Plants are immobile and thus have the capacity to detoxify and accumulate toxic heavy metals. Our research is focused on identifying the molecular mechanisms used by plants to detoxify and sequester toxic heavy metals and the metalloid arsenic. In urban “food deserts” (i.e., places where access to healthy fruits and vegetables is limited) many disadvantaged communities are creating urban gardens. Urban community gardens have increased in prevalence as a means to generate fresh fruits and vegetables in areas lacking access to healthy food options. However, urban soils in these communities can have high levels of toxic heavy metals and metalloids, including arsenic, lead, and cadmium, which can lead to health risks. In this study, fruit and vegetable samples grown at an urban community garden in Southeast San Diego, the Ocean View Growing Grounds, were sampled repeatedly over a multi-year time period in order to measure potential contamination of toxic heavy metals and metalloids and to develop solutions for this problem. Several of the fruit trees, including Black Mission fig, Mexican lime and Apple tree, showed substantial uptake of lead in the leaf samples but no measurable contamination in the fruit tissue in the community garden. Moreover, the vegetables that were grown directly in the soil at this community garden showed measurable levels of arsenic or lead in their edible leaf tissues. The subsequent introduction of raised beds eliminated detectable heavy metal or metalloid contamination in these crops during the monitoring period. In addition, several plant samples were taken from additional community gardens on grounds that once served as a military base, and such sites have historically shown detectable levels of heavy metal and metalloid contaminants in soil samples. Low levels of lead contamination in leaves of fruit trees were observed. Recommendations for facilitating the monitoring of edible tissues and for reducing risk will be discussed.

Toxic heavy metal and arsenic monitoring and mitigation in food crops at an urban community garden

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.