Chemical speciation of trace metals in atmospheric deposition and
impacts on soil geochemistry and vegetable bioaccumulation near a large
copper smelter in China
Abstract
Atmospheric deposition is an important source of trace metals to surface
environments, but knowledge about plant bioavailability of recently
deposited metals is limited. We performed a fully factorial soil and
atmosphere exposure experiment with three vegetables (radish, lettuce,
and soybean), which allowed to effectively distinguish impacts of
recently deposited metals (<1 year) from longer-term metal
exposures in soils. Results showed that recently deposited Cu, Cd, and
Pb accounted for 0.5-15.2% of total soil Cu, Cd, and Pb pools near
emission source, while they contributed 15-76% of Cu, Cd, and Pb
concentrations in edible parts of vegetables. The soil retention of
recently deposited metals (52-73%) presented as higher mobile fractions
than these previously present in soils (7-42%). These findings
highlight a preferential uptake and high rates of bioaccumulation of
deposited metals in vegetables and implicated that quick and potentially
stronger reduction can be achieved by reducing current atmospheric
source loads.