Health risk assessment of potential heavy metals bioaccumulation in specialty crops grown in farm soils amended with dredged material.

This research examined the potential human health risk associated with heavy metal bioaccumulation in specialty crops (lettuce, tomato, carrot) grown in soils amended with dredged material (DM) from the Toledo Harbor in Ohio, USA. The specialty crops were chosen to expand the scope of the study of dredged material, especially in Northwest Ohio. Previous studies have been focused on corn and soybeans, which are the major crops planted in the area. Also, lettuce, tomato, and carrot are more prominent in most garden farms in the Northwest Ohio area. The research objective was to determine the expected ecological risk coefficient, transfer factor, daily intake of metals, health risk index, and their implications in soil quality and human health when DM was used as a farm soil amendment. Our soil blends consisted of 100% farm soil (FS), 90% FS:10% DM, and 100% DM. The ecological risk assessment coefficient (takes into consideration the metal toxicity) indicated that Pb, As, Zn, Cr, Ni, Co, and Cu were below their respective threshold values suggesting low sensitive toxicity to organisms when exposed to the specific metal. In general, As exhibited preferential translocation into the edible biomass across all crops and treatments. We compared the consumption of As, Pb, Cd, and Cr in the specialty crops to published reference and background values, and the results indicated that the potential consumptions is below these values. The health risk indices for arsenic were above the maximum exposure value among all crops and treatments; however, the addition of DM decreased the risk. This study suggests that the use of the Toledo Harbor DM as farm soil amendment poses a low ecological risk and human health risk.