Ecotoxicity of alkaline residue from the pulp and paper industry to soil faunal organisms.

The increased production and expanding demand for cellulosic products have required companies to provide solutions for the proper disposal of generated residues without compromising soil quality. In this context, the current research aimed at evaluating the ecotoxicological impacts of dregs application in subtropical soils. The experiments were carried out with the earthworm Eisenia andrei, the springtail Folsomia candida, and the potworm Enchytraeus crypticus in two subtropical soils (Neosol and Cambisol) collected in the southern region of Brazil. The considerable differences in texture and organic matter content motivated the choosing of these soils. The reproductive rate of all organisms was influenced, with varying EC50 values depending on the soil type. However, more pronounced effects were observed for Neosol. The springtail F. candida proved to be the most sensitive to contamination (EC50 = 5.8 g kg-1 for Neosol and 48.5 g kg-1 for Cambisol), followed by the earthworm E. andrei (EC50 = 62.4 g kg-1 for Neosol and 129.5 g kg-1 for Cambisol) and the potworm E. crypticus (EC50 = 67.2 g kg-1 for Neosol and 230.4 g kg-1 for Cambisol). As a result, while dregs can be used to correct soil acidity, they have been shown to have negative effects on important organisms responsible for functions critical to maintaining ecosystem quality.