Deposits of fine wastes from dimension stone processing and quality of the phreatic aquifer

ABSTRACT

The processing of dimension stone blocks for the production of plates generates a thin residue with the Dimension Stone Processing Slurry (DSPS) discarding. Although there are various possibilities for the use of the wastes from DSPS in other production processes, these effluents have been accumulated in the environment for decades, forming today’s environmental liabilities of the dimension stone industry. This work aimed to describe the groundwater quality of a shallow aquifer in three selected deposits in Cachoeiro de Itapemirim County, an important producer of Espírito Santo State, in Brazil. Samples of waste were collected through drill holes that penetrated the deposits up to the bottom. Chemical analyses through X-ray fluorescence spectrometry and tests for waste classification, according to the Brazilian Association of Technical Standards, were conducted. Groundwater monitoring wells were constructed in each studied area, one of them upstream of the deposit, three downstream, and one inside the deposit. In situ groundwater analyses were conducted to measure pH, electrical conductivity, and total dissolved solids. In the laboratory, alkalinity, chloride, total phenol, and metals were also analyzed. The residues deposited can be considered inert and the pH-values tend to be attenuated/not corrosive. Nevertheless, attention should be paid to the levels of Al, Fe, and Mn in the environmental liability areas. Special attention should be given to the phenolic compounds once the risks involved are high. The segregation between the polishing and sawing wastes is an action that could avoid environmental impacts.

Keywords:
abrasive slurry; environmental geochemistry; waste management