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Insecticide washoff from concrete surfaces: characterization and prediction
Yuzhou Luo1, Brant C Jorgenson, Dang Quoc Thuyet
1Department of Pesticide Regulation, California Environmental Protection Agency , Sacramento, California, 95812, United States.
Environmental Science & Technology
|December 6, 2013
Summary
Pesticide runoff from urban surfaces contaminates waterways. This study developed a model to predict pesticide washoff from concrete, improving urban environmental risk assessments.
Area of Science:
- Environmental Chemistry
- Urban Hydrology
- Ecotoxicology
Background:
- Pesticide runoff from impervious surfaces is a major source of aquatic contamination in urban areas.
- Understanding off-site transport processes is crucial for effective mitigation strategies.
Purpose of the Study:
- To comprehensively study pesticide washoff from concrete surfaces.
- To develop and validate a predictive model for pesticide buildup and washoff.
Main Methods:
- Conducted controlled rainfall experiments to measure washoff loads of insecticides.
- Developed a semimechanistic model incorporating pesticide-specific parameters and time dependencies.
- Applied first-order kinetics and Fick's second law for buildup and washoff processes.
Main Results:
- The model accurately predicted pesticide mass loads and temporal variations for diverse chemical properties (log KOW = 0.6-6.9).
- Successful prediction across single and repeated rainfall events (1-7 times) and extended set times (1.5 h to 238 days).
Conclusions:
- Physicochemical properties alone are insufficient for accurate risk assessment of urban pesticide applications.
- Additional parameters derived from washoff experiments are essential for robust environmental risk assessments.
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