Pollution is ubiquitous: Community-based quantitative human health risk assessment of metal(loid) exposure from contaminated garden plants and soils

Abstract

Communities across the world are attempting to practice food sovereignty, yet metal(loid) contamination of gardens may restrict one’s right to define their own relationship to the environment. To understand the human health risks associated with growing and eating plants in environmental justice communities, we aggregated environmental monitoring data at 231 sites from 10 participatory research projects. Using a Bayesian quantitative risk assessment, we simulated cancer and non-cancer health risks of ingesting garden soil and crops, and simulated a comparison to the U.S Food and Drug Administration's Total Diet Study (TDS) of conventionally-grown produce. Median hazard index (HI) – (sum of risks from 17 analytes and 20 exposure routes) - and increased excess lifetime cancer risks (IELCR) – (4 analytes, 20 exposure routes) - were 2.38 and 6.53 × 10⁻⁴ (6.53 out of 10,000) respectively. Key findings were that arsenic, manganese, copper, and barium contributed most to HI, at 29 %, 19 %, 11 %, and 9 % contribution respectively, while arsenic contributed most to IELCR at 95 % contribution. Collard greens, kale, turnip, radish, berries, string beans, cucumber, and squash had the highest risks. Community risks were slightly higher than TDS risks, except for nickel IELCRs. Consuming either home-grown produce or TDS produce poses substantial health risks. However, home-grown produce also contained higher levels of nutrients than TDS produce. Potential health benefits from gardening and eating home-grown produce, as well as an anti-colonial exposure assessment should be studied further. Individual action is not enough to protect human health; root causes of contamination such as industrialization and colonization must be addressed.