Arsenic, Lead, and Cadmium Contamination of Crops By Fly Ash in China.

China is currently the world’s largest energy consumer in the world, where over 65% of the country’s installed electricity capacity is fueled by coal combustion. China is also the world’s largest producer and consumer of coal in the world, accounting for nearly half of the world’s coal consumption. During the coal combustion process, many toxic by-products  are produced and released from the stacks, which can then deposit on agricultural land near the power plant.  In this study, we examine the potential impact of fly ash on crop yield in Wuhan, Hubei Province, China. Utilizing a bottom up approach, we determine the potential amount of As, Pb, and Cd incorporated into lowland (i.e., lotus and rice) versus upland (i.e., vegetables) crops due to fly ash contributed metals in cropland soils. First, we determine the impact of coal composition and particular control devices on the amount of fly ash produced utilizing the Integrated Environmental Control Model (IECM). An estimate of the composition of fly ash (based on the coal composition) is then predicted by thermodynamic equilibrium calculations. The resulting information regarding the concentration of As, Pb, and Cd  in the fly ash is entered into an atmospheric transport model which determines the mass of fly ash deposited as a function of distance from the stack. Transport modeling results, land cover data, and topographic information are incorporated using GIS to determine the croplands affected by fly ash deposition. Furthermore, we determine the contribution of fly ash and coal products to soil Pb by comparing Pb206/Pb207 isotopic ratios of coal and fly ash taken from the power plant to that of soils samples along the preferential windpath downwind from the power plant stack.