O-64 Effects of biochar-amended tropical soils on herbicide pollution: column leaching studies
Author(s):
G Aldana, E Lopez-Capel, D Werner
Type Of Study:
- Experimental or Intervention Study
- Quantitative
Year of Presentation:
2023
Objective: To performing column leaching studies to determine whether biochar-amended tropical soils can reduce
herbicide contamination.
Methods: Column leaching experiments followed the OECD 312 guidelines for testing of chemicals – leaching in soil columns. Three different soil types were sampled from agricultural sites in Belize. Pyrex glass columns were separately hand packed with soils amended with 2.5% (w/w) rice husk biochar. Extreme rainfall events were simulated to present a worst case scenario of herbicide leaching event. Herbicides atrazine and diuron were added to the column to determine whether biochar-amended soils will aid in leaching reduction. Leachate samples were analysed using Liquid Chromatography-Mass Spectrometry.
Results: The application of biochar to both loam and sandy silt loam soils reduced the leaching of both atrazine and diuron. Column leaching linear Kd (m3/kg) of atrazine in biochar amended loam was 0.15 and for biochar amended sandy silt loam was 0.8. Leachate analysis showed that samples collected from the biochar-amended soils had a much lower herbicide concentration than soils that were not amended with biochar. The presence of biochar increased sorption sites in the soil matrix, that stopped the herbicides from leaching.
Conclusion: Column leaching studies showed that tropical soils amended with 2.5% rice husk biochar can reduce the leaching of atrazine and diuron, thus protecting human health and the natural environment from water contamination.