Human health risks of Pb and As exposure via consumption of home garden vegetables and incidental soil and dust ingestion: A probabilistic screening tool

The consumption of home grown vegetables may represent a significant exposure pathway for arsenic (As) and lead (Pb) relative to direct incidental ingestion of soil, thus a probabilistic screening tool for estimating these exposures was developed using regression models relating co-located soil and home garden (HG) vegetable concentrations of Pb and As established from multiple independent studies and 2-dimensional Monte Carlo analyses. For high-quantity consumers of HG vegetables (i.e., the upper 95th percentile of consumers in the general population), the HG consumption pathway can be as significant as incidental soil and dust ingestion for inorganic As and, therefore, should be considered when developing generic health-based soil criteria in residential settings. Predicted Pb Hazard Quotient (HQ) estimates among young children resulting from HG consumption were 4- to 10-fold lower than exposures resulting from direct incidental soil and dust ingestion. The difference in soil/dust ingestion rates used to characterize young children (the 95th percentile of 202 mg/d) versus a lifetime residential receptor (the 95th percentile of 30 mg/d) was a primary factor contributing to the relative differences observed between HQ and incremental lifetime cancer risk (ILCR) resulting from these two exposure pathways for lead Pb and inorganic arsenic As, respectively.

► Home garden vegetables can be a significant exposure route for humans for inorganic As.
► At a specific site, it is similar in size to incidental soil and dust ingestion.
► Should be considered when developing generic health-based soil criteria in residential settings.
► Home garden vegetables are a much smaller exposure to Pb than incidental soil and dust ingestion.