How much biochar is safe? Exploring potential ecotoxicological consequences for soil invertebrates and plants

Author(s)

da Costa, Vanessa Borges ; Ogura, Allan Pretti ; Alexandre, David Silva ; Soares, Matheus Bortolanza ; Alleoni, Luis Reynaldo Ferracciu ; Espindola, Evaldo Luiz Gaeta ; da Silva Pinto, Thandy Junio

• Document type: Journal article
• Source: APPLIED SOIL ECOLOGY; v. 202, p. 9-pg., 2024-07-30.

Abstract

The application of biochar in soil has shown promising potential for mitigating the toxicity of contaminated soils due to its unique properties. However, the understanding of its adverse effects on soil biota remains limited. This study aimed to investigate the potential ecotoxicological effects of incorporating sugarcane straw biochar into clay and sandy soils. This research assessed three biochar dosages (2 %, 5 %, and 10 %) and their effects on four species: the springtails Sinella curviseta and Proisotoma minuta, the worm Enchytraeus crypticus, and the plant Eruca sativa L. The results revealed that biochar incorporation had positive effects on plant growth, increasing biomass, and shoot and root length in E. sativa, with more pronounced effects in clay soil. However, the effects on the survival, reproduction, and growth of springtails varied depending on the species and soil type, with a reduction in the survival of P. minuta in both soils (2,2 and 2,9 times lower in clay soil and sandy soil respectively) and S. curviseta only in clay soil (24 % to 36 % decrease). The reproduction of P. minuta decreased in both soils (34% -48 % in sandy soil and 50% -80% in clay soil), while the reproduction of S. curviseta decreased only at the lowest proportion of biochar in the clay soil (18 % decrease). For E. crypticus, biochar improved both survival and reproduction, especially in sandy soil (1.9 and 11 times greater respectively). Therefore, biochar has positive effects on worms and plants, indicating the potential to improve soil health and support ecosystem resilience, but it has deleterious effects on springtails at certain dosages. The effects of biochar amendments on soil characteristics and the effects of biochar-induced toxicity should be considered to avoid potential risks to representative species. The findings presented herein address lacunae in ecotoxicology by delineating safe concentrations of biochar for various soil species, thus paving the way for subsequent validation of optimal application doses. (AU)

• FAPESP's process: 22/08032-8 - Nanobiochar modified with thiol in the control of mercury biogeochemistry in the soil in the Amazon region contaminated by mining activity
• Grantee: Matheus Bortolanza Soares
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/14293-9 - Fate, interaction, and ecological effects of microplastics and pesticides in tropical freshwater environments
• Grantee: Thandy Júnio da Silva Pinto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 24/00791-2 - Ecotoxicological effects of the microplastic polyethylene and the pesticide imidacloprid, alone and in a mixture, on the aquatic invertebrates Daphnia similis (Cladocera) and Hyalella meinerti (Amphipoda)
• Grantee: David Silva Alexandre
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 21/14789-1 - Ecotoxicity and bioaccumulation of pharmaceuticals: evaluation of treatment in anaerobic bioreactors
• Grantee: Allan Pretti Ogura
• Support Opportunities: Scholarships in Brazil - Post-Doctoral