Does coal fly ash influence the growth of mangroves?

Abstract

A 1320-Megawatt capacity coal-fired power plant is establishing near the Ecologically Critical Area of the Sundarbans, Bangladesh. This power plant will generate 0.71 million tons of coal fly ash annually. Most of the previous studies concentrated on the soil amelioration and growth and yield of agricultural crops. However, this study investigated the effects of coal fly ash on the seedling growth (collar diameter, height, and biomass) of the major tree species (Bruguiera sexangula, Excoecaria agallocha, Heritiera fomes , and Xylocarpus mekongensis ) of the Sundarbans, as well as to assess the nutrient (N, P, and K) partitioning in their parts (leaf, stem, and roots). Mangrove soil and coal fly ash were mixed to get seven treatments say T0, T1, T2, T3, T4, T5, and T7, which contained 0%, 5%, 10%, 20%, 30%, 40% and 50% of fly ash (w/w) respectively. A significant ( p < 0.05) variation was observed among the species and treatments. Irrespective of species, almost similar growth for collar diameter, height, and biomass was observed for the treatments up to 10% of fly ash mixture. Collectively, a common decreasing trend for growth parameters was observed for the treatments of the higher proportion of fly ash. Similar to the growth pattern, nitrogen and potassium concentration in seedling parts showed a decreasing pattern at the higher pro- portion of fly ash. In conclusion, coal fly ash did not influence the growth of these studied mangrove species in a positive way but can tolerate up to 10% of fly ash mixture.