Bioavailability of humic substance-bound mercury to lettuce and its relationship with soil properties

The bioavailability of humic substance-bound mercury (HS-Hg) in relation to soil properties was investigated using lettuce (Lactuca sativa var. Angustana irish). Results showed fulvic acid-bound Hg (FA-Hg) was an important source of Hg for lettuce. The availability of added Hg to the lettuce depends on the supply power of added Hg and the absorption capacity of the lettuce. Acidic soil, light soil texture. and the amount of humic substances and available nutrients enhance Hg availability. This suggests that humic substance-bound Hg poses greater risk to human health through food chain in sandy, acidic, and fertile soils.