Evaluation of the removal efficacy of three fungicides by biomixtures: impact of bioaugmentation by plant growth promoting rhizobacteria and zeolite fortification

Abstract

ABSTRACT Following their entrance into natural water reservoirs, the use of pesticides may adversely affect human health and the environment. Biobeds facilitate decontamination of agricultural wastewaters. Bioaugmentation could enhance biodegradation of pesticides and addition of an adsorbent, such as natural zeolite, may increase biobed efficacy. In this study, the bioaugmentation utility of Pseudomonas putida (biomixture A) and the impact of zeolites supplement (biomixture C) in biomixtures contaminated with the fungicides fluopyram (20 mg/kg), myclobutanil (10 mg/kg), and triticonazole (30 mg/kg) were examined. A biomixture devoid of zeolites and inoculant was used as control (biomixture B). Bioaugmentation enhanced the dissipation rate of all fungicides (DT50 values of 9.5, 7.7, and 10.5 days for myclobutanil, fluopyram, and triticonazole, respectively), contrary to zeolite-treated samples in which the dissipation was prolonged. According to α-diveristy results, bioaugmentation treatment displayed higher microbial diversity than control samples, while the highest diversity was recorded in the case of natural zeolites. The results of β-diversity showed that bioaugmentation and natural zeolites affected microbial diversity during the first days of the experiment via the support of gammaproteobacteria (Proteobacteria) growth.