Related Experiment Videos
Sorption behavior of prochloraz in different soils
H Rütters1, A Höllrigl-Rosta, R Kreuzig
1Institute of Ecological Chemistry and Waste Analysis, Technical University of Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany.
Journal of Agricultural and Food Chemistry
|December 20, 1999
Summary
Soil organic matter and pH significantly influence prochloraz fungicide sorption. Lower pH and higher organic matter increase prochloraz binding, with nonlinear sorption observed. Metabolites show reduced sorption compared to prochloraz.
Area of Science:
- Environmental Chemistry
- Soil Science
- Agrochemicals
Background:
- Prochloraz (PCZ) is an imidazole fungicide widely used in agriculture.
- Understanding the environmental fate of pesticides, including their sorption behavior in soils, is crucial for risk assessment.
- Soil properties like organic matter and pH are known to affect pesticide sorption.
Purpose of the Study:
- To investigate the sorption behavior of the fungicide prochloraz (PCZ) in various soil types.
- To determine the influence of soil organic matter content and pH on PCZ sorption.
- To characterize the sorption isotherms and compare the sorption of PCZ with its metabolites.
Main Methods:
- Batch equilibrium experiments were conducted using different soils to study prochloraz sorption.
- Soil organic carbon (%OC) and pH were analyzed for their correlation with sorption coefficients (Kd).
- Sorption isotherms were generated, and the Freundlich model was applied to describe the sorption data.
- Sorption of two prochloraz metabolites (PCZ-formylurea and PCZ-urea) was also evaluated.
Main Results:
- Soil organic matter content was the primary factor controlling prochloraz sorption, with Kd values ranging from 56 to 552 and Koc values from 7273 to 16250.
- Soil pH significantly influenced PCZ sorption, with stronger sorption observed at lower pH values (pKa = 3.8).
- Sorption isotherms followed the Freundlich model, indicating nonlinear sorption, and exponents were significantly less than unity.
- Prochloraz metabolites exhibited lower sorption coefficients (Kd) compared to the parent compound.
Conclusions:
- Prochloraz sorption in soils is predominantly governed by soil organic matter and soil pH.
- The fungicide exhibits nonlinear sorption behavior, which is pH-dependent, with increased sorption under acidic conditions.
- Metabolites of prochloraz are less sorptive than the parent fungicide, suggesting potentially different environmental mobility.