers and children playing in urban gardens, revealed acceptable levels of risk, but with large differences between urban gardens depending on their history of land use and their proximity to busy areas in the city center. Only in a worst-case scenario in which children who use urban gardens as recreational areas also eat the produce grown in them would the risk exceed the limits of acceptability.