Enhanced Dissipation of Selected Herbicides in a Simulated Organic Matrix Biobed: A System to Control On‐Farm Point‐Source Pollution

Abstract

Most farms have a centralized location to fill spray tanks with pesticides and to flush and clean application equipment. These sites, depending on the frequency of use, could be significant sources of surface and groundwater contamination. One approach to minimize this contamination is to install a treatment system, such as a biobed. This study sought to construct a biobed and test the effects of different biomix materials in enhancing the dissipation of herbicides widely used in crop production. The four types of biomix evaluated had mixing ratios by volume of (1) 12.5% straw:62.5% soil:25% peat, (2) 25% straw:50% soil:25% peat, (3) 12.5% straw:62.5% soil:25% compost, and (4) 25% straw:50% soil:25% compost. The dissipation rates of acetochlor, atrazine, pendimethalin, and trifluralin at different incubation times over 90 d were evaluated. The dissipation of atrazine and pendimethalin in the biomixes were faster than in soil. The half-lives for atrazine were 27.8 d in soil and 14.3 to 20.2 d in the biomixes and those of pendimethalin were 25.5 d in soil and 11.9 to 14.8 d in the biomixes. The dissipation rates and half-lives of acetochlor were similar to those in soil; the trifluralin dissipation rates were slower in the biomixes. The phenol oxidase activity was higher in the peat biomixes than in those containing compost. The results showed that biobed materials, especially those with peat, are effective in degrading selected herbicides.

Plants affect the dissipation and leaching of anilide pesticides in soil mesocosms: Insights from compound-specific isotope analysis (CSIA)

“…DT 50 values for ALA inferred from vineyard mesocosms were similar to reference values, while the values for forest mesocosms were similar to those reported in field studies and higher than reference values (up to 21 days, University of Hertfordshire, 2019) (SI-A), also reflecting the higher affinity of ALA to forest SOM compared to ACE (ALA K OC > ACE K OC ). Lower ACE and ALA dissipation in forest than in vineyard mesocosms was consistent with slower dissipation rates (Table S5, SI-N) and with results of a simulated organic matrix biobed experiment with high organic matter content (Chu and Eivazi, 2018).…”

Environmental Indicator Principium with Case References to Agricultural Soil, Water, and Air Quality and Model‐Derived Indicators

“…One approach to minimizing such point-source pollution is to install biobeds to dissipate pesticides. Chu and Eivazi (2018) constructed biobeds and tested the effects of four types of biomixes (a mixture of straw, topsoil, peat, or compost in different proportions, or soil alone [control]), on dissipation of four commonly used herbicides (acetochlor, atrazine, pendimethalin, and trifluralin) under standardized incubation conditions. Atrazine and pendimethalin dissipated faster in the biomixes than in soil, showing greatly reduced half-lives (DT 50 ).…”