Will wheat be damaged by heavy metals on exposure to coal fly ash?

Abstract

The mining industry and coal-fired power plants are among the major sources of atmospheric particles that cause air pollution. Can crops be damaged as they are exposed to foliar deposits of particulate matter enriched with various metal(loid)s from coal-mining regions? This study investigated the effects of atmospheric particles on wheat seedlings grown in a region north of Xuzhou, East China, where five coal mines, three coal-fired power plants, two large fly ash yards, and several coal yards coexist. More than two-thirds of the land area of this region is cropland. Atmospheric deposition analysis showed that the daily bulk deposition fluxes of Cr were generally higher in this region than those in other regions worldwide, and the highest fluxes were found in the area between the two-major coal-fired power plants. Wheat was grown under different soil and atmospheric conditions in the coal-fired region (north of Xuzhou) and a non-coal-fired region (south of Xuzhou). Heavy metal analysis showed that the accumulation of Cu, Cd, Pb, Zn, Cr, and As in the cell wall, cell organelles, and soluble fraction of wheat seedling shoots, particularly the percentage in the cell wall, was higher in the coal-fired region than in the non-coal-fired region. Analysis of the changes in the ultrastructure of seedling root and leaf cells revealed that atmospheric particles released in the coal-fired region damages the cellular structure of various parts of the wheat seedling and affects photosynthetic processes by damaging the chloroplasts.