Assessment of remediation of soils, moderately contaminated by potentially toxic metals, using different forms of carbon (charcoal, biochar, activated carbon). Impacts on contamination, metals availability and soil indices

Abstract

The present study aims to assess the effect of three forms of carbon, i.e., charcoal, biochar and activated carbon using as soil amendments (or soil conditioners) in two soils, an acid and alkaline one. For this purpose, a pot experiment was conducted by mixing six sub-samples for each soil along with the three amendments in the appropriate proportion. Total, pseudo-total and available metal concentrations were determined. Moreover, the BCR fractionation method was applied and the four soil fractions were identified. A significant decrease in the concentrations of all four metals in the water-soluble and exchangeable fraction (F1) was observed. At the same time, a high reduction was observed in the available concentrations of metals as well, ie those that were extracted after using the DTPA solution. Soil indices were also used in order to monitor and evaluate the possible ecological risk and the effect in metal concentrations after the application of the amendments. The use of the studied materials can be very promising soil conditioners, as they can precisely, economically, time-effectively, and efficiently can remediate soils, moderately contaminated with toxic metals.