Studies Regarding the Decrease of Heavy Metal Accumulations in Herbaceous Plants Tissues Grown on Fly Ash Dumps

Abstract

Fly ash dumps are an environment difficult to vegetable because of the high content of inert materials (metal oxides in excess of 95-99%) and it does not contain any nutrients based on N and P. Carbon compounds resulting from incomplete combustion lignite are and not easily assimilated by plants. Fly ash properties do not allow water retention in the upper layer. The addition of fertilizers as biosolids (municipal sludge) and a material in type of indigenous volcanic tuff, with capacity of water retention and gradual release based on plants necessities, allowing both plant growth and protection against excessive accumulation of toxic metals in air tissues. A field experiment was conducted on a lignite fly ash dump, on two types of experimental parcels, control parcels and experimental parcels (fertilized with biosolids and treated with volcanic tuff). In this study, through work technique, were obtained in case of plots fertilized with biosolids and treated with tuff volcanic indigenous, reduction of metal accumulation in aerial tissues of the examined species of: 73-94% for Pb, 37-50 % for Cr, 28-43% for Ni and 12,5-22% in comparison with control plots.

Keywords

• accumulation decrease
• heavy metals
• fly ash dumps
• herbaceous plants