Do new cement-based mortars pose a significant threat to the aquatic environment?

Abstract

Nowadays, the use of multi-functional mortars has increased significantly, with interesting applications in the sustainable construction. In the environment, the cement-based materials are subjected to leaching, so the assessment of potential adverse effects upon aquatic ecosystem is necessary. This study focuses on the evaluation of the ecotoxicological threat and of a new type of cement-based mortar (CPM-D) and its raw materials leachates. A screening risk assessment were performed by Hazard Quotient methods. The ecotoxicological effects were investigated by a test battery with bacteria, crustacean, and algae. Two different procedures, Toxicity test Battery Index (TBI) and Toxicity Classification System (TCS), to obtain a single value for toxicity rank were used. Raw materials showed the highest metal mobility and in particular, for Cu, Cd and V potential hazard was evidenced. Leachate toxicity assessment evidenced the highest effects linked to cement and glass while the mortar showed the lowest ecotoxicological risk. TBI procedure allows a finer classification of effect linked to materials with respect to TCS which is based on worst case approach. A safe by design approach taking into account the potential and the effective hazard of the raw materials and of their combinations could allow to achieve sustainable formulations for building materials.

Keywords: Diatomite; Glass; Integration index; Pozzolan; Toxicity test.