Arsenic Abundance in Arugula and Kale of Coastal Maine Farms

Feher, Adam; Hall, Sarah; Disney, Jane

From the abstract: "Arsenic, an element with a litany of negative health effects caused by chronic exposure, is widely abundant throughout New England. Known sources of arsenic in this region include arsenical pesticide application throughout the 20th century and naturally occurring arsenic leached from the metasedimentary rocks of the region. Exposure is most common through the consumption of private well water, however some studies show elevated arsenic levels in Brassica family plants when grown in former orchards where pesticides were applied. Further, arsenic concentrations in water from dug wells at a local farm has been shown to increase during the growing season due to irrigation by arsenic-rich water sourced from the local drilled deep well. Thus, produce may be exposed to arsenic sourced from the soil or rock in the near surface or through irrigation waters. To understand if consumption of local arugula (Eruca vesicaria) and kale (Brassica oleracea) could contribute to chronic arsenic exposure, 11 samples (8 kale, 3 arugula) from 10 farms located near regions where metasedimentary bedrock is present and arsenical pesticides were likely to have been used in the past were collected for trace metal analysis. The arugula samples yielded arsenic concentrations of 0.05-1.26 mg kg-1 and kale yielded 0.02-0.17 mg kg-1. When considering a serving of 1 US cup of arugula (20g) and kale (67g), the arsenic that would be consumed by ingesting these produce range from 0.09-2.27 μg and 0.17-1.95 μg, respectively. For adult individuals, normal consumption of arugula and kale fall well below the benchmark dose for a 0.5% increased incidence of lung cancer of 3.0 μg kg-1 (of bodyweight) day-1 based upon epidemiological studies. As these samples were obtained by shopping at local farmers markets and grocers, the next steps of this project will include testing these or other crops as well as the soil and well water arsenic concentrations of the agricultural areas from which these crops were harvested."