In Vivo Studies for Removal and Biodegradation of Glyphosate and Tricyclazole Using Biobeds

Abstract

Laboratory setup of biobeds was used to degrade sequentially applied glyphosate and tricyclazole. Biobeds prepared using glyphosate pre-exposed soil, without (BM) and with wheat straw biochar [WBCBM(1%) and WBCBM(5%)], inoculated with glyphosate degrading Bacillus piscis, were used in the study. Glyphosate (5000 µg) and tricyclazole (5000 µg) were applied in 100 mL water at a difference of 2 months. Periodic pesticide residues estimation in surface 2.5 cm biomixture suggested that 0 time residues of glyphosate of 44.21, 45.33, and 45.97 µg g⁻¹ in BM, WBCBM(1%), and WBCBM(5%) were degraded to 5.61, 0.65, and 7.06 µg g⁻¹ after 2 months, respectively. Similarly, initial surface residues of tricyclazole of 32.44, 33.30, and 31.77 µg g⁻¹ in respective biobeds decreased to 7.79, 2.22, and 1.13 µg g⁻¹, respectively after 2 months. After 5 months experiment was discontinued and pesticide residues in surface, middle, and bottom 5 cm sections of biobeds were estimated. No residues of glyphosate and metabolite aminomethylphosphonic acid (AMPA) were detected in BM and WBCBM(1%) biobeds, while 7.37% of initially applied glyphosate as glyphosate + AMPA remained undegraded in WBCBM(5%). Complete tricyclazole degradation was observed in WBCBM(5%) biobed, while 14.71% and 2.10% tricyclazole was undegraded in BM and WBCBM(1%) biobeds, respectively. Thus, wheat straw biochar's dose had varying effect on degradation of glyphosate and tricyclazole. The study suggested that bioaugmented biomixtures prepared using glyphosate pre-exposed soil and biochar can be exploited for detoxification of these pesticides in bio-purification systems.